Surface Roughness Effect on Fatigue Life Preditions under Cumulative Damage

The influence of surface roughness parameter on the fatigue life is studied using rotory bending loading under room temperature and zero mean stress (R=-1). Three levels of average surface roughness (Ra), namely smooth, medium and rough, are considered. For the above three levels, three equations which describe the S-N curve are established. The application of these equations to specimens tested under cumulative fatigue damage shows that the roughness parameter must not be ignored. Hence a new model considering this parameter is formulated which may take the form From the applications of the proposed model, it is concluded that fatigue life predictions are in good agreement with the experimental results

Classical rotational inertia of solid helium 4

The observation of reduced rotational inertia in a cell containing solid helium 4 has been interpreted as evidence for superfluidity of the solid. An alternative explanation is slippage of the solid at the container wall due to grain boundary premelting between the solid and dense adsorbed layers at the container wall. We calculate the range of film thickness and the viscous drag, and find that the slippage can account for the observations.Comment: 4 pages, 1 figur

Boston Hospitality Review: Fall 2016

The Heart of Successful Hotels: Going Beyond the Monopoly Game Strategy By Joseph Khairallah and Andrea Foster -- Fragments of the Past By Peter Szende and Annie Holcombe -- Hospitality Branding in the Age of the Millennial By Allen Adamson and Chekitan S. Dev -- In 2017 What Will a Restaurant Actually Be? A New Taxonomy By Christopher Muller -- The Unreal Thing: Faux Heritage at Disney By Bradford Hudson -- An Insider’s Look at the 2016 Philadelphia Democratic National Convention: Hospitality and Inclusion at Work By Erin Tucker, Leora Halpern Lanz, and Juan Lesme

Developmental and Degenerative Cardiac Defects in the Taiwanese Mouse Model of Severe Spinal Muscular Atrophy

We would like to acknowledge the Microscopy and Histology Core Facility at the University of Aberdeen, Kevin Mackenzie, Debbie Wilkinson, Gillian Milne and Lucy Wight, for the use of their facilities. G.K.M. was funded by a research award from RGA awarded to S.H.P. E.S. was funded by a University of Aberdeen Elphinstone PhD Studentship and a research award from the Euan Macdonald Centre for Motor Neurone Disease Research. H.K.S. was funded by a Euan Macdonald Centre for Motor Neurone Disease Research PhD Studentship. S.H.P. is funded by Tenovus (Scotland), SMA Trust and Prinses Beatrix Spierfonds. T.H.G. is funded by SMA Trust (UK SMA Research Consortium Award), Muscular Dystrophy UK, and Anatomical Society (PhD Studentship).Peer reviewedPostprin

Search for supersolidity in 4He in low-frequency sound experiments

We present results of the search for supersolid 4He using low-frequency, low-level mechanical excitation of a solid sample grown and cooled at fixed volume. We have observed low frequency non-linear resonances that constitute anomalous features. These features, which appear below about 0.8 K, are absent in 3He. The frequency, the amplitude at which the nonlinearity sets in, and the upper temperature limit of existence of these resonances depend markedly on the sample history.Comment: Submitted to the Quantum Fluids and Solids Conf. Aug. 2006 Kyot

Tissue Adaptations of Memory and Tissue-Resident Gamma Delta T Cells

Epithelial and mucosal barriers are critical interfaces physically separating the body from the outside environment and are the tissues most exposed to microorganisms and potential inflammatory agents. The integrity of these tissues requires fine tuning of the local immune system to enable the efficient elimination of invasive pathogens while simultaneously preserving a beneficial relationship with commensal organisms and preventing autoimmunity. Although they only represent a small fraction of circulating and lymphoid T cells, γδ T cells form a substantial population at barrier sites and even outnumber conventional αβ T cells in some tissues. After their egress from the thymus, several γδ T cell subsets naturally establish residency in predetermined mucosal and epithelial locations, as exemplified by the restricted location of murine Vγ5+ and Vγ3Vδ1+ T cell subsets to the intestinal epithelium and epidermis, respectively. Because of their preferential location in barrier sites, γδ T cells are often directly or indirectly influenced by the microbiota or the pathogens that invade these sites. More recently, a growing body of studies have shown that γδ T cells form long-lived memory populations upon local inflammation or bacterial infection, some of which permanently populate the affected tissues after pathogen clearance or resolution of inflammation. Natural and induced resident γδ T cells have been implicated in many beneficial processes such as tissue homeostasis and pathogen control, but their presence may also exacerbate local inflammation under certain circumstances. Further understanding of the biology and role of these unconventional resident T cells in homeostasis and disease may shed light on potentially novel vaccines and therapies

Solidification of small para-H2 clusters at zero temperature

We have determined the ground-state energies of para-H$_2$ clusters at zero temperature using the diffusion Monte Carlo method. The liquid or solid character of each cluster is investigated by restricting the phase through the use of proper importance sampling. Our results show inhomogeneous crystallization of clusters, with alternating behavior between liquid and solid phases up to N=55. From there on, all clusters are solid. The ground-state energies in the range N=13--75 are established and the stable phase of each cluster is determined. In spite of the small differences observed between the energy of liquid and solid clusters, the corresponding density profiles are significantly different, feature that can help to solve ambiguities in the determination of the specific phase of H$_2$ clusters.Comment: 17 pages, accepted for publication in J. Phys. Chem.

Crack Growth Model for Estimating the Fatigue Life under Variable loading

This paper examines the fatigue short and long cracks behaviour in 2024 T4 aluminum alloy under rotating bending loading and stress ratio R = -1. In the short cracks region, cracks grow initially at a fast rate but deceleration occurs quickly and, depending on the stress level, they either arrest or are temporarily halted at a critical length. This critical length is shown to conincide with the value of the microstructure parameter, grain size diameter, An empirical model which describes short and long cracks rates is developed and is seen in good agreement with the experimental observations in this alloy. Comparison of the empirical model lives results with cumulative fatigue results has shown encouraging experimentally agreement while liner rule gave a non – reasonable prediction