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Sample records for cr cu cd

  1. Electronic, Magnetic, and Redox Properties of [MFe(3)S(4)] Clusters (M = Cd, Cu, Cr) in Pyrococcus furiosus Ferredoxin.

    Science.gov (United States)

    Staples, Christopher R.; Dhawan, Ish K.; Finnegan, Michael G.; Dwinell, Derek A.; Zhou, Zhi Hao; Huang, Heshu; Verhagen, Marc F. J. M.; Adams, Michael W. W.; Johnson, Michael K.

    1997-12-03

    The ground- and excited-state properties of heterometallic [CuFe(3)S(4)](2+,+), [CdFe(3)S(4)](2+,+), and [CrFe(3)S(4)](2+,+) cubane clusters assembled in Pyrococcus furiosus ferredoxin have been investigated by the combination of EPR and variable-temperature/variable-field magnetic circular dichroism (MCD) studies. The results indicate Cd(2+) incorporation into [Fe(3)S(4)](0,-) cluster fragments to yield S = 2 [CdFe(3)S(4)](2+) and S = (5)/(2) [CdFe(3)S(4)](+) clusters and Cu(+) incorporation into [Fe(3)S(4)](+,0) cluster fragments to yield S = (1)/(2) [CuFe(3)S(4)](2+) and S = 2 [CuFe(3)S(4)](+) clusters. This is the first report of the preparation of cubane type [CrFe(3)S(4)](2+,+) clusters, and the combination of EPR and MCD results indicates S = 0 and S = (3)/(2) ground states for the oxidized and reduced forms, respectively. Midpoint potentials for the [CdFe(3)S(4)](2+,+), [CrFe(3)S(4)](2+,+), and [CuFe(3)S(4)](2+,+) couples, E(m) = -470 +/- 15, -440 +/- 10, and +190 +/- 10 mV (vs NHE), respectively, were determined by EPR-monitored redox titrations or direct electrochemistry at a glassy carbon electrode. The trends in redox potential, ground-state spin, and electron delocalization of [MFe(3)S(4)](2+,+) clusters in P. furiosus ferredoxin are discussed as a function of heterometal (M = Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Tl).

  2. Determination of Cu, Cd, Pb and Cr in yogurt by slurry sampling electrothermal atomic absorption spectrometry: A case study for Brazilian yogurt.

    Science.gov (United States)

    de Andrade, Camila Kulek; de Brito, Patrícia Micaella Klack; Dos Anjos, Vanessa Egéa; Quináia, Sueli Pércio

    2018-02-01

    A slurry sampling electrothermal atomic absorption spectrometric method is proposed for the determination of trace elements such as Cu, Cr, Cd and Pb in yogurt. The main factors affecting the slurry preparation were optimized: nature and concentration of acid solution and sonication time. The analytical method was validated in-house by calibration, linearity, limits of detection and quantification, precision and accuracy test obtaining satisfactory results in all cases. The proposed method was applied for the determination of Cd, Cr, Cu and Pb in some Brazilian yogurt samples. For these samples, the concentrations ranged from 2.5±0.2 to 12.4±0.2ngg -1 ; 34±3 to 899±7ngg -1 ; <8.3 to 12±1ngg -1 ; and <35.4 to 210±16ngg -1 for Cd, Cu, Cr and Pb, respectively. The daily intake of Cd, Cu, Cr and Pb via consumption of these samples was estimated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Electrothermal vaporization inductively coupled plasma-mass spectrometry for the determination of Cr, Cu, Cd, Hg and Pb in rice flour

    International Nuclear Information System (INIS)

    Li, P.-C.; Jiang, S.-J.

    2003-01-01

    Ultrasonic slurry sampling (USS)-electrothermal vaporization (ETV) dynamic reaction cell TM (DRC) inductively coupled plasma-mass spectrometry (ICP-MS) has been applied to determine Cr, Cu, Cd, Hg and Pb in rice samples. The influences of instrument operating conditions and slurry preparation on the ion signals were reported. Ascorbic acid was used as a modifier to enhance the ion signals. The background ions at the chromium masses were reduced in intensity significantly by using 0.4 ml min -1 NH 3 as reaction cell gas in the dynamic reaction cell while a q value of 0.6 was used. Since the sensitivities of Cr, Cu, Cd, Hg and Pb in rice flour slurry and aqueous solution were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Cu, Cd, Hg and Pb in these rice samples. This method has been applied to the determination of Cr, Cu, Cd, Hg and Pb in NIST SRM 1568a rice flour reference material and two rice samples purchased from the market. The analytical results for the reference material agreed with the certified values. The results for the rice samples for which no reference values were available were also found to be in good agreement between the isotope dilution and standard addition methods. The method's detection limits estimated from the standard addition plots were about 0.44, 1.7, 0.4, 0.53 and 0.69 ng g -1 for Cr, Cu, Cd, Hg and Pb, respectively, in the original rice flour

  4. Batch adsorption of heavy metals (Cu, Pb, Fe, Cr and Cd) from ...

    African Journals Online (AJOL)

    cinthia

    This study was carried out to evaluate the efficiency of metals (Cu, Fe, Pb, Cr and Cd) removal from mixed metal ions solution using coconut husk as adsorbent. The effects of varying contact time, initial metal ion concentration, adsorbent dose and pH on adsorption process of these metals were studied using synthetically ...

  5. Visible light CrO{sub 4}{sup 2-} reduction using the new CuAlO{sub 2}/CdS hetero-system

    Energy Technology Data Exchange (ETDEWEB)

    Brahimi, R. [Centre of Research in Physical and Chemical Analysis (CRAPC), BP 248, RP 16004 Algiers (Algeria); Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry (USTHB), BP 32 16111 Algiers (Algeria); Bessekhouad, Y. [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry (USTHB), BP 32 16111 Algiers (Algeria); National Veterinary High School, BP 16111 Algiers (Algeria); Nasrallah, N. [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry (USTHB), BP 32 16111 Algiers (Algeria); Trari, M., E-mail: solarchemistry@gmail.com [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry (USTHB), BP 32 16111 Algiers (Algeria)

    2012-06-15

    Graphical abstract: Pseudo-first order kinetic for CrO{sub 4}{sup 2-} photoreduction for various concentrations. Highlights: Black-Right-Pointing-Pointer The work deals with the chromium reduction over CuAlO{sub 2}/CdS hetero-system. Black-Right-Pointing-Pointer The conduction band of CdS (-1.08 V) is more negative than the CrO{sub 4}{sup 2-}/Cr{sup 3+} level. Black-Right-Pointing-Pointer The sensitizer CuAlO{sub 2} has been synthesized by sol-gel. Black-Right-Pointing-Pointer The Cr(VI) reduction follows a pseudo first order kinetic with of salicylic acid. - Abstract: In this study, 64% of hexavalent chromium Cr(VI) reduction from the initial concentration (10{sup -4} M) is reported under visible light using the (CuAlO{sub 2}/CdS) hetero-system. In this new hetero-system, low doped CuAlO{sub 2} delafossite, synthesized by sol-gel works as an electrons reservoir with a wide space charge region (440 nm). In this case, the electron transfer to chromate is mediated via the hexagonal CdS variety, whose conduction band level is at -1.08 V with respect to the saturated calomel electrode which is more negative than the CrO{sub 4}{sup 2-}/Cr{sup 3+} level. This high reduction rate is achieved under optimized pH and CuAlO{sub 2} percentage. Moreover, salicylic acid gives the best performance among hole scavengers and CuAlO{sub 2} approaches 100% photostability at pH 7.5. The photo-catalytic process follows a pseudo first order kinetic with a half life of 2 h. The reaction products are identified by UV-visible spectrophotometry and linear voltametry at a platinum rotating electrode. The results reveal the presence of Cr{sup 3+} after irradiation.

  6. Determination of As, Cd, Cr, Cu, Hg, Sb and Se concentrations by radiochemical neutron activation analysis in different Brazilian regional diets

    International Nuclear Information System (INIS)

    Favaro, D.I.T.; Maihara, V.A.; Armelin, M.J.A.; Vasconcellos, M.B.A.; Cozzolino, S.M.

    1994-01-01

    Radiochemical separation procedures developed for the determination of seven elements: As, Cd, Cr, Cu, Hg, Sb and Se in different Brazilian regional diets are described. In the case of the elements As, Hg, Sb and Se, the procedure was based on retention in inorganic exchanger TFO (tin dioxide) and determination of Hg by extraction with Ni(DDC) 2 . For determination of Cd, Cr, Cu and Se the procedure chosen was based on retention in inorganic exchanger HMD (hydrated manganese dioxide) and extraction of Cu and Cd as diethyldithiocarbamate compounds. The accuracy and precision of the methods studied were tested by means of analyses of different reference materials-Due to the lack of data on trace element levels in Brazilian foodstuffs and diets, these methods were applied to determination of these elements in different Brazilian regional diets. These s were supplied by the Food and Experimental Nutrition Department of the Faculty of Pharmaceutical Science, University of Sao Paulo. The daily intake values for these diets are presented for As, Cd, Cr, Cu, Hg, Sb and Se. (author) 21 refs.; 6 tabs

  7. pH dependence of sorption of Cd 2+ , Zn 2+ , Cu 2+ and Cr 3+ on ...

    African Journals Online (AJOL)

    pH dependence of sorption of Cd 2+ , Zn 2+ , Cu 2+ and Cr 3+ on crude water and sodium chloride extracts of Moringa stenopetala and Moringa oleifera,/i> ... characterization of the actual powder by proton nuclear magnetic resonance showed clear presence of amide (-CO-N-H), benzenoid (Ar-H), saturated alkyl and ...

  8. Soil Cd, Cr, Cu, Ni, Pb and Zn sorption and retention models using SVM: Variable selection and competitive model.

    Science.gov (United States)

    González Costa, J J; Reigosa, M J; Matías, J M; Covelo, E F

    2017-09-01

    The aim of this study was to model the sorption and retention of Cd, Cu, Ni, Pb and Zn in soils. To that extent, the sorption and retention of these metals were studied and the soil characterization was performed separately. Multiple stepwise regression was used to produce multivariate models with linear techniques and with support vector machines, all of which included 15 explanatory variables characterizing soils. When the R-squared values are represented, two different groups are noticed. Cr, Cu and Pb sorption and retention show a higher R-squared; the most explanatory variables being humified organic matter, Al oxides and, in some cases, cation-exchange capacity (CEC). The other group of metals (Cd, Ni and Zn) shows a lower R-squared, and clays are the most explanatory variables, including a percentage of vermiculite and slime. In some cases, quartz, plagioclase or hematite percentages also show some explanatory capacity. Support Vector Machine (SVM) regression shows that the different models are not as regular as in multiple regression in terms of number of variables, the regression for nickel adsorption being the one with the highest number of variables in its optimal model. On the other hand, there are cases where the most explanatory variables are the same for two metals, as it happens with Cd and Cr adsorption. A similar adsorption mechanism is thus postulated. These patterns of the introduction of variables in the model allow us to create explainability sequences. Those which are the most similar to the selectivity sequences obtained by Covelo (2005) are Mn oxides in multiple regression and change capacity in SVM. Among all the variables, the only one that is explanatory for all the metals after applying the maximum parsimony principle is the percentage of sand in the retention process. In the competitive model arising from the aforementioned sequences, the most intense competitiveness for the adsorption and retention of different metals appears between

  9. Phytoremediation efficiency of pondweed (Potamogeton crispus in removing heavy metals (Cu, Cr, Pb, As and Cd from water of Anzali wetland

    Directory of Open Access Journals (Sweden)

    Hajar Norouznia

    2014-09-01

    Full Text Available Plant-based remediation (i.e. phytoremediation is one of the most significant eco-sustainable techniques to cope with devastating consequences of pollutants. In the present study, the potential of a wetland macrophyt (i.e. Potamogeton crispus for the phytoremediation of heavy metals (i.e. Cu, Cr, Pb, As and Cd in the Anzali wetland was evaluated. The results showed that P. crispus tends to accumulate notable amounts of Cu, Cr, Pb, As and Cd according to their assayed concentrations as follows: 8.2 µg g-1 dw, 0.97 µg g-1 dw, 6.04 µg g-1 dw, 2.52 µg g-1 dw and 0.34 µg g-1 dw, respectively. Further accurate perception of the phytoremediation efficiency were conducted using both bioconcentration factor and translocation factor. The average of the highest bioconcentration factors was presented in a descending order as: 2.9×103, 1.9×103, 1.17×103, 0.68×103 and 0.46×103 for the Cu, Cr, Pb, Cd and As, respectively. Based on the results, P. crispus presents high potential to absorb all the alluded metals except for As and partly Cd. Correspondingly, the mean values of translocation factor were reported in the range of 0.41 to 2.24. Eventually, relying on the observed findings, the results support the idea that P. crispus species would be employed as the prospective candidate for the phytoremediation processes in Anzali wetland.

  10. The relationships between heavy metal (Cd, Cr, Cu, Fe, Pb, Zn) levels and the size of six Mediterranean fish species

    International Nuclear Information System (INIS)

    Canli, Mustafa; Atli, Gueluezar

    2003-01-01

    Significant relationships between metal concentrations and fish size were negative. - Heavy metal (Cd, Cr, Cu, Fe, Pb, Zn) concentrations in the muscle, gill and liver of six fish species (Sparus auratus, Atherina hepsetus, Mugil cephalus, Trigla cuculus, Sardina pilchardus and Scomberesox saurus) from the northeast Mediterranean Sea were measured and the relationships between fish size (length and weight) and metal concentrations in the tissues were investigated by linear regression analysis. Metal concentrations (as μg/g d.w.) were highest in the liver, except for iron in the gill of Scomberesox saurus and lowest in the muscle of all the fish species. Highest concentrations of Cd (4.50), Cr (17.1) and Pb (41.2) were measured in liver tissues of T. cuculus, Sardina pilchardus and A. hepsetus, respectively. The liver of M. cephalus showed strikingly high Cu concentrations (202.8). The gill of Scomberesox saurus was the only tissue that showed highest (885.5) iron concentrations. Results of linear regression analysis showed that, except in a few cases, significant relationships between metal concentrations and fish size were negative. Highly significant (P<0.001) negative relationships were found between fish length and Cr concentrations in the liver of A. hepsetus and M. cephalus, and Cr concentrations in the gill of T. cuculus. Cr and Pb concentrations in the liver and Cu concentrations in all the tissues of Scomberesox saurus also showed very significant (P<0.001) negative relationships. Negative relationships found here were discussed

  11. Simultaneous removal of As, Cd, Cr, Cu, Ni and Zn from stormwater using high-efficiency industrial sorbents: Effect of pH, contact time and humic acid

    DEFF Research Database (Denmark)

    Genc-Fuhrman, Hülya; Mikkelsen, Peter Steen; Ledin, Anna

    2016-01-01

    The effect of contact time, solution pH, and the presence of humic acid (HA) on the combined removal of As, Cd, Cr, Cu, Ni and Zn is investigated in batch tests using alumina, granulated activated carbon (GAC), and bauxsol coated sand (BCS) as sorbents. It is found that the equilibrium time for Cd......, Cu, Ni and Zn is about 4 h, while no clear equilibrium is observed for As and Cr. It is also found that increasing the pH until pH ~. 8 enhanced Cd, Cu, Ni and Zn removal, but increasing the pH above this point had no major effect. In the cases of As and Cr, higher pH values (i.e. >. 7) decreased...... that natural organic matter may severely influence the removal efficiency, such that, for most metals the removal was reduced to the half, while for Cr it was increased to the double for alumina and BCS. Consequently, a properly working filter set up may not work properly anymore when receiving high loads...

  12. Mobility and bioavailability of Cd, Co, Cr, Cu, Mn and Zn in surface runoff sediments in the urban catchment area of Guwahati, India

    Science.gov (United States)

    Devi, Upama; Bhattacharyya, Krishna G.

    2018-03-01

    The sediments in stormwater runoff are recognised as the major sink of the heavy metals and affect the soil quality in the catchment. The runoff sediments are also important in the management of contaminant transport to receiving water bodies. In the present work, stormwater during several major rain events was collected from nine principal locations of Guwahati, India. The solid phase was separated from the liquid phase and was investigated for the total contents of Cd, Co, Cr, Cu, Mn and Zn as well as their distribution among the prominent chemical phases. Sequential extraction procedure was used for the chemical fractionation of the metals that contains five steps. The total metal concentration showed the trend, Cd < Co < Cu < Cr < Zn < Mn. The relative distribution of the metals showed that Cd was available mostly in the exchangeable and the carbonate bound fractions, which were the most mobile and high-risk fractions. Co with medium mobility was also found to be in the high-risk category. On the other hand, the mobilities of Cu and Zn were relatively low and these were, therefore, the least bioavailable metals in the runoff sediments falling in medium-risk category.

  13. Flotation separation of Cd, Co, Cr, Cu, Ni and Tl from calcium minerals and their determination by inductively coupled plasma-atomic emission spectrometry

    International Nuclear Information System (INIS)

    Zajkova-Paneva, Vesna; Stafilov, Trajche; Boev, Blazho

    2003-01-01

    The method of inductively coupled plasma-atomic spectrometry (ICP-AES), is developed for determination of Cd, Co, Cr, Cu, Ni and Tl in traces in calcite and gypsum. The interferences of Ca as matrix element on Co, Cr, Cu, Ni and Tl intensities during their ICP-AES determination are investigated. The results reveal that Ca does not interfere on intensities of Cr, but tends to decrease the intensity of the other elements. To eliminate those matrix interferences of Ca on trace elements intensities a flotation separation method is proposed. Lead(II) hexamethylenedithiocarbamate, Pb(HMDTC) 2 , is applied as a collector for flotation of trace elements from acidic solutions of mineral samples. The most suitable concentrations of calcite and gypsum solutions for flotation are ascertained. The detection limits of ICP-AES method following flotation of elements present in calcite and gypsum as impurities are determined: 0.022 and 0.061 μg·g -1 for Cd, 0.071 and 0.042 μg·g -1 for Co, 0.026 and 0.132 μg·g -1 for Cr, 0.164 and 0.149 μg·g -1 for Cu, 0.289 and 0.095 μg·g -1 for Ni and 0.645 and 0.7666 μg·g -1 for Tl, respectively. (Original)

  14. Microstructure and Mechanical Characterization of a Dissimilar Friction-Stir-Welded CuCrZr/CuNiCrSi Butt Joint

    Directory of Open Access Journals (Sweden)

    Youqing Sun

    2018-05-01

    Full Text Available Dissimilar CuNiCrSi and CuCrZr butt joints were successfully frictionstirwelded at constant welding speed of 150 mm/min and rotational speed of 1400 rpm with the CuCrZr alloy or the CuNiCrSi alloy located on the advancing side (AS. The microstructure and mechanical properties of joints were investigated. When the CuCrZr alloy was located on the AS, the area of retreating material in the nugget zone was a little bigger. The Cr solute-rich particles were found in the nugget zone on CuCrZr side (CuCrZr-NZ while a larger density of solute-rich particles identified as the concentration of Cr and Si element was found in the nugget zone on CuNiCrSi side (CuNiCrSi-NZ. The Cr precipitates and δ-Ni2Si precipitates were found in the base metal on CuNiCrSi side (CuNiCrSi-BM but only Cr precipitates can be observed in the base metal on CuCrZr side (CuCrZr-BM. Precipitates were totally dissolved into Cu matrix in both CuCrZr-NZ and CuNiCrSi-NZ, which led to a sharp decrease in both micro-hardness and tensile strength from BM to NZ. When the CuNiCrSi was located on the AS, the tensile testing results showed the fracture occurred at the CuCrZr-NZ, while the fracture was found at the mixed zone of CuNiCrSi-NZ and CuCrZr-NZ for the other case.

  15. Speciation of Cr, Co, Cu, Cd, Zn and Pbin the sediment of Almendares river

    International Nuclear Information System (INIS)

    De La Rosa, D.; Olivares, S.; Lima, L.; Borroto, J.; Santana, J.L.; Gonzalez, M.; Ravelo, R.

    2004-01-01

    This work presents the speciation of Cr, Co, Cu, Cd, Zn and Pbin the sediment of Almendares river. The procedure of sequential extraction in three steps (SM and T) was used and the levels of metals in the residual phase were determined. The lake sediment sample (CRM-BCR 601) specific for this process, was used for the validation of the sample from the river. Detection limits and quantification acceptable for the determination of metals were achieved by the use of the method of analysis with AAE. Parameters as repeatability and reproducibility of the equipment, of the extraction method, and of the digestion of the sample, as well as the influence of the extrayents solutions in the different step of solution were evaluated

  16. Cu-Cr Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Need, Ryan F. [Los Alamos National Laboratory

    2012-08-09

    Cu-Cr alloys are part of a class of face-centered cubic (FCC)-body-centered cubic (BCC) composites that includes similar alloys, such as Cu-Nb and Cu-Ta. When heavily deformed, these FCC-BCC materials create 'in situ' composites with a characteristic structure-nanoscale BCC filaments in a ductile FCC matrix. The strength of these composites is vastly greater than predicted by the rule of mixtures, and has been shown to be inversely proportional to the filament spacing. Lower raw materials costs suggest that Cu-Cr alloys may offer more economical solution to high-strength, high-conductivity wire than either their Nb or Ta counterparts. However, Cr is also more brittle and soluble in Cu than Nb or Ta. These qualities necessitate thermal treatments to remove solute atoms from the Cu matrix, improve conductivity, and maintain the ductility of the Cr filaments. Through the use of different thermomechanical processing routes or the addition of select dopants, alloys with strength in excess of 1 GPa at 70% IACS have been achieved. To date, previous research on Cu-Cr alloys has focused on a relatively small number of alloy compositions and processing methods while the effects of dopants and ageing treatments have only been studied independently. Consequently, there remains considerable opportunity for the development and optimization of these alloys as a leading high-strength, high-conductivity material.

  17. Evaluation of Cd, Cr, Cu, Ni, and Pb in selected cosmetic products from Jordanian, Sudanese, and Syrian markets.

    Science.gov (United States)

    Massadeh, A M; El-Khateeb, M Y; Ibrahim, S M

    2017-08-01

    There is no sufficient data that evaluate heavy metal content in cosmetic products in Jordan as well as Sudan and Syria. This study aims to assess metal levels which include Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), and Lead (Pb) in cosmetic products. These elements have draft limits because they are identified as potential impurities and are known to be toxic. This study aims to provide information to the population that may be beneficial to public health. Samples were collected from different brands obtained from markets in Jordan, Sudan, and Syria. Some of the selected cosmetic products were eyeliner, eye pencil, mascara, lipstick, powder, face cream, body cream, sun block, Vaseline, and the traditional eye cosmetic (kohl). The heavy metal content in these samples were determined by atomic absorption spectrometry (AAS). Based on analysis of variance analysis, a significant difference in heavy metal levels was found for samples obtained from Jordanian and Sudanese markets. The acid digestion method used in this study was based on procedures recommended by Nnorom et al. with some modifications as follows. (i) A weight of 2.0 g of cosmetic sample was dissolved in a mixture of 6 mL of high quality concentrated 69% nitric acid (HNO 3 ; Merck, Darmstadt, Germany) and 4 mL of concentrated 37% hydrochloric acid (Scharlau, Spain) in a porcelain crucible and heated on a hotplate to near dryness. (ii) An aliquot of 15 mL HNO 3 (1.00 M) was added to the digested sample and filtered through a Whatman No. 40 filter paper. (iii) The digested sample was transferred quantitatively into a 25 mL volumetric flask and then diluted with deionized water. (iv) Each digested sample was evaporated at 70 °C to about 1 mL and transferred into a polyethylene flask and diluted with 25 mL deionized water. (v) Blank was treated in the same procedure. In Jordan the concentration ranges of heavy metals in the collected samples were: Cd (0.03-0.10 μg/g), Cr (0.0-1.00

  18. Analysis Of Non-Volatile Toxic Heavy Metals (Cd, Pb, Cu,Cr And Zn In ALLIUM SATIVUM (Garlic And Soil Samples ,Collected From Different Locations Of Punjab, Pakistan By Atomic Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Ata S.

    2013-04-01

    Full Text Available Garlic is one of the most widely used medicinal plants. The monitoring of toxic metals such as lead, Cadmium, Chromium, Copper and Zinc in garlic and the soil of garlic fields collected from ten different cities of Punjab is critical for preventing public health against the hazards of metal toxicity. The levels of toxic heavy metals in garlic and soil samples were investigated using Atomic absorption spectrometer. The metal content in garlic samples was found to be in increasing order as Cr> Pb> Cd> Cu> Zn. Infield metal content in the soil also followed the same trend. In garlic samples, Pb, Cd, Cr, Zn and Cu ranged from 0.039mg/L to 0.757mg/L, N.D to 1.211mg/L, 0.03mg/L to 0.451mg/L, 0.02mg/Lto0.42mg/L and 0.451mg/L to 0.893mg/L respectively. In soil samples, Pb, Cd, Cr, Zn and Cu were ranged from 0.459mg/L to 0.797mg/L, 0.205mg/L to1.062mg/L, 0.074mg/L to 2.598mg/L, 0.124mg/L to 0.276mg/L and 0.494mg/L to 0.921mg/L respectively. In our study, the Pb and Cd was found more in garlic from Gujranwala and Jaranwala, Cu and Zn were more in samples from Kasur while Cr was predominant in sample from Sheikhupura. Heavy metal content in soil and garlic samples was within the permissible limits proposed by World Health Organization (WHO.

  19. Simultaneous removal of As, Cd, Cr, Cu, Ni and Zn from stormwater using high-efficiency industrial sorbents: Effect of pH, contact time and humic acid.

    Science.gov (United States)

    Genç-Fuhrman, Hülya; Mikkelsen, Peter S; Ledin, Anna

    2016-10-01

    The effect of contact time, solution pH, and the presence of humic acid (HA) on the combined removal of As, Cd, Cr, Cu, Ni and Zn is investigated in batch tests using alumina, granulated activated carbon (GAC), and bauxsol coated sand (BCS) as sorbents. It is found that the equilibrium time for Cd, Cu, Ni and Zn is about 4h, while no clear equilibrium is observed for As and Cr. It is also found that increasing the pH until pH~8 enhanced Cd, Cu, Ni and Zn removal, but increasing the pH above this point had no major effect. In the cases of As and Cr, higher pH values (i.e. >7) decreased their removal. The presence of both 20 and 100mg/L HA suppressed the heavy metal removal except for Cr, and the suppression was higher at the higher HA concentration. Geochemical simulations suggest that this is due to the formation of dissolved HA-metal complexes preventing effective metal sorption. In the case of Cr, the presence of HA increased the removal when using alumina or BCS, while hindering the removal when using GAC. The findings show that the pH-value of the stormwater to be treated must be in the range of 6-7 in order to achieve removal of the full spectrum of metals. The results also show that natural organic matter may severely influence the removal efficiency, such that, for most metals the removal was reduced to the half, while for Cr it was increased to the double for alumina and BCS. Consequently, a properly working filter set up may not work properly anymore when receiving high loads of natural organic acids during the pollen season in spring or during defoliation in autumn and early winter, and during mixing of runoff with snowmelt having a low pH. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Observations of a Cast Cu-Cr-Zr Alloy

    Science.gov (United States)

    Ellis, David L.

    2006-01-01

    Prior work has demonstrated that Cu-Cr-Nb alloys have considerable advantages over the copper alloys currently used in regeneratively cooled rocket engine liners. Observations indicated that Zr and Nb have similar chemical properties and form very similar compounds. Glazov and Zakharov et al. reported the presence of Cr2Zr in Cu-Cr-Zr alloys with up to 3.5 wt% Cr and Zr though Zeng et al. calculated that Cr2Zr could not exist in a ternary Cu-Cr-Zr alloy. A cast Cu-6.15 wt% Cr-5.25 wt% Zr alloy was examined to determine if the microstructure developed would be similar to GRCop-84 (Cu-6.65 wt% Cr-5.85 wt% Nb). It was observed that the Cu-Cr-Zr system did not form any Cr2Zr even after a thermal exposure at 875 C for 176.5 h. Instead the alloy consisted of three phases: Cu, Cu5Zr, and Cr.

  1. Removal of As, Cd, Cr, Cu, Ni and Zn from polluted water using an iron based sorbent

    DEFF Research Database (Denmark)

    Genc-Fuhrman, Hülya; Wu, P.; Zhou, Y.

    2008-01-01

    In this study fixed-bed sorption filters are filled with an iron based sorbent (ferrosorp plus, FP) and used to remove a range of heavy metals (i.e. As, Cd, Cr, Cu, Ni, and Zn) from polluted water. It is found that FP is very effective at simultaneous removal of the heavy metals, and the magnitude...... inflow pH of 6.8 and heavy metal concentration of ≈2.8 μM. It is concluded that FP has high affinity to heavy metals and it can be used (e.g. as a filter medium) to treat waters containing a wide range of heavy metals, e.g. stormwater, industrial wastewater....

  2. Phase relationships in Cu-rich corner of the Cu-Cr-Zr phase diagram

    International Nuclear Information System (INIS)

    Zeng, K.J.; Haemaelaeinen, M.; Lilius, K.

    1995-01-01

    In the available experimental information on the Cu-Cr-Zr ternary system, there exist different opinions concerning the phase relationships in the Cu-rich corner of Cu-Cr-Zr phase diagram. Glazov et al. and Zakharov et al. investigated the Cu-rich corner of the Cu-Cr-Zr phase diagram within the composition range up to 3.5 Cr and 3.5 Zr (wt. %). A quasi-eutectic reaction L → (Cu) + αCr 2 Zr was observed to occur at 1,020 C and several isothermal sections were constructed within the temperature range from 600 to 1,000 C to show the (Cu)-αCr 2 Zr two phase equilibrium. Therefore, a pseudobinary Cu-Cr 2 Zr system was supposed. Afterwards, Dawakatsu et al, Fedorov et al, and Kuznetsov et al studied the cu-rich corner of the phase diagram in a wider composition range up to 5 Cr and 20 Zr (at.%). Contrary to Glazov et al. and Zakharov et al., they found no Cr 2 Zr phase in their samples. Hence, the pseudobinary Cu-Cr 2 Zr system does not exist. In this study an experimental investigation is presented on the phase relationships in Cu-rich corner of the Cu-Cr-Zr phase diagram at 940 C in order to clear up the confusion

  3. Essential trace (Zn, Cu, Mn and toxic (Cd, Pb, Cr elements in the liver of birds from Eastern Poland

    Directory of Open Access Journals (Sweden)

    Komosa A.

    2012-01-01

    Full Text Available We have focused our study on the concentrations of essential heavy metals (Zn, Cu and Mn and non-essential trace metals (Pb, Cd and Cr in the livers of birds from Eastern Poland. The largest mean amount of Zn - as much as 279 mg/kg dry mass (d.m. - was found in mute swans. However, only in one of the analysed buzzard specimens the concentration of Zn, found to be 664 mg/kg d.m., exceeded the level indicative of poisoning for this element. Birds specializing in catching rodents accumulated Mn in their livers in a very narrow range of concentrations, around 5.0 mg/kg d.m. on average. The range of mean Mn concentrations (around 6.5 mg/kg d.m. was also found to be narrow for piscivorous birds. The highest mean levels of Pb were found in mute swans (2.7 mg/kg d.m., and the highest levels of Cd (2.0 mg/kg d.m. for rooks. Concentrations of total Cr above detection level were found in 22 specimens (53.7%, and concentration values were highest for rooks. Analyses showed that the concentrations of biogenic elements did not exceed the levels indicative of poisoning (except in one specimen. The study demonstrated that lead shots remain a hazard to water ecosystems. Pb, Cd and Cr levels in the livers of omnivorous and piscivorous species indicate the permanent presence of these elements in the environment and may confirm the thesis about the growing role of electronic waste, including metallic e-waste, in the emission of the total amount of contamination with these elements.

  4. Mechanical properties and electrical conductivity of Cu-Cr and Cu-Cr-4% SiC nanocomposites for thermo-electric applications

    International Nuclear Information System (INIS)

    Mula, Suhrit; Sahani, Pankajini; Pratihar, S.K.; Mal, Siddhartha; Koch, Carl C.

    2011-01-01

    Highlights: → Ball-milled Cu-Cr and Cu-Cr-SiC nanopowders successfully consolidated by microwave sintering. → Addition of nanosize SiC in Cu-Cr leads to enhanced sintered density, wear and hardness. → A good combination of wear resistance, hardness and electrical conductivity resulted in Cu 94 Cr 6 -4% SiC. → Microwave suscepting SiC particles played a pivotal role in good densification retaining matrix grains 99 Cr 1 , Cu 94 Cr 6 , Cu 99 Cr 1 -4 wt.% SiC and Cu 94 Cr 6 -4 wt.% SiC (average particle size ∼30 nm). The 50 h ball-milled samples were uniaxially pressed, and then pellets were sintered at 800 deg. C, 900 deg. C and 1000 deg. C for a constant soaking period of 30 min by microwave sintering technique. Microstructural characterization was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Sintered compacts resulted a highly densified compacts (∼95% relative density) while retaining ultra-fine grains (100-200 nm) in the matrix. The mechanical properties, namely, hardness and wear resistance, and electrical conductivity of the sintered specimens were also evaluated. The best combination of mechanical properties (e.g. hardness ∼2.4 GPa) and electrical conductivity (60.3% of IACS) were obtained for Cu 94 Cr 6 -4 wt.% SiC sintered at 900 deg. C. This is possibly due to presence of ultra-fine grains in the bulk samples, good densification and proper bonding between particles. The results were analyzed in the light of interactions of microwaves between metallic matrix and microwave susceptive SiC particulates.

  5. Study of surfaces and interfaces in CdS-Cu2S and (Cd sub(x) Zn sub(1-x))S-Cu2S solar cells

    International Nuclear Information System (INIS)

    Dhere, N.G.; Dhere, R.G.; Bloss, W.H.; Schock, H.W.; Bauer, E.; Cyris, P.

    1983-01-01

    Auger microprobe was used for the analysis of interfaces and surfaces in several stages involved in the preparation of solar cells, in order to study the origin of adhesion problems and to study the formation of CdS-Cu 2 S barrier by the wet method. The detachment of the first CdS and (Cd sub(x) Zn sub(1-x))S films, during the dip process, was attributed to the contamination of Cr-Ag metallic substrates by existing chlorine from the environment next to the sea, due to long film stocking, by degasified species from the evaporating material and by the ejection of particles together with CdS vapour during deposition. The formation of conical mounds on the surface and of the CdS-Cu 2 S barrier at aproximatelly 3000 A depth in the dipped samples were observed. The migration of copper towards surface direction and the formation of a superficial thin layer of copper oxide after treatment in H 2 plasma and air heating, were also verified. (C.L.B.) [pt

  6. Novel CuCr_2O_4 embedded CuO nanocomposites for efficient photodegradation of organic dyes

    International Nuclear Information System (INIS)

    Mageshwari, K.; Sathyamoorthy, R.; Lee, Jeong Yong; Park, Jinsub

    2015-01-01

    Graphical abstract: - Highlights: • Novel CuO–CuCr_2O_4 nanocomposites synthesized by reflux condensation method. • Methyl orange and methylene blue dye degradation studied under UV light irradiation. • Nanocomposites characterized by XRD, FESEM, TEM, EDX, UV–vis DRS and PL. • CuCr_2O_4 loading effectively enhanced the catalytic activity of CuO. - Abstract: Novel photocatalyst based on CuO–CuCr_2O_4 nanocomposites was synthesized for different Cr"3"+ concentration by reflux condensation method, and their photocatalytic activity was evaluated by monitoring the photodegradation of methyl orange (MO) and methylene blue dyes (MB) under UV light irradiation. Phase evolution by X-ray diffraction showed monoclinic CuO and tetragonal CuCr_2O_4 as the components of the prepared nanocomposites. Morphological analysis by scanning electron microscope and transmission electron microscope revealed that the incorporation of Cr"3"+ in CuO lattice alters the morphology of CuO from microsphere to cluster shape. Photoluminescence spectra of CuO–CuCr_2O_4 nanocomposites exhibited reduced PL emissions compared to pure CuO, indicating the low recombination rate of photogenerated electrons and holes. As expected, the CuCr_2O_4 loaded CuO showed enhanced photocatalytic activity for MO and MB dyes, and the kinetic studies suggest that the degradation follows pseudo-first-order kinetics. The enhanced photocatalytic activity of CuO–CuCr_2O_4 nanocomposites can be attributed to the presence of CuCr_2O_4 as an electron acceptor, which improves the effective charge separation in CuO.

  7. Deuterium transport in Cu, CuCrZr, and Cu/Be

    Science.gov (United States)

    Anderl, R. A.; Hankins, M. R.; Longhurst, G. R.; Pawelko, R. J.

    This paper presents the results of deuterium implantation/permeation experiments and TMAP4 simulations for a CuCrZr alloy, for OFHC-Cu and for a Cu/Be bi-layered structure at temperatures from 700 to 800 K. Experiments used a mass-analyzed, 3-keV D 3+ ion beam with particle flux densities of 5 × 10 19 to 7 × 10 19 D/m 2 s. Effective diffusivities and surface molecular recombination coefficients were derived giving Arrhenius pre-exponentials and activation energies for each material: CuCrZr alloy, (2.0 × 10 -2 m 2/s, 1.2 eV) for diffusivity and (2.9 × x10 -14 m 4/s, 1.92 eV) for surface molecular recombination coefficients; OFHC Cu, (2.1 × 10 -6 m 2/s, 0.52 eV) for diffusivity and (9.1 × 10 -18 m 4/s, 0.99 eV) for surface molecular recombination coefficients. TMAP4 simulation of permeation data measured for a Cu/Be bi-layer sample was achieved using a four-layer structure (Cu/BeO interface/Be/BeO back surface) and recommended values for diffusivity and solubility in Be, BeO and Cu.

  8. Effects of processing parameters on Be/CuCrZr joining

    International Nuclear Information System (INIS)

    Park, Jeong-Yong; Lee, Jung-Suk; Choi, Byung-Kwon; Park, Sang-Yun; Hong, Bong Guen; Jeong, Yong Hwan; Jung, Ki-Jung

    2007-01-01

    A joining of Be/CuCrZr has been considered as the key technology for the fabrication of the ITER first wall. Among the joining methods, Hot isostatic pressing (HIP), which is one of the diffusion bonding methods, is the most feasible method to join the Be and CuCrZr alloy. In the HIP joining of Be and CuCrZr, the interlayer was used to prevent the formation of brittle intermetallic compounds in the interface. Therefore, it is crucial to select a suitable interlayer for a joining of Be and CuCrZr. On the other hand, the diffusion between Be and CuCrZr would be enhanced with an increase of the HIP joining temperature, thereby increasing the joint strength. However, the HIP joining temperature is limited by the mechanical properties of CuCrZr. During the fabrication process of the ITER first wall, CuCrZr is subjected to several thermal cycles including a solution annealing, a cooling and an aging. The HIP joining of Be and CuCrZr corresponds to the aging of CuCrZr. The HIP joining at a higher temperature would cause a degradation of the mechanical properties of CuCrZr by an overaging effect although it is preferable for an improvement of the joint strength. In this study, the effect of the cooling rate on the mechanical properties of aged CuCrZr was investigated to find the maximum HIP temperature without a degradation of the mechanical properties of CuCrZr

  9. Crystal structure, Raman scattering and magnetic properties of CuCr2-xZrxSe4 and CuCr2-xSnxSe4 selenospinels

    Science.gov (United States)

    Pinto, C.; Galdámez, A.; Barahona, P.; Moris, S.; Peña, O.

    2018-06-01

    Selenospinels, CuCr2-xMxSe4 (M = Zr and Sn), were synthesized via conventional solid-state reactions. The crystal structure of CuCr1.5Sn0.5Se4, CuCr1.7Sn0.3Se4, CuCr1.5Zr0.5Se4, and CuCr1.8Zr0.2Se4 were determined using single-crystal X-ray diffraction. All the phases crystallized in a cubic spinel-type structure. The chemical compositions of the single-crystals were examined using energy-dispersive X-ray analysis (EDS). Powder X-ray diffraction patterns of CuCr1.3Sn0.7Se4 and CuCr1.7Sn0.3Se4 were consistent with phases belonging to the Fd 3 bar m Space group. An analysis of the vibrational properties on the single-crystals was performed using Raman scattering measurements. The magnetic properties showed a spin glass behavior with increasing Sn content and ferromagnetic order for CuCr1.7Sn0.3Se4.

  10. Comparison of the Isothermal Oxidation Behavior of As-Cast Cu-17%Cr and Cu-17%Cr-5%Al. Part 1; Oxidation Kinetics

    Science.gov (United States)

    Raj. Sai V.

    2008-01-01

    The isothermal oxidation kinetics of as-cast Cu-17%Cr and Cu-17%Cr-5%Al in air were studied between 773 and 1173 K under atmospheric pressure. These observations reveal that Cu- 17%Cr-5%Al oxidizes at significantly slower rates than Cu-17%Cr. The rate constants for the alloys were determined from generalized analyses of the data without an a priori assumption of the nature of the oxidation kinetics. Detailed analyses of the isothermal thermogravimetric weight change data revealed that Cu-17%Cr exhibited parabolic oxidation kinetics with an activation energy of 165.9 9.5 kJ mol-1. In contrast, the oxidation kinetics for the Cu-17%Cr- 5%Al alloy exhibited a parabolic oxidation kinetics during the initial stages followed by a quartic relationship in the later stages of oxidation. Alternatively, the oxidation behavior of Cu-17%CR- 5%Al could be better represented by a logarithmic relationship. The parabolic rate constants and activation energy data for the two alloys are compared with literature data to gain insights on the nature of the oxidation mechanisms dominant in these alloys.

  11. Photovoltaic properties of sintered CdS/CdTe solar cells doped with Cu

    International Nuclear Information System (INIS)

    Park, J.W.; Ahn, B.T.; Im, H.B.; Kim, C.S.

    1992-01-01

    In this paper, all polycrystalline CdS/CdTe solar cells doped with Cu are prepared by a screen printing and sintering method. Cell parameters of the sintered CdS/CdTe solar cells have been investigated in an attempt to find out the optimum doping conditions and concentrations of Cu by adding various amounts of CuCl 2 either into CdTe layer or into back contact carbon layer. Cell parameters of the sintered CdS/CdTe solar cells which contained various amounts of CuCl 2 in the CdTe layers before sintering stay at about the same values as the amount of CuCl 2 increases up to 25 ppm, and then decreases sharply as the amount of CuCl 2 further increases. The Cu added in the CdTe layer diffuses into the CdS layer during the sintering of the CdS-CdTe composite at 625 degrees C to densify the CdTe layer and causes the decrease in the optical transmission of CdS resulting in the degradation of the cell performance. In case the Cu dopant was dispersed in the back carbon paint and was followed by annealing, all cell parameters are improved significantly compared with those fabricated by adding CuCl 2 in the CdTe layer before sintering. A sintered CdS/CdTe solar cell which contained 25 ppm CuCl 2 in the carbon paste and was annealed at 350 degrees C for 10 min shows the highest efficiency. The efficiency of this cell is 12.4% under solar irradiation with an intensity of 80.4 mW/cm 2

  12. Diffusion and influence of Cu on properties of CdTe thin films and CdTe/CdS cells

    Energy Technology Data Exchange (ETDEWEB)

    Dzhafarov, T.D.; Yesilkaya, S.S.; Yilmaz Canli, N.; Caliskan, M. [Department of Physics, Yildiz Technical University, Davutpasa, 34210 Istanbul (Turkey)

    2005-01-31

    The effective diffusion coefficients of Cu for thermal and photodiffusion in the CdTe films have been estimated from resistivity versus duration of thermal or photoannealing curves. In the temperature range 60-200{sup o}C the effective coefficient of thermal diffusion (D{sub t}) and photodiffusion (D{sub ph}) are described as D{sub t}=7.3x10{sup -7}exp(-0.33/kT) and D{sub ph}=4.7x10{sup -8}exp(-0.20/kT). It is found that the diffusion doping of CdTe thin films by Cu at 400{sup o}C results in a sharp decrease of resistivity up to 7 orders of magnitude of p-type material, depending on thickness of Cu film. The comparative study of performance of CdTe(Cu)/CdS and CdTe/CdS cells has been studied. It is shown that the diffusion doping of CdTe film by Cu increases efficiency of CdTe(Cu)/CdS cells from 0.9% to 6.8%. The degradation of photovoltaic parameters of CdTe(Cu)/CdS cell, during testing under forward and reverse bias at room temperature, proceeds at a larger rate than those of CdTe/CdS cell without Cu. The degradation of performance of CdTe(Cu)/CdS cells is tentatively assigned to electrodiffusion of Cu in CdTe, resulting in redistribution of concentration of Cu-related centers in CdTe film and heterojunction region.

  13. Optical properties of CuCdTeO thin films sputtered from CdTe-CuO composite targets

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza-Galván, A., E-mail: amendoza@qro.cinvestav.mx [Cinvestav-IPN, Unidad Querétaro, Libramiento Norponiente 2000, 76230 Querétaro (Mexico); Laboratory of Applied Optics, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Arreola-Jardón, G. [Cinvestav-IPN, Unidad Querétaro, Libramiento Norponiente 2000, 76230 Querétaro (Mexico); Karlsson, L.H.; Persson, P.O.Å. [Thin Film Physics Division, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Jiménez-Sandoval, S. [Cinvestav-IPN, Unidad Querétaro, Libramiento Norponiente 2000, 76230 Querétaro (Mexico)

    2014-11-28

    The effective complex dielectric function (ε) of Cu and O containing CdTe thin films is reported in the spectral range of 0.05 to 6 eV. The films were fabricated by rf sputtering from targets comprised by a mixture of CdTe and CuO powders with nominal Cu and O concentrations in the range of 2–10 at.%. Low concentration levels improved the crystalline quality of the films. Spectroscopic ellipsometry and transmittance measurements were used to determine ε. The critical point energies E{sub 1}, E{sub 1} + Δ{sub 1}, and E{sub 2} of CdTe are red-shifted with the incorporation of Cu and O. Also, an absorption band is developed in the infrared range which is associated with a mixture of CdTe and low resistivity phases Cu{sub 2−x}Te according to an effective medium analysis. The elemental distribution of the films was mapped by energy dispersive X-ray spectroscopy using scanning transmission electron microscopy. - Highlights: • Incorporation of 2 to 10 at.% of Cu and O atoms in CdTe films • Improved crystalline quality with 2 and 3 at.% of Cu and O • Complex dielectric function of Cu and O containing CdTe thin films • Effective medium modeling of below band-gap absorption.

  14. THE EFFECT OF RARE EARTH ELEMENTS ON Cr PRECIPITATIONS IN A Cu-0.8WT%Cr ALLOY

    Directory of Open Access Journals (Sweden)

    Gewang Shuai

    2011-05-01

    Full Text Available The microstructural evolution of Cu-based alloys during aging was studied using a quantitative metallographic method. Samples were cut from ingots of Cu-0.8wt%Cr and Cu-0.8wt%Cr-RE alloys. These were solution treated at 1000 ºC for 1.5h and subsequently quenched in water, then separately aged at 480 ºC for different durations. The microstructures were observed by optical microscope, and the characteristic geometric parameters of precipitated Cr phase, including volume fraction VV, face density NA, mean diameter and roundness, were measured. These data provided more details about the process of aging. The results showed that precipitation of Cr phase occurred in the form of particles during aging. Rare earth elements promoted the precipitation of Cr phase and dispersed Cr particles. The phenomenon of overaging came earlier in Cu-Cr-RE than in Cu-Cr. In the present work, the optimal aging time at 480 ºC was 2 hrs for the Cu-0.8wt%Cr-RE alloy and 3 hours for the Cu-0.8wt%Cr alloy.

  15. Genotoxicity and cytotoxicity response to environmentally relevant complex metal mixture (Zn, Cu, Ni, Cr, Pb, Cd) accumulated in Atlantic salmon (Salmo salar). Part I: importance of exposure time and tissue dependence.

    Science.gov (United States)

    Stankevičiūtė, Milda; Sauliutė, Gintarė; Svecevičius, Gintaras; Kazlauskienė, Nijolė; Baršienė, Janina

    2017-10-01

    Health impact of metal mixture at environment realistic concentrations are difficult to predict especially for long-term effects where cause-and-effect relationships may not be directly obvious. This study was aimed to evaluate metal mixture (Zn-0.1, Cu-0.01, Ni-0.01, Cr-0.01, Pb-0.005 and Cd-0.005 mg/L, respectively for 1, 2, 4, 7, 14 and 28 days at concentrations accepted for the inland waters in EU) genotoxicity (micronuclei, nuclear buds, nuclear buds on filament), cytotoxicity (8-shaped nuclei, fragmented-apoptotic erythrocytes), bioaccumulation, steady-state and the reference level of geno-cytotoxicity in hatchery-reared Atlantic salmon tissues. Metals accumulated mostly in gills and kidneys, to the lesser extent in the muscle. Uptake of metals from an entire mixture in the fish for 14 days is sufficient to reach steady-state Cr, Pb concentrations in all tissues; Zn, Cu-in kidneys and muscle, Ni-in liver, kidneys, muscle and Cd-in muscle. Treatment with metal mixture significantly increased summed genotoxicity levels at 7 days of exposure in peripheral blood and liver erythrocytes, at 14 days of exposure in gills and kidney erythrocytes. Significant elevation of cytotoxicity was detected after 2 and 14 days of exposure in gills erythrocytes and after 28 days-in peripheral blood erythrocytes. The amount of Cu, Cr, Pb and Cd accumulated in tissues was dependent upon duration of exposure; nuclear buds, 8-shaped nuclei frequencies also were dependent upon duration of exposure. This study indicates that metals at low levels when existing in mixture causes significant geno-cytotoxicity responses and metals bioaccumulation in salmon.

  16. Aging properties studies in a Cu-Ag-Cr Alloy

    International Nuclear Information System (INIS)

    Jia, S.G.; Zheng, M.S.; Liu, P.; Ren, F.Z.; Tian, B.H.; Zhou, G.S.; Lou, H.F.

    2006-01-01

    A Cu-Ag-Cr alloy was produced by means of vacuum induction melting. The effects of aging processes on microhardness and conductivity of Cu-Ag-Cr alloy were studied. The microstructure of the alloy was examined using transmission electron microscope (TEM). Aging at 450 deg. C for 4 h, the alloy has an excellent combination of microhardness and conductivity, the microhardness and conductivity reach 132 HV and 80% IACS, respectively. The precipitates responsible for the age-hardening effect are fcc Cr. The fine and dispersed precipitates are fully coherent with the Cu matrix and make the Cu-Ag-Cr alloy possesses higher hardness and conductivity

  17. Ultrathin Cr added Ru film as a seedless Cu diffusion barrier for advanced Cu interconnects

    Science.gov (United States)

    Hsu, Kuo-Chung; Perng, Dung-Ching; Yeh, Jia-Bin; Wang, Yi-Chun

    2012-07-01

    A 5 nm thick Cr added Ru film has been extensively investigated as a seedless Cu diffusion barrier. High-resolution transmission electron microscopy micrograph, X-ray diffraction (XRD) pattern and Fourier transform-electron diffraction pattern reveal that a Cr contained Ru (RuCr) film has a glassy microstructure and is an amorphous-like film. XRD patterns and sheet resistance data show that the RuCr film is stable up to 650 °C, which is approximately a 200 °C improvement in thermal stability as compared to that of the pure Ru film. X-ray photoelectron spectroscopy depth profiles show that the RuCr film can successfully block Cu diffusion, even after a 30-min 650 °C annealing. The leakage current of the Cu/5 nm RuCr/porous SiOCH/Si stacked structure is about two orders of magnitude lower than that of a pristine Ru sample for electric field below 1 MV/cm. The RuCr film can be a promising Cu diffusion barrier for advanced Cu metallization.

  18. Comparison of the Isothermal Oxidation Behavior of As-Cast Cu-17 Percent Cr and Cu-17 Percent Cr-5 Percent Al. Part 1; Oxidation Kinetics

    Science.gov (United States)

    Raj, S. V.

    2008-01-01

    The isothermal oxidation kinetics of as-cast Cu-17%Cr and Cu-17%Cr-5%Al in air were studied between 773 and 1173 K under atmospheric pressure. These observations reveal that Cu-17%Cr-5%Al oxidizes at significantly slower rates than Cu-17%Cr. The rate constants for the alloys were determined from generalized analyses of the data without an a priori assumption of the nature of the oxidation kinetics. Detailed analyses of the isothermal thermogravimetric weight change data revealed that Cu-17%Cr exhibited parabolic oxidation kinetics with an activation energy of 165.9+/-9.5 kJ/mol. In contrast, the oxidation kinetics for the Cu-17%Cr-5%Al alloy exhibited a parabolic oxidation kinetics during the initial stages followed by a quartic relationship in the later stages of oxidation. Alternatively, the oxidation behavior of Cu-17%CR-5%Al could be better represented by a logarithmic relationship. The parabolic rate constants and activation energy data for the two alloys are compared with literature data to gain insights on the nature of the oxidation mechanisms dominant in these alloys.

  19. R&D of CuCrZr tubes for W/Cu monoblock components

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Sixiang, E-mail: sxzhao@impcas.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), P.O. Box 1126, Hefei 230031 (China); Ma, Linsheng [State Nuclear Bao Ti Zirconium Industry Company, 206 Hi-Tech Avenue, Baoji 721013 (China); Peng, Lingjian [Advanced Technology & Materials Co., Ltd. - AT& M, Beijing 100081 (China); Gao, Bo [State Nuclear Bao Ti Zirconium Industry Company, 206 Hi-Tech Avenue, Baoji 721013 (China); Li, Chun [Laboratory of Advanced materials, School of Materials Science & Engineering, Tsinghua University, Beijing 100084 (China); Li, Qiang; Wang, Wanjing; Wei, Ran; Xu, Yuping [Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), P.O. Box 1126, Hefei 230031 (China); Pan, Ningjie; Qin, Sigui; Shi, Yingli; Liu, Guohui; Wang, Tiejun [Advanced Technology & Materials Co., Ltd. - AT& M, Beijing 100081 (China); Luo, Guang-Nan, E-mail: gnluo@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), P.O. Box 1126, Hefei 230031 (China); Hefei Center for Physical Science and Technology, Hefei 230031 (China); Hefei Science Center of CAS, Hefei 230031 (China)

    2016-11-15

    Highlights: • CuCrZr tubes with excellent HIP performance and good resistance to grain growth have been developed. • A circumferential ductility testing manner for small-diameter tubes has been utilized in this study. • The evolution of microstructures has been revealed throughout the new tube forming processes. - Abstract: In order to avoid the occurrence of two types of longitudinal defects (strain localization and folding flaws), which were observed in the CuCrZr tubes of EAST W/Cu upper divertor components, in the future manufacturing of monoblock components using hot isostatic pressing (HIP), a new CuCrZr tube forming protocol is proposed. The evolution of Cu grains and Cr-rich particles is monitored by scanning electron microscopy throughout the new tube forming processes. The final microstructures of the newly developed tubes are totally different from those of the EAST project previously chosen tubes and the elongation of Cr-rich precipitates has been substantially suppressed by using the new tube forming protocol. The newly developed tubes show better HIP performance than the EAST previously chosen ones. Since circumferential mechanical properties, especially ductility, are of great importance, a circumferential ductility testing manner for small-diameter tubes, which might be a supplement to longitudinal tensile testing, has been utilized and the preliminary testing results are given. The recrystallization behavior of the newly developed tubes is also investigated.

  20. Cu-Doped-CdS/In-Doped-CdS Cosensitized Quantum Dot Solar Cells

    Directory of Open Access Journals (Sweden)

    Lin Li

    2014-01-01

    Full Text Available Cu-doped-CdS and In-doped-CdS cosensitized (Cu-doped-CdS/In-doped-CdS quantum dot solar cells (QDSCs are introduced here. Different cosensitized sequences, doping ratios, and the thickness (SILAR cycles of Cu-doped-CdS and In-doped-CdS are discussed. Compared with undoped CdS QDSCs, the short circuit current density, UV-Vis absorption spectra, IPCE (monochromatic incident photon-to-electron conversion, open circuit voltage, and so on are all improved. The photoelectric conversion efficiency has obviously improved from 0.71% to 1.28%.

  1. Analysis of CdS/CdTe devices incorporating a ZnTe:Cu/Ti Contact

    International Nuclear Information System (INIS)

    Gessert, T.A.; Asher, S.; Johnston, S.; Young, M.; Dippo, P.; Corwine, C.

    2007-01-01

    High-performance CdS/CdTe photovoltaic devices can be produced using a ZnTe:Cu/Ti back contact deposited onto the CdTe layer. We observe that prolonged exposure of the ZnTe:Cu and Ti sputtering targets to an oxygen-containing plasma significantly reduces device open-circuit voltage and fill factor. High-resolution compositional analysis of these devices reveals that Cu concentration in the CdTe and CdS layers is lower for devices with poor performance. Capacitance-voltage analysis and related numerical simulations indicate that the net acceptor concentration in the CdTe is also lower for devices with poor performance. Photoluminescence analyses of the junction region reveal that the intensity of a luminescent peak associated with a defect complex involving interstitial Cu (Cu i ) and oxygen on Te (O Te ) is reduced in devices with poor performance. Combined with thermodynamic considerations, these results suggest that oxygen incorporation into the ZnTe:Cu sputtering target reduces the ability of sputtered ZnTe:Cu film to diffuse Cu into the CdTe

  2. Promising Cu-Ni-Cr-Si alloy for first wall ITER applications

    International Nuclear Information System (INIS)

    Ivanov, A.; Abramov, V.; Rodin, M.

    1996-01-01

    Precipitation-hardened Cu-Ni-Cr-Si alloy, a promising material for ITER applications, is considered. Available commercial products, chemical composition, physical and mechanical properties are presented. Embrittlement of Cu-Ni-Cr-Si alloy at 250-300 C is observed. Mechanical properties of Cu-Ni-Cr-Si alloy neutron irradiated to a dose of ∝0.2 dpa at 293 C are investigated. Embrittlement of Cu-Ni-Cr-Si alloy can be avoided by annealing. (orig.)

  3. Defect properties of CuCrO2: A density functional theory calculation

    International Nuclear Information System (INIS)

    Fang Zhi-Jie; Zhu Ji-Zhen; Zhou Jiang; Mo Man

    2012-01-01

    Using the first-principles methods, we study the formation energetics properties of intrinsic defects, and the charge doping properties of extrinsic defects in transparent conducting oxides CuCrO 2 . Intrinsic defects, some typical acceptor-type, and donor-type extrinsic defects in their relevant charge state are considered. By systematically calculating the formation energies and transition energy, the results of calculation show that, V Cu , O i , and O Cu are the relevant intrinsic defects in CuCrO 2 ; among these intrinsic defects, V Cu is the most efficient acceptor in CuCrO 2 . It is found that all the donor-type extrinsic defects have difficulty in inducing n-conductivity in CuCrO 2 because of their deep transition energy level. For all the acceptor-type extrinsic defects, substituting Mg for Cr is the most prominent doping acceptor with relative shallow transition energy levels in CuCrO 2 . Our calculation results are expected to be a guide for preparing promising n-type and p-type materials in CuCrO 2 . (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  4. Geographical and pedological drivers of distribution and risks to soil fauna of seven metals (Cd, Cu, Cr, Ni, Pb, V and Zn) in British soils

    International Nuclear Information System (INIS)

    Spurgeon, David J.; Rowland, Philip; Ainsworth, Gillian; Rothery, Peter; Long, Sara; Black, Helaina I.J.

    2008-01-01

    Concentrations of seven metals were measured in over 1000 samples as part of an integrated survey. Sixteen metal pairs were significantly positively correlated. Cluster analysis identified two clusters. Metals from the largest (Cr, Cu, Ni, V, Zn), but not the smallest (Cd, Pb) cluster were significantly negatively correlated with spatial location and soil pH and organic matter content. Cd and Pb were not correlated with these parameters, due possibly to the masking effect of recent extensive release. Analysis of trends with soil properties in different habitats indicated that general trends may not necessarily be applicable to all areas. A risk assessment indicated that Zn poses the most widespread direct risk to soil fauna and Cd the least. Any risks associated with high metal concentrations are, however, likely to be greatest in habitats such as arable and horticultural, improved grassland and built up areas where soil metal concentrations are more frequently elevated. - Metal distributions and risks explained by balance of sources and soil property effects on fate

  5. Geographical and pedological drivers of distribution and risks to soil fauna of seven metals (Cd, Cu, Cr, Ni, Pb, V and Zn) in British soils.

    Science.gov (United States)

    Spurgeon, David J; Rowland, Philip; Ainsworth, Gillian; Rothery, Peter; Long, Sara; Black, Helaina I J

    2008-05-01

    Concentrations of seven metals were measured in over 1000 samples as part of an integrated survey. Sixteen metal pairs were significantly positively correlated. Cluster analysis identified two clusters. Metals from the largest (Cr, Cu, Ni, V, Zn), but not the smallest (Cd, Pb) cluster were significantly negatively correlated with spatial location and soil pH and organic matter content. Cd and Pb were not correlated with these parameters, due possibly to the masking effect of recent extensive release. Analysis of trends with soil properties in different habitats indicated that general trends may not necessarily be applicable to all areas. A risk assessment indicated that Zn poses the most widespread direct risk to soil fauna and Cd the least. Any risks associated with high metal concentrations are, however, likely to be greatest in habitats such as arable and horticultural, improved grassland and built up areas where soil metal concentrations are more frequently elevated.

  6. Wear behavior of Cu-Ag-Cr alloy wire under electrical sliding

    International Nuclear Information System (INIS)

    Jia, S.G.; Liu, P.; Ren, F.Z.; Tian, B.H.; Zheng, M.S.; Zhou, G.S.

    2005-01-01

    The wear behavior of a Cu-Ag-Cr alloy contact wire against a copper-base sintered alloy strip was investigated. Wear tests were conducted under laboratory conditions with a special sliding wear apparatus that simulated train motion under electrical current conditions. The initial microstructure of the Cu-Ag-Cr alloy contact wire was analyzed by transmission electron microscopy. Worn surfaces of the Cu-Ag-Cr alloy wire were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The results indicate that the wear rate of the Cu-Ag-Cr wire increased with increasing electrical current and sliding. Within the studied range of electrical current, the wear rate increases with increasing electrical current and sliding speed. Compared with the Cu-Ag contact wire under the same testing conditions, the Cu-Ag-Cr alloy wire has much better wear resistance. Adhesive, abrasive, and electrical erosion wear are the dominant mechanisms during the electrical sliding processes

  7. Analysis of precipitation in a Cu-Cr-Zr alloy

    Institute of Scientific and Technical Information of China (English)

    Zhao Mei; Lin Guobiao; Wang Zidong; Zhang Maokui

    2008-01-01

    Precipites in Cu-0.42%Cr-0.21%Zr alloy were analyzed by using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDXS) and transmission electron microscope (TEM). After the solid solution was performed at 980℃ for 2 h, water-quenched and aged at 450℃ for 20 h, the precipite had a bimodal distribution of precipitate size. The coarse precipitates are pure Cr and Cu5Zr, the dispersed fine precipitate is CrCu2(Zr, Mg) and pure Cr ranging from 1 to 50 nm. The coarse phases formed during solidification and were left undissolved during solid solution. The fine precipitates are the hardening precipitates that form due to decomposition of the supersaturated solid solution during aging.

  8. Using precipitated Cr on the surface of Cu-Cr alloy powders as catalyst synthesizing CNTs/Cu composite powders by water-assisted CVD

    Science.gov (United States)

    Zhou, Honglei; Liu, Ping; Chen, Xiaohong; Bi, Liming; Zhang, Ke; Liu, Xinkuan; Li, Wei; Ma, Fengcang

    2018-02-01

    Given that the conventional catalyst is easily soluble in the matrix to result in the poor performance of the CNTs/Cu composite materials, the Cr nano-particles precipitated on the surface of Cu-Cr particles are first used as catalysts to prepare the CNTs/Cu composite powders by means of water-assisted chemical vapor deposition in situ synthesis. The results show that the morphological difference of the precipitated Cr nano-particle is obvious with the change of solution and aging treatment, and the morphology, length and diameter of the synthetic CNTs are also different. The catalyst of Cr nano-particle has the best morphology and the synthesized CNTs had a good wettability with Cu particles when the Cu-Cr composite powders was solution-treated at 1023 K for 60 min and then was aged at 723 K for 120 min. The length, diameter, yield and purity of the synthesized CNTs can be also affected by the moisture content in the reaction gas. It is the most suitable for the growth of CNTs when the moisture content is 0.4%, and the high purity and defect-free CNTs with the smooth pipe wall, a diameter of 20 ˜ 30 nm and a length of up to 1800 nm can be obtained. The yield of CNTs with the moisture content of 0.4% reached to 138%, which was increased by 119% to compare with that without moisture. In this paper, a feasible technology was offered for the preparation of high performance CNTs/Cu composites.

  9. Low-field spin dynamics of Cr7Ni and Cr7Ni-Cu -Cr 7Ni molecular rings as detected by μ SR

    Science.gov (United States)

    Sanna, S.; Arosio, P.; Bordonali, L.; Adelnia, F.; Mariani, M.; Garlatti, E.; Baines, C.; Amato, A.; Sabareesh, K. P. V.; Timco, G.; Winpenny, R. E. P.; Blundell, S. J.; Lascialfari, A.

    2017-11-01

    Muon spin rotation measurements were used to investigate the spin dynamics of heterometallic Cr7Ni and Cr7Ni -Cu-Cr7Ni molecular clusters. In Cr7Ni the magnetic ions are arranged in a quasiplanar ring and interact via an antiferromagnetic exchange coupling constant J , while Cr7Ni -Cu-Cr7Ni is composed of two Cr7Ni linked by a bridging moiety containing one Cu ion, that induces an inter-ring ferromagnetic interaction J'≪J . The longitudinal muon relaxation rate λ collected at low magnetic fields μ0H BPP)-like heuristic fitting model that takes into account of a distribution of electronic spin characteristic times for T >5 K, while the shoulder presented by Cr7Ni can be reproduced by a BPP function that incorporates a single electronic characteristic time theoretically predicted to dominate for T <5 K. The flattening of λ (T ) in Cr7Ni -Cu-Cr7Ni occurring at very low temperature can be tentatively attributed to field-dependent quantum effects and/or to an inelastic term in the spectral density of the electronic spin fluctuations.

  10. Relaxation of magnetization in spinel CuCrZrS4

    International Nuclear Information System (INIS)

    Ito, Masakazu; Furuta, Tatsuya; Terada, Norio; Ebisu, Shuji; Nagata, Shoichi

    2012-01-01

    We studied time t dependence of magnetization M(t) of thiospinel CuCrZrS 4 which has a spin-glass freezing. The relaxation of M is observed below T f ≃6K and shows a logarithmic time dependence. This means that a relaxation time τ of CuCrZrS 4 is distributed in a wide time range. Randomness of an arrangement of the Cr and Zr ions in CuCrZrS 4 probably gives rise to a distribution of τ. Temperature T dependence of magnetic viscosity β(T) is understood by a conventional after-effect model with a box-type distribution function of τ.

  11. Ostwald ripening of decomposed phases in Cu-Ni-Cr alloys

    International Nuclear Information System (INIS)

    Hernandez-Santiago, Felipe; Lopez-Hirata, Victor; Dorantes-Rosales, Hector J.; Saucedo-Munoz, Maribel L.; Gonzalez-Velazquez, Jorge L.; Paniagua-Mercado, Ana Ma.

    2008-01-01

    A study of the coarsening process of the decomposed phases was carried out in the Cu-34 wt.% Ni-4 wt.% Cr and Cu-45 wt.% Ni-10 wt.% Cr alloys using transmission electron microscopy. As aging progressed, the morphology of the coherent decomposed Ni-rich phase changed from cuboids to platelets aligned in the Cu-rich matrix directions. Prolonged aging caused the loss of coherency between the decomposed phases and the morphology of the Ni-rich phase changed to ellipsoidal. The variation of mean radius of the coherent decomposed phases with aging time followed the modified LSW theory for thermally activated growth in ternary alloy systems. The linear variation of the density number of precipitates and matrix supersaturation with aging time, also confirmed that the coarsening process followed the modified LSW theory in both alloys. The coarsening rate was faster in the symmetrical Cu-45 wt.% Ni-10 wt.% Cr alloy due to its higher volume fraction of precipitates. The activation energy for thermally activated growth was determined to be about 182 and 102 kJ mol -1 in the Cu-34 wt.% Ni-4 wt.% Cr and Cu-45 wt.% Ni-10 wt.% Cr alloys, respectively. The lower energy for the former alloy seems to be related to an increase in the atomic diffusion process as the chromium content increases. The size distributions of precipitates in the Cu-Ni-Cr alloys were broader and more symmetric than that predicted by the modified LSW theory for ternary alloys

  12. Enhancing the CuCrZr/316L HIP-joint by Ni electroplating

    Energy Technology Data Exchange (ETDEWEB)

    Wei, R. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Science Island Branch of Graduate School, University of Science & Technology of China, Hefei, 230031 (China); Zhao, S.X., E-mail: sxzhao@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Science, Lanzhou, 730000 (China); Dong, H.; Che, H.Y. [Advanced Technology and Materials Co. Ltd., Beijing, 100081 (China); Li, Q.; Wang, W.J.; Wang, J.C.; Wang, X.L.; Sun, Z.X. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Luo, G.-N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Science Island Branch of Graduate School, University of Science & Technology of China, Hefei, 230031 (China); Hefei Center for Physical Science and Technology, Hefei, 230022 (China); Hefei Science Center of Chinese Academy of Sciences, Hefei, 230027 (China)

    2017-04-15

    Highlights: • The quality of CuCrZr/316L HIP-joint can be enhanced by nickel electroplating on CuCrZr and 316L. • Nickel layer can prevent the occurrence of nickel-poor region in 316L and protect CuCrZr from oxidation. • A Charpy Impact Value as high as 111.5 ± 3.3 J/cm{sup 2} can be obtained by HIP at 980 °C, 140 MPa for 2 h. • At high temperature, CuCrZr is easily oxidized even in the situation of a high vacuum degree of 2 × 10{sup −5} Pa. - Abstract: The quality of CuCrZr/316L joint is crucial for the safety of ITER hypervapotron cooling structure and hot isostatic pressing (HIP) is an important bonding technique for this structure. In this paper, the authors present a finding that the CuCrZr/316L HIP-joint can be enhanced by nickel electroplating on 316L and CuCrZr. A Charpy Impact Value as high as 111.5 ± 3.3 J/cm{sup 2}, which is more than two times the value in a published article, is obtained. The influence of nickel electroplating is twofold: (1) it can prevent the occurrence of nickel-poor region in 316L and the formation of ferrite; (2) it can protect CuCrZr from oxidation during the heating stage of HIP. However, tensile test is not as effective as Charpy Impact Test in characterizing the bonding quality of the CuCrZr/316L HIP-joint. The surface treatment employed in this study is amenable to batch-scale industrial manufacturing at low cost.

  13. Associations between standardized school performance tests and mixtures of Pb, Zn, Cd, Ni, Mn, Cu, Cr, Co, and V in community soils of New Orleans

    International Nuclear Information System (INIS)

    Zahran, Sammy; Mielke, Howard W.; Weiler, Stephan; Hempel, Lynn; Berry, Kenneth J.; Gonzales, Christopher R.

    2012-01-01

    In New Orleans a strong inverse association was previously identified between community soil lead and 4th grade school performance. This study extends the association to zinc, cadmium, nickel, manganese, copper, chromium, cobalt, and vanadium in community soil and their comparative effects on 4th grade school performance. Adjusting for poverty, food security, racial composition, and teacher-student ratios, regression results show that soil metals variously reduce and compress student scores. Soil metals account for 22%–24% while food insecurity accounts for 29%–37% of variation in school performance. The impact on grade point averages were Ni > Co > Mn > CuCrCd > Zn > Pb, but metals are mixtures in soils. The quantities of soil metal mixtures vary widely across the city with the largest totals in the inner city and smallest totals in the outer city. School grade point averages are lowest where the soil metal mixtures and food insecurity are highest. - Highlights: ► Mixtures of metals vary; largest totals in the inner city and lowest in the outer city. ► An inverse association between soil Pb and 4th grade school performance is known. ► Assuming the same exposure pathway, multiple metals are compared to performance. ► Soil metals account for 22%–24% of variation in school test performance. ► Soil metal plus food insecurity accounts for 54% of explained variance. - Controlling for potential confounding variables, the accumulation of metals (Pb, Zn, Cd, Ni, Mn, Cu, Cr, and Co) in neighborhood soils is significantly negatively associated with 4th grade school performance on standardized tests in New Orleans.

  14. Thermodynamic properties of CdCr2S4

    International Nuclear Information System (INIS)

    Kesler, Ya.A.; Shchelkotunov, V.A.; Tret'yakov, Yu.D.; Kamyshova, V.K.; Gordeev, I.V.; Alferov, V.A.

    1977-01-01

    The true thermal capacity of ferromagnetic chromium spinel CdCr 2 S 4 has been measured in the temperature range of 172-673 K. Coefficient of linear expansion has been measured in the temperature range of 173-677 K. A change in heat content of the compound has been found by the mixing method (298-750 K). The lattice contribution into thermal capacity, the contribution of thermal expansion, the values of isothermal compressibility factor, and the Crueneisen constants have been calculated from true and mean heat capacity of CdCr 2 S 4 in a wide temperature range. The lattice energy V has been calculated for CdCr 2 S 4 ; it amounts -4226 kcal/mol

  15. NMR of Cu satellites in the Kondo alloy CuCr

    International Nuclear Information System (INIS)

    Azevedo, L.J.; Follstaedt, D.; Narath, A.

    1978-01-01

    Using pulsed NMR techniques, resonances of Cu nuclei which are near neighbors to Cr impurities (c = 100 and 200 ppM) in CuCr (theta/sub k/ approx. 3K) have been studied in the temperature range 1 to 4K and applied fields H 0 = 20 to 125 kOe. At the highest fields and lowest temperatures the satellite shifts approach saturation. Above approx. 40 kOe the spin-lattice relaxation rate T 1 -1 is proportional to T/H 0 2 , indicating that the dominant relaxation mechanism arises from transverse fluctuations of a polarized local moment. The measured rates yield a local-moment/conduction-electron exchange interaction vertical bar J 0 vertical bar/g = 0.30, where g is the Cr g-value. Below approx. 40 kOe T 1 -1 appears to be slightly enhanced in comparison with the high-field behavior, but becomes field independent below approx. 30 kOe. Both effects are attributed to Kondo anomalies

  16. Quantitative Characterization of the Toxicities of Cd-Ni and Cd-Cr Binary Mixtures Using Combination Index Method

    Directory of Open Access Journals (Sweden)

    Lingyun Mo

    2016-01-01

    Full Text Available Direct equipartition ray design was used to construct Cd-Ni and Cd-Cr binary mixtures. Microplate toxicity analysis was used to evaluate the toxicity of individual substance and the Cd-Ni and Cd-Cr mixtures on Chlorella pyrenoidosa and Selenastrum capricornutum. The interacting toxicity of the mixture was analyzed with concentration addition (CA model. In addition, combination index method (CI was proposed and used to quantitatively characterize the toxicity of the binary mixtures of Cd-Ni and Cd-Cr observed in experiment and find the degree of deviation from the predicted outcome of the CA model, that is, the intensity of interacting toxicity. Results indicate that most of the 20 binary mixtures exhibit enhancing and synergistic effect, and only Cd-Cr-R4 and Cd-Cr-R5 mixtures have relatively high antagonistic effects against C. pyrenoidosa. Based on confidence interval, CI can compare the intensities of interaction of the mixtures under varying levels of effect. The characterization methods are applicable for analyzing binary mixture with complex interaction.

  17. Preparation of W/CuCrZr monoblock test mock-up using vacuum brazing technique

    International Nuclear Information System (INIS)

    Singh, Kongkham Premjit; Khirwadkar, Samir S.; Bhope, Kedar; Patel, Nikunj; Mokaria, Prakash K.; Mehta, Mayur

    2015-01-01

    Development of the joining for W/CuCrZr monoblock PFC test mock-up is an interest area in Fusion R and D. W/Cu bimetallic material has prepared using OFHC copper casting approach on the radial surface of W monoblock tile surface. The W/Cu bimetallic material has been joined with CuCrZr tube (heat sink) material with the vacuum brazing route. Vacuum brazing of W/Cu-CuCrZr has been performed @ 970 °C for 10 mins using NiCuMn-37 filler material under deep vacuum environment (10 -6 mbar). Graphite fixtures were used for OFHC copper casting and vacuum brazing experiments. The joint integrity of W/Cu-CuCrZr monoblock mock-up on W/Cu and Cu-CuCrZr has been checked using ultrasonic immersion technique. Micro-structural examination and Spot-wise elemental analysis have been carried out using HR-SEM and EDAX. The results of the experimental work will be discussed in the paper. (author)

  18. Quasicrystalline and crystalline phases in Al65Cu20(Fe, Cr)15 alloys

    International Nuclear Information System (INIS)

    Liu, W.; Koester, U.; Mueller, F.; Rosenberg, M.

    1992-01-01

    Two types of icosahedral quasicrystals are observed in Al 65 Cu 20 Fe 15-x Cr x (0 ≤ x ≤ 15) alloys, the face-centred AlCuFe-type icosahedral phase with dissoluted Cr and the primitive AlCuCr-type icosahedral phase with dissoluted Fe. In the vicinity of Al 65 Cu 20 Fe 8 Cr 7 a stable decagonal phase (a=0.45 nm and c=1.23 nm) forms competitively with the icosahedral quasicrystals. All these three quasicrystalline phases can be regarded as Hume-Rothery phases stabilized by the energy band factor. The density is measured to be 4.57, 4.44, and 4.11 g/cm 3 for the icosahedral Al 65 Cu 20 Fe 15 , the decagonal Al 65 Cu 20 Fe 8 Cr 7 , and the icosahedral Al 65 Cu 20 Cr 15 alloys, respectively. Depending on the composition in the range between Al 65 Cu 20 Fe 8 Cr 7 and Al 65 Cu 20 Cr 15 , several crystalline phases are observed during the transormation of the AlCuCr-type icosahedral phase: the 1/1-3/2-type orthorhombic (o) and the 1/0-3/2-type tetragonal (t) approximants of the decagonal phase, a hexagonal (h) phase, as well as a long-range vacancy ordered τ 3 -phase derived from a CsCl-type structure with a=0.2923 nm. The structures of all the crystalline phases are closely related to those of the icosahedral (i) and decagonal (d) quasicrystals, which leads to a definite orientation relationship as follows: i5 parallel d10 parallel o[100] parallel t[100] parallel h[001] parallel τ 3 [110]. (orig.)

  19. The effect of Cu on the properties of CdO/Cu/CdO multilayer films for transparent conductive electrode applications

    Energy Technology Data Exchange (ETDEWEB)

    Raaif, M.; Mohamed, S.H. [Sohag University, Physics Department, Faculty of Science, Sohag (Egypt)

    2017-06-15

    Transparent conductive CdO/Cu/CdO multilayer films were prepared using rf plasma magnetron sputtering and electron beam evaporation techniques. The CdO layers were prepared using rf plasma magnetron sputtering, while the Cu interlayer was prepared by electron beam evaporation technique. The Cu layer thickness was varied between 1 and 10 nm. The structural and optical properties as well as the sheet resistance of the multilayer films were studied. X-ray diffraction measurements revealed the presence of cubic CdO structure and the Cu peak was only observed for the multilayers prepared with 10 nm of Cu. It has been observed that the Cu interlayer thickness has a great influence on the optical and electrical properties of the multilayers. The transmittance of the multilayer films decreased while the reflectance increased with increasing Cu interlayer thickness. The refractive index and the extinction coefficient of the multilayer films were calculated. The estimated optical band gap values were found to be decreased from 2.75 ± 0.02 to 2.40 ± 0.02 eV as the Cu interlayer thickness increased from 1 to 10 nm. The sheet resistance was sensitive to the Cu interlayer thickness and it decreased with increasing Cu interlayer thickness. A sheet resistSSance of 21.7 Ω/sq, an average transmittance (between 700 and 1000 nm) of 77%, and an optical band gap of 2.5 ± 0.02 eV were estimated for the multilayer film with 2 nm Cu layer. The multilayer film with 2 nm Cu layer has the highest figure of merit value of 3.2 x 10{sup -3} Ω{sup -1}. This indicates that the properties of this multilayer film are suitable for transparent conductive electrode applications. (orig.)

  20. First-principles-based analysis of the influence of Cu on CdTe electronic properties

    International Nuclear Information System (INIS)

    Krasikov, D.; Knizhnik, A.; Potapkin, B.; Selezneva, S.; Sommerer, T.

    2013-01-01

    The maximum voltage of CdTe solar cells is limited by low majority carrier concentration and doping difficulty. Copper that enters from the back contact can form both donors and acceptors in CdTe. It is empirically known that the free carrier concentration is several orders lower than the total Cu concentration. Simplified thermodynamic models of defect compensation after Cu introduction can be found in literature. We present a first-principles-based analysis of kinetics of defect formation upon Cu introduction, and show that Cu i is mobile at room temperature. Calculations of properties of Cu i –V Cd and Cu i –Cu Cd complexes show that the neutral Cu i –Cu Cd complex is mobile at elevated temperatures, while formation of the V CdCu i complex is unlikely because it transforms into the Cu Cd defect. - Highlights: ► First-principles calculations of copper defects in CdTe are performed. ► Formation of Cd vacancy + Cu interstitial(Cu i ) complex is unlikely. ► Cu i defect is mobile at room temperature. ► Cu i + Cu on Cd-site (Cu Cd ) complex is mobile at elevated temperature. ► Cu Cd defect forms by kicking-out of the regular lattice Cd by Cu i

  1. Cu-Doping Effects in CdI(2) Nanocrystals: The Role of Cu-Agglomerates.

    Science.gov (United States)

    Miah, M Idrish

    2008-11-22

    Cu-doping effects in CdI(2) nanocrystals are studied experimentally. We use the photostimulated second harmonic generation (PSSHG) as a tool to investigate the effects. It is found that the PSSHG increases with increasing Cu content up to 0.6% and then decreases due to the formation of the Cu-agglomerates. The PSSHG for the crystal with Cu content higher than 1% reduces to that for the undoped CdI(2) crystal. The results suggest that a crucial role of the Cu-metallic agglomerates is involved in the processes as responsible for the observed effects.

  2. Cu-Doping Effects in CdI2Nanocrystals: The Role of Cu-Agglomerates

    Directory of Open Access Journals (Sweden)

    Miah M

    2008-01-01

    Full Text Available Abstract Cu-doping effects in CdI2nanocrystals are studied experimentally. We use the photostimulated second harmonic generation (PSSHG as a tool to investigate the effects. It is found that the PSSHG increases with increasing Cu content up to 0.6% and then decreases due to the formation of the Cu-agglomerates. The PSSHG for the crystal with Cu content higher than 1% reduces to that for the undoped CdI2crystal. The results suggest that a crucial role of the Cu-metallic agglomerates is involved in the processes as responsible for the observed effects.

  3. Investigation of Cu-poor and Cu-rich Cu(In,Ga)Se{sub 2}/CdS interfaces using hard X-ray photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ümsür, B., E-mail: buenyamin.uemsuer@helmholtz-berlin.de [Helmholtz-Zentrum-Berlin, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Calvet, W.; Höpfner, B.; Steigert, A.; Lauermann, I.; Gorgoi, M.; Prietzel, K.; Navirian, H.A.; Kaufmann, C.A.; Unold, T. [Helmholtz-Zentrum-Berlin, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Lux-Steiner, M. Ch. [Helmholtz-Zentrum-Berlin, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Freie Universität Berlin, Department of Physics, Arnimallee 14, D-14195 Berlin (Germany)

    2015-05-01

    Cu-poor and Cu-rich Cu(In,Ga)Se{sub 2} (CIGSe) absorbers were used as substrates for the chemical bath deposition of ultrathin CdS buffer layers in the thickness range of a few nanometers in order to make the CIGSe/CdS interface accessible by hard X-ray photo-emission spectroscopy. The composition of both, the absorber and the buffer layer as well as the energetics of the interface was investigated at room temperature and after heating the samples to elevated temperatures (200 °C, 300 °C and 400 °C). It was found that the amount of Cd after the heating treatment depends on the near surface composition of the CIGSe absorber. No Cd was detected on the Cu-poor surface after the 400 °C treatment due to its diffusion into the CIGSe layer. In contrast, Cd was still present on the Cu-rich surface after the same treatment at 400 °C. - Highlights: • Cd diffusion into Cu(In,Ga)Se{sub 2} (CIGSe) absorber is investigated. • Cu-poor and Cu-rich CIGSe samples are compared. • Cd diffusion into CIGSe is found to be dependent on the surface composition of CIGSe.

  4. Revealing the Microstructural evolution in Cu-Cr nanocrystalline alloys during high pressure torsion

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jinming; Rosalie, Julian M.; Pippan, Reinhard; Zhang, Zaoli, E-mail: zaoli.zhang@oeaw.ac.at

    2017-05-17

    Usually immiscible Cu-Cr compounds in equilibrium condition were mechanically processed via high pressure torsion with large and controlled strains. A systematical investigation on 57 wt%Cu − 43 wt%Cr was carried out to get insights into the microstructural evolution of Cu-Cr nanocomposites and their dissolution process, as well as to determine the solid solubility limit of Cu and Cr elements under severe deformation. Microstructural evolution was captured with grain refinement from micron-size down to less than 20 nm as the increase of strains. A strain-saturated state in 57 wt%Cu − 43 wt%Cr bulk was achieved after 100 rotations deformation (effective strain 1360), with a stable grain size of 13.7 nm and invariable hardness of 480–495 HV. Fine scanning of X-ray diffraction and sub-nanometer scale measurements of energy-dispersive X-ray spectroscopy showed that 32 wt% Cu could be fully dissolved into Cr matrix, and conversely solubility of Cr in Cu was determined to be about 3 wt% after an enough amount of deformation. The phase fraction change associated with Cu dissolution into Cr matrix during continuous deformation was captured and accurately calculated, indicating a negative exponential phase change mode. A phenomenological intermixing mechanism based on the kinetic competition between external forcing mixing and thermal-diffusion induced decomposition was proposed, which was well accordant with the phase evolution observed from experimental results.

  5. 53Cr NMR study of CuCrO2 multiferroic

    Science.gov (United States)

    Smol'nikov, A. G.; Ogloblichev, V. V.; Verkhovskii, S. V.; Mikhalev, K. N.; Yakubovskii, A. Yu.; Kumagai, K.; Furukawa, Y.; Sadykov, A. F.; Piskunov, Yu. V.; Gerashchenko, A. P.; Barilo, S. N.; Shiryaev, S. V.

    2015-11-01

    The magnetically ordered phase of the CuCrO2 single crystal has been studied by the nuclear magnetic resonance (NMR) method on 53Cr nuclei in the absence of an external magnetic field. The 53Cr NMR spectrum is observed in the frequency range νres = 61-66 MHz. The shape of the spectrum depends on the delay tdel between pulses in the pulse sequence τπ/2- t del-τπ- t del-echo. The spin-spin and spin-lattice relaxation times have been measured. Components of the electric field gradient, hyperfine fields, and the magnetic moment on chromium atoms have been estimated.

  6. Preliminary study of CdTe and CdTe:Cu thin films nanostructures deposited by using DC magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Marwoto, Putut; Made, D. P. Ngurah; Sugianto [Departement of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia); Wibowo, Edy; Astuti, Santi Yuli; Aryani, Nila Prasetya [Materials Research Group, Laboratory of Thin Film, Department of Physics, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia); Othaman, Zulkafli [Departement of Physics, Universiti Teknologi Malaysia (UTM), Skudai, Johor Bahru (Malaysia)

    2013-09-03

    Growth and properties of CdTe and CdTe:Cu thin films nanostrucures deposited by using dc magnetron sputtering are reported. Scanning electron microscope (SEM) was used to observe the surface morphologies of the thin films. At growth conditions of 250 °C and 14 W, CdTe films did not yet evenly deposited. However, at growth temperature and plasma power of 325 °C and 43 W, both CdTe and CdTe:Cu(2%) have deposited on the substrates. In this condition, the morphology of the films indicate that the films have a grain-like nanostructures. Grain size diameter of about 200 nm begin to appear on top of the films. Energy Dispersive X-rays spectroscopy (EDX) was used to investigate chemical elements of the Cu doped CdTe film deposited. It was found that the film deposited consist of Cd, Te and Cu elements. XRD was used to investigate the full width at half maximum (FWHM) values of the thin films deposited. The results show that CdTe:Cu(2%) thin film has better crystallographic properties than CdTe thin film. The UV-Vis spectrometer was used to investigate the optical properties of thin films deposited. The transmittance spectra showed that transmittance of CdTe:Cu(2%) film is lower than CdTe film. It was found that the bandgap energy of CdTe and CdTe:Cu(2%) thin films of about 1.48 eV.

  7. Distribution of POC, PON and particulate Al, Cd, Cr, Cu, Pb, Ti, Zn and δ13C in the English Channel and adjacent areas

    International Nuclear Information System (INIS)

    Dauby, P.; Frankignoulle, M.; Gobert, S.; Bouquegneau, J.M.

    1994-01-01

    A study of the spatial distribution of the total suspended matter and of its elemental composition (C, N and trace metals) has been performed in the English Channel. The Celtic Sea, and the Southern Bight of the North Sea in June and October 1991. South-west to north-east gradients of suspended matter mass and of lithogenic components (Ti an Al) linked to riverine inputs and to depth shallowing, are observed; organic carbon and nitrogen display an opposite distribution pattern and reach a maximum in the Biscay oceanic waters. Cu, Pb and Zn concentrations are highest near industrialized areas and large estuaries, showing the importance of river inputs. In contrast, Cd, Cu and Cr concentrations are markedly elevated in organic-rich suspended matter from waters in which suspended matter loadings are low, suggesting a significant biological uptake. Finally, 13 C/ 12 C analyses reveal the relative importance of coastal or continental inputs in the north-eastern Channel and in the North Sea. (authors). 56 refs., 12 figs., 3 tabs

  8. Effect of HIP temperature on microstructure and low cycle fatigue strength of CuCrZr alloy

    Science.gov (United States)

    Nishi, Hiroshi; Enoeda, Mikio

    2011-10-01

    In order to investigate the effect of the HIP cycle temperatures on the metallurgic degradation and the mechanical properties of CuCrZr alloy, assessments of the microstructure, tensile test, Charpy impact test and low cycle fatigue test are performed for various heat treated CuCrZr alloys, which were solution-annealed followed by water-quenched and aged state of CuCrZr with simulated HIP cycle at temperatures of 980 and 1045 °C. Grain growth occurred on 1045 °C HIP CuCrZr, though slightly on 980 °C HIP CuCrZr. Metallurgic degradation such as voids was not found by optical and SEM observations. There were coarse precipitates in all the CuCrZr and the precipitates did not easily dissolve at 980 °C. The low cycle fatigue strength of 1045 °C HIP CuCrZr was lower than that of other CuCrZr because of the metallurgic degradation caused by the heat cycle, while that of other CuCrZr was corresponding to the best fit curve of ITER MPH.

  9. Effect of HIP temperature on microstructure and low cycle fatigue strength of CuCrZr alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nishi, Hiroshi, E-mail: nishi.hiroshi88@jaea.go.jp [Japan Atomic Energy Agency, Naka-shi, Ibaraki-ken 311-0193 (Japan); Enoeda, Mikio [Japan Atomic Energy Agency, Naka-shi, Ibaraki-ken 311-0193 (Japan)

    2011-10-01

    In order to investigate the effect of the HIP cycle temperatures on the metallurgic degradation and the mechanical properties of CuCrZr alloy, assessments of the microstructure, tensile test, Charpy impact test and low cycle fatigue test are performed for various heat treated CuCrZr alloys, which were solution-annealed followed by water-quenched and aged state of CuCrZr with simulated HIP cycle at temperatures of 980 and 1045 deg. C. Grain growth occurred on 1045 deg. C HIP CuCrZr, though slightly on 980 deg. C HIP CuCrZr. Metallurgic degradation such as voids was not found by optical and SEM observations. There were coarse precipitates in all the CuCrZr and the precipitates did not easily dissolve at 980 deg. C. The low cycle fatigue strength of 1045 deg. C HIP CuCrZr was lower than that of other CuCrZr because of the metallurgic degradation caused by the heat cycle, while that of other CuCrZr was corresponding to the best fit curve of ITER MPH.

  10. Effect of HIP temperature on microstructure and low cycle fatigue strength of CuCrZr alloy

    International Nuclear Information System (INIS)

    Nishi, Hiroshi; Enoeda, Mikio

    2011-01-01

    In order to investigate the effect of the HIP cycle temperatures on the metallurgic degradation and the mechanical properties of CuCrZr alloy, assessments of the microstructure, tensile test, Charpy impact test and low cycle fatigue test are performed for various heat treated CuCrZr alloys, which were solution-annealed followed by water-quenched and aged state of CuCrZr with simulated HIP cycle at temperatures of 980 and 1045 deg. C. Grain growth occurred on 1045 deg. C HIP CuCrZr, though slightly on 980 deg. C HIP CuCrZr. Metallurgic degradation such as voids was not found by optical and SEM observations. There were coarse precipitates in all the CuCrZr and the precipitates did not easily dissolve at 980 deg. C. The low cycle fatigue strength of 1045 deg. C HIP CuCrZr was lower than that of other CuCrZr because of the metallurgic degradation caused by the heat cycle, while that of other CuCrZr was corresponding to the best fit curve of ITER MPH.

  11. HIP joining of Be/CuCrZr for fabrication of ITER first wall

    International Nuclear Information System (INIS)

    Park, Jeong-Yong; Choi, Byung-Kwon; Park, Sang-Yoon; Kim, Hyun-Gil; Kim, Jun-Hwan; Hong, Bong Guen; Jeong, Yong Hwan

    2007-01-01

    The effects of different interlayer types and the temperature have been investigated in order to optimize the HIP joining conditions of Be to CuCrZr. Ti/Cu and Cr/Cu interlayers were coated onto a Be surface before a HIP joining. HIP temperature was changed from 580 to 620 deg. C. No intermetallic compounds or defects were formed at the interface of the joint specimens. The joining strength measured by the four-point bend test and the shear test was higher in the joint specimen with Ti/Cu interlayers when compared to that with Cr/Cu interalyers and it was increased with an increase of the HIP temperature from 580 to 620 deg. C. The yield strength of the aged CuCrZr was higher than 150 MPa at 250 deg. C up to an aging temperature of 620 deg. C after a water quenching. It is therefore suggested that the HIP temperature of the Be/CuCrZr joint could be increased to 620 deg. C based on the results obtained from this study

  12. Characterization of transparent superconductivity Fe-doped CuCrO{sub 2} delafossite oxide

    Energy Technology Data Exchange (ETDEWEB)

    Taddee, Chutirat [Materials Science and Nanotechnology Program, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Kamwanna, Teerasak, E-mail: teekam@kku.ac.th [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Khon Kaen University, Khon Kaen 40002 (Thailand); Amornkitbamrung, Vittaya [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Khon Kaen University, Khon Kaen 40002 (Thailand)

    2016-09-01

    Graphical abstract: - Highlights: • Effect of Fe substitution on the physical properties in CuCrO{sub 2} is studied. • The substitution of Cr{sup 3+} by Fe{sup 3+} produces a mixed effect on the magnetic properties. • CuCr{sub 1−x}Fe{sub x}O{sub 2} delafossite oxides show transparent superconductivity. - Abstract: Delafossite CuCr{sub 1−x}Fe{sub x}O{sub 2} (0.0 ≤ x ≤ 0.15) semiconductors were synthesized using a self-combustion urea nitrate process. The effects of Fe concentration on its microstructural, optical, magnetic, and electrical properties were investigated. X-ray diffraction (XRD) analysis results revealed the delafossite structure in all the samples. The lattice spacing of CuCr{sub 1−x}Fe{sub x}O{sub 2} slightly increased with increasing substitution of Fe at the Cr sites. The optical properties measured at room temperature using UV–visible spectroscopy showed a weak absorbability in the visible light and near IR regions. The corresponding direct optical band gap was about 3.61 eV, exhibiting transparency in the visible region. The magnetic hysteresis loop measurements showed that the Fe-doped CuCrO{sub 2} samples exhibited ferromagnetic behavior at room temperature. This indicated that the substitution of Fe{sup 3+} for Cr{sup 3+} produced a mixed effect on the magnetic properties of CuCrO{sub 2} delafossite oxide. The temperature dependent resistivity measurements clearly revealed the presence of superconductivity in the CuCr{sub 1−x}Fe{sub x}O{sub 2} with a superconducting transition up to 118 K.

  13. Axial strain localization of CuCrZr tubes during manufacturing of ITER-like mono-block W/Cu components using HIP

    International Nuclear Information System (INIS)

    Zhao, S.X.; Peng, L.J.; Li, Q.; Wang, W.J.; Wei, R.; Qin, S.G.; Shi, Y.L.; Chang, S.P.; Xu, Y.; Liu, G.H.; Wang, T.J.; Luo, G.-N.

    2014-01-01

    Highlights: • Axial cracking and denting of CuCrZr tubes were observed. • Annealing the as-received tubes can alleviate cracking. • Denting results in the formation bonding flaws at the Cu/CuCrZr interfaces. - Abstract: Two forms of axial strain localization of CuCrZr tubes, i.e., cracking and denting, were observed during the manufacturing of ITER-like mono-block W/Cu components for EAST employing hot isostatic pressing (HIP). Microscopic investigations indicate that the occurrence of axial strain localization correlates to the heavily deformed Cu grains and elongated Cr-rich precipitates as well as highly anisotropic microstructures, which impair the circumferential ductility. Annealing the as-received tubes at 600 °C alleviates cracking due to partial recrystallization of Cu grains. However, the annealed tubes are still sensitive to wall thinning (caused by non-uniform polishing or tube bending), which results in denting. Denting may cause bonding flaws at CuCrZr/Cu interfaces and the underlying mechanisms are discussed. To some extent, denting seems do not affect the high heat flux performance of components. In this paper, we demonstrate that testing only the axial mechanical properties is not enough for manufacturers who use HIP or hot radial pressing technologies, especially for those anisotropic tubes

  14. Succulent species differ substantially in their tolerance and phytoextraction potential when grown in the presence of Cd, Cr, Cu, Mn, Ni, Pb, and Zn.

    Science.gov (United States)

    Zhang, Chengjun; Sale, Peter W G; Clark, Gary J; Liu, Wuxing; Doronila, Augustine I; Kolev, Spas D; Tang, Caixian

    2015-12-01

    Plants for the phytoextraction of heavy metals should have the ability to accumulate high concentrations of such metals and exhibit multiple tolerance traits to cope with adverse conditions such as coexistence of multiple heavy metals, high salinity, and drought which are the characteristics of many contaminated soils. This study compared 14 succulent species for their phytoextraction potential of Cd, Cr, Cu, Mn, Ni, Pb, and Zn. There were species variations in metal tolerance and accumulation. Among the 14 succulent species, an Australian native halophyte Carpobrotus rossii exhibited the highest relative growth rate (20.6-26.6 mg plant(-1) day(-1)) and highest tolerance index (78-93%), whilst Sedum "Autumn Joy" had the lowest relative growth rate (8.3-13.6 mg plant(-1) day(-1)), and Crassula multicava showed the lowest tolerance indices (phytoextraction of these heavy metals than other species. These findings suggest that Carpobrotus rossii is a promising candidate for phytoextraction of multiple heavy metals, and the aquatic or semiterrestrial Crassula helmsii is suitable for phytoextraction of Cd and Zn from polluted waters or wetlands.

  15. Magnetic and transport properties of Cu1.05Cr0.89 Mg0.05O2 and Cu0.96Cr0.95 Mg0.05Mn0.04O2 films

    International Nuclear Information System (INIS)

    Xu Qingyu; Schmidt, Heidemarie; Zhou Shengqiang; Potzger, Kay; Helm, Manfred; Hochmuth, Holger; Lorenz, Michael; Meinecke, Christoph; Grundmann, Marius

    2008-01-01

    We prepared conductive, polycrystalline or amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 films on a-plane sapphire substrates by pulsed laser deposition under different O 2 partial pressure and substrate temperature. Hall measurements were performed to study the majority carrier type in these films. Polycrystalline Cu 1.05 Cr 0.89 Mg 0.05 O 2 is n-type conducting at 290 K, while in amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 the type of majority charge carriers changes from electrons to holes at around 270 K. Interestingly, the structure has little influence on the magnetic properties of the films. A clear antiferromagnetic to paramagnetic transition was observed in both polycrystalline and amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 films at 25 K. Similar electrical properties to Cu 1.05 Cr 0.89 Mg 0.05 O 2 film were observed for Cu 0.96 Cr 0.95 Mg 0.05 Mn 0.04 O 2 in dependence on the structure, while only paramagnetic without antiferromagnetic ordering was observed down to 5 K. Large negative magnetoresistance of 27% at 20 K was observed at 6 T in amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 film

  16. Anti-wetting Cu/Cr coating with micro-posts array structure fabricated by electrochemical approaches

    International Nuclear Information System (INIS)

    Zhou, Yufeng; Hang, Tao; Li, Feng; Li, Ming

    2013-01-01

    Microposts structured Cu/Cr multilayer coating was prepared by a simple two-step approach combining electroless and electro deposition. Surface morphologies of the as-prepared Cu/Cr multilayer coating characterized by field emission scanning electron microscopy show that this multilayer coating exhibits micro-posts arrayed structure with a layer of Cr uniformly covering the circular conical surface of Cu micro-cones array. The wettability test shows that the contact angle of Cu/Cr multilayer surface with water drop can be greater than 140° by optimizing the electrodeposition time of Cr. The mechanism of hydrophobicity of both the micro-cones arrayed and micro-posts arrayed structures was briefly discussed by comparing two different wetting modes. Due to its good anti-wetting property and unique structure, the micro-posts arrayed Cu/Cr multilayer coating is expected for extensive practical applications.

  17. Electrodialytic Remediation of Soil Slurry-Removal of Cu, Cr, and As

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Jensen, Pernille Erland; Hansen, Henrik K.

    2009-01-01

    Severe soil contamination is often found at old wood preservation sites and a common combination of pollutants is Cu, Cr, and As. In the present work it is tested if simultaneous removal of Cu, Cr, and As can be obtained in an electrodialytic cell where the polluted soil is remediated as a stirred...... experiments; an experiment where the soil was suspended in distilled water and the remediation lasted 3 weeks with 2.5 mA and an experiment with acidification of the soil suspension with HNO3 to pH about 1.0 (2 weeks and 5 mA). The best separation of pollutants and soil was obtained in the experiment...... with suspension in distilled water. Based on soil concentrations, good Cu removal (95%) was obtained in both experiments. Removal of Cr was most efficient from the acidified soil suspension (74%). Both Cu and Cr concentrations were below the limiting values after the remediation. The As concentration, however...

  18. Electroless deposition of NiCrB diffusion barrier layer film for ULSI-Cu metallization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuechun [School of Materials Science and Engineering, Yunnan University, Kunming (China); Chen, Xiuhua, E-mail: chenxh@ynu.edu.cn [School of Materials Science and Engineering, Yunnan University, Kunming (China); Ma, Wenhui [National Engineering Laboratory of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming (China); Shang, Yudong; Lei, Zhengtao; Xiang, Fuwei [School of Materials Science and Engineering, Yunnan University, Kunming (China)

    2017-02-28

    Highlights: • In this paper, the electroless deposited NiCrB thin film was mainly in the form of NiB, CrB{sub 2} compounds and elementary Ni. • The sheet resistance of NiCrB thin film was 3.043 Ω/□, it is smaller than that of the widely used Ta, TaN and TiN diffusion barrier layers. • Annealing experiments showed that the failure temperature of NiCrB thin film regarding Cu diffusion was 900 °C. • NiCrB barrier layer crystallized after 900 °C annealing, Cu grains arrived at Si-substrate through grain boundaries, resulting in the formation of Cu{sub 3}Si. • Eelectroless deposited NiCrB film also had good oxidation resistance, it is expected to become an anti-oxidant layer of copper interconnection. - Abstract: NiCrB films were deposited on Si substrates using electroless deposition as a diffusion barrier layer for Cu interconnections. Samples of the prepared NiCrB/SiO{sub 2}/Si and NiCrB/Cu/NiCrB/SiO{sub 2}/Si were annealed at temperatures ranging from 500 °C to 900 °C. The reaction mechanism of the electroless deposition of the NiCrB film, the failure temperature and the failure mechanism of the NiCrB diffusion barrier layer were investigated. The prepared samples were subjected to XRD, XPS, FPP and AFM to determine the phases, composition, sheet resistance and surface morphology of samples before and after annealing. The results of these analyses indicated that the failure temperature of the NiCrB barrier film was 900 °C and the failure mechanism led to crystallization and grain growth of the NiCrB barrier layer after high temperature annealing. It was found that this process caused Cu grains to reach Si substrate through the grain boundaries, and then the reaction between Cu and Si resulted in the formation of highly resistive Cu{sub 3}Si.

  19. Activity of Aniline Methylation over Fe-Cu-Cr Ternary Spinel Systems

    Directory of Open Access Journals (Sweden)

    Reni George

    2014-03-01

    Full Text Available A series of spinels having thegeneral formula CuCr2-xFexO4 with x=0.25,0.75, 1.25, 1.75 were prepared by co-precipitation method. The catalysts werecharacterized by various physico-chemical methods like XRD, BET, UV-DRS, SEM,EDX, TPD etc. The reaction of aniline with methanol was studied in a fixed-bedreactor system as a potential source for the production of various methylanilines. It was observed that systems possessing low ‘x’ values are highlyselective and active for N-monoalkylation of aniline leading toN-methylaniline. Reaction parameters were properly varied to optimize thereaction conditions for obtaining N-methylaniline selectively and in betteryield. Among the systems CuCr1.75Fe0.25O4 isremarkable due to its very high activity and excellent stability. Under theoptimized conditions N-methylaniline selectivity exceeded 91%. CuCr1.25Fe0.75O4gives better conversion than CuCr1.75Fe0.25O4in CuCr2-xFexO4 series. The Lewis acid sitesof the catalysts are mainly responsible for the good catalytic performance. © 2014 BCREC UNDIP. All rights reservedSubmitted: 18th July 2013; Revised: 5th November 2013; Accepted: 1st December 2013[How to Cite: George, R., George, K., Sugunan, S. (2014. Activity of Aniline Methylation over Fe-Cu-Cr Ternary Spinel Systems. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (1: 39-44. (doi:10.9767/bcrec.9.1.5169.39-44][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.1.5169.39-44] 

  20. Characterization of CuCrZr and CuCrZr/SS junction strength for different blanket components manufacturing conditions

    International Nuclear Information System (INIS)

    Gillia, O.; Briottet, L.; Chu, I.; Lemoine, P.; Bucci, P.; Peacock, A.

    2007-01-01

    Full text of publication follows: This work describes studies on the strength of CuCrZr/SS joint for different manufacturing conditions foreseen for the fabrication of blanket components. In the meantime, as junction strength is expected to be strongly related to CuCrZr property, investigation on the properties of the CuCrZr itself after the different manufacturing conditions is also presented. The initial manufacturing conditions retained were made of a HIP treatment combined with a fast cooling plus a subsequent ageing treatment. For security reasons, the HIP quenching operation was not possible. It is too severe for the HIP vessel. A supplementary solutioning cycle has then been inserted to the heat treatment process just after the HIP-bonding treatment in order to have a sufficient fast cooling of the CuCrZr. The manufacturing conditions thus comprise a HIP cycle (simulated for mono-material samples), a separate solutioning cycle with controlled cooling rate and an ageing treatment. The influence of solutioning temperature has been addressed (1040 deg. C or 980 deg. C) as well as that of the cooling rate after solutioning (70 deg. C/min to water quench), the ageing temperature (480 deg. C or 560 deg. C) and the HIP temperature (1040 deg. C or 980 deg. C). Test results show that the ageing temperature is very important for keeping high strength of material whereas elongation properties are not very sensible to the manufacturing conditions. 1040 deg. C HIP or solutioning temperature gives better strength properties, as well as a higher cooling rate after solutioning. Concerning samples with junctions, it appears that CT test is more selective than other tests since tensile test does not give rupture at joint and KCU test eliminates a route without classifying other routes. A minimum value of J Q for CT test is given, but as confined plasticity requirement is not satisfied for the sample geometry, this value should only be used concomitantly with the same testing

  1. Low-field spin dynamics of Cr7Ni and Cr7Ni-Cu-Cr7Ni molecular rings as detected by μsR

    OpenAIRE

    Sanna, S.; Arosio, P.; Bordonali, L.; Adelnia, F.; Mariani, M.; Garlatti, E.; Baines, C.; Amato, A.; Sabareesh, K. P.V.; Timco, G.; Winpenny, R. E.P.; Blundell, S. J.; Lascialfari, A.

    2017-01-01

    Muon spin rotation measurements were used to investigate the spin dynamics of heterometallic Cr7Ni and Cr7Ni-Cu-Cr7Ni molecular clusters. In Cr7Ni the magnetic ions are arranged in a quasiplanar ring and interact via an antiferromagnetic exchange coupling constant J, while Cr7Ni-Cu-Cr7Ni is composed of two Cr7Ni linked by a bridging moiety containing one Cu ion, that induces an inter-ring ferromagnetic interaction J ≪ J. The longitudinal muon relaxation rate λ collected at low magnetic fields...

  2. Reclamation of Cr-contaminated or Cu-contaminated agricultural soils using sunflower and chelants.

    Science.gov (United States)

    Cicatelli, Angela; Guarino, Francesco; Castiglione, Stefano

    2017-04-01

    Chromium (Cr) and copper (Cu) are pollutants with a strong environmental impact. "Green biotechnology" as phytoremediation represents a sustainability opportunity for soil reclamation. In this study, we evaluated the possibility to reclaim agricultural soils located in the Solofrana valley, contaminated by Cr or Cu. Chromium contamination derives by repeated flooding events of Solofrana rivers containing Cr because of leather tanning plants, while Cu soil pollution was due to the use of Cu-rich pesticides in agriculture. Both metals showed a very low bioavailability. In order to perform an assisted phytoremediation of polluted fields, we carried out a preliminary ex situ experimentation testing for the first time sunflowers (cv. Pretor) and chelants (ethylenediaminetetraacetic acid (EDTA) and/or ethylene diamine disuccinate (EDDS)), useful when metal bioavailability is low. No symptoms of toxicity were observed in sunflowers grown on both soils, while biomass was improved when EDDS was added. Cr and Cu bioavailability was only slightly enhanced by chelants at the end of the treatments. Both Cr and Cu were mainly accumulated in the roots; moreover, Cu was also translocated to the aboveground organs in the presence of EDTA. The ex situ experimentation demonstrated that assisted phytoremediation is a very slow process not useful in the case of persistent pollution.

  3. Grain Refinement and Mechanical Properties of Cu-Cr-Zr Alloys with Different Nano-Sized TiCp Addition.

    Science.gov (United States)

    Zhang, Dongdong; Bai, Fang; Wang, Yong; Wang, Jinguo; Wang, Wenquan

    2017-08-08

    The TiC p /Cu master alloy was prepared via thermal explosion reaction. Afterwards, the nano-sized TiC p /Cu master alloy was dispersed by electromagnetic stirring casting into the melting Cu-Cr-Zr alloys to fabricate the nano-sized TiC p -reinforced Cu-Cr-Zr composites. Results show that nano-sized TiC p can effectively refine the grain size of Cu-Cr-Zr alloys. The morphologies of grain in Cu-Cr-Zr composites changed from dendritic grain to equiaxed crystal because of the addition and dispersion of nano-sized TiC p . The grain size decreased from 82 to 28 μm with the nano-sized TiC p content. Compared with Cu-Cr-Zr alloys, the ultimate compressive strength (σ UCS ) and yield strength (σ 0.2 ) of 4 wt% TiC p -reinforced Cu-Cr-Zr composites increased by 6.7% and 9.4%, respectively. The wear resistance of the nano-sized TiCp-reinforced Cu-Cr-Zr composites increased with the increasing nano-sized TiCp content. The wear loss of the nano-sized TiC p -reinforced Cu-Cr-Zr composites decreased with the increasing TiC p content under abrasive particles. The eletrical conductivity of Cu-Cr-Zr alloys, 2% and 4% nano-sized TiCp-reinforced Cu-Cr-Zr composites are 64.71% IACS, 56.77% IACS and 52.93% IACS, respectively.

  4. Characterization of CuCrZr and CuCrZr/SS joint strength for different blanket components manufacturing conditions

    Science.gov (United States)

    Gillia, Olivier; Briottet, Laurent; Chu, Isabelle; Lemoine, Patrick; Rigal, Emmanuel; Peacock, Alan

    2009-04-01

    This work describes studies on the strength of CuCrZr/SS joints for different manufacturing conditions foreseen for the fabrication of blanket components. In the meantime, as junction strength is expected to be strongly related to CuCrZr properties, investigation on the properties of the CuCrZr itself after the different manufacturing conditions is also presented. The initial manufacturing conditions retained were made of a HIP treatment combined with a fast cooling plus a subsequent ageing treatment. For security reasons, the HIP-quenching operation was not possible. A supplementary solutionning cycle with fast cooling has thus been inserted in the heat treatment process just after the HIP bonding treatment. The influence of solutionning temperature (1040 °C or 980 °C), the cooling rate after solutionning (70 °C/min to water quench), the ageing temperature (480 °C or 560 °C) and the HIP temperature (1040 °C or 980 °C) have been addressed. Test results show that the ageing temperature is very important for keeping high strength of material whereas elongation properties are not very sensible to the manufacturing conditions. 1040 °C HIP or solutionning temperature gives better strength properties, as well as a higher cooling rate after solutionning. Concerning samples with joints, it appears that CT test is more selective than other tests since tensile test does not give rupture at joint and KCU test eliminates a route without classifying other routes.

  5. Characterization of CuCrZr and CuCrZr/SS joint strength for different blanket components manufacturing conditions

    International Nuclear Information System (INIS)

    Gillia, Olivier; Briottet, Laurent; Chu, Isabelle; Lemoine, Patrick; Rigal, Emmanuel; Peacock, Alan

    2009-01-01

    This work describes studies on the strength of CuCrZr/SS joints for different manufacturing conditions foreseen for the fabrication of blanket components. In the meantime, as junction strength is expected to be strongly related to CuCrZr properties, investigation on the properties of the CuCrZr itself after the different manufacturing conditions is also presented. The initial manufacturing conditions retained were made of a HIP treatment combined with a fast cooling plus a subsequent ageing treatment. For security reasons, the HIP-quenching operation was not possible. A supplementary solutionning cycle with fast cooling has thus been inserted in the heat treatment process just after the HIP bonding treatment. The influence of solutionning temperature (1040 deg. C or 980 deg. C), the cooling rate after solutionning (70 deg. C/min to water quench), the ageing temperature (480 deg. C or 560 deg. C) and the HIP temperature (1040 deg. C or 980 deg. C) have been addressed. Test results show that the ageing temperature is very important for keeping high strength of material whereas elongation properties are not very sensible to the manufacturing conditions. 1040 deg. C HIP or solutionning temperature gives better strength properties, as well as a higher cooling rate after solutionning. Concerning samples with joints, it appears that CT test is more selective than other tests since tensile test does not give rupture at joint and KCU test eliminates a route without classifying other routes.

  6. The CdS/CdSe/ZnS Photoanode Cosensitized Solar Cells Basedon Pt, CuS, Cu2S, and PbS Counter Electrodes

    Directory of Open Access Journals (Sweden)

    Tung Ha Thanh

    2014-01-01

    Full Text Available Highly ordered mesoporous TiO2 modified by CdS, CdSe, and ZnS quantum dots (QDs was fabricated by successive ionic layer adsorption and reaction (SILAR method. The quantity of material deposition seems to be affected not only by the employed deposition method but also and mainly by the nature of the underlying layer. The CdS, CdSe, and ZnS QDs modification expands the photoresponse range of mesoporous TiO2 from ultraviolet region to visible range, as confirmed by UV-Vis spectrum. Optimized anode electrodes led to solar cells producing high current densities. Pt, CuS, PbS, and Cu2S have been used as electrocatalysts on counter electrodes. The maximum solar conversion efficiency reached in this work was 1.52% and was obtained by using Pt electrocatalyst. CuS, PbS, and Cu2S gave high currents and this was in line with the low charge transfer resistances recorded in their case.

  7. Effect of Cu-Cr co-substitution on magnetic properties of nanocrystalline magnesium ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Javed, E-mail: mjiqauchem@yahoo.com [Surface and Solid State Chemistry Laboratory, Department of Chemistry, Quaid-I-Azam University, Islamabad 45320 (Pakistan); Ahmad, Zahoor [Surface and Solid State Chemistry Laboratory, Department of Chemistry, Quaid-I-Azam University, Islamabad 45320 (Pakistan); Melikhov, Yevgen [Wolfson Centre for Magnetics, School of Engineering, Cardiff University, Cardiff CF24 3AA (United Kingdom); Nlebedim, Ikenna Cajetan [Ames Laboratory of US Department of Energy, Ames, IA 50011 (United States)

    2012-03-15

    This study deals with the temperature and composition dependence of magnetization and magnetic anisotropy of Cu{sup 2+}-Cr{sup 3+} co-substituted magnesium ferrite, Mg{sub 1-x}Cu{sub x}Cr{sub x}Fe{sub 2-x}O{sub 4} (x=0.0-0.5). The synthesized materials are characterized using thermo gravimetric analysis, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray fluorescence, Moessbauer spectrometer, superconducting quantum interference device magnetometer and vibrating sample magnetometer. The M-H loops measured up to 50 kOe at 300, 200 and 100 K, revealed narrow hysteresis curves with a coercive field and saturation magnetization varying for different compositions. The high field regimes of these loops are modeled using the Law of Approach to saturation to extract anisotropy information and saturation magnetization. Both the saturation magnetization and the anisotropy constant are observed to increase with the decrease in temperature while decrease with the Cu-Cr co-substituents for all the samples. Explanation of the observed behavior is proposed in terms of the preference of the co-substituent ions of Cu{sup 2+} and Cr{sup 3+} and their predominant choice to substitute into the octahedral sites of the cubic spinel lattice. - Highlights: Black-Right-Pointing-Pointer Mg{sub 1-x}Cu{sub x}Cr{sub x}Fe{sub 2-x}O{sub 4} was synthesized by novel PEG assisted microemulsion method. Black-Right-Pointing-Pointer Present paper dealt with magnetic properties of Mg{sub 1-x}Cu{sub x}Cr{sub x}Fe{sub 2-x}O{sub 4}. Black-Right-Pointing-Pointer XRD patterns revealed tetragonal distorted cubic structure of Mg{sub 1-x}Cu{sub x}Cr{sub x}Fe{sub 2-x}O{sub 4}. Black-Right-Pointing-Pointer Mossbauer spectroscopy confirmed that Cu-Cr occupy octahedral sites. Black-Right-Pointing-Pointer High field regime of M-H loops was modeled using Law of Approach to saturation.

  8. Synthesis, structure and magnetic properties of crystallographically aligned CuCr_2Se_4 thin films

    International Nuclear Information System (INIS)

    Esters, Marco; Liebig, Andreas; Ditto, Jeffrey J.; Falmbigl, Matthias; Albrecht, Manfred; Johnson, David C.

    2016-01-01

    We report the low temperature synthesis of highly textured CuCr_2Se_4 thin films using the modulated elemental reactant (MER) method. The structure of CuCr_2Se_4 is determined for the first time in its thin film form and exhibits cell parameters that are smaller than found in bulk CuCr_2Se_4. X-ray diffraction and precession electron diffraction show a strong degree of crystallographic alignment of the crystallites, where the axis is oriented perpendicular to the substrate surface, while being rotationally disordered within the plane. Temperature and field dependent in-plane and out-of-plane magnetization measurements show that the film is ferromagnetic with a Curie temperature of 406 K CuCr_2Se_4 synthesized utilizing the MER method shows stronger magnetic anisotropy (effective anisotropy: 1.82 × 10"6 erg cm"−"3; shape anisotropy: 1.07 × 10"6 erg cm"−"3), with the easy axis lying out of plane, and a larger magnetic moment (6 μ_B/f.u.) than bulk CuCr_2Se_4. - Highlights: • Crystallographically aligned, phase pure CuCr_2Se_4 were synthesized. • The degree of alignment decreases with annealing time. • The films are ferromagnetic with the easy axis along the direction. • The magnetization is larger than bulk CuCr_2Se_4 or other CuCr_2Se_4 films made to date.

  9. Interfacial electronic charge transfer and density of states in short period Cu/Cr multilayers; TOPICAL

    International Nuclear Information System (INIS)

    Barbee, T W; Bello, A F; Klepeis, J E; Van Buuren, T

    1999-01-01

    Nanometer period metallic multilayers are ideal structures to investigate electronic phenomena at interfaces between metal films since interfacial atoms comprise a large atomic fraction of the samples. The Cu/Cr binary pair is especially suited to study the interfaces in metals since these elements are mutually insoluble, thus eliminating mixing effects and compound formation and the lattice mismatch is very small. This allows the fabrication of high structural quality Cu/Cr multilayers that have a structure which can be approximated in calculations based on idealized atomic arrangements. The electronic structure of the Cu and the Cr layers in several samples of thin Cu/Cr multilayers were studied using x-ray absorption spectroscopy (XAS). Total electron yield was measured and used to study the white lines at the Cu L(sub 2) and L(sub 3) absorption edges. The white lines at the Cu absorption edges are strongly related to the unoccupied d-orbitals and are used to calculate the amount of charge transfer between the Cr and Cu atoms in interfaces. Analysis of the Cu white lines show a charge transfer of 0.026 electrons/interfacial Cu atom to the interfacial Cr atoms. In the Cu XAS spectra we also observe a van Hove singularity between the L(sub 2) and L(sub 3) absorption edges as expected from the structural analysis. The absorption spectra are compared to partial density of states obtained from a full-potential linear muffin-tin orbital calculation. The calculations support the presence of charge transfer and indicate that it is localized to the first two interfacial layers in both Cu and Cr

  10. Co-contamination of Cu and Cd in paddy fields: Using periphyton to entrap heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jiali [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Sciences, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China); College of Resource and Environment, University of Chinese Academy of Sciences, Beijing 100049 (China); Tang, Cilai [Department of Environmental Engineering, College of Hydraulic & Environmental Engineering, China Three Gorges University, Yichang 443002 (China); Wang, Fengwu [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Sciences, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China); School of Civil Engineering, East China Jiaotong University, 808 Shuang Gang East Road, Nanchang, Jiangxi 330013 (China); Wu, Yonghong, E-mail: yhwu@issas.ac.cn [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Sciences, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China)

    2016-03-05

    Highlights: • Periphyton was capable of simultaneously entrapping Cu and Cd from paddy fields. • Cu and Cd bioavailability decreased with time after exposure to periphyton. • Periodic adsorption–desorption was the main mechanism used to remove Cd and Cu. • Periphyton was able to adapt to steady accumulation of Cu and Cd. • The inclusion of periphyton will help entrap heavy metals in paddy fields. - Abstract: The ubiquitous native periphyton was used to entrap Cu and Cd from paddy fields. Results showed that Cu- and Cd-hydrate species such as CuOH{sup +}, Cu{sub 2}(OH){sub 2}{sup 2+}, CdOH{sup +}, and Cu{sub 3}(OH){sub 4}{sup 2+} decreased with time in the presence of periphyton. When the initial concentrations of Cu and Cd were 10 mg/L, the heavy metal content in the periphyton fluctuated from 145.20 mg/kg to 342.42 mg/kg for Cu and from 101.75 mg/kg to 236.29 mg/kg for Cd after 2 h exposure. The concentration of Cd in periphytic cells varied from 42.93 mg/kg to 174 mg/kg after 2 h. The dominant periphyton microorganism species shifted from photoautotrophs to heterotrophs during the exposure of periphyton to Cu and Cd co-contamination. Although Cu and Cd could inhibit periphyton photosynthesis and carbon utilization, the periphyton was able to adapt to the test conditions. Cu and Cd accumulation in rice markedly decreased in the presence of periphyton while the number of rice seeds germinating was higher in the periphyton treatments. These results suggest that the inclusion of native periphyton in paddy fields provides a promising buffer to minimize the effects of Cu and Cd pollution on rice growth and food safety.

  11. Relationship between Microstructure and Properties of Cu-Cr-Ag-(Ce) Alloy Using Microscopic Investigation.

    Science.gov (United States)

    Chen, Huiming; Yuan, Dawei; Wu, Shanjiang; Wang, Hang; Xie, Weibin; Yang, Bin

    2017-01-01

    Microstructure, precipitation hardening response, and mechanical and physical properties of Cu-Cr-Ag alloy and Cu-Cr-Ag-Ce alloy have been investigated using transmission electron microscopy, scanning electron microscope, optical microscope, electrical conductivity analysis, and tensile test. The influence of element Ce on the matrix refinement, impurity removal, and precipitation in the Cu-Cr-Ag alloys has been analyzed. The experimental results show that the strength and electrical conductivity of Ce containing alloys are greater than those of Ce-free alloys after each processing step. Improvement of strength and electrical conductivity of the Cu-Cr-Ag alloy by adding Ce element is attributed to removing oxygen and sulfur from as-cast alloy.

  12. Processing of Cu-Cr alloy for combined high strength and high conductivity

    Directory of Open Access Journals (Sweden)

    A.O Olofinjanaa

    2017-11-01

    Full Text Available High strength and high conductivity (HSHC are two intrinsic properties difficult to combine in metallic alloy design because; almost all strengthening mechanisms also lead to reduced conductivity. Precipitation hardening by nano-sized precipitates had proven to be the most adequate way to achieve the optimum combination of strength and conductivity in copper based alloys. However, established precipitation strengthened Cu- alloys are limited to very dilute concentration of solutes thereby limiting the volume proportion hardening precipitates. In this work, we report the investigation of the reprocessing of higher Cr concentration Cu- based alloys via rapid solidification. It is found that the rapid solidification in the as-cast ribbon imposed combined solution extension and ultra-refinement of Cr rich phases. X-ray diffraction evidences suggest that the solid solution extension was up to 6wt%Cr. Lattice parameters determined confirmed the many folds extension of solid solution of Cr in Cu.  Thermal aging studies of the cast ribbons indicated that peak aging treatments occurred in about twenty minutes. Peak aged hardness ranged from about 200 to well over 300Hv. The maximum peak aged hardness of 380Hv was obtained for alloy containing 6wt.%Cr but with conductivity of about 50%IACS. The best combined strength/conductivity was obtained for 4wt.%Cr  alloy with hardness of 350HV and conductivity of 80% IACS. The high strengths observed are attributed to the increased volume proportion of semi-coherent Cr rich nano-sized precipitates that evolved from the supersaturated solid solution of Cu-Cr that was achieved from the high cooling rates imposed by the ribbon casting process. The rapid overaging of the high Cr concentration Cu-Cr alloy is still a cause for concern in optimising the process for reaching peak HSHC properties. It is still important to investigate a microstructural design to slow or severely restrict the overaging process. The optimum

  13. Availability of heavy metals (Cd, Pb, And Cr) in agriculture from commercial fertilizers.

    Science.gov (United States)

    Nacke, H; Gonçalves, A C; Schwantes, D; Nava, I A; Strey, L; Coelho, G F

    2013-05-01

    The purpose of this study was to investigate the availability of the heavy metals cadmium (Cd), lead (Pb), and chromium (Cr) to soil and maize plants fertilized with different sources and doses of zinc (Zn) in a Rhodic Eutrudox soil. For that purpose, concentrations of Cd, Pb, and Cr were evaluated in leaf tissue and grains of maize plants and in 0-20 and 20-40 cm soil layers after fertilization with four doses of Zn from eight different sources of fertilizer. There was no accumulation of Cd, Pb, and Cr in maize grain and Cd and Cr in leaf tissue of the plants; nevertheless, there was accumulation of Pb in leaf tissue, showing its availability throughout different sources of Zn and consequent uptake by plants. Regarding the soil, it was observed that fertilizer from the different sources made Cd, Pb, and Cr available at increasing amounts proportional to increased Zn doses. Under experimental conditions, fertilization with Zn increased concentrations of heavy metals Cd, Pb and Cr in soil, further highlighting the importance of conducting more studies related to the application of mineral fertilizers for micronutrient supply and the availability of heavy metals.

  14. 3D-atom probe analysis of Cr and Cu added nitriding steels

    International Nuclear Information System (INIS)

    Takahashi, J.; Kawakami, K.; Sugiyama, M.; Kawasaki, K.

    2004-01-01

    Full text: Nitriding treatment is a very effective method for hardening the surface of steels and realizing improvement in wear-resistance. Although this technology has been performed for many years, the precipitation and hardening mechanisms are not completely clear. It was not easy to observe very fine precipitates which may be generated in nitriding steels. We performed a three-dimensional atom probe analysis of the nitriding steel plate in which two kinds of precipitates were generated. Hot-rolled steel plates, which mainly contained Cr 1.0wt.% and Cu 1.3wt.%, were nitrided by annealing (550-6000 o ) in a mainly NH 3 atmosphere. The material before the nitriding had a hardness of about 100 Hv. By the nitriding, the surface hardness increased to more than 700 Hv, and the inside hardness also increased to 200 Hv. The specimens were taken from 0.15 mm, 0.3 mm and 0.8 mm depth from the surface, which mostly correspond to the peak, the half and the inside hardness, respectively. In the specimen of 0.8 mm depth, prolate spheroidal Cu precipitates of more than 8 nm in diameter were observed. In the specimen of 0.3 mm depth, plate-shape nitride precipitates of 6-10 nm in diameter were observed in addition to the Cu precipitates. Each Cu precipitate made a pair with the nitride precipitate. In the 0.15 mm depth specimen, Cr nitride precipitates of high volume density in addition to the pairs consisting of a Cu precipitate and a Cr nitride precipitate were observed. The size of the nitride precipitate forming the pair was slightly larger than that of the single Cr nitride precipitates. Furthermore, the denuded zone where the nitride precipitate does not exist was observed around the pairs. From these results, it was concluded that three stages of precipitation arose as follows: By the heat treatment of nitriding processing, Cu precipitates were generated first. Then, Cr nitride nucleated at the surface of the Cu precipitates inhomogeneously, and surrounding solute Cr was

  15. Evaluation of the air quality regarding total suspended particles and heavy metals (Pb, Cd, Ni, Cu, Cr) in the Hermosillo city, Sonora, Mexico, during a yearly period; Evaluacion de la calidad del aire respecto de particulas suspendidas totales y metales pesados (Pb, Cd, Ni, Cu, Cr) en la Ciudad de Hermosillo, Sonora, Mexico, durante un periodo anual

    Energy Technology Data Exchange (ETDEWEB)

    Cruz C, M. E.; Quintero N, M. [Universidad Autonoma de Baja California, Instituto de Ingenieria, Campus Mexicali, Calle de la Normal s/n, y Blvd. Benito Juarez, Col. Insurgentes Este, Mexicali, Baja California (Mexico); Gomez A, A.; Varela S, J., E-mail: martincruzcampas@hotmail.com [Universidad de Sonora, Departamento de Ingenieria Quimica y Metalurgia, Blvd. Rosales y Luis Ensina s/n, Edificio 5B, Col. Centro, 83000 Hermosillo, Sonora (Mexico)

    2013-07-01

    In the present study, the air quality of the city of Hermosillo, Sonora, Mexico was assessed considering total suspended particulates (tsp) and heavy metals (Pb, Cd, Ni, Cu, Cr) from June 2001 through May 2002 in three monitoring sites Centro (Mazon), Nor este (CESUES) and Noroeste (CBTIS). The filter-samples used for that purpose were provided by the Air Quality Evaluation and Improvement Program (PEMCA) of the municipality of Hermosillo. The sampling method was based on high volume sampling frequency set every 6 days with non-simultaneous sampling among the three sampling sites. Filters were dissolved for metal determination by acidic-extraction, and then analyzed by flame atomic absorption spectrophotometry. Results indicate that tsp concentrations at Centro and Noroeste sites were frequently higher than the maximum daily permissible level (260 {mu}g/m{sup 3}), while in the three sites the annual average was higher than the maximum annual permissible level (75 {mu}g/m{sup 3}) both established in the standard NOM-024-Ssa-1993 (Ssa 1994a). According to the Air Quality Standard Index (US EPA 1992a), used in Mexico by Air Quality Metropolitan Index (IMECA) the results indicate that the air quality in the city of Hermosillo regarding tsp was placed between no satisfactory and poor. In regard to heavy metals (Pb, Cd, Ni, Cu, Cr), concentrations detected were below the maximum permissible levels and/or criteria taking into account the standard NOM-026-Ssa-1993 (Ssa 1994b), the Who criterion (2000), the European Union criterion (Cec 2003), and the European Environmental Agency criteria (EEA 2004). Such findings would mean that airborne metals are of no concern; however, air quality is still classified as no satisfactory due to high particulate matter concentrations. Keeping air quality parameters monitoring is recommended in order to get extensive data for use in risk studies of air quality and health (morbidity/mortality), as well as topographic conditions

  16. Research on aging precipitation in a Cu-Cr-Zr-Mg alloy

    International Nuclear Information System (INIS)

    Su Juanhua; Dong Qiming; Liu Ping; Li Hejun; Kang Buxi

    2005-01-01

    The effects of aging processes on the properties and microstructure of Cu-0.3Cr-0.15Zr-0.05Mg lead frame alloy were investigated. Aging precipitation phase was dealt with by transmission electronic microscope (TEM). After solid solution was treated at 920 deg. C and aged at 470 deg. C for 4 h, the fine precipitation of an ordered compound CrCu 2 (Zr, Mg) is found in copper matrix as well as fine Cr and Cu 4 Zr. Along the grain boundary, there are larger chromium. The hardness and electrical conductivity can reach 109 HV and 80% IACS, respectively. Sixty percent cold-rolled deformation prior to aging at 470 deg. C enhances the hardness of the alloy. The coherent precipitates Cr in copper matrix and the dislocations pinned by the fine precipitates are responsible for maximum strengthening of the alloy. So the hardness 165 HV and electrical conductivity 79.2% IACS are available

  17. A novel coping metal material CoCrCu alloy fabricated by selective laser melting with antimicrobial and antibiofilm properties

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Ling [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Memarzadeh, Kaveh [Institute of Dentistry, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, Newark Street, London E1 2AT (United Kingdom); Zhang, Shuyuan; Sun, Ziqing; Yang, Chunguang [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Ren, Guogang [University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Allaker, Robert P., E-mail: r.p.allaker@qmul.ac.uk [Institute of Dentistry, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, Newark Street, London E1 2AT (United Kingdom); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

    2016-10-01

    Objective: The aim of this study was to fabricate a novel coping metal CoCrCu alloy using a selective laser melting (SLM) technique with antimicrobial and antibiofilm activities and to investigate its microstructure, mechanical properties, corrosion resistance and biocompatibility. Methods: Novel CoCrCu alloy was fabricated using SLM from a mixture of commercial CoCr based alloy and elemental Cu powders. SLM CoCr without Cu served as control. Antibacterial activity was analyzed using standard antimicrobial tests, and antibiofilm properties were investigated using confocal laser scanning microscope. Cu distribution and microstructure were determined using scanning electron microscope, optical microscopy and X-ray diffraction. Corrosion resistance was evaluated by potential dynamic polarization and biocompatibility measured using an MTT assay. Results: SLM CoCrCu alloys were found to be bactericidal and able to inhibit biofilm formation. Other factors such as microstructure, mechanical properties, corrosion resistance and biocompatibility were similar to those of SLM CoCr alloys. Significance: The addition of appropriate amounts of Cu not only maintains normal beneficial properties of CoCr based alloys, but also provides SLM CoCrCu alloys with excellent antibacterial and antibiofilm capabilities. This material has the potential to be used as a coping metal for dental applications. - Highlights: • Novel CoCrCu alloys were fabricated by using selective laser melting (SLM). • SLM CoCrCu alloys showed satisfied antimicrobial and antibiofilm activities. • SLM CoCrCu alloys have no cytotoxic effect on normal cells. • Other properties of SLM CoCrCu alloys were similar to SLM CoCr alloys. • SLM CoCrCu alloys have the potential to be used as coping metals.

  18. A novel coping metal material CoCrCu alloy fabricated by selective laser melting with antimicrobial and antibiofilm properties

    International Nuclear Information System (INIS)

    Ren, Ling; Memarzadeh, Kaveh; Zhang, Shuyuan; Sun, Ziqing; Yang, Chunguang; Ren, Guogang; Allaker, Robert P.; Yang, Ke

    2016-01-01

    Objective: The aim of this study was to fabricate a novel coping metal CoCrCu alloy using a selective laser melting (SLM) technique with antimicrobial and antibiofilm activities and to investigate its microstructure, mechanical properties, corrosion resistance and biocompatibility. Methods: Novel CoCrCu alloy was fabricated using SLM from a mixture of commercial CoCr based alloy and elemental Cu powders. SLM CoCr without Cu served as control. Antibacterial activity was analyzed using standard antimicrobial tests, and antibiofilm properties were investigated using confocal laser scanning microscope. Cu distribution and microstructure were determined using scanning electron microscope, optical microscopy and X-ray diffraction. Corrosion resistance was evaluated by potential dynamic polarization and biocompatibility measured using an MTT assay. Results: SLM CoCrCu alloys were found to be bactericidal and able to inhibit biofilm formation. Other factors such as microstructure, mechanical properties, corrosion resistance and biocompatibility were similar to those of SLM CoCr alloys. Significance: The addition of appropriate amounts of Cu not only maintains normal beneficial properties of CoCr based alloys, but also provides SLM CoCrCu alloys with excellent antibacterial and antibiofilm capabilities. This material has the potential to be used as a coping metal for dental applications. - Highlights: • Novel CoCrCu alloys were fabricated by using selective laser melting (SLM). • SLM CoCrCu alloys showed satisfied antimicrobial and antibiofilm activities. • SLM CoCrCu alloys have no cytotoxic effect on normal cells. • Other properties of SLM CoCrCu alloys were similar to SLM CoCr alloys. • SLM CoCrCu alloys have the potential to be used as coping metals.

  19. Electroluminescent Cu-doped CdS quantum dots

    NARCIS (Netherlands)

    Stouwdam, J.W.; Janssen, R.A.J.

    2009-01-01

    Incorporating Cu-doped CdS quantum dots into a polymer host produces efficient light-emitting diodes. The Cu dopant creates a trap level that aligns with the valence band of the host, enabling the direct injection of holes into the quantum dots, which act as emitters. At low current densities, the

  20. Half-metallic antiferromagnetism in double perovskite BiPbCrCuO6

    International Nuclear Information System (INIS)

    Weng, Ke-Chuan; Wang, Y. K.

    2015-01-01

    The electronic structure and magnetic properties of BiPbCrCuO 6 double perovskite are investigated based on first-principles density functional calculations with generalized gradient approximation (GGA) and GGA incorporated with Coulomb correlation interaction U (GGA + U). The results suggest the half-metallic (HM) and antiferromagnetic (AFM) properties of BiPbCrCuO 6 double perovskite. The HM-AFM property of the double perovskite is caused by the double-exchange mechanism between neighboring Cr 5+ (t 2g 1 ↓) and Cu 2+ (t 2g 3 ↑t 2g 3 ↓e g 2 ↑e g ↓) via the intermediate O 2− (2s 2 2p 6 ) ion

  1. Lattice parameter values and phase transitions for the Cu2Cd1-zMnzSnSe4 and Cu2Cd1-zFezSnSe4 alloys

    International Nuclear Information System (INIS)

    Moreno, E.; Quintero, M.; Morocoima, M.; Quintero, E.; Grima, P.; Tovar, R.; Bocaranda, P.; Delgado, G.E.; Contreras, J.E.; Mora, A.E.; Briceno, J.M.; Avila Godoy, R.; Fernandez, J.L.; Henao, J.A.; Macias, M.A.

    2009-01-01

    X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu 2 Cd 1-z Mn z SnSe 4 and Cu 2 Cd 1-z Fe z SnSe 4 alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. For Cu 2 Cd 0.8 Fe 0.2 SnSe 4 as well as for Cu 2 Cd 0.2 Fe 0.8 SnSe 4 the crystal structures were refined using the Rietveld method. It was found that the internal distortion parameter σ decreases as Cd is replaced by either Mn and/or Fe. For the Cu 2 Cd 1-z Mn z SnSe 4 and Cu 2 Cd 1-z Fe z SnSe 4 alloy systems, only two single solid phase fields, the tetragonal stannite α(I4-bar2m) and the wurtz-stannite δ (Pmn2 1 ) structures were found to occur in the diagram. In addition to the tetragonal stannite α phase extra X-ray diffraction lines due to MnSe and/or FeSe 2 were observed for as grown samples in the range 0.7 < z < 1.0. However, it was found that the amount of the extra phase decreased for the compressed samples.

  2. Newly developed EMF cell with zirconia solid electrolyte for measurement of low oxygen potentials in liquid Cu-Cr and Cu-Zr alloys

    Directory of Open Access Journals (Sweden)

    Katayama I.

    2012-01-01

    Full Text Available In order to measure the very low oxygen potential by use of stabilized zirconia solid electrolyte emf method, a new cell construction was devised. The idea was based on Janke but a zirconia rod was used instead of the zirconia crucible which contacts liquid alloy electrode. The cell was used for determination of the oxygen potentials in liquid dilute Cu-Cr and Cu-Zr alloys. The reference electrode was Cr,Cr2O3. Emf measurements were performed in the temperature range of 1400-1580K and composition range of 0.198-3.10at%Cr-Cu alloys, and 1380-1465K, 0.085-0.761at%Zr-Cu alloys. The composition of liquid alloys were determined by picking up from the liquid alloys and ICP analysis. By use of the newly devised cell construction in this study, stable emf values were obtained at each temperature and alloy composition. Emf values were corrected by using the parameter for electronic contribution of the YSZ. Activity of Cr obeys Henry’s law and activity coefficient at infinitely dilute alloys of Cr in Cu-Cr alloys are: lng0 Cr =(3.80 at 1423K, (3.57 at 1473K, (3.38 at 1523K and (3.20 at 1573K. At 1423 K activity coefficient of Zr at infinitely diluted alloy is lnγo Zr = -4.0.

  3. N–Mg dual-acceptor co-doping in CuCrO{sub 2} studied by first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ying, E-mail: 1080071@hnust.edu.cn [School of Physics, Hunan University of Science and Technology, Xiangtan 411201 (China); Nie, Guo-Zheng [School of Physics, Hunan University of Science and Technology, Xiangtan 411201 (China); Zou, Daifeng [School of Physics, Hunan University of Science and Technology, Xiangtan 411201 (China); Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Science, Shenzhen 518055 (China); Tang, Jing-Wu [School of Physics, Hunan University of Science and Technology, Xiangtan 411201 (China); Ao, Zhimin, E-mail: Zhimin.Ao@gdut.edu.cn [Institute of Environmental Health and Pollution Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006 (China)

    2016-11-25

    In this paper, N–Mg dual-acceptor co-doping in CuCrO{sub 2} is investigated by first-principles calculations. The electronic structure and formation energies of Mg substituting Cr-site, N substituting O-site, and co-doping of both Mg on Cr-site and N on O-site in CuCrO{sub 2} are calculated. It is found that the structure with N and Mg codoped at the nearest sites has the lowest energy due to a modest attractive interaction between the two dopants. Compared with single N or Mg doped CuCrO{sub 2}, the N–Mg codoped CuCrO{sub 2} has a lower formation energy and shallower transition level. In addition, the total density of states (DOS) analysis shows that more hole states appear above the Fermi level and higher DOS for N–Mg co-doping is obtained in the N–Mg codoped CuCrO{sub 2}, which is good to enhance the p-type conductivity in CuCrO{sub 2}. - Highlights: • N–Mg dual-acceptor co-doping in CuCrO{sub 2} is investigated. • N–Mg complex has a lower formation energy and shallower transition level. • More hole states appear above the Fermi level for N–Mg co-doping. • N–Mg co-doping in CuCrO{sub 2} can be expected to have more stable p-type conductivity.

  4. Order–disorder phenomena in layered CuCrSe2 crystals

    International Nuclear Information System (INIS)

    Gagor, A.; Gnida, D.; Pietraszko, A.

    2014-01-01

    The thermal motion of Cu + ions in a quasi-two dimensional copper ion conductor CuCrSe 2 is studied in the vicinity of the order-disorder phase transition to superionic phase, basing on a single-crystal and powder X-ray diffraction, specific heat and electrical resistivity measurements. The copper ions gradually migrate with temperature decrease to empty tetrahedral sites reaching occupancy equilibrium in the disordered high-temperature phase at T s  = 365 K. The copper migration between Cuα and Cuβ tetrahedral sites occurs through the neighboring, face-sharing octahedral holes. Disorder of Cu + ions brings perturbations in periodic potential of the crystal lattice providing additional scattering centers for electrons. - Graphical abstract: Copper migration within α and β sites. - Highlights: • Single crystals of CuCrSe 2 have been grown by vapor transport. • Thermally activated motion of Cu + ions is analyzed from T = 295 up to 420 K. • An order–disorder phase transition at T s  = 365 K leads to fast ion conducting state. • Interplay between lattice vibrations and Se polarizability accounts for Cu + hops. • Electrical resistivity near the T s shows two additional scattering centers

  5. Pollution of soils (Pb, Cd, Cr, Zn, Cu, Ni) along the ring road of Wrocław (Poland)

    Science.gov (United States)

    Hołtra, Anna; Zamorska-Wojdyła, Dorota

    2017-11-01

    The concentrations of metallic pollution in soils and plants along the ring road of Wrocław, Poland, have been determined. Environmental samples were collected from the surface layer of the profile within 2-3 m from the edge of the road. The analysis of metals (Pb, Cd, Cr, Zn, Cu and Ni) has been carried out through FAAS and GFAAS methods. The mineralizates of soils and plants were prepared in HNO3, 65% supra pure, using the Microwave Digestion System. The pH and conductivity of the soil solutions were measured to evaluate their active and exchangeable acidity and the salinity of the soils. The index of the enrichment of soils in metals (Wn) and the bioaccumulation coefficient (WB) have been determined. Also, histograms of the frequency of the occurrence of metals in the environmental samples and the Pearson's correlation coefficients were presented. The results of metal concentrations in soils were compared to the geochemical background in uncontaminated soils of Poland. The assessment of the results in the soils was also made relative to the standard, according to the Polish Ministry of Environment Regulation from September 1st, 2016. During the assessment of the bioaccumulation coefficients of metals in plants a reference was made to the content of undesirable substances in feed in agreement with the Polish Ministry of Agriculture and Rural Development Regulation from January 23rd, 2007.

  6. Cyclic Oxidation Behavior of CuCrAl Cold-Sprayed Coatings for Reusable Launch Vehicles

    Science.gov (United States)

    Raj, Sai; Karthikeyan, J.

    2009-01-01

    The next generation of reusable launch vehicles is likely to use GRCop-84 [Cu-8(at.%)Cr-4%Nb] copper alloy combustion liners. The application of protective coatings on GRCop-84 liners can minimize or eliminate many of the environmental problems experienced by uncoated liners and significantly extend their operational lives and lower operational cost. A newly developed Cu- 23 (wt.%) Cr-5% Al (CuCrAl) coating, shown to resist hydrogen attack and oxidation in an as-cast form, is currently being considered as a protective coating for GRCop-84. The coating was deposited on GRCop-84 substrates by the cold spray deposition technique, where the CuCrAl was procured as gas-atomized powders. Cyclic oxidation tests were conducted between 773 and 1,073 K to characterize the coated substrates.

  7. Effect of pH on corrosion behavior of CuCrZr in solution without and with NaCl

    Energy Technology Data Exchange (ETDEWEB)

    Kwok, C.T.; Wong, P.K. [Department of Electromechanical Engineering, University of Macau (China); Man, H.C. [Department of Industrial and Systems Engineering, Hong Kong Polytechnic University (Hong Kong); Cheng, F.T., E-mail: apaftche@polyu.edu.h [Department of Applied Physics, Hong Kong Polytechnic University (Hong Kong)

    2009-10-01

    CuCrZr is a high copper alloy widely used as electrical and thermal conducting material, especially in heat exchangers in nuclear reactors. In this respect, the physical and fatigue properties of CuCrZr have been extensively studied. The electrochemical behavior of CuCrZr, on the other hand, has not been adequately investigated. In the present study, the effect of pH on the corrosion behavior of CuCrZr in aqueous solutions without and with chloride (0.6 M NaCl) was studied. The pH of the solutions is found to exert significant influence on the corrosion behavior of CuCrZr. In acidic solutions without chloride, the corrosion of CuCrZr is ascribed to active dissolution with soluble products. In neutral and alkaline solutions without NaCl, the presence of oxides on the surface of CuCrZr leads to a noble shift in corrosion potential and passivation results in increased corrosion resistance. In chloride solutions at various pH values, the chloride ions influence the formation of the surface layers and the anodic dissolution process during polarization. At high pH, CuCrZr shows significant passivity and high corrosion resistance due to the growth of Cu{sub 2}O/Cu(OH) film which hinders further dissolution whereas at low pH the corrosion resistance is lowered due to active dissolution of Cu.

  8. Effect of pH on corrosion behavior of CuCrZr in solution without and with NaCl

    International Nuclear Information System (INIS)

    Kwok, C.T.; Wong, P.K.; Man, H.C.; Cheng, F.T.

    2009-01-01

    CuCrZr is a high copper alloy widely used as electrical and thermal conducting material, especially in heat exchangers in nuclear reactors. In this respect, the physical and fatigue properties of CuCrZr have been extensively studied. The electrochemical behavior of CuCrZr, on the other hand, has not been adequately investigated. In the present study, the effect of pH on the corrosion behavior of CuCrZr in aqueous solutions without and with chloride (0.6 M NaCl) was studied. The pH of the solutions is found to exert significant influence on the corrosion behavior of CuCrZr. In acidic solutions without chloride, the corrosion of CuCrZr is ascribed to active dissolution with soluble products. In neutral and alkaline solutions without NaCl, the presence of oxides on the surface of CuCrZr leads to a noble shift in corrosion potential and passivation results in increased corrosion resistance. In chloride solutions at various pH values, the chloride ions influence the formation of the surface layers and the anodic dissolution process during polarization. At high pH, CuCrZr shows significant passivity and high corrosion resistance due to the growth of Cu 2 O/Cu(OH) film which hinders further dissolution whereas at low pH the corrosion resistance is lowered due to active dissolution of Cu.

  9. Bioaccumulation of toxic metals (Cd and Cu) by Groenlandia densa (L.) Fourr.

    Science.gov (United States)

    Kara, Yesim; Zeytunluoglu, Ali

    2007-12-01

    In this study, Groenlandia densa (L.) Fourr. (opposite-leaved pondweed), was exposed to prepared stock solution of cadmium and copper with 1.0, 3.0, 5.0 and 7.0 mg L(-1) concentration in certain periods (24, 48, 72 and 96 h) and changing amount of accumulation of plants in depending on time and concentration was measured by atomic absorption spectrophotometer. The results show that under experimental conditions, G. densa (L.) Fourr. proved to be a good accumulator of Cd and Cu. Removal of the metals from solution was fast in the first 4 days. The accumulation of Cd and Cu increased with the initial concentration and also with time. The highest concentrations of each trace element accumulated in opposite-leaved pondweed tissues were 1,955 mug Cd g(-1), 6,135 microg Cu g(-1) after 4 days. The maximum values of bioconcentration factor (BCF) were found for Cd and Cu 724 and 1,669, respectively. BCF values for Cd and Cu increased with time.

  10. Study on Characteristics of CdS/Cu2S Photovoltaic Cell

    International Nuclear Information System (INIS)

    Nwe Nwe Htun

    2011-12-01

    In this paper the CdS-Cu2S photovoltaic cell has been prepared and characteristiced by using evaporation method on glass substrate. CdS film was deposited on the Pyrex glass substrate by evaporation and Cu2S layer was obtained by electroplating in a dilute acqueous solution of CusO4 at room temperature. Silver electrode was applied to the electroplated surface. The results of electrical and optical characteristics of the CdS-Cu2S hetrojunction were investigated. The photovoltaic response has been observed under various illuminated intensity for different wavelengths in visible region. It was found to be the photovoltage and photocurrent varying with different light intensities. It can be concluded that formation of a low resistivity CdS film and Cu2S layer play a big role in obtaining a high efficiency cell.

  11. Spatial distribution of Cd and Cu in soils in Shenyang Zhangshi Irrigation Area (SZIA), China*

    Science.gov (United States)

    Sun, Li-na; Yang, Xiao-bo; Wang, Wen-qing; Ma, Li; Chen, Su

    2008-01-01

    Heavy metal contamination of soils, derived from sewage irrigation, mining and inappropriate utilization of various agrochemicals and pesticides, and so on, has been of wide concern in the last several decades. The Shenyang Zhangshi Irrigation Area (SZIA) in China is a representative area of heavy metal contamination of soils resulting from sewage irrigation for about 30 years. This study investigated the spatial distribution and temporal variation of soil cadmium (Cd) and copper (Cu) contamination in the SZIA. The soil samples were collected from the SZIA in 1990 and 2004; Cd and Cu in soils was analyzed and then the spatial distribution and temporal variation of Cd and Cu in soils were modeled using Kriging methods. The results show that long-term sewage irrigation had caused serious Cd and Cu contamination in soils. The mean and the maximum of soil Cd are markedly higher than the levels in second grade standard soil (LSGSS) in China, and the maximum of soil Cu is close to the LSGSS in China in 2004 and is more than the LSGSS in China in 1990. The contamination magnitude of soil Cd and the soil extent of Cd contamination had evidently increased since sewage irrigation ceased in 1992. The contamination magnitude of soil Cu and the soil extent of Cu contamination had evidently increased in topsoil, but obviously decresed in subsoil. The soil contamination of Cd and Cu was mainly related to Cd and Cu reactivation of contaminated sediments in Shenyang Xi River and the import of Cd and Cu during irrigation. The eluviation of Cd and Cu in contaminated topsoil with rainfall and irrigation water was another factor of temporal-spatial variability of Cd and Cu contamination in soils. PMID:18357631

  12. Heavy doping of CdTe single crystals by Cr ion implantation

    Science.gov (United States)

    Popovych, Volodymyr D.; Böttger, Roman; Heller, Rene; Zhou, Shengqiang; Bester, Mariusz; Cieniek, Bogumil; Mroczka, Robert; Lopucki, Rafal; Sagan, Piotr; Kuzma, Marian

    2018-03-01

    Implantation of bulk CdTe single crystals with high fluences of 500 keV Cr+ ions was performed to achieve Cr concentration above the equilibrium solubility limit of this element in CdTe lattice. The structure and composition of the implanted samples were studied using secondary ion mass spectrometry (SIMS), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS) to characterize the incorporation of chromium into the host lattice and to investigate irradiation-induced damage build-up. It was found that out-diffusion of Cr atoms and sputtering of the targets alter the depth distribution and limit concentration of the projectile ions in the as-implanted samples. Appearance of crystallographically oriented, metallic α-Cr nanoparticles inside CdTe matrix was found after implantation, as well as a strong disorder at the depth far beyond the projected range of the implanted ions.

  13. Enhancement strategies for Cu(II), Cr(III) and Cr(VI) remediation by a variety of seaweed species.

    Science.gov (United States)

    Murphy, V; Hughes, H; McLoughlin, P

    2009-07-15

    Various chemical treatments have been applied to six brown, red and green seaweed species with a view to enhancing their metal removal for Cu(II), Cr(III) and Cr(VI). Treatment with acetone resulted in the greatest enhancement for both cationic and anionic species with relatively low mass losses (15-35%), indicating its low risk to biomass operational stability. Cation binding was increased by 69%, while the total Cr removal was augmented by 15%. Cr(VI) binding was shown to be an adsorption-coupled reduction, whereby Cr(VI) was bound to the biomass surface at pH 2 and subsequently reduced to Cr(III). Acetone treatment also resulted in biomasses that were capable of converting up to 83% of Cr(VI) in solution to Cr(III). Blocking of carboxyl and amino functionalities had significant negative effects both on total Cr removal as well as percentage conversion of Cr(VI) to Cr(III). Results therefore indicated the significant role played by these moieties in metal binding to these seaweeds. Potentiometric titrations displayed agreement between the degree of esterification and the decrease in Cu(II) removal for Ulva spp. and Polysiphonia lanosa. FTIR analysis identified changes in biomass functionality and availability after chemical modification, the results of which were in agreement with metal removal studies. In conclusion, these biosorbents represent suitable candidates to replace conventional removal technologies for metal bearing wastewaters, in particular for the detoxification of hazardous Cr(VI) waste streams.

  14. Evaluation of the air quality regarding total suspended particles and heavy metals (Pb, Cd, Ni, Cu, Cr) in the Hermosillo city, Sonora, Mexico, during a yearly period

    International Nuclear Information System (INIS)

    Cruz C, M. E.; Quintero N, M.; Gomez A, A.; Varela S, J.

    2013-01-01

    In the present study, the air quality of the city of Hermosillo, Sonora, Mexico was assessed considering total suspended particulates (tsp) and heavy metals (Pb, Cd, Ni, Cu, Cr) from June 2001 through May 2002 in three monitoring sites Centro (Mazon), Nor este (CESUES) and Noroeste (CBTIS). The filter-samples used for that purpose were provided by the Air Quality Evaluation and Improvement Program (PEMCA) of the municipality of Hermosillo. The sampling method was based on high volume sampling frequency set every 6 days with non-simultaneous sampling among the three sampling sites. Filters were dissolved for metal determination by acidic-extraction, and then analyzed by flame atomic absorption spectrophotometry. Results indicate that tsp concentrations at Centro and Noroeste sites were frequently higher than the maximum daily permissible level (260 μg/m 3 ), while in the three sites the annual average was higher than the maximum annual permissible level (75 μg/m 3 ) both established in the standard NOM-024-Ssa-1993 (Ssa 1994a). According to the Air Quality Standard Index (US EPA 1992a), used in Mexico by Air Quality Metropolitan Index (IMECA) the results indicate that the air quality in the city of Hermosillo regarding tsp was placed between no satisfactory and poor. In regard to heavy metals (Pb, Cd, Ni, Cu, Cr), concentrations detected were below the maximum permissible levels and/or criteria taking into account the standard NOM-026-Ssa-1993 (Ssa 1994b), the Who criterion (2000), the European Union criterion (Cec 2003), and the European Environmental Agency criteria (EEA 2004). Such findings would mean that airborne metals are of no concern; however, air quality is still classified as no satisfactory due to high particulate matter concentrations. Keeping air quality parameters monitoring is recommended in order to get extensive data for use in risk studies of air quality and health (morbidity/mortality), as well as topographic conditions, meteorological and

  15. VALIDACIÓN DE LA METODOLOGÍA PARA LA DETERMINACIÓN DE SB, AS, CD, CU, CR, HG, NI, PB Y ZN EN SEDIMENTOS POR ICO-MS

    Directory of Open Access Journals (Sweden)

    Hermógenes Rosas Rodríguez

    2004-01-01

    Full Text Available En este trabajo se presentan los resultados obtenidos en la validación de la técnica ICP-MS utilizada para la determinación de nueve elementos en sedimentos: Sb, As, Cd, Cu, Cr, Hg, Ni, Pb y Zn. Para ello se llevó a cabo el estudio de los siguientes parámetros de fiabilidad: precisión, exactitud y límites de detección y cuantificación. Para el análisis de estos elementos se utilizó un ICP-MS ELAN 6000 de Perkin Elmer®. El estudio de los distintos parámetros de validación fue muy satisfactorio para la mayoría de los analitos, alcanzándose límites de detección y de cuantificación muy bajos (inferiores a 1microg/l e incluso de 1 ng/l para el Cd. El método ICP-MS es exacto y preciso, obteniéndose para la mayoría de los elementos coeficientes de variación en torno al 2% y porcentajes de recuperación del 100%.

  16. Design and characterization of FeCrNiCoAlCu and FeCrNiCo(AlCu){sub 0,5} multicomponent alloys; Previsao e caracterizacao de ligas multicomponentes FeCrNiCoAlCu e FeCrNiCo(AlCu){sub 0,5}

    Energy Technology Data Exchange (ETDEWEB)

    Triveno Rios, Carlos; Artacho, Victor Falcao [Universidade Federal do ABC (CECS/UFABC), Santo Andre, SP (Brazil). Engenharia de Materiais

    2014-07-01

    High entropy alloys using multi-element main quasi-equivalent atomic proportions and generally forms single-phase solid solution and has the ability to enhance levels of strain hardening combined with high levels of plastic deformation at room temperature. In this work two high-entropy alloys with almost similar composition were studied and the factors influencing the formation of solid solution phases (δ atomic radius difference, ΔH{sub mix} mixing enthalpy, ΔS{sub mix} mixing entropy) were evaluated. The microstructure as-cast and the compositions of phases in the two alloys were analyzed by SEM and XRD. The mechanical characterization was realized by measurements of microhardness and cold compression test. The results showed that FeCrNiCo(AlCu){sub 0,5} and FeCrNiCoAlCu alloys with δ equal to 5,7 and 4,9, respectively, form alloys with solid solutions of high entropy. However, the presence of FC and BCCC structures greatly influence the mechanical properties. (author)

  17. Improvement of the crystallographic orientation of double-layered perpendicular recording media by using CoCr (Mo)/Cu intermediate layers

    International Nuclear Information System (INIS)

    Tamai, Ichiro; Yamamoto, T.; Kikukawa, A.; Tanahashi, K.; Ishikawa, A.; Futamoto, M.

    2001-01-01

    We have introduced intermediate layers of CoCr/Cu and CoCrMo/Cu between a CoCrPtB recording layer and a soft-magnetic CoTaZr underlayer. The combination of the FCC-Cu first-intermediate layer and the HCP-CoCrMo second-intermediate layer was found to enhance the c-axis vertical orientation of the CoCrPtB recording layer. In media with intermediate layers of CoCrMo/Cu, the thickness of the intermediate layers can be reduced without sacrificing good magnetic properties, and this leads to high resolutions

  18. Synthesis, structure and magnetic properties of crystallographically aligned CuCr{sub 2}Se{sub 4} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Esters, Marco [Department of Chemistry, University of Oregon, Eugene, OR 97403 (United States); Liebig, Andreas [Institut für Physik, Universität Augsburg, 86159 Augsburg (Germany); Ditto, Jeffrey J.; Falmbigl, Matthias [Department of Chemistry, University of Oregon, Eugene, OR 97403 (United States); Albrecht, Manfred [Institut für Physik, Universität Augsburg, 86159 Augsburg (Germany); Johnson, David C., E-mail: davej@uoregon.edu [Department of Chemistry, University of Oregon, Eugene, OR 97403 (United States)

    2016-06-25

    We report the low temperature synthesis of highly textured CuCr{sub 2}Se{sub 4} thin films using the modulated elemental reactant (MER) method. The structure of CuCr{sub 2}Se{sub 4} is determined for the first time in its thin film form and exhibits cell parameters that are smaller than found in bulk CuCr{sub 2}Se{sub 4}. X-ray diffraction and precession electron diffraction show a strong degree of crystallographic alignment of the crystallites, where the <111> axis is oriented perpendicular to the substrate surface, while being rotationally disordered within the plane. Temperature and field dependent in-plane and out-of-plane magnetization measurements show that the film is ferromagnetic with a Curie temperature of 406 K CuCr{sub 2}Se{sub 4} synthesized utilizing the MER method shows stronger magnetic anisotropy (effective anisotropy: 1.82 × 10{sup 6} erg cm{sup −3}; shape anisotropy: 1.07 × 10{sup 6} erg cm{sup −3}), with the easy axis lying out of plane, and a larger magnetic moment (6 μ{sub B}/f.u.) than bulk CuCr{sub 2}Se{sub 4}. - Highlights: • Crystallographically aligned, phase pure CuCr{sub 2}Se{sub 4} were synthesized. • The degree of alignment decreases with annealing time. • The films are ferromagnetic with the easy axis along the <111> direction. • The magnetization is larger than bulk CuCr{sub 2}Se{sub 4} or other CuCr{sub 2}Se{sub 4} films made to date.

  19. Order–disorder phenomena in layered CuCrSe{sub 2} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Gagor, A., E-mail: a.gagor@int.pan.wroc.pl; Gnida, D.; Pietraszko, A.

    2014-08-01

    The thermal motion of Cu{sup +} ions in a quasi-two dimensional copper ion conductor CuCrSe{sub 2} is studied in the vicinity of the order-disorder phase transition to superionic phase, basing on a single-crystal and powder X-ray diffraction, specific heat and electrical resistivity measurements. The copper ions gradually migrate with temperature decrease to empty tetrahedral sites reaching occupancy equilibrium in the disordered high-temperature phase at T{sub s} = 365 K. The copper migration between Cuα and Cuβ tetrahedral sites occurs through the neighboring, face-sharing octahedral holes. Disorder of Cu{sup +} ions brings perturbations in periodic potential of the crystal lattice providing additional scattering centers for electrons. - Graphical abstract: Copper migration within α and β sites. - Highlights: • Single crystals of CuCrSe{sub 2} have been grown by vapor transport. • Thermally activated motion of Cu{sup +} ions is analyzed from T = 295 up to 420 K. • An order–disorder phase transition at T{sub s} = 365 K leads to fast ion conducting state. • Interplay between lattice vibrations and Se polarizability accounts for Cu{sup +} hops. • Electrical resistivity near the T{sub s} shows two additional scattering centers.

  20. Evaluation of heavy metals (Cr, Fe, Ni, Cu, Zn, Cd, Pb and Hg) in water, sediments and water lily (Eichornia crassipes) from Jose Antonio Alzate dam; Evaluacion de metales pesados Cr, Fe, Ni, Cu, Zn, Cd, Pb y Hg en agua, sedimento y lirio acuatico (Eichhornia crassipes) de la Presa Jose Antonio Alzate, Estado de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Avila P, P

    1996-12-31

    Water, sediments and water lily (Eichornia crassipes) from the Jose Antonio Alzate Dam were analyzed in order to determine concentrations of chromium, iron, nickel, copper, zinc, cadmium, lead and mercury. Mercury, lead, chromium and iron were found in concentrations above permissible limits in water, and in high concentrations in sediments. Cadmium, nickel, copper and zinc never were found in concentrations above permissible limits in water. The highest concentrations of heavy metals in water lily were found in the root. Accumulation factors decreased in the following order: Zn> Cr> Fe> Ni> Cu> Pb> Hg and Cd. Statistical differences ({alpha} < 0.5) between the collection samples dates was observed. High correlations between metals concentrations in superficial water, sediment and water hyacinth were also observed. These correlations could indicate that the heavy metals studied here, are originated from a natural source such as sediments or from an industrial source. (Author).

  1. Comparative toxicity of VO3-, CrO42-, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+ to lettuce seedlings

    International Nuclear Information System (INIS)

    Berry, W.L.

    1978-01-01

    Lettuce seeds imbibed, germinated, and grown in a 0.1-strength modified Hoagland culture solution were subjected to a series of increasing concentrations of individual heavy metals up to and exceeding lethal levels. After an exposure of 5 days, seedlings were harvested, examined, and measured to determine toxic effects. A log--log plot of root length (yield) vs. heavy metal concentration was made for each metal to produce a dose response curve. The curves showed a growth plateau at low concentrations of the respective metals which was equivalent to the growth of the control. All metals inhibited root growth and caused lethal toxicity in the sub- and low-milliequivalent range. When concentrations of the tested metals exceeded their thresholds of acute toxicity, root growth was inhibited. In the zone of inhibition, between the acute toxic threshold and complete inhibition, the log--log dose response curves were approximately linear or were a series of linear steps. The threshold toxicity and the response slope were characteristic for each metal. Seedling lettuce showed a monophasic response to VO 3 - , Cu 2+ , and Zn 2+ ; a biphasic response to CrO 4 2 -, Mn 2+ , Ni 2+ , and Cd 2+ ; and a quadraphasic response to Co 2+ . The acute toxicity threshold on an equivalent basis increased according to the following sequence: Cd 2+ much less than VO 3 - 2+ 2+ 2+ 4 2- 2+ much less than Mn 2+ . On this basis, Cd 2+ is the most toxic of the trace elements tested

  2. A novel coping metal material CoCrCu alloy fabricated by selective laser melting with antimicrobial and antibiofilm properties.

    Science.gov (United States)

    Ren, Ling; Memarzadeh, Kaveh; Zhang, Shuyuan; Sun, Ziqing; Yang, Chunguang; Ren, Guogang; Allaker, Robert P; Yang, Ke

    2016-10-01

    The aim of this study was to fabricate a novel coping metal CoCrCu alloy using a selective laser melting (SLM) technique with antimicrobial and antibiofilm activities and to investigate its microstructure, mechanical properties, corrosion resistance and biocompatibility. Novel CoCrCu alloy was fabricated using SLM from a mixture of commercial CoCr based alloy and elemental Cu powders. SLM CoCr without Cu served as control. Antibacterial activity was analyzed using standard antimicrobial tests, and antibiofilm properties were investigated using confocal laser scanning microscope. Cu distribution and microstructure were determined using scanning electron microscope, optical microscopy and X-ray diffraction. Corrosion resistance was evaluated by potential dynamic polarization and biocompatibility measured using an MTT assay. SLM CoCrCu alloys were found to be bactericidal and able to inhibit biofilm formation. Other factors such as microstructure, mechanical properties, corrosion resistance and biocompatibility were similar to those of SLM CoCr alloys. The addition of appropriate amounts of Cu not only maintains normal beneficial properties of CoCr based alloys, but also provides SLM CoCrCu alloys with excellent antibacterial and antibiofilm capabilities. This material has the potential to be used as a coping metal for dental applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. The structural and electro-optical characteristics of AZO/Cr:Cu/AZO transparent conductive film

    International Nuclear Information System (INIS)

    Lin, Tien-Chai; Huang, Wen-Chang; Tsai, Fu-Chun

    2015-01-01

    A novel triple-layered transparent conductive film, AZO/Cr:Cu/AZO (ACCA), was presented in the paper. The structural and electro-optical properties of the ACCA film were discussed. The thickness of the middle metal layer was constant and those of the AZO layers were varied. The ACCA film shows an obvious ZnO (002) c-axis preferential growth. No diffraction peaks related to Cr and Cu were observed through x-ray diffraction analysis. The middle Cr:Cu layer showed a thickness of 8.16 nm with a continuous and amorphous structure by the observation of a high-resolution transmission electron microscopy (HR-TEM). For the electro-optical characteristic, a best figure of merit (FOM) value of 3.54 × 10 −3 Ω −1 with a corresponding transmittance of 85% was obtained at the thickness of 116 nm of ACCA film. The high FOM value of the film is due to the improvement of conductivity and small sacrifices of transparency. - Highlights: • A novel triple-layered transparent conductive film, AZO/Cr:Cu/AZO is developed. • Chromium is added to copper to reduce the oxidation–reduction reaction. • The film has a FOM of 3.54 × 10 −3 Ω −1 with a corresponding transmittance of 85%. • The Cr:Cu layer shows a continuous and amorphous structure

  4. The structural and electro-optical characteristics of AZO/Cr:Cu/AZO transparent conductive film

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Tien-Chai [Department of Electrical Engineering, Kun Shan University, No. 195, Kun-Da Road, Yung-Kang Dist., Tainan 71003, Taiwan, ROC (China); Huang, Wen-Chang, E-mail: wchuang@mail.ksu.edu.tw [Department of Electro-Optical Engineering, Kun Shan University, No. 195, Kun-Da Road, Yung-Kang Dist., Tainan 71003, Taiwan, ROC (China); Tsai, Fu-Chun [Department of Electro-Optical Engineering, Kun Shan University, No. 195, Kun-Da Road, Yung-Kang Dist., Tainan 71003, Taiwan, ROC (China)

    2015-08-31

    A novel triple-layered transparent conductive film, AZO/Cr:Cu/AZO (ACCA), was presented in the paper. The structural and electro-optical properties of the ACCA film were discussed. The thickness of the middle metal layer was constant and those of the AZO layers were varied. The ACCA film shows an obvious ZnO (002) c-axis preferential growth. No diffraction peaks related to Cr and Cu were observed through x-ray diffraction analysis. The middle Cr:Cu layer showed a thickness of 8.16 nm with a continuous and amorphous structure by the observation of a high-resolution transmission electron microscopy (HR-TEM). For the electro-optical characteristic, a best figure of merit (FOM) value of 3.54 × 10{sup −3} Ω{sup −1} with a corresponding transmittance of 85% was obtained at the thickness of 116 nm of ACCA film. The high FOM value of the film is due to the improvement of conductivity and small sacrifices of transparency. - Highlights: • A novel triple-layered transparent conductive film, AZO/Cr:Cu/AZO is developed. • Chromium is added to copper to reduce the oxidation–reduction reaction. • The film has a FOM of 3.54 × 10{sup −3} Ω{sup −1} with a corresponding transmittance of 85%. • The Cr:Cu layer shows a continuous and amorphous structure.

  5. Evaluation of heavy metals (Cr, Fe, Ni, Cu, Zn, Cd, Pb and Hg) in water, sediments and water lily (Eichornia crassipes) from Jose Antonio Alzate dam

    International Nuclear Information System (INIS)

    Avila P, P.

    1995-01-01

    Water, sediments and water lily (Eichornia crassipes) from the Jose Antonio Alzate Dam were analyzed in order to determine concentrations of chromium, iron, nickel, copper, zinc, cadmium, lead and mercury. Mercury, lead, chromium and iron were found in concentrations above permissible limits in water, and in high concentrations in sediments. Cadmium, nickel, copper and zinc never were found in concentrations above permissible limits in water. The highest concentrations of heavy metals in water lily were found in the root. Accumulation factors decreased in the following order: Zn> Cr> Fe> Ni> Cu> Pb> Hg and Cd. Statistical differences (α < 0.5) between the collection samples dates was observed. High correlations between metals concentrations in superficial water, sediment and water hyacinth were also observed. These correlations could indicate that the heavy metals studied here, are originated from a natural source such as sediments or from an industrial source. (Author)

  6. Phytoextraction of initial cutting of Salix matsudana for Cd and Cu.

    Science.gov (United States)

    Wang, Wen-Wen; Cheng, Liu Ke; Hao, Jie Wei; Guan, Xin; Tian, Xing-Jun

    2016-06-27

    Salix species are widely used as vegetation filters because of their flourishing root system and fast growth rate. However, studies have yet to determine whether the root system functions in vegetable filters with mixed heavy metal (HM) pollution or whether initial cutting participates in the phytoextraction of HMs. This study aims to determine the function of the root system and initial cutting as vegetation filters in the absorption and accumulation of Cd and Cu. Thick (>1 cm in diameter) and fine (phytoextraction capacity of plants. The initial cuttings could also absorb and accumulate HMs in the early growth stages of willow without roots. Cu inhibited the plant absorption and accumulation of Cd and promoted Cd transport to shoots. Cd inhibited the Cu absorption of the root system. Our study provided essential data regarding woody species as vegetation filters of HM pollution.

  7. Kinetic and thermodynamic aspects of Cu(II) and Cr(III) removal from aqueous solutions using rose waste biomass

    International Nuclear Information System (INIS)

    Iftikhar, Abdur Rauf; Bhatti, Haq Nawaz; Hanif, Muhammad Asif; Nadeem, Razyia

    2009-01-01

    Distillation waste of rose petals was used to remove Cu(II) and Cr(III) from aqueous solutions. The results demonstrated the dependency of metal sorption on pH, sorbent dose, sorbent size, initial bulk concentration, time and temperature. A dosage of 1 g/L of rose waste biomass was found to be effective for maximum uptake of Cu(II) and Cr(III). Optimum sorption temperature and pH for Cu(II) and Cr(III) were 303 ± 1 K and 5, respectively. The Freundlich regression model and pseudo-second-order kinetic model were resulted in high correlation coefficients and described well the sorption of Cu(II) and Cr(III) on rose waste biomass. At equilibrium q max (mg/g) of Cu(II) and Cr(III) was 55.79 and 67.34, respectively. The free energy change (ΔG o ) for Cu(II) and Cr(III) sorption process was found to be -0.829 kJ/mol and -1.85 kJ/mol, respectively, which indicates the spontaneous nature of sorption process. Other thermodynamic parameters such as entropy change (ΔS o ), enthalpy (ΔH o )and activation energy (ΔE) were found to be 0.604 J mol -1 K -1 , -186.95 kJ/mol and 68.53 kJ/mol, respectively for Cu(II) and 0.397 J mol -1 K -1 , -119.79 kJ/mol and 114.45 kJ/mol, respectively for Cr(III). The main novelty of this work was the determination of shortest possible sorption time for Cu(II) and Cr(III) in comparison to earlier studies. Almost over 98% of Cu(II) and Cr(III) were removed in only first 20 min at an initial concentration of 100 mg/L

  8. Antibacterial property of CuCrO{sub 2} nanopowders prepared by a self-combustion glycine nitrate process

    Energy Technology Data Exchange (ETDEWEB)

    Nien, Yung-Tang, E-mail: ytnien@nfu.edu.tw [Deparment of Materials Science and Engineering, National Formosa University, Yunlin, 63201, Taiwan (China); Hu, Mon-Ru [Deparment of Materials Science and Engineering, National Formosa University, Yunlin, 63201, Taiwan (China); Chiu, Te-Wei [Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei, 10608, Taiwan (China); Chu, Jaw-Shiow [Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu, 30062, Taiwan (China)

    2016-08-15

    Porous CuCrO{sub 2} nanopowders were prepared via glycine nitrate process (GNP) at 175 °C in ambient air. The X-ray diffraction patterns showed a pure delafossite phase of CuCrO{sub 2} with numerous broad peaks, indicating a crystallite size of approximately 20 nm. The surface area of the CuCrO{sub 2} nanopowders was larger than 50 m{sup 2}/g, nearly 100 times greater than that of bulk powders (0.47 m{sup 2}/g). Pathogenic Gram-negative bacteria Escherichia coli (E. coli) were chosen as the antibacterial evaluation indicators for both the nanopowders and bulk powders. The results showed that 1750 ppm nanopowders inhibited the growth of E. coli. As a control, the bulk powders showed a normal growth profile. The antibacterial property of the CuCrO{sub 2} nanopowders can be attributed to the extremely large surface area, which induces rapid release of Cu ions and strong adhesion of nanopowders to bacteria. - Highlights: • CuCrO{sub 2} nanopowders was prepared by low-temperature glycine nitrate process. • 1250–1500 ppm of CuCrO{sub 2} nanopowders were found to depress the growth of Escherichia coli. • Bulk powders by the solid state reaction exhibited no antibacterial property. • The antibacterial property of nanopowders was attributed to rapid Cu ion releases. • Heavy adhesion of nanopowders to bacteria also resulted in antibacterial property.

  9. Synthesis, characterization and photocatalytic activity of cubic-like CuCr2O4 for dye degradation under visible light irradiation

    International Nuclear Information System (INIS)

    Yuan, Wenhui; Liu, Xiaoxia; Li, Li

    2014-01-01

    Graphical abstract: Hydrothermal synthesis method was applied for preparation of cubic-like CuCr 2 O 4 spinel nanoparticles without template. The synthesized cubic-like CuCr 2 O 4 shows excellent photocatalytic activity for degradation of RhB and MB cationic dyes but not for MO anionic dye in the presence of H 2 O 2 under visible light irradiation. - Highlights: • The cubic-like CuCr 2 O 4 spinel nanoparticles were successfully synthesized via the hydrothermal synthesis method. • The calcination temperature has a great influence on the morphology, particle size and photocatalytic activity of CuCr 2 O 4 . • The pH at the point of zero charge (pH pzc ) of the CuCr 2 O 4 calcined at 600 °C is about 4.52. • The cubic-like CuCr 2 O 4 calcined at 600 °C exhibits excellent photocatalytic activity for RhB and MB in the presence of H 2 O 2 under visible-light irradiation. - Abstract: CuCr 2 O 4 nanoparticles with cubic-like morphology were prepared via hydrothermal synthesis method without template. The CuCr 2 O 4 samples were characterized by thermogravimetry and differential scanning calorimetry (TG–DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (DRS) and Zeta potentials, respectively. The results indicated that cubic-like CuCr 2 O 4 could be successfully synthesized by calcining the precursor at 600 °C, and the calcination temperature greatly influenced the morphology and optical performance of CuCr 2 O 4 . The pH at the point of zero charge (pH pzc ) of the CuCr 2 O 4 calcined at 600 °C was about 4.52. The photocatalytic activity of CuCr 2 O 4 was evaluated for degradation of rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) in the presence of H 2 O 2 under visible light irradiation and the effects of the calcination temperature, dosage of photocatalyst, etc., on photocatalytic activity were studied in detail. The photocatalytic results

  10. Preliminary assessment of metal-porcelain bonding strength of CoCrW alloy after 3 wt.% Cu addition

    International Nuclear Information System (INIS)

    Lu, Yanjin; Zhao, Chaoqian; Ren, Ling; Guo, Sai; Gan, Yiliang; Yang, Chunguang; Wu, Songquan; Lin, Junjie; Huang, Tingting; Yang, Ke; Lin, Jinxin

    2016-01-01

    In this work, a novel Cu-bearing CoCrW alloy fabricated by selective laser melting for dental application has been studied. For its successful application, the bonding strength of metal-porcelain is essential to be systematically investigated. Therefore, the aim of this study was to evaluate the metal-porcelain bonding strength of CoCrWCu alloy by three-point bending test, meanwhile the Ni-free CoCrW alloy was used as control. The oxygen content was investigated by an elemental analyzer; X-ray photoelectron spectroscopy (XPS) was used to analyze the surface chemical composition of CoCrW based alloy after preoxidation treatment; the fracture mode was investigated by X-ray energy spectrum analysis (EDS) and scanning electron microscope (SEM). Result from the oxygen content analysis showed that the content of oxygen dramatically increased after the Cu addition. And the XPS suggested that Co-oxidation, Cr_2O_3, CrO_2, WO_3, Cu_2O and CuO existed on the preoxidated surface of the CoCrWCu alloy; the three-point bending test showed that the bonding strength of the CoCrWCu alloy was 43.32 MPa, which was lower than that of the CoCrW group of 47.65 MPa. However, the average metal-porcelain bonding strength is significantly higher than the minimum value in the ISO 9693 standard. Results from the SEM images and EDS indicated that the fracture mode of CoCrWCu-porcelain was mixed between cohesive and adhesive. Based on the results obtained in this study, it can be indicated that the Cu-bearing CoCrW alloy fabricated by the selective laser melting is a promising candidate for use in dental application. - Highlights: • The bonding strength of metal-porcelain was slightly decreased with Cu addition; • Cu not only led to promote the diffusion of O and W element but also inhibited the diffusivity of Co in the outward direction; • The changed oxidation behavior resulted in lowering the bonding strength;

  11. Preliminary assessment of metal-porcelain bonding strength of CoCrW alloy after 3 wt.% Cu addition

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yanjin; Zhao, Chaoqian [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155Yangqiao Road West, Fuzhou (China); Ren, Ling [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang (China); Guo, Sai; Gan, Yiliang [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155Yangqiao Road West, Fuzhou (China); Yang, Chunguang [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang (China); Wu, Songquan; Lin, Junjie; Huang, Tingting [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155Yangqiao Road West, Fuzhou (China); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang (China); Lin, Jinxin, E-mail: franklin@fjirsm.ac.cn [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155Yangqiao Road West, Fuzhou (China)

    2016-06-01

    In this work, a novel Cu-bearing CoCrW alloy fabricated by selective laser melting for dental application has been studied. For its successful application, the bonding strength of metal-porcelain is essential to be systematically investigated. Therefore, the aim of this study was to evaluate the metal-porcelain bonding strength of CoCrWCu alloy by three-point bending test, meanwhile the Ni-free CoCrW alloy was used as control. The oxygen content was investigated by an elemental analyzer; X-ray photoelectron spectroscopy (XPS) was used to analyze the surface chemical composition of CoCrW based alloy after preoxidation treatment; the fracture mode was investigated by X-ray energy spectrum analysis (EDS) and scanning electron microscope (SEM). Result from the oxygen content analysis showed that the content of oxygen dramatically increased after the Cu addition. And the XPS suggested that Co-oxidation, Cr{sub 2}O{sub 3}, CrO{sub 2}, WO{sub 3}, Cu{sub 2}O and CuO existed on the preoxidated surface of the CoCrWCu alloy; the three-point bending test showed that the bonding strength of the CoCrWCu alloy was 43.32 MPa, which was lower than that of the CoCrW group of 47.65 MPa. However, the average metal-porcelain bonding strength is significantly higher than the minimum value in the ISO 9693 standard. Results from the SEM images and EDS indicated that the fracture mode of CoCrWCu-porcelain was mixed between cohesive and adhesive. Based on the results obtained in this study, it can be indicated that the Cu-bearing CoCrW alloy fabricated by the selective laser melting is a promising candidate for use in dental application. - Highlights: • The bonding strength of metal-porcelain was slightly decreased with Cu addition; • Cu not only led to promote the diffusion of O and W element but also inhibited the diffusivity of Co in the outward direction; • The changed oxidation behavior resulted in lowering the bonding strength;.

  12. Adsorption of Pb, Cd, Zn, Cu and Hg ions on Formaldehyde and ...

    African Journals Online (AJOL)

    Adsorption of Pb(II), Cd(II), Zn(II), Cu(II) and Hg(II) ions on formaldehyde and Pyridine modified bean husks were determined. The adsorption capacity of formaldehyde modified bean husks (mg/g) was: Pb2+, 5.01; Cd2+, 3.63; Zn2+, 2.18; Hg2+, 1.82; Cu2+, 1.58 and that of pyridine modified bean husk was: Hg2+, 6.92; Cd2+ ...

  13. Influence of divalent metal on the decomposition products of hydrotalcite-like ternary systems MII–Al–Cr (MII = Zn, Cd)

    International Nuclear Information System (INIS)

    Pérez, M.R.; Crespo, I.; Ulibarri, M.A.; Barriga, C.; Rives, V.; Fernández, J.M.

    2012-01-01

    Highlights: ► LDHs M II –Al–Cr (M = Zn, Cd) with Cr in the layer or interlayer have been prepared. ► LDHs Zn–Al or Zn–Cr decompose by heating forming ZnO and ZnAl 2 O 4 or ZnO and ZnCr 2 O 4 . ► LDHs Zn–Al–Cr give rise to the formation of ZnO and the mixed spinel ZnAl 2−x Cr x O 4 . ► LDH Cd–Al–Cr shows the formation of CdO, CdCr 2−x Al x O 4 , and (Al, Cr) 2 O 3 mixed oxide. ► Calcination of the CdAl–CrO 4 give rise to (Al, Cr) 2 O 3 as the majority phase. - Abstract: Layered double hydroxides (LDHs) containing M II , Al III , and Cr III in the brucite-like layers (M = Cd, Zn) with different starting Al/Cr molar ratios and nitrate/carbonate as the interlayer anion have been prepared following the coprecipitation method at a constant pH: Zn II –Al III –Cr III –CO 3 2− at pH = 10, and Cd II –Al III –Cr III –NO 3 − at pH = 8. Two additional M II ,Al III –LDH samples (M = Cd, Zn) with chromate ions (CrO 4 2− ) in the interlayer have been prepared by ionic exchange at pH = 9 and 8, respectively, starting from M II –Al III –NO 3 − . The samples have been characterised by absorption atomic spectrometry, powder X-ray diffraction (PXRD), FT-IR spectroscopy and transmission electron microscopy (TEM). Their thermal stability has been assessed by DTA-TG and mass spectrometric analysis of the evolved gases. The PXRD patterns of the solids calcined at 800 °C show diffraction lines corresponding to ZnO and ZnAl 2−x Cr x O 4 for the Zn-containing samples, and diffraction lines attributed to CdO and CdCr 2 O 4 and (Al,Cr) 2 O 3 for the Cd-containing ones. Additionally a minority oxide, Cd 2 CrO 5 , is observed to Cd II –Al III –LDH samples with chromate ions in the interlayer.

  14. The role of Cd and Ga in the Cu(In,Ga)S2/CdS heterojunction studied with X-ray spectroscopic methods

    International Nuclear Information System (INIS)

    Johnson, Benjamin E.

    2010-01-01

    Photovoltaic cells with the structure Glass/Mo/Cu(In,Ga)S 2 /CdS/i-ZnO/n+-ZnO are currently among the most successful and promising thin-layer solar cells. In this system, the Cu(In,Ga)S 2 (CIS) acts as the absorber, the CdS as the buffer layer and the ZnO as the window layer. The goal of this work is the investigation of the Cu(In,Ga)S 2 /CdS semiconductor heterojunction both as a component of the solar cell and as a separate material system. The characteristics of this junction were investigated both during junction formation through chemical bath deposition (CBD) and after the junction was completed. It is currently thought that the Cu(In,Ga)S 2 /CdS junction is responsible for several different properties of the solar cell: lattice matching and band offset optimization between the absorber and window layer and chemical passivation of the absorber surface by the CBD-CdS process on CIS which acts to reduce the surface defect density. The Cd may also pin the Fermi Level on the CIS surface or cause a type inversion of the absorber surface from p-type to n-type. In order to investigate the junction several new methods were used along side the conventional methods of X-ray, Ultraviolet and Inverse Photoelectron Spectroscopy. These were Near-UV Constant Final State Yield Spectroscopy for the measurement of the valence band offset at the interface between CIS and CdS and Near Edge X-ray Absorption Fine Structure to follow the development of the Cu(In,Ga)S 2 conduction band edge with increasing Ga concentration. Additionally, the advantages and disadvantages of the established and new methods were compared and discussed. It was discovered that the deposition of CdS neither pins the Fermi Level on the CIS surface at a position important for the solar cell, nor does it dope the absorber surface, although the deposition does lead to the formation of a Cd-containing CIS surface layer (CIS:Cd). Because this surface layer is not soluble in HCl it cannot be CdS as this is

  15. A new colorimetric chemosensors for Cu{sup 2+} and Cd{sup 2+} ions detection: Application in environmental water samples and analytical method validation

    Energy Technology Data Exchange (ETDEWEB)

    Tekuri, Venkatadri; Trivedi, Darshak R., E-mail: darshak_rtrivedi@yahoo.co.in

    2017-06-15

    A new heterocyclic thiophene-2-caboxylic acid hydrazide based chemosensor R1 to R4 were designed, synthesized and characterized by various spectroscopic techniques like FT-IR, UV-Vis, {sup 1}H NMR, {sup 13}C NMR, Mass and SC-XRD. The chemosensor R3 showed a significant color change from colorless to yellow in the presence of Cu{sup 2+} ions and chemosensor R4 showed a significant color change from colorless to yellow in the presence of Cd{sup 2+} ions over the other tested cations such as Cr{sup 3+}, Mn{sup 2+}, Fe{sup 2+}, Fe{sup 3+}, Co{sup 2+}, Ni{sup 2+}, Zn{sup 2+}, Ag{sup 2+}, Al{sup 3+}, Pb{sup 2+}, Hg{sup 2+}, K{sup +}, Ca{sup 2+} and Mg{sup 2+}. The high selective and sensitivity of R3 towards Cu{sup 2+} and R4 towards Cd{sup 2+} ions was confirmed by UV-Vis spectroscopic study. The R3 showed a red shift in the presence of Cu{sup 2+} ions by Δλ{sub max} 67 nm and R4 showed a red shift in the presence of Cd{sup 2+} ions by Δλ{sub max} 105 nm in the absorption spectrum. The binding stoichiometric ratio of the complex between R3 - Cu{sup 2+} and R4 - Cd{sup 2+} ions have been found to be 1:1 using the B-H plot. Under optimized experimental conditions, the R3 and R4 exhibits a dynamic linear absorption response range, from 0 to 50 μM for Cu{sup 2+} ions and 0 to 30 μM for Cd{sup 2+} ions, with the detection limit of 2.8 × 10{sup −6} M for Cu{sup 2+} and 2.0 × 10{sup −7} M for Cd{sup 2+} ions. The proposed analytical method for the quantitative determination of Cu{sup 2+} and Cd{sup 2+} ions was validated and successfully applied for the environmental samples with good precision and accuracy. - Highlights: • Detection of Cu{sup 2+} and Cd{sup 2+} ions has gained significance by virtue of its key role in biological and environmental science. • The R3 and R4 showed instantaneous color change from colorless to yellow in the presence of Cu{sup 2+} and Cd{sup 2+} ions respectively. • The proposed detection methods were validated and

  16. NaCl protects against Cd and Cu-induced toxicity in the halophyte Atriplex halimus

    Energy Technology Data Exchange (ETDEWEB)

    Bankaji, I.; Sleimi, N.; Gómez-Cadenas, A.; Pérez-Clemente, R.M.

    2016-07-01

    The objective of the present work was to evaluate the extent of Cd- and Cu-induced oxidative stress and the antioxidant response triggered in the halophyte species Atriplex halimus after metallic trace elements exposure. Plants were treated for one month with Cd2+ or Cu2+ (400 µM) in the absence or presence of 200 mM NaCl in the irrigation solution. The interaction between salinity and heavy metal stress was analyzed in relation to plant growth, tissue ion contents (Na+, K+ and Mg2+), oxidative damage and antioxidative metabolism. Data indicate that shoot and root weight significantly decreased as a consequence of Cd2+- or Cu2+-induced stress. Metallic stress leads to unbalanced nutrient uptake by reducing the translocation of K+ and Mg2+ from the root to the shoot. The levels of malondialdehyde increased in root tissue when Cd, and especially Cu, were added to the irrigation solution, indicating that oxidative damage occurred. Results showed that NaCl gave a partial protection against Cd and Cu induced toxicity, although these contaminants had distinct influence on plant physiology. It can be concluded that salinity drastically modified heavy metal absorption and improved plant growth. Salinity also decreased oxidative damage, but differently in plants exposed to Cd or Cu stress.

  17. Qualitative analysis of As, Ba, Cd, Cr, Zn, Fe, Mn, K, Hg, Pb y Cu, as constituents of Amatitlan Lake sediment by XRF

    International Nuclear Information System (INIS)

    Beltran, P.A.E.; Morales, E.A.

    1987-10-01

    Samples of fifteen sampling points were analyzed. Molybdenum X-ray tube with secondary excitation assembly, SiLi detector and deconvolution software AXIL were employed; self-standardization method based upon incoherent ratio was used for quantitative analysis of some elements. Ca, P, S, Ti, Mn, Fe, Cr, Zn, Cu, Ni, Ga, As, Pb, Ge, Sr and Pb, were found. As, Pb and Cu concentrations lower than 109 mg/lt, 119 mg/lt, and 500mg/lt, respectively, were measured. Hg was not detected. (author)

  18. Complement receptors type 1 (CR1, CD35) and 2 (CR2, CD21) cooperate in the binding of hydrolyzed complement factor 3 (C3i) to human B lymphocytes

    DEFF Research Database (Denmark)

    Leslie, Robert Graham Quinton; Prodinger, Wolfgang Maria; Nielsen, Claus Henrik

    2003-01-01

    The C3b-binding receptor, CR1/CD35, supports CR2/CD21-mediated activation of complement by human B lymphocytes, possibly by associating with CR2 to promote or stabilize the binding of hydrolyzed C3 (C3i), the primary component of the AP convertase, C3i-Bb. To evaluate this hypothesis, we examined...... the uptake kinetics and binding equilibria for C3i dimer interaction with human blood cells in the absence and presence of CR1- and CR2-blocking mAb. C3i displayed dual uptake kinetics to B lymphocytes, comprising of rapid binding to CR1 and slower binding to CR2. The forward rate constants (k(1)) for CR1...... and CR2, operating independently, differed ca. 9-fold (k(1)=193+/-9.4 and 22.2+/-6.0 x 10(3) M(-1)s(-1), respectively). Equilibrium binding of C3i to B lymphocytes was also complex, varying in strength by ca. 13-fold over the C3i concentration range examined. The maximum association constant (K(a, max...

  19. Cd, Zn, Ni and Cu in the Indian Ocean

    NARCIS (Netherlands)

    Saager, Paul M.; Baar, Hein J.W. de; Howland, Robin J.

    1992-01-01

    Vertical profiles of dissolved Cd, Zn, Ni and Cu in the Northwest Indian Ocean (Arabian Sea) exhibit a nutrient type distribution also observed in other oceans. The area is characterized by strong seasonal upwelling and a broad oxygen minimum zone in intermediate waters. However, neither Cd, Zn, Ni

  20. The crystal structure of Cu9.1(1)TeSb3, a stuffed derivative of Cr3Si

    DEFF Research Database (Denmark)

    Søtofte, Inger; Makovicky, E.; Karup-Møller, Sven

    1998-01-01

    The intermetallic compound Cu9.1(1)TeSb3 prepared at 973 K is an ordered member of the solid solution Cu64Te31Sb5-Cu70Te8Sb22 which also exists, for more limited composition ranges, between 673 K and 1173 K. It is a stuffed derivative of the structure type A15 (Cr3Si). Te is surrounded by twelve 3....../4-occupied Cu-positions in the vertices of a cubically-deformed icosahedron (Cu-Te = 2.614 Å) which itself is nested in an Sb-icosahedron (Cu-Sb = 2.777 Å (x2) and 2.603 Å). The Sb array corresponds to the Cr array in Cr3Si....

  1. Relationship between firewood usage and urinary Cr, Cu and As in informal areas of Cape Town.

    Science.gov (United States)

    Dalvie, Mohamed Aqiel; Africa, Algernon; Naidoo, Sivapregasen

    2013-09-03

    The study investigated whether wood usage by informal food vendors and household residents in Cape Town results in the absorption of arsenic (As), chromium (Cr) and copper (Cu) owing to release of these metals in the burning of chromated copper arsenate (CCA)-treated wood. The participants (N=78) selected included an equal number of food vendors and non-vendors from 2 informal settlements. All participants answered a questionnaire concerning exposure and were tested for urinary Cr, Cu and As, while the urine of 29 participants was also tested for toxic As (As(tox)). Multivariate analysis showed that the time spent in close proximity to the wood, as well as the quantity of wood used for cooking and for household use, was weakly positively associated with urinary levels of As, Cr and the sum of As, Cr and Cu. The study provides evidence that use of wood likely to contain CCA as a fuel for informal food outlets and household purposes may increase the absorption of inorganic As, Cu and Cr.

  2. Effect of Cu on microstructure, mechanical properties, corrosion resistance and cytotoxicity of CoCrW alloy fabricated by selective laser melting.

    Science.gov (United States)

    Lu, Yanjin; Ren, Ling; Xu, Xiongcheng; Yang, Yang; Wu, Songquan; Luo, Jiasi; Yang, Mingyu; Liu, Lingling; Zhuang, Danhong; Yang, Ke; Lin, Jinxin

    2018-05-01

    In the study, CoCrWCu alloys with differing Cu content (2, 3, 4 wt%) were prepared by selective laser melting using mixture powders consisting of CoCrW and Cu, aiming at investigating the effect of Cu on the microstructures, mechanical properties, corrosion behavior and cytotoxicity. The SEM observations indicated that the Cu content up to 3 wt% caused the Si-rich precipitates to segregate along grain boundaries and in the grains, and EBSD analysis suggested that the Cu addition decreased the recrystallization degree and increased the grain diameter and fraction of big grains. The tensile tests found that the increasing Cu content led to a decrease of mechanical properties compared with Cu-free CoCrW alloy. The electrochemical tests revealed that the addition of Cu shifted the corrosion potential toward nobler positive, but increased the corrosion current density. Also, a more protective passive film was formed when 2 wt% Cu content was added, but the higher Cu content up to 3 wt% was detrimental to the corrosion resistance. It was noted that there was no cytotoxicity for Cu-bearing CoCrW alloys to MG-63 cell and the cells could spread well on the surfaces of studied alloys. Meanwhile, the Cu-bearing CoCrW alloy exhibited an excellent antibacterial performance against E.coli when Cu content was up to 3 wt%. It is suggested that the feasible fabrication of Cu-bearing CoCrW alloy by SLM using mixed CoCrW and Cu powders is a promising candidate for use in antibacterial oral repair products. This current study also can aid in the further design of antibacterial Cu-containing CoCrW alloying powders. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. CrCuAgN PVD nanocomposite coatings: Effects of annealing on coating morphology and nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xingguang, E-mail: xingguangliu1@gmail.com [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom); Iamvasant, Chanon, E-mail: ciamvasant1@sheffield.ac.uk [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom); Liu, Chang, E-mail: chang.liu@sheffield.ac.uk [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom); Matthews, Allan, E-mail: allan.matthews@manchester.ac.uk [Pariser Building - B24 ICAM, School of Materials, The University of Manchester, Manchester, M13 9PL (United Kingdom); Leyland, Adrian, E-mail: a.leyland@sheffield.ac.uk [Department of Materials Science and Engineering, Sir Robert Hadfield Building, The University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)

    2017-01-15

    Highlights: • Coatings with nitrogen content up to 16 at.% exhibit a metallic Cr solid solution, even after post-coat annealing at 300 °C and 500 °C. • At higher N/Cr atomic ratios (approaching Cr{sub 2}N stoichiometry), chromium was still inclined to exist in solid solution with nitrogen, rather than as a ceramic nitride phase, even after annealing at 500 °C. • Transportation of Cu and Ag to the surface depends on annealing temperature, annealing duration, nitrogen concentration and ‘global’ Cu + Ag concentration. • Incorporation of copper appears to be a powerful strategy to enhance Ag mobility at low concentration (∼3 at.% Ag in this study) under moderately high service temperature. • A significant decrease in friction coefficient was obtained at room temperature after annealing, or during sliding wear testing at elevated temperature. - Abstract: CrCuAgN PVD nanocomposite coatings were produced using pulsed DC unbalanced magnetron sputtering. This investigation focuses on the effects of post-coat annealing on the surface morphology, phase composition and nanostructure of such coatings. In coatings with nitrogen contents up to 16 at.%, chromium exists as metallic Cr with N in supersaturated solid solution, even after 300 °C and 500 °C post-coat annealing. Annealing at 300 °C did not obviously change the phase composition of both nitrogen-free and nitrogen-containing coatings; however, 500 °C annealing resulted in significant transformation of the nitrogen-containing coatings. The formation of Ag aggregates relates to the (Cu + Ag)/Cr atomic ratio (threshold around 0.2), whereas the formation of Cu aggregates relates to the (Cu + Ag + N)/Cr atomic ratio (threshold around 0.5). The primary annealing-induced changes were reduced solubility of Cu, Ag and N in Cr, and the composition altering from a mixed ultra-fine nanocrystalline and partly amorphous phase constitution to a coarser, but still largely nanocrystalline structure. It was also

  4. Lattice parameter values and phase transitions for the Cu2Cd1-zMn zGeSe4 and Cu2Cd1-zFe zGeSe4 alloys

    International Nuclear Information System (INIS)

    Quintero, E.; Tovar, R.; Quintero, M.; Delgado, G.E.; Morocoima, M.; Caldera, D.; Ruiz, J.; Mora, A.E.; Briceno, M.; Fernandez, J.L.

    2007-01-01

    X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu 2 Cd 1-z Mn z GeSe 4 and Cu 2 Cd 1-z Fe z GeSe 4 alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. The effect of the annealing temperature and cooling rate to room temperature are discussed. For the Cu 2 Cd 1-z Fe z GeSe 4 system, only two single solid phase fields, the tetragonal stannite α and the wurtz-stannite δ structures were found to occur in the diagram. For the Cu 2 Cd 1-z Mn z GeSe 4 system, in addition to the tetragonal stannite α and the wurtz-stannite δ phases, MnSe was found to exist in the diagram. The DTA experiments showed that the cooling curves for both systems exhibited effects of undercooling

  5. Prosopis juliflora--a green solution to decontaminate heavy metal (Cu and Cd) contaminated soils.

    Science.gov (United States)

    Senthilkumar, P; Prince, W S P M; Sivakumar, S; Subbhuraam, C V

    2005-09-01

    Soil and plant samples (root and shoot) of Prosopis juliflora were collected in the vicinity of metal based foundry units in Coimbatore and assessed for their heavy metal content (Cu and Cd) to ascertain the use of P. juliflora as a green solution to decontaminate soils contaminated with Cu and Cd. The results showed that Cu and Cd content was much higher in plant components compared to their extractable level in the soil. Furthermore, there exist a strong correlation between the distance of the sources of industrial units and accumulation of heavy metals in plants. Accumulation of Cd in roots is comparatively higher than that of shoots. However, in case of Cu no such clear trend is seen. Considering the accumulation efficiency and tolerance of P. juliflora to Cd and Cu, this plant can be explored further for the decontamination of metal polluted soils. On the other hand, in view of heavy metal accumulate the practice of providing foliage and pods as fodder for live stock should be avoided.

  6. Rapid adsorption of Pb, Cu and Cd from aqueous solutions by β-cyclodextrin polymers

    Science.gov (United States)

    He, Junyong; Li, Yulian; Wang, Chengming; Zhang, Kaisheng; Lin, Dongyue; Kong, Lingtao; Liu, Jinhuai

    2017-12-01

    Removing heavy metals from aqueous solutions has drawn more and more attentions these years because of their serious global health challenge to human society. To develop an adsorbent with low-cost and high-efficiency for removal of heavy metals (HMs), β-cyclodextrin (β-CD) polymers crosslinked with rigid aromatic groups were prepared and used for lead (Pb), copper (Cu) and cadmium (Cd) removal for the first time. The negatively charged β-CD polymers with large BET surface area were suitable to be used in HMs adsorption. The adsorption process completed in 5 min was well fit by Freundlich isotherm model and pseudo-second-order model. The intraparticle diffusion model was also appropriate to describe the adsorption of Pb, Cu and Cd on β-CD polymer. The maximum of adsorption capacities at 25 °C for Pb, Cu and Cd were 196.42, 164.43 and 136.43 mg/g when the initial concentration was 200 mg/L. The HMs adsorption process on the surface of β-CD polymer was an endothermic and spontaneous process. Both of the electrostatic interaction and distribution of Pb, Cu and Cd species influenced the adsorption process at different pH values. The order of removal efficiencies in multi-component adsorption for the three metal ions were Pb > Cu > Cd. The adsorption mechanisms were H+ ions on hydroxyl groups exchanged with heavy metal ions and electrostatic interactions. This study indicated that β-CD polymers could be developed into effective adsorbents for rapid removal of heavy metals.

  7. Thermodynamic properties of the solid solutions CuCr/sub 2/S/sub 4/ in Cu/sub 1///sub 2/M/sub 1///sub 2/Cr/sub 2/S/sub 4/ (M=Ga, In)

    Energy Technology Data Exchange (ETDEWEB)

    Titov, V.V.; Gordeev, I.V.; Kesler, Y.A.; Shchelkotunov, V.A.; Tret' yakov, Y.D.

    1985-09-01

    Using an adiabatic calorimeter and a quartz dilatometer, the temperature dependences of the heat capacity for the solid solutions CuCr/sub 2/S/sub 4/ in Cu/sub 1///sub 2/M/sub 1///sub 2/Cr/sub 2/S/sub 4/ (M - Ga, In) were determined, the different components of the heat capacity were evaluated, and the thermodynamic parameters of the magnetic transformation were calculated.

  8. Effect of heat treatments on precipitate microstructure and mechanical properties of a CuCrZr alloy

    DEFF Research Database (Denmark)

    Edwards, D.J.; Singh, Bachu Narain; Tähtinen, S.

    2007-01-01

    The precipitate microstructure of prime aged CuCrZr was coarsened by overaging to see if the larger precipitates could prevent the initiation of plastic flow localization in irradiated CuCrZr. A number of tensile and fracture toughness specimens of prime aged CuCrZr alloy were given overaging...... carried out at 293, 333 and 573 K. Transmission electron microscopy was used to investigate the effects of overaging, subsequent irradiation and the effect of deformation. The results indicate that the overaging treatment of 873 K for 1 h produced a precipitate microstructure that improved the plastic...

  9. Nanostructural evolution of Cr-rich precipitates in a Cu-Cr-Zr alloy during heat treatment studied by 3 dimensional atom probe

    DEFF Research Database (Denmark)

    Hatakeyama, Masahiko; Toyama, Takeshi; Nagai, Yasuyoshi

    2008-01-01

    Nanostructural evolution of Cr (Cr-rich) precipitates in a Cu-0.78%Cr-0.13%Zr alloy has been studied after aging and overaging (reaging) by laser assisted local electrode 3 dimensional atom probe (Laser-LEAP). This material is a candidate for the first wall and divertor components of future fusion...

  10. Influence of Cu Content on the Microstructure and Mechanical Properties of Cr-Cu-N Coatings

    Directory of Open Access Journals (Sweden)

    Ji Cheng Ding

    2018-01-01

    Full Text Available The Cr-Cu-N coatings with various Cu contents (0–25.18 (±0.17 at.% were deposited on Si wafer and stainless steel (SUS 304 substrates in reactive Ar+N2 gas mixture by a hybrid coating system combining pulsed DC and RF magnetron sputtering techniques. The influence of Cu content on the coating composition, microstructure, and mechanical properties was investigated. The microstructure of the coatings was significantly altered by the introduction of Cu. The deposited coatings exhibit solid solution structure with different compositions in all of the samples. Addition of Cu is intensively favored for preferred orientation growth along (200 direction by restricting in (111 direction. With increasing Cu content, the surface and cross-sectional morphology of coatings were changed from triangle cone-shaped, columnar feature to broccoli-like and compact glassy microstructure, respectively. The mechanical properties including the residual stress, nanohardness, and toughness of the coatings were explored on the basis of Cu content. The highest hardness was obtained at the Cu content of 1.49 (±0.10 at.%.

  11. Manufacturing and High Heat Flux Testing of Brazed Flat-Type W/CuCrZr Plasma Facing Components

    Science.gov (United States)

    Lian, Youyun; Liu, Xiang; Feng, Fan; Chen, Lei; Cheng, Zhengkui; Wang, Jin; Chen, Jiming

    2016-02-01

    Water-cooled flat-type W/CuCrZr plasma facing components with an interlayer of oxygen-free copper (OFC) have been developed by using vacuum brazing route. The OFC layer for the accommodation of thermal stresses was cast onto the surface of W at a temperature range of 1150 °C-1200 °C in a vacuum furnace. The W/OFC cast tiles were vacuum brazed to a CuCrZr heat sink at 940 °C using the silver-free filler material CuMnSiCr. The microstructure, bonding strength, and high heat flux properties of the brazed W/CuCrZr joint samples were investigated. The W/Cu joint exhibits an average tensile strength of 134 MPa, which is about the same strength as pure annealed copper. High heat flux tests were performed in the electron beam facility EMS-60. Experimental results indicated that the brazed W/CuCrZr mock-up experienced screening tests of up to 15 MW/m2 and cyclic tests of 9 MW/m2 for 1000 cycles without visible damage. supported by National Natural Science Foundation of China (No. 11205049) and the National Magnetic Confinement Fusion Science Program of China (No. 2011GB110004)

  12. The role of Cd and Ga in the Cu(In,Ga)S{sub 2}/CdS heterojunction studied with X-ray spectroscopic methods

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Benjamin E.

    2010-08-15

    Photovoltaic cells with the structure Glass/Mo/Cu(In,Ga)S{sub 2}/CdS/i-ZnO/n+-ZnO are currently among the most successful and promising thin-layer solar cells. In this system, the Cu(In,Ga)S{sub 2} (CIS) acts as the absorber, the CdS as the buffer layer and the ZnO as the window layer. The goal of this work is the investigation of the Cu(In,Ga)S{sub 2}/CdS semiconductor heterojunction both as a component of the solar cell and as a separate material system. The characteristics of this junction were investigated both during junction formation through chemical bath deposition (CBD) and after the junction was completed. It is currently thought that the Cu(In,Ga)S{sub 2}/CdS junction is responsible for several different properties of the solar cell: lattice matching and band offset optimization between the absorber and window layer and chemical passivation of the absorber surface by the CBD-CdS process on CIS which acts to reduce the surface defect density. The Cd may also pin the Fermi Level on the CIS surface or cause a type inversion of the absorber surface from p-type to n-type. In order to investigate the junction several new methods were used along side the conventional methods of X-ray, Ultraviolet and Inverse Photoelectron Spectroscopy. These were Near-UV Constant Final State Yield Spectroscopy for the measurement of the valence band offset at the interface between CIS and CdS and Near Edge X-ray Absorption Fine Structure to follow the development of the Cu(In,Ga)S{sub 2} conduction band edge with increasing Ga concentration. Additionally, the advantages and disadvantages of the established and new methods were compared and discussed. It was discovered that the deposition of CdS neither pins the Fermi Level on the CIS surface at a position important for the solar cell, nor does it dope the absorber surface, although the deposition does lead to the formation of a Cd-containing CIS surface layer (CIS:Cd). Because this surface layer is not soluble in HCl it cannot

  13. Feasibility of constructed wetland planted with Leersia hexandra Swartz for removing Cr, Cu and Ni from electroplating wastewater.

    Science.gov (United States)

    You, Shao-Hong; Zhang, Xue-Hong; Liu, Jie; Zhu, Yi-Nian; Gu, Chen

    2014-01-01

    As a low-cost treatment technology for effluent, the constructed wetlands can be applied to remove the heavy metals from wastewater. Leersia hexandra Swartz is a metal-accumulating hygrophyte with great potential to remove heavy metal from water. In this study, two pilot-scale constructed wetlands planted with L. hexandra (CWL) were set up in greenhouse to treat electroplating wastewater containing Cr, Cu and Ni. The treatment performance of CWL under different hydraulic loading rates (HLR) and initial metal concentrations were also evaluated. The results showed that CWL significantly reduced the concentrations of Cr, Cu and Ni in wastewater by 84.4%, 97.1% and 94.3%, respectively. High HLR decreased the removal efficiencies of Cr, Cu and Ni; however, the heavy metal concentrations in effluent met Emission Standard of Pollutants for Electroplating in China (ESPE) at HLR less than 0.3 m3/m2 d. For the influent of 5 mg/L Cr, 10 mg/L Cu and 8 mg/L Ni, effluent concentrations were below maximum allowable concentrations in ESPE, indicating that the removal of Cr, Cu and Ni by CWL was feasible at considerably high influent metal concentrations. Mass balance showed that the primary sink for the retention of contaminants within the constructed wetland system was the sediment, which accounted for 59.5%, 83.5%, and 73.9% of the Cr, Cu and Ni, respectively. The data from the pilot wetlands support the view that CWL could be used to successfully remove Cr, Cu and Ni from electroplating wastewater.

  14. The quasicrystalline phase formation in Al-Cu-Cr alloys produced by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Sviridova, T.A.; Shevchukov, A.P.; Shelekhov, E.V. [National University of Science and Technology ' MISIS' , Moscow 119049 (Russian Federation); Diakonov, D.L. [Bardin Central Research Institute for the Iron and Steel Industry, Moscow 105005 (Russian Federation); Tcherdyntsev, V.V.; Kaloshkin, S.D. [National University of Science and Technology ' MISIS' , Moscow 119049 (Russian Federation)

    2011-06-15

    Research highlights: > Formation of decagonal quasicrystalline phase in Al-Cu-Cr alloys. > Obtained decagonal phase belongs to D{sub 3} family of decagonal quasicrystals. > Decagonal phase has 1.26 nm periodicity along 10-fold axis. > Alloys were produced by combination of mechanical alloying and subsequent annealing. > Phase composition of as-milled powders depending on annealing temperature. - Abstract: Almost single-phase decagonal quasicrystal with periodicity of 1.26 nm along 10-fold axis was produced in Al{sub 69}Cu{sub 21}Cr{sub 10} and Al{sub 72.5}Cu{sub 16.5}Cr{sub 11} alloys using combination of mechanical alloying (MA) and subsequent annealing. Phase transformations of as-milled powders depending on annealing temperature in the range of 200-800 deg. C are examined. Since the transformations can be explained based on kinetic and thermodynamic reasons it seems that applied technique (short preliminary MA followed by the annealing) permits to produce the equilibrium phases rather than metastable ones.

  15. Effects of Different Doping Ratio of Cu Doped CdS on QDSCs Performance

    Directory of Open Access Journals (Sweden)

    Xiaojun Zhu

    2015-01-01

    Full Text Available We use the successive ionic layer adsorption and reaction (SILAR method for the preparation of quantum dot sensitized solar cells, to improve the performance of solar cells by doping quantum dots. We tested the UV-Vis absorption spectrum of undoped CdS QDSCs and Cu doped CdS QDSCs with different doping ratios. The doping ratios of copper were 1 : 100, 1 : 500, and 1 : 1000, respectively. The experimental results show that, under the same SILAR cycle number, Cu doped CdS quantum dot sensitized solar cells have higher open circuit voltage, short circuit current density photoelectric conversion efficiency than undoped CdS quantum dots sensitized solar cells. Refinement of Cu doping ratio are 1 : 10, 1 : 100, 1 : 200, 1 : 500, and 1 : 1000. When the proportion of Cu and CdS is 1 : 10, all the parameters of the QDSCs reach the minimum value, and, with the decrease of the proportion, the short circuit current density, open circuit voltage, and the photoelectric conversion efficiency are all increased. When proportion is 1 : 500, all parameters reach the maximum values. While with further reduction of the doping ratio of Cu, the parameters of QDSCs have a decline tendency. The results showed that, in a certain range, the lower the doping ratio of Cu, the better the performance of quantum dot sensitized solar cell.

  16. Photocatalytic reduction of Cr(VI) on the novel hetero-system CuFe{sub 2}O{sub 4}/CdS

    Energy Technology Data Exchange (ETDEWEB)

    Nasrallah, N.; Kebir, M. [Laboratory of Engineering Reaction, Faculty of Engineering Mechanic and Engineering Processus (USTHB), BP 32, Algiers (Algeria); Koudri, Z. [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry (USTHB), BP 32, Algiers (Algeria); Trari, M., E-mail: solarchemistry@gmail.com [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry (USTHB), BP 32, Algiers (Algeria)

    2011-01-30

    The photocatalytic HCrO{sub 4}{sup -} reduction was investigated in air equilibrated solution using the spinel CuFe{sub 2}O{sub 4} nanoparticles as sensitizers. The oxide is p-type semi conductor, prepared from nitrates decomposition. The catalytic performance increases with decreasing pH and the concomitant oxidation of salicylic acid contributes significantly to the photoactivity through the charges separation of electron/hole pairs (C{sub 7}H{sub 6}O{sub 3} + 6 O{sub 2} + 4 h{sup +} + 3 H{sub 2}O {yields} 7 CO{sub 2} + 4 H{sub 3}O{sup +}). Evidence has been given to show the advantages of the hetero-system CuFe{sub 2}O{sub 4}/CdS in the chromate reduction. CuFe{sub 2}O{sub 4} acts as electrons pump and the electron transfer to chromate is mediated via CdS hexagonal variety (greenockite). A reduction of 60% occurs and the process is well described by a pseudo first order kinetic with a half life of {approx}2.8 h and a quantum yield of {approx}0.12% for an initial HCrO{sub 4}{sup -} concentration of 3 x 10{sup -4} M. An improvement up to 72% is obtained when the reaction occurs in a stirred reactor and no cadmium was detected after 6 h illumination. The results indicate a competitive effect with the water reduction. The hydrogen evolutions are found to be 0.236 and 0.960 cm{sup 3} mn{sup -1} g{sup -1} in presence and in absence of HCrO{sub 4}{sup -}, respectively.

  17. Modelling the leaching of Pb, Cd, As, and Cr from cementitious waste using PHREEQC

    International Nuclear Information System (INIS)

    Halim, Cheryl E.; Short, Stephen A.; Scott, Jason A.; Amal, Rose; Low, Gary

    2005-01-01

    A leaching model was developed using the United States Geological Survey public domain PHREEQC geochemical package to simulate the leaching of Pb, Cd, As, and Cr from cementitious wastes. The model utilises both kinetic terms and equilibrium thermodynamics of key compounds and provides information on leachate and precipitate speciation. The model was able to predict the leaching of Pb, Cd, As, and Cr from cement in the presence of both simple (0.1 and 0.6 M acetic acid) and complex municipal landfill leachates. Heavy metal complexation by the municipal landfill leachate was accounted for by the introduction of a monoprotic organic species into the model. The model indicated Pb and As were predominantly incorporated within the calcium silicate hydrate matrix while a greater portion of Cd was seen to exist as discrete particles in the cement pores and Cr (VI) existed mostly as free CrO 4 2- ions. Precipitation was found to be the dominant mechanism controlling heavy metal solubility with carbonate and silicate species governing the solubility of Pb and carbonate, silicate and hydroxide species governing the solubility of Cd. In the presence of acetic acid, at low pH values Pb and Cd acetate complexes were predominant whereas, at high pH values, hydroxide species dominated. At high pH values, the concentration of As in the leachate was governed by the solubility of Ca 3 (AsO 4 ) 2 with the presence of carbonate alkalinity competing with arsenate for Ca ions. In the presence of municipal landfill leachate, Pb and Cd organic complexes dominated the heavy metal species in solution. The reduction of As and Cr in municipal landfill leachate was crucial for determining aqueous speciation, with typical municipal landfill conditions providing the reduced forms of As and Cr

  18. Cumulation of Cu, Zn, Cd, and Mn in Plants of Gardno Lake

    Directory of Open Access Journals (Sweden)

    Trojanowski J.

    2013-04-01

    Full Text Available In the present paper there have been shown the results of research on yhe content of Zn, Cd, Cu, Mn and Pb in chosen plants of Lake Gardno.The biggest concentration of those metals has been observed in Potamogton natans and Elodea canadensis, on average Zn – 34.9, Pb -2.77, Cd – 0.62, Cu – 3.24 and Mn – 257.4 μg g-1. It has been found that the over-ground parts of the plants under analysis cumulate several times less of heavy metals than their roots. The determined enrichment factors enabled the researchers to state that Cu in the examined plants is of natural origin while Mn, Cd and Zn – of anthropogenic origin.

  19. Precipitation strengthened high strength, high conductivity Cu-Cr-Nb alloys produced by chill block melt spinning. Final Report Ph.D. Thesis

    Science.gov (United States)

    Ellis, David L.; Michal, Gary M.

    1989-01-01

    A series of Cu-based alloys containing 2 to 10 a/o Cr and 1 to 5 a/o Nb were produced by chill block melt spinning (CBMS). The melt spun ribbons were consolidated and hot rolled to sheet to produce a supersaturated Cu-Cr-Nb solid solution from which the high melting point intermetallic compound Cr2Nb could be precipitated to strengthen the Cu matrix. The results show that the materials possess electrical conductivities in excess of 90 percent that of pure Cu at 200 C and above. The strengths of the Cu-Cr-Nb alloys were much greater than Cu, Cu-0.6 Cr, NARloy-A, and NARloy-Z in the as-melt spun condition. The strengths of the consolidated materials were less than Cu-Cr and Cu-Cr-Zr below 500 C and 600 C respectively, but were significantly better above these temperatures. The strengths of the consolidated materials were greater than NARloy-Z, at all temperatures. The GLIDCOP possessed similar strength levels up to 750 C when the strength of the Cu-Cr-Nb alloys begins to degrade. The long term stability of the Cu-Cr-Nb alloys was measured by the microhardness of aged samples and the growth of precipitates. The microhardness measurements indicate that the alloys overage rapidly, but do not suffer much loss in strength between 10 and 100 hours which confirms the results of the electrical resistivity measurements taken during the aging of the alloys at 500 C. The loss in strength from peak strength levels is significant, but the strength remains exceptionally good. Transmission electron microscopy (TEM) of the as-melt spun samples revealed that Cr2Nb precipitates formed in the liquid Cu during the chill block melt spinning, indicating a very strong driving force for the formation of the precipitates. The TEM of the aged and consolidated materials indicates that the precipitates coarsen considerably, but remain in the submicron range.

  20. Hydroponic phytoremediation of Cd, Cr, Ni, As, and Fe: can Helianthus annuus hyperaccumulate multiple heavy metals?

    Science.gov (United States)

    January, Mary C; Cutright, Teresa J; Van Keulen, Harry; Wei, Robert

    2008-01-01

    Sundance sunflowers were subjected to contaminated solutions containing 3, 4, or 5 heavy metals, with and without EDTA. The sunflowers exhibited a metal uptake preference of Cd=Cr>Ni, Cr>Cd>Ni>As and Fe>As>Cd>Ni>Cr without EDTA and Cr>Cd>Ni, Fe>As>Cd>Cr>Ni with EDTA. As uptake was not affected by other metals, but it decreased Cd and Ni concentration in the stems. The presence of Fe improved the translocation of the other metals regardless of whether EDTA was present. In general, EDTA served as a hindrance to metal uptake. For the experiment with all five heavy metals, EDTA decreased Cd in the roots and stems from 2.11 to 1.36 and from 2.83 to 2.3 2mg g(-1) biomass, respectively. For the same conditions, Ni in the stems decreased from 1.98 to 0.94 mg g(-1) total metal uptake decreased from 14.95 mg to 13.89 mg, and total biomass decreased from 2.38 g to 1.99 g. These results showed an overall negative effect in addition of EDTA. However it is unknown whether the negative effect was due to toxicity posed by EDTA or the breaking of phytochelatin-metal bonds. The most important finding was the ability of Sundance sunflowers to achieve hyperaccumulator status for both As and Cd under all conditions studied. Ni hyperaccumulator status was only achieved in the presence of three metals without EDTA.

  1. On the Path to Optimizing the Al-Co-Cr-Cu-Fe-Ni-Ti High Entropy Alloy Family for High Temperature Applications

    Directory of Open Access Journals (Sweden)

    Anna M. Manzoni

    2016-03-01

    Full Text Available The most commonly investigated high entropy alloy, AlCoCrCuFeNi, has been chosen for optimization of its microstructural and mechanical properties by means of compositional changes and heat treatments. Among the different available optimization paths, the decrease of segregating element Cu, the increase of oxidation protective elements Al and Cr and the approach towards a γ-γ′ microstructure like in Ni-based superalloys have been probed and compared. Microscopical observations have been made for every optimization step. Vickers microhardness measurements and/or tensile/compression test have been carried out when the alloy was appropriate. Five derived alloys AlCoCrFeNi, Al23Co15Cr23Cu8Fe15Ni16, Al8Co17Cr17Cu8Fe17Ni33, Al8Co17Cr14Cu8Fe17Ni34.8Mo0.1Ti1W0.1 and Al10Co25Cr8Fe15Ni36Ti6 (all at.% have been compared to the original AlCoCrCuFeNi and the most promising one has been selected for further investigation.

  2. Adsorption of Cu(II) and Cr(VI) ions by chitosan: kinetics and ...

    African Journals Online (AJOL)

    The ability of chitosan as an adsorbent for Cu (II) and Cr (VI) ions in aqueous solution was studied. The experiments were done as batch processes. Equilibrium studies were done on both cross-linked and non-cross-linked chitosan for both metals. Cr (VI) adsorption behaviour could be described using the Langmuir ...

  3. Fast and direct analysis of Cr, Cd and Pb in brown sugar by GF AAS.

    Science.gov (United States)

    Dos Santos, Jeferson M; Quináia, Sueli P; Felsner, Maria L

    2018-09-15

    A simple and fast analytical method for the determination of Cr, Pb and Cd in brown sugar by GF AAS using slurry sampling was developed and in house validated for the first time. Analytical curves were prepared by external standardization for Cr, and by matrix simulation for Pb and Cd and they were linear. Low limits of quantification for Cr (32.8 ng g -1 ), Pb (49.3 ng g -1 ) and Cd (4.5 ng g -1 ) were found. Repeatability and intermediate precision estimates (brown sugar samples ranged from <32.8 to 160 ng g -1 for Cr, from <49.3 to 211.0 ng g -1 for Pb and from <4.5 to 7.0 ng g -1 for Cd and they may be assigned to anthropogenic activities and the adoption of inadequate practices of production and processing. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Creep and Oxidation Behavior of Modified CF8C-Plus with W, Cu, Ni, and Cr

    Science.gov (United States)

    Unocic, Kinga A.; Dryepondt, Sebastien; Yamamoto, Yukinori; Maziasz, Philip J.

    2016-04-01

    The microstructures of modified CF8C-Plus (Fe-19Cr-12Ni-0.4W-3.8Mn-0.2Mo-0.6Nb-0.5Si-0.9C) with W and Cu (CF8CPWCu) and CF8CPWCu enhanced with 21Cr + 15Ni or 22Cr + 17.5Ni were characterized in the as-cast condition and after creep testing. When imaged at lower magnifications, the as-cast microstructure was similar among all three alloys as they all contained a Nb-rich interdendritic phase and Mn-based inclusions. Transmission electron microscopy (TEM) analysis showed the presence of nanoscale Cu-rich nanoprecipitates distributed uniformly throughout the matrix of CF8CPWCu, whereas in CF8CPWCu22/17, Cu precipitates were found primarily at the grain boundaries. The presence of these nanoscale Cu-rich particles, in addition to W-rich Cr23C6, nanoscale Nb carbides, and Z-phase (Nb2Cr2N2), improved the creep strength of the CF8CPWCu steel. Modification of CF8CPWCu with Cr and Ni contents slightly decreased the creep strength but significantly improved the oxidation behavior at 1073 K (800 °C). In particular, the addition of 22Cr and 17.5Ni strongly enhanced the oxidation resistance of the stainless steel resulting in a 100 degrees or greater temperature improvement, and this composition provided the best balance between improving both mechanical properties and oxidation resistance.

  5. UV-Induced Anisotropy In CdBr2-CdBr2: Cu Nanostructures

    Directory of Open Access Journals (Sweden)

    El-Naggar A. M.

    2015-09-01

    Full Text Available We have found an occurrence of anisotropy in the nanostructure CdBr2-CdBr2: Cu nanocrystalline films. The film thickness was varied from 4 nm up to 80 nm. The films were prepared by successive deposition of the novel layers onto the basic nanocrystals. The detection of anisotropy was performed by occurrence of anisotropy in the polarized light at 633 nm He-Ne laser wavelength. The occurrence of anisotropy was substantially dependent on the film thickness and the photoinduced power density. Possible mechanisms of the observed phenomena are discussed.

  6. Synthesis and Characterization of High-Entropy Alloy AlFeCoNiCuCr by Laser Cladding

    Directory of Open Access Journals (Sweden)

    Xiaoyang Ye

    2011-01-01

    Full Text Available High-entropy alloys have been recently found to have novel microstructures and unique properties. In this study, a novel AlFeCoNiCuCr high-entropy alloy was prepared by laser cladding. The microstructure, chemical composition, and constituent phases of the synthesized alloy were characterized by SEM, EDS, XRD, and TEM, respectively. High-temperature hardness was also evaluated. Experimental results demonstrate that the AlFeCoNiCuCr clad layer is composed of only BCC and FCC phases. The clad layers exhibit higher hardness at higher Al atomic content. The AlFeCoNiCuCr clad layer exhibits increased hardness at temperature between 400–700°C.

  7. Thermoelectric properties of layered antiferromagnetic CuCrSe2

    International Nuclear Information System (INIS)

    Tewari, Girish C.; Tripathi, T.S.; Yamauchi, Hisao; Karppinen, Maarit

    2014-01-01

    Here we study thermoelectric and magnetic properties of CuCrSe 2 samples sintered at various temperatures. Structural analysis with XRD shows an order-disorder transition for Cr atoms when the sintering temperature is increased above 1273 K. Metal-like electrical resistivity and anomalously large Seebeck coefficient are found about room temperature. Analysis of electrical conductivity and Seebeck coefficient of the partially-disordered phase suggests hopping conduction of charge carriers. For both the ordered and disordered phases magnetic susceptibility follows Curie–Weiss temperature dependence at high temperatures above 150 K and shows an antiferromagnetic transition around 55 K. For the disordered phase, the effective magnetic moment is determined at 3.62 μ B ; this low value in comparison to the spin only value for Cr 3+ of 3.89 μ B indicates spin fluctuations in the paramagnetic state. The thermal conductivity in these phases is low and dominated by the lattice contribution. Values for the thermoelectric figure of merit (ZT) at room temperature are estimated to be 0.17 and 0.05 for the ordered and disordered phases, respectively. - Highlights: • Thermoelectric and magnetic properties of CuCrSe 2 samples are investigated. • The properties strongly depend on the degree of order of chromium atoms. • The degree of order is controlled by the sintering temperature. • Room-temperature figure of merit is estimated at 0.17 for the ordered phase. • For the disordered phase the figure of merit is lower

  8. Catalytic role of Cu(II) in the reduction of Cr(VI) by citric acid under an irradiation of simulated solar light.

    Science.gov (United States)

    Li, Ying; Chen, Cheng; Zhang, Jing; Lan, Yeqing

    2015-05-01

    The catalytic role of Cu(II) in the reduction of Cr(VI) by citric acid with simulated solar light was investigated. The results demonstrated that Cu(II) could significantly accelerate Cr(VI) reduction and the reaction obeyed to pseudo zero-order kinetics with respect to Cr(VI). The removal of Cr(VI) was related to the initial concentrations of Cu(II), citric acid, and the types of organic acids. The optimal removal of Cr(VI) was achieved at pH 4, and the rates of Cu(II) photocatalytic reduction of Cr(VI) by organic acids were in the order: tartaric acid (two α-OH groups, two -COOH groups)>citric acid (one α-OH group, three -COOH groups)>malic acid (one α-OH group, two -COOH groups)>lactic acid (one α-OH group, one -COOH group)≫succinic acid (two -COOH groups), suggesting that the number of α-OH was the key factor for the reaction, followed by the number of -COOH. The formation of Cu(II)-citric acid complex could generate Cu(I) and radicals through a pathway of metal-ligand-electron transfer, promoting the reduction of Cr(VI). This study is helpful to fully understanding the conversion of Cr(VI) in the existence of both organic acids and Cu(II) with solar light in aquatic environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Sandwich-like nano-system for simultaneous removal of Cr(VI) and Cd(II) from water and soil.

    Science.gov (United States)

    Wang, Dongfang; Zhang, Guilong; Dai, Zhangyu; Zhou, Linglin; Bian, Po; Zheng, Kang; Wu, Zhengyan; Cai, Dongqing

    2018-05-07

    In this work, a novel nano-system with sandwich-like structure was synthesized via face-to-face combination of two pieces of waste cotton fabrics (CFs) carrying ferrous sulfide (FeS) and carboxyl-functionalized ferroferric oxide (CFFM) respectively, and the obtained nano system was named as FeS/CFFM/CF. Therein, FeS has high reduction and adsorption capabilities for hexavalent chromium (Cr(VI)), CFFM possesses a high adsorption ability on cadmium ion (Cd(II)) through electrostatics attraction and chelation, and CF displays high immobilization ability for FeS and CFFM and adsorption performance on Cd(II). FeS/CFFM/CF could simultaneously remove Cr(VI) and Cd(II) from water, inhibit the uptake of Cr and Cd by fish and water spinach, ensuring the food safety. Besides, this technology could efficiently control migration of Cr(VI) and Cd(II) in sand-soil mixture, which was favorable to prevent their wide diffusion. Importantly, FeS/CFFM/CF possessed a high flexibility and could be conveniently produced with needed scale and shape, and easily separated from water and soil, displaying a promising approach to remediate Cr(VI)/Cd(II)-contaminated water and soil and a huge application potential.

  10. An experimental investigation of ionic transport properties in CuI-Ag2WO4 and CuI-Ag2CrO4 mixed systems

    International Nuclear Information System (INIS)

    Suthanthiraraj, S. Austin; Premchand, Y. Daniel

    2004-01-01

    The phenomenon of ionic transport in the case of two different mixed systems (CuI) (1-x) -(Ag 2 WO 4 ) x (0.15= (1-y) -(Ag 2 CrO 4 ) y (0.15= -3 Scm -1 for the composition (CuI) 0.45 -(Ag 2 WO 4 ) 0.55 and 1.1x10 -4 Scm -1 in the case of (CuI) 0.55 -(Ag 2 CrO 4 ) 0.45 at room temperature has been discussed in terms of the observed characteristics

  11. Electron transport in all-Heusler Co2CrSi/Cu2CrAl/Co2CrSi device, based on ab-initio NEGF calculations

    Science.gov (United States)

    Mikaeilzadeh, L.; Pirgholi, M.; Tavana, A.

    2018-05-01

    Based on the ab-initio non-equilibrium Green's function (NEGF) formalism based on the density functional theory (DFT), we have studied the electron transport in the all-Heusler device Co2CrSi/Cu2CrAl/Co2CrSi. Results show that the calculated transmission spectra is very sensitive to the structural parameters and the interface. Also, we obtain a range for the thickness of the spacer layer for which the MR effect is optimum. Calculations also show a perfect GMR effect in this device.

  12. Assessment of Cd, Cr and Pb Pollution in Sediment and Water of Gheshlagh River, Iran, in September 2013

    Directory of Open Access Journals (Sweden)

    Farshid Majnoni

    2015-03-01

    Full Text Available Background: This study aimed to evaluate the pollution levels of surface water with heavy metals including Pb, Cd and Cr in Gheshlagh River, western Iran. Methods: Water and sediment were sampled in five monitoring stations with three replicates in time along the river. The concentration of Cr, Pb and Cd in both water and sediment samples were measured with graphite furnace atomic absorption spectrometer (Australia, Varian 220. The Geoaccumulation Index and Pollution Load Index were employed to assess the pollution level of sediments with heavy metals. Results: The mean value of Cd, Cr, Pb in sediment samples were 0.69, 17.19 and 10.69 µgg-1 per dry weight, respectively. Water samples contained Cd, Cr and Pb concentration of 1.99, 1.45 and 12.92 µgL-1, respectively. The Geoaccumulation Index and Pollution Load Index indicates that the sediments were not polluted with Pb and Cr, and unpolluted to moderately contaminated with Cd in Gheshlagh River. Conclusion: This study concludes that the Gheshlagh River is threatened by heavy metals particularly Cd and Pb.

  13. Characterization of residues from thermal treatment of treated wood and extraction of Cu, Cr, As and Zn

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Pedersen, Anne Juul; Christensen, Iben Vernegren

    2005-01-01

    , that the charcoal contained a high concentration of Zn, probably from paint. Chemical extraction experiments in HNO were conducted with the charcoal and it was found that the order of extraction (in percentage) was Zn > Cu > As > Cr. A SEM/EDX investigation of the mixed ash from combustion showed the presence...... a matter to cope with when methods to avoid As emission are implemented: the residues with increased concentrations of Cu, Cr and As. In the present paper two different residues after thermal treatment are characterized: a mixed bottom and fly ash from combustion of CCA impregnated wood, and a charcoal...... form in a small layer on the surface of some matrix particles indicating condensation of volatile Cu species. Chemical extraction with inorganic acids showed the order of percentages mobilized as: As > Cu > Cr....

  14. The electrical conductivity of CuCrZr alloy after SPD processing

    International Nuclear Information System (INIS)

    Lipińska, M; Bazarnik, P; Lewandowska, M

    2014-01-01

    CuCrZr alloys exhibit very good relation between mechanical properties and electrical conductivity. However, for its use in some advanced applications improvement of mechanical strength while preserving high electrical conducting is required. Therefore, in this work a CuCrZr alloy was subjected to a series of thermo-mechanical treatments, including solution annealing and water quenching, SPD processing (using hydrostatic extrusion and ECAP) as well as aging in order to improve mechanical strength. The influence of these processing procedures on microstructure features and mechanical properties was determined by TEM observation and microhardness measurements, respectively. Electrical conductivity of the samples was measured by four-points method. The results have shown that it is possible to improve mechanical strength while preserving good electrical conductivity by a proper combination of SPD processing and heat treatment

  15. DMPD: CR3 (CD11b, CD18): a phagocyte and NK cell membrane receptor with multipleligand specificities and functions. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available ) (.html) (.csml) Show CR3 (CD11b, CD18): a phagocyte and NK cell membrane receptor with multipleligand specificities and function...d NK cell membrane receptor with multipleligand specificities and functions. Authors Ross GD, Vetvicka V. Pu...igand specificities and functions. Ross GD, Vetvicka V. Clin Exp Immunol. 1993 May;92(2):181-4. (.png) (.svg...8485905 CR3 (CD11b, CD18): a phagocyte and NK cell membrane receptor with multiplel

  16. Cu induced reactions on 110Cd-108Cd-106Cd, 109Ag-107Ag and 110Pd. New rhenium, osmium and iridium isotopes

    International Nuclear Information System (INIS)

    Cabot, C.; Della Negra, S.; Deprun, C.; Gauvin, H.; Le Beyec, Y.

    1978-01-01

    By 63 Cu induced reactions on 110 Cd, 108 Cd, 106 Cd, 109 Ag, 107 Ag and 110 Pd targets, new isotopes were searched in the Ir, Os, Re region. Cross bombardments and excitation function measurements were used to identify new α emitting isotopes. The α-decay measurements are compared to the Qα values obtained from different mass predictions

  17. Ferromagnetic-phase transition in the spinel-type CuCr2Te4

    International Nuclear Information System (INIS)

    Suzuyama, Takeshi; Awaka, Junji; Yamamoto, Hiroki; Ebisu, Shuji; Ito, Masakazu; Suzuki, Takashi; Nakama, Takao; Yagasaki, Katsuma; Nagata, Shoichi

    2006-01-01

    Ferromagnetic-phase transition in spinel-type CuCr 2 Te 4 has been clearly observed. CuCr 2 Te 4 is a telluride-spinel with the lattice constant a=11.134A, which has been synthesized successfully. The heat capacity exhibits a sharp peak due to the ferromagnetic-phase transition with the Curie temperature T C =326K. This value of T C corresponds exactly to that of the negative peak of dM/dT in low field of 1.0Oe. The magnetic susceptibility shows the Curie-Weiss behavior between 380 and 650K with the effective magnetic moment μ eff =4.14μ B /Cr-ion and the Weiss constant θ=+357K. The low temperature magnetization indicates the spin-wave excitations, where the existence of first term of Bloch T 3/2 law and the next T 5/2 term are verified experimentally. This spin-wave excitation is detected up to approximately 250K which is a fairly high temperature

  18. Controllable architecture of CdS and CuS by single-source precursor-mediated approach and their photocatalytic activity

    International Nuclear Information System (INIS)

    Sahoo, Ashish K.; Srivastava, Suneel K.

    2013-01-01

    The present work deals with the preparation of hexagonal CdS and CuS by solvothermal decomposition of the morpholine-4-carbdithioate (MCDT) complexes of Cd and Cu in a water/THF mixture at 140–180 °C for 24 h and characterization. Scanning electron microscopy, field emission scanning electron microscopy and high resolution transmission electron microscopy show that CdS exhibits a hierarchical star- and lotus flower-like morphology in the presence of disodium salt of ethylenediamine tetraaceticacid and sodium dodecyl benzene sulphonate as soft templates at 140 and 160 °C, respectively. However, Cu complex of MCDT forms CuS nanoparticles in the temperature range of 140–180 °C. On the contrary, CdS nanoparticles and CuS microparticles are formed in the absence of any template under the identical experimental conditions. Raman studies show the characteristic peak of CdS and CuS, irrespective of their size and morphology. Finally, CdS and CuS of varying morphology have successfully been used as catalysts in UV photocatalytic decomposition of methylene blue dye. These findings show that CdS lotus-like microflowers are more effective catalysts than hierarchical stars, though the latter is found to have better reusability.Graphical AbstractA simple soft template-assisted and single complex source precursor-mediated solvothermal synthesis of CdS and CuS with a diverse set of morphology has been reported. In addition, the morphology and application in photocatalysis are also discussed.

  19. Controllable architecture of CdS and CuS by single-source precursor-mediated approach and their photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, Ashish K.; Srivastava, Suneel K., E-mail: sunil111954@yahoo.co.uk [Indian Institute of Technology Kharagpur, Department of Chemistry (India)

    2013-04-15

    The present work deals with the preparation of hexagonal CdS and CuS by solvothermal decomposition of the morpholine-4-carbdithioate (MCDT) complexes of Cd and Cu in a water/THF mixture at 140-180 Degree-Sign C for 24 h and characterization. Scanning electron microscopy, field emission scanning electron microscopy and high resolution transmission electron microscopy show that CdS exhibits a hierarchical star- and lotus flower-like morphology in the presence of disodium salt of ethylenediamine tetraaceticacid and sodium dodecyl benzene sulphonate as soft templates at 140 and 160 Degree-Sign C, respectively. However, Cu complex of MCDT forms CuS nanoparticles in the temperature range of 140-180 Degree-Sign C. On the contrary, CdS nanoparticles and CuS microparticles are formed in the absence of any template under the identical experimental conditions. Raman studies show the characteristic peak of CdS and CuS, irrespective of their size and morphology. Finally, CdS and CuS of varying morphology have successfully been used as catalysts in UV photocatalytic decomposition of methylene blue dye. These findings show that CdS lotus-like microflowers are more effective catalysts than hierarchical stars, though the latter is found to have better reusability.Graphical AbstractA simple soft template-assisted and single complex source precursor-mediated solvothermal synthesis of CdS and CuS with a diverse set of morphology has been reported. In addition, the morphology and application in photocatalysis are also discussed.

  20. Behavior of tungsten coatings on CuCrZr heat sink with the different interlayers under high heat flux

    International Nuclear Information System (INIS)

    Chong, F.L.; Chen, J.L.; Li, J.G.; Zheng, X.B.; Hu, D.Y.; Ding, C.X.

    2007-01-01

    In recent years, tungsten coated CuCrZr by means of vacuum plasma spraying technology was studied at Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). Plasma spraying technology is a good integration way of armor material and heat sink, which overcomes the disadvantage of heavy weight and poor workability of tungsten, and offers the ability to coat large area, even complex shapes and in situ repair of damaged parts. But tungsten coated CuCrZr is a challenge due to the larger mismatch of their thermal expansion coefficients (CTE), which will induce the stress concentration on the joint interface of plasma facing component. In order to enhance the adhesion of W coating on CuCrZr substrate and avoid the thermal stress concentration, it is necessary to use a compliant interlayer. At present, titanium (Ti), nickel-chromium-aluminum (NiCrAl) alloys and W/Cu mixtures were chosen as the compliant layers to insert between W coating and CuCrZr substrate. The adhesion strength was performed at RT. The behaviors of W/Cu mock up under high heat flux were carried out by means of the electron beam facility with actively cooling. The results indicated that the mock-ups with the interlayer architectures can withstand the higher heat flux compared to that with the sharp interface, which exhibited the effect of interlayers on reducing the maximum stress and enhancing the properties of resistant heat flux load, though the maximum surface temperature increased due to inserting the interlayers. Among three interlayers, W/Cu interlayer was much better due to its good heat removal capability and flexible W/Cu ratios. Meanwhile, the behaviors of W/Cu mock-ups with the different interlayers were analyzed and optimized by ANSYS finite element code. (authors)

  1. Chemical reactions at CdS heterojunctions with CuInSe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Aquino, Angel; Rockett, Angus [Department of Materials Science and Engineering, University of Illinois, 1304 West Green Street, Urbana, Illinois 61801 (United States)

    2013-03-15

    The stability of the CdS/CuInSe{sub 2} (CIS) heterojunction is critical to understanding the projected lifetime of CIS devices and the effect of processing conditions on the nanoscale chemistry of the heterojunction. This article reports the results of annealing heterojunctions between CdS deposited by chemical bath deposition and single crystal and polycrystalline CIS films between 200 and 500 Degree-Sign C for 10 to 150 min. No atomic movement was observed by secondary ion mass spectrometry at temperatures of 300 Degree-Sign C and below. At 400 Degree-Sign C even for the shortest time studied, Cu and In were found throughout the region initially consisting of CdS only and Cd was found to have moved into the CIS. In the polycrystal, annealing at 500 Degree-Sign C resulted in movement of Cd throughout the CIS layer. No time dependence was observed in the 400 and 500 Degree-Sign C anneals indicating that a reaction had occurred forming a compound that was in thermodynamic equilibrium with the remaining CIS. Diffusion turns on rapidly between 300 and 400 Degree-Sign C, indicating a high activation energy for atomic movement ({approx}2.4 eV). The onset of diffusion is consistent with the onset of Cu diffusion in CIS.

  2. Growth control, structure, chemical state, and photoresponse of CuO-CdS core-shell heterostructure nanowires.

    Science.gov (United States)

    El Mel, A A; Buffière, M; Bouts, N; Gautron, E; Tessier, P Y; Henzler, K; Guttmann, P; Konstantinidis, S; Bittencourt, C; Snyders, R

    2013-07-05

    The growth of single-crystal CuO nanowires by thermal annealing of copper thin films in air is studied. We show that the density, length, and diameter of the nanowires can be controlled by tuning the morphology and structure of the copper thin films deposited by DC magnetron sputtering. After identifying the optimal conditions for the growth of CuO nanowires, chemical bath deposition is employed to coat the CuO nanowires with CdS in order to form p-n nanojunction arrays. As revealed by high-resolution TEM analysis, the thickness of the polycrystalline CdS shell increases when decreasing the diameter of the CuO core for a given time of CdS deposition. Near-edge x-ray absorption fine-structure spectroscopy combined with transmission x-ray microscopy allows the chemical analysis of isolated nanowires. The absence of modification in the spectra at the Cu L and O K edges after the deposition of CdS on the CuO nanowires indicates that neither Cd nor S diffuse into the CuO phase. We further demonstrate that the core-shell nanowires exhibit the I-V characteristic of a resistor instead of a diode. The electrical behavior of the device was found to be photosensitive, since increasing the incident light intensity induces an increase in the collected electrical current.

  3. Novel Preparation of Nano-Composite CuO-Cr2O3 Using Ctab-Template Method and Efficient for Hydrogenation of Biomass-Derived Furfural

    Science.gov (United States)

    Yan, Kai; Wu, Xu; An, Xia; Xie, Xianmei

    2013-02-01

    A simple route to fabricate nano-composite oxides CuO-Cr2O3 using hexadecyltrimethylammonium bromide (CTAB)-templated Cu-Cr hydrotalcite as the precursor is presented. This novel method is based on CTAB-templating effect for mesostructure directing and using the cheap metal nitrate, followed by removal of CTAB. It was indicated that the nano-composite CuO-Cr2O3 was formed during the removal of CTAB. X-ray diffraction (XRD) and transitional electronic microscopy (TEM) revealed nice nano-composite oxides CuO-Cr2O3 were formed with high crystallinity. N2 adsorption and desorption indicated that a high surface area of 170.5 m2/g with a pore size of 2.7 nm of the nano-composite CuO-Cr2O3 was facilely resulted. The as-synthesized nano-composite oxides CuO-Cr2O3 display good catalytic activities for hydrogenation of furfural to furfuryl alcohol, whereas 86% selectivity was achieved at 75% conversion of furfural.

  4. The efficiency of biosynthesis silica nanoparticles at removal of heavy metals Cr and Cu from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Sayadi

    2017-05-01

    Full Text Available Background and Aim: Nanotechnology considered as one of the main management strategy in reducing negative effects of water pollution, which leads to treating of water inexpensive and more effective. This study aimed to investigate the removal of Cr and Cu from aqueous solutions using nano-silicate which is synthesized by rice husk. Materials and Methods: In the present study, functionalized nano-silica with rice husk was fabricated and characterized by FT-IR، TEM, SEM and XRD. The effect of adsorbent dosage, initial concentration and equilibrium of chromium and copper and contact time in removal of mentioned heavy metals were investigated. Finally, the adsorption isotherms were analyzed. Results: The silica nanoparticles had nearly spherical morphology with a uniform size of about 80 nm. However, the obtained functionalized silica nanoparticles were spherical (about 90 nm in diameter. Results showed that optimum adsorption of Cr and Cu contaminant obtained at 100 minutes, while the optimum amount of adsorbent for Cr and Cu were 125 and 100 mg respectively. The optimal concentration of Cr and Cu was 2 mg/l. The correlation coefficients of adsorption isotherms of Cr (R2Langmuir =0.9946 and Cu (R2Langmuir =0.999 showed the good agreement between the adsorption data and Langmuir model. Conclusion: The study showed that the silica nanoparticles can be produced using agricultural waste as a inexpensive and environmentally friendly method and can be used to removing of contaminants from the aquatic environment.

  5. Ti{sub 3}CrCu{sub 4}: A possible 2-D ferromagnetic spin fluctuating system

    Energy Technology Data Exchange (ETDEWEB)

    Dhar, S. K.; Kulkarni, R.; Goyal, Neeraj [Department of Condensed Matter Physics & Materials Science, T.I.F.R., Homi Bhabha Road, Colaba, Mumbai, 400005 (India); Provino, A.; Manfrinetti, P. [Department of Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova (Italy); Paudyal, D. [The Ames Laboratory, US Department of Energy, Iowa State University, Ames, IA 50011-3020 (United States)

    2016-05-15

    Ti{sub 3}CrCu{sub 4} is a new ternary compound which crystallizes in the tetragonal Ti{sub 3}Pd{sub 5} structure type. The Cr atoms form square nets in the a-b plane (a = 3.124 Å) which are separated by an unusually large distance c = 11.228 Å along the tetragonal axis, thus forming a -2-D Cr-sublattice. The paramagnetic susceptibility is characterized by a low effective moment, μ{sub eff} = 1.1 μ{sub B}, a low paramagnetic Curie temperature θ{sub P} (below 7 K) and a temperature independent χ{sub 0} = 6.7 x 10{sup −4} emu/mol. The magnetization at 1.8 K increases rapidly with field nearly saturating to 0.2 μ{sub B}/f.u. The zero field heat capacity C/T shows an upturn below 7 K (∼190 mJ/mol K{sup 2} at ∼0.1K) which is suppressed in applied magnetic fields and interpreted as suggesting the presence of spin fluctuations. The resistivity at low temperatures shows non-Fermi liquid behavior. Overall, the experimental data thus reveal an unusual magnetic state in Ti{sub 3}CrCu{sub 4}, which likely has its origin in the layered nature of the Cr sub-lattice and ferromagnetic spin fluctuations. Density functional theoretical calculations reveal a sharp Cr density of states peak just above the Fermi level, indicating the propensity of Ti{sub 3}CrCu{sub 4} to become magnetic.

  6. Synchrotron-radiation photoemission study of CdS/CuInSe2 heterojunction formation

    International Nuclear Information System (INIS)

    Nelson, A.J.; Gebhard, S.; Rockett, A.; Colavita, E.; Engelhardt, M.; Hoechst, H.

    1990-01-01

    Synchrotron-radiation soft-x-ray photoemission spectroscopy was used to investigate the development of the electronic structure at the CdS/CuInSe 2 heterojunction interface. CdS overlayers were deposited in steps on single-crystal p- and n-type CuInSe 2 at 250 degree C. Results indicate that the CdS grows in registry with the substrate, initially in a two-dimensional growth mode followed by three-dimensional island growth as is corroborated by reflection high-energy electron-diffraction analysis. Photoemission measurements were acquired after each growth in order to observe changes in the valence-band electronic structure as well as changes in the In 4d, Se 3d, Cd 4d, and S 2p core lines. The results were used to correlate the interface chemistry with the electronic structure at these interfaces and to directly determine the CdS/CuInSe 2 heterojunction valence-band discontinuity and the consequent heterojunction band diagram. These results show that the Katnani-Margaritondo method is unreliable in determining offsets for heterojunctions where significant Fermi-level pinning may occur and where the local structure and chemistry of the interface depends strongly on the specific heterojunction

  7. Lattice parameter values and phase transitions for the Cu{sub 2}Cd{sub 1-z}Mn{sub z}SnSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe{sub z}SnSe{sub 4} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, E. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Quintero, M., E-mail: mquinter@ula.v [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Morocoima, M.; Quintero, E.; Grima, P.; Tovar, R.; Bocaranda, P. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Delgado, G.E.; Contreras, J.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Mora, A.E.; Briceno, J.M.; Avila Godoy, R.; Fernandez, J.L. [Laboratorio de Analisis Quimico y Estructural de Materiales, Departamento de Fisica, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Henao, J.A.; Macias, M.A. [Grupo de Investigacion en Quimica Estructural (GIQUE), Facultad de Ciencias, Escuela de Quimica, Universidad Industrial de Santander, Apartado aereo 678, Bucaramanga (Colombia)

    2009-11-03

    X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu{sub 2}Cd{sub 1-z}Mn{sub z}SnSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe{sub z}SnSe{sub 4} alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. For Cu{sub 2}Cd{sub 0.8}Fe{sub 0.2}SnSe{sub 4} as well as for Cu{sub 2}Cd{sub 0.2}Fe{sub 0.8}SnSe{sub 4} the crystal structures were refined using the Rietveld method. It was found that the internal distortion parameter sigma decreases as Cd is replaced by either Mn and/or Fe. For the Cu{sub 2}Cd{sub 1-z}Mn{sub z}SnSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe{sub z}SnSe{sub 4} alloy systems, only two single solid phase fields, the tetragonal stannite alpha(I4-bar2m) and the wurtz-stannite delta (Pmn2{sub 1}) structures were found to occur in the diagram. In addition to the tetragonal stannite alpha phase extra X-ray diffraction lines due to MnSe and/or FeSe{sub 2} were observed for as grown samples in the range 0.7 < z < 1.0. However, it was found that the amount of the extra phase decreased for the compressed samples.

  8. Influence of divalent metal on the decomposition products of hydrotalcite-like ternary systems M{sup II}-Al-Cr (M{sup II} = Zn, Cd)

    Energy Technology Data Exchange (ETDEWEB)

    Perez, M.R.; Crespo, I.; Ulibarri, M.A.; Barriga, C. [Departamento de Quimica Inorganica e Ingenieria Quimica, Campus de Rabanales, Universidad de Cordoba, Cordoba (Spain); Rives, V. [GIR-QUESCAT, Departamento de Quimica Inorganica, Universidad de Salamanca, Salamanca (Spain); Fernandez, J.M., E-mail: um1feroj@uco.es [Departamento de Quimica Inorganica e Ingenieria Quimica, Campus de Rabanales, Universidad de Cordoba, Cordoba (Spain)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer LDHs M{sup II}-Al-Cr (M = Zn, Cd) with Cr in the layer or interlayer have been prepared. Black-Right-Pointing-Pointer LDHs Zn-Al or Zn-Cr decompose by heating forming ZnO and ZnAl{sub 2}O{sub 4} or ZnO and ZnCr{sub 2}O{sub 4}. Black-Right-Pointing-Pointer LDHs Zn-Al-Cr give rise to the formation of ZnO and the mixed spinel ZnAl{sub 2-x}Cr{sub x}O{sub 4}. Black-Right-Pointing-Pointer LDH Cd-Al-Cr shows the formation of CdO, CdCr{sub 2-x}Al{sub x}O{sub 4}, and (Al, Cr){sub 2}O{sub 3} mixed oxide. Black-Right-Pointing-Pointer Calcination of the CdAl-CrO{sub 4} give rise to (Al, Cr){sub 2}O{sub 3} as the majority phase. - Abstract: Layered double hydroxides (LDHs) containing M{sup II}, Al{sup III}, and Cr{sup III} in the brucite-like layers (M = Cd, Zn) with different starting Al/Cr molar ratios and nitrate/carbonate as the interlayer anion have been prepared following the coprecipitation method at a constant pH: Zn{sup II}-Al{sup III}-Cr{sup III}-CO{sub 3}{sup 2-} at pH = 10, and Cd{sup II}-Al{sup III}-Cr{sup III}-NO{sub 3}{sup -} at pH = 8. Two additional M{sup II},Al{sup III}-LDH samples (M = Cd, Zn) with chromate ions (CrO{sub 4}{sup 2-}) in the interlayer have been prepared by ionic exchange at pH = 9 and 8, respectively, starting from M{sup II}-Al{sup III}-NO{sub 3}{sup -}. The samples have been characterised by absorption atomic spectrometry, powder X-ray diffraction (PXRD), FT-IR spectroscopy and transmission electron microscopy (TEM). Their thermal stability has been assessed by DTA-TG and mass spectrometric analysis of the evolved gases. The PXRD patterns of the solids calcined at 800 Degree-Sign C show diffraction lines corresponding to ZnO and ZnAl{sub 2-x}Cr{sub x}O{sub 4} for the Zn-containing samples, and diffraction lines attributed to CdO and CdCr{sub 2}O{sub 4} and (Al,Cr){sub 2}O{sub 3} for the Cd-containing ones. Additionally a minority oxide, Cd{sub 2}CrO{sub 5}, is observed to Cd{sup II}-Al{sup III

  9. Optimization of the diffusion bonding parameters for SS316L/CuCrZr with and without Nickel interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Singh, K.P., E-mail: kpsingh@ipr.res.in; Patel, Alpesh; Bhope, Kedar; Khirwadkar, S.S.; Mehta, Mayur

    2016-11-15

    Highlights: • Optimization of diffusion bonding parameters for dissimilar materials SS316L with CuCrZr is proposed with and without Nickel interlayer. • Ultrasonic testing on diffusion bonded samples provides the overall information/signatures about well-bonded and de-bonded samples. • Microstructural examination confirms the diffusion of Nickel into parent materials. • Mechanical characterization such as hardness measurement and shear measurement supports the results. - Abstract: Divertor & Firstwall module of ITER like tokamak has several joints of dissimilar materials such as Tungsten (W) to Copper (Cu), Cu to CuCrZr (heat sink material) and CuCrZr to Stainless Steel (SS) materials. These Plasma Facing Components (PFC) are made of multi-layered joints, which are to be exposed to the harsh environment of Plasma with the expected heat flux of 5–10 MW/m{sup 2}. The joining of SS316L material to CuCrZr material is proposed in this paper. As SS316L/CuCrZr being dissimilar materials, direct joining of these materials is a problem, which needs a suitable fabrication process. The joining of SS316L with heat sink material (CuCrZr) requires the good thermal transfer and sound in structural joint. Diffusion bonding technique has been adopted as a process for joining of these two dissimilar materials. The primary objective of the joining study is to obtain the best diffusion bonding parameters for ITER like tokamak application. Thermo-mechanical simulator machine (Gleeble 3800) is used to perform diffusion bonding experiments at different temperatures 650 °C, 850 °C, 900 °C, 950 °C & 1000 °C, different uniaxial pressure varying from 5 MPa to 15 MPa and with the holding time of 15 min & 30 min, using pure nickel interlayer. The diffusion bonded samples have undergone Non-destructive testing (NDT) particularly the ultrasonic examination using immersion probe technique, microstructural examination by the High Resolution (HR) electron microscopy (SEM), Energy

  10. Optimization of the diffusion bonding parameters for SS316L/CuCrZr with and without Nickel interlayer

    International Nuclear Information System (INIS)

    Singh, K.P.; Patel, Alpesh; Bhope, Kedar; Khirwadkar, S.S.; Mehta, Mayur

    2016-01-01

    Highlights: • Optimization of diffusion bonding parameters for dissimilar materials SS316L with CuCrZr is proposed with and without Nickel interlayer. • Ultrasonic testing on diffusion bonded samples provides the overall information/signatures about well-bonded and de-bonded samples. • Microstructural examination confirms the diffusion of Nickel into parent materials. • Mechanical characterization such as hardness measurement and shear measurement supports the results. - Abstract: Divertor & Firstwall module of ITER like tokamak has several joints of dissimilar materials such as Tungsten (W) to Copper (Cu), Cu to CuCrZr (heat sink material) and CuCrZr to Stainless Steel (SS) materials. These Plasma Facing Components (PFC) are made of multi-layered joints, which are to be exposed to the harsh environment of Plasma with the expected heat flux of 5–10 MW/m 2 . The joining of SS316L material to CuCrZr material is proposed in this paper. As SS316L/CuCrZr being dissimilar materials, direct joining of these materials is a problem, which needs a suitable fabrication process. The joining of SS316L with heat sink material (CuCrZr) requires the good thermal transfer and sound in structural joint. Diffusion bonding technique has been adopted as a process for joining of these two dissimilar materials. The primary objective of the joining study is to obtain the best diffusion bonding parameters for ITER like tokamak application. Thermo-mechanical simulator machine (Gleeble 3800) is used to perform diffusion bonding experiments at different temperatures 650 °C, 850 °C, 900 °C, 950 °C & 1000 °C, different uniaxial pressure varying from 5 MPa to 15 MPa and with the holding time of 15 min & 30 min, using pure nickel interlayer. The diffusion bonded samples have undergone Non-destructive testing (NDT) particularly the ultrasonic examination using immersion probe technique, microstructural examination by the High Resolution (HR) electron microscopy (SEM), Energy

  11. The role of complement receptors type 1 (CR1, CD35) and 2 (CR2, CD21) in promoting C3 fragment deposition and membrane attack complex formation on normal peripheral human B cells

    DEFF Research Database (Denmark)

    Nielsen, Claus Henrik; Pedersen, Morten Løbner; Marquart, Hanne Vibeke Hansen

    2002-01-01

    Normal human B lymphocytes are known to activate the alternative pathway (AP) of complement, leading to C3-fragment deposition and membrane attack complex (MAC) formation. The process is mediated via complement receptor type 2 (CR2, CD21), with complement receptor type 1 (CR1, CD35) playing...... a subsidiary role. In this study, we examine the relative contributions of CR1 and CR2 to the deposition of C3 fragments and MAC on B lymphocytes under circumstances where all complement pathways are operational. C3-fragment deposition and MAC formation were assessed on human peripheral B lymphocytes...... in the presence of 30% autologous serum. Blocking the CR2 ligand-binding site with monoclonal antibody (mAb) FE8 resulted in significant reduction (37.9+/-11.9%) in C3-fragment deposition, whereas MAC formation was only marginally affected (12.1+/-22.2% reduction). Blocking the CR1 binding-site resulted...

  12. Chemical speciation of Pb, Ni Cr, Cu, Co and V in two natural soils and in an antropic agricultural soil contaminated by irrigation with the polluted Rio Bogota waters in its High Basin

    International Nuclear Information System (INIS)

    Matamoros, Adriana; Vargas, O; Mejia, L

    1999-01-01

    Traditional and continuous irrigation with the highly polluted waters of Rio Bogota in its upper basin has induced in soils, grasses and crops grown next to the river, a gradually increasing accumulation of highly toxic elements like Pb, Ni, Cr, Cu, Cd, Co, V and some others, which represents a real and very high risk for public health whenever grasses and edible crops growing on them absorb these elements above critical or permissible limits. To evaluate the magnitude of this problem three different soils of the Sabana were subjected to the chemical speciation procedure proposed by Tessier (1979) in order to determine: 1) the total content of essential and/or structural elements like Al, Fe, Ca, K, P, Mn and Ti, and the trace elements Pb, Ni, Cr, Cu, Cd, Co and V accumulated through time in the soils; 2) the relative proportion on which each one of them are linked to the different components or fractions of soils (ex. exchangeable, CO 3 , Fe/Mn oxides, O.M. and sulfides, and residual fraction) and 3) the bioavailability or amount of each that could be really absorbed by plants or able to go down to the underground water. Results showed in general for all soils normal values for the essential and/or structural elements and high to very high levels of Pb, Ni, Cu, Cd, Cr, Co y V, higher in Jardines de Colombia and Las Parcelas farms soils than in el Recreo farm soils. This situation is aggravated by the relatively high mobility and high concentration and bioavailability of some of these elements, which increase the risk for public health and the possibility of its migration down to the underground waters

  13. Behaviors of heavy metals (Cd, Cu, Ni, Pb and Zn) in soil amended with composts.

    Science.gov (United States)

    Gusiatin, Zygmunt Mariusz; Kulikowska, Dorota

    2016-09-01

    This study investigated how amendment with sewage sludge compost of different maturation times (3, 6, 12 months) affected metal (Cd, Cu, Ni, Pb, Zn) bioavailability, fractionation and redistribution in highly contaminated sandy clay soil. Metal transformations during long-term soil stabilization (35 months) were determined. In the contaminated soil, Cd, Ni and Zn were predominately in the exchangeable and reducible fractions, Pb in the reducible fraction and Cu in the reducible, exchangeable and oxidizable fractions. All composts decreased the bioavailability of Cd, Ni and Zn for up to 24 months, which indicates that cyclic amendment with compost is necessary. The bioavailability of Pb and Cu was not affected by compost amendment. Based on the reduced partition index (IR), metal stability in amended soil after 35 months of stabilization was in the following order: Cu > Ni = Pb > Zn > Cd. All composts were more effective in decreasing Cd, Ni and Zn bioavailability than in redistributing the metals, and increasing Cu redistribution more than that of Pb. Thus, sewage sludge compost of as little as 3 months maturation can be used for cyclic amendment of multi-metal-contaminated soil.

  14. Effect of Ti content on structure and properties of Al2CrFeNiCoCuTix high-entropy alloy coatings

    International Nuclear Information System (INIS)

    Qiu, X.W.; Zhang, Y.P.; Liu, C.G.

    2014-01-01

    Highlights: • Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. • Al 2 CrFeNiCoCuTi x coatings show excellent corrosion resistance and wear resistance. • Al 2 CrFeNiCoCuTi x coatings play a good protective effect on Q235 steel. • Ti element promotes the formation of a BCC structure in a certain extent. -- Abstract: The Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. The structure, hardness, corrosion resistance, wear resistance and magnetic property were studied by metallurgical microscope, scanning electron microscopy with spectroscopy (SEM/EDS), X-ray diffraction, micro/Vickers hardness tester, electrochemical workstation tribometer and multi-physical tester. The result shows that, Al 2 CrFeNiCoCuTi x high-entropy alloy samples consist of the cladding zone, bounding zone, heat affected zone and substrate zone. The bonding between the cladding layer and the substrate of a good combination; the cladding zone is composed mainly of equiaxed grains and columnar crystal; the phase structure of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings simple for FCC, BCC and Laves phase due to high-entropy affect. Ti element promotes the formation of a BCC structure in a certain extent. Compared with Q235 steel, the free-corrosion current density of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings is reduced by 1–2 orders of magnitude, the free-corrosion potential is more “positive”. With the increasing of Ti content, the corrosion resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings enhanced in 0.5 mol/L HNO 3 solution. Compared with Q235 steel, the relative wear resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings has improved greatly; both the hardness and plasticity are affecting wear resistance. Magnetization loop shows that, Ti 0.0 high-entropy alloy is a kind of soft magnetic materials

  15. Stress relaxation study of water atomized Cu-Cr-Zr powder alloys consolidated by inverse warm extrusion

    International Nuclear Information System (INIS)

    Poblano-Salas, C.A.; Barceinas-Sanchez, J.D.O.

    2009-01-01

    Stress relaxation testing in compression at high temperature was performed on Cu-Cr-Zr alloys produced by consolidation of water atomized powders. Precipitation and recrystallization were monitored during stress relaxation experiments carried out at an ageing temperature of 723 K. Pre-straining imposed to the Cu-Cr-Zr samples prior to stress relaxation testing resulted in reduced hardness compared to that reported for conventionally-aged alloys; it also resulted in shorter times for achieving maximum strengthening on ageing.

  16. Is vetiver grass of interest for the remediation of Cu and Cd to protect marketing gardens in Burkina Faso?

    Science.gov (United States)

    Ondo Zue Abaga, Norbert; Dousset, Sylvie; Mbengue, Saliou; Munier-Lamy, Colette

    2014-10-01

    In Burkina-Faso, urban vegetable agriculture is often characterized by urban solid waste fertilizer inputs containing heavy metals such as Cu and Cd. Thus, the relevance of surrounding urban vegetable plots with vetiver hedges to reduce environmental pollution by Cu and Cd was investigated by adsorption studies and pot experiments. Vetiver biomass, its metal contents and, its total and MgCl2 extractable soil metals were monitored over 6months in the presence of a mixture of metal at two concentrations: 2-10 and 100-500mgkg(-1), for Cd and Cu, respectively. The Freundlich adsorption coefficient (Kf) values increased after vetiver growth and were significantly higher for vertisol than for lixisol. After 6months, the vetiver that was grown on lixisol accumulated more metal, increasing up to 4635mgkg(-1) for Cu and to 21.8mgkg(-1) for Cd, than did the vetiver that was grown on vertisol, increasing up to 1534mgkg(-1) for Cu and to 7.2mgkg(-1) for Cd. The metal bioconcentration factor, which was significantly higher for Cd, increased with the applied concentration and ranged from 1.6 to 14 for Cu and from 2.3 to 22 for Cd. Additionally, the translocation factors were higher for Cd (0.38-7.3) than for Cu (0.07-2.6), and the translocation was easiest from lixisol than from vertisol. Thus our results demonstrate the ability of vetiver for Cu and Cd phytoremediation in Burkina Faso soils. Nevertheless, these results should be confirmed across the field to advocate the establishment of vetiver hedges. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. PROFIL LOGAM BERAT Cd, Cr (VI DAN Pb PADA LOKASI BERBEDA DI PROVINSI LAMPUNG SERTA BIOAKUMULASINYA PADA TANAMAN PANGAN

    Directory of Open Access Journals (Sweden)

    Hening Widowati

    2015-11-01

    Full Text Available The heavy metal profile analysis of Cd, Cr(VI and Pb in the different location in Lampung Province and their bioaccumulation to crops has been conducted. The aims were finding out the difference of metal accumulation in the different pollutant area and determining how it happened to the vegetables surrounding, which were kangkoong and spinach. The research methods were purposive sampling in the different location in Lampung Province, namely 1 highlands, 2 paddy fields, 3 road sides and 4industrial areas. Based on the results, it is found that the highest metal concentration of Cd, Cr(VI and Pb are in the industrial area. Commonly, the value of BCFo-w (0,12-2,00 is higher than BCF¬o-s (0,01-0,18 which shows that there is low metal accumulation of Cd, Cr(VI and Pb in kangkoong and spinach. Furthermore, the BCF value of Cd and Cr(VI are higher compared to Pb.  Keywords: Logam berat, Cd, Cr(VI, Pb,bioakumulasi.

  18. Linking biosensor responses to Cd, Cu and Zn partitioning in soils

    International Nuclear Information System (INIS)

    Dawson, J.J.C.; Campbell, C.D.; Towers, W.; Cameron, C.M.; Paton, G.I.

    2006-01-01

    Soils bind heavy metals according to fundamental physico-chemical parameters. Bioassays, using bacterial biosensors, were performed in pore waters extracted from 19 contrasting soils individually amended with Cd, Cu and Zn concentrations related to the EU Sewage Sludge Directive. The biosensors were responsive to pore waters extracted from Zn amended soils but less so to those of Cu and showed no toxicity to pore water Cd at these environmentally relevant amended concentrations. Across the range of soils, the solid-solution heavy metal partitioning coefficient (K d ) decreased (p d values. Gompertz functions of Cu and Zn, K d values against luminescence explained the relationship between heavy metals and biosensors. Consequently, biosensors provide a link between biologically defined hazard assessments of metals and standard soil-metal physico-chemical parameters for determining critical metal loadings in soils. - Biosensors link biological hazard assessments of metals in soils with physico-chemical partitioning

  19. Electrochemiluminescence assay of Cu2+ by using one-step electrodeposition synthesized CdS/ZnS quantum dots.

    Science.gov (United States)

    Zhao, Guanhui; Li, Xiaojian; Zhao, Yongbei; Li, Yueyuan; Cao, Wei; Wei, Qin

    2017-08-21

    A sensitive and selective method was proposed to detect Cu 2+ based on the electrochemiluminescence quenching of CdS/ZnS quantum dots (QDs). Herein, CdS/ZnS QDs were one-step electrodeposited directly on a gold electrode from an electrolyte (containing Cd(NO 3 ) 2 , Zn(NO 3 ) 2 , EDTA and Na 2 S 2 O 3 ) by cycling the potential from 0 to -1.8 V. The prepared CdS/ZnS QDs exhibited excellent solubility and strong and stable cathodic ECL activity. Meanwhile, Nafion was used to immobilize CdS/ZnS QDs. The quenching effect of Cu 2+ on the cathodic ECL of CdS/ZnS QDs was found to be selective and concentration dependent. The linear range for Cu 2+ detection was from 2.5 nM to 200 nM with a detection limit of 0.95 nM. Furthermore, the designed method for the detection of Cu 2+ can provide a reference for the detection of other heavy metal ions.

  20. Effect of Post Treatment For Cu-Cr Source/Drain Electrodes on a-IGZO TFTs.

    Science.gov (United States)

    Hu, Shiben; Fang, Zhiqiang; Ning, Honglong; Tao, Ruiqiang; Liu, Xianzhe; Zeng, Yong; Yao, Rihui; Huang, Fuxiang; Li, Zhengcao; Xu, Miao; Wang, Lei; Lan, Linfeng; Peng, Junbiao

    2016-07-27

    We report a high-performance amorphous Indium-Gallium-Zinc-Oxide (a-IGZO) thin-film transistor (TFT) with new copper-chromium (Cu-Cr) alloy source/drain electrodes. The TFT shows a high mobility of 39.4 cm 2 ·V - 1 ·s - 1 a turn-on voltage of -0.8 V and a low subthreshold swing of 0.47 V/decade. Cu diffusion is suppressed because pre-annealing can protect a-IGZO from damage during the electrode sputtering and reduce the copper diffusion paths by making film denser. Due to the interaction of Cr with a-IGZO, the carrier concentration of a-IGZO, which is responsible for high mobility, rises.

  1. SXPS investigation of the Cd partial electrolyte treatment of CuInSe2 absorbers

    International Nuclear Information System (INIS)

    Hunger, R.; Schulmeyer, T.; Klein, A.; Jaegermann, W.; Lebedev, M.V.; Sakurai, K.; Niki, S.

    2005-01-01

    The chemical modification of polycrystalline CuInSe 2 absorber surfaces by the so-called Cd partial electrolyte (PE) treatment was studied by synchrotron X-ray photoelectron spectroscopy (SXPS). The Cd PE treatment was found to remove surface indium oxides and hydroxides and segregated sodium compounds. A hydroxide-terminated CdSe surface layer of one monolayer thickness is formed by the partial electrolyte treatment. The reaction mechanism is discussed as substrate site-controlled exchange reaction, where surface indium is removed and replaced by cadmium. Electronically, the Cd PE treated surface is inverted and exhibits a surface barrier which is by 0.2 eV higher than a comparable structure that was prepared by the vacuum deposition of one monolayer of CdS onto clean CuInSe 2

  2. Influence of Cu-Cr substitution on structural, morphological, electrical and magnetic properties of magnesium ferrite

    Science.gov (United States)

    Yonatan Mulushoa, S.; Murali, N.; Tulu Wegayehu, M.; Margarette, S. J.; Samatha, K.

    2018-03-01

    Cu-Cr substituted magnesium ferrite materials (Mg1 - xCuxCrxFe21 - xO4 with x = 0.0-0.7) have been synthesized by the solid state reaction method. XRD analysis revealed the prepared samples are cubic spinel with single phase face centered cubic. A significant decrease of ∼41.15 nm in particle size is noted in response to the increase in Cu-Cr substitution level. The room temperature resistivity increases gradually from 0.553 × 105 Ω cm (x = 0.0) to 0.105 × 108 Ω cm (x = 0.7). Temperature dependent DC-electrical resistivity of all the samples, exhibits semiconductor like behavior. Cu-Cr doped materials can be suitable to limit the eddy current losses. VSM result shows pure and doped magnesium ferrite particles show soft ferrimagnetic nature at room temperature. The saturation magnetization of the samples decreases initially from 34.5214 emu/g for x = 0.0 to 18.98 emu/g (x = 0.7). Saturation magnetization, remanence and coercivity are decreased with doping, which may be due to the increase in grain size.

  3. Determination of Cr, Cd, Sn, and Pb in Selected Herbal Products Available in Philippine Markets

    Directory of Open Access Journals (Sweden)

    Joan S. De Vera

    2017-12-01

    Full Text Available The growing popularity of herbal products in the Philippines makes it imperative to monitor and ensure safety of consumers from metal contaminants. In this study, trace concentrations of Cr, Cd, Sn, and Pb in herbal products were simultaneously measured using a microwaveassisted digestion as sample pre-treatment and inductively coupled plasma mass spectrometry (ICP-MS for elemental detection. Using the optimized method, recoveries of ERM CD281, the primary cer t i f ied reference material (CRM used, were found to be between 80-89%, and the method detection limits (MDL for Cr, Cd, Sn, and Pb were 0.15, 0.07, 0.3, and 0.14 μg/L, respectively. The linear ranges for Cr and other elements (Cd, Sn, and Pb were 0.01-500 and 0.01-50 μg/L, respectively. All correlation coeff icients were 0.9999 or better. Most of the products tested had measurable trace metal concentrations, which were below the suggested maximum limits in herbal products. However, one product derived from mangosteen exceeded the limit for Cd (0.42 mg/kg. Subsequent analysis of metal content in tea infusions showed that only a small fraction of metals may leach out, suggesting that consumption of tea infusions pose lesser risks. The order of abundance of metals found in herbal products was Cr>Pb>Cd>Sn. The variability of metal concentrations in herbal products underlines the fact that many plant ingredients are susceptible to contamination, and quality control during processing must be improved to minimize the possibility of contamination. The results of this study suggest that vigilant monitoring of herbal products is imperative to avoid exposure to trace metal contamination.

  4. Determination of Proton Relaxivities of Mn(II, Cu(II and Cr(III added to Solutions of Serum Proteins

    Directory of Open Access Journals (Sweden)

    Ali Yilmaz

    2009-04-01

    Full Text Available Relaxometric studies are still of scientific interest due to their use in medicine and biology. In this study, proton T1 and T2 relaxivities of Mn(II, Cu(II and Cr(III in water were determined in the presence and absence of various proteins (albumin, α-globulin, γ-globulin, lysozyme, fibrinogen. The 1/T1 and 1/T2 in all solutions are linearly proportional to the concentration of the paramagnetic ions. Mn(II has the great influence to alter relaxations in all protein solutions, while Cu(II and Cr(III have a poor influence on the relaxations. In addition, Mn(II and Cu(II are bound to each protein, but Cr(III is not bound to any protein.

  5. Sub-micron-sized delafossite CuCrO2 with different morphologies ...

    Indian Academy of Sciences (India)

    Currently, copper chromium oxide crystallizing in delafossite structure attracts huge research interest due to its versatile applications arising from its layered structure. In this work, delafossite CuCrO 2 was synthesized by sol–gel method from their respective hydrated nitrate salts with citric acid as a chelating agent.

  6. The influence of metal speciation in combustion waste on the efficiency of Cu, Pb, Zn, Cd, Ni and Cr bioleaching in a mixed culture of sulfur-oxidizing and biosurfactant-producing bacteria.

    Science.gov (United States)

    Karwowska, Ewa; Wojtkowska, Małgorzata; Andrzejewska, Dorota

    2015-12-15

    Metal leachability from ash and combustion slag is related to the physico-chemical properties, including their speciation in the waste. Metals speciation is an important factor that influences the efficiency of metal bioleaching from combustion wastes in a mixed culture of acidophilic and biosurfactant-producing bacteria. It was observed that individual metals tended to occur in different fractions, which reflects their susceptibility to bioleaching. Cr and Ni were readily removed from wastes when present with a high fraction bound to carbonates. Cd and Pb where not effectively bioleached when present in high amounts in a fraction bound to organic matter. The best bioleaching results were obtained for power plant slag, which had a high metal content in the exchangeable, bound to carbonates and bound to Fe and Mg oxides fractions- the metal recovery percentage for Zn, Cu and Ni from this waste exceeded 90%. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Determination of Cd, Cr and Pb in phosphate fertilizers by laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Lidiane Cristina; Gustinelli Arantes de Carvalho, Gabriel [NAPTISA Research Support Center “Technology and Innovation for a Sustainable Agriculture”, Center for Nuclear Energy in Agriculture, University of São Paulo, Av. Centenário 303, 13416-000, Piracicaba SP (Brazil); Santos, Dario [Federal University of São Paulo, R. Prof. Artur Riedel 275, 09972-270, Diadema SP (Brazil); Krug, Francisco José, E-mail: fjkrug@cena.usp.br [NAPTISA Research Support Center “Technology and Innovation for a Sustainable Agriculture”, Center for Nuclear Energy in Agriculture, University of São Paulo, Av. Centenário 303, 13416-000, Piracicaba SP (Brazil)

    2014-07-01

    A validated method for quantitative determination of Cd, Cr, and Pb in phosphate fertilizers by laser-induced breakdown spectroscopy (LIBS) is presented. Laboratory samples were comminuted and homogenized by cryogenic or planetary ball milling, pressed into pellets and analyzed by LIBS. The experimental setup was designed by using a Q-switched Nd:YAG at 1064 nm with 10 Hz repetition rate, and the intensity signals from Cd II 214.441 nm, Cr II 267.716 nm and Pb II 220.353 nm emission lines were measured by using a spectrometer furnished with an intensified charge-coupled device. LIBS parameters (laser fluence, lens-to-sample distance, delay time, integration time gate, number of sites and number of laser pulses per site) were chosen after univariate experiments with a pellet of NIST SRM 695 (Trace Elements in Multi-Nutrient Fertilizer). Calibration and validation were carried out with 30 fertilizer samples from single superphosphate, triple superphosphate, monoammonium phosphate, and NPK mixtures. Good results were obtained by using 30 pulses of 50 J cm{sup −2} (750 μm spot size), 2.0 μs delay time and 5.0 μs integration time gate. No significant differences between Cd, Cr, and Pb mass fractions determined by the proposed LIBS method and by ICP OES after microwave-assisted acid digestion (AOAC 2006.03 Official Method) were found at 95% confidence level. The limits of detection of 1 mg kg{sup −1} Cd, 2 mg kg{sup −1} Cr and 15 mg kg{sup −1} Pb and the precision (coefficients of variation of results ranging from 2% to 15%) indicate that the proposed LIBS method can be recommended for the determination of these analytes in phosphate fertilizers. - Highlights: • First LIBS application for quantitative Cd, Cr and Pb determination in fertilizers. • LIBS method was validated for analysis of phosphate fertilizers pressed pellets. • LIBS sample throughput is remarkably better than already existing methods.

  8. Behaviour of nonlinear dynamic susceptibility above the Curie point in the cubic ferromagnetics CdCr2S4 and CdCr2Se4

    International Nuclear Information System (INIS)

    Luzyanin, I.D.; Khavronin, V.P.

    1984-01-01

    Results are presented of an experimental investigation of the behaviour of the nonlinear dynamic susceptibility in the phase transition region the cubic, weakly anisotropic ferromagnetics CdCr 2 S 4 and CdCr 2 Se 4 . It is shown that above the Curie point Tsub(C) two temperature regions, a scaling and anomalous, can be distinguished which involve critical phenomena of different nature. In the scaling region which corresponds to 4πchisub(0)) < or approximately 25, the behaviour found for the linear and nonlinear susceptibilities are in satisfactory agreement with the theoretical predictions based on similarity considerations. The anomalous region is directly adjacent to Tsub(C). In this region phenomena are observed which are not consistent with current concepts regarding the nature of second order phase transitions e.g. hysteresis with respect to magnetic field, a ''residual'' second order signal which persists a long time after switching off of the external stationary field and an anomalous behavioUr of the susceptibility at low frequencies. The resemblence of the phenomena observed in the anomalous region with those occurring in spin glasses is noted

  9. Decreasing Ni, Cu, Cd, and Zn heavy metal magnetite-bentonite nanocomposites and adsorption isotherm study

    Science.gov (United States)

    Eskandari, M.; Zakeri Khatir, M.; Khodadadi Darban, A.; Meshkini, M.

    2018-04-01

    This present study was conducted to investigate the effect of magnetite-bentonite nanocomposite on heavy metal removal from an effluent. For this purpose, magnetite-bentonite nanocomposite was prepared through the chemical method and characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, followed by studying the effect of produced nanocomposite on the removal of Ni2+, Cu2+, Cd2+, and Zn2+ heavy metal ions. The results showed that adsorption capacity of magnetite-bentonite nanocomposites for the studied ions is in the order of Zn2+ > Cd2+ > Cu2+ > Ni2+. Adsorption isotherms were drawn for Ni2+, Cu2+, Cd2+, and Zn2+ cations and found that cations adsorption on nanocomposite fit into Langmuir model.

  10. Sub-micron-sized delafossite CuCrO2 with different morphologies ...

    Indian Academy of Sciences (India)

    Abstract. Currently, copper chromium oxide crystallizing in delafossite structure attracts huge research interest due to its versatile applications arising from its layered structure. In this work, delafossite CuCrO2 was synthesized by sol–gel method from their respective hydrated nitrate salts with citric acid as a chelating agent.

  11. Role of metal mixtures (Ca, Cu and Pb) on Cd bioaccumulation and phytochelatin production by Chlamydomonas reinhardtii.

    Science.gov (United States)

    Abboud, Pauline; Wilkinson, Kevin J

    2013-08-01

    The goal of the study was to determine whether metal uptake and biological effects could be predicted by free ion concentrations when organisms were exposed to Cd and a second metal. Bioaccumulation and algal phytochelatin (PC) concentrations were determined for Chlamydomonas reinhardtii following a 6-h exposure. Bioaccumulation results, after six hours of exposure, showed that Cd uptake decreased in the presence of relatively high concentrations of Ca, Cu and Pb, however, Cd bioaccumulation increased in the presence of ca. equimolar concentrations of Cu. A good correlation was observed between the production of PCs and the amount of metals bioaccumulated for the binary mixtures of Cd-Pb and Cd-Cu, but not the Cd-Ca mixture. Overall, the results suggested that, in the case of mixtures, bioaccumulated metal rather than free ion concentrations would be a better predictor of biological effect. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Bonding in d9 complexes derived from EPR: Application to CuCl2-4, CuBr2-4, and CdCl2:Cu2+

    Science.gov (United States)

    Aramburu, J. A.; Moreno, M.

    1985-12-01

    In this work are reported the theoretical expressions for the [g], hyperfine, and superhyperfine (shf) tensors of a d9 square-planar complex within a molecular orbital (MO) scheme. These expressions include contributions arising from crystal field and charge transfer excitations calculated up to third and second order perturbations, respectively. This makes the present framework more general than those previously used. Through those expressions we have derived from the experimental EPR and optical data the MO coefficients corresponding to the valence b1g(x2-y2), b2g(xy), and eg(xz,yz) levels and also the core polarization contribution K to the hyperfine tensor for the systems CuCl2-4, CuBr2-4, and CdCl2:Cu2+. The 3d charge obtained for CuCl2-4 is equal to 0.61, 0.83, and 0.85 for the antibonding 3b1g, 2b2g, and 2eg levels, respectively. These figures are much closer to the Xα results by Bencini and Gatteschi [J. Am. Chem. Soc. 105, 5535 (1983)] than to those by Desjardins et al. [J. Am. Chem. Soc. 105, 4590 (1983)]. The σ and π covalency for CuBr2-4 are both higher than for CuCl2-4 in accord to the lower electronegativity for bromine. However, only for the antibonding 3b1g level of CuBr2-4 have we obtained an electronic charge lying mainly on ligands. The covalency of CdCl2:Cu2+ is smaller than that found for CuCl2-4, a fact associated to a higher metal-ligand distance for the former. Evidence of this statement are also given from the analysis of crystal-field spectra and isotropic shf constant. The values of K derived for CuCl2-4 (128.1×10-4 cm-1), CuBr2-4 (103.6×10-4 cm-1), and CdCl2:Cu2+ (123.9×10-4 cm-1) point out the dependence of K on the equatorial covalency but also on the existence of axial ligands. The [g] tensor of CuBr2-4 is dominated by the charge transfer contribution while the crystal field one is negative. Finally an analysis of the importance of each one of the involved contributions to the spin-Hamiltonian parameters is reported for the

  13. The Effect of Powder Ball Milling on the Microstructure and Mechanical Properties of Sintered Fe-Cr-Mo-Mn-(Cu) Steel

    Science.gov (United States)

    Kulecki, P.; Lichańska, E.

    2017-12-01

    The effect of ball milling powder mixtures of Höganäs pre-alloyed iron Astaloy CrM, low-carbon ferromanganese Elkem, elemental electrolytic Cu and C-UF graphite on the sintered structure and mechanical properties was evaluated. The mixing was conducted using Turbula mixer for 30 minutes and CDI-EM60 frequency inverter for 1 and 2 hours. Milling was performed on 150 g mixtures with (in weight %) CrM + 1% Mn, CrM + 2% Mn, CrM + 1% Mn + 1% Cu and CrM + 2% Mn + 1% Cu, all with 0.6%C. The green compacts were single pressed at 660 MPa according to PN-EN ISO 2740. Sintering was carried out in a laboratory horizontal furnace Carbolite STF 15/450 at 1250°C for 60 minutes in 5%H2 - 95%N2 atmosphere with a heating rate of 75°C/min, followed by sintering hardening at 60°C/min cooling rate. All the steels were characterized by martensitic structures. Mechanical testing revealed that steels based on milled powders have slightly higher mechanical properties compared to those only mixed and sintered. The best combination of mechanical properties, for ball milled CrM + 1% Mn + 1% Cu was UTS 1046 MPa, TRS 1336 MPa and A 1.94%.

  14. Role of metal mixtures (Ca, Cu and Pb) on Cd bioaccumulation and phytochelatin production by Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    Abboud, Pauline; Wilkinson, Kevin J.

    2013-01-01

    The goal of the study was to determine whether metal uptake and biological effects could be predicted by free ion concentrations when organisms were exposed to Cd and a second metal. Bioaccumulation and algal phytochelatin (PC) concentrations were determined for Chlamydomonas reinhardtii following a 6-h exposure. Bioaccumulation results, after six hours of exposure, showed that Cd uptake decreased in the presence of relatively high concentrations of Ca, Cu and Pb, however, Cd bioaccumulation increased in the presence of ca. equimolar concentrations of Cu. A good correlation was observed between the production of PCs and the amount of metals bioaccumulated for the binary mixtures of Cd–Pb and Cd–Cu, but not the Cd–Ca mixture. Overall, the results suggested that, in the case of mixtures, bioaccumulated metal rather than free ion concentrations would be a better predictor of biological effect. -- Highlights: •Cd bioaccumulation and phytochelatin production were evaluated for metal mixtures. •Bioaccumulated metal rather than free ion was a better predictor of biological effect. •Calcium additions decreased Cd bioaccumulation but increased phytochelatin production. •Copper additions increased Cd bioaccumulation and phytochelatin production. •Lead additions had little effect on either Cd bioaccumulation or phytochelatin production. -- In metal mixtures containing Cd and Ca, Pb or Cu, bioaccumulated metal rather than free ion was a better predictor of biological effect

  15. 3D-AP and positron annihilation study of precipitation behavior in Cu-Cr-Zr alloy

    DEFF Research Database (Denmark)

    Hatakeyama, M.; Toyama, T.; Yang, J.

    2009-01-01

    Precipitation behavior in a Cu-0.78%Cr-0.13%Zr alloy during aging and reaging has been studied by laser-assisted local electrode three-dimensional atom probe (Laser-LEAP) and positron annihilation spectroscopy (PAS). After the prime aging at 460 degrees C, Cr clusters enriched with Zr were observed...

  16. Kinetics and equilibrium studies for sorption of Cu (II) and Cr (VI) ions onto polymeric composite resins

    International Nuclear Information System (INIS)

    El-Zahhhar, A.A.; Abdel-Aziz, H.M.; Siyam, T.

    2005-01-01

    The sorption behavior of Cu (II) and Cr (VI) ions from aqueous solutions was studied using polymeric composite resins. Batch sorption experiments were performed as a function of hydrogen ion concentration, complexing agent concentration, resin weight and ionic strength. Kinetic parameters as a function of initial ion concentration were determined to predict the sorption behavior of Cu (II) and Cr (VI) onto polymeric composite resins. The equilibrium data could be fitted by the frendlich adsorption isotherm equation

  17. Short-range ferromagnetism in alloy ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

    Energy Technology Data Exchange (ETDEWEB)

    THANH, P. Q.; HOA, N. Q.; CHAU, N. [Vietnam National University, Hanoi (Viet Nam); HUU, C. X. [Danang University of Technology, Danang (Viet Nam); NGO, D. T. [Technical University of Denmark, Kgs. Lyngby (Denmark); PHAN, T. L. [Chungbuk National University, Cheongju (Korea, Republic of)

    2014-04-15

    We have studied the magnetic properties of two amorphous alloy ribbons Fe{sub 72}Cr{sub 6}Si{sub 4}Nb{sub 5}B{sub 12}Ag{sub 1} (FCSNB-Ag) and Fe{sub 72}Cr{sub 6}Si{sub 4}Nb{sub 5}B{sub 12}Cu{sub 1} (FCSNB-Cu), prepared by using a melt-spinning technique. Magnetization (M) measurements for various temperatures (T) and magnetic fields (H) indicate that ferromagnetic-paramagnetic (FM-PM) phase transitions take place in FCSNB-Ag and FCSNB-Cu at Curie temperatures (T{sub C} ) of about 308.3 K and 322.5 K, respectively. Analyses of M - H data at different temperatures in the vicinity of the FM-PM phase transition based on the modified Arrott plot method and scaling hypothesis yielded the exponent values of β = 0.369 ± 0.005, γ = 1.359 ± 0.005 and δ = 4.7 ± 0.1 for FCSNB-Ag, and β = 0.376 ± 0.002, γ = 1.315 ± 0.006 and δ = 4.5 ± 0.1 for FCSNB-Cu. Compared with the values from theoretical models, these values are close to those expected for the 3D Heisenberg model, demonstrating the existence of short-range FM order in the amorphous alloy ribbons.

  18. Simulated solarlight catalytic reduction of Cr(VI) on microwave–ultrasonication synthesized flower-like CuO in the presence of tartaric acid

    International Nuclear Information System (INIS)

    Xu, Zhihui; Yu, Yaqun; Fang, Di; Liang, Jianru; Zhou, Lixiang

    2016-01-01

    In this study, flower-like CuO was successfully synthesized by a microwave–ultrasound assisted method and well characterized by X-ray diffractions, Fourier transform infrared spectrum, scanning electron microscopy, transmission electron microscopy, specific surface area, UV–vis diffused reflection spectra, X-ray photoelectron spectroscopy and point of zero charge. The photocatalytic performance of the as-prepared CuO was examined on the Cr(VI) reduction in the presence of tartaric acid under simulated solarlight irradiation. The results show that the developed CuO catalyst exhibited good photocatalytic activity with 100% reduction of Cr(VI) after irradiation of 30 min under the test condition of c(Cr(VI)) = 100 μM, catalyst loading = 400 mg/L, c(tartaric acid) = 4 mM and initial pH = 3. The reaction mechanism was proposed. The effects of test parameters, such as catalyst loading, tartaric acid concentration and initial pH, on Cr(VI) reduction efficiency were also investigated. It is worth mentioning that the developed catalyst can work at a relatively wide range of pH with quite high catalytic performance. - Highlights: • Flower-like CuO microstructure was prepared by MW-US assisted method. • The prepared CuO can catalyze the reduction Cr(VI) by tartaric acid under simulated solarlight. • The formation of ≡Cu(II)-tartaric acid complex play a key role in the reduction of Cr(VI). • The catalyst can operate effectively at a relatively wide range of pH.

  19. Fabrication of mock-up with Be armour tiles diffusion bonded to the CuCrZr heat sink

    International Nuclear Information System (INIS)

    Moreschi, L.F.; Pizzuto, A.; Alessandrini, I.; Agostini, M.; Visca, E.; Merola, M.

    2001-01-01

    The aim of this work is the manufacture of high heat flux mock-ups with Be armour tiles on a CuCrZr heat sink for fabricating the beryllium section of the divertor vertical target (DVT) in the ITER reactor. Diffusion bonding between the CuCrZr bar and the beryllium tiles was obtained by inserting an aluminium interlayer to accommodate surface irregularities as well as to provide a compliant layer for accommodating thermal mismatches during both manufacturing and operation and cycles

  20. Zn, Pb, Cr and Cd concentrations in fish, water and sediment from ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Zn, Pb, Cr and Cd concentrations in fish, water and sediment from the Azuabie Creek,. Port Harcourt. ... Heavy metal contamination in the aquatic ... Azuabie Creek and the associated water ..... Public in Tianjin, China via Consumption of.

  1. Effect of Cr, Ti, V, and Zr Micro-additions on Microstructure and Mechanical Properties of the Al-Si-Cu-Mg Cast Alloy

    Science.gov (United States)

    Shaha, S. K.; Czerwinski, F.; Kasprzak, W.; Friedman, J.; Chen, D. L.

    2016-05-01

    Uniaxial static and cyclic tests were used to assess the role of Cr, Ti, V, and Zr additions on properties of the Al-7Si-1Cu-0.5Mg (wt pct) alloy in as-cast and T6 heat-treated conditions. The microstructure of the as-cast alloy consisted of α-Al, eutectic Si, and Cu-, Mg-, and Fe-rich phases Al2.1Cu, Al8.5Si2.4Cu, Al5.2CuMg4Si5.1, and Al14Si7.1FeMg3.3. In addition, the micro-sized Cr/Zr/Ti/V-rich phases Al10.7SiTi3.6, Al6.7Si1.2TiZr1.8, Al21.4Si3.4Ti4.7VZr1.8, Al18.5Si7.3Cr2.6V, Al7.9Si8.5Cr6.8V4.1Ti, Al6.3Si23.2FeCr9.2V1.6Ti1.3, Al92.2Si16.7Fe7.6Cr8.3V1.8, and Al8.2Si30.1Fe1.6Cr18.8V3.3Ti2.9Zr were present. During solution treatment, Cu-rich phases were completely dissolved, while the eutectic silicon, Fe-, and Cr/Zr/Ti/V-rich intermetallics experienced only partial dissolution. Micro-additions of Cr, Zr, Ti, and V positively affected the alloy strength. The modified alloy in the T6 temper during uniaxial tensile tests exhibited yield strength of 289 MPa and ultimate tensile strength of 342 MPa, being significantly higher than that for the Al-Si-Cu-Mg base. Besides, the cyclic yield stress of the modified alloy in the T6 state increased by 23 pct over that of the base alloy. The fatigue life of the modified alloy was substantially longer than that of the base alloy tested using the same parameters. The role of Cr, Ti, V, and Zr containing phases in controlling the alloy fracture during static and cyclic loading is discussed.

  2. Bioaccessibility of As, Cd, Cu, Ni, Pb, and Sb in toys and low-cost jewelry.

    Science.gov (United States)

    Guney, Mert; Zagury, Gerald J

    2014-01-21

    Children can be exposed to toxic elements in toys and jewelry following ingestion. As, Cd, Cu, Ni, Pb, and Sb bioavailability was assessed (n = 24) via the in vitro gastrointestinal protocol (IVG), the physiologically based extraction test (PBET), and the European Toy Safety Standard protocol (EN 71-3), and health risks were characterized. Cd, Cu, Ni, and Pb were mobilized from 19 metallic toys and jewelry (MJ) and one crayon set. Bioaccessible Cd, Ni, or Pb exceeded EU migratable concentration limits in four to six MJ, depending on the protocol. Using two-phase (gastric + intestinal) IVG or PBET might be preferable over EN 71-3 since they better represent gastrointestinal physiology. Bioaccessible and total metal concentrations were different and not always correlated, indicating that bioaccessibility measurement may provide more accurate risk characterization. More information on impacts of multiple factors affecting metals mobilization from toys and jewelry is needed before recommending specific tests. Hazard index (HI) for Cd, Ni, or Pb were >1 for all six MJ exceeding the EU limits. For infants (6-12 mo old), 10 MJ had HI > 1 for Cd, Cu, Ni, or Pb (up to 75 for Cd and 43 for Pb). Research on prolonged exposure to MJ and comprehensive risk characterization for toys and jewelry exposure is recommended.

  3. Relationship between firewood usage and urinary Cr, Cu and As in ...

    African Journals Online (AJOL)

    All participants answered a questionnaire concerning exposure and were tested for urinary Cr, Cu and As, while the urine of 29 participants was also tested for toxic As (As(tox)). Results. Multivariate analysis showed that the time spent in close proximity to the wood, as well as the quantity of wood used for cooking and for ...

  4. Effect of hydrostatic pressure on the structural and electronic properties of Cd{sub 0.75}Cr{sub 0.25}S

    Energy Technology Data Exchange (ETDEWEB)

    Rani, Anita [Guru Nanak College for Girls, Sri Muktsar Sahib Punjab-152026 (India); Kaur, Kulwinder; Kumar, Ranjan [Department of Physics, Panjab University Chandigarh-160014 (India); Dhiman, Shobna [Department of Applied Science, PEC, University of Technology, Chandigarh-160011 (India)

    2016-05-23

    In this paper we present the results obtained from first principle calculations of the effect of hydrostatic pressure on the structural and electronic properties of Cd{sub 1-x}Cr{sub x}S diluted magnetic semiconductor in Zinc Blende (B3) phase at x=0.25. High pressure behavior of Cd{sub 1-x}Cr{sub x}S has been investigated between 0 GPa to 100 GPa The calculations have been performed using Density functional theory as implemented in the Spanish Initiative for Electronic Simulations with Thousands of Atoms code using local density approximation as exchange-correlation (XC) potential. Calculated electronic band structures of Cd{sub 1-x}Cr{sub x}S are discussed in terms of contribution of Cr 3d{sup 5} 4s{sup 1}, Cd 4d{sup 10} 5s{sup 2}, S 3s{sup 2} 3p{sup 4} orbital’s. Study of band structures shows half-metallic ferromagnetic nature of Cd{sub 0.75}Cr{sub 0.25}S with 100% spin polarization. Under application of external pressure, the valence band and conduction band are shifted upward which leads to modification of electronic structure.

  5. Assessment of Pb, Zn, Cu, Ni and Cr in vegetables grown around Zanjan

    Directory of Open Access Journals (Sweden)

    A. Afshari

    2017-05-01

    Full Text Available This study was conducted aimed to assess the potential risk of heavy metals on human health resulting from consumption of vegetables. To this end, the vegetables grown around town and industrial center of Zanjan were sampled randomly. Plant samples were digested using hydrochloric acid (HCL 2 M and concentration of elements (Pb, Zn, Cu, Ni and Cr were recorded by atomic absorption. Obtained means of heavy metals in all vegetables (N= 32 for Zn, Pb, Cu, Ni and Cr is 98.8, 31.9, 19.3, 4.4 and 2.3 mg/kg, respectively. The highest amount of metal pollution index (MPI in the basil and the lowest was observed in the garden cress (respectively 16.46 and 4.88. Daily intake (EDI for zinc, copper and chromium in all age groups was lower than the provisional tolerable daily intake (PTDI. This amount for nickel was 2, 1.6 and 1.3 %, and for Pb 28.1, 22 and 19 % higher than PTDI in children, adults and seniors, respectively. The potential risk (THQ was calculated in all age groups as Pb>>Cu>Zn>Ni>Cr. The potential risks (THQ of chromium, nickel and zinc were calculated lower than 1, for copper a bit more of 1 and for lead much higher than 1. Health index (HI for children, adults and the elderly was estimated 31.331, 24.58 and 21.14, respectively, with the largest contribution of the lead (89.7%.

  6. The effect of 3 wt.% Cu addition on the microstructure, tribological property and corrosion resistance of CoCrW alloys fabricated by selective laser melting.

    Science.gov (United States)

    Luo, Jiasi; Wu, Songquan; Lu, Yanjin; Guo, Sai; Yang, Yang; Zhao, Chaoqian; Lin, Junjie; Huang, Tingting; Lin, Jinxin

    2018-03-19

    Microstructure, tribological property and corrosion resistance of orthopedic implant materials CoCrW-3 wt.% Cu fabricated by selective laser melting (SLM) process were systematically investigated with CoCrW as control. Equaxied γ-phase together with the inside {111}  type twin and platelet ε-phase was found in both the Cu-bearing and Cu-free alloys. Compared to the Cu-free alloy, the introduction of 3 wt.% Cu significantly increased the volume fraction of the ε-phase. In both alloys, the hardness of ε-phase zone was rather higher (~4 times) than that of γ-phase zone. The wear factor of 3 wt.% Cu-bearing alloy possessed smaller wear factor, although it had higher friction coefficient compared with Cu-free alloys. The ε-phase in the CoCr alloy would account for reducing both abrasive and fatigue wear. Moreover, the Cu-bearing alloy presented relatively higher corrosion potential E corr and lower corrosion current density I corr compared to the Cu-free alloy. Accordingly, 3 wt.% Cu addition plays a key role in enhancing the wear resistance and corrosion resistance of CoCrW alloys, which indicates that the SLM CoCrW-3Cu alloy is a promising personalized alternative for traditional biomedical implant materials.

  7. A facile synthesis and spectral characterization of Cu{sup 2+} doped CdO/ZnS nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Joyce Stella, R.; Thirumala Rao, G.; Babu, B.; Pushpa Manjari, V. [Department of Physics, University College of Sciences, Acharya Nagarjuna University, Nagarjuna Nagar, AP 522510 (India); Reddy, Ch. Venkata; Shim, Jaesool [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Ravikumar, R.V.S.S.N., E-mail: rvssn@yahoo.co.in [Department of Physics, University College of Sciences, Acharya Nagarjuna University, Nagarjuna Nagar, AP 522510 (India)

    2015-06-15

    A facile two-step method is demonstrated for the preparation of Cu{sup 2+} doped CdO/ZnS nanocomposite. Systematic investigations like X-ray diffraction (XRD), Scanning electron microscopy (SEM) with EDS, transmission electron microscopy (TEM), FT-IR, electron paramagnetic resonance (EPR), optical absorption, photoluminescence (PL) and magnetic studies are carried out for the prepared material. From powder XRD, the nanocomposites are comprised for cubic phase of both CdO and ZnS in a close contact with each other. The ground state wave function of dopant ions has been estimated from EPR studies. Optical and EPR data confirm that doped Cu{sup 2+}ions occupy rhombically distorted octahedral sites with the host material. Due to doping, band gap has been changed and blue shifts occurred in PL. Magnetic measurements indicate a possible ferromagnetic response, associated to the exchange interaction between local spin-polarized electrons of Cu{sup 2+} ions and conductive electrons. - Graphical abstract: M–H curve of Cu{sup 2+} doped CdO–ZnS nanocomposites. The magnetic properties of Cu{sup 2+} doped CdO/ZnS nanocomposite has been investigated using vibrating sample magnetometer given as magnetization and hysteresis (M–H) curve. The magnetization curve with noticeable coercivity of M–H loop clearly indicate the existence of ferromagnetic ordering in Cu{sup 2+} doped CdO/ZnS nanocomposite at room temperature. According to the Ruderman–Kittel–Kasuya–Yosida (RKKY) theory, the exchange interaction between local spin-polarized electrons (such as the electrons of Cu{sup 2+} ions) and conductive electrons is the main cause that leads to the ferromagnetism. Coercivity (Hc) of the field is about 98 Oe, saturation magnetization (Ms) and remnant magnetization (Mr) of present sample is estimated to be 15.8×10{sup −3} and 1.43×10{sup −3} emu/g respectively. The ferromagnetism observed in the prepared material is not commencing with other impurities but expected to

  8. Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

    African Journals Online (AJOL)

    Comparison of trace element contamination levels (Cu, Zn, Fe, Cd and Pb) in the soft tissues of the gastropods Tympanotonus fuscatus fuscatus and Tf radula collected in the Ebrié Lagoon (Côte d'Ivoire): Evidence of the risks linked to linked to lead and.

  9. Biosorption kinetics of Cd (II, Cr (III and Pb (II in aqueous solutions by olive stone

    Directory of Open Access Journals (Sweden)

    M. Calero

    2009-06-01

    Full Text Available A by-product from olive oil production, olive stone, was investigated for the removal of Cd (II, Cr (III and Pb (II from aqueous solutions. The kinetics of biosorption are studied, analyzing the effect of the initial concentration of metal and temperature. Pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models have been used to represent the kinetics of the process and obtain the main kinetic parameters. The results show that the pseudo-second order model is the one that best describes the biosorption of the three metal ions for all the range of experimental conditions investigated. For the three metal ions, the maximum biosoption capacity and the initial biosorption rate increase when the initial metal concentration rises. However, the kinetic constant decreases when the initial metal concentration increases. The temperature effect on biosorption capacity for Cd (II and Cr (III is less significant; however, for Pb (II the effect of temperature is more important, especially when temperature rises from 25 to 40ºC. The biosorption capacity at mmol/g of olive stone changes in the following order: Cr>Cd>Pb. Thus, for an initial concentration of 220 mg/ℓ, a maximum sorption capacity of 0.079 mmol/g for Cr (III, 0.065 mmol/g for Cd (II and 0.028 mmol/g for Pb (II has been obtained.

  10. Lattice parameter values and phase transitions for the Cu{sub 2}Cd{sub 1-z}Mn {sub z}GeSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe {sub z}GeSe{sub 4} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Quintero, E. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Tovar, R. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Quintero, M. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)]. E-mail: mquinter@ula.ve; Delgado, G.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Morocoima, M. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Caldera, D. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Ruiz, J. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Mora, A.E. [Laboratorio de Analisis Quimico y Estructural de Materiales, Departamento de Fisica, Universidad de Los Andes, Merida 5101 (Venezuela); Briceno, M. [Laboratorio de Analisis Quimico y Estructural de Materiales, Departamento de Fisica, Universidad de Los Andes, Merida 5101 (Venezuela); Fernandez, J.L. [Laboratorio de Analisis Quimico y Estructural de Materiales, Departamento de Fisica, Universidad de Los Andes, Merida 5101 (Venezuela)

    2007-04-25

    X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu{sub 2}Cd{sub 1-z}Mn {sub z}GeSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe {sub z}GeSe{sub 4} alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. The effect of the annealing temperature and cooling rate to room temperature are discussed. For the Cu{sub 2}Cd{sub 1-z}Fe {sub z}GeSe{sub 4} system, only two single solid phase fields, the tetragonal stannite {alpha} and the wurtz-stannite {delta} structures were found to occur in the diagram. For the Cu{sub 2}Cd{sub 1-z}Mn {sub z}GeSe{sub 4} system, in addition to the tetragonal stannite {alpha} and the wurtz-stannite {delta} phases, MnSe was found to exist in the diagram. The DTA experiments showed that the cooling curves for both systems exhibited effects of undercooling.

  11. Theoretical study of heavy metal Cd, Cu, Hg, and Ni(II) adsorption on the kaolinite(0 0 1) surface

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jian, E-mail: zhaojian0209@aliyun.com [Institute of Applied Physics and Computational Mathematics, PO Box 8009, Beijing 100088 (China); State Key Laboratory of Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083 (China); He, Man-Chao [State Key Laboratory of Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083 (China)

    2014-10-30

    Highlights: • We investigated the adsorption of Cd, Cu, Hg, and Ni(II) on kaolinite(0 0 1) surface. • The adsorption capabilities of the kaolinite for HM atoms were Ni > Cu > Cd > Hg(II). • The adsorption energy increases with the coverage for Cd, Cu, and Hg(II) atoms. • The adsorption energy decreases with the coverage for Ni(II) atoms. - Abstract: Heavy metal pollution is currently of great concern because it has been recognized as a potential threat to air, water, and soil. Adsorption was one of the most popular methods for the removal of heavy metal. The adsorption of heavy metal Cd, Cu, Hg, and Ni(II) atoms on the hydroxylated (0 0 1) surface of kaolinite was investigated using density-functional theory within the generalized gradient approximation and a supercell approach. The coverage dependence of the adsorption structures and energetics were systematically studied for a wide range of coverage Θ [from 0.11 to 1.0 monolayers (ML)] and adsorption sites. The most stable among all possible adsorption sites for Cd(II) atom was the two-fold bridge site followed by the one-fold top site, and the top site was the most favorite adsorption site for Cu and Ni(II) atoms, while the three-fold hollow site was the most stable adsorption site for Hg(II) atom followed by the two-fold bridge site. The adsorption energy increases with the coverage for Cd, Cu, and Hg(II) atoms, thus indicating the higher stability of surface adsorption and a tendency to the formation of adsorbate islands (clusters) with increasing the coverage. However, the adsorption energy of Ni(II) atoms decreases when increasing the coverage. The adsorption capabilities of the kaolinite clay for the heavy metal atoms were in the order of Ni > Cu > Cd > Hg(II). The other properties of the Cd, Cu, Hg, and Ni(II)/kaolinite(0 0 1) system including the different charge distribution, the lattice relaxation, and the electronic density of states were also studied and discussed in detail.

  12. Theoretical study of heavy metal Cd, Cu, Hg, and Ni(II) adsorption on the kaolinite(0 0 1) surface

    International Nuclear Information System (INIS)

    Zhao, Jian; He, Man-Chao

    2014-01-01

    Highlights: • We investigated the adsorption of Cd, Cu, Hg, and Ni(II) on kaolinite(0 0 1) surface. • The adsorption capabilities of the kaolinite for HM atoms were Ni > Cu > Cd > Hg(II). • The adsorption energy increases with the coverage for Cd, Cu, and Hg(II) atoms. • The adsorption energy decreases with the coverage for Ni(II) atoms. - Abstract: Heavy metal pollution is currently of great concern because it has been recognized as a potential threat to air, water, and soil. Adsorption was one of the most popular methods for the removal of heavy metal. The adsorption of heavy metal Cd, Cu, Hg, and Ni(II) atoms on the hydroxylated (0 0 1) surface of kaolinite was investigated using density-functional theory within the generalized gradient approximation and a supercell approach. The coverage dependence of the adsorption structures and energetics were systematically studied for a wide range of coverage Θ [from 0.11 to 1.0 monolayers (ML)] and adsorption sites. The most stable among all possible adsorption sites for Cd(II) atom was the two-fold bridge site followed by the one-fold top site, and the top site was the most favorite adsorption site for Cu and Ni(II) atoms, while the three-fold hollow site was the most stable adsorption site for Hg(II) atom followed by the two-fold bridge site. The adsorption energy increases with the coverage for Cd, Cu, and Hg(II) atoms, thus indicating the higher stability of surface adsorption and a tendency to the formation of adsorbate islands (clusters) with increasing the coverage. However, the adsorption energy of Ni(II) atoms decreases when increasing the coverage. The adsorption capabilities of the kaolinite clay for the heavy metal atoms were in the order of Ni > Cu > Cd > Hg(II). The other properties of the Cd, Cu, Hg, and Ni(II)/kaolinite(0 0 1) system including the different charge distribution, the lattice relaxation, and the electronic density of states were also studied and discussed in detail

  13. Ecological effects of some heavy metals (Cd, Pb, Hg, Cr) pollution of ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-06-17

    Jun 17, 2008 ... Accumulation of heavy metals (Cd, Pb, Hg, Cr) in water and plankton of Sarıyar Dam Lake (SDR) was seasonally ... human impacts in protected areas with the aim of .... (1999), heavy metals toxicity is affected by temperature,.

  14. Determination of Ti, Cr, Cu and Ta in niobium oxide by X-ray fluorescence method

    International Nuclear Information System (INIS)

    Dixit, R.M.; Deshpande, S.S.

    1986-01-01

    An x-ray fluorescence method for the determination of Ti, Cr, Cu and Ta in niobium oxide has been developed. Samples/standards in powder form are mixed with boric acid in the proportion of 1:1 (400 mg. each). Double layer pellets are prepared by pressing this mixture over a primary boric acid pellet. Philips PW-1220, a semiautomatic x-ray spectrometer with tungsten target x-ray tube for excitation and LiF (200) crystal for dispersion have been used. The determination range is from 0.005 to 0.1per cent for Ti and Cr, 0.01 to 0.1per cent for Cu and 0.05 to 1per cent for Ta. (author)

  15. The influence of biochar type on long-term stabilization for Cd and Cu in contaminated paddy soils.

    Science.gov (United States)

    Li, Hongying; Ye, Xinxin; Geng, Zhigang; Zhou, Hongjian; Guo, Xisheng; Zhang, Yunxia; Zhao, Huijun; Wang, Guozhong

    2016-03-05

    Long-term effect of biochar on PTEs (potential toxic elements) immobilization depends upon biochar own property and its aging process in soil. To understand the role of biachar type on PTEs stabilization, two types of biochar, corn-straw-derived biochar (CB) and hardwood-derived biochar (HB), were compared for their efficacy in achieving a stable decrease in the bio-availability of Cd and Cu in soils. The 3-year pot-culture experiment showed that HB reduced the concentration of CaCl2-extractable Cd and Cu by 57.9 and 63.8% in soil, and Cd and Cu uptake by 63.6 and 56.3% in rice tissue respectively, in the first year, whereas these values increased in the next two years. On the other hand, CB decreased these values steadily year by year. At the end of the 3 years, CB at 5% level had lowered the levels of CaCl2-extractable Cd and Cu by 53.6 and 66.8%, respectively. These variations between CB and HB were due to the differences in the way the two types of biochar age in the soil. The aging process was simulated in the laboratory, and the XPS results showed that the oxidization of the biochars introduced more oxygen-containing groups (especially carboxyl) on the surface of CB than HB, leading to a correspondingly greater number of oxygenated binding sites for Cd and Cu in the case of CB. The content of lignin was the major factor resulting in the variation of oxidation degree in two biochars. These results suggest that it is important to select the right kind of biochar to stably decrease the bio-availability of potential toxic elements (Cd and Cu) in contaminated soils. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Effect of interfacial defects on the electronic and magnetic properties of epitaxial CrAs/InAs and CrAs/CdSe half-metallic multilayers

    International Nuclear Information System (INIS)

    Galanakis, I.; Lekkas, I.

    2010-01-01

    We present an extended study of single impurity atoms at the interface between the half-metallic ferromagnetic zinc-blende CrAs compound and the zinc-blende binary InAs and CdSe semiconductors in the form of very thin multilayers. Contrary to the case of impurities in the perfect bulk CrAs studied in Galanakis and Pouliasis [J. Magn. Magn. Mater. 321 (2009) 1084] defects at the interfaces do not alter in general the half-metallic character of the perfect systems. The only exception are Void impurities at Cr or In(Cd) sites which lead, due to the lower-dimensionality of the interfaces with respect to the bulk CrAs, to a shift of the p bands of the nearest neighboring As(Se) atom to higher energies and thus to the loss of the half-metallicity. But Void impurities are Schottky-type and should exhibit high formation energies and thus we expect the interfaces in the case of thin multilayers to exhibit a robust half-metallic character.

  17. PET Imaging of Abdominal Aortic Aneurysm with 64Cu-Labeled Anti-CD105 Antibody Fab Fragment.

    Science.gov (United States)

    Shi, Sixiang; Orbay, Hakan; Yang, Yunan; Graves, Stephen A; Nayak, Tapas R; Hong, Hao; Hernandez, Reinier; Luo, Haiming; Goel, Shreya; Theuer, Charles P; Nickles, Robert J; Cai, Weibo

    2015-06-01

    The critical challenge in abdominal aortic aneurysm (AAA) research is the accurate diagnosis and assessment of AAA progression. Angiogenesis is a pathologic hallmark of AAA, and CD105 is highly expressed on newly formed vessels. Our goal was to use (64)Cu-labeled anti-CD105 antibody Fab fragment for noninvasive assessment of angiogenesis in the aortic wall in a murine model of AAA. Fab fragment of TRC105, a mAb that specifically binds to CD105, was generated by enzymatic papain digestion and conjugated to NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid) for (64)Cu labeling. The binding affinity/specificity of NOTA-TRC105-Fab was evaluated by flow cytometry and various ex vivo studies. BALB/c mice were anesthetized and treated with calcium phosphate to induce AAA and underwent weekly PET scans using (64)Cu-NOTA-TRC105-Fab. Biodistribution and autoradiography studies were also performed to confirm the accuracy of PET results. NOTA-TRC105-Fab exhibited high purity and specifically bound to CD105 in vitro. Uptake of (64)Cu-NOTA-TRC105-Fab increased from a control level of 3.4 ± 0.1 to 9.5 ± 0.4 percentage injected dose per gram (%ID/g) at 6 h after injection on day 5 and decreased to 7.2 ± 1.4 %ID/g on day 12, which correlated well with biodistribution and autoradiography studies (i.e., much higher tracer uptake in AAA than normal aorta). Of note, enhanced AAA contrast was achieved, due to the minimal background in the abdominal area of mice. Degradation of elastic fibers and highly expressed CD105 were observed in ex vivo studies. (64)Cu-NOTA-TRC105-Fab cleared rapidly through the kidneys, which enabled noninvasive PET imaging of the aorta with enhanced contrast and showed increased angiogenesis (CD105 expression) during AAA. (64)Cu-NOTA-TRC105-Fab PET may potentially be used for future diagnosis and prognosis of AAA. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  18. Simulation of cathode spot crater formation and development on CuCr alloy in vacuum arc

    Science.gov (United States)

    Wang, Lijun; Zhang, Xiao; Wang, Yuan; Yang, Ze; Jia, Shenli

    2018-04-01

    The two-dimensional (2D) rotary axisymmetric model is used to describe the formation and development of a cathode spot on a copper-chromium alloy (CuCr) in a vacuum arc. The model includes hydrodynamic equations and the heat transfer equation. Parameters used in this model come from experiments and other researchers' work. The influence of parameters is analyzed, and the simulation results are compared with pure metal simulation results. In simulation, the depth of the cathode crater is from 0.5 μm to 1.1 μm, the radius of the cathode crater is from 1.6 μm to 2.6 μm, the maximum velocity of the droplet is from 200 m/s to 600 m/s, and the maximum temperature is from 3500 K to 5000 K which is located in the area with a radius of 0.5-1.5 μm. The simulation results show that a smooth cathode surface is advantageous for reducing ablation, the ablation on the CuCr alloy is smaller than that on the pure metal cathode electrode, and the cathode spot appears on the chromium grain only on CuCr. The simulation results are in good agreement with the experiment.

  19. Mechanical characterization and modeling of brazed tungsten and Cu-Cr-Zr alloy using stress relief interlayers

    Science.gov (United States)

    Qu, Dandan; Zhou, Zhangjian; Yum, Youngjin; Aktaa, Jarir

    2014-12-01

    A rapidly solidified foil-type Ti-Zr based amorphous filler with a melting temperature of 850 °C was used to braze tungsten to Cu-Cr-Zr alloy for water cooled divertors and plasma facing components application. Brazed joints of dissimilar materials suffer from a mismatch in coefficients of thermal expansion. In order to release the residual stress caused by the mismatch, brazed joints of tungsten and Cu-Cr-Zr alloy using different interlayers were studied. The shear strength tests of brazed W/Cu joints show that the average strength of the joint with a W70Cu30 composite plate interlayer reached 119.8 MPa, and the average strength of the joint with oxygen free high conductivity copper (OFHC Cu)/Mo multi-interlayers reached 140.8 MPa, while the joint without interlayer was only 16.6 MPa. Finite element method (FEM) has been performed to investigate the stress distribution and effect of stress relief interlayers. FEM results show that the maximum von Mises stress occurs in the tungsten/filler interface and that the filler suffers the peak residual stresses and becomes the weakest zone. And the use of OFHC Cu/Mo multi-interlayers can reduce the residual stress significantly, which agrees with the mechanical experiment data.

  20. Specific features of band structure and optical anisotropy of Cu{sub 2}CdGeSe{sub 4} quaternary compounds

    Energy Technology Data Exchange (ETDEWEB)

    Brik, M.G., E-mail: brik@fi.tartu.ee [College of Mathematics and Physics, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia); Institute of Physics, Jan Dlugosz University, Armii Krajowej 13/15, PL-42200 Czestochowa (Poland); Parasyuk, O.V. [Department of Chemistry, Eastern European National University, Voli 13, Lutsk 43025 (Ukraine); Myronchuk, G.L. [Department of Physics, Eastern European National University, Voli 13, Lutsk 43025 (Ukraine); Kityk, I.V. [Institute of Materials Science and Engineering, Technical University of Czestochowa, Al. Armii Krajowej 19, 42-200 Czestochowa (Poland)

    2014-09-15

    Complex theoretical and experimental studies of the band structure and optical functions of a new Cu{sub 2}CdGeSe{sub 4} quaternary crystal are reported. The benchmark band structure calculations were performed using the first-principles methods. As a result, the structural, electronic, optical and elastic properties of Cu{sub 2}CdGeSe{sub 4} were calculated in the general gradient approximation (GGA) and local density approximation (LDA). The calculated dielectric function and optical absorption spectra exhibit some anisotropic behavior. Detailed analysis of the band energy dispersion and effective space charge density helped in establishing the origin of the band structure anisotropy. All calculated properties are compared with the experimental data. An additional comparison with a similar crystal of Cu{sub 2}CdGeSe{sub 4} allowed to reveal the role played by the anions (S or Se) in formation of the optical properties of these two materials. - Highlights: • The structural, electronic, optical properties of Cu{sub 2}CdGeSe{sub 4} were calculated. • Pressure effects on these properties were modeled. • Comparison with a similar compound of Cu{sub 2}CdGeS{sub 4} was performed.

  1. One-pot noninjection synthesis of Cu-doped Zn(x)Cd(1-x)S nanocrystals with emission color tunable over entire visible spectrum.

    Science.gov (United States)

    Zhang, Wenjin; Zhou, Xinggui; Zhong, Xinhua

    2012-03-19

    Unlike Mn doped quantum dots (d-dots), the emission color of Cu dopant in Cu d-dots is dependent on the nature, size, and composition of host nanocrystals (NCs). The tunable Cu dopant emission has been achieved via tuning the particle size of host NCs in previous reports. In this paper, for the first time we doped Cu impurity in Zn(x)Cd(1-x)S alloyed NCs and tuned the dopant emission in the whole visible spectrum via variation of the stoichiometric ratio of Zn/Cd precursors in the host Zn(x)Cd(1-x)S alloyed NCs. A facile noninjection and low cost approach for the synthesis of Cu:Zn(x)Cd(1-x)S d-dots was reported. The optical properties and structure of the obtained Cu:Zn(x)Cd(1-x)S d-dots have been characterized by UV-vis spectroscopy, photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The influences of various experimental variables, including Zn/Cd ratio, reaction temperature, and Cu dopant concentration, on the optical properties of Cu dopant emission have been systematically investigated. The as-prepared Cu:Zn(x)Cd(1-x)S d-dots did show PL emission but with quite low quantum yield (QY) (typically below 6%). With the deposition of ZnS shell around the Cu:Zn(x)Cd(1-x)S core NCs, the PL QY increased substantially with a maximum value of 65%. More importantly, the high PL QY can be preserved when the initial oil-soluble d-dots were transferred into aqueous media via ligand replacement by mercaptoundeconic acid. In addition, these d-dots have thermal stability up to 250 °C. © 2012 American Chemical Society

  2. Desorption dynamics of deuterium in CuCrZr alloy

    Science.gov (United States)

    Thi Nguyen, Lan Anh; Lee, Sanghwa; Noh, S. J.; Lee, S. K.; Park, M. C.; Shu, Wataru; Pitcher, Spencer; Torcy, David; Guillermain, David; Kim, Jaeyong

    2017-12-01

    Desorption behavior of deuterium (D2) in CuCrZr alloy was investigated considering sample thickness, loading and baking temperature of deuterium followed by the ITER scopes. Cylindrical specimens of 1, 3, 5 mm thick with 4 mm diameter were exposed to deuterium at a pressure of 25 bar at 120, 240 and 350 °C for 24 h, then baked at 800 °C in a vacuum chamber maintained at a pressure lower than 10-7 Torr. Deuterium desorption characteristics such as desorption rate and amount of deuterium in the sample were estimated by analyzing the desorption peaks monitored with a residual gas analyzer (RGA), and the trapping energy of deuterium was calculated using thermal desorption spectroscopy (TDS). Secondary ion mass spectroscopy (SIMS) results showed that deuterium atoms embedded in the sample at a depth of less than 15 μm and desorbed as low as 400 °C. All absorbed deuterium atoms in the specimen were completely retrieved by dynamic pumping at 800 °C in 15 min. The desorption rate of deuterium per unit area was inversely proportional to the increment of the thickness of the sample, and was proportional to the loading temperature. Based on the assumption that a uniform distribution of interstitial sites for deuterium follows the Femi-Dirac statistics, the result of TDS demonstrated that the CuCrZr alloy has two types of trapping energies, which were estimated to be 62 and 79 kJ/mol.

  3. Modification of electrospun polyacrylonitrile nanofibers with EDTA for the removal of Cd and Cr ions from water effluents

    Energy Technology Data Exchange (ETDEWEB)

    Chaúque, Eutilério F.C., E-mail: efchauque@gmail.com [Department of Applied Chemistry, University of Johannesburg, Doornfontein 2028, Johannesburg (South Africa); Dlamini, Langelihle N., E-mail: lndlamini@uj.ac.za [Department of Applied Chemistry, University of Johannesburg, Doornfontein 2028, Johannesburg (South Africa); Adelodun, Adedeji A., E-mail: aadelodun@uj.ac.za [Department of Applied Chemistry, University of Johannesburg, Doornfontein 2028, Johannesburg (South Africa); Greyling, Corinne J., E-mail: GreylingC@cput.ac.za [Technology Station in Clothing and Textiles, Cape Peninsula University of Technology, Symphony Way, Bellville, 7535 (South Africa); Catherine Ngila, J., E-mail: jcngila2002@yahoo.com [Department of Applied Chemistry, University of Johannesburg, Doornfontein 2028, Johannesburg (South Africa)

    2016-04-30

    Graphical abstract: - Highlights: • Polyscrylonitrile (PAN) nanofibers prepared through electrospinning and chemically modified with ethylenediaminetetraacetic acid using ethylenediamine crosslinker. • Fabricated nanofibers have enhanced surface chemistry with insignificant impact on the nanofibrous structure. • Excellent maximum adsorption capacities of 66.24 and 32.68 mg g{sup −1} toward Cr and Cd ions, respectively. • A pre-concentration factor of 19 achieved for removal of Cd and Cr in environmental water samples. - Abstract: Polyacrylonitrile (PAN) nanofibers were obtained by electrospinning technique prior to surface modification with polyethylenediaminetetraacetic acid (EDTA) using ethylenediamine (EDA) as the cross-linker. The modified nanofibers (EDTA-EDA-PAN) were subsequently applied in the wastewater treatment for the removal of Cd(II) and Cr(VI). Textural and chemical characterizations of the nanofibers were carried out by analysis of the specific surface area (Brauner Emmet and Teller (BET)) and thermogravimetric analyses, scanning electron microscopy and Fourier transform infrared spectroscopy. From the adsorption equilibrium studies with Langmuir, Freundlich and Temkin isotherm models, Freundlich was found most suitable for describing the removal mechanism of the target metals as they collect on a heterogeneously functionalized polymer surface. The EDTA-EDA-PAN nanofibers showed effective sorption affinity for both Cd(II) and Cr(VI), achieving maximum adsorption capacities of 32.68 and 66.24 mg g{sup -1}, respectively, at 298 K. In furtherance, the nanofibers were regenerated by simple washing with 2 M HCl solution. Conclusively, the EDTA-EDA-PAN nanofibers were found to be efficient for the removal of Cd(II) and Cr(VI) in water effluents.

  4. Study of bioaccumulation and biotransformation by microanalytical X-ray techniques: investigation of distribution and speciation of Cu and Cr in the body of the plant-feeding nematode, Xiphinema vuittenezi

    International Nuclear Information System (INIS)

    Sávoly, Zoltán; Záray, Gyula

    2014-01-01

    Free-living nematodes, due to their microscopic size and quite complex life processes can be widely applied as biological model organisms to study the effect of soil pollutants. The modern X-ray spectrometric methods enable the individual analysis of microscopic biological samples, hereby expanding the scope of environmental and toxicological sciences. In order to study the uptake and bioaccumulation of Cu and Cr by nematodes (Xiphinema vuittenezi), the worms were starved in tap water for five days, and then treated with solutions of CuSO 4 , Cu(NO 3 ) 2 , KCr(SO 4 ) 2 or K 2 CrO 4 for 1–120 h. The effect of two soil-polluting elements, Cu, which is often applied in herbicides, and Cr, which is essential in the form of Cr(III), but toxic if it occurs as Cr(VI), on soil-inhabiting nematodes was studied. The uptake of these toxicants and their bioaccumulation was investigated by TXRF, following a two-step sample digestion method (digestion with HNO 3 and using cold O plasma). Their effect on the essential element content of nematodes was also studied. Differences were found between the uptake of Cr(III) and Cr(VI). The Cr(III) causes decreased Zn content comparing with untreated nematodes, for Cr(VI) it was not observed. Elemental maps in the cross-sections of the worms prepared by focused gallium ion beam, following a special sample preparation method (quick-freezing in liquid nitrogen for 2 min and lyophilization for 72 h) were collected by scanning electron microscope equipped with energy dispersive X-ray detector. The distribution of Cr-P and Cu-P showed a similar pattern, however, the distribution of S deviated from these ones. According to these findings, the role of P-containing ligands in the binding of Cu and Cr is more characteristic than of S-containing ones. With the purpose of studying the speciation of the Cu and Cr in the worm, X-ray absorption near edge structure spectrometry was applied. The sample preparation method was the same as in the case of

  5. Adsorbent material based on passion-fruit wastes to remove lead (Pb), chromium (Cr) and copper (Cu) from metal-contaminated waters

    Science.gov (United States)

    Campos-Flores, Gaby; Castillo-Herrera, Alberto; Gurreonero-Fernández, Julio; Obeso-Obando, Aída; Díaz-Silva, Valeria; Vejarano, Ricardo

    2018-04-01

    The aim of the present work was to evaluate the feasibility of passion-fruit shell (PFS) biomass as adsorbent material to remove heavy metals from contaminated waters. Model mediums were used, which were composed of distilled water and the respective metal: lead (Pb), chromium (Cr) and copper (Cu), with a dose of 10g of dry PFSbiomass per liter of medium. The residual concentration of each metal was determined by Atomic Absorption Spectrophotometry (AAS). A good adsorption capacity was exhibited by this agro industrial waste, achieving removal levels of 96,93 and 82% for Pb, Cr and Cu, respectively. In addition, the results obtained showed an adequate fit to the Freundlich model (R2 > 0.91), on the basis of which, the following values of adsorption capacity (k: 1.7057, 0.6784, 0.3302) and adsorption intensity (n: 0.6869, 2.3474, 1.0499), for Pb, Cr and Cu respectively, were obtained. Our results suggest that Pb, Cr and Cu ions can be removed by more than 80% by using this agro industrial waste, which with a minimum treatment could be used as an adsorbent material in the treatment of metal-contaminated waters.

  6. Hume-Rothery electron concentration rule across a whole solid solution range in a series of gamma-brasses in Cu-Zn, Cu-Cd, Cu-Al, Cu-Ga, Ni-Zn and Co-Zn alloy systems

    Science.gov (United States)

    Mizutani, U.; Noritake, T.; Ohsuna, T.; Takeuchi, T.

    2010-05-01

    The aim of the present work is to examine if the Hume-Rothery stabilisation mechanism holds across whole solid solution ranges in a series of gamma-brasses with especial attention to the role of vacancies introduced into the large unit cell. The concentration dependence of the number of atoms in the unit cell, N, for gamma-brasses in the Cu-Zn, Cu-Cd, Cu-Al, Cu-Ga, Ni-Zn and Co-Zn alloy systems was determined by measuring the density and lattice constants at room temperature. The number of itinerant electrons in the unit cell, e/uc, is evaluated by taking a product of N and the number of itinerant electrons per atom, e/a, for the transition metal element deduced earlier from the full-potential linearised augmented plane wave (FLAPW)-Fourier analysis. The results are discussed within the rigid-band model using as a host the density of states (DOS) derived earlier from the FLAPW band calculations for the stoichiometric gamma-brasses Cu5Zn8, Cu9Al4 and TM2Zn11 (TM = Co and Ni). A solid solution range of gamma-brasses in Cu-Zn, Cu-Cd, Cu-Al, Cu-Ga and Ni-Zn alloy systems is found to fall inside the existing pseudogap at the Fermi level. This is taken as confirmation of the validity of the Hume-Rothery stability mechanism for a whole solute concentration range of these gamma-brasses. An exception to this behaviour was found in the Co-Zn gamma-brasses, where orbital hybridisation effects are claimed to play a crucial role in stabilisation.

  7. Facile synthesis of spinel CuCr{sub 2}O{sub 4} nanoparticles and studies of their photocatalytic activity in degradation of some selected organic dyes

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Bappi; Bhuyan, Bishal [Department of Chemistry, National Institute of Technology Silchar, Silchar, 788010, Assam (India); Purkayastha, Debraj Dhar, E-mail: debrajdp@yahoo.com [Department of Chemistry, National Institute of Technology Silchar, Silchar, 788010, Assam (India); Dhar, Siddhartha Sankar, E-mail: ssd_iitg@hotmail.com [Department of Chemistry, National Institute of Technology Silchar, Silchar, 788010, Assam (India); Behera, Satyananda [Department of Ceramic Engineering, National Institute of Technology Rourkela, Rourkela, 769008, Odisha (India)

    2015-11-05

    Copper chromite (CuCr{sub 2}O{sub 4}) spinel nanoparticle catalysts have been successfully synthesized employing urea assisted co-precipitation followed by calcination. The synthesized nanoparticles were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and N{sub 2} adsorption-desorption isotherm (BET). The XRD pattern revealed formation of tetragonal body-centered CuCr{sub 2}O{sub 4} and TEM image showed quasi-spherical particles of size 5–35 nm. The photocatalytic activity of CuCr{sub 2}O{sub 4} was evaluated in degradation of some organic dyes such as methylene blue (MB), methyl orange (MO), and rhodamine B (RhB), without and with the assistance of H{sub 2}O{sub 2} under solar irradiation. The CuCr{sub 2}O{sub 4} photocatalysts showed high activity in degradation of RhB (93.6%) and MO (92.3%), but low activity in degradation of MB (80.6%). The catalyst reusability was tested by conducting the degradation of RhB dye with the spent catalyst and it was observed that the catalyst did not show any significant loss in its activity even after five cycles. - Highlights: • CuCr{sub 2}O{sub 4} nanoparticles were synthesized by urea assisted co-precipitation followed by calcination. • The XRD pattern revealed formation of tetragonal body-centered CuCr{sub 2}O{sub 4}. • The TEM images showed the material to be quasi-spherical in shape with sizes 5–35 nm. • CuCr{sub 2}O{sub 4} nanoparticles exhibited pronounced photocatalytic activity.

  8. Microalloying with Cd of Antifriction Sn-Sb-Cu Alloys

    Directory of Open Access Journals (Sweden)

    Cinca Ionel Lupinca

    2012-09-01

    Full Text Available In the case of bimetallic sliding linings with superior technological characteristics, the use of an antifriction ally is imposed an alloy of the type Sn-Sb-Cu, which possesses a high adherence to the steel stand and a high durability in exploitation. For this reason we use the microalloying of the antifriction alloy with cadmium. The microalloying with Cd of antifriction alloys Sn-Sb-Cu determines an increase of the adhesion property of the antifriction alloy on the steel stand. The steel stand is previously subjected to a process of degreasing with ZnCl2 and washing so that is can later be subjected to a thermal-chemical treatment of tinning.

  9. Sol-gel synthesis of Cu-doped p-CdS nanoparticles and their analysis as p-CdS/n-ZnO thin film photodiode

    Science.gov (United States)

    Arya, Sandeep; Sharma, Asha; Singh, Bikram; Riyas, Mohammad; Bandhoria, Pankaj; Aatif, Mohammad; Gupta, Vinay

    2018-05-01

    Copper (Cu) doped p-CdS nanoparticles have been synthesized via sol-gel method. The as-synthesized nanoparticles were successfully characterized and implemented for fabrication of Glass/ITO/n-ZnO/p-CdS/Al thin film photodiode. The fabricated device is tested for small (-1 V to +1 V) bias voltage. Results verified that the junction leakage current within the dark is very small. During reverse bias condition, the maximum amount of photocurrent is obtained under illumination of 100 μW/cm2. Electrical characterizations confirmed that the external quantum efficiency (EQE), gain and responsivity of n-ZnO/p-CdS photodiode show improved photo response than conventional p-type materials for such a small bias voltage. It is therefore revealed that the Cu-doped CdS nanoparticles is an efficient p-type material for fabrication of thin film photo-devices.

  10. Fabrication of low adhesive superhydrophobic surfaces using nano Cu/Al2O3 Ni–Cr composited electro-brush plating

    International Nuclear Information System (INIS)

    Chen, Tianchi; Ge, Shirong; Liu, Hongtao; Sun, Qinghe; Zhu, Wei; Yan, Wei; Qi, Jianwei

    2015-01-01

    Highlights: • We fabricate a low adhesive superhydrophobic nano Cu/Al 2 O 3 composited Ni–Cr coating via brush plating. • We investigate the influence of process parameters on hydrophobic properties process. • We discuss the formation mechanism of structures on the surface and using water rebound height to explain the low adhesive force mechanism. - Abstract: Superhydrophobic nano Cu/Al 2 O 3 Ni–Cr composited coating with a low adhesive force was deposited onto the Q345 carbon steel via electro-brush plating. Surface morphologies of nano Cu/Al 2 O 3 Ni–Cr composited coating were investigated by scanning electron microscope (SEM). Chemical compositions were characterized by energy dispersive spectroscopy (EDS). First of all, by adjusting different process parameters such as working voltage, relative velocity, Cu particles concentration and plating time, we obtain the most optimal parameters: working voltage is 15 V, relative velocity is 4.8 m/min, Cu particles concentration is 5 g/L and plating time is 60 s. Under the best process parameters, the water contact angle reaches to 156° and a sliding angle is less than 2° on the nano Cu/Al 2 O 3 Ni–Cr coating. Then the mechanism of the superhydrophobic and low adhesion characteristic of this surface were explained by Cassie's model. Low adhesive force can be characterized by max rebound height of water droplet. As a result, to achieve low adhesive surface it is necessary to decrease the fraction of the solid/liquid interface under the water droplet. Finally the coating was proved to have an excellent self-cleaning performance.

  11. Effect of Cu(II), Cd(II) and Zn(II) on Pb(II) biosorption by algae Gelidium-derived materials.

    Science.gov (United States)

    Vilar, Vítor J P; Botelho, Cidália M S; Boaventura, Rui A R

    2008-06-15

    Biosorption of Pb(II), Cu(II), Cd(II) and Zn(II) from binary metal solutions onto the algae Gelidium sesquipedale, an algal industrial waste and a waste-based composite material was investigated at pH 5.3, in a batch system. Binary Pb(II)/Cu(II), Pb(II)/Cd(II) and Pb(II)/Zn(II) solutions have been tested. For the same equilibrium concentrations of both metal ions (1 mmol l(-1)), approximately 66, 85 and 86% of the total uptake capacity of the biosorbents is taken by lead ions in the systems Pb(II)/Cu(II), Pb(II)/Cd(II) and Pb(II)/Zn(II), respectively. Two-metal results were fitted to a discrete and a continuous model, showing the inhibition of the primary metal biosorption by the co-cation. The model parameters suggest that Cd(II) and Zn(II) have the same decreasing effect on the Pb(II) uptake capacity. The uptake of Pb(II) was highly sensitive to the presence of Cu(II). From the discrete model it was possible to obtain the Langmuir affinity constant for Pb(II) biosorption. The presence of the co-cations decreases the apparent affinity of Pb(II). The experimental results were successfully fitted by the continuous model, at different pH values, for each biosorbent. The following sequence for the equilibrium affinity constants was found: Pb>Cu>Cd approximately Zn.

  12. Phase relations in the quasi-binary Cu{sub 2}GeS{sub 3}-ZnS and quasi-ternary Cu{sub 2}S-Zn(Cd)S-GeS{sub 2} systems and crystal structure of Cu{sub 2}ZnGeS{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Parasyuk, O.V. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine)]. E-mail: oleg@lab.univer.lutsk.ua; Piskach, L.V. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Romanyuk, Y.E. [Advanced Photonics Laboratory, Institute of Imaging and Applied Optics, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Zaremba, V.I. [Department of Inorganic Chemistry, Ivan Franko National University of Lviv, 6 Kyryla and Mefodiya Str., 79005 L' viv (Ukraine); Pekhnyo, V.I. [V.I. Vernadskii Institute of General and Inorganic Chemistry, Ukrainian National Academy of Sciences, Palladina Ave 32-34, 03680 Kiev (Ukraine)

    2005-07-19

    The isothermal section of the Cu{sub 2}S-Zn(Cd)S-GeS{sub 2} systems at 670K was constructed using X-ray diffraction analysis. At this temperature, two quaternary intermediate phases, Cu{sub 2}CdGeS{sub 4} and {approx}Cu{sub 8}CdGeS{sub 7}, exist in the Cu{sub 2}S-CdS-GeS{sub 2} system, and only one phase, Cu{sub 2}ZnGeS{sub 4}, exists in the Cu{sub 2}S-ZnS-GeS{sub 2} system. The phase diagram of the Cu{sub 2}GeS{sub 3}-ZnS system was constructed using differential-thermal analysis and X-ray diffraction, and the existence of Cu{sub 2}ZnGeS{sub 4} has been confirmed. It forms incongruently at 1359K. Powder X-ray diffraction was used to refine the crystal structure of Cu{sub 2}ZnGeS{sub 4}, which crystallizes in the tetragonal stannite-type structure at 670K (space group I4-bar 2m, a=0.534127(9)nm, c=1.05090(2)nm, R{sub I}=0.0477). The possibility of the formation of quaternary compounds in the quasi-ternary systems A{sup I}{sub 2}X-B{sup II}X-C{sup IV}X{sub 2}, where A{sup I}-Cu, Ag; B{sup II}-Zn, Cd, Hg; C{sup IV}-Si, Ge, Sn and X-S, Se, Te is discussed.

  13. Study of half-metallic ferromagnetism and elastic properties of Cd{sub 1-x}Cr{sub x}Z (Z=S, Se)

    Energy Technology Data Exchange (ETDEWEB)

    Rani, Anita [Guru Nanak College for Girls, Sri Muktsar Sahib, Punjab (India); Kumar, Ranjan [Panjab University Chandigarh, Department of Physics, Chandigarh (India)

    2016-12-15

    We have studied the structural, electronic and magnetic properties of Cd{sub 1-x}Cr{sub x}S and Cd{sub 1-x}Cr{sub x}Se diluted magnetic semiconductors in zinc blende (B3) phase at x = 0.25, 0.125 and 0.0625. The calculations have been performed using DFT (density functional theory) as implemented in SIESTA code using LDA (local density approximation) as exchange-correlation (XC) potential. Study of band structures and DOS (density of states) shows HMF (half-metallic ferromagnetic) nature of Cd{sub 1-x}Cr{sub x}S and Cd{sub 1-x}Cr{sub x}Se alloys. The calculated values of s-d exchange constant Nα and p-d exchange constant Nβ show the magnetic behavior of these compounds. Moreover, both DMSs retain their half-metallic nature at 0.25, 0.125 and 0.0625 concentrations with 100% spin polarization at Fermi level (E{sub F}). Total magnetic moment of these compounds is due to 3d states of Cr atom and also existence of small induced magnetic moment on other non-magnetic atoms as well. HM robustness is also calculated as a function of lattice constants. (orig.)

  14. Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

    African Journals Online (AJOL)

    SERVER

    2008-03-18

    Mar 18, 2008 ... Chemical analysis of the trace elements in the soft tissues. The trace elements of interest (Cu, Zn, Fe, Pb, Cd) were then determined in the digested solutions, using Thermoelemental type. M6 brand of an atomic absorption Spectrometer equipped with a flame operated atomisation system and a deuterium ...

  15. Study of bioaccumulation and biotransformation by microanalytical X-ray techniques: investigation of distribution and speciation of Cu and Cr in the body of the plant-feeding nematode, Xiphinema vuittenezi

    Energy Technology Data Exchange (ETDEWEB)

    Sávoly, Zoltán; Záray, Gyula, E-mail: zaray@ludens.elte.hu

    2014-11-01

    Free-living nematodes, due to their microscopic size and quite complex life processes can be widely applied as biological model organisms to study the effect of soil pollutants. The modern X-ray spectrometric methods enable the individual analysis of microscopic biological samples, hereby expanding the scope of environmental and toxicological sciences. In order to study the uptake and bioaccumulation of Cu and Cr by nematodes (Xiphinema vuittenezi), the worms were starved in tap water for five days, and then treated with solutions of CuSO{sub 4}, Cu(NO{sub 3}){sub 2}, KCr(SO{sub 4}){sub 2} or K{sub 2}CrO{sub 4} for 1–120 h. The effect of two soil-polluting elements, Cu, which is often applied in herbicides, and Cr, which is essential in the form of Cr(III), but toxic if it occurs as Cr(VI), on soil-inhabiting nematodes was studied. The uptake of these toxicants and their bioaccumulation was investigated by TXRF, following a two-step sample digestion method (digestion with HNO{sub 3} and using cold O plasma). Their effect on the essential element content of nematodes was also studied. Differences were found between the uptake of Cr(III) and Cr(VI). The Cr(III) causes decreased Zn content comparing with untreated nematodes, for Cr(VI) it was not observed. Elemental maps in the cross-sections of the worms prepared by focused gallium ion beam, following a special sample preparation method (quick-freezing in liquid nitrogen for 2 min and lyophilization for 72 h) were collected by scanning electron microscope equipped with energy dispersive X-ray detector. The distribution of Cr-P and Cu-P showed a similar pattern, however, the distribution of S deviated from these ones. According to these findings, the role of P-containing ligands in the binding of Cu and Cr is more characteristic than of S-containing ones. With the purpose of studying the speciation of the Cu and Cr in the worm, X-ray absorption near edge structure spectrometry was applied. The sample preparation

  16. Enhanced photovoltaic performance of quantum dot-sensitized solar cells with a progressive reduction of recombination using Cu-doped CdS quantum dots

    International Nuclear Information System (INIS)

    Muthalif, Mohammed Panthakkal Abdul; Lee, Young-Seok; Sunesh, Chozhidakath Damodharan; Kim, Hee-Je; Choe, Youngson

    2017-01-01

    Highlights: • Cu-doped CdS QDs were deposited on TiO_2 by SILAR method. • Cu-doped CdS electrodes contributes reduction of charge recombination and longer electron lifetime. • A promising power conversion efficiency of 3% is obtained for the Cu-doped CdS Quantum dot sensitized solar cell. - Abstract: In this article, we have systematically probed the effect of Cu-doping in CdS quantum dots (QDs) to enhance the photovoltaic performance of the quantum dot-sensitized solar cells (QDSSCs). The Cu-doped CdS photoanodes were prepared by successive ionic layer adsorption and reaction (SILAR) method and the corresponding cell devices were fabricated using CuS counter electrodes with a polysulfide electrolyte. The photovoltaic performance results demonstrate that 3 mM Cu-doped CdS QDs based QDSSCs exhibit the efficiency (η) of 3% including J_S_C = 9.40 mA cm"−"2, V_O_C = 0.637 V, FF = 0.501, which are higher than those with bare CdS (η = 2.05%, J_S_C = 7.12 mA cm"−"2, V_O_C = 0.588 V, FF = 0.489). The structural, topographical and optical properties of the thin films have been studied with the help of X-ray diffraction pattern (XRD), atomic force microscopy (AFM) and UV–vis spectrophotometer. Electrochemical impedance spectroscopy (EIS) and open circuit voltage decay (OCVD) measurements indicate that Cu-dopant can inhibit the charge recombination at the photoanode/electrolyte interface and extend the lifetime of electrons. These results reveal that incorporation of copper metal in CdS QDs is a simple and effective method to improve the photovoltaic properties of QDSSCs.

  17. Enhanced photovoltaic performance of quantum dot-sensitized solar cells with a progressive reduction of recombination using Cu-doped CdS quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Muthalif, Mohammed Panthakkal Abdul [Department of Polymer Science and Chemical Engineering, Pusan National University, Geumjeong-Ku, Jangjeong-Dong, Busan 609-735 (Korea, Republic of); Lee, Young-Seok [School of Electrical Engineering, Pusan National University, Geumjeong-Ku, Jangjeong-Dong, Busan 609-735 (Korea, Republic of); Sunesh, Chozhidakath Damodharan [Department of Polymer Science and Chemical Engineering, Pusan National University, Geumjeong-Ku, Jangjeong-Dong, Busan 609-735 (Korea, Republic of); Kim, Hee-Je [School of Electrical Engineering, Pusan National University, Geumjeong-Ku, Jangjeong-Dong, Busan 609-735 (Korea, Republic of); Choe, Youngson, E-mail: choe@pusan.ac.kr [Department of Polymer Science and Chemical Engineering, Pusan National University, Geumjeong-Ku, Jangjeong-Dong, Busan 609-735 (Korea, Republic of)

    2017-02-28

    Highlights: • Cu-doped CdS QDs were deposited on TiO{sub 2} by SILAR method. • Cu-doped CdS electrodes contributes reduction of charge recombination and longer electron lifetime. • A promising power conversion efficiency of 3% is obtained for the Cu-doped CdS Quantum dot sensitized solar cell. - Abstract: In this article, we have systematically probed the effect of Cu-doping in CdS quantum dots (QDs) to enhance the photovoltaic performance of the quantum dot-sensitized solar cells (QDSSCs). The Cu-doped CdS photoanodes were prepared by successive ionic layer adsorption and reaction (SILAR) method and the corresponding cell devices were fabricated using CuS counter electrodes with a polysulfide electrolyte. The photovoltaic performance results demonstrate that 3 mM Cu-doped CdS QDs based QDSSCs exhibit the efficiency (η) of 3% including J{sub SC} = 9.40 mA cm{sup −2}, V{sub OC} = 0.637 V, FF = 0.501, which are higher than those with bare CdS (η = 2.05%, J{sub SC} = 7.12 mA cm{sup −2}, V{sub OC} = 0.588 V, FF = 0.489). The structural, topographical and optical properties of the thin films have been studied with the help of X-ray diffraction pattern (XRD), atomic force microscopy (AFM) and UV–vis spectrophotometer. Electrochemical impedance spectroscopy (EIS) and open circuit voltage decay (OCVD) measurements indicate that Cu-dopant can inhibit the charge recombination at the photoanode/electrolyte interface and extend the lifetime of electrons. These results reveal that incorporation of copper metal in CdS QDs is a simple and effective method to improve the photovoltaic properties of QDSSCs.

  18. Atmospheric Deposition of Pb, Zn, Cu, and Cd in Amman, Jordan

    International Nuclear Information System (INIS)

    Momani, K.A.; Jiries, A.G.; Jaradat, Q.M.

    1999-01-01

    Atmospheric samples were collected by high-volume air sampler and dust fall containers during the summer of 1995 at different sites in Amman City, Jordan. Heavy metal contents in settle able (dust fall) as well as in air particulates (suspended) were analyzed by graphite furnace atomic absorption spectrophotometry. The atmospheric concentrations of Zn, Cu, Pb, and Cd were 344, 170, 291, and 3.8 ng/m 3 , respectively. On the other hand, the levels of these elements in dust fall deposition were 505, 94, 74, and 3.1 μg/g, respectively. The fluxes and dry deposition velocities of these heavy metals were determined and compared with the findings of other investigators worldwide. Significant enrichment coefficients of heavy metals in dust fall were observed. The enrichment coefficients were 12.1, 6.1, 11.7, and 1.1 for Zn, Cu, Pb, and Cd, respectively

  19. Improved performance of CdSe/CdS co-sensitized solar cells adopting efficient CuS counter electrode modified by PbS film using SILAR method

    Science.gov (United States)

    Zhang, Xiaolong; Lin, Yu; Wu, Jihuai; Fang, Biaopeng; Zeng, Jiali

    2018-04-01

    In this paper, CuS film was deposited onto fluorine-doped tin oxide (FTO) substrate using a facile chemical bath deposition method, and then modified by PbS using simple successive ionic layer absorption and reaction (SILAR) method with different cycles. These CuS/PbS films were utilized as counter electrodes (CEs) for CdSe/CdS co-sensitized solar cells. Field-emission scanning electron microscopy equipped with an energy-dispersive X-ray spectrometer was used to characterize the CuS/PbS films. The results show that CuS/PbS (10 cycles) CE exhibits an improved power conversion efficiency of 5.54% under the illumination of one sun (100 mW cm-2), which is higher than the CuS/PbS (0 cycles), CuS/PbS (5 cycles), and CuS/PbS (15 cycles) CEs. This enhancement is mainly attributed to good catalytic activity and lower charge-transfer and series resistances, which have been proved by electrochemical impedance spectroscopy, and Tafel polarization measurements.

  20. Content of Cr, Cu, Pb, and Zn on Pacific white shrimp cultured in modern farm at BLUPPB, Karawang, West Java

    Science.gov (United States)

    Takarina, N. D.; Rahman, A.; Siswanting, T.; Pin, T. J.

    2018-03-01

    Heavy metal is one of the hazardous substances which often found in shrimp farm. Since this shrimp become mostly favorable food, it is necessary to determine the content of metal in this shrimps. This research was aimed to determine the content of Cr, Cu, Pb, and Zn on Pacific white shrimp cultured on the modern farm at BLUPPB, Karawang, West Java. Samples were taken from five farms. During transport, samples were kept in a more relaxed box. Farms used were designed using black plastic as the bottom layer to separate contact with soil. Heavy metal of Cr, Cu, Pb, and Zn on shrimp meat was analyzed using Atomic Absorption Spectrophotometry method. The content of Cr was ranged from 0.06 – 0.38 ppm and Pb were 0.02 – 0.05 ppm. The content of Cu was ranged from 1.89 – 15.25 ppm and Zn were 2.16 – 3.92 ppm. According to government rules and literature, those content were below a threshold which was 0.4 ppm for Cu, 0.5 ppm for Pb, 20 ppm for Cu and 0.2 ppm for Zn.

  1. An investigation of the evolution of evolution of distribution and accumulation of heavy metals(Cr, Ni, Cu, Cd, Zn and Pb) in Anzali wetland's sediments

    International Nuclear Information System (INIS)

    Sartaj, M.; Fatollahi, F.; Filizadeh, Y.

    2005-01-01

    To investigate the precipitation of heavy metals in Anzali wetland and evaluate its refining performance this study was carried out on the wetland. Monthly samples of sediments from 15 stations including inlets, outlets and some internal locations in the wetland were collected and analyzed over a period of six months (July - December 2002). Sediment samples were analyzed for six metals of Cr, Cd, Pb, Zn, Cu and Ni. Wet digestion method was employed for extraction of metals in samples by and through a solution containing HN03 and HCL. Atomic Adsorption spectrophotometry was employed for measurement of the heavy metals. Statistical methods, including analysis of variance (ANOVA), correlation and Cluster analysis were used for analysis of the data. The results indicated that concentration of heavy metals present in sediments (collected from different stations and at different times) here significantly different. Among the metals studied, Zn was of the highest concentration Heavy metal concentrations in stations 1 1, 12 and 13 were lower than in other stations. Sediments in station 5 contained the highest concentrations of heavy metals among all sediments. It can be stated that concentration of heavy metals decreases with an increase in the distance from delta of rivers entering the wetland.2. This is due to the role and performance of wetland chemical contents in reduction of pollutants, the self-purification action of wetland as well as precipitation of heavy metals at the beginning of the entries into the wetland

  2. Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

    Science.gov (United States)

    Huang, Shih-Yi; Jiang, Shiuh-Jen; Sahayam, A. C.

    2014-11-01

    Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min- 1 methane (CH4) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g- 1 for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g- 1 (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions.

  3. Influence of Cu-Cr substitution on structural, morphological, electrical and magnetic properties of magnesium ferrite

    Directory of Open Access Journals (Sweden)

    S. Yonatan Mulushoa

    2018-03-01

    Full Text Available Cu-Cr substituted magnesium ferrite materials (Mg1 − xCuxCrxFe21 − xO4 with x = 0.0–0.7 have been synthesized by the solid state reaction method. XRD analysis revealed the prepared samples are cubic spinel with single phase face centered cubic. A significant decrease of ∼41.15 nm in particle size is noted in response to the increase in Cu-Cr substitution level. The room temperature resistivity increases gradually from 0.553 × 105 Ω cm (x = 0.0 to 0.105 × 108 Ω cm (x = 0.7. Temperature dependent DC-electrical resistivity of all the samples, exhibits semiconductor like behavior. Cu-Cr doped materials can be suitable to limit the eddy current losses. VSM result shows pure and doped magnesium ferrite particles show soft ferrimagnetic nature at room temperature. The saturation magnetization of the samples decreases initially from 34.5214 emu/g for x = 0.0 to 18.98 emu/g (x = 0.7. Saturation magnetization, remanence and coercivity are decreased with doping, which may be due to the increase in grain size. Keywords: Solid state reaction, X-ray diffraction, Crystallite size, Magnetic and electrical properties, Saturation magnetization

  4. Defects in Cu(InGa)Se2/CdS heterostructure films induced by hydrogen ion implantation

    International Nuclear Information System (INIS)

    Yakushev, M.V.; Tomlinson, R.D.; Hill, A.E.; Pilkington, R.D.; Mudryi, A.V.; Bondar, I.V.; Victorov, I.A.; Gremenok, V.F.; Shakin, I.A.; Patuk, A.I.

    1999-01-01

    The influence of H + ion implantation on the photoluminescence properties of Cu(InGa)Se 2 /CdS heterostructures has been studied. This treatment was found to increase the photoluminescence intensity of donor-acceptor band at 1.13 eV because of the passivation by hydrogen atoms of the non-radiative recombination centers on the boundary of Cu(InGa)Se 2 and CdS layers. Two broad bands peaks at 0.96 eV and at 0.82 eV in photoluminescence spectra of ion-implanted Cu(InGa)Se 2 films have been found. The tentative model to explain the origin of the broad photoluminescence bands has been discussed

  5. Synthesis, macroscopic and local probe characterization of AgCrO$_2$ and CdCr$_2$S$_4$

    CERN Document Server

    Oliveira, Gonçalo; Araujo, J P

    The search of new materials with new and/or enhanced physical properties has, nowadays, a strict relation with the evolution of technology. The hunt for systems exhibiting simultaneous (anti)ferroelectric and (anti)ferromagnetic orders has re-started in the last years, and remains as one of the hot topics for Physic, Chemistry and Materials Science scientific communities. This is triggered by the possibility to apply these materials into, ${e.g.}$, new multiferroic memories that could be written electrically and read magnetically (or vice-versa). This thesis presents an experimental study on two of these so-called multiferroic materials, the AgCrO$_2$ delafossite and CdCr$_2$S$_4$ spinel type compounds. Different methods have been tested for the synthesis of delafossite silver chromium oxide AgCrO$_2$ namely, solid state reaction (ssr) and sol-gel combustion. The processes were optimized regarding complexing/combusting agents, temperature and duration of the heat treatments, as well as the processing atmosphe...

  6. A large enhancement of photoinduced second harmonic generation in CdI2--Cu layered nanocrystals.

    Science.gov (United States)

    Miah, M Idrish

    2009-02-12

    Photoinduced second harmonic generation (PISHG) in undoped as well as in various Cu-doped (0.05-1.2% Cu) CdI2 nanocrystals was measured at liquid nitrogen temperature (LNT). It was found that the PISHG increases with increasing Cu doping up to approximately 0.6% and then decreases almost to that for the undoped CdI2 for doping higher than approximately 1%. The values of the second-order susceptibility ranged from 0.50 to 0.67 pm V(-1) for the Cu-doped nanocrystals with a thickness of 0.5 nm. The Cu-doping dependence shown in a parabolic fashion suggests a crucial role of the Cu agglomerates in the observed effects. The PISHG in crystals with various nanosizes was also measured at LNT. The size dependence demonstrated the quantum-confined effect with a maximum PISHG for 0.5 nm and with a clear increase in the PISHG with decreasing thickness of the nanocrystal. The Raman scattering spectra at different pumping powers were taken for thin nanocrystals, and the phonon modes originating from interlayer phonons were observed in the spectra. The results were discussed within a model of photoinduced electron-phonon anharmonicity.

  7. Bioavailability of Pb, Zn, Cu, Cd, Ni and Cr in the sediments of the Tessa River: A mining area in the North-West Tunisia

    Science.gov (United States)

    Sebei, Abdelaziz; Helali, Mohamed Amine; Oueslati, Walid; Abdelmalek-Babbou, Chiraz; Chaabani, Fredj

    2018-01-01

    Tessa River is seen as one of the important rivers in Tunisia. Its catchment is known for its agricultural and mining activities, especially the Bougrine and Fedj Lahdhoum mines. Eighteen (18) surface sediments and five (5) water samples were collected from the Tessa River, near these two mining sites. Sediments are essentially sandy (>80%), the most important mineral is quartz (20-73%), then calcite (41%) and dolomites (4%). Heavy metal contents are relatively high near the mining sites, 356 μg g-1 for Pb, 3000 μg g-1 for Zn, and 5 μg g-1 for Cd. These values are lower downstream due to watercourse dilution effects. Other heavy metals: Cu, Ni and Cr, are low, and values are relatively constant in all the studied samples, even near the mining sites. The metals originate from natural sources and not from mining activities. This trend is confirmed by the enrichment factor (EF) where EFNi, EFCu and EFCr are lower or equal to 1, unlike EFPb, EFZn or EFCd where values are much higher (>20). Chemical speciation of these metals does not show any spatial variation. Except for cadmium which is bound to the residual fraction and in the carbonates; all other heavy metals are bound to the five sediment chemical fractions: the residual fraction (>52%), followed by the oxyhydroxides fraction (21%) and carbonates (16%), and finally bound to the organic matter and to the exchangeable fraction (bioavailable fraction of the studied heavy metals exceeds 45%, which present risk of toxicity.

  8. Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Shih-Yi [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Jiang, Shiuh-Jen, E-mail: sjjiang@faculty.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Sahayam, A.C. [National Centre for Compositional Characterisation of Materials (CCCM), Hyderabad (India)

    2014-11-01

    Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min{sup −1} methane (CH{sub 4}) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g{sup −1} for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g{sup −1} (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions. - Highlights: • Determination of Cr, Fe, Cu, Zn and Se in cereal samples • Ultrasonic slurry sampling in combination with DRC-ICP-MS • Better sensitivity with thioacetamide modifier in ETV • Decreased sample preparation time with solid sampling • Validation with NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour.

  9. Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

    International Nuclear Information System (INIS)

    Huang, Shih-Yi; Jiang, Shiuh-Jen; Sahayam, A.C.

    2014-01-01

    Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min −1 methane (CH 4 ) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g −1 for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g −1 (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions. - Highlights: • Determination of Cr, Fe, Cu, Zn and Se in cereal samples • Ultrasonic slurry sampling in combination with DRC-ICP-MS • Better sensitivity with thioacetamide modifier in ETV • Decreased sample preparation time with solid sampling • Validation with NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour

  10. Heavy metal (Cu, Cr, Zn, and Fe) concentration on coralreef in panjang island coastal, Jepara

    International Nuclear Information System (INIS)

    Heni Susiati; Yarianto SBS; Ali Arman L; Yulizon Menri

    2008-01-01

    Observation on the accumulation of Cu, Cr, Zn, and Fe heavy metals in coral tissue were carried out in Panjang island, Jepara by NAA method. The purpose of this research is to determine the concentration of heavy metals on coral reef tissue in order to update environmental data to support site licensing and Environmental Impact Assessment (EIA) of Nuclear Power Plants (NPP). The result indicated that the concentration of Zn is 1,78 - 42,34 ppm, Cu is undetected - 0,41 ppm, Cr is 0,03 - 0,35 ppm and Fe is 5,25 - 30,56 ppm. The data shows that the accumulation of heavy metals in the coral reef tissue is higher than environmental threshold value, especially for marine biota life referring to the Environmental Ministry Decree Number 51 year 2004. (author)

  11. Implications of orbital hybridization on the electronic properties of doped quantum dots: the case of Cu:CdSe

    Science.gov (United States)

    Wright, Joshua T.; Forsythe, Kyle; Hutchins, Jamie; Meulenberg, Robert W.

    2016-04-01

    This paper investigates how chemical dopants affect the electronic properties of CdSe quantum dots (QDs) and why a model that incorporates the concepts of orbital hybridization must be used to understand these properties. Extended X-ray absorption fine structure spectroscopy measurements show that copper dopants in CdSe QDs occur primarily through a statistical doping mechanism. Ultraviolet photoemission spectroscopy (UPS) experiments provide a detailed insight on the valence band (VB) structure of doped and undoped QDs. Using UPS measurements, we are able to observe photoemission from the Cu d-levels above VB maximum of the QDs which allows a complete picture of the energy band landscape of these materials. This information provides insights into many of the physical properties of doped QDs, including the highly debated near-infrared photoluminescence in Cu doped CdSe QDs. We show that all our results point to a common theme of orbital hybridization in Cu doped CdSe QDs which leads to optically and electronically active states below the conduction band minimum. Our model is supported from current-voltage measurements of doped and undoped materials, which exhibit Schottky to Ohmic behavior with Cu doping, suggestive of a tuning of the lowest energy states near the Fermi level.This paper investigates how chemical dopants affect the electronic properties of CdSe quantum dots (QDs) and why a model that incorporates the concepts of orbital hybridization must be used to understand these properties. Extended X-ray absorption fine structure spectroscopy measurements show that copper dopants in CdSe QDs occur primarily through a statistical doping mechanism. Ultraviolet photoemission spectroscopy (UPS) experiments provide a detailed insight on the valence band (VB) structure of doped and undoped QDs. Using UPS measurements, we are able to observe photoemission from the Cu d-levels above VB maximum of the QDs which allows a complete picture of the energy band landscape of

  12. Determination of Cd, Pb and Cu in Mandovi estuary by differential pulse anodic stripping voltammetry

    Digital Repository Service at National Institute of Oceanography (India)

    George, M.D.; Sawkar, K.; Reddy, C.V.G.

    Dissolved labile and non-labile (organically associated) concentration of Cd, Pb and Cu in Mandovi Estuary, Goa, India have been measured for 1 y (February 1980 to January 1981). Percentage non-labile form varies from 0-50% of the total for Cd, from...

  13. Modeling Cd and Cu mobility in soils amended by long-term urban waste compost applications

    Science.gov (United States)

    Filipović, Vilim; Cambier, Philippe; Matijević, Lana; Coquet, Yves; Pot, Valérie; Houot, Sabine; Benoit, Pierre

    2016-04-01

    Urban waste compost application to soil is an effective way for organic waste disposal and at the same time may have a positive effect on various soil rhizosphere processes. However, long term applications of organic waste amendments may lead to a noteworthy accumulation of micropollutants in soil. The long-term field experiment QualiAgro, an INRA-Veolia partnership (https://www6.inra.fr/qualiagro_eng/), has been conducted since 1998 with the objectives to characterize the agronomic value of urban composts and the environmental impacts of their application. Numerical modeling was performed using HYDRUS-2D to estimate the movement of Cd and Cu from compost incroporation in the tilled layer. Experimental plots regularly amended with co-compost of sewage sludge and green wastes (SGW), or a municipal solid waste compost (MSW) have been compared to control plot without any organic amendment (CONT). Field site was equipped with wicks lysimeters, TDR probes and tensiometers in order to determine water balance and trace metal concentrations during a 6 years' time period (2004-2010). In the tilled layer different structures (Δ - compacted clods, Γ - macroporous zone, IF - interfurrows, PP - plough pan) corresponding to the tillage and compost incorporation were delimited and reproduced in a 2-D model. The increase of Cd and Cu concentrations due to each compost addition was assumed to be located in IFs for further modeling. Four compost additions were performed during 2004-2010 period which increased the Cd and Cu concentrations in the IF zones considerably. After successful model description of water flow in highly heterogeneous soil profiles, Cd and Cu were added into the model and their fate was simulated during the same time period. Two approaches were followed to estimate plausible trace metals sorption coefficients (Kd), both while assuming equilibrium between dissolved and EDTA-extractable metals. The first approach was based on Kd estimated from ratios between

  14. Metal (Cu, Cd and Zn) removal and stabilization during multiple soil washing by saponin.

    Science.gov (United States)

    Gusiatin, Zygmunt Mariusz; Klimiuk, Ewa

    2012-01-01

    The influence of multiple saponin washing on copper, cadmium and zinc removal and stability in three types of soils (loamy sand, loam, silty clay) was investigated. Distribution of metals and their mobility measured as the ratio of exchangeable form to the sum of all fractions in soils was differential. After single washing the highest efficiency of metal removal was obtained in loamy sand (82-90%) and loam (67-88%), whereas the lowest in silty clay (39-62%). In loamy sand and loam metals had higher mobility factors (44-61% Cu, 60-76% Cd, and 68-84% Zn) compared to silty clay (9% Cu, 28% Cd and 36% Zn). Triplicate washing led to increase both efficiency of metal removal and percentage content of their stable forms. In consequence, fractional patterns for metals before and after treatment changed visibly as a result of their redistribution. Based on the redistribution index, the most stable metal (mainly in residual and organic fractions) after triplicate washing was Cu in loamy sand and loam. For silty clay contaminated with Cd, effective metal removal and its stabilization required a higher number of washings. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Certification of trace element contents (As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb and Zn) in a fly ash obtained from the combustion of pulverised coal

    International Nuclear Information System (INIS)

    Griepink, B.; Colinet, E.; Guzzi, G.; Haemers, L.; Muntau, H.

    1983-01-01

    The element contents of As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb and Zn of a fly ash from pulverised coal are certified. The procedures and their results for the homogenisation, the contamination and homogeneity checks and the analytical campaign are reported. The certified mass fractions and indicative values for Cr, Ni, Th, V and water soluble sulphate are given. The work was carried out within the framework of the activities of the Community Bureau of Reference (BCR) of the Commission of the European Communities. (orig.) [de

  16. Determination of Cu, Cr, and As in preserved wood (Eucalyptus sp.) using x-ray fluorescent spectrometry techniques

    International Nuclear Information System (INIS)

    Sergio Matias Pereira Junior; Vera Akiko Maihara; Edson Goncalves Moreira; Vera Lucia Ribeiro Salvador; Ivone Mulako Sato

    2016-01-01

    Energy dispersive (EDXRF) and Portable (PXRF) X-ray fluorescence techniques are proposed for wood treatment control process and wood waste assortment. In this study, different retentions of chromated copper arsenate preservative were applied to Eucalyptus sp. sapwood samples. Cu, Cr and As were determined by XRF techniques in treated sapwood massive blocks and treated sapwood sawdust samples were analyzed by FAAS spectrometry (Flame Atomic Absorption) and INAA (Instrumental Neutron Activation Analysis). Cu, Cr and As mean values, obtained by FAASS and INAA, showed to be statically equal; however, XRF analysis showed considerable deviations, presenting the absorption and the enhancement effects in analytical lines. (author)

  17. Mechanical alloying of Cu-xCr (x = 3, 5 and 8 wt.%) alloys

    International Nuclear Information System (INIS)

    Aguilar, C.; Ordonez, S.; Guzman, D.; Rojas, P.A.

    2010-01-01

    This work studies the structural evolution of Cu-xCr (x = 3, 5 and 8 wt.%) alloys processed by mechanical alloying using X-ray diffraction profiles, scanning microscopy and microhardness analysis. X-ray diffraction analysis using the modified Williamson-Hall and Warren-Averbach methods were used to determine structural properties, such as crystallite size, stacking fault probability and energy, dislocation density, lattice parameters and crystallite size distribution of metallic powder as a function of Cr amount and milling time. Lattice defects increase the Gibbs free energy and the Gibbs free energy curves shift upward, therefore the solubility limit change.

  18. Graphite furnace analysis of a series of metals (Cu, Mn, Pb, Zn and Cd) in ox kidney

    International Nuclear Information System (INIS)

    Souza, Vivianne L.B. de; Nascimento, Rizia K. do; Paiva, Ana Claudia de; Silva, Josenilda M. da; Melo, Jessica V. de

    2013-01-01

    The aim of this study was to create a methodology for animal tissue analysis, with the use of flame atomic absorption spectrophotometry techniques and graphite furnace analysis to determining metal concentrations in ox kidney. The organ of this animal can be considered a great nutritional food, due to the high protein and micronutrient content beyond the ability to absorb and concentrate important metals such as Zn, Fe, Mn and Se. On the other hand, there is a risk when eating this food owing to the capacity to accumulate toxic metals such as Pb and Cd. In accordance with the laboratory analysis, Zn can be analyzed by flame atomic absorption spectrophotometry, but other metals such as Cu, Mn, Pb and Cd, could only be detected by graphite furnace analysis. The results showed that there is more Zn and Cu than other metals. Such metals follows an order reported by the literature (Zn > Cu > Cd > Pb > Mn). The results showed that kidney is actually a rich source of Zn and Cu. The Cd levels in the ox kidney did not exceed the values which cause toxic effects. The adequacy of the results indicates that the proposed methodology can be used for animal tissue analysis.(author)

  19. Graphite furnace analysis of a series of metals (Cu, Mn, Pb, Zn and Cd) in ox kidney

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Vivianne L.B. de; Nascimento, Rizia K. do; Paiva, Ana Claudia de; Silva, Josenilda M. da, E-mail: vlsouza@cnen.gov.br, E-mail: riziakelia@hotmail.com, E-mail: acpaiva@cnen.gov.br, E-mail: jmnilda@hotmail.com [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Melo, Jessica V. de, E-mail: Jessica_clorofila@hotmail.com [Universidade de Pernambuco, Recife, PE (Brazil)

    2013-07-01

    The aim of this study was to create a methodology for animal tissue analysis, with the use of flame atomic absorption spectrophotometry techniques and graphite furnace analysis to determining metal concentrations in ox kidney. The organ of this animal can be considered a great nutritional food, due to the high protein and micronutrient content beyond the ability to absorb and concentrate important metals such as Zn, Fe, Mn and Se. On the other hand, there is a risk when eating this food owing to the capacity to accumulate toxic metals such as Pb and Cd. In accordance with the laboratory analysis, Zn can be analyzed by flame atomic absorption spectrophotometry, but other metals such as Cu, Mn, Pb and Cd, could only be detected by graphite furnace analysis. The results showed that there is more Zn and Cu than other metals. Such metals follows an order reported by the literature (Zn > Cu > Cd > Pb > Mn). The results showed that kidney is actually a rich source of Zn and Cu. The Cd levels in the ox kidney did not exceed the values which cause toxic effects. The adequacy of the results indicates that the proposed methodology can be used for animal tissue analysis.(author)

  20. Matrix-Assisted Laser Desorption Ionization Mass Spectrometry of Compounds Containing Carboxyl Groups Using CdTe and CuO Nanoparticles

    OpenAIRE

    Megumi Sakurai; Taro Sato; Jiawei Xu; Soichi Sato; Tatsuya Fujino

    2018-01-01

    Matrix-assisted laser desorption ionization mass spectrometry of compounds containing carboxyl groups was carried out by using semiconductor nanoparticles (CdTe and CuO) as the matrix. Salicylic acid (Sal), glucuronic acid (Glu), ibuprofen (Ibu), and tyrosine (Tyr) were ionized as deprotonated species (carboxylate anions) by using electrons ejected from CdTe after the photoexcitation. When CuO was used as the matrix, the peak intensity of Tyr became high compared with that obtained with CdTe....

  1. Nitric oxide overcomes Cd and Cu toxicity in in vitro-grown tobacco plants through increasing contents and activities of rubisco and rubisco activase.

    Science.gov (United States)

    Khairy, Alaaldin Idris H; Oh, Mi Jeong; Lee, Seung Min; Kim, Da Som; Roh, Kwang Soo

    2016-06-01

    Toxic heavy metals such as cadmium (Cd) and copper (Cu) are global problems that are a growing threat to the environment. Despite some heavy metals are required for plant growth and development, others are considered toxic elements and do not play any known physiological role in plant cells. Elevated doses of Cd or Cu cause toxicity in plants and generate damages due to the stress condition and eventually cause a significant reduction in quantity and quality of crop plants. The nitric oxide (NO) donor sodium nitroprusside (SNP) is reported to alleviate the toxicity of some heavy metals like Cd and Cu. In the current study, the role of NO in alleviating stresses of Cd and Cu was investigated in in vitro -grown tobacco ( Nicotiana tabacum ) Based on plant growth, total chlorophyll contents, contents and activities of rubisco and rubisco activase. According to the results of this study, the growth and total chlorophyll contents of Cd/Cu stressed plants were hugely decreased in the absence of SNP, while the supplementation of SNP resulted in a significant increase of both fresh weight and total chlorophyll contents. Remarkable reductions of Rubisco and rubisco activase contents and activities were observed in Cd and Cu-induced plants. SNP supplementation showed the highest contents and activities of rubisco and rubisco activase compared to the control and Cu/Cd-stressed plants. Taken together, our findings suggest that SNP could play a protective role in regulation of plant responses to abiotic stresses such as Cd and Cu by enhancing Rubisco and Rubisco activase.

  2. Bioaccumulation of heavy metals and metalloids in luffa (luffa cylindrica l.) irrigated with domestic wastewater in jhang, pakistan: a prospect for human nutrition

    International Nuclear Information System (INIS)

    Khani, Z.I.; Ahmad, K.

    2015-01-01

    In the present study, 12 heavy metals (Cr, Mn, Ni, Cd, Co, Cu, Pb, Zn, Fe, Se, As, and Mo) were assessed in a potential vegetable Luffa cylindrica. The vegetable was collected randomly from two different sites located at Jhang, Punjab Pakistan. The analyses of variance of data collected from soil showed non-significant effect on Se, Zn, As, Cr, Ni, Mo and Pb while significant effect on Fe, Co, Mn, Cu and Cd metals. Concentrations of all 12 heavy metals in the soil samples were low at sampling site-I as compared to those at site-II except Ni. These concentrations were found below the safe limits except that of Cd. At site-I, the concentrations recorded for different heavy metals were: As > Fe > Pb > Mn > Cd > Co > Cu > Mo > Zn > Ni > Se > Cr while at site-II were: As > Fe > Mn > Pb > Co > Cd > Cu > Mo > Zn > Ni > Se > Cr. Enrichment co-efficient of Cr was higher which showed that root of luffa plant accumulated more Cr concentration from the contaminated soil. The order of enrichment co-efficient was recorded at site-I as: Cr > Zn > Mn > Cu > Fe > Ni > Mo > Pb > As > Se > Co > Cd, and at site-II Cr > Zn > Mn > Ni > Cu > Fe > Mo > Pb > Se > As > Co > Cd. The transfer co-efficient of Mn was higher which indicates that more contents of Mn were transferred from roots to upper edible part. The order of transfer co-efficient at site-I was: Ni > Se > Mo > Cr > Zn > Fe > Mn > Cd > Pb > As > Cu > Co and at site-II was Mn > Zn > As > Fe > Pb > Se > Cd > Co > Mo > Cu > Ni > Cr. Correlation analysis showed that Mn, Se, Co, Cd, Ni, Mo and Pb had positive non-significant correlation, whereas a negative and non-significant correlation for Zn, As, Fe and Cr. The order of pollution load index at site-I was Cd > Mo > Se > Pb > Cu > Co > As > Fe > Mn > Ni > Zn > Cr and at site-II: Cd > Mo > Se > Pb > Cu > Co > As > Fe > Mn > Ni > Zn > Cr. Overall, at both sites, lowest concentration of Cr and highest of As were observed which need substantial awareness. Health risk index depends on

  3. Magnetic properties of CuFe{sub 1−x}Cr{sub x}O{sub 2} nanoparticles surrounded by amorphous SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mori, K.; Hachisu, M.; Yamazaki, T.; Ichiyanagi, Y., E-mail: yuko@ynu.ac.jp [Department of Physics, Graduate School of Engineering, Yokohama National University, Yokohama 240-8501 (Japan)

    2015-05-07

    CuFe{sub 1−x}Cr{sub x}O{sub 2} (0 ≤ x ≤ 1.0) nanoparticles surrounded by amorphous SiO{sub 2} with an average diameter of 30–50 nm were synthesized using a wet chemical method. The annealing temperatures were controlled to yield various sizes of single-phase CuFe{sub 1−x}Cr{sub x}O{sub 2} nanoparticles. CuFeO{sub 2} bulk crystal is known to have a multiferroic delafossite structure with two Néel temperatures of 11 and 14 K; however, the transition temperature shifted higher as the Cr–ion doping level increased. In addition, the lattice constants decreased in accordance with increased Cr-ion doping, which was confirmed by X-ray diffraction measurements. The magnetization curves showed weak ferromagnetic behavior and no coercivity was observed. Hence, frustration in the triangular lattice of the delafossite structure can be released by Cr–ion doping and higher magnetization can be expected. A fine structure analysis through X-ray absorption fine structure measurements was also conducted. It was found that the structure of the Cu ion is similar to that of Cu{sub 2}O, and the c axis of the CuFe{sub 1−x}Cr{sub x}O{sub 2} should be shortened by the Cr–ion doping.

  4. New antiferromagnetic semiconductor CuCr1.5Sb0.5S4

    International Nuclear Information System (INIS)

    Kesler, Ya.A.; Koroleva, L.I.; Mikheev, M.G.; Odintsov, A.G.; Filimonov, D.S.

    1993-01-01

    New halcogenide compound with spinel-antiferromagnetic semiconductor CuCr 1.5 Sb 0.5 S 4 are obtained and studied for the first time. Magnetic properties of this compound, namely, magnetization linear dependence, maximum on PHI(T) curve in the low-temperature area and realization of the Curie-Weis law for paramagnetic susceptibility with negative paramagnetic temperature testiby to the fact that this compound is antiferromagnetic

  5. Effect of the competition of Cu(II) and Ni(II) on the kinetic and thermodynamic stabilities of Cr(III)-organic ligand complexes using competitive ligand exchange (EDTA).

    Science.gov (United States)

    Cunha, Graziele da Costa; Goveia, Danielle; Romão, Luciane Pimenta Cruz; de Oliveira, Luciana Camargo

    2015-05-01

    The effect of competition of Cu(II) and Ni(II) on the kinetic stability of Cr(III) complexed with natural organic matter (NOM) was characterized using EDTA exchange with single-stage tangential-flow ultrafiltration. For a water sample from Serra de Itabaiana, 3% of spiked Cr(III) was exchanged, while for a sample from the Itapanhaú River, 7, 10, 10, and 21% was exchanged in experiments using Cr(III) alone and in combination with Cu(II), Ni(II), or Cu(II) + Ni(II), respectively. Times required to reach exchange equilibrium with EDTA were less than 360 min. The influence of competition from Ni(II) and Cu(II) on the availability of complexed Cr(III) was low, demonstrating preference of the ligand sites for Cr(III). This was correlated with sample humification, as confirmed by EPR and (13)C NMR analyses. Exchange efficiency was in the order Cu > Ni > Cr, and the process could be readily described by first order kinetics, with average rate constants of 0.35-0.37 h(-1). Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Microstructural evolution of direct chill cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy during solution treatment

    Directory of Open Access Journals (Sweden)

    He Kezhun

    2011-08-01

    Full Text Available Heat treatment has important influence on the microstructure and mechanical properties of Al-Si alloys. The most common used heat treatment method for these alloys is solution treatment followed by age-hardening. This paper investigates the microstructural evolution of a direct chill (DC cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy after solution treated at 500, 510, 520 and 530℃, respectively for different times. The major phases observed in the as-cast alloy are α-aluminum dendrite, primary Si particle, eutectic Si, Al7Cu4Ni, Al5Cu2Mg8Si6, Al15(Cr, Fe, Ni, Cu4Si2 and Al2Cu. The Al2Cu phase dissolves completely after being solution treated for 2 h at 500℃, while the eutectic Si, Al5Cu2Mg8Si6 and Al15(Cr, Fe, Ni, Cu4Si2 phases are insoluble. In addition, the Al7Cu4Ni phase is substituted by the Al3CuNi phase. The α-aluminum dendrite network disappears when the solution temperature is increased to 530℃. Incipient melting of the Al2Cu-rich eutectic mixture occurrs at 520℃, and melting of the Al5Cu2Mg8Si6 and Al3CuNi phases is observed at a solution temperature of 530℃. The void formation of the structure and deterioration of the mechanical properties are found in samples solution treated at 530℃.

  7. The elements distribution of Fe, Cd, Ca, Co and Cr on the well water and river in area Wonosari Gunung Kidul

    International Nuclear Information System (INIS)

    Rosidi; Agus Taftazani; Sukirno

    2010-01-01

    The analysis of Fe, Cd, Ca, Co and Cr on the well water and river were detected by γ spectrometer with HPGe detector using NAA method. The main objective of this research was carried out to characterize the Fe, Cd, Ca, Co and Cr on the well water and river in area Gunung Kidul Yogyakarta, which accommodate of the present of environment data in support the clean water program. The result indicated that concentration of elements in well and river water at the Wonosari were still in standard level by Govenor of Daerah Istimewa Yogyakarta no 214/KPTS/1991, were Cd = 0,005 mg/L; Ca = 200 mg/L; Fe = 0,5 mg/L; Co = 0,2 mg/L and Cr = 0,050 mg/L. The concentration in water of Cd, Fe, Ca, Co, and Cr were (0.0002-0.006), (16-40), (5-20), (0.0002-0.37) and (0.0003-0.005) mg/L respectively. The result of analysis give the information that these elements concentration were still proper to use for domestic activities. (author)

  8. Influence of TiO2 particle size and conductivity of the CuCrO2 ...

    Indian Academy of Sciences (India)

    2017-11-28

    Nov 28, 2017 ... Solid-state dye-sensitized solar cells; sol–gel method; TiO2 nanoparticle; CuCrO2 nanoparticles; electrical ... The purpose of this work is construction and optimization .... can be attributed to the electron transport mechanism.

  9. Pb, Cu and Cd distribution in five estuary systems of Marche, central Italy.

    Science.gov (United States)

    Annibaldi, Anna; Illuminati, Silvia; Truzzi, Cristina; Libani, Giulia; Scarponi, Giuseppe

    2015-07-15

    Heavy metals are subjected to monitoring in estuarine and marine water by the European Union Water Framework Directive, which requires water body health to be achieved by 2021. This is the first survey of heavy metals content in five estuaries of Marche, a region in central Italy. Results showed that total Pb and Cu concentrations decreased by 70-80%, from 1000-2000 to 100-200 ng L(-1) (Pb) and from 2000-3000 to 500-1000 ng L(-1) (Cu) from river to sea. Cd was consistently 20-40 ng L(-1). Dissolved Pb and Cu concentrations declined by 50% and 70% respectively passing from oligohaline to euhaline water, from 150 to 70 ng L(-1) and from 2000-1000 to 600-400 ng L(-1). Cd decreased slightly from ∼20 to ∼10 ng L(-1). Although such concentrations are in the range allowed by the Water Framework Directive, they far exceed (up to 10×) the ground content ceiling set for 2021. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Effect of Post Treatment For Cu-Cr Source/Drain Electrodes on a-IGZO TFTs

    OpenAIRE

    Hu, Shiben; Fang, Zhiqiang; Ning, Honglong; Tao, Ruiqiang; Liu, Xianzhe; Zeng, Yong; Yao, Rihui; Huang, Fuxiang; Li, Zhengcao; Xu, Miao; Wang, Lei; Lan, Linfeng; Peng, Junbiao

    2016-01-01

    We report a high-performance amorphous Indium-Gallium-Zinc-Oxide (a-IGZO) thin-film transistor (TFT) with new copper-chromium (Cu-Cr) alloy source/drain electrodes. The TFT shows a high mobility of 39.4 cm 2 ?V ? 1 ?s ? 1 a turn-on voltage of ?0.8 V and a low subthreshold swing of 0.47 V/decade. Cu diffusion is suppressed because pre-annealing can protect a-IGZO from damage during the electrode sputtering and reduce the copper diffusion paths by making film denser. Due to the interaction of C...

  11. Simultaneous cloud point extraction of low levels of Cd, Cr and Hg in ...

    African Journals Online (AJOL)

    A one-step preconcentration cloud point extraction (CPE) method has been developed for the simultaneous determination of Cd, Cr, and Hg using a mixture of 1-(2-pyridylazo)-2-naphthol (PAN) and 1-(2-thiazolylazo)-2-naphthol (TAN) chelating agents and polyoxyethylene nonylphenylether-20 (PONPE-20) surfactant.

  12. Spectroscopy of Deep Traps in Cu2S-CdS Junction Structures

    Directory of Open Access Journals (Sweden)

    Eugenijus Gaubas

    2012-12-01

    Full Text Available Cu2S-CdS junctions of the polycrystalline material layers have been examined by combining the capacitance deep level transient spectroscopy technique together with white LED light additional illumination (C-DLTS-WL and the photo-ionization spectroscopy (PIS implemented by the photocurrent probing. Three types of junction structures, separated by using the barrier capacitance characteristics of the junctions and correlated with XRD distinguished precipitates of the polycrystalline layers, exhibit different deep trap spectra within CdS substrates.

  13. Effects of hydrazine on the solvothermal synthesis of Cu2ZnSnSe4 and Cu2CdSnSe4 nanocrystals for particle-based deposition of films

    International Nuclear Information System (INIS)

    Chiang, Ming-Hung; Fu, Yaw-Shyan; Shih, Cheng-Hung; Kuo, Chun-Cheng; Guo, Tzung-Fang; Lin, Wen-Tai

    2013-01-01

    The effects of hydrazine on the synthesis of Cu 2 ZnSnSe 4 (CZTSe) and Cu 2 CdSnSe 4 (CCTSe) nanocrystals in an autoclave as a function of temperature and time were explored. On heating at 190 °C for 24-72 h, pure CZTSe and CCTSe nanocrystals could readily grow in the hydrazine-added solution, while in the hydrazine-free solution the intermediate phases such as ZnSe, Cu 2 Se, and Cu 2 SnSe 3 , and Cu 2 SnSe 3 and CdSe associated with the CZTSe and CCTSe nanocrystals grew, respectively. This result reveals that hydrazine can speed up the synthesis of pure CZTSe and CCTSe nanocrystals via a solvothermal process. The mechanisms for the hydrazine-enhanced growth of CZTSe and CCTSe nanocrystals were discussed. The pure CZTSe and CCTSe nanocrystals were subsequently fabricated to the smooth films by spin coating without further annealing in selenium atmosphere. This processing may be beneficial to the fabrication of the absorber layer for solar cells and thermoelectric devices. - Highlights: • Hydrazine enhances the growth of pure Cu 2 ZnSnSe 4 and Cu 2 CdSnSe 4 nanocrystals. • The nanocrystals can be fabricated to films by spin coating without annealing. • This solvothermal processing is promising for the fabrication of thin film devices

  14. The influence of post-processing on creep and microstructure of rolled Cu-8Cr-4Nb

    Energy Technology Data Exchange (ETDEWEB)

    Walley, J.L.; Heelan, J.L.; Vettraino, L.G.; Groza, J.R. [Department of Chemical Engineering and Materials Science, University of California, One Shields Ave., Davis, CA 95616 (United States); Gibeling, J.C., E-mail: jcgibeling@ucdavis.edu [Department of Chemical Engineering and Materials Science, University of California, One Shields Ave., Davis, CA 95616 (United States)

    2010-10-15

    Research highlights: {yields} A simulated-life heat treatment anneal of 24 h at 773 K reduced the steady-state creep rate and increased the creep life of a rolled powder metallurgy Cu-8Cr-4Nb alloy. {yields} The primary microstructural difference between the rolled form and the annealed form of Cu-8Cr-4Nb is the development of annealing twins during heat treatment causing a decrease in the intensity of the texture. {yields} Friction stir welding of rolled Cu-8Cr-4Nb negatively affected creep ductility, thereby decreasing creep life at the temperature tested. Strain localization in the soft heat-affected zone of the weld is hypothesized to be the cause of the decreased creep ductility. - Abstract: Previous work has shown that rolling of an extruded Cu-8Cr-4Nb (GRCop-84) alloy results in higher steady-state creep rates over a range of stresses, leading to concern that other post-processing methods could have substantial deleterious effects on creep properties. To explore that possibility, constant-stress creep tests were conducted at 773 K on rolled GRCop-84 after it was subjected to either friction stir welding (FSW) or a 24 h 1073 K simulated-life heat treatment. The FSW had no measurable effect on the creep rate of the rolled material, but did have detrimental effects on the creep ductility caused by softening, and thus strain localization, in the heat-affected zone of the weld. The simulated-life heat treatment decreased the steady-state creep rate by approximately 45% as compared to the rolled material, leading to longer creep life at a particular applied stress. Electron backscatter diffraction methods were used to compare the microstructural features of extruded, rolled and annealed material forms. It was determined that the rolling procedure decreased the grain size, and decreased the intensity of the texture as compared to the extruded form. The simulated-life heat treatment allowed for the substantial development of twins along with minor grain growth, and

  15. The influence of post-processing on creep and microstructure of rolled Cu-8Cr-4Nb

    International Nuclear Information System (INIS)

    Walley, J.L.; Heelan, J.L.; Vettraino, L.G.; Groza, J.R.; Gibeling, J.C.

    2010-01-01

    Research highlights: → A simulated-life heat treatment anneal of 24 h at 773 K reduced the steady-state creep rate and increased the creep life of a rolled powder metallurgy Cu-8Cr-4Nb alloy. → The primary microstructural difference between the rolled form and the annealed form of Cu-8Cr-4Nb is the development of annealing twins during heat treatment causing a decrease in the intensity of the texture. → Friction stir welding of rolled Cu-8Cr-4Nb negatively affected creep ductility, thereby decreasing creep life at the temperature tested. Strain localization in the soft heat-affected zone of the weld is hypothesized to be the cause of the decreased creep ductility. - Abstract: Previous work has shown that rolling of an extruded Cu-8Cr-4Nb (GRCop-84) alloy results in higher steady-state creep rates over a range of stresses, leading to concern that other post-processing methods could have substantial deleterious effects on creep properties. To explore that possibility, constant-stress creep tests were conducted at 773 K on rolled GRCop-84 after it was subjected to either friction stir welding (FSW) or a 24 h 1073 K simulated-life heat treatment. The FSW had no measurable effect on the creep rate of the rolled material, but did have detrimental effects on the creep ductility caused by softening, and thus strain localization, in the heat-affected zone of the weld. The simulated-life heat treatment decreased the steady-state creep rate by approximately 45% as compared to the rolled material, leading to longer creep life at a particular applied stress. Electron backscatter diffraction methods were used to compare the microstructural features of extruded, rolled and annealed material forms. It was determined that the rolling procedure decreased the grain size, and decreased the intensity of the texture as compared to the extruded form. The simulated-life heat treatment allowed for the substantial development of twins along with minor grain growth, and a substantial

  16. Fabrication of low adhesive superhydrophobic surfaces using nano Cu/Al{sub 2}O{sub 3} Ni–Cr composited electro-brush plating

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Tianchi [College of Mechanical & Electrical Engineering, Xu Zhou 221116 (China); Ge, Shirong [College of Mechanical & Electrical Engineering, Xu Zhou 221116 (China); College of Materials Science and Engineering, China University of Mining and Technology, Xu Zhou 221116 (China); Liu, Hongtao, E-mail: liuht100@126.com [College of Materials Science and Engineering, China University of Mining and Technology, Xu Zhou 221116 (China); Sun, Qinghe; Zhu, Wei; Yan, Wei; Qi, Jianwei [College of Materials Science and Engineering, China University of Mining and Technology, Xu Zhou 221116 (China)

    2015-11-30

    Highlights: • We fabricate a low adhesive superhydrophobic nano Cu/Al{sub 2}O{sub 3} composited Ni–Cr coating via brush plating. • We investigate the influence of process parameters on hydrophobic properties process. • We discuss the formation mechanism of structures on the surface and using water rebound height to explain the low adhesive force mechanism. - Abstract: Superhydrophobic nano Cu/Al{sub 2}O{sub 3} Ni–Cr composited coating with a low adhesive force was deposited onto the Q345 carbon steel via electro-brush plating. Surface morphologies of nano Cu/Al{sub 2}O{sub 3} Ni–Cr composited coating were investigated by scanning electron microscope (SEM). Chemical compositions were characterized by energy dispersive spectroscopy (EDS). First of all, by adjusting different process parameters such as working voltage, relative velocity, Cu particles concentration and plating time, we obtain the most optimal parameters: working voltage is 15 V, relative velocity is 4.8 m/min, Cu particles concentration is 5 g/L and plating time is 60 s. Under the best process parameters, the water contact angle reaches to 156° and a sliding angle is less than 2° on the nano Cu/Al{sub 2}O{sub 3} Ni–Cr coating. Then the mechanism of the superhydrophobic and low adhesion characteristic of this surface were explained by Cassie's model. Low adhesive force can be characterized by max rebound height of water droplet. As a result, to achieve low adhesive surface it is necessary to decrease the fraction of the solid/liquid interface under the water droplet. Finally the coating was proved to have an excellent self-cleaning performance.

  17. Cu/sub x/S-CdS thin film solar cells - aftertreatment and stability. Cu/sub x/S-CdS Duennschicht-Solarzellen - Untersuchungen ueber die Nachbehandlung und die Stabilitaet

    Energy Technology Data Exchange (ETDEWEB)

    Pfisterer, F

    1987-02-19

    The performance of Cu/sub x/S-CdS thin film solar cells can be improved significantly by a secondary treatment of the Cu layer. The physical mechanisms underlying the aftertreatment process were investigated both experimentally and theoretically. A historical review is followed by an outline of the technology and theory of these solar cells (material properties, process engineering, photovoltaic properties) and a description of Cu aftertreatment and H glowing (experimental set-up, surface potential shift, electron beam scanning). Capacity measurements in this type of thin film cell are described (space charge profile, electrolytic decomposition, copper depletion between the contact web). Aftertreatment of the copper layer enhances the solar cell efficiency, stability, and productivity, makes the immersion process less tedious, and corrects the stoichiometry. (HWJ).

  18. Dissolved trace metal (Cu, Cd, Co, Ni, and Ag) distribution and Cu speciation in the southern Yellow Sea and Bohai Sea, China

    Science.gov (United States)

    Li, Li; Xiaojing, Wang; Jihua, Liu; Xuefa, Shi

    2017-02-01

    Trace metals play an important role in biogeochemical cycling in ocean systems. However, because the use of trace metal clean sampling and analytical techniques has been limited in coastal China, there are few accurate trace metal data for that region. This work studied spatial distribution of selected dissolved trace metals (Ag, Cu, Co, Cd, and Ni) and Cu speciation in the southern Yellow Sea (SYS) and Bohai Sea (BS). In general, the average metal (Cu, Co, Cd, and Ni) concentrations found in the SYS were lower by a factor of two than those in BS, and they are comparable to dissolved trace metal concentrations in coastal seawater of the United States and Europe. Possible sources and sinks and physical and biological processes that influenced the distribution of these trace metals in the study region were further examined. Close relationships were found between the trace metal spatial distribution with local freshwater discharge and processes such as sediment resuspension and biological uptake. Ag, owing to its extremely low concentrations, exhibited a unique distribution pattern that magnified the influences from the physical and biological processes. Cu speciation in the water column showed that, in the study region, Cu was strongly complexed with organic ligands and concentrations of free cupric ion were in the range of 10-12.6-10-13.2 mol L-1. The distribution of Cu-complexing ligand, indicated by values of the side reaction coefficient α', was similar to the Chl a distribution, suggesting that in situ biota production may be one main source of Cu-complexing organic ligand.

  19. Synthesis and characterization of CdS/CuAl2O4 core-shell: application to photocatalytic eosin degradation

    Science.gov (United States)

    Bellal, B.; Trari, M.; Afalfiz, A.

    2015-08-01

    The advantages of the hetero-junction CdS/CuAl2O4 for the photocatalytic eosin degradation are reported. Composite semiconductors are elaborated by co-precipitation of CdS on the spinel CuAl2O4 giving a core-shell structure with a uniform dispersion and intimate contact of the spinel nanoparticles inside the hexagonal CdS. The Mott-Schottky plots ( C -2- V) of both materials show linear behaviors from which flat band potentials are determined. The photoactivity increases with increasing the mass of the sensitizer CdS and the best performance is achieved on CdS/CuAl2O4 (85 %/15 %). The pH has a strong influence on the degradation and the photoactivity peaks at pH 7.78. The dark adsorption eosin is weak (~4 %), hence the change in the eosin concentration is attributed to the photocatalytic process. The degradation follows a zero-order kinetic with a rate constant of 5.2 × 10-8 mol L-1 mn-1 while that of the photolysis is seven times lower (0.75 × 10-8 mol L-1 mn-1).

  20. Distribution of heavy metals (Cu, Zn and Cr in groundwater from the area of a future radioactive waste repository Saligny – Romania

    Directory of Open Access Journals (Sweden)

    Tudorache A.

    2013-04-01

    Full Text Available A study of some heavy metals (Cu, Zn and Cr concentrations in natural groundwater has been conducted, by considering samples collected from the area located in the neighbourhood of Saligny village (Cernavodă, Romania. Atomic absorption spectrometry methods with thermal and electrothermal atomization has been developed, tested and used for some heavy metals content determination. The results show various concentrations of Cu, Zn and Cr in groundwater samples.

  1. Effect of different extracting solutions on the electrodialytic remediation of CCA-treated wood waste Part I. - Behaviour of Cu and Cr

    DEFF Research Database (Denmark)

    Velizarova, E.; Ribeiro, A. B.; Mateus, E.

    2004-01-01

    Removal of Cu and Cr from chromated copper arsenate (CCA)-treated wood waste under batch electrodialytic conditions was studied. The effect of different types of extracting solutions, such as deionised water or aqueous solutions of NaCl, formic acid, oxalic acid, and EDTA, on the magnitude...... and direction of the fluxes of Cu- and Cr-containing species in the electrodialytic cell was investigated. Oxalic acid was found to have the best performance if simultaneous removal of the two elements is required (removal efficiencies of 80.5% for Cu and 87.4% for Cr, respectively). A mixture of oxalic acid...... and formic acid also led to similar removal efficiencies. In these experiments, the target elements were accumulated in both the anode and cathode compartments of the electrodialytic cell due to the formation of negatively charged complexes with the organic acids used besides the free cationic forms...

  2. Fine scale remobilisation of Fe, Mn, Co, Ni, Cu and Cd in contaminated marine sediment

    DEFF Research Database (Denmark)

    Tankere-Muller, Sophie; Zhang, Hao; Davison, William

    2007-01-01

    to less than 0.3 μM. With both DET and DGT measurements, there were sharply defined maxima of Cu and Cd within 2 mm of the sediment water interface, consistent with their release from organic material as it is oxidised. There was a Co maximum about 5–8 mm lower than the Cu and Cd maxima, apparently...... coincidental with Mn mobilisation. While there were clear Ni maxima, their location appeared to vary from being coincident with Co to a few mm above the Co maxima. The remobilisation of metals could not be explained by the pH gradients in the near-surface sediments. As sulphate reduction rates were appreciable...

  3. HEAVY METALS (Ni, Cu, Zn AND Cd CONTENT IN SERUM OF RAT FED GREEN MUSSELS

    Directory of Open Access Journals (Sweden)

    Muhammad Yudhistira Azis

    2015-11-01

    Full Text Available Green mussel (Perna viridis can playing role as bio-indicator or biomonitoring agent for heavy-metalcontaminations in the sea. In this research, the concentrations of four elements Ni, Cu, Zn and Cd in P. viridis and in the serum of rat which orally feed by P. viridis were determined by Atomic Absorption Spectrometry (AAS following dry acid digestion. Parameter analysis was evaluated by determining confidence limit for the obtained results. The result showed that there was a sequence of heavy-metal content in green mussels sample and laboratory rats serum, such as Ni < Cd < Cu < Zn. Keywords: heavy metals, green mussels, laboratory rats serum, AAS

  4. Implications of orbital hybridization on the electronic properties of doped quantum dots: the case of Cu:CdSe

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Joshua T.; Forsythe, Kyle; Hutchins, Jamie; Meulenberg, Robert W.

    2016-04-13

    This paper investigates how chemical dopants affect the electronic properties of CdSe quantum dots (QDs) and why a model that incorporates the concepts of orbital hybridization must be used to understand these properties. Extended X-ray absorption fine structure spectroscopy measurements show that copper dopants in CdSe QDs occur primarily through a statistical doping mechanism. Ultraviolet photoemission spectroscopy (UPS) experiments provide a detailed insight on the valence band (VB) structure of doped and undoped QDs. Using UPS measurements, we are able to observe photoemission from the Cu d-levels above VB maximum of the QDs which allows a complete picture of the energy band landscape of these materials. This information provides insights into many of the physical properties of doped QDs, including the highly debated near-infrared photoluminescence in Cu doped CdSe QDs. We show that all our results point to a common theme of orbital hybridization in Cu doped CdSe QDs which leads to optically and electronically active states below the conduction band minimum. Our model is supported from current–voltage measurements of doped and undoped materials, which exhibit Schottky to Ohmic behavior with Cu doping, suggestive of a tuning of the lowest energy states near the Fermi level.

  5. Role of microbial inoculation and chitosan in phytoextraction of Cu, Zn, Pb and Cd by Elsholtzia splendens - a field case

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fayuan [Agricultural College, Henan University of Science and Technology, 70 Tianjin Road, Luoyang, Henan Province 471003 (China) and Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China)]. E-mail: wfy1975@163.com; Lin Xiangui [Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China); Yin Rui [Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China)

    2007-05-15

    A field experiment was carried out to study the effect of microbial inoculation on heavy metal phytoextraction by Elsholtzia splendens and whether chitosan could have a synergistic effect with the microbial inocula. The microbial inocula consisted of a consortium of arbuscular mycorrhizal fungi and two Penicillium fungi. Three treatments were included: the control, inoculation with microbial inocula, and the inoculation combined with chitosan. Microbial inoculation increased plant biomass especially shoot dry weight, enhanced shoot Cu, Zn and Pb concentrations but did not affect Cd, leading to higher shoot Cu, Zn, Pb and Cd uptake. Compared with microbial inoculation alone, chitosan application did not affect plant growth but increased shoot Zn, Pb and Cd concentrations except Cu, which led to higher phytoextraction efficiencies and partitioning to shoots of Zn, Pb and Cd. These results indicated synergistic effects between microbial inocula and chitosan on Zn, Pb and Cd phytoextraction. - Co-application of microbial inocula and chitosan enhanced heavy metal phytoextraction by E. splendens.

  6. Role of microbial inoculation and chitosan in phytoextraction of Cu, Zn, Pb and Cd by Elsholtzia splendens - a field case

    International Nuclear Information System (INIS)

    Wang Fayuan; Lin Xiangui; Yin Rui

    2007-01-01

    A field experiment was carried out to study the effect of microbial inoculation on heavy metal phytoextraction by Elsholtzia splendens and whether chitosan could have a synergistic effect with the microbial inocula. The microbial inocula consisted of a consortium of arbuscular mycorrhizal fungi and two Penicillium fungi. Three treatments were included: the control, inoculation with microbial inocula, and the inoculation combined with chitosan. Microbial inoculation increased plant biomass especially shoot dry weight, enhanced shoot Cu, Zn and Pb concentrations but did not affect Cd, leading to higher shoot Cu, Zn, Pb and Cd uptake. Compared with microbial inoculation alone, chitosan application did not affect plant growth but increased shoot Zn, Pb and Cd concentrations except Cu, which led to higher phytoextraction efficiencies and partitioning to shoots of Zn, Pb and Cd. These results indicated synergistic effects between microbial inocula and chitosan on Zn, Pb and Cd phytoextraction. - Co-application of microbial inocula and chitosan enhanced heavy metal phytoextraction by E. splendens

  7. Chemical bath deposition of CdS thin films doped with Zn and Cu

    Indian Academy of Sciences (India)

    Abstract. Zn- and Cu-doped CdS thin films were deposited onto glass substrates by the chemical bath technique. ... Cadmium sulfide; chemical bath deposition; doping; optical window. 1. ..... at low temperature (10 K), finding similar trends than.

  8. Investigation of Cu2+, Cd2+-[Cr(SCN)6]3--DMSO systems in aqueous solution

    International Nuclear Information System (INIS)

    Cherkasova, T.G.; Tatarinova, Eh.S.; Kuznethova, O.A.; Tryasunov, B.G.

    1990-01-01

    Physicochemical methods are used to study Cd 2+ -hexarhodanochromate(3) (A) - dimethylsulfoxide (DMSO) system. Cd 3 A 2 ·4H 2 O and Cd 3 A 2 ·3DMSO composition cadmium complexes are extracted, their density is measured, magnetic properties and behaviour in different solvents are determined. Complexes individuality is proved by methods of IR spectroscopy and x-ray phase analysis. Thermal behaviour of compounds is studied under their air heating up to 1000 deg C

  9. Chemical Stability of Cd(II and Cu(II Ionic Imprinted Amino-Silica Hybrid Material in Solution Media

    Directory of Open Access Journals (Sweden)

    Buhani, Narsito, Nuryono, Eko Sri Kunarti

    2015-12-01

    Full Text Available Chemical stability of Cd(II and Cu(II ionic imprinted hybrid material of (i-Cd-HAS and i-Cu-HAS derived from silica modification with active compound (3-aminopropyl-trimethoxysilane (3-APTMS has been studied in solution media. Stability test was performed with HNO3 0.1 M (pH 1.35 to investigate material stability at low pH condition, CH3COONa 0.1 M (pH 5.22 for adsorption process optimum pH condition, and in the water (pH 9.34 for base condition. Material characteristics were carried out with infrared spectrophotometer (IR and atomic absorption spectrophotometer (AAS. At interaction time of 4 days in acid and neutral condition, i-Cd-HAS is more stable than i-Cu-HAS with % Si left in material 95.89 % (acid media, 43.82 % (close to neutral, and 9.39 % (base media.Keywords: chemical stability, amino-silica hybrid, ionic imprinting technique

  10. Chemical Stability of Cd(II and Cu(II Ionic Imprinted Amino-Silica Hybrid Material in Solution Media

    Directory of Open Access Journals (Sweden)

    Buhani Buhani

    2012-02-01

    Full Text Available Chemical stability of Cd(II and Cu(II ionic imprinted amino-silica (HAS material of (i-Cd-HAS and i-Cu-HAS derived from silica modification with active compound (3-aminopropyl-trimethoxysilane (3-APTMS has been studied in solution media.  Stability test was performed with HNO3 0.1 M (pH 1.35 to investigate material stability at low pH condition, acetat buffer at pH 5.22 for adsorption process optimum pH condition, and in the water (pH 9.34 for base condition.  Material characteristics were carried out with infrared spectrophotometer (IR and atomic absorption spectrophotometer (AAS.  At interaction time of 4 days in acid and neutral condition, i-Cd-HAS is more stable than i-Cu-HAS with % Si left in material 95.89 % (acid media, 43.82 % (close to neutral, and 9.39 % (base media.Keywords: chemical stability, amino-silica hybrid, ionic imprinting technique.

  11. Effects of Acute and Chronic Heavy Metal (Cu, Cd, and Zn Exposure on Sea Cucumbers (Apostichopus japonicus

    Directory of Open Access Journals (Sweden)

    Li Li

    2016-01-01

    Full Text Available Acute and chronic toxicity tests were conducted with sea cucumber (Apostichopus japonicus exposed to heavy metals. Acute toxicity values (96 h LC50 were 2.697, 0.133, and 1.574 mg L−1 for Zn, Cu, and Cd, respectively, and were ranked in order of toxicity: Cu > Cd > Zn. Under chronic metal exposure the specific growth rates of sea cucumbers decreased with the increase of metal concentration for all the three metals. After acute metal exposure, the oxygen consumption rate (OCR decreased. The OCRs in all groups were significantly different than control (P muscle > intestine in natural sea water. After chronic Zn, Cu, and Cd exposure, the change pattern of HK and PK in respiratory tree, muscle, and intestine varied slightly. However, the activity of the enzyme showed a general trend of increase and then decrease and the higher the exposure concentration was, the earlier the highest point of enzyme activity was obtained.

  12. Tartrazine modified activated carbon for the removal of Pb(II), Cd(II) and Cr(III).

    Science.gov (United States)

    Monser, Lotfi; Adhoum, Nafaâ

    2009-01-15

    A two in one attempt for the removal of tartrazine and metal ions on activated carbon has been developed. The method was based on the modification of activated carbon with tartrazine then its application for the removal of Pb(II), Cd(II) and Cr(III) ions at different pH values. Tartrazine adsorption data were modelled using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacities qm were 121.3, 67 and 56.7mgg(-1) at initial pH values of 1.0, 6.0 and 10, respectively. The adsorption of tartrazine onto activated carbon followed second-order kinetic model. The equilibrium time was found to be 240min at pH 1.0 and 120min at pH 10 for 500mgL(-1) tartrazine concentration. A maximum removal of 85% was obtained after 1h of contact time. The presence of tartrazine as modifier enhances attractive electrostatic interactions between metal ions and carbon surface. The adsorption capacity for Pb(II), Cd(II) and Cr(III) ions has been improved with respect to non-modified carbon reaching a maximum of 140%. The adsorption capacity was found to be a pH dependent for both modified and non-modified carbon with a greater adsorption at higher pH values except for Cr(III). The enhancement percent of Pb(II), Cd(II) and Cr(III) at different pH values was varied from 28% to 140% with respect to non-modified carbon. The amount of metal ions adsorbed using static regime was 11-40% higher than that with dynamic mode. The difference between adsorption capacities could be attributed to the applied flow rate.

  13. Size effect on the SHG properties of Cu-doped CdI2 nanocrystals

    International Nuclear Information System (INIS)

    Miah, M. Idrish

    2009-01-01

    Because the optically induced second harmonic generation (SHG) is prevented by symmetry in a centrosymmetric material, one needs to form noncentrosymmetric processes in order to observe the SHG. However, one of the efficient ways to enhance the noncentrosymmetricity of a material is to dope it with an appropriate impurity and amount. We grow Cu-doped CdI 2 layered nanocrystal structures from the mixture of CdI 2 and CuI using the standard Bridgman-Stockbarger method and investigate the nano-confined effects by studying the second-order optical effect via the measurements of SHG. The second-order susceptibility for the nanocrystals is calculated and the values at liquid helium temperature range from 0.38 to 0.83 pm V -1 for the thicknesses of 10-0.8 nm respectively. The size dependence demonstrates the nano-sized quantum-confined effect with a clear increase in the SHG with decreasing the thickness of the nanocrystal or crystal temperature. Since the local electron-phonon anharmonicity is described by third-order rank tensors in disordered systems, the SHG is very similar to that one introduced for the third-order optical susceptibility. It has been confirmed by observing the large photoluminescent yield of the pure crystals. The Raman scattering spectra taken for thin nanocrystals confirm the phonon modes originating from interlayer phonons crucially responsible for the observed effects. The obtained results show that the Cu-doped CdI 2 layered nanocrystals are promising materials for applications in optoelectronic nano-devices.

  14. Evolution with time of 12 metals (V, Cr, Mn, Co, Cu, Zn, Ag, Cd, Ba, Pb, Bi and U) and of lead isotopes in the snows of Coats Land (Antarctica) since the 1830's

    International Nuclear Information System (INIS)

    Planchon, F.

    2001-01-01

    This work shows that it is now possible to get reliable data on the occurrence of numerous heavy metals at ultra low levels in Antarctic snow, by combining ultra clean field sampling and laboratory sub-sampling procedures and the use of ultra sensitive analytical techniques such as ICP-SFMS and TIMS. It has allowed us to determine concentrations of twelve metals (V, Cr, Mn, Co, Cu, Zn, Ag, Cd, Ba, Pb, Bi et U) and lead isotopic composition in the ultra clean series of snow samples collected at Coats Land, in the Atlantic sector of Antarctica. This work presents a 150 years record of metal inputs from natural and anthropogenic sources to Antarctica from the 1830's to the early 1990's. Lead atmospheric pollution begins as early as the end of the 19. century, peaks during the 1970's-1980's and then falls sharply during recent decades. Evolution in lead isotopic abundance shows that Pb inputs to Antarctica reflect a complex blend of contributions originating from the Southern part of South America and Australia. For Cr, Cu, Zn, Ag, Bi and U, concentrations in the snow show significant increases from 1950 to 1980. These enhancements which cannot be explained by variations in natural inputs, illustrate that atmospheric pollution for heavy metals linked with anthropogenic activities in the Southern Hemisphere countries such as for example ferrous and non-ferrous metal mining and smelting is really global. Study of the time period 1920-1990, has allowed us to detail short-term (intra and inter annual) heavy metals concentration's changes. The large short-term variability, observed in Coats Land snow, shows the complex patterns of metal inputs to Antarctica, associated for instance to changes in long-range transport processes from mid-latitude to polar zone and to variability in the different natural sources, such local volcanic activity, sea-salt spray or crustal dust inputs. (author)

  15. Enriquecimiento, disponibilidad y contaminación de metales traza (Cd, Cu, Pb y Zn en sedimentos de lagunas urbanas de Concepción-Chile Enrichment, availability and contamination of trace metals (Cd, Cu, Pb and Zn in sediments of urban lagoons in Concepción, Chile

    Directory of Open Access Journals (Sweden)

    Elizabeth González Sepúlveda

    2009-01-01

    Full Text Available Trace metals (Cd, Cu, Pb and Zn enrichment, availability and contamination in superficial sediments of three interconnected urban lagoons localized in Concepción-Chile, were evaluated. According to the results of geochemical fracctionation analysis, Cu and Pb are rather associated with oxi-hydroxides, Cd is associated with exchangeable and carbonates fraction, while Zn is mainly associated with organic, oxi-hydroxides and residual fraction. The estimation of the availability percentages indicate that Cu is the most mobile metal and the less mobile is the Cd. An evaluation of the geo-accumulation index and urban industrial pollution allowed to classify the studied zone as moderately to highly contaminated.

  16. Hidden transition in multiferroic and magnetodielectric CuCrO2 evidenced by ac-susceptibility

    Science.gov (United States)

    Shukla, Kaushak K.; Pal, Arkadeb; Singh, Abhishek; Singh, Rahul; Saha, J.; Sinha, A. K.; Ghosh, A. K.; Patnaik, S.; Awasthi, A. M.; Chatterjee, Sandip

    2017-04-01

    Ferroelectric polarization, magnetic-field dependence of the dielectric constant and ac and dc magnetizations of frustrated CuCrO2 have been measured. A new spin freezing transition below 32 K is observed which is thermally driven. The nature of the spin freezing is to be a single-ion process. Dilution by the replacements of Cr ions by magnetic Mn ions showed suppression of the spin freezing transition suggesting it to be fundamentally a single-ion freezing process. The observed freezing, which is seemingly associated to geometrical spin frustration, represents a novel form of magnetic glassy behavior.

  17. Evaluation of the tolerance of three cultivars of barley to Zn, Cd or Cr in a growth chamber experiment

    Directory of Open Access Journals (Sweden)

    González A.

    2013-04-01

    Full Text Available To evaluate the tolerance of three cultivars of barley for the phytoremediation of soils contaminated by metals, a growth chamber experiment with plants exposed to increasing concentrations of Zn, Cd and Cr was conducted. Growth parameters, chlorophyll content and chlorophyll fluorescence were measured at 15 and 29 days after treatment application. Metal concentration in the plant was also measured. In all cases, the amount of metal accumulated in the plant increased by increasing the concentration of the applied metal. Chlorophyll content and chlorophyll fluorescence were higher in the first sampling indicating the negative effect on these parameters of the highest metal concentrations. Cr treatments affected significantly plant growth. Height and dry weights plants were significantly lower (p <0.05 than those treated with Zn and Cd. Physiological parameters measured and water content were also lower in plants treated with Cr. Plaisant and Pedrezuela varieties accumulated more Zn and Cd than Reinette, which accumulated greater amount of Cr than the other two cultivars. This fact shows the interest in selecting the most tolerant varieties when using a crop for phytoremediation of contaminated soils.

  18. Heavy Metals (Cu, Pb and Cd) in Water and Angel Fish (Chelmon rostractus) from Batam Coastal, Indonesia

    OpenAIRE

    Ismarti Ismarti; Ramses Ramses; Suheryanto Suheryanto; Fitrah Amelia

    2017-01-01

    Fish play an important role in human nutrition and therefore need to be carefully and routinely monitored to ensure that there are no high levels of heavy metals being transferred to human through their consumption. This study has been carried out to determine level of heavy metals (Cu, Pb, and Cd) in water and angel fish, Chelmon rostractus collected from coast of Batam. We report levels of Cu, Cd and Pb in water and angel fish from Coast Batam using Atomic Absorption Spectroscopy (AAS). Lev...

  19. Effects of Surface Charge and Functional Groups on the Adsorption and Binding Forms of Cu and Cd on Roots of indica and japonica Rice Cultivars

    Directory of Open Access Journals (Sweden)

    Zhao-Dong Liu

    2017-08-01

    Full Text Available This work was designed to understand the mechanisms of adsorption of copper (Cu and cadmium (Cd on roots of indica and japonica varieties of rice. Six varieties each of indica and japonica rice were grown in hydroponics and the chemical properties of the root surface were analyzed, including surface charges and functional groups (-COO- groups as measured by the streaming potential and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR. Binding forms of heavy metals adsorbed on rice roots were identified using sequential extraction methods. In rice roots exposed to Cu and Cd solutions, Cu existed mainly in both exchangeable and complexed forms, whereas Cd existed mainly in the exchangeable form. The amounts of exchangeable Cu and Cd and total adsorbed metal cations on the roots of indica varieties were significantly greater than those on the roots of japonica varieties, and the higher negative charges and the larger number of functional groups on the roots of indica varieties were responsible for their higher adsorption capacity and greater binding strength for Cu and Cd. Surface charge and functional groups on roots play an important role in the adsorption of Cu and Cd on the rice roots.

  20. Effects of waterborne Cu and Cd on anti-oxidative response, lipid peroxidation and heavy metals accumulation in abalone Haliotis discus hannai ino

    Science.gov (United States)

    Lei, Yanju; Zhang, Wenbing; Xu, Wei; Zhang, Yanjiao; Zhou, Huihui; Mai, Kangsen

    2015-06-01

    The aim of this study was to compare the effects of waterborne copper (Cu) and cadmium (Cd) on survival, anti-oxidative response, lipid peroxidation and metal accumulation in abalone Haliotis discus hannai. Experimental animals (initial weight: 7.49 g ± 0.01 g) were exposed to graded concentrations of waterborne Cu (0.02, 0.04, 0.06, 0.08 mg L-1) or Cd (0.025, 0.05, 0.25, 0.5 mg L-1) for 28 days, respectively. Activities of the anti-oxidative enzymes (catalase, CAT; superoxide dismutase, SOD; glutathione peroxidases, GPx; glutathione S-transferase, GST), contents of the reduced glutathione (GSH) and malondiadehyde (MDA) in the hepatopancreas, and metal accumulation in hepatopancreas and muscles were analyzed after 0, 1, 3, 6, 10, 15, 21, 28 days of metal exposure, respectively. Results showed that 0.04 mg L-1, 0.06 mg L--1 and 0.08 mg L-1 Cu caused 100% death of abalone on the 21st, 10th and 6th day, respectively. However, no dead abalone was found during the 28-day waterborne Cd exposure at all experimental concentrations. Generally, activities of SOD and GST in hepatopancreas under all Cu concentrations followed a decrease trend as the exposure time prolonged. However, these activities were firstly increased and then decreased to the control level and increased again during Cd exposure. Activities of CAT in all Cu exposure treatments were higher than those in the control. These activities were firstly increased and then decreased to the control level and increased again during Cd exposure. Contents of MDA in hepatopancreas in all Cu treatments significantly increased first and then decreased to the control level. However, the MDA contents in hepatopancreas were not significantly changed during the 28-day Cd exposure. The metals accumulation in both hepatopancreas and muscles of abalone significantly increased with the increase of waterborne metals concentration and exposure time. These results indicated that H. discus hannai has a positive anti-oxidative defense

  1. Distributions of dissolved trace metals (Cd, Cu, Mn, Pb, Ag in the southeastern Atlantic and the Southern Ocean

    Directory of Open Access Journals (Sweden)

    M. Boye

    2012-08-01

    Full Text Available Comprehensive synoptic datasets (surface water down to 4000 m of dissolved cadmium (Cd, copper (Cu, manganese (Mn, lead (Pb and silver (Ag are presented along a section between 34° S and 57° S in the southeastern Atlantic Ocean and the Southern Ocean to the south off South Africa. The vertical distributions of Cu and Ag display nutrient-like profiles similar to silicic acid, and of Cd similar to phosphate. The distribution of Mn shows a subsurface maximum in the oxygen minimum zone, whereas Pb concentrations are rather invariable with depth. Dry deposition of aerosols is thought to be an important source of Pb to surface waters close to South Africa, and dry deposition and snowfall may have been significant sources of Cu and Mn at the higher latitudes. Furthermore, the advection of water masses enriched in trace metals following contact with continental margins appeared to be an important source of trace elements to the surface, intermediate and deep waters in the southeastern Atlantic Ocean and the Antarctic Circumpolar Current. Hydrothermal inputs may have formed a source of trace metals to the deep waters over the Bouvet Triple Junction ridge crest, as suggested by relatively enhanced dissolved Mn concentrations. The biological utilization of Cu and Ag was proportional to that of silicic acid across the section, suggesting that diatoms formed an important control over the removal of Cu and Ag from surface waters. However, uptake by dino- and nano-flagellates may have influenced the distribution of Cu and Ag in the surface waters of the subtropical Atlantic domain. Cadmium correlated strongly with phosphate (P, yielding lower Cd / P ratios in the subtropical surface waters where phosphate concentrations were below 0.95 μM. The greater depletion of Cd relative to P observed in the Weddell Gyre compared to the Antarctic Circumpolar Current could be due to increase Cd uptake induced by iron-limiting conditions in these high

  2. A study on adsorption of Pb(II), Cr(Ш) and Cu(II) from aqueous ...

    African Journals Online (AJOL)

    Peanut husk has been used in this work for removing Pb(II), Cr(Ш) and Cu(II) from aqueous solution. Batch adsorption studies were carried out under different pH, initial concentration of metal ions, interfering metal ions, time and temperature. Adsorption was poor in strongly acidic solution but was improved in alkaline ...

  3. The influence of grain boundary diffusion on the electro-optical properties of CdTe/CdS solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Levi, D.H.; Albin, D.S.; Gessert, T.A.; Reedy, R.C.; Ahrenkiel, R.K. [National Renewable Energy Lab., Golden, CO (United States); Woods, L.M. [Colorado State Univ., Fort Collins, CO (United States)

    1998-09-01

    The authors report on a study of the effects of diffusion of metals through polycrystalline CdTe thin films. The metals Ni, Pd, Cu, Cr, and Te are deposited onto the back surface of 10-{micro}m thick CdTe/CdS device structures using room-temperature evaporation. The authors found that four out of the five metals produce significant changes in the photoluminescence (PL) of the near-junction CdTe material. These changes are explained in terms of spatial variations of the photoexcited carrier distribution and spatial variations in the sulfur composition of the CdTeS alloy material near the CdTeS interface. The changes in carrier distribution appear to be associated with band bending and electric fields induced by diffusion of the metals to the CdTe/CdS interface. In addition to PL measurements, the authors have also utilized a technique for detaching the CdTe film from the CdS/TCO/glass superstrate to directly access the front surface of the CdTe absorber layer. The authors have used secondary ion mass spectroscopy to measure the metal diffusion profiles from this interface.

  4. Effects of warming on uptake and translocation of cadmium (Cd) and copper (Cu) in a contaminated soil-rice system under Free Air Temperature Increase (FATI).

    Science.gov (United States)

    Ge, Li-Qiang; Cang, Long; Liu, Hui; Zhou, Dong-Mei

    2016-07-01

    Global warming has received growing attentions about its potential threats to human in recent, however little is known about its effects on transfer of heavy metals in agro-ecosystem, especially for Cd in rice. Pot experiments were conducted to evaluate Cd/Cu translocation in a contaminated soil-rice system under Free Air Temperature Increase (FATI). The results showed that warming gradually decreased soil porewater pH and increased water-soluble Cd/Cu concentration, reduced formation of iron plaque on root surface, and thus significantly increased total uptake of Cd/Cu by rice. Subsequently, warming significantly promoted Cd translocation from root to shoot, and increased Cd distribution percentage in shoot, while Cu was not significantly affected. Enhanced Cd uptake and translocation synergistically resulted in higher rice grain contamination with increasing concentration from 0.27 to 0.65 and 0.14-0.40 mg kg(-1) for Indica and Japonica rice, respectively. However increase of Cu in brown grain was only attributed to its uptake enhancement under warming. Our study provides a new understanding about the food production insecurity of heavy metal contaminated soil under the future global warming. Copyright © 2016. Published by Elsevier Ltd.

  5. Enhanced photovoltaic performance of quantum dot-sensitized solar cells with a progressive reduction of recombination using Cu-doped CdS quantum dots

    Science.gov (United States)

    Muthalif, Mohammed Panthakkal Abdul; Lee, Young-Seok; Sunesh, Chozhidakath Damodharan; Kim, Hee-Je; Choe, Youngson

    2017-02-01

    In this article, we have systematically probed the effect of Cu-doping in CdS quantum dots (QDs) to enhance the photovoltaic performance of the quantum dot-sensitized solar cells (QDSSCs). The Cu-doped CdS photoanodes were prepared by successive ionic layer adsorption and reaction (SILAR) method and the corresponding cell devices were fabricated using CuS counter electrodes with a polysulfide electrolyte. The photovoltaic performance results demonstrate that 3 mM Cu-doped CdS QDs based QDSSCs exhibit the efficiency (η) of 3% including JSC = 9.40 mA cm-2, VOC = 0.637 V, FF = 0.501, which are higher than those with bare CdS (η = 2.05%, JSC = 7.12 mA cm-2, VOC = 0.588 V, FF = 0.489). The structural, topographical and optical properties of the thin films have been studied with the help of X-ray diffraction pattern (XRD), atomic force microscopy (AFM) and UV-vis spectrophotometer. Electrochemical impedance spectroscopy (EIS) and open circuit voltage decay (OCVD) measurements indicate that Cu-dopant can inhibit the charge recombination at the photoanode/electrolyte interface and extend the lifetime of electrons. These results reveal that incorporation of copper metal in CdS QDs is a simple and effective method to improve the photovoltaic properties of QDSSCs.

  6. Optical analysis of lens-like Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Odeh, Ali Abu; Ayub, R.M. [University Malaysia Perlis, Institute of Nano Electronic Engineering, Kangar, Perlis (Malaysia); Al-Douri, Y. [University Malaysia Perlis, Institute of Nano Electronic Engineering, Kangar, Perlis (Malaysia); University of Sidi-Bel-Abbes, Physics Department, Faculty of Science, Sidi-Bel-Abbes (Algeria); Ameri, M. [Universite Djilali Liabes de Sidi Bel- Abbes, Laboratoire Physico-Chimie des Materiaux Avances (LPCMA), Sidi-Bel-Abbes (Algeria); Bouhemadou, A. [University of Setif 1, Laboratory for Developing New Materials and Their Characterization, Setif (Algeria); Prakash, Deo [SMVD University, Faculty of Engineering, School of Computer Science and Engineering, Kakryal, Katra, J and K (India); Verma, K.D. [S.V. College, Material Science Research Laboratory, Department of Physics, Aligarh, U.P. (India)

    2016-10-15

    Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures with different copper concentrations (0.2, 0.4, 0.6, 0.8 and 1.0 M) were successfully synthesized on n-type silicon substrates using spin coating technique with annealing temperature at 300 C. Optical properties were analyzed through UV-Vis and Photoluminescence spectroscopies, and thus, there is a change in energy band gap with increasing Cu concentration from 0.2 to 1.0 M. The structural properties of Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures were investigated by X-ray diffraction. The particles size and shape have a direct relationship with copper concentration. Morphological and topographical studies were carried out by using scanning electron microscopy and atomic force microscopy. The obtained results are investigated to be available in the literature for future studies. (orig.)

  7. The effects of microalloying with Cd on precipitation processes in Al-1.7 Cu-0.3 mg (At. %) alloys

    International Nuclear Information System (INIS)

    Sofyan, Bondan T.

    2002-01-01

    The present work investigates the effects of microalloying with Cd on precipitation processes in Al-1.7 Cu-0.3 mg (At. %) alloys. Analytical STEM (Scanning Transmission Electron Microscope) revealed the presence of clusters rich in Cd and Mg at early stages of ageing, which is believed to be responsible in promoting the nucleation of θ (Al,Cu) in the alloy on its (001) planes. The Cd-Mg clusters then grow as Cd-Mg-rich particles when ageing is continued beyond the peak hardness. The presence of Cd-Mg-rich clusters is thought to play an important role on the nucleation of θ phase by accommodating the misfit strain on the non-coherent rim of the phase. The accommodation of misfit strain is made available by the presence of large amount of vacancies, which is trapped by Cd and Mg atoms during quenching, around θ platelet nuclei

  8. The Investigation of Heavy Metal Content (Cu, Cd, Pb in Sapu-Sapu Fish (Hypostomus plecostomus in Bengawan Solo River

    Directory of Open Access Journals (Sweden)

    Ristiyana Eko Setyarini

    2016-12-01

    Full Text Available A study had been carried out to investigate heavy metal (Cu, Cd, Pb content in sapu-sapu fish (hypostomus plecostomus in Bengawan Solo river. The type of this research was observational research, with sapu-sapu fish inhabit Bengawan Solo River as the population. The samples were taken with purposive random sampling. Nine sapu-sapu fishes taken from 3 places, i.e.: Nguter Sukoharjo area, Premulung river outlet and Anyar river, 3 fishes from each palce, and then take examined the content of heavy metal. The result of study showed that the average content of Cu: 0.027 mg/100gr, Cd: 0.005 mg/100gr and Pb: 0.042 mg/100gr. Hence, sapu-sapu fish in Be3ngawan Solo had been contaminated with heavy metal (Cu, Cd, and Pb and should not be consumed.

  9. Decorated Shastry-Sutherland lattice in the spin-(1)/(2) magnet CdCu2(BO3)2

    Science.gov (United States)

    Janson, O.; Rousochatzakis, I.; Tsirlin, A. A.; Richter, J.; Skourski, Yu.; Rosner, H.

    2012-02-01

    We report the microscopic magnetic model for the spin-1/2 Heisenberg system CdCu2(BO3)2, one of the few quantum magnets showing the 1/2-magnetization plateau. Recent neutron diffraction experiments on this compound [M. Hase , Phys. Rev. BPLRBAQ0556-280510.1103/PhysRevB.80.104405 80, 104405 (2009)] evidenced long-range magnetic order, inconsistent with the previously suggested phenomenological magnetic model of isolated dimers and spin chains. Based on extensive density functional theory band structure calculations, exact diagonalizations, quantum Monte Carlo simulations, third-order perturbation theory as well as high-field magnetization measurements, we find that the magnetic properties of CdCu2(BO3)2 are accounted for by a frustrated quasi-2D magnetic model featuring four inequivalent exchange couplings: the leading antiferromagnetic coupling Jd within the structural Cu2O6 dimers, two interdimer couplings Jt1 and Jt2, forming magnetic tetramers, and a ferromagnetic coupling Jit between the tetramers. Based on comparison to the experimental data, we evaluate the ratios of the leading couplings Jd : Jt1 : Jt2 : Jit = 1 : 0.20 : 0.45 : -0.30, with Jd of about 178 K. The inequivalence of Jt1 and Jt2 largely lifts the frustration and triggers long-range antiferromagnetic ordering. The proposed model accounts correctly for the different magnetic moments localized on structurally inequivalent Cu atoms in the ground-state magnetic configuration. We extensively analyze the magnetic properties of this model, including a detailed description of the magnetically ordered ground state and its evolution in magnetic field with particular emphasis on the 1/2-magnetization plateau. Our results establish remarkable analogies to the Shastry-Sutherland model of SrCu2(BO3)2, and characterize the closely related CdCu2(BO3)2 as a material realization for the spin-1/2 decorated anisotropic Shastry-Sutherland lattice.

  10. X-ray attenuation coefficient measurements for photon energies 4.508-13.375 keV in Cu, Cr and their compounds and the validity of the mixture rule

    International Nuclear Information System (INIS)

    Turgut, Ue.; Simsek, Oe.; Bueyuekkasap, E.; Ertugrul, M.

    2004-01-01

    To investigate the validity of the mixture rule which is used to compute the mass attenuation coefficients in compounds, the total mass attenuation coefficients for Cu, Cr elements and Cu 2 O, CuC 2 O 4 , CuCl 2 ·2H 2 O, Cu(C 2 H 3 O 2 ) 2 ·H 2 O, Cr 2 O 3 , Cr(NO 3 ) 3 , Cr 2 (SO 4 ) 3 ·H 2 O, Cr 3 (CH 3 CO 7 )(OH) 2 compounds were measured at photon energies between 4.508 and 13.375 keV by using the secondary excitation method. Ti, Mn, Fe, Ni, Zn, Ge, As, Rb elements were used as secondary exciters. 59.5 keV gamma rays emitted from an 241 Am annular source were used to excite the secondary exciters and Kα (K-L 3 , L 2 ) rays emitted from the secondary exciter were counted by a Si(Li) detector with a resolution of 160 eV at 5.9 keV. Our measurements indicate that the mixture rule is not a suitable method for the computation of mass attenuation coefficients of compounds especially at an energy that is near the absorption edge. Obtained values were compared with theoretical values

  11. Production of Renewable Hydrogen from Glycerol Steam Reforming over Bimetallic Ni-(Cu,Co,Cr Catalysts Supported on SBA-15 Silica

    Directory of Open Access Journals (Sweden)

    Alicia Carrero

    2017-02-01

    Full Text Available Glycerol steam reforming (GSR is a promising alternative to obtain renewable hydrogen and help the economics of the biodiesel industry. Nickel-based catalysts are typically used in reforming reactions. However, the choice of the catalyst greatly influences the process, so the development of bimetallic catalysts is a research topic of relevant interest. In this work, the effect of adding Cu, Co, and Cr to the formulation of Ni/SBA-15 catalysts for hydrogen production by GSR has been studied, looking for an enhancement of its catalytic performance. Bimetallic Ni-M/SBA-15 (M: Co, Cu, Cr samples were prepared by incipient wetness co-impregnation to reach 15 wt % of Ni and 4 wt % of the second metal. Catalysts were characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES, N2-physisorption, X-ray powder diffraction (XRD, hydrogen temperature programmed reduction (H2-TPR, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and thermogravimetric analyses (TGA, and tested in GSR at 600 °C and atmospheric pressure. The addition of Cu, Co, and Cr to the Ni/SBA-15 catalyst helped to form smaller crystallites of the Ni phase, this effect being more pronounced in the case of the Ni-Cr/SBA-15 sample. This catalyst also showed a reduction profile shifted towards higher temperatures, indicating stronger metal-support interaction. As a consequence, the Ni-Cr/SBA-15 catalyst exhibited the best performance in GSR in terms of glycerol conversion and hydrogen production. Additionally, Ni-Cr/SBA-15 achieved a drastic reduction in coke formation compared to the Ni/SBA-15 material.

  12. CELULE FOTOVOLTAICE CU HETEROJONCŢIUNEA nCdS-pInP

    Directory of Open Access Journals (Sweden)

    Vasile BOTNARIUC

    2015-12-01

    Full Text Available Au fost studiate proprietăţile electrice şi fotoelectrice ale heterojoncţiunilor nCdS-pInP cu şi fără strat epitaxial inter-mediar poInP. S-a stabilit că la polarizări directe în mecanismul de transport al curentului predomină procesele de recom-binare în regiunea de sarcină spaţială. La polarizări inverse predomină procesele de tunelare. Prezenţa stratului epitaxial poInP depus repetat măreşte ISC până la 28,2 mA·cm-2, UCD până la 0,780 V, iar eficienţa conversiei energiei până la 15% la 300 K şi iluminare 100 mW/cm2. Fotosensibilitatea CF nCdS-poInP-pInP corespunde intervalului λ=550...950 nm cu un maximum plat localizat în intervalul λ=700...850 nm.HETEROJONCTION nCdS–pInP FOTOVOLTAIC CELLSElectrical and photoelectrical properties of nCdS-pInP hetero-junctions with and without intermediate poInP epitaxial layer were studied. It was established that the current flow mechanism at direct biases is determined mainly by the recombi-nation processes in the space charge region of the junction. At the reverse biases the tunneling processes are predominant. The presence of poInP layer leads to the photo-electrical parameters enhancing of hetero-junction: short circuit current increases up to 28,2 mA·cm -2, open circuit voltage up to 0,780V and the efficiency of solar energy conversion up to 15 % (at 300 K and illumination of 100mw/cm2. The photo-sensitivity of nCdS- poInP -pInP is in the wavelength region of λ= 550-950nm with a maximum localized to λ=700-850nm.

  13. Investigation of Au9+ swift heavy ion irradiation on CdS/CuInSe2 thin films

    International Nuclear Information System (INIS)

    Joshi, Rajesh A.; Taur, Vidya S.; Singh, Fouran; Sharma, Ramphal

    2013-01-01

    In the present manuscript we report about the preparation of CdS/CuInSe 2 heterojunction thin films by chemical ion exchange method and investigation of 120 MeV Au 9+ swift heavy ions (SHI) irradiation effect on its physicochemical as well as optoelectronic properties. These pristine (as grown) samples are irradiated with 120 MeV Au 9+ SHI of 5×10 11 and 5×10 12 ions/cm 2 fluencies and later on characterized for structural, compositional, morphological, optical and I–V characteristics. X-ray diffraction (XRD) pattern obtained from pristine and irradiated films shows considerable modifications in peak intensity as well as rising of some new peaks, corresponding to In 2 Se 3 , Cu 3 Se 2 and CuIn 2 Se 3 materials. Transmission electron microscope (TEM) images show decrease in grain size upon increase in irradiation ion fluencies, which is also supported from the observation of random and uneven distribution of nano-grains as confirmed through scanning electron microscope (SEM) images. Presence of Cd, Cu, In, S and Se in energy dispersive X-ray spectrum analysis (EDAX) confirms the expected and observed elemental composition in thin films, the absorbance peaks are related to band to band transitions and spin orbit splitting while energy band gap is observed to increase from 1.36 for pristine to 1.53 eV for SHI irradiated thin films and I–V characteristics under illumination to 100 mW/cm 2 light source shows enhancement in conversion efficiency from 0.26 to 1.59% upon irradiation. - Highlights: • Nanostructured CdS/CuInSe 2 can be grown by chemical ion exchange method. • Physicochemical and optoelectronic properties can be modified by 120 MeV Au 9+ SHI Irradiation. • Solar energy conversion efficiency improved from 0.26 to 1.59% in CdS/CuInSe 2 upon irradiation

  14. Thermophysical Properties of Cold and Vacuum Plasma Sprayed Cu-Cr-X Alloys, NiAl and NiCrAlY Coatings. Part 1; Electrical and Thermal Conductivity, Thermal Diffusivity, and Total Hemispherical Emissivity

    Science.gov (United States)

    Raj, S. V.

    2017-01-01

    This two-part paper reports the thermophysical properties of several cold and vacuum plasma sprayed monolithic Cu and Ni-based alloy coatings. Part I presents the electrical and thermal conductivity, thermal diffusivity, and total hemispherical emissivity data while Part II reports the specific heat capacity data for these coatings. Metallic copper alloys, stoichiometric NiAl and NiCrAlY coatings were fabricated by either the cold sprayed or the vacuum plasma spray deposition processes for thermal property measurements between 77 and 1223 K. The temperature dependencies of the thermal conductivities, thermal diffusivities, electrical conductivities and total hemispherical emissivities of these cold and vacuum sprayed monolithic coatings are reported in this paper. The electrical and thermal conductivity data correlate reasonably well for Cu-8%Cr-1%Al, Cu-23%Cr-5%Al and NiAl in accordance with the Wiedemann-Franz (WF) law although a better fit is obtained using the Smith-Palmer relationship. The Lorentz numbers determined from the WF law are close to the theoretical value.

  15. Abnormalities in soluble CD147 / MMPs / TIMPs axis in Ankylosing Spondylitis patients with and without a history of Acute Anterior Uveitis / Anomalii ale axei CD147 solubil / MMPs / TIMPs la pacienții cu spondilită anchilozantă cu sau fără uveită acută anterioară

    Directory of Open Access Journals (Sweden)

    Mitulescu Traian Costin

    2014-12-01

    Full Text Available Spondilita Anchilozantă (SA este prototipul formei axiale a spondiloartritelor. În pofida studiilor extinse, sunt încă incomplet înțelese mecansimele complexe legate de procesele celulare și moleculare anormale din SA. Printre mediatorii inflamației, cum ar fi citokinele proinflamatoare, NOS-2, chemokinele, care conduc la inflamație, metaloproteinazele de matrice (MMPs joacă un rol important în procesele inflamatoare care caracterizează SA. De aceea, ne-am propus să evaluăm dacă perturbări ale homeostaziei inductorului extracelular de MMPs (EMMPRIN/CD147, MMPs și inhibitorilor tisulari ai MMPs (TIMPs joacă un rol în evoluția SA în special la pacienții care au în istoricul lor Uveită Acută Anterioară (UAA. În acest scop seruri de la pacienți cu SA și de la donatori sănătoși (DS au fost analizate pentru nivelurile de CD147 solubil (sCD147, MMP-3 și TIMP-1 prin tehnica imunoenzimatica ELISA și pentru activitatea gelatinazelor MMP-2 si MMP-9 folosind gelatin zimografia. Rezultatele experimentale au arătat că nivelurile de sCD147, MMP-3 si TIMP-1 sunt semnificativ crescute la pacienții cu SA comparativ cu DS. sCD147 ca și raportul MMP-2/sCD147 a diferențiat pacienții cu UAA de cei fără UAA în istoricul lor. La pacienții cu SA rapoartele MMP-2/sCD147, MMP-3/sCD147 și MMP-3/TIMP-1 au sugerat dezechilibrul dintre MMPs și reglatorii lor. Aceste rezultate sugerează că rapoartele MMPs/sCD147 pot deveni biomarkeri potențiali pentru întărirea caracterizării pacienților cu SA și pentru a prognoza evoluția bolii. Corelațiile pozitive și negative dintre anumite caracteristici experimentale și/sau clinice ale pacienților cu SA și terapie subliniază de asemenea utilitatea evaluării acestor biomarkeri pentru a identifica o terapie individualizată și eficientă.

  16. Regressional modeling of electrodialytic removal of Cu, Cr and As from CCA treated timber waste

    DEFF Research Database (Denmark)

    Moreira, E.E.; Ribeiro, Alexandra B.; Mateus, Eduardo

    2005-01-01

    ) removal of Cu, Cr and As from CCA treated timber waste. The method uses a low-level direct current as the cleaning agent, combining the electrokinetic movement of ions in the matrix with the principle of electrodialysis. The technique was tested in eight experiments using a laboratory cell on sawdust...

  17. Occurrences of dissolved trace metals (Cu, Cd, and Mn) in the Pearl River Estuary (China), a large river-groundwater-estuary system

    Science.gov (United States)

    Wang, Deli; Lin, Wenfang; Yang, Xiqian; Zhai, Weidong; Dai, Minhan; Arthur Chen, Chen-Tung

    2012-12-01

    This study for the first time examined dissolved metals (Cu, Cd, and Mn) together with dissolved oxygen and carbonate system in the whole Pearl River Estuary system, from the upper rivers to the groundwater discharges until the estuarine zone, and explored their potential impacts in the adjacent northern South China Sea (SCS) during May-August 2009. This river-groundwater-estuary system was generally characterized by low dissolved metal levels as a whole, whilst subject to severe perturbations locally. In particular, higher dissolved Cu and Cd occurred in the North River (as high as 60 nmol/L of Cu and 0.99 nmol/L of Cd), as a result of an anthropogenic source from mining activities there. Dissolved Cu levels were elevated in the upper estuary near the city of Guangzhou (Cu: ˜40 nmol/L), which could be attributable to sewage and industrial effluent discharges there. Elevated dissolved metal levels (Cu: ˜20-40 nmol/L; Cd: ˜0.2-0.8 nmol/L) also occurred in the groundwaters and parts of the middle and lower estuaries, which could be attributable to a series of geochemical reactions, e.g., chloride-induced desorption from the suspended sediments, oxidation of metal sulfides, and the partial dissolution of minerals. The high river discharge during our sampling period (May-August 2009) significantly diluted anthropogenic signals in the estuarine mixing zone. Of particular note was the high river discharge (which may reach 18.5 times as high as in the dry season) that transported anthropogenic signals (as indicated by dissolved Cu and Cd) into the adjacent shelf waters of the northern SCS, and might have led to the usually high phytoplankton productivity there (chlorophyll-a value >10 μg/L).

  18. Radiotracer study of the adsorption of Fe(III), Cr(III) and Cd(II) on natural and chemically modified Slovak zeolite

    International Nuclear Information System (INIS)

    Foeldesova, M.; Dillinger, P.; Lukac, P.

    1998-01-01

    In order to minimize the contamination of environment with metals in ionic form the more types of natural and chemically modified zeolites were examined to their uptake of Fe(III), Cr(III) and Cd(II) from water solutions by batch radio-exchange equilibration method. In this study was used zeolitic tuff from deposit Nizny Hrabovec (content of clinoptilolite 50-70%) with the grain size from 1.2 to 2.2 mm. The granules of zeolite were modified with the following NaOH solutions: ).5, 1, 2 and 4 mol.l -1 at 80 grad C for 4 hours. The sorption of Fe, Cr and Cd ions on all types of zeolites was studied by radio-exchange method and the sorption of Fe and Cr also flame atomic absorption method. From sorption curves the sorption coefficients were calculated. The results obtained in this work show that zeolites modified with NaOH solution are suitable for adsorption of Fe(III), Cr(III) and Cd(II) from underwater, waste water, feed water and coolant water from nuclear plants. The adsorbed zeolites can be solidified by conventional way

  19. The leaching kinetics of cadmium from hazardous Cu-Cd zinc plant residues.

    Science.gov (United States)

    Li, Meng; Zheng, Shili; Liu, Biao; Du, Hao; Dreisinger, David Bruce; Tafaghodi, Leili; Zhang, Yi

    2017-07-01

    A large amount of Cu-Cd zinc plant residues (CZPR) are produced from the hydrometallurgical zinc plant operations. Since these residues contain substantial amount of heavy metals including Cd, Zn and Cu, therefore, they are considered as hazardous wastes. In order to realize decontamination treatment and efficient extraction of the valuable metals from the CZPR, a comprehensive recovery process using sulfuric acid as the leaching reagent and air as the oxidizing reagent has been proposed. The effect of temperature, sulfuric acid concentration, particle size, solid/liquid ratio and stirring speed on the cadmium extraction efficiency was investigated. The leaching kinetics of cadmium was also studied. It was concluded that the cadmium leaching process was controlled by the solid film diffusion process. Moreover, the order of the reaction rate constant versus H 2 SO 4 concentration, particle size, solid/liquid ratio and stirring speed was calculated. The XRD and SEM-EDS analysis results showed that the main phases of the secondary sulfuric acid leaching residues were lead sulfate and calcium sulfate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Distribution of various forms of Cd, Pb and Cu in the Wadge Bank region (Arabian Sea)

    Digital Repository Service at National Institute of Oceanography (India)

    George, M.D.

    Labile, nonlabile and particulate forms of Cd,Pb and Cu were determined in 29 water samples collected from a depth of 5 m, from the Wadge Bank area. Labile Cd varied from 0.1 to 0.2 mu g.l-1 while nonlabile fraction was in the range 0.1 to 0.3 mu gl...

  1. Determination of the impurity content of B, Cd, Cu, W in uranium-gadolinium pellets

    International Nuclear Information System (INIS)

    Chen Lan; Zhang Jiansheng; Zhang Bo; Shao Yan

    2010-01-01

    This paper deals with determining the impurity content of B, Cd, Cu and W in Uranium-gadolinium Pellets. Set up the method: dissolve the sample in nitric acid and mannitol; use the 3 mol/L HNO 3 solution for mobile phase, CL-TBP resin for stationary phase to separate the Uranium from its nitric acid solution, collect the leaching solution , analysed by the Multi-component spectra fitting ICP-AES. The studies also includes the setting up and validity testing of the MSF model. The studies conducted suggests that:the sampling mass 0.2000 g, prepared sample volume is 6 mL; range of the determination concentration Cu, W(3-300) μg/g; B, Cd (0.3-30) μg/g .The recovery of the impurities is (89-120)%, relative standard deviation is better than 8%. (authors)

  2. Optically induced second-harmonic generation in CdI sub 2 -Cu layered nanocrystals

    CERN Document Server

    Voolless, F; Hydaradjan, W

    2003-01-01

    A large enhancement (up to 0.40 pm V sup - sup 1) of the second-order optical susceptibility was observed in CdI sub 2 -Cu single-layered nanocrystals for the Nd:YAG fundamental laser beam lambda = 1.06 mu m. The Cu impurity content and nanolayer thickness of the cleaved layers (about several nanometres) play a crucial role in the observed effect. The temperature dependence of the optical second-harmonic generation (SHG) together with its correlation with Raman spectra of low-frequency modes indicate a key role for the UV-induced anharmonic electron-phonon interactions in the observed effect. The maximal output UV-induced SHG was achieved for a Cu content of about 0.5% and at liquid helium temperatures.

  3. Electrodialytic removal of Cu, Cr, and As from chromated copper arsenate-treated timber waste

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, A.B.; Mateus, E.P.; Ottosen, L.M.; Bech-Nielsen, G.

    2000-03-01

    Waste of wood treated with chromated copper arsenate (CCA) is expected to increase in volume over the next decades. Alternative disposal options to landfilling are becoming more attractive to study, especially those that promote reuse. The authors have studied the electrodialytic removal of Cu, Cr, and As from CCA-treated timber wastes. The method uses a low-level direct current as the cleaning agent, combining the electrokinetic movement of ions in the matrix with the principle of electrodialysis. The technique was tested in four experiments using a laboratory cell on sawdust of an out-of-service CCA-treated Pinus pinaster Ait. pole. The duration of all the experiments was 30 days, and the current density was kept constant at 0.2 mA/cm{sup 2}. The experiments differ because in one the sawdust was saturated with water (experiment 1) and in the rest it was saturated with oxalic acid, 2.5, 5, and 7.5% (w/w), respectively, in experiments 2--4. The highest removal rates obtained were 93% of Cu, 95% of Cr, and 99% of As in experiment 2. Other experimental conditions might possibly optimize the removal rates.

  4. [Response of Nostoc flageliforme cell to Cu2+, Cr2+ and Pb2+ stress].

    Science.gov (United States)

    Guo, Jinying; Shi, Mingke; Zhao, Yanli; Ren, Guoyan; Yi, Junpeng; Niu, Leilei; Li, Juan

    2013-06-04

    This study aimed to investigate the effects of Cu2+, Cr2+ and Pb2+ stress on Nostoc flagelliforme cell. The response of Nostoc flagelliforme cell was analyzed under the stress. The modified BG11 culture medium containing different heavy metal ions of 0, 0.1, 1.0, 10, 100 mg/L was used to cultivate Nostoc flagelliforme cell at 25 degrees C and light intensity of 80 micromol/(m x s). Electrolyte leakage, the activities of superoxide dismutase, the content of malondialdehyde, proline, soluble protein and trehalose were analyzed. Under 1 - 100 mg/L Cu2+, Cr2+ and Pb2+ stress, electrolyte leakage and malondialdehyde contents in Nostoc flagelliforme cell were higher than those in the control group during heavy metal ions stress. Meanwhile, superoxide dismutase activity increased slightly under 10 mg/L, but was lower afterwards. The contents of proline, soluble protein and trehalose increased under 10 mg/L heavy metal ions stress, while declined under extreme heavy metal ions stress (100 mg/L). Nostoc flagelliforme cell has resistance to low heavy metal ions stress, but is damaged badly under extreme heavy metal ions stress.

  5. Continuous biosorption of Pb/Cu and Pb/Cd in fixed-bed column using algae Gelidium and granulated agar extraction algal waste.

    Science.gov (United States)

    Vilar, Vítor J P; Loureiro, José M; Botelho, Cidália M S; Boaventura, Rui A R

    2008-06-15

    Continuous metal ions biosorption from Pb/Cu and Pb/Cd solutions onto seaweed Gelidium sesquipedale and a composite material prepared from an industrial algal waste was performed in a packed bed column. A binary Langmuir equation describes well the equilibrium data and indicates a good adsorption capacity. In the sorption process, Cd and Cu break through the column faster than Pb due to its lower affinity for the biosorbent. An overshoot in the outlet Cd concentration was observed and explained by competitive adsorption between Pb and Cd, whereby the higher Pb affinity for the biosorbent displaces bound Cd ions. A small overshoot happens for Cu adsorption in the presence of Pb ions. Desorption using 0.1 M HNO3 as eluant, was 100% effective. A mass transfer model for the adsorption and desorption processes, considering an external and intraparticle film resistance, adequately simulates the column performance. A binary Langmuir equation was used to describe equilibrium for the saturation process and a mass action law for the desorption process. Elution process is defined as an ion exchange mechanism, between protons and metal ions.

  6. Continuous biosorption of Pb/Cu and Pb/Cd in fixed-bed column using algae Gelidium and granulated agar extraction algal waste

    Energy Technology Data Exchange (ETDEWEB)

    Vilar, Vitor J.P. [LSRE-Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)], E-mail: vilar@fe.up.pt; Loureiro, Jose M. [LSRE-Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)], E-mail: loureiro@fe.up.pt; Botelho, Cidalia M.S. [LSRE-Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)], E-mail: cbotelho@fe.up.pt; Boaventura, Rui A.R. [LSRE-Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)], E-mail: bventura@fe.up.pt

    2008-06-15

    Continuous metal ions biosorption from Pb/Cu and Pb/Cd solutions onto seaweed Gelidium sesquipedale and a composite material prepared from an industrial algal waste was performed in a packed bed column. A binary Langmuir equation describes well the equilibrium data and indicates a good adsorption capacity. In the sorption process, Cd and Cu break through the column faster than Pb due to its lower affinity for the biosorbent. An overshoot in the outlet Cd concentration was observed and explained by competitive adsorption between Pb and Cd, whereby the higher Pb affinity for the biosorbent displaces bound Cd ions. A small overshoot happens for Cu adsorption in the presence of Pb ions. Desorption using 0.1 M HNO{sub 3} as eluant, was 100% effective. A mass transfer model for the adsorption and desorption processes, considering an external and intraparticle film resistance, adequately simulates the column performance. A binary Langmuir equation was used to describe equilibrium for the saturation process and a mass action law for the desorption process. Elution process is defined as an ion exchange mechanism, between protons and metal ions.

  7. Continuous biosorption of Pb/Cu and Pb/Cd in fixed-bed column using algae Gelidium and granulated agar extraction algal waste

    International Nuclear Information System (INIS)

    Vilar, Vitor J.P.; Loureiro, Jose M.; Botelho, Cidalia M.S.; Boaventura, Rui A.R.

    2008-01-01

    Continuous metal ions biosorption from Pb/Cu and Pb/Cd solutions onto seaweed Gelidium sesquipedale and a composite material prepared from an industrial algal waste was performed in a packed bed column. A binary Langmuir equation describes well the equilibrium data and indicates a good adsorption capacity. In the sorption process, Cd and Cu break through the column faster than Pb due to its lower affinity for the biosorbent. An overshoot in the outlet Cd concentration was observed and explained by competitive adsorption between Pb and Cd, whereby the higher Pb affinity for the biosorbent displaces bound Cd ions. A small overshoot happens for Cu adsorption in the presence of Pb ions. Desorption using 0.1 M HNO 3 as eluant, was 100% effective. A mass transfer model for the adsorption and desorption processes, considering an external and intraparticle film resistance, adequately simulates the column performance. A binary Langmuir equation was used to describe equilibrium for the saturation process and a mass action law for the desorption process. Elution process is defined as an ion exchange mechanism, between protons and metal ions

  8. SEPARATION OF Fe (III, Cr(III, Cu(II, Ni(II, Co(II, AND Pb(II METAL IONS USING POLY(EUGENYL OXYACETIC ACID AS AN ION CARRIER BY A LIQUID MEMBRANE TRANSPORT METHOD

    Directory of Open Access Journals (Sweden)

    La Harimu

    2010-06-01

    Full Text Available Fe (III, Cr(III, Cu(II, Ni(II, Co(II, and Pb(II  metal ions had been separated using poly(eugenyl oxyacetic acid as an ion carrier by bulk liquid membrane transport method. The effect of pH, polyeugenyl oxyacetic acid ion carrier concentration, nitric acid concentration in the stripping solution, transport time, and metal concentration were optimized. The result showed that the optimum condition for transport of metal ions was at pH 4 for ion Fe(III and at pH 5 for Cr(III, Cu(II, Ni(II, Co(II, and Pb(II ions. The carrier volumes were optimum with concentration of 1 x 10-3 M at 7.5 mL for Cr(III, Cu (II,  Ni(II, Co(II ions and at 8.5 mL for Fe(III and Pb(II ions. The concentration of HNO3 in stripping phase was optimum at 2 M for Fe(III and Cu(II ions, 1 M for Cr(III, Ni(II and Co(II ions, and 0.5 M for Pb(II ion. The optimum transport times were 36 h for Fe(III and Co(II ions, and 48 h for Cr(III, Cu (II, Ni(II, and Pb(II ions. The concentration of metal ions accurately transported were 2.5 x 10-4 M for Fe(III and Cr(III ions, and 1 M for Cu (II, Ni(II, Co(II, and Pb(II ions. Compared to other metal ions the transport of Fe(III was the highest with selectivity order of Fe(III > Cr(III > Pb(II > Cu(II > Ni(II > Co(II. At optimum condition, Fe(III ion was transported through the membrane at 46.46%.   Keywords: poly(eugenyl oxyacetic acid, transport, liquid membrane, Fe (III, Cr(III, Cu(II, Ni(II, Co(II, and Pb(II ions

  9. Thermal cycling tests of 1st wall mock-ups with beryllium/CuCrZr bonding

    International Nuclear Information System (INIS)

    Uda, M.; Iwadachi, T.; Uchida, M.; Yamada, H.; Nakamichi, M.; Kawamura, H.

    2004-01-01

    The innovative bonding technology between beryllium and CuCrZr with Hot Isostatic Pressing (HIP) has been proposed for the manufacturing of the ITER first wall. In the next step, thermal cycling test of first wall mock-ups manufactured with the bonding technology, were carried out under the ITER heat load condition. The test condition is 1000 cycles of On and Off under 5 MW/m 2 , and two types of the mock-up were manufactured for evaluation of the effects on HIP temperature (520 degree C and 610 degree C). The tensile properties of the bonding were also evaluated in room temperature and 200 degree C. As for the results of the thermal cycling tests, the temperature near the bonding interface were scarcely any change up to 1000 cycles, and obvious damage of the mock-up was not detected under the tests. As for the results of the tensile tests in 200 degree C, the test pieces of the HIP bonding at 610 degree C were broken in parent CuCrZr material, not broken in the bonding interface. (author)

  10. Kinetics of Cd2+ and Cr3+ Sorption from Aqueous Solutions Using Mercaptoacetic Acid Modified and Unmodified Oil Palm Fruit Fibre(Elaeis guineensis) Adsorbents

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The kinetics of the sorption of Cd2+ and Cr3+ from aqueous solutions by mercaptoacetic acid modified and unmodified oil palm fruit fibre adsorbents were investigated. The results indicate that sorption equilibrium was reached within 60 min for both metals. Also, the removal efficiency of the three adsorbents was observed to increase for both metals with stronger treatments with mercaptoacetic acid. This may be attributed to the influence of the thiolation of the adsorbents. Furthermore, Cr3+ had higher removal percentages than Cd2+ for all the adsorbents. The sorption mechanism based on the intraparticle diffusion model shows that Cd2+ sorption is better described than Cr3+. The intraparticle diffusion rate constants, K1d, for Cd2+are 62.04 min-1 (untreated), 67.01 min-1 (treated with 0.5 mol/L mercaptoacetic acid), and 71.43 min-1(treated with 1.0 mol/L mercaptocacetic acid) while those for Cr3+ are 63.41 min-1 (untreated), 65.79 min-1(0.5 mol/L acid treated), and 66.25 min-1 (1.0 mol/L acid treated).

  11. Kinetic study on adsorption of Cr(VI), Ni(II), Cd(II) and Pb(II) ions from aqueous solutions using activated carbon prepared from Cucumis melo peel

    Science.gov (United States)

    Manjuladevi, M.; Anitha, R.; Manonmani, S.

    2018-03-01

    The adsorption of Cr(VI), Ni(II), Cd(II) and Pb(II), ions from aqueous solutions by Cucumis melo peel-activated carbon was investigated under laboratory conditions to assess its potential in removing metal ions. The adsorption behavior of metal ions onto CMAC was analyzed with Elovich, intra-particle diffusion rate equations and pseudo-first-order model. The rate constant of Elovich and intra-particle diffusion on CMAC increased in the sequence of Cr(VI) > Ni(II) > Cd(II) > Pb(II). According to the regression coefficients, it was observed that the kinetic adsorption data can fit better by the pseudo-first-order model compared to the second-order Lagergren's model with R 2 > 0.957. The maximum adsorption of metal ions onto the CMAC was found to be 97.95% for Chromium(VI), 98.78% for Ni(II), 98.55% for Pb(II) and 97.96% for Cd(II) at CMAC dose of 250 mg. The adsorption capacities followed the sequence Ni(II) ≈ Pb(II) > Cr(VI) ≈ Cd(II) and Ni(II) > Pb(II) > Cd(II) > Cr(VI). The optimum adsorption conditions selected were adsorbent dosage of 250 mg, pH of 3.0 for Cr(VI) and 6.0 for Ni(II), Cd(II) and Pb(II), adsorption concentration of 250 mg/L and contact time of 180.

  12. Analysis of Pb, Cd, Cr and Ni concentrations in types of cabbage marketed in Hamedan City

    Directory of Open Access Journals (Sweden)

    S Sobhanardakani

    2015-02-01

    Full Text Available Today, due to the accumulation of heavy metals in vegetables irrigated with wastewater and treated with sewage sludge has become increasing concern in the field of food safety and health of consumers. Therefore this study was conducted for analysis of Pb, Cd, Cr and Ni concentrations of 3 types of cabbage marketed in Hamedan City during 2013. For this purpose after buying 30 samples of each species of cabbage and then acid digestion of the samples according to standard methods, elements (Pb, Cd, Cr and Ni were determined using ICP-OES (Varian, 710-ES, Australia. All statistical analyses were performed using the SPSS statistical package. The results showed that mean concentrations of Pb, Cd, Cr and Ni in Cabbage samples were 15.53±3.43, 59.33±5.35, 2.22±1.61 and 14.97±2.83 mg/kg, respectively; mean concentrations of these elements in red cabbage samples were 23.03±5.89, 37.53±4.21, 13.33±3.24 and 15.03±3.04 mg/kg, respectively; and mean concentrations of elements in broccoli samples were 8.00±3.63, 45.90±5.86, 8.20±3.39 and 16.93±3.08 mg/kg, respectively. Also comparison of the mean concentrations of evaluated metals in specimens with FAO/WHO permissible limits showed that significant difference (p

  13. Complex investigation of several silver-less brazed Be/CuCrZr joints

    Energy Technology Data Exchange (ETDEWEB)

    Komarov, A.; Gervash, A.; Komarov, V.; Mazul, I.; Litounovski, N. [Efremov Inst., St Petersburg (Russian Federation); Fedotov, V.; Sevrukov, O. [Moscow Physical Engineering Inst. (Russian Federation); Ganenko, A. [CRISM Prometey, St Petersburg (Russian Federation)

    1998-07-01

    One of the main problems for ITER divertor target technology is to provide a reliable joint between Be as armour material and copper alloy as heat-sink structure. Such joints should satisfy the different requirements. In particular, these joints should successfully withstand cyclic heat fluxes and should have good properties under neutron irradiation. To study such complex of problems several investigation stages were planned in Russia. This paper presents the results of complex investigation of several silver-less brazed Be/CuCrZr joint candidates. (author)

  14. Complex investigation of several silver-less brazed Be/CuCrZr joints

    International Nuclear Information System (INIS)

    Komarov, A.; Gervash, A.; Komarov, V.; Mazul, I.; Litounovski, N.; Fedotov, V.; Sevrukov, O.; Ganenko, A.

    1998-01-01

    One of the main problems for ITER divertor target technology is to provide a reliable joint between Be as armour material and copper alloy as heat-sink structure. Such joints should satisfy the different requirements. In particular, these joints should successfully withstand cyclic heat fluxes and should have good properties under neutron irradiation. To study such complex of problems several investigation stages were planned in Russia. This paper presents the results of complex investigation of several silver-less brazed Be/CuCrZr joint candidates. (author)

  15. Application of atomic absorption spectrophotometry to determine Cd, Cu, Pb, Zn,...in vegetable samples in Dalat

    Energy Technology Data Exchange (ETDEWEB)

    Giang, Nguyen; Tam, Nguyen Thanh; Ngoc Trinh, Le Thi; Mai, Truong Phuong; Minh, Nguyen Van [Nuclear Research Institute, Dalat (Viet Nam)

    2004-08-01

    Nowadays atomic absorption spectrometry has become valuable method for trace element analysis because high specificity; low detection litmus, easy to use; easy sample preparation, low investment and running costs... atomic absorption spectrometry is generally accepted as one the most suitable method for single - element analysis of trace elements in various kinds of materiel. In 2003, we applied flame - atomic absorption spectrometry for analyzing Ca, Cd, Cu, Pb, Zn...in vegetables and their extracted juices were collected form 11 locations of Dalat, including two kinds of vegetables (goods and safety) in both the summer and winter. Average concentration of Ca = 240 mg/kg wet, Cd = 0.035 mg/kg wet, Cu = 0.67 mg/kg wet, Mg = 131 mg/kg wet, Fe = 8.1/kg wet, Mn = 3.1/kg wet, Na = 3266 mg/kg wet, Pb = 0.345 mg/kg wet and Zn = 3.3 mg wet. In their extracted juices: Ca = 89 mg/kg wet, Cd = 0.008 mg/kg wet, Cu = 0.19 mg/kg wet, Mg = 43 mg/kg wet, Fe = 2.3 mg/kg wet, Mn = 0.61 mg/kg wet, Na = 971 mg/kg wet, Pb = 0.107 mg/kg wet and Zn = 0.65 mg/kg wet. (author)

  16. Application of atomic absorption spectrophotometry to determine Cd, Cu, Pb, Zn,...in vegetable samples in Dalat

    International Nuclear Information System (INIS)

    Nguyen Giang; Nguyen Thanh Tam; Le Thi Ngoc Trinh; Truong Phuong Mai; Nguyen Van Minh

    2004-01-01

    Nowadays atomic absorption spectrometry has become valuable method for trace element analysis because high specificity; low detection litmus, easy to use; easy sample preparation, low investment and running costs... atomic absorption spectrometry is generally accepted as one the most suitable method for single - element analysis of trace elements in various kinds of materiel. In 2003, we applied flame - atomic absorption spectrometry for analyzing Ca, Cd, Cu, Pb, Zn...in vegetables and their extracted juices were collected form 11 locations of Dalat, including two kinds of vegetables (goods and safety) in both the summer and winter. Average concentration of Ca = 240 mg/kg wet, Cd = 0.035 mg/kg wet, Cu = 0.67 mg/kg wet, Mg = 131 mg/kg wet, Fe = 8.1/kg wet, Mn = 3.1/kg wet, Na = 3266 mg/kg wet, Pb = 0.345 mg/kg wet and Zn = 3.3 mg wet. In their extracted juices: Ca = 89 mg/kg wet, Cd = 0.008 mg/kg wet, Cu = 0.19 mg/kg wet, Mg = 43 mg/kg wet, Fe = 2.3 mg/kg wet, Mn = 0.61 mg/kg wet, Na = 971 mg/kg wet, Pb = 0.107 mg/kg wet and Zn = 0.65 mg/kg wet. (author)

  17. Thermodynamic studies on the adsorption of Cu2+, Ni2+ and Cd2+ ...

    African Journals Online (AJOL)

    Amine-modified bentonite (TEPA-Bn) has been prepared with tetraethylenepentamine (TEPA) as a modifier. The structure of Ca-based bentonite (Ca-Bn), TEPA-Bn and TEPA-Bn after adsorbing Cu2+,Ni2+,Cd2+ had been characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and ...

  18. Ab initio study of cubic complex Bi2CrCuO6 perovskite

    International Nuclear Information System (INIS)

    Fajardo, F.; Cardona, R.; Landinez Tellez, D.A.; Arbey Rodriguez M, J.; Roa-Rojas, J.

    2008-01-01

    We report a detailed calculation of the structural and electronic properties for the cubic complex Bi 2 CrCuO 6 perovskite material by density functional theory. The exchange-correlation potential was included through the generalized gradient approximation. From the adjusting of Murnaghan state equation to the energy as a function of volume data, we obtain an ideal lattice parameter of 7.763 A. The density of states study was carried out considering the two spin polarizations. Results reveal that this material behaves as a conductor to the spin-down polarization and evidence a semiconductor tendency to the spin-up configuration. This tendency to the half-metallicity character is corroborated by the integer number of magnetic moment (3.0 μ B ), which is attributed to the Cr-spin-up orbital contribution

  19. Room temperature ferromagnetism in magic-sized Cr-doped CdS diluted magnetic semiconducting quantum dots

    International Nuclear Information System (INIS)

    Srivastava, Punita; Kumar, Pushpendra; Singh, Kedar

    2011-01-01

    Manipulation of carrier spins in semiconductors for spintronics applications has received great attention driven by improved functionalities and higher speed operation. Doping of semiconductor nanocrystals by transition-metal ions pronounced as diluted magnetic semiconductors (DMS) has attracted tremendous attention. Such doping is, however, difficult to achieve in low-dimensional strongly quantum-confined nanostructures by conventional growth procedures. In the present case, magic-sized, pure, and Cr-doped CdS DM-QDs have been synthesized by solution phase chemistry (lyothermal method). Structural, optical, and magnetic investigation suggest an intrinsic nature of ferromagnetism with highly quantum-confined system. Optical and magnetic results of pure and doped QDs reveal major physical consequences of dopant localization within the capacity to engineer dopant-carrier exchange interactions introducing magnetic functionalities within the host semiconductor lattice. Unpaired Cr ions in Cd substitutional sites could create spin ordering and ferromagnetic coupling. The results presented herein illustrate some of the remarkable and unexpected complexities that can arise in doped QDs.

  20. Disponibilidade e fracionamento de Cd, Pb, Cu e Zn em função do pH e tempo de incubação com o solo Availability and fractionation of Cd, Pb, Cu, AND Zn in soil as a function of incubation time and pH

    Directory of Open Access Journals (Sweden)

    Évio Eduardo Chaves de Melo

    2008-06-01

    Full Text Available O pH e o tempo de contato influenciam a distribuição dos metais entre frações do solo e a eficiência da fitoextração. Objetivou-se, neste trabalho estudar a disponibilidade dos metais Cd, Pb, Cu e Zn para a fitoextração, bem como suas redistribuições no solo, em função do tempo de incubação em solo com e sem calagem. O solo recebeu Cd, Pb, Cu e Zn nas doses 20, 150, 100 e 150 mg kg-1, respectivamente, na forma de sal solúvel. As amostras foram incubadas por 210, 180, 150, 120, 90, 60, 30 e 0,5 dia. Terminada a incubação, mucuna preta (Stizolobium aterrimum Piper & Tracy foi cultivada por 30 dias. EDTA (10 mmol kg-1 foi aplicado sete dias, antes da coleta das plantas. As amostras de solo foram submetidas à extração química e fracionada. A concentração de metais pesados e a calagem afetaram a produção de matéria seca da parte aérea e da raiz. Em solos sem calagem, o aumento da solubilidade dos metais aumentou a fitoextração de Cd e Zn, mesmo sem aplicação do EDTA. A aplicação do EDTA ao solo com calagem mostrou-se eficiente para a fitoextração de Pb e Cu. A calagem reduziu os teores disponíveis de Cd, Pb, Cu e Zn. A calagem provocou redução nos teores de Cd, Pb, Cu e Zn trocáveis e aumento nas frações matéria orgânica, óxidos de ferro amorfo e cristalino.It is known that pH and incubation time influence the distribution of metals into soil fractions and therefore affect phytoextraction. Taking this in account, the aim of this work was to study the fractionation and availability of heavy metals for phytoextraction, as a function of incubation period in soils with or without liming. The soil samples were applied to Cd, Pb, Cu, and Zn at concentrations of 20, 150, 100, and 150 mg kg-1, respectively, in the form of soluble salt. The samples were kept incubated for high incubation periods: 210, 180, 150, 120, 90, 60, 30, and 0,5 day. After that, velvetbean (Stizolobium aterrimum Piper & Tracy was cultivated

  1. Heavy metals (Cd, Pb, Cu, Zn) in mudfish and sediments from three ...

    African Journals Online (AJOL)

    driniev

    2004-04-02

    Apr 2, 2004 ... and analysed for Cd and Pb by electro-thermal AAS, and for Cu and Zn by flame AAS. ... measurements and the dolomitic hard water and high pH of the Mooi River water .... Copper and zinc were determined by flame analysis at 324.8 nm ... were placed separately in clean 20 ml glass vials and one ml de-.

  2. Enriquecimiento, disponibilidad y contaminación de metales traza (Cd, Cu, Pb y Zn) en sedimentos de lagunas urbanas de Concepción-Chile Enrichment, availability and contamination of trace metals (Cd, Cu, Pb and Zn) in sediments of urban lagoons in Concepción, Chile

    OpenAIRE

    Elizabeth González Sepúlveda; María Retamal Cifuentes; Valentina Medina Pedreros; Ramón Ahumada Bermúdez; José Neira Hinojosa

    2009-01-01

    Trace metals (Cd, Cu, Pb and Zn) enrichment, availability and contamination in superficial sediments of three interconnected urban lagoons localized in Concepción-Chile, were evaluated. According to the results of geochemical fracctionation analysis, Cu and Pb are rather associated with oxi-hydroxides, Cd is associated with exchangeable and carbonates fraction, while Zn is mainly associated with organic, oxi-hydroxides and residual fraction. The estimation of the availability percentages indi...

  3. Superconducting Cd and Ca doped 123 phase in Cdo.8Ba2(Y0.7Ca0.4) Cu3.5Oy

    International Nuclear Information System (INIS)

    Balchev, N.; Kovachev, V; THOMAS, J.; BIEGER, W.; Konstantinov, K.; Kunev, B.

    1999-01-01

    A new Cd-containing superconductor with nominal composition of Cd 0.8 Ba 2 (Y 0.7 Ca 0.4 ) Cu 3.5 O y and T c = 80 K was synthesized and investigated. The obtained XRD pattern shows that the dominating phase is an orthorhombic 123. It was shown that the presence of Cd and Ca facilitates the 123 phase formation. The results of the EDX analysis on SEM and TEM have shown that the distribution of the Cd and Ca in the samples is inhomogeneous. The two elements enter the 123 phase in most of the investigated crystals and form a new Cd-Ba-Y-Ca-Cu-O superconducting compound

  4. Study on the application of magnesium oxide adsorptive compound to preconcentrate trace elements (As, Cu, Co, Cr, Hg, Mn, Sb and Zn) in high salt water and neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Giang, Nguyen; Tam, Nguyen Thanh; Phuong Mai, Truong Thi; Ho Tran The Huu [Center for Analytical Techniques, Nuclear Research Institute, Dalat (Viet Nam)

    2007-12-15

    The project presents preconcentration neutron activation analysis techniques for determination of trace metals (As, Co, Cr Cu, Hg, Mn, Sb and Zn) in high salt water by adsorption of trace metals on magnesium oxide. Precipitate is collected on 0.45 {mu}m membrane filters and irradiated in pneumatic rabit system and Lazy Susan facility at flux 5.10{sup 12} n/cm{sup 2}.sec for As, Cu, Mn and 2.10{sup 12} n/cm{sup 2}.sec for Hg, Sb, Cr, Co and Zn. The radioactivities of {sup 76}As, {sup 60}Co, {sup 64}Cu, {sup 51}Cr, {sup 203}Hg, {sup 56}Mn, {sup 124}Sb and {sup 65}Zn were measured. {sup 76}As, {sup 60}Co, {sup 64}Cu, {sup 51}Cr, {sup 203}Hg, {sup 56}Mn, {sup 124}Sb and {sup 65}Zn radio traces were used to establish optimum conditions and to evaluate the chemical yield. Detection limits of this method are 0.019, 0.006, 0.044, 0.058, 0.021, 0.027, 0.012 and 0.094 {mu}g of As, Co, Cr, Cu, Hg, Mn, Sb and Zn respectively. (author)

  5. Size effect on the SHG properties of Cu-doped CdI{sub 2} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M. Idrish, E-mail: m.miah@griffith.edu.au [Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)

    2009-12-15

    Because the optically induced second harmonic generation (SHG) is prevented by symmetry in a centrosymmetric material, one needs to form noncentrosymmetric processes in order to observe the SHG. However, one of the efficient ways to enhance the noncentrosymmetricity of a material is to dope it with an appropriate impurity and amount. We grow Cu-doped CdI{sub 2} layered nanocrystal structures from the mixture of CdI{sub 2} and CuI using the standard Bridgman-Stockbarger method and investigate the nano-confined effects by studying the second-order optical effect via the measurements of SHG. The second-order susceptibility for the nanocrystals is calculated and the values at liquid helium temperature range from 0.38 to 0.83 pm V{sup -1} for the thicknesses of 10-0.8 nm respectively. The size dependence demonstrates the nano-sized quantum-confined effect with a clear increase in the SHG with decreasing the thickness of the nanocrystal or crystal temperature. Since the local electron-phonon anharmonicity is described by third-order rank tensors in disordered systems, the SHG is very similar to that one introduced for the third-order optical susceptibility. It has been confirmed by observing the large photoluminescent yield of the pure crystals. The Raman scattering spectra taken for thin nanocrystals confirm the phonon modes originating from interlayer phonons crucially responsible for the observed effects. The obtained results show that the Cu-doped CdI{sub 2} layered nanocrystals are promising materials for applications in optoelectronic nano-devices.

  6. An experimental and thermodynamic equilibrium investigation of the Pb, Zn, Cr, Cu, Mn and Ni partitioning during sewage sludge incineration.

    Science.gov (United States)

    Liu, Jingyong; Fu, Jiewen; Ning, Xun'an; Sun, Shuiyu; Wang, Yujie; Xie, Wuming; Huang, Shaosong; Zhong, Sheng

    2015-09-01

    The effects of different chlorides and operational conditions on the distribution and speciation of six heavy metals (Pb, Zn, Cr, Cu, Mn and Ni) during sludge incineration were investigated using a simulated laboratory tubular-furnace reactor. A thermodynamic equilibrium investigation using the FactSage software was performed to compare the experimental results. The results indicate that the volatility of the target metals was enhanced as the chlorine concentration increased. Inorganic-Cl influenced the volatilization of heavy metals in the order of Pb>Zn>Cr>Cu>Mn>Ni. However, the effects of organic-Cl on the volatility of Mn, Pb and Cu were greater than the effects on Zn, Cr and Ni. With increasing combustion temperature, the presence of organic-Cl (PVC) and inorganic-Cl (NaCl) improved the transfer of Pb and Zn from bottom ash to fly ash or fuse gas. However, the presence of chloride had no obvious influence on Mn, Cu and Ni. Increased retention time could increase the volatilization rate of heavy metals; however, this effect was insignificant. During the incineration process, Pb readily formed PbSiO4 and remained in the bottom ash. Different Pb compounds, primarily the volatile PbCl2, were found in the gas phase after the addition of NaCl; the dominant Pb compounds in the gas phase after the addition of PVC were PbCl2, Pb(ClO4)2 and PbCl2O4. Copyright © 2015. Published by Elsevier B.V.

  7. Effect of Cu addition on microstructure and mechanical properties of 15%Cr super martensitic stainless steel

    International Nuclear Information System (INIS)

    Ye, Dong; Li, Jun; Jiang, Wen; Su, Jie; Zhao, Kunyu

    2012-01-01

    Highlights: ► Cu contributes to refine the grains. ► Cu solutes in matrix under quenching and precipitates as ε-Cu during tempering. ► Cu promotes the kinetics of reversed austenite formation. ► Mechanical properties are significantly influenced by austenite amount. ► Cu alloyed super martensitic stainless steel exhibits greatly improved mechanical properties. -- Abstract: The effect of adding different content of Cu (0 wt.%, 1.5 wt.% and 3 wt.%) to the 15%Cr super martensitic stainless steel (SMSS) was investigated using optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Its consequence on mechanical properties was examined to clarify the role of Cu in the tested steels. The experimental results indicate that the microstructures of three tested steels are tempered martensite, retained austenite and reversed austenite; two kinds of austenites are dispersedly distributed among martensite matrix. Cu can solute in matrix under quenching condition and can precipitate as Cu-rich nanometer phase (ε-Cu) during tempering. Cu is helpful for the grain refinement and to promote the formation of reversed austenite during tempering. The maximum volume fraction of austenite is 55.9% in the steel with 3 wt.% Cu, which is responsible for the improvement of ductility. The results of the mechanical properties tests reveal that the mechanical properties are significantly influenced by the volume fraction of austenite. Cu can cause solid solution strengthening, precipitation strengthening and grain refinement strengthening in SMSS. Cu alloyed super martensitic stainless steel exhibits greatly improved mechanical properties.

  8. Results of high heat flux testing of W/CuCrZr multilayer composites with percolating microstructure for plasma-facing components

    International Nuclear Information System (INIS)

    Greuner, Henri; Zivelonghi, Alessandro; Böswirth, Bernd; You, Jeong-Ha

    2015-01-01

    Highlights: • Improvement of the performance of plasma-facing components made of W and CuCrZr. • Functionally graded composite at the interface of W and CuCrZr to mitigate the CTE. • A three-layer composite system (W volume fraction: 70/50/30%) was developed. • Design of water-cooled divertor components up to 20 MW/m"2 heat load for e.g. DEMO. • HHF tests up to 20 MW/m"2 were successfully performed. - Abstract: Reliable joining of tungsten to copper is a major issue in the design of water-cooled divertor components for future fusion reactors. One of the suggested advanced engineering solutions is to use functionally graded composite interlayers. Recently, the authors have developed a novel processing route for fabricating multi-layer graded W/CuCrZr composites. Previous characterization confirmed that the composite materials possess enhanced strength compared to the matrix alloy and shows reasonable ductility up to 300 °C indicating large potential to extend the operation temperature limit. Furthermore, a three-layer composite system (W volume fraction: 70/50/30%) was developed as a graded interlayer between the W armour and CuCrZr heat sink. In this study, we investigated the structural performance of the graded joint. Three water-cooled mock-ups of a flat tile type component were fabricated using electron beam welding and thermally loaded at the hydrogen neutral beam test facility GLADIS. Cycling tests at 10 MW/m"2 and screening tests up to 20 MW/m"2 were successfully performed and confirmed the expected thermal performance of the compound. The measured temperature values were in good agreement with the prediction of finite element analysis. Microscopic investigation confirmed the structural integrity of the newly developed functionally graded composite after these tests.

  9. Results of high heat flux testing of W/CuCrZr multilayer composites with percolating microstructure for plasma-facing components

    Energy Technology Data Exchange (ETDEWEB)

    Greuner, Henri, E-mail: henri.greuner@ipp.mpg.de; Zivelonghi, Alessandro; Böswirth, Bernd; You, Jeong-Ha

    2015-10-15

    Highlights: • Improvement of the performance of plasma-facing components made of W and CuCrZr. • Functionally graded composite at the interface of W and CuCrZr to mitigate the CTE. • A three-layer composite system (W volume fraction: 70/50/30%) was developed. • Design of water-cooled divertor components up to 20 MW/m{sup 2} heat load for e.g. DEMO. • HHF tests up to 20 MW/m{sup 2} were successfully performed. - Abstract: Reliable joining of tungsten to copper is a major issue in the design of water-cooled divertor components for future fusion reactors. One of the suggested advanced engineering solutions is to use functionally graded composite interlayers. Recently, the authors have developed a novel processing route for fabricating multi-layer graded W/CuCrZr composites. Previous characterization confirmed that the composite materials possess enhanced strength compared to the matrix alloy and shows reasonable ductility up to 300 °C indicating large potential to extend the operation temperature limit. Furthermore, a three-layer composite system (W volume fraction: 70/50/30%) was developed as a graded interlayer between the W armour and CuCrZr heat sink. In this study, we investigated the structural performance of the graded joint. Three water-cooled mock-ups of a flat tile type component were fabricated using electron beam welding and thermally loaded at the hydrogen neutral beam test facility GLADIS. Cycling tests at 10 MW/m{sup 2} and screening tests up to 20 MW/m{sup 2} were successfully performed and confirmed the expected thermal performance of the compound. The measured temperature values were in good agreement with the prediction of finite element analysis. Microscopic investigation confirmed the structural integrity of the newly developed functionally graded composite after these tests.

  10. Efeito de ZN, Cd e Cu no comportamento de fungos ectomicorrízicos em meio de cultura

    Directory of Open Access Journals (Sweden)

    P. H. Grazziotti

    2001-12-01

    Full Text Available Os fungos ectomicorrízicos são capazes de tolerar concentrações de metais pesados tóxicas às plantas hospedeiras, apesar de serem adversamente influenciados pelo excesso de alguns metais. Avaliou-se o crescimento de um isolado de Pisolithus tinctorius e outro de Suillus bovinus em meio de cultura líquido com doses crescentes de sais de Zn, Cu ou Cd adicionados individualmente em frascos de 125 mL que continham 50 mL de meio Mellin-Norkrans modificado (MNM, em pH 4,8. Os fungos cresceram por 20 dias em câmara de crescimento a 28ºC. O crescimento dos fungos foi inibido com a elevação das concentrações dos metais, porém de forma diferenciada. As concentrações suficientes para inibir 50% do crescimento foram de 2,71 x 10-3 mol L-1 de Zn, 1,18 x 10-3 mol L-1 de Cu e 12,2 x 10-6 mol L-1 de Cd, para o P. tinctorius, e de 2,15 x 10-3 mol L-1 de Zn, 0,12 x 10-3 mol L-1 de Cu e 7,2 x 10-6 mol L-1 de Cd, para o S. bovinus. O efeito inibitório dos metais sobre o crescimento dos fungos seguiu a seguinte ordem decrescente: Cd > Cu > Zn. O isolado de S. bovinus apresentou tolerância ao Zn similar à observada para o P. tinctorius, mas foi menos tolerante que este em relação aos outros dois metais. O crescimento de P. tinctorius foi favorecido por pequena dose de Cu. A produção de pigmentos extracelulares nestes isolados foi estimulada por todos os metais estudados. O P. tinctorius, o mais tolerante, produziu mais pigmentos extracelulares por grama de micélio, o que sugere a relação positiva entre a capacidade de produção de pigmentos e a tolerância aos metais.

  11. Electron microscopy characterization of mechanically alloyed and hot consolidates Cu-Cr3C2 particles

    Directory of Open Access Journals (Sweden)

    López, M.

    2005-08-01

    Full Text Available Mechanically alloyed copper-ceramic composites have been obtained with the purpose of studying their use as copper-based material for electrical equipment. For high-temperature applications, dispersion-strengthened copper alloys are attractive due to their excellent combination of thermal and electrical conductivity, mechanical strength retention and microstructural stability. In this work, powder mixtures of pure copper with 2 vol % Cr3C2, milled during 4, 6, 10, 12 and 15 h in a high-energy planetary balls mill under argon atmosphere, were consolidated by hot isostatic pressing, applying a pressure of 100 MPa at 1073 K for two hours, to obtain materials with a fine microstructure. The Cu-Cr3C2 alloys were studied by scanning electron microscopy (SEM, electron microprobe (EPMA and transmission electron microscopy (TEM. Mechanical properties and electrical conductivity were also studied. The average tensile strength and electrical conductivity were found to be 500 MPa and 50 % IACS, respectively. The Cr3C2 ceramics show good stability during hot consolidation. Contributing to a further strengthening of the alloy during the hot consolidation, uniformly-distributed Fe-carbide particles of nanometric size precipitated in the copper matrix. Fe-Cr oxycarbides formed in the interphase between Cr3C2 particles and the copper matrix cause the low ductility of Cu-Cr3C2 alloys. Said particles are attributed to impurities/contamination generated from the milling process.

    Se obtuvieron aleaciones compuestas de Cu-Cr3C2, aleadas mecánicamente, para estudiar futuras aplicaciones en componentes eléctricos. A altas temperaturas, las aleaciones de base cobre reforzadas por dispersión, son atractivas por su excelente conductividad térmica y eléctrica, propiedades mecánicas y estabilidad microstructural. En este estudio

  12. Speciation and behaviour of Cd, Pb and Cu in Zuari Estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    George, M.D.

    Dissolved labile and nonlabile forms of Cd, Pb and Cu in Zuari Estuary, Goa, India measured for a period of 14 months showed lowest concentrations during the SW monsoon (June-September) while maximum concentrations were observed during...

  13. Subcellular metal partitioning in larvae of the insect Chaoborus collected along an environmental metal exposure gradient (Cd, Cu, Ni and Zn)

    Energy Technology Data Exchange (ETDEWEB)

    Rosabal, Maikel; Hare, Landis [Institut national de la Recherche scientifique, Centre Eau Terre Environnement (INRS-ETE), 490 de la Couronne, Quebec, Quebec, G1K 9A9 (Canada); Campbell, Peter G.C., E-mail: peter.campbell@ete.inrs.ca [Institut national de la Recherche scientifique, Centre Eau Terre Environnement (INRS-ETE), 490 de la Couronne, Quebec, Quebec, G1K 9A9 (Canada)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Midge larvae were collected from 12 lakes representing Cd, Cu, Ni and Zn gradients. Black-Right-Pointing-Pointer Along the gradients, the heat-stable protein fractions increased for Cd, Ni and Cu. Black-Right-Pointing-Pointer However, this metal detoxification response was incomplete for Cd and Ni. Black-Right-Pointing-Pointer Concentrations of these two metals increased in putative metal-sensitive fractions. Black-Right-Pointing-Pointer Metal detoxification is Chaoborus is compared to that in other freshwater animals. - Abstract: Larvae of the phantom midge Chaoborus are common and widespread in lakes contaminated by metals derived from mining and smelting activities. To explore how this insect is able to cope with potentially toxic metals, we determined total metal concentrations and subcellular metal partitioning in final-instar Chaoborus punctipennis larvae collected from 12 lakes situated along gradients in aqueous Cd, Cu, Ni and Zn concentrations. Concentrations of the non-essential metals Cd and Ni were more responsive to aqueous metal gradients than were larval concentrations of the essential metals Cu and Zn; these latter metals were better regulated and exhibited only 2-3-fold increases between the least and the most contaminated lakes. Metal partitioning was determined by homogenization of larvae followed by differential centrifugation, NaOH digestion and heat denaturation steps so as to separate the metals into operationally defined metal-sensitive fractions (heat-denaturable proteins (HDP), mitochondria, and lysosomes/microsomes) and metal-detoxified fractions (heat stable proteins (HSP) and NaOH-resistant or granule-like fractions). Of these five fractions, the HSP fraction was the dominant metal-binding compartment for Cd, Ni and Cu. The proportions and concentrations of these three metals in this fraction increased along the metal bioaccumulation gradient, which suggests that metallothionein-like proteins

  14. Water Soluble Cationic Porphyrin Sensor for Detection of Hg2+, Pb2+, Cd2+, and Cu2+

    Directory of Open Access Journals (Sweden)

    Matibur Zamadar

    2016-01-01

    Full Text Available Here we report the sensing properties of the aqueous solution of meso-tetra(N-methyl-4-pyridylporphine tetrachloride (1 for simultaneous detection of toxic metal ions by using UV-vis spectroscopy. Cationic porphyrin 1 displayed different electronic absorptions in UV-vis region upon interacting with Hg2+, Pb2+, Cd2+, and Cu2+ ions in neutral water solution at room temperature. Quite interestingly, the porphyrin 1 showed that it can function as a single optical chemical sensor and/or metal ion receptor capable of detecting two or more toxic metal ions, particularly Hg2+, Pb2+, and Cd2+ ions coexisting in a water sample. Porphyrin 1 in an aqueous solution provides a unique UV-vis sensing system for the determination of Cd2+ in the presence of larger metal ions such as Hg2+, or Pb2+. Finally, the examination of the sensing properties of 1 demonstrated that it can operate as a Cu2+ ion selective sensor via metal displacement from the 1-Hg2+, 1-Pb2+, and 1-Cd2+.

  15. Reduction of Cr(VI) to Cr(III) using silicon nanowire arrays under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Fellahi, Ouarda [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); Centre de Recherche en Technologie des Semi-conducteurs pour l' Energétique-CRTSE 02, Bd Frantz Fanon, BP. 140, Alger 7 Merveilles (Algeria); Barras, Alexandre [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); Pan, Guo-Hui [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Dong Nanhu Road, Changchun 130033 (China); Coffinier, Yannick [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); Hadjersi, Toufik [Centre de Recherche en Technologie des Semi-conducteurs pour l' Energétique-CRTSE 02, Bd Frantz Fanon, BP. 140, Alger 7 Merveilles (Algeria); Maamache, Mustapha [Laboratoire de Physique Quantique et Systèmes Dynamiques, Département de Physique, Université de Sétif, Sétif 19000 (Algeria); Szunerits, Sabine [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); and others

    2016-03-05

    Highlights: • Cr(VI) reduction to Cr(III) using silicon nanowires decorated with Cu nanoparticles. • The reduction takes place at room temperature and neutral pH under visible light. • The photocatalytic reduction was enhanced by addition of adipic or citric acid. - Abstract: We report an efficient visible light-induced reduction of hexavalent chromium Cr(VI) to trivalent Cr(III) by direct illumination of an aqueous solution of potassium dichromate (K{sub 2}Cr{sub 2}O{sub 7}) in the presence of hydrogenated silicon nanowires (H-SiNWs) or silicon nanowires decorated with copper nanoparticles (Cu NPs-SiNWs) as photocatalyst. The SiNW arrays investigated in this study were prepared by chemical etching of crystalline silicon in HF/AgNO{sub 3} aqueous solution. The Cu NPs were deposited on SiNW arrays via electroless deposition technique. Visible light irradiation of an aqueous solution of K{sub 2}Cr{sub 2}O{sub 7} (10{sup −4} M) in presence of H-SiNWs showed that these substrates were not efficient for Cr(VI) reduction. The reduction efficiency achieved was less than 10% after 120 min irradiation at λ > 420 nm. Addition of organic acids such as citric or adipic acid in the solution accelerated Cr(VI) reduction in a concentration-dependent manner. Interestingly, Cu NPs-SiNWs was found to be a very efficient interface for the reduction of Cr(VI) to Cr(III) in absence of organic acids. Almost a full reduction of Cr(VI) was achieved by direct visible light irradiation for 140 min using this photocatalyst.

  16. Fate of Cu, Cr, and As during combustion of impregnated wood with and without peat additive

    Energy Technology Data Exchange (ETDEWEB)

    Karin Lundholm; Dan Bostroem; Anders Nordin; Andrei Shchukarev [Umeaa University, Umeaa (Sweden). Energy Technology and Thermal Process Chemistry

    2007-09-15

    The EU Directive on incineration of waste regulates the harmful emissions of particles and twelve toxic elements, including copper, chromium, and arsenic. Using a 15 kW pellets-fueled grate burner, experiments were performed to determine the fate of copper, chromium, and arsenic during combustion of chromate copper arsenate (CCA) preservative wood. The fate and speciation of copper, chromium, and arsenic were determined from analysis of the flue gas particles and the bottom ash using SEM-EDS, XRD, XPS, and ICP-AES. Chemical equilibrium model calculations were performed to interpret the experimental findings. The results revealed that about 5% copper, 15% chromium, and 60% arsenic were volatilized during combustion of pure CCA-wood, which is lower than predicted volatilization from the individual arsenic, chromium, and copper oxides. This is explained by the formation of more stable refractory complex oxide phases for which the stability trends and patterns are presented. When co-combusted with peat, an additional stabilization of these phases was obtained and thus a small but noteworthy decrease in volatilization of all three elements was observed. The major identified phases for all fuels were CuCrO{sub 2}(s), (Fe,Mg,Cu)(Cr,Fe,Al)O{sub 4}(s), Cr{sub 2}O{sub 3}(s), and Ca{sub 3}(AsO{sub 4}){sub 2}(s). Arsenic was also identified in the fine particles as KH{sub 2}AsO{sub 4}(s) and As{sub 2}O{sub 3}). A strong indication of hexavalent chromium in the form of K{sub 2}CrO{sub 4} or as a solid solution between K{sub 3}Na(CrO{sub 4}){sub 2} and K{sub 3}Na(SO{sub 4}){sub 2} was found in the fine particles. Good qualitative agreement was observed between experimental data and chemical equilibrium model calculations. 38 refs., 6 figs., 2 tabs.

  17. Effects of copper concentration on electro-optical and structural properties of chemically deposited nanosized (Zn-Cd)S:Cu films

    International Nuclear Information System (INIS)

    Khare, Ayush

    2010-01-01

    Nanocrystalline (Zn-Cd)S films have been co-deposited on glass slide substrates by chemical bath deposition (CBD) technique at 70 deg. C for 75 min. Electroluminescent (EL), photoluminescent (PL) and structural characteristics of these films doped with Cu have been investigated. Cu doping has significant effects on the growth, structural and optical properties of the deposited (Zn-Cd)S films. EL studies show the essentiality of copper for EL emission. The effect of Cu concentration is examined on XRD, SEM, UV-vis spectroscopy, etc. The morphology of these films investigated with SEM and XRD is used to determine crystalline nature of the films. The optical absorption coefficient of the films has been found to increase with increase in Cu concentration. Voltage and frequency dependence shows the effectiveness of acceleration-collision mechanism. The trap-depth values are calculated from temperature dependence of EL brightness.

  18. Square-wave anodic-stripping voltammetric determination of Cd, Pb and Cu in wine: Set-up and optimization of sample pre-treatment and instrumental parameters

    International Nuclear Information System (INIS)

    Illuminati, Silvia; Annibaldi, Anna; Truzzi, Cristina; Finale, Carolina; Scarponi, Giuseppe

    2013-01-01

    For the first time, square-wave anodic-stripping voltammetry (SWASV) was set up and optimized for the determination of Cd, Pb and Cu in white wine after UV photo-oxidative digestion of the sample. The best procedure for the sample pre-treatment consisted in a 6-h UV irradiation of diluted, acidified wine, with the addition of ultrapure H 2 O 2 (three sequential additions during the irradiation). Due to metal concentration differences, separate measurements were carried out for Cd (deposition potential −950 mV vs. Ag/AgCl/3 M KCl deposition time 15 min) and simultaneously for Pb and Cu (E d −750 mV, t d 30 s). The optimum set-up of the main instrumental parameters, evaluated also in terms of the signal-to-noise ratio, were as follows: E SW 20 mV, f 100 Hz, ΔE step 8 mV, t step 100 ms, t wait 60 ms, t delay 2 ms, t meas 3 ms. The electrochemical behaviour was reversible bielectronic for Cd and Pb, and kinetically controlled monoelectronic for Cu. Good accuracy was found both when the recovery procedure was used and when the results were compared with data obtained by differential pulse anodic stripping voltammetry. The linearity of the response was verified up to ∼4 μg L −1 for Cd and Pb and ∼15 μg L −1 for Cu. The detection limits for t d = 5 min in the 10 times diluted, UV digested sample were (ng L −1 ): Cd 7.0, Pb 1.2 and Cu 6.6, which are well below currently applied methods. Application to a Verdicchio dei Castelli di Jesi white wine revealed concentration levels of Cd ∼0.2, Pb ∼10, Cu ∼30 μg L −1 with repeatabilities of (±RSD%) Cd ±6%, Pb ±5%, Cu ±10%

  19. Low-temperature solid-state preparation of ternary CdS/g-C_3N_4/CuS nanocomposites for enhanced visible-light photocatalytic H_2-production activity

    International Nuclear Information System (INIS)

    Cheng, Feiyue; Yin, Hui; Xiang, Quanjun

    2017-01-01

    Highlights: • CdS/g-C_3N_4/CuS composite were synthesized by low-temperature solid-state method. • CdS/g-C_3N_4/CuS show enhanced visible-light photocatalytic H_2 evolution activity. • The enhanced photocatalytic H_2 production activity is due to the heterojunction. • Heterojunction between the components promote charge separation/transfer property. - Abstract: Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C_3N_4/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C_3N_4/CuS composite exhibits a high visible-light photocatalytic H_2-production rate of 57.56 μmol h"−"1 with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na_2S/Na_2SO_3 mixed aqueous solution as sacrificial agent. The ternary CdS/g-C_3N_4/CuS composites show the enhanced visible-light photocatalytic H_2-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C_3N_4 in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H_2-production activity.

  20. Heavy metal (Cu, Zn, Cd and Pb) partitioning and bioaccessibility in uncontaminated and long-term contaminated soils

    International Nuclear Information System (INIS)

    Lamb, Dane T.; Ming Hui; Megharaj, Mallavarapu; Naidu, Ravi

    2009-01-01

    We investigated the pore-water content and speciation of copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) in a range of uncontaminated and long-term contaminated soils in order to establish their potential bioaccessibility to soil biota, plants and humans. Among the samples, soil pH (0.01 M CaCl 2 ) ranged from 4.9 to 8.2. The total metal content of the uncontaminated soils ranged from 3.8 to 93.8 mg Cu kg -1 , 10.3 to 95 mg kg -1 Zn, 0.1 to 1.8 mg Cd kg -1 and 5.2 to 183 mg kg -1 Pb, while metal content in the contaminated soils ranged from 104 to 6841 mg Cu kg -1 , 312 to 39,000 mg kg -1 Zn, 6 to 302 mg Cd kg -1 and 609 to 12,000 mg kg -1 Pb. Our analysis of pore-water found the Cu concentrations to be much higher in contaminated soils than in uncontaminated soils, with the distribution coefficients (K d ) correlating significantly with the log of dissolved organic carbon concentrations. Despite the high total metal content of the contaminated soil, Zn, Cd and Pb were not generally found at elevated levels in the pore-water with the exception of a single contaminated soil. A long period of ageing and soil weathering may have led to a substantial reduction in heavy metal concentrations in the pore-water of contaminated soils. On the other hand, Pb bioaccessibility was found to be comparatively high in Pb contaminated soils, where it tended to exceed the total Pb values by more than 80%. We conclude that, despite the extensive ageing of some contaminated soils, the bioaccessibility of Pb remains relatively high.

  1. Heavy metal (Cu, Zn, Cd and Pb) partitioning and bioaccessibility in uncontaminated and long-term contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Lamb, Dane T.; Ming Hui; Megharaj, Mallavarapu [Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), P.O. Box 486, Salisbury, SA 5106 (Australia); Naidu, Ravi, E-mail: ravi.naidu@crccare.com [Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), P.O. Box 486, Salisbury, SA 5106 (Australia)

    2009-11-15

    We investigated the pore-water content and speciation of copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) in a range of uncontaminated and long-term contaminated soils in order to establish their potential bioaccessibility to soil biota, plants and humans. Among the samples, soil pH (0.01 M CaCl{sub 2}) ranged from 4.9 to 8.2. The total metal content of the uncontaminated soils ranged from 3.8 to 93.8 mg Cu kg{sup -1}, 10.3 to 95 mg kg{sup -1} Zn, 0.1 to 1.8 mg Cd kg{sup -1} and 5.2 to 183 mg kg{sup -1} Pb, while metal content in the contaminated soils ranged from 104 to 6841 mg Cu kg{sup -1}, 312 to 39,000 mg kg{sup -1} Zn, 6 to 302 mg Cd kg{sup -1} and 609 to 12,000 mg kg{sup -1} Pb. Our analysis of pore-water found the Cu concentrations to be much higher in contaminated soils than in uncontaminated soils, with the distribution coefficients (K{sub d}) correlating significantly with the log of dissolved organic carbon concentrations. Despite the high total metal content of the contaminated soil, Zn, Cd and Pb were not generally found at elevated levels in the pore-water with the exception of a single contaminated soil. A long period of ageing and soil weathering may have led to a substantial reduction in heavy metal concentrations in the pore-water of contaminated soils. On the other hand, Pb bioaccessibility was found to be comparatively high in Pb contaminated soils, where it tended to exceed the total Pb values by more than 80%. We conclude that, despite the extensive ageing of some contaminated soils, the bioaccessibility of Pb remains relatively high.

  2. Effects of hydrazine on the solvothermal synthesis of Cu{sub 2}ZnSnSe{sub 4} and Cu{sub 2}CdSnSe{sub 4} nanocrystals for particle-based deposition of films

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Ming-Hung [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China); Fu, Yaw-Shyan, E-mail: ysfu@mail.nutn.edu.tw [Department of Greenergy, National University of Tainan, Tainan, Taiwan 700 (China); Shih, Cheng-Hung; Kuo, Chun-Cheng [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China); Guo, Tzung-Fang [Department of Photonics, Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan 701 (China); Lin, Wen-Tai, E-mail: wtlin@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China)

    2013-10-01

    The effects of hydrazine on the synthesis of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) and Cu{sub 2}CdSnSe{sub 4} (CCTSe) nanocrystals in an autoclave as a function of temperature and time were explored. On heating at 190 °C for 24-72 h, pure CZTSe and CCTSe nanocrystals could readily grow in the hydrazine-added solution, while in the hydrazine-free solution the intermediate phases such as ZnSe, Cu{sub 2}Se, and Cu{sub 2}SnSe{sub 3}, and Cu{sub 2}SnSe{sub 3} and CdSe associated with the CZTSe and CCTSe nanocrystals grew, respectively. This result reveals that hydrazine can speed up the synthesis of pure CZTSe and CCTSe nanocrystals via a solvothermal process. The mechanisms for the hydrazine-enhanced growth of CZTSe and CCTSe nanocrystals were discussed. The pure CZTSe and CCTSe nanocrystals were subsequently fabricated to the smooth films by spin coating without further annealing in selenium atmosphere. This processing may be beneficial to the fabrication of the absorber layer for solar cells and thermoelectric devices. - Highlights: • Hydrazine enhances the growth of pure Cu{sub 2}ZnSnSe{sub 4} and Cu{sub 2}CdSnSe{sub 4} nanocrystals. • The nanocrystals can be fabricated to films by spin coating without annealing. • This solvothermal processing is promising for the fabrication of thin film devices.

  3. Selective removals of heavy metals (Pb(2+), Cu(2+), and Cd(2+)) from wastewater by gelation with alginate for effective metal recovery.

    Science.gov (United States)

    Wang, Fei; Lu, Xingwen; Li, Xiao-yan

    2016-05-05

    A novel method that uses the aqueous sodium alginate solution for direct gelation with metal ions is developed for effective removal and recovery of heavy metals from industrial wastewater. The experimental study was conducted on Pb(2+), Cu(2+), and Cd(2+) as the model heavy metals. The results show that gels can be formed rapidly between the metals and alginate in less than 10 min and the gelation rates fit well with the pseudo second-order kinetic model. The optimum dosing ratio of alginate to the metal ions was found to be between 2:1 and 3:1 for removing Pb(2+) and around 4:1 for removing Cu(2+) and Cd(2+) from wastewater, and the metal removal efficiency by gelation increased as the solution pH increased. Alginate exhibited a higher gelation affinity toward Pb(2+) than Cu(2+) and Cd(2+), which allowed a selective removal of Pb(2+) from the wastewater in the presence of Cu(2+) and Cd(2+) ions. Chemical analysis of the gels suggests that the gelation mainly occurred between the metal ions and the -COO(-) and -OH groups on alginate. By simple calcination of the metal-laden gels at 700 °C for 1 h, the heavy metals can be well recovered as valuable resources. The metals obtained after the thermal treatment are in the form of PbO, CuO, and CdO nanopowders with crystal sizes of around 150, 50, and 100 nm, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Heavy metals (Cd, Cu, Ni and Pb) content in two fish species of ...

    African Journals Online (AJOL)

    GREGORY

    2010-09-13

    Sep 13, 2010 ... Water pollution and fish physiology. CRC press. Florida, USA, p. 245. Kalay M, Canli M (2000). Elimination of essential (Cu, Zn) and nonessential (Cd, Pb) metals from tissue of a freshwater fish Tilapia zillii following and uptake protocol. Turk. J. Zool. 24: 429-436. Karadede H, Ünlü E (2000). Concentrations ...

  5. The investigation of solid solutions thin interlayers in CdS/CdTe film heterosystems

    International Nuclear Information System (INIS)

    Khrypunov, G.; Boyko, B.; Chernykh, O.

    1999-01-01

    The photo-response spectral dependence of ITO/CdTe/Au/Cu and ITO/CdS/CdTe/Au/Cu film heterosystems were investigated. At illuminations ITO/CdS/CdTe/Au/Cu heterosystems on ITO side a photo-response maximum was observed for photon absorption with a wavelength of 0.87 μm that is stipulated by formation of CdS x Te 1-x solid solutions interlayer with band gap width less than in CdTe layer. By use optical measurement transmittance spectra was selected a spectral photosensitivity interval appropriate to the contribution of non-equilibrium charge carriers generated in solid solutions interlayer by photon absorption with energy less than CdTe film band gap

  6. Enhanced photocatalytic activity over Cd{sub 0.5}Zn{sub 0.5}S with stacking fault structure combined with Cu{sup 2+} modified carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Beini; Lu, Yonghong [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Wu, Pingxiao, E-mail: pppxwu@scut.edu.cn [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Guangdong Provincial Engineering and Technology Research Centre for Environment Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); Huang, Zhujian; Zhu, Yajie; Dang, Zhi [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Zhu, Nengwu [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Guangdong Provincial Engineering and Technology Research Centre for Environment Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); Lu, Guining; Huang, Junyi [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China)

    2016-03-01

    Graphical abstract: - Highlights: • CdZnS with stacking faults was combined with Cu{sup 2+} modified carbon nanotubes. • Stacking faults and carbon nanotubes (Cu) synergized to promote charge separation. • The composite exhibited enhanced photocatalytic performance. - Abstract: For enhanced photocatalytic performance of visible light responsive CdZnS, a series of Cd{sub 0.5}Zn{sub 0.5}S solid solutions were fabricated by different methods. It was found that the semiconductor obtained through the precipitation-hydrothermal method (CZS-PH) exhibited the highest photocatalytic hydrogen production rate of 2154 μmol h{sup −1} g{sup −1}. The enhanced photocatalytic hydrogen production of CZS-PH was probably due to stacking fault formation as well as narrow bandgap, a large surface area and a small crystallite size. Based on this, carbon nanotubes modified with Cu{sup 2+} (CNTs (Cu)) were used as a cocatalyst for CZS-PH. The addition of CNTs (Cu) enhanced notably the absorption of the composites for visible light. The highest photocatalytic hydrogen production rate of the Cd{sub 0.5}Zn{sub 0.5}S-CNTs (Cu) composite was 2995 μmol h{sup −1} g{sup −1} with 1.0 wt.% of CNTs (Cu). The improvement of the photocatalytic activity by loading of CNTs (Cu) was not due to alteration of bandgap energy or surface area, and was probably attributed to suppression of the electron-hole recombination by the CNTs, with Cu{sup 2+} anchored in the interface optimizing the photogenerated electron transfer pathway between the semiconductor and CNTs. We report here the successful combination of homojunction and heterojunction in CdZnS semiconductor, which resulted in promotion of charge separation and enhanced photocatalytic activity.

  7. Levels Of Mn, Fe, Ni, Cu, Zn And Cd, In Effluent From A Sewage ...

    African Journals Online (AJOL)

    This study reports the results of preliminary investigation of heavy metal levels-Ni, Cd, Fe, Zn, Cu and Mn; pH; temperature and electrical conductivity in effluents from a sewage treatment oxidation pond and its receiving stream. The heavy metal concentrations were determined with Inductively Coupled Plasma-Mass ...

  8. Slurry Erosion Behavior of Destabilized and Deep Cryogenically Treated Cr-Mn-Cu White Cast Irons

    Directory of Open Access Journals (Sweden)

    S. Gupta

    2016-12-01

    Full Text Available The effects of destabilization treatment and destabilization followed by cryogenic treatment have been evaluated on the microstructural evolution and sand-water slurry erosion behavior of Cr-Mn-Cu white cast irons. The phase transformations after the destabilization and cryotreatment have been characterized by bulk hardness measurement, optical and scanning electron microscopy, x-ray diffraction analysis. The static corrosion rate has been measured in tap water (with pH=7 and the erosion-corrosion behavior has been studied by slurry pot tester using sand-water slurry. The test results indicate that the cryogenic treatment has a significant effect in minimizing the as-cast retained austenite content and transforming into martensitic and bainitic matrix embedded with ultra-fine M7C3 alloy carbides. In contrast, by conventional destabilization treatment retained austenite in the matrix are not fully eliminated. The slurry erosive wear resistance has been compared with reference to destabilized and cryotreated high chromium iron samples which are commonly employed for such applications. The cryotreated Cr-Mn-Cu irons have exhibited a comparable erosive wear performance to those of high chromium irons. Higher hardness combined with improved corrosion resistance result in better slurry erosion resistance.

  9. Column dynamic studies and breakthrough curve analysis for Cd(II) and Cu(II) ions adsorption onto palm oil boiler mill fly ash (POFA).

    Science.gov (United States)

    Aziz, Abdul Shukor Abdul; Manaf, Latifah Abd; Man, Hasfalina Che; Kumar, Nadavala Siva

    2014-01-01

    This paper investigates the adsorption characteristics of palm oil boiler mill fly ash (POFA) derived from an agricultural waste material in removing Cd(II) and Cu(II) from aqueous solution via column studies. The performance of the study is described through the breakthrough curves concept under relevant operating conditions such as column bed depths (1, 1.5, and 2 cm) and influent metal concentrations (5, 10, and 20 mg/L). The Cd(II) and Cu(II) uptake mechanism is particularly bed depth- and concentration-dependant, favoring higher bed depth and lower influent metal concentration. The highest bed capacity of 34.91 mg Cd(II)/g and 21.93 mg Cu(II)/g of POFA was achieved at 20 mg/L of influent metal concentrations, column bed depth of 2 cm, and flow rate of 5 mL/min. The whole breakthrough curve simulation for both metal ions were best described using the Thomas and Yoon–Nelson models, but it is apparent that the initial region of the breakthrough for Cd(II) was better described using the BDST model. The results illustrate that POFA could be utilized effectively for the removal of Cd(II) and Cu(II) ions from aqueous solution in a fixed-bed column system.

  10. Induction and Maintenance of CX3CR1-Intermediate Peripheral Memory CD8+ T Cells by Persistent Viruses and Vaccines

    Directory of Open Access Journals (Sweden)

    Claire Louse Gordon

    2018-04-01

    Full Text Available Summary: The induction and maintenance of T cell memory is critical to the success of vaccines. A recently described subset of memory CD8+ T cells defined by intermediate expression of the chemokine receptor CX3CR1 was shown to have self-renewal, proliferative, and tissue-surveillance properties relevant to vaccine-induced memory. We tracked these cells when memory is sustained at high levels: memory inflation induced by cytomegalovirus (CMV and adenovirus-vectored vaccines. In mice, both CMV and vaccine-induced inflationary T cells showed sustained high levels of CX3R1int cells exhibiting an effector-memory phenotype, characteristic of inflationary pools, in early memory. In humans, CX3CR1int CD8+ T cells were strongly induced following adenovirus-vectored vaccination for hepatitis C virus (HCV (ChAd3-NSmut and during natural CMV infection and were associated with a memory phenotype similar to that in mice. These data indicate that CX3CR1int cells form an important component of the memory pool in response to persistent viruses and vaccines in both mice and humans. : Gordon et al. demonstrate that CX3CR1int peripheral memory T cells are a substantial component of memory inflation induced by persistent CMVs and adenoviral vaccination. They are characterized by sustained proliferation and an effector-memory phenotype linked to these expanded CD8+ T cell memory responses. Core phenotypic features are shared by humans and mice. Keywords: cytomegalovirus, T cells, memory, adenovirus, vaccination, CX3CR1, memory inflation, mouse, human

  11. Caracterización morfológica de películas delgadas de cu/cd obtenidas por electrodeposición

    Directory of Open Access Journals (Sweden)

    William Arnulfo Aperador-Chaparro

    2007-01-01

    Full Text Available This work presents the use of the technique of current pulsant inverse, pulse direct current and direct current for electrodeposition thin films Cu/Cd in double-layer shape on Zamak substrate. The influence of the different variables was studied involved in each one of the processes: voltage and time of deposition (VHigh and VLow, voltage and time of breakup (VLow and tLow and the load cycle ( =tHigh/tHigh+tLow, obtaining the average of the anodic (ILow and cathodic (IHigh currents as a function of the anodic (tLow and cathodic (tHigh times, respectively. The electrodeposits of Cu/Cd were characterized by means of optic microscopy to obtain the grain size; moreover the ruggedness was obtained using a Scanning Proved Image Processor (SPIP. These results showed that the control of pulsed voltage during the deposit allowing to obtain Cu/Cd films denser, and with a size of grain finer that the conventional films deposited by the technique of direct current. The protective anticorrosive power of the thin films was evaluated by means the technique TAFEL.

  12. Ferromagnetic half-metallic characteristic in bulk Ni 0.5M 0.5O (M=Cu, Zn and Cd): A GGAU study

    KAUST Repository

    Mi, Wenbo; Yang, Hua; Cheng, Yingchun; Bai, Haili

    2012-01-01

    Ferromagnetic half metallicity with a high spin polarization of 100% was predicted in the bulk Ni 0.5Cu 0.5O using density-functional theory method. The band gap of majority spin is 3.45 eV for Ni 0.5Cu 0.5O. The density of states of minority spin at the Fermi level are mainly from Cu 3d and O 2p in the Ni 0.5Cu 0.5O. The magnetic moments are from Ni 3d states. Ni 0.5Zn 0.5O and Ni 0.5Cd 0.5O systems are ferromagnetic insulators, but the magnetic moment of Ni 2 ions is enhanced by the Zn and Cd incorporation. Therefore, Ni 0.5Cu 0.5O is the potential candidate for spintronics devices because of the predicted high spin polarization. © 2012 Elsevier Ltd. All rights reserved.

  13. Ferromagnetic half-metallic characteristic in bulk Ni 0.5M 0.5O (M=Cu, Zn and Cd): A GGAU study

    KAUST Repository

    Mi, Wenbo

    2012-07-01

    Ferromagnetic half metallicity with a high spin polarization of 100% was predicted in the bulk Ni 0.5Cu 0.5O using density-functional theory method. The band gap of majority spin is 3.45 eV for Ni 0.5Cu 0.5O. The density of states of minority spin at the Fermi level are mainly from Cu 3d and O 2p in the Ni 0.5Cu 0.5O. The magnetic moments are from Ni 3d states. Ni 0.5Zn 0.5O and Ni 0.5Cd 0.5O systems are ferromagnetic insulators, but the magnetic moment of Ni 2 ions is enhanced by the Zn and Cd incorporation. Therefore, Ni 0.5Cu 0.5O is the potential candidate for spintronics devices because of the predicted high spin polarization. © 2012 Elsevier Ltd. All rights reserved.

  14. S, Zn, Cr, Cu and Fe changes during fluvial sediments oxidation Transformaciones del S, Zn, Cr, Cu y Fe en sedimentos fluviales durante el proceso de secado

    Directory of Open Access Journals (Sweden)

    María Pía Di Nanno

    2009-12-01

    Full Text Available Acidification of dredged sediments which have been disposed on land is highly dependent on redox shifts. The aim of the present work was to assess changes in sulphur, metal speciation (Zn, Fe, Cr y Cu and acidity caused by a polluted sediment oxidation event. Sediments were dessicated under controlled conditions and sulphide compounds (acid volatile sulphides-AVS- and sulphate, pH and neutralization potential were measured through time during 36 days. Zinc, Cu, Cr and Fe speciation (BCR metal sequential extraction procedure were measured at the beginning of the experiment and at day 22. An acid-base equilibrium method based on the BCR procedure was employed to assess the sediment acidification risk. Some of the re-suspension experiments were inoculated with an Acidithiobacillus ferrooxidans strain to assess biological catalysis on sulphide oxidation. Acid-base equilibrium results indicated the sediment sample had a significant acidification potential. Oxidation increased sulphate levels (56 to 2300 mg S kg-¹ in the desiccation experiment with a temporal evolution adjusted by a logistic model, and a 2100 to 3000 mg SO4 -² L-¹ increase for the resuspension experiments. Sulphide oxidation rates varied between 0 to 3.1.10-9 mg O2 kg-¹ s-¹ for the drying sediment. Zinc changes could be explained partially by ZnS conversion to ZnSO4 during oxidation. Iron reduction could be attributed to an increase in Fe oxides crystallinity. Acid-base equilibrium for the sample indicated it was a potentially acid-generating material. Zinc increased its bioavailability during drying and was the only metal that appeared in significant amounts in solution during re-suspension. Land-filling with dredged sediments could present increased metals bioavailability problems despite having an important and effective neutralization potential.La evaluación de los riesgos de acidificación por deposición de sedimentos dragados en superficie es muy dependiente de los

  15. Comparison of GRCop-84 to Other Cu Alloys with High Thermal Conductivities

    Science.gov (United States)

    deGroh, Henry C., III; Ellis, David L.; Loewenthal, William S.

    2007-01-01

    The mechanical properties of six highly conductive copper alloys, GRCop-84, AMZIRC, GlidCop Al-15, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z were compared. Tests were done on as-received hard drawn material, and after a heat treatment designed to simulate a brazing operation at 935 C. In the as-received condition AMZIRC, GlidCop Al-15, Cu- 1Cr-0.1Zr and Cu-0.9Cr had excellent strengths at temperatures below 500 C. However, the brazing heat treatment substantially decreased the mechanical properties of AMZIRC, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z. The properties of GlidCop Al-15 and GRCop-84 were not significantly affected by the heat treatment. Thus there appear to be advantages to GRCop-84 over AMZIRC, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z if use or processing temperatures greater than 500 C are expected. Ductility was lowest in GlidCop Al-15 and Cu-0.9Cr; reduction in area was particularly low in GlidCop Al-15 above 500 C, and as- received Cu-0.9Cr was brittle between 500 and 650 C. Tensile creep tests were done at 500 and 650 C; the creep properties of GRCop-84 were superior to those of brazed AMZIRC, Cu-1Cr- 0.1Zr, Cu-0.9Cr, and NARloy-Z. In the brazed condition, GRCop-84 was superior to the other alloys due to its greater strength and creep resistance (compared to AMZIRC, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z) and ductility (compared to GlidCop Al-15).

  16. Distribution and Behaviors of Cd, Cu, and Ni in the East China Sea Surface Water off the Changjiang Estuary

    Directory of Open Access Journals (Sweden)

    Kuo-Tung Jiann

    2009-01-01

    Full Text Available Trace metal (Cd, Cu, and Ni dis tri bu tions and be hav iors in sur face waters of the East China Sea continental shelf were investigated during an expeditioncon ducted in June 2004. Dissolved and particulate trace metal con centrations, as well as fractions of dissolved trace metals, fraction ated based on their different chemical affinities to ion exchangers, were determined using ultra-clean techniques and graphite furnace atomic absorption spectrometry (GFAAS. Large variations of dissolved (< 0.45 mm metal concentrations in the East China Sea shelf waters were found (n = 16 and ranged between 0.036 - 0.287 nM for Cd, 0.87 - 8.66 nM for Cu, and 2.66 - 6.04 nM for Ni. Particulate metal contributions were highest near the river mouth. Dis solved Cd and Ni were pre dominantly present (98% for Cd and 86% for Ni as Chelex-labile fractions in the shelf waters.

  17. Adsorption of Cu 2+ , As 3+ and Cd 2+ ions from aqueous solution ...

    African Journals Online (AJOL)

    The adsorption of Cu2+, Cd2+ and As3+ ions on eggshell from aqueous solution was studied under batch conditions at 30, 40, 50 and 60oC and concentrations of 10, 20, 30, 60 and 80 mg/l. The partition coefficient for the ions between aqueous solution and chicken eggshell increased with time and with increase in the ...

  18. Preparation and electrical properties of ZnO/CdS/Cu (In, Zn) Se2 (ZCIS) heterojunctions

    International Nuclear Information System (INIS)

    Ivanov, V.A.; Gremenok, V.F.; Zalesski, V.B.; Kovalevski, V.I.; Bente, K.

    2010-01-01

    Full text : Cu(In,Zn)Se 2 (ZCIS) is one of the most promising materials for commercial photovoltaic applications. This is due to the high absorption coefficient of approximately 105 cm - 1 in a wide spectral region and a band gap that is in principle adjustable between 1.05 eV for CuInSe 2 and 2.60 eV for ZnSe. Therefore they are suggested to be used in thin film solar cells as absorber as well a wide-gap window layers. The Cu/(In+Zn) ratio of the ZCIS layers is the important parameter for the physical properties of the semiconductor material as well for the solar cell applications. The presented results consider the preparation as well as the chemical, structural and physical characterization of the electrical properties of the ZnO/CdS/CuIn0, 94Zn0, 06Se2 thin films hetero junctions. The ZCIS films were prepared by two-step selenization of Cu-In-ZnSe layers under N2 flow by evaporating a solid Se source close to samples. Such technology is especially suited for developments of industrial processing of large area ZCIS films suitable for solar cells. Cu-In-ZnSe layers were deposited onto Mo-coated soda lime glass substrates by thermal evaporation or sputtering. The Zn content in the ZCIS films was controlled by choise of In/ZnSe ratio in the initial alloy. Buffer layers of CdS were deposited onto the ZCIS films in the chemical bath. The ZnO films were deposited onto CdS by thermal evaporation. The ZnO and CdS films were detected to be polycrystalline with thicknesses of 0.4im and 0.06im respectively and revealed n-type conductivity. The ''Leit-C'' conductive glue was used as electrical contacts. The effective area of each cell was about 0.8 cm2. Under non-illuminated conditions, I - V characteristics of the heterojunctions were approximately exponential at low voltages according to the standard diode equation I=Io[exp(eV/nkT)-1], with a slight deviation from this behaviour at high voltages due to a series of resistance effects. The capacitance of the heterojunctions

  19. First principles calculations of point defect diffusion in CdS buffer layers: Implications for Cu(In,Ga)(Se,S){sub 2} and Cu{sub 2}ZnSn(Se,S){sub 4}-based thin-film photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Varley, J. B.; Lordi, V. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); He, X.; Rockett, A. [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    2016-01-14

    We investigate point defects in CdS buffer layers that may arise from intermixing with Cu(In,Ga)Se{sub 2} (CIGSe) or Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) absorber layers in thin-film photovoltaics (PV). Using hybrid functional calculations, we characterize the migration barriers of Cu, In, Ga, Se, Sn, Zn, Na, and K impurities and assess the activation energies necessary for their diffusion into the bulk of the buffer. We find that Cu, In, and Ga are the most mobile defects in CIGS-derived impurities, with diffusion expected to proceed into the buffer via interstitial-hopping and cadmium vacancy-assisted mechanisms at temperatures ∼400 °C. Cu is predicted to strongly favor migration paths within the basal plane of the wurtzite CdS lattice, which may facilitate defect clustering and ultimately the formation of Cu-rich interfacial phases as observed by energy dispersive x-ray spectroscopic elemental maps in real PV devices. Se, Zn, and Sn defects are found to exhibit much larger activation energies and are not expected to diffuse within the CdS bulk at temperatures compatible with typical PV processing temperatures. Lastly, we find that Na interstitials are expected to exhibit slightly lower activation energies than K interstitials despite having a larger migration barrier. Still, we find both alkali species are expected to diffuse via an interstitially mediated mechanism at slightly higher temperatures than enable In, Ga, and Cu diffusion in the bulk. Our results indicate that processing temperatures in excess of ∼400 °C will lead to more interfacial intermixing with CdS buffer layers in CIGSe devices, and less so for CZTSSe absorbers where only Cu is expected to significantly diffuse into the buffer.

  20. Effects of Cr III and Pb on the bioaccumulation and toxicity of Cd in tropical periphyton communities: Implications of pulsed metal exposures

    International Nuclear Information System (INIS)

    Bere, Taurai; Chia, Mathias Ahii; Tundisi, José Galizia

    2012-01-01

    Metal exposure pattern, timing, frequency, duration, recovery period, metal type and interactions, has obscured effects on periphyton communities in lotic systems. The objective of this study was to investigate the effects of intermittent exposures of Cr III and Pb on Cd toxicity and bioaccumulation in tropical periphyton communities. Natural periphyton communities were transferred to artificial stream chambers and exposed to metal mixtures at different pulse timing, duration, frequency and recovery periods. Chlorophyll a, dry mass and metal accumulation kinetics were recorded. Cr and Pb decrease the toxic effects of Cd on periphyton communities. Periphyton has high Cd, Cr and Pb accumulation capacity. Cr and Pb reduced the levels of Cd sequestrated by periphyton communities. The closer the frequency and duration of the pulse is to a continuous exposure, the greater the effects of the contaminant on periphyton growth and metal bioaccumulation. Light increased toxic and accumulative effects of metals on the periphyton community. - Highlights: ► We investigated toxicity effects of pulsed metal exposures on bioaccumulation and toxicity in periphyton. ► High frequency of short duration pulses has effects equal to long duration exposures. ► Important role of light in modulating metal toxicity on periphyton demonstrated. ► Factors other than magnitude and duration must be considered in water quality criteria. ► Accurate prediction of metal effects on biofilms requires data on effluent variability. - The study highlights the importance of pulse timing, frequency, duration, recovery period and chemical type on aquatic life.

  1. Earthworm responses to Cd and Cu under fluctuating environmental conditions: a comparison with results from laboratory exposures

    International Nuclear Information System (INIS)

    Spurgeon, David J.; Svendsen, Claus; Lister, Lindsay J.; Hankard, Peter K.; Kille, Peter

    2005-01-01

    Laboratory toxicity tests are usually conducted under stable ambient conditions, while exposures in ecosystems occur in a fluctuating climate. To assess how climate influences the toxicity of Cu and Cd for the earthworm Lumbricus rubellus, this study compared effects for life-cycle parameters (survival, reproduction), cellular status (lysosomal membrane stability), gene expression (transcript of the metal binding protein metallothionein-2) and tissue metal concentration measured under outdoor conditions, with the same responses under constant conditions as measured by Spurgeon et al. [Spurgeon, D.J., Svendsen, C., Weeks, J.M., Hankard, P.K., Stubberud, H.E., Kammenga, J.E., 2003. Quantifying copper and cadmium impacts on intrinsic rate of population increase in the terrestrial oligochaete Lumbricus rubellus. Environmental Toxicology and Chemistry 22, 1465-1472]. Both metals were found to significantly influence earthworm reproduction, compromise lysosomal membrane stability and induce MT-2 gene expression in the outdoor system. Comparison with physiological and life-cycle responses in the laboratory indicated similar response patterns and effect concentrations for Cu. For Cd, lysosomal membrane stability and MT-2expression showed comparable responses in both exposures. Juvenile production rate, however, gave different dose response relationships, with the EC- 50 in the outdoor test approximately half that in the laboratory test. A difference in Cd accumulation was also seen. Overall, however, the comparison indicated only a marginal effect of environmental fluctuations typical for northern temperate Europe on earthworm sensitivity to the two metals. - Comparative analysis of life-cycle, physiological and molecular responses to Cu and Cd indicate similar responses under static and fluctuating climate regimes

  2. Study of Selected Metals Distribution, Source Apportionment, and Risk Assessment in Suburban Soil, Pakistan

    Directory of Open Access Journals (Sweden)

    Javed Iqbal

    2015-01-01

    Full Text Available Composite soil samples collected from suburban areas were analyzed for Cd, Co, Cr, Cu, Fe, Mn, Pb, Sr, and Zn by atomic absorption spectrophotometry. Based on pseudototal metal analysis, Fe, Mn, Sr, and Zn were the prevailing metals while Cd, Co, Cr, and Pb were the least participants. However, based on bioavailability, Cd, Co, Pb, and Sr were easily leachable and might pose adverse effects to soil biota. In ecological risk assessment, contamination factor demonstrated moderate contamination by Co, Sr, and Zn and high contamination by Cd, Cu, and Pb; geoaccumulation index indicated heavy to extreme contamination by Cd and heavy contamination by Pb; enrichment factor revealed significant enrichment by Co, Cr, Cu, Mn, Sr, and Zn and extreme enrichment by Cd and Pb. Substantial human inputs for Cd, Co, Cr, Cu, Mn, Pb, Sr, and Zn were also revealed by principal component analysis in the examined soil. Overall the study area was found to be contaminated at considerable/high degree.

  3. Excellent photocatalytic hydrogen production over CdS nanorods via using noble metal-free copper molybdenum sulfide (Cu2MoS4) nanosheets as co-catalysts

    Science.gov (United States)

    Hong, Sangyeob; Kumar, D. Praveen; Reddy, D. Amaranatha; Choi, Jiha; Kim, Tae Kyu

    2017-02-01

    Charge carrier recombination and durability issues are major problems in photocatalytic hydrogen (H2) evolution processes. Thus, there is a very important necessitate to extend an efficient photocatalyst to control charge-carrier dynamics in the photocatalytic system. We have developed copper molybdenum sulfide (Cu2MoS4) nanosheets as co-catalysts with CdS nanorods for controlling charge carriers without recombination for use in photocatalytic H2 evolution under simulated solar light irradiation. Effective control and utilization of charge carriers are possible by loading Cu2MoS4 nanosheets onto the CdS nanorods. The loading compensates for the restrictions of CdS, and stimulated synergistic effects, such as efficient photoexcited charge separation, lead to an improvement in photostability because of the layered structure of the Cu2MoS4nanosheets. These layered Cu2MoS4 nanosheets have emerged as novel and active replacements for precious noble metal co-catalysts in photocatalytic H2 production by water splitting. We have obtained superior H2 production rates by using Cu2MoS4 loaded CdS nanorods. The physicochemical properties of the composites are analyzed by diverse characterization techniques.

  4. On the metal-support synergy for selective gas-phase ethanol oxidation over MgCuCr2O4 supported metal nanoparticle catalysts

    NARCIS (Netherlands)

    Liu, P.; Zhu, X.; Yang, S.; Li, T.; Hensen, E.J.M.

    2015-01-01

    Achieving high yields in the production of bulk chemicals is an important goal for the chemical industry. We investigated the influence of the metal on the catalytic performance of M/MgCuCr2O4 (M = Cu, Ag, Pd, Pt, Au) catalysts to better understand the metal-support synergy for the aerobic oxidation

  5. Comparative strength analysis and thermal fatigue testing of Be/CuCrZr and Be/GlidCop joints produced by fast brazing

    International Nuclear Information System (INIS)

    Gervash, A.; Mazul, I.; Yablokov, N.; Barabash, V.; Ganenko, A.

    2000-01-01

    Proposing beryllium as plasma facing armour this paper presents the recent results obtained in Russia in the frame of such activities. Last year testing of actively cooled mock-ups produced by fast brazing of Be onto Cu-alloy heat sink allows to consider mentioned Russian method as promising for both PH-copper like CuCrZr and DS-copper like GlidCop. Summarizing recent experimental results with their previous data authors attempt to comparatively investigate a behaviour of Be/CuCrZr and Be/GlidCop joints in ITER relevant conditions. Mechanical properties, brazing zone microstructure and thermal response were taken for comparison. The shear strength for both types of joints was found as 150-200 MPa and did not depend on testing temperature. The brazing zone morphology and microhardness are presented, the thermal fatigue behaviour of investigated joints is described. All main results as well as the nearest future plans are discussed. (orig.)

  6. Remediation of Cu in the Contaminated Soil by Using Equisetum debile (Horsetail

    Directory of Open Access Journals (Sweden)

    Irna Rahmaniar

    2015-05-01

    Full Text Available Paddy fields in the Rancaekek area, Bandung Regency-Indonesia, has been contaminated by textile wastewater. The area needs to recover back to its normal condition and function. Several compounds were found in the soil, such as Cu, Zn, Pb, Cd, Co, Ni, and Cr. Phytoremediation was selected as a site remediation strategy, which employs plants to remove non-volatile and immiscible soil contents. The objective of the study was to determine the ability of Equisetum debile to absorb Cu from the contaminated soil. Cu measurement was conducted by using the AAS (Atomic Absorption Spectrophotometer method. The study has shown that Equisetum debile can absorb Cu concentrations of up to 25.3 ppm in 60 days after initial planting. However, the Enrichment Coefficient value (0.392 indicated that Equisetum debile was not efficient as a hyperaccumulator plant.

  7. Theoretical study of EPR spectra in Cu2+ - and Mn2+ - doped CaCd(CH3COO)4.6H2O

    International Nuclear Information System (INIS)

    Zhou Yiyang; Zhao Minguang

    1987-08-01

    The EPR spectra of CaCd(CH 3 COO) 4 .6H 2 O doped with Cu 2+ and Mn 2+ have been studied theoretically. A comparison between the calculated results and the experimental data shows quantitatively that the Cu 2+ and Mn 2+ ions substitute for the Cd 2+ and Ca 2+ ions, respectively. This conclusion is consistent with the qualitative assumption given by previous authors. (author). 36 refs, 1 fig., 3 tabs

  8. A study: removal of Cu(II), Cd(II), and Pb(II) ions from real industrial water and contaminated water using activated sludge biomass

    Energy Technology Data Exchange (ETDEWEB)

    Kusvuran, Erdal; Yildirim, Deniz [Arts and Sciences Faculty, Chemistry Department, Cukurova University, Balcali, Adana (Turkey); Samil, Ali [Arts and Sciences Faculty, Chemistry Department, Sutcu Imam University, Kahramanmaras (Turkey); Gulnaz, Osman [Arts and Sciences Faculty, Biology Department, Cukurova University, Balcali, Adana (Turkey)

    2012-11-15

    This study aims to remove of Cu{sup 2+}, Cd{sup 2+}, and Pb{sup 2+} ions from solution and to investigate the adsorption isotherms, adsorption kinetics, and ion-exchange affinities of these metals using waste activated sludge (AS) biomass. The adsorptions of the metals on biomass were optimal at an acidic pH value of 6.0 based on its monolayer capacities. Maximum monolayer capacities of AS biomass (q{sub max}) were calculated as 0.478, 0.358, and 0.280 mmol g{sup -1} for Cu{sup 2+}, Cd{sup 2+}, and Pb{sup 2+}, respectively, and the adsorption equilibrium time was found as 60 min for each metal. The adsorbed amount of metal rose with increasing of initial metal ion concentration. The equilibrium adsorption capacity of AS for initial 0.25 mmol L{sup -1} metal concentration was determined as 0.200, 0.167, and 0.155 mmol g{sup -1} for Cu{sup 2+}, Cd{sup 2+}, and Pb{sup 2+} ions, respectively. These relevant values were determined as 0.420, 0.305, and 0.282 mmol g{sup -1} for Cu{sup 2+}, Cd{sup 2+}, and Pb{sup 2+} ions, respectively, when initial metal concentration was 0.50 mmol L{sup -1}. In the multi-metal sorption system, the adsorption capacity of AS biomass was observed in the order of Cu{sup 2+} > Cd{sup 2+} > Pb{sup 2+}. In the presence of 100 mmol L{sup -1} H{sup +} ion, the order of ion-exchange affinity with H{sup +} was found as Cu{sup 2+} > Cd{sup 2+} > Pb{sup 2+}. The adsorption kinetics were also found to be well described by the pseudo-second-order and intraparticle diffusion models. Two different rate constants were obtained as k{sub i1} and k{sub i2} and k{sub i1} (first stage) was found to be higher than k{sub i2} (second stage). (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. The CdS/Cu2S solar cell. 2

    International Nuclear Information System (INIS)

    Boeer, K.W.

    1981-01-01

    The present state of the art in theory and experimental knowledge of the operation of CdS/Cu 2 S solar cells is reviewed. The subject is covered under the following headings: (1) voltage drop across the cell, (2) Boltzmann solution near the open circuit voltage, (3) boundary condition at the junction-emitter interface, (4) current-voltage characteristics, (5) multiple donors (traps) in the junction, (6) space charge and field limitation caused by field quenching, (7) tunneling under reverse bias, (8) current-dependent interface electron density and interface recombination, (9) kinetics of the characteristics, (10) relevant experimental results, (11) deduction of junction parameters from j-U characteristics, and (12) junction-emitter interface. 37 references are included

  10. On the oxidation behaviour of a Cu-10 vol% Cr in situ composite

    International Nuclear Information System (INIS)

    Haugsrud, R.; Lee, K.L.

    2005-01-01

    The oxidation behaviour of copper and Cu-10 vol% Cr in situ composite was studied at 400-700 deg. C in air and in argon containing 10 ppm O 2 . Oxidation kinetics was investigated by means of isothermal thermogravimetry and the oxide scales were characterized by scanning electron microscopy (SEM). The presence of the chromium fibres increases the oxidation resistance compared to unalloyed copper up to 600 deg. C. The oxidation mechanism and the influence of the different oxidation phenomena on the creep characteristics of the alloy composite are discussed

  11. Bioaccumulation of As, Cd, Cr, Hg(II), and MeHg in killifish (Fundulus heteroclitus) from amphipod and worm prey

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, Jessica, E-mail: dutton.jess@gmail.com; Fisher, Nicholas S., E-mail: nfisher@notes.cc.sunysb.edu

    2011-08-15

    Elevated metal levels in fish are a concern for the fish themselves, their predators, and possibly humans who consume contaminated seafood. Metal bioaccumulation models often rely on assimilation efficiencies (AEs) of ingested metals and loss rate constants after dietary exposure (k{sub ef}s). These models can be used to better understand processes regulating metal accumulation and can be used to make site-specific predictions of metal concentrations in animal tissues. Fish often consume a varied diet, and prey choice can influence these two parameters. We investigated the trophic transfer of As, Cd, Cr, Hg(II), and methylmercury (MeHg) from a benthic amphipod (Leptocheirus plumulosus) and an oligochaete (Lumbriculus variegatus) to killifish (Fundulus heteroclitus) using gamma-emitting radioisotopes. Except for MeHg, AEs varied between prey type. AEs were highest for MeHg (92%) and lowest for Cd (2.9-4.5%) and Cr (0.2-4%). Hg(II) showed the largest AE difference between prey type (14% amphipods, 24% worms). For Cd and Hg(II) k{sub ef}s were higher after consuming amphipods than consuming worms. Tissue distribution data shows that Cd and Hg(II) were mainly associated with the intestine, whereas As and MeHg were transported throughout the body. Calculated trophic transfer factors (TTFs) suggest that MeHg is likely to biomagnify at this trophic step at all ingestion rates, whereas As, Cd, Cr, and Hg(II) will not. Data collected in this study and others indicate that using one prey item to calculate AE and k{sub ef} could lead to an over- or underestimation of these parameters. - Highlights: {yields} We investigated the trophic transfer of metals to killifish from amphipod and worm prey. {yields} Prey choice influences metal accumulation from the diet. {yields} Only MeHg is likely to biomagnify at this trophic step.

  12. Adsorption of Cd(II) and Cu(II) from aqueous solution by carbonate hydroxylapatite derived from eggshell waste

    International Nuclear Information System (INIS)

    Zheng Wei; Li Xiaoming; Yang Qi; Zeng Guangming; Shen Xiangxin; Zhang Ying; Liu Jingjin

    2007-01-01

    Carbonate hydroxylapatite (CHAP) synthesized by using eggshell waste as raw material has been investigated as metal adsorption for Cd(II) and Cu(II) from aqueous solutions. The effect of various parameters on adsorption process such as contact time, solution pH, amount of CHAP and initial concentration of metal ions was studied at room temperature to optimize the conditions for maximum adsorption. The results showed that the removal efficiency of Cd(II) and Cu(II) by CHAP could reach 94 and 93.17%, respectively, when the initial Cd(II) concentration 80 mg/L and Cu(II) 60 mg/L and the liquid/solid ratio was 2.5 g/L. The equilibrium sorption data for single metal systems at room temperature could be described by the Langmuir and Freundlich isotherm models. The highest value of Langmuir maximum uptake, (b), was found for cadmium (111.1 mg/g) and copper (142.86 mg/g). Similar Freundlich empirical constants, K, were obtained for cadmium (2.224) and copper (7.925). Ion exchange and surface adsorption might be involved in the adsorption process of cadmium and copper. Desorption experiments showed that CaCl 2 , NaCl, acetic acid and ultrasonic were not efficient enough to desorb substantial amount of metal ions from the CHAP. The results obtained show that CHAP has a high affinity to cadmium and copper

  13. Alloying effect on hardening of martensite stainless steels of the Fe-Cr-Ni and Fe-Cr-Co systems

    International Nuclear Information System (INIS)

    Fel'dgandler, Eh.G.; Savkina, L.Ya.

    1975-01-01

    The effect of alloying elements is considered on the γ → a-transformation and hardening of certain compositions of the ternary Fe-Cr-Ni- and Fe-Cr-Co alloy systems with the martensite structure. In martensite Fe-(10 to 14)% Cr base steels the elements Co, Cu, W, Ni, Mo, Si, Cr decrease, Mn, Si, Mo, Cu increase, and Cr, Ni, Co decrease the temperature of α → γ-transition. The tempering of martensite steels of the Fe-Cr-Ni- and Fe-Cr-Co-systems containing 10 to 14% Cr, 4 to 9% Ni, and 7 to 12% Co does not lead to hardening. Alloyage of the martensite Fe-Cr-Ni-, Fe-Cr-Co- and Fe-Cr-Ni-Co base separately with Mo, W, Si or Cu leads to a hardening during tempering, the hardening being the higher, the higher is the content of Ni and, especially, of Co. The increase in the content of Mo or Si produces the same effect as the increase in the Co content. In on Fe-Cr-Co or Fe-Cr-Ni-Co based steels alloyed with Mo or Si, two temperature ranges of ageing have been revealed which, evidently, have different hardening natures. The compositions studied could serve as the base material for producing maraging stainless steels having a complex variety of properties

  14. Cd(II), Cu(II)

    African Journals Online (AJOL)

    user

    Depending on the way goethite was pretreated with oxalic acid, affinity for Cd(II) varied ...... Effects and mechanisms of oxalate on Cd(II) adsorption on goethite at different ... precipitation, surfactant mediation, hydrothermal and micro-emulsion.

  15. Comparison of GRCop-84 to Other High Thermal Conductive Cu Alloys

    Science.gov (United States)

    deGroh, Henry C., III; Ellis, David L.; Loewenthal, William S.

    2007-01-01

    The mechanical properties of five copper alloys (GRCop-84, AMZIRC, GlidCop Al-15, Cu-1Cr-0.1Zr, Cu-0.9Cr) competing in high temperature, high heat flux applications such as rocket nozzles, were compared. Tensile, creep, thermal expansion, and compression tests are presented. Tests were done on as-received material, and on material which received a simulated brazing heat treatment at 935 C. The 935 C heat treatment weakened AMZIRC, Cu-1Cr-0.1Zr, and Cu-0.9Cr, and the strength of as-received AMZIRC dropped precipitously as test temperatures exceeded 500 C. The properties of GlidCop Al-15 and GRCop-84 were not significantly affected by the 935 C heat treatment. Thus GRCop-84 is better than AMZIRC, Cu-1Cr-0.1Zr, and Cu-0.9Cr at temperatures greater than 500 C. Ductility was lowest in GlidCop Al-15 and Cu-0.9Cr. The creep properties of GRCop-84 were superior to those of brazed AMZIRC, Cu-1Cr-0.1Zr, and Cu-0.9Cr. At equivalent rupture life and stress, GRCop-84 had a 150 C temperature advantage over brazed AMZIRC; for equivalent rupture life and temperature GRCop-84 was two times stronger. The advantages of GRCop-84 over GlidCop Al-15 associated with ease of processing were confirmed by GlidCop s marginal ductility. In the post brazed condition, GRCop-84 was found to be superior to the other alloys due to its greater strength and creep resistance (compared to AMZIRC, Cu-1Cr-0.1Zr, and Cu-0.9Cr) and ductility (compared to GlidCop Al-15)

  16. Macromolecule oxidation and DNA repair in mussel (Mytilus edulis L.) gill following exposure to Cd and Cr(VI)

    International Nuclear Information System (INIS)

    Emmanouil, C.; Sheehan, T.M.T.; Chipman, J.K.

    2007-01-01

    The oxidation of DNA and lipid was analysed in the marine mussel (Mytilus edulis) in response to exposure (10 μg/l and 200 μg/l) to cadmium (Cd) and chromium [Cr(VI)]. Concentration dependent uptake of both metals into mussel tissues was established and levels of gill ATP were not depleted at these exposure levels. DNA strand breakage in gill cells (analysed by the comet assay) was elevated by both metals, however, DNA oxidation [measured by DNA strand breakage induced by the DNA repair enzyme formamidopyrimidine glycosylase (FPG)] was not elevated. This was despite a statistically significant increase in both malondialdehyde and 4-hydroxynonenal - indicative of lipid peroxidation - following treatment with Cd. In contrast, both frank DNA stand breaks and FPG-induced DNA strand breaks (indicative of DNA oxidation) were increased following injection of mussels with sodium dichromate (10.4 μg Cr(VI)/mussel). The metals also showed differential inhibitory potential towards DNA repair enzyme activity with Cd exhibiting inhibition of DNA cutting activity towards an oligonucleotide containing 8-oxo-7,8-dihydro-2'-deoxyguanosine and Cr(VI) showing inhibition of such activity towards an oligonucleotide containing ethenoadenosine, both at 200 μg/l. The metals thus show DNA damage activity in mussel gill with distinct mechanisms involving both direct and indirect (oxidative) DNA damage, as well as impairing different DNA repair capacities. A combination of these activities can contribute to adverse effects in these organisms

  17. Highly enhanced photocurrent of novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films for photoelectrochemical applications

    International Nuclear Information System (INIS)

    Gohel, Jignasa V.; Jana, A.K.; Singh, Mohit

    2017-01-01

    A novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films synthesized by low-cost process. The properties of ZnO are also enhanced by doping and co-doping. It is also compared with quantum-dot co-sensitization. Optical properties, crystal structure, morphology, and photocurrent are characterized by UV-Vis spectroscopy, XRD, SEM, and solar simulator, respectively. The bandgap is interestingly reduced highly to 2.6 eV for Ag co-doped Cu:ZnO. It is unprecedentedly reduced to 2.1 eV and even 1.97 eV for CdS and PbS-Hg QD-sensitized thin films, respectively. An exceptionally enhanced photocurrent of 17.1 mA/cm"2 is achieved with PbS-Hg-co-sensitized CdS-sensitized Cu:ZnO thin film. This is an excellent achievement, which highly supports the potential of low-cost solar conversion. (orig.)

  18. Highly enhanced photocurrent of novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films for photoelectrochemical applications

    Energy Technology Data Exchange (ETDEWEB)

    Gohel, Jignasa V.; Jana, A.K.; Singh, Mohit [Sardar Vallabhbhai National Institute of Technology, Chemical Engineering Department, Surat, Gujarat (India)

    2017-08-15

    A novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films synthesized by low-cost process. The properties of ZnO are also enhanced by doping and co-doping. It is also compared with quantum-dot co-sensitization. Optical properties, crystal structure, morphology, and photocurrent are characterized by UV-Vis spectroscopy, XRD, SEM, and solar simulator, respectively. The bandgap is interestingly reduced highly to 2.6 eV for Ag co-doped Cu:ZnO. It is unprecedentedly reduced to 2.1 eV and even 1.97 eV for CdS and PbS-Hg QD-sensitized thin films, respectively. An exceptionally enhanced photocurrent of 17.1 mA/cm{sup 2} is achieved with PbS-Hg-co-sensitized CdS-sensitized Cu:ZnO thin film. This is an excellent achievement, which highly supports the potential of low-cost solar conversion. (orig.)

  19. Selected characteristic of silumins with additives of Ni, Cu, Cr, Mo, W and V

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2010-04-01

    Full Text Available The study, presents an investigation results of new grades of silumins containing of: 7,0÷17,0% Si, 4,0% Ni, 4,0% Cu and 0,5% Cr, Mo, W each as well as V. The influence tests were carried out of - antimony addition, strontium and phosphorus modification, supersaturation and ageing processes - on microstructure and silumins hardness. Revealed that investigated silumins, depending on the state, are characte-rized by hardness in the range of 80÷180 HB.

  20. Low-temperature solid-state preparation of ternary CdS/g-C3N4/CuS nanocomposites for enhanced visible-light photocatalytic H2-production activity

    Science.gov (United States)

    Cheng, Feiyue; Yin, Hui; Xiang, Quanjun

    2017-01-01

    Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C3N4/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C3N4/CuS composite exhibits a high visible-light photocatalytic H2-production rate of 57.56 μmol h-1 with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na2S/Na2SO3 mixed aqueous solution as sacrificial agent. The ternary CdS/g-C3N4/CuS composites show the enhanced visible-light photocatalytic H2-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C3N4 in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H2-production activity.

  1. Equilibrium phase of high-entropy FeCoNiCrCu0.5 alloy at elevated temperature

    International Nuclear Information System (INIS)

    Lin, C.-M.; Tsai, H.-L.

    2010-01-01

    The phase transformations of FeCoNiCrCu 0.5 alloy with the as-cast structure and heat-treated structures were studied. The as-cast alloy specimens were first heated at 1050 o C with a holding time of 1 h. Serial heat-treatment processes at 350 o C, 500 o C, 650 o C, 800 o C, 950 o C, 1100 o C, 1250 o C and 1350 o C with a holding time of 24 h were then carried out to understand the phase evolution and the relationship between the microstructure and the hardness of the specimens. The microstructures were investigated and chemical analyses performed by optical microscopy (OM), scanning elector microscopy (SEM), X-ray diffractometer (XRD) and transmission elector microscopy (TEM). The results show that FCC peaks were observed from the X-ray diffraction of the as-cast specimens and a precipitate phase was present in the specimens that had been heated to 950 o C. The hardness of the FeCoNiCrCu 0.5 alloy remained unchanged in the specimens that underwent various heat treatments that were applied in this study.

  2. Percentage of toxic trace elements; Pb, Cr and Cd in certain plastic toys, Isfahan City

    Directory of Open Access Journals (Sweden)

    F Kavehzadeh

    2006-04-01

    Full Text Available Introduction: Recent investigations have detected the presence of significant levels of heavy metals (chromium, lead and cadmium in toys and other PVC products manufactured for children. In some countries, addition of compounds containing toxic metals to toys are limited or prohibited. Methods: To evaluate the safety of some of the plastic toys in the city of Isfahan with respect to toxic trace metals, pb, cr and cd, 75 samples of three types of toys were collected from the toy shop’s and were digested with acid with the two methods ISIRI and ASTM. The heavy metals were determined using atomic absorption spectrophotometer. Variance analysis and T-test were used for data analysis. Results: The result of the study showed that the products tested contained lead, chromium and cadmium and the highest and lowest concentration were related to Pb and Cd, respectively. The statistical analysis of the samples showed that there are no significant differences between ASTM and ISIRI digestion methods. The study revealed that none of the heavy metals in the toy samples exceeded the recommended standard levels. Highest average concentration of Pb and Cd were related to toys with green color and the highest Cr concentration was related to yellow toys in this study. Conclusion: Extensive studies are required to evaluate the quality of the toys being used by children and the toxic trace elements should be eliminated from the plastic materials used for making toys.

  3. Isotermas de sorção de metais pesados em solos do cerrado de Goiás Sorption isotherm of heavy metals in soils of 'Cerrado' of Goiás

    Directory of Open Access Journals (Sweden)

    Luiz F. C. Oliveira

    2010-07-01

    Full Text Available A contaminação do solo e das águas subterrâneas por metais pesados é, extremamente perniciosa por serem basntante persistentes no ambiente. Objetivou-se, com este trabalho, a análise da sorção do Cu, Cr, Zn, Cd, Pb e Ni em Latossolo Vermelho Acriférrico (LVwf, Argissolo Vermelho Eutrófico (PVe, Nitossolo Vermelho Eutroférrico (NVef e Neossolo Quartzarênico (RQ pelos modelos potencial e linear da isoterma Freundlich. Para o estabelecimento de isotermas de sorção adicionaram-se a 5,0 mL de solo e 50,0 mL de solução contendo o metal pesado a ser avaliado com diferentes concentrações, respeitando-se os limites aceitáveis. As isotermas de sorção potencial e linear apresentaram bom ajuste para descrever o comportamento de adsorção dos metais pesados nas diferentes classes de solo estudadas. A sequência da retenção dos metais pesados em ordem decrescente, foi, para: o PVe: Cr+3 > Cr+6 > Ni+2 > Zn+2 > Cu+2 > Pb+2 > Cd+2; o LVwf: Cr+3 > Cr+6 > Ni+2 > Cu+2 > Cd+2 > Zn+2 > Pb+2; o RQ: Cr+6 > Cr+3 >Cu+2 > Pb+2 > Ni+2 > Zn+2 > Cd+2 e, para, o NVef: Cr+3 > Cr+6 > Pb+2 > Cu+2 > Zn+2 > Ni+2 >Cd+2. O RQ foi a classe de solo que apresentou menor retenção de metais em comparação com as demais classes de solo sendo, portanto, mais vulnerável à contaminação de águas subterrâneas.The contamination of soil and groundwater by heavy metals is extremely damaging due to high persistence of heavy metals in the environment. This work targeted the analysis of the sorption in Oxisol Typic Acrustox(LVwf, Ultisol (PVe, Kandic Oxisol (NVef and Quartzipsamment (RQ of heavy metals Cu, Cr, Zn, Cd, Pb and Ni. The sorption of the heavy metals in the soil was evaluated by batch method and described by potential and linear models of the Freundlich isotherm. For the establishment the of sorption isotherm, 50.0 mL of solution containing the heavy metal were added in 5.0 mL of soil, assessing with different concentrations within the acceptable soil

  4. Determination of Cd, Cr, Hg and Pb in plastics from waste electrical and electronic equipment by inductively coupled plasma mass spectrometry with collision-reaction interface technology.

    Science.gov (United States)

    Santos, Mirian C; Nóbrega, Joaquim A; Cadore, Solange

    2011-06-15

    A procedure based on the use of a quadrupole inductively coupled plasma-mass spectrometer equipped with a collision-reaction interface (CRI) for control of spectral overlap interferences was developed for simultaneous determination of Cd, Cr, Hg, and Pb in plastics from waste electrical and electronic equipment (WEEE). The injection of H(2) and He (80 and 60 mL min(-1), respectively) into the sampled plasma, colliding and reacting with potentially interfering polyatomic ions, allows interference-free determination of chromium via its isotopes (52)Cr and (53)Cr that are freed from overlap due to the occurrence of (40)Ar(12)C(+), (40)Ar(12)C(1)H(+), (36)S(16)O(+) or (1)H(36)S(16)O(+). Cadmium, Hg and Pb were directly determined via their isotopes (110)Cd, (111)Cd, (112)Cd, (199)Hg, (200)Hg, (201)Hg, (202)Hg, (206)Pb, (207)Pb, and (208)Pb, without using CRI. The CRI can be quickly activated or deactivated before each analyte measurement. Limits of detection for (52)Cr were 0.04 or 0.14 μg L(-1) with He or H(2) injected in CRI. Cadmium and Pb have LODs between 0.02 and 0.08 μg L(-1) and Hg had 0.93-0.98 μg L(-1), without using CRI. Analyte concentrations for samples varied from 16 to 43, 1 to 11, 4 to 12, and 5 to 13 mg kg(-1) for Cr, Cd, Hg and Pb, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Stabilization of Cd-, Pb-, Cu- and Zn-contaminated calcareous agricultural soil using red mud: a field experiment.

    Science.gov (United States)

    Wang, Yangyang; Li, Fangfang; Song, Jian; Xiao, Ruiyang; Luo, Lin; Yang, Zhihui; Chai, Liyuan

    2018-04-12

    Red mud (RM) was used to remediate heavy metal-contaminated soils. Experiments with two different dosages of RM added to soils were carried out in this study. It was found that soil pH increased 0.3 and 0.5 unit with the dosage of 3 and 5% (wt%), respectively. At the dosage of 5%, the highest stabilization efficiencies for Cd, Pb, Cu and Zn reached 67.95, 64.21, 43.73 and 63.73%, respectively. The addition of RM obviously transferred Cd from the exchangeable fraction to the residual fraction. Meanwhile, in comparison with the control (no RM added), it reduced 24.38, 49.20, 19.42 and 8.89% of Cd, Pb, Cu and Zn in wheat grains at the RM addition dosage of 5%, respectively. At the same time, the yield of wheat grains increased 17.81 and 24.66% at the RM addition dosage of 3 and 5%, respectively. Finally, the addition of RM did not change the soil bacterial community. These results indicate that RM has a great potential in stabilizing heavy metals in calcareous agricultural soils.

  6. Excellent photocatalytic hydrogen production over CdS nanorods via using noble metal-free copper molybdenum sulfide (Cu{sub 2}MoS{sub 4}) nanosheets as co-catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sangyeob; Kumar, D. Praveen; Reddy, D. Amaranatha; Choi, Jiha; Kim, Tae Kyu, E-mail: tkkim@pusan.ac.kr

    2017-02-28

    Highlights: • Developed Cu{sub 2}MoS{sub 4} nanosheets as co-catalysts. • Cu{sub 2}MoS{sub 4} as active replacements for precious noble metal. • Controlled charge recombination for use in photocatalytic H{sub 2} evolution. • Obtained superior rate of H{sub 2} production by using Cu{sub 2}MoS{sub 4} loaded CdS nanorods. - Abstract: Charge carrier recombination and durability issues are major problems in photocatalytic hydrogen (H{sub 2}) evolution processes. Thus, there is a very important necessitate to extend an efficient photocatalyst to control charge-carrier dynamics in the photocatalytic system. We have developed copper molybdenum sulfide (Cu{sub 2}MoS{sub 4}) nanosheets as co-catalysts with CdS nanorods for controlling charge carriers without recombination for use in photocatalytic H{sub 2} evolution under simulated solar light irradiation. Effective control and utilization of charge carriers are possible by loading Cu{sub 2}MoS{sub 4} nanosheets onto the CdS nanorods. The loading compensates for the restrictions of CdS, and stimulated synergistic effects, such as efficient photoexcited charge separation, lead to an improvement in photostability because of the layered structure of the Cu{sub 2}MoS{sub 4}nanosheets. These layered Cu{sub 2}MoS{sub 4} nanosheets have emerged as novel and active replacements for precious noble metal co-catalysts in photocatalytic H{sub 2} production by water splitting. We have obtained superior H{sub 2} production rates by using Cu{sub 2}MoS{sub 4} loaded CdS nanorods. The physicochemical properties of the composites are analyzed by diverse characterization techniques.

  7. Synthesis, crystal structure and electrical properties of the tetrahedral quaternary chalcogenides CuM{sub 2}InTe{sub 4} (M=Zn, Cd)

    Energy Technology Data Exchange (ETDEWEB)

    Nolas, George S., E-mail: gnolas@usf.edu [Department of Physics, University of South Florida, Tampa, FL 33620 (United States); Hassan, M. Shafiq; Dong, Yongkwan [Department of Physics, University of South Florida, Tampa, FL 33620 (United States); Martin, Joshua [Material Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899 (United States)

    2016-10-15

    Quaternary chalcogenides form a large class of materials that continue to be of interest for energy-related applications. Certain compositions have recently been identified as possessing good thermoelectric properties however these materials typically have the kesterite structure type with limited variation in composition. In this study we report on the structural, optical and electrical properties of the quaternary chalcogenides CuZn{sub 2}InTe{sub 4} and CuCd{sub 2}InTe{sub 4} which crystallize in the modified zinc-blende crystal structure, and compare their properties with that of CuZn{sub 2}InSe{sub 4}. These p-type semiconductors have direct band gaps of about 1 eV resulting in relatively high Seebeck coefficient and resistivity values. This work expands on the research into quaternary chalcogenides with new compositions and structure types in order to further the fundamental investigation of multinary chalcogenides for potential thermoelectrics applications. - Graphical abstract: The structural, optical and electrical properties of the quaternary chalcogenides CuZn{sub 2}InTe{sub 4} and CuCd{sub 2}InTe{sub 4} are reported for the first time. The unique crystal structure allows for relatively good electrical transports and therefore potential for thermoelectric applications. - Highlights: • The physical properties of CuZn{sub 2}InTe{sub 4} and CuCd{sub 2}InTe{sub 4} are reported for the first time. • These materials have potential for thermoelectric applications. • Their direct band gaps also suggest potential for photovoltaics applications.

  8. Transformation of natural ferrihydrite aged in situ in As, Cr and Cu contaminated soil studied by reduction kinetics

    DEFF Research Database (Denmark)

    Nielsen, Sanne Skov; Kjeldsen, Peter; Hansen, Hans Christian Bruun

    2014-01-01

    following 4 yr of in situ burial at a contaminated site was examined in samples of impure (Si-bearing) ferrihydrite in soil heavily polluted with As, Cr and Cu. The samples are so-called iron water treatment residues (Fe-WTR) precipitated from anoxic groundwater during aeration. The extent of transformation...

  9. Expresión fenotípica de las moléculas CD5 y CD6 en la leucemia linfoide crónica B-CD5+ The B-CD5+ chronic lymphoid leukemia related to the phenotype expression

    Directory of Open Access Journals (Sweden)

    Bertha Beatriz Socarrás Ferrer

    2009-04-01

    Full Text Available Las moléculas CD5 y CD6 tienen función coestimuladora y muestran homología en su estructura. Se evaluó la expresión de la molécula CD6 mediante el uso del anticuerpo monoclonal anti-CD6 (T1 en el inmunofenotipaje celular de pacientes con leucemia linfoide crónica By se comparó con la expresión de la molécula CD5.Los resultados demuestranuna homología en la expresión fenotípica de ambas moléculas, CD5 y CD6, lo que asociado con que ambos receptores linfocitarios se encuentran físicamente vinculados, permite sugerir que la molécula CD6 constituye un marcador biológico de interés en la evaluación del pronóstico y la posibilidad de nuevas variantes terapéuticas en esta enfermedad.CD5 and CD6 molecules have a co-stimulant function and show homology in structure. We assessed CD6 molecule expression using anti-CD6 (T1 monoclonal antibody in the cellular immunophenotyping from patients presenting B chronic lymphoid leukemia, and it was compared to CD5 molecule expression. Results show a homology in phenotype expression of both molecules (CD5 and CD6, what associated with the fact that both lymphocyte receptors are physically linked, allow to suggest that CD6 molecule is a interesting biological marker in prognosis assessment, and the possibility of new therapeutic variants in this disease.

  10. Solar excitation of CdS/Cu2S photovoltaic cells

    Science.gov (United States)

    Boer, K. W.

    1976-01-01

    Solar radiation of five typical clear weather days and under a variety of conditions is used to determine the spectral distribution of the photonflux at different planes of a CdS/Cu2S solar cell. The fractions of reflected and absorbed flux are determined at each of the relevant interfaces and active volume elements of the solar cell. The density of absorbed photons is given in respect to spectral and spatial distribution. The variance of the obtained distribution, with changes in insolation and absorption spectra of the active solar cell layers, is indicated. A catalog of typical examples is given in the appendix.

  11. Structural and photocarrier radiometric characterization of Cu{sub x}(CdTe){sub y}O{sub z} thin films growth by reactive sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez-Hernandez, R., E-mail: ruvel2@yahoo.com.m [Division de Investigacion y Posgrado, Facultad de Ingenieria, Universidad Autonoma de Queretaro, Cerro de las Campanas S/N, Queretaro, Qro., Mexico, C.P. 76010 (Mexico); Rojas-Rodriguez, I. [Universidad Tecnologica de Queretaro, Av. Pie de la Cuesta S/N, Sn. Pedrito Penuelas, Queretaro, Qro. Mexico (Mexico); Carmona-Rodriguez, J.; Jimenez-Sandoval, S. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Apartado Postal 1-798, Queretaro, Qro., Mexico C.P.76001 (Mexico); Rodriguez-Garcia, M.E. [Departamento de Nanotecnologia, Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Campus Juriqulla, Apartado Postal 1-1010, Queretaro, Qro. Mexico (Mexico)

    2011-01-31

    This research presents a structural and photocarrier radiometric (PCR) characterization of Cu{sub x}(CdTe){sub y}O{sub z} thin films grown using reactive radiofrequency co-sputtering. Electronic distribution induced by variations in dopant concentration as a function of the position was studied using photocarrier radiometric images. Optical and structural characterization of these thin films was carried out by using micro Raman spectroscopy and X-ray diffraction. Due to its nondestructive and noncontact characteristics, the PCR is an excellent technique that permits one to obtain details of lateral electronic distribution across the sample. It was found that Cu target power influences the electronic distribution and produces different phases such as Cu{sub 2}Te and CdO.

  12. Adsorption of heavy metals by bio-chars produced from pyrolysis of paper mulberry from simulated industrial wastewater

    International Nuclear Information System (INIS)

    Adil, S.; Asma, M.

    2014-01-01

    Paper mulberry bio-char (by-product of pyrolysis) was evaluated for the removal of heavy metals (Cd, Cr, Cu, Zn and Pb) from simulated industrial waste water. The surface properties and surface area of the bio-char was found suitable for metal adsorption. Batch sorption studies for adsorption potential of paper mulberry bio-char for Cd, Cr, Cu, Pb and Zn were investigated under different experimental conditions of pH, temperature and contact time. Maximum removal efficiency of Cd, Cu, Pb and Zn was 97.8, 76.8, 85.6, and 82.2 % respectively at pH 12 while maximum removal of Cr was recorded (98%) at pH 2. The removal efficiency showed different behaviour at different contact times. Maximum removal efficiency of Cd, Cr, Zn was 81, 86, 61.4% at contact time of 3 hr. The maximum removal of Cu was 64.2% observed at a contact time of 4 hours while the maximum removal of Pb and Zn was 85% at contact time of 2 hr. The values of the thermodynamic parameters, enthalpy delta H, Gibbs free energy delta G of sorption and entropy delta So were calculated to define endothermic or exothermic behavior of the sorbent used. Negative value of delta G for Cd, Cu, Cr and Pb indicated paper mulberry bio-char as a feasible sorbent for the efficient removal of Cd, Cu, Cr and Pb. Negative value of delta H was observed for Cd and Pb indicating that the adsorption process is exothermic while positive value of delta H was calculated for Cu, Cr and Zn showed that the adsorption is endothermic. The results obtained showed that plant residue bio-char can act as an effective sorbent for the removal of heavy metals from aqueous solutions. (author)

  13. Tamarix hispida metallothionein-like ThMT3, a reactive oxygen species scavenger, increases tolerance against Cd(2+), Zn(2+), Cu(2+), and NaCl in transgenic yeast.

    Science.gov (United States)

    Yang, Jingli; Wang, Yucheng; Liu, Guifeng; Yang, Chuanping; Li, Chenghao

    2011-03-01

    A metallothionein-like gene, ThMT3, encoding a type 3 metallothionein, was isolated from a Tamarix hispida leaf cDNA library. Expression analysis revealed that mRNA of ThMT3 was upregulated by high salinity as well as by heavy metal ions, and that ThMT3 was predominantly expressed in the leaf. Transgenic yeast (Saccharomyces cerevisiae) expressing ThMT3 showed increased tolerance to Cd(2+), Zn(2+), Cu(2+), and NaCl stress. Transgenic yeast also accumulated more Cd(2+), Zn(2+), and NaCl, but not Cu(2+). Analysis of the expression of four genes (GLR1, GTT2, GSH1, and YCF1) that aid in transporting heavy metal (Cd(2+)) from the cytoplasm to the vacuole demonstrated that none of these genes were induced under Cd(2+), Zn(2+), Cu(2+), and NaCl stress in ThMT3-transgenic yeast. H(2)O(2) levels in transgenic yeast under such stress conditions were less than half those in control yeast under the same conditions. Three antioxidant genes (SOD1, CAT1, and GPX1) were specifically expressed under Cd(2+), Zn(2+), Cu(2+), and NaCl stress in the transgenic yeast. Cd(2+), Zn(2+), and Cu(2+) increased the expression levels of SOD1, CAT1, and GPX1, respectively, whereas NaCl induced the expression of SOD1 and GPX1.

  14. Determination of field-based sorption isotherms for Cd, Cu, Pb and Zn in Dutch soils

    NARCIS (Netherlands)

    Otte JG; Grinsven JJM van; Peijnenburg WJGM; Tiktak A; LBG; ECO

    1999-01-01

    Sorption isotherms for metals in soil obtained in the laboratory generally underpredict the observed metal content in the solid phase in the field. Isotherms based on in-situ data are therefore required. The aim of this study is to obtain field-based sorption isotherms for Cd, Cu, Pb and Zn as input

  15. Retention and distribution of Cu, Pb, Cr, and Zn in a full-scale hybrid constructed wetland receiving municipal sewage

    NARCIS (Netherlands)

    Xiao, H.W.; Zhang, S.L.; Zhai, J.; He, Q.; Mels, A.R.; Ning, K.J.; Liu, J.

    2013-01-01

    This study was conducted to investigate the retention and distribution of Cu, Pb, Cr, and Zn in a hybrid constructed wetland (CW) that consists of both vertical baffled flow wetlands (VBFWs) and horizontal subsurface flow wetlands (HSSFs) with unique flow regimes and oxygen distribution. The heavy

  16. DETERMINATION OF LIMIT DETECTION OF THE ELEMENTS N, P, K, Si, Al, Fe, Cu, Cd, WITH FAST NEUTRON ACTIVATION USING NEUTRON GENERATOR

    OpenAIRE

    Sunardi, Sunardi; Muryono, Muryono

    2010-01-01

    Determination of limit detection of the elements N, P, K, Si, Al, Fe, Cu, Cd, with fast neutron activation using neutron generator has been done.  Samples prepared from SRM 2704, N, P, K elements from MERCK, Cu, Cd, Al from activation foil made in San Carlos, weighted and packed for certain weight then iradiated during 30 minutes with 14 MeV fast neutron using the neutron generator and then counted with gamma spectrometry (accuspec).  At this research condition of neutron generator was set at...

  17. Population health risk via dietary exposure to trace elements (Cu, Zn, Pb, Cd, Hg, and As) in Qiqihar, Northeastern China.

    Science.gov (United States)

    Luo, Jinming; Meng, Jia; Ye, Yajie; Wang, Yongjie; Bai, Lin

    2018-02-01

    The estimated daily intakes (EDIs) of six trace elements (Cu, Zn, Pb, Cd, Hg, and As) in vegetables (leafy vegetable, i.e., bok choy, fruit vegetables, i.e., cucumber and tomato, and other categories, i.e., mushroom, kidney bean, and potato), cereals (rice and wheat flour), and meats (pork, mutton, and beef) most commonly consumed by adult inhabitants of Qiqihar, Northeastern China, were determined to assess the health status of local people. The average EDIs of Cu, Zn, Pb, Cd, Hg, and As were with 20.77 μg (kg bw) -1 day -1 of Cu, 288 μg (kg bw) -1 day -1 of Zn, 2.01 μg (kg bw) -1 day -1 of Pb, 0.41 μg (kg bw) -1 day -1 of Cd, 0.01 μg (kg bw) -1 day -1 of Hg, and 0.52 μg (kg bw) -1 day -1 of As, respectively, which are below the daily allowance recommended by FAO/WHO. However, the maximum EDIs of Pb and Cd were 4.56 μg (kg bw) -1 day -1 and 1.68 μg (kg bw) -1 day -1 , respectively, which are above the recommended levels [i.e., 3.58 μg (kg bw) -1 day -1 for Pb and 1.0 μg (kg bw) -1 day -1 for Cd] by FAO/WHO. This finding indicates that the potential health risk induced by daily ingestion of Pb and Cd for the local residents should receive a significant concern. Similarly, we detected elevated Pb and Cd concentrations, i.e., with average of 13.58 and 0.60 mg kg -1 dw, respectively, in the adult scalp hairs. Consumption of rice, potato, bok choy, and wheat flour contributed to 75 and 82% of Pb and Cd daily intake from foodstuffs. Nevertheless, human scalp hair is inappropriate biological material for determination of the nutritional status of trace elements in this region.

  18. 210Pb geochronology and trace metal fluxes (Cd, Cu and Pb) in the Gulf of Tehuantepec, South Pacific of Mexico

    International Nuclear Information System (INIS)

    Ruiz-Fernandez, Ana Carolina; Paez-Osuna, Federico; Machain-Castillo, Maria Luisa; Arellano-Torres, Elsa

    2004-01-01

    Distributions of Al, Cd, Cu, Fe, Li, Mn and Pb were analyzed in a sediment core collected in the Gulf of Tehuantepec, an important fisheries region located in the South Pacific of Mexico, where data on metal accumulation and accretion rates were previously almost nonexistent. Depth profiles of metal concentrations were converted to time-based profiles by using a 210 Pb-derived vertical accretion rate, estimated to be 0.05 cm year -1 on the average. Sediments were dated up to 8 cm depth, corresponding to a layer of ca. 140 years old. The historical changes of metal accumulation along the sediment core have shown a moderate enrichment of Cd, Cu and Pb concentrations at present, of about threefold the corresponding background concentrations. Chronological trace metal records showed that metal fluxes have increased over the last 20 years, reaching the maximum values at present of 2.5, 22.5 and 45.8 (μg cm -2 year -1 ) for Cd, Pb and Cu, respectively. These increments in metal fluxes are likely influenced by the development of anthropogenic land-based activities since over this period of time oil production activities in the region have had a significant development

  19. Effect of cobalt on microstructure and properties of AlCr1.5CuFeNi2Cox high-entropy alloys

    Science.gov (United States)

    Kukshal, Vikas; Patnaik, Amar; Bhat, I. K.

    2018-04-01

    The present paper investigates the effect of Co addition on the alloying behaviour, microstructure and the resulting properties of cast AlCr1.5CuFeNi2Cox high-entropy alloys intended to be used for high temperature applications. The elements Al, Cr, Cu, Fe, Ni and Co (Purity > 99) weighing approximately 800 g was melted in a high temperature vacuum induction furnace. The microstructure, phase transformation, density, microhardness and compressive strength of the samples were analysed using x-ray diffraction (XRD), scanning electron microscopes (SEM), Vickers microhardness tester and universal Testing machine. The crystalline structure of the alloys exhibits simple FCC and BCC phases. The microstructures investigation of the alloys shows the segregation of copper in the interdendritic region resulting in Cu-rich FCC phase. The addition of Co further enhances the formation of FCC phase resulting in the decrease in micro hardness value of the alloys, which varies from 471 HV to 364 HV with increase in the cobalt content from x = 0 to x = 1 (molar ratio). The similar decreasing trend is also observed for the compressive strength of the alloys.

  20. Electrochemical preparation of vertically aligned, hollow CdSe nanotubes and their p-n junction hybrids with electrodeposited Cu2O.

    Science.gov (United States)

    Debgupta, Joyashish; Devarapalli, Ramireddy; Rahman, Shakeelur; Shelke, Manjusha V; Pillai, Vijayamohanan K

    2014-08-07

    Vertically aligned, hollow nanotubes of CdSe are grown on fluorine doped tin oxide (FTO) coated glass substrates by ZnO nanowire template-assisted electrodeposition technique, followed by selective removal of the ZnO core using NH4OH. A detailed mechanism of nucleation and anisotropic growth kinetics of nanotubes have been studied by a combination of characterization tools such as chronoamperometry, SEM and TEM. Interestingly, "as grown" CdSe nanotubes (CdSe NTs) on FTO coated glass plates behave as n-type semiconductors exhibiting an excellent photo-response (with a generated photocurrent density value of ∼ 470 μA cm(-2)) while in contact with p-type Cu2O (p-type semiconductor, grown separately on FTO plates) because of the formation of a n-p heterojunction (type II). The observed photoresponse is 3 times higher than that of a similar device prepared with electrodeposited CdSe films (not nanotubes) and Cu2O on FTO. This has been attributed to the hollow 1-D nature of CdSe NTs, which provides enhanced inner and outer surface areas for better absorption of light and also assists faster transport of photogenerated charge carriers.

  1. Thermal, magnetic, and structural properties of soft magnetic FeCrNbCuSiB alloy ribbons

    International Nuclear Information System (INIS)

    Rosales-Rivera, A.; Valencia, V.H.; Quintero, D.L.; Pineda-Gomez, P.; Gomez, M.

    2006-01-01

    The thermal, magnetic and structural properties of amorphous magnetic Fe 73.5-x Cr x Nb 3 Cu 1 Si 13.5 B 9 alloy ribbons, with x=0, 2, 4, 6, 8, and 10, were studied by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), magneto-impedance measurements and X-ray diffraction (XRD). The ribbons exhibit ultrasoft magnetic behavior, especially giant magneto-impedance effect, GMI. A three-peak behavior was observed in GMI curves. Particular attention has been given to observation of crystallization kinetics via DSC and TGA. The primary crystallization T pcr , and Curie T c , temperatures were determined from DSC and TGA data, respectively. The effect of partial substitution of iron by Cr on the thermal and magnetic properties is discussed

  2. Effect of CuPc layer insertion on the memory performance of CdS nanocomposite diodes

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, S.K., E-mail: surya@pu.ac.in; Kaur, Ramneek; Jyoti

    2016-09-15

    Highlights: • CdS nanocomposite as an active layer investigated for memory device application. • Effect of copper phthalocyanine layer insertion on the memory performance studied. • Bipolar switching behaviour with high ON/OFF ratio ∼1.4 × 10{sup 4}. • Series resistance and interface states dominate the electrical properties of the device. - Abstract: In the present work, semiconductor diodes with CdS nanocomposite as an active layer have been fabricated and investigated for memory device applications. The effect of copper phthalocyanine (CuPc) layer insertion between the bottom electrode and CdS nanocomposite has been studied. I–V characteristics show electrical hysteresis behaviour vital for memory storage application. The as-fabricated devices exhibit bipolar switching behaviour with OFF to ON state transition at positive bias and vice versa. Device with CuPc layer exhibits I{sub ON}/I{sub OFF} ratio ∼ 1.4 × 10{sup 4}. Possible conduction mechanism has been described on the basis of theoretical current conduction models. The frequency dispersion capacitance, series resistance and conductance of the devices have been studied and discussed. At low frequency, the series resistance and the interface states dominate the electrical properties of the device. The results indicate that the multilayered devices open up the possibility of new generation non-volatile memory devices with low cost, high density and stability.

  3. Fabrication of dye sensitized solar cell using Cr doped Cu-Zn-Se type chalcopyrite thin film

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, D. Paul; Venkateswaran, C. [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai-600 025 (India); Ganesan, S.; Suthanthiraraj, S. Austin; Maruthamuthu, P. [Department of Energy, University of Madras, Guindy Campus, Chennai 600 025 (India); Kovendhan, M. [Department of Physics, Presidency College, Chennai 600 005 (India)

    2011-09-15

    Chalcopyrites are a versatile class of semiconductors known for their potential in photovoltaic applications. Considering the well established CuInSe{sub 2} as a prototype system, a new compound of the chalcopyrite type, Cu{sub 1-x}Zn{sub 1-y}Se{sub 2-{delta}}, by replacing In with Zn, has been prepared (both undoped and 2% Cr doped) by the metallurgical method. Thin films have been deposited by the thermal evaporation technique using the stabilized polycrystalline compounds as charge. Structural, compositional, morphological, and optical properties of the films are analyzed and reported. Use of these films as electrodes in dye sensitized solar cell (DSSC) is demonstrated. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Study on accumulation of Fe, Pb, Zn, Ni and Cd in Nerita lineata and Thais bitubercularis from Tanjung Harapan and Teluk Kemang, Malaysia.

    Directory of Open Access Journals (Sweden)

    Tengku

    2017-01-01

    Full Text Available The presence of Cd, Cu, Zn, Ni, Fe, Al, Zn, Mn, Cr, and Sn were attributed to metal industries. Cu contamination was associated with piggery industry. Shipping activities contribute to elevated levels of Pb, Cu and As. Elevated levels of metals in the sediments are attributed to anthropogenic activities. Samples were collected in April 2012 and analysed using inductively coupled plasma mass spectrometry (ICP-MS. Fe is the most abundant metal in the tissue and shell compared to the rest of the metals. The concentrations of heavy metals in the soft tissues of Nerita lineata taken from Tanjung Harapan follow this order: Fe > Zn > Ni > Cu > Cd while in Thais bitubercularis, the metal concentrations were higher following the order of Fe > Zn > Cu > Ni > Cd. The samples taken from Teluk Kemang were higher and exhibited different trend for both organisms. Results from this study are useful for further exploration of Thais bitubercularis as accumulators of Cu, Cd, and Zn. For recommendation, more studies on monitoring the concentration level of heavy metals in marine environment should be done regularly and increase numbers of samples use to biomonitor the heavy metals in marine environment as it is important to have information or data regarding the quality of marine environment in order to control pollution such as water pollution from being contaminated with heavy metals. This is essential as the pollutants emit in the marine environment may affect marine lives as well as human’s health

  5. Study on procedure for determination of Cr, As, Se, Cd, Hg, Pb in some kinds of herb products such as: kind of fungus, philamin... by ICP-MS

    International Nuclear Information System (INIS)

    Pham Ngoc Khai; Do Van Thuan; Nguyen Thi Kim Dung; Nguyen Hong Minh

    2007-01-01

    The determination of Cr, As, Se, Cd, Hg, Pb in herb products such as: kind of fungus, philamin, etc by ICP-MS has been studied. The effects of the parameters of ICP-MS instrument, concentration of nitric acid and high concentration of some elements on the determination of Cr, As, Se, Cd, Hg, Pb by ICP-MS has been concerned. The study and choice the suitable internal standard for the accurate determination of Hg has been sold. The suitable parameters of the microwave, composition and content of the acid mixture for the complete decomposition of the sample have been studied. The recommended procedure has been applied to the determination of Cr, As, Se, Cd, Hg, Pb in the standard samples and real samples. The error of the results is acceptable. (author)

  6. Studies on coordination chemistry and bioactivity of complexes of a bidentate oxygen-oxygen donor ligand, 1,2-dibenzoylhydrazine, with Cr3+, Co2+, Ni2+, Cu2+ and Zn2+ Ions

    International Nuclear Information System (INIS)

    Tarafder, M.T.H.; Lai Wee Wong; Crouse, Karen A.; Ali, A.M.; Yamin, B.M.; Fun, H.-K.

    2003-08-01

    A new bidentate ligand, 1,2-dibenzoylhydrazine (DBHz), with OO donor sequences, was prepared. Several complexes of DBHz containing Cr(JJI), Fe(UI), Co(U), Ni(JJ), Cu(II) and Zn(TJ) ions have been synthesized and characterized by CHN analyses, IR, molar conductivity and UV/Visible spectroscopic studies. All of the compounds were tested for their antibacterial, antifungal and anticancer properties. DBHz was very effective against Pseudomonas aeruginosa, Bacillus subtilis mutant and Bacillus subtilis wild type bacteria. It was also effective against Saccaromyces cereiviceae, Candida albicans, Candida albicans lypolytica and Aspergillus ochraceous fungi. The free ligand, DBHz, in particular, was strongly active against colon cancer cell lines (HT-29), with a CD 50 value of 2.5 /μg/ml. (author)

  7. Evaluation of the effects of the metals Cd, Cr, Pb and their mixture on the filtration and oxygen consumption rates in catarina scallop, Argopecten ventricosus juveniles.

    Science.gov (United States)

    Sobrino-Figueroa, Alma S; Cáceres-Martinez, Carlos

    2014-01-01

    In this work, we evaluated the effect of sublethal concentrations ( LC25, LC10 and LC5) of cadmium, chromium, lead, and their mixture on the filtration rate and oxygen consumption rate of Catarina scallop, Argopecten ventricosus (Sowerby, 1842), juveniles, in order to evaluate the use of these biomarkers as a reliable tool in environmental monitoring studies, because these metals have been found at high levels in water and sediments in the Mexican Pacific systems. An inverse dose-response relationship was observed when metal concentration and exposure time increased, the filtration rate and oxygen consumption rate reduced. The physiological responses evaluated in this study were sufficiently sensitive to detect alterations in the organisms at 0.014 mg l(-1) Cd, 0.311 mg l(-1) Cr, 0.125 mg l(-1) Pb and 0.05 mg l(-1) Cd + Cr + Pb at 24 and 72 hrs. Cd showed the most drastic effect. The Catarina scallop juveniles were more sensitive to Cd, Cr and Pb as compared to other bivalves. The biomarkers evaluated are a reliable tool to carry out environmental monitoring studies.

  8. Aminoacid N-substituted 1,4,7-triazacyclononane and 1,4,7,10-tetraazacyclododecane Zn2+, Cd2+ and Cu2+ complexes. A preparative, potentiometric titration and NMR spectroscopic study.

    Science.gov (United States)

    Plush, Sally E; Lincoln, Stephen F; Wainwright, Kevin P

    2004-05-07

    The pK(a)s and Zn2+, Cd2+ and Cu2+ complexation constants (K) for 1,4,7-tris[(2''S)-acetamido-2''-(methyl-3''-phenylpropionate)]-1,4,7-triazacyclononane, 1, 1,4,7-tris[(2''S)-acetamido-2''-(1''-carboxy-3''-phenylpropane)]-1,4,7-triazacyclononane, H(3)2, 1,4,7-tris[(2''S)-acetamido-2''-(methyl-3''-(1H-3-indolyl)propionate)]-1,4,7-triazacyclononane, 3, and 1,4,7,10-tetrakis[(2''S)-acetamido-2''-(methyl-3''-phenylpropionate)]-1,4,7,10-tetraazacyclododecane, 4, 1,4,7,10-tetrakis[(2''S)-acetamido-2''-(1''-carboxy-3''-phenylpropane)]-1,4,7,10-tetraazacyclododecane, H(4)5, in 20 : 80 v/v water-methanol solution are reported. The pK(a)s within the potentiometric detection range for H(3)1(3+) = 8.69 and 3.59, for H(6)2(3+) = 9.06, 6.13, 4.93 and 4.52, H(3)3(3+) = 8.79 and 3.67, H(4)4(4+) = 8.50, 5.62 and 3.77 and for H(8)5(4+) = 9.89, 7.06, 5.53, 5.46, 4.44 and 4.26 where each tertiary amine nitrogen is protonated. The complexes of 1: [Zn(1)]2+(9.00), [Cd(1)]2+ (6.49), [Cd(H1)]3+ (4.54) and [Cu(1)]2+ (10.01) are characterized by the log(K/dm3 mol(-1)) values shown in parentheses. Analogous complexes are formed by 3 and 4: [Zn(3)]2+ (10.19), [Cd(3)]2+ (8.54), [Cu(3)]2+ (10.77), [Zn(4)]2+ (11.41) [Cd(4)]2+ (9.16), [Cd(H4)]3+ (6.16) and [Cu(4)]2+ (11.71). The tricarboxylic acid H(3)2 generates a greater variety of complexes as exemplified by: [Zn(2)-] (10.68) [Zn(H2)] (6.60) [Zn(H(2)2)+] (5.15), [Cd(2)](-) (4.99), [Cd(H2)] (4.64), [Cd(H2(2))]+ (3.99), [Cd(H(3)2)]2+ (3.55), [Cu(2)](-) (12.55) [Cu(H2)] (7.66), [Cu(H(2)2)]+ (5.54) and [Cu(2)2](4-) (3.23). The complexes of H(4)5 were insufficiently soluble to study in this way. The 1H and 13C NMR spectra of the ligands are consistent with formation of a predominant Zn2+ and Cd2+ Delta or Lambda diastereomer. The preparations of the new pendant arm macrocycles H(3)2, 3, 4 and H(4)5 are reported.

  9. Health risk assessment of heavy metals contamination in tomato and green pepper plants grown in soils amended with phosphogypsum waste materials.

    Science.gov (United States)

    Al-Hwaiti, Mohammad; Al-Khashman, Omar

    2015-04-01

    Phosphogypsum (PG) is a waste produced by the phosphate fertilizer industry that has relatively high concentrations of some heavy metals (e.g., Cd, Cr, Cu, Pb, V, and Zn). The present study was conducted to investigate heavy metal contamination in soils and vegetables (tomatoes and green peppers) and to evaluate the possible health risks associated with the consumption of vegetables grown in PG-amended soils. The enrichment factor values indicated that Pb, Cr, Cu, Ni, Zn, and V were depleted to minimally enriched, and Cd was moderately enriched. The pollution load index values indicated that the PG-amended soils were strongly polluted with Cd, moderately polluted with Cr and Ni, and slightly polluted with Pb, Cu, Zn and V. The geo-accumulation index values indicated that the PG-amended soils were uncontaminated with Pb, Cr, Cu, Ni, Zn, V, and moderately contaminated with Cd. The trace metal transfer for Cd, Cr, Pb, and Zn concentrations was below what are considered as acceptable limits ( Pb > Cd > Cr. The biological absorption coefficients in plants are, in order of highest to lowest, Pb > Zn > Cd > Cr, which suggests that Pb is more bioavailable to plants than Cd, Cr, and Zn. Furthermore, this study highlights that both adults and children consuming vegetables (e.g., tomatoes and green peppers) grown in PG-amended soils ingest significant amounts of the metals studied. However, the daily intake of metals (DIM) and the health risk index (HRI) values are contaminated soils, which were not included in this study.

  10. Study of the analytic quality in the determinations of Cr, Fe, Mn, Cu, Zn, Pb and Hg through conventional and nuclear analytical techniques in mosses of the MATV; Estudio de la calidad analitica en las determinaciones de Cr, Fe, Mn, Cu, Zn, Pb y Hg a traves de tecnicas analiticas nucleares y convencionales en musgos de la ZMVT

    Energy Technology Data Exchange (ETDEWEB)

    Caballero S, B.

    2013-07-01

    To evaluate the environmental risks of air pollution and to facilitate the decision-making for control, is necessary to have the capacity to generate data with analytical quality. A comparison between nuclear (Neutron activation analysis and total reflection X-ray fluorescence spectrometry) and no nuclear analytical techniques (atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry) for simultaneous determination of metal content (Cr, Cu, Fe, Hg, Mn, Pb and Zn) in mosses from Metropolitan Area of the Toluca Valley (MATV) was performed. Epiphytic mosses (Fabriona ciliaris and Leskea angustata) were sampled in two campaigns, 16 sites (urban, transition and natural) and were prepared for each technique. The biological certified reference materials were used for the quality control and to evaluate accuracy, precision, linearity, detection and quantification limits. Results show that nuclear analytical techniques and no nuclear applied in chemical analysis of Cr, Cu, Fe, Hg, Mn, Pb and Zn in moss from MATV are comparable and therefore all of these can potentially be used for this purpose. However, if its considered both, the performance parameters and economic/operational characteristics is widely recommended inductively coupled plasma optical emission spectrometry, conventional analytical technique, which showed the highest analytical grade quality. Also were observed spatial and temporal variations in the concentrations of Cr, Cu, Fe, Hg, Mn, Pb and Zn in mosses from MATV and was discussed its potential origin. The urban sites had the highest concentration of anthropogenic elements as Cr, Cu, Fe, Hg, Pb and Zn because are strongly impacted by roads with high vehicle traffic. (Author)

  11. A comparative study on Cu, Cr and As removal from CCA-treated wood waste by dialytic and electrodialytic processes

    DEFF Research Database (Denmark)

    Velizarova, Emiliya; Ribeiro, Alexandra B.; Ottosen, Lisbeth M.

    2002-01-01

    In this study, electrodialytic and dialytic techniques were used for Cu, Cr and As removal from 20-years out-of-service CCA-treated Pinus pinaster Ait. pole. The effect of applying direct current, as "cleaning agent", of up to 120mA was investigated. Focus was given to a parallel comparison...

  12. Low-temperature solid-state preparation of ternary CdS/g-C{sub 3}N{sub 4}/CuS nanocomposites for enhanced visible-light photocatalytic H{sub 2}-production activity

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Feiyue; Yin, Hui; Xiang, Quanjun, E-mail: xiangqj@mail.hzau.edu.cn

    2017-01-01

    Highlights: • CdS/g-C{sub 3}N{sub 4}/CuS composite were synthesized by low-temperature solid-state method. • CdS/g-C{sub 3}N{sub 4}/CuS show enhanced visible-light photocatalytic H{sub 2} evolution activity. • The enhanced photocatalytic H{sub 2} production activity is due to the heterojunction. • Heterojunction between the components promote charge separation/transfer property. - Abstract: Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C{sub 3}N{sub 4}/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C{sub 3}N{sub 4}/CuS composite exhibits a high visible-light photocatalytic H{sub 2}-production rate of 57.56 μmol h{sup −1} with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na{sub 2}S/Na{sub 2}SO{sub 3} mixed aqueous solution as sacrificial agent. The ternary CdS/g-C{sub 3}N{sub 4}/CuS composites show the enhanced visible-light photocatalytic H{sub 2}-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C{sub 3}N{sub 4} in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H{sub 2}-production activity.

  13. Enhancement of the atomic absorbance of Cr, Zn, Cd, and Pb in metal furnace atomic absorption spectrometry using absorption tubes

    Directory of Open Access Journals (Sweden)

    Yuya Koike

    2017-03-01

    Full Text Available Trace amounts of Cr, Zn, Cd, and Pb were determined by metal furnace atomic absorption spectrometry using absorption tubes. Various absorption tubes were designed as roof- and tube-types, and fixed above the metal furnace in order to extend the light path length. Aqueous standards and samples were injected in the metal furnace and atomized in a metal atomizer with an absorption tube (6 cm length, 15.5 mm diameter. The used of an absorption tube resulted in an enhancement of the atomic absorbance. The ratios of absorbance values with and without the roof- and tube-type absorption tubes were 1.33 and 1.11 for Cr; 1.42 and 1.99 for Zn; 1.66 and 1.98 for Cd; and 1.31 and 1.16 for Pb, respectively. The use of an absorption tube was effective for Zn and Cd analysis, as the absorbance values for these low boiling point metals doubled. The proposed method was successfully applied in the determination of Zn in tap water.

  14. Cu{sup 2+}, Co{sup 2+} and Cr{sup 3+} doping of a calcium phosphate cement influences materials properties and response of human mesenchymal stromal cells

    Energy Technology Data Exchange (ETDEWEB)

    Schamel, Martha [Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, 97070 Würzburg (Germany); Bernhardt, Anne; Quade, Mandy; Würkner, Claudia [Centre for Translational Bone, Joint and Soft Tissue Research, University Hospital Carl Gustav Carus and Faculty of Medicine of Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden (Germany); Gbureck, Uwe; Moseke, Claus [Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, 97070 Würzburg (Germany); Gelinsky, Michael [Centre for Translational Bone, Joint and Soft Tissue Research, University Hospital Carl Gustav Carus and Faculty of Medicine of Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden (Germany); Lode, Anja, E-mail: anja.lode@tu-dresden.de [Centre for Translational Bone, Joint and Soft Tissue Research, University Hospital Carl Gustav Carus and Faculty of Medicine of Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden (Germany)

    2017-04-01

    The application of biologically active metal ions to stimulate cellular reactions is a promising strategy to accelerate bone defect healing. Brushite-forming calcium phosphate cements were modified with low doses of Cu{sup 2+}, Co{sup 2+} and Cr{sup 3+}. The modified cements released the metal ions in vitro in concentrations which were shown to be non-toxic for cells. The release kinetics correlated with the solubility of the respective metal phosphates: 17–45 wt.-% of Co{sup 2+} and Cu{sup 2+}, but < 1 wt.-% of Cr{sup 3+} were released within 28 days. Moreover, metal ion doping led to alterations in the exchange of calcium and phosphate ions with cell culture medium. In case of cements modified with 50 mmol Cr{sup 3+}/mol β-tricalcium phosphate (β-TCP), XRD and SEM analyses revealed a significant amount of monetite and a changed morphology of the cement matrix. Cell culture experiments with human mesenchymal stromal cells indicated that the observed cell response is not only influenced by the released metal ions but also by changed cement properties. A positive effect of modifications with 50 mmol Cr{sup 3+} or 10 mmol Cu{sup 2+} per mol β-TCP on cell behaviour was observed in indirect and direct culture. Modification with Co{sup 2+} resulted in a clear suppression of cell proliferation and osteogenic differentiation. In conclusion, metal ion doping of the cement influences cellular activities in addition to the effect of released metal ions by changing properties of the ceramic matrix. - Highlights: • A brushite-forming calcium phosphate cement was modified by doping with bioactive Cu{sup 2+}, Co{sup 2+} and Cr{sup 3+} ions. • The metal ions were integrated in the cement matrix, setting was not affected. • The modified cements released the metal ions in doses non-toxic for cells. • Modification with Cr{sup 3+} ions enhanced the biocompatibility of the cement.

  15. Influence of Al and the heavy metals Fe, Mn, Zn, Cu, Pb, and Cd on development and efficacy of vesicular-arbuscular mycorrhiza in tropical and subtropical plants. Einfluss von Al und den Schwermetallen Fe, Mn, Zn, Cu, Pb und Cd auf die Effizienz der VA-Mykorrhiza bei tropischen und subtropischen Pflanzen

    Energy Technology Data Exchange (ETDEWEB)

    Fabig, B.

    1982-07-08

    In greenhouse experiments the influence of Al and the heavy metals Fe, Mn, Zn, Cu, Pb, and Cd on the efficacy of VA-mycorrhizal fungi was tested with special regard to several soil pH levels and soil water regimes in different combinations. The most important results were: The inoculation led to a significantly better growth of all test plants in the presence of Al, Fe, Mn, Zn, Cu, Pb, and Cd up to a specific amount of the soil-applied element; beyond this specific limit the efficacy of the mycorrhiza was more or less inhibited depending on the element. In correlation with the growth, the nearly always better P uptake of the inoculated plants was impaired only by the highest toxic amounts of the elements. In comparison with the uninoculated plants, all the inoculated plants showed higher P and Pb concentrations. The mycorrhizal plants generally had significantly higher concentrations of the elements Al, Mn, Zn, Cu, and Cd in the roots than the uninoculated plants. Generally even toxic levels of Fe in the soil did not lead to higher Fe concentrations in the plants. Even the highest amounts of Al, Fe, Mn, Zn, and Cu did not cause microscopically visible injuries to the development of the mycorrhiza and did not impede the infection. Only the toxic levels of Pb led to a decrease of the infection rate of about 50%. Pb and Cd were the reason for morphological changes of the different developmental phases of the fungus. High amounts of Pb induced an increased formation of vesicles. The highest amounts of Cd were accompanied by the crowded occurrence of arbuscules.

  16. Removal of Pb(II), Cu(II) and Cd(II) from aqueous solution by some fungi and natural adsorbents in single and multiple metal systems

    International Nuclear Information System (INIS)

    Shoaib, A.; Badar, T.; Aslam, N.

    2011-01-01

    Six fungal and 10 natural biosorbents were analyzed for their Cu(II), Cd(II) and Pb(II) uptake capacity from single, binary and ternary metal ion system. Preliminary screening biosorption of assays revealed 2 fungi (Aspergillus niger and Cunninghamella echinulata) and three natural [Cicer arietinum husk, Moringa oleifera flower and soil (clay)] adsorbents hold considerable high adsorption efficiency and capacity for 3 meta l ions amongst the adsorbents. Further biosorption trials with five elected adsorbents showed a considerable reduction in metal uptake capability of adsorbents in binary- and ternary systems as compared to singly metal system. Cd(II) manifested the highest inhibitory effect on the biosorption of other metal ions, followed by Pb(II) and Cu(II). On account of metal preference, the selectivity order for metal ion towards the studied biomass matrices was Pb(II) (40-90%) > Cd(II) (2-53%) > Cu(II) (2-30%). (author)

  17. Determination of Cr and Cd concentration adsorbed by chicken feathers

    International Nuclear Information System (INIS)

    Lopez M, A.; Cuapio O, L.A.; Cardenas P, S.; Balcazar, M.; Jauregui, V.; Bonilla P, A.

    2008-01-01

    In this work the results of the samples analysis of chicken feathers are presented, used as adsorber of the heavy metals Cd and Cr present in water solutions with well-known concentrations of these metals. It was used the Neutron Activation Analysis technique (AAN), using the TRIGA Mark-III reactor of the Nuclear Center of Mexico. The obtained results they show the advantages of having a versatile installation for the analysis of this type of samples. By means of the analysis of the results, it was determined the feasibility of using chicken feathers like adsorber of these metals present in polluted waters, additionally, it was detected the presence of others polluting elements in the inputs to prepare the reference solutions as well as in the processes, so much of preparation of the feathers like of the metals adsorption. (Author)

  18. Heavy metal levels and solid phase speciation in street dusts of Delhi, India

    International Nuclear Information System (INIS)

    Banerjee, Anju D.K.

    2003-01-01

    Although the street dusts of Delhi contain considerably high levels of Cr, Ni, Cu, Cd, Zn and Pb, solid phase speciation results indicate comparatively limited environmental mobility and bioavailability of Ni and Cr. - Street dust samples were collected from three different localities (industrial, heavy traffic and rural) situated in the greater Delhi area of India. The samples analyzed for Cd, Zn, Pb, Ni, Cu, and Cr indicated remarkably high levels of Cr, Ni, and Cu in the industrial area, whilst Pb and Cd did not show any discernible variations between the three localities. A multivariate statistical approach (Principal Component Analysis) was used to define the possible origin of metals in dusts. The street dusts were sequentially extracted so that the solid pools of Cd, Zn, Pb, Ni, Cu, Cr could be partitioned into five operationally defined fractions viz. exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter and residual. Metal recoveries in sequential extractions were ±10% of the independently measured total metal concentrations. Cd was the only metal present appreciably (27.16%) in the exchangeable fraction and Cu was the only metal predominantly associated (44.26%) with organic fraction. Zn (45.64%) and Pb (28.26%) were present mainly in the Fe-Mn oxide fraction and the residual fraction was the most dominant solid phase pool of Cr (88.12%) and Ni (70.94%). Assuming that the mobility and bioavailability are related t