Transverse microcracking in Celion 6000/PMR-15 graphite-polyimide

The effects of room temperature tensile loading and five thermal loadings, in the range -320 F (-196C) to 625F (330CC), upon the development of transverse microcracks (TVM) in Celion 6000/PMR-15 graphite-polyimide laminates were investigated. Microcracks were observed using a replicating technique, microscopy and X-ray. The mechanical or thermal load at which microcracking initiates and the ply residual stresses were predicted using laminate analysis with stress- and temperature-dependent material properties

A Roadmap for Change: Federal Policy Recommendations for Addressing the Criminilization of LGBT People and People Living with HIV

Each year in the United States, thousands of lesbian, gay, bisexual, transgender, Two Spirit, queer, questioning and gender non-conforming (LGBT) people and people living with HIV come in contact with the criminal justice system and fall victim to similar miscarriages of justice.According to a recent national study, a startling 73% of all LGBT people and PLWH surveyed have had face-to-face contact with police during the past five years.1 Five percent of these respondents also report having spent time in jail or prison, a rate that is markedly higher than the nearly 3% of the U.S. adult population whoare under some form of correctional supervision (jail, prison, probation, or parole) at any point in time.In fact, LGBT people and PLWH, especially Native and LGBT people and PLWH of color, aresignificantly overrepresented in all aspects of the penal system, from policing, to adjudication,to incarceration. Yet their experiences are often overlooked, and little headway has been madein dismantling the cycles of criminalization that perpetuate poor life outcomes and push already vulnerable populations to the margins of society.The disproportionate rate of LGBT people and PLWH in the criminal system can best be understoodin the larger context of widespread and continuing discrimination in employment, education, socialservices, health care, and responses to violence

Epitaxial Ferromagnetic Nanoislands of Cubic GdN in Hexagonal GaN

Periodic structures of GdN particles encapsulated in a single crystalline GaN matrix were prepared by plasma assisted molecular beam epitaxy. High resolution X-ray diffractometery shows that GdN islands, with rock salt structure are epitaxially oriented to the wurtzite GaN matrix. Scanning transmission electron microscopy combined with in-situ reflection high energy electron diffraction allows for the study of island formation dynamics, which occurs after 1.2 monolayers of GdN coverage. Magnetometry reveals two ferromagnetic phases, one due to GdN particles with Curie temperature of 70K and a second, anomalous room temperature phase.Comment: 4 pages, 3 figure

Quantum ratchet transport with minimal dispersion rate

We analyze the performance of quantum ratchets by considering the dynamics of an initially localized wave packet loaded into a flashing periodic potential. The directed center-of-mass motion can be initiated by the uniform modulation of the potential height, provided that the modulation protocol breaks all relevant time- and spatial reflection symmetries. A poor performance of quantum ratchet transport is characterized by a slow net motion and a fast diffusive spreading of the wave packet, while the desirable optimal performance is the contrary. By invoking a quantum analog of the classical P\'eclet number, namely the quotient of the group velocity and the dispersion of the propagating wave packet, we calibrate the transport properties of flashing quantum ratchets and discuss the mechanisms that yield low-dispersive directed transport.Comment: 6 pages; 3 figures; 1 tabl

Predictors of tonsillectomy after previous adenoidectomy for upper airway obstruction [abstract]

One of the main indications for adenotonsillectomy in children is upper airway obstruction, including obstructive sleep apnea. Previous research has suggested an increased risk for requiring subsequent tonsillectomy when adenoidectomy alone is performed for upper airway obstruction. The purpose of this study is to further characterize potential risk factors for subsequent tonsillectomy in pediatric patients undergoing adenoidectomy for upper airway obstruction

A Better Definition of the Kilogram

This article reviews several recent proposed redefinitions of the kilogram, and compares them with respect to practical realizations, uncertainties (estimated standard deviations), and educational aspects.Comment: 10 pages, no figure