Heat flux evaluation in high temperature ring-on-ring contacts

A comprehensive methodology to investigate heat flux in a ring-on-ring tribometer is presented. Thermal fluxes under high contact pressures and temperature differences were evaluated through an experimental campaign and by a numerical procedure of inverse analysis applied to surface temperature measurements. An approximation of a two-dimensional time-dependent analytical solution for the temperature distribution was first developed and subsequently adapted to mimic the specific testing configuration characteristics; the problem was finally simplified to enable further inverse analysis. Experiments were performed using an innovative high temperature ring-on-ring tribometer. The evaluated contact heat transfer rates were reported as a function of normal load and temperature difference between the discs under steady-state conditions; the results reported here show that, in the present test configuration, the temperature difference has stronger influence than the applied load in terms of heat transfer induced by contact

Phase Diagram of the Bose-Hubbard Model with T_3 symmetry

In this paper we study the quantum phase transition between the insulating and the globally coherent superfluid phases in the Bose-Hubbard model with T_3 structure, the "dice lattice". Even in the absence of any frustration the superfluid phase is characterized by modulation of the order parameter on the different sublattices of the T_3 structure. The zero-temperature critical point as a function of a magnetic field shows the characteristic "butterfly" form. At fully frustration the superfluid region is strongly suppressed. In addition, due to the existence of the Aharonov-Bohm cages at f=1/2, we find evidence for the existence of an intermediate insulating phase characterized by a zero superfluid stiffness but finite compressibility. In this intermediate phase bosons are localized due to the external frustration and the topology of the T_3 lattice. We name this new phase the Aharonov-Bohm (AB) insulator. In the presence of charge frustration the phase diagram acquires the typical lobe-structure. The form and hierarchy of the Mott insulating states with fractional fillings, is dictated by the particular topology of the T_3 lattice. The results presented in this paper were obtained by a variety of analytical methods: mean-field and variational techniques to approach the phase boundary from the superconducting side, and a strongly coupled expansion appropriate for the Mott insulating region. In addition we performed Quantum Monte Carlo simulations of the corresponding (2+1)D XY model to corroborate the analytical calculations with a more accurate quantitative analysis. We finally discuss experimental realization of the T_3 lattice both with optical lattices and with Josephson junction arrays.Comment: 16 pages, 17 figure

A continuous population of variable stars up to about 1.5 mag above the horizontal branch?

Increasing samples of pulsating variable stars populating the classical instability strip from the horizontal branch to a few magnitudes brighter are being found in several Local Group galaxies, irrespective of the galaxy morphological type. We will review the observational scenario focusing in particular on the Anomalous Cepheids and related objects.Comment: 5 pages, 2 figures, invited review in JENAM 2003, "Minisymposium: Asteroseismology and Stellar Evolution", Communications in Asteroseismology, in pres

Perceptions about Equity in Public Health: A comparison between frontline staff and informing policy in Ontario

Background: Recent changes in Ontario public health policy call for increased emphasis on equity. However, it is not clear how equity is understood as a concept and how equity is understood as practice. Methods: The aim of this study was to understand public health frontline staff (FLS) perspectives on health equity and how these align with provincial public health policy documents. A qualitative content analysis design was used to examine transcripts from six focus group interviews with frontline public health workers and seven key provincial public health documents that have shaped or influenced public health program planning in Ontario. Perceptions and understandings of health equity in public health were compared. Results: Findings from the study indicate that several areas of alignment exist between how FLS describe equity in public health practice and how equity is addressed in the provincial policy documents; both focus their discussion of equity as relating to the social determinants of health and priority populations. Several differences between FLS perspectives and policy documents were also identified including barriers encountered in FLS daily practice that are not addressed in the provincial policy documents. Conclusions: These alignments and differences provide insights on how FLS incorporate information from provincial policy documents into their practice and suggest the importance of involving FLS in the policy process

Relação entre índices morfométricos de bacias hidrográficas e índices de integridade de floresta ciliar na Bacia do Alto Capivari, Primeiro Planalto Paranaense.

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