Smoothed particle magnetohydrodynamic simulations of protostellar outflows with misaligned magnetic field and rotation axes

We have developed a modified form of the equations of smoothed particle magnetohydrodynamics which are stable in the presence of very steep density gradients. Using this formalism, we have performed simulations of the collapse of magnetised molecular cloud cores to form protostars and drive outflows. Our stable formalism allows for smaller sink particles (< 5 AU) than used previously and the investigation of the effect of varying the angle, {\theta}, between the initial field axis and the rotation axis. The nature of the outflows depends strongly on this angle: jet-like outflows are not produced at all when {\theta} > 30{\deg}, and a collimated outflow is not sustained when {\theta} > 10{\deg}. No substantial outflows of any kind are produced when {\theta} > 60{\deg}. This may place constraints on the geometry of the magnetic field in molecular clouds where bipolar outflows are seen.Comment: Accepted for publication in MNRAS, 13 pages, 14 figures. Animations can be found at http://www.astro.ex.ac.uk/people/blewis/research/outflows_misaligned_fields.htm

Methodology development for evaluation of selective-fidelity rotorcraft simulation

This paper addressed the initial step toward the goal of establishing performance and handling qualities acceptance criteria for realtime rotorcraft simulators through a planned research effort to quantify the system capabilities of 'selective fidelity' simulators. Within this framework the simulator is then classified based on the required task. The simulator is evaluated by separating the various subsystems (visual, motion, etc.) and applying corresponding fidelity constants based on the specific task. This methodology not only provides an assessment technique, but also provides a technique to determine the required levels of subsystem fidelity for a specific task

NERVA irradiation program, GTR test 21. Volume 4 - Effect of radiation on structural materials tested at cryogenic and elevated temperatures

Effect of radiation on structural materials for NERVA engine tested at cryogenic and elevated temperatures - Vol.

Physiology and pathophysiology of excitation–contraction coupling in skeletal muscle: the functional role of ryanodine receptor

Calcium (Ca2+) release from intracellular stores plays a key role in the regulation of skeletal muscle contraction. The type 1 ryanodine receptors (RyR1) is the major Ca2+ release channel on the sarcoplasmic reticulum (SR) of myocytes in skeletal muscle and is required for excitation–contraction (E–C) coupling. This article explores the role of RyR1 in the skeletal muscle physiology and pathophysiology

Smoothed particle magnetohydrodynamic simulations of protostellar outflows with misaligned magnetic field and rotation axes (dataset)

The compressed tarballs in this repository contain the binary output data from the SPMHD (smoothed particle magnetohydrodynamics) simulation presented in the paper. The data is a Fortran binary file in big-endian format. The DAT???? files are dumps of the simulation spaced every 1/100 of a free-fall time and can be read in Splash (Written by Daniel Price, see http://users.monash.edu.au/~dprice/splash/). The Atest_? and Ptest_? files contain information on accreted particles and sink particles respectively (again in big-endian format). The two Fortran programs in utils.tar.xz can read these files and output ASCII data. The tarballs themselves are named according to the following scheme: theta_*.tar.xz are the 1.5 million particle simulations presented as the main result of the paper, where theta_0.tar.xz is a fully aligned model and theta_90.tar.xz is fully misaligned (i.e. theta = 90) &c.; lowres_*.tar.xz are the two low-resolution collapse simulations earlier in the paper and disc_*.tar.xz are the two test models. For both the low-resolution and test models, `clean' denotes the result of using and unmodified code and `hav' denotes the new formalism presented in the paper. All the plots in the paper, except for Figs. 13 and 14, can be produced using Splash and the `DAT' files directly. Figs. 13 and 14 use the data extracted from the `A' and `P' files.The journal article associated with this datast was published in Monthly Notices of the Royal Astronomical Society Vol. 451 (1), pp 288-299. doi: 10.1093/mnras/stv957 and is in ORE at http://hdl.handle.net/10871/19588The article associated with this dataset is available in ORE at http://hdl.handle.net/10871/19588.This is the dataset that was used to produce the paper published in MNRAS. Included are the binary dump files from each of the simulations in the paper and two utilities that can be used to produce an ASCII file detailing accreted particles.Science and Technology Facilities CouncilEuropean Research CouncilAustralian Research Council Discovery Project GrantUniversity of Exeter Supercomputer: jointly funded by Science and Technology Facilities Council (STFC), Large Facilities Capital Fund of BIS, and the University of Exeter DiRac Complexity computer: jointly funded by Science and Technology Facilities Council (STFC) and the Large Facilities Capital Fund of BI

Supersonic Crossflow Transition Control in Ground and Flight Tests

This paper describes the use of distributed-roughness-element (DRE) patterns along a Mach 2 design swept-wing leading edge to increase the laminar flow extent and thereby reduce drag. One swept-wing model was tested in a supersonic wind tunnel as well as beneath a supersonic flight vehicle. Wing model surface data acquired during these tests included pressures, temperatures, and boundary-layer transition locations. Similarities and differences in experimental results are discussed. While wind tunnel and flight results show some differences, the wind tunnel results still provide key insights necessary for understanding how to design effective DRE patterns for use in flight applications. Experimental results demonstrate a DRE flow control effect observed in flight similar to that observed in the wind tunnel. Finally, a different perspective is discussed concerning what flow control role RE patterns might perform in any future swept-wing laminar flow control applications

AtomSim: web-deployed atomistic dynamics simulator

AtomSim, a collection of interfaces for computational crystallography simulations, has been developed. It uses forcefield-based dynamics through physics engines such as the General Utility Lattice Program, and can be integrated into larger computational frameworks such as the Virtual Neutron Facility for processing its dynamics into scattering functions, dynamical functions etc. It is also available as a Google App Engine-hosted web-deployed interface. Examples of a quartz molecular dynamics run and a hafnium dioxide phonon calculation are presented