512 research outputs found
Experimental flow coefficients of a full-coverage film-cooled-vane chamber
Ambient- and elevated-temperature flow tests were performed on a four-times-actual-size model of an impingement- and film-cooled segment of a core engine turbine vane. Tests were conducted with the impingement and film cooling plates combined to form a chamber and also with each of the individual separated plates. For the combined tests, the proximity of the film cooling plate affected the flow of coolant through the impingement plate, but not conversely. Impingement flow is presented in terms of a discharge coefficient, and the film cooling flow discharging into still air with no main stream gas flow is presented in terms of a total pressure-loss coefficient. The effects of main stream gas flow on discharge from the film cooling holes are evaluated as a function of coolant to main-stream gas momentum flux ratio. A smoothing technique is developed that identifies and helps reduce flow measurement data scatter
Exploring affective design for physical controls
Physical controls such as knobs, sliders, and buttons are experiencing a revival as many computing systems progress from personal computing architectures towards ubiquitous computing architectures. We demonstrate a process for measuring and comparing visceral emotional responses of a physical control to performance results of a target acquisition task. In our user study, participants experienced mechanical and rendered friction, inertia, and detent dynamics as they turned a haptic knob towards graphical targets of two different widths and amplitudes. Together, this process and user study provide novel affect- and performance-based design guidance to developers of physical controls for emerging ubiquitous computing environments. Our work bridges extensive human factors work in mechanical systems that peaked in the 1960’s, to contemporary trends, with a goal of integrating mechatronic controls into emerging ubiquitous computing systems. Author Keywords Haptic display, physical control, design process, affect
Elastic and Raman scattering of 9.0 and 11.4 MeV photons from Au, Dy and In
Monoenergetic photons between 8.8 and 11.4 MeV were scattered elastically and
in elastically (Raman) from natural targets of Au, Dy and In.15 new cross
sections were measured. Evidence is presented for a slight deformation in the
197Au nucleus, generally believed to be spherical. It is predicted, on the
basis of these measurements, that the Giant Dipole Resonance of Dy is very
similar to that of 160Gd. A narrow isolated resonance at 9.0 MeV is observed in
In.Comment: 31 pages, 11 figure
From Majorana theory of atomic autoionization to Feshbach resonances in high temperature superconductors
The Ettore Majorana paper - Theory of incomplete P triplets- published in
1931, focuses on the role of selection rules for the non-radiative decay of two
electron excitations in atomic spectra, involving the configuration interaction
between discrete and continuum channels. This work is a key step for
understanding the 1935 work of Ugo Fano on the asymmetric lineshape of two
electron excitations and the 1958 Herman Feshbach paper on the shape resonances
in nuclear scattering arising from configuration interaction between many
different scattering channels. The Feshbach resonances are today of high
scientific interest in many different fields and in particular for ultracold
gases and high Tc superconductivity.Comment: 13 pages, 7 figures. Journal of Superconductivity and Novel Magnetism
to be publishe
Scaling Laws and Transient Times in 3He Induced Nuclear Fission
Fission excitation functions of compound nuclei in a mass region where shell
effects are expected to be very strong are shown to scale exactly according to
the transition state prediction once these shell effects are accounted for. The
fact that no deviations from the transition state method have been observed
within the experimentally investigated excitation energy regime allows one to
assign an upper limit for the transient time of 10 zs.Comment: 7 pages, TeX type, psfig, submitted to Phys. Rev. C, also available
at http://csa5.lbl.gov/moretto/ps/he3_paper.p
Fission of multielectron bubbles in liquid helium
The stability of multielectron bubbles (MEBs) in liquid helium is
investigated using the liquid-drop model for fissioning nuclei. Whereas a
critical positive pressure can make the bubble unstable against fissioning, a
small negative pressure suffices to introduce a restoring force preventing any
small deformation of the bubble to grow. We also find that there exists an
energy barrier making MEBs metastable against fissioning at zero pressure. The
results obtained here overcome the difficulties associated with the
Rayleigh-Plesset equation previously used to study bubble stability, and shed
new light on the limits of achievable bubble geometries in recently proposed
experiments devised to stabilize MEBs.Comment: 11 pages and 5 figures, accepted in Phys. Rev.
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Expression Analysis of Barrett's Esophagus-Associated High-Grade Dysplasia in Laser Capture Microdissected Archival Tissue
Purpose: Identifying genes differentially expressed in nondysplastic BE (NDBE) from those expressed in high-grade dysplasia (HGD) should be of value in improving our understanding of this transition and may yield new diagnostic and/or prognostic markers. The aim of this study was to determine the differential transcriptome of HGD compared with NDBE through gene microarray analysis of epithelial cells microdissected from archival tissue specimens. Experimental Design: Laser capture microdissection was used to isolate epithelial cells from adjacent inflammatory and stromal cells. Epithelial mRNA was extracted from areas of NDBE and HGD in matched biopsies from 11 patients. mRNA was reverse transcribed and applied on Affymetrix cDNA microarray chips customized for formalin-exposed tissue. For a subset of these genes, differential gene expression was confirmed by real-time PCR and immunohistochemistry. Results: There were 131 genes overexpressed by at least 2.5-fold in HGD versus NDBE and 16 genes that were underexpressed by at least 2.5-fold. Among the overexpressed genes are several previously shown to be increased in the neoplastic progression of BE, as well as novel genes such as lipocalin-2, S100A9, matrix metallopeptidase 12, secernin 1, and topoisomerase IIα. Genes decreased in dysplastic epithelium include MUC5AC, trefoil factor 1 (TFF1), meprin A, and CD13. Real-time PCR validated the changes in expression in 24 of 28 selected genes. Immunohistochemistry confirmed increased protein expression for topoisomerase IIα, S100A9, and lipocalin-2 and decreased expression of TFF1 across the spectrum of BE-associated dysplasia from NDBE through adenocarcinoma. Conclusions: This is the first study to identify epithelial genes differentially expressed in HGD versus NDBE in matched patient samples. The genes identified include several previously implicated in the pathogenesis of BE-associated dysplasia and new candidates for further investigation
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