hysteresis

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hysteresis

 [his-tĕ-re´sis]
1. the failure of coincidence of two associated phenomena, such as that exhibited in the differing temperatures of gelation and of liquefaction of a reversible colloid.
2. a phenomenon exhibited by a physical system in which the system's response to an outside influence depends not only on the instantaneous magnitude of the influence but also on the system's previous history, as when a material undergoing cyclical loading exhibits a loss of energy between cycles of loading and unloading.
3. in cardiac pacing terminology, the number of pulses per minute below the programmed pacing rate that the heart must drop in order to cause initiation of pacing; it can be programmed in by a pulse generator.

hys·ter·e·sis

(his'ter-ē'sis),
1. Failure of either one of two related phenomena to keep pace with the other; or any situation in which the value of one depends on whether the other has been increasing or decreasing.
2. The lag of a magnetic effect behind its cause. Synonym(s): magnetic inertia
3. The temperature differential that exists when a substance, such as reversible hydrocolloid, melts at one temperature and solidifies at another.
4. The basis of a type of cooperativity observed in many enzyme-catalyzed reactions in which the degree of cooperativity is associated with a slow conformational change of the enzyme. Compare: allosterism, cooperativity.
5. The nonlinear nature of the pressure-volume curve of the lung in which transpulmonary pressure at a given volume during inflation is less than the transpulmonary pressure at the same volume during exhalation.
[G. hysterēsis, a coming later]

hysteresis

/hys·te·re·sis/ (his″tĕ-re´sis) [Gr.]
1. a time lag in the occurrence of two associated phenomena, as between cause and effect.
2. in cardiac pacemaker terminology, the number of pulses per minute below the programmed pacing rate that the heart must drop in order to cause initiation of pacing.

hysteresis

[his′tərē′sis]
Etymology: Gk, hysterein, to be late
1 a lagging or retardation of one of two associated phenomena or a failure to act in unison.
2 the influence of the previous condition or treatment of the body on its subsequent response to a given force, as in the elastic property of a lung. At any given lung volume the elastic recoil pressure within the airways during expiration is less than that which exists at the same lung volume during inspiration.

hys·ter·e·sis

(his'tĕr-ē'sis)
1. Failure of either one of two related phenomena to keep pace with the other; or any situation in which the value of one depends on whether the other has been increasing or decreasing.
2. The lag of a magnetic effect behind its cause.
3. The temperature differential that exists when a substance melts at one temperature and solidifies at another.
4. A type of cooperativity in enzyme-catalyzed reactions in which the degree of cooperativity is associated with a slow conformational change of the enzyme.
Compare: allosterism
[G. hysterēsis, a coming later]

hys·ter·e·sis

(his'tĕr-ē'sis)
Failure of either one of two related phenomena to keep pace with the other; or any situation in which the value of one depends on whether the other has been increasing or decreasing.
[G. hysterēsis, a coming later]

hysteresis (histerē´sis),

n a physical phenomenon whereby a material such as a reversible hydrocolloid passes from a solid to a gel state at one temperature and a gel to a solid state at another.

hysteresis

the failure of coincidence of two associated phenomena, such as that exhibited in the differing temperatures of gelation and of liquefaction of a reversible colloid.
References in periodicals archive ?
A area da histerese reduziu 51% entre as temperaturas de 20 e 50 [grados]C.
O indice de histerese em relacao a dessorcao (IHRD) foi de 6,25% para 20 [grados]C e 3,03% para 50 [grados]C.
Histerese de isotermas de adsorcao e dessorcao de umidade de equilibrio para sementes de embauba.
Histerese encontrada para isoterma de sorcao de polpa de manga nas temperaturas estudadas Temperatura Area IHRD * ([grados]C) Dessorcao Adsorcao Histerese 20 0,138385 0,129738 0,00864777 0,0625 30 0,136326 0,127725 0,00748799 0,0549 40 0,137866 0,129299 0,00580839 0,0421 50 0,141237 0,132720 0,00427450 0,0303 * Indice de Histerese em Relacao a Dessorcao
Os principais fatores controladores do sentido do laco de histerese neste estudo foram as caracteristicas fisiograficas da bacia, a pequena area de drenagem e as caracteristicas das vertentes, que sao declivosas e curtas, a proximidade das fontes de sedimentos com a rede de drenagem e o tipo de uso e manejo do solo.
Os resultados mostram que para o grupo com volume maior que 40 mm o valor medio do indice de histerese foi de 3,12 e desvio padrao de 3,34 enquanto para o grupo de precipitacao menor que 40 mm a media foi de 3,31 e o desvio padrao de 0,68 caso em que a aplicacao da analise estatistica do tipo teste T de comparacao entre medias, mostra que a probabilidade de que as amostras dos dois grupos sejam da mesma populacao, e alta (91,90%), ou seja, nao ha evidencia estatistica de que as amostras dos dois grupos sejam diferentes estatisticamente.
Em relacao aos graficos da Figura 4 e a Tabela 1 e possivel fazer algumas inferencias sobre as diferencas na histerese entre os eventos, a partir das caracteristicas climaticas e de uso e manejo do solo:
Segundo Williams (1989), a ausencia de um grande suprimento de sedimentos e, normalmente, a principal causa da ocorrencia de efeito histerese de sentido horario em pequenas bacias.
Considera-se que o padrao do laco de histerese e governado pelos fatores acima mencionados, sendo que alguns deles (c e d) ainda sao objeto de analise.
A compreensao e a quantificacao da histerese podem ser uma importante ferramenta para a utilizacao de modelos matematicos de producao de sedimentos, sobretudo aqueles de escala de eventos como, por exemplo, Limburg Soil Erosion Model, haja vista que uma das principais dificuldades reside na discretizacao temporal do sedimentograma em conjunto com o hidrograma.
O padrao de forma de histerese entre a Q e CSS para a bacia em estudo e do tipo laco horario, independente do uso do solo, manejo do solo e precipitacao.
O indice quantitativo da histerese (IH) nos eventos dos dois periodos analisados apresentou um valor medio maior no periodo apos a implementacao de medidas de conservacao do solo; entretanto, os valores de IH apresentam uma dispersao significativa.