On the interaction of small and large eddies in two dimensional turbulent flows

Some results concerning the interaction of small and large eddies to two dimensional turbulent flows are presented. It is shown that the amplitude of small structures decays exponentially to a small value, and from this is inferred a simplified interaction law of small and large eddies. Beside their intrinsic interest for the understanding of the physics of turbulence, these results lead to new numerical schemes to be studied in a separate work

Included @ Work: A Global Campaign

[Excerpt] This campaign is just a beginning and we hope that you will be able to play your part in working with us and others who feel like us that want to see people with disabilities experiencing no disadvantage in obtaining work and employment and developing careers of their choice

A Critical Review of the Measurement of Ice Adhesion to Solid Substrates

Ice adhesion is an issue spanning a wide range of technical fields. In the aerospace industry, ice accretion has led to a large number of casualties and costs the industry billions of dollars every year. To design effective anti-/de-icing systems, the adhesion of ice to surfaces must be understood. In this review paper, the authors surveyed for papers providing methods for the measurement of ice adhesion. 113 papers were identified for comparison, with data being extracted from 58 papers with common test surfaces (aluminum, steel, Teflon (Chemours), and polyurethane). The methods used were categorized and data were compared based on their precision and the trends they demonstrated. Conceptual problems were identified with the tests used in the literature and discussed, and open questions relevant to testing the adhesion of ice were identified. Several key parameters affecting ice adhesion identified from the literature were temperature, surface roughness, strain rate, and impact velocity. Their effects on adhesion strength were discussed. While researching this topic, it was discovered that many papers did not report the strain rate in their tests, and the vast majority of papers did not correct their data for stress concentrations on the surface, either of which has been shown to cause variation in the data by one order of magnitude. Data compared from the literature typically spanned one to three orders of magnitude. The causes of these variations were discussed

Social work training or social work education? An approach to curriculum design

Population ageing, economic circumstances, and human behaviour are placing social welfare systems under great strain. In England extensive reform of the social work profession is taking place. Training curricula are being redesigned in the context of new standards of competence for social workers – the Professional Capabilities Framework (PCF). Students must be equipped on qualifying to address an extensive range of human problems, presenting major challenges to educators. Critical theory suggests an approach to tackle one such challenge – selecting the essential content required for areas of particular practice. Teaching on social work with older people is used to illustrate this. Habermas’ theory of cognitive interests highlights the different professional roles served by the social work knowledge base - instrumental, interpretive, and emancipatory. Howe’s application of sociological theory distinguished four social work roles corresponding to these. It is suggested that curriculum design decisions must enable practitioners to operate in each. When preparing students to work with older people, educators therefore need to include interpretive and emancipatory perspectives, and not construct social work purely as an instrumental response to problems older people present. This approach provides one useful rationale for curriculum design decisions, which is applicable to other areas of practice, and to contexts outside England

Oxidative stress and the use of antioxidants in stroke

Transient or permanent interruption of cerebral blood flow by occlusion of a cerebral artery gives rise to an ischaemic stroke leading to irreversible damage or dysfunction to the cells within the affected tissue along with permanent or reversible neurological deficit. Extensive research has identified excitotoxicity, oxidative stress, inflammation and cell death as key contributory pathways underlying lesion progression. The cornerstone of treatment for acute ischaemic stroke remains reperfusion therapy with recombinant tissue plasminogen activator (rt-PA). The downstream sequelae of events resulting from spontaneous or pharmacological reperfusion lead to an imbalance in the production of harmful reactive oxygen species (ROS) over endogenous anti-oxidant protection strategies. As such, anti-oxidant therapy has long been investigated as a means to reduce the extent of injury resulting from ischaemic stroke with varying degrees of success. Here we discuss the production and source of these ROS and the various strategies employed to modulate levels. These strategies broadly attempt to inhibit ROS production or increase scavenging or degradation of ROS. While early clinical studies have failed to translate success from bench to bedside, the combination of anti-oxidants with existing thrombolytics or novel neuroprotectants may represent an avenue worthy of clinical investigation. Clearly, there is a pressing need to identify new therapeutic alternatives for the vast majority of patients who are not eligible to receive rt-PA for this debilitating and devastating disease