Analysis Of Cu Research Articles

Investigation of Magnetic Entropy Change and Critical Behavior Analysis of Cu- and Si-Doped Ni–Mn–Sn Heusler Alloys

We have studied the magnetic property as a function of temperature and magnetic field (μ0.H) and critical exponent on Ni–Mn-based Heusler alloys such as Ni46Mn41Sn13 (NMS), Ni46Mn41Sn10Si3 (NMSS), and Ni46Mn38Cu3Sn13 (NMCS). Magneto entropy change and the order of phase transition are estimated around the martensite and austenite phases of all these samples. Magnetic critical behavior of each sample is analyzed around second-order ferromagnetic (FM) austenite phase transition employing Arrott and Kouvel–Fisher plots. The reliability of estimated critical exponents is verified by Widom scaling relation and M3 vs H plot. Furthermore, one more local exponent n which depends on the magnetic state is also estimated through the isothermal magnetization of magnetic entropy change (∆SM) plots of all these samples. The obtained values for all these alloys are well close to the mean-field theoretical model and it is proposed that the existence of long-range magnetic interaction around austenite transition of these materials.

The Binding Ability of a Bicyclic Somatostatin Analogue Towards Cu(II) Ions.

Somatostatin (SST) analogues have aroused the interest of scientists for years. This group of compounds is used in the diagnosis and treatment of neuroendocrine tumors. However, new molecules useful as radiopharmaceuticals in targeted therapy are still searched for. Bicyclic peptides seem to be very interesting in this context. These molecules are associated with beneficial properties. In this work, we present studies on the binding ability of the bicyclic analogue of somatostatin toward Cu(II) ions which could potentially be a chelator for copper radionuclides. The research is focused on the analysis of Cu(II) interactions with the metal binding cycle of the ligand and the influence of the receptor binding site on the coordination process. This is a novelty in comparison to the SST analogues used in medicine, where a metal ion is coordinated by a chelator and connected with a bioactive molecule by the linker. In this work, we present the first coordination study for a bicyclic ligand. The obtained results showed that the complexes with only imidazole donors are characterized by significantly higher stability in comparison to the other peptides.

Heat transfer analysis of Cu–Al2O3 hybrid nanofluid with heat flux and viscous dissipation

Current research explores the influence of Cu–Al2O3 MHD hybrid nanofluid on heat conveyance and flow in a permeable channel with heat flux and viscous dissipation effects. As in hybrid nanofluid, $$\phi_{1}$$ and $$\phi_{2}$$ are used for volume fraction of Cu–Al2O3. We take $$\phi_{1} = 0.2$$ and $$\phi_{2}$$ of different ranges. A Newtonian fluid has been used as a base fluid. Appropriate mathematical modeling has been carried out, and the governing PDEs have been converted into ODEs by applying appropriate similarity transformations. Computations have been performed analytically by exercising homotopy analysis methodology. The influence of several novel parameters on flow fields has been discussed graphically. In addition, plots for skin friction and local Nusselt number for various values of the involved parameters have been drawn to analyze flow and conveyance of heat at the surface. It has been concluded that the fluid’s velocity increases, while the temperature decreases for increasing volume fraction. Temperature of the fluid has opposite behavior for cases of heat source/sink. It has also been found that viscous dissipation enhances the fluid temperature.

Numerical and experimental analysis of Cu–Fe functionally graded beam subjected to tensile loading

Functionally graded materials are new types of composites with heterogeneous microstructure in which some particular physical and mechanical properties change continuously in the thickness direction. In this research, a five-layer copper–iron functionally graded material was fabricated by changing the composition of the layers in a stepwise function between copper and iron using powder metallurgy method. The effect of fabrication process on the microstructure and tensile strength of functionally graded beam was investigated by using two types of presses: uniaxial press and cold iso-static press. Microscopic studies demonstrated appropriate connections between the layers and particles. To achieve ultimate tensile strength and strain, functionally graded copper–iron specimens were tested in tensile loading. The stress–strain graphs obtained from the test showed enhancement in tensile strength of copper and iron functionally graded beam compared to pure copper and iron beams. Finally, a model of this functionally graded material was analysed in ABAQUS finite element code, and the results were verified by experimental tests. Therefore, the present finite element model would be useful to investigate tensile behaviour of functionally graded materials.

Comparative study of mesopourous silica obtained by different synthetic routes to improve the analysis of Cu(II) in sugar cane spirit

Mesoporous silicas have properties that allow their wide chemical application, due to the large amount of silanol groups on their walls. The possibility of introducing functional groups inside and on the surface of their pores becomes viable the use of these functionalized mesoporous materials for the adsorption of metal ions. Cooper ions are essential for vital functions, but in high concentrations, they are responsible for causing problems to the human organism. Therefore, it is important to monitor the species in different media, such as sugar cane spirit. Mesoporous materials type MCM-41 functionalized were obtained by three different methods using direct (in situ) and indirect (post-synthesis) routes. The mesoporous materials have exhibited properties according to the IUPAC classification. Modified carbon paste electrodes (MCPEs) were prepared by immobilizing the synthesized materials for Cu2+ analysis. The modified electrode obtained by the immobilization of functionalized mesoporous R2 (MCPE/R2) presented the best sensitivity for Cu2+ detection. Under optimum experimental conditions, the MCPE/R2 exhibited a linear range in between 0.99 and 11.80 μmol L-1, a sensitivity based on the Limit of Detection (LOD) of 0.50 μmol L-1and Limit of Quantification (LOQ) of 0.99 μmol L-1, precision (DPRmáx) equals to 10.6% and recovery of 92.2%. The developed method proved to be efficient for Cu2+ determination in sugar cane spirit and the accuracy of the results were comparable to those obtained by AAS.

Kinetic analysis of Cu and Zn dissolution from printed circuit board physical processing dust under oxidative ammonia leaching

A very selective leach for an assorted material stream such as the PCB dust is a vital process step to achieve less complex downstream processing. Thermodynamically, oxidative ammonia leaching should complex copper and zinc relatively selectively from the dust compared to other reagents regime, but investigation under optimum kinetic conditions studied and used herein revealed process design realities. For 75–106 μm dust size, 2 M NH4OH, 17.5 M H2O2, 1 atm. Pressure and 400 rpm in a stirred reactor, Cu and Zn recoveries were 92% and 50%, while activation energies evaluated within 283–313 K gave 47.39 kJ/mol and 33.12 kJ/mol under chemical and mixed control reaction mechanisms respectively. Though, Zn(NH3)42+ formation has more negative free energy than Cu(NH3)42+ formation, yet zinc recovery is much lower. The low recovery was attributed to the dust particle morphology with zinc occuring as alloys inert to this reagent condition.

Sonochemical preparation of carbon nanosheets supporting cuprous oxide architecture for high-performance and non-enzymatic electrochemical sensor in biological samples.

Copper (Cu) based metal oxides have high electrocatalytic ability. In this work, we are synthesized stone-like cuprous oxide particles (Cu2O SNPs) covered on acid functionalized graphene oxide (GOS) sheets using ultrasonic process (50kHz and 100W). Besides, the chemical structural and crystalline analyses of Cu2O SNPs@GOS composites were characterized by transmission electron microscopy, X-ray crystallography and energy-dispersive X-ray spectroscopy. The Cu2O SNPs@GOS nanomaterials were tested towards detection of 8-hydroxydeoxyguanosine (8-OHdG) in biological samples. As expected Cu2O SNPs@GOS catalyst modified electrodes performed an outstanding catalytic ability on 8-hydroxydeoxyguanosine oxidation. 8-OHdG is oxidative stress biomarker. Further, it is noted that the detection performance of Cu2O SNPs@GOS coated electrodes and it's highly enhanced due to the synergistic effect of Cu2O SNPs and GOS. Besides, the modified materials provide more electro-active faces and as well as rapid electron transport pathway and shorten diffusion. Moreover, oxidation of 8-OHdG sensor is exploring a long linear or working range of 0.02-1465µM and high sensitivity (8.75nM). The viability of the Cu2O SNPs@GOS proposed electrochemical methods have tested, to find out 8-OHdG concentrations in biological fluids (blood serum and urine) with a satisfying recovery ranges.

Black tea polyphenol theaflavin as promising antioxidant and potential copper chelator.

In this work, we investigated the antioxidant and copper chelating abilities of theaflavin, a polyphenol responsible for astringency, color, and sensation in black tea. Using voltammetric techniques, the analyses were conducted with disposable electrochemical printed carbon chips in conjunction with a portable hand-held potentiostat. Voltammograms of theaflavin showed five separate oxidation peaks, corresponding to the oxidation of five individual functional groups. Electroanalytical data indicated that, after interaction with copper, theaflavin had higher antioxidant potential and was a better copper chelator than epigallocatechin gallate, a major polyphenol present in green tea and a well-known antioxidant. This could be attributed to the extra fused ring and larger number of OH groups in theaflavin. Our findings introduce another natural compound as a potential nutraceutical in oxidation- and copper-modulated illnesses. This simple and fast approach would also be highly pertinent to the inspection of the health benefits of natural food products. To the best of our knowledge, this is the first report of the electrochemical analysis of Cu (II) chelation with theaflavin. © 2020 Society of Chemical Industry.

Application of Dry Biomass of Aphanothece sp. as A Biosorbent of Copper Heavy Metal

Various technologies have been developed to reduce heavy metal content in the wastewater. The biosorption method is a technique that is widely applied because it is cheap, environmentally friendly, and has high efficiency. This study aims to ascertain the potential of dry biomass of microalgae Aphanothece sp. as a biosorbent of Cu (II) ions in synthetic wastewater and determine the appropriate biosorption kinetics model. Analysis of Cu (II) ion concentrations was carried out using Atomic Absorption Spectrophotometer (AAS). The results showed that the optimum conditions for the biosorption process were at pH 4, and the contact time was 210 minutes with the removal efficiency of Cu (II) ions reaching 80.02%. The results of tests on the adsorption isotherm model showed that the biosorption process of Cu (II) ions using dry biomass biosorbent Aphanothece sp. follows the Freundlich isotherm model with an R 2 value of 0.9962.

Heavy Metal Removal from Industrial Wastewater and Runoff Discharge Using Modified Diatomite as Filtration Medium

The adsorption of copper and zinc ions onto the modified diatomite with sodium hydroxide and manganese oxide (Mn-DM) was studied in isotherm batch solutions. The analysis of Cu (II) and Zn (II) results showed the effect of contact time and adsorbent dosage on the adsorption process performed in solutions with individual and combined metal ions, allowing observations of the selectivity and preference of modified diatomite in capturing Cu (II) and Zn (II). The paper also analysed the effect of supplementing peat on the adsorption process, at various ratios to the modified diatomite, to obtain the optimised filter composition with highest adsorption efficiency. The obtained data was used to model the kinetics of the adsorption processes for both metal ions.

基于磁控溅射技术的铜铟镓硒纳米薄膜的LIBS定量分析方法研究

基于磁控溅射技术的铜铟镓硒纳米薄膜的LIBS定量分析方法研究

Second law analysis for mixed convection nanofluid flow in an inclined channel with convectively heated walls

AbstractIn this study, entropy generation analysis for Cu–water nanofluid mixed convective flow in an inclined channel occupied with a saturated porous media with Navier slip and convective boundary conditions is explored. The governing equations composed of equations of velocity and temperature are nondimensionalized and then solved utilizing the technique of homotopy analysis. Temperature and velocity profile expressions are acquired, which are then used to calculate the entropy produced in the scheme. The impacts of the corresponding fluid parameters are addressed in‐depth on velocity, temperature, entropy generation, Bejan number, Nusselt number, skin friction, volume flow rate, and heat carried out by the fluid for nanofluid concentration. Entropy has been observed to be minimal in all cases just above the channel center and maximum at the channel's bottom wall. Fluid friction‐generated entropy has been discovered to have a higher influence on entropy generation. We also provide a comparative study with existing literature to validate our current results.

Stability analysis and multiple solution of Cu–Al2O3/H2O nanofluid contains hybrid nanomaterials over a shrinking surface in the presence of viscous dissipation

Researchers are using different types of nanomaterials for the enhancement of the thermal performance of regular fluids such as water, kerosene oil, etc. However, these days, the researchers are more interested in hybrid nanomaterials. The purpose of this communication is to examine the stability analysis of Cu–Al2O3/water hybrid nanofluid over a non-linear shrinking sheet. The hybrid nanomaterials are composed of Cu and Al2O3. These hybridized nanomaterials are then dissolved in water taken as base fluid to form Cu–Al2O3//water hybrid nanofluid. Mathematical analysis and modeling have been attended in the presence of viscous dissipation and suction/injection effects. The governing equations of mathematical models are transformed into self-similar solutions in the form of ODEs by using similarity transformation. Solutions of the non-linear ODEs are created by employing of three-stage Lobatto IIIa formula which is built-in BVP4C function in the MATLAB software. A comparison of the current study has been done with the preceding published literature. The distributions of velocity, temperature profiles, coefficient of skin friction and heat transfer rate are presented graphically and conferred for numerous significant parameters entering into the problem. Results revealed the existence of dual solutions for a certain range of the suction/blowing parameter. Stability analysis is also done in order to obtain dual solutions stability. The smallest eigenvalues suggest that the first solution is stable from the second solution. Hybrid nanomaterials have a high scope toward nurturing our day-to-day life.

The heavy metal of cuprum (Cu) and lead(Pb) content in Avicennia marina and Rhizophora mucranata

Various types of mangrove plants found in coastal areas have a specific strategy to deal with pollution conditions from heavy metals. One of the several strategies used by mangroves is by accumulating various kinds of heavy metals in various parts of the tree. Most species of mangroves such as Avicennia marina, Rhizophora mucronata, Sonneratia caseolaris, Bruguiera gymnorhyza and others apply this strategy. Avicennia marina and Rhizophora mucronata are pioneer mangrove species that are able to accumulate heavy metals in the roots, stems and leaves. These species are also act as indicator of the sustainability of mangrove ecosystems. The presence of heavy metals will reduce water quality subsequently will decline the overall condition of the ecosystem. How big is the ability of Avicenia marina and Rhizopohora mucronata mangroves to absorb copper (Cu) and Lead (Pb) metals and how the conditions of the aquatic environment surrounding mangroves during heavy metal stress are need to be studied. Analysis of Cu and Pb heavy metals contents were carried out at the Chemistry Laboratory of the USU Medan Pharmacy Faculty. The mangrove species used for the analysis of Cu and Pb heavy metals were A.marina and R. mucronata that grew in Muara Sungai coastal areas from April to August 2018. The results showed heavy metal content of Cu was greater than Pb in wire roots, stems and leaves of A. marina trees. Analysis of roots, leaves and bark of R. mucronata also found greater content of Cu heavy metals than Pb.

Synthesis, Structure, and Properties of Copper(II) Bromide Complexes with N-Disubstituted Thiocarbamoyl-N'-cyclohexylsulfenamides

The [CuLBr2] complexes, where L is RRN–C(=S)–S–NHC6H11 and RR = (C2H5)2, (CH2)5, or (CH2)2O(CH2)2, have been synthesized by reacting equimolar amounts of CuBr2 in methanol and L in diethyl ether. The compounds have been studied by elemental analysis, IR spectroscopy, EPR, X-ray absorption spectroscopy, conductometry, magnetochemistry, and thermal analysis. According to IR spectroscopy data, the ligands in the complexes are bidentately coordinated to Cu(II) through the thione sulfur sulfenamide and nitrogen atoms. Exact structural parameters of the nearest environment of Cu(II) have been determined from analysis of Cu and Br K-edge EXAFS spectra. The Cu–N, Cu–S, and Cu–Br bond lengths are within 2.06–2.08, 2.24–2.49, and 2.33–2.38 A, respectively. The EPR spectra of the complexes in a DMF solution at 293 K are described by the isotropic spin Hamiltonian with spin S = 1/2, including hyperfine coupling to the nuclear spin of the central copper atom and additional hyperfine coupling to the nuclear spins of two equivalent bromine atoms and one nitrogen atom.

Crystal structure, spectroscopic studies, DFT calculations, cyclic voltammetry and biological activity of a copper (II) Schiff base complex

Abstract Herein we describe the chemical synthesis of a novel tetradentate Schiff base ligand (H2L), bridged with a pyridine, and its corresponding mononuclear copper complex (Cu(II)L). H2L, derived from the condensation of 2,3-diaminopyridine and 5-bromosalicylaldehyde, and Cu(II)L were structurally confirmed by routine spectral techniques, UV–Vis, FT-IR, 1H NMR, MS and elemental analysis. Single crystal X-ray diffraction analysis of Cu(II)L complex showed a monoclinic system with P21/C space group and Z = 4 molecules per unit cell. The characterization data of the complex revealed strong coordination via azomethine nitrogen (N) and bromo-phenolate oxygen (O). Moreover, the experimental parameters were found in line with the theoretical parameters. The conductivity measurement showed a non-electrolytic nature of the complex and the electrochemical behavior exhibits two quasi reversible redox processes. In-vitro antimicrobial studies on the synthesized compounds revealed a significant activity of the complex on some bacteria strains than the free ligand. DFT calculations were fully optimized using B3LYP and confirmed practical electrochemical and antibacterial results.

Assessment of copper, iron, zinc and manganese status and speciation in patients with Parkinson’s disease: A pilot study

BackgroundThe objective of this pilot study was to assess iron (Fe), copper (Cu), zinc (Zn), and manganese (Mn) status (hair, serum, and urine) and speciation (serum) in Parkinson’s disease (PD) patients. MethodsA pilot study involving a total of 27 subjects (13 PD patients, 14 controls) was performed. Serum, urine, and hair metal content was assessed using ICP-MS. Speciation analysis of Cu, Zn, Fe, and Mn was performed using a hybrid HPLC-ICP-MS system. ResultsGroup comparisons did not reveal any significant group difference in serum Cu, Zn, Fe, and Mn total metal level between PD patients and controls. Speciation analysis revealed a significant decrease in Cu/ceruloplasmin copper in association with elevation of low-molecular weight species (amino acids)-bound copper. It is proposed that in PD, binding of Cu(II) ions to ceruloplasmin is reduced and free copper ions coordinate with low molecular weight ligands. The level of Mn-albumin complexes in PD patients was more than 4-fold higher as compared to the respective value in the control group. The observed difference may be considered as a marker of redistribution between high and low molecular weight ligands. ConclusionsMetal speciation is significantly affected in serum of PD-patients. These findings are indicative of the potential role of metal metabolism and PD pathogenesis, although the exact mechanisms of such associations require further detailed studies.

Structural analysis of Cu(In,Ga)Se2 thin-films by depth-resolved XAFS

Cu(In,Ga)Se2 (CIGS) is a promising material for thin-film photovoltaic devices. Elucidation of the crystal structure of CIGS thin-films is significant for understanding the properties of CIGS solar cells. This study demonstrates the structural evaluation of CIGS thin-films prepared by a three-stage process using Se K-edge depth-resolved X-ray absorption fine structure (XAFS). The CIGS films changed from a Cu-poor to Cu-rich composition during the second stage of the three-stage process. Notably, Cu2−xSe is generated at the surface of the film at the end of the second stage. After the third stage process, CIGS films have a Cu-poor composition from the surface to a depth of 200 nm. Depth-resolved XAFS technique is sufficiently applicable for evaluation of electronic and crystal structure of CIGS thin-film. This study will provide useful information for the elucidation of the structure of CIGS thin films.

Structure determination of ultra-flat stanene on Cu(111) using low energy electron diffraction

The 2D hexagonal structure of tin atoms which is termed stanene is structurally determined on a Cu(111) substrate using low energy electron diffraction (LEED). The structural analysis of Cu{111}-p(2 × 2)-Sn at a coverage of 0.5 at low temperature reveals the relaxation of underlying Cu atoms, which stabilizes the formation of almost zero-buckled Sn atoms forming a honeycomb structure. Our results using quantitative LEED conclusively reveals an ultra-flat stanene structure that complements well with the previous calculations. The detailed structural analysis presented in this article is expected to give in-depth information for characterizing the properties of as-grown stanene.

Synthesis of sulphonic acid functionalized magnetic mesoporous silica for Cu(II) and Co(II) adsorption

Sulphonic acid functionalized core-shell magnetic mesoporous silica nanoparticles have been synthesized and used for preconcentration and enrichment of Cu(II) and Co(II). Mercapto groups were introduced via co-condensation which were then oxidized by H2O2 to incorporate the sulphonic acid functionality on the silica shell. The higher surface area of the sorbent and magnetic core simplified the extraction process. The adsorption of Cu(II) and Co(II) was achieved in less than 30 min at pH 7. The data showed that the adsorption mechanism followed pseudo-second order rate. The experimental data fits well in Langmuir, Freundlich and Temkin adsorption models. The maximum adsorption capacities for Cu(II) and Co(II) were 132 mg/g and 99.1 mg/g respectively. The newly synthesized material was successfully employed to develop an efficient preconcentarion method prior to the analysis of Cu(II) and Co(II) by graphite furnace atomic absorption spectrometer (GFAAS). The factors affecting the analysis were optimized and interferences from co-existing ions were also investigated. The detection limits for Cu(II) and Co(II) were 20 ng/L and 27 ng/L respectively. The results indicate that the new sorbent can be used for efficient preconcentration of Cu(II) and Co(II) from complex environmental samples.