Radio aurora magnetic and streaming aspect sensitivities on 6 simultaneous links at 50 MHz

During August 1981, a 50 MHz c.w. radar system was operated in central Canada to measure auroral scatter amplitudes and Doppler spectra from a scattering region centered near 66° magnetic invariant latitude (L ≈ 6.0). Narrow beams from 3 transmitters, differing in frequency by 1 KHz, were directed to cover a common volume of the ionosphere over a ground location at 56.3°N, 103.5°W. The scattered signals were received on narrow beam antennas at two receiving sites, and recorded in analog form on magnetic tape under the control of an AIM65 microcomputer. The analog tapes were digitized later and FFT-processed to obtain Doppler spectra and amplitudes.The 6 transmission paths were designed to provide several magnetic aspect angles varying by 1.5°-7° from perpendicularity with the earth's field B and two streaming aspect angles differing by ～38°. The objective was to employ controlled geometric factors to study the functional dependency of signal amplitudes and Doppler shifts on magnetic and streaming aspect angles. Several hundred hours of excellent data were obtained in continuous operation during the month of August 1981. Preliminary results will be reported.     

America's Abundant Electricity and the ASME Boiler Code

The building of great steam power plants with utmost consideration for public safety has created today's American miracle of abundant electricity. Behind this great achievement stand the mechanical engineers who have designed and built these power plants under their ethical responsibilities for public safety, in full compliance with the American Society of Mechanical Engineers (ASME) Boiler Code and under the strict disciplines imposed by a specialist insurance company willing to write 100 percent insurance coverage against boiler explosions. The historical origin of this great achievement dates back to the days of the Civil War and a small group of men with exceptional vision and a profound concern for public safety. They saw the opportunity to apply their talents and sense of responsibility to solving the problem of steam boiler explosions and the terrible losses of human lives. These early leaders have earned the esteem and honor of our present and future generations, but who remembers them? Today, in the scientific revolution of this century, there is a critical need for similar new leaders of exceptional integrity, responsibility, and initiative, both in engineering and in industry.     

Analysis of gravity-wave induced instabilities and turbulence viscosity parameters from optical emissions

The effects of gravity waves on OH and 5577 0I emissions have been used to investigate (1) the possible production of “secondary” waves or “ripples” by a “primary” wave; (2) the possible application of such observed optical emissions for computing atmospheric parameters such as turbulence viscosity in the mesospheric regions.     

Supernova remnants

Optical observations of young supernova remnants can give information on the abundance structure of the supernova ejecta, from which properties of the supernova explosion can be deduced. Young remnants also act as laboratories for fast shock wave phenomena. Observations of X-ray and optical line emission show that while a collisionless shock wave does form, it is far from thermal equilibrium. Some young remnants are promising candidates for particle acceleration in shock waves, while in other remnants a central compact object is probably responsible for particle acceleration.     

Sea surface temperature measurement from satellites: Validation and accuracy

A review of the latest published results concerning the accuracy of satellite derived sea surface temperature (SST) estimation is presented. Two types of platforms are considered : orbiting satellites and geosynchronous satellites and the accuracies that may now be expected from such systems are reported. This review emphasizes the impressive improvement in global mapping of SST obtained from the Advanced Very High Resolution Radiometer (AVHRR) on NOAA's operational polar satellites. Tests of the AVHRR SST's against a high reliability data set consisting of buoys, bathythermographs and research ship reports indicate biases of < 0.1°C and RMS differences of < 0.75°C (McClain [1]). Particular attention is also paid to a method adding along track scanning capability to the present multichannel AVHRR technique. This method is demonstrated owing to the coupling of an orbiting satellite (TIROS-N) and a geosynchronous satellite (METEOSAT). Another type of coupling of two such platforms is also presented in connection with the advent of geostationary satellites equipped with a vertical sounding capability, such as GOES-4.     

A directed search for extraterrestrial laser signals

This paper analyzes the technical feasibility of interstellar communication at infrared frequencies, both in its own right and in comparison with communication at radio frequencies. The analysis considers both the practical and fundamental limits affecting communication over interstellar distances and concludes that for specified transmitter and receiver locations communications at infrared and radio frequencies can be equally effective. On this basis a search for extraterrestrial signals at infrared wavelengths is equally as valid as any planned microwave effort. Work is now in progress to adapt a 10 micrometers heterodyne spectrometer to search for CO2 laser signals from 200 nearby stars.     

Stabilization of Precision Electrooptical Pointing and Tracking Systems

This paper presents the pointing vector and angular rate relationshipsfor various optical elements as well as techniques developed forestablishing comprehensive analytical models of precision electroopticalstabilization systems. Since the performance of such systemsmay be critically dependent on the disturbance environment and theintegrity of the associated mechanism, these factors are also examinedin detail.     

Analysis of the Switched Self-Balancing Comparsion Radiometer

Analysis of the switched self-balancing comparison radiometer with coupling between the channels is given. The comparison source is a stationary, zero-mean white noise generator of known spectral density. An expression for the power spectrum at the output of the radiometer is derived. It is shown that measurement errors due to interchannel coupling can be corrected by phase switching. Radiometer sensitivity is also calculated. The switched version of the radiometer has been simulated at low frequencies and is under construction at X-band.     

One-kVA, Three-Phase dc-ac Inverter with Digital Control

This paper describes a method of applying digital techniques to the control of a 1-kVA three-phase dc-ac inverter to generate a sinusoidal 400-Hz output, using high-frequency bridge-chopper techniques. The model which was constructed used predominantly off-theshelf digital microcircuits and resulted in a device with an overall efficiency of 85 percent, in a 0.52 cubic-foot package which weighed 19.5 lbs. Sinusoidal output with less than 2 percent harmonic distortion at 115 volts line to neutral was obtained with 28 volts dc input.