3,698 research outputs found
Thermal Behaviour of Euclidean Stars
A recent study of dissipative collapse considered a contracting sphere in
which the areal and proper radii are equal throughout its evolution. The
interior spacetime was matched to the exterior Vaidya spacetime which generated
a temporal evolution equation at the boundary of the collapsing sphere. We
present a solution of the boundary condition which allows the study of the
gravitational and thermodynamical behaviour of this particular radiating model.Comment: 10 pages, 3 figure
A family of charged compact objects with anisotropic pressure
Utilizing an ansatz developed by Maurya and co-workers we present a class of
exact solutions of the Einstein-Maxwell field equations describing a
spherically symmetric compact object. A detailed physical analysis of these
solutions in terms of stability, compactness and regularity indicate that these
solutions may be used to model strange star candidates. In particular, we model
the strange star candidate Her X-1 and show that our solution conforms to
observational data to an excellent degree of accuracy. An interesting and novel
phenomenon which arises in this model is the fact that the relative difference
between the electromagnetic force and the force due to pressure anisotropy
changes sign within the stellar interior. This may be a an additional mechanism
required for stability against cracking of the stellar object
Radiating Collapse with Vanishing Weyl stresses
In a recent approach in modelling a radiating relativistic star undergoing
gravitational collapse the role of the Weyl stresses was emphasised. It is
possible to generate a model which is physically reasonable by approximately
solving the junction conditions at the boundary of the star. In this paper we
demonstrate that it is possible to solve the Einstein field equations and the
junction conditions exactly. This exact solution contains the Friedmann dust
solution as a limiting case. We briefly consider the radiative transfer within
the framework of extended irreversible thermodynamics and show that
relaxational effects significantly alter the temperature profiles.Comment: 10 pages, submitted to IJMP-
The role of shear in dissipative gravitational collapse
In this paper we investigate the physics of a radiating star undergoing
dissipative collapse in the form of a radial heat flux. Our treatment clearly
demonstrates how the presence of shear affects the collapse process; we are in
a position to contrast the physical features of the collapsing sphere in the
presence of shear with the shear-free case. By employing a causal heat
transport equation of the Maxwell-Cattaneo form we show that the shear leads to
an enhancement of the core temperature thus emphasizing that relaxational
effects cannot be ignored when the star leaves hydrostatic equilibrium.Comment: 15 pages, To appear in Int. J. Mod. Phys.
The impact of general education in enhancing the self-efficacy of accounting students at universities of technology
The aim of this article is to investigate the integration of General Education in improving the Self-efficacy of Cost and Management Accounting (CMA) students to assess whether Self-efficacy, is having any positive impact on the students’ academic performance. The research design of this article was descriptive, longitudinal and employed a mixed-method approach. The nature of the quasi-experimental approach that was used in the current article is a non-equivalent pre-test and post-test control group design. The target population was CMA students. A census survey was performed. Findings, which were analysed with the aid of descriptive statistics, indicate a significant correlation in the post-test (Self-efficacy) scores of the group that undertook the General Education Modules and not the group that did not undertake the General Education Modules. This article recommends the implementation of General Education skills into the curriculum and a General Education intervention strategy. Moreover, these skills appear to be very poor amongst current learners and respondents believed that Self-efficacy could have a positive effect on the academic performance of learners.
 
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