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Regulator Icing
Ice diving is a type of penetration diving where the dive takes place under ice. Because diving under ice places the diver in an overhead environment typically with only a single entry/exit point, it requires special procedures and equipment. Ice diving is done for purposes of recreation, scientific research, public safety (usually search and rescue/recovery) and other professional or commercial reasons. The most obvious hazards of ice diving are getting lost under the ice, hypothermia, and regulator failure due to freezing. Scuba divers are generally tethered for safety. This means that the diver wears a harness to which a line is secured, and the other end of the line is secured above the surface and monitored by an attendant. Surface supplied equipment inherently provides a tether, and reduces the risks of regulator first stage freezing as the first stage can be managed by the surface team, and the breathing gas supply is less limited. For the surface support team, the h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refrigeration
Refrigeration is any of various types of cooling of a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is ejected to a place of higher temperature).IIR International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.php ASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/ashrae-terminology Refrigeration is an artificial, or human-made, cooling method. Refrigeration refers to the process by which energy, in the form of heat, is removed from a low-temperature medium and transferred to a high-temperature medium. This work of energy transfer is traditionally driven by work (physics), mechanical means (whether ice or electromechanics, electromechanical machines), but it can also be driven by heat, magnetism, electricity, laser cooling, laser, or other means. Refrigeration has many applications, including household refrigerators, industrial freezers, cryogenics, and air conditioni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diving Supervisor
The diving supervisor is the professional diving team member who is directly responsible for the diving operation's safety and the management of any incidents or accidents that may occur during the operation; the supervisor is required to be available at the control point of the diving operation for the diving operation's duration, and to manage the planned dive and any contingencies that may occur. Details of competence, requirements, qualifications, registration and formal appointment differ depending on jurisdiction and relevant codes of practice. Diving supervisors are used in commercial diving, military diving, public safety diving and scientific diving operations. The control point is the place where the supervisor can best monitor the status of the diver and progress of the dive. For scuba dives this is commonly on deck of the dive boat where there is a good view of the surface above the operational area, or on the shore at a nearby point where the divers can be seen whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diver Communications
Diver communications are the methods used by Underwater diving, divers to communicate with each other or with surface members of the dive team. In professional diving, diver communication is usually between a single working diver and the diving supervisor at the surface control point. This is considered important both for managing the diving work, and as a safety measure for monitoring the condition of the diver. The traditional method of communication was by line signals, but this has been superseded by voice communication, and line signals are now used in emergencies when voice communications have failed. Surface supplied divers often carry a closed circuit video camera on the diving helmet, helmet which allows the surface team to see what the diver is doing and to be involved in inspection tasks. This can also be used to transmit hand signals to the surface if voice communications fails. Underwater slates may be used to write text messages which can be shown to other divers, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technical Diving
Technical diving (also referred to as tec diving or tech diving) is scuba diving that exceeds the List of diver certification organizations, agency-specified limits of recreational diving for non-Professional diver, professional purposes. Technical diving may expose the diver to hazards beyond those normally associated with recreational diving, and to a greater risk of serious injury or death. Risk may be reduced by using suitable equipment and procedures, which require appropriate knowledge and skills. The required knowledge and skills are preferably developed through specialised training, adequate practice, and experience. The equipment involves breathing gases other than air or standard nitrox mixtures, and multiple gas sources. Most technical diving is done within the limits of training and previous experience, but by its nature, technical diving includes diving which pushes the boundaries of recognised safe practice, and new equipment and procedures are developed and honed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Diving Site
Ice is water that is frozen into a solid state, typically forming at or below temperatures of 0 ° C, 32 ° F, or 273.15 K. It occurs naturally on Earth, on other planets, in Oort cloud objects, and as interstellar ice. As a naturally occurring crystalline inorganic solid with an ordered structure, ice is considered to be a mineral. Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-white color. Virtually all of the ice on Earth is of a hexagonal crystalline structure denoted as ''ice Ih'' (spoken as "ice one h"). Depending on temperature and pressure, at least nineteen phases ( packing geometries) can exist. The most common phase transition to ice Ih occurs when liquid water is cooled below (, ) at standard atmospheric pressure. When water is cooled rapidly (quenching), up to three types of amorphous ice can form. Interstellar ice is overwhelmingly low-density amorphous ice (LDA), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buoyancy Compensator (diving)
Buoyancy (), or upthrust, is the force exerted by a fluid opposing the weight of a partially or fully immersed object (which may be also be a parcel of fluid). In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus, the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. The pressure difference results in a net upward force on the object. The magnitude of the force is proportional to the pressure difference, and (as explained by Archimedes' principle) is equivalent to the weight of the fluid that would otherwise occupy the submerged volume of the object, i.e. the displaced fluid. For this reason, an object with average density greater than the surrounding fluid tends to sink because its weight is greater than the weight of the fluid it displaces. If the object is less dense, buo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Mass
In building design, thermal mass is a property of the matter of a building that requires a flow of heat in order for it to change temperature. Not all writers agree on what physical property of matter "thermal mass" describes. Most writers use it as a synonym for heat capacity, the ability of a body to store thermal energy. It is typically referred to by the symbol ''C''th, and its SI unit is J/K or J/°C (which are equivalent). However: * Christoph Reinhart at MIT describes thermal mass as its volume times its volumetric heat capacity. * Randa Ghattas, Franz-Joseph Ulm and Alison Ledwith, also at MIT, write that "It hermal massis dependent on the relationship between the specific heat capacity, density, thickness and conductivity of a material" although they don't provide a unit, describing materials only as "low" or "high" thermal mass. * Chris Reardon equates thermal mass with volumetric heat capacity . The lack of a consistent definition of what property of matter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quality Assurance
Quality assurance (QA) is the term used in both manufacturing and service industries to describe the systematic efforts taken to assure that the product(s) delivered to customer(s) meet with the contractual and other agreed upon performance, design, reliability, and maintainability expectations of that customer. The core purpose of Quality Assurance is to prevent mistakes and defects in the development and production of both manufactured products, such as automobiles and shoes, and delivered services, such as automotive repair and athletic shoe design. Assuring quality and therefore avoiding problems and delays when delivering products or services to customers is what ISO 9000 defines as that "part of quality management focused on providing confidence that quality requirements will be fulfilled". This defect prevention aspect of quality assurance differs from the defect detection aspect of quality control and has been referred to as a ''shift left'' since it focuses on quality effor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
