25,631 research outputs found

    Carbonate Formation in Non-Aqueous Environments by Solid-Gas Carbonation of Silicates

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    We have produced synthetic analogues of cosmic silicates using the Sol Gel method, producing amorphous silicates of composition Mg(x)Ca(1-x)SiO3. Using synchrotron X-ray powder diffraction on Beamline I11 at the Diamond Light Source, together with a newly-commissioned gas cell, real-time powder diffraction scans have been taken of a range of silicates exposed to CO2 under non-ambient conditions. The SXPD is complemented by other techniques including Raman and Infrared Spectroscopy and SEM imaging.Comment: 5 pages, 3 figures. Contribution to the Proceedings of the First European Conference on Laboratory Astrophysics (ECLA

    Towards the Distributed Burning Regime in Turbulent Premixed Flames

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    Three-dimensional numerical simulations of canonical statistically-steady statistically-planar turbulent flames have been used in an attempt to produce distributed burning in lean methane and hydrogen flames. Dilatation across the flame means that extremely large Karlovitz numbers are required; even at the extreme levels of turbulence studied (up to a Karlovitz number of 8767) distributed burning was only achieved in the hydrogen case. In this case, turbulence was found to broaden the reaction zone visually by around an order of magnitude, and thermodiffusive effects (typically present for lean hydrogen flames) were not observed. In the preheat zone, the species compositions differ considerably from those of one-dimensional flames based a number of different transport models (mixture-averaged, unity Lewis number, and a turbulent eddy viscosity model). The behaviour is a characteristic of turbulence dominating non-unity Lewis number species transport, and the distinct limit is again attributed to dilatation and its effect on the turbulence. Peak local reaction rates are found to be lower in the distributed case than in the lower Karlovitz cases but higher than in the laminar flame, which is attributed to effects that arise from the modified fuel-temperature distribution that results from turbulent mixing dominating low Lewis number thermodiffusive effects. Finally, approaches to achieve distributed burning at realisable conditions are discussed; factors that increase the likelihood of realising distributed burning are higher pressure, lower equivalence ratio, higher Lewis number, and lower reactant temperature

    The impact of narcissistic personality disorder on others: A study of romantic partners and family members

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    Narcissistic personality disorder (NPD) is a diagnosed mental health disorder that affects up to 6.2% of the population. NPD is known to have a strong interpersonal component, as individuals express their vulnerabilities to others in ways that are challenging. For instance, a person may sometimes seem grandiose and prone to intense hostility, but at other times seem vulnerable and needy, yet difficult to please. However, while the presence of interpersonal dysfunction has been identified for individuals with NPD, little is known about how this is experienced by partners and family members. This thesis presents four original studies on the impact of NPD on romantic partners and family members to progress our understanding of the disorder and improve treatment. Method: The thesis begins with a critical review of existing literature regarding the construct of NPD to determine new research questions to be addressed (Chapter 1). Chapter 2 presents a study of partners and family in a close relationship with someone with NPD (N = 683) to assess levels of grief, burden, coping and mental health. Thematic analysis of a subset of participants\u27 qualitative descriptions of their relative was conducted (N = 436), exploring the characteristics of the NPD relative (chapter 3) and their interpersonal interactions (chapter 4). Finally, some participants (N = 15) were asked to provide detailed narratives comparing their relationships with their relative and with others (chapter 5), to study core conflictual relationship themes (CCRTs). Chapter 6 provides an overview of research findings and outlines implications for the assessment, diagnosis and treatment of individuals with NPD, but also targeted therapeutic supports for partners and family members. Results: Participants living with a relative with NPD were suffering significant psychological symptoms (69% depression, 82% anxiety) and high burden (chapter 2). Levels of symptoms and burden were higher than individuals living with people diagnosed with borderline personality disorder or other severe mental illness. Participant’s descriptions of their relative (chapter 3) included both “grandiose” tendencies (including entitlement, envy and exploitativeness) but also “vulnerable” ones (including hypersensitivity, insecurity and emptiness). The relationship included themes of coercive control (chapter 4), where the relative made challenging physical, verbal, emotional, financial and sexual demands. Fluctuations in idealisation, devaluation, hostility, and dependency were often present in the relationship. Relationship narratives involving relatives with pathological narcissism involved more instances of disharmony, including relatives rejecting, subjugating and attacking behaviours, and participants rejecting and withdrawing behaviours, corresponding with a deactivation of participants attachment system (chapter 5). Conclusion: Living with a person with NPD appears to inflict a considerable psychological toll on those closest to the person. While narcissistic grandiosity, coercive control and interpersonal antagonism may serve to protect the individual who is suffering, these have an insidious effect on partners and family members. Treatments for NPD are limited, with no randomised controlled trials. The findings presented here have two major implications for therapy. First, that the disorder has severe impacts on others, meaning the mental health needs of close relatives should be assessed. Second, that therapists will need specific, targeted support to help them work with individuals with NPD, to help navigate fluctuations of grandiosity and vulnerability in this patient group, sometimes prone to being coercive, controlling and hostile, whilst also presenting as needy and insecure

    Supply chain challenges for sustainability: the case of waste textiles as raw materials

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    Purpose: This paper addresses the growing problem of textile waste in the rapidly developing cities of subSaharan Africa and examines, from a supply chain perspective, the potential for waste textile materials to be transformed into the raw materials for new consumer products. Research Approach: The paper reflects on the outcomes of a field trip to Dar es Salaam in which stakeholders in a hypothesised textile waste supply chain were interviewed and waste textile materials were analysed in order to determine their content and appropriateness for reuse. Findings from the field study have been compared with current literature on logistics and market creation, waste generation, management and recycling in sub-Saharan Africa. Findings and Originality: The findings show that a rudimentary system has been in place for many years to collect and recycle textiles in Dar es Salaam. However, at the same time as textile waste is projected to increase in the city, collection rates are falling. The chief reasons for the falling rates are failures in the ‘modernised mixture’ approach to waste collection employed by Dar es Salaam City Council and market failure for the collected materials. Alternative combinations of ‘modernised mixtures’, incorporating community-based organisations, are likely to increase textile yields from unplanned urban areas but previous high-profile failures in such systems within Dar es Salaam mean there is caution on both sides in entering into such a relationship. The more pressing problem is to identify appropriate end markets for the textile materials, since in a country where recycling is entirely market-driven, failure to do so will undermine any attempt to improve the collection system. Whilst many studies have considered general recycling practices in sub-Saharan Africa, there are few investigations into textile waste. Furthermore, those existing studies do not consider the importance of understanding fibre composition of the materials in order to determine the most appropriate end markets. Research Impact: The research contributes to the growing body of knowledge on ‘bottom of the pyramid’ approaches to sustainable futures. Practical Impact: The work presented considers supply chain problems and offers approaches to tackling the increasing waste management issues of Dar es Salaam and proposes a mechanism for doing so which has the potential to provide income for the poorest sectors of the urban society

    High Density Mesoscopic Atom Clouds in a Holographic Atom Trap

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    We demonstrate the production of micron-sized high density atom clouds of interest for meso- scopic quantum information processing. We evaporate atoms from 60 microK, 3x10^14 atoms/cm^3 samples contained in a highly anisotropic optical lattice formed by interfering di racted beams from a holographic phase plate. After evaporating to 1 microK by lowering the con ning potential, in less than a second the atom density reduces to 8x10^13 cm^- 3 at a phase space density approaching unity. Adiabatic recompression of the atoms then increases the density to levels in excess of 1x10^15 cm^-3. The resulting clouds are typically 8 microns in the longest dimension. Such samples are small enough to enable mesoscopic quantum manipulation using Rydberg blockade and have the high densities required to investigate new collision phenomena.Comment: 4 pages, 4 figures, submitted to PR
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