Portable digital pressure indicator for calibrating magnetic tape recorders

The design of a portable Digital Pressure Indicator (DPI) to be used for calibrating the pressure systems on Langley's magnetic tape recorders is described. High-speed magnetic tape recorders require pressure (0 to 20 psig) for providing an air cushion across the tape guides and a slight vacuum (30 inch H2O) for maintaining the proper number of tape loops in the advance and feed chamber. The DPI is a hand-held device that can be quickly coupled to a magnetic tape recorder and includes a two-position switch for selecting either measured pressure or vacuum, to be displayed digitally in engineering units (psig or inches H2O). The DPI is currently in use in Langley's Analysis and Computation Division

Modulated infrared radiant source

A modulated, infrared radiant energy source was developed to calibrate an airborne nadir-viewing pressure modulated radiometer to be used to detect from Earth orbit trace gases in the troposphere. The technique used an 8 cm long, 0.005 cm diameter platinum-iridium wire as an isothermal, thin line radiant energy source maintained at 1200 K. A + or - 20 K signal, oscillating at controllable frequencies from dc to 20 Hz, was superimposed on it. This periodic variation of the line source energy was used to verify the pressure modulated radiometer's capability to distinguish between the signal variations caused by the Earth's background surface and the signal from the atmospheric gases of interest

Field trips and resource visitors available to the Natick, Massachusetts elementary schools

Thesis (Ed.M.)--Boston Universit

Data acquisition system for NASA LaRC impact dynamics research facility

A data system is designed to permit the simultaneous recording of 90 data channels on one 28 track magnetic tape recorder using a constant bandwidth FM multiplexing technique. Dynamic signals from transducers located in the test aircraft are amplified and fed to voltage controlled oscillators where they are converted to discrete FM signals. The signals from each group of five VCO's are fed to a mixer/distribution amplifier where they are combined into one composite signal and recorded, using direct recording techniques, on one magnetic tape recorder track. Millivolt signals from the recorders reproduce heads are amplified to one volt and then electronically switched to an FM demultiplexing system where appropriate frequency discrimination and signal filtering recover the original analog information

Experimental observation of superluminal group velocities in bulk two-dimensional photonic bandgap crystals

We have experimentally observed superluminal and infinite group velocities in bulk hexagonal two-dimensional photonic bandgap crystals with bandgaps in the microwave region. The group velocities depend on the polarization of the incident radiation and the air-filling fraction of the crystal.Comment: 8 pages, 7 figure

The contribution of multi-sensory aids to a meaningful art program.

Thesis (Ed.M.)--Boston Universit

Electrophoretic Analyses of Serum Proteins of the Albino Rat

Author Institution: Department of Biology, Bowling Green State University, Bowling Green, Ohio 43403Study of the leukemias and polycythemia has been complicated by the inability to isolate pure preparations of suspected "control factors" of hemopoiesis. The presence in rat serum of a factor controlling granulocyte maturation in rat bone-marrow has been demonstrated, but precise analysis has not been possible because of the lack of clear identification of rat-serum proteins. This study analyzes serum proteins of the albino rat through relative electrophoretic mobilities and specific staining. Pooled rat- and human-serum samples were fractionated by gel nitration on Sephadex G-200. The resulting fractions were further separated by vertical discontinuous polyacrylamide gel electrophoresis. Identification of proteins was based on relative mobility and on reactions with general portein, glycoprotein, lipoprotein, and haptoglobin stains. The low-molecular-weight fraction (MW 5,000-150,000) of rat serum contained prealbumin, albumin, three alpha-1, five alpha-2, and two beta globulins, and two alpha lipoproteins. The three alpha-1 globulins were implicated as a possible maturation factor. The slowest alpha-2 globulin was shown to be a haptoglobin. The intermediate-molecularweight fraction (MW 150,000-300,000) was composed of two gamma globulins, a benzidinepositive alpha-2 globulin, two alpha-1 globulins, and an alpha lipoprotein component. The high-molecular-weight fraction (MW 300,000+) contained a beta-lipoprotein, two gamma macroglobulins, and two alpha-1 macroglobulins. Further diffuse staining was present in the gamma region. All of the non-lipoproteins in these two fractions were glycoproteins. Mobilities of the major identifiable human-serum proteins (prealbumin, albumin, gamma globulin, haptoglobin) were similar to the same proteins in the rat, although many differences were apparent. Human albumin and prealbumin formed a separate fourth fraction which was not found in the rat

Comparison of in situ aerosol measurements with SAGE 2 and SAM 2 aerosol measurements during the airborne Antarctic ozone experiment

Models indicate that stratospheric aerosols play a major role in the destruction of ozone during the Austral winter. Although many in situ measurements of stratospheric aerosols were made during the Airborne Antarctic Ozone Experiment, changes of aerosol concentration and size distributions across the polar vortex are important to understanding changes of chemical species taking place during this time. Therefore comparing the in situ measurements with measurements made by satellites scanning wider areas will give a clearer picture of the possible role played by aerosols during this period. The wire impactor size distributions are compared to those from the aerosol spectrometers and a best fit size distribution determined. Aerosol extinctions are calculated from the in situ measurements and compared to the extinctions measured by the satellites. Five comparisons are made with SAGE 2 and four with SAM 2. Extinctions agree as close as a factor of two

Resonant behaviour of an oscillating wave energy converter in a channel

A mathematical model is developed to study the behaviour of an oscillating wave energy converter in a channel. During recent laboratory tests in a wave tank, peaks in the hydrodynamic actions on the converter occurred at certain frequencies of the incident waves. This resonant mechanism is known to be generated by the transverse sloshing modes of the channel. Here the influence of the channel sloshing modes on the performance of the device is further investigated. Within the framework of a linear inviscid potential-flow theory, application of the Green theorem yields a hypersingular integral equation for the velocity potential in the fluid domain. The solution is found in terms of a fast-converging series of Chebyshev polynomials of the second kind. The physical behaviour of the system is then analysed, showing sensitivity of the resonant sloshing modes to the geometry of the device, that concurs in increasing the maximum efficiency. Analytical results are validated with available numerical and experimental data.Comment: Accepted for publicatio