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Space Science International
Number of Followers: 140 Open Access journal ISSN (Print) 1948-9927 - ISSN (Online) 1948-9935 Published by Science Publications [31 journals] |
- An Integrated Approach to Modelling of Flood Hazards in the Rapidly
Growing City of Osogbo, Osun State, Nigeria
Abstract: In recent times, the swift and uncoordinated urban expansion in the medium sized city of Osogbo has increasingly encroached on the environmental sensitive areas. This uncoordinated exploitation of the ecological fragile areas for urban development has triggered urban flooding, which poses serious threat to human lives and properties in the city. This study therefore utilized geospatial technologies to generate flood hazard model for medium sized cities in developing countries in general and Nigeria in particular with a view to identifying hotspots and providing measures to forestall flood occurrences. The study used Shuttle Radar Topography Mission-Digital Elevation Model (SRTM-DEM), Landsat 7- 2000 and Operational Land Imager 8 (OLI)- 2015 images. Multi-criteria evaluation method was used to derive the physical characteristics of watersheds from the data to delineate the areas vulnerable to flooding. Flood inundation characteristics were simulated using Hydrologic Engineering Centre-River Analysis System (HEC-RAS) model with GIS interface and found discharge of over 500 m3/s for the 100-year profile period to be high, given the size of the analyzed basin (207.41 km2). The flood hazard map showed that 3.92, 103.38 and 100.11 km2 were least, moderately and highly vulnerable areas respectively. Most prone areas were built-ups with high impervious surface in the basin area where floodplain traversed high and moderate vulnerability zones. The study advocates consistent use of dynamic model within GIS for floodplain delineation and management planning to reduce the flood hazards.
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- The Cosmic Microwave Background: A Condition of Maximum
Abstract: It is shown that by imposing a condition of maximum value for the luminosity of the source at the origin of the cosmic microwave background, one arrives at a set of equations characteristic to important cosmological quantities. Although these equations do not have a solid theoretical support, the values of the parameters derived from them agree surprisingly well with the values given by the most recent measurements.
- On the Generation of Equivalent ‘Black Hole’ Metrics:
A Review
Abstract: Various line-elements purporting different types of blackhole universes have been advanced by cosmologists but a means by which therequired infinite set of equivalent metrics can be generated has evaded them.Without such a means the theory of black holes is not only incomplete but alsoill-posed. Notwithstanding, the mathematical form by which the infinite set ofequivalent metrics is generated was first revealed in 2005, from other quartersand it has in turn revealed significant properties of black hole universeswhich cosmology has not realised. The general metric ground-form from which theinfinite set of equivalent ‘black hole’ metrics can be generated is presentedherein and its consequences explored.
- Multi-Timescale Microscopic Theory for Radiation Degradation of Electronic
and Optoelectronic Devices
Abstract: A multi-timescale hybrid model is proposed to studymicroscopically the degraded performance of electronic devices, covering threeindividual stages of radiation effects studies, including ultra-fastdisplacement cascade, intermediate defect stabilization and cluster formation,as well as slow defect reaction and migration. Realistic interatomic potentialsare employed in molecular-dynamics calculations for the first two stages up to100 ns as well as for the system composed of layers with thicknesses ofhundreds of times the lattice constant. These quasi-steady-state results for individuallayers are input into a rate-diffusion theory as initial conditions tocalculate the steady-state distribution of point defects in a mesoscopic-scalelayered-structure system, including planar biased dislocation loops andspherical neutral voids, on a much longer time scale. Assisted by thedensity-functional theory for specifying electronic properties of pointdefects, the resulting spatial distributions of these defects and clusters aretaken into account in studying thedegradation of electronic and optoelectronic devices, e.g., carriermomentum-relaxation time, defect-mediated non-radiative recombination,defect-assisted tunneling of electrons and defect or charged-defect Ramanscattering as well. Such theoretical studies are expected to be crucial infully understanding the physical mechanism for identifying defect species,performance degradations in field-effect transistors, photo-detectors,light-emitting diodes and solar cells and in the development of effectivemitigation methods during their microscopic structure design stages.
- THREE FUNDAMENTAL MASSES DERIVED BY DIMENSIONAL ANALYSIS
Abstract: Three new mass dimension quantities have been derived by dimensional analysis, in addition to the famous Planck mass mP ~10-8 kg. These masses have been derived by means of fundamental constants-the speed of light (c), the gravitational constant (G), the Plank constant (?) and the Hubble constant (H). The enormous mass m1 ~1053 kg practically coincides with the Hoyle-Carvalho formula for the mass of the observable universe. The extremely small mass m2 ~10-33 eV has been identified with the minimum quantum of energy, which seems close to the graviton mass. It is noteworthy that the Planck mass appears geometric mean of the masses m1 and m2. The mass m3 ~107 GeV could not be unambiguously identified at present time. Besides, the order of magnitude of the total density of the universe has been estimated by this approach.
- EARLY GREEK ASTROPHYSICS: THE FOUNDATIONS OF MODERN SCIENCE AND TECHNOLOGY
Abstract: The foundations of modern science and technology, metrology, experimental physics, theoretical physics, theoretical mathematics, astrophysics, including applied optics and spectroscopy go back to the Prehistoric, Presocratic, Classical and Hellenistic Greece. This tradition is well deep rooted in time, going back mainly to the epoch of the prehistoric Aegean sea, the mainland of Greece and the Islands, Cycladic, Euboea, as well as Crete, at the late Neolithic period, probably starting back at 4400 BC. Humans observe the sky before the prehistoric era and wonder and as even Plato declares, these observations that lead us to try and understand the Cosmos make us humans as well, since the actual meaning and etymology of this term human in Greek, the word ANTHROPOS, is the one that looks up, observes the ordered Universe and tries to understand its nature and its hidden Laws which govern it. Science and Philosophy emerged as a result of the human efforts to live even more successfully within a hostile environment. Humanity eventually manages to understand Nature and especially the Cosmos, using the Pythagorean principle: “Nature can only be understood accurately by the use of Mathematics, which expresses the underlying Laws of Nature and which explain all natural phenomena based on the Principe of Causality.
- SPACE TIME COVARIANCE OF CANONICAL QUANTIZATION OF GRAVITY: A (FORMAL)
GENERAL RESULT AND THE (RIGOROUS) EXPLICIT CASE OF 2+1 QUANTUM COSMOLOGY
Abstract: A general classical theorem is presented according to which all invariant relations among the space time metric scalars, when turned into functions on the Phase Space of full Pure Gravity (using the Canonical Equations of motion), be-come weakly vanishing functions of the Quadratic and Linear Constraints. The implication of this result is that (formal) Dirac consistency of the Quantum Operator Constraints (annihilating the wave Function) suffices to guarantee space time covariance of the ensuing quantum theory: An ordering for each invariant relation will always exist such that the emanating operator has an eigenvalue identical to the classical value. The example of 2+1 Quantum Cosmology is explicitly considered: The four possible “Cosmological Solutions” -two for pure Einstein's equations plus two more when a ? term is present- are exhibited and the corresponding models are quantized. The invariant relations describing the geometries are explicitly calculated and promoted to operators whose eigenvalues are their corresponding classical values.
- NILPOTENCE AND THE GENERALIZED UNCERTAINTY PRINCIPLE (S)
Abstract: We point out that some of the proposed generalized/modified uncertainty principles originate from solvable, or nilpotent at appropriate limits, “deformations” of Lie algebras. We briefly comment on formal aspects related to the well-posedness of one of these algebras. We point out a potential relation of such algebras with Classical Mechanics in the spirit of the symplectic non-squeezing theorem. We also point out their relation to a hierarchy of generalized measure theories emerging in a covariant formalism of quantum gravity.
- DISCOVERY OF DYNAMICAL 3-SPACE: THEORY, EXPERIMENTS AND OBSERVATIONS-A
REVIEW
Abstract: The existence of space as a dynamical system was recently revealed in 2002, following the discovery that the Michelson-Morley light speed anisotropy experiment of 1887 was not null. Numerous later experiments have confirmed that discovery, as reviewed here, with the latest being the discovery of a very simple and cheap nanotechnology quantum detector method for observing space and its fluctuations/turbulence: Gravitational waves. As well over the last ten years the dynamical theory for space has been under development and has now been successfully tested against experiment and astronomical observations, explaining, in particular, the observed characteristics of galactic black holes, galactic rotations and universe expansion, all without “dark matter” and “dark energy”.
- NON-SINGULAR THERMODYNAMIC GRAVITY
Abstract: Newton formed his laws of motion, but still had to assume a law of gravity in order to determine the motions of bodies interacting through gravitational forces. Newton gave a prescription of how to find the dynamics produced by gravity. Einstein sought to determine the motions of gravity without using a force. Rather, he sought a system of equations by which the dynamics of bodies interacting through gravity were determined by the least distance between two points in a curved space. In both of these approaches gravity was basically independent of other forces of nature. Newton’s approach was to provide a system of equations that determined the motion of bodies interacting through forces in any choice of geometry. Einstein’s approach was to require that the force of gravity determine the geometry since he sought to find the motions without using a force. Newton gave three laws of motion in equations that could be used to find various types of energy such as potential energy or kinetic energy. This arrangement has the forces determining the energy of interactions. The approach presented here basically reverses these roles of energy and forces. It starts with a law stating the conservation of energy which states how any exchange of energy between a system and its surroundings affects the system’s energy and the work it can perform. It is a law stating how these three energies, exchange energy, system energy and work, can interact. The expression for work, force acting through a distance, must be a path dependent term which also makes the exchange energy path dependent. However, the system’s energy is not path dependent. The difference between the path dependence of the work and the path independence of the system’s energy is shown to be crucial to the law’s determination of dynamics.
- TUNNELING OF DIRAC PARTICLES FROM PHANTOM REISSNER NORDSTROM ANTI DE
SITTER BLACK HOLE
Abstract: We study the Hawking radiation of Dirac particles from RN ADS black hole through tunneling method. We use charge relativistic Dirac equation to study the emission of such particles. To solve Dirac equation we use WKB approximation and find the tunneling probability of outgoing particles. Finally we find the Hawking temperature for such type of black holes.