Hybrid stars from a constrained equation of state

We determine, within a meta-model, the properties of the nuclear matter equation of state (EoS) that allow for a phase transition to deconfinement matter. It is shown that the properties that define the isoscalar channel are the ones that are affected, in particular, a phase transition implies much larger values of the skewness and kurtosis. The effect of multi-quark interaction channels in the description of the quark phase in hybrid stars is also studied. NS properties, such as the mass and radius of the quark core, show an interplay dependence between the 8-quark vector and the 4-quark isovector-vector interactions. We show that low mass NS, M ~ 1.4M⊙, may already contain a quark core, and satisfy all existing NS observational constraints. We discuss the strangeness content of the quark core and its influence on the speed of sound.

Effect of the variable gear mesh model in dynamic simulation of a drive train in the wind turbine

To acquire transient response of a drive train, we consider more detailed mathematical model including variable gear mesh. The gear mesh is represented by the Fourier series. In transient analysis, gear’s angular velocity is considered as constant. It makes sense when we consider steady-state. However, the gear mesh is the only part which vary according to angular displacement. It should be considered not only by the Fourier series model but also as a modified system displacement. To establish the gear mesh model, we use a curve fitting theorem. Equations of motion are derived by the Lagrange’s equation, constrained equation and gear relation. The equations are solved by numerical integration method, the Newmark method. Through these processes, we get dynamic results including angular displacement, velocity, acceleration, gear mesh contact forces. Also, the Fourier transform is used to see signals more detailed. At last, we compared the variable gear mesh and constant gear mesh, gave physical meaning, and analyzed cause of the phenomenon.

A theory of particle physics about quantum number constrained equation and particle singularity

In this paper, two fundamental problems of particle physics are studied theoretically. The first one is: to solve the problem of establishing general quantum number constrained equation, the symmetry transformation mechanism of charge eigenstates for elementary particles is adopted, and the quantum number constrained equation is established, which is applicable to physical particles. For hadrons, this equation is completely consistent with Gell-Mann-Nishijima formula. For leptons, the lepton quantum numbers are exactly the solutions of this equation. The second one is: to solve the problem of understanding singularity and calculating singular numbers, a hypothesis that a composite particle may has virtual structure is proposed. According to this hypothesis, the singular particles must be composite particles, and have virtual structures. In a virtual structure, the particles and antiparticles of component particles can form particle-antiparticle pairs, which have great influence such as improving mass and changing life of composite particles. Therefore, the composite particle with particle-antiparticle pairs in its virtual structure is singular particle, and the singular number is the number of particle-antiparticle pairs. These two theoretical results are in good agreement with the already achieved experimental results of particle physics, can explain the related phenomena of physical particles from a deeper physical mechanism, and theoretically predict the existence of singular leptons and several new singular hadrons.

Parameter Optimization Method for Identifying the Optimal Nonlinear Parameters of a Miniature Transducer with a Metal Membrane

This study proposes a parameter optimization method for identifying the optimal nonlinear parameters of a miniature transducer with a metal membrane. Specifically, a nonlinear lumped parameter model (LPM) of a miniature transducer that accounts for predicted displacement in a manner that is consistent with the displacement measured by a high-precision capacitance micro-displacement sensor is proposed. To avoid application of the proposed optimization method to an ill-posed problem, this paper proposes a constrained equation that is derived from the relationships of nonlinear parameters. The Broyden–Fletcher–Goldfarb–Shanno (BFGS) algorithm is used to minimize the objective function in order to obtain an appropriate solution from the proposed nonlinear LPM. The numerical simulation results and a discussion of the experiments are presented. The numerical simulation verification demonstrated that the presented method can estimate the suitable nonlinear parameters for the displacement with errors. With regard to empirical verification, the empirical investigations showed that the proposed method could accurately assess the nonlinear parameters of a miniature transducer with a metal membrane.

Systems Errors Identification Method of Hull Deformation Data Based on Total Variation Constrained

Based on the analysis of influence factors for hull deformation data, physical models including hull curve deformation, hull torsion deformation and hull athletics deformation were established according to mechanical principle. Considering characteristics of the space instrumentation ship, systems errors identification method based on total variation constrained was provided. First order differential coefficient of deformation data was joined in a constrained equation in the method. Systems errors coefficient and exact value of deformation data were solved through alternating iterations. The simulation result of deformation measured data indicated that identification errors were in consistent with plus errors, and systems errors coefficient was also estimated accurately. This demonstrated that the proposed method is suitable for systems errors identification of hull deformation data.

Hamel Paradox and Rosenberg Conjecture in Analytical Dynamics

Hamel proposed a seemingly intuitive, simple, straightforward, but incorrect, method of formulating the constrained equation of motion. The method has to do with the direct embedding of the constraint into the kinetic energy of the unconstrained motion. His intention was to caution against its possible adoption. Rosenberg echoed Hamel's warning and followed up to explore more insight of this method. He proposed a conjecture that the Hamel's embedding method would work if the constraint was holonomic. It would not work if the constraint was nonholonomic. We investigate the Hamel paradox and Rosenberg conjecture via the use of the Fundamental Equation of Constrained Motion.