Different Contents Of Cu Research Articles

Deeply revealing the mechanism of the synergistic effect of Cu and P on alleviating CaO poisoning performance of V-W-Ti catalysts in cement kilns

CaO was the inevitable cause of V2O5-WO3-TiO2 catalyst (VWTi) poisoning in cement kilns. The significant reduction in NO conversion was due to the combination of CaO and active species of the vanadium-based catalyst. In this work, the VWTi catalysts were modified with different contents of Cu and P to improve resistance to CaO, thereby extending the service life of catalysts in cement kilns. By doping Cu and P, the Ca-VWCu3P5Ti had better catalytic activity, reduced the poisoning effect of CaO to V5+, thus protecting the redox properties and increasing the surface acidic sites of the catalyst. Meanwhile, the in-situ DRIFTs results showed that the poisoning effect of CaO was weaker on the Ca-VWCu3P5Ti than that of the Ca-VWTi. In addition, the NH3 and NO species could be effectively adsorbed and activated on the surface of the Ca-VWCu3P5Ti by E-R mechanism. In this way, the harm of CaO to the vanadium-based catalysts was effectively reduced. This work provided a promising strategy to design vanadium-based catalysts with superior resistance to CaO in NH3-SCR reaction.

Influence of Cu content on mechanical and tribological properties of Al–7Si–Cu alloy

In this study, Al–7Si–Cu alloys with different contents of Cu were prepared by ultrasonic agitation casting method. The microstructures were characterized by scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS). Dry sliding friction and wear properties with different Cu contents and loads were investigated. The results indicated that the alloy with 3.0 wt% Cu content revealed the optimal microstructure, comprehensive mechanical properties, and tribological properties. The hardness, tensile strength, and yield strength were enhanced by 83%, 57%, and 59%, respectively. The friction coefficient and wear rate reduced by 33% and 24% at 40 N load, respectively. The wear mechanism of Al–7Si–Cu alloy was mainly abrasive wear and delamination wear accompanied by oxidation wear. The improvement of the tribological properties of the alloy was attributed to the combined improvement of the microstructure and mechanical properties.

Mitochondria-mediated apoptosis and endoplasmic reticulum stress are involved in the toxicity induced by copper in the porcine spleen.

Copper (Cu) is one of the common heavy metal pollutants in the environment, and its toxic mechanisms have been extensively studied. However, the immunotoxicity induced by Cu remains rarely reported, and the effects of Cu on endoplasmic reticulum stress and mitochondria-mediated apoptosis have been little studied in the spleen. In this study, pigs were fed with different contents of Cu (10, 125, and 250mg/kg Cu) for 80days to establish a toxicity model. The results showed the Cu exposure triggered endoplasmic reticulum stress in the spleen, as evidenced by increased mRNA and protein levels of GRP94, GRP78, CHOP, XBP1, ATF6, and JNK; the positive rate of GRP78 increased by immunofluorescence analysis. Additionally, mitochondrial fission and fusion homeostasis were disrupted, the expression levels of mitochondrial dynamics-related genes Mfn1, Mfn2, and OPA1 decreased, DRP1 increased, and the positive rate of Mfn1 decreased by immunofluorescence analysis. Furthermore, Cu exposure could induce apoptosis, as demonstrated by the increased expression level of related proteins and genes Bak, Bax, Caspase-3, P53, and Cytc. In conclusion, these results suggest chronic Cu exposure can lead to endoplasmic reticulum stress and imbalance in mitochondrial dynamics and induced apoptosis of pig spleen, and these results provided new insights into the underlying mechanism of Cu exposure caused splenic toxicity, which has public health implications where humans and animals are exposed to copper contamination.

Preparation of PVA/CMC/PVP blended polymer loaded with ZnS1-xCux; investigation of structural and linear/nonlinear optical properties

Nonstoichiometric ZnS1-xCux powders have been loaded to 0.5PVA/0.25CMC/0.25PVP blended polymers using casting method. X-ray diffraction Rietveld analysis was performed for accurate quantification and structural parameters determination of the phases developed in the ZnS1-xCux nanofiller for different content of Cu (x). The surface morphology and chemical composition of the formed polymer blends were investigated using SEM and EDS analysis. The influence of loading the nanofiller with different (x) on the linear and nonlinear optical properties was explored utilizing the UV–vis diffuse reflectance. The variation in the absorption, transmittance, refractive index, extinction coefficient, dielectric constant, energy loss functions, the refractive index dispersion and optical conductivity of the obtained composites was tracked. The determined direct and indirect optical band gap energies of the unloaded blend are 5.16 and 4.92 eV, respectively, which were reduced nonlinearly attaining the lowest values (4.71, 3.5) eV for x = 0.1. The variation in the intensity of fluorescence (FL) and the colors emitted was investigated applying two excitation wavelengths, 317 and 380 nm.

Effects of Long-Term Exposure to Copper on Mitochondria-Mediated Apoptosis in Pig Liver.

Copper (Cu) is listed as one of the main heavy metal pollutants, which poses potential health risks to humans. Excessive intake of Cu has shown toxic effects on the organs of many animals, and the liver is one of the most important organs to metabolize it. In this study, pigs, the mammal with similar metabolic characteristics to humans, were selected to assess the effects of long-term exposure to Cu on mitochondria-mediated apoptosis, which are of great significance for studying the toxicity of Cu to humans. Pigs were fed a diet with different contents of Cu (10, 125, and 250mg/kg) for 80days. Samples of blood and liver tissue were collected on days 40 and 80. Experimental results demonstrated that the accumulation of Cu in the liver was increased in a dose-dependent and time-dependent manner. Meanwhile, the curve of pig's body weight showed that a 125mg/kg Cu diet promoted the growth of pigs during the first 40days and then inhibited it from 40 to 80days, while the 250mg/kg Cu diet inhibited the growth of pigs during 80days of feeding. Additionally, the genes and protein expression levels of Caspase-3, p53, Bax, Bak1, Bid, Bad, CytC, and Drp1 in the treatment group were higher than that in the control group, while Bcl-2, Bcl-xL, Opa1, Mfn1, and Mfn2 were decreased. In conclusion, these results indicated that long-term excessive intake of Cu could inhibit the growth of pigs and induced mitochondria-mediated apoptosis by breaking the mitochondrial dynamic balance. Synopsis: Long-term exposure to high doses of Cu could lead to mitochondrialdysfunction by breaking the mitochondrial dynamic balance, which ultimatelyinduced mitochondria-mediated apoptosis in the liver of pigs. This might be closelyrelated to the growth inhibition and liver damage in pigs.

Metabolomics analysis reveals the effects of copper on mitochondria-mediated apoptosis in kidney of broiler chicken (Gallus gallus)

Copper (Cu) is one of the ubiquitous environmental pollutants which have raised wide concerns about the potential toxic effects and public health threat. For deeply investigating the nephrotoxicity induced by Cu, the effects of Cu on mitochondria-mediated apoptosis in kidney were first to analyze by combining metabolomics and molecular biology techniques. In this study, broiler chicks were fed with different contents of Cu (11, 110, 220, and 330 mg/kg Cu) for 49 d. The results of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining and transmission electron microscope showed that Cu could induce apoptosis in kidney, characterized by the increasing of TUNEL-positive cells and mitochondrial vacuolation. Additionally, a total of 62 differential metabolites were detected by liquid chromatography-mass spectrometry (LC-MS), and mainly enriched in the metabolic pathways including riboflavin metabolism, glutathione metabolism, sphingolipid metabolism, and glycerophospholipid metabolism, which were closely to mitochondrial metabolism. Meanwhile, the decreased mitochondrial membrane potential (MMP), increased mitochondrial membrane permeability and the change of mRNA and protein expression levels associated with mitochondria-mediated apoptosis and mitochondrial dynamics confirmed that Cu could induce mitochondria-mediated apoptosis. Therefore, our results demonstrated that Cu induced mitochondria-mediated apoptosis in kidney. Moreover, this study highlighted the metabolic characteristics of Cu to kidney, which suggested that mitochondrial metabolism could be considered as an important factor influencing toxicity.

Improved corrosive wear resistance of carbidic austempered ductile iron by addition of Cu

In this work, different contents of Cu were added into carbidic austempered ductile iron (CADI) to improve the corrosion resistance and the corrosive wear resistance. Microstructures of CADI have been systematically investigated by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic force microscope (AFM). The results showed that with the addition of Cu elements, the thickness of bainitic ferrite plates and the potential difference (ΔUmatix- graphite nodules and ΔUmatix- carbides) were reduced significantly. The effect of Cu on the corrosion resistance and the corrosive wear resistance has been studied by an electrochemical workstation and two kinds of corrosive wear tester. In addition, worn surfaces and corroded surfaces of the samples have been examined by SEM, 3D laser scanning microscope and X-ray photoelectron spectroscopy (XPS). As the Cu content increased, the corrosion resistance of CADI under acidic condition increased. When the Cu content was 1 wt%, both corrosive wear resistance without load under alkaline condition and corrosive wear resistance with load under alkaline and acidic condition were optimal. Nevertheless, under acidic condition, the corrosive wear resistance without load of CADI with 1.5 wt% Cu was optimal.

Dry reforming of methane over trimetallic NiFeCu alloy catalysts

A series of trimetallic NiFeCu catalysts with different content of Cu were obtained by coprecipitation. We demonstrated the structural evolution of NiFeCu alloy, especially the segregation of Fe, by changing the CH4/CO2 ratio and operating temperature of methane dry reforming. The increment of reaction temperature and content of CH4 in the feed both aggravate Fe segregation and lead to severe carbon deposition on the catalysts. Importantly, Fe in trimetallic catalysts is much more stable than that in bimetallic catalysts.

Fabrication and characterization of Al–Zn–Cu composite coatings with different Cu contents by cold spraying

ABSTRACT This work focus on the effect of different contents of Cu on microstructure and properties of Al–Zn composite coatings. The SEM and EDS were used to analyse the microstructure and composition of the coatings, and the deposition efficiency and porosity of the coating were calculated. The results show that the coatings have low porosity and uniform structure. The hardness, electrical conductivity and corrosion resistance of the coating were measured, and the results showed that the addition of Cu can improve the hardness, electrical conductivity and corrosion resistance of the coating but reduce the deposition efficiency of the powder.

Characterization, conductivity studies, dielectric properties, and gas sensing performance of in situ polymerized polyindole/copper alumina nanocomposites

AbstractConducting polymer composites of polyindole (PIN) and copper–alumina (Cu–Al2O3) nanocomposites were synthesized by in situ polymerization of indole with different contents of Cu–Al2O3 nanoparticles. The polymer nanocomposites were characterized by Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐ray (EDX), transmission electron microscope (TEM), differential scanning calorimetry, thermogravimetric analysis, and ammonia gas sensing performance was also analyzed. FTIR and XRD studies revealed the attachment of Cu–Al2O3 in the molecular chain of PIN. The presence of bright trapezoid channels and variation in morphology for different loading of nanoparticles were confirmed by SEM and TEM. The attachment of Cu–Al2O3 nanoparticles in the PIN matrix was confirmed through EDX spectroscopy. The glass transition temperature and thermal stability of the composites were greatly enhanced with the loading of Cu–Al2O3. Enhancement in alternating current conductivity, dielectric constant and the current–voltage characteristics of the prepared composite revealed the semiconducting nature of the system with an increase in the loading of nanoparticles. Also, nanocomposite exhibited an excellent sensitivity and fast response to ammonia gas. The evaluated result of the present study suggested that Cu–Al2O3 reinforced PIN hybrid is a good candidate for the fabrication of electrochemical devices.

Ni-advanced weathering steels in Maldives for two years: Corrosion results of tropical marine field test

Properties of rust films generated on Ni-advanced weathering steels in a tropical marine environment were investigated by various surface analysis and electrochemical techniques. The results show that corrosion rate of Ni-advanced weathering steels with different contents of Cu exposed for two years in Male Island is much higher than that in the marine atmosphere with lower level of chloride. Cu has no influence on the phase composition of rust films generated on different Ni-advanced weathering steel, but leads to discrepancy of corrosion resistance. Moreover, Ni-advanced weathering steels with different contents of Cu exhibit the combination of uniform corrosion and non-uniform corrosion, higher Cu content can impede the degree of non-uniform corrosion.

Improvement in alkali metal resistance of commercial V2O5–WO3/TiO2 SCR catalysts modified by Ce and Cu

Commercial V2O5–WO3/TiO2 (abbreviated to VWTi) SCR catalysts are modified with Ce and different contents of Cu in wet impregnation method to improve their alkali metals resistance, which is beneficial for prolonging their service life. After K poisoning, NOx conversion of VWCeCuTi sample modified with 0.30% Ce and 0.05% Cu is 89% at 350 °C, which is obviously higher than that of VWTi with a 50% NOx conversion. A series of characterization tests were conducted and verified that the ratio of V5+ and the surface-active oxygen on VWCeCuTi sample increases due to the interaction between V, Ce and Cu. Additionally, with the addition of Ce and Cu, surface acid sites are increased and their stability is strengthened. The enhanced redox property and surface acidity contribute together to the excellent K resistance of VWCeCuTi catalyst.

Effect of Zn on the grain boundary precipitates and resulting alkaline etching of recycled Al-Mg-Si-Cu alloys

The Zinc level in many 6000 Al alloys (Al-Mg-Si-type) was set to a maximum of 0.03 wt% as common industrial practice. Concentrations above 0.03 wt% can modify the alkaline etching mechanism causing the surface to go from a desired smooth look associated with a grain boundary attack (GBA), into an undesired speckled appearance due to preferential grain etching (PGE), visible after anodizing. This significantly limits the ambition of reducing the carbon footprint of Aluminum by increasing the amount of recycled material in the production process. Because Cu has been reported to counteract this negative effect of Zn, the present study is dedicated to contribute to the understanding of this interaction and is focused on Zn and Cu in peak aged AlMgSi alloys. The chemical composition of the various precipitates formed in two Al6063 alloys was studied by means of TEM and EDX, whereby Zn was found in the Q phase (AlMgSiCu) grain boundary precipitates. Two alloys, with different content of Cu and Zn were studied. The Zn/Cu ratio in the bulk was similar for both alloys, but the level of Zn in the Cu containing Q particles in the grain boundaries was different. The increased Zn concentration in Q phase precipitates is believed to decrease the potential of the precipitates with respect to the surrounding matrix. Thus, the Cu/Zn ratio in these alloys is extremely important as it defines the potential differences that in turn cause either GBA or PGE.

Effects of Cu on microstructure and some properties of as-drawn Zn-2Al alloys

The microstructure and some properties of as-drawn Zn-2Al alloys with different content of Cu were investigated by SEM, EDS, XRD and DSC techniques. The results showed that the main phases of Zn-2Al alloys free of Cu were η and α phases. However, the distribution of η and α phases was uneven. The microstructure of Zn-2Al alloys adding Cu became more uniform than those of Zn-2Al alloys and the ε phase (CuZn4) appeared in the alloys containing Cu not less than 2.0 wt%. The content of eutectic component decreased while Cu was added to Zn-2Al alloys. The hardness raised with the increasing of Cu content (0 ∼ 3.0 wt%), while the bending number decreased. It was worthy noting that adding Cu obviously influenced on the corrosion resistance of the Zn-2Al alloys.

Synthesis of Efficient Cu/CoFe2O4 Catalysts for Low Temperature CO Oxidation

Different content of Cu has been loaded onto CoFe2O4 support, and their gas-phase CO oxidation performance has been tested to explore the best Cu loading content and the mechanism of catalyst oxidation. The fundamental characteristics of Cu doped CoFe2O4 are revealed by XRD and TEM. The catalytic mechanism is elucidated by XPS, H2-TPR, CO-TPD and in-situ DRIFTS. The CO oxidation performance is greatly improved upon Cu doping on the surface of CoFe2O4 catalysts. It is found that 5 wt% Cu/CoFe2O4 catalysts showed higher CO oxidation performance.

Impact of Cu Content on Corrosion Property of Zn20Sn Lead- free Solder

By alloying principle, different contents of Cu were added in the matrix Zn20Sn filler metals to form a new type of alloy, the effects of Cu contents on the Zn20Sn solder alloy corrosion resistance were studied. The results show that when the Cu content is less than 4%, with the increase of Cu content, Zn20SnxCu solder alloy corrosion potential increased and corrosion rate reduced gradually, the corrosion resistance of solder alloy increased. When the Cu content is more than 4%, with the increase of Cu content, Zn20SnxCu solder alloy corrosion potential reduced and corrosion rate increased gradually, the corrosion resistance of solder alloy reduced. Main products on the corrosion surface of Zn20SnxCu are Zn5(OH)8Cl2.H2O and ZnO. Under the consideration of the corrosion performance of Zn20SnxCu, the best addition amount of Cu is 4%.

Influence of Cu on the mechanical and tribological properties of Ti3SiC2

Ti3SiC2/Cu composites with different contents of Cu were fabricated by mechanical alloying and spark plasma sintering method. The phase composition and structure of the composites were analyzed by X-ray diffractometry and scanning electron microscopy equipped with energy dispersive spectroscopy. The mechanical and tribological properties of Ti3SiC2/Cu composites were tested and analyzed compared with monolithic Ti3SiC2 in details. The results show that the Cu leads to the decomposition of Ti3SiC2 to produce TiCx, Ti5Si3Cy, Cu3Si, and TiSi2Cz. The friction coefficient and wear rate of the composites are lower than that of monolithic Ti3SiC2, which is ascribed to the fixing effect of hard TiCx, Ti5Si3Cy, and Cu3Si to inhibit the abrasive friction and wear. However, at elevated temperatures (ranging from room temperature to 600°C) the friction and wear of the composites are higher than those at room temperature. Plastic flowing and tribo-oxidation wear accompanied by material transference contribute to the increased friction and wear at elevated temperatures.

Microstructure and crystal growth direction of Al–Cu alloy

The microstructures and crystal growth directions of permanent mould casting (PMC) and directionally solidified (DS) Al–Cu alloys with different contents of Cu were investigated. Simultaneously, the effects of pouring temperature on the microstructure and crystal growth direction of permanent mould casting pure Al were also discussed. The results indicate that the α(Al) crystals in the pure Al do not always keep common columnar grains, but change from the columnar grains to columnar dendrites with developed arms as the pouring temperature rises. The growth direction also varies with the change of pouring temperature. Cu element has similar effects on the microstructures of the PMC and DS casting Al–Cu alloys and the α(Al) crystals gradually change from columnar crystals in turn to columnar dendrites and developed equiaxed dendrites as the Cu content increases. The crystal growth direction in the PMC alloys gradually approaches <110> orientation with increasing Cu content. But the resulting crystals with growth direction of <110> do not belong to feathery grains. There are also no feathery grains to form in all of the DS Al–Cu alloys.

Interface structure and wetting behaviour of Cu/Ti3SiC2 system

Wetting behaviour of a Cu/Ti3SiC2 system was investigated by the sessile drop technique under a vacuum atmosphere. Contact angles between Cu and Ti3SiC2 changed from 95 to 15° as temperatures increased from 1089 to 1270°C. Two distinct reaction layers consisting of different contents of Cu, TiCx, Ti3SiC2 and CuxSiy intermetallics were formed at the interface of Cu and Ti3SiC2. The formation of the interface layers contributes to the improvement of the wettability of the system. The dissolution of Si from theTi3SiC2 into the molten Cu at high temperature plays a dominant role in the wetting behaviour of Cu/Ti3SiC2 systems.

Effect of copper, sulfur, arsenic and antimony on silver distribution in phases of lead blast furnace

An experimental study was carried out to estimate the effect of the lead impurities on the silver distribution in the phases formed in the lead blast furnace. Samples of sinter with different contents of Cu, S, As and Sb were equilibrated under reducing atmosphere (p(CO)/p(CO2)=2.45) at 1573 K in a tube furnace and slowly cooled. The samples were characterized by scanning electron microscopy and microanalysis (SEM-EDS). There were five immiscible phases: slag (CaO, FeO and SiO2), matte (S, Cu and Fe), speiss (As, Fe and Cu), Cu–Sb phase and lead bullion (Pb, Ag, Sb, Cu, etc). The results showed that Cu and Sb promote silver losses during the process since they form a liquid solution with higher silver solubility than liquid bullion. Sulfur and arsenic react with copper to form the matte and speiss phases, respectively. The effect of S and As is to reduce the amount of Cu–Sb alloy and then the silver losses from the bullion.