14,018 research outputs found
What role does the right side of the heart play in circulation?
Right ventricular failure (RVF) is an underestimated problem in intensive care. This review explores the physiology and pathophysiology of right ventricular function and the pulmonary circulation. When RVF is secondary to an acute increase in afterload, the picture is one of acute cor pulmonale, as occurs in the context of acute respiratory distress syndrome, pulmonary embolism and sepsis. RVF can also be caused by right myocardial dysfunction. Pulmonary arterial catheterization and echocardiography are discussed in terms of their roles in diagnosis and treatment. Treatments include options to reduce right ventricular afterload, specific pulmonary vasodilators and inotropes
Optically exciting a magnetic memory - A feasibility study
Rare earth iron garnets were used in experiments to determine the feasibility of optically pumping a magnetic material to effect the switching process. It was found that rare earth garnets are limited by an absorption edge, only terbium and dysprosium offer a possibility of pumping at energies below the conduction band edge
Methods and costs associated with outfitting light aircraft for remote sensing applications
This document was designed to provide the potential user of a light aircraft remote sensor platform/data gathering system with general information on aircraft definition, implementation complexity, costs, scheduling and operational factors involved in this type of activity. Most of the subject material was developed from actual situations and problem areas encountered during the build-up cycle and early phases of flight operations
Strength Tests on Paper Cylinder in Compression, Bending and Shear
Static tests on paper cylinders were conducted at the Langley Memorial Aeronautical Laboratory at Langley Field, Virginia, to obtain qualitative information in connection with a study of the strength of stressed-skin fuselages. The effects of radius-thickness ratio and bulkhead spacing were investigated with the cylinders in compression, bending, combined bending and shear, and torsion
Applications of the magneto-optical filter to stellar pulsation measurements
A proposed method of employing the Cacciani magneto-optical filter (MOF) for stellar seismology studies is described. The method relies on the fact that the separation of the filter bandpasses in the MOF can be changed by varying the level of input power to the filter cells. With the use of a simple servosystem the bandpass of a MOF can be tuned to compensate for the changes in the radial velocity of a star introduced by the orbital motion of the Earth. Such a tuned filter can then be used to record intensity fluctuations through the MOF bandpass over an extended period of time for each given star. Also, the use of a two cell version of the MOF makes it possible to alternately chop between the bandpass located in the stellar line wing and a second bandpass located in the stellar continuum. Rapid interchange between the two channels makes it possible for atmospheric-introduced noise to be removed from the time series
A Study of Flow Separation in Transonic Flow Using Inviscid and Viscous Computational Fluid Dynamics (CFD) Schemes
A comparison of flow separation in transonic flows is made using various computational schemes which solve the Euler and the Navier-Stokes equations of fluid mechanics. The flows examined are computed using several simple two-dimensional configurations including a backward facing step and a bump in a channel. Comparison of the results obtained using shock fitting and flux vector splitting methods are presented and the results obtained using the Euler codes are compared to results on the same configurations using a code which solves the Navier-Stokes equations
Nonlinearity and pixel shifting effects in HXRG infrared detectors
We study the nonlinearity (NL) in the conversion from charge to voltage in
infrared detectors (HXRG) for use in precision astronomy. We present laboratory
measurements of the NL function of a H2RG detector and discuss the accuracy to
which it would need to be calibrated in future space missions to perform
cosmological measurements through the weak gravitational lensing technique. In
addition, we present an analysis of archival data from the infrared H1RG
detector of the Wide Field Camera 3 in the Hubble Space Telescope that provides
evidence consistent with the existence of a sensor effect analogous to the
brighter-fatter effect found in Charge-Coupled Devices. We propose a model in
which this effect could be understood as shifts in the effective pixel
boundaries, and discuss prospects of laboratory measurements to fully
characterize this effect.Comment: Accepted for publication in the Journal of Instrumentation (JINST).
Part of "Precision Astronomy with Fully Depleted CCDs" (Dec 1-2, 2016),
Brookhaven National Laboratory, Upton, NY, US
Assifidity Days and Other Poems
I now believe at this end of this writing that there are three stages through which the poet and his poetry move in the accomplishment of any poem; stages in relation to this poet only, in development of these poems. Since we can agree that poetry is a highly personal statement (a dangerous thing in itself today), it is with poetry as personal statement that I would like to begin
- …