Wyniki wyszukiwania - BazTech

1

Vibration control of a rotating shaft by passive mass-spring-disc dynamic vibration absorber

Nguyen Duy Chinh

Archive of Mechanical Engineering

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2020

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LXVII, nr 3

279--297

EN

Shaft is a machine element which is used to transmit rotary motion or torque. During transmission of motion, however, the machine shaft doesn’t always rotate with a constant angular velocity. Because of unstable current or due to sudden acceleration and deceleration, the machine shaft will rotate at a variable angular velocity. It is this rotary motion that generates the moment of inertial force, causing the machine shaft to have torsional deformation. However, due to the elasticity of the material, the shaft produces torsional vibration. Therefore, the main objective of this paper is to determine the optimal parameters of dynamic vibration absorber to eliminate torsional vibration of the rotating shaft that varies with time. The new results in this paper are summarized as follows: Firstly, the author determines the optimal parameters by using the minimum quadratic torque method. Secondly, the maximization of equivalent viscous resistance method is used for determining the optimal parameters. Thirdly, the author gives the optimal parameters of dynamic vibration absorber based on the fixed-point method. In this paper, the optimum parameters are found in an explicit analytical solutions, helping the scientists to easily find the optimal parameters for eliminating torsional vibration of the rotating shaft.

2

Notes on multidimensional fixed-point theorems

Akhadkulov H., Noorani S. M., Saaban A. B., Alipiah F. M., Alsamir H.

Demonstratio Mathematica

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2017

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Vol. 50, nr 1

360--374

EN

In this paper we prove the existence and uniqueness of coincident (fixed) points for nonlinear mappings of any number of arguments under a (ψ ,θ, φ)-weak contraction condition without O-compatibility. The obtained results extend, improve and generalize some well-known results in the literature to be discussed below. Moreover, we present an example to show the efficiency of our results.

3

Banach fixed-point theorem in semilinear controllability problems – a survey

Klamka J., Babiarz A., Niezabitowski M.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2016

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Vol. 64, nr 1

21--35

EN

The main aim of this article is to review the existing state of art concerning the complete controllability of semilinear dynamical systems. The study focus on obtaining the sufficient conditions for the complete controllability for various systems using the Banach fixedpoint theorem. We describe the results for stochastic semilinear functional integro-differential system, stochastic partial differential equations with finite delays, semilinear functional equations, a stochastic semilinear system, a impulsive stochastic integro-differential system, semilinear stochastic impulsive systems, an impulsive neutral functional evolution integro-differential system and a nonlinear stochastic neutral impulsive system. Finally, two examples are presented.

4

Performance of a new set of In, Sn and Zn Temperature Fixed-Points

Ahmed M. G., Ali K.

Metrology and Measurement Systems

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2007

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Vol. 14, nr 2

269-274

EN

A comparison of a new set of "In, Sn and Zn" temperature fixed-points on the International Temperature Scale of 1990 (ITS-90) was carried out at the National Institute of Standards (NIS - Egypt). The new set was manufactured by Hart Scientific - USA. The comparison was performed to measure their performance and capabilities in calibrating Standard Platinum Resistance Thermometers (SPRTs). This comparison was carried out using four calibrated SPRTs and the reference set of "In, Sn and Zn". The used reference set was manufactured by National Physical Laboratory (NPL-England). Full description and measurements made to the two sets are presented. Measurements showed good results and some agreement between the two sets. The differences between cells of the new set and reference cells were well within 2 mK. This showed their capabilities and the possibility of using them in calibrating SPRTs.

5

An algebra of data flows

Winkowski J.

Prace Instytutu Podstaw Informatyki Polskiej Akademii Nauk

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1999

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nr 880

3-39

EN

An algebra of processes is proposed in which processes are modelled in terms of data rather than events. Structures representing processes are similar to the labelled event structures of Winskel (1982), but they denote flows of data. For processes represented in such a way operations similar to those of CCS (the Calculus of Communicating Systems as developed by Milner (1980) are defined and their fundamental properties are stated.

PL

Praca zawiera propozycję pewnej algebry procesów, w której procesy opisuje się za pomocą danych a nie zdarzeń. Struktury reprezentujące procesy przypominają etykietowane struktury zdarzeń Winskela (1982), ale opisują one przepływy danych. Na procesach tak reprezentowanych definiuje się operacje, podobne do operacji zaproponowanego przez Milnera (1980) rachunku komunikujących się systemów CCS.