Constitutive Equations for Use in Design Analyses of Long-life Elevated Temperature Components

Design analysis needs and procedures relative to elevated temperature components in liquid metal fast breeder reactor (LMFBR) system were examined. The effects of the thermal transients on the pressure boundary components are enhanced by the excellent heat transfer properties of the liquid sodium coolant. Design criteria for high temperature nuclear reactor components recognize the potential occurrence of inelastic structural response. Specifically, criteria and limits were developed which reflect a recognition of this potential and employ design by analysis concepts that requires that inelastic (elastic-plastic and creep) analyses be performed. Constitutive equations to represent multiaxial time-dependent responses of LMFBR alloys are established. The development of equations applicable under cyclic loading conditions are outlined

Generalised Cantor sets and the dimension of products

In this paper we consider the relationship between the Assouad and box-counting dimension and how both behave under the operation of taking products. We introduce the notion of ‘equi-homogeneity’ of a set, which requires a uniformity in the cardinality of local covers at all length-scales and at all points, and we show that a large class of homogeneous Moran sets have this property. We prove that the Assouad and box-counting dimensions coincide for sets that have equal upper and lower box-counting dimensions provided that the set ‘attains’ these dimensions (analogous to ‘s-sets’ when considering the Hausdorff dimension), and the set is equi-homogeneous. Using this fact we show that for any α ∈ (0, 1) and any β, γ ∈ (0, 1) such that β + γ ≥ 1 we can construct two generalised Cantor sets C and D such that dimBC = αβ, dimBD = α γ, and dimAC = dimAD = dimA (C × D) = dimB (C × D) = α

Materials Characterization using the Backscattered Electron Signal in Scanning Electron Microscopy

The backscattered electron signal in scanning electron microscopy is sensitive to changes in the atomic number of the specimen. This atomic number information can be measured by calibrating the output of a backscattered electron detector from two known materials. The atomic number of an unknown sample can then be determined by measuring the backscattered electron signal from the unknown sample. Knowing the atomic number factor of an unknown sample and the heavy elements (Z \u3e 10 as determined from X-ray analysis), the existence of light elements can be detected. From a knowledge of the sample and valence information, the composition of a sample can often be characterised in terms of its chemical formula

Improving the Nutritional Quality of Food Markets through the Informal Sector: Lessons from Case Studies in Other Sectors

Policymakers in a number of countries in sub-Saharan Africa (SSA) are seeking to work with food markets and food businesses as part of efforts to reduce undernutrition. These market-based approaches include national fortification programmes, public food distribution systems, new product development and the promotion of biofortified crops. Food markets have clear potential to improve diets, including those of many low-income populations. However, current market-based approaches generally fail to engage a large and critical portion of these markets: informal businesses – particularly food traders, processors and retailers. It is the informal sector that supplies much of the food purchased by the poor, delivering products to the locations where they live, typically at very low prices. However, food in informal markets is often not sufficiently nutrient-rich and can be unsafe. Many policymakers regard the informal sector as a barrier to development or believe that it will quickly disappear with the spread of supermarkets and centralised food value chains. However, available evidence suggests that most food in SSA countries will continue to be sold in informal markets for the next several decades, due to broader economic and institutional conditions that favour informality. Policy approaches aiming to suppress the informal sector are generally ineffective; in some cases, they can actually decrease the quality and safety of food. Similarly, food and nutrition policies that simply ignore the informal sector may fail to have effects for low-income populations. Finally, nutrition initiatives that include the informal sector may contribute to the success of parallel initiatives involving formal businesses, since formal businesses generally compete with informal businesses and respond to their behaviours. Developing new approaches that engage informal food businesses is therefore an important policy priority. Yet programmatic action in the informal sector has not been examined in a systematic way in the context of food and nutrition. This Evidence Report helps to address this gap by analysing several programmes in other sectors that have sought to improve performance in informal markets in SSA. The report groups these programmes into three case studies: food safety interventions, programmes targeting small medicine sellers, and efforts to promote salt iodisation. The review finds that there are substantial benefits of adopting a facilitative approach towards informal businesses: in particular ‘light-touch’ interventions centred around training and behaviour change can yield significant improvements in the quality of products and services. At the same time, these approaches are not panaceas; the case studies emphasise that ‘light-touch’ interventions do not lead to technically perfect outcomes: post-intervention performance is patchy, and inappropriate products and practices remain. Yet, by triggering moderate improvements in informal markets, these programmes may have substantial benefits for the poor.UK Department for International Developmen

Electron Detectors Used for Imaging in the Scanning Electron Microscope

Electron detectors used for imaging in the scanning electron microscope include those which detect secondary electrons, various portions of the backscattered electron signal, and the residual specimen current. The use of a different detector will often produce a different image of the same specimen. The information contained in these images depends upon the signal detected and the properties of the detector used. The choice of detector to be used depends upon the information desired

Theoretical backgrounds of durability analysis by normalized equivalent stress functionals

Generalized durability diagrams and their properties are considered for a material under a multiaxial loading given by an arbitrary function of time. Material strength and durability under such loading are described in terms of durability, safety factor and normalized equivalent stress. Relations between these functionals are analysed. We discuss some material properties including time and load stability, self-degradation (ageing), and monotonic damaging. Phenomenological strength conditions are presented in terms of the normalized equivalent stress. It is shown that the damage based durability analysis is reduced to a particular case of such strength conditions. Examples of the reduction are presented for some known durability models. The approach is applicable to the strength and durability description at creep and impact loading and their combination

What children know about the source of their knowledge without reporting it as the source

We argue that, amongst 3- to 5- year-olds, failure to report the source of knowledge recently acquired in answer to “How do you know…?” is due to a specific failure to make a causal inference, in line with source monitoring theory but not fuzzy trace theory. In three Experiments, children (N = 37; 30; 59) identified a hidden toy by seeing, feeling, or by being told, having had two modes of access on each trial, one informative (e.g. seeing a toy identified by colour) and the other uninformative (e.g. being told the toy’s colour by the Experimenter who had only felt it). Children who answered the know question wrongly nevertheless reported accurately who saw and who felt the toy, and what the well-informed player had said. They also realised when the Experimenter’s uninformative access implied their own knowledge was unreliable, suggesting precocious working understanding of knowledge sources