Quantum diffusion on a cyclic one dimensional lattice

The quantum diffusion of a particle in an initially localized state on a cyclic lattice with N sites is studied. Diffusion and reconstruction time are calculated. Strong differences are found for even or odd number of sites and the limit N->infinit is studied. The predictions of the model could be tested with micro - and nanotechnology devices.Comment: 17 pages, 5 figure

Relationship between the pressure at the casing wall and at the blade tip for a vibrating turbine blade

A recent research program has identified the possibility of using the analysis of casing wall pressures in the indirect measurement of gas turbine rotor blade vibration amplitudes [1]. Analytical modelling of the casing wall pressures and reconstruction of rotor blade vibration amplitudes from the analysis of these simulated pressure signals have shown potential advantages over current non-contact rotor blade vibration measurement methods. However, the modelling made some fundamental assumptions about the casing wall pressure. One of the assumptions made was that the pressure at the blade tip is not significantly different from that measured across the clearance gap at the casing wall. This fluid-structure hypothesis is investigated in this paper. Unsteady computational fluid dynamic modelling of the flow conditions around the blade surface, combined with the blade structural motion, is performed numerically, and the distributions of the pressure across the rotor blade tip and casing clearance gap are investigated and reported

Climate Change in the High Andes:implications and adaptation strategies for small-scale farmers

Abstract: Global climate change represents a major threat to sustainable farming in the Andes. Farmers have used local ecological knowledge and intricate production systems to cope, adapt and reorganize to meet climate uncertainty and risk, which have always been a fact of life. Those traditional systems are generally highly resilient, but the predicted effects, rates and variability of climate change may push them beyond their range of adaptability. This article examines the extent of actual and potential impacts of climate variability and change on small-scale farmers in the highland Andes of Bolivia, Ecuador and Peru. It describes how climate change impacts agriculture through deglaciation, changes in hydrology, soil and pest and disease populations. The article highlights some promising adaptive strategies currently in use by or possible for producers, rural communities and local institutions to mitigate climate change effects while preserving the livelihoods and environmental and social sustainability of the regio

The Relationship Between Concussion History and Sex on Lower Extremity Biomechanics During a Cutting Task

Athletes with a history of sports related concussion (SRC) have been shown to exhibit lower extremity (LE) mechanics during high impact landing tasks that are conducive to increased injury risk. The underlying cause, and extent of this phenomena is currently unknown. PURPOSE: The purpose of this study was to analyze the relationship between SRC history and sex on LE biomechanics during a land-and-cut task. METHODS: College athletes with a history of SRC and a control group of healthy athletes matched by sport, position, sex, and age were recruited for this study. Both groups were comprised of 9 males and 11 females. Athletes performed an unanticipated land-and-cut task. The task consisted of each athlete standing on a 60 cm box with a visual stimulus positioned three meters away from the athlete. Various colors (green, pink, blue, and red) were presented as the visual stimulus. Athletes were instructed to only respond to a green or red light. When a red or green light was shown, athletes were instructed to step off the box, land on both limbs and perform a 45-degree cutting movement to the left or right, respectively. Two separate point biserial correlations were conducted (one for each sex) correlating group (0 = control, 1 = SRC) with the following dependent variables: vertical ground reaction force (vGRF), peak knee extensor moment (pKEM), peak knee abduction moment (pKAM), peak ankle dorsiflexion angle (pDF), peak knee flexion angle (pKFA), and peak knee abduction angle (pKA). A linear regression equation was obtained for significant correlations. RESULTS: There was a significant negative moderate correlation between group and KF in males (r = -.69, p \u3c .01). There were no other significant correlations between group and LE biomechanical variables in either males or females (p \u3e .05). A linear regression analysis showed SRC history was a significant predictor of KF (KF = 63.71 – 12.43(group); R2 = .473, p = .002) CONCLUSION: Males in the SRC group were associated with lower KF. Specifically, the regression analysis indicated that males with an SRC history had a predicted 12.4 degree decrease in KF during the land-and-cut task. This suggests previously concussed males may be at increased risk for LE injury

Computational Fluid Dynamic Analysis of a Vibrating Turbine Blade

This study presents the numerical fluid-structure interaction (FSI) modelling of a vibrating turbine blade using the commercial software ANSYS-12.1. The study has two major aims: (i) discussion of the current state of the art of modelling FSI in gas turbine engines and (ii) development of a “tuned” one-way FSI model of a vibrating turbine blade to investigate the correlation between the pressure at the turbine casing surface and the vibrating blade motion. Firstly, the feasibility of the complete FSI coupled two-way, three-dimensional modelling of a turbine blade undergoing vibration using current commercial software is discussed. Various modelling simplifications, which reduce the full coupling between the fluid and structural domains, are then presented. The one-way FSI model of the vibrating turbine blade is introduced, which has the computational efficiency of a moving boundary CFD model. This one-way FSI model includes the corrected motion of the vibrating turbine blade under given engine flow conditions. This one-way FSI model is used to interrogate the pressure around a vibrating gas turbine blade. The results obtained show that the pressure distribution at the casing surface does not differ significantly, in its general form, from the pressure at the vibrating rotor blade tip

The endless fountain: essays on classical humanism

(print) xv, 180 p. ; 24 cmPreface ix -- Foreword by Mark Morford xi -- I Charles L. Babcock The Classics and the New Humanism 3 -- II William F. McDonald Classicism, Christianity, and Humanism 28 -- III David F. Heimann Christian Humanism in the Fourth Century : Saint Jerome 58 -- IV Oskar Seidlin Goethe's Iphigenia in Tauris : A Modern Use of a Greek Dramatic Theme 127 -- V Harry C. Rutledge Classical Latin Poetry : An Art for Our Time 136 -- Epilogue by Kenneth M. Abbott 169 -- Notes on the Contributors 173 -- Index 17