Showing papers on "TEC published in 1980"

Equatorial electrojet control of the low latitude ionosphere.

Abstract: The role of the equatorial electrojet on the distribution of ionization at low latitudes has been discussed using mult-location Total Electron Content (TEC) data obtained through the radio beacon signals from the geostationary satellite ATS-6 and from ground-based ionosonde data. It has been found that the electrojet has a pronounced influence on TEC at latitudes extending from equator to as high as 25°N dip latitude. It is suggested that ionosphere-to-plasmasphere ionization flow plays an important role in understanding the behaviour of the equatorial TEC.

Irregular variations in the global distribution of total electron content

Abstract: The day-to-day variability of daytime total electron content (TEC) at several locations is compared to that at the mid-latitude station Hamilton for quiet as well as disturbed days in 1969. It is noticed that all these changes are seldom parallel. Sometimes, large north-south gradients are noticed, while at other times, TEC seems to pile up on either side (latitudinally) of Hamilton. On some occasions, TEC at the southern hemisphere mid-latitude is smaller than that at Hamilton for several consecutive days. It is concluded that TEC changes, at different latitudes, are neither parallel nor antiparallel in any consistent way, and large-scale random movements and/or long-lasting TEC changes, probably due to height variations, are indicated. If these are due to neutral winds, large-scale vagaries of neutral winds during quiet as well as disturbed periods (but more so during the latter) are indicated.

Potentialities of TEC topping: A simplified view of parametric effects

Abstract: An examination of the benefits of thermionic-energy-conversion (TEC)-topped power plants and methods of increasing conversion efficiency are discussed. Reductions in the cost of TEC modules yield direct decreases in the cost of electricity (COE) from TEC-topped central station power plants. Simplified COE, overall-efficiency charts presented illustrate this trend. Additional capital-cost diminution results from designing more compact furnaces with considerably increased heat transfer rates allowable and desirable for high temperature TEC and heat pipes. Such improvements can evolve of the protection from hot corrosion and slag as well as the thermal expansion compatibilities offered by silicon-carbide clads on TEC-heating surfaces. Greater efficiencies and far fewer modules are possible with high-temperature, high-power-density TEC: This decreases capital and fuel costs much more and substantially increases electric power outputs for fixed fuel inputs. In addition to more electricity, less pollution, and lower costs, TEC topping used directly in coal-combustion products contributes balance-of-payment gains.

An Investigation of the Adoption Process in Training Technology Transfer

Abstract: : This study focused on the adoption process in the transfer of Army training technology from the researcher to the user. The training product chosen for this investigation was the Training Extension Course (TEC) program. A two- part survey questionnaire was completed by 111 Army participants attending TRADOC/FORSCOM Training and Evaluation Workshops. The questionnaire requested attitudinal and usage information relating to the adoption of the Training Extension Course (TEC) program by unit training managers. Sources of TEC-related information were matched with the awareness, acceptance, and utilization stages of the adoption process to help understand the dissemination activity within training technology transfer. The attitudinal responses were factor analyzed and, with selected biographic information, were entered in a regression analysis to assess the utility of these measures as predictor variables of TEC utilization. Two major findings emerged. First, the acceptance (PERSUADE stage) of the TEC program is influenced predominantly by internal sources of information (e.g., work environment), while the initial awareness (INFORM stage) and later utilization of TEC are influenced by internal and external sources (support groups, briefings, etc.). Second, prior familiarity with TEC is a better predictor of TEC usage than are attitudinal measures taken from the innovation literature (for this particular sample).

ETS-II Experiments Part V: Effect of Ionosphere

Abstract: Propagation characteristics of gigahertz and very high frequency waves through the mid-latitude ionosphere have been studied applying the coherent beacon signals of 1.7, 11.5, and 34.5 GHz and the 136-MHz telemetry signal, which are emitted from the geostationary Engineering Test Satellite Type II (ETS-II). Total electron content (TEC) was obtained by measuring the differential phase shift between 1.7 and 11.5 GHz waves and also by the Faraday rotation of the 136-MHz carrier, the former method being more sensitive than the latter one for detecting fluctuating TEC. During the observations, amplitude scintillations at 136 MHz and 1.7 GHz, usually accompanied with an irregular variation of TEC, were recorded frequently in the nighttime and sometimes in the daytime. Specially noted is the 11.5-GHz scintillations less than 0.8 dBp-p that were observed during the severe magnetic storm on February 15, 1978, simultaneously with 136-MHz and 1.7-GHz scintillations. This was the first observation showing that the disturbed ionosphere affects waves above 10 GHz. Presented first are the techniques for the ETS-II ionospheric wave propagation experiment, including a description of the coherent receiver system in the gigahertz frequency range at Kashima and a description of the 136-MHz Faraday rotation receiver at Kokubunji. The capabilities of the facilities for monitoring the mid-latitude ionosphere by giving some observational results are then presented.

Total electron content measurements at waltair using ets ii geo-stationary satellite

Abstract: Total electron content (TEC) measurements were made at Waltair, (lat. 17.7 N, long.83.3° E) a low latitude station, using the Faraday rotation records obtained from 136.1123 MHz signals from ETS II satellite for the one year period from March 1978 to February 1979. The diurnal variation of TEC for these 12 months of observations has typically shown (a) a short-lived predawn dip around 0500 hrs L.T. (b) a steep early morning increase, (c) a broad mid-afternoon maximum with frequent noon time biteout, (d) very steep post sun set decay, (e) pre-sun set enhancement in TEC, and (f) a significant night time increase in TEC with a peak value around 2200 hrs. L.T. The seasonal variation in TEC has shown two distinct maxima around the equinoxial months (March, April and September, October), the autumnal peak being more significant. Aninteresting wave-like variation was observed in TEC with two distinct time periods.

Optimal thermionic energy conversion with established electrodes for high-temperature topping and process heating

Abstract: Applied research-and-technology (ART) work reveals that optimal thermionic energy conversion (TEC) with approximately 1000 K to approximately 1100 K collectors is possible using well established tungsten electrodes. Such TEC with 1800 K emitters could approach 26.6% efficiency at 27.4 W/sq cm with approximately 1000 K collectors and 21.7% at 22.6 W/sq cm with approximately 1100 K collectors. These performances require 1.5 and 1.7 eV collector work functions (not the 1 eV ultimate) with nearly negligible interelectrode losses. Such collectors correspond to tungsten electrode systems in approximately 0.9 to approximately 6 torr cesium pressures with 1600 K to 1900 K emitters. Because higher heat-rejection temperatures for TEC allow greater collector work functions, interelectrode loss reduction becomes an increasingly important target for applications aimed at elevated temperatures. Studies of intragap modifications and new electrodes that will allow better electron emission and collection with lower cesium pressures are among the TEC-ART approaches to reduced interelectrode losses. These solutions will provide very effective TEC to serve directly in coal-combustion products for high-temperature topping and process heating. In turn this will help to use coal and to use it well.

Day-to-day variability in the low-latitude ionosphere

Abstract: The day-to-day variability in the total electron content is studied at four low-latitude stations. The variations in daily range of the TEC are related to the changes in solar EUV flux, variation in the equatorial plasma transport under different geomagnetic conditions and the changes in the neutral densities at the F-region heights.