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Search results for: HEAT TRANSFER SURFACE AREA
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Study of oxygen electrode reactions on symmetrical porous SrTi0.30Fe0.70O3-δ electrodes on Ce0.8Gd0.2O1.9 electrolyte at 800 °C–500 °C
PublicationIron doped strontium titanates (SrTi1-xFexO3-δ) are an interesting mixed ionic-electronic conductor model used to study basic oxygen reduction/oxidation reactions. In this work, we performed an impedance spectroscopy study on symmetrical porous SrTi0.30Fe0.70O3-δ (STF70) electrodes on a ceriabased electrolyte. The sample was measured in varying oxygen concentration: from 0.3% to 100% in 800 °C - 500 °C temperature range. Low polarisation...
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Visible light photocatalytic activity of ionic liquid-TiO2 spheres: effect of the ionic liquid's anion structure
PublicationThe effect of the ionic liquid’s (IL) anion type ([BIMIM][X], where X= [Br], [PF6] or [OctSO4]) and content on the morphology, surface properties and photoactivity of TiO2 obtained by solvothermal method has been systematically investigated. Our results revealed that the presence of [Br], [OctSO4] anions favors formation of anatase phase, while presence of [PF6] anion causes formation of mixture of anatase and Ti(OH)PO4 phases....
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Theoretical studies of fragmentation processes of neutral and ionized furan molecule
PublicationThis PhD thesis focuses on the fragmentation mechanism of the furan molecule in the gas phase. The approach taken in this work comprised of three theoretical methodologies considering the dynamical, energetical and entropic aspects of the studied process. First, molecular dynamics simulations were performed. Next, the potential energy surfaces were explored at the DFT/B3LYP level of theory. Finally, a new statistical Microcanonical...
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Mode shapes of a beam and plate with defects, obtained by experimental modal analysis
Open Research DataThe DataSet contains the experimental results of the first mode shape for a beam and a plate.
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Rubber wastes recycling for developing advanced polymer composites: A warm handshake with sustainability
PublicationRecycling and management of rubber wastes experiences an early-stage maturity in the quest for sustainable and circular materials. Up to now, solutions proposed for sustainable development of rubber wastes are limited, so that properties and performance features of recycled products are inadequate for practical applications. Herein, an experimental protocol is introduced for manufacturing semi-sustainable polymer composites based...
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Local Nusselt number evaluation in the case of jet impingement
PublicationJet impingement still is one of demanding cases regarding computational fluid dynamics, due to its highly turbulent behaviour, with occurrence of turbulent-laminar transition. Even recently developed methods exhibit some drawbacks – RANS based simulations lack accuracy, LES and DNS based ones require too much computational time. Hybrid methods also exist, but their development and validation is in progress. Nevertheless, CFD application...
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Molecular Strategy for Survival at a Critical High Temperature in Eschierichia coli
PublicationThe molecular mechanism supporting survival at a critical high temperature (CHT) in Escherichia coli was investigated. Genome-wide screening with a single-gene knockout library provided a list of genes indispensable for growth at 47°C, called thermotolerant genes. Genes for which expression was affected by exposure to CHT were identified by DNA chip analysis. Unexpectedly, the former contents did not overlap with the latter except...
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Preparation and Characterization of Nanomaterial Consisting of Silica Aerogel & Carbon Tested as an Electrode in Non-Aqueous Media Containing Lithium Salt.
PublicationSilica aerogel (SiO2ag) was combined with carbonaceous material in the pyrolysis process of hydrocarbons. The obtained nanocomposite SiO2ag/C was amorphous, partially preserving the porous structure of SiO2ag. The specific surface area changes from 445.6 m2/g for pure SiO2ag to 205.52 m2/g SiO2ag/C. The 29Si MAS-NMR shows a three-dimensional matrix with silicon atoms connected to other silicon atoms by four...
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Enhancement of the Magnetoresistance in the Mobility‐Engineered Compensated Metal Pt 5 P 2
PublicationThe magnetoresistance (MR) in nonmagnetic materials continues to be a fertile research area in materials science. The search for giant, positive MR has been limited to a rather small window of materials such as high-mobility semimetals in single-crystalline form. Here, the observation of a very large positive MR in metallic Pt5P2 in polycrystalline form is reported. The observations reveal that improvement of the crystallinity...
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Dispersive Micro‐Solid Phase Extraction of Selected Metals in Water and Food Samples Followed by ICP‐OES Analysis: Method Development, Analysis of Real Samples and Greenness Evaluation
PublicationMultiwalled carbon nanotubes (MWCNTs) are well-known adsorbents because of their high surface area, layered and hollow architecture, hydrophobicity, and multiple and easily accessible adsorption sites. In this study, MWCNTs were used for dispersive micro-solid-phase extraction of various metal chelates in environmental and food samples. Different parameters such as concentration of the chelating reagent, the sorbent dosage, the...
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A Reduction Method for Bathymetric Datasets that Preserves True Coastal Water Geodata
PublicationWater areas occupy over 70 percent of the Earth’s surface and are constantly subject to research and analysis. Often, hydrographic remote sensors are used for such research, which allow for the collection of information on the shape of the water area bottom and the objects located on it. Information about the quality and reliability of the depth data is important, especially during coastal modelling. In-shore areas are liable...
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Wpływ mikrosfer-frakcji odpadów paleniskowych na mikrostrukturę i wybrane właściwości uzytkowe
PublicationIn this study, the microspheres samples were collected from national power station „Dolna Odra”. In this study, the following materials were used: Portland cement class 32,5R and aggregates of 2-8 and 8-16 fractions and natural sand with a maximum grain size of 2 mm and water. Concrete mixtures were made with microspheres additions of 15%, 25% and 40%. A constant water to binder ratio (w/b) of 0,52 was used throughout the investigation....
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Investigation of catalytic layers on anode for solid oxide fuel cells operating with synthetic biogas
PublicationIn this paper solid oxide fuel cells operating with dry synthetic biogas have been examined. In order to increase their stability the layers of CuO-CeO2, Cu1.3Mn1.7O4 and Y0.08Sr0.92Ti0.8Fe0.2O3 -δ have been deposited on the Ni-YSZ anode site. These layers should catalyze the internal biogas reforming and prevent the carbon deposition on the anode site. It has been found that CuO-CeO2 and Cu1.3Mn1.7O4 catalysts led to an increase...
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High temperature oxidation behavior of SUS430 SOFC interconnects with Mn-Co spinel coating in air
PublicationIn this study, SUS430 alloy is evaluated for its high temperature corrosion properties as a possible material for interconnects of solid oxide fuel cells (SOFCs). Samples are coated with Mn-Co by commercial physical vapor deposition (PVD) process and oxidized in air for 1250 h at 800 °C. A dense cubic Mn-Co-Fe spinel layer is formed on the surface, showing great effect on corrosion reduction compared with the samples without coating....
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Resistive gas sensors – Perspectives on selectivity and sensitivity improvement
PublicationResistive gas sensors are very popular and relatively inexpensive; they can operate at elevated or room temperature for years on end. The main disadvantage of resistive gas sensors is their limited selectivity and sensitivity, but various methods have been applied to improve their behavior. The composition of the porous gas sensing layer, or changes in the sensor’s operating temperature, can enhance the gas detection ability. Furthermore, emerging...
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Electrocatalytic performance of oxygen-activated carbon fibre felt anodes mediating degradation mechanism of acetaminophen in aqueous environments
PublicationCarbon felts are flexible and scalable, have high specific areas, and are highly conductive materials that fit the requirements for both anodes and cathodes in advanced electrocatalytic processes. Advanced oxidative modi- fication processes (thermal, chemical, and plasma-chemical) were applied to carbon felt anodes to enhance their efficiency towards electro-oxidation. The modification of the porous anodes results in increased...
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Retrievable strain measuring system in screw displacement piles - readings and results interpretation problems
PublicationStatic load tests on foundation piles are generally carried out in order to determine load – displacement characteristic of the pile. For more detailed information, e.g. force distribution along the shaft, load transfer mechanism and characteristics of soil-structure interaction (unit resistance curves t-z, q-z) additional pile instrumentation is required. Most popular techniques focus on direct concrete strain measurements and...
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Distortion of speech signals in the listening area: its mechanism and measurements
PublicationThe paper deals with a problem of the influence of the number and distribution of loudspeakers in speech reinforcement systems on the quality of publicly addressed voice messages, namely on speech intelligibility in the listening area. Linear superposition of time-shifted broadband waves of a same form and slightly different magnitudes that reach a listener from numerous coherent sources, is accompanied by interference effects...
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Nonlinear properties of the Gotland Deep – Baltic Sea
PublicationThe properties of the nonlinear phenomenon in water, including sea water, have been well known for many decades. The feature of the non homogeneous distribution of the speed of sound along the depth of the sea is very interesting from the physical and technical point of view. It is important especially in the observation of underwater area by means of acoustical method ( Grelowska et al ., 2013; 2014). The observation of the underwater...
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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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The use of lightweight aggregate saturated with PCM as a temperature stabilizing material for road surfaces.
PublicationThis paper presents the possibility of adding lightweight building aggregates to increase the stability – mechanical as well as thermal - of constructions and road objects. This stability can be achieved through saturating the porous granules of aggregate with a phase-change material (PCM) that allows the accumulation of solar heat. Intense solar radiation, especially during the summer, can cause the asphalt on road surfaces, bridges...
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Application of Analytic Signal and Smooth Interpolation in Pulse Width Modulation for Conventional Matrix Converters
PublicationThe paper proposes an alternative and novel approach to the PWM duty cycles computation for Conventional Matrix Converters (CMC) fed by balanced, unbalanced or non–sinusoidal AC voltage sources. The presented solution simplifies the prototyping of direct modulation algorithms. PWM duty cycles are calculated faster by the smooth interpolation technique, using only vector coordinates, without trigonometric functions and angles. Both...
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Vertical Temperature Stratification of the Gulf of Gdansk Water
PublicationThe Baltic Sea is characterized by variable hydroacoustic conditions, which depend on hydrological conditions throughout the year. The temperature of the water is the factor that has the greatest impact on the changes in the speed of the sound in this basin. Even at a small depth, we can observe a large temperature gradient affecting the accuracy of the conducted research using hydroacoustic devices. A characteristic feature of...
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Liver cell carcinoma - Male, 8 - Tissue image [9070730015323421]
Open Research DataThis is the histopathological image of LIVER AND INTRAHEPATIC BILE DUCTS tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Wpływ stopowania laserowego z użyciem nanorurek węglowych stopu Ti13Nb13Zr do zastosowań biomedycznych na jego wybrane własności mechaniczne
PublicationDo eksperymentu użyto stopu tytanu Ti13Nb13Zr, który ze względu na swój skład chemiczny i właściwości mechaniczne stanowi materiał do zastosowań w inżynierii medycznej. Celem pracy była ocena wpływu stopowania laserowego stopu Ti13Nb13Zr z powłoką z wielościennych nanorurek węglowych na jego właściwości mechaniczne (chropowatość, nanotwardość, moduł Younga). Do wytworzenia powłoki węglowej wykorzystano metodę osadzania elektroforetycznego (EDP)....
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Hydrodynamic reanalysis of ice conditions in the Baltic Sea using the PM3D model
Open Research DataThe dataset contains the results of numerical modeling of sea ice in the Baltic Sea since 1998. A long-term reanalysis was performed using the three-dimensional hydrodynamic model PM3D (Kowalewski and Kowalewska-Kalkowska, 2017), a new version of the M3D model (Kowalewski, 1997). A numerical dynamic-thermodynamic model of sea ice (Herman et al. 2011)...
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Wybrane zagadnienia optymalizacji organizacji ruchu kolejowego w celu minimalizacji kosztów energii elektrycznej
PublicationW artykule przedstawiono podział kosztów w transporcie kolejowym z uwzględnieniem kosztów wewnętrznych przedsiębiorstwa, do których zaliczają się między innymi koszty dostępu do infrastruktury, czy koszty energii. Stwierdzono, że przy odpowiedniej organizacji ruchu pociągów na sieci kolejowej, bez ponoszenia dodatkowych nakładów na infrastrukturę i specjalistyczne urządzenia, można znacznie ograniczyć zużycie energii, a co za tym...
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Method of evaluation of lubricating ability of lube oils and fuels in energetistic formulation
PublicationThe paper presents an interpretation of operation of a boundary layer of a lubricating medium. A model of the homogeneous Poisson process has been proposed to assess the deterioration process of the layer's operation. The assessment considers the original interpretation of operation of a boundary layer, as a lubricity measure of a boundary layer of any lubricant. In the submitted proposal the operation of a boundary layer is understood...
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Permanent traffic counting stations - Expressway S6 in Gdansk (dataset containing 5-min aggregated traffic data and weather information)
Open Research DataThe data includes traffic data from permanent traffic count station located on the expressway S6 in the Tri-City Agglomeration area in Poland. The data covers the three year period between 2014 and 2017 and one direction of traffic (southbound).
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Assessment of Surface Water Resources Based on Different Growth Scenarios, for Borkena River Sub-basin, Awash River Basin, Ethiopia
PublicationThe total annual river flow at the Awash Kombolcha sub-basin of the Borkena river station was estimated to be 4.6 billion cubic meters by 2019-2030. The current average annual flow at the exit measurement station is 544.5Mm3 of the water resources available in the study area. The monthly peak flow of the Borkena River occurs from July to September. In addition, the highest monthly average flow is in August and the lowest is...
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Spatiotemporal dynamics of the active perirheic zone in a natural wetland floodplain
PublicationAbstract The ecologically and biogeochemically significant perirheic zone is a part of the floodplain where waters originating from both the river and adjacent floodplain are present. In this study, we investigate the spatiotemporal dynamics of the active perirheic zone, i.e. river and floodplain waters and their transient mixing extent. This is achieved by using the Hydraulic Mixing-Cell method, a complement to a fully integrated...
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Facet effect of TiO2 nanostructures from TiOF2 and their photocatalytic activity
PublicationIn this study, special attention is focused on the design of TiO2 morphology and microstructure in the two-step preparation procedure using TiOF2 as a precursor to study their photodegradation mineralization efficiency. Firstly, TiOF2 was synthesized by a simple solvothermal method using titanium(IV) tetrafluoride, which was further used as a precursor in preparation of anatase 2D nanosheets, octahedral, decahedral, and rectangular prisms...
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Thermal dewetting as a method of surface modification of the gold thin films for surface plasmon resonance based sensor applications
PublicationHere, we report a quick and simple approach with low, optimized production costs to obtain surface plasmon resonance (SPR) based sensors fabricated through a time- and resource-effective method based on thermal dewetting of thin Au films. From the applicative point of view, the method of detection presented here should be easier to implement, since light transmission measurements seem to be much less challenging than light refractive...
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Removal of diphenols using pine biochar. Kinetics, equilibrium, thermodynamics, and mechanism of uptake
PublicationThermal pyrolysis synthesized activated biochar from the Pinus elliottii sawdust (PS) at 600° C. The obtained activated biochar (PB600) was used for the removal of three diphenols, catechol (CAT), resorcinol (RES), and hydroquinone (HYD), which are utilized mainly in different industries. The PB600 was characterized by several analytical techniques. The BET surface area of 1473 m2.g−1 and a total pore volume of 0.707 cm3 g−1 was...
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Microfluidically Frequency-Reconfigurable Compact Self-Quadruplexing Tunable Antenna with High Isolation Based on Substrate Integrated Waveguide
PublicationThis communication presents a novel concept of microfluidically frequency-reconfigurable self-quadruplexing tunable antenna for quad-band applications. At the initial design stage, a substrate-integrated square cavity is divided into four unequal quarter-mode cavity resonators by inserting an X-shaped slot on the top surface of the cavity. Applying four 50-ohm microstrip feed-lines to these four quarter-mode cavity resonators enables...
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Development, characterization and evaluation of composite adsorbent for the adsorption of crystal violet from aqueous solution: Isotherm, kinetics, and thermodynamic studies
PublicationThe purpose of this work focuses on the production and investigations of a new composite material as alternative low-cost adsorbent for the removal of crystal violet (CV) dye from waste solution. The production method was performed by in-situ thermal activation technology via extrusion process of polymer wastes containing tire rubber (50 wt%) and polyurethane foam (50 wt%) using single-screw extruder under processing temperature...
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Enhanced capacitance of composite TiO2 nanotube / boron-doped diamond electrodes studied by impedance spectroscopy
PublicationWe report on the novel composite nanostructures based on boron-doped diamond thin film grown on top of TiO2 nanotubes. The nanostructures made of BDD-modified titania nanotubes showed an increase in activity and performance when used as electrodes in electrochemical environments. The BDD thin films (~200-500 nm) were deposited using microwave plasma assisted chemical vapor deposition (MW PA CVD) onto anodically fabricated TiO2...
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Electroactive polymer/graphene oxide nanostructured composites; evidence for direct chemical interactions between PEDOT and GOx
PublicationThis work concerns electrochemical synthesis of nanocomposites consisting of conducting polymer and reduced graphene oxide (rGOx) as electrode materials for supercapacitors. The electrosynthesis was performed in an aqueous solution of the 3,4-ethylenedioxytiophene (EDOT) monomer and graphene oxide (GOx) without supporting electrolyte. The amount of GOx was optimized to obtain the best electrochemical performance of the nanocomposite...
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Visible light photocatalysis employing TiO2/SrTiO3-BiOI composites: Surface properties and photoexcitation mechanism
PublicationA series of binary TiO2/SrTiO3 and ternary TiO2/SrTiO3_BiOI composites have been synthesized using multistep preparation method. Characterization of the obtained photocatalysts covered complex analysis including morphology + y (SEM), BET specific surface area, porosity, optical properties (DRS), chemical composition of surface (XPS), crystal structure and crystal size (XRD). UV–vis and Vis ligh induced photocatalytic activity was...
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Methodology for Carrying Out Measurements of the Tombolo Geomorphic Landform Using Unmanned Aerial and Surface Vehicles near Sopot Pier, Poland
PublicationThe human impact on the ecosystem has been particularly evident in the last century; it transforms the Earth’s surface on an unprecedented scale and brings about irreversible changes. One example is an oceanographic phenomenon known as a tombolo, i.e., a narrow belt connecting the mainland with an island lying near the shore formed as a result of sand and gravel being deposited by sea currents. The phenomenon contributes to an...
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Shipping Low Frequency Noise and Its Propagation in Shallow Water
PublicationOne of the most significant factor influencing acoustical climate of the sea is underwater noise generated by moving ships. If the considered sea area has features of the shallow water, namely the wave frequency fulfils relation f < 10c/h, where c denotes phase speed of sound, and h is depths of the sea, then in certain distance from the wave source specific image of sound pressure distribution in the mean of wave modes appears....
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Design considerations for compact microstrip resonant cells dedicated to efficient branch-line miniaturization
PublicationA conventional compact microstrip resonant cell (CMRC)has been thoroughly investigated to enhance its slow-wave properties and subsequently ensure an efficient miniaturization of a microstrip circuit. The geometry of a classic CMRC has been improved in terms of slowwave effect in two progressive steps: (i) a single-element topology has been replaced with a double-element one and (ii) a high-impedance section has been refined by...
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Electrodeposited Biocoatings, Their Properties and Fabrication Technologies: A Review
PublicationCoatings deposited under an electric field are applied for the surface modification of biomaterials. This review is aimed to characterize the state-of-art in this area with an emphasis on the advantages and disadvantages of used methods, process determinants, and properties of coatings. Over 170 articles, published mainly during the last ten years, were chosen, and reviewed as the most representative. The most recent developments...
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Effectiveness of a dual surface modification of metallic interconnects for application in energy conversion devices
PublicationA dual surface modification of an SOFC metallic interconnect with a Gd2O3 layer and an MnCo2O4 coating was evaluated. The tested samples were oxidized for 7000 h in air at 1073 K. Oxidation products were characterized using XRD, SEM-EDS, and confocal Raman imaging, and ASR was measured. The effect of gadolinium segregation at grain boundaries in Cr2O3 was evaluated using S/TEM-EDS. Area specific-resistance was measured and fuel...
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Cu supported on various oxides as a candidate catalyst for dry methane reforming in DIR-SOFCs systems
PublicationA series of Cu-support systems were tested as potential candidates for DIR-SOFC (Direct Internal Reforming SOFC) catalysts towards a dry reforming of methane (DRM). The various supports (-Al2O3, CeO2, ZrO2, SrTiO3) with comparable specific surface area (SSA), and additionally -Al2O3 with SSA an order of magnitude larger than that of the other supports has been applied. The obtained Cu-support systems were characterized in terms...
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Metal nanoparticles-assisted early diagnosis of diseases
PublicationEarly diagnosis is essential for the effective illness treatment, but traditional diagnostic approaches inevitably have major downsides. Recent advancements in nanoparticle-based biosensors have created new opportunities for accelerating diagnosis. High surface area, exceptional sensitivity, high specificity, and optical characteristics of metal and metal oxide nanoparticles have made it possible to detect a variety of health conditions...
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Systematic Water Uptake Energetics of Yttrium-Doped Barium Zirconate—A High Resolution Thermochemical Study
PublicationA combination of surface area analyzer and microcalorimetry was employed to investigate the in situ water uptake energetics and the mechanism of proton incorporation in yttrium-doped barium zirconate in the temperature range 200–400 °C. The BaZr1–xYxO3 solid solutions are made with variable yttrium content (x = 10, 20, and 30 mol %) by a controlled oxidant-peroxo synthesis method. The water uptake increases as the partial pressure...
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Multimodal Particle Swarm Optimization with Phase Analysis to Solve Complex Equations of Electromagnetic Analysis
PublicationIn this paper, a new meta-heuristic method of finding roots and poles of a complex function of a complex variable is presented. The algorithm combines an efficient space exploration provided by the particle swarm optimization (PSO) and the classification of root and pole occurrences based on the phase analysis of the complex function. The method initially generates two uniformly distributed populations of particles on the complex...
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Photocatalytical degradation of toluene and cyclohexane using LED illumination
PublicationA sol-gel process followed by hydrothermal reaction was used to prepare coupled WO3-TiO2 photocatalysts with varying amounts of WO3 in respect to TiO2 (3 mol% and 5 mol% respectively). Additionally, photocatalysts have been subjected to different calcination temperatures of 400ºC and 800ºC, which allowed us to compare how these affect photodegradation efficiency. Photocatalysts were characterized under a scanning electron microscope,...
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Underwater Acoustic Imaging of the Sea
PublicationAcoustic waves are a carrier of information mainly in environments where the use of other types of waves, for example electromagnetic waves, is limited. The term acoustical imaging is widely used in the ultrasonic engineering to imaging areas in which the acoustic waves propagate. In particular, ultrasound is widely used in the visualization of human organs - ultrasonography (Nowicki, 2010). Expanding the concept, acoustical imaging...