75 research outputs found
The effect of ice type on ice adhesion
To lower the ice adhesion strength is the most efficient technique for passive ice removal for several applications. In this paper, the effect of different types of ice on the ice adhesion strength was investigated. The ice types precipitation ice, in-cloud ice and bulk water ice on the same aluminum substrate and under similar environmental conditions were investigated. The ice adhesion strength was measured with a centrifugal adhesion test and varied from 0.78 ± 0.10 MPa for precipitation ice, 0.53 ± 0.12 MPa for in-cloud ice to 0.28 ± 0.08 MPa for bulk water ice. The results indicate that the ice adhesion strength inversely correlates with the density of ice. The results inspire a new strategy in icephobic surface development, specifically tailored to the relevant ice type
Presentations of computably enumerable reals
Abstract We study the relationship between a computably enumerable real and its presentations: ways of approximating the real by enumerating a prefix-free set of binary strings
Chronicles of Oklahoma
Article provides historical context to the recollections of Harry L. Finley, a "Sooner" pioneer who made the land run of 1893 to secure a section of land on the Cherokee Strip
Walking efficiency in children with cerebral palsy: relation to muscular strength and gait parameters
Effet de l'acide péracétique sur des bactéries en suspension et fixées
Les bonnes pratiques de la désinfection sont souvent mises en défaut par la présence d'agrégats de microorganismes et de biofilms fréquemment observés dans les environnements hydriques.
Aussi, les dĂ©sinfectants doivent ĂȘtre testĂ©s au laboratoire en utilisant des modĂšles bactĂ©riens rĂ©alistes et standardisĂ©s. A cet Ă©gard, afin d'Ă©valuer l'effet de l'acide peracĂ©tique (APA) vis Ă vis des bactĂ©ries, des eaux usĂ©es urbaines vĂ©hiculant de nombreux agrĂ©gats de microorganismes et des biofilms standards de laboratoire (formĂ©s avec des populations bactĂ©riennes mixtes autochtones) ont Ă©tĂ© utilisĂ©s dans cette Ă©tude.
Environ 99% des coliformes thermotolérants des eaux usées secondaires sont éliminés par ajout de 2,5 mg/l d'acide peracétique (temps de contact de 60 minutes à la température de 30°C). Un tel résultat est équivalent à celui obtenu par chloration mais la toxicité des effluents traités par APA (évaluée avec le test Microtox) est quasi nulle alors que celle des effluents chlorés est relativement élevée.
L'activitĂ© respiratoire des populations mixtes du biofilm formĂ© sur les parois du "rĂ©acteur-biofilm" est inhibĂ©e en prĂ©sence de 2,5 mg/l d'acide peracĂ©tique appliquĂ© pendant 30 minutes. Cependant l'arrachage d'une partie des cellules fixĂ©es (80%) n'est observĂ© que pour des traitements Ă plus forte concentration (30 mg/l d'acide peracĂ©tique/10 minutes). Un tel effet reste cependant limitĂ© car la rĂ©pĂ©tition journaliĂšre du traitement (30 mg APA/l/10 min) pendant 4 jours consĂ©cutifs ne permet pas d'Ă©liminer plus de 89% des cellules fixĂ©es. Aussi, une optimisation de tels traitements chocs doit ĂȘtre conduite Ă la seule fin d'Ă©liminer totalement le biofilm
Relative Enumerability in the Difference Hierarchy
We show that the intersection of the class of 2-REA degrees with that of the !-r.e. degrees consists precisely of the class of d.r.e. degrees. We also include some applications and show that there is no natural generalization of this result to higher levels of the REA hierarchy. 1 Introduction The \Delta 0 2 degrees of unsolvability are among the basic objects of study in classical recursion theory, since they are the degrees of those sets whose characteristic functions are limits of recursive functions. One of the means which recursion theorists use to get an understanding of the Turing degrees is the introduction of hierarchies to classify various kinds of complexity. The most natural such hierarchy, the arithmetical hierarchy, is itself not of much use in the classification of the \Delta 0 2 degrees, since it is far too coarse. This fact has led to the introduction of hierarchies based on finer distinctions than quantifier alternation. Two such hierarchies are by now well establi..
- âŠ