Spin-polarized stable phases of the 2-D electron fluid at finite temperatures

The Helmholtz free energy F of the interacting 2-D electron fluid is calculated nonperturbatively using a mapping of the quantum fluid to a classical Coulomb fluid [Phys. Rev. Letters, vol. 87, 206404 (2001)]. For density parameters rs such that rs<~25, the fluid is unpolarized at all temperatures t=T/EF where EF is the Fermi energy. For lower densities, the system becomes fully spin polarized for t<~0.35, and partially polarized for 0.35<t< 2, depending on the density. At rs ~25-30, and t ~0.35, an ''ambispin'' phase where F is almost independent of the spin polarization is found. These results support recent claims, based on quantum Monte Carlo results, for a stable, fully spin-polarized fluid phase at T = 0 for rs larger than about 25-26.Comment: Latex manuscript (4-5 pages) and two postscript figures; see also http://nrcphy1.phy.nrc.ca/ims/qp/chandre/chnc

Overview of Kyoto Fusioneering’s SCYLLA© (“Self-Cooled Yuryo Lithium-Lead Advanced”) Blanket for Commercial Fusion Reactors

This article outlines Kyoto Fusioneering’s (KF’s) initial engineering and development activities for its self-cooled lithium lead-type blanket: Self-Cooled Yuryo Lithium-Lead Advanced (SCYLLA©). We provide details on overall design, including an initial tritium breeding ratio (TBR) assessment via neutronics analysis, as well as the status of SCYLLA©-relevant R&D. This includes silicon carbide composite (SiCf/SiC) manufacturing techniques, tritium extraction, materials compatibility, and heat transfer, which are being explored via collaboration with Kyoto University. Results of previous work in relation to this R&D are presented. Permeability coefficients indicate a promising property of SiCf/SiC tritium hermeticity at high temperatures. Tritium extraction technology via vacuum sieve tray (VST) is shown to be demonstrated at engineering scale. A local TBR of up to 1.4 can be achieved with the SCYLLA© configuration. Fabrication methods for various SiCf/SiC components including the blanket module, heat exchanger, and flow path components are provided. A tritium compatible high-temperature SiCf/SiC heat exchanger is discussed. Commercial viability and reactor adaptability are considered as a theme throughout. Finally, KF’s plans to build a facility for demonstration reactor relevant testing of a SCYLLA© prototype in the mid-2020s, which will provide a significant step toward commercial fusion energy, are presented

Applying a research ethics review processes in rural practice-based research

Introduction: Partnering with rural primary care in practice-based research allows researchers access to a vital segment of the health care sector and a window into some of the most vulnerable, high-risk, high-need patient populations. The readiness for rural primary care to fully embrace research partnerships, however, is often tempered by ethical questions in conducting research in close-knit settings. This research provides practices with a refined decision support tool for evaluating the fit of research opportunities for their unique practices. Materials and Methods: A two-phase effort was conducted to glean insight from currently available literature on ethical considerations in practice-based research and augment this information by consulting with state-based subject matter experts. Qualitative data were gathered through semi-structured interviews with key stakeholders at each of the West Virginia medical schools. Results: The literature clearly acknowledges the need to ensure ethical standards in practice-based research – from the standpoints of the clinician and the researcher. The need to ensure comprehensive, culturally appropriate institutional review board approval is essential in developing and safeguarding participants. From discussions with subject matter experts, we find complementary guidance. However, tempering this sentiment is an overall caution of the unique role of rural primary care in representing and protecting the needs of the community. Five fundamental cautions regarding the conduct of practice-based research in rural settings are here identified, spanning the protection of individual patients, their communities, and clinicians. Discussion: Findings from this study can support and empower primary care clinicians and practices, especially those in rural and close-knit communities, to address essential considerations in practice-based research. Results allow for framing of a refined decision support tool for primary care practices and clinicians to use in evaluating the fit of research opportunities for their unique practices, instilling a sense of shared power in the research process by better equipping primary care to proactively engage in substantive dialogue with research partners

Applying a research ethics review processes in rural practice-based research

Introduction: Partnering with rural primary care in practice-based research allows researchers access to a vital segment of the health care sector and a window into some of the most vulnerable, high-risk, high-need patient populations. The readiness for rural primary care to fully embrace research partnerships, however, is often tempered by ethical questions in conducting research in close-knit settings. This research provides practices with a refined decision support tool for evaluating the fit of research opportunities for their unique practices. Materials and Methods: A two-phase effort was conducted to glean insight from currently available literature on ethical considerations in practice-based research and augment this information by consulting with state-based subject matter experts. Qualitative data were gathered through semi-structured interviews with key stakeholders at each of the West Virginia medical schools. Results: The literature clearly acknowledges the need to ensure ethical standards in practice-based research – from the standpoints of the clinician and the researcher. The need to ensure comprehensive, culturally appropriate institutional review board approval is essential in developing and safeguarding participants. From discussions with subject matter experts, we find complementary guidance. However, tempering this sentiment is an overall caution of the unique role of rural primary care in representing and protecting the needs of the community. Five fundamental cautions regarding the conduct of practice-based research in rural settings are here identified, spanning the protection of individual patients, their communities, and clinicians. Discussion: Findings from this study can support and empower primary care clinicians and practices, especially those in rural and close-knit communities, to address essential considerations in practice-based research. Results allow for framing of a refined decision support tool for primary care practices and clinicians to use in evaluating the fit of research opportunities for their unique practices, instilling a sense of shared power in the research process by better equipping primary care to proactively engage in substantive dialogue with research partners

Untersuchungen des BÖL-Verbundprojektes zur Kupferminimierung im ökologischen Weinbau

The development of sustainable and economically feasible strategies to get an effec-tual control of downy mildew on grapes (Plasmopara viticola) with less than 3 kg/(ha*a) of copper to avoid further environmental risks is the intention of this project. Due to harmful effects on the natural environment, copper applications are under considera-tion. Therefore, in this four-year-project first of all test products are screened under greenhouse conditions on potted vines. Thereafter the best test agents are studied in organically managed test vineyards. Finally the selected strategies are tested under practical conditions on organically managed vineyards. Beyond these examinations a close link between wineries and research is given by SME and consultant partners. The results indicate that plant extracts, finely ground stones and new copper formula-tions could probably serve as plant resistance improvers and plant protection prod-ucts, respectively, to prevent attacks of P. viticola. Moreover, it was possible to select prosperous agents and strategies for the growing period 2007. These were agents of the substance categories “new copper formulations”, “plant extracts” and “finely ground stones”. Regarding the results of three growing periods, the project will provide effective and economically feasible alternatives for copper applications in order to deliver sustainable approaches for P. viticola control in practise

Measuring the equation of state of a hard-disc fluid

We use video microscopy to study a two-dimensional (2D) model fluid of charged colloidal particles suspended in water and compute the pressure from the measured particle configurations. Direct experimental control over the particle density by means of optical tweezers allows the precise measurement of pressure as a function of density. We compare our data with theoretical predictions for the equation of state, the pair-correlation function and the compressibility of a hard-disc fluid and find good agreement, both for the fluid and the solid phase. In particular the location of the transition point agrees well with results from Monte Carlo simulations.Comment: 7 pages, to appear in EPL, slightly corrected versio

Non-volatile switching in graphene field effect devices

The absence of a band gap in graphene restricts its straight forward application as a channel material in field effect transistors. In this letter, we report on a new approach to engineer a band gap in graphene field effect devices (FED) by controlled structural modification of the graphene channel itself. The conductance in the FEDs is switched between a conductive "on-state" to an insulating "off-state" with more than six orders of magnitude difference in conductance. Above a critical value of an electric field applied to the FED gate under certain environmental conditions, a chemical modification takes place to form insulating graphene derivatives. The effect can be reversed by electrical fields of opposite polarity or short current pulses to recover the initial state. These reversible switches could potentially be applied to non-volatile memories and novel neuromorphic processing concepts.Comment: 14 pages, 4 figures, submitted to IEEE ED

Dimensional crossover of the fundamental-measure functional for parallel hard cubes

We present a regularization of the recently proposed fundamental-measure functional for a mixture of parallel hard cubes. The regularized functional is shown to have right dimensional crossovers to any smaller dimension, thus allowing to use it to study highly inhomogeneous phases (such as the solid phase). Furthermore, it is shown how the functional of the slightly more general model of parallel hard parallelepipeds can be obtained using the zero-dimensional functional as a generating functional. The multicomponent version of the latter system is also given, and it is suggested how to reformulate it as a restricted-orientation model for liquid crystals. Finally, the method is further extended to build a functional for a mixture of parallel hard cylinders.Comment: 4 pages, no figures, uses revtex style files and multicol.sty, for a PostScript version see http://dulcinea.uc3m.es/users/cuesta/cross.p

Transport Coefficients of the Yukawa One Component Plasma

We present equilibrium molecular-dynamics computations of the thermal conductivity and the two viscosities of the Yukawa one-component plasma. The simulations were performed within periodic boundary conditions and Ewald sums were implemented for the potentials, the forces, and for all the currents which enter the Kubo formulas. For large values of the screening parameter, our estimates of the shear viscosity and the thermal conductivity are in good agreement with the predictions of the Chapman-Enskog theory.Comment: 11 pages, 2 figure