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HVLS Fan
A high-volume low-speed (HVLS) fan is a type of mechanical fan greater than in diameter. HVLS fans are generally ceiling fans although some are pole mounted. HVLS fans move slowly and distribute large amounts of air at low rotational speed– hence the name "high volume, low speed." Typical applications for HVLS fans fall into two classifications—industrial and commercial. In industrial applications, HVACR is often cost prohibitive or impractical, and is usually only used for refrigerated warehouses or the manufacture of refrigerated or frozen foods. Fans installed in spaces like warehouses, barns, hangars and distribution centers can prevent heat stress, increase worker comfort and the productivity of both workers and livestock. HVLS fans are also used in commercial spaces, where air conditioning is more common, but increased air movement from ceiling fans can cost-effectively augment occupant comfort or prevent stratification. Typical commercial applications include shopping ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Office Buildings
An office is a space where the employees of an organization perform administrative work in order to support and realize the various goals of the organization. The word "office" may also denote a position within an organization with specific duties attached to it (see officer or official); the latter is an earlier usage, as "office" originally referred to the location of one's duty. In its adjective form, the term "office" may refer to business-related tasks. In law, a company or organization has offices in any place where it has an official presence, even if that presence consists of a storage silo. For example, instead of a more traditional establishment with a desk and chair, an office is also an architectural and design phenomenon, including small offices, such as a bench in the corner of a small business or a room in someone's home (see small office/home office), entire floors of buildings, and massive buildings dedicated entirely to one company. In modern terms, an office ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Inventions ...
The following articles cover the timeline of United States inventions: * Timeline of United States of America inventions (before 1890), before the turn of the century * Timeline of United States inventions (1890–1945), before World War II * Timeline of United States inventions (1946–1991), during the Cold War * Timeline of United States inventions (after 1991), after the dissolution of the Soviet Union {{DEFAULTSORT:Timeline of United States Inventions United States inventions United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Movement And Control Association
The Air Movement and Control Association International, Inc. (AMCA) is an international trade body that sets standards for Heating, Ventilation and Air Conditioning (HVAC) equipment. It rates fan balance and vibration, aerodynamic performance, air density, speed and efficiency. AMCA was formed in 1955 from several earlier trade associations which could be tracked back to the fan-testing requirements of the US Navy in 1923. It is a nonprofit organization that issues over 60 publications and standards, including testing methods, a Certified Ratings Program (CRP), application guides, educational texts, and safety guides. Membership and Activities AMCA membership is open to any company that manufactures or holds the design of a product that falls under the AMCA scope. AMCA publications and standards are developed when sufficient interest has been expressed by AMCA members. Publication and standard writing committees are composed of volunteers, which include both AMCA members and in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag (physics)
In fluid dynamics, drag, sometimes referred to as fluid resistance, is a force acting opposite to the direction of motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers, two solid surfaces, or between a fluid and a solid surface. Drag forces tend to decrease fluid velocity relative to the solid object in the fluid's path. Unlike other resistive forces, drag force depends on velocity. Drag force is proportional to the relative velocity for low-speed flow and is proportional to the velocity squared for high-speed flow. This distinction between low and high-speed flow is measured by the Reynolds number. Drag is instantaneously related to vorticity dynamics through the Josephson-Anderson relation. Examples Examples of drag include: * Net force, Net Aerodynamic force, aerodynamic or Fluid dynamics, hydrodynamic force: Drag acting opposite to the direction of movement of a solid object such as cars, aircraft, and boat hulls. * Viscou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airfoils
An airfoil (American English) or aerofoil (British English) is a streamlined body that is capable of generating significantly more lift than drag. Wings, sails and propeller blades are examples of airfoils. Foils of similar function designed with water as the working fluid are called hydrofoils. When oriented at a suitable angle, a solid body moving through a fluid deflects the oncoming fluid (for fixed-wing aircraft, a downward force), resulting in a force on the airfoil in the direction opposite to the deflection. This force is known as aerodynamic force and can be resolved into two components: lift (perpendicular to the remote freestream velocity) and drag ( parallel to the freestream velocity). The lift on an airfoil is primarily the result of its angle of attack. Most foil shapes require a positive angle of attack to generate lift, but cambered airfoils can generate lift at zero angle of attack. Airfoils can be designed for use at different speeds by modifying their ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clark Y
Clark Y is the name of a particular airfoil profile, widely used in general purpose aircraft designs, and much studied in aerodynamics over the years. The profile was designed in 1922 by Virginius E. Clark using thickness distribution of the German-developed Goettingen 398 airfoil.Piccirillo, Albert, "The Clark Y Airfoil - A Historical Retrospective," SAE/AIAA paper 2000-01-5517, presented at the World Aviation Congress & Exposition, October 10, 2000, San Diego, California. The airfoil has a thickness of 11.7 percent and is flat on the lower surface aft of 30 percent of Chord (aircraft), chord. The flat bottom simplifies angle measurements on propellers, and makes for easy construction of wings. For many applications the Clark Y has been an adequate airfoil section; it gives reasonable overall performance in respect of its lift-to-drag ratio, and has gentle and relatively benign Stall (flight), stall characteristics. The flat lower surface is not optimal from an aerodynamic perspec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NFCC
The PFF National Challenge Cup is an annual single-elimination tournament, knockout association football, football competition in men's domestic Football in Pakistan, Pakistani football within the Pakistan football league system. It is organized by and named after the Pakistan Football Federation. Initially named as ''Inter Departmental Championship'', it was introduced in 1979 as a football tournament for departmental selections and Pakistan Armed Forces, armed forces teams excluded from the National Football Championship (Pakistan), National Football Championship of Pakistan''.'' Khan Research Laboratories F.C., Khan Research Laboratories have won the most titles (six). WAPDA F.C., WAPDA are the current champions, winning the 2023–24 PFF National Challenge Cup, 2023–24 edition courtesy of a 1–0 win against SA Gardens FC, SA Gardens in the final. Background Introduced in 1979 to offer nationwide competition to departmental selections and Pakistan Armed Forces, armed force ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schools
A school is the educational institution (and, in the case of in-person learning, the building) designed to provide learning environments for the teaching of students, usually under the direction of teachers. Most countries have systems of formal education, which is sometimes compulsory. In these systems, students progress through a series of schools that can be built and operated by both government and private organization. The names for these schools vary by country (discussed in the '' Regional terms'' section below) but generally include primary school for young children and secondary school for teenagers who have completed primary education. An institution where higher education is taught is commonly called a university college or university. In addition to these core schools, students in a given country may also attend schools before and after primary (elementary in the U.S.) and secondary (middle school in the U.S.) education. Kindergarten or preschool provide some s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Church (building)
A church, church building, church house, or chapel is a building used for Christian worship church service, services and Christian religion, Christian activities. The earliest identified Christian church is a house church founded between 233 AD and 256 AD. ''Church'' is also used to describe a Church (congregation), body or an assembly of Christian believers, while "the Church" may be used to refer to the worldwide Christian religious community as a whole. In traditional Christian architecture, the plan view of a church often forms a Christian cross with the centre aisle and seating representing the vertical beam and the Church architecture#Characteristics of the early Christian church building, bema and altar forming the horizontal. Towers or domes may inspire contemplation of the heavens. Modern churches have a variety of architectural styles and layouts. Some buildings designed for other purposes have been converted to churches, while many original church buildings have bee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Fan
A fan is a powered machine that creates airflow. A fan consists of rotating vanes or blades, generally made of wood, plastic, or metal, which act on the air. The rotating assembly of blades and hub is known as an '' impeller'', ''rotor'', or ''runner''. Usually, it is contained within some form of housing, or case. This may direct the airflow, or increase safety by preventing objects from contacting the fan blades. Most fans are powered by electric motors, but other sources of power may be used, including hydraulic motors, handcranks, and internal combustion engines. Mechanically, a fan can be any revolving vane, or vanes used for producing currents of air. Fans produce air flows with high volume and low pressure (although higher than ambient pressure), as opposed to compressors which produce high pressures at a comparatively low volume. A fan blade will often rotate when exposed to an air-fluid stream, and devices that take advantage of this, such as anemometers and wind t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shopping Malls
A shopping mall (or simply mall) is a large indoor shopping center, usually anchored by department stores. The term ''mall'' originally meant a pedestrian promenade with shops along it, but in the late 1960s, it began to be used as a generic term for the large enclosed shopping centers that were becoming increasingly commonplace. In the United Kingdom and other countries, shopping malls may be called ''shopping centres''. In recent decades, malls have declined considerably in North America, partly due to the retail apocalypse, particularly in subprime locations, and some have closed and become so-called " dead malls". Successful exceptions have added entertainment and experiential features, added big-box stores as anchors, or converted to other specialized shopping center formats such as power centers, lifestyle centers, factory outlet centers, and festival marketplaces. In Canada, shopping centres have frequently been replaced with mixed-use high-rise communities. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
