1,477 research outputs found

    The evaluation of a novel haptic machining VR-based process planning system using an original process planning usability method

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    This thesis provides an original piece of work and contribution to knowledge by creating a new process planning system; Haptic Aided Process Planning (HAPP). This system is based on the combination of haptics and virtual reality (VR). HAPP creates a simulative machining environment where Process plans are automatically generated from the real time logging of a user’s interaction. Further, through the application of a novel usability test methodology, a deeper study of how this approach compares to conventional process planning was undertaken. An abductive research approach was selected and an iterative and incremental development methodology chosen. Three development cycles were undertaken with evaluation studies carried out at the end of each. Each study, the pre-pilot, pilot and industrial, identified progressive refinements to both the usability of HAPP and the usability evaluation method itself. HAPP provided process planners with an environment similar to which they are already familiar. Visual images were used to represent tools and material whilst a haptic interface enabled their movement and positioning by an operator in a manner comparable to their native setting. In this way an intuitive interface was developed that allowed users to plan the machining of parts consisting of features that can be machined on a pillar drill, 21/2D axis milling machine or centre lathe. The planning activities included single or multiple set ups, fixturing and sequencing of cutting operations. The logged information was parsed and output to a process plan including route sheets, operation sheets, tool lists and costing information, in a human readable format. The system evaluation revealed that HAPP, from an expert planners perspective is perceived to be 70% more satisfying to use, 66% more efficient in completing process plans, primarily due to the reduced cognitive load, is more effective producing a higher quality output of information and is 20% more learnable than a traditional process planning approach

    “Double Punishment” - The Proceeds of Crime Act 2002 (POCA): A Qualitative Examination of the Post-Conviction Confiscation Punishment in England and Wales.

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    Over the past few decades there has been an increasing use of asset recovery powers which claim to confiscate ‘ill-gotten’ gains from offenders who derive profit from their crimes. The embodiment of this came in the form of the Proceeds of Crime Act 2002, a piece of legislation that consolidated previous asset recovery legislation and which set out to make sure that ‘crime does not pay’ (Rees et al., 2012). Whilst the Proceeds of Crime Act 2002 provides a number of asset recovery routes, the most frequently used within England and Wales is post-conviction confiscation (ibid). Despite the increasing use of confiscation powers there is an absence of research which accounts for the voices of those who are subject to this punishment. Such insights may be key to developing an understanding of the ‘true’ impact of the post-conviction confiscation punishment upon the defendant and their families and illuminate whether this system of punishment meets its wider crime control objectives. Therefore, through the analysis of narrative ‘interviews’ with twenty-one individuals who have been subject to the post-conviction confiscation punishment, this qualitative study investigates the lived reality of being subject to this contemporary form of punishment. Based upon its findings, this thesis will argue that this form of punishment represents a further level of punishment despite no further offence being committed; that it is a punishment that once inflicted becomes a ‘life sentence’ that is said to be inescapable; that it disproportionately impacts upon the [innocent] families of the confiscation defendant; that it fails to meet its stated objectives and has no social defence (Mathieson, 2009); and, in revealing both its iatrogenic and criminogenic nature, this thesis argues not for the reform of post-conviction confiscation, but for its abolition

    Solar Particle Acceleration at Reconnecting 3D Null Points

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    Context: The strong electric fields associated with magnetic reconnection in solar flares are a plausible mechanism to accelerate populations of high energy, non-thermal particles. One such reconnection scenario occurs at a 3D magnetic null point, where global plasma flows give rise to strong currents in the spine axis or fan plane. Aims: To understand the mechanism of charged particle energy gain in both the external drift region and the diffusion region associated with 3D magnetic reconnection. In doing so we evaluate the efficiency of resistive spine and fan models for particle acceleration, and find possible observables for each. Method: We use a full orbit test particle approach to study proton trajectories within electromagnetic fields that are exact solutions to the steady and incompressible magnetohydrodynamic equations. We study single particle trajectories and find energy spectra from many particle simulations. The scaling properties of the accelerated particles with respect to field and plasma parameters is investigated. Results: For fan reconnection, strong non-uniform electric drift streamlines can accelerate the bulk of the test particles. The highest energy gain is for particles that enter the current sheet, where an increasing "guide field" stabilises particles against ejection. The energy is only limited by the total electric potential energy difference across the fan current sheet. The spine model has both slow external electric drift speed and weak energy gain for particles reaching the current sheet. Conclusions: The electromagnetic fields of fan reconnection can accelerate protons to the high energies observed in solar flares, gaining up to 0.1 GeV for anomalous values of resistivity. However, the spine model, which gave a harder energy spectrum in the ideal case, is not an efficient accelerator after pressure constraints in the resistive model are included.Comment: 15 pages, 14 figures. Submitted to Astronomy and Astrophysic

    Effects of Enrichment and Litter Parity on Reproductive Performance and Behavior in BALB/c and 129/Sv Mice

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    We examined the effect of adding species-appropriate environmental enrichment items to breeding cages of BALB/cAnNCrl and 129S2/SvPasCrl mice. The 3 enrichment conditions were: 1) cotton nesting material; 2) nesting material plus a paper shelter and rolled paper bedding; and 3) an igloo dome with an exercise wheel in addition to the shelter-group enrichments. We measured litter size, litter survival to weaning age, average pup weight at 21 d, and the interlitter interval to evaluate reproductive performance. A random subset of the first- or second-litter offspring from each enrichment condition and strain was assessed in multiple behavioral tests. Enrichment significantly affected anxiety-like behavior and sociability, with the direction of change dependent on strain and sex. Litter parity had greater effects on some reproductive parameters than did the enrichment condition, and this effect was not solely due to a difference between the first compared with subsequent litters. The significant effects of litter parity on the number of pups born and weaned, female pup weight, and interlitter interval were dependent on the enrichment condition in BALB/c but not 129/Sv mice. Offspring from the first or second litter were included in a generational component to investigate whether enrichment effects on reproduction persist in adult offspring after transfer to a different facility for breeding. Natal cage enrichment had no effect on any reproductive parameter in the transferred mice. Overall, additional enrichment beyond nesting material had a beneficial effect on the interlitter interval in BALB/c mice and on the number of pups weaned in 129/Sv mice

    Dietary Supplementation with Ethyl Ester Concentrates of Fish Oil (n-3) and Borage Oil (n-6) Polyunsaturated Fatty Acids Induces Epidermal Generation of Local Putative Anti-Inflammatory Metabolites

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    Clinical reports have attributed the amelioration of chronic inflammatory skin disorders to the presence of certain polyunsaturated fatty acids (PUFA) in dietary oils. To test the hypothesis of a local modulatory effect of these PUFA in the epidermis, the basal diet of normal guinea pigs was supplemented with ethyl esters of either fish oil [rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] or borage oi1 [rich in gamma-linolenic acid (GLA)]. Our data demonstrated that dietary oils influence the distribution of PUFA in epidermal phospholipids and the epidermal levels of PUFA-derived hydroxy fatty acids. Specifically, animals supplemented with ethyl esters of fish oil markedly incorporated EPA and DHA into epidermal phospholipids, which paralleled the epidermal accumulation of 1 5-hydroxyeicosapentaenoic acid (15-HEPE) and 17-hydroxydocosahexaenoic acid (17-HDoHE). Similarly, animals supplemented with esters of borage oil preferentially incorporated dihomogammalinolenic acid (DGLA), the epidermal elongase product of GLA, into the epidermal phospholipids, which also was ac- companied by epidermal accumulation of 15-hydroxyeicosatrienoic acid (15-HETrE). By factoring the epidermal levels of the 15-lipoxygenase products and their relative inhibitory potencies, we evolved a measure of the overall potential of dietary oils to exert local anti-inflammatory effect. For example, the leukotriene inhibition potentials (LIP) of both fish oil and borage oil were greatly enhanced when compared to controls. Thus, the altered profiles of epidermal 15-lipoxygenase products generated from particular dietary oils may be responsible, at least in part, for reported ameliorative effects of oils on chronic inflammatory skin disorders

    Northern Harrier, Circus cyaneus, Attacks on Greater Sage-Grouse, Centerocercus urophasianus, in Southern Alberta

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    The Greater Sage-Grouse (Centrocercus urophasianus) is an endangered species in Canada, making it critical to understand all known causes of mortality. We report the first recorded observations of female Northern Harrier (Circus cyaneus) attacks on male Greater Sage-Grouse. Although no attacks were successful, our observations suggest that Northern Harriers are predators of Greater Sage-Grouse

    A family of nitrogen enriched metal organic frameworks with CCS potential

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    Materials with enhanced carbon capture capacities are required to advance post-combustive amelioration methods; these are necessary to reduce atmospheric carbon dioxide emissions and the associated rate of global temperature increase. Current technologies tend to be very energy intensive processes with high levels of waste produced; this work presents three new metal organic framework materials with embedded Lewis base functionalities, imparted by the nitrogen-rich ligand, demonstrating an affinity for carbon dioxide. Thus , we report the synthesis and characterization of a series of metal organic framework materials using a range of metal centers (Co, Ni, and Zn) with the 1,4-bis(pyridin-4-yl)-1,2,4,5-tetrazine organic linker, in the presence of ammonium hexafluorosilicate. Three distinct crystal structures are reported for Zn-pytz(hydro) 1D chains, and Ni-pytz and Co-pytz isostructural 1D Ladders. Co-pytz shows an uptake of 47.53mg CO2/g of sorbent, which equates to 15 wt % based on available nitrogen sites within the structure, demonstrating potential for carbon capture applications
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