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Rebreathing
A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath. Oxygen is added to replenish the amount metabolised by the user. This differs from open-circuit breathing apparatus, where the exhaled gas is discharged directly into the environment. The purpose is to extend the breathing endurance of a limited gas supply, and, for covert military use by frogmen or observation of underwater life, eliminating the bubbles produced by an open circuit system and in turn not scaring wildlife being filmed. A rebreather is generally understood to be a portable unit carried by the user. The same technology on a vehicle or non-mobile installation is more likely to be referred to as a life-support system. Rebreather technology may be used where breathing gas supply is limited, such as underwater or in space, where the enviro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breathing Gas
A breathing gas is a mixture of gaseous chemical elements and compounds used for respiration. Air is the most common and only natural breathing gas, but other mixtures of gases, or pure oxygen, are also used in breathing equipment and enclosed habitats such as scuba equipment, surface supplied diving equipment, recompression chambers, high-altitude mountaineering, high-flying aircraft, submarines, space suits, spacecraft, medical life support and first aid equipment, and anaesthetic machines. Oxygen is the essential component for any breathing gas, at a partial pressure of between roughly 0.16 and 1.60 bar at the ambient pressure. The oxygen is usually the only metabolically active component unless the gas is an anaesthetic mixture. Some of the oxygen in the breathing gas is consumed by the metabolic processes, and the inert components are unchanged, and serve mainly to dilute the oxygen to an appropriate concentration, and are therefore also known as diluent gases. Most bre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frogmen
A frogman is someone who is trained in scuba diving or swimming underwater in a tactical capacity that includes military, and in some European countries, police work. Such personnel are also known by the more formal names of combat diver, combatant diver, or combat swimmer. The word ''frogman'' first arose in the stage name ''The Fearless Frogman'' of Paul Boyton in the 1870s and later was claimed by John Spence, an enlisted member of the U.S. Navy and member of the OSS Maritime Unit, to have been applied to him while he was training in a green waterproof suit. The term ''frogman'' is occasionally used to refer to a civilian scuba diver. Some sport diving clubs include the word ''Frogmen'' in their names. The preferred term by scuba users is ''diver'', but the ''frogman'' epithet persists in informal usage by non-divers, especially in the media and often referring to professional scuba divers, such as in a police diving role. In the U.S. military and intelligence community, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AP Diving
The scuba equipment manufacturer AP Diving or Ambient Pressure Diving, formerly known as A.P.Valves, is at Water-Ma-Trout in Helston, Cornwall, England. They produce a range of scuba and surface supplied diving equipment including buoyancy compensator (diving), buoyancy compensator jackets and the Inspiration diving rebreather range. Their products are very popular in Britain. The firm started in 1969 making a valve to allow a diver to breathe from a stabiliser jacket buoyancy compensator's inflation cylinder. They progressed to making divers' ABLJ, adjustable buoyancy life-jackets and stabiliser jackets, and then other diving equipment such as rebreathers. and diving accessories etc. They often exhibit at diving trade shows. Product lines *"Inspiration" rebreathers have been in production since 1997. The earliest model, now known as the Inspiration classic, reached the end of its product support life in April 2017 after 20 years. It has been superseded by more recent models usi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Diving Suits
An atmospheric diving suit (ADS) is a small one-person articulated submersible which resembles a suit of armour, with elaborate pressure joints to allow articulation while maintaining an internal pressure of one atmosphere. An ADS can enable diving at depths of up to for many hours by eliminating the majority of significant physiological dangers associated with deep diving. The occupant of an ADS does not need to decompress, and there is no need for special gas mixtures, so there is little danger of decompression sickness or nitrogen narcosis when the ADS is functioning properly. An ADS can permit less skilled swimmers to complete deep dives, albeit at the expense of dexterity. Atmospheric diving suits in current use include the Newtsuit, Exosuit, Hardsuit and the WASP, all of which are self-contained hard suits that incorporate propulsion units. The Hardsuit is constructed from cast aluminum (forged aluminum in a version constructed for the US Navy for submarine rescue); the u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossary Of Underwater Diving Terminology
This is a glossary of technical terms, jargon, diver slang and acronyms used in underwater diving. The definitions listed are in the context of underwater diving. There may be other meanings in other contexts. Underwater diving can be described as a human activity Human behavior is the potential and expressed capacity ( mentally, physically, and socially) of human individuals or groups to respond to internal and external stimuli throughout their life. Kagan, Jerome, Marc H. Bornstein, and Richard M. ... – intentional, purposive, conscious and subjectively meaningful sequence of actions. Underwater diving is practiced as part of an occupation, or for recreation, where the practitioner submerges below the surface of the water or other liquid for a period which may range between seconds to the order of a day at a time, either exposed to the ambient pressure or isolated by a pressure resistant suit, to interact with the underwater environment for pleasure, competiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Sea Level
Standard sea-level conditions (SSL), also known as sea-level standard (SLS), defines a set of atmospheric conditions for physical calculations. The term "standard sea level" is used to indicate that values of properties are to be taken to be the same as those standard at sea level, and is done to define values for use in general calculations. Atmospheric properties At SSL some atmospheric properties are: * Pressure, ''P'' = 101.325 kPa ⇔ 2116.2 lbf/ ft2 ⇔ 14.696 lbf/ in2 ⇔ 29.92 inHg * Density, \rho = 1.225 kg/m3 ⇔ 0.002377 slug/ft3 * Temperature, ''T'' = 15 °C ⇔ 288.15 K ⇔ 518.67 °R * Gas constant of air, ''R''air = 287.057 J/(kg·K) ⇔ 1716.59 ft·lb/sl·°R) * Specific Weight, \gamma = 12.014 N/ m3 ⇔ 0.07647 lbf/ ft3 * Dynamic viscosity, \mu = 1.789×10−5 Pa·s ⇔ 3.737×10−7 slug/(s·ft) * Acceleration of gravity, ''g0'' = 9.807 m/s2 ⇔ 32.174 ft/s2 See also * Sea level * Sea level rise Globally, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Pressure
Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, 760mm Hg, 29.9212 inchesHg, or 14.696psi.International Civil Aviation Organization. ''Manual of the ICAO Standard Atmosphere'', Doc 7488-CD, Third Edition, 1993. . The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth; that is, the Earth's atmospheric pressure at sea level is approximately 1 atm. In most circumstances, atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. As elevation increases, there is less overlying atmospheric mass, so atmospheric pressure decreases with increasing elevation. Because the atmosphere is thin relative to the Earth's radius—especially the dense atmospheric layer at low altitudes—the Earth's gravi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breathing Rate
The respiratory rate is the rate at which breathing occurs; it is set and controlled by the respiratory center of the brain. A person's respiratory rate is usually measured in breaths per minute. Measurement The respiratory rate in humans is measured by counting the number of breaths for one minute through counting how many times the chest rises. A fibre-optic breath rate sensor can be used for monitoring patients during a magnetic resonance imaging scan. Respiration rates may increase with fever, illness, or other medical conditions. Inaccuracies in respiratory measurement have been reported in the literature. One study compared respiratory rate counted using a 90-second count period, to a full minute, and found significant differences in the rates.. Another study found that rapid respiratory rates in babies, counted using a stethoscope, were 60–80% higher than those counted from beside the cot without the aid of the stethoscope. Similar results are seen with animals when t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal Metabolic Rate
Basal metabolic rate (BMR) is the rate of food energy, energy expenditure per unit time by endotherm, endothermic animals at rest. It is reported in energy units per unit time ranging from watt (joule/second) to ml O2/min or joule per hour per kg body mass J/(h·kg). Proper measurement requires a strict set of criteria to be met. These criteria include being in a physically and psychologically undisturbed state and being in a Thermal neutral zone, thermally neutral environment while in the post-absorptive state (i.e., not actively digesting food). In Bradymetabolism, bradymetabolic animals, such as fish and reptiles, the equivalent term standard metabolic rate (SMR) applies. It follows the same criteria as BMR, but requires the documentation of the temperature at which the metabolic rate was measured. This makes BMR a variant of standard metabolic rate measurement that excludes the temperature data, a practice that has led to problems in defining "standard" rates of metabolism for ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dive Profile
A dive profile is a description of a diver's pressure exposure over time. It may be as simple as just a depth and time pair, as in: "sixty for twenty," (a bottom time of 20 minutes at a depth of 60 feet) or as complex as a second by second graphical representation of depth and time recorded by a personal dive computer. Several common types of dive profile are specifically named, and these may be characteristic of the purpose of the dive. For example, a working dive at a limited location will often follow a constant depth (square) profile, and a recreational dive is likely to follow a multilevel profile, as the divers start deep and work their way up a reef to get the most out of the available breathing gas. The names are usually descriptive of the graphic appearance. The intended dive profile is useful as a planning tool as an indication of the risks of decompression sickness and oxygen toxicity for the exposure, to calculate a decompression schedule for the dive, and also fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decompression Status
The practice of decompression by divers comprises the planning and monitoring of the profile indicated by the algorithms or tables of the chosen decompression model, to allow asymptomatic and harmless release of excess inert gases dissolved in the tissues as a result of breathing at ambient pressures greater than surface atmospheric pressure, the equipment available and appropriate to the circumstances of the dive, and the procedures authorized for the equipment and profile to be used. There is a large range of options in all of these aspects. Decompression may be continuous or staged, where the ascent is interrupted by stops at regular depth intervals, but the entire ascent is part of the decompression, and ascent rate can be critical to harmless elimination of inert gas. What is commonly known as no-decompression diving, or more accurately no-stop decompression, relies on limiting ascent rate for avoidance of excessive bubble formation. Staged decompression may include deep s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decompression Computer
A dive computer, personal decompression computer or decompression meter is a device used by an underwater diver to measure the elapsed time and depth during a dive and use this data to calculate and display an ascent profile which according to the programmed decompression algorithm, will give a low risk of decompression sickness. Most dive computers use real-time ambient pressure input to a decompression algorithm to indicate the remaining time to the no-stop limit, and after that has passed, the minimum decompression required to surface with an acceptable risk of decompression sickness. Several algorithms have been used, and various personal conservatism factors may be available. Some dive computers allow for gas switching during the dive. Audible alarms may be available to warn the diver when exceeding the no-stop limit, the maximum operating depth for the gas mixture, the recommended ascent rate or other limit beyond which risk increases significantly. The display provides d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
