Low Copper Concentrations Research Articles

Effect of Laser Quenching on Wire–Powder Collaborative Arc Additive Manufacturing of Ti6Al4V-Cu Alloys with 2.4% and 7.9% Copper Content

In this work, Ti6Al4V-Cu alloys with different Cu contents (2.4 and 7.9 wt.%) were fabricated using novel wire–powder synchronous arc additive manufacturing to analyze the effect of laser quenching on Ti6Al4V-Cu alloys. The results show that this method can successfully produce Ti6Al4V-Cu alloys with a uniform composition. As the copper content increased, the alloy transitioned from a Widmanstätten structure to a basketweave structure, and the yield strength and tensile strength of the alloy increased by approximately 35% due to grain refinement and the high volume fraction of Ti2Cu with eutectic lamellae. The microhardness of the alloys significantly increased after laser quenching, particularly for those with low copper contents (from 311 HV to 510 HV). Laser quenching also enhanced the corrosion resistance of the alloy in a 3.5% NaCl solution.

Impact of a Complex Passivating Agent on Heavy Metal Immobilization in Pig Manure and Plant Development

In order to immobilize heavy metals in livestock and poultry manure and promote the safe utilization of pig manure resources, this experiment utilized three types of dried pig manure mixed with soil as raw materials. A combination of biochar and bentonite was established, including treatments with the addition of pig manure (CZ), 2.5% bentonite (F1), 7.5% bentonite (F2), 2.5% biochar (F3), 7.5% biochar (F4), 2.5% biochar + 2.5% bentonite (F5), 2.5% biochar + 7.5% bentonite (F6), 7.5% biochar + 2.5% bentonite (F7), 7.5% biochar + 7.5% bentonite (F8), and with zero addition (CK). After the passivation treatments had been applied, a soybean pot experiment was established to measure various physiological indicators at different soybean development stages. The results revealed that the passivated Cu was predominantly in the reduced and residual states. The passivation rates for F8 in LPS, F7 in MPS, and F8 in HPS were 34.10%, 29.90%, and 39.50%, respectively. Among the three concentrations of a pig manure–soil mixture, the impact of low copper concentration on soybean growth was relatively minimal, whereas medium and high copper concentrations significantly impaired soybean health, resulting in varying degrees of interveinal chlorosis and leaf yellowing from the tip to the base of young leaves, thereby affecting photosynthesis. The combined application of biochar and bentonite enhanced copper passivation and facilitated soybean growth and development.

Efficient removal of low concentrations of copper and lead ions in water using chitosan-condensed tannin composite microspheres

Condensed tannin was solidified onto chitosan microspheres to prepare chitosan-tannin (CT) composite microspheres with a simple preparation method to study its performance in adsorbing copper (Cu2+) and lead ions (Pb2+) in aqueous media. The study investigated the influence of the mass ratio of tannin and chitosan, pH value, adsorption time, and initial concentrations of Cu2+ and Pb2+ on the adsorption capacity of Cu2+ and Pb2+ ions. Additionally, the study examined the adsorption isotherms and kinetics of Cu2+ and Pb2+ on CT composite microspheres. The adsorption process aligns more closely with the fitting results of the Langmuir model. The maximum capacity for saturated monolayer adsorption of CT composite microspheres for Cu2+ and Pb2+ was 37.6 and 52.9 mg/g, respectively. The adsorption process of CT composite microspheres for Cu2+ and Pb2+ was primarily driven by single-layer chemical adsorption. In addition, metal ions adsorbed onto CT composite microspheres can be released by treating them with a dilute solution of strong acid. Furthermore, the CT composite microspheres exhibited impressive removal efficiencies of 82 % and 95 % for Cu2+ and Pb2+ respectively, even at low concentrations of 2 mg/L. The CT composite microspheres have the ability to easily separate the adsorbed Cu2+ and Pb2+ ions.

A low copper content alloy Al(1-x)Cux, x≤0.1: A joint computational and experimental study

Atomistic simulation of Al1-xCux (x ≤ 0.1) alloy is performed and the mechanical properties are calculated within the framework of the density functional theory (DFT) by using of the virtual crystal approximation (VCA). The elastic matrix is calculated within the DFT using the CASTEP code and the dependences of Young's, shear and bulk moduli, Vickers hardness, Poisson's ratio, plasticity coefficient and anisotropy indices on the amount of copper are obtained. Al0.9Cu0.1 alloy was synthesized by spark plasma sintering (SPS) method. As a result, the aluminum and intermetallic CuAl2 phases were identified in the obtained sample by X-ray diffraction patterns. The microstructure (SEM) and Vickers microhardness of the sample were studied. The results of the work compensate for the lack of data for the Al-Cu alloys with a low copper content.

Copper functionalized, pro-angiogenic, and skin regenerative scaffolds based on novel chitosan/APDEMS modified sepiolite-based formulation

Biomaterials-based scaffolds are extensively explored for their proangiogenic and tissue regenerative abilities. The present study aimed to develop wound healing scaffolds based on chitosan/aminopropyldiethoxymethylsilane (APDEMS) modified sepiolite, loaded with copper (0–0.25 g), characterized by FTIR, SEM, mechanical, TGA and analyzed biomedically. The FTIR and SEM confirmed the silane-induced cross-linking and incorporation of copper leading to better dispersion of individual components in the scaffolds. Based on other physicochemical observations, the best scaffold was CS/MS/Cu0.1 (99.5 % increased Young's modulus compared to chitosan, maximum swelling = 900 %, equilibrium time = 70 min); So, CS/MS/Cu0.1 and 0.25 were chosen for further analysis. The CAM assay showed significantly increased angiogenesis in CS/MS/Cu0.1 and 0.25 groups, lacking any developmental anomalies in chick embryos, at lower copper concentrations. The scaffolds' wound healing potential and in-vivo toxicity were assessed by wound excision and histopathology of various organs in mice, respectively. The rate of wound contraction in the CS/MS/Cu0.1 group was significantly (P < 0.05) greater than the control. The abovementioned results corroborated the histological and biochemical findings regarding more collagen deposition in regenerated skin sections and insignificant deviations in biochemical parameters of treated mice, respectively. The formulated biomaterials have proven promising materials for promoting angiogenesis in chick models and accelerating regeneration in mice skin.

The antimicrobial properties of exogenous copper in human synovial fluid against Staphylococcus aureus.

The mechanism by which synovial fluid (SF) kills bacteria has not yet been elucidated, and a better understanding is needed. We sought to analyze the antimicrobial properties of exogenous copper in human SF against Staphylococcus aureus. We performed in vitro growth and viability assays to determine the capability of S. aureus to survive in SF with the addition of 10 µM of copper. We determined the minimum bactericidal concentration of copper (MBC-Cu) and evaluated its sensitivity to killing, comparing wild type (WT) and CopAZB-deficient USA300 strains. UAMS-1 demonstrated a greater sensitivity to SF compared to USA300 WT at 12 hours (p = 0.001) and 24 hours (p = 0.027). UAMS-1 died in statistically significant quantities at 24 hours (p = 0.017), and USA300 WT survived at 24 hours. UAMS-1 was more susceptible to the addition of copper at four (p = 0.001), 12 (p = 0.005), and 24 hours (p = 0.006). We confirmed a high sensitivity to killing with the addition of exogenous copper on both strains at four (p = 0.011), 12 (p = 0.011), and 24 hours (p = 0.011). WT and CopAZB-deficient USA300 strains significantly died in SF, demonstrating a MBC-Cu of 50 µM against USA300 WT (p = 0.011). SF has antimicrobial properties against S. aureus, and UAMS-1 was more sensitive than USA300 WT. Adding 10 µM of copper was highly toxic, confirming its bactericidal effect. We found CopAZB proteins to be involved in copper effluxion by demonstrating the high sensitivity of mutant strains to lower copper concentrations. Thus, we propose CopAZB proteins as potential targets and use exogenous copper as a treatment alternative against S. aureus.

Exploring the strength-concentration relationship of MgCu bioalloys at low copper content using machine learning force fields

Mg-Cu alloy is a prospective biomaterial for orthopedic applications. In physiological environments, the anti-corrosion requirements need MgCu alloys with low copper content but improved strength. Therefore, predicting the “strength-concentration” relationship of MgCu alloys at low copper concentrations is particularly important. However, first-principles calculations and classical molecular dynamics simulations have inherent limitations in dealing with such a problem. We introduce a machine learning force field (MLFF) to explore the strength evolution of low Cu concentration monocrystal/polycrystalline MgCu solid solutions under uniaxial tension. By comparing the lattice constant, phonon spectrum, elastic constant, melting point, and binding energy obtained from first principles calculations, we first verified the accuracy of MgCu MLFF. Then, the simulation results show that when the Cu content is less than 0.43 at%, the ductility and yield strength of MgCu alloy can be simultaneously improved. However, the effect of grain refinement on the strength improvement of MgCu alloys at low copper content is insignificant. This study provides an accurate MLFF field for large-scale mechanical simulation of MgCu alloys and contributes to its rational design for biological applications.

Methanol steam reforming over copper supported on apatites

Low-temperature methanol steam reforming (MSR) over Cu is an efficient process for releasing H2 from this promising liquid hydrogen carrier but the Cu contents of commercial catalysts are often exceedingly high. Here we show that Sr-exchanged fluoro and hydroxyapatites with 1 wt% Cu exhibit very high methanol turnover frequencies up to 386 h−1 and H2 production rates up to 6569 mol H2 kgCu−1 h−1 with CO selectivity as low as ∼0.25 % at 250 °C. Formaldehyde and methyl formate are the only other byproducts which are especially observed over catalysts with low Sr/P ratio in the hydroxyapatite. The reforming proceeds through methoxy, formaldehyde and formate species according to in situ FTIR and mass spectrometric measurements. The spectroscopic analyses further reveal the involvement of apatitic HPO42- ions in the catalytic sequence. Thus, the catalytic synergy between Cu and apatites provides a basis for highly efficient, bifunctional MSR catalysts with low copper content.

Stay with the green: New insights into ancient copper smelting in the Tonglüshan site, China

This paper presents new archaeometallurgical analyses from the Tonglüshan site, a famous ancient mining and smelting site in China. Results show that the primary phases in slag samples from two sites (Sifangtang and Lujia’nao) are all of a vitreous matrix, interspersed with fayalite crystals, wüstite, and hercynite. The trapped metallic particles in the slag are mainly raw copper with few sulfides present, which indicates a direct reduction process of oxidic ore. Iron-rich minerals were likely to be added as flux implied by the few unreacted inclusions in the slag samples. The extremely low copper content in the slag samples demonstrates a high rate of copper recovery, indicating that the copper smelting technology in the region had reached a considerably advanced level. In the meantime, the variations in metal content in slag samples from different periods reveal the diachronic changes in this copper smelting technology. The Tonglüshan site, with its millennia of ancient mining and metallurgical activities, provides an excellent material base for detailed studies on technological evolution.

Application of soil amendments to reduce the transfer of trace metal elements from contaminated soils of Lubumbashi (Democratic Republic of the Congo) to vegetables

The extraction of copper and cobalt from mines has led to the contamination of agricultural soils by trace metal elements (TMEs) (e.g. Cu: 204 to 1355 mg/kg). The mining industry is one of the sources of metal discharges into the environment, contributing to water, soil, and air contamination and causing metabolic disorders in the inhabitants of the city of Lubumbashi (R.D. Congo). This study assessed the effectiveness of organocalcareous soil improvers applied to TME-contaminated soils to reduce their transfer to plants. Following a factorial design, increasing doses of organic soil improvers (chicken droppings and sawdust) and agricultural lime were applied to the soils of three market gardens (high, medium, and low Cu contamination). The experiment was monitored for 60 days. Soil physicochemical properties (pH, TOC, and total and available copper, cobalt, lead, cadmium, and zinc (mg/kg)) were determined for the three gardens and in the vegetable biomass. The daily consumption index of the vegetables was determined based on total TME content. The results show that organocalcareous soil improvers did not promote plant growth and survival on soils with high and medium levels of copper contamination. However, on soils with low copper content, organocalcareous soil improvers improved germination and plant survival and reduced the transfer of metals from the soil to the plants. The best germination and plant survival rates were obtained with the lightly contaminated market garden. In addition, the organo-limestone amendments applied to the soils slightly increased the soil pH from acidic to slightly acidic, with pH values ranging from (5.43 ± 0.07 to 7.26 ± 0.33). The daily vegetable consumption index obtained for cobalt in the low-contaminated garden ranged from (0.029 to 0.465 mg/60 kg/day), i.e. from 0.5 to 8.45 times higher than the FAO/WHO limit, unlike the other trace metals (Cd, Cu and Pb) for which the daily consumption index found was lower than the FAO/WHO limit. Organocalcareous soil improvers can only be applied to soils with low levels of TME contamination, but for soils with medium to high levels of metal contamination, new soilless production techniques such as hydroponics or bioponics are needed.

Effect of Cu content on the microstructure and properties of sintered Fe-0.8C-xCu antifriction materials

Abstract Ferrous antifriction materials (FAMs) play a crucial role in powder metallurgy. Previous studies have primarily focused on exploring the antifriction properties of Fe-C-Cu materials with low copper content (0–5 wt%), while there have been fewer studies on high copper content FAMs. In this study, to investigate the effect of Cu content on the microstructure and properties of sintered FAMs, Fe-0.8C-xCu (x = 5–25 wt%) materials were prepared by powder metallurgy method. The density, microstructure, mechanical performance, friction and wear properties of the samples were analyzed. The results demonstrated a significant change in the relative density, hardness, friction and wear properties of sintered Fe-0.8C-xCu samples with increasing Cu content. Particularly, the Fe-0.8C-15Cu samples exhibited outstanding properties, with a relative density of 77.8%, a hardness of 43 HRB, crushing strength of 380 MPa, an average friction coefficient of 0.21, and a wear rate of 1.36 × 10−8 mm3 N·mm−1. The primary wear mechanisms of the Fe-0.8C-xCu specimens include abrasive wear, adhesion wear, chafing fatigue, pitting, and oxidation. This study aims to provide an experimental and theoretical basis for the development of ferrous antifriction materials suitable for heavy-load conditions.

Investigating the interdependence of microstructure and properties in low-Cu content Al-Zn-Mg alloys via thermodynamic calculation

This paper redesigned the Al-Zn-Mg alloy composition by thermodynamic calculations and experiments, and also explained the precipitation strengthening of the 7xxx alloy. At a Zn/Mg ratio of 3.3–5.3, only the η phase is present. The η phase was experimentally verified as the main contributor to precipitation strengthening. The Al-7.6Zn-2.2Mg-0.2Cu-0.2Cr-0.4Mn-0.15Zr alloy exhibited excellent mechanical properties, with yield and tensile strengths of 510 MPa and 542 MPa under T6 treatment. The low copper content 7xxx alloy designed in this study achieves a yield strength exceeding 500 MPa solely through the compositional design of the Zn/Mg ratio.

Determination of Serum Copper Levels Effect on Learning Ability Among Apparently Healthy Schooling Adolescents Recruited from Sokoto, Nigeria

Copper is vital for human biological system especially for learning functions. The objective of this paper was to determine the effects of serum copper on learning ability among adolescents in Sokoto, Nigeria. Therewith, serum copper concentrations of the 230 recruited adolescents’ in-school from Sokoto, Nigeria were analyzed using the atomic absorption spectroscopy method, and reagents of analytical grade. The investigation of effect of copper concentration on learning potential was done in a quasi-experimental format. The findings (p&lt;0.05) of serum copper concentration revealed mean serum copper in healthy subjects was 211(91.74%); serum copper deficient subjects were 19(8.26%). The low copper concentration observed based on age shows, 13(5.6%) of 14-16 years; and 6(2.6%) of 16-18 years. Observation of copper level in relation to learning potential show a mean of 62.28 in normal participants, and 36.92 in low copper participants. There is need for utmost diverse nutritional intervention on zinc consumption. There are still some adolescents that have low copper level in the state, and it may affect their learning and entire learning. Thus, it is important to provide better nutrition through using disparate intervention methods to bail the situation.

Altering the percolation threshold of PA66‐copper hybrid in an electroless copper deposition process by surface activation of the polymer

AbstractIn this study, the impact of three different principles of surface activation techniques for polyamide fibers on the formation of conductive percolation during the subsequent electroless copper deposition process was investigated. The techniques used are (1) polyamide complexation using a solution mixture of calcium chloride, ethanol and water, (2) atmospheric plasma surface treatment and (3) grafting of 2‐hydroxyethylmethacrylate by radical induced polymerization. As a result, the percolation threshold was shifted to lower copper contents. The copper content required to form conductive structures was reduced ranged between 59% and 89%, depending on the activation techniques. Furthermore, the deposition time was reduced by 37%–57%, resulting in a faster build‐up of the percolation on the fabric. Changes in wetting behavior and substrate surface topography were identified to be the main reasons for these observations. While all applied surface activation techniques led to higher copper contents compared to unmodified reference, the atmospheric plasma modification led to the highest copper contents during the deposition process and a more uniform appearance of the metallised layer.Highlights Three different fiber surface activation methods are evaluated. Fiber surface activation increases wetting and polymer‐metal adhesion. Activated polymer surface leads to faster copper deposition and percolation. Atmospheric plasma modification is the most efficient technique.

Temperature-copper content induced wear mechanism transition in Cu/Ni60A composites

Coppery blast furnace tuyere is easily damaged in high temperature wear environment. Preparing a Ni60A coating by plasma cladding is an effective method to improve its wear resistance and service life. Controlling the appropriate dilution rate is the key to obtain high-quality coatings. The existing research has no clear conclusion on the range of dilution rate of coating for coppery tuyere. In this paper, a series of Cu/Ni60A composites with different copper content (10 wt%, 20 wt%, 40 wt% and 60 wt%) were prepared to mimic Ni60A coatings exhibiting distinct dilution rate. Under the coupling change of temperature and copper content, the wear mechanism of Cu/Ni60A composites showed a complex transition law. Copper content, surface oxide layer (NiO or CuO) and high-temperature softening temperature were the decisive factors of wear transition. The applicable temperatures of Cu/Ni60A composites with low copper content (10 %, 20 %), middle copper content (40 %) and high copper content (60 %) were about 600 °C, 400 °C and 300 °C, respectively. Combined with the heat transfer analysis results, the suitable dilution rates for the coating applied to the inner wall (＜10 %) and front end (10 %-20 %) of tuyere was revealed.

Brain and the whole-body bone imaging appearances in Menkes disease: a case report and literature review

BackgroundMenkes disease (MD) is a rare, inherited, multisystemic copper metabolism disorder. Classical Menkes disease is characterized by low serum copper and ceruloplasmin concentrations, leading to multiple abnormalities in the whole-body, especially in connective tissue and central nervous system. However, serum copper and ceruloplasmin levels are not reliable diagnostic biomarkers due to the low concentrations in healthy newborns either. The featured imaging manifestations play an important role in diagnosing Menkes disease. To our knowledge, there are few reports on the systemic imaging manifestations of Menkes disease.Case presentationA 4-month-old male patient presented with recurrent seizures. He had cognitive, intellectual, growth, gross motor, precision movement, and language developmental lags. The patient’s hemoglobin and serum ceruloplasmin level were low. On MRI, increased intracranial vascular tortuosity, cerebral and cerebellar atrophy, white matter changes, and basal ganglia abnormalities were observed. Plain radiograph revealed wormian bones, rib flaring, metaphyseal spurring, and periosteal reactions in the long bones of the limbs. A pathogenic variant in ATP7A gene was identified in the patient, so he was confirmed the diagnosis of Menkes disease. His symptoms did not improve despite symptomatic and supportive treatment during his hospitalization. Unfortunately, the infant died 3 months after leaving hospital.ConclusionA comprehensive and intuitive understanding of the disease’s imaging manifestations can help clinicians to identify the disease and avoid delays in care.

The Effects of Different Combinations of Cattle Organic Soil Amendments and Copper on Lettuce (cv. Rufus) Plant Growth

In modern agricultural production, cattle manure waste recovery is considered as a sustainable approach to agricultural waste management, reducing environmental pollution and chemical fertilizer use. This study aimed to investigate the effects of manure and digestate derived from a pilot-scale livestock waste-recycling system, in combination with a low copper concentration as a fungicide, on the physiological response of lettuce cv Rufus (Lactuca sativa L.) plants and the associated soil microbiome. A five-week microcosm experiment was conducted in a greenhouse under environmental conditions. Lettuce plant performance was assessed in terms of biomass, leaf area index, photosynthetic activity, chlorophyll measurements, lipid peroxidation, total phenolic content, and nutrient uptake. The results suggested that incorporating digestate into the potting soil mix significantly enhanced crop yields compared to the control and manure treatments. The soil microbial activity increased in the presence of fertilizers, improving the soil chemical and biological properties. The addition of copper negatively affected the growth and physiological performance of the lettuce plants under both the control and manure-treated conditions, except for those grown in the presence of digestate, where copper accumulation was reduced. These findings highlight the potential of growing horticultural crops using organic fertilization through livestock waste anaerobic digestate, establishing a waste-to-food recycling system.

Association between exposure to specific PM2.5 constituents and environment, lifestyle, and clinical parameters in patients with COPD

ABSTRACT This study investigated the correlation between the individual chemical constituents of particulate matter 2.5 μm (PM2.5) and respiratory parameters as well as the living environment and daily behaviors in patients with chronic obstructive pulmonary disease (COPD). Data were obtained from prospective COPD panel conducted in South Korea. Following collection via a microPEM, 18 metallic elements were determined using energy-dispersive X-ray fluorescence spectroscopy. All participants completed detailed questionnaires on living environments and lifestyle practices. Eighty-nine stable COPD patients (mean age 68.1 years; 94.4% male) were analyzed. Several constituents (titanium, aluminum, bromine, and silicone) were significantly associated with respiratory outcomes. Copper and manganese concentrations were significantly associated with the living environment. Increased ventilation time and air purifier operation were associated with lower concentrations of copper, silicone, barium, and titanium. These findings suggest varying relationships between PM2.5 constituents and clinical parameters in COPD patients, providing a basis for personalized interventions and future research.

Study on hardenability of 2050 Al–Cu–Li alloy ultra-thick plate

The hardenability of the 2050 Al–Li alloy ultra-thick plate was evaluated by end quenching and interrupted quench methods. Microstructural investigation at different thickness positions after quenching and aging were conducted using optical microscopy, scanning electron microscope, and transmission electron microscope. The factors affecting the hardenability were discussed in combination with cooling rate and composition examination using energy dispersive spectroscopy. The results indicated that the tensile strength of different thickness positions decreased as the distance from the quenching end increases. Coarse Cu-rich phase particles, formed at the grain and grain boundaries during the end quenching process, lead to solute depletion around the grain boundaries, causing a precipitate-free zone. This zone obstructs the formation of the T1 phase, thereby reducing strength. At identical distances from the quenching end, the tensile strength at the mid-thickness (T/2) location consistently exceeds that at the quarter-thickness (T/4) location. This is due to the original microstructural differences, where the T/2 position experiences a slower cooling rate, has a lower copper content, and shows an increase in the number but a decrease in the size of precipitated coarse Cu-rich phase particles from the supersaturated solution, with the solute consumption remaining relatively constant. Consequently, the tensile strength variation at equal distances from the quenching end is minimal.

Primary Nucleation of Polymorphic α-Synuclein Dimers Depends on Copper Concentrations and Definite Copper-Binding Site.

The primary nucleation process of α-synuclein (AS) that forms toxic oligomeric species is the early stage of the pathological cause of Parkinson's disease. It is well-known that copper influences this primary nucleation process. While significant efforts have been made to solve the structures of polymorphic AS fibrils, the structures of AS oligomers and the copper-bound AS oligomers at the molecular level and the effect of copper concentrations on the primary nucleation are elusive. Here, we propose and demonstrate new molecular mechanism pathways of primary nucleation of AS that are tuned by distinct copper concentrations and by a specific copper-binding site. We present the polymorphic AS dimers bound to different copper-binding sites at the atomic resolution in high- and low-copper concentrations, using extensive molecular dynamics simulations. Our results show the complexity of the primary nucleation pathways that rely on the copper concentrations and the copper binding site. From a broader perspective, our study proposes a new strategy to control the primary nucleation of other toxic amyloid oligomers in other neurodegenerative diseases.