35,378 research outputs found
Enhanced Stability of Superheavy Nuclei due to High-Spin Isomerism
Configuration-constrained calculations of potential-energy surfaces in
even-even superheavy nuclei reveal systematically the existence at low
excitation energies of multi-quasiparticle states with deformed axially
symmetric shapes and large angular momenta. These results indicate the
prevalence of long-lived, multi-quasiparticle isomers. In a quantal system, the
ground state is usually more stable than the excited states. In contrast, in
superheavy nuclei the multi-qausiparticle excitations decrease the probability
for both fission and decay, implying enhanced stability. Hence, the
systematic occurrence of multi-qausiparticle isomers may become crucial for
future production and study of even heavier nuclei. The energies of
multi-quasiparticle states and their decays are calculated and
compared to available data.Comment: 4 pages, 5 figures, accepted for publication in PR
Fundamentals of the small steelworks
The Development during the last twenty years of continuous casting, the extension of the use of the electric furnace into tonnage steel manufacture, and the ever increasing use of oxygen steelmaking techniques have all contributed towards making economically possible the installation of small steelworks
Tuning grid storage resources for LHC data analysis
Grid Storage Resource Management (SRM) and local file-system solutions are facing significant challenges to support efficient analysis of the data now being produced at the Large Hadron Collider (LHC). We compare the performance of different storage technologies at UK grid sites examining the effects of tuning and recent improvements in the I/O patterns of experiment software. Results are presented for both live production systems and technologies not currently in widespread use. Performance is studied using tests, including real LHC data analysis, which can be used to aid sites in deploying or optimising their storage configuration
Evaluation of a Brazilian fuel alcohol yeast strain for Scotch whisky fermentations
Traditionally, distilling companies in Scotland have employed a very limited number of yeast strains in the production of alcohol for Scotch whiskies. Recent changes such as the decline in availability of brewers’ yeast as a secondary yeast strain and the availability of yeast in different formats (e.g., dried and cream yeast as alternatives to compressed yeast) have promoted interest in alternative Scotch whisky distilling yeasts. In previous work, we investigated different strains of yeasts, specifically Brazilian yeasts which had been isolated from and used in fuel alcohol distilleries. One of the Brazilian yeasts (CAT 1) showed a comparable fermentation performance and superior stress tolerance compared with a standard commercial Scotch whisky distilling yeast (M Type). The Brazilian CAT 1 yeast isolate was further assessed in laboratory scale fermentations and subsequent new make spirit was subjected to sensory analyses. The spirits produced using the Brazilian strain had acceptable flavour profiles and exhibited no sensory characteristics that were atypical of Scotch whisky new make spirit. This study highlights the potential of exploiting yeast biodiversity in traditional Scotch whisky distillery fermentation processes
On Kinematic Substructure in the Sextans Dwarf Spheroidal Galaxy
We present multifiber echelle radial velocity results for 551 stars in the
Sextans dwarf spheroidal galaxy and identify 294 stars as probable Sextans
members. The projected velocity dispersion profile of the binned data remains
flat to a maximum angular radius of . We introduce a nonparametric
technique for estimating the projected velocity dispersion surface, and use
this to search for kinematic substructure. Our data do not confirm previous
reports of a kinematically distinct stellar population at the Sextans center.
Instead we detect a region near the Sextans core radius that is kinematically
colder than the overall Sextans sample with 95% confidence.Comment: accepted for publication in ApJ Letters; 4 figures (2 color
Report from solar physics
A discussion of the nature of solar physics is followed by a brief review of recent advances in the field. These advances include: the first direct experimental confirmation of the central role played by thermonuclear processes in stars; the discovery that the 5-minute oscillations of the Sun are a global seismic phenomenon that can be used as a probe of the structure and dynamical behavior of the solar interior; the discovery that the solar magnetic field is subdivided into individual flux tubes with field strength exceeding 1000 gauss. Also covered was a science strategy for pure solar physics. Brief discussions are given of solar-terrestrial physics, solar/stellar relationships, and suggested space missions
A theoretical review of the operation of vibratory stress relief with particular reference to the stabilization of large-scale fabrications
Vibratory stress relief (VSR) is widely used on large welded fabrications to stabilize the structures so that they do not distort during further machining or during operational duty. The level of applied stress achieved during VSR on such structures is only 5–10 per cent of the yield stress. It is, therefore, not obvious how these applied loads come to modify the level of residual stress. It is suggested here that the reason for the success of VSR applied to large fabrications lies (a) in the origin of the residual stresses and (b) in the partial relief of these residual stresses by the initiation of the transformation of retained austenite particles (in the size range from 1 to 25 µm) by the movement of dislocations into positions that are favourable for the nucleation of martensite embryos. The shear deformation associated with the transformation of retained austenite into martensite will reduce the residual stress field to the point where the stability of the structure may be assured
ALTERATION OF PACEMAKER THRESHOLD BY DRUG AND PHYSIOLOGICAL FACTORS
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73776/1/j.1749-6632.1969.tb34129.x.pd
Conformal smectics and their many metrics
We establish that equally spaced smectic configurations enjoy an infinite-dimensional conformal symmetry and show that there is a natural map between them and null hypersurfaces in maximally symmetric spacetimes. By choosing the appropriate conformal factor it is possible to restore additional symmetries of focal structures only found before for smectics on flat substrates
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