Tribonucleation

	Tribonucleation Tribonucleation is a mechanism that creates small gas bubbles by the action of making and breaking contact between solid surfaces immersed in a liquid containing dissolved gas. These small bubbles may then act as nuclei for the growth of bubbles when the pressure is reduced. As the formation of the nuclei occurs quite easily, the effect may occur in a human body engaged in light exercise, yet produce no symptoms. However tribonucleation may be a source of growing bubbles affecting scuba divers when ascending to the surface and is a potential cause of decompression sickness. The process has also been described as the basis for the cracking sound produced by the manipulation of human synovial joints. References {{reflist , refs= {{cite journal , last1= Hugon , first1= J. , last2= Barthelemy , first2= L. , last3= Rostain , first3= J.C. , last4= Gardette , first4= B. , title=The pathway to drive decompression microbubbles from the tissues to the blood and the lymphatic syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Decompression Sickness Decompression sickness (abbreviated DCS; also called divers' disease, the bends, aerobullosis, and caisson disease) is a medical condition caused by dissolved gases emerging from solution as bubbles inside the body tissues during decompression. DCS most commonly occurs during or soon after a decompression ascent from underwater diving, but can also result from other causes of depressurisation, such as emerging from a caisson, decompression from saturation, flying in an unpressurised aircraft at high altitude, and extravehicular activity from spacecraft. DCS and arterial gas embolism are collectively referred to as decompression illness. Since bubbles can form in or migrate to any part of the body, DCS can produce many symptoms, and its effects may vary from joint pain and rashes to paralysis and death. DCS often causes air bubbles to settle in major joints like knees or elbows, causing individuals to bend over in excruciating pain, hence its common name, the bends. Indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Cracking Joints Joint cracking is the manipulation of joints to produce a sound and related "popping" sensation. It is sometimes performed by physical therapists, chiropractors, osteopaths, and masseurs in Turkish baths pursuing a variety of outcomes. The cracking of joints, especially knuckles, was long believed to lead to arthritis and other joint problems. However, this is not supported by medical research. The cracking mechanism and the resulting sound is caused by dissolved gas (nitrogen gas) cavitation bubbles suddenly collapsing inside the joints. This happens when the joint cavity is stretched beyond its normal size. The pressure inside the joint cavity drops and the dissolved gas suddenly comes out of solution and takes gaseous form which makes a distinct popping noise. To be able to crack the same knuckle again requires waiting about 15 minutes before the bubbles dissolve back into the synovial fluid and will be able to form again. It is possible for voluntary joint cracking by an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Nucleation In thermodynamics, nucleation is the first step in the formation of either a new thermodynamic phase or structure via self-assembly or self-organization within a substance or mixture. Nucleation is typically defined to be the process that determines how long an observer has to wait before the new phase or self-organized structure appears. For example, if a volume of water is cooled (at atmospheric pressure) below 0°C, it will tend to freeze into ice, but volumes of water cooled only a few degrees below 0°C often stay completely free of ice for long periods ( supercooling). At these conditions, nucleation of ice is either slow or does not occur at all. However, at lower temperatures nucleation is fast, and ice crystals appear after little or no delay. Nucleation is a common mechanism which generates first-order phase transitions, and it is the start of the process of forming a new thermodynamic phase. In contrast, new phases at continuous phase transitions start to form imm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Scuba Diver Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply. The name "scuba", an acronym for " Self-Contained Underwater Breathing Apparatus", was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long and/or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the likelihood and effects of nitrogen narcosis during deeper dives. Open circuit scuba systems discharge the breathing gas into the environment as it is exhaled, and consist of one or more diving cylinders containing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Undersea And Hyperbaric Medical Society The underwater environment is the region below the surface of, and immersed in, liquid water in a natural or artificial feature (called a body of water), such as an ocean, sea, lake, pond, reservoir, river, canal, or aquifer. Some characteristics of the underwater environment are universal, but many depend on the local situation. Liquid water has been present on Earth for most of the history of the planet. The underwater environment is thought to be the place of the origin of life on Earth, and it remains the ecological region most critical to the support of life and the natural habitat of the majority of living organisms. Several branches of science are dedicated to the study of this environment or specific parts or aspects of it. A number of human activities are conducted in the more accessible parts of the underwater environment. These include research, underwater diving for work or recreation, and underwater warfare with submarines. It is hostile to humans in many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Mechanisms (engineering) Mechanism may refer to: * Mechanism (engineering), rigid bodies connected by joints in order to accomplish a desired force and/or motion transmission Mechanism (biology), explaining how a feature is created Mechanism (philosophy), a theory that all natural phenomena can be explained by physical causes * Mechanism (sociology), a theory that all social phenomena can be explained by the existence of a deterministic mechanism * " The Mechanism", song by Disclosure * ''The Mechanism'' (TV series), a Netflix TV series See also * Machine Machine (mechanical) Linkage (mechanical) Mechanism design, the art of designing rules of a game to achieve a specific outcome Mechanism of action, the means by which a drug exerts its biological effects Defence mechanism, unconscious mechanisms aimed at reducing anxiety Reaction mechanism, the sequence of reactions by which overall chemical change occurs Antikythera mechanism, an ancient Greek analog computer Theory of operation A theory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Underwater Diving Physiology Human physiology of underwater diving is the physiological influences of the underwater environment on the human diver, and adaptations to operating underwater, both during breath-hold dives and while breathing at ambient pressure from a suitable breathing gas supply. It, therefore, includes the range of physiological effects generally limited to human ambient pressure divers either freediving or using underwater breathing apparatus. Several factors influence the diver, including immersion, exposure to the water, the limitations of breath-hold endurance, variations in ambient pressure, the effects of breathing gases at raised ambient pressure, effects caused by the use of breathing apparatus, and sensory impairment. All of these may affect diver performance and safety. Immersion affects fluid balance, circulation and work of breathing. Exposure to cold water can result in the harmful cold shock response, the helpful diving reflex and excessive loss of body heat. Breath-hold durat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]