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This paper considers the approach proposed by Zou et al. for determining the plastic zone around a shallow circular tunnel in an elasto-plastic semi-infinite space that incorporates the gravitational effect based on the bipolar coordinate system. The paper aims to analyze the correctness of the analytic expressions for elastic and plastic stress, as well as the reasonableness of the procedure building for solving the elasto-plastic interface. Finally, a promising way of solving this problem more exactly is presented.

Although profiles of axisymmetric capillary bridges between two cylindrical fibers have been extensively studied, little research has been reported on capillary bridges under external forces such as the gravitational force. This is because external forces add significant complications to the Laplace–Young equation, making it difficult to predict drop profiles based on analytical approaches. In this paper, simulations of capillary bridges between two vertically stacked cylindrical fibers with gravitational effect taken into consideration are studied. The asymmetrical structure of capillary bridges that are hard to predict based on analytical approaches was studied via a numerical approach based on Surface Evolver (SE). The axial and the circumferential spreading of liquids on two identical fibers in the presence of gravitational effects are predicted to determine when the gravitational effects are significant or can be neglected. The effect of liquid volume, equilibrium contact angle, the distance between two fibers and fiber radii. The simulation results were verified by comparing them with experimental measurements. Based on SE simulations, curves representing the spreading of capillary bridges along the two cylindrical fibers were obtained. The gravitational effect was scaled based on the difference of the spreading on upper and lower fibers.

In this work, a visual two-dimensional (2D) heterogeneous fracture network model was designed to investigate CO2 foam generation, propagation and sweep with two different injection strategies (co-injection, COI; and surfactant solution alternating gas, SAG). In addition, gravitational effect was explored by this fracture model. In the case of the optimum foam quality (fg = 0.67), the results indicated the COI could form stable foam morphologies and differential pressures (ΔP), while the foam morphologies and ΔP showed a dynamic trend during each cycle of SAG. The ΔP of larger slug injection can establish 6–12 times than smaller slug injection in the fractured system. Because of CO2 breakthrough, the total sweep efficiency of continuous gas injection (CGI, 42%) and SAG (66%) were lower than COI (81%). Gravitational effect is insignificant during COI, whereas gravity has a considerable effect on SAG in terms of ΔP and sweep efficiency. As a result of gravitational effect, the entire ΔP curve decreased and required more fracture volume (FV) injected to achieve the final sweep efficiency during SAG. The results of this study provide preliminary observations that can provide new insights into mobility control by using CO2 foam in fractured tight reservoirs.

Facing the serious issues of using chemical agents in agro-industry and polluting the soil and water source, the solid microbial fuel cell (SMFC) would be one of solution on managing this problem because of undergoing the compost fermentative process to degrade solid waste effectively and also produce power. Now facing the fact of that water content directly impacts the degrading performance of microorganism during the composting process, a technique of Xanthan 80 Smoother flow(SF) and a drainage design would be utilized in the system undergoing a series of studies for knowing its performance of SMFC. Results show that using Xanthan 80(SF) can enhance the power performance of SMFC significantly because of its excellent ability on keeping the compost moist throughout and preventing the gravitational effect from the accumulation of water at the bottom of the chamber. These findings will be useful to modification of SMFC in the future.

Liquid-nitrogen (LN 2 ) circulation systems with altitude variation are investigated and designed for application to practical long-length HTS cables. This study is motivated by the KEPCO’s immediate plan to install new HTS cables in existing utility tunnels including inclined and vertical sections. The distribution of pressure and temperature along the LN 2 circulation loop is examined for various geographic conditions, taking into account the gravitational effect of altitude variation. The cryogenic cooling requirements are defined in terms of the pressure and temperature of LN 2 , and a design process is graphically demonstrated on phase diagram. It is concluded that the LN 2 flow rate along the cable with altitude variation should be carefully determined with the constraints on pressure and temperature, and the proposed graphical method is useful in the design.

In this paper, we investigated physical characteristics of an artificial supercavity generated behind an axisymmetric cavitator. Experiments for the same model were carried out at two different cavitation tunnels of the Chungnam National University and the University of Minnesota, and the results were compared and verified with each other. We measured pressures inside the cavity and observed the cavity formation by using a high-speed camera. Cavitation, parameters were evaluated in considering blockage effects of the tunnel, and gravitational effects on supercavity dimensions were examined. Cavity dimensions corresponding to the unbounded cavitation number were compared. In addition, we investigated how artificial supercavitation develops according to the combination of injection positions and direction. Copyright (C) 2016 Society of Naval Architects of Korea. Production and hosting by Elsevier B.V.

At present, the theoretical understanding of the collisional interaction between particles and a single bubble under well-defined laminar flow conditions is relatively sound. However, there is a lack of experimental data and predictions on details of the interaction processes in stirred turbulent conditions, as exists in mineral flotation cells. This paper investigates the effect of turbulence on the efficiency of collision between particles and bubbles from a fundamental point of view. A computational fluid dynamics method is used to establish a bubble–particle collision efficiency model system for turbulent flow. The 3D model is used to systematically study the effect of fluid turbulence on bubble–particle collision efficiency. In order to isolate the phenomena caused by turbulent flow physics, the study is conducted in two parts: large-scale turbulence and small-scale turbulence, which are respectively larger and smaller than the bubble size. Large-scale turbulence is assumed to increase the speed of bubbles relative to the slurry, and in most cases, increase in the speed increases collision efficiency, though in some cases the gravitational effect can cause decrease in overall efficiency. Small-scale turbulence is treated through the effect of fluctuations on particle trajectories. Again, such turbulence increases collision efficiency when the turbulent particle Stokes number is less than or about unity, but has little effect for Stokes number much greater than unity. An equation for the increase in efficiency in the limit of small Stokes number is obtained from the simulations.

Experiments carried out using a lung model with a single horizontal bifurcation under different steady inhalation conditions explored the orientation of depositing carbon fibers, and particle deposition fractions. The orientations of deposited fibers were obtained from micrographs. Specifically, the effects of the sedimentation parameter ( γ ), fiber length, and flow rate on orientations were analyzed. Our results indicate that gravitational effect on deposition cannot be neglected for 0.0228 γ γ for values 0.0228 γ γ suggests these characteristics can be used to estimate fiber deposition in the lower airways. Computer simulations with sphere-equivalent diameter models for the fibers explored deposition efficiency vs. Stokes number. Using the volume-equivalent diameter model, our experimental data for the horizontal bifurcation were replicated. Results for particle deposition using a lung model with a vertical bifurcation indicate that body position also affects deposition.

This paper focuses on the role of L3 to organise trajectories for a particle going from Earth to Moon and viceversa, and entering or leaving the Earth-Moon system. As a first model, we have considered the planar Bicircular problem to account for the gravitational effect of the Sun on the particle. The first step has been to compute a family of hyperbolic quasi-periodic orbits near L3. Then, the computation of their stable and unstable manifolds provides connections between Earth and Moon, and also generates trajectories that enter and leave the Earth-Moon system. Finally, by means of numerical simulations based on the JPL ephemeris we show that these connections can guide the journey of lunar ejecta towards the Earth.

This paper studies whether rule-based circuit breakers in the form of short-lived volatility interruptions exhibit a magnet effect in times of high-frequency trading. Based on a sample of 3,271 volatility interruptions on two major European venues, we analyze whether trading aggressiveness, trading activity, and volatility accelerate close to volatility interruptions indicating a magnet effect. Although the duration of the interruptions is meaningful given today's high-frequent securities markets, we do not find any evidence for a magnet effect. Rather, our results show that trading aggressiveness, trading activity, and volatility gradually slow down towards the triggering threshold and that price changes even revert in case of downward-triggered interruptions. These findings hold both for different levels of high-frequency trading activity and for disclosed and undisclosed price limits triggering the circuit breaker.

By taking gravity and joint/link compliances into account, this paper presents a semi-analytical approach for compliance analysis of a 3-SPR parallel mechanism which forms the main body of a 5-DOF hybrid manipulator especially designed for high-speed machining and forced assembling in the aircraft industry. The approach is implemented in three steps: (1) kinetostatic analysis that considers both the externally applied wrench imposed upon the platform and the gravity of all moving components; (2) deflection analysis that takes both joint and link compliances into account; and (3) formulation of the component compliance matrices using a semi-analytical approach. The advantage of this approach is that the deflections of the platform caused by both the payload and gravity within the given task workspace can be evaluated in an effective manner. The computational results show that the deflection arising from gravity of the moving components may have significant influence on the pose accuracy of the end-effector.

In this Letter we study the effects of the Modified Uncertainty Principle as proposed in [8] on the inflationary dynamics of the early universe in both standard and Randall-Sundrum type II scenarios. We find that the quantum gravitational effect increase the amplitude of density fluctuation, which is oscillatory in nature, with an increase in the tensor-to-scalar ratio., new references added

The dynamics of a flexible beam forced by a prescribed rotation around an axis perpendicular to its plane is addressed. Three approaches are considered, two of them related with simplified theories, within Strength of Materials, and the third one using Finite Elasticity. In the Strength of Materials approaches, the governing equations of motion are derived by superposing the deformations and the rigid motion in the first model, and in the second by stating the stationarity of the Lagrangian (including first- and second-order effects in order to capture the stiffening due to the centrifugal forces) through Hamiltons principle. Two actions are considered: gravity forces (pendulum) and prescribed rotation. Comparison of the two Strength of Materials models with the model derived from Finite Elasticity is carried out. Predictions for the same problems, interpreted in the context of the specific model, are compared and it was found that sometimes they give rather different results, both in the results and in the computational cost. Energy analyses are performed in order to obtain information about the quality of the numerical solutions. The paper ends with an example of a pendulum with a finite pivot including friction and flexibility. When the structural elements are sufficiently slender and the rotational speeds are low, so that the resulting deformations are small, the Strength of Material model that includes the load stiffening and the Finite Elasticity approach, lead to similar results. It can be concluded that the stiffening phenomenon is appropriately considered in the first model. On the contrary, when the Strength of Material hypothesis are not fulfilled, the problem should be addressed via the Finite Elasticity model. Additionally, cases with complexities such as friction at a finite pivot can only be addressed by Finite Elasticity. Fil: Buezas, Fernando Salvador. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Física; Argentina Fil: Sampaio, Rubens. Pontifícia Universidade Católica do Rio de Janeiro; Brasil Fil: Rosales, Marta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería; Argentina Fil: Filipich, Carlos Pedro. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería; Argentina

Liquid bridge force acting between wet particles is an important property in particle characterization. This paper deals with liquid bridge force between either two unequal-sized spherical particles or a sphere and a flat plate under conditions where gravitational effect arising from bridge distortion is negligible. In order to calculate the force of the liquid bridge efficiently and accurately, expressions of liquid configuration and liquid bridge force were derived by building a mechanical model, which assumes the liquid bridge to be circular in shape between either two unequal-sized spheres or a sphere and a plane. To assess the accuracy of the numerical results of the calculated liquid bridge forces, they were compared to the published experimental data.

When bicontinuous gels are prepared via sol-gel method in a 2-dimensionally (2D) confined space, the gel skeletons in the vicinity of interface of a mold are elongated perpendicular to the interface. This phenomenon was attributed to the dynamic wetting of polymerizing siloxane phase onto the interface of the mold under gravity. In this paper, we report the successful preparation of monolithic columns with an oriented pillar structure in a variety of 2D confined spaces. Starting from a solution, which consists of methyltrimethoxysilane (MTMS), the macroporous structure is prepared in situ by a completely spontaneous process. In the oriented pillar structure, bicontinuous siloxane skeletons deformed or disappeared and most pillars are oriented along the direction of gravity. Gel morphologies with the pillar structure were examined by scanning electron microscopy (SEM) and laser scanning confocal microscopy (LSCM). Geometrical information on gel morphologies was numerically derived from the obtained 3D LSCM images.

Annular flow is an important flow regime in many industrial applications. The need for a better understanding of this flow regime is driven by the desire to improve the design of many terrestrial and space-based systems. Gravity is a complicating factor in the studies and modeling of two-phase flows on earth. Experimental data on the annular flow film characteristics was collected in microgravity aboard the Novespace Zero-G Airbus microgravity simulator. The gravitational effect on the film thickness characteristics was examined by collecting data using an air-water mixture during the microgravity and pull-up (hypergravity) portions of each parabolic flight. Previously reported trends in annular flow average film thickness values for normal gravity are observed in microgravity and hypergravity conditions. The change in gravitational acceleration has little effect on the average film thickness and the film thickness time trace. However, the wave characteristics vary significantly.

The relaxation time height dependence τ(z) for inhomogeneous mixtures under gravity close to the consolute critical point is studied in this paper by means of using refractometric technique and is shown to have a non-monotone character. The maximum value of the relaxation time corresponds to the height z0, where isotherms dn/dz(z,t) intersect in a system going to equilibrium. It is shown on the basis of the fluctuation theory of phase transition and gravitational effect theory that properties of the inhomogeneous substance at the extremal points of τ(z) simultaneously contain properties of homogeneous systems along three critical directions, namely critical isochor, critical isotherm and phase interface. Relaxation properties of dn/dz are described not by a single relaxation time τ(z), but rather by a set of the relaxation times Στi(zj), which characterises the inhomogeneous system as a whole under gravity close to the consolute critical point.

The observed absence of gravitational aberration requires that ``Newtonian'' gravity propagate at a speed $c_g>2\times10^{10}c$. By evaluating the gravitational effect of an accelerating mass, I show that aberration in general relativity is almost exactly canceled by velocity-dependent interactions, permitting $c_g=c$. This cancellation is dictated by conservation laws and the quadrupole nature of gravitational radiation., 9 pages, LaTeX, one figure using LaTeX picture environment; references added, abstract shortened, typos corrected, discussion of aberration and radiation reaction amplified; no change in essential argument

We have studied theoretically the effect of gravity on the rough solid-liquid interface and have shown that its tension is enhanced by gravity when gas is adsorbed at it. As a result, the apparent contact angle on rough surfaces, which has been considered not to be influenced by gravity so far, can be raised by gravity. The calculated dependence of contact angles on gravity under the ordinary conditions of the sessile drop method is large enough to detect by experiment. The observed asymmetrical deviations from Wenzel's contact angle caused by the gas adsorption at the solid-liquid interface and by the liquid adsorption at the solid-gas interface are explained in terms of this gravitational effect. Copyright 1999 Academic Press.

We have examined a modified dilaton gravity whose action is separable into the kinetic and the cosmological terms for the sake of the quantization. The black hole solutions survive even in the quantized theory, but the ADM mass of the static solution is unbounded from below. Quantum gravitational effect on the interacting matter field and the string susceptibility of the dilaton gravity are also examined., Comment: 12 pages, LaTex

A point of source of light against a dark background is perceived by the human retina as a point image enhanced by off-axis points (rays if the source is polychromatic) of light scattered from objects along the optic axis. As a consequence of movement of the vitreous humor, scattering centers imbedded there impart of this scattering pattern a corresponding movement. A method has been devised to give the vitreous humor reproducible initial conditions and to record the observed relaxation of the scattering pattern to its new rest position. The vitreous humor is found to be overdamped, and the heretofore unreported shear elastic modulus has been determined. A striking gravitational effect is revealed by comparing observations along a horizontal optic axis with ones along a vertical optic axis. For the former, gravitational torque is found to dominate the elastic torque. The reason nature has developed a slow-responding gravitational sensor in the vitreous humor is not clear.

In the very early universe with temperature T between 1024 K and 1032 K the gravitational effect of torsion is dominant if particles with spin are sufficiently polarized. The source of the torsion is the spin density and the latter is usually described by a classical theory of Weyssenhoff and Raabe. In this article the spinning particles are described quantum mechanically, i.e. with a Dirac field and the spin density is defined as the source of the torsion. The macroscopic average of the spin density is obtained by the relativistic Wigner function formalism. The expression of the spin density, as derived in this article, is different from the classical one, except when both are zero.

A modified transform function ω 2 A(ω) sin ωb where A ( ω )is the amplitude spectrum of a dike's gravitational effect is defined. It is shown that the slope of the linear portion of the plot of ln F 2 ( ω ) against ω is equal to the depth to the top of the dike and the intercept of this portion on the ω-axis is 4 πG ρ sin i where ρ is the density and i the inclination of the dike. The dip and density can be separately estimated from a similar treatment of the phase spectrum.

It is shown, by applying the positive-energy theorem, that the present vacuum (M 4 ×K D ) in some higher-dimensional theories (e.g. the Candelas-Weinberg model) is stable against decay by quantum tunnelling without change of topology. Frieman and Kolb have found a quantum tunnelling instability of the present vacuum in the same models. But they did not take into account the gravitational effect, which is important and prevents the universe from decaying into the higher-dimensional de Sitter phase.

Relative motion of the various parts of the rib cage of rabbits and dogs during passive and active inflation was related to corresponding pressure across the rib cage (Prc) under the following conditions: (a) supine and head-up postures, (b) normal and eviscerated, (c) with and without pneumothorax. Local specific distensibility of the rib cage was nearly uniform in relaxed supine animals, whereas in the head-up posture it was larger in the caudal parts, particularly in the normal animals. Local distensibility was similar in animals with or without pneumothorax, being essentially related to the gravitational effect on the abdomen and the rib cage. In spontaneously breathing supine animals local distensibility was still uniform and larger than in relaxed animals; in the head-up posture that of the caudal parts was smaller than that of relaxed animals whereas that of the cranial parts was larger. The features of rib cage motion were in line with the different behaviour of the vertical gradient of transpulmonary pressure during active and passive expansion of the respiratory system.

Lunar solar perturbation effect on orbital lifetimes of artificial satellites with highly eccentric orbits

Calculations on convection in Newtonian fluids at large Rayleigh numbers show behaviour in general agreement with geophysical observations. The calculated values of surface velocities, regional gravity and topographic anomalies all lie within the range of values found at the earth's surface. The sign of the gravity anomaly over rising fluid is positive because the gravitational effect of the surface deformation is greater than that of the density deficit. This result appears to agree with geophysical observations and should permit the flow within the mantle to be followed in some detail.

Silicone molds can be fitted precisely to skin grafted, depressed surgical defects of the leg and can be secured in place with a tight-fitting elastic support. The gravitational effect and resultant edema under the skin graft can be reduced. Earlier ambulation and better results than have been reported in the past can be obtained.