Small Amount Of Pb Research Articles

Multifunctional Acetaminophen Interlayer for High Efficiency and Durability Lead-Lean Perovskite Solar Cells.

Due to the easy oxidation of Sn2+, which leads to form tin vacancy defects and poor perovskite film quality, caused by the rapid crystallization rate in tin-based perovskite solar cells (PSCs), their efficiency lags far behind that of lead-based PSCs. To improve the photovoltaic (PV) performance and stability of FA0.9PEA0.1SnI3-based PSCs (T-PSCs), a small amount of Pb(SCN)2 is introduced into a perovskite precursor as an antioxidant, and acetaminophen (ACE) with various functional groups is used to modify a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/perovskite interface. The results show that the Pb(SCN)2 additive and ACE interfacial modification can not only optimize energy level alignment in T-PSCs but also inhibit Sn2+ oxidation to reduce the trap-state density, resulting in promoted carrier transport. The synergetic effect of the Pb(SCN)2 antioxidant and ACE interfacial modification significantly reduces nonradiative recombination and improves the PV performance and stability of T-PSCs. Consequently, the unsealed T-PSCs with the Pb(SCN)2 additive and ACE modification achieve a champion efficiency of 12.04% and maintain 99% of their initial PCE after being stored in N2 for more than 2100 h, while reference T-PSCs demonstrate a champion PCE of 6.20% and retain only 72% of its initial PCE. Moreover, the modified T-PSCs without encapsulation demonstrate much better stability in humid air.

ANALISA KADAR TIMBAL DALAM DARAH TUKANG BECAK DI WILAYAH SURABAYA UTARA

Lead (Pb) is one of the heavy metals with high toxicity which can pollute an environment and affect survival. Lead that enters the body is excreted into the bones, teeth and hair. A small amount of Pb, stored in the brain. 99% of lead binds to erythrocytes. The purpose of this study was to analyze the levels of lead (Pb) in the blood of pedicab drivers at Jembatan Merah, North Surabaya. This type of research is a type of descriptive research conducted at the Toxicology Laboratory, Campus of Technology, Medical Laboratory of the Surabaya Polytechnic, Surabaya Center for Standardization and Industrial Services from October 2022 to May 2023. The research sample was 20 venous blood of pedicab drivers at the Red Bridge in North Surabaya with the following criteria: has an age of more than 30 years and has a service life of more than 2 years and then tested using the Atomic Absorption Spectrophotometry (AAS) method. The results of the 20 samples showed that blood lead levels in pedicab drivers in the North Surabaya Region were still within the normal threshold set by WHO in 2021, namely <5 µg/dl or 0.05 mg/L.

Cometal Addition Effect on Superconducting Properties and Granular Behaviours of Polycrystalline FeSe0.5Te0.5.

The enhanced performance of superconducting FeSe0.5Te0.5 materials with added micro-sized Pb and Sn particles is presented. A series of Pb- and Sn-added FeSe0.5Te0.5 (FeSe0.5Te0.5 + xPb + ySn; x = y = 0-0.1) bulks are fabricated by the solid-state reaction method and characterized through various measurements. A very small amount of Sn and Pb additions (x = y ≤ 0.02) enhance the transition temperature (Tconset) of pure FeSe0.5Te0.5 by ~1 K, sharpening the superconducting transition and improving the metallic nature in the normal state, whereas larger metal additions (x = y ≥ 0.03) reduce Tconset by broadening the superconducting transition. Microstructural analysis and transport studies suggest that at x = y > 0.02, Pb and Sn additions enhance the impurity phases, reduce the coupling between grains, and suppress the superconducting percolation, leading to a broad transition. FeSe0.5Te0.5 samples with 2 wt% of cometal additions show the best performance with their critical current density, Jc, and the pinning force, Fp, which might be attributable to providing effective flux pinning centres. Our study shows that the inclusion of a relatively small amount of Pb and Sn (x = y ≤ 0.02) works effectively for the enhancement of superconducting properties with an improvement of intergrain connections as well as better phase uniformity.

The Impact of Soil-Applied Biochars From Different Vegetal Feedstocks on Durum Wheat Plant Performance and Rhizospheric Bacterial Microbiota in Low Metal-Contaminated Soil.

Biochar shapes the soil environment and plant growth. Nevertheless, the mechanisms associated with an improved plant biomass and soil microbiome in low metal-contaminated soils are still unclear. In this study, the influence of biochar on soil physico-chemical properties, plant performance, and rhizosphere microbiota in durum wheat was investigated at the above- and belowground levels. Two kinds of biochar from different feedstocks (wood chips and wheat straw pellets) and two Italian durum wheat varieties, Duilio and Marco Aurelio, were analyzed in a greenhouse using a low-nutrient gleyic fluvisol containing a very small amount of Pb and Zn. Four different treatments were performed: soil-only control (C), soil amended with woody biochar equilibrated with nutrient solution (B1+) and non-activated (B1−), and soil amended with non-activated (B2−) wheat straw biochar. Seven weeks after seed germination, (1) the physico-chemical properties of soil, biochars, and mixtures were assessed; (2) the fresh and dry weight of aboveground plant tissues and roots and other morphometric traits were measured; and (3) metabarcoding of the 16S rRNA bacterial gene was performed on rhizosphere soil samples. The results showed that the biochar from wheat straw had stronger impact on both durum varieties, with higher electrical conductivity, higher levels of available K and Na, and a substantial increase of dissolved Na+, K+, and Cl− ions in pore water. Generally, biochar amendment decreased Zn availability for the plants. In addition, biochar improved plant growth in the early growth stage, and the more positive effect was achieved by combining wheat straw biochar with Marco Aurelio. Rhizosphere bacterial microbiota showed variation in alpha diversity only due to treatment; on the other hand, the differential analysis showed consistent variation among samples with significant effects on amplicon sequence variant (ASV) abundance due to the specific biochar treatment as well as the genotype. The pure B1−, due to its scarce nutrient content with respect to the richer types (B1+ and B2−), had a negative impact on microbiota richness. Our study highlights that an appropriate combination of biochar feedstock and crop species may lead to superior yield.

Effects of Pb addition on microstructures and elemental distribution of AS-CAST AZ61 Mg alloy

AZ61 Mg alloy contains Al and Zn, and it has a good combination of castability, strength and ductility. However, the effect of other alloying elements on AZ61 is seldom investigated. Lead is a cheap metallic material, though its vapor is hazardous, a small amount of Pb as an alloying addition will not have significant influence on the application of Mg alloys. Studies showed that the Pb addition suppresses the formation and growth of discontinuous precipitation in AZ91 alloy. In our study, a small amount of Pb element was added into the AZ61 alloy. Mechanical properties of the alloy have been improved. The microstructures were examined by the optical microscopy (OP), scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS). The elemental distribution with Pb alloying was explicitly studied. This alloy composed of [Formula: see text]-Mg phase and [Formula: see text]-Mg[Formula: see text]Al[Formula: see text] phase, while Pb element inclined to distribute in [Formula: see text]-Mg rather than in [Formula: see text]-Mg[Formula: see text]Al[Formula: see text] phase.

Nano-Channels Early Formation Investigation on Stainless Steel 316Ti after Immersion in Molten Pb-Bi

Development of fuel cladding and structural materials in Pb-Bi environment, especially at high temperature, is a critical issue for the deployment of LFR (Lead alloy-cooled Fast Reactor) and ADS (Accelerator Driven Transmutation System). This is because of the corrosive characteristic of Pb-Bi to metals as constituent materials of fuel cladding and structural of the reactors. Corrosion test of a high-chromium austenitic stainless steel i.e. SS316Ti in molten Pb-Bi at 550 oC has been carried out for about 300 hours continuously. The characterization using SEM-EDS (Scanning Electron Microscopy - Energy Dispersive X-ray Spectroscopy) showed that an iron oxide as the outer layer and a chromium oxide as the inner layer on the surface of the specimen were formed which in general have protected the steel specimen from corrosion and dissolution attack of Pb-Bi. However, small amount of Pb could penetrate into the iron oxide layer through ultra-narrow channels. Atomic Force Microscopy (AFM) with Electrostatic Force Microscopy (EFM) mode was employed to investigate the phenomena of the nano-channels early formation. The results of the nano-scale investigation showed clearly the formation of the channels at the early time of corrosion as the way of Pb to penetrate into iron oxide outer layer.

Phytoextraction of cadmium and lead by three vegetable-crop plants

Phytoextraction, is an effective and promising means to cure soil contamination with heavy metals. The present study investigates the ability of three vegetables plants for removal of heavy metals from the contaminated soil and metal mobilization to different plant parts. The three plants selected for the study, Momordica charantia, Vigna unguiculata and Solanum melongena were grown for 90 days in soils artificially contaminated with cadmium (Cd) and lead (Pb) (50mg metal/kg of soil). The concentrations of the two metals were observed to be higher in roots of M. charantia and V. unguiculata than in soil, but root Pb level of S. melongena was slightly lower than that of soil after 90 days. Translocation potential of the heavy metals indicated higher accumulation of Cd in roots of M. charantia and S. melongena than in leaves while the pattern was completely opposite in V. unguiculata. Lead accumulation was higher in roots than in leaves for all the three plant species studied. The Translocation Factor (TF) of Cd for the three plants was in the range of 1.16 to 2.29 whereas, TF values of Pb remained <1, indicating that only small amount of Pb was translocated from roots to aerial parts.

Electronic and Thermoelectric Properties of Layered Sn- and Pb-Doped Ge2Sb2Te5 Alloys Using First Principle Calculations

A computational study on stable hexagonal phase of undoped, and Sn- and Pb-doped Ge2Sb2Te5 (GST) phase change materials has been carried out. The electronic structure, lattice dynamics and thermoelectric properties of doped GST have been extensively investigated using ab initio methods with virtual crystal approximation. The hexagonal symmetry of the GST is maintained with the addition of Sn and Pb dopants. The lattice parameters and atomic volume of the Sn-doped GST structure is larger than that of the undoped GST. Electronic band structure calculations show that there is an increase in band gap with the increase in the concentration of Sn (≤4.4 at.%). However, with the addition of a very small amount of Pb, there is a continuous decrease in lattice parameters and band gap values. The calculated energy band structure is then used in combination with the Boltzmann transport equation to calculate the thermoelectric parameters of GST and Sn- and Pb-doped materials. Seebeck coefficient (S), electronic thermal conductivity (κe) and the thermoelectric figure-of-merit (ZT) have been calculated with the help of BoltzTraP code. It was found that the thermoelectric properties of GST are enhanced with the addition of Sn.

Lead citrate precursor route to synthesize nanostructural lead oxide from spent lead acid battery paste

Nanostructural lead oxides were prepared by the decomposition of a new type of lead citrate precursor (Pb3(C6H5O7)2·3H2O), which was synthesized through leaching of spent lead acid battery paste in citrate salt aqueous system and more economical compared with former precursor (Pb(C6H6O7)·H2O). The products were characterized by thermogravimetric–differential thermal analysis, scanning electron microscopy and X-ray diffraction. The results show that when lead citrate of columnar-shape crystals are calcined in N2 gas, orthorhombic β-PbO is the main product containing small amount of Pb and C. On combusting the citrate in air, a mixture of orthorhombic β-PbO, tetragonal α-PbO and Pb with the particle size of 100–200nm is obtained, with β-PbO as the major product. And the cyclic voltammetry measurements of lead oxides present different electrochemical redox potentials because of the different structure of lead oxide obtained from Pb3(C6H5O7)2·3H2O.

Effect of Wetting-Drying Cycles on Redistribution of Lead in Some Semi-Arid Zone Soils Spiked with a Lead Salt

Mobility and bioavailability of lead (Pb) could be affected considerably by soil physicochemical properties; however, less is known about the effect of Pb levels and aging time. This study was conducted to evaluate the effects of Pb levels and wetting-drying (WD) cycles on distribution and bioavailability of Pb in three semi-arid zone soils treated with different levels of Pb(NO3)2. Wetting-drying cycles simulated the actual field irrigation in the semi-arid soils. A soil with a long history of Pb contamination was also taken as a reference soil. The soils were spiked with various levels of Pb and incubated under WD cycles for 160 d. Sequential extractions and batch sorption experiments were performed to assess the fractionation of Pb in the spiked soils. Redistribution index (Uts) and reduced partitioning parameter (IR) were applied to semi-quantify the distribution of Pb in the spiked soils. A small amount of Pb sorbed was desorbed by the soils, indicating a strong and irreversible binding of Pb in the studied soils. Contribution of carbonate-bound (Car) and residual (Res) Pb fractions to the total Pb of the soils was more than 97%. The Car, soluble plus exchangeable (SE), and organic matter-bound (OMB) fractions of Pb were transferred to the Res fraction under the WD cycles. The IR and Uts values were influenced by Pb loading levels and WD; therefore, the Pb lability and/or redistribution pattern could semi-quantitatively be assessed via these parameters. At the end of the experiment, the Ir and Uts values for the Pb salt-spiked soils did not show the quasi-equilibrium state. The lability of Pb in the soils decreased with increasing incubation time and showed a strong dependence on Pb levels and soil chemical composition. WD cycles significantly affected the overall lability of Pb in soils through influencing the redistribution of Pb among solid-phase components.

Phase development, microstructure and optical properties of Cu2ZnSnSe4 thin films modified with Pb and Ti

For the first time we report the growth of Cu2ZnSnSe4 (CZTSe) thin films modified with Pb and Ti, and their structure, morphology and optical properties for possible photovoltaic applications. The polycrystalline films with stannite structure were grown by pulsed laser deposition from the homegrown dense targets. While a small amount of Pb was soluble in CZTSe, a higher concentration of Pb led to the distinct formation of secondary phase of PbSe. For Ti modification, however, no Ti-related secondary phase could be identified and only a minor trace of Cu2Se was detected at a high concentration of Ti. Grain growth and surface morphology of the films were affected in a different manner by the substitution of Pb and Ti. For both Pb and Ti, an initial decrease followed by a large increase in the band gap of the films was observed. The band gap tunability in the range of about 1.2 to 2.1eV by the substitutions is believed to be advantageous for photovoltaic applications.

Preparation and characterization of nano-structured lead oxide from spent lead acid battery paste

As part of contribution for developing a green recycling process of spent lead acid battery, a nanostructural lead oxide was prepared under the present investigation in low temperature calcination of lead citrate powder. The lead citrate, the precursor for preparation of this lead oxide, was synthesized through leaching of spent lead acid battery paste in citric acid solution. Both lead citrate and oxide products were characterized by means of thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and scanning electron microscope (SEM). The results showed that the lead citrate was sheet-shape crystal of Pb(C 6H 6O 7)·H 2O. When the citrate was calcined in N 2 gas, β-PbO in the orthorhombic phase was the main product containing small amount of Pb and C and it formed as spherical particles of 50–60 nm in diameter. On combusting the citrate in air at 370 °C (for 20 min), a mixture of orthorhombic β-PbO, tetragonal α-PbO and Pb with the particle size of 100–200 nm was obtained, with β-PbO as the major product. The property of the nanostructural lead oxide was investigated by electrochemical technique, such as cyclic voltammetry (CV). The CV measurements presented the electrochemical redox potentials, with reversibility and cycle stability over 15 cycles.

Magnetic properties of A- and B-site cation doped La 0.65Ca 0.35MnO 3 manganites

The La 0.65Ca 0.35MnO 3, La 0.65Ca 0.30Pb 0.05MnO 3 and La 0.65Ca 0.30Pb 0.05Mn 0.9Cu 0.1O 3 compounds, prepared by the sol–gel method and sintered in air at 1100 °C for 24 h, have been investigated by Magnetic Properties Measurements System (MPMS) to explore the effects of A- and B-site cation doping. From the measurements, the Curie temperatures ( T C ) and the isothermal magnetic entropy changes (−Δ S M ) were determined. The Curie temperature of La 0.65Ca 0.35MnO 3 compound was found to be 273 K. The Curie temperature increases to 286 K for the La 0.65Ca 0.30Pb 0.05MnO 3 compound due to the substitution of Ca by a small amount of Pb. However, replacing 10% of Mn with Cu (La 0.65Ca 0.30Pb 0.05Mn 0.9Cu 0.1O 3) leads to a reduction in the Curie temperature to 223 K. For the field change of 1 T, while the maximum magnetic entropy change for the sample La 0.65Ca 0.35MnO 3 was found to be 4.1 J/kg K it decreases down to 2.6 J/kg K and 3.2 J/kg K for the La 0.65Ca 0.30Pb 0.05MnO 3 and La 0.65Ca 0.30Pb 0.05Mn 0.9Cu 0.1O 3 samples, respectively.

Spatial Imaging and Speciation of Lead in the Accumulator Plant Sedum alfredii by Microscopically Focused Synchrotron X-ray Investigation

Sedum alfredii (Crassulaceae), a species native to China, has been characterized as a Zn/Cd cohyperaccumulator and Pb accumulator though the mechanisms of metal tolerance and accumulation are largely unknown. Here, the spatial distribution and speciation of Pb in tissues of the accumulator plant was investigated using synchrotron-based X-ray microfluorescence and powder Extended X-ray absorption fine structure (EXAFS) spectroscopy. Lead was predominantly restricted to the vascular bundles of both leaf and stem of the accumulator. Micro-XRF analysis revealed that Pb distributed predominantly within the areas of vascular bundles, and a positive correlation between the distribution patterns of S and Pb was observed. The dominant chemical form of Pb (>60%) in tissues of both accumulating (AE) and nonaccumulating ecotype (NAE) S. alfredii was similar to prepared Pb-cell wall compounds. However, the percentage of the Pb-cell wall complex is lower in the stem and leaf of AE, and a small amount of Pb appeared to be associated with SH-compounds. These results suggested a very low mobility of Pb out of vascular bundles, and that the metal is largely retained in the cell walls during transportation in plants of S. alfredii.

The effect of microstructural and geometrical features on the reliability of ultrafine flip chip microsolder joints

A thermodynamic approach was used to investigate solder alloy systems containing Sn, Ag, Sb, and Pb, during both equilibrium and Scheil cooling conditions. The modeled microstructure was used to explore recent experimental results and to establish the microstructure-property relationships in microsolder joints. This approach is shown to be very useful in the transition from Pb-Sn to lead-free solders by enabling the consideration of contamination by a small amount of Pb. Molten solder interacts with the under bump metallization or print circuit board (PCB) metallization to form intermetallic compounds (IMCs). A truncated sphere structure was used to predict the solder joint geometry, and a two-dimensional finite-element (FE) method was adopted to investigate the kinetics of the dissolution of Au during the reflow process. The dissolution of Au into different volumes of solder material for three sizes of joints has been studied. In the modeling of the dissolution kinetics, the Nernst-Brunner equation is found to have poor validity for these calculations because of the dramatic change in the microscopic geometry and boundary conditions for joints at 100 µm in size or smaller. A combined thermodynamic and kinetic modeling approach, with a novel interface for implementation, is also briefly discussed.

Uptake and accumulation of lead by roots, hypocotyls and shoots of Indian mustard [ Brassica juncea (L.)

The effects of different concentrations of lead nitrate on root, hypocotyl and shoot growth of Indian mustard ( Brassica juncea var. Megarrhiza), and the uptake and accumulation of Pb 2+ by its roots, hypocotyls and shoots were investigated in the present study. The concentrations of lead nitrate (Pb(NO 3) 2) used were in the range of 10 −5–10 −3 M. Root growth decreased progressively with increasing concentration of Pb 2+ in solutions. The seedlings exposed to 10 −3 M Pb exhibited substantial growth reduction and produced chlorosis. Brassica juncea has considerable ability to remove Pb from solutions and accumulate it. The Pb content in roots of B. juncea increased with increasing solution concentration of Pb 2+. The amount of Pb in roots of plants treated with 10 −4, 10 −3 and 10 −5 M Pb 2+ were 184-, 37- and 6-fold, respectively, greater than that of roots of the control plant. However, the plants transported and concentrated only a small amount of Pb in their hypocotyls and shoots, except for the group treated with 10 −3 M Pb 2+.

Quantitative Electron Probe Microanalysis of Bi-Sr-Ca-Cu-O High Tc Superconductors Using Energy- and Wavelength-Dispersive Spectrometry

Abstract: Multiple linear least squares (MLLSQ) and sequential simplex spectral processing procedures were used in an electron probe energy-dispersive (EDS) analysis of a 2223 Bi-Sr-Ca-Cu-O (BSCCO) high Tc superconductor specimen. This phase is normally difficult to quantify by EDS at voltages below 25 kV because of the severe overlap of the BiM lines with the M lines from a small amount of Pb that is added to the phase for stability. Quantitative results from the MLLSQ spectral processing and ZAF matrix correction procedures agreed well with wavelength-dispersive analysis (WDS) of the same specimen.

Variation of the lead content in sputtered copper–lead films due to resputtering effects

Soft tribological coatings deposited by magnetron sputtering are used as protective layers of sliding bearings in high-performance diesel engines. They consist of a tough component with a high melting point and a soft component with a low melting point. The tough component gives mechanical stability while the soft component provides the capability to embed contamination particles. The components are immiscible to prevent the formation of intermediate brittle phases. One system under investigation is copper lead. Although the chemical composition of a sputter-deposited film should generally be equal to target composition this does not hold for Cu with a small amount of Pb. The experiments showed that the Pb content of films deposited by magnetron sputtering with Ar+ ions from a planar-cast Cu 4 wt % Pb target strongly depends on the process parameters of working gas pressure and substrate temperature. Gas pressure and substrate temperature were varied from 0.3 to 5 Pa and 100 to 260 °C, respectively. The Pb content of the films was measured by energy-dispersive x-ray (EDX) analysis and compared to the actual Pb content of the target (3.7 wt % measured by AAS and EDX). Low substrate temperature or low working gas pressure yields a low Pb content. Increasing either temperature or gas pressure increases the Pb content up to target composition. These effects are explained semiquantitatively by taking into account the gas-phase transport mechanism of the sputtered particles and the adsorption mechanisms of Pb atoms on the surface of the forming film. Mechanical and structural film properties, which are also influenced by the Pb content, are evaluated by fracture, microhardness testing, and examination of microtome cuts.

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The optical absorption loss a and Faraday rotation θF in the wavelength region λ=0.5∼2.5μm are investigated for YIG films incorporated with a small amount of Pb, Ca and other ions. The contribtuions of pb2+, Pb4+, Fe2+ and Fe4+ ions to α and θF are studied by reducing the Ca-free and Ca-droped YIG films grown by LPE method. It turns out that the absorption enhancement due to Pb2+ is remarkable near the optical absorption edge, and that due to Pb4+ is remarkable at λ∼0.56μm. The strong absorption at λ∼0.56μm is thought to originate in the combined presence of Fe3+ and Pb4+. As for the Faraday rotation, it is found that the contribution by Fe4+ is negative in the θF spectra in the near infrared recion like that bv Pb2+, while the Fe2+ contribution is negligible in the measured wavelength region.