Composition Of Zn Research Articles

The zinc isotope composition of late Holocene open-ocean marine sediments

The controls on Zn burial fluxes into marine sediments are not well constrained by existing datasets. To address this problem, new Zn-isotope data have been generated from a globally distributed array of late-Holocene age sediments that accumulated in open ocean settings underneath a diverse range of depositional conditions (Namibian margin, West African margin, Arabian margin, Californian margin, Peruvian margin, Southern Ocean, Indian Ocean, North and South Atlantic Oceans, South China Sea). The mean non-detrital isotopic composition of Zn in the whole dataset (δ66/64Zn = 0.37 ± 0.25 ‰, 2. S.D., n = 33) is only slightly lower than the modern deep-ocean composition (0.45 ± 0.14 ‰). Locations with total organic carbon >1 wt% have greater non-detrital enrichments of Zn and higher Zn isotope compositions than organic-poor sites, although the uncertainties overlap. Zinc associated with organic matter burial (using Zn/C ratios) and/or oxyhydroxide burial (using Zn/Fe and Zn/Mn ratios) account for a combined total of ~16–73% of the total non-detrital Zn content of the investigated sediments, therefore requiring an additional burial flux of Zn to balance the sedimentary budget. This flux is probably related to ZnS formation although Zn incorporation into authigenic clays is also possible. The new data indicate that open-ocean marine sediments track the deep-ocean Zn isotope composition to within 0.1–0.2 ‰, except in areas where isotopically distinct Zn fractions dominate the non-detrital Zn budget. The fraction of Zn removed into different sedimentary components is used to calculate Zn residence times ranging from ~2.7 kyr to 13.5 kyr that are within the range of previous estimates based on input fluxes to the ocean.

Genetic diversity analysis of East African sorghum (Sorghum bicolor [L.] Moench) germplasm collections for agronomic and nutritional quality traits

Breeding for climate-resilient, high-yielding, and nutrient-rich sorghum cultivars is essential for sustainable food systems and enhanced livelihoods in sub-Saharan Africa. Therefore, this study aimed to determine the genetic diversity among East African sorghum germplasm collections through agronomic and nutritional quality traits to select promising lines for direct production or breeding. A collection of 348 sorghum germplasm was field evaluated at two locations in Uganda using an augmented design, and grain iron (Fe) and zinc (Zn) contents were profiled. Data were collected on 20 sorghum agro-morphological traits and Fe and Zn compositions. A significant (P ≤ 0.05) variation was detected amongst the test genotypes for all the assessed traits, suggesting the presence of sufficient genetic diversity for selection. High heritability (H2 > 0.60) and genetic advance as percent of the mean (GA >20%) were computed for grain yield, Zn content, and selected agronomic traits, ensuring genetic gains through selection. A significant positive correlation was recorded between Fe and Zn concentrations (r = 0.32, P < 0.001), allowing simultaneous selection for the two nutrient compositions. Cluster analysis based on phenotypic traits resolved the test sorghum genotypes into four distinct genetic groups. Six genotypes with superior agronomic traits and high Fe and Zn contents were identified for production or potential parents for quality breeding. Overall, the current study found considerable genetic variation among East African sorghum germplasm collections for strategic conservation and breeding in Uganda or similar agro-ecologies.

Study on the Performance of Oxygen-Rich Zn(O,S) Buffers Fabricated by Sputtering Deposition and Zn(O,S)/Cu(In,Ga)(S,Se)2 Interfaces

We developed a novel process for fabricating oxygen-rich Zn(O,S) buffer layers by magnetron reactive sputtering with a single oxygen-rich Zn(O,S) target, suitable for industrial all-dry production. Then, we successfully fabricated Cd-free Cu(In,Ga)(S,Se)2 (CIGSSe) solar cells. By varying the oxygen partial pressure during sputtering from 0 to 20%, we precisely controlled the Zn(O,S) composition, then systematically investigated its effects on the quality of oxygen-rich Zn(O,S) films, the properties of formed p-n junctions, and the performance of CIGSSe solar cells with Zn(O,S) buffer. We demonstrated that reactive sputtering with a Zn(O,S) target can generate a homogeneous, high-quality oxygen-rich Zn(O,S) buffer on large-area substrates. We observed a unique and unusual phenomenon: the appropriate content of secondary phase ZnSO4 and ZnSO3 improved the band alignment for oxygen-rich Zn(O,S). Combining our proposed schematic diagram of band alignmentat the Zn(O,S)/CIGSSe interface, we established a crucial correlation between the device performance and the interfacial properties at the p-n junction. For the CIGSSe device performance, the band alignment matching at the heterojunction plays a primary role, and the quality of oxygen-rich Zn(O,S) films plays a secondary role. Consequently, an excellent oxygen-rich Zn(O,S) buffer can be obtained with 10% Zn(O,S) deposition oxygen partial pressure , and the optimized device shows a higher Voc (447 mV) and a similar conversion efficiency (11.2%) than conventional CIGSSe devices with CdS buffer.

Varying Cu and Zn composition in brass and its effect on the fade and recovery behavior of the phenolic‐based friction composites

AbstractBrass as a functional filler in the formulation of brake friction composites helps to improve the thermal conductivity, tribo‐load bearing ability, fade, recovery and wear resistance of the brake pads. The commercial brass alloy has 70 wt% copper and 30 wt% zinc. In this work, the tribological performance of the brass powders with 60 wt% Cu +40 wt% Zn and 80 wt% Cu +20 wt% Zn having similar morphology with the commercial brass was evaluated. The commercial and the two modified versions of brass filler were introduced in the formulation. Totally nine phenolic brake composite were formulated and fabricated by varying the brass filler types and their composition (6, 8 and 10 wt%) in the brake formulations. The tribological performance of the developed brake pads was studied using a chase‐type friction tester following IS 2742 test standard. The worn surface of the tested samples was studied using scanning electron microscopy and energy‐dispersive X‐ray spectroscopy. The tribological performance of the developed samples shows a nonlinear behavior concerning the variation in the composition. Therefore, statistical evaluation techniques such as hybrid analytical hierarchy process coupled with extension evaluation method (AHP‐EEM) and analytical hierarchy process coupled with Preference Selection Index (AHP‐PSI) were used to rank the developed samples based on the multiple tribological performance parameters. Based on the evaluation process the brake composite's composition with 8 wt% brass containing 70 wt% Cu and 30 wt% Zn has given the best overall performance.

Betaine-based deep eutectic solvents mediated synthesis of zinc oxide nanoparticles at low temperature

Deep eutectic solvents (DES) are gaining popularity as a potential substitute for ionic liquids because of their lower cost and biodegradability. Betaine and phenol with melting points ∼300 °C and ∼43 °C, respectively, combine with a molar ratio of 1:2 to form a liquid at room temperature with a eutectic melting point of ∼20 °C. ZnO nanoparticles (NPs) were synthesized by using an eco-friendly and green synthesis method utilizing betaine-based DES at low temperature ∼80 °C for 2 h. X-ray diffraction analysis confirms the highly crystalline and single-phase formation of ZnO NPs with hexagonal-Wurtzite phase structure. The surface morphology of the ZnO NPs confirmed using scanning electron microscopic images revealing the mostly spherical in shape and some n-pointed stars and transmission electron microscopy images confirms that NPs are sub-100 nm in range. Also, energy dispersive X-ray results confirm the elemental composition of Zn K (∼8.6 keV) and O K (0.52 keV) to be ∼88.5 ± 1.7% and 11.5 ± 1.3%, respectively. Fourier transform infrared spectroscopy confirms the bands at 565 and 410 cm−1 is assigned to asymmetric stretching and bending vibrations of the Zn–O tetrahedron. Thermogravimetric analysis verified the thermal stability with phase purity, resulting in the formation of the single-phase crystalline ZnO NPs. UV–Vis absorption study confirms the bandgap of ∼3.1 eV. The high stability and dispersion of NPs in water confirms the interaction of DES molecules on the surface of the NPs with water. ZnO NPs incorporated in PVA thin films show strong UV–Vis absorption confirming use of these transparent thin films for UV-shielding applications. As far as we know, this study is unique, green, eco-friendly and cost-effective in that the authors were able to synthesize ZnO NPs from betaine-based DES.

Effect of Mn doping on the structural, optical, magnetic properties, and antibacterial activity of ZnO nanospheres

This work investigates the systematic study of the structural, optical, magnetic, and antibacterial properties of Mn-doped ZnO. Zinc oxide (ZnO) and Mn2+ doped zinc oxide (ZnMnO) nanoparticles (NPs), were prepared through the co-precipitation method. The X-ray diffraction studies confirmed that the synthesized nanoparticles did not modify the crystal structure upon Mn doping. However, the microstructural parameters were changed considerably upon the increase of the concentration of Mn dopant. The HRTEM images showed that the ZnO NPs exhibit nanospheres-like morphology, and a reduction in the average particle size from 41 nm to 33 nm was observed upon Mn2+ doping. The elemental composition of Zn, Mn, and O atoms were identified by EDAX spectra. The Zn–O stretching bands were observed at around 550 cm−1 in the FTIR spectra and the zinc and oxygen vacancies defects were confirmed by PL spectra. The estimated band gap of ZnO was 2.95 eV and increased to 3.14 eV for ZnMnO3. In addition, the Mn-doped ZnO NPs showed a more significant antibacterial effect than the pure ZnO NPs. The ZnO and Mn-doped ZnO NPs showed significant changes in the M-H loop where the diamagnetic behavior of ZnO changes to a weak ferromagnetic nature when doped with Mn ions. Graphical abstract

Combination of UNMIX, PMF model and Pb-Zn-Cu isotopic compositions for quantitative source apportionment of heavy metals in suburban agricultural soils

Quantitative identification of heavy metals (HM) sources in soils is key to prevention and control of heavy metal pollution. In this study, UNMIX, PMF (Positive matrix factorization) model and Pb-Zn-Cu isotopic compositions were combined to quantitatively identify heavy metal sources in a suburban agricultural area of Kaifeng, China. Using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) and ICP-MS, we measured Pb, Zn and Cu stable isotopic compositions, HM concentrations and HM chemical fractions in studied soils, as well as potential sources around the highly polluted site, including total suspended particle, compound fertilizer, irrigated river water and sediments. The results showed that total contents and chemical fractions of heavy metals, as well as Pb-Zn-Cu isotopic compositions presented great variation in different sites, which implied that heavy metal accumulation was obviously affected by local anthropogenic pollution source. UNMIX and PMF presented good agreement on source apportionment that industrial and agricultural activities (61.74% and 60.75% for UNMIX and PMF, respectively) were the major contributors to heavy metal accumulation in the study area. Especially, sewage irrigation and atmosphere deposition accounted for a large proportion (28.14% and 41.03% for UNMIX and PMF, respectively). Moreover, isotopic compositions of Pb, Zn and Cu in highly polluted soils and environment media gave further confirmation that sewage irrigation and atmosphere deposition were primary anthropogenic source. Therefore, combination of UNMIX, PMF model and Pb-Zn-Cu isotopic compositions showed good coordination in quantitative and specific source identification of heavy metals in agricultural soils.

One pot facile flash-combustion synthesis of ZnO@NiO nanocomposites for optoelectronic applications

Herein, the synthesis of the ZnO and NiO nanocomposites is reported for the first time through a facile one-pot flash-combustion. The structural, vibrational, optical, dielectric, and electrical properties of these prepared nanocomposites are systematically examined. X-ray diffraction and energy-dispersive X-ray spectroscopy studies confirm the presence of a combined phase of ZnO and NiO in the final product. The mean crystallite size, no. of dislocations, and strain values were determined to be in the range between 17 and 23 nm, 1.94 to 3.11 ( × 10−3) nm−2, and 4.17 to 5.35 ( × 10−3), respectively. TEM/HRTEM analysis was also performed on the sample prepared with higher citric acid concentration. The noticed elemental composition of Zn and Ni was 26 and 22%, respectively. The morphological study confirms the cubic crystals of NiO and nanoparticles of ZnO in the final products. The energy gap was determined using Kubelka-Munk relation and found to range between 3.19 and 3.53 eV for all studied ZnO@NiO nanocomposites. High dielectric constant and electrical conductivity while sustaining low loss values approved the promising utilization of the prepared nanocomposites in optoelectronic applications.

Coastal reclamation mediates heavy metal fractions and ecological risk in saltmarsh sediments of northern Jiangsu Province, China

Coastal reclamation has created enormous extra land for the rapidly growing economy, but it has also caused serious environmental pollution problems and threatened the sustainable development of coastal areas. However, there are few studies focusing on the distribution patterns, geochemical speciation and ecological risks of heavy metals along the land-to-sea belt, as well as the differences between reclamation and non-reclamation. Here, we collected 69 sediment samples from four sediment types along the land-to-sea sampling belts in the reclaimed and non-reclaimed tidal flats of Jiangsu, China. Geochemical speciation and contents of heavy metals were determined to investigate their spatial distributions, ecological risks and effect factors. Results showed that As, Cd, Cr and Ni in the sediments posed considerable or moderate ecological risk according to the Ontario guidelines and sediment quality guidelines (SQGs) of USEPA, but they were lower than the SQGs of China. Higher geoaccumulation index and potential ecological risk index suggested that the sediments were moderately to heavily polluted by Cd and As. Generally, reclaimed sediments exhibited higher metal pollution levels. Additionally, reclaimed areas showed a unimodal pattern of metal content along the direction of land-to-sea, suggesting that Spartina alterniflora could accelerate the deposition and accumulation of metal pollutants caused by reclamation, and ultimately control the transfer of terrigenous metals to marine environment. We found that residual fraction was the dominant geochemical fraction for the metals determined. Reclamation processes have changed the composition of heavy metal fractions, especially Cd, Pb, Zn, and Ni. Approximately 20% of Cd existed in the acid extractable/exchangeable fraction and posed medium ecological risk according to the risk assessment code. The principal component analysis and correlation matrix further indicate that organic matter and particle size of sediment could be the major factors regulating the metal distribution, and Cd and Zn might be anthropogenic sources.

Deposition of CdZnTe Films with CSS Method on Different Substrates for Nuclear Radiation Detector Applications

CdZnTe (CZT) films were grown by closed space sublimation (CSS) method on (111)-oriented CZT wafers, non-oriented CZT wafers and FTO substrates. The compositional and morphological properties of CZT films on different substrates were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), which indicated that CZT films grown on (111)-oriented CZT wafers had low dislocation density and high Zn composition. X-ray diffraction (XRD) measurements confirmed that CZT films grown on (111)-oriented CZT wafers had the best crystal quality. The I-V and DC photoconductivity measurements indicated that CZT films on (111)-oriented CZT wafer had good carrier transport performance. The energy spectra of CZT films grown on (111)-oriented CZT wafer presented that it had a good response to the nuclear radiation under 241Am.

Examining the effects of chemical cleaning, leaching, and partial dissolution on zinc and cadmium isotope fractionation in marine carbonates

The application of zinc (Zn) and cadmium (Cd) isotopes as palaeo-proxies in carbonate sediment is rapidly expanding due to their potential for tracing changes in biological productivity in the modern and past oceans. However, there are limited investigations into the chemical cleaning methods required to produce the most consistent and accurate data for these novel isotope systems. This could impact their use as palaeo-proxies to reconstruct ocean-atmosphere-climate interactions throughout Earth's history.To address this concern and expand the utility of the Zn and Cd stable isotope systems as palaeo-productivity tracers, the performance of two standard chemical cleaning protocols for acquiring robust and reliable Zn and Cd isotope datasets were assessed. These include (i) the Cd-cleaning method that uses a reductive step to selectively leach contaminating secondary iron (Fe)‑manganese (Mn) (oxyhydr)oxide coatings from the carbonate surface, and an oxidative step that is used to remove post-depositional organic matter and sulphide precipitates; and (ii) the magnesium/calcium cleaning protocol that includes an oxidative step only, leaving secondary FeMn (oxyhydr)oxide coatings largely intact. Well-preserved Holocene-, and Mesozoic-aged carbonate sediments were used to test the reliability of these two chemical cleaning methods. The Holocene samples comprised not only aliquots of bulk sediment, but also individual species of planktic and benthic foraminifera.Our results show that the best practice chemical cleaning method for retrieving consistent and accurate Zn and Cd isotope, and Zn/Ca and Cd/Ca datasets for carbonate sediments, requires both reductive and oxidative cleaning following the Cd-cleaning method. This differs from most methodological approaches applied to date that remove the reductive step from the chemical cleaning protocol and apply an oxidative step only, or no chemical cleaning at all. Inclusion of the reductive step in the chemical cleaning method typically shifts δ66Zn by ~0.1‰ lower and δ114Cd by 0.3‰ higher in the solid phase, while Zn/Ca and Cd/Ca typically decrease 2-fold. The benthic foraminifera, C. wuellerstorfi, that live in ocean bottom waters where the seawater Zn and Cd isotope composition is homogeneous display evidence of Zn and Cd isotope fractionation between seawater and carbonate on the order of 0.08 ± 0.08‰ (2SE, n = 4) and − 0.25 ± 0.13‰ (2SE, n = 4), respectively, in agreement with experimental constraints. Furthermore, evidence of Zn isotope fractionation effects are recorded in a naturally-dissolved carbonate sediment, together with laboratory-controlled carbonate dissolution experiments. Based on these results, we recommend the Cd-cleaning method and the application of Zn and Cd isotope fractionation factors to accurately reconstruct past seawater Zn and Cd isotope compositions from carbonate sediments.

Third order nonlinear optical behavior and optical limiting properties of Ni2+ ions doped zinc nano-aluminates

Nanosized Zn1-xNixAl2O4(0 ≤ x ≤ 0.5) particles were synthesized using microwave assisted combustion process with metal nitrates as starting precursors. The crystalline behavior of the synthesized samples is confirmed through the powder XRD and TEM studies. XPS studies are employed to obtain the oxidation state and the chemical elements details. HR-SEM analysis shows the morphology of agglomerated coalescence behavior. The elemental composition of Zn, Ni, O and Al was qualitatively obtained from EDX analysis. UV-DRS spectra are used to evaluate the optical band gap which is in the range of ̴ 5.45 to 3.32 eV. In FTIR spectra, two essential peaks n1 and n2 are endorsed the existence of spinel structured Zn1-xNixAl2O4 (0 ≤ x ≤ 0.5). The exothermic transitions and weight loss of elements is obtained by TG-DTA analysis. The magnetic parameters are confirmed the super paramagnetic behavior for all nickel doped zinc aluminate nanoparticles. The nonlinear optical properties are determined by Z-scan technique. It is found that the optical threshold values are in the range of 5.98, 5.25, 4.85 and 3.73 mW respectively. All the samples are exhibited the defocusing effect at CW laser.

Toxic metal concentrations and Cu\u2013Zn\u2013Pb isotopic compositions in tires

BackgroundParticles from non-exhaust emissions derived from traffic activities are a dominant cause of toxic metal pollution in urban environments. Recently, studies applying multiple isotope values using the Iso-source and positive matrix factorization (PMF) models have begun to be used as useful tools to evaluate the contribution of each pollution source in urban environments. However, data on the metal concentrations and isotopic compositions of each potential source are lacking. Therefore, this study presents data on toxic metals and Cu, Zn, and Pb isotopic compositions in tires, which are one of the important non-exhaust emission sources.FindingsAmong the toxic metals, Zn had the highest concentration in all tire samples, and the mean concentrations were in the order of Zn > Cu > Pb > Sn > Sb > Ni > Cr > As > Cd. Ni, Zn, Sn, and Sb had higher concentrations in domestic tires (South Korea), and the Cu, Cd, and Pb concentrations were relatively higher in imported tires. The mean values of δ65CuAE647, δ66ZnIRMM3702, and 206Pb/207Pb ranged from − 1.04 to − 0.22‰, − 0.09 to − 0.03‰, and 1.1242 to 1.1747, respectively. The concentrations and isotopic compositions of Cu and Pb in the tires showed large differences depending on the product and manufacturer. However, the differences in Zn concentration and δ66ZnIRMM3702 values were very small compared with those of Cu and Pb. The relationships of the Zn concentration and isotopic composition showed that domestic tires are clearly distinguishable from imported tires. Bi-plots of Cu, Zn, and Pb isotopic compositions indicated that tires can be clearly discriminated from natural-origin and other non-exhaust traffic emission sources.ConclusionsThe multi-isotope signatures of Cu, Zn, and Pb exhibited different isotopic values for other non-exhaust traffic emission sources than for tires, and application of the multi-isotope technique may be a powerful method for distinguishing and managing non-exhaust sources of metal contamination in urban environments.

Effects of Composition on the Electromagnetic Wave Shielding/Absorption and Corrosion in Zn-Ni Alloy Thin Film

In the Fourth industrial age, there is increasing use of electronic devices with high frequency (GHz) operating circuits for radio wave transmission/reception. This can lead to electromagnetic noise, and malfunctions in nearby devices. Electromagnetic shielding technology has emerged as an important way of preventing device malfunctions due to noise, and interest in shielding materials for electromagnetic waves has also increased. To allow compact integration and light weight electronic devices, highly efficient, thin and multifunctional film materials are required. This study selected the Zn-Ni alloy, which has adequate corrosion resistance, to protect the metal parent material of electronic components. Various compositions of the alloy were deposited using magnetron sputtering. Phase formation and composition were confirmed through XRD and SEM and EDS. The surface resistance of the thin films was measured using the 4point probe method, to calculate the shielding rate of the thin films. The electromagnetic wave shielding/absorption rate then measured according to frequency and the results compared with the calculated values. Corrosion resistance was evaluated with a polarization test. The far field electromagnetic shielding/absorption rate increased as the Zn content increased, up to 52 dB in a film with 70 at% of Zn. Corrosion resistivity behavior was the opposite. However, the Ni5Zn21 phase formation, which occurred in films with lower Zn composition, helped to improve electromagnetic absorption in the near field as well as corrosion resistivity. Therefore, the optimum composition of the Zn-Ni films was provisionally determined to be around Ni: Zn = 43:57 for electronic devices using electromagnetic waves in the near field range.

Investigation of selective leaching conditions of ZnO, ZnFe2O4 and Fe2O3 in electric arc furnace dust in HNO3

Electric arc furnace dust (EAFD) includes mainly Zn, Fe, Pb, Ca and Mn-bearing compounds. Thus, EAFD is classified as a hazardous waste. The dissolution behavior of Zn- and Fe-bearing compounds in EAFD in nitric acid solutions was investigated in this work. The composition of Zn- and Fe-bearing compounds in the EAFD was determined as 28.58, 37.96 and 11.33 % for ZnO, ZnFe2O4 and Fe2O3, respectively. The effect of stirring speed, temperature and HNO3 concentration on the dissolution rate of ZnO, ZnFe2O4 and Fe2O3 were investigated and optimum leaching conditions determined. While ZnO was dissolved rapidly, the dissolution rate of ZnFe2O4 increased with increasing temperature and HNO3 concentration. Fe2O3 was not soluble in 0.5 M HNO3 solution at 40?C, whereas it was dissolved completely in 4 M HNO3 solution at 80?C.

The Zn, S, and Cl isotope compositions of mare basalts: Implications for the effects of eruption style and pressure on volatile element stable isotope fractionation on the Moon

AbstractWe compare the stable isotope compositions of Zn, S, and Cl for Apollo mare basalts to better constrain the sources and timescales of lunar volatile loss. Mare basalts have broadly elevated yet limited ranges in δ66Zn, δ34S, and δ37ClSBC+WSC values of 1.27 ± 0.71, 0.55 ± 0.18, and 4.1 ± 4.0‰, respectively, compared to the silicate Earth at 0.15, –1.28, and 0‰, respectively. We find that the Zn, S, and Cl isotope compositions are similar between the low- and high-Ti mare basalts, providing evidence of a geochemical signature in the mare basalt source region that is inherited from lunar formation and magma ocean crystallization. The uniformity of these compositions implies mixing following mantle overturn, as well as minimal changes associated with subsequent mare magmatism. Degassing of mare magmas and lavas did not contribute to the large variations in Zn, S, and Cl isotope compositions found in some lunar materials (i.e., 15‰ in δ66Zn, 60‰ in δ34S, and 30‰ in δ37Cl). This reflects magma sources that experienced minimal volatile loss due to high confining pressures that generally exceeded their equilibrium saturation pressures. Alternatively, these data indicate effective isotopic fractionation factors were near unity.Our observations of S isotope compositions in mare basalts contrast to those for picritic glasses (Saal and Hauri 2021), which vary widely in S isotope compositions from –14.0 to 1.3‰, explained by extensive degassing of picritic magmas under high-P/PSat values (&amp;gt;0.9) during pyroclastic eruptions. The difference in the isotope compositions of picritic glass beads and mare basalts may result from differences in effusive (mare) and explosive (picritic) eruption styles, wherein the high-gas contents necessary for magma fragmentation would result in large effective isotopic fractionation factors during degassing of picritic magmas. Additionally, in highly vesiculated basalts, the δ34S and δ37Cl values of apatite grains are higher and more variable than the corresponding bulk-rock values. The large isotopic range in the vesiculated samples is explained by late-stage low-pressure “vacuum” degassing (P/PSat ~ 0) of mare lavas wherein vesicle formation and apatite crystallization took place post-eruption. Bulk-rock mare basalts were seemingly unaffected by vacuum degassing. Degassing of mare lavas only became important in the final stages of crystallization recorded in apatite—potentially facilitated by cracks/fractures in the crystallizing flow. We conclude that samples with wide-ranging volatile element isotope compositions are likely explained by localized processes, which do not represent the bulk Moon.

Drop Calorimetric Measurement of In-Zn system for Lead-Free solder applications

Circuit boards installed inside vehicles in the automotive industry are subjected to significant thermal stress due to temperatures above 150 °C. It can be reduced by using In-Zn solder alloys instead of hazardous Pb-based solder alloys, representing Pb-free solder alloys' development. The formation of an alloy is determined by its phase diagram, which is then measured to determine its thermodynamic properties. Using a drop calorimeter, the mixing heat effect (mixing enthalpy) as partial enthalpies and integral enthalpies of mixing in the liquid phase of In-Zn systems were investigated at 800 K and 900 K. The plots of mixing enthalpies are plotted versus zinc composition. When the Redlich–Kister polynomial is fitted, it is compared to our experimental data to identify the binary interaction parameters. This will help to predict the thermodynamic properties of multicomponent systems by using values of interaction parameters of the binary system (In-Zn). For all compositions at 800 K and 900 K, the model value was found to be close to the experimental values. The integral enthalpy of mixing of In-Zn system at 800 K and 900 K is endothermic in nature all through the composition and its most value in the range of XZn ∼ 0.48–0.52. It is also visible that the enthalpy of mixing is symmetrical with the composition of Zn.

The 1991 explosive Hudson volcanic eruption as a geochronological marker for the Northern Antarctic Peninsula

It is estimated that the explosive Hudson volcano eruption in Southern Chile injected approximately 2.7 km3 of basalt and trachyandesite tephra into the troposphere between August 8-15, 1991. The Hudson signal has been detected in Antarctica at the eastern sector and in South Pole snow. In this work, we track the Hudson volcanic plume using a dispersion model, remote sensing, and a re-analysis of a high-resolution ice core analysis from the Detroit Plateau in the Antarctic Peninsula and sedimentary records from shallow lakes from King George Island (KGI). The Hudson eruption imprint in these records is confirmed by using a weekly resolved aerosol concentration database from KGI demonstrating that the regional impact of Hudson eruption predominates over the Mount Pinatubo/Phillippines volcanic signal, dated from June 1991, in terms of particulate matter depositions. The aerosol elemental composition of Ca, Fe, Ti, Si, Al, Zn, and Pb increases from 2 to 3 orders of magnitude in background level during the days following the eruption of the Hudson volcano.

Zn-assisted modification of the chemical structure of N-doped carbon dots and their enhanced quantum yield and photostability.

This article presents the Zn-assisted synthesis of N-doped carbon dots (N-CDs) with an enhanced quantum yield (QY) and photostability. There have been intensive studies to improve or tune the optical properties of carbon dots (CDs) to meet the demand for luminescent materials in various fields, including energy conversion, photocatalysis, bioimaging, and phototherapy. For these applications, the photostability of the CDs is also a critical factor, but the related studies are relatively less common. The Zn-assisted N-CDs (denoted as Zn:N-CDs) obtained by the addition of Zn(OAc)2 to the precursors during the synthesis of N-CDs not only exhibited an enhanced quantum yield but also improved photostability compared to those of N-CDs. A comprehensive study of the chemical composition of Zn:N-CD and N-CD using X-ray photoelectron spectroscopy indicated a correlation between their chemical structure and photostability. Zn(OAc)2, which acts as a catalytic reagent, induced the modification of chemical structures at the edges of carbogenic sp2 domains, without being doped in N-CD, and the heteroatom–carbon bonds in Zn:N-CD seemed to be more resistant to light compared to those in N-CDs. The increased QY and photostability of Zn:N-CDs make them more suitable as an optical probe and they could be used in fingerprint identification. With Zn:N-CDs, the microstructure of fingerprints was confirmed clearly for a long duration effectively.

Conduction Band Offset Effect on the Cu2ZnSnS4 Solar Cells Performance

Among the causes of the degradation of the performance of kesterite-based solar cells is the wrong choice of the n-type buffer layer which has direct repercussions on the unfavorable band alignment, the conduction band offset (CBO) at the interface of the absorber/buffer junction which is one of the major causes of lower VOC. In this work, the effect of CBO at the interface of the junction (CZTS/Cd(1-x)ZnxS) as a function of the x composition of Zn with respect to (Zn+Cd) is studied using the SCAPS-1D simulator package. The obtained results show that the performance of the solar cells reaches a maximum values (Jsc = 13.9 mA/cm2, Voc = 0.757 V, FF = 65.6%, ɳ = 6.9%) for an optimal value of CBO = -0.2 eV and Zn proportion of the buffer x = 0.4 (Cd0.6Zn0.4S). The CZTS solar cells parameters are affected by the thickness and the concentration of acceptor carriers. The best performances are obtained for CZTS absorber layer, thichness (d = 2.5 µm) and (ND = 1016 cm-3). The obtained results of optimizing the electron work function of the back metal contact exhibited an optimum value at 5.7 eV with power conversion efficiency of 13.1%, Voc of 0.961 mV, FF of 67.3% and Jsc of 20.2 mA/cm2.