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wszystkich: 1040
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Wyniki wyszukiwania dla: SPEED
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Validation study on a new semi-empirical method for the prediction of added resistance in waves of arbitrary heading in analyzing ship speed trial results
PublikacjaThis paper describes an open and extensive validation study carried out by the Specialist Committee on Ships in Operation at Sea (SOS) of the International Towing Tank Conference (ITTC) on the newly developed SHOPERA-NTUA-NTU-MARIC (SNNM) wave-added resistance prediction method. The SNNM method aims at a simple, fast and transparent determination of the added resistance in regular waves of arbitrary encounter directions, even when...
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The influence of screw configuration and screw speed of co-rotating twin screw extruder on the properties of products obtained by thermomechanical reclaiming of ground tire rubber
PublikacjaThe results of our investigations on the process of continuous thermomechanical reclaiming of ground tire rubber (GTR) carried out using a twin screw extruder are presented.We used a co-rotating twin screw extruder with a special configuration of plasticizing unit, enabling generation of considerable shear forces. The influence of screw configuration and screw speed on breaking of chemical crosslink bonds contained in ground tire...
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A small-signal sound speed and parameter of non-linearity B/Ain a ternary mixture. Examples of calculations of mixture consisting of air, water and water vapor
PublikacjaZostało wyliczone zaburzenie entropii z dokładnością do członów nieliniowych rzędu drugiego. Jedyne założenie ograniczające, toże para wodna i powietrze są gazami doskonałymi. Ostatecznie,parametr nieliniowości i prędkość fali akustycznej przedstawione jako rodzinę krzywych, zależnych od trzech parametrów. Przedstawiono ilustrację tych zależności.
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Relationship among the Change of Direction Ability, Sprinting, Jumping Performance, Aerobic Power and Anaerobic Speed Reserve: A Cross-Sectional Study in Elite 3x3 Basketball Players
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The Influence of Stretch Rod Speed on the Relationship between Preblown Bottle Aesthetic Quality and Final Blown Bottle Thickness Profile in Stretch Blow Molding from Preform Process
PublikacjaFrom a mechanical point of view, the aesthetic quality of preblown PET bottles and thickness profile of final blown PET bottles manufactured in ISBM process are determined by mechanical and thermal response of blown preforms. From the microscopic point of view the biggest influence on the mechanical and thermal properties of PET bottles have orientation and crystallization processes. From a technological point of view, the aesthetic...
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Graphical presentation of the power of energy losses and power developed in the elements of hydrostatic drive and control system. Part I. Rotational hydraulic motor speed series throttling control systems
PublikacjaZaproponowano i uzasadniono wykres przedstawiający kierunek wzrostu strumienia mocy narastającej od wału lub tłoczyska silnika hydraulicznego do wału pomopy, mocy narastającej w wyniku wymuszania przez moce strat energetycznych występujących w elementach układu i sterowania hydrostatycznego. Przedstawiono interpretację graficzną mocy strat energetycznych występujących w elementach układów, a także mocy rozwijanych przez te elementy....
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Graphical presentation of the power of energy losses and power developed in the elements hydrostatic drive and control system. Part II. Rotational hydraulic motor speed parallel throtling control and volumetric control systems
PublikacjaPrzedstawiono interpretację graficzną mocy strat energetycznych występujących w elementach układów napędu i sterowania hydrostatycznego, a także mocy rozwijanych przez te elementy. Dokonano analizy układu indywidualnego ze sterowaniem dławieniowym równoległym prędkości silnika hydraulicznego obrotowego, układu indywidualnego ze sterowaniem objętościowym, pompą o zmiennej wydajności, prędkości silnika hydrailicznego obrotowego,...
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Speed, alcohol and safety belts as important factors influencing the number voivodship = Prędkość, alkohol i pasy bezpieczeństwa jako istotne czynniki wpływające na liczbę ofiar śmiertelnych wypadków drogowych na obszarze województw
PublikacjaNiniejszy referat prezentuje wyniki wstępne szerszego programu prac badawczych dotyczących bezpieczeństwa ruchu drogowego na obszarach województw.
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Determination of pesticides in water using new solid phase extraction technique - speedisk and speedisk column.
PublikacjaW publikacji opisano zastosowanie nowych narzędzi do ekstrakcji do fazy stałej: szybkie dyski i szybkie kolumienki (speedisk i speedisk column). Zaprezentowano ich zastosowanie do ekstrakcji pestycydów z próbek wody, przy zastosowaniu różnych rozpuszczalników.
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The Speedup Analysis in GEM Detector Based Acquisition System Algorithms with CPU and PCIe Cards
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Determination of optimal rotational speeds of circular saws
PublikacjaW pracy przedstawiono możliwości diagnostyczne stanowiska HewSaw do badania zachowania się pił w funkcji prędkości obrotowej piły. Wykazano, ze wyznaczone wartości prędkości optymalnych badanych pił leżą poniżej wartości zalecanych przez producenta. Praca z prędkościami wyższymi od optymalnych może prowadzić do zwiększenia strat materiałowych, a także stwarzać zagrożenia dla obsługi.
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Chatter surveillance with the creation of a map of optimal spindle speeds
PublikacjaW pracy przedstawiono metodę nadzorowania drgań samowzbudnych typu chatter. Wyznaczono wartości optymalnych prędkości obrotowych wrzeciona dla poszczególnych punktów na powierzchni przedmiotu obrabianego, wykorzystując rożne techniki analizy modalnej. Badania eksperymentalne wykazały, że otrzymana w ten sposób mapa optymalnych prędkości obrotowych wrzeciona jest skutecznym narzędziem do eliminacji drgań chatter w procesie obróbki...
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The effect of a belt position in the spindle driving system on critical rotational speeds
PublikacjaThe aim of this paper was to examine how the belt pulley position affects critical rotational speeds of the modernized spindle of the sliding table saw Fx3. Methodology of determination of critical rotational speeds of the spindle in a function of the spindle design features and its driving system is presented. Spindles in these kind of machine tools are mainly driven with V-belts, and the pulleys on the spindles might be positioned:...
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Simplified Map-based Selection of Optimal Spindle Speeds When Milling Complex Structures
PublikacjaIn the paper a method for selecting optimal spindle speeds for complex structures during milling operations is presented. It is based on the selection of the spindle speed in accordance with a simple equation resulting from the minimisation of vibration energy, which leads to the minimisation of the work of cut-ting forces presented in previous elaborations by the authors [1]. Optimal spindle speeds are obtained for many points...
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Modelling of laminated glass PVB walls of buildings exposed to vehicle impact with different speeds
PublikacjaThis paper presents an analytical model, developed for laminated glass subjected to a low-velocity impact. It has the ability to capture glass cracks as well as large non-linear deformations. It is based mathematically on the firstorder deformation concept, which considers the effect of membrane and transverse shear as well as bending. This theory uses damage mechanics to capture the glass cracking. For this purpose, several experiments...
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Limitations of the Chladni patterns method for determination of circular saw blade critical rotational speeds
PublikacjaW pracy przedstawiono wyniki badań eksperymentalnych pił tarczowych z zastosowaniem figur Chladniego do wyznaczania obrotowych prędkości krytycznych pił tarczowych. Otrzymane wyniki wykazały, że w przypadku pił tarczowych o bardziej skomplikowanej budowie z długimi szczelinami, figury Chaldniego opisują postaci drgań, definiują częstotliwości rezonansowe. Jednakże, nie są one przydatne do wyznaczania obrotowych prędkości krytycznych...
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Analysis of turnouts with non-linear curvature of diverging track for different train running speeds
PublikacjaThe paper deals with the issue of shaping a variable curvature in the diverging track of the railway turnout. Solution without a circular arc in the central zone, comprising two zones of non-linear curvature, of the same length, having zero curvature values at the end points, was adopted as a model, on the basis of the previously conducted dynamic tests. Optimum type of curvature was selected from the point of view of the kinematic...
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Determination of the minimal critical rotational speeds of the circular saw blades with the quasi-twin resonant frequencies
PublikacjaTo determine the minimal critical rotational speeds of the circular saw blades is the fundamental aspect of obtaining the range of the rotational operating speeds, by which the circular saw blade can work with required stability. While for the circular saw blades with full-homogeneous bodies the determination of such rotational speeds is the relatively low level of difficulty function, whereas for circular saw blades with more...
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Analyses of the effect of the design features of the spindle of the sliding table saw upon its critical rotational speeds
PublikacjaProducenci pilarek formatowych do drewna dążą do zwiększania dokładności przecinania. Można to osiągnąć np. przez poprawę zachowania się wrzeciona, gdyż od niego w dużej mierze zależą efekty przecinania. Przedstawiono metodykę wyznaczania prędkości krytycznych wrzeciona pilarki formatowej w funkcji cech konstrukcyjnych wrzeciona i jego napędu.
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The Experimental Determination of Bearings Dynamic Coefficients in a Wide Range of Rotational Speeds, Taking into Account the Resonance and Hydrodynamic Instability
PublikacjaMethods for the experimental determination of dynamic coefficients are commonly used for the analysis of various types of bearings, including hydrodynamic, aerodynamic and foil bearings. There are currently several algorithms that allow estimating bearing dynamic coefficients. Such algorithms usually use various excitation techniques applied to rotor–bearings systems. So far only a small number of scientific publications show how...
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Determination of pharmaceutical residues in drinking water in Poland using a new SPE-GC-MS(SIM) method based on Speedisk extraction disks and DIMETRIS derivatization
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Investigating the Impact of Weather Conditions and Time of Day on Traffic Flow Characteristics
PublikacjaAdverse weather such as rain, snow, and fog may significantly reduce visibility or change adhesion properties and, as a consequence, affect drivers’ sense of safety, driving comfort, and their reaction to a changing driving environment (i.e., lower speed and increased headways). The changed behavior of individual drivers affects both traffic flow characteristics, that is, average speed and headways, and parameters related to highway...
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Resonant and nonresonant excitation of waves in a planar magnetosonic flow
PublikacjaForced propagation of perturbations in a magnetosonic wave are considered. The driving force may be caused by stimulated Mandelstam–Brillouin scattering of optic waves or by intense magnetosonic exciter. Some heating-cooling function which takes into account radiative cooling and unspecified heating is taken into consideration, as well as nonlinearity of a medium. Both these factors make the excitation particular. The analytical...
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Five-phase induction motor drive with sine-wave filter
PublikacjaThe paper presents closed loop ac drive with 5 phase induction motor operating with voltage source inverter and sine wave filter. The motor supply voltages and currents have sinusoidal shape. For well known adjustable electric drives the field oriented control method with flux and speed co ntrol can be applied. In the presence of output filter both control and estimation algorithms should be modified due to sine wave filter installation....
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DYNAMIC ANALYSIS OF HISTORIC RAILWAY BRIDGES IN POLAND IN THE CONTEXT OF ADJUSTING THEM TO PENDOLINO TRAINS
PublikacjaThe article presents the dynamic analysis of the historic railway bridge in Tczew as an example of the usefulness of such type of bridge for high-speed trains. The model of the bridge and the simulation of rolling stock passage was performed in SOFISTIK program. The scope of work includes experimental studies, the solution of the problem concerning the correct solution features dynamic model takes into account the dependencies...
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MACHINE VISION DETECTION OF THE CIRCULAR SAW VIBRATIONS
PublikacjaDynamical properties of rotating circular saw blades are crucial for both production quality and personnel safety. This paper presents a novel method for monitoring circular saw vibrations and deviations. A machine vision system uses a camera and a laser line projected on the saw’s surface to estimate vibration range. Changes of the dynamic behaviour of the saw were measured as a function of the rotational speed. The critical rotational...
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Trajectory planning for Service Ship during emergency STS transfer operation
PublikacjaIn this paper trajectory for approaching during emergency STS transfer operation with oil spill is considered as a sequence of navigation manoeuvres in specific navigational environment. The designed way points - ship positions and speed are determined as reference values to support navigator in decision making during steering and to mitigate the risk of collision which mostly results from exceeding the speed limit of approaching....
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Towards Universal Visualisation of Emotional States for Information Systems
PublikacjaThe paper concerns affective information systems that represent and visualize human emotional states. The goal of the study was to find typical representations of discrete and dimensional emotion models in terms of color, size, speed, shape, and animation type. A total of 419 participants were asked about their preferences for emotion visualization. We found that color, speed, and size correlated with selected discrete emotion...
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Combined thrust radial bearing of a submarine main shaft – Design and analysis of failure
PublikacjaThis paper presents an analysis of the combined thrust radial bearing of a submarine propulsion shaft. The lubrication system of the bearing is based on a fixed ring. The efficiency of the lubrication system depends on the shaft speed and temperature, which affects oil viscosity. In turn, the thrust bearing load also depends on the rotational speed of the shaft, because as the speed increases, the drag of the ship increases simultaneously,...
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Theoretical and Actual Feed Per Tooth During Wood Sawing on an Optimizing Cross-Cut Saw
PublikacjaThe work presents the geometries of circular saw teeth, whose task is to divide the cross-cut of the cutting layer. For efficient machining on a cross-cut saw with high feed speed values (about 1 ms−1) maximal theoretical feeds per tooth are determined. These values were compared with the actual values determined during transverse cutting of pine wood on a special test stands in industrial conditions. In the experiment the rotational...
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Vibration Surveillance System with Variable Stiffness Holder for Milling Flexible Details
PublikacjaEfficient milling of the flexible details (i.e. rotor blades, thin-walled elements) using slender ball-end tools is a difficult task due to possibility of vibration occurrence. Because of the existence of certain conditions (small depths of cutting, regeneration phenomena), cutting process may lose stability and self-excited chatter vibration may appear. Frequency of the chatter vibration is close to dominant natural frequency...
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Running performance of an aerodynamic journal bearing with squeeze film effect
PublikacjaResults of theoretical and experimental studies concerning the performance of an aerodynamic journal bearing of which running is assisted by squeeze film ultrasonic levitation (SFUL) are presented in this paper. The SFUL mechanism not only can separate journal from the bearing at the start and stop phases of operation but also can significantly contribute to the dynamic stability of the bearing when it runs at speed. Computer calculations...
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Analysis of the Surface Stereometry of Alloyed Austenitic Steel after Fibre Laser Cutting using Confocal Microscopy
PublikacjaThe paper extends the concept of cut edge quality and examines the fibre laser cutting process. A Prima Power Platino Fiber Evo device with a reference speed (RS) of 3500 mm/min was used for laser cutting. In order to analyse the influence of the laser cutting speed on the cut edge quality of X5CrNi18-10 stainless steel sheets, macroscopic studies were conducted on a stereoscopic microscope and surface stereometry on a confocal...
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Multiscalar Control Based Airgap Flux Optimization of Induction Motor for Loss Minimization
PublikacjaBased on the induction motor model, considering the core loss resistance that accounts for magnetic characteristic saturation, a speed control approach is devised with an adaptive full-order (AFO) speed observer. The induction motor model analysis is done sincerely in a stationary reference frame. The control approach incorporates a flux reference generator designed to meet optimal operational circumstances and a nonlinear speed...
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THE MODELLING OF ACCUMULATION AND DISSIPATION OF ENERGY IN MECHANICAL DRIVE SYSTEM
PublikacjaThis paper presents a modelling of accumulation and dissipation energy in simple drive system. The simple drive system is presented by laboratory stand designed for calculate fatigue life of material for bending and rotation tests pieces. The laboratory stand was prepared to diagnosis of fatigue life of material by use energetic methods. This idea was submitted as utility model to Polish Patent Office. This laboratory stand gives...
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Underwater Navigation Ssystem Based on Doppler Shift – Measurements and Error Estimations
PublikacjaA new acoustic navigation system was developed to determine the position and speed of moving underwater objects such as divers and underwater vehicles. The path of an object and its speed were determined by the Doppler shifts of acoustic signals emitted by a transmitter placed on the object and received by four hydrophones installed at the periphery of the monitored body of water. The position and speed measurements were affected...
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Impact of adverse winter weather on traffic flow
PublikacjaThe paper aims to analyse the impact of adverse weather in winter on traffic flow using data from a dual carriageway section of an express road located in Gdansk. For the purposes of the analysis, traffic and meteorological data were collected for a period of 15 months in 2014-2015 and aggregated to 5 minutes intervals. The impact of winter weather conditions on traffic flow was assessed by comparing aggregated traffic stream parameters...
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Development of the New Polish Method for Capacity Analysis of Motorways and Expressways
PublikacjaThe paper presents development of the new Polish method for performing capacity analysis of basic segments of dual carriageway roads (motorways and expressways). The method is based on field traffic surveys conducted at 30 motorway and expressway sites (class A and S roads) in Poland. Traffic flows, composition and travel times were observed in 15-min intervals at each site using ANPR filming method. These data were used to calibrate...
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Assessment of Corrosive Behaviour and Microstructure Characterization of Hybrid Friction Stir Welded Martensitic Stainless Steel
PublikacjaThis study examined the effect of induction heating on the microstructure and corrosion characteristics of hybrid friction stir welded AISI 410 stainless steel. Five joints have been produced with different friction stir welding parameters like welding speed, spindle speed, plunge depth, and induction power. Their microstructures were evaluated using a scanning electron microscope, and chemical composition was examined using...
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A decision-making system supporting selection of commanded outputs for a ship's propulsion system with a controllable pitch propeller
PublikacjaThe ship's operators have to make decisions regarding the values of commanded outputs (commanded engine speed and pitch ratio) which ensure maximum vessel speed and minimum fuel consumption. Obviously, the presented decision problems are opposed. Therefore, there is a need for a compromise solution that enables more flexible vessel voyage planning. This paper deals with development of a computer-aided system supporting selection...
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Analysis of positioning error and its impact on high frequency properties of differential signal coupler
PublikacjaThis paper presents the analysis of the effect of differential signal coupler positioning accuracy on its high frequency performance parameters for contact-less high speed chip-to-chip data transmission on PCB application. Our considerations are continuation of the previous works on differential signal coupler concept, design methodology and analysis for high speed data transmission monitoring. The theoretical analysis of possible...
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Travel Time of Public Transport Vehicles Estimation
PublikacjaEffective prediction of speed is central to advanced traveler information and transportation management systems. The speed of public transport vehicles is affected by many external factors including traffic volume, organization and infrastructure. The literature presents methods for estimating travel time on sections of a transport network and vehicle arrival at stops, often making use of the AVL (automatic vehicle location). The...
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High Frequency Conducted Emission in AC Motor Drives Fed By Frequency Converters: Sources and Propagation Paths
PublikacjaProvides a concise and thorough reference for designing electrical and electronic systems that employ adjustable speed drives Electrical and electronic systems that employ adjustable speed drives are being increasingly used in present-day automation applications. They are considered by many application engineers as one of the most interfering components, especially in a contemporarily faced industrial environment. This book fills...
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Analysis of Positioning Error and Its Impact on High Frequency Performance Parameters of Differential Signal Coupler of Differential Signal Coupler
PublikacjaThis paper presents the analysis of the effect of differential signal coupler positioning accuracy on its high frequency performance parameters for contact-less high speed chip-to-chip data transmission on PCB application. Our considerations are continuation of the previous works on differential signal coupler concept, design methodology and analysis for high speed data transmission monitoring presented in [1, 2]. The theoretical...
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Sensorless IPMSM drive with rotor position estimator based on analysis of phase current derivatives
PublikacjaThis paper describes a sensorless Interior Permanent Magnet Synchronous Motor (IPMSM) drive designed for traction applications. Wide-speed sensorless operation is provided with the use of three methods of rotor position estimation designed for: a standstill, low- and high-speed range. The paper focuses on the high-speed estimation algorithm. The estimator uses the derivatives of motor phase currentsresulting from PWM modulation...
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Conditions for Multiple Acquisition of Echoes from Stationary Targets in Successive Transmissions of Active Sonars
PublikacjaIn echolocation, the highest possible number of contacts with a detected target is clearly decisive on the possibilities of echo processing to optimise the estimation of distinctive characteristics of the observed target. In hydrolocation, the slow propagation of acoustic waves in water reduces the number of contacts of echosounders and sonars with detected targets. The article considers model conditions for acquiring multiple...
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FAILURE OF MAGNETIC FLUID SEALS OPERATING IN WATER: PRELIMINARY CONCLUSIONS
PublikacjaThe article analyses properties of magnetic fluid seals installed in rotary sealing no des which operate in the utility water environment. Seals of this type have been examined as a possible solution to the problem with ship manoeuvring propulsion sealing. The present analysis bases on laboratory durability tests of magnetic fluid seals expo sed to long - term utility water loads, at different water pressures and shaft revolutions....
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Vessel Energy Requirement Prediction from Acceleration Stage Towing Tests on Scale Models
PublikacjaOne of the most crucial tasks for naval architects is computing the energy required to meet the ship’s operational needs. When predicting a ship’s energy requirements, a series of hull resistance tests on a scale model vessel is carried out in constant speed stages, while the acceleration stage measurements are ignored. Another important factor in seakeeping analysis is the ship’s hydrodynamic added mass. The second law of dynamics...
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The system for remote monitoring of a vertical axis wind farm
PublikacjaThe article presents a system for remote monitoring of working parameters of a wind turbine with a vertical axis. The monitoring system was built using a Raspberry PI 3 microcomputer with the Raspbian operating system and a MicroDAQ E2000 measuring card. The developed system enables monitoring the power output of the generator, torque on the turbine shaft, turbine speed and wind speed. The values of the monitored parameters are...
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Sensorless Rotor Position Estimation of Doubly-Fed Induction Generator Based on Backstepping Technique
PublikacjaThis paper proposes a speed observer algorithm for the sensorless control of a doubly-fed induction generator based on classical adaptive backstepping technique. The sensorless control is shown using classic stator field oriented control which is used to active and reactive power control. Performance of the proposed algorithm of a speed observer is validated by simulation and experimental results obtained using a small-rating generator...