Vanadium Samples Research Articles

Association of exposure to environmental vanadium and manganese with lung function among young children: A population-based study

Exposure to environmental metals has been associated with health outcomes including respiratory health. Little is known about the impact of exposure to environmental metals on lung function among young children in general population. This study aimed to investigate the associations of exposure to metals with lung function among young children in a population-based cohort. A total of 1488 children aged 5–8 years attended a follow-up visit as part of the Longitudinal Investigation of Global Health in Taiwanese Schoolchildren (LIGHTS) cohort. We measured urinary samples of vanadium (median: 1.21 ng/mL; interquartile range (IQR): 0.73–1.98), manganese (median: 0.23 ng/mL; IQR: 0.13–0.47), arsenic (median: 40.51 ng/mL; IQR: 21.66–70.49), nickel (median: 1.09 ng/mL; IQR: 0.31–3.60), and cadmium (median: 0.26 ng/mL; IQR: 0.11–0.43) and performed lung function tests. Urinary vanadium concentrations were inversely associated with FVC (β coefficient for the highest quartile versus the other quartiles: −33.40, p = 0.001), FEV1 (β: −41.31, p < 0.001), FEV1/FVC ratio (β: −1.00, p = 0.009), PEF (β: −92.12, p = 0.004), and FEF25–75 (β: −82.85, p < 0.001), after adjusting for relevant confounders. Urinary manganese concentrations were inversely associated with FVC (β: −26.60, p = 0.007), FEV1 (β: −31.62, p = 0.001), PEF (β: −84.86, p = 0.009), and FEF25–75 (β: −69.21, p = 0.002). Stratification analyses found inverse associations of urinary vanadium and manganese concentrations with lung function parameters predominantly among children exposed to environmental tobacco smoke. We did not find significant associations of urinary arsenic, nickel, and cadmium concentrations with lung function parameters. In conclusion, this study adds new evidence showing inverse associations of vanadium and manganese exposure with lung function among young children in the general population. Children with environmental tobacco smoke exposure are particularly vulnerable to adverse impact of vanadium and manganese exposure on lung function.

Positron Annihilation and EBSD Studies of Subsurface Zone Created During Friction in Vanadium

Abstract Positron lifetime and electron backscatter diffraction studies were performed on pure vanadium samples subjected to the sliding test. The changes in the microstructure produced in this test are extending even to a depth of about 450 µm. As shown by the diffraction of electron backscattering, near this surface, just after starting the sliding test, a tribolayer with refinement randomly oriented grains is formed. The thickness of this layer varies from 8 µm to 19 µm depending on the sliding conditions and the mean grain size is about 0.2 µm. Its source is believed to be a continuous process of dynamic recrystallization. In this layer, the formation of cracks and debris is observed as well. Below is an intermediate layer with elongated grains and serrated grain boundaries in which a geometric dynamic recrystallization process has been recognized as well.

EXPERIMENTAL STUDIES ON HIGH-TEMPERATURE CORROSION INTERACTION OF TIN-LITHIUM ALLOY WITH STAINLESS STEEL AND REFRACTORY METALS

This article describes experimental investigations to determine the corrosion compatibility of candidate matrix materials of a capillary-porous structure (CPS) with a liquid tin-lithium alloy at high temperatures. The studies were conducted with the Sn75-Li25 alloy and samples of 12Ch18Ni10Ti grade austenite stainless steel, VEL-3 grade vanadium, and TT grade tantalum. Experiments on the interaction of a liquid tin-lithium alloy with candidate samples of the CPS matrix at high temperatures were carried out on an experimental TiGrA setup based on a TGA/DSC 3+ thermogravimetric analyzer. The paper provides a description of the methodology and conditions for conducting high-temperature corrosion tests. In the course of this work, experiments were carried out to study the compatibility of a tin-lithium alloy in the liquid phase with a stainless steel, vanadium and tantalum samples in the temperature range from 600 ℃ to 1000 ℃. Based on obtained results, the thermal effects of the processes occurring as a result of the interaction of the alloy with a candidate materials of the CPS matrix were determined. As a result of the analysis of the results obtained it has been revealed that at interaction of the studied materials with liquid tin-lithium alloy Sn75-Li25 at high temperatures complex physical and chemical processes take place, such as: selective dissolution of components by liquid alloy (solvent); penetration of component of liquid alloy (tin) into stainless steel depth; mass transfer of dissolved metals from solid metal into liquid.

Post irradiated microstructure and mechanical properties of pure V

Proton irradiation has been carried out on pure vanadium samples and the changes in the microstructure and mechanical properties have been evaluated as a function of dose. The microstructural parameters such as domain size and microstrain have been assessed along different crystallographic planes using the X-ray diffraction line profile analysis methods such as simplified breadth and the modified Rietveld technique. No significant change in the dislocation density is observed as a function of dose from the XRD results. However, the results of positron annihilation spectroscopy in terms of positron lifetime and S-parameter clearly indicated the formation of small defect clusters with irradiation. Transmission electron microscopy investigation confirmed the presence of small dislocation loops in the irradiated samples. Molecular dynamics simulations carried out to model the formation of irradiation-induced defects clusters with irradiation dose support the experimental observation of small defect clusters and increasing cluster size with dose. The yield strength and tensile strength showed systematic increase with irradiation dose corroborating with the results of microhardness measurement. The fractography of the tensile samples clearly showed the characteristics of brittle fracture in the irradiated samples.

Study of liquid tin-lithium alloy interaction with structural materials of fusion reactor at high temperatures

The paper presents the experimental studies to determine the corrosion compatibility of various base materials of the capillary-porous structures (CPS) with a liquid tin-lithium alloy under high temperatures. The experiments were carried out with Li-Sn alloy and the samples of vanadium, tungsten, molybdenum, tantalum, and stainless steel. These materials were selected as the candidate ones for the matrix of Li-Sn CPS prototypes. Manufacture of Li-Sn alloy and experiments were carried out at test bench VIKA. The ranges of the temperatures was: 600 °C–800 °C for stainless steel, and 850 °C–1000 °C for other metals; exposure time for every temperature step was up to 100 h.The implemented activities included manufacture of Sn-Li alloys with various lithium contents (25 at.% and 27 at.%), characterization of the samples, experiments to study compatibility of liquid tin-lithium with vanadium, tungsten, molybdenum, tantalum at temperatures of 850 °C–1000 °C, and stainless steel at temperatures of 600–800 °C. As a result of the performed activities, molybdenum and tungsten were selected as the most corrosion resistant materials in respect to Li-Sn alloys.

Spectral emissivity, hemispherical total emissivity, and constant pressure heat capacity of liquid vanadium measured by an electrostatic levitator

Vanadium samples were levitated in an electrostatic levitator and their radiation intensities at their melting temperature were measured by spectrometers over a wide wavelength range. By comparing the measured intensities with those of a blackbody, spectral hemispherical emissivity values were calculated. The total hemispherical emissivity of vanadium at its melting temperature was calculated by integrating the spectral hemispherical emissivity and was found to be 0.32. The constant pressure heat capacity was also calculated using time–temperature data and was found to be 48.5 J·mol−1·K−1 at 2200 K.

Shock-induced twinning in polycrystalline vanadium: I. twinning stress

The shock-induced twinning at room temperature was studied using 3 mm thick vanadium samples of commercial purity (99.8 wt%), softly recovered after planar impact loading by copper impactors with velocities ranging from 262 to 610 m/s. Microscopic (Light and Scanning Electron) examinations of the samples' cross-sections revealed twins in a strip of vanadium grains, located 100–900 μm apart from the impacted sample surface. Transmission electron microscopy characterization allowed concluding that these twins are produced by a/6 〈111〉{211} glide in subsequent {211} planes. The number of twins, Ntw, per unit area varied from its maximum value, measured at the distance h = 0.2–0.3 mm from the impacted sample surface, to Ntw = 0 at h = 0.7–0.9 mm apart from the surface. Juxtaposition of the presently obtained Ntw(h) dependencies with previously reported spatial distribution of the shear stress, τ(h), in shock-loaded vanadium samples made it possible to determine twinning stress in vanadium as: τ (Ntw = 0) = τtw = 0.68(±0.03) GPa.

Shock-induced twinning in polycrystalline vanadium: II. Surface layer

In the course of study of shock-induced twinning in commercially pure (99.8 wt%) polycrystalline vanadium, some unexpected metallurgical features were found. In all vanadium samples softly recovered after planar impact loading by copper impactors with velocities ranging from 262 to 610 m/s, the domain of twinned grains (located at the distance 100–900 μm from an impacted sample surface) preceded by a relatively narrow strip, 60–100 μm, densely filled by martensite lenticles of micron size. The distribution of shock-induced twins and the stress, required for their nucleation, were considered in the Part I of the present paper series. Part II of this series is focused on the Transmission Electron Microscopy study of the lenticles, formed in immediate proximity to the impacted surface. It was found that these lenticular particles are oblate ellipsoids of micron size filled with the stacks of 10–30 nm thick planar slabs, which possess tetragonal crystal structure. The slabs have alternating orientation of tetragonal axes c while the parameters of their unit cell are derivatives of cubic lattice parameter of vanadium, aV, namely a = b = 2aV and c = aV. Possible model, based on a sequence of glides, capable to generate such microstructure, and the cause for the disappearance of the lenticles beyond 100 μm apart from the impacted surface are discussed.

Total neutron scattering and data analysis in a virtual experiment: a case study on heavy water with a vanadium calibration sample

A total scattering neutron instrument is simulated using a ray-tracing package to evaluate the technique and data reduction algorithms. The neutron guide and chopper system were first optimized to obtain the highest neutron flux with satisfactory angular divergence. Next, a series of virtual experiments were conducted using heavy water and calibration vanadium samples. Data analysis algorithms were also developed. The resultant simulated sample static structure factor was in excellent agreement with the experimental measurements. Additionally, analytical and Monte Carlo methods are applied to account for multiple scattering in a variety of sample sizes. The effectiveness of this method and possible improvements are discussed.

A simulational study of the indirect-geometry neutron spectrometer BIFROST at the European Spallation Source, from neutron source position to detector position.

The European Spallation Source (ESS) is intended to become the most powerful spallation neutron source in the world and the flagship of neutron science in upcoming decades. The exceptionally high neutron flux will provide unique opportunities for scientific experiments but also set high requirements for the detectors. One of the most challenging aspects is the rate capability and in particular the peak instantaneous rate capability, i.e. the number of neutrons hitting the detector per channel or cm2 at the peak of the neutron pulse. The primary purpose of this paper is to estimate the incident rates that are anticipated for the BIFROST instrument planned for ESS, and also to demonstrate the use of powerful simulation tools for the correct interpretation of neutron transport in crystalline materials. A full simulation model of the instrument from source to detector position, implemented with the use of multiple simulation software packages, is presented. For a single detector tube, instantaneous incident rates with a maximum of 1.7 GHz for a Bragg peak from a single crystal and 0.3 MHz for a vanadium sample are found. This paper also includes the first application of a new pyrolytic graphite model and a comparison of different simulation tools to highlight their strengths and weaknesses.

Особенности разрушения металлов при импульсном лазерном и пучково-плазменном воздействии

The features of the destructive effect of high-pressure generated under comparable conditions, namely, upon irradiation of target samples with pulsed laser radiation and beam-plasma flows created in Plasma Focus (PF) devices, on metal materials were studied. In both cases, close parameters of radiation-heat treatment were provided: power density q ~ 1010–1011 W/cm2 and pulse duration τ ~ 10 –100 ns. It have been shown that the double exposure of laser radiation to thin samples of vanadium and molybdenum with a thickness of 0.3 mm and 0.1 mm, respectively, leads to the formation of molten zones in the materials, inside which there were deep craters. The craters extended over the entire thickness of the samples, on the reverse side of which the recesses end with holes of ~ 0.1 mm for V and 0.2 mm for Mo. In a tungsten sample 0.2 mm thick, the depth of the craters in the molten zone was less than its thickness and there were microcracks on the back of the sample. Based on numerical estimates of the process under study, it was suggested that the observed effects are associated with the creation of high pressure zones of ~ 1 – 10 GPa in the irradiated targets, localized in microregions of radius r ~ 0.1 mm. In these zones, the behavior of the solid phase of the target materials, for which the tensile strength σB ≤ 1 GPa (V, Mo, W), under high pressure became close to the behavior of the liquid. The pseudo-liquid phase of the material was displaced from the center of the crater, where the pressure was maximum, to its periphery to the region of low pressure with the subsequent release of matter from the target through the irradiated surface at a speed of ~ 103 m/s. In experiments using the PF, the mechanism responsible for the formation of craters when a powerful pulsed laser radiation is applied to the target is not realized due to the different nature of the distribution of the absorbed energy density in the surface layer of the irradiated sample. The region in which the energy absorbed during the of particles implantation into the material was determined mainly by the average energy and the diameter of the ion beam (Еi ≈ 100 keV, d ~ 2 – 10 mm) and exceeds by one or two orders of magnitude the corresponding volume under laser irradiation.

Structural Transformations in the Grain Boundary Region of Nanocrystalline Metals Under Mechanical Loading

Molecular dynamics analysis of special features of structural transformations at the grain boundaries (GBs) of nanocrystalline metals with face-centered cubic (FCC) and body-centered cubic (BCC) lattices under shear loads is performed. The objects of the study are nickel and vanadium samples containing symmetric tilt GBs. Shear loading is specified by the displacement of the surface atomic layers parallel to the GB plane at a constant speed. Shear load causes a high-speed GB movement along the normal to the boundary plane. To initiate the GB movement, high stress is required. Periodic boundary conditions prevent the occurrence of the grain rotations. The GB velocity is determined by the shear rate and depends on the grain misorientation angle. It has been found that the GB movement has a jump-like nature and is accompanied by a rapid drop in the internal stresses. Self-consistent structural transformations of atomic planes, through which the high-speed GB movement in a metal occurs, are revealed.

Influence of a 6-month physical training program on serum and urinary concentrations of trace metals in middle distance elite runners

BackgroundThe aim of this survey was to determine the effects of an aerobic physical training program of six months duration on the serum and urinary concentrations of essential trace elements among middle distance runners and untrained, non-sportsmen participants.Methods24 well-trained, middle-distance (1500 and 5000 m), aerobic male runners (AG) were recruited at the beginning of their training season and 26 untrained males formed the control group (CG). All participants were from the same region of Spain, and all of them had been living in this area for at least two years. Serum and urine of samples of Cobalt (Co), Copper (Cu), Manganese (Mn), Molybdenum (Mo), Selenium (Se), Vanadium (V) and Zinc (Zn) were obtained at the beginning of the training season, and six months later, from all participants. All samples were analyzed with inductively coupled plasma mass spectrometry (ICP-MS).ResultsTwo-way ANOVA showed significant differences relative to group effect in serum concentrations of Co, Cu, Mn, Mo, Se and Zn. Attending to time effect, there were differences in Mn (p = 0.003) and Zn (p = 0.001). The group x time interaction revealed differences only in the case of Mn (p = 0.04). In urine, significant differences between group were obtained in Co, Cu, Mn, Se and V. Time effect showed changes in Co, Cy, Mo and Se. Finally, the group and time interaction revealed significant differences in urinary Cu (p = 0.001), Mn (p = 0.01) and Se (p = 0.001).ConclusionsA six-month aerobic training program for well-trained athletes induced modifications in the body values of several minerals, a fact which may reflect adaptive responses to physical exercise. The obtained data could be interesting for physicians or coaches in order to consider specific modifications in sportsmen’s diets as well as to determine specific nutritional supplementation strategies.

Synthesis and Properties of Vanadium Substituted Bismuth Tungstates with Fluorite-like Structure

The samples of vanadium substituted bismuth tungstates with a cubic structure were obtained by solid state method. The unit cell volume of the compounds slightly contracts with increasing tungsten content and in case of vanadium doping. Thermal expansion coefficient of bismuth tungstate is equal to 13×10-6 °C-1. The electrical conductivity was investigated using ac impedance spectroscopy. The results showed that the substitution of tungsten with vanadium ions increased electrical conductivity values by one order of magnitude.

Ice Ih revisited: No proton tunneling observed in a quasielastic neutron scattering experiment

A large broadening ($\ensuremath{\sim}0.4\phantom{\rule{0.16em}{0ex}}\mathrm{meV}$) of quasielastic neutron scattering (QENS) signal in ${\mathrm{H}}_{2}\mathrm{O}$ ice ${I}_{h}$ at $T=5\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ was observed by Bove et al. [Phys. Rev. Lett. 103, 165901 (2009)] and explained by a model of concerted proton tunneling. This result was rather unexpected, as prior studies never showed significant mobility in water at low temperatures and ambient pressure. There were a few attempts of theoretical understanding of the effect. Recent path-integral simulations as well as quantum lattice-gauge theory supported the possibility of the collective tunneling of protons in ice ${I}_{h}$, however other studies stated that concerted tunneling in ice ${I}_{h}$ should have very low frequency. Here, we report on QENS measurements of ${\mathrm{H}}_{2}\mathrm{O}$ ice ${I}_{h}$ at 1.8 and 5 K by using neutron scattering spectrometers with the energy resolution similar to and four times better than the energy resolution in the original experiment of Bove and co-workers. We did not observe any QENS broadening, and the measured spectra for the ice ${I}_{h}$ and the reference vanadium sample were almost identical. Therefore, we conclude that there is no proton tunneling in ice ${I}_{h}$ at temperatures down to 1.8 K measurable on an energy scale of 3.5 $\ensuremath{\mu}\mathrm{eV}$ and above. The literature data on low-temperature heat capacity of ice ${I}_{h}$ support this conclusion.

Interstitial-atom-induced phase transformation upon hydrogenation in vanadium

The effect of interstitial atoms (nitrogen, carbon) on hydrogen storage properties in vanadium was investigated. When the N concentration was below 0.4 wt%, the plateau pressures increased with increasing N concentration during absorption and desorption and vanadium samples (body-centered cubic (BCC)) transformed to VH0.5 (body-centered tetragonal (BCT), c/a = 1.1) and then VH2 (face-centered cubic (FCC)). When the N concentration exceeded 0.6 wt%, a new single-phase region appeared in the pressure-composition isotherm, suggesting the formation of a new hydride phase. The X-ray diffraction data indicated that this new hydride phase was VH1.0 with a BCT structure and c/a = 1.24, and the phase transformation took place as V (BCC) became VH0.5 (BCT, c/a = 1.1), followed by VH1.0 (BCT, c/a = 1.24) and then VH2 (FCC). Density functional theory calculations indicated that the BCT structure model with hydrogen atoms fully occupying the octahedral sites (denoted as the Oz site) can explain the experimentally obtained crystal structure for VH1.0; they also indicated that the VH1.0 phase was stabilized by the addition of nitrogen. In addition, the N occupation site changed from the Oz site in VH0.5 and VH1.0 to the tetrahedral site (denoted as the T site) in VH2 in coordination with hydrogen during hydrogen absorption. A similar phenomenon was observed in carbon-containing vanadium. It can thus be concluded that the phase transformation pathway and stability of the hydride phases in the V–H system are highly sensitive to the addition of interstitial C and N atoms.

Effect of Pulsed Nitrogen Plasma and Nitrogen Ion Fluxes on the Structure and Mechanical Properties of Vanadium

The effect of powerful pulsed fluxes of nitrogen plasma and nitrogen ions generated in the PF-4 Plasma Focus setup (LPI; energy flux density of plasma pulse was 108–1010 W/cm2) on the modification of vanadium surface is studied. Melting and ultrafast solidification result in a fine cellular structure (cell size of 100–200 nm) in a thin surface layer in samples. There are irradiation regimes causing directional crack growth after solidification and cooling of the surface layer and the formation of a block microstructure with a block size of several tens of micrometers. The thickness of the melted layer in the samples is 2–4 μm. Cracks propagate to a depth of 5–20 μm. It is established that irradiation by pulsed nitrogen plasma and high-energy nitrogen ions changes the microhardness of the vanadium surface layers. The microhardness increases by a factor of three with the number of plasma pulses and the distance between a sample and the anode of the Plasma Focus (PF) setup. The increase in the microhardness is in agreement with the refinement of coherent scattering regions, the increase in lattice microstrain e, and the formation of vanadium nitrides. Pulsed fluxes of nitrogen plasma and nitrogen ions decrease the lattice parameter much greater than cold working (rolling) does. The lattice parameter decreases when the total irradiation power is increased (the number of pulses increases or the distance between a sample and the anode of the PF setup decreases). Such changes seem to be caused by the action of the residual macrostresses induced by pulsed plasma irradiation. In addition, X-ray diffraction analysis showed a change in the texture of the surface layer after ion-plasma treatment of coldworked vanadium samples in the PF setup.

Structural phase transition, strength, and texture in vanadium at high pressure under nonhydrostatic compression**Project supported by the National Natural Science Foundation of China (Grant Nos. 10875142 and 11079040) the Project of Sichuan University of Arts and Science, China (Grant No. 2017KZ001Z), and the Program of Education Department of Sichuan Province, China (Grant No. 18ZB0506). This work was performed at 4W2

The structural phase transition, strength, and texture of vanadium have been studied under nonhydrostatic compression up to 70 GPa using an angle-dispersive radial x-ray diffraction technique in a 2-fold paranomic diamond anvil cell and up to 38 GPa using an angle-dispersive x-ray diffraction technique in a modified Mao–Bell diamond anvil cell at room temperature. We have confirmed a phase transition from body-centered cubic structure to rhombohedral structure at 27–32 GPa under nonhydrostatic compression. The radial x-ray diffraction data yields a bulk modulus GPa and its pressure derivative for the bcc phase and with for the rhombohedral phase at ψ = 54.7°. The nonhydrostatic x-ray diffraction data of both bcc and rhombohedral phases yields a bulk modulus with . Combined with the independent constraints on the high-pressure shear modulus, it is found that the vanadium sample can support a differential stress of ∼1.6 GPa when it starts to yield with plastic deformation at ∼36 GPa. A maximum differential stress as high as ∼1.7 GPa can be supported by vanadium at the pressure of ∼47 GPa. In addition, we have investigated the texture up to 70 GPa using the software package MAUD. It is convinced that the body-centered cubic to rhombohedral phase transition and plastic deformation due to stress under high pressures are responsible for the development of texture.

Structural Changes in the Vanadium Sample Surface Induced by Pulsed High-Temperature Deuterium Plasma and Deuterium Ion Fluxes

The structural changes in the vanadium sample surface are studied as functions of the conditions of irradiation by pulsed high-temperature deuterium plasma and deuterium ion fluxes in the Plasma Focus installation. It is found that processes of partial evaporation, melting, and crystallization of the surface layer of vanadium samples take place in the plasma flux power density range q = 108–1010 W/cm2 and the ion flux density range q = 1010–1012 W/cm2. The surface relief is wavelike. There are microcracks, gas-filled bubbles (blisters), and traces of fracture on the surface. The blisters are failed in the solid state. The character of blister fracture is similar to that observed during usual ion irradiation in accelerators. The samples irradiated at relatively low power density (q = 107–108 W/cm2) demonstrate the ejection of microparticles (surface fragments) on the side facing plasma. This process is assumed to be due to the fact that the unloading wave formed in the sample–target volume reaches its irradiated surface. Under certain irradiation conditions (sample–anode distance, the number of plasma pulses), a block microstructure with block sizes of several tens of microns forms on the sample surfaces. This structure is likely to form via directional crack propagation upon cooling of a thin melted surface layer.

X-ray diffraction measurements of plasticity in shock-compressed vanadium in the region of 10–70 GPa

We report experiments in which powder-diffraction data were recorded from polycrystalline vanadium foils, shock-compressed to pressures in the range of 10–70 GPa. Anisotropic strain in the compressed material is inferred from the asymmetry of Debye-Scherrer diffraction images and used to infer residual strain and yield strength (residual von Mises stress) of the vanadium sample material. We find residual anisotropic strain corresponding to yield strength in the range of 1.2 GPa–1.8 GPa for shock pressures below 30 GPa, but significantly less anisotropy of strain in the range of shock pressures above this. This is in contrast to our simulations of the experimental data using a multi-scale crystal plasticity strength model, where a significant yield strength persists up to the highest pressures we access in the experiment. Possible mechanisms that could contribute to the dynamic response of vanadium that we observe for shock pressures ≥30 GPa are discussed.