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Search results for: 5g, switched-beam antenna, reconfigurable antenna, beam control, lens antenna, antenna array, direction-of- arrival estimation, internet-of-things, wireless sensor networks, espar antenna, eres antenna, 3d printing.
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Modeling of Heat Source Based on Parameters of Electron Beam Welding Process
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Numerical Simulation of Electron Beam Welding Process of Inconel 706 Sheets
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E-Beam Irradiation and Ozonation as an Alternative to the Sulphuric Method of Wine Preservation
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On some aspects of torsional buckling of thin-walled I-beam columns
PublicationW pracy podsumowano wyniki badań zjawiska wyboczenia skrętnego prętów o przekroju dwuteowym. Zbadano wpływ początkowego wygięcia giętnego na wartość siły krytycznej wyboczenia skrętnego. Z zasady stacjonarności energii potencjalnej wyprowadzono równania różniczkowe wyboczenia skrętnego. Wartość siły krytycznej wyznaczono stosując podejście perturbacyjne. Wyniki analityczne porównano z rezultatami otrzymanymi za pomocą 6-parametrowej...
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Torsional buckling of thin walled I beam column with warping stiffeners.
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Numerical simulation of a thin-walled beam with warping stiffeners undergoing torsion
PublicationW pracy rozwinięto koncepcję zastosowania superelementów węzłowych do modelowania stężeń konstrukcyjnych w belkach cienkościennych. Przeprowadzono analizę pracy belek cienkościennych o bisymetrycznym przekroju otwartym ze stężeniami bimomentowymi w formie przepon i przewiązek.
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Experimental an numerical investigation of wave propagation in composite beam with an additional mass
PublicationW pracy przedstawiono wyniki badań eksperymentalnych i symulacji numerycznych ilustrujace wpływ dodatkowej masy na propagacje fali Lamba w belce kompozytowej.
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Selected acoustic images of the Gdansk Bay
PublicationThe main goal of the paper is to describe the results of sounding the Gdansk Bay seabed by using a parametric sub-bottom profiler, multibeam echosounder and side scan sonar. Quality of dsata obtained during trials depends interalia on a proper location of antenna to reduce influence of pitch, roll and heave motions as well as ship noise.
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Stability analysis of single-walled carbon nanotubes embedded in winkler foundation placed in a thermal environment considering the surface effect using a new refined beam theory
PublicationThis article is devoted to investigate the stability of different types of Single Walled Carbon Nanotubes (SWCNTs) such as zigzag, chiral, and armchair types which are rested in Winkler elastic foundations exposing to both the low and high temperature environments. Also, the Surface effects which include surface energy and surface residual stresses, are taken into consideration in this study. It may be noted that the surface energy...
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Assessment of Thermal Stresses in Asphalt Mixtures at Low Temperatures Using the Tensile Creep Test and the Bending Beam Creep Test
PublicationThermal stresses are leading factors that influence low-temperature cracking behavior of asphalt pavements. During winter, when the temperature drops to significantly low values, tensile thermal stresses develop as a result of pavement contraction. Creep test methods can be suitable for the assessment of low-temperature properties of asphalt mixtures. To evaluate the influence of creep test methods on the obtained low-temperature...
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Stability analysis of nanobeams in hygrothermal environment based on a nonlocal strain gradient Timoshenko beam model under nonlinear thermal field
PublicationThis article is dedicated to analyzing the buckling behavior of nanobeam subjected to hygrothermal environments based on the principle of the Timoshenko beam theory. The hygroscopic environment has been considered as a linear stress field model, while the thermal environment is assumed to be a nonlinear stress field based on the Murnaghan model. The size-dependent effect of the nanobeam is captured by the nonlocal strain gradient...
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Michał Rewieński dr inż.
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Robust Parameter Estimation and Output Prediction for Reactive Carrier-Load Nonlinear Dynamic Networks
PublicationIn this paper an extension of on-line model simplification technique for a class of networked systems, namely reactive carrier-load nonlinear dynamic networked system (RCLNDNS), kept within point-parametric model (PPM) framework is addressed. The PPM is utilised to acquire a piece wise constant time-varying parameter linear structure for the RCLNDNS suitable for the on-line one step ahead prediction that may be applied to monitoring...
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Focused ion beam-based microfabrication of boron-doped diamond single-crystal tip cantilevers for electrical and mechanical scanning probe microscopy
PublicationIn this paper, the fabrication process and electromechanical properties of novel atomic force microscopy probes utilising single-crystal boron-doped diamond are presented. The developed probes integrate scanning tips made of chemical vapour deposition-grown, freestanding diamond foil. The fabrication procedure was performed using nanomanipulation techniques combined with scanning electron microscopy and focused ion beam technologies....
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Modes of Failure Analysis in Reinforced Concrete Beam Using Laser Scanning and Synchro-Photogrammetry - How to apply optical technologies in the diagnosis of reinforced concrete elements?
PublicationThe following paper reveal the limitations and possibilities of terrestrial laser scanning technology adaptation in diagnostics of reinforced concrete beams. In this paper, authors present potential spectrum of TLS use in modes of failure analysis of R-C beams and determines under which conditions the laser technologies might be applied. Research was carried out at the Regional Laboratory of Structural Engineering at Gdansk University...
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Acceleration of Electromagnetic Simulations on Reconfigurable FPGA Card
PublicationIn this contribution, the hardware acceleration of electromagnetic simulations on the reconfigurable field-programmable-gate-array (FPGA) card is presented. In the developed implementation of scientific computations, the matrix-assembly phase of the method of moments (MoM) is accelerated on the Xilinx Alveo U200 card. The computational method involves discretization of the frequency-domain mixed potential integral equation using...
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Softly Switched Robustly Feasible Model Predictive Control for Nonlinear Network Systems
PublicationIt is common that an efficient constrained plant operation under full range of disturbance inputs require meeting different sets of control objectives. This calls for application of model predictive controllers each of them being best fit into specific operating conditions. It further requires that not only designing robustly feasible model predictive controllers is needed to satisfy the real plant state/output constraints, but...
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Protecting Wireless Mesh Networks Against Adverse Weather Conditions
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Cost minimization in wireless networks with a bounded and unbounded number of interfaces
PublicationPraca dotyczy problemu minimalizacji energii poprzez selektywne odłączanie urządzeń komunikacyjnych w wielointerfejsowych sieciach bezprzewodowych w taki sposób, by zapewnić realizację wymaganego grafu połączeń. Sformułowano problem optymalizacyjny, podano wyniki dotyczące jego trudności i zaproponowano algorytmy optymalizacyjne. Rozważono zarówno wariant, w którym liczba interfejsów komunikacyjnych jest parametrem stałym (narzuconym...
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Study on transmission quality in cellular 4G and 5G networks between 2019–2021: Impact of the COVID-19 pandemic on the level of provided services by operating base transceiver stations
PublicationThe COVID-19 pandemic has significantly limited user mobility, not least among students. Remote learning had a particular impact on resource allocation in relation to using terrestrial cellular networks, especially 4G systems in urban agglomerations. This paper presents the results of a quality evaluation of an outdoor environment, carried out between 2019 and 2021 on the campus of a technical university. Annual studies are conducted...
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Multi-objective optimization of expensive electromagnetic simulation models
PublicationVast majority of practical engineering design problems require simultaneous handling of several criteria. For the sake of simplicity and through a priori preference articulation one can turn many design tasks into single-objective problems that can be handled using conventional numerical optimization routines. However, in some situations, acquiring comprehensive knowledge about the system at hand, in particular, about possible...
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Internet system for supply and temperature control in server rooms
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Magnetic field mapping along a NV-rich nanodiamond-doped fiber
PublicationIntegration of NV−-rich diamond with optical fibers enables guiding quantum information on the spin state of the NV− color center. Diamond-functionalized optical fiber sensors have been demonstrated with impressive sub-nanotesla magnetic field sensitivities over localized magnetic field sources, but their potential for distributed sensing remains unexplored. The volumetric incorporation of diamonds into the optical fiber core allows...
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Kamil Trzebiatowski mgr inż.
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Noise Analysis of Continuous GPS Time Series of Selected EPN Stations to Investigate Variations in Stability of Monument Types
PublicationThe type of monument that a GPS antenna is placed on plays a significant role in noise estimation for each permanent GPS station. In this research 18 Polish permanent GPS stations that belong to the EPN (EUREF Permanent Network) were analyzed using Maximum Likelihood Estimation (MLE). The antennae of Polish EPN stations are placed on roofs of buildings or on concrete pillars. The analyzed data covers a period of 5 years from 2008...
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Dual polarization antennas for UHF RFID readers
PublicationThis paper presents various concepts of switching polarization in patch antenna dedicated for UHF RFID readers. Proposed designs allow for switching between linear and circular polarization. The first design does not require electronic switching as the polarization can be changed by choosing one of two available feeding terminals. Two remaining designs use PIN diode or FET SPDT switch.
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Macromodels for Efficient Analysis of Open-Region Problems Using the Finite Element Method
PublicationThis paper presents a local model-order reduction, called macromodeling, applied to speed-up the simulations of open-region problems, analyzed by means of finite element method. This technique is illustrated by a numerical example, which deals with a dielectric resonator antenna (DRA). The obtained results show that the proposed approach is reliable and can significantly increase the standard finite element method efficiency.
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Resonant Frequencies in the Open Microstrip Structures Placed on Curved Surfaces
PublicationThe paper presents the research on open microstrip structures placed on curved surfaces such as cylindrical, elliptical or spherical. The numerical analysis of investigated structures is based on expansion of electric and magnetic fields into suitable function series. Utilizing the continuity conditions the boundary problem is formulated which is solved with the use of method of moments. The investigated structures find application...
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Failure of cold-formed beam: How does residual stress affect stability?
PublicationIn machine industry, stresses are often calculated using simple linear FEM analysis. Occasional failures of elements designed in such a way require recomputation by means of more sophisticated methods, eg. including plasticity and non-linear effects. It usually leads to investigation of failure causes and improvement of an element in order to prevent its unwanted behavior in the future. The study presents the case where both linear...
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Performance of the CMS hadron calorimeter with cosmic ray muons and LHC beam data
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Acousto-optic interaction of a Gaussian laser beam with an ultrasonic wave of cylindrical symmetry
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Assessment of flexural beam behaviour theories used for dynamics and wave propagation problems
PublicationW pracy przedstawiono i porównano teorie belek zginanych począwszych od teorii elementarnych, aż do teorii wyższych rzędów. Przedstawiono krzywe dyspersi dla poszczególnych teorii i na ich podstawione oszacowano zakres stosowalności danej teorii.
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On numerical analysis of a thin-walled I-beam with warping stiffenes undertorsional loads
PublicationPraca jest streszczeniem referatu wygłoszonego na międzynarodowej konferencji Metody Komputerowe w Mechanice, Wisła, 3-6 czerwca 2003. Przedstawiono problem numerycznej analizy belek cienkościennych ze stężeniami. Omówiono dwa modele jednowymiarowe: jeden bazujący na koncepcji skupionej sztywności bimomentowej, a drugi na zastosowaniu superelementu MES. Otrzymane wyniki porównano z rezultatami analizy MES przy zastosowaniu dyskretyzacji...
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Cavitation erosion of some alloys manufactured on steel and iron surfaces by laser beam.
PublicationPrzedstawiono badania odporności kawitacyjnej stali węglowej 45 odpornej na korozję 2H13 i technicznego żelaza po ich obróbce laserowej. Warstwę wierzchnią wybranych stali wzbogacono w różne pierwiastki stopowe i badano odporność kawitacyjną na stanowisku z wirującą tarczą. Stwierdzono niską odporność kawitacyjną dla warstw o obniżonej zdolności do utwardzania pod wpływem obciążeń kawitacyjnych oraz silną zależność odporności...
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Influence of laser beam machining on the cavitation resistance of Fe-Cr-Co clad.
PublicationW pracy przedstawiono wpływ laserowego nagrzewania bezzmiany stanu skupienia i laserowego przetapiania napoin ze stopu Fe-Cr-Co na ich odporność kawitacyjną. Badania kawitacyjne prowadzono na stanowisku z wirującą tarczą. Plastyczne odkształcenia powierzchni określano za pomocą analizy obrazów erodowanych powierzchni. Uzyskane rezultaty wskazują, że laserowo obrabiane powierzchnie miały różną podatność do plastycznego odkształcania...
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Cavitation erosion of chromium-manganese and chromium-cobalt coatings processed by laser beam
PublicationPrzedstawiono wyniki badań erozji kawitacyjnej napoin wykonanych za pomocą elektrod chromowo-manganowych i chromowo-niklowych oraz obrobionych wiązką lasera CO2 o mocy 1000 W. Próbki poddawano obciążeniom kawitacyjnym na stanowisku z wirującą tarczą. Zaobserwowano wzrost odporności kawitacyjnej napoin, w których dokonano przetopienia ich powierzchni promieniowaniem lasera.
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Effects of preheating on laser beam–welded NSSC 2120 lean duplex steel
PublicationDuplex stainless steels show sustainable alternative for the conventional austenitic grades, with higher strength, higher resistance against stress corrosion cracking, and lower purchase cost. Thus, duplex stainless steel gains more attention in construction, oil and gas, and chemical industries. Among duplex stainless steels, low nickel and low molybdenum alloyed lean duplex stainless steel are a cost-efective substitution of...
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Detection of defects in PMMA beam using shear waves - numerical simulation and experiment
PublicationTest doświadczalny falami sprężystymi jest częścią systemu diagnostycznego belek. Autorzy badają pole przyspieszeń wywołane przepływem fal ultradźwiękowych i jego modyfikacje wynikające z wprowadzonych uszkodzeń belki. Artykuł porównuje wyniki eksperymentalne z symulacjami numerycznymi MES. The experimental test introduced in the paper is the part of the diagnostic system utilizing the elastic waves. The authors investigate the...
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Broadband/Dual-band Metal-Mountable UHF RFID Tag Antennas: A Systematic Review. Taxonomy Analysis, Standards of Seamless RFID System Operation, Supporting IoT implementations, Recommendations and Future Directions
PublicationThe employment of broadband/dual-band ultra-high frequency (UHF) radio frequency identification (RFID) tag antennas contributes to the growth of RFID technology, with many potential implications, such as the increase of international trade, and reducing costs thereof. This study presents all reported articles on RFID tags for metal objects that can work seamlessly across different countries. Moreover, it addresses all available...
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Performance-Driven Inverse/Forward Modeling of Antennas in Variable-Thickness Domains
PublicationDesign of contemporary antenna systems is a challenging endeavor. The difficulties are partially rooted in stringent specifications imposed on both electrical and field characteristics, demands concerning various functionalities, but also constraints imposed upon the physical size of the radiators. Furthermore, conducting the design process at the level of full-wave electromagnetic (EM) simulations, otherwise dictated by reliability,...
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System Loss Model for Body-to-Body Networks in Indoor and Outdoor Environments
PublicationA system loss model for body-to-body networks in indoor and outdoor environments is proposed in this paper, based on measurements taken at 2.45 GHz. The influence of the type of environment, antenna visibility and user mobility on model parameters has been investigated. A significant impact of mutual antennas’ placement and their visibility is shown. The proposed model fits well to empirical data, with the average root mean square...
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Deep learning in the fog
PublicationIn the era of a ubiquitous Internet of Things and fast artificial intelligence advance, especially thanks to deep learning networks and hardware acceleration, we face rapid growth of highly decentralized and intelligent solutions that offer functionality of data processing closer to the end user. Internet of Things usually produces a huge amount of data that to be effectively analyzed, especially with neural networks, demands high...
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Closed Form Constraint Equations Used to Express Frictionless Slip of Multibody Systems Attached to Finite Elements—Application to a Contact between a Double Pendulum and a Beam
PublicationThis paper focuses on the numerical modeling of the dynamics of mechanical systems. Robots that can inspect high-voltage lines inspired this research. Their control systems must anticipate potential grab positions appropriately. We intend to formulate equations dedicated to the numerical description of the robot/cable contact. The investigated problem is not straightforward, since parts of the modeled systems are numerically inhomogeneous....
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The effect of impacted third molars on second molar external root resorption, a cross-sectional cone beam computed tomography study
PublicationBackground: Third molars have the highest prevalence of impaction in teeth and can cause pathological damage on the adjacent second molars. This study aims to evaluate the effects of factors related to impacted third molars on external root resorption (ERR) in adjacent second molars using cone-beam computed tomography (CBCT). Material and Methods: In CBCTs, the effect of impacted third molars on the root surface of adjacent second...
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Usage of parametric echosounder with emphasis on buried object searching.
PublicationThe purpose of this article is to present the results of investigation to search for buried objects. The paper will contain echograms and other means of visualization from buried pipe placed between area of W?adys?awowo and gas platform and interesting in terms of the number of small and medium-sized unidentified objects found in the muddy bottom at different depths localized in the Gulf of Puck - results will be presented also...
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Automatic resource identification for FPGA-based reconfigurable measurement and control systems with mezzanines in FMC standard
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Modelling of wastewater treatment plant for monitoring and control purposes by state - space wavelet networks
PublicationMost of industrial processes are nonlinear, not stationary, and dynamical with at least few different time scales in their internal dynamics and hardly measured states. A biological wastewater treatment plant falls into this category. The paper considers modelling such processes for monitorning and control purposes by using State - Space Wavelet Neural Networks (SSWN). The modelling method is illustrated based on bioreactors of...
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Network lifetime maximization in wireless mesh networks for machine-to-machine communication
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Cloud-to-ground lightning dipole moment from simultaneous observations by ELF receiver and combined direction finding and time-of-arrival lightning detection system
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Feedline Alterations for Optimization-Based Design of Compact Super-Wideband MIMO Antennas in Parallel Configuration
PublicationThis letter presents a technique for size reduction of wideband multiple-input-multiple-output (MIMO) antennas. Our approach is a two-stage procedure. At the first stage, the antenna structure is modified to improve its impedance matching. This is achieved through incorporation of an n-section tapered feedline, followed by reoptimization of geometry parameters. Reducing the maximum in-band reflection well beyond the acceptance...