10-01-2021-0427 - cascading failure

A cascading failure is a process in a system of interconnected parts in which the failure of one or few parts can trigger the failure of other parts and so on. Such a failure may happen in many types of systems, including power transmission, computer networking, finance, transportation systems, organisms, the human body, and ecosystems.

Cascading failures may occur when one part of the system fails. When this happens, other parts must then compensate for the failed component. This in turn overloads these nodes, causing them to fail as well, prompting additional nodes to fail one after another.

Cascading structural failure[edit]

Certain load-bearing structures with discrete structural components can be subject to the "zipper effect", where the failure of a single structural member increases the load on adjacent members. In the case of the Hyatt Regency walkway collapse, a suspended walkway (which was already overstressed due to an error in construction) failed when a single vertical suspension rod failed, overloading the neighboring rods which failed sequentially (i.e. like a zipper). A bridge that can have such a failure is called fracture critical, and numerous bridge collapses have been caused by the failure of a single part. Properly designed structures use an adequate factor of safety and/or alternate load paths to prevent this type of mechanical cascade failure.^[5]

Other examples[edit]

Biology[edit]

Biochemical cascades exist in biology, where a small reaction can have system-wide implications. One negative example is ischemic cascade, in which a small ischemic attack releases toxins which kill off far more cells than the initial damage, resulting in more toxins being released. Current research is to find a way to block this cascade in stroke patients to minimize the damage.

In the study of extinction, sometimes the extinction of one species will cause many other extinctions to happen. Such a species is known as a keystone species.

Electronics[edit]

Another example is the Cockcroft–Walton generator, which can also experience cascade failures wherein one failed diode can result in all the diodes failing in a fraction of a second.

Yet another example of this effect in a scientific experiment was the implosion in 2001 of several thousand fragile glass photomultiplier tubes used in the Super-Kamiokande experiment, where the shock wave caused by the failure of a single detector appears to have triggered the implosion of the other detectors in a chain reaction.

Interdependent cascading failures[edit]

Fig. 1: Illustration of the interdependent relationship among different infrastructures

Fig. 2. Schematic demonstration of first- and second-order percolation transitions. In the second-order case, the giant component is continuously approaching zero at the percolation threshold p = . In the first-order case, the giant component approaches zero discontinuously

Diverse infrastructures such as water supply, transportation, fuel and power stations are coupled together and depend on each other for functioning, see Fig. 1. Owing to this coupling, interdependent networks are extremely sensitive to random failures, and in particular to targeted attacks, such that a failure of a small fraction of nodes in one network can trigger an iterative cascade of failures in several interdependent networks.^[12][13] Electrical blackouts frequently result from a cascade of failures between interdependent networks, and the problem has been dramatically exemplified by the several large-scale blackouts that have occurred in recent years. Blackouts are a fascinating demonstration of the important role played by the dependencies between networks. For example, the 2003 Italy blackout resulted in a widespread failure of the railway network, health care systems, and financial services and, in addition, severely influenced the telecommunication networks. The partial failure of the communication system in turn further impaired the electrical grid management system, thus producing a positive feedback on the power grid.^[14] This example emphasizes how inter-dependence can significantly magnify the damage in an interacting network system. A framework to study the cascading failures between coupled networks based on percolation theory was developed recently.^[15]The cascading failures can lead to abrupt collapse compare to percolation in a single network where the breakdown of the network is continuous, see Fig. 2. Cascading failures in spatially embedded systems have been shown to lead to extreme vulnerability.^[16] For the dynamic process of cascading failures see ref.^[17] A model for repairing failures in order to avoid cascading failures was developed by Di Muro et al.^[18]

Furthermore, it was shown that such interdependent systems when embedded in space are extremely vulnerable to localized attacks or failures. Above a critical radius of damage, the failure may spread to the entire system.^[19]

Cascading failures spreading of localized attacks on spatial multiplex networks with a community structure has been studied by Vaknin et al.^[20] Universal features of cascading failures in interdependent networks have been reported Duan et al.^[21] A method for mitigating cascading failures in networks using localized information has been developed by Smolyak et al.^[22]

For a comprehensive review on cascading failures in complex networks see Valdez et al.^[23]

Model for overload cascading failures[edit]

A model for cascading failures due to overload propagation is the Motter–Lai model.^[24] The tempo-spatial propagation of such failures have been studied by Jichang Zhao et al.^[25]

See also[edit]

• Blackouts
• Brittle system
• Butterfly effect
• Byzantine failure
• Cascading rollback
• Chain reaction
• Chaos theory
• Cache stampede
• Congestion collapse
• Domino effect
• For Want of a Nail (proverb)
• Network science
• Network theory
• Interdependent networks
• Kessler Syndrome
• Percolation theory
• Progressive collapse
• Virtuous circle and vicious circle
• Wicked problem

https://en.wikipedia.org/wiki/Cascading_failure

Wednesday, September 15, 2021

09-15-2021-0447 - homograph

context, homograph/homophone, communication, materials (dilution or concentration),draft, constants, tables, published literature, references, equations, programs, equipment, construction, surveyor, land, topology, soil, air, sol-gel, geography, geology, atmosphere, electric grid, positioning, adjacent facilities, pipelines, sewer, water, electric, nuclear grid, airforce, deep drilling, geooperations regional, rivers/mining/dams/etc., acoustics - tolerance vibration sonic sound subsonic (dams, caves, mines, refraction, rarefaction, reflection, absorption, etc.; foundation tolerance, post, cornerstone, center, arc-angle, arch, studs, anchors, tethers, etc.), nuclear warefare helium flashing (or geological), underground operations, classified operations, testing, malfunction, fracture, ageing, use, conditions, constraints, confounds, manuf/transport/storage, transport, assembly, audits, satellites/extraterresterial operations, space operations, asteriod/comet/volcano/flood/rain/snow/ice/sleet/hail/dust storm/tornado/cyclone/fire/etc., seasonal change, decade change, year change, weights and measures, observable, observer, interpreter/translation, interpretation, deformation, shear, stress, strain, warfaring/sabotage/infiltration/etc., etc..

comparison and contrast, verifications, second opinion, alternative diagnosis, analysis, etc..

in snow zone, seasonal change year general and specific trending change over decade or year, etc.. change in foundation with winter may not tolerate structure persistence at nuclear type reaction energy concentrated & mechanical components operated by human/computer/auto-trigger/etc. (human made). Ground freeze down, soften enthalpy transfer entropy increase dissipation of heat and transform occurrance. ice melt, burnt in time code on crystal of land (universe duration particle may inherent time code) v. imposed time code by nuclear energy operation etc. (designed/assembled by human/etc., etc.).

10-01-2021-0425 - catastrophic failure

 A catastrophic failure is a sudden and total failure from which recovery is impossible. Catastrophic failures often lead to cascading systems failure. The term is most commonly used for structural failures, but has often been extended to many other disciplines in which total and irrecoverable loss occurs, such as a head crash occurrence on a hard disk drive. Such failures are investigated using the methods of forensic engineering, which aims to isolate the cause or causes of failure.

For example, catastrophic failure can be observed in steam turbine rotor failure, which can occur due to peak stress on the rotor; stress concentration increases up to a point at which it is excessive, leading ultimately to the failure of the disc.

In firearms, catastrophic failure usually refers to a rupture or disintegration of the barrel or receiver of the gun when firing it. Some possible causes of this are an out-of-battery gun, an inadequate headspace, the use of incorrect ammunition, the use of ammunition with an incorrect propellant charge,^[1] a partially or fully obstructed barrel,^[2] or weakened metal in the barrel or receiver. A failure of this type, known colloquially as a "kaboom", or "kB" failure, can pose a threat not only to the user(s) but even many bystanders.

In chemical engineering, thermal runaway can cause catastrophic failure.

https://en.wikipedia.org/wiki/Catastrophic_failure

Tuesday, August 31, 2021

08-30-2021-2150 - Fungus Sepsis Total Organ Failure Illegal Organ Transplant

10-01-2021-0424 - Structural integrity and failure

 Structural integrity and failure is an aspect of engineering that deals with the ability of a structure to support a designed structural load (weight, force, etc.) without breaking and includes the study of past structural failures in order to prevent failures in future designs.

Structural integrity is the ability of an item—either a structural component or a structure consisting of many components—to hold together under a load, including its own weight, without breaking or deforming excessively. It assures that the construction will perform its designed function during reasonable use, for as long as its intended life span. Items are constructed with structural integrity to prevent catastrophic failure, which can result in injuries, severe damage, death, and/or monetary losses.

Structural failure refers to the loss of structural integrity, or the loss of load-carrying capacity in either a structural component or the structure itself. Structural failure is initiated when a material is stressed beyond its strength limit, causing fracture or excessive deformations; one limit state that must be accounted for in structural design is ultimate failure strength. In a well designed system, a localized failure should not cause immediate or even progressive collapse of the entire structure.

https://en.wikipedia.org/wiki/Structural_integrity_and_failure

10-01-2021-0421 - structural load or structural action

A structural load or structural action is a force, deformation, or acceleration applied to structural elements.^[1][2] A load causes stress, deformation, and displacement in a structure. Structural analysis, a discipline in engineering, analyzes the effects loads on structures and structural elements. Excess load may cause structural failure, so this should be considered and controlled during the design of a structure. Particular mechanical structures—such as aircraft, satellites, rockets, space stations, ships, and submarines—are subject to their own particular structural loads and actions.^[3] Engineers often evaluate structural loads based upon published regulations, contracts, or specifications. Accepted technical standards are used for acceptance testing and inspection.

https://en.wikipedia.org/wiki/Structural_load

Sunday, September 12, 2021

09-11-2021-2044 - Phosphonates and phosphonic acids

10-01-2021-0418 - Trisodium phosphate (TSP)

 Trisodium phosphate (TSP) is the inorganic compound with the chemical formula Na₃PO₄. It is a white, granular or crystalline solid, highly soluble in water, producing an alkaline solution. TSP is used as a cleaning agent, builder, lubricant, food additive, stain remover, and degreaser.^[7]

The item of commerce is often partially hydrated and may range from anhydrous Na₃PO₄ to the dodecahydrate Na₃PO₄ • 12H₂O. Most often found in white powder form, it can also be called trisodium orthophosphate or simply sodium phosphate.

https://en.wikipedia.org/wiki/Trisodium_phosphate