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Full-Text Articles in Physical Sciences and Mathematics
Some Rather Mechanical Reflections On Symmetry: In Art, Science, Engineering, Mathematics, Etc., Jim Mcgovern
Some Rather Mechanical Reflections On Symmetry: In Art, Science, Engineering, Mathematics, Etc., Jim Mcgovern
Articles
This Inaugural Lecture consists of some of my rather mechanical, being an engineer, reflections on symmetry in diverse areas such as art, science, engineering, mathematics, etc. I explain what symmetry is to me, giving examples with lots of images and mentioning or at least barely referencing art, science, architecture, engineering, heritage, cosmology, bicycles, flight, invention, ingenuity, history, wallpaper, mathematics, typography, structures, regular shapes, coordinate systems, spacetime, thermodynamics and suchlike.
The Transport Of Cosmic Rays In Self‐Excited Magnetic Turbulence, Brian Reville, Stephen O'Sullivan, Peter Duffy, John Kirk
The Transport Of Cosmic Rays In Self‐Excited Magnetic Turbulence, Brian Reville, Stephen O'Sullivan, Peter Duffy, John Kirk
Articles
The process of diffusive shock acceleration relies on the efficacy with which hydromagnetic waves can scatter charged particles in the precursor of a shock. The growth of self-generated waves is driven by both resonant and non-resonant processes. We perform high-resolution magnetohydrodynamic simulations of the non-resonant cosmic ray driven instability, in which the unstable waves are excited beyond the linear regime. In a snapshot of the resultant field, particle transport simulations are carried out. The use of a static snapshot of the field is reasonable given that the Larmor period for particles is typically very short relative to the instability growth …
Interacting Jets From Binary Protostars, Gareth Murphy, Thibaut Lery, Stephen O'Sullivan, Daniel S. Spicer, Francesca Bacciotti, Alex Rosen
Interacting Jets From Binary Protostars, Gareth Murphy, Thibaut Lery, Stephen O'Sullivan, Daniel S. Spicer, Francesca Bacciotti, Alex Rosen
Articles
Aims. We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and jets. However, binary jets have only been observed in a very small number of systems. Methods. We model numerically 3D binary jets for various outflow parameters. We also model the propagation of jets from a specific source, namely L1551 IRS 5, known to have two jets, using recent observations as constraints for simulations with a new MHD code. We examine their morphology and dynamics, and produce synthetic emission maps. Results. We find that the …
Equation Of State For A Van Der Waals Universe During Reissner–Nordstrom Expansion, Emil Prodanov, Rossen Ivanov, Vesselin Gueorguiev
Equation Of State For A Van Der Waals Universe During Reissner–Nordstrom Expansion, Emil Prodanov, Rossen Ivanov, Vesselin Gueorguiev
Articles
In a previous work [E.M. Prodanov, R.I. Ivanov and V.G. Gueorguiev, Reissner-Nordström expansion, Astropart. Phys. 27 (2007) 150], we proposed a classical model for the expansion of the Universe during the radiation-dominated epoch based on the gravitational repulsion of the Reissner-Nordström geometry — naked singularity description of particles that "grow" with the drop of the temperature. In this work we model the Universe during the Reissner-Nordström expansion as a van der Waals gas and determine the equation of state.