Influence Of Gravitational Forces Research Articles

Development of a device for restoration of the flowability of caked fertilizers with justification of its design and operating parameters

The article explores the possibility of use of a separate two-phase technology in agriculture to restore the flowability of caked mineral fertilizers. Flowability is one of the most important properties of fertilizers that determine their quality during storage and transportation. Flowability is understood as the property of a mineral fertilizer to flow freely under the influence of gravitational forces. Under certain environmental conditions, fertilizers may cake. To solve this problem in the preparation of fertilizers at agricultural enterprises, a new design of a preliminary grinder is proposed as a part of a two-phase technology. Based on the results of the experimental studies, the most rational design and operating parameters of the grinder have been determined. Practical recommendations on the possible use of the developed drum-type grinder for the destruction of other brittle materials in preparation for their introduction into the soil at agricultural enterprises are formulated.

Mathematical Simulation of the Exothermal Chemical Interaction in a Plug Reactor Containing Emulsion Under the Influence of Gravitational Forces

Mathematical Simulation of the Exothermal Chemical Interaction in a Plug Reactor Containing Emulsion Under the Influence of Gravitational Forces

Unveiling the Interactions between Water Molecule Clusters and Conical Structures via Molecular Dynamics Simulations.

Water scarcity presents a pressing global challenge, necessitating innovative solutions, such as the collection of water from the air using conical structures. However, current research primarily focuses on mist collection rather than on nanoscale clusters of water molecules. Under standard atmospheric conditions, water vapor predominantly exists as imperceptible clusters. Therefore, it is crucial to investigate the interactions between these water molecule clusters and conical structures, particularly regarding whether the conical shape induces Laplace pressure difference on the adhering cluster formations. To gain deeper insights and determine optimal droplet collection structures, we conducted molecular dynamics simulations to investigate interactions between water molecule clusters and conical structures. Our investigations focused on studying the interactions between conical structures and water molecule clusters with varying densities, as well as the impact of surface energies on the collection of water by these conical structures. Notably, our simulations unveiled the significant roles played by van der Waals forces and Laplace pressure in the process of collecting water molecule clusters. Furthermore, our simulations revealed that Janus conical structures, featuring two distinct surface energy regions, played a crucial role in promoting the aggregation of water molecules, resulting in the formation of larger droplets. This aggregation was driven by surface tension gradients, which arise from the contrasting wetting properties in different regions of the Janus structure. As a consequence, under the influence of gravitational forces, these larger droplets could eventually detach from the structure. Through the combined effects of surface tension gradients and gravitational forces, Janus conical structures offer a promising avenue for enhancing the collection efficiency of water from the air. Our research sheds light on the fundamental mechanisms governing water molecule cluster-based water collection and provides valuable insights for the design of more efficient and effective water collection systems.

Multiphysics simulation of fluid interface shapes in microfluidic systems driven by electrowetting on dielectrics

We present a highly efficient simulation method for the calculation of three-dimensional quasi-static interface shapes under the influence of electric fields. The method is especially useful for the simulation of microfluidic systems driven by electrowetting on dielectrics because it accounts automatically and inherently for the highly non-trivial interface shape in the vicinity of the triple-phase contact. In particular, the voltage independence of the local contact angle predicted based on analytical considerations is correctly reproduced in all our simulations. For the calculation of the shape of the interface, the geometry is triangulated and the mesh nodes are shifted until the system energy becomes minimal. The same mesh is also used to calculate the electric field using the boundary-element method. Therefore, only the surface of the geometry needs to be meshed, and no volume meshes are involved. The method can be used for the simulation of closed systems with a constant volume (e.g., droplet-based microfluidics) while preserving the volume very precisely as well as open systems (e.g., the liquid–air interface within micro-cavities or capillaries). Additional effects, such as the influence of gravitational forces, can easily be taken into account. In contrast to other efficient simulations, such as the volume-of-fluid, level-set, or phase-field methods, ideally, sharp interfaces are obtained. We calculate interface shapes for exemplary systems and compare with analytical as well as experimental results.

Development of A Novel Conceptual and Calculative Method for the Prediction of Tide within the Bay of Bengal

Ebb and flow of seawater at regular intervals under the influence of gravitational forces from outside the earth is called tides. This study sheds light on how to measure tides through a new kind of innovative method. This method can be used to measure tides at new locations based on a known tide station. Some parameters play an important role in measuring tides, such as datum information, mean sea level (MSL), mean high water springs (MHWS), mean low water springs (MLWS) and so on. This fancy method is a computational process that relies on observable data and other factors. This innovative method of measuring tides helps to get accurate information in less time and at less cost. From this study we find that the results obtained in our study are in good agreement with the results obtained by other methods and the observed data.

Influence of Three-Body Gravitational Perturbation for Drag-Free Spacecraft

This paper mainly studies the motion and control of the drag-free spacecraft system for a high-precision mission. In high-precision missions, the influence of three-body gravitational perturbation on a drag-free spacecraft system is still lack of relevant research. To this end, we first established a relative motion model of the test mass and the spacecraft based on multibody dynamics, and the equations of the relative motion of the test mass and the spacecraft cavity were obtained through coordinate transformation. The difference between the sun orbit and the Earth orbit is comparatively analyzed by a numerical solution. The influence of gravitational forces from the Earth, the moon, and the sun on the relative motion is studied in detail. Secondly, a sliding mode controller is designed for the high-precision mission. Finally, the performance of the controller is analyzed from the time domain and the frequency domain. Numerical simulation results show that the controller can meet the requirements of the time domain and the frequency domain.

ГЕОДИНАМИЧЕСКИЕ ПРОЦЕССЫ В СКЛОНЕ ПОДНЯТИЯ

The flow for the uplift slope is considered in the viscous liquid model. The relevance of the study is justified by the need for experimental and theoretical analysis of the geodynamic processes occurring in the slopes of rises. The object of the study is the slopes of rises, formed by mantle thermochemical plumes which have not come to the surface. The objectives of the study are to present the velocity profile of the viscous flow of the uplift slope and to determine the friction coefficient for it; to find out the effect of the dynamic viscosity coefficient of the slope on the appearance of compressive and tensile stresses; on the basis of laboratory and theoretical simulations to find out the hydrodynamics of the flow when the liquid flows from a rectangular vessel and using the results of geodynamic simulations to determine the flow parameters in the area of the uplift slope fault formation. The flow occurring in a viscous liquid at a constant inclination angle of the free surface of the elevation slope is considered. In a highly viscous liquid at low flow velocities, the inertial terms in the equation of motion can be neglected. For this case, the solution of the equation of motion in a layer with an inclined free surface at a constant horizontal pressure gradient is obtained. The flow velocity profile in such a layer and the relation for the maximum flow velocity are obtained. The tangential stress on the sole of the layer is determined. The tangential stress does not depend on the viscosity, but depends on the layer thickness. With a constant viscosity of the layer, the elevation slope is under conditions of compressive stresses. Strain conditions for the uplift slope are possible when the viscosity of the layer decreases with distance from the main ridge. Discontinuities occur on the elevation slopes due to changes in viscosity along the slope and changes in the velocity. Under the influence of gravitational forces caused by the density difference at the rupture boundary, flow occurs and the resulting free volume is filled. The motion in a highly viscous liquid during the formation of a free vertical surface has been studied experimentally when liquid flows out of a transparent rectangular vessel. Photographs of the free surface were obtained. A linear dependence of the relative height of the free surface location on the relative horizontal coordinate is observed. Expressions are obtained for the average velocity and expiration time of a viscous liquid from a rectangular vessel. Estimates of the average velocity and outflow time for the specified slope parameters are presented

IDENTIFYING THE MAIN FEATURES OF LANDSLIDE MOVEMENT AND DEVELOPING THE BASIC MECHANISMS

The results of studies of the mechanisms and main features of the movement of fast and extended clayey and other landslides are presented. Landslides are said to cause about 1,000 deaths and $4 billion losses of property each year. However, at least 90% of all landslide losses could have been avoided if the problem had been recognized in advance. At present, as a result of a preliminary statistical analysis, results have been obtained that generally explain the occurrence of the onset of landslides. On their basis, three mechanisms were explained that cause the movement of the geomass of landslides: under the influence of gravitational forces, fluidization and lubrication of the landslide bed along the base of the main guides. However, additional research has found that those gravitational forces do not ensure the movement of significant geomasses over long distances. The third mechanism we have identified is the participation of nanoparticles of the lower layer of the moving landslide as natural nano-bearings. Halloysite nanoparticles have been studied, which are nanotubes (having a length of 0,5...2 μm and an outer diameter of about 200 nm, with a lumen diameter of 10...15 nm), in which sheets of aluminosilicate are coiled into a spiral. Typically, the shells of such hallusite pipes include 15...20 layers. In addition, halloysites, depending on the conditions of crystallization and geological structure, may have another morphology (such as, for example, spheroidal or disk), which also plays the role of nano-bearings that contribute to the movement of the landslide geomass.

الكتلة السالبة

يقدم هذا البحث نموذجًا فيزيائيًا يصف أفكار النسبية الخاصة من خلال طريقة أكثر عقلانية ومنطقية وبسيطة ومفهومة، مع استخدام الأدوات الرياضية الأساسية. إذ يعتمد النموذج على صيغة ألبرت أينشتاين، التي تصف طاقة "الراحة" لجسم ذي كتلة m من خلال الصيغة E = mc2. بناءً على الصيغة المرفقة، ووفقًا لنظرية النسبية الخاصة، نقدم خلال هذا البحث نموذجًا لجسم يتحرك بسرعة عالية وثابتة في الفضاء مع سرعة تساوي سرعة الضوء في الزمكان "Space Time"، تحددها "زاوية الحركة" "والكتلة السالبة". في الجزء الأول، يقدم هذا النموذج طريقة لإنشاء كتلة سالبة، وطريقة لحساب السرعة النسبية، والطاقة والزخم، في تصادم المرن مثالي وآخر غير مرن، يختلف عن الطرق المعاصرة في الوقت الحالي، باستخدامه للفيزياء الكلاسيكية والحديثة. إضافة لكون النموذج الجديد يحل المشاكل والمفارقات المعروفة في فيزياء النسبية الخاصة بشكل أفضل، مثل مفارقة التوأمين The Twin Paradox وغيرها. في الجزء الثاني، يناقش البحث تطبيق النموذج على الجسم تحت تأثير قوى الجاذبية وفي الجزء الثالث الأخير يتضح كيف يمكن تفسير الظواهر في فيزياء الكم وفقًا لنفس النموذج.

The use of the interaction of convex wall jets for ventilation with variable air flow

The most energy efficient ventilation and air-conditioning is variable air flow (VAV) depending on the needs of a room. To avoid broken air circulation by gravitational forces, the most of air diffusers should change geometrical shape and sizes using additionall automation of them. In contrast, high stability of a scheme of air exchange organization with air supply over a working zone by convex wall jets that interact with each other under conditions of variable air flow, is confirmed. This scheme is useful in cases where it is impossible to supply air directly to the working zone. Simulation of the air exchange organization in an exhibition hall of International Exhibition Centre in Kyiv with ventilation at a variable air volume (VAV) in the entire possible range of performance control has been performed. The floor area is 5258 m2, the height is 19 m. The outdoor air-flow at design conditions (100 % load) is 21.667 m3/s (78000 m3/h). The minimum load corresponds to the absence of solar radiation and only some people in the room. The minimum air-flow is 25 % of the design one. The proposal air scheme is single-zonal using 24 diffusers PES-D-8-10/15-0,9 4 m above the floor and air removal from the upper zone. The air distributor have a diameter of a cylindrical surface and an inlet branch pipe of 8 dm (800 mm). There are 10 rows of nozzles at an angle π/12 (15 °) to the horizon on each distributor. The total area of the air outlet on them is equal to 0.9 of the cross-sectional area of the inlet pipes. Due to forces of the vacuum holding of jets on the wall surfaces, the influence of gravitational forces is significantly reduced. This avoids the automation of air distribution devices to stabilize the scheme of air circulation in the room by gravitational forces. It is enough to install valves with actuators on branches of a network of air ducts. Thus, the economic benefit of the system is confirmed both at the stage of installing and during operation.

Modern warming, medieval and ancient optimums as the result of orbital changes in the Earth-Moon-Sun system

The root cause of modern climate warming is the influence of gravitational forces on the geospheres of our planet, determined by the orbital configuration of the Earth-Moon-Sun system. The annual changes in the position of the total vector of gravitational forces in space visually reflects the movement of the shadow cone of solar eclipses around the globe. The aim and novelty of the study is to identify the relationship between the number of years with four to five polar eclipses (in periods of pessimums, their number reaches 15-17 years, and in periods of optimums – 2-7 years in a century) and glaciation processes, such as the Fernau fluctuation, Late Antique Little Ice Age, or processes of warming and degradation of glaciers in the Roman and Medieval optimums. The research methods were study, generalization of materials, data synthesis, logical and graphical analysis. The anthropogenic causes of modern warming, which will last until the middle of the 22nd century, are secondary. In the second half of the 22nd century, and throughout the entire 24th century, the advance of the alpine glaciers will be associated with the conditions of the climatic pessimum. Solar activity, planetary factors and processes - volcanic activity, current intensity, heat transfer with the World Ocean – can noticeably strengthen or weaken both the manifestation of optimums and pessimums. The results of the study, taking into account other factors, can be used in the retroanalysis of the periods of glaciation in centuries before the Common Era and the prediction of them in the future.

Investigation of the influence of gravitational forces on the process of displacement of viscoplastic fluids

The object of research is a numerical simulation of the process of two-dimensional two-phase filtration of viscoplastic oil and water, taking into account the gravitational forces, some properties of liquids, as well as relative phase permeabilities and capillary forces.As is known, the problems of multiphase filtration have specific features. Therefore, there is a need to develop difference schemes in adaptive grids that reduce the artificial viscosity and oscillation of the numerical solution. They also make it possible to obtain acceptable results with a small number of nodes in the computational grid.To take into account the singularities of the solution, a difference-iteration method is used in moving grids. Based on the computational experiment, the influence of the initial pressure gradient and gravity on the displacement process is investigated.Economical difference schemes that combine the advantages of explicit and implicit schemes are constructed and make it possible to reduce the two-dimensional problem to a chain of one-dimensional problems. A difference-iterative method is also proposed in moving grids for solving two-dimensional (axisymmetric) non-stationary filtration problems of anomalous liquids, by means of which an iterative process is constructed to find the distribution of water saturation.The carried out calculations to determine the influence of gravity on the displacement process have shown that at z=0, even at low productive-bed thicknesses, gravitational forces influence the displacement process. And over time this influence increases: if at the time t=0.08 on the circuit the difference of water saturation was 0.0077; at t=0.24–0.0122, then at t=1.04 it becomes equal to 0.0292.It is shown that when modeling the process without taking gravity into account it is expedient to simplify the geometry of the filtration region, i. e., to consider a plane-radial flow in view of the considerable simplicity of the calculations.The developed algorithms can be used for hydro-gas dynamic calculations related to the development and operation of oil fields containing anomalous oil.

Critical heat flux density in diphasic thermosyphons

The paper presents an analysis of known dependencies for determining the critical heat flux density in diphasic thermosyphons. The critical heat flux density for the created experimental model of thermosyphon were calculated on the basis of the theoretical contributions of 1) the occurrence of a “flooding” regime in a thermosyphon characterized by a disturbance of the hydrodynamic stability of the phase interface and the entrainment of the liquid phase by the gas flow; 2) the mutual influence of gravitational forces and surface tension; 3) S.S. Kutateladze hydrodynamic theory of the heat transfer crisis during boiling. It is found that the existing theoretical contributions which can be used to calculate the critical heat flux density and subsequently determine the minimum filling ratio of a thermosyphon are conditionally applicable.

Experimental estimation of characteristic times of the existence of liquid drops in the form of a sphere and ellipse upon their movement in a gas environment under the conditions of moderate weber numbers

The experimental procedure has been developed and studies using high-speed (105 frames per second) system of cross-correlation video registration of a change in the shape of drops for the most typical liquids that are widely used in various chemical technologies (water, kerosene, and ethyl alcohol) have been carried out. The liquids move with significantly subsonic speeds (up to 5 m/s) in the air environment under the influence of gravitational forces. The initial sizes of drops varied in the range of 3–6 mm. The cyclic nature of the changes in the shapes of drops during movement has been established. Characteristic times of transitions from one shape of drop to another have been measured. Characteristic times of the existence of drops in the form of spheres and ellipses have been defined. Recommendations about the use of geometrical models of liquid drops for theoretical study of heat and mass transfer and hydrodynamics in the course of their movement through gas environments under the conditions of moderate Weber numbers have been formulated.

On the motion of rigid bodies in an incompressible or compressible viscous fluid under the action of gravitational forces

The global existence of weak solutions is proved for the problem of the motion of several rigid bodies eitherin a non-Newtonian fluid of power law type or in a barotropic compressible fluid, under the influence of gravitational forces.

The Yarkovsky effect in generalized photogravitational 3-body problem

Here a generalization of photogravitational restricted 3-body problem to the case of influence of Yarkovsky effect is presented, which is known as the reason of additional infinitesimal acceleration of small bodies in the space (due to anisotropic re-emission of absorbed energy from the sun, and other stellar sources).Asteroid is supposed to move under the influence of gravitational forces from 2 massive bodies (which are rotating around their common center of masses on Kepler's trajectories), as well as under the influence of pressure of light from both the primaries.Analyzing the ODE system of motion, we explore the existence of equilibrium points for a small body (asteroid) in the case when the 2-nd primary is non-oblate spheroid.In such a case, the existence of maximally 256 different non-planar libration points in generalized photogravitational restricted 3-body problem when we take into consideration even a small Yarkovsky effect is proved.

Epigenetic inheritance systems act as a bridge between ecological and evolutionary timescales

A long-standing problem in biology is reconciling phenotypic change and stability. Organisms are extraordinarily plastic, responding to life-stage transitions, seasonal cues, and environmental change. Some of these changes are permanent and some are reversible occurring thousands of times during a lifetime. Yet, at the same time, phenotypic stability is equally evident, enabling reliable assignment of individuals into morphs, populations, and species. A key question in evolution is how these timescales of phenotypic change are linked. The traditional view is that they are not such that there is a dichotomy of “ephemeral environmental effects” and “stable genetic effects” with only the latter relevant to evolutionary change. However, as Ledon-Rettig et al.’s review shows, this view needs to be updated as we learn more about the proximate mechanisms behind genetic and epigenetic determinants of phenotypic variation. Purely environmental influences on the phenotype are often assumed to be more transient than genetic effects and thus not important for long-term evolutionary change. However, environmental influences on the phenotype are often more stable then genetic influences—the most extreme example being the influence of gravitational forces—a factor that has consistently influenced the form and function of all organisms. However, genetic influences on the phenotype are often assumed to be the most stable. Yet, genetic variants that map onto phenotypic variation consistently irrespective of the environmental and genetic context are extremely rare. Instead, the phenotypic effects of specific DNA sequences is often highly variable from one generation to the next depending on both genetic background and environmental context. Similarly, as Ledon-Rettig et al. show, the stability of epigenetic effects are also not easily categorized and can range from transitory cell state modifications that can change over the course of development to multigenerational influences of a mother’s behavior on her descendants. These observations show that there is not a simple dichotomy in the timescales of phenotypic expression and that a more realistic view is of a gradation of stability that does not map onto genes versus environment in a simple way.

Supernova Remnants in Starburst Regions

AbstractWe study the evolution of SNRs in starburst regions taking into consideration the role of the high ambient pressure and the influence of gravitational forces from the stellar component within the shell of a SNR. On this basis, we discuss the connection between the radio, infrared, and gamma emissions from starburst regions.

Modeling Flow Transitions during Buoyancy‐Driven Gas Migration in Liquid‐Saturated Porous Media

We conducted a pore network modeling study of the influence of different fluid and rock properties on gas migration under the influence of gravitational forces. Transitions from continuous, capillary‐dominated flow, through gravitationally biased fingering and discontinuous braided migration, to discontinuous dispersive (bubbly) flow were investigated using both small‐scale (1‐cm) and macro‐scale (100‐cm) networks. Our simulation results were found to closely match a wide range of published experimental observations and the model is the first to comprehensively explain the influence of several pore‐scale properties on buoyancy‐driven migratory patterns. We found a transition from continuous, compact, capillary‐dominated flow to discontinuous “dispersive” flow as the relative strength of buoyancy forces increased. We found that the governing regime is strongly affected by the mean capillary radius, pore‐size distribution variance, gas–liquid interfacial tension, and the underlying connectivity of the porous medium. We also investigated the implications of these system properties and associated boundary conditions for air sparging efficacy.

Publisher's Note: Influence of gravitational forces and fluid flows on the shape of surfaces of a viscous fluid of capillary size [Phys. Rev. E79, 025302 (2009)

Publisher's Note: Influence of gravitational forces and fluid flows on the shape of surfaces of a viscous fluid of capillary size [Phys. Rev. E79, 025302 (2009)