Transfer Matrix Analysis of the Unidirectional Grating-Assisted Codirectional Coupler

The unidirectional grating-assisted codirectional coupler (U-GACC) has recently been proposed. This unique structure permits irreversible coupling between orthogonal waveguide eigenmodes by means of simultaneous modulation of both the real and imaginary parts of the refractive index in the coupling region. Analysis of the U-GACC has until now relied on coupled mode theory, which can be restrictive in its application as a design tool. We analyze the U-GACC by the transfer matrix method, which demonstrates in a simple fashion why the device operates in a unidirectional manner. In addition, we show that for all practical designs, there is a limit to the minimum cross talk between outputs, a phenomenon that has not been previously identified

Mediation In International Commercial Arbitration: Some Practical Aspects

In international commercial arbitration, some disputes cry out for informal resolution by the parties themselves. In assessing their response, parties, arbitrators and arbital institutions must have in mind fundamental, practical and ethical considerations. This paper addresses some of the practical and provocative issues raised in these circumstances

Unemployment and illegal drug use: Concordant evidence from a prospective study and national trends

Data from a previous study of 1036 young people in the Lothian region that indicated an association between unemployment and illegal drug use were examined in more depth to investigate the inter-relation between duration of unemployment and the use of illegal drugs, alcohol, and tobacco. After factors such as social class background and educational qualifications had been taken into account a weak but significant association was found between duration of unemployment and illegal drug use. No such association was found for alcohol or tobacco. Similar results were obtained from an analysis of national statistics related to unemployment and illegal drug use. Both sets of data thus indicate that illegal drug use is moderately associated with unemployment. © 1986, British Medical Journal Publishing Group. All rights reserved

System characterization of a magnetically suspended flywheel

The purpose of flywheel energy storage is to provide a means to save energy during times when the satellite is in sunlight, and then return the energy during the time when the satellite is in darkness. Typically, an energy storage device operates cyclically, where for satellites in Low Earth Orbit (LEO) the typical period is 60 minutes of sunlight followed by 30 minutes of darkness. If a lifetime of 17 years is required the energy storage system must be capable of sustaining approximately 100,000 cycles. The recent developments at the University of Maryland and how these progressions apply to a 500 Watt-hour magnetically suspended flywheel stack energy storage system are covered. The work includes hardware testing results from a stack flywheel energy storage system, improvements in the area of non-contacting displacement transducers, and performance enhancements of magnetic bearings. The experimental results show that a stack flywheel energy storage system is a feasible technology

Field Test of a Remote Multi-Path CLaDS Methane Sensor

Existing technologies for quantifying methane emissions are often limited to single point sensors, making large area environmental observations challenging. We demonstrate the operation of a remote, multi-path system using Chirped Laser Dispersion Spectroscopy (CLaDS) for quantification of atmospheric methane concentrations over extended areas, a technology that shows potential for monitoring emissions from wetlands