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Wyniki wyszukiwania dla: PMSM SPEED REGULATION
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ANALYSIS OF THE POSSIBILITIES OF HIGH SPEED SHAFT BEARING SYSTEM DURABILITY INCREASE
PublikacjaDuring the operation of wind turbines with a gearbox of traditional configuration, a high failure rate of high-speed shaft bearings is observed. Such a high failures frequency is not reflected in standard bearing durability calculation methods, which can be attributed to atypical failure mechanism. To avoid observed problems in the 1.5 MW wind turbine, the modification of the existing bearing system is proposed. Multiple options,...
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Evolutionary sets of safe ship trajectories with speed reduction manoeuvres within traffic separation schemes
PublikacjaIn the previous paper the author presented the evolutionary ship trajectory planning method designed to support Traffic Separation Schemes (TSS). This time the extensions of this method are described which allow to combine evolutionary trajectory planning with speed reduction manoeuvres. On TSS regions with higher than usual density of traffic and smaller distances between ships, the course alterations alone are not always sufficient...
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Marine propeller shaft bearings under low-speed conditions: water vs. oil lubrication
PublikacjaThe bearings used in shipbuilding, hydropower, and water pumps have undergone a metamorphosis in recent decades. Because of environmental regulations, lubrication with grease or mineral oil is prohibited. Thus, the standard solutions include water-lubricated bearings with polymer bushings or sealed systems lubricated with oil. When properly designed, assembled, and operated, bearings can operate reliably for years. However, specific...
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High Speed Milling vibration surveillance with optimal spindle speed based on optimal speeds map
PublikacjaThe paper presents the method of the surveillance of the self-excited chatter vibration. At first, the workpiece modal parameters are estimated based on experimental data which leads to verification of computational model. Then, for selected surface points optimal spindle speeds are calculated. By considering sufficient amount of points it is possible to build a map of optimal spindle speeds. Experimental results show that this...
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Chatter Vibration Surveillance by the Optimal-linear Control of Spindle Speed and Randomly Varying Spindle Speed
PublikacjaW artykule opisano dynamikę procesu skrawania smukłym frezem kulistym. Jako metodę nadzorowania drgań chatter zastosowano zmienną prędkość obrotową wrzeciona. Jest ona dobierna z wykorzystaniem energetycznego wskaźnika jakości co prowadzi do optymalno-liniowego sterowania prędkością obrotową. Dodatkowo zastosowano nadzorowanie drgań chatter poprzez losowo zmienną prędkość obrotową.
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High-Speed Serial Embedded Deterministic Test for System-on-Chip Designs
PublikacjaThe paper presents a high-speed serial interface between external tester and Embedded Deterministic Test (EDT) compression logic hosted by SoC designs. With only a single bidirectional link, the system is capable of feeding distributed heterogeneous cores with hundreds of test channels. Moreover, it synergistically supports EDT bandwidth management to improve the overall test performance. A detailed study indicates a high potential...
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Keratin-Butyrate Scaffolds Promote Skin Wound Healing in Diabetic Rats Through Down-Regulation of IL-1β and Up-Regulation of Keratins 16 and 17
PublikacjaImpaired wound healing particularly in diabetics creates a significant healthcare burden. The study aimed to evaluate the effect of keratin-butyrate fibers (FKDP +0.1%NaBu) in a full-thickness skin wound model in 30 diabetic rats. Physicochemical examination showed that the obtained dressing possesses a heterogeneous structure and butyrate was slowly released into the wound. Moreover, the obtained dressing is nontoxic and supports...
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Integrated Control in High-Speed Networks Using Constrained Model Predictive Control
PublikacjaThis paper studies congestion control in high-speed communication networks using Model Predictive Control (MPC). Network traffic is assumed to consist of best-effort and priority traffic sources. An integrated controller consisting of two control parts is designed. The controller calculates the capacity for priority sources and the input rate of best-effort sources. MPC is desirable as it can take into account the constraints on...
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Light-Dependent Protochlorophyllide Oxidoreductase: Phylogeny, Regulation, and Catalytic Properties
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Phosphorylation‐mediated regulation of heat shock response in Escherichia coli
PublikacjaEscherichia coli has two heat shock regulons under the transcriptional control of Esigma(32) and Esigma(E) RNA polymerases. These polymerases control the expression of genes, the products of which are needed for correct folding of proteins in the cytoplasm and the extracytoplasm respectively. In this study, we report that mutations in a tyrosine phosphatase-encoding gene led to decreased activity of these heat shock regulons. The...
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Examining Impact of Speed Recommendation Algorithm Operating in Autonomous Road Signs on Minimum Distance between Vehicles
PublikacjaAn approach to a new kind of recommendation system design that suggests safe speed on the road is presented. Real data obtained on roads were used for the simulations. As part of a project related to autonomous road sign development, a number of measurements were carried out on both local roads and expressways. A speed recommendation model was created based on gathered traffic data employing the traffic simulator. Depending on...
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A Comparative Study of Fuzzy SMC with Adaptive Fuzzy PID for Sensorless Speed Control of Six-Phase Induction Motor
PublikacjaMulti-phase motors have recently replaced three-phase induction motors in a variety of applications due to the numerous benefits they provide, and the absence of speed sensors promotes induction motors with variable speed drives. Sensorless speed control minimizes unnecessary speed encoder cost, reduces maintenance, and improves the motor drive’s reliability. The performance comparison of the fuzzy sliding mode controller (FSMC)...
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A Comparative Study of Fuzzy SMC with Adaptive Fuzzy PID for Sensorless Speed Control of Six-Phase Induction Motor
PublikacjaMulti-phase motors have recently replaced three-phase induction motors in a variety of applications due to the numerous benefits they provide, and the absence of speed sensors promotes induction motors with variable speed drives. Sensorless speed control minimizes unnecessary speed encoder cost, reduces maintenance, and improves the motor drive’s reliability. The performance comparison of the fuzzy sliding mode controller (FSMC)...
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Genetic Algorithm Approach for Gains Selection of Induction Machine Extended Speed Observer
PublikacjaThe subject of this paper is gains selection of an extended induction machine speed observer. A high number of gains makes manual gains selection difficult and due to nonlinear equations of the observer, well-known methods of gains selection for linear systems cannot be applied. A method based on genetic algorithms has been proposed instead. Such an approach requires multiple fitness function calls; therefore, using a quality index...
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Analysis of Failures of High Speed Shaft Bearing System in a Wind Turbine
PublikacjaDuring the operation of wind turbines with gearbox of traditional configuration, consisting of one planetary stage and two helical stages high failure rate of high speed shaft bearings is observed. Such a high failures frequency is not reflected in the results of standard calculations of bearing durability. Most probably it can be attributed to atypical failure mechanism. The authors studied problems in 1.5 MW wind turbines of...
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Immunity of residual current devices to the impulse leakage current in circuits with variable speed drives
PublikacjaThis paper concerns reliability of supply in variable speed drive circuits with residual current devices. During normal operation of these circuits high value of leakage current causes unwanted tripping of residual current devices. Immunity of residual current devices to the impulse leakage current should be evaluated. The system for testing of residual current devices and results of the test are presented
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Bifurcation of equilibrium forms of a gas column rotating with constant speed around its axis of symmetry
PublikacjaWe will be concerned with the problem of deformation of the lateral surface of a column that rotates with constant speed around its axis of symmetry. The column is filled by a gas and our goal is to investigate the deformation of the lateral surface depending on the pressure of the gas.
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Research and Analysis of High-Speed Data Transmission Radio Link Designed for Maritime Environment
PublikacjaIn these article, the realization of digital radio link for high-speed data transmission was presented. Its concept and practical realization, using USRP devices from National Instruments, were described. Developed software for generation and reception of digital signals in baseband, including description of modulation types, and time and frequency synchronization mechanisms, was presented. Moreover, an operation of designed radio...
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Research and analysis of high-speed data transmission radio link designed for maritime environment
PublikacjaIn these article the realization of digital radio link for high-speed data transmission was presented. Its concept and practical realization, using USRP devices from National Instruments, were described. Developed software for generation and reception of digital signals in baseband, including description of modulation types, and time and frequency synchronization mechanisms, was presented. Moreover, an operation of designed radio...
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Running characteristics of aerodynamic bearing with self-lifting capability at low rotational speed
PublikacjaAn aerodynamic journal bearing that is capable of self-generating squeeze-film pressure is presented and its dynamic characteristics investigated numerically and experimentally. A numerical method based on a time marching static model was applied to assess the orbit trajectory path of the rotor upon a perturbation. Experimental results were obtained to validate the effect of the self- generated squeeze-film pressure on the stability...
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Sensorless Control of Induction Motor Based on Super-Twisting Sliding Mode Observer With Speed Convergence Improvement
PublikacjaThe super twisting sliding-mode observer (ST-SMO) has been proposed to achieve an effective method for alleviating low-order harmonics of measured quantities, issues related to DC drift, and suppression of chattering due to low-frequency sampling. The conventional ST-SMO, on the other hand, suffers from control delay in the convergence trajectory due to the system disturbance, resulting in decreased anti-disturbance capability...
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Variable speed small hydropower plant
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Optimisation of inland vessels' route speed.
PublikacjaW pracy przedstawiono rezultaty badań dotyczących metody doboru prędkości i oceny zapotrzebowanej mocy napędu statków śródlądowych, przydatnej zarówno we wstępnych etapach projektowania, jak i w zarządzaniu eksploatacją taboru śródlądowego, np. przy ustalaniu harmonogramu rejsów pasażerskich statków wycieczkowych. Do rozwiązania problemu zastosowano metodę optymalizacji nieliniowej z ograniczeniami, opartą na minimalizacji kosztu...
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A mobile loop order–disorder transition modulates the speed of chaperonin cycling
PublikacjaMolecular machines order and disorder polypeptides as they form and dissolve large intermolecular interfaces, but the biological significance of coupled ordering and binding has been established in few, if any, macromolecular systems. The ordering and binding of GroES co-chaperonin mobile loops accompany an ATP-dependent conformational change in the GroEL chaperonin that promotes client protein folding. Following ATP hydrolysis,...
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Experimental Study of Flow Rate in Hydraulic Satellite Motor with the Rotating Case at a Low Constant Rotational Speed
PublikacjaIn this article was described the methodology for the experimental study of flows in the prototype of a satellite hydraulic motor with a rotating body. The experimental tests of the motor were carried out at a low constant rotational speed in a wide range of pressure drop in this motor. The constant rotational speed of the motor was kept by a worm gear. Based on the test results, the leakage characteristics in the flat gaps of...
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Speed sensorless ac drive with inverter output filter and fault detection using load torque signal
PublikacjaIn this paper, a sensorless induction motor (IM) drive using speed observer system is presented. The system includes load torque computation for gear fault detection. Nonlinear control method is adopted for controlling the motor over a wide speed range. An LC filter for smoothing current and voltage waveforms is used at the output of the voltage inverter. The use of filter imposes more building of the used observer to avoid using...
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Centrally Pivoted Tilting Pad Thrust Bearing with Carbon-Based Coated Collar—Experimental Results of Low- and Medium-Speed Operation
PublikacjaExperimental results of the research on a tilting pad thrust bearing with symmetrical pad support in the conditions of high loads and low speeds are presented in the paper. As described in the literature review, experimental results of tilting pad bearings at low speed/high load regime and transient conditions are rare. Unusual material selection - steel pad against a DLC-type coating on the collar was utilized. Such material combination...
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Lactose and β-Glucosides Metabolism and Its Regulation in Lactococcus lactis: A Review
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Rat cathepsin K: Enzymatic specificity and regulation of its collagenolytic activity
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Regulation of replication of λ phage and λ plasmid DNAs at low temperature
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Regulation of the switch from early to late bacteriophage λ DNA replication
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Renal Regulation of Calcium-Phosphate Metabolism in Single- and Twin Pregnant Goats
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Regulation of Cellular Redox Homeostasis by (–)-Epicatechin and Cocoa Extracts—A Pilot Study
PublikacjaCocoa polyphenols play an important role in protection against diseases in which oxidative stress is implicated as a causal or contributing factor. The main aim of this study was to elucidate the influence of different cocoa extracts and main cocoa bioactive compound (–)-epicatechin on cell growth and support of antioxidant cellular barrier in colon adenocarcinoma cell line model (HT29). Results show that the tested cocoa bioactivity...
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REGULATION OF CELLULAR REDOX HOMEOSTASIS BY (-)-EPICATECHIN AND COCOA EXTRACTS – PILOT STUDY
PublikacjaCocoa polyphenols play an important role in protection against diseases in which oxidative stress is implicated as a causal or contributing factor. The main aim of this study was to elucidate the influence of different cocoa extracts and main cocoa bioactive compound (–)-epicatechin on cell growth and support of antioxidant cellular barrier in colon adenocarcinoma cell line model (HT29). Results show that the tested cocoa bioactivity...
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A new factor LapD is required for the regulation of LpxC amounts and lipopolysaccharide trafficking
PublikacjaLipopolysaccharide (LPS) constitutes the major component of the outer membrane and is essential for bacteria, such as Escherichia coli. Recent work has revealed the essential roles of LapB and LapC proteins in regulating LPS amounts; although, if any additional partners are involved is unknown. Examination of proteins co-purifying with LapB identified LapD as a new partner. The purification of LapD reveals that it forms a complex...
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Implementation of high-speed data transmission technological demonstrator using software defined radio technology
PublikacjaIn the article implementation of high-speed data transmission technological demonstrator using software defined radio technology is presented. A system architecture design including asymmetric framing transmission organization, which differs from the ones used in cellular systems is described. The construction of technological demonstrator consisting of management unit, radio unit and programmable multithreaded software performing...
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Suppression of distortions in signals received from Doppler sensor for vehicle speed measurement
PublikacjaDoppler sensors are commonly used for movement detection and speed measurement. However, electromagnetic interference and imperfections in sensor construction result in degradation of the signal to noise ratio. As a result, detection of signals reflected from moving objects becomes problematic. The paper proposes an algorithm for reduction of distortions and noise in the signal received from a simple, dual-channel type of a Doppler...
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Accuracy, Memory and Speed Strategies in GPU-based Finite-Element Matrix-Generation
PublikacjaThis paper presents strategies on how to optimize GPU-based finite-element matrix-generation that occurs in the finite-element method (FEM) using higher order curvilinear elements. The goal of the optimization is to increase the speed of evaluation and assembly of large finite-element matrices on a single GPU (Graphics Processing Unit) while maintaining the accuracy of numerical integration at the desired level. For this reason,...
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Experimental study on the selected aspects of bow thruster generated flow field at ship zero-speed conditions
PublikacjaThe paper presents the results of experimental study on the interaction between the bow thrusters understood as the flow field changes generated by bow tunnel thruster in deep water conditions operated as a single and twin units. The research was limited to zero-speed case for the ship dead in the water. The influence of the hull form and jet spread between the neighbouring thrusters for several combinations of the applied bow...
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Implementation of high-speed data transmission technological demonstrator using software defined radio technology
PublikacjaIn the article implementation of a high-speed data transmission technological demonstrator using software defined radio technology is presented. A system architecture design including asymmetric framing transmission organization, which differs from the ones used in cellular systems is described. The construction of technological demonstrator consisting of a management unit, radio unit and programmable multi-threaded software performing...
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Novel adaptive flux observer for wide speed range sensorless control of induction motor
PublikacjaA new adaptive flux observer of induction motor is presented in the paper. The Lyapunov theory is utilized for derivation of the adaptation law of rotor flux angular speed, which acts as unknown parameter in an augmented induction motor model. In the field weakening region, where stray fluxes are comparable with rotor flux magnitude, the air-gap flux stabilization is proposed. An air-gap flux multiscalar model is derived for stator...
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Analysis of different tillage implements with respect to reduced fuel consumption, tractor operating speed and its wheel slippage
PublikacjaNowadays the prices of agricultural farm produced products are increasing with ant-speed and the prices of input for raising crops are increasing with rocket-speed. Therefore, there is a dire need to conduct some important studies to innovate the techniques which can lower the costs of crop production. In this context, this study was conducted to evaluate the consumption of fuel at different tillage implements, tractor operating...
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Influence of the Tool Rotational Speed on Physical and Chemical Properties of Dissimilar Friction-Stir-Welded AA5083/AA6060 Joints
PublikacjaAluminum alloys have been successfully used in the railroad and automotive industries because of their potential to significantly reduce component weights, and their good mechanical and anti-corrosion properties. Problems with joining aluminum alloys are characterized by low weldability, which influences the need for studies focused on unconventional methods. The environmentally friendly and low-cost friction-stir-welding method...
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Metrological analysis of an computerized system of protection against electric shock in circuits with variable speed drives
PublikacjaDrive systems, that can be operated at variable speed, are equipped with power electronics converters. This causes distortion of the earth current, and consequently the need to take into account the use of proper protective devices in relation to earth current harmonics. This paper presents a system for protection against electric shock in circuits with power electronics converters and metrological analysis indicating the requirements...
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Adaptive traffic optimization using Variable Speed Limits; Adaptacyjna optymalizacja ruchu drogowego przy pomocy zmiennych ograniczeń prędkości
PublikacjaVariable speed limits (VSL) is an intelligent transportation system (ITS) solution for traffic management. The speed limits can be changed dynamically in order to adapt to traffic, weather, or road surface conditions. This paper presents an approach for such an adaptive traffic control where the primary goal is to ensure traffic safety and efficiency of the traffic control system (fast response to dynamically changing traffic,...
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Effect of pine impregnation and feed speed on sound level and cutting power in wood sawing
PublikacjaThe sound levels along with the cutting power registered during the sawing process of the impregnated and non-impregnated pine wood at two feed speeds are shown and compared in this paper. Statistically significant differences in the acoustic signals occurred at the lower feed rate. The differences became smaller with an increase in the feed speed. In contrast to the sound signal, the differences...
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Optimization of the spindle speed during milling of large-sized structures with the use of technique of Experiment-Aided Virtual Prototyping
PublikacjaIn the paper are presented considerations concerning vibration suppression problems during milling of large-sized workpieces with the use of innovative method of matching the spindle speed of cutting tool. It depends on repeatable change of the spindle speed value as soon as the optimal vibration state of the workpiece approaches. The values of dominant “peaks” in the frequency spectra and the Root Mean Square (RMS) values of time...
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Changes in the speed of ants as a result of aggressive interactions
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Digital structures for high-speed signal processing
PublikacjaThe work covers several issues of realization of digital structures for pipelined processing of real and complex signals with the use of binary arithmetic and residue arithmetic. Basic rules of performing operations in residue arithmetic are presented along with selected residue number systems for processing of complex signals and computation of convolution. Subsequently, methods of conversion of numbers from weighted systems to...
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Frequency characteristics of induction machine speed observers
PublikacjaWłaściwości napędu bezczujnikowego z silnikiem indukcyjnym zależą od struktury obserwatora prędkości. System ten wymaga starannej analizy w przypadku uszkodzenia maszyny, której celem jest odpowiedź na pytania: jak układ regulacji pracuje przy niesymetrii maszyny spowodowanej np. uszkodzeniem klatki wirnika oraz jak obserwator odtwarza pulsacje prędkości spowodowane niesymetrią maszyny. W artykule przedstawiono charakterystyki...