Single stage experimental evaluation of slotted rotor and stator blading. Part I - Analysis and design

Analysis and design of slotted rotor and stator blading for application to compressors in advanced airbreathing propulsion system

The Effect of Repetitive Feedings on the Acceptability of Selected Metabolic Diets

Effect of repetitive feeding over extended periods of time on acceptability of selected metabolic diet

The time evolution of cosmological redshift as a test of dark energy

The variation of the expansion rate of the Universe with time produces an evolution in the cosmological redshift of distant sources (for example quasar Lyman-$\alpha$ absorption lines), that might be directly observed by future ultra stable, high-resolution spectrographs (such as CODEX) coupled to extremely large telescopes (such as European Southern Observatory's Extremely Large Telescope, ELT). This would open a new window to explore the physical mechanism responsible for the current acceleration of the Universe. We investigate the evolution of cosmological redshift from a variety of dark energy models, and compare it with simulated data. We perform a Fisher matrix analysis and discuss the prospects for constraining the parameters of these models and for discriminating among competing candidates. We find that, because of parameter degeneracies, and of the inherent technical difficulties involved in this kind of observations, the uncertainties on parameter reconstruction can be rather large unless strong external priors are assumed. However, the method could be a valuable complementary cosmological tool, and give important insights on the dynamics of dark energy, not obtainable using other probes.Comment: 9 pages, 2 figures. Matching published versio

Strong Gravitational Lensing and Dark Energy Complementarity

In the search for the nature of dark energy most cosmological probes measure simple functions of the expansion rate. While powerful, these all involve roughly the same dependence on the dark energy equation of state parameters, with anticorrelation between its present value w_0 and time variation w_a. Quantities that have instead positive correlation and so a sensitivity direction largely orthogonal to, e.g., distance probes offer the hope of achieving tight constraints through complementarity. Such quantities are found in strong gravitational lensing observations of image separations and time delays. While degeneracy between cosmological parameters prevents full complementarity, strong lensing measurements to 1% accuracy can improve equation of state characterization by 15-50%. Next generation surveys should provide data on roughly 10^5 lens systems, though systematic errors will remain challenging.Comment: 7 pages, 5 figure

Surface-micromachined Ta–Si–N beams for use in micromechanics

Realization and characterization of free-standing surface-microstructures based on Ta-Si-N films are presented. Due to their significant physical and chemical properties, such ternary films are promising candidates for application in microelectromechanical devices

Evaluation of trends in derived snowfall and rainfall across Eurasia and linkages with discharge to the Arctic Ocean

To more fully understand the role of precipitation in observed increases in freshwater discharge to the Arctic Ocean, data from a new archive of bias-adjusted precipitation records for the former USSR (TD9813), along with the CRU and Willmott-Matsuura data sets, were examined for the period 1936–1999. Across the six largest Eurasian river basins, snowfall derived from TD9813 exhibits a strongly significant increase until the late 1950s and a moderately significant decrease thereafter. A strongly significant decline in derived rainfall is also noted. Spatially, snowfall increases are found primarily across north-central Eurasia, an area where the rainfall decreases are most prominent. Although no significant change is determined in Eurasian-basin snowfall over the entire 64 year period, we note that interpolation from early, uneven station networks causes an overestimation of spatial precipitation, and that the local snowfall trends determined from gridded TD9813 data are likely underestimated. Yet, numerous uncertainties in historical Arctic climate data and the sparse, irregular nature of Arctic station networks preclude a confident assessment of precipitation-discharge linkages during the period of reported discharge trends

Exploring the Expanding Universe and Dark Energy using the Statefinder Diagnostic

The coming few years are likely to witness a dramatic increase in high quality Sn data as current surveys add more high redshift supernovae to their inventory and as newer and deeper supernova experiments become operational. Given the current variety in dark energy models and the expected improvement in observational data, an accurate and versatile diagnostic of dark energy is the need of the hour. This paper examines the Statefinder diagnostic in the light of the proposed SNAP satellite which is expected to observe about 2000 supernovae per year. We show that the Statefinder is versatile enough to differentiate between dark energy models as varied as the cosmological constant on the one hand, and quintessence, the Chaplygin gas and braneworld models, on the other. Using SNAP data, the Statefinder can distinguish a cosmological constant ($w=-1$) from quintessence models with $w \geq -0.9$ and Chaplygin gas models with $\kappa \leq 15$ at the $3\sigma$ level if the value of \om is known exactly. The Statefinder gives reasonable results even when the value of \om is known to only $\sim 20$ accuracy. In this case, marginalizing over \om and assuming a fiducial LCDM model allows us to rule out quintessence with $w \geq -0.85$ and the Chaplygin gas with $\kappa \leq 7$ (both at $3\sigma$). These constraints can be made even tighter if we use the Statefinders in conjunction with the deceleration parameter. The Statefinder is very sensitive to the total pressure exerted by all forms of matter and radiation in the universe. It can therefore differentiate between dark energy models at moderately high redshifts of z \lleq 10.Comment: 21 pages, 17 figures. Minor typos corrected to agree with version published in MNRAS. Results unchange

From incus bypass to malleostapedotomy: technical improvements and results

Abstract Objective: To assess results of malleostapedotomy using a Fisch Storz titanium piston with at least 10 months' follow up. Methods: Using a prospective database, the indications, surgical technique, and pre- and post-operative audiometric data for 60 patients undergoing malleostapedotomy between 2002 and 2010 were evaluated. Diagnoses and primary and revision surgeries were compared with reference to the literature. Results: Sixty endaural malleostapedotomies were performed, 28 as a primary intervention and 32 as revision surgery. In 68 per cent, the underlying pathology was otosclerosis. The most common reason for revision surgery (i.e. in 59 per cent) was prosthesis dysfunction. Overall, the mean air-bone gap (0.5-3kHz) for the primary intervention and revision surgery groups was 9.4 and 11.3dB, respectively; an air-bone gap of less than 20dB was obtained in 100 and 81 per cent of patients, respectively. There was no significant audiological difference between the primary and revision surgeries groups, and no deafness. Conclusion: Malleostapedotomy shows comparable results to standard incus-stapedotomy and may be preferable in the presented situation

Comparison of organoleptic acceptability of liquid and fresh diets

Organoleptic acceptability of liquid and fresh diets for space flight feedin

Cosmic Shear with Next Generation Redshift Surveys as a Cosmological Probe

The expansion of the universe causes spacetime curvature, distinguishing between distances measured along and transverse to the line of sight. The ratio of these distances, e.g. the cosmic shear distortion of a sphere defined by observations of large scale structure as suggested by Alcock & Paczynski, provides a method for exploring the expansion as a function of redshift. The theoretical sensitivity to cosmological parameters, including the dark energy equation of state, is presented. Remarkably, sensitivity to the time variation of the dark energy equation of state is best achieved by observations at redshifts z<1. While systematic errors greatly degrade the theoretical sensitivity, this probe may still offer useful parameter estimation, especially in complementarity with a distance measure like the Type Ia supernova method implemented by SNAP. Possible future observations of the Alcock-Paczynski distortion by the KAOS project on a 8 meter ground based telescope are considered.Comment: 6 pages, 8 figure