91,493 research outputs found
Vertical boring mill capacity is increased
Commercially available vertical boring mill with a nominal capacity to 27 feet in diameter of workpiece has been modified in-shop to handle work up to 36 feet in diameter. Capacity was increased by adding extension saddles to the mill support columns on each side
Vibration dampener for Niles vertical boring mill ram
Controlled hydraulic cylinder, which serves as a vibration dampener, is used as a ram support unit. Constant pressure is exerted, minimizing the cutting tool vibration
Exact solution of lossy asymmetrical coupled dielectric slab waveguides
This paper gives an exact characteristic equation for asymmetrical coupled dielectric slab waveguides with losses in both the guiding and surrounding regions. For the lossless case the solution of a single transcendental equation is all that is required for the evaluation of the propagation constant
Electrochemical detection device
A standard pH reference electrode and a platinum cathodic electrode are positioned in a container with suitable nutrient medium for microbial growth plus the sample to be tested. The two electrodes are connected to electronic circuitry including an up/down counter whicn counts up for the first 80 minutes after a test has initiated. Then the potential between the two electrodes is tracked by the electronic circuitry and after there is a change of 10 mv a signal is sent to the up/down counter to cause it to reverse its count. When there is a additional 20 mv change in the potential between the two electrodes another signal is sent to the up/down counter, signalling it to stop. The resulting count on the counter is equal to the length of time for the inoculum to begin the production of measurable amounts of H2 after inoculation
Attenuation of aircraft noise by wood-sided and brick-veneered frame houses
Jet aircraft noise attenuation characteristics of wood-sided and brick-veneered frame house
Boundary behavior of analytic functions of two variables via generalized models
We describe a generalization of the notion of a Hilbert space model of a
function in the Schur class of the bidisc. This generalization is well adapted
to the investigation of boundary behavior at a mild singularity of the function
on the 2-torus. We prove the existence of a generalized model with certain
properties corresponding to such a singularity and use this result to solve two
function-theoretic problems. The first of these is to characterise the
directional derivatives of a function in the Schur class at a singular point on
the torus for which the Carath\'eodory condition holds. The second is to obtain
a representation theorem for functions in the two-variable Pick class analogous
to the refined Nevanlinna representation of functions in the one-variable Pick
class.Comment: 30 page
CDTI: Crew Function Assessment
Man machine interaction often requires the operator to perform a sterotyped scan of instruments to monitor and/or control a system. Situations in which this type of behavior exists, such as instrument flight, scan pattern has been shown to be altered by imposition of simultaneous verbal tasks. The relationship between pilot visual scan of instruments and mental workload was described. A verbal loading task of varying difficulty caused pilots to stare at the primary instrument as the difficulty increased and to shed looks at instruments of less importance. The verbal loading task affected rank ordering of scanning sequences. The behavior of pilots with widely varying skill levels suggested that these effects occur most strongly at lower skill levels and are less apparent at high skill levels. Graphical interpretation of the hypothetical relationship between skill, workload, and performance is introduced and modeling results are presented to support this interpretation
Iron line profiles including emission from within the innermost stable orbit of a black hole accretion disc
Reynolds & Begelman (1997) have recently proposed a model in which the broad
and extremely redshifted iron line seen during a deep minimum of the light
curve of the Seyfert 1 galaxy MCG-6-30-15 originates from matter spiralling
into a Schwarzschild black hole, contrary to previous claims that the black
hole may be spinning rapidly (Iwasawa et al 1996; Dabrowski et al 1997). Here
we calculate in detail the X-ray spectrum produced by their model using the
full reflected continuum emission, including absorption features. This
calculation takes into account the doppler and relativistic effects. For the
range of parameters we consider, we find that the spectrum should show a large
photoelectric absorption edge of iron, which is not seen in the data. The
absorption edge is a consequence of the line emitting matter within the
innermost stable orbit being highly ionized, and is largely independent of the
parameters chosen for their model. If we restrict our attention to the 3-10 keV
band we may effectively remove this absorption edge by fitting a steeper power
law, but this results in a significant underprediction of the 0.4-0.5 keV flux.
We conclude that the data on MCG-6-30-15 are more consistent with the Kerr than
the Schwarzschild model.Comment: 5 pages with 5 postscript figures. Accepted for publication in MNRA
Characterization of a thermoplastic polyimidesulfone
The detailed characterization of an experimental thermoplastic polyimidesulfone adhesive based on 3,3 prime-diaminodiphenylsulfone and 3,3 prime,4,4 prime-benzophenone tetracarboxylic dianhydride was studied. Model compounds were also examined. Thermal cyclization of the amide-acid to the imide was studied by a variety of techniques including DSC, TGA, MS, in situ diffuse reflectance-FTIR, and flow mearsurement. Characterizations were continued during the processing of adhesive tapes and the fabrication, bonding, and testing of lap shear specimens. Results provide fundamental insights into the role of cure chemistry, and the effects of residual solvent and volatile produces on processing and performance. These insights and the resulting chemical models should lead to more efficient processing cycles for these and other related thermoplastic adhesive systems
Nevanlinna representations in several variables
We generalize two integral representation formulae of Nevanlinna to functions
of several variables. We show that for a large class of analytic functions that
have non-negative imaginary part on the upper polyhalfplane there are
representation formulae in terms of densely defined self-adjoint operators on a
Hilbert space. We introduce three types of structured resolvent of a
self-adjoint operator and identify four different types of representation in
terms of these resolvents. We relate the types of representation that a
function admits to its growth at infinity.Comment: 37 pages. In this version we have added some references and expanded
the introductio
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