Analysis of a turbine rotor containing a transverse crack at Oak Creek Unit 17

Transient increases in one, two and three per revolution vibration characteristics of a low pressure steam turbine were observed during steam temperature reduction operations. Vibration and fracture mechanics analyses suggested the presence of a transverse shaft crack which was eventually identified by ultrasonic inspection and confirmed by destructive sectioning. Signature analyses of vibration data recorded over a two-year period prior to crack identification are correlated with fatigue crack growth, which occurred intermittently during transient temperature decreases. The apparent increased response of the rotor to vibration is due to asymmetric stiffness changes introduced by the growing transverse crack. The vibration response is predicted to increase with increasing crack depths in excess of 10% of the shaft diameter. Fracture mechanics analyses predict that fatigue crack growth occurred during periods of steam temperature decrease, when high surface tensile stresses are present. These same transient thermal stresses are shown to have retarded and prevented subsequent fatigue crack growth during steady operation

Dynamics of F=2 Spinor Bose-Einstein Condensates

We experimentally investigate and analyze the rich dynamics in F=2 spinor Bose-Einstein condensates of Rb87. An interplay between mean-field driven spin dynamics and hyperfine-changing losses in addition to interactions with the thermal component is observed. In particular we measure conversion rates in the range of 10^-12 cm^3/s for spin changing collisions within the F=2 manifold and spin-dependent loss rates in the range of 10^-13 cm^3/s for hyperfine-changing collisions. From our data we observe a polar behavior in the F=2 ground state of Rb87, while we measure the F=1 ground state to be ferromagnetic. Furthermore we see a magnetization for condensates prepared with non-zero total spin.Comment: 4 pages, 2 figures, RevTe

Second Order Correlation Function of a Phase Fluctuating Bose-Einstein Condensate

The coherence properties of phase fluctuating Bose-Einstein condensates are studied both theoretically and experimentally. We derive a general expression for the N-particle correlation function of a condensed Bose gas in a highly elongated trapping potential. The second order correlation function is analyzed in detail and an interferometric method to directly measure it is discussed and experimentally implemented. Using a Bragg diffraction interferometer, we measure intensity correlations in the interference pattern generated by two spatially displaced copies of a parent condensate. Our experiment demonstrates how to characterize the second order correlation function of a highly elongated condensate and to measure its phase coherence length.Comment: 22 pages, 5 figure

Introduction of a pyramid guiding process for general musculoskeletal physical rehabilitation

Successful instruction of a complicated subject as Physical Rehabilitation demands organization. To understand principles and processes of such a field demands a hierarchy of steps to achieve the intended outcome. This paper is intended to be an introduction to a proposed pyramid scheme of general physical rehabilitation principles. The purpose of the pyramid scheme is to allow for a greater understanding for the student and patient. As the respected Food Guide Pyramid accomplishes, the student will further appreciate and apply supported physical rehabilitation principles and the patient will understand that there is a progressive method to their functional healing process

Perturbation theory for anisotropic dielectric interfaces, and application to sub-pixel smoothing of discretized numerical methods

We derive a correct first-order perturbation theory in electromagnetism for cases where an interface between two anisotropic dielectric materials is slightly shifted. Most previous perturbative methods give incorrect results for this case, even to lowest order, because of the complicated discontinuous boundary conditions on the electric field at such an interface. Our final expression is simply a surface integral, over the material interface, of the continuous field components from the unperturbed structure. The derivation is based on a "localized" coordinate-transformation technique, which avoids both the problem of field discontinuities and the challenge of constructing an explicit coordinate transformation by taking a limit in which a coordinate perturbation is infinitesimally localized around the boundary. Not only is our result potentially useful in evaluating boundary perturbations, e.g. from fabrication imperfections, in highly anisotropic media such as many metamaterials, but it also has a direct application in numerical electromagnetism. In particular, we show how it leads to a sub-pixel smoothing scheme to ameliorate staircasing effects in discretized simulations of anisotropic media, in such a way as to greatly reduce the numerical errors compared to other proposed smoothing schemes.Comment: 10 page

Single-cycle viral gene expression, rather than progressive replication and oncolysis, is required for VSV therapy of B16 melanoma

A fully intact immune system would be expected to hinder the efficacy of oncolytic virotherapy by inhibiting viral replication. Simultaneously, however, it may also enhance antitumor therapy through initiation of proinflammatory, antiviral cytokine responses at the tumor site. The aim of this study was to investigate the role of a fully intact immune system on the antitumor efficacy of an oncolytic virus. In this respect, injection of oncolytic vesicular stomatitis virus (VSV) into subcutaneous B16ova melanomas in C57Bl/6 mice leads to tumor regression, but it is not associated with viral replicative burst in the tumor. In contrast, intratumoral delivery of VSV induces an acute proinflammatory reaction, which quickly resolves concomitantly with virus clearance. Consistent with the hypothesis that therapy may not be dependent on the ability of VSV to undergo progressive rounds of replication, a single-cycle VSV is equally effective as a fully replication-competent VSV, whereas inactivated viruses do not generate therapy. Even though therapy is dependent on host CD8+ and natural killer cells, these effects are not associated with interferon-γ-dependent responses against either the virus or tumor. There is, however, a strong correlation between viral gene expression, induction of proinflammatory reaction in the tumor and in vivo therapy. Overall, our results suggest that acute innate antiviral immune response, which rapidly clears VSV from B16ova tumors, is associated with the therapy observed in this model. Therefore, the antiviral immune response to an oncolytic virus mediates an intricate balance between safety, restriction of oncolysis and, potentially, significant immune-mediated antitumor therapy