Image quality, space-qualified UV interference filters

The progress during the contract period is described. The project involved fabrication of image quality, space-qualified bandpass filters in the 200-350 nm spectral region. Ion-assisted deposition (IAD) was applied to produce stable, reasonably durable filter coatings on space compatible UV substrates. Thin film materials and UV transmitting substrates were tested for resistance to simulated space effects

The tasks and roles of social workers: a focused overview of research evidence

Options for Excellence is a joint DfES and DH-funded review of the social care workforce. Four task groups have been set up, each dealing with different aspects of social care. Task Group 3 is considering the roles and tasks of social workers. In order to inform the work of this group, the Thomas Coram Research Unit was asked to provide an overview of relevant research and data in three main areas: the effective deployment of social worker time and tasks, improving cross-professional working, and attitudes to take-up of post-qualifying qualifications

The effects of organic farming on the soil physical environment

The aim of this research was to investigate the effects of organic farming practices on the development of soil physical properties, and in particular, soil structure in comparison with conventional agricultural management. The soil structure of organically and conventionally managed soils at one site was compared in a quantitative manner at different scales of observations using image analysis. Key soil physical and chemical properties were measured as well as the pore fractal geometry to characterise pore roughness. Organically managed soils had higher organic matter content and provided a more stable soil structure than conventionally managed soils. The higher porosity (%) at the macroscale in soil under conventional management was due to fewer larger pores while mesoand microscale porosity was found to be greater under organic management. Organically managed soils typically provided spatially well distributed pores of all sizes and of greater roughness compared to those under conventional management. These variations in the soil physical environment are likely to impact significantly on the performance of these soils for a number of key processes such as crop establishment and water availabilit

A Study of Heat Transfer and Heat Flow Asymmetry through Water in the presence of the Density Maximum

This thesis is concerned with heat flow asymmetry through composites of water and aqueous solutions. Central to this exploration are the behaviour of heat transfer in the vicinity of the density maximum and the behaviour of the temperature of maximum density of aqueous solutions. Both of these topics are investigated by cooling a rectangular enclosure of the test fluid in a quasi-steady state manner. During cooling, the temperature at select points within the liquid is monitored and the flow of heat at both isothermal walls is measured. As the liquid cools through its density maximum the normal single-cell convection that occurs in the presence of a horizontal temperature gradient changes to a double cell configuration in the vicinity of the density maximum. This transition manifests itself in changes in the horizontal temperature profile across the cavity and in the rate of cooling of the fluid. A measurement technique to study the behaviour of the temperature of maximum density of aqueous solutions is described in this thesis that relies on these changes. These changes are investigated experimentally and numerically. The study of the behaviour of heat transfer and the temperature of maximum density of aqueous solutions revealed that heat transfer is reduced in the vicinity of the density maximum and that the temperature of maximum density of aqueous solutions depends on the nature and concentration of the solute. Both of these results are exploited in the study of heat flow asymmetry through a device that consists of two cubic enclosures side by side; one enclosure contains water with a density maximum at 4oC and the other enclosure contains a saline solution with a density maximum at 2oC. A temperature gradient, which spans both of these temperatures of maximum density, is applied horizontally across the composite system, resulting in different rates of heat transfer through the device depending on the gradient direction. Experiments performed with a 12cm x 6cm x 6cm container yield heat transfer rates of 0.55W and 0.19W depending on the direction of the temperature gradient, resulting in a rectification factor of 65.4%. Asymmetrical heat transfer rates are also found in composite systems of water and solids when the temperature gradient spans the temperature of maximum density of the water. Results from computational fluid dynamics confirm the experimental results, and are used to investigate the influence of such parameters as temperature gradient and container aspect ratio on the rectification factor

Links Between Social Support, Thwarted Belongingness, and Suicide Ideation among Lesbian, Gay, and Bisexual College Students

Emerging adults with a lesbian, gay, or bisexual (LGB) identity are at greater risk for engaging in suicide-related behaviors. This disparity highlights a need to elucidate specific risk and protective factors associated with suicide-related behaviors among LGB youth, which could be utilized as targets for suicide prevention efforts in this population. Informed by the interpersonal-psychological theory of suicide, the present study hypothesized that social support would be indirectly associated with decreased suicide ideation via lower thwarted belongingness. A sample of 50 emerging adults (62.0% male, 70.0% Hispanic) who identified as gay, lesbian, bisexual, questioning, or “other” orientation, with a mean age of 20.84 years (SD = 3.30 years), completed self-report assessments. Results indicated that support from both family and the LGB community were associated with lower thwarted belongingness over and above the effects of age, sex, and depressive symptoms. Indirect effects models also indicated that both family and LGB community support were associated with suicide ideation via thwarted belongingness. The results of the present study suggest that family and LGB community support may represent specific targets for reducing thwarted belongingness that could be leveraged in suicide prevention efforts for LGB emerging adults

Highly electronegative metallic contacts to semiconductors using polymeric sulfur nitride

The Schottky barriers formed on n‐ZnS and n‐ZnSe by polymeric sulfur nitride have been compared to barriers formed by Au. Barrier energies as determined by photoresponse, current‐voltage, and capacitance‐voltage methods show that (SN)_x is approximately 1.0 eV higher than Au on n‐ZnS and 0.3–0.4 eV higher than Au on n‐ZnSe. We believe that this is the first report of any metallic contact more electronegative than Au

Model based methodology development for energy recovery in ash heat exchange systems

Flash tank evaporation combined with a condensing heat exchanger can be used when heat exchange is required between two streams and where at least one of these streams is difficult to handle (in terms of solid particles content, viscosity, pH, consistency etc.). To increase the efficiency of heat exchange, a cascade of these units in series can be used. Heat transfer relationships in such a cascade are very complex due to their interconnectivity, thus the impact of any changes proposed is difficult to predict. In this report, a mathematical model of a single unit ash tank evaporator combined with a condensing heat exchanger unit is proposed. This model is then developed for a chain of the units. The purpose of this model is to allow an accurate evaluation of the effect and result of an alteration to the system. The resulting model is applied to the RUSAL Aughinish Alumina digester area

Root anatomical traits contribute to deeper rooting of maize under compacted field conditions

© The Author(s) 2020. To better understand the role of root anatomy in regulating plant adaptation to soil mechanical impedance, 12 maize lines were evaluated in two soils with and without compaction treatments under field conditions. Penetrometer resistance was 1–2 MPa greater in the surface 30 cm of the compacted plots at a water content of 17–20% (v/v). Root thickening in response to compaction varied among genotypes and was negatively associated with rooting depth at one field site under non-compacted plots. Thickening was not associated with rooting depth on compacted plots. Genotypic variation in root anatomy was related to rooting depth. Deeper-rooting plants were associated with reduced cortical cell file number in combination with greater mid cortical cell area for node 3 roots. For node 4, roots with increased aerenchyma were deeper roots. A greater influence of anatomy on rooting depth was observed for the thinner root classes. We found no evidence that root thickening is related to deeper rooting in compacted soil; however, anatomical traits are important, especially for thinner root classes