Effects of microstructure, temperature and R-ratio on fatigue crack propagation and threshold behaviour in two Ni-base alloys

Fatigue crack propagation and threshold data for two Ni-base alloys, Astroloy and Nimonic 901, are reported. At room temperature the effect which altering the load ratio (R-ratio) has on fatigue behaviour is strongly dependent on grain size. In the coarse grained microstructures crack growth rates increase and threshold values decrease markedly as R rises from 0. 1 to 0. 8, whereas only small changes in behaviour occur in fine grained material. In Astroloy, when strength level and gamma grain size are kept constant, there is very little effect of processing route and gamma prime distribution on room temperature threshold and crack propagation results. The dominant microstructural effect on this type of fatigue behaviour is the matrix ( gamma ) grain size itself.

Application of time series and Kalman filtering for structural health monitoring of a bridge

Peer reviewed

Soil Line and Simple Ratio

Resources created at the University of Southampton for the module Remote Sensing for Earth Observation

The designation of documentary types, series and units in Spain. A contribution to archival theory (2).

The identification of archival records depends on description, being this last process summed up in designation. The title given to dif-ferent groups of documents will have a great incidence in archival func-tions. Taking this premise as our starting point, this paper presents theo-retical contributions made in Spain related to designation of documen-tary types, series and units. The status of the issue presented here tries to delimitate the concept of “documentary typology”, essential for Ar-chival Science.

Classical Invariants for Principal Series and Isomorphisms of Root Data

We develop some new techniques to calculate the Schur indicator for self-dual irreducible Langlands quotients of the principal series representations. Using these techniques we derive some new formulas for the Schur indicator and the real-quaternionic indicator. We make progress towards developing an algorithm to decide whether or not two root data are isomorphic. When the derived group has cyclic center, we solve the isomorphism problem completely. An immediate consequence is a clean and precise classification theorem for connected complex reductive groups whose derived groups have cyclic center.

Is the consumption-income ratio stationary? Evidence from linear and nonlinear panel unit root tests for OECD and non-OECD countries

This paper applies recently developed heterogeneous nonlinear and linear panel unit root tests that account for cross-sectional dependence to 24 OECD and 33 non-OECD countries’ consumption-income ratios over the period 1951–2003. We apply a recently developed methodology that facilitates the use of panel tests to identify which individual cross-sectional units are stationary and which are nonstationary. This extends evidence provided in the recent literature to consider both linear and nonlinear adjustment in panel unit root tests, to address the issue of cross-sectional dependence, and to substantially expand both time-series and cross sectional dimensions of the data analysed. We find that the majority (65%) of the series are nonstationary with slightly fewer OECD countries’ (61%) series exhibiting a unit root than non-OECD countries (68%).

Band edge states of the < n >=0 gap of Fibonacci photonic lattices

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The duration of capture and restraint during anesthesia and euthanasia influences glucocorticoid levels in male golden hamsters

Deep litter has been shown to decrease stereotypic wire-gnawing in male golden hamsters, suggesting that increased litter depth may be associated with decreased chronic stress levels. To determine the relationship between litter depth and stress levels in hamsters, the authors measured serum levels of corticosterone, cortisol, and ACTH in male golden hamsters kept in cages with three different depths of litter. The duration of handling the hamsters significantly increased the concentrations of corticosterone, cortisol, and the ratio of cortisol/corticosterone. It took longer to catch hamsters housed in cages with deep litter and the ACTH levels were higher in these hamsters. The positive effect of the enrichment (deep litter) was diminished by methodological problems during handling/anesthesia.

Five-fold symmetry in crystalline quasicrystal lattices

To demonstrate that crystallographic methods can be applied to index and interpret diffraction patterns from well-ordered quasicrystals that display non-crystallographic 5-fold symmetry, we have characterized the properties of a series of periodic two-dimensional lattices built from pentagons, called Fibonacci pentilings, which resemble aperiodic Penrose tilings. The computed diffraction patterns from periodic pentilings with moderate size unit cells show decagonal symmetry and are virtually indistinguishable from that of the infinite aperiodic pentiling. We identify the vertices and centers of the pentagons forming the pentiling with the positions of transition metal atoms projected on the plane perpendicular to the decagonal axis of quasicrystals whose structure is related to crystalline η phase alloys. The characteristic length scale of the pentiling lattices, evident from the Patterson (autocorrelation) function, is ∼τ2 times the pentagon edge length, where τ is the golden ratio. Within this distance there are a finite number of local atomic motifs whose structure can be crystallographically refined against the experimentally measured diffraction data.

Sequências de Fibonacci e a Razão Áurea - aplicações no ensino básico

This thesis aims to present a study of the Fibonacci sequence, initiated from a simple problem of rabbits breeding and the Golden Ratio, which originated from a geometrical construction, for applications in basic education. The main idea of the thesis is to present historical records of the occurrence of these concepts in nature and science and their influence on social, cultural and scientific environments. Also, it will be presented the identification and the characterization of the basic properties of these concepts and howthe connection between them occurs,and mainly, their intriguing consequences. It is also shown some activities emphasizing geometric constructions, links to other mathematics areas, curiosities related to these concepts and the analysis of questions present in vestibular (SAT-Scholastic Aptitude Test) and Enem(national high school Exam) in order to show the importance of these themes in basic education, constituting an excellent opportunity to awaken the students to new points of view in the field of science and life, from the presented subject and to promote new ways of thinking mathematics as a transformative science of society.