Investigation of ground reflection and impedance from flyover noise measurements

An extensive series of flyover noise tests was conducted for the primary purpose of studying meteorological effects on propagation of aircraft noise. The test airplane, a DC 9-10, flew several level-flight passes at various heights over a taxiway. Two microphone stations were located under the flight path. A total of 37 runs was selected for analysis and processed to obtain a consistant set of 1/3 octave band sound pressure levels at half-second intervals. The goal of the present study was to use the flyover noise data to deduce acoustical reflection coefficients and hence, acoustical impedances

Ground-runup tests of acoustically treated inlets and fan ducts

Ground performance tests on noise intensity of turbofan engine ducts modified by acoustic lining

Development of ion implantation techniques for microelectronics

Ion implantation process for fabricating active devices in high bandgap semiconductor materials for high temperature operatio

New results on GP Com

We present high resolution optical and UV spectra of the 46 min orbital period, helium binary, GP Com. Our data contains simultaneous photometric correction which confirms the flaring behaviour observed in previous optical and UV data. In this system all lines show a triple peaked structure where the outer two peaks are associated with the accretion disc around the compact object. The main aim of this paper is to constrain the origin of the central peak, also called ``central spike''. We find that the central spike contributes to the flare spectra indicating that its origin is probably the compact object. We also detect that the central spike moves with orbital phase following an S-wave pattern. The radial velocity semiamplitude of the S-wave is ~10 km/s indicating that its origin is near the centre of mass of the system, which in this case lies very close to the white dwarf. Our resolution is higher than that of previous data which allows us to resolve structure in the central peak of the line. The central spike in three of the HeI lines shows another peak blueshifted with respect to the main peak. We propose that one of the peaks is a neutral helium forbidden transition excited in a high electron density region. This forbidden transition is associated with the permitted one (the stronger peak in two of the lines). The presence of a high electron density region again favours the white dwarf as their origin.Comment: 14 pages, 16 figures. Accepted for publication in A&

EAM Modulated DBR Laser Array for TWDM-PON Applications

4 Channel DBR laser arrays are fabricated for use in optical line terminals of TWDM-PON systems. These combine 1.4Q InGaAsP material in the DBR with EAMs using the identical active layer design. A tuning range ~10 nm and extinction ratio of >27 dB are measured

Site-Specific Research Conducted in Support of the Salton Sea Solar Pond Project - FY 1982 Report

The design and operation of a salt-gradient solar pond power plant at the Salton Sea presents problems not encountered at small research ponds that were built in the United States. The specific characteristics of the Salton Sea site and the desire to construct the pond using the local clay as a sealant represent major deviations from previous solar pond experience. The site-specific research in support of the plant design is described. The research activity included validation of the spectrophotometric light transmission measurement technique, a search for options for clarifying the turbid and colored water of the Salton Sea, development of water clarification specifications in terms common to industry practice, quantification of gas production from microbiological reactions in the ground, a determination of the combined effects of temperature and salinity on the permeation of the local clays, and a preliminary evaluation of material corrosion

Investigation of DC-8 nacelle modifications to reduce fan-compressor noise in airport communities. Part 2 - Design studies and duct-lining investigations, May 1967 - October 1969

Modifications to reduce fan-compressor noise level of DC-8 aircraft - Part

Solar pond power plant feasibility study for Davis, California

The feasibility of constructing a solar pond power plant at Davis, California was studied. Site visits, weather data compilation, soil and water analyses, conceptual system design and analyses, a material and equipment market survey, conceptual site layout, and a preliminary cost estimate were studied. It was concluded that a solar pond power plant is technically feasible, but economically unattractive. The relatively small scale of the proposed plant and the high cost of importing salt resulted in a disproportionately high capital investment with respect to the annual energy production capacity of the plant. Cycle optimization and increased plant size would increase the economical attractiveness of the proposed concept