mechanical change
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2021 ◽  
Vol 11 (22) ◽  
pp. 10669
Author(s):  
Marcin Nowicki ◽  
Witold Respondek

We give a classification of linear nondissipative mechanical control system under mechanical change of coordinates and feedback. First, we consider a controllable case that is somehow a mechanical counterpart of Brunovský classification, then we extend the result to all linear nondissipative mechanical systems (not necessarily controllable) which leads to a mechanical canonical decomposition. The classification of Lagrangian systems is given afterwards. Next, we show an application of the classification results to the stability and stabilization problem and illustrate them with several examples. All presented results in this paper are expressed in terms of objects on the configuration space Rn only, while the state-space of a mechanical control system is Rn×Rn consisting of configurations and velocities.


2021 ◽  
Vol 10 (3) ◽  
pp. 24-30
Author(s):  
S. Piltyay ◽  
A. Bulashenko ◽  
V. Shuliak ◽  
O. Bulashenko

In this article we present the results of mathematical simulation, development and optimization of a waveguide polarizer with a diaphragm and pins. A mathematical model was developed using the proposed approach on the example of a waveguide polarizer with one diaphragm and two pins. The diaphragm and pins were modeled as inductive or capacitive elements for two types of linear polarization of the fundamental modes. The applied model uses a wave scattering matrix. The total matrix of a polarizer was obtained using wave matrices of transmission of individual elements of the device structure. Using the elements of the common S-parameters the electromagnetic characteristics of the device, which is considered, were obtained. To check the performance of the developed mathematical model, it was simulated in a software using the finite element technique in the frequency domain. The designed structure of the polarizer is adjustable due to mechanical change in the length of the pins. The developed waveguide polarizer with one diaphragm and two pins provides a reflection coefficient of less than 0.36 and a transmission coefficient of more than 0.93 for two types of polarizations. Therefore, a new theoretical method was developed in the article for analysis of scattering matrix elements of a waveguide polarizer with diaphragms and pins. It can also be used for the development of new tunable waveguide polarizers, filters and other components with diaphragms and pins.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2594
Author(s):  
Marta Harničárová ◽  
Jan Valíček ◽  
Milena Kušnerová ◽  
Zuzana Palková ◽  
Ivan Kopal ◽  
...  

The formulation of the Hall–Petch relationship in the early 1950s has raised immense interest in studying the influence of the grain size of solid materials on their properties. Grain refinement can be achieved through extreme deformation. In the presented study, Equal-Channel Angular Pressing (ECAP) was successfully applied to produce an ultrafine-grained microstructure in a pure commercial Cu of 99.9 wt%. Samples were processed by ECAP at 21 °C for six passes via route A. A new equation of equilibrium that allows the exact determination of the number of extrusions and other technological parameters required to achieve the desired final grain size has been developed. The presented research also deals, in a relatively detailed and comparative way, with the use of ultrasound. In this context, a very close correlation between the process functions of extrusion and the speed of longitudinal ultrasonic waves was confirmed.


2020 ◽  
Vol 319 (6) ◽  
pp. R724-R732 ◽  
Author(s):  
Jerry Yu

Conventional one-sensor theory (one afferent fiber connects to a single sensor) categorizes the bronchopulmonary mechanosensors into the rapidly adapting receptors (RARs), slowly adapting receptors (SARs), or intermediate adapting receptors (IARs). RARs and SARs are known to sense the rate and magnitude of mechanical change, respectively; however, there is no agreement on what IARs sense. Some investigators believe that the three types of sensors are actually one group with similar but different properties and IARs operate within that group. Other investigators (majority) believe IARs overlap with the RARs and SARs and can be classified within them according to their characteristics. Clearly, there is no consensus on IARs function. Recently, a multiple-sensor theory has been advanced in which a sensory unit may contain many heterogeneous sensors, such as both RARs and SARs. There are no IARs. Intermediate adapting unit behavior results from coexistence of RARs and SARs. Therefore, the unit can sense both rate and magnitude of changes. The purpose of this review is to provide evidence that the multiple-sensor theory better explains sensory unit behavior.


2020 ◽  
Vol 19 (6) ◽  
pp. 1894-1904
Author(s):  
Fan Xie ◽  
Yuxiang Zhang ◽  
Eric Larose ◽  
Aroune Duclos ◽  
Su Chen ◽  
...  

In this article, we present an ultrasonic method based on diffuse ultrasound with successive excitation amplitudes. This method provides amplitude-dependent parameters of diffuse ultrasound using coda wave interferometry, and these parameters can be used to characterize mechanical change in metallic materials. The localized mechanical change caused by an instantaneous 400°C thermal shock in a meter-scale aluminum alloy slab was characterized by measuring the diffuse-wave velocity change and decorrelation coefficient as functions of the excitation amplitude. The potential mechanisms and spatial distribution that cause the observed amplitude-dependent diffuse waveform modification are discussed. Combining the method presented here with complementary approaches will enhance the ability to nondestructively detect early-stage damage in the laboratory or in the field.


2019 ◽  
Vol 118 (3) ◽  
pp. 153-157
Author(s):  
M.John Paul ◽  
S. Muthumani

Our Indian financial industry is giving chances to advancements even with constant endeavors at improving budgetary administrations through the innovative improvement in present day field independent of nationalized and modernized banks in India. The greatest test of banks is that gauge the need of clients and edges the administration advancement effectively. The financial segment has been developing at a quick level in India and tested with client desires, mechanical change and changing the method of activities. The advanced Technology has been assuming a crucial job in the colossal improvement of banking administrations .In the new decade of Banks were encountered a continued development by broadening their client system and client relationship the executives for contending others in the worldwide condition. These mind blowing innovational developments are a motor for animating the improvements and keep up the client reinforcement because of accomplishment. This successful CRM practices is playing as a determined of changing client need s into item and administration advancement by quickening the financial business. The dissemination of data from the dependable client would give more proposal to acquire the advancements quality administration process. The paper is meant to discover the impact and significance of administration developments in banks by the predominance CRM rehearses and the wellsprings of data that brings colossal changes by a compelling administration advancements and greatness conveyance in the new age banks.


2016 ◽  
Vol 64 (2) ◽  
pp. 333-338
Author(s):  
M. Sikoń

Abstract In this work, the Cosserat medium is analyzes as a set of atoms. These atoms are under the action of a mechanical load. The statistical analysis is preceded by a description of a single atom using classical mechanics and quantum mechanics. The behavior of the atoms in the field generated by mechanical change of the interatomic distance is shown as a phenomenon which can explain the Cosserat mechanics in a continuum.


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