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Sample records for hard material ruthenium

  1. Emergent property of high hardness for C-rich ruthenium carbides: partial covalent Ru-Ru bonds.

    Science.gov (United States)

    Xu, Chunhong; Yu, Hongyu; Kuo, Bao; Ma, Shuailing; Xiao, Xuehui; Li, Da; Duan, Defang; Jin, Xilian; Liu, Bingbing; Cui, Tian

    2018-02-14

    Hard materials are being investigated all the time by combining transition metals with light elements. Combining a structure search with first-principles functional calculations, we first discovered three stable stoichiometric C-rich ruthenium carbides in view of three synthesis routes, namely, the ambient phases of Ru 2 C 3 and RuC, and two high pressure phases of RuC 4 . There is a phase transition of RuC 4 from the P3[combining macron]m1 structure to the R3[combining macron]m structure above 98 GPa. The calculations of elastic constants and phonon dispersions show their mechanical and dynamical stability. The large elastic modulus, high Debye temperature and the estimated hardness values suggest that these hard ruthenium carbides have good mechanical properties. The analyses of electronic structure and chemical bonding indicate that chemical bonding, not carbon content, is the key factor for the hardness in these metallic C-rich ruthenium carbides. The partial covalent Ru-C bonds and strong covalent C-C bonds are responsible for the high hardness. Moreover, the emergence of partial covalent Ru-Ru bonds can enhance the hardness of RuC, while the ionic Ru-Ru bonds can weaken the hardness of Ru 2 C 3 .

  2. Comprehensive hard materials

    CERN Document Server

    2014-01-01

    Comprehensive Hard Materials deals with the production, uses and properties of the carbides, nitrides and borides of these metals and those of titanium, as well as tools of ceramics, the superhard boron nitrides and diamond and related compounds. Articles include the technologies of powder production (including their precursor materials), milling, granulation, cold and hot compaction, sintering, hot isostatic pressing, hot-pressing, injection moulding, as well as on the coating technologies for refractory metals, hard metals and hard materials. The characterization, testing, quality assurance and applications are also covered. Comprehensive Hard Materials provides meaningful insights on materials at the leading edge of technology. It aids continued research and development of these materials and as such it is a critical information resource to academics and industry professionals facing the technological challenges of the future. Hard materials operate at the leading edge of technology, and continued res...

  3. Optical waveguides in hard crystalline materials

    NARCIS (Netherlands)

    Pollnau, Markus

    2005-01-01

    The recent results of our research group and collaborators in the field of fabrication, characterization, and applications of optical waveguides in hard crystalline materials, specifically in sapphire and Ti:sapphire, are reviewed.

  4. New materials for radiation hard semiconductor detectors

    CERN Document Server

    Sellin, P J; CERN. Geneva

    2006-01-01

    We present a review of the current status of research into new semiconductor materials for use as particle tracking detectors in very high radiation environments. This work is carried out within the framework of the CERN RD50 collaboration, which is investigating detector technologies suitable for operation at the proposed Super-LHC facility (SLHC). Tracking detectors operating at the SLHC in this environment will have to be capable of withstanding radiation levels arising from a luminosity of 1035 cm-2s-1 which will present severe challenges to current tracking detector technologies. The "new materials" activity within RD50 is investigating the performance of various semiconductor materials that potentially offer radiation hard alternatives to silicon devices. The main contenders in this study are silicon carbide, gallium nitride and amorphous silicon. In this paper we review the current status of these materials, in terms of material quality, commercial availability, charge transport properties, and radiati...

  5. Standard test methods for rockwell hardness of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 These test methods cover the determination of the Rockwell hardness and the Rockwell superficial hardness of metallic materials by the Rockwell indentation hardness principle. This standard provides the requirements for Rockwell hardness machines and the procedures for performing Rockwell hardness tests. 1.2 This standard includes additional requirements in annexes: Verification of Rockwell Hardness Testing Machines Annex A1 Rockwell Hardness Standardizing Machines Annex A2 Standardization of Rockwell Indenters Annex A3 Standardization of Rockwell Hardness Test Blocks Annex A4 Guidelines for Determining the Minimum Thickness of a Test Piece Annex A5 Hardness Value Corrections When Testing on Convex Cylindrical Surfaces Annex A6 1.3 This standard includes nonmandatory information in appendixes which relates to the Rockwell hardness test. List of ASTM Standards Giving Hardness Values Corresponding to Tensile Strength Appendix X1 Examples of Procedures for Determining Rockwell Hardness Uncertainty Appendix X...

  6. Standard test methods for rockwell hardness of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 These test methods cover the determination of the Rockwell hardness and the Rockwell superficial hardness of metallic materials by the Rockwell indentation hardness principle. This standard provides the requirements for Rockwell hardness machines and the procedures for performing Rockwell hardness tests. 1.2 This standard includes additional requirements in annexes: Verification of Rockwell Hardness Testing Machines Annex A1 Rockwell Hardness Standardizing Machines Annex A2 Standardization of Rockwell Indenters Annex A3 Standardization of Rockwell Hardness Test Blocks Annex A4 Guidelines for Determining the Minimum Thickness of a Test Piece Annex A5 Hardness Value Corrections When Testing on Convex Cylindrical Surfaces Annex A6 1.3 This standard includes nonmandatory information in appendixes which relates to the Rockwell hardness test. List of ASTM Standards Giving Hardness Values Corresponding to Tensile Strength Appendix X1 Examples of Procedures for Determining Rockwell Hardness Uncertainty Appendix X...

  7. Organic-Inorganic Hybrid Silica Material Derived from a Monosilylated Grubbs-Hoveyda Ruthenium Carbene as a Recyclable Metathesis Catalyst

    Directory of Open Access Journals (Sweden)

    Michel Wong Chi Man

    2010-08-01

    Full Text Available The synthesis of a monosilylated Grubbs-Hoveyda ruthenium alkylidene complex is described, as well as the preparation and characterization of the corresponding material by sol-gel cogelification with tetraethoxysilane (TEOS and the assay of this recyclable supported catalyst in ring-closing diene and enyne metathesis reactions under thermal and microwave conditions.

  8. Heterogeneous oxidation catalysis on ruthenium: bridging the pressure and materials gaps and beyond

    Science.gov (United States)

    Assmann, J.; Narkhede, V.; Breuer, N. A.; Muhler, M.; Seitsonen, A. P.; Knapp, M.; Crihan, D.; Farkas, A.; Mellau, G.; Over, H.

    2008-05-01

    It is shown that both the materials and the pressure gaps can be bridged for ruthenium in heterogeneous oxidation catalysis using the oxidation of carbon monoxide as a model reaction. Polycrystalline catalysts, such as supported Ru catalysts and micrometer-sized Ru powder, were compared to single-crystalline ultrathin RuO2 films serving as model catalysts. The microscopic reaction steps on RuO2 were identified by a combined experimental and theoretical approach applying density functional theory. Steady-state CO oxidation and transient kinetic experiments such as temperature-programmed desorption were performed with polycrystalline catalysts and single-crystal surfaces and analyzed on the basis of a microkinetic model. Infrared spectroscopy turned out to be a valuable tool allowing us to identify adsorption sites and adsorbed species under reaction conditions both for practical catalysts and for the model catalyst over a wide temperature and pressure range. The close interplay of the experimental and theoretical surface science approach with the kinetic and spectroscopic research on catalysts applied in plug-flow reactors provides a synergistic strategy for improving the performance of Ru-based catalysts. The most active and stable state was identified with an ultrathin RuO2 shell coating a metallic Ru core. The microscopic processes causing the structural deactivation of Ru-based catalysts while oxidizing CO have been identified.

  9. Characterization And Dissolution Properties Of Ruthenium Oxides

    Science.gov (United States)

    Ruthenium oxides (RuO2•1.10H2O and RuO2) have been synthesized by forced hydrolysis and oxidation of ruthenium chloride. The resulting materials were extensively characterized to determine the crystallinity, surface area, and ruthenium oxidation ...

  10. IR-doped ruthenium oxide catalyst for oxygen evolution

    Science.gov (United States)

    Valdez, Thomas I. (Inventor); Narayanan, Sekharipuram R. (Inventor)

    2012-01-01

    A method for preparing a metal-doped ruthenium oxide material by heating a mixture of a doping metal and a source of ruthenium under an inert atmosphere. In some embodiments, the doping metal is in the form of iridium black or lead powder, and the source of ruthenium is a powdered ruthenium oxide. An iridium-doped or lead-doped ruthenium oxide material can perform as an oxygen evolution catalyst and can be fabricated into electrodes for electrolysis cells.

  11. Evaluation of hardness and wear resistance of interim restorative materials.

    Science.gov (United States)

    Savabi, Omid; Nejatidanesh, Farahnaz; Fathi, Mohamad Hossein; Navabi, Amir Arsalan; Savabi, Ghazal

    2013-03-01

    The interim restorative materials should have certain mechanical properties to withstand in oral cavity. The aim of this study was to evaluate the hardness and wear resistance of interim restorative materials. Fifteen identical rectangular shape specimens with dimensions of 2 mm × 10 mm × 30 mm were made from 7 interim materials (TempSpan, Protemp 3 Garant, Revotek, Unifast LC, Tempron, Duralay, and Acropars). The Vickers hardness and abrasive wear of specimens were tested in dry conditions and after 1 week storage in artificial saliva. The depth of wear was measured using surface roughness inspection device. Data were subjected to Kruskal-Wallis and Mann-Whitney tests. The Pearson correlation coefficient was used to determine the relationship between hardness and wear (α =0.05). TempSpan had the highest hardness. The wear resistance of TempSpan (in dry condition) and Revotek (after conditioning in artificial saliva) was significantly higher (P materials (P = 0.281, r = -0.31). Hardness and wear resistance of interim resins are material related rather than category specified.

  12. Soft vesicles in the synthesis of hard materials.

    Science.gov (United States)

    Dong, Renhao; Liu, Weimin; Hao, Jingcheng

    2012-04-17

    Vesicles of surfactants in aqueous solution have received considerable attention because of their use as simple model systems for biological membranes and their applications in various fields including colloids, pharmaceuticals, and materials. Because of their architecture, vesicles could prove useful as "soft" templates for the synthesis of "hard materials". The vesicle phase, however, has been challenging and difficult to work with in the construction of hard materials. In the solution-phase synthesis of various inorganic or macromolecular materials, templating methods provide a powerful strategy to control the size, morphology, and composition of the resulting micro- and nanostructures. In comparison with hard templates, soft templates are generally constructed using amphiphilic molecules, especially surfactants and amphiphilic polymers. These types of compounds offer advantages including the wide variety of available templates, simple fabrication processes under mild conditions, and easy removal of the templates with less damage to the final structures. Researchers have used many ordered molecular aggregates such as vesicles, micelles, liquid crystals, emulsion droplets, and lipid nanotubes as templates or structure-directing agents to control the synthesis or assembly hard micro- and nanomaterials composed from inorganic compounds or polymers. In addition to their range of sizes and morphologies, vesicles present unique structures that can simultaneously supply different microenvironments for the growth and assembly of hard materials: the inner chamber of vesicles, the outer surface of the vesicles, and the space between bilayers. Two main approaches for applying vesicles in the field of hard materials have been explored: (i) in situ synthesis of micro- or nanomaterials within a specific microenvironment by vesicle templating and (ii) the assembly or incorporation of guest materials during the formation of vesicles. This Account provides an in-depth look at

  13. Impedance spectroscopic analysis of composite electrode from activated carbon/conductive materials/ruthenium oxide for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Taer, E.; Awitdrus,; Farma, R. [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Department of Physics, Faculty of Mathematics and Natural Sciences, University of Riau, 28293 Pekanbaru, Riau (Indonesia); Deraman, M., E-mail: madra@ukm.my; Talib, I. A.; Ishak, M. M.; Omar, R.; Dolah, B. N. M.; Basri, N. H.; Othman, M. A. R. [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Kanwal, S. [ICCBS, H.E.J. Research Institute of Chemistry, University of Karachi, 75270 Karachi (Pakistan)

    2015-04-16

    Activated carbon powders (ACP) were produced from the KOH treated pre-carbonized rubber wood sawdust. Different conductive materials (graphite, carbon black and carbon nanotubes (CNTs)) were added with a binder (polivinylidene fluoride (PVDF)) into ACP to improve the supercapacitive performance of the activated carbon (AC) electrodes. Symmetric supercapacitor cells, fabricated using these AC electrodes and 1 molar H{sub 2}SO{sub 4} electrolyte, were analyzed using a standard electrochemical impedance spectroscopy technique. The addition of graphite, carbon black and CNTs was found effective in reducing the cell resistance from 165 to 68, 23 and 49 Ohm respectively, and increasing the specific capacitance of the AC electrodes from 3 to 7, 17, 32 F g{sup −1} respectively. Since the addition of CNTs can produce the highest specific capacitance, CNTs were chosen as a conductive material to produce AC composite electrodes that were added with 2.5 %, 5 % and 10 % (by weight) electro-active material namely ruthenium oxide; PVDF binder and CNTs contents were kept at 5 % by weight in each AC composite produced. The highest specific capacitance of the cells obtained in this study was 86 F g{sup −1}, i.e. for the cell with the resistance of 15 Ohm and composite electrode consists of 5 % ruthenium oxide.

  14. Ruthenium oxides supported on heterostructured CoPO-MCF materials for catalytic oxidation of vinyl chloride emissions.

    Science.gov (United States)

    Wang, Chao; Tian, Chengcheng; Guo, Yanglong; Zhang, Zhendong; Hua, Wenchao; Zhan, Wangcheng; Guo, Yun; Wang, Li; Lu, Guanzhong

    2018-01-15

    A novel heterostructured material, cobalt phosphate-SiO2 mesostructured cellular foams (CoPO-MCF), was successfully synthesized by in situ growth. The material was characterized by X-ray diffraction (XRD), nitrogen sorption, temperature-programmed reduction (H2-TPR and CO-TPR), temperature-programmed desorption of NH3 (NH3-TPD), and X-ray photoelectron spectroscopy (XPS). A ruthenium precursor was readily introduced and highly dispersed on the CoPO nanophases of the CoPO-MCF through an impregnation method. The resulting Ru/CoPO-MCF catalyst exhibited high catalytic activity for the oxidation of vinyl chloride (VC). The results of three consecutive runs and long-term tests showed high stability of the Ru/CoPO-MCF for the catalytic oxidation of VC. The unique heterostructures of the CoPO-MCF not only improve the reducibility and acidity of the MCF but also strengthen the interaction between ruthenium oxide nanoparticles and the CoPO-MCF support, which contributes to the enhanced catalytic performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Is osmium diboride an ultra-hard material?

    Science.gov (United States)

    Yang, Jun; Sun, Hong; Chen, Changfeng

    2008-06-11

    We report first-principles calculations of ideal tensile and shear strength for the recently synthesized orthorhombic OsB2 that is a primary example of a new class of ultra-hard materials synthesized by combining small, light, and covalent elements with large, electron-rich transition metals. Our calculations show that the shear strength on the (001) plane is highly anisotropic with a low peak stress of 9.1 GPa in the (001)[010] shear direction but a much higher peak stress of 26.9 GPa in the (001)[100] direction. The strong resistance against (001)[100] shear deformation prevents the indenter from making a deep imprint, giving rise to a high Vickers hardness on the (001) plane, despite the weak shear strength in the (001)[010] shear direction. The calculated peak stress of 26.9 GPa in the (001)[100] shear direction agrees well with the 30 GPa Vickers hardness observed experimentally on the (001) plane in OsB2. However, the weak shear strength (9.1 GPa) in the (001)[010] shear direction severely limits its application as abrasives and cutting tools for ferrous metals as well as scratch-resistance coatings. Our results highlight the importance of understanding atomistic deformation modes under various loading conditions in designing new ultra-hard materials.

  16. Multifunctional carbon nanotubes/ruthenium purple thin films: preparation, characterization and study of application as sensors and electrochromic materials.

    Science.gov (United States)

    Husmann, Samantha; Zarbin, Aldo J G

    2015-04-07

    This work reports the preparation, characterization and application as both electrochromic materials and electrochemical sensors of novel materials: carbon nanotubes/ruthenium purple nanocomposites. Using an innovative route based on a heterogeneous electrochemical reaction involving iron oxide species encapsulated within the cavities of the carbon nanotubes, the nanocomposite materials were obtained as transparent thin films deposited over transparent electrodes. Several experimental parameters related to the nanocomposite synthesis were evaluated and related to the characteristics of the obtained materials, such as morphology and stability. The films were characterized by UV-Vis and Raman spectroscopy, scanning electron microscopy, X-ray diffraction, cyclic voltammetry and UV-Vis and Raman spectroelectrochemistry. Four different materials were applied as H2O2 sensors and exhibited impressive analytical parameters, including a limit of detection of 1.27 nmol L(-1) and a sensitivity of 39.6 A M(-1) cm(-2). These nanocomposites also showed great electrochromic properties, with high stability and coloration efficiency over 95% maintained during stability cycles.

  17. Is yne-diamond a super-hard material?

    Science.gov (United States)

    Bu, Hongxia; Zhao, Mingwen; Xi, Yan; Wang, Xiaopeng; Peng, Hua; Wang, Chunlei; Liu, Xiangdong

    2012-12-01

    Yne-diamond —a new carbon allotrope constructed by inserting two carbon atoms into the carbon-carbon bonds of diamond was expected to have super-hardness comparable to diamond because of the three-dimensional network of strong sp-sp3 and sp-sp bonds. However, from a theoretical point of view, this idea has never been validated carefully. Based on first-principles calculations, we present the first theoretical evidence that, in contrast to the early expectation, yne-diamond possesses low ideal tensile strength, low shear strength and small Pugh's modulus ratio, owning to the large void network in the covalent bond skeleton. Combined with a simple model, we predict that the yne-diamond family will not be a super-hard material family. This provides a new understanding of the mechanical properties of carbon allotropes containing sp-hybridized carbon atoms.

  18. Radiation Hard Sensor Materials for the CMS Tracker Upgrade

    CERN Document Server

    Bergholz, Matthias

    2011-01-01

    The upgrade of the LHC machine to deliver a significantly higher luminosity of about 5x10$^{34}$ cm$^{-2}$s$^{-1}$ is planned to be operational after 2020. This will significantly increase the radiation dose of the inner detector systems, requiring new radiation hard sensor materials for the CMS Tracker. To identify the appropriate materials, which are able to withstand the radiation environment in the middle to outer layers of the CMS Tracker during the full lifetime of the high luminosity LHC, a large irradiation and measurement campaign has been started. Several test structures and sensors have been designed and manufactured on 18 different combinations of wafer materials, thicknesses and production technologies. The structures will be electrically characterized before and after irradiation with different doses of neutrons and protons.

  19. Surface Hardness of Resin Cement Polymerized under Different Ceramic Materials

    Directory of Open Access Journals (Sweden)

    Pimmada Kesrak

    2012-01-01

    Full Text Available Objectives. To evaluate the surface hardness of two light-cured resin cements polymerized under different ceramic discs. Methods. 40 experimental groups of 2 light-cured resin cement specimens (Variolink Veneer and NX3 were prepared and polymerized under 5 different ceramic discs (IPS e.max Press HT, LT, MO, HO, and Cercon of 4 thicknesses (0.5, 1.0, 1.5, and 2.0 mm, Those directly activated of both resin cements were used as control. After light activation and 37∘C storage in an incubator, Knoop hardness measurements were obtained at the bottom. The data were analyzed with three-way ANOVA, t-test, and one-way ANOVA. Results. The KHN of NX3 was of significantly higher than that of Variolink Veneer (<0.05. The KHN of resin cement polymerized under different ceramic types and thicknesses was significant difference (<0.05. Conclusion. Resin cements polymerized under different ceramic materials and thicknesses showed statistically significant differences in KHN.

  20. Ductile Binder Phase For Use With Almgb14 And Other Hard Ceramic Materials

    Science.gov (United States)

    Cook, Bruce A.; Russell, Alan; Harringa, Joel

    2005-07-26

    This invention relates to a ductile binder phase for use with AlMgB14 and other hard materials. The ductile binder phase, a cobalt-manganese alloy, is used in appropriate quantities to tailor good hardness and reasonable fracture toughness for hard materials so they can be used suitably in industrial machining and grinding applications.

  1. Radiochemistry of ruthenium

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, W W; Metcalf, S G; Barney, G S

    1984-06-01

    Information on ruthenium is presented. Topics include the following; isotopes and nuclear properties of ruthenium; review of the chemistry of ruthenium including metal and alloys, compounds of ruthenium, and solution chemistry; separation methods including volatilization of RuO{sub 4}, precipitation and coprecipitation, solvent extraction, chromatographic techniques, and analysis for radioruthenium. 445 refs., 7 figs., 23 tabs.

  2. Compression deformation of WC: atomistic description of hard ceramic material

    Science.gov (United States)

    Feng, Qing; Song, Xiaoyan; Liu, Xuemei; Liang, Shuhua; Wang, Haibin; Nie, Zuoren

    2017-11-01

    The deformation characteristics of WC, as a typical hard ceramic material, were studied on the nanoscale using atomistic simulations for both the single-crystal and polycrystalline forms under uniaxial compression. In particular, the effects of crystallographic orientation, grain boundary coordination and grain size on the origin of deformation were investigated. The deformation behavior of the single-crystal and polycrystalline WC both depend strongly on the orientation towards the loading direction. The grain boundaries play a significant role in the deformation coordination and the potential high fracture toughness of the nanocrystalline WC. In contrast to conventional knowledge of ceramics, maximum strength was obtained at a critical grain size corresponding to the turning point from a Hall–Petch to an inverse Hall–Petch relationship. For this the mechanism of the combined effect of dislocation motion within grains and the coordination of stress concentration at the grain boundaries were proposed. The present work has moved forward our understanding of plastic deformability and the possibility of achieving a high strength of nanocrystalline ceramic materials.

  3. Comparison of digestion methods for the determination of ruthenium in catalyst materials.

    Science.gov (United States)

    Suoranta, Terhi; Niemelä, Matti; Perämäki, Paavo

    2014-02-01

    A fusion method, an acid digestion method with a high pressure asher (HPA) and two microwave (MW)-assisted acid digestion methods were compared to investigate their suitability for the determination of Ru in catalyst materials. Ru contents in the digested samples were determined with inductively coupled plasma optical emission spectrometry (ICP-OES). Ru powder and three Ru compounds (RuO2 · xH2O, anhydrous RuO2 and RuCl3), possibly present in Ru catalysts, were digested and analyzed to compare the digestion efficiencies of the methods. Significant differences among the digestion efficiencies of the methods were observed; the fusion method having the best digestion efficiency for the compounds studied. The methods were applied for the determination of Ru in alumina- and carbon-supported catalysts. No differences among the methods were observed for these samples. © 2013 Published by Elsevier B.V.

  4. Liquid money or hard cash? Drowning into granular material

    CERN Document Server

    Bagnoli, Franco

    2016-01-01

    In British English, the term "hard cash" refers to the form of payment using coins or bill, rather than cheques or credit or money transfer. In American English, it is often prefixed by the adjective "cold". On the contrary, in Italian the equivalent expression "denaro liquido" can be literary translated as "liquid money". In French the expression is equivalent with the additional factor, with respect to the rest of this discussion, that money becomes "argent". We have therefore two very different points of view: Is money hard and cold, or rather liquid and "jingling" ("moneta sonante")? As usual, we shall investigate this topic starting from some comics about the duck family.

  5. Surface hardness of different restorative materials after long-term immersion in sports and energy drinks.

    Science.gov (United States)

    Erdemir, Ugur; Yildiz, Esra; Eren, Meltem Mert; Ozel, Sevda

    2012-01-01

    The purpose of this study was to evaluate the effect of sports and energy drinks on the surface hardness of different restorative materials over a 6-month period. Forty-two disk-shaped specimens were prepared for each of the four restorative materials tested: Compoglass F, Filtek Z250, Filtek Supreme, and Premise. Specimens were immersed for 2 min daily, up to 6 months, in six storage solutions (n=7 per material for each solution): distilled water, Powerade, Gatorade, X-IR, Burn, and Red Bull. Surface hardness was measured at baseline, after 1 week, 1 month, and 6 months. Data were analyzed statistically using repeated measures ANOVA followed by the Bonferroni test for multiple comparisons (α=0.05). Surface hardness of the restorative materials was significantly affected by both immersion solution and immersion period (p<0.001). All tested solutions induced significant reduction in surface hardness of the restorative materials over a 6-month immersion period.

  6. Correlation of impression removal force with elastomeric impression material rigidity and hardness.

    Science.gov (United States)

    Walker, Mary P; Alderman, Nick; Petrie, Cynthia S; Melander, Jennifer; McGuire, Jacob

    2013-07-01

    Difficult impression removal has been linked to high rigidity and hardness of elastomeric impression materials. In response to this concern, manufacturers have reformulated their materials to reduce rigidity and hardness to decrease removal difficulty; however, the relationship between impression removal and rigidity or hardness has not been evaluated. The purpose of this study was to determine if there is a positive correlation between impression removal difficulty and rigidity or hardness of current elastomeric impression materials. Light- and medium-body polyether (PE), vinylpolysiloxane (VPS), and hybrid vinyl polyether siloxane (VPES) impression materials were tested (n = 5 for each material/consistency/test method). Rigidity (elastic modulus) was measured via tensile testing of dumbbell-shaped specimens (Die C, ASTM D412). Shore A hardness was measured using disc specimens according to ASTM D2240-05 test specifications. Impressions were also made of a custom stainless steel model using a custom metal tray that could be attached to a universal tester to measure associated removal force. Within each impression material consistency, one-factor ANOVA and Tukey's post hoc analyses (α = 0.05) were used to compare rigidity, hardness, and removal force of the three types of impression materials. A Pearson's correlation (α = 0.05) was used to evaluate the association between impression removal force and rigidity or hardness. With medium-body materials, VPS exhibited significantly higher (p ≤ 0.05) rigidity and hardness than VPES or PE, while PE impressions required significantly higher (p ≤ 0.05) removal force than VPS or VPES impressions. With light-body materials, VPS again demonstrated significantly higher (p ≤ 0.05) hardness than VPES or PE, while the rigidity of the light-body materials did not significantly differ between materials (p > 0.05); however, just as with the medium-body materials, light-body PE impressions required significantly higher (p

  7. On the relationship between indentation hardness and modulus, and the damage resistance of biological materials.

    Science.gov (United States)

    Labonte, David; Lenz, Anne-Kristin; Oyen, Michelle L

    2017-07-15

    The remarkable mechanical performance of biological materials is based on intricate structure-function relationships. Nanoindentation has become the primary tool for characterising biological materials, as it allows to relate structural changes to variations in mechanical properties on small scales. However, the respective theoretical background and associated interpretation of the parameters measured via indentation derives largely from research on 'traditional' engineering materials such as metals or ceramics. Here, we discuss the functional relevance of indentation hardness in biological materials by presenting a meta-analysis of its relationship with indentation modulus. Across seven orders of magnitude, indentation hardness was directly proportional to indentation modulus. Using a lumped parameter model to deconvolute indentation hardness into components arising from reversible and irreversible deformation, we establish criteria which allow to interpret differences in indentation hardness across or within biological materials. The ratio between hardness and modulus arises as a key parameter, which is related to the ratio between irreversible and reversible deformation during indentation, the material's yield strength, and the resistance to irreversible deformation, a material property which represents the energy required to create a unit volume of purely irreversible deformation. Indentation hardness generally increases upon material dehydration, however to a larger extent than expected from accompanying changes in indentation modulus, indicating that water acts as a 'plasticiser'. A detailed discussion of the role of indentation hardness, modulus and toughness in damage control during sharp or blunt indentation yields comprehensive guidelines for a performance-based ranking of biological materials, and suggests that quasi-plastic deformation is a frequent yet poorly understood damage mode, highlighting an important area of future research. Instrumented

  8. Comparison of hardness of three temporary filling materials cured by two light-curing devices.

    Science.gov (United States)

    Bodrumlu, E; Koçak, M M; Hazar Bodrumlu, E; Ozcan, S; Koçak, S

    2014-01-01

    Polymerization ability of light-curing devices can affect the light-cured material hardness. The purpose of the present study was to evaluate and compare the hardness of three temporary filling materials that had been light-cured by either a light emitting diode (LED) or a halogen light-curing unit. The temporary filling materials, First Fill, Voco Clip and Bioplic, were placed in wells in a Teflon plate. The 24 specimens of each material were divided into two groups (N.=12/group) for photo-activation by either of the two light-curing units. The LED or halogen device was applied for 40s to the top surface of each specimen. A Knoop hardness test was performed on the top and bottom surface of each specimen, with five measurements per specimen. The highest hardness values for both the LED and halogen treated groups were observed for First Fill and the lowest values were for Voco Clip in top and bottom surfaces. The hardness obtained for the three materials with the halogen unit were significantly higher than the values obtained with the LED unit in both surfaces (Phardness values on the top and bottom surfaces than Voco Clip and Bioplic temporary materials. The hardness of light-cured temporary filling materials can be affected by the type of light-curing unit.

  9. Evaluation of colour and hardness changes of soft lining materials in food colorant solutions.

    Science.gov (United States)

    Canay, S; Hersek, N; Tulunoğlu, I; Uzun, G

    1999-10-01

    The aim of this study was to measure the colour stability and viscoelastic properties of three commercially available soft lining materials in vitro, by exposing them to 3% erythrosine, tartrazine and sunset yellow solutions. The colour changes were determined using a computer controlled spectrophotometer. The colour change of three soft lining materials--Molloplast B, Flexor and Coe Super Soft--were determined after 1, 3 and 6 months storage in three different food colorant solutions. The colour changes of Molloplast B was not noticeable. Only the initial colour value of Flexor was significantly different from the other time interval colour measurements. On the other hand, the colour difference of Coe Super Soft was found to be significantly different at all comparative time interval measurements (P<0.05). According to Shore A hardness values, Molloplast B had an initial hardness of 44 in all three solutions, and there was a slight increase after 6 months. Flexor had an initial hardness of 39, at the end of 6 months the hardness changed a little. Coe Super Soft was fairly hard after processing and Shore A hardness was initially 89 which increased to 95 later on. According to these results, only the hardness values of Coe Super Soft showed a statistically significant difference when compared using Wilcoxon signed rank test at the P<0.05 level. As a conclusion, silicon type soft lining material seems to be more resistant to colour change and hardness than the acrylic type soft liners.

  10. Tactile Perception of Roughness and Hardness to Discriminate Materials by Friction-Induced Vibration

    National Research Council Canada - National Science Library

    Shuyang Ding; Yunlu Pan; Mingsi Tong; Xuezeng Zhao

    2017-01-01

    ... skin. The tactile perception of surface roughness and material hardness can be estimated by skin vibrations generated during a fingertip stroking of a surface instead of being maintained in a static position...

  11. On the Invariance of Hardness at Vickers Indentation of Pre-Stressed Materials

    Directory of Open Access Journals (Sweden)

    Per-Lennart Larsson

    2017-07-01

    Full Text Available The influence from residual surface stresses on global indentation properties, i.e., hardness and size of the contact area, have been studied quite frequently in recent years. A fundamental assumption when evaluating such tests is that the material hardness is independent of any residual stresses. This assumption has been verified in the case of cone indentation of classical Mises elastoplastic materials. However, a detailed investigation of this feature in the case of three-dimensional indentation, i.e., Vickers and Berkovic indentation, has not been presented previously. It is therefore the aim of the present study to remedy this shortcoming using finite element methods. The numerical results pertinent to Vickers indentation clearly show that the material hardness is independent of residual (or applied stresses (also in case of three-dimensional indentation problems. The limitations of the validity of hardness invariance are also discussed in some detail.

  12. Preparation of hard magnetic materials in thin film form

    Energy Technology Data Exchange (ETDEWEB)

    Pigazo, F.; Palomares, F.J. [Instituto de Ciencia de Materiales de Madrid-CSIC, c/ Sor Juana Ines de la Cruz 3, 28049 Madrid (Spain); Cebollada, F. [EUITT-UPM, Carretera de Valencia km 7, 28031 Madrid (Spain); Gonzalez, J.M. [Unidad Asociada ICMM-IMA, c/ Sor Juana Ines de la Cruz 3, 28049 Madrid (Spain)], E-mail: jesus.m.gonzalez@icmm.csic.es

    2008-07-15

    We report on the preparation, by means of pulsed laser ablation deposition, of trilayers of nominal composition Cr/SmCo{sub 5}/Cr//Si with thicknesses in the order of 250/240/125 nm, respectively. According to the results of the structural, chemical and magnetic characterizations performed in our as-deposited samples, the Sm-Co layer was structurally amorphous, exhibited abrupt compositional interfaces with the capping and buffering layers, and coercivities of a few hundreds of Oe. Magnetic hardness was developed upon submitting the samples to current anneals under vacuum at temperatures in the range of 540-670 deg. C. The hardening process was followed in detail by correlating the phase distribution, the nature of the interlayer atomic diffusion processes, the occurrence of textures and the temperature dependence of the coercive force. From our results we conclude about (i) the occurrence of a large degree of Co diffusion/segregation, which results in the detection, from the diffraction and magnetometric results, of the presence of CoCr alloys in the treated samples, and (ii) the close correlation, evidenced from the fits of the temperature dependence of the coercive force to the micromagnetic model, between the coercivity optimization and the crystallinity enhancement of the SmCo{sub 5} grains.

  13. Shore hardness and tensile bond strength of long-term soft denture lining materials.

    Science.gov (United States)

    Kim, Bong-Jun; Yang, Hong-So; Chun, Min-Geoung; Park, Yeong-Joon

    2014-11-01

    Reduced softness and separation from the denture base are the most significant problems of long-term soft lining materials. The purpose of this study was to evaluate the durometer Shore A hardness and tensile bond strength of long-term soft denture lining materials and to investigate the correlation between these 2 properties. A group of 7 soft lining materials, 6 silicone based (Dentusil, GC Reline Soft, GC Reline Ultrasoft, Mucopren Soft, Mucosoft, Sofreliner Tough) and 1 acrylic resin based (Durabase), were evaluated for durometer Shore A hardness and tensile bond strength to heat-polymerized denture base resin (Lucitone 199). A specially designed split mold and loading assembly with a swivel connector were used for the durometer Shore A hardness test and tensile bond strength test to improve accuracy and facilitate measurement. Three specimens of each product were stored in a 37°C water bath, and durometer Shore A hardness tests were carried out after 24 hours and 28 days. A tensile bond strength test was carried out for 10 specimens of each product, which were stored in a 37°C water bath for 24 hours before the test. Repeated-measures ANOVA, the Kruskal-Wallis and Duncan multiple range tests, and the Spearman correlation were used for statistical analyses. The repeated-measures ANOVA found significant durometer Shore A hardness differences for the materials (Phardness (21.30 ±0.29 for 24 hours, 34.73 ±0.47 for 28 days), and GC Reline Soft showed the highest mean durometer Shore A hardness (50.13 ±0.48 for 24 hours, 57.20 ±0.28 for 28 days). The Kruskal-Wallis test found a significant difference in the mean tensile bond strength values (Phardness showed a statistically insignificant moderate positive correlation (r=0.571, P=.180 for Shore A hardness 24 hours versus tensile bond strength; r=0.607, P=.148 for Shore A hardness 28 days versus tensile bond strength). Within the limitations of this study, significant differences were found in durometer Shore A

  14. The material co-construction of hard science fiction and physics

    Science.gov (United States)

    Hasse, Cathrine

    2015-12-01

    This article explores the relationship between hard science fiction and physics and a gendered culture of science. Empirical studies indicate that science fiction references might spur some students' interest in physics and help develop this interest throughout school, into a university education and even further later inspire the practice of doing science. There are many kinds of fiction within the science fiction genre. In the presented empirical exploration physics students seem particularly fond of what is called `hard science fiction': a particular type of science fiction dealing with technological developments (Hartwell and Cramer in The hard SF renaissance, Orb/TOR, New York, 2002). Especially hard science fiction as a motivating fantasy may, however, also come with a gender bias. The locally materialized techno-fantasies spurring dreams of the terraforming of planets like Mars and travels in time and space may not be shared by all physics students. Especially female students express a need for other concerns in science. The entanglement of physics with hard science fiction may thus help develop some students' interest in learning school physics and help create an interest for studying physics at university level. But research indicates that especially female students are not captured by the hard techno-fantasies to the same extent as some of their male colleagues. Other visions (e.g. inspired by soft science fiction) are not materialized as a resource in the local educational culture. It calls for an argument of how teaching science is also teaching cultural values, ethics and concerns, which may be gendered. Teaching materials, like the use of hard science fiction in education, may not just be (yet another) gender bias in science education but also carrier of particular visions for scientific endeavours.

  15. Influence of light-curing units and restorative materials on the micro hardness of resin cements

    Directory of Open Access Journals (Sweden)

    Kuguimiya Rosiane

    2010-01-01

    Full Text Available Aim: The aim of this study was to evaluate the effect of indirect restorative materials (IRMs and light-curing units (LCUs on the micro hardness of dual-cured resin cement. Materials and Methods: A total of 36 cylindrical samples (2 mm thick were prepared with dual-cured resin cement (Relyx ARC photo-activated with either a QTH (Optilight Plus for 40s or a LED (Radii light-curing unit for 65s. Photo-activation was performed through the 2-mm- thick IRMs and the samples were divided into six groups (n=6 according to the combination of veneering materials (without, ceramic and indirect resin and LCUs (QTH and LED. In the control group, the samples were light-cured with a QTH unit without the interposition of any restorative material. Vickers micro hardness test was performed on the top and bottom surfaces of each sample (load of 50 g for 15 secs. The data were statistically analyzed using a three-way ANOVA followed by Tukey x s post-hoc test ( P < 0.05. Results: There were no statistically significant differences on the top surface between the light curing-units ( P > 0.05; however, the LED provided greater hardness on the bottom surface when a ceramic material was used ( P < 0.05. The mean hardness in photo-activated samples, in which there was no interposition of indirect materials, was significantly greater ( P < 0.01. Conclusions: It may be concluded that the interposition of the restorative material decreased the micro hardness in the deeper cement layer. Such decrease, however, was lower when the ceramic was interposed and the cement light-cured with LED.

  16. Evaluation of hardness and color stability in the soft lining materials after thermocycling and chemical polishing.

    Science.gov (United States)

    Goiato, Marcelo Coelho; Falcón-Antenucci, Rosse Mary; Santos, Daniela Micheline dos; Pellizzer, Eduardo Piza

    2009-01-01

    The aim of this study was to evaluate the Shore A hardness and color stability of two soft lining materials after thermocycling and when chemical polishing was used or omitted. Two acrylic-based soft lining materials were tested: Coe-Soft and Soft Confort, 14 specimens were made for each material. They were distributed in four groups according to the treatment performed. The specimens were thermocycled (1000 cycles) and half of the group submitted to chemical polishing (methyl methacrylate). Shore A hardness was determined and color stability was calculated by means of Commission International de l'Eclairage Lab uniform color scale using a spectrophotometer, the measurements were made immediately after deflasked, chemical polishing and thermocycling. Analysis of variance (ANOVA) and Tukey's tests were performed at p Confort (10.60) showed significantly higher values than Coe-Soft (4.57). Coe-Soft (26.42) showed higher Shore A hardness values than Soft Confort (19.42). Chemical polishing did not influence in the color stability of both materials; however, influenced in the hardness values of Coe-Soft.

  17. Development and Study of Hard-Facing Materials on the Base of Heat-Resisting High-Hardness Steels for Plasma-Jet Hard- Facing in Shielding-Doping Nitrogen Atmosphere

    Science.gov (United States)

    Malushin, N. N.; Kovalev, A. P.; Valuev, D. V.; Shats, E. A.; Borovikov, I. F.

    2016-08-01

    The authors develop hard-facing materials on the base of heat-resisting highhardness steels for plasma-jet hard-facing in nitrogen atmosphere for manufacturing parts of mining and metallurgic equipment which significantly simplify the production process and effect a saving when producing bimetallic parts and tools.

  18. SOLVENT EXTRACTION OF RUTHENIUM

    Science.gov (United States)

    Hyman, H.H.; Leader, G.R.

    1959-07-14

    The separation of rathenium from aqueous solutions by solvent extraction is described. According to the invention, a nitrite selected from the group consisting of alkali nitrite and alkaline earth nitrite in an equimolecular quantity with regard to the quantity of rathenium present is added to an aqueous solution containing ruthenium tetrantrate to form a ruthenium complex. Adding an organic solvent such as ethyl ether to the resulting mixture selectively extracts the rathenium complex.

  19. Tactile Perception of Roughness and Hardness to Discriminate Materials by Friction-Induced Vibration.

    Science.gov (United States)

    Ding, Shuyang; Pan, Yunlu; Tong, Mingsi; Zhao, Xuezeng

    2017-11-28

    The human fingertip is an exquisitely powerful bio-tactile sensor in perceiving different materials based on various highly-sensitive mechanoreceptors distributed all over the skin. The tactile perception of surface roughness and material hardness can be estimated by skin vibrations generated during a fingertip stroking of a surface instead of being maintained in a static position. Moreover, reciprocating sliding with increasing velocities and pressures are two common behaviors in humans to discriminate different materials, but the question remains as to what the correlation of the sliding velocity and normal load on the tactile perceptions of surface roughness and hardness is for material discrimination. In order to investigate this correlation, a finger-inspired crossed-I beam structure tactile tester has been designed to mimic the anthropic tactile discrimination behaviors. A novel method of characterizing the fast Fourier transform integral (FFT) slope of the vibration acceleration signal generated from fingertip rubbing on surfaces at increasing sliding velocity and normal load, respectively, are defined as k v and k w , and is proposed to discriminate the surface roughness and hardness of different materials. Over eight types of materials were tested, and they proved the capability and advantages of this high tactile-discriminating method. Our study may find applications in investigating humanoid robot perceptual abilities.

  20. Tactile Perception of Roughness and Hardness to Discriminate Materials by Friction-Induced Vibration

    Directory of Open Access Journals (Sweden)

    Shuyang Ding

    2017-11-01

    Full Text Available The human fingertip is an exquisitely powerful bio-tactile sensor in perceiving different materials based on various highly-sensitive mechanoreceptors distributed all over the skin. The tactile perception of surface roughness and material hardness can be estimated by skin vibrations generated during a fingertip stroking of a surface instead of being maintained in a static position. Moreover, reciprocating sliding with increasing velocities and pressures are two common behaviors in humans to discriminate different materials, but the question remains as to what the correlation of the sliding velocity and normal load on the tactile perceptions of surface roughness and hardness is for material discrimination. In order to investigate this correlation, a finger-inspired crossed-I beam structure tactile tester has been designed to mimic the anthropic tactile discrimination behaviors. A novel method of characterizing the fast Fourier transform integral (FFT slope of the vibration acceleration signal generated from fingertip rubbing on surfaces at increasing sliding velocity and normal load, respectively, are defined as kv and kw, and is proposed to discriminate the surface roughness and hardness of different materials. Over eight types of materials were tested, and they proved the capability and advantages of this high tactile-discriminating method. Our study may find applications in investigating humanoid robot perceptual abilities.

  1. Defect analysis of silicon detectors made of different materials for radiation hardness

    CERN Document Server

    Dezillie, B; Li, Z

    1999-01-01

    A comparative study of the radiation hardness of single pad detectors, manufactured from standard float-zone (FZ) and epitaxial (Epi) n-type monocrystal silicon with comparable initial resistivity is presented. Detectors 2processed from FZ and Epi material with a low (400 OMEGA cm and 500 OMEGA cm) and a high (approx 2 k OMEGA cm) initial resistivity have been irradiated up to 4x10 sup 1 sup 4 n/cm sup 2 and measured under the same conditions in order to study the influence of the initial resistivity on the detector radiation hardness.

  2. Reverse Design and Rapid Prototyping ABS Part Assembly with Hard Material

    Directory of Open Access Journals (Sweden)

    Xu Yaodong

    2016-01-01

    Full Text Available In order to realize the variant design of the existing product , and rapid completion of the manufacturing and assembly, a new product was designed by reverse design method,and manufactured by rapid prototyping technology to finish assembly with hard material part. An experiment of rapid prototyping part with different model scales assembling with metal part was done to find the right scale of 1.008 of the model in H/h tolerance fit and 0.1mm more in size in interference fit. Through the static theory analysis, the amount of the interference fit was calculated by equal torque in contrast with mechanical assembly.The result was further proved by ProE mechanica simulation for stress and strain. Applying the rule of the results in experiment,prototyping part assembly with hard material part in different types of fit can be realized.

  3. Impact and hardness optimisation of composite materials inspired by the babassu nut (Orbignya speciosa).

    Science.gov (United States)

    Staufenberg, Gerrit; Graupner, Nina; Müssig, Jörg

    2015-08-20

    The babassu nut is the fruit of the babassu palm Orbignya speciosa. The combination of hardness and impact strength is difficult to acquire for artificial materials, making the babassu nut a promising source for biomimetic inspiration. Unnotched Charpy impact tests, Shore D hardness tests and scanning electron microscopy were used for mechanical and microscopical analysis of the pericarp. Four major principles were found for a biomimetic approach: a hard core ((1); endocarp) is embedded in a soft outer layer of high impact strength ((2); epicarp) and is reinforced with fibres of variable fineness (3), some of which are oriented radial to the core (4). Biomimetic fibre-reinforced composites were produced using abstracted mechanisms of the babassu nut based on regenerated cellulose fibres (lyocell, L) with two different fineness values as reinforcement embedded in a polylactide (PLA) core matrix and polypropylene (PP) based outer layers. The biomimetic fibre composite reaches a significantly higher impact strength that is 1.6 times higher than the reference sample produced from a PLA/PP/L-blend. At the same time the hardness is slightly increased compared to PP/L.

  4. Effect of raw materials and hardening process on hardness of manually forged knife

    Science.gov (United States)

    Balkhaya, Suwarno

    2017-06-01

    Knives are normally made by forging process either using a machine or traditional method by means of hammering process. This present work was conducted to study the effects of steel raw materials and hardening process on the hardness of manually forged knives. The knife samples were made by traditional hammering (forging) process done by local blacksmith. Afterward, the samples were heat treated with two different hardening procedures, the first was based on the blacksmith procedure and the second was systematically done at the laboratory. The forging was done in the temperature ranged between 900-950°C, while the final temperature ranged between 650-675°C. The results showed that knives made of spring steel and heat treated in simulated condition at the laboratory obtained higher level of hardness, i.e. 62 HRC. In general, knives heat treated by local blacksmith had lower level of hardness that those obtained from simulated condition. Therefore, we concluded that the traditional knife quality in term of hardness can be improved by optimizing the heat treatment schedule.

  5. Evaluation by extended Hückel method on the hardness of the B–C–N materials

    Directory of Open Access Journals (Sweden)

    Hideaki Takashima and Yoshinori Kanno

    2005-01-01

    Full Text Available Hard materials, e.g. diamond and cubic boron nitride (c-BN, are widely applied to improve the lifetime and the performance of many kinds of cutting and forming tools. These materials are usually used at high temperature, so the study of stability on these materials at high temperature is very important. However, diamond is a low resistance to the oxidation, it should be replaced with the boron-based hard materials. Recently, boron–carbon–nitrogen (B–C–N ternary materials are expected to possess a high hardness, a high thermal stability at high temperature. We estimated the hardness and the stability of B–C–N materials at high temperature by the extended Hückel method. The extended Hückel method is one of the molecular orbital calculations and needs the cluster model of materials for the calculation. The cluster model of B–C–N materials was regarded as a zinc blende structure. In the present work, we used two physical quantities, i.e. a cohesive energy and an energy fluctuation, as a measure of hardness and stability of materials. The cohesive energy indicates the coherence of bonds between atoms. The energy fluctuation shows the reactivity of materials. Hardness, structure, solid-state properties and reactivity of materials can be estimated from these physical quantities. When the composition of B–C–N materials was boron: 25 at.%, nitrogen: 25 at.% and carbon: 50 at.%, the cohesive energy was the lowest. This result implies B–C–N ternary materials are not harder than c-BN and/or diamond. Cubic-BN was the lowest energy fluctuation of B–C–N materials, and the energy fluctuation increased as increasing of carbon atom. The reactivity of B–C–N materials was high at a high temperature with an increase of carbon atoms. These results imply that B–C–N materials are not suitable for the hard cutting materials.

  6. Material engineering for the development of ultra-radiation hard semiconductor detectors

    CERN Document Server

    Bruzzi, M

    2004-01-01

    A possible upgrade of the CERN Large Hadron Collider luminosity up to 10**3**5cm**-**2s**-**1 will rise the hadron fluences in the inner detector region of the future high energy physics experiments up to similar to 10**1**6cm**-**2, well beyond the present operational limits of state-of-art Si tracking detectors. The goal of the CERN RD50 collaboration is to push the semiconductor detector technology beyond these limits, through the development of radiation hard bulk materials and the optimisation of the electrode configuration of the device. Recent results of the RD50 collaboration concerning material engineering are presented.

  7. Application of Hard Metal Weld Deposit in the Area of Mixing Organic Materials

    Directory of Open Access Journals (Sweden)

    Jiří Votava

    2014-01-01

    Full Text Available Any machine part is subject to degradation processes. Intensive wear occurs either when two bearing surfaces come into contact or when loose particles rub the function surface of a machine part. Soil processing machines are a good example. A similar process of abrasive wear occurs also in mixing machines or lines for material transport, such as worm-conveyors. The experiment part of this paper analyses hard metal weld deposit dedicated for renovation of abrasive stressed surfaces. In order to prolong the service life of a blade disc in a mixing machine Kreis-Biogas-Dissolver, the technology of hard surfacing by an electric arc was used. Tested hard metal electrodes were applied on a steel tape class 11 373. To eliminate mixing with the base material, weld beads were applied in two layers. Firstly, the weld bead was visually analyzed on a binocular microscope. Further, weld bead as well as the base material was analyzed from the metallographic point of view, whose aim was to identify the structure of weld metal and the origin of microcracks in weld bead. Moreover, there was also measured microhardness of weld metal. Abrasive resistance was tested according to the norm ČSN 01 5084, which is an abrasive cloth test. As in the mixing process also erosion wear occurs, there was also processed a test on a Bond device simulating stress of test samples by loose abrasive particles. The abrading agents were formed by broken stones of 8–16 mm in size. Based on the results of the individual tests, the recommendation of usage hard metal electrodes for prolonging service life of machine parts will be made.

  8. Manganese mono-boride, an inexpensive room temperature ferromagnetic hard material

    Science.gov (United States)

    Ma, Shuailing; Bao, Kuo; Tao, Qiang; Zhu, Pinwen; Ma, Teng; Liu, Bo; Liu, Yazhou; Cui, Tian

    2017-03-01

    We synthesized orthorhombic FeB-type MnB (space group: Pnma) with high pressure and high temperature method. MnB is a promising soft magnetic material, which is ferromagnetic with Curie temperature as high as 546.3 K, and high magnetization value up to 155.5 emu/g, and comparatively low coercive field. The strong room temperature ferromagnetic properties stem from the positive exchange-correlation between manganese atoms and the large number of unpaired Mn 3d electrons. The asymptotic Vickers hardness (AVH) is 15.7 GPa which is far higher than that of traditional ferromagnetic materials. The high hardness is ascribed to the zigzag boron chains running through manganese lattice, as unraveled by X-ray photoelectron spectroscopy result and first principle calculations. This exploration opens a new class of materials with the integration of superior mechanical properties, lower cost, electrical conductivity, and fantastic soft magnetic properties which will be significant for scientific research and industrial application as advanced structural and functional materials.

  9. Hardness and modulus of elasticity of primary and permanent teeth after wear against different dental materials.

    Science.gov (United States)

    Galo, Rodrigo; Contente, Marta Maria Martins Giamatei; Galafassi, Daniel; Borsatto, Maria Cristina

    2015-01-01

    The purpose of this study was to determine the Young's modulus and the hardness of deciduous and permanent teeth following wear challenges using different dental materials. Wear challenges were performed against four dental materials: A resin-based fissure sealant (Fluoroshield(®)), a glass ionomer based fissure sealant (Vitremer(®)), and two microhybrid composite resins (Filtek Z250 and P90(®)). Using the pin-on-plate design, a deciduous or a permanent tooth was made into a pin (4 mm × 4 mm × 2 mm) working at a 3 N vertical load, 1 Hz frequency, and 900 cycles (15 min) with Fusayama artificial saliva as a lubricant. Before and after the tribological tests, the hardness and elasticity modulus of the tooth samples were measured by creating a nanoindentation at load forces up to 50 mN and 150 mN. All of the results were statistically analyzed using ANOVA and post-hoc Duncan's tests (P modulus of elasticity (P < 0.05) before or after the wear challenges for all of the dental materials tested. Wear challenges against the studied dental materials did not alter the properties of permanent or deciduous teeth after the application of a 3 N load.

  10. Manganese mono-boride, an inexpensive room temperature ferromagnetic hard material.

    Science.gov (United States)

    Ma, Shuailing; Bao, Kuo; Tao, Qiang; Zhu, Pinwen; Ma, Teng; Liu, Bo; Liu, Yazhou; Cui, Tian

    2017-03-06

    We synthesized orthorhombic FeB-type MnB (space group: Pnma) with high pressure and high temperature method. MnB is a promising soft magnetic material, which is ferromagnetic with Curie temperature as high as 546.3 K, and high magnetization value up to 155.5 emu/g, and comparatively low coercive field. The strong room temperature ferromagnetic properties stem from the positive exchange-correlation between manganese atoms and the large number of unpaired Mn 3d electrons. The asymptotic Vickers hardness (AVH) is 15.7 GPa which is far higher than that of traditional ferromagnetic materials. The high hardness is ascribed to the zigzag boron chains running through manganese lattice, as unraveled by X-ray photoelectron spectroscopy result and first principle calculations. This exploration opens a new class of materials with the integration of superior mechanical properties, lower cost, electrical conductivity, and fantastic soft magnetic properties which will be significant for scientific research and industrial application as advanced structural and functional materials.

  11. Effect of Whitening Dentifrice on Micro Hardness, Colour Stability and Surface Roughness of Aesthetic Restorative Materials.

    Science.gov (United States)

    Roopa, K B; Basappa, N; Prabhakar, A R; Raju, O S; Lamba, Gagandeep

    2016-03-01

    Whitening agents present in the novel whitening dentifrices may have deleterious effects over the aesthetic restorations. The present study evaluated the invitro effect of whitening dentifrice on micro hardness, colour stability and surface roughness on aesthetic restorative materials. Forty specimens each of compomer and of composite were prepared using brass mould. Specimens were equally divided into 4 groups. Group I (20 disks of compomer are subjected to brushing with conventional tooth paste) Group II (20 disks of composite subjected to brushing with conventional tooth paste), Group III (20 disks of compomer subjected to brushing with whitening tooth paste). Group IV (20 disks of composite subjected to brushing with whitening toothpaste). Each group was further divided into two subgroups, where 10 sample were subjected for two weeks of brushing with respective tooth paste and other 10 were subjected for four weeks of brushing. For the evaluation of micro hardness, colour stability and surface roughness, micro hardness testing machine, spectrophotometer and surface testing machine were used respectively. Initial and final readings were taken for each specimen and difference obtained was subjected to statistical analysis. One-way ANOVA was used for multiple group comparison followed by post-hoc Tukey's-test. The paried t-test was used for intra group comparison and unpaired t-test for comparing independent sample groups. The compomer and composite showed no significant difference in micro hardness either with conventional or whitening tooth paste both at two and four weeks. Although there was a highly significant colour change observed after using whitening tooth paste for both compomer and composite. Regarding surface roughness, there was a significant change in roughness in both conventional and whitening tooth paste with compomer and composite. However, whitening tooth paste had a significant change in surface roughness compared with conventional tooth paste

  12. Analysis of the relationship between the surface hardness and wear resistance of indirect composites used as veneer materials.

    Science.gov (United States)

    Faria, Adriana Cláudia Lapria; Benassi, Ubiratan Menezes; Rodrigues, Renata Cristina Silveira; Ribeiro, Ricardo Faria; Mattos, Maria da Gloria Chiarello de

    2007-01-01

    This study evaluated the surface hardness and wear resistance of indirect composites (Artglass and Solidex) and the existence of a correlation between these properties. Twenty-four specimens (12 per material) were fabricated using a polytetrafluoroethylene matrix (5.0 mm in diameter; 7.0 mm high) following an incremental technique. Polymerization was done with a xenon stroboscopic light curing unit. After polishing, the specimens were stored in water at 37 degrees C during either 1 day (n=6 per material) or 55 days (n=6 per material), after which Vickers surface hardness and wear resistance were assessed. Data were analyzed statistically by unpaired Student t-test, two-way ANOVA and Tukey's test. SURFACE HARDNESS: Artglass had higher surface hardness than Solidex after 1-day immersion period (pmaterials (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p0.05). WEAR RESISTANCE: Solidex had higher wear than Artglass after 1-day immersion period (pmaterials after 55 days (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p0.05). These results suggest that Artglass was better than Solidex in terms of hardness and wear resistance after 1-day water immersion. However, it was more susceptible to degradation, showing greater wear after 55 days. In conclusion, there was an inverse correlation between surface hardness and wear resistance for both Artglass and Solidex indirect composites, that is the higher the hardness, the lower the wear.

  13. The Role of Ruthenium in CO2 Capture and Catalytic Conversion to Fuel by Dual Function Materials (DFM

    Directory of Open Access Journals (Sweden)

    Shuoxun Wang

    2017-03-01

    Full Text Available Development of sustainable energy technologies and reduction of carbon dioxide in the atmosphere are the two effective strategies in dealing with current environmental issues. Herein we report a Dual Function Material (DFM consisting of supported sodium carbonate in intimate contact with dispersed Ru as a promising catalytic solution for combining both approaches. The Ru-Na2CO3 DFM deposited on Al2O3 captures CO2 from a flue gas and catalytically converts it to synthetic natural gas (i.e., methane using H2 generated from renewable sources. The Ru in the DFM, in combination with H2, catalytically hydrogenates both adsorbed CO2 and the bulk Na2CO3, forming methane. The depleted sites adsorb CO2 through a carbonate reformation process and in addition adsorb CO2 on its surface. This material functions well in O2- and H2O-containing flue gas where the favorable Ru redox property allows RuOx, formed during flue gas exposure, to be reduced during the hydrogenation cycle. As a combined CO2 capture and utilization scheme, this technology overcomes many of the limitations of the conventional liquid amine-based CO2 sorbent technology.

  14. The influence of milling-burnishing successive and simultaneous processes on the material hardness

    Science.gov (United States)

    Grigoraş, C. C.; Brabie, G.; Chirita, B.

    2016-08-01

    Recent developments in the field of bio-engineering allow the use of magnesium alloys as a substitute for medical implants. The issue with such alloys is the degradation rate witch has to be improved in order to provide the necessary support for the entire duration of the bone fraction healing. For improving the bone shielding heat treatment does not represent a solution, but chemical and/or mechanical do. One mechanical process that has excellent result is burnishing, but this process is difficult to be implemented on a milling machine. Therefore, it was necessary that a new tool and tool holder to be developed, that allow the simultaneous process to take place. A high-pressure hydraulic roller burnishing tool with a special tool holder was used on a CNC milling machine. The material used for this study is magnesium alloy AZ31B-F, and one of the main purposes was to improve the material hardness (HV). The milling-burnishing parameters that where varied are the speed and feed, burnishing pressure and depth, type of process (successive or simultaneous), machining direction and the material hardness after milling. The results were analyzed as percentage improvement between the milling and burnishing measured values.

  15. Surface roughness analysis after laser assisted machining of hard to cut materials

    Science.gov (United States)

    Przestacki, D.; Jankowiak, M.

    2014-03-01

    Metal matrix composites and Si3N4 ceramics are very attractive materials for various industry applications due to extremely high hardness and abrasive wear resistance. However because of these features they are problematic for the conventional turning process. The machining on a classic lathe still requires special polycrystalline diamond (PCD) or cubic boron nitride (CBN) cutting inserts which are very expensive. In the paper an experimental surface roughness analysis of laser assisted machining (LAM) for two tapes of hard-to-cut materials was presented. In LAM, the surface of work piece is heated directly by a laser beam in order to facilitate, the decohesion of material. Surface analysis concentrates on the influence of laser assisted machining on the surface quality of the silicon nitride ceramic Si3N4 and metal matrix composite (MMC). The effect of the laser assisted machining was compared to the conventional machining. The machining parameters influence on surface roughness parameters was also investigated. The 3D surface topographies were measured using optical surface profiler. The analysis of power spectrum density (PSD) roughness profile were analyzed.

  16. Kinetic simulations of core-hole relaxation in bulk material irradiated by hard X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Ziaja, Beata [Centre for Free-Electron Laser Science, DESY, Notkestrasse 85, Hamburg 22607 (Germany); Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Krakow (Poland); Saxena, Vikrant; Son, Sang-Kil; Medvedev, Nikita [Centre for Free-Electron Laser Science, DESY, Notkestrasse 85, Hamburg 22607 (Germany); Stransky, Michal [Department of Radiation and Chemical Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague (Czech Republic); Woloncewicz, Bianka [Faculty of Mathematics, Physics and Informatics, University of Gdansk, ul. Wita Stwosza 57, 80-952 Gdansk (Poland); Barbrel, Benjamin [Center for Intense Lasers and Applications, University of Bordeaux 1, 351 Cours de la Liberation, F-33405 Talence (France)

    2016-07-01

    Irradiation of bulk material by hard X-rays creates a non-equilibrium state characterized by the presence of core-hole states taking complicated relaxation paths towards ground state configurations. This relaxation process involves a large number of active configurations even in case of moderately heavy atoms (e.g., 1323 configurations for argon). It is computationally challenging to follow them, even with a kinetic approach which is otherwise an efficient approach for simulation of irradiated bulk material. Here, we propose a simplified approach which limits the number of active configurations by restricting the sample relaxation to the predominant relaxation paths. We test its reliability, by performing the full calculation for carbon, and comparing it with the simplified scheme.

  17. Tribological Investigations of Hard-Faced Layers and Base Materials of Forging Dies with Different Kinds of Lubricants Applied

    Directory of Open Access Journals (Sweden)

    V. Lazić

    2010-12-01

    Full Text Available This paper gives a procedure for choosing the right technology for reparative hard facing of damaged forging dies. Since they are subject to impact loads and cyclic temperature elevations, forging dies should be made of steel that is able to withstand great impact loads, maintain good mechanical properties at elevated temperatures and that is resistant to wear and thermal fatigue. For these reasons, forging dies are made of conditionally weldable alloy tool steels; however it makes hard facing of damaged tools even more difficult. In this paper, wear resistance of base materials, hard-faced layers and heat-affected zones are tribologically investigated when two different lubricants - pure synthetical oil LM 76 and LM 76 with 6% molybdenum disulfide (MoS2 are applied. Tribological investigations have shown that the wear resistance of the hard faced layers is considerably greater than the wear resistance of the base material. However, the base material has better properties concerning friction.

  18. Development of the hardness-gradient blade material by aluminum cladding; Arumikuraddo ni yoru keisha kodo hamono zairyo no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Imai, J.; Hamada, T.; Yamada, S.; Takegawa, Y. [Matsushita Electric Industrial Co. Ltd., Kadoma, Osaka (Japan)] Yamada, H. [Daido Steel Co. Ltd., Nagoya (Japan)

    1998-06-20

    Both high speed drive of a blade and sharpening of the edge of the blade are important for improving the cutting performance of a shaver. An elongation percentage of 20% or greater is requisite for processing the blade and a high surface hardness after heat treatment is necessary for sharpening the edge of the blade. Therefore, an object of this research is to develop a blade material wherein the base material hardness is similar to that of quenched steel of Hv=5GP or greater and the surface hardness is Hv=10GPa or greater. The surface and base material-hardened blade material is obtained by performing heat treatment after the processing of a material with Al applied as cladding to both sides of F3-13CR-2Mo martensite stainless steel. In this material, Al diffuses from the surface to the inside of the material, FeAl-based intermetallic compound is formed in the surface, thus the hardness decreases gradiently toward the inside of the material. When the above-described material is applied to a shaver, the edge of the blade can be sharpened to have a curve radius of or smaller than 1{mu}m, and therefore a blade material with excellent cutting performance is accomplished. 4 refs., 7 figs.

  19. Catalytic Ammonia Decomposition Over Ruthenium Nanoparticles Supported on Nano-Titanates

    DEFF Research Database (Denmark)

    Klerke, Asbjørn; Klitgaard, Søren Kegnæs; Fehrmann, Rasmus

    2009-01-01

    Nanosized Na2Ti3O7, K2Ti6O13 and Cs2Ti6O13 materials were prepared and used as supports of ruthenium nanoparticles for catalytic ammonia decomposition. It is shown that these catalysts exhibit higher catalytic activity than ruthenium supported on TiO2 nanoparticles promoted with cesium. The diffe...

  20. Iridium-Doped Ruthenium Oxide Catalyst for Oxygen Evolution

    Science.gov (United States)

    Valdez, Thomas I.; Narayan, Sri R.; Billings, Keith J.

    2011-01-01

    NASA requires a durable and efficient catalyst for the electrolysis of water in a polymer-electrolyte-membrane (PEM) cell. Ruthenium oxide in a slightly reduced form is known to be a very efficient catalyst for the anodic oxidation of water to oxygen, but it degrades rapidly, reducing efficiency. To combat this tendency of ruthenium oxide to change oxidation states, it is combined with iridium, which has a tendency to stabilize ruthenium oxide at oxygen evolution potentials. The novel oxygen evolution catalyst was fabricated under flowing argon in order to allow the iridium to preferentially react with oxygen from the ruthenium oxide, and not oxygen from the environment. Nanoparticulate iridium black and anhydrous ruthenium oxide are weighed out and mixed to 5 18 atomic percent. They are then heat treated at 300 C under flowing argon (in order to create an inert environment) for a minimum of 14 hours. This temperature was chosen because it is approximately the creep temperature of ruthenium oxide, and is below the sintering temperature of both materials. In general, the temperature should always be below the sintering temperature of both materials. The iridium- doped ruthenium oxide catalyst is then fabricated into a PEM-based membrane- electrode assembly (MEA), and then mounted into test cells. The result is an electrolyzer system that can sustain electrolysis at twice the current density, and at the same efficiency as commercial catalysts in the range of 100-200 mA/sq cm. At 200 mA/sq cm, this new system operates at an efficiency of 85 percent, which is 2 percent greater than commercially available catalysts. Testing has shown that this material is as stable as commercially available oxygen evolution catalysts. This means that this new catalyst can be used to regenerate fuel cell systems in space, and as a hydrogen generator on Earth.

  1. Imaging of soft and hard materials using a Boersch phase plate in a transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Alloyeau, D., E-mail: alloyeau.damien@gmail.com [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States); Hsieh, W.K. [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States); Anderson, E.H.; Hilken, L. [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley CA 94720 (United States); Benner, G. [Carl Zeiss NTS GmbH, Oberkochen 73447 (Germany); Meng, X. [Electrical Engineering and Computer Sciences, UC Berkeley, Berkeley, CA 94720-1770 (United States); Chen, F.R. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan (China); Kisielowski, C. [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States)

    2010-04-15

    Using two levels of electron beam lithography, vapor phase deposition techniques, and FIB etching, we have fabricated an electrostatic Boersch phase plate for contrast enhancement of weak phase objects in a transmission electron microscope. The phase plate has suitable dimensions for the imaging of small biological samples without compromising the high-resolution capabilities of the microscope. A micro-structured electrode allows for phase tuning of the unscattered electron beam, which enables the recording of contrast enhanced in-focus images and in-line holograms. We have demonstrated experimentally that our phase plate improves the contrast of carbon nanotubes while maintaining high-resolution imaging performance, which is demonstrated for the case of an AlGaAs heterostructure. The development opens a new way to study interfaces between soft and hard materials.

  2. High peak power solid-state laser for micromachining of hard materials

    Science.gov (United States)

    Herbst, Ludolf; Quitter, John P.; Ray, Gregory M.; Kuntze, Thomas; Wiessner, Alexander O.; Govorkov, Sergei V.; Heglin, Mike

    2003-06-01

    Laser micromachining has become a key enabling technology in the ever-continuing trend of miniaturization in microelectronics, micro-optics, and micromechanics. New applications have become commercially viable due to the emergence of innovative laser sources, such as diode pumped solid-state lasers (DPSSL), and the progress in processing technology. Examples of industrial applications are laser-drilled micro-injection nozzles for highly efficient automobile engines, or manufacturing of complex spinnerets for production of synthetic fibers. The unique advantages of laser-based techniques stem from their ability to produce high aspect ratio holes, while yielding low heat affected zones with exceptional surface quality, roundness and taper tolerances. Additionally, the ability to drill blind holes and slots in very hard materials such as diamond, silicon, sapphire, ceramics and steel is of great interest for many applications in microelectronics, semiconductor and automotive industry. This kind of high quality, high aspect ratio micromachining requires high peak power and short pulse durations.

  3. [Electrochemical properties of biocompatible material hardness modifications on titanium and steel under mechanical loads].

    Science.gov (United States)

    Braun, W; Walter, U; Holbein, R; Thull, R

    2005-04-01

    Friction corrosion may appear between different implant components or between implant and hard tissue. The sliding micro movements induce fretting wear corrosion and have been recently reported as a cause of joint prostheses failure. A surface coating is desirable, that retains the mechanical properties of the substrate, offers good biocompatibility and improves the fretting corrosion resistance. In this study it could be demonstrated that tantalum and niobium coatings fulfill the requirements. On titanium substrates the coating decreases the abrasion against PMMA, an orthopedic relevant material. Furthermore, in the case of medical steel substrates the biocompatibility and the corrosion properties are improved. The better abrasion-resistance is minimizing the release of allergological critical particles like nickel and chromium.

  4. The Effect of Arch Height and Material Hardness of Personalized Insole on Correction and Tissues of Flatfoot

    Directory of Open Access Journals (Sweden)

    Shonglun Su

    2017-01-01

    Full Text Available Flat foot is one of the common deformities in the youth population, seriously affecting the weight supporting and daily exercising. However, there is lacking of quantitative data relative to material selection and shape design of the personalized orthopedic insole. This study was to evaluate the biomechanical effects of material hardness and support height of personalized orthopedic insole on foot tissues, by in vivo experiment and finite element modeling. The correction of arch height increased with material hardness and support height. The peak plantar pressure increased with the material hardness, and these values by wearing insoles of 40° were apparently higher than the bare feet condition. Harder insole material results in higher stress in the joint and ligament stress than softer material. In the calcaneocuboid joint, the stress increased with the arch height of insoles. The material hardness did not apparently affect the stress in the ankle joints, but the support heights of insole did. In general, insole material and support design are positively affecting the correction of orthopedic insole, but negatively resulting in unreasonable stress on the stress in the joint and ligaments. There should be an integration of improving correction and reducing stress in foot tissues.

  5. Possibilities and Challenges of Scanning Hard X-ray Spectro-microscopy Techniques in Material Sciences

    Directory of Open Access Journals (Sweden)

    Andrea Somogyi

    2015-06-01

    Full Text Available Scanning hard X-ray spectro-microscopic imaging opens unprecedented possibilities in the study of inhomogeneous samples at different length-scales. It gives insight into the spatial variation of the major and minor components, impurities and dopants of the sample, and their chemical and electronic states at micro- and nano-meter scales. Measuring, modelling and understanding novel properties of laterally confined structures are now attainable. The large penetration depth of hard X-rays (several keV to several 10 keV beam energy makes the study of layered and buried structures possible also in in situ and in operando conditions. The combination of different X-ray analytical techniques complementary to scanning spectro-microscopy, such as X-ray diffraction, X-ray excited optical luminescence, secondary ion mass spectrometry (SIMS and nano-SIMS, provides access to optical characteristics and strain and stress distributions. Complex sample environments (temperature, pressure, controlled atmosphere/vacuum, chemical environment are also possible and were demonstrated, and allow as well the combination with other analysis techniques (Raman spectroscopy, infrared imaging, mechanical tensile devices, etc. on precisely the very same area of the sample. The use of the coherence properties of X-rays from synchrotron sources is triggering emerging experimental imaging approaches with nanometer lateral resolution. New fast analytical possibilities pave the way towards statistically significant studies at multi- length-scales and three dimensional tomographic investigations. This paper gives an overview of these techniques and their recent achievements in the field of material sciences.

  6. Special Issue on Ruthenium Complexes

    Directory of Open Access Journals (Sweden)

    Ileana Dragutan

    2017-02-01

    Full Text Available The organic chemistry of ruthenium has been one of the most vigorously growing research areas over the past decades. Considerable effort has been extended towards the design and application of a broad series of ruthenium complexes, which culminated with the development by Ryoji Noyori (2001 Nobel Prize for Chemistry of chiral ruthenium catalysts for stereoselective hydrogenation reactions [1], and the discovery by Robert H. Grubbs (2005 Nobel Prize for Chemistry of well-defined ruthenium– benzylidene catalysts for olefin metathesis [2] [...

  7. Effect of storage in water and thermocycling on hardness and roughness of resin materials for temporary restorations

    Directory of Open Access Journals (Sweden)

    Jerusa Cleci de Oliveira

    2010-09-01

    Full Text Available PURPOSE: This study evaluated the effect of storage in water and thermocycling on hardness and roughness of resin materials for temporary restorations. MATERIAL AND METHODS: Three acrylic resins (Dencor-De, Duralay-Du, and Vipi Cor-VC were selected and one composite resin (Opallis-Op was used as a parameter for comparison. The materials were prepared according to the manufacturers' instructions and were placed in stainless steel moulds (20 mm in diameter and 5 mm thick. Thirty samples of each resin were made and divided into three groups (n = 10 according to the moment of Vickers hardness (VHN and roughness (Ra analyses: C (control group: immediately after specimen preparation; Sw: after storage in distilled water at 37 °C for 24 hours; Tc: after thermocycling (3000 cycles; 5-55 °C, 30 seconds dwell time. Data were submitted to 2-way ANOVA followed by Tukey's test (α = 0.05. RESULTS: Op resin had higher surface hardness values (p 0.05 in roughness among materials (De = 0.31 ± 0.07; Du = 0.51 ± 0.20; VC = 0.41 ± 0.15; Op = 0.42 ± 0.18. Storage in water did not change hardness and roughness of the tested materials (p > 0.05. There was a significant increase in roughness after thermocycling (p < 0.05, except for material Du, which showed no significant change in roughness in any evaluated period (p = 0.99. CONCLUSION: Thermocycling increased the roughness in most tested materials without affecting hardness, while storage in water had no significant effect in the evaluated properties.

  8. Effective depth-of-penetration range due to hardness variation for different lots of nominally identical target material

    Directory of Open Access Journals (Sweden)

    Patrick Frueh

    2016-04-01

    A linear regression analysis of penetration vs. hardness shows that a target hardness increase within the given range of 280–330 BHN may result in a reduction of penetration depth of about 5.8 mm at constant velocity. This is equal to a change of −12% at an impact velocity of 1250 m/s. A multiple linear regression analysis included also the influence of yaw angle and impact velocity. It shows that small yaw angles and slight variations of impact velocities provide a smaller variation of the semi-infinite penetration depths than a variation of target hardness within a typical specification span of 50 BHN. For such a span a change in penetration of approximately −4.8 mm due to hardness variation is found, whereas 1° of yaw angle or −10 m/s of velocity variation gives a change of about −1.0 mm respectively −0.9 mm. For the given example, the overwhelming part of the variation is to be attributed to hardness effects – 4.8 mm out of 5.8 mm (83%. For nominally identical target material the target hardness thus influences the ballistic test results more severely than the typical scatter in impact conditions.

  9. Electron Tomography: A Three-Dimensional Analytic Tool for Hard and Soft Materials Research.

    Science.gov (United States)

    Ercius, Peter; Alaidi, Osama; Rames, Matthew J; Ren, Gang

    2015-10-14

    Three-dimensional (3D) structural analysis is essential to understand the relationship between the structure and function of an object. Many analytical techniques, such as X-ray diffraction, neutron spectroscopy, and electron microscopy imaging, are used to provide structural information. Transmission electron microscopy (TEM), one of the most popular analytic tools, has been widely used for structural analysis in both physical and biological sciences for many decades, in which 3D objects are projected into two-dimensional (2D) images. In many cases, 2D-projection images are insufficient to understand the relationship between the 3D structure and the function of nanoscale objects. Electron tomography (ET) is a technique that retrieves 3D structural information from a tilt series of 2D projections, and is gradually becoming a mature technology with sub-nanometer resolution. Distinct methods to overcome sample-based limitations have been separately developed in both physical and biological science, although they share some basic concepts of ET. This review discusses the common basis for 3D characterization, and specifies difficulties and solutions regarding both hard and soft materials research. It is hoped that novel solutions based on current state-of-the-art techniques for advanced applications in hybrid matter systems can be motivated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Potential of sago starch/carrageenan mixture as gelatin alternative for hard capsule material

    Science.gov (United States)

    Poeloengasih, Crescentiana Dewi; Pranoto, Yudi; Anggraheni, Frida Dwi; Marseno, Djagal Wiseso

    2017-03-01

    In order to replace gelatin in capsule shell production, blends of sago starch and carrageenan were developed. Films and capsules were prepared with 10% (w/v) of sago starch, 25% (w/w starch) of glycerol and various carrageenan concentration (1, 2, 3% w/w starch) in two different kappa/iota-carrageenan ratio (1:3 and 3:1). The resulted films and capsules were characterized by mechanical property, water vapor and oxygen permeability. In addition, moisture absorption and solubility of capsule in acid solution were investigated. The results reveal that addition of carrageenan makes the films stronger and less permeable. Higher kappa-carrageenan content improved tensile strength and barrier properties of the films, whereas higher iota-carrageenan content produced films with higher elongation, moisture absorption and capsule solubility in acid solution. Capsule with 2% (w/w starch) of carrageenan at kappa-/iota-ratio 3:1 had the lowest moisture absorption, whereas capsule with 3% (w/w starch) of carrageenan at kappa/iota ratio 1:3 had the highest solubility. It is illustrated that sago starch/carrageenan blends can be used as hard capsule material.

  11. An Experimental Technique for the Evaluation of Strain Dependent Material Properties of Hard Coatings

    Directory of Open Access Journals (Sweden)

    Shad A. Reed

    2008-01-01

    Full Text Available A novel vibration experiment consisting of a free-free boundary condition, an electromagnetic excitation source, a vacuum chamber, and a laser vibrometer based surface measurement system has been developed that permits high levels of excitation on highly damped specimens with a minimal amount of unwanted systematic error. While some of the aspects of this experiment are not unique, when combined with a processing technique that accounts for the nonlinearities present in the system, this experiment permits, accurate measurement of strain dependent stiffness and damping properties of hard coatings at high strain levels. This procedure has been demonstrated using a titanium beam that has been coated with a free-layer damping treatment of Magnesium Aluminate Spinel. The results indicate that Magnesium Aluminate Spinel has both nonlinear stiffness and damping properties. The stiffness asymptotes to a minimum value around 650 microstrain while the damping is a maximum around 100 microstrain. Additionally, the data contained herein cover a larger strain range for this material than previously reported.

  12. Effect of the addition of antimicrobial agents on Shore A hardness and roughness of soft lining materials.

    Science.gov (United States)

    Urban, Vanessa M; Lima, Thiago F; Bueno, Mirian G; Giannini, Marcelo; Arioli Filho, João N; de Almeida, Ana Lúcia P F; Neppelenbroek, Karin H

    2015-04-01

    While the incorporation of antimicrobial agents into soft denture liners has been suggested as a reliable alternative treatment for denture stomatitis, it may affect the liner's properties. The effect of addition of antimicrobial agents for the treatment of denture stomatitis on the surface roughness and Shore A hardness of soft lining materials was evaluated. The test groups comprised specimens (36 × 7 × 6 mm(3) ) of soft materials (Softone and Trusoft) without (control) or with incorporation of drugs (nystatin, miconazole, ketoconazole, chlorhexidine diacetate, and itraconazole). Hardness (Shore A) and roughness (Ra) were evaluated after immersion of specimens (n = 10) in distilled water at 37°C for 24 hours, 7 and 14 days. Data were analyzed by 3-way ANOVA/Tukey's test (α = 0.05). After 14 days, an increase (p hardness of soft materials with time for the modified specimens, except for itraconazole. Addition of drugs increased the Softone roughness only for the addition of miconazole and chlorhexidine (p hardness and roughness with time in the modified groups compared to controls were observed for itraconazole groups for both materials. © 2014 by the American College of Prosthodontists.

  13. Soluble Two-Dimensional Covalent Organometallic Polymers by (Arene)Ruthenium-Sulfur Chemistry.

    Science.gov (United States)

    Coraux, Johann; Hourani, Wael; Müller, Valentin L; Lamare, Simon; Kamaruddin, Danial Aiman; Magaud, Laurence; Bendiab, Nedjma; Den Hertog, Martien; Leynaud, Olivier; Palmino, Frank; Salut, Roland; Chérioux, Frédéric

    2017-08-16

    A class of two-dimensional (2D) covalent organometallic polymers, with nanometer-scale crosslinking, was obtained by arene(ruthenium) sulfur chemistry. Their ambivalent nature, with positively charged crosslinks and lypophylic branches is the key to the often sought-for and usually hard-to-achieve solubility of 2D polymers in various kinds of solvents. Solubility is here controlled by the planarity of the polymer, which in turn controls Coulomb interactions between the polymer layers. High planarity is achieved for high symmetry crosslinks and short, rigid branches. Owing to their solubility, the polymers are easily processable, and can be handled as powder, deposited on surfaces by mere spin-coating, or suspended across membranes by drop-casting. The novel 2D materials are potential candidates as flexible membranes for catalysis, cancer therapy, and electronics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Supercapacitive performance of hydrous ruthenium oxide (RuO2 ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 36; Issue 7. Supercapacitive performance of hydrous ruthenium oxide (RuO2.H2O) thin films synthesized by chemical route at low temperature. P R Deshmukh S N Pusawale R N Bulakhe C D Lokhande. Volume 36 Issue 7 December 2013 pp 1171-1176 ...

  15. Study on simple evaluation of mechanical properties of rock materials for Equotip hardness tester

    Science.gov (United States)

    Muramiya, Masaya; Yoshida, Hidenori; Tatsumi, Takakuni

    The mechanical properties of a rock or a soil are different in a narrow area. However, it is difficult to get their sample and to perform a various types of tests from the view points of time and economy. Thus, in this study, Equotip hardness test is focused. Because the test is easy to measure, it is possible to carry on the test at several points in a short time. Additionally, the cost performance of the test is excellent. In this article, the compression test for several artificial specimens is conducted, Equotip hardness test is also conducted before and after the compression test. Through the comparison between the measured data by the Equotip hardness test and the various properties, it turned out that the various properties can be presumed by Equotip hardness test.

  16. Effect of light-curing method and indirect veneering materials on the Knoop hardness of a resin cement

    Directory of Open Access Journals (Sweden)

    Nelson Tetsu Iriyama

    2009-06-01

    Full Text Available This study evaluated the Knoop hardness of a dual-cured resin cement (Rely-X ARC activated solely by chemical reaction (control group or by chemical / physical mode, light-cured through a 1.5 mm thick ceramic (HeraCeram or composite (Artglass disc. Light curing was carried out using conventional halogen light (XL2500 for 40 s (QTH; light emitting diodes (Ultrablue Is for 40 s (LED; and Xenon plasma arc (Apollo 95E for 3 s (PAC. Bovine incisors had their buccal face flattened and hybridized. On this surface a rubber mold (5 mm in diameter and 1 mm in height was bulk filled with the resin cement. A polyester strip was seated for direct light curing or through the discs of veneering materials. After dry storage in the dark (24 h 37°C, the samples (n = 5 were sectioned for hardness (KHN measurements, taken in a microhardness tester (50 gF load 15 s. The data were statistically analyzed by ANOVA and Tukey's test (α = 0.05. The cement presented higher Knoop hardness values with Artglass for QTH and LED, compared to HeraCeram. The control group and the PAC/Artglass group showed lower hardness values compared to the groups light-cured with QTH and LED. PAC/HeraCeram resulted in the worst combination for cement hardness values.

  17. Low-intensity lasers, modern filling materials, and bonding systems influence on mineral metabolism of hard dental tissues

    Science.gov (United States)

    Kunin, Anatoly A.; Yesaulenko, I. E.; Zoibelmann, M.; Pankova, Svetlana N.; Ippolitov, Yu. A.; Oleinik, Olga I.; Popova, T. A.; Koretskaya, I. V.; Shumilovitch, Bogdan R.; Podolskaya, Elana E.

    2001-10-01

    One of the main reasons of low quality filling is breaking Ca-P balance in hard tissues. Our research was done with the purpose of studying the influence of low intensity lasers, diodic radiation, the newest filling and bonding systems on the processes of mineral metabolism in hard dental tissues while filling a tooth. 250 patients having caries and its compli-cations were examined and treated. Our complex research included: visual and instrumental examination, finding out the level of oral cavity hygiene, acid enamel biopsy, scanning electronic microscopy and X-ray spectrum microanalysis. Filling processes may produce a negative effect on mineral metabolism of hard dental tissues the latter is less pronounced when applying fluoride-containing filling materials with bonding systems. It has also been found that bonding dentin and enamel systems are designed for both a better filling adhesion (i.e. mechanical adhesion) and migration of useful microelements present in them by their sinking into hard dental tissues (i.e. chemical adhesion). Our research showed a positive influence of low intensity laser and diodic beams accompanying the use of modern filling and bonding systems on mineral metabolism of hard dental tissues.

  18. Effect of ethanol in mouthwashes on the surface hardness of a dental resin composite material

    Directory of Open Access Journals (Sweden)

    Decky J. Indrani

    2009-03-01

    Full Text Available The previous study has shown that dental resins exhibited changes in the surface hardness when soaked in alcoholic beverages. As ethanol was one of the components contained in some commercial mouthwashes, therefore, the present study aimed at the effect of ethanol in some mouthwashes on the surface hardness of a dental resin composite. Specimens were prepared from a light cured dental resin composite. The specimens were then immersed in some commercial mouthwashes for periods up to 14 days. The surface hardness of the specimens was then measured using a Microhardness tester. The results displayed reductions in surface hardness (p<0,01, upon one day of immersing the specimens in Bactidol®, Listerine® or Minosepe® mouthwash, respectively. The surface hardness curves from each mouthwash demonstrated a similar pattern which approached a plateau near 2 weeks. It can be concluded that the ethanol-containing mouthwashes appeared to have more implication on surface hardness of the dental resin composite and the effect of immersing in the mouthwashes was time-dependent; it decreased sharply on the first day of immersion, however, further changes, did not exist.

  19. Continuous FEM simulation of the nanoindentation. Actual indenter tip geometries, material elastoplastic deformation laws and universal hardness

    Energy Technology Data Exchange (ETDEWEB)

    Bouzakis, K.D.; Michailidis, N.; Hadjiyiannis, S.; Skordaris, G. [Mechanical Engineering Dept., Aristoteles Univ. of Thessaloniki (Greece); Erkens, G. [CemeCon AG, Wuerselen (Germany)

    2002-09-01

    The precise knowledge of materials mechanical properties is always a core issue in every technical application. Through a developed finite elements method (FEM) continuous simulation of the nanoindentation, the applied force course versus the penetration depth is adequately simulated during the loading and unloading phases of this test, and the corresponding material stress-strain curves, as well as the universal hardness, are stepwise defined. Furthermore, the actual tip geometries of various indenters are approached and through equivalent magnitudes described. The results show that the defined material elastoplastic deformation characteristics are independent of the indenter type, as Vickers or Berkovich, since the existing indenter tip form deviations from their ideal geometry are considered. Furthermore, using the developed FEM-based nanoindentation simulation, the influence of the indenter tip geometry on the defined constitutive laws and the universal hardness is sufficiently elucidated. Various materials stress-strain curves and universal hardness courses versus the indentation depth, determined by means of the developed procedure, are presented. (orig.)

  20. Mechanical-plowing-based high-speed patterning on hard material via advanced-control and ultrasonic probe vibration

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhihua; Zou, Qingze, E-mail: qzzou@rci.rutgers.edu [Mechanical and Aerospace Engineering Department, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854 (United States); Tan, Jun; Jiang, Wei [Electrical and Computer Engineering Department, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854 (United States)

    2013-11-15

    In this paper, we present a high-speed direct pattern fabrication on hard materials (e.g., a tungsten-coated quartz substrate) via mechanical plowing. Compared to other probe-based nanolithography techniques based on chemical- and/or physical-reactions (e.g., the Dip-pen technique), mechanical plowing is meritorious for its low cost, ease of process control, and capability of working with a wide variety of materials beyond conductive and/or soft materials. However, direct patterning on hard material faces two daunting challenges. First, the patterning throughput is ultimately hindered by the “writing” (plowing) speed, which, in turn, is limited by the adverse effects that can be excited/induced during high-speed, and/or large-range plowing, including the vibrational dynamics of the actuation system (the piezoelectric actuator, the cantilever, and the mechanical fixture connecting the cantilever to the actuator), the dynamic cross-axis coupling between different axes of motion, and the hysteresis and the drift effects related to the piezoelectric actuators. Secondly, it is very challenging to directly pattern on ultra-hard materials via plowing. Even with a diamond probe, the line depth of the pattern via continuous plowing on ultra-hard materials such as tungsten, is still rather small (<0.5 nm), particularly when the “writing” speed becomes high. To overcome these two challenges, we propose to utilize a novel iterative learning control technique to achieve precision tracking of the desired pattern during high-speed, large-range plowing, and introduce ultrasonic vibration of the probe in the normal (vertical) direction during the plowing process to enable direct patterning on ultra hard materials. The proposed approach was implemented to directly fabricate patterns on a mask with tungsten coating and quartz substrate. The experimental results demonstrated that a large-size pattern of four grooves (20 μm in length with 300 nm spacing between lines) can be

  1. β-Type Zr-Nb-Ti biomedical materials with high plasticity and low modulus for hard tissue replacements.

    Science.gov (United States)

    Nie, Li; Zhan, Yongzhong; Hu, Tong; Chen, Xiaoxian; Wang, Chenghui

    2014-01-01

    In order to develop new biomedical materials for hard tissue replacements, Zr-20Nb-xTi (x=0, 3, 7, 11 and 15) alloys with required properties were designed and prepared by using the vacuum arc melting method for the first time. Phase analysis and microstructural observation showed that all the as cast samples consisted of equiaxed β-Zr phase. The mechanical properties and fracture behaviors of the Zr-20Nb-xTi alloys have been analyzed. It is found that these alloys exhibit high plasticity, moderate compressive strength (1044-1325MPa) and yield stress (854-1080MPa), high elastic energy (12-20MJ/m(3)) and low Young's modulus (28-31GPa). This good combination of mechanical properties makes them potential biomedical materials for hard tissue replacement. © 2013 Elsevier Ltd. All rights reserved.

  2. The Material Co-Construction of Hard Science Fiction and Physics

    Science.gov (United States)

    Hasse, Cathrine

    2015-01-01

    This article explores the relationship between hard science fiction and physics and a gendered culture of science. Empirical studies indicate that science fiction references might spur some students' interest in physics and help develop this interest throughout school, into a university education and even further later inspire the practice of…

  3. Surface effects of corrosive media on hardness, friction, and wear of materials

    Science.gov (United States)

    Miyoshi, K.; Buckley, D. H.; Rengstorff, G. W. P.; Ishigaki, H.

    1985-01-01

    Hardness, friction, and wear experiments were conducted with magnesium oxide exposed to various corrosive media and also with elemental iron and nickel exposed to water and NaOH. Chlorides such as MgCl2 and sodium containing films were formed on cleaved magnesium oxide surfaces. The MgCl2 films softened the magnesium oxide surfaces and caused high friction and great deformation. Hardness was strongly influenced by the pH value of the HCl-containing solution. The lower the pH, the lower the microhardness. Neither the pH value of nor the immersion time in NaOH containing, NaCl containing, and HNO3 containing solutions influenced the microhardness of magnesium oxide. NaOH formed a protective and low friction film on iron surfaces. The coefficient of friction and the wear for iron were low at concentrations of NaOH higher than 0.01 N. An increase in NaOH concentration resulted in a decrease in the concentration of ferric oxide on the iron surface. It took less NaOH to form a protective, low friction film on nickel than on iron.

  4. Exceptionally strong, stiff and hard hybrid material based on an elastomer and isotropically shaped ceramic nanoparticles.

    Science.gov (United States)

    Georgopanos, Prokopios; Schneider, Gerold A; Dreyer, Axel; Handge, Ulrich A; Filiz, Volkan; Feld, Artur; Yilmaz, Ezgi D; Krekeler, Tobias; Ritter, Martin; Weller, Horst; Abetz, Volker

    2017-08-04

    In this work the fabrication of hard, stiff and strong nanocomposites based on polybutadiene and iron oxide nanoparticles is presented. The nanocomposites are fabricated via a general concept for mechanically superior nanocomposites not based on the brick and mortar structure, thus on globular nanoparticles with nanosized organic shells. For the fabrication of the composites oleic acid functionalized iron oxide nanoparticles are decorated via ligand exchange with an α,ω-polybutadiene dicarboxylic acid. The functionalized particles were processed at 145 °C. Since polybutadiene contains double bonds the nanocomposites obtained a crosslinked structure which was enhanced by the presence of oxygen or sulfur. It was found that the crosslinking and filler percolation yields high elastic moduli of approximately 12-20 GPa and hardness of 15-18 GPa, although the polymer volume fraction is up to 40%. We attribute our results to a catalytically enhanced crosslinking reaction of the polymer chains induced by oxygen or sulfur and to the microstructure of the nanocomposite.

  5. Material erosion and erosion products under plasma heat loads typical for ITER hard disruptions

    Energy Technology Data Exchange (ETDEWEB)

    Safronov, V. E-mail: vsafr@rico.ttk.ru; Arkhipov, N.; Bakhtin, V.; Kurkin, S.; Scaffidi-Argentina, F.; Toporkov, D.; Vasenin, S.; Wuerz, H.; Zhitlukhin, A

    2001-03-01

    Plasma/material interaction has been studied in disruption simulation experiments. Candidate divertor materials were exposed to heat loads expected for tokamak-reactor disruptions. It is shown that sudden evaporation of a thin material layer produces a cloud of vapor plasma, which acts as a thermal shield protecting the surface from further excessive evaporation. In terms of evaporation reduction a shielding factor is above 100. Formation and physical properties of the shielding layer are analyzed. Target plasma converts the incoming energy flux into photon radiation. Radiation from target plasma is so intensive that it may cause erosion of nearby components. Surface damages result not solely from atomic vaporization but also from melt layer splashing for metals and brittle destruction for carbon-based materials. Erosion products are emitted as droplets (metal) and grains (carbon-based material). Melt layer splashing results in greater surface damages than vaporization. A contribution of brittle destruction to net erosion is under investigation now.

  6. New Coll–HA/BT composite materials for hard tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Zanfir, Andrei Vlad [Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Material Science, “Politehnica” University of Bucharest, 1-7 Gh. Polizu Street, RO-011061 Bucharest (Romania); Voicu, Georgeta, E-mail: getav2001@yahoo.co.uk [Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Material Science, “Politehnica” University of Bucharest, 1-7 Gh. Polizu Street, RO-011061 Bucharest (Romania); Busuioc, Cristina; Jinga, Sorin Ion [Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Material Science, “Politehnica” University of Bucharest, 1-7 Gh. Polizu Street, RO-011061 Bucharest (Romania); Albu, Madalina Georgiana [Department of Collagen, Branch of Leather and Footwear Research, National Institute of Research and Development for Textile and Leather, 93 I. Minulescu Street, RO-031215 Bucharest (Romania); Iordache, Florin [Department of Fetal and Adult Stem Cell Therapy, “Nicolae Simionescu” Institute of Cellular Biology and Pathology of Romanian Academy, 8 B.P. Hasdeu Street, RO-050568 Bucharest (Romania)

    2016-05-01

    The integration of ceramic powders in composite materials for bone scaffolds can improve the osseointegration process. This work was aimed to the synthesis and characterization of new collagen–hydroxyapatite/barium titanate (Coll–HA/BT) composite materials starting from barium titanate (BT) nanopowder, hydroxyapatite (HA) nanopowder and collagen (Coll) gel. BT nanopowder was produced by combining two wet-chemical approaches, sol–gel and hydrothermal methods. The resulting materials were characterized in terms of phase composition and microstructure by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. Moreover, the biocompatibility and bioactivity of the composite materials were assessed by in vitro tests. The synthesized BT particles exhibit an average size of around 35 nm and a spherical morphology, with a pseudo-cubic or tetragonal symmetry. The diffraction spectra of Coll–HA and Coll–HA/BT composite materials indicate a pronounced interaction between Col and the mineral phases, meaning a good mineralization of Col fibres. As well, the in vitro tests highlight excellent osteoinductive properties for all biological samples, especially for Coll–HA/BT composite materials, fact that can be attributed to the ferromagnetic properties of BT. - Highlights: • Collagen–hydroxyapatite/barium titanate composite materials were synthesized. • Barium titanate was produced by combining the sol–gel and hydrothermal methods. • The in vitro tests highlight excellent osteoinductive properties for all samples.

  7. New Coll-HA/BT composite materials for hard tissue engineering.

    Science.gov (United States)

    Zanfir, Andrei Vlad; Voicu, Georgeta; Busuioc, Cristina; Jinga, Sorin Ion; Albu, Madalina Georgiana; Iordache, Florin

    2016-05-01

    The integration of ceramic powders in composite materials for bone scaffolds can improve the osseointegration process. This work was aimed to the synthesis and characterization of new collagen-hydroxyapatite/barium titanate (Coll-HA/BT) composite materials starting from barium titanate (BT) nanopowder, hydroxyapatite (HA) nanopowder and collagen (Coll) gel. BT nanopowder was produced by combining two wet-chemical approaches, sol-gel and hydrothermal methods. The resulting materials were characterized in terms of phase composition and microstructure by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. Moreover, the biocompatibility and bioactivity of the composite materials were assessed by in vitro tests. The synthesized BT particles exhibit an average size of around 35 nm and a spherical morphology, with a pseudo-cubic or tetragonal symmetry. The diffraction spectra of Coll-HA and Coll-HA/BT composite materials indicate a pronounced interaction between Col and the mineral phases, meaning a good mineralization of Col fibres. As well, the in vitro tests highlight excellent osteoinductive properties for all biological samples, especially for Coll-HA/BT composite materials, fact that can be attributed to the ferromagnetic properties of BT. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

    Directory of Open Access Journals (Sweden)

    Ugur Erdemir

    2013-04-01

    Full Text Available Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group. For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05. Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001 in different solutions (p<0.001. The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (p<0.001. The compomer was the most affected by an acidic environment, whereas the composite resin materials were the least affected materials. Conclusions: The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

  9. Investigation on Effect of Material Hardness in High Speed CNC End Milling Process

    Directory of Open Access Journals (Sweden)

    N. V. Dhandapani

    2015-01-01

    Full Text Available This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the operator on floor is based on suggested values of the tool manufacturer or by trial and error method. This paper describes effect of various parameters on the surface roughness characteristics of the precision machining part. The prediction method suggested is based on various experimental analysis of parameters in different compositions of input conditions which would benefit the industry on standardization of high speed CNC end milling processes. The results show a basis for selection of parameters to get better results of surface roughness values as predicted by the case study results.

  10. Investigation on Effect of Material Hardness in High Speed CNC End Milling Process.

    Science.gov (United States)

    Dhandapani, N V; Thangarasu, V S; Sureshkannan, G

    2015-01-01

    This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the operator on floor is based on suggested values of the tool manufacturer or by trial and error method. This paper describes effect of various parameters on the surface roughness characteristics of the precision machining part. The prediction method suggested is based on various experimental analysis of parameters in different compositions of input conditions which would benefit the industry on standardization of high speed CNC end milling processes. The results show a basis for selection of parameters to get better results of surface roughness values as predicted by the case study results.

  11. Development of a New ATD-P Tester for Hard Wear Resistant Materials

    Directory of Open Access Journals (Sweden)

    Dojka M.

    2017-03-01

    Full Text Available The aim of presented studies was to develop a new geometry of the overflow part of standard ATD-C tester for derivative thermal analysis in a way that it would allow to obtain samples for abrasion and mechanical properties tests in the same mould without the need of cutting them from a block of material. The pattern of new ATD-P tester has parts reflecting implemented samples. Computer simulations regarding initial verification of new tester were performed in NovaFlow software. Chromium cast iron melts were made for testing the sampler in real conditions and TDA analysis for casting material were conducted. The sandmix was prepared on silica sand matrix per the ALPHASET technology. This new solution greatly simplifies the preparations of materials difficult to machine.

  12. Comparative study on structure, corrosion and hardness of Zn-Ni alloy deposition on AISI 347 steel aircraft material

    Energy Technology Data Exchange (ETDEWEB)

    Gnanamuthu, RM. [Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1732 Deogyeong-daero, Gihung, Yongin, Gyeonggi 446-701 (Korea, Republic of); Mohan, S., E-mail: sanjnamohan@yahoo.com [Central Electrochemical Research Institute, (CSIR), Karaikudi 630 006, Tamilnadu (India); Saravanan, G. [Central Electrochemical Research Institute, (CSIR), Karaikudi 630 006, Tamilnadu (India); Lee, Chang Woo, E-mail: cwlee@khu.ac.kr [Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1732 Deogyeong-daero, Gihung, Yongin, Gyeonggi 446-701 (Korea, Republic of)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Electrodeposition of Zn-Ni alloy on AISI 347 steel as an aircraft material has been carried out from various baths. Black-Right-Pointing-Pointer The effect of pulse duty cycle on thickness, current efficiency and hardness reached maximum values at 40% duty cycle and for 50 Hz frequencies average current density of 4 A dm{sup -2}. Black-Right-Pointing-Pointer The XRF characterizations of 88:12% Zn-Ni alloy provided excellent corrosion resistance. Black-Right-Pointing-Pointer It is found that Zn-Ni alloy on AISI 347 aircraft material has better structure and corrosion resistance by pulse electrodeposits from electrolyte-4. - Abstract: Zn-Ni alloys were electrodeposited on AISI 347 steel aircraft materials from various electrolytes under direct current (DCD) and pulsed electrodepositing (PED) techniques. The effects of pulse duty cycle on thickness, current efficiency and hardness of electrodeposits were studied. Alloy phases of the Zn-Ni were indexed by X-ray diffraction (XRD) techniques. Microstructural morphology, topography and elemental compositions were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray fluorescence spectroscopy (XRF). The corrosion resistance properties of electrodeposited Zn-Ni alloy in 3.5% NaCl aqueous solution obtained by DCD and PED were compared using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) technique. Elemental analysis showed that 88% of Zn and 12% of Ni obtained from electrolyte-4 by PED technique at 40% duty cycle for 50 Hz frequencies having better corrosion resistance than that of deposits obtained from other electrolytes.

  13. Prestressing Shock Resistant Mechanical Components and Mechanisms Made from Hard, Superelastic Materials

    Science.gov (United States)

    DellaCorte, Christopher (Inventor)

    2014-01-01

    A method and an apparatus confer full superelastic properties to the active surface of a mechanical component constructed of a superelastic material prior to service. A compressive load is applied to the active surface of the mechanical component followed by removing the compressive load from the active surface whereby substantially all load strain is recoverable after applying and removing of subsequent compressive loads.

  14. Cyclic Hardness Test PHYBALCHT: A New Short-Time Procedure to Estimate Fatigue Properties of Metallic Materials

    Science.gov (United States)

    Kramer, Hendrik; Klein, Marcus; Eifler, Dietmar

    Conventional methods to characterize the fatigue behavior of metallic materials are very time and cost consuming. That is why the new short-time procedure PHYBALCHT was developed at the Institute of Materials Science and Engineering at the University of Kaiserslautern. This innovative method requires only a planar material surface to perform cyclic force-controlled hardness indentation tests. To characterize the cyclic elastic-plastic behavior of the test material the change of the force-indentation-depth-hysteresis is plotted versus the number of indentation cycles. In accordance to the plastic strain amplitude the indentation-depth width of the hysteresis loop is measured at half minimum force and is called plastic indentation-depth amplitude. Its change as a function of the number of cycles of indentation can be described by power-laws. One of these power-laws contains the hardening-exponentCHT e II , which correlates very well with the amount of cyclic hardening in conventional constant amplitude fatigue tests.

  15. Manganese mono-boride, an inexpensive room temperature ferromagnetic hard material

    OpenAIRE

    Shuailing Ma; Kuo Bao; Qiang Tao; Pinwen Zhu; Teng Ma; Bo Liu; Yazhou Liu; Tian Cui

    2017-01-01

    We synthesized orthorhombic FeB-type MnB (space group: Pnma) with high pressure and high temperature method. MnB is a promising soft magnetic material, which is ferromagnetic with Curie temperature as high as 546.3?K, and high magnetization value up to 155.5?emu/g, and comparatively low coercive field. The strong room temperature ferromagnetic properties stem from the positive exchange-correlation between manganese atoms and the large number of unpaired Mn 3d electrons. The asymptotic Vickers...

  16. XRF intermediate thickness layer technique for analysis of residue of hard to dissolve materials

    Energy Technology Data Exchange (ETDEWEB)

    Mzyk, Z.; Mzyk, J.; Buzek, L. [Institute of Non-Ferrous Metals, Gliwice (Poland); Baranowska, I. [Department of Analytical and General Chemistry, Silesian Technical University, Gliwice (Poland)

    1998-12-31

    This work presents a quick method for lead and silver determination in materials, such as slags from silver metallurgy and slimes from copper electrorefining, which are very difficult to dissolve, even using a microwave technique. The idea was to dissolve the possibly greatest amount of the sample using acids. Insoluble deposit was filtered out. Silver content in the solution was analysed by potentiometric titration or AAS, lead content by XRS, while sediment deposit on filter - by XRF intermediate thickness technique. The results of silver and lead analysis obtained by this method were compared with those obtained by classical method, i.e. melting the residue with sodium peroxide. (author) 8 refs, 5 tabs

  17. Polymorphism and Elastic Response of Molecular Materials from First Principles: How Hard Can it Be?

    Science.gov (United States)

    Reilly, Anthony; Tkatchenko, Alexandre

    2014-03-01

    Molecular materials are of great fundamental and applied importance in science and industry, with numerous applications in pharmaceuticals, electronics, sensing, and catalysis. A key challenge for theory has been the prediction of their stability, polymorphism and response to perturbations. While pairwise models of van der Waals (vdW) interactions have improved the ability of density functional theory (DFT) to model these systems, substantial quantitative and even qualitative failures remain. In this contribution we show how a many-body description of vdW interactions can dramatically improve the accuracy of DFT for molecular materials, yielding quantitative description of stabilities and polymorphism for these challenging systems. Moreover, the role of many-body vdW interactions goes beyond stabilities to response properties. In particular, we have studied the elastic properties of a series of molecular crystals, finding that many-body vdW interactions can account for up to 30% of the elastic response, leading to quantitative and qualitative changes in elastic behavior. We will illustrate these crucial effects with the challenging case of the polymorphs of aspirin, leading to a better understanding of the conflicting experimental and theoretical studies of this system.

  18. A Next-Generation Hard X-Ray Nanoprobe Beamline for In Situ Studies of Energy Materials and Devices

    Energy Technology Data Exchange (ETDEWEB)

    Maser, Jong [Argonne National Lab. (ANL), Argonne, IL (United States); Lai, Barry [Argonne National Lab. (ANL), Argonne, IL (United States); Buonassisi, Toni [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Cai, Zhonghou [Argonne National Lab. (ANL), Argonne, IL (United States); Chen, Si [Argonne National Lab. (ANL), Argonne, IL (United States); Finney, Lydia [Argonne National Lab. (ANL), Argonne, IL (United States); Gleber, Sophie-Charlotte [Argonne National Lab. (ANL), Argonne, IL (United States); Jacobsen, Chris [Argonne National Lab. (ANL), Argonne, IL (United States); Preissner, Curt [Argonne National Lab. (ANL), Argonne, IL (United States); Roehrig, Chris [Argonne National Lab. (ANL), Argonne, IL (United States); Rose, Volker [Argonne National Lab. (ANL), Argonne, IL (United States); Shu, Deming [Argonne National Lab. (ANL), Argonne, IL (United States); Vine, David [Argonne National Lab. (ANL), Argonne, IL (United States); Vogt, Stefan [Argonne National Lab. (ANL), Argonne, IL (United States)

    2013-08-20

    The Advanced Photon Source is developing a suite of new X-ray beamlines to study materials and devices across many length scales and under real conditions. One of the flagship beamlines of the APS upgrade is the In Situ Nanoprobe (ISN) beamline, which will provide in situ and operando characterization of advanced energy materials and devices under varying temperatures, gas ambients, and applied fields, at previously unavailable spatial resolution and throughput. Examples of materials systems include inorganic and organic photovoltaic systems, advanced battery systems, fuel cell components, nanoelectronic devices, advanced building materials and other scientifically and technologically relevant systems. To characterize these systems at very high spatial resolution and trace sensitivity, the ISN will use both nanofocusing mirrors and diffractive optics to achieve spots sizes as small as 20 nm. Nanofocusing mirrors in Kirkpatrick–Baez geometry will provide several orders of magnitude increase in photon flux at a spatial resolution of 50 nm. Diffractive optics such as zone plates and/or multilayer Laue lenses will provide a highest spatial resolution of 20 nm. Coherent diffraction methods will be used to study even small specimen features with sub-10 nm relevant length scale. A high-throughput data acquisition system will be employed to significantly increase operations efficiency and usability of the instrument. The ISN will provide full spectroscopy capabilities to study the chemical state of most materials in the periodic table, and enable X-ray fluorescence tomography. In situ electrical characterization will enable operando studies of energy and electronic devices such as photovoltaic systems and batteries. We also describe the optical concept for the ISN beamline, the technical design, and the approach for enabling a broad variety of in situ studies. Furthermore, we discuss the application of hard X-ray microscopy to study defects in multi-crystalline solar

  19. A Study of Selected Properties and Applications of AlMgB14 and Related Composites: Ultra-Hard Materials

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Theron L. [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    This research presents a study of the hardness, electrical, and thermal properties AlMgB14 containing Al2MgO4 spinel. This research also investigated how much Al2MgO4 spinel consistently forms with AlMgB14, if AlMgB14 materials can be produced by hot isostatic pressing (HIP), what effects TiC and TiB2 have on this composite material, and the importance of mechanical alloying. Included also is a study of the variation in hardness measurements and how they relate to SI units. Heretofore, all ultra-hard materials (hardness > 40 GPA) have been found to be cubic in structure, electrical insulators, and expensive; the behavior of AlMgB14, which in certain specimens and compositions can have hardness values greater than 40 GPa, is therefore quite unusual since it is non-cubic, conductive, and moderate in cost. This offers an opportunity to investigate the relationship between hardness, thermal, and electrical properties from a new perspective. The main purpose of this project was to characterize the different properties of the AlMgB14 materials and to demonstrate that this material can be made in bulk. The technologies used for this study include microhardness measurement techniques, scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction spectroscopy, x-ray diffraction spectroscopy at different temperatures, optical microscopy, thermomechanical analysis, differential thermal analysis, 4-point probe resistivity, density techniques, Seebeck Effect, and Hall Effect. This research may lead to use of this material for applications where high abrasion resistance along with electrical conduction is needed. Also this research gave more information about a material that could have a great impact on industrial applications.

  20. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period.

    Science.gov (United States)

    Erdemir, Ugur; Yildiz, Esra; Eren, Meltem Mert; Ozel, Sevda

    2013-01-01

    This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05). Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (psports and energy drinks after a 1-month evaluation period (psports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

  1. In vitro evaluation of topical fluoride pH and their effect on surface hardness of composite resin-based restorative materials.

    Science.gov (United States)

    Mujeeb, Abdul; Mansuri, Samir; Hussain, Seema Abid; Ramaswamy, Kausar

    2014-03-01

    The aim of the study was to correlate the pH and fluoride ion uptake with surface hardness of composite resin based restorative materials after topical fluoride application. Forty disks of each of test materials Composite (Filtek Z350XT, 3M ESPE, St Paul, MN, USA), Resin modified glass ionomer (Vitremer) and Compomer (Dyract AP) were made and ten disks of each material were placed in different test solutions - 1.23% APF gel, Sodium fluoride mouth rinse, 0.9% neutral fluoride and distilled water (Control group). After 36 hours of immersion, specimens were subjected to microhardness testing machine for evaluation of surface hardness. The greater hardness deterioration for all materials resulted with 1.23% APF gel when compared to the control group. Composite (Filtek Z350XT, 3M ESPE, St Paul, MN, USA) showed 17.13 VHN (control group 59.11 VHN). Vitremer showed 9.71 VHN (control group 37.71 VHN). Compomer showed 19.22 VHN (control group 36.78 VHN). 1.23% ApF gel significantly decreased hardness of composite, Vitremer and Compomer. Hardness deterioration associated with sodium fluoride mouth rinse and 0.9% neutral fluoride was less compared to 1.23% ApF gel.

  2. The physical and mechanical properties and local deformation micromechanisms in materials with different dependence of hardness on the depth of print

    Science.gov (United States)

    Golovin, Yu. I.; Tyurin, A. I.; Aslanyan, E. G.; Pirozhkova, T. S.; Vasyukov, V. M.

    2017-09-01

    The size hardness effects are studied via the micro- and nanoindentation methods over the wide range of the depth of print h (from dozens of nanometers to several dozen micrometers) for several classes of materials, such as ionic and covalent single crystals (sapphire, silicon, lithium fluoride); metals (single-crystal Al, polycrystalline Cu, Ni, and Nb); ceramics (high-strength nanostructured TZP-ceramic based on the natural zirconium dioxide-baddeleyite mineral); amorphous materials (fused quartz); and polymers (polycarbonate and polytetrafluoroethylene). As is shown, some of them possess severe size hardness effects, whereas the others reveal the weak ones or even a lack of these effects. The thermoactivation analysis is implemented, as well, and the activating and energy characteristics of local deformation processes induced by an indenter are compared with the dominant plasticity micromechanisms of the studied materials at different stages of the print formation and with the size peculiarities. The materials with low hardness coefficients and meeting the requirements of ISO 14577 and GOST R 8.748-2011 standards in the nanohardness measurements are highlighted, as well. In the established load ranges, these materials are the promising candidates for their use as reference samples, which are designed to ensure the uniformity of the hardness measurements at the nano- and microscales, as well as for calibrating and testing the nanoindentometers.

  3. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

    Science.gov (United States)

    ERDEMİR, Ugur; YİLDİZ, Esra; EREN, Meltem Mert; OZEL, Sevda

    2013-01-01

    Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For the control groups, the specimens were stored in distilled water for 24 hours at 37º C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05). Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (phardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (phardness of a restorative material depends on the duration of exposure time, and the composition of the material. PMID:23739850

  4. Scaling laws for the mechanics of loose and cohesive granular materials based on Baxter's sticky hard spheres.

    Science.gov (United States)

    Gaume, Johan; Löwe, Henning; Tan, Shurun; Tsang, Leung

    2017-09-01

    We have conducted discrete element simulations (pfc3d) of very loose, cohesive, granular assemblies with initial configurations which are drawn from Baxter's sticky hard sphere (SHS) ensemble. The SHS model is employed as a promising auxiliary means to independently control the coordination number z_{c} of cohesive contacts and particle volume fraction ϕ of the initial states. We focus on discerning the role of z_{c} and ϕ for the elastic modulus, failure strength, and the plastic consolidation line under quasistatic, uniaxial compression. We find scaling behavior of the modulus and the strength, which both scale with the cohesive contact density ν_{c}=z_{c}ϕ of the initial state according to a power law. In contrast, the behavior of the plastic consolidation curve is shown to be independent of the initial conditions. Our results show the primary control of the initial contact density on the mechanics of cohesive granular materials for small deformations, which can be conveniently, but not exclusively explored within the SHS-based assembling procedure.

  5. Effect of chemical disinfection on the surface roughness of hard denture base materials: a systematic literature review.

    Science.gov (United States)

    Schwindling, Franz Sebastian; Rammelsberg, Peter; Stober, Thomas

    2014-01-01

    To assess the effect of chemical disinfection procedures on the surface roughness of hard denture base materials. A systematic literature review was conducted using five electronic databases (Medline, Cochrane Library, OpenGrey, Lilac, and Google Scholar) along with hand searching of the bibliographies of all located articles. The review yielded 193 articles. This number was reduced to 25 by using defined inclusion and exclusion criteria. Only one in vivo study was included; all others were in vitro evaluations. For every disinfecting agent, studies were found that reported surface alteration after chemical disinfection. The current literature suggests that changes in roughness might be more often associated with sodium perborate (three out of three studies with positive correlation) and less often with chlorhexidine digluconate and glutaraldehyde (two out of seven and one out of four studies with positive correlation, respectively). Because only single studies were found for glycine-type amphoteric surfactant solution, enzyme solution, ethanol, berberine hydrochloride, chlorine, reactive oxygen species, peracetic acid, cetylpyridinium chloride, and citric acid, no conclusions can be drawn about these disinfectants. Physical surface alteration is only one aspect when deciding on the use of chemical disinfection procedures. More research is needed to clarify whether these procedures can be recommended to patients.

  6. Effect of acidic food and drinks on surface hardness of enamel, dentine, and tooth-coloured filling materials.

    Science.gov (United States)

    Wongkhantee, S; Patanapiradej, V; Maneenut, C; Tantbirojn, D

    2006-03-01

    The purpose of this study was to determine the effect of acidic food and drinks (Cola soft drink, drinking yogurt, orange juice, sports drink, Tom-yum soup) on surface hardness of various substrates (enamel, dentine, universal composite, microfilled composite, conventional glass ionomer, resin-modified glass ionomer, polyacid-modified resin composite). Specimens (n = 10) were alternately immersed, 5 s each, in food or drinks and in artificial saliva for 10 cycles. Baseline and post-immersion Vickers hardness were compared using paired t-test. The difference in hardness between the groups was analysed with one-way ANOVA followed by a least significant different (LSD) test. Cola soft drink significantly reduced surface hardness of enamel, dentine, microfilled composite, and resin modified glass ionomer (p Tom-yum soup did not reduce surface hardness of any substrate. This in vitro study confirms the erosive potential of certain acidic food and drinks that public should be aware of.

  7. Ruthenium-Catalyzed Ammonia Borane Dehydrogenation: Mechanism and Utility.

    Science.gov (United States)

    Zhang, Xingyue; Kam, Lisa; Trerise, Ryan; Williams, Travis J

    2017-01-17

    One of the greatest challenges in using H2 as a fuel source is finding a safe, efficient, and inexpensive method for its storage. Ammonia borane (AB) is a solid hydrogen storage material that has garnered attention for its high hydrogen weight density (19.6 wt %) and ease of handling and transport. Hydrogen release from ammonia borane is mediated by either hydrolysis, thus giving borate products that are difficult to rereduce, or direct dehydrogenation. Catalytic AB dehydrogenation has thus been a popular topic in recent years, motivated both by applications in hydrogen storage and main group synthetic chemistry. This Account is a complete description of work from our laboratory in ruthenium-catalyzed ammonia borane dehydrogenation over the last 6 years, beginning with the Shvo catalyst and resulting ultimately in the development of optimized, leading catalysts for efficient hydrogen release. We have studied AB dehydrogenation with Shvo's catalyst extensively and generated a detailed understanding of the role that borazine, a dehydrogenation product, plays in the reaction: it is a poison for both Shvo's catalyst and PEM fuel cells. Through independent syntheses of Shvo derivatives, we found a protective mechanism wherein catalyst deactivation by borazine is prevented by coordination of a ligand that might otherwise be a catalytic poison. These studies showed how a bidentate N-N ligand can transform the Shvo into a more reactive species for AB dehydrogenation that minimizes accumulation of borazine. Simultaneously, we designed novel ruthenium catalysts that contain a Lewis acidic boron to replace the Shvo -OH proton, thus offering more flexibility to optimize hydrogen release and take on more general problems in hydride abstraction. Our scorpionate-ligated ruthenium species (12) is a best-of-class catalyst for homogeneous dehydrogenation of ammonia borane in terms of its extent of hydrogen release (4.6 wt %), air tolerance, and reusability. Moreover, a synthetically

  8. Development of a method for the preparation of ruthenium indenylidene-ether olefin metathesis catalysts.

    Science.gov (United States)

    Jimenez, Leonel R; Tolentino, Daniel R; Gallon, Benjamin J; Schrodi, Yann

    2012-05-11

    The reactions between several derivatives of 1-(3,5-dimethoxyphenyl)-prop-2-yn-1-ol and different ruthenium starting materials [i.e., RuCl₂(PPh₃)₃ and RuCl₂(p-cymene)(L), where L is tricyclohexylphosphine di-t-butylmethylphosphine, dicyclohexylphenylphosphine, triisobutylphosphine, triisopropylphosphine, or tri-n-propylphosphine] are described. Several of these reactions allow for the easy, in-situ and atom-economic preparation of olefin metathesis catalysts. Organic precursor 1-(3,5-dimethoxyphenyl)-1-phenyl-prop-2-yn-1-ol led to the formation of active ruthenium indenylidene-ether complexes, while 1-(3,5-dimethoxyphenyl)-prop-2-yn-1-ol and 1-(3,5-dimethoxyphenyl)-1-methyl-prop-2-yn-1-ol did not. It was also found that a bulky and strong σ-donor phosphine ligand was required to impart good catalytic activity to the new ruthenium complexes.

  9. Amorphous carbon nanofibres inducing high specific capacitance of deposited hydrous ruthenium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Barranco, V. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas (CSIC), Sor Juan Ines de la Cruz 3, Cantoblanco, E-28049-Madrid (Spain); Pico, F.; Ibanez, J. [Centro Nacional de Investigaciones Metalurgicas, CSIC, Avda. Gregorio del Amo 8, E-28040-Madrid (Spain); Lillo-Rodenas, M.A.; Linares-Solano, A. [MCMA, Departamento de Quimica Inorganica, Universidad de Alicante, P.O. Box 99, E-03080-Alicante (Spain); Kimura, M. [Gun Ei Chemical Ind. Co., Ltd., Takasaki, Gunma 370 (Japan); Oya, A. [Faculty of Engineering, Gunma University, Gunma 376 (Japan); Rojas, R.M.; Amarilla, J.M. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas (CSIC), Sor Juan Ines de la Cruz 3, Cantoblanco, E-28049-Madrid (Spain); Rojo, J.M., E-mail: jmrojo@icmm.csic.e [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas (CSIC), Sor Juan Ines de la Cruz 3, Cantoblanco, E-28049-Madrid (Spain)

    2009-12-01

    Composites consisting of ruthenium oxide particles deposited on amorphous carbon nanofibres are prepared by a repetitive impregnation procedure. The choice of amorphous carbon nanofibres as support of amorphous ruthenium oxide leads to composites in which the deposited oxide consists of aggregates of extremely small primary particles (1-1.5 nm-size) and showing high porosity (specific surface area of 450 m{sup 2} g{sup -1}). This special deposition of the oxide seems to favour: (i) high oxide capacitance (1000 Fg{sup -1}) at high oxide loadings (up to 20 wt%) and (ii) high capacitance retention (ca. 80% from the initial oxide capacitance) at high current densities (200 mA cm{sup -2}). Amorphous carbon nanofibres are suitable supports for amorphous ruthenium oxide and perhaps for other amorphous oxides acting as active electrode materials.

  10. Preheating of resin-based flowable materials in a microwave device: a promising approach to increasing hardness and softening resistance under cariogenic challenge.

    Science.gov (United States)

    Borges, Boniek Castillo; Barreto, Adrielle Silva; Gomes, Cláudia Lobelli; Silva, Talles Rodrigo; Alves-Júnior, Clodomiro; Pinheiro, Isauremi Vieira; Braz, Rodivan; Montes, Marcos Antonio

    2013-01-01

    This study aimed to evaluate whether preheated resin-based flowable restoratives would show increased hardness and softening susceptibility after an early cariogenic challenge. Fluroshield- Yellowed, Bioseal, Wave, Master Flow, Fluroshield-White, Conseal F, Filtek Z350 Flow, and Opallis Flow were tested. Preheating was performed using a microwave device. Five specimens of each preheated or room temperature material (n = 5) were fabricated. Hardness was assessed before and after a cariogenic challenge. The analysis was done by two-way analysis of variance (ANOVA) with repeated measures (cariogenic challenge) and Tukey's test for multiple comparisons (

  11. Graphene/Ruthenium Active Species Aerogel as Electrode for Supercapacitor Applications

    Science.gov (United States)

    Gigot, Arnaud; Fontana, Marco; Pirri, Candido Fabrizio; Rivolo, Paola

    2017-01-01

    Ruthenium active species containing Ruthenium Sulphide (RuS2) is synthesized together with a self-assembled reduced graphene oxide (RGO) aerogel by a one-pot hydrothermal synthesis. Ruthenium Chloride and L-Cysteine are used as reactants. The hydrothermal synthesis of the innovative hybrid material occurs at 180 °C for 12 h, by using water as solvent. The structure and morphology of the hybrid material are fully characterized by Raman, XRD, XPS, FESEM and TEM. The XRD and diffraction pattern obtained by TEM display an amorphous nanostructure of RuS2 on RGO crystallized flakes. The specific capacitance measured in planar configuration in 1 M NaCl electrolyte at 5 mV s−1 is 238 F g−1. This supercapacitor electrode also exhibits perfect cyclic stability without loss of the specific capacitance after 15,000 cycles. In summary, the RGO/Ruthenium active species hybrid material demonstrates remarkable properties for use as active material for supercapacitor applications. PMID:29301192

  12. Hexagonal-structured ε-NbN: ultra-incompressibility, high shear rigidity, and a possible hard superconducting material

    Science.gov (United States)

    Zou, Yongtao; Wang, Xuebing; Chen, Ting; Li, Xuefei; Qi, Xintong; Welch, David; Zhu, Pinwen; Liu, Bingbing; Cui, Tian; Li, Baosheng

    2015-01-01

    Exploring the structural stability and elasticity of hexagonal ε-NbN helps discover correlations among its physical properties for scientific and technological applications. Here, for the first time, we measured the ultra-incompressibility and high shear rigidity of polycrystalline hexagonal ε-NbN using ultrasonic interferometry and in situ X-ray diffraction, complemented with first-principles density-functional theory calculations up to 30 GPa in pressure. Using a finite strain equation of state approach, the elastic bulk and shear moduli, as well as their pressure dependences are derived from the measured velocities and densities, yielding BS0 = 373.3(15) GPa, G0 = 200.5(8) GPa, ∂BS/∂P = 3.81(3) and ∂G/∂P = 1.67(1). The hexagonal ε-NbN possesses a very high bulk modulus, rivaling that of superhard material cBN (B0 = 381.1 GPa). The high shear rigidity is comparable to that for superhard γ-B (G0 = 227.2 GPa). We found that the crystal structure of transition-metal nitrides and the outmost electrons of the corresponding metals may dominate their pressure dependences in bulk and shear moduli. In addition, the elastic moduli, Vickers hardness, Debye temperature, melting temperature and a possible superconductivity of hexagonal ε-NbN all increase with pressures, suggesting its exceptional suitability for applications under extreme conditions. PMID:26028439

  13. Reaction and photometric determination of ruthenium with dithizone

    Energy Technology Data Exchange (ETDEWEB)

    Roebisch, G.; Dietel, R. (Paedagogische Hochschule Karl Liebknecht, Potsdam (German Democratic Republic). Sektion Chemie/Biologie)

    1984-01-01

    Dithizone reacts with ruthenium(VIII or VI) at 20deg C, with inert ruthenium(IV)-complexes at 85deg C, to form a primary 1 : 3-dithizonate, which can by concentrated (20 fould) by extraction into chloroform. Based on this reaction, three variants of a reproducible and selective photometric determination of ruthenium traces (5 ppb) with dithizone has been developed.

  14. Radiation hardness of silicon detectors manufactured on epitaxial material and FZ bulk enriched with oxygen, carbon, tin and platinum

    CERN Document Server

    Ruzin, A; Glaser, M; Lemeilleur, F; Talamonti, R; Watts, S; Zanet, A

    1999-01-01

    Recent results on the radiation hardness of silicon detectors fabricated on epitaxial and float zone bulk silicon enriched by various impurities, such as carbon, oxygen, tin and platinum are reported. A new methodology of measurements of electrical properties of the devices has been utilized in the experiment. It has been shown that in the case of irradiation by protons, oxygen enriched silicon has better radiation hardness than standard float zone silicon. The carbon enriched silicon detectors, on the other hand, exhibited significantly inferior radiation hardness compared to standard detectors. This study shows for the first time, a violation of the widely used normalization technique of the various particle irradiations by NIEL coefficients. The study has been carried out in the framework of the RD48 (ROSE) collaboration, which studies the radiation hardening of silicon detectors. (5 refs).

  15. The influence of hard segment content on mechanical and thermal properties of polycarbonate-based polyurethane materials

    Directory of Open Access Journals (Sweden)

    Budinski-Simendić Jaroslava

    2012-01-01

    Full Text Available Aliphatic segmented polyurethanes were prepared by one-step procedure in catalytic reaction between polycarbonate diol, hexamethylene-diisocyanate and 1,4-butandiol (as chain extender. The hard segment content TS was varied (17, 24, 30 and 42 wt. % by changing the ratio of starting compounds. The soft segment is made from flexible aliphatic polycarbonate diol, while hard segments consist of chain extender and diisocyanate component. In order to study the hydrogen bonding formation and phase separation, Fourier transform infrared spectroscopy (FT-IR was used. Wide angle X-ray scattering (WAXS was performed to determine a degree of crystallinity and to investigate the phase behavior of prepared elastomers. The effect of TS content on mechanical properties (tensile strength, elongation at break and hardness was tested. Thermal behavior of prepared novel polycarbonate-based polyurethanes was investigated using differential scanning callorimetry (DSC. It was determined that the elastomer which contains the highest amount of urethane groups in its structure (TS content of 42 wt. % exhibits the most pronounced phase separation and the highest degree of crystallinity. All prepared polyurethanes exhibit high elongation at break (over 700%. The glass transition temperature Tg of prepared samples was in the temperature region from −39 to −36°C, and it was found to be slightly influenced by the soft segment content. The enthalpy of chain segments relaxation in diffused region between hard and soft domains (detected in the temperature range from 35 to 55 °C was decreased with the increase of hard segment content. The multiple melting of hard segments (connected with the dissruption of physical crosslinks appeared above 100 °C. It was found that the melting enthalpy linearly increases with the increase of urethane group content. Sample with 42 wt. % of TS has the highest value of melting enthalpy (41.5 J/g.

  16. Evaluation of radiation effects on dental enamel hardness and dental restorative materials; Avaliacao do efeito da irradiacao na dureza do esmalte dental e de materiais odontologicos

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Lena Katekawa; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radioquimica; Campos, Tomie Nakakuki [Sao Paulo Univ., SP (Brazil). Faculdade de Odontologia. Dept. de Protese

    2000-07-01

    This research presents the results of the microhardness of human dental enamel and of the following dental restorative materials: three dental porcelains - Ceramco II, Finesse and Noritake, and two resin restorative materials - Artglass and Targis, for materials submitted to different times of irradiation at the IEA-R1m nuclear reactor under a thermal neutron flux of 10{sup 12}n cm{sup -2}.s{sup -1} . The results obtained indicated that there is a decrease of the surface microhardness when the enamel is irradiated for 1 h and when dental materials are irradiated for 3 h. However, enamels irradiated for 30 min. did not show significant change of their surface hardness. Therefore, the selection of irradiation time is an important factor to be considered when irradiated teeth or dental materials are used in the investigations of their properties. (author)

  17. Optical constants in the hard X-ray/Soft gamma ray range of selected materials for multilayer reflectors

    DEFF Research Database (Denmark)

    Cooper-Jensen, Carsten P.; Romaine, S.; Bruni, R.

    2007-01-01

    Future Astrophysics missions operating in the hard X-ray/Soft Gamma ray range is slated to carry novel focusing telescopes based on the use of depth graded multilayer reflectors. Current design studies show that, at the foreseen focal lengths, it should be feasible to focus X-rays at energies...

  18. Optical nonlinearity, limiting and switching characteristics of novel ruthenium metal-organic complex

    Science.gov (United States)

    Manjunatha, K. B.; Rajarao, Ravindra; Umesh, G.; Ramachandra Bhat, B.; Poornesh, P.

    2017-10-01

    We report the nonlinear optical properties of Ruthenium metal complex a promising organic material for use in scientific and technological applications. The thin films of newly synthesized ruthenium metal-organic complex were fabricated using spin coating technique. Z-scan and degenerate four wave mixing (DFWM) techniques used to extract the third-order nonlinear optical (NLO) parameters. The data reveals the investigated material exhibited relatively large NLO properties. The pump-probe experiments shows that the switch-on and off times of the material were in the order of μs at different pump intensities and the energy dependent transmission studies reveal good limiting property of the material in nanosecond regime.

  19. Alcohol Dehydrogenation with a Dual Site Ruthenium, Boron Catalyst Occurs at Ruthenium

    Directory of Open Access Journals (Sweden)

    Denver Guess

    2012-10-01

    Full Text Available The complex [(κ3-(N,N,O-py2B(MeOHRu(NCMe3]+ TfO− (1 is a catalyst for transfer dehydrogenation of alcohols, which was designed to function through a cooperative transition state in which reactivity was split between boron and ruthenium. We show here both stoichiometric and catalytic evidence to support that in the case of alcohol oxidation, the mechanism most likely involves reactivity only at the ruthenium center.

  20. Effect of tempering on hardness improvement in a VC/steel surface-alloyed material fabricated by high-energy electron-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Euh, Kwangjun; Kim, Yong Chan; Shin, Keesam; Lee, Sunghak; Kim, Nack J

    2003-04-15

    The present study is concerned with the tempering effect in improving the hardness of a vanadium carbide (VC)/carbon steel surface-alloyed material fabricated by high-energy electron-beam irradiation. The mixture of VC powders and flux (50%MgO-50%CaO) was placed on a plain carbon steel substrate, and then electron beam was irradiated. The surface-alloyed layer of 1.8 mm in thickness was homogeneously formed without defects. The microstructural analysis indicated that coarse VC particles were formed along solidification cell boundaries, and the matrix inside cells was mostly composed of lath-type martensite and fine cuboidal VC particles. A large amount of these VC particles in the lath-type martensitic matrix provided hardness four times greater than that of the substrate. When the VC/steel surface-alloyed material was tempered, fine VC particles precipitated in the tempered martensitic matrix, thereby leading to additional hardness increase. In addition, reduction of residual stress and an increase in fracture toughness could be expected.

  1. The Hardness of Boride Layer on the S45C Iron (A preliminary study on surface hardening of ferrous material

    Directory of Open Access Journals (Sweden)

    Sutrisno

    2012-08-01

    Full Text Available The property such as microhardness of boride layer formed on S45C iron was investigated. Boronizing was carried out in a solid medium consisting of nano size powders of 50% B4C as a donor, 45% SiC as a diluent, and 5% KBF4 as an activator treated at the temperature of 10000C for 8 hours. The phases that were formed on the substrate was found as Fe2B and FeB layer that had smooth and flate shape morphology. The hardness of boride layer on S45C was over 2000 HV, while the hardness of untreated S45C iron was about 196,39 HV. Depending on process time and temperature, the depth of boride layer ranges from 25 to 55 µm, leading to a diffusion controlled process

  2. Preliminary assessment of modified borosilicate glasses for chromium and ruthenium immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Farid, Osama M. [Reactors Department, Nuclear Research Center, Atomic Energy Authority of Egypt, P.O. 13759, Inshas, Cairo (Egypt); Centre of Nuclear Engineering (CNE), Department of Materials, Imperial College London, London, SW7 2BP (United Kingdom); Abdel Rahman, R.O., E-mail: alaarehab@yahoo.com [Hot Laboratory Center, Atomic Energy Authority of Egypt, P.O. 13759, Inshas, Cairo (Egypt)

    2017-01-15

    The feasibility of using modified alkali borosilicate glasses for ruthenium and chromium immobilization is preliminary assessed by investigating the immobilization system structure under normal conditions. Within this context, reference alkali borosilicate, and simulated Magnox-modified glasses were prepared and studied. The results indicate that ruthenium is immobilized in the vitreous structure as encapsulated RuO{sub 2} crystallites that act as seeds for heterogeneous nucleation of other crystalline phases. The presence of Zn, as modifier, has contributed to chromium immobilization in zincochromite spinel structure, whereas Ca is accommodated in the vitreous structure. Immobilization performance was evaluated by conducting conservative static leach test and studying the leached glass. Leached glass morphology was altered, where near surface reference glass is leached over 400 nm and simulated Magnox-modified sample is altered over 300 nm. Normalized release rates are within normal range for borosilicate material. For simulated Magnox-modified sample, Ca and alkali structural element, i.e. Na and Li, are leached via ion-exchange reaction. The ion-exchanged fraction equals 1.06 × 10{sup −8} mol/m{sup 2} s and chromium has slightly lower normalized release rate value than ruthenium. - Highlights: • The presence of modifiers and waste oxides led to localized de-vitrification. • Ruthenium is encapsulated within the vitreous glass network as RuO{sub 2} crystals. • Chromium is immobilized within the zincochromite spinel structure. • Pitting and cracks induced by leaching did not affect the immobilization performance.

  3. Cyclometallated ruthenium (II) carbonyl complexes with 1 ...

    Indian Academy of Sciences (India)

    A facile method for the synthesis of a series of cyclometallated ruthenium(II) carbonyl complexes with 1-pyrenaldehyde 4-R-3-thiosemicarbazones (H2Ln where the two H's represent the dissociable thioamide and pyrenyl protons; R = H, Me and Ph) has been described. The characterization of the complexes having the ...

  4. Enyne Metathesis Catalyzed by Ruthenium Carbene Complexes

    DEFF Research Database (Denmark)

    Poulsen, Carina Storm; Madsen, Robert

    2003-01-01

    Enyne metathesis combines an alkene and an alkyne into a 1,3-diene. The first enyne metathesis reaction catalyzed by a ruthenium carbene complex was reported in 1994. This review covers the advances in this transformation during the last eight years with particular emphasis on methodology...

  5. Crystal Indentation Hardness

    Directory of Open Access Journals (Sweden)

    Ronald W. Armstrong

    2017-01-01

    Full Text Available There is expanded interest in the long-standing subject of the hardness properties of materials. A major part of such interest is due to the advent of nanoindentation hardness testing systems which have made available orders of magnitude increases in load and displacement measuring capabilities achieved in a continuously recorded test procedure. The new results have been smoothly merged with other advances in conventional hardness testing and with parallel developments in improved model descriptions of both elastic contact mechanics and dislocation mechanisms operative in the understanding of crystal plasticity and fracturing behaviors. No crystal is either too soft or too hard to prevent the determination of its elastic, plastic and cracking properties under a suitable probing indenter. A sampling of the wealth of measurements and reported analyses associated with the topic on a wide variety of materials are presented in the current Special Issue.

  6. Hard template synthesis of porous carbon nitride materials with improved efficiency for photocatalytic CO{sub 2} utilization

    Energy Technology Data Exchange (ETDEWEB)

    Ovcharov, M. [L.V Pysarzhevsky Institute of Physical Chemistry, NAS of Ukraine, 31 pr. Nauky, 03028 Kyiv (Ukraine); Shcherban, N., E-mail: nataliyalisenko@ukr.net [L.V Pysarzhevsky Institute of Physical Chemistry, NAS of Ukraine, 31 pr. Nauky, 03028 Kyiv (Ukraine); Filonenko, S.; Mishura, A. [L.V Pysarzhevsky Institute of Physical Chemistry, NAS of Ukraine, 31 pr. Nauky, 03028 Kyiv (Ukraine); Skoryk, M. [NanoMedTech LLC, 68 Gorkogo str., Kyiv (Ukraine); Shvalagin, V.; Granchak, V. [L.V Pysarzhevsky Institute of Physical Chemistry, NAS of Ukraine, 31 pr. Nauky, 03028 Kyiv (Ukraine)

    2015-12-15

    Graphical abstract: - Highlights: • Porous carbon nitrides were obtained via bulk and matrix pyrolysis of melamine. • Carbon nitride obtained in MCF has the highest bandgap and photocatalytic activity. • Acetaldehyde was the major product of the photoreduction reaction of CO2. - Abstract: Porous carbon nitrides of different morphology were obtained via bulk and hard template (SBA-15 and MCF) pyrolysis of melamine. Matrix method allowed obtaining ordered porous C{sub 3}N{sub 4} with higher bandgap (2.87 eV) in the contrary to the bulk sample (2.45 eV). Obtained carbon nitrides were found to be p-type semiconductors with catalytic activity towards photoreduction of carbon dioxide with water vapour. Carbon nitride obtained in MCF has the higher bandgap, developed surface, sponge-like morphology, spatially ordering and it's characterized by the highest photocatalytic activity.

  7. Investigation of corrosion and wear mechanisms in hard material-reinforced duplex steel coatings; Untersuchungen zum Korrosions- und Verschleissverhalten von hartstoffverstaerkten `Duplex`-Schutzschichten. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bouaifi, B. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Schweisstechnik und Trennende Fertigungsverfahren; Goellner, J. [Technische Univ. Magdeburg (Germany). Inst. fuer Werkstofftechnik und Werkstoffpruefung

    1998-09-30

    The hard-material reinforced duplex steel coatings were deposited by plasma arc two-powder surfacing. By varying the angle of the hard materials feeding process, the deposition of the carbides was optimized so that they are deposited into the matrix in the trailing zone of the welding torch under conditions of very low thermal effects near the freezing point of the weld pool. Microstructural studies revealed that the deposition of the hard materials prevents devlopment of the typical, ferritic-austenitic microstructure of duplex steels. Due to a dissolution and diffusion process, the microstructure of the matrix takes up carbon and chromium or tungsten, depending on the carbide, thus enhancing the austenitic material in the microstructure. The wear behaviour of the surface deposits was found to be very good, wear being reduced by a factor of 6, irrespective of the type of carbide. The friction-affected surfaces showed no dissolving effects or cracking. The corrosion behaviour in sulfuric acid is also good. The welded deposits exhibited the typical behaviour of a passive material. Wear mechanisms slightly reduce the resistance. The behaviour of various specimens in artificial seawater could be distinctly assessed. Small grain fractions and pre-heating temperatures of 100 C have a beneficial effect on the corrosion resistance. The technique recommends itself for applications such as coatings for baffle plates used in flue gas desulfurisation, pipes, pump components, flanges or nozzles, or for recurrent coating of system components affected by abrasive corrosion. (orig./CB) [Deutsch] Zur Herstellung hartstoffverstaerkter Duplex-Beschichtungen wurde das Plasma-Zwei-Pulver-Auftragschweissverfahren verwendet. Hierbei wurde durch Variation des Zufuhrwinkels der Hartstoffe der Einbringungsort der Karbide optimiert, so dass diese im Nachlauf des Schweissbrenners mit sehr geringer thermischer Beeinflussung im erstarrungsnahen Schmelzbadbereich in die Matrix eingelagert

  8. Selective Aerobic Oxidation of 5-Hydroxymethylfurfural in Water Over Solid Ruthenium Hydroxide Catalysts with Magnesium-Based Supports

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Riisager, Anders

    2011-01-01

    Solid catalyst systems comprised of ruthenium hydroxide supported on magnesium-based carrier materials (spinel, magnesium oxide and hydrotalcite) were investigated for the selective, aqueous aerobic oxidation of the biomass-derived chemical 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid...

  9. Platinum adlayered ruthenium nanoparticles, method for preparing, and uses thereof

    Science.gov (United States)

    Tong, YuYe; Du, Bingchen

    2015-08-11

    A superior, industrially scalable one-pot ethylene glycol-based wet chemistry method to prepare platinum-adlayered ruthenium nanoparticles has been developed that offers an exquisite control of the platinum packing density of the adlayers and effectively prevents sintering of the nanoparticles during the deposition process. The wet chemistry based method for the controlled deposition of submonolayer platinum is advantageous in terms of processing and maximizing the use of platinum and can, in principle, be scaled up straightforwardly to an industrial level. The reactivity of the Pt(31)-Ru sample was about 150% higher than that of the industrial benchmark PtRu (1:1) alloy sample but with 3.5 times less platinum loading. Using the Pt(31)-Ru nanoparticles would lower the electrode material cost compared to using the industrial benchmark alloy nanoparticles for direct methanol fuel cell applications.

  10. Silicon carbonitride, a new hard material and its relation to the confusion about 'harder than diamond' C{sub 3}N{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Badzian, A.; Badzian, T.; Roy, R.; Drawl, W. [Pennsylvania State Univ., University Park, PA (United States). Materials Research Lab.

    1999-10-08

    The claim by Cohen (1993) that powerful computational tools allow us to predict 'properties of substances even before we have created them' was made in conjunction with the claim of special properties for a hypothetical phase, C{sub 3}N{sub 4}. Among such properties was hardness, and it was asserted that, the covalent form of C{sub 3}N{sub 4} could be 'harder than diamond'. This assumption contradicted what chemists have known since 1816 in their experimentation with carbon nitrides. Never was there a single hint of the existence of a covalent, single bond C-N network. In the last decade some 400 papers have been written about this non-existent material of dubious significance (R.C. DeVries (1997)). No C{sub 3}N{sub 4} material has ever been made and the claims on both the chemical composition and crystal structure are clearly in error. The impact of such exaggerated claims on the scientific enterprise cannot be ignored. In contrast, we report herein on a related but real hard material, silicon carbonitride, with the {alpha}-Si{sub 3}N{sub 4} crystal structure modified by the introduction of carbon atoms. Synthesis of this Si-N-C crystalline material was possible by using a CH{sub 4}/H{sub 2}/N{sub 2} microwave plasma etching of solid Si. Films on Si, SiC, Si{sub 3}N{sub 4} and diamond, as well as crystal agglomerates of a few mm{sup 3} volume, have been prepared. This phase possesses a micro-hardness lower than cubic boron nitride and a band gap of 3.8 eV. The present experiments indicate that only 6 at.% of C have been incorporated into {alpha}-Si{sub 3}N{sub 4}. We might suggest that 'first principles' calculations be undertaken to explain the limited solubility of carbon in the {alpha}-Si{sub 3}N{sub 4} phase. (orig.)

  11. Morphological Study Of Border Area Of Pulp-Capping Materials And Er:YAG Laser Prepared Hard Dental Surface.

    Science.gov (United States)

    Stefanova, Vessela P; Tomov, Georgi T; Tsanova, Snezhana Ts

    2015-01-01

    Vital pulp therapy involves biologically based therapeutic activities aimed at restoring health and preserving the vitality of cariously or traumatically damaged pulp. Adaptation of pulp-capping materials to the prepared tooth surface may be the key to the success of biological tooth treatment. To investigate the area of adaptation of synthetic tricalcium silicate cement, calcium hydroxide cement and mineral trioxide-aggregate to the dentin surface, prepared with the help of Er:YAG dental laser. Four extracted human tooth cavities were prepared with the help of Er:YAG dental laser (LiteTouch, Syneron, Israel), establishing microcommunication with the pulp chamber less than 1 mm in diameter. As pulp-capping materials in the cavities we used tricalcium silicate cement (Biodentine, Septodont, France), calcium hydroxide cement (Dycal) and mineral-trioxide aggregate (ProRoot MTA), stirred and administered according to manufacturers' instructions. The first material fills the whole cavity and the other two are spread in a thin layer and sealed with glass ionomer cement. Thus prepared, the samples were left for three days at 37°C in humidified environment. The samples were prepared for scanning electron microscopy (SEM) by standard methodology. The border area surfaces of the materials and the dentin were scanned using electron microscopy. The morphological changes occurring to the Er:YAG laser prepared dentin and the structural characteristics of the studied pulp-capping materials are demonstrated using scanograms. The border areas where good contact of materials and dentinal tubules is established are thoroughly studied. Good adaptation is seen in three-calcium silicate cement, followed by mineral trioxide aggregate and calcium hydroxide cement. The dentin surface, prepared with Er:YAG laser demonstrates a very good adaptation of the three tested pulp-capping materials.

  12. Design and development of polynuclear ruthenium and platinum polypyridyl complexes in search of new anticancer agents

    NARCIS (Netherlands)

    Schilden, Karlijn van der

    2006-01-01

    The research described in this Ph.D. Thesis has been devoted to the design and development of polynuclear polypyridyl ruthenium and ruthenium-platinum complexes in search of new anticancer agents. A variety of polynuclear ruthenium and ruthenium-platinum complexes has been synthesized with a long

  13. Fischer-Tropsch synthesis process employing a moderated ruthenium catalyst

    Science.gov (United States)

    Abrevaya, Hayim

    1990-01-01

    A Fischer-Tropsch type process produces hydrocarbons from carbon monoxide and hydrogen using a novel catalyst comprising moderated ruthenium on an inorganic oxide support. The preferred moderator is silicon. Preferably the moderator is effectively positioned in relationship to ruthenium particles through simultaneous placement on the support using reverse micelle impregnation.

  14. Role of ligands in controlling the regioselectivity in ruthenium ...

    Indian Academy of Sciences (India)

    Keywords. Enol esters; DFT; regio-selectivity; ligands; ruthenium(II) catalyst. Abstract. Density functional studies are performed to understand the role of chelating bi-phosphine ligands [(Ph2P(CH2)mPPh2); m=1–4] in modulating the regio-selectivity of benzoic acid addition to 1-hexyne, in presence of ruthenium(II) catalyst ...

  15. Synthesis and structure of ruthenium(II) ternary complexes involving ...

    Indian Academy of Sciences (India)

    Administrator

    All the complexes are diamagnetic (low spin d6,. S = 0) and show intense bands corresponding to metal to ligand charge-transfer transitions and inter-ligand transitions in the UV-Vis spectra. All the complexes show one reversible oxidation due to ruthenium(II)–ruthenium(III) in the anodic region of the cyclic voltammogram.

  16. New mixed ligand complexes of ruthenium (II) that incorporate a ...

    Indian Academy of Sciences (India)

    New mixed ligand complexes of ruthenium(II) that incorporate a modified phenanthroline ligand: Synthesis, spectral characterization and DNA binding. S Murali C V ... Fulltext. Click here to view fulltext PDF ... Ruthenium(II) complexes; modified phenanthroline ligand; spectroscopy; DNA binding; fluorescence enhancement.

  17. Anticancer Activities of Mononuclear Ruthenium(II Coordination Complexes

    Directory of Open Access Journals (Sweden)

    William M. Motswainyana

    2015-01-01

    Full Text Available Ruthenium compounds are highly regarded as potential drug candidates. The compounds offer the potential of reduced toxicity and can be tolerated in vivo. The various oxidation states, different mechanism of action, and the ligand substitution kinetics of ruthenium compounds give them advantages over platinum-based complexes, thereby making them suitable for use in biological applications. Several studies have focused attention on the interaction between active ruthenium complexes and their possible biological targets. In this paper, we review several ruthenium compounds which reportedly possess promising cytotoxic profiles: from the discovery of highly active compounds imidazolium [trans-tetrachloro(dmso(imidazoleruthenate(III] (NAMI-A, indazolium [trans-tetrachlorobis(1H-indazoleruthenate(III](KP1019, and sodium trans-[tetrachloridobis(1H-indazoleruthenate(III] (NKP-1339 to the recent work based on both inorganic and organometallic ruthenium(II compounds. Half-sandwich organometallic ruthenium complexes offer the opportunity of derivatization at the arene moiety, while the three remaining coordination sites on the metal centre can be functionalised with various coordination groups of various monoligands. It is clear from the review that these mononuclear ruthenium(II compounds represent a strongly emerging field of research that will soon culminate into several ruthenium based antitumor agents.

  18. Morphological Study Of Border Area Of Pulp-Capping Materials And Er:YAG Laser Prepared Hard Dental Surface

    Directory of Open Access Journals (Sweden)

    Stefanova Vessela P.

    2015-03-01

    Full Text Available Introduction: Vital pulp therapy involves biologically based therapeutic activities aimed at restoring health and preserving the vitality of cariously or traumatically damaged pulp. Adaptation of pulp-capping materials to the prepared tooth surface may be the key to the success of biological tooth treatment.

  19. Optical Characterization of Pulse Laser Deposition of Thin Films of Hard Materials Using RHEED and AFM Techniques

    Science.gov (United States)

    2011-12-20

    MEMES in harsh environment to minimize the wear and tear. The goals of the proposed experiments are as follows: Experiment1: Study the effect of...material in magnetic recording media 1-6 . In a ferromagnetic solid, the strongly coupled atomic magnetic moments tend to be aligned

  20. Soft- to network hard-material for constructing both ion- and electron-conductive hierarchical porous structure to significantly boost energy density of a supercapacitor.

    Science.gov (United States)

    Yang, Pingping; Xie, Jiale; Guo, Chunxian; Li, Chang Ming

    2017-01-01

    Soft-material PEDOT is used to network hard Co3O4 nanowires for constructing both ion- and electron-conductive hierarchical porous structure Co3O4/PEDOT to greatly boost the capacitor energy density than sum of that of plain Co3O4 nanowires and PEDOT film. Specifically, the networked hierarchical porous structure of Co3O4/PEDOT is synthesized and tailored through hydrothermal method and post-electrochemical polymerization method for the PEDOT coating onto Co3O4 nanowires. Typically, Co3O4/PEDOT supercapacitor gets a highest areal capacitance of 160mFcm-2 at a current density of 0.2mAcm-2, which is about 2.2 times larger than the sum of that of plain Co3O4 NWs (0.92mFcm-2) and PEDOT film (69.88mFcm-2). Besides, if only PEDOT as active mass is counted, Co3O4/PEDOT cell can achieve a highest capacitance of 567.21Fg-1, this is the highest capacitance value obtained by PEDOT-based supercapacitors. Furthermore, this soft-hard network porous structure also achieves a high cycling stability of 93% capacitance retention after the 20,000th cycle. This work demonstrates a new approach to constructing both ion and electron conductive hierarchical porous structure to significantly boost energy density of a supercapacitor. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. SUPER HARD SURFACED POLYMERS

    Energy Technology Data Exchange (ETDEWEB)

    Mansur, Louis K [ORNL; Bhattacharya, R [UES, Incorporated, Dayton, OH; Blau, Peter Julian [ORNL; Clemons, Art [ORNL; Eberle, Cliff [ORNL; Evans, H B [UES, Incorporated, Dayton, OH; Janke, Christopher James [ORNL; Jolly, Brian C [ORNL; Lee, E H [Consultant, Milpitas, CA; Leonard, Keith J [ORNL; Trejo, Rosa M [ORNL; Rivard, John D [ORNL

    2010-01-01

    High energy ion beam surface treatments were applied to a selected group of polymers. Of the six materials in the present study, four were thermoplastics (polycarbonate, polyethylene, polyethylene terephthalate, and polystyrene) and two were thermosets (epoxy and polyimide). The particular epoxy evaluated in this work is one of the resins used in formulating fiber reinforced composites for military helicopter blades. Measures of mechanical properties of the near surface regions were obtained by nanoindentation hardness and pin on disk wear. Attempts were also made to measure erosion resistance by particle impact. All materials were hardness tested. Pristine materials were very soft, having values in the range of approximately 0.1 to 0.5 GPa. Ion beam treatment increased hardness by up to 50 times compared to untreated materials. For reference, all materials were hardened to values higher than those typical of stainless steels. Wear tests were carried out on three of the materials, PET, PI and epoxy. On the ion beam treated epoxy no wear could be detected, whereas the untreated material showed significant wear.

  2. CSI: Hard Drive

    Science.gov (United States)

    Sturgeon, Julie

    2008-01-01

    Acting on information from students who reported seeing a classmate looking at inappropriate material on a school computer, school officials used forensics software to plunge the depths of the PC's hard drive, searching for evidence of improper activity. Images were found in a deleted Internet Explorer cache as well as deleted file space.…

  3. Contact Allergy To Hard Contact Lens

    Directory of Open Access Journals (Sweden)

    J S Pasricha

    1985-01-01

    Full Text Available Three patients developed recurrent irritation, redness and watery discharge from their eyes after using hard contact lens. Patch tests were positive with the material of the hard contact lens and negative with teepol, sodium lauryl sulphate and material of the soft contact lens. All the three patients became alright after they stopped,using hard contact lens.

  4. Ruthenium-Aryloxide Catalysts for Olefin Metathesis

    Science.gov (United States)

    Monfette, Sebastien; Blacquiere, Johanna M.; Conrad, Jay C.; Beach, Nicholas J.; Fogg, Deryn E.

    : Advances in design of ruthenium aryloxide catalysts for olefin metathesis are described. The target complexes are accessible on reaction of RuCl2(NHC)(py)2 (CHPh) (NHC - N-heterocyclic carbene) with electron-deficient, monodentate aryl- oxides, or aryloxides that yield small, rigid chelate rings. The best of these catalysts offer activity comparable to or greater than that of the parent chloride (Grubbs) systems in ring-closing metathesis (RCM). Preliminary studies of the electronic nature of the Ru-X bond suggest that the metal center is more electropositive in the aryloxide complexes than in the Grubbs systems.

  5. Structure and reactivity of Ruthenium nanoparticles

    DEFF Research Database (Denmark)

    Gavnholt, Jeppe; Schiøtz, Jakob

    2008-01-01

    We present a method for obtaining detailed structural information of ruthenium nanoparticles in at least the diameter range from 1.5 to 5 nm. The method is based on an ensemble approach where a large number of low-energy structures are collected in an ensemble, from which average properties can......; the presence of step sites is mainly a function of the lowest energy shape of the cluster, i.e., a function of the number of atoms. By combining the structural information with estimations of the single site activities in the ammonia synthesis, we find that the optimal particle diameter is approximately 3 nm...

  6. Development of a Method for the Preparation of Ruthenium Indenylidene-Ether Olefin Metathesis Catalysts

    Directory of Open Access Journals (Sweden)

    Yann Schrodi

    2012-05-01

    Full Text Available The reactions between several derivatives of 1-(3,5-dimethoxyphenyl-prop-2-yn-1-ol and different ruthenium starting materials [i.e., RuCl2(PPh33 and RuCl2(p-cymene(L, where L is tricyclohexylphosphine di-t-butylmethylphosphine, dicyclohexylphenylphosphine, triisobutylphosphine, triisopropylphosphine, or tri-n-propylphosphine] are described. Several of these reactions allow for the easy, in-situ and atom-economic preparation of olefin metathesis catalysts. Organic precursor 1-(3,5-dimethoxyphenyl-1-phenyl-prop-2-yn-1-ol led to the formation of active ruthenium indenylidene-ether complexes, while 1-(3,5-dimethoxyphenyl-prop-2-yn-1-ol and 1-(3,5-dimethoxyphenyl-1-methyl-prop-2-yn-1-ol did not. It was also found that a bulky and strong σ-donor phosphine ligand was required to impart good catalytic activity to the new ruthenium complexes.

  7. Hard superconducting nitrides

    Science.gov (United States)

    Chen, Xiao-Jia; Struzhkin, Viktor V.; Wu, Zhigang; Somayazulu, Maddury; Qian, Jiang; Kung, Simon; Christensen, Axel Nørlund; Zhao, Yusheng; Cohen, Ronald E.; Mao, Ho-kwang; Hemley, Russell J.

    2005-01-01

    Detailed study of the equation of state, elasticity, and hardness of selected superconducting transition-metal nitrides reveals interesting correlations among their physical properties. Both the bulk modulus and Vickers hardness are found to decrease with increasing zero-pressure volume in NbN, HfN, and ZrN. The computed elastic constants from first principles satisfy c11 > c12 > c44 for NbN, but c11 > c44 > c12 for HfN and ZrN, which are in good agreement with the neutron scattering data. The cubic δ-NbN superconducting phase possesses a bulk modulus of 348 GPa, comparable to that of cubic boron nitride, and a Vickers hardness of 20 GPa, which is close to sapphire. Theoretical calculations for NbN show that all elastic moduli increase monotonically with increasing pressure. These results suggest technological applications of such materials in extreme environments. PMID:15728352

  8. Ruthenium Dioxide Catalysts for the Selective Oxidation of Benzylamine to Benzonitrile: Investigating the Effect of Ruthenium Loading on Physical and Catalytic Properties

    DEFF Research Database (Denmark)

    Nordvang, Emily Catherine; Schill, Leonhard; Riisager, Anders

    2017-01-01

    The oxidative dehydrogenation of benzylamine to benzonitrile was studied in batch and continuous flow processes using ruthenium dioxide catalysts with varying ruthenium loadings. Increased conversions were observed in the continuous flow process compared with the batch process (up to 100% in the ......The oxidative dehydrogenation of benzylamine to benzonitrile was studied in batch and continuous flow processes using ruthenium dioxide catalysts with varying ruthenium loadings. Increased conversions were observed in the continuous flow process compared with the batch process (up to 100...

  9. Studying the effect of Ruthenium on High Temperature Mechanical Properties of Nickel Based Superalloys and Determining the Universal Behavior of Ruthenium at Atomic Scale with respect to alloying elements, Stress and Temperature

    Directory of Open Access Journals (Sweden)

    Sriswaroop Dasari

    2016-10-01

    Full Text Available Any property of a material is a function of its microstructure and microstructure is a function of material composition. So, to maximize the desired properties of a material, one has to understand the evolution of microstructure which in turn is nothing but the reflection of the role of alloying elements. Research has not been done to understand the universal behavior of a certain base/alloying element. Let’s take the example of Cl- ion in HCl, we all know that in general, chloride ion can only be replaced by Fluoride or oxygen ion and that no other ion can replace it. But when you consider a metal like Ni, Co, Cr, Fe etc. there is no establishment that it behaves only in a certain way. Though I concord to the fact that discovery of universal behavior of Ni is lot complex than chloride ion, I think that future research should be focused in this direction also. Superalloys are the candidate materials required to improve thermal efficiency of a gas turbine by allowing higher turbine inlet gas temperatures. Gas turbines are the heart of local power systems, next generation jet engines and high performance space rockets. Recent research in superalloys showed that addition of some alloying elements in minor quantities can result in drastic change in properties. Such an alloying element is Ruthenium (Ru. Addition of Ruthenium to superalloys has shown improvement in mechanical properties by an order of magnitude. However reasons for such improvement are not known yet. Hence, there is a need to identify its role and discover the universal behavior of ruthenium to utilize it efficiently. In this proposal, we study materials with different compositions that are derived based on one ruthenium containing superalloy, and different thermomechanical history. Based on the evolution of microstructures and results of mechanical testing, we plan to determine the exact role of Ruthenium and prediction of its behavior with respect to other elements in the material

  10. Standard hardness conversion tables for metals relationship among brinell hardness, vickers hardness, rockwell hardness, superficial hardness, knoop hardness, and scleroscope hardness

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 Conversion Table 1 presents data in the Rockwell C hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.2 Conversion Table 2 presents data in the Rockwell B hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.3 Conversion Table 3 presents data on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, and Knoop hardness of nickel and high-nickel alloys (nickel content o...

  11. Preliminary design of a zone plate based hard X-ray monochromatic diffraction nanoprobe for materials studies at APS

    Science.gov (United States)

    Cai, Zhonghou; Liu, Wenjun; Tischler, Jonathan Z.; Shu, Deming; Xu, Ruqing; Schmidt, Oliver

    2013-09-01

    Aiming at studies of the micro/nano-structures of a broad range materials and electronic devices, Advance Photon Source (APS) is developing a dedicated diffraction nanoprobe (DNP) beamline for the needs arising from a multidiscipline research community. As a part of the APS Upgrade Project, the planed facility, named Sub-micron 3-D Diffraction (S3DD) beamline1, integrates the K-B mirror based polychromatic Laue diffraction and the Fresnel zone-plate based monochromatic diffraction techniques that currently support 3D/2D microdiffraction programs at the 34-ID-E and 2-ID-D of the APS, respectively. Both diffraction nanoprobes are designed to have a 50-nm or better special resolution. The zone-plate based monochromatic DNP has been preliminarily designed and will be constructed at the sector 34-ID. It uses an APS-3.0-cm period or APS-3.3-cm period undulator, a liquid-nitrogen cooled mirror as its first optics, and a water cooled small gap silicon double-crystal monochromator with an energy range of 5-30 keV. A set of zone plates have been designed to optimize for focusing efficiency and the working distance based on the attainable beamline length and the beam coherence. To ensure the nanoprobe performance, high stiffness and high precision flexure stage systems have been designed or demonstrated for optics mounting and sample scanning, and high precision temperature control of the experimental station will be implemented to reduce thermal instability. Designed nanoprobe beamline has a good management on thermal power loading on optical components and allows high degree of the preservation of beam brilliance for high focal flux and coherence. Integrated with variety of X-ray techniques, planed facility provides nano-XRD capability with the maximum reciprocal space accessibility and allows micro/nano-spectroscopy studies with K-edge electron binding energies of most elements down to Vanadium in the periodic table. We will discuss the preliminary design of the zone

  12. Building Indenylidene-Ruthenium Catalysts for Metathesis Transformations

    Science.gov (United States)

    Clavier, Hervé; Nolan, Steven P.

    Ruthenium-mediated olefin metathesis has emerged as an indispensable tool in organic synthesis for the formation carbon-carbon double bonds, attested by the large number of applications for natural product synthesis. Among the numerous catalysts developed to mediate olefin metathesis transformations, ruthenium-indenylidene complexes are robust and powerful pre-catalysts. The discovery of this catalyst category was slightly muddled due to a first mis-assignment of the compound structure. This report provides an overview of the synthetic routes for the construction of the indenylidene pattern in ruthenium complexes. The parameters relating to the indenylidene moiety construction will be discussed as well as the mechanism of this formation

  13. Ultrashort pulsed laser (USPL) application in dentistry: basic investigations of ablation rates and thresholds on oral hard tissue and restorative materials.

    Science.gov (United States)

    Schelle, Florian; Polz, Sebastian; Haloui, Hatim; Braun, Andreas; Dehn, Claudia; Frentzen, Matthias; Meister, Jörg

    2014-11-01

    Modern ultrashort pulse lasers with scanning systems provide a huge set of parameters affecting the suitability for dental applications. The present study investigates thresholds and ablation rates of oral hard tissues and restorative materials with a view towards a clinical application system. The functional system consists of a 10 W Nd:YVO4 laser emitting pulses with a duration of 8 ps at 1,064 nm. Measurements were performed on dentin, enamel, ceramic, composite, and mammoth ivory at a repetition rate of 500 kHz. By employing a scanning system, square-shaped cavities with an edge length of 1 mm were created. Ablation threshold and rate measurements were assessed by variation of the applied fluence. Examinations were carried out employing a scanning electron microscope and optical profilometer. Irradiation time was recorded by the scanner software in order to calculate the overall ablated volume per time. First high power ablation rate measurements were performed employing a laser source with up to 50 W. Threshold values in the range of 0.45 J/cm(2) (composite) to 1.54 J/cm(2) (enamel) were observed. Differences between any two materials are statistically significant (p laser source and differed statistically significant for any two materials (p  0.05). By employing the 50 W laser source, increased rates up to ∼50 mm(3)/min for dentin were obtained. The results indicate that modern USPL systems provide sufficient ablation rates to be seen as a promising technology for dental applications.

  14. Soft versus hard nanoparticles in the delivery of aromatic ...

    African Journals Online (AJOL)

    McRoy

    coated hard nanoparticles). E) Nanoparticles with compact core covered by a porous material with the photosensitisers covalently bonded (hybrid nanoparticles and silica-coated hard nanoparticles). The first attempt to target hard nanoparticles.

  15. Half-sandwich ruthenium, rhodium and iridium complexes of ...

    Indian Academy of Sciences (India)

    sandwich ruthenium, rhodium and iridium complexes of triazolopyridine ligand: Synthesis and structural studies. NARASINGA RAO PALEPU RAO MOHAN KOLLIPARA. Regular Article Volume 129 Issue 2 February 2017 pp 177-184 ...

  16. Tuning oxygen sensitivity of ruthenium complex exploiting silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ozturk, Osman [Department of Chemistry, Faculty of Science, University of Dicle, Diyarbakır (Turkey); Oter, Ozlem [Department of Chemistry, Faculty of Science, University of Dokuz Eylul, 35397 Buca, Izmir (Turkey); Center for Fabrication and Application of Electronic Materials (EMUM), University of Dokuz Eylul, 35397 Buca, Tinaztepe, Izmir (Turkey); Department of Nanoscience and Nanoengineering, University of Dokuz Eylul, 35397 Buca, Tinaztepe, Izmir (Turkey); Yildirim, Serdar [Center for Fabrication and Application of Electronic Materials (EMUM), University of Dokuz Eylul, 35397 Buca, Tinaztepe, Izmir (Turkey); Department of Metallurgical and Materials Engineering, University of Dokuz Eylul, 35397 Buca, Tinaztepe, Izmir (Turkey); Subasi, Elif [Department of Chemistry, Faculty of Science, University of Dokuz Eylul, 35397 Buca, Izmir (Turkey); Department of Nanoscience and Nanoengineering, University of Dokuz Eylul, 35397 Buca, Tinaztepe, Izmir (Turkey); Ertekin, Kadriye, E-mail: kadriye.ertekin@deu.edu.tr [Department of Chemistry, Faculty of Science, University of Dokuz Eylul, 35397 Buca, Izmir (Turkey); Center for Fabrication and Application of Electronic Materials (EMUM), University of Dokuz Eylul, 35397 Buca, Tinaztepe, Izmir (Turkey); Department of Nanoscience and Nanoengineering, University of Dokuz Eylul, 35397 Buca, Tinaztepe, Izmir (Turkey); Celik, Erdal [Center for Fabrication and Application of Electronic Materials (EMUM), University of Dokuz Eylul, 35397 Buca, Tinaztepe, Izmir (Turkey); Department of Nanoscience and Nanoengineering, University of Dokuz Eylul, 35397 Buca, Tinaztepe, Izmir (Turkey); Department of Metallurgical and Materials Engineering, University of Dokuz Eylul, 35397 Buca, Tinaztepe, Izmir (Turkey); Temel, Hamdi [Department of Chemistry, Faculty of Science, University of Dicle, Diyarbakır (Turkey)

    2014-11-15

    In this study, we utilized silver nanoparticles (Ag NPs) along with ionic liquids as additives for fabrication of polymeric oxygen sensitive fibers. Plasticized polymethyl methacrylate and ethyl cellulose (EC) were used as matrix materials. Fibers and porous films were produced by electrospinning technique. Oxygen induced spectral response of the fluorescent tris(2,2′-bipyridyl) ruthenium(II) chloride (Ru(bipy){sub 3}{sup 2+}) was followed as the analytical signal. Utilization of silver nanoparticles in electrospun polymeric fibers for oxygen sensing purposes resulted with many advantages such as tuned sensitivity, linear calibration plot for larger concentration ranges, increased surface area and enhancement in all sensor dynamics. Linearity of the calibration plot for the offered composition was superior with respect to the previously reported ones. When stored at the ambient air of the laboratory there was no significant drift in intensity after 12 months. Our sensitivity and stability tests are still in progress. - Highlights: • Ag nanoparticles and Ru(II) complex doped together into polymers for the first time for O{sub 2} sensing. • The ionic liquid EMIMBF{sub 4} was used for matrix modification. • Fabricated electrospun nanofibers offered enhanced linearity for a large concentration range. • Exploited polymeric matrix materials and additives provided long-term stability. • Silver nanoparticles tuned oxygen sensitivity and facilitated fabrication process.

  17. Prediction of Stable Ruthenium Silicides from First-Principles Calculations: Stoichiometries, Crystal Structures, and Physical Properties.

    Science.gov (United States)

    Zhang, Chuanzhao; Kuang, Xiaoyu; Jin, Yuanyuan; Lu, Cheng; Zhou, Dawei; Li, Peifang; Bao, Gang; Hermann, Andreas

    2015-12-09

    We present results of an unbiased structure search for stable ruthenium silicide compounds with various stoichiometries, using a recently developed technique that combines particle swarm optimization algorithms with first-principles calculations. Two experimentally observed structures of ruthenium silicides, RuSi (space group P2(1)3) and Ru2Si3 (space group Pbcn), are successfully reproduced under ambient pressure conditions. In addition, a stable RuSi2 compound with β-FeSi2 structure type (space group Cmca) was found. The calculations of the formation enthalpy, elastic constants, and phonon dispersions demonstrate the Cmca-RuSi2 compound is energetically, mechanically, and dynamically stable. The analysis of electronic band structures and densities of state reveals that the Cmca-RuSi2 phase is a semiconductor with a direct band gap of 0.480 eV and is stabilized by strong covalent bonding between Ru and neighboring Si atoms. On the basis of the Mulliken overlap population analysis, the Vickers hardness of the Cmca structure RuSi2 is estimated to be 28.0 GPa, indicating its ultra-incompressible nature.

  18. Rare earth-ruthenium-magnesium intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Sebastian; Kersting, Marcel; Heletta, Lukas; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2017-07-01

    Eight new intermetallic rare earth-ruthenium-magnesium compounds have been synthesized from the elements in sealed niobium ampoules using different annealing sequences in muffle furnaces. The compounds have been characterized by powder and single crystal X-ray diffraction. Sm{sub 9.2}Ru{sub 6}Mg{sub 17.8} (a=939.6(2), c=1779(1) pm), Gd{sub 11}Ru{sub 6}Mg{sub 16} (a=951.9(2), c=1756.8(8) pm), and Tb{sub 10.5}Ru{sub 6}Mg{sub 16.5} (a=942.5(1), c=1758.3(4) pm) crystallize with the tetragonal Nd{sub 9.34}Ru{sub 6}Mg{sub 17.66} type structure, space group I4/mmm. This structure exhibits a complex condensation pattern of square-prisms and square-antiprisms around the magnesium and ruthenium atoms, respectively. Y{sub 2}RuMg{sub 2} (a=344.0(1), c=2019(1) pm) and Tb{sub 2}RuMg{sub 2} (a=341.43(6), c=2054.2(7) pm) adopt the Er{sub 2}RuMg{sub 2} structure and Tm{sub 3}Ru{sub 2}Mg (a=337.72(9), c=1129.8(4) pm) is isotypic with Sc{sub 3}Ru{sub 2}Mg. Tm{sub 3}Ru{sub 2}Mg{sub 2} (a=337.35(9), c=2671(1) pm) and Lu{sub 3}Ru{sub 2}Mg{sub 2} (a=335.83(5), c=2652.2(5) pm) are the first ternary ordered variants of the Ti{sub 3}Cu{sub 4} type, space group I4/mmm. These five compounds belong to a large family of intermetallics which are completely ordered superstructures of the bcc subcell. The group-subgroup scheme for Lu{sub 3}Ru{sub 2}Mg{sub 2} is presented. The common structural motif of all three structure types are ruthenium-centered rare earth cubes reminicent of the CsCl type. Magnetic susceptibility measurements of Y{sub 2}RuMg{sub 2} and Lu{sub 3}Ru{sub 2}Mg{sub 2} samples revealed Pauli paramagnetism of the conduction electrons.

  19. Systematic hardness studies on lithium niobate crystals

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 23; Issue 2. Systematic hardness studies on lithium niobate crystals ... In view of discrepancies in the available information on the hardness of lithium niobate, a systematic study of the hardness has been carried out. Measurements have been made on two pure lithium ...

  20. Structural evolution of small ruthenium cluster anions

    Energy Technology Data Exchange (ETDEWEB)

    Waldt, Eugen [Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, 76021 Karlsruhe (Germany); Hehn, Anna-Sophia; Ahlrichs, Reinhart [Institute für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76128 Karlsruhe (Germany); Kappes, Manfred M.; Schooss, Detlef, E-mail: detlef.schooss@kit.edu [Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, 76021 Karlsruhe (Germany); Institute für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76128 Karlsruhe (Germany)

    2015-01-14

    The structures of ruthenium cluster anions have been investigated using a combination of trapped ion electron diffraction and density functional theory computations in the size range from eight to twenty atoms. In this size range, three different structural motifs are found: Ru{sub 8}{sup −}–Ru{sub 12}{sup −} have simple cubic structures, Ru{sub 13}{sup −}–Ru{sub 16}{sup −} form double layered hexagonal structures, and larger clusters form close packed motifs. For Ru{sub 17}{sup −}, we find hexagonal close packed stacking, whereas octahedral structures occur for Ru{sub 18}{sup −}–Ru{sub 20}{sup −}. Our calculations also predict simple cubic structures for the smaller clusters Ru{sub 4}{sup −}–Ru{sub 7}{sup −}, which were not accessible to electron diffraction measurements.

  1. The analysis of effect of heat treatment temperature on micro structure, crystal structure and hardness material on alloy Zr 96,2 Sn 2,3Nb1.1 Fe0,4

    Science.gov (United States)

    Saing, Bungaran; Budiarto

    2017-09-01

    The effect of heat treatment temperature (in 500 0C, 600 0C, and 700 0C) from Zr 96,2 Sn 2,3Nb1.1 Fe0,4 as fuel cladding material candidate’s reactor nuclear power plant; for microstructure, crystal structure, and hardness has been carried out. Several characteristic was conducted by using an optical microscope, x-ray diffractometer and Vickers method. The result showed the crystalline characteristic peaks by a tendency to a single crystal formation and microstructure is getting better with less precipitation and the hardness of the alloy is 329.6 4.5 HVN after the homogenization process.

  2. Efficient Removal of Ruthenium Byproducts from Olefin Metathesis Products by Simple Aqueous Extraction

    Science.gov (United States)

    Hong, Soon Hyeok; Grubbs, Robert H.

    2008-01-01

    Simple aqueous extraction removed ruthenium byproducts efficiently from ring-closing metathesis (RCM) reactions catalyzed by a PEG-supported N-heterocyclic carbene-based ruthenium complex. PMID:17428062

  3. Ruthenium-Vinylidene Complexes: An Efficient Class of Homogeneous Metathesis Catalysts

    Science.gov (United States)

    Dragutan, Ileana; Verpoort, Francis; Dragutan, Valerian; Drozdzak, Renata

    Several routes to access ruthenium (Ru)-vinylidene complexes are described, the majority of which employ alkynes and a Ru source as the starting materials. The successful application of Ru-vinylidenes as efficient pre-catalysts for the synthesis of carbocyclic and heterocyclic compounds by ring-closing metathesis (RCM) of αω, -dienes, and in the synthesis of polymers by ring-opening metathesis polymerization (ROMP) of cyclooctene, norbornene, 5-substituted norbornene, and dicyclopentadiene is fully illustrated. Relevant aspects concerning the activity and selectivity of this type of Ru complexes in metathesis reactions are highlighted.

  4. Acetic Acid Formation by Selective Aerobic Oxidation of Aqueous Ethanol over Heterogeneous Ruthenium Catalysts

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Hanning, Christopher William

    2012-01-01

    Heterogeneous catalyst systems comprising ruthenium hydroxide supported on different carrier materials, titania, alumina, ceria, and spinel (MgAl2O4), were applied in selective aerobic oxidation ethanol to form acetic acid, an important bulk chemical and food ingredient. The catalysts were...... of catalysts, oxidant pressure, reaction temperature, and substrate concentration were investigated. Quantitative yield of acetic acid was obtained with 1.2 wt % Ru(OH)x/CeO2 under optimized conditions (150 °C, 10 bar O2, 12 h of reaction time, 0.23 mol % Ru to substrate)....

  5. Titanium and Ruthenium Phthalocyanines for NO2 Sensors: A Mini-Review

    Directory of Open Access Journals (Sweden)

    Valerio Rossi Albertini

    2009-07-01

    Full Text Available This review presents studies devoted to the description and comprehension of phenomena connected with the sensing behaviour towards NO2 of films of two phthalocyanines, titanium bis-phthalocyanine and ruthenium phthalocyanine. Spectroscopic, conductometric, and morphological features recorded during exposure to the gas are explained and the mechanisms of gas-molecule interaction are also elucidated. The review also shows how X-ray reflectivity can be a useful tool for monitoring morphological parameters such as thickness and roughness that are demonstrated to be sensitive variables for monitoring the exposure of thin films of sensor materials to NO2 gas.

  6. Ruthenium Sensitizers and Their Applications in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Yuancheng Qin

    2012-01-01

    Full Text Available Dye-sensitized solar cells (DSSCs have attracted considerable attention in recent years due to the possibility of low-cost conversion of photovoltaic energy. The DSSCs-based ruthenium complexes as sensitizers show high efficiency and excellent stability, implying potential practical applications. This review focuses on recent advances in design and preparation of efficient ruthenium sensitizers and their applications in DSSCs, including thiocyanate ruthenium sensitizers and thiocyanate-free ruthenium sensitizers.

  7. Kinetics and Photochemistry of Ruthenium Bisbipyridine Diacetonitrile Complexes: An Interdisciplinary Inorganic and Physical Chemistry Laboratory Exercise

    Science.gov (United States)

    Rapp, Teresa L.; Phillips, Susan R.; Dmochowski, Ivan J.

    2016-01-01

    The study of ruthenium polypyridyl complexes can be widely applied across disciplines in the undergraduate curriculum. Ruthenium photochemistry has advanced many fields including dye-sensitized solar cells, photoredox catalysis, lightdriven water oxidation, and biological electron transfer. Equally promising are ruthenium polypyridyl complexes…

  8. Hardly Hardware

    Science.gov (United States)

    Lott, Debra

    2007-01-01

    In a never-ending search for new and inspirational still-life objects, the author discovered that home improvement retailers make great resources for art teachers. Hardware and building materials are inexpensive and have interesting and variable shapes. She especially liked the dryer-vent coils and the electrical conduit. These items can be…

  9. Ruthenium(II)-catalysed remote C-H alkylations as a versatile platform to meta-decorated arenes

    Science.gov (United States)

    Li, Jie; Korvorapun, Korkit; de Sarkar, Suman; Rogge, Torben; Burns, David J.; Warratz, Svenja; Ackermann, Lutz

    2017-06-01

    The full control of positional selectivity is of prime importance in C-H activation technology. Chelation assistance served as the stimulus for the development of a plethora of ortho-selective arene functionalizations. In sharp contrast, meta-selective C-H functionalizations continue to be scarce, with all ruthenium-catalysed transformations currently requiring difficult to remove or modify nitrogen-containing heterocycles. Herein, we describe a unifying concept to access a wealth of meta-decorated arenes by a unique arene ligand effect in proximity-induced ruthenium(II) C-H activation catalysis. The transformative nature of our strategy is mirrored by providing a step-economical entry to a range of meta-substituted arenes, including ketones, acids, amines and phenols--key structural motifs in crop protection, material sciences, medicinal chemistry and pharmaceutical industries.

  10. Enhanced photovoltaic effect of ruthenium complex-modified graphene oxide with P-type conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei, E-mail: jj_zw_js@sina.com.cn; Bai, Huicong; Zhang, Yu; Sun, Ying; Lin, Shen; Liu, Jian; Yang, Qi; Song, Xi-Ming, E-mail: songlab@lnu.edu.cn

    2014-10-15

    A graphene oxide nanocomposite with bis(1,10-phenanthroline)(N-(2-aminoethyl)-4-(4-methyl-2,2-bipyridine-4-yl) formamide) ruthenium (Ru(phen){sub 2}(bpy-NH{sub 2})(PF{sub 6}){sub 2}), a ruthenium complex, was synthesized by amidation reaction between amino group of the ruthenium complex and carboxyl group of GO. The as-prepared Ru(II)–GO composite was characterized by infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) absorption spectra, fluorescence spectra, surface photovoltage (SPV) spectrum and transient photovoltage (TPV) technology. This nanocomposite showed a typical p-type character and an enhanced photovoltaic effect at long timescale of about 3 × 10{sup −3} s compared to GO alone. A reversible rise/decay of the photocurrent in response to the on/off illumination step was also observed in a photoelectrochemical cell of the Ru(II)–GO composite. The photocurrent response of the Ru(II)–GO film was remarkably higher than that of GO film. Therefore, this Ru(II)–GO composite is believed to be a promising p-type photoelectric conversion material for further photovoltaic applications. - Highlights: • A new dye-sensitized graphene oxide nanocomposite was reported. • A photo-induced charge transfer process in this nanocomposite was confirmed. • This composite showed a typical p-type conductivity. • This composite showed an enhanced photovoltaic effect at a long timescale.

  11. Nitrofurylsemicarbazone rhenium and ruthenium complexes as anti-trypanosomal agents.

    Science.gov (United States)

    Otero, Lucía; Aguirre, Gabriela; Boiani, Lucía; Denicola, Ana; Rigol, Carolina; Olea-Azar, Claudio; Maya, Juan Diego; Morello, Antonio; González, Mercedes; Gambino, Dinorah; Cerecetto, Hugo

    2006-11-01

    Rhenium and ruthenium complexes of the type [Re(V)OCl(2)(PPh(3))L] and [Ru(II)Cl(2)(DMSO)(2)L], where L are 5-nitrofurylsemicarbazone derivatives, were prepared in an effort to obtain new anti-trypanosomal agents combining the recognized biological activity of these metals and the trypanocidal activity of the free ligands. Rhenium complexes resulted unstable in aqueous solution not allowing their use as potential drugs. On the other hand, complexation to ruthenium of the bioactive ligands lead to the lack of antiprotozoa activity even though free radical production and redox cycling induction were detected when the compounds were incubated in presence of Trypanosoma cruzi cells. The lack of anti-trypanosomal activity of ruthenium complexes could be explained on the basis of their high protein binding capacity and their high hydrophilicity.

  12. Hydrothermal synthesis and physicochemical properties of ruthenium(0) nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Dikhtiarenko, A., E-mail: dikhtiarenkoalla@uniovi.es [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Khainakov, S.A.; Garcia, J.R.; Gimeno, J. [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Pedro, I. de; Fernandez, J. Rodriguez [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Blanco, J.A. [Departamento de Fisica, Universidad de Oviedo, 33007 Oviedo (Spain)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Ruthenium nanoparticles were synthesized by hydrothermal technique. Black-Right-Pointing-Pointer The average size of the nanoparticles are depend on the reducing agent used. Black-Right-Pointing-Pointer The magnetic response seems to be dominated by a paramagnetic contribution characteristic of the band electronic magnetism of the ruthenium(0) nanoparticles. - Abstract: The synthesis of ruthenium nanoparticles in hydrothermal conditions using mild reducing agents (succinic acid, ascorbic acid and sodium citrate) is reported. The shape of the nanoparticles depends on the type of the reducing agent, while the size is more influenced by the pH of the medium. The magnetic response seems to be dominated by a paramagnetic contribution characteristic of the band electronic magnetism of the nanoparticles.

  13. Application of the chemical properties of ruthenium to decontamination processes; L'application des proprietes chimiques du ruthenium a des procedes de decontamination

    Energy Technology Data Exchange (ETDEWEB)

    Fontaine, A.; Berger, D. [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

    1965-07-01

    The chemical properties of ruthenium in the form of an aqueous solution of the nitrate and of organic tributylphosphate solution are reviewed. From this data, some known examples are given: they demonstrate the processes of separation or of elimination of ruthenium from radioactive waste. (authors) [French] Les proprietes chimiques du ruthenium en solutions aqueuses nitriques et en solutions organiques de tributylphosphate, sont passees en revue. A partir de ces donnees, quelques exemples connus sont cites: ils exposent des procedes de separation ou d'elimination du ruthenium de dechets radioactifs. (auteurs)

  14. Long term test of buffer material at the Aespoe Hard Rock Laboratory, LOT project. Final report on the A2 test parcel

    Energy Technology Data Exchange (ETDEWEB)

    Karnland, Ola; Olsson, Siv; Dueck, Ann; Birgersson, Martin; Nilsson, Ulf; Hernan-Haakansson, Tania (Clay Technology AB, Lund (Sweden)); Pedersen, Karsten (Microbial Analytics Sweden AB (Sweden); Goeteborg Univ., Dept. of Cell and Molecular Biology, Goeteborg (Sweden)); Nilsson, Sara; Eriksen, Trygve E. (School of Chemical Science and Engineering, Nuclear chemistry, Royal Inst. of Tech., Stockholm (Sweden)); Rosborg, Bo (Rosborg Consulting, Nykoeping (Sweden))

    2009-11-15

    In the Swedish repository concept for nuclear waste (KBS-3 concept), the spent nuclear fuel will be stored in copper canisters surrounded by compacted bentonite. The decaying power of the fuel will increase the temperature in the repository which, in combination with the uptake of ground-water, are expected to result in minor mineralogical changes in the bentonite. The ongoing LOT test series at the Aespoe Hard Rock Laboratory (HRL) are focused on identifying and quantifying such mineralogical alterations in the bentonite exposed to typical repository-like conditions. Further, buffer-related processes concerning copper corrosion, cation transport, and bacterial survival/activity are studied. In total, the LOT project includes seven test parcels, which contain a central Cu-tube surrounded by cylindrical bentonite blocks with a diameter of 30 cm, and gauges for temperature, total pressure, water pressure and humidity. Electrical heaters placed inside the copper tube are used to simulate the power from the decaying spent fuel. Three parcels are exposed to standard KBS-3 conditions (maximum temperature below 100 deg C) and four parcels to adverse conditions (maximum temperature below approx140 deg C). Both the standard and the adverse test series include short term tests (1 to 2 years), medium term tests (>5 years) and long term tests (>10 years). The present report concerns the A2 test parcel, which was a medium term test exposed to adverse conditions. Cu-coupons, 60Co tracers, bacteria and specific chemical substances were placed in the bentonite at defined positions. After field exposure, the entire test parcel was released from the rock by overlapping percussion drilling and wire sawing. The parcel was lifted and divided at test site and the bentonite material was sampled for specified analyses performed by nine different laboratories in five countries. The main aspects of the various tests and analyses may be summarized in the following items: - physical

  15. Ruthenium nanoparticles for oxygen reduction and/or hydrogen oxidation, prepared by pyrolysis in a reducing atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Altamirano-Gutierrez, A.; Villagran-Naredo, J.L.A.; Jimenez-Sandoval, O. [Inst. Politecnico Nacional (Mexico). Centro de Investigacion y de Estudios Avanzados; Hernandez-Castellanos, R. [Centro de Investigacion y Desarrollo Technologic en Electroquimica (Mexico)

    2006-07-01

    An investigation of the synthesis, structural and electrochemical characterization of ruthenium-based materials prepared by pyrolysis was presented. Ru{sub 3}(CO){sub 12} materials were pyrolized in a hydrogen atmosphere at 80, 140, 360 and 460 degrees C. The materials were then characterized using Fourier Transform Infrared (FTIR) spectroscopy; X-ray diffraction (XRD) and scanning electron microscopy (SEM). Oxygen reduction reactions (ORR) and hydrogen oxidation reactions (HOR) were evaluated through the use of rotating disk electrode measurements in a 0.5 M hydrogen peroxide (H{sub 2}SO{sub 4}) electrolyte at room temperature. Results of the investigation indicated that the Ru{sub 3}(CO){sub 12} precursor was completely decarbonylated in H{sub 2} at 140 degrees C. Carbonyl group bands were observed when the materials were prepared at 80 degrees C due to the formation of an inactive Ru cluster resulting from a structural rearrangement of the cluster. Polarization curves indicated that the materials prepared at 140 degrees C were able to perform the ORR and HOR in an acid medium similar to the medium present in proton exchange (PE) fuel cells. The electrokinetic parameters indicated that the exchange current densities were of the same order as platinum (Pt) current densities, and that the ORR occurred via 4 electrons due to the direct formation of water. Tafel slope values for the HOR suggested that the mechanism of the reaction was related to Herovsky/Volmer types. It was concluded that the use of a reductive atmosphere in the preparation process of ruthenium-based materials prevents the formation of undesirable ruthenium oxides. The nano-sized materials prepared during the experiment did not exhibit loss of their catalytic properties after being exposed to air for several weeks. 4 refs., 2 figs.

  16. {sup 106}Ruthenium Plaque Therapy (RPT) for Retinoblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Naoya, E-mail: namuraka@ncc.go.jp [Department of Radiation Oncology, National Cancer Center Hospital, Tokyo (Japan); Suzuki, Shigenobu [Department of Ophthalmic Oncology, National Cancer Center Hospital, Tokyo (Japan); Ito, Yoshinori [Department of Radiation Oncology, National Cancer Center Hospital, Tokyo (Japan); Yoshimura, Ryoichi [Department of Diagnostic Radiology and Oncology, Head and Neck Reconstruction Division, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Inaba, Koji; Kuroda, Yuki; Morota, Madoka; Mayahara, Hiroshi; Sakudo, Mototake; Wakita, Akihisa; Okamoto, Hiroyuki; Sumi, Minako; Kagami, Yoshikazu [Department of Radiation Oncology, National Cancer Center Hospital, Tokyo (Japan); Nakagawa, Keiichi; Ohtomo, Kuni [Department of Radiology, University of Tokyo Hospital, Tokyo (Japan); Itami, Jun [Department of Radiation Oncology, National Cancer Center Hospital, Tokyo (Japan)

    2012-09-01

    Purpose: To evaluate the effectiveness of episcleral {sup 106}ruthenium plaque therapy (RPT) in the management of retinoblastoma. Methods and Materials: One hundred one RPTs were retrospectively analyzed that were performed in 90 eyes of 85 patients with retinoblastoma at National Cancer Center Hospital between 1998 and 2008. Each RPT had a corresponding tumor and 101 tumors were considered in the analysis of local control. Median follow-up length was 72.8 months. Median patient age at the RPT was 28 months. Median prescribed doses at reference depth and outer surface of the sclera were 47.4 Gy and 162.3 Gy, respectively. Results: Local control rate (LCR) and ocular retention rate (ORR) at 2 years were 33.7% and 58.7%, respectively. Unilateral disease, International Classification of Retinoblastoma group C or more advanced at the first presentation or at the time of RPT, vitreous and/or subretinal seeding, tumor size greater than 5 disc diameter (DD), reference depth greater than 5 mm, dose rate at reference depth lower than 0.7 Gy/hour, dose at the reference depth lower than 35 Gy, and (biologically effective dose with an {alpha}/{beta} ratio of 10 Gy) at the reference depth lower than 40 Gy{sub 10} were associated with unfavorable LCR. Two patients died of metastatic disease. Radiation complications included retinal detachment in 12 eyes (13.3%), proliferative retinopathy in 6 (6.7%), rubeosis iris in 2 (2.2%), and posterior subcapsular cataract in 23 (25.6%). Conclusion: RPT is an effective eye-preserving treatment for retinoblastoma.

  17. Nanoengineering of Ruthenium and Platinum-based Nanocatalysts by Continuous-Flow Chemistry for Renewable Energy Applications

    KAUST Repository

    AlYami, Noktan Mohammed

    2017-04-15

    This thesis presents an integrated study of nanocatalysts for heterogenous catalytic and electrochemical processes using pure ruthenium (Ru) with mixed-phase and platinum-based nanomaterials synthesized by continuous-flow chemistry. There are three major challenges to the application of nanomaterials in heterogenous catalytic reactions and electrocatalytic processes in acidic solution. These challenges are the following: (i) controlling the size, shape and crystallography of nanoparticles to give the best catalytic properties, (ii) scaling these nanoparticles up to a commercial quantity (kg per day) and (iii) making stable nanoparticles that can be used catalytically without degrading in acidic electrolytes. Some crucial limitations of these nanostructured materials in energy conversion and storage applications were overcome by continuous-flow chemistry. By using a continuous-flow reactor, the creation of scalable nanoparticle systems was achieved and their functionality was modified to control the nanoparticles’ physical and chemical characteristics. The nanoparticles were also tested for long-term stability, to make sure these nanoparticles were feasible under realistic working conditions. These nanoparticles are (1) shape- and crystallography-controlled ruthenium (Ru) nanoparticles, (2) size-controlled platinum-metal (Pt-M= nickel (Ni) & copper (Cu)) nanooctahedra (while maintaining morphology) and (3) core-shell platinum@ruthenium (Pt@Ru) nanoparticles where an ultrathin ruthenium shell was templated onto the platinum core. Thus, a complete experimental validation of the formation of a scalable amount of these nanoparticles and their catalytic activity and stability towards the oxygen evolution reaction (OER) in acid medium, hydrolysis of ammonia borane (AB) along with plausible explanations were provided.

  18. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  19. Structural, electrical and optical studies on ruthenium doped ZnO pellets for device applications

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Arindam [Department of Physics, National Institute of Technology Silchar, Assam 788010 (India); Department of Physics, Don Bosco College, Tura, Meghalaya 794002 (India); Kumari, Navnita [Department of Physics, Indian Institute of Technology, Delhi 110016 (India); Tewari, Sujit [Department of Physics, Karimganj College, Karimganj, Assam 788710 (India); Bhattacharjee, Ayon, E-mail: ayonbh@gmail.com [Department of Physics, National Institute of Technology Silchar, Assam 788010 (India); Department of Physics, National Institute of Technology Meghalaya, Shillong 793003 (India)

    2015-06-15

    Highlights: • Synthesis of polycrystalline ZnO by chemical route. • Change in crystallite size with increasing doping concentration. • Dopant dependency of ac conductivity. • Inter-band transitions at the fundamental edge. • Bowing/narrowing of the bandgap with doping. - Abstract: Doped and undoped specimens of nano-particulate ZnO with 0.5 wt% and 1 wt% ruthenium were prepared through a chemical route. Structural characterization of the samples performed with XRD established that all the nanoparticles are of zinc oxide having polycrystalline nature. Morphological studies were conducted using FESEM to confirm the grain size and texture. Electrical measurements showed that the ac conductivity increases with frequency but decreases with increasing ruthenium concentration, making it a potential option for device applications. It is found that the absorbance does not significantly change with doping. The above fact is further confirmed from the bandgap calculations using the reflectance graphs. A decrease of bandgap from 3.42 to 3.19 eV with increasing Ru concentration is observed making it an important and advantageous material for potential visible light photocatalytic applications involving metal oxide nanostructures.

  20. Ruthenium(II) complexes containing bidentate Schiff bases and ...

    Indian Academy of Sciences (India)

    Unknown

    expensive Schiff base ligands, in this paper, we de- scribe the synthesis, characterisation and catalytic studies of stable ruthenium(II) complexes. The general structure of the Schiff base ligands used in this study is shown in scheme 1. 2. Experimental. RuCl3.3H2O was purchased from Loba-Chemie and used as supplied.

  1. Determination of oxygen diffusion kinetics during thin film ruthenium oxidation

    NARCIS (Netherlands)

    Coloma Ribera, R.; van de Kruijs, Robbert Wilhelmus Elisabeth; Yakshin, Andrey; Bijkerk, Frederik

    2015-01-01

    In situ X-ray reflectivity was used to reveal oxygen diffusion kinetics for thermal oxidation of polycrystalline ruthenium thin films and accurate determination of activation energies for this process. Diffusion rates in nanometer thin RuO2 films were found to show Arrhenius behaviour. However, a

  2. Chelated ruthenium catalysts for Z-selective olefin metathesis.

    Science.gov (United States)

    Endo, Koji; Grubbs, Robert H

    2011-06-08

    We report the development of ruthenium-based metathesis catalysts with chelating N-heterocyclic carbene (NHC) ligands that catalyze highly Z-selective olefin metathesis. A very simple and convenient procedure for the synthesis of such catalysts has been developed. Intramolecular C-H bond activation of the NHC ligand, promoted by anion ligand substitution, forms the appropriate chelate for stereocontrolled olefin metathesis.

  3. NHC Backbone Configuration in Ruthenium-Catalyzed Olefin Metathesis

    Directory of Open Access Journals (Sweden)

    Veronica Paradiso

    2016-01-01

    Full Text Available The catalytic properties of olefin metathesis ruthenium complexes bearing N-heterocyclic carbene ligands with stereogenic centers on the backbone are described. Differences in catalytic behavior depending on the backbone configurations of symmetrical and unsymmetrical NHCs are discussed. In addition, an overview on asymmetric olefin metathesis promoted by chiral catalysts bearing C2-symmetric and C1-symmetric NHCs is provided.

  4. NHC Backbone Configuration in Ruthenium-Catalyzed Olefin Metathesis.

    Science.gov (United States)

    Paradiso, Veronica; Costabile, Chiara; Grisi, Fabia

    2016-01-20

    The catalytic properties of olefin metathesis ruthenium complexes bearing N-heterocyclic carbene ligands with stereogenic centers on the backbone are described. Differences in catalytic behavior depending on the backbone configurations of symmetrical and unsymmetrical NHCs are discussed. In addition, an overview on asymmetric olefin metathesis promoted by chiral catalysts bearing C₂-symmetric and C₁-symmetric NHCs is provided.

  5. THE SYNTHESIS AND THE REACTIVITY OF ARENE RUTHENIUM ...

    African Journals Online (AJOL)

    a

    *Corresponding author. E-mail: falloumb@refer.sn. THE SYNTHESIS AND THE REACTIVITY OF ARENE RUTHENIUM OXALATO. COMPLEXES. Cheikh Mbacké Ndiaye∗, Bamba Déthiélaw Dieng, Fatou Dieng Faye, Mohamed Gaye and. Abdoulaye Samb. Groupe de Synthèse Bioorganométallique, Laboratoire de Chimie ...

  6. Ruthenium (II)-bipyridyl with extended -system: Improved thermo ...

    Indian Academy of Sciences (India)

    Ruthenium(II)- bipyridyl with extended -system: Improved thermo-stable sensitizer for efficient and long-term durable dye sensitized solar cells ... The Density Functional Theory (DFT) and Time-Dependent DFT excited state calculations of the new sensitizer show that the first three HOMOs have t2g character with sizeable ...

  7. Kinetic, mechanistic and spectral investigation of ruthenium (III ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 117; Issue 1. Kinetic, mechanistic and spectral investigation of ruthenium (III)-catalysed oxidation of atenolol by alkaline permanganate (stopped-flow technique). Rahamatalla M Mulla Gurubasavaraj C Hiremath Sharanappa T Nandibewoor. Full Papers Volume 117 ...

  8. Kinetics and mechanism of uncatalyzed and ruthenium (III ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 128; Issue 5. Kinetics and mechanism of uncatalyzed and ruthenium(III)-catalyzed oxidation of formamidine derivative by hexacyanoferrate(III) in aqueous alkaline medium. AHMED FAWZY. Regular Article Volume 128 Issue 5 May 2016 pp 733-743 ...

  9. A new approach to synthesize supported ruthenium phosphides for hydrodesulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qingfang [Tianjin Key Laboratory of Water Environment and Resources, Tianjin Normal University, Tianjin 300387 (China); Key Laboratory of Advanced Energy Materials Chemistry (MOE), Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin 300071 (China); Wang, Zhiqiang [Tianjin Key Laboratory of Water Environment and Resources, Tianjin Normal University, Tianjin 300387 (China); Yin, Xiaoqian; Zhou, Linxi [Key Laboratory of Advanced Energy Materials Chemistry (MOE), Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin 300071 (China); Zhang, Minghui, E-mail: zhangmh@nankai.edu.cn [Key Laboratory of Advanced Energy Materials Chemistry (MOE), Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin 300071 (China); College of Chemistry and Environmental Science, Kashgar University, Kashgar 844006 (China)

    2016-02-15

    Highlights: • We bring out a new method to synthesize noble metal phosphides at low temperature. • Both RuP and Ru{sub 2}P were synthesized using triphenylphosphine as phosphorus sources. • Ru{sub 2}P was the better active phase for HDS than RuP and metal Ru. • RuP/SiO{sub 2} prepared by new method had better HDS activity to that by TPR method. - Abstract: Supported noble metal ruthenium phosphides were synthesized by one-step H{sub 2}-thermal treatment method using triphenylphosphine (TPP) as phosphorus sources at low temperatures. Two phosphides RuP and Ru{sub 2}P can be prepared by this method via varying the molar ratio of metal salt and TPP. The as-prepared phosphides were characterized by X-ray powder diffraction (XRD), low-temperature N{sub 2} adsorption, CO chemisorption and transmission electronic microscopy (TEM). The supported ruthenium phosphides prepared by new method and conventional method together with contradistinctive metallic ruthenium were evaluated in hydrodesulfurization (HDS) of dibenzothiophene (DBT). The catalytic results showed that metal-rich Ru{sub 2}P was the better active phase for HDS than RuP and metal Ru. Besides this, ruthenium phosphide catalyst prepared by new method exhibited superior HDS activity to that prepared by conventional method.

  10. Recommendation of ruthenium source for sludge batch flowsheet studies

    Energy Technology Data Exchange (ETDEWEB)

    Woodham, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-13

    Included herein is a preliminary analysis of previously-generated data from sludge batches 7a, 7b, 8, and 9 sludge simulant and real-waste testing, performed to recommend a form of ruthenium for future sludge batch simulant testing under the nitric-formic flowsheet. Focus is given to reactions present in the Sludge Receipt and Adjustment Tank cycle, given that this cycle historically produces the most changes in chemical composition during Chemical Process Cell processing. Data is presented and analyzed for several runs performed under the nitric-formic flowsheet, with consideration given to effects on the production of hydrogen gas, nitrous oxide gas, consumption of formate, conversion of nitrite to nitrate, and the removal and recovery of mercury during processing. Additionally, a brief discussion is given to the effect of ruthenium source selection under the nitric-glycolic flowsheet. An analysis of data generated from scaled demonstration testing, sludge batch 9 qualification testing, and antifoam degradation testing under the nitric-glycolic flowsheet is presented. Experimental parameters of interest under the nitric-glycolic flowsheet include N2O production, glycolate destruction, conversion of glycolate to formate and oxalate, and the conversion of nitrite to nitrate. To date, the number of real-waste experiments that have been performed under the nitric-glycolic flowsheet is insufficient to provide a complete understanding of the effects of ruthenium source selection in simulant experiments with regard to fidelity to real-waste testing. Therefore, a determination of comparability between the two ruthenium sources as employed under the nitric-glycolic flowsheet is made based on available data in order to inform ruthenium source selection for future testing under the nitric-glycolic flowsheet.

  11. Progress on ruthenium release and transport under air ingress conditions

    Energy Technology Data Exchange (ETDEWEB)

    Auvinen, A. [VTT, Espoo (Finland); Brillant, G. [IRSN DPAM/SEMIC, Cadarache (France); Davidovich, N. [ENEA, Roma (Italy); Dickson, R. [AECL, Chalk River (Canada); Ducros, G. [CEA DEN/DEC/SA3C, Cadarache (France); Dutheillet, Y. [EDF R and D, Clamart (France); Giordano, P. [IRSN DPAM/SEMIC, Cadarache (France); Kunstar, M. [KFKI AEKI, Budapest (Hungary); Kaerkelae, T. [VTT, Espoo (Finland); Mladin, M. [INR, Pitesti (Romania); Pontillon, Y. [CEA DEN/DEC/SA3C, Cadarache (France); Seropian, C. [IRSN DPAM/SEMIC, Cadarache (France); Ver, N. [KFKI AEKI, Budapest (Hungary)

    2008-12-15

    A particular concern in the event of a hypothetical severe accident is the potential release of highly radiotoxic fission product (FP) isotopes of ruthenium. The highest risk for a large quantity of these isotopes to reach the containment arises from air ingress following vessel melt-through. One work package (WP) of the source term topic of the EU 6th Framework Network of Excellence project SARNET is producing and synthesizing information on ruthenium release and transport with the aim of validating or improving the corresponding modelling in the European ASTEC severe accident analysis code. The WP includes reactor scenario studies that can be used to define conditions for new experiments. The experimental database currently being reviewed includes the following programmes: - AECL experiments conducted on fission product release in air; results are relevant to CANDU loss of end-fitting accidents; - VERCORS tests on FP release and transport conducted by CEA in collaboration with IRSN and EDF; additional tests may potentially be conducted in more oxidizing conditions in the VERDON facility; - RUSET tests by AEKI investigating ruthenium transport with and without other FP simulants; - Experiments by VTT on ruthenium transport and speciation in highly oxidizing conditions. In addition to the above, at IRSN and at ENEA modelling of fission product release and of fuel oxidation is being pursued, the latter being an essential boundary condition influencing ruthenium release. Reactor scenario studies have been carried out at INR, EDF and IRSN: calculations of air ingress scenarios with respectively ICARE/CATHARE V2; SATURNE-MAAP; and ASTEC codes provided first insights of thermal-hydraulic conditions that the fuel may experience after lower head vessel failure. This paper summarizes the status of this work and plans for the future.

  12. Effect of the ruthenium loading and barium addition on the activity of ruthenium/carbon catalysts in carbon monoxide methanation

    Directory of Open Access Journals (Sweden)

    Truszkiewicz Elżbieta

    2014-12-01

    Full Text Available A group of supported ruthenium catalysts was prepared and tested in methanation of small CO amounts (7000 ppm in hydrogen-rich streams. High surface area graphitized carbon (484 m2/g was used as a support for ruthenium and RuCl3 was used as a Ru precursor. Some of the Ru/C systems were additionally doped with barium (Ba(NO32 was barium precursor. The catalysts were characterized by the chemisorption technique using CO as an adsorbate. To determine the resistance of the catalysts to undesired carbon support methanation, the TG-MS experiments were performed. They revealed that the barium addition inhibits support losses. The studies of CO methanation (fl ow reactor, atmospheric pressure have shown that some of the supported ruthenium catalysts exhibit high activities referred to the metal mass. The catalytic properties of ruthenium proved to be dependent on metal dispersion. Some of the Ru/C and Ba-Ru/C systems exhibit higher activity in CO hydrogenation than the commercial nickel-based catalyst.

  13. Comparison of three types of XPAD3.2/CdTe single chip hybrids for hard X-ray applications in material science and biomedical imaging

    Science.gov (United States)

    Buton, C.; Dawiec, A.; Graber-Bolis, J.; Arnaud, K.; Bérar, J. F.; Blanc, N.; Boudet, N.; Clémens, J. C.; Debarbieux, F.; Delpierre, P.; Dinkespiler, B.; Gastaldi, T.; Hustache, S.; Morel, C.; Pangaud, P.; Perez-Ponce, H.; Vigeolas, E.

    2014-09-01

    The CHIPSPECT consortium aims at building a large multi-modules CdTe based photon counting detector for hard X-ray applications. For this purpose, we tested nine XPAD3.2 single chip hybrids in various configurations (i.e. Ohmic vs. Schottky contacts or electrons vs. holes collection mode) in order to select the most performing and best suited configuration for our experimental requirements. Measurements have been done using both X-ray synchrotron beams and 241Am source. Preliminary results on the image quality, calibration, stability, homogeneity and linearity of the different types of detectors are presented.

  14. Comparison of three types of XPAD3.2/CdTe single chip hybrids for hard X-ray applications in material science and biomedical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Buton, C., E-mail: clement.buton@synchrotron-soleil.fr [Synchrotron SOLEIL, L´Orme des Merisiers, Saint-Aubin — BP 48 91192, Gif-sur-Yvette Cedex (France); Dawiec, A. [Synchrotron SOLEIL, L´Orme des Merisiers, Saint-Aubin — BP 48 91192, Gif-sur-Yvette Cedex (France); Graber-Bolis, J.; Arnaud, K. [CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille (France); Bérar, J.F.; Blanc, N.; Boudet, N. [Université Grenoble Alpes, Institut NÉEL, F-38042 Grenoble (France); CNRS, Institut NÉEL, F-38042 Grenoble (France); Clémens, J.C.; Debarbieux, F. [CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille (France); Delpierre, P.; Dinkespiler, B. [imXPAD SAS — Espace Mistral, Athélia IV, 297 avenue du Mistral, 13600 La Ciotat (France); Gastaldi, T. [CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille (France); Hustache, S. [Synchrotron SOLEIL, L´Orme des Merisiers, Saint-Aubin — BP 48 91192, Gif-sur-Yvette Cedex (France); Morel, C.; Pangaud, P. [CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille (France); Perez-Ponce, H. [imXPAD SAS — Espace Mistral, Athélia IV, 297 avenue du Mistral, 13600 La Ciotat (France); Vigeolas, E. [CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille (France)

    2014-09-11

    The CHIPSPECT consortium aims at building a large multi-modules CdTe based photon counting detector for hard X-ray applications. For this purpose, we tested nine XPAD3.2 single chip hybrids in various configurations (i.e. Ohmic vs. Schottky contacts or electrons vs. holes collection mode) in order to select the most performing and best suited configuration for our experimental requirements. Measurements have been done using both X-ray synchrotron beams and {sup 241}Am source. Preliminary results on the image quality, calibration, stability, homogeneity and linearity of the different types of detectors are presented.

  15. Ruthenium(III Chloride Catalyzed Acylation of Alcohols, Phenols, and Thiols in Room Temperature Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Mingzhong Cai

    2009-09-01

    Full Text Available Ruthenium(III chloride-catalyzed acylation of a variety of alcohols, phenols, and thiols was achieved in high yields under mild conditions (room temperature in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]. The ionic liquid and ruthenium catalyst can be recycled at least 10 times. Our system not only solves the basic problem of ruthenium catalyst reuse, but also avoids the use of volatile acetonitrile as solvent.

  16. Thermodynamic hardness and the maximum hardness principle

    Science.gov (United States)

    Franco-Pérez, Marco; Gázquez, José L.; Ayers, Paul W.; Vela, Alberto

    2017-08-01

    An alternative definition of hardness (called the thermodynamic hardness) within the grand canonical ensemble formalism is proposed in terms of the partial derivative of the electronic chemical potential with respect to the thermodynamic chemical potential of the reservoir, keeping the temperature and the external potential constant. This temperature dependent definition may be interpreted as a measure of the propensity of a system to go through a charge transfer process when it interacts with other species, and thus it keeps the philosophy of the original definition. When the derivative is expressed in terms of the three-state ensemble model, in the regime of low temperatures and up to temperatures of chemical interest, one finds that for zero fractional charge, the thermodynamic hardness is proportional to T-1(I -A ) , where I is the first ionization potential, A is the electron affinity, and T is the temperature. However, the thermodynamic hardness is nearly zero when the fractional charge is different from zero. Thus, through the present definition, one avoids the presence of the Dirac delta function. We show that the chemical hardness defined in this way provides meaningful and discernible information about the hardness properties of a chemical species exhibiting integer or a fractional average number of electrons, and this analysis allowed us to establish a link between the maximum possible value of the hardness here defined, with the minimum softness principle, showing that both principles are related to minimum fractional charge and maximum stability conditions.

  17. Study on volatilization mechanism of ruthenium tetroxide from nitrosyl ruthenium nitrate by using mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Tetsuya, E-mail: tkato@criepi.denken.or.jp [Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry, 2-11-1 Iwado-kita, Komae-shi, Tokyo 201-8511 (Japan); Usami, Tsuyoshi; Tsukada, Takeshi [Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry, 2-11-1 Iwado-kita, Komae-shi, Tokyo 201-8511 (Japan); Shibata, Yuki; Kodama, Takashi [Safety Technology Division, Japan Nuclear Fuel Ltd., Obuchi, Rokkasho-mura, Aomori 039-3212 (Japan)

    2016-10-15

    In a cooling malfunction accident of a high-level liquid waste (HLLW) tank, behavior of ruthenium (Ru) attracts much attention, since Ru could be oxidized to a volatile chemical form in the boiling and drying of HLLW, and part of radioactive Ru can potentially be released to the environment. In this study, nitrosyl Ru nitrate (Ru(NO)(NO{sub 3}){sub 3}) dissolved in nitric acid (HNO{sub 3}), which is commonly contained in a simulated HLLW, was dried and heated up to 723 K, and the evolved gas was introduced into a mass spectrometer. The well-known volatile species, ruthenium tetroxide (RuO{sub 4}) was detected in a temperature range between 390 K and 500 K with the peak top around 440 K. Various gases such as HNO{sub 3}, nitrogen dioxide (NO{sub 2}), nitrogen monoxide (NO) also evolved due to evaporation of the nitric acid and decomposition of the nitrate ions. The ion current of RuO{sub 4} seems to increase with the increasing decomposition of nitrate, while the evaporation of HNO{sub 3} decreases. More volatilization of RuO{sub 4} was observed from the HNO{sub 3} solution containing not only Ru(NO)(NO{sub 3}){sub 3} but also cerium nitrate (Ce(NO{sub 3}){sub 3}·6H{sub 2}O) which was added for extra supply of nitrate ion, compared with that from the HNO{sub 3} solution containing only Ru(NO)(NO{sub 3}){sub 3}. These experimental results suggest that Ru could be oxidized to form RuO{sub 4} by the nitrate ion as well as HNO{sub 3}. - Graphical abstract: Ion current intensities of the mass numbers corresponding to O, NO, O{sub 2}, NO{sub 2}, HNO{sub 3}, and RuO{sub 4} obtained in mass spectrometry for dried nitric acid solution containing Ru(NO)(NO{sub 3}){sub 3}. Heating rate: 5 K min{sup −1}, sample solution weight: 6.61 mg, contained Ru weight: 0.56 mg. The ion current of RuO{sub 4} increases with the increasing decomposition of nitrate, while the evaporation of HNO{sub 3} decreases. - Highlights: • Nitrosyl Ru nitrate (Ru(NO)(NO{sub 3}){sub 3}) dissolved in

  18. Effect of nitrogen compounds on transport of ruthenium through the RCS.

    Science.gov (United States)

    Kajan, Ivan; Kärkelä, Teemu; Auvinen, Ari; Ekberg, Christian

    2017-01-01

    Ruthenium is a fission product that can be released from the fuel in case of a severe nuclear accident. In this work the impact of the atmosphere composition, including air radiolysis products, on the transport of ruthenium through a primary circuit was examined. Experiments were performed at temperatures 1300, 1500 and 1700 K in a slightly humid air. In the experiments significant effect of nitrogen oxides (N2O, NO2) and nitric acid on the ruthenium chemistry in the model primary circuit was observed. The obtained results indicate a strong effect of air radiolysis products on the quantity partitioning of transported ruthenium to gaseous and aerosol compounds.

  19. Template-Free Synthesis of Ruthenium Oxide Nanotubes for High-Performance Electrochemical Capacitors.

    Science.gov (United States)

    Kim, Ji-Young; Kim, Kwang-Heon; Kim, Hyun-Kyung; Park, Sang-Hoon; Roh, Kwang Chul; Kim, Kwang-Bum

    2015-08-05

    One-dimensional, hydrous ruthenium oxide nanotubes (RuO2·1.84H2O) have been successfully achieved using a template-free, microwave-hydrothermal process. These were found to be amorphous in nature and have a large specific surface area of 250 m(2)·g(-1), producing a specific and volumetric capacitance of 511 F·g(-1) and 531 F·cm(-3), respectively, at a discharging current density of 0.5 A·g(-1). When used as an electrode material in an electrochemical capacitor or ultracapacitor, they produced a significant improvement in capacitance, rate capability, and cyclability that can be attributed to the hollow nature of tubes allowing greater contact between the active surface of the electrode and the electrolyte.

  20. Control of ruthenium oxide nanorod length in reactive sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Cross, Michael W [School of Engineering, Electrical Engineering Program, University of Vermont, Burlington, VT 05405 (United States); Varhue, Walter J [School of Engineering, Electrical Engineering Program, University of Vermont, Burlington, VT 05405 (United States); Hitt, Darren L [School of Engineering, Mechanical Engineering Program, University of Vermont, Burlington, VT 05405 (United States); Adams, Edward [IBM Microelectronics, Essex Junction, VT 05452 (United States)

    2008-01-30

    Ruthenium oxide nanorods have been grown on Si wafer substrates under a variety of pre-existing surface conditions by reactive radio frequency sputtering in an electron cyclotron resonant plasma process. Nanorod formation by this method is fast relative to that observed in other processes reported in the literature, with nucleation being the rate determining step. Growth in the axial direction is limited by the availability of ruthenium precursors which competes with their consumption in the lateral growth of the nanorods. The availability of Ru precursors at the top of the nanorods can be controlled by surface diffusion and therefore substrate temperature. The ultimate length of the nanorods is determined by the mole fraction of oxygen used in the reactor ambient through the production of mobile Ru hyperoxide precursors. The results of this investigation show the way to develop a process for producing a high density field of nanorods with a specified length.

  1. Hydrogen and oxygen adsorption stoichiometries on silica supported ruthenium nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Berthoud, Romain; Delichere, Pierre; Gajan, David; Lukens, Wayne; Pelzer, Katrin; Basset, Jean-Marie; Candy, Jean-Pierre; Coperet, Christophe

    2008-12-01

    Treatment under H{sub 2} at 300 C of Ru(COD)(COT) dispersed on silica yields 2 nm ruthenium nanoparticles, [Ru{sub p}/SiO{sub 2}], according to EXAFS, HRTEM and XPS. H{sub 2} adsorption measurements on [Ru{sub p}/SiO{sub 2}] in the absence of O{sub 2} show that Ru particles adsorb up to ca. 2 H per surface ruthenium atoms (2H/Ru{sub s}) on various samples; this technique can therefore be used to measure the dispersion of Ru particles. In contrast, O{sub 2} adsorption on [Ru{sub p}/SiO{sub 2}] leads to a partial oxidation of the bulk at 25 C, to RuO{sub 2} at 200 C and to sintering upon further reduction under H{sub 2}, showing that O{sub 2} adsorption cannot be used to measure the dispersion of Ru particles.

  2. Recent Advancements in Stereoselective Olefin Metathesis Using Ruthenium Catalysts

    Directory of Open Access Journals (Sweden)

    T. Patrick Montgomery

    2017-03-01

    Full Text Available Olefin metathesis is a prevailing method for the construction of organic molecules. Recent advancements in olefin metathesis have focused on stereoselective transformations. Ruthenium olefin metathesis catalysts have had a particularly pronounced impact in the area of stereoselective olefin metathesis. The development of three categories of Z-selective olefin metathesis catalysts has made Z-olefins easily accessible to both laboratory and industrial chemists. Further design enhancements to asymmetric olefin metathesis catalysts have streamlined the construction of complex molecules. The understanding gained in these areas has extended to the employment of ruthenium catalysts to stereoretentive olefin metathesis, the first example of a kinetically E-selective process. These advancements, as well as synthetic applications of the newly developed catalysts, are discussed.

  3. Chelated Ruthenium Catalysts for Z-Selective Olefin Metathesis

    OpenAIRE

    Endo, Koji; Grubbs, Robert H

    2011-01-01

    We report the development of ruthenium-based metathesis catalysts with chelating N-heterocyclic carbene (NHC) ligands which catalyze highly Z-selective olefin metathesis. A very simple and convenient synthetic procedure of such a catalyst has been developed. An intramolecular C-H bond activation of the NHC ligand, which is promoted by anion ligand substitution, forms the appropriate chelate for stereo- controlled olefin metathesis.

  4. Recent Advancements in Stereoselective Olefin Metathesis Using Ruthenium Catalysts

    OpenAIRE

    T. Patrick Montgomery; Johns, Adam M.; Grubbs, Robert H

    2017-01-01

    Olefin metathesis is a prevailing method for the construction of organic molecules. Recent advancements in olefin metathesis have focused on stereoselective transformations. Ruthenium olefin metathesis catalysts have had a particularly pronounced impact in the area of stereoselective olefin metathesis. The development of three categories of Z-selective olefin metathesis catalysts has made Z-olefins easily accessible to both laboratory and industrial chemists. Further design enhancements to as...

  5. Allenyl esters as quenching agents for ruthenium olefin metathesis catalysts.

    Science.gov (United States)

    Roy, Animesh; Silvestri, Maximilian A; Hall, Robert A; Lepore, Salvatore D

    2017-01-04

    In the attempt to synthesize substituted allenyl esters through a metathesis coupling of unsubstituted allenyl esters and alkenes using a variety of ruthenium catalysts, it was discovered that allenyl esters themselves cleanly arrested the activity of the catalysts. Further studies suggests possible utility of allene esters as general quenching agents for metathesis reactions. To explore this idea, several representative olefin metathesis reactions, including ring closing, were successfully terminated by the addition of simple allenyl esters for more convenient purification.

  6. Mitochondria Targeted Protein-Ruthenium Photosensitizer for Efficient Photodynamic Applications

    OpenAIRE

    Chakrabortty, Sabyasachi; Agrawalla, Bikram Keshari; Stumper, Anne; Vegi, Naidu M; Fischer, Stephan; Reichardt, Christian; K?gler, Michael; Dietzek, Benjamin; Feuring-Buske, Michaela; Buske, Christian; Rau, Sven; Weil, Tanja

    2017-01-01

    Organelle-targeted photosensitization represents a promising approach in photodynamic therapy where the design of the active photosensitizer (PS) is very crucial. In this work, we developed a macromolecular PS with multiple copies of mitochondria-targeting groups and ruthenium complexes that displays highest phototoxicity toward several cancerous cell lines. In particular, enhanced anticancer activity was demonstrated in acute myeloid leukemia cell lines, where significant impairment of proli...

  7. Study of 6-cyclic -perimeter hydrocarbon ruthenium complexes ...

    Indian Academy of Sciences (India)

    1,3-dione (dppdH) ligands yielded new water soluble 6-arene ruthenium(II) complexes of the formulation [(6-arene)Ru(2-N-O-pppdH)Cl]+ (arene = C6H6 1, pPrC6H4Me 2, C6Me6 3) and [(6-arene)2Ru2(4-N-O-dppd)Cl2]+ (arene ...

  8. Medium effect on cyclohexene hydrocarbomethoxylation catalyzed by ruthenium (III) chloride

    OpenAIRE

    Sevostyanova N.; Batashev S.

    2016-01-01

    This paper presents influence of some solvents on cyclohexene hydrocarbomethoxylation catalyzed by ruthenium(III) chloride. The objective of the work was contained in the determination of medium influence on the reaction rate and yield of product — methyl cyclohexanecarboxylate. The kinetic method was used as the main method of investigation. The gas–liquid chromatography method was used to analyze the reaction mass. Influence of methanol, toluene, acetone and water on the hydrocarmothoxy...

  9. Mononuclear and Heterotrinuclear Ruthenium Complexes: Synthesis and Water Oxidation Activity

    OpenAIRE

    Mognon, Lorenzo

    2015-01-01

    Artificial photosynthesis constitutes an intriguing alternative to fossil fuels, and the water oxidation reaction is considered the bottleneck for the achievement of an efficient device to perform it. Extensive research has been carried out, and is still ongoing, to identify the properties and mechanisms that define a good water oxidation catalyst. Ruthenium complexes have shown to be valid candidates for this task. This work presents the synthesis and characterization of multiple mononuclear...

  10. Crystal Structure of Ruthenium Phthalocyanine with Diaxial Monoatomic Ligand: Bis(TriphenylphosphineIminium Dichloro(Phthalocyaninato(2-Ruthenium(III

    Directory of Open Access Journals (Sweden)

    Derrick Ethelbhert Yu

    2013-01-01

    Full Text Available Axially-ligated iron phthalocyanines have been found to be good molecular conductors with giant negative magnetoresistance (GNMR which originates from a strong intramolecular π-d interaction between the metal and phthalocyanine. Ab initio theoretical calculations showed that substitution of ruthenium into the phthalocyanine complex would result in a significant increase in the π-d interaction of the system, potentially intensifying GNMR. This paper presents the crystal preparation and X-ray structural characterization of bis(triphenylphosphineiminium dichloro(phthalocyaninato(2-ruthenium(III, PNP [RuIII(Pc2−Cl2]. It is observed that [RuIII(Pc2−Cl2] system has a symmetric planar RuPc unit with perpendicular axial ligands which results in a unidirectional and uniform solid-state arrangement, suitable for π-d interaction-based molecular conductors with potentially exceptional GNMR.

  11. Analysis of the cytotoxic effects of ruthenium-ketoconazole and ruthenium-clotrimazole complexes on cancer cells.

    Science.gov (United States)

    Robles-Escajeda, Elisa; Martínez, Alberto; Varela-Ramirez, Armando; Sánchez-Delgado, Roberto A; Aguilera, Renato J

    2013-12-01

    Ruthenium-based compounds have intriguing anti-cancer properties, and some of these novel compounds are currently in clinical trials. To continue the development of new metal-based drug combinations, we coupled ruthenium (Ru) with the azole compounds ketoconazole (KTZ) and clotrimazole (CTZ), which are well-known antifungal agents that also display anticancer properties. We report the activity of a series of 12 Ru-KTZ and Ru-CTZ compounds against three prostate tumor cell lines with different androgen sensitivity, as well as cervical cancer and lymphoblastic lymphoma cell lines. In addition, human cell lines were used to evaluate the toxicity against non-transformed cells and to establish selectivity indexes. Our results indicate that the combination of ruthenium and KTZ/CTZ in a single molecule results in complexes that are more cytotoxic than the individual components alone, displaying in some cases low micromolar CC50 values and high selectivity indexes. Additionally, all compounds are more cytotoxic against prostate cell lines with lower cytotoxicity against non-transformed epidermal cell lines. Some of the compounds were found to primarily induce cell death via apoptosis yet weakly interact with DNA. Our studies also demonstrate that the cytotoxicity induced by our Ru-based compounds is not directly related to their ability to interact with DNA.

  12. Macroindentation hardness measurement-Modernization and applications.

    Science.gov (United States)

    Patel, Sarsvat; Sun, Changquan Calvin

    2016-06-15

    In this study, we first developed a modernized indentation technique for measuring tablet hardness. This technique is featured by rapid digital image capture, using a calibrated light microscope, and precise area-determination. We then systematically studied effects of key experimental parameters, including indentation force, speed, and holding time, on measured hardness of a very soft material, hydroxypropyl cellulose, and a very hard material, dibasic calcium phosphate, to cover a wide range of material properties. Based on the results, a holding period of 3min at the peak indentation load is recommended to minimize the effect of testing speed on H. Using this method, we show that an exponential decay function well describes the relationship between tablet hardness and porosity for seven commonly used pharmaceutical powders investigated in this work. We propose that H and H at zero porosity may be used to quantify the tablet deformability and powder plasticity, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Quantification of a Heterogeneous Ruthenium Catalyst on Carbon-black using ADF Imaging

    Science.gov (United States)

    Varambhia, A. M.; Jones, L.; Nellist, P. D.; Lozano-Perez, S.; Ozkaya, D.

    2015-10-01

    Using recent developments in ADF quantification techniques, we utilise a rapid atom counting procedure to document the evolution of a heterogeneous ruthenium catalyst on carbon black. Selected areas of the ruthenium catalyst were imaged for approximately 15 minutes. The imaged areas show that the Ru wets the support forming a thin amorphous layer that transforms to a crystalline layer under beam irradiation.

  14. The mechanism of activation of amidobenzylidene ruthenium chelates - latent catalysts of olefin metathesis.

    Science.gov (United States)

    Rogalski, Szymon; Żak, Patrycja; Tadeuszyk, Natalia; Pyta, Krystian; Przybylski, Piotr; Pietraszuk, Cezary

    2017-01-24

    Amidobenzylidene ruthenium chelates - latent catalysts of olefin metathesis can be easily activated by the addition of Brønsted or Lewis acids. Their activation in the presence of hydrogen chloride involves the formation of catalytically active trans-dichloro carbamatobenzylidene ruthenium chelates.

  15. Ruthenium on chitosan: A recyclable heterogeneous catalyst for aqueous hydration of nitriles to amides

    Science.gov (United States)

    Ruthenium has been immobilized over chitosan by simply stirring an aqueous suspension of chitosan in water with ruthenium chloride and has been utilized for the oxidation of nitriles to amides; the hydration of nitriles occurs in high yield and excellent selectivity, which procee...

  16. Thermochemistry of Ruthenium Oxyhydroxide Species and Their Impact on Volatile Speciations in Severe Nuclear Accident Conditions.

    Science.gov (United States)

    Miradji, Faoulat; Virot, François; Souvi, Sidi; Cantrel, Laurent; Louis, Florent; Vallet, Valérie

    2016-02-04

    Literature thermodynamic data of ruthenium oxyhydroxides reveal large uncertainties in some of the standard enthalpies of formation, motivating the use of high-level relativistic correlated quantum chemical methods to reduce the level of discrepancies. Reaction energies leading to the formation of all possible oxyhydroxide species RuOx(OH)y(H2O)z have been calculated for a series of reactions combining DFT (TPSSh-5%HF) geometries and partition functions, CCSD(T) energies extrapolated to the complete basis set limits. The highly accurate ab initio thermodynamic data were used as input data of thermodynamic equilibrium computations to derive the speciation of gaseous ruthenium species in the temperature, pressure and concentration conditions of severe nuclear accidents occurring in pressurized water reactors. At temperatures lower than 1000 K, gaseous ruthenium tetraoxide is the dominating species, between 1000 and 2000 K ruthenium trioxide becomes preponderant, whereas at higher temperatures gaseous ruthenium oxide, dioxide and even Ru in gaseous phase are formed. Although earlier studies predicted the formation of oxyhydroxides in significant quantities, the use of highly accurate ab initio thermodynamic data for ruthenium gaseous species leads to a more reliable inventory of gaseous ruthenium species in which gaseous oxyhydroxide ruthenium molecules are formed only in negligible amounts.

  17. Magnetic Silica-Supported Ruthenium Nanoparticles: An Efficient Catalyst for Transfer Hydrogenation of Carbonyl Compounds

    Science.gov (United States)

    One-pot synthesis of ruthenium nanoparticles on magnetic silica is described which involve the in situ generation of magnetic silica (Fe3O4@ SiO2) and ruthenium nano particles immobilization; the hydration of nitriles and transfer hydrogenation of carbonyl compounds occurs in hi...

  18. Synthesis and catalytic activity of histidine-based NHC ruthenium complexes.

    Science.gov (United States)

    Monney, Angèle; Venkatachalam, Galmari; Albrecht, Martin

    2011-03-28

    Main-chain C,N-protected histidine has been successfully alkylated at both side-chain nitrogens. The corresponding histidinium salt was metallated with ruthenium(II) by a transmetalation procedure, thus providing histidine-derived NHC ruthenium complexes. These bio-inspired complexes show appreciable activity in the catalytic transfer hydrogenation of ketones.

  19. Assisted Tandem Catalysis : Metathesis Followed by Asymmetric Hydrogenation from a Single Ruthenium Source

    NARCIS (Netherlands)

    Renom-Carrasco, Marc; Gajewski, Piotr; Pignataro, Luca; de Vries, Johannes G.; Piarulli, Umberto; Gennari, Cesare; Lefort, Laurent

    2015-01-01

    Here we report the first example of a tandem metathesis-asymmetric hydrogenation protocol where the prochiral olefin generated by metathesis is hydrogenated with high enantioselectivity by an in situ formed chiral ruthenium catalyst. We show that either the ruthenium metathesis catalysts or the

  20. Study of hot hardness characteristics of tool steels

    Science.gov (United States)

    Chevalier, J. L.; Dietrich, M. W.; Zaretsky, E. V.

    1972-01-01

    Hardness measurements of tool steel materials in electric furnace at elevated temperatures and low oxygen environment are discussed. Development of equation to predict short term hardness as function of intial room temperature hardness of steel is reported. Types of steel involved in the process are identified.

  1. INFLUENCE OF COOLING CONDITIONS AND THE SIZE OF STOCK MATERIAL DURING CASTING OF TOOL STEEL ON CAPABILITY TO THE SUBSEQUENT THERMAL HARD-FACING

    Directory of Open Access Journals (Sweden)

    V. N. Fedulov

    2016-01-01

    Full Text Available Influence of cooling conditions and the size of stock material of instrumental steel 4H5MF1S on сability to surface hardening after high-temperature tempering at 500–650 °C is investigated. Comparison with hardening of forgings is given.

  2. The Development and Study of Surface Bound Ruthenium Organometallic Complexes

    Science.gov (United States)

    Abbott, Geoffrey Reuben

    The focus of this project has been on the use of mono-diimine ruthenium organometallic complexes, of the general structure [H(Ru)(CO)(L)2(L') 2][PF6] (L=PPh3, DPPENE and L'=Bpy, DcBpy, MBpyC, Phen, AminoPhen) bound to surfaces as luminescent probes. Both biological and inorganic/organic hybrid surfaces have been studied. The complexes were characterized both bound and unbound using standard analytical techniques such as NMR, IR and X-ray crystallography, as well as through several photophysical methods as well. Initially the study focused on how the photophyscial properties of the complexes were affected by incorporation into biological membranes. It was found that by conjugating the probes to a more rigid cholesterol moiety that luminescence was conserved, compared to conjugation with a far more flexible lipid moiety, where luminescence was either lost or reduced. Both the cholesterol and lipid conjugates were able to insert into a lipid membrane, and in the more rigid environment some of the lipid conjugates regained some of their luminescence, but often blue shifted and reduced, depending on the conjugation site. Silica Polyamine Composites (SPCs) were a hybrid material developed in the Rosenberg Lab as useful metal separation materials, that could be easily modified, and had several benefits over current commercially available polymers, or inorganic materials. These SPCs also provided an opportunity for the development of a heterogeneous platform for luminescent complexes as either catalysts or sensors. Upon binding of the luminescent Ru complexes to the surface no loss, or major change in luminescence was seen, however, when bound to the rigid surface a significant increase in excited state lifetime was measured. It is likely that through binding and interacting with the surface that the complexes lost non-radiative decay pathways, resulting in the increase in lifetime, however, these interactions do not seem to affect the energy level of the MLCT band in a

  3. Radiation Hardness Assurance (RHA) Guideline

    Science.gov (United States)

    Campola, Michael J.

    2016-01-01

    Radiation Hardness Assurance (RHA) consists of all activities undertaken to ensure that the electronics and materials of a space system perform to their design specifications after exposure to the mission space environment. The subset of interests for NEPP and the REAG, are EEE parts. It is important to register that all of these undertakings are in a feedback loop and require constant iteration and updating throughout the mission life. More detail can be found in the reference materials on applicable test data for usage on parts.

  4. Ruthenium(0) nanoclusters stabilized by a Nanozeolite framework: isolable, reusable, and green catalyst for the hydrogenation of neat aromatics under mild conditions with the unprecedented catalytic activity and lifetime.

    Science.gov (United States)

    Zahmakiran, Mehmet; Tonbul, Yalçin; Ozkar, Saim

    2010-05-12

    The hydrogenation of aromatics is a ubiquitous chemical transformation used in both the petrochemical and specialty industry and is important for the generation of clean diesel fuels. Reported herein is the discovery of a superior heterogeneous catalyst, superior in terms of catalytic activity, selectivity, and lifetime in the hydrogenation of aromatics in the solvent-free system under mild conditions (at 25 degrees C and 42 +/- 1 psig initial H(2) pressure). Ruthenium(0) nanoclusters stabilized by a nanozeolite framework as a new catalytic material is reproducibly prepared from the borohydride reduction of a colloidal solution of ruthenium(III)-exchanged nanozeolites at room temperature and characterized by using ICP-OES, XRD, XPS, DLS, TEM, HRTEM, TEM/EDX, mid-IR, far-IR, and Raman spectroscopy. The resultant ruthenium(0) nanoclusters hydrogenate neat benzene to cyclohexane with 100% conversion under mild conditions (at 25 degrees C and 42 +/- 1 psig initial H(2) pressure) with record catalytic activity (initial TOF = 5430 h(-1)) and lifetime (TTO = 177 200). They provide exceptional catalytic activity not only in the hydrogenation of neat benzene but also in the solvent-free hydrogenation of methyl substituted aromatics such as toluene, o-xylene, and mesitylene under otherwise identical conditions. Moreover, they are an isolable, bottleable, and reusable catalyst in the hydrogenation of neat aromatics. When the isolated ruthenium(0) nanoclusters are reused, they retain 92% of their initial catalytic activity even for the third run in the hydrogenation of neat benzene under the same conditions as those of the first run. The work reported here also includes (i) far-infrared spectroscopic investigation of nanozeolite, ruthenium(III)-exchanged-nanozeolite, and ruthenium(0) nanoclusters stabilized by a nanozeolite framework, indicating that the host framework remains intact after the formation of a nanozeolite framework stabilized ruthenium(0) nanoclusters; (ii) the

  5. Simultaneous determination of rhodium and ruthenium by high-resolution continuum source graphite furnace atomic absorption spectrometry

    Science.gov (United States)

    Zambrzycka-Szelewa, Elżbieta; Lulewicz, Marta; Godlewska-Żyłkiewicz, Beata

    2017-07-01

    In the present paper a fast, simple and sensitive analytical method for simultaneous determination of rhodium and ruthenium by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS) was developed. Among six pairs of absorption atomic lines of Rh and Ru, which are close enough to enable their simultaneous detection, two pairs were selected for further studies. Best results were obtained for measurements of the resonance line of rhodium at 343.489 nm and the adjacent secondary line of ruthenium at 343.674 nm (23% intensity of this line). For evaluated lines, the absorbance values were obtained using three pixels. The pyrolysis and atomization temperatures were 1200 °C and 2600 °C, respectively. Under these conditions the limits of detection achieved for Rh and Ru were found to be 1.0 μg L- 1 and 1.9 μg L- 1, respectively. The characteristic mass was 12.9 pg for Rh and 71.7 pg for Ru. Repeatability of the results expressed as a relative standard deviation was typically below 6%. The trueness of the method was confirmed by analysis of the certified reference material - platinum ore (SARM 76). The recovery of Rh and Ru from the platinum ore was 93.0 ± 4.6% and 90.1 ± 2.5%, respectively. The method was successfully applied to the direct simultaneous determination of trace amounts of rhodium and ruthenium in spiked river water, road runoff, and municipal sewage. Separation of interfering matrix on cation exchange resin was required before analysis of road dust and tunnel dust (CW-7) by HR-CS GFAAS.

  6. Immobilization of ruthenium phthalocyanine on silica-coated multi-wall partially oriented carbon nanotubes: Electrochemical detection of fenitrothion pesticide

    Energy Technology Data Exchange (ETDEWEB)

    Canevari, Thiago C., E-mail: tccanevari@gmail.com [Engineering School, Mackenzie Presbyterian University, 01302-907 São Paulo, SP (Brazil); Prado, Thiago M.; Cincotto, Fernando H.; Machado, Sergio A.S. [Institute of Chemistry, State University of São Paulo, P.O. Box 780, 13560-970 São Carlos, SP (Brazil)

    2016-04-15

    Highlights: • Hybrid material, SiO{sub 2}/MWCNTs containing ruthenium phthalocyanine (RuPc) synthesized in situ. • Silica containing multi-walled carbon nanotube partially oriented. • Determination of pesticide fenitrothion in orange juice. - Abstract: This paper reports on the determination of the pesticide fenitrothion using a glassy carbon electrode modified with silica-coated, multi-walled, partially oriented carbon nanotubes, SiO{sub 2}/MWCNTs, containing ruthenium phthalocyanine (RuPc) synthesized in situ. The hybrid SiO{sub 2}/MWCNTs/RuPc material was characterized by UV–vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and differential pulse voltammetry. The modified electrode showed well-defined peaks in the presence of fenitrothion in acetate buffer, pH 4.5, with a sensitivity of 0.0822 μA μM{sup −1} mm{sup −2} and a detection limit of 0.45 ppm. Notably, the modified SiO{sub 2}/MWCNTs/RuPc electrodes with did not suffer from significant influences in the presence of other organophosphorus pesticides during the determination of the fenitrothion pesticide. Moreover, this modified electrode showed excellent performance in the determination of fenitrothion in orange juice.

  7. A Modified Theoretical Model of Intrinsic Hardness of Crystalline Solids

    Science.gov (United States)

    Dai, Fu-Zhi; Zhou, Yanchun

    2016-01-01

    Super-hard materials have been extensively investigated due to their practical importance in numerous industrial applications. To stimulate the design and exploration of new super-hard materials, microscopic models that elucidate the fundamental factors controlling hardness are desirable. The present work modified the theoretical model of intrinsic hardness proposed by Gao. In the modification, we emphasize the critical role of appropriately decomposing a crystal to pseudo-binary crystals, which should be carried out based on the valence electron population of each bond. After modification, the model becomes self-consistent and predicts well the hardness values of many crystals, including crystals composed of complex chemical bonds. The modified model provides fundamental insights into the nature of hardness, which can facilitate the quest for intrinsic super-hard materials. PMID:27604165

  8. Hardness Tester for Polyur

    Science.gov (United States)

    Hauser, D. L.; Buras, D. F.; Corbin, J. M.

    1987-01-01

    Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

  9. Analysis of Hard Thin Film Coating

    Science.gov (United States)

    Shen, Dashen

    1998-01-01

    MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  10. Thermal properties of ruthenium alkylidene-polymerized dicyclopentadiene

    Directory of Open Access Journals (Sweden)

    Yuval Vidavsky

    2015-08-01

    Full Text Available Differential scanning calorimetry (DSC analysis of ring opening methatesis polymerization (ROMP derived polydicyclopentadiene (PDCPD revealed an unexpected thermal behavior. A recurring exothermic signal can be observed in the DSC analysis after an elapsed time period. This exothermic signal was found to be proportional to the resting period and was accompanied by a constant increase in the glass-transition temperature. We hypothesize that a relaxation mechanism within the cross-linked scaffold, together with a long-lived stable ruthenium alkylidene species are responsible for the observed phenomenon.

  11. Radiation related complications after ruthenium plaque radiotherapy of uveal melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Summanen, P.; Immonen, I.; Kivela, T.; Tommila, P.; Tarkkanen, A. [Helsinki Univ. Central Hospital (Finland). Meilahti Clinic; Heikkonen, J. [Helsinki Univ. (Finland). Dept of Radiotherapy and Oncology

    1996-08-01

    The aims were to analyse radiation related complications and secondary enucleation after irradiation of malignant uveal melanoma with ruthenium-106 plaques. A series of 100 consecutive eyes irradiated in 1981-91 was analysed using the life table method and the Cox proportional hazards model. The 3 and 5 year probabilities of being without radiation cataract were 73% and 63%, without neovascular glaucoma 91% and 81%, without vitreous haemorrhage 83% and 74%, without radiation maculopathy 85% and 70%, and without radiation optic neuropathy 90% and 88%, respectively. (Author).

  12. Ruthenium-Catalyzed Dehydrogenative Decarbonylation of Primary Alcohols

    DEFF Research Database (Denmark)

    Mazziotta, Andrea; Madsen, Robert

    2017-01-01

    Dehydrogenative decarbonylation of a primary alcohol involves the release of both dihydrogen and carbon monoxide to afford the one-carbon shorter product. The transformation has now been achieved with a ruthenium-catalyzed protocol by using the complex Ru(COD)Cl2 and the hindered monodentate ligand...... P(o-tolyl)3 in refluxing p-cymene. The reaction can be applied to both benzylic and long chain linear aliphatic alcohols. The intermediate aldehyde can be observed during the transformation, which is therefore believed to proceed through two separate catalytic cycles involving first dehydrogenation...... of the alcohol and then decarbonylation of the resulting aldehyde....

  13. The trans influence in mer-trichloronitridobis(triphenylarsine)ruthenium(VI)

    DEFF Research Database (Denmark)

    Magnussen, Magnus; Bendix, Jesper

    2003-01-01

    The title compound, mer-[RuCl(3)N(C(18)H(15)As)(2)], is the first structurally characterized example of a nitride complex in which ruthenium is six-coordinated to monodentate ligands only. The Ru[triple-bond]N bond length [1.6161 (15) A] is relatively long, and the trans influence of the nitride...... ligand is reflected by the difference between the Ru--Cl(trans) and Ru--Cl(cis) bond lengths [0.1234 (4) A]. The N--Ru--Cl(trans) axis is sited on a twofold axis....

  14. Short-term hot hardness characteristics of rolling-element steels

    Science.gov (United States)

    Chevalier, J. L.; Dietrich, M. W.; Zaretsky, E. V.

    1972-01-01

    Short-term hot hardness studies were performed with five vacuum-melted steels at temperatures from 294 to 887 K (70 to 1140 F). Based upon a minimum Rockwell C hardness of 58, the temperature limitation on all materials studied was dependent on the initial room temperature hardness and the tempering temperature of each material. For the same room temperature hardness, the short-term hot hardness characteristics were identical and independent of material composition. An equation was developed to predict the short-term hardness at temperature as a function of initial room temperature hardness for AISI 52100, as well as the high-speed tool steels.

  15. Ruthenium-106 brachytherapy for uveal melanomas. Preliminary results: a single institutional experience; Braquiterapia com rutenio-106 em melanomas uveais. Resultados preliminares: experiencia uni-instuticional

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Rodrigo Souza; Giordani, Adelmo Jose; Segreto, Helena Regina Comodo; Segreto, Roberto Araujo [Universidade Federal de Sao Paulo/Escola Paulista de Medicina (Unifesp/EPM), Sao Paulo, SP (Brazil). Departamento de Medicina. Setor de Radioterapia ; Erwenne, Clelia Maria; Teixeira, Luiz Fernando [Universidade Federal de Sao Paulo/Escola Paulista de Medicina (UNIFESP/EPM), Sao Paulo, SP (Brazil). Dept. de Oftalmologia]. E-mail: segreto. dmed@epm.br

    2007-03-15

    Objective: To analyze the early response of uveal melanomas in patients treated with ruthenium-106 brachytherapy. Materials And Methods: In the period between April 2002 and July 2003, 20 patients diagnosed with uveal melanoma were submitted to ruthenium-106 brachytherapy. The calculated dose delivered at the apex of the tumor ranged between 55 Gy and 100 Gy. Patients with lesions greater than 5 mm were submitted to transpupillary thermotherapy concomitantly with ophthalmic plaque insertion. Results: As regards the lesions site, 75% of the lesions were located in the choroid, 15% in the iris, and the remainder 10% in the ciliary body. In a median 19-month-follow-up, the progression-free survival for brachytherapy was 69%, and 87% for associated brachytherapy and transpupillary thermotherapy. A significant tumor height reduction was observed after treatment. No patient was submitted to enucleation. Conclusion: Our preliminary results show that ruthenium-106 brachytherapy is an appropriate method for conservative treatment of patients with uveal melanomas in terms of local management, ocular and visual acuity preservation with an acceptable complications incidence rate. (author)

  16. High-Performance, Radiation-Hard, 2-D, Near-Infrared, Avalanche Photodiode Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this STTR project we will address the radiation hardness issues using radiation hard (RH) materials. We will based on the RH material to develop our photon...

  17. Effect of nitrogen compounds on transport of ruthenium through the RCS

    OpenAIRE

    Kajan, Ivan; K?rkel?, Teemu; Auvinen, Ari; Ekberg, Christian

    2017-01-01

    Ruthenium is a fission product that can be released from the fuel in case of a severe nuclear accident. In this work the impact of the atmosphere composition, including air radiolysis products, on the transport of ruthenium through a primary circuit was examined. Experiments were performed at temperatures 1300, 1500 and 1700?K in a slightly humid air. In the experiments significant effect of nitrogen oxides (N2O, NO2) and nitric acid on the ruthenium chemistry in the model primary circuit was...

  18. Dihydrogen Phosphate Stabilized Ruthenium(0 Nanoparticles: Efficient Nanocatalyst for The Hydrolysis of Ammonia-Borane at Room Temperature

    Directory of Open Access Journals (Sweden)

    Feyyaz Durap

    2015-07-01

    Full Text Available Intensive efforts have been devoted to the development of new materials for safe and efficient hydrogen storage. Among them, ammonia-borane appears to be a promising candidate due to its high gravimetric hydrogen storage capacity. Ammonia-borane can release hydrogen on hydrolysis in aqueous solution under mild conditions in the presence of a suitable catalyst. Herein, we report the synthesis of ruthenium(0 nanoparticles stabilized by dihydrogenphosphate anions with an average particle size of 2.9 ± 0.9 nm acting as a water-dispersible nanocatalyst in the hydrolysis of ammonia-borane. They provide an initial turnover frequency (TOF value of 80 min−1 in hydrogen generation from the hydrolysis of ammonia-borane at room temperature. Moreover, the high stability of these ruthenium(0 nanoparticles makes them long-lived and reusable nanocatalysts for the hydrolysis of ammonia-borane. They provide 56,800 total turnovers and retain ~80% of their initial activity even at the fifth catalytic run in the hydrolysis of ammonia-borane at room temperature.

  19. The synthesis of novel LiNiPO4 core and Co3O4/CoO shell materials by combining them with hard-template and solvothermal routes.

    Science.gov (United States)

    Örnek, Ahmet

    2017-10-15

    Pure CoO and Co3O4 surface-modified LiNiPO4 nanoscale powders are successfully synthesized for the first time by newly elaborated hard-template and solvothermal methods. Using this extraordinary technique, LiNiPO4 particles are coated with a thin CoO or Co3O4 layer with a perfect core-shell morphology. The technique's positive contribution to electrochemistry is investigated in detail. The HR-TEM analysis proves that it possible to achieve a continuous surface coverage of about 5nm, a result that contributes towards solving the chronic electrochemical problems of high-voltage cathode material. Our data reveal that cobalt cannot be diffused into the LiNiPO4 crystal system during the calcination process and that the LiNiPO4@CoO cathode demonstrates superior cycle stability and specific capacity at relatively low rates. The LiNiPO4@CoO cathode exhibits the best electrochemical properties, achieving a discharge capacity of 149mAhg(-1) at 0.1C rate, and shows almost 82% capacity retention after 80 charge-discharge cycles. It therefore achieves partial success in terms of improving the electrochemical properties of the LiNiPO4 cathode material. This is especially crucial for energy storage with regard to electric vehicles and plug-in hybrid electric applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Hard probes 2006 Asilomar

    CERN Multimedia

    2006-01-01

    "The second international conference on hard and electromagnetic probes of high-energy nuclear collisions was held June 9 to 16, 2006 at the Asilomar Conference grounds in Pacific Grove, California" (photo and 1/2 page)

  1. New nitric oxide donors based on ruthenium complexes

    Directory of Open Access Journals (Sweden)

    C.N. Lunardi

    2009-01-01

    Full Text Available Nitric oxide (NO donors produce NO-related activity when applied to biological systems. Among its diverse functions, NO has been implicated in vascular smooth muscle relaxation. Despite the great importance of NO in biological systems, its pharmacological and physiological studies have been limited due to its high reactivity and short half-life. In this review we will focus on our recent investigations of nitrosyl ruthenium complexes as NO-delivery agents and their effects on vascular smooth muscle cell relaxation. The high affinity of ruthenium for NO is a marked feature of its chemistry. The main signaling pathway responsible for the vascular relaxation induced by NO involves the activation of soluble guanylyl-cyclase, with subsequent accumulation of cGMP and activation of cGMP-dependent protein kinase. This in turn can activate several proteins such as K+ channels as well as induce vasodilatation by a decrease in cytosolic Ca2+. Oxidative stress and associated oxidative damage are mediators of vascular damage in several cardiovascular diseases, including hypertension. The increased production of the superoxide anion (O2- by the vascular wall has been observed in different animal models of hypertension. Vascular relaxation to the endogenous NO-related response or to NO released from NO deliverers is impaired in vessels from renal hypertensive (2K-1C rats. A growing amount of evidence supports the possibility that increased NO inactivation by excess O2- may account for the decreased NO bioavailability and vascular dysfunction in hypertension.

  2. Hardness amplification in nondeterministic logspace

    OpenAIRE

    Gupta, Sushmita

    2007-01-01

    A hard problem is one which cannot be easily computed by efficient algorithms. Hardness amplification is a procedure which takes as input a problem of mild hardness and returns a problem of higher hardness. This is closely related to the task of decoding certain error-correcting codes. We show amplification from mild average case hardness to higher average case hardness for nondeterministic logspace and worst-to-average amplification for nondeterministic linspace. Finally we explore possible ...

  3. Ruthenium carbenes supported on mesoporous silicas as highly active and selective hybrid catalysts for olefin metathesis reactions under continuous flow.

    Science.gov (United States)

    Bru, Miriam; Dehn, Richard; Teles, J Henrique; Deuerlein, Stephan; Danz, Manuel; Müller, Imke B; Limbach, Michael

    2013-08-26

    In the search for a highly active and selective heterogenized metathesis catalyst, we systematically varied the pore geometry and size of various silica-based mesoporous (i.e., MCM-41, MCM-48, and SBA-15) and microporous (ZSM-5 and MWW) versus macroporous materials (D11-10 and Aerosil 200), besides other process parameters (temperature, dilution, and mean residence time). The activity and, especially, selectivity of such "linker-free" supports for ruthenium metathesis catalysts were evaluated in the cyclodimerization of cis-cyclooctene to form 1,9-cyclohexadecadiene, a valuable intermediate in the flavor and fragrance industry. The optimized material showed not only exceptionally high selectivity to the valuable product, but also turned out to be a truly heterogeneous catalyst with superior activity relative to the unsupported homogeneous complex. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Ruthenium or osmium complexes and their uses as catalysts for water oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Concepcion Corbea, Javier Jesus; Chen, Zuofeng; Jurss, Jonah Wesley; Templeton, Joseph L; Hoertz, Paul; Meyer, Thomas J

    2014-10-28

    The present invention provides ruthenium or osmium complexes and their uses as a catalyst for catalytic water oxidation. Another aspect of the invention provides an electrode and photo-electrochemical cells for electrolysis of water molecules.

  5. Ruthenium or osmium complexes and their uses as catalysts for water oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Corbea, Javier Jesus Concepcion; Chen, Zuofeng; Jurss, Jonah Wesley; Templeton, Joseph L.; Hoertz, Paul; Meyer, Thomas J.

    2013-09-03

    The present invention provides ruthenium or osmium complexes and their uses as a catalyst for catalytic water oxidation. Another aspect of the invention provides an electrode and photo-electrochemical cells for electrolysis of water molecules.

  6. Ruthenium or osmium complexes and their uses as catalysts for water oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Corbea, Javier Jesus Concepcion; Chen, Zoufeng; Jurss, Jonah Wesley; Templeton, Joseph L.; Hoertz, Paul; Meyer, Thomas J.

    2016-06-07

    The present invention provides ruthenium or osmium complexes and their uses as a catalyst for catalytic water oxidation. Another aspect of the invention provides an electrode and photo-electrochemical cells for electrolysis of water molecules.

  7. Extraction of ruthenium thiocyanate and its separation from rhodium by polyurethane foam

    Energy Technology Data Exchange (ETDEWEB)

    Al-Bazi, S.J.; Chow, A. (Manitoba Univ., Winnipeg (Canada). Dept. of Chemistry)

    1984-03-01

    Conditions for the formation and extraction of the thiocyanate complex of ruthenium are reported. Distribution coefficients of more than 10/sup 4/ and a capacity of about 0.24 mole per kg of foam were obtained. The effect of the chloride salts of various univalent cations on the extraction of Ru(SCN)/sub 6//sup 3 -/ indicated that the efficiency of ruthenium extraction depends on how well the cation fits into the polyether segment of the polyurethane foam, which agrees with the 'cation-chelation' mechanism. The separation of ruthenium and rhodium indicated that more than 95% of the rhodium remained in the aqueous phase and about 95% of the ruthenium was retained by the polyurethane foam and could be easily recovered.

  8. Efficient oxygen reduction reaction using ruthenium tetrakis(diaquaplatinum)octacarboxyphthalocyanine catalyst supported on MWCNT platform

    CSIR Research Space (South Africa)

    Maxakato, NW

    2011-02-01

    Full Text Available Electrocatalytic reduction of molecular oxygen in alkaline solution using a novel ruthenium tetrakis(diaquaplatinum) octacarboxyphthalocyanine (RuOCPcPt) electrocatalyst supported on multi-walled carbon nanotube electrode has been described. We show...

  9. Inductively Coupled Plasma Mass Spectrometry: Sample Analysis of Zirconium and Ruthenium in Metal Organic Frameworks

    Science.gov (United States)

    2018-02-01

    INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY: SAMPLE ANALYSIS OF ZIRCONIUM AND RUTHENIUM IN METAL ORGANIC...MM-YYYY) XX-02-2018 2. REPORT TYPE Final 3. DATES COVERED (From - To) Aug 2016–Aug 2017 4. TITLE AND SUBTITLE Inductively Coupled Plasma Mass...MOFs) using inductively coupled plasma mass spectrometry (ICP–MS). Specifically, the MOFs were analyzed for the zirconium-to-ruthenium ratios. The

  10. A New Homogeneous Catalyst for the Dehydrogenation of Dimethylamine Borane Starting with Ruthenium(III Acetylacetonate

    Directory of Open Access Journals (Sweden)

    Ebru Ünel Barın

    2015-06-01

    Full Text Available The catalytic activity of ruthenium(III acetylacetonate was investigated for the first time in the dehydrogenation of dimethylamine borane. During catalytic reaction, a new ruthenium(II species is formed in situ from the reduction of ruthenium(III and characterized using UV-Visible, Fourier transform infrared (FTIR, 1H NMR, and mass spectroscopy. The most likely structure suggested for the ruthenium(II species is mer-[Ru(N2Me43(acacH]. Mercury poisoning experiment indicates that the catalytic dehydrogenation of dimethylamine-borane is homogeneous catalysis. The kinetics of the catalytic dehydrogenation of dimethylamine borane starting with Ru(acac3 were studied depending on the catalyst concentration, substrate concentration and temperature. The hydrogen generation was found to be first-order with respect to catalyst concentration and zero-order regarding the substrate concentration. Evaluation of the kinetic data provides the activation parameters for the dehydrogenation reaction: the activation energy Ea = 85 ± 2 kJ·mol−1, the enthalpy of activation ∆H# = 82 ± 2 kJ·mol−1 and the entropy of activation; ∆S# = −85 ± 5 J·mol−1·K−1. The ruthenium(II catalyst formed from the reduction of ruthenium(III acetylacetonate provides 1700 turnovers over 100 hours in hydrogen generation from the dehydrogenation of dimethylamine borane before deactivation at 60 °C.

  11. Ruthenium isotopic evidence for an inner Solar System origin of the late veneer.

    Science.gov (United States)

    Fischer-Gödde, Mario; Kleine, Thorsten

    2017-01-25

    The excess of highly siderophile elements in the Earth's mantle is thought to reflect the addition of primitive meteoritic material after core formation ceased. This 'late veneer' either comprises material remaining in the terrestrial planet region after the main stages of the Earth's accretion, or derives from more distant asteroidal or cometary sources. Distinguishing between these disparate origins is important because a late veneer consisting of carbonaceous chondrite-like asteroids or comets could be the principal source of the Earth's volatiles and water. Until now, however, a 'genetic' link between the late veneer and such volatile-rich materials has not been established or ruled out. Such genetic links can be determined using ruthenium (Ru) isotopes, because the Ru in the Earth's mantle predominantly derives from the late veneer, and because meteorites exhibit Ru isotope variations arising from the heterogeneous distribution of stellar-derived dust. Although Ru isotopic data and the correlation of Ru and molybdenum (Mo) isotope anomalies in meteorites were previously used to argue that the late veneer derives from the same type of inner Solar System material as do Earth's main building blocks, the Ru isotopic composition of carbonaceous chondrites has not been determined sufficiently well to rule them out as a source of the late veneer. Here we show that all chondrites, including carbonaceous chondrites, have Ru isotopic compositions distinct from that of the Earth's mantle. The Ru isotope anomalies increase from enstatite to ordinary to carbonaceous chondrites, demonstrating that material formed at greater heliocentric distance contains larger Ru isotope anomalies. Therefore, these data refute an outer Solar System origin for the late veneer and imply that the late veneer was not the primary source of volatiles and water on the Earth.

  12. Ruthenium isotopic evidence for an inner Solar System origin of the late veneer

    Science.gov (United States)

    Fischer-Gödde, Mario; Kleine, Thorsten

    2017-01-01

    The excess of highly siderophile elements in the Earth’s mantle is thought to reflect the addition of primitive meteoritic material after core formation ceased. This ‘late veneer’ either comprises material remaining in the terrestrial planet region after the main stages of the Earth’s accretion, or derives from more distant asteroidal or cometary sources. Distinguishing between these disparate origins is important because a late veneer consisting of carbonaceous chondrite-like asteroids or comets could be the principal source of the Earth’s volatiles and water. Until now, however, a ‘genetic’ link between the late veneer and such volatile-rich materials has not been established or ruled out. Such genetic links can be determined using ruthenium (Ru) isotopes, because the Ru in the Earth’s mantle predominantly derives from the late veneer, and because meteorites exhibit Ru isotope variations arising from the heterogeneous distribution of stellar-derived dust. Although Ru isotopic data and the correlation of Ru and molybdenum (Mo) isotope anomalies in meteorites were previously used to argue that the late veneer derives from the same type of inner Solar System material as do Earth’s main building blocks, the Ru isotopic composition of carbonaceous chondrites has not been determined sufficiently well to rule them out as a source of the late veneer. Here we show that all chondrites, including carbonaceous chondrites, have Ru isotopic compositions distinct from that of the Earth’s mantle. The Ru isotope anomalies increase from enstatite to ordinary to carbonaceous chondrites, demonstrating that material formed at greater heliocentric distance contains larger Ru isotope anomalies. Therefore, these data refute an outer Solar System origin for the late veneer and imply that the late veneer was not the primary source of volatiles and water on the Earth.

  13. Session: Hard Rock Penetration

    Energy Technology Data Exchange (ETDEWEB)

    Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

  14. Hard-hat day

    CERN Multimedia

    2003-01-01

    CERN will be organizing a special information day on Friday, 27th June, designed to promote the wearing of hard hats and ensure that they are worn correctly. A new prevention campaign will also be launched.The event will take place in the hall of the Main Building from 11.30 a.m. to 2.00 p.m., when you will be able to come and try on various models of hard hat, including some of the very latest innovative designs, ask questions and pass on any comments and suggestions.

  15. Improved ruthenium catalysts for Z-selective olefin metathesis.

    Science.gov (United States)

    Keitz, Benjamin K; Endo, Koji; Patel, Paresma R; Herbert, Myles B; Grubbs, Robert H

    2012-01-11

    Several new C-H-activated ruthenium catalysts for Z-selective olefin metathesis have been synthesized. Both the carboxylate ligand and the aryl group of the N-heterocyclic carbene have been altered and the resulting catalysts evaluated using a range of metathesis reactions. Substitution of bidentate with monodentate X-type ligands led to a severe attenuation of metathesis activity and selectivity, while minor differences were observed between bidentate ligands within the same family (e.g., carboxylates). The use of nitrato-type ligands in place of carboxylates afforded a significant improvement in metathesis activity and selectivity. With these catalysts, turnover numbers approaching 1000 were possible for a variety of cross-metathesis reactions, including the synthesis of industrially relevant products. © 2011 American Chemical Society

  16. Interaction of nitric oxide wth the (1010) face of ruthenium

    Energy Technology Data Exchange (ETDEWEB)

    Orent, T.W.

    1977-02-01

    The low-energy electron diffraction (LEED) technique was used to probe the atomic geometry of the surfaces that resulted from the steady-state interaction of nitric oxide with Ru(10 anti 10) as a function of temperature and pressure. Auger electron spectroscopy (AES) was used to identify the atomic species present on these surfaces. Results were obtained at reactant partial pressures in the range from 10/sup -9/ to 10/sup -6/ torr and substrate temperatures from -25 to 950/sup 0/C. The interaction of molecular oxygen with the surface was also examined. A qualitative correlation exists between the observed structures and the reported enhancement in the catalytic activity of supported ruthenium after the catalyst had been pretreated with oxygen. (JRD)

  17. Phosphine-Free EWG-Activated Ruthenium Olefin Metathesis Catalysts

    Science.gov (United States)

    Grela, Karol; Szadkowska, Anna; Michrowska, Anna; Bieniek, Michal; Sashuk, Volodymyr

    Hoveyda-Grubbs catalyst has been successfully fine-tuned by us in order to increase its activity and applicability by the introduction of electron-withdrawing groups (EWGs) to diminish donor properties of the oxygen atom. As a result, the stable and easily accessible nitro-substituted Hoveyda-Grubbs catalyst has found a number of successful applications in various research and industrial laboratories. Some other EWG-activated Hoveyda-type catalysts are commercially available. The results described herewith demonstrate that the activity of ruthenium (Ru) metathesis catalysts can be enhanced by introduction of EWGs without detriment to catalysts stability. Equally noteworthy is the observation that different Ru catalysts turned out to be optimal for different applications. This shows that no single catalyst outperforms all others in all possible applications.

  18. Ruthenium speciation in model nuclear fuel process solutions

    Energy Technology Data Exchange (ETDEWEB)

    Koster, Anne L.; May, Iain; Sharrad, Clint A.; Wright, Des; Owens, Ivan F.; Charnock, John M.; Hennig, Christoph

    2004-07-01

    Ru speciation is being investigated systematically from models of high level waste solutions right through to the calcination process and the vitrified glass product. The characterisation of these species is complicated due to the fact that a wide range of ruthenium nitrosyl/nitrite/nitrate complexes can be present in nitric acid waste solutions. The general formula for these complexes is RuNO(NO{sub 3}){sub x}(NO{sub 2}){sub y}(OH){sub z}(H{sub 2}O){sub 5-x-y-z}{sup +3-x-y-z}. A range of different techniques has been used for the characterisation of these species in solution, including electron absorption spectroscopy, vibrational spectroscopy, multi-nuclear magnetic resonance spectroscopy and X-ray absorption spectroscopy. (authors)

  19. Bulky N-Phosphino-Functionalized N-Heterocyclic Carbene Ligands: Synthesis, Ruthenium Coordination Chemistry, and Ruthenium Alkylidene Complexes for Olefin Metathesis.

    Science.gov (United States)

    Brown, Christopher C; Rominger, Frank; Limbach, Michael; Hofmann, Peter

    2015-11-02

    Ruthenium chemistry and applications in catalytic olefin metathesis based on N-phosphino-functionalized N-heterocyclic carbene ligands (NHCPs) are presented. Alkyl NHCP Ru coordination chemistry is described, and access to several potential synthetic precursors for ruthenium alkylidene complexes is outlined, incorporating both trimethylsilyl and phenyl alkylidenes. The Ru alkylidene complexes are evaluated as potential olefin metathesis catalysts and were shown to behave in a latent fashion. They displayed catalytic activity at elevated temperatures for both ring closing metathesis and ring opening metathesis polymerization.

  20. Mono and dinuclear arene ruthenium(II) triazoles by 1,3-dipolar cycloadditions to a coordinated azide in ruthenium(II) compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Svitlyk, V.; Mozharivskyj, Y.

    reaction of [(η 6 - C 6 Me 6 )Ru(L 2 )Cl] with sodium azide. Notably, as mentioned earlier, a direct reaction of [(η 6 -C 6 Me 6 ) Ru(L 1 )Cl] (1) with NaN 3 in ethanol yielded tetra azido compound of formulation [{(η 6 - C 6 Me 6 )Ru(N 3 )(N 3 )} 2... sodium azide. As a part of our study on arene ruthenium (II) azide compounds, 11 herein, we would like to report, the synthesis of (η 6 -C 6 Me 6 ) ruthenium (II) azido compound 2 and the subsequent 1,3-dipolar cycloaddition reaction of 1 and 2...

  1. Hardness and excitation energy

    Indian Academy of Sciences (India)

    It is shown that the first excitation energy can be given by the Kohn-Sham hardness (i.e. the energy difference of the ground-state lowest unoccupied and highest occupied levels) plus an extra term coming from the partial derivative of the ensemble exchange-correlation energy with respect to the weighting factor in the ...

  2. Hard Probes at ATLAS

    CERN Document Server

    Citron, Z; The ATLAS collaboration

    2014-01-01

    The ATLAS collaboration has measured several hard probe observables in Pb+Pb and p+Pb collisions at the LHC. These measurements include jets which show modification in the hot dense medium of heavy ion collisions as well as color neutral electro-weak bosons. Together, they elucidate the nature of heavy ion collisions.

  3. Hardness of metallic crystals

    Indian Academy of Sciences (India)

    Administrator

    where H is the hardness, k the coefficient, G the shear modulus, ν the Poisson's ratio, η a function of the radius of an atom (r) and the electron density at the atom interface (n). The formula will not only be used to testify the critical grain size with stable dislocations, but also play an important role in the understanding of ...

  4. Running in Hard Times

    Science.gov (United States)

    Berry, John N., III

    2009-01-01

    Roberta Stevens and Kent Oliver are campaigning hard for the presidency of the American Library Association (ALA). Stevens is outreach projects and partnerships officer at the Library of Congress. Oliver is executive director of the Stark County District Library in Canton, Ohio. They have debated, discussed, and posted web sites, Facebook pages,…

  5. Hard and Soft Governance

    DEFF Research Database (Denmark)

    Moos, Lejf

    2009-01-01

    The governance and leadership at transnational, national and school level seem to be converging into a number of isomorphic forms as we see a tendency towards substituting 'hard' forms of governance, that are legally binding, with 'soft' forms based on persuasion and advice. This article analyses...

  6. Hardness and excitation energy

    Indian Academy of Sciences (India)

    Unknown

    form a new species leading to a single electronegativity or chemical potential (the same way as in ordinary thermodynamics). The hardness η of an electronic system is ..... Technological Innovation Foundation and the Minis- try of Science and Technology. This work was also supported by the grant OTKA No. T042505.

  7. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  8. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. R A PAWAR. Articles written in Bulletin of Materials Science. Volume 40 Issue 7 December 2017 pp 1335-1345. Chemical synthesis and characterization of nano-sized rare-earth ruthenium pyrochlore compounds Ln 2 Ru 2 O 7 (Ln = rare earth) · R A PAWAR A K NIKUMBH D S ...

  9. ``Greener Shade of Ruthenium'': New Concepts of Activation, Immobilization, and Recovery of Ruthenium Catalysts For Green Olefin Metathesis

    Science.gov (United States)

    Michrowska, Anna; Gulajski, Lukasz; Grela, Karol

    The results described herewith demonstrate that the activity of ruthenium (Ru) metathesis catalysts can be enhanced by introduction of electron-withdrawing groups (EWGs) without detriment to catalysts stability. This principle can be used not only to increase the catalyst activity, but also to alter its physical-chemical properties, such as solubility in given medium or affinity to silica gel. An example of novel immobilisation strategy, based on this concept is presented. The ammonium-tagged Hoveyda-type catalysts can be successfully applied in aqueous media as well as in ionic liquids (IL). Substitution of a benzylidene fragment can be used not only to immobilize the organometallic complex in such media, but also to increase its catalytic activity by electronic activation. The high stability and good application profiles of such modified catalysts in conjunction with their facile removal from organic products can be expected to offer new opportunities in green applications of olefin metathesis.

  10. Rad Hard Active Media For Calorimeters

    CERN Document Server

    Norbeck, E; Möller, A; Onel, Y

    2006-01-01

    Zero-degree calorimeters have limited space and extreme levels of radiation. A simple, low cost, radiation hard design uses tungstenmetal as the absorber and a suitable liquid as the ˇCerenkov radiator. In other applications a PPAC (Parallel Plate Avalanche Counter) operatingwith a suitable atmosphericpressure gas is an attractive active material for a calorimeter. It can be made radiation hard and has sufficient gain in the gas that no electronic components are needed near the detector. It works well even with the highest concentration of shower particles. For this pressure range, R134A (used in auto air conditioners) has many desirable features.

  11. Radiation hardness of semiconductor detectors for high-energy physics

    Energy Technology Data Exchange (ETDEWEB)

    Khludkov, S.S.; Stepanov, V.E.; Tolbanov, O.P. [Tomskij Gosudarstvennyj Univ., Tomsk (Russian Federation). Sibirskij Fiziko-Tekhnicheskij Inst.

    1996-06-14

    The concept of radiation hardness of semiconductor materials in terms of local charge neutrality is proposed. Deep centres are invoked to play the basic role in the attainment of radiation hardness by high-resistivity semiconductor charged particle detectors exposed to neutron irradiation. (author).

  12. Hard times, hard choices: founding bioethics today.

    Science.gov (United States)

    Gracia, Diego

    1995-07-01

    The discussions of these past twenty years have significantly improved our knowledge about the foundation of bioethics and the meaning of the four bioethical principles with concern to at least three different points: that they are organised hierarchically, and therefore not "prima facie" of the same level; that they have exceptions, and consequently lack of absolute character; and that they are neither strictly deontological nor purely teleological. The only absolute principle of moral life can be the abstract and unconcrete respect of human beings. But when determining the material content of this respect, principles become contingent and relative. Therefore, moral reasoning must have necessarily no less than three moments, one absolute but merely formal, namely respect for all human beings, and the other two relative and material. The first material moment is comprised of the four bioethical principles, divided into two levels, one private, including the principles of autonomy and beneficence, and the other one public, including those of nonmaleficence and justice. The second material moment deals with specific cases, and requires analysis of their context, including their circumstances and consequences. Only when following these steps, and therefore balancing principlism and contextualism, can moral reasoning be correct and complete.

  13. Hard Probes at RHIC

    Directory of Open Access Journals (Sweden)

    Bielčíková Jana

    2014-04-01

    Full Text Available Measurements of jets and heavy flavour, the so called hard probes, play a crucial role in understanding properties of hot and dense nuclear matter created in high energy heavy-ion collisions. The measurements at the Relativistic Heavy Ion Collider (RHIC showed that in central Au+Au collisons at RHIC energy ( √sNN = 200 GeV the nuclear matter created has properties close to those of perfect liquid, manifests partonic degrees of freedom and is opaque to hard probes. In order to draw quantitative conclusions on properties of this hot and dense nuclear matter reference measurements in proton-proton collisions and d+Au collisions are essential to estimate cold nuclear matter effects. In this proceedings a review of recent results on hard probes measurements in p+p, d+Au and A+A collisions as well as of beam energy dependence of jet quenching from STAR and PHENIX experiments at RHIC is presented.

  14. Electrochemical properties of the hexacyanoferrate(II)–ruthenium(III) complex immobilized on silica gel surface chemically modified with zirconium(IV) oxide

    Energy Technology Data Exchange (ETDEWEB)

    Panice, Lucimara B.; Oliveira, Elisangela A. de; Filho, Ricardo A.D. Molin; Oliveira, Daniela P. de [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Lazarin, Angélica M., E-mail: amlazarin2@uem.br [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Andreotti, Elza I.S.; Sernaglia, Rosana L. [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Gushikem, Yoshitaka [Instituto de Química, Universidade Estadual de Campinas, Caixa Postal 6154, 13084-971 Campinas, São Paulo (Brazil)

    2014-10-15

    Highlights: • The cyano-bridged mixed valence ruthenium composite material was synthesized. • This newly synthesized compound was incorporated into a carbon paste electrode. • The electrode did not show significant changes in response after six months of use. • The modified electrode is very stable and reproducible. • The electrode sensor was successfully applied for ascorbic acid determination. - Abstract: The chemically modified silica gel with zirconium(IV) oxide was used to immobilize the [Fe(CN){sub 6}]{sup 4−} complex ion initially. The reaction of this material with [Ru(edta)H{sub 2}O]{sup −} complex ion formed the immobilized cyano-bridged mixed valence ruthenium complex, (≡Zr){sub 5}[(edta)RuNCFe(CN){sub 5}]. This material was incorporated into a carbon paste electrode and, its electrochemical properties were investigated. However, for an ascorbic acid solution, an enhancement of the anodic peak current was detected due to electrocatalytic oxidation. The electrode presented the same response for at least 150 successive measurements, with a good repeatability. The modified electrode is very stable and reproducible. The sensor was applied for ascorbic acid determination in pharmaceutical preparation with success.

  15. Syntheses and Characterization of Ruthenium(II) Tetrakis(pyridine)complexes: An Advanced Coordination Chemistry Experiment or Mini-Project

    Science.gov (United States)

    Coe, Benjamin J.

    2004-01-01

    An experiment for third-year undergraduate a student is designed which provides synthetic experience and qualitative interpretation of the spectroscopic properties of the ruthenium complexes. It involves the syntheses and characterization of several coordination complexes of ruthenium, the element found directly beneath iron in the middle of the…

  16. A facile one-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica: Aqueous hydration of nitriles to amides

    Science.gov (United States)

    One-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica is described which involve the in situ generation of magnetic silica (Fe3O4@ SiO2) and ruthenium hydroxide immobilization; the hydration of nitriles occurs in high yield and excellent selectivity using this...

  17. Dehydrogenative Coupling of Primary Alcohols To Form Esters Catalyzed by a Ruthenium N-Heterocyclic Carbene Complex

    DEFF Research Database (Denmark)

    Sølvhøj, Amanda Birgitte; Madsen, Robert

    2011-01-01

    The ruthenium complex [RuCl2(IiPr)(p-cymene)] catalyzes the direct condensation of primary alcohols into esters and lactones with the release of hydrogen gas. The reaction is most effective with linear aliphatic alcohols and 1,4-diols and is believed to proceed with a ruthenium dihydride as the c...

  18. Mesoporous Ruthenium/Ruthenium Oxide Thin Films: Active Electrocatalysts for the Oxygen Evolution Reaction

    DEFF Research Database (Denmark)

    Kibsgaard, Jakob; Hellstern, Thomas R.; Choi, Shin-Jung

    2017-01-01

    We report the first synthesis of a fully contiguous large area supported thin film of highly ordered mesoporous Ru and RuO2 and investigate the electrocatalytic properties towards the oxygen evolution reaction (OER). We find that the nanoscale porous network of these catalysts provides significan...... enhancements in geometric OER activity without any loss in specific activity. This work demonstrates a strategy for engineering materials at the nanoscale that can simultaneously decrease precious metal loading and increase electrode activity....

  19. A kinetic study on the adsorption and reaction of hydrogen over silica-supported ruthenium and silver-ruthenium catalysts during the hydrogenation of carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    VanderWiel, David P. [Iowa State Univ., Ames, IA (United States)

    1999-02-12

    Although the catalytic hydrogenation of carbon monoxide has been a subject of considerable investigation for many years, its increasing economical attractiveness as an industrial source of hydrocarbons has recently led to a search for more active and selective catalysts. A fundamental problem in the development of such catalysts is an incomplete knowledge of the operative surface processes, due in large part to the inability to accurately measure surface concentrations of reactant species during reaction. Specifically, the concentration of surface hydrogen proves difficult to estimate using normally revealing techniques such as transient isotopic exchange due to kinetic isotope effects. Knowledge of such concentrations is essential to the determination of the mechanisms of adsorption and reaction, since many kinetic parameters are concentration dependent. It is the aim of this research to investigate the mechanism and kinetics of the adsorption and reaction of hydrogen on silica-supported ruthenium and silver-ruthenium catalysts during the hydrogenation of carbon monoxide. By preadsorbing carbon monoxide onto the surface of ruthenium and silver-ruthenium catalysts, the kinetics of hydrogen adsorption and reaction can be monitored upon exposure of this surface to ambient hydrogen gas. This is accomplished by conducting identical experiments on two separate systems. First, the formation of methane is monitored using mass spectroscopy, and specific reaction rates and apparent activation energies are measured. Next, in situ 1H-NMR is used to monitor the amount of hydrogen present on the catalyst surface during adsorption and reaction. The results for these two sets of experiments are then combined to show a correlation between the rate of reaction and the surface hydrogen concentration. Finally, transition state theory is applied to this system and is used to explain the observed change in the apparent activation energy. The structure sensitivity of hydrogen

  20. Mitigation of strontium and ruthenium release in the CANDU primary heat transport system

    Energy Technology Data Exchange (ETDEWEB)

    McFarlane, J

    1998-03-01

    In certain severe accident scenarios, low-volatility fission products can appear to contribute significantly to dose, if treated with undue conservatism. Hence a survey was performed, to see if factors that may mitigate release of strontium and ruthenium could be incorporated into safety analyses, to cover parameters such as location in the fuel matrix under normal operating conditions, release from fuel, transport and deposition in the primary heat transport system and chemistry. In addition chemical equilibrium calculations were performed to investigate the volatility of strontium and ruthenium in the presence of uranium and important fission products. Strontium is very soluble in the U0{sub 2} fuel, up to 12 atom %, and hence release is improbable, particularly under oxidizing conditions until volatilization of the fuel matrix itself occurs. Ruthenium, however, can be released at low temperatures, but only under oxidizing conditions. These may occur during a fuel-handling accident or as a result of an end-fitting failure. Under these conditions, the primary heat transport system cannot be credited for retention. The volatile form of ruthenium, RuO{sub 4}(g), is thermally unstable above 381 K and decomposes to RuO{sub 2}(s) and O{sub 2}(g) upon contact with surfaces, a factor that is likely to minimize the release of ruthenium into the environment. (author)

  1. One-pot hydrothermal synthesis of ruthenium oxide nanodots on reduced graphene oxide sheets for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yao [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Graduate University of Chinese Academy Sciences, Beijing 100049 (China); Zhang Xiong [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Zhang Dacheng [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Graduate University of Chinese Academy Sciences, Beijing 100049 (China); Ma Yanwei, E-mail: ywma@mail.iee.ac.cn [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

    2012-01-15

    Highlights: > Graphite oxide instead of graphene as precursor has been used to synthesize reduced graphene oxide/ruthenium oxide composites by a hydrothermal treatment. > Using NaOH solution to adjust pH of GO colloids leads to homogeneous ruthenium oxide deposited on reduced graphene oxide sheets. > A maximum capacitance of 471 F g{sup -1} is obtained at 0.5 A g{sup -1} for the composites when loading 40% of RuO{sub 2} and its life retention reaches 92% after 3000 cycles. - Abstract: Ruthenium oxide nanodots have been deposited on reduced graphene oxide (RGO) sheets homogeneously by hydrothermal and annealing methods. Adding NaOH solution in GO colloids prevents the restack and agglomeration of GO sheets when mixed with ruthenium chloride solution. Local crystallization of RuO{sub 2} in the composites is revealed by X-ray diffraction and transmission electron microscopy. The element mapping image demonstrates the uniform distribution of Ru on RGO sheets. Unlike the pure crystalline RuO{sub 2} exhibiting poor electrochemical performance, the composites present superior capacitive properties. The hydrothermal time is optimized and a maximum of 471 F g{sup -1} is measured in the composites at 0.5 A g{sup -1} when loaded with 45 wt% of RuO{sub 2}. After 3000 cycles, its specific capacitance remains 92% of the maximum capacitance. Our results suggest potential application of the reduced graphene oxide/ruthenium oxide composites to supercapacitors.

  2. Does the imaging method have an influence on the measured tumor height in ruthenium plaque therapy of uveal melanoma?

    Energy Technology Data Exchange (ETDEWEB)

    Schueller, P.; Dogan, A.; Micke, O.; Willich, N. [Dept. of Radiotherapy and Radiation Oncology, Univ. of Muenster (Germany); Panke, J.E. [Dept. of Radiotherapy and Nuclear Medicine, Univ. of Luebeck (Germany)

    2005-05-01

    Background and purpose: for ruthenium plaque therapy of uveal melanoma the precise knowledge of the tumor height is necessary. The purpose of this analysis is to examine systematic differences between ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) measurements of tumor height in uveal melanoma. Material and methods: from 1993 to 2000, 208 patients with uveal melanoma were treated with ruthenium therapy. US was done in 190/208 patients, CT in 147/208 patients, and MRI in 81/208 patients. The measurements from the imaging modalities were compared to each other. Separate comparisons were carried out for tumor size and localization and between two-dimensional (2-D) and three-dimensional (3-D) measurements in reconstructed planes. Results: in direct comparison, CT measurements (median: 4.5 mm; range: 1.6-10.5 mm) were nearly identical to MRI measurements (median: 4.5 mm; range: 2.0-11.4 mm), while US yielded the highest values (median: 5.2 mm; range: 2.5-13.4 mm). Linear regression yielded the following values: CT versus US (R{sup 2} = 0.88, correlation coefficient = 1.04), MRI versus US (R{sup 2} = 0.79, correlation coefficient = 0.92), MRI versus CT (R{sup 2} = 0.84, correlation coefficient = 0.90), and ''2-D'' versus reconstructed ''3-D'' (R{sup 2} = 0.93, correlation coefficient = 0.98). Conclusion: differences between the measurements from all three modalities were generally acceptable, except for small tumors ({<=} 4 mm; limited spatial resolution of CT/MRI) and temporal or peripheral lesions (angular distortion in US). In special anatomic situations, CT/MRI measurements can also result in distortions. ''3-D'' measurements can sometimes help in these situations. (orig.)

  3. Synthesis, Structure, and Properties of Refractory Hard-Metal Borides

    Science.gov (United States)

    Lech, Andrew Thomas

    As the limits of what can be achieved with conventional hard compounds, such as tungsten carbide, are nearing reach, super-hard materials are an area of increasing industrial interest. The refractory hard metal borides, such as ReB2 and WB4, offer an increasingly attractive alternative to diamond and cubic boron nitride as a next-generation tool material. In this Thesis, a thorough discussion is made of the progress achieved by our laboratory towards understanding the synthesis, structure, and properties of these extremely hard compounds. Particular emphasis is placed on structural manipulation, solid solution formation, and the unique crystallographic manifestations of what might also be called "super-hard metals".

  4. Ruthenium(II) Complex Based Photodiode for Organic Electronic Applications

    Science.gov (United States)

    Tataroglu, A.; Ocaya, R.; Dere, A.; Dayan, O.; Serbetci, Z.; Al-Sehemi, Abdullah G.; Soylu, M.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.

    2018-01-01

    In this study, the electrical and photoresponse properties of a photovoltaic device with Ruthenium(II) complex interfacial thin film were investigated. Heteroleptic Ru(II) complex including bidentate and tridentate ligands thin film was coated on n-Si substrate by the spin coating technique. From current-voltage ( I- V) measurements of an Au/Ru(II)/n-Si photodiode, it is observed that the reverse bias current under light is higher than that of the current in the dark. This indicates that the photodiode exhibits a photoconducting characteristic. The transient measurements such as photocurrent, photocapacitance and photoconductance were performed under various illumination conditions. These measurements indicate that the photodiode has a high photoresponsivity. The electrical parameters such as barrier height (Φb), ideality factor ( n) and series resistance ( R s) of the photodiode were determined from the analysis of I- V characteristics. Moreover, the capacitance/conductance-voltage characteristics of the photodiode highly depend on both voltage and frequency. Results show that the heterojunction can be used for various optoelectronic applications.

  5. Coordinatively unsaturated ruthenium complexes as efficient alkyneazide cycloaddition catalysts

    KAUST Repository

    Lamberti, Marina

    2012-01-23

    The performance of 16-electron ruthenium complexes with the general formula Cp*Ru(L)X (in which L = phosphine or N-heterocyclic carbene ligand; X = Cl or OCH2CF3) was explored in azidealkyne cycloaddition reactions that afford the 1,2,3- triazole products. The scope of the Cp*Ru(PiPr 3)Cl precatalyst was investigated for terminal alkynes leading to new 1,5-disubstituted 1,2,3-triazoles in high yields. Mechanistic studies were conducted and revealed a number of proposed intermediates. Cp*Ru- (PiPr3)(2-HCCPh)Cl was observed and characterized by 1H, 13C, and 31P NMR at temperatures between 273 and 213 K. A rare example of N,N-κ2-phosphazide complex, Cp*Ru(κ2- iPr3PN3Bn)Cl, was fully characterized, and a single-crystal X-ray diffraction structure was obtained. DFT calculations describe a complete map of the catalytic reactivity with phenylacetylene and/or benzylazide. © 2012 American Chemical Society.

  6. Homobimetallic Ruthenium-N-Heterocyclic Carbene Complexes For Olefin Metathesis

    Science.gov (United States)

    Sauvage, Xavier; Demonceau, Albert; Delaude, Lionel

    In this chapter, the synthesis and catalytic activity towards olefin metathesis of homobimetallic ruthenium (Ru)-alkylidene, -cyclodiene or -arene complexes bearing phosphine or N-heterocyclic carbene (NHC) ligands are reviewed. Emphasis is placed on the last category of bimetallic compounds. Three representatives of this new type of molecular scaffold were investigated. Thus, [(p-cymene)Ru(m-Cl)3RuCl (h2-C2H4)(L)] complexes with L = PCy3 (15a), IMes (16a), or IMesCl2 (16b) were prepared. They served as catalyst precursors for cross-metathesis (CM) of various styrene derivatives. These experiments revealed the outstanding aptitude of complex 16a (and to a lesser extent of 16b) to catalyze olefin metathesis reactions. Contrary to monometallic Ru-arene complexes of the [RuCl2(p-cymene)(L)] type, the new homobimetallic species did not require the addition of a diazo compound nor visible light illumination to initiate the ring-opening metathesis of norbornene or cyclooctene. When diethyl 2,2-diallylmalonate and N,N-diallyltosylamide were exposed to 16a,b, a mixture of cycloisomerization and ring-closing metathesis (RCM) products was obtained in a nonselective way. Addition of phenylacetylene enhanced the metathetical activity while completely repressing the cycloisomerization process.

  7. Ruthenium olefin metathesis catalysts featuring unsymmetrical N-heterocyclic carbenes.

    Science.gov (United States)

    Paradiso, Veronica; Bertolasi, Valerio; Costabile, Chiara; Grisi, Fabia

    2016-01-14

    New ruthenium Grubbs' and Hoveyda-Grubbs' second generation catalysts bearing N-alkyl/N-isopropylphenyl N-heterocyclic carbene (NHC) ligands with syn or anti backbone configuration were obtained and compared in model olefin metathesis reactions. Different catalytic efficiencies were observed depending on the size of the N-alkyl group (methyl or cyclohexyl) and on the backbone configuration. The presence of an N-cyclohexyl substituent determined the most significant reactivity differences between catalysts with syn or anti phenyl groups on the backbone. In particular, anti catalysts proved highly efficient, especially in the ring-closing metathesis (RCM) of encumbered diolefins, while syn catalysts showed low efficiency in the RCM of less hindered diolefins. This peculiar behavior, rationalized through DFT studies, was found to be related to the high propensity of these catalysts to give nonproductive metathesis events. Enantiopure anti catalysts were also tested in asymmetric metathesis reactions, where moderate enantioselectivities were observed. The steric and electronic properties of unsymmetrical NHCs with the N-cyclohexyl group were then evaluated using the corresponding rhodium complexes. While steric factors proved unimportant for both syn and anti NHCs, a major electron-donating character was found for the unsymmetrical NHC with anti phenyl substituents on the backbone.

  8. The synthesis and the reactivity of arene ruthenium oxalato complexes

    Directory of Open Access Journals (Sweden)

    Cheikh Mbacké Ndiaye

    2008-08-01

    Full Text Available This article outlines the reactions of the well known [RuCl(η6-p-cymene]2(μ-η4-C2O4 and [RuCl(η6-p-cymene(η2-dppm][PF6] ruthenium complexes with C2O4 (Me4N 2 in the mol ratios 1:1 and 2:1. While the 2:1 ratio reaction led to the sole and expected binuclear product {[Ru(η6-p-cymene(η2-dppm]2(μ-η2-C2O4}[PF6]2, the reaction also afforded the unexpected mononuclear complex [RuCl(η2-C2O4(η6-p-cymene][Me4N]. This can also be obtained in improved yield by reacting [RuCl2(p-cymene] 2 with C2O4[Me4N] 2 in a 1:1 mol ratio. Surprisingly, when [RuCl(η6-p-cymene]2(μ-η4-C2O4 was reacted with an equimolar amount of the ligand dppm, the expected complex {[Ru(η6-p-cymene]2(μ-η4-C2O4(μ-dppm}[PF6]2 was accompanied by [RuCl(η6-p-cymene(η2-dppm][PF6] in an inseparable solid mixture.

  9. Experience with Ruthenium /sup 106/-treatment of uveal malignant melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Laatikainen, L.; Tarkkanen, A.

    1987-01-01

    In 1981-1986, 25 eyes with malignant melanoma of the uvea were treated with beta irradiation using ruthenium/sup 106/ plaques. In 21 cases the tumour originated in the choriod, in 4 cases in the ciliary body. In 12 eyes it was within 3 mm from the optic disc or the fovea, and the mean height (+-SEM) was 5.2+-0.4 mm. Three eyes received two sets of irradiation with 1.1 - 1.7 years' interval. After a mean followup of 1.6 years (range 0,5 - 5.6) the tumour had decreased in size in 12, was unchanged in 6, and had progressed in 7 eyes, 4 of the latter were enucleated. In 3 patients metastases were diagnosed (2.0 -2.9 years after irradiation), and 1 patient has died (3.3 years after the first irradiation). Twelve eyes have retained useful vision (0.05 or better), but in some of them a tendency to deterioration was observed 3-5 years after treatment due to radiation maculopathy. Other causes of visual loss were the centrally located tumour itself, exudative detachment of the retina, and persistent vitreous haemorrhage.

  10. Coordination of dibensothiophenes and corannulenes to organometallic ruthenium (II) fragments

    Energy Technology Data Exchange (ETDEWEB)

    Vecchi, Paul Anthony [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    This dissertation contains five papers in the format required for journal publication which describe (in part) my research accomplishments as a graduate student at Iowa State University. This work can be broadly categorized as the binding of weakly-coordinating ligands to cationic organometallic ruthenium fragments, and consists of two main areas of study. Chapters 2-4 are investigations into factors that influence the binding of dibenzothiophenes to [Cp'Ru(CO)2(+ fragments, where Cp' = η5-C5H5 (Cp) and η5-C5Me5 (Cp*). Chapters 5 and 6 present the synthesis and structural characterization of complexes containing corannulene buckybowls that are η6-coordinated to [Cp*Ru(+ fragments. The first chapter contains a brief description of the difficulty in lowering sulfur levels in diesel fuel along with a review of corannulene derivatives and their metal complexes. After the final paper is a short summary of the work herein (Chapter 7). Each chapter is independent, and all equations, schemes, figures, tables, references, and appendices in this dissertation pertain only to the chapter in which they appear.

  11. Ruthenium(II) Complex Based Photodiode for Organic Electronic Applications

    Science.gov (United States)

    Tataroglu, A.; Ocaya, R.; Dere, A.; Dayan, O.; Serbetci, Z.; Al-Sehemi, Abdullah G.; Soylu, M.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.

    2017-10-01

    In this study, the electrical and photoresponse properties of a photovoltaic device with Ruthenium(II) complex interfacial thin film were investigated. Heteroleptic Ru(II) complex including bidentate and tridentate ligands thin film was coated on n-Si substrate by the spin coating technique. From current-voltage (I-V) measurements of an Au/Ru(II)/n-Si photodiode, it is observed that the reverse bias current under light is higher than that of the current in the dark. This indicates that the photodiode exhibits a photoconducting characteristic. The transient measurements such as photocurrent, photocapacitance and photoconductance were performed under various illumination conditions. These measurements indicate that the photodiode has a high photoresponsivity. The electrical parameters such as barrier height (Φb), ideality factor (n) and series resistance (R s) of the photodiode were determined from the analysis of I-V characteristics. Moreover, the capacitance/conductance-voltage characteristics of the photodiode highly depend on both voltage and frequency. Results show that the heterojunction can be used for various optoelectronic applications.

  12. Ruthenium(II) complexes containing quinone based ligands: Synthesis, characterization, catalytic applications and DNA interaction

    Science.gov (United States)

    Anitha, P.; Manikandan, R.; Endo, A.; Hashimoto, T.; Viswanathamurthi, P.

    2012-12-01

    1,2-Naphthaquinone reacts with amines such as semicarbazide, isonicotinylhydrazide and thiosemicarbazide in high yield procedure with the formation of tridentate ligands HLn (n = 1-3). By reaction of ruthenium(II) starting complexes and quinone based ligands HLn (n = 1-3), a series of ruthenium complexes were synthesized and characterized by elemental and spectroscopic methods (FT-IR, electronic, 1H, 13C, 31P NMR and ESI-MS). The ligands were coordinated to ruthenium through quinone oxygen, imine nitrogen and enolate oxygen/thiolato sulfur. On the basis of spectral studies an octahedral geometry may be assigned for all the complexes. Further, the catalytic oxidation of primary, secondary alcohol and transfer hydrogenation of ketone was carried out. The DNA cleavage efficiency of new complexes has also been tested.

  13. meta-C-H Bromination on Purine Bases by Heterogeneous Ruthenium Catalysis.

    Science.gov (United States)

    Warratz, Svenja; Burns, David J; Zhu, Cuiju; Korvorapun, Korkit; Rogge, Torben; Scholz, Julius; Jooss, Christian; Gelman, Dmitri; Ackermann, Lutz

    2017-02-01

    Methods for positionally selective remote C-H functionalizations are in high demand. Herein, we disclose the first heterogeneous ruthenium catalyst for meta-selective C-H functionalizations, which enabled remote halogenations with excellent site selectivity and ample scope. The versatile heterogeneous Ru@SiO 2 catalyst was broadly applicable and could be easily recovered and reused, which set the stage for the direct fluorescent labeling of purines. In contrast to palladium, rhodium, iridium, or cobalt complexes, solely the ruthenium catalysis manifold provided access to meta-halogenated purine derivatives, illustrating the unique power of ruthenium C-H activation catalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Drift and Hysteresis Characteristics of Drug Sensors Based on Ruthenium Dioxide Membrane

    Directory of Open Access Journals (Sweden)

    Jung-Chuan Chou

    2008-09-01

    Full Text Available The drug sensing properties of procaine and berberine drug sensors based on ruthenium dioxide thin film were investigated. Ruthenium dioxide (RuO2 membrane prepared using a sputtering method was used as substrates for the drug sensors. The procaine and berberine drug sensors were prepared using a drug-sensitive membrane that measured the procaine and berberine concentration in a linear range from 1×10-2 M to 1×10-6 M and from 1×10-2 M to 1×10-7 M, respectively. The drift rates and hyteresis widths of these ruthenium dioxide based drug sensors were also investigated.

  15. Rotation of hard particles in a soft matrix

    Science.gov (United States)

    Yang, Weizhu; Liu, Qingchang; Yue, Zhufeng; Li, Xiaodong; Xu, Baoxing

    Soft-hard materials integration is ubiquitous in biological materials and structures in nature and has also attracted growing attention in the bio-inspired design of advanced functional materials, structures and devices. Due to the distinct difference in their mechanical properties, the rotation of hard phases in soft matrixes upon deformation has been acknowledged, yet is lack of theory in mechanics. In this work, we propose a theoretical mechanics framework that can describe the rotation of hard particles in a soft matrix. The rotation of multiple arbitrarily shaped, located and oriented particles with perfectly bonded interfaces in an elastic soft matrix subjected to a far-field tensile loading is established and analytical solutions are derived by using complex potentials and conformal mapping methods. Strong couplings and competitions of the rotation of hard particles among each other are discussed by investigating numbers, relative locations and orientations of particles in the matrix at different loading directions. Extensive finite element analyses are performed to validate theoretical solutions and good agreement of both rotation and stress field between them are achieved. Possible extensions of the present theory to non-rigid particles, viscoelastic matrix and imperfect bonding are also discussed. Finally, by taking advantage of the rotation of hard particles, we exemplify an application in a conceptual design of soft-hard material integrated phononic crystal and demonstrate that phononic band gaps can be successfully tuned with a high accuracy through the mechanical tension-induced rotation of hard particles. The present theory established herein is expected to be of immediate interests to the design of soft-hard materials integration based functional materials, structures and devices with tunable performance via mechanical rotation of hard phases.

  16. Turning conditions of Ck 45 steel with alternate hardness zones

    OpenAIRE

    A. Stoić; J. Kopač; T. Ergić; M. Duspar

    2009-01-01

    Purpose: of this paper is investigation of dynamic impacts on cutting edge during machining of locally hardened steel. Alteration of hardness on a single work piece is a source of impact on tool, which could lead to breakage of cutting tool and work piece surface damage in turning. Influence of material properties (primary hardness) is important when work piece is hardened locally by induction and part of material is soft annealed.Design/methodology/approach: Experimental tests of cutting out...

  17. Revisiting the definition of local hardness and hardness kernel.

    Science.gov (United States)

    Polanco-Ramírez, Carlos A; Franco-Pérez, Marco; Carmona-Espíndola, Javier; Gázquez, José L; Ayers, Paul W

    2017-05-17

    An analysis of the hardness kernel and local hardness is performed to propose new definitions for these quantities that follow a similar pattern to the one that characterizes the quantities associated with softness, that is, we have derived new definitions for which the integral of the hardness kernel over the whole space of one of the variables leads to local hardness, and the integral of local hardness over the whole space leads to global hardness. A basic aspect of the present approach is that global hardness keeps its identity as the second derivative of energy with respect to the number of electrons. Local hardness thus obtained depends on the first and second derivatives of energy and electron density with respect to the number of electrons. When these derivatives are approximated by a smooth quadratic interpolation of energy, the expression for local hardness reduces to the one intuitively proposed by Meneses, Tiznado, Contreras and Fuentealba. However, when one combines the first directional derivatives with smooth second derivatives one finds additional terms that allow one to differentiate local hardness for electrophilic attack from the one for nucleophilic attack. Numerical results related to electrophilic attacks on substituted pyridines, substituted benzenes and substituted ethenes are presented to show the overall performance of the new definition.

  18. Thermochemistry and Molecular Structure of a Remarkable Agostic Interaction in a Heterobifunctional Ruthenium-Boron Complex

    Science.gov (United States)

    Conley, Brian L.; Williams, Travis J.

    2010-01-01

    A boron-pendant ruthenium species forms a unique agostic methyl bridge between the boron and ruthenium atoms in the presence of a ligating solvent, acetonitrile. NMR inversion-recovery experiments enable measurement of the activation and equilibrium thermochemistry for formation of the agostic bridge. The mechanism for bridge formation involves displacement of an acetonitrile ligand; thus, this is a rare example of a case where an agostic C—H ligand competitively displaces another tight-binding ligand from a coordinatively saturated complex. Characterization of this complex gives unique insights into development of C—H activation catalysis based on this ligand-metal bifunctional motif. PMID:20088526

  19. Highly Active Ruthenium Metathesis Catalysts Exhibiting Unprecedented Activity and Z-Selectivity

    Science.gov (United States)

    Rosebrugh, Lauren E.; Herbert, Myles B.; Marx, Vanessa M.; Keitz, Benjamin K.; Grubbs, Robert H.

    2013-01-01

    A novel chelated ruthenium-based metathesis catalyst bearing an N-2,6-diisopropylphenyl group is reported and displays near-perfect selectivity for the Z-olefin (>95%), as well as unparalleled TONs of up to 7400, in a variety of homodimerization and industrially relevant metathesis reactions. This derivative and other new catalytically-active species were synthesized using an improved method employing sodium carboxylates to induce the salt metathesis and C-H activation of these chelated complexes. All of these new ruthenium-based catalysts are highly Z-selective in the homodimerization of terminal olefins. PMID:23317178

  20. Dye sensitized photovoltaic cells: Attaching conjugated polymers to zwitterionic ruthenium dyes

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Biancardo, M.

    2006-01-01

    The synthesis of a zwitterionic ruthenium dye that binds to anatase surfaces and has a built-in functionality that allows for the attachment of a conjugated polymer chain is presented. The system was found to adsorb on the surface of anatase anchored by the ruthenium dye. Two types of devices were...... and the complex was adsorbed onto the surface before evaporation of gold electrodes. Alternative devices were obtained by spincoating of the polymer solution onto PEDOT:PSS covered indium-doped tin oxide substrates. PEC solar cells gave the best results and the main finding was that the polymer chain served...

  1. Bis(Cyclic Alkyl Amino Carbene) Ruthenium Complexes: A Versatile, Highly Efficient Tool for Olefin Metathesis.

    Science.gov (United States)

    Gawin, Rafał; Kozakiewicz, Anna; Guńka, Piotr A; Dąbrowski, Paweł; Skowerski, Krzysztof

    2017-01-19

    The state-of-the-art in olefin metathesis is application of N-heterocyclic carbene (NHC)-containing ruthenium alkylidenes for the formation of internal C=C bonds and of cyclic alkyl amino carbene (CAAC)-containing ruthenium benzylidenes in the production of terminal olefins. A straightforward synthesis of bis(CAAC)Ru indenylidene complexes, which are highly effective in the formation of both terminal and internal C=C bonds at loadings as low as 1 ppm, is now reported. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The Hardness and Strength Properties of WC-Co Composites

    Science.gov (United States)

    Armstrong, Ronald W.

    2011-01-01

    The industrially-important WC-Co composite materials provide a useful, albeit complicated materials system for understanding the combined influences on hardness and strength properties of the constituent WC particle strengths, the particle sizes, their contiguities, and of Co binder hardness and mean free paths, and in total, the volume fraction of constituents. A connection is made here between the composite material properties, especially including the material fracture toughness, and the several materials-type considerations of: (1) related hardness stress-strain behaviors; (2) dislocation (viscoplastic) thermal activation characterizations; (3) Hall-Petch type reciprocal square root of particle or grain size dependencies; and (4) indentation and conventional fracture mechanics results. Related behaviors of MgO and Al2O3 crystal and polycrystal materials are also described for the purpose of making comparisons. PMID:28824143

  3. The Hardness and Strength Properties of WC-Co Composites

    Directory of Open Access Journals (Sweden)

    Ronald W. Armstrong

    2011-07-01

    Full Text Available The industrially-important WC-Co composite materials provide a useful, albeit complicated materials system for understanding the combined influences on hardness and strength properties of the constituent WC particle strengths, the particle sizes, their contiguities, and of Co binder hardness and mean free paths, and in total, the volume fraction of constituents. A connection is made here between the composite material properties, especially including the material fracture toughness, and the several materials-type considerations of: (1 related hardness stress-strain behaviors; (2 dislocation (viscoplastic thermal activation characterizations; (3 Hall-Petch type reciprocal square root of particle or grain size dependencies; and (4 indentation and conventional fracture mechanics results. Related behaviors of MgO and Al2O3 crystal and polycrystal materials are also described for the purpose of making comparisons.

  4. Microstructure and Hardness Distribution of Resistance Welded Advanced High Strength Steels

    DEFF Research Database (Denmark)

    Pedersen, Kim Richardt; Harthøj, Anders; Friis, Kasper Leth

    2008-01-01

    In this work a low carbon steel and two high strength steels (DP600 and TRIP700) have been resistance lap welded and the hardness profiles were measured by micro hardness indentation of cross sections of the joint. The resulting microstructure of the weld zone of the DP-DP and TRIP-TRIP joints were...... found to consist of a martensitic structure with a significant increase in hardness. Joints of dissimilar materials mixed completely in the melted region forming a new alloy with a hardness profile lying in between the hardness measured in joints of the similar materials. Furthermore the joints were...... simulated numerically and together with the material carbon equivalent, austenization temperatures and the thermal history the simulations were used to estimate the resulting post weld hardness using the commercial FE code SORPAS. The hardness of the welds of dissimilar materials was estimated...

  5. Hard photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, M. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier / CNRS-IN2P3, 53 Avenue des Martyrs, F-38026 Grenoble (France)

    2007-07-01

    In view of possible photoproduction studies in ultra-peripheral heavy-ion collisions at the LHC, we briefly review the present theoretical understanding of photons and hard photoproduction processes at HERA, discussing the production of jets, light and heavy hadrons, quarkonia, and prompt photons. We address in particular the extraction of the strong coupling constant from photon structure function and inclusive jet measurements, the infrared safety and computing time of jet definitions, the sensitivity of di-jet cross sections on the parton densities in the photon, factorization breaking in diffractive di-jet production, the treatment of the heavy-quark mass in charm production, the relevance of the color-octet mechanism for quarkonium production, and isolation criteria for prompt photons. (author)

  6. Dynamic Hardness Tester and Cure Meter

    Science.gov (United States)

    Madigosky, Walter M.; Fiorito, Ralph B.

    1993-01-01

    The Shore hardness tester is used extensively throughout industry to determine the static modulus of materials. The new apparatus described here extends the capability of an indentor-type tester into the dynamic regime, and provides a measurement of the dynamic shear or Young's modulus and loss factor as a function of frequency. The instrument, model and data of typical rubber samples are given and compared to other dynamic measurements.

  7. Results of PWO Radiation Hardness Optimization.

    CERN Document Server

    Drobychev, Gleb; Auffray, Etiennette; Borisevich, A E; Korzhik, Mikhail; Kostylev, V; Lecoq, Paul; Ligoun, V D; Peigneux, Jean-Pierre

    1999-01-01

    The results of analysis of the PWO radiation hardness depending of crystal growth technology are presented. The PWO crystals of different crystallization numbers with one kind of doping and double doped as well as crystals grown from recycled raw materials were analyzed. The presented results show high level of crystal technology reproducibility. More than 95% of double doped crystals satisfy to the CMS ECAL specification requirements.

  8. Probing the Quenching of Quantum Dot Photoluminescence by Peptide-Labeled Ruthenium(II) Complexes.

    Science.gov (United States)

    Scott, Amy M; Algar, W Russ; Stewart, Michael H; Trammell, Scott A; Blanco-Canosa, Juan B; Dawson, Philip E; Deschamps, Jeffrey R; Goswami, Ramasis; Oh, Eunkeu; Huston, Alan L; Medintz, Igor L

    2014-05-01

    Charge transfer processes with semiconductor quantum dots (QDs) have generated much interest for potential utility in energy conversion. Such configurations are generally nonbiological; however, recent studies have shown that a redox-active ruthenium(II)-phenanthroline complex (Ru(2+)-phen) is particularly efficient at quenching the photoluminescence (PL) of QDs, and this mechanism demonstrates good potential for application as a generalized biosensing detection modality since it is aqueous compatible. Multiple possibilities for charge transfer and/or energy transfer mechanisms exist within this type of assembly, and there is currently a limited understanding of the underlying photophysical processes in such biocomposite systems where nanomaterials are directly interfaced with biomolecules such as proteins. Here, we utilize redox reactions, steady-state absorption, PL spectroscopy, time-resolved PL spectroscopy, and femtosecond transient absorption spectroscopy (FSTA) to investigate PL quenching in biological assemblies of CdSe/ZnS QDs formed with peptide-linked Ru(2+)-phen. The results reveal that QD quenching requires the Ru(2+) oxidation state and is not consistent with Förster resonance energy transfer, strongly supporting a charge transfer mechanism. Further, two colors of CdSe/ZnS core/shell QDs with similar macroscopic optical properties were found to have very different rates of charge transfer quenching, by Ru(2+)-phen with the key difference between them appearing to be the thickness of their ZnS outer shell. The effect of shell thickness was found to be larger than the effect of increasing distance between the QD and Ru(2+)-phen when using peptides of increasing persistence length. FSTA and time-resolved upconversion PL results further show that exciton quenching is a rather slow process consistent with other QD conjugate materials that undergo hole transfer. An improved understanding of the QD-Ru(2+)-phen system can allow for the design of more

  9. Probing the Quenching of Quantum Dot Photoluminescence by Peptide-Labeled Ruthenium(II) Complexes

    Science.gov (United States)

    2015-01-01

    Charge transfer processes with semiconductor quantum dots (QDs) have generated much interest for potential utility in energy conversion. Such configurations are generally nonbiological; however, recent studies have shown that a redox-active ruthenium(II)–phenanthroline complex (Ru2+-phen) is particularly efficient at quenching the photoluminescence (PL) of QDs, and this mechanism demonstrates good potential for application as a generalized biosensing detection modality since it is aqueous compatible. Multiple possibilities for charge transfer and/or energy transfer mechanisms exist within this type of assembly, and there is currently a limited understanding of the underlying photophysical processes in such biocomposite systems where nanomaterials are directly interfaced with biomolecules such as proteins. Here, we utilize redox reactions, steady-state absorption, PL spectroscopy, time-resolved PL spectroscopy, and femtosecond transient absorption spectroscopy (FSTA) to investigate PL quenching in biological assemblies of CdSe/ZnS QDs formed with peptide-linked Ru2+-phen. The results reveal that QD quenching requires the Ru2+ oxidation state and is not consistent with Förster resonance energy transfer, strongly supporting a charge transfer mechanism. Further, two colors of CdSe/ZnS core/shell QDs with similar macroscopic optical properties were found to have very different rates of charge transfer quenching, by Ru2+-phen with the key difference between them appearing to be the thickness of their ZnS outer shell. The effect of shell thickness was found to be larger than the effect of increasing distance between the QD and Ru2+-phen when using peptides of increasing persistence length. FSTA and time-resolved upconversion PL results further show that exciton quenching is a rather slow process consistent with other QD conjugate materials that undergo hole transfer. An improved understanding of the QD–Ru2+-phen system can allow for the design of more sophisticated

  10. Chemical bonding and optoelectrical properties of ruthenium doped yttrium oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lei; Han, Jiecai [Harbin Institute of Technology, Harbin 150080 (China); Zhu, Jiaqi, E-mail: zhujq@hit.edu.cn [Harbin Institute of Technology, Harbin 150080 (China); Zhu, Yuankun [Harbin Institute of Technology, Harbin 150080 (China); Schlaberg, H.Inaki [North China Electric Power University, Beijing 102206 (China)

    2013-11-15

    Graphical abstract: IR transmittance of various transparent conductive materials (RYO films grown under RT, 400 °C and 600 °C, ITO films [2], Carbon Nano tube films [11], metal/dielectric multilayers [12]). - Highlights: • Y{sub 2}O{sub 3}:Ru (RYO) films were prepared on ZnS substrates by reactive magnetron sputtering. • Ru doping significantly decreases the resistivity and extends the transparent range. • Optical and electrical properties of RYO films can be tuned by substrate temperatures. • The RYO films exhibit excellent far-IR transmittance and electrical property. - Abstract: Highly infrared transparent conductive ruthenium doped yttrium oxide (RYO) films were deposited on zinc sulfide and glass substrates by reactive magnetron sputtering. The structural, optical, and electrical properties of the films as a function of growth temperature were studied. It is shown that the sputtered RYO thin films are amorphous and smooth surface is obtained. The infrared transmittance of the films increases with increasing the growth temperature. RYO films maintain greater than ∼65% transmittance over a wide wavelength range from 2.5 μm to 12 μm and the highest transmittance value reaches 73.3% at ∼10 μm. With increasing growth temperature, the resistivity changed in a wide range and lowest resistivity of about 3.36 × 10{sup −3} Ω cm is obtained at room temperature. The RYO thin films with high conductivity and transparency in IR spectral range would be suitable for infrared optical and electromagnetic shielding devices.

  11. Hardness of metallic crystals

    Indian Academy of Sciences (India)

    Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China; Henan Key Laboratory of Advanced Non-ferrous Metals, Luoyang 471003, China; School of Materials Science and Engineering, Henan University of Science and Technology, ...

  12. Ruthenium Water Oxidation Catalysts based on Pentapyridyl Ligands.

    Science.gov (United States)

    Gil-Sepulcre, Marcos; Böhler, Michael; Schilling, Mauro; Bozoglian, Fernando; Bachmann, Cyril; Scherrer, Dominik; Fox, Thomas; Spingler, Bernhard; Gimbert-Suriñach, Carolina; Alberto, Roger; Bofill, Roger; Sala, Xavier; Luber, Sandra; Richmond, Craig J; Llobet, Antoni

    2017-11-23

    Ruthenium complexes containing the pentapyridyl ligand 6,6''-(methoxy(pyridin-2-yl)methylene)di-2,2'-bipyridine (L-OMe) of general formula trans-[Ru II (X)(L-OMe-κ-N 5 )] n+ (X=Cl, n=1, trans-1 + ; X=H 2 O, n=2, trans-2 2+ ) have been isolated and characterized in solution (by NMR and UV/Vis spectroscopy) and in the solid state by XRD. Both complexes undergo a series of substitution reactions at oxidation state Ru II and Ru III when dissolved in aqueous triflic acid-trifluoroethanol solutions as monitored by UV/Vis spectroscopy, and the corresponding rate constants were determined. In particular, aqueous solutions of the Ru III -Cl complex trans-[Ru III (Cl)(L-OMe-κ-N 5 )] 2+ (trans-1 2+ ) generates a family of Ru aquo complexes, namely trans-[Ru III (H 2 O)(L-OMe-κ-N 5 )] 3+ (trans-2 3+ ), [Ru III (H 2 O) 2 (L-OMe-κ-N 4 )] 3+ (trans-3 3+ ), and [Ru III (Cl)(H 2 O)(L-OMe-κ-N 4 )] 2+ (trans-4 2+ ). Although complex trans-4 2+ is a powerful water oxidation catalyst, complex trans-2 3+ has only a moderate activity and trans-3 3+ shows no activity. A parallel study with related complexes containing the methyl-substituted ligand 6,6''-(1-pyridin-2-yl)ethane-1,1-diyl)di-2,2'-bipyridine (L-Me) was carried out. The behavior of all of these catalysts has been rationalized based on substitution kinetics, oxygen evolution kinetics, electrochemical properties, and density functional theory calculations. The best catalyst, trans-4 2+ , reaches turnover frequencies of 0.71 s -1 using Ce IV as a sacrificial oxidant, with oxidative efficiencies above 95 %. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Dealloyed Ruthenium Film Catalysts for Hydrogen Generation from Chemical Hydrides

    Directory of Open Access Journals (Sweden)

    Ramis B. Serin

    2017-07-01

    Full Text Available Thin-film ruthenium (Ru and copper (Cu binary alloys have been prepared on a Teflon™ backing layer by cosputtering of the precious and nonprecious metals, respectively. Alloys were then selectively dealloyed by sulfuric acid as an etchant, and their hydrogen generation catalysts performances were evaluated. Sputtering time and power of Cu atoms have been varied in order to tailor the hydrogen generation performances. Similarly, dealloying time and the sulfuric acid concentration have also been altered to tune the morphologies of the resulted films. A maximum hydrogen generation rate of 35 mL min−1 was achieved when Cu sputtering power and time were 200 W and 60 min and while acid concentration and dealloying time were 18 M and 90 min, respectively. It has also been demonstrated that the Ru content in the alloy after dealloying gradually increased with the increasing the sputtering power of Cu. After 90 min dealloying, the Ru to Cu ratio increased to about 190 times that of bare alloy. This is the key issue for observing higher catalytic activity. Interestingly, we have also presented template-free nanoforest-like structure formation within the context of one-step alloying and dealloying used in this study. Last but not least, the long-time hydrogen generation performances of the catalysts system have also been evaluated along 3600 min. During the first 600 min, the catalytic activity was quite stable, while about 24% of the catalytic activity decayed after 3000 min, which still makes these systems available for the development of robust catalyst systems in the area of hydrogen generation.

  14. Reaction mechanisms of ruthenium tetroxide mediated oxidations of organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Froehaug, Astrid Elisabeth

    1995-12-31

    This thesis reports a study of the mechanism of ruthenium tetroxide mediated oxidations of saturated hydrocarbons, ethers, alkenes and alcohols. Several methods were used. The RuO{sub 4}-mediated oxidations of adamantane and cis-decalin were studied in CCl{sub 4}-CH{sub 3}CN-H{sub 2}O and in acetone-water. The rate of reaction was found to be moderately influenced by the polarity of the solvent. Solvent properties other than the polarity were also found to influence the reaction rates. From the oxidations of adamantane and adamantane-1,3,5,7-d{sub 4} two primary kinetic deuterium isotope effects were found. These were comparable with the deuterium isotope effects found for the analogous oxidations of cis-decalin and cis-decalin-d{sub 18}. The results seem to exclude both a one step hydride abstraction reaction mechanism and a one step concerted mechanism, as well as a scheme where two such mechanisms compete. The observations may be explained by a two step reaction mechanism consisting of a pre-equilibrium with formation of a substrate-RuO{sub 4} complex followed by a concerted rate determining reaction. The RuO{sub 4}-mediated oxidation of ethers was of kinetic second order with a small enthalpy of activation and a large negative entropy of activation. Oxidation of cyclopropylmethyl methyl ether gave methyl cyclopropanecarboxylate, no rearranged products were observed. On RuO{sub 4} oxidations in CCl{sub 4} with NaIO{sub 4} as stoichiometric oxidant, no chlorinated products were observed. Several observations not in agreement with a hydride or a hydrogen abstraction mechanism may be explained by assuming that the reaction proceeds by either a concerted reaction or by a reversible oxidative addition of the ether to RuO{sub 4} followed by a slow concerted step. 228 refs., 9 figs., 27 tabs.

  15. Janka hardness using nonstandard specimens

    Science.gov (United States)

    David W. Green; Marshall Begel; William Nelson

    2006-01-01

    Janka hardness determined on 1.5- by 3.5-in. specimens (2×4s) was found to be equivalent to that determined using the 2- by 2-in. specimen specified in ASTM D 143. Data are presented on the relationship between Janka hardness and the strength of clear wood. Analysis of historical data determined using standard specimens indicated no difference between side hardness...

  16. Hard particle effect on surface generation in nano-cutting

    Science.gov (United States)

    Xu, Feifei; Fang, Fengzhou; Zhang, Xiaodong

    2017-12-01

    The influence of the hard particle on the surface generation, plastic deformation and processing forces in nano-cutting of aluminum is investigated by means of molecular dynamics simulations. In this investigation, a hard particle which is simplified as a diamond ball is embedded under the free surface of workpiece with different depths. The influence of the position of the hard ball on the surface generation and other material removal mechanism, such as the movement of the ball under the action of cutting tool edge, is revealed. The results show that when the hard particle is removed, only a small shallow pit is left on the machined surface. Otherwise, it is pressed down to the subsurface of the workpiece left larger and deeper pit on the generated surface. Besides that, the hard particle in the workpiece would increase the processing force when the cutting tool edge or the plastic carriers interact with the hard particle. It is helpful to optimize the cutting parameters and material properties for obtaining better surface quality in nano-cutting of composites or other materials with micro/nanoscale hard particles in it.

  17. 2TB hard disk drive

    CERN Multimedia

    This particular object was used up until 2012 in the Data Centre. It slots into one of the Disk Server trays. Hard disks were invented in the 1950s. They started as large disks up to 20 inches in diameter holding just a few megabytes (link is external). They were originally called "fixed disks" or "Winchesters" (a code name used for a popular IBM product). They later became known as "hard disks" to distinguish them from "floppy disks (link is external)." Hard disks have a hard platter that holds the magnetic medium, as opposed to the flexible plastic film found in tapes and floppies.

  18. Undoped and boron doped diamond nanoparticles as platinum and platinum-ruthenium catalyst support for direct methanol fuel cell application

    Science.gov (United States)

    La Torre Riveros, Lyda

    Nanoparticular diamond is a promising material that can be used as a robust and chemically stable catalytic support. It has been studied and characterized physically and electrochemically, in its powder and thin film forms. This thesis work intends to demonstrate that undoped diamond nanoparticles (DNPs) and boron-doped diamond nanoparticles (BDDNPs) can be used as an electrode and a catalytic support material for platinum and ruthenium catalysts. The electrochemical properties of diamond nanoparticle electrodes, fabricated using the ink paste method, were investigated. As an initial step, we carried out chemical purification of commercially available undoped DNPs by refluxing in aqueous HNO3 as well as of BDDNPs which were doped through a collaborative work with the University of Missouri. The purified material was characterized by spectroscopic and surface science techniques. The reversibility of reactions such as ferricyanide/ferrocyanide (Fe(CN) 63-/Fe(CN)64-) and hexaamineruthenium (III) chloride complexes as redox probes were evaluated by cyclic voltammetry at the undoped DNPs and BDDNPs surface. These redox probes showed limited peak currents and presented linear relationships between current (i) and the square root of the potential scan rate (v1/2). However, compared to conventional electrodes, the peak currents were smaller. BDDNPs show an improvement in charge transfer currents when compared to undoped DNPs. Platinum and ruthenium nanoparticles were chemically deposited on undoped DNPs and BDDNPs through the use of the excess of a mild reducing agent such NaBH4. In order to improve the nanoparticle dispersion sodium dodecyl benzene sulfonate (SDBS), a surfactant agent, was used. Percentages of platinum and ruthenium metals were varied as well as the stoichiometric amount of the reducing agent to determine adequate parameters for optimum performance in methanol oxidation. Both before and after the reducing process the samples were characterized by scanning

  19. Atomic Layer Deposition of Ruthenium with TiN Interface for Sub-10 nm Advanced Interconnects beyond Copper

    DEFF Research Database (Denmark)

    Wen, Liang Gong; Roussel, Philippe; Pedreira, Olalla Varela

    2016-01-01

    Atomic layer deposition of ruthenium is studied as a barrierless metallization solution for future sub-10 nm interconnect technology nodes. We demonstrate the void-free filling in sub-10 nm wide single damascene lines using an ALD process in combination with 2.5 angstrom of ALD TiN interface and po......'stdeposition annealing. At such small dimensions, the ruthenium effective resistance depends less on the scaling than that of Cu/barrier systems. Ruthenium effective resistance potentially crosses the Cu curve at 14 and 10 nm according to the semiempirical interconnect resitance model for advanced technology nodes...

  20. A study of ruthenium complexes of some biologically relevant a-N ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 112; Issue 3. A study of ruthenium complexes of some biologically relevant ∙ -N-heterocyclic ... Author Affiliations. P Sengupta1 S Ghosh1. Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Calcutta 700 032, India ...

  1. Lipase/Ruthenium-Catalyzed Dynamic Kinetic Resolution of β-Hydroxyalkyl ferrocene Derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Han Ki; Ahn, Yang Soo [Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2004-10-15

    An efficient dynamic kinetic resolution of racemic β-hydroxyalkyl ferrocene and 1,1'-bis(β-hydroxyalkyl)- ferrocene derivatives was achieved using lipase/ruthenium-catalyzed transesterification in the presence of an acyl donor. The racemic β-hydroxyalkyl ferrocene derivatives were successfully transformed to the corresponding chiral acetates of high optical purities in high yields.

  2. Investigation of Ruthenium Dissolution in Advanced Membrane Electrode Assemblies for Direct Methanol Based Fuel Cell Stacks

    Science.gov (United States)

    Valdez, Thomas I.; Firdosy, S.; Koel, B. E.; Narayanan, S. R.

    2005-01-01

    Dissolution of ruthenium was observed in the 80-cell stack. Duration testing was performed in single cell MEAs to determine the pathway of cell degradation. EDAX analysis on each of the single cell MEAs has shown that the Johnson Matthey commercial catalyst is stable in DMFC operation for 250 hours, no ruthenium dissolution was observed. Changes in the hydrophobicity of the cathode backing papers was minimum. Electrode polarization analysis revealed that the MEA performance loss is attributed to changes in the cathode catalyst layer. Ruthenium migration does not seem to occur during cell operation but can occur when methanol is absent from the anode compartment, the cathode compartment has access to air, and the cells in the stack are electrically connected to a load (Shunt Currents). The open-to-air cathode stack design allowed for: a) The MEAs to have continual access to oxygen; and b) The stack to sustain shunt currents. Ruthenium dissolution in a DMFC stack can be prevented by: a) Developing an internally manifolded stacks that seal reactant compartments when not in operation; b) Bringing the cell voltages to zero quickly when not in operation; and c) Limiting the total number of cells to 25 in an effort to limit shunt currents.

  3. Investigation of Ruthenium Dissolution in Advanced Membrane Electrode Assemblies for Direct Methanol Based Fuel Cells Stacks

    Science.gov (United States)

    Valdez, T. I.; Firdosy, S.; Koel, B. E.; Narayanan, S. R.

    2005-01-01

    This viewgraph presentation gives a detailed review of the Direct Methanol Based Fuel Cell (DMFC) stack and investigates the Ruthenium that was found at the exit of the stack. The topics include: 1) Motivation; 2) Pathways for Cell Degradation; 3) Cell Duration Testing; 4) Duration Testing, MEA Analysis; and 5) Stack Degradation Analysis.

  4. Z-Selective Homodimerization of Terminal Olefins with a Ruthenium Metathesis Catalyst

    Science.gov (United States)

    Keitz, Benjamin K.; Endo, Koji; Herbert, Myles B.

    2011-01-01

    The cross-metathesis of terminal olefins using a novel ruthenium catalyst results in excellent selectivity for the Z-olefin homodimer. The reaction was found to tolerate a large number of functional groups, solvents, and temperatures while maintaining excellent Z-selectivity, even at high reaction conversions. PMID:21649443

  5. The doping effect of fluorinated aromatic solvents on the rate of ruthenium-catalysed olefin metathesis.

    Science.gov (United States)

    Samojłowicz, Cezary; Bieniek, Michał; Pazio, Aleksandra; Makal, Anna; Woźniak, Krzysztof; Poater, Albert; Cavallo, Luigi; Wójcik, Jacek; Zdanowski, Konrad; Grela, Karol

    2011-11-11

    A study concerning the effect of using a fluorinated aromatic solvent as the medium for olefin metathesis reactions catalysed by ruthenium complexes bearing N-heterocyclic carbene ligands is presented. The use of fluorinated aromatic hydrocarbons (FAH) as solvents for olefin metathesis reactions catalysed by standard commercially available ruthenium pre-catalysts allows substantially higher yields of the desired products to be obtained, especially in the case of demanding polyfunctional molecules, including natural and biologically active compounds. Interactions between the FAH and the second-generation ruthenium catalysts, which apparently improve the efficiency of the olefin metathesis transformation, have been studied by X-ray structure analysis and computations, as well as by carrying out a number of metathesis experiments. The optimisation of reaction conditions by using an FAH can be regarded as a complementary approach for the design of new improved ruthenium catalysts. Fluorinated aromatic solvents are an attractive alternative medium for promoting challenging olefin metathesis reactions. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Structural, spectral, DFT and biological studies on macrocyclic mononuclear ruthenium (II) complexes

    Science.gov (United States)

    Muthukkumar, M.; Kamal, C.; Venkatesh, G.; Kaya, C.; Kaya, S.; Enoch, Israel V. M. V.; Vennila, P.; Rajavel, R.

    2017-11-01

    Macrocyclic mononuclear ruthenium (II) complexes have been synthesized by condensation method [Ru (L1, L2, L3) Cl2] L1 = (C36 H31 N9), L2= (C42H36N8), L3= (C32H32 N8)]. These ruthenium complexes have been established by elemental analyses and spectroscopic techniques (Fourier transform infrared spectroscopy (FT-IR), 1H- nuclear magnetic resonance (NMR), 13C- NMR and Electrospray ionization mass spectrometry (ESI-MS)). The coordination mode of the ligand has been confirmed and the octahedral geometry around the ruthenium ion has been revealed. Binding affinity and binding mode of ruthenium (II) complexes with Bovine serum Albumin (BSA) have been characterized by Emission spectra analysis. UV-Visible and fluorescence spectroscopic techniques have also been utilized to examine the interaction between ligand and its complexes L1, L2, & L3 with BSA. Chemical parameters and molecular structure of Ru (II) complexes L1H, L2H, & L3H have been determined by DFT coupled with B3LYP/6-311G** functional in both the gaseous and aqueous phases.

  7. Aerobic Oxidation of 5-(Hydroxymethyl)furfural in Ionic Liquids with Solid Ruthenium Hydroxide Catalysts

    DEFF Research Database (Denmark)

    Ståhlberg, Tim Johannes Bjarki; Eyjolfsdottir, Ester; Gorbanev, Yury

    2012-01-01

    The aerobic oxidation of 5-(hydroxymethyl)furfural was investigated over solid ruthenium hydroxide catalysts in ionic liquids at elevated temperatures and pressures. Several different catalyst supports were tested in combination with various ionic liquids. The best result was obtained in [EMIm...

  8. Asymmetric hydrogenation of aromatic ketones by new recyclable ionic tagged ferrocene-ruthenium catalyst system.

    Science.gov (United States)

    Xu, Di; Zhou, Zhi-Ming; Dai, Li; Tang, Li-Wei; Zhang, Jun

    2015-05-01

    Newly developed ferrocene-oxazoline-phosphine ligands containing quaternary ammonium ionic groups exhibited excellent catalytic performance for the ruthenium-catalyzed hydrogenation of aromatic ketonic substrates to give chiral secondary alcohols with high levels of conversions and enantioselectivities. Simple manipulation process, water tolerance, high activity and good recyclable property make this catalysis practical and appealing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Olefin Ring Closing Metathesis and Hydrosilylation Reaction in Aqueous Medium by Grubbs Second Generation Ruthenium Catalyst

    Science.gov (United States)

    The Grubbs second generation ruthenium catalyst was shown to catalyze various olefin ring closing metathesis and hydrosilylation reactions in aqueous medium. Reactions proceeded in pure water without any additives or co-solvents, in a short period of time. We found that inhomogen...

  10. Determination of trace amounts of ruthenium with dithizone by means of substoichiometric isotope dilution analysis

    Energy Technology Data Exchange (ETDEWEB)

    Roebisch, G.; Schober, W.; Dietel, R. (Paedagogische Hochschule Karl Liebknecht, Potsdam (German Democratic Republic). Sektion Chemie/Biologie)

    1983-01-01

    Hexachlororuthenat(III) and the ruthenylion (RuO/sup 2 +/) react with dithizone on heating in weakly acidic water-ethanol solution. The complexes formed can be extracted into chloroform. Based on this reaction, a reproducible, selective determination of ruthenium (20 ppb) is achieved by means of substoichiometric isotope dilution analysis, using /sup 106/Ru.

  11. Cobalt (III), nickel (II) and ruthenium (II) complexes of 1, 10 ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 112; Issue 1. Cobalt(III), nickel(II) and ruthenium(II) complexes of 1,10-phenanthroline family of ligands: DNA binding and photocleavage studies. S Arounaguiri D Easwaramoorthy A Ashokkumar Aparna Dattagupta Bhaskar G Maiya. Inorganic and Analytical Volume ...

  12. One-Pot Formation of Functionalized Indole and Benzofuran Derivatives Using a Single Bifunctional Ruthenium Catalyst

    OpenAIRE

    Nair, Reji N.; Lee, Paul J.; Grotjahn, Douglas B

    2010-01-01

    We report a single bifunctional ruthenium catalyst for cyclization of terminal alkynylaryl amines and -phenols to corresponding indole and benzofuran derivatives in good yields. Key features the ability to cyclize and hydrate terminal alkynes in one step and to deuterate the heteroaromatic compounds formed.

  13. Biological properties of novel ruthenium- and osmium-nitrosyl complexes with azole heterocycles

    KAUST Repository

    Novak, Maria S.

    2016-03-09

    Since the discovery that nitric oxide (NO) is a physiologically relevant molecule, there has been great interest in the use of metal nitrosyl compounds as antitumor pharmaceuticals. Particularly interesting are those complexes which can deliver NO to biological targets. Ruthenium- and osmium-based compounds offer lower toxicity compared to other metals and show different mechanisms of action as well as different spectra of activity compared to platinum-based drugs. Novel ruthenium- and osmium-nitrosyl complexes with azole heterocycles were studied to elucidate their cytotoxicity and possible interactions with DNA. Apoptosis induction, changes of mitochondrial transmembrane potential and possible formation of reactive oxygen species were investigated as indicators of NO-mediated damage by flow cytometry. Results suggest that ruthenium- and osmium-nitrosyl complexes with the general formula (indazolium)[cis/trans-MCl4(NO)(1H-indazole)] have pronounced cytotoxic potency in cancer cell lines. Especially the more potent ruthenium complexes strongly induce apoptosis associated with depolarization of mitochondrial membranes, and elevated reactive oxygen species levels. Furthermore, a slight yet not unequivocal trend to accumulation of intracellular cyclic guanosine monophosphate attributable to NO-mediated effects was observed.

  14. Photo-induced DNA cleavage and cytotoxicity of a ruthenium(II) arene anticancer complex

    Czech Academy of Sciences Publication Activity Database

    Brabec, Viktor; Prachařová, J.; Štěpánková, Jana; Sadler, P. J.; Kašpárková, Jana

    2016-01-01

    Roč. 160, JUL2016 (2016), s. 149-155 ISSN 0162-0134 R&D Projects: GA ČR(CZ) GA14-21053S; GA MŠk(CZ) LD14019 Institutional support: RVO:68081707 Keywords : Ruthenium anticancer complex * DNA cleavage * Phototoxicity Subject RIV: BO - Biophysics Impact factor: 3.348, year: 2016

  15. Hydrogenation of esters catalyzed by ruthenium PN3-Pincer complexes containing an aminophosphine arm

    KAUST Repository

    Chen, Tao

    2014-08-11

    Hydrogenation of esters under mild conditions was achieved using air-stable ruthenium PN3-pincer complexes containing an aminophosphine arm. High efficiency was achieved even in the presence of water. DFT studies suggest a bimolecular proton shuttle mechanism which allows H2 to be activated by the relatively stable catalyst with a reasonably low transition state barrier. © 2014 American Chemical Society.

  16. Mechanistic study of ruthenium (III) catalysed oxidation of L-lysine by ...

    Indian Academy of Sciences (India)

    Administrator

    Mechanistic study of ruthenium (III) catalysed oxidation of L-lysine by diperiodatoargentate (III) in aqueous alkaline medium. R R HOSAMANI and S T NANDIBEWOOR*. PG Department of Studies in Chemistry, Karnatak University, Dharwad 580 003 e-mail: stnandibewoor@yahoo.com. MS received 15 April 2008; revised 2 ...

  17. Half-sandwich (η6-arene) ruthenium (II) chiral Schiff base ...

    Indian Academy of Sciences (India)

    sandwich (6-arene)ruthenium(II) chiral Schiff base complexes: Analysis of the diastereomeric mixtures in solution by 2D-NMR spectroscopy. Rakesh K Rath G A Nagana Gowda Akhil R Chakravarty. Inorganic and Analytical Volume 114 Issue 5 ...

  18. Kinetics and Photochemistry of Ruthenium Bisbipyridine Diacetonitrile Complexes: An Interdisciplinary Inorganic and Physical Chemistry Laboratory Exercise.

    Science.gov (United States)

    Rapp, Teresa L; Phillips, Susan R; Dmochowski, Ivan J

    2016-12-13

    The study of ruthenium polypyridyl complexes can be widely applied across disciplines in the undergraduate curriculum. Ruthenium photochemistry has advanced many fields including dye-sensitized solar cells, photoredox catalysis, light-driven water oxidation, and biological electron transfer. Equally promising are ruthenium polypyridyl complexes that provide a sterically bulky, photolabile moiety for transiently "caging" biologically active molecules. Photouncaging involves the use of visible (1-photon) or near-IR (2-photon) light to break one or more bonds between ruthenium and coordinated ligand(s), which can occur on short time scales and in high quantum yields. In this work we demonstrate the use of a model "caged" acetonitrile complex, Ru(2,2'-bipyridine) 2 (acetonitrile) 2 , or RuMeCN in an advanced synthesis and physical chemistry laboratory. Students made RuMeCN in an advanced synthesis laboratory course and performed UV-vis spectroscopy and electrochemistry. The following semester students investigated RuMeCN photolysis kinetics in a physical chemistry laboratory. These two exercises may also be combined to create a 2-week module in an advanced undergraduate laboratory course.

  19. An alternative pathway for production of acetonitrile: ruthenium catalysed aerobic dehydrogenation of ethylamine

    DEFF Research Database (Denmark)

    Corker, Emily; Mentzel, Uffe Vie; Mielby, Jerrik Jørgen

    2013-01-01

    The oxidative synthesis of acetonitrile from ethylamine was studied using a supported ruthenium catalyst. The reaction was conducted in both batch and flow processes and high conversions (over 85%) were achieved in both cases. Selectivity of both reactions was improved by optimisation of reaction...... for the independent and efficient production of acetonitrile....

  20. Upconverting nanovesicles for the activation of ruthenium anti-cancer prodrugs with red light

    NARCIS (Netherlands)

    Askes, S.H.C.

    2016-01-01

    Ruthenium complexes are promising prodrugs in photoactivated chemotherapy (PACT): to prevent systemic therapeutic side-effects, a non-toxic version of the drug is introduced in the body and is only activated at the place of the tumor by means of visible light irradiation. However, most of these PACT

  1. Hard coal; Steinkohle

    Energy Technology Data Exchange (ETDEWEB)

    Loo, Kai van de; Sitte, Andreas-Peter [Gesamtverband Steinkohle e.V. (GVSt), Herne (Germany)

    2015-07-01

    International the coal market in 2014 was the first time in a long time in a period of stagnation. In Germany, the coal consumption decreased even significantly, mainly due to the decrease in power generation. Here the national energy transition has now been noticable affected negative for coal use. The political guidances can expect a further significant downward movement for the future. In the present phase-out process of the German hard coal industry with still three active mines there was in 2014 no decommissioning. But the next is at the end of 2015, and the plans for the time after mining have been continued. [German] International war der Markt fuer Steinkohle 2014 erstmals seit langem wieder von einer Stagnation gekennzeichnet. In Deutschland ging der Steinkohlenverbrauch sogar deutlich zurueck, vor allem wegen des Rueckgangs in der Stromerzeugung. Hier hat sich die nationale Energiewende nun spuerbar und fuer die Steinkohlennutzung negativ ausgewirkt. Die politischen Weichenstellungen lassen fuer die Zukunft eine weitere erhebliche Abwaertsbewegung erwarten. Bei dem im Auslaufprozess befindlichen deutschen Steinkohlenbergbau mit noch drei aktiven Bergwerken gab es 2014 keine Stilllegung. Doch die naechste steht zum Jahresende 2015 an, und die Planungen fuer die Zeit nach dem Bergbau sind fortgefuehrt worden.

  2. Synthesis and reactivity of compounds containing ruthenium-carbon, -nitrogen, and -oxygen bonds

    Energy Technology Data Exchange (ETDEWEB)

    Hartwig, J.F.

    1990-12-01

    The products and mechanisms of the thermal reactions of several complexes of the general structure (PMe{sub 3}){sub 4}Ru(X)(Y) and (DMPM){sub 2}Ru(X)(Y) where X and Y are hydride, aryl, and benzyl groups, have been investigated. The mechanism of decomposition depends critically on the structure of the complex and the medium in which the thermolysis is carried out. The alkyl hydride complexes are do not react with alkane solvent, but undergo C-H activation processes with aromatic solvents by several different mechanisms. Thermolysis of (PMe{sub 3}){sub 4}Ru(Ph)(Me) or (PMe{sub 3}){sub 4}Ru(Ph){sub 2} leads to the ruthenium benzyne complex (PMe{sub 3}){sub 4}Ru({eta}{sup 2}-C{sub 6}H{sub 4}) (1) by a mechanism which involves reversible dissociation of phosphine. In many ways its chemistry is analogous to that of early rather than late organo transition metal complexes. The synthesis, structure, variable temperature NMR spectroscopy and reactivity of ruthenium complexes containing aryloxide or arylamide ligands are reported. These complexes undergo cleavage of a P-C bond in coordinated trimethylphosphine, insertion of CO and CO{sub 2} and hydrogenolysis. Mechanistic studies on these reactions are described. The generation of a series of reactive ruthenium complexes of the general formula (PMe{sub 3}){sub 4}Ru(R)(enolate) is reported. Most of these enolates have been shown to bind to the ruthenium center through the oxygen atom. Two of the enolate complexes 8 and 9 exist in equilibrium between the O- and C-bound forms. The reactions of these compounds are reported, including reactions to form oxygen-containing metallacycles. The structure and reactivity of these ruthenium metallacycles is reported, including their thermal chemistry and reactivity toward protic acids, electrophiles, carbon monoxide, hydrogen and trimethylsilane. 243 refs., 10 tabs.

  3. Outdoor weathering of facial prosthetic elastomers differing in Durometer hardness.

    Science.gov (United States)

    Willett, Emily S; Beatty, Mark W

    2015-03-01

    Facial prosthetic elastomers with wide ranges in hardness are available, yet material weatherability is unknown. The purpose of this study was to assess color, Durometer hardness, and tensile property changes after 3000 hours of outdoor weathering. Unpigmented elastomers with Durometer hardness 5, 30, 50, 70, and A-2186 were polymerized into dumbbells (ASTM D412) and disks, 34 mm in diameter by 6 mm thick. Materials were subjected to outdoor or time passage environments for 3000 hours. CIELab color (n=5), Durometer hardness (n=5), and tensile mechanical properties (n=10) were measured at 0 and 3000 hours, and group differences were assessed by material and weathering condition (ANOVA/Tukey, α=.05). Except for A-2186, the mean Durometer changes for all materials were 1 unit or less, with no significant differences observed between time passage and weathered groups (P≥.05). Three-thousand-hour tensile mechanical property results demonstrated nonsignificant differences between time passage and weathered materials but significantly changed properties from immediately tested materials (Phardness 5 and 30 and A-2186. With a few exceptions, outdoor weathering produced relatively small changes in color, Durometer hardness, or tensile properties compared with time passage. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  4. Hardness and Microstructure of Binary and Ternary Nitinol Compounds

    Science.gov (United States)

    Stanford, Malcolm K.

    2016-01-01

    The hardness and microstructure of twenty-six binary and ternary Nitinol (nickel titanium, nickel titanium hafnium, nickel titanium zirconium and nickel titanium tantalum) compounds were studied. A small (50g) ingot of each compound was produced by vacuum arc remelting. Each ingot was homogenized in vacuum for 48 hr followed by furnace cooling. Specimens from the ingots were then heat treated at 800, 900, 1000 or 1100 degree C for 2 hr followed by water quenching. The hardness and microstructure of each specimen was compared to the baseline material (55-Nitinol, 55 at.% nickel - 45 at.% titanium, after heat treatment at 900 degC). The results show that eleven of the studied compounds had higher hardness values than the baseline material. Moreover, twelve of the studied compounds had measured hardness values greater 600HV at heat treatments from 800 to 900 degree C.

  5. Analysis of surface hardness of artificially aged resin composites

    Directory of Open Access Journals (Sweden)

    Denise Cremonezzi Tornavoi

    2012-02-01

    Full Text Available This study evaluated the effect of artificially accelerated aging (AAA on the surface hardness of eight composite resins: Filtek Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma, and Filtek Z100. Sixteen specimens were made from the test piece of each material, using an 8.0 × 2.0 mm teflon matrix. After 24 hours, eight specimens from each material were submitted to three surface hardness readings using a Shimadzu Microhardness Tester for 5 seconds at a load of 50 gf. The other eight specimens remained in the artificially accelerated aging machine for 382 hours and were submitted to the same surface hardness analysis. The means of each test specimen were submitted to the Kolmogorov-Smirnov test (p > 0.05, ANOVA and Tukey test (p < 0.05. With regard to hardness (F = 86.74, p < 0.0001 the analysis showed significant differences among the resin composite brands. But aging did not influence the hardness of any of the resin composites (F = 0.39, p = 0.53. In this study, there was interaction between the resin composite brand and the aging factors (F = 4.51, p < 0.0002. It was concluded that notwithstanding the type of resin, AAA did not influence surface hardness. However, with regard to hardness there was a significant difference among the resin brands.

  6. Catalytic Hydrodehalogenation of Some Organic Halides by Hydrogen Transfer from Lithium Formate in the Presence of Ruthenium and Rhodium Complexes

    OpenAIRE

    Marčec, Radovan

    1990-01-01

    Organic halides react with lithium formate in the presence of ruthenium and rhodium phosphine complexes as homogeneous catalysts in refluxing dioxane producing the corresponding deha- logenated compounds in moderate yields.

  7. Ruthenium-catalyzed aerobic oxidative decarboxylation of amino acids: a green, zero-waste route to biobased nitriles.

    Science.gov (United States)

    Claes, Laurens; Verduyckt, Jasper; Stassen, Ivo; Lagrain, Bert; De Vos, Dirk E

    2015-04-18

    Oxidative decarboxylation of amino acids into nitriles was performed using molecular oxygen as terminal oxidant and a heterogeneous ruthenium hydroxide-based catalyst. A range of amino acids was oxidized in very good yield, using water as the solvent.

  8. Catalytic Properties of Alumina-Supported Ruthenium, Platinum, and Cobalt Nanoparticles towards the Oxidation of Cyclohexane to Cyclohexanol and Cyclohexanone

    Directory of Open Access Journals (Sweden)

    Ilhem Rekkab-Hammoumraoui

    2018-01-01

    Full Text Available A series of metal-loaded (Ru, Pt, Co alumina catalysts were evaluated for the catalytic oxidation of cyclohexane using tertbutylhydroperoxide (TBHP as oxidant and acetonitrile or acetic acid as solvent. These materials were prepared by the impregnation method and then characterized by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES, H2 chemisorption, Fourier Transformed Infrared Spectroscopy (FTIR, High-Resolution Transmission Electron Microscopy (HRTEM, and X-ray Diffraction (XRD. All the prepared materials acted as efficient catalysts. Among them, Ru/Al2O3 was found to have the best catalytic activity with enhanced cyclohexane conversion of 36 %, selectivity to cyclohexanol and cyclohexanone of 96 % (57.6 mmol, and cyclohexane turnover frequency (TOF of 288 h-1. Copyright © 2018 BCREC Group. All rights reserved Received: 26th May 2017; Revised: 17th July 2017; Accepted: 18th July 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018 How to Cite: Rekkab-Hammoumraoui, I., Choukchou-Braham, A. (2018. Catalytic Properties of Alumina-Supported Ruthenium, Platinum, and Cobalt Nanoparticles towards the Oxidation of Cyclohexane to Cyclohexanol and Cyclohexanone. Bulletin of Chemical Reaction Engineering & Catalysis, 13(1: 24-36 (doi:10.9767/bcrec.13.1.1226.24-35

  9. Application of hard coatings for blanking and piercing tools

    DEFF Research Database (Denmark)

    Podgornik, B.; Zajec, B.; Bay, Niels

    2011-01-01

    The aim of the present investigation was to examine the possibility of reducing lubrication and replacing expensive tungsten carbide material in blanking/piercing through introduction of hard tool coatings. Results show that hard PVD coatings can be successfully used in blanking/piercing...... critical value under dry friction conditions and leads to tool failure. Therefore, at present oxidation and temperature resistant hard coatings can give improved wear resistance of stamping tools, but elimination of lubricants in blanking and piercing processes is still not feasible....

  10. Laser thermographic technologies for hard copy recording

    Science.gov (United States)

    Bessmel'tsev, Viktor P.; Baev, Sergej G.

    1995-04-01

    Methods of hard copies recording based on thermal interaction of the beam from CO2 or YAG lasers with various kinds of films on any substrates have been developed. The recording processes are single-step and require no additional development. Among them are: (1) Laser thermodestruction of thin mask layers or of a material surface on any kinds of substrates. (2) Laser thermochemical reactions of thermal decomposition of metal salts in solid state phase on a surface of various hygroscopic substrates. The laser recording devices using the methods, described above have been developed and are manufactured now; they allow one to record hard copies with a size of up to 27 X 31 inches, a resolution of 4000 dpi.

  11. Fiscal 1998 regional consortium R and D project (Regional consortium field). Report on R and D of production technology of hybrid-type biocompatible hard tissue replacing materials (1st fiscal year); 1998 nendo chiiki konsoshiamu kenkyu kaihatsu jigyo. Chiiki konsoshiamu bun'ya (hybrid gata seitai yugo kinosei kososhiki daitai sozai seizo gijutsu no kenkyu kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    This project aims at development of high-strength high- biocompatible {beta}-type Ti alloy with lower modulli of elasticity composed of non-toxic elements, phosphate calcium ceramics for improving the biocompatibility and coating technology, and establishment of production technology of hybrid-type biocompatible hard tissue replacing materials. In fiscal 1998, the project promoted the following: Design of high-biocompatible {beta}-type Ti alloy materials, development of thermomechanical treatment for improving dynamic characteristics of such alloy, survey on practical melting and casting technologies and dental precision casting process, evaluation of the biocompatibility of the alloy by cytotoxicity, selection of tools for precision machining and surface finishing, control of contents, orientation and precipitation of biocompatible crystals such as {beta}- Ca(PO{sub 3}){sub 2} fibers for further improvement of the biocompatibility. This paper also outlines the survey results on the market needs, market size and market share for the feasibility of these materials. (NEDO)

  12. Estimating Hardness from the USDC Tool-Bit Temperature Rise

    Science.gov (United States)

    Bar-Cohen, Yoseph; Sherrit, Stewart

    2008-01-01

    A method of real-time quantification of the hardness of a rock or similar material involves measurement of the temperature, as a function of time, of the tool bit of an ultrasonic/sonic drill corer (USDC) that is being used to drill into the material. The method is based on the idea that, other things being about equal, the rate of rise of temperature and the maximum temperature reached during drilling increase with the hardness of the drilled material. In this method, the temperature is measured by means of a thermocouple embedded in the USDC tool bit near the drilling tip. The hardness of the drilled material can then be determined through correlation of the temperature-rise-versus-time data with time-dependent temperature rises determined in finite-element simulations of, and/or experiments on, drilling at various known rates of advance or known power levels through materials of known hardness. The figure presents an example of empirical temperature-versus-time data for a particular 3.6-mm USDC bit, driven at an average power somewhat below 40 W, drilling through materials of various hardness levels. The temperature readings from within a USDC tool bit can also be used for purposes other than estimating the hardness of the drilled material. For example, they can be especially useful as feedback to control the driving power to prevent thermal damage to the drilled material, the drill bit, or both. In the case of drilling through ice, the temperature readings could be used as a guide to maintaining sufficient drive power to prevent jamming of the drill by preventing refreezing of melted ice in contact with the drill.

  13. Hardness Changes of Tissue Conditioners in Various Storage Media: An in Vitro Study.

    Science.gov (United States)

    Ntounis, Athanasios; Kamposiora, Phophi; Papavasiliou, George; Divaris, Kimon; Zinelis, Spiros

    2015-03-01

    The aim of the present study was to evaluate the effects of storage media on the longitudinal hardness changes of tissue conditioning materials. Four tissue-conditioning materials were used for fabrication of 80 disc-shaped specimens and divided in four groups, stored in four storage media. The specimens underwent artificial ageing corresponding to 30 nights of extra-oral storage. Hardness measurements were obtained at nine intervals between 8 and 240 hours after specimen fabrication. To test the effects of storage media on hardness we employed multivariate modelling (Bonferroni correction; α = 0.05). The materials exhibited varying hardness changes, most pronounced when stored in ambient air.

  14. Structural characterization of mono-ruthenium substituted Keggin-type silicotungstates.

    Science.gov (United States)

    Sadakane, Masahiro; Tsukuma, Daisuke; Dickman, Michael H; Bassil, Bassem; Kortz, Ulrich; Higashijima, Michio; Ueda, Wataru

    2006-09-21

    We have synthesized the mono-ruthenium substituted Keggin-type silicotungstate [SiW(11)O(39)Ru(III)(H(2)O)](5-) (1a) by reaction of the mono-lacunary silicotungstate precursor [SiW(11)O(39)](8-) with Ru(acac)(3) under hydrothermal conditions and isolated as the caesium salt Cs(5)[SiW(11)O(39)Ru(III)(H(2)O)] (1). The DMSO-coordinated complex [SiW(11)O(39)Ru(III)(DMSO)](5-) (2a) was prepared by reaction of 1a with DMSO in aqueous solution at 353 K and isolated as the caesium-potassium mixed salt Cs(4.9)K(0.1)[SiW(11)O(39)Ru(III)(DMSO)] (2). Both compounds 1 and 2 were characterized by single-crystal X-ray structure analysis, powder X-ray structure analysis, UV-Vis spectroscopy, cyclic voltammetry, IR-spectroscopy and elemental analysis. 1 crystallized in the tetragonal space group P4(2)/ncm with a = 20.9299(4), c = 10.3603(4) Angstrom, Z = 4. The ruthenium atom in the Keggin unit could not be distinguished from the tungsten due to disorder. The structural analysis of 2 (monoclinic, P2(1)/c, a = 13.5850(4), b = 20.2764(7), c = 18.1326(4) Angstrom, beta = 90.8730(10) degrees , Z = 4) successfully revealed that the incorporated ruthenium atom is coordinated by DMSO through a Ru-S bond. Polyanion 2a represents the first mono-substituted Keggin ion in which the ruthenium center is not crystallographically disordered. UV-Vis spectroscopy combined with controlled potential electrolysis confirmed that the incorporated rutheniums in 1 and 2 have a valence state of +3. The IR spectra of both 1 and 2 were very similar. All these data indicate that 1 synthesized by reaction of the mono-lacunary silicotungstate K(8)[SiW(11)O(39)] with Ru(acac)(3) under hydrothermal conditions is truly the mono-ruthenium substituted Keggin-type silicotungstate.

  15. Dependence of Hardness of Silicate Glasses on Composition and Thermal History

    DEFF Research Database (Denmark)

    Jensen, Martin; Smedskjær, Morten Mattrup; Yue, Yuanzheng

    The prediction of hardness is possible for crystalline materials, but so far not possible for glasses. In this work, several important factors that should be used for predicting the hardness of glasses are discussed. To do so, we have studied the influences of thermal history and chemical...... composition on hardness of silicate glasses. E-glasses of different compositions are subjected to various degrees of annealing to obtain various fictive temperatures in the glasses. It is found that hardness decreases with the fictive temperature. Addition of Na2O to a SiO2-Al2O3-Na2O glass system causes...... a decrease in hardness. However, hardness cannot solely be determined from the degree of polymerisation of the glass network. It is also determined by the effect of ionic radius on hardness. However, this effect has opposite trend for alkali and alkaline earth ions. The hardness increases with ionic radius...

  16. Comparison of time-dependent changes in the surface hardness of different composite resins

    Science.gov (United States)

    Ozcan, Suat; Yikilgan, Ihsan; Uctasli, Mine Betul; Bala, Oya; Kurklu, Zeliha Gonca Bek

    2013-01-01

    Objective: The aim of this study was to evaluate the change in surface hardness of silorane-based composite resin (Filtek Silorane) in time and compare the results with the surface hardness of two methacrylate-based resins (Filtek Supreme and Majesty Posterior). Materials and Methods: From each composite material, 18 wheel-shaped samples (5-mm diameter and 2-mm depth) were prepared. Top and bottom surface hardness of these samples was measured using a Vicker's hardness tester. The samples were then stored at 37°C and 100% humidity. After 24 h and 7, 30 and 90 days, the top and bottom surface hardness of the samples was measured. In each measurement, the rate between the hardness of the top and bottom surfaces were recorded as the hardness rate. Statistical analysis was performed by one-way analysis of variance, multiple comparisons by Tukey's test and binary comparisons by t-test with a significance level of P = 0.05. Results: The highest hardness values were obtained from each two surfaces of Majesty Posterior and the lowest from Filtek Silorane. Both the top and bottom surface hardness of the methacrylate based composite resins was high and there was a statistically significant difference between the top and bottom hardness values of only the silorane-based composite, Filtek Silorane (P hardness values of all test groups increased after 24 h (P hardness ratio, the use of incremental technic during application is more important than methacrylate based composites. PMID:24966724

  17. Tribological characterization of thin, hard coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hogmark, S. (Uppsala Univ., Dept. of Technology, Materials Science Div. (Sweden)); Hedenqvist, P. (Uppsala Univ., Dept. of Technology, Materials Science Div. (Sweden))

    1994-12-01

    The use of thin, hard coatings in tribological applications has become more widespread. Thus the need to fully understand the relationships between the intrinsic properties of the coating, the properties of the coating/substrate composite and the tribological performance of the composite in different tribological systems has become more pressing. The present paper contributes to this effort by presenting and discussing the use of a selected number of physical and mechanical tests to obtain a general characterization of the tribological properties of a coated material: its tribological profile. The tribological tests include dry sliding wear, solid particle erosion and microabrasion. Even if the emphasis of the present paper is put on tribological characterization of thin, hard coatings, some of the current techniques frequently employed to characterize some of the more general properties of a coating, e.g. thickness, hardness, adhesion, residual stress state, etc., are treated. Examples from tribology profile determination and general characterization are collected from PVD and CVD coating systems. (orig.)

  18. Carbon deposition in the Bosch process with ruthenium and ruthenium-iron alloy catalysts. M.S. Thesis. Final Report, Jan. 1981 - Jul. 1982

    Science.gov (United States)

    Manning, M. P.; Reid, R. C.; Sophonpanich, C.

    1982-01-01

    The effectiveness of ruthenium and the alloys 50Ru50Fe and 33Ru67Fe as alternatives to iron, nickel, and cobalt catalysts in recovering oxygen from metabolic carbon dioxide was investigated. Carbon deposition boundaries over the unsupported alloys are reported. Experiments were also carried out over 50Ru50Fe and 97Ru3Fe3 catalysts supported on gamma-alumina to determine their performance in the synthesis of low molecular weight olefins. High production of ethylene and propylene would be beneficial for an improvement of an overall Bosch process, as a gas phase containing high olefin content would enhance carbon deposition in a Bosch reactor.

  19. Electrochemical characterization of ruthenium oxide on carbon paste electrodes in acid system

    Directory of Open Access Journals (Sweden)

    O. Martinez-Alvarez

    2009-12-01

    Full Text Available A comparative study of the electrochemical behavior of ruthenium in the electrolytic system 10-2 M RuCl3 /1 M HClO4 at pH=1 was carried out using carbon paste electrodes prepared with carbon black(nanostructurated. Measurements of absorbance in the region of visible spectrum showed that the electroactive species is an oxy aquocomplex. Studies of cyclic voltammetry of reversed potentials (Eλ allowed for the description of the oxidation processes involved. The oxidation process explained the electrochemical formation of a ruthenium oxide (RuO4 which appeared with a defined potential value. This permitted its electrochemical growth on the paste electrodes. Capacitive behavior of this oxide in the system 1 M HClO4 was also characterized and its specific capacitance (F/g was evaluated applying a current pulse. The obtained specific capacitance is of 120 Fg-1.

  20. Ruthenium-containing P450 inhibitors for dual enzyme inhibition and DNA damage.

    Science.gov (United States)

    Zamora, Ana; Denning, Catherine A; Heidary, David K; Wachter, Erin; Nease, Leona A; Ruiz, José; Glazer, Edith C

    2017-02-14

    Cytochrome P450s are key players in drug metabolism, and overexpression in tumors is associated with significant resistance to many medicinal agents. Consequently, inhibition of P450s could serve as a strategy to restore drug efficacy. However, the widespread expression of P450s throughout the human body and the critical roles they play in various biosynthetic pathways motivates the development of P450 inhibitors capable of controlled local administration. Ruthenium complexes containing P450 inhibitors as ligands were synthesized in order to develop pro-drugs that can be triggered to release the inhibitors in a spatially and temporally controlled fashion. Upon light activation the compounds release ligands that directly bind and inhibit P450 enzymes, while the ruthenium center is able to directly damage DNA.

  1. Studies of dissolution solutions of ruthenium metal, oxide and mixed compounds in nitric acid

    Energy Technology Data Exchange (ETDEWEB)

    Mousset, F.; Eysseric, C.; Bedioui, F

    2004-07-01

    Ruthenium is one of the fission products generated by irradiated nuclear fuel. It is present throughout all the steps of nuclear fuel reprocessing-particularly during extraction-and requires special attention due to its complex chemistry and high {beta}{gamma} activity. An innovative electro-volatilization process is now being developed to take advantage of the volatility of RuO{sub 4} in order to eliminate it at the head end of the Purex process and thus reduce the number of extraction cycles. Although the process operates successfully with synthetic nitrato-RuNO{sup 3+} solutions, difficulties have been encountered in extrapolating it to real-like dissolution solutions. In order to better approximate the chemical forms of ruthenium found in fuel dissolution solutions, kinetic and speciation studies on dissolved species were undertaken with RuO{sub 2},xH{sub 2}O and Ru{sup 0} in nitric acid media. (authors)

  2. Ruthenium-Catalyzed Transformations of Alcohols: Mechanistic Investigations and Methodology Development

    DEFF Research Database (Denmark)

    Makarov, Ilya; Madsen, Robert; Fristrup, Peter

    The mechanism of the ruthenium-catalyzed dehydrogenative synthesis of amides from alcohols and amines was studied in detail by employing the combination of experimental and theoretical techniques. The Hammett study revealed that a small positive charge is formed at the benzylic position in the tr......The mechanism of the ruthenium-catalyzed dehydrogenative synthesis of amides from alcohols and amines was studied in detail by employing the combination of experimental and theoretical techniques. The Hammett study revealed that a small positive charge is formed at the benzylic position....... It was shown that tin-Beta zeolite was only capable of producing crotonaldehyde in low yields. Several other heterogeneous catalysts were tested (Al-Beta, Ti-Beta, Sn-MCM-41, ts-1) but none of them demonstrated substantially higher activity in the studied transformation....

  3. Large-scale ruthenium- and enzyme-catalyzed dynamic kinetic resolution of (rac-1-phenylethanol

    Directory of Open Access Journals (Sweden)

    Bäckvall Jan-E

    2007-12-01

    Full Text Available Abstract The scale-up of the ruthenium- and enzyme-catalyzed dynamic kinetic resolution (DKR of (rac-1-phenylethanol (2 is addressed. The immobilized lipase Candida antarctica lipase B (CALB was employed for the resolution, which shows high enantioselectivity in the transesterification. The ruthenium catalyst used, (η 5-C5Ph5RuCl(CO2 1, was shown to possess very high reactivity in the "in situ" redox racemization of 1-phenylethanol (2 in the presence of the immobilized enzyme, and could be used in 0.05 mol% with high efficiency. Commercially available isopropenyl acetate was employed as acylating agent in the lipase-catalyzed transesterifications, which makes the purification of the product very easy. In a successful large-scale DKR of 2, with 0.05 mol% of 1, (R-1-phenylethanol acetate (3 was obtained in 159 g (97% yield in excellent enantiomeric excess (99.8% ee.

  4. Effect of solvent on Se-modified ruthenium/carbon catalyst for oxygen reduction

    Directory of Open Access Journals (Sweden)

    Chuanxiang Zhang

    2014-12-01

    Full Text Available Se-modified ruthenium supporting on carbon (Sex–Ru/C electrocatalyst was prepared by solvothermal one-step synthesis method. The reaction mechanism was revealed after discussing impact of different solvents (i-propanol and EG in solvotermal reaction. The result showed that the grain size of Se-modified ruthenium electrocatalyst was as small as 1 to 3 nm and highly dispersed on carbon surface. X-ray photoelectron spectroscopy (XPS presented that selenium mainly existed in the catalyst in the form of elemental selenium and selenium oxides when the solvent was EG and i-propanol, respectively. The oxygen reduction reaction (ORR performance was improved by appearance of selenium oxides.

  5. Electro-volatilization of ruthenium in nitric medium: influences of ruthenium species nature and models solutions composition; Electro-volatilisation du ruthenium en milieu nitrique: influence de la nature des formes chimiques du ruthenium et de la composition des solutions modeles de dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Mousset, F

    2004-12-15

    Ruthenium is one of the fission products in the reprocessing of irradiated fuels that requires a specific processing management. Its elimination, upstream by the PUREX process, has been considered. A process, called electro-volatilization, which take advantage of the RuO{sub 4} volatility, has been optimised in the present study. It consists in a continuous electrolysis of ruthenium solutions in order to generate RuO{sub 4} species that is volatilized and easily trapped. This process goes to satisfying ruthenium elimination yields with RuNO(NO{sub 3}){sub 3}(H{sub 2}O){sub 2} synthetic solutions but not with fuel dissolution solutions. Consequently, this work consisted in the speciation studies of dissolved ruthenium species were carried out by simulating fuel solutions produced by hot acid attack of several ruthenium compounds (Ru(0), RuO{sub 2},xH{sub 2}O, polymetallic alloy). In parallel with dissolution kinetic studies, the determination of dissolved species was performed using voltammetry, spectrometry and spectro-electrochemistry. The results showed the co-existence of Ru(IV) and RuNO(NO{sub 2}){sub 2}(H{sub 2}O){sub 3}. Although these species are different from synthetic RuNO(NO{sub 3}){sub 3}(H{sub 2}O){sub 2}, their electro-oxidation behaviour are similar. The electro-volatilization tests of these dissolution solutions yielded to comparable results as the synthetic RuNO(NO{sub 3}){sub 3}(H{sub 2}O){sub 2} solutions. Then, complexity increase of models solutions was performed by in-situ generation of nitrous acid during ruthenium dissolution. Nitrous acid showed a catalytic effect on ruthenium dissolution. Its presence goes to quasi exclusively RuNO(NO{sub 2}){sub 2}(H{sub 2}O){sub 3} species. It is also responsible of the strong n-bond formation between Ru{sup 2+} and NO{sup +}. In addition, it has been shown that its reducing action on RuO{sub 4} hinders the electro-volatilization process. Mn{sup 2+} and Ce{sup 3+} cations also reveal, but to a lesser

  6. Influence of Hard Tool Coatings on Process of Stamping

    DEFF Research Database (Denmark)

    Zajec, Bostjan; Podgornik, Bojan; Bay, Niels

    2007-01-01

    of tool life can be achieved by proper selection of tool materials and possible coatings. In mass production the tools are usually made of WC, which however, results in expensive tools and long time of delivery. The aim of the present investigation was to determine the influence of different tool...... materials and possible hard coatings as alternative tool materials. For this purpose the blanking/punching process was first analyzed by a numerical model and based on the results four different tool materials and three hard coatings were included in the investigation and tested in a model test rig as well...... as in a real blanking/punching operation. The tool materials included were WC, BRM, ASP and S390. These materials were tested uncoated as well as coated, with the commercial coatings: Balinit B, Balinit Alcrona and Balinit Hardlube, respectively....

  7. Radiation Hardness Assurance for Space Systems

    Science.gov (United States)

    Poivey, Christian; Day, John H. (Technical Monitor)

    2002-01-01

    The space radiation environment can lead to extremely harsh operating conditions for on-board electronic box and systems. The characteristics of the radiation environment are highly dependent on the type of mission (date, duration and orbit). Radiation accelerates the aging of the electronic parts and material and can lead to a degradation of electrical performance; it can also create transient phenomena on parts. Such damage at the part level can induce damage or functional failure at electronic box, subsystem, and system levels. A rigorous methodology is needed to ensure that the radiation environment does not compromise the functionality and performance of the electronics during the system life. This methodology is called hardness assurance. It consists of those activities undertaken to ensure that the electronic piece parts placed in the space system perform to their design specifications after exposure to the space environment. It deals with system requirements, environmental definitions, part selection, part testing, shielding and radiation tolerant design. All these elements should play together in order to produce a system tolerant to.the radiation environment. An overview of the different steps of a space system hardness assurance program is given in section 2. In order to define the mission radiation specifications and compare these requirements to radiation test data, a detailed knowledge of the space environment and the corresponding electronic device failure mechanisms is required. The presentation by J. Mazur deals with the Earth space radiation environment as well as the internal environment of a spacecraft. The presentation by J. Schwank deals with ionization effects, and the presentation by T. Weatherford deals with Single particle Event Phenomena (SEP) in semiconductor devices and microcircuits. These three presentations provide more detailed background to complement the sections 3 and 4. Part selection and categorization are discussed in section

  8. Hard-phase engineering in hard/soft nanocomposite magnets

    Science.gov (United States)

    Poudyal, Narayan; Rong, Chuanbing; Vuong Nguyen, Van; Liu, J. Ping

    2014-03-01

    Bulk SmCo/Fe(Co) based hard/soft nanocomposite magnets with different hard phases (1:5, 2:17, 2:7 and 1:3 types) were fabricated by high-energy ball-milling followed by a warm compaction process. Microstructural studies revealed a homogeneous distribution of bcc-Fe(Co) phase in the matrix of hard magnetic Sm-Co phase with grain size ⩽20 nm after severe plastic deformation and compaction. The small grain size leads to effective inter-phase exchange coupling as shown by the single-phase-like demagnetization behavior with enhanced remanence and energy product. Among the different hard phases investigated, it was found that the Sm2Co7-based nanocomposites can incorporate a higher soft phase content, and thus a larger reduction in rare-earth content compared with the 2:17, 1:5 and 1:3 phase-based nanocomposite with similar properties. (BH)max up to 17.6 MGOe was obtained for isotropic Sm2Co7/FeCo nanocomposite magnets with 40 wt% of the soft phase which is about 300% higher than the single-phase counterpart prepared under the same conditions. The results show that hard-phase engineering in nanocomposite magnets is an alternative approach to fabrication of high-strength nanocomposite magnets with reduced rare-earth content.

  9. Development of a new class of ruthenium polypyridine photo-redox ...

    Indian Academy of Sciences (India)

    Administrator

    A new class of ruthenium terpyridine complexes incorporating imine functionalities,. [RuII/III/IV(trpy)(L)Cl] (L ... A significant shift in MLCT band energy has been observed depending on the field ... energy MLCT bands in the range 661–690 nm in EtOH-MeOH (4:1 v/v) at 77 K. The quantum yields of the complexes are found ...

  10. Improvements in iodine and ruthenium removal from advanced liquid processing system

    Energy Technology Data Exchange (ETDEWEB)

    Skibo, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-27

    SRNL has considerable experience in designing, engineering, and operating systems for removing iodine-129 (I-129) and ruthenium-106 (Ru-106) from waste streams that are directly analogous to the Advanced Liquid Processing System (ALPS) waste streams. SRNL proposes to provide the technical background and design and engineering support for an improved I-129 and Ru-106 removal system for application to ALPS on the Fukushima Daiichi Nuclear Power Station (NPS).

  11. Ruthenium-catalysed decomposition of formic acid: Fuel cell and catalytic applications

    KAUST Repository

    Piola, Lorenzo

    2017-08-08

    The decomposition of formic acid into H2 and CO2 was successfully performed using a ruthenium hydride catalyst, without any concomitant CO evolution. The reaction mechanism is investigated by means of density functional theory calculations (DFT). The generated H2 was further exploited in a fuel cell to produce electricity. The catalytic hydrogenation of conjugated olefins, using this dihydrogen generation procedure, is also reported.

  12. E- and Z-Selective Transfer Semihydrogenation of Alkynes Catalyzed by Standard Ruthenium Olefin Metathesis Catalysts.

    Science.gov (United States)

    Kusy, Rafał; Grela, Karol

    2016-12-02

    Selective transfer semihydrogenation of alkynes to yield alkenes was achieved with commercial first and second generation Hoveyda-Grubbs catalysts and formic acid as a hydrogen donor. This catalytic system is distinguished by its selectivity and compatibility with many functional groups (halogens, cyano, nitro, sulfide, alkenes). The metathetic activity of the ruthenium catalysts may be utilized in tandem sequences of olefin metathesis plus alkyne reduction.

  13. Ruthenium-Catalyzed Olefin Metathesis after Tetra-n-butylammonium Fluoride-Mediated Desilylation

    Science.gov (United States)

    Osman, Sami

    2012-01-01

    One-pot procedures expedite organic synthesis but pose challenges in that many reagents must be compatible with each other. We discovered that the presence of nBu4NF hindered rutheniumcatalyzed olefin metathesis when nBu4NF-mediated desilylation and olefin metathesis were performed in one pot. This problem could be solved by the addition of (TMS)2O to remove fluoride anions in order to facilitate the ruthenium-catalyzed olefin metathesis. PMID:23269856

  14. Transferrin serves as a mediator to deliver organometallic ruthenium(II) anticancer complexes into cells.

    Science.gov (United States)

    Guo, Wei; Zheng, Wei; Luo, Qun; Li, Xianchan; Zhao, Yao; Xiong, Shaoxiang; Wang, Fuyi

    2013-05-06

    We report herein a systematic study on interactions of organometallic ruthenium(II) anticancer complex [(η(6)-arene)Ru(en)Cl](+) (arene = p-cymene (1) or biphenyl (2), en = ethylenediamine) with human transferrin (hTf) and the effects of the hTf-ligation on the bioavailability of these complexes with cisplatin as a reference. Incubated with a 5-fold excess of complex 1, 2, or cisplatin, 1 mol of diferric hTf (holo-hTf) attached 0.62 mol of 1, 1.01 mol of 2, or 2.14 mol of cisplatin. Mass spectrometry revealed that both ruthenium complexes coordinated to N-donors His242, His273, His578, and His606, whereas cisplatin bound to O donors Tyr136 and Tyr317 and S-donor Met256 in addition to His273 and His578 on the surface of both apo- and holo-hTf. Moreover, cisplatin could bind to Thr457 within the C-lobe iron binding cleft of apo-hTf. Neither ruthenium nor platinum binding interfered with the recognition of holo-hTf by the transferrin receptor (TfR). The ruthenated/platinated holo-hTf complexes could be internalized via TfR-mediated endocytosis at a similar rate to that of holo-hTf itself. Moreover, the binding to holo-hTf well preserved the bioavailability of the ruthenium complexes, and the hTf-bound 1 and 2 showed a similar cytotoxicity toward the human breast cancer cell line MCF-7 to those of the complexes themselves. However, the conjugation with holo-hTf significantly reduced the cellular uptake of cisplatin and the amount of platinated DNA adducts formed intracellularly, leading to dramatic reduction of cisplatin cytotoxicity toward MCF-7. These findings suggest that hTf can serve as a mediator for the targeting delivery of Ru(arene) anticancer complexes while deactivating cisplatin.

  15. Cytogenotoxic effects of two potential anticancer Ruthenium(III Schiff Bases complexes

    Directory of Open Access Journals (Sweden)

    Izet Eminovic

    2016-10-01

    Full Text Available Introduction: Treatment of cancer has been subject of great interest. Researchers are continuously searching for new medicines. In this sense, ruthenium complexes have big potential. Some evidences suggest that ruthenium compounds possess anticancer activities. We synthesized two recently published ruthenium(III complexes with bidentate O,N and tridentate O,O,N Schiff bases derived from 5-substituted salicylaldehyde and aminophenol or anilineare. These compounds showed affinity for binding to the DNA molecule, however, insufficient data are available regarding their possible toxic effects on biological systems.Methods: In the present study we evaluated genotoxic, cytotoxic, and cytostatic effects of Na[RuCl2(L12] and Na[Ru(L22], using the Allium cepa assay.Results: Different toxic effects were observed depending on the substance, tested concentration, and endpoint measured. In general, the tested compounds significantly lowered the root growth and mitotic index values as compared to the control group. Additionally, a wide range of abnormal mitotic stages, both clastogenic and non-clastogenic were observed in the treated cells. Na[RuCl2(L12] significantly increased the frequency of sticky metaphases, chromosome bridges, micronuclei, impaired chromosome segregation, as well as number of apoptotic and necrotic cells over the controls. In contrast, Na[Ru(L22] did not show significant evidence of genotoxicity with regard to chromosome aberrations and micronuclei, however, significant differences were detected in the number of apoptotic and necrotic cells when the highest concentration was applied.Conclusions: In this study we demonstrated antiproliferative effects of Na[RuCl2(L12] and Na[Ru(L22]. At clinical level, these results could be interesting for further studies on anticancer potential of the ruthenium(III complexes using animal models.

  16. Ruthenium(II) pincer complexes with oxazoline arms for efficient transfer hydrogenation reactions

    KAUST Repository

    Chen, Tao

    2012-08-01

    Well-defined P NN CN pincer ruthenium complexes bearing both strong phosphine and weak oxazoline donors were developed. These easily accessible complexes exhibit significantly better catalytic activity in transfer hydrogenation of ketones compared to their PN 3P analogs. These reactions proceed under mild and base-free conditions via protonation- deprotonation of the \\'NH\\' group in the aromatization-dearomatization process. © 2012 Elsevier Ltd. All rights reserved.

  17. Interaction and reactivity of nitric oxide and carbon monoxide on ruthenium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Quick, E.E.

    1980-03-01

    A multifaceted investigation of the reduction of nitric oxide by carbon monoxide using a ruthenium (102) single crystal catalyst in the pressure range 10/sup -3/ to 10 Torr and temperature range of 300 to 475/sup 0/C has been undertaken. Kinetic and isotopic results indicate that the reaction products CO/sub 2/ and N/sub 2/ were produced via two reaction mechanisms. Using a reducing gas mixture (low P/sub NO//P/sub CO/ ratio) a two site mechanism was operative involving NO dissociation. The carbon monoxide kinetic order varied from +1 to -3 and the nitric oxide order varied from +1 to 0. The catalyst under these conditions was determined to be metallic ruthenium with oxygen bonded within the first surface layer. The oxygen was unreactive and formed a (1 x 3)-0 LEED pattern. Under oxidizing conditions (high P/sub NO//P/sub CO/ ratio) the catalyst was ruthenium dioxide and the functional mechanism under these reaction conditions yielded a nitric oxide order of +2 to -4. Inclusion of a site poisoning mechanism under reducing conditions and an RuO/sub 2/ growth mechanism involving ruthenium cation transfer under oxidizing conditions into the kinetic rate laws led to an overall rate law which could be fit to the carbon monoxide and nitric oxide order plots. Using isotopically oxygen labelled reactants, it was observed that the three possible isotopes of carbon dioxide were produced. A ..gamma..-CO surface species is postulated as an intermediate in the exchange process. The reaction was observed to be initially surface structure insensitive and the reaction kinetics were derived using a Langmuir-Hinshelwood formalism.

  18. Ruthenium polypyridyl complexes relevant to the catalytic processes in artificial photosynthesis

    OpenAIRE

    Planas Roure, Nora

    2011-01-01

    Artificial photosynthesis seeks to functionally mimik the photosynthetic process carried out by nature, and combine the energy from the sun with water to obain a “solar” fuel like hydrogen. One of the strategies in the field, consists on a modular approach in which all the components needed are studied independently, in view of their future assembly in a final operative device. This thesis has been focused on the synthesis and characterization of a series of new mono and dinuclear ruthenium c...

  19. Structural Investigation in Solution of a series of five-Coordinate Bisphosphinoaryl Ruthenium(II) Complexes

    NARCIS (Netherlands)

    Koten, G. van; Dani, P.; Kink, G. van

    2000-01-01

    The structure of the ruthenium(II) complexes [RuCl{C6H2(CH2PPh2)2-2,6-R-4}(PPh3)] [R = H (1), Ph (2) or Br (3)] was investigated in solution using two-dimensional NMR techniques (1H-1H-, 13C-1H- and 31P-1H-correlation NMR spectroscopy and 1H NOESY). The 1H and 13C NMR spectra of the complexes 1-3

  20. Ruthenium-Catalyzed Regioselective C-H Bond Acetoxylation on Carbazole and Indole Frameworks.

    Science.gov (United States)

    Okada, Takeshi; Nobushige, Kazunori; Satoh, Tetsuya; Miura, Masahiro

    2016-03-04

    The regioselective C-H bond cleavage/C-O bond formation takes place smoothly upon treatment of 9-(pyridin-2-yl)carbazoles with acetic acid in the presence of a silver salt oxidant under ruthenium catalysis to afford the corresponding C1- and C8-diacetoxylated products. Under similar conditions, the acetoxylation of 2-aryl-1-(pyridin-2-yl)indoles as well as 1-aryl-7-azaindoles can also be conducted efficiently.

  1. Chemical bonding in hard boron-nitride multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Jankowski, A.F.; Hayes, J.P.

    1997-06-01

    The oxides and nitrides of boron show great potential for use as hard, wear resistant materials. However, large intrinsic stresses and poor adhesion often accompany the hard coatings as found for the cubic boron-nitride phase. These effects may be moderated for use of a layered structure. Alternate stiff layers of boron and compliant layers of nitride are formed by modulating the sputter gas composition during deposition of boron target. The B/BN thin films are characterized with transmission electronic microscope to evaluate the microstructure, nanoindentation to measure hardness and ex-ray absorption spectroscopy to determine chemical bonding. The effects of layer pair spacing on chemical bonding and hardness are evaluated for the B/BN films.

  2. Carboxylate-assisted C(sp³)-H activation in olefin metathesis-relevant ruthenium complexes.

    Science.gov (United States)

    Cannon, Jeffrey S; Zou, Lufeng; Liu, Peng; Lan, Yu; O'Leary, Daniel J; Houk, K N; Grubbs, Robert H

    2014-05-07

    The mechanism of C-H activation at metathesis-relevant ruthenium(II) benzylidene complexes was studied both experimentally and computationally. Synthesis of a ruthenium dicarboxylate at a low temperature allowed for direct observation of the C-H activation step, independent of the initial anionic ligand-exchange reactions. A first-order reaction supports an intramolecular concerted metalation-deprotonation mechanism with ΔG(‡)(298K) = 22.2 ± 0.1 kcal·mol(-1) for the parent N-adamantyl-N'-mesityl complex. An experimentally determined ΔS(‡) = -5.2 ± 2.6 eu supports a highly ordered transition state for carboxylate-assisted C(sp(3))-H activation. Experimental results, including measurement of a large primary kinetic isotope effect (k(H)/k(D) = 8.1 ± 1.7), agree closely with a computed six-membered carboxylate-assisted C-H activation mechanism where the deprotonating carboxylate adopts a pseudo-apical geometry, displacing the aryl ether chelate. The rate of cyclometalation was found to be influenced by both the electronics of the assisting carboxylate and the ruthenium ligand environment.

  3. Triazoloisoquinoline-Based/Ruthenium-Hybrid Sensitizer for Efficient Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Che-Lung Lee

    2013-01-01

    Full Text Available Triazoloisoquinoline-based organic dyestuffs were synthesized and used in the fabrication of dye-sensitized solar cells (DSSCs. After cosensitization with ruthenium complex, the triazoloisoquinoline-based organic dyestuffs overcame the deficiency of ruthenium dyestuff absorption in the blue part of the visible spectrum. This method also fills the blanks of ruthenium dyestuff sensitized TiO2 film and forms a compact insulating molecular layer due to the nature of small molecular organic dyestuffs. The incident photon-to-electron conversion efficiency of N719 at shorter wavelength regions is 49%. After addition of a triazoloisoquinoline-based dyestuff for co-sensitization, the IPCE at 350–500 nm increased significantly. This can be attributed to the increased photocurrent of the cells, which improves the dye-sensitized photoelectric conversion efficiency from 6.23% to 7.84%, and the overall conversion efficiency increased by about 26%. As a consequence, this low molecular weight organic dyestuff is a promising candidate as coadsorbent and cosensitizer for highly efficient dye-sensitized solar cells.

  4. Chromium and Ruthenium-Doped Zinc Oxide Thin Films for Propane Sensing Applications

    Directory of Open Access Journals (Sweden)

    Maximino Avendaño-Alejo

    2013-03-01

    Full Text Available Chromium and ruthenium-doped zinc oxide (ZnO:Cr and (ZnO:Ru thin solid films were deposited on soda-lime glass substrates by the sol-gel dip-coating method. A 0.6 M solution of zinc acetate dihydrate dissolved in 2-methoxyethanol and monoethanolamine was used as basic solution. Chromium (III acetylacetonate and Ruthenium (III trichloride were used as doping sources. The Ru incorporation and its distribution profile into the films were proved by the SIMS technique. The morphology and structure of the films were studied by SEM microscopy and X-ray diffraction measurements, respectively. The SEM images show porous surfaces covered by small grains with different grain size, depending on the doping element, and the immersions number into the doping solutions. The sensing properties of ZnO:Cr and ZnO:Ru films in a propane (C3H8 atmosphere, as a function of the immersions number in the doping solution, have been studied in the present work. The highest sensitivity values were obtained for films doped from five immersions, 5.8 and 900, for ZnO:Cr and ZnO:Ru films, respectively. In order to evidence the catalytic effect of the chromium (Cr and ruthenium (Ru, the sensing characteristics of undoped ZnO films are reported as well.

  5. Half-sandwich ruthenium(II) biotin conjugates as biological vectors to cancer cells.

    Science.gov (United States)

    Babak, Maria V; Plażuk, Damian; Meier, Samuel M; Arabshahi, Homayon John; Reynisson, Jóhannes; Rychlik, Błażej; Błauż, Andrzej; Szulc, Katarzyna; Hanif, Muhammad; Strobl, Sebastian; Roller, Alexander; Keppler, Bernhard K; Hartinger, Christian G

    2015-03-23

    Ruthenium(II)-arene complexes with biotin-containing ligands were prepared so that a novel drug delivery system based on tumor-specific vitamin-receptor mediated endocytosis could be developed. The complexes were characterized by spectroscopic methods and their in vitro anticancer activity in cancer cell lines with various levels of major biotin receptor (COLO205, HCT116 and SW620 cells) was tested in comparison with the ligands. In all cases, coordination of ruthenium resulted in significantly enhanced cytotoxicity. The affinity of Ru(II) -biotin complexes to avidin was investigated and was lower than that of unmodified biotin. Hill coefficients in the range 2.012-2.851 suggest strong positive cooperation between the complexes and avidin. To estimate the likelihood of binding to the biotin receptor/transporter, docking studies with avidin and streptavidin were conducted. These explain, to some extent, the in vitro anticancer activity results and support the conclusion that these novel half-sandwich ruthenium(II)-biotin conjugates may act as biological vectors to cancer cells, although no clear relationship between the cellular Ru content, the cytotoxicity, and the presence of the biotin moiety was observed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Synthesis, characterization and antibacterial studies of ruthenium(III) complexes derived from chitosan schiff base.

    Science.gov (United States)

    Vadivel, T; Dhamodaran, M

    2016-09-01

    Chitosan can be modified chemically by condensation reaction of deacetylated chitosan with aldehyde in homogeneous phase. This condensation is carried by primary amine (NH2) with aldehyde (CHO) to form corresponding schiff base. The chitosan biopolymer schiff base derivatives are synthesized with substituted aldehydes namely 4-hydroxy-3-methoxy benzaldehyde, 2-hydroxy benzaldehyde, and 2-hydroxy-3-methoxy benzaldehyde, becomes a complexing agent or ligand. The Ruthenium(III) complexes were obtained by complexation of Ruthenium with schiff base ligands and this product exhibits as an excellent solubility and more biocompatibility. The novel series of schiff base Ruthenium(III) complexes are characterized by Elemental analysis, FT-IR spectroscopy, and Thermo-gravimetric analysis (TGA). The synthesized complexes have been subjected to antibacterial study. The antibacterial results indicated that the antibacterial activity of the complexes were more effective against Gram positive and Gram negative pathogenic bacteria. These findings are giving suitable support for developing new antibacterial agent and expand our scope for applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. C-H Bond Activation/Arylation Catalyzed by Arene-Ruthenium-Aniline Complexes in Water.

    Science.gov (United States)

    Binnani, Chinky; Tyagi, Deepika; Rai, Rohit K; Mobin, Shaikh M; Singh, Sanjay K

    2016-11-07

    Water-soluble arene-ruthenium complexes coordinated with readily available aniline-based ligands were successfully employed as highly active catalysts in the C-H bond activation and arylation of 2-phenylpyridine with aryl halides in water. A variety of (hetero)aryl halides were also used for the ortho-C-H bond arylation of 2-phenylpyridine to afford the corresponding ortho- monoarylated products as major products in moderate to good yields. Our investigations, including time-scaled NMR spectroscopy and mass spectrometry studies, evidenced that the coordinating aniline-based ligands, having varying electronic and steric properties, had a significant influence on the catalytic activity of the resulting arene-ruthenium-aniline-based complexes. Moreover, mass spectrometry identification of the cycloruthenated species, {(η6 -arene)Ru(κ2 -C,N-phenylpyridine)}+ , and several ligand-coordinated cycloruthenated species, such as [(η6 -arene)Ru(4-methylaniline)(κ2 -C,N-phenylpyridine)]+ , found during the reaction of 2-phenylpyridine with the arene-ruthenium-aniline complexes further authenticated the crucial roles of these species in the observed highly active and tuned catalyst. At last, the structures of a few of the active catalysts were also confirmed by single-crystal X-ray diffraction studies. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Tailoring Ruthenium Exposure to Enhance the Performance of fcc Platinum@Ruthenium Core-Shell Electrocatalysts in the Oxygen Evolution Reaction

    KAUST Repository

    AlYami, Noktan Mohammed

    2016-05-17

    The catalytic properties of noble metal nanocrystals are a function of their size, structure, and surface composition. In particular, achieving high activity without sacrificing stability is essential for designing commercially viable catalysts. A major challenge in designing state-of-the-art Ru-based catalysts for the oxygen evolution reaction (OER), which is a key step in water splitting, is the poor stability and surface tailorability of these catalysts. In this study, we designed rapidly synthesizable size-controlled, morphology-selective, and surface-tailored platinum-ruthenium core-shell (Pt@Ru) and alloy (PtRu) nanocatalysts in a scalable continuous-flow reactor. These core-shell nanoparticles with atomically precise shells were produced in a single synthetic step with carbon monoxide as the reducing agent. By varying the metal precursor concentration, a dendritic or layer-by-layer ruthenium shell can be grown. The catalytic activities of the synthesized Pt@Ru and PtRu nanoparticles exhibit noticeably higher electrocatalytic activity in the OER compared to that of pure Pt and Ru nanoparticles. Promisingly, Pt@Ru nanocrystals with a ~2-3 atomic layer Ru cuboctahedral shell surpass conventional Ru nanoparticles in terms of both durability and activity.

  9. Using Organic Light-Emitting Electrochemical Thin-Film Devices to Teach Materials Science

    Science.gov (United States)

    Sevian, Hannah; Muller, Sean; Rudmann, Hartmut; Rubner, Michael F.

    2004-01-01

    Materials science can be taught by applying organic light-emitting electrochemical thin-film devices and in this method students were allowed to make a light-emitting device by spin coating a thin film containing ruthenium (II) complex ions onto a glass slide. Through this laboratory method students are provided with the opportunity to learn about…

  10. A sensitive quantum dots-based "OFF-ON" fluorescent sensor for ruthenium anticancer drugs and ctDNA.

    Science.gov (United States)

    Huang, Shan; Zhu, Fawei; Qiu, Hangna; Xiao, Qi; Zhou, Quan; Su, Wei; Hu, Baoqing

    2014-05-01

    In this contribution, a simple and sensitive fluorescent sensor for the determination of both the three ruthenium anticancer drugs (1 to 3) and calf thymus DNA (ctDNA) was established based on the CdTe quantum dots (QDs) fluorescence "OFF-ON" mode. Under the experimental conditions, the fluorescence of CdTe QDs can be effectively quenched by ruthenium anticancer drugs because of the surface binding of these drugs on CdTe QDs and the subsequent photoinduced electron transfer (PET) process from CdTe QDs to ruthenium anticancer drugs, which render the system into fluorescence "OFF" status. The system can then be "ON" after the addition of ctDNA which brought the restoration of CdTe QDs fluorescence intensity, since ruthenium anticancer drugs broke away from the surface of CdTe QDs and inserted into double helix structure of ctDNA. The fluorescence quenching effect of the CdTe QDs-ruthenium anticancer drugs systems was mainly concentration dependent, which could be used to detect three ruthenium anticancer drugs. The limits of detection were 5.5 × 10(-8) M for ruthenium anticancer drug 1, 7.0 × 10(-8) M for ruthenium anticancer drug 2, and 7.9× 10(-8) M for ruthenium anticancer drug 3, respectively. The relative restored fluorescence intensity was directly proportional to the concentration of ctDNA in the range of 1.0 × 10(-8) M ∼ 3.0 × 10(-7) M, with a correlation coefficient (R) of 0.9983 and a limit of detection of 1.1 × 10(-9) M. The relative standard deviation (RSD) for 1.5 × 10(-7) M ctDNA was 1.5% (n = 5). There was almost no interference to some common chemical compounds, nucleotides, amino acids, and proteins. The proposed method was applied to the determination of ctDNA in three synthetic samples with satisfactory results. The possible reaction mechanism of CdTe QDs fluorescence "OFF-ON" was further investigated. This simple and sensitive approach possessed some potential applications in the investigation of interaction between drug molecules and DNA

  11. Chemical hardness and density functional theory

    Indian Academy of Sciences (India)

    Keywords. Hardness; softness; hard & soft acids bases (HSAB); principle of maximum hardness (PMH) density functional theory (DFT). Abstract. The concept of chemical hardness is reviewed from a personal point of view. Author Affiliations. Ralph G Pearson1. Chemistry Department, University of California, Santa Barbara, ...

  12. Organometallic ruthenium complexes with thiosemicarbazone ligands: Synthesis, structure and cytotoxicity of [(η6-p-cymene)Ru(NS)Cl]+ (NS = 9-anthraldehyde thiosemicarbazones)

    OpenAIRE

    Beckford, Floyd A.; Leblanc, Gabriel; Thessing, Jeffrey; Shaloski, Michael; Frost, Brian J.; Li, Liya; Seeram, Navindra P.

    2009-01-01

    A series of half-sandwich arene-ruthenium complexes of the type [(η6-p-cymene) Ru(thiosemicarbazone)Cl]+ have been synthesized and their biological activity investigated. The first structurally characterized arene-ruthenium half-sandwich complex with a thiosemicarbazone ligand is reported.

  13. Synthesis and Catalytic Activity of Ruthenium-Indenylidene Complexes for Olefin Metathesis: Microscale Experiments for the Undergraduate Inorganic or Organometallic Laboratories

    Science.gov (United States)

    Pappenfus, Ted M.; Hermanson, David L.; Ekerholm, Daniel P.; Lilliquist, Stacie L.; Mekoli, Megan L.

    2007-01-01

    A series of experiments for undergraduate laboratory courses (e.g., inorganic, organometallic or advanced organic) have been developed. These experiments focus on understanding the design and catalytic activity of ruthenium-indenylidene complexes for olefin metathesis. Included in the experiments are the syntheses of two ruthenium-indenylidene…

  14. Where does the water go? A computational study on the reactivity of a ruthenium(V) oxo complex (bpc)(bpy)Ru(V)O.

    Science.gov (United States)

    Wang, Ying; Ahlquist, Mårten S G

    2014-06-21

    Two possible reactive sites (the oxo site and the Ru site) for water on a high-valent ruthenium(V) oxo complex were examined. Our results suggest that the reaction on the ruthenium (via a seven coordinate intermediate) has both a lower barrier and a product with a lower free energy than the product of addition at the oxo.

  15. Short hard palate in prenatal trisomy 21

    DEFF Research Database (Denmark)

    Lauridsen, H; Hansen, Birgit; Reintoft, I

    2005-01-01

    Structured Abstract Authors - Lauridsen H, Hansen BF, Reintoft I, Keeling JW, Skovgaard LT, Kjaer I Objective - The aim of the present study was for the first time to examine on postmortal material the total midpalatal length of the hard palate and the length of its two components (the maxillary...... and palatine parts) in trisomy 21 fetuses, and to compare the results to normal standards. Design - Material from 31 human fetuses with genetically verified trisomy 21 was studied. The fetuses were derived from legally induced or spontaneous abortions. Palates were, after sectioning, radiographed in lateral...... of the palatal components in trisomy 21 was compared to normal standards. Results - For CRL 150 mm and CRL 170 mm it appears that all three palatal lengths, total length, maxillary length, and palatinal length are significantly shorter in fetuses with trisomy 21. Conclusion - The main conclusion of our study...

  16. The synthesis and antiparasitic activity of aryl- and ferrocenyl-derived thiosemicarbazone ruthenium(II)-arene complexes.

    Science.gov (United States)

    Adams, Muneebah; Li, Yiqun; Khot, Heena; De Kock, Carmen; Smith, Peter J; Land, Kirkwood; Chibale, Kelly; Smith, Gregory S

    2013-04-07

    A series of aryl-functionalized and ferrocenyl monothiosemicarbazone compounds (L1-L4) were synthesized in moderate yields via a general Schiff-base condensation reaction. The thiosemicarbazone (TSC) ligands were reacted with the ruthenium dimer [Ru(Ar)(μ-Cl)Cl](2) (Ar = benzene; p-cymene) to yield a series of cationic mononuclear ruthenium(II)-arene thiosemicarbazone complexes of the general type [Ru(Cl)(TSC)(Ar)]Cl (1-8). The thiosemicarbazone ligands act as bidentate chelating ligands that coordinate to the ruthenium(ii) ion via the imine nitrogen and the thione sulfur atoms. The thiosemicarbazone ligands, as well as their metal complexes, were characterized by NMR, IR spectroscopy and ESI(+)-mass spectrometry. The molecular structure of the mononuclear ruthenium(II)-arene thiosemicarbazone complex (6) was determined by single-crystal X-ray diffraction analysis. The ruthenium(II)-arene thiosemicarbazone complexes were further evaluated for their in vitro antiparasitic activities against the Plasmodium falciparum chloroquine-sensitive (NF54) and chloroquine-resistant (Dd2) strains, as well as the G3 strain of Trichomonas vaginalis.

  17. Anti-inflammatory and Anti-nociceptive Activity of Ruthenium Complexes with Isonicotinic and Nicotinic Acids (Niacin) as Ligands.

    Science.gov (United States)

    Freitas, Cristina S; Roveda, Antonio C; Truzzi, Daniela R; Garcia, André C; Cunha, Thiago M; Cunha, Fernando Q; Franco, Douglas W

    2015-06-11

    This work evaluated the analgesic and anti-inflammatory activity of ruthenium(II) complexes trans-[Ru(NO(+))(NH3)4(L)](BF4)3 and [Ru(NH3)5(L)](BF4)3 containing the nonsteroidal anti-inflammatory drugs nicotinic acid (Hnic) and its isomer isonicotinic acid (ina) as ligands (L). The anti-nociceptive potential of these complexes and the free ligands (noncoordinated to ruthenium) was tested in different models with doses ranging from 1 to 100 μmol/kg. The ligands themselves were inactive; however, the ruthenium complexes containing Hnic and ina inhibited mechanical hyperalgesia induced by prostaglandin E2, carrageenan-induced hyperalgesia, and antigen-induced arthritis. Moreover, the ruthenium complexes inhibited overt nociception induced by formalin, acetic acid, capsaicin, and cinnamaldehyde. The mechanism involved in the anti-nociceptive effects of the ruthenium complexes suggested that ATP-sensitive K(+) channel pathways were not involved because glibenclamide did not affect their anti-nociceptive activities. However, the anti-nociceptive effect appears to be a consequence of the reduction in neutrophil migration and inhibition of the protein kinase C pathway.

  18. Charpy Impact Energy and Microindentation Hardness of 60-NITINOL

    Science.gov (United States)

    Stanford, Malcolm K.

    2012-01-01

    60-NITINOL (60 wt.% Ni 40 wt.% Ti) is being studied as a material for advanced aerospace components. The Charpy impact energy and microindentation hardness has been studied for this material, fabricated by vacuum induction skull melting (casting) and by hot isostatic pressing. Test specimens were prepared in various hardened and annealed heat treatment conditions. The average impact energy ranged from 0.33 to 0.49J for the hardened specimens while the annealed specimens had impact energies ranging from 0.89 to 1.18J. The average hardness values of the hardened specimens ranged from 590 to 676 HV while that of the annealed specimens ranged from 298 to 366 HV, suggesting an inverse relationship between impact energy and hardness. These results are expected to provide guidance in the selection of heat treatment processes for the design of mechanical components.

  19. Stress in hard metal films

    NARCIS (Netherlands)

    Janssen, G.C.A.M.; Kamminga, J.D.

    2004-01-01

    In the absence of thermal stress, tensile stress in hard metal films is caused by grain boundary shrinkage and compressive stress is caused by ion peening. It is shown that the two contributions are additive. Moreover tensile stress generated at the grain boundaries does not relax by ion

  20. Inclusive Hard Diffraction at HERA

    CERN Document Server

    Proskuryakov, Alexander

    2010-01-01

    Recent data from the H1 and ZEUS experiments on hard inclusive diffraction are discussed. Results of QCD analyses of the diffractive deep-inelastic scattering processes are reported. Predictions based on the extracted parton densities are compared to diffractive dijet measurements.

  1. Hard processes in hadronic interactions

    Energy Technology Data Exchange (ETDEWEB)

    Satz, H. [CERN, Geneva (Switzerland)]|[Universitat Bielefeld (Germany); Wang, X.N. [Lawrence Berkeley Lab., CA (United States)

    1995-07-01

    Quantum chromodynamics is today accepted as the fundamental theory of strong interactions, even though most hadronic collisions lead to final states for which quantitative QCD predictions are still lacking. It therefore seems worthwhile to take stock of where we stand today and to what extent the presently available data on hard processes in hadronic collisions can be accounted for in terms of QCD. This is one reason for this work. The second reason - and in fact its original trigger - is the search for the quark-gluon plasma in high energy nuclear collisions. The hard processes to be considered here are the production of prompt photons, Drell-Yan dileptons, open charm, quarkonium states, and hard jets. For each of these, we discuss the present theoretical understanding, compare the resulting predictions to available data, and then show what behaviour it leads to at RHIC and LHC energies. All of these processes have the structure mentioned above: they contain a hard partonic interaction, calculable perturbatively, but also the non-perturbative parton distribution within a hadron. These parton distributions, however, can be studied theoretically in terms of counting rule arguments, and they can be checked independently by measurements of the parton structure functions in deep inelastic lepton-hadron scattering. The present volume is the work of Hard Probe Collaboration, a group of theorists who are interested in the problem and were willing to dedicate a considerable amount of their time and work on it. The necessary preparation, planning and coordination of the project were carried out in two workshops of two weeks` duration each, in February 1994 at CERn in Geneva andin July 1994 at LBL in Berkeley.

  2. Neoplasms of the hard palate.

    Science.gov (United States)

    Aydil, Utku; Kızıl, Yusuf; Bakkal, Faruk Kadri; Köybaşıoğlu, Ahmet; Uslu, Sabri

    2014-03-01

    Although the most common neoplastic lesion of the oral cavity is squamous cell carcinoma (SCC), primary neoplastic lesions of the hard palate have not been systematically reviewed to date. The aim of this study was to determine the histopathologic composition and characteristics of neoplasms of the hard palate. A retrospective analysis of 66 patients with a primary neoplasm of the hard palate managed at the authors' institution from 1985 through 2012 was performed. Demographic features, malignancy rate, histopathologic characteristics and distribution, TNM staging results, metastasis patterns, and management strategies were investigated. The sample was composed of 66 patients (mean age, 45.0 yr; 57.6% men). Neoplasms were benign in 57.6% of cases and malignant in 42.4%. Epithelial neoplasms and mesenchymal neoplasms were encountered in 52 patients (78.8%) and 14 patients (21.2%), respectively. Minor salivary gland tumors (MSGTs) were the most common histopathologic group (60.6%), followed by benign mesenchymal tumors (15.2%), SCCs (12.1%), malignant melanomas (6.1%), lymphomas (3.0%), and sarcomas (3.0%). Although 75.0% of malignant epithelial neoplasms were at an advanced stage, there were no pN+ SCC or malignant MSGT cases at presentation. The most common neoplasms of the hard palate were MSGTs. SCCs were relatively rare in this series. Although three-fourths of neoplasms were at an advanced stage, neck metastasis was not a characteristic of malignant epithelial neoplasms located in the hard palate. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  3. Optimization of surface integrity in dry hard turning using RSM

    Indian Academy of Sciences (India)

    This paper investigates the effect of different cutting parameters (cutting speed, feed rate, and depth of cut) on surface integrity defined in terms of surface roughness and microhardness in dry hard turning process. The workpiece material used was hardened alloy steel AISI 52100 and it was machined on a CNC lathe with ...

  4. Improving Nano-Hardness of Stainless Steel Cr18Ni10Ti Through Electrochemical Machining

    OpenAIRE

    Van, Nguyen Thi Hong

    2016-01-01

    One of the major mechanical and physical parameters for surface quality is hardness. In this paper was studied the electrochemical machining (ECM) to improve the surface micro-hardness and nano-hardness of stainless steel samples. The materials studied are used as samples of stainless steel Cr18Ni10Ti after electrochemical machining under different current density in a water solution of NaCl with various concentrations. The results showed that with increasing the current density from 0 to 28....

  5. Physicochemical properties and creep strength of a single crystal of nickel-base superalloy containing rhenium and ruthenium

    Energy Technology Data Exchange (ETDEWEB)

    Petrushin, Nikolay V.; Svetlow, Igor L.; Samoylov, Andrey I.; Morozova, Galina I. [All-Russia Institute of Aviation Materials, Moscow (Russian Federation)

    2010-05-15

    The influence of alloying elements, including rhenium and ruthenium, on the physicochemical and structural parameters of single crystal nickel-base superalloys has been analyzed. The results were used in computer designing of a single crystal nickel-base superalloy containing rhenium and ruthenium. The optimized alloy composition, providing the best physicochemical properties and longest creep lifetime, contains 6 wt.% rhenium and 4 wt.% ruthenium. <001> single crystals of the designed superalloy were directionally solidified and investigated in as-cast, heat treated and creep deformed conditions. The investigations included: characterization of the superalloy microstructure, dendritic segregation of alloying elements, their partition between the {gamma}- and {gamma}'-phases etc. Creep rupture tests were performed in the temperature interval of 900-1100 C and included tests longer 1000 h. (orig.)

  6. Speciation of ruthenium in organic TBP/TPH organic phases: a study about acidity of nitric solutions

    Energy Technology Data Exchange (ETDEWEB)

    Lefebvre, C.; Dumas, T.; Charbonnel, M.C. [CEA, Centre de Marcoule, DEN/DRCP/SMCS/LILA, Bat. 181, BP 17171, 30207 Bagnols-sur-Ceze (France); Solari, P.L. [Synchrotron SOLEIL, L' Orme des Merisiers, BP 48, St Aubin, 91192 Gif-sur-Yvette (France)

    2016-07-01

    Ruthenium extraction with uranium and plutonium during the reprocessing of nuclear used fuel is an important element to follow because its presence leads to a decrease of the decontamination factors and causes enhanced radiolysis of the solvent. A study was carried out on the speciation of ruthenium in both aqueous and organic phases by complementary spectroscopic techniques such as Fourier Transform Infrared spectroscopy (FTIR) and X-ray absorption spectroscopy. The results show a different Ru extraction behavior depending on the initial HNO{sub 3} conditions (1 M - 4 M). It also provides evidence of a second shell TBP-Ru complexation. By providing a better understanding of the ruthenium extraction mechanism, this study will help to support the modeling of related processes.

  7. Ruthenium-cobalt nanoalloys encapsulated in nitrogen-doped graphene as active electrocatalysts for producing hydrogen in alkaline media

    Science.gov (United States)

    Su, Jianwei; Yang, Yang; Xia, Guoliang; Chen, Jitang; Jiang, Peng; Chen, Qianwang

    2017-04-01

    The scalable production of hydrogen could conveniently be realized by alkaline water electrolysis. Currently, the major challenge confronting hydrogen evolution reaction (HER) is lacking inexpensive alternatives to platinum-based electrocatalysts. Here we report a high-efficient and stable electrocatalyst composed of ruthenium and cobalt bimetallic nanoalloy encapsulated in nitrogen-doped graphene layers. The catalysts display remarkable performance with low overpotentials of only 28 and 218 mV at 10 and 100 mA cm-2, respectively, and excellent stability of 10,000 cycles. Ruthenium is the cheapest platinum-group metal and its amount in the catalyst is only 3.58 wt.%, showing the catalyst high activity at a very competitive price. Density functional theory calculations reveal that the introduction of ruthenium atoms into cobalt core can improve the efficiency of electron transfer from alloy core to graphene shell, beneficial for enhancing carbon-hydrogen bond, thereby lowing ΔGH* of HER.

  8. Proceedings of the Tungsten Workshop for Hard Target Weapons Program

    Energy Technology Data Exchange (ETDEWEB)

    Mackiewicz-Ludtka, G.; Hayden, H.W.; Davis, R.M.

    1995-06-01

    The purpose of this meeting was to review and exchange information and provide technical input for improving technologies relevant to the Hard Target Weapons Program. This workshop was attended by representatives from 17 organizations, including 4 Department of Defense (DoD) agencies, 8 industrial companies, and 5 laboratories within DOE. Hard targets are defined as reinforced underground structures that house enemy forces, weapon systems, and support equipment. DOE-ORO and Martin Marietta Energy Systems, Inc. (Energy Systems) have been involved in advanced materials research and development (R&D) for several DOE and DoD programs. These programs are conducted in close collaboration with Eglin AFB, Department of the Army`s Picatinny Arsenal, and other DoD agencies. As part of this ongoing collaboration, Eglin AFB and Oak Ridge National Laboratory planned and conducted this workshop to support the Hard Target Weapons Program. The objectives of this workshop were to (1) review and identify the technology base that exists (primarily due to anti-armor applications) and assess the applicability of this technology to the Hard Target Weapons Program requirements; (2) determine future directions to establish the W materials, processing, and manufacturing technologies suitable for use in fixed, hard target penetrators; and (3) identify and prioritize the potential areas for technical collaboration among the participants.

  9. Porous Biodegradable Metals for Hard Tissue Scaffolds: A Review

    Directory of Open Access Journals (Sweden)

    A. H. Yusop

    2012-01-01

    Full Text Available Scaffolds have been utilized in tissue regeneration to facilitate the formation and maturation of new tissues or organs where a balance between temporary mechanical support and mass transport (degradation and cell growth is ideally achieved. Polymers have been widely chosen as tissue scaffolding material having a good combination of biodegradability, biocompatibility, and porous structure. Metals that can degrade in physiological environment, namely, biodegradable metals, are proposed as potential materials for hard tissue scaffolding where biodegradable polymers are often considered as having poor mechanical properties. Biodegradable metal scaffolds have showed interesting mechanical property that was close to that of human bone with tailored degradation behaviour. The current promising fabrication technique for making scaffolds, such as computation-aided solid free-form method, can be easily applied to metals. With further optimization in topologically ordered porosity design exploiting material property and fabrication technique, porous biodegradable metals could be the potential materials for making hard tissue scaffolds.

  10. In-situ XPS analysis of oxidized and reduced plasma deposited ruthenium-based thin catalytic films

    Science.gov (United States)

    Balcerzak, Jacek; Redzynia, Wiktor; Tyczkowski, Jacek

    2017-12-01

    A novel in-situ study of the surface molecular structure of catalytically active ruthenium-based films subjected to the oxidation (in oxygen) and reduction (in hydrogen) was performed in a Cat-Cell reactor combined with a XPS spectrometer. The films were produced by the plasma deposition method (PEMOCVD). It was found that the films contained ruthenium at different oxidation states: metallic (Ru0), RuO2 (Ru+4), and other RuOx (Ru+x), of which content could be changed by the oxidation or reduction, depending on the process temperature. These results allow to predict the behavior of the Ru-based catalysts in different redox environments.

  11. High hardness in the biocompatible intermetallic compound β-Ti3Au.

    Science.gov (United States)

    Svanidze, Eteri; Besara, Tiglet; Ozaydin, M Fevsi; Tiwary, Chandra Sekhar; Wang, Jiakui K; Radhakrishnan, Sruthi; Mani, Sendurai; Xin, Yan; Han, Ke; Liang, Hong; Siegrist, Theo; Ajayan, Pulickel M; Morosan, E

    2016-07-01

    The search for new hard materials is often challenging, but strongly motivated by the vast application potential such materials hold. Ti3Au exhibits high hardness values (about four times those of pure Ti and most steel alloys), reduced coefficient of friction and wear rates, and biocompatibility, all of which are optimal traits for orthopedic, dental, and prosthetic applications. In addition, the ability of this compound to adhere to ceramic parts can reduce both the weight and the cost of medical components. The fourfold increase in the hardness of Ti3Au compared to other Ti-Au alloys and compounds can be attributed to the elevated valence electron density, the reduced bond length, and the pseudogap formation. Understanding the origin of hardness in this intermetallic compound provides an avenue toward designing superior biocompatible, hard materials.

  12. Strength of the rare-earth-transition-metal exchange coupling in hard magnetic materials, an experimental approach based on high-field magnetisation measurements: Application to Er sub 2 Fe sub 14 B

    Energy Technology Data Exchange (ETDEWEB)

    Verhoef, R.; Radwanski, R.J.; Franse, J.J.M. (Natuurkundig Lab., Univ. van Amsterdam (Netherlands))

    1990-09-01

    A new experimental technique is presented to determine the intersublattice molecular-field coefficient, n{sub RT}, in heavy rare-earth-transition-metal intermetallic compounds. The technique is based on high-field magnetisation measurements on finely powdered polycrystalline material that is free to rotate in the sampleholder. Experimental results are reported for a number of Er{sub 2}Fe{sub 14-x}Mn{sub x}B compounds. The strength of the R-T exchange coupling is not affected by the Mn substitution, and a value of 0.445 Tkg/Am{sup 2} has been deduced for the coefficient n{sub RT}. (orig.).

  13. Loss and Reformation of Ruthenium Alkylidene: Connecting Olefin Metathesis, Catalyst Deactivation, Regeneration, and Isomerization.

    Science.gov (United States)

    Engel, Julien; Smit, Wietse; Foscato, Marco; Occhipinti, Giovanni; Törnroos, Karl W; Jensen, Vidar R

    2017-11-08

    Ruthenium-based olefin metathesis catalysts are used in laboratory-scale organic synthesis across chemistry, largely thanks to their ease of handling and functional group tolerance. In spite of this robustness, these catalysts readily decompose, via little-understood pathways, to species that promote double-bond migration (isomerization) in both the 1-alkene reagents and the internal-alkene products. We have studied, using density functional theory (DFT), the reactivity of the Hoveyda-Grubbs second-generation catalyst 2 with allylbenzene, and discovered a facile new decomposition pathway. In this pathway, the alkylidene ligand is lost, via ring expansion of the metallacyclobutane intermediate, leading to the spin-triplet 12-electron complex (SIMes)RuCl2 ((3)R21, SIMes = 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene). DFT calculations predict (3)R21 to be a very active alkene isomerization initiator, either operating as a catalyst itself, via a η(3)-allyl mechanism, or, after spin inversion to give R21 and formation of a cyclometalated Ru-hydride complex, via a hydride mechanism. The calculations also suggest that the alkylidene-free ruthenium complexes may regenerate alkylidene via dinuclear ruthenium activation of alkene. The predicted capacity to initiate isomerization is confirmed in catalytic tests using p-cymene-stabilized R21 (5), which promotes isomerization in particular under conditions favoring dissociation of p-cymene and disfavoring formation of aggregates of 5. The same qualitative trends in the relative metathesis and isomerization selectivities are observed in identical tests of 2, indicating that 5 and 2 share the same catalytic cycles for both metathesis and isomerization, consistent with the calculated reaction network covering metathesis, alkylidene loss, isomerization, and alkylidene regeneration.

  14. The effect of annealing temperature on the optical properties of a ruthenium complex thin film

    Energy Technology Data Exchange (ETDEWEB)

    Ocakoglu, Kasim, E-mail: kasim.ocakoglu@mersin.edu.tr [Advanced Technology Research & Application Center, Mersin University, TR-33343, Yenisehir, Mersin (Turkey); Department of Energy Systems Engineering, Faculty of Technology, Mersin University, TR-33480 Mersin (Turkey); Okur, Salih, E-mail: salih.okur@ikc.edu.tr [Department of Materials Science and Engineering, Faculty of Engineering and Architecture, Izmir Katip Celebi University, Izmir (Turkey); Aydin, Hasan [Izmir Institute of Technology, Department of Material Science and Engineering, Gulbahce Campus, 35430, Urla, Izmir (Turkey); Emen, Fatih Mehmet [Faculty of Arts and Sciences, Department of Chemistry, Mehmet Akif Ersoy University, TR-15030 Burdur (Turkey)

    2016-08-01

    The stability of the optical parameters of a ruthenium polypyridyl complex (Ru-PC K314) film under varying annealing temperatures between 278 K and 673 K was investigated. The ruthenium polypyridyl complex thin film was prepared on a quartz substrate by drop casting technique. The transmission of the film was recorded by using Ultraviolet/Visible/Near Infrared spectrophotometer and the optical band gap energy of the as-deposited film was determined around 2.20 eV. The optical parameters such as refractive index, extinction coefficient, and dielectric constant of the film were determined and the annealing effect on these parameters was investigated. The results show that Ru PC K314 film is quite stable up to 595 K, and the rate of the optical band gap energy change was found to be 5.23 × 10{sup −5} eV/K. Furthermore, the thermal analysis studies were carried out in the range 298–673 K. The Differential Thermal Analysis/Thermal Gravimmetry/Differantial Thermal Gravimmetry curves show that the decomposition is incomplete in the temperature range 298–673 K. Ru-PC K314 is thermally stable up to 387 K. The decomposition starts at 387 K with elimination of functional groups such as CO{sub 2}, CO molecules and SO{sub 3}H group was eliminated between 614 K and 666 K. - Highlights: • Optical parameters of a ruthenium polypyridyl complex film under varying annealing temperatures • The film is quite stable up to 573 K. • The rate of change of optical energy gap was obtained as 5.23 × 10{sup −5} eV/K.

  15. Hardness and thermal stability of cubic silicon nitride

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Kragh, Flemming; Frost, D. J.

    2001-01-01

    The hardness and thermal stability of cubic spinel silicon nitride (c-Si3N4), synthesized under high-pressure and high-temperature conditions, have been studied by microindentation measurements, and x-ray powder diffraction and scanning electron microscopy, respectively The phase at ambient...... temperature has an average hardness of 35.31 GPa, slightly larger than SiO2 stishovite, which is often referred to as the third hardest material after diamond and cubic boron nitride. The cubic phase is stable up to 1673 K in air. At 1873 K, alpha -and beta -Si3N4 phases are observed, indicating a phase...

  16. Hard gap in epitaxial semiconductor-superconductor nanowires

    DEFF Research Database (Denmark)

    Chang, W.; Albrecht, S. M.; Jespersen, T. S.

    2015-01-01

    information processing. Proposals in this direction based on proximity effect in semiconductor nanowires are appealing because the key ingredients are currently in hand. However, previous instances of proximitized semiconductors show significant tunneling conductance below the superconducting gap, suggesting...... a continuum of subgap states---a situation that nullifies topological protection. Here, we report a hard superconducting gap induced by proximity effect in a semiconductor, using epitaxial Al-InAs superconductor-semiconductor nanowires. The hard gap, along with favorable material properties and gate...

  17. CMS results on hard diffraction

    CERN Document Server

    INSPIRE-00107098

    2013-01-01

    In these proceedings we present CMS results on hard diffraction. Diffractive dijet production in pp collisions at $\\sqrt{s}$=7 TeV is discussed. The cross section for dijet production is presented as a function of $\\tilde{\\xi}$, representing the fractional momentum loss of the scattered proton in single-diffractive events. The observation of W and Z boson production in events with a large pseudo-rapidity gap is also presented.

  18. MANAGEMENT AND TREATMENT OF WATER FROM HARD-ROCK MINES {ENGINEERING ISSUE}

    Science.gov (United States)

    This Engineering Issue document on treatment of mining waters is a practical guide to understanding and selecting technologies for the environmental management of waste materials and effluents at hard-rock mines. For the purposes of this discussion, hard-rock mining primarily ref...

  19. Parameters optimization, microstructure and micro-hardness of silicon carbide laser deposited on titanium alloy

    CSIR Research Space (South Africa)

    Adebiyia, DI

    2016-06-01

    Full Text Available Silicon carbide (SiC), has excellent mechanical properties such as high hardness and good wear resistance, and would have been a suitable laser-coating material for titanium alloy to enhance the poor surface hardness of the alloy. However, SiC has...

  20. Comparison of Different Bleaching Treatments Effect on Micro Hardness of Four Different Aged Composites

    OpenAIRE

    Danesh Kazemi; Johar

    2016-01-01

    Background In this study, four different types of composite samples were aged then exposed to 16% carbamide peroxide and 40% hydrogen peroxide, and the results were compared to a control group. Objectives The aim of this study was to investigate variations of micro hardness in types of composite materials after bleaching treatments and comparison of hardness in types of composites. Methods ...

  1. Synthetic routes to ruthenium (ii) species containing carboxylate-functionalized 2,2`-bipyridine ligands

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, T.; Patterson, A.; Keene, F.R. [James Cook University, Townsville, QLD (Australia). School of Biomedical and Molecular Sciences

    1998-12-31

    Two methods are reported for the incorporation of carboxylate substituents on polypyridyl ligands coordinated to ruthenium(ll) centres. In the first, a precursor complex is synthesized with ethoxycarbonyl groups which are subsequently base-hydrolysed to produce the carboxylate in high yield (-CO{sub 2}Et{yields} -CO{sub 2}H). In the second method, ruthenyl species were used to chemically catalyse the electochemical oxidation of methyl substituents on the ligands of a precursor complex to produce the target carboxylate species (-CH{sub 3} {yields} -CO{sub 2}H). Copyright (1998) CSIRO Australia 21 refs., 1 tab., 1 fig.

  2. Formation and microscopical application of a fluorescent 1,10-phenanthroline derivative of ruthenium red.

    Science.gov (United States)

    Bertolesi, G E; de Cidre, L L; Stockert, J C

    1995-10-01

    In this work we describe the formation and microscopical application of a fluorescent derivative of Ruthenium Red (RR) obtained by heating the dye in the presence of 1,10-phenanthroline (OP). The RR-OP reaction product showed absorption maxima at 416 and 444 nm and intense fluorescence emission at 578 nm under 440 nm exciting light. Neither RR nor OP solutions alone were fluorescent when excited at 440 nm. Using fluorescence microscopy, chicken blood cell smears stained 5 min with the RR-OP derivative showed the chromatin of erythrocyte nuclei with a bright orange fluorescence under violet-blue (436 nm) exciting light.

  3. (106)Ruthenium brachytherapy for ciliary recurrence with supraciliary effusion in retinoblastoma.

    Science.gov (United States)

    Chhablani, Jay; Romanzo, Antonio; Balmer, Aubin; Pica, Alessia; Gaillard, Marie-Claire; Cozza, Raffaele; Moeckli, Raphaël; Munier, Francis L

    2010-12-01

    A 2-year-old boy with syndromic bilateral retinoblastoma resulting from a (del(13)(q12.3q14.3)) developed a recurrent tumor measuring 2.3 X 2.3 mm at the ora serrata 15 months following last treatment. Ultrasound biomicroscopy (UBM) revealed a mass invading the ciliary body 6.6 mm in diameter associated with a localized supraciliary effusion. Complete tumor regression was achieved 1 month after brachytherapy with a (106)Ruthenium plaque. There was no recurrence at 16 months. This is the first clinical demonstration of supraciliary effusion in recurrent retinoblastoma. Brachytherapy appears to be effective in the treatment of this type of recurrence.

  4. A Ruthenium Catalyst for Olefin Metathesis Featuring an Anti-Bredt N-Heterocyclic Carbene Ligand.

    Science.gov (United States)

    Martin, David; Marx, Vanessa M; Grubbs, Robert H; Bertrand, Guy

    2016-03-17

    A ruthenium complex bearing an "anti-Bredt" N-heterocyclic carbene was synthesized, characterized and evaluated as a catalyst for olefin metathesis. Good conversions were observed at room temperature for the formation of di- and tri-substituted olefins by ring-closing metathesis. It also allowed for the ring-opening metathesis polymerization of cyclooctadiene, as well as for the cross-metathesis of cis-1,4-diacetoxy-2-butene with allyl-benzene, with enhanced Z/E kinetic selectivity over classical NHC-based catalysts.

  5. Olefin Metathesis With Ruthenium-Arene Catalysts Bearing N-Heterocyclic Carbene Ligands

    Science.gov (United States)

    Delaude, Lionel; Demonceau, Albert

    In this chapter, we summarize the main results of our investigations on the ring-opening metathesis polymerization (ROMP) of cyclooctene catalyzed by various ruthenium (Ru)-arene complexes bearing imidazolin-2-ylidene, imidazolidin- 2-ylidene, or triazolin-5-ylidene ligands. Three major findings emerged from this study. First, we underscored the intervention of a photochemical activation step due to visible light illumination. Second, we established that the presence of an endocyclic double bond in the carbene ligand central heterocycle was not crucial to achieve high catalytic efficiencies. Third, we demonstrated that ortho-metallation of the N-heterocyclic carbene (NHC) ligand by the Ru center led to inactive catalysts.

  6. Evaluation of Ruthenium Capture Methods for Tritium Pretreatment Off-Gas Streams

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Barry B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Strachan, Denis M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-07-01

    In the reprocessing of used nuclear fuel, radioactive elements are released into various plant off-gas streams. While much research and development has focused on the abatement of the volatile nuclides 3H, 14C, 85Kr, and 129I, the potential release of semivolatile isotopes that could also report to the off-gas streams in a reprocessing facility has been examined. Ruthenium (as 106Ru) has been identified as one of the semivolatile nuclides requiring the greatest degree of abatement prior to discharging the plant off-gas to the environment.

  7. Dynamic modeling of the cesium, strontium, and ruthenium transfer to grass and vegetables

    Energy Technology Data Exchange (ETDEWEB)

    Renaud, P.; Real, J.; Maubert, H.; Roussel-Debet, S. (CE de Cadarache, Saint-Paul lez Durance (France). Inst. de Protection et de Surete Nucleaire)

    1999-05-01

    From 1988 to 1993, the Nuclear Safety and Protection Institute (Institut de Protection et de Surete Nucleaire -- IPSN) conducted experimental programs focused on transfers to vegetation following accidental localized deposits of radioactive aerosols. In relation to vegetable crops (fruit, leaves, and root vegetables) and meadow grass these experiments have enabled a determination of the factors involved in the transfer of cesium, strontium, and ruthenium at successive harvests, or cuttings, in respect of various time lags after contamination. The dynamic modeling given by these results allows an evaluation of changes in the mass activity of vegetables and grass during the months following deposit. It constitutes part of the ASTRAL post-accident radioecology model.

  8. Ruthenium-Catalyzed Methylation of Amines with Paraformaldehyde in Water under Mild Conditions.

    Science.gov (United States)

    van der Waals, Dominic; Heim, Leo E; Gedig, Christian; Herbrik, Fabian; Vallazza, Simona; Prechtl, Martin H G

    2016-09-08

    Methylated amines are highly important for a variety of pharmaceutical and agrochemical applications. Existing routes for their formation result in the production of large amounts of waste or require high reaction temperatures, both of which impact the ecological and economical footprint of the methodologies. Herein, we report the ruthenium-catalyzed reductive methylation of a range of aliphatic amines, using paraformaldehyde as both substrate and hydrogen source, in combination with water. This reaction proceeds under mild aqueous reaction conditions. Additionally the use of a secondary phase for catalyst retention and recycling has been investigated with promising results. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. New aryloxybenzylidene ruthenium chelates – synthesis, reactivity and catalytic performance in ROMP

    Directory of Open Access Journals (Sweden)

    Patrycja Żak

    2015-10-01

    Full Text Available New phenoxybenzylidene ruthenium chelates were synthesised from the second generation Grubbs catalysts bearing a triphenylphosphine ligand (or its para-substituted analogues by metathesis exchange with substituted 2-vinylphenols. The complexes behave like a latent catalyst and are characterized by an improved catalytic behaviour as compared to that of the known analogues, i.e., they exhibit high catalytic inactivity in their dormant forms and a profound increase in activity after activation with HCl. The strong electronic influence of substituents in the chelating ligand on the catalytic activity was demonstrated. The catalytic properties were tested in ROMP of cyclooctadien (COD and a single selected norbornene derivative.

  10. Upconverting nanovesicles for the activation of ruthenium anti-cancer prodrugs with red light

    OpenAIRE

    Askes, S. H. C.

    2016-01-01

    Ruthenium complexes are promising prodrugs in photoactivated chemotherapy (PACT): to prevent systemic therapeutic side-effects, a non-toxic version of the drug is introduced in the body and is only activated at the place of the tumor by means of visible light irradiation. However, most of these PACT compounds are only sensitive for UV or blue light, while this light does not permeate the body very well, in contrast to red or near-infrared light. To circumvent this problem, the principle of li...

  11. Playing Moderately Hard to Get

    Directory of Open Access Journals (Sweden)

    Stephen Reysen

    2013-12-01

    Full Text Available In two studies, we examined the effect of different degrees of attraction reciprocation on ratings of attraction toward a potential romantic partner. Undergraduate college student participants imagined a potential romantic partner who reciprocated a low (reciprocating attraction one day a week, moderate (reciprocating attraction three days a week, high (reciprocating attraction five days a week, or unspecified degree of attraction (no mention of reciprocation. Participants then rated their degree of attraction toward the potential partner. The results of Study 1 provided only partial support for Brehm’s emotion intensity theory. However, after revising the high reciprocation condition vignette in Study 2, supporting Brehm’s emotion intensity theory, results show that a potential partners’ display of reciprocation of attraction acted as a deterrent to participants’ intensity of experienced attraction to the potential partner. The results support the notion that playing moderately hard to get elicits more intense feelings of attraction from potential suitors than playing too easy or too hard to get. Discussion of previous research examining playing hard to get is also re-examined through an emotion intensity theory theoretical lens.

  12. Magnetism Materials and Applications

    CERN Document Server

    Trémolet de Lacheisserie, Étienne; Schlenker, Michel

    2005-01-01

    This book treats permanent magnet (hard) materials, magnetically soft materials for low-frequency applications and for high-frequency electronics, magnetostrictive materials, superconductors, magnetic-thin films and multilayers, and ferrofluids. Chapters are dedicated to magnetic recording, the role of magnetism in magnetic resonance imaging (MRI), and instrumentation for magnetic measurements.   

  13. The ruthenium isotopic composition of the oceanic mantle

    Science.gov (United States)

    Bermingham, K. R.; Walker, R. J.

    2017-09-01

    The approximately chondritic relative, and comparatively high absolute mantle abundances of the highly siderophile elements (HSE), suggest that their concentrations in the bulk silicate Earth were primarily established during a final ∼0.5 to 1% of ;late accretion; to the mantle, following the cessation of core segregation. Consequently, the isotopic composition of the HSE Ru in the mantle reflects an amalgamation of the isotopic compositions of late accretionary contributions to the silicate portion of the Earth. Among cosmochemical materials, Ru is characterized by considerable mass-independent isotopic variability, making it a powerful genetic tracer of Earth's late accretionary building blocks. To define the Ru isotopic composition of the oceanic mantle, the largest portion of the accessible mantle, we report Ru isotopic data for materials from one Archean and seven Phanerozoic oceanic mantle domains. A sample from a continental lithospheric mantle domain is also examined. All samples have identical Ru isotopic compositions, within analytical uncertainties, indicating that Ru isotopes are well mixed in the oceanic mantle, defining a μ100Ru value of 1.2 ± 7.2 (2SD). The only known meteorites with the same Ru isotopic composition are enstatite chondrites and, when corrected for the effects of cosmic ray exposure, members of the Main Group and sLL subgroup of the IAB iron meteorite complex which have a collective CRE corrected μ100Ru value of 0.9 ± 3.0. This suggests that materials from the region(s) of the solar nebula sampled by these meteorites likely contributed the dominant portion of late accreted materials to Earth's mantle.

  14. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... Quitting drugs is hard because addiction is a brain disease. Your brain is like a control tower that sends out ... and choices. Addiction changes the signals in your brain and makes it hard to feel OK without ...

  15. Hardness of Potable Water in Southwestern Skane

    OpenAIRE

    Kos, Z.

    1982-01-01

    This paper is concerned with water hardness in the municipal water supply systems. After a general overview of the health aspects of water hardness, this issue is discussed in the specific context of Southwestern Skane, Sweden.

  16. Germanium content in Polish hard coals

    Directory of Open Access Journals (Sweden)

    Makowska Dorota

    2016-01-01

    Full Text Available Due to the policy of the European Union, it is necessary to search for new sources of scarce raw materials. One of these materials is germanium, listed as a critical element. This semi-metal is widely used in the electronics industry, for example in the production of semiconductors, fibre optics and solar cells. Coal and fly ash from its combustion and gasification for a long time have been considered as a potential source of many critical elements, particularly germanium. The paper presents the results of germanium content determination in the Polish hard coal. 23 coal samples of various coal ranks were analysed. The samples were collected from 15 mines of the Upper Silesian Coal Basin and from one mine of the Lublin Coal Basin. The determination of germanium content was performed with the use of Atomic Absorption Spectrometry with Electrothermal Atomization (GFAAS. The investigation showed that germanium content in the analysed samples was at least twice lower than the average content of this element in the hard coals analysed so far and was in the range of 0.08 ÷ 1.28 mg/kg. Moreover, the content of Ge in the ashes from the studied coals does not exceed 15 mg/kg, which is lower than the average value of Ge content in the coal ashes. The highest content of this element characterizes coals of the Lublin Coal Basin and young coals type 31 from the Vistula region. The results indicate a low utility of the analysed coal ashes as a source of the recovery of germanium. On the basis of the analyses, the lack of the relationship between the content of the element and the ash content in the tested coals was noted. For coals of the Upper Silesian Coal Basin, the relationship between the content of germanium in the ashes and the depth of the seam was observed.

  17. 7 CFR 201.30 - Hard seed.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seed. 201.30 Section 201.30 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard seed. The label shall show the percentage of hard seed, if...

  18. 7 CFR 201.21 - Hard seed.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seed. 201.21 Section 201.21 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21 Hard seed. The label shall show the percentage of hard seed...

  19. Systematic hardness measurements on single crystals and ...

    Indian Academy of Sciences (India)

    Vickers and knoop hardness measurements were carried out on CsBr and CsI single crystals. Polycrystalline blanks of CsCl, CsBr and CsI were prepared by melting and characterized by X-ray diffraction. Vickers hardness measurements were carried out on these blanks. The hardness values were correlated with the lattice ...

  20. 7 CFR 201.57 - Hard seeds.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seeds. 201.57 Section 201.57 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at...

  1. Systematic hardness studies on lithium niobate crystals

    Indian Academy of Sciences (India)

    Unknown

    1975) made Knoop hardness ... mentioned that Knoop and Vickers hardness values generally agree to within 5% (Mott 1956). Brown et al ... In the present communication, we report a detailed study of the load-dependence of hardness on two ...

  2. The impact of Metal-Ligand Cooperation in Hydrogenation of Carbon Dioxide Catalyzed by Ruthenium PNP Pincer

    NARCIS (Netherlands)

    Filonenko, G.A.; Conley, M.P.; Copéret, C.; Lutz, M.|info:eu-repo/dai/nl/304828971; Hensen, E.J.M.; Pidko, E.A.

    2013-01-01

    The metal–ligand cooperative activation of CO2 with pyridine-based ruthenium PNP pincer catalysts leads to pronounced inhibition of the activity in the catalytic CO2 hydrogenation to formic acid. The addition of water restores catalytic performance by activating alternative reaction pathways and

  3. Dehydrogenative Synthesis of Imines from Alcohols and Amines Catalyzed by a Ruthenium N-Heterocyclic Carbene Complex

    DEFF Research Database (Denmark)

    Maggi, Agnese; Madsen, Robert

    2012-01-01

    A new method for the direct synthesis of imines from alcohols and amines is described where hydrogen gas is liberated. The reaction is catalyzed by the ruthenium N-heterocyclic carbene complex [RuCl2(IiPr)(p-cymene)] in the presence of the ligand DABCO and molecular sieves. The imination can...

  4. Effect of Support in Heterogeneous Ruthenium Catalysts Used for the Selective Aerobic Oxidation of HMF in Water

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Riisager, Anders

    2011-01-01

    Heterogeneous ruthenium-based catalysts were applied in the selective, aerobic oxidation of 5-hydroxymethylfurfural, a versatile biomass-derived chemical, to form 2,5-furandicarboxylic acid. The oxidation reactions were performed in water with dioxygen as the oxidant at different pressures without...

  5. New carboxy-functionalized terpyridines as precursors for zwitterionic ruthenium complexes for polymer-based solar cells

    DEFF Research Database (Denmark)

    Duprez, V.; Krebs, Frederik C

    2006-01-01

    New carboxy-terpyridines selectively functionalized at the 4-, 4'- and 4"-positions were prepared in a three-step procedure with good yields using, the Krohnke reaction followed by saponification. Their complexation with ruthenium led to symmetric and unsymmetric terpyridinyl zwitterionic complexes...

  6. A quantitative electron tomography study of ruthenium particles on the interior and exterior surfaces of carbon nanotubes

    NARCIS (Netherlands)

    Friedrich, H.|info:eu-repo/dai/nl/304837350; Guo, S.; de Jongh, P.E.|info:eu-repo/dai/nl/186125372; Pan, X.; Bao, X.|info:eu-repo/dai/nl/371576679; de Jong, K.P.|info:eu-repo/dai/nl/06885580X

    2011-01-01

    The efficiency of filling carbon nanotubes (CNTs) by ultrasound-assisted wet impregnation is quantified by electron tomography (ET). For image analysis, a method that combines edge detection with single-value thresholding is proposed and validated. A high proportion (80 wt %) of the ruthenium was

  7. Characterisation and application of new carboxylic acid-functionalised ruthenium complexes as dye-sensitisers for solar cells

    DEFF Research Database (Denmark)

    Duprez, Virginie; Biancardo, Matteo; Krebs, Frederik C

    2007-01-01

    A series of ruthenium complexes with and without TiO2, anchoring carboxylic acid groups have been synthesised and characterised using nuclear magnetic resonance (NMR), UV-vis and luminescence. These complexes were adsorbed on thin films of the wide band-gap semiconductor anatase and were tested...

  8. Ruthenium Olefin Metathesis Catalysts Bearing an N-Fluorophenyl-N-Mesityl-Substituted Unsymmetrical N-Heterocyclic Carbene

    OpenAIRE

    Vougioukalakis, Georgios C.; Grubbs, Robert H

    2007-01-01

    Two new ruthenium-based olefin metathesis catalysts, each bearing an unsymmetrical N-heterocyclic carbene ligand, have been synthesized and fully characterized. Their catalytic performance has been evaluated in ring-closing metathesis, cross metathesis, and ring-opening metathesis polymerization reactions.

  9. Synthesis and structures of ruthenium di- and tricarbonyl complexes derived from 4,5-diazafluoren-9-one.

    Science.gov (United States)

    Jimenez, Jorge; Chakraborty, Indranil; Mascharak, Pradip

    2015-11-01

    Carbon monoxide (CO) has recently been shown to impart beneficial effects in mammalian physiology and considerable research attention is now being directed toward metal-carbonyl complexes as a means of delivering CO to biological targets. Two ruthenium carbonyl complexes, namely trans-dicarbonyldichlorido(4,5-diazafluoren-9-one-κ(2)N,N')ruthenium(II), [RuCl2(C11H6N2O)(CO)2], (1), and fac-tricarbonyldichlorido(4,5-diazafluoren-9-one-κN)ruthenium(II), [RuCl2(C11H6N2O)(CO)3], (2), have been isolated and structurally characterized. In the case of complex (1), the trans-directing effect of the CO ligands allows bidentate coordination of the 4,5-diazafluoren-9-one (dafo) ligand despite a larger bite distance between the N-donor atoms. In complex (2), the cis disposition of two chloride ligands restricts the ability of the dafo molecule to bind ruthenium in a bidentate fashion. Both complexes exhibit well defined (1)H NMR spectra confirming the diamagnetic ground state of Ru(II) and display a strong absorption band around 300 nm in the UV.

  10. In tandem or alone: a remarkably selective transfer hydrogenation of alkenes catalyzed by ruthenium olefin metathesis catalysts.

    Science.gov (United States)

    Zieliński, Grzegorz Krzysztof; Samojłowicz, Cezary; Wdowik, Tomasz; Grela, Karol

    2015-03-07

    A system for transfer hydrogenation of alkenes, composed of a ruthenium metathesis catalyst and HCOOH, is presented. This operationally simple system can be formed directly after a metathesis reaction to effect hydrogenation of the metathesis product in a single-pot. These hydrogenation conditions are applicable to a wide range of alkenes and offer remarkable selectivity.

  11. Stability of Technetium and Decontamination from Ruthenium and Molybdenum in Determination of 99Tc in Environmental Solid Samples by ICPMS

    DEFF Research Database (Denmark)

    Shi, Keliang; Hou, Xiaolin; Roos, Per

    2012-01-01

    . The decontamination factors of more than 4 × 104 and 1 × 105 are achieved for molybdenum and ruthenium, respectively. Chemical yields of technetium in entire procedure range from 60% to 95% depending on the type and amount of samples, and the detection limit of 0.15 mBq/g for 99Tc was obtained. The method has been...

  12. The thermodynamic effects of ligand structure on the molecular recognition of mononuclear ruthenium polypyridyl complexes with B-DNA

    Science.gov (United States)

    The ruthenium(II) polypyridyl complexes (RPCs), [(phen)2Ru(tatpp)]Cl2 (3Cl2) and [(phen)2Ru (tatpp)Ru(phen)2]Cl4 (4Cl4), containing the large planar and redox-active tetraazatetrapyrido- pentacene (tatpp) ligand, cleave DNA in the presence of reducing agents in cell-free assays and show significant...

  13. Ruthenium hydride-catalyzed regioselective addition of benzaldehyde to dienes leading to β,γ-unsaturated ketones: a DFT study.

    Science.gov (United States)

    Meng, Qingxi; Wang, Fen; Li, Ming

    2012-12-01

    Density functional theory (DFT) was used to investigate the ruthenium hydride-catalyzed regioselective addition reactions of benzaldehyde to isoprene leading to the branched β,γ-unsaturated ketone. All intermediates and the transition states were optimized completely at the B3LYP/6-31 G(d,p) level (LANL2DZ(f) for Ru, LANL2DZ(d) for P and Cl). Calculated results indicated that three catalysts RuHCl(CO)(PMe(3))(3) (1), RuH(2)(CO)(PMe(3))(3) (2), and RuHCl(PMe(3))(3) (3) exhibited different catalysis, and the first was the most excellent. The most favorable reaction pathway included the coordination of 1 to the less substituted olefin of isoprene, a hydrogen transfer reaction from ruthenium to the carbon atom C1, the complexation of benzaldehyde to ruthenium, the carbonyl addition, and the hydride elimination reaction. The carbonyl addition was the rate-determining step. The dominant product was the branched β,γ-unsaturated ketone. Furthermore, the presence of one toluene molecule lowered the activation free energy of the transition state of the carbonyl addition by hydrogen bonds between the protons of toluene and the chlorine, carbonyl oxygen of the ruthenium complex. On the whole, the solvent effect decreased the free energies of the species.

  14. Hydrogenation of fast pyrolyis oil and model compounds in a two-phase aqueous organic system using homogeneous ruthenium catalysts

    NARCIS (Netherlands)

    Mahfud, F. H.; Ghijsen, F.; Heeres, H. J.

    2007-01-01

    The use of homogeneous ruthenium catalysts to hydrogenate the water-soluble fraction of pyrolysis oil is reported. Pyrolysis oil, which is obtained by fast pyrolysis of lignocellulosic biomass at 450-600 degrees C, contains significant amounts of aldehydes and ketones (e.g. 1-hydroxy-2-propanone (1)

  15. Straightforward synthesis of alpha,beta-unsaturated thioesters via ruthenium-catalyzed olefin cross-metathesis with thioacrylate

    NARCIS (Netherlands)

    van Zijl, Anthoni W.; Minnaard, Adriaan J.; Feringa, Ben L.

    2008-01-01

    The cross-metathesis reaction of S-ethyl thioacrylate with a variety of olefins is effectively catalyzed by using a ruthenium benzylidene olefin metathesis catalyst. This reaction provides a convenient and versatile route to substituted alpha,beta-unsaturated thioesters, key building blocks in

  16. Dehydrogenative Synthesis of Carboxylic Acids from Primary Alcohols and Hydroxide Catalyzed by a Ruthenium N-Heterocyclic Carbene Complex

    DEFF Research Database (Denmark)

    Santilli, Carola; Makarov, Ilya; Fristrup, Peter

    2016-01-01

    Primary alcohols have been reacted with hydroxide and the ruthenium complex [RuCl2(IiPr)(p-cymene)] to afford carboxylic acids and dihydrogen. The dehydrogenative reaction is performed in toluene, which allows for a simple isolation of the products by precipitation and extraction...

  17. Determination of ruthenium in photographic emulsions - Development and comparison of different sample treatments and mass spectrometric methods

    NARCIS (Netherlands)

    Krystek, Petra; Heumann, Klaus G.

    1999-01-01

    Different sample treatment procedures were combined with inductively coupled plasma mass spectrometry (ICP-MS) and negative thermal ionisation mass spectrometry (NTI-MS) for the determination of ruthenium traces in photographic emulsions. Dissolution of the samples in concentrated ammonia solution

  18. Bottom-Up Design of a Copper-Ruthenium Nanoparticulate Catalyst for Low-Temperature Ammonia Oxidation

    DEFF Research Database (Denmark)

    Chakraborty, Debasish; Damsgaard, Christian Danvad; Silva, Hugo José Lopes

    2017-01-01

    A novel nanoparticulate catalyst of copper (Cu) and ruthenium (Ru) was designed for low-temperature ammonia oxidation at near-stoichiometric mixtures using a bottom-up approach. A synergistic effect of the two metals was found. An optimum CuRu catalyst presents a reaction rate threefold higher than...

  19. Ruthenium nanoparticles decorated curl-like porous carbons for high performance supercapacitors

    Science.gov (United States)

    Lou, Bih-Show; Veerakumar, Pitchaimani; Chen, Shen-Ming; Veeramani, Vediyappan; Madhu, Rajesh; Liu, Shang-Bin

    2016-01-01

    The synthesis of highly dispersed and stable ruthenium nanoparticles (RuNPs; ca. 2-3 nm) on porous activated carbons derived from Moringa Oleifera fruit shells (MOC) is reported and were exploited for supercapacitor applications. The Ru/MOC composites so fabricated using the biowaste carbon source and ruthenium acetylacetonate as the co-feeding metal precursors were activated at elevated temperatures (600-900 oC) in the presence of ZnCl2 as the pore generating and chemical activating agent. The as-prepared MOC carbonized at 900 oC was found to possess a high specific surface area (2522 m2 g-1) and co-existing micro- and mesoporosities. Upon incorporating RuNPs, the Ru/MOC nanocomposites loaded with modest amount of metallic Ru (1.0-1.5 wt%) exhibit remarkable electrochemical and capacitive properties, achiving a maximum capacitance of 291 F g-1 at a current density of 1 A g-1 in 1.0 M H2SO4 electrolyte. These highly stable and durable Ru/MOC electrodes, which can be facily fabricated by the eco-friendly and cost-effective route, should have great potentials for practical applications in energy storage, biosensing, and catalysis.

  20. Conformations of N-Heterocyclic Carbene Ligands in Ruthenium Complexes Relevant to Olefin Metathesis

    Science.gov (United States)

    Stewart, Ian C.; Benitez, Diego; O'Leary, Daniel J.; Tkatchouk, Ekaterina; Day, Michael W.; Goddard, William A.; Grubbs, Robert H.

    2009-01-01

    The structure of ruthenium-based olefin metathesis catalyst 3 and model π-complex 5 in solution and in the solid state are reported. The N-tolyl ligands, due to their lower symmetry than the traditional N-mesityl substituents, complicate this analysis, but ultimately provide explanation for the enhanced reactivity of 3 relative to standard catalyst 2. The tilt of the N-tolyl ring provides additional space near the ruthenium center, which is consistent with the enhanced reactivity of 3 towards sterically demanding substrates. Due to this tilt, the more sterically accessible face bears the two methyl substituents of the N-aryl rings. These experimental studies are supported by computational studies of these complexes by DFT. The experimental data provides a means to validate the accuracy of the B3LYP and M06 functionals. B3LYP provides geometries that match X-ray crystal structural data more closely, though it leads to slightly less (∼0.5 kcal mol−1) accuracy than M06 most likely because it underestimates attractive non-covalent interactions. PMID:19146414

  1. Ruthenium acetylacetonate in interface engineering for high performance planar hybrid perovskite solar cells.

    Science.gov (United States)

    Chen, Wei; Luo, Shiqiang; Wan, Zunyuan; Feng, Xiyuan; Liu, Xinke; He, Zhubing

    2017-04-17

    As it already made huge effect in the commercialization of silicon and other photovoltaics, interface engineering is dispensable in the current and future evolution of hybrid perovskite solar cells (PSCs) techniques. In order to solve carriers' recombination and detention at the cathode side of planar PSCs, in this work, Ruthenium acetylacetonate (RuAcac) was successfully adopted as a reliable and stable cathode interfacial layer (CIL) to improve the inverted planar PSCs. The power conversion efficiency of the optimal devices was enhanced from 12.74% for the control device without RuAcac, to 17.15% for the RuAcac based devices, with an open circuit voltage of 1.077 V, a short circuit current density of 21.28 mA/cm2, and fill factor of 74.7% correspondingly. A series of photon-physics and microscopy protocols, including EQE, UPS, XPS, PL and SKPM, were used to discover the function of RuAcac CIL. Those results confirms an identical conclusion that RuAcac enables the formation of quasi-ohmic contact at the cathode side by eliminating the energy level barrier between the LUMO of PCBM and Fermi level of silver electrode. The low temperature and facile processed Ruthenium acetylacetonate in this work definitely offer us a robust interface-engineering way for the perovskite solar cells and also their commercialization.

  2. Arene control over thiolate to sulfinate oxidation in albumin by organometallic ruthenium anticancer complexes.

    Science.gov (United States)

    Hu, Wenbing; Luo, Qun; Ma, Xiaoyan; Wu, Kui; Liu, Jianan; Chen, Yi; Xiong, Shaoxiang; Wang, Jianping; Sadler, Peter J; Wang, Fuyi

    2009-07-06

    Interactions of organometallic ruthenium anticancer complexes [Ru(eta6-arene)Cl(en)][PF6] (arene=p-cymene (1) or biphenyl (2), en=ethylenediamine) with human serum albumin were investigated by means of mass spectrometry combined with trypsin digestion, specific sidechain modifications and computational modelling. Both complexes were shown to bind to surface histidine (His128, His247, His510) and methionine (Met298) residues in human albumin, but only the p-cymene complex can gain entry to the crevice containing the free cysteine thiolate (Cys34) and induce oxidation to sulfinate. The two complexes exhibit a similar coordination preference for histidine and methionine residues on the protein surface. His128 binding is favoured both kinetically and thermodynamically. At 310 K, six days of incubation of recombinant human albumin (rHA) with complex 1 (rHA:Ru 50:250 microM) led to about 18 % ruthenation of His128 in the protein. However, the extent of ruthenation of albumin by complex 2 was less than that by 1, due to the steric hindrance from the biphenyl ligand. These results imply that the arene ligand in the organometallic ruthenium anticancer complexes plays a crucial role in interactions with proteins.

  3. Structural and catalytic properties of some azo-rhodanine Ruthenium(III) complexes

    Science.gov (United States)

    Shoair, A. F.; El-Bindary, A. A.; Abd El-Kader, M. K.

    2017-09-01

    Novel azo-rhodanine ruthenium(III) complexes of the type trans-[Ru(Ln)2(AsPh3)2]Cl (Ln = monobasic bidentate anions of 5-(4‧-methoxyphenylazo)-3-phenylamino-2-thioxothiazolidin-4-one (HL1), 5-(phenylazo)-3-phenylamino-2-thioxothiazolidin-4-one (HL2) and 5-(4‧-chlorophenylazo)-3-phenylamino-2-thioxothiazolidin-4-one (HL3); AsPh3 = triphenylarsine) have been synthesized and characterized by elemental analysis, spectroscopic (IR, 1H NMR and UV-VIS), magnetic, X-ray diffraction, mass spectra and thermal analysis techniques. These techniques confirm the formation of octahedral ruthenium(III) complexes. The Ru(III) complexes were tested as a catalysts for the oxidation of benzyl alcohol to benzaldehyde with N-methylmorpholine-N-oxide as a co-oxidant. The effect of time, temperature, and solvent were also studied and the mechanism of this catalytic oxidation reaction is suggested. Molecular docking was used to predict the binding between azo rhodanine derivatives (HLn) with the receptor of 3qum- immune system receptor of human prostate specific antigen (PSA) in a Fab sandwich with a high affinity and a PCa selective antibody.

  4. Synthesis and Application of Novel Ruthenium Catalysts for High Temperature Alkene Metathesis

    Directory of Open Access Journals (Sweden)

    Tegene T. Tole

    2017-01-01

    Full Text Available Four pyridinyl alcohols and the corresponding hemilabile pyridinyl alcoholato ruthenium carbene complexes of the Grubbs second generation-type RuCl(H2IMes(O^N(=CHPh, where O^N = 1-(2′-pyridinyl-1,1-diphenyl methanolato, 1-(2′-pyridinyl-1-(2′-chlorophenyl,1-phenyl methanolato, 1-(2′-pyridinyl-1-(4′-chlorophenyl,1-phenyl methanolato and 1-(2′-pyridinyl-1-(2′-methoxyphenyl,1-phenyl methanolato, are synthesized in very good yields. At high temperatures, the precatalysts showed high stability, selectivity and activity in 1-octene metathesis compared to the Grubbs first and second generation precatalysts. The 2-/4-chloro- and 4-methoxy-substituted pyridinyl alcoholato ligand-containing ruthenium precatalysts showed high performance in the 1-octene metathesis reaction in the range 80–110 °C. The hemilabile 4-methoxy-substituted pyridinyl alcoholato ligand improved the catalyst stability, activity and selectivity for 1-octene metathesis significantly at 110 °C.

  5. Application of the ruthenium and technetium thermodynamic data bases used in the EQ3/6 geochemical codes

    Energy Technology Data Exchange (ETDEWEB)

    Isherwood, D.

    1985-04-01

    Based on a critical review of the available thermodynamic data, computerized data bases for technetium and ruthenium were created for use with the EQ3/6 geochemical computer codes. The technetium data base contains thermodynamic data for 8 aqueous species and 15 solids; 26 aqueous species and 9 solids were included in the ruthenium data base. The EQ3NR code was used to calculate solubility limits for ruthenium (8 x 10{sup -16} M) in ground water from Yucca Mountain, a potential nuclear waste repository site near the Nevada Test Site (NTS). The code confirmed the essentially unlimited solubility of technetium in oxidizing conditions, such as those that are believed to exist in the unsaturated zone at Yucca Mountain and the Cambric Nuclear event site at the NTS. Ruthenium migration observed from the Cambric site was evaluated. The solubility limit for ruthenium (as the aqueous species RuO{sub 4}{sup -}) when constrained by RuO{sub 2} is approximately equal to the concentration of ruthenium found in the cavity ground water (i.e., 2.1 x 10{sup -11} vs 4.5 x 10{sup -11} M). Differences in ruthenium solubility limits between Yucca Mountain and Cambric are primarily due to differences in ground-water pH. Technetium solubility (3 x 10{sup -8} M) for moderately reducing conditions (Eh = -0.1 V) using the metastable oxide, TcO{sub 2}.2H{sub 2}O, as the solubility constraint is within the range of experimental values recently published in a study of technetium sorption on basalt. Previously published technetium solubilities of 10{sup -12} to 10{sup -16} M were apparently based on a technetium data base that did not include aqueous species other than TcO{sub 4}{sup -}. When TcO(OH){sub 2}{sup 0} is included in the data base, the calculated values are much closer to the experimental results. Eh-pH diagrams were also generated for a variety of conditions using the SOLUPLOT code.

  6. Effect of repeated cycles of chemical disinfection on the roughness and hardness of hard reline acrylic resins.

    Science.gov (United States)

    Pinto, Luciana de Rezende; Acosta, Emílio José T Rodríguez; Távora, Flora Freitas Fernandes; da Silva, Paulo Maurício Batista; Porto, Vinícius Carvalho

    2010-06-01

    The aim of this study was to assess the effect of repeated cycles of five chemical disinfectant solutions on the roughness and hardness of three hard chairside reliners. A total of 180 circular specimens (30 mm x 6 mm) were fabricated using three hard chairside reliners (Jet; n = 60, Kooliner; n = 60, Tokuyama Rebase II Fast; n = 60), which were immersed in deionised water (control), and five disinfectant solutions (1%, 2%, 5.25% sodium hypochlorite; 2% glutaraldehyde; 4% chlorhexidine gluconate). They were tested for Knoop hardness (KHN) and surface roughness (microm), before and after 30 simulated disinfecting cycles. Data was analysed by the factorial scheme (6 x 2), two-way analysis of variance (anova), followed by Tukey's test. For Jet (from 18.74 to 13.86 KHN), Kooliner (from 14.09 to 8.72 KHN), Tokuyama (from 12.57 to 8.28 KHN) a significant decrease in hardness was observed irrespective of the solution used on all materials. For Jet (from 0.09 to 0.11 microm) there was a statistically significant increase in roughness. Kooliner (from 0.36 to 0.26 microm) presented a statistically significant decrease in roughness and Tokuyama (from 0.15 to 0.11 microm) presented no statistically significant difference after 30 days. This study showed that all disinfectant solutions promoted a statistically significant decrease in hardness, whereas with roughness, the materials tested showed a statistically significant increase, except for Tokuyama. Although statistically significant values were registered, these results could not be considered clinically significant.

  7. Carbon Equivalent and Maximum Hardness

    OpenAIRE

    Haruyoshi, Suzuki; Head Office, Nippon Steel Corporation

    1984-01-01

    The accuracy of formulae for estimating the maximum hardness values of the HAZ from chemical composition and cooling time for welds in high strength steel is discussed and a new formula. NSC-S, is proposed which uses only C%, Pcm% and cooling time for the purpose of satisfactory accuracy. IIW CE and Ito-Bessyo Pcm carbon equivalent alone are not satisfactory in establishing Hmax values. The former is good only for slow cooling, t8/5 longer than 10 seconds, while the latter is good only for fa...

  8. Hard Identity and Soft Identity

    Directory of Open Access Journals (Sweden)

    Hassan Rachik

    2006-04-01

    Full Text Available Often collective identities are classified depending on their contents and rarely depending on their forms. Differentiation between soft identity and hard identity is applied to diverse collective identities: religious, political, national, tribal ones, etc. This classification is made following the principal dimensions of collective identities: type of classification (univocal and exclusive or relative and contextual, the absence or presence of conflictsof loyalty, selective or totalitarian, objective or subjective conception, among others. The different characteristics analysed contribute to outlining an increasingly frequent type of identity: the authoritarian identity.

  9. The hardness of synthetic products obtained from cooled and crystallized basaltic melts (in Romanian

    Directory of Open Access Journals (Sweden)

    Daniela Ogrean

    2001-04-01

    Full Text Available The Hardness of Synthetic Products Obtained from Cooled and Crystallized Basaltic Melts. Hardness is one of the main properties of the products obtained from cooled and crystallized basaltic melts under a controlled thermal regime. It influences the abrasion tear resistance of the resulted material. The microhardness measurements on the samples (bricks, boards, gutters, armour plates, tubes indicated Vickers hardness value between 757–926 for the materials obtained from Şanovita basalts (Timiş district and between 539–958 respectively, in case of the Racoş basalts (Braşov district. There is a certain variation of the hardness within the same sample, in various measurement points, within the theoretical limits of the hardnesses of the pyroxenes and that of the spinels.

  10. Synthesis and Characterization of Platinum-Ruthenium-Tin Catalysts

    Science.gov (United States)

    Uffalussy, Karen

    Magnesia-supported trimetallic Pt-Ru-Sn catalysts prepared through a cluster and a conventional synthetic route have been investigated in terms of their structural properties and their catalytic activity for the hydrogenation of citral and crotonaldehyde. FTIR results indicate that the majority of the stabilizing ligands remain attached to the PtRu5(μ-SnPh 2)(C)(CO)15 cluster used following impregnation onto the MgO support. Under H2 reduction conditions, partial and full ligand removal are both observed at 473 and 573 K, respectively. HRSTEM analysis shows that cluster-derived samples exhibit significantly smaller average metal particle sizes, as well as narrower particle size distributions than the corresponding conventionally prepared ones. EDX measurements show that in the cluster-derived catalysts, the majority of the metal particles present are trimetallic in nature, with metal compositions similar to those of the original cluster. In contrast, the conventionally prepared materials contain mostly bimetallic and monometallic particles with variable compositions. XPS was used to determine how the variation in method of Sn addition to bimetallic Pt-Ru affects the electronic state for the trimetallic Pt-Ru-Sn/MgO system prepared by impregnation using multimetallic clusters, metal-salts, and the combination of both precursor types. Results show that the PtRu5Sn/MgO material has a significantly higher percentage of Sn0 in comparison to Pt-Ru-Sn/MgO and PtRu5-Sn/MgO, and a corresponding shift in both Pt and Ru peaks can be correlated to this relative change in Sn oxidation state. The formation of smaller metal particles and electronic modification of Pt and Ru by Sn in the cluster-derived catalysts and the presence of the three metals in these particles in close proximity result in higher activity and selectivity to the unsaturated alcohols for the hydrogenation of both citral and crotonaldehyde.

  11. Dialkylmethyl-2-(N,N-diisobutyl)acetamidoammonium iodide as a ruthenium selective ligand from nitric acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Shikha [Bio-Organic Division, Bhabha Atomic Research Center, Trombay, Mumbai 400085 (India); Ghosh, Sunil K., E-mail: ghsunil@barc.gov.in [Bio-Organic Division, Bhabha Atomic Research Center, Trombay, Mumbai 400085 (India); Sharma, Joti N., E-mail: jnsharma@barc.gov.in [Process Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2015-09-15

    Highlights: • A new class of quart-ammonium based ligands have been designed and synthesized. • Ligand showed high extractability and selectivity for Ru in nitric acid medium. • Results are better compared to other extractants reported so far. • The iodide ion played key role in extraction process. • The composition of the extracted complex was found to be L[Ru(NO)(NO{sub 3}){sub 3}I]. - Abstract: A new class of quaternary ammonium iodide based ligands with 2-(N,N-diisobutyl)acetamide as an alkyl appendage have been designed, synthesized and tested for their ability to extract ruthenium selectively from nitric acid medium. The 2-(N,N-diisobutyl)acetamido ammonium iodide with two propyl and a methyl substituents showed best results for the recovery of ruthenium. The optimized concentration of the solvent was found to be 0.2 M in 30% isodecyl alcohol/n-dodecane. The stoichiometry of the complex was ascertained by slope analysis method and was found to be 1:1 with respect to ligand L{sup +}I{sup −} and Ru(NO)(NO{sub 3}){sub 3}. Ruthenium formed an adduct of structure LRu(NO)(NO{sub 3}){sub 3}I in the extraction medium. Iodide ion played an important role in the formation of the stable and extractable complex of ruthenium. No extraction was observed when iodide was replaced by nitrate anion in the ligand. The ligand also showed good selectivity for ruthenium in the presence of other metal ions commonly found in nitric acid solutions of nuclear waste.

  12. Evaluation of the Various Drying Methods on Surface Hardness of Type IV Dental Stone

    OpenAIRE

    Sudhakar, A.; Srivatsa, G.; Shetty, Rohit; Rajeswari, C L; Manvi, Supriya

    2015-01-01

    Background: Studies regarding the effect of various methods to increase the surface hardness of Type IV dental stone are not conclusive. Therefore, this study was carried out to evaluate the effect of air drying, micro oven drying and die hardener on surface hardness of Type IV dental stone. Materials and Methods: A standard metal die was fabricated; polyvinyl siloxane impression material was used to make the molds of metal die. A total of 120 specimens were obtained from two different die st...

  13. Effect of cooling rate on the microstructure and hardness of austenitic stainless steel welds

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, A. [ISEC - IPC, Quinta da Nora, Coimbra (Portugal); Loureiro, A. [DEM - FCTUC, Polo II, Coimbra (Portugal)

    2004-07-01

    The aim of this work is to study the effect of the cooling rate on the microstructure and hardness of the melted material of welds in steels AISI 304 and AISI 316L. The increase of weld heat input, consequently the decrease in the cooling rate, produces only a smooth increase of the ferrite content and a small decrease of hardness in the melted material of autogeneous TIG welds. (orig.)

  14. ASSOCIATION BETWEEN RETINAL HARD EXUDATES AND DYSLIPIDEMIA IN TYPE 2 DIABETIC PATIENTS IN RURAL KARNATAKA

    Directory of Open Access Journals (Sweden)

    Arun Kumar B.

    2015-10-01

    Full Text Available AIM: To evaluate the association of elevated serum lipids with retinal hard exudates in type 2 diabetic patients in rural Karnataka. MATERIAL AND METHODS : Hospital based cross sectional study which included 60 (n=60 type 2 diabetic patients (60 eyes fulfilling the inclusion criteria. Patients were subjected to detailed ocular examination, fundus examination done under full dilatation using indirect ophth almoscope with 20D lens and slit lamp biomicroscope with 90D lens. Fundus photographs were obtained using fundus camera. Grading of retinal hard exudates performed by utilizing modified Airlie House classification. The modified Airlie House Classification used is as follows: Grade 0 - No evidence of hard exudates; Grade 1 : Questionable hard exudates present; Grade 2 : Hard exudates less than standard photograph 3; Grade 3 : Hard exudates greater than or equal to standard photograph 3, but less than standard p hotograph 5; Grade 4 : Hard exudates greater than or equal to standard photograph 5, but less than standard photograph 4 and Grade 5 : Hard exudates greater than or equal to standard photograph 4. These grades were further divided into three groups of patie nt severity as follows: Group 1 (absent or minimal hard exudates included patients with Grade 0, 1 or 2 hard exudates; Group 2 (hard exudates present included patients with Grade 3 or 4 hard exudates and Group 3 (prominent hard exudates included patient s with Grade 5 hard exudates. Fasting lipid profile including serum total cholesterol, low density lipoproteins, very low density lipoproteins, high density lipoproteins and triglycerides was obtained. Association of dyslipidemia with retinal hard exudates was analysed using one way ANOVA test. RESULTS: On statistical analysis with ANOVA test retinal hard exudates were significantly associated with elevated total cholesterol (p= .0001, triglycerides (p= .0001, serum LDL (p=.008, serum VLDL (p=.012, and negative correlation was found

  15. Ruthenium(II)-tris-bipyridine and titaniumdioxide - photocatalysts for solar induced water remediation; Ruthenium(II)-tris-bipyridin und Titandioxid - Photokatalysatoren zum solarinduzierten Abbau von Schadstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Bossmann, S. [Lehrstuhl fuer Umweltmesstechnik, Engler-Bunte-Inst., Karlsruhe Univ. (Germany)

    1997-01-01

    The photophysical and photochemical properties of photocatalysts capable of working under solar-light-irradiation are of great interest. An especially promising application is the development of low-cost `Advanced Oxidation Procedures` (AOP). The aim of this endeavor is the detoxification of hazardous chemicals in wastewaters, which cannot be treated by conventional techniques. The mineralization of the most (highly) toxic chemicals to CO{sub 2}, H{sub 2}O and simple inorganic compounds is favored by thermodynamics, however various difficulties such as kinetic barriers and hindered diffusion exist in systems for heterogeneous photocatalysis. In that respect, Ruthenium(II)-tris-bipyridine ([Ru(bpy){sub 3}]{sup 2+}) and TiO{sub 2} - codoped photocatalysts offer several advantages. The photoreactive centers consist of supramolecular units of [Ru(bpy){sub 3}]{sup 2+} and TiO{sub 2} - nanocrystals. Pollutants, such as our model compound 2,4-Dimethylaniline, diffuse through the framework of zeolite Y and undergo oxidative degradation at the reactive centers of the photocatalysts in the presence of H{sub 2}O{sub 2}. Under the aspect of application, the size of the zeolite Y-particles (diameter: 1x10{sup -6} m in average) permits their easy handling in filtration and recyling operations. (orig.) [Deutsch] Die photophysikalischen und -chemischen Eigenschaften von Katalysatoren, die das Licht der Sonne als kostenguenstige Energiequelle ausnutzen, treten immer staerker in den Vordergrund des Interesses. Dies gilt vor allem fuer ihren Einsatz in `Advanced Oxidation Technologies` (AOT`s) zur Entgiftung toxischer Substanzen im Abwasser. Die Mineralisation der meisten (hoch)giftigen Chemikalien zu CO{sub 2}, H{sub 2}O und einfachen anorganischen Verbindungen ist zwar thermodynamisch beguenstigt, es treten jedoch sowohl kinetische Hemmschwellen als auch Diffusionshindernisse in der heterogenen Photokatalyse auf. Ruthenium(II)-tris-bipyridin ([Ru(bpy){sub 3}]{sup 2+}) und TiO{sub 2

  16. High Electrocatalytic Hydrogen Evolution Activity of an Anomalous Ruthenium Catalyst.

    Science.gov (United States)

    Zheng, Yao; Jiao, Yan; Zhu, Yihan; Li, Lu Hua; Han, Yu; Chen, Ying; Jaroniec, Mietek; Qiao, Shi-Zhang

    2016-12-14

    Hydrogen evolution reaction (HER) is a critical process due to its fundamental role in electrocatalysis. Practically, the development of high-performance electrocatalysts for HER in alkaline media is of great importance for the conversion of renewable energy to hydrogen fuel via photoelectrochemical water splitting. However, both mechanistic exploration and materials development for HER under alkaline conditions are very limited. Precious Pt metal, which still serves as the state-of-the-art catalyst for HER, is unable to guarantee a sustainable hydrogen supply. Here we report an anomalously structured Ru catalyst that shows 2.5 times higher hydrogen generation rate than Pt and is among the most active HER electrocatalysts yet reported in alkaline solutions. The identification of new face-centered cubic crystallographic structure of Ru nanoparticles was investigated by high-resolution transmission electron microscopy imaging, and its formation mechanism was revealed by spectroscopic characterization and theoretical analysis. For the first time, it is found that the Ru nanocatalyst showed a pronounced effect of the crystal structure on the electrocatalytic activity tested under different conditions. The combination of electrochemical reaction rate measurements and density functional theory computation shows that the high activity of anomalous Ru catalyst in alkaline solution originates from its suitable adsorption energies to some key reaction intermediates and reaction kinetics in the HER process.

  17. High Electrocatalytic Hydrogen Evolution Activity of an Anomalous Ruthenium Catalyst

    KAUST Repository

    Zheng, Yao

    2016-11-28

    Hydrogen evolution reaction (HER) is a critical process due to its fundamental role in electrocatalysis. Practically, the development of high-performance electrocatalysts for HER in alkaline media is of great importance for the conversion of renewable energy to hydrogen fuel via photoelectrochemical water splitting. However, both mechanistic exploration and materials development for HER under alkaline conditions are very limited. Precious Pt metal, which still serves as the state-of-the-art catalyst for HER, is unable to guarantee a sustainable hydrogen supply. Here we report an anomalously structured Ru catalyst that shows 2.5 times higher hydrogen generation rate than Pt and is among the most active HER electrocatalysts yet reported in alkaline solutions. The identification of new face-centered cubic crystallographic structure of Ru nanoparticles was investigated by high-resolution transmission electron microscopy imaging, and its formation mechanism was revealed by spectroscopic characterization and theoretical analysis. For the first time, it is found that the Ru nanocatalyst showed a pronounced effect of the crystal structure on the electrocatalytic activity tested under different conditions. The combination of electrochemical reaction rate measurements and density functional theory computation shows that the high activity of anomalous Ru catalyst in alkaline solution originates from its suitable adsorption energies to some key reaction intermediates and reaction kinetics in the HER process.

  18. Robust binding between carbon nitride nanosheets and a binuclear ruthenium(II) complex enabling durable, selective CO{sub 2} reduction under visible light in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Kuriki, Ryo; Ishitani, Osamu; Maeda, Kazuhiko [Department of Chemistry, School of Science, Tokyo Institute of Technology (Japan); Yamamoto, Muneaki; Yoshida, Tomoko [Advanced Research Institute for Natural Science and Technology, Osaka City University (Japan); Higuchi, Kimitaka; Yamamoto, Yuta; Akatsuka, Masato; Yagi, Shinya [Institute of Materials and Systems for Sustainability, Nagoya University (Japan); Lu, Daling [Suzukakedai Materials Analysis Division, Technical Department, Tokyo Institute of Technology, Yokohama (Japan)

    2017-04-18

    Carbon nitride nanosheets (NS-C{sub 3}N{sub 4}) were found to undergo robust binding with a binuclear ruthenium(II) complex (RuRu') even in basic aqueous solution. A hybrid material consisting of NS-C{sub 3}N{sub 4} (further modified with nanoparticulate Ag) and RuRu' promoted the photocatalytic reduction of CO{sub 2} to formate in aqueous media, in conjunction with high selectivity (approximately 98 %) and a good turnover number (>2000 with respect to the loaded Ru complex). These represent the highest values yet reported for a powder-based photocatalytic system during CO{sub 2} reduction under visible light in an aqueous environment. We also assessed the desorption of RuRu' from the Ag/C{sub 3}N{sub 4} surface, a factor that can contribute to a loss of activity. It was determined that desorption is not induced by salt additives, pH changes, or photoirradiation, which partly explains the high photocatalytic performance of this material. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Methanol resistant ruthenium electrocatalysts for oxygen reduction synthesized by pyrolysis of Ru{sub 3}(CO){sub 12} in different atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Altamirano-Gutierrez, A.; Jimenez-Sandoval, O.; Uribe-Godinez, J.; Borja-Arco, E. [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional (Cinvestav), Unidad Queretaro, Apartado Postal 1-798, Queretaro, Qro. 76001 (Mexico); Castellanos, R.H. [Universidad del Papaloapan, Campus Tuxtepec, Circuito Central No. 200, Col. Parque Industrial, Tuxtepec, Oax. 68301 (Mexico); Olivares-Ramirez, J.M. [Universidad Tecnologica de San Juan del Rio, Av. La Palma No. 125, Col. Vista Hermosa, San Juan del Rio, Qro. 76800 (Mexico)

    2009-10-15

    Novel ruthenium electrocatalysts for the oxygen reduction reaction (ORR) were prepared by pyrolysis of Ru{sub 3}(CO){sub 12} in three atmospheres: neutral (N{sub 2}), partially oxidative (air) and partially reductive (70:30 N{sub 2}/H{sub 2}), at temperatures in the 80-700 C range. The materials were characterized by FT-IR spectroscopy, X-ray diffraction and scanning electron microscopy. A thermogravimetric analysis of the Ru{sub 3}(CO){sub 12} precursor in the three atmospheres was also performed. The electrocatalytic properties of the materials were evaluated by rotating disk electrode measurements in 0.5 mol L{sup -1} H{sub 2}SO{sub 4}. The kinetic parameters, such as the Tafel slope, exchange current density and charge transfer coefficient, are reported. The catalysts prepared in N{sub 2} and N{sub 2}/H{sub 2}, in general, show a higher performance than those synthesized in air. In the two nitrogen containing atmospheres, a pyrolysis temperature of 360 C seems to lead to better electrocatalytic properties for the ORR. The new electrocatalysts are also tolerant to methanol concentrations as high as 2.0 mol L{sup -1}. (author)

  20. Dynamic hardness of high-strength steel and titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Stepanov, G.; Zubov, V. [Natsional' na Akademyiya Ukrayini, Kiev (Ukraine). Inst. of Strength Problems

    2000-09-01

    Essential results of experimental studies on dynamic hardness (an average pressure on the cone face of a rigid rod at its impact indentation into the surface layer of a thick plate) of a homogeneous rolled steel (HRA) and a titanium alloy are presented in this paper. Significant influence of the impact velocity on dynamic hardness of materials tested follows from the analysis of the experimental data. Specific energy of the formation of a conical cavity (per unit volume of displaced material) decreases with an increase in the indentation velocity and the conical cavity depth. At further process of indentation, corresponding to the initial stage of penetration (the cavity depth exceeds the length of the rod conical head) the average pressure increases with the impact velocity. Combined influence of viscosity effect and rise in temperature at plastic flow should be taken into account in order to explain the above relations. (orig.)

  1. Hard X-ray Zone Plates Using Ultrananocrystalline Diamond Molds

    Science.gov (United States)

    Wojcik, M. J.; Joshi, V.; Sumant, A. V.; Divan, R.; Ocola, L. E.; Lu, M.; Mancini, D. C.

    2011-09-01

    While hard x-ray zone plates have made great advances recently towards improved resolution, their focusing efficiency requires further development. This problem becomes more important as higher-energy x-rays are used for x-ray microscopy. The current method for fabricating zone plates involves a dielectric mold, which is then electroplated into, but the materials used for this mold are not mechanically stiff enough for the zone plates desired. Ultrananocrystalline diamond (UNCD) is a form of diamond that can be grown as a thin film by chemical vapor deposition and offers many of the physical properties of bulk diamond. Its mechanical stiffness, resistance to radiation damage, dielectric properties, and ability to be etched suggests UNCD as a capable mold material. Reported is progress in the fabrication of hard x-ray zone plates with gold electroformed into a UNCD mold.

  2. A hard X-ray nanoprobe beamline for nanoscale microscopy.

    Science.gov (United States)

    Winarski, Robert P; Holt, Martin V; Rose, Volker; Fuesz, Peter; Carbaugh, Dean; Benson, Christa; Shu, Deming; Kline, David; Stephenson, G Brian; McNulty, Ian; Maser, Jörg

    2012-11-01

    The Hard X-ray Nanoprobe Beamline (or Nanoprobe Beamline) is an X-ray microscopy facility incorporating diffraction, fluorescence and full-field imaging capabilities designed and operated by the Center for Nanoscale Materials and the Advanced Photon Source at Sector 26 of the Advanced Photon Source at Argonne National Laboratory. This facility was constructed to probe the nanoscale structure of biological, environmental and material sciences samples. The beamline provides intense focused X-rays to the Hard X-ray Nanoprobe (or Nanoprobe) which incorporates Fresnel zone plate optics and a precision laser sensing and control system. The beamline operates over X-ray energies from 3 to 30 keV, enabling studies of most elements in the periodic table, with a particular emphasis on imaging transition metals.

  3. Tumor parameters predict the risk of side effects after ruthenium-106 plaque brachytherapy of uveal melanomas.

    Directory of Open Access Journals (Sweden)

    Lisa Tarmann

    Full Text Available To report on radiation-related side effects and complications after ruthenium-106 plaque brachytherapy of uveal melanomas.Medical records of 143 eyes with uveal melanoma, treated by ruthenium-106 brachytherapy between 1997 and 2012 at a single center, were analyzed. We evaluated the occurrence of radiation-related side effects on the anterior and posterior segment of the eye. The influence of patient, tumor and treatment parameters on outcome was analyzed by multivariate time to event analysis considering competing risks.The median overall follow-up was 37.9 months. After treatment, the estimated risk at 12, 24 and 48 months for developing anterior segment complications was 25.3%, 37.5% and 50.3% for cataract formation and 5.4%, 6.4% and 8.1% for secondary glaucoma, respectively. The estimated risk for the occurrence of posterior segment complications 12, 24 and 48 months after treatment was 3.1%, 6.7% and 18.3% for radiation retinopathy, 18.3%, 27.1% and 42.6% for radiation maculopathy and 16.5%, 21.0% and 32.8% for radiation neuropathy, respectively. The risk of an increase in retinal detachment after treatment was 14.7%, 14.7% and 17.4% at 12, 24 and 48 months, respectively. The risk of vitreous hemorrhage occurring after treatment was 6.2%, 8.1% and 12.7%, and the risk of tumor vasculopathy was 15.4%, 17.4% and 19.0%. Scleral necrosis was observed in one patient.Radiation-related side effects and complications are common among patients treated with ruthenium brachytherapy for uveal melanoma. However, the risk for those largely depends on individual tumor parameters. Before treatment, patients should be informed of their specific risks to develop various side effects. Patient information before treatment should cover not only general information about the treatment and possible complications and side effects but should also give details on the specific risks of the patient in her individual situation. This also includes elucidating the

  4. Elastic modulus of hard tissues.

    Science.gov (United States)

    Bar-On, Benny; Wagner, H Daniel

    2012-02-23

    This work aims at evaluating the elastic modulus of hard biological tissues by considering their staggered platelet micro-structure. An analytical expression for the effective modulus along the stagger direction is formulated using three non-dimensional structural variables. Structures with a single staggered hierarchy (e.g. collagen fibril) are first studied and predictions are compared with the experimental results and finite element simulations from the literature. A more complicated configuration, such as an array of fibrils, is analyzed next. Finally, a mechanical model is proposed for tooth dentin, in which variations in the multi-scale structural hierarchy are shown to significantly affect the macroscopic mechanical properties. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Infinite hard-sphere system

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, R.K.

    1975-09-01

    The time-evolution for the system of infinitely many particles in space interacting by a hard-sphere potential is constructed. Examples abound of configurations of the infinite system having more than one solution to the Newtonian equations of motion. A regularity condition is imposed on the solutions sought, which limits the growth of velocities and of the length of chains of particles close together as absolute value x ..-->.. infinity; it is proven that through any point of the phase space there passes at most one regular solution. Every point in a subset X bar of the phase space X is the initial point of a regular solution which is defined for all time. The subset X bar is of full measure for every Gibbs state and is invariant under the one-parameter group T/sup t/ of shifts along solution trajectories. Moreover, the flow T/sup t/ leaves every Gibbs state invariant. The solutions constructed are limits, as R ..-->.. infinity, of motions in which particles inside the sphere of radius R are elastically reflected from its boundary while those outside remain fixed. For this reason, one also studies the motion of finite systems. For finitely many hard-sphere particles in a region of space with piecewise smooth boundary, the set of points of the phase space through which solutions exist for all time without triple or grazing collisions, are of full Lebesgue measure and are residual in the sense of Baire. Liouville's Theorem holds for the one-parameter group of shift-transformations T/sup t/. Finally, we give examples in which a single billiard moving in the plane is reflected infinitely often from a boundary curve in finite time, and necessary conditions for such singularities to occur are established.

  6. Outer-sphere 2 e{sup -}/2 H{sup +} transfer reactions of ruthenium(II)-amine and ruthenium(IV)-amido complexes

    Energy Technology Data Exchange (ETDEWEB)

    Cattaneo, Mauricio [Department of Chemistry, University of Washington (United States); INQUINOA-CONICET, Universidad Nacional de Tucuman, San Miguel de Tucuman (Argentina); Ryken, Scott A. [Department of Chemistry, University of Washington (United States); Mayer, James M. [Department of Chemistry, University of Washington (United States); Department of Chemistry, Yale University, New Haven, CT, 06520 (United States)

    2017-03-20

    A diverse set of 2 e{sup -}/2 H{sup +} reactions are described that interconvert [Ru{sup II}(bpy)(en*){sub 2}]{sup 2+} and [Ru{sup IV}(bpy)(en-H*){sub 2}]{sup 2+} (bpy=2,2'-bipyridine, en*=H{sub 2}NCMe{sub 2}CMe{sub 2}NH{sub 2}, en*-H=H{sub 2}NCMe{sub 2}CMe{sub 2}NH{sup -}), forming or cleaving different O-H, N-H, S-H, and C-H bonds. The reactions involve quinones, hydrazines, thiols, and 1,3-cyclohexadiene. These proton-coupled electron transfer reactions occur without substrate binding to the ruthenium center, but instead with precursor complex formation by hydrogen bonding. The free energies of the reactions vary over more than 90 kcal mol{sup -1}, but the rates are more dependent on the type of X-H bond involved than the associated ΔG . There is a kinetic preference for substrates that have the transferring hydrogen atoms in close proximity, such as ortho-tetrachlorobenzoquinone over its para-isomer and 1,3-cyclohexadiene over its 1,4-isomer, perhaps hinting at the potential for concerted 2 e{sup -}/2 H{sup +} transfers. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. A new approach to local hardness

    CERN Document Server

    Gal, T; De Proft, F; Torrent-Sucarrat, M

    2011-01-01

    The applicability of the local hardness as defined by the derivative of the chemical potential with respect to the electron density is undermined by an essential ambiguity arising from this definition. Further, the local quantity defined in this way does not integrate to the (global) hardness - in contrast with the local softness, which integrates to the softness. It has also been shown recently that with the conventional formulae, the largest values of local hardness do not necessarily correspond to the hardest regions of a molecule. Here, in an attempt to fix these drawbacks, we propose a new approach to define and evaluate the local hardness. We define a local chemical potential, utilizing the fact that the chemical potential emerges as the additive constant term in the number-conserving functional derivative of the energy density functional. Then, differentiation of this local chemical potential with respect to the number of electrons leads to a local hardness that integrates to the hardness, and possesse...

  8. The hardness and sliding wear behaviour of a bainitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Shipway, P.H. [Nottingham Univ. (United Kingdom). Dept. of Materials Engineering and Materials Design; Wood, S.J. [Nottingham Univ. (United Kingdom). Dept. of Materials Engineering and Materials Design; Dent, A.H. [Nottingham Univ. (United Kingdom). Dept. of Materials Engineering and Materials Design

    1997-03-01

    High-strength bainitic steels have a number of desirable mechanical properties and have thus been viewed as candidate materials for heavy wear applications. This work examines the role of transformation temperature on the wear resistance of isothermally formed bainite from a single alloy steel and compares it with wear resistance following other heat treatments such as quenching, quenching and tempering and normalisation. The sliding wear resistance was examined for a range of applied loads at a constant sliding velocity of 1 m s{sup -1}. Microstructural constituents of the steels were related to their wear resistance. The hardness of the bainitic steel was a function of the isothermal transformation temperature and its variation has been correlated with the transformation behaviour. However, the hardness of the materials did not correlate well with their wear resistance, with the hardest martensitic steel showing greater wear rates than the normalised steel. Bainitic microstructures formed at low transformation temperatures were found to have a high wear resistance which in many cases was a factor of two better than any of the other microstructures examined; this material had a good combination of hardness and toughness on the microstructural level due to the fine nature of the bainite formed with high dislocation density and the lack of embrittling martensite and cementite phases and it is proposed that these attributes confer its high wear resistance. (orig.)

  9. DN Hard Materials Laser Assisted Formation of Dense Phases

    Science.gov (United States)

    1991-01-14

    a and 0 carbynes, chaoite, lonsdaleite , and dia- of the experimental set-up is shown in Fig. 1. The mond. The separation of the transformed high-pres...crystalline and con- tained graphite, chaoite, and diamond particles. No a or 0 carbynes or lonsdaleite particles were ob- served in the TEM study. Again...Fedoseev et a.[ 13] pointed out that the presence of lonsdaleite was not Fig. I. Schematic diagram of the experimental set-up. unambiguously

  10. Ductile streaks in precision grinding of hard and brittle materials

    Indian Academy of Sciences (India)

    Author Affiliations. V C Venkatesh1 S Izman1 S Sharif1 T T Mon1 M Konneh1. Department of Manufacturing & Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, UTM Skudai, Malaysia ...

  11. Materials and Manufacturing Processing; Special Issue on Hard Carbon Films

    Science.gov (United States)

    1993-01-01

    Hiraki . Japanese Journal of Applied Physics, Vol.23, p.L234, (1984). 31. Davanloo, F., E.M. Jungerman, D.R. Jander, T.J. Lee, and C.B. Collins, Journal...Weissmantel, Physics Status Solodi A, Vel.71. p.K57, (1981). 84. Miyasato, T., Y. Kawakami. T. Kawano, and A. Hiraki , Japanese Journal of Applied...Kobayashi, Applied Physics Letters, Vol.51. No.10, p.737, (1987). 9. Suzuki, J., H. Kawarada, K. Mar, J. Wei, Y. Yokota, and A. Hiraki , Japanese

  12. Casimir stress in materials: Hard divergency at soft walls

    Science.gov (United States)

    Griniasty, Itay; Leonhardt, Ulf

    2017-11-01

    The Casimir force between macroscopic bodies is well understood, but not the Casimir stress inside bodies. Suppose empty space or a uniform medium meets a soft wall where the refractive index is continuous but its derivative jumps. For this situation we predict a characteristic power law for the stress inside the soft wall and close to its edges. Our result shows that such edges are not tolerated in the aggregation of liquids at surfaces, regardless whether the liquid is attracted or repelled.

  13. Ductile streaks in precision grinding of hard and brittle materials

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    The authors were able to obtain surfaces which satisfied ophthalmic conditions, but not those expected of precision optics. This technique was extended to ger- manium and silicon using both metal bonded and resinoid bonded wheels. The second technique involving plano surfaces was used on glass and silicon on a set- ...

  14. Advances in hard nucleus cataract surgery

    Directory of Open Access Journals (Sweden)

    Wei Cui

    2013-11-01

    Full Text Available Security and perfect vision and fewer complications are our goals in cataract surgery, and hard-nucleus cataract surgery is always a difficulty one. Many new studies indicate that micro-incision phacoemulsification in treating hard nucleus cataract is obviously effective. This article reviews the evolution process of hard nuclear cataract surgery, the new progress in the research of artificial intraocular lens for microincision, and analyse advantages and disadvantages of various surgical methods.

  15. Nanomechanics of hard films on compliant substrates.

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, Earl David, Jr. (Sandia National Laboratories, Albuquerque, NM); Emerson, John Allen (Sandia National Laboratories, Albuquerque, NM); Bahr, David F. (Washington State University, Pullman, WA); Moody, Neville Reid; Zhou, Xiao Wang; Hales, Lucas (University of Minnesota, Minneapolis, MN); Adams, David Price (Sandia National Laboratories, Albuquerque, NM); Yeager,John (Washington State University, Pullman, WA); Nyugen, Thao D. (Johns Hopkins University, Baltimore, MD); Corona, Edmundo (Sandia National Laboratories, Albuquerque, NM); Kennedy, Marian S. (Clemson University, Clemson, SC); Cordill, Megan J. (Erich Schmid Institute, Leoben, Austria)

    2009-09-01

    a result, our understanding of the critical relationship between adhesion, properties, and fracture for hard films on compliant substrates is limited. To address this issue, we integrated nanomechanical testing and mechanics-based modeling in a program to define the critical relationship between deformation and fracture of nanoscale films on compliant substrates. The approach involved designing model film systems and employing nano-scale experimental characterization techniques to isolate effects of compliance, viscoelasticity, and plasticity on deformation and fracture of thin hard films on substrates that spanned more than two orders of compliance magnitude exhibit different interface structures, have different adhesion strengths, and function differently under stress. The results of this work are described in six chapters. Chapter 1 provides the motivation for this work. Chapter 2 presents experimental results covering film system design, sample preparation, indentation response, and fracture including discussion on the effects of substrate compliance on fracture energies and buckle formation from existing models. Chapter 3 describes the use of analytical and finite element simulations to define the role of substrate compliance and film geometry on the indentation response of thin hard films on compliant substrates. Chapter 4 describes the development and application of cohesive zone model based finite element simulations to determine how substrate compliance affects debond growth. Chapter 5 describes the use of molecular dynamics simulations to define the effects of substrate compliance on interfacial fracture of thin hard tungsten films on silicon substrates. Chapter 6 describes the Workshops sponsored through this program to advance understanding of material and system behavior.

  16. Aespoe Hard Rock Laboratory Annual Report 1999

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-08-01

    Plug Test includes tests of backfill materials and emplacement methods and a test of a full-scale plug. The backfill and rock has been instrumented with about 230 transducers for measuring the thermo-hydro-mechanical processes.Saturation is in progress and is expected to take 1-2 years. The Long Term Tests of Buffer Material aim to validate models of buffer performance at standard KBS-3 repository conditions,and at quantifying clay buffer alteration processes at adverse conditions.The 4 long term test parcels and the additional 1-year parcel have been installed. Nine organisations from eight countries are currently participating in the Aespoe Hard Rock Laboratory in addition to SKB.

  17. Aespoe Hard Rock Laboratory. Annual report 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The surface and borehole investigations and the research work performed in parallel with construction have provided a thorough test of methods for investigation and evaluation of bedrock conditions for construction of a deep repository. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. The experimental results of the first tracer test with sorbing radioactive tracers have been obtained. These tests have been subject to blind predictions by the Aespoe Task Force on groundwater flow and transports of solutes. The manufacturing of the CHEMLAB probe was completed during 1996, and the first experiments were started early in 1997. During 1997 three experiments on diffusion in bentonite using {sup 57}Co, {sup 114}Cs,{sup 85}Sr, {sup 99}Tc, and {sup 131}I were conducted. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and instrumented. The characterization of the rock mass in the area of the prototype repository is in progress. The objectives of the Demonstration of Repository Technology are to develop, test, and demonstrate methodology and equipment for encapsulation and deposition of spent nuclear fuel. The demonstration of handling and deposition will be made in a new drift. The Backfill and Plug Test includes tests of backfill materials and emplacement methods and a test of a full scale plug. The backfill and rock will be instrumented with about 230 transducers for measuring the thermo-hydro-mechanical processes. The

  18. RutheniumII Complexes bearing Fused Polycyclic Ligands: From Fundamental Aspects to Potential Applications

    Directory of Open Access Journals (Sweden)

    Ludovic Troian-Gautier

    2014-04-01

    Full Text Available In this review, we first discuss the photophysics reported in the literature for mononuclear ruthenium complexes bearing ligands with extended aromaticity such as dipyrido[3,2-a:2',3'-c]phenazine (DPPZ, tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]-phenazine (TPPHZ,  tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]acridine (TPAC, 1,10-phenanthrolino[5,6-b]1,4,5,8,9,12-hexaazatriphenylene (PHEHAT 9,11,20,22-tetraaza- tetrapyrido[3,2-a:2',3'-c:3'',2''-l:2''',3'''-n]pentacene (TATPP, etc. Photophysical properties of binuclear and polynuclear complexes based on these extended ligands are then reported. We finally develop the use of binuclear complexes with extended π-systems for applications such as photocatalysis.

  19. Consequences of the electronic tuning of latent ruthenium-based olefin metathesis catalysts on their reactivity

    KAUST Repository

    Żukowska, Karolina

    2015-08-20

    Two ruthenium olefin metathesis initiators featuring electronically modified quinoline-based chelating carbene ligands are introduced. Their reactivity in RCM and ROMP reactions was tested and the results were compared to those obtained with the parent unsubstituted compound. The studied complexes are very stable at high temperatures up to 140 °C. The placement of an electron-withdrawing functionality translates into an enhanced activity in RCM. While electronically modified precatalysts, which exist predominantly in the trans-dichloro configuration, gave mostly the RCM and a minor amount of the cycloisomerization product, the unmodified congener, which preferentially exists as its cis-dichloro isomer, shows a switched reactivity. The position of the equilibrium between the cis- and the trans-dichloro species was found to be the crucial factor governing the reactivity of the complexes.

  20. Dehydrogenation of Formic Acid Catalyzed by a Ruthenium Complex with an N,N′-Diimine Ligand

    KAUST Repository

    Guan, Chao

    2016-12-17

    We report a ruthenium complex containing an N,N′-diimine ligand for the selective decomposition of formic acid to H and CO in water in the absence of any organic additives. A turnover frequency of 12000 h and a turnover number of 350 000 at 90 °C were achieved in the HCOOH/HCOONa aqueous solution. Efficient production of high-pressure H and CO (24.0 MPa (3480 psi)) was achieved through the decomposition of formic acid with no formation of CO. Mechanistic studies by NMR and DFT calculations indicate that there may be two competitive pathways for the key hydride transfer rate-determining step in the catalytic process.