Propellant slosh coupling with bending Interim report

Vibrational characteristics of large liquid propellant space vehicl

MODELING NONNEGATIVITY VIA TRUNCATED LOGISTIC AND NORMAL DISTRIBUTIONS: AN APPLICATION TO RANCH LAND PRICE ANALYSIS

This study presents an empirical method of modeling the nonnegativity of dependent variables using truncated logistic and normal disturbance distributions. The method is applied in estimating a ranch land hedonic price function. Results show that the degree of truncation is significant.Land Economics/Use,

Global behavior of cosmological dynamics with interacting Veneziano ghost

In this paper, we shall study the dynamical behavior of the universe accelerated by the so called Veneziano ghost dark energy component locally and globally by using the linearization and nullcline method developed in this paper. The energy density is generalized to be proportional to the Hawking temperature defined on the trapping horizon instead of Hubble horizon of the Friedmann-Robertson-Walker (FRW) universe. We also give a prediction of the fate of the universe and present the bifurcation phenomenon of the dynamical system of the universe. It seems that the universe could be dominated by dark energy at present in some region of the parameter space.Comment: 8 pages, 7 figures, accepted for publication in JHE

Low Voltage Nanoelectromechanical Switches Based on Silicon Carbide Nanowires

We report experimental demonstrations of electrostatically actuated, contact-mode nanoelectromechanical switches based on very thin silicon carbide (SiC) nanowires (NWs). These NWs are lithographically patterned from a 50 nm thick SiC layer heteroepitaxially grown on single-crystal silicon (Si). Several generic designs of in-plane electrostatic SiC NW switches have been realized, with NW widths as small as ~20 nm and lateral switching gaps as narrow as ~10 nm. Very low switch-on voltages are obtained, from a few volts down to ~1 V level. Two-terminal, contact-mode “hot” switching with high on/off ratios (>10^2 or 10^3) has been demonstrated repeatedly for many devices. We find enhanced switching performance in bare SiC NWs, with lifetimes exceeding those based on metallized SiC NWs

Temporal and Spectral Correlations of Cyg X-1

Temporal and spectral properties of X-ray rapid variability of Cyg X-1 are studied by an approach of correlation analysis in the time domain on different time scales. The correlation coefficients between the total intensity in 2-60 keV and the hardness ratio of 13-60 keV to 2-6 keV band on the time scale of about 1 ms are always negative in all states. For soft states, the correlation coefficients are positive on all the time scales from about 0.01 s to 100 s, which is significantly different with that for transition and low states. Temporal structures in high energy band are narrower than that in low energy band in quite a few cases. The delay of high energy photons relative to low energy ones in the X-ray variations has also been revealed by the correlation analysis. The implication of observed temporal and spectral characteristics to the production region and mechanism of Cyg X-1 X-ray variations is discussed.Comment: 17 pages, 6 figures included, to appear in Ap