Tribological behavior of the Inconel X-750 alloy disk subjected to fretting against the GCr15 steel ball was investigated in an ambient laboratory air with relative humidity of 55–65%. A ...high-frequency oscillating Optimol SRV 4 tribometer was employed to execute dry fretting tests in the partial and gross slip regimes under constant 100 N normal load. Tests were carried out for 10, 30, and 90 minutes, and the friction forces vs. displacement amplitudes were monitored during the test duration. Posttest examinations were conducted utilizing advanced tools such as 3D optical surface profiler, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The main objective was to obtain wear scar evolutions, frictional properties, and degradation mechanisms under the different running conditions over time. It was found that fretting wear behaviors of friction pairs were strongly influenced by fretting regimes. Degradation evolutions were greatly influenced by fretting time during partial slip regimes, i.e., evolving from asperity deformation and slight damage to the fatigue crack and material transfer. However, the combination of adhesive, abrasive, delamination, and wear oxidation mechanisms was repeated during the entire gross slip fretting process.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Within the statistical model, the net strangeness conservation and incomplete total strangeness equilibration lead to the suppression of strange particle multiplicities. Furthermore, suppression ...effects appear to be stronger in small systems. By treating the production of strangeness within the canonical ensemble formulation we developed a simple model which allows to predict the excitation function of K+/π+ ratio in nucleus–nucleus collisions. In doing so we assumed that different values of K+/π+, measured in p + p and Pb + Pb interactions at the same collision energy per nucleon, are driven by the finite size effects only. These predictions may serve as a baseline for experimental results from NA61/SHINE at the CERN SPS and the future CBM experiment at FAIR.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Broadband Acousto-optic Amplitude Demodulator Gasanov, A. R.; Gasanov, R. A.; Rustamov, A. R. ...
Radioelectronics and communications systems,
02/2023, Volume:
66, Issue:
2
Journal Article
Peer reviewed
The scientific and practical significance of the synthesis of demodulators in solving the problem of monitoring unknown radio emissions has been substantiated. Features of the photoelastic effect are ...discussed in the context of constructing an amplitude demodulator. A mathematical model of the signal generation process at the output of the demodulator has been developed. It is shown that the output signal of this model is a copy of the information contained in the radio signal at the input of demodulator. In this case, the amplitude demodulator also performs the function of a low-pass filter with a characteristic cutoff frequency. A method for calculating the demodulator cutoff frequency based on the transient response is proposed. A breadboard of acousto-optic amplitude demodulator based on Bragg’s cell with the central frequency of 80 MHz has been created. A number of experimental studies were conducted to verify the established concepts. The demodulation processes of signals with amplitude and pulse modulation were considered. It has been proved by experiment that the acousto-optic amplitude demodulator reproduces information with accuracy sufficient for practice. An example of determining the cutoff frequency of acousto-optic amplitude demodulator by employing the shape of the output pulse is presented.
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FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The paper considers the schematic diagram and operation algorithm of acoustooptic processor (AOP), the main assemblies of which are acoustooptic modulator (AOM), laser and photodetector (PD). Using ...the mathematical simulation, it has been shown that the signal at the AOP output contains information about the characteristics of AOM, laser and PD. The possibility of investigating the characteristics of one of the above assemblies with the known parameters of the other two by using the AOP response on determinate input action in the form of rectangular pulse has been established. A brief review of the known methods for measuring the parameters of PD and laser is presented including certain limitations of their applications. The theoretical substantiation of the possible use of AOP peculiarities for measuring the PD inertia parameters is presented. A formula for the calculation of the AOP output response to rectangular input action is proposed that makes it possible to estimate separately the time of optical beam crossing by the elastic wave packet and PD inertia. In addition, it has been proved that the configuration of cross-section of laser beam and the distribution law of power flux density in this beam could be determined on the basis of AOP peculiarities. To this end, a pulse of short duration is fed to the AOP input. Results of theoretical investigations were validated by numerical calculations and confirmed by experimental measurements.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The model of perishable queueing-inventory system with server vacations is studied. Upon service completion, server takes vacation if there are no customers in the queue and it starts service at the ...end of the vacation if the number of customers in the system exceeds some threshold; otherwise, it takes new vacation. Exact and approximate methods are proposed to calculate the characteristics of the system.
The authors propose a mathematical model for a multi-channel queueing system with feedback in which one part of calls instantaneously enters the system for repeated service and the other part either ...retries in some random time or finally leaves the system. The behavior of the serviced calls is randomized. Both exact and asymptotic methods are developed to calculate the characteristics of the proposed model. The results of numerical experiments are presented.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The Markov model of a two-stage queueing network with feedback is proposed. Poisson flows arrive to both stages from outside. A part of already serviced calls at the first node instantaneously enter ...the second node (if there is free space here) while the other calls leave the network. After the service is completed at the second node, there are three possibilities: (i) the call leaves the network; (ii) it instantaneously feeds back to the first node (if there is free space here); (iii) it feeds back to the first node after some delay in orbit. All feedbacks are determined by known probabilities. Both nodes have finite capacities. The mathematical model of the investigated network is a three-dimensional Markov chain, and a hierarchical space merging algorithm is developed to calculate its steady-state probabilities. The results of numerical experiments are demonstrated.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The study of multiplicity distributions of identified particles in terms of their higher moments is at the focus of contemporary experimental and theoretical studies. In a thermalized system ...combinations of these moments are directly related to the Equation of State (EoS) through variations of the thermodynamic pressure with respect to changes in the chemical potential μQ, associated with a conserved charge Q. The ultimate goal of the experimental measurements in relativistic nuclear collisions is, by systematics comparison to the ab initio theoretical calculations, to probe the dynamics of genuine phase transitions between a hadron gas and the quark-gluon plasma. However, the comparison between experiment and theory is far from trivial, because several non-dynamical fluctuations need to be controlled prior to a meaningful comparison to theoretical predictions. In this report we present quantitative estimates for these non-dynamical contributions using the Canonical Ensemble (CE) formulation of the statistical mechanics. Together with the analytical formulas we provide also results from Monte Carlo simulations within the CE and compare our predictions with the corresponding measurements from the STAR experiment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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