A 15.3 GHz satellite-to-ground diversity propagation experiment using a terminal separation of 4 kilometers

The performance of a path diversity satellite-to-ground millimeter wave link with two ground terminals separated by 4 km is discussed. At this separation distance the duration of fades below 6 dB was decreased by at least a factor of 10 when using path diversity and the cumulative crosscorrelation between the attenuations observed at the two terminals during rain events was approximately 0.45. Narrow beam radiometers directed along the propagation paths were also utilized to relate the path radiometric temperature to the path attenuation. An analysis of downlink propagation data for generating diversity link performance statistics is included

Theoretical study of the ballistics and heat transfer in spinning solid propellant rocket motors

Computerized prediction analyses of radial spin acceleration effects on solid propellant rocket motor ballistics and heat transfe

A Theory for steady and self-sustained premixed combustion waves

Based on the compressible Navier – Stokes equations for reactive flow problems, an eigenvalue problem for the steady and self-sustained premixed combustion wave propagation is developed. The eigenvalue problem is analytically solved and a set of analytic formulae for description of the wave propagation is found out. The analytic formulae are actually the exact solution of the eigenvalue problem in the form of integration, based on which author develops an iterative and numerical algorithm for calculation of the steady and self-sustained premixed combustion wave propagation and its speed. In order to explore the mathematical model and test the computational method developed in this paper, three groups of combustion wave propagation modes are calculated. The computational results show that the non-trivial modes of the combustion wave propagation exist and their distribution is not continuous but discrete

Implicit Theories of Mental Toughness: Relations With Cognitive, Motivational, and Behavioral Correlates

People differ in their implicit theories about mental toughness, that is, whether they believe this quality is immutable (entity theorists) or changeable (incremental theorists). The aim of this study was to explore whether peoples’ implicit theories of mental toughness are related to cognitive, motivational, and behavioral variables considered as hallmarks of this personal quality. We conducted 3 studies with participants from different achievement contexts: 444 undergraduate students aged 17 to 26 years (M 19.25); 395 employees aged 25 to 79 years (M 48.78); and 230 adolescent athletes aged 11 to 17 years (M 14.98). Students completed a measure of implicit theories of mental toughness, fear of failure, and perceived stress. Employees completed a measure of implicit theories and were rated on performance and creativity by their supervisor. Athletes completed a measure of implicit theories of mental toughness, resilience, and thriving. Across all 3 samples, cluster analyses supported the existence of an incremental theory (high incremental theory, low entity theory) alongside an ambivalent group (moderate scores on both theories). These clusters differed on fear of failure, stress, performance, creativity, resilience, and thriving consistent with theoretical expectations. The current findings suggest that people’s implicit theories of mental toughness may have important implications for understanding cognitive, motivational, and behavioral correlates considered hallmarks of this psychological concept

Integral field spectroscopy of nearby QSOs II. The molecular gas content and condition for star formation

We present single-dish 12CO(1 − 0) and 12CO(2 − 1) observations for 14 low-redshift quasi-stellar objects (QSOs). In combination with optical integral field spectroscopy we study how the cold gas content relates to the star formation rate (SFR) and black hole accretion rate. 12CO(1 − 0) is detected in 8 of 14 targets and 12CO(2 − 1) is detected in 7 out of 11 cases. The majority of disc-dominated QSOs reveal gas fractions and depletion times well matching normal star forming systems. Two gas-rich major mergers show clear starburst signatures with higher than average gas fractions and shorter depletion times. Bulge-dominated QSO hosts are mainly undetected in 12CO(1 − 0) which corresponds, on average, to lower gas fractions than in disc-dominated counterparts. Their SFRs however imply shorter than average depletion times and higher star formation efficiencies. Negative QSO feedback through removal of cold gas seems to play a negligible role in our sample. We find a trend between black hole accretion rate and total molecular gas content for disc-dominated QSOs when combined with literature samples. We interpret this as an upper envelope for the nuclear activity and is well represented by a scaling relation between the total and circum-nuclear gas reservoir accessible for accretion. Bulge-dominated QSOs significantly differ from that scaling relation and appear uncorrelated with the total molecular gas content. This could be explained either by a more compact gas reservoir, blow out of the gas envelope through outflows, or a different ISM phase composition

Uncertainty analysis of diffuse-gray radiation enclosure problems: A hypersensitive case study

An uncertainty analysis of diffuse-gray enclosure problems is presented. The genesis was a diffuse-gray enclosure problem which proved to be hypersensitive to the specification of view factors. This genesis is discussed in some detail. The uncertainty analysis is presented for the general diffuse-gray enclosure problem and applied to the hypersensitive case study. It was found that the hypersensitivity could be greatly reduced by enforcing both closure and reciprocity for the view factors. The effects of uncertainties in the surface emissivities and temperatures are also investigated