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Search results for: DIELECTRIC WAVEGUIDES
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Structure and thermoelectric properties of bismuth telluride—Carbon composites
PublicationCarbon nanotubes and amorphous carbon have been introduced into a bismuth telluride matrix (0.15 and 0.30 wt.% ratio) to investigate the influence of the carbon on the composite’s thermoelectric properties. Composites with well-dispersed additives have been obtained by sonication and ball-milling methodology. Carbon nanotubes and an amorphous carbon addition led to a decrease in electric conductivity from 1120 S/cm to 77 S/cm....
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Secondary arc modelling for single pole reclosing analyses
PublicationThe paper discusses two evaluation methods of single pole auto-reclosing process effectiveness in HV transmission lines. Secondary arc current and recovery voltage calculation results obtained by load flow calculation are compared to the results obtained by the time domain simulations. Moreover, a nonlinear secondary arc model implementation is presented. The paper presents the study results for the three types of EHV transmission...
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Impact of configuration of earth continuity conductor on induced sheath voltages in power cables
PublicationIn high voltage power cable systems a problem of induced sheath voltages exist. Due to these voltages electric shock and damage of non-metallic outer sheath of the cables may occur. Exposure to voltage of the outer sheath may be very high in case of earth fault with high value of earth current. In order to reduce induced sheath voltages an earth continuity conductor (conductors) along power cables is applied. Configuration of this...
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Analysis of measurement uncertainty for contact-less method used to measure the position of catenary contact wire, performed with the use of Monte Carlo method
PublicationCurrently the majority of main railway lines in Europe are electrified, and electric trains have the biggest share in the entire amount of rail transport. Reliability of electrified railways is closely related to the issue of supplying traction vehicles with energy. The problems connected with diagnostics of energy consumption node, namely the contact line and the current collector, are therefore of fundamental importance for maintaining...
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Firing map of an almost periodic input function
PublicationIn mathematical biology and the theory of electric networks the firing map of an integrate-and-fire system is a notion of importance. In order to prove useful properties of this map authors of previous papers assumed that the stimulus function f of the system ẋ = f(t,x) is continuous and usually periodic in the time variable. In this work we show that the required properties of the firing map for the simplified model ẋ = f(t) still...
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Nonlinear Impedance as Possible Result of Ion-Polaron Interaction in Cu2O-Al2O3-SiO2 Glass
PublicationNonlinear a.c. impedance measurements were performed in Cu2O-Al2O3-SiO2 glass in wide frequency range. The obtained results shows that a large nonlinearity in the impedance signal is observed at moderate electric fields of an order 1V/mm. The contents of the third harmonics reaches about 10% and strongly depends on temperature and frequency. The investigated glass exhibits mixed electronic-ionic conductivity. Electronic conduction...
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A correlation between electron-hole pair radii and magnetomodulation of exciplex fluorescence in electron donor-electron acceptor organic systems
PublicationElectric field dependencies of electromodulated photoluminescence and magnitudes of the magnetic-field effect on photoluminescence havebeen measured in vacuum-evaporated films of m-MTDATA [4,4',4"-tris(N-(3-methylphenyl)-N-phenylamino)triphenylamine]:bathophe-nanthroline, m-MTDATA:BCP (bathocuproine), as well as 4,4',4"-tris[2-naphthyl(phenyl)amino]triphenylamine:BCP. The Sano-Tachiya-Noolandi-Hong extension of standard Onsager...
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The Influence of Cooperation on the Operation of an MPC Controller Pair in a Nuclear Power Plant Turbine Generator Set
PublicationThe paper discusses the problem of cooperation between multiple model predictive control (MPC) systems. This approach aims at improving the control quality in electrical energy generation and forms the next step in a series of publications by the authors focusing on the optimization and control of electric power systems. Cooperation and cooperative object concepts in relation to a multi MPC system are defined and a cooperative control...
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The influence of azide and imidazole on the properties of Mn- and Cd-based networks: conductivity and nonlinear phenomena
PublicationWe report a study on a family of four new Mn- and Cd-azide-imidazolate-based compounds with various crystal architectures. Notably, three of these compounds display noncentrosymmetric crystal arrangements at room temperature, a rare phenomenon in hybrid organic–inorganic materials. Both nonlinear optical (NLO) and electrical phenomena in these compounds are observed. The NLO processes include second and third harmonic generation,...
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A Comparative Study of Fuzzy SMC with Adaptive Fuzzy PID for Sensorless Speed Control of Six-Phase Induction Motor
PublicationMulti-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
PublicationMulti-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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Wielopoziomowe przekształtniki średniego napięcia (SN) o budowie modułowej
PublicationW artykule omówiono wybrane zagadnienia dotyczące zastosowań wielopoziomowych przekształtników średniego napięcia (SN) w układach napędowych o regulowanej prędkości, zwłaszcza w układach z izolacją od sieci zasilającej. W opracowanym przekształtniku zastosowano izolację galwaniczną od sieci zrealizowaną za pomocą izolowanych przetwornic dc-dc z transformatorami wysokiej częstotliwości (> 5 kHz). Przedstawiono zarejestrowane przebiegi...
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Marcin Gulczyński
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Przedwojenne wydawnictwa Stowarzyszenia Elektryków Polskich w bibliotekach i bibliotekach cyfrowych
PublicationArtykuł przedstawia krótką historię piśmiennictwa z dziedziny elektrotechniki. Po 1918 r. obserwuje się wzrost liczby publikacji, a wraz z rozwojem nauki zwiększa się obszar tematyczny literatury fachowej. Ogromną zasługę w tym rozwoju miało Stowarzyszenie Elektryków Polskich. W artykule pokazano sposoby wyszukiwania wydawnictw przedwojennych SEP, ich dostępność w bibliotekach, także cyfrowych. Przedstawia w jaki sposób zwiększyć...
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Advancing Urban Transit: Gepard and CAR projects - Innovations in Trolleybus Technology
PublicationThe Gepard project in Gdynia, Poland, revolutionized the city's trolleybus network with the introduction of “Trolleybus 2.0” vehicles and an innovative charging system. “Trolleybus 2.0” vehicles combine features of traditional trolleybuses and electric buses boasting traction batteries for autonomous driving and dual legal approval. Statistical analysis of energy consumption informed the development of a hybrid charging concept,...
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Silniki elektryczne w kosmonautyce
PublicationArtykuł jest pracą przeglądową dotyczącą silników elektrycznych (EP - Electric Propulsion)wykorzystywanych w kosmonautyce. Bardziej szczegółowo opisano działanie silnika elektrostatycznego działającego w oparciu o efekt Halla (HET - Hall Effect Thruster). Silnik ten jest powszechnie wykorzystywany w pozycjonowaniu satelitów, potencjalnie może być wykorzystany do dalekich misji planetarnych. HET jest obiektem wielu badań doświadczalnych...
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High-performance method of carbon nanotubes modification by microwave plasma for thin composite films preparation
PublicationIn this work we present a simple and efficient method of nitrogen plasma modification of carbon nanotubes (CNTs). The process allows for treatment of the nanotubes in the form of powder with quite a high yield (65 mg of CNTs per hour). The modified carbon nanotubes contain approx. 3.8% of nitrogen, mostly in the pyridinic form. Plasma treated CNTs exhibit better dispersibility in water and higher electric capacitance than pristine...
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Disturbances of Earth magnetic field caused by eddy currents of airplane
PublicationThe uniform magnetic field of the Earth in the surrounding of a mobile, metallic object undergoes deformation by eddy currents. The influence of the moving, conducting object on the Earth's total magnetic field depends on the object's shape, position and speed of the changes relative to the magnetic field vector of the Earth, as well as the electric conductivity and the relative magnetic permeability of the material. Disturbances...
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Nuclear power plant as a source of electrical energy and heat
PublicationIn this paper certain issues concerning usage of nuclear power plants as sources of not only electric power but also thermal energy will be discussed. For such a solution appeals most of all the need to limit harmful emissions of gases (including CO2) and ashes, which come from the process of burning fossil fuels, as well as the raising demand for network heat and chill. Additionally combined heat and power production brings measurable...
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Managing competence and certifying persons responsible for functional safety = Zarządzanie kompetencjami i certyfikacja osób odpowiedzialnych za bezpieczeństwo funkcjonalne
PublicationThis article emphasizes that knowledge and competences of managers, engineers and specialists dealing with safety-related technologies for hazardous industry should be appropriately shaped in the technical education processes and training programmes fulfilling some quality requirements and assessment criteria. It concerns especially persons dealing with the functional safety solutions in the design and operation of the electric,...
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Harmonic Vibrations of Nanosized Magnetoelectric Bodies with Coupled Surface and Interphase Effects: Mathematical Models and Finite Element Approaches
PublicationThe harmonic problems for piezomagnetoelectric nanosized bodies with taking into account the coupled damping and surface effects are considered on the base of the generalized Gurtin-Murdoch model. In the development of previous investigations, the coupled mechanical, electric and magnetic surface effects with surface inertial terms are introduced into the model. For a homogeneous model, the composite material is considered as homogeneous...
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Structure and optical parameters of Eu doped tellurium oxide thin films prepared by reactive magnetron sputtering method
PublicationIn this work the structural properties and photoluminescence of tellurium dioxide thin films doped by europium were described. Thin films were deposited by magnetron sputtering method and simultaneously heated at 200 °C. Presence of Eu ions and their valence states was confirmed by X-ray photoemission spectroscopy measurements. The structure of the films as well as the influence of europium dopant on crystalline structure of the...
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MIEJSKIE PROJEKTY OŚWIETLENIOWE W KONTEKŚCIE REWITALIZACJI
PublicationUrban Lighting in the Context of Regeneration Processes. The article presents how multi-layered urban lighting projects fi t into the programs of integrated activities to improve the living conditions of the local community, the surrounding space, and its economic relations. The role of the electric lighting in revealing the night image of the city, its promotion and public spaces transformations off ering new impressions to city...
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Kagome Lattice Promotes Chiral Spin Fluctuations
PublicationDynamical spin fluctuations in magnets can be endowed with a slight bent toward left- or right-handed chirality by Dzyaloshinskii-Moriya interactions. However, little is known about the crucial role of lattice geometry on these chiral spin fluctuations and on fluctuation-related transport anomalies driven by the quantum-mechanical (Berry) phase of conduction electrons. Via thermoelectric Nernst effect and electric Hall effect experiments,...
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Electronic conductivity in the SiO2-PbO-Fe2O3 glass containing magnetic nanostructures
PublicationThe linear impedance spectra of iron–silicate–lead glass samples were measured in the frequency range from 1 MHz to 1 MHz and in the temperature range from 153 K to 423 K. The structure was investigated by means of XRD and atomic force microscopy. Local electrical and magnetic properties of the samples were tested with the aid of electrostatic force microscopy (EFM) and magnetic force microscopy (MFM). The obtained results show...
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Electrical properties and structure of lead-borate glass containing iron ions.
PublicationThe ac and dc conductivity in iron–lead-borate glass samples was investigated in the frequency range from 1 mHz to 1 MHz and in the temperature range from 153 K to 423 K. The structure was investigated by the means of atomic force microscopy (AFM) and the crystalline phases (if present) were identified by the means of X-ray diffractometry. Two types of ac electrical behaviour were observed. The first group of glass samples which...
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High frequency impulse ground penetrating radar application in assessment of interlayer connections
PublicationGround Penetrating Radar (GPR) technique is commonly used in the nondestructive evaluation of pavement structures. In particular, this method is used to estimate thicknesses of pavement layers as well as it can be utilized in advanced studies of pavement structures. The device presented in this paper comprise the high frequency impulse antennas that allow for investigating the interlayer zones in terms of their electromagnetic...
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Rapid Design of 3D Reflectarray Antennas by Inverse Surrogate Modeling and Regularization
PublicationReflectarrays (RAs) exhibit important advantages over conventional antenna arrays, especially in terms of realizing pencil-beam patterns without the employment of the feeding networks. Unfortunately, microstrip RA implementations feature narrow bandwidths, and are severely affected by losses. A considerably improved performance can be achieved for RAs involving grounded dielectric layers, which are also easy to manufacture using...
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High gain/bandwidth off‑chip antenna loaded with metamaterial unit‑cell impedance matching circuit for sub‑terahertz near‑field electronic systems
PublicationAn innovative off-chip antenna (OCA) is presented that exhibits high gain and efficiency performance at the terahertz (THz) band and has a wide operational bandwidth. The proposed OCA is implemented on stacked silicon layers and consists of an open circuit meandering line. It is shown that by loading the antenna with an array of subwavelength circular dielectric slots and terminating it with a metamaterial unit cell, its impedance...
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Topography of iron-phosphate glasses doped with niobium and titanium tested by confocal microscope
Open Research DataThe topography of phosphate-iron glasses containing niobium and titanium were investigated with the use of confocal miscroscope. Glass samples of the composition of 35P2O5-30Fe2O3-35Nb2O5, 35P2O5-30Fe2O3-27.5Nb2O5-7.5TiO2 and 35P2O5-30Fe2O3-20Nb2O5-15TiO2 (in %mol) were prepared by the conventional melt quenching technique. Appropriate amounts of reagents...
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Experimental ultimate strength assessment of stiffened plates subjected to marine immersed corrosion
PublicationThis study experimentally analyses the impact of marine immersed corrosion degradation on the compressive strength of the stiffened plates where the lower degradation levels were considered. The corrosion degradation test was accelerated by controlling the natural corrosion environmental factors, avoiding applying an electric current. Different groups of corrosion degradation levels and initial plate thicknesses were investigated....
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Synchronized six-step voltage generation in high-speed PMSM drive
PublicationSynchronized voltage generation has already been considered in the context of pulse width modulation (PWM). References prove that synchronized PWM substantially decreases subharmonics in inverter output voltage when operating with low switching-to-fundamental frequency ratio. This paper identifies problems of unsynchronized voltage generation in electric drives under six-step inverter operation. Guidelines for the synchronization...
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USE OF LANGMUIR PROBE IN DIESEL ENGINE DIAGNOSTIC RESEARCH Part I MEASUREMENT TECHNOLOGY. - Part 1 : MEASUREMENT TECHNOLOGY
PublicationIn the paper, the basic assumptions of diesel engine cylinder system's diagnosing method, based on observation of emerging and moving electric charges of ionized gas in the combustion workspaces, using Langmuir's probe. In the first part of the paper, only the technology of the measurement and results of the preliminary diagnostic tests of laboratory engine Farymann Diesel D10 were presented. The primary purpose of the research...
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Multilevel model order reduction with generalized compression of boundaries for 3-d FEM electromagnetic analysis
PublicationThis paper presents a multilevel Model Order Reduction technique for a 3-D electromagnetic Finite Element Method analysis. The reduction process is carried out in a hierarchical way and involves several steps which are repeated at each level. This approach brings about versatility and allows one to efficiently analyze complex electromagnetic structures. In the proposed multilevel reduction the entire computational domain is covered...
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Implementation of daylight design strategies in urban planning - barriers to application in Poland
PublicationThis paper reflects on studies done in the area of daylight design methods with regard to principles that can be applied in architecture and urban planning strategies. The paper addresses barriers to the application of new daylight design methods in urban planning, and in particular discusses current Polish building regulations in the context of daylight design. The results of the pilot study carried out among 82 participants show...
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Computer System for Evaluation of Shock Hazard in Circuits with Non-sinusoidal Earth Currents
PublicationEffects of current on people are mainly considered for 50/60 Hz sinusoidal current and smooth direct current. However, modern low voltage circuits are very often equipped with power electronics converters – rectifiers, frequency converters, therefore non-sinusoidal earth currents (touch currents) occur. For non-sinusoidal currents safety criteria should be modified. This paper presents a computer system, based on LabVIEW environment,...
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Development of dynamic method for evaluation of inhibition efficiency on the example of 8-hydroxyquinolin
PublicationSelection of a proper inhibitor should be based on the evaluation of its mechanism and effective concentrations. Mechanism of inhibition usually has dynamic character due to changing physicochemical conditions of the environment and corroding metal surface. Most of actually used methods are stationary or contain assumptions which highly influences obtained values. Development of new dynamic method, based on modified EIS, allows...
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Możliwości zastosowania zasobnikowych jednostek trakcyjnych na liniach kolejowych na przykładzie Pomorskiej Kolei Metropolitalnej
PublicationW artykule zwrócono uwagę, że zasobniki stosowane głównie do rekuperacji energii, mogą być również wykorzystane do zasilania pociągów na niezelektryfikowanych i zelektryfikowanych odcinkach linii kolejowych. Innowacyjność tego rozwiązania wykazano na podstawie dwóch aplikacji kolejowych elektrycznych zasobnikowych jednostek trakcyjnych: pierwszej funkcjonującej od 2014 roku na linii Utsunomiya – Karasuyama w Japonii oraz drugiej,...
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Exfoliated graphite with spinel oxide as an effective hybrid electrocatalyst for water splitting
PublicationThe aim of the conducted research was to develop hybrid nanostructures formed from MnCo2O4 and exfoliated graphite. Carbon added during the synthesis allowed for obtaining a well-distributed MnCo2O4 particle size with exposed active sites contributing to the increased electric conductivity. The influence of the weight ratios of carbon to a catalyst for hydrogen and oxygen evolution reactions was investigated. The new bifunctional...
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Chestnut-Derived Activated Carbon as a Prospective Material for Energy Storage
PublicationIn this work, we present the preparation and characterization of biomass-derived activatedcarbon (AC) in view of its application as electrode material for electrochemical capacitors. Porouscarbons are prepared by pyrolysis of chestnut seeds and subsequent activation of the obtainedbiochar. We investigate here two activation methods, namely, physical by CO2and chemical usingKOH. Morphology, structure and specific surface area (SSA)...
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Optimization of using recuperative braking energy on a double-track railway line
PublicationIn the introduction, possible ways of reusing energy from recuperation are presented. Next, the paper investigates the possibility of using regenerative braking in the range allowed by the detailed timetable by adopting the method of transferring the recovered electric energy directly to the catenary and immediate use of this energy by another train at the same power section. In the main part of the work, it is shown, that the...
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Functional Safety Analysis including Human Factors
PublicationIn this paper selected aspects of human factors are discussed that should be taken into account during the design of safety-related functions for a complex hazardous installation and its protections. The layer of protection analysis (LOPA) methodology is used for simplified risk analysis based on defined accident scenarios. To control the risk the safety instrumented functions (SIFs) are identified and their safety integrity levels...
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Ultrasonic spectroscopy of silicon single crystal
PublicationSpecimens of Si single crystals with different crystal orientation [100] and [110] were studied by the electro-ultrasonic spectroscopy (EUS) and Resonant Ultrasonic Spectroscopy (RUS). A silicon single crystal is an anisotropic crystal, so its properties are different in different directions in the material relative to the crystal orientation. EUS is based on interaction of two signals: electric AC signal and ultrasonic signal,...
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Capillary pumped loop as a tool for collecting large heat fluxes from electronic devices on warships
PublicationThe combat potential of future warships will be directly related to the use of modern electronic devices being parts of advanced systems, such as, for instance, radar systems, fire aiming systems, fire detection systems, electric drive systems, and even electronic and radio-electronic weaponry, railguns and lasers, installed on these warships. The capacity and functionality of these devices is continually increasing, at decreasing...
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Low-frequency tripping characteristics of residual current devices
PublicationFast development of various types of converters makes their utilization in industry and in domestic installations very common. Due to converters, an earth fault current waveform in modern circuits can be distorted or its frequency can be different than 50/60 Hz. Frequency of earth fault (residual) current influences tripping of residual current devices which are widely used in low voltage systems. This paper presents the behaviour...
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Vibro-Electrical Behavior of a Viscoelastic Piezo-Nanowire in an Elastic Substrate Considering Stress Nonlocality and Microstructural Size-Dependent Effects
PublicationThis research deals with dynamics response of a Pol/BaTiO3 nanowire including viscosity influences. The wire is also impressed by a longitudinal electric field. Hamilton's principle and Lagrangian strains are employed in conjunction with a refined higher-order beam theory in order to derive equations of motion. By combining nonlocality and small size...
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Analiza obiegów kogeneracyjnych z silnikami tłokowymi i mikroturbi-nami
PublicationPrzeprowadzono analizę dla układów kogeneracyjnych z mikroturbinami wykorzystującymi ciepło odpadowe z silników tłokowych. Rozważono cztery główne źródła ciepła odpadowego z silników tłokowych: spaliny wylotowe, woda chłodząca silnik, olej smarny i ciepło z systemu turbodaładowania. Obliczenia przeprowadzono dla silników General Electric Jerbacher typów: J320 GS-C25 i J416 GS-B05. Uwzględniono różne czynniki robocze siłowni (zarówno...
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Yields and Time-of-Flight Spectra of Neutral High-Rydberg Fragments at the K Edges of the CO2 Molecule
PublicationWe have studied the production of neutral fragments in high-Rydberg (HR) states at the C 1s and O 1s edges of the CO2 molecule by performing two kinds of experiments. First, the yields of neutral HR fragments were measured indirectly by ionizing such fragments in a static electric field and by collecting resulting singly charged positive ions as a function of the photon energy. Such measurements reveal not only excitations below...
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Strategies for Achieving Energy Neutrality in Biological Nutrient Removal Systems – a Case Study of the Slupsk WWTP (northern Poland)
PublicationThe paper presents a model-based evaluation of technological upgrades on the energy and cost balance in a large biological nutrient removal wastewater treatment plant (WWTP) in the city of Slupsk (northern Poland). The proposed upgrades include chemically enhanced primary sludge removal and reduction of the nitrogen load in the deammonification process employed for reject water treatment. Simulations enabled to estimate the increased...
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Mathematical modelling of the overhead contact line for the purpose of diagnostics of pantographs
PublicationThe overhead contact line (OCL) is the most effective way for supplying railway electric vehicles. The increase of the speed of the vehicles increases power consumption and requires ensuring proper cooperation of pantographs with OCL. The paper describes the novel mathematical model of the OCL system and the simulation results. The primary objective is a more accurate analysis to increase the reliability of the evaluation of monitoring...