Distribution Of Aluminum Research Articles

Comparative study of the structure and properties of homogeneous and gradient Ni-Cr-Al coatings

This paper compares the structure and properties of homogeneous and gradient coatings in the Ni-Cr-Al system obtained by detonation spraying. According to X-ray analysis, only the CrNi3 phase appears in the homogeneous coating, and CrNi3 , Al, and NiAl phases appear on the gradient coating. The elements distribution graphs show that a small amount of aluminum is distributed over the depth of the homogeneous coating and in the gradient coating. The distribution of aluminum in the gradient Ni-Cr-Al coating gradually increases from the depth to the surface, and a high amount of aluminum forms in the coating surface. According to EDS analysis, a small amount of aluminium is distributed on the surface of the homogeneous coating and a large amount on the gradient coating. In the gradient coating, aluminium gradually increases from the substrate surface to the coating surface. Also, the gradient coating has a higher hardness than the homogeneous coating.

缙云山4种林分土壤无机磷与活性铝的含量及分布

PDF HTML阅读 XML下载 导出引用 引用提醒 缙云山4种林分土壤无机磷与活性铝的含量及分布 DOI: 10.5846/stxb202101090092 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 重庆市社会民生类重点研发项目（cstc2018jscx-mszdX0080）；国家自然科学基金项目（31570599） Content and distribution of inorganic phosphorus and labile aluminum in soil of four forest types in Jinyun Mountain Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探索不同林分对土壤中无机磷与活性铝的含量及分布的影响，以及无机磷与活性铝之间的相互关系，以在我国西南地区酸性土壤上的农林经营管理提供理论和实践依据。研究以缙云山广泛分布的4种林分类型：山莓、马尾松、楠竹和柑橘林土壤为对象，采用酸性土壤无机磷分级方法和铝试剂比色法测定了土壤剖面A、B和C层中各形态的无机磷与活性铝的含量，分析了不同林分土壤中无机磷和活性铝的含量和分布特征。结果表明，林分类型显著影响土壤中无机磷与活性铝的含量与分布，且铁磷（Fe-P）、交换态铝（Ex-Al）和羟基铝（Hy-Al）的含量和比例还受到土壤层次的影响。4种林分相比，山莓林能促进闭蓄态磷（O-P）的形成，而马尾松、楠竹和柑橘林则有利于Al-P、Fe-P和Ca-P的形成；柑橘林有利于低活性的腐殖酸铝（Al-AH）形成，而山莓、马尾松和楠竹林促进高活性的Ex-Al或Hy-Al溶出；Ex-Al、Al-P和Fe-P在土层的分布上有表层富集现象，而Hy-Al集中分布于B层。此外，土壤Ex-Al和Al-P与Fe-P之间，Hy-Al和Ca-P之间均呈显著（P<0.05）正相关。因此，林分类型显著影响土壤无机磷与活性铝的含量与分布，高活性铝的溶出显著影响Al-P、Fe-P和Ca-P含量。 Abstract:Phosphorus (P) is an essential element for plant growth, development and metabolism. Soil is a direct donor of phosphorus for plants. Generally, total phosphorus (TP) is plenty in most soils, but its availability to plants is very low. Aluminum (Al) is the most abundant metal element in the earth's crust. When the soil is getting acidified, Al in the forest soil can be activated into Al3+ (exchangeable Al, Ex-Al) or Al (OH)2+, Al (OH)2+ (hydroxyl-Al, Hy-Al), which might precipitate HPO42-, H2PO4-, and PO43- into hard-to-dissolve P and reduce the P availability in consequence. How to prevent the decrease of P availability caused by the dissolution of Al from acidic soil, which is one of the urgent problems to be solved in forest land management. Forest type and soil layer might affect the characteristics and relationships between inorganic phosphorus (IP) and labile Al, which remains poorly understood up to now. The present study aimed to determine the influence of forest type and soil layer on the concentration and distribution of IP and labile Al in soil, in addition to the correlation between labile Al and IP. The soil was collected by digging in three soil layers (A, B and C layer) of four forest types of Rubus corchorifolius, Pinus massoniana, Phyllostachys pubescens and Citrus reticulata forest in Jinyun Mountain, Chongqing, China. Concentrations of IP and labile Al fractions were measured using the traditional method. Results showed that concentrations and proportions of IP and labile Al in soil were significantly affected by forest types and that of iron-bound P (Fe-P), Ex-Al and Hy-Al in soil were significantly different in soil layers. Among the four forest types, Rubus corchorifolius promoted the formation of occluded P (O-P). Whereas, Pinus massoniana, Phyllostachys pubescens and Citrus reticulata were in favor of the formation of aluminum-bound P (Al-P), Fe-P and calcium-bound P (Ca-P). Citrus reticulata was favorable for the formation of low-active Al species (humic acid-Al, Al-AH), while Rubus corchorifolius, Pinus massoniana and Phyllostachys pubescens contributed the dissolution of labile Al from low-active into high-active species (Ex-Al or Hy-Al). In soil layers, Ex-Al, Al-P and Fe-P mainly enriched in the surface among the three soil layers. Hy-Al concentrated in the second soil layer. Meanwhile, the correlations were significantly positive between Ex-Al and Al-P and Fe-P or between Hy-Al and Ca-P in the soil of four forest types. The concentration and distribution of IP and labile Al fractions in soil were significantly affected by forest types. The dissolution of labile Al from low-active into high-active species significantly affected the concentrations of Al-P, Fe-P and Ca-P. This study can provide theoretical and practical basis for the management of agriculture and forestry on acid soils in southwest China. 参考文献 相似文献 引证文献

Controlling the distribution of aluminum in a Cu–zeolite catalyst by seed-assisted synthesis to improve its NH3-SCR activity

Seed-assisted synthesis controls the Al distribution of KFI zeolite, which gives rise to a superior SCR activity of Cu-KFI catalyst by mediating Cu–framework interactions.

Ammonia and Water in Zeolites Effect of Aluminum Distribution on the Heat of Adsorption

Ammonia and Water in Zeolites Effect of Aluminum Distribution on the Heat of Adsorption

Luminescence features of bulk crystals β-(Ga-=SUB=-x-=/SUB=-Al-=SUB=-1-x-=/SUB=-)-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-

This work is devoted to the study of the luminescence inhomogeneity nature of bulk (GaxAl1-x)2O3 samples grown by the Czochralski method. In the study of sample cleavages by the local cathodoluminescence method, regions with different luminescence were observed. To determine the cathodoluminescence contrast nature, we studied the uniformity of the aluminum distribution, the surface topography, and compared the luminescence spectra and the kinetics of emission bands for different regions of the sample. Also, to determine the luminescence bands nature, the crystal was annealed in air at 1000oC. This made it possible to observe the change in luminescence for the same region of the sample. Based on the studies performed, it was concluded that inhomogeneous luminescence is associated with the distribution of point defects. Upon annealing in air, the transformation of nonradiative recombination centers into luminescent centers was observed. Keywords: gallium oxide, luminescence, point defects.

Study on the Framework Aluminum Distributions of HMOR Zeolite and Identification of Active Sites for Dimethyl Ether Carbonylation Reaction※

Study on the Framework Aluminum Distributions of HMOR Zeolite and Identification of Active Sites for Dimethyl Ether Carbonylation Reaction^※

Assessment of Spatial Variability of Heavy Metals (Pb and Al) in Alluvial Soil around Delta State University of Science and Technology, Ozoro, Southern Nigeria

Soil heavy metals pollution is a major global threat, because of its impact to plants, animals, and the soil geotechnical properties. Geostatistical method was used to investigate the spatial distributions of aluminum and lead within a section of the Delta State University of Science and Technology, Ozoro, Nigeria. A total area of 1 km2 (100 hectares) was covered within the school environment. Twenty -five (25) topsoil samples were collected, at the end of the dry season (March 2021); when the water table in the study area was very low. The lead and aluminum concentrations of the 25 samples were measured by using the Association of Official Analytical Chemists (AOAC) approved methods. Using a geostatistical tool, the lead and aluminum concentrations and distribution in the soil were plotted on predication maps. The maps revealed irregular spatial distributions of lead and aluminum ions within the study area. The lead concentration was highest at the North-central region of the study area; while lead concentration was lowest at the Eastern region of the study area. In terms of the aluminum metal, the highest aluminum concentration was observed in the North eastern region; while aluminum concentration was lowest at the South western region. Data obtained from this study will be useful for agricultural and civil engineering purposes, mainly in the area of decision-making.

Improving the Specific Surface Area of Etched Aluminum Foil by Fabricating the Micro/Nano Structure

Aluminum foil with micro/nano structure has been prepared by electrochemical DC etching and a subsequent anodization treatment followed by removal of the alumina film. When the micron-sized tunnels were generated on the etched aluminum foil, the size and distribution of the nano-concave formed on the sidewall of the etched tunnels varied with the anodized time in H2SO4 and C4H6O6 electrolyte. The optimal value of the specific surface area for the aluminum foil with micro/nano structure is approximately four times larger than that of the only etched aluminum foil. It is indicated from the chronoamperometry and BET measurements that the specific capacitance of aluminum foil with micro/nano structure can be significantly improved by suitable anodization in H2SO4 electrolyte, in comparison with a comparatively small increasement in C4H6O6 electrolyte. This can be attributed to the fact that the tardy anodization process will consume a considerable amount of aluminum substrate, resulting in the aggravation of the merged tunnels.

Distribution and enrichment of Al-Li-Ga-REEs in the High-Alumina coal of the Datong Coalfield, Shanxi Province, China

The content, distribution, and origin of aluminum, lithium, gallium, and rare earth elements (REEs) in the Permo-Carboniferous coal of the Datong coalfield, China, were investigated using optical microscopy and field-emission scanning electron microscopy in conjunction with energy-dispersive X-ray spectrometry, X-ray powder diffraction, and inductively coupled plasma mass spectrometry. The Permo-Carboniferous coal of the Datong coalfield had a high volatile bituminous rank (Ro,max = 0.72% on average), and low sulfur and medium ash contents (0.58% and 25.74% on average, respectively). The main minerals in the Datong coal included kaolinite, boehmite, muscovite, calcite, dolomite, siderite, aluminum phosphate, and quartz. Of these, kaolinite, boehmite, calcite, quartz, and phosphates mainly occurred as cell fillings, indicating an authigenic origin. Compared to hard coals worldwide, the Datong coal is enriched in SiO2 (49.12%; up to 89.93%), Al2O3 (38.88%; up to 71.37%), Li (67 μg/g; up to 354.1 μg/g), Ga (18.1 μg/g; up to 70.2 μg/g), Y (20.8 μg/g; up to 46.1 μg/g), La (34 μg/g; up to 158.5 μg/g), Ce (61.3 μg/g; up to 353.8 μg/g), Tb (0.7 μg/g; up to 3.0 μg/g), Er (2.3 μg/g; up to 5.7 μg/g), and Yb (2.2 μg/g; up to 5.4 μg/g). High-alumina coal (Al2O3 content in ash > 40%) occurred in the northern and southern parts of the coalfield. In the No. 3–5 coal seam, the areas of Li enrichment were located in the north and middle of the coalfield. In the Tashan and Chaigou mines, the Ga content exceeded 30 μg/g. An area of REEs enrichment (REEs content > 300 μg/g) was identified in the Tashan and Xiaoyu mines. In the No. 3–5 coal seam, the REEs distribution pattern showed a wide and gentle “V” curve with a high left and a low right limb. These seams were characterized by a marked depletion in Eu (δEu = 0.51) and a weak negative Ce anomaly (δCe = 0.95). In the No. 3–5 coal seam, Al, Li, Ga, and REEs mainly occurred in kaolinite. Boehmite and phosphate minerals were the main carriers of Ga and REEs, respectively. The enrichment in Al-Li-Ga-REEs in the No. 3–5 coal seam was mainly influenced by the sedimentary provenance and the environment of coal accumulation. The sediment sources were oxidized bauxite in the weathering crust of the Benxi Formation and the Middle Proterozoic moyite of the Yinshan Oldland to the north and west of the coalfield. Al, Li, Ga, and REEs were transported from the source region as solutes and colloids, and they became enriched in the swamp facies of the delta plain. The Li, Ga, and REEs contents gradually increased from the bottom to the top of the Permo-Carboniferous coal seam. This increase is mainly attributed to the weak influence of seawater. The marked enrichment in heavy REEs at the bottom of the No. 5 coal seam may be related to marine transgression.

Aluminum distribution in mordenite-zeolite framework: A new outlook based on density functional theory calculations

On the basis of the density functional theory (DFT) calculations, the successive isomorphic substitution of one to six tetrahedrally coordinated Si cations by trivalent Al was systematically studied. As a result of exploring a significant number of configurations, without using a priori assumptions, it was found that the Al atoms are accommodated according to the ground state sequence in the tetrahedral sites TI ​− ​TIII ​− ​TIII ​− ​TI ​− ​TIII ​− ​TIII. The results in the general show: a) Al cations preferentially occupy TIII positions, b) the distribution of cations in the framework does not violate Löwenstein’s rule, c) the distribution of cations in the framework does not satisfy Dempsey’s rule, and d) only one Al cation is found per ζ-cage.

Effectiveness of deep lime placement and tillage systems on aluminum fractions and soil chemical attributes in sugarcane cultivation

Combining deep soil tillage systems with lime application is a potential strategy for improving the sugarcane production in acidic soils. The authors evaluated the influence of tillage systems and lime application on sugarcane performance and soil attributes, including acidity. A field study in a clayey-textured Rhodic Hapludox soil was conducted with sugarcane for two growing seasons utilizing a 3 × 2 factorial scheme comprising three soil tillage systems with and without lime: conventional soil tillage system (CT), deep strip-tillage system (DT) and modified deep strip-tillage system (MDT). The soil tillage systems differed in the depth of soil disturbance and/or lime positioning. In addition to sugarcane stalk and sugar yields, pH, potential acidity (Pac), soil organic carbon (SOC), solid-phase and soil-solution calcium (Ca) and magnesium (Mg), the percentage distribution of exchangeable (%Alex) and non-exchangeable aluminum (%Alne) in the solid phase, and total monomeric (%TM-Al) in soil water extracts were analyzed and determined. The positioning of lime by the different tillage systems influenced the distribution of the Al fractions. TM-Al existed exclusively as organic monomeric Al (OM-Al) and showed little influence from treatments. In contrast, the distribution of Alex and Alne were highly influenced by lime and tillage system and varied according to the tillage efficiency of soil amendment. Soil chemical attributes and yield parameters were also influenced by the treatments in both growing seasons, highlighting the residual effect of liming. The soil chemical attributes influenced the Al fractions. Soil pH and exchangeable and soluble calcium (Caex and Cas) and magnesium (Mgex and Mgs) explained the variation of %Alne. Pac correlated with %Alex, whereas SOC explained the variation of %TM-Al. In general, the sucrose concentration, total recoverable sugar and stalk and sugar yields were increased by lime addition in plant cane and by lime addition and tillage systems in second ratoon. The stalk yield was highest in MDT, whereas the sugar yield was highest in both deep tillage systems.

Identification of the Calcium, Aluminum, and Magnesium Distribution within Millimeter-Sized Extraterrestrial Materials Using Nonresonant X-ray Raman Spectroscopy in Preparation for the Hayabusa2 Sample Return Mission.

The nondestructive investigation of millimeter-sized meteoritic materials is often hindered by self-absorption effects. Using X-ray-based analytical methods, the information depth for many elements (Z < 30) is in the range of up to only a few hundred micrometers, and for low-Z elements (Z < 20), this is reduced even further to only a few tens of micrometers. However, the investigation of these low-Z elements, in particular calcium, aluminum, and magnesium, is of great importance to planetary geologists and cosmochemists, as these elements are regularly used to characterize and identify specific features of interest in extraterrestrial materials, especially primitive chondritic material. In this work, nonresonant inelastic X-ray scattering from core electrons was performed at beamline ID20 of the ESRF in a direct tomography approach in order to visualize these low-Z elements within the millimeter-sized meteoritic samples. The obtained 3D elemental distribution volumes were compared to results from X-ray fluorescence-CT and absorption CT experiments and were found to be in good agreement. Additionally, several regions of interest could be identified within the inelastic scattering volumes, containing information that is not available through the other presented means. As such, the proposed approach presents a valuable tool for the nondestructive investigation of low-Z elemental distributions within millimeter-sized extraterrestrial materials, such as the samples of the Hayabusa2 sample return mission.

Pinpointing and Quantifying the Aluminum Distribution in Zeolite Catalysts Using Anomalous Scattering at the Al Absorption Edge.

The location of aluminum in a zeolite framework structure defines the accessibility and geometry of the catalytically active sites, but determining this location crystallographically is fraught with difficulties. Typical zeolite catalysts contain only a small amount of aluminum, and the X-ray scattering factors for silicon and aluminum are very similar. To address this problem, we have exploited the properties of resonant X-ray powder diffraction across the Al K edge, where the aluminum scattering factor changes dramatically. By combining conventional synchrotron powder diffraction data with those collected at energies near the X-ray absorption edge, aluminum is highlighted. In this way, the different distributions of aluminum in two FER-type zeolites with identical chemical compositions but different catalytic properties could be determined unambiguously. The results are consistent with previous studies, but quantitative. This approach constitutes a major advance in our fundamental understanding of the relationship between zeolite structure and catalytic activity.

Analysis of Ionic-Exchange of Selected Elements between Novel Nano-Hydroxyapatite-Silica Added Glass Ionomer Cement and Natural Teeth.

One of the foremost missions in restorative dentistry is to discover a suitable material that can substitute lost and damaged tooth structure. To this date, most of the restorative materials utilized in dentistry are bio-inert. It is predicted that the addition of nano-HA-SiO2 to GIC matrix could produce a material with better ion-exchange between the restorative material and natural teeth. Therefore, the aim of the current study was to synthesize and investigate the transfer of specific elements (calcium, phosphorus, fluoride, silica, strontium, and alumina) between nano-hydroxyapatite-silica added GIC (nano-HA-SiO2-GIC) and human enamel and dentine. The novel nano-hydroxyapatite-silica (nano-HA-SiO2) was synthesized using one-pot sol-gel method and added to cGIC. Semi-quantitative energy dispersive X-ray (EDX) analysis was carried out to determine the elemental distribution of fluorine, silicon, phosphorus, calcium, strontium, and aluminum. Semi-quantitative energy dispersive X-ray (EDX) analysis was performed by collecting line-scans and dot-scans. The results of the current study seem to confirm the ionic exchange between nano-HA-SiO2-GIC and natural teeth, leading to the conclusion that increased remineralization may be possible with nano-HA-SiO2-GIC as compared to cGIC (Fuji IX).

The physicochemical properties and distribution of aluminum in the environment, the effect on living organisms, the reduction of its toxic effect

The review examines the physicochemical properties, distribution in the environment, the effect on living organisms, including toxicity and ecotoxicity, ways of removing aluminum and its compounds from the human and animal organism. Analysis of scientific literature has shown that the widespread use of aluminum in nature, its use in the agricultural, food, cosmetic, aluminum, oil-producing industries, medicine, water treatment processes and other fields of activity leads to an increased intake of this element into the human body. The cumulative nature of the toxic effect of aluminum and its compounds leads to negative consequences for the respiratory, nervous, musculoskeletal systems, and mammary glands.

Silica-based microspheres with aluminum-iron oxide shell for diagnosis and cancer treatment

Monodispersed silica-based microspheres have been prepared by hydrolysis and condensation of tetraethoxysilane (TEOS) in a water–ethanol mixed solution using dodecylamine (DDA) as hydrolysis catalyst and template. Core-shell samples were produced by electrostatic attraction and heterogeneous nucleation of alumina or mixed alumina and iron oxide (1:1) shells on mesoporous silica core microspheres. The iron oxide embedded in the shell structure may be considered both for contrast improvement in magnetic resonance imaging and for the local treatment of cancer by hyperthermia. SEM/TEM analysis proves the spherical shape of the silica particles, the shell development on their surface as well as the distribution of aluminum and iron in the whole shell. The outermost layer of the microspheres was primary investigated by XPS, while the structural characterization of the samples was achieved using XRD, FTIR, EPR and NMR techniques.

Mapping an archaeological site: Interpreting portable X-ray fluorescence (pXRF) soil analysis at Boroughgate, Skelton, UK

Integrating chemical soil analysis with visual inspection of an archaeological excavation may enhance our knowledge of anthropogenic activities from past populations. Elemental distribution of excavated soil from a medieval longhouse at Boroughgate, Skelton, UK was investigated. Soil was extracted from the surface of a longhouse and nearby ditch, analysed using portable X-Ray fluorescence (pXRF), and data were processed into elemental heat maps. The distribution and archaeological associations of magnesium, aluminium, phosphorus, sulphur, potassium, calcium, manganese, iron and zinc were assessed. Elemental concentrations were combined to produce a simplified summary that aided the interpretation of the site, including the delimitation of internal and external zones, clean and refuse zones, and potential animal occupation or waste areas. The application of pXRF was successful at visualising elemental distribution of an excavation to explore the anthropogenic associations through interpretation heat maps.

Distribution, Drivers, and Threats of Aluminum in Groundwater in Nova Scotia, Canada

Increased rates of acid deposition derived from the burning of fossil fuels over the last century have resulted in the acidification and increase in aluminum (Al) levels in freshwaters and soils in sensitive areas. While the acidification of surface waters such as lakes and rivers has been extensively studied, the acidification status and resulting Al concentrations in groundwater are poorly understood. Here we aim to describe the distribution of Al in groundwater across the province of Nova Scotia, Canada. We investigate the hydrogeological conditions that influence Al concentrations in groundwater and compare Al concentrations to legislated threshold levels for human and aquatic health. We found groundwater Al concentrations to be highest in areas underlain by plutonic and metamorphic bedrock types as well as surficial aquifers, with pH and organic carbon concentrations having the strongest correlation with groundwater Al concentrations. Few samples exceed the maximum acceptable concentration of 2900 µg/L released by Health Canada (2021), but these exceedances are important to highlight given the challenges with respect to Al treatment in private domestic wells and our evolving understanding of Al impacts to human health. High concentrations of Al in groundwater may also be exported to surface waters such as rivers and lakes, where they can be harmful to aquatic populations such as Atlantic salmon (Salmo salar). We recommend that private well owners test their water supplies for Al, and that further studies on Al export from groundwater to surface water be carried out in the most high-risk areas coincident with important Atlantic salmon river watersheds.

Effect of narrow pulse width laser cleaning on corrosion resistance of A5083-H111 aluminum alloy

Purpose The purpose of this paper is to promote the corrosion resistance of the 5083-111H aluminum alloy by laser cleaning. Design/methodology/approach Laser with 2 ns pulse width was adopted in this project and the corrosion resistance of cleaned samples was tested by copper-accelerated salt spray (CASS). The surface morphology, elemental composition and distribution were then characterized by SEM. Moreover, surface morphology, elemental composition and distribution were also tested. Findings Results suggested a higher corrosion resistance was successfully obtained by laser cleaning. Compared with samples cleaned by 2000 grit sandpaper, mechanical cleaning resulted in a 53% larger height difference between the peak and valley. The content of the oxygen is 8.85% on the surface cleaned mechanically and the distribution is dependent on the distribution of aluminum whereas that of the laser cleaning sample is 24.41% and the distribution existed even in the Al-poor area. Originality/value In this project, the 2-ns laser cleaning was proved to have the capability to remove the oxide layer on the aluminum alloy surface while retaining an excellent corrosion resistance and smooth surface. Meanwhile, a thorough elemental distribution and smaller grain size lead to a smaller difference in elemental concentration. This retards the diffusion of oxygen into the substrate and hence increases the corrosion resistance of the surface.

Metal diffusion model in polymer matrices in vapor phase infiltration

Metal induction into polymers is an emerging technology that could add inorganic characteristics to organic polymers. The organo-metal precursors dissolve into a polymer matrix from the surface to diffuse throughout the film thickness. In this article, the diffusion of the trimethylaluminum (TMA) in three kinds of polymers; poly(methyl methacrylate) (PMMA), poly(4-vinylpyridine) (P4VP) and poly(N-isopropylacrylamide) (PNIPAM) is discussed. TMA diffusiveness in each polymer was estimated by measuring the depth-profiles of aluminum distribution in the polymer film by X-ray photoelectron spectroscopy. TMA diffusions in each polymer were compared with the coordination energies of TMA to each polymer that were calculated by density functional theory (DFT). The diffusions were shown to be inversely correlated to the absolute value of coordination energy.