13,438 research outputs found

    Advanced high temperature heat flux sensors

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    To fully characterize advanced high temperature heat flux sensors, calibration and testing is required at full engine temperature. This required the development of unique high temperature heat flux test facilities. These facilities were developed, are in place, and are being used for advanced heat flux sensor development

    The Philippines

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    Fast atom diffraction inside a molecular beam epitaxy chamber, a rich combination

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    Two aspects of the contribution of grazing incidence fast atom diffraction (GIFAD) to molecular beam epitaxy (MBE) are reviewed here: the ability of GIFAD to provide \emph{in-situ} a precise description of the atomic-scale surface topology, and its ability to follow larger-scale changes in surface roughness during layer-by-layer growth. Recent experimental and theoretical results obtained for the He atom beam incident along the highly corrugated [11ˉ0][ 1\bar{1}0 ] direction of the β2\beta_{2}(2×\times4) reconstructed GaAs(001) surface are summarized and complemented by the measurements and calculations for the beam incidence along the weakly corrugated [010] direction where a periodicity twice smaller as expected is observed. The combination of the experiment, quantum scattering matrix calculations, and semiclassical analysis allows in this case to reveal structural characteristics of the surface. For the in situ measurements of GIFAD during molecular beam epitaxy of GaAs on GaAs surface we analyse the change in elastic and inelastic contributions in the scattered beam, and the variation of the diffraction pattern in polar angle scattering. This analysis outlines the robustness, the simplicity and the richness of the GIFAD as a technique to monitor the layer-by-layer epitaxial growth

    The Cell\u27s Antenna and Bending with the Flow

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    Polycystic kidney disease (PKD) is the most common life-threatening genetic disease worldwide – affecting about 12.5 million people. Patients with the condition have multiple fluid-filled cysts in their kidneys that lead to a massive enlargement of the organ and gradual worsening of its function, as well as complete failure in many cases. The lack of available treatment means patients may eventually require regular dialysis or a kidney transplant

    About the maximal rank of 3-tensors over the real and the complex number field

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    High dimensional array data, tensor data, is becoming important in recent days. Then maximal rank of tensors is important in theory and applications. In this paper we consider the maximal rank of 3 tensors. It can be attacked from various viewpoints, however, we trace the method of Atkinson-Stephens(1979) and Atkinson-Lloyd(1980). They treated the problem in the complex field, and we will present various bounds over the real field by proving several lemmas and propositions, which is real counterparts of their results.Comment: 13 pages, no figure v2: correction and improvemen

    Positive solutions to indefinite Neumann problems when the weight has positive average

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    We deal with positive solutions for the Neumann boundary value problem associated with the scalar second order ODE u"+q(t)g(u)=0,t∈[0,T], u" + q(t)g(u) = 0, \quad t \in [0, T], where g:[0,+∞[ →Rg: [0, +\infty[\, \to \mathbb{R} is positive on  ]0,+∞[ \,]0, +\infty[\, and q(t)q(t) is an indefinite weight. Complementary to previous investigations in the case ∫0Tq(t)<0\int_0^T q(t) < 0, we provide existence results for a suitable class of weights having (small) positive mean, when g′(x)<0g'(x) < 0 at infinity. Our proof relies on a shooting argument for a suitable equivalent planar system of the type x′=y,y′=h(x)y2+q(t), x' = y, \qquad y' = h(x)y^2 + q(t), with h(x)h(x) a continuous function defined on the whole real line.Comment: 17 pages, 3 figure

    New Deal Agricultural Appropriations: A Political Influence

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    This study investigates the allocation of New Deal appropriations to agricultural interests in Alabama's sixty-seven counties during the Great Depression. Conventional wisdom indicates that Roosevelt, through the New Deal, brought assistance to those in need. However, recent literature has identified a political motivation to the pattern of spending that emerged during the economic downturn. The authors develop and estimate a model with data which has only recently become available. The results show that while communities with the highest farm income received larger appropriations as expected, counties that experienced a collapse in farm income during the Great Depression received no special consideration from those officials responsible for distributing New Deal dollars across the state. These results indicate that self-interest was an important motivator in allocating agricultural appropriations in the state of Alabama during the Great Depression.Depression

    Neural Network-Based Equations for Predicting PGA and PGV in Texas, Oklahoma, and Kansas

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    Parts of Texas, Oklahoma, and Kansas have experienced increased rates of seismicity in recent years, providing new datasets of earthquake recordings to develop ground motion prediction models for this particular region of the Central and Eastern North America (CENA). This paper outlines a framework for using Artificial Neural Networks (ANNs) to develop attenuation models from the ground motion recordings in this region. While attenuation models exist for the CENA, concerns over the increased rate of seismicity in this region necessitate investigation of ground motions prediction models particular to these states. To do so, an ANN-based framework is proposed to predict peak ground acceleration (PGA) and peak ground velocity (PGV) given magnitude, earthquake source-to-site distance, and shear wave velocity. In this framework, approximately 4,500 ground motions with magnitude greater than 3.0 recorded in these three states (Texas, Oklahoma, and Kansas) since 2005 are considered. Results from this study suggest that existing ground motion prediction models developed for CENA do not accurately predict the ground motion intensity measures for earthquakes in this region, especially for those with low source-to-site distances or on very soft soil conditions. The proposed ANN models provide much more accurate prediction of the ground motion intensity measures at all distances and magnitudes. The proposed ANN models are also converted to relatively simple mathematical equations so that engineers can easily use them to predict the ground motion intensity measures for future events. Finally, through a sensitivity analysis, the contributions of the predictive parameters to the prediction of the considered intensity measures are investigated.Comment: 5th Geotechnical Earthquake Engineering and Soil Dynamics Conference, Austin, TX, USA, June 10-13. (2018

    Morphological characteristics of the sinus node on postmortem tissue

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    The sinus node is an intensively researched structure in terms of anatomical, histological, electrophysiological, molecular and genetic approach. For postmortem diagnosis it is still difficult to investigate due to a still reduced accessibility. In this study we tried and succeed to apply molecular biology techniques on postmortem tissues in order to widen the range of postmortem forensic investigation and provide information related to the diagnostic of cardiac arrhythmia. We described the stages of this investigation, with dissection, preservation and analysis that included classical histology, immunohistochemistry, confocal microscope, microdissection, RIN testing, mRNA expression obtaining a precise morphofunctional location of the sinus node

    Local transport in a disorder-stabilized correlated insulating phase

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    We report the experimental realization of a correlated insulating phase in 2D GaAs/AlGaAs heterostructures at low electron densities in a limited window of background disorder. This has been achieved at mesoscopic length scales, where the insulating phase is characterized by a universal hopping transport mechanism. Transport in this regime is determined only by the average electron separation, independent of the topology of background disorder. We have discussed this observation in terms of a pinned electron solid ground state, stabilized by mutual interplay of disorder and Coulomb interaction.Comment: 4+delta pages, 4 figures, To appear in the Physical Review B (Rapid Comm
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