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Academic literature on the topic 'Cosmic Membrane Theory (CM)'
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Journal articles on the topic "Cosmic Membrane Theory (CM)"
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Stefan, von Weber, and von Eye Alexander. "Two-way and One-way Vacuum Speed of Light under the Membrane Paradigm." Physical Science International Journal 15, no. 2 (2017): 1–17. https://doi.org/10.9734/PSIJ/2017/32988.
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The discovery of cosmic microwave background radiation (CMB) by Wilson and Penzias defines a rest frame in the sense of Newton’s absolute space. This fact is one of the reasons why brane worlds moved into the focus of interest. Membrane theory (CM) uses the cosmological model of a 4-dimensional thin membrane, expanding in hyperspace. A homogeneous vector field acts perpendicularly from outside onto the membrane and causes, this way, curvature of space and gravitation. The membrane defines an absolute Newtonian space, and forces small changes of Special Relativity (SR). The most important difference between CM and SR is the introduction of a cross contraction of moving bodies. Photons travel always and only in the rest inertial reference frame. There is no difference between two-way and one-way speed of light. Far away from masses photons move with constant speed <em>c</em>. The rest inertial reference frame is defined by the absence of the dipole of the cosmic microwave background radiation (CMB), caused by the Doppler-effect. The speed of light is anisotropic in each inertial reference frame that is in relative motion with respect to the rest frame. Although the speed of light is constant in the vacuum, it can be measured on Earth only with a systematic error of ± 36.9 m/s. The reason is that the flow of time of the clocks on the Earth is not constant. The measurement of the one-way speed of light is a special issue. Although the speed of light is anisotropic in each moving inertial reference frame, the time transformation hides this fact nearly perfectly. A co-moving observer registers the arrival of the light signal after a time interval which suggests that speed of light is always <em>c</em>. To obtain this result, it is sufficient to accept the existence of a rest inertial reference frame and the transformation of time given by FitzGerald and Lorentz.
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Mesinger, Andrei. "Reionization and Cosmic Dawn: theory and simulations." Proceedings of the International Astronomical Union 12, S333 (2017): 3–11. http://dx.doi.org/10.1017/s1743921317011139.
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AbstractWe highlight recent progress in the sophistication and diversification of the simulations of cosmic dawn and reionization. The application of these modeling tools to recent observations has allowed us narrow down the timing of reionization. The midpoint of reionization is constrained to z = 7.6−0.7+0.8 (1 σ), with the strongest constraints coming from the optical depth to the CMB measured with the Planck satellite and the first detection of ongoing reionization from the spectra of the z = 7.1 QSOs ULASJ1120+0641. However, we still know virtually nothing about the astrophysical sources during the first billion years. The revolution in our understanding will be led by upcoming interferometric observations of the cosmic 21-cm signal. The properties of the sources and sinks of UV and X-ray photons are encoded in the 3D patterns of the signal. The development of Bayesian parameter recovery techniques, which tap into the wealth of the 21-cm signal, will soon usher in an era of precision astrophysical cosmology.
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Zeeshan, Muhammad, M. Zubair, and Rabia Saleem. "Role of collisional matter in the framework of extended teleparallel theory." International Journal of Modern Physics D 29, no. 15 (2020): 2050099. http://dx.doi.org/10.1142/s0218271820500996.
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The purpose of this work is to examine the cosmic evolution in the presence of collisional matter (CM) with and without radiations in a modified Teleparallel theory involving a generic function [Formula: see text] which depends on the scalar torsion [Formula: see text] and the boundary term associated to the divergence of torsion [Formula: see text]. We select seven novel [Formula: see text] models including power law, logarithmic models and exponential models, some of these reported in [S. Bahamonde, M. Zubair and G. Abbas, Phys. Dark Univ. 19 (2018) 78; S. Bahamonde and S. Capozziello, The Eur. Phys. J. C. 77 (2017) 107; C. Escamilla-Rivera and J. L. Said, Class. Quantum Grav. 37 (2020) 165002] and discuss the evolutionary scenario. The behavior of deceleration parameter [Formula: see text], Hubble parameter [Formula: see text], Equation-of-state (EoS) for dark energy (DE) and effective EoS is presented. [Formula: see text]CDM epoch and crossing of phantom divide line (approaching to phantom era) is observed in scenarios like noncollisional matter (NCM) with radiation, CM with and without radiation. Results are found to be adequate with recent cosmic observations.
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FUJISHIRO, TAKEHIKO T., MITSUO J. HAYASHI, and SHOJI TAKESHITA. "THE COSMIC STRINGS GENERATED FROM THE TORSION." Modern Physics Letters A 08, no. 06 (1993): 491–501. http://dx.doi.org/10.1142/s0217732393000519.
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The cosmic strings can be described naturally by torsion formalism which has a direct analogy with dislocations in three-dimensional crystalline solid. We have obtained an exact solution in a four-dimensional model on M2×T2 and may be expected to describe a space-time structure of our universe. The relation between the mass per unit length and the deficit angle are different from that of the Einstein theory, but can be made consistent since our model could reproduce its prediction. We could also obtain the maximum value of the mass per unit length µ~10−6(~1022 g/cm ) by fine tuning of a parameter, which is consistent with the recent observations.
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FUJISHIRO, TAKEHIKO T., MITSUO J. HAYASHI, and SHOJI TAKESHITA. "EXACT COSMIC STRING SOLUTIONS BASED ON THE CONTINUUM THEORY OF DISLOCATIONS." International Journal of Modern Physics A 09, no. 23 (1994): 4101–27. http://dx.doi.org/10.1142/s0217751x94001667.
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The effective action from the string compactification is studied on the manifolds with absolute parallelism. The cosmic strings can be described naturally by torsion formalism which has a direct analogy with dislocations in three-dimensional crystalline solids. We have found a stringy solution in a six-dimensional model on M4 × T2 which is compatible with that of Greene et al. and a cylindrically symmetric exact solution is obtained, which are different from the exact cosmic string solutions of the Einstein theory ever proposed. We have also obtained an exact solution in a four-dimensional model on M2 × T2 which can be considered as an example of the compactification on the noncompact manifold and may be expected to describe a space–time structure of our universe. The relation between the mass per unit length and the deficit angle is different from but can be consistent with that of the Einstein theory, since our solution could reproduce its prediction with a condition. We could also obtain the maximum value of the mass per unit length μ ~ 10−6 (~ 1022 g/cm ) by fine-tuning a parameter, which is consistent with recent observations. We have discussed the cosmic strings with the deficit angle larger than 2π.
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Wandel, Amri. "Supernova Remnants and the ISM: Constraints from Cosmic-Ray Acceleration." International Astronomical Union Colloquium 101 (1988): 325–29. http://dx.doi.org/10.1017/s0252921100102581.
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AbstractSupernova remnants can reaccelerate cosmic rays and modify their distribution during the cosmic ray propagation in the galaxy. Cosmic ray observations (in particular the boron-to-carbon data) strongly limit the permitted amount of reacceleration, which is used to set an upper limit on the expansion of supernova remnants, and a lower limit on the effective density of the ISM swept up by supernova shocks. The constraint depends on the theory of cosmic ray propagation: the standard Leaky Box model requires a high effective density, > 1cm−3, and is probably inconsistent with the present picture of the ISM. Modifying the Leaky Box model to include a moderate amount of weak-shock reacceleration, a self consistent solution is found, where the effective density in this solution is ≈ 0.1 cm−3, which implies efficient evaporation of the warm ISM component by young supernova remnants, during most of their supersonic expansion.
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Karaçaylı, Naim Göksel, and Nikhil Padmanabhan. "Anatomy of cosmic tidal reconstruction." Monthly Notices of the Royal Astronomical Society 486, no. 3 (2019): 3864–73. http://dx.doi.org/10.1093/mnras/stz964.
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Abstract 21-cm intensity surveys aim to map neutral hydrogen atoms in the universe through hyper-fine emission. Unfortunately, long-wavelength (low-wavenumber) radial modes are highly contaminated by smooth astrophysical foregrounds that are six orders of magnitude brighter than the cosmological signal. This contamination also leaks into higher radial and angular wavenumber modes and forms a foreground wedge. Cosmic tidal reconstruction aims to extract the large-scale signal from anisotropic features in the local small-scale power spectrum through non-linear tidal interactions; losing small-scale modes to foreground wedge will impair its performance. In this paper, we review tidal interaction theory and estimator construction, and derive the theoretical expressions for the reconstructed spectra. We show the reconstruction is robust against peculiar velocities. Removing low line-of-sight k modes, we demonstrate cross-correlation coefficient r is greater than 0.7 on large scales (k ≲ 0.1 h Mpc−1) even with a cut-off value $k^c_{\Vert }=0.1$h Mpc−1. Discarding wedge modes yields 0.3 ≲ r ≲ 0.5 and completely removes the dependency on $k^c_{\Vert }$. Our theoretical predictions agree with these numerical simulations.
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Roque, I. L. V., W. J. Handley, and N. Razavi-Ghods. "Bayesian noise wave calibration for 21-cm global experiments." Monthly Notices of the Royal Astronomical Society 505, no. 2 (2021): 2638–46. http://dx.doi.org/10.1093/mnras/stab1453.
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ABSTRACT Detection of millikelvin-level signals from the ‘Cosmic Dawn’ requires an unprecedented level of sensitivity and systematic calibration. We report the theory behind a novel calibration algorithm developed from the formalism introduced by the EDGES collaboration for use in 21-cm experiments. Improvements over previous approaches are provided through the incorporation of a Bayesian framework and machine learning techniques such as the use of Bayesian evidence to determine the level of frequency variation of calibration parameters that is supported by the data, the consideration of correlation between calibration parameters when determining their values, and the use of a conjugate-prior based approach that results in a fast algorithm for application in the field. In self-consistency tests using empirical data models of varying complexity, our methodology is used to calibrate a 50 Ω ambient-temperature load. The RMS error between the calibration solution and the measured temperature of the load is 8 mK, well within the 1 σ noise level. Whilst the methods described here are more applicable to global 21-cm experiments, they can easily be adapted and applied to other applications, including telescopes such as HERA and the SKA.
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KORNHUBER, M. E., and C. WALTHER. "The Electrical Constants of the Fibres from Two Leg Muscles of the Locust Schistocerca Gregaria." Journal of Experimental Biology 127, no. 1 (1987): 173–89. http://dx.doi.org/10.1242/jeb.127.1.173.
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1. The passive electrical properties of the fibres from the M. extensor tibiae and the M. retractor unguis in the hindleg of the locust Schistocerca gregaria were investigated using short cable theory. The dependence on various physicochemical parameters was determined. 2. The sarcoplasmic resistivity (R1) was the same in the extensor and in the retractor muscle. R1 was ≊ 175 Ωcm at 20°C. 3. The specific membrane resistance (Rm) was considerably lower in the retractor muscle (≊5100 Ωcm2) than in the extensor muscle (≊13 000 Ωcm2; [K+]o =; 10 mmoll−1; temperature = 20°C). Rm increased by more than 100 % if the external potassium concentration was lowered from 10 to 5 mmoll−1 and it decreased by approximately 75 % if the calcium concentration was lowered from 2 to 0.2 mmoll−1. 4. The specific membrane capacity (Cm) increased with fibre diameter. The different mean values for Cm in the extensor (8.5 μF cm−2) and retractor muscle (6.3 μF cm−2) can be accounted for by the different mean fibre diameters. 5. The temperature coefficients (Q10) of the electrical constants were 0.74 for Ri, 0.48 for Rm, 1.01 for Cm and 1.21 for the resting membrane potential (temperature, 16–27°C). 6. There was close agreement between the membrane time constant (τm) derived from the decay of the excitatory junction potential (EJP) and that derived from injection of current pulses. Thus Rm and the length constant (λ) can be derived from the EJP and the fibre diameter if the sarcoplasmic resistivity and the specific membrane capacity are known. 7. The temporospatial dependence of miniature EJPs in a fibre can be predicted satisfactorily from the electrical constants as is demonstrated by an example given in the Appendix. Note: Dedicated to the late Graham Hoyle
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Farinas, Javier, Malea Kneen, Megan Moore, and A. S. Verkman. "Plasma Membrane Water Permeability of Cultured Cells and Epithelia Measured by Light Microscopy with Spatial Filtering." Journal of General Physiology 110, no. 3 (1997): 283–96. http://dx.doi.org/10.1085/jgp.110.3.283.
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A method was developed to measure the osmotic water permeability (Pf) of plasma membranes in cell layers and applied to cells and epithelia expressing molecular water channels. It was found that the integrated intensity of monochromatic light in a phase contrast or dark field microscope was dependent on relative cell volume. For cells of different size and shape (Sf9, MDCK, CHO, A549, tracheal epithelia, BHK), increased cell volume was associated with decreased signal intensity; generally the signal decreased 10–20% for a twofold increase in cell volume. A theory relating signal intensity to relative cell volume was developed based on spatial filtering and changes in optical path length associated with cell volume changes. Theory predictions were confirmed by signal measurements of cell layers bathed in solutions of various osmolarities and refractive indices. The excellent signal-to-noise ratio of the transmitted light detection permitted measurement of cell volume changes of &lt;1%. The method was applied to characterize transfected cells and tissues that natively express water channels. Pf in control Chinese hamster ovary cells was low (0.0012 cm/s at 23°C) and increased more than fourfold upon stable transfection with aquaporins 1, 2, 4, or 5. Pf in apical and basolateral membranes in polarized epithelial cells grown on porous supports was measured. Pfbl and Pfap were 0.0011 and 0.0024 cm/s (MDCK cells), and 0.0039 and 0.0052 cm/s (human tracheal cells) at 23°C. In intact toad urinary bladder, basolateral Pf was 0.036 cm/s and apical membrane Pf after vasopressin stimulation was 0.025 cm/s at 23°C. The results establish light microscopy with spatial filtering as a technically simple and quantitative method to measure water permeability in cell layers and provide the first measurement of the apical and basolateral membrane permeabilities of several important epithelial cell types.
Conference papers on the topic "Cosmic Membrane Theory (CM)"
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Mi, Jia, Xian Wu, Joseph Capper, et al. "Modelling, Characterization and Testing of an Ocean Wave Powered Desalination System." In ASME 2022 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/detc2022-91285.
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Abstract Development of alternative freshwater via desalination can address water scarcity and security. Meanwhile, sustainable renewable energy sources are critical to economically achieve seawater desalination. Marine renewable energy has tremendous potential to power the blue economy and is co-located with seawater. This study proposes an ocean wave powered reverse osmosis desalination system, which consists of an oscillating surge wave energy converter with a piston pump and a reverse osmosis desalination module with an accumulator on the shore. Seawater can be pressurized by the oscillating surge wave energy converter and pumped to the reverse osmosis desalination module as feed where it then produces permeate that is free of undesired molecules and larger particles. Numerical models considering potential flow theory of the wave energy converter and solution-diffusion theory of the reverse osmosis membrane were established. A 1:10 scaled prototype was designed, fabricated and tested in a wave tank based on the Froude scaling law. Comprehensive wave tank tests were implemented, characterized, and analyzed considering the water-energy nexus. Scaled tests resulted in the minimal specific energy consumption of 0.44 kWh/m3 under regular wave (wave period Ts = 4s /wave height Hs = 10 cm) with the corresponding optimal recovery ratio of 32%.