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Hydrostatic Weighing
Hydrostatic weighing, also referred to as underwater weighing, hydrostatic body composition analysis and hydrodensitometry, is a technique for measuring the density of a living person's body. It is a direct application of Archimedes' principle, that an object displaces its own volume of water. Method The procedure, pioneered by Behnke, Feen and Welham as means to later quantify the relation between specific gravity and the fat content, is based on Archimedes' principle, which states that: ''The buoyant force which water exerts on an immersed object is equal to the weight of water that the object displaces.'' Example 1: If a block of solid stone weighs 3 kilograms on dry land and 2 kilogram when immersed in a tub of water, then it has displaced 1 kilogram of water. Since 1 liter of water weighs 1 kilogram (at 4 °C), it follows that the volume of the block is 1 liter and the density (mass/volume) of the stone is 3 kilograms/liter. Example 2: Consider a larger block o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density
Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be used: \rho = \frac, where ''ρ'' is the density, ''m'' is the mass, and ''V'' is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume, although this is scientifically inaccurate this quantity is more specifically called specific weight. For a pure substance, the density is equal to its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging. Osmium is the densest known element at standard conditions for temperature and pressure. To simplify comparisons of density across different systems of units, it is sometimes replaced by the dimensionless quantity "relative den ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archimedes' Principle
Archimedes' principle states that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially, is equal to the weight of the fluid that the body displaces. Archimedes' principle is a law of physics fundamental to fluid mechanics. It was formulated by Archimedes of Syracuse. Explanation In '' On Floating Bodies'', Archimedes suggested that (c. 246 BC): Archimedes' principle allows the buoyancy of any floating object partially or fully immersed in a fluid to be calculated. The downward force on the object is simply its weight. The upward, or buoyant, force on the object is that stated by Archimedes' principle above. Thus, the net force on the object is the difference between the magnitudes of the buoyant force and its weight. If this net force is positive, the object rises; if negative, the object sinks; and if zero, the object is neutrally buoyant—that is, it remains in place without either rising or sinking. In simple words, Archim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert R
Albert may refer to: Companies * Albert Computers, Inc., a computer manufacturer in the 1980s * Albert Czech Republic, a supermarket chain in the Czech Republic * Albert Heijn, a supermarket chain in the Netherlands * Albert Market, a street market in The Gambia * Albert Music, an Australian music company now known as Alberts ** Albert Productions, a record label * Albert (organisation), an environmental organisation concerning film and television productions Entertainment * ''Albert'' (1985 film), a Czechoslovak film directed by František Vláčil * ''Albert'' (2015 film), a film by Karsten Kiilerich * ''Albert'' (2016 film), an American TV movie * ''Albert'' (album), by Ed Hall, 1988 * "Albert" (short story), by Leo Tolstoy * Albert (comics), a character in Marvel Comics * Albert (''Discworld''), a character in Terry Pratchett's ''Discworld'' series * Albert, a character in Dario Argento's 1977 film '' Suspiria'' People * Albert (given name) * Albert (surname) * P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lung Volumes
Lung volumes and lung capacities are measures of the volume of air in the lungs at different phases of the respiratory cycle. The average total lung capacity of an adult human male is about 6 litres of air. Tidal breathing is normal, resting breathing; the tidal volume is the volume of air that is inhaled or exhaled in only a single such breath. The average human respiratory rate is 30–60 breaths per minute at birth, decreasing to 12–20 breaths per minute in adults. Factors affecting volumes Several factors affect lung volumes; some can be controlled, and some cannot be controlled. Lung volumes vary with different people as follows: A person who is born and lives at sea level will develop a slightly smaller lung capacity than a person who spends their life at a high altitude. This is because the partial pressure of oxygen is lower at higher altitude which, as a result means that oxygen less readily diffuses into the bloodstream. In response to higher altitude, the body's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vital Capacity
Vital capacity (VC) is the maximum amount of air a person can expel from the lungs after a maximum inhalation. It is equal to the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume. It is approximately equal to Forced Vital Capacity (FVC). A person's vital capacity can be measured by a wet or regular spirometer. In combination with other physiological measurements, the vital capacity can help make a diagnosis of underlying lung disease. Furthermore, the vital capacity is used to determine the severity of respiratory muscle involvement in neuromuscular disease, and can guide treatment decisions in Guillain–Barré syndrome and myasthenic crisis. A normal adult has a vital capacity between 3 and 5 litres. A human's vital capacity depends on age, sex, height, mass, and possibly ethnicity. However, the dependence on ethnicity is poorly understood or defined, as it was first established by studying black slaves Slavery is the ownership ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Composition
In physical fitness, body composition refers to quantifying the different components (or "compartments") of a human body. The selection of compartments varies by model but may include fat, bone, water, and muscle. Two people of the same gender, height, and body weight may have completely different body types as a consequence of having different body compositions. This may be explained by a person having low or high body fat, dense muscles, or big bones. Compartment models Body composition models typically use between 2 and 6 compartments to describe the body. Common models include: * 2 compartment: Fat mass (FM) and fat-free mass (FFM) * 3 compartment: Fat mass (FM), water, and fat-free dry mass * 4 compartment: Fat mass (FM), water, protein, and mineral * 5 compartment: Fat mass (FM), water, protein, bone mineral content, and non-osseous mineral content * 6 compartment: Fat mass (FM), water, protein, bone mineral content, non-osseous mineral content, and glycogen As a rule, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States National Academy Of Sciences
The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the National Academy of Medicine (NAM). As a national academy, new members of the organization are elected annually by current members, based on their distinguished and continuing achievements in original research. Election to the National Academy is one of the highest honors in the scientific field in the United States. Members of the National Academy of Sciences serve '' pro bono'' as "advisers to the nation" on science, engineering, and medicine. The group holds a congressional charter under Title 36 of the United States Code. Congress legislated and President Abraham Lincoln signed an Act of Congress (1863) establishing the National Academy of Sciences as an independent, trusted nongovernmental institution, created for the purpose of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States National Research Council
The National Academies of Sciences, Engineering, and Medicine (NASEM), also known as the National Academies, is a congressionally chartered organization that serves as the collective scientific national academy of the United States. The name is used interchangeably in two senses: (1) as an umbrella term or parent organization for its three sub-divisions that operate as quasi-independent honorific learned society member organizations known as the National Academy of Sciences (NAS), the National Academy of Engineering (NAE), and the National Academy of Medicine (NAM); and (2) as the brand for studies and reports issued by the unified operating arm of the three academies originally known as the National Research Council (NRC). The National Academies also serve as public policy advisors, research institutes, think tanks, and public administration consultants on issues of public importance or on request by the government. The National Research Council, National Academy of Engineer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Ice
Sea ice arises as seawater freezes. Because ice is less density, dense than water, it floats on the ocean's surface (as does fresh water ice). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world's sea ice is enclosed within the polar ice packs in the Earth's polar regions: the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean. Polar packs undergo a significant yearly cycling in surface extent, a natural process upon which depends the Arctic ecology, including the Arctic sea ice ecology and history, ocean's ecosystems. Due to the action of winds, currents and temperature fluctuations, sea ice is very dynamic, leading to a wide variety of ice types and features. Sea ice may be contrasted with icebergs, which are chunks of ice shelf, ice shelves or glaciers that Ice calving, calve into the ocean. Depending on location, sea ice expanses may also incorporate icebergs. General features and dynamics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seawater
Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately of dissolved salts (predominantly sodium () and chloride () ions). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at ) because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about . The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was . Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measuremen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Composition
In physical fitness, body composition refers to quantifying the different components (or "compartments") of a human body. The selection of compartments varies by model but may include fat, bone, water, and muscle. Two people of the same gender, height, and body weight may have completely different body types as a consequence of having different body compositions. This may be explained by a person having low or high body fat, dense muscles, or big bones. Compartment models Body composition models typically use between 2 and 6 compartments to describe the body. Common models include: * 2 compartment: Fat mass (FM) and fat-free mass (FFM) * 3 compartment: Fat mass (FM), water, and fat-free dry mass * 4 compartment: Fat mass (FM), water, protein, and mineral * 5 compartment: Fat mass (FM), water, protein, bone mineral content, and non-osseous mineral content * 6 compartment: Fat mass (FM), water, protein, bone mineral content, non-osseous mineral content, and glycogen As a rule, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
