A Clustering Approach Based on Charged Particles

This paper presents a charged system search optimization method for finding the optimal cluster centers in a given dataset. CSS algorithm utilizes the Coulomb and Gauss laws from electrostatics to initiate the local search, and Newton second law of motion from mechanics is employed for global search. The efficiency and capability of the proposed algorithm are evaluated on seven datasets and compared with existing $$K$$ -means, GA, PSO and ACO algorithms. From the experimental results, it is found that the proposed algorithm provides more accurate and effective results than other methods being compared.

Nonlinear drag force has been a research frontier in complex gas-solid systems. The literature has reported that the commonly-used drag correlations often overestimate drag force and, thus, cause unrealistic homogeneous flow structures in gas-solid fluidized beds of fine particles. For solving this problem, the structure-dependent drag model, derived from energy-minimization multi-scale approach, is used in discrete simulations of fluid catalytic cracking particles in a small riser. The gas phase is dealt with by computational fluid dynamics. Particles are considered as a discrete phase and described by Newton’s second law of motion. Gas-particle phases are coupled according to Newton’s third law of motion. Simulations show that use of structure-dependent drag model results in drag reduction, the effect of which is not so apparent as that in simulations of the two fluid model. The particle clustering tendency, however, is more distinct and leads to more heterogeneous flow structures in riser flow with a much greater amplitude of outlet solid flux fluctuations. Moreover, the behaviors of particle and gas back-mixing can be captured in the present simulations, which was supported by past simulations and experimental data. The simulation time resolution is discussed. The spring constant can be artificially brought down for safe setting of larger time step when modelling the collision process between fine particles with a higher calculation load. To appropriately mimic the continuous decay of van der Waals force may, however, need a much smaller time step. There is also an obvious effect of space resolution on simulations. When using a grid size smaller than 3 times the particle diameter, the simulated clusters turn extraordinarily large, and the effect of gas-solid back-mixing turns insignificant.

A further investigation to mechanism of the electrorheological effect of waxy oils: Behaviors of charged particles under electric field

Dark matter could meet its nemesis on Earth

Introduction. One of the high points of elementary calculus is the derivation of Kepler's empirically deduced laws of planetary motion from Newton's Law of Gravity and his second law of motion. However, the standard treatment of the subject in calculus books is flawed for at least three reasons that I think are important. First, Newton's Laws are used to derive a differential equation for the displacement vector from the Sun to a planet; say the Earth. Then it is shown that the displacement vector lies in a plane, and if the base point is translated to the origin, the endpoint traces out an ellipse. This is said to confirm Kepler's first law, that the planets orbit the sun in an elliptical path, with the sun at one focus. However, the alert student may notice that the identical argument for the displacement vector in the opposite direction would show that the Sun orbits the Earth in an ellipse, which, it turns out, is very close to a circle with the Earth at the center. That would seem to provide aid and comfort to the Church's rejection of Galileo's claim that his heliocentric view had more validity than their geocentric one. Second, by placing the sun at the origin, the impression is given that either the sun is fixed, or else, that one may choose coordinates attached to a moving body, inertial or not. However, Newton's equations in their usual form hold precisely in inertial coordinates. Furthermore, it is an immediate consequence of Newton's Laws that the center of gravity of the two bodies can serve as the origin of an inertial coordinate system. One then finds that both the Earth and the Sun describe elliptical paths with a focus at the center of gravity of the pair. Third, by considering only the displacement vector, the treatment misses an opportunity to present one of the greatest recent triumphs of Newton's derivation of Kepler's Laws: the discovery of extrasolar planets during the past decade, none of which has been observed directly, but whose existence and orbital parameters have been deduced by detecting and analyzing the motion of the stars that they orbit. Two other considerations make the correct way of treating the subject particularly desirable. First, the current treatment for the displacement vector could be left as is, and only a little algebra is needed to show that the same vector referred to the center of gravity is a constant scalar multiple of the one referred to the sun. Second, it connects with an exciting area of current research in astronomy where the methods of elementary calculus have direct application. The purpose of this note is to spell out the slight modifications to the standard treatment of Kepler's Laws that are needed to obtain the additional and accurate information, and to provide a user's guide to the website http://exoplanets.org where a list of all the extrasolar planets discovered so far is maintained and constantly updated. The Basic Equations. Let r(t) be a (3-dimensional) vector function of the parameter t, and suppose that r(t) satisfies the differential equation

Space and time, inertia and gravity are unseen yet they are the most fundamental concepts needed to understand physics classically, relativistically, and quantumly. Non- Euclidean geometries and relativity theory have yielded new insights in treating the four interrelated metaphysical concepts. Minkowski linked time and space. Einstein linked Newton’s first and second laws of motion. Attempts to link electromagnetism / gauge forces to theories of gravity have been somewhat of a challenge. Could discrete inertia be the unrecognized link between quantum mechanics and relativity theory? Newtonian mechanics and Maxwell’s equations are based on the mathematics of continuous functions and relativistic effects count Newtonian laws as approximations. The classical period of physics, based on ideas of continuity came to an end when discreteness and quantum considerations, like the Planck black-body spectrum, became experimentally and theoretically relevant. General relativity and quantum mechanics have reshaped our way of thinking about classical geometric concepts of space and time as well as inertia and gravity. Unsolvable mathematical frameworks have not provided the inertial / gravitational and space / time superstructures needed to address the unification problem. The first attempts to link gravity to the behavior of subatomic particles originated in papers written by two Russian physicists. Sakharov proposed that Newtonian gravity could be interpreted as a dipolar van der Waals force that emerges from the action of quantum fluctuations of the empty vacuum. Zeldovich gave a new meaning to Einstein’s cosmological constant, as a measure of the curvature of space, allowing for new insights into cosmological inflation and dark energy. It will be argued in this paper that zero-point fluctuations which produce inertial reaction forces also produce the elasticity / curvature of spacetime suggested by Sakharov / Zeldovich. Is it possible that dynamic spacetime gives matter its curvature? We will attempt to show the feasibility of this idea by appealing to Rowlands quaternion representation of spacetime and gauge / gravity duality hypothesis. We will then argue that Sakharov’s induced continuous gravitational field emerges which balances the discrete inertial spacetime forces satisfying a zero-totality condition.

The behavior of charged particles in low‐frequency geomagnetic pulsations is examined with particular emphasis on what a spacecraft‐borne detector would observe. We concentrate on the effects of purely transverse electromagnetic signals. The time scale of a particle's motion relative to the wave period is shown to determine the nature of its response. For low‐energy particles, the acceleration in the last gyroperiod before detection is what matters. At higher energies, what has occurred over recent bounce and drift motions becomes increasingly important and convection of gradients by the wave E × B drift must be considered. Distinguishing features such as phase differences between signals in back‐to‐back detectors or between channels of different energy are catalogued. In particular, we assess the detectability of resonance effects in the light of detector characteristics and finite signal bandwidth. Recent observations are used to illustrate the ideas developed.

Turbulent particle dispersion in an electrostatic precipitator

Ultralow frequency (ULF) electromagnetic waves in Earth's magnetosphere can accelerate charged particles via a process called drift resonance. In the conventional drift resonance theory, a default assumption is that the wave growth rate is time independent, positive, and extremely small. However, this is not the case for ULF waves in the real magnetosphere. The ULF waves must have experienced an earlier growth stage when their energy was taken from external and/or internal sources, and as time proceeds the waves have to be damped with a negative growth rate. Therefore, a more generalized theory on particle behavior during different stages of ULF wave evolution is required. In this paper, we introduce a time‐dependent imaginary wave frequency to accommodate the growth and damping of the waves in the drift resonance theory, so that the wave‐particle interactions during the entire wave lifespan can be studied. We then predict from the generalized theory particle signatures during different stages of the wave evolution, which are consistent with observations from Van Allen Probes. The more generalized theory, therefore, provides new insights into ULF wave evolution and wave‐particle interactions in the magnetosphere.

The study of nuclear reactions and interactions in plasmas has recently assumed great importance because of its connection with processes such as laser-driven ion acceleration and nuclear fusion for massive energy production. In fact, the extremely high electron densities established in the plasma bring to different behaviour of charged particles with respect to that observed when a stable beam impinges on a solid target. Ion stopping power in cold matter is relatively well known and has been characterized with the help of a large set of experimental data and theoretical studies; on the contrary a lot of open questions remain when it comes to ions stopping in a plasma, especially in the energy domain where the projectile ion velocity approaches that of free plasma electrons. The main aim of this work is a systematic and careful measurement of stopping power for several ions versus plasma parameters, especially in the region of thermal velocities, where the energy deposition should depend strongly on plasma temperature, density and ionization fraction. The plasma will be generated under vacuum, by interaction of a laser beam with a solid target. Plasma plume will be characterized in temperature and density by optical and X-ray diagnostics; simultaneously the energy loss will be measured for an ion microbeam crossing the plume. This contribution provides an overview of the experimental technique and the results obtained during first tests for the characterization of experimental apparatus.

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Two-dimensional nonlinear dynamics of an axially moving viscoelastic beam with time-dependent axial speed

Intramolecular (13)C kinetic isotope effects were determined for the dimerization of methacrolein. Trajectory studies accurately predict the isotope effects and support an origin in Newton's second law of motion, with no involvement of zero-point energy or transition state recrossing. Atomic motion reaction coordinate diagrams are introduced as a way to qualitatively understand the selectivity.

Bubble size distributions (BSDs) near a reference electrode (RE) in aqueous glycerol solutions of an electrolyte NaCl have been investigated under various gas superficial velocities (Us). BSD and voltage reading of the solution were measured by using a high-speed digital camera and a pH/voltage meter, respectively. The results show that bubble size (b) increases with liquid viscosity (μc) and Us. Self-similarity is seen and can be described by the log-normal form of the continuous number frequency distribution. The result shows that b controls the voltage reading in each solution. As b increases, the voltage increases because of gas bubbles interrupting their electrolyte paths in the solutions. An analysis of bubble rising velocity reveals that Stokes' Law should be used cautiously to describe the system. The fundamental equation for bubble formation was developed via Newton's second law of motion and shown to be the function of three dimensionless groupsWeber number, Bond number, and Capillary number. Af...

The equation F = ma, shorthand for Newtion's second law of motion, is the 1 + 1 = 2 of classical mechanics. The equation seems obvious and straightforward. It appears simply to translate an ordinary experience into measurable terms: push something and it moves.