1,271 research outputs found
Evolution of Compact Stars and Dark Dynamical Variables
This work is aimed to explore the dark dynamical effects of modified
gravity theory on the dynamics of compact celestial star. We have taken the
interior geometry as spherical star which is filled with imperfect fluid
distribution. The modified field equations are explored by taking a particular
form of model, i.e., . These equations are
then utilized to formulate the well-known structure scalars under the dark
dynamical effects of this higher order gravity theory. Also, the evolution
equations for expansion and shear are formulated with the help of these scalar
variables. Further, all this analysis have been made under the condition of
constant and . We found a crucial significance of dark source terms and
dynamical variables on the evolution and density inhomogeneity of compact
objects.Comment: 18 pages, 4 figures, version accepted for publication in European
Physical Journal
A holistic analysis method to assess the controllability of commercial buildings and their systems
This paper describes a novel design process for advanced MIMO (multiple inputs and multiple outputs) control system design and simulation for buildings. The paper describes the knowledge transfer from high technology disciplines such as aerospace flight control systems and the space industry to establish a three-step modelling and design process. In step 1, simplified, but holistic nonlinear and linearised dynamic models of the building and its systems is derived. This model is used to analyse the controllability of the building. In step 2, further synthesis of this model leads to the correct topology of the control system design. This is proved through the use of simulation using the simple building model. In step 3, the controller design is proved using a fully detailed building simulation such as ESP-r that acts as a type of virtual prototype of the building. The conclusions show that this design approach can help in the design of superior and more complex control systems especially for buildings designed with a Climate Adaptive Building (CAB) philosophy where many control inputs and outputs are used to control the building's temperature, concentration of CO2, humidity and lighting levels
Influence of Models on the Existence of Anisotropic Self-Gravitating Systems
This paper aims to explore some realistic configurations of anisotropic
spherical structures in the background of metric gravity, where is
the Ricci scalar. The solutions obtained by Krori and Barua are used to examine
the nature of particular compact stars with three different modified gravity
models. The behavior of material variables is analyzed through plots and the
physical viability of compact stars is investigated through energy conditions.
We also discuss the behavior of different forces, equation of state parameter,
measure of anisotropy and Tolman-Oppenheimer-Volkoff equation in the modeling
of stellar structures. The comparison from our graphical representations may
provide evidences for the realistic and viable gravity models at both
theoretical and astrophysical scale.Comment: 23 pages, 13 figures, version accepted for publication in European
Physical Journal
Influence of Electric Charge and Modified Gravity on Density Irregularities
This work aims to identify some inhomogeneity factors for plane symmetric
topology with anisotropic and dissipative fluid under the effects of both
electromagnetic field as well as Palatini gravity. We construct the
modified field equations, kinematical quantities and mass function to continue
our analysis. We have explored the dynamical quantities, conservation equations
and modified Ellis equations with the help of a viable model. Some
particular cases are discussed with and without dissipation to investigate the
corresponding inhomogeneity factors. For non-radiating scenario, we examine
such factors with dust, isotropic and anisotropic matter in the presence of
charge. For dissipative fluid, we investigate the inhomogeneity factor with
charged dust cloud. We conclude that electromagnetic field increases the
inhomogeneity in matter while the extra curvature terms make the system more
homogeneous with the evolution of time.Comment: 28 pages, no figure, version accepted for publication in European
Physical Journal
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