1,813 research outputs found

    Suspended liquid particle disturbance on laser-induced blast wave and low density distribution

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    The impurity effect of suspended liquid particles on the laser-induced gas breakdown was experimentally investigated in quiescent gas. The focus of this study is the investigation of the influence of the impurities on the shock wave structure as well as the low density distribution. A 532 nm Nd:YAG laser beam with an 188 mJ/pulse was focused on the chamber filled with suspended liquid particles 0.9 ± 0.63 Όm in diameter. Several shock waves are generated by multiple gas breakdowns along the beam path in the breakdown with particles. Four types of shock wave structures can be observed: (1) the dual blast waves with a similar shock radius, (2) the dual blast waves with a large shock radius at the lower breakdown, (3) the dual blast waves with a large shock radius at the upper breakdown, and (4) the triple blast waves. The independent blast waves interact with each other and enhance the shock strength behind the shock front in the lateral direction. The triple blast waves lead to the strongest shock wave in all cases. The shock wave front that propagates toward the opposite laser focal spot impinges on one another, and thereafter a transmitted shock wave (TSW) appears. The TSW interacts with the low density core called a kernel; the kernel then longitudinally expands quickly due to a Richtmyer-Meshkov-like instability. The laser-particle interaction causes an increase in the kernel volume which is approximately five times as large as that in the gas breakdown without particles. In addition, the laser-particle interaction can improve the laser energy efficiency

    Grass Seed Production Guide for Utah

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    Transport and Photo-Conduction in Carbon Nanotube Fibers

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    We have characterized the conductivity of carbon nanotubes (CNT) fibers enriched in semiconducting species as a function of temperature and pulsed laser irradiation of 266 nm wavelength. While at high temperatures the response approaches an Arrhenius law behavior, from room temperature down to 4.2 K the response can be framed, quantitatively, within the predictions of the fluctuation induced tunneling which occurs between the inner fibrils (bundles) of the samples and/or the elementary CNTs constituting the fibers. Laser irradiation induces an enhancement of the conductivity, and analysis of the resulting data confirms the (exponential) dependence of the potential barrier upon temperature as expected from the fluctuation induced tunneling model. A thermal map of the experimental configuration consisting of laser-irradiated fibers is also obtained via COMSOL simulations in order to rule out bare heating phenomena as the background of our experiments. (*) AuthorComment: 13 pages and 7 figure

    Statistical Similarities Between WSA‐ENLIL+Cone Model and MAVEN in Situ Observations From November 2014 to March 2016

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    Normal solar wind flows and intense solar transient events interact directly with the upper Martian atmosphere due to the absence of an intrinsic global planetary magnetic field. Since the launch of the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, there are now new means to directly observe solar wind parameters at the planet’s orbital location for limited time spans. Due to MAVEN’s highly elliptical orbit, in situ measurements cannot be taken while MAVEN is inside Mars’ magnetosheath. To model solar wind conditions during these atmospheric and magnetospheric passages, this research project utilized the solar wind forecasting capabilities of the WSA‐ENLIL+Cone model. The model was used to simulate solar wind parameters that included magnetic field magnitude, plasma particle density, dynamic pressure, proton temperature, and velocity during a four Carrington rotation‐long segment. An additional simulation that lasted 18 Carrington rotations was then conducted. The precision of each simulation was examined for intervals when MAVEN was in the upstream solar wind, that is, with no exospheric or magnetospheric phenomena altering in situ measurements. It was determined that generalized, extensive simulations have comparable prediction capabilities as shorter, more comprehensive simulations. Generally, this study aimed to quantify the loss of detail in long‐term simulations and to determine if extended simulations can provide accurate, continuous upstream solar wind conditions when there is a lack of in situ measurements.Plain Language SummaryIf we ever have a manned mission to Mars, one of the numerous concerns would be space weather conditions and their effects on spacecraft in flight. One particular element of space weather that we like to focus on is solar wind: plasma that is continuously emitted from the Sun. Solar wind can effect communication between Earth and spacecraft, GPS services, and other vital elements of space travel. We therefore want a good understanding of space weather and want to forecast conditions before ever traveling there. Currently, there are not always means to directly measure solar wind, so we rely on numerical models. In this study, we used the model called WSA‐ENLIL+Cone to compare its solar wind measurements and one of our spacecraft orbiting Mars to see how well it did and to see if we can rely on it for solar wind forecasts. As it turns out, the model can be used for forecasting baseline values of different solar wind parameters, for example, temperature, even with limited information. We show in this study that the WSA‐ENLIL+Cone model allows us to forecast solar wind conditions and helps us to understand what is going on at that seemingly barren planet.Key PointsGeneralized, extensive WEC model simulations provide analogous confidence levels and results as detailed, relatively short simulationsWSA‐ENLIL+Cone model succeeds at predicting fast solar wind radial velocityPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142959/1/swe20547.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142959/2/swe20547_am.pd

    Schools and the legacy of hybrid buildings

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    Learning from the past, collecting data on the Italian condition of school buildings, our R&D work aimed to question the design process of school buildings in Italy introducing an innovative model of school, which turned the conventional and isolated, mono-functional and rigid school buildings into interior urban public spaces and porous community hubs to empower the communities around them and to become manifestos of sustainability. Through some built examples of school buildings designed in Italy, the paper discusses the outputs and impact of the introduction of new design layouts, participation projects with different stakeholders and sustainability. The research has guided the introduction of the new Italian guide-lines for school building design, approved in 2013. A future perspective to be explored is the reconsideration of exporting the strategy in different contexts and to design reconsider other public infrastructures turning the mono-functional use of public buildings into hybrid and multifunctional ones

    Power laws in microrheology experiments on living cells: comparative analysis and modelling

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    We compare and synthesize the results of two microrheological experiments on the cytoskeleton of single cells. In the first one, the creep function J(t) of a cell stretched between two glass plates is measured after applying a constant force step. In the second one, a micrometric bead specifically bound to transmembrane receptors is driven by an oscillating optical trap, and the viscoelastic coefficient Ge(ω)G_e(\omega) is retrieved. Both J(t)J(t) and Ge(ω)G_e(\omega) exhibit power law behavior: J(t)=A(t/t0)αJ(t)= A(t/t_0)^\alpha and Gˉe(ω)=ˉG0(ω/ω0)α\bar G_e(\omega)\bar = G_0 (\omega/\omega_0)^\alpha, with the same exponent α≈0.2\alpha\approx 0.2. This power law behavior is very robust ; α\alpha is distributed over a narrow range, and shows almost no dependance on the cell type, on the nature of the protein complex which transmits the mechanical stress, nor on the typical length scale of the experiment. On the contrary, the prefactors A0A_0 and G0G_0appear very sensitive to these parameters. Whereas the exponents α\alpha are normally distributed over the cell population, the prefactors A0A_0 and G0G_0 follow a log-normal repartition. These results are compared with other data published in the litterature. We propose a global interpretation, based on a semi-phenomenological model, which involves a broad distribution of relaxation times in the system. The model predicts the power law behavior and the statistical repartition of the mechanical parameters, as experimentally observed for the cells. Moreover, it leads to an estimate of the largest response time in the cytoskeletal network: τm≈1000\tau_m \approx 1000 s.Comment: 47 pages, 14 figures // v2: PDF file is now Acrobat Reader 4 (and up) compatible // v3: Minor typos corrected - The presentation of the model have been substantially rewritten (p. 17-18), in order to give more details - Enhanced description of protocols // v4: Minor corrections in the text : the immersion angles are estimated and not measured // v5: Minor typos corrected. Two references were clarifie

    D2 receptor occupancy of olanzapine pamoate depot using positron emission tomography : an open-label study in patients with schizophrenia

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    A long-acting depot formulation of olanzapine that sustains plasma olanzapine concentrations for over a month after a single injection is currently under development. This multicenter, open-label study explored D2 receptor occupancy of a fixed dose of olanzapine pamoate (OP) depot given every 4 weeks. Patients (nine male, five female) with schizophrenia or schizoaffective disorder previously stabilized on oral olanzapine were switched to OP depot 300 mg by intramuscular injection every 4 weeks for 6 months. No visitwise within-group significant changes were found in Brief Psychiatric Rating Scale Total or Clinical Global Impressions-Severity of Illness scores, although seven patients received oral olanzapine supplementation during the first four injection cycles. To minimize impact on D2 occupancy, positron emission tomography (PET) scans were not completed during injection cycles that required supplemental oral olanzapine. Two patients reported transient injection site adverse events, which did not result in discontinuation. The most frequently reported treatment-emergent adverse events were insomnia, aggravated psychosis, and anxiety. Mean striatal D2 receptor occupancy, as measured by [11C]-raclopride PET, was 69% on oral olanzapine (5–20 mg/day) and 50% (trough) on OP depot at steady state. Following an initial decline, occupancy returned to 84% of baseline oral olanzapine occupancy after six injections. Over the study period, D2 receptor occupancy and plasma olanzapine concentrations were significantly correlated (r=0.76, Pless than or equal to0.001). OP depot resulted in mean D2 receptor occupancy of approximately 60% or higher at the end of the 6-month study period, a level consistent with antipsychotic efficacy and found during treatment with oral olanzapine. However, supplemental oral olanzapine or another dosing strategy may be necessary to maintain adequate therapeutic response during the first few injection cycles.peer-reviewe

    The frontiers of participatory public engagement

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    Currently missing from critical literature on public engagement with academic research is a public-centric analysis of the wider contemporary context of developments in the field of public engagement and participation. Drawing on three differently useful strands of the existing theoretical literature on the public, this article compares a diverse sample of 100 participatory public engagement initiatives in order to first, analyse a selection of the myriad ways that the public is being constituted and supported across this contemporary field and second, identify what socio-cultural researchers might learn from these developments. Emerging from this research is a preliminary map of the field of public engagement and participation. This map highlights relationships and divergences that exist among diverse forms of practice and brings into clearer view a set of tensions between different contemporary approaches to public engagement and participation. Two ‘frontiers’ of participatory public engagement that socio-cultural researchers should attend are also identified. At the first, scholars need to be critical regarding the particular versions of the public that their preferred approach to engagement and participation supports and concerning how their specific identifications with the public relate to those being addressed across the wider field. At the second frontier, researchers need to consider the possibilities for political intervention that public engagement and participation practice could open out, both in the settings they are already working and also in the much broader, rapidly developing and increasingly complicated contemporary field of public engagement and participation that this article explores

    Why Social Enterprises Are Asking to Be Multi-stakeholder and Deliberative: An Explanation around the Costs of Exclusion.

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    The study of multi-stakeholdership (and multi-stakeholder social enterprises in particular) is only at the start. Entrepreneurial choices which have emerged spontaneously, as well as the first legal frameworks approved in this direction, lack an adequate theoretical support. The debate itself is underdeveloped, as the existing understanding of organisations and their aims resist an inclusive, public interest view of enterprise. Our contribution aims at enriching the thin theoretical reflections on multi-stakeholdership, in a context where they are already established, i.e. that of social and personal services. The aim is to provide an economic justification on why the governance structure and decision-making praxis of the firm needs to account for multiple stakeholders. In particular with our analysis we want: a) to consider production and the role of firms in the context of the “public interest” which may or may not coincide with the non-profit objective; b) to ground the explanation of firm governance and processes upon the nature of production and the interconnections between demand and supply side; c) to explain that the costs associated with multi-stakeholder governance and deliberation in decision-making can increase internal efficiency and be “productive” since they lower internal costs and utilise resources that otherwise would go astray. The key insight of this work is that, differently from major interpretations, property costs should be compared with a more comprehensive range of costs, such as the social costs that emerge when the supply of social and personal services is insufficient or when the identification of aims and means is not shared amongst stakeholders. Our model highlights that when social costs derived from exclusion are high, even an enterprise with costly decisional processes, such as the multistakeholder, can be the most efficient solution amongst other possible alternatives

    Evaluation of the influence of kyphosis and scoliosis on intervertebral disc extrusion in French bulldogs

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    Although thoracic vertebral malformations with kyphosis and scoliosis are often considered incidental findings on diagnostic imaging studies of screw-tailed brachycephalic breeds, they have been suggested to interfere with spinal biomechanics and intervertebral disc degeneration. It is however unknown if an abnormal spinal curvature also predisposes dogs to develop clinically relevant intervertebral disc herniations. The aim of this study was to evaluate if the occurrence of thoracic vertebral malformations, kyphosis or scoliosis would be associated with a higher prevalence of cervical or thoracolumbar intervertebral disc extrusion in French bulldogs
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