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New anodes consisting of zirconium-doped PbO2 coating, growth on titanium dioxide interlayer, were deposited on titanium substrates using spin coating method and have been tested for the removal of ampicillin, a β-lactam antibiotic, from water. Morphological, structural, and electrochemical properties of the prepared coatings were characterized by scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), and electrochemical impendence spectroscopy (EIS). Results showed that the incorporation of zirconium dopant had a noticeable modification in the morphology of anodes. An increase in the surface roughness and the specific active area were observed with Ti/TiO2/PbO2- 10% Zr electrode compared to other anodes. The electrochemical measurements indicated that the anode doped with 10% Zr showed a more protective coating performance than the undoped and 20% Zr-doped PbO2 electrodes. The experiments on ampicillin degradation revealed that doped lead dioxide anodes have excellent electrocatalytic activity. The major byproduct generated during anodic oxidation treatment has been identified as ampicilloic acid by liquid chromatography-mass spectroscopy (LC–MS) analysis. Results demonstrated that Ti/TiO2/PbO2- 10% Zr anode presents the best removal rate of ampicillin with a minimum intermediate amount, which leads to conclude that 10% is the optimum percentage of zirconium dopant for antibiotic wastewater treatment. [ABSTRACT FROM AUTHOR]

A method of 90Sr determination in natural waters was tested in this study. The method included the steps of strontium preconcentration by a carbonate-containing zirconium hydroxide (Termoxid-3 K), strontium stripping with 1 M HCl and preparation of a counting source, followed by its measurement using a low background alpha/beta radiometer UMF-2000. Using the described method, we have determined activity concentrations of 90Sr in 16 samples of natural water collected at the territories of Sverdlovsk region and Chelyabinsk region (Middle Urals, Russia) as well as 8 samples from observing wells at a radioactive waste storage facility and 3 samples from observing wells at a point of radioactive waste final disposal. The dependence of strontium chemical yield in the method on calcium concentration and water hardness was determined. It was shown that strontium chemical yield was constant (81 ± 2%) for natural waters with a hardness less than 5.2 mmol/L and calcium concentration less than 76 mg/L; thus, a control of strontium chemical yield is not necessary for such water samples. A decrease of strontium chemical yield to 66.5 ± 1.5% was observed at higher calcium concentrations up to 178 mg/L. The method provided a minimum detectable activity of 90Sr as low as 0.02 Bq/L. [ABSTRACT FROM AUTHOR]

A radiochemical procedure has been developed for the quantification of uranium and thorium isotopes in NORM samples from the ceramic industry, such as zirconium sands, zirconium flours, micronized zircon, pigments and personal aerosol filters. The method is based on a fusion pretreatment with borate salts, a separation with anion exchange resins and alpha-particle spectrometry measurement. This method is an alternative to gamma spectrometry when the amount of sample is extremely small (2–10 mg) as in the case of aerosol filters, or there is no secular equilibrium in the 238U and 232Th chains, as in the ceramic pigments. The method has been validated with different ceramic materials and the comparison of the results with gamma measurements. Its reproducibility was also checked with different sample masses. [ABSTRACT FROM AUTHOR]

Removing contaminated Arsenazo III dye from contaminated effluent is a challenge and of great interest due to its hazard and environmental impact. Therefore, the biggest challenge was producing highly efficient, easy to recycle, and economically inexpensive adsorbent materials for the contaminated dye. Three chemically stable zirconium nanocomposites with unique properties were synthesized by gel-precipitation technology. The composition, chemical, and physical properties of zirconium molybdate, tungstate, and silicate nanocomposites have been extensively proven using many different and appropriate devices such as XRD, SEM–EDX, TEM, FT-IR, BET, DLS, TGA-DTA, and zeta potential. By utilizing the most effective adsorption techniques, Azo-dye was successfully bound to ZrMo-NPs, ZrW-NPs, and ZrSi-NPs composites. The uptake capacities for these composites were measured at 0.29, 0.79, and 1.61 mmol.g−1, respectively. The sorption parameters were optimized as follows: a feed solution pH of 3 for ZrMo-NPs, a pH of 2.3 for ZrW-NPs, and a pH of 2.3 for ZrSi-NPs. The stirring time was set at 30 min, the metal ion concentration was 1.64 mmol L−1, and the sorbent dose was 7.5 mg. The adsorption results agreed well with the Langmuir isotherm and the pseudo-second-order reaction models and demonstrated the endothermic nature and kinetic improvement by increasing temperatures. The three nanocomposites effectively eliminated tainted dye from lab wastewater, offering promise for their potential applications in the future. [ABSTRACT FROM AUTHOR]

Zirconium terephthalate UiO-66 has aroused great interest in catalysis since it exhibits significant flexibility and compatibility for accommodating a high number of defects as well as exceptional thermal and chemical stability. Until now, many works have focused on the modulations of the Zr6-oxo clusters in UiO-66 in terms of diverse synthesis, advanced characterizations, and their catalytic applications. To achieve high catalytic efficiency, it is still highly desired for rationally constructing and modulating the Zr6-oxo clusters with exposed catalytic sites and diverse microenvironments for advanced catalysis. In this review, we provide a comprehensive summary of recent progress on the synthesis of defective UiO-66, qualitative and quantitative characterizations, as well as a logical overview of heterogeneous catalytic applications over the past few years. Finally, the outlooks for the research paradigm of defective UiO-66 are discussed. [ABSTRACT FROM AUTHOR]

Measurement of the thermophysical properties of liquid metals is a highly challenging task due to numerous problems encountered above the fusion point. Properties such as density and surface tension have been widely investigated, while few studies address thermal diffusivity. In this paper we describe an original methodology for estimating the thermal diffusivity of metals in the liquid state. The proposed experimental setup is based on the traditional flash method. Its design ensures that samples of liquid metal are self-contained, preventing contamination and allowing measurements at high temperature. Results for both solid and liquid iron and 304 stainless steel are presented and compared to data suggested by the literature for validation. Then, for the first time, thermal diffusivity measurement of liquid zirconium is performed giving results up to 2450 K. Giving the high sensitivity of the results to the thickness variation we propose a numerical approach to deal with this issue. [ABSTRACT FROM AUTHOR]

The results of the studies of the corrosion resistance of Al–Mg alloys with different contents of magnesium and different ratios of scandium and zirconium (Sc : Zr) have been presented. The alloys have been obtained using induction casting. The effect of the annealing temperature on the microhardness and specific electrical resistivity of cast Al–Mg–Sc–Zr alloys has been studied. Electrochemical corrosion tests were performed in an environment simulating intergranular corrosion in aluminum alloys. It has been shown that an increase in the content of magnesium results in an increase in the corrosion current, and a decrease in the content of scandium (under the condition of Sc + Zr = const) results in a decrease in the rate of intergranular corrosion. It has been established that the dependence of the corrosion current density on the annealing temperature of Al–Mg–Sc–Zr alloys with an increased Sc : Zr ratio exhibits a non-monotonic pattern with a maximum. [ABSTRACT FROM AUTHOR]

The method of classical molecular dynamics with application of moment tensor potential of interatomic interaction were used to study diffusion properties of pure bcc β-Zr in the temperature range 1800–2100 K. The used potential was pre-trained on the data of ab initio calculations and verified by comparing the calculation results with the available experimental and theoretical data. The constructed potential reproduces the temperature phase transition from hcp α-Zr to bcc β-Zr, the experimental values of the thermal expansion coefficient and the diffusion coefficient, as well as the ab initio calculated equations of state of both phases at low temperatures. The dependence of the self-diffusion coefficient in zirconium on the strain in the range from –3 to 3% is obtained. It is shown that melting of the distorted structure can occur at a temperature below the melting temperature of the undeformed crystal. [ABSTRACT FROM AUTHOR]

A crystallographic theory of the polymorphic bcc → hcp transition in a zirconium single crystal has been formulated. According to the theory, a mechanism of the transition includes the main parameters of the martensitic transformation, namely, the lattice strain and the strain in an invariant lattice. The package of parallel plates that are formed in the course of the transformation is considered as a single martensite crystal. It has been established that the deformation of martensite upon this transition (with an invariant lattice) is aimed at restoring the shape of the initial section of the bcc phase (prototype), rather than at obtaining an invariant plane. The calculation shows that shape restoration in the basal plane of the hcp phase is mainly caused by the action of two systems of prismatic sliding. The sliding is concentrated in narrow layers of localized shear, which leads to the formation of a lamellar structure of the package. The shape restoration along the c axis occurs due to the pyramidal sliding. [ABSTRACT FROM AUTHOR]

First example of a Zr(IV) complex with an aromatic carboxyamidate ligand, Zr(mba)4 (mba = N-methoxybenzamidate), is prepared. Its structures in the solution (1H, 13C{1H} NMR) and in the crystal phase (single-crystal XRD) are determined and compared with those of the initial N-methoxybenzamide Hmba. During the complexation, mba– ligands exhibit a bidentate cyclic function through oxygen atoms. The coordination polyhedron of the metal atom is a distorted square antiprism, the lengths of Zr–O bonds with carbonyl and methoxy groups fall within 2.08-2.09 Å and 2.29-2.33 Å, respectively. Despite the presence of available phenyl rings, the Zr(mba)4 and Hmba crystals contain no intermolecular π–π-interactions, but exhibit C–H⋯π and N–H⋯O contacts, respectively. According to the DSC data, Hmba undergoes no phase transitions from 130 K up to the melting point (335.0±0.5 K, ΔH = 15.1±0.1 kJ/mol, ΔS = 45.2±0.2 J/(mol·K)), while Zr(mba)4 exhibits a reversible solid-phase transition (Tonset = 177.4±0.5 K, ΔH = 0.68±0.20 kJ/mol, ΔS = 3.8±0.1 J/(mol·K)). Studying the Zr(mba)4 crystals at 150 K and 200 K shows that this transition is not accompanied by the crystal deformation and is apparently caused by the rotation of phenyl groups. Due to this conversation, the space group changes from P21/c to P21/n, and one of the unit cell parameters increases by 3 times. [ABSTRACT FROM AUTHOR]

Solar light-induced aqueous crystal violet (CV) dye degradation was carried out on α-zirconium phosphate/graphitic carbon nitride (α-ZrP/g-C3N4) nanocomposite. α-ZrP was synthesized by direct precipitation of zirconium oxychloride with phosphoric acid. g-C3N4 was prepared by thermal decomposition of melamine. α-ZrP/g-C3N4 nanocomposite was synthesized by the direct precipitation of zirconium phosphate on the surface of g-C3N4. Powder X-ray diffraction pattern confirmed the formation of pure α-ZrP, g-C3N4, and α-ZrP/g-C3N4 nanocomposites with crystallite sizes of 51.3 nm, 8.9 nm, and 46.4 nm, respectively. SEM images of α-ZrP showed plate-like morphology and g-C3N4 showed a layered structure with buckled and backfolded edges. XPS and EDX spectrum of the α-ZrP/g-C3N4 nanocomposite shows the presence of Zr, P, N, C, and O elements. The optical absorption wavelength/band gap of the α-ZrP, g-C3N4, and α-ZrP/g-C3N4 nanocomposites were 394.7 nm/3.33 eV, 494.3 nm/2.66 eV, and 457.5 nm/2.85 eV, respectively. The degradation efficiency toward CV dye was found in the order of α-ZrP < g-C3N4 < α-ZrP/g-C3N4 nanocomposite. The degradation efficiency increases with an increase in time, and the pseudo-first-order kinetics model was fitted well. The rate constant of the α-ZrP/g-C3N4 nanocomposite was found four times higher than that of g-C3N4 and ten times of the α-ZrP. The photocatalytic degradation of CV dye under solar light occurred via oxidation by hydroxyl radical and was maximum at pH 6. The photocatalytic degradation efficiency decreases in the presence of anions. α-ZrP/g-C3N4 nanocomposite is easy to synthesize, low-cost, and has high degradation efficiency, making it a promising photocatalyst to clean water containing CV dye under solar light. [ABSTRACT FROM AUTHOR]

Zirconium ions incorporated into the secondary structure of the Keggin type heteropoly tungstate by titration method by varying the zirconium content. The FT-IR, Laser Raman, and XRD analysis of the synthesized catalysts revealed that the incorporation of the zirconium does not affect the primary structure of the Keggin ion. The quantitative acid measurement of the catalysts was done by TPD-NH3 technique. The type of acid site was identified by adsorbing pyridine on the catalyst and qualitative analysis was carried out by DRIFTS. The activity of the catalysts was tested for the glycerol carbonylation using urea as a CO source. The catalyst with moderate content of Zr4+ ions in the secondary structure presented high activity. Catalysts acidity and activity depend on the intact primary Keggin heteropoly tungstate together with the counter ions type and its size in the secondary structure and catalyst calcination temperature. [ABSTRACT FROM AUTHOR]

Gamma emission induced by the irradiation of nickel and zirconium with fission neutrons was investigated with the FaNGaS (Fast Neutron–induced Gamma-ray Spectrometry) instrument operated at Heinz Maier-Leibnitz Zentrum. Measurements were done at an angle of 90° with respect to the direction of the fission neutron beam (average neutron energy of 2.18 MeV). We report on the relative intensities and production cross sections of 265 gamma lines (163 for nickel and 102 for zirconium). Consistency with available literature data was evaluated. The cross section of the 90Zr(n,n′)90mZr reaction was determined to be 88 ± 8 mb. For a counting time of 12 h, the detection limits of 0.7 and 1.3 mg were estimated for nickel and zirconium, respectively. [ABSTRACT FROM AUTHOR]

The selective separation of Zr(IV) from a simulated waste solution containing U(VI) and Zr(IV) was investigated using the extraction method with N,N,N′′′′,N′′′′-tetraoctyl-N′′′,N′′′-(N′′,N′′-diethyl)-ethidene bisdiglycolamide (TOEE-BisDGA) dissolved in n-octanol. TOEE-BisDGA demonstrated outstanding kinetic performance, achieving quantitative (> 99%) and selective extraction of Zr(IV) during the extraction process. Slope analysis indicated the formation of a 1:1 complex between the ligand and Zr(IV). Furthermore, the application of density functional theory calculations confirmed the superior selectivity of TOEE-BisDGA towards Zr(IV) compared to U(VI). [ABSTRACT FROM AUTHOR]

The current work aims to synthesize new zirconium tungstate (Zr4W8O32)-doped ZrO2 composites for radiation shielding applications using the hydrothermal reaction process. The characterization of the synthesized composites was proved using various analysis techniques including X-ray diffraction, scanning electron microscope, transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy. The density of the synthesized Zr4W8O32-doped ZrO2 composites reduced between 5.15 and 4.98 g/cm3, with raising the W concentration between 13 and 28 wt%. Additionally, the average crystallite size proved by TEM analysis was determined as 27.7 nm and 33.2 nm, respectively, for composites ZW-1 and ZW-2. Furthermore, the Monte Carlo N-particle transport code (version-5) was applied to estimate the gamma ray shielding properties of the synthesized zirconium tungstate (Zr4W8O32)-doped ZrO2 composites. The linear attenuation coefficient for the synthesized composites showed variation between 104.50 and 0.200 cm−1 (for ZW-1 composite) and 92.35 and 0.196 cm−1 (for ZW-2 composite) when the gamma photon increased between 0.033 and 2.506 MeV. Therefore, the radiation protection efficiency for a 3 cm thickness of the synthesized composites reaches 54.27% and 53.57% for samples ZW-1 and ZW-2, respectively. As a result, the fabricated composites can be used to produce ceramics with high shielding properties to be used in radiation shielding applications. [ABSTRACT FROM AUTHOR]

In this work, highly ordered ZrO2 nanotube arrays were fabricated on commercial pure Zr substrates through anodic oxidation in the water-based electrolyte at various voltages (30 V, 40 V and 50 V) for 1 h. The monoclinic- and tetragonal-ZrO2 phases were obtained on ZrO2 nanotubes through anodic oxidation. 13 vibration modes have been observed for the samples grown at low voltages (30 V and 40 V), which are assigned to monoclinic symmetry (7Ag + 6Bg), while—with the increasing growth voltage, the dominant phonon peak intensities associated with the monoclinic symmetry 6 times are decreased, and Eg (268 and 645 cm − 1) mode corresponding to tetragonal symmetry is observed. The nanotube array surfaces exhibited hydrophilic and super-hydrophilic behavior compared to the bare Zr surface. The elastic modulus values of ZrO2 nanotube surfaces (14.41 GPa) were highly similar to those of bone structure (10–30 GPa) compared to bare Zr substrate (120.5 GPa). Moreover, hardness values of ZrO2 nanotube surfaces were measured between ∼76.1 MPa and ∼ 283.0 MPa. The critical load values required to separate the nanotubes from the metal surface were measured between ∼1.6 N and ∼26.3 N. The wear resistance of the ZrO2 nanotube arrays was improved compared to that of plain Zr substrate. [ABSTRACT FROM AUTHOR]

The effect of inoculants was confirmed to improve the mass effect of ferritic spheroidal graphite iron castings with heavy sections. In the first series of tests, primary inoculation was performed simultaneously with the spheroidizing treatment, followed by the addition of post-inoculant, and the effectiveness of this method was evaluated in the terms of nodule count and mechanical properties. Post-inoculation is the common term for inoculation after initial treatment. In the first series of tests, six inoculants were evaluated in separately cast test samples, for the second part of the evaluation, Fe–Si–Ca–Zr and Fe–Si–Ca–Ba① were selected. In the second series of tests, these inoculants were used and evaluated by cast on test samples with the wall thickness of 40 and 70 mm. The results showed that possibly the change to Fe–Si–Ca–Zr provided the greatest increase in the nodule count. Tensile properties of samples post-inoculated Fe–Si–Ca–Zr showed almost the same values for tensile strength, proof stress, and elongation at 40 mm and 70 mm wall thickness. In impact tests, differences in absorbed energy were observed in samples with a wall thickness of 70 mm, with Fe–Si–Ca–Zr having the highest absorbed energy. Therefore, the Fe–Si–Ca–Zr inoculant is effective post-inoculation for reducing mass effect. Also, the factors were discussed through electron probe micro analyzer (EPMA) analysis of inoculant. [ABSTRACT FROM AUTHOR]

Effective structural design can make the catalyst have higher specific surface area and dispersed active sites, thus endowing the catalyst higher catalytic efficiency. In this work, magnetic nitrogen-doped carbon nanotube (CNT) was introduced as the support to immobilize the zirconium-based biomass-derived hybrid (Zr-FDCA) through solvothermal method, in which specific surface area had significantly increased to improve the dispersibility of zirconium, thus improving the adsorption over the catalyst to ethyl levulinate (EL). In addition, the introduced nitrogen served as the basic sites to boost the proton transfer in catalytic transfer hydrogenation (CTH) reaction. As a result, the prepared Zr-FDCA@CNT exhibited an ideal catalytic performance in CTH of EL into γ-valerolactone. Gratifyingly, Zr-FDCA@CNT also showed magnetism and good reusability, which could be easily separated from the reaction mixture and no significant loss in the activity after reuse for four runs. [ABSTRACT FROM AUTHOR]

Despite the success of monolithic zirconia restorations (MZ), metal-ceramic restorations (MC) are still considered the gold standard for fixed prosthetics in the posterior region. This systematic review and meta-analysis aimed to compare the fracture strengths of single-unit MC and MZ in the molar region. This review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA, 2020) statement. All articles were searched from the PubMed and Web of Science databases until November 18, 2022. All in vitro studies evaluating the fracture strengths of MC and MZ were also included. Statistical analysis was performed with the Comprehensive Meta-Analysis program, with a significance level of 0.05. Out of 753 studies, five were selected. The fracture strengths of MZ and MC did not show any statistically significant difference for both tooth (95% CI − 1.589: 2.118, p = 0.779, z = 0.280) and implant (95% CI − 2.215: 2.191, p = 0.992 z = − 0.010) supported restorations. However, different abutment materials (p < 0.001) and aging treatments (p < 0.001) in tooth-supported restorations displayed a significant statistical difference. Additionally, a significant difference was also observed in subgroup analysis considering different cements (p = 0.001) and load speeds (p = 0.001) in implant-supported restorations. Fracture strengths of MZ and MC did not show a significant statistical difference in implant or tooth-supported single-unit posterior restorations. MZ may be a suitable alternative to MC in single-unit posterior restorations. The results should be interpreted with caution, as the included studies were in vitro. [ABSTRACT FROM AUTHOR]

In contrast to two-dimensional (2D) monolayer materials, van der Waals layered transition metal dichalcogenides exhibit rich polymorphism, making them promising candidates for novel superconductor, topological insulators and electrochemical catalysts. Here, we highlight the role of hydrostatic pressure on the evolution of electronic and crystal structures of layered ZrS2. Under deviatoric stress, our electrical experiments demonstrate a semiconductor-to-metal transition above 30.2 GPa, while quasi-hydrostatic compression postponed the metallization to 38.9 GPa. Both X-ray diffraction and Raman results reveal structural phase transitions different from those under hydrostatic pressure. Under deviatoric stress, ZrS2 rearranges the original ZrS6 octahedra into ZrS8 cuboids at 5.5 GPa, in which the unique cuboids coordination of Zr atoms is thermodynamically metastable. The structure collapses to a partially disordered phase at 17.4 GPa. These complex phase transitions present the importance of deviatoric stress on the highly tunable electronic properties of ZrS2 with possible implications for optoelectronic devices. Transition metal dichalcogenides exhibit rich polymorphism, making them promising candidates for superconductors, topological insulators, and electrochemical catalysts. Here, the authors study the metallization of non-hydrostatically compressed ZrS2 up to 45.8 GPa and find that a new high-pressure phase forms under deviatoric stress. [ABSTRACT FROM AUTHOR]

This study validates the proposed polymerised structure, including tetrameric polynuclear species, of solid amorphous oxyhydroxide zirconium conversion coatings on cold-rolled steel using ToF-SIMS. Tetramers are formed at pH near 4 (and possibly higher), with thickness increasing over extended conversion times. EIS in simulated acid rain further demonstrates that optimal coating formation requires a pH of at least 4 and a sufficient conversion time for adequate thickness, confirmed by the high-frequency EIS loop. Tetramer forms were not observed when the coatings were prepared at lower pH or shorter conversion time, proving that the polymerisation step is crucial for obtaining the coatings offering adequate corrosion protection. [ABSTRACT FROM AUTHOR]

The deformation behavior of ZrO2 under compression of cylindrical and three point bending of V-notched beam-shaped samples has been investigated. The ceramics possess 50% porosity and the average pore size varying from 10 to 300 μm. It is shown that the formation of stochastic porosity and further increase in the average pore size lead to a multiple strength decrease relative to a non-porous sample. At the same time, the deformation behavior changes from elastic to pseudoplastic one reflected by the appearance of many local minima in the deformation curves and the increase in the relative ultimate strain. A plateau is found in the fracture toughness dependence on the pore size due to the increase in the main crack trajectory running mainly between the pores. In addition, the formation of multiple microcracks is found, also preventing the development of the main crack. [ABSTRACT FROM AUTHOR]

This study aims to investigate the influence of zirconium addition on the corrosion behavior of the FeAl40Ti3B intermetallic alloy, which was synthesized in an arc furnace under argon atmosphere at 950 °C for 2 h and subsequently annealed for 168 h at 500 °C in quartz capsules. Electrochemical techniques, specifically potentiodynamic polarization curves and electrochemical impedance spectroscopy measurements (EIS), were employed to assess the corrosion characteristics. The study also delves into the morphological and phase composition changes through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The addition of zirconium to the FeAlTiB alloy led to the formation of zirconium carbide (ZrC) and other phases, including the Laves phase (Fe,Al)2Zr. The electrochemical behavior in a 0.5 M H2SO4 solution revealed significant improvements in the corrosion potential (Ecorr), current density (icorr), and corrosion rate after the addition of Zr to FeAl40Ti3B. While the corrosion rate for the unalloyed alloy was primarily diffusion-controlled, the alloy with Zr exhibited charge transfer control. Observations via SEM confirmed the occurrence of pitting corrosion in the FeAl40Ti3B alloy, but the addition of zirconium substantially enhanced its corrosion resistance. These findings shed light on the positive impact of zirconium addition on the corrosion resistance of the FeAl40Ti3B alloy, offering valuable insights for potential industrial applications. [ABSTRACT FROM AUTHOR]

The results of studies on the zirconium crystal structure after initial stages of oxidation in an open air at temperature of 700°C for 15 min are presented. Samples of commercial pure zirconium with a minimal content of impurity atoms as well as chromium-alloyed zirconium have been studied by means of the action of compression plasma flows. The possibility of alloying the zirconium near-surface layer with chromium, with a chromium coating thickness of 1 μm, by means of compression plasma flows with the absorbed energy density of 25–43 J/cm2 has been demonstrated. Stabilization of the high-temperature zirconium β phase in the form of β-Zr(Cr) solid solution and intermediate martensite α'-Zr phase has been observed. After isothermal annealing of zirconium samples at T = 700°C and irradiated with plasma flow with Qmax = 43 J/cm2, no effect of the surface layer alloying with chromium atoms has been observed owing to its intense evaporation and ablation in the course of surface heating by plasma flow, as well as increased resistance to high-temperature oxidation at the initial stages in comparison with the initial state. [ABSTRACT FROM AUTHOR]

The structural and phase state of the surface layers of Al, Al-Si, and Al-Si-Cu-Mg alloys doped with zirconium atoms under the influence of compression plasma flows is studied. It is established that metastable compounds Al3Zr with the crystal structure L12 and (Al, Si)3Zr with the structure D022 are formed in the doped layers of aluminum and silumins, respectively. It is shown that doping of the studied alloys with zirconium makes it possible to increase the microhardness of the surface layer by 1.4–3 times. A study of the thermal stability of the structural and phase state of the doped layers at 550°C showed that, as a result of aluminum annealing, the Al3Zr phase with the L12 structure transforms into the Al3Zr compound with the D023 structure, and in the alloys of the Al–Si system, the decomposition of (Al,Si)3Zr and the formation of ZrSi2 occur. It is noted that the synthesized surface layer has increased temperature strength. [ABSTRACT FROM AUTHOR]

The process of precipitation of Al3Zr particles in cast Al–(0.25–0.4) wt % Zr alloys manufactured by the induction casting method is studied. The effect of zirconium concentration on the structural parameters, hardness, and specific electrical resistance (SER) of cast alloys is investigated. The dependences of hardness and SER on the time of cast alloys annealing at 500°C are plotted. The parameters of the Johnson–Mehl–Avrami–Kolmogorov equation for alloys with different Zr content are determined. The optimal regimes of cast ingot aging are found. Fine wires with ∅0.3 mm are manufactured by the drawing method; their strength, SER, and hardness are studied in the initial state and after heat treatment. The tests of thermal stability of wires are carried out according to the state standard GOST R MEK 62004–2014. [ABSTRACT FROM AUTHOR]

Converting carbon dioxide into value-added products is one of the most important inventions to solve global warming and energy demand. Herein, we prepared a series of Zr-doped CeO2 catalyst (Ce1Zrx, x = 0.01, 0.05 and 0.2) for the catalytic production of ethylene urea (EU) from ethylenediamine (EDA) and CO2. Several characterization techniques, such as XRD, FTIR, Raman, TEM, N2 adsorption, CO2-TPD and XPS, were used to investigate the relationship between catalytic activity and structural characteristics, especially the doping form and promotion mechanism of Zr in CeO2 lattice. The results present that the Ce1Zr0.01 catalyst revealed excellent catalytic activity with 91.5% EDA conversion and 100% EU selectivity and cyclic stability in comparison with undoped CeO2. The doped Zr was beneficial to the formation of enriched defects and led to more oxygen vacancies and weak basic sites, thus enhancing CO2 adsorption and activation. This work laid a foundation for the design of highly active catalysts for the synthesis of EU from CO2 and EDA. [ABSTRACT FROM AUTHOR]

Aluminum alloy wire rod is the basic material for manufacturing wires for overhead power lines constructed in the areas with different atmospheric conditions. There is a potential associated with the use of wire rods made of aluminum-zirconium alloys, which can improve the performance characteristics of the final products. This study is devoted to a method for determining rheological coefficients of the equation linking the strength properties (σs) of alloy Al–0.15Zr with deformation parameters ( and ξ) at process temperatures ranging from 300 to 500 °C. The coefficients were calculated based on the experimental data obtained during indirect determination of the deformation resistance by measuring the force of direct hot extrusion. The variable parameters of the experiment included: elongation ratio (λ), deformation temperature (T), and extrusion velocity (υex). For each equation coefficient, characteristic curves demonstrating their dependence on the process temperature were plotted and used to find an approximating function. [ABSTRACT FROM AUTHOR]

We report the effect of titanium doping on the structure, morphology, dielectric and electrical properties of zirconium ferrite Zr1−xTixFe2O4 (x = 0.0, 0.01, 0.03, 0.05) nanocrystalline ceramics prepared via sol–gel method. X-ray diffraction (XRD) technique confirmed the spinel structure of all samples and that the average crystallite size decreased with Ti doping. Scanning electron microscopy (SEM) confirmed the spherical-shaped morphology with an average grain size of 300 and 200 nm for x = 0 and 0.05, respectively. The Raman study revealed that Ti4+ substitution slightly shifts the Raman modes towards the lower wavenumber. The dielectric studies analyzed using Impedance analyzer show the increase in dielectric parameters such as dielectric constant and dielectric loss with Ti concentration. The complex impedance analysis in the frequency range (10–106 Hz) is analyzed to understand the interactions from the grain and grain boundary phases. The dielectric feedback and impedance analysis studied the electrical properties in the 300–700 K temperature range and frequency range of 20–106 Hz. The AC conductivity increases with applied frequency and decreases with doping concentration. It is found that the Ti concentration increases the activation energy determined using the Arrhenius equation of AC conductivity and is a characteristic of polaron conduction. The Universal power law dependency of AC conductivity indicates charge transport made possible by hopping or tunneling. The temperature-dependent frequency exponent n's observed minimal implies that the major transport mode is significant polaron tunneling. [ABSTRACT FROM AUTHOR]

Zirconium−incorporated manganese oxide octahedral molecular sieve (Zr−OMS−2) was fabricated through a reflux method and applied to decompose tetracycline (TC) in an aqueous solution by peroxydisulfate (PDS) activation. The characteristics of Zr−OMS−2 was studied by Fourier transform infrared spectroscopy (FT−IR), X−ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), N2 adsorption−desorption isotherms, and X−ray photoelectron spectroscopy (XPS). Under the optimized conditions, the TC degradation efficiency in the Zr−OMS−2/PDS system was 94.7% within 50 min, which was almost twice the degradation efficiency in presence of pure OMS−2 under the same conditions (52.3%). This system showed satisfactory performance over a wide range of pH (2−9). The results of radical trapping experiments proved that the removal of TC can be attributed to the generation of HO• and SO4•− free radicals. Additionally, the catalyst demonstrated satisfactory stability and reusability during four consecutive cycles. [ABSTRACT FROM AUTHOR]

Background: Sodium zirconium cyclosilicate (SZC) is an approved oral treatment for hyperkalemia that selectively binds potassium (K+) in the gastrointestinal tract and removes K+ from the body through increased fecal excretion. Here, we describe the population pharmacodynamic (PopPD) response of serum K+ concentration in patients with hyperkalemia who are treated with SZC, estimate the impact of patients' intrinsic and extrinsic factors, and compare predicted serum K+ responses between 5 g alternate daily (QOD) and 2.5 g once daily (QD) maintenance doses. Methods: PopPD analysis was based on pooled data from seven phase II and III clinical trials for SZC. A semi-mechanistic longitudinal mixed-effects (base) model was used to characterize serum K+ concentration after SZC dosing. Indirect-response, virtual pharmacokinetics–pharmacodynamics (PK–PD) modeling was used to mimic the drug exposure compartment. Full covariate modeling was used to assess covariate impact on the half-maximal effective concentration of drug (EC50), placebo response, and Kout. Models were evaluated using goodness-of-fit plots, relative standard errors, and visual predictive checks, and data were stratified to optimize model performance across subgroups. Covariate effects were evaluated based on the magnitude of change in serum K+ between baseline and end of correction phase dosing (48 h, SZC 10 g three times a day) and maintenance phase dosing (28 days, SZC 10 g QD) using a reference subject. Results: The analysis data set included 2369 patients and 25,764 serum K+ observations. The mean (standard deviation) patient age was 66.0 (12) years, 61% were male, 68% were White, 34% had congestive heart failure, and 62% had diabetes. Mean (standard deviation) serum K+ at baseline was 5.49 (0.43) mmol/L. Both the base and full covariance models adequately described observed data. In the final model, there was a sigmoid exposure response on Kin, with EC50 of 32.8 g and a Hill coefficient of 1.36. The predicted placebo-adjusted dose–responses of serum K+ change appeared nearly linear in the correction and maintenance phases. No clinically meaningful difference in placebo-adjusted serum K+ change from baseline at 28 days was observed between maintenance regimens of SZC 5 g QOD and 2.5 g QD. A greater SZC treatment response was associated with high serum K+ at baseline, advanced age, lower body weight, lower estimated glomerular filtration rate, and Black/African American and Asian race, compared with the reference patient. The impact of heart failure status and diabetes status was only minor. Conclusions: The PopPD model of SZC adequately described changes in serum K+ concentration during correction and maintenance phase dosing. A greater treatment response was associated with various covariates, but the impact of each was modest. Overall, these findings suggest that no adjustment in SZC dose is needed for any of the covariates evaluated. [ABSTRACT FROM AUTHOR]

The comparative corrosion resistance and electrochemical behavior in acidic, alkaline, and neutral media of both pure metals and the Ni–Re alloys doped with zirconium, hafnium, tungsten, and palladium were investigated. A positive effect of zirconium on the corrosion resistance of the Ni–Re alloy in all studied media was demonstrated. It is shown that the Ni–Re alloy doped with hafnium also improves corrosion resistance and compensates its reduction at introduction to a tungsten alloy. It is shown that the Ni–Re alloy doped with zirconium together with palladium has the maximum corrosion resistance. [ABSTRACT FROM AUTHOR]

The crystal and molecular structure of a polynuclear pivalate complex obtained by the interaction of ZrCl4 with pivalic acid is determined by X-ray diffraction analysis. The compound C71H124O28Zr4 crystallizes in a monoclinic crystal system. The crystal structure is refined in the nonstandard space group I2. The asymmetric part of the structure includes three Zr atoms, six pivalate ligands, and a bridging µ3-O oxygen atom, as well as disordered crystallization molecules of pivalic acid with an occupancy of 50% and benzene with an occupancy of 50%. The zirconium complex molecule is a tetranuclear cluster that contains three types of Zr atoms that differ in the ligand environment. A comparison of the results of the quantum chemical calculations of the model reaction of ZrCl4 with acetic acid with the published data on reactions of ZrCl4 with aliphatic acids shows the possibility of the formation of both mononuclear Zr(RCO2)4 and polynuclear clusters in this reaction, which is a new route for obtaining polynuclear zirconium clusters. The structure of the clusters formed depends on the steric properties of carboxylate ligands. [ABSTRACT FROM AUTHOR]

Zirconium dioxide samples with different crystallinity and phase compositions have been obtained by calcination of a mixture of zirconium oxychloride and sodium bicarbonate at temperatures ranging from 150 to 800°C. It is established that amorphous ZrO2 with an zirconium oxycarbonate admixture is formed at 150-200°C. A sample obtained at 400°C contains 50% of the tetragonal phase and 50% of the amorphous ZrO2 phase, while a mixture of tetragonal and monoclinic phases is formed at 600°C and 800°C (83% of t-ZrO2/17% m-ZrO2 and 27% of t-ZrO2/73% m-ZrO2, respectively). It is shown that zirconium dioxide obtained at 150°C has the highest efficiency of adsorptive removal of phosphate anions from an water solution as compared with other studied samples. [ABSTRACT FROM AUTHOR]

The objective of this research is to investigate the effect of palladium insertion into zirconium(IV)-based Metal-Organic Frameworks (MOFs) containing a benzene 1,3,5-benzenetricarboxylate organic linker [Pd/Zr6O4(OH)4(O2C2H3)6(BTC)2] or (Pd/Zr-BTC) on its structure and its ability to catalyze the hydrogenation process of citronellal. Zr-BTC was synthesized by a modulated-solvothermal method at 135 °C. Post-synthesis modification with Pd nanoparticle was conducted using the wet impregnation method with a concentration of 2.5% (w/w). Powder XRD analysis showed that the presence of Pd was identified by a new peak at 2θ = 40.0° and the decrease of Zr-BTC crystallinity. The presence of Pd also increases the irregularity of Zr-BTC morphology and contains an average particle size up to 16.58 ± 6.4 nm according to SEM and TEM analysis. Modification with Pd lead to a decrease in surface area, pore volume, and diameter of Zr-BTC up to 1095 m2/g, 0.15 cc/g, and 18.6 Å, respectively. Moreover, the addition of Pd does not affect the thermal stability of Zr-BTC. An examination of the hydrogenation of citronellal was carried out using two distinct setups. The first involved conducting reactions in a batch reactor system at a temperature of 80 °C and under a hydrogen pressure of 10 bar for a duration of 6 h. The second approach entailed performing reactions in a hydrogen-filled balloon under atmospheric pressure (1 atm) at 80 °C for a period of 6 h. The addition of Pd into Zr-BTC increases its activity up to 83.2%, and selectivity (up to 53.7%) in citronellal hydrogenation for both batch and balloon systems. Interestingly, the employment of batch reactors is found to be more effective. [ABSTRACT FROM AUTHOR]

There are many great uses for heavy elements that are expanding daily and generating enormous amounts of effluents. Therefore, tremendous scientific efforts in removing, recovering, and recycling them are carried out to prevent these harmful effects on the environment and human health. The polyacrylic-carboxymethyl cellulose-trioctyl amine/reduced graphene oxide adsorbent (AA-CMC-TOA/rGO) was synthesized as a promising sorbent for Zr4+ and Y3+ ions by gamma irradiation for a mixture of acrylic acid, carboxymethyl cellulose, and trioctyl amine as an organic solvent. A complete characterization of the manufactured composite was carried out to find out its chemical and physical properties several techniques such as XRD, EDX, SEM, FT-IR, TGA-DTA, and BET. Several factors affecting the Zr4+ and Y3+ adsorption processes were studied to set the best conditions that achieve the extreme loading capacity of Zr4+ and Y3+ ions. Loading capacities of 0.99 and 1.07 mmol g−1 were achieved for Zr4+ and Y3+, respectively. The results of the kinetic models indicated that the adsorption reactions of Zr4+ and Y3+ ions were carried out via a chemical reaction mechanism. Langmuir, Dubinin–Radushkevich, and Redlich–Peterson models accurately described the adsorption isotherm data by proving their chemical nature. The results of thermodynamics added evidence of the chemical nature, spontaneous, and endothermic nature of the adsorption processes. A complete retrieval for Zr4+ and Y3+ ions contents located in the effluent was efficiently achieved using AA-CMC-TOA/rGO sorbent which proved its uses as a promising sorbent. [ABSTRACT FROM AUTHOR]

This research aims to transform crude palm oil (CPO) into biofuels through a catalytic hydrocracking method using a SiO2–ZrN catalyst prepared by the chelate-assisted EDTA (ethylenediaminetetraacetic acid), denoted as SiO2–ZrN2 and KHP (potassium hydrogen phthalate), denoted as SiO2–ZrN3 catalysts, respectively. The as-prepared catalysts were characterized using XRD, FTIR, SEM-EDX mapping, PSA, gravimetric acidity analysis, and N2 adsorption–desorption. The transformation of SiO2–Zr to SiO2–ZrN through the nitriding treatment was able to change the particle size distribution of the catalyst from heterogeneous to homogeneous, as well as enhance the acidity the acidity and textural features with a highly dispersed ZrN on the silica. CPO hydrocracking test revealed that SiO2–ZrN prepared by chelate-assisted EDTA and KHP achieved high catalytic activity towards CPO hydroconversion followed by high liquid and low coke formation with an adequate stability performance. SiO2–ZrN successfully suppressed the formation of long-chain into short-chain hydrocarbon. Both SiO2–ZrN2 and SiO2–ZrN3 each exhibited a high fraction towards aviation fuel compared to parent SiO2 and SiO2–Zr. [ABSTRACT FROM AUTHOR]

Strontium zirconium phosphate (SrZr4(PO4)6) ceramics has high density and chemical inertness, which can safely and effectively immobilize the divalent fission product Sr in the ceramic matrix. In this study, a novel SrZr4(PO4)6 ceramic was synthesized using microwave sintering of uranium tailings. This method features shorter sintering times and efficient energy use. Sr replaces Na in sodium zirconium phosphate (NaZr2(PO4)3) due to similar ionic radii, transforming it into SrZr4(PO4)6 ceramics. The results showed that the sintered samples prepared by holding at 1200 °C for 50 min, which the density of the solidified body reached up to 3.2 g/cm3.The ceramics showcase outstanding leach resistance, with Sr leaching rates far below the nuclear industry standard (1 × 10−2 g m−2 d−1). Similarly, the leaching rates for Na, Zr, P, and Si (10–4–10–6, 10–6–10–8, 10–3–10–4, and 10–2–10−3 g m−2 d−1) are significantly lower than industry standards. [ABSTRACT FROM AUTHOR]

Amorphous coordination polymers (CPs) are one of the important classes of porous materials, that are gaining attention and providing us with an exciting opportunity to synthesize novel functional materials. Amorphous CPs have practical applications in the domain of material science for a wide range of applications, including biomedical, supercapacitors, gas storage, drug delivery, pollution control, and many others. Though several metal ions and ligands are available, the synthesis of CP with a biocompatible metal ion zirconium and a bidentate ligand, an amino acid (L-Asparagine) offers an eco-friendly CP with high surface area for a variety of applications. Herein, we report the synthesis of amorphous Zr-CPsAsn using three different pH conditions using modifiers namely, acid, base, and neutral which are thermally stable up to 250 °C. The role of pH modifiers in tuning the surface and pore environment is studied in detail using the BET, FESEM, and EDX analyses and the results are compared. It is interesting to the role of an acidic modifier, which tunes the surface area, and the basicity improves the pore environment, comparatively. Amorphous CPs and innovative synthesis have received attention in recent studies because of their potential and possible applications in a variety of material sciences fields, specifically, heavy metal ion adsorption in water remediation. [ABSTRACT FROM AUTHOR]

Titanium and zirconium alloys are indispensable structural materials in many technical applications due to their unique mechanical and physicochemical properties. Titanium and zirconium belong to the fourth ("titanium") group, due to which one would expect them to exhibit a similar character of hydrogen permeability through alloys of these metals. The results of experiments on the hydrogen permeability of these alloys are compared and analyzed. It is revealed that the hydrogen permeation kinetics for both alloys is mainly determined by the low rate of surface processes and phase transformations, occurring as a result of increasing hydrogen concentration. It is shown that the hydrogen permeability method can be used to find the terminal solid solubility of hydrogen in metals. [ABSTRACT FROM AUTHOR]

Phase formation in cast stone matrices (CSMs) fabricated through the interaction of comelted basalt with ZrO2 at 1623 K for 5 h on air was studied. Basalt melted under the above conditions contains two spinels (relict and newly formed), clinopyroxene of the composition Mg0.66Ca0.60Fe0.26Ti0.05Al0.66Si1.80O6, and glass as the major phases. When basalt is comelted with ZrO2, taken in a weight ratio of 1 : 1, CSMs containing zircon (ZrSiO4), glass, and baddeleyite (ZrO2) as the major phases are formed. Zirconium is concentrated mainly in two phases, zircon and baddeleyite. The rate of Zr leaching from the synthesized CSMs into H2O after 28 days is ~1.0 × 10–9 g/(cm2 day). [ABSTRACT FROM AUTHOR]

The available experimental data for the density, thermal conductivity, and viscosity of liquid titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten have been critically examined with the intention of establishing reference correlations. All experimental data have been categorized into primary and secondary data according to the quality of measurement, the technique employed, and the presentation of the data, as specified by a series of criteria. In the case of the density, new reference correlations are proposed for liquid titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten, characterized by an expanded uncertainty (95 %) of 2.0 %, 2.1 %, 1.9 %, 2.2 %, 2.4 %, 2.6 %, 3.2 %, 2.1 %, and 4.1 %, respectively. The thermal conductivity reference correlations for the aforementioned liquid metals, except liquid chromium, are characterized by an expanded uncertainty (95 %) of 14.3 %, 8.4 %, 6.1 %, 11.4 %, 7.6 %, 4.0 %, 4.6 %, and 5.1 %, respectively. Finally, in the case of the viscosity, a review of the available literature shows very large deviations between data from authors for liquid titanium and zirconium, as well as a lack of measurements for the remaining melts. Hence, it is not justified to propose any kind of correlation for those cases. [ABSTRACT FROM AUTHOR]

The synthesis, characterization, and reactivity of several group 4 metal complexes featuring a central anionic pyrrole moiety connected via CH2 linkers to two phosphine donors is described. Treatment of [P(NH)P-iPr] with [MCl4(THF)2] (M = Zr, Hf) in the presence of base yields the dimeric complexes [M(PNPiPr)(μ-Cl)(Cl)2]2 featuring two bridging chloride ligands. These complexes react with sodium cyclopentadienyl and SiMe3I to give the mononuclear complexes [M(PNPiPr)(η5-Cp)(Cl)2] and [M(PNPiPr)(I)3], respectively. The latter react with MeMgBr to form the trialkyl complexes [M(PNPiPr)(Me)3]. Upon treatment of [Ti(NMe2)4] with [P(NH)P-iPr] a complex with the general formula [Ti(PNPiPr)(NMe2)3] is obtained. DFT calculations revealed that the most stable species is [Ti(κ1N- PNPiPr)(NMe2)3] featuring a κ1N-bound PNP ligand. When [P(NH)P-iPr] is reacted with [Ti(NMe2)4] in CH2Cl2 complex [Ti(PNPiPr)(Cl)2(NMe2)] is formed. Treatment of a solution of [P(NH)P-iPr] and [Zr(NMe2)4] with SiMe3Br affords the anionic seven-coordinate tetrabromo complex [Zr(PNPiPr)(Br)4][H2NMe2]. The corresponding hafnium complex [Hf(PNPiPr)(Br)4][H2NEt2] is obtained in similar fashion by utilizing [Hf(NEt2)4] as metal precursor. All complexes are characterized by means of NMR spectroscopy. Representative complexes were also characterized by X-ray crystallography. [ABSTRACT FROM AUTHOR]

In this study, in situ titanium diboride particles were synthesized using boron oxide and titanium oxide to reinforce Al 5083 alloy. Stir casting was used to fabricate this composite. The reinforcement particles were formed in situ inside the melt. The working temperature selected for melting and casting was 80 °C. The effect of cerium oxide, cerium oxide + cryolite, and cerium oxide + cryolite + zirconium additives on the composite was investigated. The results showed that cerium oxide decreased the agglomeration of reinforcing particles in the melt. Cryolite prevented melt oxidation, increased melt flow, and improved the distribution of reinforcing particles in the composite. Zirconium caused the refinement of the structure, decreased the agglomeration of TiB2 particles, and increased the tensile strength of the composite. In addition, the dominant fracture mode in samples modified by cryolite + Zr. CeO2 + cryolite + Zr caused ductile fracture, while in samples modified by CeO2 and CeO2 + cryolite, the brittle fracture was ruling. [ABSTRACT FROM AUTHOR]

Nanostructured thin films on a silicon substrate were obtained by high-frequency periodic pulse f ~ 6–10 kHz action of laser radiation with wavelength λ = 1.064 μm and power density q = 120 MW/cm2 on zirconium in a vacuum chamber at pressure p = 2.2 Pa. The morphology of the thin films of zirconium was studied by atomic-force microscopy. The transmission spectra of the zirconium films in the visible and near and mid IR regions were obtained. The electrophysical characteristics of the Zr/Si structures were analyzed. [ABSTRACT FROM AUTHOR]

Data on the mixing enthalpies of liquid alloys in ternary Me–Ti–Zr (Me = Fe, Co, Ni, Cu) systems and boundary binary systems are summarized. The partial mixing enthalpies of titanium and zirconium and the integral mixing enthalpy of liquid Co–Ti–Zr alloys were investigated for the first time by high-temperature calorimetry at 1873 K along the xCo/xTi =3 section at xZr = 0–0.57 and xCo/xZr = 3 section at xTi = 0–0.54. It was shown that the investigated partial and integral functions were characterized by significant negative values. The isotherms of the integral mixing enthalpy of liquid Fe–Ti–Zr alloys at 2173 K and liquid Co–Ti–Zr alloys at 1873 K are described using the Redlich–Kister–Muggianu polynomial. A new description for the liquid Cu–Ti–Zr alloys at 1873 K is also presented. The negative values and composition dependence of the ∆mH function for liquid alloys of each ternary system are determined by the predominant influence of MeTi and MeZr pair interactions, in which iron, cobalt, nickel, and copper are electron acceptors, while titanium and zirconium are donors. In the considered series of the binary Me–Ti and Me–Zr systems and ternary Me–Ti–Zr systems, the absolute values of the integral mixing enthalpy of liquid alloys increase in the transition from the iron systems to the nickel systems and are minimal in the systems with copper. [ABSTRACT FROM AUTHOR]

The effect of aging time of V/Zr-based conversion bath on coating formation and corrosion resistance ability was investigated. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to investigate the morphology and composition of the conversion coating. Neutral salt spray (NSS), electrochemical impedance spectroscopy (EIS), and Tafel polarization tests were used to characterize the corrosion resistance of the conversion coating. The results showed that as the aging time of the solution increased, V ions were more completely hydrolyzed and converted to VO3− ions, and the presence of VO3− promoted the formation of the conversion coating. In addition, the vanadium element in the conversion coating tends to exist in the form of V2O5, and the proportion of V2O5 increases with the aging time of the conversion bath. The increase in aging time of the conversion bath also has a positive effect on improving the corrosion resistance of V/Zr-coated aluminum alloys. [ABSTRACT FROM AUTHOR]

The Nyong catchment is the second major catchment in Cameroon. Twenty-six (26) stream sediment samples collected from two watersheds (Nlong Mefok and Mbem) from the Nyong catchment to determine the weathering intensity, the provenance of sediments, and the titanium and zirconium (Zr) potentialities. The region is under an equatorial climate of four seasons. This zone is located within the Pan-African Orogeny. The X-ray diffraction results of bulk stream sediments encompass quartz, rutile, ilmenite, muscovite, illite, zircon, and feldspars. The heavy mineral fractions highlight the presence of andalusite and tourmaline, and confirm that of rutile, zircon, and ilmenite. The X-ray fluorescence data present dominance of silica dioxide, iron oxide, and titanium dioxide (TiO2). Inductively coupled plasma-mass spectrometry data also present abundance of vanadium, chromium, copper (Cu), Zr, niobium, tin, hafnium, and light rare earth element. These samples revealed high weathering intensity of source rocks. The high depletion of alkali and alkaline earth elements is also linked to the weathering of rocks as well as the fluvial transport. The thorium/Cu (2.7, 1.73, upper continental crust = 0.61) and lanthanum/scandium (1.15, 0.30) values highlight mixed provenance of the source rocks. TiO2 and Zr contents and the grain sizes found in our samples could be used as reference indices for future exploitation for rutile and zircon. [ABSTRACT FROM AUTHOR]

Surface modification with alginate (Alg) has attracted significant attention because of its potential applications in non-biofouling surface preparation, tissue engineering, and drug delivery. Much effort has been made to develop facile methods for preparing stable Alg coatings, including metal ion-mediated cross-link formation between polydopamine-coated solid surfaces and Alg. Although this approach has yielded Alg coatings that strongly inhibit platelet adhesion and fibrinogen adsorption on solid surfaces, their long-term stability, which is a prerequisite for practical applications, remains unknown. This study evaluated the long-term stability of Alg coatings under physiological conditions. The Alg coatings were incubated in phosphate-buffered saline at 37.5 °C for up to four weeks and subsequently analyzed for non-biofouling properties. The analysis revealed that the anti-protein adsorption and antiplatelet adhesion properties of the Alg coating were maintained at 80 and 90%, respectively, after four weeks of incubation. This study provides valuable insights into the long-term stability of Alg coatings and their potential for practical applications, addressing an overlooked crucial aspect. The findings contribute to advancements in tissue engineering, drug delivery systems, and other biomedical applications by enhancing our understanding of Alg coatings' durability and guiding the design of robust non-biofouling materials. The long-term stability of alginate (Alg) coatings under physiological conditions is evaluated. Alg coatings are prepared using metal ion-mediated cross-link formation and subject to four weeks of incubation in phosphate-buffered saline at 37.5 °C. The Alg coatings maintain their antiprotein adsorption and antiplatelet adhesion properties at high percentages of up to 80% and 90%, respectively. [ABSTRACT FROM AUTHOR]

Experimental results for hydrides reorientation in unirradiated E635 guide tubes are presented. The key parameter for reorientation–the threshold stress was found. Some features of microstructure of hydrides with different orientation are discussed. For cooling rates, which are specific for active zones of pressurized water reactors, δ-hydride is shown to be the only phase that occurs. [ABSTRACT FROM AUTHOR]