scholarly journals NASA/Army/Bell XV-15 tiltrotor low noise terminal area operations flight research program

2000 ◽  
Author(s):  
David Conner ◽  
Bryan Edwards ◽  
Peter Klein ◽  
William Decker ◽  
Michael Marcolini
Keyword(s):  
Research Program ◽  
Low Noise ◽  
Terminal Area

scholarly journals NASA/Army/Bell XV-15 Tiltrotor Low Noise Terminal Area Operations Flight Research Program

2002 ◽  
Vol 47 (4) ◽  
pp. 219 ◽  
Author(s):  
David A. Conner ◽  
Bryan D. Edwards ◽  
William A. Decker ◽  
Michael A. Marcolini ◽  
Peter D. Klein
Keyword(s):  
Research Program ◽  
Low Noise ◽  
Terminal Area

RESEARCH PROGRAM ON LOW-NOISE MICROWAVE RECEIVER AMPLIFYING DEVICES

1960 ◽  
Author(s):  
A. Presser ◽  
F. Sterzer ◽  
G. Hodawanec ◽  
H. Wolkstein
Keyword(s):  
Research Program ◽  
Low Noise

Conceptual Design of a Medium-Endurance Research Vessel Optimized for Mission Flexibility and Seakeeping

1987 ◽  
Vol 24 (02) ◽  
pp. 170-192
Author(s):  
Bruce L. Hutchison ◽  
Duane H. Laible
Keyword(s):  
Conceptual Design ◽  
Research Program ◽  
General Purpose ◽  
Low Noise ◽  
Laboratory Work ◽  
Laboratory System ◽  
Noise And Vibration ◽  
Five Disciplines ◽  
The University ◽  
Large Vessels

This paper reports on a study to define a large, medium-endurance general-purpose oceangoing ship that can carry out an effective research program in any of the five disciplines (biological, chemical, geological, geophysical, and physical) that characterize modern oceanography. The general requirements specify a vessel of the same size, but of greater capability, than the present large vessels in the University-National Oceanographic Laboratory System fleet, carrying a team of about 25 researchers to most areas of the world's ocean in reasonable comfort and providing a platform that will allow more overside and laboratory work in higher sea states than is now possible. Other general requirements discussed herein include flexibility, low noise and vibration levels, and economy. The latter point requires that the emphasis on increased capability does not obscure the need to develop vessels that are economical to construct and operate.

Distribution of R- and S-Process Elements in the Galactic Halo

1988 ◽  
Vol 132 ◽  
pp. 501-506
Author(s):  
C. Sneden ◽  
C. A. Pilachowski ◽  
K. K. Gilroy ◽  
J. J. Cowan
Keyword(s):  
Heavy Element ◽  
Galactic Halo ◽  
Low Noise ◽  
Heavy Elements ◽  
Process Synthesis ◽  
Element Abundances ◽  
Halo Stars ◽  
Abundance Patterns ◽  
R Process ◽  
Process Elements

Current observational results for the abundances of the very heavy elements (Z>30) in Population II halo stars are reviewed. New high resolution, low noise spectra of many of these extremely metal-poor stars reveal general consistency in their overall abundance patterns. Below Galactic metallicities of [Fe/H] Ã −2, all of the very heavy elements were manufactured almost exclusively in r-process synthesis events. However, there is considerable star-to-star scatter in the overall level of very heavy element abundances, indicating the influence of local supernovas on element production in the very early, unmixed Galactic halo. The s-process appears to contribute substantially to stellar abundances only in stars more metal-rich than [Fe/H] Ã −2.

Tinkering with cognitive gadgets: Cultural evolutionary psychology meets active inference

2019 ◽  
Vol 42 ◽  
Author(s):  
Paul Benjamin Badcock ◽  
Axel Constant ◽  
Maxwell James Désormeau Ramstead
Keyword(s):  
Evolutionary Psychology ◽  
Research Program ◽  
Active Inference ◽  
Innovative Research ◽  
Cognitive Faculties ◽  
Cultural Evolutionary ◽  
The Relationship

Abstract Cognitive Gadgets offers a new, convincing perspective on the origins of our distinctive cognitive faculties, coupled with a clear, innovative research program. Although we broadly endorse Heyes’ ideas, we raise some concerns about her characterisation of evolutionary psychology and the relationship between biology and culture, before discussing the potential fruits of examining cognitive gadgets through the lens of active inference.

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

Quality films from carbon fiber evaporation for thorough coverage of TEM grids

1988 ◽  
Vol 46 ◽  
pp. 418-419
Author(s):  
N. Tempel ◽  
M. C. Ledbetter
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Carbon Films ◽  
Low Noise ◽  
Vacuum Evaporation ◽  
High Yield ◽  
Good Adhesion ◽  
Noise Structure ◽  
Resolution Electron ◽  
Carbon Foils

Carbon films have been a support of choice for high resolution electron microscopy since the introduction of vacuum evaporation of carbon. The desirable qualities of carbon films and methods of producing them has been extensively reviewed. It is difficult to get a high yield of grids by many of these methods, especially if virtually all of the windows must be covered with a tightly bonded, quality film of predictable thickness. We report here a method for producing carbon foils designed to maximize these attributes: 1) coverage of virtually all grid windows, 2) freedom from holes, wrinkles or folds, 3) good adhesion between film and grid, 4) uniformity of film and low noise structure, 5) predictability of film thickness, and 6) reproducibility.Our method utilizes vacuum evaporation of carbon from a fiber onto celloidin film and grid bars, adhesion of the film complex to the grid by carbon-carbon contact, and removal of the celloidin by acetone dissolution. Materials must be of high purity, and cleanliness must be rigorously maintained.

Dynamic Scanning Electron Microscopy of Small Particles

1975 ◽  
Vol 33 ◽  
pp. 280-281
Author(s):  
W. Krakow ◽  
W. C. Nixon
Keyword(s):  
Electron Microscopy ◽  
Low Noise ◽  
Time Sequence ◽  
Field Of View ◽  
Video Tape ◽  
Small Particles ◽  
Polystyrene Spheres ◽  
Field Distributions ◽  
Dynamic Scanning ◽  
Scanning Electron

The scanning electron microscope (SEM) can be run at television scanning rates and used with a video tape recorder to observe dynamic specimen changes. With a conventional tungsten source, a low noise TV image is obtained with a field of view sufficient to cover the area of the specimen to be recorded. Contrast and resolution considerations have been elucidated and many changing specimens have been studied at TV rates.To extend the work on measuring the magnitude of charge and field distributions of small particles in the SEM, we have investigated their motion and electrostatic interaction at TV rates. Fig. 1 shows a time sequence of polystyrene spheres on a conducting grating surface inclined to the microscope axis. In (la) there are four particles present in the field of view, while in (lb) a fifth particle has moved into view.

Transmission Electron Microscopy of oriented Co84Cr14Ta2 thin films for longitudinal magnetic recording

1991 ◽  
Vol 49 ◽  
pp. 756-757
Author(s):  
T. P. Nolan
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Cost ◽  
Low Noise ◽  
Information Storage ◽  
High Coercivity ◽  
Magnetic Alloy ◽  
Magnetic Media ◽  
Transmission Electron

Thin film magnetic media are being used as low cost, high density forms of information storage. The development of this technology requires the study, at the sub-micron level, of morphological, crystallographic, and magnetic properties, throughout the depth of the deposited films. As the microstructure becomes increasingly fine, widi grain sizes approaching 100Å, the unique characterization capabilities of transmission electron microscopy (TEM) have become indispensable to the analysis of such thin film magnetic media.Films were deposited at 225°C, on two NiP plated Al substrates, one polished, and one circumferentially textured with a mean roughness of 55Å. Three layers, a 750Å chromium underlayer, a 600Å layer of magnetic alloy of composition Co84Cr14Ta2, and a 300Å amorphous carbon overcoat were then sputter deposited using a dc magnetron system at a power of 1kW, in a chamber evacuated below 10-6 torr and filled to 12μm Ar pressure. The textured medium is presently used in industry owing to its high coercivity, Hc, and relatively low noise. One important feature is that the coercivity in the circumferential read/write direction is significandy higher than that in the radial direction.

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