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Wyniki wyszukiwania dla: SENSITIVITY ANALYSIS, FREE TORSIONAL VIBRATION FREQUENCIES, THIN-WALLED BEAMS, ANALYTICAL SOLUTION, FEM
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Efficiency of service recovery in scale-free optical networks under multiple node failures
PublikacjaIn this paper we examine the properties of scale-free networks in case of simultaneous failures of two networknodes. Survivability assumptions are as follows: end-to-end path protection with two node-disjoint backup pathsfor each working path. We investigate three models of scale-free networks generation: IG, PFP and BA.Simulations were to measure the lengths of active and backup paths and the values of service recovery time.We...
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Cost-Effective and Sufficiently Precise Integration Method Adapted to the FEM Calculations of Bone Tissue
PublikacjaThe technique of Young’s modulus variation in the finite element is not spread in biomechanics. Our future goal is to adapt this technique to bone tissue strength calculations. The aim of this paper is to present the necessary studies of the element’s integration method that takes into account changes in material properties. For research purposes, a virtual sample with the size and distribution of mechanical properties similar...
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Optimized conditions for hydrocarbon group type analysis of base oils by thin-layer chromatography - flame ionisation detection
PublikacjaW pracy przedstawiono wyniki badań nad opracowaniem optymalnych warunków oznaczania składu grupowego mineralnych olejów bazowych z wykorzystaniem chromatografii cienkowarstwowej oraz detektora płomieniowo-jonizacyjnego (TLC-FID). W przypadku mineralnych olejów bazowych, które otrzymywane są po wielu etapach rafinacji frakcji pochodzących z destylacji próżniowej ropy naftowej oznaczenie ich składu grupowego (z uwzględnieniem podgrup...
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Electrostatic Zipping Actuators—Analysis of the Pull-In Effect Depending on the Geometry Parameters
PublikacjaContinuous work on a new generation of actuators, referred to as artificial muscles, resulted in the initiation of work on electrostatic zipping actuators, the concept of which is derived from micro electro-mechanical devices. Despite partial knowledge of their basic operating parameters, a question remains whether electrostatic zipping actuators are able to meet the expectations in the context of generated forces and control possibilities....
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One-dimensional chaos in a system with dry friction: analytical approach
PublikacjaWe introduce a new analytical method, which allows to find chaotic regimes in non-smooth dynamical systems. A simple mechanical system consisting of a mass and a dry friction element is considered. The corresponding mathematical model is being studied. We show that the considered dynamical system is a skew product over a piecewise smooth mapping of a segment (the so-called base map). For this base map we demonstrate existence of...
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Fault Diagnostics in PEMFC Stacks by Evaluation of Local Performance and Cell Impedance Analysis
PublikacjaStarvation, flooding, and dry‐out phenomena occur in polymer electrolyte membrane fuel cells (PEMFCs), due to heterogeneous local conditions, material inhomogeneity, and uneven flow distribution across the single cell active area and in between the individual cells. The impact of the load level and air feed conditions on the performance was identified for individual single cells within a 10‐cell stack. Analysis of the current density...
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The influence of solution annealing temperature on the properties of Lean Duplex 2101 welded joints in tubes
PublikacjaThe article presents a technology of TIG longitudinal welding without filler material (142) of heat exchanger tubes made of Lean Duplex 2101. The results of studies on the effect of heat treatment (solution annealing) on tensile strength, plasticity, delta ferrite and the structure of smooth tubes are shown. It was found, that the change in solution annealing temperature across the tested range has an impact on mechanical properties...
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Review of sewage sludge management: standards, regulations and analytical methods
PublikacjaThis article presents the most popular methods of sewage sludge management and associated unit operations and processes referring to them. The most popular methods are: Reclamation and adaptation of lands to specific needs; plant cultivation not intended for consumption or for production of food; usage in agriculture; usage in building; recovery of phosphorus, rare earth metals or fats and usage in industry; producing combustible...
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Detection of delamination in multi layer composite beams.
PublikacjaW pracy przedstawiono model belki kompozytowej z delaminacją. Omówiono czynniki propagacji fali sprężystej w belce i możliwości wykorzystania zmian w propagującej fali wywołanych delaminacją do jej detekcji.
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Electronic stabilization of beams in sonar with cylindrical array
PublikacjaArtykuł prezentuje podstawy opisu beamformera dla sonaru z antena cylindryczną. Artykuł pokazuje, że zmodyfikowany beamformer może zostać użyty do stabilizacji osi wiązki w horyzontalnej płaszczyźnie, gdy znany jest przechył i zanurzenie statku. Artykuł przedstawia także problem elektronicznego odchylania wiązki.
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Deposition and Electrical and Structural Properties of La0.6Sr0.4CoO3 Thin Films for Application in High-Temperature Electrochemical Cells
PublikacjaLow-temperature deposition of electroceramic thin films allows the construction of new devices and their integration with existing large-scale fabrication methods. Developing a suitable low-cost deposition method is important to further advance the development of microdevices. In this work, we deposited a 1-lm-thick La0.6Sr0.4CoO3d (LSC) perovskite with high electrical conductivity on sapphire substrates at 400C and analyzed its...
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The Effect of Sterols on Amphotericin B Self-Aggregation in a Lipid Bilayer as Revealed by Free Energy Simulations
PublikacjaAmphotericin B (AmB) is an effective but toxic antifungal drug, known to increase the permeability of the cell membrane, presumably by assembling into transmembrane pores in a sterol-dependent manner. The aggregation of AmB molecules in a phospholipid bilayer is, thus, crucial for the drug’s activity. To provide an insight into the molecular nature of this process, here, we report an atomistic molecular dynamics simulation study...
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What matters most to patients? On the Core Determinants of Patient Experience from Free Text Feedback
PublikacjaFree-text feedback from patients is increasingly used for improving the quality of healthcare services and systems. A major reason for the growing interest in harnessing free-text feedback is the belief that it provides richer information about what patients want and care about. The use of computational approaches such as structural topic modelling for analysing large unstructured textual data such as free-text feedback from patients...
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Direct modulation for conventional matrix converters using analytical signals and barycentric coordinates
PublikacjaThis paper proposes the generalized direct modulation for Conventional Matrix Converters (CMC) using the concept of analytical signals and barycentric coordinates. The paper proposes a novel approach to the Pulse Width Modulation (PWM) duty cycle computing, which allows faster prototyping of direct control algorithms. The explanation of the new idea using analytical considerations demonstrating the principles of direct voltage...
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Novel analytical method for detection of orange juice adulteration based on ultra-fast gas chromatography
PublikacjaThe food authenticity assessment is an increasingly important issue in food quality and safety. The application of an electronic nose based on ultra-fast gas chromatography technique enables rapid analysis of the volatile compounds from food samples. Due to the fact that this technique provides chemical profiling of natural products, it can be a powerful tool for authentication in combination with chemometrics. In this article,...
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Production of gaseous matrix-free reference materials. Application of thermoanalytical techniques
PublikacjaMateriały odniesienia są wykorzystywane w każdym laboratorium w celu zapewnienia jakości wyników pomiarów analitycznych. Produkcja materiałów odniesienia nie jest zadaniem łatwym, szczególnie w przypadku składników gazowych, toksycznych i o nieprzyjemnym zapachu. Termiczny rozkład związków powierzchniowych jest bardzo dogodnym sposobem sporządzania właśnie tego rodzaju mieszanin. Ważną rolę w procesie termicznego rozkładu związków...
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Free convection of water-Al2O3 nanofluid from horizontal porous coated tube
PublikacjaNanofluids are expected to enhance heat transfer in many thermal systems. Present efforts are concentrated on boiling heat transfer of nanofluids, although single phase convection is of key importance in various appliances such as car radiators or heating systems. This paper presents experimental results of heat transfer during free convection of water-Al3O3 nanofluid from horizontal tube covered with metallic porous coating. Contrary...
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The use of fibre-reinforced polymers (FRP) in bridges as a favourable solution for the environment
PublikacjaThe purpose of this article is to show the modern engineering, in which sustainability and taking care of ecology play a significant role. The authors are focused on FRP composite materials and their applications in civil engineering. Case studies showing renovation and design of new bridges with the use of FRP are presented and discussed to clarify benefits, which this solution provides. Main advantages of FRP materials in comparison...
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On the Nonlinear Effects of Magnetoacoustic Perturbations in Optically Thin Quasi-Isentropic Plasmas
PublikacjaNonlinear effects of planar magnetosound perturbations in a plasma are discussed. Plasma is non-adiabatic due to optically thin radiation and external heating. For these reasons, thermal instability of a plasma may appear which makes it acoustically active. The plasma is assumed to be initially homogeneous ideal gas with infinite electrical conductivity permeated by a straight magnetic field which is orthogonal to the trajectories...
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Application of Thin ZnO ALD Layers in Fiber-Optic Fabry-Pérot Sensing Interferometers
PublikacjaIn this paper we investigated the response of a fiber-optic Fabry-Pérot sensing interferometer with thin ZnO layers deposited on the end faces of the optical fibers forming the cavity. Standard telecommunication single-mode optical fiber (SMF-28) segments were used with the thin ZnO layers deposited by Atomic Layer Deposition (ALD). Measurements were performed with the interferometer illuminated by two broadband sources operating...
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Solvent-Free Synthesis of Phosphonic Graphene Derivative and Its Application in Mercury Ions Adsorption
PublikacjaFunctionalized graphene was efficiently prepared through ball-milling of graphite in the presence of dry ice. In this way, oxygen functional groups were introduced into material. The material was further chemically functionalized to produce graphene derivative with phosphonic groups. The obtained materials were characterized by spectroscopic and microscopic methods, along with thermogravimetric analysis. The newly developed material...
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Analysis of pesticide residue in tomato samples using analytical protocol based on application of QuEChERS technique and GC-ECD system
PublikacjaQuEChERS sample preparation method was used for the determination of 10 pesticides and their metabolites in tomato samples, coupled to gas chromatography with electron capture detector (GCECD). The experimental parameters including oven temperature program, amount of the sample and purifying agent were optimized. The GC-ECD method was validated in terms of linearity, selectivity and recovery. The limits of detection (LODs) of the...
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Thermal analysis and experimental verification of permanent magnet synchronous motor by combining lumped-parameter thermal networks with analytical method
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Recent developments and future trends in solid phase microextraction techniques towards green analytical chemistry
PublikacjaSolid phase microextraction find increasing applications in the sample preparation step before chromatographic determination of analytes in samples with a complex composition. These techniques allow for integrating several operations, such as sample collection, extraction, analyte enrichment above the detection limit of a given measuring instrument and the isolation of analytes from sample matrix. In this work the information about...
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Effect of multi-walled carbon nanotubes properties on the photocatalytic activity of bismuth-based composites synthesised via an imidazolium ionic liquid
PublikacjaThe use of various types of multi-walled carbon nanotubes in the synthesis of bismuth oxybromide semiconductors via imidazolium ionic liquid was studied in detail. The effect of the MWCNT shape, specific surface area, and various diameters on the morphology, surface properties and photoactivity of the Bi-based composites has been investigated for the first time. So far, the literature has only shown the enhancement of photocatalytic...
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A non-quasi-static small-signal model of the four-terminal MOSFET for radio and microwave frequencies.
PublikacjaW pracy zaprezentowano nowy małosygnałowy model tranzystora MOS, w którymuwzględnia się efekt nasycenia prędkości nośników. Model jest spójny fizycznie i może być stosowany w analizie dowolnej konfiguracji włączenia tranzystora.
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Theoretical study of the structure, energetics and vibrational frequencies of water-acetone and water-2-butanone complexes
PublikacjaKompleksy acetonu i 2-butanonu z 0-2 cząsteczkami wody połączonymi wiązaniem wodorowym z tlenem karbonylowym zbadano z wykorzystaniem teorii funkcjonału gęstości (DFT) na poziomie B3LYP/6-311++G(d,p). Obliczenia w fazie gazowej uzupełniono o optymalizacje w otoczeniu rozpuszczalnika, symulowanego za pomocą modelu polaryzowalnego kontinuum (PCM). Częstości drgań oscylacyjnych otrzymane na podstawie zależności empirycznej sa zgodne...
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25 kV–50 Hz railway supply modelling for medium frequencies (0–5 kHz)
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Modulation of dielectric properties in low-loss polypropylene-based composites at GHz frequencies: theory and experiment
PublikacjaPolymer composites with high dielectric constant and low loss tangent are highly regarded as substrates for modern high-speed electronics. In this work, we analyze the high-frequency dielectric properties of two types of composites based on polypropylene infused with high-dielectric-constant microparticles. Two types of fillers are used: commercial ceramics or titanium oxide ( TiO2) with different concentrations. The key observation...
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Some theoretical models of technical woven fabric and their use in FEM.
PublikacjaCelem pracy było przedstawienie niektórych typów równań konstytutywnych opisujących zachowanie powłok membranowych używanych do konstrukcji przekryć wiszących. Ocena zastosowanego modelu izotropowego i sieci gęstej w analizie tkanin technicznych. Dokonano porównania wyników uzyskanych własnymi algorytmami metody elementów skończonych z powszechnie dostępnym na rynku programem komercyjnym MARC firmy MSC. Uzyskano dobrą zgodność...
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FEM modeling of structures based on close range digital photogrammetry
PublikacjaPraca dotyczy metodologii przygotowania modelu konstrukcji istniejącej do analizy mechanicznej metodą element ow skończonych. MOdelowanie geometrii budowli jest oparte na danych pozyskanych z pomiarów fotogrametrycznych. Praca wskazuje na możliwości oraz efektywność zastosowania metod optometrycznych w rewitalizacji budowli zabytkowych, an przykładzie modelu dachu drewnianego.
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VOF-DEM-FEM combined model of the reef breakwater collapse
PublikacjaZespolony model numeryczny (metoda modelowania przepływu ze swobodną powierzchnią rozdziału faz ciekłej i gazowej w siatce nieruchomej (ang. Volume of Fluid - VOF, metoda elementów dyskretnych (ang. Distinct Element Method, metoda elementów skończonych (MES)) został wykorzystany do zbadania odkształceń falochronu narzutowego i jego piaszczystego podłoża w wyniku oddziaływania falowania powierzchniowego. Wyniki analizy numerycznej...
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On the FEM implementation of the large rotation shell theory for elasticanisotropic shells.
PublikacjaW pracy przedstawiono problemy implementacji MES teorii powłok o dużych obrotach w statycznej, geometrycznie nieliniowej analizie konstrukcji warstwowych. Zwrócono uwagę na właściwą interpretacje rotacyjnych stopni swobody w algorytmie MES. Omówiono wariant dużych i skończonych obrotów. Przedstawiono wyniki obliczeń dla znanego w literaturze przykładu analizy paneli kompozytowej w zakresie dużych obrotów.
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Analytical progress on symmetric geometric discord: Measurement-based upper bounds
PublikacjaQuantum correlations may be measured by means of the distance of the state to the subclass ofstates having well defined classical properties. In particular, a geometric measure of asymmetricdiscord [Daki´c et al., Phys. Rev. Lett. 105, 190502 (2010)] was recently defined as the Hilbert-Schmidt distance of a given two-qubit state to the closest classical-quantum (CQ) correlated state.We analyze a geometric measure of symmetric...
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The sensitivity of bacteria to heavy metals in presence of mineral ship motor oil in coastal marine sediments and waters.
PublikacjaThe sensitivity of bacteria, isolated from coastal marine sediments and waters of Sopot beach, Gdańsk Bay (Poland), to heavy metals in the presence of mineral ship motor oil were studied. All isolated heterotrophic bacteria were resistant to the 0.1 mM lead concentration occurring in the environment. Metal resistance of bacteria isolated from coastal water was strongly related to mineral ship motor oil concentration. At 0.1% mineral...
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O obliczaniu kablobetonowych ciągłych dźwigarów mostowych
PublikacjaPrzedstawiono analityczną metodę obliczania kablobetonowych ciągłych dźwigarów z wykorzystaniem metody sił. Podano przykład analizy zrealizowanego kablobetonowego wiaduktu o schemacie dwuprzęsłowej belki ciągłej. Porównano wyniki obliczeń analitycznych i numerycznych (model belkowy, program Sofistik).
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Application of thin diamond films in low-coherence fiber-optic Fabry Pérot displacement sensor
PublikacjaThe novel fiber-optic low coherence sensor with thin diamond films is demonstrated. The undoped and boron-doped diamond films were elaborated by the use of the microwave plasma enhanced chemical vapor deposition (μPE CVD) system. The optical signal from the Fabry–Pérot cavity made with the application of those thin films is sensitive to displacement. The sensor characterization was made in the range of 0–600 μm. The measurements...
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Compressed Projection Bases for Model-Order Reduction of Multiport Microwave Components Using FEM
PublikacjaThis paper presents a projection basis compression technique for generating compact reduced-order models (ROM) in the FE analysis of microwave devices. In this approach redundancy is removed from the projection basis by means of the proper orthogonal decomposition technique applied to the projected system of linear equations. Compression allows for keeping the size of a reduced-order model as small as possible without compromising...
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Green analytical chemistry in sample preparation for determination of trace organic pollutants
PublikacjaW pracy przedstawiono przyjazne środowisku techniki analityczne, stosowane w celu izolacji i wzbogacania analitów. Ilość używanych rozpuszczalników jest ograniczana przez stosowanie alternatwnych rozpuszczalników, technik bezrozpuszczalnikowych, ekstrakcji wspomaganych czynnikami zewnętrznymi oraz przez wprowadzanie mikrosystemów analitycznych.
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Analytical techniques in studies of the environmental fate of pharmaceuticals and personal-care products
PublikacjaW pracy przedstawiono dane literaturowe odnośnie źródeł emisji, dróg transportu, przemian i metabolizmu, pomiomu stężeń ksenobiotyków z grupy farmaceutyków i środków higieny osobistej w próbkach pobranych z różnych elementów środowiska (woda, gleba, osady denne) oraz próbek bioty. Szczególną uwagę zwrócono na techniki analityczne wykorzystywane w badaniach losu środowiskowego w/w zanieczyszczeń.
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Analytical procedures for PAH and PCB determination in water samples - error sources
PublikacjaW pracy przedstawiono poszczególne etapy procedury analitycznej wykorzystywanej do oznaczania analitów z grupy WWA i PCB w próbkach wody. Pokazano jakie problemy występują podczas oznaczania wyżej wymienionych analitów i jaki mogą mieć wpływ na końcowy wynik analizy.
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COMMENTS ON EXISTING ANALYTICAL SOLUTIONS TO THE WAVE-INDUCED CYCLIC RESPONSE OF A POROUS SEABED OF INFINITE THICKNESS
PublikacjaThis paper deals with the wave-induced cyclic response of a porous seabed (by means of oscillating parameters: pore-fluid pressure, soil displacement components, effective normal stress and shear stress components) due to a surface sinusoidal water-wave propagating over a seabed of infinite thickness. The main existing analytical solutions to the governing problem are critically discussed, pointing out their meaningful errors and...
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Electronic structure and magnetism of samarium and neodymium adatoms on free-standing graphene
PublikacjaThe electronic structure of selected rare-earth atoms adsorbed on a free-standing graphene was investigated using methods beyond the conventional density functional theory (DFT+U, DFT +HIA, and DFT+ED). The influence of the electron correlations and the spin-orbit coupling on the magnetic properties has been examined. The DFT+U method predicts both atoms to carry local magnetic moments (spin and orbital) contrary to a nonmagnetic...
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Characterization of Optical and Electrical Properties of Transparent Conductive Boron-Doped Diamond thin Films Grown on Fused Silica
PublikacjaA 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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Wykorzystaniem metody elementów skończonych w obliczaniu stateczności silosu z blachy falistej = Finite element method in determining stability of with corrugated walls strengthened by vertical columns of thin walled open cross section
PublikacjaGwałtowny rozwój zastosowania MES w działalności inżynierskiej nastąpił w połowie lat osiemdziesiątych w związku z pojawieniem się komputerów osobistych (PC), na które przeniesione zostały programy z dużych jednostek obliczeniowych. W ten sposób efektywne narzędzie rozwiązywania problemów analiz i projektowania jakim jest MES, stało się powszechnie dostępne. W artykule przedstawiono zastosowanie MES w analizie stateczności stalowego...
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Nickel Oxide Thin Film Sensor for Fluctuation-Enhanced Gas Sensing of Formaldehyde
PublikacjaNanocrystalline nickel-oxide-based thin films were prepared by advanced reactive gas deposition, and the response of these films to formaldehyde was studied by fluctuationenhanced sensing. Morphological and structural analyses showed porous deposits of nickel oxide particles with face-centered cubic structure. Resistance fluctuations were measured upon exposure to ethanol, formaldehyde and methane at 200 °C. Power density spectra...
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Experimental investigation of free convection of glycol-Al2O3 nanofluid from horizontal tube
PublikacjaNanofluids came to be seen as a new generation of coolants, both in single- and two phase systems. Furthermore, nanofluids or nanocomposites may be used as a media in a thermal energy storage (TES) in such systems as sensible heat storage (SHS) and phase change materials (PCM). In the SHS systems the dominating mechanism of the heat transfer is natural convection. However, in the literature only a few investigations of free convection...
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EXPERIMENTAL INVESTIGATION OF FREE CONVECTION OF GLYCOL-Al2O3 NANOFLUID FROM HORIZONTAL TUBE
PublikacjaNanofluids came to be seen as a new generation of coolants, both in single- and two phase systems. Furthermore, nanofluids or nanocomposites may be used as a media in a thermal energy storage (TES) in such systems as sensible heat storage (SHS) and phase change materials (PCM). In the SHS systems the dominating mechanism of the heat transfer is natural convection. However, in the literature only a few investigations of free convection...
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Influence of plasmon resonance on the luminescence of titanium dioxide thin films doped with rare earth ions
PublikacjaIn this work the study of the optical properties of europium doped titanium dioxide thin films (TiO2:Eu) enhanced by gold plasmonic nanostructures are presented. Plasmonic platforms were manufactured by thermal annealing of thin film of Au, deposited on a Corning glass substrate. As a result of thermal treatment, gold spherical nanostructures with average dimensions of 50 nm were obtained. Luminescent TiO2:Eu film was deposited...
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Metals and metal-binding ligands in wine: Analytical challenges in identification.
PublikacjaBackground Due to important role of metals in the vinification process as well as their impact on the human health, their content in this alcoholic beverage has been extensively studied by many researchers. It is already known that speciation of metals determines their toxicity and bioavailability as well as influences their activity. Understanding the chemistry and knowing the structures of metal complexes could have relevant...