Effect of coolant flow ejection on aerodynamic performance of low-aspect-ratio vanes. 2: Performance with coolant flow ejection at temperature ratios up to 2

The aerodynamic performance of a 0.5 aspect ratio turbine vane configuration with coolant flow ejection was experimentally determined in a full annular cascade. The vanes were tested at a nominal mean section ideal critical velocity ratio of 0.890 over a range of primary to coolant total temperature ratio from 1.0 to 2.08 and a range of coolant to primary total pressure ratio from 1.0 to 1.4 which corresponded to coolant flows from 3.0 to 10.7 percent of the primary flow. The variations in primary and thermodynamic efficiency and exit flow conditions with circumferential and radial position were obtained

Study of the system of middle atmosphere-ionosphere using remote-sensing data

In the present investigation, the methods of statistical spectral analysis are employed for a study of the quasi-periodic changes of state parameters of the middle atmosphere and the ionosphere, taking into account oscillations with periods of several days. The considered oscillations are typical for planetary waves. The theory and empirical findings regarding transient planetary waves are utilized as a basis for the concepts employed in the data analysis and for the interpretation of the results. The results of the investigation show a presence of coherent variations in the time series of radiation density measurements and other state parameters for the middle atmosphere and the ionosphere. The existence of presumably dynamic coupling processes can be recognized in oscillations with periods of about 16 or 5 days

The role of crop production clubs in technology transfer

Non-Peer ReviewedThis study was undertaken to determine if crop production club members represent an adopter category of the adoption diffusion theory as outlined by the literature, to obtain a more detailed description of the characteristics of the crop production club members and how they relate to the adopter categories and to determine the role crop production clubs play in the technology transfer process. A telephone survey was conducted using two groups, one selected from crop production clubs that had been organized for more than five years and the other a stratified random sample of non-club farmers in the surrounding area to the clubs. The questionnaire was designed to obtain information about innovative cropping practices, as well as demographic data, personal characteristics and communication behavior. A total of 38 crop production club members and 28 non-club farmers were contacted between April 22 and May 10, 1991. The results of the study found that the characteristics exhibited by crop production club members were similar to those outlined in the adoption-diffusion theory for early adopters. Therefore crop production club members fit into the adoption-diffusion process as early adopters. Crop clubs use demonstrations as a way of introducing new innovations to their club members. Both groups indicated that they used neighbors often as a source of information and therefore, crop production clubs members likely transfer information to others through this and other channels. They transfer technology through the adoption diffusion process as early adopters. From this study it can be concluded that crop production clubs do play a role in the technology transfer process

Absence of low-temperature dependence of the decay of 7Be and 198Au in metallic hosts

The electron-capture (EC) decay rate of 7Be in metallic Cu host and the beta-decay rate of 198Au in the host alloy Al-Au have been measured simultaneously at several temperatures, ranging from 0.350 K to 293 K. No difference of the half-life of 198Au between 12.5 K and 293 K is observed to a precision of 0.1%. By utilizing the special characteristics of our double-source assembly, possible geometrical effects that influence the individual rates could be eliminated. The ratio of 7Be to 198Au activity thus obtained also remains constant for this temperatures range to the experimental precision of 0.15(0.16)%. The resulting null temperature dependence is discussed in terms of the inadequacy of the often-used Debye-Huckel model for such measurements.Comment: Four pages, three figures. Accepted for publication in Phys. Rev. C (Rapd Communications

Indications of superconductivity in doped highly oriented pyrolytic graphite

We have observed possible superconductivity using standard resistance vs. temperature techniques in phosphorous ion implanted Highly Oriented Pyrolytic Graphite. The onset appears to be above 100 K and quenching by an applied magnetic field has been observed. The four initial boron implanted samples showed no signs of becoming superconductive whereas all four initial and eight subsequent samples that were implanted with phosphorous showed at least some sign of the existence of small amounts of the possibly superconducting phases. The observed onset temperature is dependent on both the number of electron donors present and the amount of damage done to the graphene sub-layers in the Highly Oriented Pyrolytic Graphite samples. As a result the data appears to suggest that the potential for far higher onset temperatures in un-damaged doped graphite exists.Comment: 7 pages, 1 table, 5 figures, 11 references, Acknowledgments section was correcte

Andreev reflections on Y1-xCaxBa2Cu3O7-delta evidence for an unusual proximity effect

We have measured Andreev reflections between an Au tip and Y_{1-x}Ca_{x}Ba_{2}Cu_{3}O_{7 - \delta} thin films in the in-plane orientation. The conductance spectra are best fitted with a pair potential having the "d_{x^{2}-y^{2}+is" symmetry. We find that the amplitude of the "is" component is enhanced as the contact transparency is increased. This is an indication for an unusual proximity effect that modifies the pair potential in the superconductor near the surface with the normal metal.Comment: 4 pages, 4 figure