Condensers and or evaporators in convective and radiative environments

Condensers and/or evaporators in convective and radiative environment

Anisotropy of nickel-base superalloy single crystals

The influence of orientation on the tensile and stress rupture behavior of 52 Mar-M247 single crystals was studied. Tensile tests were performed at temperatures between 23 and 1093 C; stress rupture behavior was examined between 760 and 1038 C. The mechanical behavior of the single crystals was rationalized on the basis of the Schmid factor contours for the operative slip systems and the lattice rotations which the crystals underwent during deformation. The tensile properties correlated well with the appropriate Schmid factor contours. The stress rupture lives at lower testing temperatures were greatly influenced by the lattice rotations required to produce cross slip. A unified analysis was attained for the stress rupture life data generated for the Mar-M247 single crystals at 760 and 774 C under a stress of 724 MPa and the data reported for Mar-M200 single crystals tested at 760 C under a stress of 689 MPa. Based on this analysis, the stereographic triangle was divided into several regions which were rank ordered according to stress rupture life for this temperature regime

Diffraction-limited CCD imaging with faint reference stars

By selecting short exposure images taken using a CCD with negligible readout noise we obtained essentially diffraction-limited 810 nm images of faint objects using nearby reference stars brighter than I=16 at a 2.56 m telescope. The FWHM of the isoplanatic patch for the technique is found to be 50 arcseconds, providing ~20% sky coverage around suitable reference stars.Comment: 4 page letter accepted for publication in Astronomy and Astrophysic

Comprehensive cosmographic analysis by Markov Chain Method

We study the possibility to extract model independent information about the dynamics of the universe by using Cosmography. We intend to explore it systematically, to learn about its limitations and its real possibilities. Here we are sticking to the series expansion approach on which Cosmography is based. We apply it to different data sets: Supernovae Type Ia (SNeIa), Hubble parameter extracted from differential galaxy ages, Gamma Ray Bursts (GRBs) and the Baryon Acoustic Oscillations (BAO) data. We go beyond past results in the literature extending the series expansion up to the fourth order in the scale factor, which implies the analysis of the deceleration, q_{0}, the jerk, j_{0} and the snap, s_{0}. We use the Markov Chain Monte Carlo Method (MCMC) to analyze the data statistically. We also try to relate direct results from Cosmography to dark energy (DE) dynamical models parameterized by the Chevalier-Polarski-Linder (CPL) model, extracting clues about the matter content and the dark energy parameters. The main results are: a) even if relying on a mathematical approximate assumption such as the scale factor series expansion in terms of time, cosmography can be extremely useful in assessing dynamical properties of the Universe; b) the deceleration parameter clearly confirms the present acceleration phase; c) the MCMC method can help giving narrower constraints in parameter estimation, in particular for higher order cosmographic parameters (the jerk and the snap), with respect to the literature; d) both the estimation of the jerk and the DE parameters, reflect the possibility of a deviation from the LCDM cosmological model.Comment: 24 pages, 7 figure

Survey evidence on the impact of lecture recording on equality, diversity and inclusion aims in higher education

In this study, 295 (13.8% response rate) first year students in a large, Scottish, Russell-Group university were surveyed on their attitudes to and use of lecture recordings in 2018. Kruskal-Wallis tests were used to compare ranked responses between students in different categories relevant to monitoring equality and diversity, such as carer status (5% of respondents), learning adjustments (9% of respondents) and non-native English speakers (27% of respondents). Students most commonly watched a full lecture by themselves when studying with 60% watching a full lecture at least once a week. Non-native English speakers were more likely to watch specific parts of a lecture more frequently (H(2) = 8.52, P = 0.014). Students with learning adjustments more often reported being unable to find a resource (H(3)=8.356, p = 0.039). There was no effect of students’ language, carer status or learning adjustment status on their self-reported likelihood to attend a lecture, likelihood to change note taking behaviour, or concentrate on a lecture if it was being recorded. Non-native English speakers were still more likely to worry about keeping up with a lecture, even when it was being recorded (H(2) = 10.492, p = 0.005). In conclusion, lecture recording has different impacts on students from different backgrounds, and inclusive lecture recording education policies need to consider this impact

A Renormalization Group for Hamiltonians: Numerical Results

We describe a renormalization group transformation that is related to the breakup of golden invariant tori in Hamiltonian systems with two degrees of freedom. This transformation applies to a large class of Hamiltonians, is conceptually simple, and allows for accurate numerical computations. In a numerical implementation, we find a nontrivial fixed point and determine the corresponding critical index and scaling. Our computed values for various universal constants are in good agreement with existing data for area-preserving maps. We also discuss the flow associated with the nontrivial fixed point.Comment: 11 Pages, 2 Figures. For future updates, check ftp://ftp.ma.utexas.edu/pub/papers/koch