Filters
total: 1029
filtered: 846
Search results for: GRAPHENE OXIDE, GRAPHENE, REDUCED GRAPHENE OXIDE,
-
Activation of N2O and SO2 by the P–B Bond System. Reversible Binding of SO2 by the P–O–B Geminal Frustrated Lewis Pair
PublicationHerein, we present the first transformation of borylphosphine into borylphosphinite using nitrous oxide. Borylphosphine reacts with N2O via insertion of a single oxygen atom into the P−B bond and formation of a P−O−B bond system. Borylphosphine and borylphosphinite capture SO2 and activate it in an irreversible and reversible manner, respectively.
-
Synthesis and Spectroscopic Characterization of Selected Phenothiazines and Phenazines Rationalized Based on DFT Calculation
PublicationTwo unique structures were isolated from the phosphorylation reaction of 10H-phenothiazine.The 5,5-dimethyl-2-(10H-phenothiazin-10-yl)-1,3,2-dioxaphosphinane 2-oxide (2a) illustrates theproduct of N-phosphorylation of phenothiazine. Moreover, a potential product of 2a instability,a thiophosphoric acid 2b, was successfully isolated and structurally characterized. Molecule 2a,similarly to sulfoxide derivative...
-
Hydrogen degradation of pre-oxidized zirconium alloys
PublicationThe presence of the oxide layers on Zr alloys may retard or enhance the hydrogen entry and material degradation, depending on the layer features. This research has been aimed to determine the effects of pre-oxidation of the Zircaloy-2 alloy at a different temperature on hydrogen degradation. The specimens were oxidised in laboratory air at 350°C, 700°C, and 900°C. After, some samples were tensed at 10-5 strain rate and simultaneously...
-
The influence of photointercalaction and photochromism effects on the photocatalytic properties of electrochemically obtained maze-like MoO3 microstructures
PublicationMolybdenum oxide (α-MoO3) thin films with oriented crystalline facets were synthesised by anodization of Mo foils. The obtained samples were exposed to UV–Vis illumination in aqueous electrolytes providing different cations. The morphology and structure of modified samples were investigated. The effect of photointercalated alkali metal cations (Li+, Na+, K+) on optical and structural properties was studied using UV–vis and Raman...
-
Influence of Gd deposition on the oxidation behavior and electrical properties of a layered system consisting of Crofer 22 APU and MnCo2O4 spinel
PublicationIn the study, the surface of the Crofer 22APU ferritic steel was modified with gadolinium oxide nanoparticles and a protective-conducting layer consisting of the MnCo2O4 spinel. This system was studied in the context of application in IT-SOFC interconnects. Four types of samples were studied: unmodified steel, steel coated with a manganese-cobalt spinel layer, steel modified with gadolinium oxide nanoparticles, and a system consisting...
-
Materiały dla jednowarstwowych ogniw paliwowych
PublicationA composite material, which may be further applied as a single layer fuel cell, was synthesizes using solid state synthesis method. Composite consisted of two components. The first was a nanoeramic proton conductor - calcium doped lanthanum niobate. The second one was a nanoceramic semiconductor oxide composed of lithium, nickel and zinc oxides respectively.
-
MnCo2O4 deposited by spray pyrolysis as a protective layer for stainless steel interconects
PublicationStainless steel interconnects working in Solid Oxide Fuel Cells stacks are exposed to high temperature resulting in their corrosion. Protective layers for the hydrogen and oxygen sides are necessary to protect the interconnect material, prolongate the stack lifetime and maintain the output power. In this paper MnCo2O4 protective layer for the oxygen side of the interconnect is deposited by spray pyrolysis and is examined.
-
Thermochemistry of rare earth perovskites Na3xRE0.67−xTiO3 (RE = La, Ce)
PublicationHigh-temperature oxide melt solution calorimetry using sodium molybdate (3Na2O·4MoO3) solvent at 973 K was performed for the Na3xRE0.67−xTiO3 (RE = La, Ce) perovskite series. The enthalpies of formation of lanthanum perovskites from oxides (La2O3, Na2O, TiO2), are −107.25 ± 2.56, −93.83 ± 6.06, −80.68 ± 5.93, and −33.49 ± 4.26 kJ/mol and enthalpies of formation from elements are −1614.05 ± 5.37, −1596.44 ± 7.68, −1594.03 ± 7.58,...
-
Poloxamer: A versatile tri-block copolymer for biomedical applications
PublicationPoloxamers, also called Pluronic, belong to a unique class of synthetic tri-block copolymers containing central hydrophobic chains of poly(propylene oxide) sandwiched between two hydrophilic chains of poly(ethylene oxide). Some chemical characteristics of poloxamers such as temperature-dependent self-assembly and thermo-reversible behavior along with biocompatibility and physiochemical properties make poloxamer-based biomaterials...
-
Tuning of the plasmon resonance location in Au nanostructures coated with a ultrathin film of Al2O3 – Optical measurements and FDTD simulations
PublicationThe Au nanostructures have been coated with an ultra-thin films of amorphous aluminium oxide. Optical absorption spectra show the influence of the thickness of Al2O3 on plasmon resonance wavelength. The observed red-shift of the resonance location with the increase of the thickness of the Al2O3 film, can be explained by the change in the dielectric function of this film. It allows control of the optical spectra of the coated particles....
-
Mn-Co spinel coatings on Crofer 22 APU by electrophoretic deposition: Up scaling, performance in SOFC stack at 850 °C and compositional modifications
PublicationCeramic coatings for metallic interconnects play a key role in limiting corrosion and chromium evaporation in solid oxide cells. This study presents the upscaling of the electrophoretic deposition (EPD) technique to process Mn-Co spinels on real-dimension Crofer 22 APU interconnects and the test in a SOFC stack. Area specific resistance of long-term test conducted for 5000 h at 850 °C demonstrated that two-steps sintering has a...
-
Effect of double thermal and electrochemical oxidation on titanium alloys for medical applications
PublicationThe research focuses on the development and characterization of innovative thin hybrid oxide coatings obtained in subsequent processes of thermal (TO) and electrochemical (EO) oxidation. Four different surface modifications were investigated and the microstructure was determined, the mechanical, chemical and biological properties of the Ti-13Nb-13Zr alloy were assessed using scanning electron microscopy, X-ray dispersion analysis,...
-
Thermodynamics of solid phases containing rare earth oxides
PublicationRare earth elements (RE) are incorporated into a large variety of complex oxide phases to provide tailored mechanical, electrical, optical, and magnetic properties. Thermodynamics control phase stability, materials compatibility in use, corrosion, and transformation. This review presents, in one compilation, the thermodynamic properties of a large number of such materials and discusses systematic trends in energetics and the factors...
-
Problem of Clogging in Drainage Systems in the Examples of the Zur and Podgaje Dams
PublicationDrainage plays an extremely important role in hydraulic structures, such as earth dams. Observations of drainage in hydraulic structures under various soil conditions indicate that the phenomenon of clogging can lead to a radical reduction in the efficiency of drainage, making it non-functional within a few years after construction. This article describes the problems of drainage clogging by iron oxide in the examples of the Zur...
-
Thermal Instability of Gold Thin Films
PublicationThe disintegration of a continuous metallic thin film leads to the formation of isolated islands, which can be used for the preparation of plasmonic structures. The transformation mechanism is driven by a thermally accelerated diffusion that leads to the minimalization of surface free energy in the system. In this paper, we report the results of our study on the disintegration of gold thin film and the formation of nanoislands...
-
Progress in targeting tumor cells by using drug-magnetic nanoparticles conjugate.
PublicationTo limit the cytotoxicity of anticancer drugs against healthy cells, an appropriate carrier should be synthesized to deliver the drug to the tumor tissue only. A good solution is to anchor a magnetic nanoparticle to the molecule of the drug and to use a properly directed external magnetic field. We have shown that the improved by us synthesis of the conjugate of doxorubicin with iron-oxide magnetic nanoparticles allows a substantial...
-
TiO2-based magnetic nanocomposites with core-shell structure
PublicationThe main aim of the doctoral dissertation was preparation and characterization of photocatalysts, with particular emphasis on modified titanium (IV) oxide photocatalysts, which can be applied for the degradation of organic pollutants not susceptible to biodegradation. A particularly important aspect of the work was the development of preparation method of nanocomposites with the magnetic core-shell and photocatalyst shell (TiO2)...
-
Fault detection in the marine engine using a support vector data description method
PublicationFast detection and correct diagnosis of any engine condition changes are essential elements of safety andenvironmental protection. Many diagnostic algorithms significantly improve the detection of malfunctions.Studies on diagnostic methods are rarely reported and even less implemented in the marine engine industry.To fill this gap, this paper presents the Support Vector Data Description (SVDD) method as applied to thefault detection...
-
Is the Solid Electrolyte Interphase an Extra-Charge Reservoir in Li-Ion Batteries?
PublicationAdvanced metal oxide electrodes in Li-ion batteries usually show reversible capacities exceeding the theoretically expected ones. Despite many studies and tentative interpretations, the origin of this extra-capacity is not assessed yet. Lithium storage can be increased through different chemical processes developing in the electrodes during charging cycles. The solid electrolyte interface (SEI), formed already during the first...
-
Endothelial Dysfunction Driven by Hypoxia—The Influence of Oxygen Deficiency on NO Bioavailability
PublicationCardiovascular diseases (CVDs) are the leading cause of death worldwide. The initial stage of CVDs is characterized by endothelial dysfunction, defined as the limited bioavailability of nitric oxide (NO). Thus, any factors that interfere with the synthesis or metabolism of NO in endothelial cells are involved in CVD pathogenesis. It is well established that hypoxia is both the triggering factor as well as the accompanying factor...
-
Morphology changes in Fe-Cr porous alloys upon high-temperature oxidation quantified by X-ray tomographic microscopy
PublicationThe effect of high-temperature oxidation at 850 C (10 h, 30 h, 100 h) and 900 C (10 h) on porous (30 % porosity) ferritic stainless steel (Fe22Cr) has been investigated using synchrotron tomographic microscopy, which allowed for visualisation, separation and quantitative analysis of the metallic core, closed pores, open pores and oxide scale phase. The same regions within the samples were investigated before and after oxidation...
-
Preliminary Results from the Removal of Phosphorus Compounds with Selected Sorption Material
PublicationDue to the resources of phosphorous are limited and are exhausted in the next 30 years the management of the resources is become current issue. Most of the phosphorus compounds is lost forever, because it is discharged with sewage into surface waters, causing eutrophication and in this way causing a further problem and challenge. On the other hand, there is a considerable need for phosphorus compounds, primarily in bioavailable...
-
Micro-cracking pattern recognition of hybrid CNTs/GNPs cement pastes under three-point bending loading using acoustic emission technique
PublicationThe generation of microcracks has an important influence on the behaviour of concrete structures. In this study, the acoustic emission (AE) technique was used to investigate the fracture phenomena and micro-cracking behavior of hybrid carbon nanotubes (CNTs, the 1-D allotrope of carbon atoms) and graphene nanoplatelets (GNPs, 2D monolayer of sp2-hybridized carbon atoms), cement composites under three-point bending loading. In...
-
Protonic Ceramic Fuel Cells as novel electrochemical devices
PublicationProton ceramic conductors are novel materials which are interesting from the application point of view. For example, Protonic Ceramic Fuel Cells (PCFCs) is a type of a solid oxide fuel cell, which uses proton ceramic conductors as an electrolyte. Scientists are looking for the most efficient materials for these devices. In recent years main focus has been put on the search for new proton and mixed proton-electron conductors which...
-
Donor-substituted SrTi1+xO3−δ anodes for SOFC
PublicationNonstoichiometric Nb-substituted SrTiO3 compounds were investigated in order to discuss the influence of nonstoichiometry at the sample properties in the light of recent results reported in the literature. Structural and electrical properties of samples were characterized. Investigated compounds were also applied as anodes for Solid Oxide Fuel Cells and their reactivity with YSZ electrolyte was examined. The defect chemistry explaining...
-
Determining the leakage current resistive component by the orthogonal vector method
PublicationThe measurement of the metal – oxide surge arresters (MOSA) leakage current and the analysis of its components is a key diagnostic criterion according to technical standards. During on site MOSA condition assessment, the easy way is based on the measurement only leakage current, without the inconvenient live working measurements of supply voltage. Orthogonal vectors method of determination the resistive leakage current is presented....
-
Improvement of microstructure and mechanical properties of high dense sic ceramics manufactured by high-speed hot pressing
PublicationNon-oxide ceramics possess high physical-mechanical properties, corrosion and radiation resistance, which can be used as a protective materials for radioactive wastes disposal. The aim of the present study was the manufacturing of high density SiC ceramics with advanced physical and mechanical parameters. The high performance on the properties of produced ceramics was determined by the dense and monolithic structure. The densified...
-
Synchrotron radiation photoemission spectroscopy of the oxygen modified CrCl3 surface
PublicationWe investigate the experimentally challenging CrCl3 surface by photon energy dependent photoemission (PE). The core and valence electrons after cleavage of a single crystal, either in a ultrahigh vacuum (UHV) or in air, are studied by keeping the samples at 150 1C, aiming at confirming the atomic composition with respect to the expected bulk atomic structure. A common spectroscopic denominator revealed by data is the presence of...
-
Fabrication and structural properties of Y and Fe co-doped SrTiO3 nanoceramics for SOFC
PublicationYttria and iron co-doped strontium titanate perovskites, (Y0,07Sr0,93Ti1-xFexO3-δx=0,1; 0,2) samples were fabricated by two methods: solid-state synthesis (SS) and the Pechinisol-gel modified method. The morphology of samples were measured by SEM and X-raydiffraction. Results were compared and discussed. The strong relationship between fabricationprocedure and microstructure has been proven. It was also observed, that the nanoceramicsobtained...
-
EFFECT OF SURFACE STATE AND STRESS ON AN OXIDATION OF THE ZIRCALOY-2 ALLOY
PublicationZr alloys are widely used as materials for nuclear fuel pellets in the nuclear industry. In the case of the LOCA or RIA happen, a temperature may locally reach high values. Even if the high temperature maintains shortly, the zirconium oxides may become permeable, absorb hydrogen appearing in cooling water from decomposition reaction and crack because of formation and brittle failure of hydrides. Such model cannot so far take into...
-
Endothelial dysfunction due to eNOS uncoupling: molecular mechanisms as potential therapeutic targets
PublicationNitric oxide (NO) is one of the most important molecules released by endothelial cells, and its antiatherogenic properties support cardiovascular homeostasis. Diminished NO bioavailability is a common hallmark of endothelial dysfunction underlying the patho‑ genesis of the cardiovascular disease. Vascular NO is synthesized by endothelial nitric oxide synthase (eNOS) from the substrate L‑arginine (L‑Arg), with tetrahydrobiopterin...
-
Warstwy funkcjonalne tlenkowych ogniw paliwowych
PublicationIn this paper, results describing current research on solid oxide fuel cells conducted at Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics are presented. The results are related to three kinds of functional layers: a thin cathode layer between the porous cathode layer and the electrolyte to improve the cathode performance, a buffer layer between the electrolyte and the cathode to slow...
-
Application of multisine nanoscale impedance microscopy to heterogeneous alloy surface investigations
PublicationIn the recent years atomic force microscopy is recognized as valuable tool for investigation of surficial features of construction materials. It concerns, among other things, studies of changes caused by such phenomena as galvanic corrosion, passivation associated with the growth of oxide layers, or sensitization of austenitic steels with the formation of carbide phases. In addition, atomic forcemicroscopy allows easy coupling...
-
Effect of the Post-Weld Surface Condition on the Corrosion Resistance of Austenitic Stainless Steel AISI 304
PublicationSurfaces of welded elements made of corrosion-resistant (stainless) steels develop temper colours. The removal of thickened oxide layers off steels exposed to temperatures below 300°C is necessary and entails the restoring of high corrosion resistance of the stainless steel. The article presents tests concerned with the effect of a method applied to remove post-weld temper on the corrosion resistance of austenitic stainless steel...
-
Electrochemically directed biofunctionalization of a lossy-mode resonance optical fiber sensor
PublicationIn this work, we present a direct electrochemical biofunctionalization of an indium-tin-oxide-coated lossy-mode resonance optical fiber sensor. The functionalization using a biotin derivative was performed by cyclic voltammetry in a 10 mM biotin hydrazide solution. All stages of the experiment were simultaneously verified with optical and electrochemical techniques. Performed measurements indicate the presence of a poly-biotin...
-
Insightful Analysis of Phenomena Arising at the Metal|Polymer Interphase of Au-Ti Based Non-Enzymatic Glucose Sensitive Electrodes Covered by Nafion
PublicationThis paper focuses on the examination of glucose oxidation processes at an electrode material composed of gold nanoparticles embedded in a titanium template. Three dierent conditions were investigated: the chloride content in the electrolyte, its ionic conductivity and the presence of a Nafion coating. The impact of the provided environment on the oxidation reaction was evaluated by cyclic voltammetry (CV) and electrochemical impedance...
-
Application of the neural networks for developing new parametrization of the Tersoff potential for carbon
PublicationPenta-graphene (PG) is a 2D carbon allotrope composed of a layer of pentagons having sp2- and sp3-bonded carbon atoms. A study carried out in 2018 has shown that the parameterization of the Tersoff potential proposed in 2005 by Ehrhart and Able (T05 potential) performs better than other potentials available for carbon, being able to reproduce structural and mechanical properties of the PG. In this work, we tried to improve the...
-
Study of a Multicriterion Decision-Making Approach to the MQL Turning of AISI 304 Steel Using Hybrid Nanocutting Fluid
PublicationThe enormous use of cutting fluid in machining leads to an increase in machining costs, along with different health hazards. Cutting fluid can be used efficiently using the MQL (minimum quantity lubrication) method, which aids in improving the machining performance. This paper contains multiple responses, namely, force, surface roughness, and temperature, so there arises a need for a multicriteria optimization technique. Therefore,...
-
A Comprehensive Survey on Antennas On-Chip Based on Metamaterial, Metasurface, and Substrate Integrated Waveguide Principles for Millimeter-Waves and Terahertz Integrated Circuits and Systems
PublicationAntennas on-chip are a particular type of radiating elements valued for their small footprint. They are most commonly integrated in circuit boards to electromagnetically interface free space, which is necessary for wireless communications. Antennas on-chip radiate and receive electromagnetic (EM) energy as any conventional antennas, but what distinguishes them is their miniaturized size. This means they can be integrated inside...
-
Preparation and structure of nanocrystalline sol-gel derived Cu doped LiTi2O4 powders
PublicationAmong the spinel oxides materials, lithium titanate (Li1+xTi2-xO4 where 0 ≤ x ≤ 0.33) could be very interested from pratical applications point of view. Lithium titanate is a II type spinel oxide superconductor with relatively high (~13 K for x = 0) superconducting transition temperature Tc. Above Tc lithium titanate shows metallic behaviour and can be used e.g. as electrodes for rechargeable lithium-ion batteries. Since the discovery...
-
Experimental study on the effect of selected sterilization methods on mechanical properties of polylactide FFF specimens
PublicationPurpose: Biodegradable polymers are widely used in personalized medical devices or scaffolds for tissue engineering. The manufacturing process should be finished with sterilization procedure. However, it is not clear how the different sterilization methods have an impact on the mechanical strength of the three-dimensional (3D)-printed parts, such as bone models or personalized mechanical devices. This paper aims to present the...
-
Cement kiln dust
PublicationThe volume of cement production in the world has remained at the level of approxi mately 4.1 billion tons/year. The cement production process is energy intensive and is the world’s leading emitter of carbon dioxide. Therefore, the main activities cement plants are aimed at introducing technologies changes in production of clinkier.The construction industry is responsible for the majority of CO2 emissions to the atmosphere: the...
-
Photoelectric properties of a novel MEH-PPV/F16ZnPc heterojunction
PublicationPhotoelectric properties of a novel poly[2-methoxy-5-(2-ethylhexyloxy-p-phenylenevinylen)] (MEH-PPV)/perfluorozincphthalocyanine (F16ZnPc) planar heterojunction provided with BCP and MoO3 buffer layers sandwiched between indium tin oxide (ITO) and Ag are shown. Efficient photogeneration of charge carriers at this junction is observed. Effect of bathocuproine (BCP) and MoO3 buffer layers on the performance of cells is analysed....
-
Electrical properties of hybrid planar diode based on palladium phthalocyanine and titanium dioxide
PublicationThis work details experimental studies of a planar diode made of indium tin oxide/titanium dioxide/palladium phthalocyanine/gold. The rectification ratio of current was 105 at 1.5 V. The analysis of the electrical properties of the system was based on small signal complex capacitance spectra measured in the frequency range of 25 Hz-1 MHz at different values of bias. No depletion region at the TiO2/PdPc interface was observed. Forward...
-
Impedance Studies of Phosphate-iron Glasses Containing Niobium and Titanium
PublicationThe ac and dc conductivity in phosphate-iron-niobate glasses with addition of titanium oxide was investigated as a function of temperature and frequency with the use of impedance spectroscopy. The topography and microstructure of glasses were investigated by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and confocal microscopy methods. The obtained results show that all samples are amorphous but they...
-
Phase Separation and Electrical Properties of Manganese Borosilicate Glasses
PublicationThe structure and electrical properties of manganese borosilicate glasses of a composition of xMnO-(0.8-x)SiO2-(0.2)B2O3 (x=0.4, 0.5 and 0.6 in mol) were investigated by impedance spectroscopy, SEM, XRD and confocal microscopy methods. The influence of composition on the glass structure and electrical properties was discussed. A separation of two amorphous phases was observed and it was concluded that one phase is SiO2-rich and...
-
Methods of ZnO nanoparticles synthesis
PublicationZinc oxide nanostructures are interesting nanomaterials with a wide range of applications. Since the physical and chemical properties of ZnO nanoparticles are influenced both by their shape and size, a control of morphology of ZnO structures is needed for their commercial usage. Different chemical, physical, and biological methods used to produce ZnO nanostructures can be found in the literature. The production of ZnO nanoparticles...
-
Multi-layered tissue head phantoms for noninvasive optical diagnostics
PublicationExtensive research in the area of optical sensing for medical diagnostics requires development of tissue phantoms with optical properties similar to those of living human tissues. Development and improvement of in vivo optical measurement systems requires the use of stable tissue phantoms with known characteristics, which are mainly used for calibration of such systems and testing their performance over time. Optical and mechanical...
-
Elicitation strategies for the improvement of essential oil content in Rhododendron tomentosum (Ledum palustre) bioreactor-grown microshoots
PublicationRhododendron tomentosum Harmaja, previously Ledum palustre L., is a fragrant plant growing in swampy areas, which is characterized by well-known repellent properties and the anti-arthritic potential. In the present study, R. tomentosum microshoots cultivated in RITA® bioreactor, providing the alternative, environment-independent source of the valuable essential oil, were treated for 7 days with copper and nickel salts, methyl jasmonate,...
-
Electrodes criticality: the impact of CRMs in the leachate electrochemical oxidation
Publication. Landfill leachate possesses high concentrations of ammonia, micropollutants, and heavy metals, and are characterised for low biodegradability. For this reason, conventional treatment technologies may result ineffective for complete pollutant removal. Electrochemical oxidation allows most of the of recalcitrant pollutants to be oxidised effectively within an easy operational and acceptable retention time, without the need to provide...