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Scrubber Endurance
A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantial 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, while also eliminating the bubbles otherwise produced by an open circuit system. The latter advantage over other systems is useful for covert military operations by frogmen, as well as for undisturbed observation of underwater wildlife. A rebreather is generally understood to be a portable apparatus 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 i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AP Diving
AP Diving or Ambient Pressure Diving, formerly known as A.P.Valves, is a British manufacturer of diving equipment at Water-Ma-Trout in Helston, Cornwall, England. They produce a range of scuba and surface-supplied diving equipment including buoyancy compensator jackets and the Inspiration range of electronically controlled closed circuit diving rebreathers. 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' 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 It has been superseded by more recent models using different electro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extra-vehicular Activity
Extravehicular activity (EVA) is any activity done by an astronaut in outer space outside a spacecraft. In the absence of a breathable Earthlike atmosphere, the astronaut is completely reliant on a space suit for environmental support. EVA includes spacewalks and lunar or planetary surface exploration (commonly known from 1969 to 1972 as moonwalks). In a stand-up EVA (SEVA), an astronaut stands through an open hatch but does not fully leave the spacecraft. EVAs have been conducted by the Soviet Union/Russia, the United States, Canada, the European Space Agency and China. On March 18, 1965, Alexei Leonov became the first human to perform a spacewalk, exiting the Voskhod 2 capsule for 12 minutes and 9 seconds. On July 20, 1969, Neil Armstrong became the first human to perform a moonwalk, outside his lunar lander on Apollo 11 for 2 hours and 31 minutes. In 1984, Svetlana Savitskaya became the first woman to perform a spacewalk, conducting EVA outside the Salyut 7 space stati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boyle's Law
Boyle's law, also referred to as the Boyle–Mariotte law or Mariotte's law (especially in France), is an empirical gas laws, gas law that describes the relationship between pressure and volume of a confined gas. Boyle's law has been stated as: The absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of substance, amount of gas remain unchanged within a closed system.Levine (1978) p. 12 gives the original definition. Mathematically, Boyle's law can be stated as: or where is the pressure of the gas, is the volume of the gas, and is a Constant (mathematics), constant for a particular temperature and amount of gas. Boyle's law states that when the temperature of a given mass of confined gas is constant, the product of its pressure and volume is also constant. When comparing the same substance under two different sets of conditions, the law can be expressed as: P_1 V_1 = P_2 V_2. showi ... [...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 Underwater diving, as a human activity, is the practice of descending below the water's surface to interact with the environment. It is also often referred to as diving (other), diving, an ambiguous term with several possible meani .... 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 – 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, ... [...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 ⇔ 760 mmHg ⇔ 29.92 inHg * Density, \rho = 1.225 kg/m3 ⇔ 0.002377 slug/ft3 * Temperature, ''T'' = 15 °C ⇔ 59 °F ⇔ 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 * Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Pressure
Atmospheric pressure, also known as air pressure or 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 1,013.25 millibars, 760 mm Hg, 29.9212 inchesHg, or 14.696 psi.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 altitu ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal Metabolic Rate
Basal metabolic rate (BMR) is the rate of energy expenditure per unit time by endothermic animals at rest.. In other words it is the energy required by body organs to perform normal 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 thermally neutral environment while in the post- absorptive state (i.e., not actively digesting food). In 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 o ... [...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 Professional diving, working dive at a limited location will often follow a constant depth (square) profile, and a Recreational diving, 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 Dive planning, planning tool as an indication of the risks of decompression sickness and oxygen toxicity for the exposure, to calcul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decompression Status
To prevent or minimize decompression sickness, Underwater diving, divers must properly plan and monitor Decompression (diving), decompression. Divers follow a decompression model to safely allow the release of excess inert gases dissolved in their body tissues, which accumulated as a result of breathing at ambient pressures greater than surface atmospheric pressure. Decompression models take into account variables such as depth and time of dive, breathing gasses, altitude, and equipment to develop appropriate procedures for safe ascent. 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 stops de ... [...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. A secondary function is to record the dive profile, warn the diver when certain events occur, and provide useful information about the environment. Dive computers are a development from decompression tables, the diver's watch and depth gauge, with greater accuracy and the ability to monitor dive profile data in real time. 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 fact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Control System
A control system manages, commands, directs, or regulates the behavior of other devices or systems using control loops. It can range from a single home heating controller using a thermostat controlling a domestic boiler to large industrial control systems which are used for controlling processes or machines. The control systems are designed via control engineering process. For continuously modulated control, a feedback controller is used to automatically control a process or operation. The control system compares the value or status of the process variable (PV) being controlled with the desired value or setpoint (SP), and applies the difference as a control signal to bring the process variable output of the plant to the same value as the setpoint. For sequential and combinational logic, software logic, such as in a programmable logic controller, is used. Open-loop and closed-loop control Feedback control systems Logic control Logic control systems for indus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
