Photosensors used to maintain welding electrode-to-joint alignment

Photosensors maintain electrode-to-joint alignment in automatic precision arc welding. They detect the presence and relative position of a joint to be welded and actuate a servomechanism to guide the welding head accordingly thus permitting alignment for more than straight line or true circle joints

Bowen Measure From Heteroclinic Points

We present a new construction of the entropy-maximizing, invariant probability measure on a Smale space (the Bowen measure). Our construction is based on points that are unstably equivalent to one given point, and stably equivalent to another: heteroclinic points. The spirit of the construction is similar to Bowen's construction from periodic points, though the techniques are very different. We also prove results about the growth rate of certain sets of heteroclinic points, and about the stable and unstable components of the Bowen measure. The approach we take is to prove results through direct computation for the case of a Shift of Finite type, and then use resolving factor maps to extend the results to more general Smale spaces

Reinsurance in State Health Reform

Based on the experiences of three states, formal modeling, quantitative estimates, and qualitative assessments, explores the impact of and issues involved in publicly funding reinsurance for insurers as a way to expand or maintain private coverage

A Comparison of Absorption and Emission Line Abundances in the Nearby Damped Lyman-alpha Galaxy SBS 1543+593

We have used the Space Telescope Imaging Spectrograph (STIS) aboard HST to measure a sulfur abundance of [S/H] = -0.41 +/-0.06 in the interstellar medium (ISM) of the nearby damped Lyman-alpha (DLA) absorbing galaxy SBS 1543+593. A direct comparison between this QSO absorption line abundance on the one hand, and abundances measured from HII region emission line diagnostics on the other, yield the same result: the abundance of sulfur in the neutral ISM is in good agreement with that of oxygen measured in an HII region 3 kpc away. Our result contrasts with those of other recent studies which have claimed order-of-magnitude differences between HI (absorption) and HII (emission) region abundances. We also derive a nickel abundance of [Ni/H] < -0.81, some three times less than that of sulfur, and suggest that the depletion is due to dust, although we cannot rule out an over-abundance of alpha-elements as the cause of the lower metallicity. It is possible that our measure of [S/H] is over-estimated if some SII arises in ionized gas; adopting a plausible star formation rate for the galaxy along the line of sight, and a measurement of the CII* 1335.7 absorption line detected from SBS 1543+593, we determine that the metallicity is unlikely to be smaller than we derive by more than 0.25 dex. We estimate that the cooling rate of the cool neutral medium is log [l_c (ergs s^{-1} H atom^{-1})] = -27.0, the same value as that seen in the high redshift DLA population.Comment: 31 pages; accepted for publication in the Ap

The Urban Institute's Microsimulation Model for Reinsurance: Model Construction and State-Specific Application

Describes the Urban Institute's model for simulating the effects of using state-funded reinsurance to subsidize primary insurance premiums. Details the process of building state-specific baseline databases and modeling reinsurance policy options

Report of the Rock Lobster Industry Advisory Committee meeting of 27 January 1987 - Report by the Chairman Mr. B.K. Bowen.

The Rock Lobster Industry Advisory Committee met in Perth on Tuesday 17 January 1987. Committee discussed the following: Policy on 5% pot loss on replacement of vessels less than six years old. Study of industry funded compensation mechanism for fishing capacity reductions. 20 Fathom rule. Future maintenance of the zone E boundary. The recreational Rock Lobster Fishery. Rock Lobster pot distribution. Options for a 10 per cent reduction in fishing effort. 1987 coastal tour. Augusta-Windy Harbour Rock Lobster Working Group. Report on the 1986/87 season

The materials processing research base of the Materials Processing Center

The goals and activities of the center are discussed. The center activities encompass all engineering materials including metals, ceramics, polymers, electronic materials, composites, superconductors, and thin films. Processes include crystallization, solidification, nucleation, and polymer synthesis

General Relativistic Gas Dynamics in the Central Cavity of Binary Black Holes

Supermassive binary black holes (SMBBHs) represent an excellent candidate for future combined gravitational wave and electromagnetic astrophysics, commonly referred to as multimessenger astrophysics. While much is known about the gravitational wave signal of merging BBHs, little is known about the electromagnetic emission. Modeling the electromagnetic emission coincident with gravitational waves requires simulations of SMBBHs coupled to their astrophysical environment, particularly during the late stages of inspiral and merger. These simulations necessitate a broad range of physics including general relativity, magnetohydrodynamics, and radiation physics. In this Dissertation we present simulations of SMBBHs coupled to their astrophysical environment. We explore, for the first time, the gas dynamics in a relativistic binary black hole (BBH) system in which an accretion disk (a mini-disk ) orbits each black hole. In addition to studying the structure and dynamics of the mini-disks, we present spectra from ray-tracing calculations of SMBBH accretion including mini-disks. Due to the immense computational burden of these simulations (millions of CPU hours per binary orbit), we restrict our study to equal-mass, non-spinning SMBBHs. Relativistic effects alter the dynamics of gas in this environment in several ways. Because the gravitational potential between the two black holes becomes shallower than in the Newtonian regime, the mini-disks stretch toward the L1 point and the amount of gas passing back and forth between the mini-disks increases sharply with decreasing binary separation. This \enquote{sloshing} is quasi-periodically modulated at 2 and 2.75 times the binary orbital frequency, corresponding to timescales of hours to days for SMBBHs. In addition, relativistic effects add an azimuthal m = 1 component to the tidally driven spiral waves in the disks that are purely m = 2 in Newtonian gravity; this component becomes dominant when the separation islatter. This modulation in the accretion stream flux has a quasi-periodic nature of 0.74 times the binary orbital frequency. Both the sloshing and the spiral waves have the potential to create distinctive radiation features that may uniquely mark SMBBHs in the relativistic regime. Finally, we observe a broadened thermal spectrum due to the combined photospheres of the mini-disks and circumbinary disks in the range of approximately 1 - 1000eV, and an inverse Compton spectrum at tens to hundreds of keV dominated by the mini-disks

Collisions of boosted black holes: perturbation theory prediction of gravitational radiation

We consider general relativistic Cauchy data representing two nonspinning, equal-mass black holes boosted toward each other. When the black holes are close enough to each other and their momentum is sufficiently high, an encompassing apparent horizon is present so the system can be viewed as a single, perturbed black hole. We employ gauge-invariant perturbation theory, and integrate the Zerilli equation to analyze these time-asymmetric data sets and compute gravitational wave forms and emitted energies. When coupled with a simple Newtonian analysis of the infall trajectory, we find striking agreement between the perturbation calculation of emitted energies and the results of fully general relativistic numerical simulations of time-symmetric initial data.Comment: 5 pages (RevTex 3.0 with 3 uuencoded figures), CRSR-107

Teleportation of continuous variable polarisation states

This paper discusses methods for the optical teleportation of continuous variable polarisation states. We show that using two pairs of entangled beams, generated using four squeezed beams, perfect teleportation of optical polarisation states can be performed. Restricting ourselves to 3 squeezed beams, we demonstrate that polarisation state teleportation can still exceed the classical limit. The 3-squeezer schemes involve either the use of quantum non-demolition measurement or biased entanglement generated from a single squeezed beam. We analyse the efficacies of these schemes in terms of fidelity, signal transfer coefficients and quantum correlations