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The effect of BaF

In this work, platinum nanoparticles (PtNPs) were synthesized by a modified polyol process using TEMPO-oxidized nanocellulose (TOCN) as a stabilizing and co-reducing agent. Different ratios of TOCN nanocellulose to Pt

Benzoxaboroles emerged recently as molecules of high medicinal potential with Kerydin&reg, (Tavaborole) and Eucrisa&reg, (Crisaborole) currently in clinical practice as antifungal and anti-inflammatory drugs, respectively. Over a dozen of 3-amino benzoxaboroles, including Tavaborole&rsquo, s derivatives, have been synthetized and characterized in terms of their activity against Candida albicans as a model pathogenic fungus. The studied compounds broaden considerably the structural diversity of reported benzoxaboroles, enabling determination of the influence of the introduction of a heterocyclic amine, a fluorine substituent as well as the formyl group on antifungal activity of those compounds. The determined zones of the growth inhibition of examined microorganism indicate high diffusion of majority of the studied compounds within the applied media as well as their reasonable activity. The Minimum Inhibitory Concentration (MIC) values show that the introduction of an amine substituent in position &ldquo, 3&rdquo, of the benzoxaborole heterocyclic ring results in a considerable drop in activity in comparison with Tavaborole (AN2690) as well as unsubstituted benzoxaborole (AN2679). In all studied cases the presence of a fluorine substituent at position para to the boron atom results in lower MIC values (higher activity). Interestingly, introduction of a fluorine substituent in the more distant piperazine phenyl ring does not influence MIC values. As determined by X-ray studies, introduction of a formyl group in proximity of the boron atom results in a considerable change of the boronic group geometry. The presence of a formyl group next to the benzoxaborole unit is also detrimental for activity against Candida albicans.

The comprehensive results regarding the physicochemical properties of carbonaceous materials that are obtained from pistachio shells support their usage as solid fuels to supply direct carbon solid oxide fuel cells (DC-SOFCs). The influence of preparation conditions on variations in the chemical composition, morphology of the biochar powders, and degree of graphitization of carbonaceous materials were investigated. Based on structural investigations (X-ray diffraction analysis and Raman spectroscopy), it was observed that disordered carbon particles developed during the application of thermal treatments. The use of X-ray fluorescence enabled a comparative analysis of the chemical composition of the inorganic matter in biocarbon-based samples. Additionally, the gasification of carbonaceous-based samples vs. time at a temperature of 850 °C was investigated in a H2O or CO2 gas atmosphere. The analysis demonstrated the conversion rate of biochar obtained from pistachio shells to H2, CH4 and CO during steam gasification. The electrochemical investigations of the DC-SOFCs that were supplied with biochars obtained from pistachio shells were characterized by satisfactory values for the current and power densities at a temperature range of 700–850 °C. However, a higher power output of the DC-SOFCs was observed when CO2 was introduced to the anode chamber. Therefore, the impact of the Boudouard reaction on the performance of DC-SOFCs was confirmed. The chars that were prepared from pistachio shells were adequate for solid fuels for utilization in DC–SOFCs.

An essential problem in managing CO2 and transforming it into methane as a useful fuel is the quest for adequately efficient and cheap catalysts. Another condition is imposed by the new designs of structured reactors, which require catalysts in the form of the thinnest possible films. The aim of this work was to produce Ni-based thin-film catalysts by the cold plasma deposition method (PECVD) from a volatile metal complex (Ni(CO)4) and to study their structure and catalytic properties in the CO2 methanation process. We tested three basic types of films: as-deposited, calcined in Ar, and calcined in air. The nanostructure and molecular structure of the films were investigated by electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The catalytic activity was evaluated in the methanation process (CO2 + H2), which was performed in a tubular reactor operating in the temperature range of 300–400 °C. The films calcined in air showed the highest activity in this process but behaved unstably. However, their regeneration by recalcination in air restored the initial catalytic activity. An important conclusion emerged from the obtained results, namely that the active phase in the tested films is Ni3+ (most likely in the form of Ni2O3), contrary to the common opinion that this phase is metallic Ni0. In our case, Ni0 quenches the catalytic activity.

The fabrication and photophysical characterization of polymeric fiber preforms, obtained from a polymerization process of poly(methyl methacrylate) (PMMA) doped with terbium(III)-tris-(2,2,6,6-tetramethyl-3,5-heptanedionate) (Tb(tmhd) 3 ) at 1.12–1.13 mmol concentration and co-doped with europium(III)-tris-(2,2,6,6-tetramethyl-3,5-heptanedionate) (Eu(tmhd) 3 ) at different concentrations, is reported. The preforms show a variation in photoluminescent emission due to energy transfer from Tb 3+ to Eu 3+ embedded in PMMA matrix. FTIR and FTR spectroscopy measurements indicate that lanthanide complexes are not chemically bonded to the polymeric matrix, however, the successful interaction between them, enables the formation of a composite with excellent multicolor photoluminescent properties. Moreover, thermal resistance of PMMA doped with the Ln(tmhd) 3 complexes improves (∼100 °C). The best thermal properties were obtained for a 1.12 and 2.62 mmol concentration of Tb 3 and Eu 3+ complex in PMMA respectively.

The effect of BaO content on the glass-forming ability, glass stability and structure of tellurite–phosphate oxide glasses in the 70TeO2–10P2O5–(20-x)ZnO–xBaO (x = 0, 5 and 10 mol%) system has been discussed. From the differential scanning calorimetry, the glass transition (Tg), crystallization (Tc) and the melting (Tm) temperatures were estimated. The decrease in reduced glass transition temperature (Trg) and glass-forming tendency parameter (Kh(Tc1)) with addition and increasing BaO caused a decrease in the glass-forming ability of glasses. It was also found that the thermal stability of these glasses against crystallization decreased with increase in BaO concentration into chemical composition of base glass, i.e., glass without barium oxide. The FTIR spectra were measured to understand the structure of the obtained tellurite–phosphate oxide glasses. The results have shown that phosphorous and tellurium ions were taken part in the formation of the glass network of the studied glasses. The addition of BaO caused significant changes in the FTIR spectra of glasses. More and more TeO3 and TeO3+δ units and PO42− groups (Q1 units) were created when the BaO was added into the chemical composition of the base glass. Increasing barium ions content into the chemical composition of glasses caused depolymerization of the tellurite–phosphate oxide glass network.

Low-melting frits are most often applied in the form of coatings for ceramic building materials, i.e., roof tiles and brick facade. A thin layer of glaze or sintered engobe improves decorative and functional properties of the final product. The roof tiles are fired in the low temperature range (1000–1200 °C). There are expected solutions which will allow obtaining a smooth layer of glaze without deteriorating mechanical and chemical properties. Thus, it is important to find a solution that meets the above requirements. The aim of this study was to analyze the effect of bismuth (III) oxide on the properties of low-melting different commercial frits used as a main component of glaze for ceramic roof tiles. Three commercial frits were modified with the addition of bismuth (III) oxide in the amount of 5 and 10 wt%. In the first stage, the results of the dilatometric and high-temperature microscopy analysis are shown.

The aim of this study was to examine efficacy of different fractions of TEMPO-oxidized cellulose nanocrystals (TOCNs) as a reducing and capping agent of silver nanoparticles (AgNPs). Silver nanoparticles were prepared by thermal treatment of AgNO3 in aqueous suspensions of TOCN fractions. Three different nanocomposite materials based on different fractions of TOCNs and reduced in situ by TOCN silver nanoparticles were obtained. It was demonstrated that three fractions of TOCNs, characterised by varying water-solubility, degree of oxidation and viscosity, bind silver nanoparticles differently. The capping of anionic TOCNs fractions on the surface of nanoparticles was confirmed by zeta potential measurements, and therefore good stability of AgTOCNs nanoparticles was shown. The size and dispersion of AgNPs seems to be affected mainly by the viscosity of a given TOCN fraction. Water-soluble TOCN fractions yielded spherical AgNPs, while water-insoluble fractions contributed to the formation of nanoparticles characterised by diverse morphologies. The application of TEMPO-oxidized cellulose fractions for greener synthesis of silver nanoparticles is discussed. A mechanism including a polylol process is proposed as a possible means of silver cation reduction. The morphology and structural features of the TOCN nanocellulose-silver nanoparticle composites were assessed with the use of spectroscopic and microscopic techniques.

In this work, particular attention was paid to the structural characteristics of the amorphous phase in glass-ceramic glazes from the SiO2 Al2O3 CaO MgO Na2O K2O ZnO system. The study was carried out on model glasses whose chemical composition corresponds to the chemical composition of the vitreous phase of the glazes determined on the basis of electron probe micro-analyzer (EMPA). Structural investigations of the obtained model glasses were carried out using the mid-infrared (MIR) and solid-state magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. The solid-state MAS-NMR study carried out on 27Al and 29Si nuclei showed that all aluminum and silicon ions have tetrahedral coordination and thus form the glass network. The results of the 29Si solid-state MAS-NMR measurements also showed that with the increase of ZnO content in the glass chemical composition, the number of Q3 and Q2 silicon-oxygen units increases at the expense of Q4 (where n is the number of bridging oxygens), thus indicating an increase in the degree of depolymerization of the alumino-silico-oxygen network of studied of glasses. Analysis of the MIR spectra of the obtained glasses confirmed the conclusions from the solid-state MAS-NMR research, i.e. that Zn2+ ions cause depolymerization of the glass network of glazes. The weakening of the network of glasses resulted in lowering of the transformation and dilatometric softenings temperature. The tests carried out on model glasses allow drawing conclusions about the structure and properties of the vitreous phase of real glazes.

The near-infrared emission properties in low-phonon (805 cm−1) gallo-germanate glasses and their glass fibers co-doped with Yb3+/Ho3+ and Yb3+/Tm3+/Ho3+ have been investigated. Emission bands centered at about 2 μm correspond to 3F4 → 3H6 (Tm3+) and/or 5I7 → 5I8 (Ho3+) transitions. The spectral widths of emission lines are relatively large and their values for glass samples co-doped with 0.7Yb2O3/0.15Ho2O3 and 0.5Yb2O3/0.4Tm2O3/0.05Ho2O3 are close to 159 nm and 343 nm, respectively. Gallo-germanate glasses characterized by broadband emission at 2 μm have been used for fabrication of glass fibers. The effects of fibers length on their near-infrared luminescent properties have been also analyzed in details.

The effect of the SrO addition on the microstructure and structure of the glazes from the SiO2–Al2O3–CaO–MgO–K2O system was investigated in this study. The results were obtained by testing the ability of the frits crystallization, the stability of the crystallizing phases during the single-step fast-firing cycle depending on their chemical composition and the effect of addition of strontium oxide. Differential scanning calorimetry (DSC) curves showed that all glazes crystallized, and diopside and anorthite were mainly identified as dominant phases in the obtained glazes, while the size and amount of each depended on the amount of SrO introduced. The thermal characteristic of the frits was carried out using DSC, and crystalline phases were determined by X-ray diffractometry. The glaze microstructure was investigated by scanning electron microscopy and transmission electron microscopy. Additional information on the microstructure of frits was derived from spectroscopic studies in the mid-infrared range.

The purpose of the following work was to provide a performance evaluation of protective coatings based on silicon oxycarbide (Si-O-C) glasses (also known as “black glasses”), which act as a corrosion barrier on the TiAl alloy. A novel coating material was prepared by the sol-gel method with ladder-like polysilsesquioxanes as the precursors of black glasses. Alloy samples, which underwent a thoroughly defined surface preparation (grinding/polishing and degreasing), were dip-coated with synthesized sol. A series of structural studies (XRD, MIR, and EDS) was carried out to confirm whether black glass layers were obtained as a result of appropriate heat treatment consisting of drying and subsequent pyrolysis at 800 °C in an inert argon atmosphere. After an evaluation of the microstructure of coatings (SEM and Confocal microscopy), thermogravimetric analyses (TGA) were performed in laboratory air atmosphere at 800 °C for 100 h. The mass gain of coated samples was below 0.2 [mg/cm2] after 100 h, nearly one order of magnitude lower than that for the uncoated sample. After that, structural (XRD and EDS) and microstructural (SEM and Confocal microscopy) studies of surface and cross-section of samples were conducted. A comparison of structure and microstructure of oxidized, coated, and as-received specimens revealed a promising capability of black glass coatings to act as a protective layer for high-temperature corrosion.

Fluoroindate glasses co-doped with Pr3+/Er3+ ions were synthesized and their near-infrared luminescence properties have been examined under selective excitation wavelengths. For the Pr3+/Er3+ co-doped glass samples several radiative and nonradiative relaxation channels and their mechanisms are proposed under direct excitation of Pr3+ and/or Er3+. The energy transfer processes between Pr3+ and Er3+ ions in fluoroindate glasses were identified. In particular, broadband near-infrared luminescence (FWHM = 278 nm) associated to the 1G4 → 3H5 (Pr3+), 1D2 → 1G4 (Pr3+) and 4I13/2 → 4I15/2 (Er3+) transitions of rare earth ions in fluoroindate glass is successfully observed under direct excitation at 483 nm. Near-infrared luminescence spectra and their decays for glass samples co-doped with Pr3+/Er3+ are compared to the experimental results obtained for fluoroindate glasses singly doped with rare earth ions.

Glass-ceramic is semi-novel material with many applications, but it is still problematic in obtaining fibers. This paper aims to develop a new glass-ceramic material that is a compromise between crystallization, thermal stability, and optical properties required for optical fiber technology. This compromise is made possible by an alternative method with a controlled crystallization process and a suitable choice of the chemical composition of the core material. In this way, the annealing process is eliminated, and the core material adopts a glass-ceramic character with high transparency directly in the drawing process. In the experiment, low phonon antimony-germanate-silicate glass (SGS) doped with Eu3+ ions and different concentrations of P2O5 were fabricated. The glass material crystallized during the cooling process under conditions similar to the drawing processes’. Thermal stability (DSC), X-ray photo analysis (XRD), and spectroscopic were measured. Eu3+ ions were used as spectral probes to determine the effect of P2O5 on the asymmetry ratio for the selected transitions (5D0 → 7F1 and 5D0 → 7F2). From the measurements, it was observed that the material produced exhibited amorphous or glass-ceramic properties, strongly dependent on the nucleator concentration. In addition, the conducted study confirmed that europium ions co-form the EuPO4 structure during the cooling process from 730 °C to room temperature. Moreover, the asymmetry ratio was changed from over 4 to under 1. The result obtained confirms that the developed material has properties typical of transparent glass-ceramic while maintaining high thermal stability, which will enable the fabrication of fibers with the glass-ceramic core.

Fluoroindate glasses co-doped with Pr3+/Er3+ ions were synthesized and their near-infrared luminescence properties have been examined under selective excitation wavelengths. For the Pr3+/Er3+ co-doped glass samples several radiative and nonradiative relaxation channels and their mechanisms are proposed under direct excitation of Pr3+ and/or Er3+. The energy transfer processes between Pr3+ and Er3+ ions in fluoroindate glasses were identified. In particular, broadband near-infrared luminescence (FWHM = 278 nm) associated to the 1G4 → 3H5 (Pr3+), 1D2 → 1G4 (Pr3+) and 4I13/2 → 4I15/2 (Er3+) transitions of rare earth ions in fluoroindate glass is successfully observed under direct excitation at 483 nm. Near-infrared luminescence spectra and their decays for glass samples co-doped with Pr3+/Er3+ are compared to the experimental results obtained for fluoroindate glasses singly doped with rare earth ions.

In the article, the effect of samarium ions doping on the spectroscopic and biological properties of 45S5 Bioglass® was presented. The luminescence spectra of doped glasses have been analyzed in the visible range under 405 nm laser excitation. The in vitro method for testing the apatite-forming ability of bioactive glasses was used. Crushed to 100μm fractions bioactive glasses were immersed in Simulated Body Fluid (SBF) prepared by the Kokubo method. The material was incubated at 37°C for 3 days and then the measurements of ions (Ca, Na, Si) release in SBF were carried out. The bioactivity test indicated that Sm3+ ions affect not only on the luminescent properties of the bioactive glasses but also their capability of creating the hydroxycarbonate-apatite (HCA) layer.

Glass and ceramic materials doped with rare earth (RE) ions have gained wide interest in photonics as active materials for lasers, optical amplifiers, and luminescent sensors. The emission properties of RE-doped glasses depend on their chemical composition, but they can also be tailored by modifying the surrounding active ions. Typically, this is achieved through heat treatment (including continuous-wave and pulsed lasers) after establishing the ordering mechanisms in the particular glass&ndash, RE system. Within the known systems, silicate glasses predominate, while much less work relates to materials with lower energy phonons, which allow more efficient radiation sources to be constructed for photonic applications. In the present work, the luminescent and structural properties of germanate glasses modified with phosphate oxide doped with Eu3+ ions were investigated. Europium dopant was used as a &ldquo, spectroscopic probe&rdquo, in order to analyze the luminescence spectra, which characterizes the changes in the local site symmetries of Eu3+ ions. Based on the spectroscopic results, a strong influence of P2O5 content was observed on the excitation and luminescence spectra. The luminescence study of the most intense 5D0&rarr, 7F2 (electric dipole) transition revealed that the increase in the P2O5 content leads to the linewidth reduction (from 15 nm to 10 nm) and the blue shift (~2 nm) of the emission peak. According to the crystal field theory, the introduction of P2O5 into the glass structure changes the splitting number of sublevels of the 5D0&rarr, 7F1 (magnetic dipole) transition, confirming the higher polymerization of fabricated glass. The slightly different local environment of Eu3+ centers the results in a number of sites and causes inhomogeneous broadening of spectral lines. It was found that the local asymmetry ratio estimated by the relation of (5D0&rarr, 7F2)/(5D0&rarr, 7F1) transitions also confirms greater changes in local symmetry around Eu3+ ions. Our results indicate that modification of germanate glass by P2O5 allows control of their structural properties in order to functionalize the emissions for application as luminescent light sources and sensors.

An investigation of the crystallization kinetics of 45S5 Bioglass® using differential scanning calorimetry is presented in this paper. Thermal analysis was performed using the Friedman method. The activation energy and the Avrami index were calculated. The glass samples were subjected to additional controlled heat treatment at 620 °C in order to obtain bioactive glass-ceramics with enhanced mechanical properties. X-ray powder diffraction (XRD) measurements indicated the formation of the glass-ceramic structures of three cyclosilicates: Na4Ca4(Si6O18) or Na6Ca3(Si6O18) or Na16Ca4(Si12O36). Based on middle infrared region (MIR) results, it can be concluded that the crystalline phase present in the tested materials was Na6Ca3(Si6O18) (combeite). Material was doped with Eu3+ ions, which act as a spectroscopic probe for monitoring the structural changes in the glass matrix. The decreasing value of the fluorescence intensity radio parameter indicated symmetry around the europium ions and, thus, the arrangement of the glass structure. The bioactive properties of the examined glass-ceramics were also determined. The bioactive glass fibers doped with Eu3+ were manufactured using two different methods. Its structural and luminescent properties were examined.

Raw glazes in the SiO2 Al2O3 CaO MgO Na2O K2O ZnO system with ZnO additions (0, 5, 10, 15 and 20 wt%) were synthesized and thermally treated at 1230 °C. Diopside (MgCaSi2O6), β-quartz (the low-temperature form), gahnite (ZnAl2O4) and α-willemite (Zn2SiO4) were the main crystalline phases identified by X-ray investigations in glazes. An increase of the ZnO content from 10 to 20 wt% into the chemical composition of glazes trigged crystallization of the macroscopically visible α-willemite (Zn2SiO4) crystals. Microstructure and structure of the glazes were determined by SEM-EDS, FTIR and 29Si and 27Al MAS NMR spectroscopy. Analysis of MAS NMR spectra showed that silicon (Si4+) and aluminum (Al3+) ions occurred only in tetrahedral coordination in a glassy matrix of all resulting glazes (glass-network ions). The zinc ions (Zn2+) depolymerized the glassy matrix of glazes (network-modifying ions).

Lead phosphate based glasses doubly doped with Tb3+ and Eu3+ ions were prepared and next studied using different spectroscopic techniques. Structural and optical properties of Tb3+ and Eu3+ ions have been investigated in lead phosphate based systems, in which PbO:P2O5 molar ratio were changed from 1:5 to 5:1 in glass composition. The fourier transform infrared (FT-IR) spectroscopy was used to verify local structure of glass-network. The FT-IR spectra clearly indicate that different structural phosphate groups are present in PbO-P2O5 based glasses. Moreover, the areas of the FT-IR bands strongly depend on the relative ratio of PbO and P2O5 components. The luminescence spectra for Eu3+ and Tb3+ ions in PbO-P2O5 glasses were registered. Several emission bands associated to characteristic transitions of trivalent europium and terbium are observed under direct excitation of Tb3+ ions. It indicates that the energy transfer process from Tb3+ to Eu3+ in lead phosphate glasses occurs. Spectroscopic parameters like 5D0 (Eu3+) and 5D4 (Tb3+) luminescence lifetimes were determined. Dependence of spectroscopic parameters on the increase of PbO:P2O5 molar ratio from 1:5 to 5:1 in glass composition was established.

In this study structural and nanomechanical properties of polytetrafluoroethylene (PTFE) used as a gasket in the nuclear reactor have been deeply investigated. In order to reveal structural changes caused by long-term pressure, temperature and irradiation (possibly neutron and gamma), methods such as SEM, X-ray diffraction and Raman Spectroscopy have been used. Nanomechanical properties such as Young Modulus and hardness were investigated by means of the nanoindentation technique. Presented study confirmed the influence of working (radiative) environment on the functional properties of PTFE. The results of Raman spectroscopy and X-ray diffraction techniques revealed shift of the major band positions and band intensities increase. Moreover, changes of hardness and Young Modulus values of the irradiated material with respect to the virgin specimen have been recorded. This phenomenon can be attributed to the modifications in crystallinity of the material. Presented work suggest that morphology of the irradiated material altered from well-ordered parallel fibers to more dense and thicker ones.

This paper presents the results of research on the luminescent properties of antimony-borate glass rods doped with europium and silver ions. The reduction of silver ions to the form of nanoparticles was carried out and the occurrence of localized plasmon resonance was demonstrated, which caused changes in the Eu3+ luminescence signal at a wavelength of 613 nm. The effect of the concentration of silver ions dopant at a constant content of europium ions on the luminescence and absorption characteristics of the produced samples was investigated. In the examined doping range, no large dependencies of spectral changes as a function of the concentration of silver ions were found. A clear quenching of the luminescence was observed due to the heating time of the doped glass matrices for the energy transition (5D0 → 7F2). Full Text: PDF ReferencesS. Kuzman, J. Perisa, V. Dordevic, I. Zekovic, I. Vukoje, Z. Antic and M. D. Dramicanin, "Surface Plasmon Enhancement of Eu3+ Emission Intensity in LaPO4/Ag Nanoparticles", Materials 13, 3071 (2020). CrossRef V.P. Prakashan, M.S. Sajna, G. Gejo, M.S. Sanu, A.C. Saritha, P.R. Biju, J. Cyriac and N.V. Unnikrishan, "Surface Plasmon Assisted Luminescence Enhancement of Ag NP/NWs-Doped SiO2-TiO2-ZrO2:Eu3+ Ternary System", Plasmonics 14, 673 (2019). CrossRef O. Malta, P. Santa-Cruz, G. Sa and F. Auzel, "Fluorescence enhancement induced by the presence of small silver particles in Eu3+ doped materials", J. Lumin., 33, 261 (1985). CrossRef O. Malta, P. Santa-Cruz, G. Sa and F. Auzel, "Time evolution of the decay of the 5Do level of Eu3+ in glass materials doped with small silver particles", Chem. Phys. Lett, 116, 396 (1985). CrossRef J. Zmojda, M. Kochanowicz, P. Miluski et al., "The influence of Ag content and annealing time on structural and optical properties of SGS antimony-germanate glass doped with Er3+ ions", Journal of Molecular Structure 1160, 428 (2018). CrossRef Ki Young Kim, Plasmonics: Principles and Applications (Croatia, InTechOpen 2012) CrossRef M.R. Dousti, M.R. Sahar, S.K. Ghoshal et al., "Up-conversion enhancement in Er3 +-Ag co-doped zinc tellurite glass: Effect of heat treatment", Journal of Non-Crystalline Solids 358, 2939 (2012). CrossRef I. Soltani, S. Hraiech, K. Horchani-Naifer et al., "Effect of silver nanoparticles on spectroscopic properties of Er3+ doped phosphate glass", Optical Materials 46, 454 (2015). CrossRef R. Schneider, E.A. de Campos, J.B.S. Mendes, J.F. Felix, P.A. Santa-Cruz, "Lead–germanate glasses: an easy growth process for silver nanoparticles and their promising applications in photonics and catalysis", RSC Advances 7 (66), 41479 (2017). CrossRef

The aim of the presented study was to evaluate the potential of ceramic coating to reduce titanium susceptibility to corrosion. Ceramic coatings composed of zirconia and zirconia-silica were investigated. To examine the surface morphology of the samples, the investigation under Scanning Electron Microscope and Confocal Microscope was performed and the coatings with the lowest amount of cracks were chosen for further evaluation, involving wettability and Surface Free Energy studies. Furthermore, measurement of the corrosion resistance of the obtained samples was done via polarization technique, ran in a 3-electrode set-up. The impact on cells' morphology, cells' viability and cytotoxicity were investigated in vitro using Normal Human Osteoblasts. Finally, the stability of the obtained coatings was studied by immersing and incubating the samples in different solutions of artificial saliva (with a varying value of pH) and investigating the coatings' susceptibility to cracking by SEM and confocal microscopy. Both types of coating have been proven to decrease the susceptibility to corrosion of titanium materials. Single zirconia-silica layer present better corrosion protection than single zirconia layer. Biological research carried out as part of our experiment revealed that the zirconia-silica layer does not compromise titanium biocompatibility. In summarize single zirconia-silica layer protect titanium implant from corrosion processes while the lack of the negative influence on osteoblast multiplication.

In this work, the structure and thermal properties of aluminosilicate fritted glazes in SiO2–Al2O3–CaO–MgO–Na2O–K2O–ZnO system with (4.0 mol%) and without addition of ZnO were examined by GIXRD, FTIR, MAS-NMR and thermal methods (DTA, DIL). It has been found that the all experimental glazes are amorphous material (transparent glazes). On the base of spectroscopic investigations, it was found that zinc ions exist in the network glazes in the octahedral coordination—Zn2+ ions play a network modifier role in structure of glazes. An analysis of the data obtained from thermal tests showed that addition of ZnO into chemical composition results in decrease in glass transition temperature value (Tg) for all glazes (DTA, DIL). The coefficient of thermal expansion (α) is decreased as the whole measurement range for one series of fritted glazes.

Thermal properties of raw aluminosilicate ceramic glazes in the multicomponent system of SiO2–Al2O3–CaO–K2O–Na2O–ZnO modified by ZnO addition were studied by differential thermal analysis (DTA), dilatometry (DIL), hot-stage microscopy (HSM), X-ray diffraction and fourier transform infrared spectroscopy (FTIR). Using the method of differential thermal analysis, the ways in which zinc oxides affect the temperature of transition (T g), crystallisation (T c) were determined. An analysis of the DTA data obtained during thermal tests showed that an increase in ZnO content results in decreasing the T g value. Also, the influence of ZnO on characteristic temperatures and viscosity of glazes was checked. The introduction of zinc oxide (ZnO) into the glaze composition contributes to the decrease in viscosity of such glazes. An increasing ZnO content in the glazes also causes the reduction in softening (T s), half-sphere (T half-sphere) and fusion (T fusion) temperatures. The mid-infrared spectroscopy showed that the thermal properties of glazes in SiO2–Al2O3–CaO–K2O–Na2O–ZnO system modified by addition of ZnO can be associated with the depolymerising influence of zinc ions on the structure of the tested glazes.

This article is an attempt to analyze parental authority in the context of selected theories of education. Considerations have been made regarding the definition of authority, its types, parental authority and its importance in the process of upbringing. Efforts were also made to answer the question of what is the share of authority in the process of upbringing in selected theories of education. To this end, reference was made to anti-pedagogics, Carl Rogers's non-direct pedagogy, Thomas Gordon's non-authoritarian pedagogy and Janusz Tarnowski personal-existential pedagogy.

Antimony-based glasses with different germanium oxide content doped with Sm 3+ ions have been developed. On the basis of decomposition of absorption bands (FTIR) in the mid infrared region, was determined that antimony and germanium ions are the glass-forming ions, setting up the lattice of fabricated glasses. The effect of GeO 2 /Sb 2 O 3 ratio in fabricated glass doped with samarium ions on thermal, structural and luminescent properties was also investigated. Characteristic bright reddish-orange luminescence from the 4 G 5/2 state to the lower lying levels 6 H J with J = 5/2, 7/2, 9/2 and 11/2 with maximum intensity at the wavelength of 603 nm originating from 4 G 5/2 → 6 H 7/2 transition was observed. The asymmetry nature of molecular structure around samarium ion have been determined from intensity ratio between 4 G 5/2 → 6 H 9/2 (ED) and 4 G 5/2 → 6 H 5/2 (MD) transitions. An introduction of GeO 2 to the antimony glass results in the increasing of 4 G 5/2 lifetime and decreasing of the orange-to-red intensity ratio, which is are related to reduction of non-briding oxygens.

This paper presents the results of research on aluminum silicate sanitary glazes in the SiO2-Al2O3-CaO-Na2O system with different SiO2/Al2O3 molar ratio. XRD, SEM-EDS and FITR measurement indicated that SiO2/Al2O3 molar ratio has a significant impact on the phase composition of the obtained glazes. Glass-ceramic glazes were obtained that consisted of both the glass phase and pseudowollastonite (Ca3[SiO3]3) or anorthite (Ca[Al2Si2O8]) crystals. Subsequently, the influence of phase composition on surface quality (roughness) was examined for the obtained samples. On the basis of the conducted examination of glaze surface roughness was observed that glazes of extreme SiO2/Al2O3 molar ratio are characterized with greatest surface roughness when compared to other glazes.

This paper is focused on the relationship between the phase composition and opaque of glass-ceramic glazes from the SiO2–Al2O3–MgO–K2O–Na2O system by variable molar ratio of SiO2/Al2O3. The phase composition obtained from the glazes was determined using X-ray diffraction (XRD) and the glaze morphology were examined by scanning electron microscopy with elemental composition analyser in the microregions (SEM-EDS). Additional information on the microstructure was provided by spectroscopic investigation in the mid- and far-infrared regions as well as by Raman spectroscopy. In order to correlate the phase composition of the optical properties of experimental glazes were measured by their opacity. The increase of molar ratio of SiO2/Al2O3 in experimental glazes caused to decrease of opacity glazes. At the highest content of Al2O3 was obtained transparent glaze.

The basic factor limiting the use of glasses is their unsatisfactory mechanical strength. The improvement of the mechanical strength of glasses is usually obtained by applying their respective thin surface layers. The object of the research was glass coated with zirconium oxide. For the application of zirconium oxide layer, dip-coating method was used. The resulting materials were subjected to detailed examination of the microstructure (SEM), and mechanical tests (Vickers hardness and modulus of elasticity). In order to evaluate the optical characteristics, the tests were performed by UV/VIS. The thickness of the overlying layers were determined using the method of ellipsometry. The study showed that the obtained sol-gel layer of zirconium oxide (IV) on glasses influence the improvement of the mechanical properties. It has been shown that the applied layers have high adhesion to the substrate.

Far-reaching technological progress, manufacturing, and rapidly advancing globalization dictate new conditions for the development and changes in the construction industry. Valorization of by-products and the use of secondary materials in the production of building materials have attracted a lot of attention. Silicate materials were assessed on the basis of their compressive property. An orthogonal compositional plan type 3k (with k = 2), that is, a full two-factor experiment was applied in order to carry out the compressive strength and bulk density tests. Glass sand was added to the silicate mass as a modification. The results show that the compressive strength was higher than that of traditional bricks. Scanning electron microscopy coupled with energy dispersive spectrometry SEM/EDS was used to study the microstructure, whereas the XRD analysis was applied to examine the structures. Laboratory tests were performed on samples with dimensions of 50 × 50 × 50 mm. The results show the bulk density increase to the value of 1.75 kg/dm3, which increases the acoustic performance of the new products. The results of the modifications also indicate changes in the structure of the new bricks. The reference sample contained α-quartz, zeolite, tobermorite 9A, and calcium aluminum silicate (Ca2Al4Si12O32), whereas the samples modified with glass sand, the presence of phases such as α-cristobalite, natrolite, tobermorite 11A, gyrolite, and analcite was recorded.

Currently, there is a growing interest in the development of multi-colored materials based on the combination of two or more systems (organic or inorganic) as a strategy to take advantage of their combined physical or chemical properties. These multi-colored materials have found potential applications as sensors, amplifiers, and optical fibers. In this work, the physical characteristics of poly(methyl methacrylate) (PMMA) doped with Terbium(III)-tris-(2,2,6,6-tetramethyl-3,5-heptanedionate) (Tb(tmhd)

The main objective of this work was to determine the tightness and wet corrosion resistance of SiAlOC glasses in the form of coatings on a steel substrate. The coatings were optimized in terms of the formation process, along with their resulting structure and microstructure. The coating material was obtained using sol-gel-synthesized, Al-doped, ladder-like polysilsesquioxanes as glasses' precursors. The layers were deposited by means of the dip-coating technique, for which the influence of both surface preparation (grinding/polishing) and withdrawal speed (5, 15, and 30 cm/min) was investigated. After the deposition, a two-stage thermal treatment (curing −70 °C/air and pyrolysis −800 °C/Ar) was applied. A series of structural (XRD, XPS, Raman) studies confirmed the formation of SiAlOC glass coatings, with a noticeable presence of an additional inner layer, most probably of MnCr2O4 spinel. Furthermore, the direct correlation between the increasing content of aluminum and the decreasing amount of carbon inward the coating can be suggested. Additionally, spectroscopic studies revealed the ongoing amorphization process of the free carbon phase. The result was that more crystalline species were present at the surface of the coating and the amorphous phases were near the inner Mn Cr spinel layer. Moreover, a set of microstructural (SEM, EDS, Confocal) studies was performed to evaluate the influence of the investigated deposition parameters on the coatings’ compactness, homogeneity, and thickness. The coating with the best characteristics obtained on the ground substrate when using the lowest withdrawal speed was chosen for the final examination of the tightness via electrochemical corrosion studies in a wet environment of chloride ions. The wet corrosion resistance was nearly 60 times higher for the coated specimen in comparison with the bare steel substrate. Additionally, an uncoated specimen after the same thermal treatment was investigated with the use of the same electrochemical studies. It exhibited significantly higher resistance to the corrosion in the wet environment than the rest of the samples due to the pre-formation of a mixed scale containing highly resistant Cr2O3.

The article presents the results of research aimed at examining the type of swelling material introduced into moulding or core sand to improve their knock-out properties. Tests on Slovak perlite ore (three grain sizes), Hungarian perlite ore and ground vermiculite (South Africa) were carried out. For this purpose, thermal and structural analyses (FTIR—Fourier Transform Infrared Spectroscopy), a chemical composition test (XRF-X-Ray Fluorescence), phase analysis (XRD—X-Ray Diffraction), and scanning electron microscopy (SEM—Scanning Electron Microscope) as well as final strength tests of moulding sands with the addition of perlite ore and vermiculite were carried out. The results of thermal studies were related to IR (Infrared Spectroscopy) spectra and XRD diffractograms. It has been shown that the water content in the pearlite ore is almost three times lower than in vermiculite, but the process of its removal is different. Moreover, the chemical composition of the perlite ore, in particular the alkali content and its grain size, may influence its structure. The phenomena of expansion (perlite) and peeling (vermiculite) have a positive effect on the reduction of the final sand strength and eliminate technological inconveniences (poor knocking out) that significantly limit the wide use of moulding sands with inorganic binders.

This paper uses mathematical methods as the basic tool at the stage of experiment planning. The importance of research programming applications was shown using the theory of experiments and the STATISTICA software. The method of experiment planning used in the case of studying the properties of a mixture, depending on its composition, features considerable complexity. The aim of the statistical analysis was to determine the influence of variable chemical composition of waste materials on selected properties of glass-ceramic materials. A statistical approach to multicomponent systems, such as ceramic sets, enables the selection of appropriate amounts of raw materials through the application of ‘a plan for mixtures’. To utilize the raw waste materials, e.g., slags from a solid waste incinerator, fly or bottom ashes, in the modeling of new materials, a mathematical relationship was developed, which enables estimating, based on the waste chemical composition, selected technological and practical properties of the glass so as to obtain a material featuring the required technological–practical parameters. For the obtained glasses, a comparative analysis of the experimentally and computationally determined properties was carried out: transformation temperature, liquidus temperature, density, and thermal expansion coefficient. The obtained high theoretical approximation (at the level of determination correlation coefficient R2 &gt, 0.8) confirms the suitability of the polynomial model for mixtures for applications in the design of new glass-ceramic products.

The effects of Sm3+ content on the optical properties and bioactivity of 13-93 bioactive glass were presented. Sm3+ doped glass fibers drawn from bioactive glass were analyzed in simulated body fluid (SBF) for the determination of ion release. Optical analysis of the Sm3+ ions in bioactive glass fibers was used for degradation monitoring. While the fibers were immersed in SBF solution, changes in their luminescence spectra under 405 nm laser excitation were measured continuously for 48 h. The morphology of the fibers after the immersion process was determined by SEM/EDS. It was shown that the proposed approach to the analysis of changes in Sm3+ ion luminescence is a sensitive method for the monitoring of degradation processes and the formation of hydroxycarbonate-apatite (HCA) layers on glass fiber surfaces. SEM/EDS measurements showed a significant deterioration on the surface of the fibers and the formation of HCA on 13-93_02Sm bioactive glass. The optical analysis of the time constant indicated that bioactive glass fibers doped with 2 %mol Sm3+ degrade at a rate almost five times slower than 13-93_02Sm.

The subject of the study was to determine the effect of erbium ions (Er3 +) on the structure of tellurite glasses. For this purpose, the positron annihilation lifetime and Raman spectroscopy were used. Changes in positron lifetime parameters and the corresponding intensities have been linked to the geometry and the number of free spaces, the pores of which vary from several angstroms to several dozen nanometers under the influence of erbium (Er3+) doped. Experimental spectra of positron lifetime have two constituent lifetimes of positrons − τ1 and τ2. The interpretation of lifetime components was based on the two-state trappingmodel. The application of Raman spectroscopy allowed to assess that the introduction of erbium ions into the tested phosphate tellurite glasses leads to depolymerization of the tellurium subnet.

This paper is focused on glass–ceramic glazes from the SiO 2 –Al 2 O 3 –CaO–MgO–K 2 O–Na 2 O system with ZnO additions (2.5, 5, 10, 15, 15, 20 and 25 wt%). The compositions were designed based on constant molar ratio of SiO 2 /Al 2 O 3 . In the resulting glazes diopside (CaMg[Si 2 O 6 ]), willemite (Zn 2 SiO 4 ) and vitreous phase were identified by X-ray diffraction. Morphological and structural date of these glazes were supplementary determined by EPMA, FTIR and Raman Spectroscopy. DSC analysis was carried out to characterize thermal properties of the materials.