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Search results for: femtosecond pulses
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Widening of the electroactivity potential range by composite formation – capacitive properties of TiO2/BiVO4/PEDOT:PSS electrodes in contact with an aqueous electrolyte
PublicationComposites based on the titania nanotubes were tested in aqueous electrolyte as a potential electrode material for energy storage devices. The nanotubular morphology of TiO2 was obtained by Ti anodization. TiO2 nanotubes were covered by a thin layer of bismuth vanadate using pulsed laser deposition. The formation of the TiO2/BiVO4 junction leads to enhancement of pseudocapacitance in the cathodic potential range. The third component,...
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SIGNIFICANT GUIDELINE FOR THE DAMAGE INDICES APPLIED TO REINFORCED CONCRETE STRUCTURES
PublicationIn this paper, based on a deep overview and literature study, the different formulas proposed for damage indices (DIs) applied to reinforced concrete structures under monotonic or cyclic loading are classified and presented. The DIs are applied to quantify the damages to structures, ranging from zero to one. Normally, they are applied to make a decision for repairing or demolition of the structures in the post-earthquake phases. Keywords:...
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Influence of span length and impulse front time on earthing measurement accuracy of power line towers
PublicationThe article discusses the issue of measuring and assessing the features of power line tower earthings using fast-changing waveform. The study analyses the effect of impulse front time and the line span length on errors made during these measurements using impulse meters. It has been found that the assessment conditions similar to the static measurement results occur for the use of 4 μs current impulses and such procedure is useful...
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Life cycle theories of savings and consumption
PublicationLife cycle theories of savings and consumption are the economics theories explaining the changes in saving and consumption in the subsequent phases of the human life cycle. There are two main approaches: (1) indicating the dependence of the level of savings and consumption on the average level of income over a long period of human life (life cycle hypothesis; LCH) or (2) on psychological factors, in particular self-control and...
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Searching of the buried objects into the sea bottom by means of nonlinear acouctic methods
PublicationThe main goal of this paper is to introduce the methodology of preparing the area for investigations that will be carried out at the sea. As the first step there is recognition of the basic method both in the theory as well as experimental investigation. There were taken into account the nonlinear methods. These ones are very promising methods that have very interesting features, very convenient for examinations of the seabed structure....
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Low energy electron attachment to platinum(II) bromide (PtBr2)
PublicationtDissociative electron attachment to PtBr2in the gas phase was studied in the low electron energy rangefrom zero up to 10 eV with an energy resolution of 150 meV. The experiments were carried out using ahemispherical electron monochromator coupled with a quadrupole mass spectrometer and pulse count-ing acquisition system. The only anion observed was Br−. This ion is formed at three resonance electronenergies: 0.4 eV, 1.2 eV and...
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An Implementation of a Compact Smart Resistive Sensor Based on a Microcontroller with an Internal ADC
PublicationIn the paper a new implementation of a compact smart resistive sensor based on a microcontroller with internal ADCs is proposed and analysed. The solution is based only on a (already existing in the system) microcontroller and a simple sensor interface circuit working as a voltage divider consisting of a reference resistor and the resistive sensor connected in parallel with an interference suppression capacitor. The measurement...
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Application of Barycentric Coordinates in Space Vector PWM Computations
PublicationThis paper proposes the use of barycentric coordinates in the development and implementationof space-vector pulse-width modulation (SVPWM) methods, especially for inverters with deformed space-vector diagrams. The proposed approach is capable of explicit calculation of vector duty cycles, independentof whether they assume ideal positions or are displaced due to the DC-link voltage imbalance. The use ofbarycentric coordinates also...
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Modeling and Evaluation of Electric Treeing Phenomena in Polymeric Cable Insulation
PublicationThis paper investigates the treeing phenomenon in polymeric materials such as crosslinked polyethylene (XLPE) that is widely used in medium and high voltage power cables as primary insulation. The modeling of electrical tree growth in the insulation from its initiation to breakdown is significant research work that illustrates the discharge dynamics and its impact on aging process in polymeric insulation. This study utilizes pulse...
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Nitrogen-Incorporated Boron-Doped Nanocrystalline Diamond Nanowires for Microplasma Illumination
PublicationThe origin of nitrogen-incorporated boron-doped nanocrystalline diamond (NB-NCD) nanowires as a function of substrate temperature (Ts) in H2/CH4/B2H6/N2 reactant gases is systematically addressed. Because of Ts, there is a drastic modification in the dimensional structure and microstructure and hence in the several properties of the NB-NCD films. The NB-NCD films grown at low Ts (400 °C) contain faceted diamond grains. The morphology...
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Compatibility of Sustainable Mater-Bi/poly(ε-caprolactone)/cellulose Biocomposites as a Function of Filler Modification
PublicationDespite their popularity and multiplicity of applications, wood–polymer composites (WPCs) still have to overcome particular issues related to their processing and properties. The main aspect is the compatibility with plant-based materials which affects the overall performance of the material. It can be enhanced by strengthening the interfacial adhesion resulting from physical and/or chemical interactions between the matrix and...
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Mechanical and structural behavior of high-strength low-alloy steel pad welded by underwater wet welding conditions
PublicationThe aim of the paper was to determine the metallurgical and mechanical behaviors of a high-strength low-alloy (HSLA) steel pad-welded specimen used in the structures of industrial and naval parts. Then to predict the metallurgical consequences (nature of the phases present) and the mechanical properties (hardness and impact strength) of the pad-welded steel obtained by underwater wet welding with different heat input values. The...
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Two-photon perimetry utilizing picosecond laser
PublicationAge-related impairments are becoming more and more severe for aging societies. The sensory organ diseases are particularly troublesome as they exclude seniors from their everyday activity. Therefore, maintaining good quality eyesight is essential for normal functioning. New medical therapies help restrain age-related changes, but still, monitoring is essential to the treatment process. Humans do not have the natural ability to...
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Nanostructuring of thin Au films deposited on ordered Ti templates for applications in SERS
PublicationIn this work the results on thermal nanostructuring of the Au films on Ti templates as well as morphology and optical properties of the obtained structures are reported. The bimetal nanostructures are fabricated in a multi-step process. First, the titania nanotubes are produced on the surface of Ti foil by anodization in an ethylene glycol-water solution containing fluoride ions. This is followed by chemical etching in oxalic acid...
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Porównanie działania transformatora symetryzującego (zygzak) z aktywnym energoelektronicznym symetryzatorem prądów fazowych linii niskiego napięcia
PublicationNa potrzeby planowania sieci niskiego napięcia operatorzy systemów dystrybucyjnych (OSD) zakładają symetryczne warunki obciążenia linii. Z roku na rok, rośnie liczba rozproszonych systemów fotowoltaicznych (PV) zainstalowanych w sieciach niskiego napięcia, których większość to małe jednofazowe systemy dachowe. Dodatkowo, do niesymetrii obciążenia przyczyniają się instalowane masowo pompy ciepła i ładowane jednofazowo samochody...
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Analysis of compressive forces in CFGFT cylindrical pillars and their coatings using laboratory tests and metric spaces
PublicationThe article discusses compressive forces tests in composite-concrete pillars with the use of laboratory active experiment including the factors and properties of materials which have a significant impact on the test results and their repeatability. A polymer composite based on glass fiber reinforced resin with different fiber beam angles (20, 55 and 85) was used as a buffer/coat of the pole. Due to the problems with direct comparison...
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Regularized Local Multivariate Reduced-Order Models With Nonaffine Parameter Dependence
PublicationThis paper addresses a singular problem, not yet discussed in the literature, which occurs when parametric reduced-order models are created using a subspace projection approach with multiple concatenated projection bases. We show that this technique may lead to the appearance of localized artifacts in the frequency characteristics of a system, even when the reduced-order projection basis is rich enough to describe the original...
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Pressure pulsations in turbine blade seal clearance
PublicationThe paper presents the results of numerical and experimental investigations into pressure forces generated in a turbine labyrinth seal. The experiments were performed on a single-stage air model turbine of the impulse type, while the numerical results were obtained by means of CFD Fluent Code. The performed experimental research and numerical calculations prove that in a shroud clearance the pressure pulsates and the effects of...
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Analysis of the image force effects on the recombination at the donor-acceptor interface in organic bulk heterojunction solar cells
PublicationWe consider the influence of image force effects on the recombination at the donor-acceptor interface in organic bulk heterojunction solar cells. The conclusion is that the charge carriers of one sign located in the material with lower permittivity recombine at the boundary between donor and acceptor phases. This process competes with the recombination of opposite sign charge carriers, leading to the reduction of the Langevin-type...
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Nongeminate recombination in organic bulk heterojunction solar cells: Contribution of exciton–polaron interaction
PublicationA new model to explain nongeminate recombination in organic bulk heterojunction solar cells is presented. We suggest that the annihilation of excitons on charge carriers at the interface between donor and acceptor phases competes with the bimolecular recombination of Coulombically bound electron–hole pairs. The exciton–polaron interaction gives visible contribution to the reduction of Langevin recombination. An analytical formula,...
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Engineer's graphic workshop. Historical review.
PublicationThe paper introduces the history of development of graphic engineering workshop within European culture. The fundamentals of scientific approach to this subject are dated back to the XVIII century. Owning to Gaspard Monge's works descriptive geometry rose to the rank of branch of mathematics. As the time passes we observe the endeavors aiming at accelerating and automating the process of engineering drawing. Since the XX century...
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Inverse heat transfer problem solution of sounding rocket using moving window optimization
PublicationAn Inverse Heat Transfer Problem is solved for a sounding rocket module given its geometry and measured temperature profile. The solution is obtained via moving window optimization, a technique for solving inverse dynamics. An analysis is performed to modify the method to avoid oscillatory behavior of the resulting heat flux profile. The method parameters are tuned in relation to characteristic phases of the flight. Results are...
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Acoustic radiation force and streaming caused by non periodic acousticsource.
PublicationTeoria i obliczenia numeryczne przepływu rotacyjnego (''streamingu'') towarzyszącemu fali akustycznej w przepływach lepkich nieliniowych. Fala wywołująca może być nieokresowa: impulsowa lub paczka falowa itd. Przykład pojedynczego pulsu rozpatrywany. Ilustracje delikatnej struktury czasowej powstania fal rotacyjnych przedstawione na rysunkach.
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Reflektancyjny pulsoksymetr mocowany na klatce piersiowej
PublicationPulsoksymetria to nieinwazyjna i nowoczesna metoda badania wysycenia krwi tlenem oraz pulsu. Istnieją dwie metody pomiaru: transmisyjna i reflektacyjna, różniące się wzajemnym położeniem źródła światła i fotodetektora. Niniejszy artykuł przedstawia pierwszą fazę projektu reflektancyjnego pulsoksymetru mocowanego na klatce piersiowej.
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The Economic Legacy of Mega Sporting Events. The Impact of Hosting European Olympic Games on GDP Growth Through Infrastructure Development
PublicationIntroduction. The positive legacy of the Olympics is often cited by the International Olympic Committee and national or-ganizers. Some scholars, however, question an uncritical approach to an exclusively positive economic legacy. The aim of this study is to evaluate the impact of hosting the Olympics on infrastructure development, with a potential impact on economic growth in the form of Gross Domestic Product (GDP) in three phases...
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Tuning the ferromagnetic phase in the CDW compound SmNiC2 via chemical alloying
PublicationWe report a study on tuning the charge density wave (CDW) ferromagnet SmNiC2 to a weakly coupled superconductor by substituting La for Sm. X-ray diffraction measurements show that the doped compounds obey Vegard’s law, where La (Lu) alloying expands (shrinks) the lattice due to its larger (smaller) atomic size than Sm. In the series Sm1−xLaxNiC2, CDW transition (TCDW =148K) for SmNiC2 is gradually suppressed, while the ferromagnetic...
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Compact Electromagnetic Lens Antennas Using Cascaded Metasurfaces for Gain Enhancement and Beam Steering Applications
PublicationElectromagnetic (EM) lens antenna designs using cascaded metasurfaces for gain enhancement and beam steering applications are proposed. Two different lens aperture designs are proposed and populated with aperiodic unit cells of size 0.2λo × 0.2λo. In lens Design 1, the unit cells of different phases are distributed in concentric circular zones, whereas in lens Design 2, the unit cells of different phases are distributed in vertical...
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Functionalization of indium-tin-oxide electrodes by laser-nanostructured gold thin films for biosensing applications
Publicationof a relatively large area formed by pulsed laser nanostructuring of thin gold films arereported and discussed. The SEM inspection of modified electrodes reveals the presence of the nearlyspherical and disc-shaped particles of dimensions in the range of 40–120 nm. The NP-array geometry canbe controlled by selection of the laser processing conditions. It is shown that particle size and packingdensity of the array are important factors...
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The bismuth vanadate thin layers modified by cobalt hexacyanocobaltate as visible-light active photoanodes for photoelectrochemical water oxidation
PublicationBismuth vanadate thin films deposited using the pulsed laser deposition technique were modified using cobalt hexacyanocobaltate (Cohcc). The 2-step method of Cohcc nanocubes preparation was applied: i) metallic cobalt deposition and ii) cobalt electrooxidation in Co(CN)63− containing electrolyte. The presence of CN stretching vibrations was confirmed by Raman spectroscopy. The energy band gap was equal to 2.5 eV and was estimated...
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On the synthesis of coupled-lossy resonator filters with unloaded quality factor control
PublicationA technique for fast synthesis of coupling matrix low-pass prototypes of generalized Chebyshev bandpass filters with lossy resonators is presented in this paper. The coupling matrix is found by solving a nonlinear least squares problem based on zeros and poles of filter's transfer functions. Additional constraints are introduced that allow one to control the level of unloaded quality factor of resonators.
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Low-Cost Surrogate Models for Microwave Filters
PublicationA novel low-cost kriging-based multivariable parametric macromodeling technique for microwave filters is presented. Kriging is used to model both the residues and poles of a microwave filter's reflection coefficient, and the zeros of the transmission coefficient. The proposed residue-pole-zero (RPZ) technique is demonstrated to efficiently model a high dimensional (8D) microwave filter with pseudoelliptic characteristics.
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Proposed Amendments to Reactive Energy Billing
PublicationThis paper describes possible amendments to the rules of reactive energy billing in the tariffs in Poland. Modifications in the tariffs to improve their motivational function for distribution system users are identified as the most expedient. New problems arising from distributed generator operations are also indicated. A billing method that can be effectively implemented at the occurrence of distorted voltage and current waveforms...
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Sounding of Layered Marine Bottom - Model Investigations
PublicationThe necessary actions connected with interpretations of examining of physical properties of sea bottom structure is developing of proper procedure of modeling of the layered structure. The implementation of the acoustic waves for the determination of seabed stratification requires a precise diagnosis of the topic from both the theoretical and practical side. Little differences between the parameters of sediments, as well as irregular...
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Single-phase, Five-level Inverter with SPWM-Based Neutral Point Voltage Balancing Scheme
PublicationMultilevel inverter topologies provide several advantages over two-level inverter configuration. These benefits are the reason for the growing interest in multilevel topologies among research society. One of the most popular topological concepts (diode and active switch clamping) requires neutral-point potential balancing due to series-connected capacitor banks across the input dc link in such derived inverter configurations. This...
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Performance Comparison of a 650 V GaN SSFET and CoolMOS
PublicationThe new technology of wide band gap semiconductors is said to outperform up-to-date silicon devices. High voltage Gallium Nitride (GaN) transistors, now emerging in the market, have even three times shorter switching times and even four times smaller energy losses compared to the best in-class Si devices. In this paper the performance of a 650 V GaN SSFET is evaluated and compared with the newest silicon family of CoolMOS™ technology....
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Emotion Monitoring – Verification of Physiological Characteristics Measurement Procedures
PublicationThis paper concerns measurement procedures on an emotion monitoring stand designed for tracking human emotions in the Human-Computer Interaction with physiological characteristics. The paper addresses the key problem of physiological measurements being disturbed by a motion typical for human-computer interaction such as keyboard typing or mouse movements. An original experiment...
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A Power-Efficient Digital Technique for Gain and Offset Correction in Slope ADCs
PublicationIn this brief, a power-efficient digital technique for gain and offset correction in slope analog-to-digital converters (ADCs) has been proposed. The technique is especially useful for imaging arrays with massively parallel image acquisition where simultaneous compensation of dark signal non-uniformity (DSNU) as well as photo-response non-uniformity (PRNU) is critical. The presented approach is based on stopping the ADC clock by...
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A Direct Modulation for Matrix Converters based on the Onecycle Atomic operation developed in Verilog HDL.
PublicationThis paper presents a fast direct Pulse Width Modulation (PWM) algorithm for the Conventional Matrix Converters (CMC) developed in Verilog Hardware Description language (HDL). All PWM duty cycle calculations are performed in one cycle by an atomic operation designed as a digital module using FPGA basic blocks. The algorithm can be extended to any number of output phase. The improved version of the discontinuous Direct Analytic...
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Modeling the impact of rotor movement on non-linearity of motor currents waveforms in high-speed PMSM drives
PublicationMotor current measurement techniques as well as predictive control algorithms for electric drives rely on an assumption of linear motor currents changes resulting from constant inverter output voltages. Recent research has reported that this assumption does not hold in motors with short electrical time constant, and in drives whose rotor position advances substantially during a control period. This paper proposes a simulation model...
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Dynamic Nanoimpedance Characterization of the Atomic Force Microscope Tip-Surface Contact
PublicationNanoimpedance measurements, using the dynamic impedance spectroscopy technique, were carried out during loading and unloading force of a probe on three kinds of materials of different resistivity. These materials were: gold, boron-doped diamond, and AISI 304 stainless steel. Changes of impedance spectra versus applied force were registered and differences in the tip-to-sample contact character on each material were revealed. To...
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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...
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Tax Policy Tools of Selected European Countries as a Mechanism for Counteracting the Effects of the Crisis Caused by the COVID-19 Disease Pandemic
PublicationCrises play an important role in a economics life. They are common and it is impossible to omit them. This following study investigates the concept of ‘crisis’ in the context of economic situation. This text describes the most important financial crises that took place in the past. After that authors passes on a detailed analysis of the actual corona-crisis and the way that it affects the economy globally. The main goal of this...
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Nowe rozwiązania metodyczne i techniczne w zakresie techniki mikroekstrakcji do fazy stracjonarnej
PublicationSample preparation has been recognized as a critical step of the analytical process, being even considered as the bottleneck of the overall process. Enrichment of target compounds, transfer of the analytes into a solvent compatible with the analytical instrumentation, minimization of potential interferences, and efficient sample clean-up, are among the main aims of sample preparation techniques. In this regard, liquid-liquid extraction...
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Comparison of safety levels required by adequate regulations for cargo ships of different types
PublicationDuring the currently ongoing development of methods for assessing the safety of ships, it is imperative that a compromise between the accuracy of the results and the accessibility of obtaining results is reached. This paper shows the calculations of a theoretical hull against damage stability regulations as included in SOLAS 2020, ICLL 66/88 as amended in 2003 and MARPOL 78. The rules included in the currently valid regulations require...
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Pile Model Tests Using Strain Gauge Technology
PublicationOrdinary pile bearing capacity tests are usually carried out to determine the relationship between load and displacement of pile head. The measurement system required in such tests consists of force transducer and three or four displacement gauges. The whole system is installed at the pile head above the ground level. This approach, however, does not give us complete information about the pile-soil interaction. We can only determine...
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Formowanie wektorów napięcia wyjściowego w pięciofazowych falownikach napięcia
PublicationW falownikach pięciofazowych, załączenie wektorów aktywnych powoduje jednoczesne formowane dwóch, zależnych od siebie wektorów napięcia wyjściowego. Sterowanie pięciofazowymi silnikami indukcyjnymi wymaga, aby wektory te miały ściśle określone długości i położenia. Niezależne formowanie dwóch wektorów napięcia o parametrach określonych w układzie sterowania silnikiem wymaga zastosowania odpowiedniej strategii Modulacji Szerokości...
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CGO FILMS ON YSZ ELECTROLYTE FABRICATED BY SPRAY PYROLYSIS FOR SOFC
PublicationINTRODUCTION Solid oxide fuel cells are one of the fastest developing energy converters. The advancement introduced by research community provides steady state progress is stability and performance of the fuel cells. Significant influence on the cell’s performance and stability is related to cell design. The simplest design just consists of an anode, a solid electrolyte and a cathode. However, in order to improve the properties,...
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Electrical properties and structure of lead-borate glass containing iron ions.
PublicationThe ac and dc conductivity in iron–lead-borate glass samples was investigated in the frequency range from 1 mHz to 1 MHz and in the temperature range from 153 K to 423 K. The structure was investigated by the means of atomic force microscopy (AFM) and the crystalline phases (if present) were identified by the means of X-ray diffractometry. Two types of ac electrical behaviour were observed. The first group of glass samples which...
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Thermal degradation of polylactic acid (PLA)/polyhydroxybutyrate (PHB) blends: A systematic review
PublicationPolylactic acid (PLA) and polyhydroxybutyrate (PHB) are two biopolyesters obtained from renewable resources like corn or sugar under bacterial fermentation. PLA is the most widely used biopolymer in diverse applications. Addition of PHB to PLA can improves the crystallinity of PLA, and thereby its mechanical strength. However, both PLA and PHB suffer from poor thermal stability, which limits their potential industrial application....
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Plant-based meat substitute analysis using microextraction with deep eutectic solvent followed by LC-MS/MS to determine acrylamide, 5-hydroxymethylfurfural and furaneol
PublicationFor the analysis of plant-based meat substitutes and the determination of Maillard reaction products such as acrylamide, 5-hydroxymethylfurfural and furaneol, a novel and effective procedure based on hydrophobic natural deep eutectic solvent and liquid chromatography coupled with tandem mass spectrometry was developed for the first time. The 49 compositions of the deep eutectic solvents were designed and screened to select the...