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1
Content available remote Resonance and Some of its Effects in Practice
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EN
We often meet with the phenomenon of resonance in professional practice at times when it also causes undesirable results. Insulation damage or overheating and destruction of the device due to excessive load current may occur. While searching for the causes of the failures which are related to resonance, the basic principles of its occurrence and suppression must be recalled. This is very important today, when the number of nonlinear loads and power electronics devices constantly increases.
PL
Ze zjawiskiem rezonansu spotykamy się często w praktyce zawodowej w momentach kiedy przynosi on również niepożądane skutki. Ulega uszkodzeniu izolacja, gdy płyną zbyt duże prądy powodujące przegrzanie i zniszczenie urządzenia. Szukając przyczyny awarii związanych z rezonansem należy pamiętać o podstawowych zasadach jego powstawania oraz tłumienia. Jest to bardzo istotne w dobie wzrastającej liczby odbiorników nieliniowych oraz urządzeń energoelektroniki.
2
Content available remote Rezonans i niektóre jego skutki w praktyce
100%
PL
Ze zjawiskiem rezonansu spotykamy się często w praktyce zawodowej w momentach kiedy przynosi on również niepożądane skutki. Ulega uszkodzeniu izolacja, gdy płyną zbyt duże prądy powodujące przegrzanie i zniszczenie urządzenia. Szukając przyczyny awarii związanych z rezonansem należy pamiętać o podstawowych zasadach jego powstawania oraz tłumienia. Jest to bardzo istotne w dobie wzrastającej liczby odbiorników nieliniowych oraz urządzeń energoelektroniki.
EN
We often meet with the phenomenon of resonance in professional practice at times when it also causes undesirable results. Insulation damage or overheating and destruction of the device due to excessive load current may occur. While searching for the causes of the failures which are related to resonance, the basic principles of its occurrence and suppression must be recalled. This is very important today, when the number of nonlinear loads and power electronics devices constantly increases.
EN
Translational spectroscopy stimulated the investigation of shape resonances in the electronic ground state of HeH(+) a number of years ago. Subsequent spectroscopic studies have increased the accuracy of these experimental data. Theoretical investigations require an extremely accurate potential energy curve over an extended range of internuclear separation. The calculation by Kołos proved invaluable in identifying these states and continues to be the standard to which improvements are added. The accurate characterization of many isolated shape resonances may be necessary so convenient techniques are required. Test functions are often used to create a boundary condition that converts this problem in the continuum to a discrete state calculation. The resulting eigenvalue search is efficient and convenient to automate. The associated widths are usually found by other techniques. It is shown here that the eigenvalue calculation implies a width if one convenient and easily satisfied requirement is met. Two versions of this result are applied to selected experimantal data for HeH(+).
Open Physics
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2012
|
tom 10
|
nr 4
1013-1017
EN
In this work, we explore more applications of the simplified form of the bilinear method to the seventhorder Caudrey-Dodd-Gibbon (CDG) and the Caudrey-Dodd-Gibbon-KP (CDG-KP) equation. We formally derive one and two soliton solutions for each equation. We also show that the two equations do not show resonance.
5
80%
EN
In this work, we consider a fractional nonlinear vibration system of Duffing type with harmonic excitation by using the fractional derivative operator -∞−1Dαt and the averaging method. We derive the steady-state periodic response and the amplitude-frequency and phase-frequency relations. Jumping phenomena caused by the nonlinear term and resonance peaks are displayed, which is similar to the integer-order case. It is possible that a minimum of the amplitude exists before the resonance appears for some values of the modelling parameters, which is a feature for the fractional case. The effects of the parameters in the fractional derivative term on the amplitude-frequency curve are discussed.
6
Content available remote A topological version of the Ambrosetti-Prodi theorem
80%
EN
The existence of at least two solutions for nonlinear equations close to semilinear equations at resonance is obtained by the degree theory methods. The same equations have no solutions if one slightly changes the right-hand side. The abstract result is applied to boundary value problems with specific nonlinearities.
7
Content available remote Piezoelectric material characterization by acoustic methods
80%
EN
Two characterization methods of piezoelectric materials based on acoustic measurements are presented. Their main objective is to identify the entire set of electromechanical properties of piezoelectric materials from a single sample. In order to characterize new materials like single-crystals with small dimensions, the first section of the paper presents an identiffication protocol based on the study of the resonance spectra of parallelepipeds. The second characterization method is performed by means of the measurement of the transmission coefficients of plane waves propagating through an immersed plate. It is is suitable for the determination of the properties of bulk piezoelectric ceramics.
8
Content available Rezonans a rejestry głosowe
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EN
Resonance and voice registrations are one of the important factors of vocal technique. They include the wide range of issues which recognition, and skilful usage causes full and conscious voice operation. Working out proper skills of using voice resonance with a reference to free conscious operation of voice registration is not only a subject of long term process of learning to sing, but also is the center of attention during continuous work on the voice of every vocalist. Definitions of notions, division of resonance chambers and voice registrations their functions and a role and dependence in the process of phonation – there subject of the work.
EN
Six resonances of the helicopter body standing on the airport apron and at least two resonances of the free helicopters the frequencies of which are within the range of basic loadings by the helicopter rotor is called (8+) model. It was proposed to identify (8+) model with the use of resonance tests. It was indicated that (8+) model allows for detuning the resonances from the frequency of working loads, tracing the process of moving through resonances as well as taking off and landing. The paper presents: example of a helicopter on a test rig and visible vibrations inductors; induction of resonance vibrations, induction of resonance vibrations with the forms of pitching, yawing, rolling; induction of resonance vibrations with the forms of pitching with opposite pylon yawing and tipping with opposite pylon yawing; model of helicopter resonances; the multiplication of the resonance amplitude for various velocities of moving through with visible growth of the resonance frequency and reduction of vibrations amplitude; change of the frequencies at the taking off and landing.
10
Content available remote Integrability of coupled KdV equations
80%
Open Physics
|
2011
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tom 9
|
nr 3
835-840
EN
The integrability of coupled KdV equations is examined. The simplified form of Hirota’s bilinear method is used to achieve this goal. Multiple-soliton solutions and multiple singular soliton solutions are formally derived for each coupled KdV equation. The resonance phenomenon of each model will be examined.
EN
The effects of axial compressive forces on free vibration frequencies of rotating machine support beams are investigated taking into account their geometric stiffness. One class of structures that has economic and strategic importance is the base of machines, which is excited by vibrations induced by the supported equipment. These vibrations can affect the structures or, more generally, may generate damage to the supported equipment and the quality of production. They may also render human working conditions difficult. In the current work, these effects are studied via mathematical modeling, numerical simulation and experimental evaluation.
EN
This article clarifies the developments in the understanding of pastoral care. On the basis of a letter on pastoral care, presented by the German bishops, the article verifies the thesis that voluntary work in the church can be understood as a co-sponsor of pastoral care.
EN
With the exponential growth of IoT (Internet of Things), Industry 4.0, and electrical vehicles, there is a growing need for flexible energy sources. Wireless energy transfer is becoming increasingly important in this context, as it enables physical devices to be more flexible and allows for the simultaneous powering of multiple loads. This study presents a wireless energy transfer system that uses solenoid coils in inductive resonant mode. The system is configured in a point multipoint setup, with a circular transmitter coil and two identical circular receiver coils placed inside the transmitter. We use mathematical modeling to develop circuit theory models and identify the most efficient topology for the system. In addition, we propose a simple and cost-effective self-oscillating electronic converter design with two switches for system supply. Our numerical and experimental results demonstrate that the proposed system is viable and functional, achieving a power output of 1.7 W and efficiency of 27%.
EN
The prismatic structures for excitation surface plasmon polariton and waveguide modes resonances were investigated. The first structure consists of a glass prism and thin metallic layer deposited on the prism. The second one includes an additional dielectric layer. Plasmon polariton resonance can be observed only for TM polarization at finely tuned structure parameters. Waveguide modes resonance is possible for both polarizations in the presence of the dielectric layer. We show that the first structure has the highest sensitivity of angle minimum reflectivity, whereas the second one has the highest reflectivity sensitivity to the probed liquid refractive index changes.
15
80%
Open Physics
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2013
|
tom 11
|
nr 1
143-146
EN
In this work we study an eighth-order KdV-type equations in (1+1) and (2+1) dimensions. The new equations are derived from the KdV6 hierarchy. We show that these equations give multiple soliton solutions the same as the multiple soliton solutions of the KdV6 hierarchy except for the dispersion relations.
EN
Results of dielectric spectroscopy of quartzite slate are presented. New type of a porous matrix based on quartzite schist was described. The matrix was filled by a ferroelectric TGS-crystal. The phase transition of the TGS bulk was shown to occur and compared with the phase transition of the component quartzite schist filled with TGS (QSM-TGS). The resonance phenomena in the QSM were shown and described from the point of view filled material.
EN
In this paper, 3D numerical analysis of unsteady flow forces acting on the thermowell of steam temperature sensor is presented. According to that purpose, the CFD+CSD (computational fluid–solid dynamics) approach has been used. The nonstationary of fluid acting on the thermowell such as: Strouhal frequency, amplitude of pressure, structure of vortex, peak of pressure, field of pressure, field of velocity, etc. are studied analytically and numerically. There have been examined two cases of flow with changing both temperature, pressure and mass flow rate (operating daily and night in the unit with capacity of 380 MWe). In accordance with the standards ASME PTC 19.3 TW-2010 the possibility of entry into resonance has been examined.
PL
Na przykładzie rezonansowego napędu mechanizmu krosna tkackiego przedstawia się ideę zastąpienia napędu wymuszonego napędem wykorzystującym drgania swobodne określonego elementu maszyny. W przypadku krosna takim elementem może być nicielnica, gdzie technologicznie okresowe napinanie nitek osnowy, dotychczas dla nich szkodliwe, przekształcono w użyteczne, a mianowicie wykorzystywane do wspomagania cyklicznego ruchu nicielnic napędzanych elektromagnetycznym wzbudnikiem. Wzbudnik dodaje jedynie energię równą dyssypowanej przez układ, co czyni taki napęd najekonomiczniejszym, a także atrakcyjnym z uwagi na inne wskaźniki eksploatacyjne.
EN
On an example of the new resonance dobby mechanism is shown an new idea of the loom in which main widely known cam mechanism are replaced with mechanism working in synchronised free vibration range. In the loom such mechanism can be e.g. a dobby, in which the periodic stretching of warp - a destructive phenomenon - could be transformed into useful and serviceable to support periodic movement of the heald frame derived by an electromagnetic exciter. The exciter adds only the dissipated of the vibrating dobby-system, what makes such power feed the most economical one, as well as in view of other terotechnological aspects.
EN
We investigate the influence of the motion of fluid flushing the cutter of a well drilling column, and the angular rotational velocity upon dynamic characteristics of its flexural vibrations. We take into account the nonlinear elastic features of column material. As a base of the research we took the Galerkin method and the Van der Pol method. Combining those two methods made possible to obtain the relations describing the main parameters of the dynamical process In both nonresonance and resonance case.
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