Titanium Content Research Articles

Titanium Suboxide-Based Composite Electrocatalysts: Physico-Chemical and Semiconductor Properties

Titanium dioxide is one of the main products of chemical industry. Due to its optical properties, it is most widely used in the paint and varnish industry and the production of pigments. Its sensory, adsorption, optical, electrical, and catalytic properties are widely recognized as the objects of close attention of researchers [1].Due to its high chemical inertness, lack of toxicity and low cost, titanium dioxide is increasingly used as a photocatalyst, while it has a number of significant disadvantages: low quantum efficiency of the process due to weak separation of the electron-hole pair, limited absorption spectrum in the ultraviolet region, which makes it impossible to use the energy of sunlight [2,3]. Scientists in all leading countries of the world are engaged in solving these problems.It is known that nanosized TiO2 particles (<50 nm) have the highest photocatalytic activity; therefore, the preparation of TiO2 nanoparticles is one of the ways to reduce the degree of charge recombination and increase the active surface area of the oxide [4].We propose to use a combined electrochemical-pyrolytic method of nanotube synthesis. This method will allow one to create a porous developed surface of the matrix for electrodeposition of catalytic layers of platinum and palladium; and their subsequent heat treatment at different partial pressures of oxygen will allow one to design composites with different composition. The high number of cationic vacancies in the matrix and the deficiency of oxygen ions will significantly increase the mobility of platinum and palladium atoms during heat treatment, and the resulting composite will have practically metal conductivity, high catalytic activity, selectivity and extended service life.Naked Ti/TiO2 contain a significant amount of X-ray amorphous compounds on the surface, which are most likely hydrated titanium oxides. The main crystalline phase is titanium dioxide in the allotropic anatase form. Metallic titanium is present on the surface in trace amounts. Thermal treatment of this material at a temperature of 500 ºC for 3 hours in an air atmosphere leads to an increase in the proportion of the crystalline phase. The content of metallic titanium increases significantly, reaching about a third. A partial electrochemical reduction of nanotubes allows one to obtain more electrically conductive titanium suboxides. After cathodic reduction of nanotubes for one hour, a galvanic coating with metallic platinum is uniformly deposited on the surface of the material. Thermal treated Ti/TiO2 nanotubes is an n-type semiconductor with a flat-band potential equal to –0.589 V and a carrier concentration of 6×1020 cm-3. Such a high concentration of carriers is obviously due to the small thickness of the oxide film and its nonstoichiometry, as a result of which the surface is not very depleted in electrons, since titanium metal acts as their donor.An original technique was developed for the deposition of platinized Ti/TiO2 nanotubes, including the stage of thermal treatment of the coating in an air atmosphere. It has been shown that the deposition of platinum on the previously reduced surface of nanotubes allows one to obtain composite coatings with a higher electrical conductivity, and the heat treatment of such a coating is characterized by the content of a larger fraction of TiO2, increased adhesion to the current collector, and an increase in the crystallinity of the coating. At the same time, the internal stresses of the coating are reduced by several times. References V.R.A. Ferreira, P.R.M. Santos, C.I.Q. Silva, M.A. Azenha. Latest developments on TiO2-based photocatalysis: a special focus on selectivity and hollownes for enhanced photonic efficiency, Appl. Catal., A, 623, 118243 (2021).S. Palmas, L. Mais, M. Mascia, A. Vacca. Trend in using TiO2nanotubes as photoelectrodes in PEC processes for wastewater treatment, Curr. Opin. Electrochem., 28, 100699 (2021).E. Brillas. A critical review on ibuprofen removal from synthetic waters, natural waters, and real wastewaters by advanced oxidation processes, Chemosphere, 286, 131849 (2022).M. Bellardita, A. Di Paola, L. Palmisano, F. Parrini, G. Buscarino, R. Amadelli, Preparation and photoactivity of samarium loaded anatase, brookite and rutile catalysts, Appl. Catal., B, 104, 291-299 (2011).

Multiple metals exposure and blood mitochondrial DNA copy number: A cross-sectional study from the Dongfeng-Tongji cohort

ObjectiveMitochondria are essential organelles that execute fundamental biological processes, while mitochondrial DNA is vulnerable to environmental insults. The aim of this study was to investigate the individual and mixture effect of plasma metals on blood mitochondria DNA copy number (mtDNAcn). MethodsThis study involved 1399 randomly selected subcohort participants from the Dongfeng-Tongji cohort. The blood mtDNAcn and plasma levels of 23 metals were determined by using quantitative real-time polymerase chain reaction (qPCR) and inductively coupled plasma mass spectrometer (ICP-MS), respectively. The multiple linear regression was used to explore the association between each metal and mtDNAcn, and the LASSO penalized regression was performed to select the most significant metals. We also used the quantile g-computation analysis to assess the mixture effect of multiple metals. ResultsBased on multiple linear regression models, each 1% increase in plasma concentration of copper (Cu), rubidium (Rb), and titanium (Ti) was associated with a separate 0.16% [β(95% CI) = 0.158 (0.066, 0.249), P = 0.001], 0.20% [β(95% CI) = 0.196 (0.073, 0.318), P = 0.002], and 0.25% [β(95% CI) = 0.245 (0.081, 0.409), P = 0.003] increase in blood mtDNAcn. The LASSO regression also confirmed Cu, Rb, and Ti as significant predictors for mtDNAcn. There was a significant mixture effect of multiple metals on increasing mtDNAcn among the elder participants (aged ≥65), with an approximately 11% increase in mtDNAcn for each quartile increase in all metal concentrations [β(95% CI) = 0.146 (0.048, 0.243), P = 0.004]. ConclusionsOur results show that plasma Cu, Rb and Ti were associated with increased blood mtDNA, and we further revealed a significant mixture effect of all metals on mtDNAcn among elder population. These findings may provide a novel perspective on the effect of metals on mitochondrial dysfunction.

The role of Ti in cavitation erosion and corrosion behaviours of NAB alloy in 3.5 % NaCl solution

The influence of titanium on the cavitation erosion and corrosion behaviors of a NAB alloy in 3.5 % NaCl solution is investigated using tensile test, mass loss, SEM, Tafel plots, electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The results show that the NAB alloy consists of the α phase, β phase and κ phase, in which titanium will enter the κ phase to form the titanium-rich κ phase. With the increment of titanium, the titanium-rich κ phase changes from mainly distributed at grain boundaries to more dispersed at grain boundaries and inside grains. In the case of high titanium content, the κ phase rich in titanium grows and produces an obvious segregation phenomenon, resulting in a decrease in the mechanical property and corrosion resistance of the substrate. The mass loss experiment shows that the mass loss caused by cavitation erosion decreases with increasing titanium content, and it increases with increasing titanium content when titanium content is over 0.478 %. The electrochemical experiments show that the corrosion resistance of NAB alloy in 3.5 % NaCl solution increases with increasing titanium content and reaches a maximum when titanium content is 0.478 %. The reason for the increased corrosion resistance of a NAB alloy containing titanium in 3.5 % NaCl solution is related to the appearance of TiO2 in the passive film automatically formed on a NAB alloy in air.

Mafic dikes of the Mariinsky Taiga Alkaline Province, Kuznetsk Alatau terrane, southwestern Siberia: Intraplate alkaline magmatism in the Central Asian Orogenic Belt

The Mariinsky Taiga Alkaline Province (MTAP) is located in the Kuznetsk Alatau terrane of southwestern Siberia, which is part of Altai-Sayan orogenic system, of the Central Asian Orogenic Belt. The MTAP consists of a wide distribution of Paleozoic alkaline-basite magmatism (volcanic, subvolcanic and intrusive), which has been recently characterized with the recognition of at least two main timings, ca. 500 and ca. 400 Ma (herein labeled MTAP-1 and MTAP-2, respectively). We newly characterize the petrology, geochemistry, and age constraints of NNW and NNE trending alkaline dikes which cross-cut the alkaline intrusions and host volcanogenic and carbonate units and which are inferred to belong to MTAP-2. The dikes consist of ultrabasic foidolites (urtites, urtite-porphyry, ijolite-porphyry, microijolites), basic foidolites (plagioclase ijolites), alkaline basites (gabbro-diabase, labradorite porphyrites, camptonites and tamaraites), and nepheline, analcime and alkaline syenites. Their chemical composition is characterized by a wide range in silica (SiO 2 = 38.7–60.7 wt%), and alkalinity (Na 2 O + K 2 O = 4–18.7 wt%; Na 2 O/K 2 O = 0.5–8.3 wt%), low titanium (TiO 2 = 0.07–2.15 wt%) and high alumina content (Al 2 O 3 = 11.1–28.5 wt%), which corresponds to the K-Na differentiates of the basic alkaline magmatic series. The sum of rare-earth elements (ΣREE) increases from alkaline basite (ΣREE = 103.58–218.94 ppm), to the main foidolites (ΣREE = 137.74–217.61 ppm), and then to the ultrabasic foidolites (ΣREE = 55.56–268.88 ppm). Maximum REE content occurs in nepheline syenites and microsyenites (ΣREE = 73.24–1566.96 ppm) and they are the final product of the differentiation of foidite and basite melts. All dike varieties are characterized by low concentrations of the most highly charged elements (Th, Nb, Ta, Hf, and Y), which, according to their concentrations, plot between oceanic island basalt (OIB) and island arc basalt (IAB). The presence of a negative Nb-Ta anomaly and the relative enrichment of Rb, Ba, Sr and U indicate probable interaction of a mantle plume melts with lithospheric mantle metasomatized in an earlier subduction event. The primary isotope ratio 87 Sr/ 86 Sr(t) = 0.705388–0.706025 and the range of ɛNd(t) from +3.5 to +6.53 in the rocks indicate interaction of mantle derived melts with crustal components. Sm-Nd and U-Pb dating of the alkaline-basite dikes matches the boundary of the Early-Middle Devonian (406–389 Ma) and indicates membership in MTAP-2, which can be linked to the regional ca. 400 Ma Altai-Sayan Large Igneous Province/Rift System. Both the NNW and NNE trending dikes are associated with, and probably fed from, nearby alkaline intrusions such as i.e. Kiya-Shaltyr pluton which are also ca. 400 Ma (part of MTAP-2), but are independent of older ca. 500 Ma intrusions (which belong to MTAP-1) such as the University pluton and which are suggested to belong to a older plume-generated regional event. • Characterization of NNW and NNE trending dike belts in the MTAP, western Siberia. • They formed in the Middle Paleozoic (406–389 Ma) in a plume-rifting event. • Isotopic parameters ɛSr(t) indicate a strong contamination by crustal components. • The dike represent intraplate magmas emplaced in a shear setting.

Long-term survivorship of an exchangeable-neck hip prosthesis with a Ti-alloy/Ti-alloy neck–stem junction

IntroductionBreakage of exchangeable-neck (EN) and adverse local tissue reactions (ALTRs) to neck–stem junction (NSJ) damage products are responsible for increasing the revision rate of EN hip prostheses. We investigated the survivorship of an EN hip prosthesis including a NSJ with both components made of titanium alloy (Ti-alloy/Ti-alloy) to assess whether, and to what extent, EN breakage and NSJ damage affected implant survivorship.Materials and methodsUsing data from a hip replacement registry, we determined survivorship of 2857 EN prostheses. Long-offset configurations of head and EN were implanted in heavy (> 90 kg) patients only in 23 hips. We investigated under which conditions EN breakages or ALTRs occurred. We also measured titanium (Ti) and vanadium (V) blood concentrations in 24 patients with a unilateral well-working prosthesis.ResultsThe 17-year survival rates for any reason and aseptic loosening of any component were 88.9% (95%CI 87.5–90.1; 857 hips at risk) and 96.9% (95%CI 96.0–97.6), respectively. There were two cases of EN breakage and one case of ALTR (metallosis), due to rim-neck impingement, out of 276 revisions. After an average period of 9.8 years (range 7.8–12.8 years), the maximum Ti and V blood concentrations in patients with a well-working prosthesis were 5.0 µg/l and 0.16 µg/l, respectively.ConclusionThe present incidence of EN breakage or ALTR is lower than those reported in other studies evaluating EN hip prosthesis survivorship. This study suggests that (i) the risk of EN breakage is reduced by limiting the use of long-offset configurations in heavy patients and (ii) Ti-alloy/Ti-alloy NSJ damage products do not promote ALTR nor significantly alter the rate of implant loosening. Since design decisions and implant configuration determine the NSJ strength, the NSJ strength in working conditions must be thoroughly investigated to proper define the clinical indications for any EN design.

STRUCTURAL AND LITHOLOGICAL MODEL OF THE ZHEZHELIV DEPOSIT OF ELUVIAL KAOLIN

This study characterizes the geological structure of the Zhezheliv eluvial kaolin deposit, zoning and material composition of the weathering crust, and the mineral composition and physicochemical characteristics of eluvial kaolins. The relationship between rock-forming oxides and the distribution of the contents of Fe2O3, TiO2 and Al2O3 in the vertical section and through the area were investigated. The content of titanium and iron oxides in the kaolin concentrate and its granulometric composition were characterized, depending on the petrotypes of the weathered parent rocks. Maps of the relationship between isolines of the top surface of eluvial kaolins, isolines of their thickness and isolines of the surface of their base have been compiled. A correlation has been established between the topography of the bottom and top and the thickness of the kaolin deposit. A map of the spatial distribution of kaolin whiteness has been compiled. The vertical distribution of whiteness and Fe2O3 and TiO2 contents was investigated for individual wells in the kaolin deposit. It was found that there is no steady correlation between the content of Fe2O3 and TiO2 in the vertical section. The whiteness index of kaolins in the vertical section depends on the content of the indicated oxides or one of them. Based on the analysis of satellite images at different times, the change in the area of the disturbed geological environment during the deposit development through 2006-2020 was assessed.

Electroluminescence from Silicon-Based Light-Emitting Devices with Erbium-Doped ZnO Films: Strong Enhancement Effect of Titanium Codoping.

We report on the visible and near-infrared electroluminescence (EL) from the light-emitting device (LED) based on the erbium (Er)-doped ZnO (ZnO:Er)/SiO2/n+-Si heterostructure, wherein an ∼10 nm thick SiO2 intermediate layer serves as the energy plateau for producing hot electrons, which come from n+-Si via the trap-assisted tunneling mechanism. These hot electrons excite the doped Er3+ ions by inelastic collision, enabling the Er-related EL from the aforementioned LED. More importantly, by means of codoping the appropriate content of titanium (Ti) into the ZnO:Er film, the aforementioned Er-related emissions can be significantly enhanced. The density functional theory calculations indicate that the Ti-codoping improves rather than degrades the symmetry of the crystal field around the optically active Er3+ ions, hence not increasing the intra-4f transition probabilities of Er3+ ions. However, it is found that Ti-codoping nearly eliminates the segregation of Er3+ ions near the ZnO/SiO2 interface. Moreover, Ti-codoping is derived to result in a number of Zn vacancies, which provide the sites for incorporating Er3+ ions in the ZnO matrix. For the above two reasons, the Ti-codoping promotes the incorporation of optically active Er3+ ions into the ZnO matrix, thus enhancing the EL from the aforementioned LED.

Green Synthesis of 2‐Nitropropane via Ammoximation‐Oxidation over Organic Base Modified TS‐1 Catalysts

AbstractModified TS‐1 catalysts for the acetone ammoximation‐oxidation reaction were prepared by post‐treating TS‐1 with different concentrations of TPAOH/TIPA, and the effects of alkali treatment on the catalytic performance were systematically investigated. The techniques such as XRD, SEM, TEM and N2 sorption were used to characterize the catalyst samples, which exhibited that the introduction of alkali increased the volume and quantity of mesopores, while there was no obvious influence on the framework structure and titanium content in the framework. And the improvement in catalyst performance after alkali treatment was attributed to the increase of mesopores and the decrease in diffusion limitation. In addition, three common ammoximation catalysts (Ti‐MOR, Ti‐ MWW and TS‐1) were systematically investigated in this reaction. Ti‐MOR showed superiority in the ammoximation to oxime, while TS‐1 displayed the best catalytic performance in the ammoximation oxidation of ketones to nitroalkanes. It was indicated that modified TS‐1 could be a promising catalyst for the ammoximation‐oxidation reaction of acetone.

Рroperties of wear resistance nickel-free steel with secondary curing for building up stamps of metal hot processing

Problem. The problem, i.e. the reduction of energy and resource consumption during surfacing of a stamping tool can be solved by using dispersion-hardening alloys, limitedly alloyed with chromium (up to 3%), increasing the amount of carbide phase due to the introduction of carbide-forming elements, replacing nickel with manganese, and using surfacing with a de-current additive for their application. The purpose of the work is to increase the wear resistance and heat resistance of secondary hardening surfacing steels by improving the composition of alloying powder wires due to the optimization of the content of titanium, molybdenum and chromium. Methodology. Surfacing was performed with a TS-17M welding tractor under a flux of flux-cored wires with a de-energized additive fed into the main part of the welding bath. Surfacing modes – Iд≈300......320 A; Ud≈34...36 V; Un≈23.7 m/h; Up.e.≈93.75 m/h. The participation rate of the de-energized additive varied within 0...75%. Results. The increase in the content of the [TiC] phase contributed to the increase in the heat resistance of Cr-Mn-Ti alloys based on iron. The introduction of [Mo] stabilized the value of hardness at elevated temperatures, increased heat resistance and hardness during dispersion hardening and additional diffusion formation of the carbide phase during aging. Originality. To increase the alloying of the deposited metal, surfacing with de-current additive was proposed, which allowed to increase the assimilation coefficients of alloying elements. Practical significance. Production tests of stamps welded with these steels made it possible to increase their durability by 1.8 times compared to 5KHNM steel.

Formation of the structure and phase composition of wear-resistant steel alloyed with titanium

Problem. In order to increase the durability of the elements of parts and machines operating in conditions of shock-abrasive and abrasive wear during surfacing, alloys doped with such elements as Cr, W, V, Nb and others have been widely used. Currently, these elements are scarce and expensive in Ukraine. The purpose of the work is to improve the quality and wear resistance of the deposited metal by improving the composition of alloying powders by optimizing the content of titanium and carbon. Methodology. Surfacing was done with a TS-17M tractor and an A-1416 automatic head on plates measuring 200x150x25 mm from 20 steel, 500x300x40 mm from 45 steel, and 400x50x40 from 5KHNM steel. AN-22 flux was adopted as a protective flux for layer-by-layer surfacing of alloyed powder based on CaF2 with Cr-Mn-Ti and Cr-Mn-Mo-Ti alloying systems. Results. It was established that the presence of titanium in the amount of 1.6-2.0% with a carbon content of 0.4-0.5% allows obtaining a carbon-free matrix with a carbide strengthening phase. The hardness of the deposited metal in comparison with the martensitic-troostite structure is slightly reduced by 4...6 HRC. The presence of titanium in the amount of 1.6-2.0% with a carbon content of 0.4-0.5% allows obtaining a carbon-free matrix from the carbide strengthening phase. Originality. A rational method of increasing wear resistance of the deposited metal by multicomponent sparing alloying has been developed, with the help of which it is possible to obtain steels with a strengthening carbide phase and high physical and mechanical characteristics. Practical value. A composition of surfacing steels has been developed for work under conditions of shock-abrasive wear for electric arc surfacing, which contains a Cr-Mn-Ti alloy system based on iron (with a small content of Mo and V) and ensures high quality of the weld metal.

Lithogenic Particle Flux to the Subantarctic Southern Ocean: A Multi‐Tracer Estimate Using Sediment Trap Samples

AbstractMineral dust is a key source of essential micronutrients, particularly iron (Fe), for phytoplankton in the Southern Ocean. However, observations of dust deposition over the Southern Ocean are sparse, hindering assessments of its influence on marine biogeochemistry. We present a time series (2010–2019) of lithogenic particle flux estimates using sediment trap samples collected at 1,000 m depth at the subantarctic Southern Ocean Time Series (SOTS) site. Lithogenic flux was estimated using individual Fe, aluminium (Al), titanium, and thorium concentrations in sediment trap particles less than 1 mm in size. These tracers showed good agreement with one another, and their average was investigated as a proxy for mineral dust deposition. This multi‐tracer average lithogenic flux exhibited strong seasonality, peaking in late spring and summer. No significant Fe enrichment was observed compared to the average upper continental crust, indicating that lithogenic material dominates particulate Fe flux at SOTS. Similar Fe:Al ratios in our samples compared to those reported in marine aerosols off southern Australia, coupled with particle trajectory analysis, suggested Australian dust constitutes the primary lithogenic source to SOTS sinking particles. Lead enrichment in our samples also highlighted an anthropogenic contribution to sinking particles, which might represent an additional aeolian source of more bio‐available Fe to subantarctic waters. This study contributes a new long‐term estimate of lithogenic particle fluxes and aeolian deposition over the subantarctic Southern Ocean. These estimates may enhance model representation of trace metal contribution to biogeochemical processes in the Southern Ocean.

Nanoscale Composite Protective Preparation for Cars Paint and Varnish Coatings

In this work we have developed a nanoscale composite protective preparation for car paint and varnish coatings. We developed methods to obtain SiO2-TiO2, TiO2-ZrO2, SiO2-ZrO2 and SiO2-TiO2-ZrO2 nanocomposites, which are crystallization centers for the formation of a nanoscale composite protective coating with certain morphology and roughness. The phase composition of the samples and stability in alkaline media were studied. It is shown that SiO2-TiO2-ZrO2 nanocomposites with a content of titanium dioxide from 8%–9.5% and zirconium dioxide from 0.5%–2% exhibit complete insolubility in a highly alkaline medium, allow to form uniform structure on paint and varnish coatings, and protect the car surface from exposure to ultraviolet radiation. We determined the optimal composition of the preparation components for the formation of a nanoscale composite protective coating with hydrophobic properties and a wetting contact angle of more than 120 degrees: tetraethoxysilane ≤ 10 vol.%., titanium tetraisopropylate ≥ 2 vol.% and plant resin ≥ 8 vol.% Practical approval of the developed preparation on BMW X6 showed a pronounced hydrophobic effect. Evaluation of the stability of the nanoscale composite protective coating to the washing process showed that the developed preparation is able to maintain its hydrophobic properties for more than 150 washing cycles.

Nanoparticle-induced control (MWCNTs–TiO2) on grain size and tensile strength response and multi-response optimization on TIG welded joints

This study discusses the effectual variable parameters of multi-walled carbon nanotubes and titanium oxide (MWCNT–TiO2) contents and welding current in obtaining a response on mechanical behavior. The experimental work involved three levels of both parameters, which included 1, 1.5, and 2 wt.% of MWCNTs–TiO2 and 160, 180, and 200 A of current by forming a full design that represented a 32 (3 k) factorial model. The results of an analysis of variance (ANOVA) were critically employed to assess the variation between the variables and within their levels for approaching the significant combination of parameters. The joints welded with MWCNT–TiO2-coated fillers tendered a significant reduction in grain size (GS) along with high values of tensile strength (TS). From the ANOVA, it was determined that both the investigated parameters and their combined effect created a significant response for GS reduction and increment in TS. The presented empirical regression quadratic model was validated for the adequacy of the projected results that were shown to be acceptable with the experimental investigated data. In addition, the desirability function approach was applied for a multiple response optimization in yielding the desired responses of GS and TS and simultaneously providing an optimized set of process parameters. Thus, the function declared 1.5 wt.% MWCNT–TiO2 and 180 A as the optimized process set for delivering the maximum TS at the designated range of GS for this system.

Wear resistance performance of high entropy alloy–ceramic coating composites synthesized via a novel combined process

Titanium nitride (TiN), characterized by its high hardness and strength, was widely used as ceramic coating to improve the wear resistance of matrix materials. In this work, AlCrFeNiTix high-entropy alloy (HEA) powders were synthesized by direct electrochemical reduction in molten salt from the mixed metal oxides. Then, TiN ceramic coating on the AlCrFeNiTix bulk HEA containing the topologically close-packed (TCP) phase (σ phase, Laves phase, and Ti3Al phase) was prepared by vacuum hot pressing sintering, where nitride element come from boron nitride parting agent sprayed on the graphite mold. The effect of titanium content on the crystal structure, microstructure, hardness, and wear resistance of the products were investigated by X-ray diffraction, field emission scanning electron microscope, field emission electron-probe microanalysis, Vickers hardness tester, and friction–abrasion testing machine. The bulk HEAs exhibit excellent hardness and its hardness increases significantly with the increase of titanium content. The wear mechanism changes from both of predominantly delamination and accompanied oxidative wear to single delamination wear, which is due to ultra-high melting point and high hot hardness of TiN, that can effectively prevent the oxidation and deformation of the worn surface. Formation of the ceramic coatings containing the TiN second phase and TCP phase are the key factor to AlCrFeNiTix alloy with the excellent hardness and wear properties.

Fe and/or Co-containing coatings on titanium: Features of plasma electrolytic formation, composition, and magnetic properties

Fe- and/or Co-containing coatings have been formed on titanium by plasma electrolytic oxidation (PEO) in electrolytes-sols with colloidal particles of Fe(III) and/or Co(II) compounds. The influence of the electrolyte formula has been studied on the coatings' composition, surface morphology, and magnetic properties. It has been established that the total concentration of iron, cobalt, and titanium in the coating composition is 13.1–22.0 at. %, while their thickness varies from 22 to 37 μm, and the porosity ranges from 10 to 26 %. Micro- and nanosized crystal-like particles have been found both on the surface (in valleys, around pore mouths, and in caps covering pores) and inside pores (at the bottom and walls). In the particles and the layer lining the bottom of the pores, the concentration of iron, cobalt, and titanium is higher than over the surface (49.7–59.1 at. %). Depending on electrolyte formula, the crystallites located in the pores contain (at. %) 28.4–39.3 O; 3.5–9.5 P; 20.3–29.4 Ti; 2.1–7.5 W; up to 22 Fe and up to 38.8 Co. The values of the coercive force measured at 300 K vary from 6366 to 27,056 A/m, and those at 3 K range from 3581 to 17,428 A/m. The ferromagnetic properties of the coated samples correlate with the elemental composition of the particles found in the pores and on the surface.

Relationship between maternal exposure to heavy metal titanium and offspring congenital heart defects in Lanzhou, China: A nested case-control study.

BackgroundPrevious studies have found that exposure to heavy metals increased the incidence of congenital heart defects (CHDs). However, there is a paucity of information about the connection between exposure to titanium and CHDs. This study sought to examine the relationship between prenatal titanium exposure and the risk of CHDs in offspring.MethodsWe looked back on a birth cohort study that was carried out in our hospital between 2010 and 2012. The associations between titanium exposure and the risk of CHDs were analyzed by using logistic regression analysis to investigate titanium concentrations in maternal whole blood and fetal umbilical cord blood.ResultsA total of 97 case groups and 194 control groups were included for a nested case-control study. The [P50 (P25, P75)] of titanium were 371.91 (188.85, 659.15) μg/L and 370.43 (264.86, 459.76) μg/L in serum titanium levels in pregnant women and in umbilical cord serum titanium content in the CHDs group, respectively. There was a moderate positive correlation between the concentration of titanium in pregnant women's blood and that in umbilical cord blood. A higher concentrations of maternal blood titanium level was associated with a greater risk of CHDs (OR 2.706, 95% CI 1.547–4.734), the multiple CHDs (OR 2.382, 95% CI 1.219–4.655), atrial septal defects (OR 2.367, 95% CI 1.215–4.609), and patent ductus arteriosus (OR 2.412, 95% CI 1.336–4.357). Dramatically higher concentrations of umbilical cord blood levels had an increased risk of CHDs and different heart defects.ConclusionTitanium can cross the placental barrier and the occurrence of CHDs may be related to titanium exposure.

Electrochemical Performance of NASICON-structured Na3-x V2-xTix(PO4)3 (0.0 &lt; x &lt; 1.0) as aqueous Na-ion battery positive electrodes

Phosphate frameworks with NASICON structure are among the most studied and applied Li- and Na-ion battery electrode and electrolyte materials. In this work, the NASICON-structured Na3-xV2-xTix(PO4)3 with x = 0.0, 0.25, 0.5, 0.75 and 1.0 are successfully prepared by conventional solid-state synthesis and characterized in detail as potential aqueous Na-ion battery positive electrodes with improved charge capacity and cycling stability. Structural analysis using powder X-ray diffractometry indicates that titanium substitutes vanadium at arbitrary concentration without significant distortion of the NASICON structure. The results show that titanium content in this system directly correlates with its aqueous stability when cycled in simple 1 M Na2SO4 aqueous electrolyte within the vanadium redox potential range. Electrochemical kinetics and charge capacity measurements show Na2VTi(PO4)3 as well as Na2.25V1.25Ti0.75(PO4)3 to be stable positive electrodes in simple aqueous electrolyte solutions. Hybrid density functional theory analysis of V-O chemical bonding suggests that it is stabilized by the presence of titanium in the NASICON structure. In this work, we show that the observed capacity loss in full symmetric cells is caused by the capacity imbalance between positive and negative electrodes which progresses during cycling but not the aqueous materials stability per se. This imbalance is caused by several parasitic reactions, the most important being the oxygen reduction reaction catalyzed by Ti(III) species. Careful mitigation and management of this reaction could, in principle, allow for the preparation of truly capacity balanced cells (i.e. without a need of any electrode overcapacity), and superior cycling stability.

Thicknesses of Mare Basalts in the Chang’E‐5 Landing Region: Implications for the Late‐Stage Volcanism on the Moon

AbstractChina's Chang’E‐5 mission has collected lunar samples from a young mare plain with elevated thorium contents in the northeastern Oceanus Procellarum of the Moon. In this study, we first established a local stratigraphic column of the landing region based on the radial variation of the titanium content in the ejecta of large penetrating craters, and we found that the landing region was flooded by at least four layers of mare basalts. By using the latest imagery, spectral, topographic, and gravity data, we then estimated the basalt thickness of each layer based on the excavation depth of penetrating craters, the morphology of partially buried craters, and the effective density spectrum technique, which can help to better understand the late‐stage volcanism on the Moon. Our results show that the four layers of basaltic lava flows in the landing region have accumulated thicknesses of 9–175, 11–167, 19–478, and 0–800 m. Combined with surface areas and ages of the basaltic units, we then calculated the eruption rate of mare basalts in the landing region, which shows an uptick at about 2 Ga. This result indicates a rejuvenated volcanic activity on the Moon, most likely due to the presence of heat‐producing elements in the KREEP layer. Alternatively, the long‐standing volcanism in this region could be also sustained by extra heating induced by the tidal force and/or a thin crust layer that favors the magma ascent.

Chitosan and Titanium Dioxide Are More Effective in Improving Seed Yield and Quality in Nanoparticle Compared to Non-Structured Form: A Case Study in Five Milk Thistle Ecotypes (Silybum marianum (L.) Gaertn.)

Milk thistle is an important medicinal crop. In this two-year field study, the optimal form [bulk (non-structured), nanoparticles (NPs)] and concentration (0, 50, 100 mg L−1) of chitosan and titanium dioxide (TiO2) applications for improving seed yield, as well as seed mineral (N, Mg, Fe, Ti), protein, and oil contents were investigated in five ecotypes. Leaf gas exchange, ratio of variable to maximum fluorescence (Fv/Fm), and hydration were also evaluated in situ. Chitosan and TiO2 improved all traits under study, with the former generally being more effective. When applied in the NP form, the positive effect was stronger. For chitosan NPs, a low concentration was optimal. Increased hydration status was associated with enhanced stomatal conductance, which, together with Fv/Fm, were positively related to photosynthetic rate. The seed yield per plant was positively related to main capitulum traits (i.e., diameter, number, and weight of seeds), as well as to seed weight and number of capitula per plant. In conclusion, the improvement of seed yield and quality by application of chitosan and TiO2 in either form was underlain by the same components, though their relative importance depends on the ecotype. Chitosan NPs were most effective, demonstrating an economical, eco-friendly, and sustainable means to stimulate milk thistle yield.

Al – Ti – B master alloys: structure formation in modified alloys

This paper provides an overview of existing grain refinement mechanisms and describes the solidification kinetics typical of alloys modified with the Al &ndash; Ti &ndash; B system. Of practical interest are intermetallic compounds of the binary Al &ndash; Ti system, the state diagram of which requires further study. It was found that, with titanium concentrations being low, the behaviour of the system is influenced by peritectic reaction leading to &alpha;-grains of aluminium forming on titanium aluminide particles (TiAl3). A unique feature of the Al &ndash; Ti system is that, compared with other alloys, it has the highest limited growth rate Q, which explains the high grain refinement performance. Microparticles of titanium diboride (TiB2) that form in the liquid state of the Al &ndash; Ti &ndash; B system act as nucleation centres for the intermediate phase of TiAl3. At the same time, TiAl3 was found to display metastable properties and it dissolves as aluminium solidifies. The classical crystallization theory defines the importance of heterogeneous substrates that help grain nucleation by lowering the threshold energy. According to the heterogeneous nucleation theory, supercooling tends to increase dramatically during grain nucleation as the discrepancy rises between the crystal lattice of the solid body and that of the substrate. In terms of constitutional supercooling, it takes lower supercooling for grain nucleation on a particle. The contributing factors include a lower rate of latent heat release and low grain growth rates. As the master alloy was introduced in the melt, the authors observed reduced modification efficiency (with the concentration &gt;1.5 %) and dropped solubility of Ti in the presence of Si. Long soaking times would lead to the master alloy gradually lose its effect. The authors also considered how the properties of master alloys can be enhanced. Thus, they looked at breaking up TiAl3 by means of plastic deformation and deagglomerating TiB2 particles by contactless mixing.