2,153 research outputs found

    Design of an MgB<sub>2 </sub>race track coil for a wind generator pole demonstration

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    An MgB2 race track coil intended for demonstrating a down scaled pole of a 10 MW direct drive wind turbine generator has been designed. The coil consists of 10 double pancake coils stacked into a race track coil with a cross section of 84 mm x 80 mm. The length of the straight section is 0.5 m and the diameter of the end sections is 0.3 m. Expanded to a straight section of 3.1 m it will produce about 1.5 T magnetic flux density in the air gap of the 10 MW 32 pole generator and about 3.0 T at the edge of the superconducting coil with an operation current density of the coil of 70 A/mm2.Electrical Sustainable EnergyElectrical Engineering, Mathematics and Computer Scienc

    Drones and digital adherence monitoring for community-based tuberculosis control in remote Madagascar: a cost-effectiveness analysis

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    Continuing tuberculosis control with current approaches is unlikely to reach the World Health Organization's objective to eliminate TB by 2035. Innovative interventions such as unmanned aerial vehicles (or drones) and digital adherence monitoring technologies have the potential to enhance patient-centric quality tuberculosis care and help challenged National Tuberculosis Programs leapfrog over the impediments of conventional Directly Observed Therapy (DOTS) implementation. A bundle of innovative interventions referred to for its delivery technology as the Drone Observed Therapy System (DrOTS) was implemented in remote Madagascar. Given the potentially increased cost these interventions represent for health systems, a cost-effectiveness analysis was indicated.; A decision analysis model was created to calculate the incremental cost-effectiveness of the DrOTS strategy compared to DOTS, the standard of care, in a study population of 200,000 inhabitants in rural Madagascar with tuberculosis disease prevalence of 250/100,000. A mixed top-down and bottom-up costing approach was used to identify costs associated with both models, and net costs were calculated accounting for resulting TB treatment costs. Net cost per disability-adjusted life years averted was calculated. Sensitivity analyses were performed for key input variables to identify main drivers of health and cost outcomes, and cost-effectiveness.; Net cost per TB patient identified within DOTS and DrOTS were, respectively, 282and282 and 1,172. The incremental cost per additional TB patient diagnosed in DrOTS was 2,631andtheincrementalcost−effectivenessratioofDrOTScomparedtoDOTSwas2,631 and the incremental cost-effectiveness ratio of DrOTS compared to DOTS was 177 per DALY averted. Analyses suggest that integrating drones with interventions ensuring highly sensitive laboratory testing and high treatment adherence optimizes cost-effectiveness.; Innovative technology packages including drones, digital adherence monitoring technologies, and molecular diagnostics for TB case finding and retention within the cascade of care can be cost effective. Their integration with other interventions within health systems may further lower costs and support access to universal health coverage

    Dielectrophoresis-Driven Spreading of Immersed Liquid Droplets

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    In recent years electrowetting-on-dielectric (EWOD) has become an effective tool to control partial wetting. EWOD uses the liquid−solid interface as part of a capacitive structure that allows capacitive and interfacial energies to adjust by changes in wetting when the liquid−solid interface is charged due to an applied voltage. An important aspect of EWOD has been its applications in micro fluidics in chemistry and biology and in optical devices and displays in physics and engineering. Many of these rely on the use of a liquid droplet immersed in a second liquid due to the need either for neutral buoyancy to overcome gravity and shield against impact shocks or to encapsulate the droplet for other reasons, such as in microfluidic-based DNA analyses. Recently, it has been shown that nonwetting oleophobic surfaces can be forcibly wetted by nonconducting oils using nonuniform electric fields and an interface-localized form of liquid dielectrophoresis (dielectrowetting). Here we show that this effect can be used to create films of oil immersed in a second immiscible fluid of lower permittivity. We predict that the square of the thickness of the film should obey a simple law dependent on the square of the applied voltage and with strength dependent on the ratio of difference in permittivity to the liquid-fluid interfacial tension, Δε/γLF. This relationship is experimentally confirmed for 11 liquid−air and liquid−liquid combinations with Δε/γLF having a span of more than two orders of magnitude. We therefore provide fundamental understanding of dielectrowetting for liquid-in-liquid systems and also open up a new method to determine liquid−liquid interfacial tensions

    Synthesis of Alkaline Earth Diazenides MAEN2 (MAE = Ca, Sr, Ba) by Controlled Thermal Decomposition of Azides under High Pressure

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    The alkaline earth diazenides MAEN2 with MAE = Ca, Sr and Ba were synthesized by a novel synthetic approach, namely, a controlled decomposition of the corresponding azides in a multianvil press at highpressure/ high-temperature conditions. The crystal structure of hitherto unknown calcium diazenide (space group I4/mmm (no. 139), a = 3.5747(6) Å, c = 5.9844(9) Å, Z = 2, wRp = 0.078) was solved and refined on the basis of powder X-ray diffraction data as well as that of SrN2 and BaN2. Accordingly, CaN2 is isotypic with SrN2 (space group I4/mmm (no. 139), a = 3.8054(2) Å, c = 6.8961(4) Å, Z = 2, wRp = 0.057) and the corresponding alkaline earth acetylenides (MAEC2) crystallizing in a tetragonally distorted NaCl structure type. In accordance with literature data, BaN2 adopts a more distorted structure in space group C2/c (no. 15) with a = 7.1608(4) Å, b = 4.3776(3) Å, c = 7.2188(4) Å, β = 104.9679(33)°, Z = 4 and wRp = 0.049). The N−N bond lengths of 1.202(4) Å in CaN2 (SrN2 1.239(4) Å, BaN2 1.23(2) Å) correspond well with a double-bonded dinitrogen unit confirming a diazenide ion [N2]2−. Temperature-dependent in situ powder X-ray diffractometry of the three alkaline earth diazenides resulted in formation of the corresponding subnitrides MAE2N (MAE = Ca, Sr, Ba) at higher temperatures. FTIR spectroscopy revealed a band at about 1380 cm−1 assigned to the N−N stretching vibration of the diazenide unit. Electronic structure calculations support the metallic character of alkaline earth diazenides

    Phoretic Motion of Spheroidal Particles Due To Self-Generated Solute Gradients

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    We study theoretically the phoretic motion of a spheroidal particle, which generates solute gradients in the surrounding unbounded solvent via chemical reactions active on its surface in a cap-like region centered at one of the poles of the particle. We derive, within the constraints of the mapping to classical diffusio-phoresis, an analytical expression for the phoretic velocity of such an object. This allows us to analyze in detail the dependence of the velocity on the aspect ratio of the polar and the equatorial diameters of the particle and on the fraction of the particle surface contributing to the chemical reaction. The particular cases of a sphere and of an approximation for a needle-like particle, which are the most common shapes employed in experimental realizations of such self-propelled objects, are obtained from the general solution in the limits that the aspect ratio approaches one or becomes very large, respectively.Comment: 18 pages, 5 figures, to appear in European Physical Journal

    Access, participation and capabilities: Theorising the contribution of university bursaries to students’ well-being, flourishing and success

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    For the last 10 years, universities in England have been expected to offer financial support to low-income students alongside that provided by government. These bursaries were initially conceived in terms of improving access for under-represented groups, but attention has turned to their role in supporting student retention and success. This paper reports on two qualitative studies undertaken by contrasting universities that have been brought together due to their complementary findings. Semi-structured interviews were undertaken with a total of 98 students. Students’ views on bursaries and how they impact on their lives are reported and used to develop a descriptive model of the web of choices that students have in balancing finances and time. This is contextualised within Sen’s ‘capabilities approach’, to argue that providing access to higher education is insufficient if disadvantaged students are not able to flourish by participating fully in the university experience

    The sedimentation of an institution: changing governance in UK financial services

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    Post-print version. Final version published by Sage; available online at http://jmi.sagepub.com/The Financial Services Act (FSA) 1986 was the first comprehensive attempt to create a unified statutorily based system of regulation within the UK financial sector. It generated a framework of regulation that is in a continuous state of development and modification. In this paper we study the development of UK financial regulation between 1986 and 2011. We trace how competing theorizations and logics of regulation have led to the institutionalization of a meta-form of financial regulation. In doing so, we address the conundrum of conscious, strategic theorizations leading to cognitive taken-for-granted institutions by identifying four catalysts that contribute to institutionalization when concurring with theorization. These are: the evocation of political ideologies, the appropriation of scandals, the growing number of actors and the increasing organization of actors. Finally, we argue that sedimentation is the appropriate metaphor for the version of institutionalization occurring in this setting

    Maturation of the Language Network: From Inter- to Intrahemispheric Connectivities

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    Language development must go hand-in-hand with brain maturation. Little is known about how the brain develops to serve language processing, in particular, the processing of complex syntax, a capacity unique to humans. Behavioral reports indicate that the ability to process complex syntax is not yet adult-like by the age of seven years. Here, we apply a novel method to demonstrate that the basic neural basis of language, as revealed by low frequency fluctuation stemming from functional MRI data, differs between six-year-old children and adults in crucial aspects. Although the classical language regions are actively in place by the age of six, the functional connectivity between these regions clearly is not. In contrast to adults who show strong connectivities between frontal and temporal language regions within the left hemisphere, children's default language network is characterized by a strong functional interhemispheric connectivity, mainly between the superior temporal regions. These data indicate a functional reorganization of the neural network underlying language development towards a system that allows a close interplay between frontal and temporal regions within the left hemisphere
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