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Search results for: microwave%20reactors
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Size Reduction of Microwave Couplers by EM-Driven Optimization
PublicationThis work addresses simulation-driven design optimization of compact microwave couplers that explicitly aims at circuit footprint area reduction. The penalty function approach allows us to minimize the area of the circuit while ensuring a proper power division between the output ports and providing a sufficient bandwidth with respect to return loss and isolation around the operating frequency. Computational cost of the optimization...
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Artificial Neural Networks in Microwave Components and Circuits Modeling
PublicationArtykuł dotyczy wykorzystania sztucznych sieci neuronowych (SNN) w projektowaniu i optymalizacji układów mikrofalowych.Zaprezentowano podstawowe zasady i założenia modelowania z użyciem SNN. Możliwości opisywanej metody opisano wykorzystując przykładowyprojekt anteny łatowej. Przedstawiono różne strategie modelowania układów, które wykorzystują możliwości opisywanej metody w połączeniu zwiedzą mikrofalową. Porównano również dokładność...
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Application of microwaves for sewage sludge conditioning
PublicationArtykuł dotyczy wpływu promieniowania mikrofalowego na odwadnianie osadów ściekowych. Przeprowadzono pomiary parametrów charakteryzujących podatność osadów ściekowych na odwadnianie: opór właściwy, czas ssania kapilarnego oraz zawartość suchej masy w osadzie po odwirowaniu. Stwierdzono poprawę odwadnialności osadów kondycjonowanych promieniowaniem mikrofalowym, zależną ilościowo od rodzaju preparowanych osadów. Zastosowanie podwójnego...
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The Mott-Schottky characteristics of microwave pulsed-plasma polymerized allylamine by DEIS analysis
Open Research DataThe dataset contains the results obtained for the Mott-Schottky analysis of the microwave pulsed-plasma polymerized allylamine using the multifrequency perturbation signal with Dynamic Electrochemical Impedance Spectroscopy (DEIS) technique. The results were obtained using the perturbation composed of the elementary signals with a frequency range between...
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Hybrid Modulation for Modular Voltage Source Inverters with Coupled Reactors
PublicationThis paper proposes and discusses a concept of a hybrid modulation for the control of modular voltage source inverters with coupled reactors. The use of coupled reactors as the integrating elements leads to significant reduction in the size and weight of the circuit. The proposed modulation combines novel coarsely quantized pulse amplitude modulation (CQ-PAM) and innovative space-vector pulse width modulation (SVPWM). The former...
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36-pulse rectifier with a system of coupled three-phase reactors
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Advanced vanadium modified steels for high pressure hydrogen reactors
PublicationPrzedstawiono nową generację stali chromowo-molibdenowych zmodyfikowanych wanadem, przeznaczonych do budowy wodorowych reaktorów i porównano ze stalami konwencjonalnymi. Opisano mikrostrukturę, właściwości i zastosowanie stali. Podkreślono wpływ mikrostruktury nowych stali na przebieg degradacji środowiskowej.
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Modular multipulse voltage source inverters with integrating coupled reactors
PublicationA novel approach to the voltage source inverters (VSI) construction is presented in the paper. The invented inverter structures allow to operate several DC/AC converters in parallel resulting in lower voltage distortions at extremely low switching frequency. The research presented in the paper describes such a parallel operation of the VSI’s which is possible thanks to the use of coupled inductors. The eighteen-pulse and twenty-four-pulse...
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Low harmonic multipulse voltage converters using coupled reactors
PublicationThis paper presents a novel approach to the multi pulse voltage converters (VC), especially voltage source inverters (VSI) and matrix converters (MC) based on several typical identical modules connected in parallel using coupled reactors. Such arrangements resulting in lower voltage distortions at extremely low switching frequency. The proposed arrangement was validated by simulation. Laboratory models of 18- and 24pulse 3-level...
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Journal of Microwaves, Optoelectronics and Electromagnetic Applications
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Piotr Jamroz dr hab. inż.
PeoplePiotr Jamroz graduated from Wroclaw University of Technology, Faculty of Chemistry in 1998 and obtained his PhD from the same university in 2003. Currently he works as an associate professor at Wroclaw University of Science and Technology, Faculty of Chemistry, Division of Analytical Chemistry and Chemical Metallurgy. His research interests are related to generation and diagnostics of different kinds of plasma sources, including...
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Direct Constraint Control for EM-Based Miniaturization of Microwave Passives
PublicationHandling constraints imposed on physical dimensions of microwave circuits has become an important design consideration over the recent years. It is primarily fostered by the needs of emerging application areas such as 5G mobile communications, internet of things, or wearable/implantable devices. The size of conventional passive components is determined by the guided wavelength, and its reduction requires topological modifications,...
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Effect of microwave and convection heating on selected nutrients of human milk
PublicationThe aim of this study was to determine the influence of the microwave heating method (MWH) on selected determinants of the nutritional value of human milk (HM) and compare to the effect exerted by the standard convection heating (CH) method, including holder pasteurization (HoP). It was showed that using MWH under conditions assumed to ensure microbiological safety, changes in the level of the nutrients were not observed. In these...
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Novel MNZ-type microwave sensor for testing magnetodielectric materials
PublicationA novel microwave sensor with the mu-near-zero (MNZ) property is proposed for testing magnetodielectric material at 4.5 GHz. The sensor has a double-layer design consisting of a microstrip line and a metal strip with vias on layers 1 and 2, respectively. The proposed sensor can detect a unit change in relative permittivity and relative permeability with a difference in the operating frequency of 45 MHz and 78 MHz, respectively....
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Interactive Application for Visualization of the Basic Phenomena in RF and Microwave Devices
PublicationAn interactive computer application visualizing the basic phenomena in RF and microwave devices is presented. Such kind of educational package can be a very helpful tool for the students as well as for the teachers (of electronics and related fields). This paper is focused on three exemplary problems only and involves: movement of electric charge, filtering of electromagnetic waves and interference phenomena in antenna arrays. The...
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Study of anticorrosion and microwave absorption properties of NiZn ferrite pigments
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A Novel Reactor for Microwave Hydrothermal Scale-up Nanopowder Synthesis
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Microwave solvothermal synthesis and characterization of manganese-doped ZnO nanoparticles
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Hydrothermal, microwave and mechanochemical modification of amorphous zirconium phosphate structure
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Y2O3:Eu nanocrystals as biomarkers prepared by a microwave hydrothermal method
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Multivariate models of inter-resonator couplings for microwave filter synthesis
PublicationArtykuł przedstawia technikę budowy modeli częstotliwości rezonansowej, współczynnika sprzężenia między rezonatorami oraz sprzężenia ze źródłem/obciążeniem. Przedstawiony jest model siedmiu zmiennych uwzglęgniający topologię rezonatorów. Na podstawie modelu wykonana została synteza filtrów mikrofalowych.
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Automated microwave planar filter design with generalized Chebyshev characteristics.
PublicationIn this paper a technique of automatization of design of microwave filters with generalized Chebyshev characteristics is presented. A full wave electromagnetic simulator linked with the Matlab computing environment is used to ensure a rigorous numerical analysis while at the same time allowing automatization. To decrease time of optimization and overall design process, the Cauchy interpolation technique was used. An automated design...
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Microwave-assisted preparation of potato starch silicated with silicic acid
PublicationApplication of microwave irradiation for the silication of granular potato starch with silicic acid, and the properties of silicated starch were investigated. Potato starch was esterified on 20 min microwave irradiation of starch with silicic acid, applying the power of 450 or 800Wand, for comparison, on 120 min convectional heating of the reagent blend at 100 ◦C. The degree of esterification and the reaction efficiency did not...
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A New Microwave Ceramic – Polymer Composite with 0-3 Connectivity
PublicationGoal of the present research was to fabricate and study two-phase BiNbO4//PVDF composites with 0-3 connectivity. Such composite consists of there-dimensionally connected polymer matrix loaded with dielectric ceramic particles. In the present case BiNbO4 powder acted as an active phase (dispersed phase) whereas polyvinylidene fluoride (PVDF) acted as a non-active (passive) phase (matrix). BiNbO4//PVDF composites with the volume...
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Microwave treatment in waste rubber recycling – recent advances and limitations
PublicationEnvironmentally-friendly microwave heating is increasingly used in polymer chemistry and technology. The selectivity and highly efficiency in the heat transfer present a huge advantage in systems based on recycling, improving their productivity and economic competitiveness. In case of the industrial recycling of waste rubbers, especially end-of-life tires, microwave-induced devulcanization and pyrolysis are nowadays considered...
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Study of anticorrosion and microwave absprption properties of NiZn ferrite pigments
PublicationPurpose - The purpose of this paper is to report the electrochemical verification of anticorrosive properties of NiZn ferrites as pigments in protective coatings and evaluation of their microwave absorbing properties. Design/methodology/approach - Ferrites, represented by formula NixZn(1-x)Fe2O4, where x=0, 0.2, 0.4, 0.6, 0.8, 1.0, were synthesized using a ceramic method. The samples of ferrites were examined by X-ray diffraction...
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Reliable Microwave Modeling By Means of Variable-Fidelity Response Features
PublicationIn this work, methodologies for low-cost and reliable microwave modeling are presented using variable-fidelity response features. The two key components of our approach are: (i) a realization of the modeling process at the level of suitably selected feature points of the responses (e.g., S-parameters vs. frequency) of the structure at hand, and (ii) the exploitation of variable-fidelity EM simulation data, also for the response...
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Frequency-dependent coupling model for microwave band-pass filter
PublicationThe goal of this work was to create a circuit model which represents frequency-dependent coupling between microwave resonators. Our models are designed for in-line filters. The frequency-dependent coupling enables one to realize a transmission zero which is not possible in classical approach with frequency independent inverters. In addition, the proposed model allows us to observe out-of-band behavior, e.g. spurious resonance....
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Rheology of potato starch chemically modified with microwave-assisted reactions
PublicationNative potato starch was sulfated, selenated, borated, silicated and zincatated by means of microwave-assisted reactions with varying doses of relevant reagents. Resulting products were characterized involving rheological behavior of pastes, their weight-average molecular weight (Mw), and radius of gyration (Rg). Most of the pastes showed shear-thinning behavior, with the flow behavior index (n) below unity. The pastes of starch...
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Computationally Efficient Design Optimization of Compact Microwave and Antenna Structures
PublicationMiniaturization is one of the important concerns of contemporary wireless communication systems, especially regarding their passive microwave components, such as filters, couplers, power dividers, etc., as well as antennas. It is also very challenging, because adequate performance evaluation of such components requires full-wave electromagnetic (EM) simulation, which is computationally expensive. Although high-fidelity EM analysis...
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On the Use of Selected 4th Generation Nuclear Reactors in Marine Power Plants
PublicationThis article provides a review of the possibility of using different types of reactors to power ships. The analyses were carried out for three different large vessels: a container ship, a liquid gas carrier and a bulk carrier. A novelty of this work is the analysis of the proposal to adapt marine power plants to ecological requirements in shipping by replacing the conventional propulsion system based on internal combustion engines...
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Comparison of nitrogen and VFA removal pathways in autotrophic and organotrophic anammox reactors
PublicationOrganotrophic anammox is a promising process for treating both nitrogen and organic containing wastewater than that of the traditional autotrophic anammox for sole nitrogen removal. However pathways of nitrogen removal particularly at metagenomic level in both processes are still unknown. Here we report, metabolic pathways of nitrogen removal in two lab-scale sequencing batch reactors (SBR), one autotrophic and another organotrophic...
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Effects of dispersion on predicting longitudinal concentration profiles in activated sludge reactors
PublicationW pracy przedstawiono wpływ dyspersji na prognozowanie stężeń azotu amonowego w komorach osadu czynnego w oczyszczalni ścieków Gdańsk-Wschód. W tym celu wykorzystano jednowymiarowe równanie adwekcji-dyspersji z członem źródłowym (szybkością nitryfikacji). Współczynnik dyspersji został wyznaczony na podstawie pomiarów znacznika fluoroscencyjnego. Model został zweryfikowany w oparciu o pomiary stężeń azotu w 6 sekcjach komory tlenowej...
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Comparison of cadmium adsorption process on barley straw in batch and flow reactors
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Evaluation of empirical formulae for estimation of the longitudinal dispersion in activated sludge reactors
PublicationBadania traserowe są szeroko stosowane do oceny hydrauliki reaktorów. Jednak w komorach osadu czynnego interpretacja wyników jest trudna z uwagi na recyrkulacje wewnętrzne i recyrkulację osadu z osadnika. Wzory empiryczne mogą być alternatywną metodą oceny warunków hydraulicznych w komorach. Celem tych badań było sprawdzenie czterech wzorów empirycznych na obliczanie współczynnika dyspersji hydrodynamicznej w oparciu o wyniki badań...
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Adrian Bekasiewicz dr hab. inż.
PeopleAdrian Bekasiewicz received the MSc, PhD, and DSc degrees in electronic engineering from Gdansk University of Technology, Poland, in 2011, 2016, and 2020, respectively. In 2014, he joined Engineering Optimization & Modeling Center where he held a Research Associate and a Postdoctoral Fellow positions, respectively. Currently, he is an Associate Professor with Gdansk University of Technology, Poland. His research interests include...
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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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Effect of convection and microwave heating on the retention of bioactive components in human milk
PublicationBioactive substances are very important components of human milk (HM), especially for premature newborns. The effects of convection (CH) and microwave heating (MWH) at 62.5 and 66 °C, on the level of selected bioactive components of HM: lysozyme (LZ), lactoferrin (LF), secretory immunoglobulin A (sIgA), basal lipase (BL), cytokine TGF-2, vitamin C and total antioxidant capacity (TAC) was compared. Regardless of the used heating methods...
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Metamaterial-Based Sub-Microwave Electromagnetic Field Energy Harvesting System
PublicationThis paper presents the comprehensive analysis of the sub-microwave, radio frequency band resonant metastructures’ electromagnetic properties with a particular emphasis on the possibility of their application in energy harvesting systems. Selected structures based on representative topologies of metamaterials have been implemented in the simulation environment. The models have been analyzed and their substitute average electromagnetic...
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Reduced-Cost Constrained Modeling of Microwave and Antenna Components: Recent Advances
PublicationElectromagnetic (EM) simulation models are ubiquitous in the design of microwave and antenna components. EM analysis is reliable but CPU intensive. In particular, multiple simulations entailed by parametric optimization or uncertainty quantification may considerably slow down the design processes. In order to address this problem, it is possible to employ fast metamodels. Here, the popular solution approaches are approximation...
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Microwave plasma application in decomposition and steam reforming of model tar compounds
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Paramagnetism of cobalt-doped ZnO nanoparticles obtained by microwave solvothermal synthesis
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Size control mechanism of ZnO nanoparticles obtained in microwave solvothermal synthesis
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Microwave-assisted hydrothermal synthesis and electrochemical studies of α- and h-MoO3
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Low order autoregressive (AR) models for FDTD analysis of microwave filters.
PublicationArtykuł opisuje zastosowanie modeli AR w celu poprawy efektywności analizy struktur filtrujących metodą różnic skończonych w dziedzinie czasu (FD-TD). Opisanych jest szereg kryteriów pozwalających na automatyczne tworzenie modeli AR sygnałów czasowych, w tym wybór fragmentu odpowiedzi układu stanowiący podstawę ekstrakcji współczynników modelu, współczynnika decymacji oraz rzędu modelu. Skuteczność wprowadzonych kryteriów...
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Hybrid analysis of microwave components in cylindrical coordinates with function expansion in subdomains.
PublicationW artykule zaproponowano wydajną metodę przyspieszenia analizy FDTD, poprzez podział dziedziny obliczeniowej i zastosowanie różnych algorytmów w różnych elementach dziedziny. Zaproponowano uniwersalną metodę łączenia techniki PEE (Partial Eigenfunction Expansion)i niezmodyfikowanej FDTD w jednej analizie. Uzyskano redukcję liczby zmiennych oraz wydłużenie kroku czasowego.
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The Design of Cavity Resonators and Microwave Filters Applying Shape Deformation Techniques
PublicationThis article introduces shape deformation as a new approach to the computer-aided design (CAD) of high-frequency components. We show that geometry deformation opens up new design possibilities and offers additional degrees of freedom in the 3-D modeling of microwave structures. Such design flexibility is highly desirable if the full potential of additive manufacturing (AM) is to be exploited in the fabrication of RF and microwave...
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Reduced-Cost Microwave Modeling Using Constrained Domains and Dimensionality Reduction
PublicationDevelopment of modern microwave devices largely exploits full-wave electromagnetic (EM) simulations. Yet, simulation-driven design may be problematic due to the incurred CPU expenses. Addressing the high-cost issues stimulated the development of surrogate modeling methods. Among them, data-driven techniques seem to be the most widespread owing to their flexibility and accessibility. Nonetheless, applicability of approximation-based...
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A Highly Sensitive Planar Microwave Sensor for Detecting Direction and Angle of Rotation
PublicationThis article presents a technique based on a modified complementary split-ring resonator (CSRR) to detect angular displacement and direction of rotation with high resolution and sensitivity over a wide dynamic range. The proposed microwave planar sensor takes advantage of the asymmetry of the sensor geometry and measures the angle of rotation in terms of the change in the relative phase of the reflection coefficients. The sensor...
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Book review: Simulation-Driven Design Optimisation and Modelling for Microwave Engineering
PublicationCelem książki jest przedstawienie aktualnego stanu badań dotyczących projektowania układów mikrofalowych poprzez modelowanie i optymalizacje wspomagane symulacjami elektromagnetycznymi. Grupa międzynarodowych ekspertów zajmujących się rożnymi aspektami komputerowo wspomaganego projektowania układów mikrofalowych, podsumowuje i dokonuje przeglądu ostatnich osiągnięć w tej dziedzinie oraz przedstawia szereg praktycznych zastosowań....