Fraction Of Copper Research Articles

Determination of total concentration and bioaccessible fraction of metals in tomatoes and their derivatives by MIP OES

This study presents information about the total concentration and bioaccessible fraction of barium (Ba), calcium (Ca), cadmium (Cd), copper (Cu), iron (Fe), mercury (Hg), potassium (K), lithium (Li), magnesium (Mg), manganese (Mn), molybdenum (Mo), lead (Pb) and zinc (Zn) in different cultivars of tomato (Gaucho, Paulista, Italiano and Cherry) and their derivatives (sauce and tomato extract). The determinations were performed by microwave induced plasma optical emission spectrometry (MIP OES). The bioaccessible fraction of the elements was evaluated through in vitro digestion process and the concentrations varied between 25 and 100 % ​for Cu, Fe, Mn and Zn, depending on the type of tomato sample and its derivatives. The total concentrations for all the elements studied were below the recommendation of dietary guidelines. For Ba, only the Italiano sample presented 22 % of bioaccessibility. For Pb, the highest percentage of bioaccessible fraction was found in sauces and tomato extracts. The elements Cd, Hg, Li and Mo presented concentrations lower than the limit of detection for the bioaccessibility method.

Convective flow of a Maxwell hybrid nanofluid due to pressure gradient in a channel

In this work, analytical solution of hybrid Maxwell nanofluid of the vertical channel due to pressure gradient is discussed. By introducing dimensionless variables the governing equations with all levied initial and boundary conditions is converted into dimensionless form. Fractional model for Maxwell fluid is developed by Caputo time fractional differential operator by using the constitutive relation. The dimensionless expression for temperature and velocity are found using Laplace transform. Draw graphs of temperature and velocity by Mathcad software and discuss the behavior of flow parameters and the effect of fractional parameters. As a result, we have found by increasing the volumetric fraction of copper and alumina temperature increases and velocity decreases. Also, fluid flow properties showed dual behavior for small and large time, respectively, by increasing fractional parameters values.

Iron activity measurements and spinel-slag equilibria in alumina-bearing iron silicate slags

Alumina is a common substance deporting in copper smelting slags when various secondary copper fractions, e.g. e-scrap or WEEE, are used as feedstock as such or along with primary sulphide concentrates. Properties of iron-silicate slags at high alumina concentrations, in the iron-alumina spinel saturation, have been studied at 1300 °C by a high temperature equilibration-quenching method combined with EPMA (electron probe microanalysis) phase composition data from the polished sections. The equilibrations were performed in fixed oxygen activity with platinum or palladium powder, which dissolved iron from the slag and generated a heterogeneous equilibrium system, characterised by the general equilibrium criterium in isothermal and isobaric conditions, as.μalloy(Fe) = μslag(Fe) = μspinel(Fe).This criterium was used for measuring experimentally iron activities of molten silicate slags. The locations of the spinel-liquid slag tie-lines were also determined in the oxygen partial pressure range of 10−6–10−10 atm. A comparison with the recent critical thermodynamic assessments of the Fe–O–Al2O3 system indicates that the iron-alumina spinel-corundum phase boundary in silica-containing systems as a function of oxygen partial pressure is too steep and thus the assessed databases do not match with the experimental data of this study. The liquid slag domain from silica to iron oxide saturation is also smaller than expected earlier, as the spinel primary phase boundary locates at higher silica concentrations than e.g. obtained in the assessments of the Mtox database.

Fractions of copper in soil and their contribution to copper availability and uptake in maize–wheat cropping system under Typic hapludalfs

Long-term effects of integrated application of organics and chemical fertilizers on transformation of copper (Cu) into various chemical pools and their availability under maize–wheat cropping system were investigated in the ongoing long-term fertilizer experiment initiated in 1972 at the research farm of Chaudhary Sarwan Kumar Himachal Pradesh Agricultural University on an acidic soil in the Western Himalayas of India. The continuous use of chemical fertilizers alone for 36 years brought about marked depletion in all forms of copper except organically bound Cu (Cu-III) compared to buffer plots. Integrated use of organics and chemical fertilizers gave higher content of Cu forms over chemically treated plots except Cu occluded by free oxides (Cu-IV). Residual Cu was the most dominant form of copper contributing about 62% of the total Cu. Organically bound Cu (Cu-III) was the most important fraction of copper contributing toward DTPA (diethylene triamine pentaacetic acid) extractable Cu. Content of DTPA-extractable Cu increased over control when chemical fertilizers were applied in conjunction with different organics, whereas DTPA-Cu content declined over control with application of chemical fertilizers alone for the last 36 years.

Experimental study of the effect of pressure and laser fluency on laser ablation craters and LIBS emission features of brass sample

We performed measurements on an ablated volume of a brass sample using optical microscopy and spectroscopic analysis of the plasma generated by Nd:YAG laser irradiation. A parametric study was investigated under different gas pressures and laser energy conditions for several time delays in order to determine the laser ablation plume with "ideal" properties. The ablation volume of the brass sample was determined by measuring the volume of the crater after laser ablation. As a result, we have observed that the surrounding gas pressure influences the amount of the ablated material and the expansion dynamics of the plasma plume. The mass fractions of copper, zinc and lead were measured by using CF-LIBS technique. Slight elemental concentration variations, not exceeding 4%, were found when compared with certified values.

Distribution of copper and zinc fractions in a Regosol profile under centenary vineyard

Phytosanitary treatments using Bordeaux mixture or zinc (Zn) fungicides are often used in vineyards, which increase soil copper (Cu) and Zn contents. In this study, the accumulation and distribution of Cu and Zn fractions (water soluble, exchangeable, oxidic, organic and residual fractions) was evaluated along a Regosol profile cultivated with vine since 1890 and treated with Bordeaux mixture. Copper and Zn contents of the superficial layer were around 2000 mg kg−1 and 170 mg kg−1, respectively, and decreased through depth profile. However, accumulation of these metals was also observed in deeper layers of the soil, until 50 cm depth. Most of the total Cu was bound to the mineral fraction, whereas Zn was predominantly in the residual one. In the superficial layer, the desorption potential was 25% for Cu and 46% for Zn of these metals total content. Although the dominance of chemical forms with low geochemical mobility, desorption of Cu and Zn occurs easily, representing a high risk of transference in the environment.

Assay in serum of exchangeable copper and total copper using inductively coupled plasma mass spectrometry (ICP-MS): development, optimisation and evaluation of a routine procedure

The assay in serum of non-caeruloplasmin copper, as exchangeable copper after complexation with EDTA (ExCu) and total copper has been evaluated and compared in patients with varying c-reactive protein(CRP). Measurement of ExCu and total copper, range 0.2–47.2 µmol/L, was developed using ICP-MS. The chelating agents EDTA and TEPA were compared over 0.0–10 g/L after incubation with serum for 60 mins followed by ultrafiltration with Amicon 10 kDa filter. The assay for ExCu was optimised with EDTA 3 g/L (8.1 mmol/L) maintained at pH 7.0–8.0 before ultrafiltration. TEPA was not as selective in chelation of copper. Patients n = 82 were studied in relation to changes in inflammatory marker CRP and a group of patients n = 37 with normal CRP. The ExCu assay gave excellent recoveries (94–102 % but poor recovery for free uncomplexed copper), good repeatability, limit of quantitation 0.19 µmol/l with a provisional reference range 0.48 to 1.63 µmol/L (n = 37 patients). The range for relative exchangeable copper (exchangeable copper divided by total serum copper) was 2.49 to 9.96 %. ExCu was elevated in conditions with increased CRP greater than 100 mg/L suggesting an effect of inflammation on the free copper fraction. A reliable and reproducible assay for ExCu and total copper has been developed. The upregulated inflammatory state increases the ExCu suggesting excess free copper.

Fractionation and mobility of copper, cadmium, and lead in some soil irrigated with sewage water in Qena governorate, upper Egypt

This study was conducted to investigate the chemical fractionation and mobility of Cu, Cd and Pb in some soil irrigated with sewage water in Qena governorate, Upper Egypt. Sequential extraction results showed that in the treated soil, a major proportion of Cu, Pb, and Cd was associated with poorly crystalline iron oxide bound (PCFeOX), crystalline iron oxide – occluded (CFeOX) and a major proportion of Cu, Pb and Cd was associated with residual (RES) fractions. Based on relative percent. the results also show that The non-labile Cu, Cd and Pb in the non-irrigated soil partially transformed to the potentially labile Cu due to the irrigation with sewage water Also, a part of the readily labile and potentially labile Cu, Cd and Pb of the sewage water irrigated soils for short time transformed to the non-labile fraction with irrigation with same water for a long time. Higher mobility of metals in the soils irrigated with sewage water for short time represent a potential hazard for the redistribution and translocation of these metals into the food chain and leach to ground water.

Simplified measures of copper fractions in wine: colorimetric and filtration‐based approaches

Background and Aims Simple methods for determining Cu forms in wine do not currently exist. This study demonstrates the relevance of measuring a specific fraction of Cu in wine, and introduces simplified methods for its measurement utilising either colorimetry, or filtration in combination with routine measures of total Cu in wine. Methods and Results Electrochemically detectable Cu provided a threshold level of Cu that related directly to the accumulation of free hydrogen sulfide and free methanethiol in bottled wines. A simple colorimetric method using bicinchoninic acid was optimised to allow a rapid approximation of this fraction of Cu in white wine. By modification of the measurement conditions, an extra fraction of Cu associated with the partial release of Cu from thiols could also be quantified. The use of diatomaceous earth depth filters to isolate these fractions of Cu was also assessed. After passing red wine through the filters, the concentration of Cu in the filtrate correlated well with the electrochemically detectable Cu. Alternatively, for white wine the concentration of filtrate Cu overestimated this fraction of Cu and this was attributed to its inability to distinguish sulfhydryl-free Cu from Cu loosely bound to thiols. Conclusions Multiple and simplified approaches have been devised to allow measurement of Cu fractions in wine. Significance of the Study These methodologies will allow an important fraction of Cu in wine to be measured with a spectrophotometer.

Uptake of trace elements and isotope fractionation of Cu and Zn by birch (Betula pendula) growing on mineralized coal waste pile

Aims of the present study were to determine the extent of the uptake of selected trace elements by birch (Betula pendula Roth) growing on the partly burnt coal waste pile and to evaluate isotopic fractionation of copper (Cu) zinc (Zn). Substrates, birch sap and leaves were collected in the coal waste pile and in a reference area outside the waste pile. The concentration of trace elements in birch sap and leaves both in birch growing on the coal waste pile and at reference sites increase in the range of U, As, Se > Cd, Mo, Cu > Pb > Ba ≫ Zn. However, the uptake of elements by birch is restricted when concentration of metals in substrates are too high.Compared to the isotopic composition of Cu in waste substrates and soils (δ65Cu = – 0.93 to + 1.49‰), this element in sap and leaves (δ65Cu = – 0.58 to −1.64 and – 0.59 to – 2.35‰, respectively) is depleted in heavy isotope regardless of plant-available concentration of Cu in substrates. Compared to the isotopic composition of Zn in substrates (δ66Zn = – 0.20 to 1.43‰), its isotopic composition in sap and leaves (δ66Zn = – 0.85 to + 1.00 and – 0.21 to + 0.57‰, respectively) is depleted in the heavy isotope only when the plant-available concentration of Zn in the substrate and soil is high (>20 mg kg−1). At low plant-available concentration of Zn no isotopic fractionation or enrichment of Zn in the heavy isotope was recorded.

Effect of land-use types on edaphic properties and plant species diversity in Mediterranean agroecosystem.

Land-use intensification, contrary to sustainable land management, has an impact on the healthiness of the environmental agroecosystem. To assess the environmental implications in abandoned land, olive groves and maize crops, the most sensitive and reliable edaphic indicators were measured to estimate plant species diversity and potentially toxic elements in soil, among different types of land-use. Species diversity presents a decrease in maize crops and olive groves compared to abandoned land. The families with the greatest species diversity were Poaceae, Asteraceae and Fabaceae in each land-use. From the results of the canonical correspondence analysis among species, sampling sites and selected environmental variables, a clear separation between species and sampling sites belonging to different types of land-use was found, presenting strong correlation with specific edaphic parameters (pH, Soil Organic Matter, Silt, Electrical Conductivity, Total Nitrogen, , P, K, Zn and Cu). Species diversity was reduced in maize crops due to anthropogenic interventions such as the excessive use of nitrogen and phosphate fertilizers and herbicides. Despite the fact that the lowest richness of plant species was found in olive groves, non-removal of crop residue preserves soil organic matter. In 7.4% of soil samples in olive groves, concentrations were over 100 mg kg−1 denoting polluted soils, while the potentially toxic concentrations of bioavailable copper fraction ( probably lead to a decrease of species diversity. Future researches should therefore focus on the accumulation of toxic elements in agricultural land to preserve species diversity and a healthy environment.

Contaminated soil amendment by diatomite: chemical fractions of zinc, lead, copper and cadmium

High concentration of labile metals in soil directly affects soil quality, water health and human safety. Decreasing mobility of metals, especially in contaminated soils, by cost-effective amendments may alleviate environmental problems. Natural diatomite was investigated to immobilize toxic elements of zinc, lead, copper and cadmium in a contaminated calcareous soil. The diatomite was characterized using X-ray fluorescence spectrometry and scanning electron microscopy. Contaminated soil was incubated with 0, 2 and 5 weight -% of diatomite at 25 °C for 8 weeks. Tessier sequential extraction method was also used as a suitable method for identification of chemical forms of heavy metals; metal stability index and mobility factor were calculated. Results showed that application of diatomite in soil significantly decreased the metals in the exchangeable fraction and increased them in the residual fraction. The exchangeable metal fractions decreased by 66–88%, and residual fractions increased by 18–94% in the 5 weight -% of diatomite treatment after 8-week incubation. With an increase in the amount of diatomite applied and the incubation time, metal mobility factor values significantly decreased and soil pH values increased. Application of diatomite caused the heavy metals redistribution toward more stable forms and leads to an increase in stability index values. In conclusion, in situ immobilization of heavy metals by application of diatomite, as a low-cost amendment, had a significant potential to stabilize metals in the contaminated calcareous soil.

Modelling the spatial variability of soil micronutrients for site specific nutrient management in a semi-arid tropical environment

Deficiency of micronutrients in the soils of semi-arid tropical (SAT) environments is a major limiting factor for crop production. This study aims to model the spatial variability of soil micronutrients in croplands of Thimmajipet block, Mahabubnagar, Telangana, India. We collected 1508 georeferenced surface (0–15 cm) soil samples at a grid interval of 325 × 325 m and analysed them for DTPA extractable fractions of iron (Fe), manganese (Mn), copper (Cu), zinc (Zn) and boron (B). Landform and topographic variables were derived from the digital elevation model of the study area. Results showed that all the micronutrients varied highly (CV > 35%) in the order of Zn > Fe > Cu > B > Mn. The Q–Q plots indicated non-normal frequency distribution for all the micronutrients, and log transformation improved them. We compared spherical, circular, exponential, and Gaussian models of ordinary kriging interpolation to define the spatial variability structure. The spherical model with the lowest RMSE and better r2 values was selected to map the spatial distribution of the micronutrients. The nugget to sill ratio (N:S > 0.75) indicated that the micronutrients were weakly spatial dependent. Multiple regression analysis (p < 0.05) indicated that the micronutrient concentration and spatial distribution were controlled by (1) parent material; (2) CaCO3; (3) OC; and (4) antagonistic nutrient interaction. Further, critical deficiency zones of Zn, Cu, B and Fe were delineated by integrating cadastral map on the spatial distribution maps. Our study demonstrates that the large scale spatial variability mapping of soil micronutrients is a prerequisite for implementing site-specific nutrient management in the SAT regions.

Influence of Copper Additives on Heat Capacity and Thermodynamic Functions of A7E Brand Aluminum

The economic feasibility of applying aluminum as a conductor is explained by the favorable ratio of its cost (which has remained almost constant for many years) to the cost of copper. When using conducting aluminum alloys to fabricate thin wire, winding wire, etc., some difficulties can appear in connection with their insufficient strength and small number of kinks before fracture. In recent years, aluminum alloys have been developed which possess strength characteristics, making it possible to apply them as conductors even in the soft state. One promising consumer of aluminum is the electrotechnical industry. From here, the development of new compositions of alloys based on this metal is very urgent. The temperature dependence of the heat capacity of A7E aluminum alloys with copper is determined experimentally and the variations in their thermodynamic functions are calculated. Investigations are carried out using computers and the Sigma Plot program. Polynomials of the temperature dependence of the heat capacity and variations in thermodynamic functions (enthalpy, entropy, and Gibbs energy) of these alloys and a reference alloy (Al of the A5N brand), which have the correlation coefficient Rcorr = 0.992–0.998, are established. It is shown that heat capacity of A7E brand aluminum decreases with an increase in the copper content and increases with an increase in temperature. The enthalpy and entropy of alloys of A7 brand aluminum with copper increase with an increase in the copper fraction and decrease with an increase in temperature. The inverse dependence is characteristic of the Gibbs energy.

Method for determination of thermophysical properties of polymer composite materials

The paper presents the results of studies of thermophysical properties: heat capacity, thermal conductivity, thermal diffusivity and heat storage ability of polymeric polymer composite materials. A method is proposed for determining these properties, based on the well-known method for determining thermophysical properties by eliminating variables. The experimental values of the thermophysical properties of polymer composite materials with the addition of powder particles of various fractions of aluminium, iron, carbon and copper are obtained. The effectiveness of the proposed method is shown by comparing the known values of the specific heat and thermal conductivity of polyurethane with experimental.

XAS analysis of copper binding in soils

Ecological distribution of copper from soil is depended on its bioavailability and mobility. Copper binding on heterogeneous soil composition is a key information for understanding the long-term fate benefiting suitable management practice for copper in the environment. X-ray absorption spectroscopy (XAS) techniques were used to provide microscopic scale information of copper-binding on different soils. Soil samples containing 14.9-56.6% clay and 0.5-3.4% organic matter were studied. Dry-powder soil samples containing approximated 0.3% copper from batch equilibrated equilibrium experiments were analyzed. Copper K-edge spectrum were collected at the Synchrotron light research institute (SLRI), Thailand in X-ray absorption near edge structure (XANES) and Extended x-ray absorption fine structure (EXAFS) spectrum region. Linear combination fit (LCF) analysis of XANES spectrum resulted the phase fraction of copper were copper acetate (55-79%) and copper sulfate (9-46%) in all soils, while, copper hydroxide (24%) was exhibited in siliceous coarse-texture soil. EXAFS analysis using copper acetated model structure found four oxygen surrounded copper atom at 1.91-1.974 Ã… in the first shell which positioned in the equatorial plane of a Jahn-Teller distorted octahedral without the existing of weak binding of two axial oxygen atom. Carbon atoms presented in the second shell at 2.73-2.91 Ã… and its coordination number related to soil organic matter content. XANES and EXAFS studied on copper binding in soils result that the predominant copper in soil is in organic matter complex via carboxyl functional group and sulfated ligand. Copper-C binding occurred in local structure which corresponded to soil organic matter content.

Preliminary Design of DEMO PF Coils Based on EU DEMO 2018 Baseline

The dimensioning of Winding Packs and allocation of materials in DEMO PF coils is proposed based on the requirements defined by the EUROfusion 2018 DEMO baseline. The coils are pancake-wound and use two types of forced flow cable-in-conduit conductors. The conductor which uses NbTi has a high void fraction but has no separated low-impedance cooling channel. On the other hand, the conductor made using Nb3Sn has a separated low-impedance cooling channel and therefore low void fraction in the remaining cable space. Both the conductors have a rectangular cross-section. The design addresses the dimensioning of the Winding Pack (WP) based on the electromagnetic field calculations and stress analysis. The amount of superconductor, copper, and cable void fraction in the conductor are determined by the coil current, magnetic field and assumed temperature margin. The amount of structural material in the conductor jacket depends mainly on the fatigue stress corresponding to the pulsed operation of these coils. For PF1 and PF6 coils, the comparison of NbTi and Nb3Sn design options suggest a more efficient allocation of structural and superconducting material in the latter case. The WP dimensions do not significantly depend on the winding technique (pancake vs layer winding).

Optimization and sensitivity analysis of heat transport of hybrid nanoliquid in an annulus with quadratic Boussinesq approximation and quadratic thermal radiation

The quadratic convective flow of hybrid nanoliquid in an annulus subjected to quadratic thermal radiation is studied for the first time. The impact of suction/injection and the uniform movement of the rings are considered. Nonlinear equations are handled numerically by adopting the shooting technique. An optimization procedure is performed by using response surface methodology. The maximum heat transport is observed for chosen values of effective parameters (thermal radiation parameter $$ (5 \le Rt \le 15) $$ , temperature ratio parameter $$ (1.1 \le \theta_{w} \le 5.1) $$ and nanoparticle volume fraction of copper $$ (1\% \le \phi_{\text{Cu}} \le 3\% )) $$ at three different levels (low(− 1), middle(0) and high(+ 1)). In addition, a slope of the data point is evaluated for the friction coefficient and the Nusselt number. The results showed that the impact of quadratic thermal radiation on velocity and temperature distributions is more significant than linear thermal radiation. Further, an increase in quadratic convection and quadratic thermal radiation leads to an improvement in the friction coefficient of the skin on the inner surface of the outer annulus. Furthermore, the sensitivity of the friction coefficient is positive for the appearance of quadratic thermal radiation.

Flow and heat transfer of a hybrid nanofluid past a permeable moving surface

A steady flow and heat transfer of a hybrid nanofluid past a permeable moving surface is investigated. In this study, 0.1 solid volume fraction of alumina (Al2O3) is fixed, then consequently, various solid volume fractions of copper (Cu) are added into the mixture with water as the base fluid to form Cu-Al2O3/water hybrid nanofluid. The similarity equations are obtained by converting the governing equations of the hybrid nanofluid using the technique of similarity transformation. The bvp4c function available in Matlab software is used to solve the similarity equations numerically. The numerical results are obtained for selected parameters and discussed in detail. It is found that hybrid nanofluid enhances the heat transfer rate compared to the regular nanofluid. The results show that two solutions exist up to a certain value of the moving parameter and suction strengths. The critical value in which the solution is in existence decreases as nanoparticle volume fractions increase. The temporal stability analysis is conducted in determining the stability of the dual solutions, and it is revealed that only one of them is stable and physically reliable.

Fabrication of TiC from the Cu–Ti–C system under the super-gravity field

Abstract An innovative approach of fabricating fine TiC particles through the dissolution of solid carbon in the CuxTi melt and subsequently separation with super-gravity is proposed in this study. The reactant mixtures of titanium sponge, copper and carbon particles reacted at 1573 K for 4 h and then the near-spheroidal TiC grains gradually precipitated out of the Cu–Ti–C system. The influences of copper content, separating temperature, gravity coefficient and separating time on the separation of precipitated TiC from the Cu–Ti–C melt have been studied. The particle size distribution and stoichiometric of TiC were calculated, and the detailed mechanism of fabricating TiC was discussed. The experimental results showed that the mass fraction of copper mixed with TiC in the residue was 6.5 wt% and the yield of the copper-rich phase exceeded 89 wt% under super-gravity treatment with the conditions of χCu = 90 wt%, T = 1523 K, t = 120 s and G = 600. After leaching with the sulfuric acid solution, the purity of TiC particulates was 99 wt% and the removal rate of the copper impurity could be up to 97.8%. Finally, the product of the homogeneous and fine TiC particles with good dispersibility was obtained. The circle equivalent diameter and the median diameter of the TiC particulates were found to be 2.09 μm and 2.12 μm, respectively. The elongation and the aspect ratio of the TiC particulates were 83.4% and 74.4%, respectively. Moreover, the lattice parameter of the purified TiC particulates was calculated by the Nelson-Riley extrapolation function which was near to the standard value, and the stoichiometry of TiC particulates obtained in this work was close to 1.