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1
Pierrot, F., C. Reynaud und A. Fournier. „DELTA: a simple and efficient parallel robot“. Robotica 8, Nr. 2 (April 1990): 105–9. http://dx.doi.org/10.1017/s0263574700007669.
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SummaryThe DELTA parallel robot, designed by an EPFL (Ecole Polytechnique Fédérale de Lausanne) research team, is a mechanical structure which has the advantage of parallel robots and ease of serial robots modeling. This paper presents solutions for a complete modeling of the DELTA parallel robot (direct and inverse kinematics, inverse statics, inverse dynamics), with few arithmetic and trigonometric operations. Our method is based on a satisfactory choice of kinematic parameters and on a few restricting hypotheses for the static and dynamic models. We give some details of each model, we present some computation results and we put the emphasis on some particular points, showing the capabilities of this mechanical structure.
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Awrejcewicz, J., V. A. Krysko und I. V. Kravtsova. „Dynamics and statics of flexible axially symmetric shallow shells“. Mathematical Problems in Engineering 2006 (2006): 1–25. http://dx.doi.org/10.1155/mpe/2006/35672.
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In this work, we propose the method for the investigation of stochastic vibrations of deterministic mechanical systems represented by axially symmetric spherical shells. These structure members are widely used as sensitive elements of pressure measuring devices in various branches of measuring and control industry, machine design, and so forth. The proposed method can be easily extended for the investigation of shallow spherical shells, goffer-type membranes, and so on. The so-called charts of control parameters for a shell subjected to a transversal uniformly distributed and local harmonic loading force and resistance moment are constructed. The scenarios of the transition of vibration of shallow-type system into chaotic state are investigated with the use of the theory of differential equations and the theory of nonlinear dynamics. The method of the control of chaotic vibrations of flexible spherical shells subjected to a transversal harmonic load through a synchronized action of either harmonic resistance moment or force is proposed, illustrated, and discussed.
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Arnold, Lutz G., und Wolfgang Kornprobst. „COMPARATIVE STATICS AND DYNAMICS OF THE ROMER R&D GROWTH MODEL WITH QUALITY UPGRADING“. Macroeconomic Dynamics 12, Nr. 5 (November 2008): 702–16. http://dx.doi.org/10.1017/s1365100508070375.
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This paper replaces increasing product variety with quality upgrading in the Romer model [Romer, Paul M., Journal of Political Economy 98 (1990), S71–S102]. We show that the range of parameters for which a steady state exists can be divided into two subspaces with well-behaved comparative statics and saddle-point dynamics in one subspace, but with “perverse” comparative-statics properties and either equilibrium indeterminacy or instability in the other subspace. These results for the closed economy can also be used to characterize the dynamics of the M-country open-economy version of the model.
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Voronin, Anatolii, und Olga Gunko. „METHODS OF COMPARATIVE STATICS AND DYNAMICS IN THE THEORY OF ECONOMIC CYCLES“. Innovative Technologies and Scientific Solutions for Industries, Nr. 2 (16) (06.07.2021): 46–53. http://dx.doi.org/10.30837/itssi.2021.16.046.
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The subject of this work is the problem of describing the dynamic behavior of the price in the market of one product. The typical balance of interaction of supply and demand functions depending on the price is considered. The dynamic model of price evolution is based on the assumption that the demand function at a given time depends on the supply function at all previous points in time, i.e. there is a process with an aftereffect. The core of the integral transformation is a characteristic of the second order, which can initiate periodic regimes in price variables. The aim of the work is to synthesize a mathematical model of price changes in the market of one product and study the stability of its equilibrium states with the manifestation of the structure of marginal cycles. The task of the study is to demonstrate the degree of connection between the problem of stability of equilibrium and the problem of obtaining fruitful results in comparative statics. This duality is the principle of conformity of P. Samuelson. The basic mathematical model of the studied process of price dynamics is a system of two nonlinear differential equations of the first order. The research methods are the nonlinear theory of analysis of dynamical systems, the mathematical theory of stability of systems of differential equations, the conceptual apparatus of analysis of typical bifurcations of birth (death) of the boundary cycle, known as the Andronov-Hopf bifurcation. As a result of a detailed analysis of the properties and parameters of self-oscillating modes, a double cycle is revealed, i.e. there is a fact of coexistence around the equilibrium state of stable and unstable limit cycles. Subsequent mathematical transformations prove that the line of demarcation of these two cycles is completely determined by the static parameters of the studied system, which illustrates the mechanism of action of the principle of conformity of P. Samuelson. Conclusions: on the example of the functioning of the labor market, a comprehensive analysis of the stability of two positive equilibrium states, which characterize the effects of substitution and income. Computer simulations are used to perform computational experiments that demonstrate self-oscillating modes of price changes. As a result of the analysis of the obtained numerical results, it is possible to draw a conclusion about the stability of the limit cycle in the vicinity of the equilibrium state, which corresponds to the substitution effect.
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Zhu, Qidan, Peng Lu, Zhibo Yang, Xun Ji und Yu Han. „Multi-Parameter Optimization for the Wet Steam Accumulator of a Steam-Powered Catapult“. Energies 12, Nr. 2 (13.01.2019): 234. http://dx.doi.org/10.3390/en12020234.
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Selecting the optimal parameters for wet steam accumulator of steam-powered catapult is an important task, due to launching safety. There is no literature on the topic of the parameters optimization for wet steam accumulator of steam-powered catapult. The genetic algorithm (GA) was used to determine the optimal wet steam accumulator in this article. The sink-off-the-bow (SOB), angle of attack and rate of climb were used to create the objective function. The multi-objective optimization can be converted to single-objective optimization, which is subject to angle of attack and rate of climb. Moreover, the simulation model of the steam catapult system was built by creating a thermodynamics model of steam-powered catapult, a mathematical model of traction release device, a statics model of tensioning, a statics model of full takeoff power, a mathematical model of catapult force build-up with holdback, a model of release, a dynamics model of power stroke, a dynamics model of free deck run and a dynamics model of fly away. Finally, the optimal combination of the wet steam accumulator was obtained via numerical simulation. The GA method can effectively find the optimal parameters of wet steam accumulator, and its optimized parameters can increase the safety of catapult launch process.
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Sun, Jian Gang, Tie Jun Li, Xue Sen Zhang und Mei Ying Chen. „The Research on the Dynamics of High-Speed Friction and Wear Test System in Mechanical Engineering“. Advanced Materials Research 644 (Januar 2013): 326–32. http://dx.doi.org/10.4028/www.scientific.net/amr.644.326.
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By researching the dynamics of high speed friction and wear test system, establish the statics and dynamics model of high-speed dial and get the equation of motion of turntable scrapers state. Using Ansys Workbench software platform analysis the order modal of the turntable, get the kinetic parameters of the system. Some suggestion and methods are proposed on avoiding vibration of turntable system.
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Nassar, H., Y. Y. Chen und G. L. Huang. „A degenerate polar lattice for cloaking in full two-dimensional elastodynamics and statics“. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 474, Nr. 2219 (November 2018): 20180523. http://dx.doi.org/10.1098/rspa.2018.0523.
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A lattice design of a cloak for full two-dimensional elasticity is suggested when the background continuum is isotropic with Lamé parameters (λ, μ ) satisfying μ ≤ λ. The lattice is polar in the sense that it elastically resists rotations; and is degenerate meaning it admits a stressless collapse mechanism. These characteristics are attained through the use of appropriately distributed restoring torques in conjunction with hinge-like spring-mass contacts. Thus, the lattice is proven to exhibit a rank-3 elasticity tensor lacking the minor symmetries. Accordingly, it rigorously adheres to the form-invariance requirements of the transformation method under the Brun–Guenneau–Movchan gauge. The cloak is numerically tested in statics and in dynamics under pressure and shear incident waves and shows satisfactory performance. Finally, a theoretical generalization extends the design to three dimensions and to arbitrarily anisotropic backgrounds so as to enable cloaking as well as other transformation-based static and dynamic field manipulation techniques in these cases.
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Zhou, Zhi, Xing Man Yang, Zhi Ming Zhao und Gang Chen. „Strength Analysis of Towing Extending-Retracting Equipment Based on Dynamics and Statics“. Advanced Materials Research 902 (Februar 2014): 173–78. http://dx.doi.org/10.4028/www.scientific.net/amr.902.173.
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With the increasing development of ocean engineering, towing extending-retracting equipment used widely is the basic platform realizing the engineer value of towfish. In this paper, the dynamic model of the equipment in rough sea condition is created based on Adams, and the operating parameters are determined by maximum dynamic load, as the input data of static model of the equipment. Then the static models of capture unit, swing arm and base frame are created to calculate the strength respectively. Lastly, from the results, the valuable suggestions are put forward to provide valuable references for optimization design and engineer application in future.
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Li, Ying Ge, Dian Cai Geng, Fa Hu Zhang und Dong Xing Du. „Proper Index of Foam Statics Characteristics on Predicting Foam Dynamics Behavior in Porous Media“. Key Engineering Materials 561 (Juli 2013): 411–16. http://dx.doi.org/10.4028/www.scientific.net/kem.561.411.
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Proper foam statics index can give essential indications on foam dynamic behavior in porous media. In this paper, the statics characteristics are investigated through air-flow method for foam generated with Sodium Dodecyl Sulfate (SDS) surfactant. Parameters of foam height, foam half period time are recorded for various gas phases, surfactant concentrations and injecting gas flow rate, and foam morphology are also visually monitored. It is found the N2 generated foam has better characteristics on foam height, while poorer characteristics on foam half-time period compared to air and CO2 foam. Widely employed Foam Composite Index (FCI) is no longer suitable for predicting foam dynamic behavior, a Foam Index for predicting Dynamic Behavior in Porous Media (FIDBPM) is therefore defined to predict properly the foam transient propagation process in porous media.
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AKSENOVA, KSENIYA A., DMITRIY A. BELYAEV und SERGEY A. KUTOMANOV. „REGULAR MECHANISMS FOR THE METAPHORIZATION OF QUANTITATIVE MEANINGS IN ITALIAN AND FRENCH: COMPARATIVE ANALYTICS“. Cherepovets State University Bulletin 4, Nr. 103 (2021): 7–17. http://dx.doi.org/10.23859/1994-0637-2021-4-103-1.
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The paper aims at identifying metaphorization of quantitative lexemes as a basic means to form quantifiers. The research objective is to develop a classification of qualitative parameters for the Italian and French quantifiers. In particular, a structural approach is used, based on such methods of material analysis as the comparative-typological method, contextual analysis, and the method of lexicographic definitions. The authors pay attention to the identification of qualitative parameters, a set of properties that characterizes the quantifiers under study. All identified parameters are analysed in a comparative manner. The authors have pointed to such parameters as deicticity, statics / dynamics, connotation, homogeneity / heterogeneity, simultaneity / sequence.
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Gurova, O. Yu, A. E. Bobrov, T. I. Romantsova und O. V. Roik. „Metabolic abnormalities and behavioral peculiarities in patients with obesity: statics and dynamics on Orlistat therapy“. Obesity and metabolism 6, Nr. 3 (15.09.2009): 27–38. http://dx.doi.org/10.14341/2071-8713-5242.
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Obesity causes variety of metabolic disorders, and decreases the quality of life. At the same time many people with BMI>30 kg/A possess different psychopathologic disturbances. The results of ourwork disclose high percentage of impaired carbohydrate metabolism, hyperlipidemia, and resistance to insulin in patients with obesity Besides, it was revealed that more than a half of the patients have symptoms of maladjustment, and decreased quality of life. Reduction of body w eight due to the treatment with Orlistat w as accompanied by improvement in parameters of carbohydrate and lipid metabolism and quality of life
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Lin, Sheng, Jian Xu und Chun Wang. „Synthesis and experiment of a novel parallel compliant mechanism with one translation and two rotations“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, Nr. 12 (15.02.2016): 2284–90. http://dx.doi.org/10.1177/0954406216630336.
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A novel parallel compliant mechanism with one translation and two rotations is proposed. Its stiffness matrix and force/torque performance indices are derived. The influence of temperature on the output displacement of the compliant mechanism is deduced. Structure parameters of the compliant are optimized with the force and torque performance indices as objective and the equivalent nodal thermal load as constraint condition. The statics and dynamics experiments are conducted to verify the compliant mechanism rationality.
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Mathe, Aliz, Al Cătărig und Ilinca Moldovan. „Statics And Kinematics Of Semirigid Steel Frames Under Seismic Action“. Journal of Applied Engineering Sciences 5, Nr. 2 (01.12.2015): 59–64. http://dx.doi.org/10.1515/jaes-2015-0022.
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Abstract Intended contribution emphasizes the statics and kinematics of semi-rigid steel frames seismically acted upon. The dynamic model of analyzed structures consists of multi degree of freedom systems with lumped masses located at floor levels. The dynamic degrees of freedom are the lateral seismically induced floor displacements. A cyclic behavior of semi-rigid beam – column connections associated with the four parameters analytical bending moment M – relative rotation θr is considered. Time history seismic analyses are performed on multi-story steel planar frames equipped with several top and seat and web angle beam – column connections acted upon by recorded seismic actions. The computed numerical results refer to the contrary static and effects of semi-rigidity: the increase in lateral floor displacements accompanied by a decrease in the seismic base shear force. Relevant comments are drawn.
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Chen, Shi Wei, und Kai Lin Jian. „Robust Optimization of Dynamic Response of Structures with Uncertain Parameters“. Applied Mechanics and Materials 105-107 (September 2011): 527–31. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.527.
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On the base of traditional robust optimal design in statics, in this paper, by considering the system under the incentive force of the arbitrary time function, the dynamic response robust optimal design problem, when system dynamic response can only be calculated using numerical integration. Considering the environmental interference factors in a system, derived the expression of response with a small parameter perturbation finite element method. Through the tiny fluctuation frame system in a post and beam’s elastic modulus, realize the robust optimal design of the structural dynamic response, and using New-mark method for dynamic analysis, robust optimal design is applied in dynamic response optimization. Compared to the traditional optimal design’s result in a frame system, robust optimal design of the frame displayed a significant improvement in performance.
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FALZARANO, JEFFREY M., STEVEN W. SHAW und ARMIN W. TROESCH. „APPLICATION OF GLOBAL METHODS FOR ANALYZING DYNAMICAL SYSTEMS TO SHIP ROLLING MOTION AND CAPSIZING“. International Journal of Bifurcation and Chaos 02, Nr. 01 (März 1992): 101–15. http://dx.doi.org/10.1142/s0218127492000100.
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Ship capsizing is a highly nonlinear dynamic phenomenon where global system behavior is dominant. However the industry standards for analysis are limited to linear dynamics or nonlinear statics. Until recently, most nonlinear dynamic analysis relied upon perturbation methods which are severely restricted both with respect to the relative size of the nonlinearity and the region of consideration in the phase space (i.e., they are usually restricted to a small local region about a single equilibrium), or on numerical studies of idealized system models. In this work, recently developed global analysis techniques (e.g., those found in Guckenheimer and Holmes [1986], and Wiggins [1988, 1990]) are used to study transient rolling motions of a small ship which is subjected to a periodic wave excitation. This analysis is based on determining criteria which can predict the qualitative nature of the invariant manifolds which represent the boundary between safe and unsafe initial conditions, and how these depend on system parameters for a specific ship model. Of particular interest is the transition which this boundary makes from regular to fractal, implying a loss in predictability of the ship’s eventual state. In this paper, actual ship data is used in the development of the model and the effects of various ship and wave parameters on this transition are investigated. Finally, lobe dynamics are used to demonstrate how unpredictable capsizing can occur.
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Zeng, Fan, Jing Jun Lou und Shi Jian Zhu. „Study on Giant Magnetostrictive Material with Design and Simulation of Displacement Magnifying Mechanism“. Advanced Materials Research 675 (März 2013): 219–26. http://dx.doi.org/10.4028/www.scientific.net/amr.675.219.
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In order to make full use of advantages of giant magnetostrictive material and to improve output characteristics of giant magnetostrictive actuator, displacement magnifying mechanism is designed based on flexible hinges. The design parameter of the flexible hinges and strength of material of flexible hinges are calculated. Based on the analysis and comparison, the statics and dynamics analysis was carried on by analytic method and ANSYS12.1 software,the input stiffness, magnifying multiple and the relationship between output displacement and load are calculated,and the stress analysis shows that the maximum stress of magnifying mechanism is less than the maximum allowable stress of materials. The resonance frequency,vibration modes and harmonic response of the mechanism were resulted by Finite element method, and the dynamics parameters of system are get.
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Han, Jianxin, Lei Li, Gang Jin, Wenkui Ma, Jingjing Feng, Haili Jia und Dongmei Chang. „Qualitative Identification of the Static Pull-In and Fundamental Frequency of One-Electrode MEMS Resonators“. Micromachines 9, Nr. 12 (22.11.2018): 614. http://dx.doi.org/10.3390/mi9120614.
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This paper attempts to qualitatively identify the static pull-in position, pull-in voltage, and fundamental frequency of one-electrode microresonators from a physical perspective. During theoretical derivation, a generalized one-degree-of-freedom (1-DOF) model in nondimensional form derived using the differential quadrature method (DQM) is first introduced and then transformed for frequency normalization. Based on the deduced formulas, the upper and lower bounds of the static pull-in position and pull-in voltage are both deduced through mathematical proof. To distinguish the monotonic and nonmonotonic behavior of the fundamental frequency versus direct current (DC) voltage, a critical condition decided only by cubic stiffness is then determined. For the first time, two extreme static positions, as well as the corresponding fundamental frequencies and DC voltages to identify different frequency behaviors are derived, and their variations versus cubic stiffness are then discussed and verified. During the simulation process, a high-order DQM and COMSOL 2D model are both applied for numerical analyses. Guided by nondimensional results, typical behaviors with specific physical parameters are examined in detail. Results demonstrate that the curve tendencies between all the qualitative results and quantitative numerical simulations in dimensional form agree well with each other, implying the possibility of using 1-DOF model to qualitatively discuss physical parameters effects on the system statics and dynamics.
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Yang, Fu Qin, Hong Tao Zhang, Rong Zong und De Gong Chang. „Parametric and Optimum Design of Cylinder Mechanism Based on Statics and Modal Analysis“. Applied Mechanics and Materials 215-216 (November 2012): 311–14. http://dx.doi.org/10.4028/www.scientific.net/amm.215-216.311.
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Collaborative simulation on characteristic parameters of the cylinder mechanism was realized by Pro/E and AWE software. Optimum allocation about the structure parameters like wall thickness, width, diameter and speed was completed based on comprehensive consideration of static strength and stiffness and dynamic characteristics of modal. The simulation result shows that the optimization scheme was beneficial to the yield and quality of cardings which lays the foundation for further development of the cylinder mechanism.
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Kodnyanko, Vladimir, Stanislav Shatokhin, Andrey Kurzakov und Yuri Pikalov. „Mathematical Modeling on Statics and Dynamics of Aerostatic Thrust Bearing with External Combined Throttling and Elastic Orifice Fluid Flow Regulation“. Lubricants 8, Nr. 5 (19.05.2020): 57. http://dx.doi.org/10.3390/lubricants8050057.
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As aerostatic bearings are used in high-speed metal-cutting machines to increase machining accuracy, there is the need to improve their characteristics, including compliance, which is usually high. In practical applications, a significant reduction of bearing compliance is often necessary, sometimes down to zero and even negative values, to ensure automatic compensation of the elastic deformation in the machine technological system. A decrease in compliance leads to deterioration in the dynamic performance of the bearing, so it is necessary to develop new designs that meet the above requirements. This article considers an aerostatic bearing, in which decrease in compliance is ensured by the use of air throttling with elastic orifices. To ensure its stability, the principle of combined external throttling was applied, which can substantially improve the dynamics of conventional aerostatic bearings. A mathematical model of the elastic orifice deformation was developed, together with the flow rate performance calculation method. The method ensured full qualitative and satisfactory quantitative agreement with the experimental data. The model was used in the mathematical modeling of the aerostatic bearing movement. The article also proposes a method to calculate the static load capacity and compliance of a bearing, as well as a numerical method for fast computation of its dynamic performance, which allows for real-time multi-parameter optimization by the bearing dynamic performance criteria. The study showed that there is an optimal set of design parameters for which low, zero, and negative static compliance of the bearing is ensured, with the necessary stability margin, high speed, and the non-oscillatory nature of the transient processes.
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Roorda, J., und B. Gracie. „Derailment of Trains“. International Journal of Mechanical Engineering Education 22, Nr. 3 (Juli 1994): 165–76. http://dx.doi.org/10.1177/030641909402200302.
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A simple model of train derailments reduces a complex dynamic process to a recursive series of statics and geometry calculations accompanied by computation of energy dissipation by ground friction forces. A calibration of the model parameters ensures a good fit to reality. Some derailment characteristics can be predicted.
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Zhao, Long, Yifei Yan, Xiangzhen Yan und Lei Zhao. „Structural Parameters Optimization of Elastic Cell in a Near-Bit Drilling Engineering Parameters Measurement Sub“. Sensors 19, Nr. 15 (30.07.2019): 3343. http://dx.doi.org/10.3390/s19153343.
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The downhole engineering parameters measurement sub is a key component of the rotary steerable drilling system. To enable a measurement sub to serve reliably under downhole complex conditions, the structural parameters optimization of its key but weak elastic cell is systematically studied. First, the multiple relations among measurement sensitivities, structural stiffnesses, and strength during structural parameters design are summarized. Second, the selection of the structural parameters of the elastic cell is characterized as a multi-objective optimization model, which is solved using the non-dominated sorting genetic algorithm II (NSGA-II). Furthermore, the finite element method (FEM) is used to verify the measurement performance and static strength of the proposed structure. Finally, transient dynamics analysis is applied to investigate the dynamic strength of the designed structure. The results show that the proposed parameters optimization strategy can quickly obtain the database for the structural parameters design of an elastic cell. The static analysis results based on the FEM further verify the effectiveness of the proposed method. Transient dynamic analysis also reveals the relative rigor of the proposed methodology framework to some extent. This work has practical significance for improving the drilling efficiency and reducing drilling risks. In addition, this proposed methodology has good extensibility.
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Kaletnіk, Grigory, und Oleh Tsurkan. „STATIC CONDITIONS OF A LOOSE ENVIRONMENT IN SOLVING THE TASKS OF ITS VIBROMOVEMENT“. Vibrations in engineering and technology, Nr. 4(95) (20.12.2019): 5–15. http://dx.doi.org/10.37128/2306-8744-2019-4-1.
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The method of formalizing a granular medium in the form of a continuous deformable medium provides that the granular medium is continuous. In this case, the methods of mechanics of continuous deformable media in Eulerian or Lagrangian coordinates are used. The method allows you to take into account the interaction between particles in the form of elastic, viscous or plastic components of internal resistance. With this formalization, the most widespread application of the Navier-Stokes equation. Unfortunately, the exact correct solution of such an equation in an analytical form does not exist. It should be noted that the most common method is formalization in the form of a loose discrete medium. It can be used under conditions when the dimensions of the element, in which the changes in the kinematic and dynamic parameters are determined, exceed by at least an order of magnitude the maximum size of a fraction of a granular medium. With this formalization, you can use the methods of mechanics of granular discrete media. When solving the problems of dynamics of motion of a loose discrete medium, it becomes necessary to compose the equations of its statics, which are necessary to solve the problems of dynamics. This is because the static equations allow one to supplement the boundary conditions and provide nonzero solutions for the problems of oscillations of a loose discrete medium, since during oscillations of such a medium zero values of quantities determined (density and velocity components of displacements) can occur at points where their functions intersect the zero line relative to which oscillating motion occurs. The article describes the conditions of the static state of a granular medium in a working chamber, which are an addition to the boundary conditions when solving the problems of oscillations of a granular discrete medium, which is formalized as continuous with a significant manifestation of dry friction.
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Kao, B. G., und T. Warholic. „BAT Model Lateral Parameters Characterization Using Finite Element Model“. Tire Science and Technology 31, Nr. 4 (01.10.2003): 225–47. http://dx.doi.org/10.2346/1.2135270.
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Abstract The bushing analogy tire (BAT) model has been shown to be capable of modeling tire dynamics in vehicle dynamic simulations. In a recent paper, the tire and vehicle data have been used to demonstrate that the BAT model yields reasonable predictions of the vehicle vertical suspension dynamic responses up to the tire 2nd vertical mode (∼90 Hz). This paper studies the modeling of the tire dynamics in the lateral direction as the next step toward completion of the BAT model as a consistent 3-dimensional tire dynamics model. Finite element (FE) analysis is an advanced analytical method for engineering analysis and has been accepted as the standard analytical tool for tires in the automotive industry. The tire data generated with FE models are also repeatable, without the data noise contained in physically measured laboratory tire data. FE models are also ideal for tire modeling studies because they enable the analysts to precisely control the modeling parameters. A tire FE model is, therefore, used here to generate the needed tire data, including mass, static forces and dynamic vibration modes for BAT model characterization. The BAT model parameters, including the tire lateral stiffnesses and the tire/wheel mass and inertia, are extracted from the FE analysis results. The analytically predicted lateral vibration modal frequencies of the BAT model are then compared with the corresponding lateral vibration modes of the same FE model. It is shown that the resulting BAT model is a good approximation for the FE model in the lateral direction up to the third lateral (including rotational) vibration mode (∼70 Hz).
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Wu, Bo, Xiao Dong Yu, Xue Mei Chang und Chao Yin. „Influence of Working Parameters on Dynamic Pressure Effect of Heavy Constant Flow Hydrostatic Center Rest“. Applied Mechanics and Materials 274 (Januar 2013): 82–86. http://dx.doi.org/10.4028/www.scientific.net/amm.274.82.
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In order to increase the working performance of a heavy constant flow hydrostatic center rest, a theoretical study concerning the lubricating oil film dynamic pressure effect of the heavy constant flow hydrostatic center rest is described. The Computational Fluid Dynamics and the Finite Volume Method have been used to compute numerically the static pressure field and the total pressure field of the lubricating oil film. The influences of spindle rotating rate, lubricating oil dynamic viscosity and inlet flow rate on the lubricating oil film dynamic pressure effect of the heavy constant flow hydrostatic center rest were analyzed based on the computational fluid dynamics and lubrication theory, and the influencing laws were revealed. By means of this method, the reasonable data can be provided for reasonably controlling dynamic pressure and structure optimal design of the heavy constant flow hydrostatic center rest.
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Шавьолкін, О. О., І. О. Шведчикова, Г. В. Кругляк, Р. М. Марченко und А. В. Пісоцький. „РОЗРОБЛЕННЯ ЕКСПЕРИМЕНТАЛЬНОЇ УСТАНОВКИ ДЛЯ ВИПРОБУВАНЬ ПРОГРАМНО-АПАРАТНИХ ЗАСОБІВ УПРАВЛІННЯ МІКРОЕНЕРГЕТИЧНИМИ МЕРЕЖАМИ ЛОКАЛЬНИХ ОБ’ЄКТІВ“. Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 148, Nr. 4 (10.03.2021): 14–24. http://dx.doi.org/10.30857/1813-6796.2020.4.1.
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Development of the experimental installation for testing of the software and hardware tools of management of a photovoltaic system of a local facility connected to the grid, which, along with checking its operability, will allow analyzing the operation and adjusting the settings of systems with different parameters under different weather conditions, load schedules and operating modes. Method. Experimental research with preliminary justification of settings based on calculations and simulation data obtained in the Matlab software package. Results. The structure and experimental installation on the base of the photovoltaic system with storage battery and using a photovoltaic battery emulator with software control of generation and load power were developed. The software modules of the system have been developed. According to the results of the simulation, the moments of time are determined when the operating mode is switched in the experimental setup. The experimental setup was tested in static and dynamic modes. Static tests were aimed at checking the functioning of the photovoltaic battery emulator in accordance with the specified solar radiation power and the temperature of the photo module, as well as checking the correctness of the model used in the program. Tests in statics with fixed parameters and in dynamics in the daily cycle, in general, confirmed the efficiency of the proposed solutions. Scientific novelty. The method of experimental research in the daily cycle of photovoltaic systems control with the use of software-controlled emulators of a photovoltaic battery and load with power and time scaling was developed. This, along with the acceleration of the experiment, allows us to estimate the effectiveness of the tested systems at different ratios of system parameters and adjust the functioning algorithms. Practical importance. The proposed solutions for the implementation of the experimental installation allow minimizing material costs and time costs in the process of testing and development of software and hardware control tools of a photovoltaic system with storage battery.
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Šnīders, A. „Transient Process Modelling in Waste Water Aeration Unit“. Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 1 (26.06.2006): 269. http://dx.doi.org/10.17770/etr2003vol1.2017.
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To minimize the expenditure of electrical energy for communal waste water biological treatment the simulation and investigation of oxygen transfer efficiency in aeration tank have been made. Soluted oxygen transfer efficiency ? 0 (Fig.1.) is one of the main important factor directly estimating the expenditure of electrical power for waste water aeration. The research object is an aeration tank (Fig.2.) with one input impact -–the air blower’s capacity Lg (m3/h), one output controlled parameter – dissoved oxygen concentration C (g/m3) and several perturbances such as waste water temperature T (oC), waste water afflux Q (m3/h) and biological oxygen need La (g/m3) for complete purification. Oxygen’s transfer efficiency depends on the waste water temperature, the depth of aerator immersion h (m), air flow intensity ? d (m3/disc.h) and the air diffusor’s density ? s. For simulation and practical design of the air blower control system the equations of statics C=f(Lg, Q, La, T, h, ? d , ? s) and dynamics C=f(t) have been compiled. That made possible to estimate the static gains for control channel Ka and for perturbances Kq, KT as well as the time constant of the aeration tank Ta. The analysis prove that the aeration tank is a non-stationary control object with the variable static and dynamic parameters and needs adaptive controller with predication of oxygen consumption. The block diagram for transient process simulation of the oxygen concentration control system have been compiled using model of the actual PID controller and the “Matlab” subprogram “Simulink”.
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Ivanov, Vladimir. „Dynamic Compensation of Parameters in Servo Drives“. Известия высших учебных заведений. Электромеханика 64, Nr. 3 (2021): 36–44. http://dx.doi.org/10.17213/0136-3360-2021-3-36-44.
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In this paper, we studied a servo drive with an unlimited increase in the gain coefficients of the speed con-tour. We demonstrated dynamic compensation of parameters associated with the formation of differential com-ponents based on the coverage of the real coordinates of the control object using static model. It was shown that dynamics of the transient processes is caused by real differentiating links determining the fast and slow components of the transient process. The static velocity error in this case did not depend on the ratio of large and small time constants, as in a single integrating system of subordinate regulation of parameters. Therefore, we considered that parametric disturbances and their compensation occur due to the external astatic circuit. We demonstrated an equivalent transition to the position contour, the speed structure and position generator, corresponding to the organization of the servo drive in the CNC systems. We investigated features of the phase discriminator during the operation of the position sensor in the phase difference mode and carried out model-ing of the servo drive structures and comparative analysis of two and three-circuit systems.
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Chang, De Gong, S. M. Li und Cong Feng An. „The Influence Analysis of Globular Indexing Cam Mechanism Size Parameters on Transmission Performance“. Advanced Materials Research 426 (Januar 2012): 163–67. http://dx.doi.org/10.4028/www.scientific.net/amr.426.163.
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The globular indexing cam mechanism is a kind of high-speed and high-precision indexing mechanism, widely used in the field of mechanical transmission, which has the character of smooth transmission, high-precision indexing, large transfer torque, wider choice of dynamic and static ratio, simple structure and low cost, etc. In this paper, the working principle and the main movement parameters of globular indexing cam mechanism are analyzed, and the dynamics simulation of this mechanism is done by using ADAMS dynamic simulation software to analyze the influence of size parameters on the transmission performance, which provides reliable theoretical basis for understanding the property and designing the parameter of globular indexing mechanism.
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Dew, Ryan, Asim Ansari und Yang Li. „Modeling Dynamic Heterogeneity Using Gaussian Processes“. Journal of Marketing Research 57, Nr. 1 (14.10.2019): 55–77. http://dx.doi.org/10.1177/0022243719874047.
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Marketing research relies on individual-level estimates to understand the rich heterogeneity of consumers, firms, and products. While much of the literature focuses on capturing static cross-sectional heterogeneity, little research has been done on modeling dynamic heterogeneity, or the heterogeneous evolution of individual-level model parameters. In this work, the authors propose a novel framework for capturing the dynamics of heterogeneity, using individual-level, latent, Bayesian nonparametric Gaussian processes. Similar to standard heterogeneity specifications, this Gaussian process dynamic heterogeneity (GPDH) specification models individual-level parameters as flexible variations around population-level trends, allowing for sharing of statistical information both across individuals and within individuals over time. This hierarchical structure provides precise individual-level insights regarding parameter dynamics. The authors show that GPDH nests existing heterogeneity specifications and that not flexibly capturing individual-level dynamics may result in biased parameter estimates. Substantively, they apply GPDH to understand preference dynamics and to model the evolution of online reviews. Across both applications, they find robust evidence of dynamic heterogeneity and illustrate GPDH’s rich managerial insights, with implications for targeting, pricing, and market structure analysis.
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Barchiesi, Emilio, und Sergei Khakalo. „Variational asymptotic homogenization of beam-like square lattice structures“. Mathematics and Mechanics of Solids 24, Nr. 10 (28.04.2019): 3295–318. http://dx.doi.org/10.1177/1081286519843155.
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By means of variational asymptotic homogenization, using Piola’s meso-macro ansatz, we derive the linear Timoshenko beam as the macro-scale limit of a meso-scale beam-like periodic planar square lattice structure. By considering benchmarks in statics and dynamics, meso-to-macro convergence is numerically analyzed. At the finest micro-scale, a 2D assembly of elastic, geometrically linear, isotropic and homogeneous Cauchy continua in plane strain with different material parameters is considered. Using this description, we calibrate the meso-scale model using standard methodology and, by exploiting the meso-to-macro homogenization scaling laws, we recover bending and shear Timoshenko beam moduli. It turns out that the Timoshenko beam found in this way and the finest-scale description based on the Cauchy continuum are in excellent agreement.
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Vershok, I. L. „Interdisciplinary Approach to the Analysis of the Dynamics of Legal Consciousness“. Siberian Law Review 17, Nr. 4 (31.12.2020): 438–54. http://dx.doi.org/10.19073/2658-7602-2020-17-4-438-454.
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The article deals with the dynamic aspects of legal consciousness. It is concluded that the traditional definition of legal consciousness as a set of emotions, ideas and feelings about the current and previously valid law was formed on the basis of the dominant materialistic concept as the ideological basis of knowledge in jurisprudence. Its use as a universal method determined the study of certain aspects of legal consciousness as an object of research activity, existing in the form of a reflection of the surrounding (legal) reality. As a result, the definition of legal consciousness in statics was formed, due to the analysis of individual external (materialized) signs of its manifestation (exteriorization). The existing lack of data on the peculiarities of the internal processes of the dynamics of legal consciousness was compelled to compensate for the study of mental processes and their corresponding parameters only on the basis of introspection. The article clearly demonstrates that this approach leads to various kinds of distortions, entailing errors in solving the fundamental problems of defining the phenomenon of legal consciousness, as well as a decrease in the quality of the practice of lawmaking and law enforcement. In order to overcome the gap that has arisen in theoretical and applied research, it is proposed to consider legal consciousness as a subject of scientific knowledge by constructing an integral theoretical scheme of its dynamics (flow) as a complex socio-psychological process. For this, an interdisciplinary approach is applied to the study of the dynamics of legal consciousness, on the basis of which a number of practical data from psychology, sociology, and cybernetics are synthesized. The definition of legal consciousness is formed on the basis of the decomposition of the concept into separate stages of legal consciousness with an analysis of their functional parameters. The main stages of the course of legal consciousness are recognized as the perception of the subject of legal regulation and its mediating legal norms with the formation of separate perceptual images, then – the corresponding perceptual activity with a certain centralization and cognitive processes with a possible result in the form of constructing mental schemes. The key parameters of legal consciousness are the generic-specific connection with consciousness, the absence of discreteness, as well as the specific formally-legally determined intentional orientation, temporality, coherence and tension of legal consciousness due to the subject's readaptation. Moreover, the target orientation, coherence and tension are largely predetermined by the methods and content of legal impact. As examples illustrating the proposed scheme of dynamics of legal consciousness, the phenomena of the so-called deformation of legal consciousness, approaches to the definition of subjectivity and legal personality, structural and substantive aspects of legal capacity and legal capacity, parameters of the subjective side of the offense, problems of professional legal consciousness and a number of other applied issues.
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Vershok, I. L. „Interdisciplinary Approach to the Analysis of the Dynamics of Legal Consciousness“. Siberian Law Review 17, Nr. 4 (31.12.2020): 438–54. http://dx.doi.org/10.19073/2658-7602-2020-17-4-438-454.
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The article deals with the dynamic aspects of legal consciousness. It is concluded that the traditional definition of legal consciousness as a set of emotions, ideas and feelings about the current and previously valid law was formed on the basis of the dominant materialistic concept as the ideological basis of knowledge in jurisprudence. Its use as a universal method determined the study of certain aspects of legal consciousness as an object of research activity, existing in the form of a reflection of the surrounding (legal) reality. As a result, the definition of legal consciousness in statics was formed, due to the analysis of individual external (materialized) signs of its manifestation (exteriorization). The existing lack of data on the peculiarities of the internal processes of the dynamics of legal consciousness was compelled to compensate for the study of mental processes and their corresponding parameters only on the basis of introspection. The article clearly demonstrates that this approach leads to various kinds of distortions, entailing errors in solving the fundamental problems of defining the phenomenon of legal consciousness, as well as a decrease in the quality of the practice of lawmaking and law enforcement. In order to overcome the gap that has arisen in theoretical and applied research, it is proposed to consider legal consciousness as a subject of scientific knowledge by constructing an integral theoretical scheme of its dynamics (flow) as a complex socio-psychological process. For this, an interdisciplinary approach is applied to the study of the dynamics of legal consciousness, on the basis of which a number of practical data from psychology, sociology, and cybernetics are synthesized. The definition of legal consciousness is formed on the basis of the decomposition of the concept into separate stages of legal consciousness with an analysis of their functional parameters. The main stages of the course of legal consciousness are recognized as the perception of the subject of legal regulation and its mediating legal norms with the formation of separate perceptual images, then – the corresponding perceptual activity with a certain centralization and cognitive processes with a possible result in the form of constructing mental schemes. The key parameters of legal consciousness are the generic-specific connection with consciousness, the absence of discreteness, as well as the specific formally-legally determined intentional orientation, temporality, coherence and tension of legal consciousness due to the subject's readaptation. Moreover, the target orientation, coherence and tension are largely predetermined by the methods and content of legal impact. As examples illustrating the proposed scheme of dynamics of legal consciousness, the phenomena of the so-called deformation of legal consciousness, approaches to the definition of subjectivity and legal personality, structural and substantive aspects of legal capacity and legal capacity, parameters of the subjective side of the offense, problems of professional legal consciousness and a number of other applied issues.
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Ignatkin, V. „Features of Dynamic Error Analysis in the Process of Evaluation of Metrological Reliability of Measuring Equipment“. Metrology and instruments, Nr. 2 (03.05.2019): 36–42. http://dx.doi.org/10.33955/2307-2180(2)2019.36-42.
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The article discusses metrological reliability of measuring equipment (ME), argues that ME imprecision must be considered not in statics, 'out in dynamics, taking into account the change of its characteristics over time. Measurement imprecision and its components are considered as random processes that are fully characterized by multidimensional distribution. It is advisable to determine the probability of metrological measurements directly from the experiment due to the difficulties of analytical solution to the problem. The characteristics of dynamic imprecision depend on both the values of the measured object and the ME properties. The physical cause of dynamic imprecision taking place is inertia of ME, its exhaustive description relies on the use of Duamel integral, which determines the response of inertial link to the input influence. As a criterion for signal differences one can use quite different functionals, taking into account further use of measurement results, the convenience of computing, the properties or input influences, and so on. It is most expedient to use the dispersion of signal differences. To calculate the parameters of dynamic imprecision it is necessary to know the energy spectrum of the input signal. The given ratios can be used for both stationary and non-stationary processes.
The paper provides examples of using these ratios, recommendations for reducing measurement errors in each particular case.
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Берестин, D. Berestin, Попов, Yuriy Popov, Вохмина, Yu Vokhmina, Хадарцева und K. Khadartseva. „Possibilities of stochastic processing of system parameters with chaotic dynamics“. Complexity. Mind. Postnonclassic 3, Nr. 2 (21.05.2014): 59–67. http://dx.doi.org/10.12737/5519.
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The paper presents the first attempt to combine methods of stochastics (mathematical statistics) and methods of theory of chaos and self-organization for studying such complex (chaotic) processes as postural tremor. It was established that when re-registering tremor in each subject by n=15 or n=30 obtained tremorograms do not exhibit normal distribution, and non-parametric distributions show distinctions at pairwise comparison on Wilcoxon test (only 2 or 3 pairs from 210 may belong to the same general population). Static physical load sharply changes this picture and the number of such ("similar") pairs increases. The estimation method for effect of a load on tremor is proposed. Simultaneously, within calculating quasi-attractors there is a clear picture of division of chaotic dynamics of tremor parameters with load and without load. Prospects of a new method application in physiological measurements are discussed. Limited method of stochas- tics in description of complexity is underlined, and necessity of calculation quasi-attractor´s parameters in phase space of state is proved.
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Li, Huai Yong, Su Jing Wang, Ying Xun Guo und Jian Hua Huang. „Mechanical Analysis of the Arm Lifting Rope of the Dynamic Compaction Machine“. Applied Mechanics and Materials 851 (August 2016): 259–64. http://dx.doi.org/10.4028/www.scientific.net/amm.851.259.
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In this paper, the mechanics equation of the dynamic compaction machine arm frame is established based on the theory of statics, the arm lifting rope force is given, the influence of the wire rope force with relative position parameters changing is also discussed. The critical factors that affect the arm lifting rope force are identified. Compared the simulation and the test results, the major forces errors are less than 8%. The correctness of the theoretical study and simulation are verified. The research results could be used for the arm wire rope type selection of the dynamic compaction.
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Gómez, Manuel A. „EQUILIBRIUM DYNAMICS IN AN ENDOGENOUS GROWTH MODEL WITH HABIT FORMATION AND ELASTIC LABOR SUPPLY“. Macroeconomic Dynamics 19, Nr. 3 (11.11.2013): 618–42. http://dx.doi.org/10.1017/s1365100513000503.
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This paper analyzes the dynamics of an endogenous growth model with external habit formation and elastic labor supply. We first derive the conditions for the existence, uniqueness, and saddlepath stability of a feasible steady state with positive long-run growth. The global dynamics of the economy are characterized by phase-diagram analysis. Then we characterize the comparative static effects of shocks in preferences and production parameters analytically. The comparative dynamic effects of the shocks are characterized by phase-diagram analysis.
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Zhang, Yao Man, Ren Jun Gu und Guang Xiao Yang. „Static and Dynamic Characteristic Analysis for the HSR Series Linear Motion Guide“. Advanced Materials Research 834-836 (Oktober 2013): 1488–92. http://dx.doi.org/10.4028/www.scientific.net/amr.834-836.1488.
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The dynamic characteristic of junction surface is an important part of the dynamic characteristics of NC machine tools, and it is sometimes the weakest link of the machine tool's dynamic characteristics. The precision of the finite element calculation of the machine tool's dynamic characteristics shall be affected by the junction surface parameters directly. Linear Motion guide is one of the most widely used components of the NC machine tool, and its characteristic is one of the most important components of the performances of the NC machine tool. The HSR series of linear motion guides are taken as the object of the paper, and its static and dynamic characteristics are studied. And the parameters of static and dynamic characteristics of HSR, such as static stiffness, natural frequency and modal shape are obtained. The accuracy of the finite element analysis mode is verified, which establishes the foundation for the dynamics analysis of machine tool.
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Xu, Chuanbo, Mao-Ru Chi, Liangcheng Dai, Yiping Jiang und Zhaotuan Guo. „Study of Vertical Characteristics with Changes in Prepressure of Rubber Pad Used by High-Speed EMU“. Advances in Materials Science and Engineering 2020 (17.06.2020): 1–13. http://dx.doi.org/10.1155/2020/8257286.
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Rubber spring plays an important role in improving train performance, so the study of rubber spring is one of the focuses of train dynamics. The vertical characteristic parameters of rubber spring are affected by prepressure significantly, as a result of varying parameters of static stiffness, dynamic stiffness, periodic energy consumption, damping coefficient, and so on. In order to use the theoretical method to calculate the precise static stiffness and predict the dynamic characteristics and to reduce the workload of the rubber spring performance test, this paper takes the annular rubber pad as an example to study with different prepressures. In this paper, the convexity coefficient correction formula (simply called the CCCF) for static stiffness calculation and the dynamic fiducial conversion coefficient (simply called the DFCC) method based on different prepressures are proposed. Through further analysis, the accuracy of CCCF and DFCC is proved both theoretically and experimentally. The results have shown precise prediction of the variation of prepressure on rubber spring parameters by using CCCF and DFCC and can be used as the reference of accurate vertical dynamic-static characteristics of the rubber spring.
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Radosz, Wojciech, Grzegorz Pawlik und Antoni C. Mituś. „Characterization of Monte Carlo Dynamic/Kinetic Properties of Local Structure in Bond Fluctuation Model of Polymer System“. Materials 14, Nr. 17 (31.08.2021): 4962. http://dx.doi.org/10.3390/ma14174962.
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We report the results of the characterization of local Monte Carlo (MC) dynamics of an equilibrium bond fluctuation model polymer matrix (BFM), in time interval typical for MC simulations of non-linear optical phenomena in host-guest systems. The study contributes to the physical picture of the dynamical aspects of quasi-binary mosaic states characterized previously in the static regime. The polymer dynamics was studied at three temperatures (below, above and close to the glass transition), using time-dependent generalization of the static parameters which characterize local free volume and local mobility of the matrix. Those parameters play the central role in the kinetic MC model of host-guest systems. The analysis was done in terms of the probability distributions of instantaneous and time-averaged local parameters. The main result is the characterization of time scales characteristic of various local structural processes. Slowing down effects close to the glass transition are clearly marked. The approach yields an elegant geometric criterion for the glass transition temperature. A simplified quantitative physical picture of the dynamics of guest molecules dispersed in BFM matrix at low temperatures offers a starting point for stochastic modeling of host-guest systems.
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Sheng, Dong Fa. „Dynamical Behaviors of Nonlinear Viscoelastic Piles with Damage“. Advanced Materials Research 479-481 (Februar 2012): 234–39. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.234.
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Base on the constitutive model expressed by convolution method for viscoelastic materials with damage, the initial-boundary-value problem analyzing static-dynamic behaviors of homogeneous, isotropic viscoelastic. Tiimoshenko beams with damage, placed on a viscoelastic foundation, is formulated under the case of finite deflections. And we adopt the model to simulate the dynamical behaviors of viscoelastic piles with damage placed on a viscoelastic foundation. The numerical methods in nonlinear dynamics are used to solve the simplified systems. The phase-trajectory diagrams, Poincare sections and bifurcation diagrams are all obtained. The influences of the material parameters of pile and foundation and load parameter on the dynamic behavior of the nonlinear system are investigated in detail.
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Andreev, Vadim. „Style Evolution: Space and Movement in Longfellow’s Lyrical Poems“. Bakhtiniana: Revista de Estudos do Discurso 16, Nr. 3 (September 2021): 166–86. http://dx.doi.org/10.1590/2176-457350035.
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ABSTRACT Variance of individual style over time and the tendencies in style evolution are important issues in modern linguistics. This paper investigates how parameters of space and movement categorization were deployed by the famous American poet H.W. Longfellow at different stages of his creative career. The attention is focused on lexical units with spatial meaning. The analysis revealed significant changes in (i) the structure of space, (ii) the ratio of horizontal vs. vertical relations of objects, statics vs. dynamics, and (iii) the role of a human being in poetic space. The early verse represents the world as a balanced unity, which then turns into a more complex system with two strata of reality. At the final stage of Longfellow’s creative career, space in his poetic world is integrated again but now acquires a new structural organisation that is different, to a certain extent, from that of his early period.
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Shin, J. K., und Yuri Mansury. „Emerging Spatiotemporal Patterns from Discrete Migration Dynamics of Heterogeneous Agents“. Discrete Dynamics in Nature and Society 2010 (2010): 1–13. http://dx.doi.org/10.1155/2010/348747.
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We propose a discrete agent-based model to investigate the migration dynamics of heterogeneous individuals. Compatibility among agents of different types is expressed in terms of homophily parameters capturing the extent to which similar individuals are attracted to, or dissimilar individuals are repelled by, each other. Based on agent-based simulations, we establish the connection between emerging spatiotemporal patterns and the homophily parameters. Key results are presented in a novel phase diagram, which reveals a wide range of spatial patterns including the cell, worm, herd, amoeba, and swarm modes under the dynamic regime and the separation, ghetto, and integration modes under the stationary one. Our model thus provides a generalized framework encompassing both static equilibrium and nonstationary systems to investigate the impact of agent heterogeneity on population dynamics. We demonstrate potential applications of our model to social systems using sexual segregation of ungulate habitats as a case study.
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Jia, Chenhui, Zhiwu Cui, Shijun Guo und Wensuo Ma. „Research on dynamic characteristics of gas film of spherical hybrid gas bearings based on computational fluid dynamics“. Transactions of the Canadian Society for Mechanical Engineering 44, Nr. 1 (01.03.2020): 23–37. http://dx.doi.org/10.1139/tcsme-2018-0134.
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A realizable k–ε turbulence model for spherical spiral groove hybrid gas bearing films was established based on computational fluid dynamics (CFD). A six degrees of freedom passive grid was used to calculate the gas film pressure distribution, bearing capacity, and dynamic characteristic coefficients numerically. The gas flow field dynamic and static pressure coupling mechanism was studied. The effects of the rotation speed, gas film thickness eccentricity ratio, and gas supply pressure on the dynamic and static pressure bearing capacity, and dynamic characteristic coefficients during operation were analyzed as a method of research into the mechanical mechanisms of gas bearing stability. The CFD calculation analysis can simulate the complex gas flow in the transient flow field of the gas film and determine reasonable operation parameters to optimize the dynamic and static pressure coupling effects, which can improve the gas film bearing capacity, dynamic characteristics, and operational stability of gas bearings.
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Nguyen, Xo Van. „Design calculations and simulation dynamics of banana screen“. Journal of Mining and Earth Sciences 61, Nr. 2 (29.04.2020): 50–57. http://dx.doi.org/10.46326/jmes.2020.61(2).06.
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The banana screen is a device used to classify materials widely used in screenings factories at home and abroad. It's working ability depends on many factors (kinematic parameters, technological parameters, particle size, and material moisture,...). If using the traditional method to determine suitable parameters to reach high efficiency, it is very difficult. Because the calculated results are not accurate, it takes a designer much time and makes the manufacturing cost increase. In this study, the author uses the computer software CREO, ADAMS, ANSYS to design and simulate the dynamics of the screen. The results of study are the dynamic parameters of the screen during the working time and are shown in different graphs (Elastic pillow deformation of spring; the force exerted on the elastic pillow; the center velocity of vibration box; center acceleration of vibration box; static energy of vibrates box; translational momentum of vibration box; moment momentum of vibration box). These results also can be applied to design banana screens, which have a high capacity and efficiency as well as a long lifetime.
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Muscolino, Giuseppe, Alba Sofi und Filippo Giunta. „Dynamics of structures with uncertain-but-bounded parameters via pseudo-static sensitivity analysis“. Mechanical Systems and Signal Processing 111 (Oktober 2018): 1–22. http://dx.doi.org/10.1016/j.ymssp.2018.02.023.
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Lemaalem, M., A. Derouiche, S. EL Fassi und H. Ridouane. „The influence of temperature and density on the microscopic structure and dynamics of long polymer chains: Molecular dynamics and dissipative particle dynamics modeling“. International Journal of Computational Materials Science and Engineering 06, Nr. 03 (September 2017): 1750023. http://dx.doi.org/10.1142/s2047684117500233.
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Long polymer chains that mainly exhibit thermoplastic properties are recognized to demonstrate excellent thermal and mechanical features at the molecular level. For the purpose of facilitating its study, we present the results of a coarse-grained Molecular Dynamics (MD) and Dissipative Particle Dynamics (DPD) simulations under the Canonical ensemble (NVT) conditions. For each simulation method, the structure, static and dynamic properties were analyzed, with particular emphasis on the influence of density and temperature on the equilibrium of the polymer. We find, after correcting the Soft Repulsive Potential (SRP) parameters used in DPD method, that both simulation methods describe the polymer physics with the same accuracy. This proves that the DPD method can simplify the polymer simulation and can reproduce with the same precision the equilibrium obtained in the MD simulation.
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Xu, Dan, und Zhixin Feng. „Research on Dynamic Modeling and Application of Kinetic Contact Interface in Machine Tool“. Shock and Vibration 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/5658181.
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A method is presented which is a kind of combining theoretic analysis and experiment to obtain the equivalent dynamic parameters of linear guideway through four steps in detail. From statics analysis, vibration model analysis, dynamic experiment, and parameter identification, the dynamic modeling of linear guideway is synthetically studied. Based on contact mechanics and elastic mechanics, the mathematic vibration model and the expressions of basic mode frequency are deduced. Then, equivalent stiffness and damping of guideway are obtained in virtue of single-freedom-degree mode fitting method. Moreover, the investigation above is applied in a certain gantry-type machining center; and through comparing with simulation model and experiment results, both availability and correctness are validated.
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Gusella, Vittorio, Giuseppina Autuori, Patrizia Pucci und Federico Cluni. „Dynamics of Nonlocal Rod by Means of Fractional Laplacian“. Symmetry 12, Nr. 12 (24.11.2020): 1933. http://dx.doi.org/10.3390/sym12121933.
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The use of fractional models to analyse nonlocal behaviour of solids has acquired great importance in recent years. The aim of this paper is to propose a model that uses the fractional Laplacian in order to obtain the equation ruling the dynamics of nonlocal rods. The solution is found by means of numerical techniques with a discretisation in the space domain. At first, the proposed model is compared to a model that uses Eringen’s classical approach to derive the differential equation ruling the problem, showing how the parameters used in the proposed fractional model can be estimated. Moreover, the physical meaning of the model parameters is assessed. The model is then extended in dynamics by means of a discretisation in the time domain using Newmark’s method, and the responses to different dynamic conditions, such as an external load varying with time and free vibrations due to an initial deformation, are estimated, showing the difference of behaviour between the local response and the nonlocal response. The obtained results show that the proposed model can be used efficiently to estimate the response of the nonlocal rod both to static and dynamic loads.
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Yang, Hua, Takeshi Takaki und Idaku Ishii. „Simultaneous Dynamics-Based Visual Inspection Using Modal Parameter Estimation“. Journal of Robotics and Mechatronics 23, Nr. 1 (20.02.2011): 180–95. http://dx.doi.org/10.20965/jrm.2011.p0180.
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In this study, we introduce the concept of dynamicsbased visual inspection with High-Frame-Rate (HFR) video analysis as a novel non-destructive active sensing method for verifying dynamic properties of a vibrating object. The HFR video is used for determining the structural dynamic properties of an object, such as its resonant frequencies and mode shapes, which can be estimated as modal parameters by modal analysis only when the object is excited. By improving and implementing a fast output-only modal parameter estimation algorithm on a real-time 2000-fps vision platform, the modal parameters of an excited object are simultaneously estimated as its input-invariant dynamic properties for dynamics-based visual inspection evenwhen the objects undergo different excitation conditions. Our simultaneous 2000-fps visual inspection system can facilitate non-destructive and longterm monitoring of the structures of beam-shaped objects vibrating at dozens or hundreds of hertz, and it can detect small changes in the dynamic properties of these objects caused by internal defects such as fatigue cracks in real time, even when their static appearances are similar. To demonstrate the performance of the proposed 2000-fps simultaneous dynamics-based visual inspection approach, the resonant frequencies and mode shapes for beam-shaped cantilevers with different artificial cracks and weights, excited by human finger tapping, were estimated in real time.
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GOLDSTEIN, R. S., M. F. ZIMMER und Y. OONO. „MODELING MESOSCALE DYNAMICS OF FORMATION OF δ′-PHASE IN Al-Li ALLOYS“. Modern Physics Letters B 07, Nr. 16 (10.07.1993): 1083–94. http://dx.doi.org/10.1142/s0217984993001077.
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A mesoscale minimal model study of the α−δ′ two-phase system is presented. A minimal model free energy is introduced which reveals universal features of the ordering dynamics of the disordered into the L1 2 ordered state. Static phenomenological parameters of the minimal model are chosen to reproduce the equilibrium phase diagram, and dynamical ones are chosen to reproduce recent experimental scattering results by H. Chen’s group.