Effects of Pore Walls and Randomness on Phase Transitions in Porous Media

We study spin models within the mean field approximation to elucidate the topology of the phase diagrams of systems modeling the liquid-vapor transition and the separation of He$^3$--He$^4$ mixtures in periodic porous media. These topologies are found to be identical to those of the corresponding random field and random anisotropy spin systems with a bimodal distribution of the randomness. Our results suggest that the presence of walls (periodic or otherwise) are a key factor determining the nature of the phase diagram in porous media.Comment: REVTeX, 11 eps figures, to appear in Phys. Rev.

Superconductivity and single crystal growth of Ni0:05TaS2

Superconductivity was discovered in a Ni0:05TaS2 single crystal. A Ni0:05TaS2 single crystal was successfully grown via the NaCl/KCl flux method. The obtained lattice constant c of Ni0:05TaS2 is 1.1999 nm, which is significantly smaller than that of 2H-TaS2 (1.208 nm). Electrical resistivity and magnetization measurements reveal that the superconductivity transition temperature of Ni0:05TaS2 is enhanced from 0.8 K (2H-TaS2) to 3.9 K. The charge-density-wave transition of the matrix compound 2H-TaS2 is suppressed in Ni0:05TaS2. The success of Ni0:05TaS2 single crystal growth via a NaCl/KCl flux demonstrates that NaCl/KCl flux method will be a feasible method for single crystal growth of the layered transition metal dichalcogenides.Comment: 13pages, 6 figures, Published in SS

Some Applications of the Extended Bendixson-Dulac Theorem

During the last years the authors have studied the number of limit cycles of several families of planar vector fields. The common tool has been the use of an extended version of the celebrated Bendixson-Dulac Theorem. The aim of this work is to present an unified approach of some of these results, together with their corresponding proofs. We also provide several applications.Comment: 19 pages, 3 figure

Access to Print in Low‐Income and Middle‐Income Communities: An Ecological Study of Four Neighborhoods

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88026/1/RRQ.36.1.1.pd

A Gravitational Aharonov-Bohm Effect, and its Connection to Parametric Oscillators and Gravitational Radiation

A thought experiment is proposed to demonstrate the existence of a gravitational, vector Aharonov-Bohm effect. A connection is made between the gravitational, vector Aharonov-Bohm effect and the principle of local gauge invariance for nonrelativistic quantum matter interacting with weak gravitational fields. The compensating vector fields that are necessitated by this local gauge principle are shown to be incorporated by the DeWitt minimal coupling rule. The nonrelativistic Hamiltonian for weak, time-independent fields interacting with quantum matter is then extended to time-dependent fields, and applied to problem of the interaction of radiation with macroscopically coherent quantum systems, including the problem of gravitational radiation interacting with superconductors. But first we examine the interaction of EM radiation with superconductors in a parametric oscillator consisting of a superconducting wire placed at the center of a high Q superconducting cavity driven by pump microwaves. We find that the threshold for parametric oscillation for EM microwave generation is much lower for the separated configuration than the unseparated one, which then leads to an observable dynamical Casimir effect. We speculate that a separated parametric oscillator for generating coherent GR microwaves could also be built.Comment: 25 pages, 5 figures, YA80 conference (Chapman University, 2012

Isotopic and spin selectivity of H_2 adsorbed in bundles of carbon nanotubes

Due to its large surface area and strongly attractive potential, a bundle of carbon nanotubes is an ideal substrate material for gas storage. In addition, adsorption in nanotubes can be exploited in order to separate the components of a mixture. In this paper, we investigate the preferential adsorption of D_2 versus H_2(isotope selectivity) and of ortho versus para(spin selectivity) molecules confined in the one-dimensional grooves and interstitial channels of carbon nanotube bundles. We perform selectivity calculations in the low coverage regime, neglecting interactions between adsorbate molecules. We find substantial spin selectivity for a range of temperatures up to 100 K, and even greater isotope selectivity for an extended range of temperatures,up to 300 K. This isotope selectivity is consistent with recent experimental data, which exhibit a large difference between the isosteric heats of D_2 and H_2 adsorbed in these bundles.Comment: Paper submitted to Phys.Rev. B; 17 pages, 2 tables, 6 figure

Alcohol consumption and perceptions of health risks during COVID-19: a qualitative study of middle-aged women in South Australia

Australian women's alcohol consumption has increased in frequency during COVID-19. Research suggests this is to cope with stress resulting from the pandemic and COVID-19 countermeasures that require social distancing. This is a critical public health concern because increased alcohol consumption, even for a short period, increases the myriad longer-term health risks associated with cumulative exposure to alcohol. This paper provides unique qualitative evidence of how health risk perceptions are re-focused toward the shorter-term during the pandemic, through analysis of interviews with 40 middle-aged Australian women (aged 45–64) representing a range of self-perceived drinking status' (“occasional”/“light”/“moderate”/“heavy”) before and then during the pandemic (n = 80 interviews). Our analysis captures women's risk horizons drifting away from the uncertain longer-term during COVID-19, toward the immediate need to “get through” the pandemic. We show how COVID-19 has increased the perceived value of consuming alcohol among women, particularly when weighed up against the social and emotional “costs” of reducing consumption. Our findings have implications for the delivery of alcohol-related health risk messages designed for middle-aged women both during, and into the recovery phases of the pandemic, who already consume more alcohol and experience more alcohol-related health risk than women in other age groups.Belinda Lunnay, Kristen Foley, Samantha B. Meyer, Megan Warin, Carlene Wilson, Ian Olver ... et al

Social class and changes in Australian women's affect and alcohol consumption during COVID-19

Introduction: Before the pandemic, mid-life women in Australia were among the “heaviest” female alcohol consumers, giving rise to myriad preventable health risks. This paper uses an innovative model of social class within a sample of Australian women to describe changes in affective states and alcohol consumption patterns across two time points during COVID-19. Methods: Survey data were collected from Australian mid-life women (45–64 years) at two time points during COVID-19—May 2020 (N = 1,218) and July 2020 (N = 799). We used a multi-dimensional model for measuring social class across three domains—economic capital (income, property and assets), social capital (social contacts and occupational prestige of those known socially), and cultural capital (level of participation in various cultural activities). Latent class analysis allowed comparisons across social classes to changes in affective states and alcohol consumption patterns reported at the two time points using alcohol consumption patterns as measured by the Alcohol Use Disorders Identification Test—Consumption (AUDIT-C) and its component items. Results: Seven social classes were constructed, characterized by variations in access to capital. Affective states during COVID-19 differed according to social class. Comparing between the survey time points, feeling fearful/anxious was higher in those with high economic and cultural capital and moderate social capital (“emerging affluent”). Increased depression was most prominent in the class characterized by the highest volumes of all forms of capital (“established affluent”). The social class characterized by the least capital (“working class”) reported increased prevalence of uncertainty, but less so for feeling fearful or anxious, or depressed. Women's alcohol consumption patterns changed across time during the pandemic. The “new middle” class—a group characterized by high social capital (but contacts with low prestige) and minimal economic capital—had increased AUDIT-C scores. Conclusion: Our data shows the pandemic impacted women's negative affective states, but not in uniform ways according to class. It may explain increases in alcohol consumption among women in the emerging affluent group who experienced increased feelings or fear and anxiety during the pandemic. This nuanced understanding of the vulnerabilities of sub-groups of women, in respect to negative affect and alcohol consumption can inform future pandemic policy responses designed to improve mental health and reduce the problematic use of alcohol. Designing pandemic responses segmented for specific audiences is also aided by our multi-dimensional analysis of social class, which uncovers intricate differences in affective states amongst sub-groups of mid-life women.Belinda Lunnay, Barbara Toson, Carlene Wilson, Emma R. Miller, Samantha Beth Meyer, Ian N. Olver, Kristen Foley, Jessica A. Thomas and Paul Russell War