Search results for: MICROWAVE ENGINEERING
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Comparative Greenness Evaluation
PublicationGreenness of analytical procedure is multivariable aspect as many greenness criteria should be taken into consideration. On the other hand, modern analytical chemistry offers dozens of analytical procedures, based on different sample preparation and final determination techniques that are used for the determination of a given analyte in a given matrix. For such complex decision-making processes, multi-criteria decision analysis...
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Nanocrystalline diamond sheets as protective coatings for fiber-optic measurement head
PublicationFiber-optic sensors find numerous applications in science and industry, but their full potential is limited because of the risk of damaging the measurement head, in particular, due to the vulnerability of unprotected tips of the fiber to mechanical damage and aggressive chemical agents. In this paper, we report the first use of a new nanocrystalline diamond structure in a fiber-optic measurement head as a protective coating of...
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Planar Microwave Bragg Reflector Resonant Dielectric Sensor
PublicationIn this paper, a periodic structure is used to design a microwave Bragg reflector with the help of hexagonal lattice, which provides a 5 GHz wide stopband between the low-pass band with cut-off frequency 2.6 GHz and the bandpass response with start and stop frequency 7.8 GHz and 10.5 GHz, respectively. A defect in lattice allows passing a narrowband signal at 6 GHz which is found, from the dispersion relation, to be in the region...
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Do You Know What You Drink? Comparative Research on the Contents of Radioisotopes and Heavy Metals in Different Types of Tea from Various Parts of the World
PublicationThe aim of this study was to assess the potential health risks of radioactive elements and heavy metals ingested through the consumption of various types of tea imported to the Polish market (black, green, red, oolong and white). The concentrations [Bq/kg] of radionuclides (40K, 137Cs, 226Ra, 210Pb and 228Th) in tea leaves before and after brewing were measured using γ-ray spectrometry with high-purity germanium (HPGe). The concentrations...
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Unraveling the role of boron dimers in the electrical anisotropy and superconductivity in boron-doped diamond
PublicationWe use quantum mechanics (QM) to determine the states formed by B dopants in diamond. We find that isolated B sites prefer to form BB dimers and that the dimers pair up to form tetramers (BBCBB) that prefer to aggregate parallel to the (111) surface in the <110> direction, one double layer below the H-terminated surface double layer. These tetramers lead to metallic character (Mott metal Insulator Transition) with holes in the...
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Novel Complementary Resonator for Dielectric Characterization of Substrates Based on Permittivity and Thickness
PublicationThis paper presents a novel complementary resonator featuring high sensitivity, low fabrication cost, and improved performance. The proposed structure consists of a complementary concentric square and circular ring resonator (CCSCRR) with multiple splits to enhance the inductance of the resonator. The proposed CCSCRR is coupled to a microstrip transmission line with an impedance of fifty ohms to create a high-sensitivity sensor....
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Nanocrystalline CVD Diamond Coatings on Fused Silica Optical Fibres: Optical Properties Study
Publicationpre-treatment by dip coating in two detonation nanodiamond (DND) seeding media has been studied. The DND suspension in ethyl alcohol and dispersion of DND in dimethyl sulfoxide (DMSO) with polyvinyl alcohol (PVA) were chosen for the seeding purpose. The grain size distribution of nanodiamond particles in both seeding media was kept at the same level (approximately 1050 nm). After the seeding nanocrystalline diamond lms were deposited...
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Modification of Titanium (IV) Dioxide with Small Silver Nanoparticles: Application in Photocatalysis
PublicationThe surface of commercial TiO2 compounds (P25 and ST01) has been modified with Ag nanoparticles induced by radiolysis. On P25, the Ag nanoclusters are very small (1−2 nm) and homogeneous in size while on ST01, two populations of nanoparticles are obtained, small nanoparticles (1−2 nm) and larger ones (mean diameter 7 to 12 nm depending on the silver loading). The photocatalytic properties of Ag-modified TiO2 have been studied for...
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Silver-modified titania with enhanced photocatalytic and antimicrobial properties under UV and visible light irradiation
PublicationCommercial titania photocatalysts were modified with 2 wt% of silver by photodeposition. The properties of the samples were characterized by DRS, XPS, XRD, FE-SEM and STEM. The modified samples exhibited activity under visible light and enhanced activity under UV irradiation for 2-propanol and acetic acid oxidation, respectively. The time-resolved microwave conductivity (TRMC) analysis indicated that enhanced activity (2.5–8-fold...
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Characterization of Optical and Electrical Properties of Transparent Conductive Boron-Doped Diamond thin Films Grown on Fused Silica
PublicationA conductive boron-doped diamond (BDD) grown on a fused silica/quartz has been investigated. Diamond thin films were deposited by the microwave plasma enhanced chemical vapor deposition (MW PECVD). The main parameters of the BDD synthesis, i.e. the methane admixture and the substrate temperature were investigated in detail. Preliminary studies of optical properties were performed to qualify an optimal CVD synthesis and film parameters...
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Accurate simulation-driven modeling and design optimization of compact microwave structures
PublicationCost efficient design optimization of microwave structures requires availability of fast yet reliable replacement models so that multiple evaluations of the structure at hand can be executed in reasonable timeframe. Direct utilization of full-wave electromagnetic (EM) simulations is often prohibitive. On the other hand, accurate data-driven modeling normally requires a very large number of training points and it is virtually infeasible...
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Comparing traffic intensity estimates employing passive acoustic radar and microwave Doppler radar sensor
PublicationThe purpose of our applied research project is to develop an autonomous road sign with built-in radar devices of our design. In this paper, we show that it is possible to calibrate the acoustic vector sensor so that it can be used to measure traffic volume and count the vehicles involved in the traffic through the analysis of the noise emitted by them. Signals obtained from a Doppler radar are used as a reference source. Although...
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A Novel Trust-Region-Based Algorithm with Flexible Jacobian Updates for Expedited Optimization of High-Frequency Structures
PublicationSimulation-driven design closure is mandatory in the design of contemporary high-frequency components. It aims at improving the selected performance figures through adjustment of the structure’s geometry (and/or material) parameters. The computational cost of this process when employing numerical optimization is often prohibitively high, which is a strong motivation for the development of more efficient methods. This is especially...
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Design and Microwave-Assisted Synthesis of TiO2-Lanthanides Systems and Evaluation of Photocatalytic Activity under UV-LED Light Irradiation
PublicationThe TiO2-Eu and TiO2-La systems were successfully synthesized using the microwave method. Based on the results of X-ray diffraction analysis, it was found that regardless of the analyzed systems, two crystal structures were noted for the obtained samples: anatase and rutile. The analysis, such as XPS and EDS, proved that the doped lanthanum and europium nano-particles are present only on the TiO2 surface without disturbing the...
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Efficient Gradient-Based Algorithm with Numerical Derivatives for Expedited Optimization of Multi-Parameter Miniaturized Impedance Matching Transformers
PublicationFull-wave electromagnetic (EM) simulation tools have become ubiquitous in the design of microwave components. In some cases, e.g., miniaturized microstrip components, EM analysis is mandatory due to considera¬ble cross-coupling effects that cannot be accounted for otherwise (e.g., by means of equivalent circuits). These effects are particularly pronounced in the structures in¬volving slow-wave compact cells and their numerical...
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BEYOND5 Building the fully European supplY chain on RFSOI, enabling New RF Domains for Sensing, Communication, 5G and beyond
ProjectsProject realized in Department of Microwave and Antenna Engineering according to 876124 agreement from 2020-05-28
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Fabrication of high-density nitrogen-vacancy (NV) center-enriched diamond particles through methyl trityl amine (C20H19N) seeding
PublicationDiamond particles (DPs) show promise for advanced applications in bioimaging and quantum sensing due to the presence of defect centers. This work reports a unique growth process for diamond particles composed of nitrogen-vacancy centers (NV-DPs) using a methyl trityl amine (C20H19N) diamondoid seed, which acts as a nitrogen source for NV creation. Growth was performed via microwave plasma-assisted chemical vapor deposition in a...
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Investigation of use of hydrophilic/hydrophobic NADESs for selective extraction of As(III) and Sb(III) ions in vegetable samples: Air assisted liquid phase microextraction and chemometric optimization
PublicationIn this paper, a green, cost-effective sample preparation method based on air assisted liquid phase microextraction (AA-LPME) was developed for the simultaneous extraction of As(III) and Sb(III) ions from vegetable samples using hydrophilic/hydrophobic natural deep eutectic solvents (NADESs). Central composite design was used for the optimization of extraction factors including NADES volume, extraction cycle, pH, and curcumin concentration....
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Boron-Doped Diamond/GaN Heterojunction—The Influence of the Low-Temperature Deposition
PublicationWe report a method of growing a boron-doped diamond film by plasma-assisted chemical vapour deposition utilizing a pre-treatment of GaN substrate to give a high density of nucleation. CVD diamond was deposited on GaN substrate grown epitaxially via the molecular-beam epitaxy process. To obtain a continuous diamond film with the presence of well-developed grains, the GaN substrates are exposed to hydrogen plasma prior to deposition....
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A comprehensive review on Ginger (Zingiber officinale) as a potential source of nutraceuticals for food formulations: Towards the polishing of gingerol and other present biomolecules
PublicationCurrently, ginger is one the most consumed plants when dealing with the treatments of various illnesses. So far, it is known that various biologically active molecules, such as gingerols, shogaols and zingerone, among others, are the main responsible for specific biological activities, opening a new window for its utilization as a nutraceutical in foods. In pioneering extraction processes, solvent extraction has been initially...
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Structural and physico-mechanical properties of natural rubber/GTR composites devulcanized by microwaves: Influence of GTR source and irradiation time
PublicationGround tire rubber from car and truck was modified using microwave irradiation at variable time. The irradiated ground tire rubber was used as filler in composites based on natural rubber. The composites, with high content of ground tire rubber, were prepared using an internal batch mixer and subsequently cross-linked at 160℃. The influence of the ground tire rubber source (car/truck) and irradiation time on structure, physico-mechanical...
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Tuning of the Electrochemical Properties of Transparent Fluorine-doped Tin Oxide Electrodes by Microwave Pulsed-plasma Polymerized Allylamine
PublicationWe report here the dry, one-step, and low-temperature modification of FTO surfaces using pulsed plasma polymerization of allylamine (PPAAm). PPAAm/FTO surfaces were characterized by X-ray photoelectron spectroscopy, spectroscopic ellipsometry, and contact angles to understand the morphological, structural, and optical properties. FTO were coated with a very thin layer of adherent cross-linked, pinhole-, and additive-free allylamine...
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Growth and Isolation of Large Area Boron‐Doped Nanocrystalline Diamond Sheets: A Route toward Diamond‐on‐Graphene Heterojunction
PublicationMany material device applications would benefit from thin diamond coatings, but current growth techniques, such as chemical vapor deposition (CVD) or atomic layer deposition require high substrate and gas‐phase temperatures that would destroy the device being coated. The development of freestanding, thin boron‐doped diamond nanosheets grown on tantalum foil substrates via microwave plasma‐assisted CVD is reported. These diamond...
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Rapid simulation-driven design of miniaturised dual-band microwave couplers by means of adaptive response scaling
PublicationOne of the major challenges in the design of compact microwave structures is the necessity of simultaneous handling of several objectives and the fact that expensive electromagnetic (EM) analysis is required for their reliable evaluation. Design of multi-band circuits where performance requirements are to be satisfied for several frequencies at the same time is even more difficult. In this work, a computationally efficient design...
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Boron-Enhanced Growth of Micron-Scale Carbon-Based Nanowalls: A Route toward High Rates of Electrochemical Biosensing
PublicationIn this study, we have demonstrated the fabrication of novel materials called boron-doped carbon nanowalls (B:CNWs), which are characterized by remarkable electrochemical properties such as high standard rate constant (k°), low peak-to-peak separation value (ΔE) for the oxidation and reduction processes of the [Fe(CN)6]3–/4– redox system, and low surface resistivity. The B:CNW samples were deposited by the microwave plasma-assisted...
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Enhanced electrochemical kinetics of highly-oriented (111)-textured boron-doped diamond electrodes induced by deuterium plasma chemistry
PublicationNovel highly-oriented (111)-textured boron-doped diamond electrodes (BDDD) featuring high electrochemical activity and electrode stability toward electrochemical analytics were fabricated by deuterium-rich microwave plasma CVD. The high flux deuterium plasma-induced preferential formation of (111)-faceted diamond as revealed by XRD. The highly-oriented diamond surface exhibited improved boron dopant incorporation and activation,...
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Low-strain sensor based on the flexible boron-doped diamond-polymer structures
PublicationA free-standing high boron-doped diamond nanosheet (BDDNS) has been fabricated for the development of a flexible BDDNS strain senor. High boron-doped diamond was initially grown on a tantalum substrate in a microwave plasma-assisted chemical vapor deposition method, and was then transferred to a Kapton polymer substrate to fabricate the flexible BDDNS/Kapton device. Before performing the transfer process, the thin BDDNS’s morphology...
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Microwave-assisted synthesis of a TiO2-CuO heterojunction with enhanced photocatalytic activity against tetracycline
PublicationA microwave method was used for the synthesis of TiO2-CuO oxide systems. A detailed investigation was made of the effect of the molar ratio of components (TiO2:CuO=9:1, 7:3, 5:5, 3:7, 1:9) on the crystalline structure and morphology. Transmission electron microscopy (TEM) confirmed the presence of octahedral and rod-shaped titania particles and sheet copper(II) oxide particles; moreover, HRTEM analysis indicated the presence of...
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Volumetric incorporation of NV diamond emitters in nanostructured F2 glass magneto-optical fiber probes
PublicationIntegration of optically-active diamond particles with glass fibers is a powerful method of scaling diamond's magnetic sensing functionality. We propose a novel approach for the integration of diamond particles containing nitrogen-vacancy centers directly into the fiber core. The core is fabricated by stacking the preform from 790 soft glass canes, drawn from a single rod dip-coated with submicron diamond particles suspended in...
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Wytwarzanie i charakterystyka cienkich warstw diamentowych na podłożach ze szkła kwarcowego, w szczególności na światłowodach włóknistych, dla zastosowań w sensorach optoelektronicznych
PublicationGłównym celem naukowym prac badawczych przeprowadzonych w rozprawie było wytwarzanie i modyfikacja funkcjonalności cienkich, przewodzących warstw diamentowych syntezowanych na podłożach optycznych. W ramach przeprowadzonych badań wytworzono szereg warstw diamentowych o specyficznych właściwościach optycznych i elektrycznych, mających na celu wykazanie możliwości wykorzystania takich struktur dla celów sensorycznych. Do poprawy...
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Selection of circuit geometry for miniaturized microwave components based on concurrent optimization of performance and layout area
PublicationThe paper presents a framework for automated EM-driven circuit geometry selection of miniaturized microwave components. Selection of a particular layout is based directly on miniaturization rates achieved for a set of candidate circuit geometries. Size reduction of the considered structures is obtained by replacing their main building blocks (i.e., conventional transmission lines) with slow-wave composite cells and meander lines....
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Enhanced boron doping of thin diamond films grown in deuterium-rich microwave plasma
PublicationThe boron-doped diamond thin films were growth in deuterium rich microwave plasma in CVD process. The mechanism of influence of plasma composition on boron doping level was studied using optical emission spectroscopy. Deuterium rich plasma results in an increased dissociation of B2H6 precursor and intense boron-radicals' production. In consequence, a higher doping level of diamond films was observed by means of Laser Induced Breakdown...
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Bandwidth-size design trade-offs for compact spline-parameterised patch couplers by means of electromagnetic-driven multi-objective optimisation
PublicationBroad bandwidth and small size are the key performance figures for contemporary microwave couplers. These requirements are conflicting, i.e. improvement of one generally leads to degradation of the other assuming fixed topology of the circuit at hand. From a designer's perspective, the knowledge about available design trade-offs is indispensable as it permits for tailoring the circuit for particular applications as well as comparing...
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Application of commercial microwave links (CMLs) attenuation for quantitative estimation of precipitation
PublicationPrecipitation estimation models are typically sourced by rain gauges, weather radars and satellite observations. A relatively new technique of precipitation estimation relies on the network of Commercial Microwave Links (CMLs) employed for cellular communication networks: the rain-inducted attenuation in the links enables the precipitation estimation. In the paper, it is analysed to what extent the precipitation derived from CML...
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Local impedance imaging of boron-doped polycrystalline diamond thin films
PublicationLocal impedance imaging (LII) was used to visualise surficial deviations of AC impedances in polycrystalline boron-doped diamond (BDD). The BDD thin film electrodes were deposited onto the highly doped silicon substrates via microwave plasma-enhanced CVD. The studied boron dopant concentrations, controlled by the [B]/[C] ratio in plasma, ranged from 1 × 1016 to 2 × 1021 atoms cm−3. The BDD films displayed microcrystalline structure,...
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Optical and electrical properties of ultrathin transparent nanocrystalline boron-doped diamond electrodes
PublicationThe optical properties of ultrathin (less than 100 nm) boron-doped nanocrystalline diamond (B-NCD) film were investigated in a wavelength range of 200 ÷ 20000 nm. The B-NCD refractive index showed values close to that of monocrystalline diamond (n = 2.45) in a broad wavelength range (450 ÷ 4000 nm). A transmittance up to 70% and the average film thickness of 70 nm were achieved. A special cone-shaped shim was used in the deposition...
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Accelerated design optimization of miniaturized microwave passives by design reusing and Kriging interpolation surrogates
PublicationElectromagnetic (EM) analysis has become ubiquitous in the design of microwave components and systems. One of the reasons is the increasing topological complexity of the circuits. Their reliable evaluation—at least at the design closure stage—can no longer be carried out using analytical or equivalent network representations. This is especially pertinent to miniaturized structures, where considerable EM cross-coupling effects occurring...
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Bioactive hybrid metal-organic framework (MOF)-based nanosensors for optical detection of recombinant SARS-CoV-2 spike antigen
PublicationFast, efficient, and accurate detection of SARS-CoV-2 spike antigen is pivotal to control the spread and reduce themortality of COVID-19. Nevertheless, the sensitivity of available nanobiosensors to detect recombinant SARS-CoV-2 spike antigen seems insufficient. As a proof-of-concept, MOF-5/CoNi2S4 is developed as a low-cost, safe, and bioactive hybrid nanostructure via the one-pot high-gravity protocol. Then, the porphyrin, H2TMP,...
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Improved Design Closure of Compact Microwave Circuits by Means of Performance Requirement Adaptation
PublicationNumerical optimization procedures have been widely used in the design of microwave components and systems. Most often, optimization algorithms are applied at the later stages of the design process to tune the geometry and/or material parameter values. To ensure sufficient accuracy, parameter adjustment is realized at the level of full-wave electromagnetic (EM) analysis, which creates perhaps the most important bottleneck due to...
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Boron doped Nanocrystalline Diamond-Carbon Nanospike Hybrid Electron Emission Source
PublicationElectron emission signifies an important mechanism facilitating the enlargement of devices that have modernized large parts of science and technology. Today, the search for innovative electron emission devices for imaging, sensing, electronics, and high-energy physics continues. Integrating two materials with dissimilar electronic properties into a hybrid material is an extremely sought-after synergistic approach envisioning a...
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Editorial for the special issue on advances in forward and inverse surrogate modeling for high-frequency design
PublicationThe design of modern‐day high‐frequency devices and circuits, including microwave/RF, antenna and photonic components, historically has relied on full‐wave electromagnetic (EM) simulation tools. Initially used for design verification, EM simulations are nowadays used in the design process itself, for example, for finding optimum values of geometry and/or material parameters of the structures of interest. In a growing number of...
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Application of autoencoder to traffic noise analysis
PublicationThe aim of an autoencoder neural network is to transform the input data into a lower-dimensional code and then to reconstruct the output from this code representation. Applications of autoencoders to classifying sound events in the road traffic have not been found in the literature. The presented research aims to determine whether such an unsupervised learning method may be used for deploying classification algorithms applied to...
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Modification of titanium dioxide with platinum ions and clusters: application in photocatalysis
PublicationW celu polepszenia właściwości fotokatalitycznych, TiO2 (komercyjny-P25 oraz syntezowany metoda zol-żel) był domieszkowany za pomocą jonów lub klasterów [Pt3(CO)6]62- platyny. Własności fizyczne fotokatalizatorów były badane za pomocą elektronowego mikroskopu transmisyjnego (TEM), dyfraktometru rentgenowskiego (XRD) oraz analizatora powierzchni właściwej (BET). Dyfuzyjna spektrometria odbiciowa (DRS) została zastosowana w celu...
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Schottky Junction-Driven Photocatalytic Effect in Boron-Doped Diamond-Graphene Core–Shell Nanoarchitectures: An sp3/sp2 Framework for Environmental Remediation
PublicationSelf-formation of boron-doped diamond (BDD)-multilayer graphene (MLG) core–shell nanowalls (BDGNWs) via microwave plasma-enhanced chemical vapor deposition is systematically investigated. Here, the incorporation of nitrogen brings out the origin of MLG shells encapsulating the diamond core, resulting in unique sp3/sp2 hybridized frameworks. The evolution mechanism of the nanowall-like morphology with the BDD-MLG core–shell composition...
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Optimization of vortex-assisted supramolecular solvent-based liquid liquid microextraction for the determination of mercury in real water and food samples
PublicationA novel method was developed for sample preparation for spectrophotometric determination of Hg(II) in water and food samples. The method was based on vortex-assisted supramolecular solvent-assisted liquid-liquid microextraction (VA-SUPRASs-LLME). Analytical parameters such as pH, chelating agent, solvent type and volume, vortex time and salting out effect were optimized. Surface and normal probability plots were drawn for the variables...
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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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A comprehensive review on current and emerging technologies toward the valorization of bio‐based wastes and by products from foods
PublicationIndustries in the agro-food sector are the largest generators of waste in the world. Agro-food wastes and by products originate from the natural process of senescence, pretreatment, handling, and manufacturing processes of food and beverage products. Notably, most of the wastes are produced with the transformation of raw materials (such as fruits, vegetables, plants, tubers, cereals, and dairy products) into different processed...
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New Complementary Resonator for Permittivity- and Thickness-Based Dielectric Characterization
PublicationThe design of high-performance complementary meta-resonators for microwave sensors featur-ing high sensitivity and consistent evaluation of dielectric materials is challenging. This paper presents the design and implementation of a novel complementary resonator with high sensi-tivity for dielectric substrate characterization based on permittivity and thickness. A comple-mentary crossed arrow resonator (CCAR) is proposed and integrated...
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Satellite Laser Ranging technique as a tool for the determination of the Schwarzschild, de Sitter and Lense-Thirring effects
PublicationSatellite Laser Ranging (SLR) is a modern technique used in various research areas and applications related to geodesy and geodynamics. It is commonly used for tasks such as establishing the International Terrestrial Reference Frame (ITRF), monitoring Earth Orientation Parameters (EOP), determining the geocenter, measuring fundamental physical constants, calibrating microwave tracking techniques, conducting time transfer experiments,...
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Evaluation and rationale of the performance of several elastomeric composites incorporating devulcanized EPDM
Publicationthylene Propylene Diene rubber (EPDM), is present in many applications. However, its crosslinked structure makes difficult its recycling. The use of devulcanized EPDM, (dEPDM) as a component of elastomeric composites, is a real possibility to reuse EPDM scraps. In this study, three matrices (natural rubber (NR), styrene butadiene rubber (SBR) and EPDM rubber) have been tested including devulcanized EPDM as a recycled component....