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Hardening Model (plasticity)
Hardening is the process by which something becomes harder or is made harder. Hardening may refer to: * Hardening (metallurgy), a process used to increase the hardness of a metal * Hardening (botany) or cold hardening, a process in which a plant undergoes physiological changes to mitigate damage from cold temperatures * Hardening (computing), the process of securing a system against attack * Target hardening, strengthening of the security of a building or installation to protect it from attack * Sclerotization, a biochemical process forming cuticle in arthropods See also * * Harden (other) Harden may refer to: Places * Harden, New South Wales, Australia ** Harden railway station **Harden County * Harden, Walsall, England * Harden, West Yorkshire, England * Harden City, Oklahoma, U.S. * Harden (crater), on the Moon Other uses * ... * Hardness, a measure of resistance to deformation {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardness
In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard metals such as titanium and beryllium are harder than soft metals such as sodium and metallic tin, or wood and common plastics. Macroscopic hardness is generally characterized by strong intermolecular bonds, but the behavior of solid materials under force is complex; therefore, hardness can be measured in different ways, such as scratch hardness, indentation hardness, and rebound hardness. Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity. Common examples of hard matter are ceramics, concrete, certain metals, and superhard materials, which can be contrasted with soft matter. Measuring hardness There are three main types of hardness measurements: ''scratch' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardening (metallurgy)
Hardening is a metallurgical metalworking process used to increase the hardness of a metal. The hardness of a metal is directly proportional to the uniaxial yield stress at the location of the imposed strain. A harder metal will have a higher resistance to plastic deformation than a less hard metal. Processes The five hardening processes are: *The Hall–Petch method, or grain boundary strengthening, is to obtain small grains. Smaller grains increases the likelihood of dislocations running into grain boundaries after shorter distances, which are very strong dislocation barriers. In general, smaller grain size will make the material harder. When the grain size approach sub-micron sizes, some materials may however become softer. This is simply an effect of another deformation mechanism that becomes easier, i.e. grain boundary sliding. At this point, all dislocation related hardening mechanisms become irrelevant. *In work hardening (also referred to as strain hardening) the materi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardening (botany)
Cold hardening is the physiological and biochemical process by which an organism prepares for cold weather. Plants Plants in temperate and polar regions adapt to winter and sub zero temperatures by relocating nutrients from leaves and shoots to storage organs. Freezing temperatures induce dehydrative stress on plants, as water absorption in the root and water transport in the plant decreases. Water in and between cells in the plant freezes and expands, causing tissue damage. Cold hardening is a process in which a plant undergoes physiological changes to avoid, or mitigate cellular injuries caused by sub-zero temperatures. Non-acclimatized individuals can survive −5 °C, while an acclimatized individual in the same species can survive −30°C. Plants that originated in the tropics, like tomato or maize, don't go through cold hardening and are unable to survive freezing temperatures. The plant starts the adaptation by exposure to cold yet still not freezing temperatures. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardening (computing)
In computer security, hardening is usually the process of securing a system by reducing its surface of vulnerability, which is larger when a system performs more functions; in principle a single-function system is more secure than a multipurpose one. Reducing available ways of attack typically includes changing default passwords, the removal of unnecessary software, unnecessary usernames or logins, and the disabling or removal of unnecessary services. There are various methods of hardening Unix and Linux systems. This may involve, among other measures, applying a patch to the kernel such as Exec Shield or PaX; closing open network ports; and setting up intrusion-detection systems, firewalls and intrusion-prevention systems. There are also hardening scripts and tools like Lynis, Bastille Linux, JASS for Solaris systems and Apache/PHP Hardener that can, for example, deactivate unneeded features in configuration files or perform various other protective measures. Bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Target Hardening
Target hardening, also referred to simply as hardening when made clear by the context, is a term used by police officers, those working in security, and the military referring to the strengthening of the security of a building or installation in order to protect it in the event of attack or reduce the risk of theft. It is believed that a "strong, visible defense will deter or delay an attack". In terms of business and home security, target hardening is one of the suite of protective measures that are included in crime prevention through environmental design. This can include ensuring all doors and windows are sourced and fitted in such a way that they can resist forcible and surreptitious intruder attack, adding hard barriers and landscapes that resist vehicle and pedestrian intrusion, adding fences, walls and hostile planting. All of these are greatly assisted by removing or pruning any trees or bushes that could offer suitable hiding places or could be used to climb to a higher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sclerotization
Sclerotization is a biochemical process that produces the rigid shell of sclerotin that comprises an insect's chitinous exoskeleton. It is prominent in the thicker, armored parts of insects and arachnids, especially in the biting mouthparts and sclerites of scorpions and beetles. Molecular mechanism Sclerotization entails crosslinking of oxygen-reactive derivatives of dopamine. The reaction of the dopamine derivatives toward oxygen is catalyzed by diverse enzymes such as laccase, which convert the catechol groups to quinones. The resulting quinones are susceptible to nucleophilic attack by amines and thiols, which decorate the side-chains of proteins. These reactions gives rise to color (typically brown), loss of solubility, and rigidification that accompany sclerotization.{{cite journal , doi=10.1007/s00726-005-0298-2, title=When Quinones Meet Amino Acids: Chemical, Physical and Biological Consequences, year=2006, last1=Bittner, first1=S., journal=Amino Acids, volume=30, issue=3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harden (other)
Harden may refer to: Places * Harden, New South Wales, Australia ** Harden railway station **Harden County * Harden, Walsall, England * Harden, West Yorkshire, England * Harden City, Oklahoma, U.S. * Harden (crater), on the Moon Other uses * "Harden", a song by Lil Wayne from the album ''Funeral'' * Hardens, historic home and farm in Charles City County, Virginia, U.S. * Harden's, a British restaurant guide * Harden Furniture, an American furniture manufacturer 1844–2018 People with the given name Harden * Harden Askenasy (1908–1975), Romanian Jewish scientist and professor of neurosurgery *Harden Bennion (1862–1936), American politician *Harden Cooper (1922–1990), American football player and coach *Harden Dean (1913–1982), Australian rules footballer *Harden M. McConnell (1927–2014), American chemist *Harden Sidney Melville (1821–1894), English painter, illustrator and draughtsman People with the surname Harden * Alex Harden (born 1993), American basketbal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
