945 resultados para Building, Iron and steel Testing
Resumo:
This paper explores the nature of community capacity-building in the context of local development. It challenges some of the simplistic constructions of community as a distinctive stakeholder with a shared set of values and clear identity. Even in apparently homogeneous place-based communities such as in the Catholic Ardoyne area of North Belfast there are important differences in the way in which local people interact with the organised voluntary sector. The paper concludes by highlighting the need to reach deeper into the concerns of local people, rather than the priorities of statutory funders, as a basis for service provision and local planning.
Resumo:
In two experiments, we tested some of the central claims of the empathizing-systemizing (E-S) theory. Experiment 1 showed that the systemizing quotient (SQ) was unrelated to performance on a mathematics test, although it was correlated with statistics-related attitudes, self-efficacy, and anxiety. In Experiment 2, systemizing skills, and gender differences in these skills, were more strongly related to spatial thinking styles than to SQ. In fact, when we partialled the effect of spatial thinking styles, SQ was no longer related to systemizing skills. Additionally, there was no relationship between the Autism Spectrum Quotient (AQ) and the SQ, or skills and interest in mathematics and mechanical reasoning. We discuss the implications of our findings for the E-S theory, and for understanding the autistic cognitive profile.
Resumo:
Fiber-reinforced polymer (FRP) hollow tubes are used in structural applications, such as utility poles and pipelines. Concrete-filled FRP tubes (CFFTs) are also used as piles and bridge piers. Applications such as poles and marine piles are typically governed by cyclic bending. In this paper, the fatigue behavior of glass-FRP filament-wound tubes is studied using coupons cut from the tubes. Several coupon configurations were first examined in 24 tension and five compression monotonic loading tests. Fatigue tests were then conducted on 81 coupons to examine several parameters; namely, loading frequency as well as maximum-to-ultimate (max ult) and minimum-to-maximum (min max) stress ratios, including tension tension and tension compression, to simulate reversed bending. The study demonstrated the sensitivity of test results and failure mode to coupon configuration. The presence of compression loads reduced fatigue life, while increasing load frequency increased fatigue life. Stiffness degradation behavior was also established. To achieve at least one million cycles, it is recommended to limit (max ult) to 0.25. Models were used to simulate stiffness degradation and fatigue life curve of the tube. Fatigue life predictions of large CFFT beams showed good correlation with experimental results. © 2008 ASCE.
Resumo:
Invasion ecology urgently requires predictive methodologies that can forecast the ecological impacts of existing, emerging and potential invasive species. We argue that many ecologically damaging invaders are characterised by their more efficient use of resources. Consequently, comparison of the classical ‘functional response’ (relationship between resource use and availability) between invasive and trophically analogous native species may allow prediction of invader ecological impact. We review the utility of species trait comparisons and the history and context of the use of functional responses in invasion ecology, then present our framework for the use of comparative functional responses. We show that functional response analyses, by describing the resource use of species over a range of resource availabilities, avoids many pitfalls of ‘snapshot’ assessments of resource use. Our framework demonstrates how comparisons of invader and native functional responses, within and between Type II and III functional responses, allow testing of the likely population-level outcomes of invasions for affected species. Furthermore, we describe how recent studies support the predictive capacity of this method; for example, the invasive ‘bloody red shrimp’ Hemimysis anomala shows higher Type II functional responses than native mysids and this corroborates, and could have predicted, actual invader impacts in the field. The comparative functional response method can also be used to examine differences in the impact of two or more invaders, two or more populations of the same invader, and the abiotic (e.g. temperature) and biotic (e.g. parasitism) context-dependencies of invader impacts. Our framework may also address the previous lack of rigour in testing major hypotheses in invasion ecology, such as the ‘enemy release’ and ‘biotic resistance’ hypotheses, as our approach explicitly considers demographic consequences for impacted resources, such as native and invasive prey species. We also identify potential challenges in the application of comparative functional responses in invasion ecology. These include incorporation of numerical responses, multiple predator effects and trait-mediated indirect interactions, replacement versus non-replacement study designs and the inclusion of functional responses in risk assessment frameworks. In future, the generation of sufficient case studies for a meta-analysis could test the overall hypothesis that comparative functional responses can indeed predict invasive species impacts.