The surface polaritons (SP) variation in Ga As/ Al Ga As/ LH hetrojunction composition in the presence of
a strong transverse quantized magnetic field is estimated using the quantum Hall effect case. The
dispersion characteristics of the SPs are investigated using the dielectric constants values of the Ga As and
the Alx Ga 1-x As media and the defined thickness, the Alx Ga 1-x As medium. The dispersion behaviours
calculated results are listed for considered cases. It was shown that the frequency values against the wave
vector values are affected in a strong manner by changing thickness, of the Alx
Ga 1-x- As media and by
changing the variation of the dielectric constants of Ga As against the Alx Ga 1-x As. The significance
effects of the use of the left-handed (LH) medium as an upper layer of the proposed composition was
demonstrated; the frequency values are remarkably increased using LH material as an upper layer. It was
noticed that at certain conditions of the LH upper layer composition, similar results have been obtained
such as found by using dielectric upper layer.
SURFACE POLARITONS IN GAAS/ALGAAS/LH HETROJUNCTION STRUCTURE IN A HIGH MAGNET...ijrap
This document summarizes research on surface polaritons in a GaAs/AlGaAs heterojunction structure with a left-handed material upper layer in a high magnetic field. The dispersion characteristics of surface polaritons are investigated using dielectric constants of GaAs and AlGaAs layers and a defined AlGaAs thickness. Electromagnetic waves are derived for the structure considering transverse magnetic and electric waves. Boundary conditions at layer interfaces and a surface current lead to a dispersion equation relating frequency, wave vector, conductivity, and layer properties. Calculated dispersion curves show frequency increases significantly when a left-handed upper layer is used compared to a dielectric layer.
Some Notes on Self-similar Axisymmetric Force-free Magnetic Fields and Rotati...Premier Publishers
An axisymmetric force-free magnetic field in spherical coordinates has a relationship between its azimuthal component to its poloidal flux-function. A power law dependence for the connection admits separable field solutions but poses a nonlinear eigenvalue boundary-value problem for the separation parameter (Low and Lou, Astrophys. J. 352, 343 (1990)).When the atmosphere of a star is rotating the problem complexity increases. These Notes consider the nonlinear eigenvalue spectrum, providing an understanding of the eigen functions and relationship between the field's degree of multi-polarity, the rotation and rate of radial decay as illustrated through a polytropic equation of state. The Notes are restricted to uniform rotation and to axisymmetric fields. Dominant effects are presented of rotation in changing the spatial patterns of the magnetic field from those without rotation. For differential rotation and non-axisymmetric force-free fields there may be field solutions of even richer topological structure but the governing equations have remained intractable to date. Perhaps the methods and discussion given here for the uniformly rotating situation indicate a possible procedure for such problems that need to be solved urgently for a more complete understanding of force-free magnetic fields in stellar atmospheres.
Exact Analytical Expression for Outgoing Intensity from the Top of the Atmosp...IOSR Journals
This research is a part of the work devoted on the application of analytical Discrete Ordinate (ADO) method to the polarized monochromatic radiative transfer equation undergoing anisotropic scattering with source function matrix in a finite coupled Atmosphere –Ocean media having flat interface boundary conditions involving specular reflection and transmission matrix. Discontinuities in the derivatives of the Stokes vector with respect to the cosine of the polar angle at smooth interface between the two media with different refractive indices (air and water) is tackled by using a suitable quadrature scheme devised earlier. Atmosphere and ocean are assumed to be homogeneous. No stratification is adopted in the two media. Exact expression for the
emergent radiation intensity vector from the top of the atmosphere is derived. Exact expressions for the emergent polarized radiation intensity vector from the air-water interface as well as from any point of the two medium in any direction can also be derived in terms of eigenvectors and eigenvalues.
This document presents a statistical theory of the equilibrium elastic and thermal properties of crystals that have rotational degrees of freedom. Microscopic expressions are derived for strain and stress tensors using a local equilibrium ensemble. Statistical expressions are obtained for properties like specific heat of deformed medium at fixed strain, elastic moduli, temperature stress coefficients, and coefficients of thermal expansion. These properties are described by static correlation functions of dynamical quantities related to strain tensors. The local equilibrium distribution approach allows consistent accounting of spatial dispersion of elastic and thermal properties in inhomogeneous asymmetric media.
The Equation Based on the Rotational and Orbital Motion of the PlanetsIJERA Editor
Equations of dependence of rotational and orbital motions of planets are given, their rotation angles are calculated. Wave principles of direct and reverse rotation of planets are established. The established dependencies are demonstrated at different scale levels of structural interactions, in biosystems as well. The accuracy of calculations corresponds to the accuracy of experimental data
CLASSICAL AND QUASI-CLASSICAL CONSIDERATION OF CHARGED PARTICLES IN COULOMB F...ijrap
On the basis of the theory of bound charges the calculation of the motion of the charged particle at the
Coulomb field formed with the spherical source of bound charges is carried out. Such motion is possible in
the Riemanniam space-time. The comparison with the general relativity theory (GRT) and special relativity
theory (SRT) results in the Schwarzshil'd field when the particle falls on the Schwarzshil'd and Coulomb
centres is carried out. It is shown that the proton and electron can to create a stable connection with the
dimensions of the order of the classic electron radius. The perihelion shift of the electron orbit in the
proton field is calculated. This shift is five times greater than in SRT and when corrsponding substitution of
the constants it is 5/6 from GRT. By means of the quantization of adiabatic invariants in accordance with
the method closed to the Bohr and Sommerfeld one without the Dirac equation the addition to the energy
for the fine level splitting is obtained. It is shown that the Caplan's stable orbits in the hydrogen atom
coincide with the Born orbits.
MAGNETOSTATIC SURFACE WAVES IN A LEFT HANDED / FERRITE/ METAL-STRIP-GRATING S...ijrap
The dispersion characteristics for magnetostatic surface waves in a left handed ( LHM)/ferrite/ metal-stripgrating
structure have been investigated. We found that, the waveguide supports backward TE waves
since both permittivity and magnetic permeability of LHM are negative. We also illustrated the
dependence of wave frequency on the reduced wave number for a grating shielding parameter, g values
restricted by the range 0 ≤ g ≥ 1. It is shown that the grating shielding parameter, g induces
magnetostatic backward shorter waves . The leakage through the grating increases with the wave number. The shorter backward magnetostatic waves are guided by the thicker waveguide where the best confinement is achieved
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
SURFACE POLARITONS IN GAAS/ALGAAS/LH HETROJUNCTION STRUCTURE IN A HIGH MAGNET...ijrap
This document summarizes research on surface polaritons in a GaAs/AlGaAs heterojunction structure with a left-handed material upper layer in a high magnetic field. The dispersion characteristics of surface polaritons are investigated using dielectric constants of GaAs and AlGaAs layers and a defined AlGaAs thickness. Electromagnetic waves are derived for the structure considering transverse magnetic and electric waves. Boundary conditions at layer interfaces and a surface current lead to a dispersion equation relating frequency, wave vector, conductivity, and layer properties. Calculated dispersion curves show frequency increases significantly when a left-handed upper layer is used compared to a dielectric layer.
Some Notes on Self-similar Axisymmetric Force-free Magnetic Fields and Rotati...Premier Publishers
An axisymmetric force-free magnetic field in spherical coordinates has a relationship between its azimuthal component to its poloidal flux-function. A power law dependence for the connection admits separable field solutions but poses a nonlinear eigenvalue boundary-value problem for the separation parameter (Low and Lou, Astrophys. J. 352, 343 (1990)).When the atmosphere of a star is rotating the problem complexity increases. These Notes consider the nonlinear eigenvalue spectrum, providing an understanding of the eigen functions and relationship between the field's degree of multi-polarity, the rotation and rate of radial decay as illustrated through a polytropic equation of state. The Notes are restricted to uniform rotation and to axisymmetric fields. Dominant effects are presented of rotation in changing the spatial patterns of the magnetic field from those without rotation. For differential rotation and non-axisymmetric force-free fields there may be field solutions of even richer topological structure but the governing equations have remained intractable to date. Perhaps the methods and discussion given here for the uniformly rotating situation indicate a possible procedure for such problems that need to be solved urgently for a more complete understanding of force-free magnetic fields in stellar atmospheres.
Exact Analytical Expression for Outgoing Intensity from the Top of the Atmosp...IOSR Journals
This research is a part of the work devoted on the application of analytical Discrete Ordinate (ADO) method to the polarized monochromatic radiative transfer equation undergoing anisotropic scattering with source function matrix in a finite coupled Atmosphere –Ocean media having flat interface boundary conditions involving specular reflection and transmission matrix. Discontinuities in the derivatives of the Stokes vector with respect to the cosine of the polar angle at smooth interface between the two media with different refractive indices (air and water) is tackled by using a suitable quadrature scheme devised earlier. Atmosphere and ocean are assumed to be homogeneous. No stratification is adopted in the two media. Exact expression for the
emergent radiation intensity vector from the top of the atmosphere is derived. Exact expressions for the emergent polarized radiation intensity vector from the air-water interface as well as from any point of the two medium in any direction can also be derived in terms of eigenvectors and eigenvalues.
This document presents a statistical theory of the equilibrium elastic and thermal properties of crystals that have rotational degrees of freedom. Microscopic expressions are derived for strain and stress tensors using a local equilibrium ensemble. Statistical expressions are obtained for properties like specific heat of deformed medium at fixed strain, elastic moduli, temperature stress coefficients, and coefficients of thermal expansion. These properties are described by static correlation functions of dynamical quantities related to strain tensors. The local equilibrium distribution approach allows consistent accounting of spatial dispersion of elastic and thermal properties in inhomogeneous asymmetric media.
The Equation Based on the Rotational and Orbital Motion of the PlanetsIJERA Editor
Equations of dependence of rotational and orbital motions of planets are given, their rotation angles are calculated. Wave principles of direct and reverse rotation of planets are established. The established dependencies are demonstrated at different scale levels of structural interactions, in biosystems as well. The accuracy of calculations corresponds to the accuracy of experimental data
CLASSICAL AND QUASI-CLASSICAL CONSIDERATION OF CHARGED PARTICLES IN COULOMB F...ijrap
On the basis of the theory of bound charges the calculation of the motion of the charged particle at the
Coulomb field formed with the spherical source of bound charges is carried out. Such motion is possible in
the Riemanniam space-time. The comparison with the general relativity theory (GRT) and special relativity
theory (SRT) results in the Schwarzshil'd field when the particle falls on the Schwarzshil'd and Coulomb
centres is carried out. It is shown that the proton and electron can to create a stable connection with the
dimensions of the order of the classic electron radius. The perihelion shift of the electron orbit in the
proton field is calculated. This shift is five times greater than in SRT and when corrsponding substitution of
the constants it is 5/6 from GRT. By means of the quantization of adiabatic invariants in accordance with
the method closed to the Bohr and Sommerfeld one without the Dirac equation the addition to the energy
for the fine level splitting is obtained. It is shown that the Caplan's stable orbits in the hydrogen atom
coincide with the Born orbits.
MAGNETOSTATIC SURFACE WAVES IN A LEFT HANDED / FERRITE/ METAL-STRIP-GRATING S...ijrap
The dispersion characteristics for magnetostatic surface waves in a left handed ( LHM)/ferrite/ metal-stripgrating
structure have been investigated. We found that, the waveguide supports backward TE waves
since both permittivity and magnetic permeability of LHM are negative. We also illustrated the
dependence of wave frequency on the reduced wave number for a grating shielding parameter, g values
restricted by the range 0 ≤ g ≥ 1. It is shown that the grating shielding parameter, g induces
magnetostatic backward shorter waves . The leakage through the grating increases with the wave number. The shorter backward magnetostatic waves are guided by the thicker waveguide where the best confinement is achieved
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
1) The paper investigates whether quantum variations around geodesics could circumvent caustics that occur in certain space-times.
2) An action is developed that yields both the field equations and geodesic condition. Quantizing this action provides a way to determine the extent of the wave packet around the classical path.
3) It is shown that replacing plane wave solutions with wave packets in the path integral still yields acceptable results. Determining if the distribution matches expectation values and variances is key to establishing geodesic completeness with quantum variations.
This document discusses the hydrodynamic equations that describe neutral gas and plasma, and how they are modified to become the magnetohydrodynamic (MHD) equations when a conducting fluid is in a magnetic field. It introduces the continuity, momentum, and entropy equations for neutral gas hydrodynamics. It then explains how these are updated to the MHD equations by adding magnetic forces and Ohm's law relating current and fields. The key MHD equations derived include equations for momentum, entropy, and the magnetic field evolving due to motion and diffusion.
Research Inventy : International Journal of Engineering and Scienceresearchinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
This document summarizes research on weak elastic anisotropy in geological materials. It finds that while most rocks exhibit some anisotropy, the anisotropy is often weak, defined as less than 20%. In cases of weak anisotropy, the equations governing wave propagation simplify significantly. Specifically, a parameter called delta (δ) emerges as the most important measure of anisotropy, rather than differences in vertical and horizontal velocities. The parameter δ does not involve horizontal velocity and may be positive or negative. Using δ, the document analyzes how weak anisotropy affects seismic exploration techniques like reflection profiling, even when the anisotropy is small.
EVALUATING STRUCTURAL, OPTICAL & ELECTRICAL CHARACTERIZATION OF ZINC CHALCOGE...Editor IJCATR
To evaluate the structural, optical & electrical properties of the zinc chalcogenides (ZnO, ZnS, ZnSe & ZnTe), the Full
Potential Linearized – Augumented Plane Wave plus Local Orbits (FP – LAPW+lo) method. For the purpose of exchange-correlation
energy (Exc) determination in Kohn–Sham calculation, the standard local density approximation (LDA) formalism has been utilized.
Murnaghan’s equation of state (EOS) has been used for volume optimization by minimizing the total energy with respect to the unit
cell volume. With the result of electronic density of states (DOS), the structural, optical and electrical properties of Zinc chalcogenides
have been calculated. The second derivative of energy, as a function of lattice strain has been successfully used to estimate the elastic
constants of these binary compounds. The results are in good agreement with other theoretical calculations as well as available
experimental data.
Using resonant ultrasound spectroscopy (RUS), the author will determine the complete elastic constant matrices of two thermoelectric single crystal samples, Ce.75Fe3CoSb12 and CeFe4Sb12. RUS involves measuring the resonant frequencies of a sample's vibrations, which depend on the sample's elastic constants, shape, orientation, and density. The author aims to obtain the elastic moduli from a single RUS spectrum for each sample. Understanding the elastic properties may help identify better thermoelectric materials by correlating low elastic stiffness with low thermal conductivity and higher thermoelectric efficiency. The author will compute the resonant frequencies using the samples' properties and compare to measurements.
On The Effect of Perturbations, Radiation and Triaxiality on the Stability of...IOSR Journals
This document summarizes a research paper that studied the effect of perturbations, radiation, and triaxiality on the stability of triangular libration points in the restricted three-body problem. The paper established equations of motion that account for small perturbations in coriolis and centrifugal forces when the larger primary is a triaxial rigid body and the smaller primary emits radiation. It was found that these factors affect the libration points and the critical mass value for stability. The work generalizes prior equations of motion to include these additional influences on the restricted three-body problem.
Invited Seminar presented at the VIA Forum Astroparticle Physics Forum COSMOVIA
21 March 2020
http://viavca.in2p3.fr/2010c_o_s_m_o_v_i_a__forum_sd24fsdf4zerfzef4ze5f4dsq34sdteerui45788789745rt7yr68t4y54865h45g4hfg56h45df4h86d48h48t7uertujirjtiorjhuiofgrdsqgxcvfghfg5h40yhuyir/viewtopic.php?f=73&t=3705&sid=c56cbf76f87536fc4c3ff216d9edaba2
Author: O.M. Lecian
Speaker: O.M. Lecian
Abstract: The LHAASO experiment is aimed at detecting highly-energetic particles of cosmological origin within a large
range of energies.
The sensitivity of the experimental apparatus can within the frameworks of statistical fluctuations of the
background.
Acceleration and lower-energy particles can be analyzed.
The anisotropy mass composition of cosmic rays can analytically described.
The LHAASO Experiment is also suited for detecting particles of cosmological origin originated from the breach
(and/or other kinds of modifications) of particle theories paradigms comprehending other symmetry groups.
Some physical implications of anisotropies can be looked for.
The study of anisotropy distribution for particles of cosmological origin as well as the anisotropies of their velocities
both in the case of a flat Minkowskian background as well as in the case of curved space-time can be investigated,
as far as the theoretical description of the cross-section is concerned, as well as for the theoretical expressions of
such quantities to be analyzed.
The case of a geometrical phase of particles can be schematized by means of a geometrical factor.
Particular solutions are found under suitable approximations.
A comparison with the study of ellipsoidal galaxies is achieved.
The case of particles with anisotropies in velocities falling off faster than dark matter (DM) is compared.
The study of possible anisotropies in the spatial distribution of cosmological particles can therefore be described
also deriving form the interaction of cosmic particles with the gravitational field, arising at quantum distances, at
the semiclassical level and at the classical scales, within the framework of the proper description of particles
anisotropies properties.
ABOUT NONLINEAR CLASSIC FIELD THEORY OF CONNECTED CHARGES ijrap
1) The document presents a nonlinear classical field theory of connected charges that aims to eliminate the divergence of proper energy in classical electrodynamics.
2) It constructs the theory outside of flat spacetime based on an exact solution for the field of an accelerated charge and the "Equivalent Situation Postulate".
3) The theory uses Maxwell's equations in generally covariant form and "structure equations" rather than Einstein's equations to determine the metric of non-inertial frames of reference.
Thermal Tuning of Omni-Directional Reflection Band in Si-Based 1d Photonic Cr...ijrap
The temperature dependence of the omni-directional reflection (ODR) band in a one-dimensional photonicbcrystal is proposed simultaneously considering thermal expansion effect and thermo-optic effect. The structure proposed in this study consists of a periodic arrangement of alternate layers of SiO2 as the material of low refractive index and Si as the material of high refractive index. As the refractive index and thickness of both materials used in this study are modulated by temperature, the ODR band can be tuned as a function of temperature. With the increase of temperature, it is noted that the ODR band shifts towards the longer wavelength region. Also, the ODR band broadens slightly. The ODR band can be tuned by variation in the operating temperature of the structure.
Fractional green function approach to study heat transfer through diathermaIAEME Publication
This document discusses using fractional Green's functions to study heat transfer through diathermanous (heat-transmitting) materials. It begins by introducing the assumptions and differential equation governing one-dimensional heat transfer through a semi-infinite solid exposed to a constant heat flux. It then defines the Riemann-Liouville and Caputo fractional derivatives and discusses how the fractional Green's function for the governing equation can be defined in terms of these derivatives. The solution is obtained in terms of the generalized Wright function.
UCSD NANO 266 Quantum Mechanical Modelling of Materials and Nanostructures is a graduate class that provides students with a highly practical introduction to the application of first principles quantum mechanical simulations to model, understand and predict the properties of materials and nano-structures. The syllabus includes: a brief introduction to quantum mechanics and the Hartree-Fock and density functional theory (DFT) formulations; practical simulation considerations such as convergence, selection of the appropriate functional and parameters; interpretation of the results from simulations, including the limits of accuracy of each method. Several lab sessions provide students with hands-on experience in the conduct of simulations. A key aspect of the course is in the use of programming to facilitate calculations and analysis.
Outgoing ingoingkleingordon 8th_jun19sqrdfoxtrot jp R
This document discusses solutions to the Klein-Gordon equation in Schwarzschild spacetime near a black hole's event horizon. The radial equation is approximated in the Regge-Wheeler coordinate, leading to oscillatory solutions. These solutions are then expressed as outgoing and ingoing waves, which have different properties in the future and past horizons. Near the horizon, the radial equation simplifies to an oscillatory form, allowing solutions describing outgoing and ingoing waves.
Half-metallic-ferrimagnetic Sr2CrWO6 and Sr2FeReO6 materials for room tempera...IOSR Journals
Complex perovskite-like materials which include magnetic transition elements have relevance due to
the technological perspectives in the spintronics industry. In this work, we report the studies of the electronic
and magnetic characterizations of Sr2CrWO6 and Sr2FeReO6 as spintronics materials at room temperature by
using the linearized muffin-tin orbitals (LMTO) method through the atomic-sphere approximation (ASA) within
the local spin density approximation (LSDA). The interchange-correlation potential was included through the
LSDA+U technique. The band structure results at room-temperature predict half-metallic ferrimagnetic ground
state for Sr2CrWO6 and Sr2FeReO6 with total magnetic moment of 1.878 μB and 3.184 μB per formula unit,
respectively, agreement with the previous theoretical and experimental results.
Band structure engineering of type I GaAs/AlAs nanostructure superlattice for...IJERA Editor
We report here the electronic properties of GaAs/Ga1-xAlxAs, type I superlattices for x=1, performed in the envelope function formalism. We have studied the indirect-direct band gap transition in asymmetric (GaAs)14 /(AlAs)m superlattices. Our calculations are confirmed by different experimental measurements. We have also studied the effect of the valence band offset, the temperature and the barrier thickness on the band structure of GaAs (d1=3.95 nm)/AlAs (d2=2.37 nm) superlattice. These results are in good agreement with reflectance measurements reported in literature. Finally, in the investigated temperature range, the cut-off wavelength is 716 nm ≤ λc ≤ 755 nm situates this sample as near infrared detector.
This document discusses the effects of strain on the structural, mechanical, and electronic properties of monolayer tin dioxides and dichalcogenides (SnX2 where X is O, S, Se, or Te) based on first-principles calculations. It finds that the 1T phase is more stable than the 2H phase, and strain affects the bond lengths and band gaps of the materials. Applied strain decreases the band gaps of both phases linearly by altering the orbital distributions, and can cause a semiconductor-metal transition in the 2H phase.
This document discusses the strain tunable structural, mechanical, and electronic properties of monolayer tin dioxides and dichalcogenides (SnX2 where X is O, S, Se, Te) based on first-principles calculations. The key findings are: 1) Monolayer 1T-SnX2 is found to be more energetically stable than 2H-SnX2, while 2H-SnX2 has a much higher stiffness. 2) Applying external strain decreases the band gaps of both 2H- and 1T-SnO2 linearly, with the slope of the band gap variation for biaxially strained 1T-SnO2 reaching -0.16 eV
This document describes an experiment to observe and record the surface plasmon resonance (SPR) curve for a thin metal film. Light from a laser is shone through a glass prism onto the metal film at varying angles of incidence. The intensity of the reflected light is recorded versus the angle to generate the SPR curve. Surface plasmons are quantum phenomena that can be excited at the metal-air interface by photons and decay back into photons. The SPR curve depends on the dielectric constant of the metal film and its thickness. Matching the wavevector of incident light to that of surface plasmons requires increasing the wavevector by passing light through a higher index material like glass before it reaches the metal film.
Multi wavelenth observations and surveys of galaxy clustersJoana Santos
This document provides an overview of galaxy clusters, focusing on their baryonic components (intracluster medium and galaxies) and how they relate to the cluster's physical properties like mass. It discusses that galaxy clusters form hierarchically through gravitational collapse. The intracluster medium, which makes up most of the baryonic mass, emits X-rays and has been heated to temperatures of millions of degrees. The document reviews properties of the intracluster medium like density, temperature, metallicity, and how they can be measured from X-ray spectra. It also discusses upcoming surveys that will advance the study of galaxy clusters.
Stability Of Magnetostatic Surface Waves In A Semiconductor-Ferrite-Left-Hand...ijrap
This document discusses the stability of magnetostatic surface waves in a waveguide structure composed of a semiconductor layer, ferrite layer, and left-handed material layer. It presents the dispersion relations that describe magnetostatic surface waves in this three-layer structure. The relations show the waves can have both positive and negative components, indicating forward and backward waves. Graphs show how the wave characteristics, such as attenuation and wavelength, are affected by parameters like conductivity, drift velocity of carriers, and the fill factor of the left-handed material. The document concludes by discussing the possibility of magnetostatic surface envelop solitons existing during propagation of the magnetostatic surface waves in this waveguide structure.
This document presents a theoretical treatment of charge exchange processes that can occur during the scattering of positively charged lithium ions (Li+) from the surface of a narrow band insulator (KF) in the presence of a laser field. Equations are derived to describe the dynamics and describe how the laser field can be incorporated into the system Hamiltonian. The treatment is then applied to model charge exchange during the scattering of Li+ from KF surfaces. The key conclusions are that the charge state of the scattering species can be controlled by adjusting parameters of the applied laser field, such as frequency and intensity.
1) The paper investigates whether quantum variations around geodesics could circumvent caustics that occur in certain space-times.
2) An action is developed that yields both the field equations and geodesic condition. Quantizing this action provides a way to determine the extent of the wave packet around the classical path.
3) It is shown that replacing plane wave solutions with wave packets in the path integral still yields acceptable results. Determining if the distribution matches expectation values and variances is key to establishing geodesic completeness with quantum variations.
This document discusses the hydrodynamic equations that describe neutral gas and plasma, and how they are modified to become the magnetohydrodynamic (MHD) equations when a conducting fluid is in a magnetic field. It introduces the continuity, momentum, and entropy equations for neutral gas hydrodynamics. It then explains how these are updated to the MHD equations by adding magnetic forces and Ohm's law relating current and fields. The key MHD equations derived include equations for momentum, entropy, and the magnetic field evolving due to motion and diffusion.
Research Inventy : International Journal of Engineering and Scienceresearchinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
This document summarizes research on weak elastic anisotropy in geological materials. It finds that while most rocks exhibit some anisotropy, the anisotropy is often weak, defined as less than 20%. In cases of weak anisotropy, the equations governing wave propagation simplify significantly. Specifically, a parameter called delta (δ) emerges as the most important measure of anisotropy, rather than differences in vertical and horizontal velocities. The parameter δ does not involve horizontal velocity and may be positive or negative. Using δ, the document analyzes how weak anisotropy affects seismic exploration techniques like reflection profiling, even when the anisotropy is small.
EVALUATING STRUCTURAL, OPTICAL & ELECTRICAL CHARACTERIZATION OF ZINC CHALCOGE...Editor IJCATR
To evaluate the structural, optical & electrical properties of the zinc chalcogenides (ZnO, ZnS, ZnSe & ZnTe), the Full
Potential Linearized – Augumented Plane Wave plus Local Orbits (FP – LAPW+lo) method. For the purpose of exchange-correlation
energy (Exc) determination in Kohn–Sham calculation, the standard local density approximation (LDA) formalism has been utilized.
Murnaghan’s equation of state (EOS) has been used for volume optimization by minimizing the total energy with respect to the unit
cell volume. With the result of electronic density of states (DOS), the structural, optical and electrical properties of Zinc chalcogenides
have been calculated. The second derivative of energy, as a function of lattice strain has been successfully used to estimate the elastic
constants of these binary compounds. The results are in good agreement with other theoretical calculations as well as available
experimental data.
Using resonant ultrasound spectroscopy (RUS), the author will determine the complete elastic constant matrices of two thermoelectric single crystal samples, Ce.75Fe3CoSb12 and CeFe4Sb12. RUS involves measuring the resonant frequencies of a sample's vibrations, which depend on the sample's elastic constants, shape, orientation, and density. The author aims to obtain the elastic moduli from a single RUS spectrum for each sample. Understanding the elastic properties may help identify better thermoelectric materials by correlating low elastic stiffness with low thermal conductivity and higher thermoelectric efficiency. The author will compute the resonant frequencies using the samples' properties and compare to measurements.
On The Effect of Perturbations, Radiation and Triaxiality on the Stability of...IOSR Journals
This document summarizes a research paper that studied the effect of perturbations, radiation, and triaxiality on the stability of triangular libration points in the restricted three-body problem. The paper established equations of motion that account for small perturbations in coriolis and centrifugal forces when the larger primary is a triaxial rigid body and the smaller primary emits radiation. It was found that these factors affect the libration points and the critical mass value for stability. The work generalizes prior equations of motion to include these additional influences on the restricted three-body problem.
Invited Seminar presented at the VIA Forum Astroparticle Physics Forum COSMOVIA
21 March 2020
http://viavca.in2p3.fr/2010c_o_s_m_o_v_i_a__forum_sd24fsdf4zerfzef4ze5f4dsq34sdteerui45788789745rt7yr68t4y54865h45g4hfg56h45df4h86d48h48t7uertujirjtiorjhuiofgrdsqgxcvfghfg5h40yhuyir/viewtopic.php?f=73&t=3705&sid=c56cbf76f87536fc4c3ff216d9edaba2
Author: O.M. Lecian
Speaker: O.M. Lecian
Abstract: The LHAASO experiment is aimed at detecting highly-energetic particles of cosmological origin within a large
range of energies.
The sensitivity of the experimental apparatus can within the frameworks of statistical fluctuations of the
background.
Acceleration and lower-energy particles can be analyzed.
The anisotropy mass composition of cosmic rays can analytically described.
The LHAASO Experiment is also suited for detecting particles of cosmological origin originated from the breach
(and/or other kinds of modifications) of particle theories paradigms comprehending other symmetry groups.
Some physical implications of anisotropies can be looked for.
The study of anisotropy distribution for particles of cosmological origin as well as the anisotropies of their velocities
both in the case of a flat Minkowskian background as well as in the case of curved space-time can be investigated,
as far as the theoretical description of the cross-section is concerned, as well as for the theoretical expressions of
such quantities to be analyzed.
The case of a geometrical phase of particles can be schematized by means of a geometrical factor.
Particular solutions are found under suitable approximations.
A comparison with the study of ellipsoidal galaxies is achieved.
The case of particles with anisotropies in velocities falling off faster than dark matter (DM) is compared.
The study of possible anisotropies in the spatial distribution of cosmological particles can therefore be described
also deriving form the interaction of cosmic particles with the gravitational field, arising at quantum distances, at
the semiclassical level and at the classical scales, within the framework of the proper description of particles
anisotropies properties.
ABOUT NONLINEAR CLASSIC FIELD THEORY OF CONNECTED CHARGES ijrap
1) The document presents a nonlinear classical field theory of connected charges that aims to eliminate the divergence of proper energy in classical electrodynamics.
2) It constructs the theory outside of flat spacetime based on an exact solution for the field of an accelerated charge and the "Equivalent Situation Postulate".
3) The theory uses Maxwell's equations in generally covariant form and "structure equations" rather than Einstein's equations to determine the metric of non-inertial frames of reference.
Thermal Tuning of Omni-Directional Reflection Band in Si-Based 1d Photonic Cr...ijrap
The temperature dependence of the omni-directional reflection (ODR) band in a one-dimensional photonicbcrystal is proposed simultaneously considering thermal expansion effect and thermo-optic effect. The structure proposed in this study consists of a periodic arrangement of alternate layers of SiO2 as the material of low refractive index and Si as the material of high refractive index. As the refractive index and thickness of both materials used in this study are modulated by temperature, the ODR band can be tuned as a function of temperature. With the increase of temperature, it is noted that the ODR band shifts towards the longer wavelength region. Also, the ODR band broadens slightly. The ODR band can be tuned by variation in the operating temperature of the structure.
Fractional green function approach to study heat transfer through diathermaIAEME Publication
This document discusses using fractional Green's functions to study heat transfer through diathermanous (heat-transmitting) materials. It begins by introducing the assumptions and differential equation governing one-dimensional heat transfer through a semi-infinite solid exposed to a constant heat flux. It then defines the Riemann-Liouville and Caputo fractional derivatives and discusses how the fractional Green's function for the governing equation can be defined in terms of these derivatives. The solution is obtained in terms of the generalized Wright function.
UCSD NANO 266 Quantum Mechanical Modelling of Materials and Nanostructures is a graduate class that provides students with a highly practical introduction to the application of first principles quantum mechanical simulations to model, understand and predict the properties of materials and nano-structures. The syllabus includes: a brief introduction to quantum mechanics and the Hartree-Fock and density functional theory (DFT) formulations; practical simulation considerations such as convergence, selection of the appropriate functional and parameters; interpretation of the results from simulations, including the limits of accuracy of each method. Several lab sessions provide students with hands-on experience in the conduct of simulations. A key aspect of the course is in the use of programming to facilitate calculations and analysis.
Outgoing ingoingkleingordon 8th_jun19sqrdfoxtrot jp R
This document discusses solutions to the Klein-Gordon equation in Schwarzschild spacetime near a black hole's event horizon. The radial equation is approximated in the Regge-Wheeler coordinate, leading to oscillatory solutions. These solutions are then expressed as outgoing and ingoing waves, which have different properties in the future and past horizons. Near the horizon, the radial equation simplifies to an oscillatory form, allowing solutions describing outgoing and ingoing waves.
Half-metallic-ferrimagnetic Sr2CrWO6 and Sr2FeReO6 materials for room tempera...IOSR Journals
Complex perovskite-like materials which include magnetic transition elements have relevance due to
the technological perspectives in the spintronics industry. In this work, we report the studies of the electronic
and magnetic characterizations of Sr2CrWO6 and Sr2FeReO6 as spintronics materials at room temperature by
using the linearized muffin-tin orbitals (LMTO) method through the atomic-sphere approximation (ASA) within
the local spin density approximation (LSDA). The interchange-correlation potential was included through the
LSDA+U technique. The band structure results at room-temperature predict half-metallic ferrimagnetic ground
state for Sr2CrWO6 and Sr2FeReO6 with total magnetic moment of 1.878 μB and 3.184 μB per formula unit,
respectively, agreement with the previous theoretical and experimental results.
Band structure engineering of type I GaAs/AlAs nanostructure superlattice for...IJERA Editor
We report here the electronic properties of GaAs/Ga1-xAlxAs, type I superlattices for x=1, performed in the envelope function formalism. We have studied the indirect-direct band gap transition in asymmetric (GaAs)14 /(AlAs)m superlattices. Our calculations are confirmed by different experimental measurements. We have also studied the effect of the valence band offset, the temperature and the barrier thickness on the band structure of GaAs (d1=3.95 nm)/AlAs (d2=2.37 nm) superlattice. These results are in good agreement with reflectance measurements reported in literature. Finally, in the investigated temperature range, the cut-off wavelength is 716 nm ≤ λc ≤ 755 nm situates this sample as near infrared detector.
This document discusses the effects of strain on the structural, mechanical, and electronic properties of monolayer tin dioxides and dichalcogenides (SnX2 where X is O, S, Se, or Te) based on first-principles calculations. It finds that the 1T phase is more stable than the 2H phase, and strain affects the bond lengths and band gaps of the materials. Applied strain decreases the band gaps of both phases linearly by altering the orbital distributions, and can cause a semiconductor-metal transition in the 2H phase.
This document discusses the strain tunable structural, mechanical, and electronic properties of monolayer tin dioxides and dichalcogenides (SnX2 where X is O, S, Se, Te) based on first-principles calculations. The key findings are: 1) Monolayer 1T-SnX2 is found to be more energetically stable than 2H-SnX2, while 2H-SnX2 has a much higher stiffness. 2) Applying external strain decreases the band gaps of both 2H- and 1T-SnO2 linearly, with the slope of the band gap variation for biaxially strained 1T-SnO2 reaching -0.16 eV
This document describes an experiment to observe and record the surface plasmon resonance (SPR) curve for a thin metal film. Light from a laser is shone through a glass prism onto the metal film at varying angles of incidence. The intensity of the reflected light is recorded versus the angle to generate the SPR curve. Surface plasmons are quantum phenomena that can be excited at the metal-air interface by photons and decay back into photons. The SPR curve depends on the dielectric constant of the metal film and its thickness. Matching the wavevector of incident light to that of surface plasmons requires increasing the wavevector by passing light through a higher index material like glass before it reaches the metal film.
Multi wavelenth observations and surveys of galaxy clustersJoana Santos
This document provides an overview of galaxy clusters, focusing on their baryonic components (intracluster medium and galaxies) and how they relate to the cluster's physical properties like mass. It discusses that galaxy clusters form hierarchically through gravitational collapse. The intracluster medium, which makes up most of the baryonic mass, emits X-rays and has been heated to temperatures of millions of degrees. The document reviews properties of the intracluster medium like density, temperature, metallicity, and how they can be measured from X-ray spectra. It also discusses upcoming surveys that will advance the study of galaxy clusters.
Stability Of Magnetostatic Surface Waves In A Semiconductor-Ferrite-Left-Hand...ijrap
This document discusses the stability of magnetostatic surface waves in a waveguide structure composed of a semiconductor layer, ferrite layer, and left-handed material layer. It presents the dispersion relations that describe magnetostatic surface waves in this three-layer structure. The relations show the waves can have both positive and negative components, indicating forward and backward waves. Graphs show how the wave characteristics, such as attenuation and wavelength, are affected by parameters like conductivity, drift velocity of carriers, and the fill factor of the left-handed material. The document concludes by discussing the possibility of magnetostatic surface envelop solitons existing during propagation of the magnetostatic surface waves in this waveguide structure.
This document presents a theoretical treatment of charge exchange processes that can occur during the scattering of positively charged lithium ions (Li+) from the surface of a narrow band insulator (KF) in the presence of a laser field. Equations are derived to describe the dynamics and describe how the laser field can be incorporated into the system Hamiltonian. The treatment is then applied to model charge exchange during the scattering of Li+ from KF surfaces. The key conclusions are that the charge state of the scattering species can be controlled by adjusting parameters of the applied laser field, such as frequency and intensity.
Magnetostatic Surface Waves in a Left Handed / Ferrite/ Metal-Strip-Grating ...ijrap
The dispersion characteristics for magnetostatic surface waves in a left handed ( LHM)/ferrite/ metal-stripgrating structure have been investigated. We found that, the waveguide supports backward TE waves
since both permittivity and magnetic permeability of LHM are negative. We also illustrated the
dependence of wave frequency on the reduced wave number for a grating shielding parameter, g values
restricted by the range 0 ≤ g ≥ 1. It is shown that the grating shielding parameter, g induces
magnetostatic backward shorter waves . The leakage through the grating increases with the wave number.
The shorter backward magnetostatic waves are guided by the thicker waveguide where the best
confinement is achieved .
A review of progress in modelling induced geoelectric andoilandgas24
This document reviews progress in modelling induced geoelectric and geomagnetic fields, specifically regarding geomagnetically induced currents (GICs). It summarizes recent studies that have improved understanding of the 3D electrical conductivity structure of Earth from global and regional surveys. It also highlights advances in integrated models of geomagnetic and geoelectric fields across Europe to better model GIC effects in power grids and pipelines. Recent findings on deep mantle conductivity from satellite data and refinements to regional models from magnetotelluric surveys are discussed. Modelling techniques like the complex image method are also reviewed.
Stability Of Magnetostatic Surface Waves In A Semiconductor-Ferrite-Left-Hand...ijrap
1) The document investigates magnetostatic surface waves in a waveguide structure composed of a ferrite layer sandwiched between a semiconductor layer and a left-handed material substrate.
2) It presents dispersion relations that describe the propagation of magnetostatic surface waves in the structure and show the waves can have forward or backward propagation depending on frequency and applied magnetic field direction.
3) Graphs show how the wave index and attenuation are affected by parameters like conductivity, drift velocity of carriers, and fill factor of the left-handed material.
Phase transition and the Casimir effect are studied in the complex scalar field with one spatial dimension to be compactified. It is shown that the phase transition is of the second order and the Casimir effect behaves quite differently
depending on whether it’s under periodic or anti-periodic boundary conditions
This document discusses how nonlinear electrodynamics (NLED) may provide a mechanism for forming astrophysical charged black holes during gravitational core collapse supernovae. NLED allows the timescale for charge neutralization in a proto-neutron star to be longer than the gravitational collapse timescale, preventing neutralization and allowing the core to collapse while positively charged. This could result in a charged black hole. The document outlines the theoretical framework of NLED, how it exhibits an inherent repulsive action, and how this could keep the charge separation state of a proto-neutron star stalled long enough for gravitational collapse to occur, forming an astrophysical charged black hole.
This document discusses Bose-Einstein condensation controlled by a combination of trapping potentials, including a harmonic oscillator potential (HOP) along the x-axis and an optical lattice potential (OLP) along the y-axis. It analyzes how parameters in the HOP and OLP, such as the anisotropy parameter and q parameter, affect properties of the trapping potential, initial and final wave functions, and chemical potential. The study uses the Gross-Pitaevskii equation and Crank-Nicolson numerical method to solve for the wave function under different trapping conditions. Results show relationships between the chemical potential and the HOP anisotropy/OLP q parameter, as well as the distribution of
New Constraints on Warm Dark Matter from the Lyman-α Forest Power SpectrumSérgio Sacani
The forest of Lyman-α absorption lines detected in the spectra of distant quasars encodes information on the nature and properties of dark matter and the thermodynamics of diffuse baryonic
material. Its main observable – the 1D flux power spectrum (FPS) – should exhibit a suppression on
small scales and an enhancement on large scales in warm dark matter (WDM) cosmologies compared
to standard ΛCDM. Here, we present an unprecedented suite of 1080 high-resolution cosmological
hydrodynamical simulations run with the Graphics Processing Unit-accelerated code Cholla to
study the evolution of the Lyman-α forest under a wide range of physically-motivated gas thermal
histories along with different free-streaming lengths of WDM thermal relics in the early Universe. A
statistical comparison of synthetic data with the forest FPS measured down to the smallest velocity
scales ever probed at redshifts 4.0 ∼
< z ∼
< 5.2 [1] yields a lower limit mWDM > 3.1 keV (95 percent
CL) for the WDM particle mass and constrains the amplitude and spectrum of the photoheating
and photoionizing background produced by star-forming galaxies and active galactic nuclei at these
redshifts. Interestingly, our Bayesian inference analysis appears to weakly favor WDM models with a
peak likelihood value at the thermal relic mass of mWDM = 4.5 keV. We find that the suppression of
the FPS from free-streaming saturates at k ∼
> 0.1 s km−1 because of peculiar velocity smearing, and
this saturated suppression combined with a slightly lower gas temperature provides a moderately
better fit to the observed small-scale FPS for WDM cosmologies.
Numerical studies of the radiation patterns of resistively loaded dipolesLeonid Krinitsky
This document describes a numerical study of the radiation patterns of resistively loaded dipole antennas. It computes the far field radiation patterns as a superposition of transient solutions for infinitesimal dipole elements. The current excitation for each dipole element is modeled as a half cycle of a sine squared waveform that propagates along the antenna at an adjustable speed. The radiation patterns are presented for different dielectric media to model antennas used in ground penetrating radar applications in various materials like water, ice, and soil. Comparisons are made to field observations.
Electron acoustic waves are high frequency electrostatic waves that exist in plasmas containing two populations of electrons with different temperatures, as well as a background of ions. They were first introduced by Fried and Gould in 1961 as a solution to the Vlasov dispersion equation. Electron acoustic waves propagate due to interactions between the electron populations, and their study is important for interpreting electrostatic noise observed in space plasmas like the Earth's magnetosphere. Research on nonlinear propagation of electron acoustic waves continues to provide insights into wave phenomena in multi-temperature plasmas.
FOR HUMANITY: (V4) A BREAKTHROUGH IN TOKAMAK APPLIED PHYSICS GRAVITATIONAL WA...GLOBAL HEAVYLIFT HOLDINGS
The document discusses using a Tokamak fusion reactor to generate detectable gravitational waves. It finds that utilizing plasma drift currents could generate strain amplitudes of around 10-25 five meters above the center of the Tokamak, allowing possible detection in the coming decade. This is an order of magnitude greater than estimates using simple Ohm's law. The document outlines the theory and provides equations, figures, and a table of strain estimates for different Tokamaks to support these conclusions.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document summarizes a research paper that proposes a new metamaterial shape called "Criss-Cross" and analyzes its electromagnetic properties. The paper derives mathematical models to calculate the reflection and transmission coefficients for electromagnetic waves propagating through stratified negative index metamaterials. Simulation results show the Criss-Cross metamaterial exhibits negative effective permittivity and permeability over a wide frequency band of 5-9 GHz. This 61.53% negative parameter bandwidth is significantly larger than other metamaterial designs. Finally, the paper proposes using a 3x3 array of the Criss-Cross unit cell to miniaturize the size of a rectangular patch antenna.
MUSE sneaks a peek at extreme ram-pressure stripping events. I. A kinematic s...Sérgio Sacani
- MUSE observations of the galaxy ESO137-001 reveal an extended gaseous tail over 30 kpc long traced by H-alpha emission, providing evidence of an extreme ram pressure stripping event as the galaxy falls into the massive Norma galaxy cluster.
- Analysis of the H-alpha kinematics and stellar velocity field show that ram pressure has removed the interstellar medium from the outer disk while the primary tail is still fed by gas from the galaxy center, with gravitational interactions not appearing to be the main mechanism of gas removal.
- The stripped gas retains evidence of the disk's rotational velocity out to around 20 kpc downstream, indicating the galaxy is moving radially along the plane of the sky, while
Similar to Surface Polaritons in GAAS/ALGAAS/LH Hetrojunction Structure in a High Magnetic Field (20)
New Thermodynamics: A Superior Fit Revised Kinetic Theoryijrap
The accepted kinetic theory forms a basis for modern thermodynamics and is mathematically based upon equipartition and degrees of freedom. It remains plagued with the necessity of numerous degrees of freedom exceptions for it to explain both empirically determined heat capacities and adiabatic indexes. Furthermore, assuming kT/2 per degree of freedom is to accept that a gas molecule possesses a specified energy without providing any clarity concerning that energy’s origins. Energy without an origin contravenes the first law of thermodynamics. This author’s previously published superior fit kinetic theory will be clarified and elaborated upon. This includes showing that this revised kinetic theory is a superior fit to both known heat capacities and adiabatic indexes. Not only is it a superior fit that does not rely upon any exceptions, this author’s kinetic theory also provides insight into the actual sources of a gas molecule’s energy. Furthermore, clarity concerning the difference between isometric (isochoric) and isobaric heat capacities in terms of sensible work will be discussed, along withits likely empirical verification.
On the Unification of Physic and the Elimination of Unbound Quantitiesijrap
This paper supports Descartes' idea of a constant quantity of motion, modernized by Leibniz. Unlike Leibniz, the paper emphasizes that the idea is not realized by forms of energy, but by energy itself. It remains constant regardless of the form, type, or speed of motion, even that of light. Through force, energy is only transformed. Here it is proved that force is its derivative. It exists even at rest, representing the object's minimal energy state. With speed, we achieve its multiplication up to the maximum energy state, from which a maximum force is derived from the object. From this point, corresponding to Planck's Length, we find the value of the force wherever we want. Achieving this removes the differences between various natural forces. The new idea eliminates infinite magnitudes. The process allows the laws to transition from simple to complex forms and vice versa, through differentiation-integration. For this paper, this means achieving the Unification Theory.
Gravity Also Redshifts Light – the Missing Phenomenon That Could Resolve Most...ijrap
In this paper I discover that gravity also redshifts light like the velocity of its source does. When light travels towards a supermassive object, its waves (or photons) undergo continuous stretching, thereby shifting towards lower frequencies. Gravity redshifts light irrespective of whether its source is in motion or static with respect to its observer. An equation is derived for gravitational redshift, and a formula for combined redshift is presented by considering both the velocity, and gravity redshifts. Also explained is how frequencies of electromagnetic spectrum continuously downgrade as a light beam of mix frequencies passes towards a black hole. Further, a clear methodology is provided to figure out whether expansion of the universe is accelerating or decelerating, or alternatively, the universe is contracting.
In this paper I present a new theory that explains as to when and how dark energy is created as mass is destroyed. The theory extends Einstein’s mass energy equation to a more generic form in order to make it work even in high gravity conditions. It also explains why dark energy is created. Further, it is proved Einstein’s mass energy equation holds good only when the destroyed mass has no supermassive object in its close vicinity. The relationship between dark energy and dark matter is unveiled. An extended mathematical form of Einstein’s mass energy equation is derived, based on which the conditions leading to dark energy creation are explained. Three new physical parameters called dark energy discriminant, dark energy radius and dark energy boundary are introduced to facilitate easy understanding of the theory. It is explained in detail that an extremely superdense object has two dark energy boundaries, outer and inner. Mass destroyed only between these two boundaries creates dark energy. Dark energy space, the space between the two aforementioned boundaries, shrouds visible matter in obscurity from optical and electromagnetic telescopes. This theory identifies Gargantuan as a superdense black hole currently creating fresh dark energy, which could be the subject of interest for the astronomical research community having access to sophisticated telescopes, and working on dark energy. It also upholds dark energy and denies the existence of dark matter. Dark matter is nothing but the well-known visible matter positioned in dark energy space. An important relationship is derived between a photon’s frequency and its distance from a black hole to demonstrate the effect of gravity on light. Another important fact revealed by this theory is gravity stretches out light, thereby causing redshift, which is unaccounted in the computation of velocities of outer galaxies. Whether the universe is undergoing accelerated or decelerated expansion, or accelerated contraction can precisely be determined only after accounting for the redshift caused by gravity
International Journal on Soft Computing, Artificial Intelligence and Applicat...ijrap
International Journal on Soft Computing, Artificial Intelligence and Applications (IJSCAI)
is an open access peer-reviewed journal that provides an excellent international forum for sharing
knowledge and results in theory, methodology and applications of Artificial Intelligence, Soft
Computing. The Journal looks for significant contributions to all major fields of the Artificial
Intelligence, Soft Computing in theoretical and practical aspects. The aim of the Journal is to
provide a platform to the researchers and practitioners from both academia as well as industry to
meet and share cutting-edge development in the field.
Authors are solicited to contribute to the journal by submitting articles that illustrate research
results, projects, surveying works and industrial experiences that describe significant advances in
the areas of Database management systems.
SOME THEORETICAL ASPECTS OF HYDROGEN DIFFUSION IN BCC METALS AT LOW TEMPERATURESijrap
Purpose of the work is to discuss some theoretical aspects of the diffusion of hydrogen atoms in the crystal
lattice of BCC metals at low temperatures using the methods of statistical thermodynamics. The values of
the statistical model calculations of H diffusion coefficients in α-Fe, V, Ta, Nb, K are in good agreement
with the experimental data. The statistical model can also explain deviations from the Arrhenius equation
at temperatures 300-100 K in α-Fe, V, Nb and K. It was suggested that thermally activated fast tunnelling
transition of hydrogen atoms through the potential barrier at a temperature below 300 K provides an
almost free movement of H atoms in the α-Fe and V lattice at these temperatures. The results show that
quantum-statistical effects play a decisive role in the H diffusion in BCC metals at low temperatures. Using
the statistical model allows for the prediction of the diffusion coefficient for H in BCC metals at low
temperatures, where it’s necessary to consider quantum effects.
MASSIVE PHOTON HYPOTHESIS OPENS DOORS TO NEW FIELDS OF RESEARCHijrap
1) A massive photon hypothesis is proposed, where the photon mass is directly calculated from kinetic gas theory to be 1.25605 x 10-39 kg.
2) This photon mass explains various experiments like light deflection near the Sun and the gravitational redshift.
3) The photon gas is found to behave as a perfect blackbody and ideal gas, with photons having 6 degrees of freedom.
4) The thermal de Broglie wavelength of this photon gas is calculated to be 1.75967 x 10-3 m, matching the wavelength of the cosmic microwave background radiation.
5) This links the CMB radiation to being continuously generated by the photon gas permeating space, rather than being a relic of
PHENOMENOLOGICAL METHOD REGARDING A THIRD THEORY OF PHYSICS “THE EVENT:THE TH...ijrap
The quest for a third theory uniting macro-cosmos (relativity) and micro-cosmos (quantum mechanics) has coexisted with the denial of feminine/subjective polarity to masculine/objective. The dismissal of electromagnetism as the tension of opposites in quest of inner/outer unity is sourced in the denial of the feminine qualia -- the negative force field attributed to dark energy/dark matter. However, a conversion philosophy sourced in the hieros gamos and signified by the Mobius strip has formulated an integral consciousness methodology producing quantum objects by means of embracing the shadow haunting contemporary physics. This Self-reflecting process integrating subject/object comprises an ontology of kairos as the “quantum leap.” An interdisciplinary quest to create a phenomenological narrative is disclosed via a holistic apparatus of hermeneutics manifesting image/text of a contemporary grail journey. Reflected in this Third space is the sacred reality of autonomous number unifying polarities of feminine/subjective (quality) and objective/masculine (quantity) as new measurement apparatus for the quantum wave collapse.
3rd International Conference on Integrating Technology in Education (ITE 2022)ijrap
3rd International Conference on Integrating Technology in Education (ITE 2022) This forum also aims to provide a platform for exchanging ideas in new emerging trends that needs more focus and exposure and will attempt to publish proposals that strengthen our goals.
A SPECIAL RELATIONSHIP BETWEEN MATTER, ENERGY, INFORMATION, AND CONSCIOUSNESSijrap
This paper discusses the advantages of describing the universe, or nature, in terms of information and consciousness. Some problems encountered by theoretical physicists in the quest for the theory of everything stem from the limitations of trying to understand everything in terms of matter and energy only. However, if everything, including matter, energy, life, and mental processes, is described in terms of information and consciousness, much progress can be made in the search for the ultimate theory of the universe. As brilliant and successful as physics and chemistry have been over the last two centuries, it is important that nature is not viewed solely in terms of matter and energy. Two additional components are needed to unlock her secrets. While extensive writing exists that describes the connection between matter and energy and their physical basis, little work has been done to learn the special relationship between matter, energy, information, and consciousness.
This paper discusses the advantages of describing the universe, or nature, in terms of information and consciousness. Some problems encountered by theoretical physicists in the quest for the theory of everything stem from the limitations of trying to understand everything in terms of matter and energy only. However, if everything, including matter, energy, life, and mental processes, is described in terms of information and consciousness, much progress can be made in the search for the ultimate theory of the universe. As brilliant and successful as physics and chemistry have been over the last two centuries, it is important that nature is not viewed solely in terms of matter and energy. Two additional components are needed to unlock her secrets. While extensive writing exists that describes the connection between matter and energy and their physical basis, little work has been done to learn the special relationship between matter, energy, information, and
consciousness.
THE CONCEPT OF SPACE AND TIME: AN AFRICAN PERSPECTIVEijrap
Understanding the concept of space and time is critical, essential, and fundamental in searching for theall-encompassing theory or the theory of everything (ToE). Some physicists argue that time exists, whileothers posit that time is only a social or mental construct. The author presents an African thought systemon space and time conception, focusing on the African (Bantu) view of space and time. The author arguesthat before the advent of the Western linear view of space and time, Africans had their own visionregarding these two concepts. Their conception of time appears to be holistic, highly philosophical, non-linear, and thought-provoking. The author hopes that exploring these two concepts from an African perspective will provide a new and more in-depth insight into reality's nature. A scientific investigation of space and time from an African-centered perspective is a worthy and necessary endeavor in the quest forthe ToE
Learning to Pronounce as Measuring Cross Lingual Joint Orthography Phonology ...ijrap
Machine learning models allow us to compare languages by showing how hard a task in each language might be to learn and perform well on. Following this line of investigation, we explore what makes a language “hard to pronounce” by modelling the task of grapheme-to-phoneme (g2p) transliteration. By training a character-level transformer model on this task across 22 languages and measuring the model’s proficiency against its grapheme and phoneme inventories, we show that certain characteristics emerge that separate easier and harder languages with respect to learning to pronounce. Namely the complexity of a language's pronunciation from its orthography is due to the expressive or simplicity of its grapheme-to phoneme mapping. Further discussion illustrates how future studies should consider relative data sparsity per language to design fairer cross-lingual comparison tasks.
THE CONCEPT OF SPACE AND TIME: AN AFRICAN PERSPECTIVEijrap
Understanding the concept of space and time is critical, essential, and fundamental in searching for the all-encompassing theory or the theory of everything (ToE). Some physicists argue that time exists, while others posit that time is only a social or mental construct. The author presents an African thought system on space and time conception, focusing on the African (Bantu) view of space and time. The author argues
that before the advent of the Western linear view of space and time, Africans had their own vision
regarding these two concepts. Their conception of time appears to be holistic, highly philosophical, nonlinear, and thought-provoking. The author hopes that exploring these two concepts from an African
perspective will provide a new and more in-depth insight into reality's nature. A scientific investigation of space and time from an African-centered perspective is a worthy and necessary endeavor in the quest for the ToE.
International Journal of Recent advances in Physics (IJRAP)ijrap
International Journal of Recent advances in Physics (IJRAP) is a peer-reviewed, open access journal, addresses the impacts and challenges of Physics. The journal documents practical and theoretical results which make a fundamental contribution for the development of Physics.
The Concept of Space and Time: An African Perspectiveijrap
Understanding the concept of space and time is critical, essential, and fundamental in searching for the all-encompassing theory or the theory of everything (ToE). Some physicists argue that time exists, while others posit that time is only a social or mental construct. The author presents an African thought system on space and time conception, focusing on the African (Bantu) view of space and time. The author argues that before the advent of the Western linear view of space and time, Africans had their own vision regarding these two concepts. Their conception of time appears to be holistic, highly philosophical, nonlinear, and thought-provoking. The author hopes that exploring these two concepts from an African perspective will provide a new and more in-depth insight into reality's nature. A scientific investigation of space and time from an African-centered perspective is a worthy and necessary endeavor in the quest for the ToE.
The majority of physicists take it for granted that the universe is made up of matter. In turn, matter is composed of atoms; atoms are made up of particles such as electrons, protons, neutrons, etc. Also, protons
and neutrons are composed of quarks, etc. Furthermore, that everything in nature is governed by the known laws of physics and chemistry. The author only partially shares this view. He argues that many phenomena in the universe may depend on rules or factors as yet incorporated by the physical sciences.
The last few years have led him to reflect on the many unsolved physics problems, such as the quest for the theory of everything (ToE), the arrow of time, the interpretation of quantum mechanics, the fine-tuned
universe, etc. to mention just a few. The author posits that a field carries information, performs various mathematical and computational operations, and behaves as an intelligent entity embedded with consciousness.
Call For Papers - International Journal of Recent advances in Physics (IJRAP)ijrap
International Journal of Recent advances in Physics (IJRAP) is a peer-reviewed, open access journal, addresses the impacts and challenges of Physics. The journal documents practical and theoretical results which make a fundamental contribution for the development of Physics.
Call For Papers - International Journal of Recent advances in Physics (IJRAP)ijrap
The International Journal of Recent Advances in Physics (IJRAP) is a peer-reviewed open access journal that addresses impacts and challenges in the field of physics. It covers theoretical and practical results across many areas of physics including advanced functional materials, applied optics, condensed matter physics, nuclear physics, quantum physics, and more. Authors are invited to submit papers by email before October 30, 2021. Notifications of acceptance will be provided by November 25, 2021.
Call For Papers - International Journal of Recent advances in Physics (IJRAP)ijrap
International Journal of Recent advances in Physics (IJRAP) is a peer-reviewed, open access journal, addresses the impacts and challenges of Physics. The journal documents practical and theoretical results which make a fundamental contribution for the development of Physics.
Microbial interaction
Microorganisms interacts with each other and can be physically associated with another organisms in a variety of ways.
One organism can be located on the surface of another organism as an ectobiont or located within another organism as endobiont.
Microbial interaction may be positive such as mutualism, proto-cooperation, commensalism or may be negative such as parasitism, predation or competition
Types of microbial interaction
Positive interaction: mutualism, proto-cooperation, commensalism
Negative interaction: Ammensalism (antagonism), parasitism, predation, competition
I. Mutualism:
It is defined as the relationship in which each organism in interaction gets benefits from association. It is an obligatory relationship in which mutualist and host are metabolically dependent on each other.
Mutualistic relationship is very specific where one member of association cannot be replaced by another species.
Mutualism require close physical contact between interacting organisms.
Relationship of mutualism allows organisms to exist in habitat that could not occupied by either species alone.
Mutualistic relationship between organisms allows them to act as a single organism.
Examples of mutualism:
i. Lichens:
Lichens are excellent example of mutualism.
They are the association of specific fungi and certain genus of algae. In lichen, fungal partner is called mycobiont and algal partner is called
II. Syntrophism:
It is an association in which the growth of one organism either depends on or improved by the substrate provided by another organism.
In syntrophism both organism in association gets benefits.
Compound A
Utilized by population 1
Compound B
Utilized by population 2
Compound C
utilized by both Population 1+2
Products
In this theoretical example of syntrophism, population 1 is able to utilize and metabolize compound A, forming compound B but cannot metabolize beyond compound B without co-operation of population 2. Population 2is unable to utilize compound A but it can metabolize compound B forming compound C. Then both population 1 and 2 are able to carry out metabolic reaction which leads to formation of end product that neither population could produce alone.
Examples of syntrophism:
i. Methanogenic ecosystem in sludge digester
Methane produced by methanogenic bacteria depends upon interspecies hydrogen transfer by other fermentative bacteria.
Anaerobic fermentative bacteria generate CO2 and H2 utilizing carbohydrates which is then utilized by methanogenic bacteria (Methanobacter) to produce methane.
ii. Lactobacillus arobinosus and Enterococcus faecalis:
In the minimal media, Lactobacillus arobinosus and Enterococcus faecalis are able to grow together but not alone.
The synergistic relationship between E. faecalis and L. arobinosus occurs in which E. faecalis require folic acid
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
CLASS 12th CHEMISTRY SOLID STATE ppt (Animated)eitps1506
Description:
Dive into the fascinating realm of solid-state physics with our meticulously crafted online PowerPoint presentation. This immersive educational resource offers a comprehensive exploration of the fundamental concepts, theories, and applications within the realm of solid-state physics.
From crystalline structures to semiconductor devices, this presentation delves into the intricate principles governing the behavior of solids, providing clear explanations and illustrative examples to enhance understanding. Whether you're a student delving into the subject for the first time or a seasoned researcher seeking to deepen your knowledge, our presentation offers valuable insights and in-depth analyses to cater to various levels of expertise.
Key topics covered include:
Crystal Structures: Unravel the mysteries of crystalline arrangements and their significance in determining material properties.
Band Theory: Explore the electronic band structure of solids and understand how it influences their conductive properties.
Semiconductor Physics: Delve into the behavior of semiconductors, including doping, carrier transport, and device applications.
Magnetic Properties: Investigate the magnetic behavior of solids, including ferromagnetism, antiferromagnetism, and ferrimagnetism.
Optical Properties: Examine the interaction of light with solids, including absorption, reflection, and transmission phenomena.
With visually engaging slides, informative content, and interactive elements, our online PowerPoint presentation serves as a valuable resource for students, educators, and enthusiasts alike, facilitating a deeper understanding of the captivating world of solid-state physics. Explore the intricacies of solid-state materials and unlock the secrets behind their remarkable properties with our comprehensive presentation.
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...Travis Hills MN
By harnessing the power of High Flux Vacuum Membrane Distillation, Travis Hills from MN envisions a future where clean and safe drinking water is accessible to all, regardless of geographical location or economic status.
Evidence of Jet Activity from the Secondary Black Hole in the OJ 287 Binary S...Sérgio Sacani
Wereport the study of a huge optical intraday flare on 2021 November 12 at 2 a.m. UT in the blazar OJ287. In the binary black hole model, it is associated with an impact of the secondary black hole on the accretion disk of the primary. Our multifrequency observing campaign was set up to search for such a signature of the impact based on a prediction made 8 yr earlier. The first I-band results of the flare have already been reported by Kishore et al. (2024). Here we combine these data with our monitoring in the R-band. There is a big change in the R–I spectral index by 1.0 ±0.1 between the normal background and the flare, suggesting a new component of radiation. The polarization variation during the rise of the flare suggests the same. The limits on the source size place it most reasonably in the jet of the secondary BH. We then ask why we have not seen this phenomenon before. We show that OJ287 was never before observed with sufficient sensitivity on the night when the flare should have happened according to the binary model. We also study the probability that this flare is just an oversized example of intraday variability using the Krakow data set of intense monitoring between 2015 and 2023. We find that the occurrence of a flare of this size and rapidity is unlikely. In machine-readable Tables 1 and 2, we give the full orbit-linked historical light curve of OJ287 as well as the dense monitoring sample of Krakow.
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...Sérgio Sacani
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS
+
53.13485
−
27.82088
with a host spectroscopic redshift of
2.903
±
0.007
. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (
�
(
�
−
�
)
∼
0.9
) despite a host galaxy with low-extinction and has a high Ca II velocity (
19
,
000
±
2
,
000
km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-
�
Ca-rich population. Although such an object is too red for any low-
�
cosmological sample, we apply a fiducial standardization approach to SN 2023adsy and find that the SN 2023adsy luminosity distance measurement is in excellent agreement (
≲
1
�
) with
Λ
CDM. Therefore unlike low-
�
Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-
�
truly diverge from their low-
�
counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
_Extraction of Ethylene oxide and 2-Chloroethanol from alternate matrices Li...LucyHearn1
How do you know your food is safe?
Last Friday was world World Food Safety Day, facilitated by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) in which the slogan rightly says, 'food safety is everyone's business'. Due to this, I thought it would be worth sharing some data that I have worked on in this field!
Working at Markes International has really opened my eyes (and unfortunately my friends and family 🤣) to food safety and quality, especially with my recent application work on ethylene oxide and 2-chloroethanol residues in foodstuffs, as of the biggest global food recalls in history was and is still being implemented by the Rapid alert system for food and feed (RASFF) in 2021, for high levels of these carcinogenic compounds.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
SDSS1335+0728: The awakening of a ∼ 106M⊙ black hole⋆Sérgio Sacani
Context. The early-type galaxy SDSS J133519.91+072807.4 (hereafter SDSS1335+0728), which had exhibited no prior optical variations during the preceding two decades, began showing significant nuclear variability in the Zwicky Transient Facility (ZTF) alert stream from December 2019 (as ZTF19acnskyy). This variability behaviour, coupled with the host-galaxy properties, suggests that SDSS1335+0728 hosts a ∼ 106M⊙ black hole (BH) that is currently in the process of ‘turning on’. Aims. We present a multi-wavelength photometric analysis and spectroscopic follow-up performed with the aim of better understanding the origin of the nuclear variations detected in SDSS1335+0728. Methods. We used archival photometry (from WISE, 2MASS, SDSS, GALEX, eROSITA) and spectroscopic data (from SDSS and LAMOST) to study the state of SDSS1335+0728 prior to December 2019, and new observations from Swift, SOAR/Goodman, VLT/X-shooter, and Keck/LRIS taken after its turn-on to characterise its current state. We analysed the variability of SDSS1335+0728 in the X-ray/UV/optical/mid-infrared range, modelled its spectral energy distribution prior to and after December 2019, and studied the evolution of its UV/optical spectra. Results. From our multi-wavelength photometric analysis, we find that: (a) since 2021, the UV flux (from Swift/UVOT observations) is four times brighter than the flux reported by GALEX in 2004; (b) since June 2022, the mid-infrared flux has risen more than two times, and the W1−W2 WISE colour has become redder; and (c) since February 2024, the source has begun showing X-ray emission. From our spectroscopic follow-up, we see that (i) the narrow emission line ratios are now consistent with a more energetic ionising continuum; (ii) broad emission lines are not detected; and (iii) the [OIII] line increased its flux ∼ 3.6 years after the first ZTF alert, which implies a relatively compact narrow-line-emitting region. Conclusions. We conclude that the variations observed in SDSS1335+0728 could be either explained by a ∼ 106M⊙ AGN that is just turning on or by an exotic tidal disruption event (TDE). If the former is true, SDSS1335+0728 is one of the strongest cases of an AGNobserved in the process of activating. If the latter were found to be the case, it would correspond to the longest and faintest TDE ever observed (or another class of still unknown nuclear transient). Future observations of SDSS1335+0728 are crucial to further understand its behaviour. Key words. galaxies: active– accretion, accretion discs– galaxies: individual: SDSS J133519.91+072807.4
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSSérgio Sacani
The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
Surface Polaritons in GAAS/ALGAAS/LH Hetrojunction Structure in a High Magnetic Field
1. International Journal of Recent advances in Physics (IJRAP) Vol.4, No.4, November 2015
DOI : 10.14810/ijrap.2015.4402 15
SURFACE POLARITONS IN GAAS/ALGAAS/LH
HETROJUNCTION STRUCTURE IN A HIGH
MAGNETIC FIELD
Majdi S. Hamada1
, Ali. H. EL-Astal1
and Mohamed. M. Shabat2
1
Department of Physics, Al-Aqsa University, Gaza, P.O. Box 4015,
Gaza Strip, Palestinian Authority
2
Department of Physics, The Islamic University of Gaza, P.O. Box 108, Gaza Strip,
Palestinian Authority
ABSTRACT
The surface polaritons (SP) variation in Ga As/ Al Ga As/ LH hetrojunction composition in the presence of
a strong transverse quantized magnetic field is estimated using the quantum Hall effect case. The
dispersion characteristics of the SPs are investigated using the dielectric constants values of the Ga As and
the Alx Ga 1-x As media and the defined thickness, the Alx Ga 1-x As medium. The dispersion behaviours
calculated results are listed for considered cases. It was shown that the frequency values against the wave
vector values are affected in a strong manner by changing thickness, of the Alx Ga 1-x- As media and by
changing the variation of the dielectric constants of Ga As against the Alx Ga 1-x As. The significance
effects of the use of the left-handed (LH) medium as an upper layer of the proposed composition was
demonstrated; the frequency values are remarkably increased using LH material as an upper layer. It was
noticed that at certain conditions of the LH upper layer composition, similar results have been obtained
such as found by using dielectric upper layer.
KEYWORDS
Dispersion relation, Surface Polaritons, Left-Handed Material, Hetrojunction Structure
1. INTRODUCTION
According to rapid advance in crystal-growth procedures, such as molecular beam epitaxy and
metal-organic chemical vapour deposition, the importance of the collective electromagnetic
excitation in two-dimensional electron systems (2DES) has been strongly enhanced. This leads to
the special interest in the surface polaritons (SP) which are non- irradiate electromagnetic waves
existed at the 2DES [1-3].
When an external magnetic field B is applied, (in such a way which is perpendicular to the 2DES)
leads to important characteristics. For instance, the phase velocity k
ph /
ω
ν = , and the group
velocity, k
g ∂
∂
= /
ω
ν , of the SPs decrease remarkably in the neighborhood of the cyclotron
resonance (CR). ω and k are the frequency and the in-plane value of the wave vector of the SPs,
respectively [4]. In this case, the SPs become slow waves. Of great importance are the
characteristics of the SPs in high values of magnetic fields, under the conditions which produce
the integer quantum Hall effect [5,6]. In this case, all of the values of the conductivity tensor of
the 2DES are quantized, i.e. they exhibit stepwise behavior as the magnetic field varies. Due to
this, the dispersion behaviors of the SPs are quantized too. Specially, when the magnetic field
value is varied, the SP group velocity is demonstrated in a quantized variation in the
2. International Journal of Recent advances in Physics (IJRAP) Vol.4, No.4, November 2015
16
neighborhood of the CR. The value of the steps is proportional to the fine-structure constant,
c
e h
/
2
=
α , where e is the electron charge, and c is the velocity of light.
It is considered here that the dispersion characteristics of the SPs are studied in such a case which
is assumed that a 2DES is positioned into an infinite homogeneous medium where dielectric
constant is ε [5,6]. In fact, the real picture is more complicated. A chosen doped AlxGa 1-xAs
medium has a finite thickness. This leads to the fact the electrons which form the 2DES are
positioned between a GaAs medium (this layer forms the substrate, and its thickness can be
considered to be infinite) and a AlxGa1-xAs medium. Furthermore, the dielectric constants of
GaAs and AlxGa 1-xAs are not the same [7,8]. In [7,8] the ratio of the dielectric constants of the
AlxGa1-xAs and the GaAs was chosen to be 0.95. These parameters select the behavior of the SPs
in the GaAs/ AlxGa1-xAs structure.
In these days, negative refraction in left-handed materials (LHMs) encourage researchers for high
concern, giving an excellent picture for research in both theoretical and practical fields. More
than six decades ago, the theory of the propagation of electromagnetic waves in such media
developed by Veselago [9]. Pendry et. al. [10,11] triggered the beginning of such important field,
this encouraged construction of the earlier LHM structure. His research group conducted many
valuable experiments, in the microwave radiation. This research team used a structure of split-
ring resonators (SRRs) of metal. This SRRs have certain useful properties in selected conditioned
preferred in the world of electronics and industry where the working medium has outstanding
amazed feature, i.e., negative permeability µ [10]. Thin wires of metal was constructed in a way
similar to a quasi-metal where it has a negative permittivity ε at microwave radiation [11,12].
Smith et. al. [13] constructed, a left-handed materials where both ε and µ have negative values in
preferable radiation condition. Although the fact that many researchers concentrated on the study
and investigation of LHM. |There still many things are not well known [14-18]. The researchers
give the important beginning of the study of both the theory and practice side of the topic. Thus
surface polariton of a LHM [19], highlighting the characteristics of LHM spheres [20] or
cylinders [21], or the characteristics of radiation propagation in LHM [22] are studied in the
theory side, and in the practice concern [13,23].
In this paper, we investigate the surface polaritons in a 2DES where the quantum Hall effect is
applied, and where also the finite thickness of the AlxGa 1-x As medium and taking into
consideration the great difference of the dielectric constants of GaAs and AlxGa 1-xAs. Because
of the interested characteristics of LHM [24-28], we introduce a LHM upper layer in the proposed
structure and study the characteristics of surface polaritons in GaAs/ AlGaAs/ LHM
hetrojunction in a high magnetic field structure as shown in figure 1.
3. International Journal of Recent advances in Physics (IJRAP) Vol.4, No.4, November 2015
17
.
2. THEORY: ELECTOMAGNETIC OF THE GaAs/ AlGaAs
HETROJUNCTION IN A HIGH MAGNETIC FIELD
Fig.1. shows our model structure, it consists of two semi-infinite media, with medium1 is LHM
and dielectric constant ε1 (z > d) and medium3 (z < 0), with dielectric constant ε3, separated by
a thin layer (medium 2) with the thickness d and the dielectric constant ε2. Medium 2 is consists
of AlGaAs semiconductor and medium 3 is also of GaAs semiconductor and these two mediums
form the hetrojunction at the interface z = 0, i.e. 2DES is formed. The external quantized
magnetic field, B, is directed perpendicularly along z-axis. The components of the
electromagnetic fields are considered to be non-irradiative, so the propagation of the SPs in a
2DES in the media 1 and 3 were decreased exponentially as the distance |z| → ∞.
To derive the dispersion equation which describe the SPs, two type of waves, TE and TM waves
are taken into account, where the surface current is presented at the interface z = 0,which make
TE and TM waves are mixed[29].
We assume that the electromagnetic waves are propagating along the x-axis, and the components
of TM waves in each media, 1,2,3, have
Hy,1 = H1 exp[i(kx – ωt) – p1(z – d)] z > d (1)
Ex,1 = (icp / ωε1 ) Hy,1 z > d (2)
Ez,1 = – (ck / ωε1 ) Hy,1 z > d (3)
z
d
0 2DES
x
Fig.1: The geometry of the proposed structure. The
semi-infinite medium 1 is the left-hand material layer
with ε1 and µ1; medium 2 is the AlxGa1-x As layer
with the dielectric constant ε2 ; the semi-infinite
medium 3 is the GaAs layer with the dielectric
constant ε .
4. International Journal of Recent advances in Physics (IJRAP) Vol.4, No.4, November 2015
18
)]
(
exp[
)]
exp(
)
exp(
[ 2
)
2
(
2
2
)
1
(
2
2
, t
kx
i
z
p
H
z
p
H
H y ω
−
−
+
= 0 < z < d (4)
Ex,2 = – (ck / ωε2 ) )
/
( 2
, z
H y ∂
∂ (5)
Ez,2 = – (ck / ωε2 ) Hy,2 (6)
Hy,3 = H3 exp[i (kx – ωt) + p3z] z < 0 (7)
3
,
3
3
3
, )
/
( y
x H
icp
E ε
ω
−
= (8)
Ez,3 = (- ck / ωε3 ) Hy,3 (9)
2
2
2
0 1,2, 3
y x z i i i
E H H p k i
c
ω
ε µ
= = = = − = , and 2 3 1
µ µ
= = .
In the case of non-radiative waves, the condition for the component of the wave vector k should
hold:
Re .
3
,
1
0 =
i
pi f (10)
The components of the electromagnetic field for the non-radiative TE waves have the form
Ey,1 = E1 exp[i(kx – ωt) – p1(z – d)] z > d (11)
Hx,1 = - I (cp1 / ω µ1 ) Ey,1 (12)
Hz,1 = (ck / ω µ1 ) Ey,1 (13)
)]
(
exp[
)]
exp(
)
exp(
[ 2
)
2
(
2
2
)
1
(
2
2
, t
kx
i
z
p
E
z
p
E
Ey ω
−
−
+
= 0<z < d (14)
Hx,2 = (ic / ω) )
/
( 2
, z
Ey ∂
∂ (15)
5. International Journal of Recent advances in Physics (IJRAP) Vol.4, No.4, November 2015
19
Hz,2 = (ck / ω) Ey,2 (16)
Ey,3 = E3 exp[i (kx – ωt) + p3z] z < 0 (17)
3
,
3
3
, )
/
( y
x E
icp
H ω
= (18)
Hz,3 = (ck / ω) Ey,3 (19)
Hy = Ex = Ez = 0
By taking the boundary conditions at the interface z = d, and the presence of a surface current at
the interface z = 0 leads to discontinuity of the magnetic field tangential components giving the
following equations:
)
(
)
(
)
(
3
,
)
(
2
, (
4 s
x
xy
s
y
xx
s
x
s
x E
E
c
H
H σ
σ
π
−
=
− (20)
)
(
)
(
)
(
3
,
)
(
2
, (
4 s
y
xy
s
x
xx
s
y
s
y E
E
c
H
H σ
σ
π
−
=
− (21)
where, )
(ω
σ ij are the 2DES conductivity tensor components, and the index s indicates the values
of the electric and magnetic fields at the interface z = 0. We assume that the spatial dispersion of
the conductivity tensor can be neglected, i.e. 1
pp
kl , where 2
/
1
)
/
( B
e
h
c
l = is the magnetic
length [5, 6]:
2
2
1
2
γ
γ
σ
+
=
N
h
e
xx (22)
2
2
1
2
γ
σ
+
=
N
h
e
xy (23)
where Ω
−
= /
)
( ω
ν
γ i , and mc
B
e /
=
Ω is the cyclotron frequency; ν is the momentum
relaxation frequency of the electrons; and n
l
N 2
π
= is the Landau-level filling factor and has an
integer values (N = 1,2,….) which equal to the numbers of filled Landau levels lying below the
Fermi level.
By using the boundary conditions at the interfaces z = 0 and z = d, the dispersion equation of the
non-irradiative SPs can be derived:
0
)
/
4
( 2
1
3
2
2
2
1 =
+ B
B
p
p
c
A
A xy
πσ (24)
Where
6. International Journal of Recent advances in Physics (IJRAP) Vol.4, No.4, November 2015
20
)
(
))
/
4
(
(
)
2
(
exp
)
(
))
/
4
(
(
2
1
1
2
3
2
3
2
2
3
2
2
1
1
2
3
2
3
2
2
3
1
ε
ε
ω
σ
π
ε
ε
ε
ε
ω
σ
π
ε
ε
p
p
p
p
i
p
p
d
p
p
p
p
p
i
p
p
A
xx
xx
+
+
+
+
−
−
−
=
(25)
2
2 2 3 1 2 1
2
2 2 3 1 2 1
( ( 4 / ))( )
exp(2 )( ( 4 / ))( )
xx
xx
A p p i c p p
p d p p i c p p
π ωσ µ
π ωσ µ
= − + − −
+ − +
(26)
1 1 2 1 2 1 2 1
- exp(2 )( )
B p p p d p p
µ µ
= + + (27)
)
(
)
2
(
exp
- 1
2
1
2
2
1
1
2
2 2
ε
ε
ε ε p
p
d
p
p
p
B +
+
= (28)
In our study, we take the dimensionless frequency ξ = ω /Ω, the dimensionless wave vector ζ = ck
/Ω, and the dimensionless thickness δ = dΩ/c. It was published [30] that when considering the
limiting cases in which the 2DES is located between the two-infinite media, i.e. δ = ∞ and δ = 0.
The dispersion curves ξ (ζ) for Surface Polaritons (SP) were shown for two cases: layer 1 is a
dielectric (a vacuum or an air) where ε1 = 1 while ε2 = 12.0 and ε3 = 12.9. The numbers 1 and 5
indicate the values of N considered in our analysis and the finite value of the dimensionless
thickness δ = 0.7. It was found [10] that the dispersion curves for the case where ε2 = ε3 = 12, δ
= ∞, the point at which dispersion curves intersect, ζ∞ = ck∞ / Ω, is located to the right of the one
obtained when δ = 0. In the case where δ = ∞, the larger value of the dielectric constant of GaAs
substrate (in comparison with the dielectric constant of AlxGa1-xAs) leads to decrease of the
phase and the group velocities of the SPs in the vicinity of the CR. If δ decrease, the phase and
the group velocities of the SPs increase and they reach maximum values at δ = 0. The difference
between the dielectric constants of two media, 2 and 3, leads to an interesting new results, i.e., all
dispersion curves start at the light line for the GaAs medium.
3. RESULTS AND DISCUSSIONS
In the calculation, several sets of 1
ε and 1
µ of the LH material are considered with their products
kept the same i.e., 1 1 4
ε µ = as shown in table 1[30]. In figure 2, the dispersion curves for the SP
are presented where the dimensionless frequency is plotted against the dimensionless wave
vector. In figure 2 (a) the upper layer of the structure is considered to a vacuum or an air
(dielectric), i.e. ε1 = 1 as published before [31] while in figure 2 (b) a Left Handed (LH) material
is introduced as an upper layer where ε1 = -2, µ1 = -2 , while ε2 = 12.0 and ε3 = 12.5 . This has
been conducted to compare between our current structure presented in this work and similar
structure published before. The only difference between the two structures is the replacement of
the upper layer to be a LH material rather than a dielectric in previous work. Figure 2 (a) and (b)
had been computed for the definite values of the dimensionless thickness δ = 0.65 and for the
values of the Landen level filling N = 1 ( solid) line, N=5 (dotted line) and N=10 (dashed line). It
can be seen from figure 2 (a) that the intersection point in all curves is (5, 1) and the change of the
frequency versus wave vector is more pronounced with increasing of N; there is very slight
difference of the values of the frequency with the change of the wave vector at N = 5. In Figure 2
(b) it is obvious the effect of introducing the LH upper layer. At wave number values less than 5
it can be seen the rapid increase of the operating frequency versus the increase of wave number.
At wave number of 5 the frequency equals 1.22. This is the benefit of the LH layer. At wave
number is more than 5 the behavior of the frequency versus wave number is very similar to the
traditional structure where the upper layer is dielectric.
7. International Journal of Recent advances in Physics (IJRAP) Vol.4, No.4, November 2015
21
Different situation is there in figure 3 where the dispersion curves for the SPs is presented as ε2
and ε3 were kept equals and have the values of 12.0, for two values of the dimensionless
thickness: δ = 0.1 for the dashed line and δ = 1 for the solid line and for unique value of N = 1.
It can be noticed from the figure that the frequency has a cut off at wave number = 4.9 for δ = 1
and a wave vector = 5.85 for δ = 0.1, similar to the above case as shown in figure 2. In both
cases the frequency starts to appear again directly after the cut off value of the wavenumber but
with very lower value nearly equals 1 . In the dashed line and with decreasing the thickness of
factor of ten, it is shown that the rapid increase of frequency versus wave vector continues up to
wave vector of 5.85. This shows the importance of the decrease of the thickness of LH material
upper layer in the performance of the structure. Moreover it is noticed that a higher value of
frequency of 1.4 can be obtained at a wave vector = 5.85.
Table 1
Combination of 1
ε and 1
µ of LH material in the present study
1
ε 1
µ
-8 -0.5
-5 -0.8
-0.5 -8
-2 -2
-1 -4
-0.8 -5
8. International Journal of Recent advances in Physics (IJRAP) Vol.4, No.4, November 2015
22
Fig. 3. The dispersion curves for the SPs in the case in which ε1 = -2, µ1 =
-2, ε2 = 12.0, ε3 = 12.0, and for the finite values of the dimensionless
thickness δ = 0.1 (dashed line) and δ = 1 (solid line) and for N =1. (b) and
(c) is (a) but split in two figures and magnified to highlight the curves.
ξ=ω/Ω
=ck/Ω
ζ
(a
ξ=ω/Ω
ξ=ω/Ω
=ck/Ω
ζ
=ck/Ω
ζ
(b) (c)
9. International Journal of Recent advances in Physics (IJRAP) Vol.4, No.4, November 2015
23
In figure 4 the dispersion curves for the SPs is presented where ε2 = 12.0 and ε3 = 12.9, i.e. they
are not equal as in figure 3, while for the same two values of the dimensionless thickness used in
figure 3: δ = 0.1 for the dashed line and δ = 1 for the solid line and also for unique value of N= 1
used in figure 3.
It can be observed from the figure 4 that the frequency has a cut off at wave vector = 5 for δ = 1
and a wave vector = 6 for δ = 0.1. It is clear that there is slightly increase of the wave vector
values of the cut off when ε3 is slightly increased from ε2 = 12.0 (figure 3) to ε3 = 12.9 (figure 4).
It is also noticed that there is slightly increase of the frequency values of the cut off from 1.18 (at
ε2 = 12.0) to 1.22 (ε3 = 12.9) in the solid line (δ = 1).
Different situation is considered in figure 5 where the curves are plotted in different manner. In
the previous figures 2,3,4: ε1 and µ1 are fixed and both kept equal -2, and the variation is in the
other parameters, i.e., ε2, ε3 and the dimensionless thickness δ. Here in figure 5: ε2 and ε3 were
fixed and kept equal 12 and the dimensionless thickness δ is also fixed while ε1 and µLH were
varied and have different values. As can be seen in figure 5 (a), four curves are plotted where all
the curves have the same behavior and looks parallel. The frequency is higher and more
pronounced ( Maximum frequency = 1.4) in curve 4 where ε1 has the highest value = - 0.5 while
µ1 has the lowest value = -8. The lowest frequency (Maximum frequency = 1.18) is obtained in
curve 1 where ε1 =-2 and µ1=-2. This data show the sensitivity and importance influence of the
left- handed layer's parameters upon the value of the obtained frequency which should be
considered in the proposed structure. It is also noticed in figure 5(b) that despite the variation in
Fig. 4. The dispersion curves for the SPs in the case in which ε1 = -2, µ1 = -2, ε2 = 12.0, ε3
= 12.9, and for the finite values of the dimensionless thickness δ = 0.1 (dashed line) and δ
= 1 (solid line) and for N =1. (b) and (c) is (a) but split in two figures and magnified to
highlight the curves.
ξ=ω/Ω
=ck/Ω
ζ
ξ=ω/Ω
ξ=ω/Ω
=ck/Ω
ζ =ck/Ω
ζ
(a)
(b) (c)
10. International Journal of Recent advances in Physics (IJRAP) Vol.4, No.4, November 2015
24
the lift- handed layer's parameters the cut off in the four curves occur at the same wave vector
value.
In figure 5 (b) very low values of ε1 are chosen: ε1 = - 8 (case 1) and ε1 = - 5 (case 2) whereas
high values of µ were considered: µ1 = - 0.5 (case 1) and µ1 = - 0.8 (case 2). In this case very
nice results have been noticed; two intersected curves were seen using ( N =1 and N =2 ). The
features of these curves which obtained with left-handed material upper layer of the structure are
similar to the results ( which presented in figure 2(a) )obtained using dielectric (vacuum) upper
layer.
4. CONCLUSIONS
We have calculated the spectrum of the SPs in the GaAs/AlxGa1-x As/LH heterojunction in a high
magnetic field, i.e. for a case in which the effects of quantization of the conductivity tensor of a
2DES are crucial. It is shown that all of the dispersion characteristics of the SPs under the
conditions of the integer quantum Hall effect are quantized. In the vicinity of the cyclotron
resonance, the phase and group velocities of the SPs are decreasing significantly.
The values of the dimensionless frequency versus dimensionless wave vector of the SPs can
strongly effected by using the LH upper layer in the proposed structure. These values are also
influenced with increasing thickness d of the Alx Ga 1-x As layer, and with the variation of the
difference between the dielectric constants of GaAs and Alx Ga 1-x As. This fact can be used in
various applications in microelectronics and in making contactless measurements of the
parameters of GaAs/AlxGa1-x As/LH heterojunction. Investigations of the SPs using inelastic
light scattering are of important application for measuring the Landau-level filling factor N
dependence by using dispersion data with no direct contact with the GaAs/AlxGa1-x As/LH
heterojunction.
ACKNOWLEDGEMENTS
One of the Authors (M.M.S) gratefully acknowledge financial grant from the Alexander von
Humboldt Foundation and the hospitality of Prof. D.Schadaat, at the Clausthal University of
Technology, Germany
ξ=ω/Ω
ξ=ω/Ω
=ck/Ω
ζ
=ck/Ω
ζ
Fig. 5 The dispersion curves for the SPs in the case in which ε2 = 12.0, ε3 = 12, and for the
finite values of the dimensionless thickness δ =1 in the case (a) 1(ε1 = -2, µ1 = -2), 2 (ε1 = -1,
µ1 = -4), 3(ε1 = -0.8, µ1 = -5), 4(ε1 = -0.5, µ1 = -8), (b) in the case:1(ε1 = -8, µ1 = -0.5), 2 (ε1 = -
5, µ1 = -0.8),
(a) (b)
1
2
3
4
N=1
N=5
11. International Journal of Recent advances in Physics (IJRAP) Vol.4, No.4, November 2015
25
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