2,971 research outputs found
Calculation of mean and fluctuating properties of the incompressible turbulent boundary layer
Mathematical model for calculation of mean and fluctuating properties of incompressible turbulent boundary layer
Alien Registration- Beckwith, Ida M. (Gardiner, Kennebec County)
https://digitalmaine.com/alien_docs/29101/thumbnail.jp
Free radical 5-exo-dig cyclization as the key step in the synthesis of bis-butyrolactone natural products: experimental and theoretical studies
Radical cyclization reactions were performed by 5-exo-dig mode to yield cis-fused bicyclic systems, leading to the synthesis of bis-butyrolactone class of natural products. The study was aimed at understanding the impact of alkyl side chains of furanoside ring systems in L-ara configuration on the radical cyclization. It was amply demonstrated by experimental studies that the increase in the length of the alkyl side chain has an effect on the cyclization: while efficient cyclization reactions could be realized with methyl and ethyl side chains, the yields were significantly reduced in the case of n-pentyl side chain. Theoretical studies using DFT and (RO)MP2 methods were carried out to analyze the influence of the substitution pattern on the cyclization barriers
Computer program for compressible laminar or turbulent nonsimilar boundary layers
Description of computer program for solving two dimensional and axisymmetric forms of compressible boundary layer equations for continuity, mean momentum, and mean total enthalp
From Protein Folding to Blood Coagulation: Menaquinone as a Metabolic Link between Bacteria and Mammals
Menaquinones have long played a central role in bacterial metabolism due to their solubility in membranes and their ability to mediate electron transfer reactions between a large variety of enzymes. In addition to acting as important nodes in fermentation and respiration, menaquinones are critical to the formation of disulphide bonds in the periplasm. Their utility as molecular wires has also led to their incorporation into redox reactions in higher‐order organisms, where they participate in numerous physiological processes, including blood coagulation. Through studying the menaquinone‐dependent pathways in organisms across the phylogenetic spectrum, researchers have begun to uncover intriguing metabolic links and have identified novel compounds for modulating these vital pathways
A Second Order Godunov Method for Multidimensional Relativistic Magnetohydrodynamics
We describe a new Godunov algorithm for relativistic magnetohydrodynamics
(RMHD) that combines a simple, unsplit second order accurate integrator with
the constrained transport (CT) method for enforcing the solenoidal constraint
on the magnetic field. A variety of approximate Riemann solvers are implemented
to compute the fluxes of the conserved variables. The methods are tested with a
comprehensive suite of multidimensional problems. These tests have helped us
develop a hierarchy of correction steps that are applied when the integration
algorithm predicts unphysical states due to errors in the fluxes, or errors in
the inversion between conserved and primitive variables. Although used
exceedingly rarely, these corrections dramatically improve the stability of the
algorithm. We present preliminary results from the application of these
algorithms to two problems in RMHD: the propagation of supersonic magnetized
jets, and the amplification of magnetic field by turbulence driven by the
relativistic Kelvin-Helmholtz instability (KHI). Both of these applications
reveal important differences between the results computed with Riemann solvers
that adopt different approximations for the fluxes. For example, we show that
use of Riemann solvers which include both contact and rotational
discontinuities can increase the strength of the magnetic field within the
cocoon by a factor of ten in simulations of RMHD jets, and can increase the
spectral resolution of three-dimensional RMHD turbulence driven by the KHI by a
factor of 2. This increase in accuracy far outweighs the associated increase in
computational cost. Our RMHD scheme is publicly available as part of the Athena
code.Comment: 75 pages, 28 figures, accepted for publication in ApJS. Version with
high resolution figures available from
http://jila.colorado.edu/~krb3u/Athena_SR/rmhd_method_paper.pd
Why do people choose nephrology? Identifying positive motivators to aid recruitment and retention
Increasing concerns about recruitment and retention of junior doctors have led to renewed interest in how and when trainees choose their specialties. To our knowledge, no study has yet reported what attracts UK applicants to nephrology nor how clinicians develop vocational interests or make occupational choices. With this in mind, we sought to explore the motivation behind current nephrologist's career choices in the UK. We interviewed 11 nephrologists using a semi-structured face-to-face approach and used interpretative phenomenological analysis to conduct and analyse the interviews. We found role models were pivotal in encouraging specialization in nephrology, particularly those encountered in early postgraduate training. The diversity, diagnostic challenge and cross-specialty knowledge was highlighted as well as the ability to 'make a difference to patients' lives'. Nephrologists enjoyed the challenge of managing very sick, acutely unwell patients as well as the holistic continuity of long-term care offered to dialysis patients and their families. Academic and procedural components were attractive motivators to the specialty and the flexibility to have multiple interests was noted, with many nephrologists having 'portfolio' careers. Based on these results, we suggest strategies the specialty can use to aid policy decision making, promote recruitment and improve educational experiences within current training programmes
Free-stream noise and transition measurements on a cone in a Mach 3.5 pilot low-disturbance tunnel
A small scale Mach 3.5 wind tunnel incorporating certain novel design features and intended for boundary-layer-transition research has been tested. The free stream noise intensities and spectral distributions were determined throughout the test section for several values of unit Reynolds number and for nozzle boundary layer bleed on and off. The boundary layer transition location on a slender cone and the response of this to changes in the noise environment were determined. Root mean square free stream noise levels ranged from less than one tenth up to values approaching those for conventional nozzles, with the lowest values prevailing at upstream locations within the nozzle. For low noise conditions, cone transition Reynolds numbers were in the range of those for free flight; whereas for high noise conditions, they were in the range of those in conventional tunnels
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