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Wyniki wyszukiwania dla: AMBIENT TEMPERATURE INFLUENCE
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Temperature-dependent structure-property modeling of viscosity for ionic liquids
PublikacjaIn this paper we present the methodology for assessing the ionic liquids' viscosity at six temperature points (25, 35, 45, 50, 60 and 70 [C]), which utilizes only the in silico approach. The main idea of such assessment is based on the "correction equation" describing the correlation between experimentally measured viscosity and theoretically derived density (calculated with use of molecular mechanics), given at 6 different temperature...
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Extended phase diagram of RNiC2 family: Linear scaling of the Peierls temperature
PublikacjaPhysical properties for the late-lanthanide-based RNiC2 (R = Dy, Ho, Er, and Tm) ternary compounds are reported. All the compounds show antiferromagnetic ground state with the Néel temperature ranging from 3.4 K for HoNiC2 to 8.5 K for ErNiC2. The results of the transport and galvanomagnetic properties confirm a charge density wave state at and above room temperature with transition temperatures TCDW = 284, 335, 366, and 394 K for...
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Influence of external walls' thermal capacitance on indoor thermal comfort
PublikacjaThe doctoral thesis presents the results of numerical investigations on the influence of walls’ thermal capacitance on indoor thermal comfort. A proper set of thermal parameters of a building structure can considerably limit the heating / cooling demand, and passively increase the indoor thermal comfort. However the effect of building thermal capacitance on indoor conditions is complex and not always beneficial. Among a great number...
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High temperature corrosion evaluation and lifetime prediction of porous Fe22Cr stainless steel in air in temperature range 700–900 °C
PublikacjaThis work describes a high temperature corrosion kinetics study of ~30% porous Fe22Cr alloys. The surface area of the alloy (~0.02 m2 g-1) has been determined by tomographic microscopy. The weight gain of the alloys was studied by isothermal thermogravimetry in the air for 100 hours at 700 - 900 °C. Breakaway oxidation was observed after oxidation at 850 °C (~100 hours) and 900 °C (~30 hours). The lifetime prediction shows the...
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Impact of low-temperature sintering on the Fe-based amorphous coatings
PublikacjaBulk metallic glasses (BMGs) have gained a lot of attention in recent years due to their outstanding properties such as high hardness and excellent wear and corrosion resistance. However, they are restricted in industrial applications due to their extreme brittleness. Iron based amorphous coatings from BMGs are the best solution to use them by overcoming the problem of extreme brittleness. The coatings can be sprayed by various...
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Determination of ability of machines with hydraulic drive during start-up in low ambient temperatures
PublikacjaW artykule przedstawiono sposoby określania zdatności maszyn z napędem hydraulicznym podczas rozruchu w niskich temperaturach otoczenia. Przedstawiono wyniki badań eksperymentalnych i symulacji komputerowej nagrzewania się układów maszyny roboczych i zespołów hydraulicznych podczas rozruchu w warunkach szoku termicznego.
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Analytical Study of Sliding Instability due to Velocity- and Temperature-Dependent Friction
PublikacjaThe instability of sliding causes deterioration of performance characteristics of tribosystems and is undesired. To predict its occurrence, the motion of a body of a one-degree-of-freedom system with friction is investigated about the steady sliding equilibrium position. The motion equation is formulated with the friction coefficient dependent on the sliding velocity and contact temperature changing due to transient heat conduction...
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A Theoretical and Experimental Study of Moderate Temperature Alfa Type Stirling Engines
PublikacjaThe Stirling engine is a device that allows conversion of thermal energy into mechanical energy with relatively high efficiency. Existing commercial designs are mainly based on the usage of high temperature heat sources, whose availability from renewable or waste heat sources is significantly lower than that of moderate temperature sources. The paper presents the results of experimental research on a prototype alpha type Stirling...
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Investigation of the temperature modulation parameters on semiconductor gas sensor response
PublikacjaIn this work we present the results of the investigation of the sensing properties of semiconductor gas sensors with a sinusoidally modulated temperature in the presence of synthetic air (SA) and three volatile air pollutants, i.e. NH3, NO2 and SO2. The measurements were performed for different average sensor heater temperatures and the amplitude of the modulation signal. In addition, the extraction of features from the sensor...
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Numerical simulation of temperature distribution of heat flow on reservoir tanks connected in a series
PublikacjaThe flow of temperature distribution through a medium in thermodynamic studies plays an important role in understanding physical phenomena in chemical science and petroleum engineering, while temperature distribution indicates the degree of reaction that must be undergone to obtain the final product. Therefore, this paper aims to present and apply the exponential matrix algorithm (EMA), differential transformation algorithm (DTA),...
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Reliability of acicular grindable thermocouples for transient temperature measurements at sliding contacts
PublikacjaAcicular grindable thermocouples represent an interesting and prospective technique of temperature measurements at sliding contacts. This study aimed at the investigation of their reliability and accuracy as applied to the friction materials of various classes in contact with steel. The tests were conducted on a pin-on-disc tribometer under stationary and transient regimes. The experimental results were validated by comparing the...
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The effect of the temperature change rate on determination of the criticalpitting temperature of stainless steels
PublikacjaPrzedstawiono wyniki badań wpływu szybkości zmian temperatury na wyznaczaną krytyczną temperaturę korozji wżerowej. Badania stali 316L przeprowadzono metodą termometrii cyklicznej. Stwierdzono, że zwiększenie szybkości zmian temperatury związane jest ze zwiększeniem wyznaczonej temperatury krytycznej. Zależność krytycznej temperatury korozji wżerowej od szybkości korozji ma charakter liniowy. Wartości krytycznej temperatury korozji...
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Performance of the very high-temperature heat pump with low GWP working fluids
PublikacjaTraditional heat pumps are a very attractive pro-ecological solutions for a number of applications, including providing of heating or heat recovery from industrial processes. The application range of heat pumps could be greatly enlarged when the operating temperature would be increased to 130-150°C and/or the temperature lift can be increased to 50-100 K. In the paper, the very high temperature vapour-compressor based single stage...
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ZnO ALD-Coated Microsphere-Based Sensors for Temperature Measurements
PublikacjaIn this paper, the application of a microsphere-based fiber-optic sensor with a 200 nm zinc oxide (ZnO) coating, deposited by the Atomic Layer Deposition (ALD) method, for temperature measurements between 100 and 300°C, is presented. The main advantage of integrating a fiber-optic microsphere with a sensing device is the possibility of monitoring the integrity of the sensor head in real-time, which allows for higher accuracy during...
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Signal filtering method of the fast-varying diesel exhaust gas temperature
PublikacjaThe paper presents the problem of the impact of external distortions originating on laboratory test stands on the results of measurements of fast-varying diesel exhaust gas temperature. It has been stressed how significant the aspect of the test stand adaptation is during an experiment to ensure the smallest possible impact. This paper, however, focuses on the methods of mathematical processing of a signal recorded during experimental...
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The effect of elevated temperature on LCF damage growth in 2024AA – Experiment and modeling
PublikacjaThis paper presents the results of experimental low-cycle fatigue (LCF) tests conducted on EN-AW 2024 alloy in T3511 temper at 100 ◦C, 200 ◦C and 300 ◦C. The material’s basic fatigue characteristics were determined, such as fatigue life curve and cyclic strain curve. Both the hysteresis loop and nature of fracture surfaces obtained in macro- and microscopic observations (scanning electron microscope, SEM) were accounted for. The...
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The chemical and mechanical pressure influence on chromium luminescence
Dane BadawczeIn this study, we aim to compare the changes in the luminescence properties of Ga2O3:Cr3+ modified by Al or Sc ion substitution (chemical pressure) and hydrostatic pressure. We find the same behavior for Ga2–xAlxO3:Cr3+ and different behavior for Ga2–xScxO3:Cr3+ in terms of the optical properties under chemical and mechanical pressure. We consider Al...
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Influence of controlled crystallization and SrF2 content on the structure and properties of Eu3+ doped phosphate glasses
Dane BadawczeThe attached data contains the results of measurements of phosphate glasses and glass-ceramics doped with Eu. On their basis, the new material was characterized and the influence of the SrF2 addition on the glass structure was determined. In addition, the influence of the SrF2 content and controlled crystallization on the luminescent properties of Eu3+...
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Field Evaluation of High Modulus Asphalt Concrete Resistance to Low-Temperature Cracking
PublikacjaHigh-modulus asphalt concrete has numerous advantages in comparison to conventional asphalt concrete, including increased resistance to permanent deformations and increased pavement fatigue life. However, previous studies have shown that the construction of road pavements with High Modulus Asphalt Concrete (HMAC) may significantly increase the risk of low-temperature cracking. Those observations were the motivation for the research...
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Sea surface temperature distribution during upwelling along the Polish Baltic coast
PublikacjaAmong over 150 maps of sea surface temperature in the Polish Baltic coastal region derived from satellite data during the warm period of the year (April-October) in 2000-2002, 41 cases were noted where its distribution showed characteristic features indicating the occurrence of coastal upwelling. The fundamental parameters of range, probability of occurrence and temperature modification caused by water from deeper sea layers...
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High Temperature Air Combustion and Gasification (HTAC; HTAG)
PublikacjaCombustion and gasification technology utilizing high-cycle regenerative air/steam preheater has drawn increased attention in many application areas. The process is to be realized at temperature level above ash melting point using highly preheated agent. The use of highly preheated media above 900oC provides additional energy in to conversion processes and results in considerable changes to the design of combustion and gasification...
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An Influence of Factors of Flow Condition, Particle and Material Properties on Slurry Erosion Resistance
PublikacjaThe degradation of materials due to slurry erosion is the serious problem which occurs in the power industries. The paper presents actual knowledge about an influence of individual factors connected with flow conditions, particles and material properties on the slurry erosion resistance. Among the factors connected with operating conditions, an influence of impact angle, and velocity of impact, particle concertation and liquid...
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Enhanced Visible Light Active WO3 Thin Films Toward Air Purification: Effect of the Synthesis Conditions
PublikacjaTaking into consideration, our current environmental situation in the world people should face with growing problem of air and water pollution. Heterogeneous photocatalysis is highly promising tool to improve both, air and water quality through decomposition/mineralization of contaminations directly into harmless CO2 and H2O under ambient conditions. In this contribution we focused on the synthesis of self-assembly WO3 thin films...
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Analysis of unsteady flow forces on the thermowell of steam temperature sensor
PublikacjaIn this paper, 3D numerical analysis of unsteady flow forces acting on the measuring sheath of steam temperature is presented. According to that purpose, the CFD (Computation Fluid Dynamic [1]) approach has been used. The nonstationary of fluid acting on the measuring sheath such as: Strouhal frequency, amplitude of pressure, structure of vortex, peak of pressure, field of pressure, field of velocity etc. are studied analytically...
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Influence of Sn and Pb Ions Substitutions on Dielectric Properties of Barium Titanate
PublikacjaThe results of the microstructural and dielectric measurements of (Ba1-xPbx)(Ti1-xSnx)O3 (BPTSx) (x = 0, 0.05, 0.10, 0.30) polycrystalline samples are presented. The samples were obtained by means of a high temperature synthesis and their expected stoichiometry was confirmed by energy dispersive spectroscopy (EDS) measurements. The dielectric properties of BPTSx were studied with the use of broadband dielectric spectroscopy. The...
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The Effect of Calcination Temperature on Structure and Photocatalytic Properties of WO3/TiO2 Nanocomposites
PublikacjaSeries ofWO3/TiO2 nanocompositeswere obtained by hydrothermal method followed by calcination in the temperature range from 400∘C to 900∘C. The characteristics of photocatalysts by X-ray diffractometry (XRD), scanning electron microscope (SEM), and diffuse reflectance spectroscopy (DRS) showed that increasing the calcination temperature from 400 to 900∘C resulted in change of photocatalytic activity under UV-Vis light.Moreover,...
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Temperature Coefficient of Electronic Polarizability in Thin Polymer Films Deposited on Si and SiO2 Substrates Determined via Spectroscopic Ellipsometry
PublikacjaEllipsometry is widely used to determine the thermo-optical properties of thin polymer films. However, if the thermo-optic coefficient (TOC) and the linear thermal expansion coefficient (LTEC) are to be used to determine the temperature coefficient of electronic polarizability (TCEP) in thin polymer films, their values must be determined with the greatest possible accuracy, as both have the opposite effect. In this article,...
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Evaluation of Asphalt Mixture Low-Temperature Performance in Bending Beam Creep Test
PublikacjaLow-temperature cracking is one of the most common road pavement distress types in Poland. While bitumen performance can be evaluated in detail using bending beam rheometer (BBR) or dynamic shear rheometer (DSR) tests, none of the normalized test methods gives a comprehensive representation of low-temperature performance of the asphalt mixtures. This article presents the Bending Beam Creep test performed at temperatures from −20...
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FEM and experimental investigations of concrete temperature field in the massive stemwall of the bridge abutment
PublikacjaThe paper deals with the prediction of early-age concrete temperature of cast-in-place stemwall of the bridge abutment. The considered object is an arch bridge located in Gda´nsk. In the case of massive structures, it is particularly important to not exceed the temperature difference between the core and the concrete surface. Too high temperature gradient generates an increase in thermal stresses, what could be the reason of exceeding...
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High temperature drying of beech with content of tension wood
PublikacjaThe presented artcle is focused on comparison of tension and normal wood of beech (Fagus sylvatica L.) in a high-temperature drying process. Samples of 26 mm thickness were selected from sapwood zone with different angle of growth rings. The article evaluated properties of tension and normal wood before and after drying process. Properties which are monitored were moisture, moisture gradients, covering tests, colour changes and...
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The Influence of Camera and Optical System Parameters on the Uncertainty of Object Location Measurement in Vision Systems
PublikacjaThe article presents the influence of the camera and its optical system on the uncertainty of object position measurement in vision systems. The aim of the article is to present the methodology for estimating the combined standard uncertainty of measuring the object position with a vision camera treated as a measuring device. The identification of factors affecting the location measurement uncertainty and the determination of their...
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High-temperature heat pumps – potential technology for heat recovery and production of process heat
PublikacjaIn the paper, the high temperature vapour compressor based heat pump with a selection of working fluids, both perspective and ecological ones, is considered. Such system is not yet commercially available on the market and in author’s opinion it has significant potential for various applications. In the presented analysis it was assumed that the heat source has a temperature of 50oC and the temperature lift is 60, 80 and 100K respectively....
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Temperature distribution of supercapacitors prepared by various technologies
PublikacjaSupercapacitors, also known by different names such as electrostatic double-layer capacitors (EDLCs) or ultra-capacitors, are electrical storage devices still in development. These devices require fast and reliable methods of assessing their state-of-health. Thermographic imaging is a method which can be applied with this aim due to its popularity, and the high negative impact of overheating on a supercapacitor’s parameters. Moreover,...
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The effect of the temperature change rate on determination of the critical pitting temperature of stainless steels
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Role of the Hydroxyl Groups Coordinated toTiO2 Surface on the Photocatalytic Decomposition of Ethylene at Different Ambient Conditions
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Cold Start Emissions of Spark-Ignition Engines at Low Ambient Temperatures as an Air Quality Risk
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Excess Emissions and Fuel Consumption of Modern Spark Ignition Passenger Cars at Low Ambient Temperatures
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Chapter 15 : Methods of determination of correct operation area for hydraulic component in low ambient temperatures
PublikacjaW artykule przedstawiono wyniki badań eksperymentalnych zespołów hydraulicznych: silników satelitowych, silników orbitalnych, pomp i silników zębatych, rozdzielaczy suwakowych w tym proporcjonalnych, pomp tłoczkowych, siłowników w warunkach szoku termicznego w celu określenia obszarów parametrów prawidłowego i nieprawidłowego rozruchu nie tylko tych badanych zespołów. Została stworzona baza danych z wartościami współczynników...
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Spectroscopic properties and location of the Ce3+ energy levels in Y3Al2Ga3O12 and Y3Ga5O12 at ambient and high hydrostatic pressure
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High temperature corrosion and corrosion protection of porous Ni22Cr alloys
PublikacjaIn this work corrosion kinetics of the porous IN625 alloy is studied in the temperature range of 700 °C – 800 °C in air and humidified hydrogen for up to 1000 hours. Moreover, an effective and simple method of reducing corrosion rates of porous alloys by the infiltration of the rare earths elements is shown. Modification by the yttrium containing precursor reduces the corrosion rate by a factor of 50 in air at 700 °C so that the...
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Electrochemical capacitor temperature fluctuations during charging/discharging processes
PublikacjaThepaperpresentsaproposalofusingadditionalstatisticalparameterssuchas:standarddeviation,variance, maximum and minimum increases of the observed value that were determined during measurements of temperature fields created on the surface of the tested electrochemical capacitor. The measurements were carriedoutusingthermographicmethodsinordertosupportassessmentoftheconditionofelectrochemical capacitorunderclassicdurabilitytestsbasedonmethodsofdeterminationofcapacityandequivalentseries...
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Numerical analysis of high temperature minichannel heat exchanger for recuperative microturbine system
PublikacjaConsidering the development of energy sector, distributed small-scale power generation, e.g., gas micro-CHP, is attracting considerable interest. In such installations, the heat exchanger is one of the key components possessing a significant influence on overall performance. Most studies concentrate on units operating below 900C, which do not fulfil the requirements of gas micro-CHP. Therefore, there remains a challenge to design...
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Hyaluronan-Chondroitin Sulfate Anomalous Crosslinking Due to Temperature Changes
PublikacjaGlycosaminoglycans are a wide class of biopolymers showing great lubricating properties due to their structure and high affinity to water. Two of them, hyaluronic acid and chondroitin sulfate, play an important role in articular cartilage lubrication. In this work, we present results of the all-atom molecular dynamics simulations of both molecules placed in water-based solution. To mimic changes of the physiological conditions,...
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A new viscoelastic method of calculation of low-temperature thermal stresses in asphalt layers of pavements
PublikacjaThe paper presents a new method of calculation of thermal stresses in asphalt layers of pavements induced by cooling or heating. The method, developed by the author, is based on the analytical solution for the linear viscoelastic Burgers model extended numerically for the case of asphalt layers whose rheological parameters are strongly dependent on temperature. The coefficient of thermal expansion and Poisson’s ratio may optionally...
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Low temperature broad band dielectric spectroscopy of multiferroic Bi6Fe2Ti3O18 ceramics
PublikacjaIn the present research the tool of broadband dielectric spectroscopy was utilized to characterize dielectric behavior of Bi6Fe2Ti3O18 (BFTO) Aurivillius-type multiferroic ceramics. Dielectric response of BFTO ceramics was studied in the frequency domain (Δν=0.1Hz – 10MHz) within the temperature range ΔT=-100°C – 200°C. The Kramers-Kronig data validation test was employed to validate the impedance data measurements and it was found...
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High-Temperature Structural and Electrical Properties of BaLnCo2O6 Positrodes
PublikacjaThe application of double perovskite cobaltites BaLnCo2O6−δ (Ln = lanthanide element) in electrochemical devices for energy conversion requires control of their properties at operating conditions. This work presents a study of a series of BaLnCo2O6−δ (Ln = La, Pr, Nd) with a focus on the evolution of structural and electrical properties with temperature. Symmetry, oxygen non-stoichiometry, and cobalt valence state have been examined...
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Determination of chlorine concentration using single temperature modulated semiconductor gas sensor
PublikacjaA periodic temperature modulation using sinusoidal heater voltage was applied to a commercial SnO2 semiconductor gas sensor. Resulting resistance response of the sensor was analyzed using a feature extraction method based on Fast Fourier Transformation (FFT). The amplitudes of the higher harmonics of the FFT from the dynamic nonlinear responses of measured gas were further utilized as an input for Artificial Neural...
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EXHAUST TEMPERATURE MEASUREMENTS OF THE MARINE TURBOCHARGED DIESEL ENGINES IN OPERATION
PublikacjaThe article presents the selected metrology issues concerning the exhaust temperature of the turbocharged marine engines during operation. The special concern has been paid on existing disturbances as well as thermodynamical interpretation of the recorded measurement signal. A diagnostic informativeness of the standard exhaust temperature’s measurements has worked out while the engine runs in steady states has been also considered...
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High-temperature properties of titanium-substituted yttrium niobate
Publikacjahe defect fluorite titanium-doped yttrium niobate samples Y3Nb1−xTixO7−δ have been synthesized and investigated by the means of high-temperature X-ray diffraction, dilatometry, and thermogravimetry. Thermal expansion coefficients (TECs) as well as chemical expansion coefficients for material with 5, 10, and 15 mol% of titanium were determined. All investigated samples exhibit chemical contraction caused by Ti doping. The values...
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Improvement of Oxygen Electrode Performance of Intermediate Temperature Solid Oxide Cells by Spray Pyrolysis Deposited Active Layers
PublikacjaIntermediate temperature solid oxide fuel cells oxygen electrodes are modified by active interfacial layers. Spray pyrolysis is used to produce thin (≈500 nm) layers of mixed ionic and electronic conductors: Sm0.5Sr0.5CoO3−δ (SSC), La0.6Sr0.4CoO3−δ (LSC), La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF), and Pr6O11 (PrOx) on the electrode–electrolyte interface. The influence of the annealing temperature on the electrode polarization (area specific...