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The comments provided in this document are a response to a study conducted by Professor Jean-Pierre Pascal on the inertia forces in roller test rigs. The comments address concerns raised by Professor Pascal regarding a statement made in a previous paper. The comments highlight the limitations of using roller test rigs for longitudinal wheelset motion and emphasize the need for three-dimensional models to accurately capture the effects of inertia forces on contact forces. The document also points out several fundamental problems with the planar example used in Professor Pascal's paper. Overall, the comments suggest that further research is needed to fully understand the impact of longitudinal velocity on motion trajectories and contact forces. [Extracted from the article]

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper assesses thermoelastic damping (TED) in circular nanoplates by incorporation of the small-scale effect into structural and thermal domains. The nonlocal elasticity theory and dual-phase-lag (DPL) heat conduction model are exploited for achieving the size-dependent coupled thermoelastic equations. By choosing time-harmonic and asymmetric form for deflection and temperature change, and solving the size-dependent thermoelastic eigenvalue problem, the damped natural frequency of circular nanoplate is extracted. On the basis of the complex frequency approach, an analytical relation, for the description of TED in circular nanoplates, is derived. For different boundary conditions and vibration modes, a comparison study is performed between the size-dependent results and those provided by classical continuum mechanics and heat conduction theories. Outcomes show a discrepancy between results acquired by the size effect on the structure and heat conduction. It is elucidated that how nonlocal and DPL characteristic parameters can represent the size-dependent phenomenon and can affect the magnitude of TED. A comprehensive parametric study is conducted to specify the influence of boundary constraints, vibration mode and the type of material on the amount of energy loss from TED. [ABSTRACT FROM AUTHOR]

Friction is not an inherent attribute in natural science. Indeed, there are various friction phenomena present in social systems. In this study, the researchers developed the general concept of social friction and distinguished the two-dimensional structure of explicit-implicit social friction phenomena. Specifically, explicit friction includes institutional friction, economic friction, behavioral friction, and migration friction. Implicit friction includes cultural friction, cognitive friction, interpersonal friction, technological friction, and information friction. Physical theories such as friction force, classical mechanics, and functional principles have been introduced to construct a social friction force model. This paper describes the emergence and evolution of social friction phenomena from the mechanics perspective and clarifies the various characteristics of social friction force in different areas. This study also provides a new theoretical perspective for examining social friction phenomena and adds innovative content to intersection studies in physics and the social sciences. [ABSTRACT FROM AUTHOR]

Purpose: In this paper, the standard Peridynamic Timoshenko beam model accounting for the shear deformation is chosen to describe the thick beam kinematics. Unfortunately, when applied to very thin beam structures, the standard Peridynamics (PD) encounters the shear locking phenomenon, leading to incorrect solutions. Design/methodology/approach: PD differs from classical continuum mechanics and other nonlocal theories that do not involve spatial derivatives of the displacement field. PD is based on the integral equation instead of differential equations to handle discontinuities and other singularities. Findings: The shear locking can be successfully alleviated using the developed selective integration method. In particular, this technique has been implemented in the standard PD, which allows an accurate result for a wide range of slenderness from very thin to thick (10 < L/t < 103) structures. It can also accelerate the computational time for particular dynamic problems using fewer neighboring integration particles. Several numerical examples are solved to demonstrate the effectiveness of the proposed method for modeling beam structures. Originality/value: The paper highlights the severe shear locking phenomenon in the Peridynamic Timoshenko beam available in the literature, especially for very thin structures. A new alternative for the alleviation of shear locking in the Peridynamic Timoshenko beam, using selective integration. Hence the developed Peridynamic Timoshenko beam model is effective for thin and thick structures. A new peridynamic formulation for the low-velocity impact beam models is presented and validated. Highlights: The paper highlights the severe shear locking phenomenon in the Peridynamic Timoshenko beam proposed in the literature, especially for very thin structures. The developed Peridynamic Timoshenko beam model based on selective integration is effective for thin and thick structures. A new peridynamic formulation for the low-velocity impact beam models is presented and validated. [ABSTRACT FROM AUTHOR]

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Physics is a tricky subject to learn, especially when it comes to students applying physics knowledge to the real world and its application. This paper aims to study the effectiveness of the integrated science, technology, engineering, and mathematics project-based learning (iSTEM-PjBL) module in physics on students’ belief-specific categories, i.e., real-world connection, conceptual connection and applied conceptual understanding. This research used the quasi-experimental model, employing a two-group pre-survey-post-survey design. Quantitative data were collected using the Colorado Learning Attitude about Science Survey (CLASS) instrument at two selected schools in Sabah, Malaysia, and Seoul, Korea. The sample size was 88 from Malaysia and 66 from Korea who learned classical mechanics. The students were divided into two groups, respectively, i.e., the experimental group (Malaysia=44, Korea=33) and the control group (Malaysia=44, Korea=33). Participants in the experimental group were intervened with the integrated STEM-PBL physics module, whilst participants in the control group learned physics through a conventional approach for eight weeks. Participants in both groups were then administered a pre-survey before and post-survey after the intervention. This research showed that the integrated STEM-PjBL physics module significantly improved students’ real-world connections, conceptual connections, and applied connections after the intervention. The implications and suggestions were also discussed to extend the research further. [ABSTRACT FROM AUTHOR]

There is a fundamental subsets–partitions duality that runs through the exact sciences. In more concrete terms, it is the duality between elements of a subset and the distinctions of a partition. In more abstract terms, it is the reverse-the-arrows of category theory that provides a major architectonic of mathematics. The paper first develops the duality between the Boolean logic of subsets and the logic of partitions. Then, probability theory and information theory (as based on logical entropy) are shown to start with the quantitative versions of subsets and partitions. Some basic universal mapping properties in the category of S e t s are developed that precede the abstract duality of category theory. But by far the main application is to the clarification and interpretation of quantum mechanics. Since classical mechanics illustrates the Boolean worldview of full distinctness, it is natural that quantum mechanics would be based on the indefiniteness of its characteristic superposition states, which is modeled at the set level by partitions (or equivalence relations). This approach to interpreting quantum mechanics is not a jury-rigged or ad hoc attempt at the interpretation of quantum mechanics but is a natural application of the fundamental duality running throughout the exact sciences. [ABSTRACT FROM AUTHOR]

A two-axis stabilizing gimbal is a device that ensures a sensor is working properly on a moving platform. When classical mechanics (Newton–Euler and Lagrange) is employed to model a two-axis stable gimbal, its limitations can complicate the modeling process. To address this issue, a method for establishing a dynamic model for a two-axis stabilizing platform based on the Kane method is proposed in this paper. The Kane method offers the advantage of a simple model structure and computational efficiency. Initially, utilizing a generalized coordinate system, expressions of the generalized velocities, deflection velocities and angular velocities are derived. Subsequently, the generalized active forces and inertial forces acting on the two-axis stabilized gimbal are analyzed. Finally, by combining force and velocity with the Kane equation, the dynamic model of the two-axis stable platform is obtained, demonstrating the validity of the Kane method for establishing the two-axis stable platform model. To ensure the pointing accuracy stability of the two-axis stabilizing platform, a Novel Particle Swarm Optimization Proportion Integration Differentiation (NPSO-PID) controller is designed using the PSO algorithm. It is then simulated in MATLAB/Simulink and compared with a classical PID controller. Simulation results demonstrate that NPSO-PID exhibits superior object tracking performance compared to classical PID controllers and better optimization of control parameters compared to traditional PSO-PID controllers. [ABSTRACT FROM AUTHOR]

Conical intersection (CI) leads to fast electronic energy transfer. However, Hamm and Stock [Phys. Rev. Lett. 109, 173201 (2012)] showed the existence of a vibrational CI and its role in vibrational energy relaxation. In this paper, we further investigate the vibrational energy relaxation using an isolated model Hamiltonian system of four vibrational modes with two distinctively different timescales (two fast modes and two slow modes). We show that the excitation of the slow modes plays a crucial role in the energy relaxation mechanism. We also analyze the system from a mixed quantum-classical (surface hopping method) and a completely classical point of view. Notably, surface hopping and even classical simulations also capture fast energy relaxation, which is a signature of CI's existence. [ABSTRACT FROM AUTHOR]

The thermal counterflow of superfluid helium past a cylinder has been found to generate two pairs of symmetrical vortexes upstream and downstream of the cylinder in experiments. This is a unique physical phenomenon that differs from classical fluids. In this paper, we have developed a new solver on the OpenFOAM® platform based on the simplified two-fluid model proposed by Kitamura et al. and use it to simulate the thermal counterflow phenomenon. The numerical simulation results obtained by the simplified two-fluid model agree well with the experimental results. Based on this numerical simulation, an investigation has been carried out into the evolution of the four-vortex structure of the superfluid helium thermal counterflow. This paper supports the conjecture of many researchers that large scale quantum turbulence in superfluid helium can be explained using classical mechanics. Details of the theoretical basis, the solver computational procedure, the numerical simulation results, and the discussion based on the results are presented in this paper. [ABSTRACT FROM AUTHOR]

For many students, learning physics is difficult because of its abstractness. To help students to learn physics, we have developed the Integrated Science, Technology, Engineering, and Mathematics Projects Based Learning (STEM-PjBL) method based on principles from neuroscience. We believe that incorporating principles from educational neuroscience would help students learn better. This paper describes our experiments of implementing the integrated STEM-PjBL Module in physics, i.e., classical mechanics, to secondary school students in Malaysia and South Korea. The study consists of two groups of students: the experiment group, 77 in total, comprising those who have undergone the integrated STEM-PjBL, and the control group, again 77 in total, who experienced the traditional approach. The Colorado Learning Attitudes Science Survey (CLASS) was conducted for the two groups on students' beliefs about physics and learning physics before and after the implementation. The paired sample t-test from the pre-survey and post-survey shows that the integrated STEM-PjBL group has a more positive shift in belief about physics and learning physics than the traditional group. The results of the independent samples t-test for students' beliefs about physics and learning physics, compared with the postsurvey between the experimental group and the traditional group for both Malaysian and Korean perspectives, show that the experimental group has a higher mean compared to the traditional group. This paper explains why the integrated STEMPjBL has improved students' beliefs about physics and learning physics, from the neuroscience education perspective. Finally, the paper concludes with guidelines for teachers who wish to implement the integrated STEM-PjBL in the classroom. [ABSTRACT FROM AUTHOR]

This paper investigates the structural changes in the turbulent motion of an incompressible fluid in the hydrodynamic entrance region of plane-parallel pressure motion. Movement in pressure hydromechanical systems usually occurs in a turbulent regime. Studying the patterns of changes in hydrodynamic parameters under conditions of stationary turbulent pressure motion in the inlet region is a very urgent task. The study was carried out on the basis of boundary layer equations. Taking into account the dependence of changes in the kinematic viscosity coefficient that occur between layers of fluid, a boundary value problem was formed. Analytical solutions have been obtained that make it possible to obtain patterns of changes in velocity and pressure in any effective flow section. Based on the general conclusions of the study, solutions were found for two cases: a) the velocity of the fluid entering the cylindrical pipe is constant; b) the velocity of the incoming fluid has a parabolic distribution. For these cases, using computer analysis of the data obtained, general graphs of velocity changes were constructed in various sections along the hydrodynamic entrance region. These graphs, which display the change in velocity along the entire length of the inlet, make it possible to obtain the velocity of fluid movement at any point along the inlet length and estimate the length of the transition zone. The results obtained are among the least studied issues of classical fluid mechanics and are of important theoretical interest. The results obtained are applicable for the correct construction of the hydrodynamic entrance region of machinery. A calculation formula has been obtained to determine the length of the hydrodynamic inlet region. [ABSTRACT FROM AUTHOR]

This paper focuses on Kojève's account of history and philosophy of science. Kojève's understanding of science can be characterized as internalism, which is evident in his holistic view of philosophy, theology, quantum physics, and the history of classical Newtonian mechanics. It precipitates the facilitation of a further inquiry into the Christian genesis, secular evolution, and subsequent de-Christianization of scientific thought. The paper includes a critical scrutiny of Kojève's philosophical tenets, followed by a comparative analysis of the views of Hegel, Koyré, and Kojève. The primary objective of this research is to juxtapose Kojève's doctrines with Hegel's contemplations on the history and philosophy of science. In addition to identifying affinities, notably the emphasis on the Christian concept of God's Incarnation for the advancement of science, I draw the distinctions between the positions of Hegel, Kojève, and Koyré, specifically concerning the valuation of mathematical knowledge. [ABSTRACT FROM AUTHOR]

Applied physics and computer methods in biomechanics have been extensively used in sports science research, including performance and biomechanics analysis. The Brachistochrone problem, which expresses the curve that an object draws quickly under gravitational forces in a vertical position, is one of the most widely used studies in classical mechanics. A similar problem arises when a badminton player intends to hit a smash with the shortest shot time. This paper aims to determine the optimal stroke trajectory for a shuttlecock smash in the shortest time. We simulate the badminton smash movement using a computer program after analyzing the shuttlecock smash analytically and numerically for several conditions. The modeling results show that a cycloid trajectory allows badminton players to smash the shuttlecock in the shortest time. Based on the experimental findings of Tsai, Huang, and Jih's study and our models, the ratio of clear speed to smash speed is 0.75, which is still in the range of 0.71 to 0.76, and we find that a cycloid trajectory gives the shortest shuttlecock smash time. We concluded that the experimental data from this study's literature supported our model. The novelty of this study is that we found the first powerful model and simulation of conventional Brachistochrone in the case of a badminton smash of badminton players. For badminton coaches and players, this model formulation is intended as a reference for optimizing shuttlecock shots. Furthermore, another novelty of this research is that it may lead to software that can be used to analyze the muscle strength of badminton players based on their cycloid hand trajectory and shuttlecock speed. [ABSTRACT FROM AUTHOR]

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, we discuss mechanical systems with inequality constraints Φ (q , q ˙ ,...) ≤ 0 . We demonstrate how such constraints can be taken into account by proper modification of the action which describes the original unconstrained dynamics. To illustrate this approach, we consider a harmonic oscillator in the model with limiting velocity. We compare the behavior of such an oscillator with the behavior of a relativistic oscillator and demonstrate that when the amplitude of the oscillator is large, the properties of both types of oscillators are quite similar. We also discuss inequality constraints, which contain higher derivatives. At the end of the paper, we briefly discuss possible applications of the developed approach to gravity models with limiting curvature. [ABSTRACT FROM AUTHOR]

In Paper I of this series, the elastic collision was described via simultaneous processes, where the energy is conserved at any moment. In this paper, we critically review the kinetic theory of gases, which was developed based on Newtonian mechanics, and show that it violates the principle of the conservation of energy. By placing the energy conservation at the beginning of the deductive formalism, we derive the ideal gas law via equally strong simultaneous counter-processes at the walls, namely, momentum work and volume work. Several new insights into the state variables of an ideal gas are obtained: (i) pressure cannot be expressed via the kinetic energy of an ideal gas, and (ii) temperature can be interpreted as a particle-related (microscopic) state variable. The historical choice to set a zero point of the potential energy for a confined ideal gas needs to be corrected, and the internal energy of an ideal gas turns out to include more forms of energy than specified in the kinetic theory of gases. Finally, and importantly, we show that the process approach to an ideal gas and thus to collisions is experimentally confirmed. [ABSTRACT FROM AUTHOR]

The generalized Reissner-type operator of three-dimensional micropolar mechanics of solids is presented, on the basis of which the generalized Reissner-type operator of three-dimensional micropolar mechanics of thin solids with one small size is obtained under the new parameterization of the domains of these bodies. From the last Reissner-type operator, in turn, the generalized Reissner-type variational principle of three-dimensional micropolar mechanics of thin solids with one small size is derived under the new parametrization of the domains of these bodies. It should be noted that the advantage of the new parameterization is that it is experimentally more accessible than other parameterizations (Nikabadze in Development of the method of orthogonal polynomials in the classical and micropolar mechanics of elastic thin bodies, MSU Publishing House, 2014; Contemp Math. Fundam Dir 55:3–194, 2015; J Math Sci 225:1, 2017). Further, applying the method of orthogonal polynomials (expansion of unknown quantities in series in terms of a system of orthogonal polynomials), from the generalized Reissner-type variational principle of three-dimensional micropolar mechanics of thin solids with one small size under the new parameterization of the domains of these bodies, the Reissner variational principle of micropolar mechanics of thin solids with one small size in the moments with respect to the system of Legendre polynomials is derived. In addition, the method is described for obtaining the variational principles of Lagrange and Castigliano of micropolar mechanics of thin solid with one small size under the new parametrization of the domains of these bodies in moments with respect to systems of the first and second kind Chebyshev polynomials. The paper is a continuation of the work "Nikabadze, Ulukhanyan, On some variational principles in the three-dimensional micropolar theories of solid"; therefore, before reading this paper, the authors invite the interested reader to familiarize themselves with the work (Nikabadze and Ulukhanyan in On some variational principles in the three-dimensional micropolar theories of solids, submitted). [ABSTRACT FROM AUTHOR]

Nominated for the Eurosteel 2021 Best Paper Award This short report has been prepared in the context of the Eurosteel 2021 Best Paper Award. It summarizes developments completed and in progress at the University of Liège designed to characterize the complete shear behaviour of the panel zone in steel beam‐to‐column joints in terms of stiffness, resistance and ductility. This work is part of a larger research project which aims to predict the complete rotational response of the joint to failure. [ABSTRACT FROM AUTHOR]

This document is a special issue of AIMS Materials Science focused on peridynamics and its applications. Peridynamics is a new formulation of continuum mechanics that overcomes the limitations of classical continuum mechanics. It uses integro-differential equations to represent material points and does not rely on spatial derivatives. This makes it particularly useful for analyzing cracks and representing material behavior that cannot be properly defined in classical continuum mechanics. The special issue includes six journal papers that cover topics such as fractional peridynamic mechanics, dynamic fracture, structural analysis, and optimization of reinforced concrete beams. [Extracted from the article]

The Thematic Einstein Semester was financially supported by the Einstein Foundation Berlin through the Berlin Mathematics Research Center MATH+ and organized by Matthias Liero (Weierstrass Institute Berlin), Volker Mehrmann (Technische Universität Berlin), Alexander Mielke (Weierstrass Institute Berlin and Humboldt-Universität zu Berlin), Dirk Peschka (Weierstrass Institute Berlin), Marita Thomas (Weierstrass Institute and Freie Universität Berlin), Barbara Wagner (Weierstrass Institute Berlin). Hypocoercivity and controllability in linear semi-dissipative Hamiltonian ordinary differential equations and differential-algebraic equations by Franz Achleitner, Anton Arnold, and Volker Mehrmann The authors discuss new stability and hypocoercivity results of finite-dimensional linear time-invariant semi-dissipative Hamiltonian ordinary differential and differential-algebraic equations. This special issue was initiated during the Thematic Einstein Semester "Energy-Based Mathematical Methods for Reactive Multiphase Flows" that took place from October 2020 to February 2021 during the corona pandemic. [Extracted from the article]

The drift velocity of a particle under a driving force has its roots in the theory of electrical conduction. Although it has been studied for over 100 years, it still yields surprises. At the heart of a particle's drift velocity is an interplay of classical, quantum, and statistical mechanics. Irreversibility and energy loss have been assumed as essential features of drift velocities and very little effort has been made to isolate the aspects of particle transport that are due to elastic mechanisms alone. In this paper, we remove energy loss and quantum mechanics to investigate the classical and statistical factors that can produce a drift velocity using only elastic scattering. A Monte Carlo simulation is used to model a particle in a uniform force field, subject to randomly placed scatterers. Time-, space-, and energy-dependent scattering models, with varied ranges of scattering angles, are investigated. A constant drift velocity is achieved with the time scattering model, which has a constant average time between scattering events. A decreasing drift velocity is observed for space and energy-dependent models. The arrival of a constant drift velocity has to do with a balance of momentum gained between collisions and momentum lost after a collision. [ABSTRACT FROM AUTHOR]

The ordinary state-based peridynamics (OSB PD) model is an integral nonlocal continuum mechanics model. And the three-dimensional OSB PD model can deal with linear elastic solid problems well. But for plane problems, the calculation results of existing models have large deviations. In this paper, a set of OSB PD models for plane problems is established by theoretical derivation. First, through the strain energy density function equivalence of peridynamics and classical continuum mechanics, the equivalent coefficients of the plane strain and plane stress problems of OSB PD are deduced. Then, consider the cantilever beam deformation simulation under concentrated load. The simulation results show that the maximum displacements are in good agreement with the corresponding analytical solutions in all directions. Finally, in the simulation of the slab with a hole, the two cases of uniform displacement and uniform load are considered, respectively. The simulation results are consistent with the ANSYS analysis results, and the deviation is small, which verifies the validity of the model. [ABSTRACT FROM AUTHOR]

This paper incorporates schematic concepts related to mental inertia and provides an avenue for interpreting psychology using the principles of classical mechanics. Schemas find wide application in diverse fields, ranging from ergonomics to psychotherapy. Nonetheless, it is crucial to incorporate schemas themselves into a more unified and comprehensive theoretical framework. Drawing upon the free energy principle (FEP) and the second law of thermodynamics, it is evident that humans possess a natural inclination to construct and maintain consistent cognitive structures. This characteristic contributes to the stability of schemas within a defined range. The particular scope of the model is closely intertwined with its structure, leading to variations among individuals in diverse environments. The coherence of the schema within a defined range can be perceived as the magnitude of mental inertia. This psychological analogy emphasizes the importance of considering the influences exerted by the external environment and their effects on mental inertia when predicting the human mind and behavior. [ABSTRACT FROM AUTHOR]

This paper develops a general form of Gauss's Principle of Least Constraint, which deals with the manner in which Nature appears to orchestrate the motion of constrained mechanical systems. The theory of constrained motion has been at the heart of classical mechanics since the days of Lagrange, and it is used in various areas of science and engineering like analytical dynamics, quantum mechanics, statistical physics, and nonequilibrium thermodynamics. The new principle permits the constraints on any mechanical system to be inconsistent and shows that Nature handles these inconsistent constraints in the least squares sense. This broadening of Gauss's original principle leads to two forms of the General Gauss Principle obtained in this paper. They explain why the motion that Nature generates is robust with respect to inaccuracies with which constraints are often specified in modeling naturally occurring and engineered systems since their specification in dynamical systems are often only approximate, and many physical systems may not exactly satisfy them at every instant of time. An important byproduct of the new principle is a refinement of the notion of what constitutes a virtual displacement, a foundational concept in all classical mechanics. [ABSTRACT FROM AUTHOR]

Purpose: Considering the size-dependent influence ignored by classical continuum mechanics, a new non-classical Euler–Bernoulli beam model is proposed in this paper. The new fractional viscoelastic nanobeam model is set up using the fractional Kelvin–Voigt viscoelastic model and Hamilton's principle. And the new model studies the total effects of nonlocal elasticity, modified couple stress, and surface energy. Methods: The model represented the fractional integral-partial differential governing equation is solved by Galerkin's and predictor–corrector methods. First, the effects of nonlocal elasticity, modified couple stress, surface energy, and their coupling impact on the nonlinear time response of free vibration of fractional viscoelastic nanobeam are analyzed. Then, in the frame of nonlocal couple-stress elasticity and surface energy theory, the effects of different parameters on the nonlinear time responses of free and forced vibration of fractional viscoelastic nanobeam are discussed. Results and Conclusion: The numerical results show that the fractional order must be considered in the modeling of viscoelastic nanobeam, and the system's damping enhances by the increase of fractional order. Moreover, owing to the correlation between fractional order and excitation frequency, the nonlinear time responses of fractional order to free and forced vibration are different. [ABSTRACT FROM AUTHOR]

This paper analyzes classical and quantum physical systems from an optimal control perspective. Specifically, we explore whether their associated dynamics can correspond to an open- or closed-loop feedback evolution of a control problem. Firstly, for the classical regime, when it is viewed in terms of the theory of canonical transformations, we find that a closed-loop feedback problem can describe it. Secondly, for a quantum physical system, if one realizes that the Heisenberg commutation relations themselves can be considered constraints in a non-commutative space, then the momentum must depend on the position of any generic wave function. That implies the existence of a closed-loop strategy for the quantum case. Thus, closed-loop feedback is a natural phenomenon in the physical world. By way of completeness, we briefly review control theory and the classical mechanics of constrained systems and analyze some examples at the classical and quantum levels. [ABSTRACT FROM AUTHOR]

This paper shows how key aspects of Aristotle’s core concepts of matter and motion, some of which have recently been shown to help make sense of quantum mechanical indeterminacy, align with some important results of the energy-momentum relationship of special relativity. In this conception, mobility and indeterminacy are inherently linked to each other and to materiality. Applying these ideas to massless particles, which relativity tells us move at the maximal cosmic speed, allows us to draw the conclusion that they must be the most basic physical bodies, that is, mobile substances (secondary, locomotive matter). The most familiar massless particle, the photon, constitutes light. Furthermore, because the photon composes luminous matter but cannot be decomposed into anything else more basic, it fulfills the definition of element. [ABSTRACT FROM AUTHOR]

In this paper, some properties of resonances for multi-dimensional quantum walks are studied. Resonances for quantum walks are defined as eigenvalues of complex translated time evolution operators in the pseudo momentum space. For some typical cases, we show some results of existence or nonexistence of resonances. One is a perturbation of an elastic scattering of a quantum walk which is an analogue of classical mechanics. Another one is a shape resonance model which is a perturbation of a quantum walk with a non-penetrable barrier. [ABSTRACT FROM AUTHOR]

In this paper, I show that the generally accepted methods of classical mechanics are not applicable for calculating the outer parts of the rotation curves (RCs) of galaxies, where the influence of collisions on gas dynamics becomes dominant. In addition, the hydrodynamic approach cannot be used for this purpose due to an extreme rarefaction of the gas. I develop a new approach for describing the gas dynamics in outer regions of galactic disks, where the gas dynamics is determined mainly by collisions. Equations (free from restrictions imposed on hydrodynamics) are obtained that describe the dynamics of rarefied gas. The resulting equation D n 1 R 0 ∂ n ∂ r = − (V d ⊥ V ⊥ tot ) (14) relates two quantities: the tangential velocity of the gas as a function of the distance from the center of a galaxy (RC) and the radial distribution of the gas density. It is shown that if the physical properties of the rarefied gas are properly taken into account, then dark matter (DM) is not required, and the "nonphysical" (non-Keplerian) RCs of the outer parts of the galactic disks are tailwinds that can be described within the framework of conventional gas kinetics. To illustrate the correctness of the obtained model, two galaxies with flat RCs (NGC7331 and NGC3198) are considered. From the observed RCs, using Eq. (14), the radial densities of the gas are calculated. An excellent agreement was obtained between the calculated gas densities and their observed values, which is a serious argument in favor of the developed model. Thus, the nonphysical RCs of spiral galaxies represent the tailwinds of gas, the dynamics of which is naturally described by the kinetic equation without involving the concept of DM. Total masses of two galaxies NGC7331 and NGC3198 have been calculated. Implications for cosmology are discussed. [ABSTRACT FROM AUTHOR]

This paper presents a new conceptualization of complex nonlinear mechanical systems and develops new and novel computational methods for determining their response to given applied forces and torques. The new conceptualization uses the idea of including particles of zero mass to describe the dynamics of such systems. This leads to simplifications in the development of their equations of motion and engenders a straightforward new computational approach to simulate their behavior. The purpose of the paper is to develop a new analytical and computational methodology to handle complex systems and to illustrate it through the study of an old unsolved problem in classical mechanics, that of a non-uniform rigid spherical shell rolling, without slipping, under gravity on an arbitrary dimpled bowl-shaped rigid surface. The new conceptualization provides the explicit equations of motion for the system, the analytical determination of the reaction forces supplied by the surface, and a straightforward computational approach to simulate the dynamics. Detailed analytical and numerical results are provided. The computations illustrate the complexity of the dynamical behavior of the system and its high sensitivity to the initial orientation of the shell and to the presence of any initial angular velocity normal to the surface. [ABSTRACT FROM AUTHOR]

This paper proposes a novel approach to quantizing Nambu brackets in classical mechanics using operator formalism. The approach employs the "Planck derivative" to represent Nambu brackets, from which we derive a commutation relation for their quantization. Notably, this commutation relation aligns with that emerging from the T-duality of closed strings in a twisted torus with a B-field, thereby hinting at a potential connection with double field theory. [ABSTRACT FROM AUTHOR]

Previous work treated the problem of a mass sliding over a rough spherical surface in broad generality, providing both analytic and numerical solutions. This paper examines special cases of 2D motion along a surface meridian when the initial speed is precisely chosen so that the sliding mass nearly stops before speeding up and subsequently leaving the surface. Carrying the solution for these critical cases into the time domain via both an analytical method and numerical integration adds richness that might otherwise be missed. The numerical method raises practical mathematical issues that must be handled carefully to obtain accurate results. Although conceptually simple, this classical mechanics problem is an excellent vehicle for students to gain proficiency with mathematical analysis tools and further their appreciation for how applied mathematics can bring new insight into situations where intuition may fall short. [ABSTRACT FROM AUTHOR]

Multiparty quantum private comparison (MQPC) protocol enables the comparison of the private information of n parties through the combination of quantum mechanics with classical private comparison. In order to improve efficiency and practicality, this paper proposes an efficient MQPC protocol based on single photons and rotation encryption with the assistance of a semi-honest third party (TP). TP participates in preparing the initial single photon sequence, which is encrypted and sent to the participants one by one. The private inputs of participants are encoded into particular rotation angles that are used to convert the received single photon sequence to an unknown quantum state sequence, which is returned to TP in a closed-loop transfer mode. By implementing rotation encryption and multiplexing of single photons, the qubit efficiency and practicality of the protocol can be significantly improved, without the need for complex quantum technologies, such as entanglement swapping of high-dimensional quantum states, maximal entanglement states with n-particle and entanglement correlation between various particles in a quantum state. Moreover, the proposed protocol is simulated on IBM Quantum Experience to show its feasibility. Security analysis demonstrates that the proposed protocol is resistant to different types of attacks. [ABSTRACT FROM AUTHOR]

This paper proposes a theory that bridges classical analytical mechanics and nonequilibrium thermodynamics. Its intent is to derive the evolution equations of a system from a stationarity principle for a suitably augmented Lagrangian action. This aim is attained for homogeneous systems, described by a finite number of state variables depending on time only. In particular, it is shown that away from equilibrium free energy and entropy are independent constitutive functions. [ABSTRACT FROM AUTHOR]

The well-known narrow and intense optical absorption J-band was discovered experimentally by Jelley and independently Scheibe in 1936. In 1938, Franck and Teller, associating the appearance of the J-band with the formation of molecular J-aggregates, gave a theoretical explanation for the J-band based on the Frenkel exciton model. This explanation has been developed in detail over a long period of time by many authors, including the author of this paper. The main shortcoming of all those explanations is the inability to explain the shape of the dye monomer bands from which J-aggregates are formed. In this mini-review, the author gives an explanation of the J-band as the so-called Egorov nano-resonance discovered in a new theory, quantum-classical mechanics, which includes an explanation of the shape of monomer bands. [ABSTRACT FROM AUTHOR]

Many researchers have investigated student reasoning in Newtonian mechanics. In 1979 Viennot revealed that most students associate the concept of force with the velocity or acceleration of a motion. Forty years later, student understandings remain a major challenge for teachers. The implications of this challenge are still unclear, however, including the effect on the instructions given by teachers. This paper investigated the perceptions that French teachers of science, technology and engineering have of core student misconceptions about, and learning difficulties with, the subject of force, and the extent to which these are dependent on a teacher's subject knowledge, and how they affect grade levels. One hundred teachers in the Académie d'Aix-Marseille, an educational organisation in the southeast France, were questioned randomly about their views on student learning issues of force. Teacher views were collected using an exploratory study based on an online questionnaire which included Likert-based and closed questions. The data was analysed using nonparametric tests. The analysis revealed four major outcomes: (1) main perceptions of misconceptions related to student 'impetus force' and 'force linked to an object weight', (2) key learning difficulties included 'knowledge transfer' and 'knowledge construction', (3) teachers believed that the Aristotelian view was still a common barrier to learning Newtonian mechanics, and (4) differences in perceptions were due, essentially, to the teachers' subject domain and not to the grades they taught. The only statistically significant difference in perceptions between teachers was linked to the idea of impetus force, with this corresponding to discipline philosophy. This paper provides baseline evidence about teacher perceptions of student learning about force, which suggests that more systemic teaching approaches are crucial to foster student conceptual understanding, transfer and knowledge construction. Some implications for teachers and curriculum developers are discussed. [ABSTRACT FROM AUTHOR]

In this paper is presented a pilot study for the investigation of the relevant factors within some experimental works carried out by students, after going through the learning unit "Movement and rest", which can be found in the chapter "Principles and laws in classical mechanics", from the physics curriculum for the ninth grade in Romania. Through the proposed work tasks, the design and the development of the experimental works carried out by students were highlighted. At the same time, special attention was paid to the results obtained by the students in investigating the relevant factors through specific physics methods, not only during the classes but also within the homework. [ABSTRACT FROM AUTHOR]

The time dependence of one-dimensional quantum mechanical probability densities is presented when the potential in which a particle moves is suddenly changed, called a quench. Quantum quenches are mainly addressed, but a comparison with results for the dynamics in the framework of classical statistical mechanics is useful. Analytical results are presented when the initial and final potentials are harmonic oscillators. When the final potential vanishes, the problem reduces to the broadening of wave packets. A simple introduction to the concept of the Wigner function is presented, which allows a better understanding of the dynamics of general wave packets. It is pointed out how special the broadening of Gaussian wave packets is, the only example usually presented in quantum mechanics textbooks. Quantum quenches occur when the Hamiltonian of a system is suddenly changed, so that the system is driven out of equilibrium. This paper, appropriate for graduate-level quantum mechanics classes, examines the similarities and differences of quantum quenches compared to their classical counterparts for three one-dimensional examples: the harmonic oscillator, the linear potential, and the zero potential for which the broadening of a non-Gaussian wave packet is addressed. [ABSTRACT FROM AUTHOR]

Georgiy (George) Albertovich Krasinsky was one of the scientists who made Soviet and later Russian science both advanced and competitive by arousing interest in it with the leading researchers around the world. Having received his education in the Department of Mathematics and Mechanics at Leningrad State University, for a long time he was engaged in research in the field of classical celestial mechanics, where he performed a number of first-class studies whose results are still in demand at present. The onset of the Space Age, with its sharp jump in the accuracy of astronomical observations, caused by the rapid development of technology, made Krasinsky realize that the classical methods of celestial mechanics and astrometry could no longer cope with the processing of up-to-date measurements, as these were unable to provide the accuracy of the ephemerides of the Solar System bodies at a level demanded by the new requirements. As a result, under his expert guidance and with his active participation, the ERA (Ephemeris Research in Astronomy) software system was developed, which became the basis for all of the later work at the Institute of Applied Astronomy of the Russian Academy of Sciences (IAA RAS) on processing modern high-precision measurements and formulating relativistic numerical theories of the orbital motion of the Solar System bodies. While working at the IAA RAS, George got deeply involved in such issues as the fundamental coordinate-time system, thus becoming one of those who were active in building up the quasar radio-interferometric network. During the last years of his life, George developed a numerical theory of the rotation of a deformable Earth with a liquid core, and theories of the evolution of both the rotational motion of the Earth and of the Moon's orbit. [ABSTRACT FROM AUTHOR]

In this paper, we investigate stability and optimization of an axially loaded nonlocal beam that is simply supported at one end and elastically restrained against rotation on the other. Nonlocal continuum mechanics is a theoretical framework that extends classical continuum mechanics to account for the influence of small length scales, especially in nanostructures. We analyze elastically buckling nanobeam based on Eringen's nonlocal elasticity theory. The Euler method of adjacent equilibrium configuration is used to derive the nonlinear governing equations. The critical axial force and postbuckling shape are obtained for the beam with the unit cross-sectional area. The shape of the nonlocal beam stable against buckling that has minimal volume is determined by using Pontryagin's maximum principle. The optimality conditions are derived. The cross-sectional area for optimally designed beam is found from the solution of a nonlinear boundary value problem. New numerical results are obtained. The first integral (Hamiltonian) is used to monitor the accuracy of the integration. The numerical analysis includes the influence of the characteristic parameter of the small length scale on the critical load, the postbuckling shape and the optimal shape of the analyzed beams. It is shown that there are the saving materials for optimally designed nanobeam in all numerical examples. [ABSTRACT FROM AUTHOR]

In the present paper we study the nonlinear system ut + [ϕ(u)]x + v = 0, vt + ψ(u)vx = 0 as a model for the one-dimensional dynamics of dark matter. We prove that under certain conditions this system, such as the Gurevich-Zybin system, can also explain why the observed rotation speed (relative to the galactic center) of stars near galactic halos do not coincide with what it is expected in classical mechanics. The solutions are obtained in fully explicit formulas, in a convenient space of distributions, without using any result within the classical framework. For such purpose we use the α-solution concept which is defined within a product of distributions. Such a concept generalizes the classical solution concept and for evolution equations may also be seen as an extension of the weak solution concept to the nonlinear setting. [ABSTRACT FROM AUTHOR]

• The compressive buckling analysis of cracked nanosheets is performed by XFEM, considering small-scale effect. • The contribution of this work is the study of buckling of nanosheets in the presence of a crack. • The studied variables include small-scaling parameter, crack length, nanosheet dimensions, and boundary supports. • The results show that the cracking phenomenon and the increase of its length intensify the nonlocal effect. The process used to produce nanosheets may cause damage such as cracks in them. These cracks can adversely affect the buckling capacity of nanosheets. The main contribution of this research endeavor is to extend the previous studies on undamaged nanosheets to the cracked ones concerning the size-dependent effect. On the nanoscale, the assumption of material continuity, which is the fundamental assumption in classical continuum mechanics, is not valid. In this case, nonlocal non-classical theories are employed to analyze nanosheets. The present paper examines the nonlocal buckling of cracked graphene sheets under uniaxial and biaxial loads. To this end, the governing equations are developed based on the first-order shear deformation theory and using Eringen's nonlocal elasticity theory. Moreover, cracked nanosheets with various boundary conditions are analyzed via the extended finite element method. The variables under study are the small scaling parameter, crack length, nanosheet dimensional parameters, and support conditions. The results indicate that while the small scaling parameter reduces the critical buckling capacity of nanosheets, the presence of a crack in the nanosheet and the increase in its length intensify the nonlocal effect. In addition, as the aspect ratio of the nanosheet increases from one, the nonlocal effect decreases gradually. The small-scale effect increases by constraining the edges of the cracked nanosheets. [ABSTRACT FROM AUTHOR]

The paper presents the numerical calculation of the group resistance to the incident particle impact on the supramolecular structure comprising rotating carbon nanotori. Methods of classical molecular mechanics are used to study the interaction between the particle and toroidal cluster in a columnar phase. The analysis is given to the influence of the nanotorus rotation frequency and the supramolecular structure dimensions on its resilience. [ABSTRACT FROM AUTHOR]

In this paper, we shall discuss the theory of geodesics in information geometry, and an application in astrophysics. We will study how gradient flows in information geometry describe geodesics, explore the related mechanics by introducing a constraint, and apply our theory to Gaussian model and black hole thermodynamics. Thus, we demonstrate how deformation of gradient flows leads to more general Randers–Finsler metrics, describe Hamiltonian mechanics that derive from a constraint, and prove duality via canonical transformation. We also verified our theories for a deformation of the Gaussian model, and described dynamical evolution of flat metrics for Kerr and Reissner–Nordström black holes. [ABSTRACT FROM AUTHOR]