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Sample records for iron surface determinant

  1. Iron oxide surfaces

    Science.gov (United States)

    Parkinson, Gareth S.

    2016-03-01

    known with a high degree of precision and the major defects and properties are well characterised. A major factor in this is that a termination at the Feoct-O plane can be reproducibly prepared by a variety of methods, as long as the surface is annealed in 10-7-10-5 mbar O2 in the final stage of preparation. Such straightforward preparation of a monophase termination is generally not the case for iron oxide surfaces. All available evidence suggests the oft-studied (√2×√2)R45° reconstruction results from a rearrangement of the cation lattice in the outermost unit cell in which two octahedral cations are replaced by one tetrahedral interstitial, a motif conceptually similar to well-known Koch-Cohen defects in Fe1-xO. The cation deficiency results in Fe11O16 stoichiometry, which is in line with the chemical potential in ultra-high vacuum (UHV), which is close to the border between the Fe3O4 and Fe2O3 phases. The Fe3O4(111) surface is also much studied, but two different surface terminations exist close in energy and can coexist, which makes sample preparation and data interpretation somewhat tricky. Both the Fe3O4(100) and Fe3O4(111) surfaces exhibit Fe-rich terminations as the sample selvedge becomes reduced. The Fe3O4(110) surface forms a one-dimensional (1×3) reconstruction linked to nanofaceting, which exposes the more stable Fe3O4(111) surface. α-Fe2O3(0001) is the most studied haematite surface, but difficulties preparing stoichiometric surfaces under UHV conditions have hampered a definitive determination of the structure. There is evidence for at least three terminations: a bulk-like termination at the oxygen plane, a termination with half of the cation layer, and a termination with ferryl groups. When the surface is reduced the so-called "bi-phase" structure is formed, which eventually transforms to a Fe3O4(111)-like termination. The structure of the bi-phase surface is controversial; a largely accepted model of coexisting Fe1-xO and α-Fe2O3(0001) islands

  2. Determination of enthalpy, temperature, surface tension and geometry of the material transfer in PGMAW for the system argon–iron

    International Nuclear Information System (INIS)

    Siewert, E; Schein, J; Forster, G

    2013-01-01

    The metal transfer is a fundamental process in gas metal arc welding, which substantially determines the shape of the weld seam and strongly influences arc formation and stability. In this investigation the material transfer from the wire electrode (anode) to the workpiece (cathode) is analysed experimentally with high accuracy using various innovative diagnostic techniques for a pulsed gas metal arc welding (PGMAW) process. A high-speed two-colour pyrometer, a calorimeter, thermocouples, a stereo optical setup and a droplet oscillation technique are used to analyse a precisely defined PGMAW process. Thus, results obtained are verified by different measurement techniques and enable a comprehensive description of the material transfer procedure. The surface temperature of both electrodes as well as the droplet temperature, enthalpy and surface tension were determined. Furthermore, the geometry of the arc, wire, droplets and weld pool were extracted in three dimensions in order to describe the interaction between the material transfer and the formation of the weld seam. The experiments are performed using argon as shielding gas and pure iron as filler and base material to reduce complex chemical processes. It turned out that the wire feed rate has the biggest influence on droplet temperature and detachment. A correlation between weld pool formation and weld pool surface temperature gradient was observed, which is mainly a function of welding speed and wire feed rate. The experimental results obtained provide a detailed data pool for use in modelling. (paper)

  3. Determinants of compliance to iron supplementation among ...

    African Journals Online (AJOL)

    2014-01-28

    Jan 28, 2014 ... practice of routine iron supplementation in pregnancy. The major problem with .... elemental iron and 350 μg of folic acid per tablet. Definition of ..... Determinants of adherence to iron/folate supplementation during pregnancy.

  4. Iron cycling at corroding carbon steel surfaces

    Science.gov (United States)

    Lee, Jason S.; McBeth, Joyce M.; Ray, Richard I.; Little, Brenda J.; Emerson, David

    2013-01-01

    Surfaces of carbon steel (CS) exposed to mixed cultures of iron-oxidizing bacteria (FeOB) and dissimilatory iron-reducing bacteria (FeRB) in seawater media under aerobic conditions were rougher than surfaces of CS exposed to pure cultures of either type of microorganism. The roughened surface, demonstrated by profilometry, is an indication of loss of metal from the surface. In the presence of CS, aerobically grown FeOB produced tight, twisted helical stalks encrusted with iron oxides. When CS was exposed anaerobically in the presence of FeRB, some surface oxides were removed. However, when the same FeOB and FeRB were grown together in an aerobic medium, FeOB stalks were less encrusted with iron oxides and appeared less tightly coiled. These observations suggest that iron oxides on the stalks were reduced and solubilized by the FeRB. Roughened surfaces of CS and denuded stalks were replicated with three culture combinations of different species of FeOB and FeRB under three experimental conditions. Measurements of electrochemical polarization resistance established different rates of corrosion of CS in aerobic and anaerobic media, but could not differentiate rate differences between sterile controls and inoculated exposures for a given bulk concentration of dissolved oxygen. Similarly, total iron in the electrolyte could not be used to differentiate treatments. The experiments demonstrate the potential for iron cycling (oxidation and reduction) on corroding CS in aerobic seawater media. PMID:24093730

  5. Electron Spectroscopy Studies of Iron, Iron Sulfides and Supported Iron Surfaces: Chemisorption of Simple Gases.

    Science.gov (United States)

    Lee, Yiu Chung

    EELS was used to investigate the chemisorption of oxygen and carbon on iron. The EELS spectra of oxidized iron show characteristic features with strong enhancement of the interband transitions involving the Fe 3d band (4.6 and 7.5 eV) and moderate enhancement of the M(,2,3) transition doublet (54.4 and 58.2 eV). The changes in the electron energy loss structures with an overlayer of graphitic or carbidic carbon were investigated. The adsorption and growth of iron on Ni(100) has been studied using the combined techniques of LEED and EELS. Initially iron grows by a layer-by-layer mechanism for the first few layers. High iron coverages result in the observation of complex LEED patterns with satellites around the main (1 x 1) diffraction sports. This is due to the formation of b.c.c. Fe(110) crystallites arranged in domains with different orientations. EELS studies show the presence of three stages in the growth of iron on Ni(100): low-coverage, film-like and bulk-like. Auger and EELS were used to study the iron sulfide (FeS(,2), Fe(,7)S(,8) and FeS) surfaces. A characteristic M(,2,3) VV Auger doublet with a separation of 5.0 eV was observed on the sulfides. An assignment of the electron energy loss peaks was made based on the energy dependence of the loss peaks and previous photoemission results. The effect of argon ion bombardment was studied. Peaks with strong iron and sulfur character were observed. Heating the damaged sulfides results in reconstruction of the sulfide surfaces. The reactions of the sulfides with simple gases, such as H(,2), CO, CH(,4), C(,2)H(,4), NH(,3) and O(,2) were also studied. Using XPS, the chemisorption of SO(,2) on CaO(100) has been studied. The chemical state of sulfur has been identified as that of sulfate. The kinetics of SO(,2) chemisorption on CaO are discussed. The binding states of Fe and Na on CaO were determined to be Fe('2+) and Na('+) respectively. At low Fe or Na coverages (< 0.5 ML), there is a large increase in the rate of

  6. Rate and extent of aqueous perchlorate removal by iron surfaces.

    Science.gov (United States)

    Moore, Angela M; De Leon, Corinne H; Young, Thomas M

    2003-07-15

    The rate and extent of perchlorate reduction on several types of iron metal was studied in batch and column reactors. Mass balances performed on the batch experiments indicate that perchlorate is initially sorbed to the iron surface, followed by a reduction to chloride. Perchlorate removal was proportional to the iron dosage in the batch reactors, with up to 66% removal in 336 h in the highest dosage system (1.25 g mL(-1)). Surface-normalized reaction rates among three commercial sources of iron filings were similar for acid-washed samples. The most significant perchlorate removal occurred in solutions with slightly acidic or near-neutral initial pH values. Surface mediation of the reaction is supported by the absence of reduction in batch experiments with soluble Fe2+ and also by the similarity in specific reaction rate constants (kSA) determined for three different iron types. Elevated soluble chloride concentrations significantly inhibited perchlorate reduction, and lower removal rates were observed for iron samples with higher amounts of background chloride contamination. Perchlorate reduction was not observed on electrolytic sources of iron or on a mixed-phase oxide (Fe3O4), suggesting that the reactive iron phase is neither pure zerovalent iron nor the mixed oxide alone. A mixed valence iron hydr(oxide) coating or a sorbed Fe2+ surface complex represent the most likely sites for the reaction. The observed reaction rates are too slow for immediate use in remediation system design, but the findings may provide a basis for future development of cost-effective abiotic perchlorate removal techniques.

  7. Surface effects in metallic iron nanoparticles

    DEFF Research Database (Denmark)

    Bødker, Franz; Mørup, Steen; Linderoth, Søren

    1994-01-01

    Nanoparticles of metallic iron on carbon supports have been studied in situ by use of Mossbauer spectroscopy. The magnetic anisotropy energy constant increases with decreasing particle size, presumably because of the influence of surface anisotropy. Chemisorption of oxygen results in formation...

  8. Determination of metallic iron in sponge-iron

    International Nuclear Information System (INIS)

    Mueller, C.S.

    1974-01-01

    The amount of metallic iron in sponge-iron is a parameter of major interest in the evaluation of the performance of the ore-reduction process and in the determination of the composition of the load of the electric furnace used to produce the steel. Moessbauer effect offers the promise of a simple and elegant analysis method, capable of competing directly with the usually time-consuming chemical procedures. The applicability of the method is considered and the possible sources of error are analyzed, resulting in the design of an instrument that is reasonably accurate and simple to use. Detailed electronic circuity required to produce a direct-reading digital instrument is shown [pt

  9. Characterization of the mechanism of protection mediated by CS-D7, a monoclonal antibody to Staphylococcus aureus iron regulated surface determinant B (IsdB

    Directory of Open Access Journals (Sweden)

    Gregory ePancari

    2012-03-01

    Full Text Available We previously reported the development of a human monoclonal antibody (CS-D7, IgG1 with specificity and affinity for the iron regulated surface determinant B (IsdB of Staphylococcus aureus. CS-D7 mediates opsonophagocytic killing in vitro and protection in a murine sepsis model. In light of recent data indicating that IsdB specific T cells (CD4+, Th17, not Ab, mediate protection after vaccination with IsdB, it is important to investigate the mechanism of protection mediated by CS-D7. The mAb was examined to determine if it blocked heme binding to IsdB in vitro. The mAb was not found to have heme blocking activity, nor did it prevent bacterial growth under in vivo conditions, in an implanted growth chamber. To assess the role of the mAb Fc a point mutation was introduced at aa 297 (CS-D7●N297A. This point mutation removes Fc effector functions. In vitro analysis of the mutein confirmed that it lacked measurable binding to FcγR, and that it did not fix complement. The mutein had dramatically reduced in vitro opsonic OP activity compared to CS-D7. Nonetheless, the mutein conferred protection equivalent to the wild type mAb in the murine sepsis model. Both wild type and mutein mAbs were efficacious in FcγR deletion mice (including both FcγRII-/- mice and FcγRIII-/- mice, indicating that these receptors were not essential for mAb mediated protection in vivo. Protection mediated by CS-D7 was lost in Balb/c mice depleted of C3 with cobra venom factor (CFV, was lost in mice depleted of superoxide dismutase (SOD in P47phox deletion mice, and was absent in SCID mice. Enhanced clearance of S. aureus in the liver of CS-D7 treated mice and enhanced production of INF-γ, but not of IL17, may play a role in the mechanism of protection mediated by the mAb. CS-D7 apparently mediates survival in challenged mice through a mechanism involving complement, phagocytes, and lymphocytes, but which does not depend on interaction with FcγR, or on blocking heme

  10. Adsorption energy of iron-phthalocyanine on crystal surfaces

    International Nuclear Information System (INIS)

    Struzzi, C.; Scardamaglia, M.; Angelucci, M; Massimi, L.; Mariani, C.; Betti, G.

    2013-01-01

    The adsorption energy of iron-phthalocyanine (FePc) deposited on different crystal surfaces is studied by thermal desorption spectroscopy. A thin film of molecules has been absorbed on highly oriented pyrolytic graphite (HOPG), on graphene epitaxially grown on Ir(111), and on Au(110). Activation energies for the desorption of a molecular thin film and for the FePc single layer are determined at the three surfaces. The desorption temperature measured for the thin films is only slightly dependent on the substrate, since it is mostly dominated by molecule-molecule interactions. A definitely different desorption temperature is found at the single-layer coverage: we find an increasing desorption temperature going from HOPG, to graphene/Ir, to the Au(110) surface. The different adsorption energies of the first FePc layer in contact with the substrate surface are discussed taking into account the interaction and the growth morphology.

  11. Bioavailability of elemental iron powders to rats is less than bakery-grade ferrous sulfate and predicted by iron solubility and particle surface area.

    Science.gov (United States)

    Swain, James H; Newman, Samuel M; Hunt, Janet R

    2003-11-01

    Foods are fortified with elemental forms of iron to reduce iron deficiency. However, the nutritional efficacy of current, commercially produced elemental iron powders has not been verified. We determined the bioavailability of six commercial elemental iron powders and examined how physicochemistry influences bioavailability. Relative biological value (RBV) of the iron powders was determined using a hemoglobin repletion/slope ratio method, treating iron-deficient rats with repletion diets fortified with graded quantities of iron powders, bakery-grade ferrous sulfate or no added iron. Iron powders were assessed physicochemically by measuring iron solubility in hydrochloric acid at pH 1.0 and 1.7, surface area by nitrogen gas adsorption and surface microstructure by electron microscopy. Bioavailability from the iron powders, based on absolute iron intake, was significantly less than from FeSO4 (100%; P Electrolytic (54%; A-131, U.S.) > Electrolytic (46%; Electrolytic Iron, India) > H-Reduced (42%; AC-325, U.S.) > Reduced (24%; ATOMET 95SP, Canada) > CO-Reduced (21%; RSI-325, Sweden). Solubility testing of the iron powders resulted in different relative rankings and better RBV predictability with increasing time at pH 1.7 (R2 = 0.65 at 150 min). The prediction was improved with less time and lower pH (R2 = 0.82, pH 1.0 at 30 min). Surface area, ranging from 90 to 370 m2/kg, was also highly predictive of RBV (R2 = 0.80). Bioavailability of iron powders is less than bakery-grade ferrous sulfate and varies up to three times among different commercial forms. Solubility at pH 1.0 and surface area were predictive of iron bioavailability in rats.

  12. Laser surface treatment of grey cast iron for automotive applications

    NARCIS (Netherlands)

    Ocelik, V.; Tang, P.N.; de Boer, M.C.; de Oliveira, U.; de Hosson, J.T.M.; DeHosson, JTM; Brebbia, CA; Nishida, SI

    2005-01-01

    The surface of pearlitic grey cast iron was treated using a 2 kW Nd:YAG laser beam with the final aim to improve its surface properties, mainly for automotive applications. Two kinds of laser surface treatments were experimentally applied. In the laser surface hardening approach the surface of cast

  13. Iron status determination in pregnancy using the Thomas plot.

    Science.gov (United States)

    Weyers, R; Coetzee, M J; Nel, M

    2016-04-01

    Physiological changes during pregnancy affect routine tests for iron deficiency. The reticulocyte haemoglobin equivalent (RET-He) and serum-soluble transferrin receptor (sTfR) assay are newer diagnostic parameters for the detection of iron deficiency, combined in the Thomas diagnostic plot. We used this plot to determine the iron status of pregnant women presenting for their first visit to an antenatal clinic in Bloemfontein, South Africa. Routine laboratory tests (serum ferritin, full blood count and C-reactive protein) and RET-He and sTfR were performed. The iron status was determined using the Thomas plot. For this study, 103 pregnant women were recruited. According to the Thomas plot, 72.8% of the participants had normal iron stores and erythropoiesis. Iron-deficient erythropoiesis was detected in 12.6%. A third of participants were anaemic. Serum ferritin showed excellent sensitivity but poor specificity for detecting depleted iron stores. HIV status had no influence on the iron status of the participants. Our findings reiterate that causes other than iron deficiency should be considered in anaemic individuals. When compared with the Thomas plot, a low serum ferritin is a sensitive but nonspecific indicator of iron deficiency. The Thomas plot may provide useful information to identify pregnant individuals in whom haematologic parameters indicate limited iron availability for erythropoiesis. © 2015 John Wiley & Sons Ltd.

  14. Determining Iron Content in Foods by Spectrophotometry.

    Science.gov (United States)

    Adams, Paul E.

    1995-01-01

    Describes a laboratory experiment for secondary school chemistry students utilizing the classic reaction between the iron(III) ion and the thiocyanate ion. The experiment also works very well in other chemistry courses as an experience in spectrophotometric analysis. (PVD)

  15. Determination of Iron Content in Iron Deficiency Drugs by UV-Visible Spectrophotometer

    Directory of Open Access Journals (Sweden)

    Isam Eldin Hussein Elgailani

    2017-07-01

    Full Text Available The objective of this work was to validate a simple, precise and accurate spectrophotometric method for the determination of iron in the iron deficiency drugs, namely are Feroglobin B12, Ferose-F and Ferose. The proposed method is based on the reaction of iron with ammonium thiocyanate after the wet digestion of the drugs under study with HNO3 and H2O2.  Effects of pH, temperature, standing time and thiocyanate concentration on the determination of iron in drugs containing iron have been investigated. The λmax was 430 nm and the molar absorptivity of 0.0399 L mol-1 cm-1. The linear regression was in the range 0.5 - 60 μg/mL for iron content in hemoglobin. The detection limit and the limit of quantification were found to be 0.040 and 0.122 µg mL-1 for the iron respectively, and with a linear regression correlation coefficient of 0.998. Recovery measurements ranged from 99.63-100.20%. This method is simple and fast can be used for the determination of iron in the iron deficiency drugs in pharmaceutical laboratories. DOI: http://dx.doi.org/10.17807/orbital.v9i3.953

  16. On surface reactions of iron tungstate with ethane

    International Nuclear Information System (INIS)

    Obrubov, V.A.; Shchukin, V.P.; Averbukh, A.Ya.

    1980-01-01

    Results of investigation of ethane oxidation reaction upon iron tungstate are presented. It is shown that catalytic oxidation of ethane is accompanied by the surface reaction of the catalyst reduction. Maximum reduction of surface depends upon temperature and considerably affects the direction of ethane oxidation process. Activation energies of ethane oxidation reactions and surface reaction of iron tungstate reduction depend on the surface actual state and at its reduction up to 5% from monolayer change in the limits 36.0-46.0 and 53.0-66.0 kcal/mol respectively

  17. Determinants of iron accumulation in the normal aging brain.

    Science.gov (United States)

    Pirpamer, Lukas; Hofer, Edith; Gesierich, Benno; De Guio, François; Freudenberger, Paul; Seiler, Stephan; Duering, Marco; Jouvent, Eric; Duchesnay, Edouard; Dichgans, Martin; Ropele, Stefan; Schmidt, Reinhold

    2016-07-01

    In a recent postmortem study, R2* relaxometry in gray matter (GM) of the brain has been validated as a noninvasive measure for iron content in brain tissue. Iron accumulation in the normal aging brain is a common finding and relates to brain maturation and degeneration. The goal of this study was to assess the determinants of iron accumulation during brain aging. The study cohort consisted of 314 healthy community-dwelling participants of the Austrian Stroke Prevention Study. Their age ranged from 38-82 years. Quantitative magnetic resonance imaging was performed on 3T and included R2* mapping, based on a 3D multi-echo gradient echo sequence. The median of R2* values was measured in all GM regions, which were segmented automatically using FreeSurfer. We investigated 25 possible determinants for cerebral iron deposition. These included demographics, brain volume, lifestyle factors, cerebrovascular risk factors, serum levels of iron, and single nucleotide polymorphisms related to iron regulating genes (rs1800562, rs3811647, rs1799945, and rs1049296). The body mass index (BMI) was significantly related to R2* in 15/32 analyzed brain regions with the strongest correlations found in the amygdala (p = 0.0091), medial temporal lobe (p = 0.0002), and hippocampus (p ≤ 0.0001). Further associations to R2* values were found in deep GM for age and smoking. No significant associations were found for gender, GM volume, serum levels of iron, or iron-associated genetic polymorphisms. In conclusion, besides age, the BMI and smoking are the only significant determinants of brain iron accumulation in normally aging subjects. Smoking relates to iron deposition in the basal ganglia, whereas higher BMI is associated with iron content in the neocortex following an Alzheimer-like distribution. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Assessment of iron deficiency in pregnant women by determining iron status

    International Nuclear Information System (INIS)

    Raza, N.; Munazza, B.; Ayub, M.; Sarwar, I

    2011-01-01

    Background: Pregnant women constitute a high risk group for iron deficiency. Maternal iron deficiency and particularly iron deficiency anaemia may be associated with detrimental effects on maternal and infant function and particularly with a higher risk of preterm delivery and delivery of low birth weight neonates. Objective of this study was to assess and compare the iron status of normal healthy non-pregnant women with that of pregnant women of Hazara Division. Methods: This study was conducted at Faculty of Health Sciences, Hazara University, and Ayub Medical College, Abbottabad from first March to /31 August 2006. Altogether 120 women, 90 pregnant at various stages of pregnancy and 30 non-pregnant women as control group were included in this study by convenience sampling. Their iron status was assessed by determination of haemoglobin (Hb), Serum ferritin, Serum-iron, Total Iron Binding Capacity (TIBC), Unsaturated Iron Binding Capacity (UIBC), and Percentage saturation of transferrin. Data generated on these variables were subjected to ANOVA and correlation analysis. Results: The salient finding of this study is a significant decrease in Hb, Serum ferritin, Serum iron, percentage saturation of transferrin and a significant increase in values of TIBC and a pronounced increase in UIBC in second and third trimester compared to first trimester in iron deficient pregnant women. The mean values of Hb, SF, and Fe/TIBC% were significantly lower in the cases than in the control and significantly higher values of TIBC and UIBC were observed in the cases compared to controls. Significant correlations were observed for TIBC, UIBC and Fe/TIBC% against serum iron in different trimesters of pregnancy. Conclusion: A high percentage of the pregnant women are iron deficient due to factors such as high parity, poor dietary habits and socioeconomic status. (author)

  19. Reductive precipitation of neptunium on iron surfaces under anaerobic conditions

    Science.gov (United States)

    Yang, H.; Cui, D.; Grolimund, D.; Rondinella, V. V.; Brütsch, R.; Amme, M.; Kutahyali, C.; Wiss, A. T.; Puranen, A.; Spahiu, K.

    2017-12-01

    Reductive precipitation of the radiotoxic nuclide 237Np from nuclear waste on the surface of iron canister material at simulated deep repository conditions was investigated. Pristine polished as well as pre-corroded iron specimens were interacted in a deoxygenated solution containing 10-100 μM Np(V), with 10 mM NaCl and 2 mM NaHCO3 as background electrolytes. The reactivity of each of the two different systems was investigated by analyzing the temporal evolution of the Np concentration in the reservoir. It was observed that pre-oxidized iron specimen with a 40 μm Fe3O4 corrosion layer are considerably more reactive regarding the reduction and immobilization of aqueous Np(V) as compared to pristine polished Fe(0) surfaces. 237Np immobilized by the reactive iron surfaces was characterized by scanning electron microscopy as well as synchrotron-based micro-X-ray fluorescence and X-ray absorption spectroscopy. At the end of experiments, a 5-8 μm thick Np-rich layer was observed to be formed ontop of the Fe3O4 corrosion layer on the iron specimen. The findings from this work are significant in the context of performance assessments of deep geologic repositories using iron as high level radioactive waste (HLW) canister material and are of relevance regarding removing pollutants from contaminated soil or groundwater aquifer systems.

  20. The determination of iron-59 in water

    International Nuclear Information System (INIS)

    Zhao Min; Ban Ying

    1993-06-01

    A method to analyse iron-59 in water is introduced. The procedure of this method includes concentration by co-precipitation with hydroxides purification by anion exchange, electrodeposition in NH 4 H 2 PO 4 -(NH 4 ) 2 CO 3 system and final measurements of beta activity with a background beta-counter. The effect of iron carrier amount and pH value of water sample on the carrying Fe-59, and the effect of concentration hydrochloric acid, flowrate of adsorption and elutriation with 6 mol/L HCl-1% H 2 O 2 solution on the adsorption efficiency have been studied. The experimental results indicate that for 101 water sample, both the chemical and radiochemical yields are greater than 90%. For 51 Cr, 60 Co, 65 Zn, 95 Zr- 95 Nb and 137 Cs the decontamination factor is greater than 10 3 . The minimum detectable limit of this method is 3.8 x 10 -3 Bq/L

  1. The separation and determination of trace elements in iron ore

    International Nuclear Information System (INIS)

    Jones, E.A.

    1977-01-01

    The separation, concentration, and determination of trace elements in iron ores are described. After the sample has been dissolved, the iron is separated by liquid-liquid extraction with a liquid cation-exchanger, di-(2-ethylhexyl) phosphoric acid. The trace elements aluminium, cadmium, calcium, chromium, cobalt, copper, lead, magnesium, manganese, mercury, potassium, sodium, vanadium, and zinc are determined in the aqueous phase by atomic-absorption spectrophotometry

  2. SURFACE CAST IRON STRENGTHENING USING COMBINED LASER AND ULTRASONIC PROCESSING

    Directory of Open Access Journals (Sweden)

    O. G. Devojno

    2013-01-01

    Full Text Available The paper provides an analysis of ultrasonic surface plastic deformation and subsequent laser thermal strengthening of gray cast iron parts in the regime of hardening from a solid state with the purpose to obtain strengthened surface layers of bigger depth and less roughness of the processed surface. Program complex ANSYS 11.0 has been used for calculation of temperature fields induced by laser exposure.  The appropriate regime of laser processing without surface fusion has been selected on the basis of the applied complex. The possibility of displacement in the bottom boundary of α–γ-transformation temperature  for СЧ20 with 900 °С up to 800 °С is confirmed due to preliminary ultrasonic surface plastic deformation of the surface that allows to expand technological opportunities of laser quenching  of gray  cast iron from a solid state. 

  3. Surface hardening of two cast irons by friction stir processing

    International Nuclear Information System (INIS)

    Fujii, Hidetoshi; Kikuchi, Toshifumi; Nogi, Kiyoshi; Yamaguchi, Yasufumi; Kiguchi, Shoji

    2009-01-01

    The Friction Stir Processing (FSP) was applied to the surface hardening of cast irons. Flake graphite cast iron (FC300) and nodular graphite cast iron (FCD700) were used to investigate the validity of this method. The matrices of the FC300 and FC700 cast irons are pearlite. The rotary tool is a 25mm diameter cylindrical tool, and the travelling speed was varied between 50 and 150mm/min in order to control the heat input at the constant rotation speed of 900rpm. As a result, it has been clarified that a Vickers hardness of about 700HV is obtained for both cast irons. It is considered that a very fine martensite structure is formed because the FSP generates the heat very locally, and a very high cooling rate is constantly obtained. When a tool without an umbo (probe) is used, the domain in which graphite is crushed and striated is minimized. This leads to obtaining a much harder sample. The hardness change depends on the size of the martensite, which can be controlled by the process conditions, such as the tool traveling speed and the load. Based on these results, it was clarified that the FSP has many advantages for cast irons, such as a higher hardness and lower distortion. As a result, no post surface heat treatment and no post machining are required to obtain the required hardness, while these processes are generally required when using the traditional methods.

  4. Surface energy of amorphous carbon films containing iron

    International Nuclear Information System (INIS)

    Chen, J. S.; Lau, S. P.; Tay, B. K.; Chen, G. Y.; Sun, Z.; Tan, Y. Y.; Tan, G.; Chai, J. W.

    2001-01-01

    Iron containing diamond-like amorphous carbon (a-C:Fe) films were deposited by filtered cathodic vacuum arc technique. The influences of Fe content and substrate bias on the surface energy of the films were investigated. The surface energy of a-C:Fe films was determined by the contact angle measurement. Atomic force microscopy, Raman spectroscopy, and x-ray induced photoelectron spectroscopy were employed to analyze the origin of the variation of surface energy with various Fe content and substrate bias. It is found that the contact angle for water increases significantly after incorporating Fe into the films and the films become hydrophobic. The roughness of these films has no effect on the contact angle. The surface energy is reduced from 42.8 to 25 dyne/cm after incorporating Fe into the a-C film (10% Fe in the target), which is due to the reduction of both dispersive and polar component. The reduction in dispersive component is ascribed to the decrease of atomic density of the a-C:Fe films due to the increase in sp 2 bonded carbon. When sp 2 content increases to some extent, the atomic density remains constant and hence dispersive component does not change. The absorption of oxygen on the surface plays an important role in the reduction of the polar component for the a-C:Fe films. It is proposed that such network as (C n - O - Fe) - O - (Fe - O - C n ) may be formed and responsible for the reduction of polar component. [copyright] 2001 American Institute of Physics

  5. Determination of iron 55 in nuclear wastes and effluents

    International Nuclear Information System (INIS)

    Raymond, A.; Revy, D.

    1989-01-01

    The methods for iron 55 analysis, described in this report allows measurement in different types of radioactive wastes after a specific chemical separation. Detection limit is near 1 Bq/l and the concentration factor can reach 100. Activity level found show that iron 55 is a major activation product, then the chemical determination is indispensable for a complete inventory of radionuclides in radioactive wastes [fr

  6. The surface layer of austempered ductile iron investment castings properties

    Directory of Open Access Journals (Sweden)

    D. Myszka

    2009-01-01

    Full Text Available The article presents a unique process of carbonnitriding and nitriding the precision casting surfaces of austempered ductile iron. The results of the research are pointing that adequate process parameters allow to obtain multiple increase of wear resistance and a significant increase of corrosion resistance. Also, changes of cast microstructure and hardness are presented.

  7. Iron migration from the anode surface in alumina electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhuravleva, Elena N.; Drozdova, Tatiana N.; Ponomareva, Svetlana V. [Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Kirik, Sergei D., E-mail: kiriksd@yandex.ru [Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Institute of Chemistry and Chemical Technology SB RAS, Krasnoyarsk, 660036 (Russian Federation)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Corrosion destruction of two-component iron-based alloys in high-temperature aluminum electrolysis in the cryolite alumina melt has been studied. Black-Right-Pointing-Pointer It was found that at the first stage oxidative polarization of iron atoms on the anode surface into Fe{sup 2+} takes place. Black-Right-Pointing-Pointer Fe{sup 2+} interacts with cryolite melt producing FeF{sub 2}. Black-Right-Pointing-Pointer FeF{sub 2} gives oxides FeAl{sub 2}O{sub 4}, Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3}. Black-Right-Pointing-Pointer The participation of oxygen in the corrosion has not been observed. - Abstract: Corrosion destruction of two-component iron-based alloys used as an anode in high-temperature alumina electrolysis in the melt of NaF/KF/AlF{sub 3} electrolyte has been considered. Ni, Si, Cu, Cr, Mn, Al, Ti in the amount of up to 10% have been tested as the dopants to an anode alloys. The composition of the corrosion products has been studied using X-ray diffraction, scanning electron microscopy and electron microprobe analysis. It has been established that the anode corrosion is induced by a surface electrochemical polarization and iron atom oxidation. Iron ions come into an exchange interaction with the fluoride components of the melted electrolyte, producing FeF{sub 2}. The last interacts with oxyfluoride species transforming into the oxide forms: FeAl{sub 2}O{sub 4}, Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3}. Due to the low solubility, the iron oxides are accumulated in the near-electrode sheath. The only small part of iron from anode migrates to cathode that makes an production of high purity aluminum of a real task. The alloy dopants are also subjected to corrosion in accordance with electromotive series resulting corrosion tunnels on the anode surface. The oxides are final compounds which collect in the same area. The corrosion products form an anode shell which is electronic conductor at electrolysis temperature. The

  8. Formation of poorly crystalline iron monosulfides: Surface redox reactions on high purity iron, spectroelectrochemical studies

    Energy Technology Data Exchange (ETDEWEB)

    Hansson, E.B. [Geological Institute, University of Copenhagen, Oster Voldgade 10, Copenhagen K, DK-1350 (Denmark); Odziemkowski, M.S. [Department of Earth Sciences, University of Waterloo, Waterloo, Ont., N2L 3G1 (Canada)]. E-mail: marek@sciborg.uwaterloo.ca; Gillham, R.W. [Department of Earth Sciences, University of Waterloo, Waterloo, Ont., N2L 3G1 (Canada)

    2006-11-15

    In the use of iron for reductive dehalogenation of chlorinated solvents in ground water, due to presence of sulfate-reducing bacteria the formation of hydrogen sulfide is expected. To simulate those processes the interface between 99.99% pure iron and 0.1 M NaHCO{sub 3} deoxygenated solution with 3.1 x 10{sup -5}-7.8 x 10{sup -3} M Na{sub 2}S . 9H{sub 2}O added was studied. The surface processes were characterised by the in situ normal Raman spectroscopy (NRS) and ex situ techniques; X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray (EDX). The open circuit potential (OCP) was monitored during in situ NRS measurements, and potentiodynamic anodic polarization measurements were carried out to reveal electrochemical behaviour of iron electrode. Open circuit potential-time transients indicated that the native oxide is unstable in deaerated bicarbonate solution and undergoes reductive dissolution (i.e. autoreduction) leaving the metallic Fe covered by Fe(OH){sub 2}, adsorbed OH{sup -}, and patches of 'magnetite-like' oxide. Immediately upon injection of the Na{sub 2}S-solution the iron interface undergoes complex redox surface processes and a poorly crystalline FeS film forms. Potentiodynamic anodic polarization measurements indicated a mechanical breakdown of the FeS film. The origin and initiation of this breakdown process is not clear but is probably a result of internal stress developed during film growth. Based on surface studies supported by electrochemical measurements, a conceptual model for the complex redox processes occurring at the iron interface is proposed. This model describes the structural development of a poorly crystalline FeS, which breaks down, allowing further dissolution of the Fe and formation of FeOOH at the interface. Simultaneously and despite the existence of thick layer of FeS the entrance of hydrogen was evident as the typical hydrogen cracks in bulk of the

  9. SHORT COMMUNICATION DETERMINATION OF IRON IN ...

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    A fluorescence quenching method was developed for determination of Fe3+ ... 20 to 200 μg/L. The detection limit was 8.3 μg/L. This method has been ... Fe3+ has been established based upon the investigation of the system of Fe3+-KI-R6G.

  10. In-situ surface hardening of cast iron by surface layer metallurgy

    International Nuclear Information System (INIS)

    Fischer, Sebastian F.; Muschna, Stefan; Bührig-Polaczek, Andreas; Bünck, Matthias

    2014-01-01

    Abrasive wear is a serious problem in many cast iron castings used in industry. To minimize failure and repair of these components, different strategies exist to improve their surface microhardness thus enhancing their wear resistance. However, most of these methods lead to very brittle and/or expensive castings. In the current work a new method for surface hardening is presented which utilizes surface layer metallurgy to generate in-situ a boron-enriched white cast iron surface layer with a high microhardness on a gray cast iron casting. To do this, sand molds are coated with a ferroboron suspension and cast with a cast iron melt. After solidification, a 100–900 µm thick layer of boron-enriched ledeburite is formed on the surface of the casting which produces an increase in the average microhardness from 284 HV 0.1 ±52 HV 0.1 to 505 HV 0.1 ±87 HV 0.1 . Analyses of the samples' core reveal a typical cast iron microstructure which leads to the conclusion that the coating mainly affects the castings' surface. By varying the grain size of the ferroboron powder in the coatings, it is shown that a powder size ≤100 µm is most suitable to create a boron-enriched ledeburite surface layer possessing high hardness values

  11. Designing porous metallic glass compact enclosed with surface iron oxides

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jae Young; Park, Hae Jin; Hong, Sung Hwan; Kim, Jeong Tae; Kim, Young Seok; Park, Jun-Young; Lee, Naesung [Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Seo, Yongho [Graphene Research Institute (GRI) & HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Park, Jin Man, E-mail: jinman_park@hotmail.com [Global Technology Center, Samsung Electronics Co., Ltd, 129 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-742 (Korea, Republic of); Kim, Ki Buem, E-mail: kbkim@sejong.ac.kr [Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 143-747 (Korea, Republic of)

    2015-06-25

    Highlights: • Porous metallic glass compact was developed using electro-discharge sintering process. • Uniform PMGC can only be achieved when low electrical input energy was applied. • Functional iron-oxides were formed on the surface of PMGCs by hydrothermal technique. - Abstract: Porous metallic glass compact (PMGC) using electro-discharge sintering (EDS) process of gas atomized Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} metallic glass powder was developed. The formation of uniform PMGC can only be achieved when low electrical input energy was applied. Functional iron-oxides were formed on the surface of PMGCs by hydrothermal technique. This finding suggests that PMGC can be applied in the new area such as catalyst via hydrothermal technique and offer a promising guideline for using the metallic glasses as a potential functional application.

  12. Microstructure and properties of cast iron after laser surface hardening

    Directory of Open Access Journals (Sweden)

    Stanislav

    2013-12-01

    Full Text Available Laser surface hardening of cast iron is not trivial due to the material’s heterogeneity and coarse-grained microstructure, particularly in massive castings. Despite that, hardening of heavy moulds for automotive industry is in high demand. The present paper summarises the findings collected over several years of study of materials structure and surface properties. Phase transformations in the vicinity of graphite are described using examples from production of body parts in automotive industry. The description relates to formation of martensite and carbide-based phases, which leads to hardness values above 65 HRC and to excellent abrasion resistance.

  13. Surface functionalization of dopamine coated iron oxide nanoparticles for various surface functionalities

    Energy Technology Data Exchange (ETDEWEB)

    Sherwood, Jennifer; Xu, Yaolin; Lovas, Kira [Chemical and Biological Engineering, The University of Alabama, Tuscaloosa , AL 35487 (United States); Qin, Ying [Alabama Innovation and Mentoring of Entrepreneurs, The University of Alabama, Tuscaloosa, AL 35487 (United States); Bao, Yuping, E-mail: ybao@eng.ua.edu [Chemical and Biological Engineering, The University of Alabama, Tuscaloosa , AL 35487 (United States)

    2017-04-01

    We present effective conjugation of four small molecules (glutathione, cysteine, lysine, and Tris(hydroxymethyl)aminomethane) onto dopamine-coated iron oxide nanoparticles. Conjugation of these molecules could improve the surface functionality of nanoparticles for more neutral surface charge at physiological pH and potentially reduce non-specific adsorption of proteins to nanoparticles surfaces. The success of conjugation was evaluated with dynamic light scattering by measuring the surface charge changes and Fourier transform infrared spectroscopy for surface chemistry analysis. The stability of dopamine-coated nanoparticles and the ability of conjugated nanoparticles to reduce the formation of protein corona were evaluated by measuring the size and charge of the nanoparticles in biological medium. This facile conjugation method opens up possibilities for attaching various surface functionalities onto iron oxide nanoparticle surfaces for biomedical applications.

  14. Surface functionalization of dopamine coated iron oxide nanoparticles for various surface functionalities

    International Nuclear Information System (INIS)

    Sherwood, Jennifer; Xu, Yaolin; Lovas, Kira; Qin, Ying; Bao, Yuping

    2017-01-01

    We present effective conjugation of four small molecules (glutathione, cysteine, lysine, and Tris(hydroxymethyl)aminomethane) onto dopamine-coated iron oxide nanoparticles. Conjugation of these molecules could improve the surface functionality of nanoparticles for more neutral surface charge at physiological pH and potentially reduce non-specific adsorption of proteins to nanoparticles surfaces. The success of conjugation was evaluated with dynamic light scattering by measuring the surface charge changes and Fourier transform infrared spectroscopy for surface chemistry analysis. The stability of dopamine-coated nanoparticles and the ability of conjugated nanoparticles to reduce the formation of protein corona were evaluated by measuring the size and charge of the nanoparticles in biological medium. This facile conjugation method opens up possibilities for attaching various surface functionalities onto iron oxide nanoparticle surfaces for biomedical applications.

  15. Surface oxidation phenomena of boride coatings grown on iron

    International Nuclear Information System (INIS)

    Carbucicchio, M.; Palombarini, G.; Sambogna, G.

    1992-01-01

    Very hard boride coatings are grown on various metals using thermochemical as well as chemical vapour deposition techniques. In this way many surface properties, and in particular the wear resistance, can be considerably improved. Usually, also the corrosion behaviour of the treated components is important. In particular, oxidizing atmospheres are involved in many applications where, therefore, coating-environment interactions can play a relevant role. In a previous work, the early stages of the oxidation of iron borides were studied by treating single phase compacted powders in flowing oxygen at low temperatures (300-450deg C). In the present paper, the attention is addressed to the oxidation of both single phase and polyphase boride coatings thermochemically grown on iron. The single phase boride coatings were constituted by Fe 2 B, while the polyphase coatings were constituted by an inner Fe 2 B layer and an outer FeB-base layer. All the boride layers displayed strong (002) preferred crystallographic orientations. (orig.)

  16. Proton and temperature-induced competitive segregation of iron on surface and volume sinks of silica

    International Nuclear Information System (INIS)

    Shilobreeva, S.N.; Kashkarov, L.L.; Barabanenkov, M.Yu.; Pustovit, A.N.; Zinenko, V.I.; Agafonov, Yu.A.

    2007-01-01

    Experimental results are delivered on iron redistribution in silica for proton irradiation followed by thermal annealing. Iron ions are initially implanted into silica at room temperature. Proton irradiation is performed at different temperatures. It is demonstrated, in particular, that radiation-induced migration of iron is more efficient at low temperature. Iron surface segregation and capture of iron by sinks in silica subsurface region during thermal annealing are speculated in terms of diffusion-alternative-sinks problem

  17. Proton and temperature-induced competitive segregation of iron on surface and volume sinks of silica

    Energy Technology Data Exchange (ETDEWEB)

    Shilobreeva, S.N. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, ul. Kosygina 19, Moscow 117975 (Russian Federation); Kashkarov, L.L. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, ul. Kosygina 19, Moscow 117975 (Russian Federation); Barabanenkov, M.Yu. [Institute of Microelectronics Technology and Superpure Materials, Russian Academy of Sciences, 142432 Chernogolovka, Moscow Region (Russian Federation)]. E-mail: barab@ipmt-hpm.ac.ru; Pustovit, A.N. [Institute of Microelectronics Technology and Superpure Materials, Russian Academy of Sciences, 142432 Chernogolovka, Moscow Region (Russian Federation); Zinenko, V.I. [Institute of Microelectronics Technology and Superpure Materials, Russian Academy of Sciences, 142432 Chernogolovka, Moscow Region (Russian Federation); Agafonov, Yu.A. [Institute of Microelectronics Technology and Superpure Materials, Russian Academy of Sciences, 142432 Chernogolovka, Moscow Region (Russian Federation)

    2007-03-15

    Experimental results are delivered on iron redistribution in silica for proton irradiation followed by thermal annealing. Iron ions are initially implanted into silica at room temperature. Proton irradiation is performed at different temperatures. It is demonstrated, in particular, that radiation-induced migration of iron is more efficient at low temperature. Iron surface segregation and capture of iron by sinks in silica subsurface region during thermal annealing are speculated in terms of diffusion-alternative-sinks problem.

  18. Development of a method for determination of metallic iron content within hot briquette iron (HBI for steelmaking

    Directory of Open Access Journals (Sweden)

    Morcali M.H.

    2016-01-01

    Full Text Available The growing use of metallic iron in metallurgy and industrial chemical applications requires a fast, easy and cheap method for the determination of metallic iron, not merely in recyclable materials, such as iron pellets, reduced iron mill scale dust, electric arc furnace dust and pig iron, but from hot briquette iron (HBI as well. This study investigates a new method for determination of metallic iron within HBI used for steel-making materials. The effects of reaction time, temperature, and stirring rate were studied. The concentration of iron was determined via Atomic Absorption Spectroscopy (AAS. After the optimization study, high-purity metallic iron powder (Sigma-Aldrich, PubChem Substance ID 24855469 was used to compare efficiencies and identify the optimum conditions; The present study was matched with international standard methods (BS ISO 5416:2006, IS 15774:2007. Results were consistent with certified values and metallic iron content could be determined within the 95% confidence level. The purposed method is easy, straightforward, and cheap.

  19. Experimental Research on the Determination of the Coefficient of Sliding Wear under Iron Ore Handling Conditions

    Directory of Open Access Journals (Sweden)

    G. Chen

    2017-09-01

    Full Text Available The handling of iron ore bulk solids maintains an increasing trend due to economic development. Because iron ore particles have hard composites and irregular shapes, the bulk solids handling equipment surface can suffer from severe sliding wear. Prediction of equipment surface wear volume is beneficial to the efficient maintenance of worn areas. Archard’s equation provides a theoretical solution to predict wear volume. To use Archard’s equation, the coefficient of sliding wear must be determined. To our best knowledge, the coefficient of sliding wear for iron ore handling conditions has not yet been determined. In this research, using a pin-on-disk tribometer, the coefficients of sliding wear for both Sishen particles and mild steel are determined with regard to iron ore handling conditions. Both naturally irregular and spherical shapes of particles are used to estimate average values of wear rate. Moreover, the hardness and inner structures of Sishen particles are examined, which adds the evidence of the interpretation of wear results. It is concluded that the coefficients of sliding wear can vary largely for both Sishen particle and mild steel. The wear rate decreases from transient- to steady-state. The average coefficient of sliding wear is capable of predicting wear with respect to long distances at the steady-state. Two types of sliding friction are distinguished. In addition, it is found that the temperature rise of the friction pairs has negligible influence on wear rate.

  20. The determination of iron in zircon beach sands and its leachability

    International Nuclear Information System (INIS)

    Dixon, K.; Royal, S.J.; Komarkova, E.; Austen, C.E.; Watson, A.E.

    1977-01-01

    The determination of iron in the range 0,05 to 0,20 per cent by spectrophotometric, atomic-absorption-spectrophotometric, and X-ray-fluorescence procedures was examined. The methods finally developed give consistent results and have a precision varying from 2 to 5 per cent. A preliminary examination was made in this application of emission spectrography with an induction-coupled plasma torch as the source. X-ray and emission spectrography were found to give the most rapid routine control, although the atomic-absorption procedure is currently the best referee method. It was concluded that sample variability is insufficient to account for the wide differences normally observed in the analyses for iron by different laboratories. The laboratory leaching test developed indicates that all the surface iron is removed after a digestion period of 1 hour in hydrochloric acid

  1. Fob1 and Fob2 Proteins Are Virulence Determinants of Rhizopus oryzae via Facilitating Iron Uptake from Ferrioxamine.

    Directory of Open Access Journals (Sweden)

    Mingfu Liu

    2015-05-01

    Full Text Available Dialysis patients with chronic renal failure receiving deferoxamine for treating iron overload are uniquely predisposed for mucormycosis, which is most often caused by Rhizopus oryzae. Although the deferoxamine siderophore is not secreted by Mucorales, previous studies established that Rhizopus species utilize iron from ferrioxamine (iron-rich form of deferoxamine. Here we determined that the CBS domain proteins of Fob1 and Fob2 act as receptors on the cell surface of R. oryzae during iron uptake from ferrioxamine. Fob1 and Fob2 cell surface expression was induced in the presence of ferrioxamine and bound radiolabeled ferrioxamine. A R. oryzae strain with targeted reduced Fob1/Fob2 expression was impaired for iron uptake, germinating, and growing on medium with ferrioxamine as the sole source of iron. This strain also exhibited reduced virulence in a deferoxamine-treated, but not the diabetic ketoacidotic (DKA, mouse model of mucormycosis. The mechanism by which R. oryzae obtains iron from ferrioxamine involves the reductase/permease uptake system since the growth on ferrioxamine supplemented medium is associated with elevated reductase activity and the use of the ferrous chelator bathophenanthroline disulfonate abrogates iron uptake and growth on medium supplemented with ferrioxamine as a sole source of iron. Finally, R. oryzae mutants with reduced copies of the high affinity iron permease (FTR1 or with decreased FTR1 expression had an impaired iron uptake from ferrioxamine in vitro and reduced virulence in the deferoxamine-treated mouse model of mucormycosis. These two receptors appear to be conserved in Mucorales, and can be the subject of future novel therapy to maintain the use of deferoxamine for treating iron-overload.

  2. Influence of surface topography on the surface durability of steam oxidised sintered iron

    Directory of Open Access Journals (Sweden)

    José Daniel Biasoli de Mello

    2005-06-01

    Full Text Available Durability of surfaces has been reported as the main factor affecting tribological behavior of steam oxidised sintered iron. The presence of surface pores and their negative influence on load bearing capacity, suggest that surface topography might play an important role on the durability of the oxide layer. In this paper, the influence of compaction pressure and powder grade on surface topography, and as a consequence, its effect on the tribological behavior of steam oxidised sintered iron has been analysed. Specimens prepared from atomised iron powders with different sizes were compacted using 4 different pressures, sintered, and then subjected to steam treatment. Tribological characterisation was carried out in a reciprocating sliding wear test. Although the processing parameters affected the surface topography to a considerable extent, the main influence may be attributed to powder grade. A strong influence of surface topography on the durability distance, evaluated in terms of the evolution of contact resistance with total sliding distance, has been highlighted. Surfaces which were smoother and had high load-carrying capacity were always associated with a higher durability distance.

  3. Determination of retinal surface area.

    Science.gov (United States)

    Nagra, Manbir; Gilmartin, Bernard; Thai, Ngoc Jade; Logan, Nicola S

    2017-09-01

    Previous attempts at determining retinal surface area and surface area of the whole eye have been based upon mathematical calculations derived from retinal photographs, schematic eyes and retinal biopsies of donor eyes. 3-dimensional (3-D) ocular magnetic resonance imaging (MRI) allows a more direct measurement, it can be used to image the eye in vivo, and there is no risk of tissue shrinkage. The primary purpose of this study is to compare, using T2-weighted 3D MRI, retinal surface areas for superior-temporal (ST), inferior-temporal (IT), superior-nasal (SN) and inferior-nasal (IN) retinal quadrants. An ancillary aim is to examine whether inter-quadrant variations in area are concordant with reported inter-quadrant patterns of susceptibility to retinal breaks associated with posterior vitreous detachment (PVD). Seventy-three adult participants presenting without retinal pathology (mean age 26.25 ± 6.06 years) were scanned using a Siemens 3-Tesla MRI scanner to provide T2-weighted MR images that demarcate fluid-filled internal structures for the whole eye and provide high-contrast delineation of the vitreous-retina interface. Integrated MRI software generated total internal ocular surface area (TSA). The second nodal point was used to demarcate the origin of the peripheral retina in order to calculate total retinal surface area (RSA) and quadrant retinal surface areas (QRSA) for ST, IT, SN, and IN quadrants. Mean spherical error (MSE) was -2.50 ± 4.03D and mean axial length (AL) 24.51 ± 1.57 mm. Mean TSA and RSA for the RE were 2058 ± 189 and 1363 ± 160 mm 2 , respectively. Repeated measures anova for QRSA data indicated a significant difference within-quadrants (P area/mm increase in AL. Although the differences between QRSAs are relatively small, there was evidence of concordance with reported inter-quadrant patterns of susceptibility to retinal breaks associated with PVD. The data allow AL to be converted to QRSAs, which will assist further

  4. Changes on iron electrode surface during hydrogen permeation in borate buffer solution

    International Nuclear Information System (INIS)

    Modiano, S.; Carreno, J.A.V.; Fugivara, C.S.; Torresi, R.M.; Vivier, V.; Benedetti, A.V.; Mattos, O.R.

    2008-01-01

    Hydrogen interaction with oxide films grown on iron electrodes at open circuit potential (E oc ) and in the passive region (+0.30 V ECS ) was studied by chronopotentiometry, chronoamperometry and electrochemical impedance spectroscopy techniques. The results were obtained in deaerated 0.3 mol L -1 H 3 BO 3 + 0.075 mol L -1 Na 2 B 4 O 7 (BB, pH 8.4) solution before, during and after hydrogen permeation. The iron oxide film modification was also investigated by means of in situ X-ray absorption near-edge spectroscopy (XANES) and scanning electrochemical microscopy (SECM) before and during hydrogen permeation. The main conclusion was that the passive film is reduced during the hydrogen diffusion. The hydrogen permeation stabilizes the iron surface at a potential close to the thermodynamic water stability line where hydrogen evolution can occur. The stationary condition required for the determination of the permeation parameters cannot be easily attained on iron surface during hydrogen permeation. Moreover, additional attention must be paid when obtaining the transport parameters using the classical permeation cell

  5. Theoretical Investigation of Hydrogen Adsorption and Dissociation on Iron and Iron Carbide Surfaces Using the ReaxFF Reactive Force Field Method

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Chenyu; van Duin, Adri C.T.; Sorescu, Dan C.

    2012-06-01

    We have developed a ReaxFF reactive force field to describe hydrogen adsorption and dissociation on iron and iron carbide surfaces relevant for simulation of Fischer–Tropsch (FT) synthesis on iron catalysts. This force field enables large system (>>1000 atoms) simulations of hydrogen related reactions with iron. The ReaxFF force field parameters are trained against a substantial amount of structural and energetic data including the equations of state and heats of formation of iron and iron carbide related materials, as well as hydrogen interaction with iron surfaces and different phases of bulk iron. We have validated the accuracy and applicability of ReaxFF force field by carrying out molecular dynamics simulations of hydrogen adsorption, dissociation and recombination on iron and iron carbide surfaces. The barriers and reaction energies for molecular dissociation on these two types of surfaces have been compared and the effect of subsurface carbon on hydrogen interaction with iron surface is evaluated. We found that existence of carbon atoms at subsurface iron sites tends to increase the hydrogen dissociation energy barrier on the surface, and also makes the corresponding hydrogen dissociative state relatively more stable compared to that on bare iron. These properties of iron carbide will affect the dissociation rate of H{sub 2} and will retain more surface hydride species, thus influencing the dynamics of the FT synthesis process.

  6. Iron

    Science.gov (United States)

    Iron is a mineral that our bodies need for many functions. For example, iron is part of hemoglobin, a protein which carries ... It helps our muscles store and use oxygen. Iron is also part of many other proteins and ...

  7. Calculated electronic structure of chromium surfaces and chromium monolayers on iron

    International Nuclear Information System (INIS)

    Victora, R.H.; Falicov, L.M.

    1985-01-01

    A self-consistent calculation of the magnetic and electronic properties of the chromium (100) and (110) surfaces and of a chromium monolayer on the (100) and (110) iron surfaces is presented. It is found that (i) the (100) chromium surface is ferromagnetic with a greatly enhanced spin polarization (3.00 electrons); (ii) a substantial enhancement of the spin imbalance exists several (>5) layers into the bulk; (iii) the (110) chromium surface is antiferromagnetic with a large (2.31) spin imbalance; (iv) the (100) chromium monolayer on ferromagnetic iron is ferromagnetic, with a huge spin imbalance (3.63), and aligned antiferromagnetically with respect to the bulk iron; (v) the (110) chromium monolayer on ferromagnetic iron is also ferromagnetic, with a spin imbalance of 2.25 and antiferromagnetically aligned to the iron. The spin imbalance of chromium on iron (100) is possibly the largest of any transition-metal system

  8. Voltammetric determination of arsenic in high iron and manganese groundwaters.

    Science.gov (United States)

    Gibbon-Walsh, Kristoff; Salaün, Pascal; Uroic, M Kalle; Feldmann, Joerg; McArthur, John M; van den Berg, Constant M G

    2011-09-15

    Determination of the speciation of arsenic in groundwaters, using cathodic stripping voltammetry (CSV), is severely hampered by high levels of iron and manganese. Experiments showed that the interference is eliminated by addition of EDTA, making it possible to determine the arsenic speciation on-site by CSV. This work presents the CSV method to determine As(III) in high-iron or -manganese groundwaters in the field with only minor sample treatment. The method was field-tested in West-Bengal (India) on a series of groundwater samples. Total arsenic was subsequently determined after acidification to pH 1 by anodic stripping voltammetry (ASV). Comparative measurements by ICP-MS as reference method for total As, and by HPLC for its speciation, were used to corroborate the field data in stored samples. Most of the arsenic (78±0.02%) was found to occur as inorganic As(III) in the freshly collected waters, in accordance with previous studies. The data shows that the modified on-site CSV method for As(III) is a good measure of water contamination with As. The EDTA was also found to be effective in stabilising the arsenic speciation for longterm sample storage at room temperature. Without sample preservation, in water exposed to air and sunlight, the As(III) was found to become oxidised to As(V), and Fe(II) oxidised to Fe(III), removing the As(V) by adsorption on precipitating Fe(III)-hydroxides within a few hours. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Determination of sulfur isotopic composition for the study of iron sulfides origin, biotic or abiotic, in anoxic corrosion

    International Nuclear Information System (INIS)

    Grousset, Sophie

    2016-01-01

    The first goal of this project was to develop a methodology based on the study of the sulfur isotopic composition enabling the determination of iron sulfides origin, biotic or abiotic, within the corrosion products layers (CPL). Then, the aim was to apply this methodology to real corrosion systems in order to determine the mechanisms of iron sulfides formation. Sulfur isotopic analyses methodologies, adapted to micrometric iron sulfides layers observed in real corrosion systems, were developed in nanoSIMS and ToF-SIMS. The study of iron sulfides formed in anoxic carbonated medium with or without sulphate-reducing bacteria validated the use of these methods for the determination of iron sulfides origin. The application of these methods coupled with the precise characterization of irons sulfides formed in the real corrosion systems show two kind of corrosion pattern. In pattern 1, the iron sulfides are localized in the external part of the CPL. They result from the Fe 2+ migration from the metal surface to areas rich in biotic S 2- . In this pattern, corrosion rates are lower than 20 μm/year for laboratory systems, and lower than 5 μm/year for archaeological objects. In pattern 2, the large presence of conductive phases in the CPL results in the delocalization of electrons, and so a disequilibrium of the charges at the metal's surface. That leads to the migration of biotic S 2- in the CPL till the metal where they precipitate in iron sulphides. This pattern shows high corrosion rates (∼100 μm/an) that might be resulting from the accumulation of bio-corrosion and chloride corrosion mechanisms. (author) [fr

  10. DETERMINATION OF RADIATOR COOLING SURFACE

    Directory of Open Access Journals (Sweden)

    A. I. Yakubovich

    2009-01-01

    Full Text Available The paper proposes a methodology for calculation of a radiator cooling surface with due account of heat transfer non-uniformity on depth of its core. Calculation of radiator cooling surfaces of «Belarus-1221» and «Belarus-3022» tractors has been carried out in the paper. The paper also advances standard size series of radiators for powerful «Belarus» tractor type.

  11. Determination of aluminium in iron ores and ferroalloys by complexometry

    International Nuclear Information System (INIS)

    Tikhonov, V.N.; Grigorovich, L.F.

    1977-01-01

    The present method is based on fusing iron ore samples and ferroalloys with NaOH, leaching of the alloy in water, and complexometric estimation of aluminium in the filtrate by back titration of excess EDTA with a CuSO 4 solution in the presence of a glycine-thymol blue tracer, using NaF to increase selectivity. The final titration point is fixed by means of a photoelectrical titrator. Fifty-fold amounts of Cu(2), Mg, Zn, In, Pb, Fe(3) and Ni, twenty-five-fold amounts of Ca, Sr and Cd, ten-fold amounts of Co, five-fold amounts of Hg(2), Bi and Mo(6), two-fold amounts of Mn, and equal amounts of Ga, Tl(3), Zr, V(5) and W(6) do not impede determination. Determination is impeded by metals that form strong fluoride complexes with Sc, Y, rare-earth elements, Ti(4), Sn(2) and V(4), even when those metals are contained in equal amounts; it is also impeded by equal amounts of Cr(3). The selectivity of the given method has been compared with that of methods involving titration with a solution constituting zinc chloride with xylenol orange and with a solution comprising copper chloride and sulphur chrome-azurol in the presence of cytil trimethyl ammonium. The method is more selective. A hexamethylenetetramine buffer solution has been used to obtain an optimum (pH 6) medium. The above procedure is employed to assay standard ferroboron samles of iron ore

  12. Silane surface modification effects on the electromagnetic properties of phosphatized iron-based SMCs

    Science.gov (United States)

    Fan, Liang-Fang; Hsiang, Hsing-I.; Hung, Jia-Jing

    2018-03-01

    It is difficult to achieve homogeneous phosphatized iron powder dispersion in organic resins during the preparation of soft magnetic composites (SMCs). Inhomogeneous iron powder mixing in organic resins generally leads to the formation of micro-structural defects in SMCs and hence causes the magnetic properties to become worse. Phosphatized iron powder dispersion in organic resins can be improved by coating the phosphatized iron powder surfaces with a coupling agent. This study investigated the (3-aminopropyl) triethoxysilane (APTES) surface modification effects on the electromagnetic properties of phosphatized iron-based soft magnetic composites (SMCs). The results showed that the phosphatized iron powder surface can be modified using APTES to improve the phosphatized iron powder and epoxy resin compatibility and hence enhance phosphate iron powder epoxy mixing. The tensile strength, initial permeability, rated current under DC-bias superposition and magnetic loss in SMCs prepared using phosphatized iron powders can be effectively improved using APTES surface modification, which provides a promising candidate for power chip inductor applications.

  13. Determination of iron in plutonium by extraction of the Fe (2): Bathophenanthroline complex

    International Nuclear Information System (INIS)

    Pichotin, B.; Chasseur, Ph.

    1966-06-01

    The present report describes the method to determine micro quantities of iron in plutonium, by extraction with hexyl alcohol of the complex that give iron (II) with bathophenanthroline (4,7 diphenyl - 1.10 phenanthroline). The reagent has been applied to the determination of amounts of iron ranging from 1 to 10 μg in 20 ml of solvent The determination is made by spectrophotometry at 530 mμ. Others cations present do not interfere. (authors) [fr

  14. Effect of the Surface Layer of Iron Casting on the Growth of Protective Coating During Hot-Dip Galvanizing

    Directory of Open Access Journals (Sweden)

    Kopyciński D.

    2016-03-01

    Full Text Available The paper presents the results of investigations of the growth of protective coating on the surface of ductile iron casting during the hot-dip galvanizing treatment. Ductile iron of the EN-GJS-600-3 grade was melted and two moulds made by different technologies were poured to obtain castings with different surface roughness parameters. After the determination of surface roughness, the hot-dip galvanizing treatment was carried out. Based on the results of investigations, the effect of casting surface roughness on the kinetics of the zinc coating growth was evaluated. It was found that surface roughness exerts an important effect on the thickness of produced zinc coating.

  15. Spectrophotometric determination of iron (III) in tap water using 8 ...

    African Journals Online (AJOL)

    ajl yemi

    2011-11-14

    Nov 14, 2011 ... Beers law was obeyed in the range of 1 to 14 ug/ml Fe3+. The recovery was between 98.60 ... Federal and state regulations limit the iron content of drinking water to <1 ppm, though iron is easily .... weighed and dissolved in chloroform in a 100 ml volumetric flask and made up to the mark with chloroform.

  16. EVALUATION OF MACHINABILITY OF DUCTILE IRONS ALLOYED WITH Ni AND Cu IN TERMS OF CUTTING FORCES AND SURFACE QUALITY

    Directory of Open Access Journals (Sweden)

    Yücel AŞKUN

    2003-02-01

    Full Text Available Due to the enhanced strength, ductility and thoughness of Ductile Iron (DI when compared to the other types cast iron, its machinability is relatively poor. When a steel part is replaced with ductile iron, however, better machinability is considered to be the most important gain. This study presents the results of machining tests of ductile irons alloyed with Ni and Cu at various contents to determine the effect of their microstructure and mechanical properties on cutting forces and surface roughness. Six different specimen groups of ductile iron alloyed with various amounts of nickel and copper were subjected to machining tests and their machinabilities were investigated based on cutting forces and surface roughness criteria. The results were evaluated according to microstructure and mechanical properties of specimens determined before. In terms of both criterion, the best result obtained was specimen added 0.7 % Ni and 0.7 % Cu. When the specimens were evaluated according to their mechanical properties, the specimens alloyed 1 % Ni and 0.65 % Cu seemed promising.

  17. Influence of the Lubricant Type on the Surface Quality of Steel Parts Obtained by Ironing

    Directory of Open Access Journals (Sweden)

    D. Adamović

    2015-06-01

    Full Text Available If it is needed to achieve a higher strain rate during the ironing process, which is possible without inter-stage annealing, the ironing is performed in succession through multiple dies. During that process, changes of friction conditions occur due to the change of contact conditions (dislodging of lubricants, changes of surface roughness, formation of friction junctions, etc.. In the multistage ironing, after each stage, the completely new conditions on the contact surfaces occur, which will significantly affect the quality of the workpiece surface. Lubricant has a very important role during the steel sheet metal ironing process; to separate the sheet metal surface from the tool and to reduce the friction between the contact surfaces. The influence of tribological conditions in ironing process is extremely important and it was a subject of study among researches in recent years, both in the real processes and on the tribo-models. Investigation of tribological conditions in the real processes is much longer and more expensive, so testing on the tribo-models is more frequent. Experimental research on the original tribo-model presented in this paper was aimed to indicate the changes that occur during multistage ironing, as well as to consider the impact of some factors (tool material, lubricant on die and punch on increase or decrease of the sheet metal surface roughness in ironing stages.

  18. Device for continuous radiometric determination of the calcium and iron content in raw slurry for cement

    International Nuclear Information System (INIS)

    Wasilewska, M.; Ostachowicz, J.; Lankosz, M.; Molodynska, W.

    1975-01-01

    The characteristic iron and calcium-K series were excited using a Cd-109 isotope source. In order to determine the calcium and iron content in dry slurry, the Compton-effect scattered radiation of the Cd-109 source in the sample was used. A numerical process was worked out which allowed the elimination of the influence of changing contents of iron and water on the results of the calcium content determinations, and a device for continuous radiometric determination of calcium and iron in raw slurry was designed and constructed. The device was installed in the cement plant 'Przyjazn' under technical measuring conditions and its applicability was tested. (orig./LH) [de

  19. Microstructure and hardness of WC-Co particle reinforced iron matrix surface composite

    Directory of Open Access Journals (Sweden)

    Zhang Peng

    2013-11-01

    Full Text Available In this study, a high Cr cast iron surface composite material reinforced with WC-Co particles 2-6 mm in size was prepared using a pressureless sand mold infiltration casting technique. The composition, microstructure and hardness were determined by means of energy dispersive spectrometry (EDS, electron probe microanalysis (EPMA, scanning electron microscope (SEM and Rockwell hardness measurements. It is determined that the obtained composite layer is about 15 mm thick with a WC-Co particle volumetric fraction of ~38%. During solidification, interface reaction takes place between WC-Co particles and high chromium cast iron. Melting and dissolving of prefabricated particles are also found, suggesting that local Co melting and diffusion play an important role in promoting interface metallurgical bonding. The composite layer is composed of ferrite and a series of carbides, such as (Cr, W, Fe23C6, WC, W2C, M6C and M12C. The inhomogeneous hardness in the obtained composite material shows a gradient decrease from the particle reinforced metal matrix composite layer to the matrix layer. The maximum hardness of 86.3 HRA (69.5 HRC is obtained on the particle reinforced surface, strongly indicating that the composite can be used as wear resistant material.

  20. Determination of iron absorption and excretion by whole-body counting

    International Nuclear Information System (INIS)

    Hollard, D.; Benabid, Y.; Berard, M.; Bonnin, J.; Darnault, J.; Millet, M.

    1969-01-01

    Using a whole-body counter, the authors have studied 59 Fe absorption and loss in 8 normal subjects and in 30 iron deficient patients. Results showed that whole-body counting provided an excellent and simple method for iron retention measurements, obviating many inaccuracies of previous technic. Normal absorption of radio iron with this procedure has ranged from 9 per cent to 20 per cent of the administered tracer in normal subjects, with a mean of 15 per cent. A significant increase in 59 Fe absorption was noted in 21 iron-deficient patients in whom the retention ranged from 40 to 100 per cent. However, 3 iron-deficient patients were found to have low absorption, and their severe iron deficiency could be correlated with this defect in absorption. This method permits also the determination of the rate of iron excretion during the following months and therefore the study of the mechanism of some pathological loss. (authors) [fr

  1. Speciation and Determination of Low Concentration of Iron in Beer Samples by Cloud Point Extraction

    Science.gov (United States)

    Khalafi, Lida; Doolittle, Pamela; Wright, John

    2018-01-01

    A laboratory experiment is described in which students determine the concentration and speciation of iron in beer samples using cloud point extraction and absorbance spectroscopy. The basis of determination is the complexation between iron and 2-(5-bromo-2- pyridylazo)-5-diethylaminophenol (5-Br-PADAP) as a colorimetric reagent in an aqueous…

  2. Effects of high temperature surface oxides on room temperature aqueous corrosion and environmental embrittlement of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, R.A.; Perrin, R.L.

    1996-09-01

    Studies were conducted to determine the effects of high-temperature surface oxides, produced during thermomechanical processing, heat treatment (750 {degrees}C in air, one hour) or simulated in-service-type oxidation (1000{degrees}C in air, 24 hours) on the room-temperature aqueous-corrosion and environmental-embrittlement characteristics of iron aluminides. Materials evaluated included the Fe{sub 3}Al-based iron aluminides, FA-84, FA-129, FAL and FAL-Mo, a FeAl-based iron aluminide, FA-385, and a disordered low-aluminum Fe-Al alloy, FAPY. Tests were performed in a mild acid-chloride solution to simulate aggressive atmospheric corrosion. Cyclic-anodic-polarization tests were employed to evaluate resistances to localized aqueous corrosion. The high-temperature oxide surfaces consistently produced detrimental results relative to mechanically or chemically cleaned surfaces. Specifically, the pitting corrosion resistances were much lower for the as-processed and 750{degrees} C surfaces, relative to the cleaned surfaces, for FA-84, FA-129, FAL-Mo, FA-385 and FAPY. Furthermore, the pitting corrosion resistances were much lower for the 1000{degrees}C surfaces, relative to cleaned surfaces, for FA-129, FAL and FAL-Mo.

  3. Determination of ferrous and total iron in refractory spinels

    Energy Technology Data Exchange (ETDEWEB)

    Amonette, J.E. [Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Matyáš, J. [Material Science Department, Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2016-03-03

    Accurate and precise determination of the redox state of iron (Fe) in spinels presents a significant challenge due to their refractory nature. The resultant extreme conditions needed to obtain complete dissolution generally oxidize some of the Fe(II) initially present and thus prevent the use of colorimetric methods for Fe(II) measurements. To overcome this challenge we developed a hybrid oxidimetric/colorimetric approach, using Ag(I) as the oxidimetric reagent for determination of Fe(II) and 1,10-phenanthroline as the colorimetric reagent for determination of total Fe. This approach, which allows determination of Fe(II) and total Fe on the same sample, was tested on a series of four geochemical reference materials and then applied to the analysis of Fe(Ni) spinel crystals isolated from simulated high-level-waste (HLW) glass and of several reagent magnetites. Results for the reference materials were in excellent agreement with recommended values, with the exception of USGS BIR-1, for which higher Fe(II) values and lower total Fe values were obtained. The Fe(Ni) spinels showed Fe(II) values at the detection limit (ca. 0.03 wt% Fe) and total Fe values higher than obtained by ICP-AES analysis after decomposition by lithium metaborate/tetraborate fusion. For the magnetite samples, total Fe values were in agreement with reference results, but a wide range in Fe(II) values was obtained indicating various degrees of conversion to maghemite. Formal comparisons of accuracy and precision were made with 13 existing methods. Accuracy for Fe(II) and total Fe was at or near the top of the group. Precision varied with the parameter used to measure it but was generally in the middle to upper part of the group for Fe(II) while that for total Fe ranged from the bottom of the group to near the top. - Highlights: • Refractory samples, such as spinels, are the most difficult for Fe redox analysis. • Oxidimetric(Ag{sup +})/colorimetric (phen) method allows analysis of a single

  4. Characterisation by esca of iron componds formed on the nuclear steels by surface engeneering

    International Nuclear Information System (INIS)

    Minca, M.; Oncioiu, G.; Coaca, E.; Rusu, O.; Florea, S.; Andrei, V.

    2013-01-01

    In this work it is presented an approach for characterization of the oxide films by assigning the binding energy of the chemical states according with a theoretical analysis. In order to exemplify the method developed there are presented analyses on the internal standards a-Fe 2 O 3 and Fe 3 O 4 ), as well as analysis of superficial structure on austenitic steel samples on which different treatments of surface engineering were made. It is also presented a depth profiling analysis type, achieved by ball cratering method, which allow determining the distribution of different chemical elements with depth. One can follow the distribution of the valence states, Fe 2+ and Fe 3+ , with depth. By means of the presented method it can be precisely determined the valence states of Fe and their weight in the oxide iron films. (authors)

  5. Characterization of iron surface modified by 2-mercaptobenzothiazole self-assembled monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Feng Yuanyuan [Department of Chemistry, Shandong University, Jinan 250100 (China); Chen Shenhao [Department of Chemistry, Shandong University, Jinan 250100 (China) and State Key Laboratory for Corrosion and Protection, Shenyang 110016 (China)]. E-mail: shchen@sdu.edu.cn; Zhang Honglin [Department of Chemistry, Qufu Normal University, Qufu 273165 (China); Li Ping [Department of Chemistry, Shandong University, Jinan 250100 (China); Wu Ling [Department of Chemistry, Shandong University, Jinan 250100 (China); Guo Wenjuan [Department of Chemistry, Shandong University, Jinan 250100 (China)

    2006-12-30

    A self-assembled monolayer of 2-mercaptobenzothiazole (MBT) adsorbed on the iron surface was prepared. The films were characterized by electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared reflection spectroscopy (FT-IR) and scanning electron microscopy (SEM). Besides, the microcalorimetry method was utilized to study the self-assembled process on iron surface and the adsorption mechanism was discussed from the power-time curve. The results indicated that MBT was able to form a film spontaneously on iron surface and the presence of it could protect iron from corrosion effectively. However, the assembling time and the concentration influence the protection efficiency. Quantum chemical calculations, according to which adsorption mechanism was discussed, could explain the experimental results to some extent.

  6. Surface carbon influences on the reductive transformation of TCE in the presence of granular iron.

    Science.gov (United States)

    Firdous, R; Devlin, J F

    2018-04-05

    To gain insight into the processes of transformations in zero-valent iron systems, electrolytic iron (EI) has been used as a surrogate for the commercial products actually used in barriers. This substitution facilitates mechanistic studies, but may not be fully representative of all the relevant processes at work in groundwater remediation. To address this concern, the kinetic iron model (KIM) was used to investigate sorption and reactivity differences between EI and Connelly brand GI, using TCE as a probe compound. It was observed that retardation factors (R app ) for GI varied non-linearly with influent concentrations to the columns (C o ), and declined significantly as GI aged. In contrast, R app values for EI were small and insensitive to C o , and changed minimally with iron aging. Moreover, although declines in the rate constants (k) and increases in the sorption coefficients were observed for both iron types, they were most pronounced in the case of EI. SEM scans of the EI surface before and after aging (90 days) established the appearance of carbon on the older surface. This work provides evidence that iron with a higher surface carbon content outperforms pure iron, suggesting that the carbon is actively involved in promoting TCE reduction. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Iron

    DEFF Research Database (Denmark)

    Hansen, Jakob Bondo; Moen, I W; Mandrup-Poulsen, T

    2014-01-01

    and discuss recent evidence, suggesting that iron is a key pathogenic factor in both type 1 and type 2 diabetes with a focus on inflammatory pathways. Pro-inflammatory cytokine-induced β-cell death is not fully understood, but may include iron-induced ROS formation resulting in dedifferentiation by activation...... of transcription factors, activation of the mitochondrial apoptotic machinery or of other cell death mechanisms. The pro-inflammatory cytokine IL-1β facilitates divalent metal transporter 1 (DMT1)-induced β-cell iron uptake and consequently ROS formation and apoptosis, and we propose that this mechanism provides...

  8. Determination of iron redox ratio in borosilicate glasses and melts from Raman spectra

    Energy Technology Data Exchange (ETDEWEB)

    Cochain, B. [SCDV-Laboratoire d' Etudes de Base sur les Verres, CEA Valrho, Centre de Marcoule, 30207 Bagnols-sur-ceze (France); Physique des Mineraux et des Magmas, CNRS-IPGP, 4 place Jussieu, 75252 Paris Cedex05 (France); Neuville, D.R.; Richet, P. [Physique des Mineraux et des Magmas, CNRS-IPGP, 4 place Jussieu, 75252 Paris Cedex05 (France); Henderson, G.S. [Dept of Geology, University of Toronto, 22 Russell Street, Toronto (Canada); Pinet, O. [SCDV-Laboratoire d' Etudes de Base sur les Verres, CEA Valrho, Centre de Marcoule, 30207 Bagnols-sur-ceze (France)

    2008-07-01

    A method is presented to determine the redox ratio of iron in borosilicate glasses and melts relevant to nuclear waste storage from an analysis of Raman spectra recorded at room or high temperature. The basis of this method is the strong variation of the spectral feature observed between 800 and 1200 cm{sup -1}, in which it is possible to assign a band to vibrational modes involving ferric iron in tetrahedral coordination whose intensity increases with iron content and iron oxidation. After baseline correction and normalization, fits to the Raman spectra made with Gaussian bands enable us to determine the proportion of ferric iron provided the redox ratio is known independently for at least two redox states for a given glass composition. This method is particularly useful for in situ determinations of the kinetics and mechanisms of redox reactions. (authors)

  9. Determination of iron redox ratio in borosilicate glasses and melts from Raman spectra

    International Nuclear Information System (INIS)

    Cochain, B.; Neuville, D.R.; Richet, P.; Henderson, G.S.; Pinet, O.

    2008-01-01

    A method is presented to determine the redox ratio of iron in borosilicate glasses and melts relevant to nuclear waste storage from an analysis of Raman spectra recorded at room or high temperature. The basis of this method is the strong variation of the spectral feature observed between 800 and 1200 cm -1 , in which it is possible to assign a band to vibrational modes involving ferric iron in tetrahedral coordination whose intensity increases with iron content and iron oxidation. After baseline correction and normalization, fits to the Raman spectra made with Gaussian bands enable us to determine the proportion of ferric iron provided the redox ratio is known independently for at least two redox states for a given glass composition. This method is particularly useful for in situ determinations of the kinetics and mechanisms of redox reactions. (authors)

  10. Residual analysis applied to S-N data of a surface rolled cast iron

    Directory of Open Access Journals (Sweden)

    Omar Maluf

    2005-09-01

    Full Text Available Surface rolling is a process extensively employed in the manufacture of ductile cast iron crankshafts, specifically in regions containing stress concentrators with the main aim to enhance fatigue strength. Such process hardens and introduces compressive residual stresses to the surface as a result of controlled strains, reducing cyclic tensile stresses near the surface of the part. The main purpose of this work was to apply the residual analysis to check the suitability of the S-N approach to describe the fatigue properties of a surface rolled cast iron. The analysis procedure proved to be very efficient and easy to implement and it can be applied in the verification of any other statistical model used to describe fatigue behavior. Results show that the conventional S-N methodology is able to model the high cycle fatigue behavior of surface rolled notch testpieces of a pearlitic ductile cast iron submitted to rotating bending fatigue tests.

  11. Iron

    Science.gov (United States)

    ... Share: Search the ODS website Submit Search NIH Office of Dietary Supplements Consumer Datos en español Health ... eating a variety of foods, including the following: Lean meat, seafood, and poultry. Iron-fortified breakfast cereals ...

  12. Accurate determination of selenium and iron in erythrocytes from ...

    African Journals Online (AJOL)

    317 ng/ml while iron levels varied from 782 – 888 ng/ml. Accuracy of these results laws further confirmed by concurrent analysis of two reference materials with similar matrix composition and analyte levels. Nigerian Journal of Physics Vol.

  13. The effect of iron and copper impurities on the wettability of sphalerite (110) surface.

    Science.gov (United States)

    Simpson, Darren J; Bredow, Thomas; Chandra, Anand P; Cavallaro, Giuseppe P; Gerson, Andrea R

    2011-07-15

    The effect of impurities in the zinc sulfide mineral sphalerite on surface wettability has been investigated theoretically to shed light on previously reported conflicting results on sphalerite flotation. The effect of iron and copper impurities on the sphalerite (110) surface energy and on the water adsorption energy was calculated with the semi-empirical method modified symmetrically orthogonalized intermediate neglect of differential overlap (MSINDO) using the cyclic cluster model. The effect of impurities or dopants on surface energies is small but significant. The surface energy increases with increasing surface iron concentration while the opposite effect is reported for increasing copper concentration. The effect on adsorption energies is much more pronounced with water clearly preferring to adsorb on an iron site followed by a zinc site, and copper site least favorable. The theoretical results indicate that a sphalerite (110) surface containing iron is more hydrophilic than the undoped zinc sulfide surface. In agreement with the literature, the surface containing copper (either naturally or by activation) is more hydrophobic than the undoped surface. Copyright © 2011 Wiley Periodicals, Inc.

  14. Effect of inversion layer at iron pyrite surface on photovoltaic device

    Science.gov (United States)

    Uchiyama, Shunsuke; Ishikawa, Yasuaki; Uraoka, Yukiharu

    2018-03-01

    Iron pyrite has great potential as a thin-film solar cell material because it has high optical absorption, low cost, and is earth-abundant. However, previously reported iron pyrite solar cells showed poor photovoltaic characteristics. Here, we have numerically simulated its photovoltaic characteristics and band structures by utilizing a two-dimensional (2D) device simulator, ATLAS, to evaluate the effects of an inversion layer at the surface and a high density of deep donor defect states in the bulk. We found that previous device structures did not consider the inversion layer at the surface region of iron pyrite, which made it difficult to obtain the conversion efficiency. Therefore, we remodeled the device structure and suggested that removing the inversion layer and reducing the density of deep donor defect states would lead to a high conversion efficiency of iron pyrite solar cells.

  15. Size-Dependent Specific Surface Area of Nanoporous Film Assembled by Core-Shell Iron Nanoclusters

    Directory of Open Access Journals (Sweden)

    Jiji Antony

    2006-01-01

    Full Text Available Nanoporous films of core-shell iron nanoclusters have improved possibilities for remediation, chemical reactivity rate, and environmentally favorable reaction pathways. Conventional methods often have difficulties to yield stable monodispersed core-shell nanoparticles. We produced core-shell nanoclusters by a cluster source that utilizes combination of Fe target sputtering along with gas aggregations in an inert atmosphere at 7∘C. Sizes of core-shell iron-iron oxide nanoclusters are observed with transmission electron microscopy (TEM. The specific surface areas of the porous films obtained from Brunauer-Emmett-Teller (BET process are size-dependent and compared with the calculated data.

  16. Extraction chromatographic separation of iron from complex liquid samples and the determination of 55Fe

    International Nuclear Information System (INIS)

    Grahek, Z.; Rozmaric Macefat, M.

    2006-01-01

    Iron separation is described from liquid samples with a high concentration of ions that enables simple determination of 55 Fe. One of the described methods consists of iron precipitation from a large volume seawater by sodium hydroxide and/or ammonium carbonate and separation from other elements (Ca, Sr, Cu, Mg, etc.) on a TRU column with 4M HCl or 8M HNO 3 . In the other procedure iron is separated directly from a mixture of seawater samples and HCl on a TRU column. In both methods, the iron recovery is almost 100%. After separation, 55 Fe is determined by counting with a liquid scintillation counter. The binding of Fe and Zn on TEVA, U/TEVA and TRU resins from seawater solutions of HCl and HNO 3 depends on the type of the resin, concentration of acid and other ions. Iron and zinc can be separated from seawater on a U/TEVA column with 2M HCl. (author)

  17. MODELING OF QUALITY FORMATION OF PIG IRON BILLET SURFACE AT WIRE BRUSH MILLING

    Directory of Open Access Journals (Sweden)

    I. L. Barshaj

    2009-01-01

    Full Text Available Formation of topography, geometrical structure and micro-hardness of pig iron billet surface is considered in the paper. Mathematical models pertaining to formation of the above-mentioned characteristics of surface quality according to parameters of machining regime have been developed on the basis of the executed investigations.

  18. Effect of Heating Time on Hardness Properties of Laser Clad Gray Cast Iron Surface

    Science.gov (United States)

    Norhafzan, B.; Aqida, S. N.; Mifthal, F.; Zulhishamuddin, A. R.; Ismail, I.

    2018-03-01

    This paper presents effect of heating time on cladded gray cast iron. In this study, the effect of heating time on cladded gray cast iron and melted gray cast iron were analysed. The gray cast iron sample were added with mixed Mo-Cr powder using laser cladding technique. The mixed Mo and Cr powder was pre-placed on gray cast iron surface. Modified layer were sectioned using diamond blade cutter and polish using SiC abrasive paper before heated. Sample was heated in furnace for 15, 30 and 45 minutes at 650 °C and cool down in room temperature. Metallographic study was conduct using inverted microscope while surface hardness properties were tested using Wilson hardness test with Vickers scale. Results for metallographic study showed graphite flakes within matrix of pearlite. The surface hardness for modified layer decreased when increased heating time process. These findings are significant to structure stability of laser cladded gray cast iron with different heating times.

  19. X-ray emission spectroscopic determination of iron in a polyurethane encapsulant curing agent

    International Nuclear Information System (INIS)

    Carter, J.M.; Kling, E.N.

    1979-01-01

    Presented is a procedure for determining the iron content in a polyurethane encapsulant curing agent by x-ray emission spectroscopy. Standards were prepared by adding ferric acetyl acetonate to a curing agent of identical composition to that being analyzed, but containing no iron. Results show that x-ray emission spectroscopy is feasible for determination of iron in the 30 to 50 ppM range. This range could probably be extended by the preparation of additional standards. Precision of the method is approximately 1.2 ppM at the 99 percent confidence level

  20. Determination of iron, copper, manganese and zinc in the soils, grapes and wines of the Azores

    Directory of Open Access Journals (Sweden)

    María Teresa Ribeiro de Lima

    2004-06-01

    Full Text Available This paper describes the determination of iron, copper, manganese and zinc in the soils, grapes and wines of the three viticultural regions of the Azores. Iron, copper and zinc were determined by flame atomic absorption spectrometry and manganese by graphite furnace atomic absorption. The concentrations of the four elements differed in soils of the three regions; there was no difference in the concentration in grapes, whereas significant differences were observed for the wines as regards the amounts of iron, manganese and zinc. The concentrations of these four elements in wine correspond with the mean values observed for other European regions.

  1. The determination of iron, chromium, titanium, and tungsten by x-ray-fluorescence spectrometry

    International Nuclear Information System (INIS)

    Austen, C.E.

    1977-01-01

    An accurate and precise method is described for the determination of iron and chromium in chromite, iron and titanium in ilmenite, and tungsten in tungsten ores. Samples are prepared for analysis by fusion with sodium peroxide or sodium tetraborate and leaching of the melt in a solution of tartaric or hydrochloric acid. Matrix correction and calibration are achieved by means of the single-standard calibration method with reference solutions prepared from compounds of the elements determined

  2. Ferromagnetic nuclear resonance investigation of the surface magnetization in iron sheets

    International Nuclear Information System (INIS)

    Varga, L.; Tompa, K.

    1977-09-01

    The role of the domain structure and domain properties in ferromagnetic nuclear resonance (FNR) experiments is reconsidered. Using the FNR signal intensity as a measure of surface domain wall volume, it is found that the behaviour of the surface magnetization differs from that of the bulk magnetization of iron sheets. Namely, a critical field below which the FNR signal remains unchanqed is observed in the surface magnetization. This lag of surface domain wall annihilation is sensitive to the given surface conditions and in particular to the rolling deformation. Considering the small skin depth, FNR as a surface testing method is discussed. (D.P.)

  3. Quantitative proteomic view on secreted, cell surface-associated, and cytoplasmic proteins of the methicillin-resistant human pathogen Staphylococcus aureus under iron-limited conditions.

    Science.gov (United States)

    Hempel, Kristina; Herbst, Florian-Alexander; Moche, Martin; Hecker, Michael; Becher, Dörte

    2011-04-01

    Staphylococcus aureus is capable of colonizing and infecting humans by its arsenal of surface-exposed and secreted proteins. Iron-limited conditions in mammalian body fluids serve as a major environmental signal to bacteria to express virulence determinants. Here we present a comprehensive, gel-free, and GeLC-MS/MS-based quantitative proteome profiling of S. aureus under this infection-relevant situation. (14)N(15)N metabolic labeling and three complementing approaches were combined for relative quantitative analyses of surface-associated proteins. The surface-exposed and secreted proteome profiling approaches comprise trypsin shaving, biotinylation, and precipitation of the supernatant. By analysis of the outer subproteomic and cytoplasmic protein fraction, 1210 proteins could be identified including 221 surface-associated proteins. Thus, access was enabled to 70% of the predicted cell wall-associated proteins, 80% of the predicted sortase substrates, two/thirds of lipoproteins and more than 50% of secreted and cytoplasmic proteins. For iron-deficiency, 158 surface-associated proteins were quantified. Twenty-nine proteins were found in altered amounts showing particularly surface-exposed proteins strongly induced, such as the iron-regulated surface determinant proteins IsdA, IsdB, IsdC and IsdD as well as lipid-anchored iron compound-binding proteins. The work presents a crucial subject for understanding S. aureus pathophysiology by the use of methods that allow quantitative surface proteome profiling.

  4. Effect of orientation of prismatic dislocation loops on interaction with free surfaces in BCC iron

    Science.gov (United States)

    Fikar, Jan; Gröger, Roman; Schäublin, Robin

    2017-12-01

    The prismatic loops appear in metals as a result of high-energy irradiation. Understanding their formation and interaction is important for quantification of irradiation-induced deterioration of mechanical properties. Characterization of dislocation loops in thin foils is commonly made using transmission electron microscopy (TEM), but the results are inevitably influenced by the proximity of free surfaces. The prismatic loops are attracted to free surfaces by image forces. Depending on the type, shape, size, orientation and depth of the loop in the foil, they can escape to the free surface creating denuded loop-free zones and thus invalidating TEM observations. In our previous studies we described a simple general method to determine the critical depth and the critical stress to move prismatic dislocation loops. The critical depths can be further used to correct measurements of the loop density by TEM. Here, we use this procedure to compare 〈100〉 loops and 1/2 〈111〉 loops in body-centered cubic (BCC) iron. The influences of the interatomic potential and the loop orientation are studied in detail. The difference between interstitial and vacancy type loop is also investigated.

  5. New surface radiolabeling schemes of super paramagnetic iron oxide nanoparticles (SPIONs) for biodistribution studies†

    Science.gov (United States)

    Nallathamby, Prakash D.; Mortensen, Ninell P.; Palko, Heather A.; Malfatti, Mike; Smith, Catherine; Sonnett, James; Doktycz, Mitchel J.; Gu, Baohua; Roeder, Ryan K.; Wang, Wei; Retterer, Scott T.

    2016-01-01

    Nanomaterial based drug delivery systems allow for the independent tuning of the surface chemical and physical properties that affect their biodistribution in vivo and the therapeutic payloads that they are intended to deliver. Additionally, the added therapeutic and diagnostic value of their inherent material properties often provides extra functionality. Iron based nanomaterials with their magnetic properties and easily tailorable surface chemistry are of particular interest as model systems. In this study the core radius of the iron oxide nanoparticles (NPs) was 14.08 ± 3.92 nm while the hydrodynamic radius of the NPs, as determined by Dynamic Light Scattering (DLS), was between 90–110 nm. In this study, different approaches were explored to create radiolabeled NPs that are stable in solution. The NPs were functionalized with polycarboxylate or polyamine surface functional groups. Polycarboxylate functionalized NPs had a zeta potential of –35 mV and polyamine functionalized NPs had a zeta potential of +40 mV. The polycarboxylate functionalized NPs were chosen for in vivo biodistribution studies and hence were radiolabeled with 14C, with a final activity of 0.097 nCi mg–1 of NPs. In chronic studies, the biodistribution profile is tracked using low-level radiolabeled proxies of the nanoparticles of interest. Conventionally, these radiolabeled proxies are chemically similar but not chemically identical to the non-radiolabeled NPs of interest. This study is novel as different approaches were explored to create radiolabeled NPs that are stable, possess a hydrodynamic radius of <100 nm and most importantly they exhibit an identical surface chemical functionality as their non-radiolabeled counterparts. Identical chemical functionality of the radiolabeled probes to the non-radiolabeled probes was an important consideration to generate statistically similar biodistribution data sets using multiple imaging and detection techniques. The radiolabeling approach

  6. New surface radiolabeling schemes of super paramagnetic iron oxide nanoparticles (SPIONs) for biodistribution studies.

    Science.gov (United States)

    Nallathamby, Prakash D; Mortensen, Ninell P; Palko, Heather A; Malfatti, Mike; Smith, Catherine; Sonnett, James; Doktycz, Mitchel J; Gu, Baohua; Roeder, Ryan K; Wang, Wei; Retterer, Scott T

    2015-04-21

    Nanomaterial based drug delivery systems allow for the independent tuning of the surface chemical and physical properties that affect their biodistribution in vivo and the therapeutic payloads that they are intended to deliver. Additionally, the added therapeutic and diagnostic value of their inherent material properties often provides extra functionality. Iron based nanomaterials with their magnetic properties and easily tailorable surface chemistry are of particular interest as model systems. In this study the core radius of the iron oxide nanoparticles (NPs) was 14.08 ± 3.92 nm while the hydrodynamic radius of the NPs, as determined by Dynamic Light Scattering (DLS), was between 90-110 nm. In this study, different approaches were explored to create radiolabeled NPs that are stable in solution. The NPs were functionalized with polycarboxylate or polyamine surface functional groups. Polycarboxylate functionalized NPs had a zeta potential of -35 mV and polyamine functionalized NPs had a zeta potential of +40 mV. The polycarboxylate functionalized NPs were chosen for in vivo biodistribution studies and hence were radiolabeled with (14)C, with a final activity of 0.097 nCi mg(-1) of NPs. In chronic studies, the biodistribution profile is tracked using low level radiolabeled proxies of the nanoparticles of interest. Conventionally, these radiolabeled proxies are chemically similar but not chemically identical to the non-radiolabeled NPs of interest. This study is novel as different approaches were explored to create radiolabeled NPs that are stable, possess a hydrodynamic radius of <100 nm and most importantly they exhibit an identical surface chemical functionality as their non-radiolabeled counterparts. Identical chemical functionality of the radiolabeled probes to the non-radiolabeled probes was an important consideration to generate statistically similar biodistribution data sets using multiple imaging and detection techniques. The radiolabeling approach

  7. Determination of the solubility of neodymium in iron by positron annihilation

    International Nuclear Information System (INIS)

    Yu, W.Y.; Qing, L.N.; Zhuo, T.Z.; Rong, C.X.

    1985-01-01

    The authors have measured the lineshape parameters and lifetimes of positron annihilation in eleven samples of iron containing various concentration of Nd between 0 and 0.87 wt. %, which have been heat-treated at two different temperatures successively. According to the abrupt increase, for the two conditions of heat-treatment the solubility of Nd in iron is interpreted to be 0.082 wt. % and 0.088 wt. % respectively. Using positron annihilation technique for determining the solubility of Nd in iron appears to be more sensitive and accurate than metallography method and X-ray diffraction analysis

  8. Determination of iron content in whole blood in different mouse strains using a portable XRFS spectrometer

    International Nuclear Information System (INIS)

    Zamboni, C.B.; Metairon, Sabrina; Suzuki, M.F.; Bahovschi, Vanessa; Rizzutto, M.A.

    2016-01-01

    Iron has an important role in blood as an indicator of a great number of anomalies. Anemia due to iron-deficiency in the world is a public health problem in all ages and socioeconomic levels. Nowadays, Brazil's pharmaceutical companies are testing iron compounds to reduce the costs of those new drugs. In this study, Energy Dispersive X-Ray Fluorescence Technique was applied to determine Fe concentrations in blood samples of different mice strains using a Portable XRF Spectrometer. These data may help researchers choose the convenient mice strain that best meets its medical investigation, reducing costs and optimizing their researches. (author)

  9. Analytical applications of condensed phosphoric acid-I Determination of ferrous and total iron in iron ores after decomposition with condensed phosphoric acid.

    Science.gov (United States)

    Mizoguchi, T; Ishii, H

    1978-06-01

    A simple method is described for the determination of ferrous and total iron in iron ores. Iron ores are dissolved by condensed phosphoric acid (CPA) very rapidly without any tedious and time-consuming manipulations such as elimination of silica and filtration. Under the proposed conditions (amount of sample 100 mg, amount of CPA added 10 g, heating temperature 290 degrees , heating time 30 min), magnetite, limonite and hematite are completely dissolved. The iron content can be determined in the presence of condensed phosphoric acid by titration with dichromate solution, if a slight modification is made. The total iron in iron ores, determined by the present method, is in agreement with that found by the JIS method. The ferrous iron in iron ores can be determined by dissolving the samples with CPA in a nitrogen atmosphere and titrating with dichromate solution. Chelatometric titration of iron after solvent extraction with MIBK from solutions prepared by use of CPA is found to be accurate for samples such as pyrite cinder. The ability of CPA to dissolve various materials has been investigated.

  10. The role of SO{sub 4}{sup 2−} surface distribution in arsenic removal by iron oxy-hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Tresintsi, S. [Analytical Chemistry Laboratory, Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Simeonidis, K., E-mail: ksime@physics.auth.gr [Analytical Chemistry Laboratory, Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Department of Mechanical Engineering, University of Thessaly, 38334 Volos (Greece); Pliatsikas, N.; Vourlias, G.; Patsalas, P. [Laboratory of Applied Physics, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Mitrakas, M. [Analytical Chemistry Laboratory, Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2014-05-01

    This study investigates the contribution of chemisorbed SO{sub 4}{sup 2−} in improving arsenic removal properties of iron oxy-hydroxides through an ion-exchange mechanism. An analytical methodology was developed for the accurate quantification of sulfate ion (SO{sub 4}{sup 2−}) distribution onto the surface and structural compartments of iron oxy-hydroxides synthesized by FeSO{sub 4} precipitation. The procedure is based on the sequential determination of SO{sub 4}{sup 2−} presence in the diffuse and Stern layers, and the structure of these materials as defined by the sulfate-rich environments during the reaction and the variation in acidity (pH 3–12). Physically sorbed SO{sub 4}{sup 2−}, extracted in distilled water, and physically/chemically adsorbed ions on the oxy-hydroxide's surface leached by a 5 mM NaOH solution, were determined using ion chromatography. Total sulfate content was gravimetrically measured by precipitation as BaSO{sub 4}. To validate the suggested method, results were verified by X-ray photoelectron and Fourier-transformed infrared spectroscopy. Results showed that low precipitation pH-values favor the incorporation of sulfate ions into the structure and the inner double layer, while under alkaline conditions ions shift to the diffuse layer. - Graphical abstract: An analytical methodology for the accurate quantification of sulfate ions (SO{sub 4}{sup 2−}) distribution onto the diffuse layer, the Stern layer and the structure of iron oxy-hydroxides used as arsenic removal agents. - Highlights: • Quantification of sulfate ions presence in FeOOH surface compartments. • Preparation pH defines the distribution of sulfates. • XPS and FTIR verify the presence of SO{sub 4}{sup 2−} in the structure, the Stern layer the diffuse layer of FeOOH. • Chemically adsorbed sulfates control the arsenic removal efficiency of iron oxyhydroxides.

  11. Liquid-Liquid Extraction and Determination of Trace Elements in Iron Minerals by Atomic Absorption Spectrometry

    International Nuclear Information System (INIS)

    Taseska, Milena; Stafilov, Trajche; Makreski, Petre; Jacimovic, Radojko; Jovanovski, Gligor

    2006-01-01

    Various trace elements (cadmium, chromium, cobalt, nickel, manganese) in some iron minerals were determined by flame (FAAS) and electrothermal atomic absorption spectrometry (ETAAS). The studied minerals were chalcopyrite (CuFeS 2 ), hematite (Fe 2 O 3 ) and pyrite (FeS 2 ). To avoid the interference of iron, a method for liquid-liquid extraction of iron and determination of investigated elements in the inorganic phase was proposed. Iron was extracted by diisopropyl ether in hydrochloride acid solution and the extraction method was optimized. Some parameters were obtained to be significantly important: Fe mass in the sample should not exceed 0.3 g, the optimal concentration of HCI should be 7.8 mol 1 -1 and ratio of the inorganic and organic phase should be 1: 1. The procedure was verified by the method of standard additions and by its applications to reference standard samples. The investigated minerals originate from various mines in the Republic of Macedonia. (Author)

  12. Iron -chromium alloys and free surfaces: from ab initio calculations to thermodynamic modeling

    International Nuclear Information System (INIS)

    Levesque, M.

    2010-11-01

    Ferritic steels possibly strengthened by oxide dispersion are candidates as structural materials for generation IV and fusion nuclear reactors. Their use is limited by incomplete knowledge of the iron-chromium phase diagram at low temperatures and of the phenomena inducing preferential segregation of one element at grain boundaries or at surfaces. In this context, this work contributes to the multi-scale study of the model iron-chromium alloy and their free surfaces by numerical simulations. This study begins with ab initio calculations of properties related to the mixture of atoms of iron and chromium. We highlight complex dependency of the magnetic moments of the chromium atoms on their local chemical environment. Surface properties are also proving sensitive to magnetism. This is the case of impurity segregation of chromium in iron and of their interactions near the surface. In a second step, we construct a simple energy model for high numerical efficiency. It is based on pair interactions on a rigid lattice to which are given local chemical environment and temperature dependencies. With this model, we reproduce the ab initio results at zero temperature and experimental results at high temperature. We also deduce the solubility limits at all intermediate temperatures with mean field approximations that we compare to Monte Carlo simulations. The last step of our work is to introduce free surfaces in our model. We then study the effect of ab initio calculated bulk and surface properties on surface segregation.Finally, we calculate segregation isotherms. We therefore propose an evolution model of surface composition of iron-chromium alloys as a function of bulk composition. which are given local chemical environment and temperature dependencies. With this model, we reproduce the ab initio results at zero temperature and experimental results at high temperature. We also deduce the solubility limits at all intermediate temperatures with mean field approximations that

  13. Studies of Actinides Reduction on Iron Surfaces by Means of Resonant Inelastic X-ray Scattering

    International Nuclear Information System (INIS)

    Kvashnina, K.O.; Butorin, S.M.; Shuh, D.K.; Ollila, K.; Soroka, I.; Guo, J.-H.; Werme, L.; Nordgren, J.

    2006-01-01

    The interaction of actinides with corroded iron surfaces was studied using resonant inelastic x-ray scattering (RIXS) spectroscopy at actinide 5d edges. RIXS profiles, corresponding to the f-f excitations are found to be very sensitive to the chemical states of actinides in different systems. Our results clearly indicate that U(VI) (as soluble uranyl ion) was reduced to U(IV) in the form of relatively insoluble uranium species, indicating that the iron presence significantly affects the mobility of actinides, creating reducing conditions. Also Np(V) and Pu (VI) in the ground water solution were getting reduced by the iron surface to Np(IV) and Pu (IV) respectively. Studying the reduction of actinides compounds will have an important process controlling the environmental behavior. Using RIXS we have shown that actinides, formed by radiolysis of water in the disposal canister, are likely to be reduced on the inset corrosion products and prevent release from the canister

  14. Rapid collection of iron hydroxide for determination of Th isotopes in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Okubo, Ayako, E-mail: okubo.ayako@jaea.go.jp [Japan Atomic Energy Agency, Research Group for Analytical Chemistry (Japan); Obata, Hajime, E-mail: obata@aori.u-tokyo.ac.jp [Atmosphere Ocean Research Institute, The University of Tokyo (Japan); Magara, Masaaki, E-mail: magara.masaaki@jaea.go.jp [Japan Atomic Energy Agency, Research Group for Analytical Chemistry (Japan); Kimura, Takaumi, E-mail: kimura.takaumi@jaea.go.jp [Japan Atomic Energy Agency, Research Group for Analytical Chemistry (Japan); Ogawa, Hiroshi, E-mail: hogawa@aori.u-tokyo.ac.jp [Atmosphere Ocean Research Institute, The University of Tokyo (Japan)

    2013-12-04

    Graphical abstract: -- Highlights: •DIAION CR-20 chelating resin has successfully collected iron-hydroxide with Th isotopes. •Ferric ions in the iron hydroxide were bonded to functional groups of the chelating resin. •The time of preconcentration step was markedly reduced from a few days to 3–4 h. -- Abstract: This work introduces a novel method of recovery of iron hydroxide using a DIAION CR-20 chelating resin column to determine Th isotopes in seawater with a sector field (SF) inductively coupled plasma mass spectrometer (ICP-MS). Thorium isotopes in seawater were co-precipitated with iron hydroxide, and this precipitate was sent to chelating resin column. Ferric ions in the iron hydroxide were bonded to functional groups of the chelating resin directly, resulting in a pH increase of the effluent by release of hydroxide ion from the iron hydroxide. The co-precipitated thorium isotopes were quantitatively collected within the column, which indicated that thorium was retained on the iron hydroxide remaining on the chelating column. The chelating column quantitatively collected {sup 232}Th with iron hydroxide in seawater at flow rates of 20–25 mL min{sup −1}. Based on this flow rate, a 5 L sample was processed within 3–4 h. The >20 h aging of iron hydroxide tends to reduce the recovery of {sup 232}Th. The rapid collection method was successfully applied to the determination of {sup 230}Th and {sup 232}Th in open-ocean seawater samples.

  15. Smears for determinations surface unfixed tritium contamination

    International Nuclear Information System (INIS)

    Postolache, Cristian; Matei, Lidia

    2003-01-01

    The present paper describes a method of obtaining expanded polystyrene with hydrophilized surface smears by radioinduced grafting of acrylic acid. The grafting was carried out by using a 60 Co γ radiation source. The variation of grafting rates as a function of dose range and absorbed dose was established. Grafting radiochemical rates were determined by radiometric methods using acrylic acid labeled with tritium as a grafting agent. The sampling coefficients and the reproducibility were analyzed as a function of the nature of the contaminated surface. (authors)

  16. Modification of the iron mechanical- and corrosion features by ion implantation in surface

    International Nuclear Information System (INIS)

    Baumvol, I.J.R.

    1981-01-01

    The physical mechanisms responsable by the tin ion implantation in the iron surface at moderated doses are studied. Several techniques are used such as alpha-particle Rutherford backscattering, conversion electron Moessbauer spectroscopy and scanning electron microscopy. (L.C.) [pt

  17. Effect of iron on vanadium (001) strained surface magnetism

    Energy Technology Data Exchange (ETDEWEB)

    Elzain, M; Al-Barwani, M; Gismelseed, A; Al-Rawas, A; Yousif, A; Widatallah, H; Bouziane, K; Al-Omari, I, E-mail: elzain@squ.edu.o [Department of Physics, College Of Science, Box 36, Sultan Qaboos University, Al Khod 123 (Oman)

    2010-03-01

    The magnetism of the vanadium (001) surface has been a controversial subject on both theoretical and experiment fronts. Both strongly ferromagnetic and paramagnetic phases were reported. We have used the first principle full-potential linearized-augmented plane waves (FP-LAPW) as implemented in WIEN2k package to study the magnetic properties of strained surfaces of vanadium films as a function of film thickness. We found that for films thicker than about 11 monolayers, the magnetism of the strained surfaces converge to a constant value of about 0.15{mu}{sub B}. Introduction of Fe monolayers and impurities at the centre of the films affects the magnetic structure of thin films but has no influence on the surface magnetism of thicker films. For Fe monolayers positioned at the centre of thick films, the Fe atoms maintain magnetic moment of order 0.86{mu}{sub B}, a quadruple splitting of order -0.3 mm/s and a small negative isomer shift, while an Fe impurity has vanishing hyperfine fields and magnetic moment. In addition we have varied the location of the Fe monolayer and impurity within the V films and found that their position affects the surface magnetism.

  18. The importance of kinetics and redox in the biogeochemical cycling of iron in the surface ocean.

    Directory of Open Access Journals (Sweden)

    Peter L. Croot

    2012-06-01

    Full Text Available It is now well established that Iron (Fe is a limiting element in many regions of the open ocean. Our current understanding of the key processes which control iron distribution in the open ocean have been largely based on thermodynamic measurements performed under the assumption of equilibrium conditions. Using this equilibrium approach, researchers have been able to detect and quantify organic complexing ligands in seawater and examine their role in increasing the overall solubility of iron. Our current knowledge about iron bioavailability to phytoplankton and bacteria is also based heavily on carefully controlled laboratory studies where it is assumed the chemical species are in equilibrium in line with the free ion association model (FIAM and/or its successor the biotic ligand model (BLM. Similarly most field work on Fe biogeochemistry generally consists of a single profile which is in essence a ‘snap-shot’ in time of the system under investigation. However it is well known that the surface ocean is an extremely dynamic environment and it is unlikely if thermodynamic equilibrium between all the iron species present is ever truly achieved. In sunlit waters this is mostly due to the daily passage of the sun across the sky leading to photoredox processes which alter Fe speciation by cycling between redox states and between inorganic and organic species. Episodic deposition events, are also important perturbations to iron cycling as they bring new iron to the system altering the equilibrium between species and phases. Over the last 20 years the mesoscale iron enrichment experiments (e.g. IronEx I /II, SOIREE, EisenEx, SOFeX, EIFeX, SAGE, SEEDS and SERIES I /II and the FeCycle (I/II experiments have provided the first insights into processes altering iron speciation and distribution which occur over temporal scales of days to weeks. Here we utilize new field data collected in the open ocean on the redox and complexation kinetics of iron in the

  19. A spectral X-ray CT simulation study for quantitative determination of iron

    Science.gov (United States)

    Su, Ting; Kaftandjian, Valérie; Duvauchelle, Philippe; Zhu, Yuemin

    2018-06-01

    Iron is an essential element in the human body and disorders in iron such as iron deficiency or overload can cause serious diseases. This paper aims to explore the ability of spectral X-ray CT to quantitatively separate iron from calcium and potassium and to investigate the influence of different acquisition parameters on material decomposition performance. We simulated spectral X-ray CT imaging of a PMMA phantom filled with iron, calcium, and potassium solutions at various concentrations (15-200 mg/cc). Different acquisition parameters were considered, such as the number of energy bins (6, 10, 15, 20, 30, 60) and exposure factor per projection (0.025, 0.1, 1, 10, 100 mA s). Based on the simulation data, we investigated the performance of two regularized material decomposition approaches: projection domain method and image domain method. It was found that the former method discriminated iron from calcium, potassium and water in all cases and tended to benefit from lower number of energy bins for lower exposure factor acquisition. The latter method succeeded in iron determination only when the number of energy bins equals 60, and in this case, the contrast-to-noise ratios of the decomposed iron images are higher than those obtained using the projection domain method. The results demonstrate that both methods are able to discriminate and quantify iron from calcium, potassium and water under certain conditions. Their performances vary with the acquisition parameters of spectral CT. One can use one method or the other to benefit better performance according to the data available.

  20. The determination of aluminum, copper, iron, and lead in glycol formulations by atomic absorption spectroscopy

    Science.gov (United States)

    1977-01-01

    Initial screening tests and the results obtained in developing procedures to determine Al, Cu, Fe, and Pb in glycol formulations are described. Atomic absorption completion was selected for Cu, Fe and Pb, and after comparison with emission spectroscopy, was selected for Al also. Before completion, carbon, iron, and lead are extracted with diethyl dithio carbamate (DDC) into methyl isobutyl ketone (MIBK). Aluminum was also extracted into MIBK using 8-hydroxyquinoline as a chelating agent. As little as 0.02 mg/l carbon and 0.06 mg/l lead or iron may be determined in glycol formulations. As little as 0.3 mg/l aluminum may be determined.

  1. The structure of ultrathin iron films on tungsten single-crystal surfaces

    International Nuclear Information System (INIS)

    Gardiner, T.M.

    1983-01-01

    Ultrathin iron films vapour deposited onto the surface of a cylindrical tungsten single crystal are discussed. Results from work function change, Auger electron spectroscopic and low energy electron diffraction techniques are combined for a comparison of the initial stages of film growth on four low index planes. Advantage is taken of the opportunity to evaporate onto and simultaneously to make measurements on all surface orientations of the zone. (Auth.)

  2. Methods for the shipboard determination of dissolved iron and manganese in samples of sediment interstitial water

    International Nuclear Information System (INIS)

    Hydes, D.J.; Chapman, E.

    1986-01-01

    Iron is extremely unstable in the presence of oxygen. A working atmosphere containing less than 0.2% oxygen is required if iron losses are not to be significant. Iron can be determined with a single addition of reagent, either manually or by a continuous flow procedure using ferrozine. Using a continuous flow procedure with a 5 cm colorimeter cell the method is linear up to 40 μM Fe and the precision is 2%. Manganese can similarly be determined with a single reagent addition using formaldoxime. For the continuous flow procedure with a 5 cm colorimeter cell the method is linear up to 60 μM Mn and the precision is 1%; however, under these conditions a solution containing 100 μm of iron produces an interference equivalent to 4.7 μM of manganese. A two-reagent procedure was developed using EDTA to suppress the iron interference. Using a 5% EDTA solution interference from a solution containing 100 μM of iron was undetectable. (author)

  3. Advances on surface structural determination by LEED

    International Nuclear Information System (INIS)

    Soares, Edmar A; De Carvalho, Vagner E; De Castilho, Caio M C

    2011-01-01

    In the last 40 years, low energy electron diffraction (LEED) has proved to be the most reliable quantitative technique for surface structural determination. In this review, recent developments related to the theory that gives support to LEED structural determination are discussed under a critical analysis of the main theoretical approximation-the muffin-tin calculation. The search methodologies aimed at identifying the best matches between theoretical and experimental intensity versus voltage curves are also considered, with the most recent procedures being reviewed in detail. (topical review)

  4. Correlation between sub-micron surface roughness of iron oxide encrustations and trace element concentrations

    International Nuclear Information System (INIS)

    Fischer, Cornelius; Karius, Volker; Luettge, Andreas

    2009-01-01

    Iron oxide encrustations are formed on black slate surfaces during oxidative weathering of iron sulfide and phosphate bearing, organic matter-rich slates. Synchronously, trace elements are released during ongoing weathering. Laser ablation ICP-MS analyses of a weathered and encrusted slate showed that major portions of the V, Cu, As, Mo, Pb, Th, and U reside in the encrustation. Recently a potential relationship between several micrometer to 500 nm surface topography roughness of such encrustations and its uranium concentration was shown. Based on laser scanning microscopy measurements, the present study shows that this interrelation must be expanded to small submicron-sized half-pores with diameters between 100 nm and 500 nm. We demonstrate that the relationship is not limited to topography variations of a single encrustation in the hand-specimen scale. Surface topography and geochemical analyses of iron oxide encrustations from several locations but from the same geochemical environment and with similar weathering history showed that the concentrations of U, P, Cu, and Zn correlate inversely with the surface roughness parameter F. This parameter represents the total surface area and is - in this case - a proxy for the root-mean square surface roughness Rq. This study substantiates the environmental importance that micrometer- to submicrometer topography variations of fluid-rock interfaces govern the trapping of trace elements.

  5. Correlation between sub-micron surface roughness of iron oxide encrustations and trace element concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Cornelius, E-mail: cornelius@rice.edu [Department of Earth Science, MS-126, Rice University, 6100 Main Street, Houston, TX 77005 (United States); Geowissenschaftliches Zentrum der Universitaet Goettingen, Abt. Sedimentologie and Umweltgeologie, Goldschmidtstr. 3, D-37077 Goettingen (Germany); Karius, Volker [Geowissenschaftliches Zentrum der Universitaet Goettingen, Abt. Sedimentologie and Umweltgeologie, Goldschmidtstr. 3, D-37077 Goettingen (Germany); Luettge, Andreas [Department of Earth Science, MS-126, Rice University, 6100 Main Street, Houston, TX 77005 (United States); Department of Chemistry, Rice University, 6100 Main Street, Houston, TX 77005 (United States)

    2009-08-01

    Iron oxide encrustations are formed on black slate surfaces during oxidative weathering of iron sulfide and phosphate bearing, organic matter-rich slates. Synchronously, trace elements are released during ongoing weathering. Laser ablation ICP-MS analyses of a weathered and encrusted slate showed that major portions of the V, Cu, As, Mo, Pb, Th, and U reside in the encrustation. Recently a potential relationship between several micrometer to 500 nm surface topography roughness of such encrustations and its uranium concentration was shown. Based on laser scanning microscopy measurements, the present study shows that this interrelation must be expanded to small submicron-sized half-pores with diameters between 100 nm and 500 nm. We demonstrate that the relationship is not limited to topography variations of a single encrustation in the hand-specimen scale. Surface topography and geochemical analyses of iron oxide encrustations from several locations but from the same geochemical environment and with similar weathering history showed that the concentrations of U, P, Cu, and Zn correlate inversely with the surface roughness parameter F. This parameter represents the total surface area and is - in this case - a proxy for the root-mean square surface roughness Rq. This study substantiates the environmental importance that micrometer- to submicrometer topography variations of fluid-rock interfaces govern the trapping of trace elements.

  6. A microbial-mineralization approach for syntheses of iron oxides with a high specific surface area.

    Science.gov (United States)

    Yagita, Naoki; Oaki, Yuya; Imai, Hiroaki

    2013-04-02

    Of minerals and microbes: A microbial-mineralization-inspired approach was used to facilitate the syntheses of iron oxides with a high specific surface area, such as 253 m(2)g(-1) for maghemite (γ-Fe(2)O(3)) and 148 m(2)g(-1) for hematite (α-Fe(2)O(3)). These iron oxides can be applied to electrode material of lithium-ion batteries, adsorbents, and catalysts. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. X-ray fluorescence determination of cobalt in iron-manganese oceanic concretions

    International Nuclear Information System (INIS)

    Ivanenko, V.V.; Kustov, V.N.; Metelev, A.Yu.; Rakita, K.A.

    1989-01-01

    A method was developed for resolution of weak analytical lines for elements determined by radionuclide-excited X-ray fluorescence multi-element analysis. The method was used aboart for determining cobalt and some other commercially valuable elements in iron-manganese concretions of Pacific ocean 109 Cd was used as an ionizing radiation source

  8. HREM of metallized {111} iron oxide nanoparticle surfaces

    International Nuclear Information System (INIS)

    Lovely, G R; Brown, A P; Brydson, R; Kirkland, A I; Meyer, R; Chang, L Y; Jefferson, D A; Falke, M; Bleloch, A

    2006-01-01

    Mixed phase Fe 3 O 4 - γ-Fe 2 O 3 (magnetite-maghemite) nanoparticles have been fabricated by colloidal routes. HR(S)TEM images, taken on both aberration corrected and uncorrected (S)TEMs, and indirect reconstruction of images of the nanoparticles show the presence of {111} facets that terminate with enhanced contrast. This extra contrast is shown to be real and is due to additional octahedral cations occupying the {111} surfaces

  9. Determination of silver in fresh water by atomic absorption spectrometry following flotation preconcentration by iron(III) collectors

    Energy Technology Data Exchange (ETDEWEB)

    Cundeva, K.; Stafilov, T. [Institute of Chemistry, Faculty of Science, St. Cyril and Methodius University, Skopje (Yugoslavia)

    1997-08-01

    Colloid precipitate flotation of silver from fresh water is applied for preconcentration and separation. Optimal conditions using hydrated iron(III) oxide and iron(III) tetramethylenedithiocarbamate as collectors were investigated. Various factors affecting the silver recovery, including collector mass, nature of the supporting electrolyte, pH of the working medium, electrokinetic potential of the collector particle surfaces, type of surfactant, induction time etc., were checked. Within the optimal pH range (5.5-6.5) silver was separated quantitatively (94.9- 100.0%) with 30 mg Fe(III) as collector. The content of silver was determined by electrothermal atomic absorption spectrometry and compared to that from inductively coupled plasma-atomic emission spectrometry. The detection limit of silver by the method described is 0.01 {mu}g/L. (orig.) With 2 figs., 3 tabs.

  10. In situ iron-57 Moessbauer spectroscopic investigations of the effect of titania surface area on the reducibility of titania-supported iron oxide

    International Nuclear Information System (INIS)

    Berry, F.J.; Du Hongzhang

    1990-01-01

    Iron-57 Moessbauer spectroscopy has been used to monitor the reducibility in hydrogen of iron oxides supported on titania of differing surface areas. The results show that although Fe 3+ in the iron oxide supported on low surface area titania (11 m 2 g -1 ) is not amenable to facile reduction at low temperatures, complete reduction to metallic iron is achieved by treatment at 600deg C. The data also show that the extent of reduction at elevated temperatures exceeds that which is obtained on similar silica- and alumina-supported systems. Fe 3+ in iron oxide supported on higher surface area titania (50 m 2 g -1 and 240 m 2 g -1 ) is partially reduced in hydrogen at 235deg C to Fe 2+ but fails to attain complete reduction to the metallic state following treatment at 600deg C. The results are related to the different dispersions of iron oxide which can be attained on titania of differing surface area and the consequent interactions between the support and the supported phases. (orig.)

  11. Multisensor system for determination of iron(II), iron(III) and uranium(VI) in complex solutions

    International Nuclear Information System (INIS)

    Legin, A.V.; Seleznev, B.L.; Rudnitskaya, A.M.; Vlasov, Yu.G.

    1998-01-01

    The aim of the present paper is the development and analytical evaluation of a multisensor system for determination of low content of iron(II), iron(III) and uranium(VI) in complex aqueous media. Sensor array included sensors on the basis of chalcogenide vitreous materials with redox and ionic cross-sensitivities, crystalline silver sulphide electrode, noble metal electrodes Pt, Au, Ag and redox sensor on the basis of oxide glass. Potentiometric measurements have been taken in a conventional electrochemical cell vs. a standard Ag/AgCl reference electrode. All measurements have been taken at room temperature. Calibration solutions contained UO 2 (NO 3 ) 2 in concentration range 10 -6 -1,610 -5 mol/L, K 3 Fe(CN) 6 and K 4 Fe(CN) 6 or FeSO 4 (NH 4 ) 2 SO 4 and FeCl 3 , with the ratio of Fe(II)/Fe(III) concentration from 100:1 to 1:100, the total concentration of Fe was 10 -4 and 10 -5 mol/L. All solutions have been made on the background electrolyte of calcium and magnesium chlorides and sulphates with the fixed content of 5-27 mmol/L of each component which is a typical one for groundwater or mining water. Sensor potentials have been processed by a back-propagation artificial neural net. Average error of determination of Fe(II) and Fe(III) is about 20 %, of uranium(VI) - 40 %. It was found that sensitivity of the sensor array to iron and uranium is irrespective of the chemical form of these species

  12. Atomic emission spectroscopic investigations for determining depth profiles at boride layers on iron materials

    International Nuclear Information System (INIS)

    Danzer, K.; Marx, G.

    1980-01-01

    A combination of atomic emission spectroscopic surface analysis and mechanical removement of defined surface areas in layers by grinding yields information about the depth distribution of boron in iron. In addition, the evaluation with the aid of the two-dimensional variance analysis leads to statements on the homogeneous distribution within individual layers at different depth. The results obtained in this way are in agreement with those of other methods

  13. Influence of redox condition in iron, silicon and hydrogen contents of leached glass surface

    International Nuclear Information System (INIS)

    Manara, A.; Lanza, F.; Della Mea, G.; Rossi, C.; Salvagno, G.

    1984-01-01

    Surface analysis has been conducted on samples leached in a Sochlet apparatus at 100 0 C in the presence and in the absence of air. The XPS technique was applied to analyze the content of iron and silicon while the nuclear reaction method was utilized to analyze the content of hydrogen. Samples leached in argon atmosphere have shown a smaller content of iron and silicon with respect to the samples leached in air atmosphere. The H concentration has shown the same behavior. The results are discussed in terms of possible formation of iron compounds in the different redox condition and of their different stabilities and in terms of their efficiency in reducing exchange between Na + and H + ions. 11 references, 3 figures, 1 table

  14. Efficient MRI labeling of endothelial progenitor cells: design of thiolated surface stabilized superparamagnetic iron oxide nanoparticles.

    Science.gov (United States)

    Shahnaz, Gul; Kremser, Christian; Reinisch, Andreas; Vetter, Anja; Laffleur, Flavia; Rahmat, Deni; Iqbal, Javed; Dünnhaupt, Sarah; Salvenmoser, Willi; Tessadri, Richard; Griesser, Ulrich; Bernkop-Schnürch, Andreas

    2013-11-01

    The aim of this study was to design thiolated surface stabilized superparamagnetic iron oxide nanoparticles (TSS-SPIONs) for efficient internalization with high MRI sensitivity. TSS-SPIONs were developed by chelation between thiolated chitosan-thioglycolic acid (chitosan-TGA) hydrogel and iron ions (Fe(2+)/Fe(3+)). Likely, unmodified chitosan hydrogel SPIONs (UC-SPIONs) and uncoated SPIONs were used as control. Moreover, TSS-SPIONs were investigated regarding to their iron core size, hydrodynamic diameter, zeta potential, iron contents, molar relaxivities (r1 and r2), and cellular internalization. TSS-SPIONs demonstrated an iron oxide core diameter (crystallite size by XRD) of 3.1 ± 0.02 nm, a hydrodynamic diameter of 94 ± 20 nm, a zeta potential of +21 ± 5 mV, and an iron content of 3.6 ± 0.9 mg/mL. In addition, internalization of TSS-SPIONs into human endothelial progenitor cells (EPC) from umbilical cord blood was more than threefold and 17-fold higher in contrast to UC-SPIONs and SPIONs, respectively. With twofold lower incubation iron concentration of TSS-SPIONs, more than threefold higher internalization was achieved as compared to Resovist®. Also, cell viability of more than 90% was observed in the presence of TSS-SPIONs after 24h. The molar MR relaxivities (r2) value at 1.5 T was threefold higher than that of Resovist® and demonstrated that TSS-SPIONs have the potential as very effective T2 contrast-enhancement agent. According to these findings, TSS-SPIONs with efficient internalization, lower cytotoxicity, and high MRI sensitivity seem to be promising for cell tracking. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Iron oxide and hydroxide precipitation from ferrous solutions and its relevance to Martian surface mineralogy

    Science.gov (United States)

    Posey-Dowty, J.; Moskowitz, B.; Crerar, D.; Hargraves, R.; Tanenbaum, L.

    1986-01-01

    Experiments were performed to examine if the ubiquitousness of a weak magnetic component in all Martian surface fines tested with the Viking Landers can be attributed to ferric iron precipitation in aqueous solution under oxidizing conditions at neutral pH. Ferrous solutions were mixed in deionized water and various minerals were added to separate liquid samples. The iron-bearing additives included hematite, goethite, magnetite, maghemite, lepidocrocite and potassium bromide blank at varying concentrations. IR spectroscopic scans were made to identify any precipitates resulting from bubbling oxygen throughout the solutions; the magnetic properties of the precipitates were also examined. The data indicated that the lepidocrocite may have been preferentially precipitated, then aged to maghemite. The process would account for the presumed thin residue of maghemite on the present Martian surface, long after abundant liquid water on the Martian surface vanished.

  16. Iron oxide and hydroxide precipitation from ferrous solutions and its relevance to Martian surface mineralogy

    International Nuclear Information System (INIS)

    Posey-Dowty, J.; Moskowitz, B.; Crerar, D.; Hargraves, R.; Tanenbaum, L.

    1986-01-01

    Experiments were performed to examine if the ubiquitousness of a weak magnetic component in all Martian surface fines tested with the Viking Landers can be attributed to ferric iron precipitation in aqueous solution under oxidizing conditions at neutral pH. Ferrous solutions were mixed in deionized water and various minerals were added to separate liquid samples. The iron-bearing additives included hematite, goethite, magnetite, maghemite, lepidocrocite and potassium bromide blank at varying concentrations. IR spectroscopic scans were made to identify any precipitates resulting from bubbling oxygen throughout the solutions; the magnetic properties of the precipitates were also examined. The data indicated that the lepidocrocite may have been preferentially precipitated, then aged to maghemite. The process would account for the presumed thin residue of maghemite on the present Martian surface, long after abundant liquid water on the Martian surface vanished. 40 references

  17. Spectrophotometric determination of phosphorus in iron alloys employing a flow injection system

    OpenAIRE

    Gervasio,Ana P. G.; Miranda,Carlos E. S.; Luca,Gilmara C.; Tumang,Cristiane A.; Campos,Luis F. P.; Reis,Boaventura F.

    2001-01-01

    A flow-injection procedure for spectrophotometric determination of phosphorus in electrolytic iron and iron alloys is proposed. The method is based on the ammonium molybdate reaction followed by stannous chloride reduction in acidic medium. In order to circumvent the severe interference caused by the major constituents such as Fe(III) and Cr(III), a mini-column packed with AG50W-X8 resin was coupled to the manifold. A sample throughput of 40 determinations per hour, a dynamical range from P 0...

  18. Particle Surface Hydrophobicity and the Dechlorination of Chloro-Compounds by Iron Sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang-Won, E-mail: spark3@uncc.edu; Kim, Sung-Kuk; Kim, Jeong-Bae; Choi, Sung-Woo [Keimyung University, Department of Environmental Science and Engineering (Korea, Republic of); Inyang, Hilary I. [University of North Carolina at Charlotte, Global Institute for Energy and Environmental Systems (United States); Tokunaga, Shuzo [National Institute of Advanced Industrial Science and Technology (Japan)

    2006-02-15

    Halogenated aliphatic compounds (HACs) can be reduced by iron sulfides in aqueous systems. Generally, the thermodynamics and kinetics of dehalogenation reactions are controlled by the mineralogical and particle surface characteristics of the iron sulfide, the composition of the HAC and reaction conditions such as component concentrations, pH and Eh. In this theoretical and experimental investigation of CCl{sub 4} and C{sub 2}Cl{sub 6} reduction by FeS and FeS{sub 2}, the roles of hydrophobic and hydrophilic sites on the iron sulfides were analyzed. Experimental data obtained through zeta potential measurements, were used along with the Gouy-Chapman model and the simple two-layer surface complexation model to relate iron sulfide surface hydroxyl densities to the degree of HAC dehalogenation. The surface hydroxyl site densities of FeS and FeS{sub 2} were found to be 0.11 sites/nm{sup 2} and 0.21 sites/nm{sup 2}, respectively. During the dehalogenation reaction process, CCl{sub 4} was found to decrease to its first intermediate product CHCl{sub 3} within the first 20 hours followed by a slower process of conversion to CH{sub 2}Cl{sub 2}. The results also show that FeS is less hydrated (more hydrophobic) than FeS{sub 2}. For CCl{sub 4} and C{sub 2}Cl{sub 6}, FeS is a better dehalogenator than FeS{sub 2}. These results imply that particle surface hydrophobicity is a critical factor in surface-mediated dehalogenation of chlorinated compounds.

  19. Iron status and its determinants in a nationally representative sample of pregnant women.

    Science.gov (United States)

    Vandevijvere, Stefanie; Amsalkhir, Sihame; Van Oyen, Herman; Egli, Ines; Ines, Egli; Moreno-Reyes, Rodrigo

    2013-05-01

    Iron-deficiency anemia is associated with adverse neonatal health outcomes. Iron status and its determinants were assessed in a representative sample of Belgian pregnant women. Blood samples were collected and a questionnaire was completed face-to-face. Hemoglobin (Hb) and mean cell volume were measured using a Beckman Coulter Hematology Analyzer and serum ferritin (SF) and transferrin receptor (sTfr) concentrations by immunoassay. In total, 55 obstetric clinics and 1,311 pregnant women were included. Approximately 40% of third-trimester and 6% of first-trimester women had SF levels less than 15 μg/L. Approximately 21% of third-trimester and 4% of first-trimester women had anemia (Hb 8.5 mg/L). The median body iron stores were 8.1 mg/kg among first-trimester women, but only 3.6 mg/kg among third-trimester women. SF levels were significantly positively associated with age and education level, and were higher among nulliparous women and lower among North-African women. sTfr concentrations were significantly negatively associated with age and were lower among smokers, nulliparous women, and women who planned their pregnancy. Despite the fact that two thirds of Belgian pregnant women took iron-containing supplements, iron deficiency and iron-deficiency anemia were frequent in third-trimester women. The World Health Organization regards this as a moderate public health problem. National iron supplementation guidelines are needed in Belgium to optimize iron status during pregnancy. Copyright © 2013 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  20. Size-controlled synthesis of superparamagnetic iron oxide nanoparticles and their surface coating by gold for biomedical applications

    Science.gov (United States)

    Maleki, H.; Simchi, A.; Imani, M.; Costa, B. F. O.

    2012-11-01

    The size mono-dispersity, saturation magnetization, and surface chemistry of magnetic nanoparticles (NPs) are recognized as critical factors for efficient biomedical applications. Here, we performed modified water-in-oil inverse nano-emulsion procedure for preparation of stable colloidal superparamagnetic iron oxide NPs (SPIONs) with high saturation magnetization. To achieve mono-dispersed SPIONs, optimization process was probed on several important factors including molar ratio of iron salts [Fe3+ and Fe2+], the concentration of ammonium hydroxide as reducing agent, and molar ratio of water to surfactant. The biocompatibility of the obtained NPs, at various concentrations, was evaluated via MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay and the results showed that the NPs were non-toxic at concentrations gold (˜4 nm) through chemical reduction of attached gold salts at the surface of the SPIONs. The Fe3O4 core/Au shell particles demonstrate strong plasmon resonance absorption and can be separated from solution using an external magnetic field. Experimental data from both physical and chemical determinations of the changes in particle size, surface plasmon resonance optical band, phase components, core-shell surface composition, and magnetic properties have confirmed the formation of the mono-dispersed core-shell nanostructure.

  1. Complexation equilibria and spectrophotometric determination of iron(III) with 1-amino-4-hydroxyanthraquinone.

    Science.gov (United States)

    Abu-Bakr, M S; Sedaira, H; Hashem, E Y

    1994-10-01

    The complex equilibria of iron(III) with 1-amino-4-hydroxyanthraquinone (AMHA) were studied spectrophotometrically in 40% (v/v) ethanol and an ionic strength of 0.1M (NaClO(4)). The complexation reactions were demonstrated and characterized using graphical logarithmic analysis of the absorbance-pH graphs. A simple, rapid, selective and sensitive method for the spectrophotometric determination of trace amounts of Fe(III) is developed based on the formation of Fe(AMHA) complex at pH 2.5 (lambda(max) = 640 nm, epsilon approximately = 2.1 x 10(4) L. mol(-1) . cm(-1)) in the presence of a large number of foreign ions. Interferences caused by palladium(II) was masked by the addition of cyanide ions. The method has been applied to the determination of iron in some synthetic samples and polymetallic iron ores.

  2. Determination of macro nickel, vanadium and iron in crude oil and residues by derivative spectrophotometry

    International Nuclear Information System (INIS)

    Liu, W.; Wang, L.; Li, X.

    1992-01-01

    In this paper, a new method with derivative spectrophotometry and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol as the chromogenic reagent in buffer solution of different pH developed for determining micro amounts of nickel. Vanadium and iron in crude oil and residues is reported. Forth-, Second- and Third-, Fourth-order derivative spectrophotometry were applied to determine nickel, nickel and vanadium, nickel and iron in crude oil and residues, respectively. The derivative maximums chosen for the measurement were at 556 nm for nickel, 540 nm and 643 nm for nickel and vanadium, 524 nm and 604 nm for nickel and iron. Beer's law is valid for the range 1.0 x 10 -6 to 2.5 x 10 -5 M

  3. Toxicity assessment of silica coated iron oxide nanoparticles and biocompatibility improvement by surface engineering.

    Directory of Open Access Journals (Sweden)

    Maria Ada Malvindi

    Full Text Available We have studied in vitro toxicity of iron oxide nanoparticles (NPs coated with a thin silica shell (Fe3O4/SiO2 NPs on A549 and HeLa cells. We compared bare and surface passivated Fe3O4/SiO2 NPs to evaluate the effects of the coating on the particle stability and toxicity. NPs cytotoxicity was investigated by cell viability, membrane integrity, mitochondrial membrane potential (MMP, reactive oxygen species (ROS assays, and their genotoxicity by comet assay. Our results show that NPs surface passivation reduces the oxidative stress and alteration of iron homeostasis and, consequently, the overall toxicity, despite bare and passivated NPs show similar cell internalization efficiency. We found that the higher toxicity of bare NPs is due to their stronger in-situ degradation, with larger intracellular release of iron ions, as compared to surface passivated NPs. Our results indicate that surface engineering of Fe3O4/SiO2 NPs plays a key role in improving particles stability in biological environments reducing both cytotoxic and genotoxic effects.

  4. Determination of total iron in iron ore by x-ray fluorescence analysis using the Compton effect: comparison with others analytical techniques

    International Nuclear Information System (INIS)

    Castilho, M.V. de; Oliveira, R.C.

    1991-01-01

    Total iron in iron ores is determines by X-ray fluorescence analysis method using the compton effect. The Bragg angle is determined for compton no-coherent scattering related to K alpha of Rhodium. This measurement procedure can be used for best fitting of analytical results in X-ray fluorescence, when compared with others methods used for results corrections. (M.V.M.)

  5. Development of an ELISA approach for the determination of flavodoxin and ferredoxin as markers of iron deficiency in phytoplankton.

    Science.gov (United States)

    Inda, Luis A; Luisa Peleato, M

    2003-06-01

    Quantification of the iron-nutritional status of phytoplankton is of great interest not only for the study of oceans but also for fresh waters. Flavodoxin is a small flavoprotein proposed as a marker for iron deficiency, since it is induced as a consequence of iron deprivation, replacing the iron-sulphur protein ferredoxin. Flavodoxin and ferredoxin have been frequently used as markers for determination of iron deficiency in phytoplankton. Using purified flavodoxin and ferredoxin from Scenedesmus vacuolatus and polyclonal antibodies against both proteins, individual ELISA tests have been developed. The assays have a linear response in the range of 30-600 ng/ml of protein.

  6. Accessible reactive surface area and abiotic redox reactivity of iron oxyhydroxides in acidic brines

    Science.gov (United States)

    Strehlau, Jennifer H.; Toner, Brandy M.; Arnold, William A.; Penn, R. Lee

    2017-01-01

    The reactivity of iron oxyhydroxide nanoparticles in low pH and high ionic strength solutions was quantified to assess abiotic contributions to oxidation-reduction chemistry in acidic brine environments, such as mine groundwater seepage, lakes in Western Australia, and acid mine drainage settings, which are of global interest for their environmental impacts and unique geomicrobiology. Factors expected to influence accessible and reactive surface area, including Fe(II) adsorption and aggregate size, were measured as a function of pH and CaCl2 concentration and related to the kinetics of redox reactions in aqueous suspensions of synthetic goethite (α-FeOOH), akaganeite (β-FeOOH), and ferrihydrite (Fe10O14(OH)2) nanoparticles. Aqueous conditions and iron oxyhydroxides were chosen based on characterization of natural iron-rich mine microbial mats located in Soudan Underground Mine State Park, Minnesota, USA. Quinone species were used as redox sensors because they are well-defined probes and are present in natural organic matter. Fe(II) adsorption to the iron oxyhydroxide mineral surfaces from aqueous solution was measurable only at pH values above 4 and either decreased or was not affected by CaCl2 concentration. Concentrations at or above 0.020 M CaCl2 in acetate buffer (pH 4.5) induced particle aggregation. Assessment of Fe(II) adsorption and particle aggregation in acidic brine suggested that accessible reactive surface area may be limited in acidic brines. This was supported by observations of decreasing benzoquinone reduction rate by adsorbed Fe(II) at high CaCl2 concentration. In contrast, the hydroquinone oxidation rate increased at high CaCl2 concentrations, which may be due to suppressed adsorption of Fe(II) generated by the reaction. Results suggest that iron geochemical cycling in acidic brine environments will be substantially different than for iron oxyhydroxides in low-saline waters with circumneutral pH. These findings have implications for acidic

  7. Microstructure and erosion characteristic of nodular cast iron surface modified by tungsten inert gas

    International Nuclear Information System (INIS)

    Abboud, Jaafar Hadi

    2012-01-01

    Highlights: ► Local surface melting. ► Significant improvement in erosion resistance. ► The ductile behaviour was found. -- Abstract: The surface of nodular cast iron has been melted and rapidly solidified by Tungsten Inert Gas (TIG) process to produce a chilled structure of high hardness and better erosion resistance. Welding currents of magnitude 100, 150, and 200 A at a constant voltage of 72 have been used to melt the surface of nodular cast iron. Microstructural characterization, hardness measurements, and erosion wear tests have been performed on these modified surfaces as well as on the untreated material. Microstructural characterization has shown that surface melting resulted in complete or partial dissolution of the graphite nodules and resolidification of primary austenite dendrites, which undergo further decomposition into ferrite and cementite, and interdendritic of acicular eutectic; their microhardness measured across the melted depth ranged between 600 and 800 Hv. The scale of the dendrites and the interdendritic eutectic became coarser when a higher current is used. The results also indicated that remelting process by TIG improved erosion resistance by three to four times. Eroded surface observations of the as-received and TIG melted samples showed a ductile behavior with a maximum erosion rate at 30°. The fine microstructures obtained by the rapid cooling and the formation of a large amount of eutectic cementite instead of the graphite have contributed greatly to the plastic flow and consequently to the better erosion resistance of the TIG surface melted samples.

  8. The influence of various cooling rates during laser alloying on nodular iron surface layer

    Science.gov (United States)

    Paczkowska, Marta; Makuch, Natalia; Kulka, Michał

    2018-06-01

    The results of research referring to modification of the nodular iron surface layer by laser alloying with cobalt were presented. The aim of this study was to analyze the possibilities of cobalt implementation into the surface layer of nodular iron in various laser heat treatment conditions (by generating different cooling rates of melted surface layer). The modified surface layer of nodular iron was analyzed with OM, SEM, TEM, XRD, EDS and Vickers microhardness tester. The modified surface layer of nodular iron after laser alloying consisted of: the alloyed zone (melted with cobalt), the transition zone and the hardened zone from solid state. The alloyed zone was characterized by higher microstructure homogeneity - in contrast to the transition and the hardened zones. All the alloyed zones contained a dendritic microstructure. Dendrites consisted of martensite needles and retained austenite. Cementite was also detected. It was stated, that due to similar dimension of iron and cobalt atoms, their mutual replacement in the crystal lattice could occur. Thus, formation of phases based on α solution: Co-Fe (44-1433) could not be excluded. Although cobalt should be mostly diluted in solid solutions (because of its content in the alloyed zone), the other newly formed phases as Co (ε-hex.), FeC and cobalt carbides: Co3C, CoC0.25 could be present in the alloyed zones as a result of unique microstructure creation during laser treatment. Pearlite grains were observed in the zone, formed using lower power density of the laser beam and its longer exposition time. Simply, such conditions resulted in the cooling rate which was lower than critical cooling rate. The alloyed zones, produced at a higher cooling rate, were characterized by better microstructure homogeneity. Dendrites were finer in this case. This could result from a greater amount of crystal nuclei appearing at higher cooling rate. Simultaneously, the increased amount of γ-Fe and Fe3C precipitates was expected in

  9. Electrochemical surface nitriding of pure iron by molten salt electrochemical process

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, Hiroyuki; Goto, Takuya; Ito, Yasuhiko

    2004-08-11

    Electrochemical surface nitriding of pure iron was investigated in molten LiCl-KCl-Li{sub 3}N systems at 773 K. An outer compound layer and an inner diffusion layer were obtained by means of potentiostatic electrolysis at 1.00 V (versus Li{sup +}/Li). From XRD and SEM analyses, it was confirmed that the obtained compound layer consisted of {epsilon}-Fe{sub 2-3}N and {gamma}'-Fe{sub 4}N; the free energies of formation of the two nitrides are positive and the equilibrium nitrogen partial pressure of those are of the order of 10{sup 4} atm at 773 K. This result suggests that an apparent nitrogen partial pressure of at least the order of 10{sup 4} atm was imposed by the adsorbed nitrogen atoms (N{sub ads}) formed by anodic oxidation of nitride ion (N{sup 3-}) at the iron electrode surface.

  10. Characterization of Nitride Layers Formed by Nitrogen Ion Implantation into Surface Region of Iron

    International Nuclear Information System (INIS)

    Sudjatmoko; Subki, M. Iyos R.

    2000-01-01

    Ion implantation is a convenient means of modifying the physical and chemical properties of the near-surface region of materials. The nitrogen implantation into pure iron has been performed at room temperature with ion dose of 1.310 17 to 1.310 18 ions/cm 2 and ion energy of 20 to 100 keV. The optimum dose of nitrogen ions implanted into pure iron was around 2.2310 17 ions/cm 2 in order to get the maximum wear resistant. SEM micrographs and EDX show that the nitride layers were found on the surface of substrate. The nitrogen concentration profile was measured using EDX in combination with spot technique, and it can be shown that the depth profile of nitrogen implanted into substrate was nearly Gaussian. (author)

  11. Surface modification of iron oxide nanoparticles and their conjuntion with water soluble polymers for biomedical application

    International Nuclear Information System (INIS)

    Nguyen Thanh Huong; Lam Thi Kieu Giang; Nguyen Thanh Binh; Le Quoc Minh

    2009-01-01

    Superparamagnetic iron oxide nanoparticles (SPION) coated with suitable bio-compatible substances have been used in biomedicine, particularly in magnetic resonance imaging (MRI), tissue engineering, and hyperthermia and drug delivery. In this study, we describe the synthesis of SPION and its surface modification for in-vitro experiments. The particle diameter and structure were estimated by FESEM, TEM, XRD analyses. The saturation magnetization was characterized. SPION with a mean size of 12 nm have been prepared under N 2 atmosphere, with support of natural polymeric starch, by controlling chemical coprecipitation of magnetite phase from aqueous solutions containing suitable salts ratios of Fe 2+ and Fe 3+ . The surface of SPION-nanoparticles was treated with a coordinatable agent for higher dispersion ability in water and remaining the superparamagnetic behavior. The prepared iron oxide nanoparticles were coated with starch, dextran, PEG or MPEG to extend the application potential in the quite different engineering field of nano biomedicine.

  12. Iron carbide on titania surface modified with group VA oxides as Fischer-Tropsch catalysts

    International Nuclear Information System (INIS)

    Wachs, I.E.; Fiato, R.A.; Chersich, C.C.

    1986-01-01

    A catalyst is described comprising iron carbide supported on a surface modified titania wherein the support comprises an oxide of a metal selected form the group consisting of niobium, vanadium, tantalum or mixture thereof supported on the titania wherein at least a portion of the supported oxide of niobium, vanandium, tantalum or mixture is in a non-crystalline form. The amount of the supported oxide ranges from about 0.5 to 25 weight percent metal oxide on the titania support based on the total support composition and the catalyst contains at least about 2 milligrams of iron, calculated as Fe/sub 2/O/sub 3/, per square meter of support surface

  13. A community-wide intercomparison exercise for the determination of dissolved iron in seawater

    NARCIS (Netherlands)

    Bowie, A.R.; Achterberg, E.P.; Croot, P.l.; de Baar, H.J.W.; Laan, P.; Moffett, J.W; Ussher, S.; Worsfold, P.J.

    2006-01-01

    The first large-scale international intercomparison of analytical methods for the determination of dissolved iron in seawater was carried out between October 2000 and December 2002. The exercise was conducted as a rigorously "blind" comparison of 7 analytical techniques by 24 international

  14. Determination of Iron Species by Combination of Solvent Assisted-Dispersive Solid Phase Extraction and Spectrophotometry

    Directory of Open Access Journals (Sweden)

    Zahra Dehghani

    2015-06-01

    Full Text Available A simple, rapid and sensitive solvent assisted-dispersive solid phase extraction method was developed for the extraction of iron(II prior to its spectrophotometric determination. The Fe(II reacted with 2,4,6-tris(2-pyridyl-1,3,5-triazine, neutralized with sodium dodecyl sulfate and extracted onto the fine particles of benzophenone which were formed upon rapid injection of a mixture of benzophenone as the sorbent and ethanol as the disperser solvent into the aqueous solution. After phase separation, the sedimented phase containing the complex was dissolved in ethanol and the analyte concentration was determined by measuring its absorption at 594 nm. Total iron was determined after the reduction of Fe(III to Fe(II with hydroxylamine hydrochloride. Under the optimized conditions, an enhancement factor of 32, the detection limit of 0.16 µg l-1, and the relative standard deviation of 1.9% (n = 6 at 20 µg l-1 concentration level of Fe(II were achieved. The method was successfully applied to the determination of iron species in water samples and total iron in infant dry formula milk, apple, rice, spinach and parsley samples.

  15. Determination of iron in natural and mineral waters by flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    ROLANDAS KAZLAUSKAS

    2004-05-01

    Full Text Available Simple methods for the determination of Fe in natural and mineral waters by flame atomic absorption spectrometry (AAS are suggested. The results of the investigation of selectivity of the proposed AAS method proved that this procedure is not affected by high concentrations of other metals. The calibration graph for iron was linear at levels near the detection limit up to at least 0.10 mg ml-1. For the determination of microamounts of iron in mineral waters, an extraction AAS technique was developed. Iron was retained as Fe-8-oxyquinoline complex and extracted into chloroform. The optimal conditions for the extraction of the iron complex were determined. The AAS method was applied to the determination of Fe in mineral waters and natural waters from different areas of Lithuania. The accuracy of the developed method was sufficient and evaluated in comparison with a photometric method. The obtained results demonstrated that the procedure could be successfully applied for the analysis of water samples with satisfactory accuracy.

  16. Prevalence of anaemia, deficiencies of iron and folic acid and their determinants in Ethiopian women.

    Science.gov (United States)

    Haidar, Jemal

    2010-08-01

    A cross-sectional community-based study with analytic component was conducted among Ethiopian women during June-July 2005 to assess the magnitude of anaemia and deficiencies of iron and folic acid and to compare the factors responsible for anaemia among anaemic and non-anaemic cases. In total, 970 women, aged 15-19 years, were selected systematically for haematological and other important parameters. The overall prevalence of anaemia, iron deficiency, iron-deficiency anaemia, deficiency of folic acid, and parasitic infestations was 30.4%, 50.1%, 18.1%, 31.3%, and 13.7% respectively. Women who had more children aged less than five years but above two years, open-field toilet habits, chronic illnesses, and having intestinal parasites were positively associated with anaemia. Women who had no formal education and who did not use contraceptives were negatively associated with anaemia. The major determinants identified for anaemia were chronic illnesses [adjusted odds ratio (AOR) = 1.1, 95% confidence interval (CI) 1.15-1.55), deficiency of iron (AOR = 0.4, 95% CI 0.35-0.64), and deficiency of folic acid (AOR = 0.5, 95% CI 0.50-0.90). The odds for developing anaemia was 1.1 times more likely among women with chronic illnesses, 60% more likely in the iron-deficient and 40% more likely in the folic acid-deficient than their counterparts. One in every three women had anaemia and deficiency of folic acid while one in every two had iron deficiency, suggesting that deficiencies of both folic acid and iron constitute the major micronutrient deficiencies in Ethiopian women. The risk imposed by anaemia to the health of women ranging from impediment of daily activities and poor pregnancy outcome calls for effective public-health measures, such as improved nutrient supplementation, health education, and timely treatment of illnesses.

  17. X-ray fluorescence diffractionless analyzer for determining light element content in iron ore mixtures

    International Nuclear Information System (INIS)

    Yuksa, L.K.; Kochmola, N.M.; Bondarenko, V.P.; Bogdanov, V.K.

    1986-01-01

    Diffractionless X-ray fluorescence analyzer for detecting calcium oxide and silicon dioxide contents in dry iron ore materials has been developed. The analyzer includes a charging unit, sample-conveying device, spectrometric units for detecting calcium and silicon, computing racks and sample-removing device. Results of calcium oxide and silicon dioxide analyses in iron ore mixtures are presented. Errors are evaluated. It is shown that the analyzer provides high accuracy of one-time determinations, as well as reading constancy for a long time

  18. A method for the determination of ascorbic acid using the iron(II)-pyridine-dimethylglyoxime complex

    International Nuclear Information System (INIS)

    Arya, S. P.; Mahajan, M.

    1998-01-01

    A simple and rapid spectrophotometric method for the determination of ascorbic acid is proposed. Ascorbic acid reduces iron (III) to iron (II) which forms a red colored complex with dimethylglyoxime in the presence of pyridine. The absorbance of the resulting solution is measured at 514 nm and a linear relationship between absorbance and concentration of ascorbic acid is observed up to 14 μg ml -1 . Studies on the interference of substances usually associated with ascorbic acid have been carried out and the applicability of the method has been tested by analysing pharmaceutical preparations of vitamin C [it

  19. Effect of surface charge on the colloidal stability and in vitro uptake of carboxymethyl dextran-coated iron oxide nanoparticles

    International Nuclear Information System (INIS)

    Ayala, Vanessa; Herrera, Adriana P.; Latorre-Esteves, Magda; Torres-Lugo, Madeline; Rinaldi, Carlos

    2013-01-01

    Nanoparticle physicochemical properties such as surface charge are considered to play an important role in cellular uptake and particle–cell interactions. In order to systematically evaluate the role of surface charge on the uptake of iron oxide nanoparticles, we prepared carboxymethyl-substituted dextrans with different degrees of substitution, ranging from 38 to 5 groups per chain, and reacted them using carbodiimide chemistry with amine–silane-coated iron oxide nanoparticles with narrow size distributions in the range of 33–45 nm. Surface charge of carboxymethyl-substituted dextran-coated nanoparticles ranged from −50 to 5 mV as determined by zeta potential measurements, and was dependent on the number of carboxymethyl groups incorporated in the dextran chains. Nanoparticles were incubated with CaCo-2 human colon cancer cells. Nanoparticle–cell interactions were observed by confocal laser scanning microscopy and uptake was quantified by elemental analysis using inductively coupled plasma mass spectroscopy. Mechanisms of internalization were inferred using pharmacological inhibitors for fluid-phase, clathrin-mediated, and caveola-mediated endocytosis. Results showed increased uptake for nanoparticles with greater negative charge. Internalization patterns suggest that uptake of the most negatively charged particles occurs via non-specific interactions

  20. Effect of surface charge on the colloidal stability and in vitro uptake of carboxymethyl dextran-coated iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ayala, Vanessa; Herrera, Adriana P.; Latorre-Esteves, Magda; Torres-Lugo, Madeline [University of Puerto Rico, Department of Chemical Engineering (United States); Rinaldi, Carlos, E-mail: carlos.rinaldi@bme.ufl.edu [University of Florida, J. Crayton Pruitt Family Department of Biomedical Engineering (United States)

    2013-08-15

    Nanoparticle physicochemical properties such as surface charge are considered to play an important role in cellular uptake and particle-cell interactions. In order to systematically evaluate the role of surface charge on the uptake of iron oxide nanoparticles, we prepared carboxymethyl-substituted dextrans with different degrees of substitution, ranging from 38 to 5 groups per chain, and reacted them using carbodiimide chemistry with amine-silane-coated iron oxide nanoparticles with narrow size distributions in the range of 33-45 nm. Surface charge of carboxymethyl-substituted dextran-coated nanoparticles ranged from -50 to 5 mV as determined by zeta potential measurements, and was dependent on the number of carboxymethyl groups incorporated in the dextran chains. Nanoparticles were incubated with CaCo-2 human colon cancer cells. Nanoparticle-cell interactions were observed by confocal laser scanning microscopy and uptake was quantified by elemental analysis using inductively coupled plasma mass spectroscopy. Mechanisms of internalization were inferred using pharmacological inhibitors for fluid-phase, clathrin-mediated, and caveola-mediated endocytosis. Results showed increased uptake for nanoparticles with greater negative charge. Internalization patterns suggest that uptake of the most negatively charged particles occurs via non-specific interactions.

  1. Determinants of iron accumulation in deep grey matter of multiple sclerosis patients

    DEFF Research Database (Denmark)

    Ropele, Stefan; Kilsdonk, Iris D; Wattjes, Mike P

    2014-01-01

    BACKGROUND: Iron accumulation in deep grey matter (GM) structures is a consistent finding in multiple sclerosis (MS) patients. This study focused on the identification of independent determinants of iron accumulation using R2* mapping. SUBJECTS AND METHODS: Ninety-seven MS patients and 81 healthy...... controls were included in this multicentre study. R2* mapping was performed on 3T MRI systems. R2*in deep GM was corrected for age and was related to disease duration, disability, T2 lesion load and brain volume. RESULTS: Compared to controls, R2* was increased in all deep GM regions of MS patients except...... and the red nucleus. In lesions, R2* was inversely correlated with disease duration and higher total lesion load. CONCLUSION: Iron accumulation in deep GM of MS patients is most strongly and independently associated with duration and severity of the disease. Additional associations between cortical GM atrophy...

  2. Direct voltammetric determination of redox-active iron in carbon nanotubes.

    Science.gov (United States)

    Teo, Wei Zhe; Pumera, Martin

    2014-12-01

    With the advances in nanotechnology over the past decade, consumer products are increasingly being incorporated with carbon nanotubes (CNTs). As the harmful effects of CNTs are suggested to be primarily due to the bioavailable amounts of metallic impurities, it is vital to detect and quantify these species using sensitive and facile methods. Therefore, in this study, we investigated the possibility of quantifying the amount of redox-available iron-containing impurities in CNTs with voltammetric techniques such as cyclic voltammetry. We examined the electrochemistry of Fe3 O4 nanoparticles in phosphate buffer solution and discovered that its electrochemical behavior could be affected by pH of the electrolyte. By utilizing the unique redox reaction between the iron and phosphate species, the redox available iron content in CNTs was determined successfully using voltammetry. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. [Determination of Total Iron and Fe2+ in Basalt].

    Science.gov (United States)

    Liu, Jian-xun; Chen, Mei-rong; Jian, Zheng-guo; Wu, Gang; Wu, Zhi-shen

    2015-08-01

    Basalt is the raw material of basalt fiber. The content of FeO and Fe2O3 has a great impact on the properties of basalt fibers. ICP-OES and dichromate method were used to test total Fe and Fe(2+) in basalt. Suitable instrument parameters and analysis lines of Fe were chosen for ICP-OES. The relative standard deviation (RSD) of ICP-OES is 2.2%, and the recovery is in the range of 98%~101%. The method shows simple, rapid and highly accurate for determination of total Fe and Fe(2+) in basalt. The RSD of ICP-OES and dichromate method is 0.42% and 1.4%, respectively.

  4. Cell tagging with clinically approved iron oxides: feasibility and effect of lipofection, particle size, and surface coating on labeling efficiency.

    Science.gov (United States)

    Matuszewski, Lars; Persigehl, Thorsten; Wall, Alexander; Schwindt, Wolfram; Tombach, Bernd; Fobker, Manfred; Poremba, Christopher; Ebert, Wolfgang; Heindel, Walter; Bremer, Christoph

    2005-04-01

    To evaluate the effect of lipofection, particle size, and surface coating on labeling efficiency of mammalian cells with superparamagnetic iron oxides (SPIOs). Institutional Review Board approval was not required. Different human cell lines (lung and breast cancer, fibrosarcoma, leukocytes) were tagged by using carboxydextran-coated SPIOs of various hydrodynamic diameters (17-65 nm) and a dextran-coated iron oxide (150 nm). Cells were incubated with increasing concentrations of iron (0.01-1.00 mg of iron [Fe] per milliliter), including or excluding a transfection medium (TM). Cellular iron uptake was analyzed qualitatively at light and electron microscopy and was quantified at atomic emission spectroscopy. Cell visibility was assessed with gradient- and spin-echo magnetic resonance (MR) imaging. Effects of iron concentration in the medium and of lipofection on cellular SPIO uptake were analyzed with analysis of variance and two-tailed Student t test, respectively. Iron oxide uptake increased in a dose-dependent manner with higher iron concentrations in the medium. The TM significantly increased the iron load of cells (up to 2.6-fold, P .05). As few as 10 000 cells could be detected with clinically available MR techniques by using this approach. Lipofection-based cell tagging is a simple method for efficient cell labeling with clinically approved iron oxide-based contrast agents. Large particle size and carboxydextran coating are preferable for cell tagging with endocytosis- and lipofection-based methods. (c) RSNA, 2005.

  5. A Course at the Master Level Demonstrating Quality Assurance by Spectrophotometric Determination of Iron in two experiments

    DEFF Research Database (Denmark)

    In two experiments, the first a batch determination of iron, and the second determination of iron by flow injection analysis, the students perform a number of repetitions. The measurements were repeated until it became possible to estimate which one of the two methods exhibited the better perform...

  6. On Degradation of Cast Iron Surface-Protective Paint Coat Joint

    Directory of Open Access Journals (Sweden)

    Tupaj M.

    2016-09-01

    Full Text Available The paper is a presentation of a study on issues concerning degradation of protective paint coat having an adverse impact on aesthetic qualities of thin-walled cast-iron castings fabricated in furan resin sand. Microscopic examination and microanalyses of chemistry indicated that under the coat of paint covering the surface of a thin-walled casting, layers of oxides could be found presence of which can be most probably attributed to careless cleaning of the casting surface before the paint application process, as well as corrosion pits evidencing existence of damp residues under the paint layers contributing to creation of corrosion micro-cells

  7. Modifications of mechanical characteristics and iron corrosion by ionic implantation on surface

    International Nuclear Information System (INIS)

    Baumvol, I.J.

    1980-01-01

    Tin ionic implantation on pure iron surface at moderate doses (5x10 15 to 5x10 16 ) Sn + Cu -2 ) has proven to be very efficient in improving the metal characteristics to oxidation and abrasion at high temperature. The abrasion volumetric coefficient K v , is reduced from up to 100 times, and the oxidation tax constant is reduced from up to 10 times. The physical mechanisms responsible for these phenomena are studied using different techniques of surface analysis; as Rutherford backscattering of alpha particles, Moessbauer spectroscopy of conversion electrons and sweeping electronic microscopy. (A.C.A.S.) [pt

  8. Perturbed angular correlation study of surface magnetization in iron single crystals

    International Nuclear Information System (INIS)

    Sawicka, B.D.; Sawicki, J.A.; Pleiter, F.; Waard, H. de

    1983-01-01

    The behaviour of closure domains at the surface of iron single crystals in an external magnetic field was studied by DPAC on samples implanted with 111 In. It is observed that the surface magnetization does not follow that of the bulk. The movement of both the 90 0 and 180 0 walls of the closure domains is blocked up to a certain 'starting' value of the external field that is related to the demagnetization factor of the sample and also depends on the precise orientation of the crystal axes and on the implanted indium dose. (Auth.)

  9. Iron oxidation kinetics and phosphorus immobilization at the groundwater-surface water interface

    Science.gov (United States)

    van der Grift, Bas; Rozemeijer, Joachim; Griffioen, Jasper; van der Velde, Ype

    2014-05-01

    Eutrophication of freshwater environments following diffuse nutrient loads is a widely recognized water quality problem in catchments. Fluxes of non-point P sources to surface waters originate from surface runoff and flow from soil water and groundwater into surface water. The availability of P in surface waters is controlled strongly by biogeochemical nutrient cycling processes at the soil-water interface. The mechanisms and rates of the iron oxidation process with associated binding of phosphate during exfiltration of anaerobic Fe(II) bearing groundwater are among the key unknowns in P retention processes in surface waters in delta areas where the shallow groundwater is typically pH-neutral to slightly acid, anoxic, iron-rich. We developed an experimental field set-up to study the dynamics in Fe(II) oxidation and mechanisms of P immobilization at the groundwater-surface water interface in an agricultural experimental catchment of a small lowland river. We physically separated tube drain effluent from groundwater discharge before it entered a ditch in an agricultural field. The exfiltrating groundwater was captured in in-stream reservoirs constructed in the ditch. Through continuous discharge measurements and weekly water quality sampling of groundwater, tube drain water, exfiltrated groundwater, and ditch water, we quantified Fe(II) oxidation kinetics and P immobilization processes across the seasons. This study showed that seasonal changes in climatic conditions affect the Fe(II) oxidation process. In winter time the dissolved iron concentrations in the in-stream reservoirs reached the levels of the anaerobic groundwater. In summer time, the dissolved iron concentrations of the water in the reservoirs are low, indicating that dissolved Fe(II) is completely oxidized prior to inflow into the reservoirs. Higher discharges, lower temperatures and lower pH of the exfiltrated groundwater in winter compared to summer shifts the location of the redox transition zone

  10. Method for determining the hardness of strain hardening articles of tungsten-nickel-iron alloy

    International Nuclear Information System (INIS)

    Wallace, S.A.

    1984-01-01

    The present invention is directed to a rapid nondestructive method for determining the extent of strain hardening in an article of tungsten-nickel-iron alloy. The method comprises saturating the article with a magnetic field from a permanent magnet, measuring the magnetic flux emanating from the article, comparing the measurements of the magnetic flux emanating from the article with measured magnetic fluxes from similarly shaped standards of the alloy with known amounts of strain hardening to determine the hardness

  11. The determination, by flow-injection analysis, of iron, sulphate, silver and cadmium

    International Nuclear Information System (INIS)

    Jones, E.A.

    1983-01-01

    This report describes the spectrophotometric determination by flow-injection analysis including, where necessary, liquid-liquid extraction of iron with 1,10-phenanthroline; of sulphate by its catalytic effect on the methylthymol blue-zirconium reaction; of silver with bromopyrogallol red and 1,10-phenanthroline; and of cadmium with dithizone. Optimum conditions for each system are established, and sensitivities and ranges of determination are given

  12. Presence, distribution, and diversity of iron-oxidizing bacteria at a landfill leachate-impacted groundwater surface water interface

    DEFF Research Database (Denmark)

    Yu, R.; Gan, P.; Mackay, A.A.

    2010-01-01

    ) were dominated by members of the Bradyrhizobiaceae and Comamonadaceae; clones from the deeper sediments were phylogenetically more diverse, dominated by members of the Rhodocyclaceae. The iron deposition profiles indicated that active iron oxidation occurred only within the near-to-surface GSI......We examined the presence of iron-oxidizing bacteria (IOB) at a groundwater surface water interface (GSI) impacted by reduced groundwater originating as leachate from an upgradient landfill. IOB enrichments and quantifications were obtained, at high vertical resolution, by an iron/oxygen opposing...... site mirrored the IOB distribution. Clone libraries from two separate IOB enrichments indicated a stratified IOB community with clear differences at short vertical distances. Alpha- and Betaproteobacteria were the dominant phylotypes. Clones from the near-surface sediment (1-2 cm below ground surface...

  13. Influence of the surface roughness on the fatigue properties in ausferritic ductile irons (ADI

    Directory of Open Access Journals (Sweden)

    Svenningsson Roger

    2014-06-01

    Full Text Available Heat treatment of cast ductile iron (DI to ausferritic ductile iron (ADI is known to increase fatigue properties. However, the surface roughness of the cast material is also of significant importance. In this investigation, test rods with seven different surface qualities were cast from the same melt i.e. with same chemical composition. The surfaces of the test rods were varied by a number of parameters; grain size of the moulding sand, coated or non-coated mould surfaces, as-cast or machined and polished, shot peened or not. In addition, a reference material in conventional DI was cast and tested. All eight series were subjected to high-cycle fatigue bending tests. The results show that surface defects, such as micro porosity and minor inclusions drastically decrease the fatigue properties. For some ADI materials the stress amplitude limit was actually lower compared to the non-heat treated DI. The machined, polished and shot-peened material demonstrated the best fatigue properties, which is as expected.

  14. Some studies of lead and iron adsorption on the W(100) surface by field emission microscopy

    International Nuclear Information System (INIS)

    Jones, J.P.; Roberts, E.W.

    1978-01-01

    The behaviour of lead and iron adsorbed on the W(100) surface has been studied by probe hole field emission microscopy, field desorption, and by measurement of the total energy distribution (TED) of field-emitted electrons. Lead adsorbed at 300 K which reduces the work function of W(100) can be completely removed at 78 K by field desorption below 3.2 V A -1 and the resulting surface has both the work function and TED, which are characteristic of the clean plane. Condensation at 800 K followed by field desorption, results in a plane surface of work function 4.17 eV and an altered TED. This effect is attributed to the microfacetting, which is observed by LEED. The Swanson peak in the W(100) TED which is removed by submonolayer amounts of lead re-emerges at monolayer coverage when lead adopts the (1 X 1) structure. Such behaviour is consistent with the model proposed by Kar and Soven. A spectral peak observed when lead is adsorbed on the reconstructed W(100) surface is thought to derive for the atomic 1 D state. Adsorption of iron on a W(100) surface reduces phi considerably due to dipole formation and efficiently quenches the Swanson peak. (Auth.)

  15. Evaluation of the effect of sulfate, alkalinity and disinfector on iron release of iron pipe and iron corrosion scale characteristics under water quality changing condition using response surface methodology

    Science.gov (United States)

    Yang, Fan; Shi, Baoyou; Zhang, Weiyu; Guo, Jianbo; Wu, Nana; Liu, Xinyuan

    2018-02-01

    The response surface methodology (RSM), particularly Box-Behnken design model, was used in this study to evaluate the sulfate, alkalinity and free chlorine on iron release of pipe with groundwater supply history and its iron corrosion scale characteristics under water quality changing experiment. The RSM results together with response surface contour plots indicated that the iron release of pipe section reactors was positively related with Larson Ratio and free chlorine. The thin Corrosion scales with groundwater supply history upon collection site contained Fe3O4 (18%), α-FeOOH (64%), FeCO3 (9%), β-FeOOH (8%) and γ-FeOOH (5%), besides their averaged amorphous iron oxide content was 13.6%. After the RSM water quality changing experiment, Fe3O4, amorphous iron oxide and intermediate iron products (FeCO3, Green Rust (GR)) content on scale of Cl2Rs increased, while their α-FeOOH contents decreased and β-FeOOH disappeared. The high iron released Cl2Rs receiving higher LR water (1.40-2.04) contained highest FeCO3 (20%) and amorphous iron oxide (42%), while the low iron release Cl2Rs receiving lower LR water (0.52-0.73) had higher GR(6.5%) and the amorphous iron oxide (23.7%). In high LR water (>0.73), the thin and non-protective corrosion scale containing higher amorphous iron oxide, Fe(II) derived from new produced Fe3O4 or FeCO3 or GR was easy for oxidants and sulfate ions penetration, and had higher iron release. However the same unstable corrosion scale didn’t have much iron release in low LR water (≤0.73). RSM experiment indicated that iron release of these unstable corrosion scales had close relationship with water quality (Larson Ratio and disinfectant). Optimizing the water quality of new source water and using reasonable water purification measures can help to eliminate the red water case.

  16. Evaluation of cutting force and surface roughness in high-speed milling of compacted graphite iron

    Directory of Open Access Journals (Sweden)

    Azlan Suhaimi Mohd

    2017-01-01

    Full Text Available Compacted Graphite Iron, (CGI is known to have outstanding mechanical strength and weight-to-strength ratio as compared to conventional grey cast iron, (CI. The outstanding characteristics of CGI is due to its graphite particle shape, which is presented as compacted vermicular particle. The graphite is interconnected with random orientation and round edges, which results in higher mechanical strength. Whereas, graphite in the CI consists of a smooth-surfaced flakes that easily propagates cracks which results in weaker and brittle properties as compared to CGI. Owing to its improved properties, CGI is considered as the best candidate material in substituting grey cast iron that has been used in engine block applications for years. However, the smooth implementation of replacing CI with CGI has been hindered due to the poor machinability of CGI especially at high cutting speed. The tool life is decreased by 20 times when comparing CGI with CI under the same cutting condition. This study investigates the effect of using cryogenic cooling and minimum quantity lubrication (MQL during high-speed milling of CGI (grade 450. Results showed that, the combination of internal cryogenic cooling and enhanced MQL improved the tool life, cutting force and surface quality as compared to the conventional flood coolant strategy during high-speed milling of CGI.

  17. Dietary Determinants of and Possible Solutions to Iron Deficiency for Young Women Living in Industrialized Countries: A Review

    Directory of Open Access Journals (Sweden)

    Kathryn L. Beck

    2014-09-01

    Full Text Available Iron deficiency is a concern in both developing and developed (industrialized countries; and young women are particularly vulnerable. This review investigates dietary determinants of and possible solutions to iron deficiency in young women living in industrialized countries. Dietary factors including ascorbic acid and an elusive factor in animal protein foods (meat; fish and poultry enhance iron absorption; while phytic acid; soy protein; calcium and polyphenols inhibit iron absorption. However; the effects of these dietary factors on iron absorption do not necessarily translate into an association with iron status and iron stores (serum ferritin concentration. In cross-sectional studies; only meat intake has consistently (positively been associated with higher serum ferritin concentrations. The enhancing effects of ascorbic acid and meat on iron absorption may be negated by the simultaneous consumption of foods and nutrients which are inhibitory. Recent cross-sectional studies have considered the combination and timing of foods consumed; with mixed results. Dietary interventions using a range of focused dietary measures to improve iron status appear to be more effective than dietary approaches that focus on single nutrients or foods. Further research is needed to determine optimal dietary recommendations for both the prevention and treatment of iron deficiency.

  18. Recent progress on magnetic iron oxide nanoparticles: synthesis, surface functional strategies and biomedical applications

    Science.gov (United States)

    Wu, Wei; Wu, Zhaohui; Yu, Taekyung; Jiang, Changzhong; Kim, Woo-Sik

    2015-01-01

    This review focuses on the recent development and various strategies in the preparation, microstructure, and magnetic properties of bare and surface functionalized iron oxide nanoparticles (IONPs); their corresponding biological application was also discussed. In order to implement the practical in vivo or in vitro applications, the IONPs must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of IONPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The new functionalized strategies, problems and major challenges, along with the current directions for the synthesis, surface functionalization and bioapplication of IONPs, are considered. Finally, some future trends and the prospects in these research areas are also discussed. PMID:27877761

  19. Magnetization of individual yeast cells by in situ formation of iron oxide on cell surfaces

    Science.gov (United States)

    Choi, Jinsu; Lee, Hojae; Choi, Insung S.; Yang, Sung Ho

    2017-09-01

    Magnetic functionalization of living cells has intensively been investigated with the aim of various bioapplications such as selective separation, targeting, and localization of the cells by using an external magnetic field. However, the magnetism has not been introduced to individual living cells through the in situ chemical reactions because of harsh conditions required for synthesis of magnetic materials. In this work, magnetic iron oxide was formed on the surface of living cells by optimizing reactions conditions to be mild sufficiently enough to sustain cell viability. Specifically, the reactive LbL strategy led to formation of magnetically responsive yeast cells with iron oxide shells. This facile and direct post-magnetization method would be a useful tool for remote manipulation of living cells with magnetic interactions, which is an important technique for the integration of cell-based circuits and the isolation of cell in microfluidic devices.

  20. Interaction of cysteine and copper ions on the surface of iron: EIS, polarization and XPS study

    International Nuclear Information System (INIS)

    El-Deab, Mohamed S.

    2011-01-01

    Highlights: → The current study demonstrates a comprehensive study for Cysteine + Cu(II) ions as an efficient inhibitor as demonstrated by EIS, XPS and potentiodynamic polarization measurements, in addition to traditional weight loss measurements. → The novelty of the current work originates from the combined use of an eco-friendly compound (i.e., cysteine) with a minute amount of copper ions (in the micro molar range) as a corrosion inhibitor for low carbon steel in acidic medium. To this end, cysteine shows only moderate inhibition ca. 60% for iron which jumps up to more than 95% in the presence of micro molar range of Cu(II) ions. → Cysteine-Cu(II) blends are found superior to benzotriazole (BTAH)-Cu(II) blends in terms of their long-term stability in addition to the avoidance of the use of the well-reported highly toxic BTAH. - Abstract: This study addresses the enhancing effect of copper ions on the inhibition efficiency (IE) of cysteine (an eco-friendly compound) against the corrosion of iron in 0.5 M sulphuric acid. Electrochemical impedance spectroscopy (EIS) data revealed a significant increase in the polarization resistance (R p ) of the iron/solution interface in the presence of cysteine and Cu(II) ions instead of cysteine alone. That is, IE of 95% is obtained in the presence of 5 mM cysteine and 25 μM Cu(II) ions, compared to 66% in absence of Cu(II) ions. Moreover, electrochemical polarization measurements indicate that cysteine and Cu(II) ions blends act as mixed-type inhibitors for the corrosion of iron. The formation of Cu(I)-cysteinate complex and/or cysteine SAM at Cu atop the iron surface (as evident from X-ray photoelectron spectroscopy (XPS)) blocks the underlying iron surface and imparts a pronounced protection against its corrosion. IE of cysteine-Cu(II) blend remains effectively unchanged with immersion time indicating its high stability in the used acidic medium.

  1. Determination of copper and iron in the human aqueous humor by atomic absorption spectrometer with graphite furnace

    International Nuclear Information System (INIS)

    Iqbal, Z.; Mohammad, Z.; Shah, M.T.; Saeed, M.; Imdadullah

    1999-01-01

    The concentration of copper and iron was determined in human aqueous humor using atomic absorption spectrophotometer equipped with graphite furnace. The mean (+- SEM) concentrations of copper (n=16) and iron (n=14) were 0.0234 -+ 0.0045 mu g.ml/sup -1/ and 0.045 -+ 0.0092 mu.ml/sup -1/ respectively. In male and female, the concentrations of copper (p< 0.82) and iron (p<0.38) were not significantly different. (author)

  2. Extraction and atomic absorption spectrophotometric determination of iron and ruthenium by using potassium xanthates

    Energy Technology Data Exchange (ETDEWEB)

    Aihara, M; Kiboku, M [Kinki Univ., Higashi-Osaka, Osaka (Japan)

    1981-06-01

    Potassium xanthates (potassium o-alkyl dithiocarbonate; KRX) react with many metal ions, and so the complex formation with iron (II, III) ion and the extraction of their complexes has been studied to some extent, but those of ruthenium (III) have not been. Iron-xanthate and ruthenium-xanthate complexes can be extracted into methyl isobutyl ketone (MIBK) from weakly acidic solution to weakly alkaline solution. For quantitative extraction of iron (20 ..mu..g/40 ml), KRX concentration should be above 2.0 x 10/sup -2/ mol dm/sup -3/ of KEtX, 1.0 x 10/sup -2/ mol dm/sup -3/ of KPrX, and 5.0 x 10/sup -3/ mol dm/sup -3/ of KBtX and KPeX, and for that of ruthenium (202 ..mu..g/40 ml), it should be above 2.0 x 10/sup -1/ mol dm/sup -3/ of KEtX and KPrX. Formation constant of ruthenium-xanthate complexes is presumed to be small. A 100-fold excess of Ni(II), Co(II), Cu(II), WO/sub 4//sup 2 -/, PO/sub 4//sup 3 -/, CrO/sub 4//sup 2 -/, and Cr/sub 2/O/sub 7//sup 2 -/ interfered with the determination of iron, however, the interferences are eliminated by adding 5 ml of 0.1 mol dm/sup -3/ ascorbic acid solution. For the determination of ruthenium, a 50-fold excess of Ag(I), Hg(II), Pb(II), Zn(II), Mn(II), Cr(III), and Pt(II), or a 100-fold excess of NO/sub 2//sup -/, S/sub 2/O/sub 3//sup 2 -/, CrO/sub 4//sup 2 -/ and Cr/sub 2/O/sub 7//sup 2 -/, respectively, interfered. The coefficient of variation after each ten runs, ranges from 0.9% to 3.2% in the determination of 10 ..mu..g, 20 ..mu..g, and 30 ..mu..g of iron, and from 1.4% to 4.3% in the determination of 100 ..mu..g, 200 ..mu..g, and 300 ..mu..g of ruthenium. The determination limit in aqueous samples is 0.02 ppm for iron and 0.2 ppm for ruthenium, when the volume ratio of aqueous phase to organic phase (MIBK) is 10:1.

  3. A method for determination of [Fe3+]/[Fe2+] ratio in superparamagnetic iron oxide

    Science.gov (United States)

    Jiang, Changzhao; Yang, Siyu; Gan, Neng; Pan, Hongchun; Liu, Hong

    2017-10-01

    Superparamagnetic iron oxide nanoparticles (SPION), as a kind of nanophase materials, are widely used in biomedical application, such as magnetic resonance imaging (MRI), drug delivery, and magnetic field assisted therapy. The magnetic property of SPION has close connection with its crystal structure, namely it is related to the ratio of Fe3+ and Fe2+ which form the SPION. So a simple way to determine the content of the Fe3+ and Fe2+ is important for researching the property of SPION. This review covers a method for determination of the Fe3+ and Fe2+ ratio in SPION by UV-vis spectrophotometry based the reaction of Fe2+ and 1,10-phenanthroline. The standard curve of Fe with R2 = 0.9999 is used for determination the content of Fe2+ and total iron with 2.5 mL 0.01% (w/v) SPION digested by HCl, pH = 4.30 HOAc-NaAc buffer 10 mL, 0.01% (w/v) 1,10-phenanthroline 5 mL and 10% (w/v) ascorbic acid 1 mL for total iron determine independently. But the presence of Fe3+ interfere with obtaining the actual value of Fe2+ (the error close to 9%). We designed a calibration curve to eliminate the error by devising a series of solution of different ratio of [Fe3+]/[Fe2+], and obtain the calibration curve. Through the calibration curve, the error between the measured value and the actual value can be reduced to 0.4%. The R2 of linearity of the method is 0.99441 and 0.99929 for Fe2+ and total iron respectively. The error of accuracy of recovery and precision of inter-day and intra-day are both lower than 2%, which can prove the reliability of the determination method.

  4. A study on the fabrication of superhydrophobic iron surfaces by chemical etching and galvanic replacement methods and their anti-icing properties

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kunquan, E-mail: likunquan1987@gmail.com; Zeng, Xingrong, E-mail: psxrzeng@gmail.com; Li, Hongqiang, E-mail: hqli1979@gmail.com; Lai, Xuejun, E-mail: msxjlai@scut.edu.cn

    2015-08-15

    Graphical abstract: - Highlights: • Superhydrophobic iron surfaces were prepared by etching and replacement method. • The fabrication process was simple, time-saving and inexpensive. • Galvanic replacement method was more favorable to create roughness on iron surface. • The superhydrophobic iron surface showed excellent anti-icing properties. - Abstract: Hierarchical structures on iron surfaces were constructed by means of chemical etching by hydrochloric acid (HCl) solution or the galvanic replacement by silver nitrate (AgNO{sub 3}) solution. The superhydrophobic iron surfaces were successfully prepared by subsequent hydrophobic modification with stearic acid. The superhydrophobic iron surfaces were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and water contact angle (WCA). The effects of reactive concentration and time on the microstructure and the wetting behavior were investigated. In addition, the anti-icing properties of the superhydrophobic iron surfaces were also studied. The FTIR study showed that the stearic acid was chemically bonded onto the iron surface. With the HCl concentration increase from 4 mol/L to 8 mol/L, the iron surface became rougher with a WCA ranging from 127° to 152°. The AgNO{sub 3} concentration had little effect on the wetting behavior, but a high AgNO{sub 3} concentration caused Ag particle aggregates to transform from flower-like formations into dendritic crystals, owing to the preferential growth direction of the Ag particles. Compared with the etching method, the galvanic replacement method on the iron surface more favorably created roughness required for achieving superhydrophobicity. The superhydrophobic iron surface showed excellent anti-icing properties in comparison with the untreated iron. The icing time of water droplets on the superhydrophobic surface was delayed to 500 s, which was longer than that of 295 s for

  5. Adsorption of antimony onto iron oxyhydroxides: Adsorption behavior and surface structure

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xuejun; Wu, Zhijun [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing 100875 (China); He, Mengchang, E-mail: hemc@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing 100875 (China); Meng, Xiaoguang [Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Jin, Xin [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing 100875 (China); Qiu, Nan; Zhang, Jing [Beijing Synchrotron Radiation Facility (BSRF), Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2014-07-15

    Graphical abstract: - Highlights: • Antimony adsorption depended on the Sb species, pH, and the type of iron oxides. • Sb(V) adsorption favored at acidic pH, Sb(III) adsorption optimized in wider pH. • Antimony was adsorbed onto the iron oxides by the inner-sphere surface complex. • Bidentate mononuclear ({sup 2}E) was the dominant form of Sb incorporated into HFO. • XAFS and XPS indicated Sb(III) adsorbed was slowly oxidized to Sb(V). - Abstract: Antimony is detected in soil and water with elevated concentration due to a variety of industrial applications and mining activities. Though antimony is classified as a pollutant of priority interest by the United States Environmental Protection Agency (USEPA) and Europe Union (EU), very little is known about its environmental behavior and adsorption mechanism. In this study, the adsorption behaviors and surface structure of antimony (III/V) on iron oxides were investigated using batch adsorption techniques, surface complexation modeling (SCM), X-ray photon spectroscopy (XPS) and extended X-ray absorption fine structure spectroscopy (EXAFS). The adsorption isotherms and edges indicated that the affinity of Sb(V) and Sb(III) toward the iron oxides depended on the Sb species, solution pH, and the characteristics of iron oxides. Sb(V) adsorption was favored at acidic pH and decreased dramatically with increasing pH, while Sb(III) adsorption was constant over a broad pH range. When pH is higher than 7, Sb(III) adsorption by goethite and hydrous ferric oxide (HFO) was greater than Sb(V). EXAFS analysis indicated that the majority of Sb(III), either adsorbed onto HFO or co-precipitated by FeCl{sub 3}, was oxidized into Sb(V) probably due to the involvement of O{sub 2} in the long duration of sample preservation. Only one Sb–Fe subshell was filtered in the EXAFS spectra of antimony adsorption onto HFO, with the coordination number of 1.0–1.9 attributed to bidentate mononuclear edge-sharing ({sup 2}E) between Sb and

  6. Determination of oxidation state of iron in normal and pathologically altered human aortic valves

    Energy Technology Data Exchange (ETDEWEB)

    Czapla-Masztafiak, J. [Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Kraków (Poland); Lis, G.J.; Gajda, M.; Jasek, E. [Department of Histology, Jagiellonian University Medical College, Kopernika 7, 31-034 Kraków (Poland); Czubek, U. [Department of Coronary Disease, Jagiellonian University Medical College, John Paul II Hospital, Prądnicka 80, 31-202 Kraków (Poland); Bolechała, F. [Department of Forensic Medicine, Jagiellonian University Medical College, Grzegórzecka 16, 31-531 Kraków (Poland); Borca, C. [Swiss Light Source, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Kwiatek, W.M. [Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Kraków (Poland)

    2015-12-01

    In order to investigate changes in chemical state of iron in normal and pathologically altered human aortic valves X-ray absorption spectroscopy was applied. Since Fe is suspected to play detrimental role in aortic valve stenosis pathogenesis the oxidation state of this element has been determined. The experimental material consisted of 10 μm sections of valves excised during routine surgery and from autopsies. The experiment was performed at the MicroXAS beamline of the SLS synchrotron facility in Villigen (Switzerland). The Fe K-edge XANES spectra obtained from tissue samples were carefully analyzed and compared with the spectra of reference compounds containing iron in various chemical structures. The analysis of absorption edge position and shape of the spectra revealed that both chemical forms of iron are presented in valve tissue but Fe{sup 3+} is the predominant form. Small shift of the absorption edge toward higher energy in the spectra from stenotic valve samples indicates higher content of the Fe{sup 3+} form in pathological tissue. Such a phenomenon suggests the role of Fenton reaction and reactive oxygen species in the etiology of aortic valve stenosis. The comparison of pre-edge regions of XANES spectra for control and stenotic valve tissue confirmed no differences in local symmetry or spin state of iron in analyzed samples.

  7. Determination of anisotropy constants of protein encapsulated iron oxide nanoparticles by electron magnetic resonance

    International Nuclear Information System (INIS)

    Li Hongyan; Klem, Michael T.; Sebby, Karl B.; Singel, David J.; Young, Mark; Douglas, Trevor; Idzerda, Yves U.

    2009-01-01

    Angle-dependent electron magnetic resonance was performed on 4.9, 8.0, and 19 nm iron oxide nanoparticles encapsulated within protein capsids and suspended in water. Measurements were taken at liquid nitrogen temperature after cooling in a 1 T field to partially align the particles. The angle dependence of the shifts in the resonance field for the iron oxide nanoparticles (synthesized within Listeria-Dps, horse spleen ferritin, and cowpea chlorotic mottle virus) all show evidence of a uniaxial anisotropy. Using a Boltzmann distribution for the particles' easy-axis direction, we are able to use the resonance field shifts to extract a value for the anisotropy energy, showing that the anisotropy energy density increases with decreasing particle size. This suggests that surface anisotropy plays a significant role in magnetic nanoparticles of this size

  8. Determination of anisotropy constants of protein encapsulated iron oxide nanoparticles by electron magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Li Hongyan [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Center for Bio-Inspired Nanomaterials, Montana State University, Bozeman, MT 59717 (United States); Klem, Michael T.; Sebby, Karl B.; Singel, David J. [Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717 (United States); Center for Bio-Inspired Nanomaterials, Montana State University, Bozeman, MT 59717 (United States); Young, Mark [Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717 (United States); Center for Bio-Inspired Nanomaterials, Montana State University, Bozeman, MT 59717 (United States); Douglas, Trevor [Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717 (United States); Center for Bio-Inspired Nanomaterials, Montana State University, Bozeman, MT 59717 (United States); Idzerda, Yves U. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Center for Bio-Inspired Nanomaterials, Montana State University, Bozeman, MT 59717 (United States)], E-mail: Idzerda@montana.edu

    2009-02-15

    Angle-dependent electron magnetic resonance was performed on 4.9, 8.0, and 19 nm iron oxide nanoparticles encapsulated within protein capsids and suspended in water. Measurements were taken at liquid nitrogen temperature after cooling in a 1 T field to partially align the particles. The angle dependence of the shifts in the resonance field for the iron oxide nanoparticles (synthesized within Listeria-Dps, horse spleen ferritin, and cowpea chlorotic mottle virus) all show evidence of a uniaxial anisotropy. Using a Boltzmann distribution for the particles' easy-axis direction, we are able to use the resonance field shifts to extract a value for the anisotropy energy, showing that the anisotropy energy density increases with decreasing particle size. This suggests that surface anisotropy plays a significant role in magnetic nanoparticles of this size.

  9. Microwave digestion for determination content of iron and zinc total in food

    International Nuclear Information System (INIS)

    Silva Trejos, Paulina

    2012-01-01

    The food digestion procedure was optimized by means of a microwave oven, to quantify the iron and total zinc in different matrices by atomic absorption spectroscopy. The optimum amount of concentrated HNO 3 was analyzed at 65% to digest sample mass determined by assessment of the percentage of recovery obtained with different amount of HNO 3 . The results have not differed from those obtained by officially recommended methods of acid digestion in open systems and calcination. (author) [es

  10. Influence of the tool construction on determination of iron-grade in parameter P-techniques

    International Nuclear Information System (INIS)

    Charbucinski, J.

    1975-01-01

    The results of laboratory tests for utilization of parameter P-technique in gamma-gamma method for the purpose of determination of iron content in an ore have been presented. Measurements were performed in the 4π geometry. The various dependences of the tool response on physical-technical parameters of the tool and the borehole-stratum system have been examined. Optimum construction of the borehole tool has been recommended. (author)

  11. Determination of calcium and iron in limestone by X-ray fluorescence method

    International Nuclear Information System (INIS)

    Sovtsova, M.K.

    1977-01-01

    The results of determining calcium and iron content in limestone by X-ray fluorescence method are described. The 109 Cd isotape was chosen as a source for excitation, as it permited to reduce the concentration degeneration in the range of large Ca contents due to the larger energy of the primary radiation. The root-mean-square deviation from the data of chemical analysis was +-0.02%FeO and +-0.22%CaO

  12. Bioavailability of iron to rats from processed soybean fractions determined by intrinsic and extrinsic labeling techniques

    International Nuclear Information System (INIS)

    Weaver, C.M.; Nelson, N.; Elliott, J.G.

    1984-01-01

    Intrinsic and extrinsic labeling techniques were used to measure iron bioavailability from soybean fractions (isolated soy protein, defatted flour, soy hulls, insoluble material and whey) by iron-depleted and non-iron-depleted rats. As expected, absorption of iron was higher in the iron-depleted than in the non-iron-depleted rats. In the iron-depleted group, significantly more iron was absorbed from soy whey than from other fractions. No other significant difference in iron absorption associated with iron source was observed. The higher absorption rate of iron from whey by the iron-depleted rats probably was related to a lower quantity of food consumed during the test meal by this group. Intrinsic and extrinsic labeling techniques produced similar assessments of bioavailability of iron

  13. Determining subnanomolar iron concentrations in oceanic seawater using a siderophore-modified film analyzed by infrared spectroscopy.

    Science.gov (United States)

    Roy, Eric G; Jiang, Cuihong; Wells, Mark L; Tripp, Carl

    2008-06-15

    Iron is a bioactive trace element in seawater that regulates photosynthetic carbon dioxide drawdown and export from surface waters by phytoplankton in upward of 40% of the world's oceans. While autonomous sensor arrays are beginning to provide high-resolution data on temporal and spatial scales for some key oceanographic parameters, current analytical methods for iron are not amenable to autonomous platforms because of the need for user involvement and wet chemistry-based approaches. As a result, very large gaps remain in our understanding of iron distribution and chemistry in seawater. Here we present a straightforward nanostructure-based method to measure dissolved iron in natural seawater. The device comprises an iron-specific chelating biomolecule, desferrioxamine B (DFB), covalently immobilized on a mesoporous silica film. Changes in infrared spectral signatures of the immobilized DFB upon Fe(III) complexation provide an accurate and precise measure of iron on the surface of a chip exposed to seawater. The current system has a detection limit of approximately 50 pM for a 1-L sample at pH 1.7 and was used to measure dissolved iron in subarctic Pacific waters without interference from other elements in seawater. This technology provides a major step toward obtaining accurate iron measurements on autonomous research platforms.

  14. Fermi Surface with Dirac Fermions in CaFeAsF Determined via Quantum Oscillation Measurements

    Science.gov (United States)

    Terashima, Taichi; Hirose, Hishiro T.; Graf, David; Ma, Yonghui; Mu, Gang; Hu, Tao; Suzuki, Katsuhiro; Uji, Shinya; Ikeda, Hiroaki

    2018-02-01

    Despite the fact that 1111-type iron arsenides hold the record transition temperature of iron-based superconductors, their electronic structures have not been studied much because of the lack of high-quality single crystals. In this study, we comprehensively determine the Fermi surface in the antiferromagnetic state of CaFeAsF, a 1111 iron-arsenide parent compound, by performing quantum oscillation measurements and band-structure calculations. The determined Fermi surface consists of a symmetry-related pair of Dirac electron cylinders and a normal hole cylinder. From analyses of quantum-oscillation phases, we demonstrate that the electron cylinders carry a nontrivial Berry phase π . The carrier density is of the order of 10-3 per Fe. This unusual metallic state with the extremely small carrier density is a consequence of the previously discussed topological feature of the band structure which prevents the antiferromagnetic gap from being a full gap. We also report a nearly linear-in-B magnetoresistance and an anomalous resistivity increase above about 30 T for B ∥c , the latter of which is likely related to the quantum limit of the electron orbit. Intriguingly, the electrical resistivity exhibits a nonmetallic temperature dependence in the paramagnetic tetragonal phase (T >118 K ), which may suggest an incoherent state. Our study provides a detailed knowledge of the Fermi surface in the antiferromagnetic state of 1111 parent compounds and moreover opens up a new possibility to explore Dirac-fermion physics in those compounds.

  15. First-principles simulations of iron with nitrogen: from surface adsorption to bulk diffusion

    International Nuclear Information System (INIS)

    Wu, M H; Liu, X H; Gu, J F; Jin, Z H

    2013-01-01

    Adsorption, absorption and diffusion pathways of nitrogen are studied for ferromagnetic body-centered cubic iron via spin-polarized density functional theory in combination with the climbing image nudged elastic band method. The computed data suggest that, depending on the coverage of N atoms, N prefers to stay on particular surface sites. Once pinned down well below the surface, N prefers to move into octahedral interstices rather than tetrahedral interstices. However, the tetrahedral interstices are crucial because they act as transition states and yield the saddle point energies of the corresponding minimum energy pathways. In comparison with carbon, we found that nitrogen prefers a different pathway from the (1 0 0) surface to the subsurface due to its strong repulsive interaction with Fe ions. (paper)

  16. Evaluation of Surface Roughness and Power Consumption in Machining FCD 450 Cast Iron using Coated and Uncoated Irregular Milling Tools

    International Nuclear Information System (INIS)

    Yusoff, Ahmad Razlan; Arsyad, Fitriyanti

    2016-01-01

    In this project, the effects of different cutting parameters on surface roughness and power consumption when machining FCD450 cast iron were studied using coated and uncoated irregular milling tool geometry of variable helix and pitch. Their responses on roughness and power consumption were evaluated based on the spindle speed, feed rate, and depth of cut, machining length and machining time. Results showed that except spindle speed and machining length, other parameters such as feed rate, axial and radial depth of cut and also machining time proportionate with surface roughness. The power consumption proportionately increase for all cutting parameters except feedrate. It is showed that the average decrement 27.92 percent for surface roughness and average decrement 9.32 percent for power consumption by using coated compared to uncoated tool. Optimum cutting parameters for both minimum surface roughness and power consumption can be determined. The coated tools performed better than uncoated milling tools for responses of surface roughness and power consumption to increase machining productivity and profit. (paper)

  17. Determination of iron, nickel, and chromium in the Masurca simulation rods

    International Nuclear Information System (INIS)

    Brigaudeau, M.; Pierdet, S.

    1969-01-01

    A method has been developed for determining the iron, nickel and chromium content of sintered ternary oxide rods designed to simulate structural elements in the reactor Masurca. During this work a calculation was made of the conditional constant of the Fe-EDTA complex in a formic buffer solution, and of that, of the Ni-EDTA complex in an ammoniacal buffer. From these two values it appears that it is not possible to carry out the iron and nickel determinations with a standard EDTA solution when these two elements are present simultaneously. That is the reason for which, in this case, a separation of the Fe and Ni is carried out in 8 N HCl solution on an anion exchange resin. Each element is then dosed by titricolorimetry. Chromium is determined by the same technique without prior separation. The reproducibility of the method has been calculated for each of the three elements. The relative accuracy is: 0.58 per cent for the iron; 1.41 per cent for the nickel; 0.39 per cent for the chromium. (authors) [fr

  18. Adsorption of poly(vinyl formamide-co-vinyl amine) (PVFA-co-PVAm) polymers on zinc, zinc oxide, iron, and iron oxide surfaces.

    Science.gov (United States)

    Seifert, Susan; Simon, Frank; Baumann, Giesela; Hietschold, Michael; Seifert, Andreas; Spange, Stefan

    2011-12-06

    The adsorption of poly(vinyl formamide) (PVFA) and the statistic copolymers poly(vinyl formamide-co-vinyl amine) (PVFA-co-PVAm) onto zinc and iron metal particles as well as their oxides was investigated. The adsorbates were characterized by means of XPS, DRIFT spectroscopy, wet chemical analysis, and solvatochromic probes. Dicyano-bis-(1,10-phenanthroline)-iron(II) (1), 3-(4-amino-3-methylphenyl)-7-phenyl-benzo-[1,2-b:4,5-b']difuran-2,6-dione (2), and 4-tert-butyl-2-(dicyano-methylene)-5-[4-(diethylamino)-benzylidene]-Δ(3)-thiazoline (3) as solvatochromic probes were coadsorbed onto zinc oxide to measure various effects of surface polarity. The experimental findings showed that the adsorption mechanism of PVFA and PVFA-co-PVAm strongly depends on the degree of hydrolysis of PVFA and pH values and also on the kind of metal or metal oxide surfaces that were employed as adsorbents. The adsorption mechanism of PVFA/PVFA-co-PVAm onto zinc oxide and iron oxide surfaces is mainly affected by electrostatic interactions. Particularly in the region of pH 5, the adsorption of PVFA/PVFA-co-PVAm onto zinc and iron metal particles is additionally influenced by redox processes, dissolution, and complexation reactions. © 2011 American Chemical Society

  19. Microstructural study and wear behavior of ductile iron surface alloyed by Inconel 617

    International Nuclear Information System (INIS)

    Arabi Jeshvaghani, R.; Jaberzadeh, M.; Zohdi, H.; Shamanian, M.

    2014-01-01

    Highlights: • The Ni-base alloy was deposited on the surface of ductile iron by TIG welding process. • Microstructure of alloyed layer consisted of carbides embedded in Ni-rich dendrite. • Hardness and wear resistance of coated sample greatly improved. • The formation of oxide layer and delamination were dominant mechanisms of wear. - Abstract: In this research, microstructure and wear behavior of Ni-based alloy is discussed in detail. Using tungsten inert gas welding process, coating of nearly 1–2 mm thickness was deposited on ductile iron. Optical and scanning electron microscopy, as well as X-ray diffraction analysis and electron probe microanalysis were used to characterize the microstructure of the surface alloyed layer. Micro-hardness and wear resistance of the alloyed layer was also studied. Results showed that the microstructure of the alloyed layer consisted of M 23 C 6 carbides embedded in Ni-rich solid solution dendrites. The partial melted zone (PMZ) had eutectic ledeburit plus martensite microstructure, while the heat affected zone (HAZ) had only a martensite structure. It was also noticed that hardness and wear resistance of the alloyed layer was considerably higher than that of the substrate. Improvement of wear resistance is attributed to the solution strengthening effect of alloying elements and also the presence of hard carbides such as M 23 C 6 . Based on worn surface analysis, the dominant wear mechanisms of alloyed layer were found to be oxidation and delamination

  20. Conversion electron Moessbauer spectroscopic studies on the chemical states of surface layers of corroded tin plates and tin-coated iron plates

    International Nuclear Information System (INIS)

    Kato, Akinori; Endo, Kazutoyo; Sano, Hirotoshi

    1980-01-01

    By means of the conversion electron Moessbauer spectroscopy (CEMS), we studied surface layers of ''tin'' plates and tin-coated iron plates corroded by various acids. Transmission Moessbauer spectra and X-ray diffraction patterns were also measured. Metastannic acid was formed, when the ''tin'' plate was corroded by nitric acid solution. In corrosion by phosphoric acid solution, the X-ray diffractometry revealed the formation of tin(IV) pyrophosphate. In corrosion by various organic acid solutions, the formation of oxides was identified by the 119 Sn CEMS, but not by the X-ray diffractometry because of the too thin corrosion layer. In corrosion of tin-coated iron plates, maleic acid, malonic acid, formic acid, and oxalic acid were used. It was determined by CEMS that the corrosion products caused by these acids were tin(IV) oxides, although they could not be identified by the X-ray diffractometry. CEMS also confirmed that the surface of uncorroded tin-coated iron plate was already oxidized by air. Colorimetric determinations of Sn and Fe dissolved from tin-coated iron plates to various acid solutions confirmed that maleic acid had the strongest corrosion effect among the organic acids studied. (author)

  1. Potential dependence of surface crystal structure of iron passive films in borate buffer solution

    International Nuclear Information System (INIS)

    Deng, Huihua; Nanjo, Hiroshi; Qian, Pu; Santosa, Arifin; Ishikawa, Ikuo; Kurata, Yoshiaki

    2007-01-01

    The effect of passivation potential on surface crystal structure, apparent thickness and passivity of oxide films formed on pure iron prepared by plasma sputter deposition was investigated. The crystallinity was improved with passivation potential and the width of atomically flat terraces was expanded to 6 nm when passivating at 750 mV for 15 min, as observed by ex situ scanning tunneling microscopy (STM) after aging in air (<30% RH). Apparent thickness and passivity are linearly dependent on passivation potential. The former weakly depends on passivation duration, the latter strongly depends on passivation duration. This is well explained by the correlation between crystal structure and passivity

  2. Atomic absorption determination of iron and copper impurities in rare earth compounds

    International Nuclear Information System (INIS)

    Zelyukova, Yu.V.; Kravchenko, J.B.; Kucher, A.A.

    1978-01-01

    An extraction atomic absorption method for the determination of copper and iron impurities in rare earth compounds has been developed. The extraction separation of determined elements as hydroxy quinolinates with isobuthyl alcohol was used. It increased the sensitivity of these element determination and excluded the effect of the analysed sample. Cu, Te, Zn, Bi, Sn, In, Ga, Tl and the some other elements can be determined at pH 2.0-3.0 but rare earths are remained in an aqueous phase. The condition of the flame combustion does not change during the introduction of isobutyl extract but the sensitivity of the determination of the elements increased 2-3 times. The limit of Fe determination is 0.01 mg/ml and the limit of Cu determination is 0.014 mg/ml

  3. Determination of natural organic matter and iron binding capacity in fen samples

    Science.gov (United States)

    Kügler, Stefan; Cooper, Rebecca E.; Frieder Mohr, Jan; Wichard, Thomas; Küsel, Kirsten

    2017-04-01

    illustrated by van Krevelen plots, which indicate the presence of different substance classes including condensed aromatics, lignins and tannins known to complex iron. Our results indicate a variety of potential Fe-DOM-complexes present in the PWE samples when iron is incorporated into the elemental composition search. Using DPP we determine the complexation capacity of iron in the natural matrix of the fen along with the identification of ligands in order to estimate the iron bioavailability for bacteria. As the microbial redox system of the fen is impacted by other metals in the environment, we perform comprehensive analysis of the entirety of metal ions and concentrations in the water samples. Dialysis chambers are currently installed in the iron-rich fen from which pore water samples will be collected at 1 cm increments between 0-20 cm depth to determine the depth profiles of Fe(II)- and Fe(III)-concentration and evaluate the influence of the depth profiles on the interplay between microorganism comprising the natural microbial redox system of the fen. We have shown that metal-DOM-pH interactions affect the bioavailable metal concentration in fen water systems. This information will pave the way for a better understanding of the bacterial recruitment of trace elements and microbial redox reactions.

  4. A simplified method for determination of radioactive iron in whole-blood samples

    DEFF Research Database (Denmark)

    Bukhave, Klaus; Sørensen, Anne Dorthe; Hansen, M.

    2001-01-01

    in humans. The overall recovery of radioiron from blood is more than 90%, and the coefficient of variation, as judged by the variation in the ratio Fe-55/Fe-59 is in the order of 4%. Combined with whole-body counting of 59Fe and direct gamma -counting of Fe-59 on blood samples, this method represents......For studies on iron absorption in man radioisotopes represent an easy and simple tool. However, measurement of the orbital electron emitting radioiron, Fe-55, in blood is difficult and insufficiently described in the literature. The present study describes a relatively simple method...... for simultaneous determination of Fe-55 and Fe-59 in blood, using a dry-ashing procedure and recrystallization of the remaining iron. The detection Limit of the method permits measurements of 0.1 Bq/ml blood thus allowing detection of Less than 1% absorption from a 40 kBq dose, which is ethically acceptable...

  5. Size-controlled synthesis of superparamagnetic iron oxide nanoparticles and their surface coating by gold for biomedical applications

    International Nuclear Information System (INIS)

    Maleki, H.; Simchi, A.; Imani, M.; Costa, B.F.O.

    2012-01-01

    The size mono-dispersity, saturation magnetization, and surface chemistry of magnetic nanoparticles (NPs) are recognized as critical factors for efficient biomedical applications. Here, we performed modified water-in-oil inverse nano-emulsion procedure for preparation of stable colloidal superparamagnetic iron oxide NPs (SPIONs) with high saturation magnetization. To achieve mono-dispersed SPIONs, optimization process was probed on several important factors including molar ratio of iron salts [Fe 3+ and Fe 2+ ], the concentration of ammonium hydroxide as reducing agent, and molar ratio of water to surfactant. The biocompatibility of the obtained NPs, at various concentrations, was evaluated via MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay and the results showed that the NPs were non-toxic at concentrations 3 O 4 core/Au shell particles demonstrate strong plasmon resonance absorption and can be separated from solution using an external magnetic field. Experimental data from both physical and chemical determinations of the changes in particle size, surface plasmon resonance optical band, phase components, core–shell surface composition, and magnetic properties have confirmed the formation of the mono-dispersed core–shell nanostructure. - Highlights: ► Increasing the concentration of iron salts, cubic-shape SPION NPs were formed. The magnetic saturation of the SPIONs was also increased. ► The concentration of reducing agent exhibited marginal effect on the size of SPIONs but influenced the crystallinity of the NPs. A lower magnetic saturation was obtained at higher NH 4 OH concentrations. ► Mono-dispersed SPIONs can be prepared by nano-emulsion procedure at w=23, [Fe]=2.12 M, and [NH 4 OH]=30%. Under this condition, NPs with dimension of 9±3 nm and magnetic saturation of 54 emu/g are obtained. The synthesized SPIONs exhibited acceptable biocompatibility, >80% viability after 24 h incubation in L929 cells at concentrations <0

  6. Ion-Selective Electrode for the Determination of Iron(III in Vitamin Formulations

    Directory of Open Access Journals (Sweden)

    Teixeira Marcos Fernando de S.

    1998-01-01

    Full Text Available A coated graphite-epoxy ion-selective electrode for iron(III, based on the ion-pair formed between [Fe(citrate2]3- and the tricaprylylmethylammonium cation (Aliquat 336 in a poly(vinylchloride (PVC matrix has been constructed. A thin membrane film of this ion-pair, dibutylphthalate (DBPh in PVC was deposited directly onto a Perspex® tube, which contained a graphite-epoxy conductor substrate. The coating solution was prepared by dissolving 30% (w/w of PVC in 10 mL of tetrahydrofuran following addition of 65% (w/w DBPh and 5% (w/w of the ionic pair. The effect of pH, citrate concentration and some cations on the electrode response has been investigated. The E(mV vs. log [Fe(citrate2]3- electrode response was linear for iron(III concentration from 1.0 x 10-3 mol/L to 1.0 x 10-1 mol/L in 1.0 mol/L citrate medium, with a slope of 19.3 ± 0.5 mV/decade and a useful lifetime of at least six months (more than 800 determinations for each polymeric membrane used. The detection limit was 7.5 x 10-4 mol/L and the relative standard deviation was less than 3% for a solution containing 5.0 x 10-3 mol/L of iron(III (n = 10. The application of this electrode for iron(III determination in samples of vitamin formulations is described. The results obtained with this procedure are in close agreement with those obtained using AA spectrophotometry (r = 0.9999.

  7. Facile fabrication of iron-based superhydrophobic surfaces via electric corrosion without bath

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-30

    carbon steel substrate under appropriate process; the contact angle of the as-prepared superhydrophobic surface can be up to 152 ± 0.5°, and the sliding angle is 1–2°; its anti-corrosion property, anti-icing performance and the friction property all show an excellent level. This method provides the possibility of industrialization of superhydrophobic surface based on iron substrate as it can prepare massive superhydrophobic surface quickly.

  8. Recent advances in synthesis and surface modification of superparamagnetic iron oxide nanoparticles with silica

    International Nuclear Information System (INIS)

    Sodipo, Bashiru Kayode; Aziz, Azlan Abdul

    2016-01-01

    Research on synthesis of superparamagnetic iron oxide nanoparticles (SPION) and its surface modification for biomedical applications is of intense interest. Due to superparamagnetic property of SPION, the nanoparticles have large magnetic susceptibility, single magnetic domain and controllable magnetic behaviour. However, owing to easy agglomeration of SPION, surface modification of the magnetic particles with biocompatible materials such as silica nanoparticle has gained much attention in the last decade. In this review, we present recent advances in synthesis of SPION and various routes of producing silica coated SPION. - Highlights: • We present recent advances in synthesis of SPION and various routes of producing silica coated SPION • The synthetic routes of producing SPION can be classified into three: physical, chemical and biological methods. • The chemical method is the most cited method of producing SPION and it sub-classified into liquid and gas phase. • The techniques of producing silica coated SPION is grouped into seeded and non-seeded methods.

  9. Recent advances in synthesis and surface modification of superparamagnetic iron oxide nanoparticles with silica

    Energy Technology Data Exchange (ETDEWEB)

    Sodipo, Bashiru Kayode, E-mail: bashirsodipo@gmail.com [School of Physics, Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia); Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia); Aziz, Azlan Abdul [School of Physics, Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia); Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia)

    2016-10-15

    Research on synthesis of superparamagnetic iron oxide nanoparticles (SPION) and its surface modification for biomedical applications is of intense interest. Due to superparamagnetic property of SPION, the nanoparticles have large magnetic susceptibility, single magnetic domain and controllable magnetic behaviour. However, owing to easy agglomeration of SPION, surface modification of the magnetic particles with biocompatible materials such as silica nanoparticle has gained much attention in the last decade. In this review, we present recent advances in synthesis of SPION and various routes of producing silica coated SPION. - Highlights: • We present recent advances in synthesis of SPION and various routes of producing silica coated SPION • The synthetic routes of producing SPION can be classified into three: physical, chemical and biological methods. • The chemical method is the most cited method of producing SPION and it sub-classified into liquid and gas phase. • The techniques of producing silica coated SPION is grouped into seeded and non-seeded methods.

  10. Effects of surface condition on aqueous corrosion and environmental embrittlement of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Perrin, R.L.; Buchanan, R.A. [Univ. of Tennessee, Knoxville, TN (United States)

    1996-08-01

    Effects of retained high-temperature surface oxides, produced during thermomechanical processing and/or heat treatment, on the aqueous-corrosion and environmental-embrittlement characteristics of Fe{sub 3}Al-based iron aluminides (FA-84, FA-129 and FAL-Mo), a FeAl-based iron aluminide (FA-385), and a disordered low-aluminum Fe-Al alloy (FAPY) were evaluated. All tests were conducted at room temperature in a mild acid-chloride solution. In cyclic-anodic-polarization testing for aqueous-corrosion behavior, the surface conditions examined were: as-received (i.e., with the retained high-temperature oxides), mechanically cleaned and chemically cleaned. For all materials, the polarization tests showed the critical pitting potentials to be significantly lower in the as-received condition than in the mechanically-cleaned and chemically-cleaned conditions. These results indicate detrimental effects of the retained high-temperature oxides in terms of increased susceptibilities to localized corrosion. In 200-hour U-bend stress-corrosion-cracking tests for environmental-embrittlement behavior, conducted at open-circuit corrosion potentials and at a hydrogen-charging potential of {minus}1500 mV (SHE), the above materials (except FA-385) were examined with retained oxides and with mechanically cleaned surfaces. At the open-circuit corrosion potentials, none of the materials in either surface condition underwent cracking. At the hydrogen-charging potential, none of the materials with retained oxides underwent cracking, but FA-84, FA-129 and FAL-Mo in the mechanically cleaned condition did undergo cracking. These results suggest beneficial effects of the retained high-temperature oxides in terms of increased resistance to environmental hydrogen embrittlement.

  11. Enlightening mineral iron sensing in Pseudomonas fluorescens by surface active maghemite nanoparticles: Involvement of the OprF porin.

    Science.gov (United States)

    Magro, Massimiliano; Fasolato, Luca; Bonaiuto, Emanuela; Andreani, Nadia Andrea; Baratella, Davide; Corraducci, Vittorino; Miotto, Giovanni; Cardazzo, Barbara; Vianello, Fabio

    2016-10-01

    Mineral iron(III) recognition by bacteria is considered a matter of debate. The peculiar surface chemistry of novel naked magnetic nanoparticles, called SAMNs (surface active maghemite nanoparticles) characterized by solvent exposed Fe(3+) sites on their surface, was exploited for studying mineral iron sensing in Pseudomonas fluorescens. SAMNs were applied for mimicking Fe(3+) ions in solution, acting as magnetically drivable probes to evaluate putative Fe(3+) recognition sites on the microorganism surface. Culture broths and nano-bio-conjugates were characterized by UV-Vis spectroscopy and mass spectrometry. The whole heritage of a membrane porin (OprF) of P. fluorescens Ps_22 cells was recognized and firmly bound by SAMNs. The binding of nanoparticles to OprF porin was correlated to a drastic inhibition of a siderophore (pyoverdine) biosynthesis and to the stimulation of the production and rate of formation of a secondary siderophore. The analysis of metabolic pathways, based on P. fluorescens Ps_22 genomic information, evidenced that this putative secondary siderophore does not belong to a selection of the most common siderophores. In the scenario of an adhesion mechanism, it is plausible to consider OprF as the biological component deputed to the mineral iron sensing in P. fluorescens Ps_22, as well as one key of siderophore regulation. The present work sheds light on mineral iron sensing in microorganisms. Peculiar colloidal naked iron oxide nanoparticles offer a useful approach for probing the adhesion of bacterial surface on mineral iron for the identification of the specific recognition site for this iron uptake regulation in microorganisms. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Biofilm Surface Density Determines Biocide Effectiveness

    Directory of Open Access Journals (Sweden)

    Sara Bas

    2017-12-01

    Full Text Available High resistance of biofilms for chemical challenges is a serious industrial and medical problem. In this work a gradient of surface covered with biofilm has been produced and correlated to the effectiveness of different commercially available oxidative biocides. The results for thin Escherichia coli biofilms grown in rich media supplemented with glucose or lactose on glass or poly methyl methacrylate surfaces indicate that the effectiveness of hydrogen peroxide or chlorine dioxide and quaternary ammonium compounds is inversely proportional to the fraction of the surface covered with the biofilm. In areas where biofilm covered more than 90% of the available surface the biocide treatment was inefficient after 60 min of incubation. The combined effect of oxidant and surfactant increased the effectiveness of the biocide. On the other hand, the increased biofilm viscoelasticity reduced biocide effectiveness. The results emphasize differential biocide effectiveness depending on the fraction of the attached bacterial cells. The results suggest that biofilm biocide resistance is an acquired property that increases with biofilm maturation. The more dense sessile structures present lower log reductions compared to less dense ones.

  13. DETERMINATION OF SURFACE CHARGE DENSITY OF α ...

    African Journals Online (AJOL)

    a

    The whole set up was interfaced with a computer for easy data acquisition. It was observed that ... parameters. KEY WORDS: Alumina, Surface charge density, Acid-base titration, Point of zero charge ... For instance, Al2(SO4)3 is used in water ...

  14. Standard test method for determining nodularity and nodule count in ductile iron using image analysis

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method is used to determine the percent nodularity and the nodule count per unit area (that is, number of nodules per mm2) using a light microscopical image of graphite in nodular cast iron. Images generated by other devices, such as a scanning electron microscope, are not specifically addressed, but can be utilized if the system is calibrated in both x and y directions. 1.2 Measurement of secondary or temper carbon in other types of cast iron, for example, malleable cast iron or in graphitic tool steels, is not specifically included in this standard because of the different graphite shapes and sizes inherent to such grades 1.3 This standard deals only with the recommended test method and nothing in it should be construed as defining or establishing limits of acceptability or fitness for purpose of the material tested. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 This standard does not purport to address al...

  15. Surface interactions between nanoscale iron and organic material: Potential uses in water treatment process units

    Science.gov (United States)

    Storms, Max

    Membrane systems are among the primary emergent technologies in water treatment process units due to their ease of use, small physical footprint, and high physical rejection. Membrane fouling, the phenomena by which membranes become clogged or generally soiled, is an inhibitor to optimal efficiency in membrane systems. Novel, composite, and modified surface materials must be investigated to determine their efficacy in improving fouling behavior. Ceramic membranes derived from iron oxide nanoparticles called ferroxanes were coated with a superhydrophillic, zwitterionic polymer called poly (sulfobetaine methacrylate) (polySBMA) to form a composite ceramic-polymeric membrane. Membrane samples with and without polySBMA coating were subjected to fouling with a bovine serum albumin solution and fouling was observed by measuring permeate flux at 10 mL intervals. Loss of polySBMA was measured using total organic carbon analysis, and membrane samples were characterized using x-ray diffraction, scanning electron microscopy, and optical profilometry. The coated membrane samples decreased initial fouling rate by 27% and secondary fouling rate by 24%. Similarly, they displayed a 30% decrease in irreversible fouling during the initial fouling stage, and a 27% decrease in irreversible fouling in the secondary fouling stage; however, retention of polySBMA sufficient for improved performance was not conclusive. The addition of chemical disinfectants into drinking water treatment processes results in the formation of compounds called disinfection by-products (DBPs). The formation of DBPs occurs when common chemical disinfectants (i.e. chlorine) react with organic material. The harmful effects of DBP exposure require that they be monitored and controlled for public safety. This work investigated the ability of nanostructured hematite derived from ferroxane nanoparticles to remove organic precursors to DBPs in the form of humic acid via adsorption processes. The results show that p

  16. DETERMINATION OF THE RATES AND PRODUCTS OF FERROUS IRON OXIDATION IN ARSENIC-CONTAMINATED POND WATER.

    Science.gov (United States)

    Dissolved ferrous iron and arsenic in the presence of insufficient oxygenated ground water is released into a pond. When the mixing of ferrous iron and oxygenated water within the pond occurs, the ferrous iron is oxidized and precipitated as an iron oxide. Groups of experiments...

  17. Determining the Effect of Environmental Conditions on Iron Corrosion by Atomic Absorption

    Science.gov (United States)

    Malel, Esteban; Shalev, Deborah E.

    2013-01-01

    Iron corrosion is a complex process that occurs when iron is exposed to oxygen and humidity and is exacerbated by the presence of chloride ions. The deterioration of iron structures or other components can be costly to society and is usually evaluated by following the properties of the corroding material. Here, the iron ions released into solution…

  18. The effect of neutral-surface iron oxide nanoparticles on cellular uptake and signaling pathways

    Directory of Open Access Journals (Sweden)

    Kim E

    2016-09-01

    Full Text Available Eunjoo Kim,1 Joon Mee Kim,2 Lucia Kim,2 Suk Jin Choi,2 In Suh Park,2 Jee Young Han,2 Young Chae Chu,2 Eun Sook Choi,1 Kun Na,3 Soon-Sun Hong4 1Division of Nano and Energy Convergence Research, Daegu Gyeongbuk Institute of Science and Technology (DGIST, Daegu, 2Department of Pathology, Inha University College of Medicine, Incheon, 3Department of Biotechnology, Catholic University of Korea, Bucheon, 4Department of Biomedical Sciences, Inha University College of Medicine, Incheon, South Korea Abstract: In recent years, iron oxide nanoparticles (IONPs have been applied widely to biomedical fields. However, the relationship between the physicochemical properties of IONPs and their biological behavior is not fully understood yet. We prepared 3-methacryloxypropyl­trimethoxysilane (MPS-coated IONPs, which have a neutral hydrophobic surface, and compared their biological behavior to that of Resovist (ferucarbotran, a commercialized IONP formulation modified with carboxymethyl dextran. The rate of MPS-IONP uptake by human aortic endothelial cells (HAoECs was higher than ferucarbotran uptake, indicating that the neutral hydrophobic nature of MPS-IONPs allowed them to be absorbed more readily through the plasma membrane. However, the signaling pathways activated by MPS-IONPs and ferucarbotran were comparable, suggesting that surface charge is not a key factor for inducing changes in HAoECs. In vivo fate analysis showed that MPS-IONPs accumulated for longer periods in tissues than hydrophilic ferucarbotran. These findings could enlarge our understanding of NP behavior for advanced applications in the biomedical field. Keywords: iron oxide nanoparticles, neutral hydrophobic surface, signaling pathway, uptake, accumulation, reactive oxygen species (ROS

  19. Rapid photometric determination of phosphorus in iron ores and related materials as phosphomolybdenum-blue.

    Science.gov (United States)

    Bhargava, O P; Gmitro, M

    1984-04-01

    A rapid, simple and accurate method for determining phosphorus photometrically in iron ores and related materials, obviating the use of perchloric acid, is described. The sample is fused with sodium peroxide in a zirconium crucible and the melt dissolved in hydrochloric acid. The molybdenum-blue complex is developed by the addition of ammonium molybdate and hydrazine sulphate and the absorbance is measured at 725 nm. The range of the method is from 0.005 to 1.0% P. A batch of 6 samples can be analysed in about 2 hr.

  20. Determination of iron and titanium in kaolins by the method of non-dispersive X-ray fluorescence

    International Nuclear Information System (INIS)

    Bialy, N.; Kierzek, J.; Parus, J.

    1976-01-01

    The possibility of application of the radioactive source excited X-ray fluorescence analysis for titanium and iron determination in kaolins to the routine test of the refinement process has been studied. The iron content can be determined with a simple counting system using a single-channel pulse height analyser, argon filled proportional counter and 109 Cd source of 3 mCi for the excitation of K Fe rays. The samples were analyzed both as pellets and powders. The iron content ranged from 0.2-2.5% and titanium from 0.1-0.64%. The best values of precision and determination limit have been achieved for iron with 238 Pu and for titanium with 55 Fe. The precision and accuracy of the X-ray fluorescence method of iron and titanium determination in kaolins are comparable to those of the chemical method. For the simultaneous iron and titanium determination in the discussed region of concentration it is the most advantageous to use the plutonium source with the activity of several tens of mCi and Si(Li) detector with a moderate resolution (250-300 eV for 5.9 keV). The time of the analysis carried out by the described method is several times shorter than the chemical method. The apparatus used in this method is relatively simple, the sample preparation does not require any chemical treatment and the cost of labour of the sample preparation is minimal. (T.G.)

  1. Deposition of a thin electro-polymerized organic film on iron surface

    International Nuclear Information System (INIS)

    Lecayon, Gerard

    1980-01-01

    We use an electrochemical method to prepare a polymerized thin film, obtained from acrylonitrile in a solution of acetonitrile and tetraethylammonium perchlorate. The films are deposited on oxidized iron electrodes, with a surface area varying from a few mm to several cm, their thickness ranges from ten A to thousand A. This result is obtained by controlling the evolution of reactions: duplication, hydrogenation, polymerization which occur during the electrochemical reduction of acrylonitrile. The choice of suitable experimental conditions enhances the polymerization and increases the adherence of the polymer on the electrode. The usual methods of surface studies: S.E.M., A.E.S., S.I.M.S., permit the characterization of the electrode surface and the chemical composition of the deposit films. The molecular structure of polymer, and its evolution under aging or heating was studied by infrared multi-reflection spectroscopy. Very good correlation exists between the electrochemical characteristic: I = f(t), the initial surface state of the electrodes, and the homogeneity of the electro-polymerized films. Diagrams corresponding to mechanisms of different stages of electro-polymerization are proposed. (author) [fr

  2. Modification of the surface of superparamagnetic iron oxide nanoparticles to enable their safe application in humans.

    Science.gov (United States)

    Strehl, Cindy; Maurizi, Lionel; Gaber, Timo; Hoff, Paula; Broschard, Thomas; Poole, A Robin; Hofmann, Heinrich; Buttgereit, Frank

    Combined individually tailored methods for diagnosis and therapy (theragnostics) could be beneficial in destructive diseases, such as rheumatoid arthritis. Nanoparticles are promising candidates for theragnostics due to their excellent biocompatibility. Nanoparticle modifications, such as improved surface coating, are in development to meet various requirements, although safety concerns mean that modified nanoparticles require further review before their use in medical applications is permitted. We have previously demonstrated that iron oxide nanoparticles with amino-polyvinyl alcohol (a-PVA) adsorbed on their surfaces have the unwanted effect of increasing human immune cell cytokine secretion. We hypothesized that this immune response was caused by free-floating PVA. The aim of the present study was to prevent unwanted immune reactions by further surface modification of the a-PVA nanoparticles. After cross-linking of PVA to nanoparticles to produce PVA-grafted nanoparticles, and reduction of their zeta potential, the effects on cell viability and cytokine secretion were analyzed. PVA-grafted nanoparticles still stimulated elevated cytokine secretion from human immune cells; however, this was inhibited after reduction of the zeta potential. In conclusion, covalent cross-linking of PVA to nanoparticles and adjustment of the surface charge rendered them nontoxic to immune cells, nonimmunogenic, and potentially suitable for use as theragnostic agents.

  3. Reduction-induced inward diffusion and crystal growth on the surfaces of iron-bearing silicate glasses

    DEFF Research Database (Denmark)

    Liu, S.J.; Tao, H.Z.; Zhang, Y.F.

    2015-01-01

    We investigate the sodium inward diffusion (i.e., sodium diffusion from surface toward interior) in iron containing alkaline earth silicate glasses under reducing conditions around Tg and the induced surface crystallization. The surface crystallization is caused by formation of a silicate-gel lay......+ ions have stronger bonds to oxygen and lower coordination number (4~5) than Ca2+, Sr2+ and Ba2+ ions. In contrast, a cristobalite layer forms in Ca-, Sr- and Ba-containing glasses....

  4. Oxidation state of sulfur, iron and tin at the surface of float glasses

    International Nuclear Information System (INIS)

    Lagarde, P; Flank, A-M; Jupille, J; Montigaud, H

    2009-01-01

    Sulfur is an important element of glasses, not because of its amount, always very low (less than 0.4 % in weight of SO 3 ), but because of its role since it actively participates to the refinement process and, combined to other elements, it can be responsible for the coloration of the glass. Iron is also of a major importance in most of the glasses. In the case of the float glass, the two faces, because of the fabrication process, are different in terms of composition (presence of Sn for one face) and also in terms of oxidation state of these minority elements (Fe, Sn, S). There should be a subtle interplay between the concentrations and the oxidation states of these different minority elements, and anyway these variations occur over a thickness of the order of few micrometers below the surface. Using the high intensity and the focusing properties (3 x 3 μm 2 ) of the x-ray beam from the Lucia beamline, we have therefore studied the speciation of iron and sulfur near the face of a float glass in relation with the behavior of tin. This has been obtained by combining elemental x-ray fluorescence cartography and x-ray micro-absorption at the different K-edges.

  5. Oxidation state of sulfur, iron and tin at the surface of float glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lagarde, P; Flank, A-M [Synchrotron SOLEIL, l' Orme des Merisiers, BP 48 91192 Gif/Yvette cedex (France); Jupille, J [IMPMC, Universite P. and M. Curie, Campus de Boucicaut, 140 rue de Lourmel 75015 Paris (France); Montigaud, H [Saint-Gobain Recherche 39, quai Lucien Lefranc, BP 135 93303 Aubervilliers Cedex (France)

    2009-11-15

    Sulfur is an important element of glasses, not because of its amount, always very low (less than 0.4 % in weight of SO{sub 3}), but because of its role since it actively participates to the refinement process and, combined to other elements, it can be responsible for the coloration of the glass. Iron is also of a major importance in most of the glasses. In the case of the float glass, the two faces, because of the fabrication process, are different in terms of composition (presence of Sn for one face) and also in terms of oxidation state of these minority elements (Fe, Sn, S). There should be a subtle interplay between the concentrations and the oxidation states of these different minority elements, and anyway these variations occur over a thickness of the order of few micrometers below the surface. Using the high intensity and the focusing properties (3 x 3 {mu}m{sup 2}) of the x-ray beam from the Lucia beamline, we have therefore studied the speciation of iron and sulfur near the face of a float glass in relation with the behavior of tin. This has been obtained by combining elemental x-ray fluorescence cartography and x-ray micro-absorption at the different K-edges.

  6. Spectrophotometric determination of phosphorus in iron alloys employing a flow injection system

    Directory of Open Access Journals (Sweden)

    Gervasio Ana P. G.

    2001-01-01

    Full Text Available A flow-injection procedure for spectrophotometric determination of phosphorus in electrolytic iron and iron alloys is proposed. The method is based on the ammonium molybdate reaction followed by stannous chloride reduction in acidic medium. In order to circumvent the severe interference caused by the major constituents such as Fe(III and Cr(III, a mini-column packed with AG50W-X8 resin was coupled to the manifold. A sample throughput of 40 determinations per hour, a dynamical range from P 0.25 to 6.00 mg L-1, a reagent consumption of 25 mg ammonium molybdate and 2 mg stannous chloride per determination, and a relative standard deviation < 1% (n = 10 for a typical sample with 2.20 mg L-1 P were achieved. Three different types of samples were used to evaluate system performance. Accuracy was assessed by comparing the results with certified values and no significant difference at 95 % confidence level was observed.

  7. An example of the application of Mössbauer spectroscopy for determination of concentration of iron in lyophilized brain tissue

    Directory of Open Access Journals (Sweden)

    Rzepecka Patrycja

    2017-06-01

    Full Text Available Mössbauer spectroscopy is not routinely used for the determination of the concentration of iron. However, as this method does not need any pre-treatment of samples before measurements, it may be of extreme importance for the assessment of iron in samples, which can then be used for further investigations. Biological samples are a good example, however, as the concentrations of iron are very low in these, it is important to exclude possible artefacts from the background spectrum related to iron present in the counter and cryostat windows. The aim of this study was to compare two methods of determination of the amounts of iron in investigated sample: one, in which the background spectrum was subtracted from the sample spectrum measured, and the other, in which the obtained non-elaborated spectrum was fitted with two doublets - a doublet for the measured sample and a doublet for the background spectrum. Three samples containing known amounts of natural iron (400, 800 and 1600 μg and a sample of lyophilized human brain tissue obtained from globus pallidus were assessed. Both methods led to the creation of a very good calibration curve with a correlation coefficient of 0.99. Although both methods gave similar results for the concentration of iron in the sample, the subtraction of the background spectrum had a significantly lower error of the final result.

  8. Determination of the surface drag coefficient

    DEFF Research Database (Denmark)

    Mahrt, L.; Vickers, D.; Sun, J.L.

    2001-01-01

    This study examines the dependence of the surface drag coefficient on stability, wind speed, mesoscale modulation of the turbulent flux and method of calculation of the drag coefficient. Data sets over grassland, sparse grass, heather and two forest sites are analyzed. For significantly unstable...... conditions, the drag coefficient does not depend systematically on z/L but decreases with wind speed for fixed intervals of z/L, where L is the Obukhov length. Even though the drag coefficient for weak wind conditions is sensitive to the exact method of calculation and choice of averaging time, the decrease...... of the drag coefficient with wind speed occurs for all of the calculation methods. A classification of flux calculation methods is constructed, which unifies the most common previous approaches. The roughness length corresponding to the usual Monin-Obukhov stability functions decreases with increasing wind...

  9. The shaping of zinc coating on surface steels and ductile iron casting

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2010-01-01

    Full Text Available The studies aimed at an analysis of the formation and growth kinetics of zinc coating on reactive silicon-killed steels in a zinc bath. The growth kinetics of the produced zinc coatings was evaluated basing on the power-law growth equation. As regards galvanizing of the surface of products, investigation was done for various steel grades and ductile iron (DI taking into account the quality and thickness of coating. It has been proved that the chemical constitution of basis significantly influences the kinetics of growth of the individual phases in a zinc coating. This relationship was evaluated basing on the, so called, silicon and phosphorus equivalent ESi,P and coating thickness dependences were obtained.

  10. Synthesis of ultrasmall magnetic iron oxide nanoparticles and study of their colloid and surface chemistry

    International Nuclear Information System (INIS)

    Goloverda, Galina; Jackson, Barry; Kidd, Clayton; Kolesnichenko, Vladimir

    2009-01-01

    Colloidal nanoparticles of Fe 3 O 4 (4 nm) were synthesized by high-temperature hydrolysis of chelated iron (II) and (III) diethylene glycol alkoxide complexes in a solution of the parent alcohol (H 2 DEG) without using capping ligands or surfactants: [Fe(DEG)Cl 2 ] 2- +2[Fe(DEG)Cl 3 ] 2- +2H 2 O+2OH - →Fe 3 O 4 +3H 2 DEG+8Cl - The obtained particles were reacted with different small-molecule polydentate ligands, and the resulting adducts were tested for aqueous colloid formation. Both the carboxyl and α-hydroxyl groups of the hydroxyacids are involved in coordination to the nanoparticles' surface. This coordination provides the major contribution to the stability of the ligand-coated nanoparticles against hydrolysis.

  11. Optimization of Reactive Blue 21 removal by Nanoscale Zero-Valent Iron using response surface methodology

    Directory of Open Access Journals (Sweden)

    Mahmood Reza Sohrabi

    2016-07-01

    Full Text Available Since Reactive Blue 21 (RB21 is one of the dye compounds which is harmful to human life, a simple and sensitive method to remove this pollutant from wastewater is using Nano Zero-Valent Iron (NZVI catalyst. In this paper, a Central Composite Rotatable Design (CCRD was employed for response surface modeling to optimize experimental conditions of the RB21 removal from aqueous solution. The significance and adequacy of the model were analyzed using analysis of variance (ANOVA. Four independent variables—including catalyst amount (0.1–0.9 g, pH (3.5–9.5, removal time (30–150 s and dye concentration (10–50 mg/L—were transformed to coded values and consequently second order quadratic model was built to predict the responses. The result showed that under optimized experimental conditions the removal of RB21 was over 95%.

  12. Surface water iron supplies in the Southern Ocean sustained by deep winter mixing

    CSIR Research Space (South Africa)

    Tagliabue, A

    2014-04-01

    Full Text Available Low levels of iron limit primary productivity across much of the Southern Ocean. At the basin scale, most dissolved iron is supplied to surfacewaters from subsurface reservoirs, because land inputs are spatially limited. Deep mixing in winter...

  13. Surface materials map of Afghanistan: iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Kokaly, Raymond F.; Hoefen, Todd M.; Dudek, Kathleen B.; Livo, Keith E.

    2012-01-01

    This map shows the distribution of selected iron-bearing minerals and other materials derived from analysis of HyMap imaging spectrometer data of Afghanistan. Using a NASA (National Aeronautics and Space Administration) WB-57 aircraft flown at an altitude of ~15,240 meters or ~50,000 feet, 218 flight lines of data were collected over Afghanistan between August 22 and October 2, 2007. The HyMap data were converted to apparent surface reflectance, then further empirically adjusted using ground-based reflectance measurements. The reflectance spectrum of each pixel of HyMap data was compared to the spectral features of reference entries in a spectral library of minerals, vegetation, water, ice, and snow. This map shows the spatial distribution of iron-bearing minerals and other materials having diagnostic absorptions at visible and near-infrared wavelengths. These absorptions result from electronic processes in the minerals. Several criteria, including (1) the reliability of detection and discrimination of minerals using the HyMap spectrometer data, (2) the relative abundance of minerals, and (3) the importance of particular minerals to studies of Afghanistan's natural resources, guided the selection of entries in the reference spectral library and, therefore, guided the selection of mineral classes shown on this map. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated. Minerals having similar spectral features were less easily discriminated, especially where the minerals were not particularly abundant and (or) where vegetation cover reduced the absorption strength of mineral features. Complications in reflectance calibration also affected the detection and identification of minerals.

  14. Iron oxyhydroxide nanorods with high electrochemical reactivity as a sensitive and rapid determination platform for 4-chlorophenol

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuanyuan [Key Laboratory for Material Chemistry of Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Britton Chance Center for Biomedical Photonics at Wuhan, National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Cheng, Qin; Zheng, Meng [Key Laboratory for Material Chemistry of Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Liu, Xin [Britton Chance Center for Biomedical Photonics at Wuhan, National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Wu, Kangbing, E-mail: kbwu@hust.edu.cn [Key Laboratory for Material Chemistry of Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2016-04-15

    Highlights: • Prepared FeOOH nanorods exhibited high reactivity toward the oxidation of 4-CP. • Response signals and detection sensitivity of 4-CP increased greatly by FeOOH. • Highly-sensitive and rapid determination platform was developed for 4-CP. • Practical application in water samples was studied, and the accuracy was good. - Abstract: Iron oxyhydroxide (FeOOH) nanorods were prepared through solvothermal reaction, and characterized using Raman spectroscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy and scanning electron microscopy. Thereafter, the prepared FeOOH nanorods were used as sensing material to construct a novel detection platform for 4-chlorophenol (4-CP). The electrochemical behaviors of 4-CP were studied, and the oxidation peak currents increased greatly on the surface of FeOOH nanorods. The signal enhancement mechanism was studied for 4-CP, and it was found that the prepared FeOOH nanorods remarkably improved the electron transfer ability and surface adsorption efficiency of 4-CP. The influences of pH value, amount of FeOOH nanorods and accumulation time were examined. As a result, a highly-sensitive electrochemical method was developed for the rapid determination of 4-CP. The linear range was from 10 to 500 nM, and the detection limit was 3.2 nM. It was used in different water samples, and the results consisted with the values that obtained by high-performance liquid chromatography.

  15. Superhydrophobic surface fabricated on iron substrate by black chromium electrodeposition and its corrosion resistance property

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bo [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Key Lab of Comprehensive and Highly Efficient Utilization of Salt Lake Resource, Chinese Academy of Science, Xining 810008, Qinghai (China); Feng, Haitao [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai (China); Key Lab of Comprehensive and Highly Efficient Utilization of Salt Lake Resource, Chinese Academy of Science, Xining 810008, Qinghai (China); Lin, Feng [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Yabin [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai (China); Key Lab of Comprehensive and Highly Efficient Utilization of Salt Lake Resource, Chinese Academy of Science, Xining 810008, Qinghai (China); Wang, Liping [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Dong, Yaping [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai (China); Key Lab of Comprehensive and Highly Efficient Utilization of Salt Lake Resource, Chinese Academy of Science, Xining 810008, Qinghai (China); Li, Wu, E-mail: liwu2016@126.com [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, Qinghai (China); Key Lab of Comprehensive and Highly Efficient Utilization of Salt Lake Resource, Chinese Academy of Science, Xining 810008, Qinghai (China)

    2016-08-15

    Highlights: • Superhydrophobic surface was fabricated by black chromium electrodeposition and stearic acid modification. • The reaction process is simple, and of low cost, and no special instrument or environment is needed. • The obtained superhydrophobic surface presents good water repellency, and performs well at corrosion resistance. - Abstract: The fabrication of superhydrophobic surface on iron substrate is carried out through 20 min black chromium electrodeposition, followed by immersing in 0.05 M ethanolic stearic acid solution for 12 h. The resultant superhydrophobic complex film is characterized by scanning electron microscope (SEM), disperse Spectrometer (EDS), atomic force microscope (AFM), water contact angle (CA), sliding angle (SA) and X-ray photoelectron spectroscope (XPS), and its corrosion resistance property is measured with cyclic voltammetry (CV), linear polarization and electrochemical impedance spectroscopy (EIS). The results show that the fabricated superhydrophobic film has excellent water repellency (CA, 158.8°; SA, 2.1°) and significantly high corrosion resistance (1.31 × 10{sup 6} Ω cm{sup −2}) and excellent corrosion protection efficiency (99.94%).

  16. Temperature dependence of coercivity behavior in iron films on silicone oil surfaces

    International Nuclear Information System (INIS)

    Xu Xiaojun; Ye Quanlin; Ye Gaoxiang

    2007-01-01

    A new iron film system, deposited on silicone oil surfaces by vapor phase deposition method, has been fabricated and its microstructure as well as magnetic properties has been studied. It is found that the temperature dependence of the coercive field H c (T) of the films exhibits a peak around a critical temperature T crit =10-15 K: for the temperature T crit ,H c (T) increases with the temperature; if T>T crit , however, it decreases rapidly and then approaches a steady value as T further increases. Our study shows that, for T>T crit , the observed coercivity behavior is mainly dominated by the effect of the non-uniform single-domain particle size distribution, and for T crit , the anomalous coercivity behavior may be resulted from the surface anisotropy, the surface effect and the characteristic internal stress distribution in the films. The influence of the shape and size of the particles on the thermal dependence of the magnetization is also investigated

  17. Photoemission study of metallic iron nanoparticles surface aging in biological fluids. Influence on biomolecules adsorption

    International Nuclear Information System (INIS)

    Canivet, L.; Denayer, F.O.; Champion, Y.; Cenedese, P.; Dubot, P.

    2014-01-01

    Iron nanoparticles (nFe) prepared by vaporization and cryogenic condensation process (10–100 nm) has been exposed to Hank's balanced salt solution (HBSS) and the B-Ali cell growth fluids. These media can be used for cellular growth to study nFe penetration through cell membrane and its induced cytotoxicity. Surface chemistry of nFe exposed to such complex fluids has been characterized as the nanoparticles surface can be strongly changed by adsorption or corrosion processes before reaching intracellular medium. Particle size and surface chemistry have been characterized by scanning electron microscopy (SEM) and high-resolution X-ray photoelectron spectroscopy (HR-XPS). Exposition of nFe particles to growth and differentiation media leads to the formation of an oxy-hydroxide layer containing chlorinated species. We found that the passivated Fe 2 O 3 layer of the bare nFe particles is rapidly transformed into a thicker oxy-hydroxide layer that has a greater ability to adsorb molecular ions or ionic biomolecules like proteins or DNA.

  18. Photoemission study of metallic iron nanoparticles surface aging in biological fluids. Influence on biomolecules adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Canivet, L.; Denayer, F.O. [Université de Lille 2, Droit et Santé, 42 rue P. Duez, 59000 Lille (France); Champion, Y.; Cenedese, P. [CNRS-ICMPE, 2 rue H. Dunant, 94320 Thiais (France); Dubot, P., E-mail: pdubot@icmpe.cnrs.fr [CNRS-ICMPE, 2 rue H. Dunant, 94320 Thiais (France)

    2014-07-01

    Iron nanoparticles (nFe) prepared by vaporization and cryogenic condensation process (10–100 nm) has been exposed to Hank's balanced salt solution (HBSS) and the B-Ali cell growth fluids. These media can be used for cellular growth to study nFe penetration through cell membrane and its induced cytotoxicity. Surface chemistry of nFe exposed to such complex fluids has been characterized as the nanoparticles surface can be strongly changed by adsorption or corrosion processes before reaching intracellular medium. Particle size and surface chemistry have been characterized by scanning electron microscopy (SEM) and high-resolution X-ray photoelectron spectroscopy (HR-XPS). Exposition of nFe particles to growth and differentiation media leads to the formation of an oxy-hydroxide layer containing chlorinated species. We found that the passivated Fe{sub 2}O{sub 3} layer of the bare nFe particles is rapidly transformed into a thicker oxy-hydroxide layer that has a greater ability to adsorb molecular ions or ionic biomolecules like proteins or DNA.

  19. Using Iron-Manganese Co-Oxide Filter Film to Remove Ammonium from Surface Water.

    Science.gov (United States)

    Zhang, Ruifeng; Huang, Tinglin; Wen, Gang; Chen, Yongpan; Cao, Xin; Zhang, Beibei

    2017-07-19

    An iron-manganese co-oxide filter film (MeO x ) has been proven to be a good catalyst for the chemical catalytic oxidation of ammonium in groundwater. Compared with groundwater, surface water is generally used more widely and has characteristics that make ammonium removal more difficult. In this study, MeO x was used to remove ammonium from surface water. It indicated that the average ammonium removal efficiency of MeO x was greater than 90%, even though the water quality changed dramatically and the water temperature was reduced to about 6-8 °C. Then, through inactivating microorganisms, it showed that the removal capability of MeO x included both biological (accounted for about 41.05%) and chemical catalytic oxidation and chemical catalytic oxidation (accounted for about 58.95%). The investigation of the characterizations suggested that MeO x was formed by abiotic ways and the main elements on the surface of MeO x were distributed homogenously. The analysis of the catalytic oxidation process indicated that ammonia nitrogen may interact with MeO x as both ammonia molecules and ammonium ions and the active species of O₂ were possibly • O and O₂ - .

  20. Effects of blending of desalinated and conventionally treated surface water on iron corrosion and its release from corroding surfaces and pre-existing scales.

    Science.gov (United States)

    Liu, Haizhou; Schonberger, Kenneth D; Peng, Ching-Yu; Ferguson, John F; Desormeaux, Erik; Meyerhofer, Paul; Luckenbach, Heidi; Korshin, Gregory V

    2013-07-01

    This study examined effects of blending desalinated water with conventionally treated surface water on iron corrosion and release from corroding metal surfaces and pre-existing scales exposed to waters having varying fractions of desalinated water, alkalinities, pH values and orthophosphate levels. The presence of desalinated water resulted in markedly decreased 0.45 μm-filtered soluble iron concentrations. However, higher fractions of desalinated water in the blends were also associated with more fragile corroding surfaces, lower retention of iron oxidation products and release of larger iron particles in the bulk water. SEM, XRD and XANES data showed that in surface water, a dense layer of amorphous ferrihydrite phase predominated in the corrosion products. More crystalline surface phases developed in the presence of desalinated water. These solid phases transformed from goethite to lepidocrocite with increased fraction of desalinated water. These effects are likely to result from a combination of chemical parameters, notably variations of the concentrations of natural organic matter, calcium, chloride and sulfate when desalinated and conventionally treated waters are blended. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. A study on the fabrication of superhydrophobic iron surfaces by chemical etching and galvanic replacement methods and their anti-icing properties

    Science.gov (United States)

    Li, Kunquan; Zeng, Xingrong; Li, Hongqiang; Lai, Xuejun

    2015-08-01

    Hierarchical structures on iron surfaces were constructed by means of chemical etching by hydrochloric acid (HCl) solution or the galvanic replacement by silver nitrate (AgNO3) solution. The superhydrophobic iron surfaces were successfully prepared by subsequent hydrophobic modification with stearic acid. The superhydrophobic iron surfaces were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and water contact angle (WCA). The effects of reactive concentration and time on the microstructure and the wetting behavior were investigated. In addition, the anti-icing properties of the superhydrophobic iron surfaces were also studied. The FTIR study showed that the stearic acid was chemically bonded onto the iron surface. With the HCl concentration increase from 4 mol/L to 8 mol/L, the iron surface became rougher with a WCA ranging from 127° to 152°. The AgNO3 concentration had little effect on the wetting behavior, but a high AgNO3 concentration caused Ag particle aggregates to transform from flower-like formations into dendritic crystals, owing to the preferential growth direction of the Ag particles. Compared with the etching method, the galvanic replacement method on the iron surface more favorably created roughness required for achieving superhydrophobicity. The superhydrophobic iron surface showed excellent anti-icing properties in comparison with the untreated iron. The icing time of water droplets on the superhydrophobic surface was delayed to 500 s, which was longer than that of 295 s for untreated iron. Meanwhile, the superhydrophobic iron surface maintained superhydrophobicity after 10 icing and de-icing cycles in cold conditions.

  2. Determination of plutonium by secondary coulometric titration with internally generated iron(II) Pt. 2

    International Nuclear Information System (INIS)

    Chitnis, R.T.; Talnikar, S.G.; Thakur, V.A.; Paranjape, A.H.

    1979-01-01

    Determination of plutonium by secondary coulometry involving the controlled potential technique for the generation of an iron(II) mediator, is reported in Part I. In this paper, the same determination is reported using constant current coulometry for the generation of the mediator, and zero current potentiometry for end-point detection. The factors affecting the current efficiency, viz. current density and supporting electrolyte composition have been checked in order to define the appropriate conditions for obtaining 100% current efficiency. The original method of Carson et al. suffers from the disadvantage that it involves complicated sample treatment. Introduction of perchloric acid treatment as a method for the oxidation of plutonium and the pretitration of the supporting electrolyte to the end-point potential prior to sample addition, have considerably helped to improve the precision and accuracy of the method. Exhaustive analytical data are reported covering plutonium quantities ranging from 25 micrograms to 5 milligrams, which establishes the scope of the method. (author)

  3. Type I and type II residual stress in iron meteorites determined by neutron diffraction measurements

    Science.gov (United States)

    Caporali, Stefano; Pratesi, Giovanni; Kabra, Saurabh; Grazzi, Francesco

    2018-04-01

    In this work we present a preliminary investigation by means of neutron diffraction experiment to determine the residual stress state in three different iron meteorites (Chinga, Sikhote Alin and Nantan). Because of the very peculiar microstructural characteristic of this class of samples, all the systematic effects related to the measuring procedure - such as crystallite size and composition - were taken into account and a clear differentiation in the statistical distribution of residual stress in coarse and fine grained meteorites were highlighted. Moreover, the residual stress state was statistically analysed in three orthogonal directions finding evidence of the existence of both type I and type II residual stress components. Finally, the application of von Mises approach allowed to determine the distribution of type II stress.

  4. Size-controlled synthesis of superparamagnetic iron oxide nanoparticles and their surface coating by gold for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Maleki, H. [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Simchi, A., E-mail: simchi@sharif.edu [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Department of Material Science and Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Imani, M. [Novel Drug Delivery Systems Department, Iran Polymer and Petrochemical Institute, Tehran (Iran, Islamic Republic of); Costa, B.F.O. [CEMDRX, Department of Physics, University of Coimbra, P-3004-516 Coimbra (Portugal)

    2012-11-15

    The size mono-dispersity, saturation magnetization, and surface chemistry of magnetic nanoparticles (NPs) are recognized as critical factors for efficient biomedical applications. Here, we performed modified water-in-oil inverse nano-emulsion procedure for preparation of stable colloidal superparamagnetic iron oxide NPs (SPIONs) with high saturation magnetization. To achieve mono-dispersed SPIONs, optimization process was probed on several important factors including molar ratio of iron salts [Fe{sup 3+} and Fe{sup 2+}], the concentration of ammonium hydroxide as reducing agent, and molar ratio of water to surfactant. The biocompatibility of the obtained NPs, at various concentrations, was evaluated via MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay and the results showed that the NPs were non-toxic at concentrations <0.1 mg/mL. Surface functionalization was performed by conformal coating of the NPs with a thin shell of gold ({approx}4 nm) through chemical reduction of attached gold salts at the surface of the SPIONs. The Fe{sub 3}O{sub 4} core/Au shell particles demonstrate strong plasmon resonance absorption and can be separated from solution using an external magnetic field. Experimental data from both physical and chemical determinations of the changes in particle size, surface plasmon resonance optical band, phase components, core-shell surface composition, and magnetic properties have confirmed the formation of the mono-dispersed core-shell nanostructure. - Highlights: Black-Right-Pointing-Pointer Increasing the concentration of iron salts, cubic-shape SPION NPs were formed. The magnetic saturation of the SPIONs was also increased. Black-Right-Pointing-Pointer The concentration of reducing agent exhibited marginal effect on the size of SPIONs but influenced the crystallinity of the NPs. A lower magnetic saturation was obtained at higher NH{sub 4}OH concentrations. Black-Right-Pointing-Pointer Mono-dispersed SPIONs can be prepared

  5. ULTRASOUND PRETREATMENT OF ELEMENTAL IRON: KINETIC STUDIES OF DEHALOGENATION REACTION ENHANCEMENT AND SURFACE EFFECTS. (R828598C743)

    Science.gov (United States)

    This work presents data showing the kinetic improvement afforded by ultrasound pretreatment and illustrates the physical and chemical changes that take place at the iron surface. First-order rate constants improved as much as 78% with 2 h of ultrasound pretreatment. Scann...

  6. Experimental determination of the thermal contact conductance between two solid surfaces by the energy pulse technique

    International Nuclear Information System (INIS)

    Rubin, Gerson Antonio

    1979-01-01

    An experimental procedure for the determination of the thermal contact conductance between two solid surfaces as a function of the contact pressure and the energy of the laser radiation has been developed using the laser pulse method. A rubi laser with variable energy levels was employed as a radiating pulse energy source. The laser beam was allowed to impinge perpendicularly on the front face of a electrolytic iron 73 4 . The temperature fluctuations resulting on the back surface of the sample was detected by a thermocouple, which Is coupled to a PDP-11/45 Computer 32 Kbytes of memory, through a Analog-Digital Converter. A theoretical function, derived exclusively for the problem mentioned in this work, was adjusted by a method of least square fitting of experimental results. This adjustment yielded the value of a parameter related to the contact conductance between two surfaces. The experimental error obtained for the thermal contact conductance was +- 4.9%. (author)

  7. Fermi Surface with Dirac Fermions in CaFeAsF Determined via Quantum Oscillation Measurements

    Directory of Open Access Journals (Sweden)

    Taichi Terashima

    2018-02-01

    Full Text Available Despite the fact that 1111-type iron arsenides hold the record transition temperature of iron-based superconductors, their electronic structures have not been studied much because of the lack of high-quality single crystals. In this study, we comprehensively determine the Fermi surface in the antiferromagnetic state of CaFeAsF, a 1111 iron-arsenide parent compound, by performing quantum oscillation measurements and band-structure calculations. The determined Fermi surface consists of a symmetry-related pair of Dirac electron cylinders and a normal hole cylinder. From analyses of quantum-oscillation phases, we demonstrate that the electron cylinders carry a nontrivial Berry phase π. The carrier density is of the order of 10^{-3} per Fe. This unusual metallic state with the extremely small carrier density is a consequence of the previously discussed topological feature of the band structure which prevents the antiferromagnetic gap from being a full gap. We also report a nearly linear-in-B magnetoresistance and an anomalous resistivity increase above about 30 T for B∥c, the latter of which is likely related to the quantum limit of the electron orbit. Intriguingly, the electrical resistivity exhibits a nonmetallic temperature dependence in the paramagnetic tetragonal phase (T>118  K, which may suggest an incoherent state. Our study provides a detailed knowledge of the Fermi surface in the antiferromagnetic state of 1111 parent compounds and moreover opens up a new possibility to explore Dirac-fermion physics in those compounds.

  8. A method for the determination of ascorbic acid using the iron(II)-pyridine-dimethylglyoxime complex

    Energy Technology Data Exchange (ETDEWEB)

    Arya, S. P.; Mahajan, M. [Haryana, Kurukshetra Univ. (India). Dept. of Chemistry

    1998-05-01

    A simple and rapid spectrophotometric method for the determination of ascorbic acid is proposed. Ascorbic acid reduces iron (III) to iron (II) which forms a red colored complex with dimethylglyoxime in the presence of pyridine. The absorbance of the resulting solution is measured at 514 nm and a linear relationship between absorbance and concentration of ascorbic acid is observed up to 14 {mu}g ml{sup -1}. Studies on the interference of substances usually associated with ascorbic acid have been carried out and the applicability of the method has been tested by analysing pharmaceutical preparations of vitamin C. [Italiano] Si propone un rapido e semplice metodo spettrofotometrico per la determinazione dell`acido ascorbico. L`acido ascorbico riduce il ferro(III) a ferro(II) che forma con la dimetilgliossima, in presenza di piridina, un complesso colorato in rosso. L`assorbanza della soluzione risultante e` misurata a 514 nm e si ottiene una relazione lineare tra assorbanza e concentrazione dell`acido ascorbico fino a 14 {mu}g ml{sup -1}. Si sono condotti studi sugli interferenti usualmente associati all`acido ascorbico ed e` stata valutata l`applicabilita` del metodo all`analisi di preparati farmaceutici di vitamina C.

  9. Cost Surface-Derived Least-Cost Paths: A Case Study from Iron Age Orkney

    Directory of Open Access Journals (Sweden)

    Brian Rahn

    2005-12-01

    Full Text Available In recent years, GIS landscape models have begun to move towards more sophisticated techniques for representing the land surface in order to analyse site territories, pathways and travel costs. Many of the major commercial GIS packages now offer the ability to generate anisotropic cost surfaces. In addition, recent papers have proposed methodologies for generating cost surfaces to model social preferences affecting travel (Lee and Stucky 1998; Llobera 2000. In terms of practical applications, however, GIS models of catchment areas and paths between sites continue to be dominated by those constructed on the basis of slope alone. In parallel with this, regional analyses of site location, with few exceptions, have been undertaken either within large land masses, largely ignoring the effects of rivers, lakes and the sea on travel costs and affordances, or within single islands, neglecting travel to other neighbouring islands or the mainland. The reasons for this appear to be twofold: first, there is little information available on travel costs and travel rates using pre-industrial transportation technology, beyond very general statements; second, critical analysis of what constitutes an 'acceptable' travel distance is lacking, especially in situations where both water and land transport are possibilities. This article presents some preliminary results from a research project examining the location and distribution of Middle Iron Age sites (brochs in the landscape of Orkney, Northern Scotland. It employs a terrain model, taking into account differing friction values for land and water surfaces, as well as the nature of the shoreline (cliffs, beaches and how this affects access from land to sea and vice versa. It also attempts to model pathways between sites following three friction models: lowest-energy, lowest-visibility (hidden and highest-visibility (exposed.

  10. High-temperature superconductivity from fine-tuning of Fermi-surface singularities in iron oxypnictides

    Science.gov (United States)

    Charnukha, A.; Evtushinsky, D. V.; Matt, C. E.; Xu, N.; Shi, M.; Büchner, B.; Zhigadlo, N. D.; Batlogg, B.; Borisenko, S. V.

    2015-12-01

    In the family of the iron-based superconductors, the REFeAsO-type compounds (with RE being a rare-earth metal) exhibit the highest bulk superconducting transition temperatures (Tc) up to 55 K and thus hold the key to the elusive pairing mechanism. Recently, it has been demonstrated that the intrinsic electronic structure of SmFe0.92Co0.08AsO (Tc = 18 K) is highly nontrivial and consists of multiple band-edge singularities in close proximity to the Fermi level. However, it remains unclear whether these singularities are generic to the REFeAsO-type materials and if so, whether their exact topology is responsible for the aforementioned record Tc. In this work, we use angle-resolved photoemission spectroscopy (ARPES) to investigate the inherent electronic structure of the NdFeAsO0.6F0.4 compound with a twice higher Tc = 38 K. We find a similarly singular Fermi surface and further demonstrate that the dramatic enhancement of superconductivity in this compound correlates closely with the fine-tuning of one of the band-edge singularities to within a fraction of the superconducting energy gap Δ below the Fermi level. Our results provide compelling evidence that the band-structure singularities near the Fermi level in the iron-based superconductors must be explicitly accounted for in any attempt to understand the mechanism of superconducting pairing in these materials.

  11. Grafting of diazonium salts on oxides surface: formation of aryl-O bonds on iron oxide nanoparticles

    International Nuclear Information System (INIS)

    Brymora, Katarzyna; Fouineau, Jonathan; Eddarir, Asma; Chau, François; Yaacoub, Nader; Grenèche, Jean-Marc; Pinson, Jean; Ammar, Souad; Calvayrac, Florent

    2015-01-01

    Combining ab initio modeling and 57 Fe Mössbauer spectrometry, we characterized the nature of the chemical linkage of aminoalkyl arenediazonium salt on the surface of iron oxide nanoparticles. We established that it is built through a metal–oxygen–carbon bonding and not a metal–carbon one, as usually suggested and commonly observed in previously studied metal- or carbon-based surfaces

  12. Grafting of diazonium salts on oxides surface: formation of aryl-O bonds on iron oxide nanoparticles

    Science.gov (United States)

    Brymora, Katarzyna; Fouineau, Jonathan; Eddarir, Asma; Chau, François; Yaacoub, Nader; Grenèche, Jean-Marc; Pinson, Jean; Ammar, Souad; Calvayrac, Florent

    2015-11-01

    Combining ab initio modeling and 57Fe Mössbauer spectrometry, we characterized the nature of the chemical linkage of aminoalkyl arenediazonium salt on the surface of iron oxide nanoparticles. We established that it is built through a metal-oxygen-carbon bonding and not a metal-carbon one, as usually suggested and commonly observed in previously studied metal- or carbon-based surfaces.

  13. Grafting of diazonium salts on oxides surface: formation of aryl-O bonds on iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Brymora, Katarzyna [LUNAM Université du Maine, IMMM UMR CNRS 6283 (France); Fouineau, Jonathan; Eddarir, Asma; Chau, François [Université Paris Diderot, Sorbonne Paris Cité, ITODYS CNRS UMR 7086 (France); Yaacoub, Nader; Grenèche, Jean-Marc [LUNAM Université du Maine, IMMM UMR CNRS 6283 (France); Pinson, Jean; Ammar, Souad [Université Paris Diderot, Sorbonne Paris Cité, ITODYS CNRS UMR 7086 (France); Calvayrac, Florent, E-mail: florent.calvayrac@univ-lemans.fr [LUNAM Université du Maine, IMMM UMR CNRS 6283 (France)

    2015-11-15

    Combining ab initio modeling and {sup 57}Fe Mössbauer spectrometry, we characterized the nature of the chemical linkage of aminoalkyl arenediazonium salt on the surface of iron oxide nanoparticles. We established that it is built through a metal–oxygen–carbon bonding and not a metal–carbon one, as usually suggested and commonly observed in previously studied metal- or carbon-based surfaces.

  14. Multisensor system for determination of iron(II), iron(III), uranium(VI) and uranium(IV) in complex solutions

    International Nuclear Information System (INIS)

    Legin, A.V.; Seleznev, B.L.; Rudnitskaya, A.M.; Vlasov, Yu.G.; Tverdokhlebov, S.V.; Mack, B.; Abraham, A.; Arnold, T.; Baraniak, L.; Nitsche, H.

    1999-01-01

    Development and analytical evaluation of a multisensor system based on the principles of 'electronic tongue' for the determination of low contents of uranium(VI), uranium(IV), iron(II) and iron(III) in complex aqueous media have been carried out. A set of 29 different chemical sensors on the basis of all- solid-state crystalline and vitreous materials with enhanced electronic conductivity and redox and ionic cross-sensitivity have been incorporated into the sensor array. Multidimensional data have been processed by pattern recognition methods such as artificial neural networks and partial least squares. It has been demonstrated that Fe(II) and Fe(III) contents in the range from 10 -7 to 10 -4 mol L -1 of total iron concentration can be determined with the average precision of about 25 %. U(VI) and U(IV) contents can been determined with the average precision of 10-40% depending on the concentration. The developed multisensor system can be applied in future for the analysis of mining and borehole waters as well other contaminated natural media, including on-site measurements. (author)

  15. Effect of surface functionalisation on the interaction of iron oxide nanoparticles with polymerase chain reaction.

    Science.gov (United States)

    Aysan, Ayse Beyza; Knejzlík, Zdeněk; Ulbrich, Pavel; Šoltys, Marek; Zadražil, Aleš; Štěpánek, František

    2017-05-01

    The combination of nanoparticles with the polymerase chain reaction (PCR) can have benefits such as easier sample handling or higher sensitivity, but also drawbacks such as loss of colloidal stability or inhibition of the PCR. The present work systematically investigates the interaction of magnetic iron oxide nanoparticles (MIONs) with the PCR in terms of colloidal stability and potential PCR inhibition due to interaction between the PCR components and the nanoparticle surface. Several types of MIONs with and without surface functionalisation by sodium citrate, dextran and 3-aminopropyl-triethoxysilane (APTES) were prepared and characterised by Transmission Electron Microscopy (TEM), dynamic light scattering (DLS) and Fourier Transform Infrared (FT-IR) spectroscopy. Colloidal stability in the presence of the PCR components was investigated both at room temperature and under PCR thermo-cycling. Dextran-stabilized MIONs show the best colloidal stability in the PCR mix at both room and elevated temperatures. Citrate- and APTES-stabilised as well as uncoated MIONs show a comparable PCR inhibition near the concentration 0.1mgml -1 while the inhibition of dextran stabilized MIONs became apparent near 0.5mgml -1 . It was demonstrated that the PCR could be effectively carried out even in the presence of elevated concentration of MIONs up to 2mgml -1 by choosing the right coating approach and supplementing the reaction mix by critical components, Taq DNA polymerase and Mg 2+ ions. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Control of the interparticle spacing in superparamagnetic iron oxide nanoparticle clusters by surface ligand engineering

    Science.gov (United States)

    Dan, Wang; Bingbing, Lin; Taipeng, Shen; Jun, Wu; Fuhua, Hao; Chunchao, Xia; Qiyong, Gong; Huiru, Tang; Bin, Song; Hua, Ai

    2016-07-01

    Polymer-mediated self-assembly of superparamagnetic iron oxide (SPIO) nanoparticles allows modulation of the structure of SPIO nanocrystal cluster and their magnetic properties. In this study, dopamine-functionalized polyesters (DA-polyester) were used to directly control the magnetic nanoparticle spacing and its effect on magnetic resonance relaxation properties of these clusters was investigated. Monodisperse SPIO nanocrystals with different surface coating materials (poly(ɛ-caprolactone), poly(lactic acid)) of different molecular weights containing dopamine (DA) structure (DA-PCL2k, DA-PCL1k, DA-PLA1k)) were prepared via ligand exchange reaction, and these nanocrystals were encapsulated inside amphiphilic polymer micelles to modulate the SPIO nanocrystal interparticle spacing. Small-angle x-ray scattering (SAXS) was applied to quantify the interparticle spacing of SPIO clusters. The results demonstrated that the tailored magnetic nanoparticle clusters featured controllable interparticle spacing providing directly by the different surface coating of SPIO nanocrystals. Systematic modulation of SPIO nanocrystal interparticle spacing can regulate the saturation magnetization (M s) and T 2 relaxation of the aggregation, and lead to increased magnetic resonance (MR) relaxation properties with decreased interparticle spacing. Project supported by the National Key Basic Research Program of China (Grant No. 2013CB933903), the National Key Technology R&D Program of China (Grant No. 2012BAI23B08), and the National Natural Science Foundation of China (Grant Nos. 20974065, 51173117, and 50830107).

  17. Electronic and magnetic coupling of iron and copper phthalocyanine to ferromagnetic Co(100) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Felix; Sauther, Jens; Lach, Stefan; Ziegler, Christiane [Department of Physics, University of Kaiserslautern, Erwin Schroedinger Str. 56, D-67663 Kaiserslautern (Germany); Ali, Ehesan; Oppeneer, Peter [Department of Physics and Materials Science, Box 530, Uppsala University, S-75121 Uppsala (Sweden)

    2009-07-01

    Metallo-phthalocyanines are organic semiconductors which show in certain cases promising magnetic properties, advertising them for use in organic spintronics. Here, copper (CuPc) and iron phthalocyanine (FePc) were grown on ultra thin layers of Co(100) substrates with well known highly spin-polarized electron injection capability. Photoelectron spectroscopy (XPS) reveals different interactions between the pyrolytic nitrogen atoms and the cobalt surface for the two phthalocyanines. The analysis of the different multiplet structures appearing for the nitrogen core levels in the submonolayer regime and UPS investigations of the valence band electronic structure of the Co dominated region near the Fermi level indicates a particularly electronic coupling and a rehybridisation of the molecular orbitals with the cobalt orbitals. In order to clarify the influence of the two different central atoms on the electronic- and subsequently the magnetic coupling to the Co substrate, theoretical calculations using the GGA and GGA+U methodologies on a structure of Fe/Cu-phthalocyanine adsorbed on a 3-layered cobalt surface were performed indicating a ferromagnetic coupling between FePc and Co.

  18. Effect of microstructure and surface features on wetting angle of a Fe-3.2 wt%C.E. cast iron with water

    Science.gov (United States)

    Riahi, Samira; Niroumand, Behzad; Dorri Moghadam, Afsaneh; Rohatgi, Pradeep K.

    2018-05-01

    In the present study, variation in surface wetting behavior of a hypoeutectic cast iron with its microstructural features and surface roughness was investigated. Samples with an identical composition, i.e. Fe-3.2 wt%C.E., and different microstructures (a gray cast iron with A-type flake graphite and a white cast iron) were fabricated by gravity casting of molten cast iron in a chill mold at different cooling rates. A variation of surface roughness was also developed by polishing, a four-stage electroetching and a four-stage mechanical abrading on the samples. Roughness and water contact angles of all surfaces were then measured. The surface roughness factor and the solid fraction in contact with water by the Wenzel and Cassie-Baxter contact models were also calculated and compared with the corresponding measured contact angles to find out which regime was active. Results indicated that the surface microstructure and the type of constituents present at the surface influenced the cast iron surface wettability and that it was possible to change the surface contact angle by modification of the surface microstructure. The mechanically abraded gray cast iron followed the Wenzel-type regime while the electroetched surfaces of gray cast iron exhibited a transition from Wenzel to Cassie-Baxter type regime. In white cast iron, the results indicated Wenzel type behavior in the electroetched samples while for the mechanically abraded samples, none of these two models could predict the wetting behavior. Furthermore, the wetting angles of both gray and white cast irons were measured after 1, 2, 3 and 4 weeks of air exposure. The results showed that the wetting angles of both samples increased to above 90° after one week of air exposure which was likely due to adsorption of low surface energy hydrocarbons on the surfaces.

  19. Use of near infrared correlation spectroscopy for quantitation of surface iron, absorbed water and stored electronic energy in a suite of Mars soil analog materials

    Science.gov (United States)

    Coyne, Lelia M.; Banin, Amos; Carle, Glenn; Orenberg, James; Scattergood, Thomas

    1989-01-01

    A number of questions concerning the surface mineralogy and the history of water on Mars remain unresolved using the Viking analyses and Earth-based telescopic data. Identification and quantitation of iron-bearing clays on Mars would elucidate these outstanding issues. Near infrared correlation analysis, a method typically applied to qualitative and quantitative analysis of individual constituents of multicomponent mixtures, is adapted here to selection of distinctive features of a small, highly homologous series of Fe/Ca-exchanged montmorillonites and several kalinites. Independently determined measures of surface iron, relative humidity and stored electronic energy were used as constituent data for linear regression of the constituent vs. reflectance data throughout the spectral region 0.68 to 2.5 micrometers. High correlations were found in appropriate regions for all three constituents, though that with stored energy is still considered tenuous. Quantitation was improved using 1st and 2nd derivative spectra. High resolution data over a broad spectral range would be required to quantitatively identify iron-bearing clays by remotely sensed reflectance.

  20. Energy dispersive x-ray fluorescence spectrometric determination of phosphorus, calcium, iron, zinc, and strontium in human bones

    International Nuclear Information System (INIS)

    Ohta, Akishige; Matsubayashi, Takashi; Itoman, Moritoshi

    1981-01-01

    Phosphorus, calcium, iron, zinc and strontium in a human bone extracted by surgery were determined by energy dispersive X-ray fluorescence spectrometry. The bone was decomposed with nitric acid, then diluted with water. A specific quantity of the solution was naturally dried on polyethylene film, and subjected to X-ray analysis. For determining the calibration curves in a mixture of phosphorus, calcium, iron, zinc and strontium, for the analysis of phosphorus and calcium, germanium was used as the secondary target and aluminum as the filter; and for the analysis of iron, zinc and strontium, molybdenum and molybdenum-aluminum were used, respectively. Consequently, the calibration curves were able to be obtained with high precision in the ranges from 5 to 500 μg of phosphorus, from 1 to 50 μg of calcium and from 0.1 to 1.0 μg of iron, zinc and strontium. In this way, in 1 mg of the human bone by wet weight, phosphorus, calcium, iron, zinc and strontium were able to be determined. (J.P.N.)

  1. Temporal fluctuations in grain size, organic materials and iron concentrations in intertidal surface sediment of San Francisco Bay

    Science.gov (United States)

    Thomson-Becker, E. A.; Luoma, S.N.

    1985-01-01

    The physical and chemical characteristics of the oxidized surface sediment in an estuary fluctuate temporally in response to physical forces and apparently-fluctuating inputs. These characteristics, which include grain size and concentrations of organic materials and iron, will influence both trace-metal geochemistry and bioavailability. Temporal trends in the abundance of fine particles, total organic carbon content (TOC), absorbance of extractable organic material (EOM), and concentration of extractable iron in the sediment of San Francisco Bay were assessed using data sets containing approximately monthly samples for periods of two to seven years. Changes in wind velocity and runoff result in monthly changes in the abundance of fine particles in the intertidal zone. Fine-grained particles are most abundant in the late fall/early winter when runoff is elevated and wind velocities are low; particles are coarser in the summer when runoff is low and wind velocities are consistently high. Throughout the bay, TOC is linearly related to fine particle abundance (r = 0.61). Temporal variability occurs in this relationship, as particles are poor in TOC relative to percent of fine particles in the early rainy season. Iron-poor particles also appear to enter the estuary during high runoff periods; while iron is enriched on particle surfaces in the summer. Concentrations of extractable iron and absorbance of EOM vary strongly from year to year. Highest absorbances of EOM occurred in the first year following the drought in 1976-77, and in 1982 and 1983 when river discharge was unusually high. Extractable-iron concentrations were also highest in 1976-77, but were very low in 1982 and 1983. ?? 1985 Dr W. Junk Publishers.

  2. Determination of Surface Fluxes Using a Bowen Ratio System

    African Journals Online (AJOL)

    USER

    Components of the surface fluxes of the energy balance equation were determined ... and vapour pressure in combination with point measurements of net .... approaches zero, then almost all the energy available is used in evapotranspiration.

  3. Iron prophylaxis during pregnancy -- how much iron is needed? A randomized dose- response study of 20-80 mg ferrous iron daily in pregnant women

    DEFF Research Database (Denmark)

    Milman, Nils; Bergholt, Thomas; Eriksen, Lisbeth

    2005-01-01

    To determine the lowest dose of iron preventative of iron deficiency and iron deficiency anemia in pregnancy.......To determine the lowest dose of iron preventative of iron deficiency and iron deficiency anemia in pregnancy....

  4. Fermi surface deformation in a simple iron-based superconductor, FeSe

    Science.gov (United States)

    Coldea, Amalia; Watson, Matthew; Kim, Timur; Haghighirad, Amir; McCollam, Alix; Hoesch, Moritz; Schofield, Andrew

    2015-03-01

    One of the outstanding problems in the field superconductivity is the identification of the normal state out of which superconductivity emerges. FeSe is one of the simplest and most intriguing iron-based superconductors, since in its bulk form it undergoes a structural transition before it becomes superconducting, whereas its single-layer form is believed to be a high-temperature superconductor. The nature of the structural transition, occurring in the absence of static magnetism, is rather unusual and how the electronic structure is stabilized by breaking of the rotational symmetry is the key to understand the superconductivity in bulk FeSe. Here we report angle-resolved photoemission spectroscopy measurements on FeSe that gives direct access to the band structure and orbital-dependent effects. We complement our studies on bulk FeSe with low-temperature angular-dependent quantum oscillation measurements using applied magnetic fields that are sufficiently strong to suppress superconductivity and reach the normal state. These studies reveal a strong deformation of Fermi surface through the structural transition driven by electronic correlations and orbital-dependent effects. . This work was supported by EPSRC, UK (EP/I004475/1), Diamond Light Source, UK and HFML, Nijmegen.

  5. Iron dissolution from volcanic ash in low-pH atmospheric water: a key control on volcanic iron input to the surface ocean?

    Science.gov (United States)

    Maters, E.; Delmelle, P.; Ayris, P. M.; Opfergelt, S.

    2012-12-01

    A low concentration of dissolved iron (Fe) limits phytoplankton growth in approximately 30% of the ocean. The input of soluble Fe to these High-Nutrient Low-Chlorophyll (HNLC) regions has the potential to boost primary production and thereby enhance the drawdown of atmospheric carbon dioxide (CO2). Over geological timescales, volcanic activity may alter the flux of Fe to the surface ocean and so contribute to modulating atmospheric CO2 concentrations, ultimately impacting the global climate. Ocean Fe fertilisation has also recently been found to contribute to century-scale carbon sequestration via the export of biomass to the seafloor. Atmospherically deposited volcanic ash is now increasingly seen as an intermittent source of Fe to the surface ocean. Understanding the process of Fe release from ash in solution is key for assessing the potential for ash, particularly that produced by large but rare explosive eruptions or during sustained periods of intense volcanism, to fertilise the marine environment. Previous studies have measured the release of Fe from ash in near-neutral pH solution, but the influence of interaction between ash and acidic cloud- or rainwater during transport on Fe release is poorly understood. In this study, seven volcanic ash samples ranging from tephrite to rhyolite (49-74 wt.% SiO2) were leached in pH 1 H2SO4 in batch reactors for 336 h, at a 1:500 ash-to-solution ratio, to investigate Fe release under acidic conditions. Major element concentrations were measured by inductively coupled plasma- atomic emission spectroscopy (ICP-AES) across a time series of ash leachates. Changes in ash surface composition induced by contact with acid solution were assessed by X-ray photoelectron spectroscopy (XPS). The Fe2+/Fe3+ ratio in ash leachates was also determined for the first time, using the Ferrozine method. The ash samples released 42 to 411 μmol m-2 of Fe over 336 h of leaching. High initial Fe release rates (>1 μmol m-2 h-1) sustained for up

  6. Determination of iron in highly-saline matrices by FIA-ICP-MS

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    Analysis of iron by inductively-coupled-plasma mass-spectrometry (ICP-MS) may be significantly improved by applying a protocol of flow-injection analysis. The iron species of the sample was preconcentrated by an ammonia buffer at pH = 9.2 on a filterless nylon-knotted reactor, and the adsorbed...... species were subsequently eluted by hydrochloric acid and analysed by ICP-MS. During the FIA step of preconcentration, a high degree of salinity did not influence the adsorption mechanism of iron, which may be related to formation of iron-hydroxide complexes at the sites of amide moieties of the nylon...

  7. Corrosion inhibition of Eleusine aegyptiaca and Croton rottleri leaf extracts on cast iron surface in 1 M HCl medium

    International Nuclear Information System (INIS)

    Rajeswari, Velayutham; Kesavan, Devarayan; Gopiraman, Mayakrishnan; Viswanathamurthi, Periasamy; Poonkuzhali, Kaliyaperumal; Palvannan, Thayumanavan

    2014-01-01

    Graphical abstract: - Highlights: • Eleusine aegyptiaca and Croton rottleri are commonly available, less-toxic and eco-friendly inhibitors for cast iron corrosion. • The active constituents present in extracts adsorbed on the iron surface to inhibit the acidic corrosion. • The higher values of E a and ΔH * point out the higher inhibition efficiency noticed for the inhibitors. • Weight loss methods at various temperature and spectral data provides evidence for adsorption mechanism of inhibitors. - Abstract: The adsorption and corrosion inhibition activities of Eleusine aegyptiaca (E. aegyptiaca) and Croton rottleri (C. rottleri) leaf extracts on cast iron corrosion in 1 M hydrochloric acid solution were studied first time by weight loss and electrochemical techniques viz., Tafel polarization and electrochemical impedance spectroscopy. The results obtained from the weight loss and electrochemical methods showed that the inhibition efficiency increased with inhibitor concentrations. It was found that the extracts acted as mixed-type inhibitors. The addition of halide additives (KCl, KBr, and KI) on the inhibition efficiency has also been investigated. The adsorption of the inhibitors on cast iron surface both in the presence and absence of halides follows the Langmuir adsorption isotherm model. The inhibiting nature of the inhibitors was supported by FT-IR, UV–vis, Wide-angle X-ray diffraction and SEM methods

  8. The impact of changing surface ocean conditions on the dissolution of aerosol iron

    Science.gov (United States)

    Fishwick, Matthew P.; Sedwick, Peter N.; Lohan, Maeve C.; Worsfold, Paul J.; Buck, Kristen N.; Church, Thomas M.; Ussher, Simon J.

    2014-11-01

    The proportion of aerosol iron (Fe) that dissolves in seawater varies greatly and is dependent on aerosol composition and the physicochemical conditions of seawater, which may change depending on location or be altered by global environmental change. Aerosol and surface seawater samples were collected in the Sargasso Sea and used to investigate the impact of these changing conditions on aerosol Fe dissolution in seawater. Our data show that seawater temperature, pH, and oxygen concentration, within the range of current and projected future values, had no significant effect on the dissolution of aerosol Fe. However, the source and composition of aerosols had the most significant effect on the aerosol Fe solubility, with the most anthropogenically influenced samples having the highest fractional solubility (up to 3.2%). The impact of ocean warming and acidification on aerosol Fe dissolution is therefore unlikely to be as important as changes in land usage and fossil fuel combustion. Our experimental results also reveal important changes in the size distribution of soluble aerosol Fe in solution, depending on the chemical conditions of seawater. Under typical conditions, the majority (77-100%) of Fe released from aerosols into ambient seawater existed in the colloidal (0.02-0.4 µm) size fraction. However, in the presence of a sufficient concentration of strong Fe-binding organic ligands (10 nM) most of the aerosol-derived colloidal Fe was converted to soluble Fe (<0.02 µm). This finding highlights the potential importance of organic ligands in retaining aerosol Fe in a biologically available form in the surface ocean.

  9. Genotoxicity assessment of magnetic iron oxide nanoparticles with different particle sizes and surface coatings

    International Nuclear Information System (INIS)

    Liu, Yanping; Xia, Qiyue; Liu, Ying; Zhang, Shuyang; Cheng, Feng; Wang, Li; Li, Hongxia; Xiao, Kai; Zhong, Zhihui

    2014-01-01

    Magnetic iron oxide nanoparticles (IONPs) have been widely used for various biomedical applications such as magnetic resonance imaging and drug delivery. However, their potential toxic effects, including genotoxicity, need to be thoroughly understood. In the present study, the genotoxicity of IONPs with different particle sizes (10, 30 nm) and surface coatings (PEG, PEI) were assessed using three standard genotoxicity assays, the Salmonella typhimurium reverse mutation assay (Ames test), the in vitro mammalian chromosome aberration test, and the in vivo micronucleus assay. In the Ames test, SMG-10 (PEG coating, 10 nm) showed a positive mutagenic response in all the five test bacterial strains with and without metabolic activation, whereas SEI-10 (PEI coating, 10 nm) showed no mutagenesis in all tester strains regardless of metabolic activation. SMG-30 (PEG coating, 30 nm) was not mutagenic in the absence of metabolic activation, and became mutagenic in the presence of metabolic activation. In the chromosomal aberration test, no increase in the incidence of chromosomal aberrations was observed for all three IONPs. In the in vivo micronucleus test, there was no evidence of increased micronuclei frequencies for all three IONPs, indicating that they were not clastogenic in vivo. Taken together, our results demonstrated that IONPs with PEG coating exhibited mutagenic activity without chromosomal and clastogenic abnormalities, and smaller IONPs (SMG-10) had stronger mutagenic potential than larger ones (SMG-30); whereas, IONPs with SEI coating (SEI-10) were not genotoxic in all three standard genotoxicity assays. This suggests that the mutagenicity of IONPs depends on their particle size and surface coating. (paper)

  10. Morphology and electronic structure of the oxide shell on the surface of iron nanoparticles.

    Science.gov (United States)

    Wang, Chongmin; Baer, Donald R; Amonette, James E; Engelhard, Mark H; Antony, Jiji; Qiang, You

    2009-07-01

    An iron (Fe) nanoparticle exposed to air at room temperature will be instantly covered by an oxide shell that is typically approximately 3 nm thick. The nature of this native oxide shell, in combination with the underlying Fe(0) core, determines the physical and chemical behavior of the core-shell nanoparticle. One of the challenges of characterizing core-shell nanoparticles is determining the structure of the oxide shell, that is, whether it is FeO, Fe(3)O(4), gamma-Fe(2)O(3), alpha-Fe(2)O(3), or something else. The results of prior characterization efforts, which have mostly used X-ray diffraction and spectroscopy, electron diffraction, and transmission electron microscopic imaging, have been framed in terms of one of the known Fe-oxide structures, although it is not necessarily true that the thin layer of Fe oxide is a known Fe oxide. In this Article, we probe the structure of the oxide shell on Fe nanoparticles using electron energy loss spectroscopy (EELS) at the oxygen (O) K-edge with a spatial resolution of several nanometers (i.e., less than that of an individual particle). We studied two types of representative particles: small particles that are fully oxidized (no Fe(0) core) and larger core-shell particles that possess an Fe core. We found that O K-edge spectra collected for the oxide shell in nanoparticles show distinct differences from those of known Fe oxides. Typically, the prepeak of the spectra collected on both the core-shell and the fully oxidized particles is weaker than that collected on standard Fe(3)O(4). Given the fact that the origin of this prepeak corresponds to the transition of the O 1s electron to the unoccupied state of O 2p hybridized with Fe 3d, a weak pre-edge peak indicates a combination of the following four factors: a higher degree of occupancy of the Fe 3d orbital; a longer Fe-O bond length; a decreased covalency of the Fe-O bond; and a measure of cation vacancies. These results suggest that the coordination configuration in

  11. High-precision determination of the isotopic composition of dissolved iron in iron depleted seawater by double spike multicollector-ICPMS.

    Science.gov (United States)

    Lacan, Francois; Radic, Amandine; Labatut, Marie; Jeandel, Catherine; Poitrasson, Franck; Sarthou, Geraldine; Pradoux, Catherine; Chmeleff, Jerome; Freydier, Remi

    2010-09-01

    This work demonstrates the feasibility of the measurement of the isotopic composition of dissolved iron in seawater for an iron concentration range, 0.05-1 nmol L(-1), allowing measurements in most oceanic waters, including Fe depleted waters of high nutrient low chlorophyll areas. It presents a detailed description of our previously published protocol, with significant improvements on detection limit and blank contribution. Iron is preconcentrated using a nitriloacetic acid superflow resin and purified using an AG 1-x4 anion exchange resin. The isotopic ratios are measured with a multicollector-inductively coupled plasma mass spectrometer (MC-ICPMS) Neptune, coupled with a desolvator (Aridus II or Apex-Q), using a (57)Fe-(58)Fe double spike mass bias correction. A Monte Carlo test shows that optimum precision is obtained for a double spike composed of approximately 50% (57)Fe and 50% (58)Fe and a sample to double spike quantity ratio of approximately 1. Total procedural yield is 91 +/- 25% (2SD, n = 55) for sample sizes from 20 to 2 L. The procedural blank ranges from 1.4 to 1.1 ng, for sample sizes ranging from 20 to 2 L, respectively, which, converted into Fe concentrations, corresponds to blank contributions of 0.001 and 0.010 nmol L(-1), respectively. Measurement precision determined from replicate measurements of seawater samples and standard solutions is 0.08 per thousand (delta(56)Fe, 2SD). The precision is sufficient to clearly detect and quantify isotopic variations in the oceans, which so far have been observed to span 2.5 per thousand and thus opens new perspectives to elucidate the oceanic iron cycle.

  12. Determination of iron sulphides in roofing slates from the north west of Spain

    Directory of Open Access Journals (Sweden)

    García-Guinea, J.

    2002-06-01

    Full Text Available The most important production of roofing slates in the world is quarried from the Ordovician formations of the Truchas Syncline, which have the largest amount of working quarries. Roofing slates, sometimes, have crystallized iron sulphides such as pyrite, pyrrhotite and other minerals. These iron sulphides oxidise and stain the tiles when are exposed to atmospheric conditions, so much oxidized how much more inclined is the roof. Galician quarrymen distinguish between harmless pyrite (i.e., resistant cubes of pyrite and damaging pyrite (i.e., other alterable metallic minerals such as pyrrhotite, chalcopyrite, marcasite and arsenopyirite. An improved identification method is proposed using both methods (a chemical element ratios of samples under electron microprobes and (b quantitative determination of the iron sulphides in the slate measuring the oxidized areas by digital camera. The analysed Fe/S ratios, in an XY plot, of seventy metallic samples, define three separated zones: pyrite, pyrrhotite and iron oxi-hydroxides. Quantitative determination of iron sulphides in the slate tile were performed by sinking the tile horizontally for six hours in oxygen peroxide (3% diluted and capturing the oxidation areas with a magnetic camera and analysing the bitmap images with Sigma-Scan 5 software. The proposed method is faster than the Spanish UNE norm (UNE-EN- 12326-2 Sept.2000, which requires thermal strike cycles for a month. The necessary use of heavy analytical equipment such as electron microprobes can be facilitated by installing it in the Slate Technological Centre of Sobradelo de Valdeorras (Orense or by using a simple optical stereoscopic zoom microscope to classify the iron minerals.

    Las formaciones ordovícicas del Sinclinal de Duchas concentran la mayor producción mundial de pizarra para cubiertas y el mayor número de canteras en producción. Las pizarras para cubiertas muchas veces contienen sulfuros de hierro cristalizados en forma

  13. Effects of striated laser tracks on thermal fatigue resistance of cast iron samples with biomimetic non-smooth surface

    International Nuclear Information System (INIS)

    Tong, Xin; Zhou, Hong; Liu, Min; Dai, Ming-jiang

    2011-01-01

    In order to enhance the thermal fatigue resistance of cast iron materials, the samples with biomimetic non-smooth surface were processed by Neodymium:Yttrium Aluminum Garnet (Nd:YAG) laser. With self-controlled thermal fatigue test method, the thermal fatigue resistance of smooth and non-smooth samples was investigated. The effects of striated laser tracks on thermal fatigue resistance were also studied. The results indicated that biomimetic non-smooth surface was benefit for improving thermal fatigue resistance of cast iron sample. The striated non-smooth units formed by laser tracks which were vertical with thermal cracks had the best propagation resistance. The mechanisms behind these influences were discussed, and some schematic drawings were introduced to describe them.

  14. Study of granitic biotites by X-ray fluorescence analysis: determination of iron, manganese, titanium, calcium, potassium, silicon and aluminium

    International Nuclear Information System (INIS)

    Toubes, R. O.; Bermudez Polonio, J.

    1968-01-01

    A method for the quantitative determination of iron, manganese, titanium, calcium potassium, silicon, and aluminium, is reported, Sample preparation is carried out by the miniature flux technique, and rubidium is used as internal standard for silicon and aluminium. (Author) 5 refs

  15. Determination of Non-Transferrin Bound Iron, Transferrin Bound Iron, Drug Bound Iron and Total Iron in Serum in a Rats after IV Administration of Sodium Ferric Gluconate Complex by Simple Ultrafiltration Inductively Coupled Plasma Mass Spectrometric Detection

    Directory of Open Access Journals (Sweden)

    Murali K. Matta

    2018-02-01

    Full Text Available A rapid, sensitive and specific ultrafiltration inductively-coupled plasma mass spectrometry method was developed and validated for the quantification of non-transferrin bound iron (NTBI, transferrin bound iron (TBI, drug bound iron (DI and total iron (TI in the same rat serum sample after intravenous (IV administration of iron gluconate nanoparticles in sucrose solution (Ferrlecit®. Ultrafiltration with a 30 kDa molecular cut-off filter was used for sample cleanup. Different elution solvents were used to separate each form of iron from sample serum. Isolated fractions were subjected to inductively-coupled mass spectrometric analysis after microwave digestion in 4% nitric acid. The reproducibility of the method was evaluated by precision and accuracy. The calibration curve demonstrated linearity from 5–500 ng/mL with a regression (r2 of more than 0.998. This method was effectively implemented to quantify rat pharmacokinetic study samples after intravenous administration of Ferrlecit®. The method was successfully applied to a pharmacokinetic (PK study of Ferrlecit in rats. The colloidal iron followed first order kinetics with half-life of 2.2 h and reached background or pre-dose levels after 12 h post-dosing. The drug shown a clearance of 0.31 mL/min/kg and volume of distribution of 0.05 L/kg. 19.4 ± 2.4 mL/h/kg.

  16. Determination of iron and copper contents in certain indigenous varieties of wheat (Triticum aestivum, L.)

    International Nuclear Information System (INIS)

    Akhtar, M.S.; Abbas, N.; Shaheen, A.

    2004-01-01

    Forty seven wheat varieties were tested for their iron and copper contents. The iron and copper contents were found to differ significantly (P 0.05) with respect to iron and copper contents. The variety named Dirk was found to possess the highest iron contents, while the variety Pasban-90 showed the highest copper contents. The varieties Dirk, Sariab, Tandojam-83, Punjab-88, Sarsabz, Punjab-81, Sandal and Sind-81 contained significantly higher iron contents as compared to other wheat varieties. The varieties, which contained the highest concentrations of copper, were Pasban-90, Chenab-79, Faisalabad-85, Lyp-73, Sind-81, Anmol-91, C-271, Rohtas-90 and Chakwal-86. However, the differences in copper contents among all these wheat varieties were non-significant (P>0.05). These varieties can therefore, be recommended to be included for future breeding and commercial exploitation. (author)

  17. Calibration equations for energy-dispersive XRF determination of copper, iron and lead in copper ore slurries

    International Nuclear Information System (INIS)

    Lakosz, M.

    1976-01-01

    Calibration equations for the X-ray fluorescence analysis determination of copper, iron and lead in copper ore slurries have been derived and tested. The measurement of Ksub(α) lines of copper and iron and Lsub(α) line of lead excited by rays from 238 Pu source have been used. Si/Li detector coupled to multichannel analyzer and minicomputer have been applied in measurements. The matrix and density effect have been eliminated by additional measurement of back-scattered primary radiation. (author)

  18. Environmental application of millimeter-scale sponge iron (s-Fe(0)) particles (II): the effect of surface copper.

    Science.gov (United States)

    Ju, Yongming; Liu, Xiaowen; Liu, Runlong; Li, Guohua; Wang, Xiaoyan; Yang, Yanyan; Wei, Dongyang; Fang, Jiande; Dionysiou, Dionysios D

    2015-04-28

    To enhance the catalytic reactivity of millimeter-scale particles of sponge iron (s-Fe(0)), Cu(2+) ions were deposited on the surface of s-Fe(0) using a simple direct reduction reaction, and the catalytic properties of the bimetallic system was tested for removal of rhodamine B (RhB) from an aqueous solution. The influence of Cu(0) loading, catalyst dosage, particle size, initial RhB concentration, and initial pH were investigated, and the recyclability of the catalyst was also assessed. The results demonstrate that the 3∼5 millimeter s-Fe(0) particles (s-Fe(0)(3∼5mm)) with 5wt% Cu loading gave the best results. The removal of RhB followed two-step, pseudo-first-order reaction kinetics. Cu(0)-s-Fe(0) showed excellent stability after five reuse cycles. Cu(0)-s-Fe(0) possesses great advantages compared to nanoscale zero-valent iron, iron power, and iron flakes as well as its bimetals. The surface Cu(0) apparently catalyzes the production of reactive hydrogen atoms for indirect reaction and generates Fe-Cu galvanic cells that enhance electron transfer for direct reaction. This bimetallic catalyst shows great potential for the pre-treatment of recalcitrant wastewaters. Additionally, some oxides containing iron element are selected to simulate the adsorption process. The results prove that the adsorption process of FeOOH, Fe2O3 and Fe3O4 played minor role for the removal of RhB. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Experimental Study of Removing Surface Corrosion Products from Archaeological Iron Objects and Alternating Iron Corrosion Products by Nd:YAG Laser Cleaning System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hye Youn; Cho, Nam Chul [Kongju National University, Daejeon (Korea, Republic of); Lee, Jong Myoung [IMT co. Ltd, Suwon (Korea, Republic of); Yu, Jae Eun [National Research Institute of Cultural Heritage, Daejeon (Korea, Republic of)

    2012-05-15

    The corrosion product of archaeological iron objects is supposed to be removed because it causes re-corrosion. So far it is removed by scapel and sand blaster but they depend on the skill and experience of a conservator and the glass-dust of the sand blaster is harmful to humans. Therefore this study applies a laser cleaning system which is used in various industrial cleaning processes, to remove corrosion product from archaeological iron objects. In addition, this work studies the alternation of corrosion product after laser irradiation, which evaluates the reliability of the laser cleaning system. Optical microscopy, SEM-EDS, XRD, Raman have been used to observe and analyse the surface of the objects. The results show the capacity of laser cleaning some corrosion product, but blackening appears with increasing pulses and laser energy, and some corrosion products, goethite and hematite, are partially altered to magnetite. These problems, blackening and alternation of corrosion product, should be solved by further studies which find the optimal laser irradiation condition and use a wetting agent.

  20. Distribution of iron and titanium on the lunar surface from lunar prospector gamma ray spectra

    International Nuclear Information System (INIS)

    Prettyman, T.H.; Feldman, W.C.; Lawrence, David J.; Elphic, R.C.; Gasnault, O.M.; Maurice, S.; Moore, K.R.; Binder, A.B.

    2001-01-01

    Gamma ray pulse height spectra acquired by the Lunar Prospector (LP) Gamma-Ray Spectrometer (GRS) contain information on the abundance of major elements in the lunar surface, including O, Si, Ti, Al, Fe, Mg, Ca, K, and Th. With the exception of Th and K, prompt gamma rays produced by cosmic ray interactions with surface materials are used to determine elemental abundance. Most of these gamma rays are produced by inelastic scattering of fast neutrons and by neutron capture. The production of neutron-induced gamma rays reaches a maximum deep below the surface (e.g. ∼140 g/cm 2 for inelastic scattering and ∼50 g/cm 2 for capture). Consequently, gamma rays sense the bulk composition of lunar materials, in contrast to optical methods (e.g. Clementine Spectral Reflectance (CSR)), which only sample the top few microns. Because most of the gamma rays are produced deep beneath the surface, few escape unscattered and the continuum of scattered gamma rays dominates the spectrum. In addition, due to the resolution of the spectrometer, there are few well-isolated peaks and peak fitting algorithms must be used to deconvolve the spectrum in order to determine the contribution of individual elements.

  1. Ultrasensitive and Fast Voltammetric Determination of Iron in Seawater by Atmospheric Oxygen Catalysis in 500 μL Samples.

    Science.gov (United States)

    Caprara, Salvatore; Laglera, Luis M; Monticelli, Damiano

    2015-06-16

    A new method based on adsorptive cathodic stripping voltammetry with catalytic enhancement for the determination of total dissolved iron in seawater is reported. It was demonstrated that iron detection at the ultratrace level (0.1 nM) may be achieved in small samples (500 μL) with high sensitivity, no need for purging, no added oxidant, and a limit of detection of 5 pM. The proposed method is based on the adsorption of the complex Fe/2,3-dihydroxynaphthalene (DHN) exploiting the catalytic effect of atmospheric oxygen. As opposite to the original method (Obata, H.; van den Berg, C. M. Anal. Chem. 2001, 73, 2522-2528), atmospheric oxygen dissolved in solution replaced bromate ions in the oxidation of the iron complex: removing bromate reduces the blank level and avoids the use of a carcinogenic species. Moreover, the new method is based on a recently introduced hardware that enables the determinations to be performed in 500 μL samples. The analyses were carried out on buffered samples (pH 8.15, HEPPS 0.01 M), 10 μM DHN and iron quantified by the standard addition method. The sensitivity is 49 nA nM(-1) min(-1) with 30 s deposition time and the LOD is equal to 5 pM. As a result, the whole procedure for the quantification of iron in one sample requires around 7.5 min. The new method was validated via analysis on two reference samples (SAFe S and SAFe D2) with low iron content collected in the North Pacific Ocean.

  2. Simple time-saving method for iron determination based on fluorescence quenching of an azaflavanon-3-ol compound.

    Science.gov (United States)

    Başoğlu, Aysel; Tosun, Gonca; Ocak, Miraç; Alp, Hakan; Yaylı, Nurettin; Ocak, Ümmühan

    2015-03-18

    A simple and time-saving spectrofluorometric method developed using an azaflavanon-3-ol compound was used for the determination of iron in various food samples. Nitric acid and hydrogen peroxide were used for digestion of samples in a closed microwave system. The method was validated by analyzing two certified reference materials (CRM-SA-C Sandy Soil C and Mixed Polish Herbs INCT-MPH-2). Measurements were carried out using a modified standard addition method. The standard addition graph was linear until 21.6 mg/L in the determination of iron(III). Detection and quantification limits were 0.81 and 2.4 mg/L, respectively. Satisfactory accuracy was obtained for spinach, dill, mint, purslane, rocket, red lentils, dry beans, and two iron medicinal tablets. High recoveries were found for streamwater samples fortified at three different concentrations. The method is simple, time-saving, cost-effective, and suitable for the determination of the iron content of foods.

  3. The Effect of Superparamagnetic Iron Oxide Nanoparticle Surface Charge on Antigen Cross-Presentation

    Science.gov (United States)

    Mou, Yongbin; Xing, Yun; Ren, Hongyan; Cui, Zhihua; Zhang, Yu; Yu, Guangjie; Urba, Walter J.; Hu, Qingang; Hu, Hongming

    2017-01-01

    Magnetic nanoparticles (NPs) of superparamagnetic iron oxide (SPIO) have been explored for different kinds of applications in biomedicine, mechanics, and information. Here, we explored the synthetic SPIO NPs as an adjuvant on antigen cross-presentation ability by enhancing the intracellular delivery of antigens into antigen presenting cells (APCs). Particles with different chemical modifications and surface charges were used to study the mechanism of action of antigen delivery. Specifically, two types of magnetic NPs, γFe2O3/APTS (3-aminopropyltrimethoxysilane) NPs and γFe2O3/DMSA (meso-2, 3-Dimercaptosuccinic acid) NPs, with the same crystal structure, magnetic properties, and size distribution were prepared. Then, the promotion of T-cell activation via dendritic cells (DCs) was compared among different charged antigen coated NPs. Moreover, the activation of the autophagy, cytosolic delivery of the antigens, and antigen degradation mediated by the proteasome and lysosome were measured. Our results indicated that positive charged γFe2O3/APTS NPs, but not negative charged γFe2O3/DMSA NPs, enhanced the cross-presentation ability of DCs. Increased cross-presentation ability induced by γFe2O3/APTS NPs was associated with increased cytosolic antigen delivery. On the contrary, γFe2O3/DMSA NPs was associated with rapid autophagy. Overall, our results suggest that antigen delivered in cytoplasm induced by positive charged particles is beneficial for antigen cross-presentation and T-cell activation. NPs modified with different chemistries exhibit diverse biological properties and differ greatly in their adjuvant potentials. Thus, it should be carefully considered many different effects of NPs to design effective and safe adjuvants.

  4. Application of Response Surface Methodology on Leaching of Iron from Partially Laterised Khondalite Rocks: A Bauxite Mining Waste

    Science.gov (United States)

    Swain, Ranjita; Bhima Rao, R.

    2018-04-01

    In the present investigation, response surface methodology (RSM) is used for a quadratic model that continuously controls the process parameters. This model is used to optimize the removal of iron oxide from Partially Laterised Khondalite (PLK) rocks which is influenced by several independent variables namely acid concentration, time and temperature. Second order response functions are produced for leaching of iron oxide from PLK rocks-a bauxite mining waste. In RSM, Box-Behnken design is used for the process optimization to achieve maximum removal of iron oxide. The influence of the process variables of leaching of iron oxide is presented in the form of 3-D response graphs. The results of this investigation reveals that 3 M hydrochloric acid concentration, 240 min time and 373 K temperature are found to be the best conditions for removal of 99% Fe2O3. The product obtain at this condition contain 80% brightness which is suitable for ceramic and filler industry applications. The novelity of the work is that the waste can be a value added product after suitable physical beneficiation and chemical treatment.

  5. Final Report: The Impact of Carbonate on Surface Protonation, Electron Transfer and Crystallization Reactions in Iron Oxide Nanoparticles and Colloids

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, David Adams [The University of Alabama

    2013-07-02

    This project addresses key issues of importance in the geochemical behavior of iron oxides and in the geochemical cycling of carbon and iron. For Fe, we are specifically studying the influence of carbonate on electron transfer reactions, solid phase transformations, and the binding of carbonate to reactive sites on the edges of particles. The emphasis on carbonate arises because it is widely present in the natural environment, is known to bind strongly to oxide surfaces, is reactive on the time scales of interest, and has a speciation driven by acid-base reactions. The geochemical behavior of carbonate strongly influences global climate change and CO{sub 2} sequestration technologies. Our goal is to answer key questions with regards to specific site binding, electron transfer reactions, and crystallization reactions of iron oxides that impact both the geochemical cycling of iron and CO{sub 2} species. Our work is focused on the molecular level description of carbonate chemistry in solution including the prediction of isotope fractionation factors. We have also done work on critical atmospheric species.

  6. Application of Response Surface Methodology on Leaching of Iron from Partially Laterised Khondalite Rocks: A Bauxite Mining Waste

    Science.gov (United States)

    Swain, Ranjita; Bhima Rao, R.

    2017-08-01

    In the present investigation, response surface methodology (RSM) is used for a quadratic model that continuously controls the process parameters. This model is used to optimize the removal of iron oxide from Partially Laterised Khondalite (PLK) rocks which is influenced by several independent variables namely acid concentration, time and temperature. Second order response functions are produced for leaching of iron oxide from PLK rocks-a bauxite mining waste. In RSM, Box-Behnken design is used for the process optimization to achieve maximum removal of iron oxide. The influence of the process variables of leaching of iron oxide is presented in the form of 3-D response graphs. The results of this investigation reveals that 3 M hydrochloric acid concentration, 240 min time and 373 K temperature are found to be the best conditions for removal of 99% Fe2O3. The product obtain at this condition contain 80% brightness which is suitable for ceramic and filler industry applications. The novelity of the work is that the waste can be a value added product after suitable physical beneficiation and chemical treatment.

  7. Reactions and reaction intermediates on iron surfaces--1. Methanol, ethanol, and isopropanol on Fe(100). 2. Hydrocarbons and carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Benziger, J.B.; Madix, R.J.

    1980-09-01

    Temperature-programed desorption and ESCA showed that the alcohols formed alkoxy intermediates on Fe(100) surfaces at room temperature, but that the methoxy and ethoxy species were much more stable than the isopropoxy intermediate. The alkoxy species reacted above 400/sup 0/K by decomposing into carbon monoxide and hydrogen, hydrogenation to alcohol, and scission of C-C and C-O bonds with hydrogenation of the hydrocarbon fragments. Ethylene, acetylene, and cis-2-butene formed stable, unidentified surface species. Methyl chloride formed stable surface methyl groups which decomposed into hydrogen and surface carbide at 475/sup 0/K. Formic and acetic acids yielded stable carboxylate intermediates which decomposed above 490/sup 0/K to hydrogen, carbon monoxide, and carbon dioxide. The studies suggested that the alkoxy surface species may be important intermediates in the Fischer-Tropsch reaction on iron.

  8. DETERMINING REFLECTANCE SPECTRA OF SURFACES AND CLOUDS ON EXOPLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Cowan, Nicolas B.; Strait, Talia E., E-mail: n-cowan@northwestern.edu [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, 2131 Tech Dr., IL 60208 (United States)

    2013-03-01

    Planned missions will spatially resolve temperate terrestrial planets from their host star. Although reflected light from such a planet encodes information about its surface, it has not been shown how to establish surface characteristics of a planet without assuming known surfaces to begin with. We present a reanalysis of disk-integrated, time-resolved, multiband photometry of Earth obtained by the Deep Impact spacecraft as part of the EPOXI Mission of Opportunity. We extract reflectance spectra of clouds, ocean, and land without a priori knowledge of the numbers or colors of these surfaces. We show that the inverse problem of extracting surface spectra from such data is a novel and extreme instance of spectral unmixing, a well-studied problem in remote sensing. Principal component analysis is used to determine an appropriate number of model surfaces with which to interpret the data. Shrink-wrapping a simplex to the color excursions of the planet yields a conservative estimate of the planet's endmember spectra. The resulting surface maps are unphysical, however, requiring negative or larger-than-unity surface coverage at certain locations. Our ''rotational unmixing'' supersedes the endmember analysis by simultaneously solving for the surface spectra and their geographical distributions on the planet, under the assumption of diffuse reflection and known viewing geometry. We use a Markov Chain Monte Carlo to determine best-fit parameters and their uncertainties. The resulting albedo spectra are similar to clouds, ocean, and land seen through a Rayleigh-scattering atmosphere. This study suggests that future direct-imaging efforts could identify and map unknown surfaces and clouds on exoplanets.

  9. Determining Surface Infiltration Rate of Permeable Pavements with Digital Imaging

    Directory of Open Access Journals (Sweden)

    Caterina Valeo

    2018-01-01

    Full Text Available Cell phone images of pervious pavement surfaces were used to explore relationships between surface infiltration rates (SIR measured using the ASTM C1701 standard test and using a simple falling head test. A fiber-reinforced porous asphalt surface and a highly permeable material comprised of stone, rubber and a polymer binder (Porous Pave were tested. Images taken with a high-resolution cellphone camera were acquired as JPEG files and converted to gray scale images in Matlab® for analysis. The distribution of gray levels was compared to the surface infiltration rates obtained for both pavements with attention given to the mean of the distribution. Investigation into the relationships between mean SIR and parameters determined from the gray level distribution produced in the image analysis revealed that mean SIR measured in both pavements were proportional to the inverse of the mean of the distribution. The relationships produced a coefficient of determination over 85% using both the ASTM and the falling head test in the porous asphalt surface. SIR measurements determined with the ASTM method were highly correlated with the inverse mean of the distribution of gray levels in the Porous Pave material as well, producing coefficients of determination of over 90% and Kendall’s tau-b of roughly 70% for nonparametric data.

  10. Development of a primary method for the determination of iron in serum

    International Nuclear Information System (INIS)

    Palos, Marie; Del Castillo Busto, Maria Estela; Fisicaro, Paola; Vaslin-Reimann, Sophie; Hattchouel, Jean-Marc; Pannier, Florence

    2015-01-01

    This work presents the development of a reference method by ICP-MS for the determination of iron in serum. To ensure the metrological traceability of the results, isotope dilution associated with ICP-MS (ID-ICP-MS) has been applied, which has the potential to be a primary measurement procedure. Method validation has been demonstrated through the use of a certified reference material (SRM 1598a) and the participation in an international comparison between National Metrology Institutes (BIPM-CCQM K107). The validated method is now available to support clinical laboratories in the evaluation of their measurement capabilities and for quality assurance and quality control programs. In fact, this ID-ICP-MS method can be used to certify reference materials or to assign reference values to samples used in proficiency testing schemes. The feasibility has been tested on two unknown samples, i.e. BCR"R -637, IRMM sample and an ANSM B17 sample (a material distributed during a National Quality Control program). (authors)

  11. Determinants of vitamin A and iron status in pregnant mothers and preschool children

    International Nuclear Information System (INIS)

    Sudhakaran, P.R.; Rajasekharan, K.N.; Menon, V.P.; Nair, K.M.; Chandrasekhar, U.; Nair, P.

    1997-01-01

    Micronutrient deficiencies, particularly deficiency of vitamin A and iron, have been recognized as a major public health problem in developing countries. This is particularly true for mothers, infants and preschool children, since these deficiencies may promote susceptibility to infectious agents and also increase the risk of developing chronic diseases in adult life. Increasing the availability of dietary provitamin A carotenoids from natural sources will improve vitamin A status among deficient populations. In order to evaluate such intervention programmes, it is essential to have biochemical and field assessment techniques. This proposal aims at conducting a demonstration project in Kerala, India using deuterated β-carotene as an intrinsic label to determine the utilization of this nutrient as a source of vitamin A. The programme design consists of i) method development phase during which Spirulina fusiformis will be grown in microreactors in presence of deuterated water for the production of labelled β-carotene and ii) an application phase wherein experimental animals (primates) will be administered labelled Spirulina to study the factors that influence the utilization of β-carotene for the formation of vitamin A. (author)

  12. Spectroscopic determination of optimal hydration time of zircon surface

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Garcia R, G. [Instituto Tecnologico de Toluca, Division de Estudios del Posgrado, Av. Tecnologico s/n, Ex-Rancho La Virgen, 52140 Metepec, Estado de Mexico (Mexico); Garcia G, N., E-mail: eduardo.ordonez@inin.gob.m [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Av. Colon y Av. Tollocan, 50180 Toluca, Estado de Mexico (Mexico)

    2010-07-01

    When a mineral surface is immersed in an aqueous solution, it develops and electric charge produced by the amphoteric dissociation of hydroxyl groups created by the hydration of the solid surface. This is one influential surface property. The complete hydration process takes a time which is specific for each mineral species. The knowledge of the aqueous solution contact time for complete surface hydration is mandatory for further surface phenomena studies. This study deals with the optimal hydration time of the raw zircon (ZrSiO{sub 4}) surface comparing the classical potentiometric titrations with a fluorescence spectroscopy technique. The latter is easy and rea liable as it demands only one sample batch to determine the optimal time to ensure a total hydration of the zircon surface. The analytical results of neutron activation analysis showed the presence of trace quantities of Dy{sup 3+}, Eu{sup 3+} and Er{sup 3} in the bulk of zircon. The Dy{sup 3+} is structured in the zircon crystalline lattice and undergoes the same chemical reactions as zircon. Furthermore, the Dy{sup 3+} has a good fluorescent response whose intensity is enhanced by hydration molecules. The results show that, according to the potentiometric analysis, the hydration process for each batch (at least 8 sample batches) takes around 2 h, while the spectrometric method indicates only 5 minutes from only one batch. Both methods showed that the zircon surface have a 16 h optimal hydration time. (Author)

  13. Spectroscopic determination of optimal hydration time of zircon surface

    International Nuclear Information System (INIS)

    Ordonez R, E.; Garcia R, G.; Garcia G, N.

    2010-01-01

    When a mineral surface is immersed in an aqueous solution, it develops and electric charge produced by the amphoteric dissociation of hydroxyl groups created by the hydration of the solid surface. This is one influential surface property. The complete hydration process takes a time which is specific for each mineral species. The knowledge of the aqueous solution contact time for complete surface hydration is mandatory for further surface phenomena studies. This study deals with the optimal hydration time of the raw zircon (ZrSiO 4 ) surface comparing the classical potentiometric titrations with a fluorescence spectroscopy technique. The latter is easy and rea liable as it demands only one sample batch to determine the optimal time to ensure a total hydration of the zircon surface. The analytical results of neutron activation analysis showed the presence of trace quantities of Dy 3+ , Eu 3+ and Er 3 in the bulk of zircon. The Dy 3+ is structured in the zircon crystalline lattice and undergoes the same chemical reactions as zircon. Furthermore, the Dy 3+ has a good fluorescent response whose intensity is enhanced by hydration molecules. The results show that, according to the potentiometric analysis, the hydration process for each batch (at least 8 sample batches) takes around 2 h, while the spectrometric method indicates only 5 minutes from only one batch. Both methods showed that the zircon surface have a 16 h optimal hydration time. (Author)

  14. Examinations for the determination of the flux density of sputtered iron using laser induced fluorescence

    International Nuclear Information System (INIS)

    Schweer, H.B.

    1983-11-01

    In this work investigations are described to measure the flux density of sputtered iron atoms by means of laser induced fluorescence. In a laboratory experiment an iron target (stainless steel 316, Inconel 600), was bombarded with 10 keV Ar + and 2.5 keV H + and the population distribution of the energy levels of the ground state a 5 D and the metastable state a 5 F was measured. In the plasma wall region in the ISX-B tokamak at the Oak Ridge National Laboratory (USA) neutral iron atoms were measured the first time by laser induced fluorescence. A detection limit of 10 6 atoms/cm 3 was found and sputtered iron atoms were observed in the first 15 ms of the discharge. (orig./BRB)

  15. Surface temperature and surface heat flux determination of the inverse heat conduction problem for a slab

    International Nuclear Information System (INIS)

    Kuroyanagi, Toshiyuki

    1983-07-01

    Based on an idea that surface conditions should be a reflection of interior temperature and interior heat flux variation as inverse as interior conditions has been determined completely by the surface temperature and/on surface heat flux as boundary conditions, a method is presented for determining the surface temperature and the surface heat flux of a solid when the temperature and heat flux at an interior point are a prescribed function of time. The method is developed by the integration of Duhumels' integral which has unknown temperature or unknown heat flux in its integrand. Specific forms of surface condition determination are developed for a sample inverse problem: slab. Ducussing the effect of a degree of avairable informations at an interior point due to damped system and the effect of variation of surface conditions on those formulations, it is shown that those formulations are capable of representing the unknown surface conditions except for small time interval followed by discontinuous change of surface conditions. The small un-resolved time interval is demonstrated by a numerical example. An evaluation method of heat flux at an interior point, which is requested by those formulations, is discussed. (author)

  16. Preparation of iron-deposited graphite surface for application as cathode material during electrochemical vat-dyeing process

    International Nuclear Information System (INIS)

    Anbu Kulandainathan, M.; Kiruthika, K.; Christopher, G.; Babu, K. Firoz; Muthukumaran, A.; Noel, M.

    2008-01-01

    Iron-deposited graphite surfaces were prepared, characterized and employed as cathode materials for electrochemical vat-dyeing process containing very low concentration of sodium dithionite. The electrodeposition, in presence of ammonium thiocyanate and gelatin or animal glue as binding additives, were found to give finer iron deposits for improved electrochemical dyeing application. The electrodeposits were characterized using scanning electron microscopy, electron-dispersive X-ray spectroscopy and X-ray diffraction methods, before and after electrochemical dyeing process. The electrochemical activity of the iron-deposited graphite electrodes always stored in water seems to depend on the surface-bound Fe 3+ /Fe 2+ redox species. Vat dyes like C.I. Vat Violet 1, C.I. Vat Green 1 and C.I. Vat Blue 4 could be efficiently dyed employing these above electrode materials. The colour intensity and washing fastness of the dyed fabrics were found to be equal with conventionally dyed fabrics. The electrodes could also be reused for the dyeing process

  17. Molecular analysis of long-term biofilm formation on PVC and cast iron surfaces in drinking water distribution system.

    Science.gov (United States)

    Liu, Ruyin; Zhu, Junge; Yu, Zhisheng; Joshi, DevRaj; Zhang, Hongxun; Lin, Wenfang; Yang, Min

    2014-04-01

    To understand the impacts of different plumbing materials on long-term biofilm formation in water supply system, we analyzed microbial community compositions in the bulk water and biofilms on faucets with two different materials-polyvinyl chloride (PVC) and cast iron, which have been frequently used for more than10 years. Pyrosequencing was employed to describe both bacterial and eukaryotic microbial compositions. Bacterial communities in the bulk water and biofilm samples were significantly different from each other. Specific bacterial populations colonized on the surface of different materials. Hyphomicrobia and corrosion associated bacteria, such as Acidithiobacillus spp., Aquabacterium spp., Limnobacter thiooxidans, and Thiocapsa spp., were the most dominant bacteria identified in the PVC and cast iron biofilms, respectively, suggesting that bacterial colonization on the material surfaces was selective. Mycobacteria and Legionella spp. were common potential pathogenic bacteria occurred in the biofilm samples, but their abundance was different in the two biofilm bacterial communities. In contrast, the biofilm samples showed more similar eukaryotic communities than the bulk water. Notably, potential pathogenic fungi, i.e., Aspergillus spp. and Candida parapsilosis, occurred in similar abundance in both biofilms. These results indicated that microbial community, especially bacterial composition was remarkably affected by the different pipe materials (PVC and cast iron). Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  18. Differential proteomics analysis of the surface heterogeneity of dextran iron oxide nanoparticles and the implications for their in vivo clearance.

    Science.gov (United States)

    Simberg, Dmitri; Park, Ji-Ho; Karmali, Priya P; Zhang, Wan-Ming; Merkulov, Sergei; McCrae, Keith; Bhatia, Sangeeta N; Sailor, Michael; Ruoslahti, Erkki

    2009-08-01

    In order to understand the role of plasma proteins in the rapid liver clearance of dextran-coated superparamagnetic iron oxide (SPIO) in vivo, we analyzed the full repertoire of SPIO-binding blood proteins using novel two-dimensional differential mass spectrometry approach. The identified proteins showed specificity for surface domains of the nanoparticles: mannan-binding lectins bound to the dextran coating, histidine-rich glycoprotein and kininogen bound to the iron oxide part, and the complement lectin and contact clotting factors were secondary binders. Nanoparticle clearance studies in knockout mice suggested that these proteins, as well as several previously identified opsonins, do not play a significant role in the SPIO clearance. However, both the dextran coat and the iron oxide core remained accessible to specific probes after incubation of SPIO in plasma, suggesting that the nanoparticle surface could be available for recognition by macrophages, regardless of protein coating. These data provide guidance to rational design of bioinert, long-circulating nanoparticles.

  19. Evaluation of MR imaging with T1 and T2* mapping for the determination of hepatic iron overload.

    Science.gov (United States)

    Henninger, B; Kremser, C; Rauch, S; Eder, R; Zoller, H; Finkenstedt, A; Michaely, H J; Schocke, M

    2012-11-01

    To evaluate MRI using T1 and T2* mapping sequences in patients with suspected hepatic iron overload (HIO). Twenty-five consecutive patients with clinically suspected HIO were retrospectively studied. All underwent MRI and liver biopsy. For the quantification of liver T2* values we used a fat-saturated multi-echo gradient echo sequence with 12 echoes (TR = 200 ms, TE = 0.99 ms +  n × 1.41 ms, flip angle 20°). T1 values were obtained using a fast T1 mapping sequence based on an inversion recovery snapshot FLASH sequence. Parameter maps were analysed using regions of interest. ROC analysis calculated cut-off points at 10.07 ms and 15.47 ms for T2* in the determination of HIO with accuracy 88 %/88 %, sensitivity 84 %/89.5 % and specificity 100 %/83 %. MRI correctly classified 20 patients (80 %). All patients with HIO only had decreased T1 and T2* relaxation times. There was a significant difference in T1 between patients with HIO only and patients with HIO and steatohepatitis (P = 0.018). MRI-based T2* relaxation diagnoses HIO very accurately, even at low iron concentrations. Important additional information may be obtained by the combination of T1 and T2* mapping. It is a rapid, non-invasive, accurate and reproducible technique for validating the evidence of even low hepatic iron concentrations. • Hepatic iron overload causes fibrosis, cirrhosis and increases hepatocellular carcinoma risk. • MRI detects iron because of the field heterogeneity generated by haemosiderin. • T2* relaxation is very accurate in diagnosing hepatic iron overload. • Additional information may be obtained by T1 and T2* mapping.

  20. Room-temperature susceptometry predicts biopsy-determined hepatic iron in patients with elevated serum ferritin.

    Science.gov (United States)

    Maliken, Bryan D; Avrin, William F; Nelson, James E; Mooney, Jody; Kumar, Sankaran; Kowdley, Kris V

    2012-01-01

    There is an ongoing clinical need for novel methods to measure hepatic iron content (HIC) noninvasively. Both magnetic resonance imaging (MRI) and superconducting quantum interference device (SQUID) methods have previously shown promise for estimation of HIC, but these methods can be expensive and are not widely available. Room-temperature susceptometry (RTS) represents an inexpensive alternative and was previously found to be strongly correlated with HIC estimated by SQUID measurements among patients with transfusional iron overload related to thalassemia. The goal of the current study was to examine the relationship between RTS and biochemical HIC measured in liver biopsy specimens in a more varied patient cohort. Susceptometry was performed in a diverse group of patients with hyperferritinemia due to hereditary hemochromatosis (HHC) (n = 2), secondary iron overload (n = 3), nonalcoholic fatty liver disease (NAFLD) (n = 2), and chronic viral hepatitis (n = 3) within one month of liver biopsy in the absence of iron depletion therapy. The correlation coefficient between HIC estimated by susceptometry and by biochemical iron measurement in liver tissue was 0.71 (p = 0.022). Variance between liver iron measurement and susceptometry measurement was primarily related to reliance on the patient's body-mass index (BMI) to estimate the magnetic susceptibility of tissue overlying the liver. We believe RTS holds promise for noninvasive measurement of HIC. Improved measurement techniques, including more accurate overlayer correction, may further improve the accuracy of liver susceptometry in patients with liver disease.

  1. Diffusion Coefficient in the Zinc Coating Shaped on the Surface of Cast Iron and Steel Alloys

    Directory of Open Access Journals (Sweden)

    Kopyciński D.

    2015-06-01

    Full Text Available The article presents the method to assess the diffusion coefficient D in the sub-layer of intermetallic phases formed during hot-dip galvanizing “Armco” iron and ductile cast iron EN-GJS-500-7. Hot-dip galvanizing is one of the most popular forms of long-term protection of Fe-C alloys against corrosion. The process for producing a protective layer of sufficient quality is closely related to diffusion of atoms of zinc and iron. The simulation consist in performed a hot-dip galvanizing in laboratory condition above Fe-C alloys, in the Department of Engineering of Cast Alloys and Composites. Galvanizing time ranged from 15 to 300 seconds. Then metallographic specimens were prepared, intermetallic layers were measured and diffusion coefficient (D were calculated. It was found that the diffusion coefficient obtained during hot-dip galvanizing “Armco” iron and zinc is about two orders of magnitude less than the coefficient obtained on ductile cast iron EN-GJS-500-7.

  2. Quantative determination of surface temperatures using an infrared camera

    International Nuclear Information System (INIS)

    Hsieh, C.K.; Ellingson, W.A.

    1977-01-01

    A method is presented to determine the surface-temperature distribution at each point in an infrared picture. To handle the surface reflection problem, three cases are considered that include the use of black coatings, radiation shields, and band-pass filters. For uniform irradiation on the test surface, the irradiation can be measured by using a cooled, convex mirror. Equations are derived to show that this surrounding irradiation effect can be subtracted out from the scanned radiation; thus the net radiation is related to only emission from the surface. To provide for temperature measurements over a large field, the image-processing technique is used to digitize the infrared data. The paper spells out procedures that involve the use of a computer for making point-by-point temperature calculations. Finally, a sample case is given to illustrate applications of the method. 6 figures, 1 table

  3. Applications of surface analysis in the environmental sciences: dehalogenation of chlorocarbons with zero-valent iron and iron-containing mineral surfaces

    Energy Technology Data Exchange (ETDEWEB)

    McGuire, Molly M.; Carlson, Daniel L.; Vikesland, Peter J.; Kohn, Tamar; Grenier, Adam C.; Langley, Laura A.; Roberts, A. Lynn; Fairbrother, D. Howard

    2003-10-31

    Halogenated organic compounds are common pollutants in groundwater. Consequently, there is widespread interest in understanding the reactions of these compounds in the environment and developing remediation strategies. One area of ongoing research involves the reductive dechlorination of organohalides with zero-valent metals or metal sulfide minerals. These processes have been studied almost exclusively from the perspective of the aqueous phase. In this paper we illustrate the utility of surface analysis techniques, including electron spectroscopies, vibrational spectroscopies, and atomic force microscopy in elucidating the roles played by the surface. A dual analysis approach to the study of reductive dechlorination, combining traditional solution phase analysis with surface analytical techniques, also is demonstrated using a liquid cell coupled to an ultrahigh vacuum surface analysis chamber.

  4. Superparamagnetic iron oxide coated on the surface of cellulose nanospheres for the rapid removal of textile dye under mild condition

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Yunfeng [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, and College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Qin, Zongyi, E-mail: phqin@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, and College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Liu, Yannan; Cheng, Miao; Qian, Pengfei [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, and College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Wang, Qian, E-mail: drwangqian23@163.com [Department of Orthopaedics, Shanghai First People' s Hospital, Shanghai Jiaotong University, 100 Haining Road, Hongkou District, Shanghai 200080 (China); Zhu, Meifang [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, and College of Material Science and Engineering, Donghua University, Shanghai 201620 (China)

    2015-12-01

    Graphical abstract: - Highlights: • Anchoring superparamagnetic iron oxide on the surface of cellulose nanospheres as magnetically recyclable nanocatalys. • Achieving highly efficient Fenton-like reaction on the surface of composite nanospheres for rapid removal of textile dye. • Reaching nearly 98.0% degradation of Navy blue within 5 min under mild condition. - Abstract: Magnetic composite nanoparticles (MNPs) were prepared by anchoring iron oxide (Fe{sub 3}O{sub 4}) on the surface of carboxyl cellulose nanospheres through a facile chemical co-precipitation method. The as-prepared MNPs were characterized by atomic force microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, wide-angle X-ray diffraction measurement, thermal gravity analysis and vibrating sample magnetometry. These MNPs were of a generally spherical shape with a narrow size distribution, and exhibited superparamagnetic behaviors with high saturation magnetization. High efficient removal of Navy blue in aqueous solution was demonstrated at room temperature in a Fenton-like system containing the MNPs and H{sub 2}O{sub 2}, which benefited from small particle size, large surface area, high chemical activity, and good dispersibility of the MNPs. The removal efficiency of Navy blue induced by the MNPs prepared at a weight ratio of cellulose to iron of 1:2 were 90.6% at the first minute of the degradation reaction, and 98.0% for 5 min. Furthermore, these MNPs could be efficiently recycled and reused by using an external magnetic field. The approach presented in this paper promotes the use of renewable natural resources as templates for the preparation and stabilization of various inorganic nanomaterials for the purpose of catalysis, magnetic resonance imaging, biomedical and other potential applications.

  5. Cast irons

    CERN Document Server

    1996-01-01

    Cast iron offers the design engineer a low-cost, high-strength material that can be easily melted and poured into a wide variety of useful, and sometimes complex, shapes. This latest handbook from ASM covers the entire spectrum of one of the most widely used and versatile of all engineered materials. The reader will find the basic, but vital, information on metallurgy, solidification characteristics, and properties. Extensive reviews are presented on the low-alloy gray, ductile, compacted graphite, and malleable irons. New and expanded material has been added covering high-alloy white irons used for abrasion resistance and high-alloy graphitic irons for heat and corrosion resistance. Also discussed are melting furnaces and foundry practices such as melting, inoculation, alloying, pouring, gating and rising, and molding. Heat treating practices including stress relieving, annealing, normalizing, hardening and tempering, autempering (of ductile irons), and surface-hardening treatments are covered, too. ASM Spec...

  6. Influence of iron solubility and charged surface-active compounds on lipid oxidation in fatty acid ethyl esters containing association colloids.

    Science.gov (United States)

    Homma, Rika; Johnson, David R; McClements, D Julian; Decker, Eric A

    2016-05-15

    The impact of iron compounds with different solubilities on lipid oxidation was studied in the presence and absence of association colloids. Iron (III) sulfate only accelerated lipid oxidation in the presence of association colloids while iron (III) oleate accelerated oxidation in the presence and absence of association colloids. Further, iron (III) oxide retarded lipid oxidation both with and without association colloids. The impact of charged association colloids on lipid oxidation in ethyl oleate was also investigated. Association colloids consisting of the anionic surface-active compound dodecyl sulphosuccinate sodium salt (AOT), cationic surface-active compound hexadecyltrimethylammonium bromide (CTAB), and nonionic surface-active compound 4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton X-100) retarded, promoted, and had no effect on lipid oxidation rates, respectively. These results indicate that the polarity of metal compounds and the charge of association colloids play a big role in lipid oxidation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Environmental application of millimeter-scale sponge iron (s-Fe{sup 0}) particles (II): The effect of surface copper

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Yongming, E-mail: juyongming@scies.org [South China Institute of Environmental Sciences, The Ministry of Environmental Protection of the PRC, Guangzhou 510655 (China); Liu, Xiaowen, E-mail: liuxiaowen@scies.org [South China Institute of Environmental Sciences, The Ministry of Environmental Protection of the PRC, Guangzhou 510655 (China); Liu, Runlong; Li, Guohua; Wang, Xiaoyan; Yang, Yanyan; Wei, Dongyang; Fang, Jiande [South China Institute of Environmental Sciences, The Ministry of Environmental Protection of the PRC, Guangzhou 510655 (China); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering (DBCEE), University of Cincinnati, Cincinnati, Ohio 45221-0012 (United States)

    2015-04-28

    Highlights: • Facile reduction reaction achieves decoration of Cu{sup 0} onto the surface of s-Fe{sup 0}. • The removal efficiency of RhB over Cu{sup 0}–s-Fe{sup 0} was similar to that of Cu{sup 0}–nZVI. • Cu{sup 0}–s-Fe{sup 0} can operate under mild condition with lower cost compared to nZVI. • The reductive mechanism over Cu{sup 0}–s-Fe{sup 0} under US condition is also elucidated. - Abstract: To enhance the catalytic reactivity of millimeter-scale particles of sponge iron (s-Fe{sup 0}), Cu{sup 2+} ions were deposited on the surface of s-Fe{sup 0} using a simple direct reduction reaction, and the catalytic properties of the bimetallic system was tested for removal of rhodamine B (RhB) from an aqueous solution. The influence of Cu{sup 0} loading, catalyst dosage, particle size, initial RhB concentration, and initial pH were investigated, and the recyclability of the catalyst was also assessed. The results demonstrate that the 3 ∼ 5 millimeter s-Fe{sup 0} particles (s-Fe{sup 0}(3 ∼ 5 mm)) with 5 wt% Cu loading gave the best results. The removal of RhB followed two-step, pseudo-first-order reaction kinetics. Cu{sup 0}–s-Fe{sup 0} showed excellent stability after five reuse cycles. Cu{sup 0}–s-Fe{sup 0} possesses great advantages compared to nanoscale zero-valent iron, iron power, and iron flakes as well as its bimetals. The surface Cu{sup 0} apparently catalyzes the production of reactive hydrogen atoms for indirect reaction and generates Fe-Cu galvanic cells that enhance electron transfer for direct reaction. This bimetallic catalyst shows great potential for the pre-treatment of recalcitrant wastewaters. Additionally, some oxides containing iron element are selected to simulate the adsorption process. The results prove that the adsorption process of FeOOH, Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4} played minor role for the removal of RhB.

  8. A comparison of in vivo and in vitro methods for determining availability of iron from meals

    International Nuclear Information System (INIS)

    Schricker, B.R.; Miller, D.D.; Rasmussen, R.R.; Van Campen, D.

    1981-01-01

    A comparison is made between in vitro and human and rat in vivo methods for estimating food iron availability. Complex meals formulated to replicate meals used by Cook and Monsen (Am J Clin Nutr 1976;29:859) in human iron availability trials were used in the comparison. The meals were prepared by substituting pork, fish, cheese, egg, liver, or chicken for beef in two basic test meals and were evaluated for iron availability using in vitro and rat in vivo methods. When the criterion for comparison was the ability to show statistically significant differences between iron availability in the various meals, there was substantial agreement between the in vitro and human in vivo methods. There was less agreement between the human in vivo and the rat in vivo and between the in vivo and the rat in vivo and between the in vitro and the rat in vivo methods. Correlation analysis indicated significant agreement between in vitro and human in vivo methods. Correlation between the rat in vivo and human in vivo methods were also significant but correlations between the in vitro and rat in vivo methods were less significant and, in some cases, not significant. The comparison supports the contention that the in vitro method allows a rapid, inexpensive, and accurate estimation of nonheme iron availability in complex meals

  9. Liver iron content determined by MRI. Spin-echo vs. gradient-echo

    Energy Technology Data Exchange (ETDEWEB)

    Juchems, M.S.; Wunderlich, A.P. [Universitaetskliniken Ulm (Germany). Klinik fuer Diagnostische und Interventionelle Radiologie; Cario, H. [Universitaetskliniken Ulm (Germany). Klinik fuer Kinder- und Jugendmedizin; Schmid, M. [Stadtspital Triemli, Zuerich (Switzerland). Medizinische Onkologie und Haematologie

    2012-05-15

    Purpose: Liver iron content (LIC) measurement plays a central role in the management of patients with transfusional iron overload. Calculating the LIC with data obtained from standardized MRI sequences represents an attractive alternative diagnostic possibility. The purpose of this study was to compare the LIC measurement obtained with gradient-echo (GRE) sequences to the mean liver proton transverse relaxation (R2) acquired with SE sequences. Materials and Methods: 68 patients with iron overload (median age: 24, range: 3 - 88) underwent 1.5 T MRI for liver iron content measurement. All patients received spin-echo (SE) and gradient-echo (GRE) sequences. Results: The two MRI methods revealed different liver iron content results although a significant correlation was found (r = 0.85, p < 0.001). Values evaluated using GRE sequences (median: 260 {mu}mol/g dry weight [d.w.], range: 6 - 732) were generally higher than those obtained by SE examinations (median: 161 {mu}mol /g d.w., range: 5 - 830). Conclusion: In conclusion, our study revealed different results for both MRI measurements, which could lead to different decisions concerning the management of chelation therapy in individual patients. (orig.)

  10. Chitosan-iron oxide nanocomposite based electrochemical aptasensor for determination of malathion

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakar, Nirmal, E-mail: nirmalprabhakar@gmail.com; Thakur, Himkusha; Bharti, Anu; Kaur, Navpreet

    2016-10-05

    An electrochemical aptasensor based on chitosan-iron oxide nanocomposite (CHIT-IO) film deposited on fluorine tin Oxide (FTO) was developed for the detection of malathion. Iron oxide nanoparticles were prepared by co-precipitation method and characterized by Transmission electron microscopy and UV–Visible spectroscopy. The biotinylated DNA aptamer sequence specific to the malathion was immobilized onto the iron oxide doped-chitosan/FTO electrode by using streptavidin as linking molecule. Various characterization studies like Field Emission-Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and Electrochemical studies were performed to attest the successful fabrication of bioelectrodes. Experimental parameters like aptamer concentration, response time, stability of electrode and reusability studies were optimized. Aptamer immobilized chitosan-iron oxide nanocomposite (APT/SA/CHIT-IO/FTO) bioelectrodes exhibited LOD of about 0.001 ng/mL within 15 min and spike-in studies revealed about 80–92% recovery of malathion from the lettuce leaves and soil sample. - Highlights: • An electrochemical aptasensor for the detection of Malathion has been developed. • Chitosan-iron oxide NP deposited FTO sheets provides platform for aptamer immobilization. • Aptasensor has efficiency to detect malathion upto 0.001 ng/mL within 15 min.

  11. Halloysite Nanotubes as a New Adsorbent for Solid Phase Extraction and Spectrophotometric Determination of Iron in Water and Food Samples

    Science.gov (United States)

    Samadi, A.; Amjadi, M.

    2016-07-01

    Halloysite nanotubes (HNTs) have been introduced as a new solid phase extraction adsorbent for preconcentration of iron(II) as a complex with 2,2-bipyridine. The cationic complex is effectively adsorbed on the sorbent in the pH range of 3.5-6.0 and efficiently desorbed by trichloroacetic acid. The eluted complex has a strong absorption around 520 nm, which was used for determination of Fe(II). After optimizing extraction conditions, the linear range of the calibration graph was 5.0-500 μg/L with a detection limit of 1.3 μg/L. The proposed method was successfully applied for the determination of trace iron in various water and food samples, and the accuracy was assessed through the recovery experiments and analysis of a certified reference material (NIST 1643e).

  12. High performance liquid chromatographic determination of vanadium in crude oils and cobalt and iron in pharmaceutical preparations

    International Nuclear Information System (INIS)

    Khuhawar, M.Y.; Lanjwani, S.N.; Khaskhely, G.Q.

    1993-01-01

    High performance liquid Chromatographic (HPLC) method has ben developed for the determination of vanadium in crude oils, based on acid decomposition of oils, followed by complexation with bis (salicylaldehyde) tetramethyl ethylenediamine (H2SA2Ten). The complex is extracted in organic phase and is separated from copper and nickel using normal phase HPLC column. Detection is achieved using spectrophtmetric detector. The vanadium in oil is obtained at sub microgram/g level. Similarly cobalt(II), cobalt(III) and iron(II) are separated on reversed phase HPLC column. Pre column derivatization is used to develop HPLC method for the determination of cobalt and iron in pharmaceutical preparations. Finally results are compared using atomic absorption spectrometer. (author)

  13. Revealing the surface pattern of medieval pattern welded iron objects - etching tests conducted on reconstructed composites

    Czech Academy of Sciences Publication Activity Database

    Thiele, Á.; Hošek, Jiří; Haramza, M.; Török, B.

    2014-01-01

    Roč. 25, č. 1 (2014), s. 18-24 ISSN 1805-7241 R&D Projects: GA ČR GAP405/12/2289 Institutional support: RVO:67985912 Keywords : etching * pattern welding * phosphoric iron * archaeometallurgy Subject RIV: AC - Archeology, Anthropology, Ethnology

  14. In vitro degradation and surface bioactivity of iron-matrix composites containing silicate-based bioceramic

    NARCIS (Netherlands)

    Wang, S; Xu, Y; Zhou, J.; Li, H; Chang, Jiang; Huan, Z

    2017-01-01

    Iron-matrix composites with calcium silicate (CS) bioceramic as the reinforcing phase were fabricated through powder metallurgy processes. The microstructures, mechanical properties, apatite deposition and biodegradation behavior of the Fe-CS composites, as well as cell attachment and proliferation

  15. Determination of trace impurities in iron-based alloy using neutron activation analysis

    International Nuclear Information System (INIS)

    Zaidi, J.H.; Waheed, S.; Ahmad, S.

    2000-01-01

    A radiochemical neutron activation analysis procedure has been developed and applied to investigate 40 major, minor, and trace impurities in iron-based alloy. A comparison of RNAA and INAA indicated a significant improvement in the detection limits. The extensive use of these alloys in the heavy mechanical industry, manufacturing of aircraft engines, nuclear applications, medical devices and chemical equipment requires their precise characterization. The concentration of iron in the iron-based alloy was found to be 86.7%, whereas Ca, Cr, K, Mg, Mn, V and W were the other constituents of the alloy, which constituted to around 12.89%. The rest of the elements were present in minor or trace levels. Most of the rare earth elements were also present in trace amounts. (orig.)

  16. Electron Emission by N6+ Ions Scattered at a Magnetized Iron Surface

    International Nuclear Information System (INIS)

    Solleder, B.; Lemell, C.; Burgdoerfer, J.; Tokesi, K.

    2006-01-01

    Complete text of publication follows. Magnetized materials are of considerable interest in the electronics industry (hard discs, spintronics, etc.). A detailed understanding of the properties of magnetized surfaces is therefore important to optimize technical applications. In the last decades, different experimental techniques have been developed to probe spin effects in magnetized materials. In this work the spin polarization of electrons emitted during the impact of N 6+ ions on a magnetized Fe surface is investigated. We study potential emission (PE) of electrons as well as secondary electron (SE) production and transport in the target with the help of Monte Carlo (MC) simulations. Spin dependence of electron transfer processes and of transport in the solid are included. Fig. 1 shows the results of our simulation for the energy distribution and spin polarization of emitted electrons in comparison with experimental data of Pfandzelter et al. [1] for the interaction of N 6+ ions with magnetized Fe. Electrons with energies higher than 200 eV are predominantly PE electrons, emitted close to the surface via autoionization (AI), Auger capture (AC) and Auger deexcitation (AD) channels. Low energy electrons are dominated by promoted, autoionized, and secondary electrons. The polarization of above surface electrons is determined by the high of the potential barrier separating projectile and target. At large distances, the barrier drops only slightly below the Fermi edge and enables transitions of electrons from this part of the band structure which has about 50% polarization. These electrons are transferred to high n states feeding promotion and AI processes between high lying states. Electrons emitted by these processes therefore reflect the polarization near the Fermi edge. Close to the surface, the barrier is low enough to allow for electron capture from the entire conduction band. K-Auger electrons are emitted in immediate vicinity of the surface and therefore mirror

  17. Chitosan Capped Silver Nanoparticles as Colorimetric Sensor for the Determination of Iron(III

    Directory of Open Access Journals (Sweden)

    Javad Tashkhourian

    2017-12-01

    Full Text Available A selective, simple and low-cost method for the colorimetric determination of Fe3+ ions based on chitosan capped silver nanoparticles (Chit-AgNPs was presented. Chitosan is a cationic polyelectrolyte and possesses amino and hydroxy groups which make it widely used as a capping agent for Ag NPs. The synthesized chitosan capped silver nanoparticles with excellent colloidal stability were characterized by UV–Visible spectrometry, transmission electron microscopy, Fourier transform infrared, X-ray diffraction. Chit-AgNPs exhibit a strong surface plasmon resonance band which disappears in the presence of increasing concentrations of Fe3+ ions. This system showed a visually detectable color change from brownish-yellow to colorless for the selective determination of Fe3+. The method can be applied for the determination of Fe3+ ions in the concentration range of 1.0×10-6 to 5.0×10-4 M. The detection limit was determined from three times the standard deviation of the blank signal (3σ/slope as 5.3 × 10−7 M. The developed method was successfully applied for the determination of Fe3+in real samples

  18. Electronic properties and surface reactivity of SrO-terminated SrTiO3 and SrO-terminated iron-doped SrTiO3.

    Science.gov (United States)

    Staykov, Aleksandar; Tellez, Helena; Druce, John; Wu, Ji; Ishihara, Tatsumi; Kilner, John

    2018-01-01

    Surface reactivity and near-surface electronic properties of SrO-terminated SrTiO 3 and iron doped SrTiO 3 were studied with first principle methods. We have investigated the density of states (DOS) of bulk SrTiO 3 and compared it to DOS of iron-doped SrTiO 3 with different oxidation states of iron corresponding to varying oxygen vacancy content within the bulk material. The obtained bulk DOS was compared to near-surface DOS, i.e. surface states, for both SrO-terminated surface of SrTiO 3 and iron-doped SrTiO 3 . Electron density plots and electron density distribution through the entire slab models were investigated in order to understand the origin of surface electrons that can participate in oxygen reduction reaction. Furthermore, we have compared oxygen reduction reactions at elevated temperatures for SrO surfaces with and without oxygen vacancies. Our calculations demonstrate that the conduction band, which is formed mainly by the d-states of Ti, and Fe-induced states within the band gap of SrTiO 3 , are accessible only on TiO 2 terminated SrTiO 3 surface while the SrO-terminated surface introduces a tunneling barrier for the electrons populating the conductance band. First principle molecular dynamics demonstrated that at elevated temperatures the surface oxygen vacancies are essential for the oxygen reduction reaction.

  19. Determination of forest road surface roughness by Kinect depth imaging

    Directory of Open Access Journals (Sweden)

    Francesco Marinello

    2017-12-01

    Full Text Available Roughness is a dynamic property of the gravel road surface that affects safety, ride comfort as well as vehicle tyre life and maintenance costs. A rapid survey of gravel road condition is fundamental for an effective maintenance planning and definition of the intervention priorities.Different non-contact techniques such as laser scanning, ultrasonic sensors and photogrammetry have recently been proposed to reconstruct three-dimensional topography of road surface and allow extraction of roughness metrics. The application of Microsoft Kinect™ depth camera is proposed and discussed here for collection of 3D data sets from gravel roads, to be implemented in order to allow quantification of surface roughness.The objectives are to: i verify the applicability of the Kinect sensor for characterization of different forest roads, ii identify the appropriateness and potential of different roughness parameters and iii analyse the correlation with vibrations recoded by 3-axis accelerometers installed on different vehicles. The test took advantage of the implementation of the Kinect depth camera for surface roughness determination of 4 different forest gravel roads and one well-maintained asphalt road as reference. Different vehicles (mountain bike, off-road motorcycle, ATV vehicle, 4WD car and compact crossover were included in the experiment in order to verify the vibration intensity when travelling on different road surface conditions. Correlations between the extracted roughness parameters and vibration levels of the tested vehicles were then verified. Coefficients of determination of between 0.76 and 0.97 were detected between average surface roughness and standard deviation of relative accelerations, with higher values in the case of lighter vehicles.

  20. Morphology and phase structures of CW laser-induced oxide layers on iron surface with evolving reflectivity and colors

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Taotao, E-mail: wutaotao@nint.ac.cn; Wang, Lijun; Wei, Chenghua; Zhou, Menglian; He, Minbo; Wu, Lixiong

    2016-11-30

    Highlights: • Firstly, iron samples with different color features were obtained by continuous wave laser irradiation depending on progressive durations. The real-time reflectivity and temperature of samples were measured. The color and the reflectivity evolution were related. They were both caused by the forming oxide films. • Secondly, laser-induced oxidation process of iron was studied by microscope, X-ray diffraction and Raman spectrum. The first formed magnetite made the surface reflectivity decline rapidly and caused the “positive feedback” effect because of molecular absorption. The later formed hematite oscillated the reflectivity by interference effect. • Lastly, the laser-induced oxide films were thin, orientated and badly crystallized. The Wagner oxidation theory was incapable of describing the non-isothermal and early stage oxidation process. So we emphasized that a precise oxidation model depending on the experiment and the optical constants of the laser-induced oxides must be studied. - Abstract: Laser-induced oxidation will change the laser reflectivity and color features of metal surface. Both changes can be theoretically calculated based on the oxidation kinetics and the optical constants of oxides. For the purpose of calculation, the laser-induced oxidation process of pure polycrystalline iron was studied. Samples with various color features were obtained by continuous wave Nd:YAG fiber laser (1.06 μm) irradiation depending on progressive durations in the intensity of 1.90 W/cm{sup 2}. The real-time reflectivity and temperature were measured with integral sphere and thermocouples. The irradiated surface morphology and phase structures were characterized by microscope, X-ray diffraction and Raman spectrum. It was found that the first formed magnetite made the surface reflectivity decline rapidly and caused the “positive feedback” effect because of molecular absorption. The later formed hematite oscillated the reflectivity by

  1. Voltammetric determination of total dissolved iron in coastal waters using a glassy carbon electrode modified with reduced graphene oxide, Methylene Blue and gold nanoparticles

    International Nuclear Information System (INIS)

    Lin, Mingyue; Zhang, Haiyun; Han, Haitao; Pan, Dawei; Su, Zhencui

    2015-01-01

    A nanocomposite, prepared from reduced graphene oxide (rGO), Methylene Blue (MB) and gold nanoparticles (AuNPs), was used to modify a glassy carbon electrode for the determination of total dissolved iron by differential pulse voltammetry. The use of rGO warrants a larger electrode surface and the presence of more active sites, while electron transfer is accelerated by incorporating AuNPs. MB acts as an electron mediator, as an anchor for the AuNPs (which were grown in situ), and also prevents the aggregation of rGO. The modified electrode displayed a remarkably improved sensitivity and selectivity for Fe(III). The kinetics of the electrode reaction is adsorption-controlled, and the reversible process involves one proton and one electron. The response to Fe(III) is linear in the 0.3 to 100 μM concentration range, and the detection limit is 15 nM. Possible interferences by other ions were studied. The electrode was successfully applied to the determination of total dissolved iron in real coastal waters. (author)

  2. Determination of 3D Equilibria from Flux Surface Knowledge Only

    International Nuclear Information System (INIS)

    Mynick, H.E.; Pomphrey, N.

    2001-01-01

    We show that the method of Christiansen and Taylor, from which complete tokamak equilibria can be determined given only knowledge of the shape of the flux surfaces, can be extended to 3-dimensional equilibria, such as those of stellarators. As for the tokamak case, the given geometric knowledge has a high degree of redundancy, so that the full equilibrium can be obtained using only a small portion of that information

  3. Identification and determination of the contribution of iron-steel manufacturing industry to sediment-associated polycyclic aromatic hydrocarbons (PAHs) in a large shallow lake of eastern China.

    Science.gov (United States)

    Zhang, Liu; Bai, Ya-Shu; Wang, Ji-Zhong; Peng, Shu-Chuan; Chen, Tian-Hu; Yin, Da-Qiang

    2016-11-01

    Seventeen polycyclic aromatic hydrocarbon (PAH) compounds were determined in surface sediments collected from the Chaohu Lake (a large shallow lake in eastern China) and its tributaries. Both diagnostic ratios and a receptor model (positive matrix factorization, PMF) were applied to identify and determine the contribution of a local iron-steel manufacturing plant located in the Nanfei River (NFR) to the Chaohu Lake basin. The results show that sites located in the downstream of the steel plant contained concentrations of 17 PAH (Σ 17 PAH) approximately two orders of magnitudes higher than those from other sites. Five factors were identified by the PMF model, including industrial waste, wood/biomass burning, diagenetic origin, domestic coal combustion, and industrial combustion. Our findings suggest that sediments in the downstream of the plant and in the western part of the Chaohu Lake were predominantly affected by industrial coal combustion. A mixture of pyrolytic origins impacted urban sediments in the upstream of the plant, whereas diagenetic origins along with coal and biomass burning were suggested to influence the eastern part and rural tributaries of the lake. To assess the potential ecological risk and toxicity caused by the iron-steel plant, sediment toxicity was evaluated by the PMF model, sediment quality guideline, and toxic equivalent factors. All of the three approaches suggested PAH accumulation in the NFR sediments could produce significant adverse ecological effects and half of the sediment toxicity in the NFR may be attributed to the emissions from the iron-steel plant. Some rural locations also exhibited PAH concentrations above probable effects, most likely contributed by wood/biomass burning.

  4. Rapid determination of iron oxide content in magnetically modified particulate materials

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Nýdlová, L.; Pospíšková, K.; Baldíková, E.; Maděrová, Z.; Šafaříková, Miroslava

    2016-01-01

    Roč. 26, June (2016), s. 114-117 ISSN 1674-2001 Institutional support: RVO:60077344 Keywords : magnetic iron oxide s * magnetic permeability meter * magnetically modified materials Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.621, year: 2016

  5. Determination of the solubility limiting solid of the selenium in the presence of iron under anoxic conditions

    International Nuclear Information System (INIS)

    Iida, Y.; Yamaguchi, T.; Tanaka, T.; Kitamura, A.; Nakayama, S.

    2009-01-01

    Dissolution experiments of selenium were performed from both under saturation and over saturation directions to determine the solubility limiting solid of selenium under the conditions which thermodynamically prefer the formation of ferroselite (FeSe 2 ). X-ray diffractometry (XRD) showed that FeSe 2 was formed in the over-saturation experiments. However, the ion activity products for the reaction of 0.5 FeSe 2 + H + + e - 0.5 Fe 2+ + HSe - , aFe 2+0.5 aHSe - a H+ -1 a e- -1 , obtained from both under saturation and over saturation directions were 3 to 4 orders of magnitude higher than the equilibrium constants calculated from existing thermodynamic data. The dependencies of the selenium concentration on pH, Eh and the iron concentration were better interpreted as a dissolution reaction of selenium solid (Se(s)) than the iron-selenium compounds. The equilibrium constant of: Se(s) + H + + 2e - = HSe - was determined to be logK 0 -7.46±0.11. This value agrees with the value of logK 0 = -7.62±0.06 calculated from existing thermodynamic data of crystalline selenium within errors. Because crystalline selenium was not identified in the solid phases by XRD, the solubility limiting solid would be amorphous or minor amount of crystalline selenium, even if the iron-selenium compound was formed. (authors)

  6. Substrate-induced antiferromagnetism of ultrathin iron overlayers on the iridium and rhodium (001) surfaces

    Czech Academy of Sciences Publication Activity Database

    Máca, František; Kudrnovský, Josef; Drchal, Václav; Turek, Ilja; Bengone, O.; Redinger, J.

    2009-01-01

    Roč. 11, - (2009), s. 38-40 ISSN 1642-6037 R&D Projects: GA ČR GA202/07/0456; GA MŠk OC09028 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z20410507 Keywords : iridium * rhodium * iron * magnetismus in thin layers * density functional calculations Subject RIV: BM - Solid Matter Physics ; Magnetism

  7. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... also are hoping to determine which iron supplements work best to treat iron-deficiency anemia in children who do not consume the daily recommended amount of iron. Read less Participate in NHLBI Clinical Trials We lead or sponsor many studies related to iron-deficiency anemia. See if you ...

  8. Influence of the radial spacing between cathodes on the surface composition of iron samples sintered by hollow cathode electric discharge

    Directory of Open Access Journals (Sweden)

    Brunatto S.F.

    2001-01-01

    Full Text Available The present work reports an investigation of the influence of the radial spacing between cathodes on the iron sintering process by hollow cathode electrical discharge, with surface enrichment of the alloying elements Cr and Ni. Pressed cylindrical samples of 9.5 mm diameter and density of 7.0 ± 0.1 g/cm³ were prepared by compaction of Ancorsteel 1000C iron powder. These samples, constituting the central cathode, were positioned concentrically in the interior of an external cathode machined from a tube of stainless steel AISI 310 (containing: 25% Cr, 16% Ni, 1.5% Mn, 1.5% Si, 0.03% C and the remainder Fe. Sintering was done at 1150 °C, for 120 min, utilizing radial spacings between the central and hollow cathodes of 3, 6 and 9 mm and a gas mixture of 80% Ar and 20% H2, with a flow rate of 5 cm³/s at a pressure of 3 Torr. The electric discharge was generated using a pulsed voltage power source, with a period of 200 mus. The radial spacing had only a slight influence on the quantity of atoms of alloying elements deposited and diffused on the surface of the sample. Analysis with a microprobe showed the presence of chrome (up to 4.0% and nickel (up to 3.0%, in at. % at the surface of the samples. This surface enrichment can be attributed to the mechanism of sputtering of the metallic atoms present in the external cathode, with the deposition of these elements on the sample surface and consequent diffusion within the sample.

  9. Iron Quadrangle, Brazil. Elemental concentration determined by k0-instrumental neutron activation analysis. Part 2. Kale samples

    International Nuclear Information System (INIS)

    Menezes, M.A.B.C.; Palmieri, H.E.L.; Leonel, L.V.; Nalini, H.A.Jr.; Jacimovic, R.

    2006-01-01

    The objective of this study was to evaluate the influence of mining activity on elemental concentrations in kale grown around a mining area. Two sites studied are in the Iron Quadrangle, Minas Gerais, Brazil, considered one of the richest mineral-bearing regions in the world. One site is near mineral exploration activity and the other is an ecological area. A comparator site outside the Iron Quadrangle was also analyzed. This work focused on the determination of the elemental concentrations in kale applying the k 0 -instrumental neutron activation analysis. As the Brazilian legislation specifies values for soil only, the results for kale were compared to the literature values and it was found that the vegetable does not present any health risks. (author)

  10. 57Fe Moessbauer spectroscopic study on surface products of thin iron plates exposed to ambient atmosphere as a means of environmental monitoring

    International Nuclear Information System (INIS)

    Matsuo, Motoyuki; Kobayashi, Takaaki

    1993-01-01

    Conversion electron and transmission Moessbauer spectroscopy were applied to the analysis of thin iron plates exposed to the ambient atmosphere. The degree of corrosion of the iron plates was classified into three categories according to the kind and thickness of rust evaluated by Moessbauer spectra. The severe corrosion took place in seaside and roadside areas. The medium corrosion was observed in urban areas, and the weak corrosion occurred in suburban and mountainous areas. This fact implies that the surface products of iron plates can successfully reflect the ambient atmosphere to which the plates were exposed. (orig.)

  11. Experimental determinations of the performances of heat transfer surfaces

    International Nuclear Information System (INIS)

    Pirovano, Alain; Viannay, Stephane; Mazeas, C.Y.

    1974-01-01

    With the help of flow schemes and of assumptions on the heat transfer, it is possible, in some cases, to predict the thermal and aerodynamical performances of a new heat transfer surface with moderate accuracy. These estimates, valid for an approximate classification of a new surface among known surfaces, are not accurate enough to be taken as a basis for the design of heat exchangers. In the present state of knowledge, the performances of a new heat transfer surface can only be determined accurately with experimental measurements. Bertin and Co have at their disposal two air test rigs especially designed for this purpose. The first one, more directly concerned with the measurements on tube bundles with fluid flow perpendicular to the generatrices of the tubes, is a semi-closed loop equipped with a high-efficiency ejector which amplifies the air flow rate supplied by an external source and thus allows high values of Reynolds number to be reached. The second one is adapted to other types of surfaces: tubes with external flow parallel to the generatrices, tubes with sophisticated cross section and with internal flow, compact surfaces with finned plates, etc. Both test rigs, the relevant equipment, the methods of data acquisition and of test results analysis are described in this paper. During the 5 past years, 60 configurations were tested. It was possible to compare some of the test results with the results of measurements performed later, on entire heat exchangers working with numbers of tubes, fluids, and temperature levels different from those prevailing during the tests on the small scale mock-up; the agreement is quite good [fr

  12. Colloidally stable surface-modified iron oxide nanoparticles: Preparation, characterization and anti-tumor activity

    Energy Technology Data Exchange (ETDEWEB)

    Macková, Hana [Institute of Macromolecular Chemistry, AS CR, Heyrovsky Sq. 2, 162 06 Prague 6 (Czech Republic); Horák, Daniel, E-mail: horak@imc.cas.cz [Institute of Macromolecular Chemistry, AS CR, Heyrovsky Sq. 2, 162 06 Prague 6 (Czech Republic); Donchenko, Georgiy Viktorovich; Andriyaka, Vadim Ivanovich; Palyvoda, Olga Mikhailovna; Chernishov, Vladimir Ivanovich [Palladin Institute of Biochemistry, NASU, 9 Leontovich St., 01601 Kiev (Ukraine); Chekhun, Vasyl Fedorovich; Todor, Igor Nikolaevich [R. E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology, NASU, 45 Vasylkivska St., 03022 Kiev (Ukraine); Kuzmenko, Oleksandr Ivanovich [Palladin Institute of Biochemistry, NASU, 9 Leontovich St., 01601 Kiev (Ukraine)

    2015-04-15

    Maghemite (γ-Fe{sub 2}O{sub 3}) nanoparticles were obtained by co-precipitation of Fe(II) and Fe(III) chlorides and subsequent oxidation with sodium hypochlorite and coated with poly(N,N-dimethylacrylamide-co-acrylic acid) [P(DMAAm-AA)]. They were characterized by a range of methods including transmission electron microscopy (TEM), elemental analysis, dynamic light scattering (DLS) and zeta potential measurements. The effect of superparamagnetic P(DMAAm-AA)-γ-Fe{sub 2}O{sub 3} nanoparticles on oxidation of blood lipids, glutathione and proteins in blood serum was detected using 2-thiobarbituric acid and the ThioGlo fluorophore. Finally, mice received magnetic nanoparticles administered per os and the antitumor activity of the particles was tested on Lewis lung carcinoma (LLC) in male mice line C57BL/6 as an experimental in vivo metastatic tumor model; the tumor size was measured and the number of metastases in lungs was determined. Surface-modified γ-Fe{sub 2}O{sub 3} nanoparticles showed higher antitumor and antimetastatic activities than commercial CuFe{sub 2}O{sub 4} particles and the conventional antitumor agent cisplatin. - Highlights: • Maghemite nanoparticles were prepared and characterized. • Poly(N,N-dimethylacrylamide-co-acrylic acid) coating was synthetized. • Blood lipid, glutathione and protein peroxidation/oxidation was determined. • Antitumor effect of coated particles on Lewis lung carcinoma in mice was observed.

  13. Absorption of Nickel, Chromium, and Iron by the Root Surface of Primary Molars Covered with Stainless Steel Crowns

    Directory of Open Access Journals (Sweden)

    David Keinan

    2010-01-01

    Full Text Available Objective. The purpose of this study was to analyze the absorption of metal ions released from stainless steel crowns by root surface of primary molars. Study Design. Laboratory research: The study included 34 primary molars, exfoliated or extracted during routine dental treatment. 17 molars were covered with stainless-steel crowns for more than two years and compared to 17 intact primary molars. Chemical content of the mesial or distal root surface, 1 mm apically to the crown or the cemento-enamel junction (CEJ, was analyzed. An energy dispersive X-ray spectrometer (EDS was used for chemical analysis. Results. Higher amounts of nickel, chromium, and iron (5-6 times were found in the cementum of molars covered with stainless-steel crowns compared to intact molars. The differences between groups were highly significant (<.001. Significance. Stainless-steel crowns release nickel, chromium, and iron in oral environment, and the ions are absorbed by the primary molars roots. The additional burden of allergenic metals should be reduced if possible.

  14. Effect of charged deep states in hydrogenated amorphous silicon on the behavior of iron oxides nanoparticles deposited on its surface

    International Nuclear Information System (INIS)

    Gmucova, Katarina; Weis, Martin; Nadazdy, Vojtech; Capek, Ignac; Satka, Alexander; Chitu, Livia; Cirak, Julius; Majkova, Eva

    2008-01-01

    Langmuir-Blodgett technique has been used for the deposition of ordered two-dimensional arrays of iron oxides (Fe 3 O 4 /Fe 2 O 3 ) nanoparticles onto the photovoltaic hydrogenated amorphous silicon (a-Si:H) thin film. Electric field at the a-Si:H/iron oxides nanoparticles interface was directly in the electrochemical cell modified by light soaking and bias voltage (negative or positive) pretreatment resulting in the change of the dominant type of charged deep states in the a-Si:H layer. Induced reversible changes in the nanoparticle redox behavior have been observed. We suggest two possible explanations of the data obtained, both of them are needed to describe measured electrochemical signals. The first one consists in the electrocatalytical effect caused by the defect states (negatively or positively charged) in the a-Si:H layer. The second one consists in the possibility to manipulate the nanoparticle cores in the prepared structure immersed in aqueous solution via the laser irradiation under specific bias voltage. In this case, the nanoparticle cores are assumed to be covered with surface clusters of heterovalent complexes created onto the surface regions with prevailing ferrous or ferric valency. Immersed in the high viscosity surrounding composed of the wet organic nanoparticle envelope these cores are able to perform a field-assisted pivotal motion. The local electric field induced by the deep states in the a-Si:H layer stabilizes their 'orientation ordering' in an energetically favourable position

  15. The determination of specific surface of sodium polyuranates

    International Nuclear Information System (INIS)

    Bilgin, B.; Atun, G.

    2002-01-01

    Three different sodium polyuranates were prepared by titration of uranyl nitrate with a sodium hydroxide solution labeled with 22 Na as the radiotracer. Polyuranates whose composition was *Na 2 O.7,5UO 3 .11H 2 O (sample A), *Na 2 O.4,3 UO 3 .4,7H 2 O (sample B), and *Na 2 O.2UO 3 .4H 2 O (sample C) were precipitated at pH 5.6, 8.5 and 11.2, respectively. The specific surface areas of these samples were determined by the BET method using methylene blue (MB) as the adsorbate. The sodium polyuranate surfaces were saturated by sequential adsorption of MB. The adsorption data gave an S-shaped isotherm and were fitted to the BET equation. The specific surface areas calculated from the BET isotherm decreased in order A > B > C. The isotope and ion exchange reactions between the sodium polyuranates and Li + , Na + , K + , Rb + , Cs + , Ca 2+ , Sr 2+ , and Ba 2+ ions were compared before and after MB coverage. The results showed that the isotope and ion exchange fractions decrease on the covered surfaces indicating particle diffusion mechanism dominated exchange reactions

  16. Structure determination by photoelectron diffraction of small molecules on surfaces

    International Nuclear Information System (INIS)

    Booth, N.A.

    1998-05-01

    The synchrotron radiation based technique of Photoelectron Diffraction (PhD) has been applied to three adsorption systems. Structure determinations, are presented for each system which involve the adsorption of small molecules on the low index {110} plane of single crystal Cu and Ni substrates. For the NH 3 -Cu(110) system PhD was successful in determining a N-Cu bondlength of 2.05 ± 0.03 A as well as values for the anisotropic vibrational amplitudes of the N and an expansion of the 1st to 2nd Cu substrate layer spacing from the bulk value of 0.08 ± 0.08 A. The most significant and surprising structural parameter determined for this system was that the N atom occupies an asymmetric adsorption site. Rather than being situated in the expected high symmetry atop site the N atom was found to be offset parallel to the surface by 0.37 ± 0.12 A in the [001] azimuth. In studying the glycine-Cu(110) system the adsorption structure of an amino-acid has been quantified. The local adsorption geometries of all the atoms involved in the molecule to surface bond have been determined. The glycine molecule is found to be bonded to the surface via both its amino and carboxylate functional groups. The molecule straddles two [11-bar0] rows of the Cu substrate. The two O atoms are found to be in identical sites both approximately atop Cu atoms on the [11-bar0] rows offset parallel to the surface by 0.80 ± 0.05 A in the [001] azimuth, the O-Cu bondlength was found to be 2.03 ± 0.05 A. The N atom was also found to adsorb in an approximately atop geometry but offset parallel to the surface by 0.24 ± 0.10A in the [11-bar0] direction, the N-Cu bondlength was found to be 2.05± 0.05 A. PhD was unsuccessful in determining the positions of the two C atoms that form a bridge between the two functional groups bonded to the surface due to difficulties in separating the two inequivalent contributions to the final intensity modulation function. For the CN-Ni(110) system both PhD and Near Edge

  17. Spectrophotometric determination of iron species using a combination of artificial neural networks and dispersive liquid–liquid microextraction based on solidification of floating organic drop

    International Nuclear Information System (INIS)

    Moghadam, Masoud Rohani; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh

    2011-01-01

    Highlights: ► Combination of DLLME-SFO/fiber optic-linear array detection/chemometric methods. ► Simultaneous determination of complexes with overlapping spectra. ► A novel DLLME-SFO method is proposed for extraction of iron species. ► The extracted iron species are simultaneous determined using PC-ANNs. ► The enhancement factor of 162 and 125 are achieved for Fe 3+ and Fe 2+ , respectively. - Abstract: A dispersive liquid–liquid microextraction based on solidification of floating organic drop (DLLME-SFO) and artificial neural networks method was developed for the simultaneous separation/preconcentration and speciation of iron in water samples. In this method, an appropriate mixture of ethanol (as the disperser solvent) and 1-undecanol (as the extracting solvent) containing appropriate amount of 2-thenoyltrifluoroacetone (TTA) (as the complexing agent) was injected rapidly into the water sample containing iron (II) and iron (III) species. At this step, the iron species interacted with the TTA and extracted into the 1-undecanol. After the phase separation, the absorbance of the extracted irons was measured in the wavelength region of 450–600 nm. The artificial neural networks were then applied for simultaneous determination of individual iron species. Under optimum conditions, the calibration graphs were linear in the range of 95–1070 μg L −1 and 31–350 μg L −1 with detection limits of 25 and 8 μg L −1 for iron (II) and iron (III), respectively. The relative standard deviations (R.S.D., n = 6) were lower than 4.2%. The enhancement factor of 162 and 125 were obtained for Fe 3+ and Fe 2+ ions, respectively. The procedure was applied to power plant drum water and several potable water samples; and accuracy was assessed through the recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry.

  18. Phytic Acid-to-Iron Molar Ratio Rather than Polyphenol Concentration Determines Iron Bioavailability in Whole-Cowpea Meal among Young Women

    NARCIS (Netherlands)

    Abizari, A.R.; Moretti, D.; Zimmerman, M.B.; Armar-Klemesu, M.; Brouwer, I.D.

    2012-01-01

    Limited data exist on iron absorption from NaFeEDTA and FeSO(4) in legume-based flours. The current study compared iron absorption from NaFeEDTA and FeSO(4) as fortificants within and between red and white varieties of cowpea with different concentrations of polyphenols (PP) but similar phytic acid

  19. Determination of trace impurities in high-purity iron using salting-out of polyoxyethylene-type surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Matsumiya, Hiroaki, E-mail: h-matsu@numse.nagoya-u.ac.jp [Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Sakane, Yuto; Hiraide, Masataka [Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2009-10-19

    To an iron sample solution was added polyoxyethylene-4-isononylphenoxy ether (PONPE, nonionic surfactant, average number of ethylene oxides 7.5) and the surfactant was aggregated by the addition of lithium chloride. The iron(III) matrix was collected into the condensed surfactant phase in >99.9% yields, leaving trace metals [e.g., Ti(IV), Cr(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II), and Bi(III)] in the aqueous phase. After removing the surfactant phase by centrifugation, the remaining trace metals were concentrated onto an iminodiacetic acid-type chelating resin. The trace metals were desorbed with dilute nitric acid for the determination by inductively coupled plasma-mass spectrometry or graphite-furnace atomic absorption spectrometry. The proposed separation method allowed the analysis of high-purity iron metals for trace impurities at low {mu}g g{sup -1} to ng g{sup -1} levels.

  20. Studies on the removal of interference of iron in the determination of uranium by direct titration with ammonium meta vanadate method

    International Nuclear Information System (INIS)

    Chavan, A.A.; Charyulu, M.M.

    2009-01-01

    To determine the uranium content in metal powder and alloys, routinely used method in NUMAC control Lab is dissolution of sample in 10 M phosphoric acid under heating and determination of uranium by ammonium meta vanadate method-visual indicator end point. If iron is present, it interferes quantitatively. The method is modified for removing the interference of iron by dissolving the samples in conc. phosphoric acid and Fe 2+ is quantitatively oxidized to Fe 3+ by nitric acid prior to analysis. (author)

  1. Environmental application of millimetre-scale sponge iron (s-Fe{sup 0}) particles (III): The effect of surface silver

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Yongming [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); South China Subcenter of State Environmental Dioxin Monitoring Center, Guangzhou 510655 (China); Innovative Laboratory for Environmental Functional Materials and Environmental Applications of Microwave Irradiation, Guangzhou 510655 (China); Yu, Yunjiang, E-mail: yuyunjiang@scies.org [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Wang, Xiaoyan [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Innovative Laboratory for Environmental Functional Materials and Environmental Applications of Microwave Irradiation, Guangzhou 510655 (China); Zhang, Sukun [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Liu, Runlong [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Innovative Laboratory for Environmental Functional Materials and Environmental Applications of Microwave Irradiation, Guangzhou 510655 (China); Fu, Jianping; Han, Jinglei; Fang, Jiande [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering (DBCEE), University of Cincinnati, Cincinnati, OH 45221-0012 (United States)

    2015-12-15

    Highlights: • Direct reductive deposition reaction achieves surfaced decoration of s-Fe{sup 0} particles. • Ag{sup 0}-s-Fe{sup 0} displays similar removal efficiency of PCP as compared to bimetal of nZVI. • Ag{sup 0}-s-Fe{sup 0} can be utilized under mild reaction condition compared to bimetal of nZVI. • The catalytic mechanism over Ag{sup 0}-s-Fe{sup 0} under US condition is elucidated. - Abstract: To enhance the dechlorination reactivity of millimetric sponge iron (s-Fe{sup 0}), a facile one-pot method was used to decorate s-Fe{sup 0} with Ag{sup +} ions under ambient conditions. The results recorded by X-ray diffraction patterns, X-ray photoelectron spectra and high-resolution transmission electron microscopy demonstrated that the growth of Ag{sup 0} was dominated primarily by (1 1 1) plane with a mean length of ∼20 nm. The roles of Ag{sup 0} loading, catalyst dosage, particle size, initial pH and contaminant concentration were assessed during the removal of pentachlorophenol (PCP). Catalyst recyclability was also studied. The results revealed that 3–5 mm s-Fe{sup 0} particles with 5 wt% Ag{sup 0} loading exhibited the best performance with a dose of 3.0 g per 60 mL PCP solution. In addition, the dechlorination of PCP followed two-step, pseudo-first-order reaction kinetics, and Ag{sup 0}-s-Fe{sup 0} was advantageous compared with bimetals of nanoscale zero-valent iron, iron power and iron flakes. The dechlorination mechanism of PCP over Ag{sup 0}-s-Fe{sup 0} was attributed to the surface Ag{sup 0} decoration, which catalyzed the formation of reactive hydrogen atoms for indirect reaction, and the direct electron transfer via Fe–Ag{sup 0} galvanic cells for direct reaction. This suggests that Ag-based bimetals of s-Fe{sup 0} have great potential in the pretreatment of organic halogen compounds in aqueous solution.

  2. Colloidally stable surface-modified iron oxide nanoparticles: preparation, characterization and anti-tumor activity

    Czech Academy of Sciences Publication Activity Database

    Macková, Hana; Horák, Daniel; Donchenko, G. V.; Andriyaka, V. I.; Palyvoda, O. M.; Chernishov, V. I.; Chekhun, V. F.; Todor, I. N.; Kuzmenko, O. I.

    2015-01-01

    Roč. 380, 15 April (2015), s. 125-131 ISSN 0304-8853. [International Conference on the Scientific and Clinical Applications of Magnetic Carriers /10./. Dresden, 10.06.2014-14.06.2014] R&D Projects: GA MŠk 7E12054; GA MŠk(CZ) LH14318; GA MŠk(CZ) ED1.1.00/02.0109 EU Projects: European Commission(XE) 259796 - DIATOOLS Institutional support: RVO:61389013 Keywords : iron oxide nanoparticle * poly(N,N-dimethylacrylamide-co-acrylic acid) * protein oxidation Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.357, year: 2015

  3. A novel surface protein of Trichomonas vaginalis is regulated independently by low iron and contact with vaginal epithelial cells

    Directory of Open Access Journals (Sweden)

    Chang T-H

    2006-01-01

    Full Text Available Abstract Background Trichomonosis caused by Trichomonas vaginalis is the number one, non-viral sexually transmitted disease (STD that affects more than 250 million people worldwide. Immunoglobulin A (IgA has been implicated in resistance to mucosal infections by pathogens. No reports are available of IgA-reactive proteins and the role, if any, of this class of antibody in the control of this STD. The availability of an IgA monoclonal antibody (mAb immunoreactive to trichomonads by whole cell (WC-ELISA prompted us to characterize the IgA-reactive protein of T. vaginalis. Results An IgA mAb called 6B8 was isolated from a library of mAbs reactive to surface proteins of T. vaginalis. The 6B8 mAb recognized a 44-kDa protein (TV44 by immunoblot analysis, and a full-length cDNA clone encoded a protein of 438 amino acids. Southern analysis revealed the gene (tv44 of T. vaginalis to be single copy. The tv44 gene was down-regulated at both the transcriptional and translational levels in iron-depleted trichomonads as well as in parasites after contact with immortalized MS-74 vaginal epithelial cells (VECs. Immunofluorescence on non-permeabilized organisms confirmed surface localization of TV44, and the intensity of fluorescence was reduced after parasite adherence to VECs. Lastly, an identical protein and gene were present in Tritrichomonas foetus and Trichomonas tenax. Conclusion This is the first report of a T. vaginalis gene (tv44 encoding a surface protein (TV44 reactive with an IgA mAb, and both gene and protein were conserved in human and bovine trichomonads. Further, TV44 is independently down-regulated in expression and surface placement by iron and contact with VECs. TV44 is another member of T. vaginalis genes that are regulated by at least two independent signaling mechanisms involving iron and contact with VECs.

  4. Gross alpha and gross beta determination in surface and groundwater water by liquid scintillation counting (LSC)

    International Nuclear Information System (INIS)

    Faria, Ligia S.; Moreira, Rubens M.

    2013-01-01

    The present study has used 40 samples of groundwater and surface water collected at four different sites along the period of one year in Brumadinho and Nova Lima, two municipalities in the State of Minas Gerais, Brazil, as part of a more extensive study aiming at determination of the natural radioactivity in the water used for domestic use. These two sites are inside an Environmental Protection Area is located in a region of very intensive iron ore exploration. In addition of mineral resources, the region has a geological characteristic that includes quartzitic conglomerates associated with uranium. Radioactivity levels were determined via liquid scintillation counting (LSC), a fast and high counting efficiency method that can be advantageously employed to determine gross alpha and gross beta activity in liquid samples. Previously to gross alpha and gross beta counting the samples were acidified with concentrated HNO 3 in the field. The technique involved a pre-concentration of the sample to obtain a low detection limit. Specific details of the employed methodology are commented. The results showed that concentrations of gross alpha natural activity and gross beta values ranged from less than the detection limit of the equipment (0.03 Bq.L -1 ) to 0.275 ± 0.05 Bq.L -1 for gross alpha. As regards gross beta, all samples were below the limit of detection. (author)

  5. Determination of Trace Iron in Red Wine by Isotope Dilution Mass Spectrometry Using Multiple-Collector Inductively Coupled Plasma Mass Spectrometry

    International Nuclear Information System (INIS)

    Zhou Tao; Wang Jun; Lu Hai; Zhou Yuanjing; Li Haifeng

    2009-01-01

    This paper introduces determination of trace iron in red wine certified reference material by isotope dilution mass spectrometry (IDMS) method using a multiplecollector inductively coupled plasma mass spectrometry, equipped with a hexapole collision cell. The measurement procedure of iron isotopic abundance ratios was deeply researched. Reduced polyatomic ion interferences to iron isotopes ion by collision reaction using Ar and H 2 gas, high precise isotopic abundance ratios were achieved. Two relative measurement methods (ICP-MS and ICP-OES) were used to analyze trace iron in red wine. The results are compared with IDMS results, which indicate that they are accordant. The uncertainty analyses include each uncertainty factor in whole experiment and the uncertainty of used certified reference material and it shows that the procedure blank is not neglectable to detect limit and precision of the method. The establishment of IDMS method for analysis of trace iron in red wine supports the certification of certified reference materials. (authors)

  6. Reducing phosphorus loading of surface water using iron-coated sand

    NARCIS (Netherlands)

    Groenenberg, J.E.; Chardon, W.J.; Koopmans, G.F.

    2013-01-01

    Phosphorus losses from agricultural soils is an important source of P in surface waters leading to surface water quality impairment. In addition to reducing P inputs, mitigation measures are needed to reduce P enrichment of surface waters. Because drainage of agricultural land by pipe drainage is an

  7. Iron oxidation kinetics and phosphorus immobilization at the groundwater-surface water interface

    NARCIS (Netherlands)

    van der Grift, Bas; Rozemeijer, Joachim; Griffioen, Jasper; van der Velde, Ype

    2014-01-01

    Eutrophication of freshwater environments following diffuse nutrient loads is a widely recognized water quality problem in catchments. Fluxes of non-point P sources to surface waters originate from surface runoff and flow from soil water and groundwater into surface water. The availability of P in

  8. Surface decoration of amine-rich carbon nitride with iron nanoparticles for arsenite (As{sup III}) uptake: The evolution of the Fe-phases under ambient conditions

    Energy Technology Data Exchange (ETDEWEB)

    Georgiou, Y., E-mail: yiannisgeorgiou@hotmail.com [Physics Department, University of Ioannina, Ioannina 45110 (Greece); Mouzourakis, E., E-mail: emouzou@cc.uoi.gr [Physics Department, University of Ioannina, Ioannina 45110 (Greece); Bourlinos, A.B., E-mail: bourlino@cc.uoi.gr [Physics Department, University of Ioannina, Ioannina 45110 (Greece); Regional Centre of Advanced Technologies and Materials, Faculty of Science, Department of Physical Chemistry and Experimental Physics, Palacky University in Olomouc, 77146 (Czech Republic); Zboril, R., E-mail: radek.zboril@upol.cz [Regional Centre of Advanced Technologies and Materials, Faculty of Science, Department of Physical Chemistry and Experimental Physics, Palacky University in Olomouc, 77146 (Czech Republic); Karakassides, M.A., E-mail: mkarakas@cc.uoi.gr [Department of Materials Science and Engineering, University of Ioannina, Ioannina 45110 (Greece); Douvalis, A.P., E-mail: adouval@uoi.gr [Physics Department, University of Ioannina, Ioannina 45110 (Greece); Bakas, Th., E-mail: tbakas@cc.uoi.gr [Physics Department, University of Ioannina, Ioannina 45110 (Greece); Deligiannakis, Y., E-mail: ideligia@cc.uoi.gr [Physics Department, University of Ioannina, Ioannina 45110 (Greece)

    2016-07-15

    Highlights: • Novel hybrid based on carbon nitride and iron nanoparticles (gC{sub 3}N{sub 4}-rFe). • gC{sub 3}N{sub 4}-rFe superior As{sup III} sorbent(76.5 mg g{sup −1}). • Surface complexation modeling of As{sup III} adsorption. • Dual mode EPR,monitoring of Fe{sup 2+} and Fe{sup 3+} evolution. - Abstract: A novel hybrid material (gC{sub 3}N{sub 4}-rFe) consisting of amine-rich graphitic carbon nitride (gC{sub 3}N{sub 4}), decorated with reduced iron nanoparticles (rFe) is presented. XRD and TEM show that gC{sub 3}N{sub 4}-rFe bears aggregation-free Fe-nanoparticles (10 nm) uniformly dispersed over the gC{sub 3}N{sub 4} surface. In contrast, non-supported iron nanoparticles are strongly aggregated, with non-uniform size distribution (20–100 nm). {sup 57}Fe-Mössbauer spectroscopy, dual-mode electron paramagnetic resonance (EPR) and magnetization measurements, allow a detailed mapping of the evolution of the Fe-phases after exposure to ambient O{sub 2}. The as-prepared gC{sub 3}N{sub 4}-rFe bears Fe{sup 2+} and Fe° phases, however only after long exposure to ambient O{sub 2}, a Fe-oxide layer is formed around the Fe° core. In this [Fe°/Fe-oxide] core-shell configuration, the gC{sub 3}N{sub 4}-rFe hybrid shows enhanced As{sup III} uptake capacity of 76.5 mg g{sup −1}, i.e., ca 90% higher than the unmodified carbonaceous support, and 300% higher than the non-supported Fe-nanoparticles. gC{sub 3}N{sub 4}-rFe is a superior As{sup III} sorbent i.e., compared to its single counterparts or vs. graphite/graphite oxide or activated carbon analogues (11–36 mg g{sup −1}). The present results demonstrate that the gC{sub 3}N{sub 4} matrix is not simply a net that holds the particles, but rather an active component that determines particle formation dynamics and ultimately their redox profile, size and surface dispersion homogeneity.

  9. Chemical equilibrium modeling of organic acids, pH, aluminum, and iron in Swedish surface waters.

    Science.gov (United States)

    Sjöstedt, Carin S; Gustafsson, Jon Petter; Köhler, Stephan J

    2010-11-15

    A consistent chemical equilibrium model that calculates pH from charge balance constraints and aluminum and iron speciation in the presence of natural organic matter is presented. The model requires input data for total aluminum, iron, organic carbon, fluoride, sulfate, and charge balance ANC. The model is calibrated to pH measurements (n = 322) by adjusting the fraction of active organic matter only, which results in an error of pH prediction on average below 0.2 pH units. The small systematic discrepancy between the analytical results for the monomeric aluminum fractionation and the model results is corrected for separately for two different fractionation techniques (n = 499) and validated on a large number (n = 3419) of geographically widely spread samples all over Sweden. The resulting average error for inorganic monomeric aluminum is around 1 µM. In its present form the model is the first internally consistent modeling approach for Sweden and may now be used as a tool for environmental quality management. Soil gibbsite with a log *Ks of 8.29 at 25°C together with a pH dependent loading function that uses molar Al/C ratios describes the amount of aluminum in solution in the presence of organic matter if the pH is roughly above 6.0.

  10. DETERMINATION OF IMPORTANCE EVALUATION FOR THE SURFACE EXPLORATORY STUDIES FACILITY

    International Nuclear Information System (INIS)

    C.J. Byrne

    2000-01-01

    This DIE applies to the surface facilities component of the Yucca Mountain Site Characterization Project (W) ESF. The ESF complex-including surface and subsurface accommodations--encompasses an area that is approximately six miles wide and nine miles long (approximately 30,000 acres total) (United States Department of Energy [DOE] 1997, p. 9.04). It is located on federally withdrawn lands, near the southwest border of the Nevada Test Site (NTS) in southern Nevada (DOE 1997, p. 9.04). Site characterization activities are conducted within the subsurface ESF to obtain the information necessary to determine whether the Yucca Mountain Site is suitable as a geologic repository for spent nuclear fuel and high-level radioactive waste. Most ESF surface facilities are located within the Conceptual Controlled Area Boundary (CCAB) (DOE 1997, p. 9.04), with the exception of the southeastern most portions of the H-Road and the Water Supply System. Various SBT activities are also conducted throughout the Yucca Mountain region as a part of the overall site-characterization effort. In general, the DIE for SBT Activities (Civilian Radioactive Waste Management System [CRWMS] Management and Operating Contractor [M andO] 1998a) evaluates activities associated with SBT. Potential test-to-test interference and waste isolation impacts associated with SBT activities are also evaluated in CRWMS M andO (1998a)

  11. DETERMINATION OF IMPORTANCE EVALUATION FOR THE SURFACE EXPLORATORY STUDIES FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    C.J. Byrne

    2000-07-25

    This DIE applies to the surface facilities component of the Yucca Mountain Site Characterization Project (W) ESF. The ESF complex-including surface and subsurface accommodations--encompasses an area that is approximately six miles wide and nine miles long (approximately 30,000 acres total) (United States Department of Energy [DOE] 1997, p. 9.04). It is located on federally withdrawn lands, near the southwest border of the Nevada Test Site (NTS) in southern Nevada (DOE 1997, p. 9.04). Site characterization activities are conducted within the subsurface ESF to obtain the information necessary to determine whether the Yucca Mountain Site is suitable as a geologic repository for spent nuclear fuel and high-level radioactive waste. Most ESF surface facilities are located within the Conceptual Controlled Area Boundary (CCAB) (DOE 1997, p. 9.04), with the exception of the southeastern most portions of the H-Road and the Water Supply System. Various SBT activities are also conducted throughout the Yucca Mountain region as a part of the overall site-characterization effort. In general, the DIE for SBT Activities (Civilian Radioactive Waste Management System [CRWMS] Management and Operating Contractor [M&O] 1998a) evaluates activities associated with SBT. Potential test-to-test interference and waste isolation impacts associated with SBT activities are also evaluated in CRWMS M&O (1998a).

  12. Determining the surface roughness coefficient by 3D Scanner

    Directory of Open Access Journals (Sweden)

    Karmen Fifer Bizjak

    2010-12-01

    Full Text Available Currently, several test methods can be used in the laboratory to determine the roughness of rock joint surfaces.However, true roughness can be distorted and underestimated by the differences in the sampling interval of themeasurement methods. Thus, these measurement methods produce a dead zone and distorted roughness profiles.In this paper a new rock joint surface roughness measurement method is presented, with the use of a camera-typethree-dimensional (3D scanner as an alternative to current methods. For this study, the surfaces of ten samples oftuff were digitized by means of a 3D scanner, and the results were compared with the corresponding Rock JointCoefficient (JRC values. Up until now such 3D scanner have been mostly used in the automotive industry, whereastheir use for comparison with obtained JRC coefficient values in rock mechanics is presented here for the first time.The proposed new method is a faster, more precise and more accurate than other existing test methods, and is apromising technique for use in this area of study in the future.

  13. Influence of particle size of wear metal on the spectrometric oil analysis programme (SOAP), demonstrated by the determination of iron by AAS

    Energy Technology Data Exchange (ETDEWEB)

    Klaegler, S.H.; Jantzen, E.

    1982-02-01

    The possibility that there might be a relation between particle size of wear metal and spectrometric determination, (e.g. of the iron content in used lubricating oils) has been examined. In this connection it had to be clarified from which particle size of the iron wear the Fe content determined by direct AAS (solution of the oil sample) is in agreement with the true value in the used oil. The determination of the absolute iron content was performed by a colorimetric method preceded by an incineration of the used oil. Contrary to other publications, in which work is based on spherical iron particles as a simulated wear, the test described here relates to true wear particles. To obtain the total iron wear from a gear oil it was filtered off from the used oil and afterwards separated into defined particle size ranges by a procedure specially developed for this purpose. The different groups of scaly particles, which were collected in this way, were then mixed homogeneously into fresh luboil samples according to their sizes. The determination of the iron content from these newly mixed luboil samples was carried out 1. by direct AAS, 2. by AAS after incineration of the oil samples and 3. by a colorimetric method (to obtain the absolute value of the iron content). The results showed a recovery of the iron of only 50% if the wear particles were bigger than about 2 ..mu..m. That means that the true value of the iron content in a used lubricating oil is found by direct AAS only if the particle size is <=1 ..mu..m.

  14. Iron deposition in modern and archaeological teeth

    Energy Technology Data Exchange (ETDEWEB)

    Williams, A.-M.M., E-mail: AnneMarie.Williams@utas.edu.au [School of Medicine, Private Bag 34, University of Tasmania, Hobart 7001 (Australia); Siegele, R. [Australian Nuclear Science and Technology Organisation, PMB 1, Menai, NSW 2234 (Australia)

    2014-09-15

    Iron surface concentrations and profile maps were measured on the enamel of archaeological and modern teeth to determine how iron is deposited in tooth enamel and if it was affected by the post-mortem environment. Teeth from Australian children who died in the second half of the 19th century were compared with contemporary teeth extracted for orthodontic purposes. Surface analysis of the teeth was performed using the 3 MV Van Der Graff Accelerator at The Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia. A small sample of teeth were then cut in the mid sagittal plane and analysed using ANSTO High Energy Heavy Ion Microprobe. Maps and linear profiles were produced showing the distribution of iron across the enamel. Results show that both the levels and distribution of iron in archaeological teeth is quite different to contemporary teeth, raising the suggestion that iron has been significantly altered by the post-mortem environment.

  15. Iron deposition in modern and archaeological teeth

    International Nuclear Information System (INIS)

    Williams, A.-M.M.; Siegele, R.

    2014-01-01

    Iron surface concentrations and profile maps were measured on the enamel of archaeological and modern teeth to determine how iron is deposited in tooth enamel and if it was affected by the post-mortem environment. Teeth from Australian children who died in the second half of the 19th century were compared with contemporary teeth extracted for orthodontic purposes. Surface analysis of the teeth was performed using the 3 MV Van Der Graff Accelerator at The Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia. A small sample of teeth were then cut in the mid sagittal plane and analysed using ANSTO High Energy Heavy Ion Microprobe. Maps and linear profiles were produced showing the distribution of iron across the enamel. Results show that both the levels and distribution of iron in archaeological teeth is quite different to contemporary teeth, raising the suggestion that iron has been significantly altered by the post-mortem environment

  16. Sol-gel based optical sensor for determination of Fe (II): a novel probe for iron speciation.

    Science.gov (United States)

    Samadi-Maybodi, Abdolraouf; Rezaei, Vida; Rastegarzadeh, Saadat

    2015-02-05

    A highly selective optical sensor for Fe (II) ions was developed based on entrapment of a sensitive reagent, 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ), in a silica sol-gel thin film coated on a glass substrate. The thin films fabricated based on tetraethoxysilane (TEOS) as precursor, sol-gel pH∼3, water:alkoxyde ratio of 4:1 and TPTZ concentration of 0.112 mol L(-1). The influence of sol-gel parameters on sensing behavior of the fabricated sensor was also investigated. The fabricated sensor can be used for determination of Fe (II) ion with an outstanding high selectivity over a dynamic range of 5-115 ng mL(-1) and a detection limit of 1.68 ng mL(-1). It also showed reproducible results with relative standard deviation of 3.5% and 1.27% for 10 and 90 ng mL(-1) of Fe (II), respectively, along with a fast response time of ∼120 s. Total iron also was determined after reduction of Fe (III) to Fe (II) using ascorbic acid as reducing agent. Then, the concentration of Fe (III) was calculated by subtracting the concentration of Fe (II) from the total iron concentration. Interference studies showed a good selectivity for Fe (II) with trapping TPTZ into sol-gel matrix and appropriately adjusting the structure of doped sol-gel. The sensor was compared with other sensors and was applied to determine iron in different water samples with good results. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Iodometric determination of peroxydiphosphate in the presence of copper(II) or iron(II) as catalyst.

    Science.gov (United States)

    Kapoor, S; Sharma, P D; Gupta, Y K

    1975-09-01

    Peroxydiphosphate can be determined iodometrically in the presence of a large excess of potassium iodide with copper(II) or iron(II) as catalyst through the operation of the Cu(II)/Cu(I) or Fe(II)/Fe(III) cycle. The method is applicable in HClO(4), H(2)SO(4), HCl and CH(3)COOH acid media in the range 0.1-1.0M studied. Nickel, manganese(II), cobalt(II), silver, chloride and phosphate are without effect.

  18. Ruthenium determination in new composite materials by coulometric titration with generated iron(2)

    International Nuclear Information System (INIS)

    Butakova, N.A.; Oganesyan, L.B.

    1983-01-01

    A coulometric technique is developed for ruthenium (4) titration with generated iron (2) in a mixture of hydrochloric-, sulfuric- and phosphoric acids with potentiometric and biammetric indication of the final titration point. Bi (3), Pd (2), Nb (5), Pt (4) Pb (2), Rh (3) do not interfere with the titration. Together with Ru (4) titrated are Ir (4), V (5), Au (3). The method is applied to analyze commercial samples of ruthenium dioxides, lead- and bismuth ruthenites, ruthenium pentafluorides containing 30-80% of ruthenium. The Ssub(r) values do not exceed 0.002

  19. Iron Quadrangle, Brazil. Elemental concentration determined by k0-instrumental neutron activation analysis. Part 1. Soil samples

    International Nuclear Information System (INIS)

    Menezes, M.A.B.C.; Palmieri, H.E.L.; Leonel, L.V.; Nalini, H.A.Jr.; Jacimovic, R.

    2006-01-01

    The Iron Quadrangle, Minas Gerais, Brazil, is rich in mineral occurrences and is considered one of the richest mineral-bearing regions in the world. Most investigations in this region have dealt with the determination of arsenic and mercury but so far few studies have been carried out aiming at determining other important elements. Having in mind the potential risk caused by mineral activities, this study was developed in order to assess the potential influence of the soil on foodstuffs. The soil samples were collected from three sites inside and outside the Iron Quadrangle. The samples were analyzed at the Laboratory for Neutron Activation Analysis, CDTN/CNEN by the k 0 -instrumental neutron activation analysis. This paper reports the elemental concentration determined in soil and emphasises the elements cited in the Brazilian environmental legislation for soil. This work also confirms the high elemental concentration of several minerals, however, it is difficult to distinguish the contamination from anthropogenic activities from the natural occurrence. (author)

  20. Effect of Carbon Content on the Properties of Iron-Based Powder Metallurgical Parts Produced by the Surface Rolling Process

    Directory of Open Access Journals (Sweden)

    Yan Zhao

    2018-01-01

    Full Text Available In recent years, the rolling densification process has become increasingly widely used to strengthen powder metallurgy parts. The original composition of the rolled powder metallurgy blank has a significant effect on the rolling densification technology. The present work investigated the effects of different carbon contents (0 wt. %, 0.2 wt. %, 0.45 wt. %, and 0.8 wt. % on the rolling densification. The selection of the raw materials in the surface rolling densification process was analyzed based on the pore condition, structure, hardness, and friction performance of the materials. The results show that the 0.8 wt. % carbon content of the surface rolling material can effectively improve the properties of iron-based powder metallurgy parts. The samples with 0.8 wt. % carbon have the highest surface hardness (340 HV0.1 and the lowest surface friction coefficient (0.35. Even if the dense layer depth is 1.13 mm, which is thinner than other samples with low carbon content, it also meets the requirements for powder metallurgy parts such as gears used in the auto industry.

  1. Cathode material and pulsed plasma treatment influence on the microstructure and microhardness of high-chromium cast iron surface

    Directory of Open Access Journals (Sweden)

    Юлія Геннадіївна Чабак

    2016-11-01

    Full Text Available The article presents an analysis of the cathode material and the pulse plasma treatment mode influence on the surface microstructure and microhardness of high chrome (15% Cr cast iron. The methods of metallographic analysis and microhardness measurements were used. It has been shown that pulsed plasma treatment at 4 kV voltage with the use of the electro-axial thermal accelerator results in surface modification with high microhardness 950-1050 HV50, and in the formation of the coating due to the transfer of the electrodes material. The specific features of using different cathode materials have been systematized. It has been found that graphite electrodes are not recommended to be used due to their low strength and fracture under plasma pulses. In case of using tungsten cathode a coating of small thickness (20-30 microns and having cracks has been formed on the specimen surface. The most expedient is to apply the electrodes with low melting point (such as killed St.3, which provides a high-quality state of treated surface and formation the protective crack-free coating of 80-100 microns thick. It has been found that as a result of the plasma pulsed treatment the enrichment of coating with carbon is likely to occur that results in microhardness increase. The prospects of this technology as well as its shortcomings have been described

  2. Expression, immunogenicity and variation of iron-regulated surface protein A from bovine isolates of Staphylococcus aureus.

    Science.gov (United States)

    Misra, Neha; Wines, Tyler F; Knopp, Colton L; McGuire, Mark A; Tinker, Juliette K

    2017-05-01

    Staphylococcus aureus iron-regulated surface protein A (IsdA) is a fibrinogen and fibronectin adhesin that also contributes to iron sequestration and resistance to innate immunity. IsdA is conserved in human isolates and has been investigated as a human vaccine candidate. Here we report the expression of isdA, the efficacy of anti-IsdA responses and the existence of IsdA sequence variants from bovine Staphylococcus. Clinical staphylococci were obtained from US dairy farms and assayed by PCR for the presence and expression of isdA. isdA-positive species from bovines included S. aureus, S. haemolyticus and S. chromogenes. Immunoassays on bovine milk and serum confirmed the induction and opsonophagocytic activity of anti-IsdA humoral responses. The variable region of isdA was sequenced and protein alignments predicted the presence of two main variants consistent with those from human S. aureus. Mouse antibodies against one IsdA variant reduced staphylococcal binding to fibronectin in vitro in an isotype-dependent manner. Purified IsdA variants bound distinctly to fibronectin and fibrinogen. Our findings demonstrate that variability within the C-terminus of this adhesin affects immune reactivity and binding specificity, but are consistent with the significance of IsdA in bovine disease and relevant for vaccine development. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Expression, immunogenicity and variation of iron-regulated surface protein A from bovine isolates of Staphylococcus aureus

    Science.gov (United States)

    Misra, Neha; Wines, Tyler F.; Knopp, Colton L.; McGuire, Mark A.; Tinker, Juliette K.

    2017-01-01

    Abstract Staphylococcus aureus iron-regulated surface protein A (IsdA) is a fibrinogen and fibronectin adhesin that also contributes to iron sequestration and resistance to innate immunity. IsdA is conserved in human isolates and has been investigated as a human vaccine candidate. Here we report the expression of isdA, the efficacy of anti-IsdA responses and the existence of IsdA sequence variants from bovine Staphylococcus. Clinical staphylococci were obtained from US dairy farms and assayed by PCR for the presence and expression of isdA. isdA-positive species from bovines included S. aureus, S. haemolyticus and S. chromogenes. Immunoassays on bovine milk and serum confirmed the induction and opsonophagocytic activity of anti-IsdA humoral responses. The variable region of isdA was sequenced and protein alignments predicted the presence of two main variants consistent with those from human S. aureus. Mouse antibodies against one IsdA variant reduced staphylococcal binding to fibronectin in vitro in an isotype-dependent manner. Purified IsdA variants bound distinctly to fibronectin and fibrinogen. Our findings demonstrate that variability within the C-terminus of this adhesin affects immune reactivity and binding specificity, but are consistent with the significance of IsdA in bovine disease and relevant for vaccine development. PMID:28430959

  4. Surface chemistry and electrocatalytic behaviour of tetra-carboxy substituted iron, cobalt and manganese phthalocyanine monolayers on gold electrode

    International Nuclear Information System (INIS)

    Mashazi, Philani N.; Westbroek, Philippe; Ozoemena, Kenneth I.; Nyokong, Tebello

    2007-01-01

    Surface chemistry and electrocatalytic properties of self-assembled monolayers of metal tetra-carboxylic acid phthalocyanine complexes with cobalt (Co), iron (Fe) and manganese (Mn) as central metal ions have been studied. These phthalocyanine molecules are immobilized on gold electrode via the coupling reaction between the ring substituents and pre-formed mercaptoethanol self-assembled monolayer (Au-ME SAM). X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed chemisorption of mercaptoethanol via sulfur group on gold electrode and also coupling reaction between phthalocyanines and Au-ME SAM. Electrochemical parameters of the immobilized molecules show that these molecules are densely packed with a perpendicular orientation. The potential applications of the gold modified electrodes were investigated towards L-cysteine detection and the analysis at phthalocyanine SAMs. Cobalt and iron tetra-carboxylic acid phthalocyanine monolayers showed good oxidation peak for L-cysteine at potentials where metal oxidation (M III /M II ) takes place and this metal oxidation mediates the catalytic oxidation of L-cysteine. Manganese tetra-carboxylic acid phthalocyanine monolayer also exhibited a good catalytic oxidation peak towards L-cysteine at potentials where Mn IV /Mn III redox peak occurs and this redox peak mediates L-cysteine oxidation. The analysis of cysteine at phthalocyanine monolayers displayed good analytical parameters with good detection limits of the orders of 10 -7 mol L -1 and good linearity for a studied concentration range up to 60 μmol L -1

  5. Microstructure and Wear Behavior of TiC Coating Deposited on Spheroidized Graphite Cast Iron Using Laser Surfacing

    Directory of Open Access Journals (Sweden)

    E. R. I. Mahmoud

    2014-10-01

    Full Text Available Spheroidal graphite cast iron was laser cladded with TiC powder using a YAG fiber laser at powers of 700, 1000, 1500 and 2000 W. The powder was preplaced on the surface of the specimens with 0.5 mm thickness. Sound cladding and fusion zones were observed at 700, 1000 and 1500 W powers. However, at 2000 W, cracking was observed in the fusion zone. At 700 W, a build-up zone consisted of fine TiC dendrites inside a matrix composed of martensite, cementite (Fe3C, and some blocks of retained austenite was observed. In this zone, all graphite nodules were totally melted. In the fusion zone, some undissolved and partially dissolved graphite nodules appeared in a matrix containing bainite, ferrite, martensite and retained austenite. At 1500 W, the fusion zone had more iron carbides and ferrite, and the HAZ consisted of martensitic structure. At 2000 W, the build-up zone was consisted of TiC particles precipitated in a matrix of eutectic carbides, martensite plus an inter-lamellar retained austenite. The hardness of the cladded area was remarkably improved (1330 HV in case of 700 W: 5.5 times of the hardness of substrate

  6. Effect of surface charge and agglomerate degree of magnetic iron oxide nanoparticles on KB cellular uptake in vitro.

    Science.gov (United States)

    Ge, Yuqing; Zhang, Yu; Xia, Jingguang; Ma, Ming; He, Shiying; Nie, Fang; Gu, Ning

    2009-10-15

    We synthesized three types of magnetic iron oxide nanoparticles (MNPs), which were meso-2,3-dimercaptosuccinic acid (DMSA) coated MNPs (DMSA@MNPs, 17.3+/-4.8 nm, negative charge), chitosan (CS) coated MNPs (CS@MNPs, 16.5+/-6.1 nm, positive charge) and magnetic nanoparticles agglomerates, formed by electronic aggregation between DMSA@MNPs and CS (CS-DMSA@MNPs, 85.7+/-72.9 nm, positive charge) respectively. The interactions of these MNPs with Oral Squamous Carcinoma Cell KB were investigated. The results showed that cellular uptakes of MNPs were on the dependence of incubation time, nanoparticles concentration and nanoparticles properties such as surface charge, size, etc. The cellular uptake was enhanced with the increase of incubation time and nanoparticles concentration. Although all MNPs could enter to cells, we observed apparent differences in the magnitude of nanoparticles uptaken. The cellular uptake of CS-DMSA@MNPs by KB cells was the highest and that of DMSA@MNPs was the lowest among the three types of MNPs. The same conclusions were drawn via the reduction of water proton relaxation times T(2)(*), resulting from the different iron load of labeled cells using a 1.5T clinical MR imager. The finding of this study will have implications in the chemical design of nanomaterials for biomedical applications.

  7. Investigation of iron(III) reduction and trace metal interferences in the determination of dissolved iron in seawater using flow injection with luminol chemiluminescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Ussher, Simon J. [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Milne, Angela [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Department of Oceanography, Florida State University, Tallahassee, FL 32306-4320 (United States); Landing, William M. [Department of Oceanography, Florida State University, Tallahassee, FL 32306-4320 (United States); Attiq-ur-Rehman, Kakar [Department of Chemistry, University of Balochistan, Quetta (Pakistan); Seguret, Marie J.M.; Holland, Toby [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Achterberg, Eric P. [National Oceanography Centre, University of Southampton, European Way, Southampton SO14 3ZH (United Kingdom); Nabi, Abdul [Department of Chemistry, University of Balochistan, Quetta (Pakistan); Worsfold, Paul J., E-mail: pworsfold@plymouth.ac.uk [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

    2009-10-12

    A detailed investigation into the performance of two flow injection-chemiluminescence (FI-CL) manifolds (with and without a preconcentration column) for the determination of sub-nanomolar dissolved iron (Fe(II) + Fe(III)), following the reduction of Fe(III) by sulphite, in seawater is described. Kinetic experiments were conducted to examine the efficiency of reduction of inorganic Fe(III) with sulphite under different conditions and a rigorous study of the potential interference caused by other transition metals present in seawater was conducted. Using 100 {mu}M concentrations of sulphite a reduction time of 4 h was sufficient to quantitatively reduce Fe(III) in seawater. Under optimal conditions, cobalt(II) and vanadium(IV)/(III) were the major positive interferences and strategies for their removal are reported. Specifically, cobalt(II) was masked by the addition of dimethylglyoxime to the luminol solution and vanadium(IV) was removed by passing the sample through an 8-hydroxyquinoline column in a low pH carrier stream. Manganese(II) also interfered by suppression of the CL response but this was not significant at typical open ocean concentrations.

  8. Assessment of Pb (II Removal from Aqueous Solutions by Ascorbic Acid-stabilized Zero-valent Iron Nanoparticles Using Response Surface Methodology (RSM

    Directory of Open Access Journals (Sweden)

    Mohaddeseh Savasari

    2017-07-01

    Full Text Available The growing pollution of water resources and the limited availability of water supplies have led to a growing interest by researchers to develop novel methods of water remediation and reuse. One such method is the use of ascorbic acid-stabilized zero-valent iron nanoparticles (AAS-ZVIN for the removal of lead (Pb from aqueous solutions. Using zero-valent iron nanoparticles stabilized with acid ascorbic under aerobic conditions, the present study was conducted to assess the efficiency of Pb removal from aqueous solutions and its optimization by the response surface methodology (RSM. For this purpose, use was made of the central composite design and the response surface methodology with the four input variables of ASS- ZVIN dose (0.5, 1, and 2 g L-1, pH (2, 5, and 7, contact time (5, 20, and 60 min, and initial Pb concentration (5, 10, and 20 mg L-1 to determine the optimal conditions for the process. Numerical optimization revealed that the optimum conditions for Pb removal (97.93% included an ASS-ZVIN dose of 2 g L-1, an initial Pb (II concentration of 25 mg L-1, a contact time of 60 min, and an initial solution pH of 7. The results also imply that not only does ASS-ZVIN offer a good potential for the remediation of water bodies contaminated with Pb, given its high reactivity for Pb removal, but that  the RSM optimization process can be successfully employed for the optimization of the process in question.

  9. Formation of coatings from a liquid phase on the surface of iron-base alloys

    Directory of Open Access Journals (Sweden)

    A. Tatarek

    2008-12-01

    Full Text Available The study discloses the present state of the art regarding the technology and investigations of the phenomena that take place during the formation and growth of aluminum and zinc coatings hot-dip formed on iron products. In its cognitive aspect, the study offers an in-depth analysis of the partial processes that proceed in metal bath at the solid body – liquid metal interface. It is expected that the present study will help in a more detailed description of the respective phenomena and in full explanation of the mechanism of the coating growth, taking as an example the growth of aluminum coatings. The obtained results can serve as a background for some general conclusions regarding the thickness evolution process in other hot-dip coatings.

  10. Analysis of the global ocean sampling (GOS) project for trends in iron uptake by surface ocean microbes.

    Science.gov (United States)

    Toulza, Eve; Tagliabue, Alessandro; Blain, Stéphane; Piganeau, Gwenael

    2012-01-01

    Microbial metagenomes are DNA samples of the most abundant, and therefore most successful organisms at the sampling time and location for a given cell size range. The study of microbial communities via their DNA content has revolutionized our understanding of microbial ecology and evolution. Iron availability is a critical resource that limits microbial communities' growth in many oceanic areas. Here, we built a database of 2319 sequences, corresponding to 140 gene families of iron metabolism with a large phylogenetic spread, to explore the microbial strategies of iron acquisition in the ocean's bacterial community. We estimate iron metabolism strategies from metagenome gene content and investigate whether their prevalence varies with dissolved iron concentrations obtained from a biogeochemical model. We show significant quantitative and qualitative variations in iron metabolism pathways, with a higher proportion of iron metabolism genes in low iron environments. We found a striking difference between coastal and open ocean sites regarding Fe(2+) versus Fe(3+) uptake gene prevalence. We also show that non-specific siderophore uptake increases in low iron open ocean environments, suggesting bacteria may acquire iron from natural siderophore-like organic complexes. Despite the lack of knowledge of iron uptake mechanisms in most marine microorganisms, our approach provides insights into how the iron metabolic pathways of microbial communities may vary with seawater iron concentrations.

  11. Spectrophotometric determination of ethionamide in pharmaceuticals using Folin–Ciocalteu reagent and iron(III-ferricyanide as chromogenic agents

    Directory of Open Access Journals (Sweden)

    Nagib A.S. Qarah

    2017-09-01

    Full Text Available Two simple and sensitive spectrophotometric methods are described for the determination of ethionamide (ETM in pure drug and tablets. The first method is based on the reduction of Folin–Ciocalteu (F–C reagent by ETM in sodium carbonate medium to form a blue coloured complex, which was measured at 760 nm (Molybdenum–tungsten blue method. In the second method (Prussian blue method, iron(III was reduced to iron(II by ETM in HCl medium, in which iron(II was complexed with ferricyanide, and the resulting Prussian blue was also measured at 760 nm. The absorbance measured in each case was related to the ETM concentration. The experimental conditions were carefully studied and optimised. Beer's law was obeyed in concentration ranges of 1–40 μg/ml and 0.2–4.0 μg/ml with the Molybdenum-tungsten blue method and the Prussian blue method, respectively, with corresponding molar absorptivity values of 5.72 × 103 and 3.18 × 104 l/(mol·cm. The limits of detection (LOD and quantification (LOQ were 0.09 and 0.27 μg/ml for the Molybdenum-tungsten blue method and 0.01 and 0.04 μg/ml for the Prussian blue method. Within-day and between-day relative standard deviations (%RSD at three different concentration levels were <3%, and the respective relative errors (%RE were ≤2%, implying good accuracy and precision of the methods. The proposed methods were successfully applied to the determination of ETM in bulk powder and tablets, and the results demonstrated that the methods were as accurate and precise as the official method.

  12. Use of neutron capture gamma radiation for determining grade of iron ore in blast holes and exploration holes

    International Nuclear Information System (INIS)

    Eisler, P.L.; Huppert, P.; Mathew, P.J.; Wylie, A.W.; Youl, S.F.

    1977-01-01

    Neutron radiative capture and neutron-neutron logging have been applied to determining the grade of ore in dry blast holes and a dry exploration hole drilled into a layered iron deposit. Both thermal and epithermal neutron responses were measured as well as the gamma-ray responses due to neutron capture by iron and by hydrogen present in hydrated minerals. The results were fitted by a stepwise multiple linear regression technique to give expressions for mean grade of ore in the drill hole and 95% confidence intervals for estimation of this mean. For an overall range of ore grades of 20-68% Fe and a mean grade of 63% Fe, the confidence interval for prediction of mean grade for the neutron-gamma technique was 0.3% Fe for pooled data from all five blast holes and 0.8% Fe for a single hole. It was also shown that for this type of layered deposit a simpler neutron-neutron log incorporating simultaneous measurement of both thermal and epithermal neutron responses gave almost as good a grade prediction result for pooled results from five drill holes, namely 63+-0.4% Fe, as that obtained by the neutron-gamma technique. The results of both types of log are compared with those obtained by the spectral gamma-ray backscattering [Psub(z)] technique, or by logging of natural gamma radiations from the shale component of the ore. From this comparison conclusions are drawn regarding the most suitable technique to employ for determining grade of iron ore in various practical logging situations. (author)

  13. Iron oxides characterization by Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Basurto Sanchez, R.

    1993-01-01

    In this work rust development on low carbon wire surface after the conformation process at different temperatures was studied by Moessbauer spectroscopy. The characterization was made by determining the following spectral parameters; 1) Quadrupole splitting, 2) Isomer shift, and 3) Magnetic splitting. The area quantification determined the percentage amount of three different iron oxides. These iron oxides were: a) Wustite (Fe O), b) Hematite (Fe 2 O 3 ), and c) Magnetite (Fe 3 O 4 ) which were present in the rust studied. With the results it was possible to establish the best temperature to favor the development of each of these iron oxides. (Author)

  14. Inhibition of nitrate reduction by NaCl adsorption on a nano-zero-valent iron surface during a concentrate treatment for water reuse.

    Science.gov (United States)

    Hwang, Yuhoon; Kim, Dogun; Shin, Hang-Sik

    2015-01-01

    Nanoscale zero-valent iron (NZVI) has been considered as a possible material to treat water and wastewater. However, it is necessary to verify the effect of the matrix components in different types of target water. In this study, different effects depending on the sodium chloride (NaCl) concentration on reductions of nitrates and on the characteristics of NZVI were investigated. Although NaCl is known as a promoter of iron corrosion, a high concentration of NaCl (>3 g/L) has a significant inhibition effect on the degree of NZVI reactivity towards nitrate. The experimental results were interpreted by a Langmuir-Hinshelwood-Hougen-Watson reaction in terms of inhibition, and the decreased NZVI reactivity could be explained by the increase in the inhibition constant. As a result of a chloride concentration analysis, it was verified that 7.7-26.5% of chloride was adsorbed onto the surface of NZVI. Moreover, the change of the iron corrosion product under different NaCl concentrations was investigated by a surface analysis of spent NZVI. Magnetite was the main product, with a low NaCl concentration (0.5 g/L), whereas amorphous iron hydroxide was observed at a high concentration (12 g/L). Though the surface was changed to permeable iron hydroxide, the Fe(0) in the core was not completely oxidized. Therefore, the inhibition effect of NaCl could be explained as the competitive adsorption of chloride and nitrate.

  15. Antiphase Fermi-surface modulations accompanying displacement excitation in a parent compound of iron-based superconductors

    Science.gov (United States)

    Okazaki, Kozo; Suzuki, Hakuto; Suzuki, Takeshi; Yamamoto, Takashi; Someya, Takashi; Ogawa, Yu; Okada, Masaru; Fujisawa, Masami; Kanai, Teruto; Ishii, Nobuhisa; Itatani, Jiro; Nakajima, Masamichi; Eisaki, Hiroshi; Fujimori, Atsushi; Shin, Shik

    2018-03-01

    We investigate the transient electronic structure of BaFe2As2 , a parent compound of iron-based superconductors, by time- and angle-resolved photoemission spectroscopy. In order to probe the entire Brillouin zone, we utilize extreme ultraviolet photons and observe photoemission intensity oscillation with the frequency of the A1 g phonon which is antiphase between the zone-centered hole Fermi surfaces (FSs) and zone-cornered electron FSs. We attribute the antiphase behavior to the warping in one of the zone-centered hole FSs accompanying the displacement of the pnictogen height and find that this displacement is the same direction as that induced by substitution of P for As, where superconductivity is induced by a structural modification without carrier doping in this system.

  16. Effect of Binder and Mold parameters on Collapsibility and Surface Finish of Gray Cast Iron No-bake Sand Molds

    Science.gov (United States)

    Srinivasulu Reddy, K.; Venkata Reddy, Vajrala; Mandava, Ravi Kumar

    2017-08-01

    Chemically bonded no-bake molds and cores have good mechanical properties and produce dimensionally accurate castings compared to green sand molds. Poor collapsibility property of CO2 hardened sodium silicate bonded sand mold and phenolic urethane no-bake (PUN) binder system, made the reclamation of the sands more important. In the present work fine silica sand is mixed with phenolic urethane no-bake binder and the sand sets in a very short time within few minutes. In this paper it is focused on optimizing the process parameters of PUN binder based sand castings for better collapsibility and surface finish of gray cast iron using Taguchi design. The findings were successfully verified through experiments.

  17. The Impact of Iron Adsorption on the Electronic and Photocatalytic Properties of the Zinc Oxide (0001 Surface: A First-Principles Study

    Directory of Open Access Journals (Sweden)

    Jingsi Cheng

    2018-03-01

    Full Text Available The structural stability, electronic structure, and optical properties of an iron-adsorbed ZnO (0001 surface with three high-symmetry adsorption sites are investigated with first-principle calculations on the basis of density functional theory and the Hubbard-U method. It is found that the iron adatom in the H3 adsorption site of ZnO (0001 surface has the lowest adsorption energy of −5.665 eV compared with T4 and Top sites. For the Top site, compared with the pristine ZnO (0001 surface, the absorption peak located at 1.17 eV has a red shift, and the elevation of the absorption coefficient is more pronounced in the visible-light region, because the Fe-related levels are introduced in the forbidden band and near the Fermi level. The electrostatic potential computation reveals that the work function of the ZnO (0001 surface is significantly decreased from 2.340 to 1.768 eV when iron is adsorbed on the Top site. Furthermore, the degradation mechanism based on the band structure is analyzed. It can be concluded that the adsorption of iron will promote the separation of photoinduced carriers, thus improving the photocatalytic activity of ZnO (0001 surface. Our study benefits research on the photocatalytic activity of ZnO and the utilization rate of solar energy.

  18. The Impact of Iron Adsorption on the Electronic and Photocatalytic Properties of the Zinc Oxide (0001) Surface: A First-Principles Study.

    Science.gov (United States)

    Cheng, Jingsi; Wang, Ping; Hua, Chao; Yang, Yintang; Zhang, Zhiyong

    2018-03-12

    The structural stability, electronic structure, and optical properties of an iron-adsorbed ZnO (0001) surface with three high-symmetry adsorption sites are investigated with first-principle calculations on the basis of density functional theory and the Hubbard-U method. It is found that the iron adatom in the H₃ adsorption site of ZnO (0001) surface has the lowest adsorption energy of -5.665 eV compared with T₄ and Top sites. For the Top site, compared with the pristine ZnO (0001) surface, the absorption peak located at 1.17 eV has a red shift, and the elevation of the absorption coefficient is more pronounced in the visible-light region, because the Fe-related levels are introduced in the forbidden band and near the Fermi level. The electrostatic potential computation reveals that the work function of the ZnO (0001) surface is significantly decreased from 2.340 to 1.768 eV when iron is adsorbed on the Top site. Furthermore, the degradation mechanism based on the band structure is analyzed. It can be concluded that the adsorption of iron will promote the separation of photoinduced carriers, thus improving the photocatalytic activity of ZnO (0001) surface. Our study benefits research on the photocatalytic activity of ZnO and the utilization rate of solar energy.

  19. Methodology for determination of trace elements in mineral phases of iron banded formation by LA-ICP-MS

    International Nuclear Information System (INIS)

    Sousa, Denise V.M. de; Nalini Junior, Herminio A.; Sampaio, Geraldo M.S.; Abreu, Adriana T. de; Lana, Cristiano de C.

    2015-01-01

    The study of the chemical composition of mineral phases of iron formation (FF), especially of trace elements, is an important tool in the understanding of the genesis of these rocks and the contribution of the phases in the composition of whole rock. Low mass fraction of such elements in the mineral phases present in this rock type requires a suitable analytical procedure. The laser ablation technique coupled with ICP-MS (LA-ICP-MS) has been widely used for determination of trace elements in geological samples. Thus, the aim of this study is to develop calibration curves for determination of trace elements (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) in mineral phases of banded iron formations by LA-ICP-MS. Several certified reference materials (CRM) were used for calibrate the equipment. The analytical conditions were checked by CRM NIST SRM 614. The results were satisfactory, since the curves showed good linearity coefficients, good accuracy and precision of results. (author)

  20. A novel type of electrochemical sensor based on ferromagnetic carbon-encapsulated iron nanoparticles for direct determination of hemoglobin in blood samples.

    Science.gov (United States)

    Matysiak, Edyta; Donten, Mikolaj; Kowalczyk, Agata; Bystrzejewski, Michal; Grudzinski, Ireneusz P; Nowicka, Anna M

    2015-02-15

    An effective, fast, facile and direct electrochemical method of determination of hemoglobin (Hb) in blood sample without any sample preparation is described. The method is accomplished by using the ferromagnetic electrode modifier (carbon-encapsulated iron nanoparticles) and an external magnetic field. The successful voltammetric determination of hemoglobin is achieved in PBS buffer as well as in the whole blood sample. The obtained results show the excellent electroactivity of Hb. The measurements are of high sensitivity and good reproducibility. The detection limit is estimated to be 0.7 pM. The electrochemical determination data were compared with the gravimetric data obtained with a quartz crystal microbalance. The agreement between these results is very good. The changes of the electrode surface morphology before and after Hb detection are monitored by electron microscopy. The functionality of the electrochemical sensor is tested with human and rat blood samples. The concentration of hemoglobin in the blood samples determined by using voltammetric/gravimetric detection is in perfect agreement with the data obtained from typical clinical analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Health and Human Development, we are investigating how best to treat premature newborns with low hemoglobin levels. ... are hoping to determine which iron supplements work best to treat iron-deficiency anemia in children who ...

  2. Effects of 1000 C oxide surfaces on room temperature aqueous corrosion and environmental embrittlement of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, R.A.; Perrin, R.L. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering

    1997-12-01

    Results of electrochemical aqueous-corrosion studies at room temperature indicate that retained in-service-type high-temperature surface oxides (1000 C in air for 24 hours) on FA-129, FAL and FAL-Mo iron aluminides cause major reductions in pitting corrosion resistance in a mild acid-chloride solution designed to simulate aggressive atmospheric corrosion. Removal of the oxides by mechanical grinding restores the corrosion resistance. In a more aggressive sodium tetrathionate solution, designed to simulate an aqueous environment contaminated by sulfur-bearing combustion products, only active corrosion occurs for both the 1000 C oxide and mechanically cleaned surfaces at FAL. Results of slow-strain-rate stress-corrosion-cracking tests on FA-129, FAL and FAL-Mo at free-corrosion and hydrogen-charging potentials in the mild acid chloride solution indicate somewhat higher ductilities (on the order of 50%) for the 1000 C oxides retard the penetration of hydrogen into the metal substrates and, consequently, are beneficial in terms of improving resistance to environmental embrittlement. In the aggressive sodium tetrathionate solution, no differences are observed in the ductilities produced by the 1000 C oxide and mechanically cleaned surfaces for FAL.

  3. Surface properties of self-assembled monolayer films of tetra-substituted cobalt, iron and manganese alkylthio phthalocyanine complexes

    Energy Technology Data Exchange (ETDEWEB)

    Akinbulu, Isaac Adebayo; Khene, Samson [Department of Chemistry, Rhodes University, Grahamstown 6140 (South Africa); Nyokong, Tebello, E-mail: t.nyokong@ru.ac.z [Department of Chemistry, Rhodes University, Grahamstown 6140 (South Africa)

    2010-09-30

    Self-assembled monolayer (SAM) films of iron (SAM-1), cobalt (SAM-2) and manganese (SAM-3) phthalocyanine complexes, tetra-substituted with diethylaminoethanethio at the non-peripheral positions, were formed on gold electrode in dimethylformamide (DMF). Electrochemical, impedimentary and surface properties of the SAM films were investigated. Cyclic voltammetry was used to investigate the electrochemical properties of the films. Ability of the films to inhibit common faradaic processes on bare gold surface (gold oxidation, solution redox chemistry of [Fe(H{sub 2}O){sub 6}]{sup 3+}/[Fe(H{sub 2}O){sub 6}]{sup 2+} and underpotential deposition (UDP) of copper) was investigated. Electrochemical impedance spectroscopy (EIS), using [Fe(CN){sub 6}]{sup 3-/4-} redox process as a probe, offered insights into the electrical properties of the films/electrode interfaces. Surface properties of the films were probed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). The films were employed for the electrocatalytic oxidation of the pesticide, carbofuran. Electrocatalysis was evidenced from enhanced current signal and less positive oxidation potential of the pesticide on each film, relative to that observed on the bare gold electrode. Mechanism of electrocatalytic oxidation of the pesticide was studied using rotating disc electrode voltammetry.

  4. Iron variation within a granitic pluton as determined by near-infrared reflectance

    Science.gov (United States)

    Baird, A. K.

    1984-01-01

    One-hundred fifty-one previously chemically analyzed samples of tonalite from the Lakeview Mountains pluton, southern California batholith, were analyzed for their iron content using near-infrared spectrophotometry. Compared to the earlier analyses of the same sample set by X-ray fluorescence spectrography, the infrared data have higher analytical variance but clearly define patterns of compositional zonation in the pluton which are closely similar to those patterns obtained from X-ray data; petrogenetic interpretations for the pluton would be the same from either data set. Infrared spectral data can be obtained directly in the field with relatively simple instruments and field measurements can be made to average local heterogeneities that often mask significant plutonic variations.

  5. Application of electrochemical plasma techniques in surface engineering of iron based structural materials

    International Nuclear Information System (INIS)

    Coaca, E.; Rusu, O.; Mihalache, M.; Minca, M.; Tacica, M.; Florea, S.; Oncioiu, G.; Andrei, V.

    2013-01-01

    The surface of austenitic stainless steels 304 L and 316 L was modified by various complex surface treatments: - plasma electrolytic carbo-nitriding by means of Plasma electrolytic saturation (PES); the saturation of cathodic surfaces with C, N was performed using suitable electrolytes (aqueous solutions of inorganic acids, appropriate salts containing the desired elements and certain organic compounds); -electrodeposition of Al from ChCl based Ionic Liquid. The coatings obtained in various experimental conditions have been investigated by means of electron spectroscopy, scanning electron microscopy, energy dispersion x-ray spectrometry, electrochemical techniques, and the properties of the thin films have been correlated with the microstructure and the composition of the surface layers which are strongly dependents of the different regimes of diffusion treatments. The preliminary results on Electrochemical Plasma Technology (EPT) treatments demonstrate that we can select the processing parameters for essential improvement of corrosion behaviour in some aggressive medium and high values of microhardness. (authors)

  6. Field experiment for determining lead accumulation in rice grains of different genotypes and correlation with iron oxides deposited on rhizosphere soil.

    Science.gov (United States)

    Lai, Yu-Cheng; Syu, Chien-Hui; Wang, Pin-Jie; Lee, Dar-Yuan; Fan, Chihhao; Juang, Kai-Wei

    2018-01-01

    Paddy rice (Oryza sativa L.) is a major staple crop in Asia. However, heavy metal accumulation in paddy soil poses a health risk for rice consumption. Although plant uptake of Pb is usually low, Pb concentrations in rice plants have been increasing with Pb contamination in paddy fields. It is known that iron oxide deposits in the rhizosphere influence the absorption of soil Pb by rice plants. In this study, 14 rice cultivars bred in Taiwan, including ten japonica cultivars (HL21, KH145, TC192, TK9, TK14, TK16, TN11, TNG71, TNG84, and TY3) and four indica cultivars (TCS10, TCS17, TCSW2, and TNGS22), were used in a field experiment. We investigated the genotypic variation in rice plant Pb in relation to iron oxides deposited in the rhizosphere, as seen in a suspiciously contaminated site in central Taiwan. The results showed that the cultivars TCSW2, TN11, TNG71, and TNG84 accumulated brown rice Pb exceeding the tolerable level of 0.2mgkg -1 . In contrast, the cultivars TNGS22, TK9, TK14, and TY3 accumulated much lower brown rice Pb (iron oxides deposited on the rhizosphere soil show stronger affinity to soil-available Pb than those on the root surface to form iron plaque. The relative tendency of Pb sequestration toward rhizosphere soil was negatively correlated with the Pb concentrations in brown rice. The iron oxides deposited on the rhizosphere soil but not on the root surface to form iron plaque dominate Pb sequestration in the rhizosphere. Therefore, the enhancement of iron oxide deposits on the rhizosphere soil could serve as a barrier preventing soil Pb on the root surface and result in reduced Pb accumulation in brown rice. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Characterisation and surface reactions of iron oxides and fluorapatite in aqueous suspensions

    OpenAIRE

    Jarlbring, Mathias

    2004-01-01

    The final objective of this study is to produce chemical models of flotation- like systems, including oxidation products of magnetite (maghemite and hematite) together with apatite. This is started by investigating the acid base properties, surface complexation and surface characteristics of the systems hematite-H+ and maghemite-H+ (paper I), fluorapatite-OH- (paper II) and a mixed system of maghemite-fluorapatite-OH- (paper III). Synthetic minerals were prepared and characterised with BET, S...

  8. Validation of a continuous flow method for the determination of soluble iron in atmospheric dust and volcanic ash.

    Science.gov (United States)

    Simonella, Lucio E; Gaiero, Diego M; Palomeque, Miriam E

    2014-10-01

    Iron is an essential micronutrient for phytoplankton growth and is supplied to the remote areas of the ocean mainly through atmospheric dust/ash. The amount of soluble Fe in dust/ash is a major source of uncertainty in modeling-Fe dissolution and deposition to the surface ocean. Currently in the literature, there exist almost as many different methods to estimate fractional solubility as researchers in the field, making it difficult to compare results between research groups. Also, an important constraint to evaluate Fe solubility in atmospheric dust is the limited mass of sample which is usually only available in micrograms to milligrams amounts. A continuous flow (CF) method that can be run with low mass of sediments (solubility studies on dust/ash. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Blocked-micropores, surface functionalized, bio-compatible and silica-coated iron oxide nanocomposites as advanced MRI contrast agent

    International Nuclear Information System (INIS)

    Darbandi, Masih; Laurent, Sophie; Busch, Martin; Li Zian; Yuan Ying; Krüger, Michael; Farle, Michael; Winterer, Markus; Vander Elst, Luce; Muller, Robert N.; Wende, Heiko

    2013-01-01

    Biocompatible magnetic nanoparticles have been found promising in several biomedical applications for tagging, imaging, sensing and separation in recent years. In this article, a systematic study of the design and development of surface-modification schemes for silica-coated iron oxide nanoparticles (IONP) via a one-pot, in situ method at room temperature is presented. Silica-coated IONP were prepared in a water-in-oil microemulsion, and subsequently the surface was modified via addition of organosilane reagents to the microemulsion system. The structure and the morphology of the as synthesized nanoparticles have been investigated by means of transmission electron microscopy (TEM) and measurement of N 2 adsorption–desorption. Electron diffraction and high-resolution transmission electron microscopic (TEM) images of the nanoparticles showed the highly crystalline nature of the IONP structures. Nitrogen adsorption indicates microporous and blocked-microporous structures for the silica-coated and amine functionalized silica-coated IONP, respectively which could prove less cytotoxicity of the functionalized final product. Besides, the colloidal stability of the final product and the presence of the modified functional groups on top of surface layer have been proven by zeta-potential measurements. Owing to the benefit from the inner IONP core and the hydrophilic silica shell, the as-synthesized nanocomposites were exploited as an MRI contrast enhancement agent. Relaxometric results prove that the surface functionalized IONP have also signal enhancement properties. These surface functionalized nanocomposites are not only potential candidates for highly efficient contrast agents for MRI, but could also be used as ultrasensitive biological-magnetic labels, because they are in nanoscale size, having magnetic properties, blocked-microporous and are well dispersible in biological environment.

  10. Determinants of quality of life of patients with heart failure and iron deficiency treated with ferric carboxymaltose: FAIR-HF sub-analysis.

    Science.gov (United States)

    Gutzwiller, Florian S; Pfeil, Alena M; Comin-Colet, Josep; Ponikowski, Piotr; Filippatos, Gerasimos; Mori, Claudio; Braunhofer, Peter G; Szucs, Thomas D; Schwenkglenks, Matthias; Anker, Stefan D

    2013-10-09

    Heart failure (HF) is a burden to patients and health care systems. The objectives of HF treatment are to improve health related quality of life (HRQoL) and reduce mortality and morbidity. We aimed to evaluate determinants of health-related quality of life (HRQoL) in patients with iron deficiency and HF treated with intravenous (i.v.) iron substitution or placebo. A randomised, double-blind, placebo-controlled trial (n = 459) in iron-deficient chronic heart failure (CHF) patients with or without anaemia studied clinical and HRQoL benefits of i.v. iron substitution using ferric carboxymaltose (FCM) over a 24-week trial period. Multivariate analysis was carried out with various clinical variables as independent variables and HRQoL measures as dependent variables. Mean change from baseline of European Quality of Life - 5 Dimensions (EQ-5D) (value set-based) utilities (on a 0 to 100 scale) at week 24 was 8.91 (i.v. iron) and 0.68 (placebo; p model remained stable. In this study, i.v. iron substitution, exercise tolerance, stroke, country of residence and renal function influenced measures of HRQoL in patients with heart failure and iron deficiency. © 2013.

  11. Method of simultaneous continuous determination of transfer rates of iron and chromium into solution during Fe-Cr alloys dissolution

    International Nuclear Information System (INIS)

    Shirinov, T.I.; Florianovich, G.M.; Skuratnik, Ya.B.

    1978-01-01

    Radiometry method of simultaneous continuous registration of transfer rates of iron and chromium into solution from Fe-Cr alloys with various composition has been developed. Using gamma-spectrometer components of Fe-Cr alloys can be determined with high sensitivity in separate samples according to Fe 59 and Cr 51 radioactive labels, obtained by neutron activation. The above method is applied to estimate Fe and Cr transfer rates into H 2 SO 4 solution at the temperature of 50 deg from Fe - 28% Cr alloy during its active dissolution. It is established, that beginning with some seconds of alloy and solution contact, its components transfer into the solution in the same composition, as in the alloy. The method enables to determine Fe with the accuracy of up to 5% and Cr with that of up to 10%

  12. Determination of the diffusion coefficients of iron and chromium in Pb17Li at 500 deg C

    International Nuclear Information System (INIS)

    Simon, N.; Flament, T.; Terlain, A.

    1992-01-01

    The diffusion of the dissolved metallic species in a liquid metal towards the boundary layer is one of the elementary steps of the overall mass transfer process induced by thermal gradient. This phenomenon is very probably the limiting step in the mass transfer of martensitic Fe-Cr steels in the presence of Pb17Li liquid eutectic alloy. For estimating diffusion flux, the diffusion coefficients of iron and chromium in Pb17Li are needed but are not known. Consequently these data have been determined in CEA laboratory by measuring metal loss of cylindrical specimens after rotation at 500 deg C in Pb17Li for several hours and applying the first Fick diffusion law in the boundary layer whose the thickness has been previously determined by EISENBERG. After a description of the experimental device, the results are presented and discussed

  13. Determination of copper, iron and zinc in spirituous beverages by total reflection X-ray fluorescence spectrometry

    Science.gov (United States)

    Capote, T.; Marcó, L. M.; Alvarado, J.; Greaves, E. D.

    1999-10-01

    The concentration of copper in traditional homemade alcoholic distillates produced in Venezuela (Cocuy de Penca) were determined by total reflection X-ray fluorescence (TXRF) using vanadium as internal standard. The results were compared to those obtained by flame atomic absorption spectrometry (FAAS). Three preparative methods of addition of vanadium were compared: classical internal standard addition, 'layer on layer' internal standard addition and in situ addition of internal standard. The TXRF procedures were accurate and the precision was comparable to that obtained by the FAAS technique. Copper levels were above the maximum allowed limits for similar beverages. Zinc and iron in commercial and homemade distilled beverages were also analyzed by TXRF with in situ addition of internal standard demonstrating the usefulness of this technique for trace metal determination in distillates.

  14. Oxidation of a Dimethoxyhydroquinone by Ferrihydrite and Goethite Nanoparticles: Iron Reduction versus Surface Catalysis.

    Science.gov (United States)

    Krumina, Lelde; Lyngsie, Gry; Tunlid, Anders; Persson, Per

    2017-08-15

    Hydroquinones are important mediators of electron transfer reactions in soils with a capability to reduce Fe(III) minerals and molecular oxygen, and thereby generating Fenton chemistry reagents. This study focused on 2,6-dimethoxy hydroquinone (2,6-DMHQ), an analogue to a common fungal metabolite, and its reaction with ferrihydrite and goethite under variable pH and oxygen concentrations. Combined wet-chemical and spectroscopic analyses showed that both minerals effectively oxidized 2,6-DMHQ in the presence of oxygen. Under anaerobic conditions the first-order oxidation rate constants decreased by one to several orders of magnitude depending on pH and mineral. Comparison between aerobic and anaerobic results showed that ferrihydrite promoted 2,6-DMHQ oxidation both via reductive dissolution and heterogeneous catalysis while goethite mainly caused catalytic oxidation. These results were in agreement with changes in the reduction potential (E H ) of the Fe(III) oxide/Fe(II) aq redox couple as a function of dissolved Fe(II) where E H of goethite was lower than ferrihydrite at any given Fe(II) concentration, which makes ferrihydrite more prone to reductive dissolution by the 2,6-DMBQ/2,6-DMHQ redox couple. This study showed that reactions between hydroquinones and iron oxides could produce favorable conditions for formation of reactive oxygen species, which are required for nonenzymatic Fenton-based decomposition of soil organic matter.

  15. Fob1 and Fob2 proteins are virulence determinants of Rhizopus oryzae via facilitating iron uptake from ferrioxamine

    Science.gov (United States)

    Dialysis patients with chronic renal failure receiving deferoxamine for treating iron overload are uniquely predisposed for mucormycosis. Although not secreted by Mucorales, previous studies established that Rhizopus species utilize iron from ferrioxamine (iron-rich form of deferoxamine). Here we de...

  16. Surface anisotropy of iron oxide nanoparticles and slabs from first principles: Influence of coatings and ligands as a test of the Heisenberg model

    Energy Technology Data Exchange (ETDEWEB)

    Brymora, Katarzyna; Calvayrac, Florent, E-mail: Florent.Calvayrac@univ-lemans.fr

    2017-07-15

    Highlights: • A new method is given to extract surface anisotropies from ab initio calculations. • Heisenberg model for magnetic clusters and surfaces is validated in simple cases. • Ligands, metallic clusters, or coatings degrade the validity of the Heisenberg model. • Values for surface anisotropies, volume anisotropies, exchange constants are computed. • Results are in agreement with experimental data, previous theoretical findings. - Abstract: We performed ab initio computations of the magnetic properties of simple iron oxide clusters and slabs. We considered an iron oxide cluster functionalized by a molecule or glued to a gold cluster of the same size. We also considered a magnetite slab coated by cobalt oxide or a mixture of iron oxide and cobalt oxide. The changes in magnetic behavior were explored using constrained magnetic calculations. A possible value for the surface anisotropy was estimated from the fit of a classical Heisenberg model on ab initio results. The value was found to be compatible with estimations obtained by other means, or inferred from experimental results. The addition of a ligand, coating, or of a metallic nanoparticle to the systems degraded the quality of the description by the Heisenberg Hamiltonian. Proposing a change in the anisotropies allowing for the proportion of each transition atom we could get a much better description of the magnetism of series of hybrid cobalt and iron oxide systems.

  17. What happens when iron becomes wet? Observation of reactions at interfaces between liquid and metal surfaces

    CERN Document Server

    Kimura, M

    2003-01-01

    Synchrotron-radiation has been applied to investigation of interfaces between liquid and metal surfaces, with a special attention to corrosion. Three topics are shown: (1) nano structures of rusts formed on steel after atmospheric corrosion. Evolution of 'Fe(O, OH) sub 6 network' is the key to understand how the durable rusts prevent from formation of more rusts. (2) In situ observation of reactions at the interface has been carried out for localized corrosion of stainless steel. It is shown that change in states of Cr sup 3 sup + and Br sup - ions near the interface is deeply related with a breakout of the passivation film. (3) A structural phase transformation on a Cu sub 3 Au(001) surface was investigated. Ordering remains even at a temperature higher than the bulk-critical temperature, showing surface-induced ordering. These approaches gives us crucial information for a new steel-product. (author)

  18. A precise determination of the nucleon structure functions in charged-current interactions on an iron target

    International Nuclear Information System (INIS)

    Vallage, B.

    1987-01-01

    570 000 neutrino-iron and 370 000 antineutrino-iron charged-current events were obtained from the Wide Band Beam exposure of the CDHS detector at CERN in 1983, at energies ranging from 20 to 400 GeV. These large statistics allowed a precise measurement of the charged-current differential cross-sections and a detailed study of systematic effects. The nucleon structure functions have been determined in the framework of the quark-parton model, in the kinematic range: 0.015 2 2 /c 2 . The longitudinal structure function F L (x) is in good agreement with the QCD predicted shape. Deviations from scale invariance are clearly seen from the functions F 2 and xF 3 . The Q 2 evolution of the valence quark distribution has been compared with the QCD prediction in order to measure the scale parameter Λ. A good agreement is obtained only if the low Q 2 points are removed from the comparison. Our experiment favours a value of Λ between 50 and 250 MeV [fr

  19. Synthesis of nitrogen- and iron-containing carbon dots, and their application to colorimetric and fluorometric determination of dopamine

    International Nuclear Information System (INIS)

    Wang, Bin; Chen, Yanfen; Wu, Yuanya; Weng, Bo; Liu, Yingshuai; Li, Chang Ming

    2016-01-01

    Nitrogen- and iron-containing carbon dots (N,Fe-CDs) are synthesized by hydrothermal treatment of branched polyethylenimine (BPEI) and hemin at 180 °C. The N,Fe-CDs are mainly doped with nitrogen and trace amounts of iron(III). The N,Fe-CDs also display intrinsic fluorescence with excitation/emission maxima at 365/452 nm and a quantum yield of 27 %. The nanodots are shown to act as peroxidase mimics by catalyzing the oxidation of tetramethylbenzidine (TMB) by hydrogen peroxide to form a blue product whose quantity can be determined by photometry at 652 nm. This was exploited to design colorimetric and fluorometric assays for dopamine (DA). The colorimetric assay is based on the oxidation of DA by H2O2 in presence of the N,Fe-CDs and TMB. It has an instrumental detection limit of 40 nM (at an S/N ratio of 3), and a visual detection limit of 0.4 μM. The fluorometric assay is based on an inner filter effect that is caused by the formation of oxidized TMB which overlaps (and absorbs) the emission of the N,Fe-CDs located at 452 nm. The fluorometric detection limit is as low as 20 nM (at an S/N ratio of 3). (author)

  20. Biogeochemistry of sulfur and iron in Thioploca-colonized surface sediments in the upwelling area off central chile

    Science.gov (United States)

    Zopfi, Jakob; Böttcher, Michael E.; Jørgensen, Bo Barker

    2008-02-01

    The biogeochemistry of sedimentary sulfur was investigated on the continental shelf off central Chile at water depths between 24 and 88 m under partial influence of an oxygen minimum zone. Dissolved and solid iron and sulfur species, including the sulfur intermediates sulfite, thiosulfate, and elemental sulfur, were analyzed at high resolution in the top 20 cm. All stations were characterized by high rates of sulfate reduction, but only the sediments within the Bay of Concepción contained dissolved sulfide. Due to advection and/or in-situ reoxidation of sulfide, dissolved sulfate was close to bottom water values. Whereas the concentrations of sulfite and thiosulfate were mostly in the submicromolar range, elemental sulfur was by far the dominant sulfur intermediate. Although the large nitrate- and sulfur-storing bacteria Thioploca were abundant, the major part of S 0 was located extracellularly. The distribution of sulfur species and dissolved iron suggests the reaction of sulfide with FeOOH as an important pathway for sulfide oxidation and sulfur intermediate formation. This is in agreement with the sulfur isotope composition of co-existing elemental sulfur and iron monosulfides. In the Bay of Concepción, sulfur isotope data suggest that pyrite formation proceeds via the reaction of FeS with polysulfides or H 2S. At the shelf stations, on the other hand, pyrite was significantly depleted in 34S relative to its potential precursors FeS and S 0. Isotope mass balance considerations suggest further that pyritization at depth includes light sulfide, potentially originating from bacterial sulfur disproportionation. The δ 34S-values of pyrite down to -38‰ vs. V-CDT are among the lightest found in organic-rich marine sediments. Seasonal variations in the sulfur isotope composition of dissolved sulfate indicated a dynamic non-steady-state sulfur cycle in the surface sediments. The 18O content of porewater sulfate increased with depth at all sites compared to the

  1. Influence of magnetic anisotropy on dynamic magnonic crystals created by surface acoustic waves in yttrium iron garnet films

    Energy Technology Data Exchange (ETDEWEB)

    Kryshtal, R.G.; Medved, A.V., E-mail: avm@ms.ire.rssi.ru

    2017-03-15

    Experimental results on the investigation of the influence of magnetic crystallographic anisotropy onto parameters of dynamic magnonic crystals arising at surface acoustic wave (SAW) propagation in yttrium iron garnet (YIG) films are presented. The main features of such an influence, as we have shown, are: 1) appearance of extra magnonic band gaps together with the normal magnonic band gap existing without anisotropy, 2) the absence of reflections of the incident surface magnetostatic wave at the frequency of these extra gaps, 3) the same depth for the extra gaps was achieved with a relatively small SAW power, almost by the order of magnitude less than in the case of normal magnonic gaps caused by SAW. A possible explanation of the features is given on the base of inelastic scattering of surface magnetostatic waves by SAW with the transformation of the reflected surface wave to the anisotropic direct volume magnetostatic wave existence of which is due to cubic crystallographic anisotropy in YIG. These results may be useful in designing new devices of information processing. - Highlights: • A new mechanism of creation of dynamic magnonic crystals by SAW propagating in real YIG films with magnetic anisotropy is investigated. • This mechanism is based on inelastic scattering of SMSW by SAW with SMSW transformation to the anisotropic volume magnetostatic wave. • This mechanism brings to creating by SAW additional (extra) magnonic stop bands for SMSW. • The given depth of these band gaps is achieved at SAW powers of the order of magnitude less than in the case of normal magnonic gaps created by SAW in the magnonic crystal without taking into account the anisotropy. • No reflected waves, usually taking place at SMSW propagation at the frequency of normal magnonic gaps, were detected. Such extra gaps look like a magnonic 'black hole' for SMSW. • These new properties of SAW-magnonic crystals, given by the magnetic anisotropy, may be used at creating

  2. Influence of magnetic anisotropy on dynamic magnonic crystals created by surface acoustic waves in yttrium iron garnet films

    International Nuclear Information System (INIS)

    Kryshtal, R.G.; Medved, A.V.

    2017-01-01

    Experimental results on the investigation of the influence of magnetic crystallographic anisotropy onto parameters of dynamic magnonic crystals arising at surface acoustic wave (SAW) propagation in yttrium iron garnet (YIG) films are presented. The main features of such an influence, as we have shown, are: 1) appearance of extra magnonic band gaps together with the normal magnonic band gap existing without anisotropy, 2) the absence of reflections of the incident surface magnetostatic wave at the frequency of these extra gaps, 3) the same depth for the extra gaps was achieved with a relatively small SAW power, almost by the order of magnitude less than in the case of normal magnonic gaps caused by SAW. A possible explanation of the features is given on the base of inelastic scattering of surface magnetostatic waves by SAW with the transformation of the reflected surface wave to the anisotropic direct volume magnetostatic wave existence of which is due to cubic crystallographic anisotropy in YIG. These results may be useful in designing new devices of information processing. - Highlights: • A new mechanism of creation of dynamic magnonic crystals by SAW propagating in real YIG films with magnetic anisotropy is investigated. • This mechanism is based on inelastic scattering of SMSW by SAW with SMSW transformation to the anisotropic volume magnetostatic wave. • This mechanism brings to creating by SAW additional (extra) magnonic stop bands for SMSW. • The given depth of these band gaps is achieved at SAW powers of the order of magnitude less than in the case of normal magnonic gaps created by SAW in the magnonic crystal without taking into account the anisotropy. • No reflected waves, usually taking place at SMSW propagation at the frequency of normal magnonic gaps, were detected. Such extra gaps look like a magnonic 'black hole' for SMSW. • These new properties of SAW-magnonic crystals, given by the magnetic anisotropy, may be used at creating

  3. Surface Functionalization of Epoxy-Resist- Based Microcantilevers with Iron Oxide Nanocrystals

    DEFF Research Database (Denmark)

    Ingrosso, Chiara; Sardella, E.; Keller, Stephan Sylvest

    2010-01-01

    A functionalization procedure is integrated in the fabrication of micromechanical SU-8 cantilevers in order to chemically bind organic-capped Fe2O3 NCs at the photoresist surface, under visible light, ambient atmosp here and room temperature. The achieved highly interconnected NC multilayer netwo...... is demonstrated an active layer for real-time detection of acetone vapor molecules....

  4. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water

    NARCIS (Netherlands)

    Van Der Grift, B.; Rozemeijer, J. C.; Griffioen, J.; Van Der Velde, Y.

    2014-01-01

    The retention of phosphorus in surface waters through co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from

  5. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water.

    NARCIS (Netherlands)

    Grift, van der B.; Rozemeijer, J.C.; Griffioen, J.; Velde, van der Y.

    2014-01-01

    The retention of phosphorus in surface waters though co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and 5 P immobilization along the flow-path

  6. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water

    NARCIS (Netherlands)

    van der Grift, B.; Rozemeijer, J. C.; Griffioen, J.; van der Velde, Y.

    2014-01-01

    The retention of phosphorus in surface waters though co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from

  7. Iron geochemistry and organic carbon preservation by iron (oxyhydr)oxides in surface sediments of the East China Sea and the south Yellow Sea

    Science.gov (United States)

    Ma, Wei-Wei; Zhu, Mao-Xu; Yang, Gui-Peng; Li, Tie

    2018-02-01

    In marine sediments factors that influence iron (Fe) geochemistry and its interactions with other elements are diverse and remain poorly understood. Here we comparatively study Fe speciation and reactive Fe-bound organic carbon (Fe-OC) in surface sediments of the East China Sea (ECS) and the south Yellow Sea (SYS). The objectives are to better understand the potential impacts of geochemically distinct sediment sources and depositional/diagenetic settings on Fe geochemistry and OC preservation by Fe (hydr)oxides in sediments of the two extensive shelf seas around the world. Contents of carbonate- and acid-volatile-sulfide (AVS)-associated Fe(II) (FeAVS + carb) and magnetite (Femag) in the ECS sediments are about 5 and 9 times higher, respectively, than in the SYS. This could be ascribed to the ferruginous conditions of the ECS sediments that favor the formation/accumulation of Fecarb and Femag, a unique feature of marine unsteady depositional regimes. Much lower total Fe(II) contents in the SYS than in the ECS suggest that lower availability of highly reactive Fe (FeHR) and/or weak Fe reduction is a factor limiting Fe(II) formation and accumulation in the SYS sediments. The ratio of FeHR to total Fe is, on average, markedly higher (2.4 times) in the ECS sediments than in the SYS, which may be a combined result of several factors relevant to different sediment sources and depositional/diagenetic settings. In comparison with many other marine sediments, the percent fractions (fFe-OC) of Fe-OC to total organic carbon (TOC) in the ECS and the SYS are low, which can be ascribed to surface adsorption of OC rather than coprecipitation or organic complexation as the dominant binding mechanisms. Based on the fFe-OC in this study, total Fe-OC estimated for global continental shelves is equivalent to 38% of the atmospheric CO2 pool, which indicates the important role of sorptive stabilization of Fe-OC in continental shelf sediments for buffering CO2 release to the atmosphere

  8. Effects of iron-reducing bacteria and nitrate-reducing bacteria on the transformations of iron corrosion products, magnetite and siderite, formed at the surface of non-alloy steel

    International Nuclear Information System (INIS)

    Etique, Marjorie

    2014-01-01

    Radioactive waste is one of the major problems facing the nuclear industry. To circumvent this issue France plans to store vitrified high-level nuclear waste in a stainless steel container, placed into a non-alloy steel overpack, at a depth of 500 m in an argillaceous formation. The main iron corrosion products formed at the surface of the non-alloy steel are siderite (Fe II CO 3 ) and magnetite (Fe II Fe III 2 O 4 ). These compounds are formed in the anoxic conditions present in the nuclear waste repository and play a protective role against corrosion as a passive layer. This work aims to investigate the activity of nitrate-reducing bacteria (NRB, Klebsiella mobilis) and iron-reducing bacteria (IRB, Shewanella putrefaciens) during the transformation of siderite and magnetite, especially those involved in anoxic iron biogeochemical cycle. Klebsiella mobilis and Shewanella putrefaciens were first incubated with siderite or magnetite suspensions (high surface specific area) in order to exacerbate the microbial iron transformation, subsequently incubated with a magnetite/siderite film synthesized by anodic polarization at applied current density. The transformation of siderite and magnetite by direct or indirect microbial processes led to the formation of carbonated green rust (Fe II 4 Fe III 2 (OH) 12 CO 3 ). As a transient phase shared by several bacterial reactions involving Fe II and Fe III , this compound is the cornerstone of the anoxic iron biogeochemical cycle. The novelty of this thesis is the consideration of bacterial metabolisms of NRB and IRB often overlooked in bio-corrosion processes. (author) [fr

  9. Effects of Iron-Oxide Nanoparticle Surface Chemistry on Uptake Kinetics and Cytotoxicity in CHO-K1 Cells

    Directory of Open Access Journals (Sweden)

    Camille C. Hanot

    2015-12-01

    Full Text Available Superparamagnetic iron-oxide nanoparticles (SPIONs show great promise for multiple applications in biomedicine. While a number of studies have examined their safety profile, the toxicity of these particles on reproductive organs remains uncertain. The goal of this study was to evaluate the cytotoxicity of starch-coated, aminated, and PEGylated SPIONs on a cell line derived from Chinese Hamster ovaries (CHO-K1 cells. We evaluated the effect of particle diameter (50 and 100 nm and polyethylene glycol (PEG chain length (2k, 5k and 20k Da on the cytotoxicity of SPIONs by investigating cell viability using the tetrazolium dye 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT and sulforhodamine B (SRB assays. The kinetics and extent of SPION uptake by CHO-K1 cells was also studied, as well as the resulting generation of intracellular reactive oxygen species (ROS. Cell toxicity profiles of SPIONs correlated strongly with their cellular uptake kinetics, which was strongly dependent on surface properties of the particles. PEGylation caused a decrease in both uptake and cytotoxicity compared to aminated SPIONs. Interestingly, 2k Da PEG-modifed SPIONs displayed the lowest cellular uptake and cytotoxicity among all studied particles. These results emphasize the importance of surface coatings when engineering nanoparticles for biomedical applications.

  10. Nonreciprocity of spin waves in magnonic crystals created by surface acoustic waves in structures with yttrium iron garnet

    International Nuclear Information System (INIS)

    Kryshtal, R.G.; Medved, A.V.

    2015-01-01

    Experimental results of investigations of nonreciprocity for surface magnetostatic spin waves (SMSW) in the magnonic crystal created by surface acoustic waves (SAW) in yttrium iron garnet films on a gallium gadolinium garnet substrate as without metallization and with aluminum films with different electrical conductivities (thicknesses) are presented. In structures without metallization, the frequency of magnonic gaps is dependent on mutual directions of propagation of the SAW and SMSW, showing nonreciprocal properties for SMSW in SAW – magnonic crystals even with the symmetrical dispersion characteristic. In metalized SAW – magnonic crystals the shift of the magnonic band gaps frequencies at the inversion of the biasing magnetic field was observed. The frequencies of magnonic band gaps as functions of SAW frequency are presented. Measured dependencies, showing the decrease of magnonic gaps frequency and the expansion of the magnonic band gap width with the decreasing of the metal film conductivity are given. Such nonreciprocal properties of the SAW – magnonic crystals are promising for signal processing in the GHz range. - Highlights: • Spin waves nonreciprocity in YIG magnonic crystals with SAW was studied. • SAW was shown to create nonreciprocity for spin waves in YIG–GGG even without metal. • Frequency and width of magnonic band gaps were measured versus metal conductivity. • Conductivity for practical use of spin waves in the structure YIG–metal was defined

  11. Contribution of coated humic acids calculated through their surface coverage on nano iron oxides for ofloxacin and norfloxacin sorption.

    Science.gov (United States)

    Peng, Hongbo; Liang, Ni; Li, Hao; Chen, Fangyuan; Zhang, Di; Pan, Bo; Xing, Baoshan

    2015-09-01

    Sorption of organic contaminants on organo-mineral complexes has been investigated extensively, but the sorption contribution of mineral particles was not properly addressed before calculating KOC, especially for ionic organic contaminants. We measured the surface coverage of a humic acid (HA) on nano iron oxides (n-Fe2O3) in a series of synthesized organo-mineral complexes. The contribution of the coated HA to ofloxacin (OFL) and norfloxacin (NOR) sorption in HA-n-Fe2O3 complexes was over 80% of the total sorption with the surface coverage of 36% and fOC of 1.6%. All the coated HA showed higher sorption to NOR and OFL in comparison to the original HA, suggesting HA fractionation and/or physical re-conformation during organo-mineral complex formation. The decreased KOC with multilayer coating may suggest the importance of site-specific interactions for OFL sorption, while the increased KOC with multilayer coating may suggest the importance of partitioning in hydrophobic region for NOR sorption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Nonreciprocity of spin waves in magnonic crystals created by surface acoustic waves in structures with yttrium iron garnet

    Energy Technology Data Exchange (ETDEWEB)

    Kryshtal, R.G.; Medved, A.V., E-mail: avm@ms.ire.rssi.ru

    2015-12-01

    Experimental results of investigations of nonreciprocity for surface magnetostatic spin waves (SMSW) in the magnonic crystal created by surface acoustic waves (SAW) in yttrium iron garnet films on a gallium gadolinium garnet substrate as without metallization and with aluminum films with different electrical conductivities (thicknesses) are presented. In structures without metallization, the frequency of magnonic gaps is dependent on mutual directions of propagation of the SAW and SMSW, showing nonreciprocal properties for SMSW in SAW – magnonic crystals even with the symmetrical dispersion characteristic. In metalized SAW – magnonic crystals the shift of the magnonic band gaps frequencies at the inversion of the biasing magnetic field was observed. The frequencies of magnonic band gaps as functions of SAW frequency are presented. Measured dependencies, showing the decrease of magnonic gaps frequency and the expansion of the magnonic band gap width with the decreasing of the metal film conductivity are given. Such nonreciprocal properties of the SAW – magnonic crystals are promising for signal processing in the GHz range. - Highlights: • Spin waves nonreciprocity in YIG magnonic crystals with SAW was studied. • SAW was shown to create nonreciprocity for spin waves in YIG–GGG even without metal. • Frequency and width of magnonic band gaps were measured versus metal conductivity. • Conductivity for practical use of spin waves in the structure YIG–metal was defined.

  13. Determination of trace amounts of lead, arsenic, nickel and cobalt in high-purity iron oxide pigment by inductively coupled plasma atomic emission spectrometry after iron matrix removal with extractant-contained resin

    International Nuclear Information System (INIS)

    Xu Yuyu; Zhou Jianfeng; Wang Guoxin; Zhou Jinfan; Tao Guanhong

    2007-01-01

    Inductively coupled plasma atomic emission spectrometry (ICP-AES) was applied to the determination of lead, arsenic, nickel and cobalt in high-purity iron oxide pigment. Samples were dissolved with hydrochloric acid and hydrogen peroxide. The digest was passed through a column, which was packed with a polymer resin containing a neutral organophosphorus extractant, tri-n-butylphosphate. Iron was sorbed selectively on the resin and the analytes of interest passed through the column, allowing the effective separation of them from the iron matrix. Conditions of separation were optimized. The detection limits (3σ) in solution were 10, 40, 7 and 5 μg L -1 , and in pigment were 0.2, 0.8, 0.14 and 0.1 mg kg -1 for lead, arsenic, cobalt and nickel, respectively. The recoveries ranged from 95% to 107% when sample digests were spiked with 5 μg of the analytes of interest, and relative standard deviations (n = 6) were 1.5-17.6% for the determination of the spiked samples. The method was successfully applied to the determination of trace amounts of these elements in high-purity iron oxide pigment samples

  14. A pre-concentration procedure using coprecipitation for determination of lead and iron in several samples using flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Saracoglu, S.; Soylak, M.; Peker, D.S. Kacar; Elci, L.; Santos, W.N.L. dos; Lemos, V.A.; Ferreira, S.L.C.

    2006-01-01

    The present paper proposes a pre-concentration procedure for determination of lead and iron in several samples by flame atomic absorption spectrometry. In it, lead(II) and iron(III) ions are coprecipitated using the violuric acid-copper(II) system as collector. Afterwards, the precipitate is dissolved with 1 M HNO 3 solution and the metal ions are determined. The optimization step was performed using factorial design involving the variables: pH, violuric acid mass (VA) and copper concentration (Cu). Using the optimized experimental conditions, the proposed procedure allows the determination these metals with detection limits of 0.18 μg L -1 for iron and 0.16 μg L -1 for lead. The effects of foreign ions on the pre-concentration procedure were also evaluated and the results demonstrated that this method could be applied for determination of iron and lead in several real samples. The proposed method was successfully applied to the analysis of seawater, urine, mineral water, soil and physiological solution samples. The concentrations of lead and iron achieved in these samples agree well with others data reported in the literature

  15. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water

    Science.gov (United States)

    van der Grift, B.; Rozemeijer, J. C.; Griffioen, J.; van der Velde, Y.

    2014-11-01

    The retention of phosphorus in surface waters through co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from groundwater into surface water in an agricultural experimental catchment of a small lowland river. We physically separated tube drain effluent from groundwater discharge before it entered a ditch in an agricultural field. Through continuous discharge measurements and weekly water quality sampling of groundwater, tube drain water, exfiltrated groundwater, and surface water, we investigated Fe(II) oxidation kinetics and P immobilization processes. The oxidation rate inferred from our field measurements closely agreed with the general rate law for abiotic oxidation of Fe(II) by O2. Seasonal changes in climatic conditions affected the Fe(II) oxidation process. Lower pH and lower temperatures in winter (compared to summer) resulted in low Fe oxidation rates. After exfiltration to the surface water, it took a couple of days to more than a week before complete oxidation of Fe(II) is reached. In summer time, Fe oxidation rates were much higher. The Fe concentrations in the exfiltrated groundwater were low, indicating that dissolved Fe(II) is completely oxidized prior to inflow into a ditch. While the Fe oxidation rates reduce drastically from summer to winter, P concentrations remained high in the groundwater and an order of magnitude lower in the surface water throughout the year. This study shows very fast immobilization of dissolved P during the initial stage of the Fe(II) oxidation process which results in P-depleted water before Fe(II) is completely depleted. This cannot be explained by surface complexation of phosphate to freshly formed Fe-oxyhydroxides but indicates the formation of Fe(III)-phosphate precipitates. The formation of Fe(III)-phosphates at redox gradients

  16. Research on Laser Micro Polishing of SLS Technology Sintered Iron-Based Powder Surface

    OpenAIRE

    Gerda Vaitkūnaitė; Vladislav Markovič; Olegas Černašėjus

    2015-01-01

    The article analyzes laser micro polishing of 1.2083 steel samples produced applying selective laser sintering (SLS) method. The study has evaluated the distribution of the shape, size and temperature of the laser beam treated area in the surface layer of sintered and laser polished samples. Experimental tests have shown the impact of the technical parameters of laser micro polishing on the width and hardness of the impact zone of the treated sample. The microstructure analysis of laser treat...

  17. Preconcentration and atomic absorption spectrometric determination of cadmium, cobalt, copper, iron, lead, manganese, nickel and zinc in water samples using 6-methyl-2-pyridinecarboxaldehyde-4-phenyl-3-thiosemicarbazone

    International Nuclear Information System (INIS)

    Khuhawar, M.Y.; Das, P.; Dewani, V.K.

    2005-01-01

    The reagent 6-methyl-2-pyridinecarboxaldehyde-4-phenyl-3-thiosemicarbazone (MPAPT) has been examined for the pre-concentration of metal ions and determination using air acetylene flame atomic absorption spectrometer. The method is based on the complexation and extraction of cadmium (II), cobalt(III), copper(II), lead(II), nickel(II), iron(II), iron(II), manganese(II) and zinc(II) in chloroform. The metal iron are back extracted in nitric acid (1:1) or after evaporation of solvent the residue is digested in nitric acid. After necessary adjustment of volume the metal ions were determined in aqueous solution. Pre-concentration is obtained 10-25 times. Metal ions recovery was 95.4-100.8% with coefficient of variation 0.2-7.5%. The method used for the determination of metals in canal and sewerage waters, within 2-6433 mu g/L with C. V 0.-5.2%. (author)

  18. Iron phthalocyanine on Cu(111): Coverage-dependent assembly and symmetry breaking, temperature-induced homocoupling, and modification of the adsorbate-surface interaction by annealing.

    Science.gov (United States)

    Snezhkova, Olesia; Bischoff, Felix; He, Yuanqin; Wiengarten, Alissa; Chaudhary, Shilpi; Johansson, Niclas; Schulte, Karina; Knudsen, Jan; Barth, Johannes V; Seufert, Knud; Auwärter, Willi; Schnadt, Joachim

    2016-03-07

    We have examined the geometric and electronic structures of iron phthalocyanine assemblies on a Cu(111) surface at different sub- to mono-layer coverages and the changes induced by thermal annealing at temperatures between 250 and 320 °C by scanning tunneling microscopy, x-ray photoelectron spectroscopy, and x-ray absorption spectroscopy. The symmetry breaking observed in scanning tunneling microscopy images is found to be coverage dependent and to persist upon annealing. Further, we find that annealing to temperatures between 300 and 320 °C leads to both desorption of iron phthalocyanine molecules from the surface and their agglomeration. We see clear evidence of temperature-induced homocoupling reactions of the iron phthalocyanine molecules following dehydrogenation of their isoindole rings, similar to what has been observed for related tetrapyrroles on transition metal surfaces. Finally, spectroscopy indicates a modified substrate-adsorbate interaction upon annealing with a shortened bond distance. This finding could potentially explain a changed reactivity of Cu-supported iron phthalocyanine in comparison to that of the pristine compound.

  19. The desorption of Phosphorous (32 P) fixed on iron and aluminum oxy-hydroxide surfaces by the soil microbial biomass

    International Nuclear Information System (INIS)

    Araujo, Lilian Maria Cesar de.

    1995-02-01

    This work determines whether the soil microbial biomass, with an ample supply of available C, can utilize P adsorber in the surfaces of oxy-hydroxides of Fe or Al of soil-P deficient soils. To simulate the surfaces of the natural Fe and Al compounds, synthetic oxy-hydroxides of Fe and Al, impregnated in strips of filter paper, and containing P tagged with 32 P, were used. (author). 60 refs., 7 figs., 7 tabs

  20. Determination of Iron and Nickel in Geological Samples by Activation Analysis with Reactor Fast Neutrons

    International Nuclear Information System (INIS)

    El Abd, A.

    2009-01-01

    Threshold reactions induced by reactor fast neutrons are well recognized. The concentration of Fe and Ni were determined in nine geological samples by activation analysis with reactor fast neutrons using the threshold reactions 5 4F e( n,p) 54 Mn and 58 Ni ( n, p )'5 8 Co respectively. The fast neutron flux was determined using the reactions 92 Mo(n, 2n) 92 mNb and 95 Mo(n,p) 95 Nb. The determined concentration of Fe and Ni in the samples were checked by determining them in the GSJ JB-1 reference material using the same , ( p, n) reactions. There are a good agreement between the measured and recommended values. The concentrations of Fe were also determined by the ) , ( n, γ) capture reactions in the geological samples and the JB-1 reference material using the K θ - NAA method. There are good agreements between the determined concentrations from the ) , ( p, n) and the ( γ, n) reactions.

  1. Diagnostics of corotating interaction regions with the kinetic properties of iron ions as determined with STEREO/PLASTIC

    Directory of Open Access Journals (Sweden)

    P. Bochsler

    2010-02-01

    Full Text Available STEREO/PLASTIC determines three-dimensional distributions of solar wind iron ions with unprecedented time resolution. Typically 300 to 1000 counts are registered within each 5 min time interval. For the present study we use the information contained in these distributions to characterize CIRs (Corotating Interaction Regions in two test cases. We perform a consistency test for both the derived physical parameters and for the analytical model of CIRs of Lee (2000. At 1 AU we find that apart from compositional changes the most indicative parameter for marking the time when a CIR passes a spacecraft is the angular deflection of the flow vector of particles. Changes in particle densities and the changes in magnitudes of speeds are apparently less reliable indicators of stream interfaces.

  2. Graphic-analytical determination of statics of reduction reextraction of plutonium using iron(2) as a reducing agent

    International Nuclear Information System (INIS)

    Pochinajlo, A.

    1977-01-01

    The grafic technological scheme of reduction reextraction of plutonium has been designed and the experiments on the laboratory 16-staged extractor of a mixer-settler type have been carried. From the concentration profiles found for a steady stage the content of plutonium(4) and plutonium(3) in organic and water phases in every stage is calculated. Then using the equations of material balance and extraction equilibrium a kinetic formula describing the reduction of plutonium(4) by iron(2f.) in a separate stage is deduced. Since the kinetic parameter A has been found to be close for all the staqes the analytical expression has been obtained with the help of which it is possible to determine a priori the plutonium(4) concentration profile in a reextraction part of the extractor for the given technological process conditions characterized by the defenite A. The plutonium(4) concentration profiles for the organic phase with different values A are presented

  3. Shock Melting of Iron Silicide as Determined by In Situ X-ray Diffraction.

    Science.gov (United States)

    Newman, M.; Kraus, R. G.; Wicks, J. K.; Smith, R.; Duffy, T. S.

    2016-12-01

    The equation of state of core alloys at pressures and temperatures near the solid-liquid coexistence curve is important for understanding the dynamics at the inner core boundary of the Earth and super-Earths. Here, we present a series of laser driven shock experiments on textured polycrystalline Fe-15Si. These experiments were conducted at the Omega and Omega EP laser facilities. Particle velocities in the Fe-15Si samples were measured using a line VISAR and were used to infer the thermodynamic state of the shocked samples. In situ x-ray diffraction measurements were used to probe the melting transition and investigate the potential decomposition of Fe-15Si in to hcp and B2 structures. This work examines the kinetic effects of decomposition due to the short time scale of dynamic compression experiments. In addition, the thermodynamic data collected in these experiments adds to a limited body of information regarding the equation of state of Fe-15Si, which is a candidate for the composition in Earth's outer core. Our experimental results show a highly textured solid phase upon shock compression to pressures ranging from 170 to 300 GPa. Below 320 GPa, we observe diffraction peaks consistent with decomposition of the D03 starting material in to an hcp and a cubic (potentially B2) structure. Upon shock compression above 320 GPa, the intense and textured solid diffraction peaks give way to diffuse scattering and loss of texture, consistent with melting along the Hugoniot. When comparing these results to that of pure iron, we can ascertain that addition of 15 wt% silicon increases the equilibrium melting temperature significantly, or that the addition of silicon significantly increases the metastability of the solid phase, relative to the liquid. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  4. The obtaining of iron acetate from processed iron comprising catalyst of ammonia synthesis

    International Nuclear Information System (INIS)

    Mansurov, M.M.; Lugovenko, A.N.; Mirzoeva, M.M.

    1993-01-01

    Present article is devoted to obtaining of iron acetate from processed iron comprising catalyst of ammonia synthesis. The method of synthesis of iron acetate from processed iron comprising catalyst of ammonia synthesis was elaborated. The structure of complex was determined.

  5. Determination of Surface Properties of Liquid Transition Metals

    International Nuclear Information System (INIS)

    Korkmaz, S. D.

    2008-01-01

    Certain surface properties of liquid simple metals are reported. Using the expression derived by Gosh and coworkers we investigated the surface entropy of liquid transition metals namely Fe, Co and Ni. We have also computed surface tensions of the metals concerned. The pair distribution functions are calculated from the solution of Ornstein-Zernike integral equation with Rogers-Young closure using the individual version of the electron-ion potential proposed by Fioalhais and coworkers which was originally developed for solid state. The predicted values of surface tension and surface entropy are in very good agreement with available experimental data. The present study results show that the expression derived by Gosh and coworkers is very useful for the surface entropy by using Fioalhais pseudopotential and Rogers-Young closure

  6. Mercury's Surface Magnetic Field Determined from Proton-Reflection Magnetometry

    Science.gov (United States)

    Winslow, Reka M.; Johnson, Catherine L.; Anderson, Brian J.; Gershman, Daniel J.; Raines, Jim M.; Lillis, Robert J.; Korth, Haje; Slavin, James A.; Solomon, Sean C.; Zurbuchen, Thomas H.; hide

    2014-01-01

    Solar wind protons observed by the MESSENGER spacecraft in orbit about Mercury exhibit signatures of precipitation loss to Mercury's surface. We apply proton-reflection magnetometry to sense Mercury's surface magnetic field intensity in the planet's northern and southern hemispheres. The results are consistent with a dipole field offset to the north and show that the technique may be used to resolve regional-scale fields at the surface. The proton loss cones indicate persistent ion precipitation to the surface in the northern magnetospheric cusp region and in the southern hemisphere at low nightside latitudes. The latter observation implies that most of the surface in Mercury's southern hemisphere is continuously bombarded by plasma, in contrast with the premise that the global magnetic field largely protects the planetary surface from the solar wind.

  7. Research on Laser Micro Polishing of SLS Technology Sintered Iron-Based Powder Surface

    Directory of Open Access Journals (Sweden)

    Gerda Vaitkūnaitė

    2015-03-01

    Full Text Available The article analyzes laser micro polishing of 1.2083 steel samples produced applying selective laser sintering (SLS method. The study has evaluated the distribution of the shape, size and temperature of the laser beam treated area in the surface layer of sintered and laser polished samples. Experimental tests have shown the impact of the technical parameters of laser micro polishing on the width and hardness of the impact zone of the treated sample. The microstructure analysis of laser treated and untreated areas of the material has been made.

  8. Determination of Conjugation Efficiency of Antibodies and Proteins to the Superparamagnetic Iron Oxide Nanoparticles by Capillary Electrophoresis with Laser-Induced Fluorescence Detection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, F.-H.; Yoshitake, Takashi [Karolinska Institutet, Department of Neuroscience (Sweden); Kim, Do-Kyung; Muhammed, Mamoun [Royal Institute of Technology, Materials Chemistry Division (Sweden); Bjelke, Boerje [MRI-Center, Experimental Unit, Karolinska Institutet (Sweden); Kehr, Jan [Karolinska Institutet, Department of Neuroscience (Sweden)], E-mail: Jan.Kehr@neuro.ki.se

    2003-04-15

    The method based on capillary electrophoresis with laser-induced fluorescence detection (CE/LIF) was developed for determination of magnetic iron oxide nanoparticles (hydrodynamic diameters of 100 nm) functionalized with molecules containing primary amino groups. The magnetic nanoparticles with carboxylic or aminopropyl-trimethoxysilane groups at their surface were conjugated to the model proteins (bovine serum albumin, BSA; streptavidin or goat anti-rabbit immunoglobulin G, IgG) using carbodiimide as a zero-length cross-linker.The nanoparticle-protein conjugates (hydrodynamic diameter 163-194 nm) were derivatized with naphthalene-2,3-dicarboxaldehyde reagent and separated by CE/LIF with a helium-cadmium laser (excitation at 442 nm, emission at 488 nm). The separations were carried out by using a fused-silica capillary (effective length 48 cm, inner diameter 75 um) and 100 mM sodium borate buffer (pH 9.2), the potential was 30 kV. The detection limit for BSA-conjugate was 1.3 pg/10 nl, i.e. about 20 amol. The present method provides an efficient and fast tool for sensitive determination of the efficacy of biomolecular functionalization of magnetic nanoparticles. The CE/LIF technique requires only negligible sample volumes for analysis, which is especially suitable for controlling the process of preparation of functionalized nanoparticles with unique properties aimed to be used for diagnostic or therapeutic purposes.

  9. Effects of Iron Concentration Level in Extracting Solutions from Contaminated Soils on the Determination of Zinc by Flame Atomic Absorption Spectrometry with Two Background Correctors

    Directory of Open Access Journals (Sweden)

    Christophe Waterlot

    2012-01-01

    Full Text Available Zinc and iron concentrations were determined after digestion, water, and three-step sequential extractions of contaminated soils. Analyses were carried out using flame absorption spectrometry with two background correctors: a deuterium lamp used as the continuum light source (D2 method and the high-speed self-reversal method (HSSR method. Regarding the preliminary results obtained with synthetic solutions, the D2 method often emerged as an unsuitable configuration for compensating iron spectral interferences. In contrast, the HSSR method appeared as a convenient and powerful configuration and was tested for the determination of zinc in contaminated soils containing high amounts of iron. Simple, fast, and interference-free method, the HSSR method allows zinc determination at the ppb level in the presence of large amounts of iron with high stability, sensitivity, and reproducibility of results. Therefore, the HSSR method is described here as a promising approach for monitoring zinc concentrations in various iron-containing samples without any pretreatment.

  10. Formation and structure of inhibitive molecular film of imidazole on iron surface

    International Nuclear Information System (INIS)

    Kokalj, Anton

    2013-01-01

    Highlights: ► Atomic scale details of interaction between imidazole and Fe(1 0 0) elucidated by DFT calculations. ► Imidazole dehydrogenates upon adsorption with the C2-H bond cleaved. ► Stablest identified structure consists of high coverage C2 dehydrogenated imidazoles. ► Passivation of Fe(1 0 0) due to strong adsorbate-surface bond and high adsorbate coverage. ► Previously suggested polymerization of imidazole molecules at high coverage is found improbable. - Abstract: Adsorption of imidazole on clean Fe(1 0 0) was addressed by DFT calculations. It is shown that even though the imidazole in protonated form binds stronger to the surface than the neutral form, it is prone to deprotonation (dehydrogenation) resulting in neutral form, which further dehydrogenates due to the breaking of the C2–H bond. Thermodynamically the stablest identified structures thus consist of strongly bound and densely packed C2 dehydrogenated imidazole molecules, which may act as a thin protective film. On the other hand, the polymerization of imidazole molecules upon adsorption has been found improbable.

  11. Determination of natural radioactivity of groundwater and surface of Brumadinho and Nova Lima, Brazil

    International Nuclear Information System (INIS)

    Faria, Ligia Santana de

    2013-01-01

    The municipalities of Brumadinho and Nova Lima are located in the metropolitan area of Belo Horizonte city. They are of ecological interest since they belong to an Environmental Protection Area, which is located on a very important deposit of iron ore. In addition of mineral wealth, the region has a geological characteristic that includes quartzitic conglomerates associated with uranium and significant potential underground water with hydrogeological characteristics very particular and complex, as the Quartzite Aquifer, which belongs to a geological formation called the 'Moeda Formation'. In the present work radiometric measurements were performed for 44 water samples. The samples were collected in four geographical points, three of them situated in Brumadinho (surface water) and one point situated in Nova Lima municipality (underground water). The period of sampling extended for a thirteen months period. Some of these locations was used as an alternative sampling point. Uranium and thorium concentrations of the samples were determined using an Inductively Coupled Plasma Mass Spectrometer. The content of gross alpha and gross beta activity, and the concentration of the radionuclides 226 Ra, 228 Ra e 210 Pb were determinate by using Spectrometer Liquid Scintillation. In this case was necessary to calibrate the spectrometer using 241 Am e 90 Sr/ 90 Y standards. The resultants values were compared with those recommended by the World Health Organization, Ministry of Health and the National Council of the Environment. The maximum level of water natural radioactivity found was 0,275 ± 0,052 Bq.L -1 for gross alpha radiation, 0,130 ± 0,046 Bq.L -1 for 226 Ra and 0,096 ± 0,005 Bq.L-1 for 228 Ra. The levels of gross beta activity and 210 Pb were below the detection limit. The maximum concentrations of uranium and thorium found were 0,068 μg.L -1 and 0.027 μg.L -1 respectively. (author)

  12. Modulatory Role of Surface Coating of Superparamagnetic Iron Oxide Nanoworms in Complement Opsonization and Leukocyte Uptake

    DEFF Research Database (Denmark)

    Inturi, Swetha; Wang, Guankui; Chen, Fangfang

    2015-01-01

    demonstrated that neutrophils, monocytes, lymphocytes and eosinophils took up SPIO NWs, and the uptake was prevented by EDTA (a general complement inhibitor) and by antiproperdin antibody (an inhibitor of the alternative pathway of the complement system). Cross-linking and hydrogelation of SPIO NWs surface...... by epichlorohydrin decreased C3 opsonization in mouse serum, and consequently reduced the uptake by mouse leukocytes by more than 70% in vivo. Remarkably, the cross-linked particles did not show a decrease in C3 opsonization in human serum, but showed a significant decrease (over 60%) of the uptake by human...... leukocytes. The residual uptake of cross-linked nanoparticles was completely blocked by EDTA. These findings demonstrate species differences in complement-mediated nanoparticle recognition and uptake by leukocytes, and further show that human hemocompatibility could be improved by inhibitors of complement...

  13. Iron oxide magnetic nanoparticles with versatile surface functions based on dopamine anchors

    Science.gov (United States)

    Mazur, Mykola; Barras, Alexandre; Kuncser, Victor; Galatanu, Andrei; Zaitzev, Vladimir; Turcheniuk, Kostiantyn V.; Woisel, Patrice; Lyskawa, Joel; Laure, William; Siriwardena, Aloysius; Boukherroub, Rabah; Szunerits, Sabine

    2013-03-01

    The synthesis of multifunctional magnetic nanoparticles (MF-MPs) is one of the most active research areas in advanced materials as their multifunctional surfaces allow conjugation of biological and chemical molecules, thus making it possible to achieve target-specific diagnostic in parallel to therapeutics. We report here a simple strategy to integrate in a one-step reaction several reactive sites onto the particles. The preparation of MF-MPs is based on their simultaneous modification with differently functionalized dopamine derivatives using simple solution chemistry. The formed MF-MPs show comparable magnetic properties to those of naked nanoparticles with almost unaltered particle size of around 25 nm. The different termini, amine, azide and maleimide functions, enable further functionalization of MF-MPs by the grafting-on approach. Michael addition, Cu(i) catalyzed « click » chemistry and amidation reactions are performed on the MF-MPs integrating subsequently 6-(ferrocenyl)-hexanethiol, horseradish peroxidase (HRP) and mannose.

  14. Reluctance network modelling of surface permanent magnet motor considering iron nonlinearities

    International Nuclear Information System (INIS)

    Raminosoa, T.; Farooq, J.A.; Djerdir, A.; Miraoui, A.

    2009-01-01

    This paper presents a simple, quick and precise nonlinear reluctance network modelling of an in-wheel surface permanent magnet motor. The saturation of the ferromagnetic materials is considered and a simple air-gap length function is used to take the slotting effect into account. The topology and the reluctance values of the air-gap network are automatically computed for any rotor position. Thus, the proposed technique allows a steady state time stepping simulation. For any saturation level, there is a good accordance with the finite element method for the torque and back EMF. Moreover, the model accurately predicts the effect of the demagnetization. The proposed model can be advantageously used for a geometry optimization as well as for the diagnosis of demagnetization.

  15. The nanophase iron mineral(s) in Mars soil

    Science.gov (United States)

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Mancinelli, R. L.; Gehring, A. U.

    1993-01-01

    A series of surface-modified clays containing nanophase (np) iron oxide/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these "Mars-soil analogs" were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging, specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The clay acted as an effective matrix, both chemically and sterically, preventing the major part of the synthesized iron oxides from ripening, i.e., growing and developing larger crystals. The precipitated iron oxides appear as isodiametric or slightly elongated particles in the size range 1-10 nm, having large specific surface area. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxy mineral such as "green rust," or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable maghemite (gamma-Fe2O3) by mild heat treatment and then to nanophase hematite (alpha-Fe2O3) by extensive heat treatment. After mild heating, the iron-enriched clay became slightly magnetic, to the extent that it adheres to a hand-held magnet, as was observed with Mars soil. The chemical reactivity of the iron-enriched clays strongly resembles, and offers a plausible mechanism

  16. Voltammetric determination of metal impurities on semiconductor surface

    International Nuclear Information System (INIS)

    Knyazeva, E.P.; Mokrousov, G.M.; Volkova, V.N.

    1995-01-01

    A modification of voltamperometric method used for analysis of semiconductor surfaces which make it possible to exclude a contact between surface and background solution. This technique is based on solubility of elemental metal forms in low melting electroconductor systems (e.g., in mercury. The voltampere characteristics of amalgams formed are then studied. The suggested method is simple, rapid, and makes it possible to perform a nondestructive qualitative analysis of the sample surface area measuring about 10 -3 cm -2 and more. 4 refs.; 2 figs

  17. Determination of surface dose rate for cloisonne using thermoluminescent dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Hengyuan, Zhao; Yulian, Zhang

    1985-07-01

    In this paper, the measuring method and results of surface dose rate of cloisonne using CaSO/sub 4/ Dy-Teflon foil dosimeter are described. The surface dose rate of all products are below 0.015 mrad/h. These products contain 42 sorts of jewelery and 20 sets of wares (such as vases, plates, ash-trays, etc.). Most of the data fall within the range of natural background. For comparison, some jewelery from Taiwan and 3 vases from Japan are measured. The highest surface dose rate of 0.78 mrad/h is due to the necklace jewelery from Taiwan.

  18. Iron oxide nanoparticles surface coating and cell uptake affect biocompatibility and inflammatory responses of endothelial cells and macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Orlando, Antonina [University of Milano-Bicocca, Department of Health Sciences (Italy); Colombo, Miriam; Prosperi, Davide [University of Milano-Bicocca, Department of Biotechnology and Biosciences (Italy); Gregori, Maria; Panariti, Alice; Rivolta, Ilaria; Masserini, Massimo; Cazzaniga, Emanuela, E-mail: emanuela.cazzaniga@unimib.it [University of Milano-Bicocca, Department of Health Sciences (Italy)

    2015-09-15

    Engineered iron oxide nanoparticles (IONP) offer the possibility of a wide range of medical uses, from clinical imaging to magnetically based hyperthermia for tumor treatment. These applications require their systemic administration in vivo. An important property of nanoparticles is their stability in biological media. For this purpose, a multicomponent nanoconstruct combining high colloidal stability and improved physical properties was synthesized and characterized. IONP were coated with an amphiphilic polymer (PMA), which confers colloidal stability, and were pegylated in order to obtain the nanoconstruct PEG-IONP-PMA. The aim of this study was to utilize cultured human endothelial cells (HUVEC) and murine macrophages, taken as model of cells exposed to NP after systemic administration, to assess the biocompatibility of PEG-IONP-PMA (23.1 ± 1.4 nm) or IONP-PMA (15.6 ± 3.4 nm). PEG-IONP-PMA, tested at different concentrations as high as 20 μg mL{sup −1}, exhibited no cytotoxicity or inflammatory responses. By contrast, IONP-PMA showed a concentration-dependent increase of cytotoxicity and of TNF-α production by macrophages and NO production by HUVECs. Cell uptake analysis suggested that after PEGylation, IONP were less internalized either by macrophages or by HUVEC. These results suggest that the choice of the polymer and the chemistry of surface functionalization are a crucial feature to confer to IONP biocompatibility.

  19. Comparison of Deferasirox and deferoxamine treatment in iron-overloaded patients: liver iron concentration determined by quantitative MRI-R_2"*

    International Nuclear Information System (INIS)

    Peng Peng; Long Liling; Huang Zhongkui; Zhang Ling; Feng Xiao; Li Xiaohui; Yang Gaohui

    2013-01-01

    Objective: To explore the value of MRI-R_2"* and to compare clinical effect of two iron chelators (Deferasirox and deferoxamine) in iron-overloaded patients. Methods: By completely randomized balanced design, 24 iron-overloaded patients were randomly divided into 2 groups, which consisted of 12 patients treated with Deferasirox and 12 patients treated with deferoxamine. The planned Deferasirox dose was 40 mg · kg"-"1 · d"-"1, and the deferoxamine dose was no less than 50 mg · kg"-"1 · d"-"1. All patients underwent quantitative MRI at the time points of the primary screening, 6 months and 12 months. Pair Wilcoxon rank sum test was used to compare the differences of liver R_2"* values of the 2 groups at various time points respectively. Wilcoxon rank sum test was used to compare the differences of change rate of liver R_2"* values between the two groups at the time point of 6 months, 12 months, respectively. Results: Deferasirox group's liver R_2"* values of primary screening, 6 months and 12 months were 1081, 889 and 712 Hz, while deferoxamine group's liver R_2"* values were 1042, 838 and 488 Hz. There was no statistically significant difference between liver R_2"* values of two groups at primary screening (Z = -0.029, P > 0.05). The change rate of liver R_2"* of Deferasirox group at 12 month was -32%, while it was -58% for the deferoxamine group, and there was statistically significant difference between the two groups (Z = -3.060, P < 0.01). The change rate of serum ferritin of Deferasirox group at 12 month was -15%, while it was -55% for the deferoxamine group, and there was statistically significant difference between the two groups (Z = -2.945, P < 0.01). Conclusion: By using MRI-R_2"*, it suggest that both Deferasirox and deferoxamine can effectively remove liver iron and deferoxamine is superior to Deferasirox. (authors)

  20. Determination of rare earth elements in products of Chadormalu iron ore concentrator plant (Iran) from beneficiation point of view

    International Nuclear Information System (INIS)

    Jorjani, E.; Bagherieh, A. H.; Rezai, B.

    2007-01-01

    :Different samples have been prepared from different products in Chadormalu iron ore concentrator plant: Low intensity magnetite separators concentrate (magnetite concentrate), reverse flotation tail (final hematite concentrate), flotation concentrate (apatite concentrate), final tail (L.I. M.S. tail + reverse flotation concentrate + apatite flotation tail). The samples were used for rare earth elements (REEs) distribution and origin studies. The assay of REEs was determined by ICP-MS spectrometry. The amount of total (light and heavy) REEs were 9631, 291, 199, 2236 ppm and the distributions were 19.3, 3.6, 10.1, 67% in flotation concentrate (apatite concentrate), reverse flotation tail (hematite concentrate), magnetite concentrate and total tail respectively. About 19.3% of total REEs were distributed in apatite concentrate with an assay of 9631 ppm. Therefore, further studies have been conducted on this product. According to the Xray studies the minerals of fluoroapatite, ankerite and calcite are the main mineral phases in apatite concentrate which the apatite is dominant among them. The scanning electron microscopy studies were shown that the high amount of REEs distributed on fluoroapatite mineral. The results have clearly shown that the apatite concentrate that is a by product of iron dressing in Chadormalu plant, with a low economical value and left without any further treatment, can be used as a significant source of REEs. According to this characterization studies, the recovery of a mixed rare earth oxide from fluoroapatite is possible either with the treatment of liquors from the total dissolution of the ore in nitric acid or with the proposed treatment of the phosphogypsum by-product from the conventional sulphuric acid route and the recovery of rare earth oxides from phosphoric acid sludges that the detailed flowsheet needs further extraction work

  1. Current understanding of iron homeostasis.

    Science.gov (United States)

    Anderson, Gregory J; Frazer, David M

    2017-12-01

    Iron is an essential trace element, but it is also toxic in excess, and thus mammals have developed elegant mechanisms for keeping both cellular and whole-body iron concentrations within the optimal physiologic range. In the diet, iron is either sequestered within heme or in various nonheme forms. Although the absorption of heme iron is poorly understood, nonheme iron is transported across the apical membrane of the intestinal enterocyte by divalent metal-ion transporter 1 (DMT1) and is exported into the circulation via ferroportin 1 (FPN1). Newly absorbed iron binds to plasma transferrin and is distributed around the body to sites of utilization with the erythroid marrow having particularly high iron requirements. Iron-loaded transferrin binds to transferrin receptor 1 on the surface of most body cells, and after endocytosis of the complex, iron enters the cytoplasm via DMT1 in the endosomal membrane. This iron can be used for metabolic functions, stored within cytosolic ferritin, or exported from the cell via FPN1. Cellular iron concentrations are modulated by the iron regulatory proteins (IRPs) IRP1 and IRP2. At the whole-body level, dietary iron absorption and iron export from the tissues into the plasma are regulated by the liver-derived peptide hepcidin. When tissue iron demands are high, hepcidin concentrations are low and vice versa. Too little or too much iron can have important clinical consequences. Most iron deficiency reflects an inadequate supply of iron in the diet, whereas iron excess is usually associated with hereditary disorders. These disorders include various forms of hemochromatosis, which are characterized by inadequate hepcidin production and, thus, increased dietary iron intake, and iron-loading anemias whereby both increased iron absorption and transfusion therapy contribute to the iron overload. Despite major recent advances, much remains to be learned about iron physiology and pathophysiology. © 2017 American Society for Nutrition.

  2. Shaping optimal zinc coating on the surface of high-quality ductile iron casting. Part I – Moulding technologies vs. zinc coating

    Directory of Open Access Journals (Sweden)

    Szczęsny A.

    2017-03-01

    Full Text Available Studies have demonstrated that in the process of hot dip galvanizing the decisive influence on the mechanism of zinc coating formation and properties has the quality of the mechanically untreated (raw surface layer of the galvanized product. The terms “casting surface layer” denote various parameters of the microstructure, including the type of metal matrix, the number of grains and the size of graphite nodules, possible presence of hard spots (the precipitates of eutectic cementite and parameters of the surface condition. The completed research has allowed linking the manufacturing technology of ductile iron castings with the process of hot dip galvanizing.

  3. Determination of antimony by electrochemical hydride generation atomic absorption spectrometry in samples with high iron content using chelating resins as on-line removal system

    International Nuclear Information System (INIS)

    Bolea, E.; Arroyo, D.; Laborda, F.; Castillo, J.R.

    2006-01-01

    A method for the removal of the interference caused by iron on electrochemical generation of stibine is proposed. It consists of a chelating resin Chelex 100 column integrated into a flow injection system and coupled to the electrochemical hydride generator quartz tube atomic absorption spectrometer (EcHG-QT-AAS). Iron, as Fe(II), is retained in the column with high efficiency, close to 99.9% under optimal conditions. No significant retention was observed for Sb(III) under same conditions and a 97 ± 5% signal recovery was achieved. An electrochemical hydride generator with a concentric configuration and a reticulated vitreous carbon cathode was employed. The system is able to determine antimony concentrations in the range of ng ml -1 in presence of iron concentrations up to 400 mg l -1 . The procedure was validated by analyzing PACS-2 marine sediments reference material with a 4% (w/w) iron content and a [Fe]:[Sb] ratio of 4000:1, which caused total antimony signal suppression on the electrochemical hydride generation system. A compost sample with high iron content (0.7%, w/w), was also analyzed. A good agreement was found on both samples with the certified value and the antimony concentration determined by ICP-MS, respectively

  4. Antioxidant mechanism of milk mineral-high-affinity iron binding.

    Science.gov (United States)

    Allen, K; Cornforth, D

    2007-01-01

    Milk mineral (MM), a by-product of whey processing, is an effective antioxidant in meat systems, but the antioxidant mechanism has not been established. MM has been postulated to chelate iron and prevent iron-catalysis of lipid oxidation. The objective of this research was to examine this putative mechanism. MM was compared to sodium tripolyphosphate (STPP), calcium phosphate monobasic (CPM), and calcium pyrophosphate (CPP) to determine iron-binding capacity, sample solubility, and eluate soluble phosphorus after treating samples with a ferrous chloride standard. Scanning electron microscopy with energy-dispersive X-ray analysis was used to localize minerals on iron-treated MM particle surfaces. Histochemical staining for calcium was performed on raw and cooked ground beef samples with added MM. MM bound more iron per gram (P compounds, and was much less soluble (P iron across the MM particle surface, directly demonstrating iron binding to MM particles. Unlike other common chelating agents, such as STPP and citrate, histochemical staining demonstrated that MM remained insoluble in ground beef, even after cooking. The ability of MM to bind iron and remain insoluble may enhance its antioxidant effect by removing iron ions from solution. However, MM particles must be small and well distributed in order to adequately bind iron throughout the food system.

  5. Simultaneous determination of cadmium, iron and tin in canned foods using high-resolution continuum source graphite furnace atomic absorption spectrometry.

    Science.gov (United States)

    Leao, Danilo J; Junior, Mario M S; Brandao, Geovani C; Ferreira, Sergio L C

    2016-06-01

    A method was established to simultaneously determine cadmium, iron and tin in canned-food samples using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS). The quantification step has been performed using the primary line (228.802nm) for cadmium and the adjacent secondary lines (228.725nm and 228.668nm) for iron and tin, respectively. The selected chemical modifier was an acid solution that contained a mixture of 0.1% (w/v) Pd and 0.05% (w/v) Mg. The absorbance signals were measured based on the peak area using 3 pixels for cadmium and 5 pixels for iron and tin. Under these conditions, cadmium, iron and tin have been determined in canned-food samples using the external calibration technique based on aqueous standards, where the limits of quantification were 2.10ngg(-1) for cadmium, 1.95mgkg(-1) for iron and 3.00mgkg(-1) for tin, and the characteristic masses were 1.0pg for cadmium, 0.9ng for iron and 1.1ng for tin. The precision was evaluated using two solutions of each metal ion, and the results, which were expressed as the relative standard deviation (RSD%), were 3.4-6.8%. The method accuracy for cadmium and iron was confirmed by analyzing a certified reference material of apple leaves (NIST 1515), which was supplied by NIST. However, for tin, the accuracy was confirmed by comparing the results of the proposed method and another analytical technique (inductively coupled plasma optical emission spectrometry). The proposed procedure was applied to determine cadmium, iron and tin in canned samples of peeled tomato and sardine. Eleven samples were analyzed, and the analyte concentrations were 3.57-62.9ngg(-1), 2.68-31.48mgkg(-1) and 4.06-122.0mgkg(-1) for cadmium, iron and tin, respectively. In all analyzed samples, the cadmium and tin contents were lower than the permissible maximum levels for these metals in canned foods in the Brazilian legislation. Copyright © 2016. Published by Elsevier B.V.

  6. Determination of iron, cobalt and zinc in caries teeth by neutron activation analysis

    International Nuclear Information System (INIS)

    Moriwaki, Kazunari; Shimpuku, Yasuhiro; Furuyama, Shunsuke

    1999-01-01

    The concentration of Fe, Zn and Co in caries teeth was determined by neutron activation analysis to compare with those of complete impacted wisdom teeth. In order to investigate the distribution of three elements, molar teeth were separated not by conventional method like precipitation or UV absorption method but by ashing method. Furthermore, the same elements for dental pulp and softened dentin were determined. The following results were obtained: The concentration of three elements (Fe, Zn and Co) in enamel, dentin and cementum of caries teeth was higher than that in control teeth. Enamel contained more Fe and Co than those in dentin or cementum, whereas Zn was found to be evenly distributed in three parts of the teeth. The concentration of the elements was Zn>Fe>Co in softened dentin, Fe>Zn>Co in dental pulp. (author)

  7. Determination of small amounts of aluminum in iron and steel by x-ray fluorescence analysis

    International Nuclear Information System (INIS)

    Ito, Minao; Sato, Shoki; Narita, Masanao

    1981-01-01

    The accuracy of X-ray fluorescence analysis for determining aluminum in steel is generally poor when the aluminum content is below 0.1%. In this study, it is confirmed that the existence of inhomogeneous acid-insoluble aluminum causes the poor accuracy of X-ray fluorescence analysis. The accuracy can be improved by adding granular ferro-zirconium to molten steel when sampling. By using this method, the accuracy of determining aluminum was 0.0024% for low alloy steels and 0.0022% for stainless steels as the standard deviation obtained for a series of differences between an analytical result and a standard value. Corrections for overlapping of the chromium spectrum, and for absorption and enhancement effects of co-existent elements are not necessary for the analysis of low alloy steels, whereas these corrections are necessary for the analysis of stainless steels. (author)

  8. Determining the size of nanoparticles in the example of magnetic iron oxide core-shell systems

    Science.gov (United States)

    Jarzębski, Maciej; Kościński, Mikołaj; Białopiotrowicz, Tomasz

    2017-08-01

    The size of nanoparticles is one of the most important factors for their possible applications. Various techniques for the nanoparticle size characterization are available. In this paper selected techniques will be considered base on the prepared core-shell magnetite nanoparticles. Magnetite is one of the most investigated and developed magnetic material. It shows interesting magnetic properties which can be used for biomedical applications, such as drug delivery, hypothermia and also as a contrast agent. To reduce the toxic effects of Fe3O4, magnetic core was covered by dextran and gelatin. Moreover, the shell was doped by fluorescent dye for confocal microscopy investigation. The main investigation focused on the methods for particles size determination of modified magnetite nanoparticles prepared with different techniques. The size distribution were obtained by nanoparticle tracking analysis, dynamic light scattering and transmission electron microscopy. Furthermore, fluorescent correlation spectroscopy (FCS) and confocal microscopy were used to compare the results for particle size determination of core-shell systems.

  9. Determination of chromium, iron, zinc and calcium contents in pastes commercialized at Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Luizar-Obrigon, Celina; Baruffaldi, Renato

    1999-01-01

    Foods, in particular pastes, in the industrial manufacture process are in contact with equipment made of stainless steel, containing Cr, fe and Zn in their structures. The aim of this study is to verify Cr, Fe and Zn migration from the stainless steel equipment to the food during the industrial process. Instrumental neutron activation analysis was applied to determine the concentrations of Cr, Fe, Zn and Ca in four brands of pastes. Only the migration of chromium was be observed. (author)

  10. Urban Surface Radiative Energy Budgets Determined Using Aircraft Scanner Data

    Science.gov (United States)

    Luvall, Jeffrey C.; Quattrochi, Dale A.; Rickman, Doug L.; Estes, Maury G.; Arnold, James E. (Technical Monitor)

    2002-01-01

    It is estimated that by the year 2025, 80% of the world's population will live in cities. The extent of these urban areas across the world can be seen in an image of city lights from the Defense Meteorological Satellite Program. In many areas of North America and Europe, it is difficult to separate individual cities because of the dramatic growth and sprawl of urbanized areas. This conversion of the natural landscape vegetation into man-made urban structures such as roads and buildings drastically alter the regional surface energy budgets, hydrology, precipitation patterns, and meteorology. One of the earliest recognized and measured phenomena of urbanization is the urban heat island (UHI) which was reported as early as 1833 for London and 1862 for Paris. The urban heat island results from the energy that is absorbed by man-made materials during the day and is released at night resulting in the heating of the air within the urban area. The magnitude of the air temperature difference between the urban and surrounding countryside is highly dependent on the structure of the urban area, amount of solar immolation received during the day, and atmospheric conditions during the night. These night time air temperature differences can be in the range of 2 to 5 C. or greater. Although day time air temperature differences between urban areas and the countryside exists during the day, atmospheric mixing and stability reduce the magnitude. This phenomena is not limited to large urban areas, but also occurs in smaller metropolitan areas. The UHI has significant impacts on the urban air quality, meteorology, energy use, and human health. The UPI can be mitigated through increasing the amount of vegetation and modification of urban surfaces using high albedo materials for roofs and paved surfaces. To understand why the urban heat island phenomenon exists it is useful to define the surface in terms of the surface energy budget. Surface temperature and albedo is a major component of

  11. Reverse flow injection spectrophotometric determination of ciprofloxacin in pharmaceuticals using iron from soil as a green reagent

    Science.gov (United States)

    Palamy, Sysay; Ruengsitagoon, Wirat

    2018-02-01

    A novel reverse flow injection spectrophotometric method for the determination of ciprofloxacin was successfully combined with the on-line introduction of an iron solution extracted from soil as green reagent. The assay was optimized by a univariate method to select the optimum conditions for the highest absorbance and highest stability of the complex. Beer-Lambert's law (λmax = 440 nm) is obeyed in the range 0.5-50 μg mL- 1 with a correlation coefficient (r2) of 0.9976 and 0.9996 using soil as green reagent from Khon Kaen, Thailand and Vientiane, Laos, respectively. The average percentage recoveries were in the range of 98.55-102.14% and the precision was in the range of 0.80-1.73%. The limit of detection and the limit of quantitation were 0.20 and 0.69 μg mL- 1, respectively, with a sampling rate of over 46 samples h- 1. The method was successfully applied to the determination of ciprofloxacin in commercial pharmaceutical formulations. The results were in good agreement with those obtained by the reference HPLC method using a t-test at 95% of confidence level for comparison. This method is suitable for laboratories looking for alternative analytical methods using green reagents.

  12. Volumetric Titrations Using Electrolytically Generated Reagents for the Determination of Ascorbic Acid and Iron in Dietary Supplement Tablets: An Undergraduate Laboratory Experiment

    Science.gov (United States)

    Scanlon, Christopher; Gebeyehu, Zewdu; Griffin, Kameron; Dabke, Rajeev B.

    2014-01-01

    An undergraduate laboratory experiment for the volumetric quantitative analysis of ascorbic acid and iron in dietary supplement tablets is presented. Powdered samples of the dietary supplement tablets were volumetrically titrated against electrolytically generated reagents, and the mass of dietary reagent in the tablet was determined from the…

  13. Determining eyeball surface area directly exposed to the effects of external factors.

    Science.gov (United States)

    Juliszewski, Tadeusz; Kadłuczka, Filip; Kiełbasa, Paweł

    2016-01-01

    This article discusses determining the surface area of eyeballs of men and women exposed to the direct effects of external factors in the working environment. For one eye, the mean surface is 172-182 mm(2). The determined surface area can be used in formulas for calculating the exposure of eyeballs to harmful chemical substances in workplace air.

  14. DETERMINATION OF SUITABLE CHEMICAL EXTRACTION METHODS FOR AVAILABLE IRON CONTENT OF THE SOILS FROM EDIRNE PROVINCE IN TURKEY

    Directory of Open Access Journals (Sweden)

    A ADILOGLU

    2002-12-01

    Full Text Available The aim of this research was to determine the available iron (Fe content of the soils of Edirne Province and the most suitable chemical extraction method. Eight chemical extraction methods (0.005 M DTPA + 0.01 M CaCl2 + 0.1 M TEA; 0.05 M HCl + 0.012 M H2SO4; 1 M NH4OAc (pH: 4.8; 0.01 M EDTA + 1 M NH4OAc; 1 M MgCl2; 0.01 M EDTA + 1 M (NH42CO3; 0.005 M DTPA + 1 M NH4HCO3 and 0.001 M EDDHA methods and six biological indices (dry matter yield, Fe concentration, Fe uptake, relative dry matter yield, relative Fe concentration, relative Fe uptake were compared. Biological indices were determined with Barley (Hordeum vulgare L. grown under greenhouse conditions. At the end of the experiment, the highest correlation coefficients (r were determined to be between the 0.005 M DTPA + 0.01 M CaCl2 + 0.1 M TEA method and the biological indices and between the 0.005 M DTPA + 1 M NH4HCO3 method and the biological indices. The correlation coefficients (r for the 0.005 M DTPA + 0.01 M CaCl2 +0.1 M TEA method were r=0.621**; r=0.823**; r=0.810**; r=0.433**; r=0.558** and r=0.640** and for the 0.005 M DTPA + 1 M NH4HCO3 method r=0.618** ; r=0.520**; r=0.679**; r=0.521**; r=0.492** and r=0.641**, (**:p<0.01 respectively. These extraction methods, among all the methods tested were suggested for the determination of available Fe content of Edirne Province soils.

  15. Highly Selective and Sensitized Spectrophotometric Determination of Iron (3) Following Potentiometric Study

    International Nuclear Information System (INIS)

    Shokrollahi, A.; Ghaedi, M.; Rajabi, H.R.

    2007-01-01

    A simple, selective and sensitized spectrophotometric method for determination of trace amounts of Fe 3+ ion in tap and waste water solutions has been described. The spectrophotometric determination of Fe 3+ ion using Ferron in the presence of N,N-Dodecy trimethylammonium bromide (DTAB) has been carried out. The Beer's law is obeyed over the concentration range of 0.05-2.6 μg mL -1 of Fe 3+ ion with the relative standard deviation (RSD %) 3 L mol -1 cm -1 . Potentiometric pH titration has been used for prediction of protonation constants of ferron, and evaluating its stoichiometry and respective stability constant with Fe 3+ ion. As it is obvious the most likely species of ferron alone and its complexes are LH (log=7.64), LH 2 (logK=10.52), LH 3 (logK=11.74) and ML 2 (logβ= 23.68), ML 3 (logβ23.68), ML 3 H (logβ= 23.68), ML 3 H 2 (logβ= 23.68) and ML(OH) 2 (logβ=23.68) respectively

  16. Surface versus Edge-Based Determinants of Visual Recognition.

    Science.gov (United States)

    Biederman, Irving; Ju, Ginny

    1988-01-01

    The latency at which objects could be identified by 126 subjects was compared through line drawings (edge-based) or color photography (surface depiction). The line drawing was identified about as quickly as the photograph; primal access to a mental representation of an object can be modeled from an edge-based description. (SLD)

  17. Surface determinants of low density lipoprotein uptake by endothelial cells

    International Nuclear Information System (INIS)

    Goeroeg, P.; Pearson, J.D.

    1984-01-01

    The surface sialic acid content of aortic endothelial cells in vitro was substantially lower in sparse cultures than at confluence. Binding of LDL to endothelial cells did not change at different culture densities and was unaffected by brief pretreatment with neuraminidase to partially remove surface sialic acid residues. In contrast, internalisation of LDL declined by a factor of 3 between low density cell cultures and confluent monolayers; neuraminidase pretreatment increased LDL uptake and the effect was most marked (>10-fold) at confluence. Pretreatment with cationised ferritin, which removed most of the surface sialic acid residues as well as glycosaminoglycans, increased LDL internalisation by up to 20-fold, again with most effect on confluent monolayers. Thus LDL uptake is inversely correlated with sialic acid content. We conclude that changes in the surface density of sialic acid (and possibly other charged) residues significantly modulate endothelial LDL uptake, and suggest that focal increases in LDL accumulation during atherogenesis may be related to alterations in endothelial endocytic properties at sites of increased cell turnover or damage. (author)

  18. Determining the energetics of vicinal perovskite oxide surfaces

    NARCIS (Netherlands)

    Wessels, W.A.; Bollmann, Tjeerd Rogier Johannes; Koster, Gertjan; Zandvliet, Henricus J.W.; Rijnders, Augustinus J.H.M.

    2017-01-01

    The energetics of vicinal SrTiO3(001) and DyScO3(110), prototypical perovskite vicinal surfaces, has been studied using topographic atomic force microscopy imaging. The kink formation and strain relaxation energies are extracted from a statistical analysis of the step meandering. Both perovskite

  19. Transport of surface-modified iron nanoparticle in porous media and application to arsenic(III) remediation

    International Nuclear Information System (INIS)

    Kanel, Sushil Raj; Nepal, Dhriti; Manning, Bruce; Choi, Heechul

    2007-01-01

    The surface-modified iron nanoparticles (S-INP) were synthesized, characterized and tested for the remediation of arsenite (As(III)), a well known toxic groundwater contaminant of concern. The S-INP material was fully dispersed in the aqueous phase with a particle size distribution of 2-10 nm estimated from high-resolution transmission electron microscopy (HR-TEM). X-ray photoelectron spectroscopy (XPS) revealed that an Fe(III) oxide surface film was present on S-INP in addition to the bulk zero-valent Fe 0 oxidation state. Transport of S-INP through porous media packed in 10 cm length column showed particle breakthroughs of 22.1, 47.4 and 60 pore volumes in glass beads, unbaked sand, and baked sand, respectively. Un-modified INP was immobile and aggregated on porous media surfaces in the column inlet area. Results using S-INP pretreated 10 cm sand-packed columns containing ∼2 g of S-INP showed that 100 % of As(III) was removed from influent solutions (flow rate 1.8 mL min -1 ) containing 0.2, 0.5 and 1.0 mg L -1 As(III) for 9, 7 and 4 days providing 23.3, 20.7 and 10.4 L of arsenic free water, respectively. In addition, it was found that 100% of As(III) in 0.5 mg/L solution (flow rate 1.8 mL min -1 ) was removed by S-INP pretreated 50 cm sand packed column containing 12 g of S-INP for more than 2.5 months providing 194.4 L of arsenic free water. Field emission scanning electron microscopy (FE-SEM) showed S-INP had transformed to elongated, rod-like shaped corrosion product particles after reaction with As(III) in the presence of sand. These results suggest that S-INP has great potential to be used as a mobile, injectable reactive material for in-situ sandy groundwater aquifer treatment of As(III)

  20. Spectrophotometric Determination of Iron(II after Solid Phase Extraction of Its 2,2′ Bipyridine Complex on Silica Gel-Polyethylene Glycol

    Directory of Open Access Journals (Sweden)

    Nahid Pourreza

    2013-01-01

    Full Text Available A new solid phase extraction procedure was developed for preconcentration of iron(II using silica gel-polyethylene glycol (silica-PEG as an adsorbent. The method is based on retention of iron(II as 2,2′ bipyridine complex on silica-PEG. The retained complex is eluted by 1.0 mol L−1 of sulfuric acid-acetone mixture (1:2 and its absorbance is measured at 518 nm, spectrophotometrically. The effects of different parameters such as pH, concentration of the reagent, eluting reagent, sample volume, amount of adsorbent, and interfering ions were investigated. The calibration graph was linear in the range of 1–60 ng mL−1 of iron(II. The limit of detection based on 3Sb was 0.57 ng mL−1 and relative standard deviations (R.S.D for ten replicate measurements of 12 and 42 ng mL−1 of iron(II were 2.4 and 1.7%, respectively. The method was applied to the determination of of iron(II in water, multivitamin tablet, and spinach samples.

  1. Effects of soluble flavin on heterogeneous electron transfer between surface-exposed bacterial cytochromes and iron oxides

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zheming; Shi, Zhi; Shi, Liang; White, Gaye F.; Richardson, David J.; Clarke, Thomas A.; Fredrickson, Jim K.; Zachara, John M.

    2015-08-25

    Dissimilatory iron-reducing bacteria can utilize insoluble Fe(Mn)-oxides as a terminal electron acceptor under anaerobic conditions. For Shewanella species specifically, some evidence suggests that iron reduction is associated with the secretion of flavin mononucleotide (FMN) and riboflavin that are proposed to mediate electron transfer (Marsili et al., 2008). In this work, we used methyl viologen (MV•+)-encapsulated, porin-cytochrome complex (MtrCAB) embedded liposomes (MELs) as a synthetic model of the Shewanella outer membrane to investigate the proposed mediating behavior of secreted flavins. The reduction kinetics of goethite, hematite and lepidocrocite (200 µM) by MELs ([MV•+] ~ 42 µM and MtrABC ≤ 1 nM) were determined in the presence FMN at pH 7.0 in N2 atmosphere by monitoring the concentrations of MV•+ and FMN through their characteristic UV-visible absorption spectra. Experiments were performed where i) FMN and Fe(III)-oxide were mixed and then reacted with the reduced MELs and ii) FMN was reacted with the reduced MELs followed by addition of Fe(III)-oxide. The redox reactions proceeded in two steps: a fast step that was completed in a few seconds, and a slower one lasting over 400 seconds. For all three Fe(III)-oxides, the initial reaction rate in the presence of a low concentration of FMN (≤ 1 µM) was at least a factor of five faster than those with MELs alone, and orders of magnitude faster than those by FMNH2, suggesting that FMN may serve as a co-factor that enhances electron transfer from outer-membrane c-cytochromes to Fe(III)-oxides. The rate and extent of the initial reaction followed the order of lepidocrocite > hematite > goethite, the same as their reduction potentials, implying thermodynamic control on reaction rate. However, at higher FMN concentrations (> 1 µM), the reaction rates for both steps decreased and varied inversely with FMN concentration, indicating that FMN inhibited the MEL to Fe(III)-oxide electron transfer

  2. The nanosphere iron mineral(s) in Mars soil

    Science.gov (United States)

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Mancinelli, R. L.; Gehring, A. U.

    1993-01-01

    A series of surface-modified clays containing nanophase (np) iron/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these 'Mars-soil analogs' were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxyl mineral such as 'green rust', or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable meaghemite (gamma-Fe203) by mild heat treatment and then to nanophase hematite (aplha-Fe203) by extensive heat treatment. Their chemical reactivity offers a plausible mechanism for the somewhat puzzling observations of the Viking biology experiments. Their unique chemical reactivities are attributed to the combined catalytic effects of the iron oxide/oxyhydroxide and silicate phase surfaces. The mode of formation of these (nanophase) iron oxides on Mars is still unknown.

  3. Direct reading spectrochemical determination of aluminium, iron and silicon in fluorite

    International Nuclear Information System (INIS)

    Roca, M.

    1966-01-01

    A quantitative spectrochemical method for the determination of Al, Fe and Si in fluorite has been worked out. The sample was supported in a graphite electrode with crater of 5 mm. in diameter, 2,5 mm deep, and burned by a d.c. are in a direct reading spectrometer. The excitation of samples has been studied without dilution as well as using graphite powder as diluent in the ratios 1:1, 1:4, and 1:9; the latter factor was chosen. Ag, Ca, Co, Cr, Mo and Sn were tested as internal standards. It has not been found any significant inter element effect. It is necessary to use natural fluorite as base material for the standards. (Author) 5 refs

  4. Bioaccessibility of micron-sized powder particles of molybdenum metal, iron metal, molybdenum oxides and ferromolybdenum--Importance of surface oxides.

    Science.gov (United States)

    Mörsdorf, Alexander; Odnevall Wallinder, Inger; Hedberg, Yolanda

    2015-08-01

    The European chemical framework REACH requires that hazards and risks posed by chemicals, including alloys and metals, that are manufactured, imported or used in different products (substances or articles) are identified and proven safe for humans and the environment. Metals and alloys need hence to be investigated on their extent of released metals (bioaccessibility) in biologically relevant environments. Read-across from available studies may be used for similar materials. This study investigates the release of molybdenum and iron from powder particles of molybdenum metal (Mo), a ferromolybdenum alloy (FeMo), an iron metal powder (Fe), MoO2, and MoO3 in different synthetic body fluids of pH ranging from 1.5 to 7.4 and of different composition. Spectroscopic tools and cyclic voltammetry have been employed to characterize surface oxides, microscopy, light scattering and nitrogen absorption for particle characterization, and atomic absorption spectroscopy to quantify released amounts of metals. The release of molybdenum from the Mo powder generally increased with pH and was influenced by the fluid composition. The mixed iron and molybdenum surface oxide of the FeMo powder acted as a barrier both at acidic and weakly alkaline conditions. These findings underline the importance of the surface oxide characteristics for the bioaccessibility of metal alloys. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  5. Determination of iron absorption and excretion by whole-body counting; Determination de l'absorption et de l'excretion du fer par la methode de comptage global humain

    Energy Technology Data Exchange (ETDEWEB)

    Hollard, D; Benabid, Y; Berard, M; Bonnin, J; Darnault, J; Millet, M [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    Using a whole-body counter, the authors have studied {sup 59}Fe absorption and loss in 8 normal subjects and in 30 iron deficient patients. Results showed that whole-body counting provided an excellent and simple method for iron retention measurements, obviating many inaccuracies of previous technic. Normal absorption of radio iron with this procedure has ranged from 9 per cent to 20 per cent of the administered tracer in normal subjects, with a mean of 15 per cent. A significant increase in {sup 59}Fe absorption was noted in 21 iron-deficient patients in whom the retention ranged from 40 to 100 per cent. However, 3 iron-deficient patients were found to have low absorption, and their severe iron deficiency could be correlated with this defect in absorption. This method permits also the determination of the rate of iron excretion during the following months and therefore the study of the mechanism of some pathological loss. (authors) [French] L'utilisation de la methode de comptage humain global a permis aux auteurs d'etudier l'absorption et l'excretion du fer-59 chez 8 sujets temoins et 30 sujets hyposideremiques. Les resultats montrent que cette technique simple et directe offre de nombreux avantages sur les methodes employees jusqu'a maintenant pour cette determination. La valeur normale de l'absorption du fer chez les temoins est d'environ 15 pour cent de la dose ingeree. Ce chiffre est tres fortement augmente chez 21 sujets hyposideremiques, pouvant atteindre 100 pour cent de la dose ingeree. Par contre, pour 3 malades, cette absorption est si faible qu'elle suggere une carence par defaut d'absorption. Cette methode permet egalement de suivre l'excretion du fer au cours des mois qui suivent l'examen et de determiner le mecanisme de fuites anormales. (auteurs)

  6. Preconcentration and determination of iron and copper in spice samples by cloud point extraction and flow injection flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Cigdem Arpa, E-mail: carpa@hacettepe.edu.tr [Hacettepe University, Chemistry Department, 06800 Beytepe, Ankara (Turkey); Tokgoez, Ilknur; Bektas, Sema [Hacettepe University, Chemistry Department, 06800 Beytepe, Ankara (Turkey)

    2010-09-15

    A flow injection (FI) cloud point extraction (CPE) method for the determination of iron and copper by flame atomic absorption spectrometer (FAAS) has been improved. The analytes were complexed with 3-amino-7-dimethylamino-2-methylphenazine (Neutral Red, NR) and octylphenoxypolyethoxyethanol (Triton X-114) was added as a surfactant. The micellar solution was heated above 50 {sup o}C and loaded through a column packed with cotton for phase separation. Then the surfactant-rich phase was eluted using 0.05 mol L{sup -1} H{sub 2}SO{sub 4} and the analytes were determined by FAAS. Chemical and flow variables influencing the instrumental and extraction conditions were optimized. Under optimized conditions for 25 mL of preconcentrated solution, the enrichment factors were 98 and 69, the limits of detection (3s) were 0.7 and 0.3 ng mL{sup -1}, the limits of quantification (10s) were 2.2 and 1.0 ng mL{sup -1} for iron and copper, respectively. The relative standard deviation (RSD) for ten replicate measurements of 10 ng mL{sup -1} iron and copper were 2.1% and 1.8%, respectively. The proposed method was successfully applied to determination of iron and copper in spice samples.

  7. One-shot flow injection spectrophotometric simultaneous determination of copper, iron and zinc in patients' sera with newly developed multi-compartment flow cell

    International Nuclear Information System (INIS)

    Teshima, Norio; Gotoh, Shingo; Ida, Kazunori; Sakai, Tadao

    2006-01-01

    We propose here an affordable flow injection method for simultaneous spectrophotometric determination of copper, iron and zinc in patients' sera. The use of a newly designed multi-compartment flow cell allowed the simultaneous determination of the three metals with a single injection ('one-shot') and a double beam spectrophotometer. The chemistry relied on the reactions of these metals with 2-(5-nitro-2-pyridylazo)-5-[N-propyl-N-(3-sulfopropyl)amino]phenol (nitro-PAPS) to form corresponding colored complexes. At pH 3.8, only copper-nitro-PAPS complex was formed in the presence of pyrophosphate as a masking agent for iron, and then the copper and iron(II) complexes were formed in the presence of reductant (ascorbic acid) at the same pH, and finally all three metals reacted with nitro-PAPS at pH 8.6. The characteristics were introduced into the flow system to determine each metal selectively and sensitively. Under the optimum conditions, linear calibration curves for the three metals were obtained in the range of 0.01-1 mg L -1 with a sample throughput rate of 20 h -1 . The limits of detection (3σ) were 3.9 μg L -1 for copper, 4.1 μg L -1 for iron and 4.0 μg L -1 for zinc. The proposed method was applied to analysis of some patients' sera

  8. Production of a carbon reducing agent and hydrogen by the thermocatalytic decomposition of hydrocarbons on the surface of iron

    Energy Technology Data Exchange (ETDEWEB)

    Borok, B A; Kel' tsev, V V

    1973-01-01

    In a series of laboratory experiments, natural gas containing 98.7% methane and 1.3% nitrogen was passed through a tube packed with particles of a reduced material containing 62% iron. At 900/sup 0/C and 25 vol/vol/hr space velocity, conversion was 99%, and the exit gas contained 98.4% hydrogen. The solid product, called sooty iron, obtained in the experiments contained 20 to 60% carbon; the volume of sponge iron treated with methane at 900/sup 0/C increased when the carbon content reached 30%. Runs with natural gas at a range of temperatures and constant space velocity or at 900/sup 0/C and increasing space velocity, runs with propane feed instead of methane, and the activity of the iron-carbon complex are discussed.

  9. Topography measurements for determining the decay factors in surface replication

    International Nuclear Information System (INIS)

    Song, J; Zheng, A; Vorburger, T V; Rubert, P

    2008-01-01

    The electro-forming technique is used at National Institute of Standards and Technology (NIST) for the production of standard reference material (SRM) 2461 standard casings to support nationwide ballistics measurement traceability and measurement quality control in the US. In order to ensure that the SRM casings are produced with virtually the same surface topography, it is necessary to test the decay factors of the replication process. Twenty-six replica casings are replicated from the same master casing for the decay factor tests. The NIST topography measurement system is used for measurements and correlations of surface topography. The topography decays are quantified by the cross-correlation function maximum CCF max . Based on the test, it is expected that 256 SRM casings can be replicated from the same master with CCF max values higher than 95%

  10. Adsorptive removal of arsenic by novel iron/olivine composite: Insights into preparation and adsorption process by response surface methodology and artificial neural network.

    Science.gov (United States)

    Ghosal, Partha S; Kattil, Krishna V; Yadav, Manoj K; Gupta, Ashok K

    2018-03-01

    Olivine, a low-cost natural material, impregnated with iron is introduced in the adsorptive removal of arsenic. A wet impregnation method and subsequent calcination were employed for the preparation of iron/olivine composite. The major preparation process parameter, viz., iron loading and calcination temperature were optimized through the response surface methodology coupled with a factorial design. A significant variation of adsorption capacity of arsenic (measured as total arsenic), i.e., 63.15 to 310.85 mg/kg for arsenite [As(III) T ] and 76.46 to 329.72 mg/kg for arsenate [As(V) T ] was observed, which exhibited the significant effect of the preparation process parameters on the adsorption potential. The iron loading delineated the optima at central points, whereas a monotonous decreasing trend of adsorption capacity for both the As(III) T and As(V) T was observed with the increasing calcination temperature. The variation of adsorption capacity with the increased iron loading is more at lower calcination temperature showing the interactive effect between the factors. The adsorbent prepared at the optimized condition of iron loading and calcination temperature, i.e., 10% and 200 °C, effectively removed the As(III) T and As(V) T by more than 96 and 99%, respectively. The material characterization of the adsorbent showed the formation of the iron compound in the olivine and increase in specific surface area to the tune of 10 multifold compared to the base material, which is conducive to the enhancement of the adsorption capacity. An artificial neural network was applied for the multivariate optimization of the adsorption process from the experimental data of the univariate optimization study and the optimized model showed low values of error functions and high R 2 values of more than 0.99 for As(III) T and As(V) T . The adsorption isotherm and kinetics followed Langmuir model and pseudo second order model, respectively demonstrating the chemisorption in this

  11. Electronegativity determination of individual surface atoms by atomic force microscopy

    Czech Academy of Sciences Publication Activity Database

    Onoda, J.; Ondráček, Martin; Jelínek, Pavel; Sugimoto, Y.

    2017-01-01

    Roč. 8, Apr (2017), 1-6, č. článku 15155. ISSN 2041-1723 R&D Projects: GA ČR(CZ) GC14-16963J Institutional support: RVO:68378271 Keywords : AFM * DFT * electronegativity * surface science Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 12.124, year: 2016

  12. The Arabidopsis MTP8 transporter determines the localization of manganese and iron in seeds

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Heng-Hsuan; Car, Suzana; Socha, Amanda L.; Hindt, Maria N.; Punshon, Tracy; Guerinot, Mary Lou

    2017-09-08

    Understanding how seeds obtain and store nutrients is key to developing crops with higher agronomic and nutritional value. We have uncovered unique patterns of micronutrient localization in seeds using synchrotron X-ray fluorescence (SXRF). Although all four members of the Arabidopsis thaliana Mn-CDF family can transport Mn, here we show that only mtp8-2 has an altered Mn distribution pattern in seeds. In an mtp8-2 mutant, Mn no longer accumulates in hypocotyl cortex cells and sub-epidermal cells of the embryonic cotyledons, but rather accumulates with Fe in the cells surrounding the vasculature, a pattern previously shown to be determined by the vacuolar transporter VIT1. We also show that MTP8, unlike the other three Mn-CDF family members, can transport Fe and is responsible for localization of Fe to the same cells that store Mn. When both the VIT1 and MTP8 transporters are non-functional, there is no accumulation of Fe or Mn in specific cell types; rather these elements are distributed amongst all cell types in the seed. Disruption of the putative Fe binding sites in MTP8 resulted in loss of ability to transport Fe but did not affect the ability to transport Mn.

  13. Manufacturing of Dysprosium-Iron Alloys by Electrolysis in Fluoride-Based Electrolytes: Oxide Solubility Determinations

    Science.gov (United States)

    Martinez, Ana Maria; Støre, Anne; Osen, Karen Sende

    2018-04-01

    Electrolytic production of light rare earth elements and alloys takes place in a fluoride-based electrolyte using rare earth oxides as raw material. The optimization of this method, mainly in terms of the energy efficiency and environmental impact control, is rather challenging. Anode effects, evolution of fluorine-containing compounds, and side cathode reactions could largely be minimized by a good control of the amount of rare earth oxide species dissolved in the fluoride-based electrolyte and their dissolution rate. The oxide content of the fluoride melts REF3-LiF (RE = Nd, Dy) at different compositions and temperatures were experimentally determined by carbothermal analysis of melt samples. The highest solubility values of oxide species, added as Dy2O3 and Dy2(CO3)3, were obtained to be of ca. 3 wt pct (expressed as Dy2O3) in the case of the equimolar DyF3-LiF melt at 1323 K (1050 °C). The oxide saturation values increased with the amount of REF3 present in the molten bath and the working temperature.

  14. A spectrofluorimetric sensor based on grape skin tissue for determination of iron(III

    Directory of Open Access Journals (Sweden)

    Minghui Zhang

    2010-04-01

    Full Text Available A spectrofluorimetric method based on the grape skin has been developed for the determination of Fe3+ at pH 5.0. The emission wavelength of the grape skin sensor occurs at 680 nm and the excitation wavelength at 421 nm. The fluorescence of sensor could be quenched by Fe3+ due to the complexing ability of anthocyanin with the metal ions. Anthocyanin, the main pigment in the grape skin, has been found fluorescence sensing material. The sensor based on the grape skin exhibited a calibration response for Fe3+ in two concentration ranges of 1.0 × 10-8 - 1.0 × 10-5 M (r2 = 0.9888 and 3.2 × 10-5 - 3.2 × 10-4 (r2 = 0.9856 M at 60 oC. The detection limit was found to be 7.5×10-9 M, and the other common ions did not interfere.

  15. Application of Volta potential mapping to determine metal surface defects

    International Nuclear Information System (INIS)

    Nazarov, A.; Thierry, D.

    2007-01-01

    As a rule, stress or fatigue cracks originate from various surface imperfections, such as pits, inclusions or locations showing a residual stress. It would be very helpful for material selection to be able to predict the likelihood of environment-assisted cracking or pitting corrosion. By using Scanning Kelvin Probe (the vibrating capacitor with a spatial resolution of 80 μm) the profiling of metal electron work function (Volta potential) in air is applied to the metal surfaces showing residual stress, MnS inclusions and wearing. The Volta potential is influenced by the energy of electrons at the Fermi level and drops generally across the metal/oxide/air interfaces. Inclusions (e.g. MnS) impair continuity of the passive film that locally decreases Volta potential. The stress applied gives rise to dislocations, microcracks and vacancies in the metal and the surface oxide. The defects decrease Volta and corrosion potentials; reduce the overvoltage for processes of passivity breakdown and anodic metal dissolution. These 'anodic' defects can be visualized in potential mapping that can help us to predict locations with higher risk of pitting corrosion or cracking

  16. Simultaneous radiochemical determination of plutonium, strontium, uranium, and iron nuclides and application to atmospheric deposition and aerosol samples

    Energy Technology Data Exchange (ETDEWEB)

    Rosner, G.; Hoetzl, H.; Winkler, R. (Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg (Germany, F.R.). Inst. fuer Strahlenschutz)

    1990-11-01

    A procedure for the sequential radiochemical determination of plutonium, strontium, uranium and iron nuclides is described. The separation is carried out on a single anion exchange column. Pu(IV), U(VI) and Fe(III) are fixed on Bio Rad AG 1-X4 from 9 mol/l HCl, while the sample effluent is used for the determination of radiostrontium. Fe and U are eluted separately with 7 mol/l HNO{sub 3}, and Pu(III) is eluted with 1.2 mol/l HCl containing hydrogen peroxide. Subsequently, Pu and U are electrolysed and counted by alpha spectrometry. Radiostrontium is purified by the nitrate method and counted in a low level beta proportional counter. Fe is purified by extraction and cation exchange and {sup 55}Fe is counted by X-ray spectrometry with a Si(Li) detector. The sample preparation and the application of the procedure to large samples, namely aerosols from 10{sup 5} m{sup 3} of air, and monthly deposition samples from 0.6 m{sup 2} sampling area (10-100 l) are described. Chemical yields are for Pu 70 {plus minus} 20, for Sr 80 {plus minus} 15, for U 80-90, and for Fe 75 {plus minus} 10%. As an example, the maximum airborne radionuclide concentrations determined with that procedure in fortnightly collected samples at Neuherberg after the Chernobyl accident were: {sup 239+240}Pu, 2.58; {sup 238}Pu, 1.40; {sup 238}U, 0.65; {sup 234}U, 0.67; {sup 90}Sr, 7600; and {sup 55}Fe, 990 {mu}Bqm{sup -3}. With appropriate changes in sample preparation, the procedure is applicable to other kinds of samples. (orig.).

  17. Simultaneous radiochemical determination of plutonium, strontium, uranium, and iron nuclides and application to atmospheric deposition and aerosol samples

    International Nuclear Information System (INIS)

    Rosner, G.; Hoetzl, H.; Winkler, R.

    1990-01-01

    A procedure for the sequential radiochemical determination of plutonium, strontium, uranium and iron nuclides is described. The separation is carried out on a single anion exchange column. Pu(IV), U(VI) and Fe(III) are fixed on Bio Rad AG 1-X4 from 9 mol/l HCl, while the sample effluent is used for the determination of radiostrontium. Fe and U are eluted separately with 7 mol/l HNO 3 , and Pu(III) is eluted with 1.2 mol/l HCl containing hydrogen peroxide. Subsequently, Pu and U are electrolysed and counted by alpha spectrometry. Radiostrontium is purified by the nitrate method and counted in a low level beta proportional counter. Fe is purified by extraction and cation exchange and 55 Fe is counted by X-ray spectrometry with a Si(Li) detector. The sample preparation and the application of the procedure to large samples, namely aerosols from 10 5 m 3 of air, and monthly deposition samples from 0.6 m 2 sampling area (10-100 l) are described. Chemical yields are for Pu 70 ± 20, for Sr 80 ± 15, for U 80-90, and for Fe 75 ± 10%. As an example, the maximum airborne radionuclide concentrations determined with that procedure in fortnightly collected samples at Neuherberg after the Chernobyl accident were: 239+240 Pu, 2.58; 238 Pu, 1.40; 238 U, 0.65; 234 U, 0.67; 90 Sr, 7600; and 55 Fe, 990 μBqm -3 . With appropriate changes in sample preparation, the procedure is applicable to other kinds of samples. (orig.)

  18. A pilot test of methods for determination of trace metals bound to colloids in surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Kersti (Geosigma AB (Sweden))

    2011-01-15

    Two methods have been tested for the determination of trace metals associated with colloid species in surface waters, using test water from Eckarfjaerden (PFM000070) in Forsmark; 1) fractionation (ultra filtration) using special membrane filters with cut-offs of 1 kD and 5 kD and 2) filtration using a system of standard membrane filters with varying pore sizes connected in series. Both methods were somewhat modified compared to previous methods for colloid determination in groundwater within the site investigations at Forsmark and Laxemar (PLU). The results show that, in general, the largest amounts of metals associated with a colloid phase were recovered in the fraction between 1kD and 5 kD which indicates that the metal ions are associated with low molecular weight organic acids. Similar amounts were recovered on the filters in the filtration experiment. A minor part of the colloidal phase metals was recovered in the fraction larger than 5 kD i.e. metal ions associated with larger organic acids or colloidal size clay minerals. The metals present preferably as colloids in the fractionation experiment were: iron, thorium, cerium, uranium, neodymium, titanium, zirconium and yttrium. The filtering experiment showed larger parts of titanium and aluminum in the colloid phase than the fractionation experiment while the iron and cerium portions were equal and the uranium, yttrium and neodymium portions were lower. The results from the fractionation test showed that the dissolved parts were large for barium, manganese, strontium and rubidium. In the filtration test, uranium, yttrium and rubidium, were also present mainly as dissolved ions. The detection limit for filter analysis of thorium was high, and the part of thorium present as colloids was determined to <50%. Issues and methodological problems: - Severe contamination caused interpretation difficulties for several metal ions, especially chromium, nickel and zinc. - Both methods are time consuming and difficult to

  19. Development of ELID mirror surface grinding by cast iron bond grinding wheel. Ohkochi memorial technology prize; Chutetsu bond toishi ni yoru denkai inpurosesu doresshingu (ELID) kyomen kensakuho no kaihatsu. Okochi kinen gijutsusho jusho ni yosete

    Energy Technology Data Exchange (ETDEWEB)

    Omori, H.; Takahashi, I. [Institute of Physical and Chemical Research, Tokyo (Japan); Nakagawa, T. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science; Hagiuda, Y.; Karikome, K. [Tokyo Metropolitan College of Aeronautical Engineering, Tokyo (Japan)

    1997-08-01

    Development was accomplished on the electrolytic in-process dressing (ELID) mirror surface grinding process using a cast iron bonded grinding wheel. This paper describes the history of the development, which may be summarized as follows: a study was begun on powder forging of cutting chips in 1970; a research was started on powder forging of decarburized cast iron powder; developments were made on powder metallurgy of cast irons and cast iron bonded lapping tools in 1980, and cast iron bonded diamond grinding wheels were put on the market; a high-efficiency grinding process using MC and cast iron fiber-bonded grinding wheels were developed in 1985 and the grinding wheels made therefrom were put on the market; and a study was begun on the ELID grinding in 1987, and marketing was started on power supply, grinding liquid and tools for the ELID grinding process in 1990. Discussions on converting raw materials for the powder forging into cutting chips have triggered developing the cast iron bonded grinding wheel. The cast iron bonded diamond grinding wheel improves dressability and sharpness of conventional grinding wheels. The grinding wheel is fabricated by mixing carbonyl iron powder, diamond grinding grains and cast iron powder, pressing the mixture in a die, sintering it at 1140 degC, and assembling and dressing the sinter. The grinding stone can grind high-tech materials. 4 figs.

  20. Determination of trace iron in the boiler water used in power generation plants by solid-phase spectrophotometry.

    Science.gov (United States)

    Sarenqiqige; Maeda, Akihiro; Yoshimura, Kazuhisa

    2014-01-01

    A sensitive, simple and low-cost determination method for the total iron concentration in boiler water systems of power generation plants was developed by solid phase spectrometry (SPS) using 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPTZ) as a coloring agent. The reagents and 0.08 cm(3) of a cation exchanger were added to a 50-cm(3) boiler water sample, then mixed for 30 min to adsorb/concentrate the produced Fe(TPTZ)2(2+) colored complex on the solid beads, resulting in a 625 times concentration of the target analyte without any other procedure. The detection limit of 0.1 μg dm(-3) was obtained, and the optimum conditions for the digestion procedure and color developing reaction was investigated and reported. According to the application of this method to real samples, the present SPS method is the best one because of the shorter analysis time, simpler operation and use of very low-cost equipment compared to the conventional methods, such as TPTZ solution spectrophotometric method after a 16 times concentration, ICP-MS and AAS.

  1. Flow-Injection Solid Phase Partial Least-Squares Spectrophotometric Simultaneous Determination of Iron, Nickel and Zinc

    Directory of Open Access Journals (Sweden)

    Teixeira Leonardo S. G.

    2002-01-01

    Full Text Available A PLS-2 multivariate calibration method has been developed for the simultaneous determination of iron, nickel and zinc in ternary mixtures by solid phase spectrophotometry associated with flow injection analysis. Fe(II, Ni(II and Zn(II form color complexes with 1-(2-thiazolylazo-2-naphthol (TAN, immobilized on a C18 bonded silica support, at pH 6.4. The proposed procedure is based on the different reaction/retention ratios of the studied ions on the solid support. Bilinear spectrophotometric data of the analytes, fixed in the solid support, were recorded in the 400-800 nm wavelength range as a function of time and a partial least squares (PLS-2 algorithm was used to predict results of synthetic samples. The calibration set employed was integrated by 8 ternary mixture standards and a blank solution. Mixtures containing 0.040 to 0.20 mg L-1, of each species, were successfully resolved, using 3 factors for each analyte and a restricted number of absorbance data obtained in the wavelength range from 560 to 650 nm.

  2. Effect of temperature during ion sputtering on the surface segregation rate of antimony in an iron-antimony alloy at higher temperatures

    International Nuclear Information System (INIS)

    Oku, M.; Hirokawa, K.; Kimura, H.; Suzuki, S.

    1986-01-01

    The surface segregation of antimony in an iron-0.23 at% antimony alloy was studied by XPS. The segregation rate in the temperature range between 800 and 900 K depends on the temperature during sputtering with argon ion of kinetic energy of 1 keV. The sputtering at room temperature or 473 K gives higher values of the segregation rate than those at 673 K. Both cases give the activation energy of 170 kJmol -1 for the surface segregation rate. The segregation of antimony is not observed after the sample is heated at 1000 K. (author)

  3. Towards advanced structural analysis of iron oxide clusters on the surface of γ-Al{sub 2}O{sub 3} using EXAFS

    Energy Technology Data Exchange (ETDEWEB)

    Boubnov, Alexey [Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131 Karlsruhe (Germany); Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Roppertz, Andreas [Institute of Energy Process Engineering and Chemical Engineering, Chair of Reaction Engineering, Technical University of Freiberg, Fuchsmuehlenweg 9, D-09599 Freiberg (Germany); Kundrat, Matthew D. [Center for Functional Nanostructures and Institute of Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131 Karlsruhe (Germany); Mangold, Stefan [Institut für Beschleunigerphysik und Technologie (IBPT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Reznik, Boris [Institute of Applied Geosciences, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131 Karlsruhe (Germany); Jacob, Christoph R. [Center for Functional Nanostructures and Institute of Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131 Karlsruhe (Germany); Institute of Physical and Theoretical Chemistry, TU Braunschweig, Hans-Sommer-Str. 10, D-38106 Braunschweig (Germany); Kureti, Sven [Institute of Energy Process Engineering and Chemical Engineering, Chair of Reaction Engineering, Technical University of Freiberg, Fuchsmuehlenweg 9, D-09599 Freiberg (Germany); Grunwaldt, Jan-Dierk, E-mail: grunwaldt@kit.edu [Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131 Karlsruhe (Germany); Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2016-11-15

    Highlights: • Analysis of isolated and oligomeric FeOx (x = 4, 5) on Al{sub 2}O{sub 3} by XANES and EXAFS. • Iron is trivalent and is mainly located at octahedral lattice sites of Al{sub 2}O{sub 3}. • Low Fe loading (0.1%) guarantees high dispersion of catalytically active iron sites. • Surface Fe-cluster on Al{sub 2}O{sub 3} and DFT-optimised Fe-doped Al{sub 2}O{sub 3} as input models for EXAFS. • Interactions of iron with support are well-accounted for using realistic models. - Abstract: Iron oxide centres are structurally investigated in 0.1% Fe/γ-Al{sub 2}O{sub 3}, which is known as highly active catalyst, for instance in the oxidation of CO. The sample was characterised by using X-ray absorption spectroscopy (XAS) in terms of X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), Mössbauer spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). These analyses evidenced high dispersion of the iron oxide entities without significant presence of bulk-like aggregates associated with the low Fe content of the catalyst. A library of structural models of Al{sub 2}O{sub 3}-supported surface Fe was created as input for EXAFS fitting. Additionally, several model structures of Fe substituting Al ions in bulk γ-Al{sub 2}O{sub 3} were created with optimised geometry based on density-functional theory (DFT) calculations. From EXAFS refinement of the best 8 out of 24 models, it was found that the trivalent Fe ions are coordinated by 4–5 oxygen atoms and are located on octahedral lattice sites of the exposed surfaces of γ-Al{sub 2}O{sub 3}. These iron oxide species exist mainly as a mixture of monomeric and binuclear species and due to the low concentration represent suitable model systems as alternative to single crystal systems for structure-function relationships.

  4. The effects of novel surface treatments on the wear and fatigue properties of steel and chilled cast iron

    Science.gov (United States)

    Carroll, Jason William

    Contact fatigue driven wear is a principal design concern for gear and camshaft engineering of power systems. To better understand how to engineer contact fatigue resistant surfaces, the effects of electroless nickel and hydrogenated diamond-like-carbon (DLC) coatings on the fatigue life at 108 cycles of SAE 52100 steel were studied using ultrasonic fatigue methods. The addition of DLC and electroless nickel coatings to SAE 52100 bearing steel had no effect on the fatigue life. Different inclusion types were found to affect the stress intensity value beyond just the inclusion size, as theorized by Murakami. The difference in stress intensity values necessary to propagate a crack for Ti (C,N) and alumina inclusions was due to the higher driving force for crack extension at the Ti (C,N) inclusions and was attributed to differences in the shape of the inclusion: rhombohedral for the Ti (C,N) versus spherical for the oxides. A correction factor was added to the Murakami equation to account for inclusion type. The wear properties of DLC coated SAE 52100 and chilled cast iron were studied using pin-on-disk tribometry and very high cycle ultrasonic tribometry. A wear model that includes sliding thermal effects as well as thermodynamics consistent with the wear mechanism for DLCs was developed based on empirical results from ultrasonic wear testing to 108 cycles. The model fit both ultrasonic and classic tribometer data for wear of DLCs. Finally, the wear properties of laser hardened steels - SAE 8620, 4140, and 52100 - were studied at high contact pressures and low numbers of cycles. A design of experiments was conducted to understand how the laser processing parameters of power, speed, and beam size, as well as carbon content of the steel, affected surface hardness. A hardness maximum was found at approximately 0.7 wt% carbon most likely resulting from increased amounts of retained austenite. The ratcheting contact fatigue model of Kapoor was found to be useful in

  5. Determination of near surface in-situ stresses

    International Nuclear Information System (INIS)

    Garritty, P.; Irvin, R.

    1983-06-01

    One of the major unknowns affecting aspects of underground construction and the geohydrology of rock masses is the magnitude and direction of the geostatic principal stresses in the earth's crust. This is particularly the case in near surface rocks where there are indications that high horizontal stresses may exist. The techniques, experiences and results of a preliminary rock stress measurement programme conducted at shallow depth in the Carnmenellis Granite, Cornwall, using C.S.I.R.O. triaxial hollow inclusion cells are described. (author)

  6. Studies on the pathogenesis in iron deficiency anemia Part 1. Urinary iron excretion in iron deficiency anemia patients and rats in various iron states

    OpenAIRE

    中西,徳彦

    1991-01-01

    In the "iron excretion test" , urinary iron excretion after injection of saccharated iron oxide has been reported to be accelerated in relapsing idiopathic iron deficiency anemia. To determine the relevance of urinary iron excretion to clinical factors other than iron metabolism, 15 clinical parameters were evaluated. The serum creatinine level was positively and the serum albumin level was negatively correlated with urinary iron excretion, showing coefficients of r=0.97,-0.86 respectively, a...

  7. Induction Thermography for Surface Crack Detection and Depth Determination

    Directory of Open Access Journals (Sweden)

    Beate Oswald-Tranta

    2018-02-01

    Full Text Available In the last few years, induction thermography has been established as a non-destructive testing method for localizing surface cracks in metals. The sample to be inspected is heated with a short induced electrical current pulse, and the infrared camera records—during and after the heating pulse—the temperature distribution at the surface. Transforming the temporal temperature development for each pixel to phase information makes not only highly reliable detection of the cracks possible but also allows an estimation of its depth. Finite element simulations were carried out to investigate how the phase contrast depends on parameters such as excitation frequency, pulse duration, material parameters, crack depth, and inclination angle of the crack. From these results, generalized functions for the dependency of the phase difference on all these parameters were derived. These functions can be used as an excellent guideline as to how measurement parameters should be optimized for a given material to be able to detect cracks and estimate their depth. Several experiments on different samples were also carried out, and the results compared with the simulations showed very good agreement.

  8. Determination of lanthanum and rare earth elements in bovine whole blood reference material by ICP-MS after coprecipitation preconcentration with heme-iron as coprecipitant

    International Nuclear Information System (INIS)

    Fujimori, Eiji; Hayashi, Tatsuya; Inagaki, Kazumi; Haraguchi, H.

    1999-01-01

    An analytical method for the determination of lanthanide elements in the bovine whole blood reference material (IAEA A-13) has been investigated by inductively coupled plasma mass spectrometry (ICP-MS). The bovine whole blood reference material was digested with HNO 3 and HClO 4 , and then the pH of the digested solution was adjusted to 12 with 3 M sodium hydroxide aqueous solution. In this experimental procedure, lanthanide elements in the blood sample were coprecipitated with iron mainly derived from heme-iron in blood itself. In order to minimize matrix effects due to iron, excess iron in the analysis solution was removed by solvent extraction using methyl isobutyl ketone (MIBK) prior to the determination of lanthanide elements by ICP-MS. The recoveries of all lanthanide elements were almost quantitative in the recovery test. In consequence, it has been found that all lanthanide elements in bovine whole blood reference material are at the wide concentration range of 0.90 pg/g for Tm ∝1880 pg/g for Ce. (orig.)

  9. A Solid Binding Matrix/Mimic Receptor-Based Sensor System for Trace Level Determination of Iron Using Potential Measurements

    OpenAIRE

    Kamel, Ayman H.; Moreira, Felismina T. C.; Silva, Tamara I.; Sales, M. Goreti F.

    2011-01-01

    Iron(II)-(1,10-phenanthroline) complex imprinted membrane was prepared by ionic imprinting technology. In the first step, Fe(II) established a coordination linkage with 1,10-phenanthroline and functional monomer 2-vinylpyridine (2-VP). Next, the complex was copolymerized with ethylene glycol dimethacrylate (EGDMA) as a crosslinker in the presence of benzoyl peroxide (BPO) as an initiator. Potentiometric chemical sensors were designed by dispersing the iron(II)-imprinted polymer particles in 2...

  10. The role of iron in tetrahedrite and tennantite determined by Rietveld refinement of neutron powder diffraction data

    DEFF Research Database (Denmark)

    Andreasen, Jens Wenzel; Makovicky, Emil; Lebech, Bente

    2008-01-01

    Rietveld refinement of neutron powder diffraction data on four samples of synthetic, iron-bearing tetrahedrite (Cu12-xFexSb4S13) with x = 0.28, 0.69, 0.91, 2.19 and four samples of synthetic tennantite (Cu12-xFexAs4S13) with x = 0.33, 0.38, 0.86, 1.5 indicate unambiguously that iron is incorporated...

  11. Surface structure determinations of crystalline ionic thin films grown on transition metal single crystal surfaces by low energy electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Joel Glenn [Univ. of California, Berkeley, CA (United States)

    2000-05-01

    The surface structures of NaCl(100), LiF(100) and alpha-MgCl2(0001) adsorbed on various metal single crystals have been determined by low energy electron diffraction (LEED). Thin films of these salts were grown on metal substrates by exposing the heated metal surface to a molecular flux of salt emitted from a Knudsen cell. This method of investigating thin films of insulators (ionic salts) on a conducting substrate (metal) circumvents surface charging problems that plagued bulk studies, thereby allowing the use of electron-based techniques to characterize the surface.

  12. Permeable reactive barrier of surface hydrophobic granular activated carbon coupled with elemental iron for the removal of 2,4-dichlorophenol in water

    Energy Technology Data Exchange (ETDEWEB)

    Yang Ji, E-mail: yangji@ecust.edu.cn [School of Resources and Environmental Engineering, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237 (China); Cao Limei; Guo Rui; Jia Jinping [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2010-12-15

    Granular activated carbon was modified with dimethyl dichlorosilane to improve its surface hydrophobicity, and therefore to improve the performance of permeable reactive barrier constructed with the modified granular activated carbon and elemental iron. X-ray photoelectron spectroscopy shows that the surface silicon concentration of the modified granular activated carbon is higher than that of the original one, leading to the increased surface hydrophobicity. Although the specific surface area decreased from 895 to 835 m{sup 2} g{sup -1}, the modified granular activated carbon could adsorb 20% more 2,4-dichlorophenol than the original one did in water. It is also proven that the permeable reactive barrier with the modified granular activated carbon is more efficient at 2,4-dichlorophenol dechlorination, in which process 2,4-dichlorophenol is transformed to 2-chlorophenol or 4-chlorophenol then to phenol, or to phenol directly.

  13. Permeable reactive barrier of surface hydrophobic granular activated carbon coupled with elemental iron for the removal of 2,4-dichlorophenol in water

    International Nuclear Information System (INIS)

    Yang Ji; Cao Limei; Guo Rui; Jia Jinping

    2010-01-01

    Granular activated carbon was modified with dimethyl dichlorosilane to improve its surface hydrophobicity, and therefore to improve the performance of permeable reactive barrier constructed with the modified granular activated carbon and elemental iron. X-ray photoelectron spectroscopy shows that the surface silicon concentration of the modified granular activated carbon is higher than that of the original one, leading to the increased surface hydrophobicity. Although the specific surface area decreased from 895 to 835 m 2 g -1 , the modified granular activated carbon could adsorb 20% more 2,4-dichlorophenol than the original one did in water. It is also proven that the permeable reactive barrier with the modified granular activated carbon is more efficient at 2,4-dichlorophenol dechlorination, in which process 2,4-dichlorophenol is transformed to 2-chlorophenol or 4-chlorophenol then to phenol, or to phenol directly.

  14. Permeable reactive barrier of surface hydrophobic granular activated carbon coupled with elemental iron for the removal of 2,4-dichlorophenol in water.

    Science.gov (United States)

    Yang, Ji; Cao, Limei; Guo, Rui; Jia, Jinping

    2010-12-15

    Granular activated carbon was modified with dimethyl dichlorosilane to improve its surface hydrophobicity, and therefore to improve the performance of permeable reactive barrier constructed with the modified granular activated carbon and elemental iron. X-ray photoelectron spectroscopy shows that the surface silicon concentration of the modified granular activated carbon is higher than that of the original one, leading to the increased surface hydrophobicity. Although the specific surface area decreased from 895 to 835 m(2)g(-1), the modified granular activated carbon could adsorb 20% more 2,4-dichlorophenol than the original one did in water. It is also proven that the permeable reactive barrier with the modified granular activated carbon is more efficient at 2,4-dichlorophenol dechlorination, in which process 2,4-dichlorophenol is transformed to 2-chlorophenol or 4-chlorophenol then to phenol, or to phenol directly. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Determination of suitable chemical extraction methods for the available iron content of brown forest soils in Turkey

    Science.gov (United States)

    Adiloglu, Aydin

    2006-09-01

    The aim of this research was to determine the available iron (Fe) content of brown forest soils of Edirne Province and the most suitable chemical extraction method. Eight chemical extraction methods (the 0.005 M DTPA + 0.01 M CaCl2 + 0.1 MTEA, 0.05 M HCl + 0.012 M H2SO4, 1 M NH4OAc (pH: 4.8), 0.01 M EDTA + 1 M NH4OAc, 1 M MgCl2, 0.01 M EDTA + 1 M (NH4)2CO3, 0.005 M DTPA + 1 M NH4HCO3, and 0.001 M EDDHA methods) and six biological indices (the dry matter yield, Fe concentration, Fe uptake, relative dry matter yield, relative Fe concentration, and relative Fe uptake) were compared. The biological indices were determined with barley (Hordeum vulgare L.) grown under greenhouse conditions. At the end of the experiment, the highest correlation coefficients (r) were determined to be between the 0.005 M DTPA + 0.01 M CaCl2 + 0.1 M TEA method and the biological indices and between the 0.005 M DTPA + 1 M NH4HCO3 method and the biological indices. The corresponding correlation coefficients (r) for the 0.005 M DTPA + 0.01 M CaCl2 + 0.1 M TEA method and the six biological indices were 0.621**, 0.823**, 0.810** 0.433**, 0.558**, and 0.640**, respectively. For the 0.005 M DTPA + 1 M NH4HCO3 method, these coefficients were equal to 0.618**, 0.520**, 0.679**, 0.521**, 0.492**, and 0.641**, respectively (** indicate the validity of the relationships at p < 0.01) These extraction methods, out of all the methods tested, were suggested for the determination of the available Fe content of the brown forest soils.

  16. Carbon steel protection in G.S. (Girlder sulfide) plants. Iron sulfide scales formation on surfaces covered by fabrication produced films. Pt. 4

    International Nuclear Information System (INIS)

    Burkart, A.L.

    1986-04-01

    This work describes the assays aimed to passivate the steel carbon of the process pipings. This steel is marked by the ASTM A 333 G6 and is chemically similar to those of isotopic exchange towers which corrode in contact with in-water hydrogen sulfide solutions forming iron sulfide protective layers. The differences between both materials lie in the surface characteristics to be passivated. The steel of towers has an internal side covered by paint which shall be removed prior to passivation. The steel's internal side shall be covered by a film formed during the fabrication process and constituted by calcinated wastes and iron oxides (magnetite, hematite and wustite). This film interferes in the formation process of passivating layers of pyrrhotite and pyrite. The possibility to passivate the pipes in their actual state was evaluated since it would result highly laborious and expensive to eliminate the film. (Author) [es

  17. Influence of the reagent concentration of the colorimetric copper determination with sodium diethyl dithiocarbamate (abbreviated: D.D.C.) and its importance for the determination of copper in the presence of large amounts of iron

    NARCIS (Netherlands)

    Karsten, P.; Rademaker, S.C.; Walraven, J.J.

    1950-01-01

    From a research about the influence of the reagent concentration on the copper determination with sodium di-ethyl-di-thio-carbamate in the presence of large amounts of iron some insight was gained into factors which had never been examined so far and which were found to have great influence on the

  18. Background electrolytes and pH effects on selenate adsorption using iron-impregnated granular activated carbon and surface binding mechanisms.

    Science.gov (United States)

    Zhang, Ning; Gang, Daniel Dianchen; McDonald, Louis; Lin, Lian-Shin

    2018-03-01

    Iron-impregnated granular activated carbon (Fe-GAC) has been shown effective for selenite adsorptive removal from aqueous solutions, but similar effectiveness was not observed with selenate. This study examined the effects of background electrolytes and pH on selenate adsorption on to Fe-GAC, and surface bindings to elucidate the selenate adsorption mechanisms. The decrease magnitude of selenate adsorption capacity under three background electrolytes followed the order: LiCl > NaCl > KCl, as ionic strength increased from 0.01 to 0.1 M. Larger adsorption capacity differences among the three electrolytes were observed under the higher ionic strengths (0.05 and 0.1 M) than those under 0.01 M. Multiplet peak fittings of high resolution X-ray photoelectron spectra for O1s and Fe2p 3/2 indicated the presence of iron (III) on adsorbent surface. pH variations during the adsorbent preparation within 3-8 in NaCl solutions did not cause appreciable changes in the iron redox state and composition. Raman spectra showed the formation of both monodentate and bidentate inner sphere complexes under pHs adsorption under alkaline conditions. Mechanisms for monodentate and bidentate formations and a stable six-member ring structure were proposed. Two strategies were recommended for modifying Fe-GAC preparation procedure to enhance the selenate adsorption: (1) mixed-metal oxide coatings to increase the point of zero charge (pH zpc ); and (2) ferrous iron coating to initially reduce selenate followed by selenite adsorption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Photochemical decoration of gold nanoparticles on polymer stabilized magnetic microspheres for determination of adenine by surface-enhanced Raman spectroscopy

    International Nuclear Information System (INIS)

    Alula, Melisew Tadele; Yang, Jyisy

    2015-01-01

    Magnetic microspheres decorated with gold nanoparticles (AuNPs) were prepared and used for the determination of adenine by surface-enhanced Raman scattering (SERS). Magnetic particles were first synthesized by coprecipitation of solutions containing iron(II) and iron(III) ions with ammonium hydroxide. Subsequently, the magnetic particles were suspended into a solution of poly(divinylbenzene-co-methyl methacrylate) to yield polymer-stabilized magnetic microspheres. These were further decorated with AuNPs via a new photochemical reduction method. The magnetic microspheres were characterized by XRD patterns and SEM images. They are shown to represent highly SERS-active substrates by giving an enhancement by almost 7 orders of magnitude compared to conventional Raman spectroscopy. Several factors that affect the photochemical reduction to form the AuNPs were examined. It is found that the concentration of gold ion, UV irradiation time, and citrate concentration have more impact on the reaction rate than on the morphologies of the AuNPs. The gold-decorated magnetic microspheres are highly stable in aqueous solution and capable of concentrating nucleobases. A linear response of the SERS signal to adenine in concentrations up to 10 μM is found, with a linear regression coefficient of 0.997. The detection limit is estimated to a few hundreds of nM (at an SNR of 3). Based on its specific Raman peak at 734 cm −1 , adenine can be selectively determined without interference by other nucleobases, and a recovery higher than 95 % could be obtained. (author)

  20. A study on surface properties and high temperature oxidation behavior of ion nitrided FC-25 gray cast iron

    International Nuclear Information System (INIS)

    Hur, In Chang; Son, Kun Su; Yoon, Jae Hong; Cho, Tong Yul; Park, Bong Gyu; Kim, Hyun Soo; Kim, In Soo

    2005-01-01

    Surface properties and high temperature oxidation behavior were investigated for FC-25 Gray Cast Iron(GCI) and the ion intrided GCI(N-GCI). The GCI was pre-cleaned to improve hardness to the optimum pre-sputtering parameters with an Ar/H 2 ratio of 1/2, working pressure of 3 torr, working temperature of 550 .deg. C and working time of 1hour. The optimum nitriding conditions for the maximum hardness of 560∼575 Hv were an N 2 /H 2 ratio of 3/1, working pressure of 3 torr, and working temperature of 575 deg. C. The thickness of graphite in the GCI was increased by increasing the working temperature from 525 .deg. C to 595 .deg. C for the nitriding time of 6∼18hrs. XRD patterns showed FeO and Fe 2 O 3 peaks for both the oxidized N-GCI and GCI at temperature of 600 .deg. C and 800 .deg. C under atmospheric environment for both 24 and 60hours. At 800 .deg. C, above the Fe 4 N decomposition temperature of 680 .deg. C, the oxidation rate of N-GCI was greater than that of the GCI. The most abundant nitride, Fe 4 N, was decomposed and the nitrogen gas given off by the decomposition made the protective film porous by degassing through the film. But at 600 .deg. C, below the decomposition temperature, the degree of oxidation of N-GCI was lower than that of the GCI because the nitride film worked as protective barrier for oxidation. Finite element modeling of elastic contact wear problems was performed to demonstrate the feasibility of applying the finite element method to fretting wear problems. The elastic beam problem, with existing solutions, is treated as a numerical example. By introducing a control parameter s, which scaled up the wear constant and scaled down the cycle numbers, the algorithm was shown to greatly reduce the time required for the analysis. The work rate model was adopted in the wear model. In the three-dimensional finite element analysis, a quarterly symmetric model was used to simulate cross tubes contacting at right angles. The wear constant of

  1. Neutron activation analysis application for determining iron concentration in forage grasses used in intensive cattle production system

    International Nuclear Information System (INIS)

    Armelin, Maria Jose A.; Primavesi, Odo

    2002-01-01

    Iron is an essential element to the life. It is an important hemoglobin component and it is involved in the transport of oxygen to cells. A deficiency of iron results in an unsuitable synthesis of hemoglobin and a delay in the growth. Iron contents above the tolerable level in animal feed can cause serious damages to the health and the death in extreme cases. The forages are the main source of feed to cattle in grazing. It is known from the literature, that the growth and the nutritious value of the forage are influenced by specie and physiologic age of the plant, soil fertility and environmental conditions. Therefore, an agronomical evaluations of the forages are necessary before to introduce in an intensive cattle production systems to program adequate grazing management. Neutron activation analysis was applied to evaluate the Fe concentration in the main tropical forage grasses used in intensive dairy cattle production systems in Sao Carlos, SP, Brazil. Iron concentrations were smaller in the rain season than in the dry one. Comparison of results obtained in the analyses of forages with daily requirements of iron in dry matter, showed that the Fe concentration in forages was adequate. (author)

  2. Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids - Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method

    International Nuclear Information System (INIS)

    2004-01-01

    This first edition of ISO 7097-1 together with ISO 7097-2:2004 cancels and replaces ISO 7097:1983, which has been technically revised, and ISO 9989:1996. ISO 7097 consists of the following parts, under the general title Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids: Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method; Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This part 2. of ISO 7097 describes procedures for determination of uranium in solutions, uranium hexafluoride and solids. The procedures described in the two independent parts of this International Standard are similar: this part uses a titration with cerium(IV) and ISO 7097-1 uses a titration with potassium dichromate

  3. Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids - Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method

    International Nuclear Information System (INIS)

    2004-01-01

    This first edition of ISO 7097-1 together with ISO 7097-2:2004 cancels and replaces ISO 7097:1983, which has been technically revised, and ISO 9989:1996. ISO 7097 consists of the following parts, under the general title Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids: Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method; Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This part 1. of ISO 7097 describes procedures for the determination of uranium in solutions, uranium hexafluoride and solids. The procedures described in the two independent parts of this International Standard are similar: this part uses a titration with potassium dichromate and ISO 7097-2 uses a titration with cerium(IV)

  4. Rate of Iron Transfer Through the Horse Spleen Ferritin Shell Determined by the Rate of Formation of Prussian Blue and Fe-desferrioxamine Within the Ferritin Cavity

    Science.gov (United States)

    Zhang, Bo; Watt, Richard K.; Galvez, Natividad; Dominquez-Vera, Jose M.; Watt, Gerald D.

    2005-01-01

    Iron (2+ and 3+) is believed to transfer through the three-fold channels in the ferritin shell during iron deposition and release in animal ferritins. However, the rate of iron transit in and out through these channels has not been reported. The recent synthesis of [Fe(CN)(sub 6)](3-), Prussian Blue (PB) and desferrioxamine (DES) all trapped within the horse spleen ferritin (HoSF) interior makes these measurements feasible. We report the rate of Fe(2+) penetrating into the ferritin interior by adding external Fe(2+) to [Fe(CN)(sub 6)](3-) encapsulated in the HoSF interior and measuring the rate of formation of the resulting encapsulated PB. The rate at which Fe(2+) reacts with [Fe(CN)(sub 6)](3-) in the HoSF interior is much slower than the formation of free PB in solution and is proceeded by a lag period. We assume this lag period and the difference in rate represent the transfer of Fe(2+) through the HoSF protein shell. The calculated diffusion coefficient, D approx. 5.8 x 10(exp -20) square meters per second corresponds to the measured lag time of 10-20 s before PB forms within the HoSF interior. The activation energy for Fe(2+) transfer from the outside solution through the protein shell was determined to be 52.9 kJ/mol by conducting the reactions at 10 to approximately 40 C. The reaction of Fe(3+) with encapsulated [Fe(CN)6](4-) also readily forms PB in the HoSF interior, but the rate is faster than the corresponding Fe(2+) reaction. The rate for Fe(3+) transfer through the ferritin shell was confirmed by measuring the rate of the formation of Fe-DES inside HoSF and an activation energy of 58.4 kJ/mol was determined. An attempt was made to determine the rate of iron (2+ and 3+) transit out from the ferritin interior by adding excess bipyridine or DES to PB trapped within the HoSF interior. However, the reactions are slow and occur at almost identical rates for free and HoSF-encapsulated PB, indicating that the transfer of iron from the interior through the

  5. Patterns of motor recruitment can be determined using surface EMG.

    Science.gov (United States)

    Wakeling, James M

    2009-04-01

    Previous studies have reported how different populations of motor units (MUs) can be recruited during dynamic and locomotor tasks. It was hypothesised that the higher-threshold units would contribute higher-frequency components to the sEMG spectra due to their faster conduction velocities, and thus recruitment patterns that increase the proportion of high-threshold units active would lead to higher-frequency elements in the sEMG spectra. This idea was tested by using a model of varying recruitment coupled to a three-layer volume conductor model to generate a series of sEMG signals. The recruitment varied from (A) orderly recruitment where the lowest-threshold MUs were initially activated and higher-threshold MUs were sequentially recruited as the contraction progressed, (B) a recurrent inhibition model that started with orderly recruitment, but as the higher-threshold units were activated they inhibited the lower-threshold MUs (C) nine models with intermediate properties that were graded between these two extremes. The sEMG was processed using wavelet analysis and the spectral properties quantified by their mean frequency, and an angle theta that was determined from the principal components of the spectra. Recruitment strategies that resulted in a greater proportion of faster MUs being active had a significantly lower theta and higher mean frequency.

  6. Effect of heat treatment in air on surface composition of iron-phosphate based soft magnetic composite components

    Energy Technology Data Exchange (ETDEWEB)

    Oikonomou, C., E-mail: christos.oikonomou@chalmers.se; Oro, R.; Hryha, E.; Nyborg, L.

    2014-11-15

    Highlights: • Surface morphological and chemical depth profiling analyses of SMC parts. • Effect of annealing at exterior/interior areas for different temperature regimes. • Difference in degree of oxidation/nature of bulk/coating with area and temperature. • Thermodynamic calculations/considerations on the thermal stability of the coating. • Incomplete delubrication and strong bulk oxidation of the samples under 500 °C. - Abstract: Soft magnetic composite materials (SMC) manufactured by conventional powder metallurgical techniques for electromagnetic applications constitute individually encapsulated ferromagnetic powder particles with an insulating surface layer, bonded together into 3D finished structures. The production procedure includes compaction of the SMC base powder mixed with a lubricant substance and a post-annealing treatment that aims to relieve the stresses induced in the component during pressing. In the present study, the effect of the heat treatment process to the nature of the insulating layer was investigated under different temperature regimes using analytical techniques. Its surface chemistry was determined based on the XPS depth profiling technique, and its morphology and structure were evaluated using HR-SEM and XRD. Differences between interior and exterior areas of the samples suggested the development of an oxide scale in the outer regions that prevents its further bulk oxidation at temperatures above 500 °C, while below that temperature incomplete de-lubrication takes place.

  7. Spectrophotometric Determination of Iron(II and Cobalt(II by Direct, Derivative, and Simultaneous Methods Using 2-Hydroxy-1-Naphthaldehyde-p-Hydroxybenzoichydrazone

    Directory of Open Access Journals (Sweden)

    V. S. Anusuya Devi

    2012-01-01

    Full Text Available Optimized and validated spectrophotometric methods have been proposed for the determination of iron and cobalt individually and simultaneously. 2-hydroxy-1-naphthaldehyde-p-hydroxybenzoichydrazone (HNAHBH reacts with iron(II and cobalt(II to form reddish-brown and yellow-coloured [Fe(II-HNAHBH] and [Co(II-HNAHBH] complexes, respectively. The maximum absorbance of these complexes was found at 405 nm and 425 nm, respectively. For [Fe(II-HNAHBH], Beer’s law is obeyed over the concentration range of 0.055–1.373 μg mL−1 with a detection limit of 0.095 μg mL−1 and molar absorptivity ɛ, 5.6 × 104 L mol−1 cm−1. [Co(II-HNAHBH] complex obeys Beer’s law in 0.118–3.534 μg mL−1 range with a detection limit of 0.04 μg mL−1 and molar absorptivity, ɛ of 2.3 × 104 L mol−1 cm−1. Highly sensitive and selective first-, second- and third-order derivative methods are described for the determination of iron and cobalt. A simultaneous second-order derivative spectrophotometric method is proposed for the determination of these metals. All the proposed methods are successfully employed in the analysis of various biological, water, and alloy samples for the determination of iron and cobalt content.

  8. Elimination of the inter-element interferences of iron, gold, molybdenum, tin and antimony when determined in organic solvents by flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Aneva, Zara; Arpadjan, Sonja

    1988-01-01

    The mutual interferences in the flame atomic absorption spectrometric determination of iron, gold, molybdenum, tin and antimony after their extraction - pre-concentration as chloride complexes from platinum solutions into isobutyl methyl ketone are investigated. It is suggested that the interferences are caused by chemical reactions in the flame and are influenced by the flame characteristics. The possibility of eliminating the interferences by addition of long-chain quaternary ammonium salts is discussed. (author)

  9. Benefits of siderophore release lie in mediating diffusion limitation at low iron solubility

    OpenAIRE

    Leventhal, Gabriel; Schiessl, Konstanze; Ackermann, Martin

    2016-01-01

    Siderophores are chelators released by many bacteria to take up iron. In contrast to iron receptors located at the cell surface, released siderophores are at risk of being lost to environmental sinks. Here, we asked the question whether the release itself is essential for the function of siderophores, which could explain why such a risky strategy is widespread. We developed a reaction-diffusion model to determine the impact of siderophore release on overcoming iron limitation caused by poor s...

  10. Influence of different synthesis approach on doping behavior of silver nanoparticles onto the iron oxide-silica coreshell surfaces

    Czech Academy of Sciences Publication Activity Database

    Mahmed, N.; Jiang, H.; Heczko, Oleg; Söderberg, O.; Hannula, S.-P.

    2012-01-01

    Roč. 14, č. 8 (2012), s. 1-15 ISSN 1388-076