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Search results for: WEATHER ROUTING MULTI-OBJECTIVE CONSTRAINED OPTIMIZATION SHIP SYNCHRONOUS ROLLING RESONANCE FREQUENCY OF ROLLING EQUIVALENT METACENTRIC HEIGHT NATURAL PERIOD OF SHIP ROLL
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Analysis of catalitic reactors usefulness to reduce pollution generated by piston combustion engines with regard to ship main engines
PublicationThe article presents results which indicate that the use of catalytic reactors to reduce emissions of harmful compunds contained in the exhaust gas is important in the operation of vehicle motors operation. Efforts of the shipbuilding industry to reduce the toxicity of exhaust gas emitted by the main engines have been indicated and pointed to the desirability of the use of these catalysts in maritime transport. It has been pointed...
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From the multiple frequency tracker to the multiple frequency smoother
PublicationThe problem of extraction/elimination of nonstationary sinusoidalsignals from noisy measurements is considered. This problem is usually solved using adaptive notch filtering (ANF)algorithms. It is shown that the accuracy of frequency estimates can be significantly increased if the results obtained from ANF are backward-time filtered by an appropriately designed lowpass filter. The resulting adaptive notch smoothing (ANS)algorithm...
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Reduced-cost optimization-based miniaturization of microwave passives by multi-resolution EM simulations for internet of things and space-limited applications
PublicationStringent performance specifications along with constraints imposed on physical dimensions, make the design of contemporary microwave components a truly onerous task. In recent years, the latter demand has been growing in importance, with the innovative application areas such as Internet of Things coming into play. The need to employ full-wave electromagnetic (EM) simu-lations for response evaluation, reliable yet CPU heavy, only...
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Reduced-cost constrained miniaturization of wideband antennas using improved trust-region gradient search with repair step
PublicationIn the letter, an improved algorithm for electromagnetic (EM)-driven size reduction of wideband antennas is proposed. Our methodology utilizes variable-fidelity EM simulation models, auxiliary polynomial regression surrogates, as well as multi-point response correction. The constraint handling is implicit, using penalty functions. The core optimization algorithm is a trust-region gradient search with a repair step added in order...
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Development of an emulation platform for synchronous machine power generation system using a nonlinear functional level model
PublicationThe article presents the Power Hardware in the Loop (PHIL) approach for an autonomous power system analysis based on the synchronous generator model incorporating magnetic saturation effects. The model was prepared in the MATLAB/Simulink environment and then compiled into the C language for the PHIL platform implementation. The 150 kVA bidirectional DC/AC commercial-grade converter was used to emulate the synchronous generator....
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Design optimization of novel compact circular polarization antenna
PublicationThe paper describes a structure and a design optimization procedure of a miniaturized circular polarization antenna with elliptical ground plane slots and feed line with stepped-impedance stubs. Constrained optimization of all antenna parameters is executed in order to explicitly reduce the antenna size while maintaining required impedance axial ratio bandwidth of 5 GHz to 7 GHz at the same time. The size of the optimized antenna...
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Multi-headed chimera states in coupled pendula
PublicationWe discuss the occurrence of the chimera states in the network of coupled, excited by the clock’s mechanisms pendula. We find the patterns of multi-headed chimera states in which pendula clustered in different heads behave differently (oscillate with different frequencies) and create different types of synchronous states (complete or phase synchronization). The mathematical model of the network shows that the observed chimera states...
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The OptD-multi method in LiDAR processing
PublicationNew and constantly developing technology for acquiring spatial data, such as LiDAR (light detection and ranging), is a source for large volume of data. However, such amount of data is not always needed for developing the most popular LiDAR products: digital terrain model (DTM) or digital surface model. Therefore, in many cases, the number of contained points are reduced in the pre-processing stage. The degree of reduction is determined...
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Determination of equivalent circuit parameters of an induction motor using field calculation software
PublicationSimulation of the drive system comprising a power electronic converter and an induction motor requires that the equivalent circuit parameters of the motor are known. These parameters can be either measured or calculated. A method of calculation of self and mutual inductances that are parameters of a polyphase model of the motor is presented in the paper. All self-inductances and mutual inductances have been calculated using the...
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Problems with microprocessor voltage-to-frequency and frequency-to-voltage converters implementation
PublicationThe article presents the problems of digital voltage-to-frequency and frequency-to-voltage processing. Transducer systems implemented in microprocessor technology are presented, the timing of signals and functioning algorithms are discussed. An analysis of processing errors has been performed and the results of experimental studies of realized systems are presented.
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Simulation of influence of the air gap asymmetryon voltage waveforms of a synchronous machine
PublicationResults of simulation of a synchronous generator with the air gap asymmetry characterised by eccentricity are presented in the paper. The Lagrange's energy method has been used in derivation of the model equations. Analysis of influence of the air gap asymmetry on characteristics of self and mutual inductances of windings, as well as analysis of induced voltage waveforms as a function of the air gap asymmetry have been performed....
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Multi-response optimization on the effect of wet and eco-friendly cryogenic turning of D2 steel using Taguchi-based grey relational analysis
PublicationMaterial removal processes, including turning and milling, are still commonly used operations for manufacturing most of mechanical components in modern industry. Apart from the cutting parameters, the cooling method has the great impact on the technological efects and, above all, on the environmental friendliness of production. In this study, multi-response optimization on the efect of wet and cryogenic machining is performed during...
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Minimization of a ship's magnetic signature under external field conditions using a multi-dipole model
PublicationThe paper addresses the innovative issue of minimizing the ship's magnetic signature under any external field conditions, i.e., for arbitrary values of ambient field modulus and magnetic inclination. Varying values of the external field, depending on the current geographical location, affect only the induced part of ship's magnetization. A practical problem in minimizing the ship signature is separating permanent magnetization...
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Improving Output Performance of the Ultrasonic Multicell Piezoelectric Motor by Development the Multi-Rotor Structure
PublicationIn recent years, many researches have been carried out on piezoelectric multi-rotor structures. This paper describes the analysis, development and experimental process of an ultrasonic multi-cell piezoelectric motor using a multi-rotor structure. In this design, three independent cells have been integrated into a mechatronic system. Analytical model and finite element method are used for modal and dynamic analysis of the proposed...
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Multi-fidelity aerodynamic design trade-off exploration using point-by-point Pareto set identification
PublicationAerodynamic design is inherently a multi-objective optimization (MOO) problem. Determining the best possible trade-offs between conflicting aerodynamic objectives can be computationally challenging when carried out directly at the level of high-fidelity computational fluid dynamics simulations. This paper presents a computationally cheap methodology for exploration of aerodynamic design trade-offs. In particular, point-by-point...
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Surrogate Modeling and Optimization Using Shape-Preserving Response Prediction: A Review
PublicationComputer simulation models are ubiquitous in modern engineering design. In many cases, they are the only way to evaluate a given design with sufficient fidelity. Unfortunately, an added computa-tional expense is associated with higher fidelity models. Moreover, the systems being considered are often highly nonlinear and may feature a large number of designable parameters. Therefore, it may be impractical to solve the design problem...
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Optimization issues in distributed computing systems design
PublicationIn recent years, we observe a growing interest focused on distributed computing systems. Both industry and academia require increasing computational power to process and analyze large amount of data, including significant areas like analysis of medical data, earthquake, or weather forecast. Since distributed computing systems – similar to computer networks – are vulnerable to failures, survivability mechanisms are indispensable...
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Lubricant property and rolling contact fatigue test of oil-in-water emulsion type HFA-E and oil Total Azolla 46 as working liquids in hydraulic systems
PublicationW artykule scharakteryzowano i opisano wyniki badań własności smarnych wody destylowanej, emulsji wodno-olejowej typu HFA-E (1% oleju w wodzie) sporządzonej na bazie koncentratu Isosynth VX110BF, oleju Total Azolla 46 i samego koncentratu Isosynth VX110BF (tylko dla porównania z olejem, emulsją i wodą). W artykule pokazano wyniki badań pittingu z użyciem wody, emulsji i oleju jako środków smarnych. Ponadto w artykule przedstawiono...
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Variations of Ship’s Deck Elevation Due to Stochastic Process of Containers Loading
PublicationThe stochastic process of container loading is described in the paper with special emphasis to ship motion when she is lying at a quay. The 3 DOF system was applied to describe rolling, pitching and heaving of a vessel which may cause a significant variations of momentary deck elevation. The realistic range of such variations are assessed for a variety of cargo locations on-board and a phase shift between two independent gantries...
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A model development and experimental verification for a vapour microturbine with a permanent magnet synchronous generator
PublicationVapour microturbines with permanent magnet synchronous generators are implemented in micropower plants for dispersed power generation systems. The dynamic model of such a microturbine set was developed and presented. The developed relations result from the generic equations. Experimental data for two different working medium were used for model verification. A microturbine set model was tested during the changes in the parameters...
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SPECTRAL-BASED MODAL PARAMETERS IDENTIFICATION WITH MULTIPLE PARTICLE SWARMS OPTIMIZATION
PublicationThe paper presents usage of a Particle Swarm Optimization [1] based algorithm for spectral-based modal parameters identification. The main algorithm consists of two groups of swarms, namely, scouts and helpers. For the first group additional penalizing process is provided to force separation of scouting swarms in frequency space. The swarms have an ability to communicate with each other. At first stage, each swarm focuses on a...
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Modelling and analysis of medium frequency transformers for power converters
PublicationThe evolutions in power systems and electric vehicles, related to the economic opportunities and the environmental issues, bring the need of high power galvanically isolated DC-DC converter. The medium frequency transformer (MFT) is one of its key components, enabled by the increasing switching frequency of modern power semiconductors like silicon carbide transistors or diodes. The increased operating frequency offers small...
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Computational model for simulation of lifeboat motions during its launching from ship in rough seas
PublicationW artykule przedstawiono model obliczeniowy 3 D, opisujący ruch obiektu w 6 stopniach swobody (6DoF), do symulacji ruchu jedno- lub dwuzawiesiowej łodzi ratunkowej lub ratowniczej podczas opuszczania ze statku na wzburzonej wodzie. Jest to złożony model uwzględniający warunki morskie oraz elastyczność i własności tłumiące elementów i mechanizmów żurawika, liny oraz kadłuba łodzi. Ponadto przedstawiono przykładowe wyniki obliczeń...
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An integrated hydraulic drive system of a novel device for launching lifeboats from large passenger ship
PublicationArtykuł przedstawia zintegrowany układ napędu i sterowania hydraulicznego systemu ewakuacyjnego składającego się z wyciągu łańcuchowego z zamocowanymi na nim łodziami ratunkowymi oraz furto-rampy rufowej. Zastosowana tu furto-rampa z elementem wypornościowym umożliwia zwiększenie jej funkcji do samoczynnego dostosowania kąta jej wychylenia roboczego w przypadku znacznego przegłębienia statku na dziób. Przedstawiony układ hydrauliczny...
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CAUSALITY IN MODELS OF THERMAL PROCESSES IN SHIP ENGINE ROOMS WITH THE USE OF BOND GRAPH (BG) METHOD
PublicationWith a single approach to modeling elements of different physical nature, the method of Bond Graph (BG) is particularly well suited for modeling energy systems consisting of mechanical, thermal, electrical and hydraulic elements that operate in the power system engine room. The paper refers to the earlier presented new concept of thermal process modeling using the BG method. The authors own suggestions for determining causality...
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Analysis and Experimental Verification of Improving the EEDI of a Ship using a Thruster Supplied by a Hybrid Power System
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On possible lowering fuel oil consumption by differentiating loads on ship diesel engines running in parrallel.
PublicationPodano możliwości zmniejszenia zużycia paliwa przez silniki okrętowe pracujące równolegle dzieki różnicowaniu ich obciążeń eksploatacyjnych. Zaprezentowano podstawy teoretyczne oraz sposób postępowania przy pomiarach zużycia paliwa w czasie rzeczywistym.
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Problem of optimal load distribution between generators minimizing risk of enegretic ship system overload.
PublicationOmówiono system rozdziału mocy czynnych pomiędzy generatorami w systemie energetycznym statku. Minimalizuje się ryzyko przeciążeń systemu przy jednoczesnej minimalizacji kosztów wytwarzania energii w systemie.
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The application of an expert system for simulation investigations in yhe aided design of ship power systems automation.
PublicationPrzedstawiono strukturę i funkcje systemu wspomagającego projektowanie automatyki systemów enegretycznych statków. Dane opisujące projektowany podsystem energetyczny są wprowadzane w trybie interaktywnym do systemu ekspertowego. Reguły określaja poprawność formalną i merytoryczną wprowadzonych danych. W przypadku braku błędów system automatycznie tworzy model symulacyjny projektowanego podsystemu enegretycznego i wywołuje program...
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A Method of Risk and Safety Assessment During the Ship Salvage Using the Hazard, Release and Consequence Analysis
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Conception of selecting reliability models for taking operating decisionsrelated to sea-going ship´s systems
PublicationPrzedstawiono możliwości podejmowania decyzji dotyczących sytuacji, gdy decydent dysponuje informacją aprioryczną o stanie technicznym urządzeń, na przykład uzyskaną z badań niezawodności urządzeń niezbędnych do wykonania zadania, wyrażoną w formie prawdopodobieństwa. Do opracowania modelu umożliwiającego podejmowanie takich decyzji eksploatacyjnych wykorzystano elementy bayesowskiej statystycznej teorii decyzji.
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A concept of pusher - barge coupling device of two-segment ship for inland waterways and coastal service
PublicationW artykule przedstawiono założenia projektowe i koncepcję rozwiązania konstrukcyjnego oraz napędu i sterowania urządzenia sprzęgającego pchacz i barkę dwusegmentowego statku śródlądowego i przybrzeżnego. Zaprezentowane urządzenie umożliwia zarówno sztywne połączenie, jak i wzajemne kontrolowane wychylanie obu segmentów względem siebie, co w znacznym stopni zwiększa manewrowość, a tym samym bezpieczeństwo żeglugi, zwłaszcza na wąskich...
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Design concepts of propulsion and steering system for hotel unit of two-segment inland waterways ship
PublicationW artykule przedstawiono założenia projektowe i dwa rozwiązania koncepcyjne napędu i sterowania barki hotelowej, stanowiącej część dwusegmentowego statku śródlądowego i przybrzeżnego. Obydwa rozwiązania oparto na zastosowaniu dziobowego śrubosteru małej mocy, ze śrubą stałą umieszczoną w dyszy obrotowej. W jednym z rozwiązań śruba napędzana jest silnikiem hydraulicznym, zaś w drugim - silnikiem elektrycznym. Mechanizm obrotu kolumny...
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The system combined of low-speed marine diesel engine and steam turbine in ship propulsion applications
PublicationPrzedstawiono koncepcje okrętowego układu kombinowanego silnik wolnoobrotowy tłokowy- turbina parowa, wykorzystującego ciepło zawarte w spalinach wylotowych.Porównano układ kombinowany dużej mocy dla dwóch silników tłokowych porównywalnych mocy z punktu widzenia termodynamicznego.
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Influence of cathodic-protection-induced hydrogenation on mechanical properties of two ship hull plate steels
PublicationPrzedstawiono wyniki próby rozciągania i udarowej Charpy V dla stali zwykłej wytrzymałości (kategorii A) i podwyższonej wytrzymałości (kat. AH32) zarówno w stanie dostawy jak i po nawodorowaniu (protektor Zn w słonej wodzie). Nawodorowanie obydwu stali zwiększyło nieco granicę plastyczności (Re) i wydłużenie (A), nie zmieniając (atal A) lub nieco zmniejszając przewężenie (Z). Wpływ nawodorowania na udarność był ewidentnie pozytywny...
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Assessment of operation of energy system of serial reliability structure on the example of ship main propulsion system
PublicationW artykule przedstawiono rozwinięcie znanej metody oceny działania systemu energetycznego, zastosowanej w odniesieniu do głównego układu napędowego statku. Według tej interpretacji działanie może być przedstawiane jako wielkość fizyczna. W tym aspekcie, na podstawie wybranego podsystemów funkcjonalnego statku, oceniono jej przydatność do opisu własności niezawodnościowych tego systemu. W analizie zastosowano teorię procesów Poissona,...
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Numerical Analysis of the Unsteady Propeller Performance in the Ship Wake Modified by Different Wake Improvement Devices
PublicationThe paper presents summary of numerical analysis of the unsteady propeller forces and induced pressure pulses generated by the selected real propeller of 7000 tons product tanker, operating in five different wakefields including four inflenced by the different wake improvement devices. The results of the analysis are partly compared with experimental data and univocal conclusions about the optimum wake improvement device are presented.
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A Fuzzy Event Tree Model for Accident Scenario Analysis of Ship Stuck in Ice in Arctic Waters
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RANS-based design optimization of dual-rotor wind turbines
PublicationPurpose An improvement in the energy efficiency of wind turbines can be achieved using dual rotors. Because of complex flow physics, the design of dual-rotor wind turbines (DRWTs) requires repetitive evaluations of computationally expensive partial differential equation (PDE) simulation models. Approaches for solving design optimization of DRWTs constrained by PDE simulations are investigated. The purpose of this study is to determine...
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Inverse Modeling and Optimization of CSRR-based Microwave Sensors for Industrial Applications
PublicationDesign optimization of multivariable resonators is a challenging topic in the area of microwave sensors for industrial applications. This paper proposes a novel methodology for rapid re-design and parameter tuning of complementary split-ring resonators (CSRRs). Our approach involves inverse surrogate models established using pre-optimized resonator data as well as analytical correction techniques to enable rapid adjustment of geometry...
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Lexicographic and weighting approach to multi-criteria portfolio optimization by mixed integer programming
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Resilience through multicast – An optimization model for multi-hop wireless sensor networks
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Improving evolutionary multi-objective optimisation using genders [Usprawnienie ewolucyjnej wielokryterialnej optymalizacji poprzez zastosowanie rodzajników]
PublicationW rozwiązywaniu wielkowymiarowych problemów wielokryterialnej optymalizacji za pomocą obliczeń ewolucyjnych (EMO) koncepcja dominacji w sensie Pareto nie jest efektywna. Dlatego w pracy rozważa się nowe podejście do rozwiązywania zadań wielokryterialnej optymalizacji metodą EMO, w którym wprowadza się pojęcie rodzajników genetycznych w celu rozróżnienia rozmaitych grup kryteriów oraz związanych z nimi subkryterialnych rozwiązań...
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Ultra-Compact Self-Quadruplexing Microfluidically Frequency Reconfigurable Slot Antenna Using Half-Mode SIW
PublicationIn this brief, the design of an ultra-compact self-quadruplexing frequency reconfigurable antenna (SQFRA) utilizing a half-mode substrate-integrated waveguide (HMSIW) and microfluidic channels is discussed. Four HMSIW cavities fed by four microstrip lines and slots are used to construct a highly compact antenna. The microstrip feedings to the HMSIW cavities are applied in such a way that the proposed antenna exhibits self-quadruplexing...
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Computer-aided analysis of resonance risk in power system with Static Var Compensators
PublicationStatic Var Compensators operation in a power system may significantly improve voltage profiles in nodes and the reactive power balance, as well as ensure greater system stability in emergency conditions. However these devices may be a cause of a resonance in the system. The aim of this paper is to call attention to the need to include resonance phenomena in a compensator’s location evaluation process. The analysis performed in...
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Productivity effects of trade in natural resources—comparison with mechanisms of technological specialisation
PublicationThis paper compares two alternative growth paths, assessing the effects on productivity of specialisation in natural resources (NR) and in technologically advanced products. The empirical analysis exploits product-level export data for 109 developing and 51 developed economies over the period 1996–2018. We document two distinct types of specialisation, based on exports either of natural resources or of technological products, and...
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Parametric optimization of sandwich composite footbridge with U-shaped cross-section
PublicationParametric optimization of sandwich composite footbridge was presented in the paper. Composite footbridge has 14,5 m long and has U-shaped cross-section with inner dimensions 2,6 × 1,3 m. The sandwich structure in made from GFRP laminate as a faces and PET foam as a core. The aim of analysis was to minimize the mass of the new footbridge that can lead to minimize the cost of structure. After optimization was conducted, the new...
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Polyarmonic model of synchronous generator for analysis of autonomous power generation systems
PublicationAbstract: This paper presents the polyharmonic modelling of synchronous generator (SG) in machine variables. The simple geometry and windings physical layout has been used for inductance calculations of a salient-pole SG. The main advantage of this model is the ease of describing an autonomous power generation system (APGS) in terms of its topology and thus providing effective analysis at the static and dynamic states, both for...
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Complex multidisciplinary optimization of turbine blading systems
PublicationThe paper describes the methods and results of direct optimization of turbine blading systems using a software package Opti_turb. The final shape of the blading is obtained from minimizing the objective function, which is the total energy loss of the stage, including the leaving energy. The current values of the objective function are found from 3D RANS computations (from a code FlowER) of geometries changed during the process...
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Routing Method for Interplanetary Satellite Communication in IoT Networks Based on IPv6
PublicationThe matter of interplanetary network (IPN) connection is a complex and sophisticated topic. Space missions are aimed inter alia at studying the outer planets of our solar system. Data transmission itself, as well as receiving data from satellites located on the borders of the solar system, was only possible thanks to the use of powerful deep space network (DSN) receivers, located in various places on the surface of the Earth. In...