WorldWideScience

Sample records for cd cu cr

  1. Geospatial Mapping of Pb, Cr, Cu, Zn, Cd, and Sb in Urban Soil, Cd. Juarez, Chihuahua, Mexico

    Science.gov (United States)

    Amaya, M. A.; Grimida, S. E.; Elkekli, A. R.; Aldouri, R. K.; Benedict, B. A.; Pingitore, N. E., Jr.

    2015-12-01

    Population-based random stratified sampling of the city of Cd. Juarez, Chihuahua, Mexico provided 500 city blocks for study. We collected soil from the public space (where present) in front of each house on a selected block; equal measured small volumes of these were combined to produce a composite sample for analysis. Such composite samples (1) decrease, by an order of magnitude, laboratory processing and analysis costs, and (2) smooth the data to represent blocks as averages of individual houses. Retention of the unanalyzed samples of the individual houses permits their later analysis should the composites suggest further study of individual houses on an anomalous block. Elemental analysis of 10 mg pressed powders was performed on a Panalytical Epsilon5 EDS-XRF, via 8 secondary targets and 12 USGS and NIST multi-element rock standards. The mean and (range) of concentration for Pb was 43 (13-550) ppm; for Cr, 31 (1.8-76); for Cu, 22 (6-550); for Zn 84 (42-415) ppm; for Cd, 1.9 (0.1-6.2); and for Sb, 5.9 (2.7-29). The old urban core of Cd. Juarez was marked by high levels of Pb, Cr, Cu, and Zn, and, to a smaller degree, of Cd and Sb. This pattern mirrors that of contiguous El Paso, Texas, USA, directly across the narrow Rio Grande. Businesses, industrial facilities, transportation (both railroads and highways), traditional "downtown" shopping, and old residential districts cluster in this urban core. A Pb-Cu-Zn smelter, which operated for more than a century until 1999, is present in the US adjacent to the Rio Grande, about two km away from downtown Cd. Juarez. Thus the city has been subject to both traditional metal sources (e.g., leaded gasoline, highway debris) and smelter emissions. The poplation of Cd. Juarez has exploded in the last few decades to some 1.5 million inhabitants due both to natural growth and in-migration from rural districts for economic opportunity. Most of this growth has been accommodated by radial expansion of the city into the surrounding

  2. Bioaccumulation of Pb, Cd, Cu, and Cr by Porphyridium cruentum (S.F. Gray Nägeli

    Directory of Open Access Journals (Sweden)

    Tri Retnaningsih Soeprobowati

    2013-06-01

    Full Text Available The red microalgae Porphyridium cruentum (S.F. Gray Nägeli usually was used as feeds, a pigment for food and cosmetic, and antiviral activity that might be became industrial interest. Similar to another microalgae, P. cruentum has an ability to remediate heavy metals pollution, however research on it still limited. This research was conducted in order to find out the the accumulation of Pb, Cd, Cr, and Cu on the P. cruentum. A laboratory experiment were developed with different concentrations. Based on this research, P. cruentum with the treatment of 1 mg/L had reduced higher Cu, Pb, Cd, and Cr concentrations rather than 3 and 5 mg/L concentrations, respectively. This was also similar to the BCF, that in day 8 in order of Cu > Cr > Cd > Pb, respectively; however, in day 15 was Cu > Pb > Cd > Cr. The length of treatment influenced BCF value. P. cruentum was good for bioremediation of heavy metal pollution, with the advantage of the short of accumulation time.

  3. The level and bioaccumulation of Cd, Cu, Cr and Zn in benthopelagic species from the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    SHI Ronggui; LIN Jing; YE Yi; MA Yifan; CAI Minggang

    2015-01-01

    The Bering Sea is an area of high biological productivity, with large populations of sea-birds, demersal and pelagic fishes, so it seemed desirable to assess the bioaccumulation of trace metals in the marine organisms from this area. However, few data on trace metal concentrations are available for the benthopelagic organisms from the Bering Sea till now. Ten specimens of benthos (including 120 biological samples) were collected in the western Bering Sea in August 2008 during the 3rd Chinese National Arctic Research Expeditions, and the concentration of Cd, Cu, Cr and Zn determined using atomic absorption spectrometry. Zn, Cr and Cd concentrations in muscle tissues of the crab species were much higher than those from fish and cephalopod species, and the highest concentration of Cu was observed in the muscle tissues ofCylichna nucleoli. The results showed a similar hierarchy for Zn, Cr, Cd and Cu concentrations among different tissues as follows: hepatopancreas>muscle tissue>gonad. Bioconcentration factors indicated that benthic organisms had high accumulation abilities for Zn and Cu.

  4. 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)

    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

  5. First-Principles Study of Doped Half-Metallic Spinels: Cu0.5Zn0.5Cr2S4,Cu0.5Cd0.5Cr2S4, Li0.5Zn0.5Cr2O4 and Li0.5Zn0.5Cr2S4

    Institute of Scientific and Technical Information of China (English)

    ZHOU Tie-Ge; LIU Zhi-Qiang; ZUO Xu

    2012-01-01

    Electronic structure and magnetic properties of Cu0.5 Zn0.5 Cr2S4, Cu0.5 Cd0.5 CrS4, Li0.5 Zn0.5 CrO4 and Li0.5 Zn0.5 Cr2S4 are investigated using the first-principles calculation based on the density functional theory. GGA+U exchange correlation is used in the calculation to correct the effective Coulomb repulsion energy of Cr underestimated by LSDA or GGA. The calculation results reveal that half-metallic Cu0.5 Zn0.5 Cr2S4 and Cu0.5 Cd0.5 CrS4 can be achieved by doping CuCr2S4 with Zn or Cd, though CuCr2S4 is not half-metallic. Half-metallic LiCr2O4 is experimentally unstable, but half-metallic Li0.5 Zn0.5 Cr2O4 and Li0.5 Zn0.5 Cr2S4 can be achieved by doping Li into experimentally stable ZnCr2O4 and ZnCr2S4, though ZnCr2O4 and ZnCr2S4 are not half-metallic. The influence of +U on the electronic structure and half-metallicity of the doped systems is also presented.%Electronic structure and magnetic properties of Cu0.5 Zn0.5 Cr2S4,Cu0.5 5 Cd0.5 Cr2S4,Li0.5 Zn0.5 Cr2O4 and Li0.5 Zn0.5 Cr2S4 are investigated using the first-principles calculation based on the density functional theory.GGA +U exchange correlation is used in the calculation to correct the effective Coulomb repulsion energy of Cr underestimated by LSDA or GGA.The calculation results reveal that half-metallic Cu0.5Zn0.5Cr2S4 and Cu0.5Cd0.5Cr2S4 can be achieved by doping CuCr2S4 with Zn or Cd,though CuCr2S4 is not half-metallic.Half-metallic LiCr2O4 is experimentally unstable,but half-metallic Li0.5Zn0.5 Cr2O4 and Li0.5Zn0.5 Cr2S4 can be achieved by doping Li into experimentally stable ZnCr2O4 and ZnCr2S4,though ZnCr2O4 and ZnCr2S4 are not half-metallic.The influence of +U on the electronic structure and half-metallicity of the doped systems is also presented.

  6. Photocatalytic removal of M2+ (=Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Ag+) over new catalyst CuCrO2

    International Nuclear Information System (INIS)

    The metal ions M2+ (Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Ag+) are potentially toxic. Their electro deposition has been carried out in aqueous air-equilibrated CuCrO2 suspension upon visible illumination. The delafossite CuCrO2 is p-type semiconductor characterized by a low band gap (1.28 eV) and a long-term chemical stability. The corrosion rate is found to be 10-2 μmol m-2 month-1 in aqua regia. The oxide has been elaborated through nitrate route where the specific surface area is increased via the surface/bulk ratio. A correlation exists between the dark M2+ adsorption, the redox potential of M2+/0 couple and the conduction band of CuCrO2 positioned at -1.06 VSCE. Ag+ cannot be photoreduced because of its positive potential located far above the valence band. By contrast, Zn2+ is efficiently deposited due to the large driving force at the interface. The improved photoactivity of copper with a deposition percentage (90%) is attributed to the strong dark adsorption onto the surface catalyst. The results indicate a competitive effect with the water reduction; it has been observed that the M2+ deposition goes parallel with the hydrogen evolution. Such behavior is attributed to the low H2 over voltage when ultra fine aggregate of M islands are photodeposited onto CuCrO2 substrate

  7. Photocatalytic removal of M(2+) (Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Ag(+)) over new catalyst CuCrO(2).

    Science.gov (United States)

    Ketir, W; Bouguelia, A; Trari, M

    2008-10-30

    The metal ions M(2+) (Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Ag(+)) are potentially toxic. Their electro deposition has been carried out in aqueous air-equilibrated CuCrO(2) suspension upon visible illumination. The delafossite CuCrO(2) is p-type semiconductor characterized by a low band gap (1.28 eV) and a long-term chemical stability. The corrosion rate is found to be 10(-2) micromol m(-2)month(-1) in aqua regia. The oxide has been elaborated through nitrate route where the specific surface area is increased via the surface/bulk ratio. A correlation exists between the dark M(2+) adsorption, the redox potential of M(2+/0) couple and the conduction band of CuCrO(2) positioned at -1.06 V(SCE). Ag(+) cannot be photoreduced because of its positive potential located far above the valence band. By contrast, Zn(2+) is efficiently deposited due to the large driving force at the interface. The improved photoactivity of copper with a deposition percentage (90%) is attributed to the strong dark adsorption onto the surface catalyst. The results indicate a competitive effect with the water reduction; it has been observed that the M(2+) deposition goes parallel with the hydrogen evolution. Such behavior is attributed to the low H(2) over voltage when ultra fine aggregate of M islands are photodeposited onto CuCrO(2) substrate. PMID:18384943

  8. Physiological characterization of Chlamydomonas reinhardtii acclimated to chronic stress induced by Ag, Cd, Cr, Cu and Hg ions.

    Science.gov (United States)

    Nowicka, Beatrycze; Pluciński, Bartosz; Kuczyńska, Paulina; Kruk, Jerzy

    2016-08-01

    Acclimation to heavy metal-induced stress is a complex phenomenon. Among the mechanisms of heavy metal toxicity, an important one is the ability to induce oxidative stress, so that the antioxidant response is crucial for providing tolerance to heavy metal ions. The effect of chronic stress induced by ions of five heavy metals, Ag, Cu, Cr (redox-active metals) Cd, Hg (nonredox-active metals) on the green microalga Chlamydomonas reinhardtii was examined at two levels - the biochemical (content of photosynthetic pigments and prenyllipid antioxidants, lipid peroxidation) and the physiological (growth rate, photosynthesis and respiration rates, induction of nonphotochemical quenching of chlorophyll fluorescence). The expression of the genes which encode the enzymes participating in the detoxification of reactive oxygen species (APX1, CAT1, FSD1, MSD1) was measured. The other gene measured was one required for plastoquinone and α-tocopherol biosynthesis (VTE3). The application of heavy metal ions partly inhibited growth and biosynthesis of chlorophyll. The growth inhibition was accompanied by enhanced lipid peroxidation. An increase in the content of prenyllipid antioxidants was observed in cultures exposed to Cr2O7(2-), Cd(2+) (α- and γ-tocopherol and plastoquinone) and Cu(2+) (only tocopherols). The induction of nonphotochemical quenching was enhanced in cultures exposed to Cu(2+), Cr2O7(2-) and Cd(2+), as compared to the control. Chronic heavy metal-induced stress led to changes in gene expression dependent on the type and concentration of heavy metal ions. The up-regulation of antioxidant enzymes was usually accompanied by the up-regulation of the VTE3 gene. PMID:27104807

  9. Contribution to heavy metal monitoring (Zn, Cd, Hg, Cu, Ag, Pb, Cr, Ni) at the Baltic coast of Schleswig-Holstein using common mussels (1988/89)

    International Nuclear Information System (INIS)

    Heavy metal concentrations (Zn, Cd, Hg, Cu, Ag, Pb, Cr, Ni) in common mussels were measured at various sites along the Baltic coast of Schleswig-Holstein during different seasons in the period from 1988 to 1989. Measurements of heavy metal load in the summer of 1988/89 showed that Zn concentrations (150-900 μg.g-1) were the highest at all monitoring stations. Hg, Cu, and Ag levels were distinctly elevated and Pb levels only moderately so. Cd, Cr, and Ni levels were largely lower than the aforementioned. A comparison with data of 1979 show a marked rise in Hg levels at all stations and a more or less distinct upward trend for Cr, Zn, Ag, and Ni. Cd levels have markedly declined since 1975/76. (orig.)

  10. 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...... average 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....

  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 C...

  12. Heavy Metals (Cd, Cu, Cr, Pb and Zn) in Meretrix meretrix Roding, Water and Sediments from Estuaries in Sabah, North Borneo

    Science.gov (United States)

    Abdullah, Mohd. Harun; Sidi, Jovita; Aris, Ahmad Zaharin

    2007-01-01

    Concentrations of heavy metals (Cd, Cu, Cr, Pb and Zn) in tissues of Meretrix meretrix Roding (M. meretrix R.), water and sediments from two estuaries were determined. One estuary is located in an urban area of Kota Kinabalu (Likas estuary) and the other in a rural district of Kota Belud (Kota Belud estuary), where both are in Sabah, North of…

  13. Removal of Heavy Metals Fe3+, Cu2+, Zn2+, Pb2+, Cr3+ and Cd2+ from Aqueous Solutions by Using Eichhornia Crassipes

    Directory of Open Access Journals (Sweden)

    S.A. Shama

    2010-01-01

    Full Text Available The adsorption capacity of Eichhornia Crassipes towards metal ions such as Fe3+, Cu2+, Zn2+, Pb2+, Cr3+ and Cd2+, was studied. The adsorption capacity was investigated by batch experiments. The results showed that the removal percentages increased as the weight of sorbent increased, except for Fe3+ and Zn2+. The effect of contact time was also studied and the results showed that the removal percentages increased as the contact time increased for Cr3+, Zn2+ and Pb2+, but for Fe3+, Cu2+ and Cd2+ the removal decreased. The effect of pH of the solution was also studied and the removal percentages increased as pH increased. Also the effect of the initial concentration of metal ions was studied at four different concentrations (5, 10, 30, 50 mg/L; in case of metal ions (Cu2+, Zn2+ and Cd2+ the removal percentages increased by increasing initial concentration. But, for the other metal ions it decreased by increasing initial concentration over 30 mg/L. The order of increasing removal percentages of metal ions at pH=4.86, initial concentration of metal ions 30 mg/L, and after four hours of shaking was: Cu2+< Cr3+ <Cd2+< Zn2+

  14. 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)

    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

  15. Toxicity and critical body residues of Cd, Cu and Cr in the aquatic oligochaete Tubifex tubifex (Müller) based on lethal and sublethal effects.

    Science.gov (United States)

    Méndez-Fernández, Leire; Martínez-Madrid, Maite; Rodriguez, Pilar

    2013-12-01

    The aim of the present study was to estimate critical body residues (CBRs) of three metals [cadmium (Cd), copper (Cu), chromium (Cr)] in the aquatic oligochaete Tubifex tubifex based on lethal (LBR) and sublethal effects (CBR), and to discuss the relevance of the exposure to sediment for deriving CBR. Toxicity parameters (LC50, EC50, LBR50 and CBR50) were estimated for each metal by means of data on survival and on several sublethal variables measured in short-term (4 days), water-only exposures and in long-term, chronic (14 and 28 days) exposures using metal-spiked sediment. Sublethal endpoints included autotomy in short-term exposure, as well as reproduction and growth in chronic bioassays. LBR50 and CBR50 were 3-6 times higher in sediment than in water-only exposure to Cd and about 2-11 times higher for Cu, depending on the measured endpoint; however, for Cr these parameters varied only by a factor of 1.2. Cu and Cr LBR50 and CBR50 values in 96 h water-only exposure were very similar (survival 2.39 μmol Cu g(-1) dw, 2.73 μmol Cr g(-1) dw; autotomy 0.53 μmol Cu g(-1) dw, 0.78 μmol Cr g(-1) dw). However, in metal-spiked sediments, 28 d CBR50 values for autotomy, reproduction and growth ranged 6.76-29.54 μmol g(-1) dw for Cd, 3.88-6.23 μmol g(-1) dw for Cu, 0.65 μmol g(-1) dw for Cr (calculated only on total number of young). Exposure conditions (time and presence/absence of sediment) seem to be influential in deriving metal CBR values of Cd and Cu, while appear to be irrelevant for Cr. Thus, CBR approach for metals is complex and tissue residue-toxicity relationship is not directly applicable so far. PMID:24085604

  16. 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.

  17. Cd, Cr, Cu, Pb, and Zn concentrations in Ulva lactuca, Codium fragile, Jania rubens, and Dictyota dichotoma from Rabta Bay, Jijel (Algeria).

    Science.gov (United States)

    Laib, Essaid; Leghouchi, Essaid

    2012-03-01

    Concentrations of Cd, Cr, Cu, Pb, and Zn were determined in algae samples collected from the Rabta Bay in the Mediterranean Sea, Algeria. The levels of heavy metals in the macroalgae, Ulva lactuca, Codium fragile (green algae), Jania rubens (red algae), and Dictyota dichotoma (brown algae) recorded high concentrations except for Cd. Moreover, Zn was the most predominant metal in the seaweeds. The obtained HM contents indicate that different species demonstrate various degree of metal accumulation and the obtained higher values in site 1 of the studied zone can be attributed to the discharge influence of two rivers (Mouttas and Larayeche Rivers), entering the Mediterranean Sea and local pollutant emissions. The abundance of heavy metal concentrations in the macroalgae samples was found in the order below: Zn > Cu > Pb > Cr > Cd from the studied zone. The highest amounts of heavy metals in algae samples were Cd, Cu, and Pb in brown algae, and Cr and Zn in green and brown algae from the studied zone (Rabta Bay). PMID:21755430

  18. Proficiency test PLANTS 8 - determination of As, Cd, Cr, Cu, Hg, Pb, Se and Zn in dry carrot root powder

    International Nuclear Information System (INIS)

    Proficiency test PLANTS 8: determination of As, Cd, Cr, Cu, Hg, Pb, Se and Zn in dry carrot root powder has been described. The proficiency test has been provided by the Institute of Nuclear Chemistry and Technology with cooperation with POLLAB-CHEM/EURACHEM-PL and REFMAT Society according to ISO/IEC Guide 43-1:1997 and IUPAC International Harmonized Protocol (2006). Testing material was prepared from home-grown carrots which were air dried, milled and sieved. Particle fraction below 0.5 mm was collected and bottled in 20 g portions. Homogeneity testing shown that the material was homogenized for sample mass at least 250 mg. Assigned (reference) values and their uncertainties were established on the basis of the results of analysis provided by 3 reference laboratories. The testing samples were send to 25 laboratories participating in the proficiency test. 24 laboratories had send results. The results supplied by the participants were statistically evaluated. Values of z-score, zeta-score and En numbers were used for the evaluation of the participating laboratory performance. (authors)

  19. Chelatization of Metals Ion (Cu2+, Cd2+ and Cr3+) with ProcessYield of Humic Acid from Peat Soil

    International Nuclear Information System (INIS)

    The chelation of metals ion (Cu2+, Cd2+ and Cr3+) with processyields of humic acid from peat soil has been done. The chelatizationcalculation was carried out using a mathematical model of the metals ionneutralization to the humic acid functional group. The model has superioritydue to the introduction of the humic acid concentration conditional and theloading capacity. Chelation is expected to obtain the constant experimentthat agrees with environmental conditional were the chelatization to takeplaces. By the tree neck flask of bath reactor, 250 ml volume at thetemperature of 25 oC chelation have been done and the AAS was used toanalyzes the yield. By mathematical calculate was obviously proved that thechelation constants was not influenced by pH, ionic strength and origin peatsoils. As log β, chelation constants of Cu2+, Cd2+ and Cr3+ were4.67 (± 0.02); 5.98 (± 0.02) and 6.09 (± 0.01) for humic acid fromSumatra I (Silaut III) and 4.68 (± 0.01); 5.97 (± 0.02) and 6.09 (±0.02) for Sumatra II (Silaut IV). While chelation constant Cu2+, Cd2+ andCr3+ from Kalimantan were 4.66 (± 0.03); 5.99 (± 0.01); 6.08 (±0.02). (author)

  20. 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)

    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)

  1. Effect of carbon content in biolithes on Cd(II), Zn(II), Ni(II), Cu(II) and Cr(III) ions uptake

    Energy Technology Data Exchange (ETDEWEB)

    Kyziol-Komosinska, J. [Polska Akademia Nauk, Zabrze (Poland)

    2007-10-15

    Three Polish peats (porosity 0.26-0.59, specific surface 10.78-14.10 m{sup 2}/g, C content 52.93-60.96%) and a lignite (porosity 0.42, specific surface 9.98 m{sup 2}/g, C content 66.79%) were used as sorbents for removal Cd, Zn, Ni, Cu, and Cr ions from an aqueous solution at 22{sup o}C to determine the sorption isotherms. The sorption capacity increased with the increasing C content in the sorbents except for the Cr{sup 3+} ions showing a low affinity to the lignite used.

  2. 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.

  3. Determination of heavy metals (Pd, Cd, Cu, Zn, Cr) in sedimentary reference materials with IDMS: Total concentration and aqua regia soluble portion

    Energy Technology Data Exchange (ETDEWEB)

    Goetz, A.; Heumann, K.G.

    1988-12-01

    The total concentration and the aqua regia soluble portion of traces of Pb, Cd, Cu, Zn, and Cr are determined with isotope dilution mass spectrometry (IDMS) in three different types of sediments using a thermal quadrupole instrument (THQ). The results are compared with those obtained by other methods during a certification project to establish these sediments (BCR 277, BCR 280, BCR 320) as standard reference materials. The IDMS (THQ) results are in good agreement with the preliminary certification values and the results of two other laboratories, which applied IDMS using magnetic sector field mass spectrometers. Significant differences between the different analytical methods were found for the total Pb concentration, which could be explained by adsorption and coprecipitation effects during the chemical pretreatment of samples. Using aqua regia instead of HF/HNO/sub 3/ for the decomposition of sediments, only 65%-95% of the total Pb and 60%-90% of the total Cr could be dissolved. On the other hand, only a small or negligible portion of Zn, Cd, and Cu could not be dissolved by aqua regia. The IDMS values for the aqua regia soluble Cr portion are significantly higher compared to the results of other methods. This can be explained by adsorption effects.

  4. determination of (Cd, As, Pb, Zn, Cr, and Cu) in the flesh tissues of some kinds of marine beings at the shore of Lattakia city by AAS

    International Nuclear Information System (INIS)

    Trace heavy metals in two sort of Bivalvia and five kind of fish has been determined in comparison with water samples using atomic absorption spectroscopy method. The results showed high concentration of studied elements (Cd, As, Pb, Zn, Cr, and Cu) in the animal samples compared with the water samples and is close to the concentration of some other elements , where these concentrations reached their highest value in the Bivalvia since it has the water filtration property. Nevertheless these concentrations are still approximate with their concentrations in other parts of the Mediterranean basin and within the known limits of these elements in the marine environment. (author)

  5. Effect of EDTA, EDDS, NTA and citric acid on electrokinetic remediation of As, Cd, Cr, Cu, Ni, Pb and Zn contaminated dredged marine sediment.

    Science.gov (United States)

    Song, Yue; Ammami, Mohamed-Tahar; Benamar, Ahmed; Mezazigh, Salim; Wang, Huaqing

    2016-06-01

    In recent years, electrokinetic (EK) remediation method has been widely considered to remove metal pollutants from contaminated dredged sediments. Chelating agents are used as electrolyte solutions to increase metal mobility. This study aims to investigate heavy metal (HM) (As, Cd, Cr, Cu, Ni, Pb and Zn) mobility by assessing the effect of different chelating agents (ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid (EDDS), nitrilotriacetic acid (NTA) or citric acid (CA)) in enhancing EK remediation efficiency. The results show that, for the same concentration (0.1 mol L(-1)), EDTA is more suitable to enhance removal of Ni (52.8 %), Pb (60.1 %) and Zn (34.9 %). EDDS provides effectiveness to increase Cu removal efficiency (52 %), while EDTA and EDDS have a similar enhancement removal effect on As EK remediation (30.5∼31.3 %). CA is more suitable to enhance Cd removal (40.2 %). Similar Cr removal efficiency was provided by EK remediation tests (35.6∼43.5 %). In the migration of metal-chelate complexes being directed towards the anode, metals are accumulated in the middle sections of the sediment matrix for the tests performed with EDTA, NTA and CA. But, low accumulation of metal contamination in the sediment was observed in the test using EDDS. PMID:26782321

  6. Determination of trace heavy metals (Cd, As, Pb, Zn, Cr, Cu) in some fish species from the coast of Tartous city by (AAS)

    International Nuclear Information System (INIS)

    This study deals with the concentrations of six trace heavy metals (Cd, As, Pb, Zn, Cr, Cu) in the flesh of four edible fish species including: Mugil, siganus Luridus, Siganus rivulatus and Sardine species, in addition to water samples for comparison. The samples were taken from three sites near to the sea-shore of Tartous city, on the eastern coast of the Mediterranean. The method used in this study depends on the determination of the above trace mentioned metals using (AAS) according to two techniques (Flame - AAS) and (ETA - AAS), after wet-digestion for the animal samples, and the two extraction methods (APDC - MIBK) and (APDC - CHCl3) for water samples. The study showed that the highest value was recorded in the case of Zn (29.44 μg/g, wet weight), and the lowest one was recorded in the case of Cd (0.082 μg/g, wet weight) in the flesh tissues of Mugil species. Recording standard deviation (SD), it was clear that the highest value was 1.145 μg/g for Zn, and lowest one was 0.001 μg/g for Cd in Mugil species. In order to get some information about the distribution of the studied elements, we studied the correlation coefficient. The statistical study showed a variation from a high positive relation, to low, and sometimes to negative ones. This gives a clear indication that the increasing or decreasing ratios in the concentration of the studied elements in the marine environment is related to the pollution resulting from the different sources of human activity. By comparing the results of this research with other results within and outside the Mediterranean basin, we observed a decrease in the concentration of (Cd, As, Pb, Cr, Cu) elements. and an increase in the concentration of Zn element. (Author)

  7. Biomonitoring of trace metals (Cu, Cd, Cr, Hg, Pb, Zn in Mali Ston Bay (eastern Adriatic using the Mediterranean blue mussel (1998-2005

    Directory of Open Access Journals (Sweden)

    Tomislav ZVONARIĆ

    2007-06-01

    Full Text Available In Mali Ston Bay, located on the eastern Adriatic coast, mussels and oysters have traditionally been cultivated. However, previous studies showed that water and sediments from Mali Ston Bay contain elevated levels of some trace metals, which was attributed to natural processes of sedimentation and drainage. In order to assess the bioavailability of trace metals in the bay, and to assess the health risk of consumption of shellfish species from Mali Ston Bay, a passive monitoring program was carried out in the period from December 1998 to August 2005. Samples of the whole soft tissue were collected seasonally at 4 shellfish breeding farms and analyzed for essential (Cu, Zn and non-essential (Cd, Cr, THg, Pb metals. Mean concentrations of analyzed metals in the edible tissue of mussels (Cd: 1.15 mg kg-1 d.wt.; Cr: 1.65 mg kg-1 d.wt.; Cu: 5.6 mg kg-1 d.wt.; THg: 0.15 mg kg-1 d.wt.; Pb: 1.09 mg kg-1 d.wt.; Zn: 139 mg kg-1 d.wt. fell in the range of values usually found in low to moderately contaminated marine coastal areas. Examination of the spatial pattern of contaminants showed that there were no statistically significant differences among stations in Mali Ston Bay regarding trace metal content. Concentrations of Cd, Cu, Cr and THg were significantly higher during the autumn-winter period, while concentrations of Pb and Zn did not depend on the sampling season. Among six analyzed metals, only concentrations of Cd and THg were significantly negatively correlated with the condition index of the mussels. Analysis of temporal trends during the 7 years of monitoring showed that metal concentrations had not changed with time. According to EU and WHO legislation, consumption of the edible tissue of the mussels was not harmful for humans since all the values were well below the permissible limits for fresh seafood. In addition, results of the evaluation of the risks to human health associated with consumption of the mussels containing trace metals suggest

  8. 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.

  9. 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)

    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)

  10. 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.

    Science.gov (United States)

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

    2012-10-01

    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 > Cu ~ Cr ~ Cd > 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. PMID:22705504

  11. Time saving modified BCR sequential extraction procedure for the fraction of Cd, Cr, Cu, Ni, Pb and Zn in sediment samples of polluted lake

    International Nuclear Information System (INIS)

    The mobility, availability and persistence of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in contaminated lake sediment samples were evaluated by means of sequential extraction scheme, proposed by the Community Bureau of Reference protocol (BCR). The metal content in the extracts was measured by atomic absorption spectrometry. The precision and accuracy of the proposed procedure were evaluated by using a certified reference material BCR 701. The maximum recoveries for heavy metals (HMs) were observed for all three steps of BCR protocol at 32 h total shaking period instead of previously reported 51 h, with p > 0.05. The lixiviation tests (DIN 38414-S4) were used to evaluate the leaching of HMs from sediment samples and it was observed that levels of water extractable HMs were low as compared to those values obtained by acid-soluble fraction of the BCR protocol

  12. 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)

    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.

  13. Use of neutralized industrial residue to stabilize trace elements (Cu, Cd, Zn, As, Mo, and Cr) in marine dredged sediment from South-East of France.

    Science.gov (United States)

    Taneez, Mehwish; Marmier, Nicolas; Hurel, Charlotte

    2016-05-01

    Management of marine dredged sediments polluted with trace elements is prime issue in the French Mediterranean coast. The polluted sediments possess ecological threats to surrounding environment on land disposal. Therefore, stabilization of contaminants in multi-contaminated marine dredged sediment is a promising technique. Present study aimed to assess the effect of gypsum neutralized bauxaline(®) (bauxite residue) to decrease the availability of pollutants and inherent toxicity of marine dredged sediment. Bauxaline(®), (alumia industry waste) contains high content of iron oxide but its high alkalinity makes it not suitable for the stabilization of all trace elements from multi-contaminated dredged sediments. In this study, neutralized bauxaline(®) was prepared by mixing bauxaline(®) with 5% of plaster. Experiments were carried out for 3 months to study the effect of 5% and 20% amendment rate on the availability of Cu, Cd, Zn, As, Mo, and Cr. Trace elements concentration, pH, EC and dissolved organic carbon were measured in all leachates. Toxicity of leachates was assessed against marine rotifers Brachionus plicatilis. The Results showed that both treatments have immobilization capacity against different pollutants. Significant stabilization of contaminants (Cu, Cd, Zn) was achieved with 20% application rate whereas As, Mo, and Cr were slightly stabilized. Toxicity results revealed that leachates collected from treated sediment were less toxic than the control sediment. These results suggest that application of neutralized bauxaline(®) to dredged sediment is an effective approach to manage large quantities of dredged sediments as well as bauxite residue itself. PMID:26894678

  14. Chemical fractionation of Cu, Zn, Cd, Cr, and Pb in sewage sludge amended soils at the end of 65-d sorghum-sudan grass growth.

    Science.gov (United States)

    Sivapatham, Paramasivam; Lettimore, Jon M; Alva, Ashok K; Jayaraman, Kuppuswamy; Harper, Legia M

    2014-09-19

    Heavy metals are potentially toxic to human life and the environment. Metal toxicity depends on chemical associations in soil. Understanding the chemical association of trace elements in soils amended with biosolids is very important since it determines their availability within rhizosphere and mobility beyond the rhizosphere. A sequential extraction method was used to determine the various chemical associations [labile (exchangeable + sorbed), organic, carbonates, and sulfides] of Cu, Zn, Cd, Cr, and Pb at the end of sorghum-sudan grass growth (65d) in Candler fine sand (pH = 6.8) and in Ogeechee loamy sand (pH = 5.2) amended with wastewater treatment sludge (WWTS) obtained from two different sources at application rates of 0, 24.7, 49.4, 98.8, and 148.2 Mg ha(-1). Results of this study indicated that irrespective of the soil type, Cu, Cd, Cr, and Pb in the labile fractions (exchangeable + sorbed) were in the range of 0-3.0 mg kg(-1) and the amount for Zn was in the range of 0.2-6.6 mg kg(-1). Therefore, their availability to plants and mobility beyond rhizosphere would be substantially low unless further transformations occur from other fractions. Results also indicated that the presence of substantial amounts of trace elements studied were in sulfide (HNO3) fraction and in organic (NaOH) fraction irrespective of soil type with the exception of Pb which was mainly present as carbonate (Na2EDTA) fraction and the remaining Pb equally as sulfide (HNO3) and organic (NaOH) fractions. Furthermore, results indicated that Cd was mainly present as carbonate (Na2EDTA) fraction. Irrespective of soil type, source and rate of WWTS application, summation of quantities of various fractions of all the trace elements studied through sequential extraction procedure were 1 to 25 % lower than that of total recoverable quantities of these trace elements determined on acid digestion described by US EPA method 3050 B. It was further evident that growing sorghum sudan grass for 65-d

  15. Environmental behaviors and potential ecological risks of heavy metals (Cd, Cr, Cu, Pb, and Zn) in multimedia in an oilfield in China.

    Science.gov (United States)

    Hu, Yan; Wang, Dazhou; Li, Yu

    2016-07-01

    The environmental behaviors of five heavy metals (Cd, Cr, Cu, Pb, and Zn) in a Chinese oilfield were investigated using a steady-state multimedia aquivalence (SMA) model. The modeling results showed good agreement with the actual measured values, with average residual errors of 0.69, 0.83, 0.35, 0.16, and 0.54 logarithmic units for air, water, soil, sediment, and vegetation compartments, respectively. Model results indicated that most heavy metals were buried in sediment, and that transfers between adjacent compartments were mainly deposition from the water to the sediment compartment (48.59 %) and from the air to the soil compartment (47.74 %) via atmospheric dry/wet deposition. Sediment and soil were the dominant sinks, accounting for 68.80 and 25.26 % of all the heavy metals in the multimedia system, respectively. The potential ecological risks from the five heavy metals in the sediment and soil compartments were assessed by the potential ecological risk index (PERI). The assessment results demonstrate that the heavy metals presented low levels of ecological risk in the sediment compartment, and that Cd was the most significant contributor to the integrated potential ecological risk in the oilfield. The SMA model provided useful simulations of the transport and fate of heavy metals and is a useful tool for ecological risk assessment and contaminated site management. PMID:27040543

  16. 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 (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. PMID:26201657

  17. 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)

    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/m3), while in the three sites the annual average was higher than the maximum annual permissible level (75 μg/m3) 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 urban

  18. Nuclear and related analytical methods applied to the determination of Cr, Ni, Cu, Zn, Cd and Pb in a red ferralitic soil and Sorghum samples

    International Nuclear Information System (INIS)

    Several studies on the influence of heavy metals to the growth of vegetables have been carried out in Cuba by the Ministry of Agriculture in order to evaluate the effects resulting of the continuous application of fertilizers and other materials to the soils. The analysis of metal contents in soil and vegetable samples is often troublesome due to the low concentration levels to be determined. In the present work EDXRF, AAS and ASV methods were applied and compared for the evaluation of Cr, Ni, Cu, Zn, Cd and Pb contents in red ferralitic soil and Sorghum samples. Several certified reference materials (CRM) (inorganic and organic matrixes) were analyzed in order to evaluate the performance of the analytical procedures and the bias and precision of the results. A study was performed with growing Sorghum in several series of pots where different quantities of metals were added to the soil substrate. The observed correlation between the metal contents in soil and plants as well as the influence of different additions of each metal on the plant growth is also presented. (author)

  19. The Uptake Mechanism of Cd(II, Cr(VI, Cu(II, Pb(II, and Zn(II by Mycelia and Fruiting Bodies of Galerina vittiformis

    Directory of Open Access Journals (Sweden)

    Dilna Damodaran

    2013-01-01

    Full Text Available Optimum concentrations of heavy metals like copper, cadmium, lead, chromium, and zinc in soil are essential in carrying out various cellular activities in minimum concentrations and hence help in sustaining all life forms, although higher concentration of these metals is lethal to most of the life forms. Galerina vittiformis, a macrofungus, was found to accumulate these heavy metals into its fleshy fruiting body in the order Pb(II > Cd(II > Cu(II > Zn(II > Cr(VI from 50 mg/kg soil. It possesses various ranges of potential cellular mechanisms that may be involved in detoxification of heavy metals and thus increases its tolerance to heavy metal stress, mainly by producing organic acids and phytochelatins (PCs. These components help in repairing stress damaged proteins and compartmentalisation of metals to vacuoles. The stress tolerance mechanism can be deduced by various analytical tools like SEM-EDX, FTIR, and LC-MS. Production of two kinds of phytochelatins was observed in the organism in response to metal stress.

  20. The Uptake Mechanism of Cd(II), Cr(VI), Cu(II), Pb(II), and Zn(II) by Mycelia and Fruiting Bodies of Galerina vittiformis

    Science.gov (United States)

    Damodaran, Dilna; Balakrishnan, Raj Mohan; Shetty, Vidya K.

    2013-01-01

    Optimum concentrations of heavy metals like copper, cadmium, lead, chromium, and zinc in soil are essential in carrying out various cellular activities in minimum concentrations and hence help in sustaining all life forms, although higher concentration of these metals is lethal to most of the life forms. Galerina vittiformis, a macrofungus, was found to accumulate these heavy metals into its fleshy fruiting body in the order Pb(II) > Cd(II) > Cu(II) > Zn(II) > Cr(VI) from 50 mg/kg soil. It possesses various ranges of potential cellular mechanisms that may be involved in detoxification of heavy metals and thus increases its tolerance to heavy metal stress, mainly by producing organic acids and phytochelatins (PCs). These components help in repairing stress damaged proteins and compartmentalisation of metals to vacuoles. The stress tolerance mechanism can be deduced by various analytical tools like SEM-EDX, FTIR, and LC-MS. Production of two kinds of phytochelatins was observed in the organism in response to metal stress. PMID:24455671

  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)

    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. Solid-liquid-solid extraction of heavy metals (Cr, Cu, Cd, Ni and Pb) in aqueous systems of zeolite-sewage sludge

    International Nuclear Information System (INIS)

    This paper presents results of kinetic and equilibrium studies of the removal of heavy metals (Cr, Cu, Cd, Ni and Pb) from the sewage sludge using a new technique of solid-liquid-solid extraction with the adsorption-diffusion column filled by the zeolite. The metal extraction onto the zeolite from aqueous solution of the clinoptilolite and the sludge composition is characterized by three stages: intensive extraction, inversion and stabilization with the moderate extraction increase. Addition of 25% of the zeolite provides extraction efficiency of cadmium and lead of about 84%, chromium, copper and nickel of 66%, 61% and 50%, respectively. The estimated values of Gibbs free energy change ΔG show that the metals extraction by the clinoptilolite may be considered as a physical adsorption. The negative values of ΔG testify to an exothermic nature of the process. The difference between energetic potentials of the components is a driving force of the metal redistribution in the system 'clinoptilolite-water-sludge'

  3. Investigation of heavy metal (Cu, Pb, Cd, and Cr) stabilization in river sediment by nano-zero-valent iron/activated carbon composite.

    Science.gov (United States)

    Chen, Wei-fang; Zhang, Jinghui; Zhang, Xiaomao; Wang, Weiya; Li, Yuxiang

    2016-01-01

    Nano-zero-valent iron/activated carbon (nZVI/AC) composite was evaluated for its effectiveness in the stabilization of Cu, Pb, Cd, and Cr in dredged river sediment. Synthetic precipitation leaching procedure (SPLP) and toxicity characteristic leaching procedure (TCLP) were adopted to compare the effects of nZVI/AC dosage, particle size, time duration, and temperature on heavy metal leachability. The results show that leachability dropped considerably with the addition of nZVI/AC and powdered particles in the size of 0.075-0.18 mm was more effective in stabilization than granular ones. Stabilization effect was stable in long-term and robust against changes in temperature. Tessier sequential extraction revealed that heavy metals were associated with solid particle, inorganic or organic matters in sediment. The addition of nZVI/AC was able to convert relatively weakly bound heavy metals into more strongly bound species and thus reduce the bioavailability and toxicity. Also, the standard potential of heavy metals may decide the mechanism of stabilization process. PMID:26370818

  4. 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)

    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)

  5. 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

  6. Chemical speciation of Fe, Mn, Pb, Zn, Cd, Cu, Co, Ni and Cr in the suspended particulate matter off the Mejerda River Delta (Gulf of Tunis, Tunisia)

    Science.gov (United States)

    Helali, Mohamed Amine; Oueslati, Walid; Zaaboub, Noureddine; Added, Ayed; Aleya, Lotfi

    2016-06-01

    Fluxes of suspended particulate matter (SPM) and their associated metals were performed off the Mejerda River Delta during both the wet (March) and the dry (July) seasons in 2012, using sediment traps at study stations at depths of 10, 20 and 40 m. Fluxes nearest to the Mejerda outlet were more significant, especially during winter (36 g m-2 day-1), but dissipated further offshore, 24.5-6 g m-2 day-1 at the 20 m and 21.8-4.8 g m-2 day-1 at the 40 m stations. Many variations observed in seasonal and spatial metal fluxes are similar to those of SPM, in particular Pb and Zn, probably because they are associated with the mining activity characteristic of the Mejerda catchment. Chemical speciation reveals that most of the metals (20-100%) are bound to the residual fraction. The most toxic metals (Pb, Zn) are bound in part to the exchangeable fraction (20-50% for Pb and 5-15% for Zn) making them relatively bioavailable and therefore potentially toxic. While Cu and Cd fluxes are not always clearly established according to season, both metals are apparently sequestered deep in the sediment, bound especially to clays (40-80% for Cd and up to 100% for Cu).

  7. Photocatalytic reduction of Cr(VI) on the novel hetero-system CuFe2O4/CdS

    International Nuclear Information System (INIS)

    The photocatalytic HCrO4- reduction was investigated in air equilibrated solution using the spinel CuFe2O4 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 (C7H6O3 + 6 O2 + 4 h+ + 3 H2O → 7 CO2 + 4 H3O+). Evidence has been given to show the advantages of the hetero-system CuFe2O4/CdS in the chromate reduction. CuFe2O4 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 ∼2.8 h and a quantum yield of ∼0.12% for an initial HCrO4- concentration of 3 x 10-4 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 cm3 mn-1 g-1 in presence and in absence of HCrO4-, respectively.

  8. 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.

  9. Explosive compaction of CuCr alloys

    Institute of Scientific and Technical Information of China (English)

    李金平; 罗守靖; 龚朝晖; 牛玮; 纪松

    2002-01-01

    The production of CuCr alloys utilizing explosive compaction was studied. Mixture powders of CuCr alloys placed in tubes with a dimension of d14.0mm×21.4mm can be compacted using explosive pads of 16.5mm or 22.5mm. Thicker pads of explosive make the compacts more porous. The effects of the ratio of me/mp, ratio of me/(mp+mt) and impact energy on the density of compacts were similar, they were chosen to control explosive compaction, respectively. When adequate value of the parameters me/mp, me/(mt+mp) and impact energy of unit area of tube was chosen, high density(7.858g/cm3), high hardness(HB189) and low conductance (13.6MS/m) of CuCr alloys could be made by explosive compaction. The general properties of CuCr alloys by explosive compaction are similar to those of CuCr alloys by traditional process.

  10. Chemometric evaluation of Cd, Co, Cr, Cu, Ni (inductively coupled plasma optical emission spectrometry) and Pb (graphite furnace atomic absorption spectrometry) concentrations in lipstick samples intended to be used by adults and children.

    Science.gov (United States)

    Batista, Érica Ferreira; Augusto, Amanda dos Santos; Pereira-Filho, Edenir Rodrigues

    2016-04-01

    A method was developed for determining the concentrations of Cd, Co, Cr, Cu, Ni and Pb in lipstick samples intended to be used by adults and children using inductively coupled plasma optical emission spectrometry (ICP OES) and graphite furnace atomic absorption spectrometry (GF AAS) after treatment with dilute HNO3 and hot block. The combination of fractional factorial design and Desirability function was used to evaluate the ICP OES operational parameters and the regression models using Central Composite and Doehlert designs were calculated to stablish the best working condition for all analytes. Seventeen lipstick samples manufactured in different countries with different colors and brands were analyzed. Some samples contained high concentrations of toxic elements, such as Cr and Pb, which are carcinogenic and cause allergic and eczematous dermatitis. The maximum concentration detected was higher than the permissible safe limits for human use, and the samples containing these high metal concentrations were intended for use by children. Principal component analysis (PCA) was used as a chemometrics tool for exploratory analysis to observe the similarities between samples relative to the metal concentrations (a correlation between Cd and Pb was observed). PMID:26838401

  11. 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%. PMID:26073519

  12. 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)

    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)

  13. Synthesis and characterization of Cu-Cr-O nanocomposites

    Institute of Scientific and Technical Information of China (English)

    LI Wei; CHENG Hua

    2007-01-01

    Cu-Cr-O nanocomposites that can be used as additives for the catalytic combustion of AP(ammonium perchlorate)-based solid-state propellants were synthesized via a citric acid(CA) complexing approach. Techniques of TG-DTA, XRD as well as TEM were employed to characterize the thermal decomposition procedure, crystal phase, micro-structural morphologies and grain size of the as-synthesized materials respectively. The results show that well-crystallized Cu-Cr-O nanocomposites can be produced after the CA-Cu-Cr precursors are calcined at 500 ℃ for 3 h. Phase composition of the as-obtained Cu-Cr-O nanocomposites depends on the molar ratio of Cu to Cr in the starting reactants. Addition of the as-synthesized Cu-Cr-O nanocomposites as catalysts enhances the burning rate as well as lowers the pressure exponent of the AP-based solid-state propellants considerably. Noticeably, catalyst with a Cu/Cr molar ratio of 0.7 exhibits promising catalytic activity with high burning rate and low pressure exponent at all pressures, due to the effective phase interaction between the spinel CuCr2O4 and delafossite CuCrO2 contained in the as-synthesized Cu-Cr-O nanocomposites.

  14. Structural and magnetic properties of Cu Ni Cr spinel oxides

    Science.gov (United States)

    Tovar, M.; Torabi, R.; Welker, C.; Fleischer, F.

    2006-11-01

    The compounds CuCr 2O 4 and NiCr 2O 4 crystallize at room temperature in a tetragonal distorted spinel structure, s.g. I4 1/amd, with axes ratio c/ a1, respectively. The distortion is caused by the Jahn-Teller ions Cu 2+ and Ni 2+ which flatten or elongate their surrounding oxygen tetrahedron. CuCr 2O 4 and NiCr 2O 4 form a complete solid solution series Cu 1-xNi xCr 2O 4 where for 0.825NiCr 2O 4). The phase Cu 0.15Ni 0.85Cr 2O 4 undergoes a second crystallographic transition to orthorhombic symmetry, space group Fddd, at T=300 K. The neutron diffraction experiments as well as SQUID measurements reveal magnetic ordering of the ions between 150 and 50 K which partially occurs as a two-step mechanism.

  15. A comparative study of eld emission properties of Cu, Cr, and CrN

    CERN Document Server

    Muranaka, T; Leifer, K; Ziemann, V

    2012-01-01

    We investigated the field emission properties of Cu, Cr, and CrN by using the field emission measurement setup inside a scanning electron microscope at the Angstrom laboratory in Uppsala University, from 11th to 13th January 2012.

  16. Evaluation of Ti-Cr-Cu alloys for dental applications

    Science.gov (United States)

    Koike, Marie; Okabe, Toru; Itoh, Masayuki; Okuno, Osamu; Kimura, Kohei; Takeda, Osamu; Okabe, Toru H.

    2005-12-01

    This study examined the characteristics of as-cast Ti-Cr(7 19%)-Cu(3 7%) (all percentages in this article are mass%) alloys to evaluate their suitability for dental applications; studies on the alloy structures and mechanical properties, grindability, and corrosion behavior were included in the investigation. The alloys were centrifugally cast and bench-cooled in investment molds. The x-ray diffractometry of the as-cast alloys bench-cooled in the molds indicated the following phases: α+β+ω in the 7% Cr and 7% Cr+3% Cu; β+ω in the 13%Cr; and β in the 13%Cr+3% Cu through the 19%Cr+3% Cu alloys. The strengths of the binary β Ti-Cr and ternary β Ti-Cr-Cu alloys with 13 and 19% Cr were approximately two times higher than those of CP Ti. The alloy ductility was dependent on the chemical composition and thus, the microstructure. The 7% Cr alloys were extremely brittle and hard due to the ω phase, but the ductility was restored in the 13 and 19% Cr alloys. The hardness (HV) of the cast 13 and 19% Cr alloys was approximately 300 350 compared with a value of 200 for CP Ti. The grindability of the cast alloys was examined using a rotating SiC wheel at speeds (circumferential) of 500 and 1250 m/min. At the higher speed, the grindability of the 13 and 19% Cr alloys increased with the Cu content. The grindability of the 13% Cr alloy with 7% Cu was similar to that of CP Ti. Evaluation of the corrosion behavior in an artificial saliva revealed that the alloys are like many other titanium alloys within the normal intraoral oxidation potential. The wear resistance testing of these alloys also showed favorable results.

  17. Effect of Alloying Interlayer on Interfacial Bond Strength of CuW/CuCr Integral Materials

    International Nuclear Information System (INIS)

    The effects of Fe alloying interlayers with different content on microstructures and mechanical properties of dissimilar CuW/CuCr joints prepared by sintering-infiltration method were studied. Microhardness (HV) and tensile tests were used to evaluate the mechanical properties of the resulting joints. Additionally, optical, scanning electron microscopy examinations and energy dispersive spectrometry elemental analyses were applied to determine the interfacial characteristics of CuW/CuCr integral materials. The results show element Fe in the alloying interlayers is mostly diffused to the Cu-W composite side, the Cu/W interphase has achieved the metallurgical bond, and the CuW/CuCr integrated material with Cu-5wt%Fe alloy interlayer exhibits higher interfacial bond strength. However, when the Fe content in the interlayers is above 5wt%, the W skeletons near the interface are dissolved and eroded by element Fe addition, the amount of eutectic phase is increased and the microhardness on copper matrix is decreased for the Cu-Cr alloy side near the interlayer, and the interfacial strength of CuW/CuCr integrated materials is also decreased.

  18. 微波消解-原子吸收法快速测定羽毛中的铜锌铬铅镉%Rapid determination of Cu,Zn, Cr,Pb and Cd in feather by microwave digestion-atomic absorption spectrometry method

    Institute of Scientific and Technical Information of China (English)

    黎鲜茗; 周西林

    2013-01-01

    提出了微波消解原子吸收法测定改性羽毛中铜、锌、铬、铅、镉的分析方法.采用在密闭容器中,用HNO3和HClO4混酸做溶剂在微波状态下消解改性羽毛样品,样品溶解完毕泄压后,定容,用快速序列分析功能的原子吸收仪同时测定铜、锌、铬、铅、镉的含量,快速高效.同时考察了微波消解称样量、溶剂用量及共存离子对分析结果的影响,其标准样品的测定结果与标准值一致.本法适应于改性羽毛中铜、锌、铬、铅、镉的测定.%The contents of Cu, Zn, Cr, Pb and Cd in modified feather were determined by microwave digestion-atomic absorption spectrometry method. The feather was dissolved by mixture of HN03 and HClO4 under microwave. The contents of Cu, Zn, Cr, Pb and Cd were rapid determined by atomic absorption spectrometry after decompression and constant volume. The effects of sample weight by microwave digestion, solvents and coexisting ions on analyzed results were discussed. The results showed that the determination was in accord with standard which is available for determination of Cu, Zn, Cr, Pb and Cd in modified feather.

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

    International Nuclear Information System (INIS)

    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 CuCl2 either into CdTe layer or into back contact carbon layer. Cell parameters of the sintered CdS/CdTe solar cells which contained various amounts of CuCl2 in the CdTe layers before sintering stay at about the same values as the amount of CuCl2 increases up to 25 ppm, and then decreases sharply as the amount of CuCl2 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 CuCl2 in the CdTe layer before sintering. A sintered CdS/CdTe solar cell which contained 25 ppm CuCl2 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/cm2

  20. Thermoelectric properties of Cu and Cr disordered CuCrX2(X=S, Se): a first principles study.

    Science.gov (United States)

    Srivastava, Divya; Tewari, Girish C; Karppinen, Maarit

    2014-12-17

    The layered antiferromagnetic ACrX(2) -type compounds are currently highlighted as prominent material candidates for low- and intermediate-temperature thermoelectric (TE) applications. A key to attain the enhanced TE characteristics is to apply high-temperature sintering which presumably introduces some cation disorder. Here we present spin unrestricted density functional theory analysis of electronic band structures and TE properties of Cu and Cr disordered CuCrX(2)(X = S, Se) phases. A narrow band gap semiconductor to metal transition is observed on 8.3% Cr-site disorder for both the compounds, X = S and Se. The large p-type Seebeck coefficient realized in the metallic state for the Cr-disordered phases is the factor that makes these phases promising TE materials. These theoretical findings for the Cr-disordered phases are well in line with reported experimental data for electronic transport properties. Contrarily, the results revealed for the Cu-disordered phases do not agree with the experimental data. Hence the results of our theoretical analysis strongly point towards the Cr rather than the Cu disorder picture to explain the TE electronic transport characteristics of the high-temperature sintered phases of CuCrX(2)(X = S, Se). PMID:25406713

  1. β-Cyclodextrin assisted solubilization of Cu and Cr complexes of flavonoids in aqueous medium: A DNA-interaction study

    Science.gov (United States)

    Jabeen, Erum; Janjua, Naveed Kausar; Hameed, Shahid

    2014-07-01

    Cu and Cr complexes of three flavonoids (morin, quercetin and 6-hydroxyflavone) were synthesized and included in beta-cyclodextrin (βCD) with the objective of improving their pharmacokinetic profiles. Then binding with ds.DNA was studied to monitor their interactive tendencies at physiological conditions. The binding constants and other thermodynamic data from UV-vis spectroscopy and cyclic voltammetry revealed Cr-flavonoid-βCD to interact with ds.DNA at pH-7.4 through electrostatic mode of binding while Cu-flavonoid-βCD can intercalate into DNA. The strong binding propensity of Cu-flavonoid-βCD with ds.DNA encourages their application as anticancerous agent.

  2. Photoluminescence of Cu-doped CdTe and related stability issues in CdS/CdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Grecu, D. [University of Toledo, Toledo, Ohio 43606-3390 (United States); Compaan, A. D. [University of Toledo, Toledo, Ohio 43606-3390 (United States); Young, D. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Jayamaha, U. [First Solar LLC., Perrysburg, Ohio 43551 (United States); Rose, D. H. [First Solar LLC., Perrysburg, Ohio 43551 (United States)

    2000-09-01

    We explore Cu electronic states in CdTe using photoluminescence as the main investigative method. Our results are consistent with some Cu atoms occupying substitutional positions on the Cd sublattice and with others forming Frenkel pairs of the type Cu{sub i}{sup +}-V{sub Cd}{sup -} involving an interstitial Cu and a Cd vacancy. In addition, we find that Cu-doped CdTe samples exhibit a significant ''aging'' behavior, attributable to the instability of Cu acceptor states as verified by our Hall measurements. The aging appears to be reversible by a 150-200 degree sign C anneal. Our results are used to explain efficiency degradation of some CdTe solar-cell devices which use Cu for the formation of a backcontact. (c) 2000 American Institute of Physics.

  3. Study on improvement of conductivity of Cu-Cr-Zr alloys

    Institute of Scientific and Technical Information of China (English)

    LI Huaqing; XIE Shuisheng; WU Pengyue; MI Xujun

    2007-01-01

    The influence of alloying, heat treatment, and plastic working on the performance of Cu-Cr-Zr alloys was investigated. The precipitated phases were characterized as Cr, Cu51Zr14 and Cu5Zr. Cu-Cr-Zr alloys demonstrate combination properties of high strength and high conductivity after solution treatment, aging treatment, and plastic deformation. Precipitation course of Cr is the main factor that influences the conductivity of Cu-Cr-Zr alloys, while adding Zr in the alloys adjusts the orientation relationship between Cr and matrix, and tends to increase the conductivity of aged Cu-Cr-Zr alloys after deformation.

  4. Cu Migration in Polycrystalline CdTe Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Da [Arizona State University; Akis, Richard [Arizona State University; Brinkman, Daniel [Arizona State University; Sankin, Igor [First Solar; Fang, Tian [First Solar; Vasileska, Dragica [Arizona State University; Ringhofer, Christian [Arizona State University

    2014-03-12

    An impurity reaction-diffusion model is applied to Cu defects and related intrinsic defects in polycrystalline CdTe for a better understanding of Cu’s role in the cell level reliability of CdTe PV devices. The simulation yields transient Cu distributions in polycrystalline CdTe during solar cell processing and stressing. Preliminary results for Cu migration using available diffusivity and solubility data show that Cu accumulates near the back contact, a phenomena that is commonly observed in devices after back-contact processing or stress conditions.

  5. Microstructures and properties of Cr-Cu/W-Cu bi-layer composite coatings prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiaping; Feng, Xiaomei; Shen, Yifu; Chen, Cheng; Duan, Cuiyuan [Nanjing Univ. of Aeronautics and Astronautics (China). Dept. of Materials Science and Technology

    2016-06-15

    Cr-Cu/W-Cu bi-layer coatings with composite structures were fabricated by means of mechanical alloying. The Cr-Cu layer and the W-Cu layer were deposited successively and the as-synthesized bi-layer coating was made up of an inner Cr-Cu layer and an outer W-Cu layer. Microstructures, chemical and phase compositions of the as-prepared coatings were characterized. The results indicated that the bonding between the inner coating and the substrate was improved with the increase of Cu in the raw powder. The annealing treatment of the inner Cr-Cu layer was beneficial to the bonding between the inner Cr-Cu coating and the outer W-Cu coating layer. Mechanical properties such as microhardness, friction and wear resistance were tested. The as-synthesized coating could effectively improve the hardness and wear resistance of the Cu substrate.

  6. New roles for icosahedral clusters in intermetallic phases: micelle-like segregation of Ca-Cd and Cu-Cd interactions in Ca10Cd27Cu2.

    Science.gov (United States)

    Hadler, Amelia B; Harris, Nicholas A; Fredrickson, Daniel C

    2013-11-20

    Despite significant progress in the structural characterization of the quasicrystalline state, the chemical origins of long- and short-range icosahedral order remain mysterious and a subject of debate. In this Article, we present the crystal structure of a new complex intermetallic phase, Ca10Cd27Cu2 (mC234.24), whose geometrical features offer clues to the driving forces underlying the icosahedral clusters that occur in Bergman-type quasicrystals. Ca10Cd27Cu2 adopts a C-centered monoclinic superstructure of the 1/1 Bergman approximant structure, in which [110] layers of Bergman clusters in the 1/1 structure are separated through the insertion of additional atoms (accompanied by substantial positional disorder). An examination of the coordination environments of Ca and Cu (in the ordered regions) reveals that the structure can be viewed as a combination of coordination polyhedra present in the nearest binary phases in the Ca-Cd-Cu compositional space. A notable feature is the separation of Ca-Cd and Cu-Cd interactions, with Bergman clusters emerging as Ca-Cd Friauf polyhedra (derived from the MgZn2-type CaCd2 phase) encapsulate a Cu-Cd icosahedron similar to those appearing in Cu2Cd5. DFT chemical pressure calculations on nearby binary phases point to the importance of this segregation of Ca-Cd and Cu-Cd interactions. The mismatch in atomic size between Cu and Cd leads to an inability to satisfy Ca-Cu and Ca-Cd interactions simultaneously in the Friauf polyhedra of the nearby Laves phase CaCd2. The relegation of the Cu atoms to icosahedra prevents this frustration while nucleating the formation of Bergman clusters. PMID:24147875

  7. Friction and Wear Property of Cu-Cr Alloy

    Institute of Scientific and Technical Information of China (English)

    Liu Jianhua; Wang Yuhui; Gao Hong; Zhang Ruijun

    2007-01-01

    The friction and wear behaviors of the Cu-Cr alloy sliding against GCr15 steel at different loads and rotate speed conditions were evaluated, and the worn surface morphologies were observed on a scanning electron microscope. Results show that as loads and rotate speed increase, the wear loss weight increases, by comparison, the biggest friction coefficient of Cu-Cr alloy was obtained at load 100N and rotate speed at 100 r·min-1 friction condition. Moreover, the dominant wear forms was plough wear.

  8. Photoluminescence of Cu-doped CdTe and related stability issues in CdS/CdTe solar cells

    Science.gov (United States)

    Grecu, D.; Compaan, A. D.; Young, D.; Jayamaha, U.; Rose, D. H.

    2000-09-01

    We explore Cu electronic states in CdTe using photoluminescence as the main investigative method. Our results are consistent with some Cu atoms occupying substitutional positions on the Cd sublattice and with others forming Frenkel pairs of the type Cui+-VCd- involving an interstitial Cu and a Cd vacancy. In addition, we find that Cu-doped CdTe samples exhibit a significant "aging" behavior, attributable to the instability of Cu acceptor states as verified by our Hall measurements. The aging appears to be reversible by a 150-200 °C anneal. Our results are used to explain efficiency degradation of some CdTe solar-cell devices which use Cu for the formation of a backcontact.

  9. Effect of Lanthanum and Yttrium on Microstructures of Cu-Cr alloys

    Institute of Scientific and Technical Information of China (English)

    Chen Xiaofang; Zhang Meng; Yin Jianying; Shuai Gewang; Liu Guoming

    2004-01-01

    Microstructures of Cu-based alloys (including Cu0.8Cr0.05La, Cu0.8Cr0.1La, Cu0.8Cr0.4La, Cu0.8Cr0.05Y,Cu0.8Cr0.1Y and Cu0.8Cr0.4Y) were studied by optical microscope, X-ray diffractometer, Scanning electron microscope and Energy-dispersive X-ray spectroscopy. The results show that La and Y refine the grains and change the distribution of microstructures of Cu-Cr alloys. The sizes of Cr particles are smaller in CuCrRE alloys than in CuCr alloy. In CuCrLa and CuCrY alloys, La and Y usually respectively exist as compounds of Cu6La and Cu5Y. These compounds distribute in the grains with sphere shape and on the grain-boundaries with slice shape.

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

    International Nuclear Information System (INIS)

    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 E1, E1 + Δ1, and E2 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 Cu2−xTe 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

  11. Thermomechanical Processing and Roll Bonding of Tri-Layered Cu-Ni-Zn/Cu-Cr/Cu-Ni-Zn Composite

    Science.gov (United States)

    Kim, Hobyung; Kang, Gyeong Tae; Hong, Sun Ig

    2016-05-01

    Tri-layered Cu-Ni-Zn/Cu-Cr/Cu-Ni-Zn composite was processed by roll bonding and the effect of thermomechanical processing on the mechanical performance and electrical conductivity was studied. Roll-bonded composite exhibited the brief work hardening and subsequent rapid work softening because of the high stored deformation energy, leading to failure at the plastic strain of 8 to 10 pct. The mechanical instability of as-roll-bonded composites was abated by heat treatment (HT) at 723 K (450 °C) and the extended work hardening with enhanced ductility compared to that of the as-roll-bonded composites was observed after HT. The strength and electrical conductivity of clad composite is dependent on the precipitation strengthening of Cu-Cr and recovery softening of Cu-Ni-Zn during post-roll-bonding HT. The increase of roll-bonding temperature enhances the precipitation kinetics and it takes shorter time to reach maximum hardness in Cu-Cr layer during post-roll-bonding HT. The toughness of as-roll-bonded Cu-Ni-Zn/Cu-Cr/Cu-Ni-Zn clad composite at 773 K (500 °C) [42 MJ/mm3] is greater than those at 723 K (450 °C) [24 MJ/mm3] and 823 K (550 °C) [38 MJ/mm3]. The maximum toughness [100 MJ/mm3] with the electrical conductivity of 68 pct IACS was obtained in the Cu-Ni-Zn/Cu-Cr/Cu-Ni-Zn clad composite roll-bonded at 773 K (500 °C) and subsequently heat-treated at 723 K (450 °C).

  12. Corrosion behavior of CuCrNiAl alloy in HCl solutions

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The corrosion behavior of a CuCrNiAl alloy in HCl solutions was studied by means of metallograph, XRD, SEM/EDX and TEM methods. The results show that in low concentration of HCl solutions, Cu of CuCrNiAl alloy is more easily subject to corrsion than Cr; the dechromisation of the CuCrNiAl alloy occurs at a certain concentration of HCl solutions, at the same time Al of CuCrNiAl alloy is subject to corrosion also. The dechromisation corrosion occurs initially at the interface between Cr phase and Cu phase, then it gradually extends Cr phase until Cr phase is dissolved completely. It is also revealed that the tendency of dechromisaion of the CuCrNiAl alloy increases with the increase in concentration and temperature of HCl solutions.

  13. Structural study of Cu-Cr mechanical alloying powders

    International Nuclear Information System (INIS)

    The changes of grain size, micro strain, stacking fault probability, stacking fault energy and dislocations density on powder mixtures of copper with 1 and 3 weights after higher energy mechanical milling. The X-ray diffraction profile was analysed by Williamson-Hall (W-H) method. Grain size decreased with the increase of milling time, until values of 106 and 59 nm for 1 and 3 weight % Cr, respectively. As well micro strain increased with milling time. Stacking fault probability increased in function of milling time to value between 1x10''-3 -8x10''-3 for Cu-1 weighty Cr and 3x10''-3 -8x10''-3 for Cu-3 weight % Cr. The stacking fault energy decreased with milling time and amount of chromium. Finally, the dislocations density is between 1x10''14 -1x10''15 m/m''3. (Author) 29 refs

  14. Electrical Characterization of Cu Composition Effects in CdS/CdTe Thin-Film Solar Cells with a ZnTe:Cu Back Contact: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Li, J. V.; Duenow, J. N.; Kuciauskas, D.; Kanevce, A.; Dhere, R. G.; Young, M. R.; Levi, D. H.

    2012-07-01

    We study the effects of Cu composition on the CdTe/ZnTe:Cu back contact and the bulk CdTe. For the back contact, its potential barrier decreases with Cu concentration while its saturation current density increases. For the bulk CdTe, the hole density increases with Cu concentration. We identify a Cu-related deep level at {approx}0.55 eV whose concentration is significant when the Cu concentration is high. The device performance, which initially increases with Cu concentration then decreases, reflects the interplay between the positive influences and negative influences (increasing deep levels in CdTe) of Cu.

  15. Nonradiative recombination processes in (CdTe, CdCrTe)/CdMgTe quantum well structures

    International Nuclear Information System (INIS)

    Photoluminescence transitions in (CdTe,CdCrTe)/CdMgTe structure grown by molecular beam epitaxy are studied. Photoluminescence investigations show a very strong reduction of the photoluminescence intensity from chromium doped quantum wells. We explain this fact by a very efficient nonradiative recombination in the chromium-doped quantum wells. The present results indicate that the Auger-type energy transfer from excitons to chromium ions is responsible for the photoluminescence deactivation. The efficiency of this process is evaluated. (author)

  16. Interaction of Mg with heavy metals (Cu, Cd) in T. aestivum with special reference to oxidative and proline metabolism.

    Science.gov (United States)

    Singh, Vijeta; Tripathi, Bhumi Nath; Sharma, Vinay

    2016-05-01

    Little effort has been made to understand the influence of Mg on cellular processes of plant cell during Cu and Cd toxicities. The present work demonstrates the influence of magnesium (Mg) on copper (Cu) and cadmium (Cd) toxicity on Triticum aestivum (Wheat). We measured a range of parameters related to oxidative stress in wheat exposed to Cu or Cd toxicity in media with different concentrations of Mg. Decreasing Mg concentration significantly exacerbated Cu and Cd toxicity and optimum supply of Mg improved the growth and decreased the toxicity-induced oxidative stress (a substantial decline in the amount of hydrogen peroxide (H2O2) and malondialdehyde (MDA) in root and shoot tissues). Activity of antioxidant enzymes-superoxide dismutase (SOD), ascorbae peroxidase (APX), catalase (CAT) was restored upon optimum Mg concentration in the presence of Cu and Cd toxicity. An increase in proline concentration in roots and shoots that was triggered by Cu and Cd exposure was partly reversed. This was due to decline in pyrroline-5-carboxylate synthetase (P5CS) and pyrroline-5-carboxylate reductase (P5CR) activity and enhanced proline dehydrogenase (PDH) activity. In conclusion, decreasing supply of Mg effectively exacerbated the toxicities of Cu and Cd in wheat. PMID:26547559

  17. Electronic structure and band alignments of ZnTe/CrTe(0 0 1), CdSe/CrTe(0 0 1) and CdTe/CrTe(0 0 1) interfaces

    Indian Academy of Sciences (India)

    F Ahmadian; R Zare

    2011-08-01

    All-electron full potential calculations based on spin density functional theory were performed to study cubic zincblende (ZB) and hexagonal NiAs structures of bulk CrTe and ZnTe/CrTe(0 0 1), CdTe/CrTe(0 0 1) and CdSe/CrTe(0 0 1) interfaces. The lattice mismatch effect in ZB CrTe and magnetic properties of CrTe in the ideal ZB CrTe structure were investigated. The band alignment properties of the ZnTe/CrTe(0 0 1), CdTe/CrTe(0 0 1) and CdSe/CrTe(0 0 1) interfaces were computed and a rather large minority valence band offset of about 1.09 eV was observed in ZnTe/CrTe(0 0 1) heterojunction. Also in the CdTe/CrTe(0 0 1) and CdSe/CrTe(0 0 1) interfaces, the conduction band minimum of minority spin in CrTe was above the conduction band minimum of CdTe and CdSe and so the majority spin electrons could be directly injected to both semiconductors, indicating the possibility of highly efficient spin injection into the CdSe and CdTe semiconductors.

  18. 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)

    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-Cu2S 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-Cu2S 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 H2 plasma and air heating, were also verified. (C.L.B.)

  19. Extracting Cu Diffusion Parameters in Polycrystalline CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Akis, Richard [Arizona State Univeristy; Brinkman, Daniel [Arizona State Univeristy; Sankin, Igor [First Solar; Fang, Tian [First Solar; Guo, Da [Arizona State Univeristy; Dragica, Vasileska [Arizona State Univeristy; Ringhofer, Christian [Arizona State University

    2014-06-13

    It is well known that Cu plays an important role in CdTe solar cell performance as a dopant. In this work, a finite-difference method is developed and used to simulate Cu diffusion in CdTe solar cells. In the simulations, which are done on a two-dimensional (2D) domain, the CdTe is assumed to be polycrystal-line, with the individual grains separated by grain boundaries. When used to fit experimental Cu concentration data, bulk and grain boundary diffusion coefficients and activation energies for CdTe can be extracted. In the past, diffusion coefficients have been typically obtained by fitting data to simple functional forms of limited validity. By doing full simulations, the simplifying assumptions used in those analytical models are avoided and diffusion parameters can thus be determined more accurately.

  20. 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.

  1. Stabilizing CdTe/CdS solar cells with Cu-containing contacts to p-CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Dobson, K.D.; Visoly-Fisher, I.; Hodes, G.; Cahen, D. [Weizmann Inst. of Science, Rehovoth (Israel)

    2001-10-02

    High efficiency CdTe/CdS thin-film solar cells require low resistance contacts to p-CdTe, which is frequently achieved by addition of Cu. Decreases in cell efficiency over time, however, have been associated with Cu from the contact. The question that is considered here is if Cu is really detrimental to cell performance? By performing a series of thermal stress tests the authors reach a far more optimistic conclusion than what has hitherto been assumed.f (orig.)

  2. Thermal fatigue damage of Cu-Cr-Zr alloys

    Science.gov (United States)

    Chatterjee, Arya; Mitra, R.; Chakraborty, A. K.; Rotti, C.; Ray, K. K.

    2013-11-01

    The primary aim of this investigation is to examine thermal fatigue damage (TFD) in Cu-Cr-Zr alloys used in High Heat Flux components of Tokamak and its subsystems. Thermal fatigue experiments have been carried out between 290 °C and 30 °C, which is analogous to the condition of service application on two Cu-Cr-Zr alloys having different aging treatments. The extents of TFD have been examined by standard measurements of electrical conductivity, lattice strain, residual stress and dynamic elastic modulus, supplemented by characterizations of microstructure and determination of hardness and tensile properties. The results lead to infer that the relative amounts of damage are different in the two alloys which are further dependent on their aging conditions; the reasons for the observed difference have been explained. The operative mechanisms of TFD are revealed to be as formation and subsequent coalescence of microvoids, and/or initiation and growth of microcracks.

  3. Grain refinement in CuCrZr by SPD processing

    Energy Technology Data Exchange (ETDEWEB)

    Kulczyk, Mariusz [Polish Academy of Sciences, Institute of High Pressure Physics (UNIPRESS), Warszawa (Poland); Zysk, Beata; Lewandowska, Malgorzata; Kurzydlowski, Krzysztof J. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Woloska 141, 02-507 Warsaw (Poland)

    2010-05-15

    CuCrZr alloys exhibit relatively high strength (due to precipitation hardening) and high thermal and electrical conductivity which make them attractive for variety of applications, e.g. as heat sinks and electrodes. In the present study, a CuCrZr alloy was subjected to severe plastic deformation (SPD) to increase its strength by grain refinement without modification of the chemical composition. A combination of the multi-pass equal channel angular pressing (ECAP) followed by cumulative hydrostatic extrusion (HE) was applied with a total true strain of 11.5. The microstructure of SPD samples was evaluated by transmission and scanning electron microscopy. The grain sizes were quantitatively described. The resulting mechanical properties were determined in tensile tests and via microhardness measurements. The results show that the applied SPD route, combining ECAP and HE, leads to high grain size refinement accompanied by high increase of strength. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  4. STUDY ON MORPHOLOGY OF CHROMIUM IN CHILLED Cu-0.14%-2.0%Cr ALLOYS

    Institute of Scientific and Technical Information of China (English)

    H.W.Yang; Z.K.Fan

    2004-01-01

    The morphology of chromium in chilled Cu-Cr alloys with 0.14%-2.0% Cr has been studied. The results showed that eutectic Cr phase takes a fibrous shape, and pre-eutectic Cr is dendritic in the studied chilled Cu-Cr alloy. During solute treatment of the eutectic and super-eutectic Cu-Cr alloys, only part of chromium particles dissolved in copper phase,some fiber and dendritic chromium still remained. Forging before solute treatment can reduce the size of primary Cr particles, which benefits the aging structure.

  5. Effects of Cu(II on the Adsorption Behaviors of Cr(III and Cr(VI onto Kaolin

    Directory of Open Access Journals (Sweden)

    Juanjuan Liu

    2016-01-01

    Full Text Available The adsorption of Cr(III or Cr(VI in the absence and presence of Cu(II onto kaolin was investigated under pH 2.0–7.0. Results indicated that the adsorption rate was not necessarily proportional to the adsorption capacity. The solutions’ pH values played a key role in kaolin zeta potential (ζ, especially the hydrolysis behavior and saturation index of heavy metal ions. In the presence of Cu(II, qmixCr(III reached the maximum adsorption capacity of 0.73 mg·g−1 at pH 6.0, while the maximum adsorption capacity for the mixed Cr(VI and Cu(II system (qmixCr(VI was observed at pH 2.0 (0.38 mg·g−1. Comparing the adsorption behaviors and mechanisms, we found that kaolin prefers to adsorb hydrolyzed products of Cr(III instead of Cr3+ ion, while adsorption sites of kaolin surface were occupied primarily by Cu(II through surface complexation, leading to Cu(II inhibited Cr(VI adsorption. Moreover, Cr(III and Cr(VI removal efficiency had a positive correlation with distribution coefficient Kd. Cr(III and Cr(VI removal efficiency had a positive correlation with distribution coefficient Kd and that of adsorption affinities of Cr(III or Cr(VI on kaolin was found to be Kd Cr(III Kd Cr(VI-Cu(II.

  6. Cu6Te3S. A Cu-filled Cr3Si-structure variant

    International Nuclear Information System (INIS)

    A solid state melting and annealing route was used to prepare Cu6Te3S, a copper telluride sulfide representing a filled variant of the Cr3Si structure type. The title compound exhibits a reversible phase transition at 404 K which was confirmed by thermal analysis, temperature dependent X-ray single crystal and powder diffractometry. Both polymorphs crystallize cubic in space groups P anti 43n and P213, respectively. X-ray photoelectron spectroscopy (XPS) was performed to evaluate the electronic structure of Cu6Te3S and to determine the oxidation state of Cu in the title compound.

  7. Thermodynamics and kinetics in liquid immiscible Cu-Cr-Si ternary system

    International Nuclear Information System (INIS)

    Research highlights: → We deal with the thermodynamics and kinetics in liquid immiscible Cu-Cr-Si alloys. → The phase equilibria in the Cu-Cr-Si system has been experimentally determined. → The phase equilibria in the Cu-Cr-Si system has been thermodynamically assessed. → The formation of top-bottom separated morphology of the Cu-Cr-Si alloys was analyzed. → The core-shell separated morphology of the Cu-Cr-Si alloys was analyzed. - Abstract: This work firstly focuses on the thermodynamic and kinetic studies of the liquid phase separation in the Cu-Cr-Si ternary system. On the thermodynamic aspect, four isothermal sections of the Cu-Cr-Si system at 900 deg. C, 1000 deg. C, 1100 deg. C and 1200 deg. C have been experimentally determined by X-ray diffraction (XRD) and electron probe microanalyzer (EPMA) on the equilibrated alloys, and the phase equilibria in the Cu-Cr-Si ternary system has been thermodynamically assessed by using the CALPHAD (Calculation of Phase Diagrams) technique on the basis of the presently obtained experimental results. The addition of Si can stabilize the metastable liquid phase separation in the Cu-Cr binary system, and increase its critical temperature. On the kinetic aspect, the formation of top-bottom and core-shell separated morphologies of the as-cast liquid immiscible Cu-Cr-Si alloys under various cooling rates have been detailedly analyzed.

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

    OpenAIRE

    Cinca Ionel Lupinca; Constantin Marta; Attila Szabo

    2012-01-01

    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 ...

  9. Preparation of CuCr alloys by thermit-reduction electromagnetic stirring

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The influences of the additive CaF2, different molds, mold pre-heating temperature, electromagnetic stirring, and alloying elements on CuCr have been investigated respectively during the preparation of CuCr alloys by thermit-reduction electromagnetic cation point of slags to improve the metal separating efficiency from slags; the crystal particles become thinner because of the high cooling velocity in the metal mold; while casting in the graphite mold, the casting properties of CuCr improve with the increase of pre-heating temperature; the compact alloys are prepared at 500℃; electromagnetic stirring can prevent the growth of dendrite crystal into refine crystal particles, as well as homogenize Cu and Cr to improve the CuCr properties; the optimal stirring time is 7 min;when the alloying elements Ni and Co are added to the reactants, elements Cu and Cr can distribute evenly but the crystal particles become thick.

  10. Luminescence Dynamics of Cr2+ in CdTe and Cd0.55Mn0.45Te

    Science.gov (United States)

    Bluiett, A.; Hommerich, U.; Seo, J. T.; Shah, R.; Trivedi, S. B.; Kutcher, S. W.; Chen, R. J.; Wang, C. C.; Zong, H.

    2001-04-01

    Cr^2+ in tetrahedrally coordinated CdTe and Cd_0.55Mn_0.45Te crystals are under investigation as potential host materials for tunable, mid-infrared (MIR) lasers. The small crystal field splitting of the free ion energy levels of Cr^2+ induces absorption (1900nm) and stokes shifted emission (2000nm-3000nm) bands in the MIR. Also, the relatively large ionic mass and tetrahedral environment of Cr^2+ in CdTe and Cd_0.55Mn_0.45Te have shown that the luminescence efficiency at room temperature is approximately 72100luminescence lifetime decreases rapidly, which suggest that the effects of nonradiative decay increases. The decay dynamics of Cr^2+ in CdTe and Cd_0.55Mn_0.45Te will be described with the model of Struck and Fonger for the non-radiative decay rate.

  11. Structural study of Cu-Cr mechanical alloying powders; Estudio estrucgrual de polvos Cu-Cr aleados mecanicamente

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, C.; Marin, J.; Ordonez, S.; Celentano, D.; Castro, F.; Martinez, V.

    2006-07-01

    The changes of grain size, micro strain, stacking fault probability, stacking fault energy and dislocations density on powder mixtures of copper with 1 and 3 weights after higher energy mechanical milling. The X-ray diffraction profile was analysed by Williamson-Hall (W-H) method. Grain size decreased with the increase of milling time, until values of 106 and 59 nm for 1 and 3 weight % Cr, respectively. As well micro strain increased with milling time. Stacking fault probability increased in function of milling time to value between 1x10''-3 -8x10''-3 for Cu-1 weighty Cr and 3x10''-3 -8x10''-3 for Cu-3 weight % Cr. The stacking fault energy decreased with milling time and amount of chromium. Finally, the dislocations density is between 1x10''14 -1x10''15 m/m''3. (Author) 29 refs.

  12. 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.

  13. 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.

  14. Traces of Z2 vortices in CuCrO2, AgCrO2, and PdCrO2

    International Nuclear Information System (INIS)

    The spin-spin relaxation of the two-dimensional triangular lattice antiferromagnets CuCrO2, AgCrO2, and PdCrO2 is investigated by electron spin resonance spectroscopy. The data proof excellent agreement with very recent predictions for the Z2-vortex ordering scenario in triangular Heisenberg antiferromagnets derived by Okubo and Kawamura. (author)

  15. Cu-doped CdS and its application in CdTe thin film solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Yi [School of Automation, Wuhan University of Technology, Wuhan, Hubei 430070 (China); College of Electronic and Information Engineering, Hankou University, Wuhan, Hubei 430212 (China); Yang, Jun; Yang, Ruilong; Shen, Kai; Wang, Dezhao [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang, Deliang, E-mail: eedewang@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2016-01-15

    Cu is widely used in the back contact formation of CdTe thin film solar cells. However, Cu is easily to diffuse from the back contact into the CdTe absorber layer and even to the cell junction interface CdS/CdTe. This phenomenon is generally believed to be the main factor affecting the CdTe solar cell stability. In this study Cu was intentionally doped in CdS thin film to study its effect on the microstructural, optical and electrical properties of the CdS material. Upon Cu doping, the V{sub Cd{sup −}} and the surface-state-related photoluminescence emissions were dramatically decreased/quenched. The presence of Cu atom hindered the recrystallization/coalescence of the nano-sized grains in the as-deposited CdS film during the air and the CdCl{sub 2} annealing. CdTe thin film solar cell fabricated with Cu-doped CdS window layers demonstrated much decreased fill factor, which was induced by the increased space-charge recombination near the p-n junction and the worsened junction crystalline quality. Temperature dependent current-voltage curve measurement indicated that the doped Cu in the CdS window layer was not stable at both room and higher temperatures.

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

    International Nuclear Information System (INIS)

    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 JQ 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

  17. Dechromisation of Cu-Cr alloy in acid solutions containing Cl-

    Institute of Scientific and Technical Information of China (English)

    许涛; 陈玲; 谌岩; 于升学; 刘彬; 刘建华

    2004-01-01

    The phenomenon, characteristics and influence factors of dechromisation of a Cu-Cr alloy in acid solutions containing Cl- were studied by means of metallographic observation, SEM/EDX, TEM and XRD. The mechanism of dechromisation of Cu-Cr alloy was discussed. The results show that dechromisation of the Cu-Cr alloy occurs at a certain temperature in solutions with H+ and Cl- simultaneously. The corrosion starts initially at the interfaces between Cu phase and Cr phase, then develops gradually into the centers of Cr phase. It is also revealed that dechromisation rates of the Cu-Cr alloy increase with increasing concentration of H+ or Cl-, and temperature of the solutions.

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

    International Nuclear Information System (INIS)

    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 Cu94Cr6-4% SiC. → Microwave suscepting SiC particles played a pivotal role in good densification retaining matrix grains 99Cr1, Cu94Cr6, Cu99Cr1-4 wt.% SiC and Cu94Cr6-4 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 Cu94Cr6-4 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.

  19. Structural investigation of vacuum sintered Cu-Cr and Cu-Cr-4% SiC nanocomposites prepared by mechanical alloying

    International Nuclear Information System (INIS)

    Highlights: → Solid solubility of Cr in Cu extended up to 1 at.% in presence of SiC nanoparticles. → Change in lattice parameter is the only evidence for solid solubility extension. → Nanosize SiC particles refined the crystallite size of Cu matrix up to 16-17 nm. → Vacuum sintered specimens showed high hardness (1.8 GPa) and good conductivity (48% of IACS). → SiC particles not only hinder grain growth but also control its distribution. - Abstract: Attempts have been made to synthesize Cu99Cr1, Cu94Cr6, Cu99Cr1-4% SiC and Cu94Cr6-4% SiC (∼30 nm) nanocomposites for thermo-electric applications. The blend compositions were ball-milled for 50 h in a stainless steel grinding media. The microstructural features were characterized by X-ray diffraction (XRD), Nano zeta sizer, Fourier transforms infrared radiation, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Analysis of crystallite size, lattice microstrain and lattice parameter of Cu revealed that the dissolution of Cr increased up to 1 at.% in presence of nanosize SiC particles during milling. The compact specimens were subjected to vacuum sintering (900 deg. C and 1000 deg. C for 1 h), and the results were compared with that of microwave sintered samples. The mechanical properties like Vickers hardness and electrical conductivity of the sintered specimens were also investigated.

  20. Cu-doped CdS and its application in CdTe thin film solar cell

    International Nuclear Information System (INIS)

    Cu is widely used in the back contact formation of CdTe thin film solar cells. However, Cu is easily to diffuse from the back contact into the CdTe absorber layer and even to the cell junction interface CdS/CdTe. This phenomenon is generally believed to be the main factor affecting the CdTe solar cell stability. In this study Cu was intentionally doped in CdS thin film to study its effect on the microstructural, optical and electrical properties of the CdS material. Upon Cu doping, the VCd− and the surface-state-related photoluminescence emissions were dramatically decreased/quenched. The presence of Cu atom hindered the recrystallization/coalescence of the nano-sized grains in the as-deposited CdS film during the air and the CdCl2 annealing. CdTe thin film solar cell fabricated with Cu-doped CdS window layers demonstrated much decreased fill factor, which was induced by the increased space-charge recombination near the p-n junction and the worsened junction crystalline quality. Temperature dependent current-voltage curve measurement indicated that the doped Cu in the CdS window layer was not stable at both room and higher temperatures

  1. Cu-doped CdS and its application in CdTe thin film solar cell

    Directory of Open Access Journals (Sweden)

    Yi Deng

    2016-01-01

    Full Text Available Cu is widely used in the back contact formation of CdTe thin film solar cells. However, Cu is easily to diffuse from the back contact into the CdTe absorber layer and even to the cell junction interface CdS/CdTe. This phenomenon is generally believed to be the main factor affecting the CdTe solar cell stability. In this study Cu was intentionally doped in CdS thin film to study its effect on the microstructural, optical and electrical properties of the CdS material. Upon Cu doping, the VCd− and the surface-state-related photoluminescence emissions were dramatically decreased/quenched. The presence of Cu atom hindered the recrystallization/coalescence of the nano-sized grains in the as-deposited CdS film during the air and the CdCl2 annealing. CdTe thin film solar cell fabricated with Cu-doped CdS window layers demonstrated much decreased fill factor, which was induced by the increased space-charge recombination near the p-n junction and the worsened junction crystalline quality. Temperature dependent current-voltage curve measurement indicated that the doped Cu in the CdS window layer was not stable at both room and higher temperatures.

  2. Experiment study on Be|Ti/Cu|CuCrZr joints by hot isostatic pressing bonding

    International Nuclear Information System (INIS)

    Performances of Be/Cu joints fabricated by hot isostatic pressing (HIP) bonding were studied by means of various test Methods, such as shearing test, scanning electron microscopy(SEM) observation, energy dispersion spectrometer(EDS) and X-ray Diffraction(XRD) analysis, when Ti (PVD-coated on Be)/Cu (PVD-coated on CuCrZr) interlayers were used. This study considered several diffusion surface treatments (such as chemical etching, polishing, etc.) for minimizing or eliminating the effects of the oxide film on beryllium to promote good diffusion bond between these materials. Experiments indicated that the joints HIPed at 580 degree C/145 MPa/2 h showed high shearing strength (up to 123 MPa) at room temperature and no defect such as cracks was observed at the bonding interface dut to the role of the etching with a dilute acid solution to remove native oxide films on beryllium surface prior to titanium coating. The strength moderately decreased when the diffusion holding time increased from 2 h to 4 h. The thin titanium diffusion barrier (∼10μm) which was coated on the beryllium surface have prevented the reaction between Be and Cu, but CuTi phase was formed at Ti/Cu interface. It is considered the phase limited the bonding strength to higher level. (authors)

  3. Oxidation-Resistant of Cr/Cu/Al/Cr Thin Film Electrodes%Cr/Cu/Al/Cr薄膜电极的防氧化性能

    Institute of Scientific and Technical Information of China (English)

    翁卫祥; 于光龙; 贾贞; 李昱; 郭太良

    2011-01-01

    Novel Cr/Cu/Al/Cr thin film electrodes were prepared by DC magnetron sputtering and wet etching technology, in which Al thin film was used as the protective layer for Cu layer.The change of the crystal structure, surface morphology and electric resistivity of the thin films and electrodes before and after heat treatment were studied.The Al layer played a key role as an oxygen diffusion barrier layer, for its protection, the Cr/Cu/Al/Cr thin film still had good thermal stability when the heat treatment was below 600 ℃.Meanwhile, the oxidation diffusion from the lateral edge of the electrodes as the temperature increased caused the decrease of the conduction of the electrodes.The electric resistivity was increasing obviously after 500 ℃ heat treatment, and the oxidation region was expanded from the edge to the surface of the electrode.Nonetheless, the thin film electrode fulfilled the requirements of field emission device for its stable resistance when post annealing temperature was 430 ℃, which was 7.2× 10-8 Ω · m.Based on the new electrode, the FED device was fabricated for verifying its oxidation resistance.%采用Al作为Cu导电层的主要防氧化保护层,在普通浮法玻璃上利用磁控溅射和湿法刻蚀技术制备Cr/Cu/Al/Cr复合薄膜及其电极,研究不同的热处理温度对复合薄膜及其电极的结构、表面形貌和导电性能的影响.由于有Al层作为保护层,在热处理过程中,Al先与穿过Cr保护层的氧进行反应,从而可以更有效地保护Cu膜层在较高的温度下不被氧化,所制备的薄膜在经过600℃的热处理之后仍然具有较好的导电性能.而对于Cr/Cu/Al/Cr电极,侧面裸露的金属层在热处理过程中的氧化是其导电性能逐渐下降的主要原因,退火温度超过500℃之后,电极侧面裸露部分的氧化范围不断往电极的中间扩散,导致了薄膜电极导电性能显著恶化.虽然如此,Cr/Cu/Al/Cr薄膜电极在430℃附近仍然具有较好

  4. Determination of Cr and Cd concentration adsorbed by chicken feathers

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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)

  6. Study on CuCrAl and CuCrZr Oxides as Catalysts for Low-Temperature Slurry Phase Methanol Synthesis%CuCrAl和CuCrZr低温液相合成甲醇催化剂的研究

    Institute of Scientific and Technical Information of China (English)

    郝立庆; 单绍纯; 田瑞芬; 丁延伟; 陈根发; 庄叔贤

    2003-01-01

    用络合共沉淀法制备了CuCrAl和CuCrZr复合氧化物液相合成甲醇催化剂,其比表面分别达到119和116 m2/g. 在5.0~5.5 Mpa和383 K条件下,分别用间歇式和流动式反应釜考察了催化剂的活性和稳定性. 结果表明: CuCrAl和CuCrZr的活性均明显高于CuCr; CuCrAl的活性略高于CuCrZr,但甲酸甲酯(MF)的选择性明显低于CuCrZr; 两者在12 h内未见活性明显下降. 甲醇钠在反应过程中部分转化为甲酸钠和NaOH. CuCrAl和CuCrZr有较高的氢解活性可抑制甲醇钠与MF生成甲酸钠,从而有较低的甲酸钠浓度. 但是,Al2O3和ZrO2的酸性有利于甲醇脱水,引起甲醇钠水解生成NaOH. 溶剂对CuCr基催化剂的活性和选择性有明显影响. 对反应机理进行了讨论.

  7. Selective Detection of NO2 Using Cr-Doped CuO Nanorods

    Directory of Open Access Journals (Sweden)

    Kang-Min Kim

    2012-06-01

    Full Text Available CuO nanosheets, Cr-doped CuO nanosheets, and Cr-doped CuO nanorods were prepared by heating a slurry containing Cu-hydroxide/Cr-hydroxide. Their responses to 100 ppm NO2, C2H5OH, NH3, trimethylamine, C3H8, and CO were measured. For 2.2 at% Cr-doped CuO nanorods, the response (Ra/Rg, Ra: resistance in air, Rg: resistance in gas to 100 ppm NO2 was 134.2 at 250 °C, which was significantly higher than that of pure CuO nano-sheets (Ra/Rg = 7.5 and 0.76 at% Cr-doped CuO nanosheets (Ra/Rg = 19.9. In addition, the sensitivity for NO2 was also markedly enhanced by Cr doping. Highly sensitive and selective detection of NO2 in 2.2 at% Cr-doped CuO nanorods is explained in relation to Cr-doping induced changes in donor density, morphology, and catalytic effects.

  8. Characterization of transparent conductive delafossite-CuCr1−xO2 films

    International Nuclear Information System (INIS)

    In this study, the CuCr1−xO2 films with x = 0.00–0.25 were prepared on a quartz substrate by sol–gel processing. The films were first deposited onto a quartz substrate by spin-coating. The specimens were annealed at 500 °C in air for 1 h and post-annealed in N2 at 700 °C for 2 h. As the films were post-annealed in N2, a pure delafossite-CuCrO2 phase appeared in the CuCr1−xO2 films below x = 0.20. However, an additional CuO phase appeared at x = 0.25. The pure delafossite-CuCrO2 phase can exist within x ≤ 0.20 in CuCr1−xO2 films. The binding energies of Cu-2p3/2 and Cr-2p3/2 in the CuCr1−xO2 films with the pure delafossite-CuCrO2 phase were 932.1 ± 0.2 eV and 576.0 ± 0.2 eV, respectively. The surface exhibited elongated grain features when the pure delafossite-CuCrO2 phase was present in the CuCr1−xO2 films. The maximum transmittance of the CuCr1−xO2 films with the pure delafossite-CuCrO2 phase was approximately 80%, which moved toward the visible region with the increasing x-value. The film absorption edges were observed at 400 nm, which were sharper with the increasing x-value. The optical bandgaps of CuCr1−xO2 films with the pure delafossite-CuCrO2 phase were approximately 3.0 eV. The electrical conductivity of CuCr1−xO2 films with the pure delafossite-CuCrO2 phase was 1.1 × 10−3 S cm−1 (x = 0.00), and increased to 0.16 S cm−1 (x = 0.20). The corresponding carrier concentration of CuCr1−xO2 films with the pure delafossite-CuCrO2 phase was 2.8 × 1014 cm−3 (x = 0.00), and markedly increased to 1.8 × 1016 cm−3 (x = 0.20). The Cr-deficient condition in delafossite-CuCrO2 films enhances film electrical conductivity and carrier concentration, but retains the film's high-visible transparency.

  9. The Effect of Diffusion Barrier and Bombardment on Adhesive Strength of CuCr Alloy Films

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-feng; SONG Zhong-xiao; XU Ke-wei; WANG Yuan

    2004-01-01

    A novel co-sputtering method that combined magnetron sputtering (MS) with ion beam sputtering (IBS) was used to fabricate CuCr alloy films without breaking vacuum after depositing diffusion barrier with IBS. Different bombardment energies were used to improve the comprehensive properties of Cu alloy film. The results indicated that the effects of diffusion barriers and bombardment energy on adhesive strength could be evaluated by a rolling contact fatigue adhesion test. Diffusion barrier can enhance the adhesive strength, and the adhesion of CuCr/CrN was higher than that of CuCr/TiN. When bombarding energy was higher, the adhesive strength of CuCr/TiN films was higher due to the broader transition zone.

  10. Aging Precipitation Characterics of Lead Frame Cu-Cr-Zr-Mg Alloy

    Institute of Scientific and Technical Information of China (English)

    DONG Qi-ming; SU Jua -hua; LIU Ping; LI He-jun; KANG Bu-xi

    2004-01-01

    This paper presents the effects of aging processes on the properties and microstructure of Cu-0.3Cr-0.15Zr-0.05Mg lead frame alloy. Optimal conditions for good hardening and electrical conductivity can be obtained by solution treating at 920℃ for lh and aging at 470℃ for 4h and at 550℃ for lh. The hardness and electrical conductivity can reach 108HV, 73%IACS and 106HV, 76%IACS, respectively. Aging precipitation was dealt with by transmission electronic microscope (TEM). At 470℃ aging for 4h the fine precipitation of an ordered compound CrCu2(Zr, Mg) is found in matrix as well as fine Cr and Cu4Zr. Aging at 550℃ for lh some precipitates are still coherent with matrix. The CrCu2(Zr, Mg) completely dissolves into Cr and Cu4Zr.

  11. Liquid phase separation of Cu-Cr alloys during rapid cooling

    Institute of Scientific and Technical Information of China (English)

    SUN Zhan-bo; WANG You-hong; GUO Juan

    2006-01-01

    The ribbons of Cu-Cr alloys with high Cr content (15%-35%, mass fraction) were prepared by rapid solidification. The microstructures of solidified samples were analyzed by scanning electron microscopy and transmission electron microscopy. The results reveal that a representative liquid phase separation microstructures are observed in Cu75Cr25 ribbons solidified at a cooling rate of about 104 K/s. The liquid phase separation is not restrained when the cooling rate is enhanced to about 107 K/s. However, the size of Cr particles solidified from Cr-rich liquid or Cr-rich regions in alloy melts could be refined by increasing the cooling rates. The size of Cr particles increases with increasing Cr contents when the ribbons contain 15% to 35%Cr.

  12. Cu and Cd Adsorption on Carbon Aerogel and Xerogel

    Directory of Open Access Journals (Sweden)

    Cotet L. C.

    2013-04-01

    Full Text Available Carbon aerogel (CA and xerogel (CX were proposed as new carbon adsorbent materials for Cu and Cd ions from contaminated water (synthetic water samples. These materials were prepared by a sol-gel process that involves a polycondensation of resorcinol and formaldehyde in Na2CO3 catalysis, followed by a drying step, either in supercritical conditions of CO2 to aerogel obtaining or in normal conditions to xerogel obtaining, and a pyrolytic step. Nitrogen adsorption, AFM, SEM, TEM and XRD were used for morpho-structural adsorbent investigation. Cu and Cd ions adsorption experiments were carried out in batch conditions under magnetic stirring. Adsorbent quantity and grain size influence over the adsorption efficiency were considered. Adsorption results expressed as adsorption capacities showed that prepared CA is a better adsorbent than CX. Adsorption capacities up to 14.2 mg g-1 and 8.5 mg g-1 were obtained for Cd2+ and Cu2+ adsorption on CA, respectively.

  13. Physical properties of electron beam evaporated CdTe and CdTe:Cu thin films

    International Nuclear Information System (INIS)

    In this paper, we report on physical properties of pure and Cu doped cadmium telluride (CdTe) films deposited onto corning 7059 microscopic glass substrates by electron beam evaporation technique. X-ray diffraction study showed that all the deposited films belong to amorphous nature. The average transmittance of the films is varied between 77% and 90%. The optical energy band gap of pure CdTe film is 1.57 eV and it decreased to 1.47 eV upon 4 wt. % of Cu addition, which may be due to the extension of localized states in the band structure. The refractive index of the films was calculated using Swanepoel method. It was observed that the dispersion data obeyed the single oscillator of the Wemple-Didomenico model, from which the dispersion energy (Ed) parameters, dielectric constants, plasma frequency, and oscillator energy (Eo) of CdTe and CdTe:Cu films were calculated and discussed in detail with the light of possible mechanisms underlying the phenomena. The variation in intensity of photoluminescence band edge emission peak observed at 820 nm with Cu dopant is due to the change in surface state density. The observed trigonal lattice of Te peaks in the micro-Raman spectra confirms the p-type conductive nature of films, which was further corroborated by the Hall effect measurement. The lowest resistivity of 6.61 × 104 Ω cm was obtained for the CdTe:Cu (3 wt. %) film

  14. Room-temperature ferromagnetism in Mn-doped CuCrO2 nanopowders

    Directory of Open Access Journals (Sweden)

    DENG Linyan

    2015-08-01

    Full Text Available (Cu1-xMnxCrO2 (0≤x≤6 at% and Cu(Cr1-yMnyO2 (0≤y≤6 at% nanopowders were prepared by combining solid-state reaction and ball milling.It is found that all the samples have a pure 3R-CuCrO2 delafossite structure.The lattice expansion supports the Mn entrance into the Cu and Cr sublattices,respectively,in (Cu1-xMnxCrO2 and Cu(Cr1-yMnyO2,which is further proved by X-ray photoelectron spectroscopy to some degree.Room-temperature ferromagnetism is achieved in B-site Mn-doped samples,originating from the hole-mediated Cr3+-Mn3+ double-exchange interaction.The saturation magnetization of this CuMO2 delafossite (M=Cr,Mn is about an order of magnitude higher than literature values,and gradually decreases with the Mn addition due to the combined influence of the number of the M-M pairs,the M-M distances and the hole density.

  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 8485905 CR3 (CD11b, CD18): a phagocyte and NK cell membrane receptor with multipleligand specificitie...) (.html) (.csml) Show CR3 (CD11b, CD18): a phagocyte and NK cell membrane receptor with multipleligand specificitie...d NK cell membrane receptor with multipleligand specificities and functions. Authors Ross GD, Vetvicka V. Pu

  16. Colloidal CdSe/Cu3P/CdSe nanocrystal heterostructures and their evolution upon thermal annealing.

    Science.gov (United States)

    De Trizio, Luca; De Donato, Francesco; Casu, Alberto; Genovese, Alessandro; Falqui, Andrea; Povia, Mauro; Manna, Liberato

    2013-05-28

    We report the synthesis of colloidal CdSe/Cu(3)P/CdSe nanocrystal heterostructures grown from hexagonal Cu(3)P platelets as templates. One type of heterostructure was a sort of "coral", formed by vertical pillars of CdSe grown preferentially on both basal facets of a Cu(3)P platelet and at its edges. Another type of heterostructure had a "sandwich" type of architecture, formed by two thick, epitaxial CdSe layers encasing the original Cu(3)P platelet. When the sandwiches were annealed under vacuum up to 450 °C, sublimation of P and Cd species with concomitant interdiffusion of Cu and Se species was observed by in situ HR- and EFTEM analyses. These processes transformed the starting sandwiches into Cu2Se nanoplatelets. Under the same conditions, both the pristine (uncoated) Cu(3)P platelets and a control sample made of isolated CdSe nanocrystals were stable. Therefore, the thermal instability of the sandwiches under vacuum might be explained by the diffusion of Cu species from Cu(3)P cores into CdSe domains, which triggered sublimation of Cd, as well as out-diffusion of P species and their partial sublimation, together with the overall transformation of the sandwiches into Cu(2)Se nanocrystals. A similar fate was followed by the coral-like structures. These CdSe/Cu(3)P/CdSe nanocrystals are therefore an example of a nanostructure that is thermally unstable, despite its separate components showing to be stable under the same conditions. PMID:23557168

  17. EXAFS in La2Cu1-xMxO4 (M = Cd,Ga)

    International Nuclear Information System (INIS)

    This paper reports on the local structure in La2Cu0.9Ga0.1O4 and La2cu0.9Cd0.1 that has been studied by Extended X-Ray Absorption Fine Structure (EXAFS) at the Cu, Ga and Cd K-edges. The results indicate that the Ga atoms, effective in suppressing Tc in La2CuO4 derived superconductors, induce structural distortions and seem not to be properly substituted at Cu sites. On the other hand, the Cd atoms, having a weak effect on Tc, substitute for Cu with small changes in the structure

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

  20. Chemical bath deposition of CdS thin films doped with Zn and Cu

    Indian Academy of Sciences (India)

    A I Oliva; J E Corona; R Patiño; A I Oliva-Avilés

    2014-04-01

    Zn- and Cu-doped CdS thin films were deposited onto glass substrates by the chemical bath technique. ZnCl2 and CuCl2 were incorporated as dopant agents into the conventional CdS chemical bath in order to promote the CdS doping process. The effect of the deposition time and the doping concentration on the physical properties of CdS films were investigated. The morphology, thickness, bandgap energy, crystalline structure and elemental composition of Zn- and Cu-doped CdS films were investigated and compared to the undoped CdS films properties. Both Zn- and Cu-doped CdS films presented a cubic crystalline structure with (1 1 1) as the preferential orientation. Lower values of the bandgap energy were observed for the doped CdS films as compared to those of the undoped CdS films. Zn-doped CdS films presented higher thickness and roughness values than those of Cu-doped CdS films. From the photoluminescence results, it is suggested that the inclusion of Zn and Cu into CdS crystalline structure promotes the formation of acceptor levels above the CdS valence band, resulting in lower bandgap energy values for the doped CdS films.

  1. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Lina SUN; Xiao-e YANG; Wen-qing WANG; Li MA; Su CHEN

    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 con- tamination 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.

  3. PENINGKATAN KUALITAS FILM TIPIS CdTe SEBAGAI ABSORBER SEL SURYA DENGAN MENGGUNAKAN DOPING TEMBAGA (Cu)

    OpenAIRE

    P. Marwoto; N.M. Darmaputra; Sugianto -; Othaman, Z.; E. Wibowo; S.Y. Astuti

    2012-01-01

    Film tipis CdTe dengan doping tembaga (Cu) berkonsenterasi 2% telah berhasil ditumbuhkan di atas substrat Indium Tin Oxide (ITO) dengan metode dc magnetron sputtering. Penelitian ini dilakukan untuk mengetahui pengaruh doping Cu(2%) terhadap struktur morfologi, struktur kristal, fotoluminisensi dan resistivitas listrik film CdTe. Citra morfologi Scanning Electron Microscopy (SEM) dan hasil analisis struktur dengan X-Ray Diffraction (XRD) menunjukkan bahwa film CdTe:Cu(2%) mempunyai citra perm...

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

    Institute of Scientific and Technical Information of China (English)

    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 CuCrO2.Intrinsic defects,some typical acceptortype,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,Vcu,Oi,and OCu are the relevant intrinsic defects in CuCrO2; among these intrinsic defects,VCu is the most efficient acceptor in CuCrO2.It is found that all the donor-type extrinsic defects have difficulty in inducing n-conductivity in CuCrO2 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 CuCrO2.Our calculation results are expected to be a guide for preparing promising n-type and p-type materials in CuCrO2.

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

    International Nuclear Information System (INIS)

    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

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

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Jensen, Pernille Erland; Hansen, Henrik K.; Ribeiro, Alexandra B.; Allard, Bert

    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...

  7. 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.

  8. Electrical conductivity and mechanical properties of Cu-0.7wt% Cr and Cu-1.0wt% Cr alloys processed by severe plastic deformation

    Science.gov (United States)

    Kommel, L.; Pokatilov, A.

    2014-08-01

    As-cast Cu-0.7wt% Cr and Cu-1.0wt% Cr alloys were subjected to equal-channel angular pressing (ECAP), hard cyclic viscoplastic (HCV) deformation and post deformation heat treatment for receiving an ultrafine grained material with a combination of high strength, good wear resistance and high electric conductivity. Samples from Cu-0.7wt% Cr alloy were processed up to six passes and Cu-1wt% Cr alloy samples were processed up to four passes of ECAP via Bc route. HCV deformation of samples was conducted by frequency of 0.5 Hz for 20 cycles at tension-compression strain amplitudes of +/-0.05%, +/-0.1%, +/-0.5%, +/-1% and +/-1.5%, respectively. During HCV deformation, as-cast Cu-0./wt% Cr alloy show fully viscoelastic behavior at strain/stress amplitude of +/-0.05% while ECAP processed material show the same behavior at strain amplitude of +/-0.1%. The Young modulus was increased from ~120 GPa up to ~150 GPa. The results illustrated that specific volume wear decrease with increasing of hardness but the measured coefficient of friction (COF ~ 0.6) was approximately the same for all samples at the end of wear testing. The hardness after ECAP for 6 passes by Bc route was 192HV0.1 and electric conduction 74.16% IACS, respectively. By this the as-cast Cu-0./wt% Cr alloy (heat treated at 1000 °C for 2h) has microhardness ~70HV0.1 and electrical conductivity of ~40% IACS. During aging at the temperatures in the interval of 250-550 °C for 1h the hardness and electrical conductivity were stabilized to mean values of 120+/-5HV0.1 and to 93.4+/-0.3% IACS, respectively. The hardness and electric conductivity took decrease by temperature increase over ~550 °C, respectively. The results of present experimental investigation show that UFG Cu- 0.7wt% Cr alloy with compare to Cu-1.0% Cr alloy is a highly electrical conductive and high temperature wear resistant material for using in electrical industry.

  9. Structural and magnetic properties of Cu-Ni-Cr spinel oxides

    International Nuclear Information System (INIS)

    The compounds CuCr2O4 and NiCr2O4 crystallize at room temperature in a tetragonal distorted spinel structure, s.g. I41/amd, with axes ratio c/a1, respectively. The distortion is caused by the Jahn-Teller ions Cu2+ and Ni2+ which flatten or elongate their surrounding oxygen tetrahedron. CuCr2O4 and NiCr2O4 form a complete solid solution series Cu1-x Ni x Cr2O4 where for 0.8252O4) and 310 K (NiCr2O4). The phase Cu0.15Ni0.85Cr2O4 undergoes a second crystallographic transition to orthorhombic symmetry, space group Fddd, at T=300 K. The neutron diffraction experiments as well as SQUID measurements reveal magnetic ordering of the ions between 150 and 50 K which partially occurs as a two-step mechanism

  10. Cu-Zn powders as potential Cr(VI) adsorbents for drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Kaprara, E.; Seridou, P.; Tsiamili, V.; Mitrakas, M. [Analytical Chemistry Laboratory, Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Vourlias, G.; Tsiaoussis, I.; Kaimakamis, G.; Pavlidou, E. [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Andritsos, N. [Department of Mechanical Engineering, University of Thessaly, 38334 Volos (Greece); Simeonidis, K., E-mail: ksime@physics.auth.gr [Department of Mechanical Engineering, University of Thessaly, 38334 Volos (Greece)

    2013-11-15

    Highlights: • Preparation of CuZn powders by ball-milling and mild annealing. • Cr(VI) removal efficiency is maximized near the equiatomic alloy composition. • RSSCT on commercial CuZn granules indicates the potential for application. • Side-effects include Cu and Zn leaching during the process. -- Abstract: This work examines the possibility of applying CuZn alloys as a reducing medium for the efficient removal of hexavalent chromium from drinking water. In an effort to develop a route for producing powders of CuZn alloys under mild conditions and investigate the optimum composition for such application, a series of alloys in the form of powders were prepared, by a sequence of Cu and Zn ball-milling and low temperature annealing. Batch Cr(VI) removal tests, performed to evaluate and compare the efficiency of the products under typical natural water parameters (pH 7 and natural-like water), indicated that the best performing material have a composition around 50 wt% Cu. The dominant reduction mechanisms are both the corrosion of the alloy surface and the electron transfer to the solution. The behavior of granulated CuZn media was tested in rapid-scale column tests using the commercial KDF which verified the high potential of CuZn alloys in Cr(VI) removal. Nevertheless, Cu and Zn leaching problems should be also considered.

  11. Compound pollution of Cd, Pb, Cu, Zn, and As on lowland rice

    Institute of Scientific and Technical Information of China (English)

    WUYanyu; WANGXin

    1999-01-01

    Cd, Pb, Cu, Zn, and As are typical pollutants originated from Pb-Zn mine, smelting waste water discharge/irrigation and gas emission,and they were distributed widely in China. We studied the compound pollution of Cd, Pb,Cu, Zn, and As on rice.

  12. Functional classification of memory CD8(+) T cells by CX3CR1 expression.

    Science.gov (United States)

    Böttcher, Jan P; Beyer, Marc; Meissner, Felix; Abdullah, Zeinab; Sander, Jil; Höchst, Bastian; Eickhoff, Sarah; Rieckmann, Jan C; Russo, Caroline; Bauer, Tanja; Flecken, Tobias; Giesen, Dominik; Engel, Daniel; Jung, Steffen; Busch, Dirk H; Protzer, Ulrike; Thimme, Robert; Mann, Matthias; Kurts, Christian; Schultze, Joachim L; Kastenmüller, Wolfgang; Knolle, Percy A

    2015-01-01

    Localization of memory CD8(+) T cells to lymphoid or peripheral tissues is believed to correlate with proliferative capacity or effector function. Here we demonstrate that the fractalkine-receptor/CX3CR1 distinguishes memory CD8(+) T cells with cytotoxic effector function from those with proliferative capacity, independent of tissue-homing properties. CX3CR1-based transcriptome and proteome-profiling defines a core signature of memory CD8(+) T cells with effector function. We find CD62L(hi)CX3CR1(+) memory T cells that reside within lymph nodes. This population shows distinct migration patterns and positioning in proximity to pathogen entry sites. Virus-specific CX3CR1(+) memory CD8(+) T cells are scarce during chronic infection in humans and mice but increase when infection is controlled spontaneously or by therapeutic intervention. This CX3CR1-based functional classification will help to resolve the principles of protective CD8(+) T-cell memory. PMID:26404698

  13. Cu{sub 2}S as ohmic back contact for CdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Türck, Johannes; Siol, Sebastian; Mayer, Thomas; Klein, Andreas; Jaegermann, Wolfram, E-mail: jaegermann@surface.tu-darmstadt.de

    2015-05-01

    We prepared a back contact for CdTe solar cells with Cu{sub 2}S as primary contact. Cu{sub 2}S was evaporated on CdCl{sub 2} treated CdTe solar cells in superstrate configuration. The CdTe and CdS layers were deposited by Closed Space Sublimation. Direct interface studies with X-ray photoelectron spectroscopy have revealed a strongly reactive interface between CdTe and Cu{sub 2}S. A valence band offset of 0.4-0.6 eV has been determined. The performance of solar cells with Cu{sub 2}S back contacts was studied in comparison to cells with an Au contact that deposited onto a CdCl{sub 2}-treated CdTe surface that was chemically etched using a nitric-phosphoric etch. The solar cells were analyzed by current-voltage curves and external quantum efficiency measurements. After several post deposition annealing steps, 13% efficiency was reached with the Cu{sub 2}S back contact, which was significantly higher than the ones obtained for the NP-etched back contacts. - Highlights: • A new back contact for CdTe solar out of Cu{sub 2}S has been tested. • With a direct interface experiment the valence band offset was determined. • Post deposition heat treatment has been carried out for the solar cells. • 13% efficiency has been reached with the Cu{sub 2}S back contact.

  14. Cu2S as ohmic back contact for CdTe solar cells

    International Nuclear Information System (INIS)

    We prepared a back contact for CdTe solar cells with Cu2S as primary contact. Cu2S was evaporated on CdCl2 treated CdTe solar cells in superstrate configuration. The CdTe and CdS layers were deposited by Closed Space Sublimation. Direct interface studies with X-ray photoelectron spectroscopy have revealed a strongly reactive interface between CdTe and Cu2S. A valence band offset of 0.4-0.6 eV has been determined. The performance of solar cells with Cu2S back contacts was studied in comparison to cells with an Au contact that deposited onto a CdCl2-treated CdTe surface that was chemically etched using a nitric-phosphoric etch. The solar cells were analyzed by current-voltage curves and external quantum efficiency measurements. After several post deposition annealing steps, 13% efficiency was reached with the Cu2S back contact, which was significantly higher than the ones obtained for the NP-etched back contacts. - Highlights: • A new back contact for CdTe solar out of Cu2S has been tested. • With a direct interface experiment the valence band offset was determined. • Post deposition heat treatment has been carried out for the solar cells. • 13% efficiency has been reached with the Cu2S back contact

  15. Substitution effect on the two-dimensional triangular-lattice system CuCrS2

    International Nuclear Information System (INIS)

    We have studied the magnetic susceptibility and specific heat of polycrystalline CuCr1-xVxS2, the mother compound of which, CuCrS2, has a nearly two-dimensional structure in which the triangular-lattice CrS2 layer and the Cu-ion layer are stacked alternately. The temperature dependence of the magnetic susceptibility revealed that only the Cr ions have local magnetic moment, and the V ions are nonmagnetic. CuCrS2 shows a long-range antiferromagnetic ordering at TN = 39 K, which is found to be suppressed quickly by the V substitution. Above x = 0.2, the ordered state is replaced by a spin-glass behaviour with the transition temperature Tg decreasing gradually with increasing x. Tg is one order of magnitude smaller than the Weiss temperature θ, implying the dominant effect of geometrical frustration. The specific heat C of the spin-glass system, CuCr0.7V0.3S2 (x = 0.3), is found to vary as C ∝ T2 below 10 K, similarly to those two-dimensional spin-liquid systems

  16. PIXE and SPM analysis of V, Cr, Cu and Bi in nodular cast iron

    International Nuclear Information System (INIS)

    The nodular cast iron was prepared with the same nodularizing process in which the elements V, Cr, Cu and Bi were added respectively. The graphite phase was extracted from the nodular cast iron to measure the trace elements in it. It was made into a thick target and measured by proton induced X-ray emission (PIXE) analysis. The contents of V, Cr and Cu were 3, 40 and 14 ppm respectively in the graphite, as the element was separately increased to 2100, 5000 and 2500 ppm in the matrix. Therefore, V, Cr and Cu do not intrude the graphite as the contents of these elements are lower, and have no obvious effect on the nodularization. Bi, which belongs to the antinodular elements, easier intrudes into the graphite than others. The content of Bi in graphite was 74 ppm and the nodularizing rate went down by 34% when it was 200 ppm in the matrix. The distributions of V, Cr, Cu and Bi in the sample were measured using a scanning proton microprobe (SPM) to research the properties of these elements further. The results showed that most of the V, Cu and Cr distributed in the matrix. Some of the Cu intruded into the graphite, some existed in the matrix yet as Bi was increased to 200 ppm. These results of SPM agree with that of the PIXE analysis. (orig.)

  17. CuCrO{sub 2} as anode material for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Shu Jie [Department of Applied Chemistry, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China) and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)], E-mail: sjshujie@126.com; Zhu Xiaodong [Department of Applied Chemistry, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China) and Science Research Center, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China)], E-mail: zxd9863@163.com; Yi Tingfeng [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan, Anhui 243002 (China)

    2009-04-01

    CuCrO{sub 2} with a delafossite structure was synthesized by a sol-gel technique. It shows different Li insertion/extraction behavior with those of CuCr{sub 2}O{sub 4} and Cr{sub 2}O{sub 3}. Based on the ex situ X-ray diffraction (XRD) analysis, it is obvious that there are two different phase transformations upon initial and subsequent cycling, respectively. A reversible capacity of 304 mAh g{sup -1} can be achieved for the pure CuCrO{sub 2} after 25 cycles. Through carbon coating, the Li-storage capacity per unit is improved from 1.67 Li to 2.28 Li (415 mAh g{sup -1}) and almost no capacity loss is observed during charge/discharge cycling.

  18. Improved CuCrZr / 316L Transition for Plasma Facing Components

    International Nuclear Information System (INIS)

    Plasma Facing Components used in all advanced nuclear fusion experiments and in particular for ITER consist of heat sinks made of the precipitation hardened CuCrZr alloy. This material has been selected due to the requirements regarding thermal and mechanical properties with and without the presence of neutrons. The divertor parts which are highly heat loaded are actively cooled and are assembled onto weld stainless steel pressure vessels of grade 316L. Therefore these plasma facing parts need a transition in the cooling pipes from CuCrZr to 316L which withstands the internal pressure, the fatigue loads and remains leak tight during operation. As direct fusion welding of CuCrZr with 316L is regarded as critical due to metallurgical issues, the current design uses a transition of Ni - sleeve which is welded onto the CuCrZr and 316L, respectively. However, there is still some concern for the mechanically constraint region of the inlet coolant that this intermediate adapter is the weakest point and could fail due to strongly localised plasticity. The aim of this project is to investigate alternative solutions for the transition of CuCrZr / 316L, to down-select the most promising candidate and finally qualify a new improved tubular transition system. Basic EB welding experiments have been carried out on CuCrZr / 316L tubular samples using different adapter and filler materials. The adapter materials, e.g. Inconel 625 and Monel K500, were chosen due to their high temperature strength and good weldability with respect to Cu - alloys and austenitic steels. In case of the investigated filler metals Ni and Ti the intention was to control the dilution and to produce a fine grained weld zone with no formation of detrimental phases. As a further option the use of an explosively welded CuCrZr/316L adapter was evaluated. The application of such an adapter would simplify the issue to the welding of CuCrZr / CuCrZr and 316L / 316L respectively. In the characterisation programme

  19. First-principles study of roles of Cu and Cl in polycrystalline CdTe

    International Nuclear Information System (INIS)

    Cu and Cl treatments are important processes to achieve high efficiency polycrystalline cadmium telluride (CdTe) solar cells, thus it will be beneficial to understand the roles they play in both bulk CdTe and CdTe grain boundaries (GBs). Using first-principles calculations, we systematically study Cu and Cl-related defects in bulk CdTe. We find that Cl has only a limited effect on improving p-type doping and too much Cl can induce deep traps in bulk CdTe, whereas Cu can enhance p-type doping of bulk CdTe. In the presence of GBs, we find that, in general, Cl and Cu will prefer to stay at GBs, especially for those with Te-Te wrong bonds, in agreement with experimental observations

  20. First-principles study of roles of Cu and Cl in polycrystalline CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ji-Hui; Park, Ji-Sang; Metzger, Wyatt [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Yin, Wan-Jian [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); College of Physics, Optoelectronics and Energy and Collaborative, Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Wei, Su-Huai, E-mail: suhuaiwei@csrc.ac.cn [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Beijing Computational Science Research Center, Beijing 100094 (China)

    2016-01-28

    Cu and Cl treatments are important processes to achieve high efficiency polycrystalline cadmium telluride (CdTe) solar cells, thus it will be beneficial to understand the roles they play in both bulk CdTe and CdTe grain boundaries (GBs). Using first-principles calculations, we systematically study Cu and Cl-related defects in bulk CdTe. We find that Cl has only a limited effect on improving p-type doping and too much Cl can induce deep traps in bulk CdTe, whereas Cu can enhance p-type doping of bulk CdTe. In the presence of GBs, we find that, in general, Cl and Cu will prefer to stay at GBs, especially for those with Te-Te wrong bonds, in agreement with experimental observations.

  1. First-principles study of roles of Cu and Cl in polycrystalline CdTe

    Science.gov (United States)

    Yang, Ji-Hui; Yin, Wan-Jian; Park, Ji-Sang; Metzger, Wyatt; Wei, Su-Huai

    2016-01-01

    Cu and Cl treatments are important processes to achieve high efficiency polycrystalline cadmium telluride (CdTe) solar cells, thus it will be beneficial to understand the roles they play in both bulk CdTe and CdTe grain boundaries (GBs). Using first-principles calculations, we systematically study Cu and Cl-related defects in bulk CdTe. We find that Cl has only a limited effect on improving p-type doping and too much Cl can induce deep traps in bulk CdTe, whereas Cu can enhance p-type doping of bulk CdTe. In the presence of GBs, we find that, in general, Cl and Cu will prefer to stay at GBs, especially for those with Te-Te wrong bonds, in agreement with experimental observations.

  2. The Structure-Function Relationships of Complement Receptor Type 2 (CR2; CD21).

    Science.gov (United States)

    Hannan, Jonathan Paul

    2016-01-01

    Human complement receptor type 2 (CR2; CD21) is a surface-associated glycoprotein which binds to a variety of endogenous ligands, including the complement component C3 fragments iC3b, C3dg and C3d, the low-affinity IgE receptor CD23, and the type I cytokine, interferon-alpha. CR2 links the innate complement-mediated immune response to pathogens and foreign antigens with the adaptive immune response by binding to C3d that is covalently attached to targets, and which results in a cell signalling phenomenon that lowers the threshold for B cell activation. Variations or deletions of the CR2 gene in humans, or the Cr2 gene in mice associate with a variety of autoimmune and inflammatory conditions. A number of infectious agents including Epstein-Barr virus (EBV), Human Immunodeficiency Virus (HIV) and prions also bind to CR2 either directly or indirectly by means of C3d-targeted immune complexes. In this review we discuss the interactions that CR2 undertakes with its best characterized ligands C3d, CD23 and the EBV gp350/220 envelope protein. To date only a single physiologically relevant complex of CR2 with one of its ligands, C3d, has been elucidated. By contrast, the interactions with CD23 and EBV gp350/220, while being important from physiologic and disease-associated standpoints, respectively, are only incompletely understood. A detailed knowledge of the structure-function relationships that CR2 undergoes with its ligands is necessary to understand the implications of using recombinant CR2 in therapeutic or imaging agents, or alternatively targeting CR2 to down-regulate the antibody mediated immune response in cases of autoimmunity. PMID:26916158

  3. Magnetic properties and hyperfine interactions in Cr8, Cr7Cd, and Cr7Ni molecular rings from 19F-NMR

    Science.gov (United States)

    Bordonali, L.; Garlatti, E.; Casadei, C. M.; Furukawa, Y.; Lascialfari, A.; Carretta, S.; Troiani, F.; Timco, G.; Winpenny, R. E. P.; Borsa, F.

    2014-04-01

    A detailed experimental investigation of the 19F nuclear magnetic resonance is made on single crystals of the homometallic Cr8 antiferromagnetic molecular ring and heterometallic Cr7Cd and Cr7Ni rings in the low temperature ground state. Since the F- ion is located midway between neighboring magnetic metal ions in the ring, the 19F-NMR spectra yield information about the local electronic spin density and 19F hyperfine interactions. In Cr8, where the ground state is a singlet with total spin ST = 0, the 19F-NMR spectra at 1.7 K and low external magnetic field display a single narrow line, while when the magnetic field is increased towards the first level crossing field, satellite lines appear in the 19F-NMR spectrum, indicating a progressive increase in the Boltzmann population of the first excited state ST = 1. In the heterometallic rings, Cr7Cd and Cr7Ni, whose ground state is magnetic with ST = 3/2 and ST = 1/2, respectively, the 19F-NMR spectrum has a complicated structure which depends on the strength and orientation of the magnetic field, due to both isotropic and anisotropic transferred hyperfine interactions and classical dipolar interactions. From the 19F-NMR spectra in single crystals we estimated the transferred hyperfine constants for both the F--Ni2+ and the F--Cd2+ bonds. The values of the hyperfine constants compare well to the ones known for F--Ni2+ in KNiF3 and NiF2 and for F--Cr3+ in K2NaCrF6. The results are discussed in terms of hybridization of the 2s, 2p orbitals of the F- ion and the d orbitals of the magnetic ion. Finally, we discuss the implications of our results for the electron-spin decoherence.

  4. First-Principles Study on Cd Doping in Cu2ZnSnS4 and Cu2ZnSnSe4

    Science.gov (United States)

    Maeda, Tsuyoshi; Nakamura, Satoshi; Wada, Takahiro

    2012-10-01

    To quantitatively evaluate the substitution energies of Cd atom for Cu, Zn, or Sn atom in indium-free photovoltaic semiconductors Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe), first-principles pseudopotential calculations using plane-wave basis functions were performed. The substitution energies of Cd atom in kesterite-type CZTS and CZTSe were calculated in consideration of the atomic chemical potentials of the constituent elements of Cu, Zn, Sn, and the doping atom of Cd. During the chemical bath deposition (CBD) of the CdS layer on the CZTS or CZTSe layer, Cu, Zn, and Cd atoms dissolved in the ammonia aqueous solution and formed [Cu(NH3)2]+, [Zn(NH3)4]2+, and [Cd(NH3)4]2+ complex ions. Therefore, the chemical potentials of Cu, Zn, and Cd atoms in [Cu(NH3)2]+, [Zn(NH3)4]2+, and [Cd(NH3)4]2+ complex ions were calculated. We found that the substitution energies of n-type CdCu and charge-neutral CdZn in CZTS and CZTSe are smaller than that of p-type CdSn. The substitution energies of CdCu in CZTS and CZTSe are smaller than that in chalcopyrite-type CuInSe2 (CIS). However, the substitution energies of CdCu, CdZn, and CdSn are positive values. The formation energy of charge-neutral Cd doping with the Cu vacancy (CdCu + VCu) pair is a negative value and greatly smaller than those of donor-type CdCu and neutral CdZn in CZTS and CZTSe. These results indicate that the charge-neutral (CdCu + VCu) vacancy pair is easily formed during the CBD of the CdS layer on the CZTS or CZTSe layer. A small amount of n-type CdCu and neutral CdZn would also be formed.

  5. Advances in CuInSe sub 2 and CdTe thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Shafarmann, W.N.; Birkmire, R.W.; Farding, D.A.; McCandless, B.E.; Mondal, A.; Phillips, J.E.; Varrin, R.D. Jr. (Delaware Univ., Newark (USA). Inst. of Energy Conversion)

    1991-05-01

    Research on CuInSe{sub 2} and CdTe thin film solar cells is discussed. CuInSe{sub 2} was deposited by selenization of Cu/In layers and was used to make a 10% efficient CuInSe{sub 2}/(CdZn)S cell. Characterization of the reaction mechanisms is described. The open-circuit voltage V{sub oc} of CuInSe{sub 2}/(CdZn)S cells is dominated by recombination in the space charge region, so increassing the band gap or decreasing the width of this region should increase V{sub oc}. Increasing the band gap with a thin Cu(InGa)Se{sub 2} layer at the CuInSe{sub 2} surface has demonstrated increased V{sub oc} with collection out to the CuInSe{sub 2} band gap. A post-deposition treatment and contacting process for evaporated CdS/CdTe cells was developed and high efficiency cells were made. Several steps in the process, including a CdCl{sub 2} coating, a 400deg C heat treatment, and a contact containing copper are critical. ZnTe films were deposited from an aqueous solution as a contact to CdTe. (orig.).

  6. Distribution of trace elements Cu, Cr and Bi in nodular cast iron by SPM (Scanning Proton Microprobe) analysis

    International Nuclear Information System (INIS)

    The distributions of trace elements in nodular graphite have been measured using SPM. The results showed that most of Cu and Cr were distributed in matrix, and some of Cu intruded into nodular graphite as antinodularizing element Bi was increased

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

    International Nuclear Information System (INIS)

    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

  8. 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.

  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. Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system

    Science.gov (United States)

    Dhar, S. K.; Provino, A.; Manfrinetti, P.; Kulkarni, R.; Goyal, Neeraj; Paudyal, D.

    2016-05-01

    Ti3CrCu4 is a new ternary compound which crystallizes in the tetragonal Ti3Pd5 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, μeff = 1.1 μB, a low paramagnetic Curie temperature θP (below 7 K) and a temperature independent χ0 = 6.7 x 10-4 emu/mol. The magnetization at 1.8 K increases rapidly with field nearly saturating to 0.2 μB/f.u. The zero field heat capacity C/T shows an upturn below 7 K (˜190 mJ/mol K2 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 Ti3CrCu4, 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 Ti3CrCu4 to become magnetic.

  11. Identification of the complement iC3b binding site in the beta 2 integrin CR3 (CD11b/CD18).

    OpenAIRE

    Ueda, T.; Rieu, P.; Brayer, J.; Arnaout, M. A.

    1994-01-01

    The divalent cation-dependent interaction of the beta 2 integrin CR3 (CD11b/CD18) with the major complement opsonic C3 fragment iC3b is an important component of the central role of CR3 in inflammation and immune clearance. In this investigation we have identified the iC3b binding site in CR3. A recombinant fragment representing the CR3 A-domain, a 200-amino acid region in the ectodomain of the CD11b subunit, bound to iC3b directly and in a divalent cation-dependent manner. The iC3b binding s...

  12. Transparent ferrimagnetic semiconducting CuCr2O4 thin films by atomic layer deposition

    Science.gov (United States)

    Tripathi, T. S.; Yadav, C. S.; Karppinen, M.

    2016-04-01

    We report the magnetic and optical properties of CuCr2O4 thin films fabricated by atomic layer deposition (ALD) from Cu(thd)2, Cr(acac)3, and ozone; we deposit 200 nm thick films and anneal them at 700 °C in oxygen atmosphere to crystallize the spinel phase. A ferrimagnetic transition at 140 K and a direct bandgap of 1.36 eV are determined for the films from magnetic and UV-vis spectrophotometric measurements. Electrical transport measurements confirm the p-type semiconducting behavior of the films. As the ALD technique allows the deposition of conformal pin-hole-free coatings on complex 3D surfaces, our CuCr2O4 films are interesting material candidates for various frontier applications.

  13. Half-metallic antiferromagnetism in double perovskite BiPbCrCuO6

    International Nuclear Information System (INIS)

    The electronic structure and magnetic properties of BiPbCrCuO6 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 BiPbCrCuO6 double perovskite. The HM-AFM property of the double perovskite is caused by the double-exchange mechanism between neighboring Cr5+(t2g1↓) and Cu2+(t2g3↑t2g3↓eg2↑eg↓) via the intermediate O2−(2s22p6) ion

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

    International Nuclear Information System (INIS)

    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 CrO42- 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 Ca3(AsO4)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

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

    Science.gov (United States)

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

    2005-10-17

    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 0.6M 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 CrO4(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 Ca3(AsO4)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. PMID:16043281

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yufeng [College of Mechanical Engineering, Shanghai University of Engineering Science, Shanghai, 201620 (China); Hang, Tao, E-mail: hangtao@sjtu.org [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China); Li, Feng; Li, Ming [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China)

    2013-04-15

    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. Preparation and thermoelectric properties of ternary superionic conductor CuCrS2

    International Nuclear Information System (INIS)

    Transition metal chalcogenide CuCrS2 powder was synthesized by mechanical alloying (MA) and then consolidated by spark plasma sintering (SPS) technique at 673–1073 K. The phase structure, microstructure and thermoelectric properties of samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Seebeck coefficient/electrical conductivity measuring system, respectively. All the bulks indicated a single phase CuCrS2, while the high relative density over 90% were attained for the samples sintered at 873–1073 K. The electrical conductivity of bulk samples displayed a typical characteristic of semiconductor. With increasing measuring temperature, the conductive behaviour of bulk samples sintered over 973 K showed a semiconductor transformation from n-type to p-type due to the changes of main carrier type. The sample obtained by applying SPS at 873 K got the highest power factor 83.2 μW m−1 K−2, and the largest ZT value 0.11 at 673 K. - Graphical abstract: The samples sintered above 873 K, both of the Seebeck coefficient and electrical conductivity exhibit an increase tendency with increasing temperature, which is due to the mechanism of mix-conduction for CuCrS2. Highlights: ► Single phase CuCrS2 powder was synthesized by ball-milling at 425 rpm for 40 h. ► Dense CuCrS2 bulks were fabricated using SPS techniques at sintering temperature 873–1073 K. ► Seebeck coefficient of CuCrS2 samples sintered over 973 K change the signs. ► Highest power factor reached 83.2 μW m−1 K−2 at 673 K for the sample sintered at 873 K. ► ZT value was 0.11 at 673 K for the sample sintered at 873 K.

  18. Thermodynamic and electrical properties of CuCrTiS4

    International Nuclear Information System (INIS)

    Highlights: • We study thermodynamic and electrical properties of spinel CuCrTiS4. • Electrical resistivity shows insulating temperature dependence. • Thermal conductivity has the contribution from the localized vibration hopping mode. • Thermopower can be reproduced by the Matoba’s model in the wide temperature range. • CuCrTiS4 has a dimensionless figure of merit of 0.01 at 300 K. - Abstract: We studied the electrical resistivity, thermal conductivity, and thermopower of thiospinel CuCrTiS4. Temperature (T) dependence of the electrical resistivity (ρ) is insulating in the whole temperature range we measured, 5CuCrTiS4, with T increasing, monotonically-increasing behaviour as seen in the amorphous compounds is observed in 150KCuCrTiS4 is negative. The absolute value of S(T) has a broad peak caused by phonon drag at around 30 K, and the linear temperature dependence in 80KCuCrTiS4 is ∼0.01 at around 300 K

  19. The impact of Cu on recombination in high voltage CdTe solar cells

    Science.gov (United States)

    Kuciauskas, Darius; Dippo, Pat; Kanevce, Ana; Zhao, Zhibo; Cheng, Long; Los, Andrei; Gloeckler, Markus; Metzger, Wyatt K.

    2015-12-01

    Using photoluminescence spectroscopy, we construct a recombination model for state-of-the-art CdTe solar cells doped with Cu. We observe that Cu on Cd sites form a dominant acceptor state about 150 meV from the valence band. Although it is intuitive that this state can increase hole density, we also find that this relatively shallow dopant can also limit lifetime. Consequently, CdTe solar cells doped with Cu could have a lifetime limitation inversely proportional to the hole concentration.

  20. On the strong impact of doping in the triangular antiferromagnet CuCrO 2

    Science.gov (United States)

    Maignan, A.; Martin, C.; Frésard, R.; Eyert, V.; Guilmeau, E.; Hébert, S.; Poienar, M.; Pelloquin, D.

    2009-06-01

    Electronic band structure calculations using the augmented spherical wave method have been performed for CuCrO 2. For this antiferromagnetic ( TN=24 K) semiconductor crystallizing in the delafossite structure, it is found that the valence band maximum is mainly due to the t 2g orbitals of Cr 3+ and that spin polarization is predicted with 3 μ per Cr 3+. The structural characterizations of CuCr 1- xMg xO 2 reveal a very limited range of Mg 2+ substitution for Cr 3+ in this series. As soon as x=0.02, a maximum of 1% Cr ions are substituted by Mg site is measured in the sample. This result is also consistent with the detection of Mg spinel impurities from X-ray diffraction for x=0.01. This explains the saturation of the Mg 2+ effect upon the electrical resistivity and thermoelectric power observed for x>0.01. Such a very weak solubility limit could also be responsible for the discrepancies found in the literature. Furthermore, the measurements made under magnetic field (magnetic susceptibility, electrical resistivity and Seebeck coefficient) support that the Cr 4+ "holes", created by the Mg 2+substitution, in the matrix of high spin Cr 3+ ( S=3/2) are responsible for the transport properties of these compounds.

  1. Chemical effect on the K shell fluorescence yield of Fe, Mn, Co, Cr and Cu compounds

    Indian Academy of Sciences (India)

    U Turgut

    2004-11-01

    Chemical effects on the K shell fluorescence yields of Fe, Mn, Co, Cr and Cu compounds were investigated. Samples were excited using 59.5 keV energy photons from a 241Am radioisotope source. K X-rays emitted by samples were counted by a Si(Li) detector with a resolution 160 eV at 5.9 keV. Chemical effects on the K shell fluorescence yields (K) for Fe, Mn, Co, Cr and Cu compounds were observed. The values are compared with theoretical, semiempirical fit and experimental ones for the pure elements.

  2. Aging phenomena of rapidly solidified Al-4mass%Cu-Cr alloys

    International Nuclear Information System (INIS)

    The Al-4mass%Cu-(0--4.5)mass%Cr alloys were prepared by chill-casting, and their heat-resisting properties were examined. The amount of solute Cr quenched in Al-4%Cu alloy was about 1.5% at maximum. Resistance to over-aging was markedly increased with increasing amount of solute Cr, when the alloys were subjected to usual heat-treatments: that is, homogenization at 793K after chill-casting, water-quenching, aging at 473K and subsequent over-aging at 623K. This phenomenon would mainly be attributed to the fact that theta' formed during pre-aging became very stable both in the amount and the size, as the amount of solute Cr increased. The chill-cast Al-4%Cu-2%Cr alloy was thought to be superior to commercial heat-resisting 2219 alloy. The over-aged structures of Cr contained alloys were in detail discussed, in comparison with those of Mn contained alloys. (author)

  3. Achieving combined high strength and high conductivity in re-processed Cu-Cr alloy

    Directory of Open Access Journals (Sweden)

    A.O. Olofinjanaa

    2009-07-01

    Full Text Available Purpose: Precipitation hardening by nano-sized precipitates had proven to be the most adequate way to achieve the optimum combination for strength and conductivity in copper based alloys. However, precipitation strengthened Cu- alloys are limited to very dilute concentration 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.Design/methodology/approach: The ingot alloys with Cr content up to 10 wt.% were prepared via semi-chilling of small rods before been cast into ribbon using chill block melt spinner. Thermal aging studies followed by conductivity and microhardness tests were performed to follow the HSHC properties.Findings: 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 processResearch limitations/implications: 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

  4. Divalent Cu, Cd, and Pb Biosorption in Mixed Solvents

    Directory of Open Access Journals (Sweden)

    M. H. Al-Qunaibit

    2009-01-01

    Full Text Available Dead dried Chlorella vulgaris was studied in terms of its performance in binding divalent copper, cadmium, and lead ions from their aqueous or 50% v/v methanol, ethanol, and acetone solutions. The percentage uptake of cadmium ions exhibited a general decrease with decrease in dielectric constant values, while that of copper and lead ions showed a general decrease with increase in donor numbers. Uptake percentage becomes less sensitive to solvent properties the larger the atomic radius of the biosorbed ion, and uptake of copper was the most affected. FT-IR analyses revealed stability of the biomass in mixed solvents and a shift in vibrations of amide(I and (II, carboxylate, glucose ring, and metal oxygen upon metal binding in all media. ΔνCOO values (59–69 cm−1 confirmed bidentate metal coordination to carboxylate ligands. The value of νasCOO increased slightly upon Cu, Cd, and Pb biosorption from aqueous solutions indicating lowering of symmetry, while a general decrease was noticed in mixed solvents pointing to the opposite. M–O stretching frequencies increased unexpectedly with increase in atomic mass as a result of solvent effect on the nature of binding sites. Lowering polarity of the solvent permits variations in metal-alga bonds strengths; the smaller the metal ion, the more affected.

  5. Au/Cu2Te/CdTe/CdS/TCO/Glass Solar Cells with CdIn2O4 Obtained by Sol-Gel as TCO

    OpenAIRE

    Márquez Marín, J.; Torres Delgado, G.; M. A. Aguilar Frutis; Castanedo Pérez, R.; Zelaya Ángel, O.

    2014-01-01

    An Au/Cu2Te/CdTe/CdS/TCO/glass heterostructure based superstrate solar cells with 2.5 mm2 of area, where the CdTe layer was prepared by means of closed spaced sublimation (CSS) and the CdS by chemical bath, reached an efficiency η value of 12.1%. As transparent conductive oxide (TCO), a thin film of cadmium-indium oxide (CdIn2O4:CIO), obtained by sol-gel technique, was used. A systematic optimization of the thermal activation of the CdTe/CdS/CIO central part of the device with a CdCl2 vapor a...

  6. Effect of Cu addition on microstructure and mechanical properties of 15%Cr super martensitic stainless steel

    International Nuclear Information System (INIS)

    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.

  7. 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...

  8. Electrical, optical and structural properties of CuCrO{sub 2} films prepared by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Li Da [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Fang Xiaodong [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Deng Zanhong [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Zhou Shu [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Tao Ruhua [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Dong Weiwei [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Wang Tao [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Zhao Yiping [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Meng Gang [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Zhu Xuebin [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2007-08-21

    Transparent conducting CuCrO{sub 2} thin films were prepared by pulsed laser deposition (PLD) from a nanocrystalline CuCrO{sub 2} target. The derived CuCrO{sub 2} films were highly c-axis oriented deposited at 800 K. The microstructural, electrical as well as optical properties were studied. It was found that the films were relatively smooth and behaved as semiconductors. The energy band of the CuCrO{sub 2} films is constructed based on the Mott-Davis model in order to investigate the conduction mechanism. The transmittances of the films in the visible region are about 60-80% with direct band gaps of about 3.2 eV. The results suggested that CuCrO{sub 2} films could be successfully prepared by the PLD method, which can broaden the applications of the transparent conducting oxide films.

  9. Hot deformation behavior of Cu-Cr-Zr-Ce alloy at elevated temperature%Cu-Cr-Zr-Ce合金高温热变形行为研究

    Institute of Scientific and Technical Information of China (English)

    李瑞卿; 田保红; 张毅; 刘勇; 刘平; 许倩倩; 段秋华

    2013-01-01

    Cu-Cr-Zr系合金是一类高强度高导电集成电路用引线框架铜合金.在Gleeble-1500D热模拟实验机上,采用等温压缩实验研究了Cu-Cr-Zr-Ce合金在变形温度为600~800℃、应变速率为0.01~5s-1条件下的流变应力的相互变化规律,测定了其真应力-应变曲线,并利用光学显微镜分析了合金在热压缩过程中的组织演变规律.结果表明,Cu-Cr-Zr-Ce合金的真应力-真应变曲线呈现典型的动态回复特征,其流变应力和峰值应力随变形温度的降低和应变速率的提高而增大;且变形温度越高,应变速率越小,合金越容易发生动态回复和再结晶.在上述实验基础上,基于流变应力、应变速率和温度的相关性,计算出了该合金热压缩变形时的热变形激活能Q,并建立了其等温压缩塑性变形过程的流变应力与变形温度和应变速率之间关系的本构方程.%Cu-Cr-Zr series copper alloys are usually used as lead frame materials for integrated circuit (IC) with high strength and high electrical conductivity.The flow stress change rules and deformation behavior of the CuCr-Zr-Ce alloy during hot compression deformation were investigated with isothermal compression test method by a Gleeble-1500D thermal-mechanical simulator at elevated temperature.The true stress and true strain curves were measured at the test temperature ranging from 600℃ to 800℃ and the strain rate from 0.01s-1 to 5s 1.The microstructure evolutions of Cu-Cr-Zr-Ce alloy were analyzed with an optical microscope.The results show that the curves of true stress and true strain present characteristics of typical dynamic recovery.The flow stress and the peak flow stress increase with the decrease of deforming temperature and the increase of strain rate.The higher the deforming temperature and the less the strain rate,the easier the dynamic recovery and the dynamic recrystallization taking place.On the basis of the above experimental results,the hot

  10. Magnetic susceptibility of the frustrated spinels ZnCr2O4, MgCr2O4 and CdCr2O4

    International Nuclear Information System (INIS)

    We analyzed the magnetic susceptibilities of several Cr spinels using two recent models for the geometrically frustrated pyrochlore lattice, the Quantum Tetrahedral Mean Field model and a Generalized Constant Coupling model. Both models can describe the experimental data for ACr2O4 (with A Zn, Mg, and Cd) satisfactorily, with the former yielding a somewhat better agreement with experiment for A = Zn, Mg. The obtained exchange constants for nearest and next-nearest neighbors are discussed.

  11. 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.

  12. Influence of Cu2+ dopant in optical property of CdTe quantum dots and photoelectrochemical performance of CdTe:Cu2+/TiO2 nanotube arrays

    Science.gov (United States)

    Chen, Qian; Geng, Yue; Zhou, Chunyan; Song, Jiahui; Zhou, Liya

    2016-05-01

    A novel one-step synthesis process was used to prepare CdTe:Cu2+/TiO2 nanotube arrays (TNTAs). X-ray powder diffraction and high-resolution transmission electron microscopy analyses confirmed that the obtained CdTe:Cu2+ quantum dots (QDs) possess cubic structures, which are approximately spherical, and a small particle size (2.95 nm). The photoluminescent and UV-visible absorption spectra of CdTe:Cu2+ QDs also display an obvious redshift, which was attributed to the replacement of Cd2+ with Cu2+. Compared with that of the TNTAs and CdTe/TNTAs, the photoelectric conversion efficiency of CdTe:5% Cu2+/TNTAs increased by 785.7% and 103.3%, respectively. The incident photo-to-current conversion efficiency of CdTe:5% Cu2+/TNTAs was 50.6%, which indicated the potential use of QDs in photochemical solar cells.

  13. Characterization of Cold Sprayed CuCrAl Coated GRCop-84 Substrates for Reusable Launch Vehicles

    Science.gov (United States)

    Raj, S . V.; Barrett, C. A.; Lerch, B. A.; Karthikeyan, J.; Ghosn, L. J.; Haynes, J.

    2005-01-01

    An advanced Cu-8(at.%)Cr-4%Nb alloy developed at NASA's Glenn Research Center, and designated as GRCop-84, is currently being considered for use as combustor liners and nozzles in NASA's future generations of reusable launch vehicles (RLVs). Despite the fact that this alloy has superior mechanical and oxidation properties compared to many commercially available copper alloys, it is felt that its high temperature and environmental resistance capabilities can be further enhanced with the development and use of suitable coatings. Several coatings and processes are currently being evaluated for their suitability and future down selection. A newly developed CuCrAl has shown excellent oxidation resistance compared to current generation Cu-Cr coating alloys. Cold spray technology for depositing the CuCrAl coating on a GRCop-84 substrate is currently being developed under NASA's Next Generation Launch Technology (NGLT) Propulsion Research and Technology (PR&T) project. The microstructures, mechanical and thermophysical properties of overlay coated GRCop-84 substrates are discussed.

  14. Electrokinetic Treatment of Cr-, Cu-, and Zn-Contaminated Sediment: Cathode Modification.

    Science.gov (United States)

    Rajić, Ljiljana; Dalmacija, Božo; Perović, Svetlana Ugarčina; Krčmar, Dejan; Rončević, Srđan; Tomašević, Dragana

    2013-12-01

    Enhanced electrokinetic (EK) removal of Cr, Cu, and Zn from sediment by using original and modified integrated ion exchange (IIX™) cathodes was investigated. IIX cathode design and EK device process modifications were made to improve performance: separation of IIX cathode components (IIXS), combination of modified IIX cathode with pulsed electric field (IIXSP), and separation of IIX cathode components with addition of an anion exchange resin compartment (IIXA). After using the IIXSP, overall Cr, Cu, and Zn removal efficacies were significantly improved compared with the other treatments investigated. No improvements in overall Cr, Cu, and Zn removal efficacies were achieved by utilization of IIXA. Nevertheless, significant removal efficacies occurred at the anode region since distribution of the alkaline front was prevented. However, metal accumulation in the cathode region occurred. This was a consequence of metal cation complexation with Cl(-) released from the anion exchange resin that changed the direction of metal migration. Enhancing EK remediation of Cr-, Cu-, and Zn-contaminated sediment can be achieved by using a modified IIX cathode. PMID:24381480

  15. A thermodynamic approach to energy storage on mechanical alloying of the Cu-Cr system

    International Nuclear Information System (INIS)

    The object of this work is to estimate the increase in new surface and elastic energy during mechanical alloying of Cu-Cr powders processed by means of a SPEX mill in comparison with a regular solution model. The presence of crystalline defects increases the Gibbs free energy and the Gibbs free energy curves are moved upwards; hence the solubility limit changes

  16. Effects of heat treatment on diffusion of Cu atoms into CdTe single crystals

    International Nuclear Information System (INIS)

    Angular dependence of x-ray fluorescence and x-ray absorption fine structure techniques have been used to study the diffusion of Cu atoms into the photovoltaic material CdTe. Depth profile, effective valency, and local structure of Cu atoms in a Cu-doped single crystal of CdTe were investigated before and after a second heat treatment. Enhanced Cu diffusion into the CdTe single crystal was observed as a result of heating at a moderate temperature around 200 degree sign C, resulting in a redistribution of the Cu impurities through a broader depth profile. Some of the Cu atoms are believed either to form small complexes with Te or occupy interstitial sites in the host but accompanied by a large local lattice distortion while others substitute for Cd on the cation sites. The results thus demonstrate that these nondestructive x-ray characterization methods are useful for probing microstructural changes in CdTe photovoltaic materials/devices in which some Cu-containing compounds are used as back contacts. (c) 2000 American Institute of Physics

  17. PENINGKATAN KUALITAS FILM TIPIS CdTe SEBAGAI ABSORBER SEL SURYA DENGAN MENGGUNAKAN DOPING TEMBAGA (Cu

    Directory of Open Access Journals (Sweden)

    P. Marwoto

    2012-12-01

    Full Text Available Film tipis CdTe dengan doping tembaga (Cu berkonsenterasi 2% telah berhasil ditumbuhkan di atas substrat Indium Tin Oxide (ITO dengan metode dc magnetron sputtering. Penelitian ini dilakukan untuk mengetahui pengaruh doping Cu(2% terhadap struktur morfologi, struktur kristal, fotoluminisensi dan resistivitas listrik film CdTe. Citra morfologi Scanning Electron Microscopy (SEM dan hasil analisis struktur dengan X-Ray Diffraction (XRD menunjukkan bahwa film CdTe:Cu(2% mempunyai citra permukaan dan struktur kristal yang lebih sempurna dibandingkan film CdTe tanpa doping. Hasil analisis spektrometer fotoluminisensi menunjukkan bahwa film CdTe dan CdTe(2% mempunyai puncak fotoluminisensi pada tiga panjang gelombang yang identik yaitu 685 nm (1,81 eV, 725 nm (1,71 eV dan 740 nm (1,67 eV. Film CdTe dengan doping Cu(2% memiliki intensitas puncak fotoluminisensi yang lebih tajam pada pita energi 1,81 eV dibandingkan dengan film CdTe tanpa doping. Pengukuran arus dan tegangan (I-V menunjukkan bahwa pemberian doping Cu(2% dapat menurunkan resistivitas film dari 8,40x109 Ωcm menjadi 6,92x105 Ωcm. Sebagai absorber sel surya, kualitas film tipis CdTe telah berhasil ditingkatkan dengan pemberian doping Cu(2%.CdTe:Cu(2% thin film has been successfully grown on Indium Tin Oxide (ITO substrates by using dc magnetron sputtering. This study was carried out in order to investigate the effect of Cu(2% doping on the morphologycal structure, crystal structure, photoluminesence, and resistivity of CdTe thin film. Scanning Electron Microscopy (SEM  images and X-Ray Diffraction (XRD results showed that CdTe:Cu(2% thin film has morphologycal and crystal structures more perfect than undoped CdTe film. Photoluminesence spectroscopy results showed that CdTe and CdTe:Cu(2% thin films have luminesence peak at three identical wevelength regions i.e. 685 nm (1.81 eV, 725 nm (1.71 eV and 740 nm (1.67 eV however CdTe:Cu(2% film shows sharper photoluminescence peak at band

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

    International Nuclear Information System (INIS)

    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−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−1 Cd, 2 mg kg−1 Cr and 15 mg kg−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

  19. On characteristics of PVA/CdS and PVA/CdS:Cu nanocomposites for applications as LED

    Energy Technology Data Exchange (ETDEWEB)

    Kakati, Jumi, E-mail: jumikakati@gmail.com [Department of Electronics and Communication Technology, Gauhati University, Guwahati-781014, Assam (India); Datta, Pranayee [Department of Electronics and Communication Technology, Gauhati University, Guwahati-781014, Assam (India)

    2013-06-15

    We report the synthesis of poly vinyl alcohol/cadmium sulphide (PVA/CdS) and polyvinyl alcohol/cadmium sulphide:copper (PVA/CdS:Cu) nanocomposites by chemical route. Characterizations are done by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), ultra violet–visible (UV–VIS), photoluminescence (PL), energy dispersive X-ray spectroscopy (EDS) and selected area electron diffraction (SAED). Sizes of the fabricated nanoparticles (NCs) obtained from XRD are in good agreement with those from TEM/HRTEM and confinement is found to be strong in some samples. The photoluminescence (PL) spectra show luminescence from band edge emission (481 nm) as well as from trap levels caused by sulpher vacancies (510 nm, 538 nm, 572 nm) and from defect states in case of doped sample (500 nm). The photoluminescence and electroluminescence (EL) spectra without as well as with applied (DC) bias are also studied using platinum electrodes in liquid samples. Results indicate that peak position remains same in both the cases of PL and EL and intensity is roughly an increasing function of excitation voltage. Encouraged by the results obtained so far, which indicates possible applications of the samples fabricated as LED, nano devices with ITO/N,N′-bis(3 methylphenyl)–N,N′-bis(phenyl)benzidine (TPD)/NC/Al have been fabricated to study the EL spectra. Operating voltages for PVA/CdS light emitting device (LED) is 0.2 V and for PVA/CdS:Cu light emitting device (LED) is 0.1 V. The emission dominantly belongs to CdS nanocrystals (NCs). Highest external quantum efficiency estimated for the PVA/CdS nanocomposites LED is 0.0024%. The highest external quantum efficiency gets increased upto 0.0027% after doping the PVA/CdS nanocomposites with Cu. -- Highlights: ► We synthesized CdS and CdS:Cu nanocrystals by chemical route method. ► PL and EL are found in the same position. ► Emission

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

    International Nuclear Information System (INIS)

    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

  1. Stability testing of ZnTe:N as a Cu-free back contact to CdTe/CdS solar cells

    Science.gov (United States)

    Simmons, D. A.

    2000-03-01

    Most CdTe/CdS solar cell devices use Cu as a back contact, but recent studies have suggested Cu may cause instabilities in the device under some extreme conditions. We have used rf-sputter deposited ZnTe:N as an alternative back contact to CdTe/CdS solar cells. Identical CdTe/CdS solar cells were back-contacted with ZnTe:N or a standard Cu/Au contact. Sets of both types of cells were subjected to either 3000 hours of baking at 100 C in the dark, or 3000 hours of light-soaking at 1 sun. While initial efficiencies of the Cu cells were slightly higher than the ZnTe:N cells, the ZnTe:N cells performed much better after baking and equally as well after light-soaking as the Cu cells.

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

    OpenAIRE

    Xiaojun Zhu; Xiaoping Zou; Hongquan Zhou

    2015-01-01

    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 sensitize...

  3. 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.

  4. Removal of Cd, Cr, and Pb from aqueous solution by unmodified and modified agricultural wastes.

    Science.gov (United States)

    Mahmood-Ul-Hassan, Muhammad; Suthor, Vishandas; Rafique, Ejaz; Yasin, Muhammad

    2015-02-01

    The adsorption of cadmium (Cd), chromium (Cr), and lead (Pb), widely detected in wastewater, by unmodified and modified banana stalks, corn cob, and sunflower achene was explored. The three agricultural wastes were chemically modified with sodium hydroxide (NaOH), in combination with nitric acid (HNO3) and sulfuric acid (H2SO4), in order to improve their adsorptive binding capacity. The experiments were conducted as a function of contact time and initial metal ion concentrations. Of the three waste materials, corn cob had the highest adsorptive capacity for Pb than Cr and Cd. The NaOH-modified substrates had higher adsorptive capacity than the acid modified samples. The chemical treatment invariably increased the adsorption capacity between 10 and 100 %. The Langmuir maximum sorption capacity (q m) of Pb was highest (21-60 mg g(-1) of banana, 30-57 mg g(-1) of corn cob, and 23-28 mg g(-1) of sunflower achene) and that of Cd was least (4-7 mg g(-1) of banana, 14-20 mg g(-1) of corn cob, and 11-16 mg g(-1) of sunflower achene). The q m was in the order of Pb > Cr > Cd for all the three adsorbents. The results demonstrate that the agricultural waste materials used in this study could be used to remediate water polluted with heavy metals. PMID:25626568

  5. Fabrication of CdS/CdTe solar cells with transparent p-type conductive BaCuSeF back contact

    Science.gov (United States)

    Yamamoto, Koichi; Sakakima, Hiroshi; Ogawa, Yohei; Hosono, Aikyo; Okamoto, Tamotsu; Wada, Takahiro

    2015-08-01

    BaCuSeF films were applied to CdS/CdTe solar cells as back electrodes. The interfaces between the CdTe and BaCuSeF layers in the CdS/CdTe solar cells with BaCuSeF back contact deposited at substrate temperatures (TS) of 200 and 300 °C were analyzed by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). We clearly observed many dislocations in the CdTe layer in the CdS/CdTe solar cell with the BaCuSeF layer deposited at TS = 300 °C. We also observed a reaction layer of Cu2.72Te2 between the BaCuSeF and CdTe layers in both solar cells. We concluded that (1) the substrate temperature for the pulsed laser deposition of the BaCuSeF layer and (2) the interface between the CdTe and BaCuSeF layers are important factors for the performance of the CdTe solar cells. We obtained high conversion efficiency of 8.31% for a solar cell with a BaCuSeF layer deposited at TS = 200 °C on a CdTe surface etched in a NH3 aqueous solution. The highest conversion efficiency of 9.91% was obtained for a solar cell with a CdTe surface etched in a bromide-bromate solution.

  6. Influence of Al{sub 2}O{sub 3} reinforcement on precipitation kinetic of Cu-Cr nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Sheibani, S., E-mail: ssheibani@ut.ac.ir [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Ataie, A.; Heshmati-Manesh, S. [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Caballero, A.; Criado, J.M. [Instituto de Ciencia de Materiales de Sevilla, Departamento de Quimica Inorganica, CSIC - Universidad de Sevilla, Americo Vespucio 49 Sevilla (Spain)

    2011-11-10

    Highlights: Black-Right-Pointing-Pointer Cr precipitation in Cu-1 wt.% Cr solid solution is based on nucleation and growth models. Black-Right-Pointing-Pointer The overall ageing process is accelerated by the presence of Al{sub 2}O{sub 3} reinforcement. Black-Right-Pointing-Pointer Al{sub 2}O{sub 3}-Cu interfaces act as primary nucleation sites. Black-Right-Pointing-Pointer Structural defects act as secondary nucleation sites. - Abstract: In this paper, the kinetic of precipitation process in mechanically alloyed Cu-1 wt.% Cr and Cu-1 wt.% Cr/3 wt.% Al{sub 2}O{sub 3} solid solution was compared using differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The ageing kinetics in Cu-Cr and Cu-Cr/Al{sub 2}O{sub 3} can be described using Johnson-Mehl-Avrami (JMA) and Sestak-Berggren (SB) models, respectively. These different behaviors have been discussed in details. It was found that in presence of Al{sub 2}O{sub 3} reinforcement, the ageing activation energy is decreased and the overall ageing process is accelerated. This behavior is probably due to higher dislocation density previously obtained during ball milling and Al{sub 2}O{sub 3}-Cu interface. TEM observations confirm that Al{sub 2}O{sub 3}-Cu interface and structural defects act as a primary and secondary nucleation sites, respectively.

  7. Sputtered CdTe thin film solar cells with Cu2Te/Au back contact

    International Nuclear Information System (INIS)

    In this work, Cu2Te/Au back contact for CdTe thin film solar cells were prepared by vacuum evaporation. Influence of annealing temperature on the structure and electrical properties of Cu2Te films were investigated by field emission scanning electron microscope, X-ray diffraction, and Hall effect measurement. Also, CdS/CdTe thin film solar cells were fabricated by magnetron sputtering process, which is favorable for large area deposition and mass production, and the photovoltaic characteristics were studied. As the annealing temperature was increased, the crystal structure transformed from Cu2Te for as-deposited film to Cu2−xTe hexagonal phase, and the grains in the film became bigger. The electrical resistivity was slightly higher by the annealing. The cell efficiency was significantly improved by the heat treatment, and showed a maximum value of 9.14% at 180 °C. From these results, Cu2Te/Au contact acts as the proper pseudo-ohmic contact onto CdTe film. However, further increase of annealing temperature caused the deterioration of cell performance. - Highlights: • Annealing effects of the vacuum evaporated Cu2Te films were investigated. • The transformation from Cu2Te to Cu2−xTe hexagonal phase occurred by annealing. • The performance of the solar cell was highly increased by annealing at 180 °C. • Cu2Te/Au contact acts as the proper pseudo-ohmic contact onto CdTe film

  8. Preparation and characterization of CuCrO2/TiO2 heterostructure photocatalyst with enhanced photocatalytic activity

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • p-CuCrO2/n-TiO2 heterostructure photocatalysts were fabricated for the first time. • The p–n heterojunctions were formed between CuCrO2 nanoparticle and TiO2 nanorod. • The degradation activity of CuCrO2/TiO2 was much higher than that of pure TiO2. • CuCrO2/TiO2 has better separation efficiency of photogenerated electron and hole. - Abstract: A series of novel p-type CuCrO2/n-type TiO2 heterostructure photocatalysts were fabricated for the first time by depositing CuCrO2 nanoparticles on TiO2 nanorod-array film through a facile spin-coating method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and photocurrent response were employed to characterize the as-synthesized composites. The photocatalytic activity of CuCrO2/TiO2 for degradation of methylene blue (MB) aqueous solution was much higher than pure TiO2, which could be ascribed to the formation of p–n heterojunctions between CuCrO2 nanoparticles and TiO2 nanorods. In particular, the best degradation efficiency of CuCrO2/TiO2 heterojunction was 85.3%, about 1.14 times higher than pure TiO2 (74.6%), which could be attributed to their high separation efficiency of photogenerated electrons and holes. It is expected this strategy of p–n junction for enhancing photocatalytic activity can have considerable impact to promote the development of high efficient photocatalyst and industrial application for degrading pollutant, treating waste water and other environmental protection fields

  9. Hydrogen photo-evolution over the spinel CuCr2O4

    International Nuclear Information System (INIS)

    The photocatalytic H2 evolution over CuCr2O4 has been studied in connection with some physical properties. The black oxide is classified as a narrow band gap semiconductor crystallizing in the normal spinel structure. The photoactivity is dependent on the preparative conditions through the surface area of the powder and CuCr2O4 has been synthesized by nitrate route. The conductivity varies exponentially with temperature indicating an extrinsic conductivity between mixed valences states Cr3+/4+ located in octahedra sharing common corners. The oxide exhibits p-type conductivity with an activation energy of 0.20 eV and a hole mobility of 2.14 x 10-8 cm2/V s thermally activated. CuCr2O4 shows an excellent chemical stability, a corrosion potential of -0.775 VSCE and an exchange current density of 16 μA cm-2 have been determined from the semilogarithm plot. The capacitance measurement (C-2-V), performed in basic electrolyte, exhibits a linear behavior from which a flat band potential of 0.48 VSCE was obtained. CuCr2O4 is photoelectrochemically stable by hole consumption reactions involving X2- (=SO32- and S2O32-) as hole scavengers. The best catalytic performance for H2-photoproduction was obtained in (NaOH 0.5 M, Na2S2O3 0.025 M) with an average rate of 0.013 cm3 h-1 (mg catalyst)-1 and a quantum efficiency of 0.2% under polychromatic light. S2O32- is oxidized to SO32- and subsequently to SO42- as proven by the dual slopes in the Tafel plot. The system shows a tendency towards saturation whose deceleration is the result of the competitive reductions of the end products namely S2O62- and S2O42- with the water discharge

  10. Pathways toward higher performance CdS/CdTe devices: Te exposure of CdTe surface before ZnTe:Cu/Ti contacting

    International Nuclear Information System (INIS)

    Many studies of thin-film CdS/CdTe photovoltaic devices have suggested that performance may be improved by reducing recombination due to Te-vacancy (VTe), Te antisite (TeCd), or Te-interstitial (Tei) defects. Although formation of these intrinsic defects is likely influenced by CdTe deposition parameters, it may be also coupled to the formation of beneficial cadmium vacancy (VCd) defects. In this study, we expose the CdTe surface to Te vapor prior to ZnTe:Cu/Ti contact-interface formation with the goal of reducing VTe without significantly reducing VCd. Initial results show that when this modified contact is used on a CdCl2-treated CdS/CdTe device, poorer device performance results. This suggests two things: First, the amount of free-Te available during contact formation (either from chemical etching or CuxTe or ZnTe deposition) may be a more important parameter to device performance than previously appreciated. Second, if processes have been used to reduce the effect of VTe (e.g., oxygen and chlorine additions), adding even a small amount of Te may produce detrimental defects. - Highlights: ► Te exposure of CdS/CdTe back contact reduces device performance. ► Field strength and minority carrier lifetime reduced. ► Calculations suggest formation of Te on Cd antisite defect

  11. Melt separation phenomena in CoNiCuAlCr high entropy alloy containing silver

    International Nuclear Information System (INIS)

    The effects of Ag additions to AlCoCrCuNi or AlCoCrCuFeNi high entropy (HE) alloys are described. It is shown that Ag additions to these HE alloys results in liquid phase separation (LPS) into two melts, namely, an AlCoCr(Fe) rich liquid (L1) and a second liquid enriched in Ag and Cu (L2). Further, since the L2 has a higher density and a lower melting temperature, it tends to flow to the bottom of the arc melted buttons due to liquid flow (a) along the outer surface of the unmelted L1 and (b) through the interdendritic channels. In addition to the primary macroscopic LPS, secondary (within the different primary liquids) melt separation was observed in the two melts: the upper L1 layer contained L2 spheres which tended to sink to the fusion line while the L2 melt layer found at the bottom of the buttons contained L1 spheres which tended to float to the top of the L2 layer. The L1 microstructure and microhardness resembles that of an Ag-free AlCoCrCuFeNi HE alloy. In spite of the melt separation, relatively simple microstructures were obtained from the two different liquids; these are described in light of the current understanding of this class of alloys. Finally, the possibility of metastable LPS in a Cu-rich HE alloy using electron beam surface melting, which is known to produce significant dynamic undercoolings on the order of 150 °C, was investigated but was not observed.

  12. Absorption Reduction Capacity with Chromium (Cr and Cadmium (Cd Contaminants of Vetiver Phytoremediation Process on Compost Soil

    Directory of Open Access Journals (Sweden)

    Ahamad Zubair

    2016-01-01

    Full Text Available This study aims to analyze the large of reduction capacity of chromium metals and cadmium in the soil compost media and absorption capacity of chrome and cadmium in phytoremediation process of vetiver; to compare the reduction-absorption capacities of chromium and cadmium metals in phytoremediation process of vetiver (Vetivera zizanioides. The study was carried out for 2 months with a range of sampling every 7 days, and then analyzed by using Atomic Absorption Spectrophotometer (AAS. Contaminants used as artificial contaminants containing heavy metals chromium (Cr and cadmium (Cd. This study is an experimental research includes two variables. First, the variations of Cr concentrations used were 400 ppm, 600 ppm and 800 ppm and Cd concentrations used were 40 ppm, 60 ppm, 800 ppm. Secondly, the variations of total plant are 3, 6, and 9 plant. The period of observation is made every week. Planting media used is compost soil with compost and clay composition of 20%, 30% and 40%. The results of study showed that there are a significant relationship between the reduction capacity of Cr and Cd of compost soil and the absorption capacity of Cr and Cd for vetiver (Vetiveria zizanioides. The higher of Cr and Cd decreases in soil followed by increased levels of Cr and Cd in vetiver (Vetiveria zizanioides. The capacity of Cr reduction varies between 57% - 86% and Cd 36% - 64% where as the absorption capacity of vetiver on Cr between 38% - 75% and Cd between 34%-74%. The capacity of reduction-absorption of Cr is relatively higher than Cd in phytoremediation process of vetiver.

  13. Diffusion in CdS of Cd and S vacancies and Cu, Cd, Cl, S and Te interstitials studied with first-principles computations

    International Nuclear Information System (INIS)

    We present an ab initio study of the diffusion profiles in CdS of native, Cd and S vacancies, and interstitial adatoms Cd, S, Te, Cu, and Cl. The global minimum and saddle point positions in the bulk unit cell vary for different diffusing species. This results in a significant variation, in the bonding configurations and associated strain energies of different extrema positions along the diffusion paths for various defects. The rate-limiting diffusion barriers range from a low of 0.42 eV for an S interstitial to a high of 2.18 eV for a S vacancy. The rate-limiting barrier is 0.66 eV for Cu and Te interstitials, 0.76 eV for Cl interstitial, 0.87 eV for Cd interstitial and 1.09 eV for the Cd vacancy. The 0.66 eV barrier for a Cu interstitial is in good agreement with experimental values in the range of 0.58–0.96 eV reported in the literature. We report an electronic signature in the projected density of states for the s-and d-states of the Cu interstitial at the saddle point and global minimum energy position. In addition, we have examined the relative charge transfer experienced by the interstitials at the extrema positions through Bader analysis. (papers)

  14. 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...

  15. Au/Cu2Te/CdTe/CdS/TCO/Glass Solar Cells with CdIn2O4 Obtained by Sol-Gel as TCO

    Directory of Open Access Journals (Sweden)

    J. Márquez Marín

    2014-01-01

    Full Text Available An Au/Cu2Te/CdTe/CdS/TCO/glass heterostructure based superstrate solar cells with 2.5 mm2 of area, where the CdTe layer was prepared by means of closed spaced sublimation (CSS and the CdS by chemical bath, reached an efficiency η value of 12.1%. As transparent conductive oxide (TCO, a thin film of cadmium-indium oxide (CdIn2O4:CIO, obtained by sol-gel technique, was used. A systematic optimization of the thermal activation of the CdTe/CdS/CIO central part of the device with a CdCl2 vapor ambient made the conversion efficiency of the Au/Cu2Te/CdTe/CdS/CIO/glass heterostructure reaches 9.94% for the CdTe layer with thickness of 1.8 μm. This efficiency was reached only through an open circuit voltage VOC optimization. A maximum η of 12.1% was reached with the established procedure of optimization and when the CdTe layer thickness was increased to 3.1 ± 0.05 μm. The substitution of CIO by commercial ITO provoked in the cell a decrease of η from 12.1% to 7.2%, both devices prepared under the same conditions. Starting from these results, we can say that CIO was a better TCO than commercial ITO in our solar cell, with the advantage that CIO was obtained by sol-gel, which is a simple and economical technique.

  16. 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....

  17. Impact of the Cd2+ treatment on the electrical properties of Cu2ZnSnSe4 and Cu(In,Ga)Se-2 solar cells

    OpenAIRE

    Ben Messaoud, Khaled; Buffiere, Marie; Brammertz, Guy; ElAnzeery, Hossam; Oueslati, Souhaib; Hamon, Jonathan; Kniknie, Bas J.; MEURIS, Marc; Amlouk, Mosbah; Poortmans, Jef

    2015-01-01

    The present contribution aims at determining the impact of modifying the properties of the absorber/buffer layer interface on the electrical performance of Cu2ZnSnSe4 (CZTSe) thin-film solar cells, by using a Cd2+ partial electrolyte (Cd PE) treatment of the absorber before the buffer layer deposition. In this work, CZTSe/CdS solar cells with and without Cd PE treatment were compared with their respective Cu(In,Ga)Se-2 (CIGSe)/CdS references. The Cd PE treatment was performed in a chemical ba...

  18. 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...

  19. Magnetic properties of R2Fe14-xMxB, R = Y, Gd, M = Si, Cr, Cu alloys

    International Nuclear Information System (INIS)

    Structural and magnetic properties of R2Fe14-xMxB systems (R = Y, Gd, M = Si, Cr, Cu) are investigated. These compounds crystallize in a tetragonal system at P42/mnm-type for a Si content up to x = 2, Cr content up to x = 3 and for Cu concentration up to x = 1.5. The Curie temperature increases when Fe is substituted by Si and Cu, decreases when Fe is replaced by Cr. The saturation magnetization decreases with increasing content of a M element

  20. Fabrication and mechanical properties of AlCoNiCrFe high-entropy alloy particle reinforced Cu matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jian, E-mail: chenjian@xatu.edu.cn [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Niu, Pengyun; Wei, Ting [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Hao, Liang [College of Architecture and Civil Engineering, Xi' an University of Science and Technology, Xi' an 710054 (China); Liu, Yunzi [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Wang, Xianhui, E-mail: xhwang693@xaut.edu.cn [School of Materials Science and Engineering, Xi' an University of Technology, Xi' an, Shaanxi 710048 (China); Peng, Yuli [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China)

    2015-11-15

    The AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying and the AlCoNiCrFe high-entropy alloy reinforced Cu matrix composites were subsequently fabricated by powder metallurgy. The phase constituents and morphology of the alloying powders were characterized by X-ray diffractometer and scanning electron microscope, the microstructures of the Cu base composites were characterized by scanning electron microscope and transmission electron microscope, and the compression tests were made as well. The results show that the AlCoNiCrFe high-entropy alloy can form after milling for 24 h. During sintering process, no grain growth occurs and no intermetallic phases present in the AlCoNiCrFe high-entropy alloy in the Cu base composite. Compression tests show that the AlCoNiCrFe high-entropy alloy has a better strengthening effect than metallic glasses and the yield strength of the Cu matrix composite reinforced with the AlCoNiCrFe high-entropy alloy is close to the value predicted by the Voigt model based on the equal strain assumption. - Graphical abstract: AlCoNiCrFe HEA has a better strengthening effect than metallic glasses for particulate reinforced metal matrix composites. The yield strength of the Cu base composite reinforced with the AlCoNiCrFe HEA is close to the upper bound calculated by Voigt model. - Highlights: • AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying. • A novel Cu base composite reinforced with AlCoNiCrFe was fabricated. • No grain growth and no intermetallic phase present in AlCoNiCrFe during sintering. • AlCoNiCrFe has a better strengthening effect than metallic glassy in composites.

  1. Fabrication and mechanical properties of AlCoNiCrFe high-entropy alloy particle reinforced Cu matrix composites

    International Nuclear Information System (INIS)

    The AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying and the AlCoNiCrFe high-entropy alloy reinforced Cu matrix composites were subsequently fabricated by powder metallurgy. The phase constituents and morphology of the alloying powders were characterized by X-ray diffractometer and scanning electron microscope, the microstructures of the Cu base composites were characterized by scanning electron microscope and transmission electron microscope, and the compression tests were made as well. The results show that the AlCoNiCrFe high-entropy alloy can form after milling for 24 h. During sintering process, no grain growth occurs and no intermetallic phases present in the AlCoNiCrFe high-entropy alloy in the Cu base composite. Compression tests show that the AlCoNiCrFe high-entropy alloy has a better strengthening effect than metallic glasses and the yield strength of the Cu matrix composite reinforced with the AlCoNiCrFe high-entropy alloy is close to the value predicted by the Voigt model based on the equal strain assumption. - Graphical abstract: AlCoNiCrFe HEA has a better strengthening effect than metallic glasses for particulate reinforced metal matrix composites. The yield strength of the Cu base composite reinforced with the AlCoNiCrFe HEA is close to the upper bound calculated by Voigt model. - Highlights: • AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying. • A novel Cu base composite reinforced with AlCoNiCrFe was fabricated. • No grain growth and no intermetallic phase present in AlCoNiCrFe during sintering. • AlCoNiCrFe has a better strengthening effect than metallic glassy in composites

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

    International Nuclear Information System (INIS)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, C., E-mail: ceaguilar@uach.c [Instituto de Materiales y Procesos Termomecanicos, Facultad de Ciencias de la Ingenieria, Universidad Austral de Chile, General Lagos 2086, Valdivia (Chile); Ordonez, S. [Departamento de Ingenieria Metalurgica, Facultad de Ingenieria, Universidad de Santiago de Chile, Av. L. Bernardo O' Higgins 3363, Santiago (Chile); Guzman, D. [Departamento de Metalurgia, Facultad de Ingenieria, Universidad de Atacama, Av. Copayapu 485, Copiapo (Chile); Rojas, P.A. [Escuela de Ingenieria Mecanica, Facultad de Ingenieria, Pontificia Universidad Catolica de Valparaiso, Av. Los Carrera 01567, Quilpue (Chile)

    2010-08-13

    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.

  4. All Screen-Printed CdS/CuInSe2 Solar Cells

    Science.gov (United States)

    Kuhaimi, S. A. AL; Bahammam, S.

    1990-08-01

    Thick film technology offers advantages of low cost, product amenability and automation. This technology has been successful in the manufacture of solar cells using CdS/CdTe heterojunctions. It enables the use of the same equipment in various processes involved in manufacturing solar cells. In the present work, n-CdS/p-CuInSe2 solar cells are prepared by screen printing and sintering pastes which contain the semiconductors. An efficiency of 8.75% is achieved. Electron affinity difference, saturation current and diode quality factor are measured. They are 0.49 eV, (0.9--1.8)× 10-7 A, 1.5 respectively. Microstructure and electrical properties of sintered CdS films containing 10, 20, 30 and 40 wt% CdCl2 are investigated. Optimum results are obtained for the CdS films containing 10 wt% CdCl2.

  5. First-principles calculations of magnetic properties for CdCrO{sub 2} under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Amari, S., E-mail: siham_amari@yahoo.fr [Laboratoire de Modelisation et de Simulation en Sciences des Materiaux, Departement de Physique Universite Djillali Liabes, Faculte des sciences, Universite Djillali Liabes, BP 89 Sidi Bel Abbes 22000 (Algeria); Mecabih, S.; Abbar, B.; Bouhafs, B. [Laboratoire de Modelisation et de Simulation en Sciences des Materiaux, Departement de Physique Universite Djillali Liabes, Faculte des sciences, Universite Djillali Liabes, BP 89 Sidi Bel Abbes 22000 (Algeria)

    2013-02-15

    By employing the first-principles method of the full potential linear augmented plane waves plus the local orbitals (FP-L/APW+lo) within the generalized gradient approximation for the exchange and correlation potential, the structural, electronic, and magnetic properties of chalcopyrite compound CdCrO{sub 2} are investigated. In order to take into account the strong on-site Coulomb interaction, we also performed the generalized gradient approximation plus the Hubbard correlation terms. We systematically study how the exchange interactions and magnetic moments of CdCrO{sub 2} are affected by the different choice of U as well as the exchange correlation potential. We have also carried out the pressure effect on the magnetic properties. - Highlights: Black-Right-Pointing-Pointer The calculation of the exchange constants. Black-Right-Pointing-Pointer The pressure dependence of the magnetic properties. Black-Right-Pointing-Pointer The exchange correlation potential effect on the magnetic properties.

  6. Effect of Cr on Microstructure and Properties of a Series of AlTiCr x FeCoNiCu High-Entropy Alloys

    Science.gov (United States)

    Li, Anmin; Ma, Ding; Zheng, Qifeng

    2014-04-01

    A series of AlTiCr x FeCoNiCu ( x: molar ratio, x = 0.5, 1.0, 1.5, 2.0, 2.5) high-entropy alloys (HEAs) were prepared by vacuum arc furnace. These alloys consist of α-phase, β-phase, and γ-phase. These phases are solid solutions. The structure of α-phase and γ-phase is face-centered cubic structure and that of β-phase is body-centered cubic (BCC) structure. There are four typical cast organizations in these alloys such as petal organization (α-phase), chrysanthemum organization (α-phase + β-phase), dendrite (β-phase), and inter-dendrite (γ-phase). The solidification mode of these alloys is affected by Chromium. If γ-phase is not considered, AlTiCr0.5FeCoNiCu and AlTiCrFeCoNiCu belong to hypoeutectic alloys; AlTiCr1.5FeCoNiCu, AlTiCr2.0FeCoNiCu, and AlTiCr2.5FeCoNiCu belong to hypereutectic alloys. The cast organizations of these alloys consist of pro-eutectic phase and eutectic structure (α + β). Compact eutectic structure and a certain amount of fine β-phase with uniform distribution are useful to improve the microhardness of the HEAs. More γ-phase and the microstructure with similar volume ratio values of α-phase and β-phase improve the compressive strength and toughness of these alloys. The compressive fracture of the series of AlTiCr x FeCoNiCu HEAs shows brittle characteristics, suggesting that these HEAs are brittle materials.

  7. Light-stimulated carrier dynamics of CuInS2/CdS heterotetrapod nanocrystals

    Science.gov (United States)

    Sakamoto, Masanori; Inoue, Koki; Okano, Makoto; Saruyama, Masaki; Kim, Sungwon; So, Yeong-Gi; Kimoto, Koji; Kanemitsu, Yoshihiko; Teranishi, Toshiharu

    2016-05-01

    We synthesized a heterotetrapod composed of a chalcopyrite(ch)-CuInS2 core and wurtzite(w)-CdS arms and elucidated its optical properties and light-stimulated carrier dynamics using fs-laser flash photolysis. The CuInS2/CdS heterotetrapod possessed quasi-type II band alignment, which caused much longer-lived charge separation than that in the isolated CuInS2 nanocrystal.We synthesized a heterotetrapod composed of a chalcopyrite(ch)-CuInS2 core and wurtzite(w)-CdS arms and elucidated its optical properties and light-stimulated carrier dynamics using fs-laser flash photolysis. The CuInS2/CdS heterotetrapod possessed quasi-type II band alignment, which caused much longer-lived charge separation than that in the isolated CuInS2 nanocrystal. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01097k

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

    Science.gov (United States)

    Nunes, Lidiane Cristina; de Carvalho, Gabriel Gustinelli Arantes; Santos, Dario; Krug, Francisco José

    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- 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- 1 Cd, 2 mg kg- 1 Cr and 15 mg kg- 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.

  9. 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

    . Probably the strain induced by the incoherency between BCC Cr precipitates with the matrix FCC Cu is relaxed by the enrichment of Zr, Si and Fe. Positron lifetime and coincidence Doppler broadening experiments suggest that vacancy-like defects form and associate with Cr atoms around the interfaces between......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....... Further reaging at 600 degrees C caused the clusters to grow to almost spherical (I h) and thick platelets (4 h) Cr precipitates. Zr and impurities of Si and Fe were concentrated around the Cr precipitates, resulting in almost pure Cr cores sandwiched with interface regions enriched with Zr, Si and Fe...

  10. Synthesis, characterization and magnetic properties of nearly monodisperse CuCr2Se4 nanoparticles

    International Nuclear Information System (INIS)

    Nearly monodisperse CuCr2Se4 hexagon-shaped nanoparticles with crystallite sizes from 15.1 to 24.3 nm were synthesized by thermal decomposition of metal chlorides and selenium powder in oleylamine. In addition, the 'flower'-shaped CuCr2Se4 nanoparticles with a crystallite size 19.8 nm were also fabricated under similar conditions using heptanoic acid. Magnetic measurements show that all samples reveal ferromagnetic behavior below 350 K. The 'flower'-shaped nanoparticles have saturation magnetization, coercivity and remanent magnetization higher than the hexagon-shaped nanoparticles. However, the Curie temperature of the 'flower'-shaped nanoparticles (∼380 K) is somewhat lower than in the hexagon-shaped nanoparticles (420-430 K). These phenomena may be associated with the shape and surface anisotropy which would exert a tremendous influence on the particle's magnetic properties.

  11. Creep of Uncoated and Cu-Cr Coated NARloy-Z

    Science.gov (United States)

    Walter, R. J.; Chiang, K. T.

    1998-01-01

    Stress rupture creep tests were performed on uncoated and Cu-30vol%Cr coated NARloy-Z copper alloy specimens exposed to air at 482 C to 704 C. The results showed that creep failure in air of unprotected NARloy-Z was precipitated by brittle intergranular surface cracking produced by strain assisted grain boundary oxidation (SAGBO) which in turn caused early onset of tertiary creep. For the protected specimens, the Cu-Cr coating remained adherent throughout the tests and was effective in slowing down the rate of oxygen absorption, particularly at the higher temperatures, by formation of a continuous chromium oxide scale. As the result of reducing oxygen ingress, the coating prevented SAGBO initiated early creep failure, extended creep deformation and increased the creep rupture life of NARloy-Z over the entire 482 C to 704 C test temperature range.

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

    International Nuclear Information System (INIS)

    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)

  13. Biosorption of Heavy Metal Cu2+ and Cr2+ in Textile Wastewater by Using Immobilized Algae

    OpenAIRE

    Hadiyanto; Aris Bagus Pradana; Luqman Buchori; C Sri Budiyati

    2014-01-01

    The objective of this research was to utilize microalgae Chlorella sp. and Spirulina sp., as biosorption agents for heavy metals removal available in textile waste water. The biosorption of Cu and Cr ions from textile waste water solutions by immobilized algae (Chlorella and Spirulina) were tested under laboratory conditions as a function of waste concentration (15-50% dilution) and ratio of bead and waste water (1:1-1:3). Experimental results showed that the Langmuir adsorption models were s...

  14. Nanoindentation deformation of a bi-phase AlCrCuFeNi2 alloy

    International Nuclear Information System (INIS)

    Highlights: • The AlCrCuFeNi2 HEA consisted of BCC solid solution and FCC solid solution. • The indentation hardness of the BCC crystals is larger than the FCC crystals. • The contact modulus of the FCC crystals is larger than the BCC crystals. - Abstract: High-entropy alloys (HEA) are multicomponent alloys with lattice structures, which have unique mechanical properties. Using X-ray diffraction, the structure of as cast AlCrCuFeNi2 HEA was characterized. The AlCrCuFeNi2 HEA consisted of body centered-cubic (BCC) solid solution and face centered-cubic (FCC) solid solution. Nanoindentation was used to characterize the indentation deformation of the FCC and BCC crystals in the AlCrCuFeNi2 HEA. Both the indentation hardness and the contact modulus of the FCC and BCC crystals decreased slightly with the increase in the indentation load and became constant for large indentation loads. For the indentation load larger than 500 μN, the contact modulus and the indentation hardness of the BCC crystals are 146 and 4.6 GPa, respectively, and the contact modulus and the indentation hardness of the FCC crystals are 207 and 2.8 GPa, respectively. The plastic energy dissipated in the nanoindentation increased with the indentation load and was proportional to the 1.77 and 1.88 power of the indentation load for the FCC and BCC crystals, respectively. The ratio of the dissipated plastic energy to the total energy in the indentations was a linear function of the ratio of the residual indentation depth to the corresponding maximum indentation depth. The slope of the energy ratio verse the indentation depth ratio for the BCC crystals is larger than that for the FCC crystals

  15. Electrokinetic Treatment of Cr-, Cu-, and Zn-Contaminated Sediment: Cathode Modification

    OpenAIRE

    Rajić, Ljiljana; Dalmacija, Božo; Perović, Svetlana Ugarčina; Krčmar, Dejan; Rončević, Srđan; Tomašević, Dragana

    2013-01-01

    Enhanced electrokinetic (EK) removal of Cr, Cu, and Zn from sediment by using original and modified integrated ion exchange (IIX™) cathodes was investigated. IIX cathode design and EK device process modifications were made to improve performance: separation of IIX cathode components (IIXS), combination of modified IIX cathode with pulsed electric field (IIXSP), and separation of IIX cathode components with addition of an anion exchange resin compartment (IIXA). After using the IIXSP, overall ...

  16. Qualification of CuCr1Zr for the SLM Process

    OpenAIRE

    Uhlmann, E.; A. E. Tekkaya; Kashevko, V.; Gies, S; Reimann, R; John, P.

    2016-01-01

    Working coils for electromagnetic forming processes need to comply with a wide list of requirements such as durability, efficiency and a tailored pressure distribution. Due to its unique combination of high strength and high electrical conductivity CuCr1Zr meets these requirements and is a common material for coil turns. In combination with conventional coil production processes like winding or waterjet cutting the use of this material is state of the art. A promising approach ...

  17. 基于GSH-CdTe/CdS量子点的荧光变化研究hsDNA与盐酸洛美沙星-Cu(Ⅱ)配合物的相互作用%Interaction of Herring Sperm DNA with Lomefloxacin Hydrochloride-Cu(Ⅱ) Based on Changes in the Fluorescence Intensity of GSH-CdTe/CdS Quantum Dots

    Institute of Scientific and Technical Information of China (English)

    沈益忠; 刘绍璞; 殷鹏飞; 何佑秋

    2013-01-01

    Glutathione (GSH)-capped CdTe/CdS quantum dots(GSH-CdTe/CdS QDs) were synthesized in aqueous solution.The particle sizes and morphological characteristics of GSH-CdTe/CdS QDs were investigated by transmission electron microscopy(TEM).The results exhibits that the particle size of as-prepared QDs has a narrow size distribution and good dispersivity.In Tris-HCl buffer medium (pH =7.6),lomefloxacin hydrochloride-Cu (Ⅱ) coordination compound(LMFH-Cu2+) was adsorbed to the surfaces of GSH-CdTe/CdS QDs through electrostatic attraction and formed ground state complex,which resulted in the quenching of the fluorescence of GSH-CdTe/CdS QDs.Adding herring sperm DNA (hsDNA) to GSH-CdTe/CdS QDs-LMFH-Cu(Ⅱ) system led to the fluorescence intensity of GSH-CdTe/CdS QDs recover,which can be explained by that the addition of hsDNA to the system induced LMFH-Cu(Ⅱ) to dissociate from the surface of GSH-CdTe/CdS QDs and embed into its double helix structure.According to the fluorescence quenching and restoration for GSH-CdTe/CdS QDs,fluorescence reversible control of GSH-CdTe/CdS QDs was realized.Compared with the interaction between GSH-CdTe/CdS QDs and LMFH,the interaction of GSH-CdTe/CdS QDs-LMFH-Cu (Ⅱ)-hsDNA was studied by fluorescence (FL),resonance Rayleigh scattering(RRS) and ultraviolet-visible absorption (UV-Vis) spectra.Meanwhile,the interaction mechanism was discussed and corresponding model of interaction was built.%采用水相法合成了谷胱甘肽(GSH)修饰的CdTe/CdS量子点(GSH-CdTe/CdS QDs).透射电子显微镜表征结果表明,GSH-CdTe/CdS QDs的粒径分布均匀,分散性好.在Tris-HCl(pH=7.6)缓冲液中,由于静电引力作用,带正电的盐酸洛美沙星(LMFH)-Cu(Ⅱ)配合物[LMFH-Cu(Ⅱ)]吸附到带负电的GSH-CdTe/CdSQDs表面形成基态复合物,导致GSH-CdTe/CdS QDs的荧光猝灭.随后,向GSH-CdTe/CdS QDs-LMFH-Ca(Ⅱ)配合物体系中加入鲱鱼精DNA(hsDNA),hsDNA可诱导LMFH-Cu(Ⅱ)配合物从GSH-CdTe/CdS QDs表面脱落而嵌

  18. 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;

    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......) bearing CR1, however, markedly reduced both C3-fragment deposition and MAC formation. Our data suggest that C3-fragment deposition and MAC formation on B lymphocytes in vivo may involve both AP and classical pathway activation, with CR1 contributing significantly to the latter. On the other hand, the...

  19. 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 in...

  20. A novel method for amino starch preparation and its adsorption for Cu(II) and Cr(VI)

    International Nuclear Information System (INIS)

    A novel method was proposed to prepare amino starch by reacting ethylenediamine with previously synthesized dialdehyde starch. Different factors affecting the preparation, i.e., ethylenediamine concentration, ethylenediamine:dialdehyde starch molar ratio, pH, duration and temperature have been studied. The modified starch was characterized by IR spectroscopy, elemental analysis, X-ray diffraction and differential scanning calorimetry. The amino starch derivatives were evaluated as adsorbents. The adsorption activity for heavy metals such as Cu(II) and Cr(VI) by crosslinked amino starch was studied in terms of adsorption amount, kinetics and isotherm; and adsorbent reuse were also studied. Adsorption processes for Cu(II) and Cr(VI) on crosslinked amino starch fit a Langmuir isotherm, and adsorption for Cu(II) and Cr(VI) from aqueous solution was endothermic reactions. Crosslinked amino starch was very effective for the adsorption of Cu(II) and Cr(VI), and efficient in capacity, recycled.

  1. Radiation induced decontamination of Cr(Ⅵ), Cu(Ⅱ) and phenol in some tannery effluents

    Institute of Scientific and Technical Information of China (English)

    Hasan M.KHAN; Abdul MAHMOOD

    2007-01-01

    Industrialization has led to a number of environmental problems, such as release of toxic metals and other toxic organic and inorganic compounds to the environment. Among all, the rapid expansion of leather related industries in Pakistan have resulted in considerable environmental problems and effluents from processing of both domestic and imported hides and skins have increased pollution to alarming levels. Some tannery effluents of Peshawar area investigated in the present study showed high concentrations of Cr(Ⅵ) (2.7-12.6 mg/L), Cu(Ⅱ) (2.6-11.4 mg/L) and phenol (0.1-4.2 mg/L). These contaminants are very toxic and must be removed from effluents before releasing into water bodies. A new technique of gamma irradiation has been investigated to decrease the load of COD and concentrations of Cr(Ⅵ), Cu(Ⅱ) and phenol associated with tannery effluents to the permitted values. It was observed that concentration of Cr(Ⅵ) in the effluents can be brought to the permitted level by applying radiation dose of 3 kGy. A radiation dose of 2.5 kGy was required to remove more than 95% of Cu(Ⅱ) and 100 % degradation of phenol in tannery effluents could be achieved by only one kGy of radiation dose.

  2. Biosorption of Heavy Metal Cu2+ and Cr2+ in Textile Wastewater by Using Immobilized Algae

    Directory of Open Access Journals (Sweden)

    Hadiyanto

    2014-05-01

    Full Text Available The objective of this research was to utilize microalgae Chlorella sp. and Spirulina sp., as biosorption agents for heavy metals removal available in textile waste water. The biosorption of Cu and Cr ions from textile waste water solutions by immobilized algae (Chlorella and Spirulina were tested under laboratory conditions as a function of waste concentration (15-50% dilution and ratio of bead and waste water (1:1-1:3. Experimental results showed that the Langmuir adsorption models were suitable for describing the short-term biosorption of by all algal species. The best ratio of bead: wastewater (v/v for removal heavy metal in textile wastewater was 1:3. The maximum Cu removed from the waste was 89% while Cr was removed with 90% by using Chlorella sp. The algae Spirulina showed a higher removal capacity of 90%. The maximum absorption capacity of Cu was achieved at 16.2 and 13.6 mg/g by using Chlorella and Spirulina, respectively, while the maximum sorption capacity for Cr was achieved at 1.95 and 1.45 mg/g for algae Chlorella and Spirulina, respectively.

  3. Radiation induced decontamination of Cr(VI), Cu(II) and phenol in some tannery effluents

    International Nuclear Information System (INIS)

    Industrialization has led to a number of environmental problems, such as release of toxic metals and other toxic organic and inorganic compounds to the environment. Among all, the rapid expansion of leather related industries in Pakistan have resulted in considerable environmental problems and effluents from processing of both domestic and imported hides and skins have increased pollution to alarming levels. Some tannery effluents of Peshawar area investigated in the present study showed high concentrations of Cr(VI) (2.7-12.6 mg/L), Cu(II) (2.6-11.4 mg/L) and phenol (0.1-4.2 mg/L). These contaminants are very toxic and must be removed from effluents before releasing into water bodies. A new technique of gamma irradiation has been investigated to decrease the load of COD and concentrations of Cr(VI), Cu(II) and phenol associated with tannery effluents to the permitted values. It was observed that concentration of Cr(VI) in the effluents can be brought to the permitted level by applying radiation dose of 3 kGy. A radiation dose of 2.5 kGy was required to remove more than 95% of Cu(II) and 100 % degradation of phenol in tannery effluents could be achieved by only one kGy of radiation dose. (authors)

  4. Role of polycrystallinity in CdTe and CuInSe sub 2 photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Sites, J.R. (Colorado State Univ., Fort Collins, CO (United States))

    1991-01-01

    The polycrystalline nature of thin-film CdTe and CuInSe{sub 2} solar cells continues to be a major factor in several individual losses that limit overall cell efficiency. This report describes progress in the quantitative separation of these losses, including both measurement and analysis procedures. It also applies these techniques to several individual cells to help document the overall progress with CdTe and CuInSe{sub 2} cells. Notably, CdTe cells from Photon Energy have reduced window photocurrent losses to 1 mA/Cm{sup 2}; those from the University of South Florida have achieved a maximum power voltage of 693 mV; and CuInSe{sub 2} cells from International Solar Electric Technology have shown a hole density as high as 7 {times} 10{sup 16} cm{sup {minus}3}, implying a significant reduction in compensation. 9 refs.

  5. 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.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    We have studied the magnetic properties of two amorphous alloy ribbons Fe72Cr6Si4Nb5B12Ag1 (FCSNB-Ag) and Fe72Cr6Si4Nb5B12Cu1 (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 (TC ) 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.

  8. Short-range Ferromagnetism in Alloy Ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

    DEFF Research Database (Denmark)

    Thanh, P. Q.; Hoa, N. Q.; Chau, N.;

    2014-01-01

    We have studied the magnetic properties of two amorphous alloy ribbons Fe72Cr6Si4Nb5B12Ag1 (FCSNB-Ag) and Fe72Cr6Si4Nb5B12Cu1 (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 (TC) 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 beta = 0.369 +/- 0.005, gamma = 1.359 +/- 0.005 and delta = 4.7 +/- 0.1 for FCSNB-Ag, and beta = 0.376 +/- 0.002, gamma = 1.315 +/- 0.006 and delta = 4.5 +/- 0.1 for FCSNB-Cu. Compared with the values from theoretical models, these values are close to those expected for the 3D...

  9. An ab initio study on electronic and magnetic properties of Cr, V doped Cd and Zn nitrides for spintronic applications

    Science.gov (United States)

    Sirajuddeen, M. Mohamed Sheik; Banu, I. B. Shameem

    2016-05-01

    The half-metallic ferromagnetic property of Cr, V doped CdN and ZnN has been investigated by the electronic band structure calculations using Full Potential Linearized Augmented Plane Wave (FP-LAPW) method. The host compounds of CdN and ZnN were doped with Cr and V in the concentration of 37.5% to replace Cd and Zn atoms. The compounds CdN and ZnN doped with Cr are found to exhibit half-metallic ferromagnetism and the results are compared in GGA and GGA+U (Hubbard) method. In this present work, electronic band structure, density of states, magnetic properties and spin polarization were studied. The p-d hybridization in the doped transition metal-d bands and N-p bands that causes exchange splitting was discussed to bring out the differences in the half-metallic character of the doped compounds. The degree of half-metallic nature in terms of spin polarizations has been predicted for Cr-doped CdN and ZnN. The calculated magnetic moments for the doped compounds are found to increase with the increase in Hubbard potential U for Cr-doped compounds. The Cr-doped CdN and ZnN are found to exhibit direct band gap in spin down direction.

  10. Determination of Cr and Cd concentration adsorbed by chicken feathers; Determinacion de concentracion de Cr y Cd adsorbido por plumas de pollo

    Energy Technology Data Exchange (ETDEWEB)

    Lopez M, A.; Cuapio O, L.A.; Cardenas P, S.; Balcazar, M. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico); Jauregui, V.; Bonilla P, A. [ITA, Aguascalientes (Mexico)

    2008-07-01

    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)

  11. Mid-twentieth century increases in anthropogenic Pb, Cd and Cu in central Asia set in hemispheric perspective using Tien Shan ice core

    Science.gov (United States)

    Grigholm, B.; Mayewski, P. A.; Aizen, V.; Kreutz, K.; Wake, C. P.; Aizen, E.; Kang, S.; Maasch, K. A.; Handley, M. J.; Sneed, S. B.

    2016-04-01

    High-resolution major and trace element (Al, As, Ca, Cd, Co, Cr, Cu, Fe, Li, Mn, Na, Pb, S, Ti, and V) ice core records from Inilchek glacier (5120 m above sea level) on the northwestern margin of the Tibetan Plateau provide the first multi-decadal ice core record spanning the period 1908-1995 AD in central Tien Shan. The trace element records reveal pronounced temporal baseline trends and concentration maxima characteristic of post-1950 anthropogenic emissions. Examination of Pb, Cd and Cu concentrations, along with non-crustal calculation estimates (i.e. excess (ex) and enrichment factor (EF)), reveal that discernable anthropogenic inputs began during the 1950s and rapidly increased to the late-1970s and early 1980s, by factors up to of 5, 6 and 3, respectively, relative to a 1910-1950 means. Pb, Cd and Cu concentrations between the 1950s-1980s are reflective of large-scale Soviet industrial and agricultural development, including the growth of production and/or consumption of the non-ferrous metals, coal and phosphate fertilizers. NOAA HYSPLIT back-trajectory frequency analysis suggests pollutant sources originating primarily from southern Kazakhstan (e.g. Shymkent and Balkhash) and the Fergana Valley (located in Kazakhstan, Uzbekistan and Kyrgyzstan). Inilchek ice core Pb, Cd and Cu reveals declines during the 1980s concurrent with Soviet economic declines, however, due to the rapid industrial and agricultural growth of western China, Pb, Cd and Cu trends increase during the 1990s reflecting a transition from primarily central Asian sources to emission sources from western China (e.g. Xinjiang Province).

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

    Science.gov (United States)

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

    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, Cr2O3, CrO2, WO3, Cu2O 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 43.32MPa, which was lower than that of the CoCrW group of 47.65MPa. 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. PMID:27040193

  13. Solvothermal synthesis of CdO and CuO nanocrystals

    OpenAIRE

    Ghosh, Moumita; Rao, CNR

    2004-01-01

    Nanocrystals of CdO have been obtained by the decomposition of the cupferron complex in the presence of tri-n-octylphosphine oxide (TOPO)under solvothermal conditions. The precursor:TOPO ratio plays an important role in determining the size of the nanocrystals. The nanocrystals have been characterized by electron microscopy, absorption spectroscopy and fluorescence spectroscopy, besides X-ray diffraction.The CdO nanocrystals are single crystalline and show evidence for quantum confinement. Cu...

  14. Correlation patterns of Ti, V, Cr, As, Cd, Sb and Pb in Bavarian mosses Hypnum cupressiforme

    International Nuclear Information System (INIS)

    Since 1981, the Bavarian State Office for Environmental Protection has been operating a biomonitoring network of epiphytic mosses Hypnum cupressiforme which is located on a regular grid with distances 16 km. About 300 moss specimens are collected yearly (since 1991 every second year) at the end of the vegetation period, and the content of trace metals in the dry substance is measured. In order to gain insight on main sources of metal pollution in Bavaria, correlation patterns between the metals Ti, V, Cr, As, Cd, Sb, Hg, and Ph were analyzed. The year-specific correlation coefficients for each pair of metals reveal the following behavior consistently over years: Within each pair out of the metals Ti, V, Cr, and As there is a strong and consistent linear relationship; Hg and Cd do not correlate with any other metal; Pb and Sb show moderate correlations to the rest of the metals except Hg and Cd. Higher-dimensional correlation patterns were studied by means of principal component analysis with varimax rotation. Results are presented for the 1984 and 1995 data with the Hg variable excluded, results from the rest of the years were similar. At least 82% of the variance could be explained by three principal components. The following three factors were extracted by varimax rotation from both data sets: one factor with similar loadings for Ti, V, Cr, and As; one factor loading highly on both Sb and Pb; one factor representing mainly Cd. The spatial distribution of the first factor integrates the common gradient with high values in the North-East of Bavaria, indicating that industrial and domestic lignite combustion in the adjacent regions is an important source of those metals. (author)

  15. ACr{sub 2}O{sub 4} /SiO{sub 2} (A = Zn, Cu, Cd) nanocomposites, their preparation and physical properties

    Energy Technology Data Exchange (ETDEWEB)

    Holec, Petr; Plocek, Jiri; Nemec, Ivan [Institute of Inorganic Chemistry, Academy of Sciences of the CR, 250 68 - Rez (Czech Republic); Vejpravova, Jana Poltierova [Charles University Prague, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 - Prague 2 (Czech Republic); Kitazawa, Hideaki [National Institute for Material, Quantum Beam Center, Neutron Scattering Group, 1-2-2 Sengen, Tsukuba-shi, Ibaraki 305-0047 (Japan); Niznansky, Daniel, E-mail: holec@iic.cas.cz [Charles University Prague, Faculty of Sciences, Department of Inorganic Chemistry, Hlavova 2, 121 16 - Prague 2 (Czech Republic)

    2011-10-29

    This article presents preparation and characterization of zinc, copper and cadmium chromites nanocrystals embedded in a silica matrix. The ZnCr{sub 2}O{sub 4}/SiO{sub 2}, CuCr{sub 2}O{sub 4}/SiO{sub 2} and CdCr{sub 2}O{sub 4}/SiO{sub 2} samples were prepared by a conventional sol-gel method using HNO{sub 3} as an acid catalyst, formamide as a modifier, methanol as a solvent and TEOS. Final heat treatment of the nanocomposites was carried out at temperatures in the range of 900 - 1100 deg. C. The resulting samples were characterized by X-ray diffraction, High Resolution Transmission Electron Microscopy, and magnetic measurements.

  16. Production and characterization of Cu/sub 2/S obtained by dipping from CdS chemically sprayed. Study of heat treatments of Cu/sub 2/S/CdS sprayed solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Marjan, M.

    1980-07-01

    The solar cell comprises a pyrex plate covered with a transparent electrode a layer of CdS + Al/sub 2/O/sub 3/ and a layer of CdS obtained by chemical spraying Cu/sub 2/S is obtained by treatment of CdS with a hot solution of CuCl(backwall structure). A p-n junction is obtained between CdS and Cusub(x)S. Thickness and stoichiometry of Cusub(x)S are studied. Photoelectrical properties are improved by annealing. Optical properties and structure of CuS are examined.

  17. Influence of Cd impurity on the electronic properties of CuAlO2 delafossite: first-principles calculations

    International Nuclear Information System (INIS)

    We report on first-principles band-structure calculations of the semiconducting CuAlO2 delafossite compound in the pure form and also with Cd impurity occupying either a Cu or Al position. The computational tool was a full-potential linear augmented plane-wave method, with the generalized gradient approximation accounting for the exchange and correlation effects. The changes caused by the presence of Cd are studied by the analysis of the electronic structure and the electric field gradient (EFG) in both Cd-doped and pure CuAlO2 systems. Good agreement between the calculated and measured EFGs at Cd substituting for Cu or Al atoms in CuAlO2 indicates that the calculations were able to correctly describe the ground state of the system containing the impurity. It is shown that a specific hybridization scheme, involving Cu (and Cd) s and dz2 orbitals and neighbouring O pz orbitals, takes place at the Cu sites in CuAlO2 as proposed earlier. The results of the calculations indicate that the Cd-doped system changes its electrical properties when Cd replaces Cu atoms (producing an n-type semiconductor), but not when it substitutes for Al atoms. (author)

  18. CdS nanowires decorated with Cu2O nanospheres: Synthesis, formation process and enhanced photoactivity and stability

    International Nuclear Information System (INIS)

    Highlights: • Novel CdS/Cu2O heterostructural composites were synthesized by a two-step chemical method. • A formation process of CdS/Cu2O heterostructural composites. • The CdS/Cu2O heterostructural composites were found to have superior photocatalytic performance and stability. - Abstract: CdS/Cu2O heterostructural materials were successfully synthesized by a solvent-thermal process followed by a chemical bath deposition process. Structures and morphologies of the obtained CdS/Cu2O composites were characterized by XRD, SEM, and TEM; the experimental results indicate that the surface of CdS nanowires (NWs) is decorated with spherical Cu2O whose diameter ranges from 100 to 200 nm. Through crystal shape-evolution, the formation process of these hierarchical nanostructures was rationally proposed. Briefly, in the chemical bath deposition process, Cu(OH)2 colloids generate firstly, and then the colloids transform into nanobelts after adding ascorbic acid (AA). With the reaction time further increasing, nanobelts aggregate together to form the hierarchical nanospheres on the surface of CdS NWs. The photoactivity of CdS/Cu2O composite for methyl orange (MO) photodegradation was investigated in detail. The obtained high photocatalytic efficiency can be attributed to the heterojunction structure, which results in the efficient separation of photo-generated electrons and holes

  19. Microstructure and solidification behavior of multicomponent CoCrCu{sub x}FeMoNi high-entropy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wu, P.H. [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Liu, N., E-mail: lnlynn@126.com [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Yang, W. [School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang, Jiangxi 330063 (China); Zhu, Z.X. [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Lu, Y.P. [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Wang, X.J. [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China)

    2015-08-26

    (Fe, Co, Ni) rich dendrites nucleate primarily in CoCrFeMoNi and CoCrCu{sub 0.1}FeMoNi alloys, followed by peritetic and eutectic reactions. The quasi-peritectic reaction occurs between the primary Mo-rich dendrites and liquids in the CoCrCu{sub 0.3}FeMoNi melts, and transfers to a eutectic coupled-growth at the edge of the quasi-peritectic structure. Subsequently, eutectic reaction happens in the remnant liquids. Liquid-phase separations have occurred in CoCrCu{sub x}FeMoNi alloys when x≥0.5. Meanwhile, some nanoscale precipitates are obtained in the Cu-rich region. Two crystal structures, FCC and BCC, are identified in CoCrCu{sub x}FeMoNi high entropy alloys. Amazingly, a pretty high plastic strain (51.6%) is achieved in CoCrCu{sub 0.1}FeMoNi alloy when the compressive strength reaches to 3012 Mpa. With the increase of Cu content, atomic size difference (ΔR) and electro-negativity difference (ΔX) decrease while valence electron concentration (VEC), mixing enthalpy (ΔH) and mixing entropy (ΔS) increase. Consequently, the valence electron concentration (VEC) values range for the formation of mixture of FCC and BCC structures can be enlarged to 6.87–8.35 based on the study of this paper. It is the positive enthalpies of mixing that causes the liquid-phase separation in CoCrCu{sub x}FeMoNi high entropy alloys.

  20. Evaluation of tungsten coatings on CuCrZr and W/Cu FGM under high heat flux and HT-7 limiter plasma irradiation

    International Nuclear Information System (INIS)

    VPS-W coatings on CuCrZr with W/Cu interlayer and powder metallurgic W/Cu functionally graded material (FGM) were tested under high heat flux with active cooling and plasma irradiation in the HT-7 device. Results showed that after 10 MW/m2 thermal shock experiment, exfoliation and crack appeared, however, the interface was not damaged except a few pores. VPS-W can withstand 150 cycles for 100s pulses under 6 MW/m2. After plasma irradiation, tungsten carbide and tungsten oxide were observed by XPS analysis. Bubbles were observed on the surface of W/Cu FGM. These indicated that VPS-W coatings on CuCrZr with W/Cu interlayer have good thermal performance, and W/Cu interlayer was a better alternative compliant layer which can realize reliable W/CuCrZr joint, and the pore microstructure of VPS-W coating is helpful to inhibit the bubble formation

  1. 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.

  2. Ectomycorrhizal Fungus-Induced Changes of Cu and Cd speciation in the rhizosphere of Chinese Pine Seedlings

    Institute of Scientific and Technical Information of China (English)

    HUANG Yi; LI Ting; HUANG Zhi-Ji; FEI Ying-Heng

    2008-01-01

    To understand the role of ectomycorrhizas in improving the tolerance of its host to excessive heavy metals in soil, this study was conducted to exam the patterns of four fractions (the exchangeable, the carbonate-bound, the Fe-Mn oxide-bound and the organically bound) of both Cu and Cd in the rhizosphere of Chinese pine (Pinus tabulaeformis) seedlings grown in excessive Cu and Cd environment. The results showed that the speciation of Cu and Cd in the rhizosphere was significantly influenced by inoculation of ectomycorrhizal fungus Boletus edulis. Compared to the rhizosphere, the content of exchangeable Cu slightly decreased in the mycorrhizosphere of the seedlings grown in 166 and 400 mg kg-1Cu contaminated soil, whereas the exchangeable Cd in the mycorrhizosphere decreased remarkably to only 33% and to 60% that of the rhizosphcre at 0.75 and 1.50 mg kg-1 Cd levels, respectively. These indicate the potential capacity of mycorrhizas to alleviate the damage of heavy metals to the host plants by reducing the bioavailability of heavy metals in soil. Distribution of the 4 tested fractions of Cu and Cd at different contamination levels showed that there was a strong tendency of changing from loosely associatcd fractions to strongly associated fractions in the mycorrhizosphere. The most stable Cd fraction, organically bound Cd, was significantly larger in the mycorrhizosphere than in the rhizosphere at different Cd contamination levels. This phenomenon was also observed for Cu but the difference was not statistically significant.

  3. A facile synthesis and spectral characterization of Cu2+ doped CdO/ZnS nanocomposite

    International Nuclear Information System (INIS)

    A facile two-step method is demonstrated for the preparation of Cu2+ 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 Cu2+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 Cu2+ ions and conductive electrons. - Graphical abstract: M–H curve of Cu2+ doped CdO–ZnS nanocomposites. The magnetic properties of Cu2+ 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 Cu2+ 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 Cu2+ 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 15.8×10−3 and 1.43×10−3 emu/g respectively. The ferromagnetism observed in the prepared material is not commencing with other impurities but expected to be intrinsic. - Highlights: • Cu2+ doped Cd

  4. 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.

  5. Spin-induced symmetry breaking in orbitally ordered NiCr2O4 and CuCr2O4

    Science.gov (United States)

    Suchomel, Matthew R.; Shoemaker, Daniel P.; Ribaud, Lynn; Kemei, Moureen C.; Seshadri, Ram

    2012-08-01

    At room temperature, the normal oxide spinels NiCr2O4 and CuCr2O4 are tetragonally distorted and crystallize in the I41/amd space group due to cooperative Jahn-Teller ordering driven by the orbital degeneracy of tetrahedral Ni2+ (t24) and Cu2+ (t25). Upon cooling, these compounds undergo magnetic ordering transitions; interactions are somewhat frustrated for NiCr2O4 but not for CuCr2O4. We employ variable-temperature high-resolution synchrotron x-ray powder diffraction to establish that at the magnetic ordering temperatures there are further structural changes, which result in both compounds distorting to an orthorhombic structure consistent with the Fddd space group. NiCr2O4 exhibits additional distortion, likely within the same space group, at a yet-lower transition temperature of T=30 K. The tetragonal to orthorhombic structural transition in these compounds appears to primarily involve changes in NiO4 and CuO4 tetrahedra.

  6. 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...... 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...

  7. Biosorption of Cr (VI), Cr (III), Pb (II) and Cd (II) from aqueous solutions by Sargassum wightii and Caulerpa racemosa algal biomass

    Science.gov (United States)

    Tamilselvan, Narayanaswamy; Saurav, Kumar; Kannabiran, Krishnan

    2012-03-01

    Heavy metal pollution is one of the most important environmental problems today. Biosorption is an innovative technology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemical pathways of uptake. Even though several physical and chemical methods are available for removal of heavy metals, currently many biological materials such as bacteria, algae, yeasts and fungi have been widely used due to their good performance, low cost and large quantity of availability. The aim of the present study is to explore the biosorption of toxic heavy metals, Cr(VI), Cr(III), Pb(II) and Cd(II) by algal biomass obtained from algae Sargassum wightii (brown) and Caulerpa racemosa (green). Biosorption of algal biomass was found to be biomass concentration- and pH-dependent, while the maximal biosorption was found at pH 5.0 and with the metal concentration of 100 mg L-1. S. wightii showed the maximal metal biosorption at the biomass concentration of 25 g L-1, followed by C. racemosa with the maximal biosorption at 30 g L-1. S. wightii showed 78% biosorption of Cr(VI), Cr(III), Pb(II) and Cd(II) ions. C. racemosa exhibited 85% biosorption of Cd(II) and Cr(VI), and 50% biosorption of Cr(III) and Pb(II). The results of our study suggest that seaweed biomass can be used efficiently for biosorption of heavy metals.

  8. Magnetoresistive properties of multilayer film systems based on Fe/Cu and Fe/Cr

    Directory of Open Access Journals (Sweden)

    O.V. Synashenko

    2009-01-01

    Full Text Available Magnetoresistive properties of multilayer film systems based on Fe and Cu or Cr were investigated at room temperature. Factors, which influence on the magnetoresistance (MR value change, were studied. In Fe/Cu film system, in which the individuality of separate layers holds, the substrate change from amorphous pyroceramic to monocrystalline Si(111 leads to the MR ratio increase by 35 %, that is connected with magnetic ordering in bottom epitaxial Fe layer. Thermal annealing of the samples to 700 K leads to vanishing of the odd effect in MR in perpendicular geometry and MR increase by two times in parallel geometries. Investigations of [Fe(dFe/Cr(1]10 system showed, that the Fe thickness changes from 0,31 to 1,5 nm, and this leads to the MR magnitude change from 0,03-0,05 % to 1-3 % subject to the different measurement geometries, which is interpreted by Fe granule formation in matrix of solid solution (Fe, Cr.

  9. Influences of Cu or Cd on the neurotoxicity induced by petroleum hydrocarbons in ragworm Perinereis aibuhitensis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qianru; ZHOU Qixing; WANG Jing; SUN Shulan; HUA Tao; REN Liping

    2008-01-01

    The ecotoxicological effects of heavy metals and petroleum hydrocarbons (PHCs) on ragworms are still vague.The relationships between toxicological indices (mortality and acetylcholinesterase (ACHE) activity) and concentrations of toxicants (Cu,Cd,and PHCs)were examined in the estuary keystone species Perinereis aibuhitensis in laboratory conditions.The results of single toxicant indicated that three toxicants had potentially physiological toxicity to P.aibuhitensis.The estimated 4-d and 10-d LC50 for Cu,Cd,and PHCs was derived from the relationships between mortality and toxicants concentrations.Notable changes in the morphological signs and symptoms of P.aibuhitensis exposed to PHCs were observed.The ACHE activity of P.aibuhitensis was more sensitive to the toxicity of PHCs than the others.The results of combined toxicants implied that the combined toxicity of Cu or Cd and PHCs to P.aibuhitensis was related to the concentration combination of toxicants.Compared to single PHCs treatment,the addition of Cu or Cd significantly mitigated the neurotoxicity of PHCs to ACHE activity in P.aibuhitensis,which showed an antagonistic effect.

  10. Magnetic and electrical properties of p-type Mn-doped CuCrO{sub 2} semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Li Da; Fang Xiaodong; Dong Weiwei; Deng Zanhong; Tao Ruhua; Zhou Shu; Wang Jinmei; Wang Tao; Zhao Yiping [Key Lab of New Thin Film Solar Cells, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Zhu Xuebin, E-mail: lida@ustc.ed [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2009-03-07

    Mn-doped CuCrO{sub 2} polycrystalline semiconductors were synthesized by the sol-gel method. The valence state of the Mn ions in the CuCr{sub 1-x}Mn{sub x}O{sub 2} samples was identified as 3+ by analysing their lattice parameters, their electrical properties and their x-ray photoelectron spectra. The temperature dependence of the susceptibility of all samples exhibits paramagnetic behaviour at high temperature. For x = 0.20 the samples exhibit a clear ferromagnetic (FM) transition at 120 K. Clear hysteresis loops indicate that FM order exists in the Mn-doped samples at 50 K. All samples behave like semiconductors. The electrical and magnetic properties indicate that the ferromagnetism can be attributed to the double exchange interaction between the Mn{sup 3+} and Cr{sup 3+} in CuCr{sub 1-x}Mn{sub x}O{sub 2} semiconductors.

  11. Magnetic and electrical properties of p-type Mn-doped CuCrO2 semiconductors

    International Nuclear Information System (INIS)

    Mn-doped CuCrO2 polycrystalline semiconductors were synthesized by the sol-gel method. The valence state of the Mn ions in the CuCr1-xMnxO2 samples was identified as 3+ by analysing their lattice parameters, their electrical properties and their x-ray photoelectron spectra. The temperature dependence of the susceptibility of all samples exhibits paramagnetic behaviour at high temperature. For x = 0.20 the samples exhibit a clear ferromagnetic (FM) transition at 120 K. Clear hysteresis loops indicate that FM order exists in the Mn-doped samples at 50 K. All samples behave like semiconductors. The electrical and magnetic properties indicate that the ferromagnetism can be attributed to the double exchange interaction between the Mn3+ and Cr3+ in CuCr1-xMnxO2 semiconductors.

  12. The effect of production conditions on superparamagnetic properties of the FeCrMoCuNbSiB alloys

    International Nuclear Information System (INIS)

    The aim of this investigation was to choose the chemical composition and to determine the heat treatment conditions for the nanocrystalline Fe72.5-xCrxMo1Cu1Nb3Si13.5B9 (x = 4 or 6) and Fe65Cr7Mo1Cu1Nb3Si12B10.5 alloys in order to get the lowest possible temperature of transition (TC) from the ferromagnetic to superparamagnetic state. On the basis of magnetic and Moessbauer measurements it was found that the temperatures of transition from ferromagnetic to superparamagnetic state in Fe66.5Cr6Mo1Cu1Nb3Si13.5B9 and Fe65.5Cr7Mo1Cu1Nb3Si12B10.5 alloys were 450 K and 424 K, respectively. (author)

  13. Compositional Change of the Au-Cu2Te Contact for Thin-Film CdS/CdTe Solar Cells

    Science.gov (United States)

    Uda, Hiroshi; Ikegami, Seiji; Sonomura, Hajimu

    1990-03-01

    The stability of thin-film CdS/CdTe solar cells with evaporated Au-Cu2Te contacts to the CdTe film has been investigated. A decrease in conversion efficiency due to an increase in series resistance was observed in the solar cells stored in air at room temperature for 120 days. The increase in series resistance is caused by an increase in contact resistance resulting from the compositional change in the Au-Cu2Te contact to the CdTe film.

  14. Effect of Grain Position within a Panicle and Variety on As, Cd, Cr, Ni, Pb Concentrations in japonica Rice

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Two japonica rice varieties, a compact panicle (CP) Xiushui 63 and a loose panicle (LP) Xiushui 11 were grown in a slightly contaminated paddy field, to determine the effect of grain positions within a panicle and variety on grain As, Cd, Cr, Ni and Pb concentrations. There wasa significant difference in grain As, Cd, Cr, Ni and Pb concentrations among grain positions, and the extent of the difference was variety- and metal-specific; Xiushui 63 showed greater difference than Xiushui 11, and As, Cd, Cr and Pb being greater than Ni. The top grains (TG) of a panicle had higher As, Cd and Ni concentrations than the middle ones (MG), and the bottom ones (BG) contained the lowest. With regard to Cr and Pb, the case was opposite. Significantly positive correlations were found between grain weight and As, Cd, Ni concentrations, but there was a negative correlation between grain weight and Cr, and Pb concentrations. There was a remarkable variation in grain filling pattern among grains within a panicle, and between Xiushui 63 and Xiushui 11. In comparison with MG and TG, BG had the lowest grain filling rate and grain weight, leading to obvious difference in grain weight among grains within a panicle, and a greater difference for Xiushui 63 than for Xiushui 11. The regression analysis showed that grain As and Cd concentrations were positively correlated with the maximum grain filling rate (GRm),while negatively correlated with the required time for reaching the maximum grain filling rate (Tpoi). Concerning Cr and Pb, the case was just reverse. It is suggested that As and Cd accumulation in grains might be accompanied by the carbohydrate accumulations, while Cr and Pb accumulation displayed a different pattern.

  15. Cu containing CdTe thin films deposited by two sources technique

    International Nuclear Information System (INIS)

    Cadmium Telluride (CdTe) thin films were deposited onto glass substrates by the two-source evaporation technique. Films were heated under vacuum at 500 degree C for 1 hour and dipped in Cu(No/sub 3/)/sub 2/-H/sub 2/O solution at room temperature These films were again heated under vacuum for 1 hour at 500 degree C to obtain maximum Cu diffusion. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), optically by Lambda 900 UV/VIS/NIR spectrophotometer and electrically, i.e. DC electrical resistivity, by the Van der Pauw method at room temperature. The EDX results showed an increase of Cu content in the samples by increasing the immersion time of the CdTe films in the solution. (author)

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

    International Nuclear Information System (INIS)

    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

  17. Effect of the ITER FW Manufacturing Process on the Microstructure and Properties of a CuCrZr Alloy

    Science.gov (United States)

    Liu, Danhua; Wang, Pinghuai; Song, Yi; Li, Qian; Chen, Jiming

    2015-10-01

    The first wall (FW) is one of the core components in ITER. As the heat sink material, the CuCrZr alloy shall be properly jointed with beryllium and stainless steel. At present, the grains of CuCrZr are prone to coarsen seriously in the thermal cycle process of FW manufacturing, which has become a critical issue for ITER parties. To investigate the mirostructure and mechanical properties of the optimized CuCrZr alloy in the first wall fabricating thermal cycle, simulative experiments have been done in this study. The alloy ingot was forged and hot rolled into plates, and then solid solution annealed, cold rolled and aged for strengthening. Several heat treatments were done to the CuCrZr samples, and the changes of microstructure, micro-hardness and tensile strength were investigated. The results indicated that the original elongated grains had changed into equiaxed ones, and the vickers hardness had declined to about 60 after experiencing the process of CuCrZr/316L(N) bi-metallic plate manufacturing, either by hot isostatic pressing at a higher temperature or by explosion welding followed by solution annealing. Joining Be/CuCrZr by hot isostatic pressing acts as an aging process for CuCrZr, so after the simulated heat treatment, the hardness of the alloy increased to about 110 HV and the tensile yield strength at 250°C rose to about 170 MPa. Meanwhile, the average grain size was controlled below 200 μm. supported by the International Nuclear Thermonuclear Experimental Reactor (ITER) Specific Program of China (No. 2014GB126000)

  18. 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. PMID:24600856

  19. Levels Of Heavy Metals (Hg, Pb, Cd, And Cr) In Tissues Of Trachurus Trachurus

    OpenAIRE

    Enkeleda Ozuni; Luljeta Dhaskali; Jetmira Abeshi; Doriana Beqiraj

    2012-01-01

    The study was carried out to monitor the concentration level of mercury, lead, cadmium and chrome in different tissues of Trachurus trachurus (Horse mackerel). The concentration level of heavy metals was measured by using atomic absorption spectrophotometer (AAS). Concentrations of heavy metals in muscle tissue and liver of this animal ranged as follows: Hg 0.032-0.106; Cd nd-0.067 mg/kg wet weight; Pb and Cr resulted always below the detection level (nd) in all tissue samples. According to t...

  20. 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...

  1. Chemical behavior of Cu, Zn, Cd, and Pb in a eutrophic reservoir: speciation and complexation capacity.

    Science.gov (United States)

    Tonietto, Alessandra Emanuele; Lombardi, Ana Teresa; Choueri, Rodrigo Brasil; Vieira, Armando Augusto Henriques

    2015-10-01

    This research aimed at evaluating cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) speciation in water samples as well as determining water quality parameters (alkalinity, chlorophyll a, chloride, conductivity, dissolved organic carbon, dissolved oxygen, inorganic carbon, nitrate, pH, total suspended solids, and water temperature) in a eutrophic reservoir. This was performed through calculation of free metal ions using the chemical equilibrium software MINEQL+ 4.61, determination of labile, dissolved, and total metal concentrations via differential pulse anodic stripping voltammetry, and determination of complexed metal by the difference between the total concentration of dissolved and labile metal. Additionally, ligand complexation capacities (CC), such as the strength of the association of metals-ligands (logK'ML) and ligand concentrations (C L) were calculated via Ruzic's linearization method. Water samples were taken in winter and summer, and the results showed that for total and dissolved metals, Zn > Cu > Pb > Cd concentration. In general, higher concentrations of Cu and Zn remained complexed with the dissolved fraction, while Pb was mostly complexed with particulate materials. Chemical equilibrium modeling (MINEQL+) showed that Zn(2+) and Cd(2+) dominated the labile species, while Cu and Pb were complexed with carbonates. Zinc was a unique metal for which a direct relation between dissolved species with labile and complexed forms was obtained. The CC for ligands indicated a higher C L for Cu, followed by Pb, Zn, and Cd in decreasing amounts. Nevertheless, the strength of the association of all metals and their respective ligands was similar. Factor analysis with principal component analysis as the extraction procedure confirmed seasonal effects on water quality parameters and metal speciation. Total, dissolved, and complexed Cu and total, dissolved, complexed, and labile Pb species were all higher in winter, whereas in summer, Zn was mostly present in the

  2. A facile synthesis and spectral characterization of Cu2+ doped CdO/ZnS nanocomposite

    Science.gov (United States)

    Joyce Stella, R.; Thirumala Rao, G.; Babu, B.; Pushpa Manjari, V.; Reddy, Ch. Venkata; Shim, Jaesool; Ravikumar, R. V. S. S. N.

    2015-06-01

    A facile two-step method is demonstrated for the preparation of Cu2+ 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 Cu2+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 Cu2+ ions and conductive electrons. The magnetic properties of Cu2+ 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 Cu2+ 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 Cu2+ ions) and conductive electrons is the main cause that leads to the ferromagnetism. Coercivity (Hc) of the field is about 98 Oe, saturationmagnetization (Ms) and remnant magnetization (Mr) of present sample is estimated to be 15.8×10-3 and 1.43×10-3 emu/g respectively. The ferromagnetism observed in the prepared material is not commencing with other impurities but expected to be intrinsic.

  3. Overview spectra and axial distribution of spectral line intensities in a high-current vacuum arc with CuCr electrodes

    Science.gov (United States)

    Lisnyak, M.; Pipa, A. V.; Gorchakov, S.; Iseni, S.; Franke, St.; Khapour, A.; Methling, R.; Weltmann, K.-D.

    2015-09-01

    Spectroscopic investigations of free-burning vacuum arcs in diffuse mode with CuCr electrodes are presented. The experimental conditions of the investigated arc correspond to the typical system for vacuum circuit breakers. Spectra of six species Cu I, Cu II, Cu III, Cr I, Cr II, and Cr III have been analyzed in the wavelength range 350-810 nm. The axial intensity distributions were found to be strongly dependent on the ionization stage of radiating species. Emission distributions of Cr II and Cu II can be distinguished as well as the distributions of Cr III and Cu III. Information on the axial distribution was used to identify the spectra and for identification of overlapping spectral lines. The overview spectra and some spectral windows recorded with high resolution are presented. Analysis of axial distributions of emitted light, which originates from different ionization states, is presented and discussed.

  4. Ultrasonic spray-pyrolyzed CuCrO2 thin films

    Science.gov (United States)

    Sánchez-Alarcón, R. I.; Oropeza-Rosario, G.; Gutierrez-Villalobos, A.; Muro-López, M. A.; Martínez-Martínez, R.; Zaleta-Alejandre, E.; Falcony, C.; Alarcón-Flores, G.; Fragoso, R.; Hernández-Silva, O.; Perez-Cappe, E.; Mosqueda Laffita, Yodalgis; Aguilar-Frutis, M.

    2016-05-01

    In this paper the optical, structural and electrical properties of CuCrO2 thin films deposited by ultrasonic spray pyrolysis at temperatures from 400 to 600 °C in steps of 50 °C are presented. Copper and chromium acetylacetonates were chosen as sources of Cu and Cr, respectively, and N,N-dimethylformamide was used as the solvent. X-ray results confirmed that the films as deposited showed the CuCrO2 phase without any post-deposition thermal annealing. The surface morphology was observed to be mirror like, and as the films were deposited at different temperatures, they gradually revealed the presence of small crystallites. The best film’s optical percentage transmission (in the visible region), about 58%, was obtained in films deposited at 450 °C, and the highest band gap energy (3.17 eV) was measured in films deposited at 400 °C. The electrical properties of the films were obtained by the Hall effect. A hole concentration in the range 1019-1021 cm-3, conductivity as high as 35 S cm-1, and mobility lower than 1 cm2 V-1 s-1 were obtained in the films. p-type conductivity was confirmed using the hot point probe arrangement, and the Seebeck coefficient was estimated. The hole conductivity is thought to be due to excess oxygen in the films. Finally, the minimum energy required to transfer carriers from acceptor level to the valence band in the films was estimated by impedance spectroscopy.

  5. A thermomechanical criterion for hot cracking during electron beam welding of CuCrZr alloy

    International Nuclear Information System (INIS)

    Full text of publication follows: Due to its good thermomechanical and thermophysical properties, precipitation hardened CuCrZr alloy is used for structural components in fusion experiments such as Tore Supra, JET, W7X and will find also application in the thermonuclear fusion reactor ITER. In Tore Supra (CEA Cadarache, France) this material is typically used for heat sink structures of plasma facing components. The experience feedback showed that the CuCrZr alloy was very sensitive to the hot tearing phenomenon during electron beam welding, leading to defects in and/or near the melted zone. The objective of the project under consideration is to propose a hot tearing criterion by mean of numerical simulations, in order to define a welding acceptance test which could be applied to the material, delivered from different manufacturers. In order to characterize the hot tearing phenomenon, a laboratory test, inspired by the Shibahara's experiment, is used. An electron beam welding seam is performed on a thin rectangular plate, which is instrumented with thermocouples while a CCD camera allows recording of eventual cracking defects during welding. The image correlation method permits to determine the displacement field in the solidified welding seam as well as in the non melted zone. In order to identify the hot tearing criterion due to the welding process, the stress and strain state in the material during the laboratory test is calculated with a Lagrangian thermomechanical finite element simulation. For high temperatures, the alloy viscosity is taken into account in order to identify an elasto-viscoplastic behaviour law. Thermomechanical experiments are performed with a Gleeble physical simulator. A thermomechanical criterion for the initiation of hot tearing during electron beam welding of a quenched and aged CuCr1Zr alloy (DIN 17672 standard) has been identified. (authors)

  6. Fatigue Property Study of 05Cr17Ni4Cu4Nb Steel Weld Joints%05Cr17Ni4Cu4Nb钢焊接接头的疲劳性能

    Institute of Scientific and Technical Information of China (English)

    刘福广; 李振伟; 冯琳杰; 李太江; 王琦; 王彩侠; 李巍

    2013-01-01

    Fatigue property of 05Cr17Ni4Cu4Nb steel used for last stage rotor blade of steam turbine weld joints was studied by means of four-point-bending fatigue test and S-N curve was obtained, compared with parent material at the same time. Results showed that conditional fatigue limit of o5Cr17Ni4Cu4Nb steel weld joints can reach 90%of parent metal using optimized weld and post weld heat treatment process. SEM observation of fracture surface of fatigue specimen showed that the micro-defect at surface or near surface and microstructure heterogeneity are the main influence factors of 05Cr17Ni4Cu4Nb weld joints fatigue property.%采用四点弯曲疲劳试验方法,研究了05Cr17Ni4Cu4Nb汽轮机低压末级动叶片用钢焊接接头的疲劳性能,绘制了该钢焊接接头的S-N曲线,并与05Cr17Ni4Cu4Nb钢母材进行了对比。研究结果表明,采用优化的焊接、热处理工艺,05Cr17Ni4CuNb钢焊接接头的条件疲劳极限可以达到母材的90%以上。疲劳试样断口的扫描电子显微镜观察发现,焊缝表面或近表面的显微缺陷及接头的组织不均匀性是影响05Cr17Ni4Cu4Nb钢焊接接头接头疲劳性能的主要因素。

  7. The irreversibility line of (Hg, Cr)Sr2CuO4+δ superconductor

    International Nuclear Information System (INIS)

    Superconducting (Hg, Cr)-1201 phase was synthesized with a nominal composition Hg0.7, Cr0.3Sr2CuO4+δ by solid state reaction method in vacuum-sealed quartz-tube. X-ray diffraction (XRD) analysis of the sample showed a tetragonal symmetry with lattice parameters a = 3.842 (2) A and c = 8.641 (5) A. Ac-susceptibility, dc-magnetization, and dc-resistivity measurements indicate a Tc of 60 K. The irreversibility line (IRL) was obtained from the merging point of the zero field cooled (ZFC) and field cooled (FC) magnetization measurements at several applied fields. The fit H =A(1 -T / Tc)n gave a value of 2.55 for the exponent n. (author)

  8. Synthesis protocol and superconducting properties of (Hg,Cr)Sr2CuO4+δ

    International Nuclear Information System (INIS)

    In this paper, we report the study of our results on the synthesis protocol and the superconducting properties of (Hg,Cr)Sr2CuO4+δ. We have used several distinct approaches for the synthesis of good quality (Hg, Cr)/Sr-1201 samples by varying the processing parameters such as starting materials, precursor and annealing treatments as well as the sample container. The (Hg, Cr)/Sr-1201 samples were synthesized in partial vacuum, and systematically characterized by powder XRD, χ-T, dc-electrical-resistance and dc-magnetization measurements. XRD data confirm that they are of tetragonal Hg/Ba-1201 type structure. Good quality (Hg, Cr)/Sr-1201 samples were obtained from the sample prepared using a strontium nitrate source with a maximum Tconset ∼ 60 K, which is higher than the samples prepared using a carbonate source Tconset ∼ 56 K). It is found that Tc is not affected by the subsequent Ar or O2 annealing treatment. Remarkably, the annealed samples show significant improvement in the diamagnetic transition

  9. 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)

    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.)

  10. STUDY ON THE HOT DEFORMATION BEHAVIORS OF Al-Zn-Mg-Cu-Cr ALUMINUM ALLOY

    Institute of Scientific and Technical Information of China (English)

    G.Y. Lin; Z.F. Zhang; H. Zhang; D.S. Peng; J. Zhou

    2008-01-01

    The hot deformation behaviors and mierostructures of Al-Zn-Mg-Cu-Cr aluminum alloy have been studied using thermal simulation test, optical microscopy and transmission electron microscopy. As a result, the true stress versus true strain curves and the microstructures under various deformation conditions are obtained. The microstructures gradually incline to dynamic-recrystallization with the deformation temperature rising and the recrystallization grains refine with the decrease of deformation temperature or with raising the strain rates. The quantitative relationship between the Zener-HoUomon parameter (Z) and average recrystallization grain size in the subsequent heat treatment is set up.

  11. Epitaxial Cu(001) films grown on a Cr/Ag/Fe/GaAs(001) buffer system

    International Nuclear Information System (INIS)

    We present a procedure to prepare single-crystalline, high-purity Cu(001) films (templates) suitable as substrates for subsequent epitaxial thin-film growth. The template films were grown in a dedicated molecular-beam epitaxy system on a Cr/Ag/Fe/GaAs(001) buffer layer system. Low-energy electron diffraction and X-ray diffraction were applied to determine the surface orientation and the epitaxial relationship between all layers of the stack. Post-annealing at moderate temperatures enhances the quality of the film as shown by low-energy electron diffraction and atomic force microscopy. X-ray photoemission and Auger electron spectroscopy confirm that no atoms of the buffer layers diffuse into the Cu film during the initial preparation and the post-annealing treatment. The completed Cu(001) template system can be exposed to air and afterwards refurbished by Ar+-ion bombardment and annealing, enabling the transfer between vacuum systems. The procedure provides suitable conductive thin film templates for studies of epitaxial thin films, e.g. on the magnetic and magnetotransport properties of Co and Ni based films and multilayers. - Highlights: • Preparation of epitaxial Cu(001) template films on an insulating substrate • Characterization of template structure, orientation, cleanness, and roughness • Template films can be exposed to air and refurbished in different vacuum system. • Template films are suitable for further thin film growth at up to 570 K

  12. Preparation and characterization of CuCrO2/TiO2 heterostructure photocatalyst with enhanced photocatalytic activity

    Science.gov (United States)

    Xiong, Dehua; Chang, Haimei; Zhang, Qingqing; Tian, Shouqin; Liu, Baoshun; Zhao, Xiujian

    2015-08-01

    A series of novel p-type CuCrO2/n-type TiO2 heterostructure photocatalysts were fabricated for the first time by depositing CuCrO2 nanoparticles on TiO2 nanorod-array film through a facile spin-coating method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and photocurrent response were employed to characterize the as-synthesized composites. The photocatalytic activity of CuCrO2/TiO2 for degradation of methylene blue (MB) aqueous solution was much higher than pure TiO2, which could be ascribed to the formation of p-n heterojunctions between CuCrO2 nanoparticles and TiO2 nanorods. In particular, the best degradation efficiency of CuCrO2/TiO2 heterojunction was 85.3%, about 1.14 times higher than pure TiO2 (74.6%), which could be attributed to their high separation efficiency of photogenerated electrons and holes. It is expected this strategy of p-n junction for enhancing photocatalytic activity can have considerable impact to promote the development of high efficient photocatalyst and industrial application for degrading pollutant, treating waste water and other environmental protection fields.

  13. Thermal-mechanical analysis on W/CuCrZr plasma facing component with functionally graded material interlayer

    International Nuclear Information System (INIS)

    Thermal-mechanical analysis is performed on W/CuCrZr plasma facing component with functionally graded material (FGM) interlayer under the steady-state heat load of 5 MW/m2 using a finite element method (ANSYS code). The influences of the FGM interlayer on the stress, strain and temperature distribution in the whole component is evaluated and compared to the joint without an interlayer and with OFHC interlayer. It is shown that the inserting of W/CuCrZr FGM interlayer between W and CuCrZr effectively alleviates the thermal stress, whose reduction can reach up to 70% when the W/CuCrZr FGM interlayer thickness exceeds 6 mm. Meanwhile, the optimization of the structure and component distribution for W/CuCrZr FGM interlayer was also carried out. The thermal stress tends to saturate with the layer number exceeding 4. For 6 mm 4-layered FGM interlayer, the preferred component distribution exponent (p) is 1.8.

  14. Phase transition in nonmagnetic Al-doped delafossite oxide CuCrO{sub 2}: Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Z.R.; Qin, M.H., E-mail: qinmh@scnu.edu.cn

    2015-10-09

    In this work, the effects of the lattice defects and random exchange interaction on the phase transition in the classical frustrated spin model (Lin et al., 2014) [14] are investigated by Monte Carlo simulation in order to study the nonmagnetic Al doping effect in CuCrO{sub 2}. It is observed that the long range magnetic order can be significantly suppressed by the lattice defects and random exchange induced by the Al substitution, qualitatively consistent with experimental observation. Thus, both the lattice defects and random exchange are confirmed to be responsible for the variation of the transition temperature of CuCr{sub 1−x}Al{sub x}O{sub 2} with x. - Highlights: • Al doping effect on phase transition in CuCrO{sub 2} is studied by Monte Carlo simulation of a classical Heisenberg model. • Both the lattice defects and random exchange contribute to the variation of the transition temperature of CuCr{sub 1−x}Al{sub x}O{sub 2} with x. • The effect of the lattice defects is proved to be dominant in the Al doping effect in CuCrO{sub 2}.

  15. Control of p-type conduction in Mg doped monophase CuCrO2 thin layers

    Science.gov (United States)

    Chikoidze, E.; Boshta, M.; Gomaa, M.; Tchelidze, T.; Daraselia, D.; Japaridze, D.; Shengelaya, A.; Dumont, Y.; Neumann-Spallart, M.

    2016-05-01

    This work aims to clarify the origin of hole conduction in undoped and Mg-doped CuCrO2 oxide in order to have the possibility of controlling it by corresponding growth parameters. A chemical spray pyrolysis procedure for the deposition of p-type semiconductor thin films is described. The as-deposited films were amorphous. The formation of highly crystalline CuCrO2 and Mg-doped CuCrO2 films with a single phase delafossite structure was realized by annealing between 600 °C and 960 °C in a nitrogen atmosphere. The carrier concentration and the point defects of the samples are calculated by using the developed Kroger method of quasi-chemical reactions. p-type conductivity was predicted and observed in the undoped and Mg doped CuCrO2 sample, and with n ~ 1018 cm‑3 carrier concentrations for 4%Mg doping. The electrical resistivity for a 4% Mg doped sample was 1.4 Ω·cm with a Seebeck coefficient of  +130 μV K‑1 at 40 °C. By electroparamagnetic resonance spectroscopy Cr3+ and Cu2+ related defects were studied.

  16. Cu-Cr-Nb-Zr Alloy for Rocket Engines and Other High-Heat- Flux Applications

    Science.gov (United States)

    Ellis, David L.

    2013-01-01

    Rocket-engine main combustion chamber liners are used to contain the burning of fuel and oxidizer and provide a stream of high-velocity gas for propulsion. The liners in engines such as the Space Shuttle Main Engine are regeneratively cooled by flowing fuel, e.g., cryogenic hydrogen, through cooling channels in the back side of the liner. The heat gained by the liner from the flame and compression of the gas in the throat section is transferred to the fuel by the liner. As a result, the liner must either have a very high thermal conductivity or a very high operating temperature. In addition to the large heat flux (>10 MW/sq m), the liners experience a very large thermal gradient, typically more than 500 C over 1 mm. The gradient produces thermally induced stresses and strains that cause low cycle fatigue (LCF). Typically, a liner will experience a strain differential in excess of 1% between the cooling channel and the hot wall. Each time the engine is fired, the liner undergoes an LCF cycle. The number of cycles can be as few as one for an expendable booster engine, to as many as several thousand for a reusable launch vehicle or reaction control system. Finally, the liners undergo creep and a form of mechanical degradation called thermal ratcheting that results in the bowing out of the cooling channel into the combustion chamber, and eventual failure of the liner. GRCop-84, a Cu-Cr-Nb alloy, is generally recognized as the best liner material available at the time of this reporting. The alloy consists of 14% Cr2Nb precipitates in a pure copper matrix. Through experimental work, it has been established that the Zr will not participate in the formation of Laves phase precipitates with Cr and Nb, but will instead react with Cu to form the desired Cu-Zr compounds. It is believed that significant improvements in the mechanical properties of GRCop-84 will be realized by adding Zr. The innovation is a Cu-Cr-Nb-Zr alloy covering the composition range of 0.8 to 8.1 weight

  17. The use of copper alloy CuCrZr as a structural material for actively cooled plasma facing and in vessel components

    Energy Technology Data Exchange (ETDEWEB)

    Lipa, M. [CEA/Cadarache-DSM/DRFC, F-13108 Saint Paul Lez Durance (France)]. E-mail: manfred.lipa@cea.fr; Durocher, A. [CEA/Cadarache-DSM/DRFC, F-13108 Saint Paul Lez Durance (France); Tivey, R. [ITER Garching Joint Work Site, D-85748 Garching (Germany); Huber, Th. [Plansee AG, A-6600 Reutte (Austria); Schedler, B. [Plansee AG, A-6600 Reutte (Austria); Weigert, J. [PTR Praezisionstechnik GmbH, D-63461 Maintal-Doernigheim (Germany)

    2005-11-15

    This paper presents our experience with precipitation hardened CuCrZr in the fabrication of actively cooled components for Tore Supra (toroidal pump limiter fingers, guard limiter heat sink hollow-profiles, ripple protection tubes, endoscope heads) and JET high heat flux elements for the beam-lines. The supposed interplay phenomenon between CuCrZr procurement, component geometry and welding procedure is discussed. The associated mechanical characterisation of materials from different suppliers and component joinings, focused especially on CuCrZr-CuCrZr fusion weldings using electron beams (EB), is presented.

  18. Phytoremediation of Metal (Pb, Ni, Zn, Cd And Cr Contaminated Soils Using Canna Indica

    Directory of Open Access Journals (Sweden)

    V. Subhashini

    2014-12-01

    Full Text Available Heavy metal pollution has become one of the most serious environmental problems today. Remediation of heavy metal polluted soils is one of the significant topics in environmental restoration. As a plant based technology the success of phytoremediation is inherently dependent upon proper plant selection. The present study is an attempt to test the potential of the native species to remove heavy metals from the soil. A pot experiment was conducted to study the metal accumulation capacity of Canna indica L. Canna indica was known as Indian shot belongs to the family Cannaceae. High biomass herb species was selected to restrict the passage of contaminants into the food chain by selecting non-edible, disease resistant and tolerant plants and have very pleasant flowers. Based on the BCF and TF the plant species was used in Pb, Zn and Cr phytoextraction process and Ni and Cd phytostabilization processes. Finally it was concluded that the species was good accumulator of Pb, Ni, Zn, Cd and Cr.

  19. Thermally-restorable optical degradation and the mechanism of current transport in Cu2S-CdS photovoltaic cells

    Science.gov (United States)

    Fahrenbruch, A. L.; Bube, R. H.

    1974-01-01

    The photovoltaic properties of single-crystal Cu2S-CdS heterojunctions have been investigated as a function of heat treatment by detailed measurements of the dependence of short-circuit current on photon energy, temperature, and the state of optical degradation or enhancement. A coherent picture is formulated for the relationship between enhancement and optical degradation, and their effect on the transport of short-circuit photoexcited current and dark, forward-bias current in the cell. Optical degradation in the Cu2S-CdS cell is shown to be closely identical to optical degradation of lifetime in a homogeneous CdS:Cd:Cu crystal, indicating that the CdS:Cu layer near the junction interface controls carrier transport in the cell. It is proposed that both the photoexcited short-circuit current and the dark, forward-bias current are controlled by a tunneling-recombination process through interface states.

  20. Effect of interfacial reactions on the photoelectrical performance of In(CrOx)/CdTe/ITO heterostructures

    International Nuclear Information System (INIS)

    The effect of interphase interaction of interlinking layers on photoelectric properties of cadmium telluride base polycrystalline photoelectric converters was studied to optimize their production process. It was shown that reduction of the high level of CdTe surface grains moving of space charge range in the base layer from the finely-crystalline defects layer at CdTe/ITO interface and CrOx/CdTe contact substitution for In/CdTe rear contact increased the efficiency of those photoelectric converters up to 6 %

  1. Synthesis and enhanced photocatalytic property of feather-like Cd-doped CuO nanostructures by hydrothermal method

    Science.gov (United States)

    Wang, Yongqian; Jiang, Tingting; Meng, Dawei; Wang, Dagui; Yu, Meihua

    2015-11-01

    Feather-like Cd-doped CuO nanostructures were fabricated by a one-step hydrothermal method. X-ray diffraction pattern (XRD) and field emission scanning electron microscopy (FESEM) demonstrated that Cd2+ entered the crystal lattice of CuO and substituted Cu2+ without destroying crystal structures to form feather-like CuO nanostructures. The optical property of Cd-doped CuO was investigated by using UV-vis spectrophotometer. A slight blue-shift of optical band gap was observed because of quantum confinement effect. The doped samples exhibited obviously higher absorbance in UV light region and better photocatalytic activity for the photodegradation of methyl blue than the pure CuO nanosheets.

  2. Atmospheric deposition of heavy metals (Cu, Zn, Cd and Pb) in Varanasi City, India.

    Science.gov (United States)

    Sharma, Rajesh Kumar; Agrawal, Madhoolika; Marshall, Fiona M

    2008-07-01

    Rapid growth in urbanization and industrialization in developing countries may significantly contribute in heavy metal contamination of vegetables through atmospheric depositions. In the present study, an assessment was made to investigate the spatial and seasonal variations in deposition rates of heavy metals and its contribution to contamination of palak (Beta vulgaris). Samples of bulk atmospheric deposits and Beta vulgaris for analysis of Cu, Zn, Cd and Pb were collected from different sampling locations differing in traffic density and land use patterns. The results showed that the sampling locations situated in industrial or commercial areas with heavy traffic load showed significantly elevated levels of Cu, Zn and Cd deposition rate as compared to those situated in residential areas with low traffic load. The deposition rates of Cu, Zn and Cd were significantly higher in summer and winter as compared to rainy season, however, Pb deposition rate was significantly higher in rainy and summer seasons as compared to winter season. Atmospheric depositions have significantly elevated the levels of heavy metals in B. vulgaris collected during evening as compared to those collected in morning hours. The study further showed that local population has maximum exposure to Cd contamination through consumption of B. vulgaris. The present study clearly points out the urban and industrial activities of a city have potential to elevate the levels of heavy metals in the atmospheric deposits, which may consequently contaminate the food chain and thus posing health risk to the local population. PMID:17879134

  3. Swift heavy ion irradiation effect on Cu-doped CdS nanocrystals embedded in PMMA

    Indian Academy of Sciences (India)

    Shweta Agrawal; Subodh Srivastava; Sumit Kumar; S S Sharma; B Tripathi; M Singh; Y K Vijay

    2009-12-01

    Semiconductor nanocrystals (NCs) have received much interest for their optical and electronic properties. When these NCs dispersed in polymer matrix, brightness of the light emission is enhanced due to their quantum dot size. The CdCuS NCs have been synthesized by chemical route method and then dispersed in PMMA matrix. These nanocomposite polymer films were irradiated by swift heavy ion (SHI) (100 MeV, Si+7 ions beam) at different fluences of 1 × 1010 and 1 × 1012 ions/cm2 and then compared their structural and optical properties by XRD, atomic force microscopy, photoluminescence, and UV-Vis spectroscopy before and after irradiation. The XRD spectra showed a broad hump around 2 ≈ 11.83° due to amorphous PMMA and other peaks corresponding to hexagonal structure of CdS nanocrystals in PMMA matrix. The photoluminescence spectra shows a broad peak at 530 nm corresponding to green emission due to Cu impurities in CdS. The UV-Vis measurement showed red shift in optical absorption and bandgap changed from 4.38–3.60 eV as the irradiation fluency increased with respect to pristine CdCuS nanocomposite polymer film.

  4. Effect of Cd and Sn Addition on the Microstructure and Mechanical Properties of Al-Si-Cu-Mg Cast Alloy

    Institute of Scientific and Technical Information of China (English)

    LI Rong-de; LI Run-xia; YU Li; HU Zhuang-qi

    2004-01-01

    The present work has investigated the effect of trace elements Cd and Sn on the microstructure and mechanical properties of Al-Si-Cu-Mg cast alloy. With the increase of Cd addition the strength of alloy rises at first and then drops. The optimal amount of Cd and Sn addition for Al-Si-Cu-Mg alloy is about 0.27% and 0.1% respectively. Due to the formation of some coarse Cd-rich phases and pure Cd particles the mechanical properties of alloy decrease when Cd amount exceeds0.27%. When more than 0.1% Sn added, some Sn atoms form low-melting eutectic compound at grain boundary, and then cause over-burning in alloy when solution treated, which may deteriorate properties of alloy, especially ductility of alloy.On the other hand, the addition of Cd and Sn remarkably increases the peak hardness and reduces the time to reach aging peak in Al-Si-Cu-Mg alloy. The action of Cd/Sn in quaternary Al-Si-Cu-Mg alloy is effectively the same as that occur in binary Al-Cu alloy that the enhanced hardening associated with Cd / Sn addition is due to the promotion of the θ' phase.

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

    International Nuclear Information System (INIS)

    X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu2Cd1-zMnzSnSe4 and Cu2Cd1-zFezSnSe4 alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. For Cu2Cd0.8Fe0.2SnSe4 as well as for Cu2Cd0.2Fe0.8SnSe4 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 Cu2Cd1-zMnzSnSe4 and Cu2Cd1-zFezSnSe4 alloy systems, only two single solid phase fields, the tetragonal stannite α(I4-bar2m) and the wurtz-stannite δ (Pmn21) 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 FeSe2 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.

  6. Structural and optical properties of Cu-doped CdTe films with hexagonal phase grown by pulsed laser deposition

    OpenAIRE

    F. de Moure-Flores; J. G. Quiñones-Galván; A. Guillén-Cervantes; Santoyo-Salazar, J.; A. Hernández-Hernández; Olvera, M. de la L.; M. Zapata-Torres; Meléndez-Lira, M.

    2012-01-01

    Cu-doped CdTe thin films were prepared by pulsed laser deposition on Corning glass substrates using powders as target. Films were deposited at substrate temperatures ranging from 100 to 300 °C. The X-ray diffraction shows that both the Cu-doping and the increase in the substrate temperature promote the presence of the hexagonal CdTe phase. For a substrate temperature of 300 °C a CdTe:Cu film with hexagonal phase was obtained. Raman and EDS analysis indicate that the films grew with an excess ...

  7. The properties of CdTe solar cells with ZnTe/ZnTe: Cu buffer layers

    Institute of Scientific and Technical Information of China (English)

    Song Huijin; Zheng Jiagui; Feng Lianghuan; Yan Qiang; Lei Zhi; Wu Lili; Zhang Jingquan; Li Wei; Li Bing

    2008-01-01

    CdS/CdTe solar cells with ZnTe/ZnTe:Cu buffer layers were fabricated and studied. The energy band structure of it was analyzed. The C-V, I-V characteristics and the spectral response show that the ZnTe/ZnTe:Cu buffer layers improve the back contact characteristic properties, the diode characteristics of the forward junction and the short-wave spectral response of the CdTe solar cells. The ZnTe/ZnTe:Cu buffer layers affect the solar cell conversion efficiency and its fill factor.

  8. Hot Deformation Characteristics and Processing Maps of the Cu-Cr-Zr-Ag Alloy

    Science.gov (United States)

    Zhang, Yi; Chai, Zhe; Volinsky, Alex A.; Sun, Huili; Tian, Baohong; Liu, Ping; Liu, Yong

    2016-03-01

    The hot deformation behavior of the Cu-Cr-Zr-Ag alloy has been investigated by hot compressive tests in the 650-950 °C temperature and 0.001-10 s-1 strain rate ranges using Gleeble-1500D thermo-mechanical simulator. The microstructure evolution of the alloy during deformation was characterized using optical and transmission electron microscopy. The flow stress decreases with the deformation temperature and increases with the strain rate. The apparent activation energy for hot deformation of the alloy was 343.23 kJ/mol. The constitutive equation of the alloy based on the hyperbolic-sine equation was established to characterize the flow stress as a function of the strain rate and the deformation temperature. The processing maps were established based on the dynamic material model. The optimal processing parameters for hot deformation of the Cu-Cr-Zr-Ag alloy are 900-950 °C and 0.001-0.1 s-1 strain rate. The evolution of DRX microstructure strongly depends on the deformation temperature and the strain rate.

  9. Synthesis of Magnetite in Presence of Cu2+ or Cr3+

    International Nuclear Information System (INIS)

    The effects of Cu or Cr ions on the formation of magnetite, which were prepared by two different methods, were studied by 57Fe Moessbauer spectrometry. The first synthesis procedure consisted in an alkaline hydrolysis of ferrous chloride solution in accordance with literature reports. The second method, which was a variation of a reported synthetic route, consisted of a reaction of a 2:1 Fe(II)/Fe(III) solution under alkaline conditions in the presence of an oxidant agent. The samples were also prepared in the presence of chromium or copper chloride solutions. Our results showed that the magnetites obtained via the first procedure exhibits a higher degree of stoichiometry and a better crystalline quality than those prepared by the second route. It seems that the presence of chromium helped the formation of goethite, whereas the presence of copper interfered with it in agreement with other works. We observed that the magnetites obtained in the presence of copper were of poorer crystallinity than the ones obtained with chromium. Finally, the influence of Cu or Cr upon the magnetic and crystalline properties of the two series of magnetites is also presented and discussed

  10. 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

  11. 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)

    Photovoltaic cells with the structure Glass/Mo/Cu(In,Ga)S2/CdS/i-ZnO/n+-ZnO are currently among the most successful and promising thin-layer solar cells. In this system, the Cu(In,Ga)S2 (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)S2/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)S2/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)S2 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 readily

  12. 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

    Thermal treatment of chromated copper arsenate (CCA) impregnated waste wood is a way to utilize the energy resource of the wood and at the same time to reduce the volume of the waste. An issue of concern in relation to the thermal treatment is As emission to the air. Meanwhile, there is still...... 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...... from pyrolysis of treated waste wood. By SEM/EDX it was seen that the charcoal still showed wood structure with both tracheids and rays and that Cu, Cr and As were found inside this wood structure. Cu was found alone while Cr and As were often found together. By chemical analysis it was found, too...

  13. Low voltage tunneling magnetoresistance in CuCrO{sub 2}-based semiconductor heterojunctions at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Li, X. R.; Han, M. J.; Shan, C.; Hu, Z. G., E-mail: zghu@ee.ecnu.edu.cn; Zhu, Z. Q.; Chu, J. H. [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Wu, J. D. [Department of Optical Science and Engineering, Fudan University, Shanghai 200433 (China)

    2014-12-14

    CuCrO{sub 2}-based heterojunction diodes with rectifying characteristics have been fabricated by combining p-type Mg-doped CuCrO{sub 2} and n-type Al-doped ZnO. It was found that the current for the heterojunction in low bias voltage region is dominated by the trap-assisted tunneling mechanism. Positive magnetoresistance (MR) effect for the heterojunction can be observed at room temperature due to the tunneling-induced antiparallel spin polarization near the heterostructure interface. The MR effect becomes enhanced with the magnetic field, and shows the maximum at a bias voltage around 0.5 V. The phenomena indicate that the CuCrO{sub 2}-based heterojunction is a promising candidate for low-power semiconductor spintronic devices.

  14. Effect of vacuum heat treatment on microstructure and microhardness of cold sprayed Cu-4Cr-2Nb alloy coating

    Institute of Scientific and Technical Information of China (English)

    LI Wen-ya; GUO Xue-ping; L. DEMBINSKI; LIAO Han-lin; C.CODDET

    2006-01-01

    The effect of vacuum heat treatment on the microstructure and microhardness of cold-sprayed Cu-4%Cr-2%Nb alloy coating was investigated. The heat treatment was conducted under the temperatures from 250 ℃ to 950 ℃ with a step of 100 ℃ for 2 h. It was found that a dense thick Cu-4Cr-2Nb coating could be formed by cold spraying. After heat treatment,a Cr2Nb phase was uniformly distributed in the matrix,which was transferred from the gas-atomized feedstock. A little grain growth of Cr2Nb phase was observed accompanying with the healing-up of the incomplete interfaces between the deposited particles at the elevated temperatures. The coating microhardness increases a little with increasing the temperature to 350 ℃,and then decreases with further increasing temperature up to 950 ℃. This fact can be attributed to the microstructure evolution during the heat treatment.

  15. Low-field magnetic properties of amorphous and nanocystalline FeCrCuNbSiB alloys

    International Nuclear Information System (INIS)

    The AC susceptibility dependence on magnetic field, time and temperature of amorphous as well as nanocrystalline Fe73.5-xCrxCu1Nb3Si13.5B9 (x=0-4) alloys was studied. Micromagnetic model is used for calculating the activation energy spectra (AES) of the magnetic after-effect (MAE). It was observed that addition of Cr to the amorphous FeCrCuNbSiB alloys highly decreases the amplitude of the MAE so that no MAE is observed for Cr content higher than 2 at%. After annealing at 550 deg. C, the initial susceptibility increases as a result of magnetic softening during nanocrystallization and the MAE vanishes. The nanocrystalline state was characterized by the high magnetic as well as structural stability. Moreover, addition of 1 at% Cr makes the initial susceptibility of the nanocrytalline sample higher than in the FINEMET alloy

  16. 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

  17. 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. PMID:25065788

  18. Effect of sintering on the relative density of Cr-coated diamond/Cu composites prepared by spark plasma sintering

    Science.gov (United States)

    Cui, Wei; Xu, Hui; Chen, Jian-hao; Ren, Shu-bin; He, Xin-bo; Qu, Xuan-hui

    2016-06-01

    Cr-coated diamond/Cu composites were prepared by spark plasma sintering. The effects of sintering pressure, sintering temperature, sintering duration, and Cu powder particle size on the relative density and thermal conductivity of the composites were investigated in this paper. The influence of these parameters on the properties and microstructures of the composites was also discussed. The results show that the relative density of Cr-coated diamond/Cu reaches ~100% when the composite is gradually compressed to 30 MPa during the heating process. The densification temperature increases from 880 to 915°C when the diamond content is increased from 45vol% to 60vol%. The densification temperature does not increase further when the content reaches 65vol%. Cu powder particles in larger size are beneficial for increasing the relative density of the composite.

  19. Magnetni nanodelci na osnovi zlitin NiCu in NiCr za uporabo v samoregulativni magnetni hipertermiji

    OpenAIRE

    Stergar, Janja

    2014-01-01

    V doktorskem delu smo obravnavali sintezo in karakterizacijo nanodelcev zlitin NiCu in NiCr za uporabo v samoregulativni magnetni hipertermiji. V prvem delu smo pripravili zlitine NiCu in NiCr s tremi različnimi sinteznimi postopki: mehansko mletje, sinteza s pomočjo mikroemulzij in sol-gel metoda, pri čemer smo preučevali reakcijske pogoje posamezne sinteze. Sledila je karakterizacija pridobljenih zlitin s pomočjo rentgenske praškovne difrakcije, transmisijske elektronske mikroskopije, ma...

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

    International Nuclear Information System (INIS)

    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)

  1. Effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy

    Indian Academy of Sciences (India)

    G Durashevich; V Cvetkovski; V Jovanovich

    2002-02-01

    The CuCrZr alloy undergoes processes of precipitation during ageing. Besides precipitation hardening the strength is affected by cold deformation which is performed before and after ageing. The cold deformation (1) before ageing accelerates the process of strength hardening, since it induces higher rate of precipitation from the saturated -solid solution. Cold deformation (2) after ageing primarily affects the alloy strength. In this paper the results of the effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy are presented. The aim of the paper was to evaluate the most suitable combination of thermomechanical treatment and alloy properties.

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

    International Nuclear Information System (INIS)

    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/m3 , 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

  3. Electrodialytic extraction of Cd and Cu from sediment from Sisimiut Harbour, Greenland

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Nystrøm, Gunvor Marie; Jensen, Pernille Erland; Villumsen, Arne

    2007-01-01

    an applied current density of 1.2 mA/cm2. However, it was seen that the removal rate decreased considerably after 3 days with an applied current density of 0.5 mA/cm2 and the major part of the two heavy metals was removed during the first 3 days (the Cu concentration was reduced with 74% and the Cd...... evaluate the removal rate of the two heavy metals. The sediment was suspended in distilled water during application of current. Both heavy metals were removed successfully. The Cu concentration was reduced from 97 to 16 mg/kg and the Cd concentration was reduced from 0.55 to 0.03 mg/kg after 28 days with...

  4. Adsorption of Cu2+, Zn2+ and Cd2+ on Bacillus subtilis

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A process of biosorption of Cu2+, Zn2+ and Cd2+ on Bacillus subtilis was investigated.The experiments show that the process of biosorption is quite fast. The maximum adsorption was reached after 5 min and hardly changed with time. The experimental data was analyzed using four sorption kinetic models: the pseudo-first-order, the Ritchie second-order, the modified second-order and the Elovich equations, which helped to determine the best-fit equation for the sorption of metal ions onto biomass. The results show that both the Ritchie second-order and modified secondorder equations can fit the experimental data. The Langmuir model is able to accurately describe adsorption of Cu2+ and Zn2+ on B. subtilis. The experimental data points of adsorption Cd2+ and Zn2+ on B. subtilis are described by Freundlich isotherms model.

  5. 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

  6. On the valence state of Hg in (Hg, Cr)Sr2CuO4+δ superconductor

    International Nuclear Information System (INIS)

    The 1201-type of superconducting samples of nominal composition (Hg0.7Cr0.3)Sr2CuO4+δ, were synthesised in partial vacuum and subsequently annealed in oxygen and argon. The Tc onset for the different samples is found to be ∼58 K. Hg LIII-edge measurements have clearly shows that Hg is in divalent state in all the (Hg,Cr)-1201 samples. (author)

  7. Accumulation of Pb, Cd, Cu and Zn in plants and hyperaccumulator choice in Lanping lead-zinc mine area, China.

    Science.gov (United States)

    Yanqun, Zu; Yuan, Li; Schvartz, Christian; Langlade, Laurent; Fan, Liu

    2004-06-01

    A field survey of higher terrestrial plants growing on Lanping lead-zinc mine, China were conducted to identify species accumulating exceptionally large concentrations of Pb, Cd, Cu and Zn of 20 samples of 17 plant species. Concentrations of Pb and Zn in soil and in plant were higher than that of Cu and Cd. Significant difference was observed among the average concentrations of four heavy metals in plants (except Cd and Cu) and in soil (except Pb and Zn) (Ptree>herbaceous, and herbaceous grew in soil with the highest concentrations of four heavy metals. In different areas, the concentrations of Pb, Cd, Cu and Zn in plants and soils and enrichment coefficient were different. Plants in Paomaping had more accumulating ability to Pb, Cd and Zn, and plants in Jinfeng River had more accumulating ability to Cu. Six plant species, i.e. S. cathayana, Lithocarpus dealbatus, L. plyneura, Fargesia dura, Arundinella yunnanensis and R. annae in Paomaping, had high accumulation capacity. R. annae in Paomaping had hyperaccumulating capacity to Pb, Cd and Zn, L. plyneura to Pb and Cd, and S. cathayana to Cd, respectively. PMID:15031017

  8. Biosorption of Cr (Ⅵ), Cr (Ⅲ), Pb (Ⅱ) and Cd (Ⅱ) from Aqueous Solutions by Sargassum wightii and Caulerpa racemosa Algal Biomass

    Institute of Scientific and Technical Information of China (English)

    Narayanaswamy Tamilselvan; Kumar Saurav; Krishnan Kannabiran

    2012-01-01

    Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative technology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemical pathways of uptake.Even though several physical and chemical methods are available for removal of heavy metals,currently many biological materials such as bacteria,algae,yeasts and fungi have been widely used due to their good performance,low cost and large quantity of availability.The aim of the present study is to explore the biosorption of toxic heavy metals,Cr(Ⅵ),Cr(Ⅲ),Pb(Ⅱ) and Cd(Ⅱ) by algal biomass obtained from algae Sargassum wightii (brown) and Caulerpa racemosa (green).Biosorption of algal biomass was found to be biomass concentration- and pH-dependent,while the maximal biosorption was found at pH 5.0 and with the metal concentration of 100 mgL-1.S.wightii showed the maximal metal biosorption at the biomass concentration of 25 g L-1,followed by C.racemosa with the maximal biosorption at 30gL1.S.wightii showed 78% biosorption of Cr(Ⅵ),Cr(Ⅲ),Pb(Ⅱ) and Cd(Ⅱ) ions.C.racemosa exhibited 85% biosorption of Cd(Ⅱ) and Cr(Ⅵ),and 50% biosorption of Cr(Ⅲ) and Pb(Ⅱ).The results of our study suggest that seaweed biomass can be used efficiently for biosorption of heavy metals.

  9. Biosorption mechanisms of Cd2+, Cu'2+, and Pb2+ using micro granules of sargassum cristaefolium

    International Nuclear Information System (INIS)

    The physico-chemical removal of toxic heavy metals from wastewater systems by inexpensive alternatives is a desired environmental clean-up strategy. Biosorption is one alternative that requires biomass with high metal uptake, selectivity and an ability to cope with mechanical stress in bioremediation conditions. The biosorption mechanisms of Cd2+, Cu2+ and Pb2+ by micro granules of brown algae (Sargassum cristaefolium) were investigated on a series of batch experiments coupled with Flame Atomic Absorption (FAAS) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, Energy Dispersive X-ray (EDX), and Scanning Electron Microscopy analyses. It was observed that soluble ions of Cd2+, Cu2+ and Pb2+ could be removed by micro granules of brown algae through possible mechanisms of ion exchange, chelation, chemical precipitation, and binding to extracellular polymer. Lead exhibits the highest affinity to the algal biomass followed by copper and cadmium, SEM analysis showed uptake of Cd2+, Cu2+ and PB2+ by Sargassum cristaefolium could bring about significant morphological changes such as distortion and disorientation of the surface layers. This phenomenon signifies depositions of metals in the cell wall matrix of the brown algae. Significant changes in the FTIR and EDX spectrum were observed after Cd2+, Cu2+ and Pb2+ sorption, which stipulated the participation of surface functional groups associated with hydroxyl groups of alcohol in sorption interactions; and during the ion exchange process, ions (Ca2+,Mg2+, H+,Na+, and K+) originally present in the algal biomass were displaced by the heavy metals under study. (author)

  10. Mobility and speciation of Cd,Cu,and Zn in two acidic soils affected by simulated acid rain

    Institute of Scientific and Technical Information of China (English)

    GUO Zhao-hui; LIAO Bo-han; HUANG Chang-yong

    2005-01-01

    Through a batch experiment, the mobility and speciation of heavy metals(Cd, Cu, Zn) in two acidic forest soils from Hunan Province were studied. The results showed that the release and potential active speciation of Cd, Cu, and Zn in the tested contaminated red soil(CRS) and yellow red soil(CYRS) increased significantly with pH decreasing and ion concentrations increasing of simulated acid rain, and these effects were mainly decided by the pH value of simulated acid rain. Cd had the highest potential risk on the environment compared with Cu and Zn. Cd existed mainly in exchangeable form in residual CRS and CYRS, Cu in organically bound and Mn-oxide occluded forms, and Zn in mineral forms due to the high background values.

  11. Dissolved Cu, Pb, Zn and Cd in the South China Sea surface waters

    Institute of Scientific and Technical Information of China (English)

    Huo Wenmian; Ji Weidong; Xu Kuncan

    2001-01-01

    A total of 106 surface water samples were collected in the South China Sea during two transects in June and December 1998. The samples were collected with strictly contamination free procedure and trace metals were measured by clean laboratory methods and GFAAS. The mean concentrations for the dissolved fractions are: Cu 0.100 μg/dm3, Pb 0.060 μg/dm3, Zn 0.086 μg/dm3, Cd 0.007 μg/dm3, which is close to the world open ocean's level. The spatial distribution of the trace heavy metals shows higher concentrations in offshore area and lower concentrations in the central in the South China Sea, and the concentrations decrease with the distance from the offshore, which suggests the existence of significant continental shelf input of the trace heavy metals. The correlationship among the elements is better in summer than that in winter. Cu is positively correlated with Cd in both seasons and it is also found for the first time that they are positively correlated with nutrients in the South China Sea surface waters which further indicate the biogeochemical cycle of these elements in the marine environment. The baseline value of Cu, Pb, Zn, Cd in the South China Sea surface waters is obtained through statistical analysis.

  12. Metal stoichiometry in predicting Cd and Cu toxicity to a freshwater green alga Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    In this study, we quantified the accumulation and toxicity of cadmium and copper in a freshwater green alga, Chlamydomonas reinhardtii, under different phosphate conditions. The accumulated Cd and Cu concentrations increased significantly with increasing ambient P concentrations and free metal ion concentrations. The metal:P ratio remained independent of the ambient P concentration. For the three pulse-amplitude-modulated parameters, the median inhibition concentrations were 1.5-1.6x and 2.0x higher, but the medium inhibition cellular quota was 2.2x and 1.2x lower for cells maintained at 0.1 μM P than for cells maintained at 10 μM P for Cd and Cu, respectively. Furthermore, the difference in metal toxicity decreased (for Cd) or disappeared (for Cu) when the toxicity was expressed by the metal:P ratio in the cells, indicating that the stoichiometry of metals and P can be better used to predict the toxicity of metals. It is necessary to consider the stoichiometry of metals in predicting metal toxicity in phytoplankton. - The stoichiometry of metals and P can be used to predict metal toxicity to freshwater phytoplankton under different P conditions

  13. 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.

  14. Estudio estructural de polvos Cu-Cr aleados mecánicamente

    Directory of Open Access Journals (Sweden)

    Aguilar, C.

    2006-10-01

    Full Text Available The changes of grain size, microstrain, stacking fault probability, stacking fault energy and dislocations density on powder mixtures of copper with 1 and 3 weight % after high energy mechanical milling. The X-ray diffraction profile was analysed by Williamson-Hall (W-H method. Grain size decreased with the increase of milling time, until values of 106 and 59 nm for 1 and 3 weight % Cr, respectively. As well microstrain increased with milling time. Stacking fault probability increased in function of milling time to value between 1x10–3–8x10–3 for Cu–1 weight % Cr and 3x10–3–8x10–3 for Cu–3 weight % Cr. The stacking fault energy decreased with milling time and amount of chromium. Finally, the dislocations density is between a range between 1x1014–1x1015 m/m3.

    El presente trabajo estudia cambios de tamaño de grano, microdeformación, probabilidad de falla de apilamiento, energía de falla de apilamiento y densidad de dislocaciones en mezclas de polvos de cobre con adición de 1 y 3% peso de cromo, sometidas a molienda mecánica de alta energía. Los perfiles de difracción de rayos X, obtenidos de las muestras, se analizaron con la metodología de Williamson-Hall (W-H. El tamaño de grano disminuyó con el incremento del tiempo de molienda, hasta valores de 106 y 59 nm para 1 y 3% peso Cr, respectivamente. A su vez los valores de microdeformación aumentaron con el tiempo de molienda. La probabilidad de falla de apilamiento, de igual forma, aumentó en función del tiempo de molienda. Se obtuvieron valores entre 1x10–3-8x10–3 para Cu-1% peso Cr y 3x10–3–8x10-3 para Cu–3% peso Cr. La energía de falla de apilamiento disminuyó en función del tiempo de molienda y porcentaje de cromo. Finalmente, los valores de densidad de dislocaciones se encuentran en un rango de 1x1014–1x1015 m/m3

  15. Antioxidative role of selenium on some tissues of (Cd2+), Cr3+)-induced rainbow trout.

    Science.gov (United States)

    Orun, Ibrahim; Talas, Zeliha Selamoglu; Ozdemir, Ilknur; Alkan, Aysel; Erdogan, Kenan

    2008-09-01

    Chemical toxic pollutants (especially heavy metals) are important sources of reactive oxygen species (ROS) in biological systems. Membrane phospholipids of aerobic organisms are continually subjected to oxidant challenges from endogenous and exogenous sources, while peroxidized membranes and lipid peroxidation products represent constant threats to aerobic cells. The primary antioxidant protection against free radical and ROS is provided by the enzymes glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT), respectively. The trace element selenium has been implicated in chemo-prevention and drug-resistance through reduction of oxidative stress. Selenium could prevent damage to the unsaturated fatty acid of subcellular membranes by lipid peroxidation induced by free radicals. The results reported here show that sodium selenite has an important contribution to antioxidative defense for the spleen and heart of rainbow trout. The ability of sodium selenite to prevent the oxidative stress induced by heavy metals (Cd(2+), Cr(3+)) in fish was rationalized. PMID:17920681

  16. Levels Of Heavy Metals (Hg, Pb, Cd, And Cr In Tissues Of Trachurus Trachurus

    Directory of Open Access Journals (Sweden)

    Enkeleda Ozuni

    2012-09-01

    Full Text Available The study was carried out to monitor the concentration level of mercury, lead, cadmium and chrome in different tissues of Trachurus trachurus (Horse mackerel. The concentration level of heavy metals was measured by using atomic absorption spectrophotometer (AAS. Concentrations of heavy metals in muscle tissue and liver of this animal ranged as follows: Hg 0.032-0.106; Cd nd-0.067 mg/kg wet weight; Pb and Cr resulted always below the detection level (nd in all tissue samples. According to the results the concentration levels of heavy metals measured in the muscle tissue was lower than the maximum permitted level for human consumption set by EC and Albanian regulation. The results obtained from the study indicate that heavy metal levels are in acceptable limits, so this product can be used as food for human consumption.

  17. Cd, Ni, Cr and Pb distribution in biosolid pellets used as soil amendment

    Science.gov (United States)

    Jordán, Manuel M.; Rincón-Mora, Beatriz; Belén Almendro-Candel, María; Navarro Pedreño, Jose; Gómez Lucas, Ignacio; Bech, Jaume; Roca, Nuria; Pardo, Francisco

    2016-04-01

    The application of biosolids to a soil is a method that offers important benefits (Navarro et al. 2003). The transport and application costs are quite low (mostly if they are dehydrated biosolids or pellets) if soils are located near a wastewater treatment plant. It is possible to recycle nutrients (N, P, and K) and organic matter by improving the physical and chemical characteristics of the soil and by reducing the fertilizer costs. However, the use of biosolids may also has several problems, such as the presence of quantities of metals that could be toxic for plants or could contaminate ground-waters after being leached. Heavy metals are one of the most serious environmental pollutants because of its high toxicity, abundance and easy accumulation by plant (Soriano-Disla et al. 2014; Rosen and Chen 2014). Contamination of soils by potentially toxic elements (e.g. Cd, Ni, Cr, Pb) from amendments of biosolids is subject to rigorous controls within the European Union. The present study was designed to examine the partition of selected heavy metals in biosolid pellets, and also to relate the distribution patterns of these metals. Samples were collected from the treatment of urban wastewater at the drying grounds of a wastewater processing plant. The samples correspond to biosolids with humidities below 20% and are representative of the three horizons within the pile: the isolation surface (H1), the mesophilous area (H2), and the thermophilous area (H3). Biosolid aggregates were placed in a pellet press and then compacted. Total content of metals was determined following microwave digestion and analysed by ICP/MS. Triplicate samples were weighed in polycarbonate centrifuge tubes and sequentially extracted. The distribution of chemical forms of Cd, Ni, Cr, and Pb in the biosolids was studied using a sequential extraction procedure that fractionates the metal into soluble-exchangeable, specifically sorbed-carbonate bound, oxidizable, reducible, and residual forms. The

  18. Study of the operation of Cu/sub 2/S-CdS solar cells of SAT type

    Energy Technology Data Exchange (ETDEWEB)

    Luquet, H.; Moussalli, G.-M.; Bougnot, J.; Perotin, M.; Savelli, M.

    1979-01-01

    Experimental results show that laws governing light and dark tunneling currents in Cu/sub 2/S-CdS solar cells of SAT (Societe Anonyme des Telecommunications) type correspond to tunnel conduction mechanisms. Assuming the existence of an interface layer limited by interface states between Cu/sub 2/S and CdS, results concerning capacitance measurements as a function of applied voltage are explained.

  19. Nerita chameleon as Biomonitoring Agent for Pb, Cd, Cu and Zn in Malaysian Intertidal Rocky Shore Environment

    OpenAIRE

    Mohd Fuad Miskon; Noor Azhar Mohd Shazili; Faridah Mohamad; Kamaruzzaman Yunus

    2015-01-01

    Pb, Cd, Cu and Zn in the soft tissue of Nerita chameleon from particular rocky shore sites along the east coast of Peninsular Malaysia were investigated. Samples were measured using ICP-MS with standard configuration. The metal accumulation patterns indicate consistent enrichment of essential metals. Locations with relatively high concentrations of the contaminant metals Pb, Cd and Cu are related to their close proximity to industrial activities and urban sites. Comparison with maximum permis...

  20. CdS quantum dots modified CuO inverse opal electrodes for ultrasensitive electrochemical and photoelectrochemical biosensor

    OpenAIRE

    Xia, Lei; Xu, Lin; Song, Jian; Xu, Ru; Liu, Dali; Dong, Biao; SONG, HONGWEI

    2015-01-01

    The CuO inverse opal photonic crystals (IOPCs) were synthesized by the sol-gel method and modified with CdS quantum dots by successive ionic layer adsorption and reaction (SILAR). CdS QDs modified CuO IOPCs FTO electrodes of different SILAR cycles were fabricated and their electrochemical properties were studied by cyclic voltammetry (CV) and chronoamperometry (I–t). Structure and morphology of the samples were characterized by transmission electron microscopy (TEM), scanning electron microsc...

  1. 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.

  2. 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)

    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

  3. Effect of ultrasonic vibration on the dechromisation corrosion of a CuCr alloy in HCl solution

    Institute of Scientific and Technical Information of China (English)

    XU Tao; GAO Huawei; LIU Jianhua; YU Cuiyan

    2007-01-01

    The effect of ultrasonic vibration on the dechromisation corrosion of a CuCr alloy in HCl solution was studied and the corrosion mechanisms were analyzed. It is found that ultrasonic vibration reduces the dechromisation incubation time, accelerates the dechromisation corrosion rate, decreases the temperature and concentration of HCl solution, and when the dechromisation occurs it seriously weakens the microstructure of dechromisation layer. It is concluded that ultrasonic vibration can accelerate destruction of the passivation film on the Cr surface and increase the activities of Cl- and Cr.

  4. Effects of CdCl2 on the maternal-to-fetal clearance of 67Cu and placental blood flow

    International Nuclear Information System (INIS)

    Copper is an essential element while Cd is an extremely toxic heavy metal of questionable biological usefulness. Cadmium has been reported to interfere with the metabolism of Cu, be teratogenic, and decrease blood flow in the fetal placenta. Because of these reported biological interactions of Cd and Cu, this investigation was conducted to determine the effects of Cd on placental transport of 67Cu and placental blood flow in the guinea pig. All guinea pigs used were 60 +/- 1 days pregnant. A placental perfusion technique was used to measure the maternal-to-fetal clearance of 67Cu and 3H2O across the placenta. The clearance of 3H2O served as an indicator of placental blood flow on the maternal side of the circulation. The results indicated that an iv injection of 1 mg Cd/kg body weight resulted in an immediate increase in the clearance of 67Cu which declined over the next 8 min to an elevated level compared to the extrapolated best-fit curve of control values. This iv injection of CdCl2 concomitantly reduced the maternal-to-fetal clearance of 3H2O across the placenta. In conclusion, an acute exposure of the pregnant female to CdCl2 results in an increased maternal-to-fetal clearance 67Cu and a reduced placental blood flow that can alter the supply of nutrients to the developing embryo or fetus, and therefore modify normal development

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

    International Nuclear Information System (INIS)

    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. (paper)

  6. 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

    2013-07-01

    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. PMID:23732175

  7. 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.

  8. The use of copper alloy CuCrZr as a structural material for actively cooled plasma facing and in vessel components

    Energy Technology Data Exchange (ETDEWEB)

    Lipa, M.; Durocher, A. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Tivey, R. [ITER, Garching Joint Work Site, Garching (Germany); Huber, Th.; Schedler, B. [Plansee AG, Reutte (Austria); Weigert, J. [PTR Praezisionstechnik GmbH, Maintal-Doernigheim (Germany)

    2004-07-01

    This paper presents our experience with precipitation hardened CuCrZr in the fabrication of actively cooled components for Tore Supra (toroidal pump limiter fingers, guard limiter heat sink hollow-profiles, ripple protection tubes, endoscope heads) and JET high heat flux elements for the beam-lines. The supposed interplay phenomenon between CuCrZr procurement, component geometry and welding procedure is discussed. The associated mechanical characterisation of materials from different suppliers and component joining, focused especially on CuCrZr-CuCrZr fusion weldings using electron beams, is presented. The behaviour of an actively cooled CuCrZr component during accidental operation conditions in Tore Supra is described. (authors)

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

    DEFF Research Database (Denmark)

    Singh, B.N; Edwards, D.J.; Tähtinen, S.

    2004-01-01

    A number of specimens of CuCrZr alloy was prime aged and then overaged at 600oC for 1, 2 and 4 hours and for 4 hours at 700 and 850oC. After different heat treatments, both the precipitate microstructure and mechanical properties were characterized.Mechanical properties were determined at 50 and...... 300oC. Some selected specimens in the prime aged as well as overaged conditions were irradiated in the BR-2 reactor at Mol at 60 and 300oC to a displacement dose level of ~0.3 dpa. Irradiated specimens weremechanically tested at 60 and 300oC. The post-deformation microstructure of the irradiated...

  10. Biosorption of binary mixtures of Cr(III and Cu(II ions by Sargassum sp

    Directory of Open Access Journals (Sweden)

    Silva E.A.

    2003-01-01

    Full Text Available The adsorption of two metal ions, Cr(III and Cu(II, in single-component and binary systems by Sargassum sp., a brown alga, was studied. Equilibrium batch sorption studies were carried out at 30ºC and pH 3.5. Kinetic tests were done for a binary mixture (chromium + copper for a contact time of 72 hours to guarantee that equilibrium was reached. The monocomponent equilibrium data obtained were analyzed using the Langmuir and Freundlich isotherms. The binary equilibrium data obtained were described using four Langmuir-type and Freundlich isotherms. The F-test showed a statistically significant fit for all binary isotherm models. The parameters for isotherms of the Langmuir-type were used to determine the affinity of one metal for the biosorbent in the presence of another metal. The chromium ion showed a greater affinity for Sargassum sp. than the copper ion.

  11. Properties and features of structure formation CuCr-contact alloys in electron beam cladding

    Energy Technology Data Exchange (ETDEWEB)

    Durakov, Vasiliy G., E-mail: electron@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Dampilon, Bair V., E-mail: dampilon@ispms.tsc.ru, E-mail: gnusov@rambler.ru; Gnyusov, Sergey F., E-mail: dampilon@ispms.tsc.ru, E-mail: gnusov@rambler.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055, Russia and National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2014-11-14

    The microstructure and properties of the contact CuCr alloy produced by electron-beam cladding have been investigated. The effect of the electron beam cladding parameters and preheating temperature of the base metal on the structure and the properties of the coatings has been determined. The bimodal structure of the cladding coating has been established. The short circuit currents tests have been carried out according to the Weil-Dobke synthetic circuit simulating procedure developed for vacuum circuit breakers (VCB) test in real electric circuits. Test results have shown that the electron beam cladding (EBC) contact material has better breaking capacity than that of commercially fabricated sintered contact material. The application of the technology of electron beam cladding for production of contact material would significantly improve specific characteristics and reliability of vacuum switching equipment.

  12. Energy levels and radiative rates for Cr-like Cu VI and Zn VII

    CERN Document Server

    Aggarwal, K M; Keenan, F P; Kisielius, R

    2016-01-01

    Energy levels and radiative rates (A-values) for transitions in Cr-like Cu~VI and Zn~VII are reported. These data are determined in the quasi-relativistic approach (QR), by employing a very large {\\em configuration interaction} (CI) expansion which is highly important for these ions. No radiative rates are available in the literature to compare with our results, but our calculated energies are in close agreement with those compiled by NIST and other available theoretical data, for a majority of the levels. The A-values (and resultant lifetimes) are listed for all significantly contributing E1, E2 and M1 radiative transitions among the energetically lowest 322 levels of each ion.

  13. Gas sensing properties of Cu and Cr activated BST thick films

    Indian Academy of Sciences (India)

    G H Jain; L A Patil

    2006-08-01

    H2S gas sensing properties of BST ((Ba0.67Sr0.33)TiO3) thick films are reported here for the first time. BST ceramic powder was prepared by mechanochemical process. Thick films of BST were prepared by screen-printing technique. The sensing performance of the films was tested for various gases. The films were surface customized by dipping them into aqueous solutions of CuCl2 and CrO3 for various intervals of time. These surface modified BST films showed improved sensitivity to H2S gas (100 ppm) than pure BST film. Chromium oxide was observed to be a better activator than copper oxide in H2S gas sensing. The effect of microstructure and amount of activators on H2S gas sensing were discussed. The sensitivity, selectivity, stability, response and recovery time of the sensor were measured and presented.

  14. Aging effect in (Hg,Cr)Sr2CuO4+δ superconductor

    International Nuclear Information System (INIS)

    The aging effect on the structural stability and superconducting properties of (Hg0.7Cr0.3)Sr2CuO4+δ was investigated, from the date of its preparation, and after every four months interval, by XRD, FT-IR and ac-susceptibility measurements. A slow degradation in diamagnetic signal was noted up to 8 months and the sample was non-superconducting at the end of 12 months. Although, XRD patterns were not altered much, but a considerable change in the a lattice parameter was noted for the aged samples suggesting a possible deterioration in the sample quality. This observation was well supported by FT-IR studies where a broad absorption band at ∼ 700 and ∼ 1450 cm-1 was clearly noticed in the case of non-superconducting samples owing to the formation of carbonate species. (author)

  15. Temperature dependent lattice instability in single crystals of ferromagnetic CdCr2Se4 diluted with In and Sb

    DEFF Research Database (Denmark)

    Waskowska, A.; Gerward, Leif; Olsen, J.S.; Morgenroth, W.; Malicka, E.; Skrzypek, D.

    2008-01-01

    to occur at the same temperature as the magnetic transition, T-c = 130 K, which also is the same T-c as for the parent crystal CdCr2Se4. The low temperature phase has been described in orthorhombic space group Fddd. For In admixture, a structural transition occurs in the paramagnetic state at about T...

  16. Synthesis and Photoluminescent Properties of ZnSe: Cu/CdS Core/Shell Quantum Dots%ZnSe:Cu/CdS核壳量子点的合成及光学性能研究

    Institute of Scientific and Technical Information of China (English)

    王磊; 曹立新; 柳伟; 苏革

    2013-01-01

    Water-soluble ZnSe∶ Cu quantum dots were synthesised in aqueous solution,ZnSe∶ Cu/CdS core/shell quantum dots(QDs) with different shell thickness were obtained in this paper.The influence of shell thickness on the optical properties of ZnSe∶ Cu QDs was studied.The samples were characterized by TEM,XRD,PL and UV-Vis.The results showed that ZnSe∶ Cu/CdS core/shell QDs have a cubic zinc-blende structure and are spherical with good dispersibility.The average grain size increased from 2.7 to 4.0 nm after the shell modification.The redshift of core/shell QDs compared with the core QDs was observed in both the UV-Vis and the PL spectra,which suggested that the size of core/shell QDs increased.The results proved that CdS shell were coated on the surface of ZnSe∶ Cu QDs and formed the ZnSe∶ Cu/CdS core/shell structure QDs.The PL intensity of the ZnSe∶ Cu QDs decreased with higher stability after being coated by CdS shell.%以CdS为壳层材料对核水溶性ZnSe:Cu量子点进行包覆,得到ZnSe:Cu/CdS核壳结构的量子点.研究了壳层厚度对ZnSe:Cu量子点光学性能的影响,采用TEM、XRD、PL和UV-Vis手段对所得样品进行表征.实验结果表明:量子点为立方闪锌矿结构,分散性好,形状为球形,经壳层修饰后量子点的粒径由2.7 nm增大到4.0 nm.随着包覆CdS壳层数的增加,量子点的发射和紫外吸收谱红移,说明量子点在长大,证明CdS壳层生长在ZnSe:Cu量子点的表面,形成了核壳结构的ZnSe:Cu/CdS量子点.包覆CdS壳层后ZnSe:Cu量子点的发光强度减弱,但稳定性得到了提高.

  17. 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 m

  18. Modeling of electrodialytic and dialytic removal of Cr, Cu and As from CCA-treated wood chips

    DEFF Research Database (Denmark)

    Ribeiro, Alexandra; Rodriguez-Maroto, J.M.; Mateus, Eduardo;

    2007-01-01

    A one-dimensional model is developed for simulating the electrodialytic and dialytic treatment of a saturated bed of wood chips containing chromium, copper and arsenic. The movement of Cr, Cu and As is mathematically modeled taking into account the diffusion transport resulting from the concentra...

  19. Characterization of Cold Sprayed CuCrAl-Coated and Uncoated GRCop-84 Substrates for Space Launch Vehicles

    Science.gov (United States)

    Raj, S. V.; Karthikeyan, J.; Lerch, B. A.; Barrett, C.; Garlich, R.

    2007-01-01

    A newly developed Cu-23(wt.%)Cr-5%Al (CuCrAl) alloy is currently being considered as a protective coating for GRCop-84 (Cu-8(at.%)Cr-4%Nb). The coating was deposited on GRCop-84 substrates by the cold spray deposition technique. Cyclic oxidation tests conducted in air on both coated and uncoated substrates between 773 and 1073 K revealed that the coating remained intact and protected the substrate up to 1073 K. No significant weight loss of the coated specimens were observed at 773 and 873 K even after a cumulative cyclic time of 500 h. In contrast, the uncoated substrate lost as much as 80% of its original weight under similar test conditions. Low cycle fatigue tests revealed that the fatigue lives of thinly coated GRCop-84 specimens were similar to the uncoated specimens within the limits of experimental scatter. It is concluded that the cold sprayed CuCrAl coating is suitable for protecting GRCop-84 substrates.

  20. Dynamic material property of the sinter-forged Cu-Cr alloys with the variation of chrome content

    International Nuclear Information System (INIS)

    Vacuum interrupters are used in various switch-gear components such as circuit breakers, distribution switches, contactors. The electrodes of a vacuum interrupter are manufactured of sinter-forged Cu-Cr material for good electrical and mechanical characteristics. Since the closing velocity is 1∼2m/s and impact deformation of the electrode depends on the strain-rate at the given velocity, the dynamic material property of the sinter-forged Cu-Cr alloy is important to design the vacuum interrupter reliably and to identify the impact characteristics of a vacuum interrupter accurately. This paper is concerned with the dynamic material properties of sinter-forged Cu-Cr alloy for various strain rates. The amount of chrome is varied from 10 wt% to 30 wt% in order to investigate the influence of the chrome content on the dynamic material property. The high speed tensile test machine is utilized in order to identify the dynamic property of the Cu-Cr alloy at the intermediate strain-rate and the split Hopkinson pressure bar is used at the high strain-rate. Experimental results from both the quasi-static and the high strain-rate up to the 5000 /sec are interpolated with respect to the amount of chrome in order to construct the Johnson-Cook and the modified Johnson-Cook model as the constitutive relation that should be applied to numerical simulation of the impact behavior of electrodes

  1. Nano-scratching and nano-machining in different environments on Cr2N/Cu multilayer thin films

    International Nuclear Information System (INIS)

    Five nanostructured Cr2N/Cu multilayer coatings were deposited by a bipolar asymmetric reactive pulsed DC magnetron sputtering system, and various bilayer periods (Λ) were achieved by controlling the holding time of Si substrates in the plasma of Cr or Cu. The hardness and elastic modulus of multilayer coatings were investigated by means of a nanoindenter. Nano-scratch and nano machining experiments on multilayered coatings were conducted using atomic force microscopy (AFM) in air and DI-water, respectively. According to the groove depth, width, and coefficient of friction (COF) obtained from nano-scratch tests, influences of scratch cycle numbers and bilayer periods on the scratchability of Cr2N/Cu multilayered thin films were examined. It was observed that after nano-scratch experiments in air and water, the COF values and the amount of removed material increased with increasing bilayer period. After nano-machining tests in air and water, different types of the cutting chip pile-ups were observed. In this work, the surface tribological properties and machinability of Cr2N/Cu multilayered thin films when using an AFM are discussed.

  2. Electrokinetic enhancement on phytoremediation in Zn, Pb, Cu and Cd contaminated soil using potato plants.

    Science.gov (United States)

    Aboughalma, Hanssan; Bi, Ran; Schlaak, Michael

    2008-07-01

    The use of a combination of electrokinetic remediation and phytoremediation to decontaminate soil polluted with heavy metals has been demonstrated in a laboratory-scale experiment. Potato tubers were planted in plastic vessels filled with Zn, Pb, Cu and Cd contaminated soil and grown in a greenhouse. Three of these vessels were treated with direct current electric field (DC), three with alternative current (AC) and three remained untreated as control vessels. The soil pH varied from anode to cathode with a minimum of pH 3 near the anode and a maximum of pH 8 near the cathode in the DC treated soil profile. There was an accumulation of Zn, Cu and Cd at about 12 cm distance from anode when soil pH was 5 in the DC treated soil profile. There was no significant metal redistribution and pH variation between anode and cathode in the AC soil profile. The biomass production of the plants was 72% higher under AC treatment and 27% lower under DC treatment compared to the control. Metal accumulation was generally higher in the plant roots treated with electrical fields than the control. The overall metal uptake in plant shoots was lower under DC treatment compared to AC treatment and control, although there was a higher accumulation of Zn and Cu in the plant roots treated with electrical fields. The Zn uptake in plant shoots under AC treatment was higher compared to the control and DC treatment. Zn and Cu accumulation in the plant roots under AC and DC treatment was similar, and both were higher comparing to control. Cd content in plant roots under all three treatments was found to be higher than that in the soil. The Pb accumulation in the roots and the uptake into the shoots was lower compared to its content in the soil. PMID:18569305

  3. Dynamic off-centering of Cr$^{3+}$ ions and short-range magneto-electric clusters in in CdCr$_2$S$_4$

    CERN Document Server

    Oliveira, Gonçalo Nuno; Lopes, Armandina Lima; Amaral, João Sequeira; dos Santos, António; Ren, Yan; Mendonca, Tania Manuela; Sousa, Célia Tavares; Amaral, Vitor Sequeira; Correia, João Guilherme; Araújo, João Pedro

    2012-01-01

    The cubic spinel CdCr$_2$S$_4$ gained recently a vivid interest, given the relevance of relaxor-like dielectric behavior in its paramagnetic phase. By a singular combination of local probe techniques namely Pair Distribution Function and Perturbed Angular Correlation we firmly establish that the Cr ion plays the central key role on this exotic phenomenon, namely through a dynamic off-centering displacement of its coordination sphere. We further show that this off centering of the magnetic Cr-ion gives rise to a peculiar entanglement between the polar and magnetic degrees of freedom, stabilizing, in the paramagnetic phase, short range magnetic clusters, clearly seen in ultra-low field susceptibility measurements. Moreover, the Landau theory is here used to demonstrate that a linear coupling between the magnetic and polar order parameters is sufficient to justify the appearance of magnetic cluster in paramagnetic phase of this compound. These results open insights on the hotly debated magnetic and polar interac...

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

    International Nuclear Information System (INIS)

    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

  5. The characteristics of two-phase 22Cr-6Ni-2Mo-1,5Cu cast steel

    Directory of Open Access Journals (Sweden)

    B. Kalandyk

    2008-12-01

    Full Text Available The paper discusses the effect of the casting wall thickness on the segregation of alloying elements in two-phase (F-A 22Cr-6Ni-2Mo-1,5Cu cast steel. The values of the distribution coefficient k0 for Cr, Mo, Si, and Ni, Mn, Cu in the cast stepped test piece walls of three different thicknesses were determined. After solutioning, the values of Rm, R0,2, A5 and Z were measured in the wall of 45 mm thickness and were compared with the results obtained for austenitic cast steel of 18Cr-9Ni grade. In the examined cast steel also the content of δ ferrite and the value of PREN were determined.

  6. Transformation of centers of red and infrared luminescence under electron irradiation and annealing of CdS and CdS : Cu single crystals

    International Nuclear Information System (INIS)

    The luminescence centers of specially nonalloyed and alloyed with copper CdS monocrystals and their transformation under electron irradiation are studied. The Cu atoms, interacting basically with defects in the cadmium sublattice, form the CuCd centers, responsible for luminescence by the wave lengths λm = 0.98 μm. Transformation of defects complexes, responsible for the bands of green (λm = 0.541 μm), red (λm = 0.72 μm) and infrared (λm = 0.98 μm) luminescence, occurs at the annealing temperature above 50 deg C due to the increase in the mobility of point defects both in the CdS : Cu cadmium and sulfuric sublattices

  7. Conversion of red and infrared luminescence centers as a result of electron bombardment and annealing of CdS and CdS:Cu single crystals

    International Nuclear Information System (INIS)

    The luminescence centers and their conversion as a result of electron bombardment and annealing in CdS single crystals which were not specially doped and which were doped with copper have been investigated. The Cu atoms, which interact mainly with defects in the cadmium sublattice, form CuCd, which are responsible for luminescence at wavelengths λm=0.98-1.00 μm. At annealing temperatures above 50 deg. C, conversion of the defect complexes, which are responsible for the green (λm=0.514 μm), red (λm=0.72μm), and infrared (λm=0.98 μm) luminescence, occurs as a result of an increase in the mobility of point defects in the cadmium and sulfur sublattices of CdS:Cu

  8. Crystal structure and EPR studies of (cinchonineH 2) 2(CdCl 4)(Cd/CuCl 4) crystals with thermochromic and Jahn-Teller effect

    Science.gov (United States)

    Wesełucha-Birczyńska, A.; Oleksyn, B. J.; Śliwiński, J.; Goslar, J.; Hilczer, W.; Hoffmann, S. K.

    2005-09-01

    The crystal structure of (C 19H 24N 2O 2+) 2(CdCl 4) 2-(Cd 0.5Cu 0.5Cl 4) 2- has been determined by X-ray diffraction at 295 K. The compound crystallises in orthorhombic P2 12 12 1 space group with unit cell parameters: a=12.7381(10), b=13.5394(10), c=25.6520(10) Å, and Z=4. Packing of molecules in the unit cell is determined by single and bifurcated hydrogen bonds between cinchoninium cation, (cinchonineH 2) 2+, CuCl42- and CdCl42- tetrahedral anions. Specific feature of the packing is a partial stacking of the quinoline rings of adjacent cinchoninium cations. There are eight sites for M=Cd or Cu in the crystal unit cell. In the four of them the CdCl 4 tetrahedra are located. In the others Cd or Cu can be located and an average geometry (Cd/CuCl 4) is described by the X-ray diffraction data. EPR allows to observe only the CuCl 4 complexes and we have proved that there is not a random distribution of individual Cd and Cu among the (Cd/CuCl 4) sites but they are coupled in dimers, so that asymmetric unit can be identified as (cinchonineH 2·MeCl 4) 2 moiety. Specific feature of the structure is that CuCl 4 tetrahedra are relatively weakly deformed from ideal tetrahedral geometry Td towards the D2 d symmetry (flattening angle 123.3°) and have relatively long Cu-Cl bonds (2.338 Å) at 295 K. Reflectance optical absorption band at 8700 cm -1 with a shoulder at 6200 cm -1 are assigned to ( x2- y2)→( z2) and ( x2- y2)→( xy) transitions, and they follow the well-known relationship between band positions and geometry of tetrachlorocuprates. EPR shows that the exchange coupling between Cu 2+ ions is very weak and an individual CuCl 4 gives separate lines in EPR spectrum. The spectrum below 200 K is characterised with parameters gx=2.047, gy=2.127, and gz=2.404 and above this temperature becomes dynamically averaged to g∥=2.299 and g⊥=2.065. This continuous type transition to the dynamic phase, without a thermal effect, is accompanied by the change in the crystal

  9. Radiation processes in CdIn2S4 and CdIn2(1-x)Cr2xS4 monocrystals

    International Nuclear Information System (INIS)

    Results of studying luminescence of CdIn2S4 monocrystals, specially unalloyed and alloyed with chromium, are presented. Elementary components, forming integral spectrum, are isolated, energies of their maxima are determined. Nature of radiative recombination centers is ascertained, energy diagram of local levels is suggested. Criteria, permitting to estimate the degree of position disorder in cation sublattice, connected with partial inversion of spinel structure of the investigated crystals are found. Features of experimental methods of studying intracentral radiation of CdIn2S4: Cr monocrystals are considered. 83 refs.; 25 figs.; 1 tab

  10. New method for computer analysis of complex intermetallic compounds and nanocluster model of the samson phase Cd3Cu4

    International Nuclear Information System (INIS)

    A new method is proposed for the computer analysis of crystal structures of complex intermetallic compounds (with more than 1000 atoms per unit cell) using a developed algorithm of the complete decomposition of the 3D graph of the structure into nanocluster substructures. This method has been implemented in the TOPOS software package and approved successfully in an analysis of the complex Cu3Cd4 structure (Samson phase). Cu3Cd4 structure models were used to establish a structural relationship between nanoclusters in this intermetallic compound and nanoclusters in other complex crystal structures: ZrZn22, Ru7Mg44, NaCd2, and Mg2Al3.

  11. Orange-red luminescence from Cu doped CdS nanophosphor prepared using mixed Langmuir-Blodgett multilayers.

    Science.gov (United States)

    Mandal, P; Talwar, S S; Major, S S; Srinivasa, R S

    2008-03-21

    Cu doped CdS nanophosphors were fabricated through Langmuir-Blodgett route for the first time. Precursors mixed Langmuir-Blodgett multilayers of cadmium arachidate-copper arachidate were used to grow doped sulfide nanoparticles within the organic matrix through postdeposition treatment with H(2)S gas. Changes in composition and layered structure of precursor multilayers were studied using Fourier transform infrared and x-ray reflection. Uptake of Cu in the multilayers was analyzed by inductively coupled plasma atomic emission spectroscopy measurements. Unannealed H(2)S exposed multilayers containing CdS nanoparticles show strong surface state emission centered at approximately 570 nm, whereas Cu doped CdS nanoparticles show orange-red luminescence. Photoluminescence (PL) spectra of annealed-Cu doped CdS nanoparticles show distinct Cu-related emission compared to annealed-undoped CdS nanoparticles. Power dependent PL measurements of annealed samples show that an efficient carrier recombination takes place at T(2) level of Cu(++). The carrier relaxation from the excitonic states to T(2) level results in the strong orange-red luminescence. PMID:18361597

  12. Kinetics and equilibrium studies for sorption of Cu(II) and Cr(Vi) Ions onto polymeric composite resins

    International Nuclear Information System (INIS)

    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, presence of complexing agent, effect of sorbent dosage and ionic strength. Kinetic parameters as a function of initial ion concentration were determined to predict the sorption behavior of Cu(Il) and Cr(Vi) onto polymeric composite resins. The equilibrium data could be fitted by the Freundlich adsorption isotherm equation. Industrial and mining waste water are important sources of heavy metals pollution (Quek et al, 1998). Chromium compounds are widely used by modern industries, resulting in large quantities of this element being discharged into the environment. Some of the main uses of chromium compounds are: plastic coating of surfaces, electroplating of metal, leather tanning and finishing, and in pigments and wood preservative (Korngold et al., 2003 and (Demirbas et al., 2004). Chromium occurs in waste water resulting from these operations is in both trivalent Cr(III) and hexavalent Cr(Vi) forms. The presence of Cu(II) in wastewater is also a problem. Copper is used extensively by electrical industries, in fungicides and in anti-fouling paints. When Cu is ingested at high concentrations, it become toxic to humans, causing cancer and promoting oxidation. The present method for removal of Cu(II) is to be precipitated as copper hydroxide by liming. However, with this process, residual Cu remains a problem (Findon et al, 1993). Owing to their wide uses, the efficient removal of toxic metal ions from waste water is an important and widely studied research area where a number of technologies have been developed over the years (Deans et al., 1992). The most important of these methods are filtration, chemical precipitation, ion exchange, sorption, electrodeposition and membrane systems. All these approaches have their inherent advantages and limitations

  13. 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. PMID:25960271

  14. Preparation of Cd(Zn)Te and CuInSe sub 2 films and devices by a two-stage process

    Energy Technology Data Exchange (ETDEWEB)

    Basol, B.M.; Kapur, V.K. (International Solar Electric Technology (ISET), Inglewood, CA (USA))

    1991-05-01

    The two-stage process was used to prepare thin films of Cd(Zn)Te and CuInSe{sub 2}. The technique involves first depositing the elemental components of the compound onto a substrate in the form of thin stacked layers and then reacting these elemental components to obtain a thin film of the desired compound. While CdTe films grown on thin CdS layers have uniform stoichiometries and sharp interfaces with the underlying CdS layers, CdZnTe films deposited onto similar substrates give rise to diffused CdZnTe-CdS interfaces because of the reactive nature of zinc. In CuInSe{sub 2} processing, the nature of the reacted compound film strongly depends on the nature of the Cu-In layers. CdS/CuInSe{sub 2} device efficiencies are also influenced by the method of deposition for the CdS window layers. (orig.).

  15. (Ca/Sr)AuxCd1-x: Stacking variants of the CrB-FeB series

    International Nuclear Information System (INIS)

    The structural chemistry of binary 1:1 alkaline earth metallides AIIM (M=p-block or late transition element) is dominated by planar M zig-zag chains, which are stacked in different orientations (CrB (c) to FeB (h) type) and with variable stacking distances (types I and II). As a case study of the electronic influences, the substitution of Au against Cd in the respective Ca and Sr aurides was examined by means of experimental, crystallographic and computational methods. Starting from CaAu, up to 11% of Au can be substituted by Cd without a change in the CrB structure type (orthorhombic, space group Cmcm, a=398.2(1), b=1122.6(6), c=460.9(2)pm, Z=4, R1=0.0303). Starting from SrAu (stacking sequence (hc)2(h2c)2), depending on the proportion of the Cd substitution a successive change to structures with increased hexagonality is observed: In SrAu0.93Cd0.07 (monoclinic, space group P21/m, a=621.3(4), b=472.4(2), c=1216.1(9)pm, β=96.97(5)0, Z=6, R1=0.0467) the stacking sequence is h2c, i.e. the hexagonality is 66.67%. A slightly more increased Cd content in SrAu0.78Cd0.22 (orthorhombic, space group Pnma, a=3243.3(8), b=474.17(8), c=626.20(9)pm, Z=16, R1=0.0682) drives the hexagonality to 75%, with a (h3c)2 stacking sequence known from several rare earth nickel compounds. Further Cd substitution is not possible. However, in the Cd-rich section of the two series, where the CsCl/β-brass structure type occurs for both alkaline earth elements, a small Au substitution, as determined from powder data by Rietveld refinements, is possible. The substitution limit and the stability ranges of the CsCl and the CrB type can be rationalized from the calculated band structures. Geometrical and electronic criteria are used to compare and discuss the stability ranges in a structural map. - SrAu0.93Cd0.97, one of the stacking sequences of the CrB/FeB structure type series found in the quasibinary section SrAu-SrCd.

  16. RELATIONSHIPS BETWEEN FRACTIONATIONS OF Pb, Cd, Cu, Zn AND Ni AND SOIL PROPERTIES IN URBAN SOILS OF CHANGCHUN, CHINA

    Institute of Scientific and Technical Information of China (English)

    GUO Ping; XIE Zhong-lei; LI Jun; KANG Chun-li; LIU Jian-hua

    2005-01-01

    An extensive soil investigation was conducted in different domains of Changchun to disclose the fractionations of Pb, Cu, Cd, Zn and Ni in urban soils. Meanwhile correlation analysis and multiple stepwise regressions were used to define relationships between soil properties and metal fractions and the chief factors influencingthe fractionation of heavy metals in the soils. The results showed that Pb, Ni and Cu were mainly associated with the residual and organic forms; most of Cd was concentrated in the residual and exchangeable fractions. Zn in residual and carbonate fraction was the highest. The activities of the heavy metals probably declined in the following order: Cd, Zn,Pb, CuandNi. The chemical fractions of heavy metals in different domains in Changchun City were of significantly spatial heterogeneity. Soil properties had different influences on the chemical fractions of heavy metals to some extent and the main factors influencing Cd, Zn, Pb, Cu and Ni fractionation and transformation were apparently different.

  17. Synthesis of zeolite-supported microscale zero-valent iron for the removal of Cr(6+) and Cd(2+) from aqueous solution.

    Science.gov (United States)

    Kong, Xiangke; Han, Zhantao; Zhang, Wei; Song, Le; Li, Hui

    2016-03-15

    Zeolite-supported microscale zero-valent iron (Z-mZVI) was synthesized and used to remove heavy metal cation (Cd(2+)) and anion (Cr(6+)) from aqueous solution. Transmission electron microscope (TEM) confirmed that mZVI (100-200 nm) has been successfully loaded and efficiently dispersed on zeolite. Atomic absorption Spectroscopy (AAS) revealed the amount of stabilized mZVI was about 1.3 wt.%. The synthesized Z-mZVI has much higher reduction ability and adsorption capacity for Cr(6+) and Cd(2+) compared to bare nanoscale zero-valent iron (nZVI) and zeolite. Above 77% Cr(6+) and 99% Cd(2+) were removed by Z-mZVI, while only 45% Cr(6+) and 9% Cd(2+) were removed by the same amount iron of nZVI, and 1% Cr(6+) and 39% Cd(2+) were removed by zeolite alone with an initial concentration of 20 mg/L Cr(6+) and 200 mg/L Cd(2+). The removal of Cr(6+) by Z-mZVI follows the pseudo first-order kinetics model, and X-ray photoelectron spectroscopy (XPS) analysis confirmed that Cr(6+) was reduced to Cr(3+) and immobilized on the surface of Z-mZVI. The removal mechanisms for Cr(6+) include reduction, adsorption of Cr(3+) hydroxides and/or mixed Fe(3+)/Cr(3+) (oxy)hydroxides. The pseudo-second-order kinetic model indicated that chemical sorption might be rate-limiting in the sorption of Cd(2+) by Z-mZVI. This synthesized Z-mZVI has shown the potential as an efficient and promising reactive material for removing various heavy metals from wastewater or polluted groundwater. PMID:26731307

  18. Growth and structure of CrN nanoislands on Cu(001) studied by scanning tunneling microscopy and X-ray photoemission spectroscopy

    International Nuclear Information System (INIS)

    We report a method for the fabrication of high structural quality CrN nanoislands on Cu(001). The CrN nanoislands can be fabricated in ultrahigh vacuum conditions by means of Cr atoms deposition on saturated Cu(001)c(2 × 2)-N surface and subsequent annealing at 500 °C. Existence of two types of nanoislands is shown by scanning tunneling microscopy investigations with atomic resolution for different CrN nanoislands formed on surface with 0.35 monolayer Cr coverage. The measured in-plane lattice constant (a = 0.39 ± 0.01 nm) of the CrN nanoislands is 8% larger than the Cu substrate lattice. X-ray photoemission spectroscopy investigations reveal chromium nitride phase transition from CrN to Cr2N associated with changes of Cr concentration. - Highlights: ► We develop a method for the fabrication of CrN nanoislands on Cu(001). ► Growth of two types of CrN nanoislands is shown by scanning tunneling microscopy. ► Chromium nitride phase transition is shown by X-ray photoemission spectroscopy

  19. 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.

  20. Heavy metal content (Cd, Ni, Cr and Pb) in soil amendment with a low polluted biosolid

    Science.gov (United States)

    Gomez Lucas, Ignacio; Lag Brotons, Alfonso; Navarro-Pedreño, Jose; Belén Almendro-Candel, Maria; Jordán, Manuel M.; Bech, Jaume; Roca, Nuria

    2016-04-01

    The progressively higher water quality standards in Europe has led to the generation of large quantities of sewage sludge derived from wastewater treatment (Fytili and Zabaniotou 2008). Composting is an effective method to minimize these risks, as pathogens are biodegraded and heavy metals are stabilized as a result of organic matter transformations (Barker and Bryson 2002; Noble and Roberts 2004). Most of the studies about sewage sludge pollution are centred in medium and high polluted wastes. However, the aim of this study was to assess the effects on soil heavy metal content of a low polluted sewage sludge compost in order to identify an optimal application rate based in heavy metal concentration under a period of cultivation of a Mediterranean horticultural plant (Cynara carducnculus). The experiment was done between January to June: rainfall was 71 mm, the volume of water supplied every week was 10.5 mm, mean air temperatures was 14.2, 20.4 (maximum), and 9.2◦C (minimum). The soil was a clay-loam anthrosol (WRB 2006). The experimental plot (60 m2) was divided into five subplots with five treatments corresponding to 0, 2, 4, 6, and 8 kg compost/m2. Three top-soil (first 20 cm) samples from each treatment were taken (January, April and June) and these parameters were analysed: pH, electrical conductivity, organic matter and total content of heavy metals (microwave acid digestion followed by AAS-spectrometry determination). The results show that sewage sludge compost treatments increase the organic matter content and salinity (electrical conductivity of the soils) and diminish the pH. Cd and Ni total content in top-soil was affected and both slightly reduce their concentration. Pb and Cr show minor changes. In general, the application of this low polluted compost may affect the mobility of Cd and Ni due to the pH modification and the water added by irrigation along time but Pb and Cr remain their content in the top-soil. References Barker, A.V., and G.M. Bryson

  1. Paramagnetism in the kagome compounds (Zn ,Mg ,Cd ) Cu3(OH) 6Cl2

    Science.gov (United States)

    Iqbal, Yasir; Jeschke, Harald O.; Reuther, Johannes; Valentí, Roser; Mazin, I. I.; Greiter, Martin; Thomale, Ronny

    2015-12-01

    Frustrated magnetism on the kagome lattice has been a fertile ground for rich and fascinating physics, ranging from experimental evidence of a spin liquid to theoretical predictions of exotic superconductivity. Among experimentally realized spin-1/2 kagome magnets, herbertsmithite, kapellasite, and haydeeite [(Zn ,Mg ) Cu3(OH) 6Cl2] are all well described by a three-parameter Heisenberg model, but they exhibit distinctly different physics. We address the problem using a pseudofermion functional renormalization-group approach and analyze the low-energy physics in the experimentally accessible parameter range. Our analysis places kapellasite and haydeeite near the boundaries between magnetically ordered and disordered phases, implying that slight modifications could dramatically affect their magnetic properties. Inspired by this, we perform ab initio density functional theory calculations of (Zn,Mg,Cd ) Cu3 (OH) 6Cl2 at various pressures. Our results suggest that by varying pressure and composition one can traverse a paramagnetic regime between different magnetically ordered phases.

  2. Size effect on the SHG properties of Cu-doped CdI2 nanocrystals

    International Nuclear Information System (INIS)

    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 CdI2 layered nanocrystal structures from the mixture of CdI2 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 CdI2 layered nanocrystals are promising materials for applications in optoelectronic nano-devices.

  3. Cyclic Oxidation Behavior of Cold Sprayed CuCrAl-Coated and Uncoated GRCop-84 Substrates for Space Launch Vehicles

    Science.gov (United States)

    Raj, S. V.; Barrett, C.; Karthikeyan, J.; Garlick, R.

    2006-01-01

    A newly developed Cu-23 (wt %) Cr-5%Al (CuCrAl) alloy shown to resist hydridation and oxidation in an as-cast form is currently being considered as a protective coating for GRCop-84, which is an advanced copper alloy containing 8 (at.%) Cr and 4 (at.%) Nb. The coating was deposited on GRCop-84 substrates by the cold spray deposition technique. Cyclic oxidation tests conducted in air on both coated and uncoated substrates between 773 and 1073 K revealed that the coating remained intact and protected the substrate up to 1073 K. No significant weight loss of the coated specimens were observed at 773 and 873 K even after a cumulative cyclic time of 500 h. About a 10 percent weight loss observed at 973 and 1073 K was attributed to the excessive oxidation of the uncoated sides. In contrast, the uncoated substrate lost as much as 80 percent of its original weight under similar test conditions. It is concluded that the cold sprayed CuCrAl coating is suitable for protecting GRCop-84 substrates.

  4. Evaluation of fly ashes for the removal of cu, ni and cd from acidic waters

    OpenAIRE

    FERNÁNDEZ PÉREZ, BEGOÑA; AYALA ESPINA, JULIA

    2010-01-01

    The presence of sulphides in many mine wastes and the formation of acid mine drainages (AMD) has been widely recognized as one of the great environmental problems nowadays. Waters from many of the abandoned mines, with thousands of cubic meters of residue scattered in dumps and ponds, are affected by this type of pollution characterized by its acidity, high contents of sulphates and heavy metals such as Fe, Mn, Al, Cu, Ni, Cd. This study was designed to study the effect of use flying ash ...

  5. ELECTROOXIDATION OF METHANOL ON PT MODIFIED WITH ADATOMS (NI, CU, PB, CD)

    OpenAIRE

    A.Khouchaf; D. Takky; M. E1 M. Chbihi; S. Benmokhtar

    2015-01-01

    The electro oxidation of methanol has been studied in alkaline medium NaOH 0.1 M and acid medium H2SO4 0.5 M on a platinum electrode and a platinum modified by adatom adsorption (Ni, Cu, Pb, and Cd). The influence of different experimental variables (methanol concentration, and temperature) is reported. Preliminary investigations by cyclic voltammetry showed that the catalytic activity of platinum is still too low to be considered as a practical catalyst. Underpotential deposition of lead, ni...

  6. ELECTROOXIDATION OF METHANOL ON PT MODIFIED WITH ADATOMS (NI, CU, PB, CD

    Directory of Open Access Journals (Sweden)

    A.Khouchaf

    2015-05-01

    Full Text Available The electro oxidation of methanol has been studied in alkaline medium NaOH 0.1 M and acid medium H2SO4 0.5 M on a platinum electrode and a platinum modified by adatom adsorption (Ni, Cu, Pb, and Cd. The influence of different experimental variables (methanol concentration, and temperature is reported. Preliminary investigations by cyclic voltammetry showed that the catalytic activity of platinum is still too low to be considered as a practical catalyst. Underpotential deposition of lead, nickel, cadmium, or copper adatoms at platinum allowed increasing significantly the current densities.

  7. Diffusion-Reaction Modeling of Cu Migration in CdTe Solar Devices

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Da [Arizona State Univ., Tempe, AZ (United States); Brinkman, Daniel [Arizona State Univ., Tempe, AZ (United States); Fang, Tian [First Solar Inc.; Akis, Richard [Arizona State Univ., Tempe, AZ (United States); Sankin, Igor [First Solar Inc.; Vasileska, Dragica [Arizona State Univ., Tempe, AZ (United States); Ringhofer, Christian [Arizona State Univ., Tempe, AZ (United States)

    2015-09-04

    In this work, we report on development of one-dimensional (1D) finite-difference and two-dimensional (2D) finite-element diffusion-reaction simulators to investigate mechanisms behind Cu-related metastabilities observed in CdTe solar cells [1]. The evolution of CdTe solar cells performance has been studied as a function of stress time in response to the evolution of associated acceptor and donor states. To achieve such capability, the simu-lators solve reaction-diffusion equations for the defect states in time-space domain self-consistently with the free carrier transport. Re-sults of 1-D and 2-D simulations have been compared to verify the accuracy of solutions.

  8. Cu-doped Cd1- x Zn x S alloy: synthesis and structural investigations

    Science.gov (United States)

    Yadav, Indu; Ahlawat, Dharamvir Singh; Ahlawat, Rachna

    2016-03-01

    Copper doped Cd1- x Zn x S ( x ≤ 1) quantum dots have been synthesized using chemical co-precipitation method. Structural investigation of the synthesized nanomaterials has been carried out by powder XRD method. The XRD results have confirmed that as-prepared Cu-doped Cd1- x Zn x S quantum dots have hexagonal structure. The average nanocrystallite size was estimated in the range 2-12 nm using Debye-Scherrer formula. The lattice constants, lattice plane, d-spacing, unit cell volume, Lorentz factor and dislocation density were also calculated from XRD data. The change in particle size was observed with the change in Zn concentration. Furthermore, FTIR spectra of the prepared samples were observed for identification of COO- and O-H functional groups. The TEM study has also reported the same size range of nanoparticles. The increase in agglomeration has been observed with the increase in Zn concentration in the prepared samples.

  9. Cu-doped Cd1-xZnxS alloy: synthesis and structural investigations

    International Nuclear Information System (INIS)

    Copper doped Cd1-xZnxS (x ≤ 1) quantum dots have been synthesized using chemical co-precipitation method. Structural investigation of the synthesized nanomaterials has been carried out by powder XRD method. The XRD results have confirmed that as-prepared Cu-doped Cd1-xZnxS quantum dots have hexagonal structure. The average nanocrystallite size was estimated in the range 2-12 nm using Debye-Scherrer formula. The lattice constants, lattice plane, d-spacing, unit cell volume, Lorentz factor and dislocation density were also calculated from XRD data. The change in particle size was observed with the change in Zn concentration. Furthermore, FTIR spectra of the prepared samples were observed for identification of COO- and O-H functional groups. The TEM study has also reported the same size range of nanoparticles. The increase in agglomeration has been observed with the increase in Zn concentration in the prepared samples. (orig.)

  10. Temperature dependent lattice instability in single crystals of ferromagnetic CdCr2Se4 diluted with In and Sb

    International Nuclear Information System (INIS)

    In ferromagnetic CdCr2Se4 diluted with Mex3+ = In and Sb, deviations from cubic symmetry Fd3-barm appear in the paramagnetic phase just below room temperature, and they increase with decreasing temperature. For Sb admixture, the unit-cell anomalies indicate a structural phase transition to occur at the same temperature as the magnetic transition, Tc = 130 K, which also is the same Tc as for the parent crystal CdCr2Se4. The low temperature phase has been described in orthorhombic space group Fddd. For In admixture, a structural transition occurs in the paramagnetic state at about Ta∼200 K (which is higher than Tc = 125 K), to a tetragonal structure with space group I41/amd. This behaviour is attributed to macroscopic spontaneous strain due to chemical heterogeneities, and to spin frustrations due to mixed valencies of Cr. The paramagnetic Curie-Weiss temperature θC-W decreases for both admixtures, indicating changes in competing ferromagnetic and antiferromagnetic interactions. The magnetization at 2.1 K exhibits saturation for H>0.6 T. The magnetic moments are μsat = 6.26 and 5.47 μB mol-1 for Sb and In admixtures, respectively. These values are consistent with the Cr3+ and Cr2+ mixed valencies, and with the proposed cation distribution model. A spin-phonon coupling of the transitions in the crystal with Sb admixture is suggested, while such a correspondence is not clear for the In admixture.

  11. 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. PMID:26354691

  12. Microstructure and Properties of CuCr50 Processed by Laser Surface Treatment%激光表面处理CuCr50合金的显微组织及性能

    Institute of Scientific and Technical Information of China (English)

    刘杰; 周志明; 涂坚; 黄灿; 柴林江; 黄伟九; 王亚平

    2016-01-01

    目的:细化CuCr50合金的Cr相组织,提高组织均匀性。方法采用Nd:YAG脉冲激光器对CuCr50合金进行表面处理,并对激光处理后合金的显微组织(表面组织和截面组织)、导电性能、显微硬度、耐磨性等进行测试与分析。结果工艺优化后得到的实验参数为:激光功率500 W,峰值5.0 kW,扫描速度4 mm/s,激光频率6 Hz,激光脉宽5 ms,离焦量为+4 mm。在优化的工艺条件下,CuCr50合金经激光表面处理后,形成了致密的重熔层,Cr相的晶粒得到明显细化,合金的组织均匀性提高,表面孔洞减少。合金重熔层中的相组成未发生变化,合金的导电性略微降低,但仍保持了CuCr50合金优良的导电性能。重熔层显微硬度(425~540HV)明显提高,最高硬度为540HV,是基体显微硬度(约240HV)的2.25倍。重熔层的摩擦系数(0.3)远低于原始CuCr50合金(0.45),重熔层的损失质量(0.15 mg)远小于原始CuCr50合金的损失质量(0.6 mg),合金的耐磨性有明显的提高。结论 CuCr50合金在优化的工艺参数条件下进行激光表面处理,能够细化Cr相组织和提高整个合金的组织均匀性,提高合金的显微硬度与耐磨性能。%ABSTRACT:Objective To refine the Cr phase structure of CuCr50 and improve the uniformity of the microstructure.Me-thodsCuCr50 alloys were treated by Nd:YAG pulsed laser, and the microstructure (surface microstructure and cross-section mi-crostructure), phase, electrical conductivity, microhardness and wear resistance of the alloy were investigated and analyzed after the laser treatment.Results Experimental parameters of process optimization were: laser power 500 W, peak 5.0 kW, scanning speed 4 mm/s, laser frequency 6 Hz, laser pulsed width 5 ms, defocus amount +4 mm. Under the optimized process conditions, dense remelting layer was formed, the size of Cr particles was significantly reduced, the structural

  13. Removal of Cd, Cu, Pb, and Zn from aqueous solutions by biochars.

    Science.gov (United States)

    Doumer, M E; Rigol, A; Vidal, M; Mangrich, A S

    2016-02-01

    Sorption and desorption of heavy metals (Cd, Cu, Pb, and Zn) was evaluated in biochars derived from sugarcane bagasse (SB), eucalyptus forest residues (CE), castor meal (CM), green coconut pericarp (PC), and water hyacinth (WH) as candidate materials for the treatment of contaminated waters and soils. Solid-liquid distribution coefficients depended strongly on the initial metal concentration, with K d,max values mostly within the range 10(3)-10(4) L kg(-1). For all biochars, up to 95 % removal of all the target metals from water was achieved. The WH biochar showed the highest K d,max values for all the metals, especially Cd and Zn, followed by CE (for Cd and Pb) and PC (for Cd, Pb, and Zn). Sorption data were fitted satisfactorily with Freundlich and linear models (in the latter case, for the low concentration range). The sorption appeared to be controlled by cationic exchange, together with specific surface complexation at low metal concentrations. The low desorption yields, generally less than 5 %, confirmed that the sorption process was largely irreversible and that the biochars could potentially be used in decontamination applications. PMID:26438367

  14. Electrochemical deposition and microstructural characterization of AlCrFeMnNi and AlCrCuFeMnNi high entropy alloy thin films

    Science.gov (United States)

    Soare, V.; Burada, M.; Constantin, I.; Mitrică, D.; Bădiliţă, V.; Caragea, A.; Târcolea, M.

    2015-12-01

    Al-Cr-Fe-Mn-Ni and Al-Cr-Cu-Fe-Mn-Ni high entropy alloy thin films were prepared by potentiostatic electrodeposition and the microstructure of the deposits was investigated. The thin films were co-deposited in an electrolyte based on a DMF (N,N-dimethylformamide)-CH3CN (acetonitrile) organic compound. The energy dispersive spectrometry investigation (EDS) indicated that all the five respectively six elements were successfully co-deposited. The scanning electron microscopy (SEM) analysis revealed that the film consists of compact and uniform particles with particle sizes of 500 nm to 4 μm. The X-ray diffractometry (XRD) patterns indicated that the as-deposited thin films were amorphous. Body-centered-cubic (BCC) structures were identified by XRD after the films were annealed at various temperatures under inert Ar atmosphere. The alloys adhesion on the substrate was determined by the scratch-testing method, with higher values obtained for the Al-Cr-Cu-Fe-Mn-Ni alloy.

  15. Effect of hydrostatic pressure on the structural and electronic properties of Cd0.75Cr0.25S

    Science.gov (United States)

    Rani, Anita; Kaur, Kulwinder; Dhiman, Shobna; Kumar, Ranjan

    2016-05-01

    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 Cd1-xCrxS diluted magnetic semiconductor in Zinc Blende (B3) phase at x=0.25. High pressure behavior of Cd1-xCrxS has been investigated between 0 GPa to100 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 Cd1-xCrxS are discussed in terms of contribution of Cr 3d5 4s1, Cd 4d10 5s2, S 3s2 3p4 orbital's. Study of band structures shows half-metallic ferromagnetic nature of Cd0.75Cr0.25S 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

  16. High field magnetotransport and point contact Andreev reflection measurements on CuCr{sub 2}Se{sub 4} and CuCr{sub 2}Se{sub 3}Br—Degenerate magnetic semiconductor single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Borisov, K., E-mail: borisovk@tcd.ie; Coey, J. M. D.; Stamenov, P. [School of Physics and CRANN, Trinity College, Dublin 2 (Ireland); Alaria, J. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom)

    2014-05-07

    Single crystals of the metallically degenerate fully magnetic semiconductors CuCr{sub 2}Se{sub 4} and CuCr{sub 2}Se{sub 3}Br have been prepared by the Chemical Vapour Transport method, using either Se or Br as transport agents. The high-quality, millimetre-sized, octahedrally faceted, needle- and platelet-shaped crystals are characterised by means of high field magnetotransport (μ{sub 0}H≤ 14 T) and Point Contact Andreev Reflection. The relatively high spin polarisation observed |P|>0.56, together with the relatively low minority carrier effective mass of 0.25 m{sub e}, and long scattering time  10{sup −13} s, could poise these materials for integration in low- and close-to-room temperature minority injection bipolar heterojunction transistor demonstrations.

  17. Cu{sub 6}Te{sub 3}S. A Cu-filled Cr{sub 3}Si-structure variant

    Energy Technology Data Exchange (ETDEWEB)

    Giller, Malte; Grotz, Carolin; Nilges, Tom [Technische Universitaet Muenchen, Garching (Germany). Dept. of Chemistry; Rudyk, Brent W.; Mar, Arthur [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemistry

    2014-07-01

    A solid state melting and annealing route was used to prepare Cu{sub 6}Te{sub 3}S, a copper telluride sulfide representing a filled variant of the Cr{sub 3}Si structure type. The title compound exhibits a reversible phase transition at 404 K which was confirmed by thermal analysis, temperature dependent X-ray single crystal and powder diffractometry. Both polymorphs crystallize cubic in space groups P anti 43n and P2{sub 1}3, respectively. X-ray photoelectron spectroscopy (XPS) was performed to evaluate the electronic structure of Cu{sub 6}Te{sub 3}S and to determine the oxidation state of Cu in the title compound.

  18. Ni-Cr-B-Si+Cu-P-Sn复合钎料真空钎焊金刚石%Vacuum brazing diamond with Ni-Cr-B-Si+Cu-P-Sn composite filler metal

    Institute of Scientific and Technical Information of China (English)

    卢金斌; 贺亚勋; 张旺玺; 刘磊; 李华

    2016-01-01

    采用在镍基钎料中分别添加3%、5%和7%(质量分数)Cu-P-Sn组成新型复合钎料,并进行金刚石磨粒的钎焊实验,利用SEM、EDS和XRD对金刚石焊后的界面碳化物形貌及钎料组织进行测试分析。结果表明:添加5%Cu-P-Sn的复合钎料进行金刚石钎焊时,钎焊温度有所下降,金刚石表面碳化物较规整,并且数量有所下降,降低金刚石的热损伤。新型钎料中形成树枝晶α-Ni基固溶体和枝晶间Ni 31 Si 12、Cr 7 C 3等化合物的组织,不同含量Cu-P-Sn与Ni-Cr-B-Si合金可以较大程度互溶,可以实现钎料性能的调控,降低金刚石的热损伤。%A series of new composite brazing fillers metal were got by adding 3%, 5% or 7% (mass fraction) Cu-P-Sn in the primary brazing filler metal Ni-Cr-B-Si, respectively, then, they were used to braze diamond particles. The interface morphology of diamond carbide and the microstructure of brazing filler metal were tested by SEM, EDS and XRD. The results show that, when the composite brazing filler metal containing 5% Cu-P-Sn alloy, the carbide on the surface of the diamond is more regular and less with brazing temperature decreases, which decreases the thermal damage to the diamond. In the brazing filler alloy, the microstructures, such as dentrite included solid solution of Ni with some carbides like Ni31Si12 and Cr7C3, are formed. As the added component, Cu-P-Sn at different proportions can be dissolved into the primary brazing filler Ni-Cr-B-Si in large degree, which can adjust the properties of the filler and reduce the heat damage to the diamond.

  19. Elastic properties of fcc Fe-Mn-X (X=Cr, Co, Ni, Cu) alloys from first-principles calculations

    OpenAIRE

    Reeh, S; Music, D; Ekholm, Marcus; Abrikosov, Igor; Schneider, J. M.

    2013-01-01

    The influence of the valence electron concentration of X in fcc Fe-Mn-X (X=Cr, Co, Ni, Cu) alloys on the elastic and magnetic properties has been studied by means of ab initio calculations for alloy element concentrations of up to 8 at. % X. We observe that Cu increases the bulk-to-shear modulus (B/G) ratio by 19.2%. Simultaneously magnetic moments of Fe and Mn increase strongly. The other alloying elements induce less significant changes in B/G. The trends in B/G may be understood by conside...

  20. Photoinduced increase of magnetization in the phase transition region in the ferromagnetic semiconductors CdCr2Se4 and HgCr2Se4

    International Nuclear Information System (INIS)

    The effect of radiation pulses from a parametric light generator (τ∼15ns, λ=0.66-2.7μm) on the magnetization of the magnetic semiconductors CdCr2Se4 and HgCr2Se4 containing small Ga additions has been investigated. An increase of the magnetization induced by light pulses from a parametric generator with a wavelength close to the optical absorption edge of the samples is observed at temperatures T≥Tk and in magnetic fields up to 6 kOe. It is suggested that the photoinduced enhancement of the magnetization mey be due an increase of the exchange interaction of the magnetic ions caused by photoexcited electrons localized near the Ga impurity atoms. For a light pulse energy density of about 10-2 Jcm-2 the increase of magnetization reached 6G; this corresponds to a shift of the Curie point by ∼ 1K toward higher temperatures

  1. Continuous-wave broadly tunable diode laser array-pumped mid-infrared Cr2+:CdSe laser

    Science.gov (United States)

    Lazarev, V. A.; Tarabrin, M. K.; Kovtun, A. A.; Karasik, V. E.; Kireev, A. N.; Kozlovsky, V. I.; Korostelin, Yu V.; Podmar'kov, Yu P.; Frolov, M. P.; Gubin, M. A.

    2015-12-01

    We demonstrate the operation of a room-temperature, solid-state, broadly tunable Cr-doped CdSe single-crystal continuous-wave laser. Longitudinal pumping with a continuous-wave diode laser array at 1.94 μm produced a broadband output of 280 mW at 2.6 μm with an incident power slope efficiency of 12%. With an intracavity Brewster-cut CaF2 prism, we tuned the Cr2+:CdSe laser from 2.45 to 3.06 μm with a resolution of 10 nm and an output power up to 55 mW.

  2. Determination of the transport parameters of nanocrystalline CdSe:Cu thin films

    International Nuclear Information System (INIS)

    Thin films of copper (Cu)-doped CdSe are prepared by the physical vapor deposition technique. X-ray diffraction analysis shows that the films crystallize in hexagonal structure with (100) as the preferred orientation. Scanning electron microscope studies reveal that the grains are spherical in shape and uniformly distributed all over the surface of the substrates. The transport properties of Cu-doped CdSe thin films have been investigated by the time-of-flight measurement, steady-state photocarrier grating and steady-state photoconductivity techniques. The temperature dependence of dark conductivity and photoconductivity data reflects the existence of two independent donor energy levels. The bimolecular recombination nature of the thin films has been found from the photocurrent-illumination dependence at different applied voltages. The minority carrier diffusion length (Ldiff) is obtained both from the best fit of the experimental photocurrent ratio β versus grating period (Λ) and from the ‘Balberg plot’. A straight line has been obtained from the best fit, which confirms that the measured length is the ambipolar diffusion length.

  3. Evaluation of fly ashes for the removal of Cu, Ni and Cd from acidic waters

    International Nuclear Information System (INIS)

    The presence of sulphides in many mine wastes and the formation of acid mine drainages (AMD) has been widely recognized as one of the great environmental problems nowadays. Waters from many of the abandoned mines, with thousands of cubic meters of residue scattered in dumps and ponds, are affected by this type of pollution characterized by its acidity, high contents of sulphates and heavy metals such as Fe, Mn, Al, Cu, Ni, Cd. This study was designed to study the effect of use flying ash coming from Power Stations as a neutralizer for acidic waters resulting from this type of abandoned facilities. In this study, and due to the heterogeneity of the contaminants present, we have studied the removal of Ni, Cu and Cd. Different parameters were studied: metal concentration and pH of the solution to be treated, time reaction and pulp density. Fly ash can be used as a neutralization/fixation agent. Fly ash will add alkalinity and increase the pH on contacting AMD. This will result in precipitation of metal hydroxides.

  4. Assessing Cd, Co, Cu, Ni, and Pb Sorption on montmorillonite using surface complexation models

    Energy Technology Data Exchange (ETDEWEB)

    Akafia, Martin M.; Reich, Thomas J. [Department of Geosciences, Western Michigan University, Kalamazoo, MI 49008 (United States); Koretsky, Carla M., E-mail: carla.koretsky@wmich.edu [Department of Geosciences, Western Michigan University, Kalamazoo, MI 49008 (United States)

    2011-06-15

    Highlights: > Cd, Co, Cu, Ni, and Pb sorption on montmorillonite is measured at 6 distinct conditions. > The data are used to develop a diffuse layer model with variable charge and fixed charge sites. > The DLM lacked the robustness to accurately predict adsorption at all conditions. - Abstract: Cadmium, Co, Cu, Ni and Pb adsorption is measured on montmorillonite as a function of pH (3-11), ionic strength (0.001-0.1 M NaNO{sub 3}), and sorbate concentration (0.1-10 {mu}M metal on 0.5 g/L solid). Sorption of all metals shows strong dependence on ionic strength and sorbate concentration, as well as a break in the slope of the edge, indicative of a 2-site interaction with montmorillonite. The resulting adsorption edges are used to parameterize diffuse layer surface complexation models (DLMs) for each metal. A 2-site DLM with a bidentate variable charge surface hydroxyl site and a bidentate permanent charge exchange site produced good fits for the individual experiments, but lacked the robustness to accurately predict adsorption across the entire experimental range. Other models, such as CCM, TLM, or CD-MUSIC may be required for more accurate predictions across broad ranges of solution conditions.

  5. Spatial distribution of dissolved Pb,Hg,Cd,Cu and As in the Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Characteristics of the spatial distribution of selected dissolved heavy metals were analyzed during large scale surveys from August 12 to 25.2003 in the Bohai Sea.Dissolved Pb was the only element with average concentrations higher than the grade-one sea water quality standard of China.The spatial distribution of dissolved Pb in surface water was similar to those of Cd,Cu and As,where the isopleths generally indicated decreasing values from the bays to the central areas.Only for Hg did the high concentrations not only appear in Liaodong Bay,Bohai Bay and Laizhou Bay,but also in the Central Area,viz.not only in inshore but also in offshore areas.Vertical distributions of dissolved Pb,Cd,Cu and As were largely uniform,while that of dissolved Hg increased with depth.We infer that the input of pollutants from land was the main influencing factor for the detected distribution patterns of dissolved heavy metals,followed by the dynamics of sea water,release from bottom sediments and biochemical processes.Comparing with historical data,average concentrations of dissolved heavy metals appear to decline in recent years.

  6. Multilayer mirrors on the basis of NiCu alloy for CuKα and CrKα lines radiation

    International Nuclear Information System (INIS)

    Results of research of optical and mechanical properties of multilayer X-ray mirrors on the basis of pair materials NiCu/B4C with the period 1.7-4.7 nm are presented. Nonmagnetic NiCu-alloy allows to increase stability of magnetron sputtering deposition and to reduce essentially the roughness value usually observed at deposition of Cu. Dependence of internal stresses in structure on its composition is presented

  7. Microstructure, thermodynamics and compressive properties of AlCoCrCuMn-x (x=Fe, Ti) high-entropy alloys

    International Nuclear Information System (INIS)

    Two equiatomic high-entropy alloys (HEAs), AlCoCrCuMnFe and AlCoCrCuMnTi, were produced by vacuum arc melting. Their microstructure, thermodynamics and mechanical properties were investigated in as-cast condition. The AlCoCrCuMnFe alloy is comprised of a face centered cubic (FCC) phase and two body centered cubic (BCC) phases, while the AlCoCrCuMnTi alloy consists of the intermetallics-base solid solution (AlCu2Mn-like phase) besides a FCC phase and two BCC phases. Through analyzing the thermodynamics of equiatomic multicomponent alloys, two parameters, kn and φ, were proposed. The parameter kn is a function of n (n – the number of the components in an alloy system), while φ is defined as a parameter of Tsum over |Hsum| (Tsum – the sum of every elemental melting point in an alloy system, |Hsum| – the sum of mixing enthalpies of different pairs of alloying elements). φ≥1.1/kn is equivalent to Ω≥1.1 proposed by Yang to predict high entropy stabilized solid solution in equiatomic multicomponent alloys and more convenient to calculate. Compressive properties of the two HEAs together with their hardness have been investigated. Comparing to AlCoCrCuMnFe alloy, AlCoCrCuMnTi alloy has higher Vickers hardness, yield strength and compressive strength, but lower ultimate strain

  8. Health Risk Assessment of Consumption of Tea marketed in Hamadan City, Potential Risk of As, Pb, Cd and Cr

    OpenAIRE

    S. Sobhan Ardakani; N. Aghelan

    2016-01-01

    Introduction & Objective: Tea is the most popular beverage in the world and contains several essential nutrients, which are beneficial for human health. Because the contamination of tea leaves by heavy metals may pose a serious threat to human, this study was carried out for analysis and health risk assessment of As, Pb, Cd and Cr in some black and green tea brand samples marketed in Hamadan City in 2015. Materials & Methods: After collection and preparation of 3 brands from each of culti...

  9. ACUTE TOXICITIES OF CD2+, CR+6, HG2+, NI2+, AND ZN2+ TO ESTUARINE MACROFAUNA

    Science.gov (United States)

    Static acute toxicity bioassays were conducted at 20 C and 20 o/oo salinity with CdCl2-2 and one half H2O, K2CrO4, HgCl2, NiCl2-6H2O, and ZnCl2 using adults of starfish, Asterias forbesi; sandworm, Nereis virens; hermit crab, Pagurus longicarpus; softshell clam, Mya arenaria; mud...

  10. Effects of Acute and Chronic Heavy Metal (Cu, Cd, and Zn) Exposure on Sea Cucumbers (Apostichopus japonicus).

    Science.gov (United States)

    Li, Li; Tian, Xiangli; Yu, Xiao; Dong, Shuanglin

    2016-01-01

    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. PMID:27382568

  11. Heavy metal (Cu, Zn, Cd and Pb) contamination of vegetables in urban India: A case study in Varanasi

    International Nuclear Information System (INIS)

    The contributions of heavy metals in selected vegetables through atmospheric deposition were quantified in an urban area of India. Deposition rate of Zn was recorded maximum followed by Cu, Cd and Pb. The concentrations of Zn and Cu were highest in Brassica oleracea, Cd in Abelmoschus esculentus and B. oleracea, while Pb was highest in Beta vulgaris. Heavy metal pollution index showed that B. oleracea was maximally contaminated with heavy metals followed by A. esculentus and then B. vulgaris. The results of washing showed that atmospheric deposition has contributed to the increased levels of heavy metals in vegetables. Both Cu and Cd posed health risk to local population via test vegetables consumption, whereas Pb posed the same only through B. oleracea. The study concludes that atmospheric depositions can elevate the levels of heavy metals in vegetables during marketing having potential health hazards to consumers. - Atmospheric depositions can significantly increase the heavy metal concentrations in vegetables during marketing

  12. High pressure high temperature (HPHT) synthesis and magnetism of Cr-12s2 copper oxides with fluorite-structured layers between CuO{sub 2} planes

    Energy Technology Data Exchange (ETDEWEB)

    Awana, V.P.S. [SMC, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110 012 (India)], E-mail: awana@mail.nplindia.ernet.in; Ubaldini, A.; Balamurugan, S. [SMC, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Kishan, H. [National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110 012 (India); Takayama-Muromachi, E. [SMC, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2007-09-01

    The three first members of the Cr-12s2 (s = 1, 2, 3) homologous series, i.e. CrSr{sub 2}YCu{sub 2}O{sub 8} (Cr-1212), CrSr{sub 2}(Y{sub 1.5}Ce{sub 0.5})Cu{sub 2}O{sub 10} (Cr-1222) and CrSr{sub 2}(Y{sub 1}Ce{sub 2})Cu{sub 2}O{sub 12}(Cr-1232) are synthesized by high pressure high temperature (HPHT) 6 GPa and 1550 deg. C process. Though the Cr-1212 and Cr-1232 could not be formed in single phase with full Cr, the Cr-1222 is achieved in pure phase with space group I4/mmm. These compounds belong to the multi-layered copper oxides series that differ from each other only in terms of the (Ce,Y)-[O{sub 2}-(Ce,Y)]{sub s-1} layer blocks between two identical CuO{sub 2} planes with s = 1, 2 and 3. At 5 K, the magnetization M(H) experiments showed some ferromagnetic like hysteresis loops though the characteristic M{sub r} and H{sub c} were not seen clearly. None of the studied compounds exhibited superconductivity down to 5 K.

  13. High pressure high temperature (HPHT) synthesis and magnetism of Cr-12s2 copper oxides with fluorite-structured layers between CuO2 planes

    International Nuclear Information System (INIS)

    The three first members of the Cr-12s2 (s = 1, 2, 3) homologous series, i.e. CrSr2YCu2O8 (Cr-1212), CrSr2(Y1.5Ce0.5)Cu2O10 (Cr-1222) and CrSr2(Y1Ce2)Cu2O12(Cr-1232) are synthesized by high pressure high temperature (HPHT) 6 GPa and 1550 deg. C process. Though the Cr-1212 and Cr-1232 could not be formed in single phase with full Cr, the Cr-1222 is achieved in pure phase with space group I4/mmm. These compounds belong to the multi-layered copper oxides series that differ from each other only in terms of the (Ce,Y)-[O2-(Ce,Y)]s-1 layer blocks between two identical CuO2 planes with s = 1, 2 and 3. At 5 K, the magnetization M(H) experiments showed some ferromagnetic like hysteresis loops though the characteristic Mr and Hc were not seen clearly. None of the studied compounds exhibited superconductivity down to 5 K

  14. Structure, strength, and electric conductivity of a Cu-Cr copper-based alloy subjected to severe plastic deformation

    Science.gov (United States)

    Islamgaliev, R. K.; Nesterov, K. M.; Valiev, R. Z.

    2015-02-01

    The effect of severe plastic deformation on the structure, strength, and electric conductivity of a Cu-Cr copper-based alloy has been studied. In ultrafine-grained specimens produced by severe plastic deformation by torsion and equal-channel angular pressing, the average grain size has been determined and particles of precipitates have been identified. The dependences of the strength and electric conductivity on conditions of severe plastic deformation and subsequent heat treatment have been assessed. The effect of dynamic aging in the Cu-Cr alloy has been found that leads to an increase in both the strength and the electric conductivity. It has been found that the ultrafine-grained alloy can demonstrate a combination of a high ultimate strength (790-845 MPa) and an increased electric conductivity (81-85% IACS).

  15. 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

    Several soil remediation techniques for As, Cu and Cr contaminated soil utilize adsorption of contaminants to ferrihydrite as the removal mechanism, even though ferrihydrite will transform to secondary iron oxides and part of the sorption capacity will be lost. Transformation of ferrihydrite...... 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...... the fate of ferrihydrite and associated contaminants during burial enabling an improvement of the methods for amending contaminated soil with Fe-WTR. (C) 2014 Elsevier Ltd. All rights reserved....

  16. Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

    International Nuclear Information System (INIS)

    Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalysts with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a test reaction. It was found that along to both basic components, the system under study also contained the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate was catalytically active. During the first period of the reaction the equilibrium was being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties change rather significantly after thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably connected with the changes in the valence state of the catalytically active components of the catalyst. (author). 5 figs., 4 tabs., 16 refs

  17. Microstructural development and evolution of liquid phase sintered Cr-Cu composites

    Directory of Open Access Journals (Sweden)

    Khomenko E.

    2007-01-01

    Full Text Available Features of the microstructure formation of Cr-Cu composites under impregnation followed by liquid phase sintering of reduced and electrolytic chromium powders at 1200°C in a vacuum of (2-4×10-3Pa have been studied. The refractory component particle size distribution in the microstructure of samples with reduced chromium sintered for 60 min is shown to obey a normal logarithmic law; with distribution parameters being sensitive to the volume fraction of the refractory particles. The calculated values of the dihedral angle are close to the value of one of the modes in the experimental dihedral angle distribution for the microstructure of electrolytic chromium based samples (115°. The interfacial and interparticle surface energies ratio σsl/σss>0.5 is shown to correspond to theory for the Crs-Cul system in equilibrium, which indicates the presence of skeleton structure elements in the course of composition formation under liquid phase sintering (including the case of excess liquid phase. Experimentally determined interparticle and interfacial surface areas, solid particle contiguity and continuity are discussed in terms of concurrent diffusion-controlled particle coarsening (in Lifshitz, Slyozov and Wagner theory and particle coalescence (in German’s model. The kinetics of shrinkage for the composites with 50...55 % solid-phase volume-fractions at heating and isothermal sintering in a vacuum at a temperature of 1200°C in terms of linearly viscous rheological theory are discussed.

  18. Structural and physical properties of the nano-crystalline Al-substituted Cr-Cu ferrite

    Science.gov (United States)

    Amer, M. A.; Meaz, T. M.; Mostafa, A. G.; El-Ghazally, H. F.

    2013-10-01

    Ferrite nanoparticles are promising future materials for applications in medicine, ferrofluids, technical designing and other fields. The as-prepared CuAlxCr0.8-xFe1.2O4 nanoparticles (0≤x≤0.8) have been prepared by the chemical co-precipitation method. A study of the structure and other physical properties of the samples was carried out by using X-ray, infrared, Mössbauer and vibrating sample magnetometer (VSM) patterns and particle size distributions. The results revealed the ultrafine nature of the particles, where the crystallite size and the average particle size have been deduced. The values of the lattice parameters and crystallite size were dependent on the substitution factor x, while the oxygen parameter was higher than the standard value and independent on x. In addition to six absorption bands, a triple band attributed to the retained water in the samples was observed in the infrared spectra. The absorption bands indicated the existence of Fe2+ ions in the sample sublattices. The Mössbauer and VSM patterns proved the presence of small magnetic field in the samples, where the saturation magnetization, coercivity, hyperfine interaction parameters, cation distributions and magnetization were dependent on x.

  19. 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

  20. Macromolecule oxidation and DNA repair in mussel (Mytilus edulis L.) gill following exposure to Cd and Cr(VI)

    International Nuclear Information System (INIS)

    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

  1. Macromolecule oxidation and DNA repair in mussel (Mytilus edulis L.) gill following exposure to Cd and Cr(VI)

    Energy Technology Data Exchange (ETDEWEB)

    Emmanouil, C. [School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Sheehan, T.M.T. [Regional Toxicology Laboratory, City Hospital, Dudley Road, Birmingham B18 7QH (United Kingdom); Chipman, J.K. [School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)]. E-mail: J.K.Chipman@bham.ac.uk

    2007-04-20

    The oxidation of DNA and lipid was analysed in the marine mussel (Mytilus edulis) in response to exposure (10 {mu}g/l and 200 {mu}g/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 {mu}g 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 {mu}g/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.

  2. Simultaneous cloud point extraction of low levels of Cd, Cr and Hg in seaweed species prior to neutron activation analysis

    International Nuclear Information System (INIS)

    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. The pH concentration of PAN and TAN, concentration of PONPE-20, ionic strength and temperature affecting the separation were optimized. The recoveries of each of the elements under the optimum conditions of pH 8.6, (PAN/TAN) = 1 X 10-4 M, (PONPE-20) = 0.1 % (m/v), ionic strength = 0.05 M KNO3, and temperature of 41 0C were > 98%. The concentrations of the elements were determined by neutron activation analysis using the Dalhousie University Slowpoke-2 reactor (DUSR) facility. The detection limits of Cd, Cr and Hg were 6.0, 3.6 and 1.2 ng g-1 respectively, and precision and accuracy of measurements were evaluated. The method was successfully applied to the simultaneous determination of Cd, Cr and Hg in fifteen Ghanaian seaweed species. (au)

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

    Science.gov (United States)

    Chaúque, Eutilério F. C.; Dlamini, Langelihle N.; Adelodun, Adedeji A.; Greyling, Corinne J.; Catherine Ngila, J.

    2016-04-01

    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-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. Raman spectrum of Cu2CdSnSe4 stannite structure semiconductor compound

    Science.gov (United States)

    Rincón, C.; Quintero, M.; Moreno, E.; Power, Ch.; Quintero, E.; Henao, J. A.; Macías, M. A.

    2015-12-01

    Raman spectrum of Cu2CdSnSe4 quaternary semiconductor compounds with tetragonal stannite-type structure (space group I 4 bar 2m), a material which has been recognized recently as a potential candidate for thermoelectric applications, has been studied. Most of the fourteen Raman lines expected for this compound according to group theory analysis were observed in the spectrum. Besides to the two strongest A1-symmetry stannite modes at 172 and 192 cm-1 originated from the motion of Se anion around the Cu and Sn cations which remain at rest, the leftover observed Raman lines were tentatively assigned to specific eigenmodes of the stannite crystal structure by comparing these line frequencies with those obtained for this compound from IR measurements as well as with those calculated Raman modes for the Cu2ZnSnSe4 stannite-compound reported in the literature. Two spurious Raman lines related to the presence in this compound of SnSe and SnSe2 minority secondary phases have also been found in the Raman spectrum.

  5. 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

    2016-03-01

    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. PMID:26546702

  6. Simultaneous extraction of Cr(VI) and Cu(II) from humic acid with new synthesized EDTA derivatives.

    Science.gov (United States)

    Zhang, Tao; Wu, Ying-Xin; Huang, Xiong-Fei; Liu, Jun-Min; Xia, Bing; Zhang, Wei-Hua; Qiu, Rong-Liang

    2012-07-01

    Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid and its salts (EDTA) is very effective at removing cationic metals and has been utilized globally. However it is ineffective for anionic metal contaminants or metals bound to soil organic matter. The simultaneous removal of cationic and anionic metal contaminants by soil washing is difficult due to differences in their properties. The present study evaluated the potential of a washing process using two synthesized EDTA-derivatives, C(6)HEDTA (2,2'-((2-((carboxymethyl)(2-(hexanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid) and C(12)HEDTA (2,2'-((2-((carboxymethyl) (2-(dodecanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid), which consist of a hydrophilic polycarboxylic moiety and a hydrophobic moiety with a monoalkyl ester group. A series of equilibrium batch experiments at room temperature were conducted to investigate the efficacy of C(6)HEDTA and C(12)HEDTA as extractants for both oxyanion Cr(VI) and cationic Cu(II). Results showed that either C(6)HEDTA or C(12)HEDTA can extract both Cr(VI) and Cu(II) from humic acid simultaneously. However, C(6)HEDTA was less effective for Cr(VI) probably because it has no surface activities to increase solubility of humic acid, like C(12)HEDTA. Extraction of Cr(VI) was mainly attributed to the decreased surface tension and enhanced solubility of organic matter. Extraction of Cu(II) was attributed to both the Cu(II) chelation and enhanced solubility of humic acid. It was demonstrated that the hydrophilic polycarboxylic moiety of C(12)HEDTA chelates cations while the monoalkyl ester group produces surface active properties that enhance the solubility of humic acid. PMID:22555067

  7. The Mechanism of Thermomechanical Training of a Newly Developed Fe-Mn-Si-Cr-Cu Shape Memory Alloy

    OpenAIRE

    Dunne, D.; Li, H.

    1995-01-01

    Thermomechanical training was carried out on a newly developed Fe-20Mn-6Si-7Cr-1Cu shape memory alloy. It was observed that the effectiveness of thermomechanical training largely depends on the recovery annealing temperature and the pre-strain during training. Based on the analysis of the changes in critical stress for martensite formation, the critical stress for slip deformation, the phase transformation temperatures and microstructural development during training, it was concluded that the...

  8. The dependence of superconducting signal on the synthesis protocol of (Hg, Cr)Sr2CuO4+δ

    International Nuclear Information System (INIS)

    The dependence of synthesis procedures followed for making 1201 type (Hg, Cr)Sr2CuO4+δ samples, on their superconducting properties have been evaluated by ac-susceptibility and dc-magnetization measurements. It was found that a green sample in gold tube, shows remarkably improved diamagnetic signal and inter-grain coupling than bare sample placed in the quartz tube, during synthesis. (author)

  9. Spatial distribution of heavy metals (Cu, Pb, Zn, and Cd) in sediments of a coastal wetlands in eastern Fujian, China

    Institute of Scientific and Technical Information of China (English)

    Lili Zhao; Yong Tan; Dongjin He; Weibin You; Haiqing Hu; Wei Hong; Xiaojuan LIAO; Shihong Xiao; Ren Wang; Jinbiao Cai; Xuncheng Fan

    2015-01-01

    We investigated the spatial distribution (horizontal and vertical concentrations) of copper (Cu), lead (Pb), zinc (Zn), and cadmium (Cd) in five wetland types (mudflat, aquaculture wetland, water area, farmland wetland and mangrove) from three areas (Ningde, Fuding, and Xiapu), China. Cu concentrations in five wetland types descended in the order:farm wetland, mudflat, aquaculture, water area and mangrove. Pb concentrations decreased in the order: aquaculture, mangrove, farm wetland, mudflat, and water area. Zn content decreased in the order: farm wetland, water area, aquaculture, mudflat and mangrove, and Cd content decreased as follows: mangrove, aquacul-ture, water area, mudflat, and farm wetland. Comparison of the concentrations of the same heavy metals in different areas showed that the highest Cu (63.75 mg kg-1) and Zn (152.32 mg kg-1) concentrations occurred in Ningde coastal wetlands; Pb (110.58 mg kg-1) and Cd (2.81 mg kg-1) contents were highest in Fuding wetlands, and the average contents of all heavy metals were very low in Xiapu wetlands. Examination of the vertical distribution showed that the Cu content was high in all mudflat layers;Pb and Cd concentrations were highest in aquaculture and mangrove wetlands, respectively, and Zn content was highest in farm wetlands. The spatial distribution of Cu and Zn contents for different areas decreased as follows:Ningde [ Fuding [ Xiapu, for Pb and Cd were most concentrated in Fuding coastal wetlands. Concentrations of Zn and Cu were highly correlated, while Zn and Cu were not significantly correlated with Pb.

  10. Sensitization of CdS nanoparticles onto reduced graphene oxide (RGO) fabricated by chemical bath deposition method for effective removal of Cr(VI)

    Energy Technology Data Exchange (ETDEWEB)

    Pawar, Rajendra C.; Lee, Caroline Sunyong, E-mail: sunyong523@gmail.com

    2013-09-16

    RGO (Reduced Graphene Oxide)–CdS composites were successfully synthesized by chemical bath deposition (CBD) method onto soda lime glass substrate at low temperature (70 °C). Their structural, optical and morphological properties were studied using X-ray diffraction, UV–Vis spectrophotometer, Raman spectroscopy, Brunauer–Emmett–Teller, Field emission scanning electron microscope and transmission electron microscope. It is clearly seen that spherically shaped CdS nanoparticles with an average diameter 30 nm are uniformly coated over the entire graphene sheet. Further, synthesized CdS nanoparticles and RGO–CdS nanocomposites were investigated for the reduction of Cr(VI) under visible light. The photocatalytic results show that photodegradation rate of RGO–CdS composites is two times higher than that of CdS nanoparticles toward reduction of Cr(VI). The improved photocatalytic performance by combining RGO with CdS nanoparticles, is attributed to its increased specific surface area (47.44 m{sup 2} g{sup −1}), efficient transportation of photoelectrons and improved absorbance of CdS nanoparticles. Therefore, it was found that RGO in RGO–CdS composites makes a significant impact on photocatalytic activity toward reduction of Cr(VI), making an excellent candidate for water refiner. - Graphical abstract: Display Omitted - Highlights: • Chemical bath deposition was used to deposit CdS nanoparticles over graphene sheets. • RGO/CdS shows effective photocatalytic reduction of Cr(VI) under visible light. • High photocurrent of RGO/CdS proved reduction in recombination due to graphene. • High specific surface area (47.44 m{sup 2} g{sup −1}) of RGO/CdS improves Cr(VI) adsorption.

  11. Direct determination of Cr and Cu in urine samples by electrothermal atomic absorption spectrometry using ruthenium as permanent modifier (R1)

    Energy Technology Data Exchange (ETDEWEB)

    Lelis, Katia Linces Alves; Rocha, Clelia Aparecida [Instituto de Patologia Clinica Hermes Pardini, 30140-070 Belo Horizonte, MG (Brazil); Magalhaes, Cristina Goncalves; Silva, Jose Bento Borba of [Departamento de Quimica, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG (Brazil)

    2002-12-01

    In this study Ru, deposited thermally on an integrated platform pyrolytic graphite tube, is proposed as a permanent modifier for the determination of Cu and Cr in urine samples by electrothermal atomic absorption spectrometry. The samples were diluted 1:1 with nitric acid (1% v/v). Pyrolysis and atomization temperatures for spiked urine samples were 1,100 C and 1,900 C respectively for Cu, and 1,400 C and 2,500 C respectively for Cr. For comparison purposes, the conventional modification with Pd+Mg was also studied. The sensitivity for Ru as permanent modifier was higher for the two analytes. The characteristic masses were 7.3 and 17.7 for Cr and Cu. The detection limits (3{sigma}) were 0.22 and 0.32 {mu}g/L, for Cr and Cu, respectively. Good agreement was obtained with certified urine samples for the two elements. (orig.)

  12. Investigation on the preparation and mechanical properties of porous Cu35Ni15Cr alloy for a molten carbonate fuel cell

    Directory of Open Access Journals (Sweden)

    Li Cong

    2015-12-01

    Full Text Available The preparation process of porous Cu35Ni15Cr alloy was studied in this paper. The effect of ball milling time and sintering temperature on the porosity of Cu35Ni15Cr alloy was identified. It was found that 18 h ball milling and 950 °C sintering are the most promising parameters for the preparation of porous Cu35Ni15Cr alloy. The products have a ~62 % porosity. The alloy consists of an α phase and β phase. The influence of deformation temperature and loading rate on the mechanical properties of Cu35Ni15Cr alloys was investigated. The results show that with decreasing deformation temperature, the yield strength and elastic modulus of the porous alloy increase. With the increase of loading rate, the yield strength of these alloys shows an increasing trend, but the elastic modulus is on a steady level.

  13. Characterization and Activity of Cr,Cu and Ga Modified ZSM-5 for Direct Conversion of Methane to Liquid Hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    Nor Aishah Saidina Amin; Didi Dwi Anggoro

    2003-01-01

    Direct conversion of methane using a metal-loaded ZSM-5 zeolite prepared via acidic ion exchange was investigated to elucidate the roles of metal and acidity in the formation of liquid hydrocarbons. ZSM-5 (SiO2/Al2O3=30) was loaded with different metals (Cr, Cu and Ga) according to the acidic ion-exchange method to produce metal-loaded ZSM-5 zeolite catalysts. XRD, NMR, FT-IR and N2 adsorption analyses indicated that Cr and Ga species managed to occupy the aluminum positions in the ZSM-5 framework. In addition, Cr species were deposited in the pores of the structure. However, Cu oxides were deposited on the surface and in the mesopores of the ZSM-5 zeolite. An acidity study using TPD-NH3, FT-IR, and IR-pyridine analyses revealed that the total number of acid sites and the strengths of the Bronsted and Lewis acid sites were significantly different after the acidic ion exchange treatment.Cu loaded HZSM-5 is a potential catalyst for direct conversion of methane to liquid hydrocarbons. The successful production of gasoline via the direct conversion of methane depends on the amount of aluminum in the zeolite framework and the strength of the Bronsted acid sites.

  14. Heat Transfer Analysis of Two Kinds of Mechanically Jointed GBST1308/CuCrZr Plasma Facing Components of EAST

    Institute of Scientific and Technical Information of China (English)

    CHONG Fali; CHEN Junling; LI Jiangang; ZHENG Xuebin; EAST team

    2008-01-01

    Doped graphite GBST1308,mechanically jointed to CuCrZr alloys,will be applied on EAST superconducting as plasma facing material (PFM).Two joint structures called joint-1 and joint-2 were evaluated by means of thermal response tests using electron beam facility.The experimental results showed that the temperature differences of two joints were not significant,and the maximum surface temperature was about 1055℃ at a load of 4 MW/m2,which had a good agreement with the simulated results by ANSYS code.The results indicated that the doped graphite GBST1308/CuCrZr mock-up can withstand heat flux deposition of 4 MW/m2 except at the screw-fastened region,and joint-2 could be more suitable to higher heat flux region such as divertor target.But under the higher heat flux,both joints are unacceptable,an advanced PFM and its integration with the heat sink have to be developed,for example,vacuum plasma spraying tungsten coatings on the CuCrZr might be a good choice.

  15. Experimental Verification of the Theoretical Prediction of the Phase Structure of a Ni-Al-Ti-Cr-Cu Alloy

    Science.gov (United States)

    Wilson, A.; Bozzolo, G.; Noebe, R. D.; Howe, J. M.

    2002-01-01

    The Bozzolo-Ferrante-Smith (BFS) method for alloys was applied to the study of NiAl-based materials to assess the effect of alloying additions on structure. Ternary, quaternary and even pentalloys based on NiAl with additions of Ti, Cr and Cu were studied and experimental verification of the theoretical predictions including the phase structure of a Ni-Al-Ti-Cr-Cu alloy is presented. Two approaches were used, Monte Carlo simulations to determine low energy structures, and analytical calculations of the energy of high symmetry configurations which give physical insight into preferred structures. The energetics for site occupancy in ternary and quaternary systems were calculated leading to an indirect determination of solubility limits at 0 K. Precipitate formation with information concerning structure and lattice parameter were also 'observed' computationally and the general characteristics of a Ni-Al-Ti-Cr-Cu alloy were correctly predicted. The results indicate that the BFS method for alloys can be a useful tool for alloy design and can be used to complement experimental alloy design programs.

  16. Decontamination of Cr(VI), Cu(II) and phenol in some tannery effluents by gamma rays

    International Nuclear Information System (INIS)

    Industrialization has led to a number of environmental problems, such as release of toxic metals and other toxic organic and inorganic compounds to the environment. Among all, the rapid expansion of leather related industries in Pakistan have resulted in considerable environmental problems and effluents from processing of both domestic and imported hides and skins have increased pollution to alarming levels. Some tannery effluents of Peshawar area investigated in the present study showed high load of COD (537-1068 mg/L), Cr(VI) (2.7-12.6 mg/L), Cu(II) (2.6-11.4 mg/L) and phenol (0.1-4.2 mg/L). These contaminants are very toxic and must be removed from effluents before releasing into water bodies. A novel technique of gamma irradiation has been investigated to decrease the load of COD and concentrations of Cr(VI), Cu(II) and phenol associated with tannery effluents to the permitted values. It was observed that COD in the effluents can be brought to the permitted level by applying radiation dose of 3 kGy and the same dose was also sufficient to remove more than 96% of Cr(VI). A radiation dose of 2.5 kGy was required to remove more than 95 % of Cu(II) and 100 % degradation of phenol in tannery effluents could be achieved by only one kGy of radiation dose. (authors)

  17. Determination of accuracy level elements of Co, Ni, Cr, Cu in SRM using the multi element method by AAS

    International Nuclear Information System (INIS)

    In nature, all elements are associated with the other element forming minerals in rocks. Minerals are formed by element with similar characteristics and inclined existence together. The element analysis of the rock samples there is matrix element (the other domineer element with similar characteristics) it can influent the result analysis so that cause deviation. The multi element method is the standard in surpassing deviation caused by matrix element influences. The multi element method is the one of standard method which used in Sub Division of Geochemical Exploration, that never be done any test the result analysis before. The research aim to test the accuracy level of the result analysis for multi element method for Co, Ni, Cr, Cu elements in six samples of SRM with AAS. The result analysis of multi element method by Atomic Absorption Spectroscopy, got the level accuracy about Co 89,98%-92,93%, Ni 90,13%-92,82%, Cr 89,71-95,38%, Cu 90,09%-92,82% with average deviation is <10%. Testing results of the analysis with student t Co element, Ni, Cr there is no significant difference / identical to SRM with 95% confidence level and Cu there are significant differences with the SRM 99% confidence level, the low deviations prove that the materials, equipment, and human resources, in a good condition fit for use in element analysis. (author)

  18. 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.

  19. Effects of Acute and Chronic Heavy Metal (Cu, Cd, and Zn) Exposure on Sea Cucumbers (Apostichopus japonicus)

    OpenAIRE

    Li, Li; Tian, Xiangli; Yu, Xiao; Dong, Shuanglin

    2016-01-01

    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...

  20. 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.

  1. 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

  2. Photosensitivity of ZnO/CdS/Cu(In,Ga)Se2 heterophotoelements at γ-irradiation

    International Nuclear Information System (INIS)

    The effect of γ-irradiation on the photosensitivity of thin-film ZnO/CdS/Cu(In,Ga)Se2 heterophotoelements in native and linearly polarized light is investigated. It is shown that γ-irradiation at T= 300 K practically is not influence on photoelectrical parameters of these heterojunctions up to radiation doses ∼ 1.1x1018 quanta/cm2. It is concluded that application of ZnO/CdS/Cu(In,Ga)Se2 heterophotoelements at conditions of high radiation loading is possible

  3. Nerita chameleon as Biomonitoring Agent for Pb, Cd, Cu and Zn in Malaysian Intertidal Rocky Shore Environment

    Directory of Open Access Journals (Sweden)

    Mohd Fuad Miskon

    2015-06-01

    Full Text Available Pb, Cd, Cu and Zn in the soft tissue of Nerita chameleon from particular rocky shore sites along the east coast of Peninsular Malaysia were investigated. Samples were measured using ICP-MS with standard configuration. The metal accumulation patterns indicate consistent enrichment of essential metals. Locations with relatively high concentrations of the contaminant metals Pb, Cd and Cu are related to their close proximity to industrial activities and urban sites. Comparison with maximum permissible limits of toxic metals in food indicated the values were well within safety levels.

  4. One-Dimensional Reaction-Diffusion Simulation of Cu Migration in Polycrystalline CdTe Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Da [Arizona State University; Akis, Richard [Arizona State University; Brinkman, Daniel [Arizona State University; Sankin, Igor [First Solar; Fang, Tian [First Solar; Vasileska, Dragica [Arizona State University; Ringhofer, Christain [Arizona State University

    2014-06-13

    In this work, we report on developing 1D reaction-diffusion solver to understand the kinetics of p-type doping formation in CdTe absorbers and to shine some light on underlying causes of metastabilities observed in CdTe PV devices. Evolution of intrinsic and Cu-related defects in CdTe solar cell has been studied in time-space domain self-consistently with free carrier transport and Poisson equation. Resulting device performance was simulated as a function of Cu diffusion anneal time showing pronounced effect the evolution of associated acceptor and donor states can cause on device characteristics. Although 1D simulation has intrinsic limitations when applied to poly-crystalline films, the results suggest strong potential of the approach in better understanding of the performance and metastabilities of CdTe photovoltaic device.

  5. Effects of liming an acid soil amended with sewage sludge enriched with Cd, Cu, Ni, and Zn on yield and Cd content of wheat grain

    Energy Technology Data Exchange (ETDEWEB)

    Bingham, F.T. (Univ. of California, Riverside); Page, A.L.; Mitchell, G.A.; Strong, J.E.

    1979-04-01

    An acid soil (pH 5.2) was treated +- lime and 1% sewage sludge enriched with three concentrations each of Cd, Zn, Cu, and Ni in a 3/sup 4/ complete factorial design experiment (81 treatments +- lime). These treated soils were placed in pots and cropped with wheat (Triticum aestivum L.). Analysis of variance revealed significant main effects on grain yield from all metal additions to the acid soil and from Cd and Cu only in the limed soil. Significant main effects on the concentration of Cd in grain occurred with all metals added in the limed soil, but only from Cd, Zn, and Ni on the acid soil. Significant multiple metal interactions occurred in all cases. Multiple regression equations were developed for estimating grain yield and Cd content from soil metal additions and saturation extract metal content. Grain Cd concentrations were highly correlated with soil metal additions (R/sup 2/ = 0.978 and 0.988 for limed and unlimed soils, respectively) and saturation extract metals (R/sup 2/ = 0.879 and 0.950 for limed and unlimed soils). The best fit equations were used to calculate metal equivalent values for soil metals added (SME) which were then used to develop regression equations and graphs relating grain yield to SME.

  6. Development of HIP technique for bonding of CuCrZr with stainless steel and beryllium for application to the ITER first wall

    International Nuclear Information System (INIS)

    Bonding techniques have been developed for the fabrication of the ITER first wall (FW). The ITER FW consists of beryllium armor tiles, a copper alloy heat sink, stainless steel (SS) cooling pipes and a backing plate that are integrated by metallurgical bonding. Hot Isostatic Pressing (HIP) has been selected as the reference bonding method in the ITER design. With respect to the copper alloy material to be used as the heat sink, a precipitation hardened copper alloy (CuCrZr) has been chosen as an alternative to an alumna dispersion strengthened copper (DSCu) with possible advantages of reduced fabrication cost and higher fracture toughness. The objective of this study is to develop the fabrication technique for the application of CuCrZr heat sink material, which should be consistent with the overall fabrication procedure of the FW. CuCrZr needs heat treatment of annealing and ageing to maintain its high mechanical strength. Required conditions for the heat treatments are also investigated here. This report consists of three parts: 1) screening of CuCrZr/SS HIP heat treatment and post HIP heat treatment conditions; 2) screening of the Be/CuCrZr HIP conditions with selection of an appropriate interlayer, and 3) trial fabrication and high heat flux testing of CuCrZr/SS FW partial mockup. The screening tests showed that the fracture toughness of ∼276kJ/m2 obtained for the CuCrZr/SS joints was higher than that of DSCu/SS joints. It was possible to apply lower HIP temperature for Be/CuCrZr bonding than for Be/DSCu, which is beneficial to maintain the mechanical strength of CuCrZr. Metallurgical observation showed that a grain of CuCrZr was somewhat coarsened, but there was no defects observed at the HIP-bonded interface. By applying the HIP and heat treatment conditions selected by the screening tests, a partial mockup of CuCrZr/SS FW was successfully fabricated. The mock-up showed good heat removal and thermo-mechanical performances in the high heat flux testing under

  7. First-principles study on the magnetism and electronic structure in 3d transition metal (X=Sc, V, Cr, Mn, Fe, Ni, Cu) doped CoO

    Science.gov (United States)

    Liu, R. X.; Wang, X. C.; Chen, G. F.; Yang, B. H.

    2016-03-01

    We have studied the electronic structure and magnetism of the single transitional metal element X=Sc, V, Cr, Mn, Fe, Ni, Cu-doped CoO systems by first-principles calculations. At X=Sc, Cr, Cu, the binding energy of the doped systems is lower than pure CoO, suggesting that these systems are energetically stable. In the Sc, V, Cr, Mn, Fe, Ni, Cu-doped 2×2×2 CoO supercells, the total magnetic moments are 3.03, 5.64, 6.80, 7.70, 6.93, 2.30 and 1.96 μB, respectively. At X=Cr and Fe, the doped CoO systems are half-metallic with a high spin polarization. The large magnetic moment and high spin polarization in the Cr and Fe-doped CoO are important for the design of the spintronic devices.

  8. (Ca/Sr)Au xCd 1- x: Stacking variants of the CrB-FeB series

    Science.gov (United States)

    Harms, Wiebke; Dürr, Ines; Daub, Michael; Röhr, Caroline

    2010-01-01

    The structural chemistry of binary 1:1 alkaline earth metallides AIIM ( M=p-block or late transition element) is dominated by planar M zig-zag chains, which are stacked in different orientations (CrB ( c) to FeB ( h) type) and with variable stacking distances (types I and II). As a case study of the electronic influences, the substitution of Au against Cd in the respective Ca and Sr aurides was examined by means of experimental, crystallographic and computational methods. Starting from CaAu, up to 11% of Au can be substituted by Cd without a change in the CrB structure type (orthorhombic, space group Cmcm, a=398.2(1), b=1122.6(6), c=460.9(2) pm, Z=4, R1=0.0303). Starting from SrAu (stacking sequence (hc)2(h2c)2), depending on the proportion of the Cd substitution a successive change to structures with increased hexagonality is observed: In SrAu0.93Cd0.07 (monoclinic, space group P21/m, a=621.3(4), b=472.4(2), c=1216.1(9) pm, β=96.97(5)∘, Z=6, R1=0.0467) the stacking sequence is h2 c, i.e. the hexagonality is 66.67%. A slightly more increased Cd content in SrAu0.78Cd0.22 (orthorhombic, space group Pnma, a=3243.3(8), b=474.17(8), c=626.20(9) pm, Z=16, R1=0.0682) drives the hexagonality to 75%, with a (h3c)2 stacking sequence known from several rare earth nickel compounds. Further Cd substitution is not possible. However, in the Cd-rich section of the two series, where the CsCl/β-brass structure type occurs for both alkaline earth elements, a small Au substitution, as determined from powder data by Rietveld refinements, is possible. The substitution limit and the stability ranges of the CsCl and the CrB type can be rationalized from the calculated band structures. Geometrical and electronic criteria are used to compare and discuss the stability ranges in a structural map.

  9. One Single Molecule as a Multifunctional Fluorescent Probe for Ratiometric Sensing of Fe3+, Cr3+ and Colorimetric Sensing of Cu2+

    Directory of Open Access Journals (Sweden)

    Yanqiu Yang

    2014-12-01

    Full Text Available The reagent Rh-C, incorporating a rhodamine moiety and a coumarin backbone and prepared via click chemistry, was developed as the first single molecule for detecting Cu2+, Fe3+ and Cr3+. Its response to Cu2+ in different solutions is visible to the naked eye and it exhibits a ratiometric fluorescence response to Fe3+ in methanol and Cr3+ in acetonitrile.

  10. 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.

  11. 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.

  12. Support effect on the structure and CO oxidation activity of Cu-Cr mixed oxides over Al2O3 and SiO2

    International Nuclear Information System (INIS)

    Cu-Cr based catalysts supported on silica and alumina with 5 wt% total loading of (CuO + Cr2O3), in different molar ratios, were prepared by wet impregnation. The samples were studied by nitrogen adsorption isotherms (BET), temperature-programmed reduction (TPR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Their catalytic activity was tested in the CO oxidation reaction. Different structures were obtained in dependence of the support, the atomic ratio and the calcination temperature. In particular, whereas on Al2O3 there was no experimental evidence for interaction between Cu and Cr, over the silica supported systems formation of new phases CuCr2O4 and CuCrO2 occurred. Moreover, due to the different metal support interaction the increasing calcination temperature affected differently the surface segregation process of the two oxides. Indeed, at variance with the alumina case, Cu and Cr were found to segregate at the surface of the silica systems. The catalytic tests in CO oxidation indicated a synergetic effect between copper and chromium in the mixed oxides supported on silica and calcined at 500 deg. C. An increased calcination temperature affected negatively the activity due to surface sintering and formation of less active phases

  13. Effects of annealing atmosphere on structure, optical and magnetic properties of Zn0.95Cu0.02Cr0.03O diluted magnetic semiconductors

    International Nuclear Information System (INIS)

    Zn0.95Cu0.02Cr0.03O nanoparticles were successfully prepared by sol–gel method under different atmospheres (air and argon). X-ray diffraction, transmission electron microscope, X-ray photoelectron spectroscopy, photoluminescence spectroscopy and vibrating sample magnetometer were used to investigate the effect of annealing atmospheres on the structure, optical and magnetic properties of Zn0.95Cu0.02Cr0.03O diluted magnetic semiconductors. The results showed that the Zn0.95Cu0.02Cr0.03O nanoparticles with 16.5 nm and 17.2 nm sintered in different atmospheres had a hexagonal wurtzite structure without any secondary phases. X-ray photoelectron spectroscopy analysis indicated that the Cr ions were the +3 and the Cu exhibits different valence state in the Zn0.95Cu0.02Cr0.03O samples annealed in different atmosphere. The annealing atmosphere was found to have effect on the optical and magnetic properties of the Zn0.95Cu0.02Cr0.03O samples

  14. Phase Stability and Electronic Structure of In-Free Photovoltaic Materials Cu2IISnSe4 (II: Zn, Cd, Hg)

    Science.gov (United States)

    Nakamura, Satoshi; Maeda, Tsuyoshi; Wada, Takahiro

    2011-05-01

    We have theoretically evaluated the phase stability and electronic structure of Cu2CdSnSe4 and Cu2HgSnSe4 and compared the results with those of Cu2ZnSnSe4. The enthalpies of formation for kesterite (KS), stannite (ST), and wurtz-stannite (WST) phases of Cu2ZnSnSe4 (CZTSe), Cu2CdSnSe4, and Cu2HgSnSe4 were calculated by first-principles calculations. In Cu2CdSnSe4 and Cu2HgSnSe4, the stannite (ST) phase is the most stable among these phases. The valence band maximum (VBM) of ST-type Cu2CdSnSe4 consists of antibonding orbitals of Cu 3d and Se 4p, while the conduction band minimum (CBM) consists of antibonding orbitals of Sn 5s and Se 4p. The VBM of Cu2HgSnSe4 also consist of antibonding orbitals of Cu 3d and Se 4p. However, the CBM of Cu2HgSnSe4 consists of antibonding orbitals of Hg 6s, Sn 5s, and Se 4p.

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

    International Nuclear Information System (INIS)

    X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu2Cd1-zMn zGeSe4 and Cu2Cd1-zFe zGeSe4 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 Cu2Cd1-zFe zGeSe4 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 Cu2Cd1-zMn zGeSe4 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

  16. Valorization of biosorbent obtained from a forestry waste: Competitive adsorption, desorption and transport of Cd, Cu, Ni, Pb and Zn.

    Science.gov (United States)

    Cutillas-Barreiro, Laura; Paradelo, Remigio; Igrexas-Soto, Alba; Núñez-Delgado, Avelino; Fernández-Sanjurjo, María José; Álvarez-Rodriguez, Esperanza; Garrote, Gil; Nóvoa-Muñoz, Juan Carlos; Arias-Estévez, Manuel

    2016-09-01

    Bark from Pinus pinaster is one of the most abundant forestry wastes in Europe, and among the proposed technologies for its reutilization, the removal of heavy metals from wastewater has been gaining increasing attention. In this work, we have studied the performance of pine bark for heavy metal biosorption on competitive systems. Pb, Cu, Ni, Zn and Cd sorption and desorption at equilibrium were studied in batch experiments, whereas transport was studied in column experiments. Batch experiments were performed adding simultaneously different concentrations (0.08-3.15mM) of two or more metals in solution to pine bark samples. Column experiments were performed with 10mM solutions of two metals or a 5mM solution of the five metals. In general, the results under competitive conditions were different to those obtained in monoelemental experiments. The multi-metal batch experiments showed the adsorption sequence Pb≈Cu>Cd>Zn>Ni for lower metal doses, Pb>Cu>Cd>Zn>Ni for intermediate doses, and Pb>Cu>Cd≈Zn≈Ni for high metal doses. Desorption followed the sequence Pbretention, with high capacity to displace Cd, Ni and Zn from adsorption sites on pine bark. The transport experiments produced comparable results to those obtained in the batch experiments, with pine bark retention capacity following the sequence Pb>Cu>Zn>Cd>Ni. The presence of a second metal affected the transport of all the elements studied except Pb, and confirmed the strong influence of Pb and Cu on the retention of the other metals. These results can help to appropriately design decontamination systems using this forestry waste. PMID:27232204

  17. CONCENTRATIONS OF Cd, Cu AND Zn IN SEDIMENTS COLLECTED FROM URBAN LAKES AT KELANA JAYA, PENINSULAR MALAYSIA

    Institute of Scientific and Technical Information of China (English)

    Ahmad Ismail; Chee Kong YAP; Fong Fei Chan

    2004-01-01

    Kelana Jaya Municipal Park is a popular recreation park in Petaling Jaya. The five lakes, located within the Park, were ex-mining ponds, functioning as flood retention ponds and receiving effluents from nearby human activities mainly from residents and transportation. A study was conducted to determine the distribution and sources of heavy metals (Cd, Cu and Zn) in the sediments of Kelana Jaya Lakes. Concentrations of Cd, Cu, and Zn for surface sediment were determined by using aqua-regia method and sequential extraction technique. Total Cd concentrations ranged from 0.48 μg/g to 2.68 μg/g dry weight (dw) for all lakes. Total Cd concentrations in sediment of all lakes exceeded CCME (Canadian Council of Ministers of the Environment, 2001) guidelines. Total Cu concentrations ranged from 7.37μg/g to 73.6 μg/g (dw). Only Cu concentration in one lake exceeded the CCME guidelines besides having the highest mean concentration among all. Total Zn concentrations ranged from 107 μg/g to 529 μg/g (dw). Again, The Zn concentrations in three lakes were found to exceed CCME guidelines for Zn concentration in freshwater sediment. Geochemical study on sediment revealed that nonresistant fractions for Cd, Cu and Zn for other lakes there Cu and Zn indicated that lakes in the park, especially near oxidation pond and monsoon drains, could have received anthropogenic metals from domestic wastes. Rehabilitation program and regular biomonitoring at Kelana Jaya Lakes are therefore recommended.

  18. Investigation of phases in Al23Co15Cr23Cu8Fe15Ni16 and Al8Co17Cr17Cu8Fe17Ni33 high entropy alloys and comparison with equilibrium phases predicted by Thermo-Calc

    International Nuclear Information System (INIS)

    Highlights: ► High entropy alloys are investigated by three dimensional atom probe. ► The brittle Al23Co15Cr23Cu8Fe15Ni16 alloy decomposes into two body centred cubic phases. ► Ductile Al8Co17Cr17Cu8Fe17Ni33 shows two prominent face-centred cubic phases. ► Results are compared with equilibrium phases predicted by Thermo-Calc. -- Abstract: Al23Co15Cr23Cu8Fe15Ni16 and Al8Co17Cr17Cu8Fe17Ni33 high entropy alloys were investigated by scanning electron microscopy, transmission electron microscopy and three dimensional atom probe. While the brittle Al23Co15Cr23Cu8Fe15Ni16 alloy decomposes during solidification mainly into two body centred cubic phases, the ductile Al8Co17Cr17Cu8Fe17Ni33 shows two prominent face-centred cubic phases. Al23Co15Cr23Cu8Fe15Ni16 consists of Fe–Cr-rich and Cu-rich intermetallic phases embedded in an Al–Ni-rich solid solution matrix. The microstructure of Al8Co17Cr17Cu8Fe17Ni33 is mainly characterized by two phases. Nano-sized precipitates enriched mainly in Ni are embedded in a matrix depleted in Al and Cu. The phases observed in both high entropy alloys are compared with the equilibrium phases predicted by Thermo-Calc simulation

  19. 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

  20. The abrasive wear dependence research on chemical constitution, hardness and resistance of alloy cast steel Cr-Mo-V-Cu-Ni type

    International Nuclear Information System (INIS)

    In the work there are research program elements, alloying elements contents influence on abrasive wear for hot work. The aim of research is to define the hardness influence, resistance and contents of Cr, Mo, V on alloy cast steel abrasive wear Cr-Mo-V-Cu-Ni. (author)

  1. CuInSe2 and CdTe: Scale-up for manufacturing

    Science.gov (United States)

    Zweibel, Ken; Mitchell, Richard

    1989-12-01

    The information in this report was originally compiled to serve as a chapter in a photovoltaic reference book. The particular focus of this chapter was on the development of low-cost photovoltaic materials, namely CuInSe2 and CdTe, two leading polycrystalline thin film materials exhibiting high efficiencies and low production costs. Both materials demonstrate significant potential as usable technologies in the commercial market. While the primary focus of this review is on the characteristics of these materials, the authors also provide a look at key methods for making these materials as well as for making added layers that are required for completing a device. In addition, the authors discuss related issues to specific materials (e.g., availability, stability, toxicity) and to each approach (e.g., advantages and drawbacks).

  2. Greenhouse evaluation of EDTA effectiveness at enhancing Cd, Cr, and Ni uptake in Helianthus annuus and Thlaspi caerulescens

    Energy Technology Data Exchange (ETDEWEB)

    Munn, J.; January, M.; Cutright, T.J. [Dept. Civil Engineering, The Univ. of Akron, OH (United States)

    2008-04-15

    Background, aims and scope. Phytoremediation is a promising means for the treatment of heavy metal contamination. Although several species have been identified as hyperaccumulators, most studies have been conducted with only one metal. Experiments were conducted to investigate the ability of Helianthus annuus and Thlaspi caerulescens to simultaneously uptake Cd, Cr and Ni. Materials and methods. The efficiency of plants grown in a sandy-loam soil was investigated. The ability of two EDTA concentrations (0.1 and 0.3 g kg{sup -1}) for enhancing the phytoremediation of Cd, Cr and Ni at two different metal concentrations (24.75 mg kg{sup -1} and 90 mg kg{sup -1}) was studied. Results. Thlaspi hyperaccumulated Ni with 0.1 g kg{sup -1} EDTA. When the EDTA dosage was increased to 0.3 g kg{sup -1}, Thlaspi was able to hyperaccumulate both Ni and Cr. Since Thlaspi is a low-biomass plant, it was considered insufficient for full-scale applications. Helianthus annuus hyperacummulated Cr (with 0.1 g kg{sup -1} EDTA) and Cd (0.3 g kg{sup -1} EDTA). Discussion. When the contamination was 8.25 mg kg{sup -1} per metal, the total metal uptake was 10-25% (1.35 to 2.12 mg) higher and had the same uptake selectivity (Cr>>Cd>Ni) for both EDTA levels. It was hypothesized that complexation with EDTA interfered with Ni translocation. For these experiments, the optimal results were obtained with the H. annuus-0.1 g kg{sup -1} EDTA combination. Conclusions. Although the use of EDTA did increase the amount of metal that could be extracted, care should be taken during in-situ field applications. Chelators can also increase the amount of metals that are leached past the root zone. Metal leaching and subsequent migration could lead to ground water contamination as well as lead to new soil contamination. Recommendations and perspectives. Additional research to identify the optimal EDTA dosage for field applications is warranted. This is necessary to ensure that the metals do not leach past the

  3. Zn, Cu, Cd and Hg binding to metallothioneins in harbour porpoises Phocoena phocoena from the southern North Sea

    Directory of Open Access Journals (Sweden)

    Jauniaux Thierry

    2006-02-01

    Full Text Available Abstract Background Harbour porpoises Phocoena phocoena from the southern North Sea are known to display high levels of Zn and Hg in their tissues linked to their nutritional status (emaciation. The question arises regarding a potential role of metallothioneins (MTs with regard to these high metal levels. In the present study, metallothionein detection and associated Zn, Cd, Cu and Hg concentrations were investigated in the liver and kidney of 14 harbour porpoises collected along the Belgian coast. Results Metallothioneins seemed to play a key role in essential metal homeostasis, as they were shown to bind 50% of the total hepatic Zn and 36% of the total hepatic Cu concentrations. Renal MTs also participated in Cd detoxification, as they were shown to bind 56% of the total renal Cd. Hg was mainly found in the insoluble fraction of both liver and kidney. Concomitant increases in total Zn concentration and Zn bound to MTs were observed in the liver, whereas Zn concentration bound to high molecular weight proteins remained constant. Cu, Zn and Cd were accumulated preferentially in the MT fraction and their content in this fraction increased with the amount in the hepatocytosol. Conclusion MTs have a key role in Zn and Cu homeostasis in harbour porpoises. We demonstrated that increasing hepatic Zn concentration led to an increase in Zn linked to MTs, suggesting that these small proteins take over the Zn overload linked to the poor body condition of debilitated harbour porpoises.

  4. EFFECTS OF AQUEOUS AL, CD, CU, FE(II), NI, AND ZN ON PB IMMOBILIZATION BY HYDROXYAPATITE

    Science.gov (United States)

    The effects of aqueous Al, Cd, Cu, Fe(II), Ni, or Zn on Pb immobilization by hydroxyapatite (Ca10(PO4),(OH)2) were studied. ead was removed mainly via hydroxyapatite dissolution and hydroxypyromorphite (Pb10(PO4)6(OH)2) precipitation in the presence of these metals with a Pb remo...

  5. Crystal structures of low- and high-temperature modifications of Cu{sub 2}CdGeSe{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Gulay, L.D.; Romanyuk, Ya.E.; Parasyuk, O.V

    2002-12-16

    The Cu{sub 2}CdGeSe{sub 4} compound melts incongruently at 1103 K and shows a polymorphous transformation. The crystal structures of both (LT and HT) modifications of the Cu{sub 2}CdGeSe{sub 4} compound were determined using X-ray powder and single crystal diffraction, respectively. The LT-Cu{sub 2}CdGeSe{sub 4} has a tetragonal structure (space group I4-bar 2m, a=0.57482(2), c=1.10533(3) nm, R{sub I}=0.0571 in the isotropic approximation). The HT-Cu{sub 2}CdGeSe{sub 4} crystallizes in the orthorhombic space group Pmn2{sub 1} (lattice parameters a=0.80968(9), b=0.68929(6) and c=0.66264(6) nm, R{sub F}=0.0446 in the anisotropic approximation). Some peculiarities of the tetragonal{r_reversible}orthorhombic structure transformation are discussed.

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

    International Nuclear Information System (INIS)

    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)

  7. Experimental and modeling of the electrodialytic and dialytic treatment of a fly ash containing Cd, Cu and Pb

    DEFF Research Database (Denmark)

    Lima, A.T.; Ribeiro, A.B.; Rodriguez-Maroto, J.M.;

    2010-01-01

    A one-dimensional model is developed for simulating the electrodialytic and dialytic treatment of a fly ash containing cadmium, copper and lead. Two experimental systems have been used, a column of ash and a stirred ash suspension. The movement of Cd, Cu and Pb has been modeled taking into accoun...

  8. Removal of Cu and Cr from an industrial effluent using a packed-bed column with algae Gelidium-derived material

    OpenAIRE

    Vilar, Vitor; Martins, Ramiro; Botelho, Cidália; Boaventura, Rui

    2009-01-01

    The purpose of this work was to evaluate the potential of algal waste from the agar extraction industry,immobilized in a polymer, and the algae Gelidium itself, the raw material of agar extraction, to remove Cu(II)and Cr(III) from industrial ef#64258;uents. The study involved a Cu(II) bearing ef#64258;uent and the mixture of this ef#64258;uentwith an ef#64258;uent containing Cr(VI), previously reduced to Cr(III). The two ef#64258;uents were collected from metalplating plants, and then#64257;l...

  9. Single-Electron Detachment Cross Sections for Transition-Element Negative Ions Ti-,Cr-, Cu- in Collision with N2

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong-Yi; ZHANG Xue-Mei; WU Shi-Min; LI Guang-Wu; LU Fu-Quan

    2004-01-01

    @@ Single-electron detachment (SED) cross sections for Cr- and Ti- in collision with N2 have been obtained in the energy region of 10-30 ke V, for the first time to our knowledge. In the present energy range, the magnitude of the Cr- +N2 and Fe- +N2 SED cross sections is larger than that of Cu- +N2. It is also found that the cross sections for Cr- and Ti- in collisions with N2 exhibit different dependences on anion impact velocity from that of Cu-.

  10. Microstructure Evolution in a Cu-0.5Cr-0.2Zr Alloy Subjected to Equal Channel Angular Pressing, Rolling or Aging

    Science.gov (United States)

    Alexandrov, Igor V.; Sitdikov, Vil D.; Abramova, Marina M.; Sarkeeva, Elena A.; Wei, Kun Xia; Wei, Wei

    2016-08-01

    The evolution of microstructure in the Cu-0.5%Cr-0.2%Zr alloy subjected to thermomechanical treatment has been studied by means of the x-ray analysis. The workpieces have been subjected to 1, 2, 4 and 8 passes of equal channel angular pressing, plain cold rolling and aging treatment. The results of the XRD investigations reflect the evolution of the lattice parameter, the size of coherently scattering domains, the elastic microdistortions and the dislocation density in Cu matrix. The observed changes in the microstructure are explained by the competition between the developing defects and precipitation of the Cr phase particles from the Cu matrix.

  11. Sodium polyacrylate as a binding agent in diffusive gradients in thin-films technique for the measurement of Cu2+ and Cd2+ in waters.

    Science.gov (United States)

    Fan, Hongtao; Sun, Ting; Li, Weijia; Sui, Dianpeng; Jin, Shuang; Lian, Xiaojing

    2009-10-15

    An aqueous solution containing sodium polyacrylate (PA, 0.0030M) was used in diffusive gradients in thin-films technique (DGT) to measure DGT-labile Cu(2+) and Cd(2+) concentrations. The DGT devices (PA DGT) were validated in four types of solutions, including synthetic river waters containing metal ions with or without complexing EDTA, natural river water (Hun River, Shenyang, China) spiked with Cu(2+) and Cd(2+), and an industrial wastewater (Shenyang, China). Results showed that only free metal ions were measured by PA DGT, recovery=98.79% for Cu(2+) and recovery=97.80% for Cd(2+) in solutions containing only free metal ions, recovery=51.02% for Cu(2+) and recovery=51.92% for Cd(2+) in solution with metal/EDTA molar ratio of 2:1 and recovery=0 in solutions with metal/EDTA molar ratio of 1:1 and 1:2. These indicated that the complexes of Cu-EDTA and Cd-EDTA were DGT-inert or not DGT-labile. The DGT performance in spiked river water (recovery=8.47% for Cu(2+) and recovery=27.48% for Cd(2+)) and in industrial wastewater (recovery=14.16% for Cd(2+)) were also investigated. Conditional stability constants (logK) of PA-Cu and PA-Cd complexes were determined as 6.98 and 5.61, respectively, indicating strong interaction between PA and the metals. PMID:19635351

  12. Multi-metal interactions between Cd, Cu, Ni, Pb and Zn in water flea Daphnia magna, a stable isotope experiment

    Energy Technology Data Exchange (ETDEWEB)

    Komjarova, I. [Department of Biology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)], E-mail: Irina.Komjarova@ua.ac.be; Blust, R. [Department of Biology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2008-11-11

    Metal interaction effects were investigated in Daphnia magna during a simultaneous exposure to essential (Cu, Ni and Zn) and non-essential (Cd and Pb) metals at environmentally relevant concentrations using a stable isotope technique. The metals were applied in the following concentration ranges: 0.0125-0.2 {mu}M for {sup 106}Cd, 0.025-0.25 {mu}M for {sup 65}Cu and {sup 204}Pb, 0.1-1.25 {mu}M for {sup 62}Ni and {sup 67}Zn. Cadmium and copper exhibited a suppressing effect on the uptake rates of all other metals present in the mixture with the exception to lead at all studied concentrations. The effect was already pronounced at low Cd and Cu concentrations and reached a maximum at the higher concentrations. Nickel and zinc showed weaker interactions with cadmium and between each other, while having no effect on copper and lead uptake. There was a high degree of correlation between Cd, Ni and Zn uptake rates indicating that these metals share in part common uptake or interaction pathways. Moreover, a significant correlation between Zn and Cu uptake processes suggests that more than one mechanism is involved in Zn accumulation since Cu is known to interact with Na uptake sites. The uptake of lead was marked by a high initial rate, but the uptake process reached saturation within 24 h. Cd applied at a concentration of 0.2 {mu}M was the only metal which affected the lead uptake process by stimulation of the Pb uptake. Added to the medium at a concentration of 0.25 {mu}M, lead in turn, increased copper uptake. Current work illustrates that metal interactions are significant and occur at low environmentally realistic concentrations affecting bioavailability of both toxic and essential metals.

  13. Multi-metal interactions between Cd, Cu, Ni, Pb and Zn in water flea Daphnia magna, a stable isotope experiment

    International Nuclear Information System (INIS)

    Metal interaction effects were investigated in Daphnia magna during a simultaneous exposure to essential (Cu, Ni and Zn) and non-essential (Cd and Pb) metals at environmentally relevant concentrations using a stable isotope technique. The metals were applied in the following concentration ranges: 0.0125-0.2 μM for 106Cd, 0.025-0.25 μM for 65Cu and 204Pb, 0.1-1.25 μM for 62Ni and 67Zn. Cadmium and copper exhibited a suppressing effect on the uptake rates of all other metals present in the mixture with the exception to lead at all studied concentrations. The effect was already pronounced at low Cd and Cu concentrations and reached a maximum at the higher concentrations. Nickel and zinc showed weaker interactions with cadmium and between each other, while having no effect on copper and lead uptake. There was a high degree of correlation between Cd, Ni and Zn uptake rates indicating that these metals share in part common uptake or interaction pathways. Moreover, a significant correlation between Zn and Cu uptake processes suggests that more than one mechanism is involved in Zn accumulation since Cu is known to interact with Na uptake sites. The uptake of lead was marked by a high initial rate, but the uptake process reached saturation within 24 h. Cd applied at a concentration of 0.2 μM was the only metal which affected the lead uptake process by stimulation of the Pb uptake. Added to the medium at a concentration of 0.25 μM, lead in turn, increased copper uptake. Current work illustrates that metal interactions are significant and occur at low environmentally realistic concentrations affecting bioavailability of both toxic and essential metals

  14. Development of CVD-W coatings on CuCrZr and graphite substrates with a PVD intermediate layer

    International Nuclear Information System (INIS)

    In order to apply tungsten (W) coatings by chemical vapor deposition (CVD) for repairing or updating the plasma facing components (PFCs) of the first wall and divertor in existing or future tokomaks, where CuCrZr or graphite is the substrate material, an intermediate layer by physical vapor deposition (PVD) has been used to accommodate the interface stress due to the mismatch of thermal expansion or act as a diffusion barrier between the CVD-W coating and the substrate. The prepared CuCrZr/PVD-Cu/CVD-W sample with active cooling has passed thermal fatigue tests by electron beam with an absorbed power of 2.2 MW/m2, 50 s on/50 s off, for 100 cycles. Another graphite/PVD-Si/CVD-W sample without active cooling underwent thermal fatigue testing with an absorbed power density of 4.62 MW/m2, 5 s on/25 s off, for 200 cycles, and no catastrophic failure was found

  15. 添加助剂的低铬Cu-Cr-Si催化剂和甲酸甲酯氢解制甲醇%Study of the Effect of Additives on Cu-Cr-Si Catalyst for Methanol Synthesis from the Hydrogenolysis of Methyl Formate

    Institute of Scientific and Technical Information of China (English)

    龙毅; 储伟; 叶扬红

    2003-01-01

    通过对低铬Cu-Cr-Si催化剂以及添加了不同助剂的低铬Cu-Cr-Si催化剂用于甲酸甲酯氢解反应的性能研究,发现助剂B、Zr、Ca、Ba、Mg能够有效地提高低铬Cu-Cr-Si催化剂的活性.并采用TPR、XRD等手段对催化剂进行了表征.

  16. Structural and magnetic effects of Cd{sub 1-x}In{sub x}Cr{sub 2}Se{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Behera, P. Suchismita; Bhobe, P. A., E-mail: pbhobe@iiti.ac.in [School of Basics Sciences, Indian Institute of Technology Indore, Khandwa Road, Indore-452017 (India); Nigam, A. K. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400 005 (India)

    2015-06-24

    Polycrystalline CdCr{sub 2}Se{sub 4} spinels with non-magnetic indium substitution were investigated with an aim to study the influence of non-magnetic substitution at the Cd site on its structural and magnetic properties. We carried out powder XRD and magnetic measurements on three compositions: Cd{sub 1-x}In{sub x}Cr{sub 2}Se{sub 4} (x=0, 0.05, 0.1). The XRD patterns were analyzed by carrying out Rietveld analysis and structural parameters were estimated. Phase purity of the compounds using reitveld refinement technique where confirming the indium distribution at tetrahedral site of the cubic close-packed sublattice formed by the selenium ions. The chemical compositions of these compounds were determined by energy dispersive x-ray analysis. Compared to parent compound, CdCr{sub 2}Se{sub 4}, the ferromagnetic Curie temperature T{sub C} was found to decrease from 130K to 123K and 114K as x varied from 0 to 0.05 and 0.1 respectively, whereas the saturation magnetization increases in Cd{sub 0.95}In{sub 0.05}Cr{sub 2}Se{sub 4} and again decreases in Cd{sub 0.9}In{sub 0.1}Cr{sub 2}Se{sub 4}.

  17. Facile synthesis of spinel CuCr2O4 nanoparticles and studies of their photocatalytic activity in degradation of some selected organic dyes

    International Nuclear Information System (INIS)

    Copper chromite (CuCr2O4) 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 N2 adsorption-desorption isotherm (BET). The XRD pattern revealed formation of tetragonal body-centered CuCr2O4 and TEM image showed quasi-spherical particles of size 5–35 nm. The photocatalytic activity of CuCr2O4 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 H2O2 under solar irradiation. The CuCr2O4 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: • CuCr2O4 nanoparticles were synthesized by urea assisted co-precipitation followed by calcination. • The XRD pattern revealed formation of tetragonal body-centered CuCr2O4. • The TEM images showed the material to be quasi-spherical in shape with sizes 5–35 nm. • CuCr2O4 nanoparticles exhibited pronounced photocatalytic activity

  18. Sonochemical synthesis and characterization of urchin-like Cu{sub 3}CrO{sub 6}·2H{sub 2}O nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying; Yang, Xiao-Dong; Mao, Chang-Jie, E-mail: maochangjie@sina.com; Song, Ji-Ming; Niu, He-Lin; Zhang, Sheng-Yi

    2014-12-15

    Urchin-like Cu{sub 3}CrO{sub 6}·2H{sub 2}O nanostructures have been successfully synthesized via a facile and fast sonochemical route. The composition, morphology and size of the as-obtained product were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HRTEM). These results showed that the as-synthesized Cu{sub 3}CrO{sub 6}·2H{sub 2}O urchins have average diameters of 1 μm and an individual urchin sphere is composed of numerous small nanowires. Typical Cu{sub 3}CrO{sub 6}·2H{sub 2}O nanowires have diameters of 5 nm. Studies found that ethylenediamine tetraacetic acid disodium salt (EDTA) plays an important role to determine the morphology of the products. The self-assembly and oriented attachment procedure has been proposed for the possible formation mechanism. The Brunauer-Emmett-Teller (BET) surface area of the urchin-like nanostructures calculated from the nitrogen adsorption–desorption isotherm is about 78 m{sup 2} g{sup −1}. Additionally, room-temperature photoluminescence of the Cu{sub 3}CrO{sub 6}·2H{sub 2}O with different morphologies has also been investigated. - Highlights: • Urchin-like Cu{sub 3}CrO{sub 6}·2H{sub 2}O nanostructures have been successfully synthesized. • Urchin-like Cu{sub 3}CrO{sub 6}·2H{sub 2}O nanostructures are composed of hundreds of nanowires. • A possible growth mechanism was discussed. • Room-temperature photoluminescence of the Cu{sub 3}CrO{sub 6}·2H{sub 2}O with different morphologies has also been investigated.

  19. 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.

  20. Health Risk Assessment of Consumption of Tea marketed in Hamadan City, Potential Risk of As, Pb, Cd and Cr

    Directory of Open Access Journals (Sweden)

    S. Sobhan Ardakani

    2016-04-01

    Full Text Available Introduction & Objective: Tea is the most popular beverage in the world and contains several essential nutrients, which are beneficial for human health. Because the contamination of tea leaves by heavy metals may pose a serious threat to human, this study was carried out for analysis and health risk assessment of As, Pb, Cd and Cr in some black and green tea brand samples marketed in Hamadan City in 2015. Materials & Methods: After collection and preparation of 3 brands from each of cultivated and imported black and green tea specimens with acid digestion method in the laboratory, the concentrations of elements in samples were determined using Atomic Absorption Spectrophotometery in 3 replications. Also, all statistical analyses were performed using the SPSS statistical package. Results: The results showed that the maximum mean concentrations of As,Pb,Cd and Cr were as follows : As 0.34±0.54 µg kg-1 in imported green tea, Pb, Cd 577.0±608.0, 37.0±15.0 in domestic green tea respectively, and Cr 165.0±114.0 iimported black tea samples, and significantly lower than WHO and ISIRI permissible limits. Conclusion: Although consumption of tea has not any adverse effects on the consumers’ health, due to the increased use of agricultural inputs, sewage sludge and wastewater by farmers regular periodic monitoring of chemical pollutants content specially heavy metals in foodstuffs are recommended for food safety. (Sci J Hamadan Univ Med Sci 2016; 23 (1:65-74

  1. PET Imaging of CD105/Endoglin Expression with a 61/64Cu-Labeled Fab Antibody Fragment

    Science.gov (United States)

    Zhang, Yin; Hong, Hao; Orbay, Hakan; Valdovinos, Hector F.; Nayak, Tapas R.; Theuer, Charles P.; Barnhart, Todd E.; Cai, Weibo

    2013-01-01

    Purpose The goal of this study was to generate and characterize the Fab fragment of TRC105, a monoclonal antibody that binds with high affinity to human and murine CD105 (i.e. endoglin), and investigate its potential for positron emission tomography (PET) imaging of tumor angiogenesis in a small animal model after 61/64Cu-labeling. Methods TRC105-Fab was generated by enzymatic papain digestion. The integrity and CD105 binding affinity of TRC105-Fab was evaluated before NOTA (i.e., 1,4,7-triazacyclononane-1,4,7-triacetic acid) conjugation and 61/64Cu-labeling. Serial PET imaging and biodistribution studies were carried out in the syngeneic 4T1 murine breast cancer model to quantify tumor targeting efficacy and normal organ distribution of 61/64Cu-NOTA-TRC105-Fab. Blocking studies with unlabeled TRC105 were performed to confirm CD105 specificity of the tracer in vivo. Immunofluorescence staining was also conducted to correlate tracer uptake in the tumor and normal tissues with CD105 expression. Results TRC105-Fab was produced with high purity through papain digestion of TRC105, as confirmed by SDS-PAGE, HPLC analysis, and mass spectrometry. 61/64Cu-labeling of NOTA-TRC105-Fab was achieved with ~50% yield (specific activity: ~44 GBq/µmol). PET imaging revealed rapid uptake of 64Cu-NOTA-TRC105-Fab in the 4T1 tumor (3.6 ± 0.4, 4.2 ± 0.5, 4.9 ± 0.3, 4.4 ± 0.7, and 4.6 ± 0.8 %ID/g at 0.5, 2, 5, 16, and 24 h post-injection respectively; n = 4). Since tumor uptake peaked soon after tracer injection, 61Cu-labeled TRC105-Fab was also able to provide tumor contrast at 3 and 8 h post-injection. CD105 specificity of the tracer was confirmed with blocking studies and histological examination. Conclusion Herein we report PET imaging of CD105 expression with 61/64Cu-NOTA-TRC105-Fab, which exhibited prominent and target specific uptake in the 4T1 tumor. The use of a Fab fragment led to much faster tumor uptake (which peaked at a few hours after tracer injection) compared to

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

    OpenAIRE

    Calero, M.; F. Hernáinz; Blázquez, G; M. A. Martín-Lara; G. Tenorio

    2009-01-01

    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 th...

  3. Effects of Fe 2+ substitution on magnetic and dielectric properties of CdCr2S4

    Institute of Scientific and Technical Information of China (English)

    Yan Li-Qin; Sun Yang; He Lun-Hua; Wang Fang-Wei; Shen Jun

    2011-01-01

    The magnetic and dielectric properties of polycrystalline Cd1-xFexCr2S4(0 ≦x≦0.9) are investigated. Upon substitution of Cd by Fe,the Curie temperature (Tc) is increased while the saturation magnetization is decreased.A low doping level of Fe increases the permittivity,while a high doping level decreases the permittivity,which is explained by the internal barrier layer capacitor model. Kinks are observed in the temperature-dependent permittivity and loss tangent near Tc for the samples with x=0.5,0.7,0.9,implying the existence of the magnetodielectric effect.Furthermore,with the increase of Fe content,a decrease of anomaly deviation rate induced by internal molecular field is revealed in the permittivity,while an increase is observed for the loss tangent.

  4. Retention and distribution of Cu, Pb, Cr, and Zn in a full-scale hybrid constructed wetland receiving municipal sewage.

    Science.gov (United States)

    Xiao, Haiwen; Zhang, Shengli; Zhai, Jun; He, Qiang; Mels, Adriaan; Ning, Kejia; Liu, Jie

    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 metal concentrations in water, sediments, and plant tissues in the hybrid CW were analysed. The removal of heavy metals from the water stream in the monitoring period was not statistically significant. Metal concentrations in the sediments generally decreased along the wastewater treatment process. The reductive anaerobic condition in the VBFW may promote the sulphate reduction and form highly insoluble Cu, Pb, and Zn sulphides, resulting in the higher concentration of the bivalent cations in the VBFW sediments than the corresponding values in the HSSF; however, the aerobic and anoxic environments in the HSSF enhanced the removal of Cr with the co-precipitation of iron and manganese oxides, and their hydroxides. Metal concentrations in plant tissues were not significantly influenced by the concentrations in sediments, while roots contained statistically higher metal concentrations than stems and leaves. The sediments stored 94.01, 86.31, 95.85, and 89.51% of the total Cu, Pb, Cr, and Zn retained in the hybrid CW system, respectively, while only small fractions (<10%) were accumulated in the harvestable macrophyte tissues. It is important to clean not only the accessible sediments in free water surface tank and ponds but also the embedded sediments in vegetated beds for the sustainable removal of heavy metals. PMID:23676396

  5. Synthesis protocol and superconducting properties of (Hg,Cr)Sr{sub 2}CuO{sub 4+{delta}}

    Energy Technology Data Exchange (ETDEWEB)

    Balamurugan, S [Superconducting Materials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Selvam, P [Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai, 400 076 (India)

    2005-03-01

    In this paper, we report the study of our results on the synthesis protocol and the superconducting properties of (Hg,Cr)Sr{sub 2}CuO{sub 4+{delta}}. We have used several distinct approaches for the synthesis of good quality (Hg, Cr)/Sr-1201 samples by varying the processing parameters such as starting materials, precursor and annealing treatments as well as the sample container. The (Hg, Cr)/Sr-1201 samples were synthesized in partial vacuum, and systematically characterized by powder XRD, {chi}-T, dc-electrical-resistance and dc-magnetization measurements. XRD data confirm that they are of tetragonal Hg/Ba-1201 type structure. Good quality (Hg, Cr)/Sr-1201 samples were obtained from the sample prepared using a strontium nitrate source with a maximum T{sub c}{sup onset} {approx} 60 K, which is higher than the samples prepared using a carbonate source T{sub c}{sup onset} {approx} 56 K). It is found that T{sub c} is not affected by the subsequent Ar or O{sub 2} annealing treatment. Remarkably, the annealed samples show significant improvement in the diamagnetic transition.

  6. Effect of annealing treatment on microstructure and properties of high-entropy FeCoNiCrCu0.5 alloy

    International Nuclear Information System (INIS)

    Highlights: → Microstructural, thermal and corrosion property evolution of high entropy FeCoNiCrCu0.5 alloy at annealing treatment were studied. → Microstructure with annealing process induces a spinodal decomposition reaction which the amount of Cu-rich phase in the annealing microstructure changed; this phase transformed into a Cr-rich phase with an increase in annealing temperature from 350 to 1250 deg. C microstructure show BEI image in the SEM, and TEM. → The thermal property analysis revealed that in the as-cast high-entropy FeCoNiCrCu0.5 alloy specimen annealed below 1300 deg. C, the Cu-rich (Cu-(Ni, Co, Cr, Fe)) phase precipitated in the matrix by spinodal decomposition. → The corrosion potential and pitting potential of the FeCoNiCrCu0.5 alloy when immersed in a 3.5 wt% NaCl solution in the main corrosion mechanism were studied. → Cl- ions preferentially attacked the Cu-rich phase. - Abstract: This study examined the microstructure and electrochemical corrosion behaviour of high-entropy FeCoNiCrCu0.5 alloys annealed at various temperatures. The alloy microstructures were characterized and analyzed chemically by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Further, the effects of annealing temperatures of 350 deg. C, 650 deg. C, 950 deg. C, and 1250 deg. C with a holding time of 24 h at each temperature on the alloy microstructure and properties were investigated. XRD spectra of the as-cast specimens and those heated to 1250 deg. C showed a face-centred cubic (FCC) solid-solution phase. All specimens contained a matrix, which included a Cu-depleted phase, a Cr-rich phase (second structure), and a Cu-rich phase (third structure). The Cr-rich phase precipitated in the matrix after annealing at 1250 deg. C. The microstructure of the Cu-rich phase showed spinodal decomposition with an increase in the annealing temperature from 350 deg. C to 1250 deg. C. Differential scanning calorimetry (DSC

  7. [Concentration of Hg, Pb, Cd, Cr and As in liver Carcharhinus limbatus (Carcharhiniformes: Carcharhinidae) captured in Veracruz, Mexico].

    Science.gov (United States)

    Mendoza-Díaz, Fernando; Serrano, Arturo; Cuervo-López, Liliana; López-Jiménez, Alejandra; Galindo, José A; Basañez-Muñoz, Agustin

    2013-06-01

    Pollution by heavy metals in marine ecosystems in the Gulf of Mexico is one of the hardest conservation issues to solve. Sharks as top predators are bioindicators of the marine ecosystem health, since they tend to bioaccumulate and biomagnify contaminants; they also represent a food source for local consumption. Thus, the objective of this study was to study the possible presence of heavy metals and a metalloid in livers of Carcharhinus limbatus. For this, a total of 19 shark livers were taken from animals captured nearby Tamihua, Veracruz, Mexico from December 2007 to April 2008. 12 out of the 19 captured sharks were males, one was an adult female, three were juvenile males, and three juvenile females. Four heavy metals (Hg, Pb, Cd, and Cr) and one metaloid (As) were analyzed in shark livers using an atomic absorption spectrophotometry with flame and hydride generator. Our results showed that the maximum concentrations found were: Hg = 0.69 mg/kg, Cd = 0.43 mg/kg, As = 27.37 mg/kg, Cr = 0.70 mg/kg. The minimum concentrations found were: As = 14.91 mg/kg, Cr = 0.35 mg/kg. The Pb could not be determined because the samples did not have the spectrophotometer minimum detectable amount (0.1 mg/kg). None of the 19 samples analyzed showed above the permissible limits established by Mexican and American laws. There was a correlation between shark size and Cr and As concentration (Pearson test). The concentration of Cr and As was observed to be higher in bigger animals. There was not a significant difference in heavy metals concentration between juveniles and adults; however, there was a difference between males and females. A higher Cr concentration was found in females when compared to males. None of the samples exceed the maximum limit established by the laws of Mexico and the United States of America. Much longer studies are needed with C. limbatus and other species caught in the region, in order to determine the degree of contaminants exposure in aquatic ecosystems

  8. Final report on in-reactor tensile tests on OFHC - Copper and CuCrZr alloy

    DEFF Research Database (Denmark)

    Singh, B.N; Edwards, D.J.; Tähtinen, S.;

    2004-01-01

    of uniaxial tensile tests on pure copper and a CuCrZr alloy in a fission reactor at 363 and 393K. In the following, we first describe the experiments and then present results illustrating the build up ofstress as a function of concurrently increasing strain and displacement dose level. Results on...... of the combination of strain and radiation hardening, the rate of hardening in the plastic regime is found tobe enhanced. The rate of hardening, the maximum level of hardening and the magnitude of the total elongation achieved during an in-reactor test are found to depend strongly on the pre...

  9. The Effect of Cr Substitution on the Electronic Structure of CuAl1-xCrxO2

    OpenAIRE

    WATSON, GRAEME WILLIAM; Morgan, Ben; Scanlon, David

    2009-01-01

    PUBLISHED The geometries and electronic structures of CuAl1?xCrxO2 have been investigated using density-functional theory with on-site corrections for strongly correlated systems (GGA+U) for x=0,(1/2),1. Al is found to be well described within the ionic model, with a valence charge corresponding to a +3 oxidation state. Substituting Cr for Al is predicted to increase the density of states at the top of the valence band, in agreement with experimental x-ray photoemission spectroscopy data. ...

  10. The influence of precursor quality on the superconducting properties of (Hg,Cr)Sr2CuO4+δ

    International Nuclear Information System (INIS)

    We have investigated the superconducting properties of (Hg,Cr)Sr2Cu O4+δ prepared using different precursor routes. It was observed that the quality of the samples depends strongly on the precursor quality and the nature of starting materials. The samples were synthesized in partial vacuum and characterized by XRD, FT-IR, χ-T and dc-magnetization. Good quality samples with high Tc (60 K) was obtained for the sample prepared from strontium nitrate as compared to strontium carbonate source (Tc = 56 K). (author)

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

    International Nuclear Information System (INIS)

    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

  12. Effect of small additions of Cu and Cr on crystallization of Fe80B9Si11 amorphous alloy

    International Nuclear Information System (INIS)

    By means of differential thermal and X-ray structure analyses, as well as, by measurement of microstrength one studied the effect of small additions of chromium and copper on the peculiarities of crystallization of Fe80B9Si11 amorphous alloy (Fe79Cr1B9Si11 and Fe79Cu1B9Si11). Chromium was determined to stabilize Fe3B nonequilibrium phase the formation of which resulted in eutectic type of crystallization at early stages while copper was determined to enable formation of α-Fe and Fe2B equilibrium phases and primary crystallization with precipitation of α-Fe primary crystals

  13. Multiferroic CuCrO2 under High Pressure: In-Situ X-Ray Diffraction and Raman Spectroscopic Studies

    OpenAIRE

    Garg, Alka B.; Mishra, A. K.; Pandey, K. K.; Sharma, Surinder M

    2014-01-01

    The compression behavior of delafossite compound CuCrO2 has been investigated by in-situ x-ray diffraction and Raman spectroscopic measurements upto 23.2 and 34 GPa respectively. X-ray diffraction data shows the stability of ambient rhombohedral structure upto ~ 23 GPa. Material shows large anisotropy in axial compression with c-axis compressibility, c= 1.2610-3(1) GPa-1 and a-axis compressibility, a= 8.9010-3(6) GPa-1. Our XRD data shows an irreversible broadening of diffraction peaks. Press...

  14. Recrystallization and development of cube texture in Ti and Ti+Cr added Ni-Fe-Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Manna, I. (Dept. of Metallurgical Engineering , I.I.T., Kharagpur (India)); Ray, R.K. (Dept. of Metallurgical Engineering, I.I.T., Kanpur (India)); Gupta, K.P. (Dept. of Metallurgical Engineering, I.I.T., Kanpur (India))

    1994-06-01

    The development of a sharp cube or [l brace]100[r brace]<100> texture in two Ti and Ti+Cr added Ni-Fe-Cu alloys is presented. Texture studies in deformed as well as recrystallized conditions have been carried out by both conventional pole figure and orientation distribution function analysis. Microstructural evolution in course of recrystallization texture development has been extensively studied with both optical and electron microscopes. Heavy cold deformation (97 to 98%) followed by annealing at 1050 C for 2 h has been found to optimize the conditions for the desired texture development. (orig.)

  15. Preparation and characterization of CuCrO{sub 2}/TiO{sub 2} heterostructure photocatalyst with enhanced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Dehua, E-mail: xiongdehua2010@gmail.com [State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070 (China); National Engineering Laboratory for Fiber Optic Sensing Technology, Wuhan University of Technology, Wuhan 430070 (China); Chang, Haimei; Zhang, Qingqing; Tian, Shouqin; Liu, Baoshun [State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070 (China); Zhao, Xiujian, E-mail: opluse@whut.edu.cn [State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070 (China)

    2015-08-30

    Graphical abstract: - Highlights: • p-CuCrO{sub 2}/n-TiO{sub 2} heterostructure photocatalysts were fabricated for the first time. • The p–n heterojunctions were formed between CuCrO{sub 2} nanoparticle and TiO{sub 2} nanorod. • The degradation activity of CuCrO{sub 2}/TiO{sub 2} was much higher than that of pure TiO{sub 2}. • CuCrO{sub 2}/TiO{sub 2} has better separation efficiency of photogenerated electron and hole. - Abstract: A series of novel p-type CuCrO{sub 2}/n-type TiO{sub 2} heterostructure photocatalysts were fabricated for the first time by depositing CuCrO{sub 2} nanoparticles on TiO{sub 2} nanorod-array film through a facile spin-coating method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and photocurrent response were employed to characterize the as-synthesized composites. The photocatalytic activity of CuCrO{sub 2}/TiO{sub 2} for degradation of methylene blue (MB) aqueous solution was much higher than pure TiO{sub 2}, which could be ascribed to the formation of p–n heterojunctions between CuCrO{sub 2} nanoparticles and TiO{sub 2} nanorods. In particular, the best degradation efficiency of CuCrO{sub 2}/TiO{sub 2} heterojunction was 85.3%, about 1.14 times higher than pure TiO{sub 2} (74.6%), which could be attributed to their high separation efficiency of photogenerated electrons and holes. It is expected this strategy of p–n junction for enhancing photocatalytic activity can have considerable impact to promote the development of high efficient photocatalyst and industrial application for degrading pollutant, treating waste water and other environmental protection fields.

  16. Superior stability of ultra thin CdTe solar cells with simple Cu/Au back contact

    International Nuclear Information System (INIS)

    Due to its high scalability and low production cost, CdTe has shown a significant potential for high mass production, resulting to be one of the cheapest photovoltaic technologies available. Efficiencies exceeding 20% have been obtained by the application of high temperature CdTe deposition. However tellurium scarcity is a limitation for mass production and one of the possibilities to overcome this is the reduction of absorber thickness. We have already demonstrated efficiencies above 11% for devices with 1.5 μm thick CdTe. Nowadays we have fabricated ultra-thin absorber devices performing more than 13% efficiencies. But what is most interesting is that we have observed a different electrical operation and stability, connected to the fact that the depletion region takes a very large part of the device. In this work many CdTe solar cells with a standard Cu/Au back contact, made with different absorber thicknesses, were prepared, stored in dark and tested at different aging times, showing different reactions to the aging and in particular a remarkable stability as CdTe thickness reduces. - Highlights: • CdTe/CdS devices with 0.7, 1 and 1.8 μm thick absorbers have been prepared. • Superior stability in dark aging of ultra thin CdTe devices has been registered. • Electrical analysis shows different behaviors and nature of defects for thin CdTe samples. • For 6 μm CdTe samples degradation is driven mainly by defect compensation. • For ultra thin CdTe samples, degradation is dominated by impurities from the front contact

  17. Superior stability of ultra thin CdTe solar cells with simple Cu/Au back contact

    Energy Technology Data Exchange (ETDEWEB)

    Rimmaudo, Ivan; Salavei, Andrei; Xu, Bing Lei; Di Mare, Simone; Romeo, Alessandro, E-mail: alessandro.romeo@univr.it

    2015-05-01

    Due to its high scalability and low production cost, CdTe has shown a significant potential for high mass production, resulting to be one of the cheapest photovoltaic technologies available. Efficiencies exceeding 20% have been obtained by the application of high temperature CdTe deposition. However tellurium scarcity is a limitation for mass production and one of the possibilities to overcome this is the reduction of absorber thickness. We have already demonstrated efficiencies above 11% for devices with 1.5 μm thick CdTe. Nowadays we have fabricated ultra-thin absorber devices performing more than 13% efficiencies. But what is most interesting is that we have observed a different electrical operation and stability, connected to the fact that the depletion region takes a very large part of the device. In this work many CdTe solar cells with a standard Cu/Au back contact, made with different absorber thicknesses, were prepared, stored in dark and tested at different aging times, showing different reactions to the aging and in particular a remarkable stability as CdTe thickness reduces. - Highlights: • CdTe/CdS devices with 0.7, 1 and 1.8 μm thick absorbers have been prepared. • Superior stability in dark aging of ultra thin CdTe devices has been registered. • Electrical analysis shows different behaviors and nature of defects for thin CdTe samples. • For 6 μm CdTe samples degradation is driven mainly by defect compensation. • For ultra thin CdTe samples, degradation is dominated by impurities from the front contact.

  18. Development of a computer model for polycrystalline thin-film CuInSe sub 2 and CdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Gray, J.L.; Schwartz, R.J.; Lee, Y.J. (Purdue Univ., Lafayette, IN (United States))

    1992-04-01

    This report describes work to develop a highly accurate numerical model for CuInSe{sub 2} and CdTe solar cells. ADEPT (A Device Emulation Program and Toolbox), a one-dimensional semiconductor device simulation code developed at Purdue University, was used as the basis of this model. An additional objective was to use ADEPT to analyze the performance of existing and proposed CuInSe{sub 2} and CdTe solar cell structures. The work is being performed in two phases. The first phase involved collecting device performance parameters, cell structure information, and material parameters. This information was used to construct the basic models to simulate CuInSe{sub 2} and CdTe solar cells. This report is a tabulation of information gathered during the first phase of this project on the performance of existing CuInSe{sub 2} and CdTe solar cells, the material properties of CuInSr{sub 2}, CdTe, and CdS, and the optical absorption properties of CuInSe{sub 2}, CdTe, and CdS. The second phase will entail further development and the release of a version of ADEPT tailored to CuInSe{sub 2} and CdTe solar cells that can be run on a personal computer. In addition, ADEPT will be used to analyze the performance of existing and proposed CuInSe{sub 2} and CdTe solar cell structures. 110 refs.

  19. Purification of Organic Wastewater Containing Cu2+ and Cr3+ by a Combined Process of Micro Electrolysis and Biofilm

    Institute of Scientific and Technical Information of China (English)

    李天成; 姜斌; 冯霞; 王大为; 袁绍军; 李鑫钢

    2003-01-01

    A complex process of micro electrolysis and biofilm was developed to continuously treat organic wastew-aters containing heavy metal ions such as Cu2+ and Cr3+,and the relevant purifying mechanism was also addressed. In detail,organic materials in wastewater could be consumed as nutritious source by biofilm composed of aerobes and anaerobes,However,for heavy metal ions (Cu2+,Cr3+),part was removed by electrodeposition,and some was adorbed on biofilm.In order to compare with the combined process of micro electrolysis and biofilm,the experimental data of micro electrolysis process (intermittent )or biofilm process (continuous)were provided,and the kinetic data of C6H12O6(glucose)biodegradation by cultured microbes or acclimated microbes were also obtained,These experimental results indicated that for wastewater initially consisted of C6H12O6(500 mg.L-1),Cu2+ and Cr3+(10mg.L6-1),after treatment,its concentrations of C6H12O6,Cu2+ and Cr3+ were lowered to the leve of 55-65 mg.L-1),after treatment,its concentrations of C6H12O6,Cu2+ and Cr3+ were lowered to the level of 55-65 mg.L-1,and less than 1mg.L-1,respectively,And the industrial reused water standards could be met by treated wastewater.

  20. 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)

    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. - 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

  1. 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.

  2. Structural and Photoelectrochemical Properties of Cu-Doped CdS Thin Films Prepared by Ultrasonic Spray Pyrolysis

    Directory of Open Access Journals (Sweden)

    Rui Xie

    2013-01-01

    Full Text Available Cu-doped CdS thin films of variable doping levels have been deposited on indium tin oxide-coated glass substrate by simple and cost-effective ultrasonic spray pyrolysis. The influences of doping concentration and annealing treatment on the structure and photoelectrochemical properties of the films were investigated. The deposited films were characterized by XRD, SEM, and UV-Vis spectra. Moreover, the films were investigated by electrochemical and photoelectrochemical measurements with regard to splitting water for solar energy conversion. The results showed that the Cu impurity can cause a structural change and red shift of absorption edge. It was found that the photocurrent can be improved by the Cu-doping process for the unannealed films under the weak illumination. The unannealed 5 at.% Cu-doped sample obtained the maximum IPCE, which achieved about 45% at 0.3 V versus SCE potential under 420 nm wavelength photoirradiation. In addition, the p-type CdS was formed with a doping of 4 at.%~10 at.% Cu after 450°C 2 h annealed in vacuum.

  3. Microstructure, thermodynamics and compressive properties of AlCoCrCuMn-x (x=Fe, Ti) high-entropy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaoqin, E-mail: wzqpapers@126.com [School of Railway Technology, Lanzhou Jiaotong University, Lanzhou 730010 (China); Wang, Xiaorong [School of Mechatronic Engineering, Lanzhou Jiaotong University, Lanzhou 730010 (China); Yue, Hui [School of Railway Technology, Lanzhou Jiaotong University, Lanzhou 730010 (China); Shi, Guangtian; Wang, Shunhua [School of Mechatronic Engineering, Lanzhou Jiaotong University, Lanzhou 730010 (China)

    2015-03-11

    Two equiatomic high-entropy alloys (HEAs), AlCoCrCuMnFe and AlCoCrCuMnTi, were produced by vacuum arc melting. Their microstructure, thermodynamics and mechanical properties were investigated in as-cast condition. The AlCoCrCuMnFe alloy is comprised of a face centered cubic (FCC) phase and two body centered cubic (BCC) phases, while the AlCoCrCuMnTi alloy consists of the intermetallics-base solid solution (AlCu{sub 2}Mn-like phase) besides a FCC phase and two BCC phases. Through analyzing the thermodynamics of equiatomic multicomponent alloys, two parameters, k{sub n} and φ, were proposed. The parameter k{sub n} is a function of n (n – the number of the components in an alloy system), while φ is defined as a parameter of T{sub sum} over |H{sub sum}| (T{sub sum} – the sum of every elemental melting point in an alloy system, |H{sub sum}| – the sum of mixing enthalpies of different pairs of alloying elements). φ≥1.1/k{sub n} is equivalent to Ω≥1.1 proposed by Yang to predict high entropy stabilized solid solution in equiatomic multicomponent alloys and more convenient to calculate. Compressive properties of the two HEAs together with their hardness have been investigated. Comparing to AlCoCrCuMnFe alloy, AlCoCrCuMnTi alloy has higher Vickers hardness, yield strength and compressive strength, but lower ultimate strain.

  4. Effects of acid rain on competitive releases of Cd, Cu, and Zn from two natural soils and two contaminated soils in hunan, China

    OpenAIRE

    Liao, Bo-han; Guo, Zhao-hui; Zeng, Qingru; Probst, Anne; Probst, Jean-Luc

    2007-01-01

    Leaching experiments of rebuilt soil columns with two simulated acid rain solutions (pH 4.6– 3.8) were conducted for two natural soils and two artificial contaminated soils from Hunan, southcentralChina, to study effects of acid rain on competitive releases of soil Cd, Cu, and Zn. Distilled water was used in comparison. The results showed that the total releases were Zn>Cu>Cd for the natural soils and Cd>Zn≫Cu for the contaminated soils, which reflected sensitivity of these metals to acid rai...

  5. Investigation of Pb, Cd, Cu and Mg Concentrations in Groundwater Resources of Razan Plain

    Directory of Open Access Journals (Sweden)

    S. Sobhan Ardakani

    2015-01-01

    Full Text Available Introduction & Objective: Iran is located in the dry and semi dry regions, thus almost 90% of the required fresh water is exploited from groundwater resources. Due to the increasing pol-lution of water resources, the purpose of this study was evaluation of Pb, Cd, Cu and Mg concentrations in groundwater resources of Razan Plain and preparing the zoning map using GIS. Materials & Methods: Groundwater samples were collected from 20 selected stations during two seasons in 2012. The samples were filtered (0.45 ?m and maintained cool in polyethyl-ene bottles. The samples were taken for the analysis of cations, the former was acidified with HNO3 to pH lower than 2. Minor elements were determined using ICP-OES. All statistical analyses were performed using the SPSS statistical package. Also, Kriging Method was used to prepare spatial distribution maps of elements in groundwater samples. Results: The results showed that the mean concentrations of Pb, Cd, Cu and Mg in the groundwater samples during the spring were 5.60±0.66, 0.21±0.04, 32.10±2.21 and 6990.0±302.10 ppb, respectively, and the mean concentrations of these elements in the groundwater samples in the summer were 4.86±0.46, 0.30±0.08, 25.55±3.63 and 3654.05±215.65 ppb, respectively. Comparing the mean concentrations of the evaluated metals with WHO permissible limits showed a significant difference (p<0.05. Thus, the mean concentrations of the metals were significantly lower than the permissible limits. Conclusion: Although the groundwater resources of Razan Plain are not currently polluted with heavy metals, long-term excessive use of agricultural inputs and establishment of pollut-ing industries, can pose a threat to groundwater resources of this area. (Sci J Hamadan Univ Med Sci 2015; 21(4:319-329

  6. Application of residual sludge: effects on soil nitrogen and retention of Cd, Cr, Hg and Zn by ray grass

    International Nuclear Information System (INIS)

    In pot studies on the application of urban sewage rich in organic matter as fertilizer (residual sludges from sewage purification stations), an investigation was made of the yield in dry matter and retention of Zn, Cd, Cr and Hg by ray grass, followed by an examination of the mineralization and organization of soil nitrogen or added nitrogen fertilizers. All the experiments described were conducted with tracers - radioactive in the case of Hg, Cd, Cr and Zn, and stable in the case of nitrogen. The main results obtained after six months' cultivation can be summarized as follows: (1) the suppressing effect produced immediately after application of a lime-treated sludge falls off rapidly (2-3 months), whereas the effect produced by straw persists even after six months. The sludges subsequently exert a positive effect on the yield of dry matter; (2) in the plant the transfer of the trace elements studied is not altered by adding residual sludges whereas the addition of 30 ppm of these elements to the soil in ionic form increases the plant content; (3) although the incorporation of straw into the soil considerably increases the organization of the nitrogen in the fertilizer applied, the changes are limited in the case of other forms of treatment. (author)

  7. Effect of hydrostatic pressure on the exchange interactions in a ferromagnetic spinel CdCr2Se4

    International Nuclear Information System (INIS)

    We have used electron paramagnetic resonance at hydrostatic pressures up to 8 GPa to study the pressure dependence of the nearest-neighbor and more-distant-neighbor exchange constants, J and K, in single-crystal samples of the ferromagnetic spinel CdCr2Se4. K is initially antiferromagnetic but changes sign near 5 GPa and increases rapidly at higher pressure. J remains ferromagnetic but decreases rapidly with pressure until at 8 GPA the total exchange contribution of the near neighbors becomes comparable to that of more-distant neighbors. We find that the lattice-constant dependence of J and K is much stronger than in the mixed-composition system CdCr2(Se/sub 1-x/S/sub x/)4 studied by Wojtowicz, Baltzer, and Robbins. The pressure dependence of the EPR linewidth above T/sub c/ is found to scale with the reduced temperature (T-T/sub c/)/T/sub c/ but with a change in slope at high temperatures that we attribute to changes in the phonon spectrum

  8. Solar-energy conversion by combined photovoltaic converters with CdTe and CuInSe2 base layers

    International Nuclear Information System (INIS)

    The possibility of the combined use of bifacial thin-film solar cells based on CdTe and frontal solar cells with a CuInSe2 base layer in tandem structures is experimentally confirmed. It is found that, for the use of bifacial solar cells based on cadmium telluride in a tandem structure, the optimal thickness of their base layer should be 1 μm. The gain in the efficiency of the tandem structure, compared with an individual CuInSe2-based solar cell, is 1.8% in the case of series-connected solar cells and 1.3%, for parallel-connected

  9. Particulate contacts to Si and CdTe: Al, Ag, Hg-Cu-Te, and Sb-Te

    Science.gov (United States)

    Schulz, Douglas L.; Ribelin, Rosine; Curtis, Calvin J.; Ginley, David S.

    1999-03-01

    Our team has been investigating the use of particle-based contacts in both Si and CdTe solar cell technologies. First, in the area of contacts to Si, powders of Al and Ag prepared by an electroexplosion process have been characterized by transmission electron microscopy (TEM), TEM elemental determination X-ray spectroscopy (TEM-EDS), and TEM electron diffraction (TEM-ED). These Al and Ag particles were slurried and tested as contacts to p- and n-type silicon wafers, respectively. Linear current-voltage (I-V) was observed for Ag on n-type Si, indicative of an ohmic contact, whereas the Al on p-type Si sample was non-ideal. A wet-chemical surface treatment was performed on one Al sample and TEM-EDS indicated a substantial decrease in the O contaminant level. The treated Al on p-type Si films exhibited linear I-V after annealing. Second, in the area of contacts to CdTe, particles of Hg-Cu-Te and Sb-Te have been applied as contacts to CdTe/CdS/SnO2 heterostructures prepared by the standard NREL protocol. First, Hg-Cu-Te and Sb-Te were prepared by a metathesis reaction. After CdCl2 treatment and NP etch of the CdTe layer, particle contacts were applied. The Hg-Cu-Te contacted cells exhibited good electrical characteristics, with Voc>810 mV and efficiencies > 11.5% for most cells. Although Voc>800 mV were observed for the Sb-Te contacted cells, efficiencies in these devices were limited to 9.1% presumably by a large series resistance (>20 Ω) observed in all samples.

  10. Development of high strength and high corrosion resistance 23Cr-18Ni-3Cu-1.5W steel tubes for boilers; Boiler yo kokyodo kotaishoku 23Cr-18Ni-3Cu-1.5W kokan no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Senba, H.; Sawaragi, Y.; Yamadera, Y.; Igarashi, M. [Sumitomo Metal Industries, Ltd., Osaka (Japan)

    1998-06-15

    An austenitic steel 23Cr-18Ni-3Cu-1.5W-0.4Nb-0.2N tube (SAVE25) is developed, high in strength and corrosion resistance, intended for use singly under the ultimate steam conditions (650degC and 350atm) for ultra supercritical power plants. This steel exhibits a high creep rupture strength, thanks to precipitation strengthened by a Cu-rich phase and carbon nitrides and to solid solution strengthened by texture-stabilizing W and N, and exhibits an estimated rupture strength of 91MPa after 10{sup 5}h at 700degC, equivalent to that of the high-Ni, high-W alloy HR6W (23Cr-43Ni-6W-Ti, Nb). Furthermore, its steam oxidation resistance and high-temperature corrosion resistance are so high as to be comparable to those of the HR3C (25Cr-20Ni-0.4Nb-0.25N). As for weldability, the SAVE25 is equal or superior to the TP347H which is widely used for boilers. New welding consumables are also under development, using the same alloy as the parent alloy, which produce welded joints which are equal to the parent alloy in terms of strength and corrosion resistance. This steel tube is already installed on service boilers for performance evaluation, and it is believed that the new steel tube will greatly contribute to the embodiment of ultra supercritical power plants. 11 refs., 19 figs., 2 tabs.

  11. Effects of CdS Buffer Layers on Photoluminescence Properties of Cu2ZnSnS4 Solar Cells

    OpenAIRE

    Le Donne, A.; Marchionna, S.; Garattini, P.; R. A. Mereu; Acciarri, M.; Binetti, S.

    2015-01-01

    Cu2ZnSnS4 (CZTS) absorber layers grown by sputtering were investigated by photoluminescence before and after the chemical bath deposition of CdS in order to evaluate the possible passivation of point defects by Cd atoms at the absorber/buffer layer interface. According to the literature, a broad emission around 1.21 eV was observed at low temperature under above bandgap excitation of the as-grown CZTS samples. Broad bands at 1.075 eV and 0.85 eV were detected for the first time under below ba...

  12. Equilibrium phase of high-entropy FeCoNiCrCu0.5 alloy at elevated temperature

    International Nuclear Information System (INIS)

    The phase transformations of FeCoNiCrCu0.5 alloy with the as-cast structure and heat-treated structures were studied. The as-cast alloy specimens were first heated at 1050 oC with a holding time of 1 h. Serial heat-treatment processes at 350 oC, 500 oC, 650 oC, 800 oC, 950 oC, 1100 oC, 1250 oC and 1350 oC 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 oC. The hardness of the FeCoNiCrCu0.5 alloy remained unchanged in the specimens that underwent various heat treatments that were applied in this study.

  13. Study of Magnetic Entropy Changes in Gd1-x Tx ( T = Ti, Cr, Fe and Cu) Alloys

    Institute of Scientific and Technical Information of China (English)

    Wang Dunhui; Huang Songling; Han Zhida; Zhang Jianrong; Du Youwei

    2004-01-01

    Magnetic refrigeration techniques based on the magnetocaloric effect (MCE) were demonstrated as a promising alternative to conventional vapour-cycle refrigeration.Recently, scientists focused their research on room temperature magnetic refrigeration.The rare earth Gd metal is regarded as a prototype for room temperature magnetic refrigerant.Considering the various requirements in application, it is necessary to search for the magnetic refrigerant possessing qualities as good as Gd but having different Tc above or below room temperature.In this article, we report the magnetic entropy changes in Gd1 -xTx(T = Ti, Cr, Fe and Cu) alloys.With a small quantity of T atoms introduced in Gd, the Curie temperature increases.The values of magnetic entropy change in these alloys are almost the same as or a little less than that of Gd.But the refrigerant capacities of these alloys are obviously larger than that of Gd.All these facts suggest that Gd1-xTx(T = Ti, Cr, Fe and Cu) alloys may be good refrigerants for room temperature magnetic refrigeration.

  14. Exchange coupling and helical spin order in the triangular lattice antiferromagnet CuCrO2 using first principles

    Institute of Scientific and Technical Information of China (English)

    Jiang Xue-Fan; Liu Xian-Feng; Wu Yin-Zhong; Han Jiu-Rong

    2012-01-01

    The magnetic and electronic properties of the geometrically frustrated triangular antiferromagnet CuCrO2 are investigated by first principles through density functional theory calculations within the generalized gradient approximations (GGA)+U scheme.The spin exchange interactions up to the third nearest neighbours in the ab plane as well as the coupling between adjacent layers are calculated to examine the magnetism and spin frustration.It is found that CuCrO2 has a natural two-dimensional characteristic of the magnetic interaction.Using Monte-Carlo simulation,we obtain the Néel temperature to be 29.9 K,which accords well with the experimental value of 24 K.Based on noncollinear magnetic structure calculations,we verify that the incommensurate spiral-spin structure with (110) spiral plane is believable for the magnetic ground state,which is consistent with the experimental observations.Due to intra-layer geometric spin frustration,parallel helical-spin chains arise along the a,b,or a + b directions,each with a screw-rotation angle of about 120°.Our calculations of the density of states show that the spin frustration plays an important role in the change of d-p hybridization,while the spin-orbit coupling has a very limited influence on the electronic structure.

  15. Development of a low temperature solid HIP process for joining CFC monoblocks onto CuCrZr tubes

    International Nuclear Information System (INIS)

    A low temperature solid HIP process is developed for ITER Divertor Baffle components in order to join AMC CFC monoblocks onto CuCrZr tubes without overaging. For the fabrication solution annealed cold worked CuCrZr-tubes age-hardened during the hot isostatic pressing (HIP) process are joined to the back-casted (AMC) WHC copper ring of the WC monoblock. The process relevant influence parameters (clearance between components, thickness of can, maximum HIP pressure, pressure and temperature history in time) and quality relevant parameters (contact pressure at HIP interface, stresses in the WC body) are determined in a brainstorming. By using the design of experiments (DoE) software a number of parameter sets are defined that act as input for the process simulation via finite element method (FEM) based models each of which representing an individual parameter set. The values for the quality relevant parameters calculated this way are then evaluated with the DoE software in order to detect the functional dependencies between them. An optimum set of parameters is detected and has been verified successfully in a manufacturing process of several prototype components as well as full-scale components for the ITER Divertor Baffle. (author)

  16. Structure formation and properties of sputter deposited Nbx-CoCrCuFeNi high entropy alloy thin films

    International Nuclear Information System (INIS)

    Thin films of the high entropy alloy Nbx-CoCrCuFeNi with different niobium concentrations were deposited by magnetron sputtering. The film density and the residual stress of the niobium-free (x = 0) thin films clearly decreases at higher pressure-distance products. This behaviour can only be explained by the momentum transfer of the sputtered atoms and the reflected Ar atoms on the growing film as the energy per arriving atom shows little variation. The addition of Nb, which is the heaviest atom of the alloy, amplifies this effect. Hence, thin films with a high Nb content still show a high density at large pressure-distance products. However, as Nb has the largest radius of all constituent elements, the crystallographic structure of the thin films changes from a crystalline face-centred cubic structure at x = 0 to an amorphous (or nanocrystalline) structure for higher Nb fractions. Both trends, i.e. the changing deposition conditions and the niobium content, can be outlined by a study of the thin film microstrain. The trends observed in the intrinsic properties are correlated to a preliminary study of some functional properties (friction coefficient, thermal stability and contact resistance). - Highlights: • Nbx-CoCrCuFeNi thin films were deposited by sputtering pressed powder targets. • The Nb fraction and deposition conditions influence the intrinsic film properties. • The functional film properties are explained by the momentum transfer concept

  17. Thermal cycling tests of 1st wall mock-ups with beryllium/CuCrZr bonding

    International Nuclear Information System (INIS)

    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/m2, 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)

  18. Tribological Properties of AlCrCuFeNi2 High-Entropy Alloy in Different Conditions

    Science.gov (United States)

    Liu, Yong; Ma, Shengguo; Gao, Michael C.; Zhang, Chuan; Zhang, Teng; Yang, Huijun; Wang, Zhihua; Qiao, Junwei

    2016-07-01

    In order to understand the environmental effect on the mechanical behavior of high-entropy alloys, the tribological properties of AlCrCuFeNi2 are studied systematically in dry, simulated rainwater, and deionized water conditions against the Si3N4 ceramic ball at a series of different normal loads. The present study shows that both the friction and wear rate in simulated rainwater are the lowest. The simulated rainwater plays a significant role in the tribological behavior with the effect of forming passive film, lubricating, cooling, cleaning, and corrosion. The wear mechanism in simulated rainwater is mainly adhesive wear accompanied by abrasive wear as well as corrosive wear. In contrast, those in dry condition and deionized water are abrasive wear, adhesive wear, and surface plastic deformation. Oxidation contributes to the wear behavior in dry condition but is prevented in liquid condition. In addition, the phase diagram of Al x CrCuFeNi2 is predicted using CALPHAD modeling, which is in good agreement with the literature report and the present study.

  19. Tribological Properties of AlCrCuFeNi2 High-Entropy Alloy in Different Conditions

    Science.gov (United States)

    Liu, Yong; Ma, Shengguo; Gao, Michael C.; Zhang, Chuan; Zhang, Teng; Yang, Huijun; Wang, Zhihua; Qiao, Junwei

    2016-02-01

    In order to understand the environmental effect on the mechanical behavior of high-entropy alloys, the tribological properties of AlCrCuFeNi2 are studied systematically in dry, simulated rainwater, and deionized water conditions against the Si3N4 ceramic ball at a series of different normal loads. The present study shows that both the friction and wear rate in simulated rainwater are the lowest. The simulated rainwater plays a significant role in the tribological behavior with the effect of forming passive film, lubricating, cooling, cleaning, and corrosion. The wear mechanism in simulated rainwater is mainly adhesive wear accompanied by abrasive wear as well as corrosive wear. In contrast, those in dry condition and deionized water are abrasive wear, adhesive wear, and surface plastic deformation. Oxidation contributes to the wear behavior in dry condition but is prevented in liquid condition. In addition, the phase diagram of Al x CrCuFeNi2 is predicted using CALPHAD modeling, which is in good agreement with the literature report and the present study.

  20. 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.