16 research outputs found
Magnetic Moments of Heavy Baryons Using Effective Mass and Screened Charge Scheme
Magnetic moments of heavy charmed baryons with are predicted
employing the concept of effective quark mass and screened charge of quark. We
also extend our scheme to predict the transition magnetic
moments. A comparison of our results with the predictions obtained in recent
models is presented.Comment: 19 pages, Accepted for publication in EPJ-
Theory of magnetically powered jets
The magnetic theory for the production of jets by accreting objects is
reviewed with emphasis on outstanding problem areas. An effort is made to show
the connections behind the occasionally diverging nomenclature in the
literature, to contrast the different points of view about basic mechanisms,
and to highlight concepts for interpreting the results of numerical
simulations. The role of dissipation of magnetic energy in accelerating the
flow is discussed, and its importance for explaining high Lorentz factors. The
collimation of jets to the observed narrow angles is discussed, including a
critical discussion of the role of `hoop stress'. The transition between disk
and outflow is one of the least understood parts of the magnetic theory; its
role in setting the mass flux in the wind, in possible modulations of the mass
flux, and the uncertainties in treating it realistically are discussed. Current
views on most of these problems are still strongly influenced by the
restriction to 2 dimensions (axisymmetry) in previous analytical and numerical
work; 3-D effects likely to be important are suggested. An interesting problem
area is the nature and origin of the strong, preferably highly ordered magnetic
fields known to work best for jet production. The observational evidence for
such fields and their behavior in numerical simulations is discussed. I argue
that the presence or absence of such fields may well be the `second parameter'
governing not only the presence of jets but also the X-ray spectra and timing
behavior of X-ray binaries.Comment: 29 pages. Publication delays offered the opportunity for further
corrections, an expansion of sect 4.2, and one more Fig. To appear in
Belloni, T. (ed.): The Jet Paradigm - From Microquasars to Quasars, Lect.
Notes Phys. 794 (2009
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
Mechanisms of drying of particulate slurries
The literature on the evaporation of pure liquid drops and the drying of drops of solutions and slurries has been reviewed with particular reference to spray drying. A 0.1-0.2 mm glass filament-thermocouple was constructed and used to study simultaneously, heat and mass transfer from a single suspended drop placed in a humidity and temperature controlled, 28 mm OD vertical wind tunnel. Heat conduction through the filament was minimised eg at 100¦C it accounted for only 9.3% of the total heat transferred to a drop. Evaporation of single water drops was also studied in a 101 mm OD vertical wind tunnel. The Nusselt number was found to be a function of the Reynolds, Prandtl and Transfer number over an air temperature range of 17¦C to 107¦C. The proposed correlation is: Nu = 2+(-12.96B+0.76)Re¦-5Pr0-33 Experimental drying studies were carried out on single suspended 1 to 2.5 mm diameter drops of aqueous sodium sulphate decahydrate, sodium chloride, potassium sulphate, copper sulphate and sodium acetate solutions and slurries at temperatures of 20¦C to 124¦C. Dried crusts were examined by Scanning Electron Microscopy. The drying history of any material depended upon the nature of the crust formed. Sodium acetate formed a non-rigid skin prior to the formation of a rigid crust. A modified receding evaporation interface model was proposed for the drying of solutions and slurries. This covered both the constant rate period prior to crust formation and the subsequent falling rate period. The model was solved numerically for the variation in core temperature, drop weight and crust thickness. Good agreement was obtained between model predictions and experimental results for materials forming rigid crusts i.e. sodium sulphate decahydrate, sodium chloride, potassium sulphate and copper sulphate. However, the drying histories of drops of 10-20% weight initial concentration sodium acetate were unpredictable since formation of a non-rigid skin deviated from the model assumption of a rigid outer surface. At higher initial concentrations (40% weight) where a rigid crust was formed for sodium acetate, good agreement was obtained between experimental results and model predictions. Single suspended drop studies are concluded to provide a valuable insight into the drying mechanisms of specific solutions and slurries
The influence of control motivation on social cognition
SIGLEAvailable from British Library Lending Division - LD:D54966/85 / BLDSC - British Library Document Supply CentreGBUnited Kingdo