Zeolite phi: a physical mixture of chabazite and offretite

Zeolite Phi is synthesized by two methods reported previously. Results from X-ray powder diffraction and scanning electron microscopy suggest that the materials are physical mixtures of chabazite and offretite; one sample has a small amount of phillipsite. The X-ray powder diffraction data from these samples, and those reported previously, are indexed and their unit-cell parameters compare well to those obtained from a physical mixture of chabazite and offretite. These samples show multiple particle morphologies that are indicative of physical mixtures. Zeolite Phi is concluded to be a physical mixture of chabazite and offretite and we suggest that the use of the name zeolite Phi be discontinued

Security policy refinement using data integration: a position paper.

In spite of the wide adoption of policy-based approaches for security management, and many existing treatments of policy verification and analysis, relatively little attention has been paid to policy refinement: the problem of deriving lower-level, runnable policies from higher-level policies, policy goals, and specifications. In this paper we present our initial ideas on this task, using and adapting concepts from data integration. We take a view of policies as governing the performance of an action on a target by a subject, possibly with certain conditions. Transformation rules are applied to these components of a policy in a structured way, in order to translate the policy into more refined terms; the transformation rules we use are similar to those of global-as-view database schema mappings, or to extensions thereof. We illustrate our ideas with an example. Copyright 2009 ACM

A catalogue of velocities in the cluster of galaxies Abell 85

We present a catalogue of velocities for 551 galaxies (and give the coordinates of 39 stars misclassified as galaxies in our photometric plate catalogue) in a region covering about 100'$\times$100' (0.94$\times$0.94 Mpc for an average redshift of 0.0555, assuming H$_\circ$=50 km s$^{-1}$ Mpc$^{-1}$) in the direction of the rich cluster Abell 85. This catalogue includes previously published redshifts by Beers et al. (1991) and Malumuth et al. (1992), together with our 367 new measurements. A total of 305 galaxies have velocities in the interval 13350-20000 km s$^{-1}$, and will be considered as members of the cluster. Abell 85 therefore becomes one of the clusters with the highest number of measured redshifts; its optical properties are being investigated in a companion paper.Comment: Accepted for publication in A&AS, Table 4 available in electronic form onl

Metric-affine f(R,T) theories of gravity and their applications

We study f(R,T) theories of gravity, where T is the trace of the energy-momentum tensor T_{\mu\nu}, with independent metric and affine connection (metric-affine theories). We find that the resulting field equations share a close resemblance with their metric-affine f(R) relatives once an effective energy-momentum tensor is introduced. As a result, the metric field equations are second-order and no new propagating degrees of freedom arise as compared to GR, which contrasts with the metric formulation of these theories, where a dynamical scalar degree of freedom is present. Analogously to its metric counterpart, the field equations impose the non-conservation of the energy-momentum tensor, which implies non-geodesic motion and consequently leads to the appearance of an extra force. The weak field limit leads to a modified Poisson equation formally identical to that found in Eddington-inspired Born-Infeld gravity. Furthermore, the coupling of these gravity theories to perfect fluids, electromagnetic, and scalar fields, and their potential applications are discussed.Comment: 9 page

p-Wave Polaron

We consider the properties of a single impurity immersed in a Fermi sea close to an interspecies p-wave Feshbach resonance. We calculate its dispersion and spectral response to a radiofrequency pulse. In the presence of a magnetic field, dipolar interactions split the resonance and lead to the appearance of two novel features with respect to the s-wave case: a third polaron branch in the excitation spectrum, in addition to the usual attractive and repulsive ones; and an anisotropic dispersion of the impurity characterized by different effective masses perpendicular and parallel to the magnetic field. The anisotropy can be tuned as a function of the field strength and the two effective masses may have opposite signs, or become smaller than the bare mass

Scalar GW detection with a hollow spherical antenna

We study the response and cross sections for the absorption of GW energy in a Jordan-Brans-Dicke theory by a resonant mass detector shaped as a hollow sphere.Comment: latex file, 9 page