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Wyniki wyszukiwania dla: ceramics,lanthanum orthoniobate,lanthanum orthoarsenate,co-precipitation,solid state synthesis
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Cation sensing by diphenyl-azobenzocrowns
PublikacjaMetal cations complexation and proton binding by 13- and 16-membered diphenyl-azobenzocrowns and diphenyl-hydroxyazobenzocrowns were studied in acetonitrile using spectroscopic methods: UV–vis spectroscopy, spectrofluorimetry, and 1H NMR spectroscopy. Phenyl moieties in benzene rings were found to affect binding strength alkali and alkaline earth metal cations and hydrogen ion, and affect tautomeric equilibrium of hydroxyazobenzocrowns....
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Mössbauer Spectroscopy and Magnetoelectric Effect Studies of Multiferroic Ceramics Based on BiFeO<sub>3</sub>
PublikacjaIn this work the results of investigations for (BiFeO3)x(BaTiO3)1-x and Bi1-xNdxFeO3 solid solutions are described. Samples were prepared by the conventional solid-state sintering method. X-ray diffraction, 57Fe Mössbauer spectroscopy, and magnetoelectric effect measurements were applied as complementary methods to determine the structure and magnetic properties of materials. For (BiFeO3)x(BaTiO3)1-x solid solutions Mössbauer...
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Toward Polyethylene–Polyester Block and Graft Copolymers with Tunable Polarity
PublikacjaThe synthesis and characterization of polyethylene–polyester block and graft copolymers and their potential as compatibilizers in polyethylene-based polymer blends are being described. The various routes to functionalized polyethylenes and the corresponding block/graft copolymers have been compared and evaluated for their scalability to industrial scale production. Hydroxyl chain-end and randomly OH-functionalized HDPE as well...
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π-Stacking attraction vs. electrostatic repulsion: competing supramolecular interactions in a tpphz-bridged Ru(ii)/Au(iii) complex
PublikacjaThe synthesis and characterization of a mixed metal ruthenium(II)/gold(III) complex bridged by tetrapyridophenazine (tpphz) are described. It is isostructural and isoelectronic to the well-known photocatalysts with palladium(II) or platinum(II). Concentration dependent 1H-NMR spectroscopy and XRD studies show that the electrostatic repulsion between the gold(III) moieties exceeds the attractive π-stacking interaction. Theoretical...
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Multivariate Assessment of Procedures for Molecularly Imprinted Polymer Synthesis for Pesticides Determination in Environmental and Agricultural Samples
PublikacjaIn the case of quantitative and qualitative analysis of pesticides in environmental and food samples, it is required to perform a sample pre-treatment process. It allows to minimalize the impact of interferences on the final results, as well as increase the recovery rate. Nowadays, apart from routinely employed sample preparation techniques such as solid-phase extraction (SPE) or solid-phase microextraction (SPME), the application...
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Reactions of Lithiated Diphosphanes R2P−P(SiMe3)Li (R = tBu and iPr) with [MeNacnacTiCl2·THF] and [MeNacnacTiCl3]. Formation and Structure of TitaniumIII and TitaniumIV β‑Diketiminato Complexes Bearing the Side-on Phosphanylphosphido and Phosphanylphosphinidene Functionalities
Publikacjaβ-Diketiminate complexes of TiIII-containing phosphanylphosphido ligands [MeNacnacTi(Cl){η2-P(SiMe3)- PR2}] (MeNacnac− = [Ar]NC(Me)CHC(Me)N[Ar]; Ar = 2,6- iPr2C6H3) were prepared by reactions of [MeNacnacTiCl2· THF] with lithium derivatives of diphosphanes R2P−P(SiMe3) Li (R = tBu, iPr) in toluene solutions. Surprisingly, reactions of [MeNacnacTiCl2·THF] with R2P−P(SiMe3)Li in THF solutions led to TiIV complexes containing phosphanylphosphinidene ligands...
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The domination of ionic conductivity in tetragonal phase of the organometal halide perovskite CH3NH3PbI3-xClx
PublikacjaOrganometal trihalide perovskites have recently gained extreme attention due to their high solar energy conversion in photovoltaic cells. Here, we investigate the contribution of iodide ions to a total conductivity of the mixed lead halide perovskite CH3NH3PbI3−xClx with a use of the modified DC Hebb–Wagner polarization method. It has been identified that an ionic conductivity dominates in tetragonal phase which is associated with room...
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Electrical properties of Na2O-CaO-P2O5 glasses doped with SiO2 and Si3N4
PublikacjaSodium-calcium-phosphate glasses doped with SiO2 or Si3N4 having similar sodium ion concentrations were prepared by melt quenching. The conductivity was measured by impedance spectroscopy under nitrogen atmosphere in a wide frequency range (10 mHz–1 MHz) and wide temperature range (153–473 K). At 36.6 °C, DC conductivities of all glasses vary between 1.1 ∗ 10−12 and 8.9 ∗ 10−12 S cm−1 and have similar activation energies (between...
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Ion conduction in beryllium-alumino-silicate glasses doped with sodium or sodium and lithium ions
PublikacjaElectrical properties of beryllium-alumino-silicate glasses containing sodium ions or sodium and lithium ions were studied with impedance spectroscopy technique over a frequency range from 10 mHz to 1 MHz and at temperature range from 213 to 473 K. The frequency- and temperature-dependent conductivity spectra of individual single alkali glasses were superimposed by means of the Summerfield scaling. Mixed-alkali glasses do not overlap...
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Analysis of Ceramic Elements with Ring-Crack Defects in Lubricated Rolling Contact
PublikacjaThe properties of ceramics, specifically low density, high hardness, high temperature capability and low coefficient of thermal expansion are of most interest to rolling element manufacturers. Surface ring cracks on lubricating rolling contact fatigue failure has been studied using numerical fracture analysis. Such cracks are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculations...
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Electrodes consisting of PEDOT modified by Prussian Blue analogues deposited onto titania nanotubes – Their highly improved capacitance
PublikacjaIn this work we present the outstanding energy storage of prepared inorganic-organic heterojunction where hydrogenated ordered titania nanotubes (H-TiO2NT) were modified by the hybrid made of poly(3,4-ethylenedioxythiophene) (pEDOT) and iron hexacyanoferrate centres (Fehcf, Prussian Blue). The material TiO2NT/pEDOT:Fechf was obtained electrochemically by means of: anodization, hydrogenation and finally, electropolymerization of...
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Flexible dye-sensitized solar cells based on Ti/TiO2 nanotubes photoanode and Pt-free and TCO-free counter electrode system
PublikacjaFlexible dye-sensitized solar cells (DSSCs) are getting more attention compared to standard glass covered DSSCs due to their unique commercial applications (e.g. tents or sail surfaces) and the possibility of rolling up into a small, portable device. In this work, titania nanotubes (TiO2 NT) modified with titania nanoparticles (TiO2 NP) were photoelectrochemically characterized as an anode for flexible dye-sensitized solar cells....
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Electrochemical performance of Co3O4/CeO2 electrodes in H2S/H2O atmospheres in a proton-conducting ceramic symmetrical cell with BaZr0.7Ce0.2Y0.1O3 solid electrolyte
PublikacjaThe electrochemical performance of Co3O4/CeO2 mixed oxide materials as electrodes, when exposed to H2S/H2O atmospheres, was examined employing a proton conducting symmetrical cell, with BaZr0.7Ce0.2Y0.1O3 (BZCY72) as the solid electrolyte. The impact of temperature (700–850 °C) and H2S concentration (0–1 v/v%) in steam-rich atmospheres (90 v/v% H2O) on the overall cell performance was thoroughly assessed by means of electrochemical...
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Synthesis and structural properties of (Y, Sr)(Ti, Fe, Nb)O3−δ perovskite nanoparticles fabricated by modified polymer precursor method
PublikacjaThe yttrium, iron and niobium doped-SrTiO3 powders have been successfully fabricated by a modified low–temperature synthesis method from a polymer complex. The usage of strontium hydroxide precursor instead of conventional strontium nitrate or strontium carbonate provides to the possibility of significant decrease of annealing temperature. It allows to prepare a material with sphere-shape grains of nanometric size (15–70 nm). The...
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Identification of Kinematic Excitation Function by the Modal Coordinates Estimation of the System's Dynamics
PublikacjaThe paper presents a method of the kinematic excitation courses’ identification in excitation points, based on the car road test acceleration at different measurement points. For the purpose of the laboratory fatigue life investigation of contemporary complex structures (e.g. cars bodies) and components of these structures (i.e. cars roofs), only a few first vibration modes are usually taken into account. During real life tests...
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CGO as a barrier layer between LSCF electrodes and YSZ electrolyte fabricated by spray pyrolysis for solid oxide fuel cells
PublikacjaPerovskite La0.6Sr0.4Co0.2Fe0.8O3 − δ (LSCF) is often used as a cathode material for solid oxide fuel cells (SOFC) due to high mixed ionic and electronic conductivity and good catalytic activity. Unfortunately, sintering of the LSCF cathode together with the yttria stabilized zirconia (YSZ) electrolyte, leads to formation of the La2Zr2O7 and SrZrO3 phases in the interface. These phases increase the resistance of the cell. To avoid...
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Two kinds of oxygen vacancies in lithium titaniate doped with copper as detected by EPR
PublikacjaLithium titanate (Li1+xTi2-xO4) doped with Cu2+ ions was synthesized by sol-gel processing method. The structure and morphology are characterized by X-ray Diffraction (XRD), X-ray Photoemission Spectroscopy (XPS), Scanning Electron Microscopy (SEM) and Electron Paramagnetic Resonance (EPR). Spin Hamiltonian parameters describing Zeeman and hyperfine interaction for 63Cu2+ ions were obtained from EPR spectra simulations. The spectra...
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Enhanced trap-assisted recombination in organic semiconductors
PublikacjaAn analytical model to describe the interaction of excitons and charge transfer states with deep traps is formulated for the case of molecular materials. Here, we have considered the influence of a trap-assisted recombination on this phenomenon. The final expression for the effective recombination rate has been derived from the Shockley–Read–Hall theory and kinetic equations which characterize different photophysical processes....
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The σ-phase superconductors Nb20.4Rh5.7Ge3.9 and Nb20.4Rh5.7Si3.9
PublikacjaWe show that the previously unreported ternary σ phases Nb20.4Rh5.7Ge3.9 and Nb20.4Rh5.7Si3.9 are both superconductors with Tc values of approximately 1.9 K. The superconducting transitions were characterized through temperature-dependent magnetic susceptibility, electrical resistance, and specific heat measurements. The Sommerfeld constants, γ, for Nb20.4Rh5.7Ge3.9 and Nb20.4Rh5.7Si3.9 are 89(1) mJ mol-f.u.−1K−2 and 86(1) mJ mol-f.u.−1K−2...
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Copper and cobalt co-doped ceria as an anode catalyst for DIR-SOFCs fueled by biogas
PublikacjaThe nanocrystalline compounds of Co and Cu co-doped ceria (with up to 20 mol.% of dopants) were fabricated by the reverse microemulsion synthesis method. They were deposited in a form of layers on the surface of SOFC anode in an aim to act as electrochemically active materials for biogas reforming process. Fourier Transformed Infrared Spectroscopy was used to analyze a composition of outlet gases simultaneously with the tests of...
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Nonlinear electrical properties of glass-ceramics nanocomposites containing ferroelectric nanocrystallites of Bi2VO5.5
PublikacjaNonlinear A.C. impedance measurements were conducted in the 50BiV-50SrBAlO nanocomposite as a function of frequency, temperature and A.C. voltage. This material is ferroelectric below temperature of 730 K, and above 730 K is a good ion-conductor. For this nanocomposite a low A.C. voltage of 1 V rms is enough to observe high nonlinearities. The origin of these nonlinear effects depends on the temperature and frequency. In the high...
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Synthesis and properties of porous Sr 0.96 Y 0.04 Ti 1−x Nb x O 3
PublikacjaA series of porous, single phase Sr0.96Y0.04Ti1-xNbxO3 samples was obtained using a wet synthesis method (modified citrate sol-gel) method. Temperature-programmed reduction (TPR) and temperature-programmed oxidation (TPO) measurements have shown high stability of the obtained material in variable (oxidizing/reducing) atmospheres. All samples exhibit high conductivity in hydrogen atmosphere with the highest value (around 1S/cm)...
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Structure and electrical properties of Y, Fe-based perovskite mixed conducting composites fabricated by a modified polymer precursor method
PublikacjaIn this work, samples of Y0.07Sr0.93Ti1-xFexO3-d with 20, 40, 60 and 80 mol% of iron amount were prepared by a low-temperature polymer precursor method. The SEM-EDS analysis proved that analyzed Y0.07Sr0.93Ti1-xFexO3-d samples were composites of two Ti- and Fe-rich perovskite samples. This kind of composite consists of two phases in which one has a good ionic and the other electronic conductivity, which makes such a composite a...
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Preparation and photocatalytic properties of BaZrO 3 and SrZrO 3 modified with Cu 2 O/Bi 2 O 3 quantum dots
PublikacjaIn this study, we report a novel method of BaZrO3 and SrZrO3 surface modification by two different types of quantum dots (QDs, Cu2O and Bi2O3), which improved the photocatalytic performance of the obtained materials under UV-Vis light irradiation. Pristine BaZrO3 and SrZrO3 were prepared by the hydrothermal method. The deposition of Cu2O- and Bi2O3-QDs was carried out by chemical reduction. The morphology of the nanoparticles was...
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Structure and thermoelectric properties of Cs-Bi-Te alloys fabricated by different routes of reduction of oxide reagents
PublikacjaCesium-bismuth-telluride polycrystalline materials were fabricated using a cost-effective method based on a reduction of oxide reagents, leading to a production of a material with good thermoelectric properties. Several samples with various initial stoichiometry were prepared by melting of oxide powders at 1050 °C, quenching, milling to powders and then reducing in pure hydrogen at 400 °C. Another concept was to obtain the CsBi4Te6...
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Electronic conductivity in the SiO2–PbO–Fe2O3 glass containing magnetic nanostructures
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Electrical properties and structure of lead-borate glass containing iron ions
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Multi Parameter Sliding Test Result Evaluation for the Selection of Material Pair for Wear Resistant Components of a Hydraulic Motor Dedicated for Use with Environmentally Friendly Working Fluids
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Degradation of Gel-Coat Layer in Glass/Polyester Laminate in Seawater Environment
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Magnetic properties of charge ordered complex TCNQ salts with lattice distortions
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Low-temperature reactivity of the surface species of vanadia–tungsta catalyst
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Magnetic properties of Co/Pd multilayered films on porous Al2O3 templates with developed cell substructure
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Energy-Saving Mechatronic System for Fatigue Tests of Materials under Variable-Amplitude Proportional Bending and Torsion
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A Noded Carbon Emission Tool (NCET) to Measure Embodied Carbon (EC) in Compositional Cementitious Materials
PublikacjaThe ever evolving modern construction industry is now producing the highest levels of carbon content adversely affecting the construction associated environment. Although, the impact of carbon induced emission is quite large, but still not enough measurable standards and tools to scale these emission are available. This study contributes to the body of knowledge by providing a Grasshopper based definition to calculate the embodied...
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Impedance spectroscopy studies on hybrid materials consisting of poly(3,4-ethylenedioxythiophene) and iron, cobalt and nickel hexacyanoferrate
PublikacjaBadania warstw polimeru pEDOT modyfikowanego heksacyjanożelazianami żelaza, kobaltu i niklu przeprowadzono za pomocą spektroskopii impedancyjnej (SI). Wykazano, że materiały hybrydowe charakteryzują się dobrą stabilnością. Warstwy testowano w zakresie temperatur od 283 do 313K. w kontakcie z wodnym roztworem KCl. Wysokie współczynniki dyfuzji wskazują na możliwości wykorzystania układów jako przewodników jonowych.
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Assessment of FSW Welds Made of Aluminum Alloy AW7075-T651.
PublikacjaThis paper summarizes the results of experimental studies in which the aluminum alloy AW7075-T651 was friction stir welded (FSW) using various combinations of process parameters (rotational - R and travel speed - T). Mechanical properties of the test welds were assessed by using static tensile test and Vickers hardness measurement. The temperature of the welded plates was monitored during welding by means of thermocouples placed...
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The Characteristic of Surface Layers on Austenitic Stainless SteelAfter Glow-discharge Nitriding Process.
PublikacjaThis paper presents investigation of surface layers. The diffusion layers were produced by using different parameters of reactive atmosphere (N2:H2). The research of the surface layers was performed using scanning electron microscope (SEM). The results of energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD) analysis are presented. Research reveals the influence of chemical constitution of reactive atmosphere on the...
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The Effect Fabrication Method of Cobalt Base Clad Layer On Air Oxidation
PublikacjaNapawane warstwy ze stopu kobaltu zostały wykonane za pomocą napawania plazmowego (PTA) oraz laserowego. Zostały one poddane utlenia niu w temperarurze 1100 stopni celsiusza prze 200 godzin. Przeprowadzono badania mikrostruktury i składu chemicznego warstwy tlenkowej oraz głębszych warstw napoiny. Nie stwierdzono wpływu metody wytwarzania na skutki procesu utleniania.
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Simulation and Experiments of High Speed Machining Vibration Monitoring with Variable Spindle Velocity
PublikacjaArtykuł poświęcony jest nadzorowaniu drgań wirujących narzędzi podczas obróbki szybkościowej na nowoczesnych centrach frezarskich. Przeprowadzono analizę dynamiki procesu skrawania smukłym frezem kulistym. W celu zredukowania drgań zastosowano, z powodzeniem, zmienną prędkość obrotową narzędzia. Badania symulacyjne dotyczące efektywności proponowanej metody zostały potwierdzone wynikami badań eksperymentlanych na frezarce Alcera...
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Application of Syntactic Pattern Recognition Approach in Design and Optimisation of Group Machining Systems
PublikacjaRozwinięto koncepcję budowy zoptymalizowanych struktur systemów wytwarzania grupowego spektrum części z wykorzystaniem modelu analizy syntaktycznej sekwencji operacji ich procesów technologicznych. Określono formułę metryki odległościowej opisu stopnia zróżnicowania marszrut indywidualnych procesów oraz testowano jej skuteczność w aspekcie eksploracji wielowymiarowych danych i klasteryzacji obiektów wg cech wymagań technologicznych....
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Cobalt Base Clad Layer Resistance On The Corrosion Under Low Sulfur Preassure
PublikacjaNapawane laserowo warstwy ze stopu kobaltu, zostały poddane siarkowaniu przy niskich ciśnieniach cząstkowych w temperaturze 800 stopni celsiusza prze 24 godziny. Uzyskano warstwę zgorzeliny zróżnicowaną w zależności od zastosowanego ciśnienia. W obu jednak przypadkach podobne były zmiany zachodzące w warstwie po zgorzeliną - degradacja węglików i intensywna korozja wzdłuż granic dendrytów.
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Influence of cavitation intensity on the relative cavitation resistance of laser processed C45 carbon steel
PublikacjaPraca przedstawia badania względnej odporności kawitacyjnej we wstępnym okresie niszczenia laserowo przetopionej 6 kW laserem CO2 stali C45. Badania odporności kawitacyjnej wykonano na stanowisku z wirującą tarczą. Na erodowanej przetopionej warstwie powierzchniowej określono trzy obszary o różnej intensywności oddziaływania obciążeń kawitacyjnych. Określano wielkość odkształceń plastycznych w analizowanych obszarach, spowodowanych...
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Cavitation Erosion Resistance of Austenitic Microstructure Created byLaser Beam
PublikacjaPraca przedstawia własności kawitacyjne różnych mikfrostruktur austenitycznych tworzonych za pomocą wiązki lasera na stalach X5CrNi18-10 oraz C45. Stal X5CrNi18-10 była laserowo stopowana węglikiem TiC oraz stopowana Ni, Mn, Cr i Nb. Jako żródło mocy stosowany był laser CO2. Własności kawitacyjne oceniane były na stanowisku z wirującą tarczą. Badania ujawniły różną podatność struktury austenicycznej do odkształceń plastycznych...
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Generation of Optimal Process Plan Alternatives for ManufacturingMechanical Components
PublikacjaOmówiono aktualny stan wiedzy dotyczący wykorzystania systemów komputerowo wspomaganego projektowania procesów technologicznych - CAPP. Przedstawiono problemy związane z integracją systemów CAPP z systemami CAD. Omówiono założenia dla generowania optymalnych wariantów procesów wytwarzania z zastosowaniem modułów technologicznych tzw. features, wg metody gałęzi i ograniczceń (ang. branch-and-bound).
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Limb/Ground Impacts and Unexpected Impacts Control Strategy for a Model of a Limb of a Walking Robot
PublikacjaPraca prezentuje wyniki analizy numerycznej dynamiki robota kroczącego. Uwaga skoncentrowana jest na zagadnieniu kontaktu odnóża z podłożem. W kierunku normalnym kontakt opisano więzami jednostronnymi. W kierunku stycznym, założono obecność poślizgu i tarcia. Z uwagi na jednostronność kontaktu, może się on rozpocząć z niezerową prędkością względną. Z chwila rozpoczęcia kontaktu, prędkości zmieniają się gwałtownie. Towarzysza temu...
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Rigid Finite Element Modeling for Identification of Vibrations in Elastic in Elastic Rod Driven by a DC-motor Suplied from a Thyristor Rectifier
PublikacjaRozdział dotyczy analizy numerycznej układu elektromechanicznego. Układ składa się z silnika zasilanego z jednopołówkowego prostownika tysystorowego i napędzanego tym silnikiem wirującego pręta. Celem obliczeń jest określenie postaci i wielkości drgań pręta, jeśli uwzględniamy jego elastyczność. Dyskretna struktura modelu to łańcuch wielomasowy ciał - sztywnych ciał połączonych bezmasowymi węzłami. Autorzy obliczyli zachowanie...
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On stability of iodine doped TiO2 electrodes in pH varied aqueous electrolytes
PublikacjaW pracy przedstaiono charakterystykę elektrochemiczną warstwy domieszkowanego jodem TiO2 na podłożu platynowym. Wyniki badań prowadzone w elektrolitach o różnym pH pozowoliły na określenie właściwości na granicy faz elektroda - elektrolit. Wyznaczono zależność potencjału pasma płaskiego od pH elektrolitu, a charakter otrzymanej funkcji potwirdził stabilność proszku I-TiO2 w kontakcie s roztworem.
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High temperature oxidation of porous alloys for solid oxide fuel cell applications
PublikacjaW pracy proszki PI600, 317L i 430L stali użyto do przygotowania porowatych metalowych podłoży dla tlenkowych ogniw paliwowych. Po spiekaniu w różnych temperaturach oceniana była ich porowatość i wysokotemperaturową odporność na korozję. Cykliczna analiza termograwimetryczna, dyfraktometria rentgenowska i obrazów SEM były używane do opisu właściwości tych porowatych stopów. Właściwości elektryczne badano dla wybranych próbek. Wpływ...
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The automation of test stand for engine cooling system testing
PublikacjaW rozdziale przedstawiono budowę stanowiska do badań układu chłodzenia silnika samochodowego typu M111920. Układ był wyposażony w obwód podgrzewania paliwa gazowego i układ akumulacji ciepła. Stanowisko wyposażono w liczne termopary do pomiaru temperatur płynów i części metalowych silnika. Ważnym opracowanym zagadnieniem było rejestrowanie wielu pomiarów w czasie rzeczywistym, do czego użyto sieci transmisji danych CAN.
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Synthesis and electrochemical characterization of poly(3,4-ethylenedioxythiophene) modified by iron hexacyanocobaltate
PublikacjaPraca dotyczy sposobu syntezy oraz elektrochemicznej charakterystyki materiału kompozytowego złożonego z poli(3,4-etylenodioksytiofenu) i heksacyjanokobaltanu(III) żelaza(II). Wybrany materiał badany był przy użyciu spektroskopii impedancyjnej, chronopotencjometrii oraz woltamperometrii cyklicznej w kontakcie z elektrolitem wodnym (KCl) oraz aprotycznym (LiPF6 w mieszaninie węglanu etylenu i węglanu propylenu). Materiał charakteryzuje...