7,580 research outputs found
Space shuttle electromagnetic environment experiment. Phase A: Definition study
Methods for carrying out measurements of earth electromagnetic environment using the space shuttle as a measurement system platform are herein reported. The goal is to provide means for mapping intentional and nonintentional emitters on earth in the frequency range 0.4 to 40 GHz. A survey was made of known emitters using available data from national and international regulatory agencies, and from industry sources. The spatial distribution of sources, power levels, frequencies, degree of frequency re-use, etc., found in the survey, are here presented. A concept is developed for scanning the earth using a directive antenna whose beam is made to rotate at a fixed angle relative to the nadir; the illuminated area swept by the beam is of the form of cycloidal annulus over a sphere. During the beam's sojourn over a point, the receiver sweeps in frequency over ranges in the order of octave width using sweeping filter bandwidths sufficient to give stable readings
Editorially Speaking
This is the last issue of the I.8.C. Veterinarian with which the members of the senior class will be actively concerned. Several of these men have worked for the publication for four years. Although the editor and business manager are responsible for the editorial and financial success of the publication, they can do nothing without the constant assistance and cooperation of the respective staffs. It is appropriate, therefore, that we gratefully acknowledge the work of our assistants
Report of the direct infrared sensors panel
The direct infrared sensors panel considered a wide range of options for technologies relevant to the science goals of the Astrotech 21 mission set. Among the technologies assessed are: large format arrays; photon counting detectors; higher temperature 1 to 10 micro-m arrays; impurity band conduction (IBC) or blocked impurity band (BIB) detectors; readout electronics; and adapting the Space Infrared Telescope Facility and Hubble Space Telescope. Detailed development plans were presented for each of these technology areas
Space shuttle electromagnetic environment experiment. Phase A: Definition study
A program is discussed which develops a concept for measuring the electromagnetic environment on earth with equipment on board an orbiting space shuttle. Earlier work on spaceborne measuring experiments is reviewed, and emissions to be expected are estimated using, in part, previously gathered data. General relations among system parameters are presented, followed by a proposal on spatial and frequency scanning concepts. The methods proposed include a nadir looking measurement with small lateral scan and a circularly scanned measurement looking tangent to the earth's surface at the horizon. Antenna requirements are given, assuming frequency coverage from 400 MHz to 40 GHz. For the low frequency range, 400-1000 MHz, a processed, thinned array is proposed which will be more fully analyzed in the next phase of the program. Preliminary hardware and data processing requirements are presented
A Transportation Alliance of Environmental Horticulture Producers in Georgia: Issues and Feasibility
Transportation and shipping costs of ornamental horticulture are 10% of total cost of production in Georgia. With many small to medium sized producers using their own independent transportation system, methods to optimize vehicle operations are desired. Will a transportation alliance reduce shipping costs, increase distribution efficiencies, and reduce carbon dioxide emissions among ornamental plants producers in Georgia? The study shows alliances are not only feasible, they have average total cost savings of 9%, average total miles driven savings of 8%, average number of trucks savings of 8%, average driving hours savings of 15%, and average carbon dioxide emissions savings of 8%.transportation, logistics, efficiencies, savings, environmental horticulture, Agribusiness,
- …