Gravity Phenomena Research Articles

A simple but rigorous model for calculating CO2 storage capacity in deep saline aquifers at the basin scale

Safely sequestering CO2 in a deep saline aquifer requires calculating how much CO2 the aquifer can store. Since offsetting nationwide emissions requires sequestering large quantities of CO2, this calculation should apply at the large scale of geologic basins. The only method to calculate storage capacity at the basin scale, however, is not derived from multiphase flow dynamics, which play a critical role in CO2 storage. In this study, we explain a new model to calculate basin-scale storage capacity that is derived from flow dynamics and captures the dynamic phenomena of gravity override and capillary trapping. Despite the fact that the model is dynamic, it is simple since it is a closed form expression with few terms. We demonstrate how to apply it on the Fox Hills Sandstone in the Powder River Basin.

On Relativistic Generalization of Gravitational Force

In relativistic theories, the assumption of proper mass constancy generally holds. We study gravitational relativistic mechanics of point particle in the novel approach of proper mass varying under Minkowski force action. The motivation and objective of this work are twofold: first, to show how the gravitational force can be included in the Special Relativity Mechanics framework, and, second, to investigate possible consequences of the revision of conventional proper mass concept (in particular, to clarify a proper mass role in the divergence problem). It is shown that photon motion in the gravitational field can be treated in terms of massless refracting medium, what makes the gravity phenomenon compatible with SR Mechanics framework in the variable proper mass approach. Specifically, the problem of point particle in the spherical symmetric stationary gravitational field is studied in SR-based Mechanics, and equations of motion in the Lorentz covariant form are obtained in the relativistic Lagrangean problem formulation. The dependence of proper mass on potential field strength is derived from the Euler-Lagrange equations as well. One of new results is the elimination of conventional 1/r divergence, which is known to be not removable in Schwarzschild gravitomechanics. Predictions of particle and photon gravitational properties are in agreement with GR classical tests under weak-field conditions; however, deviations rise with potential field strength. The conclusion is made that the approach of field-dependent proper mass is perspective for development of SR gravitational mechanics and further studies of gravitational problems.

Genesis and evolution of ‘pseudocarniole’: preliminary observations from the Susa Valley (Western Alps)

Abstract In the Alpine geological literature some particular carbonate rocks having a vuggy appearance, associated with evaporite rocks, have a controversial origin and diversified, uneven, nomenclature. In this paper they are provisionally called ‘pseudocarniole’. An excellent exposure along the Susa Valley (Italian Western Alps) permitted a relatively full analysis of a group of such vuggy rocks in situ . Five main lithologies have been identified with respect to their nature, shape, dimensions and organization of the clasts, also according to the matrix and the composition of the cements. Utilizing the interpretation of geological and geomorphological field data that cover these deposits, detailed stratigraphical descriptions and laboratory microanalyses (optical microscope and cathode-luminescence), a genetic interpretative model is proposed. The main formational process is dissolution, starting from solution of gypsum and anhydrite; then the processes affecting carbonate ‘parental residual rocks’ are considered. Thereafter a general instability of the rock masses is introduced with a consequent gravitational collapse. Other general processes are usually associated: tectonics, gravity and Plio-Quaternary karst phenomena. Finally, a particularly young age for the formation of the pseudocarniole deposits is noted, based on palynological data, Plio-Quaternary.

Entanglement entropy in critical phenomena and analog models of quantum gravity

A general geometrical structure of the entanglement entropy for spatial partition of a relativistic QFT system is established by using methods of the effective gravity action and the spectral geometry. A special attention is payed to the subleading terms in the entropy in different dimensions and to behavior in different states. It is conjectured, on the base of relation between the entropy and the action, that in a fundamental theory the ground state entanglement entropy per unit area equals $1/(4{G}_{N})$, where ${G}_{N}$ is the Newton constant in the low-energy gravity sector of the theory. The conjecture opens a new avenue in analogue gravity models. For instance, in higher-dimensional condensed matter systems, which near a critical point are described by relativistic QFT's, the entanglement entropy density defines an effective gravitational coupling. By studying the properties of this constant one can get new insights in quantum gravity phenomena, such as the universality of the low-energy physics, the renormalization group behavior of ${G}_{N}$, the statistical meaning of the Bekenstein-Hawking entropy.

Threshold effects and Planck scale Lorentz violation: Combined constraints from high energy astrophysics

Recent work has shown that dispersion relations with Planck scale Lorentz violation can produce observable effects at energies many orders of magnitude below the Planck energy M. This opens a window on physics that may reveal quantum gravity phenomena. It has already constrained the possibility of Planck scale Lorentz violation, which is suggested by some approaches to quantum gravity. In this work we carry out a systematic analysis of reaction thresholds, allowing unequal deformation parameters for different particle dispersion relations. The thresholds are found to have some unusual properties compared with standard ones, such as asymmetric momenta for pair creation and upper thresholds. The results are used together with high energy observational data to determine combined constraints. We focus on the case of photons and electrons, using vacuum \ifmmode \check{C}\else \v{C}\fi{}erenkov, photon decay, and photon annihilation processes to determine order unity constraints on the parameters controlling $O(E/M)$ Lorentz violation. Interesting constraints for protons (with photons or pions) are obtained even at $O({(E/M)}^{2}),$ using the absence of vacuum \ifmmode \check{C}\else \v{C}\fi{}erenkov and the observed GZK cutoff for ultrahigh energy cosmic rays. A strong \ifmmode \check{C}\else \v{C}\fi{}erenkov limit using atmospheric PeV neutrinos is possible for $O(E/M)$ deformations provided the rate is high enough. If detected, ultrahigh energy cosmological neutrinos might yield limits at or even beyond $O({(E/M)}^{2}).$

On time-dependent AdS/CFT

We clarify aspects of the holographic AdS/CFT correspondence that are typical of Lorentzian signature, to lay the foundation for a treatment of time-dependent gravity and conformal field theory phenomena. We provide a derivation of bulk-to-boundary propagators associated to advanced, retarded and Feynman bulk propagators, and provide a better understanding of the boundary conditions satisfied by the bulk fields at the horizon. We interpret the subleading behavior of the wavefunctions in terms of specific vacuum expectation values, and compute two-point functions in our framework. We connect our bulk methods to the closed time path formalism in the boundary field theory.

A spectral theory for small-amplitude miscible fingering

Using the self-similar symmetry of a diffusing front, we develop a linear spectral theory for miscible fingering at inception that accurately captures the destabilization of localized disturbances (with large transverse wavelengths compared to the front width) by the unsteady front. Our theory predicts a generic selected wavelength (4πηD/U0 for gravity fingering, where η is the transverse to longitudinal dispersion ratio, and an additional factor proportional to the logarithm of the mobility ratio for viscous fingering) at the small time of O(D/U02), where D is the dispersion coefficient or diffusivity in the flow direction and U0 is the displacement velocity. This wavelength then grows in time and approaches a universal asymptotic wavelength coarsening dynamics of (η2D5/U02)1/8(t′)3/8, where t′ is the dimensional time, for all small-amplitude miscible fingering phenomena in a slot or in porous media. The 38 exponent in time is due to a unique long-wave stabilization mechanism due to transverse convection, which escapes prior quasisteady theory. Explicit and generic scalings are then derived for gravity and viscous miscible fingering phenomena and are favorably compared to experimental and numerical results on linear coarsening dynamics.

Gravity as Spacetime Curvature

Einstein's general theory of relativity conceives the phenomena of gravity as manifestations of the curvature of the spacetime manifold in which physical events take place. I sketch the line of thought that led Einstein to this conception, and I briefly discuss proposals by Jeffreys and Feynman for retaining Einstein's gravitational field equations while discarding their purportedly geometrical meaning.

DIMENSIONFUL DEFORMATIONS OF POINCARÉ SYMMETRIES FOR A QUANTUM GRAVITY WITHOUT IDEAL OBSERVERS

Quantum mechanics is revisited as the appropriate theoretical framework for the description of the outcome of experiments that rely on the use of classical devices. In particular, it is emphasized that the limitations on the measurability of (pairs of conjugate) observables encoded in the formalism of quantum mechanics reproduce faithfully the "classical-device limit" of the corresponding limitations encountered in (real or gedanken) experimental setups. It is then argued that devices cannot behave classically in quantum gravity, and that this might raise serious problems for the search of a class of experiments described by theories obtained by "applying quantum mechanics to gravity." It is also observed that using heuristic/intuitive arguments based on the absence of classical devices one is led to consider some candidate quantum gravity phenomena involving dimensionful deformations of the Poincaré symmetries.

SEARCHING FOR QUANTUM GRAVITY EFFECTS IN COSMOLOGICAL DATA

If the inflationary scenario describes our Universe, then it is possible that quantum gravity phenomena could be observed in anisotropy experiments of the microwave background as well as in galaxy clustering data. Primordial gravitational radiation arising from inflation is a consequence of quantum gravity. Moreover, the wavefunction of the Universe is currently being measured by the COBE satellite. A non-Gaussian distribution could be a signature of nonlinear quantum gravity. In fact, the excess power power seen in the APM survey of galaxies can arise from non-Gaussian initial conditions generated during inflation.

Quantum gravity, random geometry and critical phenomena

We discuss the theory of non-critical strings with extrinsic curvature embedded in a target space dimensiond greater than one. We emphasize the analogy between 2d gravity coupled to matter and non self-avoiding liquid-like membranes with bending rigidity. We first outline the exact solution for strings in dimensionsd 1. Evidence from recent and ongoing numerical simulations of dynamically triangulated random surfaces indicate that there is a non-trivial crossover from a crumpled to an extended surface as the bending rigidity is increased. If the cross-over is a true second order phase transition corresponding to a critical point there is the exciting possibility of obtaining a well defined continuum string theory ford>1.

Gravity instabilities in magma chambers: rheological modelling

The physical study of gravity instabilities in magma chambers provides a method to estimate the rheological properties of magmas. Many layered intrusions exhibit gravity instability structures, such as magmatic load casts. We present here a study based on structures occuring in veined diorites in the layered plutonic complex of Guernsey. Wavelengths of gravitational perturbations are determined by spectral analysis. We relate the wavelengths to the rheological properties of the magmas by a perturbation enhancement model. The time scale for the gravity instabilities to develop is calculated to be about 10 2 s, which is about the characteristic time scale for solidification in these rocks; this is why these structures are preserved in the rock. The calculated length and time scales are compatible with the geometry of the observed structures and the crystallization kinetics of magma chambers, showing that the structures are appropriately modeled as gravity instabilities. This mechanical approach, together with petrological study and direct computation of magma viscosity, is likely to provide several constraints on petrogenetic modelling. The fact that the observed structures can be interpreted as gravity phenomena is clear evidence that the observed layering is a primary igneous feature rather than the result of any metasomatic process.

Ellipsometric Imaging of Drying Sol-Gel Films

ABSTRACTAlthough controlled dip-coating is an established way to apply high quality uniform coatings, the details of the coating and drying process have not been deeply studied. Depending on the physical and chemical state of the sol and the parameters of dipping (dipping angle and speed), a variety of thicknesses and porosities can be achieved [1]. For optical coatings, the refractive index and optical thickness can thereby be controlled.We have developed a method to view the drying front of a dip-coated film using broad beam ellipsometry [2], or “ellipsometric imaging.” In dip-coated films we take full advantage of the fact that a steady state is quickly reached where the drying line velocity matches the withdrawal velocity; however, the technique might also be used in unsteady situations such as spin coating. Imaging ellipsometry makes it possible to measure the refractive index and thickness profiles of both wet and dry films point-by-point in an entire image at once. These profiles provide important clues as to the relative importance of gravity, evaporation and other phenomena.

A study on polymer blending microrheology: Part IV. The influence of coalescence on blend morphology origination

AbstractThe influence of shear induced coalescence on the origination of morphologies in polymer blending processes is investigated both theoretically and experimentally. In the theoretical part a route is proposed to estimate the fraction of collisions between disperse phase domains in simple shear flow that result in an actual coalescence. It was shown that under polymer blending conditions this “coalescence probability” is only substantial if the polymer/polymer interfaces exhibit a high degree of mobility. In the experimental part, the phenomenon of gravity induced droplet/planar interface coalescence is utilized to show the high degree of mobility of molten polymer interfaces. Seoul experiments on the relation between domain size and disperse phase concentration in polymer blends prepared on a single screw extruder were carried out. For extremely low concentration (<½ %) the domain size could be predicted satisfactorily by means of Taylor's classical criterion for Newtonian liquids, while at higher concentration coalescence increased the average domain size manifold.

Pulsation threshold patterns of synthetic vowels: Study of the second formant emergence and the center of gravity effects

Very small spectral irregularities are detected by the auditory system, thus suggesting the existence of a derivation‐like mechanism. We have already shown this fact by the estimation of formant detection thresholds in relation to the spectral pattern of a given reference [Lublinskaya et al.], J. Acoust. Soc. Am. Suppl. 1 67, S102 (1980)]. On the other hand, the center of gravity phenomenon suggests the existence of an integrationlike mechanism [Lublinskaya et al., Acts of the “Symposium Franco‐Sovietique de Grenoble,” 19–20 (1981)]. These two facts have been studied by means of pulsation threshold techniques. We have obtained psychophysical estimations of the internal representation of vowel‐like spectra, to see how these two opposite spectral mechanisms are combined, and at what level of the auditory system they are susceptible to appear. This kind of information is necessary for the elaboration of auditory perception models.

Pitch control system for large-scale wind turbines

The purpose of this analysis is to study the design of a pitching blade segment control system for the NASA-DOE MOD 0 wind turbine to alleviate some of the problems associated with shear, tower shadow, and gravity phenomena, such as shortened lifetime and noise generation. The classical linear quadratic Gaussian optimal regulator approach is used in the control formulation. A quasisteady aerodynamic analysis incorporating wind shear and tower shadow is utilized. An equivalent hinge model describes the turbine structural dynamics. The study shows that the proposed control system can provide significant vibration and noise reduction as well as a cleaner power signal, better gust response, and increased annual energy output.

Monocrystals for the investigation of gravity phenomena

The usefulness for gravity experiments of monocrystals with very high mechanical quality factors is reviewed. Measurements carried on four point mechanical suspensions at liquid helium temperature are reported. Q's of 400 × 10 6 and 47 × 10 6 have been measured for the longitudinal mode of sapphire and ruby crystals. A Q of 80 × 10 6 was measured for the bending mode of a silicon crystal.

Time, the grand illusion

The reconcilability of gravitational with electromagnetic clocks suggests that a rigorous analysis of time will provide understanding of the unity of gravity and electromagnetism. Time is found to be fundamentally a property of elementary particles, only derivatively a property of clocks. A declaration is made: that the flow of an elementary particle's timeis the change of its radius, that time is therefore illusory. The de Sitter expanding universe is derived from this principle by treating elementary particles as spheres in Euclidean space. The hyperspheres of de Sitter space call up a five-dimensional metric manifold whose geometry models gravity, electromagnetism, and other phenomena tied to the structure of matter; neutrinos are provided for. Distance in this manifold is related to a secondary time, not correlated to primary time, but just as illusory. A particle's inertial rest mass is the relative rate of its two proper times; mass and charge are jointly, not individually, conserved.

A second-order Markov Gravity Anomaly Model

A second-order Markov process is proposed as a statistical model for gravity anomalies in a local region. The method is applied to the analysis of errors in an inertial navigation system caused by unknown gravity phenomena. Statistical models of vertical deflection obtained from the anomaly model by means of the Vening Meinesz equations yield predictions of rms position and velocity errors for the navigation system. Actual vertical deflection data are used as simulated inputs to a computer model of an inertial navigator; resulting system errors are compared with errors predicted by the proposed model. The results demonstrate the validity of the second-order Markov model in analyzing errors in an inertial navigation system.

Modern Developments in Precision Clocks

ULTRA-PRECISE practical timekeepers of today can be placed within two classes, depending upon whether the restoring force is gravity, as in pendulum clocks, or elasticity, as in quartz crystal oscillators. The second class is a development of the last decade and was made possible by the vacuum tube and associated electrical circuits. Intercomparisons between timekeepers of the two classes provide a most valuable means for t he study of changes in gravity and related phenomena.