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344 results on '"Carpenter, D. L"'

165. Relations between Ad LibitumIntake of Several Forage Species and Gut Fill

Author

Ingalls, J. R., Thomas, J. W., Tesar, M. B., and Carpenter, D. L.

Abstract

Wethers receiving several forages were slaughtered and their rumen contents examined to ascertain the relationships between dry matter (DM), cell wall constituents (CWC), fiber and lignin content and ad libitumconsumption. Intake of DM, fiber and lignin was higher (P<.05) for sheep receiving alfalfa and trefoil compared with bromegrass and canarygrass. Rumen digesta from sheep receiving the legumes tended to contain larger amounts and a larger percent of fiber and lignin than those receiving bromegrass or canarygrass. Lignin content of the forages or total intake of fiber or lignin did not appear to limit consumption. DM and CWC in the rumen 6 hr. after feeding did not appear to be related to ad libitumDM intake. DM and CWC in the rumen 12 hr. after feeding may be related to DM intake of sheep receiving forage at 12-hr. intervals. However, the relation between amount of DM in the rumen and intake was not clear-cut and indicated that there probably were other factors playing a role in controlling ad libitumintake of high quality hays.Rumen retention time of DM was about 0.65 days for legumes and 1 day for grasses. Rumen retention time of lignin was greater (P<.05) than that of fiber, and fiber retention time tended to be greater than that of DM. Average retention time of CWC appeared to be about the same as that of DM. As DM, fiber and lignin intake increased, retention time of each constituent decreased. Further studies on the above relation are necessary to separate cause and effect.Calculated removal rate of DM, CWC, fiber and lignin from the rumen during 1 to 6 and 6 to 12 hr. postprandial indicate some differences among the different forages.Rumen digesta from sheep fed alfalfa contained a higher (P<.05) concentration and molar percent of butyrate than that of sheep fed canarygrass. Concentration of acetate, propionate and butyrate in rumen digesta was greater (P<.05) at 6 hr. than at 12 hr. postprandial; however, there was no significant difference in molar percent of VFA's between the two time intervals. The decrease in concentration of acetate and propionate from 6 to 12 hr. postprandial tended to be greater for legumes.

Published
1966
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169. Analysis of Coordinated Observations in the Region of the Day Side Polar Cleft

Author

STANFORD UNIV CA SPACE TELECOMMUNICATIONS AND RADIOSCIENCE LAB (STAR), Carpenter, D. L., Clauer, C. R., STANFORD UNIV CA SPACE TELECOMMUNICATIONS AND RADIOSCIENCE LAB (STAR), Carpenter, D. L., and Clauer, C. R.

Abstract

The objective of the research effort has been to develop electrodynamic models of the connectivity of the dayside high latitude ionosphere with the magnetosphere and solar wind. This is accomplished through the coordinated analysis of a variety of electrodynamic observations utilizing correlative satellite and ground data acquired in the vicinity of the polar cleft. Very strong evidence is found for a direct electrical connection between utilizing large scale field-aligned currents in the cleft region reproduces many of the time varying features in the observed high latitude ionospheric electrical fields and plasma convection. The small-scale current structures and expected ionospheric signatures are examined from localized coupling which would be expected from flux transfer events. Analysis of high latitude magnetic data from an array of magnetometers around Sondre Stromfjord Greenland show impulsive events. These magnetic signatures are shown to result from pairs of small scale field-aligned current filaments moving tailward at about 4 Km/sec over the array of stations. These events, however, are inconsistent with present models of FTE current systems. Keywords: Ionospheric currents; Ionospheric plasma convection; Solar wind; Magnetosphere; Ionosphere coupling; Polar cleft.

Published
1988

171. WHISTLER-MODE PROPAGATION DATA NO. 2

Author

STANFORD UNIV CA STANFORD ELECTRONICS LABS, Carpenter, D. L., Carpenter, G. B., STANFORD UNIV CA STANFORD ELECTRONICS LABS, Carpenter, D. L., and Carpenter, G. B.

Abstract

Routine data on whistler dispersion and on whistler-mode echoes from VLF-pulse transmissions are tabulated. The whistler data were obtained at Stanford, California 1 July to 31 December 1961), at Seattle, Washington (1 July to 31 October 1961 and 1 to 31 December 1961), and at Logan, Utah (1 to 30 November 1961). Data are sampled on a daily basis. The times of occurrence, values of dispersion at 5 kc, and the frequency and travel time at the whistler nose are tabulated. Data on whistler-mode echoes from VLF station NPG (Jim Creek, Washington, 18.6 kc) were obtained at Stanford, California. Hourly values of two-hop echo travel time, activity index, and quality factor for the period 1 November to 31 December 1961 are tabulated.

Published
1963

194. U.S.A. National Committee Report, Fifteenth URSI General Assembly, Munich, September 1966: Commission 4,Magnetospheric Radio; Progress in Magnetospheric Radio

Author

Johnson, Francis S., primary, Bowles, K. L., additional, Brace, L. H., additional, Carpenter, D. L., additional, Cohen, R., additional, Feier, J. A., additional, Hanson, W. B., additional, Helliwell, R. A., additional, Scarf, F. L., additional, Smith, R. L., additional, and Sugiura, M., additional

Published
1966
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200. On the occurrence of ground observations of ELF/VLF magnetospheric amplification induced by the HAARP facility

Author

İnan, Umran Savaş (ORCID 0000-0001-5837-5807 & YÖK ID 177880), Golkowski, M., Cohen, M. B., Carpenter, D. L., College of Engineering, and Department of Electrical and Electronics Engineering

Subjects
Astronomy and astrophysics, Physics::Space Physics, Scale irregularities, Electron-density, Chorus emissions, Vlf signals, Whistler, Plasmapause, Diagnostics, Ionization, Growth, Waves
Abstract

The ionospheric heating facility of the High Frequency Active Auroral Research Program (HAARP) has been used extensively in the last 3 years for injection of ELF/VLF waves into the magnetosphere via modulated heating of the overhead auroral electrojet currents. Of particular interest are waves that are observed to be nonlinearly amplified after interaction with hot plasma electrons in the Earth's radiation belts. Past results have shown HAARP to be an effective platform for controlled studies of wave particle interactions in the Earth's magnetosphere. A summary of the experimental results is provided in the context of dependencies on geomagnetic conditions and transmitter parameters. It is deduced that the primary variable that is associated with successful ground observations of HAARP-induced magnetospheric amplification is availability of magnetospheric wave guiding structures. Such structures are found to be most prevalent under quiet geomagnetic conditions following a disturbance when the plasmapause extends to the latitude of the HAARP facility or higher. Strong electrojet currents and high amplitudes of generated ELF/VLF signals observed on the ground are poor indicators of observation probability on a day to day basis although variation of these variables can be important on minute and second timescales. Frequency-time formats with continuously increasing ELF/VLF frequency show preferential amplification as predicted by nonlinear theory of electron trapping. Amplification of signals is also found to be possible for signals with noncoherent bandwidths of up to 30 Hz., Office of Naval Research (ONR); Air Force Research Laboratory; Defense Advanced Research Programs Agency, via ONR

Published
2011

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