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Search results for: SWITCHED-BEAM ANTENNA, RECONFIGURABLE ANTENNA, STEERABLE ANTENNA, ELECTRONICALLY STEERABLE PARASITIC ARRAY RADIATOR (ESPAR) ANTENNA, INDOOR LOCALIZATION, RSS.
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Reliable data-driven modeling of high-frequency structures by means of nested kriging with enhanced design of experiments
PublicationData-driven (or approximation) surrogate models have been gaining popularity in many areas of engineering and science, including high-frequency electronics. They are attractive as a way of alleviating the difficulties pertinent to high computational cost of evaluating full-wave electromagnetic (EM) simulation models of microwave, antenna, and integrated photonic components and devices. Carrying out design tasks that involve massive...
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Design and Experimental Validation of a Metamaterial-Based Sensor for Microwave Imaging in Breast, Lung, and Brain Cancer Detection
PublicationThis study proposes an innovative geometry of a microstrip sensor for high-resolution microwave imaging (MWI). The main intended application of the sensor is early detection of breast, lung, and brain cancer. The proposed design consists of a microstrip patch antenna fed by a coplanar waveguide with a metamaterial layer-based lens implemented on the back side, and an artificial magnetic conductor (AMC) realized on as a separate...
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Investigation of RH effect on uncommon limonene ozonolysis products and SOA formation in indoor air with real time measurement techniques
PublicationScientific interest in SOA influence on indoor air quality increases since last 20 years. It is well known, that particles of nano-sized diameter pose a threat for human health causing, among others: eye, upper airway irritation, inflammatory response in cells, worsening asthma, hypertension, diabetes, and central nervous dysfunction. Terpenes are reactive VOCs, commonly emitted in indoor air and considered to be SOA precursors...
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Data Compression in Ultrasonic Network Communication via Sparse Signal Processing
PublicationThis document presents the approach of using compressed sensing in signal encoding and information transferring within a guided wave sensor network, comprised of specially designed frequency steerable acoustic transducers (FSATs). Wave propagation in a damaged plate was simulated using commercial FEM-based software COMSOL. Guided waves were excited by means of FSATs, characterized by the special shape of its electrodes, and modeled...
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Radio Channel Measurements in Body-to-Body Communications in Different Scenarios
PublicationThis paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving...
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Radio Channel Measurements in Body-to-Body Communications in Different Scenarios
PublicationThis paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving...
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An Off-Body Narrowband and Ultra-Wide Band Channel Model for Body Area Networks in a Ferry Environment
PublicationIn the article an off-body narrowband and ultra-wide band channel model for Body Area Networks in a ferry environment is described. A mobile, heterogeneous measurement stand, that consists of three types of devices: miniaturized mobile nodes, stationary reference nodes and a data acquisition server was developed. A detailed analysis of both radio channels parameters in untypical indoor environment was carried out. An analysis of...
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Softly switched model predictive control for control of integratedwastewater treatment system at medium time scale.
PublicationW przypadku gdy system jest sterowany za pomocą jednej, uniwersalnej strategii sterowania w pełnym zakresie jego obciążeń, powstają poważne trudności w znalezieniu optymalnego sterowania. W celu jak najlepszego dopasowania strategii sterowania do panujący warunków, zdefiniowano trzy stany operacyjne: normalny, zakłóceniowy oraz awaryjny. Dla tych stanów zaprojektowano odpowiednie strategie sterowania. W związku z tym pojawia się...
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Influence of a Radio Frequency on RF Fingerprinting Accuracy Based on Ray Tracing Simulation
PublicationIn this paper the influence of a radio signal frequency on performance of Indoor Positioning System based on fingerprinting has been examined using ray-tracing simulations. It has been simulated how spatial distribution of an RF signal strength change with the signal’s frequency. The results were used to show its’ impact on the behavior of localization algorithms that are employing RSS measurements to determine node’s position...
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Damage Detection of Steel-Concrete Composite Beam
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The effect of mechanical coupling on the beam pattern of a multielementarray
PublicationW artykule opisano nową metodę redukcji listków bocznych hydroakustycznej anteny wieloelementowej. Wykorzystano tu efekt ważenia amplitud sygnałów odbieranych przez poszczególne elementy poprzez kontrolowane ich mechaniczne sprzężenie. Opisane zostały wyniki badań kilku modeli anten zbudowanych z pięciu elementów. Wyniki badań zostały zweryfikowane obliczeniami symulacyjnymi. Stwierdzono, zarówno na drodze eksperymentalnej jak...
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Crack identification in cantilever beam using wavelets
PublicationPrzedstawiono metodę identyfikacji zniszczeń przy użyciu transformacji falkowej. Rozpatrzono przykład belki wspornikowej. Pokazano, że transformacja falkowa wykrywa miejsce zniszczenia.
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An Improvement of Global Complex Roots and Poles Finding Algorithm for Propagation and Radiation Problems
PublicationAn improvement of the recently developed global roots finding algorithm has been proposed. The modification allows to shorten the computational time by reducing the number of function calls. Moreover, both versions of the algorithms (standard and modified) have been tested for numerically defined functions obtained from spectral domain approach and field matching method. The tests have been performed for three simple microwave...
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Pattern matching localization in ZigBee wireless sensor networks.
PublicationLokalizacja typu Pattern matching w sieciach sensorów bezprzewodowych ZigBee.Prezentacja metod implementacji algorytmów lokalizacji. Praktyczne zastosowanie i testowanie lokalizacji sieci ZigBee.
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Localization of sound sources with dual acoustic vector sensor
PublicationThe aim of the work is to estimate the position of sound sources. The proposed method uses a setup of two acoustic vector sensors (AVS). The intersection of azimuth rays from each AVS should indicate the position of a source. In practice, the result of position estimation using this method is an area rather than a point. This is a result of inaccuracy of the individual sensors, but more importantly, of the influence of a source...
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Localization in wireless sensor networks based on zigbee platform
PublicationW artykule porównano dwie różne metody lokalizacji w sieciach sensorów bezprzewodowych. Jedną z metod jest implementacja sprzętowa algorytmu w układzie nadawczo odbiorczym CC2431. Drugą metodą jest implementacja programowa. Wyniki testów przeprowadzonych na otwartym terenie oraz w pomieszczeniach zamkniętych zostały przedstawione i porównane w pracy.
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Wavelet analysis in detection and localization of damage in engineering structures
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Vibration based damage localization in non-homogeneous structures
PublicationPrzedmiotem badań jest identyfikacja lokalnych uszkodzeń w konstrukcjach budowlanych. Przedstawione są trzy metody bazujące na teorii drgań. Są to metody badające: częstości własne, podatność i krzywizny postaci drgań układu. Skuteczność metod pokazana jest na przykładach symulacji komputerowych, wykonanych dla belki swobodnie podpartej, wspornikowej oraz podwieszonej kładki dla pieszych. Dodatkowo zaprezentowane są wyniki badań...
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New approach to localization of clicks in archive speech signals.
PublicationPrzedstawiono problem lokalizacji zniekształceń impulsowych w archiwalnych sygnałach mowy. Pokazano, że detekcja oparta na dwuzakresowym modelu autoregresyjnym i przetwarzanie dwukierunkowe pozwala uzyskać znaczącą poprawę działania w stosunku do istniejących metod lokalizacji zniekształceń.
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Shear localization in granular bodies with micro-polar hypoplasticity.
PublicationW książce przedstawiono wyniki numerycznej analizy lokalizacji odkształceń stycznych w materiałach granulowanych dla różnych problemów brzegowych quasi-statycznych. Obliczenia wykonano przy zastosowaniu metody elementów skończonych i mikropolarnego modelu hipoplastycznego.
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Modeling of strain localization in granular and quasi-brittle materials
PublicationW artykule przedstawiono wyniki symulacji lokalizacji odkształceń w materiałach granulowanych i kruchych. Zasosowano różne modele w ramach mechaniki ośrodków ciągłych i dyskretnych. Wyniki obliczeń porównano z doswiadczeniami.
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A picocellular UMTS/TDD overlay on GSM system for indoor environment
PublicationW pracy przedstawiono nakładkę CDMA na system GSM. Nakładka użytkuje system UMTS w trybie TDD i jest przeznaczona do funkcjonowania wewnątrz budynków w obszarze makrokomórki systemu GSM. Wyniki badań przedstawione w pracy ukazują znaczny wzrost efektywności wykorzystania tego samego pasma przez oba systemy i uzyskanie znacznej pojemności dla nakładki bez degradacji pracy systemu GSM
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TiO2-based photocatalysts in indoor swimming pool air purification
PublicationWzrastająca ilość basenów kąpielowych i aquaparków jest obecnie wyzwaniem dla naukowców zajmujących się badaniem i kontrolowaniem powietrza hali basenowej. Mikroorganizmy powstałe w powietrzu hali stanowią ogromne zagrożenie dla zdrowia. Ponadto, w fazie gazowej obecne są także uboczne produkty dezynfekcji (DBP), które mogą mieć szkodliwy wpływ zarówno na kąpiących się, jak i personel. W pracy omówiono potencjalne zagrożenia spowodowane...
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An Empirical Model for the Polarisation Characteristics of Indoor Off-Body Channels
PublicationThis paper presents an analysis of the polarisation characteristics for the channel in dynamic off-body communications, and an empirical channel model, based on measurements performed at 2.45 GHz in an office environment. Body presence and propagation conditions have a strong influence on signal depolarisation. The model assumes three components for the total path loss: mean path loss, represented by a log-distance function with...
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Permeation passive sampling as a tool for the evaluation of indoor air quality
PublicationOkreślono stężenie średnie ważone w czasie wybranych lotnych związków organicznych w powietrzu ośmiu pomieszczeniach mieszkalnych na terenie miasta Gdańska. Do pobierania próbek analitów z powietrza wewnętrznego zastosowano permeacyjny dozymetr pasywny typu pudełkowego oraz technikę dynamiczną (urządzenie przepływowe z rurką sorpcyjną). Porównano wyniki uzyskane w wyniku zastosowania w/w technik pobierania próbek analitów.
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Unconventional and user-friendly sampling techniques of semi-volatile organic compounds present in an indoor environment: An approach to human exposure assessment
PublicationThe commonly applied solutions used to assess the potential risk of human exposure to semi-volatile organic compounds (SVOCs) are based on the investigation of biological samples collected in an invasive or non-invasive manner. For SVOCs, which are typically introduced to humans through the respiratory system, dermal adsorption, or digestive system, sampling solutions generally used in the indoor environments are classified as...
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Jacobi and gauss-seidel preconditioned complex conjugate gradient method with GPU acceleration for finite element method
PublicationIn this paper two implementations of iterative solvers for solving complex symmetric and sparse systems resulting from finite element method applied to wave equation are discussed. The problem under investigation is a dielectric resonator antenna (DRA) discretized by FEM with vector elements of the second order (LT/QN). The solvers use the preconditioned conjugate gradient (pcg) method implemented on Graphics Processing Unit (GPU)...
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Application of gpr method in diagnostics of reinforced concrete structures
PublicationThis paper presents an application of the ground penetration method (GPR) for diagnostics of reinforced concrete structures. In situ measurements were conducted for three civil engineering structures: the ground floor structure, the abutment of the railway viaduct and the concrete well. The dual polarized ground penetrating radar with the antenna operating at a center frequency of 2 GHz was used for GPR surveys. Three different...
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Application of shifted Chebyshev polynomial-based Rayleigh–Ritz method and Navier’s technique for vibration analysis of a functionally graded porous beam embedded in Kerr foundation
PublicationPresent study is dealt with the applicability of shifted Chebyshev polynomial based Rayleigh-Ritz method and Navier’s technique on free vibration of Functionally Graded (FG) beam with uniformly distributed porosity along the thickness of the beam. The material properties such as Young’s modulus, mass density, and Poisson’s ratio are also considered to vary along the thickness of the FG beam as per the power-law exponent model....
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Nested Kriging with Variable Domain Thickness for Rapid Surrogate Modeling and Design Optimization of Antennas
PublicationDesign of modern antennas faces numerous difficulties, partially rooted in stringent specifications imposed on both electrical and field characteristics, demands concerning various functionalities (circular polarization, pattern diversity, band-notch operation), but also constraints imposed upon the physical size of the radiators. Conducting the design process at the level of full-wave electromagnetic (EM) simulations, otherwise...
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Reduced-Cost Design Optimization of High-Frequency Structures Using Adaptive Jacobian Updates
PublicationElectromagnetic (EM) analysis is the primary tool utilized in the design of high-frequency structures. In vast majority of cases, simpler models (e.g., equivalent networks or analytical ones) are either not available or lack accuracy: they can only be used to yield initial designs that need to be further tuned. Consequently, EM-driven adjustment of geometry and/or material parameters of microwave and antenna components is a necessary...
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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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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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Effects of Surface Energy and Surface Residual Stresses on Vibro-Thermal Analysis of Chiral, Zigzag, and Armchair Types of SWCNTs Using Refined Beam Theory
PublicationIn this article, vibration characteristics of three different types of Single-Walled Carbon Nanotubes (SWCNTs) such as armchair, chiral, and zigzag carbon nanotubes have been investigated considering the effects of surface energy and surface residual stresses. The nanotubes are embedded in the elastic substrate of the Winkler type and are also exposed to low and high-temperature environments. A new refined beam theory namely, one-variable...
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Stability of softly switched multiregional dynamic output controllers with a static antiwindup filter: A discrete-time case
PublicationThis paper addresses the problem of model-based global stability analysis of discrete-time Takagi–Sugeno multiregional dynamic output controllers with static antiwindup filters. The presented analyses are reduced to the problem of a feasibility study of the Linear Matrix Inequalities (LMIs), derived based on Lyapunov stability theory. Two sets of LMIs are considered candidate derived from the classical common quadratic Lyapunov...
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Impact of laser beam welding on mechanical behaviour of 2.25Cr–1Mo (P22) steel
PublicationThe use of welding processes in the manufacturing and repair of structures intended for the energy industry plays a key role in the guarantee of a continuous supply of fossil fuels, which is the basic condition for ensuring energy security. A square butt joint of 10 mm thick plate of 2.25Cr–1Mo (P22) steel was fabricated by autogenous laser beam welding process and then post-weld heat treatment (PWHT) for two sets of process parameters...
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Numerical Determination of the Load-Bearing Capacity of a Perforated Thin-Walled Beam in a Structural System with a Steel Grating
PublicationThis article presents the results of numerical simulations of a structural system consisting of steel perforated thin-walled beams and a steel grating. The simulations were conducted using the finite element method. The analysis took into account physical and geometric nonlinearity as well as the contact between the steel grating and the beams. The main goal of the research was to develop load-bearing curves for the main beam in...
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UNDERWATER NOISE GENERATED BY A SMALL SHIP IN THE SHALLOW SEA
PublicationStudy of the sea noise has been a subject of interest for years. The first work of this scope were published at the turn of the twentieth century by Knudsen (KNUDSEN et al., 1948) and G. Wenz (WENZ, 1962). Disturbances called "shipping noise" are one of the important components of the sea noise. In this work the results of an experimental research of underwater noise produced by a small ship of a classic propulsion are...
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Diver Observations by Means of Acoustic Methods
PublicationSearching for objects, especially small ones, moving under water near its the free surface, is always not an easy task. Designing tools for the detection of such targets is a real challenge when the possibility of a terrorist attack is a real threat. This paper presents some aspects of diver detection by means of acoustics methods, both active (side scan sonar) and passive ones (linear receiving antenna). This approach is quite...
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Badanie i analiza efektywności alokacji strumieni danych w heterogenicznej sieci WBAN
PublicationW niniejszej dysertacji doktorskiej poddano dyskusji efektywność alokacji strumieni danych w heterogenicznej radiowej sieci WBAN (Wireless Body Area Networks). Biorąc pod uwagę dynamiczny rozwój nowoczesnych sieci radiokomunikacyjnych piątej generacji (5G), którego część stanowią radiowe sieci działające w obrębie ciała człowieka, bardzo ważnym aspektem są metody maksymalizujące wykorzystanie dostępnych zasobów czasowo –częstotliwościowych...
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Jakość powietrza wewnętrznego - lotne związki organiczne jako wskaźnik jakości powietrza wewnętrznego = Indoor air quality - volatile organic compounds as an indicator of the quality of indoor air
PublicationPomieszczenia zamknięte z jednej strony są barierą chroniącą przed negatywnymi czynnikami środowiska, zmiennymi warunkami pogodowymi - deszczem, wiatrem, niską lub wysoką temperaturą, z drugiej jednak strony - w zamkniętych wnętrzach nastepuje często kumulacja toksycznych związków organicznych i nieorganicznych, co nie pozostaje bez wpływu na ludzkie zdrowie.Głównym celem badań jest oszacowanie jakości powietrza wewnętrznego pod...
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4-Point beam tensile test on a soft adhesive
PublicationAn adhesive butt joint with a soft bondline has been studied. A series of experiments was conducted on test pieces constituted of aluminium adherends bonded with a low modulus epoxy adhesive, ScotchWeld™ 2216. The joint was subjected to four point bending, in tension/compression loading, under constant deflection rate, with the bondline being parallel to the applied load. The objective was to examine and evaluate crack nucleation...
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TB11 test for short w-beam road barrier
PublicationFEM (Finite Element Method) is well-suited and widely used tool for simulating a range of phenomena: from these with simple and static behaviour, up to those complicated, highly nonlinear and involving many contacts. In present paper we use one of the advantages of FEM: parametric study could be easily performed and is more economical than series of in-situ tests. If recommended practices is carefully followed, results obtained...
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VRML visualization of pelagic fish movement in the echosounder beam.
PublicationPrzedstawiono konstrukcję dynamicznych trójwymiarowych echogramów dla danych pochodzących z przeszukiwań akustycznych zrealizowanych przy pomocy echosondy z rozszczepioną wiązką. Wizualizację zrealizowano wykorzystując język opisu wirtualnej rzeczywistości VRML.
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Flexural shera wave propagation in cracked composite beam.
PublicationW pracy przedstawiono model i wyniki analizy wpływu peknięcia na propagacje fali gietno-scinajacej w belce kompozytowej.
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Genetic algorithm for fatique crack detection in Timoshenko beam.
PublicationW pracy przedstawiono metodę detekcji peknięć zmęczeniowych w początkowej fazie ich rozwoju. Algorytm detekcji wykorzystuje metodę algorytmów genetycznych połączoną z metodą gradientową. Funkcja celu oparta została o zmiany w propagujacej fali sprężystej.
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Pressure distribution and beam pattern of the parametric acoustic arrays.
PublicationPrzedstawiono model matematyczny i wyniki badań teoretycznych zjawiska oddziaływań fal dla źródeł parametrycznych. Model matematyczny zbudowano w oparciu o równanie KZK. Do rozwiązania zagadnienia zastosowano metodę różnic skończonych. Badano zmiany ciśnienia fal wybranych częstotliwości w obrębie wiązki akustycznej oraz charakterystyki kierunkowe dla kołowych źródeł parametrycznych generujących fale różnych częstotliwości.
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Implementation of Haar wavelet, higher order Haar wavelet, and differential quadrature methods on buckling response of strain gradient nonlocal beam embedded in an elastic medium
PublicationThe present investigation is focused on the buckling behavior of strain gradient nonlocal beam embedded in Winkler elastic foundation. The first-order strain gradient model has been combined with the Euler–Bernoulli beam theory to formulate the proposed model using Hamilton’s principle. Three numerically efficient methods, namely Haar wavelet method (HWM), higher order Haar wavelet method (HOHWM), and differential quadrature method...
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Determination of bisphenol A in size fractions of indoor dust from several microenvironments
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Indoor atmospheric degradation of historical metal objects studied by spectroscopic techniques
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