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Search results for: transmission electron microscopy
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The Influence of Laser Alloying of Ti13Nb13Zr on Surface Topography and Properties
PublicationThe laser alloying is a continually developing surface treatment because of its significant and specific structuration of a surface. In particular, it is applied for Ti alloys, being now the most essential biomaterials` group for load-bearing implants. The present research was performed on the Ti13Nb13Zr alloy subject to laser modification in order to determine the treatment effects on surface topography and its some mechanical...
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Adaptive Method of Raster Images Compression and Examples of Its Applications in the Transport Telematic Systems
PublicationThe paper presents a concept and exemplary application of an adaptive method of compression of raster images which may be applied, i.a. in ITS systems. The described method allows to improve the efficiency of systems belonging to ITS category, which require transmission of large volumes of image data through telecommunications networks. The concept of the adaptive method of compression of raster images described in the paper uses...
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Optical properties of TeOx gels doped with a mix of rare-earth ions
Open Research DataThe DataSet contains the UV-Vis spectra of the TeOx gels doped with a mix of rare-earth ions. The material was obtained by the sol-gel method. The starting solution was prepared by mixing telluric acid (precursor) with thetraetylene glycol, water, and ethanol. Next, the different molar concentration of rare-earth ions was added, nitrates were used...
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Optical properties TeOx gels doped with the rare-earth ions
Open Research DataThe DataSet contains the UV-Vis spectra of TeOx gels doped with the rare-earth ions. The material was obtained by the sol-gel method. The starting solution was prepared by mixing telluric acid (precursor) with thetraetylene glycol, water, and ethanol. Next, the 5% mol of the rare-earth ions were added, the nitrates were used as a source of rare-earth...
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Au nanoparticles identifiction with the use of AFM Volta potential mapping
Open Research DataThe specific physical, chemical and electrochemical electrical properties of gold nanoparticles have led to their extensive use as high-performance chemical and biochemical sensors. The described properties relate to surface plasmon resonance, fluorescence quenching or enhancement, high electrical conductivity and light scattering. The described nanoparticles...
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Interaction of 4-nitrothiophenol with low energy electrons: Implications for plasmon mediated reactions
PublicationThe reduction of 4-nitrothiophenol (NTP) to 4-4′-dimercaptoazobenzene (DMAB) on laser illuminated noble metal nanoparticles is one of the most widely studied plasmon mediated reactions. The reaction is most likely triggered by a transfer of low energy electrons from the nanoparticle to the adsorbed molecules. Besides the formation of DMAB, dissociative side reactions of NTP have also been observed. Here, we present a crossed electron-molecular...
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Case studies of resonance phenomena in high voltage overhead power lines with shunt reactors
PublicationMisguided design of the towers of power transmission lines can lead to serious problems such as voltage asymmetry, overvoltages, electric arc extinction difficulties or resonance – in case of double circuit line with shunt reactors. The paper points out those threats on example of 400 kV double circuit overhead transmission line with shunt reactors.
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Kinga Kaniewska-Laskowska dr inż.
PeopleEducation BSc - qualification: Engineer in Chemistry 2013: Gdańsk University of Technology, Faculty of Chemistry, Department of Inorganic ChemistryPL thesis title: Kompleksy żelaza z ligandami fosfinidenowymiEN thesis title: Iron complexes with phosphinidene ligands Supervisor: dr hab. inż. Rafał Grubba MSc - qualification: Master of Science in Chemical Technology, spec. Organic Technology 2014: Gdańsk University of Technology,...
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Labellum and gynostemium micromorphology in Polystachya (Orchidaceae)
PublicationPolystachya is a large, pantropical orchid genus of 200 species, most of which occur as epiphytes in sub-saharan Africa. The three-lobed labellum of most Polystachya species possesses a fleshy callus and various types of trichomes and papillae. In this paper, we present the results of micromorphological studies on the labellum of 20 species, representing eight of the 13 sections in the genus, using scanning electron microscopy...
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Comparative Assessment of Bacteriophage and Antibiotic Activity against Multidrug-Resistant Staphylococcus aureus Biofilms
PublicationProblems connected with biofilm-related infections and antibiotic resistance necessitate the investigation and development of novel treatment strategies. Given their unique characteristics, one of the most promising alternatives to conventional antibiotics are bacteriophages. In the in vitro and in vivo larva model study, we demonstrate that phages vB_SauM-A, vB_SauM-C, and vB_SauM-D are effective antibiofilm agents. The exposure...
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Variations in host surfaces morphology and biology of ciliate epibionts explaining distribution pattern of epibionts in the invasive signal crayfish Pacifastacus leniusculus (Dana, 1852)
Publicationciliates on the signal crayfish Pacifastacus leniusculus in relation to specialized structures of the host’s exoskeleton for the first time. This species is known to maintain a relatively clean carapace, but it is sometimes overgrown by other organisms. Epibionts cover different parts of the signal crayfish body, mainly antennae, antennules, maxillipedes III and pereiopods with inner edges of chelae; however, some parts of the...
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Cyclic behavior of FeCoCrNiMn high entropy alloy coatings produced through cold spray
PublicationeCoCrNiMn high entropy alloy powders were employed to produce coatings on carbon steel through high pressure cold spray (at 1100 °C and 7 MPa in temperature and pressure respectively). X-ray diffraction of the sprayed material revealed a dense coating with the retention of the original crystallographic structure. Once splatted, particles revealed high flattening ratio with consequent excellent adhesion of the coating to the substrate....
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The Effect of Sodium Tetrafluoroborate on the Properties of Conversion Coatings Formed on the AZ91D Magnesium Alloy by Plasma Electrolytic Oxidation
PublicationMagnesium and its alloys are widely used in many areas because of their light weight, excellent dimensional stability, and high strength-to-weight ratio. However, the material exhibits poor wear and corrosion resistance, which limits its use. Plasma electrolytic oxidation (PEO) is an effective surface modification method for producing ceramic oxide layers on Mg and their alloys. The influence of the additions of sodium tetrafluoroborate...
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The Effect of Titanium Oxyfluoride Morphology on Photocatalytic Activity of Fluorine-Doped Titanium(IV) Oxide
PublicationTitanium oxyfluoride (TiOF2) is a metastable product that can be obtained in a fluorine-rich environment. This material can also be a valuable precursor in the synthesis of titanium(IV) oxide (TiO2). However, the effect of TiOF2 morphology on the physicochemical properties of TiO2 has not been studied so far. In this work, single-phase TiOF2 was prepared by a solvothermal method. The as-synthesized samples exhibited a variety of...
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Experimental review of the performances of protective coatings for interconnects in solid oxide fuel cells
PublicationFerritic stainless steel interconnects are used in solid oxide fuel cells; however, coatings are required to improve their performance. Although several types of coatings have been proposed, they have been scarcely investigated under similar conditions. This study compares the characteristics of uncoated Crofer 22 APU and eight different coatings on Crofer 22 APU for up to 3000 h at 800 ◦C. The coatings were deposited at various...
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Impact of low-temperature sintering on the Fe-based amorphous coatings
PublicationBulk 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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Cyclic deformation and fracture behaviour of additive manufactured maraging steel under variable-amplitude loading
PublicationThe cyclic deformation and fracture behaviour of 18Ni300 maraging steel produced by laser beam powder bed fusion is studied under variable-amplitude loading. The tests were conducted under fully-reversed strain-controlled conditions with a loading sequence comprising three ascending cycles and three descending cycles repeated sequentially until failure. After the tests, fracture surfaces were examined using height and volume surface...
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Impact of strontium non-stoichiometry of SrxTi0.3Fe0.7O3-δ on structural, electrical, and electrochemical properties for potential oxygen electrode of intermediate temperature solid oxide cells
PublicationThis work presents the results of a comprehensive study on the impact of the A-site non-stoichiometry of SrxTi0.3Fe0.7O3-δ (x = 0.90, 0.95, 1.00, 1.05) ceramics on their physicochemical properties. The materials were fabricated by the conventional solid-state reaction method and their structure was determined by X-ray diffractometry, X-ray photoelectron spectroscopy and electron microscopy. Their sintering and thermal expansion...
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Thermal, electrical, and magnetic properties of Fe2O3–PbO–SiO2 glass prepared by traditional melt-quenching and twin roller fast-cooling methods
PublicationIn this study, Fe–Pb–Si oxide glasses containing between 12.5 and 17.5 mol% Fe2O3 were prepared using two different methods comprising traditional melt-quenching and twin roller fast-cooling techniques. The topography and structure of the materials obtained were characterized by X-ray powder diffraction and scanning electron microscopy. All of the materials were found to be amorphous. The topography of most of the glasses comprised...
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Nanocrystalline diamond sheets as protective coatings for fiber-optic measurement head
PublicationFiber-optic sensors find numerous applications in science and industry, but their full potential is limited because of the risk of damaging the measurement head, in particular, due to the vulnerability of unprotected tips of the fiber to mechanical damage and aggressive chemical agents. In this paper, we report the first use of a new nanocrystalline diamond structure in a fiber-optic measurement head as a protective coating of...
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Theoretical and Experimental Studies on the Visible Light Activity of TiO2 Modified with Halide-Based Ionic Liquids
PublicationFormation of a surface complex between organic molecules and TiO2 is one of the possible strategies for the development of visible light-induced TiO2 photoactivity. Herein, three ionic liquids (ILs) with the same cation and dierent anions (1-butylpirydynium chloride/bromide/iodide) have been applied for the surface modification of TiO2 and to understand the role of anions in visible light-induced activity of ILs-TiO2 systems. Photocatalytic...
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In-situ odd random phase electrochemical impedance spectroscopy study on the electropolymerization of pyrrole on iron in the presence of sodium salicylate – The influence of the monomer concentration
PublicationIn this work, the potentiostatic electropolymerization of polypyrrole (PPy) on iron in aqueous solution of sodium salicylate and pyrrole is studied in situ by odd random phase electrochemical impedance spectroscopy (ORP-EIS). The influence of the pyrrole concentration on the electrosynthesis process is investigated. The ORP-EIS technique ensures a reliable analysis of the PPy electrosynthesis on iron by means of an advanced data...
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Enhanced photoelectrochemical performance of inorganic-organic hybrid consisting of BiVO4 and PEDOT:PSS
PublicationThe PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)) was electrodeposited on a thin layer of bismuth vanadate (BiVO 4 ) prepared using the pulsed laser deposition technique onto FTO. The inorganic-organic junction was characterized by Raman spectroscopy, UV-Vis spectroscopy and sc anning electron microscopy. Chronoamperometry curves, recorded under simulated solar light illumination,...
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Fabrication of La-Doped Bi4Ti3O12 Ceramics
PublicationLa-modified Bi4Ti3O12 is a typical ferroelectric, piezoelectric and electro-optic material, having relatively low coercive field, low dielectric constant, high Curie temperature and high breakdown strength. Goal of the present research was to apply mixed oxide method for fabrication of BiTLax ceramics, study its chemical composition, crystalline structure and microstructure. The compound BiTLax for x=0, 0.25, 0.5, 0.75 ceramic...
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The In-Depth Studies of Pulsed UV Laser-Modified TiO2 Nanotubes: The Influence of Geometry, Crystallinity, and Processing Parameters
PublicationThe laser processing of the titania nanotubes has been investigated in terms of morphology, structure, and optical properties of the obtained material. The length of the nanotubes and crystallinity, as well as the atmosphere of the laser treatment, were taken into account. The degree of changes of the initial geometry of nanotubes were checked by means of scanning electron microscopy, which visualizes both the surface and the cross-section....
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Electrochemical performance of thin free-standing boron-doped diamond nanosheet electrodes
PublicationIn the following work we describe preparation and the electrochemical performance of thin and free-standing heavy boron-doped diamond (BDD) nanosheets. The investigated foils were deposited on Ta substrate using microwave plasma-enhanced chemical vapor deposition technique (MPECVD). Foils of two B-dopant densities were investigated, obtained on the base of 10 k and 20 k ppm [B]/[C] ratio in the gas admixture. The obtained foils...
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Plasmon resonance in a TiO2-Au NPs structures
Open Research DataInvestigated structures were deposited on a pre cleaned Corning 1737 glass substrates, which provided flat optical transmission characteristics and high transmission coefficient in a visible light range. Plasmonic nanostructures were formed as a result of thermal annealing. For gold films with thickness of 2.8 nm depiction a table-top dc magnetron sputtering...
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LTE and NB-IoT Performance Estimation Based on Indicators Measured by the Radio Module
PublicationMonitoring the operating parameters of power grids is extremely important for their proper functioning as well as for ensuring the security of the entire infrastructure. As the idea of the Internet of Things becomes more ubiquitous, there are tools for monitoring the state of the complex electrical grid and means to control it. There are also developed new measuring devices and transmission technologies allowing for the transfer...
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Tuning of microstructure in engineered poly (trimethylene terephthalate) based blends with nano inclusion as multifunctional additive
PublicationImmiscible blends and their composites are heterogeneous and have variable morphology due to variation in mesophase regions. Tuning, i.e. controlling the phase dimension is important, thereof we report a “super-combo” effect of multiwalled carbon nanotubes (MWCNTs) in poly (trimethylene terephthalate)/polypropylene (PTT/ PP) blend system. MWCNTs act as a good reinforcing agent and compatibilizer in the otherwise immiscible PTT/...
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The effect of metal cluster deposition route on structure and photocatalytic activity of mono- and bimetallic nanoparticles supported on TiO2 by radiolytic method
PublicationTiO2 (P25) was modified with small and relatively monodisperse mono- and bimetallic clusters (Ag, Pd, Pt, Ag/Pd, Ag/Pt and Pd/Pt) induced by radiolysis to improve its photocatalytic activity. The as-prepared samples were characterized by X-ray fluorescence spectrometry (XRF), photoluminescence spectrometry (PL), diffuse reflectance spectroscopy (DRS), X-ray powder diffractometry (XRD), scanning transition electron microscopy (STEM)...
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Analiza wpływu transmisji danych na jakość działania rozproszonych systemów sterowania
PublicationW artykule przedstawiono zagadnienia związane z transmisją danych w rozproszonych systemach sterowania. Opisano cechy charakterystyczne przemysłowych sieci i protokołów informatycznych. Utworzono model rozproszonego systemu sterowania poziomem cieczy w zbiorniku, w którym komunikacja oparta została na protokole Modbus RTU. Na podstawie zmian parametrów transmisji danych wykazano, że poprawna komunikacja pomiędzy elementami systemu...
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Analysis of positioning error and its impact on high frequency properties of differential signal coupler
PublicationThis paper presents the analysis of the effect of differential signal coupler positioning accuracy on its high frequency performance parameters for contact-less high speed chip-to-chip data transmission on PCB application. Our considerations are continuation of the previous works on differential signal coupler concept, design methodology and analysis for high speed data transmission monitoring. The theoretical analysis of possible...
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Study of ultraviolet-visible fluorescence emission following resonant Auger decay of the 2p-1nl core-excited states of argon atoms
PublicationWe have studied the excitation and relaxation of Ar+ ions populated in resonant Auger decay from the Ar 2p−1nl core-excited states by using ultraviolet-visible fluorescence spectroscopy and photon-photon delayed coincidence technique. Fluorescence emission yields were measured in the photon energy range of 240-–255 eV for the 3s23p4(1D)5s(2D) → 3s23p4(1D)4p(2F) (393 nm) and 3s23p4(1D)4d(2F) → 3s23p4(1D)4p(2F) (335 nm) transitions...
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Experimental determination of H2 mass stopping powers for low-energy electrons
PublicationWe present experimental mass stopping powers of electrons in gaseous H2 obtained with an electron time- of-flight spectrometer, for the incident electron energy range of 11 to 25 eV. In our procedure, the average energy loss is derived from conversion of the measured electron time-of-flight spectra into equivalent electron energy-loss spectra. Our present results are compared with the only available experimental measurement and...
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Andrzej Okuniewski dr inż.
PeopleEducation 2010-2014: Department of Inorganic Chemistry, Faculty of Chemistry, Gdańsk University of TechnologyPhD in chemical sciences (chemical sciences - chemistry, inorganic chemistry) 2009-2010: Faculty of Chemistry, Gdańsk University of TechnologyMaster of Chemistry (applied chemistry) 2005-2009: Faculty of Chemistry, Gdańsk University of Technologychemical engineer (applied chemistry) 2002-2005: II High School Władysław Pniewski...
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Kod fontannowy z przyrastającą liczbą symboli źródłowych
PublicationKody fontannowe zabezpieczające transmisję przed wymazaniami wyróżnia brak określonej z góry długości i losowy sposób generacji kolejnych pakietów kodowych. W pracy pokazano jak właściwości tych kodów zależą od rozkładu macierzy generującej dla dwóch wariantów dostarczania pakietów do kodera. Szczególnie interesujący jest przypadek, gdy pakiety źródłowe trafiają do kodera stopniowo podczas transmisji. Uzyskane wyniki wskazują na...
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Polypropylene structure alterations after 5 years of natural degradation in a waste landfill
PublicationUp to 25% of plastic waste in Europe is still disposed of in landfills, despite recycling efforts. The plastic waste in the landfill plot may be exposed both to abiotic and biotic degradation processes, although it is thought that most of the plastic materials tend to be resistant to biodegradation or biodeterioration even after a long time. To verify if polypropylene (PP) can undergo the process of short-term biodegradation and...
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Electrochemically assisted deposition of hydroxyapatite on Ti6Al4V substrates covered by CVD diamond films — Coating characterization and first cell biological results
PublicationAlthough titaniumand its alloys are widely used as implant material for orthopedic and dental applications they show only limited corrosion stability and osseointegration in different cases. The aim of the presented research was to develop and characterize a novel surface modification system from a thin diamond base layer and a hydroxyapatite (HAp) top coating deposited on the alloy Ti6Al4V widely used for implants in contact with bone....
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Effect of selective laser treatment on initiation of fatigue crack in the main part of an undercarriage drag strut
PublicationThis paper presents the results of material characterization and a fatigue test conducted for a laser-re-melted drag strut used in an aircraft landing gear. The drag strut was re-melted with a CO2 laser beam. Eight re-melted paths were made in the form of spiral lines along the axis of the drag strut. Next, the drag strut was subjected to variable loads on a testing machine simulating loads occurring when an aircraft lands. The...
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Novel Functionalization of Boron-Doped Diamond by Microwave Pulsed-Plasma Polymerized Allylamine Film
PublicationWe report the novel modification of a hydrogen-terminated polycrystalline boron-doped electrode with a microwave pulsed-plasma polymerized allylamine. Boron-doped diamond (BDD) was coated with a very thin layer of adherent cross-linked, pinhole- and additive-free allylamine plasma polymer (PPAAm) resistant to hydrolysis and delamination and characterized by a high density of positively charged amino groups. The pulsed microwave...
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Structural and electrical properties of Cr-doped SrTiO 3 porous materials
PublicationSeries of single-phase materials with assumed formula SrTi1−xCrxO3 (where x = 0, 1, 4, 6 mol.%) were obtained by sol-gel method. The structure and microstructure of materials were characterised by X-ray diffraction and scanning electron microscopy methods. Moreover, the study of electrical properties and evaluation of chemical stability in CO2/H2O atmosphere was performed by electrochemical impedance spectroscopy and thermogravimery...
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Metal dusting phenomena of 501 AISI furnace tubes in refinery fractional distillation unit
PublicationThe purpose of this investigation was to conduct the failure analysis of 501 AISI furnace tubes places before distillation column in fractional distillation unit. The investigated furnace tubes were planned to work for ten years however after just two years of exploitation <30% of the material left. The observed corrosion process had the intense and complex character. The well-adhered shiny black deposits and deep, round pits were...
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Fabrication and Study of BiNbO4 Ceramics
PublicationAim of the present research was to fabricate and study crystalline structure as well as dielectric properties of BiNbO4 ceramics. In the present study BiNbO4 ceramics was fabricated by solid state reaction from the mixture of simple oxides viz. Bi2O3, and Nb2O5. Stoichiometric mixture of the powders was thermally analyzed so parameters of the thermal treatment were determined. The EDS measurements proved conservation of the chemical...
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Effect of Semiconductor Element Substitution on the Electric Properties of Barium Titanate Ceramics
PublicationThe investigated ceramics were prepared by a solid-state reaction from simple oxides and carbonates with the use of a mixed oxide method (MOM). The morphology of BaTi0.96Si0.04O3 (BTSi04) ceramics was characterised by means of a scanning electron microscopy (SEM). It was found that Si+4 ion substitution supported the grain growth process in BT-based ceramics. The EDS results confirmed the high purity and expected quantitative composition...
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Highly Active TiO2 Microspheres Formation in the Presence of Ethylammonium Nitrate Ionic Liquid
PublicationSpherical microparticles of TiO2 were synthesized by the ionic liquid-assisted solvothermal method at different reaction times (3, 6, 12, and 24 h). The properties of the prepared photocatalysts were investigated by means of UV-VIS diffuse-reflectance spectroscopy (DRS), Brunauer–Emmett–Teller (BET) surface area measurements, scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy...
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Assessment of unusual failure in crankshaft of heavy-duty truck engine
PublicationThe unusual premature failure of a heavy-duty truck engine crankshaft has been the subject of a rigorous study, and this manuscript describes it in detail. The failure was happened to begin with the growth of the crack from the surface defects, in the form of the clusters of non-metallic inclusions, in the lubrication hole zone of the first main journal, which was the stress concentration zone. A series of experiments including...
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Role of size scale of ZnO nanoparticles and microparticles on toxicity toward bacteria and osteoblast cancer cells
PublicationThe specific role of size scale, surface capping, and aspect ratio of zinc oxide (ZnO) particles on toxicity toward prokaryotic and eukaryotic cells was investigated. ZnO nano and microparticles of controlled size and mor- phology were synthesized by wet chemical methods. Cytotoxicity toward mammalian cells was studied using a human osteoblast cancer cell line and antibacterial activity using Gram-negative bacteria (Escherichia...
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Investigation of the Few‐Layer Black Phosphorus Degradation by the Photonic Measurements
PublicationFew-layer black phosphorus (FLBP) is a 2D material that gains worldwide interest for its possible applications, mainly in electronics and optoelec-tronics. However, as FLBP is prone to a degradation process under envi-ronmental conditions, there is a need for a monitoring method allowing investigation of its surface quality. Among many techniques, optoelectronic ones have unique advantages of fast response, non-contact, and non-invasive...
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Disinfection characteristics of an advanced rotational hydrodynamic cavitation reactor in pilot scale
PublicationHydrodynamic cavitation is a promising technique for water disinfection. In the present paper, the disinfection characteristics of an advanced hydrodynamic cavitation reactor (ARHCR) in pilot scale were studied. The effects of various flow rates (1.4–2.6 m3/h) and rotational speeds (2600–4200 rpm) on the removal of Escherichia coli (E. coli) were revealed and analyzed. The variation regularities of the log reduction and reaction...
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Structure and transport properties of triple-conducting BaxSr1−xTi1−yFeyO3−δ oxides
PublicationIn this work, BaxSr1−xTi1−yFeyO3−δ perovskite-based mixed conducting ceramics (for x = 0, 0.2, 0.5 and y = 0.1, 0.8) were synthesized and studied. The structural analysis based on the X-ray diffraction results showed significant changes in the unit cell volume and Fe(Ti)–O distance as a function of Ba content. The morphology of the synthesized samples studied by means of scanning electron microscopy has shown different microstructures...