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An expansion at the Wabash Valley Correctional Institution (WVCI) required development over abandoned coal mine workings. An extensive geotechnical investigation determined subsidence could occur at the surface. Building the Phase II structures was nevertheless determined economically feasible at least in part due to sharing of facilities and resources with the already existing Phase I Institute. In order to limit the possible subsidence damage to the Phase II structures, raft foundations, mine backfilling, and other structural enhancements were considered. Backfilling of this entirely flooded mine at 300 feet beneath the surface in critical areas was determined to be the most cost-effective for many of the buildings. Each mine area was first contained by strategically placing containment grout in certain entries and cross cuts. Once the barriers were sufficiently constructed, the remaining volume was filled with a flowable infill grout. In the highly rubblized areas, set retarder/plasticizer (calcium lignosulfonate) was used to increase penetration. Once the grouting operation began, the grout movement was monitored in adjacent holes using an electric resistivity probe. After grouting operation was finished, core samples were obtained from verification holes drilled in the backfilled mine areas.

A single pulsed laser beam containing multiple wavelengths (wavelength multiplexing) is employed to activate two semiconductor antennas in series. The dielectric nature of the semiconductors permits serial cascading of the antenna elements. Recently observed nonlinear characteristics of the radiated field as a function of the free carrier accelerating (bias) voltage are used to minimize the small interactions between elements. We demonstrate that the temporal electromagnetic radiation distribution of two serial antennas is sensitive to the three-dimensional pattern of the optical excitation source. One can, in turn, vary this distribution continuously by optical means to reconfigure the array.

The discharge summary communicates information about a patient's stay in hospital and follows the hand written summary that accompanies the patient on discharge. Previous studies have indicated dissatis-faction among general practitioners with the quality of discharge summaries.1 2 Most are done by senior house officers, and this survey assesses their experience in preparing them. A medical senior house officer from each of 100 acute hospitals in England replied to a telephoned questionnaire about teaching they had received on preparing discharge summaries and arrangements for doing summaries in their hospital. Ninety two of the doctors prepared summaries in their present post. On six firms the house physician was responsible, while a consultant and registrar were responsible in the other two. Six senior house …

Many new electronic systems, including spread spectrum links, require frequency synthesizers capable of providing accurate signals of high spectral purity, and must be able to change frequencies in fractions of a microsecond. Three such synthesizers based on comb generators, SAW filterbanks, and fast switches are reviewed. Each of these synthesizers can provide an output at approximately 1.3 GHz from one of over 200 frequencies of integral megahertz value.

The temperature and frequency dependence of the attenuation of 0.5–5‐GHz acoustic surface waves on LiNbO3 has been measured. For propagation in vacuum a frequency‐squared dependence of the total attenuation is obtained with a value at 1 GHz of 0.9 dB/μsec. Temperature‐dependence measurements using a novel three‐transducer technique show the dominant loss (0.7 dB/μsec at 1 GHz) mechanism to be the interaction with thermally excited elastic waves. Propagation in air results in an additional loss linearly proportional to frequency with a value of 0.2 dB/μsec at 1 GHz. The effects of beam steering and diffraction losses are also investigated both theoretically and experimentally. Both misalignment of transducers with respect to pure mode propagation axes and misalignment of the propagation‐plane perpendicular can add significantly to delay line insertion loss. This beam steering loss on Y‐cut Z‐propagating LiNbO3 is considerably higher than on the 41.5° rotated‐cut X‐propagating orientation. The loss mechanis...

Summary Two patients with insulin-dependent diabetes mellitus (Type I), developed severe, life-threatening hyperkalaemia, the first following treatment with spironolactone, the second during treatment for staphylococcal septicaemia when glucose-induced hyperkalaemia occurred. Investigations demonstrated co-existing hyporeininaemic hypoaldosteronism. Prompt recognition of this combined hormone-deficiency syndrome led to appropriate treatment and recovery. The biochemical features and clinical importance of hyporeninaemic hypoaldosteronism are discussed.

Since gallium arsenide (GaAs) is both piezoelectric and semiconducting, it offers the opportunity of integrating passive Rayleigh wave components with active circuits. Judged by its Rayleigh wave properties alone, GaAs is not an attractive substrate material. Its piezoelectric coupling is slightly less than quartz and its attenuation slightly higher. In spite of these shortcomings, much effort has been expended to develop surface acoustic wave (SAW) components on GaAs for integration with electronics. This paper will review surface acoustic wave technology on gallium arsenide considering SAW propagation characteristics, transduction techniques, and unique device structures afforded by the piezoelectric semiconductor properties.

Convolution has been performed at 800 MHz and 1 GHz on Y cut, Z propagating and 38° (rotated from +Z) cut, X propagating lithium niobate, respectively. No saturation of the convolved output was observed for an acoustic power of 178 mW/mm. An attenuation of 1.4±0.3 dB/μsec due to a 500‐A Al film was measured at 1 GHz.