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Task Loading
A task load indicates the degree of difficulty experienced when performing a task, and task loading describes the accumulation of tasks that are necessary to perform an operation. A light task loading can be managed by the operator with capacity to spare in case of contingencies. Task loads are primarily associated with underwater diving. They are also associated with workloads in other environments, such as aircraft cockpits and command and control stations. Task loads may be measured and compared. NASA uses six sub-scales in their task load rating procedure. Three of these relate to the demands on the subject and the other three to interactions between subject and task. Ratings contain a large personal component and may vary considerably between subjects, and over time as experience is gained. #Mental Demands: How much mental and perceptual effort is required; #Physical Demands: How much physical effort is required; #Temporal Demands: How much time pressure the subject feels; #O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 meanings, depending on context. Immersion in water and exposure to high ambient pressure have Physiology, physiological effects that limit the depths and duration possible in ambient pressure diving. Humans are not physiologically and anatomically well-adapted to the environmental conditions of diving, and various equipment has been developed to extend the depth and duration of human dives, and allow different types of work to be done. In ambient pressure diving, the diver is directly exposed to the pressure of the surrounding water. The ambient pressure diver may dive on breath-hold (freediving) or use breathing apparatus for scuba diving or surface-supplied diving, and the saturation diving technique reduces the risk of decompression sickness ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diver Propulsion Vehicle
A diver propulsion vehicle (DPV), also known as an underwater propulsion vehicle, sea scooter, underwater scooter, or swimmer delivery vehicle (SDV) by armed forces, is an item of diving equipment used by scuba divers to increase range underwater. Range is restricted by the amount of breathing gas that can be carried, the rate at which that breathing gas is consumed, and the battery power of the DPV. Time limits imposed on the diver by decompression requirements may also limit safe range in practice. DPVs have recreational, scientific and military applications. DPVs include a range of configurations from small, easily portable scooter units with a small range and low speed, to faired or enclosed units capable of carrying several divers longer distances at higher speeds. The earliest recorded DPVs were used for military purposes during World War II and were based on torpedo technology and components. Structure A DPV usually consists of a pressure-resistant watertight casing c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overlearning
Overlearning refers to practicing newly acquired skills beyond the point of initial mastery. The term is also often used to refer to the pedagogical theory that this form of practice leads to automaticity or other beneficial consequences. Early studies Memory researcher Hermann Ebbinghaus performed classical overlearning studies in the late 1890s. He noticed that memory for learned material decreased over time (see also forgetting curve). Ebbinghaus recognized that lists of nonsense syllables became more difficult to recall over time, and some lists required more review time to regain 100% recall. He defined overlearning as the number of repetitions of material after which it can be recalled with 100% accuracy. Contemporary work A 1992 meta-analysis suggested that overlearning does significantly affect recall over time. It also concluded that the size of this effect may be moderated by the amount of overlearning, task type, and length of retention. The meta-analysis included ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diving Hazards And Precautions
Divers face specific physical and health Health has a variety of definitions, which have been used for different purposes over time. In general, it refers to physical and emotional well-being, especially that associated with normal functioning of the human body, absent of disease, p ... risks when they go underwater with scuba or other diving equipment, or use high pressure breathing gas. Some of these factors also affect people who work in raised pressure environments out of water, for example in caissons. This article lists hazards that a diver may be exposed to during a dive, and possible consequences of these hazards, with some details of the proximate causes of the listed consequences. A listing is also given of precautions that may be taken to reduce vulnerability, either by reducing the risk or mitigating the consequences. A hazard that is understood and acknowledged may present a lower risk if appropriate precautions are taken, and the consequences may be less s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diving Safety
Diving safety is the aspect of underwater diving operations and activities concerned with the safety of the participants. The safety of underwater diving depends on four factors: the environment, the equipment, behaviour of the individual diver and performance of the dive team. The underwater environment can impose severe physical and psychological stress on a diver, and is mostly beyond the diver's control. Equipment is used to operate underwater for anything beyond very short periods, and the reliable function of some of the equipment is critical to even short-term survival. Other equipment allows the diver to operate in relative comfort and efficiency, or to remain healthy over the longer term. The performance of the individual diver depends on learned skills, many of which are not intuitive, and the performance of the team depends on competence, communication, attention and common goals. There is a List of diving hazards and precautions, large range of hazards to which the dive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penetration Diving
An overhead or penetration diving environment is where the diver enters a space from which there is no direct, purely vertical ascent to the safety of breathable atmosphere at the surface. Cave diving, wreck diving, ice diving and diving inside or under other natural or artificial underwater structures or enclosures are examples. The restriction on direct ascent increases the risk of diving under an overhead, and this is usually addressed by adaptations of procedures and use of equipment such as redundant breathing gas sources and guide lines to indicate the route to the exit. There are some applications where scuba diving is appropriate and surface-supplied diving is not, and other where the converse is true. In other applications either may be appropriate, and the mode is chosen to suit the specific circumstances. In all cases risk is managed by appropriate planning, skills, training and choice of equipment. Environments Penetration diving is also known as diving in overhe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guideline
A guideline is a statement by which to determine a course of action. It aims to streamline particular processes according to a set routine or sound practice. They may be issued by and used by any organization (governmental or private) to make the actions of its employees or divisions more predictable, and presumably of higher quality. A guideline is similar to a rule, but are legally less binding as justified deviations are possible. List of guidelines Examples of guidelines are: * Code of practice * EASE Guidelines for Authors and Translators of Scientific Articles * Federal Sentencing Guidelines * Guidelines for Examination in the European Patent Office * Medical guidelines * Publicly Available Specification A Publicly Available Specification or PAS is a standardization document that closely resembles a formal standard in structure and format but which has a different development model. The objective of a Publicly Available Specification is to speed up ... * Programmi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rebreather
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 supp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decompression (diving)
The decompression of a diver is the reduction in ambient pressure experienced during ascent from depth. It is also the process of elimination of dissolved inert gases from the diver's body which accumulate during ascent, largely during pauses in the ascent known as decompression stops, and after surfacing, until the gas concentrations reach equilibrium. Divers breathing gas at ambient pressure need to ascend at a rate determined by their exposure to pressure and the breathing gas in use. A diver who only breathes gas at atmospheric pressure when free-diving or snorkelling will not usually need to decompress. Divers using an atmospheric diving suit do not need to decompress as they are never exposed to high ambient pressure. When a diver descends in the water, the hydrostatic pressure, and therefore the ambient pressure, rises. Because breathing gas is supplied at ambient pressure, some of this gas dissolves into the diver's blood and is transferred by the blood to ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
No Decompression Limit
To prevent or minimize decompression sickness, divers must properly plan and monitor 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 depending on the theoretical model used fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scuba Diving
Scuba diving is a Diving mode, mode of underwater diving whereby divers use Scuba set, breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The word ''scuba'' is an Acronym#Normal case and acronyms, acronym for "Self-Contained Underwater Breathing Apparatus" and was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, affording them greater independence and movement than surface-supplied divers, and more time underwater than freedivers. Although the use of compressed air is common, other gas blends are also used. Open-circuit scuba systems discharge the breathing gas into the environment as it is exhaled and consist of one or more diving cylinders containing breathing gas at high pressure which is supplied to the diver at ambient pressure through a diving regulator. They may include additional cylinders for range extension, de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buddy Diving
Buddy diving is the use of the buddy system by scuba divers and freedivers. It is a set of safety procedures intended to improve the chances of avoiding or surviving accidents in or under water by having divers dive in a group of two or sometimes three. When using the buddy system, members of the group dive together and co-operate with each other, so that they can help or rescue each other in the event of an emergency. This is most effective if both divers are competent in all relevant skills and sufficiently aware of the situation that they can respond in time, which is a matter of both attitude and competence. In recreational diving, a pair of divers is usually considered best for buddy diving. With threesomes, one diver can easily lose the attention of the other two, and groups of more than three divers are not using the buddy system. The system is likely to be effective in mitigating out-of-air emergencies, non-diving medical emergencies and entrapment in ropes or nets. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
