21,248 research outputs found
A failsafe analysis using NASTRAN's piecewise linear analysis and a nine node linear crack element
A two-dimensional crack element was implemented into NASTRAN as a user dummy element and used to study failsafe characteristics of the C5A fuselage. The element is formulated from Reitsner's functional requiring that it satisfy compatability with the linear boundary displacement elements in NASTRAN. Its accuracy is demonstrated by analyzing for the stress intensity factors of two simple crack configurations for which there are classic solutions
NASTRAN used in a production environment
A finite element analysis procedure built around the NASTRAN system is assessed. A number of support programs that were either written or modified to interface with NASTRAN and some improvements that were made to NASTRAN itself are noted. Some typical models are analyzed and an actual schedule is followed for constructing and analyzing the models to support a large design program
Peculiar ground: the theology of Isaac Watts
The thesis is designed to demonstrate what was distinctive about Isaac Watts. It begins with a brief account of his life and background. There is no attempt at comprehensive coverage but rather a discussion of significant detail. Then follows a survey of Watts' work - first his poetry, then his prose. Watts' writings on the Atonement are critically analysed, followed by his views on election and predestination. The purpose here is to demonstrate that Watts had a profound commitment to traditional theology, in particular to the doctrine of substitutionary atonement. However, he displays a thoroughly humane and reasonable attitude to the difficulties posed by this doctrine, and by the doctrine of predestination. Watts could fairly be described as a follower of Baxter whom he much admired. His salient characteristics were common sense and devotion to Scripture. Against this background Watts' writings on the Trinity are considered. Here his pursuit of reason and his desire to help others and to reconcile conflicting opinions led him into much more stormy waters. His mature conviction was that God had covenanted with the pre-existent human soul of Christ in order to redeem the world. This mildly heretical doctrine, derived from Origen, served to deflect Watts from out and out Socinianism and Arianism, both of which creeds held a dangerous attraction for him. The possibility is explored that at the end of his life Watts had written tracts which were definitely Unitarian - and which were subsequently destroyed. This would account for the self-torturing anguish of the Solemn Address, Watts' desperate cry to God for help and guidance. Lastly, the 'peculiar' gifts of Isaac Watts are stressed, so that the success of his religious verse can be evaluated. The qualities which he displayed in all his writings combined to produce his 'System of Praise', his enduring legacy to the Christian church. His heresy has been forgotten. But Watts' heresy helps us to understand his hymns, and his hymns help us to understand his heresy
Study of radiation hazards to man on extended near earth missions
Radiation hazards to man on extended near earth mission
NICMOS and VLBA observations of the gravitational lens system B1933+503
NICMOS observations of the complex gravitational lens system B1933+503 reveal
infrared counterparts to two of the inverted spectrum radio images. The
infrared images have arc-like structures. The corresponding radio images are
also detected in a VLBA map made at 1.7 GHz with a resolution of 6 mas. We fail
to detect two of the four inverted radio spectrum components with the VLBA even
though they are clearly visible in a MERLIN map at the same frequency at a
different epoch. The absence of these two components could be due to rapid
variability on a time-scale less than the time delay, or to broadening of the
images during propagation of the radio waves through the ISM of the lensing
galaxy to an extent that they fall below the surface brightness detectability
threshold of the VLBA observations. The failure to detect the same two images
with NICMOS is probably due to extinction in the ISM of the lensing galaxy.Comment: 5 pages, 4 figures, submitted to MNRA
Lattice Model of Sweeping Interface for Drying Process in Water-Granule Mixture
Based on the invasion percolation model, a lattice model for the sweeping
interface dynamics is constructed to describe the pattern forming process by a
sweeping interface upon drying the water-granule mixture. The model is shown to
produce labyrinthine patterns similar to those found in the experiment[Yamazaki
and Mizuguchi, J. Phys. Soc. Jpn. \textbf{69} (2000) 2387]. Upon changing the
initial granular density, resulting patterns undergo the percolation
transition, but estimated critical exponents are different from those of the
conventional percolation. Loopless structure of clusters in the patterns
produced by the sweeping dynamics seems to influence the nature of the
transition.Comment: 6 pages, 7 figure
Synchrotron Polarization at High Galactic Latitude
We present preliminary results from mapping the high-latitude Galactic
polarization with the Effelsberg Telescope at 21 cm. Structures on the
resulting maps are mostly on the scale of several degrees. The results show
detection of polarization over most of the field, at the level of tens of
percent of the synchrotron emission. The evidence of more structure in Stokes Q
and U rather than in suggests the existence of Faraday
rotation.Comment: To be published in the proceedings of "The Cosmic Microwave
Background and its Polarization", New Astronomy Reviews, (eds. S. Hanany and
K.A. Olive
A survey of polarization in the JVAS/CLASS flat-spectrum radio source surveys: I. The data and catalogue production
We have used the very large JVAS/CLASS 8.4-GHz surveys of flat-spectrum radio
sources to obtain a large, uniformly observed and calibrated, sample of radio
source polarizations. These are useful for many investigations of the
properties of radio sources and the interstellar medium. We discuss comparisons
with polarization measurements from this survey and from other large-scale
surveys of polarization in flat-spectrum sources.Comment: Accepted by MNRAS. 8 pages, 5 figures. Full version of Table 2
available at http://www.jb.man.ac.uk/~njj/classqu_po
The kink Casimir energy in a lattice sine-Gordon model
The Casimir energy of quantum fluctuations about the classical kink
configuration is computed numerically for a recently proposed lattice
sine-Gordon model. This energy depends periodically on the kink position and is
found to be approximately sinusoidal.Comment: 10 pages, 4 postscript figure
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