Parametric study of beam refraction problems across laser anemometer windows

The experimenter is often required to view flows through a window with a different index of refraction than either the medium being observed or the medium that the laser anemometer is immersed in. The refraction that occurs at the window surfaces may lead to undesirable changes in probe volume position or beam crossing angle and can lead to partial or complete beam uncrossing. This report describes the results of a parametric study of this problem using a ray tracing technique to predict these changes. The windows studied were a flat plate and a simple cyclinder. For the flat-plate study: (1) surface thickness, (2) beam crossing angle, (3) bisecting line - surface normal angle, and (4) incoming beam plane surface orientation were varied. For the cylindrical window additional parameters were also varied: (1) probe volume immersion, (2) probe volume off-radial position, and (3) probe volume position out of the R-theta plane of the lens. A number of empirical correlations were deduced to aid the interested reader in determining the movement, uncrossing, and change in crossing angle for a particular situation

Is Targeting Formal Childcare the Best Way to Meet the Needs of Families in Britain?

The overall aim of this paper is to examine the types and combinations of childcare being used by parents in Britain, and to compare how this childcare usage may vary between families, in order to critically examine parental childcare needs. The three specific research questions were: 1) ‘What types and combinations of childcare are being used by families?’, 2) ‘What are the socio-demographic comparisons between families using and not using childcare?’ And 3) ‘How do types of childcare vary between families?. These questions were addressed by carrying out a secondary analysis of large-scale nationally representative datasets which provide information about patterns of childcare usage in the UK. Two main datasets were used: the Family Resources Survey and the Childcare and Early Years Survey of Parents, with analysis carried out for the years 2008 to 2013. The analysis carried out comes from a wider study seeking to examine the provision and use of preschool childcare in Britain. The findings show that despite policies to increase the use of formal childcare, parents continue to be reliant on informal care, especially grandparents, to supplement their childcare needs. Furthermore, childcare use is not equally distributed, but is related to family circumstances. For example formal care is used more by employed, higher income families, whilst informal care is used more by mothers who are not employed, less well educated and by younger mothers. The results overall suggest that formal and informal childcare in combination will better support maternal employment. Future government policy needs to address supporting this mixed provision. The data however says nothing about parental childcare preferences which are needed to unpack the observed patterns of childcare usage in the UK

Low voltage control of ferromagnetism in a semiconductor p-n junction

The concept of low-voltage depletion and accumulation of electron charge in semiconductors, utilized in field-effect transistors (FETs), is one of the cornerstones of current information processing technologies. Spintronics which is based on manipulating the collective state of electron spins in a ferromagnet provides complementary technologies for reading magnetic bits or for the solid-state memories. The integration of these two distinct areas of microelectronics in one physical element, with a potentially major impact on the power consumption and scalability of future devices, requires to find efficient means for controlling magnetization electrically. Current induced magnetization switching phenomena represent a promising step towards this goal, however, they relay on relatively large current densities. The direct approach of controlling the magnetization by low-voltage charge depletion effects is seemingly unfeasible as the two worlds of semiconductors and metal ferromagnets are separated by many orders of magnitude in their typical carrier concentrations. Here we demonstrate that this concept is viable by reporting persistent magnetization switchings induced by short electrical pulses of a few volts in an all-semiconductor, ferromagnetic p-n junction.Comment: 11 pages, 4 figure

Domestic retrofit: understanding capabilities of micro enterprise building practitioners

To deliver effective domestic retrofit at scale, it is essential to understand the current and required capabilities of building practitioners working in the repair, maintenance and improvement (RMI) of existing buildings. Capability research in the construction sector has previously focused on large projects, but small, and particularly, micro-firms that undertake RMI and form 77% of workers in construction, are under-researched. This gap is addressed by the present study on the capabilities of the practitioners and the contextual opportunities to deploy capabilities. The study analysed data from interviews (n = 27) with micro-enterprise building practitioners working in the UK’s RMI sector. Template analysis was conducted by applying an established model of behaviour change: Capability, Opportunity, Motivation—Behaviour (COM-B). Under Capability, three main themes were identified: knowledge, business management and individual characteristics. Under Opportunities, the main themes were state action, market and customer demand, technology diffusion, networks and business management. Under Motivation the themes were pride in work, good working relationships, maintaining a viable business and customer satisfaction. Practitioners are continually learning and problem-solving, developing trust and creating positive professional relationships. Working with these existing capabilities, experiential learning on-site and peer-to-peer training are recommended to scale up capability. For capabilities to be deployed, policy must enable opportunities across the multiple contexts micro-enterprise practitioners operate within, including training and incentives across the supply chain network and in stimulating demand