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Sample records for samarium borides

  1. Analysis of aluminum boride and zirconium boride

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Yasuo (Institute of Physical and Chemical Research, Wako, Saitama (Japan))

    1982-09-01

    A method for analyzing aluminum and zirconium borides is presented. Decomposition of the borides was achieved in a Uniseal Decomposition Vessel (capacity, 23 ml), in which aluminum boride was heated with (1 + 1) HNO/sub 3/ at 150/sup 0/C for 3 h and zirconium boride with a mixture of (1 + 1) HNO/sub 3/ and (1 + 5) H/sub 2/SO/sub 4/ at the same temperature for 6 h. Aluminum and boron in the solution obtained were separated with cation exchange resin (Dowex 50 WX 8). Boron in the effluent was determined with the titrimetric method using mannite. Aluminum adsorped on the resin was eluted with 2 M HCl and determined by chelatometric titration. Zirconium was separated from boron as zirconium hydroxide by precipitation with NaOH and by filtration with a Nucleopore membrane filter. Boron in the filtrate was determined by the above mentioned method. After dissolution of zirconium hydroxide with HCl, zirconium was precipitated with mandelic acid. The optimum concentration of HCl for the complete precipitation of zirconium mandelate was (2 -- 3) M. The precipitate was filtered on a G 4 glass filter, dried at 110/sup 0/C and weighted as zirconium tetramandelate. The following boride samples were analyzed: Selected crystals of ..cap alpha..-AlB/sub 12/ and ..beta..-AlB/sub 12/, and two ZrB/sub 2/ samples, the one prepared by carbothermic reduction and the other by direct reaction of zirconium and boron.

  2. Kinetics of borided gear steels

    Indian Academy of Sciences (India)

    The boride layer was characterized by optical microscopy, X-ray diffraction technique and microVickers hardness tester. X-ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FeB, Fe2B, CrB and Cr2B compounds. The thickness of the boride layer increases by increasing boriding ...

  3. Kinetics of borided gear steels

    Indian Academy of Sciences (India)

    source used, boriding temperature, treatment time, and properties of the borided material (Sahin. & Meric 2002 ... The boriding heat treatment was carried out in solid medium containing an Ekabor-II ..... 2007 Growth kinetics of boride layers on iron-chromium alloys and their dry abrasive wear resistance,. Materials Science ...

  4. An investigation on borided AISI 1020 steel

    Science.gov (United States)

    Altinsoy, I.; Efe, F. G. Celebi; Ipek, M.; Ozbek, I.; Zeytin, S.; Bindal, C.

    2013-12-01

    In this study, we investigated some properties of borided AISI 1020 steel. Boronizing heat treatment was carried out at 800°C, 875°C and 950°C for 2, 4, 6 and 8 h using Ekabor 1 powders. The hardness of borides formed on the steel substrate measured via Vickers indenter was about 1500 HVN. The thickness of boride layers depending on the process temperature and time was ranged from 20.5 to 216 μm. The presence of Fe2B boride was determined by XRD analysis. SEM microscope studies showed that the borides formed on the AISI 1020 steel have columnar nature. Kinetics studies reveal a parabolic relationship between layer depth and process time, and the activation energy is calculated as 164,356 kJ/mol. Moreover, an attempt was made to investigate the possibility of predicting the iso-thickness of boride layer and to establish an empirical relationship between process parameters of boriding and boride layer for industrial applications.

  5. Characterization of AISI 4140 borided steels

    Energy Technology Data Exchange (ETDEWEB)

    Campos-Silva, I., E-mail: icampos@ipn.mx [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico); Ortiz-Dominguez, M.; Lopez-Perrusquia, N.; Meneses-Amador, A. [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico); Escobar-Galindo, R. [Instituto de Ciencia de Materiales de Madrid (CSIC), E-28049 Cantoblanco, Madrid (Spain); Martinez-Trinidad, J. [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico)

    2010-02-01

    The present study characterizes the surface of AISI 4140 steels exposed to the paste-boriding process. The formation of Fe{sub 2}B hard coatings was obtained in the temperature range 1123-1273 K with different exposure times, using a 4 mm thick layer of boron carbide paste over the material surface. First, the growth kinetics of boride layers at the surface of AISI 4140 steels was evaluated. Second, the presence and distribution of alloying elements on the Fe{sub 2}B phase was measured using the Glow Discharge Optical Emission Spectrometry (GDOES) technique. Further, thermal residual stresses produced on the borided phase were evaluated by X-ray diffraction (XRD) analysis. The fracture toughness of the iron boride layer of the AISI 4140 borided steels was estimated using a Vickers microindentation induced-fracture testing at a constant distance of 25 {mu}m from the surface. The force criterion of fracture toughness was determined from the extent of brittle cracks, both parallel and perpendicular to the surface, originating at the tips of an indenter impression. The fracture toughness values obtained by the Palmqvist crack model are expressed in the form K{sub C}({pi}/2) > K{sub C} > K{sub C}(0) for the different applied loads and experimental parameters of the boriding process.

  6. Synthesis of Samarium Cobalt Nanoblades

    Energy Technology Data Exchange (ETDEWEB)

    Darren M. Steele

    2010-08-25

    As new portable particle acceleration technologies become feasible the need for small high performance permanent magnets becomes critical. With particle accelerating cavities of a few microns, the photonic crystal fiber (PCF) candidate demands magnets of comparable size. To address this need, samarium cobalt (SmCo) nanoblades were attempted to be synthesized using the polyol process. Since it is preferable to have blades of 1-2 {micro}m in length, key parameters affecting size and morphology including method of stirring, reaction temperature, reaction time and addition of hydroxide were examined. Nanoparticles consisting of 70-200 nm spherical clusters with a 3-5 nm polyvinylpyrrolidone (PVP) coating were synthesized at 285 C and found to be ferromagnetic. Nanoblades of 25nm in length were observed at the surface of the nanoclusters and appeared to suggest agglomeration was occurring even with PVP employed. Morphology and size were characterized using a transmission electron microscope (TEM). Powder X-Ray Diffraction (XRD) analysis was conducted to determine composition but no supportive evidence for any particular SmCo phase has yet been observed.

  7. The electrochemical synthesis of europium boride

    Directory of Open Access Journals (Sweden)

    Bukatova G.A.

    2003-01-01

    Full Text Available The electroreduction of boron, europium and the electrochemical synthesis of europium boride have been investigated in NaCl-KCl-NaF(10 wt. % melt on silver and molybdenum electrodes. The parameters of boron reduction in the chloride-fluoride melt have been obtained and the character of its joint deposition with europium has been studied.

  8. The electrochemical synthesis of europium boride

    OpenAIRE

    Bukatova G.A.; Kuznetsov S.A.; Gaune-Escard M.

    2003-01-01

    The electroreduction of boron, europium and the electrochemical synthesis of europium boride have been investigated in NaCl-KCl-NaF(10 wt. %) melt on silver and molybdenum electrodes. The parameters of boron reduction in the chloride-fluoride melt have been obtained and the character of its joint deposition with europium has been studied.

  9. Characterization of rough interfaces obtained by boriding

    Energy Technology Data Exchange (ETDEWEB)

    Campos-Silva, I. [Instituto Politecnico Nacional, SEPI-ESIME, U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F. 07738 (Mexico)], E-mail: icampos@ipn.mx; Balankin, A.S. [Instituto Politecnico Nacional, SEPI-ESIME, U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F. 07738 (Mexico); Sierra, A.H. [Instituto Politecnico Nacional, UPIICSA, Av. Te 950, Col Granjas, Mexico D.F. 08400 (Mexico); Lopez-Perrusquia, N. [Instituto Politecnico Nacional, SEPI-ESIME, U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F. 07738 (Mexico); Escobar-Galindo, R. [Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, Madrid E-28049 (Spain); Morales-Matamoros, D. [Instituto Mexicano del Petroleo, Eje Lazaro Cardenas Norte, Mexico D.F. 07738 (Mexico)

    2008-12-30

    This study evaluates the morphology of borided interfaces by means of the fractal theory. The boride layers were formed in the AISI M2 steel by applying the paste boriding treatment at temperatures of 1253 and 1273 K and treatment times of 2 and 6 h, while a boron carbide paste thickness of 4 or 5 mm covered the samples surface in order to produce the boron diffusion. The morphology of interfaces formed between FeB and Fe{sub 2}B layers and between Fe{sub 2}B layer and steel substrate was analyzed by the rescaled-range (R/S), root-mean-square (RMS), and Fourier power spectrum (FPS) methods. Moreover, the multi-affine spectra of roughness exponent were obtained by calculating the q-order height-height correlation functions. We found that both interfaces are multi-affine, rather than self-affine. The multi-affine spectra of roughness exponents are found to be different for FeB/Fe{sub 2}B and Fe{sub 2}B/substrate interfaces, but independent on the treatment parameters (boron carbide paste thickness, temperature, and boriding time). Furthermore, we found that the multi-affine spectra of both interfaces behave as it is expected for 'universal multi-fractals' with the Levy index {gamma} = 1, associated with the multiplicative cascades with a log-Cauchy distribution. Furthermore, our data suggest a great homogeneity of the boron diffusion field, characterized by universal fractal dimension D{sub diff} = 2.90 {+-} 0.01. These findings provide a novel insight into the nature of phase formation during the boriding treatment.

  10. Boriding of binary Ni-Ti shape memory alloys

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    Ucar, Nazim; Dogan, Sule [Suleyman Demirel Univ., Isparta (Turkey). Physics Dept.; Karakas, Mustafa Serdar [Cankaya Univ., Ankara (Turkey). Materials Science and Engineering Dept.; Calik, Adnan [Suleyman Demirel Univ., Isparta (Turkey). Manufacturing Engineering Dept.

    2016-07-01

    Boriding of binary Ni-Ti shape memory alloys was carried out in a solid medium at 1273 K for 2, 4, 6, and 8 h using the powder pack method with proprietary Ekabor-Ni powders. Characterization of the boride layer formed on the surface of alloys was done by optical microscopy and scanning electron microscopy. The presence of boride, silicide, and borosilicide phases in the boride layers was confirmed by X-ray diffraction analysis. The thickness and microhardness of the boride layers increased with increasing boriding time. Hardness profiles showed a rapid decrease in hardness moving from the boride layer to the main structure. The high hardness of the boride layer was attributed mainly to the formation of TiB{sub 2}. A parabolic relationship was observed between layer thickness and boriding time, and the growth rate constant for the boriding treatment was calculated as 0.62 x 10{sup -8} cm{sup 2}s{sup -1}.

  11. Fracture Microindentation on boride layers on AISI 1020 steel

    Science.gov (United States)

    Prince, M.; Thanu, A. Justin; Arjun, S. L.; Velmurugan, U.; Gopalakrishnan, P.

    2016-02-01

    In this paper, an attempt has been made to enhance the fracture toughness (Kc) of boride layer using multi-component (Ni, Cr and B) laser bonding. The fracture toughness of continuously pack borided, interrupted pack borided and multi-component (Ni, Cr and B) laser borided steel specimens was measured using Vickers microindentation fracture toughness test as per ASTM E384 standard. The fracture toughness of continuously pack borided layer was - 3.3 MPa.m1/2. The fracture toughness of interrupted boride layer was in the range of - 4.9 MPa.m1/2. The fracture toughness of multi-component (Ni, Cr and B) laser borided layer was in the range of 13.8 - 18.3 MPa.m1/2. A significant improvement in fracture toughness of laser treated specimens was observed from the experimental results. This may be due to better distribution of boron, nickel, chromium and other alloying elements due to laser treatment and relatively more uniform boride layer as compared with continuously pack borided layer and interrupted pack borided layer.

  12. Investigation of the diffusion kinetics of borided stainless steels

    Science.gov (United States)

    Kayali, Yusuf

    2013-12-01

    In this study, the kinetics of borides formed on AISI 420, AISI 304 and AISI 304L stainless steels was investigated. Boronizing treatment was carried out using Ekabor-II powders at the processing temperatures of 1123, 1173 and 1223 K for 2, 4 and 6 h. The phases of the boride layers of borided AISI 420, AISI 304 and AISI 304L stainless steels were FeB, Fe2B, CrB and NiB, respectively. The thickness of the boride layer formed on the borided steels ranged from 4.6 to 64 μm depending on the boriding temperature, boriding time and alloying elements of the stainless steels. Depending on the chemical composition, temperature and layer thickness, the activation energies of boron in AISI 420, AISI 304 and AISI 304L stainless steels were found to be 206.161, 234.641 and 222.818 kJ/mol, respectively. The kinetics of growth of the boride layers formed on the AISI 420, AISI 304 and AISI 304L stainless steels and the thickness of the boride layers were investigated.

  13. Preparation of single phase molybdenum boride

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    Camurlu, Hasan Erdem, E-mail: erdemcamurlu@gmail.com [Akdeniz University, Mechanical Engineering Department, 07058, Antalya (Turkey)

    2011-04-28

    Highlights: > Formation of Mo and a mixture of molybdenum boride phases take place in preparation of molybdenum borides. > It is intricate to prepare single phase molybdenum borides. > Formation of single phase MoB from MoO{sub 3} + B{sub 2}O{sub 3} + Mg mixtures has not been reported previously. > Single phase MoB was successfully prepared through a combination of mechanochemical synthesis and annealing process. - Abstract: The formation of MoB through volume combustion synthesis (VCS), and through mechanochemical synthesis (MCS) followed by annealing has been investigated. MoO{sub 3}, B{sub 2}O{sub 3} and Mg were used as reactants while MgO and NaCl were introduced as diluents. Products were leached in dilute HCl solution and were subjected to X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) examinations. Mo was the major phase component in the VCS products under all the experimental conditions. Mo{sub 2}B, MoB, MoB{sub 2} and Mo{sub 2}B{sub 5} were found as minor phases. Products of MCS contained a mixture of Mo{sub 2}B, MoB, MoB{sub 2} and Mo. After annealing the MCS product at 1400 deg. C for 3 h, single phase {alpha}-MoB was obtained.

  14. Growth kinetics of boride coatings formed at the surface AISI M2 during dehydrated paste pack boriding

    Energy Technology Data Exchange (ETDEWEB)

    Doñu Ruiz, M.A., E-mail: mdonur0800@alumno.ipn.mx [Universidad Politécnica del Valle de México UPVM, Grupo Ciencia e Ingeniería de Materiales, Av. Mexiquense S/N Esquina Av. Universidad Politécnica, Col Villa Esmeralda, 54910 Tultitlan (Mexico); López Perrusquia, N.; Sánchez Huerta, D. [Universidad Politécnica del Valle de México UPVM, Grupo Ciencia e Ingeniería de Materiales, Av. Mexiquense S/N Esquina Av. Universidad Politécnica, Col Villa Esmeralda, 54910 Tultitlan (Mexico); Torres San Miguel, C.R.; Urriolagoitia Calderón, G.M. [Instituto Politécnico Nacional, SEPI-ESIME, Unidad Profesional Adolfo López Mateos Zacatenco, Edificio 5, 2do. Piso, Col. Lindavista, CP 07738 México, D.F. (Mexico); Cerillo Moreno, E.A. [Universidad Politécnica del Valle de México UPVM, Grupo Ciencia e Ingeniería de Materiales, Av. Mexiquense S/N Esquina Av. Universidad Politécnica, Col Villa Esmeralda, 54910 Tultitlan (Mexico); Cortes Suarez, J.V. [Univerisdad Autónoma Metropolitana Unidad Azcapotzalco, Av. San Pablo 180 Azcapotzalco 02200, Área de Ciencia de los Materiales, México, D.F. (Mexico)

    2015-12-01

    The growth kinetics of the boride coatings (FeB and Fe{sub 2}B) at the surface of AISI M2 high speed steels were studied in this work. Boriding thermochemical treatment was carried out by dehydrated paste pack at three different temperatures 1173, 1223, and 1273 K and four exposure times 1, 3, 5, and 7 h, respectively. The presence of FeB and Fe{sub 2}B phases was identified by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction method. In order to obtain the boron diffusion coefficients at the FeB/Fe{sub 2}B boride coatings, a mathematical model based on the mass balance at the growing interfaces was proposed under certain assumptions. Likewise the parabolic growth constants and the boride incubation time were established as a function of the parameters η (T) and ε (T). The activation energy values estimated for the FeB and Fe{sub 2}B layers were 233.42 and 211.89 kJ mol{sup −1} respectively. A good agreement was obtained between the simulated values of boride layer thicknesses and the experimental results. Finally, empirical relationships of boride coating thickness as a function of boriding temperature and time are presented. - Highlights: • Formed boride coatings at the surface of AISI M2 high speed steels by new process dehydrated paste pack boriding. • The model was based on the mass balance equation at the FeB/Fe{sub 2}B and Fe{sub 2}B/Fe interfaces by considering the boride incubation time. • A good agreement was obtained between the simulated values of boride layers coatings and the experimental results.

  15. Carbide and boride laser modification of steels

    Science.gov (United States)

    Major, Boguslaw; Ebner, Reinhold

    1997-10-01

    Microstructure modification by laser remelting or laser alloying was studied on carbon Ck45 and high speed steels. Laser remelting of Ck45 by overlapping laser tracks led to a great refinement of martensitic structure, especially in the heat affected zone of subsequent laser track. High speed steel (HSS) M2 after laser remelting showed, beside the tetragonal martensite, the diffraction lines of cubic carbides of the M6C and M12C types. Laser alloying of M2 HSS using vanadium carbide (VC) additions caused increasing of eutectic in the interdendritic space, which was accompanied with reduction of the M6C and rising of the MC. M2 HSS laser alloyed with molybdenum carbide (Mo2C) showed formation of the M6C for the hipereutectic compositions while at the highest concentrations of molybdenum, primary dendrites of the M2C and stabilized ferrite were stated. High additions of borides: CrB or VB2; developed formation of the primary borides of blocky type containing a high amount of W, Cr or W, V, respectively. Laser alloying of Ck45 by means of: CrB, VB2 and B4C showed: in the case of CrB an eutectic (alpha) '/M3(C,B)/M2B as well as primary precipitates of the M2B phase for hipereutectic compositions; by adding VB2, the M3B2 and M2B phases were identified experimentally for hipereutectic concentrations; for alloying using B4C, the cellular dendritic structure together with primary borides of the (tau) -M23(C,B)6 phase were stated for hipereutectic compositions. The phase diagrams of M2 HSS + (VC or Mo2C) as well as Ck45 + B4C systems were calculated to predict changes of the constitutions due to laser alloying. Comparison of the solidification structures established experimentally with the calculated phase diagrams revealed a good correlation for the carbides, especially.

  16. Effect of boron paste thickness on the growth kinetics of polyphase boride coatings during the boriding process

    Energy Technology Data Exchange (ETDEWEB)

    Campos, I. [Tecnologico de Monterrey, Campus Ciudad de Mexico, Mechanical Department, Calle del Puente 222 Col., Ejidos de Huipulco, Mexico, DF 14380 (Mexico)]. E-mail: ivan.campos@itesm.mx; Torres, R. [Tecnologico de Monterrey, Campus Ciudad de Mexico, Mechanical Department, Calle del Puente 222 Col., Ejidos de Huipulco, Mexico, DF 14380 (Mexico); Bautista, O. [Tecnologico de Monterrey, Campus Ciudad de Mexico, Mechanical Department, Calle del Puente 222 Col., Ejidos de Huipulco, Mexico, DF 14380 (Mexico); Ramirez, G. [IPN-SEPI-ESIME, U.P. Adolfo Lopez Mateos, Zacatenco, Mexico, DF 07738 (Mexico); Zuniga, L. [Tecnologico de Monterrey, Campus Ciudad de Mexico, Mechanical Department, Calle del Puente 222 Col., Ejidos de Huipulco, Mexico, DF 14380 (Mexico)

    2006-01-15

    The growth kinetics of FeB and Fe{sub 2}B phases forming on AISI M2 steel by paste boriding was studied using different values of paste thickness, treating temperature and exposure time. The growth of iron boride layers is described by the mass balance equation between phases in thermodynamic equilibrium, assuming that the boron concentration at the interfaces remain constant during the treatment. The experimental results show that boron mobility and growth kinetics of iron borides are considerably increased when the paste thickness is increased at constant values of temperature and exposure time.

  17. Particle-Size-Induced Valence Changes in Samarium Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Mason, M. G.; Lee, S. -T.; Apai, G.; Davis, R. F.; Shirley, D. A.; Franciosi, A.; Weaver, J. H.

    1981-09-01

    Samarium clusters exhibit mixed-valence behavior which is sensitive to particle size. XPS and UPS data show samarium to be primarily divalent (4f{sup 6} ) at small particle size. The trivalent state (4f{sup 5} ) becomes progressively more abundant with increasing s1ze, becoming the dominant state for the bulk metal. These results are interpreted using a model in which band narrowing, due to reduced surface coordination, is more dominant than surface tension effects in establishing the valence of small samarium clusters.

  18. Investigation of diffusion kinetics of plasma paste borided AISI 8620 ...

    Indian Academy of Sciences (India)

    Abstract. In the present study, AISI 8620 steel was plasma paste borided by using various B2O3 paste mixture. The plasma paste boriding process was carried out in a dc plasma system at temperatures of 973, 1023 and 1073 K for 2, 5 and 7 h in a gas mixture of 70% H2 -30% Ar under a constant pressure of 10 mbar.

  19. Investigation of diffusion kinetics of plasma paste borided AISI 8620 ...

    Indian Academy of Sciences (India)

    ... diffraction, Vickers micro-hardness tester and the growth kinetics of the boride layers. X-ray diffraction analysis of boride layers on the surface of the steel revealed FeB and Fe2B phases. Depending on temperature and layer thickness, the activation energies of boron in steel were found to be 124.7 kJ/mol for 100% B2O3.

  20. Binary and Ternary Explorations of the Molybdenum Boride System

    OpenAIRE

    Dismukes, Avalon Hope

    2015-01-01

    Refractory metal borides have recently generated intense interest in materials chemistry. These compounds have been shown to possess many advantageous properties, such as exceptionally high hardness, electrical conductivity, and even superconductivity. Higher molybdenum borides are discussed as compounds of interest in this category of materials. However, the complex phase relationships in the molybdenum-boron system complicate the preparation of phase-pure samples. MoB2 and Mo2B4 have both b...

  1. Yellow-green electroluminescence of samarium complexes of 8-hydroxyquinoline

    Energy Technology Data Exchange (ETDEWEB)

    Behzad, Sara Karimi; Najafi, Ezzatollah [Department of Chemistry Shahid Beheshti University G.C., Tehran 1983963113 (Iran, Islamic Republic of); Amini, Mostafa M., E-mail: m-pouramini@sbu.ac.ir [Department of Chemistry Shahid Beheshti University G.C., Tehran 1983963113 (Iran, Islamic Republic of); Janghouri, Mohammad; Mohajerani, Ezeddin [Laser Research Institute Shahid Beheshti University G.C., Tehran 1983963113 (Iran, Islamic Republic of); Ng, Seik Weng [Department of Chemistry, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-12-15

    Four novel samarium complexes were prepared by reacting samarium(III) nitrate with 8-hydroxyquinoline, 2-methyl-8-hydroxyquinoline, and 1,10-phenanthroline and utilized as emitting materials in the electroluminescence device. All complexes were characterized by elemental analysis, infrared, UV–vis and {sup 1}H NMR spectroscopes and the molecular structure of a representative complex, [Sm{sub 2}(Me-HQ){sub 4}(NO{sub 3}){sub 6}] (1), was determined by single-crystal X-ray diffraction. Utilization of a π-conjugated (phenanthroline) ligand as a second ligand in the structure of the samarium complexes resulted in red shifts in both absorption and fluorescence spectra of complexes and moderately enhanced the photoluminescence intensity and the fluorescence quantum yield. The maximum emission peaks showed that a good correlation exists between the nature of the substituent group on the 8-hydroxyquinoline and the addition of the π-conjugated ligand in the structure of samarium complexes and emission wavelength. Devices with samarium(III) complexes with structure of ITO/PEDOT:PSS (90 nm)/PVK:PBD:Sm(III) complexes (75 nm)/Al (180 nm) were fabricated. In the electroluminescence (EL) spectra of the devices, a strong ligand-centered emission and narrow bands arising from the {sup 4}G{sub 5/2}→{sup 6}H{sub J} transitions (J=7/2, 9/2, and 11/2) of the samarium ion were observed for the complexes. The electroluminescent spectra of the samarium complexes were red-shifted as compared with the PVK:PBD blend. We believe that the electroluminescence performance of OLED devices based on samarium complexes relies on overlaps between the absorption of the samarium compounds and the emission of PVK:PBD. This revealed that it is possible to evaluate the electroluminescence performance of the samarium compounds-doped OLED devices based on the emission of PVK:PBD and the absorption of the dopants. - Highlights: • Four novel photoluminescence samarium complexes have been synthesized.

  2. PECULIARITIES OF BORIDE COATING FORMATION MADE OF COMPOSITE METAL-THERMAL POWDER MEDIA

    Directory of Open Access Journals (Sweden)

    N. A. Galynskaya

    2011-01-01

    Full Text Available The paper has investigated an influence of compositions pertaining to complex powder metal-thermal saturating media for boriding on phase-, structure formation and properties of boride coatings in respect of carbon steel.

  3. Characterisation of Wear Resistant Boride Layers on a Tool Steel by Activity Controlled Pack Boronising

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2015-01-01

    The present work addresses the production and characterisation of iron boride layers by pack boronising of a Vanadis 6 tool steel. The boride layers were produced at 900°C for 2h using different pack compositions in order to obtain a single-phase boride layer. The layers were characterized by ele...

  4. Biodistribution of samarium-153-EDTMP in rats treated with docetaxel

    Energy Technology Data Exchange (ETDEWEB)

    Villarim Neto, Arthur; Acucena, Maria Kadja Meneses Torres; Pereira, Kercia Regina Santos Gomes; Rego, Amalia Cinthia Meneses [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Postgraduate Program in Health Sciences; Azevedo, Italo Medeiros; Medeiros, Aldo Cunha [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. of Surgery; Bernardo-Filho, Mario [State University of Rio de Janeiro, RJ (Brazil). Dept. of Biophysics and Biometry

    2009-01-15

    Purpose: Many patients with metastatic bone disease have to use radiopharmaceuticals associated with chemotherapy to relieve bone pain. The aim of this study was to assess the influence of docetaxel on the biodistribution of samarium-153-EDTMP in bones and other organs of rats. Methods: Wistar male rats were randomly allocated into 2 groups of 6 rats each. The DS (docetaxel/samarium) group received docetaxel (15 mg/kg) intraperitoneally in two cycles 11 days apart. The S (samarium/control) group rats were not treated with docetaxel. Nine days after chemotherapy, all the rats were injected with 0.1 ml of samarium-153-EDTMP via orbital plexus (25 {mu} Ci. After 2 hours, the animals were killed and samples of the brain, thyroid, lung, heart, stomach, colon, liver, kidney and both femurs were removed. The percentage radioactivity of each sample (% ATI / g) was determined in an automatic gamma-counter (Wizard-1470, Perkin-Elmer, Finland). Results: On the ninth day after the administration of the second chemotherapy cycle, the rats had a significant weight loss (314.50 +- 22.09 g) compared (p<0.5) to pre-treatment weight (353.66 {+-} 22.8). The % ATI/g in the samples of rats treated with samarium-153-EDTMP had a significant reduction in the right femur, left femur, kidney, liver and lungs of animals treated with docetaxel, compared to the control rats. Conclusion: The combination of docetaxel and samarium-153-EDTMP was associated with a lower response rate in the biodistribution of the radiopharmaceutical to targeted tissues. Further investigation into the impact of docetaxel on biodistribution of samarium-153-EDTMP would complement the findings of this study. (author)

  5. The characterization of boride layer on the St37 iron

    Science.gov (United States)

    Sutrisno, Soegijono, Bambang

    2012-06-01

    The property such as microhardness of boride layer formed on St37 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 1000°C 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 St37 was over 2000 HV, while the hardness of untreated St37 iron was about 123,82 HV. Depending on process time and temperature, the depth of boride layer ranges from 20 to 60 μm, leading to a diffusion controlled process.

  6. Corrosion behavior of boride layers evaluated by the EIS technique

    Energy Technology Data Exchange (ETDEWEB)

    Campos, I. [Instituto Politecnico Nacional. SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F. 07738 (Mexico)], E-mail: icampos@ipn.mx; Palomar-Pardave, M. [Universidad Autonoma Metropolitana-Azcapotzalco, Materials Department, Avenue San Pablo 180 Col. Reynosa Tamaulipas, Mexico D.F. 02200 (Mexico); Amador, A. [Tecnologico de Monterrey, Campus Ciudad de Mexico, Calle del Puente 222 Col. Ejidos de Huipulco, Mexico D.F. 14380 (Mexico); VillaVelazquez, C. [Instituto Politecnico Nacional. SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F. 07738 (Mexico); Hadad, J. [Tecnologico de Monterrey, Campus Ciudad de Mexico, Calle del Puente 222 Col. Ejidos de Huipulco, Mexico D.F. 14380 (Mexico)

    2007-09-30

    The corrosion behavior of boride layers at the AISI 304 steel surface is evaluated in the present study. Electrochemical impedance spectroscopy (EIS) technique was used for the evaluation of the polarization resistance at the steel surface, with the aid of AUTOLAB potentiostat. Samples were treated with boron paste thickness of 4 and 5 mm, in the range of temperatures 1123 {<=} T {<=} 1273 K and exposed time of 4 and 6 h. The electrochemical technique employed 10 mV AC with a frequency scan range from 8 kHz to 3 mHz in deaerated 0.1 M NaCl solution. Nyquist diagrams show that the highest values of corrosion resistance are present in the samples borided at the temperature of 1273 K, with treatment time of 4 h and 4 mm of boron paste thickness. The values of corrosion resistance on borided steels are compared with the porosity exhibited in the layers.

  7. Laser borided composite layer produced on austenitic 316L steel

    Directory of Open Access Journals (Sweden)

    Mikołajczak Daria

    2016-12-01

    Full Text Available Abstract Austenitic 316L steel is well-known for its good resistance to corrosion and oxidation. Therefore, this material is often used wherever corrosive media or high temperatures are to be expected. The main drawback of this material is very low hardness and low resistance to mechanical wear. In this study, the laser boriding was used in order to improve the wear behavior of this material. As a consequence, a composite surface layer was produced. The microstructure of laser-borided steel was characterized by only two zones: re-melted zone and base material. In the re-melted zone, a composite microstructure, consisting of hard ceramic phases (borides and a soft austenitic matrix, was observed. A significant increase in hardness and wear resistance of such a layer was obtained.

  8. The Basis for Developing Samarium AMS for Fuel Cycle Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B A; Biegalski, S R; Whitney, S M; Tumey, S J; Weaver, C J

    2008-10-13

    Modeling of nuclear reactor fuel burnup indicates that the production of samarium isotopes can vary significantly with reactor type and fuel cycle. The isotopic concentrations of {sup 146}Sm, {sup 149}Sm, and {sup 151}Sm are potential signatures of fuel reprocessing, if analytical techniques can overcome the inherent challenges of lanthanide chemistry, isobaric interferences, and mass/charge interferences. We review the current limitations in measurement of the target samarium isotopes and describe potential approaches for developing Sm-AMS. AMS sample form and preparation chemistry will be discussed as well as possible spectrometer operating conditions.

  9. Pulsed nanocrystalline plasma electrolytic boriding as a novel ...

    Indian Academy of Sciences (India)

    WINTEC

    of the porous complex titanium borided layer. Large val- ues of polarization resistance (Rp) are also noted in all the samples. A high Rp value is an indication of the working electrode strongly resisting change from its equilibrium state and corresponds to a low rate of titanium ion re- lease. This behaviour is clearly noted and ...

  10. Pulsed nanocrystalline plasma electrolytic boriding as a novel ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 30; Issue 6. Pulsed nanocrystalline plasma electrolytic boriding as a novel method for corrosion protection of CP-Ti (Part 1: Different frequency and duty cycle). M Kh Aliev A Saboor. Alloys and Steels Volume 30 Issue 6 December 2007 pp 601-605 ...

  11. Equilibrium And Growth Morphologies Of Trinickel Boride Ni3b ...

    African Journals Online (AJOL)

    The morphology of the trinickel boride Ni3B precipitates during slow cooling in differential thermal analysis (DTA) has been investigated using high resolution electron microscopy (HREM). Due to the large development of the facets of the type {022}, the crystal tends towards an equilibrium morphology whereas the growth ...

  12. Optical characteristics of transparent samarium oxide thin films ...

    Indian Academy of Sciences (India)

    Optical characteristics of transparent samarium oxide thin films deposited by the radio-frequency sputtering technique. A A ATTA M M EL-NAHASS KHALED M ELSABAWY M M ABD EL-RAHEEM A M HASSANIEN A ALHUTHALI ALI BADAWI AMAR MERAZGA. Regular Volume 87 Issue 5 November 2016 Article ID 72 ...

  13. Optical properties of zinc–vanadium glasses doped with samarium ...

    Indian Academy of Sciences (India)

    Zinc–vanadium glasses doped with samarium oxide having the chemical composition Sm2O3() ZnO(40-)V2O5(60) (where = 0.1–0.5 mol%) were prepared by melt quenching method. The density of these glasses was measured by Archimedes method; the corresponding molar volumes have also been calculated.

  14. Optical properties of samarium doped zinc–tellurite glasses

    Indian Academy of Sciences (India)

    Unknown

    Optical properties of samarium doped zinc–tellurite glasses. B ERAIAH. Department of Physics, Karnatak University, Dharwad 580 003, India. Present address: Department of Physics, Bangalore University, Bangalore 560 056, India. MS received 20 March 2006; revised 13 June 2006. Abstract. Glasses with the composition, ...

  15. Effect of second ligand on the luminescence of Samarium (III ...

    Indian Academy of Sciences (India)

    Effect of second ligand on the luminescence of Samarium (III) dibenzoylmethane complexes: Syntheses, crystal structures, thermal analysis and luminescence study. MUHAMMAD IDIRIS SALEH, MIN YEE CHOO, TAI WEI CHAN and MOHD R RAZALI. ∗. School of Chemical Sciences, Universiti Sains Malaysia, Penang, ...

  16. Effect of second ligand on the luminescence of Samarium (III ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 12. Effect of second ligand on the luminescence of Samarium (III) dibenzoylmethane complexes: ... Muhammad Idiris Saleh1 Min Yee Choo1 Tai Wei Chan1 Mohd R Razali1. School of Chemical Sciences, Universiti Sains Malaysia, Penang, Malaysia ...

  17. Growth kinetics of boride layers formed on 99.0% purity nickel

    Indian Academy of Sciences (India)

    The boride layer was characterized by optical microscopy, X-ray diffraction technique and micro-Vickers hardness tester. X-ray diffraction analysis revealed the existence of NiB, Ni2B, Ni3B and Ni4B3 compounds at the surface of borided Nickel 201 alloy. The thickness of the boride layer increased with an increase in the ...

  18. Hard Surface Layers by Pack Boriding and Gaseous Thermo-Reactive Deposition and Diffusion Treatments

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Bottoli, Federico; Dahl, Kristian Vinter

    2017-01-01

    Thermo-reactive deposition and diffusion (TRD) and boriding are thermochemical processes that result in very high surface hardness by conversion of the surface into carbides/nitrides and borides, respectively. These treatments offer significant advantages in terms of hardness, adhesion, tribo......-based borides. The obtained surface layers were characterized with X-ray diffraction, scanning electron microscopy, reflected light microscopy, and micro-indentation....

  19. Fracture Toughness of Thick Boride Layers Estimated by the Cross-Sectioned Scratch Test

    Science.gov (United States)

    Campos-Silva, I.; Flores-Jiménez, M.; Bravo-Bárcenas, D.; Rodríguez-Castro, G.; Martínez-Trinidad, J.; Meneses-Amador, A.

    2018-01-01

    New results about the fracture toughness (K c) of thick boride layers estimated by the cross-sectioned scratch test are presented in this study. The FeB-Fe2B layers developed at the surface of borided AISI 1018 and AISI 1045 steels and the Fe2B layer formed on the borided AISI 1045 steel exposed to a diffusion annealing process (DAP) were used for this purpose. The cross-sectioned scratch tests were performed with a Vickers diamond stylus drawn across the thick boride layer under a constant load to produce a half-cone-shaped fracture near to the top surface of the borided steels. The height of the half-cone-shaped fracture as a function of the cross-sectioned scratch loads was used to determine the fracture toughness of the FeB and Fe2B layers. The results showed a fracture resistance of ˜2.8 {MPa}√ m for the FeB layer formed at the surface of borided AISI 1045 steel. Likewise, the effect of the DAP on the surface of the borided AISI 1045 steel promoted the formation of an exclusively Fe2B layer, with an increase in the fracture toughness of the whole boride layer around 5 {MPa}√ m . Finally, the principle of the technique can be used to minimize the influence of the anisotropic properties on the fracture toughness along the depth of boride layers.

  20. Dependence of samarium-soil interaction on samarium concentration: Implications for environmental risk assessment.

    Science.gov (United States)

    Ramírez-Guinart, Oriol; Salaberria, Aitor; Vidal, Miquel; Rigol, Anna

    2018-03-01

    The sorption and desorption behaviour of samarium (Sm), an emerging contaminant, was examined in soil samples at varying Sm concentrations. The obtained sorption and desorption parameters revealed that soil possessed a high Sm retention capacity (sorption was higher than 99% and desorption lower than 2%) at low Sm concentrations, whereas at high Sm concentrations, the sorption-desorption behaviour varied among the soil samples tested. The fractionation of the Sm sorbed in soils, obtained by sequential extractions, allowed to suggest the soil properties (pH and organic matter solubility) and phases (organic matter, carbonates and clay minerals) governing the Sm-soil interaction. The sorption models constructed in the present work along with the sorption behaviour of Sm explained in terms of soil main characteristics will allow properly assessing the Sm-soil interaction depending on the contamination scenario under study. Moreover, the sorption and desorption K d values of radiosamarium in soils were strongly correlated with those of stable Sm at low concentrations (r = 0.98); indicating that the mobility of Sm radioisotopes and, thus, the risk of radioactive Sm contamination can be predicted using data from low concentrations of stable Sm. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Mechanism of the electrochemical deposition of samarium-based coatings

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Edgar J. [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76700 Queretaro (Mexico); Ortega-Borges, Raul [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76700 Queretaro (Mexico); Godinez, Luis A. [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76700 Queretaro (Mexico); Chapman, Thomas W. [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76700 Queretaro (Mexico); Meas-Vong, Yunny [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76700 Queretaro (Mexico)]. E-mail: yunnymeas@cideteq.mx

    2006-11-12

    Samarium-based films have been shown to form from aqueous solutions on the surfaces of metallic substrates such as steel or aluminum, and their presence has been reported to decrease substantially the corresponding corrosion rate of the underlying metallic substrate. Based on previous reports on the deposition of oxides or hydroxides of the closely related element cerium, this work demonstrates that samarium films are formed following a similar mechanism, which involves as the fundamental step an increase in interfacial pH resulting from cathodic oxygen-reduction or hydrogen-evolution reactions. With cyclic voltammetry (CV), electrochemical quartz-crystal microbalance (EQCM) measurements, rotating-disk electrode (RDE) tests, and surface characterization techniques, namely, scanning electron microscopy (SEM) and X-ray surface microanalysis (EDX), the postulated mechanism was verified, and the surface morphology of the resulting films was correlated with the nature of the reduction reaction that triggers film formation.

  2. Samarium Monosulfide (SmS): Reviewing Properties and Applications

    OpenAIRE

    Sousanis, Andreas; Smet, Philippe; Poelman, Dirk

    2017-01-01

    In this review, we give an overview of the properties and applications of samarium monosulfide, SmS, which has gained considerable interest as a switchable material. It shows a pressure-induced phase transition from the semiconducting to the metallic state by polishing, and it switches back to the semiconducting state by heating. The material also shows a magnetic transition, from the paramagnetic state to an antiferromagnetically ordered state. The switching behavior between the semiconducti...

  3. Optical properties of zinc–vanadium glasses doped with samarium ...

    Indian Academy of Sciences (India)

    Abstract. Zinc–vanadium glasses doped with samarium oxide having the chemical composition Sm2O3(x). ZnO(40−x)V2O5(60)(where x = 0·1–0·5 mol%) were prepared by melt quenching method. The density of these glasses was measured by Archimedes method; the corresponding molar volumes have also been ...

  4. Synthesis of nano-pore samarium (III)-imprinted polymer for preconcentrative separation of samarium ions from other lanthanide ions via solid phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Shirvani-Arani, Simindokht [Center of Excellence in Electrochemistry, Department of Chemistry, University of Tehran, P.O.Box:14155-6455, Tehran (Iran, Islamic Republic of); Jaber Ibne Hayan Research Laboratories, Nuclear Science and Technology Research Institute, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of); Ahmadi, Seyed Javad [Jaber Ibne Hayan Research Laboratories, Nuclear Science and Technology Research Institute, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of)], E-mail: sjahmadi@aeoi.org.ir; Bahrami-Samani, Ali [Nuclear Engineering and Physics Department, Amir Kabir University, P.O.Box: 15875-4413, Tehran (Iran, Islamic Republic of); Jaber Ibne Hayan Research Laboratories, Nuclear Science and Technology Research Institute, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of); Ghannadi-Maragheh, Mohammad [Jaber Ibne Hayan Research Laboratories, Nuclear Science and Technology Research Institute, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of)

    2008-08-08

    A batch process was developed to separate samarium ions from some lanthanide ions by a novel solid phase which was prepared via the ion-imprinting technique. The samarium (III) ion-imprinted polymer (IIP) particles were synthesized by preparing the ternary complex of samarium ions with 5,7-dichloroquinoline-8-ol (DCQ) and 4-vinylpyridine (VP). Then, thermally copolymerization with styrene (functional monomer, STY) and divinylbenzene (cross-linking monomer, DVB) followed in the presence of 2-methoxy ethanol (porogen) and 2,2'-azobisisobutyronitrile (initiator, AIBN). The imprinted ion was removed by stirring the above particles with 50% (v/v) HCl to obtain the leached IIP particles. Moreover, control polymer (CP) particles were similarly prepared without the samarium ions. The unleached and leached IIP particles were characterized by X-ray diffraction (XRD), infra-red spectroscopy (IR), thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM). Finally, preconcentration and selectivity studies for samarium and the other lanthanide ions were carried out. The preconcentration of the samarium (III) traces was studied during rebinding with the leached IIP particles as a function of pH, the weight of the polymer material, the preconcentration and the elution times, the eluent volume and the aqueous phase volume. These studies indicated that the samarium (III) amount as low as 1 {mu}g, present in 200 mL, could be preconcentrated into 25 mL of 1.0 M HCl.

  5. Characterization and diffusion model for the titanium boride layers formed on the Ti6Al4V alloy by plasma paste boriding

    Science.gov (United States)

    Keddam, Mourad; Taktak, Sukru

    2017-03-01

    The present study is focused on the estimation of activation energy of boron in the plasma paste borided Ti6Al4V alloy, which is extensively used in technological applications, using an analytical diffusion model. Titanium boride layers were successfully produced by plasma paste boriding method on the Ti6Al4V alloy in the temperature range of 973-1073 K for a treatment time ranging from 3 to 7 h. The presence of both TiB2 top-layer and TiB whiskers sub-layer was confirmed by the XRD analysis and SEM observations. The surface hardness of the borided alloy was evaluated using Micro-Knoop indenter. The formation rates of the TiB2 and TiB layers were found to have a parabolic character at all applied process temperatures. A diffusion model was suggested to estimate the boron diffusivities in TiB2 and TiB layers under certain assumptions, by considering the effect of boride incubation times. Basing on own experimental data on boriding kinetics, the activation energies of boron in TiB2 and TiB phases were estimated as 136.24 ± 0.5 and 63.76 ± 0.5 kJ mol-1, respectively. Finally, the obtained values of boron activation energies for Ti6Al4V alloy were compared with the data available in the literature.

  6. Transition metal borides. Synthesis, characterization and superconducting properties

    Energy Technology Data Exchange (ETDEWEB)

    Kayhan, Mehmet

    2013-07-12

    A systematic study was done on the synthesis and superconducting properties of metal rich transition metal borides. Five different binary systems were investigated including the boride systems of niobium, tantalum, molybdenum, tungsten and rhenium. High temperature solid state methods were used in order to synthesize samples of different transition metal borides of the composition M{sub 2}B, MB, M{sub 3}B{sub 2}, MB{sub 2}, and M{sub 2}B{sub 4}. The reactions were carried out in three different furnaces with different sample containers: the electric arc (copper crucible), the high frequency induction furnace (boron nitride, tantalum or glassy carbon crucibles), and the conventional tube furnace (sealed evacuated quartz ampoules). The products obtained were characterized with X-ray powder diffractometry, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Phase analyses and crystal structure refinements using the Rietveld method and based on structure models known from literature were performed. A neutron diffraction measurement was done for W{sub 2}B{sub 4} to allow for a complete crystal structure determination, because of the presence of a heavy element like tungsten and a light element like boron that made it difficult to determine the accurate determination of the boron atom positions and occupancies from X-ray data. A new structure model for W{sub 2}B{sub 4} was proposed. Magnetic measurements in a SQUID magnetometer down to temperatures as low as 1.8 K were performed to several of the products in order to see if the transition metal borides become superconducting at low temperatures, and the results were compared with data from literature. Superconducting properties were found for the following compounds: NbB{sub 2} (T{sub C} = 3.5 K), β-MoB (T{sub C} = 2.4 K), β-WB (T{sub C} = 2.0 K), α-WB (T{sub C} = 4.3 K), W{sub 2}B{sub 4} (T{sub C} = 5.4 K), Re{sub 7}B{sub 3} (T{sub C} = 2.4 K). A relationship between the superconducting properties

  7. Effect of Fe2B boride orientation on abrasion wear resistance of Fe-B cast alloy

    Directory of Open Access Journals (Sweden)

    Da-wei Yi

    2017-07-01

    Full Text Available The microstructures and abrasion wear resistance of directional solidification Fe-B alloy have been investigated using optical microscopy, X-ray diffraction, scanning electron microscopy and laser scanning microscopy. The results show that the microstructure of as-cast Fe-B alloy consists of ferrite, pearlite and eutectic boride. After heat treatment, the microstructure is composed of boride and martensite. The plane which is perpendicular to the boride growth direction possesses the highest hardness. In two-body abrasive wear tests, the silicon carbide abrasive can cut the boride and martensite matrix synchronously, and the wear mechanism is micro cutting mechanism. The worn surface roughness and the wear weight loss both increase with the increasing contact load. Moreover, when the boride growth direction is perpendicular to the worn surface, the highest hardness plane of the boride can effectively oppose abrasion, and the martensite matrix can surround and support borides perfectly.

  8. Ionization of Samarium by Chemical Releases in the Upper Atmosphere

    Science.gov (United States)

    Siefring, C. L.; Bernhardt, P. A.; Holmes, J. M.; Pedersen, T. R.; Caton, R.; Miller, D.; Groves, K. M.

    2014-12-01

    The release of Samarium vapor into the upper atmosphere was studied using during the Air Force Research Laboratory sponsored Metal Oxide Space Cloud (MOSC) rocket launches in May 2009. The Naval Research Laboratory supported these experiments with 3-D photochemical modeling of the artificial plasma cloud including (1) reactions with atomic oxygen, (2) photo excitation, (3) photoionization, (4) dissociative recombination, and (5) ion and neutral diffusion. NRL provided the experimental diagnostic instrument on the rocket which was a dual frequency radio beacon on the rocket to measure changes in total electron content. The AFRL provided ground based diagnostics of incoherent scatter radar and optical spectroscopy and imagery. The NRL Chemical Release Model (CRM) has over 600 excited states of atomic Samarium neutrals, atomic ions, along with Samarium Oxide Ions and electrons. Diffusive transport of neutrals in cylindrical geometry and ions along magnetic field lines is computed along with the reactive flow to predict the concentrations of Sm, Sm-Ion, Sm0, and SmO Ion. Comparison of the CRM with observations demonstrates that Sm release into the upper atmosphere initially produces enhanced electron densities and SmO-Ions. The diatomic ions recombine with electrons to yield neutral Sm and O. Only the photo ionization of Sm yields a stable atomic ion that does not substantially recombine. The MOSC releases in sunlight yielded long duration ion clouds that can be replicated with the CRM. The CRM predicts that Sm releases in darkness would not produce long duration plasma clouds because of the lack of photo excitation and photoionization.

  9. Reactive Materials for Evaporating Samarium (Pre-Print)

    Science.gov (United States)

    2016-04-15

    SUBJECT TERMS energetic materials, heat sources, pyrotechnic charges, easily ionized metals 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...experiments.    Keywords:  energetic  materials, heat sources, pyrotechnic charges, easily ionized metals  1. Introduction Ejection of clouds of...results  were  negatively  affected  by  reduced  efficiency   of  release  and  ionization of samarium [8]. It is possible that not the entire charge of

  10. Electron momentum distribution and electronic response of ceramic borides

    Energy Technology Data Exchange (ETDEWEB)

    Heda, N.L. [Department of Pure and Applied Physics, University of Kota, Kota 324005 (India); Meena, B.S.; Mund, H.S. [Department of Physics, Mohanlal Sukhadia University, Udaipur 313001 (India); Sahariya, Jagrati [Department of Physics, Manipal University, Jaipur 303007 (India); Kumar, Kishor [Department of Physics, Mohanlal Sukhadia University, Udaipur 313001 (India); Ahuja, B.L., E-mail: blahuja@yahoo.com [Department of Physics, Mohanlal Sukhadia University, Udaipur 313001 (India)

    2017-03-15

    Isotropic Compton profiles of transition metal based ceramics TaB and VB have been measured using {sup 137}Cs (661.65 keV) γ-ray Compton spectrometer. The experimental momentum densities are compared with those deduced using linear combination of atomic orbitals (LCAO) with Hartree-Fock (HF), density functional theory (DFT) with Wu-Cohen generalized gradient approximation (WCGGA) and also the hybridization of HF and DFT (namely B3PW and PBE0) schemes. It is found that LCAO-DFT-WCGGA scheme based profiles give an overall better agreement with the experimental data, for both the borides. In addition, we have computed the Mulliken's population (MP) charge transfer data, energy bands, density of states and Fermi surface topology of both the borides using full potential-linearized augmented plane wave (FP-LAPW) and LCAO methods with DFT-WCGGA scheme. Cross-overs of Fermi level by the energy bands corresponding to B-2p and valence d-states of transition metals lead to metallic character in both the compounds. Equal-valence-electron-density profiles and MP analysis suggest more ionic character of VB than that of TaB.

  11. New route toward nanosized crystalline metal borides with tuneable stoichiometry and variable morphologies

    OpenAIRE

    Gouget, Guillaume; Beaunier, Patricia; Portehault, David; Sanchez, Clément

    2016-01-01

    International audience; Herein we highlight for the first time the ability to tune the stoichiometry of metal boride nanocrystals through nanoparticle synthesis in thermally stable inorganic molten salts. Two metal-boron systems are chosen as case studies: boron-poor nickel borides and boron-rich yttrium borides. We show that NiB, Ni4B3, Ni2B, Ni3B, and YB6 particles can be obtained as crystalline phases with good selectivity. Anisotropic crystallization is observed in two cases: the first bo...

  12. Phase composition and crack resistance of alloy boride layers on steel

    Science.gov (United States)

    Kholin, A. S.

    1999-04-01

    Alloying of boride layers on steel changes their phase composition, morphology, and structure. Chromium and manganese diminish the fraction of the eutectic in the layer. B-Cr and B-Mn coats do not contain monoborides. B, B-Mo, and B-Mo-W coats consist of two layers, i.e., monoborides and diborides. The other studied coats are represented by a diboride with inclusions of a monoboride. Molybdenum intensifies the texture of the FeB boride as compared with a purely boride layer; the other elements weaken it considerably.

  13. Implementation of an analytical technique for Samarium; Implementacion de una tecnica analitica para Samario

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N. [ININ, Carretera Mexico-Toluca Km. 36.5, 52045 Estado de Mexico (Mexico)

    2004-07-01

    Since the Samarium presents the same chemical properties that the plutonium, it has been used as homologous in studies that allow us to know the behavior that the plutonium presents in solution, with the advantage of working with an inactive and not very dangerous element. At the moment studies of sorption of plutonium or samarium are made on some mineral matrices that present certain surface properties. Due to the low concentrations that are used in the studies of sorption of samarium on those reagent substrates, their detection becomes very difficult for the conventional analysis media. The luminescence is a technique that can detect lower concentrations, smaller at 1 X 10{sup -} {sup 2} M, but when fluorofors are used this limit of detection increases in several orders of magnitude. In this work it has been used the arsenazo-III as fluorofor agent since it reacts in a specific way with the samarium, forming a complex that presents a proportional luminescence to the concentration of the present samarium. The advantage of making the quantification of samarium by luminescence is that it can use the same instrumental equipment to determine the speciation of the samarium sipped in the zircon. (Author)

  14. Synthesis of samarium binding bleomycin - a possible NCT radiosensitizer

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, B.M., E-mail: bmm@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Mendes, T.M.; Campos, T.P.R., E-mail: campos@nuclear.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2011-07-01

    Bleomycin (BLM) is a drug that has attractive features for the development of a new radiopharmaceutical, particularly with regard to neutron capture therapy (NCT) sensitized by Sm-149. It has the ability to chelate many metal ions. In vitro studies have shown that up to 78% of BLM present in a cell is accumulated inside the nucleus or in the nuclear membrane. In addition, this drug has higher affinity for tumor tissues than for normal tissues. Radioactive isotopes carried by this antibiotic would be taken preferentially to one important cellular targets DNA. Besides, BLM displays intrinsic anti-tumor activity - it is a chemotherapic antibiotic clinically used against some cancers. This study aimed to obtain bleomycin molecules bound to samarium (BLM-Sm) for NCT studies in vitro and in vivo. The binding technique employed in this work has great simplicity and low cost. Thin layer chromatography, high performance liquid chromatography, fast protein liquid chromatography and analysis by ICP-AES were applied to verify the binding molecule. ICP-AES results showed the presence of samarium in the sample peaks related to BLM-Sm. However, efficiency and stability of this bond needs to be investigated. (author)

  15. In Situ Solid-Gas Reactivity of Nanoscaled Metal Borides from Molten Salt Synthesis

    OpenAIRE

    Gouget, Guillaume; Debecker, Damien P.; Kim, Ara; Olivieri, Giorgia; Gallet, Jean-Jacques; Bournel, Fabrice; Thomas, Cyril; Ersen, Ovidiu; Moldovan, Simona; Sanchez, Clément; Carenco , Sophie; Portehault, David

    2017-01-01

    Metal borides have mostly been studied as bulk materials. The nanoscale provides new opportunities to investigate the properties of these materials, e.g., nanoscale hardening and surface reactivity. Metal borides are often considered stable solids because of their covalent character, but little is known on their behavior under a reactive atmosphere, especially reductive gases. We use molten salt synthesis at 750 °C to provide cobalt monoboride (CoB) nanocrystals embedded in an amorphous layer...

  16. 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".

  17. Metal Borohydrides synthesized from metal borides and metal hydrides

    DEFF Research Database (Denmark)

    Sommer, Sanna

    2014-01-01

    Aarhus C, Denmark email: gallafogh@hotmail.com / sanna-sommer@hotmail.com Magnesium boride, MgB2, ball milled with MH (M = Li, Na, Ca) followed by hydrogenation under high hydrogen pressure, readily forms the corresponding metal borohydrides, M(BH4)x (M = Li, Na, Ca) and MgH2 according to reaction scheme...... crystallization processes. In situ SR-PXD of the systems was the most promising, revealing the formation of β-Ca(BH4)2 similar to the the MgB2 – CaH2 system [5]. This connection stems from the similarities in the crystal structure of AlB2 and MgB2. MgB2 has also shown ability to form LiBH4 and NaBH4. However...

  18. Effect of boron paste thickness on the growth kinetics of Fe{sub 2}B boride layers during the boriding process

    Energy Technology Data Exchange (ETDEWEB)

    Campos, I. [ITESM-CCM Mechanical Department, Calle del Puente 222 Col. Ejidos de Huipulco, Mexico D.F. 14380 (Mexico)]. E-mail: ivan.campos@itesm.mx; Bautista, O. [ITESM-CCM Mechanical Department, Calle del Puente 222 Col. Ejidos de Huipulco, Mexico D.F. 14380 (Mexico); Ramirez, G. [IPN-SEPI-ESIME, U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F. 07738 (Mexico); Islas, M. [ITESM-CCM Mechanical Department, Calle del Puente 222 Col. Ejidos de Huipulco, Mexico D.F. 14380 (Mexico); Parra, J. de la [ITESM-CCM Mechanical Department, Calle del Puente 222 Col. Ejidos de Huipulco, Mexico D.F. 14380 (Mexico); Zuniga, L. [ITESM-CCM Mechanical Department, Calle del Puente 222 Col. Ejidos de Huipulco, Mexico D.F. 14380 (Mexico)

    2005-04-30

    Through this work we study the influence of the thickness of boron paste in the growth of Fe{sub 2}B boride layer during the paste boriding thermochemical treatment applied on AISI 1045 steel. Different thickness of boron paste over the material surface with constant temperature and time show the variability of the diffusion coefficient of boron in Fe{sub 2}B phase depending, basically, on the boron potential at the external surface of the substrate. The mobility of boron in the formed phase is determined by the balance mass equation that considers the concentration profiles in the corresponding interphases layer-substrate, the thermodynamic equilibrium in the growth of the iron boride layer and the experimental results obtained during the process.

  19. Two-level systems and negative thermal expansion of lutetium borides

    Science.gov (United States)

    Novikov, V. V.; Mitroshenkov, N. V.; Kornev, B. I.; Matovnikov, A. V.

    2017-05-01

    The heat capacity Cv(T) and unit cell volume V(T) temperature dependencies of lutetium borides LuB2 and LuB4 in the region of 2-300 K were analysed in the Debye-Einstein approximation. The characteristic temperatures of the Debye and Einstein components of boride heat capacity and thermal expansion were found. The anomalous contribution to the borides' thermal characteristics was revealed. This contribution was attributed to the influence of two-level systems (TLS), formed in the subsystem of lutetium ions due to asymmetry in the way they are surrounded by the boron atoms in the boride crystal structure. The TLS influence is revealed on heat capacity temperature dependencies by the Schottky-type maxima at Tmax LuB2 =13.8 K, Tmax LuB4 =22.7 K, as well as by the negative contribution to the borides' thermal expansion. The borides' Grüneisen parameters corresponding to the heat capacity and thermal expansion TLS anomalies are negative, and amount to several 10 s of units.

  20. Boron-Based Hydrogen Storage: Ternary Borides and Beyond

    Energy Technology Data Exchange (ETDEWEB)

    Vajo, John J. [HRL Laboratories, LLC, Malibu, CA (United States)

    2016-04-28

    DOE continues to seek reversible solid-state hydrogen materials with hydrogen densities of ≥11 wt% and ≥80 g/L that can deliver hydrogen and be recharged at moderate temperatures (≤100 °C) and pressures (≤100 bar) enabling incorporation into hydrogen storage systems suitable for transportation applications. Boron-based hydrogen storage materials have the potential to meet the density requirements given boron’s low atomic weight, high chemical valance, and versatile chemistry. However, the rates of hydrogen exchange in boron-based compounds are thus far much too slow for practical applications. Although contributing to the high hydrogen densities, the high valance of boron also leads to slow rates of hydrogen exchange due to extensive boron-boron atom rearrangements during hydrogen cycling. This rearrangement often leads to multiple solid phases occurring over hydrogen release and recharge cycles. These phases must nucleate and react with each other across solid-solid phase boundaries leading to energy barriers that slow the rates of hydrogen exchange. This project sought to overcome the slow rates of hydrogen exchange in boron-based hydrogen storage materials by minimizing the number of solid phases and the boron atom rearrangement over a hydrogen release and recharge cycle. Two novel approaches were explored: 1) developing matched pairs of ternary borides and mixed-metal borohydrides that could exchange hydrogen with only one hydrogenated phase (the mixed-metal borohydride) and only one dehydrogenated phase (the ternary boride); and 2) developing boranes that could release hydrogen by being lithiated using lithium hydride with no boron-boron atom rearrangement.

  1. Luminescent solutions and powders of new samarium complexes with N,N',O,O'-chelating ligands

    Science.gov (United States)

    Kharcheva, Anastasia V.; Nikolskiy, Kirill S.; Borisova, Nataliya E.; Ivanov, Alexey V.; Reshetova, Marina D.; Yuzhakov, Viktor I.; Patsaeva, Svetlana V.

    2016-04-01

    Imaging techniques in biology and medicine are crucial tools to obtain information on structural and functional properties of living cells and organisms. To fulfill the requirements associated with application of these techniques it appears necessary to design markers with specific characteristics. Luminescent complexes of trivalent lanthanide ions with chelating ligands are of increasing importance in biomedical applications because of their millisecond luminescence lifetime, narrow emission band, high signal-to-noise ratio and minimal photodamage to biological samples. In order to extend the available emission wavelength range the luminescent samarium chelates are highly desirable. In this study the ligands with diamides of 2,2'-bipyridin-6,6'-dicarboxylic acid were used to improve photophysical characteristics of samarium complexes. We report the luminescence characteristics of samarium complexes with novel ligands. All complexes exhibited the characteristic emission of Sm (III) ion with the lines at 565, 597, 605, 645 and 654 nm, the intensity strongly depended on the ligand. Absorption and luminescence excitation spectra of Sm (III) complexes showed main peaks in the UV range demonstrating lanthanide coordination to the ligand. The absolute lumenescence quantum yield was measured for solutions in acetonitrile with excitation at 350 nm. The largest luminescence quantum yield was found for the samarium complex Bipy 6MePy Sm (3%) being much higher that for samarium complexes reported in the literature earlier. These results prove as well that samarium chelates are potential markers for multiparametric imaging techniques.

  2. Australian manufacture of Quadramet{sup TM} (Samarium-153 EDTMP)

    Energy Technology Data Exchange (ETDEWEB)

    Wood, N.R.; Whitwell, J. [Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW (Australia). Australian Radioisotopes

    1997-10-01

    Quadramet{sup T} (Samarium-153 EDTMP) has been shown overseas to be potentially useful in the palliation of painful osteoblastic skeletal metastases and has been approved this year for general marketing in the USA. Australian Radioisotopes (ARI) has licensed this product from the Australian patent holders, Dow Chemical. Within the facilities of ARI, a hot cell has been dedicated to this product and fitted out to manufacture it weekly on a cycle related to the operating cycle of the Australian reactor HIFAR. Due to neutron flux limitations of HIFAR, the local formulation has an elemental Samarium content up to 200{mu}g/mL whereas the overseas formulation has a level of 20-46{mu}g/mL. All other specifications of the two products are essentially the same. In 1995 and 1996 a small clinical trial with 19 patients was held which demonstrated that the pharmacokinetic behaviour was also essentially the same by measuring blood clearance rates and skeletal uptake dynamics. Soft tissue uptake was also qualitatively determined. The ARI version is now the subject of an application for general marketing within Australia. Some useful characteristics of this agent are: almost complete excretion or fixation in the skeleton within 6 hours, rapid onset of clinical effect, applicability in most cases where an abnormal diagnostic bone scan correlates with painful sites, dosage can be tailored to individual patient uptake due to easy dose measurement and retreatment is quite possible. The use of this class of agents in pain palliation continues to increase. Australian manufacture of Quadramet{sup TM} provides a further option in the management of these difficult cases

  3. Electrochemical extraction of samarium from molten chlorides in pyrochemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Castrillejo, Y., E-mail: ycastril@qa.uva.es [QUIANE/Dept Quimica Analitica, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain); Fernandez, P. [QUIANE/Dept Quimica Analitica, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain); Medina, J. [Dept Fisica Materia Condensada Cristalografia y Mineralogia, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain); Hernandez, P. [Centro de Investigaciones Quimicas, Universidad Autonoma del Estado de Hidalgo, Carr. Pachuca-Tulancingo Km. 4.5, C.P. 42076 Pachuca, Hidalgo (Mexico); Barrado, E. [QUIANE/Dept Quimica Analitica, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain)

    2011-10-01

    This work concerns the electrochemical extraction of samarium from molten chlorides. In this way, the electrochemical behaviour of samarium ions has been investigated in the eutectic LiCl-KCl at the surface of tungsten, aluminium and aluminium coated tungsten electrodes. On a W inert electrode the electro-reduction of Sm(III) takes place in only one soluble-soluble electrochemical step Sm(III)/Sm(II). The electrochemical system Sm(II)/Sm(0) has not been observed within the electrochemical window, because of the prior reduction of Li(I) ions from the solvent, which inhibits the electro-extraction of Sm species from the salt on such a substrate. Sm metal in contact with the melt react to give Li(0) according to the reaction: Sm(0) + 2Li(I) {r_reversible} Sm(II) + 2Li(0). On the contrary, on reactive Al electrodes the electrochemical system Sm(II)/Sm(0) was observed within the electroactive range. The potential shift of the redox couple is caused by the decrease of Sm activity in the metal phase due to the formation of Sm-Al alloys at the interface. The formation mechanism of the intermetallic compounds was studied in a melt containing: (i) both Sm(III) and Al(III) ions, using W and Al coated tungsten electrodes, and (ii) Sm(III) ions using an Al electrode. Analysis of the samples after potentiostatic electrolysis by X-ray diffraction and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), allowed the identification of Al{sub 3}Sm and Al{sub 2}Sm.

  4. In Situ Solid-Gas Reactivity of Nanoscaled Metal Borides from Molten Salt Synthesis.

    Science.gov (United States)

    Gouget, Guillaume; Debecker, Damien P; Kim, Ara; Olivieri, Giorgia; Gallet, Jean-Jacques; Bournel, Fabrice; Thomas, Cyril; Ersen, Ovidiu; Moldovan, Simona; Sanchez, Clément; Carenco, Sophie; Portehault, David

    2017-08-07

    Metal borides have mostly been studied as bulk materials. The nanoscale provides new opportunities to investigate the properties of these materials, e.g., nanoscale hardening and surface reactivity. Metal borides are often considered stable solids because of their covalent character, but little is known on their behavior under a reactive atmosphere, especially reductive gases. We use molten salt synthesis at 750 °C to provide cobalt monoboride (CoB) nanocrystals embedded in an amorphous layer of cobalt(II) and partially oxidized boron as a model platform to study morphological, chemical, and structural evolutions of the boride and the superficial layer exposed to argon, dihydrogen (H2), and a mixture of H2 and carbon dioxide (CO2) through a multiscale in situ approach: environmental transmission electron microscopy, synchrotron-based near-ambient-pressure X-ray photoelectron spectroscopy, and near-edge X-ray absorption spectroscopy. Although the material is stable under argon, H2 triggers at 400 °C decomposition of CoB, leading to cobalt(0) nanoparticles. We then show that H2 activates CoB for the catalysis of CO2 methanation. A similar decomposition process is also observed on NiB nanocrystals under oxidizing conditions at 300 °C. Our work highlights the instability under reactive atmospheres of nanocrystalline cobalt and nickel borides obtained from molten salt synthesis. Therefore, we question the general stability of metal borides with distinct compositions under such conditions. These results shed light on the actual species in metal boride catalysis and provide the framework for future applications of metal borides in their stability domains.

  5. New route toward nanosized crystalline metal borides with tuneable stoichiometry and variable morphologies.

    Science.gov (United States)

    Gouget, Guillaume; Beaunier, Patricia; Portehault, David; Sanchez, Clément

    2016-10-06

    Herein we highlight for the first time the ability to tune the stoichiometry of metal boride nanocrystals through nanoparticle synthesis in thermally stable inorganic molten salts. Two metal-boron systems are chosen as case studies: boron-poor nickel borides and boron-rich yttrium borides. We show that NiB, Ni4B3, Ni2B, Ni3B, and YB6 particles can be obtained as crystalline phases with good selectivity. Anisotropic crystallization is observed in two cases: the first boron-rich YB4 nanorods are reported, while boron-poor NiB nanoparticles show a peculiar crystal habit, as they are obtained as spheres with uniaxial defects related to the crystal structure. Crystallization mechanisms are proposed to account for the appearance of these two kinds of anisotropy at the nanoscale.

  6. Hardness optimization of boride diffusion layer on Astm F-75 alloy using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Arguelles O, J. L.; Corona R, M. A. [Universidad Autonoma de San Luis Potosi, Doctorado Institucional en Ingenieria y Ciencia de Materiales, San Luis Potosi 78000, SLP (Mexico); Marquez H, A.; Saldana R, A. L.; Saldana R, A. [Universidad de Guanajuato, Ingenieria Mecanica Agricola DICIVA, Irapuato, Guanajuato 36500 (Mexico); Moreno P, J., E-mail: amarquez@ugto.mx [Universidad de Guanajuato, Departamento de Minas, Metalurgia y Geologia, Ex-Hacienda San Matias s/n, Guanajuato, Guanajuato 36020 (Mexico)

    2017-11-01

    In this study, the Response Surface Methodology (Rsm) and Central Composite Design (Ccd) were used to optimize the hardness of boride diffusion layer on Astm F-75 alloy (also called Haynes alloy). A boronizing thermochemical treatment was carried out at different temperatures and for different time periods. Hardness tests were conducted. The boride diffusion layer was verified by the X-ray diffraction (XRD) analysis indicating the formation of Co B, Co{sub 2}B, Cr B and Mo{sub 2}B phases. An optimal hardness of 3139.7 Hv was obtained for the samples subjected to the boriding process for a duration of 6.86 h at 802.4 degrees Celsius. (Author)

  7. Metal-boride phase formation on tungsten carbide (WC-Co) during microwave plasma chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Jamin M.; Catledge, Shane A., E-mail: catledge@uab.edu

    2016-02-28

    Graphical abstract: - Highlights: • A detailed phase analysis after PECVD boriding shows WCoB, CoB and/or W{sub 2}CoB{sub 2}. • EDS of PECVD borides shows boron diffusion into the carbide grain structure. • Nanoindentation hardness and modulus of borides is 23–27 GPa and 600–780 GPa. • Scratch testing shows hard coating with cracking at 40N and spallation at 70N. - Abstract: Strengthening of cemented tungsten carbide by boriding is used to improve the wear resistance and lifetime of carbide tools; however, many conventional boriding techniques render the bulk carbide too brittle for extreme conditions, such as hard rock drilling. This research explored the variation in metal-boride phase formation during the microwave plasma enhanced chemical vapor deposition process at surface temperatures from 700 to 1100 °C. We showed several well-adhered metal-boride surface layers consisting of WCoB, CoB and/or W{sub 2}CoB{sub 2} with average hardness from 23 to 27 GPa and average elastic modulus of 600–730 GPa. The metal-boride interlayer was shown to be an effective diffusion barrier against elemental cobalt; migration of elemental cobalt to the surface of the interlayer was significantly reduced. A combination of glancing angle X-ray diffraction, electron dispersive spectroscopy, nanoindentation and scratch testing was used to evaluate the surface composition and material properties. An evaluation of the material properties shows that plasma enhanced chemical vapor deposited borides formed at substrate temperatures of 800 °C, 850 °C, 900 °C and 1000 °C strengthen the material by increasing the hardness and elastic modulus of cemented tungsten carbide. Additionally, these boride surface layers may offer potential for adhesion of ultra-hard carbon coatings.

  8. Optical analysis of samarium doped sodium bismuth silicate glass.

    Science.gov (United States)

    Thomas, V; Sofin, R G S; Allen, M; Thomas, H; Biju, P R; Jose, G; Unnikrishnan, N V

    2017-01-15

    Samarium doped sodium bismuth silicate glass was synthesized using the melt quenching method. Detailed optical spectroscopic studies of the glassy material were carried out in the UV-Vis-NIR spectral range. Using the optical absorption spectra Judd-Ofelt (JO) parameters are derived. The calculated values of the JO parameters are utilized in evaluating the various radiative parameters such as electric dipole line strengths (Sed), radiative transition probabilities (Arad), radiative lifetimes (τrad), fluorescence branching ratios (β) and the integrated absorption cross- sections (σa) for stimulated emission from various excited states of Sm3+‡ ion. The principal fluorescence transitions are identified by recording the fluorescence spectrum. Our analysis revealed that the novel glassy system has the optimum values for the key parameters viz. spectroscopic quality factor, optical gain, stimulated emission cross section and quantum efficiency, which are required for a high performance optical amplifier. Calculated chromaticity co-ordinates (0.61, 0.38) also confirm its application potential in display devices. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Samarium Monosulfide (SmS): Reviewing Properties and Applications.

    Science.gov (United States)

    Sousanis, Andreas; Smet, Philippe F; Poelman, Dirk

    2017-08-16

    In this review, we give an overview of the properties and applications of samarium monosulfide, SmS, which has gained considerable interest as a switchable material. It shows a pressure-induced phase transition from the semiconducting to the metallic state by polishing, and it switches back to the semiconducting state by heating. The material also shows a magnetic transition, from the paramagnetic state to an antiferromagnetically ordered state. The switching behavior between the semiconducting and metallic states could be exploited in several applications, such as high density optical storage and memory materials, thermovoltaic devices, infrared sensors and more. We discuss the electronic, optical and magnetic properties of SmS, its switching behavior, as well as the thin film deposition techniques which have been used, such as e-beam evaporation and sputtering. Moreover, applications and possible ideas for future work on this material are presented. Our scope is to present the properties of SmS, which were mainly measured in bulk crystals, while at the same time we describe the possible deposition methods that will push the study of SmS to nanoscale dimensions, opening an intriguing range of applications for low-dimensional, pressure-induced semiconductor-metal transition compounds.

  10. Excitation induced spectroscopic study and quenching effect in cerium samarium codoped lithium aluminoborate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Parvinder; Kaur, Simranpreet [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Singh, Gurinder Pal [Department of Physics, Khalsa College, Amritsar 143002 (India); Arora, Deepawali; Kumar, Sunil [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Singh, D.P., E-mail: dpsinghdr@yahoo.com [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India)

    2016-08-15

    Lithium aluminium borate host has been codoped with cerium and samarium to prepare glass by conventional melt quench technique. Their structural and spectroscopic investigation has been carried out using XRD, FTIR and density measurements. The UV‐Vis absorption spectra and fluorescence spectra (λ{sub exc}.=380 nm and 400 nm) have been studied for spectroscopic analysis. The amorphous nature of the prepared samples is shown by XRD. The density is increasing with addition of cerium at the expense of aluminium, keeping other components constant. FTIR study also shows the presence of compact and stable tetrahedral BO{sub 4} units thus supporting the density results. The UV‐ Vis absorption spectra show a shift of optical absorption edge towards longer wavelength along with an increase in intensity of peaks with rising samarium concentration. The fluorescence spectra show a blue shift and subsequent suppression of cerium peaks with addition of samarium.

  11. Effect of samarium doping on the dielectric behavior of barium zircomium titanate ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Badapanda, T., E-mail: badapanda.tanmaya@gmail.com [Department of Physics, C.V. Raman College of Engineering, Bhubaneswar, Odisha-752054 (India); Sarangi, S.; Behera, B. [School of Physics, Sambalpur University, Jyoti Vihar Sambalpur, Odisha-768019 (India); Anwar, S. [Colloids and Materials Chemistry, Institute of Minerals and Materials Technology, Bhubaneswar, Odisha-751013 (India); Sinha, T. P. [Department of Physics, Bose Institute, Kolkata-700009 (India)

    2014-04-24

    Samarium doped Barium Zirconium Titanate ceramic with general formula Ba{sub 1−x}Sm{sub 2x/3}Zr{sub 0.05}Ti{sub 0.95}O{sub 3} [x=0.0,0.01,0.02,0.03,0.04] has been prepared by high energy ball milling. The X-ray diffraction (XRD) patterns confirmed that these ceramics have a single phase with perovskite-type upto x≤0.03 and a small secondary phase exist at x=0.04. The temperature dependent dielectric study shows a ferroelectric phase transition and transition temperature decreases with an increase in the Samarium content.

  12. Lithium Bromide/Water as Additives in Dearomatizing Samarium-Ketyl (Hetero)Arene Cyclizations.

    Science.gov (United States)

    Rao, Chintada Nageswara; Bentz, Christoph; Reissig, Hans-Ulrich

    2015-11-02

    New conditions for dearomatizing samarium-ketyl (hetero)arene cyclizations are reported. In many examples of these samarium diiodide-mediated reactions, lithium bromide and water can be used as additives instead of the carcinogenic and mutagenic hexamethylphosphoramide (HMPA). The best results were obtained for the cyclizations of N-acylated indole derivatives delivering the expected indolines in good yields and excellent diastereoselectivities. A new type of cyclization delivering indolyl-substituted allene derivatives is also described. The scope and limitations of the lithium bromide/water system are discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Surface hardening of St41 low carbon steel by using the hot-pressing powder-pack boriding method

    Science.gov (United States)

    Sutrisno, Soegijono, Bambang

    2014-03-01

    This research describes a powder-pack boriding process by using hot-pressing technic for St41 low carbon steel which will improve the hardness on the substrate by forming boride layer solid solution. Those method can reduce the operational cost of the research if it is compared by the conventional method with the asmospheric condition both vacuum system and gas inert condition. The concept of boriding by hot-pressing technic was verified in a laboratory scale. Welldefined and reusedable technic was achieved by using the stainless steel 304 as the container and sealed with a 5 ton pressure. This container was filled boronizing powder consisting of 5%B4C, 90%SiC, and 5%KBF4 to close the St41 low carbon steel specimen inside the container. The St41 boriding specimen was treated at the temperature of 900°C for 8 hours. The boride layer on the substrate was found as FeB and Fe2B phase with the hardness about 1800 HV. This value was more than ten times if compared with the untreated specimen that only had the hardness of 123 HV. Depend on heat treatment temperature, heat treatment time, and powder-pack boriding pressure, the depth of boride layer range from 127 to 165 μm, leading to a diffusion controlled process.

  14. Growth kinetics of boride layers formed on 99.0% purity nickel

    Indian Academy of Sciences (India)

    1Department of Metallurgical and Materials Engineering, Faculty of Technology, Afyon Kocatepe University,. 03200 Afyonkarahisar, Turkey. 2Laboratory of Materials Technology, Faculty of Mechanical Engineering and Process Engineering, USTHB, B.P. No. 32, ... in a negative effect on the boride layer in terms of both.

  15. Micro-Abrasion Wear Resistance of Borided 316L Stainless Steel and AISI 1018 Steel

    Science.gov (United States)

    Reséndiz-Calderon, C. D.; Rodríguez-Castro, G. A.; Meneses-Amador, A.; Campos-Silva, I. E.; Andraca-Adame, J.; Palomar-Pardavé, M. E.; Gallardo-Hernández, E. A.

    2017-11-01

    The 316L stainless steel has high corrosion resistance but low tribological performance. In different industrial sectors (biomedical, chemical, petrochemical, and nuclear engineering), improvement upon wear resistance of 316L stainless steel components using accessible and inexpensive methods is critical. The AISI 1018 steel is widely used in industry, but its tribological performance is not the best among steels. Therefore, in this study the behavior of the borided 316L stainless steel and 1018 steel is evaluated under micro-abrasion wear. The boriding was carried out at 1223 K over 6 h of exposure time, resulting in a biphase layer composed of FeB/Fe2B phases. In order to evaluate Fe2B phase with no influence from FeB phase, AISI 1018 steel samples were borided at 1273 K for over 20 min and then diffusion annealed at 1273 K over 2 h to obtain a Fe2B mono-phase layer. Micro-abrasion wear resistance was evaluated by a commercial micro-abrasion testing rig using a mix of F-1200 SiC particles with deionized water as abrasive slurry. The obtained wear rates for FeB and Fe2B phases and for the 316L stainless steel were compared. Wear resistance of 316L stainless steel increases after boriding. The wear mechanisms for both phases and for the stainless steel were identified. Also, transient conditions for rolling and grooving abrasion were determined for the FeB and Fe2B phases.

  16. Ultra-Fast Boriding in High-Temperature Materials Processing Industries

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-12-01

    This factsheet describes a research project whose main objective is to further develop, optimize, scale-up, and commercialize an ultra-fast boriding (also referred to as “boronizing”) process that can provide much higher energy efficiency, productivity, and near-zero emissions in many of the high-temperature materials processing industries.

  17. Micro-Abrasion Wear Resistance of Borided 316L Stainless Steel and AISI 1018 Steel

    Science.gov (United States)

    Reséndiz-Calderon, C. D.; Rodríguez-Castro, G. A.; Meneses-Amador, A.; Campos-Silva, I. E.; Andraca-Adame, J.; Palomar-Pardavé, M. E.; Gallardo-Hernández, E. A.

    2017-10-01

    The 316L stainless steel has high corrosion resistance but low tribological performance. In different industrial sectors (biomedical, chemical, petrochemical, and nuclear engineering), improvement upon wear resistance of 316L stainless steel components using accessible and inexpensive methods is critical. The AISI 1018 steel is widely used in industry, but its tribological performance is not the best among steels. Therefore, in this study the behavior of the borided 316L stainless steel and 1018 steel is evaluated under micro-abrasion wear. The boriding was carried out at 1223 K over 6 h of exposure time, resulting in a biphase layer composed of FeB/Fe2B phases. In order to evaluate Fe2B phase with no influence from FeB phase, AISI 1018 steel samples were borided at 1273 K for over 20 min and then diffusion annealed at 1273 K over 2 h to obtain a Fe2B mono-phase layer. Micro-abrasion wear resistance was evaluated by a commercial micro-abrasion testing rig using a mix of F-1200 SiC particles with deionized water as abrasive slurry. The obtained wear rates for FeB and Fe2B phases and for the 316L stainless steel were compared. Wear resistance of 316L stainless steel increases after boriding. The wear mechanisms for both phases and for the stainless steel were identified. Also, transient conditions for rolling and grooving abrasion were determined for the FeB and Fe2B phases.

  18. One-step synthesis of samarium-doped ceria and its CO catalysis

    Indian Academy of Sciences (India)

    The samarium-doped ceria (SDC) nanospheres were prepared by the one-step hydrothermal method and characterized by transmission electron microscope, scanning electron microscope, powder X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive spectrometer and Raman spectra. According to the ...

  19. A spectroscopic comparison of samarium-doped LiYF4 and KY3F10

    NARCIS (Netherlands)

    Wells, J. P. R.; Sugiyama, A.; Han, T. P. J.; Gallagher, H. G.

    2000-01-01

    Laser selective excitation and fluorescence has been performed on LiYF4 and KY3F10 doped with samarium ions. In LiYF4, a single, tetragonal symmetry center associated with isovalent substitution of Sm3+ with lattice yttrium ions is present. By contrast, three Sm2+ centres and a single, tetragonal

  20. Signs of superconductivity at 110 K on inclusions of TiB sub k boride phases into titanium matrix

    CERN Document Server

    Volkov, V V; Berzverkhij, P P; Martynets, V G; Matizen, E V

    2002-01-01

    Verification of theoretical forecasts on the possibility of the high-temperature superconductivity of the high-temperature superconductivity (HTSC) in the TiB sub k titanium borides is accomplished. It is established that the jump-like change in the temperature dependence of the electric resistance R(T) at 110 K takes place on the titanium samples, the surfaces whereof are coated with the borides diffusion layers of the TiB sub k variable in-depth composition. This proves the presence of the borides diffusion layers are applied onto the metallic titanium by means of treating its surface with the B sub 2 H sub 6 + H sub 2 gases mixture at the temperature of 610-700 deg C with the subsequent annealing in vacuum. The boride layers composition is studied through the mass-spectrometry method

  1. The Relationship of the Chemical Bonding Topology of High Critical Temperature Copper Oxide Superconductors to that of the Chevrel Phases and the Ternary Lanthanide Rhodium Borides.

    Science.gov (United States)

    1987-12-11

    to those of the ternary molybdenum chalcogenides and ternary lanthanide rhodium borides in which the conducting skeleton is constructed from metal...Bonding Topology of High Critical Temperature Copper Oxide Superconductors to That of The Chevrel Phases and the Ternary Lanthanide Rhodium Borides by R...REPORT NUMBER P Rhodium Borides 7 AUTHOR(s ) S. CONTRACT OR GRANT NUMIER(*) f, % .0, R.B. King N00014-84-K-0365 S. PERFORMING ORGANIZATION NAME AND

  2. The Use of a Flexible Calix[4]arene Template to Stabilize a Cyclooctatetraindiyl Samarium-Potassium Complex

    Directory of Open Access Journals (Sweden)

    Geoffroy Guillemot

    2013-01-01

    Full Text Available A sandwich compound of cyclooctatetraendiyl (COT2− samarium-potassium was synthesized and analyzed using a flexible calix[4]arene dianion. This compound, [p-tBu-calix[4]-(OMe2(O2]arenediyl-samarium-(η8-cyclooctatetraendiyl-potassium (tetrahydrofurane3, is constructed as a linear sequence L-Sm--K-, where L, , and are specific ligands with L = O,O-dimethyl-calix[4]arene2−, = cyclo-octatetraendiyl, and = tetrahydrofurane templates.

  3. Friction and wear of radiofrequency-sputtered borides, silicides, and carbides

    Science.gov (United States)

    Brainard, W. A.; Wheeler, D. R.

    1978-01-01

    The friction and wear properties of several refractory compound coatings were examined. These compounds were applied to 440 C bearing steel surfaces by radiofrequency (RF) sputtering. The refractory compounds were the titanium and molybdenum borides, the titanium and molybdenum silicides, and the titanium, molybdenum, and boron carbides. Friction testing was done with a pin-on-disk wear apparatus at loads from 0.1 to 5.0 newtons. Generally, the best wear properties were obtained when the coatings were bias sputtered onto 440 C disks that had been preoxidized. Adherence was improved because of the better bonding of the coatings to the iron oxide formed during preoxidation. As a class the carbides provided wear protection to the highest loads. Titanium boride coatings provided low friction and good wear properties to moderate loads.

  4. Electrosynthesis of tantalum borides in oxygen-free and oxygen-containing fluoride melts

    DEFF Research Database (Denmark)

    Polyakova, L.P.; Polyakov, E.G.; Makarova, O.V.

    2001-01-01

    Results of electrosynthesis of tantalum borides in fluoride and oxyfluoride melts are compared. It is shown that the single-phase X-ray-amorphous micro-layered coatings form only in the latter case. Linear and square-wave voltammetry, complemented by X-ray diffraction analysis, IR spectroscopy......, and OC, reveals that the reason for their formation is the cathodic reduction of heteronuclear tantalum and boron complexes....

  5. Preparation of molybdenum borides by combustion synthesis involving solid-phase displacement reactions

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, C.L. [Department of Mechanical and Automation Engineering, Da-Yeh University, 112 Shan-Jiau Rd., Da-Tsuen, Changhua 51505, Taiwan (China)], E-mail: clyeh@mail.dyu.edu.tw; Hsu, W.S. [Department of Mechanical and Automation Engineering, Da-Yeh University, 112 Shan-Jiau Rd., Da-Tsuen, Changhua 51505, Taiwan (China)

    2008-06-12

    Preparation of molybdenum borides of five different phases in the Mo-B binary system (including Mo{sub 2}B, MoB, MoB{sub 2}, Mo{sub 2}B{sub 5}, and MoB{sub 4}) was performed by self-propagating high-temperature synthesis (SHS) with two kinds of the reactant samples. When elemental powder compacts with an exact stoichiometry corresponding to the boride phase were employed, self-sustaining reaction was only achieved in the sample with Mo:B = 1:1 and nearly single-phase MoB was yielded. Therefore, the other four boride compounds were prepared from the reactant compacts composed of MoO{sub 3}, Mo, and B powders, within which the displacement reaction of MoO{sub 3} with boron was involved in combustion synthesis. Experimental evidence shows that the extent of displacement reaction in the overall reaction has a significant impact on sustainability of the synthesis reaction, combustion temperature, reaction front velocity, and composition of the end product. An increase in the solid-phase displacement reaction taking place during the SHS process contributes more heat flux to the synthesis reaction, thus resulting in the increase of combustion temperature and enhancement of the reaction front velocity. Based upon the XRD analysis, formation of Mo{sub 2}B, MoB{sub 2}, and Mo{sub 2}B{sub 5} as the dominant boride phase in the end product was successful through the SHS reaction with powder compacts under appropriate stoichiometries between MoO{sub 3}, Mo, and B. However, a poor conversion was observed in the synthesis of MoB{sub 4}. The powder compact prepared for the production of MoB{sub 4} yielded mostly Mo{sub 2}B{sub 5}.

  6. Influence of Re Concentration on the Mechanical Properties of Tungsten Borides from First-Principles Calculations

    Science.gov (United States)

    Pan, Yong; Lin, Yuanhua

    2017-10-01

    Tungsten borides are promising high-temperature materials. However, the structure and hardening mechanisms of tungsten boride are still great challenges. To solve the problems, we apply the first-principles method to study the structure of WB3 and explore the influence of alloying element Re on the mechanical properties of WB3. The calculated Vickers hardness of WB3 is 39.1 GPa. We further find that a low concentration of Re can improve the hardness of WB3, which is in good agreement with the experimental result. However, the hardness and elastic properties of WB3 decrease gradually with increasing Re concentration. The calculated results show that the structure and hardness of WB3 are attributed to the B-B hexagonal prism. A high concentration of Re weakens the charge interaction between the B-B atoms, and reduces the mechanical properties of WB3. Therefore, we can adjust the alloy concentration to improve the Vickers hardness of transition metal borides.

  7. Structure of superhard tungsten tetraboride: A missing link between MB2 and MB12 higher borides

    Science.gov (United States)

    Lech, Andrew T.; Turner, Christopher L.; Mohammadi, Reza; Tolbert, Sarah H.; Kaner, Richard B.

    2015-01-01

    Superhard metals are of interest as possible replacements with enhanced properties over the metal carbides commonly used in cutting, drilling, and wear-resistant tooling. Of the superhard metals, the highest boride of tungsten—often referred to as WB4 and sometimes as W1–xB3—is one of the most promising candidates. The structure of this boride, however, has never been fully resolved, despite the fact that it was discovered in 1961—a fact that severely limits our understanding of its structure–property relationships and has generated increasing controversy in the literature. Here, we present a new crystallographic model of this compound based on refinement against time-of-flight neutron diffraction data. Contrary to previous X-ray–only structural refinements, there is strong evidence for the presence of interstitial arrangements of boron atoms and polyhedral bonding. The formation of these polyhedra—slightly distorted boron cuboctahedra—appears to be dependent upon the defective nature of the tungsten-deficient metal sublattice. This previously unidentified structure type has an intermediary relationship between MB2 and MB12 type boride polymorphs. Manipulation of the fractionally occupied metal and boron sites may provide insight for the rational design of new superhard metals. PMID:25733870

  8. Structure of superhard tungsten tetraboride: a missing link between MB2 and MB12 higher borides.

    Science.gov (United States)

    Lech, Andrew T; Turner, Christopher L; Mohammadi, Reza; Tolbert, Sarah H; Kaner, Richard B

    2015-03-17

    Superhard metals are of interest as possible replacements with enhanced properties over the metal carbides commonly used in cutting, drilling, and wear-resistant tooling. Of the superhard metals, the highest boride of tungsten--often referred to as WB4 and sometimes as W(1-x)B3--is one of the most promising candidates. The structure of this boride, however, has never been fully resolved, despite the fact that it was discovered in 1961--a fact that severely limits our understanding of its structure-property relationships and has generated increasing controversy in the literature. Here, we present a new crystallographic model of this compound based on refinement against time-of-flight neutron diffraction data. Contrary to previous X-ray-only structural refinements, there is strong evidence for the presence of interstitial arrangements of boron atoms and polyhedral bonding. The formation of these polyhedral--slightly distorted boron cuboctahedra--appears to be dependent upon the defective nature of the tungsten-deficient metal sublattice. This previously unidentified structure type has an intermediary relationship between MB2 and MB12 type boride polymorphs. Manipulation of the fractionally occupied metal and boron sites may provide insight for the rational design of new superhard metals.

  9. Solar nebula heterogeneity in p-process samarium and neodymium isotopes.

    Science.gov (United States)

    Andreasen, Rasmus; Sharma, Mukul

    2006-11-03

    Bulk carbonaceous chondrites display a deficit of approximately 100 parts per million (ppm) in 144Sm with respect to other meteorites and terrestrial standards, leading to a decrease in their 142Nd/144Nd ratios by approximately 11 ppm. The data require that samarium and neodymium isotopes produced by the p process associated with photodisintegration reactions in supernovae were heterogeneously distributed in the solar nebula. Other samarium and neodymium isotopes produced by rapid neutron capture (r process) in supernovae and by slow neutron capture (s process) in red giants were homogeneously distributed. The supernovae sources supplying the p- and r-process nuclides to the solar nebula were thus disconnected or only weakly connected.

  10. Samarium(II) iodide-mediated reductive annulations of ketones bearing a distal vinyl epoxide moiety

    Energy Technology Data Exchange (ETDEWEB)

    Molander, G.A.; Shakya, S.R. [Univ. of Colorado, Boulder, CO (United States)

    1996-08-23

    It was found that samarium (II) iodide promotes the intramolecular coupling of ketones with distal epoxy olefins while in the presence of hexamethylphosphoramide (HPMA). A number of epoxide compounds (1 a-k) fragment to form carbocycles with allylic alcohol side chains with high diastereoselectivity (2 a-k). Substituting tetramethylguanidine for HPMA reduces the diastereoselectivity. Adding Pd(0) as a catalyst reverses the diastereoselective sense. 40 refs., 1 tab.

  11. A temporal three-dimensional simulation of samarium release in the ionosphere

    Science.gov (United States)

    Zhao, Hai-Sheng; Feng, Jie; Xu, Zheng-Wen; Wu, Jian; Wu, Zhen-Sen; Xu, Bin; Xue, Kun; Xu, Tong; Hu, Yan-Li

    2016-10-01

    For understanding plasma processes of the ionosphere and magnetosphere, the alkali and alkaline-earth metals are usually released in space for artificially increasing the electron density. However, it is a limitation that these releases must be in sunlight where the photoionization can take place. In recent years, the lanthanide metals, such as samarium, have been released to produce electrons in reaction with atomic oxygen in the upper space. The reaction could proceed without sunlight so that the restriction on experimental periods is broken. Unfortunately, any sophisticated models even preliminary ones are unavailable yet in the literature. A temporal three-dimensional model is presented for the samarium release in detail with respect to various altitudes and mass. Especially, the plasma diffusion equation is remarkably extended from 2-D to 3-D by importing the influence of geomagnetic declination, which could be also useful for other chemical releases. The field-aligned terms are brought so as to the presented model can describe the diffusion along the geomagnetic field subtly. On the basis of the presented model, behaviors of radio waves propagating through the release area are simulated by using ray tracing. This model could be as the theoretical support for samarium releases, and it also helpful for the research on the generation and evolution of the ionosphere irregularities.

  12. Effect of High Configuration Entropy and Rare Earth Addition on Boride Precipitation and Mechanical Properties of Multi-principal-Element Alloys

    Science.gov (United States)

    Zhang, H.; Zhong, X. C.; He, Y. Z.; Li, W. H.; Wu, W. F.; Chen, G.; Guo, S.

    2017-08-01

    A series of multi-principal-element (MPE) alloys have been prepared by adding Ni, Mn, Al, Cu and Y into the reference CoCrFe-B alloy. The microstructure and mechanical properties of these MPE alloys have been investigated thoroughly. It is found that the addition of the elements can inhibit boride precipitation in the designed alloys and the solid solution strengthening effect induced by interstitial boron atoms is more significant than that by boride precipitation. The MPE alloys with the fcc phase as the main solid solution phase have a higher boron solubility and hence less boride precipitation, than those with the bcc phase as the main solid solution phase. The addition of yttrium can improve the boron solubility, decrease boride precipitation, control the boride morphology and, importantly, simultaneously improve the compressive strength and ductility of boron-containing MPE alloys.

  13. Liquid–liquid anion exchange extraction studies of samarium(III from salicylate media using high molecular weight amine

    Directory of Open Access Journals (Sweden)

    Aniruddha M. Mandhare

    2015-07-01

    Full Text Available Liquid–liquid extraction and separation of samarium(III were carried out by using 0.025 mol dm−3 2-octylaminopyridine(2-OAP in xylene at 298 K. The extraction behavior of samarium was studied as a function of pH, weak acid concentration, extractant concentration, diluent, and equilibration time. Samarium was quantitatively extracted at pH 7.5 to 10.0 from 0.01 mol dm−3 sodium salicylate solution with 0.025 mol dm−3 2-OAP. The possible composition of the extracted species in organic phase has been determined by using model of slope analysis method and extraction mechanism was found to proceed via an anion exchange mechanism. The stripping efficiency was found to be quantitative in HNO3, HCl and CH3COOH. The robustness of the procedure was demonstrated by the average recoveries obtained (>99.6% for samarium(III extraction in the presence of several cations and anions which are commonly associated with it. The proposed method facilitates the separation and determination of samarium(III from binary and synthetic mixtures. The various thermodynamic functions like free energy (ΔG, enthalpy (ΔH and entropy (ΔS of extraction mechanism were discussed.

  14. 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

  15. Response of boride coating on the Ti-6Al-4V alloy to corrosion and fretting corrosion behavior in Ringer's solution for bio-implant application

    Science.gov (United States)

    Bose, Sivakumar; Pathak, Lokesh Chandra; Singh, Raghuvir

    2018-03-01

    Corrosion and fretting corrosion of boride coating on Ti-6Al-4V (TAV) are investigated in Ringer's solution for bio-implant applications. Boride coatings are fabricated as a function of temperature (900-1100 °C) and soaking time (1-5 h). Coatings are characterized for phase evaluation, microstructural analysis, thickness and microhardness measurement. The coating contained TiB2 and TiB whiskers as outermost and inner layers respectively. The increasing thickness of outer TiB2 at a relatively higher boriding temperature and time impeded the TiB formation. A large microhardness value of ∼3248 Hv15gf at the outermost surface (corrosion resistance of coating produced at increased temperature and time of boriding, yet remained lower than the resistance of bare TAV alloy. The formation of B2O3 and absence of Al2O3 on the surface, as investigated by X-ray photoelectron spectroscopy (XPS), are attributed to an inferior corrosion resistance of the borided TAV. The increase in corrosion resistance with the TiB2 coating thickness is attributed to thickening of the inner passive film formed on borided TAV. A large decrease in fretting damage after boride coating is due to the decline in a synergistic parameter.

  16. Samarium(II) iodide-mediated intramolecular conjugate additions of alpha,beta-unsaturated lactones.

    Science.gov (United States)

    Molander, Gary A; St Jean, David J

    2002-05-31

    Samarium(II) iodide, in the presence of catalytic amounts of nickel(II) iodide, has been used to promote intramolecular conjugate additions of alkyl halides onto alpha,beta-unsaturated lactones. This process has been shown to be applicable to a number of alpha,beta-unsaturated lactones, including tetrasubstituted olefins, and has been demonstrated to be quite general for the formation of saturated bicyclic and tricyclic lactones. The method presented herein provides a mild, efficient process to form structurally complex lactones from simple precursors.

  17. Increasing the Surface Hardness of Cast Iron by Electrodeposition of Borides in Molten Salts

    Directory of Open Access Journals (Sweden)

    Al-Azzawi A.H.

    2017-06-01

    Full Text Available In this paper the electrodeposition of boron on the surface of cast iron as a coating is applied to increase the hardness and protect the substrate against abrasive wear. The boron containing coating was synthesized by electrodeposition process from a NaCl-KCl (1:1 mol-10 w%NaF-10w% KBF4 molten salt. The effect of electrolysis parameters (temperature and time on the hardness is presented; the current density varied in the range −37 – −4.5 mA/cm2, allowing perfect coverage of and respect for dimensions. The electrochemical process was carried out at different temperatures (750°C-900°C and for different periods of time (5-10 hours. Depending on the current density and duration of electrolysis, the deposits consist of FeB or Fe2B. Microhardness measurements across the boride layer indicated very high hardness values (between 1600 and 2100 HV0.05. The structure of the boride layer is linked to its boron content and thermal history: as-deposited coatings present very small grain sizes and can be considered as nearly amorphous.

  18. Boron-dependency of molybdenum boride electrocatalysts for the hydrogen evolution reaction

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyounmyung; Encinas, Andrew; Fokwa, Boniface P.T. [Department of Chemistry, University of California, Riverside, CA (United States); Department of Chemical and Environmental Engineering, University of California, Riverside, CA (United States); Scheifers, Jan P.; Zhang, Yuemei [Department of Chemistry, University of California, Riverside, CA (United States)

    2017-05-08

    Molybdenum-based materials have been considered as alternative catalysts to noble metals, such as platinum, for the hydrogen evolution reaction (HER). We have synthesized four binary bulk molybdenum borides Mo{sub 2}B, α-MoB, β-MoB, and MoB{sub 2} by arc-melting. All four phases were tested for their electrocatalytic activity (linear sweep voltammetry) and stability (cyclic voltammetry) with respect to the HER in acidic conditions. Three of these phases were studied for their HER activity and by X-ray photoelectron spectroscopy (XPS) for the first time; MoB{sub 2} and β-MoB show excellent activity in the same range as the recently reported α-MoB and β-Mo{sub 2}C phases, while the molybdenum richest phase Mo{sub 2}B show significantly lower HER activity, indicating a strong boron-dependency of these borides for the HER. In addition, MoB{sub 2} and β-MoB show long-term cycle stability in acidic solution. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Boron-Dependency of Molybdenum Boride Electrocatalysts for the Hydrogen Evolution Reaction.

    Science.gov (United States)

    Park, Hyounmyung; Encinas, Andrew; Scheifers, Jan P; Zhang, Yuemei; Fokwa, Boniface P T

    2017-05-08

    Molybdenum-based materials have been considered as alternative catalysts to noble metals, such as platinum, for the hydrogen evolution reaction (HER). We have synthesized four binary bulk molybdenum borides Mo2 B, α-MoB, β-MoB, and MoB2 by arc-melting. All four phases were tested for their electrocatalytic activity (linear sweep voltammetry) and stability (cyclic voltammetry) with respect to the HER in acidic conditions. Three of these phases were studied for their HER activity and by X-ray photoelectron spectroscopy (XPS) for the first time; MoB2 and β-MoB show excellent activity in the same range as the recently reported α-MoB and β-Mo2 C phases, while the molybdenum richest phase Mo2 B show significantly lower HER activity, indicating a strong boron-dependency of these borides for the HER. In addition, MoB2 and β-MoB show long-term cycle stability in acidic solution. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Phase Evolution in Boride-Based Cermets and Reaction Bonding onto Plain Low Carbon Steel Substrate

    Science.gov (United States)

    Palanisamy, B.; Upadhyaya, A.

    2012-04-01

    Reaction sinter bonding is a process that aims to bond two materials for improvement in properties through reactive sintering technique. The process has been effectively used to sinter hard materials like borides in situ which not only possess excellent oxidation resistance, good corrosion resistance but also resistant to abrasive wear. Sinter bonding is a unique surface modification process achieved through powder metallurgy and is competent with other techniques like boronizing sintering and sinter-brazing since it eliminates the additional operations of heat treatment and assembly and removes the inherent setbacks with these processes. This study focuses on identifying the phase evolution mechanism using characterization tools like x-ray diffractometry and energy dispersive spectroscopy and study of sinter bonding of the boron containing precursors (Mo-Cr-Fe-Ni-FeB-MoB) onto plain carbon steel. A microstructure containing Fe-based matrix dispersed with complex borides develops with temperature in the tape cast sheets. A fivefold increase in hardness between plain carbon steel in wrought condition and sinter bonded steel was observed. The multilayer consisted of a reaction zone adjacent to the interface and was investigated with the composition profile and hardness measurements. A model of sinter bonding between the cermet and the steel has also been proposed.

  1. Chemical bond in borides. Theoretical and experimental analysis; Chemische Bindung in Boriden. Theoretische und experimentelle Untersuchung

    Energy Technology Data Exchange (ETDEWEB)

    Sagawe, Vanessa

    2013-04-18

    The aim of this work was the analysis of the bonding situation in different borides by examining the electron density in these structures. The main focus of the analysis was on the QTAIM analysis and the evaluation of the Electron Localizability Indicator (ELI-D). For the calculation of the electron density different methods (extended Hueckel, LMTO, (L)APW) were used to prove which method leads to most precise results. The (L)APW-method was found to be the most exact one and the one with the longest computational times. The examined compounds were boron-rich Borides containing icosahedra, Transition Metal Borides and Na{sub 3}B{sub 20}. Most of the structures of the examined boron-rich Borides can be derived directly from the MgB{sub 7} structure type (MgB{sub 7}, MgB{sub 12}C{sub 2}, LiB{sub 13}C{sub 2}, Li{sub 2}B{sub 12}C{sub 2}, LiB{sub 12}PC). The influence of the different cations as well as the interstitial atoms could be analyzed by comparing these compounds. Structures which can be derived from the alpha-rhombohedral Boron were also analyzed (B{sub 12}O{sub 2}, B{sub 12}P{sub 2}, B{sub 12}As{sub 2}). Assuming Bader-Charges the icosahedron is always positively charged if the electronegativity of the interstitial atoms is higher than the electronegativity of the Boron atoms. If their electronegativitiy is lower, the icosahedra are negatively charged. From the ELI-D-basins the bonding situation can be analyzed according to Wade by bisecting the basins of the exohedral bonds. The icosahedra are always negatively charged. However, Wade's rule is never exactly fulfilled as the charge is never exactly -2. To verify the results from theoretical calculations and vice versa, experimental electron density analyses of MgB{sub 7} and Li{sub 2}B{sub 12}C{sub 2} were performed. However, only the examination of MgB{sub 7} gave reliable results. They promoted the results by the calculations and underlined the correctness of the used methods. Results received by single

  2. Wear resistance of laser-deposited boride reinforced Ti-Nb-Zr-Ta alloy composites for orthopedic implants

    Energy Technology Data Exchange (ETDEWEB)

    Samuel, Sonia [Department of Materials Science and Engineering University of North Texas, Denton, TX (United States); Nag, Soumya [Department of Materials Science and Engineering Ohio State University, Columbus, OH (United States); Scharf, Thomas W.; Banerjee, Rajarshi [Department of Materials Science and Engineering University of North Texas, Denton, TX (United States)

    2008-04-01

    The inherently poor wear resistance of titanium alloys limits their application as femoral heads in femoral (hip) implants. Reinforcing the soft matrix of titanium alloys (including new generation {beta}-Ti alloys) with hard ceramic precipitates such as borides offers the possibility of substantially enhancing the wear resistance of these composites. The present study discusses the microstructure and wear resistance of laser-deposited boride reinforced composites based on Ti-Nb-Zr-Ta alloys. These composites have been deposited using the LENS{sup TM} process from a blend of elemental Ti, Nb, Zr, Ta, and boron powders and consist of complex borides dispersed in a matrix of {beta}-Ti. The wear resistance of these composites has been compared with that of Ti-6Al-4V ELI, the current material of choice for orthopedic femoral implants, against two types of counterfaces, hard Si{sub 3}N{sub 4} and softer SS440C stainless steel. Results suggest a substantial improvement in the wear resistance of the boride reinforced Ti-Nb-Zr-Ta alloys as compared with Ti-6Al-4V ELI against the softer counterface of SS440. The presence of an oxide layer on the surface of these alloys and composites also appears to have a substantial effect in terms of enhanced wear resistance.

  3. Simulation of the growth kinetics of the (FeB/Fe 2B) bilayer obtained on a borided stainless steel

    Science.gov (United States)

    Keddam, M.

    2011-01-01

    The present work is an attempt to simulate the growth kinetics of the (FeB/Fe 2B) bilayer grown on a substrate made of AISI 316 stainless steel by the application of the powder-pack boriding process, and using four different temperatures (1123, 1173, 1223 and 1273 K) and five exposure times (2, 4, 6, 8 and 10 h). The adopted diffusion model solves the mass balance equation at each growth front: (FeB/Fe 2B or FeB/substrate) under certain assumptions and without considering the diffusion zone. To consider the effect of the incubation times for the borides formation, the temperature-dependent function ϕ( T) was incorporated in the model. To validate this model, a computer code written in Matlab (version 6.5), was developed with the purpose of simulating the kinetics of the boride layers. This computer code uses the following parameters as input data: (the boriding temperature, the treatment time, the upper and lower limits of boron concentration in each iron boride, the diffusion coefficients of boron in the FeB and Fe 2B phases as well as the ϕ( T) parameter). The outputs of the computer code are the parabolic growth constant at each growth front and the thicknesses of the FeB and Fe 2B layers. A good agreement was obtained between the experimental parabolic growth constants taken from a reference work [I. Campos-Silva et al., Formation and kinetics of FeB/Fe 2B layers and diffusion zone at the surface of AISI 316 borided steels, Surf. Coat Technol., 205 (2010) 403-412] and the simulated values of the parabolic growth constants ( kFeB and k1). The present model was also able to predict the thicknesses of the FeB and Fe 2B layers at a temperature of 1243 K during 3 and 5 h. In addition, the mass gain at the material surface was also estimated as a function of the time and the upper boron content in each iron boride phase. It was shown that the simulated values of the generated mass gain are very sensitive to the increase of both temperature and the upper boron

  4. Ekstraksi Pemisahan Neodimium dari Samarium, Itrium dan Praseodimium Memakai Tri Butil Fosfat

    Directory of Open Access Journals (Sweden)

    Maria Veronica Purwani

    2017-05-01

    Full Text Available The extraction of Nd(OH3 (neodymium hydroxide concentrate containing Y (yttrium, Sm (samarium and Pr (praseodymium as product of monazite processed has been done. The purpose of this study is to determine the separation of Nd from Y, Pr and Nd Sm in Nd concentrate. The aqueous phase was concentrated Nd (OH3 in HNO3 and extractant while organic phase was Tri Butyl Phosphate (TBP in kerosene. Parameters studied were pH and concentration feed, concentration of TBP in kerosene, extraction time and stirring speed. The result showed that the optimization of separation extraction neodymium from samarium, yttrium and praseodymium in Nd(OH3 concentrated with TBP, obtained the optimum condition of pH = 0.2, concentration of feed 100 g /L, concentration of TBP in kerosene 5%, extraction time 15 minutes and stirring speed 150 rpm. With the conditions, Separation Factor (SF obtained for Nd-Y, Nd-Pr, Nd-Sm are 2.242, 4.811, 4.002 respectively, while D and extraction efficiency of Nd are 0.236 and 19.07%.

  5. X-Band Microwave Reflection Properties of Samarium/Bismuth-Substituted Barium Lanthanum Titanate Ceramics

    Science.gov (United States)

    Bahel, Shalini; Pubby, Kunal; Narang, Sukhleen Bindra

    2017-03-01

    Samarium/bismuth-substituted barium lanthanum titanate ceramics with chemical composition Ba4 (La_{1 - y - z} Smy Biz )_{9.33} Ti_{18} O_{54} ( y = 0.5, 0.7; z = 0.05, 0.10, 0.15), intended as microwave reflecting materials, have been investigated in microwave X-band (8.2 GHz to 12.4 GHz) and the effect of substitution on their dielectric properties, i.e., dielectric constant and dielectric loss tangent, has been studied by vector network analyzer. Dielectric analysis showed that the dielectric constant increased with increasing samarium as well as bismuth content. Dielectric relaxation was observed for all samples in the scanned frequency range. Microwave reflection and transmission analysis of ceramic pellets of thickness 4 mm was carried out using two methods, i.e., open- and short-circuit approach, both indicating very high values of reflected power and very low values of transmitted power for all the doped materials in comparison with the base composition. The doped compositions are therefore potential microwave shielding materials for use in anechoic chambers, microwave laboratories, and radar equipment. Double-layer reflectors are also proposed, having better reflection properties (˜99% reflection) compared with single-layer reflectors.

  6. Microstructure and hysteresis curves of samarium-holmium-iron garnet synthesized by coprecipitation

    Directory of Open Access Journals (Sweden)

    Caffarena Valeska da Rocha

    2003-01-01

    Full Text Available An investigation was made into the synthesis and magnetic properties of Sm(3-xHo xFe5O12 (samarium-holmium-iron garnet ferrite, as yet absent from the literature. The material in question was synthesized by co-precipitation, starting from hydrated chlorides of rare-earth elements and ferrous sulfate, and the mixed hydroxide co-precipitate was calcined at 1000 °C. Using PVA as a binder, rectangular cross section-shaped compacts were produced by means of steel-die pressing, drying and sintering from 1200 to 1450 °C. The main conclusions of this study were that the coercive force decreases as the sintering temperature increases, and that the effect of substituting holmium for samarium in SmIG is entirely different from that provided by replacing yttrium by gadolinium in YIG, which is the most important result of this work. An in-depth investigation will be necessary to determine the correlation between microstructure/magnetic properties and ceramic processing variables.

  7. Bone-seeking radiopharmaceuticals as targeted agents of osteosarcoma: samarium-153-EDTMP and radium-223.

    Science.gov (United States)

    Anderson, Peter M; Subbiah, Vivek; Rohren, Eric

    2014-01-01

    Osteosarcoma is a cancer characterized by formation of bone by malignant cells. Routine bone scan imaging with Tc-99m-MDP is done at diagnosis to evaluate primary tumor uptake and check for bone metastases. At time of relapse the Tc-99m-MDP bone scan also provides a specific means to assess formation of bone by malignant osteosarcoma cells and the potential for bone-seeking radiopharmaceuticals to deliver radioactivity directly into osteoblastic osteosarcoma lesions. This chapter will review and compare a bone-seeking radiopharmaceutical that emits beta-particles, samarium-153-EDTMP, with an alpha-particle emitter, radium-223. The charged alpha particles from radium-223 have far more mass and energy than beta particles (electrons) from Sm-153-EDTMP. Because radium-223 has less marrow toxicity and more radiobiological effectiveness, especially if inside the bone forming cancer cell than samarium-153-EDTMP, radium-223 may have greater potential to become widely used against osteosarcoma as a targeted therapy. Radium-223 also has more potential to be used with chemotherapy against osteosarcoma and bone metastases. Because osteosarcoma makes bone and radium-223 acts like calcium, this radiopharmaceutical could possibly become a new targeted means to achieve safe and effective reduction of tumor burden as well as facilitate better surgery and/or radiotherapy for difficult to resect large, or metastatic tumors.

  8. Polypyrrole-coated samarium oxide nanobelts: fabrication, characterization, and application in supercapacitors

    Science.gov (United States)

    Liu, Peng; Wang, Yunjiao; Wang, Xue; Yang, Chao; Yi, Yanfeng

    2012-11-01

    Polypyrrole-coated samarium oxide nanobelts were synthesized by the in situ chemical oxidative surface polymerization technique based on the self-assembly of pyrrole on the surface of the amine-functionalized Sm2O3 nanobelts. The morphologies of the polypyrrole/samarium oxide (PPy/Sm2O3) nanocomposites were characterized using transmission electron microscope. The UV-vis absorbance of these samples was also investigated, and the remarkable enhancement was clearly observed. The electrochemical behaviors of the PPy/Sm2O3 composites were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge. The results indicated that the PPy/Sm2O3 composite electrode was fully reversible and achieved a very fast Faradaic reaction. After being corrected into the weight percentage of the PPy/Sm2O3 composite at a current density of 20 mA cm-2 in a 1.0 M NaNO3 electrolyte solution, a maximum discharge capacity of 771 F g-1 was achieved in a half-cell setup configuration for the PPy/Sm2O3 composites electrode with the potential application to electrode materials for electrochemical capacitors.

  9. Polypyrrole-coated samarium oxide nanobelts: fabrication, characterization, and application in supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu Peng, E-mail: pliu@lzu.edu.cn; Wang Yunjiao; Wang Xue; Yang Chao; Yi Yanfeng [College of Chemistry and Chemical Engineering, Lanzhou University, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province and State Key Laboratory of Applied Organic Chemistry (China)

    2012-11-15

    Polypyrrole-coated samarium oxide nanobelts were synthesized by the in situ chemical oxidative surface polymerization technique based on the self-assembly of pyrrole on the surface of the amine-functionalized Sm{sub 2}O{sub 3} nanobelts. The morphologies of the polypyrrole/samarium oxide (PPy/Sm{sub 2}O{sub 3}) nanocomposites were characterized using transmission electron microscope. The UV-vis absorbance of these samples was also investigated, and the remarkable enhancement was clearly observed. The electrochemical behaviors of the PPy/Sm{sub 2}O{sub 3} composites were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge. The results indicated that the PPy/Sm{sub 2}O{sub 3} composite electrode was fully reversible and achieved a very fast Faradaic reaction. After being corrected into the weight percentage of the PPy/Sm{sub 2}O{sub 3} composite at a current density of 20 mA cm{sup -2} in a 1.0 M NaNO{sub 3} electrolyte solution, a maximum discharge capacity of 771 F g{sup -1} was achieved in a half-cell setup configuration for the PPy/Sm{sub 2}O{sub 3} composites electrode with the potential application to electrode materials for electrochemical capacitors.

  10. Behavior of Samarium III during the sorption process; Comportamiento del Samario-III durante el proceso de sorcion

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Garcia G, N.; Garcia R, G. [ININ, Carr. Mexico-Toluca Km 36.5, Salazar, Estado de Mexico (Mexico)]. e-mail: edo@nuclear.inin.mx

    2004-07-01

    In this work the results of the behavior of samarium in solution are presented, in front of a fine powder of zirconium silicate (zircon). For that which is necessary to characterize the zircon, studying the crystallinity, the morphology, the surface area and the isoelectric point. The behavior of samarium in solution is studied by means of the elaboration of isotherm of sorption, using the technique by lots. One observes that to pH values of nearer to the isoelectric point (pH = 7.23) the process of sorption of the samarium begins, reaching a maximum to near pH at 9. The technique of luminescence is used to determine the concentration of the sipped samarium (phosphorescence) and also to make the speciation of the species formed in the surface of the zircon (phosphorescence). The results can be extrapolated with the plutonium when making the modeling of the migration of alpha emitting coming from the repositories of radioactive waste since both they have similar chemical properties (they are homologous). (Author)

  11. Neutron and Charged-Particle Induced Cross Sections for Radiochemistry in the Region of Samarium, Europium, and Gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, R D; Kelley, K; Dietrich, F S; Bauer, R; Mustafa, M

    2004-11-30

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron and proton induced nuclear reaction cross sections in the mass region of samarium, europium and gadolinium (62 {le} Z {le} 64, 82 {le} N {le} 96).

  12. Pemisahan Unsur Samarium dan Yttrium dari Mineral Tanah Jarang dengan Teknik Membran Cair Berpendukung (Supported Liquid Membrane

    Directory of Open Access Journals (Sweden)

    Amri Amin

    2009-06-01

    Full Text Available he increasing use of rare earth elements in high technology industries needs to be supported by developmental work for the separation of elements. The research objective is fiercely attracting and challenging considering the similarity of bath physical and chemical properties among these elements. The rate separation of samarium and yttrium elements using supported liquid membrane has been studied. Polytetrafluoroethylene (PTFE with pore size of 0.45 µm has been used as the membrane and di(2-ethylhexyl phosphate (D2EHP in hexane has been used as a carrier and nitric acid solution has been used as receiving phase. Result of experiments showed that the best separation rate of samarium and yttrium elements could be obtained at feeding phase of pH 3.0, di(2-ethylhexyl phosphate (D2EHP concentration of 0.3 M, agitation rate of 700 rpm, agitation time of 2 hours, and nitric acid and its solution concentrations of 1.0 M and 0.1 M, respectively. At this condition, separation rates of samarium and yttrium were 64.4 and 67.6%, respectively.   Keywords: liquid membrane, rare earth elements, samarium, yttrium

  13. High Temperature Sliding Wear of NiAl-based Coatings Reinforced by Borides

    Directory of Open Access Journals (Sweden)

    Oleksandr UMANSKYI

    2016-05-01

    Full Text Available The development of composite materials (CM in the systems “metal-refractory compound” is one of the up-to-date trends in design of novel materials aimed at operating under the conditions of significant loads at high temperature. To design such material, NiAl, which is widely used for deposition of protective coatings on parts of gas-turbine engines, was selected for a matrix. To strengthen a NiAl under the conditions of intense wear and a broad temperature range (up to 1000 °C, it is reasonable to add refractory inclusions. Introduction of refractory borides into matrix leads to a marked increase in metal wear resistance. In order to research the behavior of the designed composites at high temperatures and to study the influence of oxides on the friction processes, the authors carried out high temperature oxidation of CM of the above systems at 1000 °С for 90 min. It was determined that all of the composites were oxidized selectively and that the thickness of oxide layers formed on the boride inclusions is 3 – 7 times that on the oxides formed on the NiAl matrix. The mechanism of wear of gas-thermal coatings of the NiAl – МеB2 systems was studied for conditions of high temperature tribotests using the «pin-on-disc» technique. The obtained results indicate that introduction of TiB2, CrB2 and ZrB2 leads to their more intense oxidation during high temperature tribotests as compared to the matrix. The oxides formed on refractory borides act as solid lubricants, which promote a decrease in wear of the contact friction pairs. For more detailed investigation of the effect of tribo-oxidation products on the friction processes, tribotests were conducted for prior oxidized (at 900 °С coatings NiAl – 15 wt.% CrB2 (TiB2, ZrB2.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.8093

  14. Superconductivity in the metal rich Li-Pd-B ternary boride.

    Science.gov (United States)

    Togano, K; Badica, P; Nakamori, Y; Orimo, S; Takeya, H; Hirata, K

    2004-12-10

    Superconductivity at about 8 K was observed in the metal-rich Li-Pd-B ternary system. Structural, microstructural, electrical, and magnetic investigations for various compositions proved that the Li2Pd3B compound, which has an antiperovskite cubic structure composed of distorted Pd6B octahedrons, is responsible for the superconductivity. This is the first observation of superconductivity in metal-rich ternary borides containing alkaline metal and Pd as a late transition metal. The compound prepared by arc melting has a high density and is relatively stable in the air. The upper critical fields H(c2)(0) estimated by linear extrapolation and the Werthamer-Helfand-Hohenberg theory are 6.2 and 4.8 T, respectively.

  15. Toxicogenomic responses of human alveolar epithelial cells to tungsten boride nanoparticles.

    Science.gov (United States)

    Türkez, Hasan; Arslan, Mehmet Enes; Sönmez, Erdal; Tatar, Abdulgani; Açikyildiz, Metin; Geyikoğlu, Fatime

    2017-08-01

    During the recent years, microarray analysis of gene expression has become an inevitable tool for exploring toxicity of drugs and other chemicals on biological systems. Therefore, toxicogenomics is considered as a fruitful area for searching cellular pathways and mechanisms including cancer, immunological diseases, environmental responses, gene-gene interactions and chemical toxicity. In this work, we examined toxic effects of Tungsten Borides NPs on gene expression profiling of the human lung alveolar epithelial cells (HPAEpiC). In line with this purpose, a single crystal of tungsten boride (mixture of WB and W2B) nanoparticles was synthesized by means of zone melting method, and characterized via using X-ray crystallography (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) techniques. Cell viability and cytotoxicity were determined by 3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT), neutral red (NR) and lactate dehydrogenase (LDH) release tests. The whole genome microarray expression analysis was performed to find out the effects of WB and W2B NPs mixture on gene expression of the HPAEpiC cell culture. 123 of 40,000 gene probes were assigned to characterize expression profile for WB/W2B NPs exposure. According to results; 70 genes were up-regulated and 53 genes were down-regulated (≥2 fold change). For further investigations, these genes were functionally classified by using DAVID (The Database for Annotation, Visualization and Integrated Discovery) with gene ontology (GO) analysis. In the light of the data gained from this study, it could be concluded that the mixture of WB/W2B NPs can affect cytokine/chemokine metabolism, angiogenesis and prevent migration/invasion by activating various genes. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Effects of the atomic environment on the electron binding energies in samarium

    Energy Technology Data Exchange (ETDEWEB)

    Inoyatov, A.Kh., E-mail: inoyatov@jinr.ru [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Institute of Applied Physics, National University, Tashkent, Republic of Uzbekistan (Uzbekistan); Kovalík, A. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Nuclear Physics Institute of the ASCR, CZ-25068 Řež near Prague (Czech Republic); Filosofov, D.V. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Ryšavý, M.; Vénos, D. [Nuclear Physics Institute of the ASCR, CZ-25068 Řež near Prague (Czech Republic); Yushkevich, Yu.V.; Perevoshchikov, L.L. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Zhdanov, V.S. [Nuclear Physics Institute, Almaty, Republic of Kazakhstan (Kazakhstan)

    2016-02-15

    Highlights: • Eight different matrices (evaporated and implanted at 30 keV) used. • The greatest average difference in the binding energies amounted to 3.1 ± 0.1 eV. • The presence of trivalent and divalent Sm ions found in some implanted samples. • No significant differences in Sm natural atomic level widths were observed. - Abstract: Effects of the atomic environment on the L{sub 1}, L{sub 2}, L{sub 3}, M{sub 1}, M{sub 2}, M{sub 3}, and N{sub 1} electron binding energies in samarium generated in the electron capture decay of radioactive {sup 149}Eu were investigated by means of the internal conversion electron spectroscopy using the conversion electron spectrum of the 22.5 keV M1 + E2 nuclear transition in the daughter {sup 149}Sm. In this investigation, four pairs of {sup 149}Eu sources prepared by vacuum evaporation deposition and by ion implantation at 30 keV with the use of four different source backing materials, namely polycrystalline carbon, aluminium, gadolinium and platinum foils, were employed. The greatest average difference of (3.1 ± 0.1) eV in the L{sub 1}, L{sub 2}, L{sub 3}, and M{sub 1} subshell electron binding energies was observed between the {sup 149}Eu sources prepared by ion implantation into the aluminium and platinum substrates. On the other hand, minimal differences in the electron binding energies were generally found between samarium generated in the evaporated layer and in the bulk for the individual investigated source backings with the exception of the gadolinium foil. A doublet structure of all investigated conversion electron lines with the average values of 8.1 ± 0.2 eV and 1.5 ± 0.1 for the separation energy and the intensity ratio of the low-energy to high-energy components, respectively, was observed for the {sup 149}Eu sources prepared by ion implantation into the aluminium and carbon foils. This structure was presumably caused by the presence of both the trivalent and divalent Sm ions in the sources. No

  17. PREFACE: The 16th International Symposium on Boron, Borides and Related Materials (ISBB 2008)

    Science.gov (United States)

    Tanaka, Takaho

    2009-07-01

    This volume of Journal of Physics: Conference Series contains invited and contributed peer-reviewed papers that were presented at the 16th International Symposium on Boron, Borides and Related Materials (ISBB 2008), which was held on 7-12 September 2008, at Kunibiki Messe, Matsue, Japan. This triennial symposium has a half-century long history starting from the 1st meeting in 1959 at Asbury Park, New Jersey. We were very pleased to organize ISBB 2008, which gathered chemists, physicists, materials scientists as well as diamond and high-pressure researchers. This meeting had a strong background in the boron-related Japanese research history, which includes the discovery of superconductivity in MgB2 and development of Nd-Fe-B hard magnets and of YB66 soft X-ray monochromator. The scope of ISBB 2008 spans both basic and applied interdisciplinary research that is centered on boron, borides and related materials, and the collection of articles defines the state of the art in research on these materials. The topics are centered on: 1. Preparation of new materials (single crystals, thin films, nanostructures, ceramics, etc) under normal or extreme conditions. 2. Crystal structure and chemical bonding (new crystal structures, nonstoichiometry, defects, clusters, quantum-chemical calculations). 3. Physical and chemical properties (band structure, phonon spectra, superconductivity; optical, electrical, magnetic, emissive, mechanical properties; phase diagrams, thermodynamics, catalytic activity, etc) in a wide range of temperatures and pressures. 4. Applications and prospects (thermoelectric converters, composites, ceramics, coatings, etc) There were a few discoveries of new materials, such as nanomaterials, and developments in applications. Many contributions were related to 4f heavy Fermion systems of rare-earth borides. Exotic mechanisms of magnetism and Kondo effects have been discussed, which may indicate another direction of development of boride. Two special sessions

  18. Interlayer utilization (including metal borides) for subsequent deposition of NSD films via microwave plasma CVD on 316 and 440C stainless steels

    Science.gov (United States)

    Ballinger, Jared

    Diamond thin films have promising applications in numerous fields due to the extreme properties of diamonds in conjunction with the surface enhancement of thin films. Biomedical applications are numerous including temporary implants and various dental and surgical instruments. The unique combination of properties offered by nanostructured diamond films that make it such an attractive surface coating include extreme hardness, low obtainable surface roughness, excellent thermal conductivity, and chemical inertness. Regrettably, numerous problems exist when attempting to coat stainless steel with diamond generating a readily delaminated film: outward diffusion of iron to the surface, inward diffusion of carbon limiting necessary surface carbon precursor, and the mismatch between the coefficients of thermal expansion yielding substantial residual stress. While some exotic methods have been attempted to overcome these hindrances, the most common approach is the use of an intermediate layer between the stainless steel substrate and the diamond thin film. In this research, both 316 stainless steel disks and 440C stainless steel ball bearings were tested with interlayers including discrete coatings and graded, diffusion-based surface enhancements. Titanium nitride and thermochemical diffusion boride interlayers were both examined for their effectiveness at allowing for the growth of continuous and adherent diamond films. Titanium nitride interlayers were deposited by cathodic arc vacuum deposition on 440C bearings. Lower temperature diamond processing resulted in improved surface coverage after cooling, but ultimately, both continuity and adhesion of the nanostructured diamond films were unacceptable. The ability to grow quality diamond films on TiN interlayers is in agreement with previous work on iron and low alloy steel substrates, and the similarly seen inadequate adhesion strength is partially a consequence of the lacking establishment of an interfacial carbide phase

  19. Multiphoton laser wave-mixing absorption spectroscopy for samarium using a graphite furnace atomizer

    Energy Technology Data Exchange (ETDEWEB)

    Maniaci, Michael J.; Tong, William G. E-mail: william.tong@sdsu.edu

    2004-07-30

    Nonlinear laser wave-mixing optical technique is presented as a sensitive atomic spectroscopic method for the analysis of rare earth elements using an unmodified commercially available graphite furnace (GF) atomizer. A simple nonplanar backward-scattering degenerate four-wave mixing optical arrangement offers sub-picogram detection sensitivity with sub-Doppler Lorentzian-broadened resolution. Nonlinear wave mixing is an unusually sensitive absorption-based optical method that offers both excellent detection sensitivity and sub-Doppler spectral resolution. A mass detection limit of 0.7 pg and a concentration detection limit of 70 pg/ml are determined for a rare earth element, samarium, using the 429.7-nm excitation line.

  20. Samarium Doped Cerium Oxide Clusters: a Study on the Modulation of Electronic Structure

    Science.gov (United States)

    Topolski, Josey E.; Kafader, Jared O.; Marrero-Colon, Vicmarie; Chick Jarrold, Caroline

    2017-06-01

    Cerium oxide is known for its use in solid oxide fuel cells due to its high ionic conductivity. The doping of trivalent samarium atoms into cerium oxide is known to enhance the ionic conductivity through the generation of additional oxygen vacancies. This study probes the electronic structure of Sm_{x}Ce_{y}O_{z} (x+y=3, z=2-4) anion and neutral clusters. Anion photoelectron spectra of these mixed metal clusters exhibit additional spectral features not present in the previously studied cerium oxide clusters. Density functional theory calculations have been used to aid interpretation of collected spectra. The results of this work can be used to inform the design of materials used for solid oxide fuel cells.

  1. Chelating Ligand-Mediated Hydrothermal Synthesis of Samarium Orthovanadate with Decavanadate as Vanadium Source

    Directory of Open Access Journals (Sweden)

    Quanguo Li

    2013-01-01

    Full Text Available A new ethylenediaminetetraacetic acid- (EDTA- mediated hydrothermal route to prepare chrysanthemum-shaped samarium orthovanadate (SmVO4 nanocrystals with decavanadate (K6V10O28·9H2O as vanadium source has been developed. The present hydrothermal approach is simple and reproducible and employs a relatively mild reaction temperature. The EDTA, pH value, and temperature of the reaction systems play important roles in determining the morphologies and growth process of the SmVO4 products. The products have been characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FT-IR, photoluminescence spectra (PL, and UV-Vis spectroscopy.

  2. The Magnetocaloric Effect and Heat Capacity of Suspensions of High-Dispersity Samarium Ferrite

    Science.gov (United States)

    Korolev, V. V.; Aref'ev, I. M.; Ramazanova, A. G.

    2008-02-01

    The magnetocaloric effect and specific heat capacity of an aqueous suspension of samarium ferrite were determined calorimetrically over the temperature range 288-343 K in magnetic fields of 0-0.7 T. The data obtained were used to calculate changes in the magnetic component of the molar heat capacity and entropy of the magnetic phase and changes in the enthalpy of the process under an applied magnetic field. The magnetocaloric effect was found to increase nonlinearly as the magnetic field induction grew. The corresponding temperature dependences contained a maximum at 313 K related to the second-order magnetic phase transition at the Curie point. The field and temperature dependences of heat capacity contained a maximum in fields of 0.4 T and a minimum at the magnetic phase transition temperature.

  3. Preparation of hollow core/shell microspheres of hematite and its adsorption ability for samarium.

    Science.gov (United States)

    Yu, Sheng-Hui; Yao, Qi-Zhi; Zhou, Gen-Tao; Fu, Sheng-Quan

    2014-07-09

    Hollow core/shell hematite microspheres with diameter of ca. 1-2 μm have been successfully achieved by calcining the precursor composite microspheres of pyrite and polyvinylpyrrolidone (PVP) in air. The synthesized products were characterized by a wide range of techniques including powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and Brunauer-Emmett-Teller (BET) gas sorptometry. Temperature- and time-dependent experiments unveil that the precursor pyrite-PVP composite microspheres finally transform into hollow core/shell hematite microspheres in air through a multistep process including the oxidation and sulfation of pyrite, combustion of PVP occluded in the precursor, desulfation, aggregation, and fusion of nanosized hematite as well as mass transportation from the interior to the exterior of the microspheres. The formation of the hollow core/shell microspheres dominantly depends on the calcination temperature under current experimental conditions, and the aggregation of hematite nanocrystals and the core shrinking during the oxidation of pyrite are responsible for the formation of the hollow structures. Moreover, the adsorption ability of the hematite for Sm(III) was also tested. The results exhibit that the hematite microspheres have good adsorption activity for trivalent samarium, and that its adsorption capacity strongly depends on the pH of the solution, and the maximum adsorption capacity for Sm(III) is 14.48 mg/g at neutral pH. As samarium is a typical member of the lanthanide series, our results suggest that the hollow hematite microspheres have potential application in removal of rare earth elements (REEs) entering the water environment.

  4. The influence of the technological parameters on the ionic conductivity of samarium doped ceria thin films

    Directory of Open Access Journals (Sweden)

    Mantas Sriubas

    2015-03-01

    Full Text Available Sm0,20Ce0,80O2 powder was used for the formation of samarium doped cerium oxide (SDC thin films using e-beam. Surface area of powder was 34.9 m2/g and particle size – 0.3-0.5 μm. Thin films were deposited using physical vapor deposition system on SiO2 and Alloy 600 substrates. 2 Å/s – 16 Å/s growth rate and 20 °C – 600 °C substrate temperature were used during the deposition. Ionic conductivity investigation revealed that the maximum ionic conductivity (1.67 S/m has the thin film deposited on 300 °C temperature substrate using 4 Å/s growth rate. Minimum ionic conductivity (0.26 S/m has thin film which was deposited on 20 °C temperature substrate using 8 Å/s growth rate. Vacancy activation energies vary in 0.87 eV – 0.97 eV range. Furthermore the calculations of crystallite size revealed that crystallite size increases with increasing substrate temperature: from 7.50 nm to 46.23 nm on SiO2 substrate and from 9.30 nm to 44.62 nm on Alloy 600 substrate. Molar concentration of samarium in initial evaporated material is 19.38 mol% and varies from 11.37 mol% to 21 mol% in formed thin films depending on technological parameters.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5700

  5. Corrosion Resistance of Nanopowders of Borides and Carbides of IV-VIB Group Metals in the Nickeling Electrolytes.

    Science.gov (United States)

    Shakhnin, Dmytro; Malyshev, Viktor; Kuschevskaya, Nina; Gab, Angelina

    2017-12-01

    The corrosion resistance of nanopowders of borides and carbides of metals of IV-VIB groups, as well as of silicon carbide, was studied in the standard nickeling electrolytes. As objects of study, nanopowders with the content of the main phase 91.8-97.6% and with the average particle size 32-78 nm were used. Their corrosion resistance was evaluated depending on the acidity of the electrolyte, temperature, and duration of the interaction. It was found that, by the corrosion resistance in the electrolytes solutions, nanopowders of borides and carbides within each group of compounds are similar and characterized by unlimited period of induction in alkaline media. An exception is the nanopowder of silicon carbide which is resistant to the solution of any acidity.

  6. Chemical modeling of mixed occupations and site preferences in anisotropic crystal structures: case of complex intermetallic borides.

    Science.gov (United States)

    Deringer, Volker L; Goerens, Christian; Esters, Marco; Dronskowski, Richard; Fokwa, Boniface P T

    2012-05-21

    Transition-metal borides show not only promising physical properties but also a rich variety of crystal structures. In this context, quantum-chemical tools can shed light on important facets of the chemistry within such intermetallic borides. Using density-functional theory (DFT), we analyze in detail two phases of significant structural-chemical importance: the recently synthesized Ti(1+x)Os(2-x)RuB(2) and the isotypical Ti(1+x)Os(3-x)B(2). Starting from the observation of different Ti/Os occupations in X-ray crystal structure analysis, we assess suitable computational models and rationalize how the interplay of Ti-Ti, Ti-Os, and Os-Os bonds drives the site preferences. Then, we move on to a systematic investigation of the metal-boron bonds which embed the characteristic, trigonal-planar B(4) units within their metallic surroundings. Remarkably, the different Ti-B bonds in Ti(1+x)Os(2-x)RuB(2) (and also in its ternary derivative) are of vastly different strength, and the strength of these bonds does not correlate with their length. The tools presented in this work are based on simple and insightful chemical arguments together with DFT, and may subsequently be transferred to other intermetallic phases--transition-metal borides and beyond.

  7. Formation of Core-Shell Nanoparticles Composed of Magnetite and Samarium Oxide in Magnetospirillum magneticum Strain RSS-1.

    Science.gov (United States)

    Shimoshige, Hirokazu; Nakajima, Yoshikata; Kobayashi, Hideki; Yanagisawa, Keiichi; Nagaoka, Yutaka; Shimamura, Shigeru; Mizuki, Toru; Inoue, Akira; Maekawa, Toru

    2017-01-01

    Magnetotactic bacteria (MTB) synthesize magnetosomes composed of membrane-enveloped magnetite (Fe3O4) or greigite (Fe3S4) particles in the cells. Recently, several studies have shown some possibilities of controlling the biomineralization process and altering the magnetic properties of magnetosomes by adding some transition metals to the culture media under various environmental conditions. Here, we successfully grow Magnetospirillum magneticum strain RSS-1, which are isolated from a freshwater environment, and find that synthesis of magnetosomes are encouraged in RSS-1 in the presence of samarium and that each core magnetic crystal composed of magnetite is covered with a thin layer of samarium oxide (Sm2O3). The present results show some possibilities of magnetic recovery of transition metals and synthesis of some novel structures composed of magnetic particles and transition metals utilizing MTB.

  8. Co-reduction of aluminium and lanthanide ions in molten fluorides: Application to cerium and samarium extraction from nuclear wastes

    Energy Technology Data Exchange (ETDEWEB)

    Gibilaro, M. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite de Toulouse, 31062 Toulouse Cedex 9 (France); Massot, L. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite de Toulouse, 31062 Toulouse Cedex 9 (France)], E-mail: massot@chimie.ups-tlse.fr; Chamelot, P.; Taxil, P. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite de Toulouse, 31062 Toulouse Cedex 9 (France)

    2009-09-01

    This work concerns the method of co-reduction process with aluminium ions in LiF-CaF{sub 2} medium (79-21 mol.%) on tungsten electrode for cerium and samarium extraction. Electrochemical techniques such as cyclic and square wave voltammetries, and potentiostatic electrolyses were used to study the co-reduction of CeF{sub 3} and SmF{sub 3} with AlF{sub 3}. For each of these elements, specific peaks of Al-Ce and Al-Sm alloys formation were observed by voltammetry as well as peaks of pure cerium and aluminium, and pure samarium and aluminium respectively. The difference of potential measured between the solvent reduction and the alloy formation suggests expecting an extraction efficiency of 99.99% of each lanthanide by the process. Different intermetallic compounds were obtained for different potentiostatic electrolysis and were characterised by Scanning Electron Microscopy with EDS probe. The validity of the process was verified by carrying out cerium and samarium extractions in the form of Al-Ln alloy; the extraction efficiency was 99.5% for Ce(III) and 99.4% for Sm(III)

  9. The structure and hardness of the highest boride of tungsten, a borophene-based compound.

    Science.gov (United States)

    Gonzalez Szwacki, Nevill

    2017-06-22

    Two-dimensional systems have strengthened their position as a key materials for novel applications. Very recently, boron joined the distinguished group of elements confirmed to possess 2D allotropes, named borophenes. In this work, we explore the stability and hardness of the highest borides of tungsten, which are built of borophenes separated by metal atoms. We show that the WB3+x compounds have Vickers hardnesses approaching 40 GPa only for small values of x. The insertion of extra boron atoms is, in general, detrimental to the hardness of WB3 because it leads to the formation of quasi-planar boron sheets that are less tightly connected with the adjacent tungsten layers. Very high concentrations of boron (x ≈ 1), give rise to a soft (Vickers hardness of ~8 GPa) and unstable hP20-WB4 structure that can be considered to be built of quasi-planar boron α-sheets separated by graphitic tungsten layers. By contrast, we show that the formation of tungsten vacancies leads to structures, e.g. W0.75B3+x , with Vickers hardnesses that are not only similar in value to the experimentally reported load-independent hardnesses greater than 20 GPa, but are also less sensitive to variations in the boron content.

  10. Structural and luminescence properties of samarium doped lead alumino borate glasses

    Science.gov (United States)

    Mohan, Shaweta; Kaur, Simranpreet; Singh, D. P.; Kaur, Puneet

    2017-11-01

    The study reports the effect of samarium concentration on the physical, structural and spectroscopic characteristics of samarium doped lead alumino borate glasses having composition 20PbO-(10-x)Al2O3-70B2O3-xSm2O3; x = 0.1, 0.5, 1.0 and 2.0 mol %. The glasses were fabricated by conventional melt-quenching technique and then characterized by XRD, FTIR, optical absorption and fluorescence spectra. X-ray diffraction studies confirmed the amorphous nature of the prepared glasses. FTIR spectra indicate the presence of BO3, BO4, AlO6 and a few other structural groups. Various physical properties such as density, molar volume, refractive index, rare earth ion concentration, boron-boron distance and polarizability etc. were determined using conventional methods and standard formulae. The Judd-Ofelt theory was applied on the optical absorption spectra of the glasses to evaluate the three phenomenological intensity parameters Ω2, Ω4 and Ω6. The value of Ω2 was found to be highest for glass with 1 mol% Sm2O3 and attributed to the asymmetry of the ligand field at the rare earth ion site and the rare earth oxygen (Sm-O) covalency. The calculated intensity parameters and fluorescence spectra were further used to predict the radiative transition probability (A), radiative lifetime (τR), branching ratio (βR), peak wavelength (λp), effective line widths (Δλeff) and stimulated emission cross-section (σ) for the characteristic 4G5/2 → 6H5/2, 6H7/2 and 6H9/2 transitions of the Sm3+ ion. Concentration quenching was observed for 2 mol% concentration of Sm2O3 and ascribed to energy transfer through various cross-relaxation channels between Sm3+ ions. Reasonably high values of branching ratios and stimulated emission cross-section for the prepared glasses points towards their utility in the development of visible lasers emitting in the reddish-orange spectral region. However, the glass with 1 mol% Sm2O3 was found to show better radiative properties.

  11. X-ray Induced Luminescence Spectroscopy of Samarium Doped Barium Sulfate Prepared by Sintering Method

    Science.gov (United States)

    Kumeda, T.; Maeda, K.; Shirano, Y.; Fujiwara, K.; Sakai, K.; Ikari, T.

    2015-06-01

    X-ray induced luminescence (XL) properties of phosphor materials made of samarium doped barium sulfate have been investigated. The samples were prepared by sintering method heated at 900-1250 °C for 3 hours in air from the mixture of BaSO4 and Sm2O3. The concentration of Sm were prepared from 0.01-6 at.%. In as-prepared sample, the Sm3+ was detected by photoluminescence (PL). The PL intensity is maximum about 2 at.% with Sm, and then starts decreasing. The PL intensity showed concentration quenching. The XL observed Sm2+ and Sm3+ ions. The XL was shown from the sample sintered up to 1200 °C. The XL intensity increased with Sm concentration up to 1 at.%. The intensity was almost constant larger than 1 at.% Sm. These concentration dependences is different since the X-ray energy absorbed to the host material at once, and the energy transferred to both Sm3+ and Sm2+ ions. Sm doped BaSO4 is found a host for XL phosphor materials.

  12. High-κ Samarium-Based Metal-Organic Framework for Gate Dielectric Applications.

    Science.gov (United States)

    Pathak, Abhishek; Chiou, Guan Ru; Gade, Narsinga Rao; Usman, Muhammad; Mendiratta, Shruti; Luo, Tzuoo-Tsair; Tseng, Tien Wen; Chen, Jenq-Wei; Chen, Fu-Rong; Chen, Kuei-Hsien; Chen, Li-Chyong; Lu, Kuang-Lieh

    2017-07-05

    The self-assembly of a samarium-based metal-organic framework [Sm2(bhc)(H2O)6]n (1) in good yield was achieved by reacting Sm(NO3)3·6H2O with benzenehexacarboxylic acid (bhc) in a mixture of H2O-EtOH under hydrothermal conditions. A structural analysis showed that compound 1 crystallized in a space group of Pnmn and adopted a 3D structure with (4,8) connected nets. Temperature dependent dielectric measurements showed that compound 1 behaves as a high dielectric material with a high dielectric constant (κ = 45.1) at 5 kHz and 310 K, which is comparable to the values for some of the most commonly available dielectric inorganic metal oxides such as Sm2O3, Ta2O5, HfO2, and ZrO2. In addition, electrical measurements of 1 revealed an electrical conductivity of about 2.15 × 10-7 S/cm at a frequency of 5 kHz with a low leakage current (Ileakage = 8.13 × 10-12 Amm-2). Dielectric investigations of the Sm-based MOF provide an effective path for the development of high dielectric materials in the future.

  13. Pyroelectric properties and electrical conductivity in samarium doped BiFeO 3 ceramics

    KAUST Repository

    Yao, Yingbang

    2012-06-01

    Samarium (Sm 3+) doped BiFeO 3 (BFO) ceramics were prepared by a modified solid-state-reaction method which adopted a rapid heating as well as cooling during the sintering process. The pyroelectric coefficient increased from 93 to 137 μC/m 2 K as the Sm 3+ doping level increased from 1 mol% to 8 mol%. Temperature dependence of the pyroelectric coefficient showed an abrupt decrease above 80 °C in all samples, which was associated with the increase of electrical conductivity with temperature. This electrical conduction was attributed to oxygen vacancy existing in the samples. An activation energy of ∼0.7 eV for the conduction process was found to be irrespective of the Sm 3+ doping level. On the other hand, the magnetic Néel temperature (T N) decreased with increasing Sm 3+ doping level. On the basis of our results, the effects of Sm doping level on the pyroelectric and electrical properties of the BFO were revealed. © 2011 Elsevier Ltd. All rights reserved.

  14. Characterization of luminescent samarium doped HfO{sub 2} coatings synthesized by spray pyrolysis technique

    Energy Technology Data Exchange (ETDEWEB)

    Chacon-Roa, C [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Legaria 694, Col. Irrigacion, C.P. 11500, Mexico D.F. (Mexico); Guzman-Mendoza, J [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Legaria 694, Col. Irrigacion, C.P. 11500, Mexico D.F. (Mexico); Aguilar-Frutis, M [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Legaria 694, Col. Irrigacion, C.P. 11500, Mexico D.F. (Mexico); Garcia-Hipolito, M [Departamento de Materiales Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, A.P. 70-360 Coyoacan 04510, Mexico, D.F. (Mexico); Alvarez-Fragoso, O [Departamento de Materiales Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, A.P. 70-360 Coyoacan 04510, Mexico, D.F. (Mexico); Falcony, C [Departamento de Fisica, CINVESTAV-IPN, A. P. 14-740, 07000 Mexico D.F. (Mexico)

    2008-01-07

    Trivalent samarium (Sm{sup 3+}) doped hafnium oxide (HfO{sub 2}) films were deposited using the spray pyrolysis deposition technique. The films were deposited on Corning glass substrates at temperatures ranging from 300 to 550 deg. C using chlorides as raw materials. Films, mostly amorphous, were obtained when deposition temperatures were below 350 deg. C. However, for temperatures higher than 400 deg. C, the films became polycrystalline, presenting the HfO{sub 2} monoclinic phase. Scanning electron microscopy of the films revealed a rough surface morphology with spherical particles. Also, electron energy dispersive analysis was performed on these films. The photoluminescence and cathodoluminescence characteristics of the HfO{sub 2} : SmCl{sub 3} films, measured at room temperature, exhibited four main bands centred at 570, 610, 652 and 716 nm, which are due to the well-known intra-4f transitions of the Sm{sup 3+} ion. It was found that the overall emission intensity rose as the deposition temperature was increased. Furthermore, a concentration quenching of the luminescence intensity was also observed.

  15. Samarium-153 EDTMP for metastatic bone pain palliation: the impact of europium impurities.

    Science.gov (United States)

    Kalef-Ezra, J A; Valakis, S T; Pallada, S

    2015-02-01

    To evaluate the impact on the radiation protection policies of the radiocontaminants in Samarium-153 ethylenediamine tetramethylene phosphonate ((153)Sm-EDTMP). The internal contamination of patients treated with (153)Sm-EDMTP for palliation of painful disseminated multiple bone metastases due to long-lived impurities was assessed by direct measurements. These measurements were coupled with dose-rate measurements close to their bodies and spectroscopic analysis of the residual activity in post-treatment radiopharmaceutical vials. Whole-body counting carried out in six patients showed a 30-81-kBq europium -152 plus europium-154 contamination. The 0.85 mean (152)Eu- to -(154)Eu activity ratio obtained by direct counting was similar to that assessed by analysis of post-treatment residual activities in twelve radiopharmaceutical vials following radiopharmaceutical injection. The long-lived radiocontaminants in the patient's bodies and the treatment wastes require modifications of the applicable radiation protection policies. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  16. Luminescence of trivalent samarium ions in silver and tin co-doped aluminophosphate glass

    Science.gov (United States)

    Jiménez, José A.; Lysenko, Sergiy; Liu, Huimin; Sendova, Mariana

    2011-06-01

    This work presents the spectroscopic properties of trivalent samarium ions in a melt-quenched aluminophosphate glass containing silver and tin. Addition of 4 mol% of each Ag 2O and SnO into the glass system with 2 mol% Sm 2O 3 results in Sm 3+ ions luminescence under non-resonant UV excitation owing to energy transfer from single silver ions and/or twofold-coordinated Sn centers. Assessment of luminescence spectra and decay dynamics suggest the energy transfer mechanism to be essentially of the resonant radiative type. Moreover, a connection between the luminescent and structural properties of the rare-earth doped glass system was demonstrated. Raman spectroscopy characterization revealed that no significant variation in the glass matrix is induced by Sm 3+ doping at the concentration employed. A comparison was made with a structural study performed on the Eu 3+ doped system (containing 2 mol% Eu 2O 3 along with 4 mol% of each Ag 2O and SnO) where the radiative energy transfer mechanism was previously established. The data appears consistent regarding the lack of variation in glass structure upon the Eu 3+ and Sm 3+ doping in connection with the dominance of the radiative transfer in the matrix. Thermal treatment of the material leads to precipitation of Ag nanoparticles of a broad size range inside the dielectric as observed by transmission electron microspcopy. Assessment of 4G 5/2 excited state decay in Sm 3+ ions shows no influence from the silver particles.

  17. Samarium (III) adsorption on bentonite modified with N-(2-hydroxyethyl) ethylenediamine.

    Science.gov (United States)

    Li, Dandan; Chang, Xijun; Hu, Zheng; Wang, Qihui; Li, Ruijun; Chai, Xiaoli

    2011-02-15

    A new material has been synthesized using dry process to activate bentonite followed by N-(2-hydroxyethyl) ethylenediamine connecting chlorosilane coupling agent. The synthesized new material was characterized by elemental analysis, FT-IR and thermogravimetry which proved that bentonite was successfully modified. The most interesting trait of the new material was its selective adsorption for rare earth elements. A variety of conditions of the new material were investigated for adsorption. The optimal conditions were determined with respect to pH and shaking time. Samarium (Sm) was quantitatively adsorbed at pH 4 and shaking time of 2 min onto the new material. Under these conditions the maximum static adsorption capacity of Sm(III) was found to be 17.7 mg g(-1). The adsorbed Sm(III) ion were quantitatively eluted by 2.0 mL 0.1 mol L(-1) HCl and 5% CS (NH(2))(2) solution. According to IUPAC definition, the detection limit (3σ) of this method was 0.60 ng mL(-1). The relative standard deviation (RSD) under optimum conditions was less than 3% (n=8). The new material also was applied for the preconcentration of trace Sm(III) in environmental samples with satisfactory results. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Synthesis of Binary Transition Metal Nitrides, Carbides and Borides from the Elements in the Laser-Heated Diamond Anvil Cell and Their Structure-Property Relations

    Science.gov (United States)

    Friedrich, Alexandra; Winkler, Björn; Juarez-Arellano, Erick A.; Bayarjargal, Lkhamsuren

    2011-01-01

    Transition metal nitrides, carbides and borides have a high potential for industrial applications as they not only have a high melting point but are generally harder and less compressible than the pure metals. Here we summarize recent advances in the synthesis of binary transition metal nitrides, carbides and borides focusing on the reaction of the elements at extreme conditions generated within the laser-heated diamond anvil cell. The current knowledge of their structures and high-pressure properties like high-(p,T) stability, compressibility and hardness is described as obtained from experiments. PMID:28824101

  19. Synthesis of Binary Transition Metal Nitrides, Carbides and Borides from the Elements in the Laser-Heated Diamond Anvil Cell and Their Structure-Property Relations

    Directory of Open Access Journals (Sweden)

    Lkhamsuren Bayarjargal

    2011-09-01

    Full Text Available Transition metal nitrides, carbides and borides have a high potential for industrial applications as they not only have a high melting point but are generally harder and less compressible than the pure metals. Here we summarize recent advances in the synthesis of binary transition metal nitrides, carbides and borides focusing on the reaction of the elements at extreme conditions generated within the laser-heated diamond anvil cell. The current knowledge of their structures and high-pressure properties like high-(p; T stability, compressibility and hardness is described as obtained from experiments.

  20. Computational-Experimental Processing of Boride/Carbide Composites by Reactive Infusion of Hf Alloy Melts into B4C

    Science.gov (United States)

    2015-09-16

    PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) UNIVERSITY OF TEXAS AT EL PASO 500 UNIV ST ADMIN BLDG 209 EL PASO, TX 79968-0001 US 8. PERFORMING...Arturo Bronson UNIVERSITY OF TEXAS AT EL PASO Final Report 09/16/2015 DISTRIBUTION A: Distribution approved for public release. AF Office Of Scientific...University of Texas at El Paso July 2015 Bronson-Kumar (University of Texas at El Paso) 1 Computational-Experimental Processing of Boride/Carbide Composites

  1. Novel class of heterometallic cubane and boride clusters containing heavier group 16 elements.

    Science.gov (United States)

    Thakur, Arunabha; Sao, Soumik; Ramkumar, V; Ghosh, Sundargopal

    2012-08-06

    Thermolysis of an in situ generated intermediate, produced from the reaction of [Cp*MoCl(4)] (Cp* = η(5)-C(5)Me(5)) and [LiBH(4).THF], with excess Te powder yielded isomeric [(Cp*Mo)(2)B(4)TeH(5)Cl] (2 and 3), [(Cp*Mo)(2)B(4)(μ(3)-OEt)TeH(3)Cl] (4), and [(Cp*Mo)(4)B(4)H(4)(μ(4)-BH)(3)] (5). Cluster 4 is a notable example of a dimolybdaoxatelluraborane cluster where both oxygen and tellurium are contiguously bound to molybdenum and boron. Cluster 5 represents an unprecedented metal-rich metallaborane cluster with a cubane core. The dimolybdaheteroborane 2 was found to be very reactive toward metal carbonyl compounds, and as a result, mild pyrolysis of 2 with [Fe(2)(CO)(9)] yielded distorted cubane cluster [(Cp*Mo)(2)(BH)(4)(μ(3)-Te){Fe(CO)(3)}] (6) and with [Co(2)(CO)(8)] produced the bicapped pentagonal bipyramid [(Cp*MoCo)(2)B(3)H(2)(μ(3)-Te)(μ-CO){Co(3)(CO)(6)}] (7) and pentacapped trigonal prism [(Cp*MoCo)(2)B(3)H(2)(μ(3)-Te)(μ-CO)(4){Co(6)(CO)(8)}] (8). The geometry of 8 is an example of a heterometallic boride cluster in which five Co and one Mo atom define a trigonal prismatic framework. The resultant trigonal prism core is in turn capped by two boron, one Te, and one Co atom. In the pentacapped trigonal prism unit of 8, one of the boron atoms is completely encapsulated and bonded to one molybdenum, one boron, and five cobalt atoms. All the new compounds have been characterized in solution by IR, (1)H, (11)B, and (13)C NMR spectroscopy, and the structural types were unambiguously established by crystallographic analysis of 2 and 4-8.

  2. Microstructural evaluation of a low carbon steel submitted to boriding treatment pre and post GTAW welding; Avaliacao microestrutural de um aco de baixo carbono submetido ao tratamento de boretacao pre e pos-soldagem GTAW

    Energy Technology Data Exchange (ETDEWEB)

    Pollnow, Edilson Nunes; Osorio, Alice Goncalves, E-mail: edilson.pollnow@hotmail.com, E-mail: osorio.alice@gmail.com [Universidade Federal de Pelotas (CDTec/UFPel), Pelotas, RS (Brazil). Centro de Desenvolvimento Tecnologico; Araujo, Douglas Bezerra de, E-mail: dbaraujo@ufu.br [Universidade Federal de Uberlandia (FEMEC/UFU), Uberlandia, MG (Brazil). Faculdade de Engenharia Mecanica; Passos, Thais Andrezza dos; Souza, Daniel, E-mail: thais.andrezza.passos@gmail.com, E-mail: danielsouza@furg.br [Universidade Federal do Rio Grande (EE/FURG), Rio Grande, RS (Brazil). Escola de Engenharia

    2017-04-15

    Studies on surface engineering area are given great importance due to the improvement that surface modifications provide to materials. With a global market that has the need to provide parts and equipment with extended service life and low cost, to support stringent requests and thus maintain its high performance, surface treatments may bring what was impossible into reality. Among the surface treatments that have received attention recently, we have the thermochemical process of boriding. The boriding process consists of saturate the surface of steels and metal alloys with boron. This saturation provides an increase in the surface properties not inherent to the base metal, such as hardness, resistance to abrasion and corrosion. Although the properties of boriding steels have already been studied, the effects that the boriding process perform on the steel during or after the welding processes are not known. Hence, it is the purpose of this study to evaluate the microstructure of a low carbon steel treated with boriding before and after GTAW welding. The results indicated poor metallurgical weldability of low carbon steel with boride layer, with the presence of solidification cracks. Nonetheless, the steel welded previous to boring treatment presented a more ductile nucleus, with harder surface. Although the values of hardness within the nucleus of the steel had dropped drastically at the welded zone after the boring, the surface of this steel showed higher values of hardness due to the boriding layer. This fact should be considered when applications where wear resistance is needed. (author)

  3. Samarium oxide as a radiotracer to evaluate the in vivo biodistribution of PLGA nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mandiwana, Vusani, E-mail: VMandiwana@csir.co.za; Kalombo, Lonji, E-mail: LKalombo@csir.co.za [Centre of Polymers and Composites, CSIR (South Africa); Venter, Kobus, E-mail: Kobus.Venter@mrc.ac.za [South African Medical Research Council (South Africa); Sathekge, Mike, E-mail: Mike.Sathekge@up.ac.za [University of Pretoria and Steve Biko Academic Hospital, Department of Nuclear Medicine (South Africa); Grobler, Anne, E-mail: Anne.Grobler@nwu.ac.za; Zeevaart, Jan Rijn, E-mail: zeevaart@necsa.co.za [North-West University, DST/NWU Preclinical Drug Development Platform (South Africa)

    2015-09-15

    Developing nanoparticulate delivery systems that will allow easy movement and localization of a drug to the target tissue and provide more controlled release of the drug in vivo is a challenge in nanomedicine. The aim of this study was to evaluate the biodistribution of poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles containing samarium-153 oxide ([{sup 153}Sm]Sm{sub 2}O{sub 3}) in vivo to prove that orally administered nanoparticles alter the biodistribution of a drug. These were then activated in a nuclear reactor to produce radioactive {sup 153}Sm-loaded-PLGA nanoparticles. The nanoparticles were characterized for size, zeta potential, and morphology. The nanoparticles were orally and intravenously (IV) administered to rats in order to trace their uptake through imaging and biodistribution studies. The {sup 153}Sm-loaded-PLGA nanoparticles had an average size of 281 ± 6.3 nm and a PDI average of 0.22. The zeta potential ranged between 5 and 20 mV. The [{sup 153}Sm]Sm{sub 2}O{sub 3} loaded PLGA nanoparticles, orally administered were distributed to most organs at low levels, indicating that there was absorption of nanoparticles. While the IV injected [{sup 153}Sm]Sm{sub 2}O{sub 3}-loaded PLGA nanoparticles exhibited the highest localization of nanoparticles in the spleen (8.63 %ID/g) and liver (3.07 %ID/g), confirming that nanoparticles are rapidly removed from the blood by the RES, leading to rapid uptake in the liver and spleen. From the biodistribution data obtained, it is clear that polymeric nanoscale delivery systems would be suitable for improving permeability and thus the bioavailability of therapeutic compounds.

  4. Samarium oxide as a radiotracer to evaluate the in vivo biodistribution of PLGA nanoparticles

    Science.gov (United States)

    Mandiwana, Vusani; Kalombo, Lonji; Venter, Kobus; Sathekge, Mike; Grobler, Anne; Zeevaart, Jan Rijn

    2015-09-01

    Developing nanoparticulate delivery systems that will allow easy movement and localization of a drug to the target tissue and provide more controlled release of the drug in vivo is a challenge in nanomedicine. The aim of this study was to evaluate the biodistribution of poly( d, l-lactide- co-glycolide) (PLGA) nanoparticles containing samarium-153 oxide ([153Sm]Sm2O3) in vivo to prove that orally administered nanoparticles alter the biodistribution of a drug. These were then activated in a nuclear reactor to produce radioactive 153Sm-loaded-PLGA nanoparticles. The nanoparticles were characterized for size, zeta potential, and morphology. The nanoparticles were orally and intravenously (IV) administered to rats in order to trace their uptake through imaging and biodistribution studies. The 153Sm-loaded-PLGA nanoparticles had an average size of 281 ± 6.3 nm and a PDI average of 0.22. The zeta potential ranged between 5 and 20 mV. The [153Sm]Sm2O3 loaded PLGA nanoparticles, orally administered were distributed to most organs at low levels, indicating that there was absorption of nanoparticles. While the IV injected [153Sm]Sm2O3-loaded PLGA nanoparticles exhibited the highest localization of nanoparticles in the spleen (8.63 %ID/g) and liver (3.07 %ID/g), confirming that nanoparticles are rapidly removed from the blood by the RES, leading to rapid uptake in the liver and spleen. From the biodistribution data obtained, it is clear that polymeric nanoscale delivery systems would be suitable for improving permeability and thus the bioavailability of therapeutic compounds.

  5. Fabrication and properties of samarium doped calcium sulphate thin films using spray pyrolysis technique

    Energy Technology Data Exchange (ETDEWEB)

    Reghima, Meriem [Université Tunis El Manar, Faculté des Sciences de Tunis, Département de Physique, LR99ES13 Laboratoire de Physique de la Matière Condensée (LPMC), 2092 Tunis, Tunisie (Tunisia); Institut d' Electronique et des systèmes, Unité Mixte de Recherche 5214 UM2-CNRS (ST2i) – Université Montpellier, 860 rue de Saint Priest, Bâtiment 5, 34097 Montpellier (France); Faculté des Sciences de Bizerte, Université de Carthage, Zarzouna 7021 (Tunisia); Guasch, Cathy [Institut d' Electronique et des systèmes, Unité Mixte de Recherche 5214 UM2-CNRS (ST2i) – Université Montpellier, 860 rue de Saint Priest, Bâtiment 5, 34097 Montpellier (France); Azzaza, Sonia; Alleg, Safia [Laboratoire de Magnétisme et Spectroscopie des Solides (LM2S), Département de Physique, Faculté des Sciences, Université Badji Mokhtar Annaba, B.P. 12, 23000 Annaba (Algeria); Kamoun-Turki, Najoua [Université Tunis El Manar, Faculté des Sciences de Tunis, Département de Physique, LR99ES13 Laboratoire de Physique de la Matière Condensée (LPMC), 2092 Tunis, Tunisie (Tunisia)

    2016-10-01

    Using low cost spray pyrolysis technique, polycrystalline CaSO{sub 4} thin films were successfully grown on a glass substrate with a thickness of about 1 μm. Samarium doping has been performed on CaSO{sub 4} thin films to explore luminescence properties. The characterizations of these films were carried out using X-ray diffraction, Scanning Electron Microscopy and optical measurements. The structural analyses reveal the existence of hexagonal CaSO{sub 4} phase with a (200) preferred orientation belonging to CaS compound for substrate temperatures below 350 °C. It is shown that the crystallinity of the sprayed thin films can be improved by increasing substrate temperature up to 250 °C. Warren-Averbach analysis has been applied on X-ray diffractogram to determine structural parameters involving the phase with its amount, the grain size and the lattice parameters using Maud software. The surface topography shows a rough surface covered by densely packed agglomerated clusters having faceted and hexagonal shapes. Energy dispersive microscopy measurements confirm the presence of calcium and sulfur in equal proportions as well as high percentage of oxygen. Photoluminescence at room temperature revealed that luminescence peaks are attributed to the intrinsic emission of pure CaSO{sub 4} phase. - Highlights: • Warren Averbach analysis reveal the presence of hcp structure of CaSO{sub 4} phase. • A mixture of CaSO{sub 4} and CaHO{sub 4.5}S phases has been detected for lower T{sub s}. • For increasing T{sub s}, the CaHO{sub 4.5}S phase has been disappeared. • The origin of PL peaks has been identified.

  6. Kinetics of electrolysis current reversal boriding of tool steels in a boron-containing oxychloride melt based on CaCl2

    Science.gov (United States)

    Chernov, Ya. B.; Filatov, E. S.

    2017-08-01

    The kinetics of thermal diffusion boriding in a melt based on calcium chloride with a boron oxide additive is studied using reversed current. The main temperature, concentration, and current parameters of the process are determined. The phase composition of the coating is determined by a metallographic method.

  7. High-pressure study on borides, nanocrystals and negative thermal expansion materials

    Science.gov (United States)

    Chen, Bin

    2001-07-01

    By the use of Mao-Bell diamond anvil cell, employed with x-ray diffraction, optical absorption, Raman and Fourier Transform Infrared (FTIR) spectroscopy, iron borides, nanocrystalline Ni, Fe, Ni3Fe, Al2O 3, Negative Thermal Expansion (NTE) materials such as HfW2O 8, ZrW2O8, ZrMo2O8 have been studied under high pressure. The results of a synchrotron x-ray diffraction study of Fe2B under quasi-hydrostatic conditions from 0 to 50 GPa are reported. Over this pressure range, no phase change or disproportionation has been observed. A value of the bulk modulus, K, of 192 +/- 14 GPa and the first pressure derivative of the bulk modulus, K', of 2.6 +/- 0.6, are obtained. The compression is found to be anisotropic, with the a-axis being more incompressible than the c-axis. X-ray diffraction data of nanocrystalline Ni, Fe and Ni3Fe, using a synchrotron source, was collected under nonhydrostatic and quasi-hydrostatic conditions up to 60 GPa. The bulk moduli, of 185.4 +/- 10 GPa, 171 +/- 5 GPa, 179.4 +/- 8.1 GPa, 168.3 +/- 2.6 GPa, are determined from quasi-hydrostatic compression data of nanocrystalline Ni, alpha-Fe, epsilon-Fe and Ni3Fe, respectively, which are found similar to those of large-grained counterparts. Their phase transformations are studied and compared with their bulk counterparts. A new phase of Al2O3 formed by compression of the nanocrystalline gamma-phase has been detected. This high-pressure phase is metastable upon decompression to ambient pressure, and has a bulk modulus of 251 +/- 10 GPa for Al2O3 of 67 nm. From hydrostatic compression, bulk moduli of K67 = 238 +/- 3 GPa and K37 = 172 +/- 3 GPa are obtained for the 67 nm and 37 nm gamma-Al2O3 particles, respectively, which are significantly higher than that found in a previous study of smaller sized nanocrystals of gamma-alumina (K20 = 162 +/- 14 GPa for 20 nm crystallites). High pressure optical absorption, Raman and FTIR measurements are carried out on negative thermal expansion materials: HfW2O8, ZrW2O

  8. Optical properties and electronic transitions of zinc oxide, ferric oxide, cerium oxide, and samarium oxide in the ultraviolet and extreme ultraviolet

    DEFF Research Database (Denmark)

    Pauly, N; Yubero, F; Espinós, J P

    2017-01-01

    Optical properties and electronic transitions of four oxides, namely zinc oxide, ferric oxide, cerium oxide, and samarium oxide, are determined in the ultraviolet and extreme ultraviolet by reflection electron energy loss spectroscopy using primary electron energies in the range 0.3-2.0 keV. This...

  9. Optical response and magnetic characteristic of samarium doped zinc phosphate glasses containing nickel nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Azmi, Siti Amlah M.; Sahar, M.R., E-mail: mrahim057@gmail.com

    2015-11-01

    A magnetic glass of composition 40ZnO–(58−x) P{sub 2}O{sub 5}–1Sm{sub 2}O{sub 3}–xNiO, with x=0.0, 1.0, 1.5 and 2.0 mol% is prepared by melt-quenching technique. The glass is characterized by X-ray diffraction, high-resolution transmission electron microscope (HRTEM), photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM) analysis. The X-rays diffraction confirms the amorphous nature of the glass while the HRTEM analysis reveals the presence of nickel nanoparticles in the glass samples. High-resolution TEM reveals that the lattice spacing of nickel nanoparticles is 0.35 nm at (100) plane. Photoluminescence emission shows the existence of four peaks that correspond to the transition from the upper level of {sup 4}G{sub 5/2} to the lower level of {sup 6}H{sub 5/2}, {sup 6}H{sub 7/2}, {sup 6}H{sub 9/2,} and {sup 6}H{sub 11/2.} It is observed that all peaks experience significant quenching effect with the increasing concentration of nickel nanoparticles, suggesting a strong energy transfer from excited samarium ions to the nickel ions. The glass magnetization and susceptibility at 12 kOe at room temperature are found to be in the range of (3.87±0.17×10{sup −2}–7.19±0.39×10{sup −2}) emu/g and (3.24±0.16×10{sup −6}–5.99±0.29×10{sup −6}) emu/Oe g respectively. The obtained hysteresis curve indicates that the glass samples are paramagnetic materials. The studied glass can be further used towards the development of magneto-optical functional glass. - Highlights: • Sm{sup 3+} doped zinc phosphate glass embedded with Ni NPs has been prepared. • The Laue pattern and lattice spacing of Ni NPs are confirmed by HRTEM image. • The magnetic response of glasses has been studied through VSM analysis. • Enhancement factor and decay half-lifetime are investigated.

  10. Treatment of bone pain secondary to metastases using samarium-153-EDTMP

    Directory of Open Access Journals (Sweden)

    Elba Cristina Sá de Camargo Etchebehere

    Full Text Available CONTEXT: More than 50% of patients with prostate, breast or lung cancer will develop painful bone metastases. The purpose of treating bone metastases is to relieve pain, reduce the use of steroids and to maintain motion. OBJECTIVE: To evaluate the use of samarium-153-EDTMP (153Sm-EDTMP for the treatment of bone pain secondary to metastases that is refractory to clinical management. TYPE OF STUDY: Retrospective. SETTING: Division of Nuclear Medicine, Universidade Estadual de Campinas (Unicamp. METHODS: Fifty-eight patients were studied (34 males with mean age 62 years; 31 patients had prostate cancer, 20 had breast cancer, three had lung cancer, one had lung hemangioendothelioma, one had parathyroid adenocarcinoma, one had osteosarcoma and one had an unknown primary tumor. All patients had multiple bone metastases demonstrated by bone scintigraphy using 99mTc-MDP,and were treated with 153Sm-EDTMP. Response to treatment was graded as good (pain reduction of 50-100%, intermediate (25-49% and poor (0-24%. RESULTS: All patients showed good uptake of 153Sm-EDTMP by bone metastases. Among the patients with prostate cancer, intermediate or good response to therapy occurred in 80.6% (25 patients and poor response in 19.4% (6. Among the patients with breast cancer, 85% (17 showed intermediate or good response to therapy while 15% (3 showed poor response. All three patients with lung cancer showed poor response to treatment. The lung hemangioendothelioma and unknown primary lesion patients showed intermediate response to treatment; the osteosarcoma and parathyroid adenocarcinoma patients showed good response to treatment. No significant myelotoxicity occurred. DISCUSSION: Pain control is important for improving the quality of life of patients with advanced cancers. The mechanism by which pain is relieved with the use of radionuclides is still not yet completely understood, however, the treatment is simple and provides a low risk of mielotoxicity

  11. Anchoring samarium oxide nanoparticles on reduced graphene oxide for high-performance supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Dezfuli, Amin Shiralizadeh [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Ganjali, Mohammad Reza, E-mail: ganjali@khayam.ut.ac.ir [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Biosensor Research Center, Endocrinology & Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Naderi, Hamid Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)

    2017-04-30

    Highlights: • Samarium oxide nanoparticles have been anchored on the surface of reduced graphene oxide for the first time. • Sm{sub 2}O{sub 3}/RGO nanocomposite show high capacitance, good rate and cycling performance. • Sm{sub 2}O{sub 3}/RGO nanocomposite can serve as efficient electrode material for energy storage. • The best composite electrode exhibits specific capacitance of 321 F g{sup −1} in 2 mV s{sup −1}. - Abstract: We have synthesized Sm{sub 2}O{sub 3} nanoparticles (SmNs) and anchored them onto the surface of reduced graphene oxide (RGO) through a self-assembly thereof by utilizing a facile sonochemical procedure. The nanomaterials were characterized by means of powder X-ray diffraction (XRD), Field-emission scanning electron microscopy (FE-SEM), fourier transform infrared spectroscopy (FT-IR) spectra, and X-ray photoelectron spectroscopy (XPS). As the next step, the supercapacitive behavior of the resulting nanocomposites were investigated when used as electrode material, through with cyclic voltammetric (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) techniques. The SmNs decorated RGO (SmN-RGO) nanocomposites were found to possess a specific capacitance (SC) of 321 F g{sup −1} when used in a 0.5 M Na{sub 2}SO{sub 4} solution as an electrolyte, in a scan rate of 2 mV s{sup −1}. The SC of the SmN-RGO based electrodes were also found to be 268 F g{sup −1} at a current density of 2 A g{sup −1} through galvanostatic charge-discharge tests. The outstanding properties of the SmN-RGOs were attributed to synergy of the high charge mobility of SmNs and the flexibility of the sheets of RGOs. Additionally, the nano-composite revealed a unique cycling durability (maintaining 99% of its SC even after 4000 cycles).

  12. Thermodynamic modelling of phase equilibrium in system Ti-B-Si-C, synthesis and phases composition of borides and carbides layers on titanic alloyVT-1 at electron beam treatment in vacuum

    Science.gov (United States)

    Smirnyagina, N. N.; Khaltanova, V. M.; Lapina, A. E.; Dasheev, D. E.

    2017-01-01

    Composite layers on the basis of carbides and borides the titan and silicon on titanic alloy VT-1 are generated at diffused saturation in vacuum. Formation in a composite of MAX phase Ti3SiC2 is shown. Thermodynamic research of phase equilibrium in systems Ti-Si-C and Ti-B-C in the conditions of high vacuum is executed. The thermodynamics, formation mechanisms of superfirm layers borides and carbides of the titan and silicon are investigated.

  13. Synthesis, characterization and investigation of thermoelectric properties of selected metal borides; Synthese, Charakterisierung und Untersuchung thermoelektrischer Eigenschaften ausgewaehlter Metallboride

    Energy Technology Data Exchange (ETDEWEB)

    Stober, Frederick

    2012-06-04

    The present work deals with the high-temperature thermoelectric properties of transition metal [eg V, Cr, Mn, Ni, Cu] and lanthanide [e.g. Sc, Y, Gd, Er, Dy]-borides. In particular, intercalation compounds of beta-rhombohedral boron, compounds of the type MB{sub 66}, dodecaborides and hexaborides were examined. In the case of intercalation compounds of beta-rhombohedral boron it was found that the incorporation of metals such as Sc, Mn or Cu result in favorable thermoelectric properties. The reason is most likely the preferred occupation of the metal position M2 instead of M4. Composites, for example, DyB{sub 66}-DyB{sub 12} show high electrical conductivities, high Seebeck effects at high temperatures due to the presence of DyB{sub 12} and low thermal conductivities as a result of the DyB{sub 66} matrix. At 1100K the composite DyB{sub 66}-DyB{sub 12} shows a ZT value of 0.55, thus exceeding the ZT of boron carbide (B{sub 13}C{sub 2}) at this temperature which is considered the best p-type boride material. A composite of ErB{sub 12}-ErB{sub 4}-ErB{sub 2} has negative Seebeck coefficients and shows a ZT value of 0.5 at 840K. Furthermore, the structure of tetragonal Scandiumdodecaboride ScB{sub 12} was solved on the basis of synchrotron data from a crystalline powder, after it has been debated for decades but never fully resolved.

  14. Effect of Current Density on Thermodynamic Properties of Nanocrystalline Palladium Capped Samarium Hydride Thin Film Switchable Mirrors

    Directory of Open Access Journals (Sweden)

    Pushpendra Kumar

    2007-01-01

    Full Text Available A 55 nm samarium film capped with a 10 nm palladium overlayer switched from a metallic reflecting to a semiconducting, transparent in visible state during ex-situ hydrogen loading via electrochemical means in 1 M KOH electrolytic aqueous solution at room temperature. The switching between metal to semiconductor was accompanied by measurement of transmittance during hydrogen loading/unloading. The effect of current density on switching and thermodynamic properties was studied between dihydride state (FCC phase and trihydride state (hexagonal phase. From the plateau of partial pressure of hydrogen at x=2.6, enthalpy of formation was calculated at different current densities. The diffusion coefficients and switching kinetics are shown to depend on applied current density.

  15. Targeted bone marrow radioablation with 153Samarium-lexidronam promotes allogeneic hematopoietic chimerism and donor-specific immunologic hyporesponsiveness.

    Science.gov (United States)

    Inverardi, Luca; Linetsky, Elina; Pileggi, Antonello; Molano, R Damaris; Serafini, Aldo; Paganelli, Giovanni; Ricordi, Camillo

    2004-03-15

    Transplantation tolerance, defined as acceptance of a graft by an otherwise fully immunocompetent host, has been an elusive goal. Although robust tolerance has been achieved by the induction of stable hematopoietic chimerism after bone marrow transplantation, lethal or sublethal radiation conditioning used to induce long-term chimerism precludes its clinical use. We studied whether targeted delivery of radiation to bone marrow could allow for bone marrow cell (BMC) engraftment, chimerism, and donor-specific tolerance in the absence of the side effects associated with external irradiation. We administered a radioactive bone-seeking compound (Samarium-Lexidronam, Quadramet, Berlex Laboratories, Wayne, NJ) together with transient T-cell costimulatory blockade to recipient mice. Allogeneic BMCs were given 7 or 14 days after preconditioning. Costimulatory blockade was obtained by the use of an anti-CD154 antibody for 4 weeks. Chimerism was assessed by flow cytometry. Mice then received donor-specific and third-party skin grafts. Graft survival was analyzed with mechanisms of donor-specific hyporesponsiveness. High levels of stable chimerism across an allogeneic barrier were achieved in mice by a single administration of Samarium-Lexidronam, transient T-cell costimulatory blockade, and BMC transplantation. A large percentage of chimeric animals retained donor-derived skin grafts for more than 120 days without requiring additional immunosuppression, suggesting that harsh cytotoxic preconditioning is not necessary to achieve stable chimerism and donor specific hyporesponsiveness. Analysis of the T-cell repertoire in chimeras indicates T-cell deletional mechanisms. These data broaden the potential use of BMC transplantation for tolerance induction and argue for its potential in treating autoimmune diseases.

  16. Sorption of samarium in soils: influence of soil properties and Sm concentration

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez-Guinart, Oriol; Salaberria, Aitor; Rigol, Anna; Vidal, Miquel [Analytical Chemistry department, Faculty of Chemistry, University of Barcelona, Marti i Franques 1-11, 08028, Barcelona (Spain)

    2014-07-01

    Due to the fact that barriers of Deep Geological Repositories (DGR) may lose efficiency before the radioisotopes present in the High Level Radioactive Waste (HLRW) completely decay, it is possible that, in the long-term, radioactive leachates may escape from the DGR and reach the soil and water compartments in the biosphere. Therefore, it is required to examine the interaction and mobility of radionuclides present in the HLRW, or their chemical analogues, to predict the impact of their eventual incorporation in the biosphere and to assess the derived risk. Although relevant data have been recently obtained for a few radionuclides in soils, there are still some important gaps for some radionuclides, such us for samarium (Sm). Sm is a lanthanide that, besides being considered as a natural analogue of actinides, may also be present in HLRW in the form of the radioactive isotope {sup 151}Sm. The main objective of this work was to obtain sorption data (K{sub d}) of {sup 151}Sm gathered from a set of soil samples physicochemical fully-characterized (pH, texture, cationic exchange capacity, soil solution cationic composition, organic matter, carbonate and metallic oxides content, etc.). Additionally, as an alternative for testing sorption capacity of radionuclides in soils is the use of the corresponding stable isotope or a chemical analogue, the influence of Sm concentration was also checked. To evaluate {sup 151}Sm sorption, batch assays were carried out for each soil sample, which consisted in a pre-equilibration step of 2 g of each soil with 50 ml of double deionised water, and a subsequent equilibration step with the same solution, but labelled with {sup 151}Sm. The activity of {sup 151}Sm in initial and final solutions was measured by liquid scintillation and K{sub d} ({sup 151}Sm) data were calculated. The reversibly sorbed fraction was estimated by the application of a single extraction test, with double deionised water, to soil residues coming from the previous

  17. Effect of the boride-nitride hardening on the structure and properties of chromium steel deposited with a flux-cored wire

    Science.gov (United States)

    Eremin, E. N.; Losev, A. S.; Borodikhin, S. A.; Ivlev, K. Ye.

    2017-08-01

    Reliability and durability of pipeline valves are largely determined by the resistance of weld sealing surfaces of its shut-off valve, which in its turn depends on the weld metal properties. To improve the durability of valves a new composition of a high chromium flux-cored wire with a boride compounds complex (BN, TiB2, ZrB2) producing weld composite metal is developed. It is stated that the formation of the martensitic matrix with a reduced structural fragments average size due to appearance of dispersed boride-nitride phases in this metal has resulted in high coating hardness and wear resistance. The original version of this article supplied to AIP Publishing was incomplete and omitted the acknowledgement statement. The full acknowledgement reads: The work was carried out at the expense of a grant from the Russian Science Foundation (No. 17-19-01224).

  18. Low-cost industrially available molybdenum boride and carbide as “platinum-like” catalysts for the hydrogen evolution reaction in biphasic liquid systems

    OpenAIRE

    Scanlon, Micheal Diarmaid; Bian, Xiaojun; Vrubel, Heron; Amstutz, Véronique; Schenk, Kurt; Hu, Xile; Liu, Baohong; Girault, Hubert

    2013-01-01

    Rarely reported low cost molybdenum boride and carbide microparticles both of which are available in abundant quantities due to their widespread use in industry adsorb at aqueous acid 12 dichloroethane interfaces and efficiently catalyse the hydrogen evolution reaction in the presence of the organic electron donor decamethylferrocene. Kinetic studies monitoring biphasic reactions by UV/vis spectroscopy and further evidence provided by gas chromatography highlight (a) their superior rates of c...

  19. Crystal growth of semiorganic complex- samarium chloride coordinated thiourea-L-tartaric acid and its studies on structure and optical characteristics

    Science.gov (United States)

    Slathia, Goldy; Singh, Harjinder; Ramya, E.; Rao, D. Narayana; Bamzai, K. K.

    2017-05-01

    The semi-organic complex of samarium chloride coordinated thiourea-L-tartaric acid (SCTLT) has been grown as a single crystal by slow evaporation technique at room temperature. For structural studies, the grown crystal was subjected to single crystal X-ray diffraction and Fourier transform infra-red (FTIR) spectroscopy. Low cut off wavelength and transparent characteristics were explored by UV-VIS optical characterization. Third-order nonlinear optical properties of grown crystal were investigated by Z-scan technique.

  20. Processing development of 4 tantalum carbide-hafnium carbide and related carbides and borides for extreme environments

    Science.gov (United States)

    Gaballa, Osama Gaballa Bahig

    Carbides, nitrides, and borides ceramics are of interest for many applications because of their high melting temperatures and good mechanical properties. Wear-resistant coatings are among the most important applications for these materials. Materials with high wear resistance and high melting temperatures have the potential to produce coatings that resist degradation when subjected to high temperatures and high contact stresses. Among the carbides, Al4SiC4 is a low density (3.03 g/cm3), high melting temperature (>2000°C) compound, characterized by superior oxidation resistance, and high compressive strength. These desirable properties motivated this investigation to (1) obtain high-density Al4SiC4 at lower sintering temperatures by hot pressing, and (2) to enhance its mechanical properties by adding WC and TiC to the Al4SiC4. Also among the carbides, tantalum carbide and hafnium carbide have outstanding hardness; high melting points (3880°C and 3890°C respectively); good resistance to chemical attack, thermal shock, and oxidation; and excellent electronic conductivity. Tantalum hafnium carbide (Ta4HfC 5) is a 4-to-1 ratio of TaC to HfC with an extremely high melting point of 4215 K (3942°C), which is the highest melting point of all currently known compounds. Due to the properties of these carbides, they are considered candidates for extremely high-temperature applications such as rocket nozzles and scramjet components, where the operating temperatures can exceed 3000°C. Sintering bulk components comprised of these carbides is difficult, since sintering typically occurs above 50% of the melting point. Thus, Ta4 HfC5 is difficult to sinter in conventional furnaces or hot presses; furnaces designed for very high temperatures are expensive to purchase and operate. Our research attempted to sinter Ta4HfC5 in a hot press at relatively low temperature by reducing powder particle size and optimizing the powder-handling atmosphere, milling conditions, sintering

  1. Sorption of samarium in iron (II) and (III) phosphates in aqueous systems; Sorcion de samario en fosfatos de hierro (II) y (III) en sistemas acuosos

    Energy Technology Data Exchange (ETDEWEB)

    Diaz F, J.C

    2006-07-01

    The radioactive residues that are stored in the radioactive confinements its need to stay isolated of the environment while the radioactivity levels be noxious. An important mechanism by which the radioactive residues can to reach the environment, it is the migration of these through the underground water. That it makes necessary the investigation of reactive materials that interacting with those radionuclides and that its are able to remove them from the watery resources. The synthesis and characterization of materials that can be useful in Environmental Chemistry are very important because its characteristics are exposed and its behavior in chemical phenomena as the sorption watery medium is necessary to use it in the environmental protection. In this work it was carried out the sorption study of the samarium III ion in the iron (II) and (III) phosphate; obtaining the sorption isotherms in function of pH, of the phosphate mass and of the concentration of the samarium ion using UV-visible spectroscopy to determine the removal percentage. The developed experiments show that as much the ferrous phosphate as the ferric phosphate present a great affinity by the samarium III, for what it use like reactive material in contention walls can be very viable because it sorption capacity has overcome 90% to pH values similar to those of the underground and also mentioning that the form to obtain these materials is very economic and simple. (Author)

  2. Trace amounts of rare earth elements in high purity samarium oxide by sector field inductively coupled plasma mass spectrometry after separation by HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Pedreira, W.R. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil) and Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho (FUNDACENTRO), 05409-002 Sao Paulo, SP (Brazil)]. E-mail: walter.pedreira@fundacentro.gov.br; Queiroz, C.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Abrao, A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Rocha, S.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Vasconcellos, M.E. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Boaventura, G.R. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil); Pimentel, M.M. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil)

    2006-07-20

    Today there is an increasing need for high purity rare earth compounds in various fields, the optical, the electronics, the ceramic, the nuclear and geochemistry. Samarium oxide has special uses in glass, phosphors, lasers and thermoelectric devices. Calcium chloride crystals treated with samarium have been employed in lasers, which produce light beams intense enough to burn metal. In general, the inductively coupled plasma mass spectrometry (ICP-MS) presents some advantages for trace element analysis, due to high sensitivity and resolution, when compared with other analytical techniques such as ICP optical emission spectrometry (ICP-OES). In this work, sector field inductively coupled plasma mass spectrometry was used. Sixteen elements (Sc, Y and 14 lanthanides) were determined selectively with the ICP-MS system using a concentration gradient method. The detection limits with the ICP-MS system were about 0.2 (La) pg mL{sup -1} to 8 (Gd) pg mL{sup -1}. The %R.S.D. of the methods varying between 0.9 and 1.5% for a set of five (n = 5) replicates was found for the IPEN's material and for the certificate reference sample. Determination of trace REEs in two high pure samarium oxides samples (IPEN and JMC) was performed. IPEN's material is highly pure (>99.99%) and was successfully analyzed without spectral interference (MO{sup +} and MOH{sup +})

  3. A novel route to nanosized molybdenum boride and carbide and/or metallic molybdenum by thermo-synthesis method from MoO 3, KBH 4, and CCl 4

    Science.gov (United States)

    Li, Yuanzhi; Fan, Yining; Chen, Yi

    2003-01-01

    Nanosized molybdenum boride and carbide were synthesized from MoO 3, KBH 4, and CCl 4 by thermo-synthesis method at lower temperature. The relative content of Mo, Mo 2C, and molybdenum boride in the product was decided by the molar ratio between MoO 3, KBH 4, and CCl 4. Increasing the molar ratio of CCl 4 to MoO 3 was favorable to the production of Mo 2C. Increasing the molar ratio of KBH 4 to MoO 3 was favorable to the production of molybdenum boride. By carefully adjusting the reaction conditions and annealing in Ar at 900°C, a single phase of MoB could be obtained.

  4. Two-phase zirconium boride thin film obtained by ultra-short pulsed laser ablation of a ZrB{sub 12} target

    Energy Technology Data Exchange (ETDEWEB)

    De Bonis, A., E-mail: angela.debonis@unibas.it [Dipartimento di Scienze, Università della Basilicata, Viale dell’Ateneo Lucano, 10 -85100 Potenza (Italy); Istituto di Metodologie Inorganiche e dei Plasmi, Consiglio Nazionale delle Ricerche, U.O.S. di Potenza, C.da Santa Loja, 85010 Tito Scalo, Potenza (Italy); Santagata, A. [Istituto di Metodologie Inorganiche e dei Plasmi, Consiglio Nazionale delle Ricerche, U.O.S. di Potenza, C.da Santa Loja, 85010 Tito Scalo, Potenza (Italy); Rau, J.V. [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Latini, A. [Università di Roma “La Sapienza”, Dipartimento di Chimica, Piazzale Aldo Moro, 5 -00185 Rome (Italy); Mori, T. [National Institute for Materials Science (NIMS) WPI Materials Nanoarchitectonics Center (MANA), Namiki 1-1, Tsukuba 305-0044 (Japan); Medici, L. [Istituto di Metodologie per le Analisi Ambientali, Consiglio Nazionale delle Ricerche, U.O.S. di Potenza, C.da Santa Loja, 85010 Tito Scalo, Potenza (Italy); Teghil, R. [Dipartimento di Scienze, Università della Basilicata, Viale dell’Ateneo Lucano, 10 -85100 Potenza (Italy)

    2013-10-15

    Two-phase zirconium boride thin films have been obtained by ultra-short pulsed laser ablation (PLA) of a zirconium dodecaboride (ZrB{sub 12}) target performed in vacuum. The ablation source was a frequency doubled (λ = 527 nm) Nd:glass laser with a pulse duration of 250 fs. Laser induced plasma has been studied by ICCD imaging and time and space resolved optical emission spectroscopy (OES), whereas the deposited films have been characterized by atomic force microscopy, scanning electron microscopy, X-Ray diffraction and micro-Raman spectroscopy. The film morphology and composition have been interpreted on the basis of the laser ablation mechanism.

  5. Effect of higher borides and inhomogeneity of oxygen distribution on critical current density of undoped and doped magnesium diboride

    Energy Technology Data Exchange (ETDEWEB)

    Prikhna, T A; Tkach, V M; Savchuk, Ya M; Dub, S N; Moshchil, V E; Kozyrev, A V; Sergienko, N V; Melnikov, V S; Shapovalov, A P [Institute for Superhard Materials of the NASU, 2, Avtozavodskaya Str., Kiev 04074 (Ukraine); Gawalek, W; Wendt, M; Dellith, J; Schmidt, Ch; Habisreuther, T; Litzkendorf, D [Institut fuer Photonische Technologien, Albert-Einstein-Strasse 9, Jena, D-07745 (Germany); Danilenko, N I [Institute for Problems of Materialscience of the National Academy of Sciences of Ukraine, 3, Krzhyzhanivsky Str., Kiev 03142 (Ukraine); Weber, H; Eisterer, M [Atomic Institute of the Austrian Universities, 1020 Vienna (Austria); Vajda, J [Budapest University of Technology and Economics, Budapest, Hungary 1111 Budapest, Egry Jozsef u. 18. (Hungary); Sokolovsky, V, E-mail: prikhna@iptelecom.net.u, E-mail: prikhna@mail.r [Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 84105 (Israel)

    2010-06-01

    The effect of doping with Ti, Ta, SiC in complex with synthesis temperature on the amount and distribution of structural inhomogeneities in MgB{sub 2} matrix of high-pressure-synthesized-materials (2 GPa) which can influence pinning: higher borides (MgB{sub 12}) and oxygen-enriched Mg-B-O inclusions, was established and a mechanism of doping effect on j{sub c} increase different from the generally accepted was proposed. Near theoretically dense SiC-doped material exhibited j{sub c}= 10{sup 6} A/cm{sup 2} in 1T field and H{sub irr} =8.5 T at 20 K. The highest jc in fields above 9, 6, and 4 T at 10, 20, and 25 K, respectively, was demonstrated by materials synthesized at 2 GPa, 600 {sup 0}C from Mg and B without additions (at 20 K j{sub c}= 10{sup 2} A/cm{sup 2} in 10 T field). Materials synthesized from Mg and B taken up to 1:20 ratio were superconductive. The highest j{sub c} (6x10{sup 4} A/cm{sup 2} at 20 K in zero field, H{sub irr}= 5 T) and the amount of SC phase (95.3% of shielding fraction), T{sub c} being 37 K were demonstrated by materials having near MgB{sub 12} composition of the matrix. The materials with MgB{sub 12} matrix had a doubled microhardness of that with MgB{sub 2} matrix (25{+-}1.1 GPa and 13.08{+-}1.07 GPa, at a load of 4.9 N, respectively).

  6. Effectiveness of radiation synovectomy with samarium-{sup 153} particulate hydroxyapatite in rheumatoid arthritis patients with knee synovitis: a controlled randomized double-blind trial

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Marla Francisca dos; Furtado, Rita Nely Vilar; Konai, Monique Sayuri; Natour, Jamil, E-mail: jnatour@unifesp.b [Universidade Federal de Sao Paulo (UNIFESP-EPM), Sao Paulo, SP (Brazil). Divisao de Reumatologia; Castiglioni, Mario Luiz Vieira; Marchetti, Renata Rosa [Universidade Federal de Sao Paulo (UNIFESP-EPM), Sao Paulo, SP (Brazil). Divisao de Medicina Nuclear

    2009-07-01

    Objectives: the aim of the present study was to investigate the effectiveness of Samarium{sup 153}-particulate hydroxyapatite radiation synovectomy in rheumatoid arthritis patients with chronic knee synovitis. Methods: fifty-eight rheumatoid arthritis patients (60 knees) with chronic knee synovitis participated in a controlled double-blinded trial. Patients were randomized to receive either an intra-articular injection with 40 mg triamcinolone hexacetonide alone (TH group) or 40 mg triamcinolone hexacetonide combined with 15 mCi Samarium{sup 153}-particulate hydroxyapatite (Sm/TH group). Blinded examination at baseline (T0) and at 1 (T1), 4 (T4), 12 (T12), 32 (T32), and 48 (T48) weeks post-intervention were performed on all patients and included a visual analog scale for joint pain and swelling as well as data on morning stiffness, flexion, extension, knee circumference, Likert scale of improvement, percentage of improvement, SF-36 generic quality of life questionnaire, Stanford Health Assessment Questionnaire (HAQ), Lequesne index, use of non-steroidal anti-inflammatory drugs or oral corticosteroids, events and adverse effects, calls to the physician, and hospital visits. Results: the sample was homogeneous at baseline, and there were no withdrawals. Improvement was observed in both groups in relation to T0, but no statistically significant differences between groups were observed regarding all variables at the time points studied. The Sm/TH group exhibited more adverse effects at T1 (p<0.05), but these were mild and transitory. No severe adverse effects were reported during follow-up. Conclusion: intra-articular injection of Samarium{sup 153}-particulate hydroxyapatite (15 mCi) with 40 mg of triamcinolone hexacetonide is not superior to triamcinolone hexacetonide alone for the treatment of knee synovitis in patients with rheumatoid arthritis at 1 y of follow-up. (author)

  7. The properties of samarium-doped zinc oxide/phthalocyanine structure for optoelectronics prepared by pulsed laser deposition and organic molecular evaporation

    Czech Academy of Sciences Publication Activity Database

    Novotný, Michal; Marešová, Eva; Fitl, Přemysl; Vlček, Jan; Bergmann, M.; Vondráček, Martin; Yatskiv, Roman; Bulíř, Jiří; Hubík, Pavel; Hruška, Petr; Drahokoupil, Jan; Abdellaoui, N.; Vrňata, M.; Lančok, Ján

    2016-01-01

    Roč. 122, č. 3 (2016), 1-8, č. článku 225. ISSN 0947-8396 R&D Projects: GA MŠk(CZ) LG15050; GA ČR(CZ) GAP108/11/0958; GA MŠk(CZ) LM2011029; GA ČR(CZ) GA14-10279S; GA MŠk(CZ) 7AMB14FR010 Institutional support: RVO:68378271 ; RVO:67985882 Keywords : samarium-doped zinc oxide zinc/phthalocyanine deposition * evaporation * pulsed laser deposition * thin films Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.455, year: 2016

  8. Neutron Activated Samarium-153 Microparticles for Transarterial Radioembolization of Liver Tumour with Post-Procedure Imaging Capabilities

    Science.gov (United States)

    Hashikin, Nurul Ab. Aziz; Yeong, Chai-Hong; Abdullah, Basri Johan Jeet; Ng, Kwan-Hoong; Chung, Lip-Yong; Dahalan, Rehir; Perkins, Alan Christopher

    2015-01-01

    Introduction Samarium-153 (153Sm) styrene divinylbenzene microparticles were developed as a surrogate for Yttrium-90 (90Y) microspheres in liver radioembolization therapy. Unlike the pure beta emitter 90Y, 153Sm possess both therapeutic beta and diagnostic gamma radiations, making it possible for post-procedure imaging following therapy. Methods The microparticles were prepared using commercially available cation exchange resin, Amberlite IR-120 H+ (620–830 μm), which were reduced to 20–40 μm via ball mill grinding and sieve separation. The microparticles were labelled with 152Sm via ion exchange process with 152SmCl3, prior to neutron activation to produce radioactive 153Sm through 152Sm(n,γ)153Sm reaction. Therapeutic activity of 3 GBq was referred based on the recommended activity used in 90Y-microspheres therapy. The samples were irradiated in 1.494 x 1012 n.cm-2.s-1 neutron flux for 6 h to achieve the nominal activity of 3.1 GBq.g-1. Physicochemical characterisation of the microparticles, gamma spectrometry, and in vitro radiolabelling studies were carried out to study the performance and stability of the microparticles. Results Fourier Transform Infrared (FTIR) spectroscopy of the Amberlite IR-120 resins showed unaffected functional groups, following size reduction of the beads. However, as shown by the electron microscope, the microparticles were irregular in shape. The radioactivity achieved after 6 h neutron activation was 3.104 ± 0.029 GBq. The specific activity per microparticle was 53.855 ± 0.503 Bq. Gamma spectrometry and elemental analysis showed no radioactive impurities in the samples. Radiolabelling efficiencies of 153Sm-Amberlite in distilled water and blood plasma over 48 h were excellent and higher than 95%. Conclusion The laboratory work revealed that the 153Sm-Amberlite microparticles demonstrated superior characteristics for potential use in hepatic radioembolization. PMID:26382059

  9. Preparation and examination of properties of samarium-153-EDTMP complex; Otrzymywanie chelatu kwasu etylenodiaminotetrametylenofosfonowego (EDTMP) z samarem-153 i badanie jego wlasciwosci

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, M. [Institute of Atomic Energy, Otwock-Swierk (Poland); Garnuszek, P.; Lukasiewicz, A.; Wozniak, I.; Zulczyk, W. [Osrodek Badawczo-Rozwojowy Izotopow, Otwock-Swierk (Poland); Licinska, I. [Instytut Lekow, Warsaw (Poland)

    1995-12-31

    Preparation and properties of ethylenediaminetetramethylenephosphonic acid (EDTMP) as well as some properties of {sup 153}Sm-EDTMP chelate have been examined. The chelate formed by samarium-153 (46.3 h, {beta}{sup -}-decay) with EDTMP exhibits high bone uptake and can be used for treatment of disseminated, painful skeletal metastases. The purity and stability of solutions of {sup 153}Sm-EDTMP chelate were examined in a broad range of samarium concentration and {sup 153}Sm specific activity. The complex under study was examined by radio-TLC, -electrophoresis and radio-HPLC. The results obtained suggest the small size of molecules of {sup 153}Sm-EDTMP chelate as compared with molecules of ``free``EDTMP. The results of biodistribution of {sup 153}Sm-EDTMP determined in rats indicate the quick blood clearance, high deposition of radioactivity in bone and quick excretion of radioactivity into urine. No specific uptake of {sup 153}Sm-EDTMP in extra-skeletal organs was found. (author). 42 refs, 13 figs, 22 tabs.

  10. The Level of Europium-154 Contaminating Samarium-153-EDTMP Activates the Radiation Alarm System at the US Homeland Security Checkpoints

    Directory of Open Access Journals (Sweden)

    Mohammed Najeeb Al Hallak

    2009-08-01

    Full Text Available 153Sm-EDTMP is a radiopharmaceutical composed of EDTMP (ethylenediamine-tetramethylenephosphonate and Samarium-153 [1]. 153Sm-EDTMP has an affinity for skeletal tissue and concentrates in areas with increased bone turnover; thus, it is successfully used in relieving pain related to diffuse bone metastases [1]. The manufacturing process of 153Sm-EDTMP leads to contamination with 154Eu (Europium-154 [2]. A previous study only alluded to the retention of 154Eu in the bones after receiving treatment with 153Sm-EDTMP [2]. Activation of the alarm at security checkpoints after 153Sm-EDTMP therapy has not been previously reported. Two out of 15 patients who received 153Sm-EDTMP at Roger Maris Cancer Center (Fargo, N. Dak., USA activated the radiation activity sensors while passing through checkpoints; one at a US airport and the other while crossing theAmerican-Canadian border. We assume that the 154Eu which remained in the patients’ bones activated the sensors. Methods: In order to investigate this hypothesis, we obtained the consent from 3 of our 15 patients who received 153Sm-EDTMP within the previous 4 months to 2 years, including the patient who had activated the radiation alarm at the airport. The patients were scanned with a handheld detector and a gamma camera for energies from 511 keV to 1.3 MeV. Results: All three patients exhibited identical spectral images, and further analysis showed that the observed spectra are the result of 154Eu emissions. Conclusion: Depending on the detection thresholds and windows used by local and federal authorities, the remaining activity of 154Eu retained in patients who received 153Sm-EDTMP could be sufficient enough to increase the count rates above background levels and activate the sensors. At Roger Maris Cancer Center, patients are now informed of the potential consequences of 153Sm-EDTMP therapy prior to initiating treatment. In addition, patients treated with 153Sm-EDTMP at Roger Maris Cancer Center

  11. The Level of Europium-154 Contaminating Samarium-153-EDTMP Activates the Radiation Alarm System at the US Homeland Security Checkpoints.

    Science.gov (United States)

    Najeeb Al Hallak, Mohammed; McCurdy, Matt; Zouain, Nicolas; Hayes, Justin

    2009-08-28

    (153)Sm-EDTMP is a radiopharmaceutical composed of EDTMP (ethylenediamine-tetramethylenephosphonate) and Samarium-153 [1]. (153)Sm-EDTMP has an affinity for skeletal tissue and concentrates in areas with increased bone turnover; thus, it is successfully used in relieving pain related to diffuse bone metastases [1]. The manufacturing process of (153)Sm-EDTMP leads to contamination with (154)Eu (Europium-154) [2]. A previous study only alluded to the retention of (154)Eu in the bones after receiving treatment with (153)Sm-EDTMP [2]. Activation of the alarm at security checkpoints after (153)Sm-EDTMP therapy has not been previously reported. Two out of 15 patients who received (153)Sm-EDTMP at Roger Maris Cancer Center (Fargo, N. Dak., USA) activated the radiation activity sensors while passing through checkpoints; one at a US airport and the other while crossing the American-Canadian border. We assume that the (154)Eu which remained in the patients' bones activated the sensors. METHODS: In order to investigate this hypothesis, we obtained the consent from 3 of our 15 patients who received (153)Sm-EDTMP within the previous 4 months to 2 years, including the patient who had activated the radiation alarm at the airport. The patients were scanned with a handheld detector and a gamma camera for energies from 511 keV to 1.3 MeV. RESULTS: All three patients exhibited identical spectral images, and further analysis showed that the observed spectra are the result of (154)Eu emissions. CONCLUSION: Depending on the detection thresholds and windows used by local and federal authorities, the remaining activity of (154)Eu retained in patients who received (153)Sm-EDTMP could be sufficient enough to increase the count rates above background levels and activate the sensors. At Roger Maris Cancer Center, patients are now informed of the potential consequences of (153)Sm-EDTMP therapy prior to initiating treatment. In addition, patients treated with (153)Sm-EDTMP at Roger Maris Cancer

  12. Low-cost industrially available molybdenum boride and carbide as "platinum-like" catalysts for the hydrogen evolution reaction in biphasic liquid systems.

    Science.gov (United States)

    Scanlon, Micheál D; Bian, Xiaojun; Vrubel, Heron; Amstutz, Véronique; Schenk, Kurt; Hu, Xile; Liu, BaoHong; Girault, Hubert H

    2013-02-28

    Rarely reported low-cost molybdenum boride and carbide microparticles, both of which are available in abundant quantities due to their widespread use in industry, adsorb at aqueous acid-1,2-dichloroethane interfaces and efficiently catalyse the hydrogen evolution reaction in the presence of the organic electron donor - decamethylferrocene. Kinetic studies monitoring biphasic reactions by UV/vis spectroscopy, and further evidence provided by gas chromatography, highlight (a) their superior rates of catalysis relative to other industrially significant transition metal carbides and silicides, as well as a main group refractory compound, and (b) their highly comparable rates of catalysis to Pt microparticles of similar dimensions. Insight into the catalytic processes occurring for each adsorbed microparticle was obtained by voltammetry at the liquid-liquid interface.

  13. X-Ray photoelectron spectroscopy study of radiofrequency-sputtered titanium, carbide, molybdenum carbide, and titanium boride coatings and their friction properties

    Science.gov (United States)

    Brainard, W. A.; Wheeler, D. R.

    1977-01-01

    Radiofrequency sputtered coatings of titanium carbide, molybdenum carbide and titanium boride were tested as wear resistant coatings on stainless steel in a pin on disk apparatus. X-ray photoelectron spectroscopy (XPS) was used to analyze the sputtered films with regard to both bulk and interface composition in order to obtain maximum film performance. Significant improvements in friction behavior were obtained when properly biased films were deposited on deliberately preoxidized substrates. XPS depth profile data showed thick graded interfaces for bias deposited films even when adherence was poor. The addition of 10 percent hydrogen to the sputtering gas produced coatings with thin poorly adherent interfaces. Results suggest that some of the common practices in the field of sputtering may be detrimental to achieving maximum adherence and optimum composition for these refractory compounds.

  14. The coloring problem in the solid-state metal boride carbide ScB{sub 2}C{sub 2}. A theoretical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lassoued, Souheila [Universite de Rennes, Ecole Nationale Superieure de Chimie, UMR 6226 CNRS (France). Inst. des Sciences Chimiques; Universite Kasdi Merbah-Ouargla (Algeria). Faculte des Mathematiques et des Sciences de la Matiere; Boucher, Benoit [Universite de Rennes, Ecole Nationale Superieure de Chimie, UMR 6226 CNRS (France). Inst. des Sciences Chimiques; Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany); Boutarfaia, Ahmed [Universite Kasdi Merbah-Ouargla (Algeria). Faculte des Mathematiques et des Sciences de la Matiere; Gautier, Regis; Halet, Jean-Francois [Universite de Rennes, Ecole Nationale Superieure de Chimie, UMR 6226 CNRS (France). Inst. des Sciences Chimiques

    2016-08-01

    The electronic properties of the layered ternary metal boride carbide ScB{sub 2}C{sub 2}, the structure of which consists of B/C layers made of fused five- and seven-membered rings alternating with scandium sheets, are analyzed. In particular, the respective positions of the B and C atoms (the so-called coloring problem) are tackled using density functional theory, quantum theory of atoms in molecules, and electron localizability indicator calculations. Results reveal that (i) the most stable coloring minimizes the number of B-B and C-C contacts and maximizes the number of boron atoms in the heptagons, (ii) the compound is metallic in character, and (iii) rather important covalent bonding occurs between the metallic sheets and the boron-carbon network.

  15. Synthesis, boron-nonstoichiometry and hardness of perovskite-type rare earth rhodium borides RRh{sub 3}B {sub x} (R = La, Gd, Lu and Sc)

    Energy Technology Data Exchange (ETDEWEB)

    Shishido, T. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)]. E-mail: shishido@imr.tohoku.ac.jp; Ye, J. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Okada, S. [Faculty of Engineering, Kokushikan University, 4-28-1 Setagaya-ku, Tokyo 154-8515 (Japan); Kudou, K. [Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan); Iizumi, K. [Faculty of Engineering, Tokyo Institute of Polytechnics, 1583 Iiyama, Atsugi 243-0297 (Japan); Oku, M. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Ishizawa, Y. [Department of Environmental Science, Iwaki Meisei University, 5-5-1 Iino, Chuohdai, Iwaki 970-8551 (Japan); Sahara, R.; Kumar, V. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yoshikawa, A. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Tanaka, M. [Photon Factory, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba 305-0801 (Japan); Horiuchi, H. [Earth Science Laboratory, Faculty of Education, Hirosaki University, 1 Bunkyo-cho, Hirosaki 036-8560 (Japan); Nomura, A.; Sugawara, T.; Obara, K. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Amano, T. [Shonan Institute of Technology, 1-1-25, Tsujido-Nishikaigan, Fujisawa 251-8511 (Japan); Kohiki, S. [Department of Materials Science, Kyusyu Institute of Technology, Kita-Kyusyu 804-8550 (Japan); Kawazoe, Y.; Nakajima, K. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2006-02-09

    Rare earth ternary borides, RRh{sub 3}B {sub x} (R = La, Gd, Lu and Sc) have been synthesized by arc melting method. Borides RRh{sub 3}B {sub x} (R = La, Gd, Lu and Sc) have perovskite-type cubic structure: space group Pm3m; Z = 1. The lattice parameters a of the stoichiometric RRh{sub 3}B for R = La, Gd, Lu and Sc are 0.4251(1), 0.4183(1), 0.4126(1) and 0.4080(1) nm, respectively. LaRh{sub 3}B {sub x} does not have boron-nonstoichiometry as x = 0. In GdRh{sub 3}B {sub x} and LuRh{sub 3}B {sub x}, boron- nonstoichiometry ranges between 0.55 {<=} x {<=} 1 and 0.30 {<=} x {<=} 1, respectively. The boron-nonstoichiometry range is the widest, 0 {<=} x {<=} 1, for R = Sc. Boron-nonstoichiometry increases with decreasing atomic radius of R. The microhardness of the stoichiometric RRh{sub 3}B for R = La, Gd, Lu and Sc is 4.2 {+-} 0.1, 6.8 {+-} 0.1, 7.7 {+-} 0.5 and 9.9 {+-} 0.1 GPa, respectively. As a result, microhardness increases with decreasing atomic size of R in RRh{sub 3}B; R is positioned at the eight corners of the cube in the perovskite-type structure. Thus, hardness is strongly dependent on R element. The hardness changes almost linearly with boron concentration x for R = Gd and Lu in RRh{sub 3}B {sub x}, while no linear dependency is found for R = Sc. Ab initio calculations have been performed to obtain the equilibrium lattice constants and the bulk moduli. The calculated lattice constants are in excellent agreement with experimental results.

  16. Formation of a new adduct based on fullerene tris-malonate samarium salt C60-[C60(=C(COO)2)3]Sm2

    Science.gov (United States)

    Petrov, A. A.; Keskinov, V. A.; Semenov, K. N.; Charykov, N. A.; Letenko, D. G.; Nikitin, V. A.

    2017-03-01

    Gram quantities of a new adduct based on light fullerene tris-malonate samarium salt C60 [C60(=C(COO)2)3]Sm2 are obtained via the reaction of ion exchange. The obtained adduct is studied by means of electron and infrared spectroscopy, X-ray and elemental analysis, electron microscopy, and thermogravimetry. The polythermal solubility of [C60(=C(COO)2)3]Sm2 in water is determined in ampoules via saturation within 20-70°C. The composition of crystalline hydrate [C60(=C(COO)2)3]Sm2 · 36H2O, which exists in equilibrium with the saturated solution, is estimated.

  17. Biodistribution of samarium-153-EDTMP in rats treated with docetaxel Biodistribuição de EDTMP-153-samário em ratos tratados com docetaxel

    Directory of Open Access Journals (Sweden)

    Arthur Villarim Neto

    2009-02-01

    Full Text Available PURPOSE: Many patients with metastatic bone disease have to use radiopharmaceuticals associated with chemotherapy to relieve bone pain. The aim of this study was to assess the influence of docetaxel on the biodistribution of samarium-153-EDTMP in bones and other organs of rats. METHODS: Wistar male rats were randomly allocated into 2 groups of 6 rats each. The DS (docetaxel/samarium group received docetaxel (15 mg/kg intraperitoneally in two cycles 11 days apart. The S (samarium/control group rats were not treated with docetaxel. Nine days after chemotherapy, all the rats were injected with 0.1ml of samarium-153-EDTMP via orbital plexus (25µCi. After 2 hours, the animals were killed and samples of the brain, thyroid, lung, heart, stomach, colon, liver, kidney and both femurs were removed. The percentage radioactivity of each sample (% ATI/g was determined in an automatic gamma-counter (Wizard-1470, Perkin-Elmer, Finland. RESULTS: On the 9th day after the administration of the 2nd chemotherapy cycle, the rats had a significant weight loss (314.50±22.09g compared (pOBJETIVO: Muitos pacientes com metástases ósseas são tratados com radiofármacos associados com quimioterapia para alívio da dor óssea. O objetivo do trabalho foi estudar a influência do docetaxel na biodistribuição do EDTMP-153-samário nos ossos e outros órgãos de ratos. MÉTODOS: Ratos Wistar foram aleatoriamente alocados em 2 grupos de 6 animais cada. O grupo DS (docetaxel/samário recebeu docetaxel (15 mg/kg intraperitoneal em dois ciclos com 11 dias de intervalo. Os ratos do grupo S (samário/controle não foram tratados com docetaxel. Nove dias após a quimioterapia, todos os animais receberam 0,1ml de EDTMP-153-samário via plexo orbital (25µCi. Após 2 horas, os animais foram mortos e feitas biópsias de cérebro, tireóide, pulmão, coração, estômago, cólon, fígado, rim e fêmures. O percentual de radioatividade por grama (%ATI/g de tecido de cada bi

  18. Marrow irradiation with high-dose 153Samarium-EDTMP followed by chemotherapy and hematopoietic stem cell infusion for acute myelogenous leukemia.

    Science.gov (United States)

    Rodriguez, Vilmarie; Anderson, Peter M; Litzow, Mark R; Erlandson, Linda; Trotz, Barbara A; Arndt, Carola A S; Khan, Shakila P; Wiseman, Gregory A

    2006-08-01

    In four patients, aged 15 - 20 years, with high-risk acute myeloid leukemia (AML), high-dose samarium 153-labelled ethylenediaminetetramethylenephosphonate (153Sm-EDTMP) was used for targeted marrow irradiation before preparative chemotherapy conditioning regimens and allogeneic (three patients) or autologous (one patient) hematopoietic stem cell transplantation. The dose of 153Sm-EDTMP was 703 MBq/kg (n = 1) or 1110 MBq/kg (n = 3). No side-effects occurred during the 30-min infusion of 153Sm-EDTMP. Samarium - melphalan regimens were given to three patients; one had 153Sm-EDTMP - busulfan + cyclophosphamide. Total body radioactivity was below the 133 MBq safe limit before infusion of stem cells (day 14 after 153Sm-EDTMP). No hemorrhagic cystitis, nephrotoxicity or serious infections occurred. Leukocyte engraftment (white blood cell count >0.5 x 10(9)/l) occurred between 12 and 23 days after stem cell infusion (mean of 17 days). Complete cytogenetic and morphologic remission of AML was evident on follow-up marrow aspirate and biopsy specimens from all patients. In two of the four study patients, the disease remains in complete remission and the patients have an excellent quality of life (Eastern Cooperative Oncology Group performance status 0; no medications) and no organ toxicity more than 2 years and more than 4 years, respectively, after their blood and bone marrow transplantations. Thus, in adolescents and adults, 153Sm-EDTMP may provide a relatively simple and effective means for using irradiation to eliminate AML within the marrow.

  19. A Study on the Effect of the Boron Potential on the Mechanical Properties of the Borided Layers Obtained by Boron Diffusion at the Surface of AISI 316L Steel

    Directory of Open Access Journals (Sweden)

    E. Hernández-Sánchez

    2014-01-01

    Full Text Available The effect of the boron potential on the thickness and the mechanical properties of borided layers was evaluated. The boron potential was established by means of the available atoms of boron contained in a control volume inside a cylinder. The cylinders were manufactured from AISI 316L steel, and the boriding treatment was performed using the powder pack technique at a temperature of 1273 K over an exposure time of 6 h. Four different internal diameters of the cylinders were evaluated (3.17, 4.76, 6.35, and 7.93 mm. The mechanical properties were evaluated using the Berkovich instrumented indentation technique. The results showed a clear influence of the boron potential on the mechanical properties of the layers. The hardness of the layers was stablished in the range of 16.22 to 21.16 GPa. Young’s modulus values were stablished in the range of 255.96 to 341.37 GPa. Also the fracture toughness and brittleness of the layers reflected the influence of the boron potential supplied during the boriding process. Finally, the influence of the boron potential on the constant of parabolic growth (K was also established as a function of the inner diameter of the cylinders.

  20. Synthesis of samarium complexes with the derivative binder of Schiff Quinolinic base. Characterization and photophysical study; Sintesis de complejos de samario con el ligante derivado de base de Schiff Quinolinica. Caracterizacion y estudio fotofisico

    Energy Technology Data Exchange (ETDEWEB)

    Lucas H, J.

    2016-07-01

    In this work we determined the metal: binder stoichiometry of the species formed during the UV/Vis spectrophotometric titration of the derivative binder of Schiff quinolinic base, L1 with the samarium nitrate pentahydrate in methanol. Statistical analysis of the data allowed proposing the metal: binder stoichiometry for the synthesis of the complexes which was one mole of samarium salt by 2.5 moles of binder and thus favor the formation of complexes with 1M: 1L and 1M: 2L stoichiometries. They were synthesized in aqueous-organic medium (water-ethanol), isolated and purified two complexes with stoichiometry 1 Sm: 1 L1, complex 1 and 1 Sm: 2 L1, complex 2. The overall yield of the reaction was 76%. The characterization of the formed complexes was performed by visible ultraviolet spectrometry (UV/Vis), nuclear magnetic resonance, X-ray photoelectron spectroscopy (XP S), thermal gravimetric analysis with differential scanning calorimetry (TGA/DSC), and radial distribution function. These complexes were studied by fluorescence and emission phosphorescence at variable temperature. Spectroscopic techniques used in both solution and solid demonstrated the formation and stability of these complexes. In addition XP S indicated that in both complexes the samarium retains its oxidation state 3+. Luminescence studies indicated that there is intra-binding charge transfer which decreases the transfer of light energy from the binder to the samarium. Based on the experimental results, L1 binder molecules and complexes 1 and 2 were modeled that demonstrated the proposed Nc for each complex, as well as allowed to visualize the structural arrangement of the molecules, complexes and binder. (Author)

  1. New ternary tantalum borides containing boron dumbbells: Experimental and theoretical studies of Ta{sub 2}OsB{sub 2} and TaRuB

    Energy Technology Data Exchange (ETDEWEB)

    Mbarki, Mohammed; Touzani, Rachid St.; Rehorn, Christian W.G.; Gladisch, Fabian C. [Institute of Inorganic Chemistry, RWTH Aachen University, D-52056 Aachen (Germany); Fokwa, Boniface P.T., E-mail: bfokwa@ucr.edu [Institute of Inorganic Chemistry, RWTH Aachen University, D-52056 Aachen (Germany); Department of Chemistry, University of California Riverside (UCR), Riverside, CA 92521 (United States)

    2016-10-15

    The new ternary transition metal-rich borides Ta{sub 2}OsB{sub 2} and TaRuB have been successfully synthesized by arc-melting the elements in a water-cooled crucible under an argon atmosphere. The crystal structures of both compounds were solved by single-crystal X-ray diffraction and their metal compositions were confirmed by EDX analysis. It was found that Ta{sub 2}OsB{sub 2} and TaRuB crystallize in the tetragonal Nb{sub 2}OsB{sub 2} (space group P4/mnc, no. 128) and the orthorhombic NbRuB (space group Pmma, no. 51) structure types with lattice parameters a=5.878(2) Å, c=6.857(2) Å and a=10.806(2) Å, b=3.196(1) Å, c=6.312(2) Å, respectively. Furthermore, crystallographic, electronic and bonding characteristics have been studied by density functional theory (DFT). Electronic structure relaxation has confirmed the crystallographic parameters while COHP bonding analysis indicates that B{sub 2}-dummbells are the strongest bonds in both compounds. Moreover, the formation of osmium dumbbells in Ta{sub 2}OsB{sub 2} through a Peierls distortion along the c-axis, is found to be the origin of superstructure formation. Magnetic susceptibility measurements reveal that the two phases are Pauli paramagnets, thus confirming the theoretical DOS prediction of metallic character. Also hints of superconductivity are found in the two phases, however lack of single phase samples has prevented confirmation. Furthermore, the thermodynamic stability of the two modifications of AMB (A=Nb, Ta; M =Ru, Os) are studied using DFT, as new possible phases containing either B{sub 4}- or B{sub 2}-units are predicted, the former being the most thermodynamically stable modification. - Graphical abstract: The two new ternary tantalum borides, Ta{sub 2}OsB{sub 2} and TaRuB, have been discovered. Their crystal structures contain boron dumbbells, which are the strongest bonds. Peirls distortion is found responsible for Os{sub 2}-dumbbells formation in Ta{sub 2}OsB{sub 2}. Ta{sub 2}OsB{sub 2} and

  2. Effect of Heat Treatment on Borides Precipitation and Mechanical Properties of CoCrFeNiAl1.8Cu0.7B0.3Si0.1 High-Entropy Alloy Prepared by Arc-Melting and Laser-Cladding

    Science.gov (United States)

    Zhang, H.; Tang, H.; He, Y. Z.; Zhang, J. L.; Li, W. H.; Guo, S.

    2017-11-01

    Effects of heat treatment on borides precipitation and mechanical properties of arc-melted and laser-cladded CoCrNiFeAl1.8Cu0.7B0.3Si0.1 high-entropy alloys were comparatively studied. The arc-melted alloy contains lots of long strip borides distributed in the body-centered cubic phase, with a hardness about 643 HV0.5. Laser-cladding can effectively inhibit the boride precipitation and the laser-cladded alloy is mainly composed of a simple bcc solid solution, with a high hardness about 769 HV0.5, indicating the strengthening effect by interstitial boron atoms is greater than the strengthening by borides precipitation. Heat treatments between 800°C and 1200°C can simultaneously improve the hardness and fracture toughness of arc-melted alloys, owing to the boride spheroidization, dissolution, re-precipitation, and hence the increased boron solubility and nano-precipitation in the bcc solid solution. By contrast, the hardness of laser-cladded alloys reduce after heat treatments in the same temperature range, due to the decreased boron solubility in the matrix.

  3. Pyrolysis result of polyethylene waste as fuel for solid oxide fuel cell with samarium doped-ceria (SDC)-carbonate as electrolyte

    Science.gov (United States)

    Syahputra, R. J. E.; Rahmawati, F.; Prameswari, A. P.; Saktian, R.

    2017-02-01

    In this research, the result of pyrolysis on polyethylene was used as fuel for a solid oxide fuel cell (SOFC). The pyrolysis result is a liquid which consists of hydrocarbon chains. According to GC-MS analysis, the hydrocarbons mainly consist of C7 to C20 hydrocarbon chain. Then, the liquid was applied to a single cell of NSDC-L | NSDC | NSDC-L. NSDC is a composite SDC (samarium doped-ceria) with sodium carbonate. Meanwhile, NSDC-L is a composite of NSDC with LiNiCuO (LNC). NSDC and LNC were analyzed by X-ray diffraction to understand their crystal structure. The result shows that presence of carbonate did not change the crystal structure of SDC. SEM EDX analysis for fuel cell before and after being loaded with polyethylene oil to get information of element diffusion to the electrolyte. Meanwhile, the conductivity properties were investigated through impedance measurement. The presence of carbonate even increases the electrical conductivity. The single cell test with the pyrolysis result of polyethylene at 300 - 600 °C, found that the highest power density is at 600 °C with the maximum power density of 0.14 mW/cm2 and open circuit voltage of 0.4 Volt. Elemental analysis at three point spots of single cell NDSC-L |NSDC|NSDC-L found that a migration of ions was occurred during fuel operation at 300 - 600 °C.

  4. Effects of some rare earth and carbonate-based co-dopants on structural and electrical properties of samarium doped ceria (SDC) electrolytes for solid oxide fuel cells

    Science.gov (United States)

    Anwar, Mustafa; Khan, Zuhair S.; Mustafa, Kamal; Rana, Akmal

    2015-09-01

    In the present study, samarium doped ceria (SDC) and SDC-based composite with the addition of K2CO3 were prepared by co-precipitation route and effects of pH of the solution and calcination temperature on microstructure of SDC and SDC-K2CO3, respectively, were investigated. Furthermore, experimentation was performed to investigate into the ionic conductivity of pure SDC by co-doping with yttrium i.e., YSDC, XRD and SEM studies show that the crystallite size and particle size of SDC increases with the increase in pH. The SEM images of all the samples of SDC synthesized at different pH values showed the irregular shaped and dispersed particles. SDC-K2CO3 was calcined at 600∘C, 700∘C and 800∘C for 4 h and XRD results showed that crystallite size increases while lattice strain, decreases with the increase in calcination temperature and no peaks were detected for K2CO3 as it is present in an amorphous form. The ionic conductivity of the electrolytes increases with the increase in temperature and SDC-K2CO3 shows the highest value of ionic conductivity as compared to SDC and YSDC. Chemical compatibility tests were performed between the co-doped electrolyte and lithiated NiO cathode at high temperature. It revealed that the couple could be used up to the temperature of 700∘C.

  5. Calculation of the Dose of Samarium-153-Ethylene Diamine Tetramethylene Phosphonate (153Sm-EDTMP as a Radiopharmaceutical for Pain Relief of bone Metastasis

    Directory of Open Access Journals (Sweden)

    Fatemeh Razghandi

    2016-04-01

    Full Text Available Introduction One of the important applications of nuclear physics in medicine is the use of radioactive elements as radiopharmaceuticals. Metastatic bone disease is the most common form of malignant bone tumors. Samarium-153-ethylene diamine tetramethylene phosphonate (153Sm-EDTMP as a radiopharmaceutical is used for pain palliation. This radiopharmaceutical usually emits beta particles, which have a high uptake in bone tissues. The purpose of this study was to calculate the radiation dose distribution of 153Sm-EDTMP in bone and other tissues, using MCNPX Monte Carlo code in the particle transport model. Materials and Methods Dose delivery to the bone was simulated by seeking radiopharmaceuticals on the bone surface. The phantom model had a simple cylindrical geometry and included bone, bone marrow, and soft tissue. Results The simulation results showed that a significant amount of radiation dose was delivered to the bone by the use of this radiopharmaceutical. Conclusion Thebone acted as a fine protective shield against rays for the bone marrow. Therefore, the trivial absorbed dose by the bone marrow caused less damage to bone-making cells. Also, the high absorbed dose of the bone could destroy cancer cells and relieve the pain in the bone.

  6. Synthesis, quality control and biological evaluation of tris[(1,10-phenanthroline)[{sup 153}Sm]samarium(III)]trithiocyanate complex as a therapeutic agent

    Energy Technology Data Exchange (ETDEWEB)

    Naseri, Z.; Kharat, A. Nemati [Tehran Univ. (Iran, Islamic Republic of). Inorganic Chemistry Dept.; Hakimi, A. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Nuclear Engineering, Science and Research Branch; Jalilian, A.R.; Shirvani-Arani, S.; Bahrami-Samani, A.; Ghannadi-Maragheh, M. [Nuclear Science and Technology Research Institute (NSTRI), Tehran (IR). Radiopharmaceutical Research and Development Lab (RRDL)

    2012-07-01

    Therapeutic radiopharmaceuticals are designed to deliver high doses of radiation to selected target organs or tissues with an aim of minimizing unwanted radiation to surrounding healthy tissue. In this work, [tris(1,10-phenanthroline)[{sup 153}Sm]samarium(III)]trithiocyanate ({sup 153}Sm-TPTTC) was developed for possible therapeutic properties. The cold compound, i.e. {sup nat}Sm-TPTTC was prepared and characterized by IR, UV, mass and {sup 1}H-NMR spectroscopy. {sup 153}Sm-TPTTC was prepared in two steps using [{sup 153}Sm]SmCl{sub 3}, obtained by neutron activation of an enriched {sup 152}Sm sample. Stability tests, partition coefficient determination, toxicity tests and biodistribution studies of the complex in wild-type and fibrosarcoma-bearing mice were determined. The radiolabeled complex was prepared in high radiochemical purity (> 99% precipitation method) and specific activity of 278 GBq/mmol and demonstrated significant stability at 4, 25 and 37 C (in presence of human serum). Initial complex biodistribution data showed significant liver accumulation in wild-type mice and significant tumor accumulation in fibrosarcoma-bearing mice with tumor:blood and tumor:muscle ratios of 3.55 (2 h) and 38.26 (96 h) respectively. {sup 153}Sm-TPTTC properties suggest an efficient tumor targeting agent with high tumor-avidity. Further investigation on the therapeutic properties must be conducted. (orig.)

  7. Caracterización de la capa de boruros formada durante la austenización de un hierro nodular austemperizado//Characterization of borides coating formed during austenitization of an austempered ductile iron

    Directory of Open Access Journals (Sweden)

    Urbano Ordóñez‐Hernández

    2015-01-01

    Full Text Available En este trabajo se ha investigado el efecto de la austenitización y el borurado simultáneos, a 950 ºC, en la microestructura, la microdureza Vickers y el espesor de la capa borurada en medio líquido de un hierro nodular austemperizado no aleado. Se demostró que es posible obtener una capa de boruros de hierro muy bien estructurada con la microdureza Vickers suficientemente alta (1400 HVy con adecuado espesor de capa de 67 μm, sobre un sustrato de ausferrita típico de las fundiciones nodulares austemperizadas. Por medio de un ensayo pin on disc modificado, se comprobó la superior resistencia al desgaste abrasivo de la capa de boruros depositada durante la austenización del ADI, comparada con la máxima obtenida durante el austempering de éste sin aplicar el recubrimiento.Palabras claves: hierro nodular, borurado, austenización, austemperizado.______________________________________________________________________________AbstractThe effect of simultaneous austenitization and boriding at 950 ºC, on microstructure, Vickers hardness and boronized layer thickness of a non alloyed austempered ductile iron has been investigated. It was demonstrated that it is possible to obtain a well formed boronized layer with a Vicker hardness sufficiently high (1400 HV, and with an appropriated 67μm layer thickness, on a typical ausferrite ADI substrate. By using a modified pin on disc test, it was demonstrated the higher abrasion wear resistance of borides layer deposited during ADI austenitization process, compared with Vickers hardness of low temperature noncoated austempered ductile iron.Key words: ductile iron, boriding, austenitization, austempering.

  8. Comportamiento parabólico del crecimiento de capas boradas en los aceros Y8A y X12M // Parabolic behavior of boriding layers growth in Y8A and X12M steels

    Directory of Open Access Journals (Sweden)

    C. Figueroa Hernández

    1999-01-01

    Full Text Available Se determina la influencia que tienen los principales parámetros tecnológicos del borado en el crecimiento de las capas y secorrobora el cumplimiento de la ley parabólica para predecir este comportamiento en los aceros Y8A y X12M.El proceso de borado se aplica en una mezcla de carburo de silicio y bórax (70 y 30 % a la temperatura de 850, 900 y 950 oCdurante un tiempo de 2, 4 y 6 horas. Como variable dependiente se seleccionó la profundidad del recubrimiento, a partir de lacual se obtuvieron los coeficientes del crecimiento parabólico y la energía de activación en función de la temperatura, el tiempodel proceso y el tipo de acero.La caracterización metalográfica reveló la presencia de la fase Fe2BPalabras claves: Borado, recubrimiento superf icial , t ecnología de recubrimiento.__________________________________________________________________________AbstractIt was determined the influence of the main technological parameters of the boriding process, and a mathematical model thatallows to predict this conduct on the steels Y8A and X12M steels was obtained.The boriding process is applied in a mixture of silicon carbide and borax (70 and 30% at 850, 900 and 950 oC temperatureduring a period of time 2, 4 and 6 hours. As an independent variable the depth of the coat was selected.It was obtained the parabolic growth coefficients, and the activation energy according to temperature, time and the chemicalcomposition of steel.Metallografic analysis reveals the presence of Fe2B phase.Key words: Boriding process, superf icial coat , coat technology.

  9. History of ``NANO''-Scale VERY EARLY Solid-State (and Liquid-State) Physics/Chemistry/Metallurgy/ Ceramics; Interstitial-Alloys Carbides/Nitrides/Borides/...Powders and Cermets, Rock Shocks, ...

    Science.gov (United States)

    Maiden, Colin; Siegel, Edward

    History of ``NANO'': Siegel-Matsubara-Vest-Gregson[Mtls. Sci. and Eng. 8, 6, 323(`71); Physica Status Solidi (a)11,45(`72)] VERY EARLY carbides/nitrides/borides powders/cermets solid-state physics/chemistry/metallurgy/ ceramics FIRST-EVER EXPERIMENTAL NANO-physics/chemistry[1968 ->Physica Status Solidi (a)11,45(`72); and EARLY NANO-``physics''/NANO-``chemistry'' THEORY(after: Kubo(`62)-Matsubara(`60s-`70s)-Fulde (`65) [ref.: Sugano[Microcluster-Physics, Springer('82 `98)

  10. Synthesis, characterization and thermoelectric properties of metal borides, boron carbides and carbaborides; Synthese, Charakterisierung und thermoelektrische Eigenschaften ausgewaehlter Metallboride, Borcarbide und Carbaboride

    Energy Technology Data Exchange (ETDEWEB)

    Guersoy, Murat

    2015-07-06

    This work reports on the solid state synthesis and structural and thermoelectrical characterization of hexaborides (CaB{sub 6}, SrB{sub 6}, BaB{sub 6}, EuB{sub 6}), diboride dicarbides (CeB{sub 2}C{sub 2}, LaB{sub 2}C{sub 2}), a carbaboride (NaB{sub 5}C) and composites of boron carbide. The characterization was performed by X-ray diffraction methods and Rietveld refinements based on structure models from literature. Most of the compounds were densified by spark plasma sintering at 100 MPa. As high-temperature thermoelectric properties the Seebeck coefficients, electrical conductivities, thermal diffusivities and heat capacities were measured between room temperature and 1073 K. ZT values as high as 0.5 at 1273 K were obtained for n-type conducting EuB{sub 6}. High-temperature X-ray diffraction also confirmed its thermal stability. The solid solutions Ca{sub x}Sr{sub 1-x}B{sub 6}, Ca{sub x}Ba{sub 1-x}B{sub 6} and Sr{sub x}Ba{sub 1-x}B{sub 6} (x = 0, 0.25, 0.5, 0.75, 1) are also n-type but did not show better ZT values for the ternary compounds compared to the binaries, but for CaB{sub 6} the values of the figure of merit (ca. 0.3 at 1073 K) were significantly increased (ca. 50 %) compared to earlier investigations which is attributed to the densification process. Sodium carbaboride, NaB{sub 5}C, was found to be the first p-type thermoelectric material that crystallizes with the hexaboride-structure type. Seebeck coefficients of ca. 80 μV . K{sup -1} were obtained. Cerium diboride dicarbide, CeB{sub 2}C{sub 2}, and lanthanum diboride dicarbide, LaB{sub 2}C{sub 2}, are metallic. Both compounds were used as model compounds to develop compacting strategies for such layered borides. Densities obtained at 50 MPa were determined to be higher than 90 %. A new synthesis route using single source precursors that contain boron and carbon was developed to open the access to new metal-doped boron carbides. It was possible to obtain boron carbide, but metal-doping could not be

  11. Synthesis and characterization of new metal-rich borides with boron fragments; Synthese und Charakterisierung von neuartigen metallreichen Boriden mit Borfragmenten

    Energy Technology Data Exchange (ETDEWEB)

    Mbarki, Mohammed

    2016-03-30

    The present dissertation deals with the synthesis and characterization of new metal-rich borides of the Ce{sub 7}Ni{sub 5±x}Ge{sub 3±x}In{sub 6{sup -}}, Nb{sub 2}OsB{sub 2{sup -}} and NbRuB-type.The samples are synthesized by a solid state reaction route from elements using an electric arc furnace. The structural characterization of the compounds was carried out by using X-ray diffraction methods on powder samples and single crystals. The chemical composition of single-crystals was verified by EDX analyses. Moreover, the magnetic properties of suitable samples were investigated by SQUID magnetometry.The crystal structure of compounds with the nominal composition NbFe{sub 1-x}Ir{sub 6+x}B{sub 8} is successfully solved from single crystal X-ray data. The most prominent feature in this structure are one-dimensional chains along the c-axis formed by the magnetically active element iron on a site of mixed occupation with Iridium (Fe: Ir = 0.77 (2) 0.23 (2)). Thermomagnetic investigations reveal, that ferromagnetic ordering is observed below the Curie temperature (TC) of 350 K. Theoretical investigations suggest that the iron-chains are mainly responsible for the ferromagnetic ordering. In addition, the magnetocaloric effect (MCE) is calculated using isothermal magnetization measurements at several temperatures. The maximal magnetic entropy change ΔS = 0.032 J kg{sup -1} K{sup -1} is observed in the vicinity of T{sub C}. For the phases Nb{sub 6}Mn{sub 0,75(2)}Ir{sub 6,25(2)}B{sub 8} and Nb{sub 6}Co{sub 1,09(2)}Ir{sub 5,91(2)}B{sub 8} a relationship between the measured ferrimagnetic ordering and the crystal structure is found. Tiny superstructure reflections measured by Selected Area Electron Diffraction (SEAD) indicate a different crystal system for those compounds, which allows a ferrimagnetic spin arrangement within this crystal structure.In the second part of the thesis new results about the Nb{sub 2}OsB{sub 2-} and NbRuB-type borides are presented, which both

  12. The studies on complex formation of metal borides in the reaction system of epoxidation of 1-octene with tert-butyl hydroperoxide by IR spectroscopy

    OpenAIRE

    Makota, Oksana; Trach, Yuriy

    2007-01-01

    Вивчено комплексоутворення боридів молібдену і ванадію в реакційній системі епоксидування октену-1 гідропероксидом трет-бутилу методом інфрачервоної спектроскопії. Показано, що октен-1 утворює комплекс з металевою складовою у випадку бориду молібдену і з боридною складовою у випадку бориду ванадію.The complex formation of molybdenum and vanadium borides in the reaction system of 1-octene epoxidation with tert -butyl hydroperoxide by infrared spectroscopic analysis was studied. It was sh...

  13. Retention capacity of samarium (III) in zircon for it possible use in retaining walls for confinement of nuclear residues; Capacidad de retencion de samario (III) en circon para su posible uso en barreras de contencion para confinamiento de residuos nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N

    2006-07-01

    Mexico, as country that produces part of its electric power by nuclear means, should put special emphasis in the development of technologies guided to the sure and long term confinement of the high level nuclear residuals. This work studies the capacity that has the natural zircon to retain to the samarium (III) in solution, by what due, firstly, to characterize the zircon for technical instrumental to determine the purity and characteristic of the mineral in study. The instrumental techniques that were used to carry out the physicochemical characterization were the neutron activation analysis (NAA), the infrared spectroscopy (IS), the thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), semiquantitative analysis, dispersive energy spectroscopy (EDS), X-ray diffraction (XRD) and luminescence technique. The characterization of the surface properties carries out by means of the determination of the surface area using the BET multipoint technique, acidity constants, hydration time, the determination of the point of null charge (pH{sub PCN}) and density of surface sites (D{sub s}). The luminescence techniques were useful to determine the optimal point hydration of the zircon and for the quantification of the samarium, for that here intends the development of both analysis techniques. With the adjustment of the titration curves in the FITEQL 4 package the constants of surface acidity in the solid/liquid interface were determined. To the finish of this study it was corroborated that the zircon is a mineral that presents appropriate characteristics to be proposed as a contention barrier for the deep geologic confinement. With regard to the study of adsorption that one carries out the samarium retention it is superior to 90% under the described conditions. This investigation could also be applicable in the confinement of dangerous industrial residuals. (Author)

  14. SU-C-201-06: Utility of Quantitative 3D SPECT/CT Imaging in Patient Specific Internal Dosimetry of 153-Samarium with GATE Monte Carlo Package

    Energy Technology Data Exchange (ETDEWEB)

    Fallahpoor, M; Abbasi, M [Tehran University of Medical Sciences, Vali-Asr Hospital, Tehran, Tehran (Iran, Islamic Republic of); Sen, A [University of Houston, Houston, TX (United States); Parach, A [Shahid Sadoughi University of Medical Sciences, Yazd, Yazd (Iran, Islamic Republic of); Kalantari, F [UT Southwestern Medical Center, Dallas, TX (United States)

    2015-06-15

    Purpose: Patient-specific 3-dimensional (3D) internal dosimetry in targeted radionuclide therapy is essential for efficient treatment. Two major steps to achieve reliable results are: 1) generating quantitative 3D images of radionuclide distribution and attenuation coefficients and 2) using a reliable method for dose calculation based on activity and attenuation map. In this research, internal dosimetry for 153-Samarium (153-Sm) was done by SPECT-CT images coupled GATE Monte Carlo package for internal dosimetry. Methods: A 50 years old woman with bone metastases from breast cancer was prescribed 153-Sm treatment (Gamma: 103keV and beta: 0.81MeV). A SPECT/CT scan was performed with the Siemens Simbia-T scanner. SPECT and CT images were registered using default registration software. SPECT quantification was achieved by compensating for all image degrading factors including body attenuation, Compton scattering and collimator-detector response (CDR). Triple energy window method was used to estimate and eliminate the scattered photons. Iterative ordered-subsets expectation maximization (OSEM) with correction for attenuation and distance-dependent CDR was used for image reconstruction. Bilinear energy mapping is used to convert Hounsfield units in CT image to attenuation map. Organ borders were defined by the itk-SNAP toolkit segmentation on CT image. GATE was then used for internal dose calculation. The Specific Absorbed Fractions (SAFs) and S-values were reported as MIRD schema. Results: The results showed that the largest SAFs and S-values are in osseous organs as expected. S-value for lung is the highest after spine that can be important in 153-Sm therapy. Conclusion: We presented the utility of SPECT-CT images and Monte Carlo for patient-specific dosimetry as a reliable and accurate method. It has several advantages over template-based methods or simplified dose estimation methods. With advent of high speed computers, Monte Carlo can be used for treatment planning

  15. Fabrication of catalytically active nanocrystalline samarium (Sm)-doped cerium oxide (CeO2) thin films using electron beam evaporation

    Science.gov (United States)

    Kundu, Subrata; Sutradhar, Narottam; Thangamuthu, R.; Subramanian, B.; Panda, Asit Baran; Jayachandran, M.

    2012-08-01

    Samarium (Sm)-doped cerium oxide (CeO2) thin films were fabricated using electron beam evaporation technique. The synthesized films were deposited either on glass or ITO substrates and studied their nature by annealing at different temperatures. The optical properties and other morphological studies were done by UV-Vis, XRD, XPS, SEM, EDS, and FT-IR analysis. XRD and XPS analysis clearly confirm the presence of Sm in the ceria site. From the SEM study, it was found that after annealing at high temperature ( 300 or 500 °C), the particles size was reduced due to breakdown of large aggregates of particles which is also confirmed from UV-Vis, XPS, and XRD analyses. The FT-IR study proves the presence of -COO-, -OH, or ammonium group on the particles surface. The deposition of Sm-doped CeO2 nanomaterials was found more feasible on ITO substrate compared to that of glass substrate in terms of stability and depth of film thickness. The Sm-doped CeO2 nanomaterial acts as a re-usable catalyst for the reduction of organic dye molecules in the presence of NaBH4. The catalysis rate was compared by considering the electron transfer process during the reduction. The synthesized Sm-doped CeO2 thin films might find wide variety of applications in various emerging fields like solid oxide fuel cells (SOFCs), oxygen sensor or as catalyst in different types of organic and inorganic catalytic reactions. The fabrication process is very simple, straightforward, less time consuming, and cost effective.

  16. Fabrication of catalytically active nanocrystalline samarium (Sm)-doped cerium oxide (CeO{sub 2}) thin films using electron beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, Subrata, E-mail: skundu@cecri.res.in [Council of Scientific and Industrial Research (CSIR), Electrochemical Materials Science (ECMS) Division, Central Electrochemical Research Institute - CECRI (India); Sutradhar, Narottam [G. B. Marg, Central Salt and Marine Chemical Research Institute - CSIR (India); Thangamuthu, R.; Subramanian, B. [Council of Scientific and Industrial Research (CSIR), Electrochemical Materials Science (ECMS) Division, Central Electrochemical Research Institute - CECRI (India); Panda, Asit Baran [G. B. Marg, Central Salt and Marine Chemical Research Institute (CSIR) (India); Jayachandran, M., E-mail: mjayam54@yahoo.com [Council of Scientific and Industrial Research (CSIR), Electrochemical Materials Science (ECMS) Division, Central Electrochemical Research Institute - CECRI (India)

    2012-08-15

    Samarium (Sm)-doped cerium oxide (CeO{sub 2}) thin films were fabricated using electron beam evaporation technique. The synthesized films were deposited either on glass or ITO substrates and studied their nature by annealing at different temperatures. The optical properties and other morphological studies were done by UV-Vis, XRD, XPS, SEM, EDS, and FT-IR analysis. XRD and XPS analysis clearly confirm the presence of Sm in the ceria site. From the SEM study, it was found that after annealing at high temperature ({approx}300 or 500 Degree-Sign C), the particles size was reduced due to breakdown of large aggregates of particles which is also confirmed from UV-Vis, XPS, and XRD analyses. The FT-IR study proves the presence of -COO-, -OH, or ammonium group on the particles surface. The deposition of Sm-doped CeO{sub 2} nanomaterials was found more feasible on ITO substrate compared to that of glass substrate in terms of stability and depth of film thickness. The Sm-doped CeO{sub 2} nanomaterial acts as a re-usable catalyst for the reduction of organic dye molecules in the presence of NaBH{sub 4}. The catalysis rate was compared by considering the electron transfer process during the reduction. The synthesized Sm-doped CeO{sub 2} thin films might find wide variety of applications in various emerging fields like solid oxide fuel cells (SOFCs), oxygen sensor or as catalyst in different types of organic and inorganic catalytic reactions. The fabrication process is very simple, straightforward, less time consuming, and cost effective.Graphical Abstract.

  17. ScRu2B3 and Sc2RuB6: Borides Featuring a 2D Infinite Boron Clustering.

    Science.gov (United States)

    Salamakha, Leonid P; Sologub, Oksana; Stöger, Berthold; Rogl, Peter Franz; Waas, Monika; Kapustianyk, Volodymyr B; Bauer, Ernst

    2017-09-05

    Two borides, ScRu2B3 and Sc2RuB6, were obtained by argon-arc melting of the elements followed by annealing at 800 °C. ScRu2B3 exhibits a new structure type with the space group Cmcm (a = 3.0195(2) Å, b = 15.4056(8) Å, c = 5.4492(3) Å; single crystal X-ray data; RF(2) = 0.0105). Sc2RuB6 adopts the Y2ReB6-type structure (space group Pbam; a = 8.8545(2) Å, b = 11.1620(3) Å, c = 3.4760(1) Å; single crystal X-ray data; RF(2) = 0.0185). ScRu2B3 displays an unusual intergrowth of CeCo3B2- and AlB2-related slabs; a striking feature is a boat configuration of puckered boron hexagons within infinite graphite like boron layers (6(3) nets). Sc2RuB6 presents two-dimensional planar nets of condensed boron pentagons, hexagons, and heptagons sandwiched between metal layers. In Sc/Y substituted Y2ReB6-type, Y atoms are distributed exclusively inside the boron heptagons. Exploration of the Sc-Ru-B system at 800 °C including binary boundaries employing EPMA and powder X-ray diffraction technique furthermore rules out the existence of previously reported "ScRuB4" but confirms the formation and crystal structure of Sc2Ru5B4. ScRu4B4 forms in cast alloys (LuRu4B4-type structure; space group I41/acd (No. 142), a = 7.3543(2) Å, c = 14.92137(8) Å). Cell parameters and atomic coordinates have been refined for ScRu2B3, Sc2RuB6, and ScRu4B4 in the scope of the generalized gradient approximation. Ab initio electronic structure calculations indicate a moderate electronic density of states at the Fermi level situated near the upper edge of essentially filled d-bands. Electrical resistivity measurements characterize ScRu2B3 and Sc2RuB6 as metals in concord with electronic band structure calculations.

  18. Crystal structure of monoclinic samarium and cubic europium sesquioxides and bound coherent neutron scattering lengths of the isotopes {sup 154}Sm and {sup 153}Eu

    Energy Technology Data Exchange (ETDEWEB)

    Kohlmann, Holger [Leipzig Univ. (Germany). Inst. of Inorganic Chemistry; Hein, Christina; Kautenburger, Ralf [Saarland Univ., Saarbruecken (Germany). Inorganic Solid State Chemistry; Hansen, Thomas C.; Ritter, Clemens [Institut Laue-Langevin, Grenoble (France); Doyle, Stephen [Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany). Inst. for Synchrotron Radiation (ISS)

    2016-11-01

    The crystal structures of monoclinic samarium and cubic europium sesquioxide, Sm{sub 2}O{sub 3} and Eu{sub 2}O{sub 3}, were reinvestigated by powder diffraction methods (laboratory X-ray, synchrotron, neutron). Rietveld analysis yields more precise structural parameters than previously known, especially for oxygen atoms. Interatomic distances d(Sm-O) in Sm{sub 2}O{sub 3} range from 226.3(4) to 275.9(2) pm [average 241.6(3) pm] for the monoclinic B type Sm{sub 2}O{sub 3} [space group C2/m, a = 1418.04(3) pm, b = 362.660(7) pm, c = 885.48(2) pm, β = 100.028(1) ], d(Eu-O) in Eu{sub 2}O{sub 3} from 229.9(2) to 238.8(2) pm for the cubic bixbyite (C) type [space group Ia anti 3, a = 1086.87(1) pm]. Neutron diffraction at 50 K and 2 K did not show any sign for magnetic ordering in Sm{sub 2}O{sub 3}. Isotopically enriched {sup 154}Sm{sub 2}O{sub 3} and {sup 153}Eu{sub 2}O{sub 3} were used for the neutron diffraction work because of the enormous absorption cross section of the natural isotopic mixtures for thermal neutrons. The isotopic purity was determined by inductively coupled plasma - mass spectrometry to be 98.9% for {sup 154}Sm and 99.8% for {sup 153}Eu. Advanced analysis of the neutron diffraction data suggest that the bound coherent scattering lengths of {sup 154}Sm and {sup 153}Eu need to be revised. We tentatively propose b{sub c}({sup 154}Sm) = 8.97(6) fm and b{sub c}({sup 153}Eu) = 8.85(3) fm for a neutron wavelength of 186.6 pm to be better values for these isotopes, showing up to 8% deviation from accepted literature values. It is shown that inaccurate scattering lengths may result in severe problems in crystal structure refinements causing erroneous structural details such as occupation parameters, which might be critically linked to physical properties like superconductivity in multinary oxides.

  19. Highly CO2-Tolerant Cathode for Intermediate-Temperature Solid Oxide Fuel Cells: Samarium-Doped Ceria-Protected SrCo0.85Ta0.15O3-δ Hybrid.

    Science.gov (United States)

    Li, Mengran; Zhou, Wei; Zhu, Zhonghua

    2017-01-25

    Susceptibility to CO2 is one of the major challenges for the long-term stability of the alkaline-earth-containing cathodes for intermediate-temperature solid oxide fuel cells. To alleviate the adverse effects from CO2, we incorporated samarium-stabilized ceria (SDC) into a SrCo0.85Ta0.15O3-δ (SCT15) cathode by either mechanical mixing or a wet impregnation method and evaluated their cathode performance stability in the presence of a gas mixture of 10% CO2, 21% O2, and 69% N2. We observed that the CO2 tolerance of the hybrid cathode outperforms the pure SCT15 cathode by over 5 times at 550 °C. This significant enhancement is likely attributable to the low CO2 adsorption and reactivity of the SDC protective layer, which are demonstrated through thermogravimetric analysis, energy-dispersive spectroscopy, and electrical conductivity study.

  20. First-principles study of structural stability, elastic and electronic properties of ternary rare earth-transition metal—Borides and carbides (RT{sub x}Z, R=Sc, Y, and La, T=Pt and Pd, Z=B and C, and x=2, 3, and 4)

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Tiankai; Wang, Yachun; Li, Hui [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Lian, Jie [Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Zhang, Jingwu, E-mail: zjw@ysu.edu.cn [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Gou, Huiyang, E-mail: huiyang.gou@gmail.com [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2013-12-15

    Using first-principles total energy calculations (CASTEP code), the structural stability, elastic, and electronic properties of ternary rare earth-transition metal borides and carbides (RT{sub x}Z, R=Sc, Y, and La, T=Pt and Pd, Z=B and C, and x=2, 3, and 4) compounds were studied. Results show that RT{sub 3}Z compounds with tetragonal P4mm structure are energetically more favorable than usually cubic perovskite-type structure. Furthermore, RT{sub 3}Z with perovskite structure is found to be mechanically unstable with the negative C{sub 44}. Formation enthalpy calculations indicate that Pt-based borides are easier to be synthesized compared with Pd-based ones and counterpart carbides, respectively. Elastic constants, bulk moduli, shear moduli, Young's moduli, and Poisson's ratio of studied compounds have been calculated. Also, all the studied compounds show ductile behavior. Moreover, total and partial density of states (DOSs) and bonding charge density were employed to elucidate the bonding features of these compounds. The results reveal that the covalency between Pt-5d and Z-2p as well as T-nd (n=4 for Pd and 5 for Pt) and B-2p states, are the cause of the relatively higher elastic moduli of Pt-based compounds and R–T-borides, respectively.

  1. Ferrites Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 4} doped with samarium: structural analysis, morphological and electromagnetic; Ferritas Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 4} dopada com samario: analise estrutural, morfologica e eletromagnetica

    Energy Technology Data Exchange (ETDEWEB)

    Costa, A.C.F.M.; Diniz, A.P., E-mail: anacristina@dema.ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academinca de Engenharia de Materiais; Viana, K.M.S. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, PE (Brazil). Escola de Ciencias e Tecnologia; Cornejo, D.R. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica; Kiminami, R.H.G.A. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Engenharia de Materiais

    2010-07-01

    This paper proposes to investigate the sintering at 1200 deg C/2h of Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2-x}Sm{sub x}O{sub 4} ferrite doped with 0.05; 0.075 e 0.1 mol of Sm synthesized by combustion reaction to evaluate the performance materials as absorbers of electromagnetic radiation. The influence of the concentration of samarium on the structure, morphology and electromagnetic properties of ferrites was studied. The resulting samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), magnetic measurements and reflectivity measurements in the frequency range between 8-12 GHz. The results showed that increasing the concentration of samarium caused a decrease in particle size of the samples, encouraging, therefore, to obtain materials with better values of magnetization and reflectivity, allowing for use as absorbers in narrow-band frequency between 9-10 GHz. (author)

  2. Crystal Growth, Structures, and Properties of the Complex Borides, LaOs 2 Al 2 B and La 2 Os 2 AlB 2

    Energy Technology Data Exchange (ETDEWEB)

    Bugaris, Daniel E.; Han, Fei; Im, Jino; Chung, Duck Young; Freeman, Arthur J.; Kanatzidis, Mercouri G.

    2015-08-17

    Single crystals of two novel quaternary metal borides, LaOs2Al2B and La2Os2AlB2, have been grown from La/Ni eutectic fluxes. LaOs2Al2B crystallizes in tetragonal space group P4/mmm with the CeCr2Si2C-type structure, and lattice parameters a = 4.2075(6) angstrom and c = 5.634(1) angstrom. La2Os2AlB2 exhibits a new crystal structure in monoclinic space group C2/c with lattice parameters a = 16.629(3) angstrom, b = 6.048(1) angstrom, c = 10.393(2) angstrom, and beta = 113.96(3)degrees. Both structures are three-dimensional frameworks with unusual coordination (for solid-state compounds) of the boron atoms by transition metal atoms. The boron atom is square planar in LaOs2Al2B, whereas it exhibits linear and T-shaped geometries in La2Os2AlB2. Electrical resistivity measurements reveal poor metal behavior (rho(30)0 (K) similar to 900 mu Omega cm) for La2Os2AlB2, consistent with the electronic band structure calculations, which also predict a metallic character for LaOs2Al2B.

  3. Retrospective evaluation of bone pain palliation after samarium-153-EDTMP therapy Avaliação retrospectiva do tratamento da dor óssea metastática com Samário-153-EDTMP

    Directory of Open Access Journals (Sweden)

    Marcelo Tatit Sapienza

    2004-01-01

    Full Text Available PURPOSE: The aim of this study was to evaluate the degree of metastatic bone pain palliation and medullar toxicity associated with samarium-153-EDTMP treatment. METHODS: Seventy-three patients with metastatic bone pain having previously undergone therapy with samarium-153-EDTMP (1 mCi/kg were retrospectively evaluated. Routine follow-up included pain evaluation and blood counts for 2 months after treatment. Pain was evaluated using a subjective scale (from 0 to 10 before and for 8 weeks after the treatment. Blood counts were obtained before treatment and once a week for 2 months during follow-up. Dosimetry, based upon the urinary excretion of the isotope, was estimated in 41 individuals, and the resulting radiation absorbed doses were correlated with hematological data. RESULTS: Reduction in pain scores of 75% to 100% was obtained in 36 patients (49%, with a decrease of 50% to 75%, 25% to 50%, and 0% to 25% in, respectively, 20 (27%, 10 (14%, and 7 (10% patients. There was no significant relationship between the pain response and location of the primary tumor (breast or prostate cancer. Mild to moderate myelosuppression was noted in 75.3% of patients, usually with hematological recovery at 8 weeks. The mean bone marrow dose was 347 ± 65 cGy, and only a weak correlation was found between absorbed dose and myelosuppression (Pearson coefficient = .4. CONCLUSIONS: Samarium-153-EDTMP is a valuable method for metastatic bone pain palliation. A mild to moderate and transitory myelosuppression is the main toxicity observed after samarium therapy, showing a weak correlation with dosimetric measures.OBJETIVO: O presente trabalho teve por objetivo avaliar o efeito paliativo da dor e a toxicidade medular associados ao tratamento com Samário-153-EDTMP em pacientes com metástases ósseas. MÉTODOS: O estudo foi realizado de forma retrospectiva, a partir do levantamento de prontuário de 178 pacientes submetidos a tratamento com 1mCi/kg de 153Sm

  4. The dynamics of the laser-induced metal-semiconductor phase transition of samarium sulfide (SmS); Die Dynamik des laserinduzierten Metall-Halbleiter-Phasenuebergangs von Samariumsulfid (SmS)

    Energy Technology Data Exchange (ETDEWEB)

    Kaempfer, Tino

    2009-12-15

    The present thesis is dedicated to the experimental study of the metal-semiconductor phase transition of samarium sulfide (SmS): Temperature- and time-resolved experiments on the characterization of the phase transition of mixed-valence SmS samples (M-SmS) are presented. The measurement of the dynamics of the laser-induced phase transition pursues via time-resolved ultrashort-time microscopy and by X-ray diffraction with sub-picosecond time resolution. The electronic and structural processes, which follow an excitation of M-SmS with infrared femtosecond laser pulses, are physically interpreted on the base of the results obtained in this thesis and model imaginations. [German] Die vorliegende Arbeit ist der experimentellen Untersuchung des Metall-Halbleiter-Phasenuebergangs von Samariumsulfid (SmS) gewidmet. Es werden temperatur- und zeitaufgeloeste Experimente zur Charakterisierung des Phasenuebergangs gemischt-valenter SmS Proben (M-SmS) vorgestellt. Die Messung der Dynamik des laserinduzierten Phasenuebergangs erfolgt ueber zeitaufgeloeste Ultrakurzzeit-Mikroskopie und durch Roentgenbeugung mit subpikosekunden Zeitaufloesung. Die elektronischen und strukturellen Prozesse, welche einer Anregung von M-SmS mit infraroten Femtosekunden-Laserpulsen folgen, werden auf der Basis der in dieser Arbeit gewonnenen Ergebnisse und Modellvorstellungen physikalisch interpretiert. (orig.)

  5. Computer Modeling of Ceramic Boride Composites

    Science.gov (United States)

    2014-11-01

    coefficients of thermal expansion. Approximately linear expansion coefficient of the composite is determined by the relation [52] EEE BBBAAAk...1 δαδαα ⋅+⋅= , (58) where AE and BE are Young moduli of components, and E – average modulus for composition BBAA EEE δδ

  6. Magnesium Aluminum Borides as Explosive Materials

    Science.gov (United States)

    2011-12-20

    Dryer , H. Rabitz, R. C. Brown, and C. E. Kolb, “Effect of Fluorine on the Combustion of “Clean” Surface Boron Particles,” Combustion and Flame, 112 507...521 (1998). 71. W. Zhou, R. A. Yetter, F. L. Dryer , H. Rabitz, R. C. Brown, and C. E. Kolb, “A Comprehensive Physical and Numerical Model of Boron...251-257 (1970). 114. T. Abu-Hamed, J. Karni, and M. Epstein, “The Use of Boron for Thermochemical Storage and Distribution of Solar Energy,” Solar

  7. A NOVEL SAMARIUM COMPLEX WITH INTERESTING ...

    African Journals Online (AJOL)

    INTRODUCTION. Fluorescent materials, particularly blue fluorescent materials have gained strong interest because ... emitting complexes in different technical applications, such as emitting materials for organic light emitting ..... properties of three novel two-dimensional lanthanide coordination polymers with mixed aromatic ...

  8. Pyroelectric Ferroelectric and Resistivity Studies on Samarium ...

    African Journals Online (AJOL)

    Barium Strontium Sodium Niobate (Ba1-xSrx)2NaNb5O15 (BSNN) belongs to tungsten bronze ferroelectric morphotrophic phase boundary (MPB) system at x = 0.6, having large spontaneous polarisation, pyroelectric coefficient and low dielectic constant and is expected to be applicable for piezoceramic filter and ...

  9. A NOVEL SAMARIUM COMPLEX WITH INTERESTING ...

    African Journals Online (AJOL)

    emitting complexes in different technical applications, such as emitting materials for organic light emitting diodes, sensitizers in solar energy conversion, chemical sensors and so forth [6-9]. The ability of bipy to act as a rigid ..... properties of three-dimensional organic-inorganic hybrids based on α-metatungstate. Inorg. Chim.

  10. Determination of specific radioactivity of samarium-153 product. 1. Quantitative determination of samarium by spectrophotometry

    Energy Technology Data Exchange (ETDEWEB)

    Izumo, Mishiroku [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nemoto, Masahiro [Tokyo Nuclear Service Co., Ltd., Tokyo (Japan)

    2002-03-01

    On the specific radioactivity of Sm-153 for the radiotherapy of cancers, a simple method for determination of the amount of Sm was described. The method used Arsenazo III as a colorimetric reagent. The sample irradiated in the reactor was dissolved in 1M HCl solution. A small part of it was taken and mixed with Arsenazo III at pH 3.2, and the amount of Sm was determined by the spectrophotometric method at a wavelength of 652 nm. The molar absorptivity of Sm at 652 nm was 6.6x10{sup 3} m{sup -1}{center_dot}mm{sup -1}. The error of measurement in the partial different conditions was about 2% of the value determined. The effects of impurities, Fe, Zn and Cu mixing in the Sm during operation, were clarified. (author)

  11. Radiolesão vascular como efeito deletério da braquiterapia intra-arterial com dose elevada de Samário-153 em coelhos hipercolesterolêmicos Vascular radiolesion as a deleterious effect of high-dose-rate intraarterial brachytherapy with Samarium-153 in hypercholesterolemic rabbits

    Directory of Open Access Journals (Sweden)

    Dalton Bertolim Précoma

    2006-10-01

    Full Text Available OBJETIVO: Este estudo tem por objetivo avaliar as alterações vasculares morfológicas e morfométricas induzidas pela braquiterapia com Samário-153 (153 Sm em coelhos hipercolesterolêmicos, com doses elevadas. MÉTODOS: Foram analisados 43 coelhos hipercolesterolêmicos, brancos, da raça New Zealand, e o total de 86 artérias ilíacas submetidas a lesão por balão de angioplastia. Divididos em três grupos: dois (GI irradiados com as doses de 15Gy (n=14 e 60Gy (n=36 e um grupo controle (n=36. Foram realizadas avaliação histológica morfométrica e análise histológica qualitativa para análise tecidual. RESULTADOS: Foram observadas uma redução significativa da neoproliferação intimal (NPI no GI 15 Gy (pOBJECTIVE: This study was designed to evaluate vascular morphological and morphometric changes induced by brachytherapy with samarium-153 (Sm-153 at high doses in hypercholesterolemic rabbits. METHODS: Forty-three New Zealand White hypercholesterolemic rabbits were analyzed, and the total of 86 iliac arteries underwent balloon angioplasty injury. The rabbits were divided into three different groups: two irradiation groups (IG assigned to 15 Gy (n=14 and 60 Gy (n=36 irradiation doses, respectively, and a control group (n = 36. Histomorphometric and qualitative histological analyses were performed for tissue evaluation. RESULTS: Significant reductions were found in neointimal proliferation (NIP (p< 0.0001, media area (MA (p<0.0001 and percent stenosis (p<0.0001 in the 15-Gy IG, compared to the other groups. The 60-Gy IG had the higher rate of NIP, increase in media and vessel areas (VA and percent stenosis. The 60-Gy IG also showed the greatest number of xanthomatous cells (60-Gy IG: 86.11% and 15-Gy IG: 14.29%, p<0.0001 and the highest amount of hyaline amorphous tissue (60-Gy IG:58.33% and 15-Gy IG:0%, p=0.0001 and vascular proliferation (60-Gy IG:30.56% and 15-Gy IG:0%, p=0.0221. No statistically significant differences were found

  12. NICKEL ALUMINIDE SYNTHESIS REINFORCED WITH MOLYBDENUM BORIDE COMPOSITE

    Directory of Open Access Journals (Sweden)

    Mr. Khosen ф Ri

    2016-06-01

    Full Text Available The authors study obtaining a composite material NiAl - Mo2B5 while carrying out thermally coupled reactions of self-propagating high-temperature synthesis with a deoxidizing aluminothermal stage. The authors established ultimate and phase composition of the obtained composite. The microstructure is studied. It is shown that the composite consists of the intermetallic phase NiAl with Mo2B5 inclusions.

  13. NICKEL ALUMINIDE SYNTHESIS REINFORCED WITH MOLYBDENUM BORIDE COMPOSITE

    OpenAIRE

    Mr. Khosen ф Ri; Mr. Victor V. Gostishchev; Ms. Anastasia V. Medneva; Mr. Sergei N. Khimukhin; Mr. Ivan A. Astapov

    2016-01-01

    The authors study obtaining a composite material NiAl - Mo2B5 while carrying out thermally coupled reactions of self-propagating high-temperature synthesis with a deoxidizing aluminothermal stage. The authors established ultimate and phase composition of the obtained composite. The microstructure is studied. It is shown that the composite consists of the intermetallic phase NiAl with Mo2B5 inclusions.

  14. Fundamental Thermal and Mechanical Properties of Boride Ceramics

    Science.gov (United States)

    2014-02-28

    1600°C and a two-color pyrometer above 1500°C. Heating rates as high as 500°C/min have been achieved. To date, four point bend tests as described by...a two-color optical pyrometer and a programmable PID controller. Water cooled graphite pushrods and a fully articulated graphite 4-point bend...Mechanical Stress Evaluation by Neutrons and Synchrotron Radiation , November 10-12, 2009, Mito, Japan. 20. J. Watts, G.E. Hilmas, and W.G. Fahrenholtz

  15. Development of Boride Composite Materials for Cold Cathode Devices

    Science.gov (United States)

    1981-05-01

    pop. 775, 1979. Johnson, R., "The Lanthanum-Bormn System," J of Phys. Chem, Vol 65, 1961, p. 909. Kanitkar , P., "Field Emissicn Studies of the...Ianthanum HexaborideA’unqsten Sys ," J. Physics D: App!. Phys. Vol 9, 1976 pp L165-LI68. Kanitkar , P. L. "Field Emissicn Studi es of the Lanthanum

  16. Optical characteristics of transparent samarium oxide thin films ...

    Indian Academy of Sciences (India)

    2016-10-07

    Oct 7, 2016 ... 1Department of Physics, Faculty of Science, Taif University, Taif 888, Saudi Arabia. 2Department of Physics, Faculty of Education, Ain Shams University, Roxy 11757, Cairo, Egypt. 3Materials Science Unit, Department of Chemistry, Faculty of Science, Tanta University, 31725 Tanta, Egypt. 4Department of ...

  17. Optical properties of lead–tellurite glasses doped with samarium ...

    Indian Academy of Sciences (India)

    The optical properties of a new family of Sm2O3–(40–)PbO–60TeO2 glasses are investigated. The optical absorption spectra were recorded at ... The refractive index, molar refraction and polarizability of oxide ions have been calculated by using Lorentz–Lorentz relations. The non-linear variations of the above optical ...

  18. Optical properties of lead–tellurite glasses doped with samarium ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The optical properties of a new family of xSm2O3–(40–x)PbO–60TeO2 glasses are investigated. The optical absorption spectra were recorded at room temperature in the UV-visible region. From the absorption edge studies, the values of optical bandgap energies have been evaluated. The refractive index, molar ...

  19. Measurement of radiative lifetime in atomic samarium using ...

    Indian Academy of Sciences (India)

    2014-02-08

    Feb 8, 2014 ... In this paper, we report the investigations of lifetime measurement of odd-parity energy level 19009.52 cm. −1 .... introduced by an electronic delay generator between the two Q-switch pulses of Nd-YAG laser. The slope of the .... Our values of the lifetimes are free from the common systematic errors. Thus ...

  20. A novel samarium complex with interesting photoluminescence and ...

    African Journals Online (AJOL)

    The 4,4'-Hbipy moieties, isolated nitrates and [Sm(H2O)4(NO3)3] species are held together via hydrogen bonds and p…p interactions to form a 3-D supramolecular framework. Luminescent investigation reveals a strong emission in blue region. Optical absorption spectrum of 1 reveals the presence of an optical gap of 3.60 ...

  1. Lithium samarium polyphosphate, LiSm(PO34

    Directory of Open Access Journals (Sweden)

    Dan Zhao

    2010-02-01

    Full Text Available The mixed-metal rare-earth polyphosphate LiSm(PO34 consists of a three-dimensional framework in which zigzag [(PO3n]n− chains with a periodicity of four PO4 tetrahedra are connected through Li+ and Sm3+ ions (both with 2. symmetry.

  2. Sodium samarium tetrakis(polyphosphate, NaSm(PO34

    Directory of Open Access Journals (Sweden)

    Dan Zhao

    2010-07-01

    Full Text Available NaSm(PO34 has been prepared by solid state reactions. It belongs to type II of the structural family of MILnIII(PO34 compounds (MI = alkali metal and LnIII = rare earth metal and is composed of ∞(PO3n]n− polyphosphate chains with a repeating unit of four PO4 tetrahedra. The chains extend parallel to [100] and share O atoms with irregular SmO8 polyhedra, forming a three-dimensional framework which delimits tunnels occupied by Na+ cations in a distorted octahedral environment.

  3. Isotopic Ratios of Samarium by TIMS for Nuclear Forensic Application

    Energy Technology Data Exchange (ETDEWEB)

    Louis Jean, James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Inglis, Jeremy David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-08

    The isotopic ratio of Nd, Sm, and Gd can provide important information regarding fissile material (nuclear devices, reactors), neutron environment, and device yield. These studies require precise measurement of Sm isotope ratios, by either TIMS or MC-ICP-MS. There has been an increasing trend to measure smaller and smaller quantities of Sm bearing samples. In nuclear forensics 10-100 ng of Sm are needed for precise measurement. To measure sub-ng Sm samples using TIMS for nuclear forensic analysis.

  4. Synthesis of copper, silver, and samarium chalcogenides by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Ohtani, T.; Maruyama, K.; Ohshima, K. [Okayama Univ. of Science (Japan). Lab. for Solid State Chemistry

    1997-03-01

    CuInX{sub 2} (X = S, Se, Te), Ag{sub 2}S, Ag{sub 2}Se, Ag{sub 3}Te{sub 2}, Ag{sub 1.9}Te, AgCuSe, Sm{sub 3}Se{sub 4}, Sm{sub 2}Se{sub 3}, and SmTe were synthesized by a mechanical alloying method, using a high-energy planetary ball mill. The compounds were obtained by milling mixtures of the elements with desired ratios in agate or Cu-Be vials for 60--180 min.

  5. Oriented growth of thin films of samarium oxide by MOCVD

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Thin films of Sm2O3 have been grown on Si(100) and fused quartz by low-pressure chemical va- pour deposition using an adducted β-diketonate precursor. The films on quartz are cubic, with no preferred orientation at lower growth temperatures (~ 550°C), while they grow with a strong (111) orientation as the.

  6. 150 KVA Samarium Cobalt VSCF Starter Generator Electrical System

    Science.gov (United States)

    1978-12-01

    considerable hand labor. Addition of a provision for suitable electrical connection by the SCR manufacturer wou;d be desirable for production runs. Predicted...licen- sing the holder or any other person or corporation, or conveying any rights or permission to manufacture , use, or sell any patented invent,’n...tesile strength to contain the magnets and pole pieces up through the overspeed rating of the rotor. The cho.;en process uses maraging steel as the

  7. Optical properties of samarium doped zinc–tellurite glasses

    Indian Academy of Sciences (India)

    Glasses with the composition, (Sm2O3)(ZnO)(40–)(TeO2)(60), were prepared by conventional melt quenching method. The density, molar volume, and optical energy band gap of these glasses have been measured. The refractive index, molar refraction and polarizability of oxide ion have been calculated by using ...

  8. Contribution to the study of samarium-151 excited levels; Contribution a l'etude des niveaux excites du samarium-151

    Energy Technology Data Exchange (ETDEWEB)

    Locard, P. [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Grenoble, 38 (France)

    1967-07-01

    The nucleus of {sup 151}Sm, which has 89 neutrons, happens to be on the lower edge of the deformed nuclei of region II. Therefore, the study of its levels is very interesting for the verification of the goodness of the collective models for deformed nuclei when the deformation is small (we introduce these models in the first chapter). {sup 151}Sm has often been studied, but the direct gamma spectrum measured with a lithium drift-germanium detector (chapter 3) shows many high energy transitions which did not appear in the previous level schemes. In order to settle these transitions, we have undertaken gamma-gamma coincidence spectra (as well as sum-coincidence spectra) experiments with a scintillation spectrometer designed in our laboratory (chapter 2). The investigation of the intensities of these coincidences leads us to modify the last proposed level schemes: we suppress the levels at 405,5 and 650 keV, we add levels at 245,6 - 306,6 - 522 - 952 and 962 keV. We have also verified the multipolarities of the main transitions and measured the half-lives of a few levels (chapter 3) (we find a half-life of 1.1 {+-} 0.5 nanosecond for the level at 167,7 keV). In chapter 4, we compare our results to the predictions of the models described in chapter 1. (author) [French] Le noyau de {sup 151}Sm, qui possede 89 neutrons, se trouve a la limite inferieure des noyaux deformes de la region II. L'etude de ses niveaux excites est donc d'un interet tout particulier pour la verification de la validite des differents modeles collectifs pour les noyaux deformes, lorsque la deformation est petite (nous introduisons ces modeles dans un premier chapitre). Le {sup 151}Sm a deja fait l'objet de nombreuses etudes, mais le spectre gamma direct fait avec une jonction de germanium compense au lithium (chapitre 3), nous a montre l'existence d'un grand nombre de transitions de hautes energies qui ne sont pas placees dans les schemas proposes jusqu'a ce jour. Pour preciser la place de ces transitions, nous avons donc entrepris des experiences de coincidences gamma-gamma (et de ''spectre de somme'') a l'aide d'un ensemble de spectrometrie a scintillation realise au laboratoire (chapitre 2). L'etude des intensites de ces coincidences (chapitre 3) nous amene a modifier le dernier schema propose: nous supprimons les niveaux a 405,5 et 650 keV, nous ajoutons des niveaux a 245,6 - 306,6 - 522 - 952 et 962 keV. Nous avons egalement verifie la multipolarite des principales transitions et mesure la duree de vie de certains des niveaux (chapitre 3) (nous trouvons une periode de 1,1 {+-} 0,5) nanoseconde pour le niveau a 167,7 keV). Le chapitre 4 est enfin consacre a la comparaison de nos resultats avec les predictions des differents modeles decrits au chapitre 1. (auteur)

  9. Microstructure and properties of gravity sintered 316l stainless steel powder with nickel boride addition

    Directory of Open Access Journals (Sweden)

    Božić Dušan

    2016-01-01

    Full Text Available The present work demonstrates a procedure for synthesis of stainless steel powder by gravity sintering method. As an additive to the basic powder, NiB powder was added in the amount of 0.2 - 1.0 wt.%. Gravity sintering was done in vacuum, at the temperatures of 1100°C-1250°C, in the course of 3 - 60 min, using ceramic mould. Structural characterization was conducted by XRD, and microstructural analysis by optical and scanning electron microscope (SEM. Mechanical properties were investigated by tensile tests with steel rings. Density and permeability were determined by standard techniques for porous samples. Gravity sintered stainless steel with NiB addition had more superior mechanical and physico-chemical properties compared to stainless steel obtained by standard powder metallurgy procedures - pressing and sintering. [Projekat Ministarstva nauke Republike Srbije, br. 172005

  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

    2017-03-01

    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.

  11. 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...

  12. 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.

  13. Oxidation behavior of multiphase molybdenum-molybdenum silicide-molybdenum silicide boride intermetallics

    Science.gov (United States)

    Dheeradhada, Voramon Supatarawanich

    Multiphase Mo-Mo3Si-Mo5SiB2(T2) alloys of various compositions and microstructures were investigated for oxidation resistance at 800 and 1300°C. The alloys varied in Si/B ratio from 1:1 to 1:2 and their microstructures were processed to have the Mo phase distributed as a continuous phase or as discrete particles. At 800°C, the alloys exhibited poor oxidation resistance regardless of Si/B ratio or their microstructures. Oxide scale consisted of MoO 3 and boron-containing glass. Alloys with lower Si/B ratio yielded silicate glass with lower viscosity that resulted in lower weight loss compared to the high Si/B ratio alloys. Intermediate layers of Mo and Mo-Si-O were observed adjacent to Mo5SiB2 and Mo3Si phases, respectively. At 1300°C, the multiphase alloys developed a protective glass scale with an intermediate layer of (Mo+glass) between the base alloy and outer glass scale. Boron-lean silicate glass was essential for the protection from further oxidation. For oxidation resistance at 1300°C, alloys require a high Si/B ratio. In terms of microstructures, the multiphase alloys consisting of small Mo particles uniformly dispersed in fine spacing of silicide phases provide better oxidation resistance than the alloys with continuous Mo dendrites. Glass preferentially formed at Mo3Si rather than at T2 phase. Vapor-solid diffusion experiments were carried out with single phase alloys containing either Mo3Si or T2 as the major phase, and the multiphase Mo-10Si-10B(at%) alloy. The alloys were exposed to vacuum to induce silicon loss resulting in the formation of a Mo layer. In addition, microprobe analysis was carried out for the determination of composition profiles across the (Mo+glass) layer and the external glass scale formed on the Mo-13.2Si-13.2B (at%) alloy oxidized at 1300°C. The microprobe data were analyzed for interdiffusion fluxes and interdiffusion coefficients with the aid of a computer program called "MultiDiFlux (c)". The effective interdiffusion coefficients for Mo, Si, B, and O in various phases were also determined. The motion of the (metal/Mo+glass) and (Mo+glass/glass) interfaces was examined. An average effective interdiffusion coefficient of silicon in molybdenum at 1300°C was estimated as 10 -17 m2/s. Moreover, interdiffusion coefficients for each component in the Mo+glass layer were evaluated on the basis of Mishin's analysis.

  14. Formation of molybdenum boride cermet coating by the detonation spray process

    Science.gov (United States)

    Yang, Gao; Zu-Kun, Hei; Xiaolei, Xu; Gang, Xin

    2001-09-01

    The effects of the powder particle size and the acetylene/oxygen gas flow ratio during the detonation spray process on the amount of molybdenum phase, porosity, and hardness of the coatings using MoB powder were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), etc. The results show that the presence of metallic molybdenum in the coating results from decomposition of MoB powder during thermal spray. The compositions of the coatings are metallic Mo, MoB, and Mo2B, which are different from the phases of the original powder. The amount of molybdenum phase increases monotonously with the oxygen/acetylene ratio, but the increasing rate for the fine powder is faster than that for the coarse powder. The porosity and hardness of the coating are related to the amount of molybdenum phase. The phase constitution of the coating is discussed.

  15. The Physics and Chemistry of carbides, Nitrides and Borides. Volume 185

    Science.gov (United States)

    1990-01-01

    orbits around the axial field lines. Near the substrate, the ECR resonance conditions allow the electrons to receive resonance impulses during each... orbit so these electrons acquire a higher energy than electrons 141 elsewhere in the cavity. Thus, the plasma forms preferentially in the region of these...34frittage et caracterisation de cdramiques dans le syst me zirconium- carbone-oxyg~ne", E.N.S. Mines de Saint-Etienne, (1986), Thtse (n* 54 C.I.). [102

  16. Boride ceramics covalent functionalization and its effect on the thermal conductivity of epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Zhi-Qiang, E-mail: yuzhiqiang@fudan.edu.cn [Department of Materials Science, Fudan University, 200433 Shanghai (China); Wu, Yicheng [Department of Materials Science, Fudan University, 200433 Shanghai (China); Wei, Bin; Baier, Horst [Institute of Lightweight Structures, Technical University Munich (TUM), Boltzmannstr. 15, D-85747 Garching (Germany)

    2015-08-15

    Zirconium diboride/aluminium oxide (ZrB{sub 2}/Al{sub 2}O{sub 3}) composite particles were functionalized with epoxide functionalized γ-glycidoxypropyltrimethoxysilane by the covalent bonding approach to improve the interfacial compatibility of composite particles in epoxy matrix. The composites of epoxy resin filled with functionalized ZrB{sub 2}/Al{sub 2}O{sub 3} were prepared by in situ bulk condensation polymerization of bisphenol A and epichlorohydrin in the presence of ZrB{sub 2}/Al{sub 2}O{sub 3}. The heat-conducting properties of composites were investigated by the finite element method (FEM) and the thermal conductivity test. The finite-element program ANSYS was used for this numerical analysis, and three-dimensional spheres-in-cube lattice array models were built to simulate the microstructure of composite materials for different filler contents. The thermal conductivity of composites was determined by laser flash method (LFA447 Nanoflash), using the measured heat capacity and thermal diffusivity, with separately entered density data. The results show that the effective chemical bonds are formed between ZrB{sub 2}/Al{sub 2}O{sub 3} and γ-glycidoxypropyltrimethoxysilane after the surface functionalization. The interfacial compatibility and bonding of modified particles with the epoxy matrix are improved. The thermal conductivities of functionalized composites with 3 vol% and 5 vol% loading are increased by 8.3% and 12.5% relative to the unmodified composites, respectively. Comparison of experimental values and calculated values of the thermal conductivity, the average relative differences are under 5%. The predictive values of thermal conductivity of epoxy composites are in reasonable agreement with the experimental values. - Highlights: • The surfaces of ZrB{sub 2}/Al{sub 2}O{sub 3} were functionalized by silane coupling agents. • The thermal conductivity (TC) of modified epoxy composites is improved significantly. • The FEM values of TC are in reasonable agreement with the experimental values.

  17. Improving Hardness and Toughness of Boride Composites Based on AIMgB14

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Justin Steven [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    The search for new super-hard materials has usually focused on strongly bonded, highly symmetric crystal structures similar to diamond. The two hardest single-phase materials, diamond and cubic boron nitride (cBN), are metastable, and both must be produced at high temperatures and pressures, which makes their production costly. In 2000, a superhard composite based on a low-symmetry, boron-rich compound was reported. Since then, many advances have been made in the study of this AlMgB14-TiB2 composite. The composite has been shown to exhibit hardness greater than either of its constituent phases, relying on its sub-micron microstructure to provide hardening and strengthening mechanisms. With possible hardness around 40 GPa, an AlMgB14 - 60 vol% TiB2 approaches the hardness of cBN, yet is amenable to processing under ambient pressure conditions. There are interesting aspects of both the AlMgB14 and TiB2 phases. AlMgB14 is comprised of a framework of boron, mostly in icosahedral arrangements. It is part of a family of 12 known compounds with the same boron lattice, with the metal atoms replaced by Li, Na, Y or a number of Lanthanides. Another peculiar trait of this family of compounds is that every one contains a certain amount of intrinsic vacancies on one or both of the metal sites. These vacancies are significant, ranging from 3 to 43% of sites depending on the composition. TiB2 is a popular specialty ceramic material due to its high hardness, moderate toughness, good corrosion resistance, and high thermal and electrical conductivity. The major drawback is the difficulty of densification of pure TiB2 ceramics. A combination of sintering aids, pressure, and temperatures of 1800 C are often required to achieve near full density articles. The AlMgB14 - TiB2 composites can achieve 99% density from hot-pressing at 1400 C. This is mostly due to the preparation of powders by a high-energy milling technique known as mechanical alloying. The resulting fine powders have high activity, and Fe from wear debris acts as a sintering aid. Mechanical alloying improves the sinterability of the composite material, it has the same effect on pure TiB2. TiB2 processed by high-energy milling has been found to achieve 99% theoretical density at 1400 C with the addition of ~1 wt% Fe. Both the AlMgB14 - TiB2 composites and pure TiB2 produced from these methods have enhanced mechanical properties due to their fine microstructures. These materials show exceptional promise in the field of wear resistance. This includes cutting tools, erosion resistant coatings, and low-friction sliding contacts to name a few. Under certain wear conditions, the composite material can show performance on par with that of current high-end cBN and WC materials tailored for wear resistance. The composite material also exhibits low reactivity with Ti alloys, a pre-requisite for effective machining of these alloys, a trait that few hard materials possess.

  18. Ground State Structures of Boron-Rich Rhodium Boride: An Ab Initio Study

    Science.gov (United States)

    Chu, Bin-Hua; Zhao, Yuan; Yan, Jin-Liang; Li, Da

    2018-01-01

    Not Available Supported by the Natural Science Foundation of Shandong Province under Grant Nos ZR2016AP02, ZR2016FM38 and ZR2016EMP01, the Innovation Project of Ludong University under Grant No LB2016013, the Open Project of State Key Laboratory of Superhard Materials of Jilin University under Grant No 201605, and the National Natural Science Foundation of China under Grant Nos 11704170 and 61705097.

  19. One-step synthesis of samarium-doped ceria and its CO catalysis

    Indian Academy of Sciences (India)

    Administrator

    Key Laboratory for Special Functional Aggregate Materials of Education Ministry,. School of Chemistry and Chemical ... been flourishing since its excellent electric properties were discovered in the 1980s.1 At present SDC is ... absolute ethanol three times and dried in an electric oven at 60°C overnight, and then calcined at ...

  20. Trichloridotris{N-[phenyl(pyridin-2-ylmethylidene]hydroxylamine-κ2N,N′}samarium(III

    Directory of Open Access Journals (Sweden)

    Yahong Li

    2012-03-01

    Full Text Available The SmIII ion in the title compound, [SmCl3(C12H10N2O3], shows a coordination number of nine with a slightly distorted tricapped trigonal prismatic geometry based on a Cl3N6 donor set. The molecular structure is stabilized by three intramolecular O—H...Cl hydrogen bonds.

  1. Biological studies of samarium-153 bleomycin complex in human breast cancer murine xenografts for therapeutic applications

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami-Samani, A. [Faculty of Nuclear Engineering and Physics, Amirkabir Univ. of Tech., Tehran (Iran); Ghannadi-Maragheh, M. [Faculty of Nuclear Engineering and Physics, Amirkabir Univ. of Tech., Tehran (Iran); Radiopharmaceutical Research and Development Lab. (RRDL), Nuclear Science and Technology Research Inst. (NSTRI), Tehran (Iran); Jalilian, A.R.; Mazidi, M. [Radiopharmaceutical Research and Development Lab. (RRDL), Nuclear Science and Technology Research Inst. (NSTRI), Tehran (Iran)

    2010-07-01

    In this work, a potential therapeutic DNA targeting agent, {sup 153}Sm-bleomycin complex ({sup 153}Sm-BLM), was developed and the tumor accumulation studies were performed using single photon emission computed tomography (SPECT) and scarification studies. {sup 153}Sm-BLM was prepared at optimized conditions (room temperature, 4-8 h, 0.1 mg bleomycin for 740-3700 MBq {sup 153}SmCl{sub 3}, radiochemical purity over 98%, HPLC, specific activity = 55 TBq/mmol). {sup 153}Sm-BLM was administered into human breast cancer murine xenografts and the biodistribution and imaging studies were performed up to 48 h. {sup 153}Sm-BLM demonstrated superior tumor accumulation properties in contrast with the other radiolabeled bleomycins with tumor:blood ratios of 41, 72 and 182 at 4, 24 and 48 h, respectively, and tumor:muscle ratios of 23, 33 and > 1490 at 4, 24 and 48 h, respectively, while administered intravenously. The SPECT images also demonstrated the obvious tumor uptake at the chest region of the breast-tumor bearing mice. These initial experiments demonstrate significant accumulation of {sup 153}Sm-BLM in tumor tissues. (orig.)

  2. Samarium oxide as a radiotracer to evaluate the in vivo biodistribution of PLGA nanoparticles

    CSIR Research Space (South Africa)

    Mandiwana, V

    2015-09-01

    Full Text Available .63 %ID/g) and liver (3.07 %ID/g), confirming that nanoparticles are rapidly removed from the blood by the RES, leading to rapid uptake in the liver and spleen. From the biodistribution data obtained, it is clear that polymeric nanoscale delivery systems...

  3. Nanostructured Samarium Doped Fluorapatites and Their Catalytic Activity towards Synthesis of 1,2,4-Triazoles

    National Research Council Canada - National Science Library

    Gangu, Kranthi Kumar; Maddila, Suresh; Maddila, Surya Narayana; Jonnalagadda, Sreekantha B

    2016-01-01

    ...) and their properties. The nanostructured Sm doped fluorapatites (Sm-FAp) were prepared by a co-precipitation method using four different amino acids, namely glutamic acid, aspartic acid, glycine and histidine...

  4. Samarium(III) picrate tetraethylene glycol complex: Photoluminescence study and active material in monolayer electroluminescent

    Energy Technology Data Exchange (ETDEWEB)

    Kusrini, Eny, E-mail: ekusrini@che.ui.ac.id [Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, 16424 Depok (Indonesia); Saleh, Muhammad I. [School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang (Malaysia); Yulizar, Yoki [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, 16424 Depok (Indonesia); Za' aba, Noor K.; Abd. Majid, W.H. [Solid State Research Laboratory, Department of Physics, Universiti Malaya, 50603 Kuala Lumpur (Malaysia)

    2011-09-15

    A mononuclear Sm(III) complex involving Pic and EO4 (where Pic=picrate anion and EO4=tetraethylene glycol) has been studied. It shows a bright-orange emission when used as active material in a monolayer electroluminescent device of ITO/EO4-Sm-Pic/Al. The crystal structure of the complex consists of [Sm(Pic){sub 2}(H{sub 2}O)(EO4)]{sup +} cation and [Pic]{sup -} anion. The Sm(III) ion is coordinated with nine oxygen atoms from one EO4 ligand in a pentadentate mode, two Pic anions each in bidentate and monodentate modes, and one water molecule. Both the terminal alcohol groups of the acyclic EO4 ligand were involved in the O-H...O hydrogen bonding by infinite one-dimensional (1D) chain within a symmetry direction [0 1 0]. The photoluminescence (PL) spectrum of the thin film shows the typical spectral features of the Sm(III) ion ({sup 4}G{sub 5/2}{yields}{sup 6}H{sub 7/2} transitions). The root-mean-square (rms) of the roughness of thin film is 30.605 nm and indicates that the formation of the monolayer electroluminescent device is not uniform and retains a high crystallinity. Typical semiconductor current-voltage (I-V) property was also observed in this device with threshold and turn voltages of 2.8 and 6.2 V, respectively. The [Sm(Pic){sub 2}(H{sub 2}O)(EO4)](Pic).H{sub 2}O complex can be applied as a luminescent center in OLED for bright-orange emission. - Highlights: > The [Sm(Pic){sub 2}(H{sub 2}O)(EO4)](Pic).H{sub 2}O complex is crystallized in triclinic with space group P-1. > The complex is applied as a emissive center in monolayer device structure of ITO/EO4-Sm-Pic/Al. > The photoluminescence spectrum of the crystalline and thin film shows a bright-orange emission. > The current-voltage property showed the turn on voltage of 6.2 V.

  5. Pulsed laser deposition and optical characterizations of the magnetic samarium orthoferrite

    Energy Technology Data Exchange (ETDEWEB)

    Berini, Bruno, E-mail: bruno.berini@uvsq.fr [Groupe d' Etude de la Matiere Condensee (GEMAC), CNRS, Universite de Versailles St. Quentin, 45, Av. des Etats-Unis, 78035 Versailles Cedex (France); Mistrik, Jan [Institute of Applied Physics and Mathematics, Faculty of Chemical Technology, University of Pardubice, Studentska 84, 532 10 Pardubice (Czech Republic); Dumont, Yves; Popova, Elena; Fouchet, Arnaud; Scola, Joseph; Keller, Niels [Groupe d' Etude de la Matiere Condensee (GEMAC), CNRS, Universite de Versailles St. Quentin, 45, Av. des Etats-Unis, 78035 Versailles Cedex (France)

    2012-01-01

    Pulsed Laser Deposition of magnetically ordered polycrystalline SmFeO{sub 3} films has been optimized onto SiO{sub 2} glass substrates as function of substrate temperature, oxygen pressure and pulsed laser fluency. Using a KrF excimer laser, crystallization temperature is found to be about 1048 K for a weak fluency of only 1.7 J cm{sup -2}. We show that this growth temperature can be reduced using higher fluency and that it is possible to obtain a film texturation along the c axis by reducing the oxygen pressure at given temperature and fluency. In a second part, we focus on the SmFeO{sub 3} optical constants determined by in situ ellipsometry using a stacking model and the Cauchy dispersion relation for SmFeO{sub 3} layer. We show a good correlation between the transmission and reflection calculated from these data and measured by ex situ spectrophotometry in the visible range.

  6. Nanostructured Samarium Doped Fluorapatites and Their Catalytic Activity towards Synthesis of 1,2,4-Triazoles

    Directory of Open Access Journals (Sweden)

    Kranthi Kumar Gangu

    2016-09-01

    Full Text Available An investigation was conducted into the influence of the amino acids as organic modifiers in the facile synthesis of metal incorporated fluorapatites (FAp and their properties. The nanostructured Sm doped fluorapatites (Sm-FAp were prepared by a co-precipitation method using four different amino acids, namely glutamic acid, aspartic acid, glycine and histidine. The materials were characterized by various techniques including X-ray diffraction (XRD, Fourier transform infra-red spectroscopy (FT-IR, field emission scanning electron microscopy (FE-SEM, energy-dispersive X-ray spectroscopy (EDX, high resolution transmission electron microscopy (HR-TEM, N2-adsorption/desorption isotherm, temperature programmed desorption (TPD and fluorescence spectrophotometry. Under similar conditions, Sm-FAp prepared using different amino acids exhibited distinctly different morphological structures, surface area and pore properties. Their activity as catalysts was assessed and Sm-FAp/Glycine displayed excellent efficiency in the synthesis of 1,2,4-triazole catalyzing the reaction between 2-nitrobenzaldehyde and thiosemicarbazide with exceptional selectivity and 98% yield in a short time interval (10 min. The study provides an insight into the role of organic modifiers as controllers of nucleation, growth and aggregation which significantly influence the nature and activity of the catalytic sites on Sm-FAp. Sm-FAp could also have potential as photoactive material.

  7. Body composition analysis by DEXA by using dynamically changing samarium filtration

    DEFF Research Database (Denmark)

    Gotfredsen, Arne; Baeksgaard, L; Hilsted, J

    1997-01-01

    , which depends on the current-absorber thickness. With this system we found a good agreement (r = 0.99) between reference and measured amounts of tissue or fat percentages in a plastic phantom and in smaller (approximately 0.5-4 kg) and larger (approximately 5-20 kg) piles of tissue (ox muscle and lard......). Scans of six healthy volunteers covered with combinations of beef and lard (approximately 5-15 kg) showed a good agreement (r = 0.99) between reference and DEXA values of added soft tissue mass and fat percentage. We conclude that the DEXA method (and, in particular, the Norland XR-36 using dynamic...

  8. Synthesis, thermal and photoluminescent properties of ZnSe- based oxyfluoride glasses doped with samarium

    Science.gov (United States)

    Kostova, I.; Okada, G.; Pashova, T.; Tonchev, D.; Kasap, S.

    2014-12-01

    Rare earth (RE) doped glasses and glass ceramic materials have recently received considerable attention because of their potential or realized applications as X-ray intensifying screens, phosphors, detectors, waveguides, lasers etc. [1]. In this work, we present a new RE doped ZnO-ZnSe-SrF2-P2O5-B2O3-Sm2O3-SmF3 (ZSPB) glass system synthesized by melt quenching technique. The resulting glasses were visually fully transparent and stable with glass the transition temperatures around 530°C. The thermal properties of this glass system were characterized by Modulated Differential Scanning Calorimetry (MDSC) measurements before and after annealing at 650°C. We have characterized these glasses by Raman spectroscopy and photoluminescence (PL) measurements over the UV-VIS range using light emitting diodes (LED) and laser diodes (LD) excitation sources. We have also irradiated thermally treated and non-treated glass samples by X-rays and have studied the resulting PL. We discuss the results in terms of previously reported models for Sm-doped Zn-borophosphate oxide, oxyfluoride and oxyselenide glasses.

  9. Laser-Induced Luminescence Study of Samarium(III) Thiodiglycolate Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Dong Yong; Lee, Eil Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kimura, Takaumi [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan)

    2003-09-15

    The hydration number of Sm(III) has been obtained by using the difference in the decay rate constants in H{sub 2}O and D{sub 2}O solutions. In general, k{sub obs}(H{sub 2}O) >> k{sub obs}(D{sub 2}O), k{sub obs}(D{sub 2}O) ≅ constant, and ligands are not as effective in causing non-radiative de-excitation of the excited state. For Sm(III), a relationship has been proposed in which the hydration number is related directly to the decay rate constant in H{sub 2}O. If there is no contribution from the ligand to the de-excitation of the luminescence excited state, the hydration of Sm(III) in the different complexes can be obtained directly from the values of k{sub obs} measured in H{sub 2}O. The number and the geometric distribution of solvent molecules around a metal ion in solution are an important factor in the structural and chemical behavior of cation. Indeed, such information has been utilized to design novel ionophores and receptors. However, there have been few studies of hydration structure for lanthanides. The fact that many f-element salts which have relatively large lattice energies are fairly soluble in water is a reflection of the strength of the interactions between the metal cations and water molecules.

  10. Oxygen Fugacity of the Martian Mantle from Pigeonite/Melt Partitioning of Samarium, Europium and Gadolinium

    Science.gov (United States)

    Musselwhite, S.; Jones, J. H.; Shearer, C.

    2004-01-01

    This study is part of an ongoing effort to calibrate the pyroxene/melt Eu oxybarometer for conditions relevant to the martian meteorites. There is fairly good agreement between a determinations using equilibria between Fe-Ti oxides and the estimates from Eu anomalies in shergottite augites in tenns of which meteorites are more or less oxidized. The Eu calibration was for angrite composition pyroxenes which are rather extreme. However, application of a calibration for martian composition augites 113 does not significantly reduce the discrepancy between the two methods. One possible reason for this discrepancy is that augites are non-liquidus. The use of pigeonite rather than augite as the oxy-barometer phase is considered. We have conducted experiments on martian composition pigeonite/melt REE partitioning as a function of fO2.

  11. Doping controlled spin reorientation in dysprosium-samarium orthoferrite single crystals

    Science.gov (United States)

    Cao, Shixun; Zhao, Weiyao; Kang, Baojuan; Zhang, Jincang; Ren, Wei

    2015-03-01

    As one of the most important phase transitions, spin reorientation (SR) in rare earth transition metal oxides draws much attention of emerging materials technologies. The origin of SR is the competition between different spin configurations which possess different free energy. We report the control of spin reorientation (SR) transition in perovskite rare earth orthoferrite Dy1-xSmxFeO3, a whole family of single crystals grown by optical floating zone method from x =0 to 1. Temperature dependence of the magnetizations under zero-field-cooling (ZFC) and field-cooling (FC) processes are studied. We have found a remarkable linear change of SR transition temperature in Sm-rich samples for x>0.2, which covers an extremely wide temperature range including room temperature. The a-axis magnetization curves under FCC process bifurcate from and then jump down to that of warming process (ZFC and FCW curves) in single crystals when x =0.5-0.9, suggesting complicated 4f-3d electron interactions among Dy3+-Sm3+, Dy3+-Fe3+, and Sm3+-Fe3+ sublattices of diverse magnetic configurations for materials physics and design. The magnetic properties and the doping effect on SR transition temperature in these single crystals might be useful in the spintronics device application. This work is supported by the National Key Basic Research Program of China (Grant No. 2015CB921600), and the National Natural Science Foundation of China (NSFC, Nos. 51372149, 50932003, 11274222).

  12. Synthesis, crystal structure and luminescent properties of a new samarium-fluorescein metal-organic framework

    Science.gov (United States)

    Thomas, Jesty; Ambili, K. S.

    2015-10-01

    A new metal-organic framework with empirical formula C43H30NO12Sm was solvothermally synthesized using SmCl3, fluorescein and N, N-Dimethyl formamide (DMF) and characterized by single crystal X-ray diffraction, powder X-ray diffraction, infrared spectroscopy, UV-Visible spectroscopy, scanning electron microscopy, optical microscopy, photoluminescence spectroscopy, CHN elemental analysis and thermogravimetric analysis. Single crystal X-ray diffraction revealed that the crystal structure belongs to the triclinic system, P-1 space group with a = 12.113 (6) Å, b = 12.1734 (7) Å, c = 13.2760(8) Å, α = 67.930(3)⁰, β = 87.779(3)⁰, γ = 77.603(3)⁰ and V = 1769.71 (17) Å3. The photoluminescence spectrum showed emission peaks at 550 nm, 600 nm and 647 nm due to the characteristic transitions 4G5/2 to 6H5/2, 4G5/2 to 6H7/2 and 4G5/2 to 6H9/2 respectively, when excited at 398 nm.

  13. High-temperature heat capacity of samarium and erbium titanates with pyrochlore structure

    Science.gov (United States)

    Denisova, L. T.; Chumilina, L. G.; Denisov, V. M.; Ryabov, V. V.

    2017-12-01

    Titanates Sm2Ti2O7 and Er2Ti2O7 with pyrochlore structure have been prepared by solid-phase synthesis in air from stoichiometric Sm2O3 (Er2O3)-TiO2 mixtures sequentially at 1673 and 1773 K. Hightemperature heat capacity of the oxide compounds has been determined by differential scanning calorimetry. Their thermodynamic properties have been calculated from experimental temperature dependence C p = f( T).

  14. Research and Development on Titanium Alloys

    Science.gov (United States)

    1949-10-31

    are being prepared by the Norton Company for evaluation. Titanium boride , tantalum boride , zirconium boride , tungsten boride , and molybdenum boride ...alloying additionO will be ex- tended. 9 Ternary alloys of manganese and carbon, manganese and vanadium, and molybdenum and tungsten, prepared by...graphite crucibles lined with tantalum carbide and turgsten boride as refractories for molten titanium,. Melts were prepared In crucibles made of zirconium

  15. Electrical and magnetic properties of several ruthenates and superconductivity in magnesium boride and MgCNi(3)

    Science.gov (United States)

    He, Tao

    2002-09-01

    Perovskite-based ruthenates have been receiving considerable attention both because of their interesting and variable magnetic properties, and because of the discovery of exotic superconductivity in the layered ruthenate Sr 2RuO4. Another perovskite, SrRuO3, is the only known oxide ferromagnet with a 4d transition metal, and magnetism is easily suppressed by Ca doping. The suppression of ferromagnetic interactions in SrxCa1-xRuO3 has frequently been attributed to the orthorhombic structural distortion, either through the crossover to classical antiferromagnetic interactions, or, alternatively, to a nearly ferromagnetic metal. This study reports the comparison of the magnetic properties of Srx(Na0.5La0.5)1-xRuO 3 to SrxCa1-xRuO3, showing that there is a much faster suppression of ferromagnetic interactions in the former case. Neither orthorhombic distortion nor cation size disorder can explain the observed difference. Instead, the difference may be attributed to charge disorder on the A-site, which greatly affects the local environment of Ru atoms and leads to the faster suppression of the long-range ferromagnetic state. The magnetic ground state of perovskite structure CaRuO3 has been enigmatic for decades. This study also shows that paramagnetic CaRuO 3 can be made ferromagnetic by very small amounts of partial substitution of Ru by various transition metals. The results are consistent with the recent proposal that CaRuO3 is not a classical antiferromagnet, but rather is poised at a critical point between ferromagnetic and paramagnetic ground states. Ti, Fe, Mn and Ni doping result in ferromagnetic behavior. The second part of this thesis is on the superconductivity of MgB 2 and MgCNi3. Since the discovery of superconductivity in MgB2 in January 2001, detailed information on its properties has been rapidly accumulated. The reported properties, the very simple structure, and the commercial availability of this material make MgB2 a favorite candidate for large scale and electronic applications. In thin film fabrication, the reactivity of MgB2 with substrate materials or insulating or metallic layers in multi-layer circuits is an important factor. In this work the reactivity of MgB2 with powdered forms of common substrate and electronic materials is studied. Some oxides and nitrides prove to be potentially good substrates for making thin films, while others, including some commonly used substrates like Al2O3, SrTiO 3, and SiO2, have serious chemical compatibility problems. In the latter case, caution should be taken when fabricating thin films. This thesis also describes the discovery of superconductivity at 8 K in the perovskite structure compound MgCNi3. This material is the three-dimensional analogue of the LnNi2B2C family of superconductors, which have Tcs up to 16K. The itinerant electrons in both LnNi2B2C and MgCNi3 are based on partial filling of Ni d-states, which generally leads to ferromagnetism, as is the case in metallic Ni. The very high relative proportion of Ni in MgCNi3 is especially suggestive of the possible importance of magnetic interactions in the superconductivity, and, further, the lower Tc of the three-dimensional compound is contrary to conventional ideas.

  16. Catalytic Reductions and Tandem Reactions of Nitro Compounds Using in Situ Prepared Nickel Boride Catalyst in Nanocellulose Solution.

    Science.gov (United States)

    Prathap, Kaniraj Jeya; Wu, Qiong; Olsson, Richard T; Dinér, Peter

    2017-09-15

    A mild and efficient method for the in situ reduction of a wide range of nitroarenes and aliphatic nitrocompounds to amines in excellent yields using nickel chloride/sodium borohydride in a solution of TEMPO-oxidized nanocellulose in water (0.01 wt %) is described. The nanocellulose has a stabilizing effect on the catalyst, which increases the turnover number and enables low loading of nickel catalyst (0.1-0.25 mol % NiCl2). In addition, two tandem protocols were developed in which the in situ formed amines were either Boc-protected to carbamates or further reacted with an epoxide to yield β-amino alcohols in excellent yields.

  17. Multiple Electron Charge Transfer Chemistries for Electrochemical Energy Storage Systems: The Metal Boride and Metal Air Battery

    Science.gov (United States)

    Stuart, Jessica F.

    The primary focus of this work has been to develop high-energy capacity batteries capable of undergoing multiple electron charge transfer redox reactions to address the growing demand for improved electrical energy storage systems that can be applied to a range of applications. As the levels of carbon dioxide (CO2) increase in the Earth's atmosphere, the effects on climate change become increasingly apparent. According to the Energy Information Administration (EIA), the U.S. electric power sector is responsible for the release of 2,039 million metric tons of CO2 annually, equating to 39% of total U.S. energy-related CO2 emissions. Both nationally and abroad, there are numerous issues associated with the generation and use of electricity aside from the overwhelming dependence on fossil fuels and the subsequent carbon emissions, including reliability of the grid and the utilization of renewable energies. Renewable energy makes up a relatively small portion of total energy contributions worldwide, accounting for only 13% of the 3,955 billion kilowatt-hours of electricity produced each year, as reported by the EIA. As the demand to reduce our dependence on fossils fuels and transition to renewable energy sources increases, cost effective large-scale electrical energy storage must be established for renewable energy to become a sustainable option for the future. A high capacity energy storage system capable of leveling the intermittent nature of energy sources such as solar, wind, and water into the electric grid and provide electricity at times of high demand will facilitate this transition. In 2008, the Licht Group presented the highest volumetric energy capacity battery, the vanadium diboride (VB2) air battery, exceedingly proficient in transferring eleven electrons per molecule. This body of work focuses on new developments to this early battery such as fundamentally understanding the net discharge mechanism of the system, evaluation of the properties and performance of nanoscopic anodic materials in addition to the previously developed macroscopic system, as well as the exploration of a high-energy capacity TiB 2/VB2 composite anode. However, the greatest challenge to this room temperature VB2 primary battery is to develop a means to electrochemically recharge the anodic material (how to reinsert the eleven electrons per molecule that are removed during the battery's discharge). Rechargeable batteries, such as the new molten air battery presented in this thesis, offer a high intrinsic capacity mode for energy storage and overcome problems such as the need for higher energy capacity, cost-effective batteries for a range of electronic, transportation, and large-scale power storage devices. Molten air batteries presented and discussed in this work are viable systems that provide a means to electrochemically recharge the VB2-air battery and deliver large-scale energy storage due to their scalability, location flexibility, construction from readily available resources, and offer increased energy storage capacity for the electric grid. One example is the VB2 molten air battery, which discharges according to: VB 2 + 11/4 O2 → 1/ 2 V2O5 + B2O3 (1). Previously, our group has shown that carbon dioxide can be captured from atmospheric air concentrations at solar efficiencies as high as 50%, and that carbon dioxide emissions associated with the production of several commodities can be electrochemically avoided in by the Solar Thermal Electrochemical Process (STEP). Utilizing this process, the carbon molten air battery relies on carbon dioxide directly from the air: Charging: CO2 (g) → C (solid) + O2 (g) (2) Discharging: C (solid) + O2 (g) → CO2 (g) (3). More specifically, in a molten carbonate electrolyte containing added oxide, such as lithium carbonate with lithium oxide, the four-electron charging reaction, Equation 2, approaches 100% faradic efficiency and can be described as the following two equations: O2- (dissolved) + CO2 (g) → CO 32- (molten) (2a) CO32- (molten) ?→ C (solid) + O2 (g) + O2- (dissolved) (2b). Thus, powered by the oxidation of carbon formed directly from the CO 2 in our earth's atmosphere, the carbon molten air battery is a viable system to provide large-scale energy storage. These batteries are rechargeable and have amongst the highest intrinsic battery storage capacities available. The electron charge transfer chemistry is demonstrated through three examples. These examples utilize iron, carbon, and vanadium diboride as reactive materials, each containing intrinsic volumetric energy capacities of 10,000 Wh/L for Fe to Fe (III), 19,000 Wh/L for C to CO2, and 27,000 Wh/L for VB2 to B2O3 and V2O 5, compared to 6,200 Wh/L for the lithium air battery.

  18. Fluorescence enhancement of samarium (III) perchlorate by 1,10-phenanthroline on Phenylnaphthoylmethyl sulfoxide complex and luminescence mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wen-Xian, E-mail: nmglwx@163.com; Feng, Shu-Yan; Liu, Yu; Zhang, Jing; Xin, Xiao-Dong; Ao, Bo-Yang; Li, Ying-Jie

    2013-11-15

    A novel ligand, Phenylnaphthoylmethyl sulfoxide, was synthesized by a new method. Its novel binary complex, SmL{sub 5}·(ClO{sub 4}){sub 3}·2H{sub 2}O, and the ternary complex, SmL{sub 4}·L′(ClO{sub 4}){sub 3}·2H{sub 2}O, had been synthesized (using Phenylnaphthoylmethyl sulfoxide as the first ligand L, 1,10-phenanthroline as the second ligand L′). The complexes were characterized by element analysis, coordination titration, molar conductivity, IR, TG-DSC, {sup 1}HNMR and UV spectra. Their fluorescence emission mechanism, fluorescence intensities and phosphorescence spectra of the two ligands were also investigated by comparison. Fluorescent spectra illustrated that the ternary rare-earth complex presented stronger fluorescence intensity than the binary rare-earth complex in such material. The strongest characteristic fluorescence emission intensity of the ternary system was 1.81 times as strong as that of the binary system. By the analysis of fluorescence and phosphorescence spectra, it was found that the Phenylnaphthoylmethyl sulfoxide and phen had the advantage to absorb and transfer energy to Sm (III) ions effectively, and then the complexes emitted the characteristic fluorescence of Sm (III) ions. The phosphorescence spectra and fluorescence lifetime of the complexes were also measured. -- Highlights: • A novel ligand, Phenylnaphthoylmethyl sulfoxide, has been synthesized. • Its novel ternary complex and the binary complex have been synthesized. • The fluorescence emission intensity of ternary rare earth complex exhibit obvious enhancement. • The fluorescence emission mechanism and phosphorescence spectra are also investigated.

  19. Polypropylene oil as fuel for solid oxide fuel cell with samarium doped-ceria (SDC)-carbonate as electrolyte

    Science.gov (United States)

    Syahputra, R. J. E.; Rahmawati, F.; Prameswari, A. P.; Saktian, R.

    2017-03-01

    The research focusses on converting polypropylene oil as pyrolysis product of polypropylene plastic into an electricity. The converter was a direct liquid fuel-solid oxide fuel cell (SOFC) with cerium oxide based material as electrolyte. The polypropylene vapor flowed into fuel cell, in the anode side and undergo oxidation reaction, meanwhile, the Oxygen in atmosphere reduced into oxygen ion at cathode. The fuel cell test was conducted at 400 - 600 °C. According to GC-MS analysis, the polypropylene oil consist of C8 to C27 hydrocarbon chain. The XRD analysis result shows that Na2CO3 did not change the crystal structure of SDC even increases the electrical conductivity. The maximum power density is 0.079 mW.cm-2 at 773 K. The open circuite voltage is 0.77 volt. Chemical stability test by analysing the single cell at before and after fuel cell test found that ionic migration occured during fuel cell operation. It is supported by the change of elemental composition in the point position of electrolyte and at the electrolyte-electrode interface

  20. A distribution pattern of cadmium, gadolinium and samarium in Phaseolus vulgaris (L) plants as assessed by dynamic neutron radiography

    Science.gov (United States)

    Kőrösi, Ferenc; Balaskó, Márton; Sváb, Erzsébet

    1999-11-01

    The qualitative and semi-quantitative distributions, presumably apoplast transport patterns for the Gd, Sm and Cd were investigated in the primordial leaf tissues of the bean using dynamic neutron radiography. According to the applied 3D, 2D images and the pixel count distribution histograms of the considered gray levels, peculiar distribution patterns were postulated for the elements. Main and lateral vascular systems for Gd, the cell walls as well as intercellular spaces for Sm and the main leaf vein for Cd assumed to be the apoplast transport spaces and volumes.

  1. Ab initio calculation of the migration free energy of oxygen diffusion in pure and samarium-doped ceria

    Science.gov (United States)

    Koettgen, Julius; Schmidt, Peter C.; Bučko, Tomáš; Martin, Manfred

    2018-01-01

    We have studied the free energy migration barriers Δ F‡ for oxygen diffusion in pure ceria and Sm-doped ceria for the temperatures 300, 700, and 1000 K. We used the density functional theory in the generalized gradient approximation and an additional Hubbard U parameter for the Ce 4 f electronic states. We compare the results for the free energy deduced from three different methods. First, a static harmonic approach is applied in which the temperature dependent vibrational contributions to energy and entropy are deduced from the phonon frequencies of supercells with a fixed volume. Second, a static quasiharmonic approach is used in which a part of the anharmonicity effect is introduced via an implicit dependence of the harmonic frequencies on the thermally expanding cell volume. Third, the free energy barriers are calculated using metadynamics and molecular dynamics in which anharmonicity effects are naturally taken into account. The three methods examined in this study lead to distinctly different results. According to the harmonic approximation, the migration free energy difference Δ F‡ increases with increasing temperature due to an increasing entropic contribution. According to the quasiharmonic approximation, the migration free energy is independent of temperature. Finally, molecular dynamics predicts a thermally induced increase in the migration free energy. We conclude that temperature dependent experimental lattice constants cancel out the increasing entropic contribution with increasing temperature in the static quasiharmonic approach. The full consideration of anharmonicity effects in the metadynamics method again leads to a temperature dependent migration free energy.

  2. Studies on the preparation and stability of samarium-153 propylene diamine tetramethylene phosphonate (PDTMP) complex as a bone seeker

    Energy Technology Data Exchange (ETDEWEB)

    Majali, M.A. E-mail: mythili@magnum.barc.ernet.in; Mathakar, A.R.; Shimpi, H.H.; Banerjee, Sharmila; Samuel, Grace

    2000-12-15

    Propylene diamine tetra methylene phosphonate (PDTMP) was synthesised by modifying a method reported for the synthesis of EDTMP. Complexation of the synthesised phosphonate ligand with {sup 153}Sm was carried out by varying the experimental parameters and the complex was radiochemically characterized. Biodistribution studies showed that the uptake by bone in rats was 2% per g of bone, which was retained up to 48 h. The uptake by other organs was insignificant, except by the liver which showed a slightly higher absorption.

  3. Crystal structure of a samarium(III nitrate chain cross-linked by a bis-carbamoylmethylphosphine oxide ligand

    Directory of Open Access Journals (Sweden)

    Julie A. Stoscup

    2014-10-01

    Full Text Available In the title compound poly[aquabis(μ-nitrato-κ4O,O′:O,O′′tetrakis(nitrato-κ2O,O′{μ4-tetraethyl [(ethane-1,2-diylbis(azanediylbis(2-oxoethane-2,1-diyl]diphosphonate-κ2O,O′}disamarium(III], [Sm2(NO36(C14H30N2O8P2(H2O]n, a 12-coordinate SmIII and a nine-coordinate SmIII cation are alternately linked via shared bis-bidentate nitrate anions into a corrugated chain extending parallel to the a axis. The nine-coordinate SmIII atom of this chain is also chelated by a bidentate, yet flexible, carbamoylmethylphoshine oxide (CMPO ligand and bears one water molecule. This water molecule is hydrogen bonded to nitrate groups bonded to the 12-coordinate SmIII cation. The CMPO ligand, which lies about an inversion center, links neighboring chains along the c axis, forming sheets parallel to the ac plane. Hydrogen bonds between the amide NH group and metal-bound nitrate anions are also present in these sheets. The sheets are packed along the b axis through only van der Waals interactions.

  4. Structure, reactivity, electronic configuration and magnetism of samarium atomic layers deposited on Si(0 0 1) by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Gheorghe, Nicoleta G.; Lungu, George A.; Husanu, Marius A.; Costescu, Ruxandra M.; Macovei, Dan [National Institute of Materials Physics, Atomistilor 105 b, 077125 Magurele-Ilfov (Romania); Teodorescu, Cristian M., E-mail: teodorescu@infim.ro [National Institute of Materials Physics, Atomistilor 105 b, 077125 Magurele-Ilfov (Romania)

    2013-02-15

    The surface structure, interface reactivity, electron configuration and magnetic properties of Sm layers deposited on Si(0 0 1) at various temperatures are investigated by low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS) and magneto-optical Kerr effect (MOKE). It is found that metal Sm is present on samples prepared at low temperature, with an interface layer containing SmSi{sub 2} and Sm{sub 4}Si{sub 3}. When samples are prepared at high temperature, much less metal Sm is found, with an increasing amount of SmSi{sub 2}. Room temperature ferromagnetism is observed for all prepared layers, with a decrease of the saturation magnetization when samples are prepared at high temperature. It is found that ferromagnetism implies mostly a compound with approximate stoichiometry Sm{sub 4}Si{sub 3}. Also, the decrease in the intensity of the XAS 2p{sub 3/2} → 3d white lines with the corresponding increasing amount of SmSi{sub 2} may be explained by assuming a higher occupancy of Sm 5d orbitals (5d{sup 2} configuration), most probably due to hybridation effects.

  5. Calculation and comparison of xenon and samarium reactivities of the HEU, LEU core in the low power research reactor.

    Science.gov (United States)

    Dawahra, S; Khattab, K; Saba, G

    2015-07-01

    Comparative studies for the conversion of the fuel from HEU to LEU in the Miniature Neutron Source Reactor (MNSR) have been performed using the MCNP4C and GETERA codes. The precise calculations of (135)Xe and (149)Sm concentrations and reactivities were carried out and compared during the MNSR operation time and after shutdown for the existing HEU fuel (UAl4-Al, 90% enriched) and the potential LEU fuels (U3Si2-Al, U3Si-Al, U9Mo-Al, 19.75% enriched and UO2, 12.6% enriched) in this paper using the MCNP4C and GETERA codes. It was found that the (135)Xe and (149)Sm reactivities did not reach their equilibrium reactivities during the daily operating time of the reactor. The (149)Sm reactivities could be neglected compared to (135)Xe reactivities during the reactor operating time and after shutdown. The calculations for the UAl4-Al produced the highest (135)Xe reactivity in all the studied fuel group during the reactor operation (0.39 mk) and after the reactor shutdown (0.735 mk), It followed by U3Si-Al (0.34 mk, 0.653 mk), U3Si2-Al (0.33 mk, 0.634 mk), U9Mo-Al (0.3 mk, 0.568 mk) and UO2 (0.24 mk, 0.448 mk) fuels, respectively. Finally, the results showed that the UO2 was the best candidate for fuel conversion to LEU in the MNSR since it gave the lowest (135)Xe reactivity during the reactor operation and after shutdown. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Development of samarium [{sup 32}P] phosphate colloid for radiosynoviorthesis applications: Preparation, biological and preliminary clinical studies experience

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakar, G. [Radiopharmaceuticals Programme, Board of Radiation and Isotope Technology (BRIT), BARC Vashi Complex, Sector-20, Navi Mumbai 400 705 (India)], E-mail: gantipk47@rediffmail.com; Sachdev, Satbir S.; Umamaheswari, S.; Sivaprasad, N.; Bhatia, Manohar H. [Radiopharmaceuticals Programme, Board of Radiation and Isotope Technology (BRIT), BARC Vashi Complex, Sector-20, Navi Mumbai 400 705 (India); Chaudhari, Pradip R. [Laboratory Nuclear Medicine Services, BARC, Mumbai 400 012 (India); Solav, Srikant V. [Spect Lab, Nuclear Medicine Services, Opposite Dinanath Mangeshkar Hospital, Pune 411004 (India)

    2007-12-15

    A new therapeutic radio colloid for radiosynoviorthesis (RS) applications is reported. The method of preparation involves the reaction of SmCl{sub 3} carrier with carrier added [{sup 32}P]H{sub 3}PO{sub 4} in the presence of gelatin. The pure colloid was recovered by dialysis purification leading to radiochemical yield of around 90%. The radiochemical purity of the pure colloid formulated in isotonic saline was over 98%, for the usage period of 14 days, as assessed by paper chromatography. Ninety percent of colloid particles were in the size of 1-10 {mu}m as evident from the laser diffraction particle size analysis, ideally suitable for the intended end use. Animal studies revealed complete retention of the radio colloid in the rabbit knee joint. The results of clinical trials in humans are satisfactory and encouraging, satisfactory retention of the colloid in the knee joint and negligible leakage into the systemic circulation.

  7. Peculiarities of structure state and mechanical characteristics in ion-plasma condensates of quasibinary system borides W2B5-TiB2

    Directory of Open Access Journals (Sweden)

    Sobol O.V.

    2006-01-01

    Full Text Available In order to create high-durable, wear-resistant materials for a wide range of functional applications, comparative investigations of the structure and mechanical characteristics of ion-plasma Ti-W-B nano-crystalline condensates were carried out. The range of condensation rates 0.11÷0.25nm/s was found to be critical for the coatings obtained from the target with 80 vol% W2B5-20 vol% TiB2. Below this, a phase with a cubic lattice (W,TiB0.7…1.2(O,N,C0.3…0.2 formed, while over this range, a solid solution (W,TiB2 with a hexagonal lattice and element composition close to the sputtered target was observed. The structure state of the material changed from cluster-crystalline (under low sputter potentials U=0.6…1.0 kV to textured- crystalline (under U>2.2 kV. Structure perfection improvement with U increase results in higher hardness and elastic modulus of condensates. The conditions of cluster component formation and its effect on hardness and elastic modulus of condensates are discussed. .

  8. Thermionic emission and vaporization behavior of the ternary systems of lanthanum hexaboride containing molybdenum boride, molybdenum diboride, zirconium diboride, gadolinium hexaboride, and neodymium hexaboride

    Science.gov (United States)

    Storms, E. K.

    1983-02-01

    The addition of various compounds to LaB6 did not improve the thermionic emission over that of pure LaB6. This experience and general conclusions, which result by considering the vaporization properties of these and other materials, greatly limit the options available to improve the properties of LaB6 by forming a ternary system. The principles which must be considered, in order to simplify future work, are described.

  9. Effect of double addition of V and Cr on the properties of Mo{sub 2}NiB{sub 2} ternary boride-based cermets

    Energy Technology Data Exchange (ETDEWEB)

    Shiota, Yuusuke; Miyajima, Yuuta; Fujima, Takuya; Takagi, Ken-ichi [Department of Mechanical Engineering, Tokyo City University 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo 158-8557 (Japan)], E-mail: ktakagi@tcu.ac.jp

    2009-06-01

    The effect of double addition of V and Cr on the mechanical properties and microstructure of Mo{sub 2}NiB{sub 2} base cermet was investigated. Total additional amount of V and Cr was fixed to 12.5 mass% and the fraction between the two additives was varied. Transverse rupture strength (TRS) and Rockwell A-scale hardness (HRA) were measured on the cermets and discussed together with their microstructure obtained by X-ray diffraction (XRD) and backscattered electron images (COMP). Addition of 2.5-mass% Cr and 10-mass% V showed the highest mechanical properties. Microstructural analysis revealed that brittle orthoronbic-M{sub 5}B{sub 3} phase was formed in high V fraction. The corrosion resistance of the cermets against hydrochloric acid was superior to that of JIS SUS 304. The resistance against nitric acid decreased with decreasing Cr content and was lower than that of SUS 304.

  10. Diffusional Growth Kinetics Analisys of Fe2B Layers Applied During the Coating Powder-Pack Boriding Process on an AISI 1026 Steel

    Directory of Open Access Journals (Sweden)

    M. Elias-Espinosa

    2015-01-01

    Full Text Available La exigencia de emplear materiales con propiedades avanzadas incluyen la necesidad de aplicar recubrimientos de alta resistencia que alarguen la vida de útil de aceros comerciales, de esta forma, el tratamiento termoquímico de borurización tiene el potencial para cumplir estos requerimientos. En este trabajo de investigación se formula un modelo matemático para analizar la cinética de crecimiento de las capas de 2 Fe B formadas sobre la superficie de un acero AISI 1026. El modelo matemático propuesto se desarrolló en base a la solución de la ecuación de balance de masa de la interface de crecimiento 2 Fe B/Fe para evaluar el coeficiente de difusión del boro a través de las capas de Fe2B en un rango de temperaturas de 1123 a1273 K. En el modelo desarrollado se incluyó el tiempo de incubación del boruro para formar la fase Fe2B. El modelo matemático fue validado con datos experimentales realizados a una temperatura de 1253 K y tiempo de siete horas. Las capas de boruro fueron caracterizadas y analizadas por microscopia óptica y de barrido (se obtuvo un EDS, así como por Difracción de Rayos – X (XRD. Se utilizó la técnica de indentación Daimler-Benz Rockwell-C para evaluar cualitativamente la adherencia de la capa de Fe2B sobre el sustrato (acero AISI 1026. Para usos prácticos y para un espesor determinado, se propuso un diagrama a espesor constante (215 μm el cual es controlado con la variación de la temperatura y tiempo de exposición al recubrimiento. De los resultados obtenidos, se encontró que la energía de activación para el boro en el acero AISI 1026 es igual a 178 kJ mol-1.

  11. Tetrakis(μ-propanoato-κ2O:O′bis[(1,10-phenanthroline-κ2N,N′(propanoato-κ2O,O′samarium(III

    Directory of Open Access Journals (Sweden)

    Chun-Xiang Wang

    2008-01-01

    Full Text Available The title complex, [Sm2(C3H5O26(C12H8N22], is a dinuclear centrosymmetric molecule, in which two crystallographically equivalent Sm atoms, separated by 3.9502 (2 Å, are bridged by four propanoate anions. Each Sm atom is coordinated by two N atoms from one chelating phenanthroline ligand and seven carboxylate O atoms from five propanoate anions, to form a distorted tricapped trigonal prism.

  12. Processing of composites based on NiO, samarium-doped ceria and carbonates (NiO-SDCC as anode support for solid oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Lily Siong Mahmud

    2017-09-01

    Full Text Available NiO-SDCC composites consisting of NiO mixed with Sm-doped ceria (SDC and carbonates (Li2CO3 and Na2CO3 were sintered at different temperatures and reduced at 550 °C. The influence of reduction on structure of the NiO-SDCC anode support for solid oxide fuel cells (SOFCs was investigated. Raman spectra of the NiO-SDCC samples sintered at 500, 600 and 700 °C showed that after reducing at 550 °C NiO was reduced to Ni. In addition, SDC and carbonates (Li2CO3 and Na2CO3 did not undergo chemical transformation after reduction and were still detected in the samples. However, no Raman modes of carbonates were identified in the NiO-SDCC pellet sintered at 1000 °C and reduced at 550 °C. It is suspected that carbonates were decomposed at high sintering temperature and eliminated due to the reaction between the CO32– and hydrogen ions during reduction in humidified gases at 550 °C. The carbonate decomposition increased porosity in the Ni-SDCC pellets and consequently caused formation of brittle and fragile structure unappropriated for SOFC application. Because of that composite NiO-SDC samples without carbonates were also analysed to determine the factors affecting the crack formation. In addition, it was shown that the different reduction temperatures also influenced the microstructure and porosity of the pellets. Thus, it was observed that Ni-SDC pellet reduced at 800 °C has higher electrical conductivity of well-connected microstructures and sufficient porosity than the pellet reduced at 550 °C.

  13. The single cell of low temperature solid oxide fuel cell with sodium carbonate-SDC (samarium-doped ceria) as electrolyte and biodiesel as fuel

    Science.gov (United States)

    Rahmawati, F.; Nuryanto, A.; Nugrahaningtyas, K. D.

    2016-02-01

    In this research NSDC (composite of Na2CO3-SDC) was prepared by the sol-gel method to produce NSDC1 and also by the ceramic method to produce NSDC2. The prepared NSDC then were analyzed by XRD embedded with Le Bail refinement to study the change of characteristic peaks, their crystal structure, and their cell parameters. Meanwhile, the measurement of impedance was conducted to study the electrical conductivity of the prepared materials. A single cell was prepared by coating NSDC-L (a composite of NSDC with Li0.2Ni0.7Cu0.1O2) on both surfaces of NSDC. The NSDC-L was used as anode and cathode. The ionic conductivity of NSDC1 and NSDC2 at 400 oC are 4.1109 x 10-2 S.cm-1 and 1.6231 x 10-2 S.cm-1, respectively. Both electrolytes have ionic conductivity higher than 1 x 10-4 S.cm-1, therefore, can be categorized as good electrolyte [1]. However, the NSDC1 shows electrodeelectrolyte conduction. It indicates the existence of electronic migration from electrolyte- electrode or vice versa. Those may cause a short circuit during fuel cell operation and will reduce the fuel cell performance fastly. The single cell tests were conducted at 300, 400, 500 and 600 °C. The single fuel cell with NSDC1 and NSDC2 as electrolyte show maximum power density at 400 °C with the power density of 3.736 x 10-2 mW.cm-2 and 2.245 x 10-2 mW.cm-2, respectively.

  14. Samarium-neodymium chronology and rubidium-strontium systematics of an Allende calcium-aluminum-rich inclusion with implications for 146Sm half-life

    Science.gov (United States)

    Marks, N. E.; Borg, L. E.; Hutcheon, I. D.; Jacobsen, B.; Clayton, R. N.

    2014-11-01

    Calcium-aluminum-rich inclusions (CAIs) are primitive objects that formed within the protoplanetary disk surrounding the young Sun. Recent Pb-Pb chronologic studies have demonstrated that CAIs are the oldest solar system solids, crystallizing 4567 Ma ago (Amelin et al., 2002; Connelly et al., 2012). The isotope systematics of CAIs therefore provide critical insight into the earliest history of the Solar System. Although Sm-Nd and Rb-Sr geochronometers are highly effective tools for investigating cosmochemical evolution in the early Solar System, previous studies of CAIs have revealed evidence for isotopically disturbed systems. Here we report new age data for Allende CAI Al3S4 derived from both the long-lived (147Sm-143Nd) and short-lived (146Sm-142Nd) isotopic systems. The 147Sm-143Nd chronometer yields an age of 4560 ± 34 Ma that is concordant with 207Pb-206Pb ages for CAIs and indicates that the Sm-Nd system was not significantly disturbed by secondary alteration or nucleosynthetic processes. The slope of the 146Sm-142Nd isochron defines the Solar System initial 146Sm/144Sm of 0.00828 ± 0.00044. This value is significantly different from the value of 0.0094 determined by Kinoshita et al. (2012). Ages recalculated from all published 146Sm-142Nd isochron data using the traditional 103 Ma half-life and the initial 146Sm/144Sm value determined here closely match Pb-Pb and 147Sm-143Nd ages determined on the same samples. In contrast, ages recalculated using the 68 Ma half-life determined by Kinoshita et al. (2012) and either of the initial 146Sm/144Sm values are often anomalously old. This is particularly true for the youngest samples with 146Sm-142Nd isochron ages that are most sensitive to the choice of 146Sm half-life used in the age calculation. In contrast to the Sm-Nd isotope system, the Rb-Sr system is affected by alteration but yields an apparent isochron with a slope corresponding to a much younger age of 4247 ± 110 Ma. Although the Rb-Sr system in CAIs appears to be disturbed, the initial 87Sr/86Sr value determined from the isochron is 0.698942 ± 0.000008, and closely approximates estimates of the initial Solar System value. Although this isochron may be a mixing line, it might also record alteration on the Allende parent body in which Rb was added to the Al3S4 CAI that was initially largely devoid of Rb.

  15. Anthropogenic dissolved and colloid/nanoparticle-bound samarium, lanthanum and gadolinium in the Rhine River and the impending destruction of the natural rare earth element distribution in rivers

    Science.gov (United States)

    Kulaksız, Serkan; Bau, Michael

    2013-01-01

    The strong increase in the consumption of rare earth elements (REE) in high-tech products and processes is accompanied by increasing amounts of REE released into the environment. Following the first report of Gd contamination of the hydrosphere in 1996, anthropogenic Gd originating from contrast agents has now been reported worldwide from river and estuarine waters, coastal seawater, groundwater and tap water. Recently, microcontamination with La, that is derived from a point source where catalysts for petroleum refining are produced, has been detected in the Rhine River in Germany and the Netherlands. Here we report the occurrence of yet another REE microcontamination of river water: in addition to anthropogenic Gd and La, the Rhine River now also shows significant amounts of anthropogenic Sm. The anthropogenic Sm, which enters the Rhine River north of Worms, Germany, with the same industrial wastewater that carries the anthropogenic La, can be traced through the Middle and Lower Rhine to the Netherlands. At Leverkusen, Germany, some 250 km downstream from the point source at Worms, anthropogenic Sm still contributes up to 87% of the total dissolved Sm concentration of the Rhine River. Results from ultrafiltration suggest that while the anthropogenic Gd is not particle-reactive and hence exclusively present in the truly dissolved REE pool (Worms get close to and well-above, respectively, the levels at which ecotoxicological effects have been documented. Because of the increasing use of REE and other formerly "exotic" trace elements in high-tech applications, these critical metals have now become emerging contaminants that should be monitored, and it appears that studies of their biogeochemical behavior in natural freshwaters might soon no longer be possible.

  16. Ultra-Sensitive Nano Optical Sensor Samarium-Doxycycline Doped in Sol Gel Matrix for Assessment of Glucose Oxidase Activity in Diabetics Disease.

    Science.gov (United States)

    Tharwat, Marwa M; Attia, M S; Alghamdi, M S; Mahros, Amr M

    2017-07-11

    A low cost and very sensitive method for the determination of the activity of glucose oxidase enzyme in different diabetics serum samples was developed. The method based on the assessment of the H2O2 concentration produced from the reaction of the glucose oxidase (GOx) enzyme with glucose as substrate in the serum of diabetics patients by nano optical sensor Sm-doxycycline doped in sol gel matrix. H2O2 enhances the luminescence intensity of all bands of the nano Sm-doxycycline complex [Sm-(DC)2](+) doped in sol-gel matrix, especially the 645 nm band at λex = 400 nm and pH 7.0 in water. The influence of the different analytical parameters that affect the luminescence intensity of the nano optical sensor, e.g. pH, H2O2 concentration and foreign ions concentrations were studied. The remarkable enhancement of the luminescence intensity of nano optical sensor [Sm-(DC)2](+) complex in water at 645 nm by the addition of various concentrations of H2O2 was successfully used as an optical sensor for the assessment of the activity of the glucose oxidase enzyme in different diabetics serum samples. The calibration plot was achieved over the activity range 0.1-240 U/L with a correlation coefficient of 0.999 and a detection limit of 0.05 U/L.

  17. Effect of Mg doping and sintering temperature on structural and morphological properties of samarium-doped ceria for IT-SOFC electrolyte

    Science.gov (United States)

    Ahmad, Syed Ismail; Mohammed, Tasneem; Bahafi, Amal; Suresh, Madireddy Buchi

    2017-06-01

    Samples of Sm and Mg co-doped ceria electrolyte of Ce1- x Sm x- y Mg y O2- δ ( x = 0.2; y = 0.00, 0.05, 0.1, 0.15, and 0.175) were synthesized by sol-gel process. The prepared samples were sintered at 1100 and 1400 °C for 4 h. The bulk densities were measured by Archimedes method. XRD measurements indicate that the synthesized samples were in single-phase cubic fluorite structure (space group Fm3m). The cell parameters decrease with the concentration of Mg, and 2 θ values slightly shift towards right. The particle sizes obtained were between 7.14 and 17.44 nm. The sintered sample achieved 95% of theoretical density. FTIR spectra of samples sintered at 1400 °C indicates weak interactions between 3550-3400 cm-1 and 1600-1300 cm-1 are attributed to O-H stretching modes and strong bonds 850-450 cm-1 are assigned to characteristic Ce-O vibrations. The surface morphology and chemical composition were analyzed by SEM and EDS, SEM micrographs show spherical faceted grains, and the samples were crack free, dense material with some pores on surface which are inconsistent with density results. The average grain size obtained was 0.5 μm. Particle size obtained by TEM was in agreement with that obtained by XRD. The high-density ceria co-doped ceramic can be used as electrolyte in SOFC.

  18. Synthesis, spectroscopic, thermal and antimicrobial studies of neodymium(III) and samarium(III) complexes derived from tetradentate ligands containing N and S donor atoms

    Science.gov (United States)

    Ain, Qurratul; Pandey, S. K.; Pandey, O. P.; Sengupta, S. K.

    2015-04-01

    Trivalent lanthanide complexes of the type [Ln(L)Cl(H2O)2] (where Ln = Nd(III) or Sm(III) and LH2 = Schiff bases derived by the condensation of 3-(phenyl/substitutedphenyl)-4-amino-5-mercapto-1,2,4-triazole with diacetyl/benzil) have been synthesized by the reactions of anhydrous lanthanide(III) chloride with Schiff bases in methanol. The structures of the complexes have been proposed on the basis of elemental analysis, electrical conductance, magnetic moment, spectroscopic measurements (IR, 1H, 13C NMR and UV-vis spectra) and X-ray diffraction studies. The spectral data reveal that the Schiff base ligands behave as dibasic tetradentate chelating agents having coordination sites at two thiol sulfur atoms and two azomethine nitrogen atoms. The presence of coordinated water in metal complexes was confirmed by thermal and IR data of the complexes. All the Schiff bases and their metal complexes have also been screened for their antibacterial activity against Bacillus subtilis, Staphylococcus aureus and antifungal activities against Aspergillus niger, Curvularia pallescens and Colletotrichum capsici.

  19. Logarithmic temperature dependence of samarium ion valence in the heavy-fermion S mxL a1 -xO s4S b12

    Science.gov (United States)

    Fushiya, Kengo; Miyazaki, Ryoichi; Higashinaka, Ryuji; Yamada, Akira; Mizumaki, Masaichiro; Tsutsui, Satoshi; Nitta, Kiyofumi; Uruga, Tomoya; Suemitsu, Bunya; Sato, Hideyuki; Aoki, Yuji

    2015-08-01

    We have measured x-ray absorption spectra at the Sm L3 edge to investigate the Sm-ion valence of (S mxL a1 -x) O s4S b12 , in which field-insensitive heavy-fermion behavior appears at low temperatures for x =1 . It has been found that the Sm-ion valance shifts to 2 + with La ion substitution; from v =+2.78 (x =1 ) to v =+2.73 (x =0.2 ) at 10 K. For all x investigated, its temperature dependence shows a logT behavior, indicating that the valence change is caused by "an unconventional Kondo effect" associated with Sm 4 f -electron charge degrees of freedom. Almost x independence of "the associated Kondo temperature" (T˜K=56 ±10 K ) indicates that the Kondo effect has a local nature, attributable to the cage structure of the filled skutterudite.

  20. Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water

    Energy Technology Data Exchange (ETDEWEB)

    Merschel, Gila, E-mail: g.merschel@jacobs-university.de; Bau, Michael

    2015-11-15

    High-technology metals — such as the rare earth elements (REE) — have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. - Highlights: • Corbicula fluminea shells are bioarchives of dissolved geogenic REE in rivers. • Anthropogenic La and Sm in the Rhine River are bioavailable, hence incorporated. • Anthropogenic Gd from contrast agents is not incorporated, i.e. not bioavailable. • REE concentrations in Corbicula shells decrease with increasing size, i.e. age.

  1. Mechanically induced strong red emission in samarium ions doped piezoelectric semiconductor CaZnOS for dynamic pressure sensing and imaging

    Science.gov (United States)

    Wang, Wei; Peng, Dengfeng; Zhang, Hanlu; Yang, Xiaohong; Pan, Caofeng

    2017-07-01

    Piezoelectric semiconductor with optical, electrical and mechanical multifunctions has great potential applications in future optoelectronic devices. The rich properties and applications mainly encompass the intrinsic structures and their coupling effects. Here, we report that lanthanide ions doped piezoelectric semiconductor CaZnOS:Sm3+ showing strong red emission induced by dynamic mechanical stress. Under moderate mechanical load, the doped piezoelectric semiconductor exhibits strong visible red emission to the naked eyes even under the day light. A flexible dynamic pressure sensor device is fabricated based on the prepared CaZnOS:Sm3+ powders. The mechanical-induced emission properties of the device are investigated by the optical fiber spectrometer. The linear characteristic emissions are attributed to the 4G5/2→6H5/2 (566 nm), 4G5/2→6H7/2 (580-632 nm), 4G5/2→6H9/2 (653-673 nm) and 4G5/2→6H11/2 (712-735 nm) f-f transitions of Sm3+ ions. The integral emission intensity is proportional to the value of applied pressure. By using the linear relationship between integrated emission intensity and the dynamic pressure, the real-time pressure distribution is visualized and recorded. Our results highlight that the incorporation of lanthanide luminescent ions into piezoelectric semiconductors as smart materials could be applied into the flexible mechanical-optical sensor device without additional auxiliary power, which has great potential for promising applications such as mapping of personalized handwriting, smart display, and human machine interface.

  2. Investigation of oxidative coupling of methane over bismuth oxychloride, samarium chloride, or manganese chloride supported on lithium carbonate-magnesia systems

    Energy Technology Data Exchange (ETDEWEB)

    Khan, A.Z.; Ruckenstein, E. (State Univ. of New York, Buffalo, NY (United States))

    1992-11-01

    The magnesia-supported bismuth oxychloride with lithium carbonate present is significantly more effective and stable with time-on-stream than the unsupported or supported systems free of Li[sub 2]CO[sub 3] in the oxidative coupling of methane at 750[degrees]C, P[sub CH[sub 4

  3. Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water.

    Science.gov (United States)

    Merschel, Gila; Bau, Michael

    2015-11-15

    High-technology metals - such as the rare earth elements (REE) - have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Samario-153-Lexidronam (EDTMP) en el tratamiento de las metástasis óseas Samarium-153-Lexidronam (EDTMP) for the management of bone metastases

    OpenAIRE

    F. Torre; C. Gómez-Vega; A. Callejo; J. Genolla

    2004-01-01

    Las metástasis óseas son una complicación frecuente en pacientes neoplásicos, en este sentido, el tejido óseo ocupa el tercer lugar de todos los órganos y sistemas con metástasis después del pulmón e hígado. Aproximadamente un 75% de los enfermos con metástasis óseas sufrirán dolor, siendo estas la causa más frecuente de dolor en pacientes con cáncer. El dolor óseo aumenta con los movimientos y a la presión, limitando la autonomía del enfermo y su calidad de vida. El tratamiento incluye vario...

  5. Morphology and orientation of β-BaB{sub 2}O{sub 4} crystals patterned by laser in the inside of samarium barium borate glass

    Energy Technology Data Exchange (ETDEWEB)

    Nishii, Akihito; Shinozaki, Kenji; Honma, Tsuyoshi; Komatsu, Takayuki, E-mail: komatsu@mst.nagaokaut.ac.jp

    2015-01-15

    Nonlinear optical β-BaB{sub 2}O{sub 4} crystal lines (β-BBO) were patterned in the inside of 8Sm{sub 2}O{sub 3}–42BaO–50B{sub 2}O{sub 3} glass by irradiations of continuous-wave Yb:YVO{sub 4} lasers with a wavelength of 1080 nm (power: P=0.8–1.0 W, scanning speed: S=0.2–2.5 μm/s), in which the laser focal position was moved gradually from the surface to the inside. The morphology, size, and orientation of β-BBO crystals were examined from polarization optical microscope and birefringence imaging observations. It was demonstrated that c-axis oriented β-BBO crystals with long lengths (e.g., 20 mm) were patterned in the inside of the glass. The morphology of β-BBO in the cross-section of lines was a rectangular shape with rounded corners, and the volume of β-BBO formed increased with increasing laser power and with decreasing laser scanning speed. The maximum depth in the inside from the surface for β-BBO patterning increased with increasing laser power, e.g., D{sub max}∼100 μm at P=0.8 W, D{sub max}∼170 μm at P=0.9 W, and D{sub max}∼200 μm at P=1 W. The present study proposes that the laser-induced crystallization opens a new door for applied engineering in glassy solids. - Graphical abstract: This figure shows the POM photographs for β-BaB{sub 2}O{sub 4} crystal lines patterned by cw Yb:YVO{sub 4} fiber laser irradiations with a laser power of P=0.8 W and a laser scanning speed S=2 μm/s in the glass. The laser focal point was moved gradually from the surface into the inside. The results shown in Fig. 1 demonstrate that it is possible to pattern highly oriented β-BaB{sub 2}O{sub 4} crystals even in the inside of glasses. - Highlights: • β-BaB{sub 2}O{sub 4} crystal lines were patterned in the inside of a glass by lasers. • Laser focal position was moved gradually from the surface to the inside. • Birefringence imaging was observed. • Morphology, size, and orientation of crystals were clarified. • Crystal lines with long lengths (e.g., 20 mm) were patterned at the depth of 200 μm.

  6. Advanced Cathodes for Next Generation Electric Propulsion Technology

    Science.gov (United States)

    2008-03-01

    28 Boride Cathodes...45 Figure 15. Molybdenum Hollow Cathode Tube .............................................................. 46...CeB6 as a hollow cathode electron emitter. Additionally, all work in the US published on boride hollow cathodes are for high-current applications

  7. On the Nucleation and Growth of Alpha-Ti Off of TiB Precipitates (PREPRINT)

    Science.gov (United States)

    2010-01-01

    the aluminum and oxygen are enriched in α-Ti phase and depleted in the boride . In contrast, the molybdenum and niobium are enriched in the boride ...that a dispersion of thermally stable titanium- boride particles, formed by trace boron additions, was effective in restricting the grain growth...reinforced by the TiB phase [6-13]. The boride particles act as the pinning sites for the grain boundaries. In the TiB reinforced Ti-6Al-4V alloy

  8. 10 CFR Appendix C to Part 20 - Quantities 1 of Licensed Material Requiring Labeling

    Science.gov (United States)

    2010-01-01

    ... Samarium-151 10 Samarium-153 100 Samarium-155 1,000 Samarium-156 1,000 Europium-145 100 Europium-146 100 Europium-147 100 Europium-148 10 Europium-149 100 Europium-150 (12.62h) 100 Europium-150 (34.2y) 1 Europium-152m 100 Europium-152 1 Europium-154 1 Europium-155 10 Europium-156 100 Europium-157 100 Europium-158 1...

  9. An experiment using neutron activation analysis and a rare earth element to mark cotton plants and two insects that feed on them

    Energy Technology Data Exchange (ETDEWEB)

    Showler, Allan T. [USDA-ARS IFNRRU, Kika de la Garza Subtropical Agricultural Research Center, 2413 East Highway 83, Weslaco, TX 78596 (United States)]. E-mail: ashowler@weslaco.ars.usda.gov; James, William D. [Elemental Analysis Laboratory, 3144 Texas A and M University, College Station, TX 77843-3144 (United States); Armstrong, John S. [USDA-ARS BIRU, Kika de la Garza Subtropical Agricultural Research Center, 2413 East Highway 83, Weslaco, TX 78596 (United States); Westbrook, John K. [USDA-ARS APMRU, 2771 F and B Road, College Station, TX 77845-4966 (United States)

    2006-08-15

    Studies on insect dispersal and other behaviors can benefit from using markers that will not alter flight and fitness. Rare earth elements, such as samarium (Sm), have been used as ingested markers of some insects and detected using neutron activation analysis (NAA). In this study, samarium nitrate hexahydrate was mixed into artificial diet for boll weevils, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), at different dosages and in water used to irrigate cotton, Gossypium hirsutum L. Samarium was detected in adult boll weevils fed on the samarium-labeled diet, but not after 5 or 10 days of being switched to non-labeled diet, even if the insects were given labeled diet for as long as 7 consecutive days. Introduced in irrigation water, 1% samarium (m/m) was detectable in cotton squares and leaf tissue. However, boll weevil adults fed samarium-labeled squares did not retain detectable levels of samarium, nor did boll weevil adults reared to adulthood from samarium-labeled squares. Fourth instar beet armyworms, Spodoptera exigua (Huebner) (Noctuidae: Lepidoptera), fed on samarium-labeled cotton leaves obtained enough samarium for NAA detection, but adult moths reared from them did not have detectable amounts of samarium. Although samarium can be useful as a marker when insects are presented with a continuous pulse of the label, elements that are assimilated by the insect would be more useful if a continuous infusion of the marker cannot be provided.

  10. BORONIZING OF STEEL

    OpenAIRE

    ULUKÖY, Arzum; CAN, Ahmet Çetin

    2006-01-01

    Boride layer has many advantages in comparison with traditional hardening methods. The boride layer has high hardening value and keeps it's hardeness at high temperatures, and it also shows favorible properties, such as the resistance to wear, oxidation and corrosion. The process can be applied at variety of materials, for instance steel, cast iron, cast steel, nickel and cobalt alloys and cermets. In this rewiew, boronizing process properties, boride layer on steel surfaces and specification...

  11. An Attempt to Develop the Methodology of Examining the Boron Content in Construction Materials with the Use of Eds Method

    Directory of Open Access Journals (Sweden)

    Popławski M.

    2015-04-01

    Full Text Available Borided layers are mainly produced during the process of heat-chemical treatment as a result of reactive diffusion of boron inside the material. The borided layers are particularly useful in difficult exploitation conditions. Generally, the borided layers are characterized by the increased hardness, heat resistance and good corrosion resistance. It is commonly known that the major disadvantage of X-ray microanalysis with EDS method is the difficulty in light elements analysis such as boron.

  12. Quantitative Electron-Excited X-Ray Microanalysis of Borides, Carbides, Nitrides, Oxides, and Fluorides with Scanning Electron Microscopy/Silicon Drift Detector Energy-Dispersive Spectrometry (SEM/SDD-EDS) and NIST DTSA-II.

    Science.gov (United States)

    Newbury, Dale E; Ritchie, Nicholas W M

    2015-10-01

    A scanning electron microscope with a silicon drift detector energy-dispersive X-ray spectrometer (SEM/SDD-EDS) was used to analyze materials containing the low atomic number elements B, C, N, O, and F achieving a high degree of accuracy. Nearly all results fell well within an uncertainty envelope of ±5% relative (where relative uncertainty (%)=[(measured-ideal)/ideal]×100%). Quantification was performed with the standards-based "k-ratio" method with matrix corrections calculated based on the Pouchou and Pichoir expression for the ionization depth distribution function, as implemented in the NIST DTSA-II EDS software platform. The analytical strategy that was followed involved collection of high count (>2.5 million counts from 100 eV to the incident beam energy) spectra measured with a conservative input count rate that restricted the deadtime to ~10% to minimize coincidence effects. Standards employed included pure elements and simple compounds. A 10 keV beam was employed to excite the K- and L-shell X-rays of intermediate and high atomic number elements with excitation energies above 3 keV, e.g., the Fe K-family, while a 5 keV beam was used for analyses of elements with excitation energies below 3 keV, e.g., the Mo L-family.

  13. A Study of Solar Thermal Propulsion System Enhancement via Thermal Storage and Thermal-electric Conversion

    Science.gov (United States)

    2010-03-24

    material. Molybdenum has a thermal conductivity of 138 W/mK, while rheniums is much lower at 39.6 W/mK 2 . Zirconium Boride (ZrB2) and Hafnium Boride ...14,000 Iridium 77 2739 213 147 $42,000 Niobium 41 2750 323 53.7 $170 Molybdenum 42 2896 390 138 $100 The materials listed in Table 1 do not...this paper, several materials with melting points above 3000 K are boride compounds and several of those that are not borides contain elements which

  14. BORONIZING OF STEEL

    Directory of Open Access Journals (Sweden)

    Arzum ULUKÖY

    2006-02-01

    Full Text Available Boride layer has many advantages in comparison with traditional hardening methods. The boride layer has high hardening value and keeps it's hardeness at high temperatures, and it also shows favorible properties, such as the resistance to wear, oxidation and corrosion. The process can be applied at variety of materials, for instance steel, cast iron, cast steel, nickel and cobalt alloys and cermets. In this rewiew, boronizing process properties, boride layer on steel surfaces and specifications and the factors that effect boride layer are examined

  15. Obtention of Samarium and Gadolinium concentrates by solvent extraction using mono-2-ethylhexyl ester of 2-ethylhexyl phosphonic acid; Obtencao de concentrados de samario e gadolinio via extracao por solventes com o ester mono-2-etilhexil do acido 2-etilhexilfosfonico

    Energy Technology Data Exchange (ETDEWEB)

    Miranda Junior, Pedro

    1996-07-01

    The rare earth chlorides solution employed in this study, which is constituted by medium and heavy fractions, is derived from monazite processing accomplished by NUCLEMON-Mineroquimica (SP). This solution shows an acidity about 1.18 M and 189 g/L of rare earth oxides, containing as main constituents: Sm(34.55%), Gd(23.85%), Dy (6.82%), and Y (24.45%). It was used, as organic phase, 2-ethylhexyl phosphonic acid, mono-2-ethylhexylester diluted to 1 M in isododecane. (author)

  16. Poly(dl)lactic acid/polyglycolic acid/iron and poly(dl)lactic acid/polyglycolic acid/samarium cobalt composites for use as a delivery mechanism for magnetically directed chondrogenesis

    Science.gov (United States)

    Oppermann, Dean Alan

    Magnetically directed chondrogenesis (MDC) is a fundamental approach to articular cartilage repair. In MDC a magnet is implanted into the subchondral trabecular bone underlying a cartilage defect and used to attract chondrocytes, magnetically tagged with Fe nanoparticles, to the defect site. Pilot studies by Halpern, Crimp and Grande, using solid neodymium (Nd) magnets, indicated optimistic results by producing a hyaline-like articular cartilage after 8 weeks implantation. Since solid Nd magnets introduce long-term biocompatibility issues, the focus of this dissertation was to develop P(dl)A/PGA/Fe and P(dl)A/PGA/SmCo 5 implants for use in MDC. The effect of implant porosity, implant composition and magnetic material (Fe or SmCo5) on the initial and degraded magnetic properties were evaluated. The biocompatibility of P(dl)A/PGA/Fe implants were investigated by implantation into New Zealand white rabbits for 8 weeks. The effect of hydrogen peroxide (H2O2) and ethylene oxide (EO) sterilization techniques on the molecular weight and chemical structure of P(dl)A/PGA polymers were evaluated using gel permeation chromatography and Fourier transform infrared spectroscopy. The effect of implant morphology, size and number on the von Mises stress in the trabecular bone surrounding the implant was evaluated using a finite element model. In general, SmCo5 implants resulted in higher magnetic fields initially and after 8 weeks of degradation than comparable Fe implants. Increases in magnetic field strength were achieved by increasing the volume fraction of magnetic material and by increasing the PGA concentration. The magnetic field strength degradation rate decreased with increases in volume fraction of magnetic material and increases in PLA concentration. Implantation studies indicated that 50/50 P(dl)A/PGA were more bioactive than 75/25 P(dl)A/PGA with an increased cellular response that is specific to bone growth. The compressive strength and elastic modulus of porous implants were comparable to trabecular bone, and the compressive strength and elastic modulus of solid implants was higher than trabecular bone but less than cortical bone. Finite element modeling showed that the implantation of solid and porous P(dl)A/PGA/Fe implants did not significantly increase the von Mises stress concentration adjacent to the implant. The von Mises stress surrounding porous implants was higher than the solid implants which predicts faster bone remodeling. Comparing single implants to multiple implants indicated a significant decrease in von Mises stress between the implants. This would predict bone resorption in that area. H2O2 sterilization resulted in a gradual decrease in the molecular weight of P(dl)A/PGA polymers that was a result of hydrolytic scission of the ester bonds present between the individual monomers. The polymers were less affected by EO sterilization with only the 75/25 P(dl)A/PGA, indicating a decrease in molecular weight. From these results, it was concluded that solid 50/50 P(dl)A/PGA/SmCo 5 implants that span the entire width of the cartilage defect should be used to optimize the attraction potential and bioactivity of the implant. Also ethylene oxide, which caused less premature implant degradation, should be used for sterilization.

  17. Fabrication of a new samarium(III) ion-selective electrode based on 3-{l_brace}[2-oxo-1(2h)-acenaphthylenyliden]amino{r_brace}-2-thioxo -1,3-thiazolidin-4-one

    Energy Technology Data Exchange (ETDEWEB)

    Zamani, Hassan Ali [Islamic Azad University, Quchan (Iran, islamic Republic of). Quchan Branch. Dept. of Chemistry]. E-mail: haszamani@yahoo.com; Ganjali, Mohammad Reza [Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of). Endocrine and Metabolism Research Center; Adib, Mehdi [University of Tehran, Tehran (Iran, Islamic Republic of). Faculty of Chemistry. Center of Excellence in Electrochemistry

    2007-07-01

    This paper introduces the development of an original PVC membrane electrode, based on 3-{l_brace}[2-oxo-1(2H)-acenaphthylenyliden]amino{r_brace}-2-thioxo-1,3-thiazolidin-4-one (ATTO) which has revealed to be a suitable carrier for Sm{sup 3+} ions. The resulting data illustrated that the electrode shows a Nernstian slope of 19.3 {+-} 0.6 mV per decade for Sm{sup 3+} ions over a broad working concentration range of 1.0 X 10{sup -6} to 1.0 X 10{sup -1} mol L{sup -1}. The lower detection limit was found to be equal to (5.5{+-} 0.3) X 10{sup -7} mol L{sup -}'1 in the pH range of 3.5-7.5, and the response time was very short ({approx}10 s). The potentiometric sensor displayed good selectivities for a number of cations such as alkali, alkaline earth, transition and heavy metal ions. (author)

  18. BASIC RESEARCH ON THE SEPARATION OF SCANDIUM YTTRIUM, AND THE RARE EARTHS BY SOLVENT EXTRACTION.

    Science.gov (United States)

    RARE EARTH ELEMENTS, * SOLVENT EXTRACTION ), (*CHELATE COMPOUNDS, RARE EARTH ELEMENTS), PURIFICATION, ATOMIC SPECTROSCOPY, SCANDIUM, YTTRIUM, PRASEODYMIUM, SAMARIUM, EUROPIUM, GADOLINIUM, TERBIUM, FLUORINE COMPOUNDS, KETONES

  19. Mechanochemical synthesis and characterization of pure Co2B ...

    Indian Academy of Sciences (India)

    3Department of Industrial Design Engineering, Gazi University, Ankara 06500, Turkey. MS received 5 January 2016; accepted 2 February 2016. Abstract. Cobalt boride (Co2B) is a significant transition metal boride having a wide range of usage area due to its high oxidation, abrasion and corrosion resistance as well as its ...

  20. Mechanochemical synthesis and characterization of pure Co2B ...

    Indian Academy of Sciences (India)

    Cobalt boride (Co 2 B) is a significant transition metal boride having a wide range of usage area due to its high oxidation, abrasion and corrosion resistance as well as its superior electrochemical, magnetic and anisotropicproperties. In this study, pure Co2B nanocrystals were synthesized with Co, B 2 O 3 and Mg as starting ...

  1. Assessment of Non-Traditional Isotopic Ratios by Mass Spectrometry for Analysis of Nuclear Activities

    Science.gov (United States)

    2016-03-01

    distinguish between commercial nuclear reactor fuel cycles, fuel cycles for weapons grade plutonium , and products from nuclear weapons explosions. Methods will...Isotopic ratios will be calculated for radionuclides produced in commercial nuclear reactor fuel cycles, fuel cycles for weapons grade plutonium , and... chemistry for analysis of samarium. The chemical form of samarium required for analysis varies for different mass spectrometry techniques

  2. Methods of repairing a substrate

    Science.gov (United States)

    Riedell, James A. (Inventor); Easler, Timothy E. (Inventor)

    2011-01-01

    A precursor of a ceramic adhesive suitable for use in a vacuum, thermal, and microgravity environment. The precursor of the ceramic adhesive includes a silicon-based, preceramic polymer and at least one ceramic powder selected from the group consisting of aluminum oxide, aluminum nitride, boron carbide, boron oxide, boron nitride, hafnium boride, hafnium carbide, hafnium oxide, lithium aluminate, molybdenum silicide, niobium carbide, niobium nitride, silicon boride, silicon carbide, silicon oxide, silicon nitride, tin oxide, tantalum boride, tantalum carbide, tantalum oxide, tantalum nitride, titanium boride, titanium carbide, titanium oxide, titanium nitride, yttrium oxide, zirconium boride, zirconium carbide, zirconium oxide, and zirconium silicate. Methods of forming the ceramic adhesive and of repairing a substrate in a vacuum and microgravity environment are also disclosed, as is a substrate repaired with the ceramic adhesive.

  3. Borlanmış AISI 5140 ve AISI 420 Çeliklerinin Difüzyon ve Adhezyon Davranışlarının İncelenmesi (015701) (1-8)

    OpenAIRE

    BARUT, Nusrettin; YAVUZ, Demet; KAYALI, Yusuf

    2015-01-01

    In this study, AISI 5140 steel and AISI 420 stainless steel were pack borided at 1123, 1173 and 1223 K for retention times of 2, 4 and 6 h. The morphology of the boride layers formed on the steel surfaces as a result of the experiments was investigated by optical microscopy. The hardness values were measured by a micro-hardness device and the phases formed on the layer were determined by the XRD method. The XRD analysis revealed that FeB, Fe2B, CrB and MnB phases had formed on the boride laye...

  4. The Critical Technologies Project Executive Summary

    Science.gov (United States)

    1981-01-01

    Materials with the Not covered Chalcopyrite Structure 7.8.23 Rare Earth- Transition Metal Permanent Not covered I Magnets (exanple: samarium cobalt and... Transition Metal Permanent - Magnets (example: samarium cobalt I and substituted samarium cobalt) New 7.8.24 Gadolinium Gallium Garnet (GGG) - - and...III T i mm~ 1.W 8 Chwn..cal Poesse Maclw Tools 1110 1129. 1131 133 1142 0 F -~, oO 16.qm P c Metals 1145, 1203, 1236 4203 1365 00, awm.wq *4 1303 1311

  5. sup 8 sup 9 Sr and sup 1 sup 5 sup 3 Sm-EDTMP therapy of disseminated skeletal metastasis

    CERN Document Server

    Zhang Jun Ning; Zhu Shou Peng

    2001-01-01

    A retrospective analysis was performed on 72 patients with disseminated skeletal metastasis to evaluate the effect of strontium-89 or samarium-153 EDTMP therapy. There existed 87.88% of clinical response, 12.12% of no response in the group treated with strontium-89 as compared with 90.24% of clinical response, 9.76% no response in one treated with samarium-153 EDTMP; and there were no correlation between the treatment results and the amounts of isotopes administrated. The results suggest that strontium-89 or samarium-153 EDTMP therapy is a method of first choice in the palliative treatment for disseminated skeletal metastasis

  6. Chemical Routes to Ceramics With Tunable Properties and Structures

    National Research Council Canada - National Science Library

    Sneddon, Larry G

    2006-01-01

    .... Research was focused on the development of new precursor routes to a number of ultra high temperature ceramics, including hafnium and zirconium -boride, -carbide and -nitride materials, and on the...

  7. EVALUATION OF THERMAL PROTECTIVE SYSTEMS FOR ADVANCED AEROSPACE VEHICLES. VOLUME II: APPENDICES.

    Science.gov (United States)

    AEROSPACE CRAFT, TABLES(DATA), GRAPHICS, OXIDES, BERYLLIUM, HAFNIUM COMPOUNDS, SPINEL, ZIRCONIUM COMPOUNDS, NITRIDES, CARBIDES, BORIDES , SILICIDES...GRAPHITE, NIOBIUM, MOLYBDENUM , TANTALUM, TUNGSTEN, THERMAL PROPERTIES, THERMAL PROPERTIES, SPECIFIC HEAT.

  8. Ceramic material suitable for repair of a space vehicle component in a microgravity and vacuum environment, method of making same, and method of repairing a space vehicle component

    Science.gov (United States)

    Riedell, James A. (Inventor); Easler, Timothy E. (Inventor)

    2009-01-01

    A precursor of a ceramic adhesive suitable for use in a vacuum, thermal, and microgravity environment. The precursor of the ceramic adhesive includes a silicon-based, preceramic polymer and at least one ceramic powder selected from the group consisting of aluminum oxide, aluminum nitride, boron carbide, boron oxide, boron nitride, hafnium boride, hafnium carbide, hafnium oxide, lithium aluminate, molybdenum silicide, niobium carbide, niobium nitride, silicon boride, silicon carbide, silicon oxide, silicon nitride, tin oxide, tantalum boride, tantalum carbide, tantalum oxide, tantalum nitride, titanium boride, titanium carbide, titanium oxide, titanium nitride, yttrium oxide, zirconium diboride, zirconium carbide, zirconium oxide, and zirconium silicate. Methods of forming the ceramic adhesive and of repairing a substrate in a vacuum and microgravity environment are also disclosed, as is a substrate repaired with the ceramic adhesive.

  9. General Information about Osteosarcoma and Malignant Fibrous Histiocytoma of Bone

    Science.gov (United States)

    ... providers who are experts in treating cancer in children. Treatment for osteosarcoma or malignant fibrous histiocytoma may cause side effects. Four types of standard treatment are used: Surgery Chemotherapy Radiation therapy Samarium New types of treatment are ...

  10. Treatment Option Overview (Osteosarcoma and Malignant Fibrous Histiocytoma of Bone)

    Science.gov (United States)

    ... providers who are experts in treating cancer in children. Treatment for osteosarcoma or malignant fibrous histiocytoma may cause side effects. Four types of standard treatment are used: Surgery Chemotherapy Radiation therapy Samarium New types of treatment are ...

  11. Maximum Permissible Concentrations and Negligible Concentrations for Rare Earth Elements (REEs)

    NARCIS (Netherlands)

    Sneller FEC; Kalf DF; Weltje L; Wezel AP van; CSR

    2000-01-01

    In dit rapport worden maximaal toelaatbare risiconiveaus (MTR) en verwaarloosbare risiconiveaus (VR) afgeleid voor zeldzame aardmetalen (ZAM). De geselecteerde ZAMs zijn Yttrium (Y), Lanthanum (La), Cerium (Ce), Praseodymium (Pr), Neodymium (Nd), Samarium (Sm), Gadolinium (Gd), en Dysprosium

  12. Bulletin of the Chemical Society of Ethiopia - Vol 31, No 3 (2017)

    African Journals Online (AJOL)

    A novel samarium complex with interesting photoluminescence and semiconductive properties · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. D. W. Zhang, W. T. Chen, Y. F.Wang, 435-444 ...

  13. Alloying-Element Loss during High-Temperature Processing of a Nickel-Base Superalloy (Preprint)

    Science.gov (United States)

    2013-01-01

    precipitates, and the fine white/gray particles are carbides and borides . ............................................. 23 Figure 2. Aluminum...diameter billet with a measured composition in weight percent of 20.4 cobalt, 12.3 chromium, 3.5 aluminum, 3.5 titanium, 2.7 molybdenum , 4.3 tungsten...comparable size, and submicron carbides and borides . A fifteen-minute heat treatment at the subsolvus temperature used in the present work (i.e

  14. Project Squid. A Program of Fundamental Research on Liquid Rocket and Pulse Jet Propulsion for the Bureau of Aeronautics and the Office of Naval Research of the Navy Department

    Science.gov (United States)

    1948-01-01

    nitrides, and borides bonded with a refractory metal is designed to indicate quickly which areas of this interesting field are most likely to yield...investigations of the more promising systems. 51 Library research furnished only data on the properties of the individual carbides, nitrides, borides ...tungsten carbide and chromium or molybdenum plloys exhibited a Widmanstatten structure, indicating reaction between the binder and the carbide

  15. Mechanisms of Recovering Low Cycle Fatigue Damage in Incoloy 901.

    Science.gov (United States)

    1979-01-01

    borides , porosity, brittle second phases, ctc.). Kim and Laird point out that in pure metals, crack initiation occurs at persistent slip bands at low...carbo-nitrides, and borides intentionally added to control the grain size, improve creep resistance, increase grain boundary strength, and to vitiate...which can be forged and machined fairly conventionally (19). Incoloy 901 has an austenitic (y-f.c.c.) iron-nickel-chromium matrix. Molybdenum

  16. Catalysis by Single Atoms: Water Gas Shift and Ethylene Hydrogenation

    Science.gov (United States)

    2009-04-20

    2007). DOI: 10.1021/jp0744811 16 Oxidative dehydrogenation of methanol to formaldehyde by isolated vanadium, molybdenum , and chromium oxide clusters...composite Some ZrB2-metal composites can form new boride phases during laser processing, especially when binder materials possess similar chemical...properties to Zr. We have observed the formation of new boride phases when Ti and Ta binder materials are used. Figure 8 shows TiB fibers spread

  17. Development Of Electro-Spark Alloying (ESA) And Thermo-Reactive Electro-Spark Surface Strengthening (TRESS) Technologies And Set Of Equipment With Attachments For Mechanization

    Science.gov (United States)

    2006-05-11

    wear-, corrosion- and oxidation resistant coatings (up to 300 µm thick) based on oxides, carbides, silicates, borides and nitrides of transition...based on carbides, borides , nitrides, intermetallides strengthened by nanoparticles. 15. SUBJECT TERMS EOARD, Electro Spark...seems reasonable to fill the pores of coatings with a solid lubricant, such as molybdenum disulfide MoS2. Due to high roughness of ES coatings, the

  18. Specialty Metals: DOD Dissemination of National Security Waiver Information Could Enhance Awareness and Compliance with Restrictions

    Science.gov (United States)

    2014-10-01

    Restrictions Why GAO Did This Study Specialty metals—such as titanium, certain steel alloys , and samarium- cobalt alloy magnets—are essential to DOD...highly magnetic, lightweight, corrosion resistant, or having high durability. Among these metals are samarium- cobalt alloy magnets used to make radar...the following elements: aluminum, chromium , cobalt , columbium, molybdenum, nickel, titanium, tungsten, or vanadium. Specialty metals were added

  19. Synthesis and investigation of CrB{sub 4}, MnB{sub 4} and new ternary chromium and rhenium manganese borides; Synthese und Untersuchung von CrB{sub 4}, MnB{sub 4} sowie neuen ternaeren Chrom- und Rheniummanganboriden

    Energy Technology Data Exchange (ETDEWEB)

    Knappschneider, Arno

    2014-10-13

    In the present work single crystals of the tetraborides of chromium and manganese have been grown and allowed a structure refinement of the compounds. Furthermore the physical characteristics for example hardness, electronic properties and magnetism were been determined. Also the ternary tetraboride phase of chromium and manganese was synthesized and a new ternary rhenium manganese diboride could be obtained.

  20. Development of a methodology for the separation of europium and samarium from a mixture of rare earth oxides by electroreduction/ precipitation; Desenvolvimento de uma metodologia para a separacao de samario e europio a partir de mistura de oxidos de terras raras por reducao eletroquimica/precipitacao

    Energy Technology Data Exchange (ETDEWEB)

    Chepcanoff, Vera

    2006-07-01

    The rare earths (RE) were first used in 1903, when Welsbach developed a lighter that is still used today. Nowadays, the RE are employed in many different fields, as in the production of super-alloys , as catalysts for petroleum industry, in the manufacture of non-ferrous alloys, color television tubes, x-ray screens, special glasses, ceramics, computer industries, nuclear medicine, lasers, pigments, etc., moving, in the last decade , a market of US$ 2 billions per year. Due to their similar properties, the RE elements are very difficult to separate, requiring complex processes, what make the products very expensive. Elements like Eu and Sm, which contents in the minerals are low (0.05% and 2.0%, respectively, in monazite) are extremely expensive, but their field of application justifies the research for looking for other processes, more simple and/or more effective. Trivalent state is a characteristic of all RE, but some of them presents oxidation state +2, like Ce, Eu, Sm and Yb. In the case of Eu and Sm, the focus of the present work, the divalent state is achieved by electro-reduction in the potentials -0.65 and -1.55 (SCE), respectively. This makes possible the separation of these elements from the other rare earths and from each other. Thus, making use of this characteristic, a process for the individual separation of Eu and Sm in (NH{sub 4}){sub 2}SO{sub 4} solution by electro-reduction/precipitation is proposed, where Sm is first separated from the solution as sulfate, and Eu, that remains in the solution, is precipitated after the decrease of temperature and potential applied. The process developed from a synthetic Eu and Sm solution was applied to a mixture of semi-heavy RE oxide, produced at IPEN-CNEN/SP, obtaining the separation of Sm. This product was analyzed by spectrophotometry, showing high purity. (author)

  1. Tetrakis[μ-2-(3,4-dimethoxyphenylacetato]-κ4O:O′;κ3O,O′:O;κ3O:O,O′-bis{[2-(3,4-dimethoxyphenylacetato-κ2O,O′](1,10-phenanthroline-κ2N,N′samarium(III}

    Directory of Open Access Journals (Sweden)

    Jia-Lu Liu

    2010-11-01

    Full Text Available In the centrosymmetric dinuclear title complex, [Sm2(C10H11O46(C12H8N22], the SmIII ion is nine-coordinated by seven O atoms of five 2-(3,4-dimethoxyphenylacetate (DMPA ligands and two N atoms of one bis-chelating 1,10-phenanthroline (phen ligand, forming a distorted tricapped trigonal-prismatic environment. The DMPA ligands coordinate in bis-chelate, bridging and bridging tridentate modes. An intramolecular C—H...O hydrogen bond occurs. Intermolecular C—H...O interactions are also present in the crystal.

  2. Microstructure and mechanical properties of a new type of austempered boron alloyed high silicon cast steel

    Directory of Open Access Journals (Sweden)

    Chen Xiang

    2013-05-01

    Full Text Available In the present paper, a new type of austempered boron alloyed high silicon cast steel has been developed, and its microstructures and mechanical properties at different temperatures were investigated. The experimental results indicate that the boron alloyed high silicon cast steel comprises a dendritic matrix and interdendritic eutectic borides in as-cast condition. The dendritic matrix is made up of pearlite, ferrite, and the interdendritic eutectic boride is with a chemical formula of M2B (M represents Fe, Cr, Mn or Mo which is much like that of carbide in high chromium white cast iron. Pure ausferrite structure that consists of bainitic ferrite and retained austenite can be obtained in the matrix by austempering treatment to the cast steel. No carbides precipitate in the ausferrite structure and the morphology of borides remains almost unchanged after austempering treatments. Secondary boride particles precipitate during the course of austenitizing. The hardness and tensile strength of the austempered cast steel decrease with the increase of the austempering temperature, from 250 篊 to 400 篊. The impact toughness is 4-11 J昪m-2 at room temperature and the impact fracture fractogragh indicates that the fracture is caused by the brittle fracture of the borides.

  3. AlM2B2 (M  =  Cr, Mn, Fe, Co, Ni): a group of nanolaminated materials

    Science.gov (United States)

    Kádas, K.; Iuşan, D.; Hellsvik, J.; Cedervall, J.; Berastegui, P.; Sahlberg, M.; Jansson, U.; Eriksson, O.

    2017-04-01

    Combining theory with experiments, we study the phase stability, elastic properties, electronic structure and hardness of layered ternary borides AlCr2B2, AlMn2B2, AlFe2B2, AlCo2B2, and AlNi2B2. We find that the first three borides of this series are stable phases, while AlCo2B2 and AlNi2B2 are metastable. We show that the elasticity increases in the boride series, and predict that AlCr2B2, AlMn2B2, and AlFe2B2 are more brittle, while AlCo2B2 and AlNi2B2 are more ductile. We propose that the elasticity of AlFe2B2 can be improved by alloying it with cobalt or nickel, or a combination of them. We present evidence that these ternary borides represent nanolaminated systems. Based on SEM measurements, we demonstrate that they exhibit the delamination phenomena, which leads to a reduced hardness compared to transition metal mono- and diborides. We discuss the background of delamination by analyzing chemical bonding and theoretical work of separation in these borides.

  4. Study on wear resistant cast B-containing 1Cr18Ni9Ti stainless steel

    Directory of Open Access Journals (Sweden)

    Kuang Jiacai

    2009-02-01

    Full Text Available The developed 1Cr18Ni9Ti austenitic stainless steel containing 1.63 wt.%B have been characterized by X-ray diffraction (XRD, electron probe microanalyzer (EPMA, optical microscopy (OM, scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDS and Vickers microhardness measurement. The microstructural evolution and property of high boron stainless steel after solution treatment at the temperature of 1050℃ are also investigated. The results show that the main compositions of borides are Fe, Cr and B, and with small amount of Ni, Mn and C elements. Silicon is insoluble in the borides. The hardness of borides is over 1,500 HV. It has been found that borides do not decompose during solution treatment, but part of borides dissolves into the matrix. The effect of increasing the solubility of boron element in the austenitic matrix favours the hardness enhancement by 8.54%. High boron stainless steel has excellent wear resistance in corrosive environment. Lifetime of transfer pipe made of high boron-containing stainless steel is 1.5-1.8 times longer than that of boron-free 1Cr18Ni9Ti stainless steel.

  5. Effects of Tungsten Addition on the Microstructure and Corrosion Resistance of Fe-3.5B Alloy in Liquid Zinc

    Directory of Open Access Journals (Sweden)

    Xin Liu

    2017-04-01

    Full Text Available The effects of tungsten addition on the microstructure and corrosion resistance of Fe-3.5B alloys in a liquid zinc bath at 520 °C were investigated by means of scanning electron microscopy, X-ray diffraction and electron probe micro-analysis. The microstructure evolution in different alloys is analyzed and discussed using an extrapolated Fe-B-W ternary phase diagram. Experimental results show that there are three kinds of borides, the reticular (Fe, W2B, the rod-like (Fe, W3B and flower-like FeWB. The addition of tungsten can refine the microstructure and improve the stability of the reticular borides. Besides, it is beneficial to the formation of the metastable (Fe, W3B phase. The resultant Fe-3.5B-11W (wt % alloy possesses excellent corrosion resistance to liquid zinc. When tungsten content exceeds 11 wt %, the formed flower-like FeWB phase destroys the integrity of the reticular borides and results in the deterioration of the corrosion resistance. Also, the corrosion failure resulting from the spalling of borides due to the initiation of micro-cracks in the grain boundary of borides is discussed in this paper.

  6. The Kinetics and Dry-Sliding Wear Properties of Boronized Gray Cast Iron

    Directory of Open Access Journals (Sweden)

    Dong Mu

    2013-01-01

    Full Text Available Some properties of boride formed on gray cast iron (GCI have been investigated. GCI was boronized by powder-pack method using Commercial LSB-II powders at 1123, 1173, and 1223 K for 2, 4, 6, and 8 h, respectively. Scanning electron microscopy showed that boride formed on the surface of boronized GCI had tooth-shaped morphology. The hardness of boride formed on surfaces of GCI ranged from 1619 to 1343 HV0.025, and quenched and tempered GCI ranged from 400 to 610 HV0.025. The boride formed in the coating layer confirmed by X-ray diffraction analysis was Fe2B single phase. Depending on boronizing time and temperature, the thickness of coating layers on boronized GCI ranged from 26 to 105 μm. The activation energy was 209 kJ/mol for boronized GCI. Moreover, the possibility of predicting the iso-thickness of boride layers variation was studied. Dry-sliding wear tests showed that the wear resistance of boronized sample was greater than that of quenched and tempered sample.

  7. Preparation, and Luminescence Properties of SiO2@Sm(MABA-Siphen Core-Shell Structure Nanometer Composite

    Directory of Open Access Journals (Sweden)

    Feng Li-Na

    2018-01-01

    Full Text Available A novel ternary samarium complex was prepared using HOOCC6H4N(CONH(CH23Si- (OCH2CH332 (MABA-Si as first ligand, and phen as second ligand. The corresponding SiO2@Sm(MABA-Siphen core-shell structure nanometer composite was synthesized as well, and the silica spheres was the core, and the ternary samarium complex was the shell layer. The ternary samarium complex has been characterized by element analysis, molar conductivity and IR spectra. The results show that the chemical formula of the complex is Sm(MABA-Si(phen2(ClO43·2H2O. The fluorescent spectra illustrat that the luminescence properties of the samarium complex are superior. The core-shell structure of SiO2@Sm(MABA-Siphen nanometer composite is characterized by SEM, TEM and IR spectra. The SiO2@Sm(MABA-Siphen core-shell structure composites exhibit stronger emission intensity than the ternary samarium complex. The fluorescence lifetime of the complex and core-shell structure composite is measured as well.

  8. Properties of particle phases for metal-matrix-composite design.

    Science.gov (United States)

    Baron, C; Springer, H

    2017-06-01

    Successful metallurgical design of metal-matrix-composites relies on the knowledge of the intrinsic property profiles of the metal matrix and especially the compounds employed for particles, whiskers or fibres. In this work we compiled the key properties melting point, bulk modulus, shear modulus, Young׳s modulus, density, hardness, Poisson׳s ratio and structure/space group from the widespread literature data for the most relevant compound types, i.e. borides, carbo-borides, carbides, oxides, nitrides and intermetallic phases.

  9. Field Emission Cold Cathode Devices Based on Eutectic Systems

    Science.gov (United States)

    1981-07-01

    molten aluminium. Finally it should be noted that at 800C LaB6 is in equilibrium with a variety of ternary borides of molybdenum and tungsten, e.g. (Mo...alloy containing molybdenum fibres designated A77-205. The maximum current density obtained from -2 the four systems tested were: VC 5.8, TaC 0.5...Selected physical properties of refractory carbides. TABLE 2. Selected physical properties of refractory borides . TABLE 3. Selected physical properties of

  10. Direct determination of the enthalpy of formation of MoB in synthesis from simple substances in an SHS system

    Science.gov (United States)

    Lavut, E. G.; Chelovskaya, N. V.; Kashireninov, O. E.

    1993-10-01

    In a calorimetric bomb equipped with an electric microfurnace for heating a sample, self-propagating high-temperature synthesis (SHS) of molybdenum boride is realized in accordance with the reaction Mo (c) +B (amorph.)=MoB (c); the enthalpy of this reaction is measured, and the standard enthalpy of formation of molybdenum boride from metal molybdenum and crystaline boron is calculated: Δf H 0 (MoB,c,δ,β)=103.9α1.2kJ/mole.

  11. High-Temperature Ceramic Matrix Composite with High Corrosion Resistance

    Science.gov (United States)

    2010-06-02

    individual zirconium boride and, especially, molybdenum disilicide. STCU PROJECT P286 – FINAL REPORT PAGE 16 02-Jun-10 2...Fragment of XRD pattern for molybdenum silicide. Fig. 2.5. XRD pattern for USS-22+ 2 vol.% TaB2 hot-pressed samples. Fig. 2.6. XRD pattern for USS-22...P286 – FINAL REPORT PAGE 12 02-Jun-10 1. Introduction Ceramic borides , such as hafnium diboride (HfB2) and zirconium diboride (ZrB2

  12. Collaborative Research and Development (CR&D). Delivery Order 0031: Basic Research and Development of Ti-B Alloys

    Science.gov (United States)

    2006-09-01

    ingot. The boride phase formed in situ due to boron addition was confirmed to be TiB from X-ray diffraction. Detailed microstructural examination on all...rates in the range 10-5-10-1 S-1. TZM "-f 7.0 ( molybdenum -based alloy) material was procured and Fig. 2 Sample geometry grips were fabricated to...equilibrium be­ tween solute rejection at the solidification front, the forma­ tion of borides , and alloy nucleation ahead of the front. The mechanism of

  13. Molten Boron Phase-Change Thermal Energy Storage to Augment Solar Thermal Propulsion Systems

    Science.gov (United States)

    2011-07-13

    Thermodynamic Properties of Transition Metal Borides . I. The Molybdenum -boron system and Elemental Boron," Journal of Physical Chemistry, Vol. 81... Molybdenum -Boron and Some Properties of The Molybdenum - Borides ," Journal of Metals, September 1952, pp. 983-988. 40Stout, N. D., Mar, R. W., and Boo, W. O...BeO 3010 2.43 1.458 3,410 Molybdenum 2890 0.255 0.153 391 Silicon Carbide 2818 1.47 0.882 --- B4C 2673 2.51 1.506 1,900 Boron 2570 2.93 4,650

  14. Electrically conductive containment vessel for molten aluminum

    Science.gov (United States)

    Holcombe, C.E.; Scott, D.G.

    1984-06-25

    The present invention is directed to a containment vessel which is particularly useful in melting aluminum. The vessel of the present invention is a multilayered vessel characterized by being electrically conductive, essentially nonwettable by and nonreactive with molten aluminum. The vessel is formed by coating a tantalum substrate of a suitable configuration with a mixture of yttria and particulate metal 10 borides. The yttria in the coating inhibits the wetting of the coating while the boride particulate material provides the electrical conductivity through the vessel. The vessel of the present invention is particularly suitable for use in melting aluminum by ion bombardment.

  15. Phase equilibrium in system Ti-Si-C-B and synthesis of MAX phase layers in vacuum under the influence of electron beam

    Science.gov (United States)

    Smirnyagina, N. N.; Khaltanova, V. M.; Dasheev, D. E.; Lapina, A. E.

    2017-05-01

    Composite layers on the basis of carbides and borides the titan and silicon on titanic alloy VТ-1 are generated at diffused saturation by electron beam treatment in vacuum. Formation in a composite of MAX phase Ti3SiC2 is shown. Thermodynamic research of phase equilibrium in systems Ti-Si-C and Ti-B-C in the conditions of high vacuum is executed. The thermodynamics, formation mechanisms of superfirm layers borides and carbides of the titan and silicon are investigated.

  16. New Process for Grain Refinement of Aluminum. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Joseph A. Megy

    2000-09-22

    A new method of grain refining aluminum involving in-situ formation of boride nuclei in molten aluminum just prior to casting has been developed in the subject DOE program over the last thirty months by a team consisting of JDC, Inc., Alcoa Technical Center, GRAS, Inc., Touchstone Labs, and GKS Engineering Services. The Manufacturing process to make boron trichloride for grain refining is much simpler than preparing conventional grain refiners, with attendant environmental, capital, and energy savings. The manufacture of boride grain refining nuclei using the fy-Gem process avoids clusters, salt and oxide inclusions that cause quality problems in aluminum today.

  17. Udvikling af materialer til brintpermeable membraner

    DEFF Research Database (Denmark)

    Bentzer, Henrik Karnøe

    Due to global warming as well as other factors, it is necessary to find alternatives to the current consumption of fossil fuels. Oxide materials with high protonic conductivity can potentially find application within many different technological fields in a society that is based on renewable energy...... doped samarium titanate, lanthanum magnesium titanate and strontium cerate doped with yttrium and nickel. Concentration cell measurements were used to estimate transport numbers for protons and oxide ions in yttrium doped strontium cerate and calcium doped samarium titanate. Furthermore, the voltage...

  18. {6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne]diphenolato-1κ4O1,O1′,O6,O6′:2κ4O1,N,N′,O1′}(ethanol-1κO-μ-nitrato-1:2κ2O:O′-dinitrato-1κ4O,O′-samarium(IIIzinc(II

    Directory of Open Access Journals (Sweden)

    Qiang Huang

    2009-10-01

    Full Text Available In the title heteronuclear ZnII–SmIII complex, [SmZn(C18H18N2O4(NO33(CH3CH2OH], with the hexadentate Schiff base compartmental ligand N,N′-bis(3-methoxysalicylideneethylenediamine (H2L, the SmIII and ZnII ions are triply bridged by two phenolate O atoms from the Schiff base ligand and one nitrate anion. The five-coordinate ZnII ion is in a square-pyramidal geometry formed by the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The SmIII center is in a ten-fold coordination of O atoms, involving the phenolate O atoms, two methoxy O atoms, one ethanol O atom, and two O atoms from two nitrate anions and one from the bridging nitrate anion. In the crystal, intermolecular O—H...O and C—H...O interactions generate a layer structure extending parallel to (101.

  19. Joint electroreduction of lanthanum, gadolinium and boron in halide melts

    Directory of Open Access Journals (Sweden)

    Khushkhov KH.B.

    2003-01-01

    Full Text Available The joint electroreduction of La, Gd and B from chloride-fluoride melts has been studied by cyclic voltametry. Based on the analysis of voltamograms the possibility of electrosynthesis of lanthanum-gadolinium borides from chloride-fluoride melts has been shown.

  20. Effect of spin polarization on the structural properties and bond ...

    Indian Academy of Sciences (India)

    Abstract. In this paper, spin and non-spin polarization (SP, NSP) are performed to study structural properties and bond hardness of FexB (x = 1, 2, ... ture toughness of iron boride layer depend on process time and temperature [5,6]. .... Mechanical and thermodynamic properties were calculated for the ferromagnetic (FM) and ...

  1. Flydende fase sintring af rustfrit stål

    DEFF Research Database (Denmark)

    Maahn, Ernst Emanuel; Mathiesen, Troels

    1998-01-01

    on addition of boride to AISI 316L type steels has previously proved to be sensitive to intergranular corrosion due to formation of intermetallic phases. In order to improve this system further, application of other alloy systems based on a higher alloyed 904L type stainless steel powder (PM 150) has been...

  2. Photovoltaic cell

    Science.gov (United States)

    Gordon, Roy G.; Kurtz, Sarah

    1984-11-27

    In a photovoltaic cell structure containing a visibly transparent, electrically conductive first layer of metal oxide, and a light-absorbing semiconductive photovoltaic second layer, the improvement comprising a thin layer of transition metal nitride, carbide or boride interposed between said first and second layers.

  3. Effect of Relative Humidity on the Tribological Properties of Self-Lubricating H3BO3 Films Formed on the Surface of Steel Suitable for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    E. Hernández-Sanchez

    2015-01-01

    Full Text Available The effect of environmental humidity on the self-lubricating properties of a thin film of boric acid (H3BO3 was evaluated. H3BO4 films were successfully formed on the surface of AISI 316L steel. The study was conducted on AISI 316L steel because of its use in biomedical applications. First, the samples were exposed to boriding to generate a continuous surface layer of iron borides. The samples were then exposed to a short annealing process (SAP at 1023 K for 5 min and cooled to room temperature while controlling the relative humidity (RH. Five different RH conditions were tested. The purpose of SAP was to promote the formation of a surface film of boric acid from the boron atoms present in the iron boride layers. The presence of the boric acid at the surface of the borided layer was confirmed by Raman spectroscopy and X-ray diffraction (XRD. The self-lubricating capability of the films was demonstrated using the pin-on-disk technique. The influence of RH was reflected by the friction coefficient (FC, as the samples cooled with 20% of RH exhibited FC values of 0.16, whereas the samples cooled at 60% RH showed FC values of 0.02.

  4. Microwave synthesis of electrode materials for lithium batteries

    Indian Academy of Sciences (India)

    Unknown

    Bi4B2O9 have been used as cathodes (Jones and Akridge. 1995). ... reactive, is a superb secondary heater (Vaidhyanathan et al 1997). Researches at our laboratory and elsewhere have demonstrated the use of microwaves in the synthesis of a wide ... 1997a), silicides (Vaidhyanathan and Rao 1997b), borides. (Mingos ...

  5. The adhesion of hot-filament CVD diamond films on AISI type 316 austenitic stainless steel

    NARCIS (Netherlands)

    Buijnsters, J.G.; Shankar, P.; Enckevort, W.J.P. van; Schermer, J.J.; Meulen, J.J. ter

    2004-01-01

    Steel ball indentation and scratch adhesion testing of hot filament chemical vapour deposited diamond films onto AISI type 316 austenitic stainless steel substrates using two different interlayer systems, namely chromium nitride and borided steel, have been investigated. In order to compare the

  6. Electrospark Deposition for Depot- and Field-Level Component Repair and Replacement of Hard Chromium Plating

    Science.gov (United States)

    2008-02-01

    surfaces. Commonly used electrodes for wear and friction enhancement include sintered carbides, borides , and hard alloys such as Stellite 1, Stellite 6...Tribaloy 700 and 800, and molybdenum . The dynamic coefficient of friction of machine component surfaces can be reduced from 0.6 to less than 0.2

  7. Time-resolved Langmuir Probing of a New Lanthanum Hexaboride (LaB6) Hollow Cathode

    Science.gov (United States)

    2011-09-01

    unlike refractory metals such as tungsten and molybdenum , it is not susceptible to boron diffusion from the LaB6 insert or the boron nitride heater...2 Lafferty, J. M., “ Boride Cathodes,” Journal of Applied Physics, vol. 22, no. 3, 1951, pp. 299-309. 3 Kim, V., Popov, G., Arkhipov, B., Murashko

  8. iMAST FY2007 Annual Report

    Science.gov (United States)

    2007-01-01

    multilayer design. Completed Programs Three Molybdenum (Mo) and three Nickel (Ni) coated blades along with six copper- nickel-indium (CuNiIn) coated...gas flow metering (nitrogen, argon, acetylene, and hydrogen) for depositing metallic, nitride, boride , and carbide materials in

  9. Manufacturing Methods & Technology Project Execution Report. Second Half CY 1980

    Science.gov (United States)

    1981-03-01

    MATERIAL. 1 81 7302 PRODUCTION OF BORIDE COATED LONG LIFE TOOLS AIRFRAME COMPONENTS AND PRINTED CIRCUIT BOARDS OF FIBERGLASS AND OTHER COMPOSITES ARE...SPERRY DEVELOPED A METHOD TO VAPOR DEPOSIT MOLYBDENUM CONES + A GATE FILM IN * ON A SILICON DIOXIDE LAYER TO FORM THOUSANDS OF TINY EMITTERS. SPERRY’S

  10. DEVELOPMENT OF A HIGH TEMPERATURE LIQUID METAL SOLUTION CALORIMETER.

    Science.gov (United States)

    alloys and many inorganic compounds, including such materials as steels, refractory metal alloys, carbides, borides , and silicides. Because of the high...alumina is used for other parts. Heat is supplied through molybdenum wire resistance windings and controlled by a proportioning controller. Temperatures

  11. Characterization of natural zeolite clinoptilolite for sorption of contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Xingu-Contreras, E., E-mail: nyleve-18@hotmail.com; García-Rosales, G., E-mail: gegaromx@yahoo.com.mx [Instituto Tecnológico de Toluca (Mexico); García-Sosa, I., E-mail: irma.garcia@inin.gob.mx; Cabral-Prieto, A., E-mail: agustin.cabral@inin.gob.mx; Solache-Ríos, M., E-mail: marcos.solache@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares, Departamento de Química (Mexico)

    2015-06-15

    The nanoparticles technology has received considerable attention for its potential applications in groundwater treatment for the removal of various pollutants as Cadmium. In this work, iron boride nanoparticles were synthesized in pure form and in presence of homo-ionized zeolite clinoptilolite, as support material. These materials were used for removing Cd (II) from aqueous solutions containing 10, 50, 100, 150, 200, 250, 300 and 400 mg/L. The characterization of these materials was made by using X-ray Diffraction, Scanning Electron Microscopy and Mössbauer Spectroscopy. Pure iron boride particles show a broad X-ray diffraction peak centered at 45{sup ∘} (2θ), inferring the presence of nanocrystals of Fe{sub 2}B as identified from Mössbauer Spectroscopy. The size of these Fe{sub 2}B particles was within the range of 50 and 120 nm. The maximum sorption capacities for Cd (II) of iron boride particles and supported iron boride particles in homo-ionized zeolitic material were nearly 100 %. For homo-ionized zeolite and homo-ionized zeolite plus sodium borohydride was ≥ 95 %.

  12. Laser alloying of bearing steel with boron and self-lubricating addition

    Directory of Open Access Journals (Sweden)

    Kotkowiak Mateusz

    2016-12-01

    Full Text Available 100CrMnSi6-4 bearing steel has been widely used for many applications, e.g. rolling bearings which work in difficult operating conditions. Therefore, this steel has to be characterized by special properties such as high wear resistance and high hardness. In this study laser-boriding was applied to improve these properties. Laser alloying was conducted as the two step process with two different types of alloying material: amorphous boron only and amorphous boron with addition of calcium fluoride CaF2. At first, the surface was coated with paste including alloying material. Second step of the process consisted in laser re-melting. The surface of sample, coated with the paste, was irradiated by the laser beam. In this study, TRUMPF TLF 2600 Turbo CO2 laser was used. The microstructure, microhardness and wear resistance of both laser-borided layer and laser-borided layer with the addition of calcium fluoride were investigated. The layer, alloyed with boron and CaF2, was characterized by higher wear resistance than the layer after laser boriding only.

  13. Effect of preparation temperature and ions doping on size ...

    African Journals Online (AJOL)

    Binary and quaternary amorphous nano powders are prepared by wet reduction method. Cobalt boride nano catalyst is synthesized at 10 and 60 ºC. Effect of preparation temperature on size and morphology was studied. Co-M-Zr-B (M: Cr, Mo and W) as quaternary catalysts are also prepared in order to studying ions ...

  14. Doped Boron Carbide-Based Polymers: Fundamental Studies of a Novel Class of Materials for Enhanced Neutron Detection

    Science.gov (United States)

    2016-03-01

    Society 58 (2013) 147; Abstract: B16.00014; Session B16: Focus Session: Spin-Dependent Physics in Graphene , Room: 318; 1:51 PM–2:03 PM [presented by...Boron Carbide Semiconductors : So Many Devices and Applications, So Little Understanding”, 118th International Symposium on Boron, Borides and Related

  15. Molecular indicators for palaeoenvironmental change in a Messinian evaporitic sequence (Vena del Gesso, Italy) II. Stratigraphic changes in abundances and (13)C contents of free and sulphur-bound skeletons in a single marl bed

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Kenig, F.; Frewin, N.L.; Hayes, J.M.

    1995-01-01

    The extractable organic matter of 10 immature samples from a marl bed of one evaporitic cycle of the Vena del Gesso sediments (Gessoso-solfifera Fm., Messinian, Italy) was analyzed quantitatively for free hydrocarbons and organic sulphur compounds. Nickel boride was used as a desulphurizing agent to

  16. Electrochemical Corrosion Behavior of Spray-Formed Boron-Modified Supermartensitic Stainless Steel

    Science.gov (United States)

    Zepon, Guilherme; Nogueira, Ricardo P.; Kiminami, Claudio S.; Botta, Walter J.; Bolfarini, Claudemiro

    2017-04-01

    Spray-formed boron-modified supermartensitic stainless steel (SMSS) grades are alloys developed to withstand severe wear conditions. The addition of boron to the conventional chemical composition of SMSS, combined with the solidification features promoted by the spray forming process, leads to a microstructure composed of low carbon martensitic matrix reinforced by an eutectic network of M2B-type borides, which considerably increases the wear resistance of the stainless steel. Although the presence of borides in the microstructure has a very beneficial effect on the wear properties of the alloy, their effect on the corrosion resistance of the stainless steel was not comprehensively evaluated. The present work presents a study of the effect of boron addition on the corrosion resistance of the spray-formed boron-modified SMSS grades by means of electrochemical techniques. The borides fraction seems to have some influence on the repassivation kinetics of the spray-formed boron-modified SMSS. It was shown that the Cr content of the martensitic matrix is the microstructural feature deciding the corrosion resistance of this sort of alloys. Therefore, if the Cr content in the alloy is increased to around 14 wt pct to compensate for the boron consumed by the borides formation, the corrosion resistance of the alloy is kept at the same level of the alloy without boron addition.

  17. Adhesive and Cohesive Strength in FeB/Fe2B Systems

    Science.gov (United States)

    Meneses-Amador, A.; Blancas-Pérez, D.; Corpus-Mejía, R.; Rodríguez-Castro, G. A.; Martínez-Trinidad, J.; Jiménez-Tinoco, L. F.

    2018-01-01

    In this work, FeB/Fe2B systems were evaluated by the scratch test. The powder-pack boriding process was performed on the surface of AISI M2 steel. The mechanical parameters, such as yield stress and Young's modulus of the boride layer, were obtained by the instrumented indentation technique. Residual stresses produced on the boride layer were estimated by using the x-ray diffraction (XRD) technique. The scratch test was performed in order to evaluate the cohesive/adhesive strength of the FeB/Fe2B coating. In addition, a numerical evaluation of the scratch test on boride layers was performed by the finite element method. Maximum principal stresses were related to the failure mechanisms observed by the experimental scratch test. Shear stresses at the interfaces of the FeB/Fe2B/substrate system were also evaluated. Finally, the results obtained provide essential information about the effect of the layer thickness, the residual stresses, and the resilience modulus on the cohesive/adhesive strength in FeB/Fe2B systems.

  18. Role of boron addition on the consolidation and properties of steel ...

    Indian Academy of Sciences (India)

    The examinations have revealed the presence of numerous fine complex borides in the microstructure of the steel–8% TiB2 and steel–8% TiB2–1% B composites. Author Affiliations. Iwona Sulima1. Institute of Technology, Pedagogical University of Krakow, Podchorazych 2 St., 30-084 Krakow, Poland. Dates. Manuscript ...

  19. Pitting corrosion behaviour of diamond coated tool steel

    NARCIS (Netherlands)

    Buijnsters, J.G.; Subba Rao, R.V.; Shankar, P.; Enckevort, W.J.P. van; Schermer, J.J.; Gebert, A.; Meulen, J.J. ter

    2005-01-01

    Using a hot filament chemical vapour deposition reactor, diamond films of approximately 2-3 mum in thickness were deposited on tool steel specimens with three different interlayer systems, namely CrN, Si and borided steel. The morphology, defect densities and residual stresses of the diamond films

  20. Synthesis of carbon fibre-reinforced, silicon carbide composites by ...

    Indian Academy of Sciences (India)

    pyrolysis (PIP), liquid silicon infiltration (LSI), sol–gel, reaction hot-pressing, have been used for ... resin matrix and is then infiltrated with molten silicon (Krenkel 2001); but the presence of free silicon may act as a ... and (iv) finally carbothermal reduction of oxides to carbides/borides at 1873 and 1973 K for 3 h as shown by ...

  1. Quantitative assessment of mono- and polysulphide-linked carbon skeletons of S-rich macromolecular aggregates present in bitumens and oils

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Schouten, S.; Baas, M.; Kock-van Dalen, A.C.; Kohnen, M.E.L.; Leeuw, J.W. de

    1995-01-01

    Polar fractions of three immature sulphur-rich sediments and four sulphur-rich oils, all of Miocene age, were studied using two selective chemolytic methods, namely methyl lithium/methyl iodide, which selectively cleaves polysulphide bonds, and Raney nickel or nickel boride which cleave both

  2. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. Ibrahim Gunes. Articles written in Sadhana. Volume 38 Issue 3 June 2013 pp 513-526. Investigation of diffusion kinetics of plasma paste borided AISI 8620 steel using a mixture of B2O3 paste and B4C/SiC · Ibrahim Gunes Sukru Taktak Cuma Bindal Yilmaz Yalcin Sukru Ulker Yusuf Kayali.

  3. Performance Characterization of a Novel Plasma Thruster to Provide a Revolutionary Operationally Responsive Space Capability with Micro- and Nano-Satellites

    Science.gov (United States)

    2011-03-24

    Einstein Spontaneous Emission Rate Coefficient Electrical Utilization Efficiency Electron Electron Density...0.135 Tesla samarium cobalt (SmCo) permanent magnet from Electron Energy Corp. in Landisville, PA. Encapsulating the assembly is a simple aluminum...unlike some well-developed technologies, such as solid fueled rocket motors , an electric propulsion system could simultaneously contribute to all three

  4. Xe-135 and Sm-149 Isotopic Evolution Analysis Xesamo code; Analisis de la Evolucion Isotopica del Xe-135 y Sm-149. Programa Xesamo

    Energy Technology Data Exchange (ETDEWEB)

    Caro, R.; Gallego, J.; Martinez Fanegas, R.

    1977-07-01

    In this report the time evolution analysis of the nuclides concentration Xe-135 and Sm-149 as a function of the neutron flux is carried out. The neutron flux may be any function of time. It is analyzed as well the reactivity changes associated with the xenon and samarium concentration variations. (Author) 5 refs.

  5. Thermoluminescence characteristics of Sm doped NaYF4 crystals

    Indian Academy of Sciences (India)

    2006-06-28

    Jun 28, 2006 ... temperature peaks also vary in relation to the Sm3+ con- centration in NaYF4. This indicates a probable change in the trap structure of NaYF4 with the doping concentration of samarium impurity. This observation is in conformity with the earlier studies (Narasimha Reddy et al 1987;. Gopal Reddy et al 1988; ...

  6. Multiplet effects in the electronic structure of light rare-earth metals

    NARCIS (Netherlands)

    Lebegue, S.; Svane, A.; Katsnelson, M.I.; Lichtenstein, A.I.; Eriksson, O.

    2006-01-01

    The excited-state properties of the light rare-earth elemental metals praseodymium, neodymium, and samarium are studied within the Hubbard-I formalism. This method describes the multiplets of the rare-earth f shell by an exact diagonalization of the two-body part of the Hamiltonian. Subsequently,

  7. Structural, dielectric and electrical properties of Sm-modified Pb ...

    Indian Academy of Sciences (India)

    It is observed that. the dielectric permittivity () and loss tangent (tan ) are dependent on frequency,; the temperature of dielectric permittivity maximum shifts toward lower temperature side with the increase of samarium ion (Sm+3) concentration at the Pb sites, and; observed and calculated -values of XRD patterns show ...

  8. Ironless-armature brushless motor

    Science.gov (United States)

    Fisher, R. L.

    1977-01-01

    Device uses 12-pole samarium cobalt permanent-magnet rotor and three Hall-effect sensors for commutation. In prototype motor, torque constant (3-phase delta) is 65 oz-in/amp; electrical time constant (L/R) is 0.2 x 0.001 sec, and armature resistance is 20 ohms.

  9. Measurement of total angular momentum values of high-lying even ...

    Indian Academy of Sciences (India)

    Measurement of total angular momentum values of high-lying even-parity atomic states of samarium by spectrally resolved laser-induced fluorescence technique. A K PULHANI∗, M L SHAH, G P GUPTA and B M SURI. Laser and Plasma Technology Division, Bhabha Atomic Research Centre,. Mumbai 400 085, India.

  10. Measurement of total angular momentum values of high-lying even ...

    Indian Academy of Sciences (India)

    Spectrally resolved laser-induced fluorescence technique was used to uniquely assign total angular momentum () values to high-lying even-parity energy levels of atomic samarium. Unique value assignment was done for seven energy levels in the energy region 34,800–36,200 cm-1 , recently observed and reported in ...

  11. X-Ray studies reveal lanthanide binding sites at the A/B5 interface of E. coli heat labile enterotoxin

    NARCIS (Netherlands)

    Sixma, Titia K.; Terwisscha van Scheltinga, Anke C.; Kalk, Kor H.; Zhou, Kangjing; Wartna, Ellen S.; Hol, Wim G.J.

    1992-01-01

    The crystal structure determination of heat labile enterotoxin (LT) bound to two different lanthanide ions, erbium and samarium, revealed two distinct ion binding sites in the interface of the A subunit and the B pentamer of the toxin. One of the interface sites is conserved in the very similar

  12. X-RAY STUDIES REVEAL LANTHANIDE BINDING-SITES AT THE A/B5 INTERFACE OF ESCHERICHIA-COLI HEAT LABILE ENTEROTOXIN

    NARCIS (Netherlands)

    SIXMA, TK; VANSCHELTINGA, ACT; KALK, KH; WARTNA, ES; HOL, WGJ

    1992-01-01

    The crystal structure determination of heat labile enterotoxin (LT) bound to two different lanthanide ions, erbium and samarium, revealed two distinct ion binding sites in the interface of the A subunit and the B pentamer of the toxin. One of the interface sites is conserved in the very similar

  13. Author Details

    African Journals Online (AJOL)

    Prasad, T.N.V.K.. Vol 12, No 2 (2003) - Articles Pyroelectric Ferroelectric and Resistivity Studies on Samarium Modified Barium Strontium Sodium Niobate Ceramics Abstract. ISSN: 1019-1593. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  14. Thermoluminescent coactivated rare earth oxyhalide phosphors and X-ray image converters utilizing said phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Rabatin, J.G.

    1984-11-06

    Oxyhalides of lanthanum, gadolinium and lutetium coactivated with a first activator selected from bismuth and samarium to provide the color of light emission and a second coactivator which increases the amount of stored energy in a stored radiographic latent image are found to be superior in their conversion efficiency of x-rays to visible light.

  15. Interactions between exogenous rare earth elements and phosphorus leaching in packed soil columns

    Science.gov (United States)

    Rare earth elements (REEs) increasingly used in agriculture as an amendment for crop growth may help to lessen environmental losses of phosphorus (P) from heavily fertilized soils. The vertical transport characteristics of P and REEs, lanthanum (La), neodymium (Nd), samarium (Sm), and cerium (Ce), w...

  16. Simplified syntheses of the water-soluble chiral shift reagents Sm-(R)-pdta and Sm-(S)-pdta

    Czech Academy of Sciences Publication Activity Database

    Hrubá, L.; Buděšínský, Miloš; Pícha, Jan; Jiráček, Jiří; Vaněk, Václav

    2013-01-01

    Roč. 54, č. 47 (2013), s. 6296-6297 ISSN 0040-4039 Institutional support: RVO:61388963 Keywords : NMR * chiral shift reagents * Sm-pdta * PDTA * samarium * 1,2-diaminopropane Subject RIV: CC - Organic Chemistry Impact factor: 2.391, year: 2013

  17. Perovskite catalysts for oxidative coupling

    Science.gov (United States)

    Campbell, Kenneth D.

    1991-01-01

    Perovskites of the structure A.sub.2 B.sub.2 C.sub.3 O.sub.10 are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  18. Lanthanide(III) complexes with tridentate Schiff base ligand ...

    African Journals Online (AJOL)

    The tridentate N4-type Schiff base was synthesized from the condensation reaction of 2-hydrazinopyridine and pyridine-2-carbaldehyde. Neodymium and Samarium complexes were isolated when the corresponding nitrate salt was added to the solution of the ligand. The isolated compounds were characterized by ...

  19. Author Details

    African Journals Online (AJOL)

    T. Chen, W. Vol 31, No 3 (2017) - Articles A novel samarium complex with interesting photoluminescence and semiconductive properties. Abstract PDF. ISSN: 1726-801X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms ...

  20. The effect of rare-earth filtration on organ doses in intraoral radiography

    Energy Technology Data Exchange (ETDEWEB)

    Asako, Satoshi; Satoh, Kenji; Furumoto, Keiichi (Nippon Dental Univ., Tokyo (Japan))

    1994-08-01

    Filters of rare-earth elements such as lanthanum (La, Z=57), samarium (Sm, Z=62), gadolinium (Gd, Z=64) and erbium (Er, Z=68) are frequently used in radiography for the purpose of reducing the patient dose by eliminating low-energy and high-energy X-rays which are not involved in imaging. It is useful to evaluate the dose reduction achieved by these rare-earth filters in terms of organ dose, and the effective dose equivalent, which is used for evaluating carcinogenic risks and hereditary effects of X-ray irradiation, for the purpose of optimizing the radiographic technique and radiation protection. Therefore, we calculated the organ dose and effective dose equivalent during intraoral radiography of the maxillary incisor region by simulation using samarium or erbium, typical rare-earth elements, in filtration. We evaluated the effects of these metals in dose reduction. When samarium or erbium, 0.1 mm thick, was used in added filtration at tube voltage of 60, 70, 80 and 90 kV, the time required for radiography almost doubled, respectively. The organ dose at each tube voltage was the largest in the parathyroid and thyroid glands, followed by bone surfaces and the optic lenses, skin, red bone marrow and salivary glands, larynx, and brain, in that order. The organ dose at sites other than the larynx and brain decreased as the quality of the incident X-ray beam was hardened. When samarium or erbium was added at each voltage, the effective dose equivalent was reduced by about 20% to 45%. Erbium was more effective than samarium in reducing the effective dose equivalent, and either of the two elements decreased its effectiveness with an increase in tube voltage. (author) 43 refs.

  1. Phase identification in boron-containing powder metallurgy steel using EBSD in combination with EPMA

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Ming-Wei, E-mail: mwwu@ntut.edu.tw; Cai, Wen-Zhang

    2016-03-15

    Boron (B) is extensively used to induce liquid phase sintering (LPS) in powder metallurgy (PM) steels and thereby increase the densification. The alloying elements in B-containing PM steels affect the boride phase, stability of the boride, the temperature of liquid formation, and the progress of LPS. However, the boride phase has not been systematically identified yet. The main objective of this study was to clarify the influences of alloying elements, including C, Cr, and Ni, on the boride phases using electron backscatter diffraction (EBSD) in combination with electron probe microanalysis (EPMA). Network structures consisting of ferrite, Fe{sub 2}B boride, and Fe{sub 3}C carbide were extensively observed in the Fe–0.4B–0.5C steel. The portions of Fe{sub 2}B were sufficiently larger than those of Fe{sub 3}C, and Fe{sub 3}C was mostly distributed at the interfaces between ferrite and Fe{sub 2}B. Adding 1.5 wt.% Cr or 1.8 wt.% Ni to Fe–0.4B–0.5C steel completely changes the Fe{sub 2}B and Fe{sub 3}C phases to a M{sub 3}(B,C) phase, where M represents the metallic elements, including Fe, Cr, Mo, and Ni. Furthermore, Cr, Mo, B, and C atoms tend to concentrate on the M{sub 3}(B,C) phase, but Ni atoms do not. - Highlights: • Network structures consisting of ferrite, Fe{sub 2}B boride, and Fe{sub 3}C carbide were extensively observed in the Fe–0.4B–0.5C steel. • Adding 1.5 wt.% Cr or 1.8 wt.% Ni to Fe–0.4B–0.5C steel completely transforms the Fe{sub 2}B and Fe{sub 3}C phases to a M{sub 3}(B,C) phase. • Cr, Mo, B, and C atoms tend to concentrate on the M{sub 3}(B,C) phase, but Ni atoms do not.

  2. Ternary ceramic thermal spraying powder and method of manufacturing thermal sprayed coating using said powder

    Energy Technology Data Exchange (ETDEWEB)

    Vogli, Evelina; Sherman, Andrew J.; Glasgow, Curtis P.

    2018-02-06

    The invention describes a method for producing ternary and binary ceramic powders and their thermal spraying capable of manufacturing thermal sprayed coatings with superior properties. Powder contain at least 30% by weight ternary ceramic, at least 20% by weight binary molybdenum borides, at least one of the binary borides of Cr, Fe, Ni, W and Co and a maximum of 10% by weight of nano and submicro-sized boron nitride. The primary crystal phase of the manufactured thermal sprayed coatings from these powders is a ternary ceramic, while the secondary phases are binary ceramics. The coatings have extremely high resistance against corrosion of molten metal, extremely thermal shock resistance and superior tribological properties at low and at high temperatures.

  3. Microstructure, microhardness, phase analysis and chemical composition of laser remelted FeB-Fe2B surface layers produced on Vanadis-6 steel

    Science.gov (United States)

    Bartkowska, Aneta; Swadźba, Radosław; Popławski, Mikołaj; Bartkowski, Dariusz

    2016-12-01

    The paper presents the study results of the diffusion boronized layer and their laser modification. Diffusion boronized processes were carried out on Vanadis-6 steel at 900 °C for 5 h. Boronized layers were characterized by dual-phase microstructure consisting of iron borides having a microhardness in the range from 1800 to 1400 HV. The laser heat treatment was carried out using CO2 laser after diffusion boronizing process. The research goals of this paper was analysis of microstructure, microhardness as well as phase and chemical composition of boronized layers after laser modification. Microstructure of boronized layer after laser modification consisted of remelted zone, heat affected zone and substrate. Remelted zone was characterized by microstructure consisted of boron-martensite eutectic. In this zone, the phases of borides and carbides were detected. Boronized layers after laser modification were characterized by the mild gradient of microhardness from surface to the substrate.

  4. Ceramic fibers from Si-B-C polymer precursors

    Science.gov (United States)

    Riccitiello, S. R.; Hsu, M. S.; Chen, T. S.

    1993-01-01

    Non-oxide ceramics such as silicon carbide (SiC), silicon nitride (Si3N4), and silicon borides (SiB4, SiB6) have thermal stability, oxidation resistance, hardness, and varied electrical properties. All these materials can be prepared in a fiber form from a suitable polymer precursor. The above mentioned fibers, when tested over a temperature range from 25 to 1400 C, experience degradation at elevated temperatures. Past work in ceramic materials has shown that the strength of ceramics containing both carbides and borides is sustained at elevated temperatures, with minimum oxidation. The work presented here describes the formation of ceramic fibers containing both elements, boron and silicon, prepared via the polymer precursor route previously reported by the authors, and discusses the fiber mechanical properties that are retained over the temperature range studied.

  5. RESEARCH OF PROCESS OF AN ALLOYING OF THE FUSED COATINGS RECEIVED FROM THE SUPERFICIAL ALLOYED WIRE BY BORON WITH IN ADDITIONALLY APPLIED ELECTROPLATED COATING OF CHROME AND COPPER

    Directory of Open Access Journals (Sweden)

    V. A. Stefanovich

    2015-01-01

    Full Text Available Researches on distribution of chrome and copper in the fused coating received from the superficial alloyed wire by boron with in additionally applied electroplated coating of chrome and copper were executed. The structure of the fused coating consists of dendrites on which borders the boride eutectic is located. It is established that the content of chrome in dendrites is 1,5– 1,6 times less than in the borid; distribution of copper on structure is uniformed. Coefficients of digestion of chrome and copper at an argon-arc welding from a wire electrode with electroplated coating are established. The assimilation coefficient for chrome is equal to 0,9–1,0; for copper – 0,6–0,75.

  6. Perspectives of High-Temperature Thermoelectric Applications and p-type and n-type Aluminoborides

    Science.gov (United States)

    Mori, T.

    2016-10-01

    A need exists to develop high-temperature thermoelectric materials which can utilize high-temperature unutilized/waste heat in thermal power plants, steelworks, factories, incinerators, etc., and also focused solar power. The thermal power plant topping application is of potential high impact since it can sizably increase the efficiency of power plants which are the major supply of electrical power for many countries. Higher borides are possible candidates for their particular high-temperature stability, generally large Seebeck coefficients, α, and intrinsic low thermal conductivity. Excellent (|α| > 200 μV/K) p-type or n-type behavior was recently achieved in the aluminoboride YAl x B14 by varying the occupancy of Al sites, x. Finding p-type and n-type counterparts has long been a difficulty of thermoelectric research not limited to borides. This paper reviews possible high-temperature thermoelectric applications, and recent developments and perspectives of thermoelectric aluminoborides.

  7. Liquid Phase Sintering of Highly Alloyed Stainless Steel

    DEFF Research Database (Denmark)

    Mathiesen, Troels

    1996-01-01

    of boride to AISI 316L type steels have previously been studied, but were found to be sensitive to intergranular corrosion due to formation of intermetallic phases rich in chromium and molybdenum. In order to improve this system further, new investigations have focused on the use of higher alloyed stainless......Liquid phase sintering of stainless steel is usually applied to improve corrosion resistance by obtaining a material without an open pore system. The dense structure normally also give a higher strength when compared to conventional sintered steel. Liquid phase sintrering based on addition...... steel as base material. The stainless base powders were added different amounts and types of boride and sintered in hydrogen at different temperatures and times in a laboratory furnace. During sintering the outlet gas was analyzed and subsequently related to the obtained microstructure. Thermodynamic...

  8. Peculiar structure and tensile strength of WB4: nonstoichiometric origin

    Directory of Open Access Journals (Sweden)

    Huiyang Gou

    2012-03-01

    Full Text Available Tungsten tetraboride (WB4 is experimentally considered as potentially superhard material and is therefore expected to have highly structural stability and enhanced resistance against plastic deformation and failure. The examinations of bond-deformation mechanism suggest a significantly soft bond-deformation pattern induced by ionic W-B bonding for nominal WB4 in experiments, largely responsible for the limitation of its strength and structural integrity. Computations on the structures and mechanical properties for WB4 show a novel thermodynamically favored MoB4-type phase with excellent mechanical properties and remarkable incompressibility along c direction. The illustrations of nonstoichiometry and x-ray diffraction spectra rationalize the experimental observation of nominal composition WB4 as defective tungsten borides (W1-xB3 (x0.25. The results provide new insight into the real structural and mechanical properties of tungsten borides.

  9. Evolution of microstructure of the new heat resistant 9 - 11 % Cr steels as a function of long term creep stressing

    Energy Technology Data Exchange (ETDEWEB)

    Kauffmann, F. [Stuttgart Univ. (Germany). MPA; Kern, T.U. [Siemens AG, Muehlheim (Germany). Energy Sector; Straub, S. [ALSTOM Power Systems GmbH, Mannheim (Germany); Mayer, K.H. [ALSTOM Power Systems GmbH, Nuernberg (Germany)

    2010-07-01

    The development of new creep resistant materials for higher temperatures in the field of energy generation is a key topic with high technological, economical and environmental interest. The strength and usability of typical materials in this area are 9 - 11 % Cr steels additional alloyed with Mo, W, V, Nb, N and B, which are governed by their microstructural features such as precipitations in the sub-micron range, the dislocation density, the subgrain sizes and in unfavorable cases with the formation of boride-particles. The evaluation of these features and the understanding of their correlation with the long-time creep properties is of pivotal interest in the development of improved materials. This paper will focus on two aspects: the correlation of the microstructure after long testing times with the corresponding creep properties and the measurement and possible quantification of borides in these steels. (orig.)

  10. Phase transformations in Mo-doped FINEMETs

    Energy Technology Data Exchange (ETDEWEB)

    Silveyra, Josefina M., E-mail: jsilveyra@fi.uba.a [Lab. de Solidos Amorfos, INTECIN, FIUBA-CONICET, Paseo Colon 850, (C1063ACV) Buenos Aires (Argentina); Illekova, Emilia; Svec, Peter; Janickovic, Dusan [Institute of Physics SAS, Dubravska cesta 9, 845 11 Bratislava (Slovakia); Rosales-Rivera, Andres [Laboratorio de Magnetismo y Materiales Avanzados, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Manizales (Colombia); Cremaschi, Victoria J. [Lab. de Solidos Amorfos, INTECIN, FIUBA-CONICET, Paseo Colon 850, (C1063ACV) Buenos Aires (Argentina)

    2010-06-15

    In this paper, the phase transformations occurring during the crystallization process of FINEMETs in which Nb has been gradually replaced by Mo have been studied by a variety of techniques including DSC, DTA, TGA, XRD and TEM. The thermal stability of the alloy was deteriorated as a consequence of Mo's smaller atomic size. The gradual replacement of Nb by Mo reduced the onset temperature of Fe-Si and of the borides. The Curie temperature of the amorphous phase slightly decreased from 594 K for x=0 to 587 K for x=3. The borides compounds Fe{sub 2}B and Fe{sub 23}B{sub 6} as well as the (Nb,Mo){sub 5}Si{sub 3} phase were found to precipitate in the second and third crystallization.

  11. Microstructural characterization aluminium alloys from the addition of boron; Caracterizacao microestrutural de ligas de aluminio a partir da adicao de boro

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, A.G.P.; Pipano, T.F.; Mota, M.A.; Mariano, N.A.; Ramos, E.C.T. [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil). Instituto de Ciencias e Tecnologia

    2014-07-01

    In the electrical industry, the aluminum becomes attractive because it has excellent characteristics for transmitting electricity. The liquid aluminum has in its composition transition elements (zirconium, titanium, vanadium and chromium) that interfere negatively on the quality of the product. The addition of aluminum-boron alloys have been used to remove transition metals through the formation of borides, enabling an increase in electrical conductivity. However, no detailed reports of reactions between boron, transition metals and primary aluminum engines. However, the objective is to determine the stoichiometric composition that enables an increase in electrical conductivity of an aluminum alloy. Samples with different concentrations of boron were characterized by optical emission spectrometry, electrical conductivity and X-ray diffraction. The addition of boron in excess reduces the time in the formation of borides, and enable an increase in electrical conductivity. (author)

  12. Phase equilibria in a ternary fullerenol-d(C60(OH)22-24)-SmCl3-H2O system at 25°C

    Science.gov (United States)

    Yur'ev, G. O.; Keskinov, V. A.; Semenov, K. N.; Charykov, N. A.

    2017-05-01

    The solubility in a ternary fullerenol-d (C60(OH)22-24)-SmCl3-H2O system at 25°C is studied via isothermal saturation in ampules. The solubility diagram is shown to be a simple eutonic one that consists of two branches corresponding to the crystallization of fullerenol-d (C60(OH)22-24 · 30H2O) and samarium(III) chloride SmCl3 · 6H2O crystallohydrates and contains one nonvariant eutonic point corresponding to saturation with both crystallohydrates. The long branch of C60(OH)22-24 · 30H2O crystallization shows the effect of fullerenol-d salting out of saturated solutions; in contrast, the short branch of SmCl3 · 6H2O crystallization shows the pronounced salting-in effect of samarium(III) chloride.

  13. Alkaline and alkaline earth metal phosphate halides and phosphors

    Science.gov (United States)

    Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John

    2012-11-13

    Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

  14. Reductive trapping of [(OC){sub 5}W-W(CO){sub 5}]{sup 2-} in a mixed-valent Sm{sup II/III} calix[4]pyrrolide sandwich

    Energy Technology Data Exchange (ETDEWEB)

    Deacon, Glen B.; Guo, Zhifang [School of Chemistry, Monash University, VIC (Australia); Junk, Peter C.; Wang, Jun [College of Science and Engineering, James Cook University, Townsville, QLD (Australia)

    2017-07-10

    Reduction of tungsten hexacarbonyl by the divalent samarium(II) complex [Sm{sub 2}(N{sub 4}Et{sub 8})(thf){sub 4}] ((N{sub 4}Et{sub 8}){sup 4-}=meso-octaethylcalix[4]pyrrolide) in toluene at ambient temperature gave the remarkable heteronuclear mixed-valent samarium(II/III)/tungsten complex [{(thf)_2Sm"I"I(N_4Et_8)Sm"I"I"I(thf)}{sub 2}{(μ-OC)_2W_2(CO)_8}], which features the trapping of a rare [W{sub 2}(CO){sub 10}]{sup 2-} anion with an unsupported W-W bond. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Preparation and dosimetry of radiotherapeutic particles for arthropaties; Preparacion y dosimetria de particulas radioterapeuticas para artropatias

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Z, M.A. [Departamento de Medicina Nuclear, Instituto Nacional de Pediatria (Mexico); Ferro F, G. [Departamento de Materiales Radiactivos, Instituto nacional de Investigaciones Nucleares, Salazar, Estado de Mexico C.P. 52045 (Mexico); Rivera M, T.; Azorin N, J. [Departamento de Fisica, UAM Iztapalapa, Mexico D.F. (Mexico)

    1999-07-01

    It was developed a new formulation of macro aggregates of Samarium 153 ({sup 153} Sm-MH) for the arthropaties treatment. The radio pharmaceutic was prepared by reaction of Samarium 153 chloride (SmCl{sub 3}) in aqueous environment with sodium boron hydride in NaOH 0.5 N. The microscopic analysis shown that the particles have an average size of 4% m (range 1-14 {mu} m). The velocity of sedimentation was 0.008 cm/min with high stability in vitro in human serum. The biological studies in healthy rabbits, shown that the complex is retained inside the articulation still eight days after of the administration of the radiopharmaceutical. Likewise, it is presented the data of absorbed dose in the different target organs, which was determined by thermoluminescent dosimetry (TLD) through the use of a REMCAL phantom (radiation equivalent manikin calibration). (Author)

  16. Ion-exchange separation of the rare earth elements by means of solution of ammonium phthalate and chloride

    Energy Technology Data Exchange (ETDEWEB)

    Hubicki, W.; Ozga, W. (Uniwersytet Marii Curie-Sklodowskiej, Lublin (Poland))

    1976-01-01

    A new method of ion exchange separation of lanthanons by the use of equimolar solution of ammonium phthalate and ammonium chloride as an eluent was elaborated. This method allows to separate light lanthanons and to obtain concentrate of samarium and heavy lanthanons. 99.99% Y/sub 2/O/sub 3/ was obtained from non-neodymium concentration with 47.4% efficiency. The influence of change in concentration and pH of eluent on the effectiveness of separation was examined. It was found that an increase in concentration of eluent and pH leads to quick separation of yttrium from samarium and heavy lanthanons. However, the efficiency of pure Y/sub 2/O/sub 3/ decreases distinctly.

  17. Large directional optical anisotropy in multiferroic ferroborate

    Science.gov (United States)

    Kuzmenko, A. M.; Dziom, V.; Shuvaev, A.; Pimenov, Anna; Schiebl, M.; Mukhin, A. A.; Ivanov, V. Yu.; Gudim, I. A.; Bezmaternykh, L. N.; Pimenov, A.

    2015-11-01

    One of the most fascinating and counterintuitive recent effects in multiferroics is directional anisotropy, the asymmetry of light propagation with respect to the direction of propagation. In such case the absorption in a material can be different for opposite directions. Besides absorption, different velocities of light for different directions of propagation may be also expected, which is termed directional birefringence. In this work, we demonstrate large directional anisotropy in multiferroic samarium ferroborate. The effect is observed for linear polarization of light in the range of millimeter wavelengths, and it survives down to low frequencies. The dispersion and absorption close to the electromagnon resonance can be controlled by external magnetic field and are fully suppressed in one direction. By changing the geometry of the external field, samarium ferroborate shows giant optical activity, which makes this material a universal tool for optical control: with a magnetic field as an external parameter it allows switching between two functionalities: polarization rotation and directional anisotropy.

  18. Structure et propriétés physiques de composés magnétiques de type RT12B6 et (Hf,Ta)Fe2 et leur dépendance en fonction de la pression (physique ou chimique) (R=élément de terre rare et T=élément de transition 3d)

    OpenAIRE

    Diop, Léopold Vincent Birane

    2014-01-01

    Our multidisciplinary study includes the synthesis of intermetallic compounds and the characterization of their structural and magnetic properties. Our work has focused on RT12B6 borides where R is a rare earth element or yttrium and T a 3d transition metal as well as (Hf, Ta)Fe2 Laves phases. In order to understand the physical properties of these compounds, we have implemented various external variables (temperature, magnetic field, pressure) as well as internal variables such as the chemic...

  19. On the development of a new pre-weld thermal treatment procedure for preventing heat-affected zone (HAZ) liquation cracking in nickel-base IN 738 superalloy

    Science.gov (United States)

    Ola, O. T.; Ojo, O. A.; Chaturvedi, M. C.

    2014-10-01

    Hot cracking in the heat-affected zone (HAZ) of precipitation strengthened nickel-base superalloys, such as IN 738, during fusion welding remains a major factor limiting reparability of nickel-base gas turbine components. The problem of HAZ intergranular cracking can be addressed by modifying the microstructure of the pre-weld material through thermal treatment, which requires significant understanding of the critical factors controlling cracking behaviour. The decomposition of Mo-Cr-W-and Cr-rich borides in the alloy, among other factors, has been observed to contribute significantly to non-equilibrium intergranular liquation and, hence, intergranular liquation cracking during welding. Gleeble physical simulation of HAZ microstructure has also shown that non-equilibrium liquation is more severe in the vicinity of decomposed borides in the alloy and can occur at temperatures as low as 1,150 °C. Although currently existing pre-weld heat treatments for IN 738 superalloy minimize the contributions of dissolution of second phases, including borides, to HAZ intergranular liquation, these heat treatments are not industrially feasible due to process-related difficulties. Therefore, a new industrially feasible and effective pre-weld thermal treatment process, designated as FUMT, was developed during the present research by controlling both the formation of borides and the segregation of boron at the grain boundaries in the pre-weld heat-treated material. This thermal treatment was observed to very significantly reduce intergranular HAZ cracking in welded IN 738 superalloy. The details of the development process and developed procedure are presented in this paper.

  20. Thermisch stabiler Multilayer-Spiegel fuer den EUV-Spektralbereich

    OpenAIRE

    Benoit, N.; Feigl, T.; Yulin, S.; Kaiser, N.

    2007-01-01

    WO2006066563 A UPAB: 20060724 NOVELTY - A multilayer mirror (1) has a number of alternating molybdenum layers (4) and silicon layers (3). A barrier layer (5) is placed on a number of boundary surfaces between the molybdenum layers and the silicon layers and contains a silicon nitride or a silicon boride. A high thermal stability, particularly a high long-time stability at temperatures of greater than 3000 deg. C with a simultaneously high degree of reflection of the multilayer mirror is achie...

  1. Platinum Group Coatings for Refractory Metals

    Science.gov (United States)

    1984-06-01

    molybdenum , tungsten, tantalum, niobium, rhenium or carbon/carbon must be used to fabricate the parts to withstand these temperatures. These materials and...layers (eg silicides, borides ) o Alloy coatings that form compact oxide layers (Ni and Co F based alloys) o Stable oxides that provide physical barriers...thermally etched) surface and seems to promote adhesion. Molybdenum rods 3mm in diameter were used as substrates during many of the runs where the

  2. Reactive Processing and Co-Extrusion of Ultra-High Temperature Ceramics and Composites

    Science.gov (United States)

    2006-02-28

    Faenza, Italy. Ultra-high temperature ceramics (UHTCs) are a unique class of materials with melting temperatures in excess of 3000’C. The borides ...composites with silicon carbide (SiC) and molybdenum disilicide (MoSi 2) were examined. Two main approaches were pursued: 1) the use of reactive processing...Diboride- Molybdenum Disilicide Ceramics," pp. 299-308 in Advances in Ceramic Matrix Composites IX, Ceramic Transactions, Volume 153, ed. by N.P. Bansal, J.P

  3. Demonstration of Shear Localization in Ultrafine Grained Tungsten Alloys via Powder Metallurgy Processing Route

    Science.gov (United States)

    2012-09-01

    which remained elastic during each experiment. Interfaces between the specimen and platens were lubricated with molybdenum disulfide (MoS2) grease to...of a di-tungsten boride (W2B) phase was not detected in the nW-B sample, but the low concentration of boron may have made this phase undetectable by...Further Studies on Rhenium Alloying Effects in Molybdenum , Tungsten, and Chromium, Battelle Memorial Inst., Columbus, Ohio, 1960. 20. Lassner, E

  4. Computer Modeling of Basic Physico-Chemical Processes for DSEC Composites of System LaB6-MeB2(MeTi, Zr, Hf) at Macro-, Meso- and Microstructure Scales

    Science.gov (United States)

    2010-07-15

    single crystals of borides of rare earth metals is performed by a few labs of the world - Japan, USA, Germany, Russia, Ukraine, and the methods of...software is developed on the base of experience gained in numerical multifractal analysis of images of structures of metals and alloys during a number...of experiment on blackening of separate white squares of carpet (one per image) were obtained. The program calculated all images; fractal dimension

  5. Method to produce catalytically active nanocomposite coatings

    Science.gov (United States)

    Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

    2016-02-09

    A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

  6. Magnetic properties (Communication arising): Parasitic ferromagnetism in a hexaboride?

    Science.gov (United States)

    Matsubayashi, K.; Maki, M.; Tsuzuki, T.; Nishioka, T.; Sato, N. K.

    2002-11-01

    Surprisingly for a compound with no magnetic element, Young et al. have observed ferromagnetism in calcium hexaboride (CaB6) doped with lanthanum (La) - the system has a ferromagnetic Curie temperature as high as 600 K, which is comparable to that of transition-metal ferromagnets such as iron (Fe). Here we show that high-temperature ferromagnetism in this CaB6 system is not intrinsic but that it is instead due to alien phases of iron and boride.

  7. Method to produce catalytically active nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

    2017-12-19

    A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

  8. Manhattan Project Technical Series The Chemistry of Uranium (I) Chapters 1-10

    Energy Technology Data Exchange (ETDEWEB)

    Rabinowitch, E. I. [Argonne National Laboratory (ANL), Argonne, IL (United States); Katz, J. J. [Argonne National Laboratory (ANL), Argonne, IL (United States)

    1946-09-30

    This constitutes Chapters 1 through 10. inclusive, of The Survey Volume on Uranium Chemistry prepared for the Manhattan Project Technical Series. Chapters are titled: Nuclear Properties of Uranium; Properties of the Uranium Atom; Uranium in Nature; Extraction of Uranium from Ores and Preparation of Uranium Metal; Physical Properties of Uranium Metal; Chemical Properties of Uranium Metal; Intermetallic Compounds and Alloy systems of Uranium; the Uranium-Hydrogen System; Uranium Borides, Carbides, and Silicides; Uranium Nitrides, Phosphides, Arsenides, and Antimonides.

  9. Hybrid fiber and nanopowder reinforced composites for wind turbine blades

    Directory of Open Access Journals (Sweden)

    Nikoloz M. Chikhradze

    2015-01-01

    Full Text Available The results of an investigation into the production of wind turbine blades manufactured using polymer composites reinforced by hybrid (carbon, basalt, glass fibers and strengthened by various nanopowders (oxides, carbides, borides are presented. The hybrid fiber-reinforced composites (HFRC were manufactured with prepreg technology by molding pre-saturated epoxy-strengthened matrix-reinforced fabric. Performance of the manufactured composites was estimated with values of the coefficient of operating condition (COC at a moderate and elevated temperature.

  10. Ionic liquid technology for recovery and separation of rare earths

    OpenAIRE

    Binnemans, Koen

    2015-01-01

    End-of-life neodymium-iron-boron and samarium-cobalt permanent magnets, fluorescent lamps and metal hydride batteries are valuable secondary resources of rare earths. These resources are characterised by relatively small volumes, but high concentrations of rare earths [1]. On the other hand, industrial process residues such as bauxite residue (red mud) and phosphogypsum contain low concentrations of rare earths, but are available in huge volumes [2]. Recovery of rare earths from end-of-life c...

  11. Ternary rare earth-lanthanide sulfides

    Science.gov (United States)

    Takeshita, Takuo; Gschneidner, Jr., Karl A.; Beaudry, Bernard J.

    1987-01-06

    A new ternary rare earth sulfur compound having the formula: La.sub.3-x M.sub.x S.sub.4 where M is a rare earth element selected from the group europium, samarium and ytterbium and x=0.15 to 0.8. The compound has good high-temperature thermoelectric properties and exhibits long-term structural stability up to 1000.degree. C.

  12. Structural and physical properties of Sm doped magnesium zinc ...

    Indian Academy of Sciences (India)

    2017-09-22

    Sep 22, 2017 ... Abstract. Samarium (Sm3+) doped magnesium zinc sulfophosphate glass system of composition (60–x)P2O5–20MgO–. 20ZnSO4–xSm2O3 (x = 0.0, 0.5, 1.0, 1.5 and 2.0 mol%) were synthesized using melt-quenching technique. The structure and physical properties of prepared glass samples were ...

  13. Structural aspects of displacive transformations: what can optical microscopy contribute? Dehydration of Sm2(C2O4)3·10H2O as a case study.

    Science.gov (United States)

    Matvienko, Alexander A; Maslennikov, Daniel V; Zakharov, Boris A; Sidelnikov, Anatoly A; Chizhik, Stanislav A; Boldyreva, Elena V

    2017-09-01

    For martensitic transformations the macroscopic crystal strain is directly related to the corresponding structural rearrangement at the microscopic level. In situ optical microscopy observations of the interface migration and the change in crystal shape during a displacive single crystal to single crystal transformation can contribute significantly to understanding the mechanism of the process at the atomic scale. This is illustrated for the dehydration of samarium oxalate decahydrate in a study combining optical microscopy and single-crystal X-ray diffraction.

  14. The growth and reactivity of the {Sm}/{Si(100)} interface

    Science.gov (United States)

    Onsgaard, J.; Christiansen, M.; Ørskov, F.; Godowski, P. J.

    1991-05-01

    The growth of the {Sm}/{Si(100)} interface is described and discussed in the context of the increasing experimental insight into lanthanide/semiconductor interfaces. Silicide formation takes place in the 1 to 5 monolayers coverage region. Different ordered structures, dependent on the initial coverage and temperature treatment, are observed. Oxygen adsorption and binding is strongly promoted, both when Sm is present at the surface and when oxygen reacts with a samarium-suicide film.

  15. Installation of electric generators on turbine engines

    Science.gov (United States)

    Demel, H. F.

    1983-01-01

    The installation of generators on turbine aircraft is discussed. Emphasis is placed on the use of the samarium cobalt generator. Potential advantages of an electric secondary power system at the engine level are listed. The integrated generator and the externally mounted generator are discussed. It is concluded that the integrated generator is best used in turbojet and low bypass ratio engines where there is no easy way of placing generators externally without influencing frontal areas.

  16. Fabrication of Material and Devices for Very High Density Information Storage.

    Science.gov (United States)

    1986-11-24

    crystal bismuth doped garnets , having properties equivalent to IPE grown materials,,’., onto gadolinium gallium garnet substrates. There was speculation... LPE onto0 (111)-.""’’ oriented calcium-, magnesium- or zirconium-substituted gadolinium, samarium or neodymium gallium /’’’ garnet substrates. Garnet ...properties of LPE garnetmusesit favor garnets a s a t arting poiut. ref og Vmagnetic and m g e-optical po et s o a- , pae d m u , alu inu-%, li

  17. Macrocyclic aminophosphonic acid complexes, their preparation, formulations and use; Fremgangsmaate for fremstilling av et makrocyklisk aminofosfonsyrekompleks eller et fysiologisk akseptabelt salt derav

    Energy Technology Data Exchange (ETDEWEB)

    Simon, J.; Wilson, D.A.; Garlich, J.R.; Troutner, D.E.

    1997-01-13

    Particle emitting radionuclides, e.g. Samarium-153, have been complexed with certain macrocyclic aminophosphonic acids wherein the nitrogen and phosphorus are interconnected by an alkylene group or substituted alkylene group. A composition is now disclosed which comprises a complex having a macrocyclic aminophosphonic acid, containing 1,4,7,10-tetraazycyclododecane as the macrocyclic moiety, or a physiologically, acceptable salt thereof, wherein the nitrogen and phosphorus are interconnected by an alkylene or substituted alkylene radical. 10 tabs.

  18. Effect of Flake Thickness on Coercivity of Nanocrystalline SmCo5 Bulk Prepared from Anisotropic Nanoflake Powder (Postprint)

    Science.gov (United States)

    2016-08-23

    flake thickness. 15. SUBJECT TERMS rare earth magnets , samarium cobalt magnets , permanent magnets 16. SECURITY CLASSIFICATION OF: 17...nanoflakes have attractive magnetic properties ; coercivity of up to 21 kOe and maximum energy product of up to 22 MGOe.9 Thus, the nanoflake powders...less reported on correlation between nanoflake morphology and final properties of the SmCo5 bulk magnets . In this study, we prepared SmCo5 nanoflakes

  19. Cross sections of deuteron induced reactions on $^{nat}$Sm for production of the therapeutic radionuclide $^{145}$Sm and $^{153}$Sm

    OpenAIRE

    Tárkányi, F.; Hermanne, A.; Takács, S.; Ditrói, F.; Csikai, J.; Ignatyuk, A. V.

    2014-01-01

    At present, targeted radiotherapy (TR) is acknowledged to have great potential in oncology. A large list of interesting radionuclides is identified, including several radioisotopes of lanthanides, amongst them $^{145}$Sm and $^{153}$Sm. In this work the possibility of their production at a cyclotron was investigated using a deuteron beam and a samarium target. The excitation functions of the $^{nat}$Sm(d,x)$^{145153}$Sm reactions were determined for deuteron energies up to 50 MeV using the st...

  20. Microstructure characteristics of high borated stainless steel fabricated by hot-pressing sintering

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xuan; Wang, Mingjia, E-mail: mingjiawangysu@126.com; Zhao, Hongchang

    2016-04-25

    The present study investigated the microstructure of powder metallurgy (P/M) high borated stainless steel through hot-pressing sintering in a temperature range of 1000–1150 °C within 30 min under 30 MPa. Microstructure and phase examinations were carried out by applying scanning electron microscope, electron backscatter diffraction and X-ray diffraction analysis. The results of as-atomized powders demonstrated that many powders kept egg-type structure with an austenite outer layer and the eutectic borides were much finer than those in traditional cast products. Microstructure studies revealed that borides suffered Ostwald ripening and were significantly influenced by the sintering temperature. Orientation maps indicated that the inter-particle contact areas consisted of equiaxed grains and the regions consisting of large elongated grains partly inherited the microstructure characteristics of as-atomized powder particles. Furthermore, the mechanisms governing the morphological changes in microstructure were discussed. - Highlights: • Near-complete densification could be obtained through hot-pressing sintering. • There was no phase transformation and present phases were M{sub 2}B and austenite. • Borides suffered Ostwald ripening and were significantly influenced by temperature. • Inter-particle contact areas consisted of equiaxed grains for recrystallization. • Deformation-free zones exhibited elongated grains for dendritic arms coarsening.

  1. Peculiar features of metallurgical processes at plasma-arc spraying of coatings, made of steel wire with powder fillers B4C and B4C+ZrO2

    Directory of Open Access Journals (Sweden)

    Георгій Михайлович Григоренко

    2016-11-01

    Full Text Available The interaction of metallurgical processes occurring in plasma-arc spraying between the steel shell and the carbide fillers of B4C and B4C cored wires with the addition of nanocrystalline ZrO2 powder has been analyzed. Iron-boron compounds alloyed with carbon are formed in ingots as a result of ferritiс coating of wire interacrion with fillers while the ferritic matrix contains boride and carboboride eutectics. Average microhardness of the carboboride compounds and the matrix is high – 17,78; 16,40 and 8,69; 9,95 GPa for the ingots with с B4C and B4C+ZrO2 respectively. The best quality coatings with low porosity (~1%, lamellar structure consisting of ferrite matrix reinforced with dispersed Fe borides, were obtained at a higher heat input (plasmatron current 240-250 A. The average amount of oxides in the coatings makes 15%. 0,5% addition of nanopowder ZrO2 accelerates dispersed iron-boron compounds forming, promotes their uniform distribution in the structure and improves coating microhardness up to 7,0 GPa. Application of the differential thermal analysis method to simulate the interaction processes between the steel shell and the filler during the heating of wire in the shielding gas makes it possible to promote formation of new phases (borides and carboborides of iron and to predict the phase composition of the coatings

  2. Nanostructuring of Strontium Hexaboride via Lithiation.

    Science.gov (United States)

    Ramachandran, Roshini; Salguero, Tina T

    2017-12-19

    We describe the top-down nanostructuring of a metal boride using SrB6 as an example. To accomplish this transformation, we demonstrate (1) the direct lithiation of a metal boride using n-butyllithium and then (2) the reactive disassembly of Li-SrB6 into nanoparticles using water. The identity of the Li-SrB6 intermediate, a mixture of Li2B6, LixSr1-2xB6, and SrB6 phases, was established by powder X-ray diffraction (PXRD), solid-state 11B and 7Li NMR, transmission electron microscopy, selected-area electron diffraction, and scanning electron microscopy. The necessary 2Li+/Sr2+ substitution is enabled by cation mobility within the hexaboride lattice. The subsequent reaction with water results in Li2B6 decomposition and the release of <100 nm SrB6 nanoparticles, which were characterized by PXRD, solid-state 11B and 7Li NMR, and high-resolution TEM. This chemistry opens new solution-based modification and processing options for metal borides.

  3. Microstructure and Mechanical Properties of Wide-gap Brazed Joints of K465 Alloy Using Cobalt-base Brazing Alloy

    Directory of Open Access Journals (Sweden)

    PAN Hui

    2017-06-01

    Full Text Available Vacuum brazing of K465 superalloy was carried out by using Co45NiCrWB cobalt-base filler metal at 1220 ℃ for different holding time, and the joint clearance was 0.5 mm pre-filled with FGH95 nickel-base superalloy powder. The effect of the structural constitution of brazed different holding time of temperature on the brazed joint microstructure and properties. The results show that the brazing seam is composed of alloy powder particles and borides among them. It is two-phase structure of γ and γ' with a few small blocks of borides in the powder particles, and there exists phases rich in Cr, W and Nb elements. The powder particles are growing along the holding time during the brazing process, while their combination is expanded. It is good for stress rapture properties of joints that borides was fine in brazing seam with more superalloy powder and proper holding time. And the joints brazed for 30-60 min show higher stress rapture properties.

  4. Hardness and wear resistance of steel-based surface composites fabricated with Fe-based metamorphic alloy powders by high-energy electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyuhong [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Nam, Duk-Hyun [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, Sunghak [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)]. E-mail: shlee@postech.ac.kr; Kim, Choongnyun Paul [Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2006-07-25

    In this study, steel-based surface composites were fabricated with Fe-based metamorphic alloy powders by high-energy electron beam irradiation, and their microstructure, hardness, and wear resistance were investigated. Two kinds of Fe-based metamorphic powders were deposited on a plain carbon steel substrate, and then electron beam was irradiated on these powders to fabricate one-layered surface composites. Two-layered surface composites were also fabricated by irradiating electron beam again onto the powders deposited on the one-layered surface composites. The composite layers of 2.6-3.1 mm in thickness were homogeneously formed without defects, and contained a large amount (up to 64 vol.%) of Cr{sub 2}B or Cr{sub 1.65}Fe{sub 0.35}B{sub 0.96} borides in the Cr{sub 0.19}Fe{sub 0.7}Ni{sub 0.11} or martensite matrix. Since the hardness and wear resistance of the surface composite layers were directly influenced by hard borides, they were two to four times greater than those of the steel substrate. These borides also played a role in improving the high-temperature hardness because they are insoluble and thermally stable even at high temperatures. These findings suggested that various applications of the fabricated surface composites to materials requiring high resistance to heat and abrasion were expected.

  5. Boron: Enabling Exciting Metal-Rich Structures and Magnetic Properties.

    Science.gov (United States)

    Scheifers, Jan P; Zhang, Yuemei; Fokwa, Boniface P T

    2017-09-19

    Boron's unique chemical properties and its reactions with metals have yielded the large class of metal borides with compositions ranging from the most boron-rich YB66 (used as monochromator for synchrotron radiation) up to the most metal-rich Nd2Fe14B (the best permanent magnet to date). The excellent magnetic properties of the latter compound originate from its unique crystal structure to which the presence of boron is essential. In general, knowing the crystal structure of any given extended solid is the prerequisite to understanding its physical properties and eventually predicting new synthetic targets with desirable properties. The ability of boron to form strong chemical bonds with itself and with metallic elements has enabled us to construct new structures with exciting properties. In recent years, we have discovered new boride structures containing some unprecedented boron fragments (trigonal planar B4 units, planar B6 rings) and low-dimensional substructures of magnetically active elements (ladders, scaffolds, chains of triangles). The new boride structures have led to new superconducting materials (e.g., NbRuB) and to new itinerant magnetic materials (e.g., Nb6Fe1-xIr6+xB8). The study of boride compounds containing chains (Fe-chains in antiferromagnetic Sc2FeRu5B2), ladders (Fe-ladders in ferromagnetic Ti9Fe2Rh18B8), and chains of triangles (Cr3 chains in ferrimagnetic and frustrated TiCrIr2B2) of magnetically active elements allowed us to gain a deep understanding of the factors (using density functional theory calculations) that can affect magnetic ordering of such low-dimensional magnetic units. We discovered that the magnetic properties of phases containing these magnetic subunits can be drastically tuned by chemical substitution within the metallic nonmagnetic network. For example, the small hysteresis (measure of magnetic energy storage) of Ti2FeRh5B2 can be successively increased up to 24-times by gradually substituting Ru for Rh, a result that was

  6. Removal of Vanadium from Molten Aluminum—Part III. Analysis of Industrial Boron Treatment Practice

    Science.gov (United States)

    Khaliq, Abdul; Akbar Rhamdhani, Muhammad; Brooks, Geoffrey A.; Grandfield, John

    2014-04-01

    Transition metal impurities (V, Ti, Zr, and Cr) reduce the electrical conductivity of smelter grade aluminum. These impurities are removed in the form of their borides by reacting with added Al-B master alloys i.e., boron treatment. Although, boron treatment is widely used for the production of high purity aluminum alloys in casthouse the fundamental understanding is lacking and published industrial data are limited. In the current study, industrial trials on the removal of impurities were conducted at one of the high purity aluminum alloys producers in Australasia. Kinetics analysis revealed that the rate of reaction is controlled by the mass transfer of impurities in the bulk melt. The measured mass transfer coefficient ( k m) of V and Ti were 1.1 × 10-4 and 2.6 × 10-4 m/s respectively, in the naturally stirred molten aluminum. The rate of V and Ti removal was faster compared to Zr and Cr during the boron treatment of smelter grade aluminum. Mass balance analysis revealed that 70 wt pct of V and Ti combined as borides in the first hour of the total 12 hours of boron treatment process. The calculated amount of un-reacted B was approximately 25.5 wt pct of initial amount added that remained in the final alloy. There was no evidence of boride rings formation, although partially dissolved AlB12 particles were observed under scanning electron microscope. Finally, implications for industrial practice are discussed for the improvement of current boron treatment process that include changing the source of boron, multiple stage addition of boron and better stirring of the molten aluminum.

  7. Liquid Phase Sintering of Boron-Containing Powder Metallurgy Steel with Chromium and Carbon

    Science.gov (United States)

    Wu, Ming-Wei; Fan, Yu-Chi; Huang, Her-Yueh; Cai, Wen-Zhang

    2015-11-01

    Liquid phase sintering is an effective method to improve the densification of powder metallurgy materials. Boron is an excellent alloying element for liquid phase sintering of Fe-based materials. However, the roles of chromium and carbon, and particularly that of the former, on liquid phase sintering are still undetermined. This study demonstrated the effects of chromium and carbon on the microstructure, elemental distribution, boride structure, liquid formation, and densification of Fe-B-Cr and Fe-B-Cr-C steels during liquid phase sintering. The results showed that steels with 0.5 wt pct C densify faster than those without 0.5 wt pct C. Moreover, although only one liquid phase forms in Fe-B-Cr steel, adding 0.5 wt pct C reduces the formation temperature of the liquid phase by about 50 K (°C) and facilitates the formation of an additional liquid, resulting in better densification at 1473 K (1200 °C). In both Fe-B-Cr and Fe-B-Cr-C steels, increasing the chromium content from 1.5 to 3 wt pct raises the temperature of liquid formation by about 10 K (°C). Thermodynamic simulations and experimental results demonstrated that carbon atoms dissolved in austenite facilitate the eutectic reaction and reduce the formation temperature of the liquid phase. In contrast, both chromium and molybdenum atoms dissolved in austenite delay the eutectic reaction. Furthermore, the 3Cr-0.5Mo additive in the Fe-0.4B steel does not change the typical boride structure of M2B. With the addition of 0.5 wt pct C, the crystal structure is completely transformed from M2B boride to M3(B,C) boro-carbide.

  8. Identification of novel sulfur-containing steroids in sediments and petroleum: probable incorporation of sulfur into δ 5,7-sterols during early diagenesis

    Science.gov (United States)

    Sinninghe Damsté, Jaap S.; Schouten, Stefan; de Leeuw, Jan W.; van Duin, Adri C. T.; Geenevasen, Jan A. J.

    1999-01-01

    A novel sulfur-containing sterane, 4α,7α-epithio-5β-cholestane, has been identified in a sediment extract from the Miocene Northern Apennines marl (Italy) after its isolation by column chromatography and high pressure liquid chromatography. The compound has been characterised by GC-MS and mild Nickel boride desulfurisation and one and two-dimensional 1H NMR techniques. C 27-C 29 homologs have been detected in sediment extracts of three different formations and in one petroleum sample. These sulfur-containing steroids are probably formed by an intramolecular reaction of inorganic sulfides with early diagenetic products of Δ 5,7-sterols.

  9. Material comprising two different non-metallic parrticles having different particle sizes for use in solar reactor

    Science.gov (United States)

    Klausner, James F.; Momen, Ayyoub Mehdizadeh; Al-Raqom, Fotouh A.

    2017-10-03

    Disclosed herein is a composite particle comprising a first non-metallic particle in which is dispersed a second non-metallic particle, where the first non-metallic particle and the second non-metallic particle are inorganic; and where a chemical composition of the first non-metallic particle is different from a chemical composition of the second non-metallic particle; and where the first non-metallic particle and the second non-metallic particle are metal oxides, metal carbides, metal nitrides, metal borides, metal silicides, metal oxycarbides, metal oxynitrides, metal boronitrides, metal carbonitrides, metal borocarbides, or a combination thereof.

  10. High temperature solar energy absorbing surfaces

    Science.gov (United States)

    Schreyer, J.M.; Schmitt, C.R.; Abbatiello, L.A.

    A solar collector having an improved coating is provided. The coating is a plasma-sprayed coating comprising a material having a melting point above 500/sup 0/C at which it is stable and selected from the group of boron carbide, boron nitride, metals and metal oxides, nitrides, carbides, borides, and silicates. The coatings preferably have a porosity of about 15 to 25% and a thickness of less than 200 micrometers. The coatings can be provided by plasma-spraying particles having a mean diameter of about 10 to 200 micrometers.

  11. Anti-scratch AlMgB14 Gorilla® Glass coating

    Science.gov (United States)

    Putrolaynen, V. V.; Grishin, A. M.; Rigoev, I. V.

    2017-10-01

    Hard aluminum-magnesium boride (BAM) films were fabricated onto Corning® Gorilla® Glass by radio-frequency magnetron sputtering of a single stoichiometric AlMgB14 target. BAM films exhibit a Vickers hardness from 10 to 30 GPa and a Young's modulus from 80 to 160 GPa depending on applied loading forces. Deposited hard coating increases the critical load at which glass substrate cracks. The adhesion energy of BAM films on Gorilla® Glass is 6.4 J/m2.

  12. Foreword

    Science.gov (United States)

    Manghnani, Murli H.

    2015-09-01

    The 18th International Symposium on Boron, Borides and Related Materials was held in Hawaii Prince Hotel Waikiki, Honolulu, Hawaii, USA on August 31 to September 5, 2014 (ISBB 2014). A booklet of the Program and Abstracts prepared for the Symposium served as an important record of the scientific papers presented as oral paper (68) and as posters (53). The wide range of contributions in various areas of inter-disciplinary research in boron-related materials, and the discussions during the sessions, demonstrated impressive advancements and offer many future opportunities for individual as well as collaborative endeavors globally.

  13. Incoherent x-ray emission of titanium diboride at the boron site

    Energy Technology Data Exchange (ETDEWEB)

    Ederer, D.L.; Winarski, R.; Ek, J. van [Tulane Univ., New Orleans, LA (United States)] [and others

    1997-04-01

    This group has made a study of a large number of transition metal diborides and hexaborides. As an example they would like to consider one of them. This class of compounds are of technical interest because they are quite hard, metallic, and chemically stable, and have high melting points. In addition to the technical importance of the borides, the group is interested in compounds of this type because of the very strong 1s {r_arrow} p* resonance that has been observed and associated with the boron atom.

  14. A Study of Soil Tillage Tools from Boronized Sintered Iron

    Science.gov (United States)

    Yazici, A.; Çavdar, U.

    2017-03-01

    Acomparative analysis of the properties of boronized sintered iron and quenched steels 30MnB5, 28MnCrB5 used for making soil tillage tools is performed. The microstructure, phase composition, hardness and strength characteristics of the materials are studied. The composition of the boride phase formed in the sintered iron after boronizing is determined by an x-ray method. The losses to abrasive wear are evaluated with the help of a device containing a special bin with a sample of abrasive soil.

  15. In-situ Formation of Reinforcement Phases in Ultra High Temperature Ceramic Composites

    Science.gov (United States)

    Stackpoole, Margaret M (Inventor); Gasch, Matthew J (Inventor); Olson, Michael W (Inventor); Hamby, Ian W. (Inventor); Johnson, Sylvia M (Inventor)

    2013-01-01

    A tough ultra-high temperature ceramic (UHTC) composite comprises grains of UHTC matrix material, such as HfB.sub.2, ZrB.sub.2 or other metal boride, carbide, nitride, etc., surrounded by a uniform distribution of acicular high aspect ratio reinforcement ceramic rods or whiskers, such as of SiC, is formed from uniformly mixing a powder of the UHTC material and a pre-ceramic polymer selected to form the desired reinforcement species, then thermally consolidating the mixture by hot pressing. The acicular reinforcement rods may make up from 5 to 30 vol % of the resulting microstructure.

  16. Ab initio investigation of Al/Mo2B interfacial adhesion

    OpenAIRE

    SI ABDELKADER, H.; Faraoun, H.I.

    2011-01-01

    First-principles calculations were performed to study the adhesion and the interfacial electronic structure of aluminum/molybdenum semi-boride (Al/Mo2B) interface. The work of adhesion (Wad) was calculated for both terminations of the Mo2B surface and it was found that Mo-terminated has larger Wad than the B-terminated one. It was shown that interfacial Al and B atoms form polar covalent bonds, while bonding of interfacial Al and Mo atoms mainly presents metallic character. Computational M...

  17. Synthesis and Characterization of Boron Nitride and Molybdenum Nitride Multi-Walled Nanotubes Using Liquid Plasma Arc Discharge

    Science.gov (United States)

    Holliday, Roger; Falvo, Mike; Washburn, Sean; Superfine, Rich

    2001-11-01

    We will present results on synthesis of Boron Nitride and Molybdenum Nitride nanotubes using the liquid nitrogen plasma-arc discharge method previously reported for carbon nanotubes synthesis[1]. We created a 60-100A/20-40V arc across electrodes of Hafnium Boride and Molybdenum Sulfide in a liquid nitrogen atmosphere. Nanotube geometry, nano-structure and composition characterization using TEM and EDAX will be presented. Progress in electronic and mechanical characterization as well as our incorporation of these nanotubes in to novel NEMS devices will be discussed. [1] M. Ishigami, J. Cummings, A. Zettl, S. Chen. Chemical Physical Letters 319 (2000) 457-459.

  18. Boron Nitride nanotube synthesis using liquid arc discharge

    Science.gov (United States)

    Holliday, Roger; Falvo, Mike; Washburn, Sean; Superfine, Richard

    2002-03-01

    We will present results on synthesis of Boron Nitride nanotubes using the liquid nitrogen plasma-arc discharge method previously reported for carbon nanotubes synthesis[1]. We created a 60-100A/20-40V arc across electrodes of Hafnium Boride and Molybdenum Sulfide in a liquid nitrogen atmosphere. Nanotube geometry, nano-structure and composition characterization using TEM and EDAX will be presented. Progress in electronic and mechanical characterization as well as our incorporation of these nanotubes in to novel NEMS devices will be discussed. [1] M. Ishigami, J. C., A. Zettl, S. Chen . Chemical Physical Letters 319 (2000),pp.457-459.

  19. Molten Boron Phase-Change Thermal Energy Storage: Containment and Applicability to Microsatellites (Draft)

    Science.gov (United States)

    2011-06-01

    likely since molybdenum borides become unstable below the desired experimental temperatures.42 Sample contamination through the reaction of molten...3643 0.134 0.0804 0.284 Rhenium 3453 0.15 0.09 0.325 Boron Nitride 3273 1.99 1.194 --- BeO 3010 2.43 1.458 3.41 Molybdenum 2890 0.255 0.153 0.391...Ruthenium 2607 381 117 Iridium 2739 213 147 Niobium 2750 323 53.7 Molybdenum 2896 390 138 American Institute of Aeronautics and Astronautics

  20. Prediction on technetium triboride from first-principles calculations

    Science.gov (United States)

    Miao, Xiaojia; Xing, Wandong; Meng, Fanyan; Yu, Rong

    2017-02-01

    Taking the Tc-B binary system as an example, here we report the first-principles prediction on new phases of technetium borides, TcB3, which has an unprecedented stoichiometry. Crystal structures, phase stability, electronic properties and mechanical properties of TcB3 have been investigated using first-principles calculations. The hexagonal P 6 bar m 2 structure (No.187) TcB3 with a high value of hardness (29 GPa) is energetically stable against decomposition into other compounds under pressures above 4 GPa, indicating that TcB3 can be synthesized above this pressure.

  1. An Exploration of Several Structural Measurement Techniques for Usage with Functionally Graded Materials

    Science.gov (United States)

    2006-12-01

    regarding free and forced vibrations by Yang and Shen found that at elevated temperatures, when considering FGMs in relation to an isotropic substance, FGMs ... FGM …………………………………………………… 30 12. ’Strong’ functionally graded beam after testing…………………………... 31 13. Strain gauge data for specimens F05 and F10...Member) date ii AFIT/GAE/ENY/07-D03 Abstract Titanium / titanium boride functionally graded 6”x1”x1” beams were subjected to a four

  2. Modeling the mechanical behavior of ceramic and heterophase structures manufactured using selective laser sintering and spark plasma sintering

    Science.gov (United States)

    Skripnyak, Vladimir A.; Skripnyak, Evgeniya G.; Skripnyak, Vladimir V.; Vaganova, Irina K.

    A model for predicting mechanical properties of ultra-high temperature ceramics and composites manufactured by selective laser sintering (SLS) and spark plasma sintering (SPS) under shock loading is presented. The model takes into account the porous structure, the specific volume and average sizes of phases, and the temperature of sintering. Residual stresses in ceramic composites reinforced with particles of refractory borides, carbides and nitrides after SLS or SPS were calculated. It is shown that the spall strength of diboride-zirconium matrix composites can be increased by the decreasing of porosity and the introduction of inclusions of specially selected refractory strengthening phases.

  3. A statistical analysis of the initial biodistribution of {sup 153}Sm-EDTMP in a canine

    Energy Technology Data Exchange (ETDEWEB)

    Galiano, Eduardo [Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, Ont., P3E 2C6 (Canada)]. E-mail: egalianoriveros@laurentian.ca; Stradiotto, Marco [Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, Ont., P3E 2C6 (Canada)

    2005-07-01

    {sup 153}Sm (t{sub 1/2}=46h) emits a 103keV gamma photon and two medium-energy beta particles. Five mCi of Samarium-153 ethylenediaminetetramethylenephosphonic acid ({sup 153}Sm-EDTMP) were administered to a clinically normal dog and whole body scans were obtained at 15min, 2h, and 24h post-injection (PI). Regions of interest (ROIs) were drawn representing abdomen, knee, rib, vertebral bodies, bladder, kidney, and liver, in each image. For each ROI, the mean intensity and standard deviation were computed, and a histogram was created. Clinically significant increased uptakes were found in liver and kidney.

  4. Coprecipitation experiment with Sm hydroxide using a multitracer produced by nuclear spallation reaction: A tool for chemical studies with superheavy elements.

    Science.gov (United States)

    Kasamatsu, Yoshitaka; Yokokita, Takuya; Toyomura, Keigo; Shigekawa, Yudai; Haba, Hiromitsu; Kanaya, Jumpei; Huang, Minghui; Ezaki, Yutaka; Yoshimura, Takashi; Morita, Kosuke; Shinohara, Atsushi

    2016-12-01

    To establish a new methodology for superheavy element chemistry, the coprecipitation behaviors of 34 elements with samarium hydroxide were investigated using multitracer produced by a spallation of Ta. The chemical reactions were rapidly equilibrated within 10s for many elements. In addition, these elements exhibited individual coprecipitation behaviors, and the behaviors were qualitatively related to their hydroxide precipitation behaviors. It was demonstrated that the ammine and hydroxide complex formations of superheavy elements could be investigated using the established method. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Radiological response of lanthanum guiding seeds in brachytherapy implants; Resposta radiologica de sementes guia de lantanio em implantes braquiterapicos

    Energy Technology Data Exchange (ETDEWEB)

    Silva, L.S.R.; Machado, E.D.P., E-mail: lais26@globo.com [Centro Federal de Educacao Tecnologica de Minas Gerais, Belo Horizonte, MG (Brazil). Departamento de Engenharia de Materiais; Campos, T.P.R. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Roberto, W.S. [Centro Federal de Educacao Tecnologica de Minas Gerais, Belo Horizonte, MG (Brazil). Departamento de Fisica e Matematica

    2013-08-15

    Ceramic seeds with La-139 incorporated were synthesized to be used as radiological guides in brachytherapy implants. The synthesis was performed based on the sol-gel method. The seeds were subjected to characterization by Scanning Electron Microscopy, X-ray diffraction and Energy-Dispersive X-ray Spectroscopy. Furthermore, the contrast from a radiographic film was evaluated to lanthanum, samarium and holmium seeds. Radiological response on a phantom at different depths with lanthanum seeds and metal seeds was also investigated. Based on the values of contrast, the synthesized lanthanum seeds can be considered efficient as radiological guides when implanted together with pure Ho-165 and Sm-152 seeds. (author)

  6. Understanding the photoluminescence characteristics of Eu{sup 3+}-doped double-perovskite by electronic structure calculation

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Binita [St. Paul’s Cathedral Mission College, 33/1Raja Rammohan Roy Road, Kolkata 700009 (India); Halder, Saswata; Sinha, T. P. [Department of Physics, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009 (India); Das, Sayantani [Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700009 (India)

    2016-05-23

    Europium-doped luminescent barium samarium tantalum oxide Ba{sub 2}SmTaO{sub 6} (BST) has been investigated by first-principles calculation, and the crystal structure, electronic structure, and optical properties of pure BST and Eu-doped BST have been examined and compared. Based on the calculated results, the luminescence properties and mechanism of Eu-doped BST has been discussed. In the case of Eu-doped BST, there is an impurity energy band at the Fermi level, which is formed by seven spin up energy levels of Eu and act as the luminescent centre, which is evident from the band structure calculations.

  7. Geochronology and structuring of the Ceara State: Borborema Province northwestern part, NE Brazil; Geocronologia e estruturacao do estado do Ceara: NW da provincia Borborema, NE, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Fetter, A.; Van Schmus, W.R. [Kansas Univ., Lawrence, KS (United States). Dept. of Geology; Santos, Ticiano J. Saraiva dos [UNESP, Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas; Arthaud, M.; Nogueira Neto, J. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Geologia

    1997-12-31

    The work confirms that the geochronological new data U/Pb in zircon and Samarium/Neodymium from the Ceara State furnished a refined chronology of the geological activity in the NW part of the Borborema Province, indicating an evolutive history since 2,78 Ga and 532 Ma. Furthermore, these data facilitated the different crust domain outlines in the region, putting age maximum limits in the pre-brasilianas supracrusts rocks deposition, and evidencing the epoch and duration of the Brasiliano magmatism and metamorphism in the northwest part of the State

  8. Structural aspects of displacive transformations: what can optical microscopy contribute? Dehydration of Sm2(C2O43·10H2O as a case study

    Directory of Open Access Journals (Sweden)

    Alexander A. Matvienko

    2017-09-01

    Full Text Available For martensitic transformations the macroscopic crystal strain is directly related to the corresponding structural rearrangement at the microscopic level. In situ optical microscopy observations of the interface migration and the change in crystal shape during a displacive single crystal to single crystal transformation can contribute significantly to understanding the mechanism of the process at the atomic scale. This is illustrated for the dehydration of samarium oxalate decahydrate in a study combining optical microscopy and single-crystal X-ray diffraction.

  9. Synthesis and application of a new fluorous-tagged ammonia equivalent

    DEFF Research Database (Denmark)

    Nielsen, Simon Dalsgaard; Smith, Garrick; Begtrup, Mikael

    2010-01-01

    A novel fluorous-tagged ammonia equivalent has been developed. It is based on a nitrogen-oxygen bond, which can be cleaved in a traceless manner by a molybdenum complex or samarium diiodide. The application in the synthesis of ureas, amides, sulfonamides, and carbamates is described. The scope of...... of the fluorous N--O linker is exemplified by the synthesis of itopride, a drug used for the treatment of functional dyspepsia. Itopride was synthesized with the aid of fluorous purification methods and the product was isolated in good overall yield, with high purity....

  10. Synthesis and application of a new fluorous-tagged ammonia equivalent.

    Science.gov (United States)

    Nielsen, Simon D; Smith, Garrick; Begtrup, Mikael; Kristensen, Jesper L

    2010-04-19

    A novel fluorous-tagged ammonia equivalent has been developed. It is based on a nitrogen-oxygen bond, which can be cleaved in a traceless manner by a molybdenum complex or samarium diiodide. The application in the synthesis of ureas, amides, sulfonamides, and carbamates is described. The scope of the fluorous N-O linker is exemplified by the synthesis of itopride, a drug used for the treatment of functional dyspepsia. Itopride was synthesized with the aid of fluorous purification methods and the product was isolated in good overall yield, with high purity. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Jaderné kolektivní stupně volnosti a Skyrme funkcionál

    OpenAIRE

    Božík, Daniel

    2010-01-01

    Title: Energy functional theories in nuclear physics Author: Daniel Božík Department: Institute of Particle and Nuclear Physics of Charles University Supervisor: prof. RNDr. Jan Kvasil, DrSc. Supervisor's e-mail address: Abstract: In the present work we study the giant resonances of the chain of even-even samarium nuclei 144−154 Sm. The numerical calculations are provided by a chain of numer- ical codes. Mean field is calculated by the HFB method for the Skyrme d...

  12. Geochronology Intermediary Laboratory implantation at the Rio Grande do Norte Federal University: the dating of the Serrinha Granitoid (RN) and the correlate Brasiliana extensional deformation; Implantacao do Laboratorio Intermediario de Geocronologia na UFRN: a datacao do granitoide de Serrinha (RN) e da deformacao extensional brasiliana correlata

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Maria Helena F.; Sa, Emanuel F. Jardim de; Souza, Zorano S. [Pernambuco Univ., Recife, PE (Brazil). Nucleo de Pesquisa em Geodinamica e Geofisica; Mendes, Franklin S. [Pernambuco Univ., Recife, PE (Brazil). Curso de Quimica; Ramalho, Karlos A.C. [Pernambuco Univ., Recife, PE (Brazil). Curso de Geologia

    1997-12-31

    The article describes the activities developed by the Geochronology Intermediary Laboratory at the Federal University of the Rio Grande do Norte, a Brazilian university, where there were the preoccupation of establishing strategies for a geochronological development. It relates the Rubidium-Strontium (Rb/Sr) and Samarium-Neodymium (Sm/Nd) methods, describing the analysis realized in these methodologies. Afterward, it presents the geological and petrographic situation of the Granitoide de Serrinha, located at Rio Grande do Norte State, Brazil and its geochronological data 8 refs., 2 figs.

  13. ACR-ASTRO practice guideline for the performance of therapy with unsealed radiopharmaceutical sources.

    Science.gov (United States)

    Henkin, Robert E; Del Rowe, John D; Grigsby, Perry W; Hartford, Alan C; Jadvar, Hossein; Macklis, Roger M; Parker, J Anthony; Wong, Jeffrey Y C; Rosenthal, Seth A

    2011-08-01

    This guideline is intended to guide appropriately trained and licensed physicians performing therapy with unsealed radiopharmaceutical sources. Adherence to this guideline should help to maximize the efficacious use of these procedures, maintain safe conditions, and ensure compliance with applicable regulations. The topics dealt with in this guideline include indications for the use of iodine-131, both for the treatment of hyperthyroidism and thyroid carcinoma. In addition, indications for other less common procedures include those for the use of phosphorous-32 in its liquid and colloidal forms, strontium-89, samarium-153, and the use of Y-90 antibodies.

  14. Accumulation of rare earth elements by siderophore-forming Arthrobacter luteolus isolated from rare earth environment of Chavara, India.

    Science.gov (United States)

    Emmanuel, E S Challaraj; Ananthi, T; Anandkumar, B; Maruthamuthu, S

    2012-03-01

    In this study, Arthrobacter luteolus, isolated from rare earth environment of Chavara (Quilon district, Kerala, India), were found to produce catechol-type siderophores. The bacterial strain accumulated rare earth elements such as samarium and scandium. The siderophores may play a role in the accumulation of rare earth elements. Catecholate siderophore and low-molecular-weight organic acids were found to be present in experiments with Arthrobacter luteolus. The influence of siderophore on the accumulation of rare earth elements by bacteria has been extensively discussed.

  15. Synthesis of 2-(9,10-Dihydro-9,10-propanoanthracen-9-yl-N-methylethanamine via a [4+2] Cycloaddition

    Directory of Open Access Journals (Sweden)

    Usama Karama

    2010-06-01

    Full Text Available The synthesis of the tetracyclic molecule 2-(9,10-dihydro-9,10-propano-anthracen-9-yl-N-methylethanamine(2as a homologue of the antidepressant 1-(9,10-dihydro-9,10-ethanoanthracen-9-yl-N-methylmethaneamine (1 was described. The key intermediate 9-(prop-2-en-1-yl-9,10-dihydro-9,10-propanoanthracen-12-one (7was successfully synthesized via a [4+2] cycloaddition of α-bromoacrolein and 9-allyl-anthracene, followed by ring expansion and samarium diiodide deoxygenation.

  16. Synthesis of 2-(9,10-dihydro-9,10-propanoanthracen-9-yl)-N-methylethanaminevia a [4+2] cycloaddition.

    Science.gov (United States)

    Karama, Usama; Al-Saidey, Adel; Al-Othman, Zeid; Almansour, Abdel Rahman

    2010-06-09

    The synthesis of the tetracyclic molecule 2-(9,10-dihydro-9,10-propano-anthracen-9-yl)-N-methylethanamine (2) as a homologue of the antidepressant 1-(9,10-dihydro-9,10-ethanoanthracen-9-yl)-N-methylmethaneamine (1) was described. The key intermediate 9-(prop-2-en-1-yl)-9,10-dihydro-9,10-propanoanthracen-12-one (7) was successfully synthesized via a [4+2] cycloaddition of alpha-bromoacrolein and 9-allyl-anthracene, followed by ring expansion and samarium diiodide deoxygenation.

  17. SPECTROSCOPIC PROPERTIES OF THE Ln-Ge COMPLEXES WITH DIETHYLENETRIAMINEPENTAACETIC ACID

    Directory of Open Access Journals (Sweden)

    Sergiy Smola

    2007-06-01

    Full Text Available Four new heteronuclear lanthanide complexes with general formula [Ge(OH(μ-HDTPALnGe(OH (μ-DTPA] (Ln = Sm – Dy were synthesized and subsequently characterized by different physico- chemical methods. The structures of new compounds have been proposed. In considered complexes the 4f-luminescence of three-charged ions of samarium, europium, terbium and dysprosium is realized at UV-excitation. It is noteworthy that it is the first observation of 4f-luminescence in water solutions of heteronuclear f-p-complexes. The comparison of luminescent characteristics of hetero- and homonuclear landthanide complexes is described and discussed as well.

  18. Die selfverstaan van die Samaritane soos dit uit- drukking vind in die feesliturgie צלות מוצד השמיני

    Directory of Open Access Journals (Sweden)

    J. Beyers

    1999-01-01

    Full Text Available The self-understanding of the Samaritans, as expressed in the liturgy of the צלות מוצד השמיני festivalThis study is concerned with the identity and religion of the Samaritans. The way in which the Samaritans understood their identity is highlighted by their perception of God, by the traditions they adhered to and by the selection of texts from the Pentateuch they used in their liturgy. The beliefs and rituals of the Samarium faith found their way into the Samaritan Liturgy. The study of a part of the Samaritan Liturgy shows that the Samaritans are heirs to the religion of the northern tibes of Israel.

  19. Development of atomic spectroscopy technology -Development of ultrasensitive spectroscopic analysis technology

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Hyung Kee; Song Kyoo Suk; Kim, Duk Hyun; Hong, Suk Kyung; Lee, Yong Joo; Lee, Jong Hoon; Yang, Kee Hoh [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-07-01

    For the resonance ionization spectroscopy experiment, erbium and samarium were chosen as test elements and their optimum photoionization schemes for trace analysis have been investigated by using multiphoton spectroscopic techniques. With the optimum scheme, the detection limit of various atoms were measured. For the test of laser induced fluorescence system, calibration curves obtained from lead and cadmium standard solutions were made and Pb concentrations of various unknown solutions were determined. By using the developed differential absorption lidar system, backscattering signals from aerosol and ozone have been measured. Error source, error calibration and data interpretation techniques have been also studied. 60 figs, 8 pix, 28 tabs, 30 refs. (Author).

  20. Detection of rare earth elements in Powder River Basin sub-bituminous coal ash using laser-induced breakdown spectroscopy (LIBS)

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Phuoc [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United State; Mcintyre, Dustin [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United State

    2015-10-01

    We reported our preliminary results on the use of laser-induced breakdown spectroscopy to analyze the rare earth elements contained in ash samples from Powder River Basin sub-bituminous coal (PRB-coal). We have identified many elements in the lanthanide series (cerium, europium, holmium, lanthanum, lutetium, praseodymium, promethium, samarium, terbium, ytterbium) and some elements in the actinide series (actinium, thorium, uranium, plutonium, berkelium, californium) in the ash samples. In addition, various metals were also seen to present in the ash samples

  1. Giant magneto resistance and temperature coefficient of resistance in Sm0.55Sr0.30Ag0.15MnO3 perovskite

    OpenAIRE

    Bhat, Masroor Ahmad; Zargar, Rayees A.; Modi, Anchit; Arora, Manju; Gaur, N K

    2016-01-01

    Silver ions substituted samarium strontium manganite (Sm0.55Sr0.30Ag0.15MnO3) pervoskite was synthesized by using respective oxides in stoichiometric ratio through solid state reaction. The as-prepared sample was characterized by various analytical techniques to confirm its formation and understand the effect of monovalent silver ions in pervoskite lattice. X-ray diffraction pattern confirms the single phase formation while grain morphology in SEM image indicates good connectivity among the g...

  2. Boronization and Carburization of Superplastic Stainless Steel and Titanium-Based Alloys

    Directory of Open Access Journals (Sweden)

    Masafumi Matsushita

    2011-07-01

    Full Text Available Bronization and carburization of fine-grain superplastic stainless steel is reviewed, and new experimental results for fine grain Ti88.5Al4.5V3Fe2Mo2 are reported. In superplastic duplex stainless steel, the diffusion of carbon and boron is faster than in non-superplastic duplex stainless steel. Further, diffusion is activated by uniaxial compressive stress. Moreover, non-superplastic duplex stainless steel shows typical grain boundary diffusion; however, inner grain diffusion is confirmed in superplastic stainless steel. The presence of Fe and Cr carbides or borides is confirmed by X-ray diffraction, which indicates that the diffused carbon and boron react with the Fe and Cr in superplastic stainless steel. The Vickers hardness of the carburized and boronized layers is similar to that achieved with other surface treatments such as electro-deposition. Diffusion of boron into the superplastic Ti88.5Al4.5V3Fe2Mo2 alloy was investigated. The hardness of the surface exposed to boron powder can be increased by annealing above the superplastic temperature. However, the Vickers hardness is lower than that of Ti boride.

  3. Scoping corrosion tests on candidate waste package basket materials for the Yucca Mountain Project

    Energy Technology Data Exchange (ETDEWEB)

    Van Konynenburg, R.A.; Curits, P.C.; Summers, T.S.E.

    1998-03-01

    A scoping corrosion test was performed on candidate waste package basket materials. The corrosion medium was a pH-buffered solution of chemical species expected to be produced by radiolysis. The test was conducted at 90{degrees}C for 96 hours. Samples included aluminum-, copper-, stainless steel-, and zirconium-based metallic materials and several ceramics, incorporating neutron-absorbing elements. Sample weight losses and solution chemical changes were measured. Both corrosion of the host materials and dissolution of the neutron- absorbing elements were studied. The ceramics and the zirconium-based materials underwent only minor corrosion. the stainless steel-based materials performed well except for a welded sample. The aluminum- and copper-based materials exhibited the highest corrosion rates. Boron dissolution depends on it chemical form. Boron oxide and many metal borides dissolve readily in acidic solutions while high- chromium borides and boron carbide, though thermodynamically unstable, exhibit little dissolution in short times. the results of solution chemical analyses were consistent with this. Gadolinium did not dissolve significantly from monazite, and hafnium showed little dissolution from a variety of host materials, in keeping with its low solubility.

  4. Thermoelectric Properties and Band Structure Calculations of Novel Boron Network Compounds

    Science.gov (United States)

    Mori, Takao; Nishimura, Toshiyuki; Grin, Yuri; Shishido, Toetsu; Nakajima, Kazuo

    2009-03-01

    Boron is an interesting element, tending to form atomic networks such as 2D atomic nets and clusters, with some analogy to carbon systems which have been more extensively studied. Boron has one less electron than carbon and thus is electron deficient when forming atomic networks, but this causes it to have a special affinity with the rare earth elements and as a result, many new compounds have recently been discovered [1]. Their potential as viable thermoelectric materials is attracting interest since they are high-temperature materials and possess intrinsic low thermal conductivity, with some compounds exhibiting Seebeck coefficients in excess of 200 μV/K above 1000 K. The thermoelectric properties and band structure calculations of novel borides such as RB44Si2, RB17CN, RB22C2N, RB28.5C4 will be presented. Features in the band structure near the Fermi level indicate large doping effects in these compounds. Various doping experiments were carried out resulting in large increases to the figure of merit. [1] T. Mori, ``Higher Borides,'' in: Handbook on the Physics and Chemistry of Rare Earths, Vol. 38, (North-Holland, Amsterdam, 2008) p. 105-173.

  5. Microstructural Evolution of (Ti,W,CrB2 Coatings Deposited on Steel Substrates during Annealing

    Directory of Open Access Journals (Sweden)

    Aleksandra Newirkowez

    2014-05-01

    Full Text Available The topic of the present experiments are transition metal diboride coatings of composition (Ti0.49W0.51B2 and (Ti0.44W0.30Cr0.26B2. The coatings were deposited on steel substrates using dc magnetron sputtering. We investigated how annealing in argon at elevated temperatures modifies microstructure. The as-deposited films are amorphous. Annealing between 700 and 1100 °C results in the formation of nano-crystalline precipitates with average grain diameters of about 10–50 nm. A TiC phase (Fm-3m; a ≈ 4.3 Å is observed as the dominating precipitate phase. In addition, small amounts (10%–20% of a Cr23C6 phase (Fm-3m; a ≈ 10.6 Å are observed. In contrast to literature data on the same coatings deposited on silicon substrates, the formation of boride precipitate phases is strongly suppressed here. From investigations with X-ray diffractometry, electron microscopy and secondary ion mass spectrometry we conclude that the nanostructure of the coatings is formed by reactive phase formation of the boride coating with the carbon containing steel substrate.

  6. Stabilization of LnB12 (Ln = Gd, Sm, Nd, and Pr) in Zr1-xLnxB12 under Ambient Pressure.

    Science.gov (United States)

    Akopov, Georgiy; Sobell, Zachary C; Yeung, Michael T; Kaner, Richard B

    2016-12-05

    We report ambient pressure stabilization of a previously synthesized high-pressure (6.5 GPa) phase, GdB12, in a Zr1-xGdxB12 solid solution (with ∼54 at. % Gd solubility, as determined by both powder X-ray diffraction and energy-dispersive spectroscopy). Limited solubilities of Sm (∼15 at. % Sm), Nd (∼7 at. % Nd), and Pr (∼4 at. % Pr), in ZrB12 were also achieved. Previous attempts at preparing these rare-earth borides were unsuccessful even under high pressure. On the basis of insights provided from the unit cell sizes observed via solid solutions, at least 6.5 GPa of pressure would be needed to synthesize these rare-earth borides since Sm, Nd, and Pr atomic radii are larger than that of Gd. The solid-solution formation for Zr1-xGdxB12 and Zr1-xSmxB12 can be seen in the change of the unit cell of each of the solid solutions relative to their pure parent compounds as well as in the change of color of the respective alloys. For Zr0.45Gd0.55B12 and Zr0.70Sm0.30B12, the cubic unit cell parameter (a) reached a value of 7.453 and 7.428 Å, respectively, compared to 7.412 Å for pure ZrB12.

  7. Microstructural analyses of B{sub 4}C-CeO{sub 2} and B{sub 4}C-La{sub 2}O{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Tatsuaki, E-mail: sakamoto.tatsuaki@eng.ehime-u.ac.jp [Department of Materials Science and Biotechnology, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Sun, Shu-Chen [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Furuno, Tomoya; Kajioka, Michio [Graduate Student of Ehime Univerisity, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Nakai, Kiyomichi [Department of Materials Science and Biotechnology, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Kurishita, Hiroaki [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Kobayashi, Sengo [Department of Materials Science and Biotechnology, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Wu, Wen-Yuan; Tu, Gan-Feng [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Matsuda, Seiji [Department of Anatomy and Embryology, Ehime University, Shizugawa, Toon 791-0295 (Japan)

    2011-10-01

    Effects of additions of CeO{sub 2} and La{sub 2}O{sub 3} on microstructure and mechanical properties of B{sub 4}C fabricated under and without hot press have been investigated. Vickers hardness and fracture strength are increased by hot press due to the reduction of porosity because the sintering rate is enhanced. Hardness is increased by the reduction of porosity because crack probably occurs when the hardness is measured due to pore as an initiation point of crack. Hardness increases with increasing additions of CeO{sub 2} and La{sub 2}O{sub 3} because porosity decreases due to the formation of CeB{sub 6} and LaB{sub 6} on the grain boundary of B{sub 4}C, respectively. The borides are formed through reaction between solid phases, which might induce coherent boundary between boride and B{sub 4}C. Such coherency also contributes to strengthening the grain boundary of B{sub 4}C. The addition of CeO{sub 2} enhances the sintering rate more than that of La{sub 2}O{sub 3}, resulting in higher hardness of B{sub 4}C-CeO{sub 2} than that of B{sub 4}C-La{sub 2}O{sub 3}.

  8. High temperature thermoelectric energy conversion

    Science.gov (United States)

    Wood, Charles

    1987-01-01

    The theory and current status of materials research for high-temperature thermoelectric energy conversion are reviewed. Semiconductors are shown to be the preferred class of materials for this application. Optimization of the figure of merit of both broadband and narrow-band semiconductors is discussed as a function of temperature. Phonon scattering mechanisms are discussed, and basic material guidelines are given for reduction of thermal conductivity. Two general classes of materials show promise for high temperature figure of merit (Z) values, namely the rare earth chalcogenides and the boron-rich borides. The electronic transport properties of the rare earth chalcogenides are explicable on the basis of degenerate or partially degenerate n-type semiconductors. Boron and boron-rich borides exhibit p-type hopping conductivity, with detailed explanations proposed for the transport differing from compound to compound. Some discussion is presented on the reasons for the low thermal conductivities in these materials. Also, ZTs greater than one appear to have been realized at high temperature in many of these compounds.

  9. Effect of post-boronizing heat treatment on wear behaviour and pit formation in AISI-8620 gear steel

    Energy Technology Data Exchange (ETDEWEB)

    Aydin, H.; Sevim, V.; Demirci, A.H. [Uludag Univ., Gorukle-Bursa (Turkey)

    2007-07-01

    In this study the effect of post-boronizing heat treatment on wear behaviour and pit formation on a starter motor pinion gear, made from AISI-8620 steel, was investigated. This involved using a rotary wear test, where the number of cycles at a fixed load and a fixed rotational speed were varied. Boronizing was performed on starter motor pinion gears (test specimens) in a solid medium consisting of B{sub 4}C, SiC, KBF{sub 4} at a temperature of 900 C for 4 h. Following boronizing, test specimens were quenched in water at room temperature from the boronizing temperature and were subsequently tempered at 180 C for 1, 2 and 3 hours. As part of this investigation, microstructure and microhardness distribution of the boride layer and wear resistance and pitting damage rate of the specimens were examined for each of the tempering heat treatments. Morphology of the boride layer and pit formation were characterized using optical microscopy. Wear and pitting evaluations were carried out using a wear test apparatus made for this purpose, which simulates the pinion and flywheel starter ring gear pair. For each wear test the number of cycles was 25 x 10{sup 5}, inspected at 5 x 10{sup 5}-cycle intervals. It was concluded from these examinations that tempering heat treatments following boronizing contribute to the increase of microhardness alongside the surface layer, as well as an increase in wear resistance and pitting damage. (orig.)

  10. Microwave method for synthesis of micro- and nanostructures with controllable composition during gyrotron discharge

    Science.gov (United States)

    Batanov, German M.; Borzosekov, Valentin D.; Golberg, Dmitri; Iskhakova, Ludmila D.; Kolik, Leonid V.; Konchekov, Evgeny M.; Kharchev, Nikolai K.; Letunov, Alexander A.; Malakhov, Dmitry V.; Milovich, Filipp O.; Obraztsova, Ekaterina A.; Petrov, Alexander E.; Ryabikina, Irina G.; Sarksian, Karen A.; Stepakhin, Vladimir D.; Skvortsova, Nina N.

    2016-01-01

    We introduce an approach toward the synthesis of micro- and nanostructures under nonequilibrium microwave discharges within metal-dielectric powder mixtures induced by powerful microwave gyrotron radiation. A new plasma-chemical reactor capable of sustaining a discharge regime with an afterglow phase of an order of magnitude longer than the gyrotron pulse duration was constructed for these experiments. In the nonequilibrium conditions of such a discharge, plasma-induced exothermic chemical reactions leading to the synthesis of various compounds were initiated. The synthesized structures were deposited on the reactor walls and on the impurity particles within the reactor. This method was tested under gyrotron-initiated discharges within various metal-dielectric powder mixtures of titanium-boron, molybdenum-boron, titanium-silicon-boron, molybdenum-boron nitride, molybdenum-tungsten-boron nitride, and so on. Depending on the powder mixture composition, reactor atmosphere, and other parameters, micro- and nanosized particles of boron nitride, titanium diboride, molybdenum boride, titanium boride, molybdenum, and molybdenum oxide, were synthesized, detected, and analyzed.

  11. Thermal and stress studies of normal incidence Mo/B4C multilayers for a 6.7 nm wavelength.

    Science.gov (United States)

    Barthelmess, Miriam; Bajt, Saša

    2011-04-10

    Wavelength, reflectance, and stress stability of Mo/B(4)C multilayers were studied as a function of postdeposition annealing up to 900 °C. These multilayers are of interest as normal incidence coatings for wavelengths above the boron K-absorption edge. Mo/B(4)C multilayers deposited at low sputtering pressure have high compressive stress. Zero stress can be achieved at 360 °C-370 °C, but annealing at molybdenum and boron carbide layers separated by amorphous layers of molybdenum borides (Mo(x)B(y)) is presented. These interlayers are present already in the as-deposited state and continue to grow with increasing temperature. Their presence lowers the optical contrast and the achievable reflectivity. However, they also increase multilayer thermal stability. At temperatures >600 °C, a noticeable decrease in reflectivity associated with the phase transition from amorphous to crystalline molybdenum boride is observed. This is accompanied with an increase in interface and surface roughness and a change in stress as a function of temperature. © 2011 Optical Society of America

  12. Thermal and stress studies of normal incidence Mo/B{sub 4}C multilayers for a 6.7 nm wavelength

    Energy Technology Data Exchange (ETDEWEB)

    Barthelmess, Miriam; Bajt, Sasa

    2011-04-10

    Wavelength, reflectance, and stress stability of Mo/B{sub 4}C multilayers were studied as a function of postdeposition annealing up to 900 deg. C. These multilayers are of interest as normal incidence coatings for wavelengths above the boron K-absorption edge. Mo/B{sub 4}C multilayers deposited at low sputtering pressure have high compressive stress. Zero stress can be achieved at 360 deg. C-370 deg. C, but annealing at <200 deg. C is sufficient to reduce stress by {approx}40%. This stress relaxation is accompanied with a multilayer period expansion of {approx}0.02 nm and a <0.5% decrease in normal incidence reflectivity. The multilayer period remains stable up to {approx}600 deg. C, while intrinsic stress changes from compressive to tensile. A four-layer model with amorphous molybdenum and boron carbide layers separated by amorphous layers of molybdenum borides (Mo{sub x}B{sub y}) is presented. These interlayers are present already in the as-deposited state and continue to grow with increasing temperature. Their presence lowers the optical contrast and the achievable reflectivity. However, they also increase multilayer thermal stability. At temperatures >600 deg. C, a noticeable decrease in reflectivity associated with the phase transition from amorphous to crystalline molybdenum boride is observed. This is accompanied with an increase in interface and surface roughness and a change in stress as a function of temperature.

  13. Boronization and Carburization of Superplastic Stainless Steel and Titanium-Based Alloys.

    Science.gov (United States)

    Matsushita, Masafumi

    2011-07-18

    Bronization and carburization of fine-grain superplastic stainless steel is reviewed, and new experimental results for fine grain Ti88.5Al4.5V₃Fe₂Mo₂ are reported. In superplastic duplex stainless steel, the diffusion of carbon and boron is faster than in non-superplastic duplex stainless steel. Further, diffusion is activated by uniaxial compressive stress. Moreover, non-superplastic duplex stainless steel shows typical grain boundary diffusion; however, inner grain diffusion is confirmed in superplastic stainless steel. The presence of Fe and Cr carbides or borides is confirmed by X-ray diffraction, which indicates that the diffused carbon and boron react with the Fe and Cr in superplastic stainless steel. The Vickers hardness of the carburized and boronized layers is similar to that achieved with other surface treatments such as electro-deposition. Diffusion of boron into the superplastic Ti88.5Al4.5V₃Fe₂Mo₂ alloy was investigated. The hardness of the surface exposed to boron powder can be increased by annealing above the superplastic temperature. However, the Vickers hardness is lower than that of Ti boride.

  14. Tribological Properties of Surface Layer with Boron in Friction Pairs

    Science.gov (United States)

    Lubas, Janusz

    The aim of the present work is to determine the influence of technologically produced boron surface layers on the friction parameters in the sliding pairs under the conditions of mixed friction. The tribological evaluation included ion nitrided, pack borided, laser borided, quenched and tempered surface layers and TiB2 coating deposited on 38CrAlMo5-10, 46Cr2 and 30MnB4 steels. Modified surface layers of annular samples were matched under test conditions with counter-sample made from AlSn20 bearing alloy. Tested sliding pairs were lubricated with 15 W/40 Lotos mineral engine oil. The tribological tests were conducted on a T-05 block on ring tester. The applied steel surface layer modification with boron allows surface layers to be created with pre-determined tribological characteristics required for the elements of kinematic pairs operating in the conditions of sliding friction. Pack boronizing reduces the friction coefficient during the start-up of the frictional pair and the maximum start-up resistance level is similar to the levels of pairs with nitrided surface layers.

  15. Synergistic Effects of Sm and C Co-Doped Mixed Phase Crystalline TiO₂ for Visible Light Photocatalytic Activity.

    Science.gov (United States)

    Peng, Fuchang; Gao, Honglin; Zhang, Genlin; Zhu, Zhongqi; Zhang, Jin; Liu, Qingju

    2017-02-21

    Mixed phase TiO₂ nanoparticles with element doping by Sm and C were prepared via a facile sol-gel procedure. The UV-Vis light-diffuse reflectance spectroscopy analysis showed that the absorption region of co-doped TiO₂ was shifted to the visible-light region, which was attributed to incorporation of samarium and carbon into the TiO₂ lattice during high-temperature reaction. Samarium effectively decreased the anatase-rutile phase transformation. The grain size can be controlled by Sm doping to achieve a large specific surface area useful for the enhancement of photocatalytic activity. The photocatalytic activities under visible light irradiation were evaluated by photocatalytic degradation of methylene blue (MB). The degradation rate of MB over the Sm-C co-doped TiO₂ sample was the best. Additionally, first-order apparent rate constants increased by about 4.3 times compared to that of commercial Degusssa P25 under the same experimental conditions. Using different types of scavengers, the results indicated that the electrons, holes, and •OH radicals are the main active species for the MB degradation. The high visible-light photocatalytic activity was attributed to low recombination of the photo-generated electrons and holes which originated from the synergistic effect of the co-doped ions and the heterostructure.

  16. Molecular electrophosphorescence in (Sm, Gd)-{beta}-diketonate complex blend for OLED applications

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, R., E-mail: fisicaplic@hotmail.com [Facultad de Ingenieria Quimica y Textil, Universidad Nacional de Ingenieria, UNI, Av. Tupac Amaru 210, Lima 31, Peru (Peru); Cremona, M. [DIMAT - Divisao de Metrologia de Materiais, Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial, INMETRO, Duque de Caxias, RJ (Brazil); Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, PUC-Rio, C.P. 38071, Rio de Janeiro, RJ, CEP 22453-970 (Brazil); Teotonio, E.E.S. [Departamento de Quimica, CCEN, Universidade Federal da Paraiba, UFPB, C.P. 5093, Joao Pessoa, PB, CEP 5805-970 (Brazil); Brito, H.F. [Instituto de Quimica, Universidade de Sao Paulo, USP, C.P. 26077, Sao Paulo, SP, CEP 05599-970 (Brazil); Malta, O.L. [Departamento de Quimica Fundamental, CCEN, Universidade Federal de Pernambuco, Cidade Universitaria, Recife, PE, CEP 50670-901 (Brazil)

    2013-02-15

    In this work the preparation and characterization of the triple-layer organic light-emitting diode (OLED) using a mixture of the samarium and gadolinium {beta}-diketonate complexes [Sm{sub 0.5}Gd{sub 0.5}(TTA){sub 3}(TPPO){sub 2}] as emitting layer is reported. The OLED's devices contain 1-(3-methylphenyl)-1,2,3,4-tetrahydroquinoline-6-carboxyaldehyde-1, 1'-diphenylhydrazone (MTCD) as hole-transporting layer and tris(8-hydroxyquinoline aluminum) (Alq{sub 3}) as electron transporting layer. The electroluminescence spectrum present emission narrow bands from the {sup 4}G{sub 5/2}{yields}{sup 6}H{sub J} transitions (where J=5/2, 7/2 and 9/2) characteristic of the Sm{sup 3+} ion. These sharp lines are overlapped with a broad band attributed to the electrophosphorescence from the T{sub 1}{yields}S{sub 0} transition in the ligand TTA. The intramolecular energy transfer is discussed and applied on the change of the emission color of the organic LEDs at different bias voltages. - Highlights: Black-Right-Pointing-Pointer Samarium and gadolinium complexes. Black-Right-Pointing-Pointer OLED with complex blend (Sm,Gd). Black-Right-Pointing-Pointer Electrophosphorescence emission detection. Black-Right-Pointing-Pointer Application in OLED changing the color emission.

  17. Spontaneous and stimulated emission in Sm{sup 3+}-doped YAl{sub 3}(BO{sub 3}){sub 4} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Ryba-Romanowski, Witold [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland); Lisiecki, Radosław, E-mail: R.Lisiecki@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland); Beregi, Elena [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest (Hungary); Martín, I.R. [Departamento de Física, Instituto de Materiales y Nanotecnología (IMN), Universidad de La Laguna, 38206 S/C de Tenerife, Laguna (Spain)

    2015-11-15

    Single crystals of YAl{sub 3}(BO{sub 3}){sub 4} doped with trivalent samarium were grown by the top-seeded high temperature solution method and their absorption and emission spectra were investigated. Optical pumping into prominent absorption band around 405 nm feeds the {sup 4}G{sub 5/2} metastable level giving rise to intense visible luminescence distributed in several spectral lines with the most intense line around 600 nm characterized by a branching ratio of 0.42 and peak emission cross section of 0.25×10{sup −20} cm{sup 2}. Optical amplification at 600 nm with a gain coefficient of 2.9 cm{sup −1} was achieved during a pump-and-probe experiment. - Highlights: • YAB:Sm crystal grown by the top-seeded high temperature solution method. • Spectroscopic qualities relevant for visible laser operation. • YAB:Sm single crystal used in a pump-and-probe experiment. • Optical amplification properties of samarium doped YAl{sub 3}(BO{sub 3}){sub 4}.

  18. Synthesis of Sm2(WO4)3 nanocrystals via a statistically optimized route and their photocatalytic behavior

    Science.gov (United States)

    Mahdi Pourmortazavi, Seied; Rahimi-Nasrabadi, Mehdi; Aghazadeh, Mustafa; Ganjali, Mohammad Reza; Sadeghpour Karimi, Meisam; Norouzi, Parviz

    2017-03-01

    The application of a Taguchi approach to the optimization of the precipitation reaction between Sm3+ and {{{{WO}}}{{4}}}2- as a rapid procedure for the preparation of Sm2(WO4)3 nanoparticles as a photocatalyst is evaluated. The effect of the prominent operating factors on the product are evaluated so as to yield the best synthesis conditions, leading to the finest product particles of the desired morphologies, which can turn the rather primitive precipitation reaction into a powerful tool for the preparation of nanostructured crystals of insoluble salts. The effects of the alteration of the studied factors on the final properties of the product are further evaluated through characterization techniques, including x-ray diffraction, energy-dispersive x-ray analysis, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The results of the study, together with the analysis of variance operations, revealed that through the control of samarium and tungstate concentrations, and temperature, considerable results can be achieved in terms of the product dimensions, morphology, purity and structure. Moreover, the photocatalytic behavior of the synthesized samarium tungstate nanoparticles for the photocatalytic degradation of methylene blue under ultraviolet light is investigated and compared with titanium dioxide as a well-known photocatalyst.

  19. High-pressure synthesis and exotic heavy-fermion behaviour of the filled skutterudite SmPt{sub 4}Ge{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Gumeniuk, R; Leithe-Jasper, A; Schnelle, W; Nicklas, M; Rosner, H; Ormeci, A; Burkhardt, U; Schmidt, M; Schwarz, U; Grin, Yu [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, 01187 Dresden (Germany); Schoeneich, M; Ruck, M, E-mail: schnelle@cpfs.mpg.d [Anorganische Chemie, Technische Universitaet Dresden, 01062 Dresden (Germany)

    2010-10-15

    Ternary samarium-filled platinum-germanium skutterudite SmPt{sub 4}Ge{sub 12} was prepared at a pressure of 5.0(0.5) GPa and a temperature of 1070(70) K. The compound crystallizes in the cubic space group Im 3-bar (a=8.6069(4) A) and is isotypic with LaFe{sub 4}P{sub 12}. X-ray absorption spectroscopy measurements show that samarium in SmPt{sub 4}Ge{sub 12} has a temperature-independent intermediate valence ({nu}=2.90{+-}0.03). Magnetization data reveal Van Vleck paramagnetism above {approx}50 K. The low-temperature specific heat displays a broad anomaly centred at 2.9 K and a large linear coefficient {gamma} ' =450 mJ mol{sup -1} K{sup -2} suggesting heavy-fermion behaviour. Low-temperature electrical resistivity shows a temperature dependence reminiscent of the Kondo effect. Density functional calculations result in an electronic structure that is, apart from the Sm 4f contributions, very similar to LaPt{sub 4}Ge{sub 12}.

  20. Ni-Zn-Sm nanopowder ferrites: Morphological aspects and magnetic properties

    Science.gov (United States)

    Costa, A. C. F. M.; Diniz, A. P. A.; de Melo, A. G. B.; Kiminami, R. H. G. A.; Cornejo, D. R.; Costa, A. A.; Gama, L.

    Ni-Zn ferrites have been widely used in components for high-frequency range applications due to their high electrical resistivity, mechanical strength and chemical stability. Ni-Zn ferrite nanopowders doped with samarium with a nominal composition of Ni 0.5Zn 0.5Fe 2-xSm xO 4 ( x=0.0, 0.05, and 0.1 mol) were obtained by combustion synthesis using nitrates and urea as fuel. The morphological aspects of Ni-Zn-Sm ferrite nanopowders were investigated by X-ray diffraction, nitrogen adsorption by BET, sedimentation, scanning electron microscopy and magnetic properties. The results indicated that the Ni-Zn-Sm ferrite nanopowders were composed of soft agglomerates of nanoparticles with a high surface area (55.8-64.8 m 2/g), smaller particles (18-20 nm) and nanocrystallite size particles. The addition of samarium resulted in a reduction of all the magnetic parameters evaluated, namely saturation magnetization (24-40 emu/g), remanent magnetization (2.2-3.5 emu/g) and coercive force (99.3-83.3 Oe).

  1. Magnetic and magnetoelastic properties of epitaxial SmFe{sub 2} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Fuente, C de la; Arnaudas, J I; Ciria, M; Del Moral, A [Departamento de Magnetismo de Solidos and Departamento de Fisica de la Materia Condensada, Instituto de Ciencia de los Materiales de Aragon and Universidad de Zaragoza, 50071, Zaragoza (Spain); Dufour, C; Dumesnil, K, E-mail: cesar@unizar.e [Laboratoire de Metallurgie Physique et de Science des Materiaux, Universite Henry Poincare, Nancy 1, BP 239, 54506 (France)

    2010-02-03

    We report on magnetic and magnetoelastic measurements for a 5000 A (110) SmFe{sub 2} thin film, which was successfully analyzed by means of a point charge model for describing the effect of the epitaxial growth in this kind of system. Some of the main conclusions of the Moessbauer and magnetoelastic results and the new magnetization results up to 5 T allow us to get a full description of the crystal electric field, exchange, and magnetoelastic behavior in this compound. So, new single-ion parameters are obtained for the crystal field interaction of samarium ions, A{sub 4}(r{sup 4}) = +755 K/ion and A{sub 6}(r{sup 6}) = -180 K/ion, and new single-ion magnetoelastic coupling B{sup gamma}{sup ,2}approx =-200 MPa and B{sup epsilon}{sup ,2}approx =800 MPa, which represent the tetragonal and the in-plane shear deformations, respectively. Moreover, the new thermal behavior of the samarium magnetic moment, the exchange coupling parameter, and the magnetocrystalline anisotropy of the iron sublattice are obtained too. From these, the softening of the spin reorientation transition with respect to the bulk case could be accounted for.

  2. Synergistic Effects of Sm and C Co-Doped Mixed Phase Crystalline TiO2 for Visible Light Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Fuchang Peng

    2017-02-01

    Full Text Available Mixed phase TiO2 nanoparticles with element doping by Sm and C were prepared via a facile sol-gel procedure. The UV-Vis light-diffuse reflectance spectroscopy analysis showed that the absorption region of co-doped TiO2 was shifted to the visible-light region, which was attributed to incorporation of samarium and carbon into the TiO2 lattice during high-temperature reaction. Samarium effectively decreased the anatase-rutile phase transformation. The grain size can be controlled by Sm doping to achieve a large specific surface area useful for the enhancement of photocatalytic activity. The photocatalytic activities under visible light irradiation were evaluated by photocatalytic degradation of methylene blue (MB. The degradation rate of MB over the Sm-C co-doped TiO2 sample was the best. Additionally, first-order apparent rate constants increased by about 4.3 times compared to that of commercial Degusssa P25 under the same experimental conditions. Using different types of scavengers, the results indicated that the electrons, holes, and •OH radicals are the main active species for the MB degradation. The high visible-light photocatalytic activity was attributed to low recombination of the photo-generated electrons and holes which originated from the synergistic effect of the co-doped ions and the heterostructure.

  3. Viability of biocompatible and biodegradable seeds production with incorporated radionuclides; Viabilidade da producao de sementes biocompativeis e biodegradaveis com radionuclideos incorporados

    Energy Technology Data Exchange (ETDEWEB)

    Roberto, W.S. [Centro Federal de Educacao Tecnologica de Ouro Preto (CEFET/OP), MG (Brazil); Pereira, M.M.; Vasconcelos, W.L.; Campos, T.P.R. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)], e-mail: wanderley@nuclear.ufmg.br

    2000-07-01

    The present work aims the development of radioactive seeds, biocompatible and biodegradable, with the objective of adding options in the cancer treatment. The work focus on the production of seeds biodegradable that incorporate radioisotopes with half life inferior than the degradation time of the material. The idea of producing devices with biodegradable materials impregnated with radioisotopes of short half life will offer new possibilities in the cancer treatment, since they can be used following the same procedures of the permanent interstitial brachytherapy, but using degradable materials compatible with the physiological environment. It will be discussed in particular the possible application of these seeds in the treatment of prostate cancer. A review of the subject and a preliminary evaluation of the viability of production of the seeds will be presented. The method of production of the seeds is based on the incorporation of Iodine and Samarium in glass matrixes obtained by sol-gel processing. X-ray fluorescence was done in the samples produced and the incorporation of Iodine and Samarium atoms was confirmed. (author)

  4. Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets.

    Science.gov (United States)

    Imashuku, Susumu; Wagatsuma, Kazuaki; Kawai, Jun

    2016-02-01

    Scanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium-iron-boron (NdFeB) and samarium-cobalt (Sm-Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm-Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.

  5. Uptake and effect of rare earth elements on gene expression in Methylosinus trichosporium OB3b.

    Science.gov (United States)

    Gu, Wenyu; Farhan Ul Haque, Muhammad; DiSpirito, Alan A; Semrau, Jeremy D

    2016-07-01

    It is well known that Methylosinus trichosporium OB3b has two forms of methane monooxygenase (MMO) responsible for the initial conversion of methane to methanol, a cytoplasmic (soluble) methane monooxygenase and a membrane-associated (particulate) methane monooxygenase, and that copper strongly regulates expression of these alternative forms of MMO. More recently, it has been discovered that M. trichosporium OB3b has multiple types of the methanol dehydrogenase (MeDH), i.e. the Mxa-type MeDH (Mxa-MeDH) and Xox-type MeDH (Xox-MeDH), and the expression of these two forms is regulated by the availability of the rare earth element (REE), cerium. Here, we extend these studies and show that lanthanum, praseodymium, neodymium and samarium also regulate expression of alternative forms of MeDH. The effect of these REEs on MeDH expression, however, was only observed in the absence of copper. Further, a mutant of M. trichosporium OB3b, where the Mxa-MeDH was knocked out, was able to grow in the presence of lanthanum, praseodymium and neodymium, but was not able to grow in the presence of samarium. Collectively, these data suggest that multiple levels of gene regulation by metals exist in M. trichosporium OB3b, but that copper overrides the effect of other metals by an as yet unknown mechanism. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Threshold sensitivity of quartz variometers with negative feedback

    Science.gov (United States)

    Odintsov, V. I.; Petrov, V. G.

    2017-05-01

    The maximum achievable parameters of magnetometers based on optomechanical quartz variometers are studied in connection with the planned transition of the international network Intermagnet to 1-s recording and the need to provide the network of Russian geomagnetic observatories with domestic magnetometers that satisfy Intermagnet requirements. The mechanism of negative feedback effect on the sensitivity threshold of a variometer with an optoelectronic angle transducer is shown. The optimization criterion for the size and shape of the magnets made of different magnetic materials is defined by the maximum ratio of the magnetic moment to the inertial moment. Theoretical and experimental evaluation of the variometer noise level is based on vicalloy and samarium-cobalt. It is shown that the frequency range of magnetometers with variometers based on vicalloy and samarium-cobalt will be bounded from above by frequencies of 1.6 and 6.4 Hz, respectively, at a threshold sensitivity of about 1 pT. These ratios of the frequency and threshold sensitivity for the given magnetic materials are probably limited for quartz variometers with an optoelectronic angle transducer.

  7. Measurement of solubility of plutonium trifluoride and rare-earth fluorides in molten LiF-BeF{sub 2}-ZrF{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Naumov, V.S.; Bychkov, A.V.; Kormilitsyn, M.V. [and others

    1996-12-01

    Data on behavior of plutonium fluoride and fission products (FP) dissolved in fuel composition are needed to calculate the duration of an operating cycle of the ADTT facility (Accelerator-Driver Transmutation Technologies) and to determine the effect of their equilibrium concentrations on nuclear-physical characteristics of reactor operation. The data on the FP fluoride solubility in the molten salts are of great important for some industrial processes (electrolytical metal deposition, development of physical-chemical mean for processes of chemical technology, etc.) As noted above, some information on this question is given in monography and articles. Data concerning fluoride salts are given in reports. However, it was impossible to make the substantial analysis of mutual solubility of fluoride melts. The primary investigation of CeF{sub 3} and neodymium, samarium and lanthanum fluorides showed that the solubility of the melt LiF-BeF{sub 2} and LiF-BeF{sub 2}-ThF{sub 4} was a linear function of reverse temperature and increases from lanthanum to samarium in the row of rare-earth elements. Disagreement in estimation of plutonium trifluoride solubility and incomplete data on the solubility of rare-earth elements prompted this study.

  8. Determination of the Speciation and Bioavailability of Sm to Chlamydomonas reinhardtii in the Presence of Natural Organic Matter.

    Science.gov (United States)

    Rowell, Justine-Anne; Fillion, Marc-Alexandre; Smith, Scott; Wilkinson, Kevin J

    2018-02-03

    As technological interest and environmental emissions of the rare earth elements (REE) increase, it is becoming more important to assess their potential environmental impact. Samarium (Sm) is a lanthanide of intermediate molar mass that is used in numerous high technology applications including wind turbines, solar panels and electric vehicles. The present study relates the speciation of samarium (Sm) determined in the presence of natural organic matter (NOM) to its bioavailability to the unicellular green alga, Chlamydomonas reinhardtii. The free ion concentration was determined using a cation exchange resin (IET) in dynamic mode and compared to thermodynamic modelling. Short-term biouptake experiments were performed in the presence of 4 types of NOM: Suwannee River fulvic acids, Pahokee Peat fulvic acids, Suwannee River humic acids and a Luther Marsh dissolved organic matter isolate (90-95% humic acids). The results clearly showed that even a small amount of NOM (0.5 mg C L-1 ) resulted in a significant decrease (10x) in the Sm internalization fluxes. Furthermore, complexation with humic acids (and the corresponding reduction in Sm bioavailability) was stronger than for the fulvic acids. The results showed that the experimentally measured (free) Sm was a better predictor of Sm internalization than either the total concentrations or the free ion concentrations obtained using thermodynamic modelling. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  9. Improved transistor-controlled and commutated brushless DC motors for electric vehicle propulsion

    Science.gov (United States)

    Demerdash, N. A.; Miller, R. H.; Nehl, T. W.; Nyamusa, T. A.

    1983-01-01

    The development, design, construction, and testing processes of two electronically (transistor) controlled and commutated permanent magnet brushless dc machine systems, for propulsion of electric vehicles are detailed. One machine system was designed and constructed using samarium cobalt for permanent magnets, which supply the rotor (field) excitation. Meanwhile, the other machine system was designed and constructed with strontium ferrite permanent magnets as the source of rotor (field) excitation. These machine systems were designed for continuous rated power output of 15 hp (11.2 kw), and a peak one minute rated power output of 35 hp (26.1 kw). Both power ratings are for a rated voltage of 115 volts dc, assuming a voltage drop in the source (battery) of about 5 volts. That is, an internal source voltage of 120 volts dc. Machine-power conditioner system computer-aided simulations were used extensively in the design process. These simulations relied heavily on the magnetic field analysis in these machines using the method of finite elements, as well as methods of modeling of the machine power conditioner system dynamic interaction. These simulation processes are detailed. Testing revealed that typical machine system efficiencies at 15 hp (11.2 kw) were about 88% and 84% for the samarium cobalt and strontium ferrite based machine systems, respectively. Both systems met the peak one minute rating of 35 hp.

  10. Study of rare earth separation by counter current electromigration; Estudo da separacao de terras raras por eletromigracao em contra corrente

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Sergio Machado

    1995-08-01

    The counter current electromigration (CCEM) is an electrophoretic technique where the charged species migrate on an electrical field toward an electrolytic flux. Usually this electrolyte is a complexing agent and is necessary to increase the small differences between the species mobilities. A new column was developed, all made of acrylic, in a cylindrical shape. A set of experiments was carried out with the species Na{sup +}/K{sup +}, K{sup +}/Sm{sup +3}, K{sup +}/Eu{sup +3} and K{sup +}/Sm{sup +3}/Eu{sup +3} using the {alpha}-hydrox i-isobutyric acid o,01 M as the counter current electrolytic flux. From a synthetic mixture of 90% of samarium and 10% of europium was obtained the samarium ion in a purity better than 99,9% where the concentration of Eu was determined by the polarography technique. The potassium ion was used as a leading electrolyte. It was also measured the mobilities of the involved species in the {alpha}-HIBA medium. Two models are proposed, a stationary model and a dynamic one. A simulator of a simplified stationary model, prepared in FORTRAN language, was developed and tested toward experimental results. (author)

  11. OXIDATIVE DEHYDROGENATION OF PROPANE BY RARE EARTH PHOSPHATES SUPPORTED ON AL-PILC

    Directory of Open Access Journals (Sweden)

    Carolina De Los Santos

    2012-12-01

    Full Text Available Catalytic activity in propane oxidative dehydrogenation of rare earth phosphates LnPO4 (where Ln = La, Ce, Pr, Nd, Sm and of the same supported by an aluminum pillared clay, of high specific surface area, is presented. The solids were characterized by TGA, XRD, nitrogen adsorption and immediate analysis after reaction in order to determine eventual carbon formation. Catalytic assays were performed at temperatures in the range 400oC-600oC, the reaction mixture was C3H8/O2/Ar = 10/10/80. All the catalysts were active. The reaction products were H2, CO, CO2, CH4, C2H4 and C3H6 and there were no organic oxygenated compounds detected. Although all the investigated systems were active, the Al-PILC supported catalysts presented a higher activity than the bulk materials. In this context, the samarium supported catalyst showed a propene yield increase from 4% to 10% compared with bulk samarium phosphate at 600°C. This effect was attributed to the increase in the specific surface area.

  12. Nb{sub 2}OsB{sub 2}, with a new twofold superstructure of the U{sub 3}Si{sub 2} type: Synthesis, crystal chemistry and chemical bonding

    Energy Technology Data Exchange (ETDEWEB)

    Mbarki, Mohammed; Touzani, Rachid St.; Fokwa, Boniface P.T., E-mail: boniface.fokwa@ac.rwth-aachen.de

    2013-07-15

    The new ternary metal-rich boride, Nb{sub 2}OsB{sub 2}, was synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere. The compound was characterized from single-crystal X-ray data and EDX measurements. It crystallizes as a new superstructure (space group P4/mnc, no. 128) of the tetragonal U{sub 3}Si{sub 2}-structure type with lattice parameters a=5.922(1) Å and c=6.879(2) Å. All of the B atoms are involved in B{sub 2} dumbbells with B–B distances of 1.89(4) Å. Structure relaxation using VASP (Vienna ab intio Simulation Package) has confirmed the space group and the lattice parameters. According to electronic structure calculations (TB–LMTO–ASA), the homoatomic B–B interactions are optimized and very strong, but relatively strong heteroatomic Os–B, Nb–B and Nb–Os bonds are also found: These interactions, which together build a three-dimensional network, are mainly responsible for the structural stability of this new phase. The density of state at the Fermi level predicts metallic behavior, as expected, from this metal-rich boride. - Graphical abstract: Nb{sub 2}OsB{sub 2} is, to the best of our knowledge, the first fully characterized phase in the ternary Nb–Os–B system. It crystallizes (space group P4/mnc, 128) with a new twofold superstructure of the U{sub 3}Si{sub 2} structure type (space group P4/mbm, 127), and is therefore the first boride in this structure family crystallizing with a superstructure of the U{sub 3}Si{sub 2} structure type. We show that the distortions leading to this superstructure occurs mainly in the Nb-layer, which tries to accommodate the large osmium atoms. The consequence of this puckering is the building osmium dumbbells instead of chains along [001]. - Highlights: • First compound in the Nb–Os–B system. • New twofold superstructure of U{sub 3}Si{sub 2} structure type. • Puckering of Nb-layer responsible for superstructure occurrence. • Chemical bonding studied

  13. A study on laser weldability improvement of newly developed Haynes 282 superalloy

    Science.gov (United States)

    Osoba, Lawrence Opeyemi

    Haynes alloy 282 is a new gamma prime (gamma') precipitation strengthened nickel-base superalloy developed for high temperature applications in land-based and aero turbine engines. Joining is a crucial process both during the manufacturing of new components and repair of service-damaged turbine parts. Unfortunately, the new superalloy cracks during laser beam welding (LBW), which is an attractive technique for joining superalloys components due to its low heat input characteristic that preclude the geometrical distortion of welded components. This research is therefore initiated with the goal of studying and developing an effective approach for preventing or minimizing cracking during LBW of the new superalloy Haynes 282. Careful and detailed electron microscopy and spectroscopy study reveal, for the first time, the formation of sub-micron grain boundary M5B3 particles, in the material. Microstructural study of welded specimens coupled with Gleeble thermo-mechanical physical simulations shows that the primary cause of weld heat affected zone (HAZ) cracking in the alloy is the sub-solidus liquation reaction of intergranular M5B3 borides in the material. Further weldability study showed that the HAZ liquation cracking problem worsens with reduction in welding heat input, which is normally necessary to produce the desired weld geometry with minimum distortion. In order to minimize the HAZ cracking during low heat input laser welding, microstructural modification of the alloy by heat treatment at 1080--1100°C has been developed. The pre-weld heat treatment minimizes cracking in the alloy by reducing the volume fraction of the newly identified M5B3 borides, while also minimizing non-equilibrium grain boundary segregation of boron liberated during dissociation of the boride particles. Further improvement in resistance to cracking was produced by subjecting the material to thermo-mechanically induced grain refinement coupled with a pre-weld heat treatment at 1080

  14. Electrodeposition of alloys or compounds in molten salts and applications

    Directory of Open Access Journals (Sweden)

    Taxil P.

    2003-01-01

    Full Text Available This article deals with the different modes of preparation of alloys or intermetallic compounds using the electrodeposition in molten salts, more particularly molten alkali fluorides. The interest in this process is to obtain new materials for high technology, particularly the compounds of reactive components such as actinides, rare earth and refractory metals. Two ways of preparation are considered: (i electrocoating of the more reactive metal on a cathode made of the noble one and reaction between the two metals in contact, and (ii electrocoating on an inert cathode of the intermetallic compound by coreduction of the ions of each elements. The kinetic is controlled by the reaction at the electrolyte interface. A wide bibliographic survey on the preparation of various compounds (intermetallic compounds, borides, carbides… is given and a special attention is paid to the own experience of the authors in the preparation of these compounds and interpretation of their results.

  15. NASA research on refractory compounds.

    Science.gov (United States)

    Gangler, J. J.

    1971-01-01

    The behavior and properties of the refractory carbides, nitrides, and borides are being investigated by NASA as part of its research aimed at developing superior heat resistant materials for aerospace applications. Fundamental studies on the electronic and defect structures of the carbides indicate that there is promise for improving the strength and ductility of these materials. Studies of the zirconium-carbon-oxygen system show that zirconium oxycarbides of different compositions and lattice parameters can be formed between 1500 and 1900 C and are stable below 1500 C. More applied studies show that hot working generally improves the microstructure and therefore the strength of TiC and NbC. Sintering studies on UN indicate that very high densities can be achieved. Hot pressing of cermets of HfN and HfC produces good mechanical properties for high temperature bearing applications.

  16. Interaction Between Second-Phase Particle Dissolution and Abnormal Grain Growth in an Austenitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    J.C. Dutra

    2002-09-01

    Full Text Available The continuing development of stainless steels has resulted in complex steel compositions with substantial amounts of alloying elements. The benefits of such additions invariably come attached to unavoidable disadvantages. One of the most critical item is the potential microstructural instability of the material. Alloying elements may be in a supersaturated solid solution, in which the precipitation of carbides, nitrides, borides and intermetallic phases occurs in a wide range of temperatures. In order to dissolve the mentioned precipitates, solution annealing is commonly performed. However, at the temperature range in which this treatment is carried out, the onset of abnormal grain growth can occur. The interaction between the dissolution of these second-phase particles and the occurrence of abnormal grain growth is investigated in this work. This study also shows that the thermodynamics and the kinetics of dissolution of precipitates may be used to predict whether abnormal grain growth takes place.

  17. Vapor-phase fabrication and properties of continuous-filament ceramic composites.

    Science.gov (United States)

    Besmann, T M; Sheldon, B W; Lowden, R A; Stinton, D P

    1991-09-06

    The continuous-filament ceramic composite is becoming recognized as necessary for new, high-temperature structural applications. Yet because of the susceptibility of the filaments to damage from traditional methods for the preparation of ceramics, vapor-phase infiltration has become the fabrication method of choice. The chemical vapor infiltration methods for producing these composites are now being studied in earnest, with the complexity of filament weaves and deposition chemistry being merged with standard heat and mass-transport relationships. Two of the most influential effects on the mechanical properties of these materials are the adhesion and frictional force between the fibers and the matrix, which can be controlled by a tailored interface coating. A variety of materials are available for producing these composites including carbide, nitride, boride, and oxide filaments and matrices. Silicon carbide-based materials are by far the most advanced and are already being used in aerospace applications.

  18. New method for synthesis of metal carbides, nitrides and carbonitrides

    Energy Technology Data Exchange (ETDEWEB)

    Koc, R.; Folmer, J.S.; Kodambaka, S.K. [Southern Illinois Univ., Carbondale, IL (United States)] [and others

    1997-04-01

    The purpose of this work is to develop a novel synthesis method using a carbothermic reduction reaction of carbon coated precursors for producing high purity, submicron, non-agglomerated powders of metal carbide, metal nitride and metal boride systems. The authors also want to demonstrate the advantages of the process and provide information on the applicability of the process for synthesizing related advanced ceramic powders (e.g. SiC, WC, TiN, TiB{sub 2}, Si{sub 3}N{sub 4}). During the FY96 of the project, steps are taken to investigate the reaction mechanisms and phase evolution during the formation of TiC from carbon coated titania precursors and to produce submicron TiC powders with desired stoichiometries. Depending on the carbon content in the coated titania precursor, TiC powder was produced with different stoichiometries (different amount of oxygen and free carbon).

  19. Transient liquid-phase bonding of ODS steels

    Energy Technology Data Exchange (ETDEWEB)

    Noto, H., E-mail: s25093145w@eng.hokudai.ac.jp [Materials Science and Engineering, Graduate School of Engineering, Hokkaido University, N-13, W-8, Kita-ku, Hokkaido Sapporo 060-8628 (Japan); Ukai, S.; Hayashi, S. [Materials Science and Engineering, Graduate School of Engineering, Hokkaido University, N-13, W-8, Kita-ku, Hokkaido Sapporo 060-8628 (Japan)

    2011-10-01

    The use of transient liquid-phase bonding of 9CrODS steels using Fe-3B-2Si-0.5C filler was investigated for bonding temperature of 1180 deg. C and hold times of 0.5-4.0 h. The sequential process, consisting of isothermal melting, solidification and homogenization, was confirmed for bonding the 9CrODS steel. The precipitation of chromium boride found in 19CrODS steel is avoided in 9CrODS steel due to the lower Cr content. Silicon tends to be slightly enriched inside the bonding zone. Agglomeration and coarsening of Y{sub 2}O{sub 3} particles in 9CrODS steel lead to softening inside the bonding zone formed by incipient melting of the foil bonding alloy, and in a diffusion affected zone (DAZ) adjacent to the bonding zone.

  20. Development of titanium diboride coatings deposited by PACVD

    Energy Technology Data Exchange (ETDEWEB)

    Pfohl, C.; Bulak, A.; Rie, K.-T. [Technische Univ. Braunschweig (Germany). Inst. fuer Oberflaechentechnik und Plasmatechnische Werkstoffentwicklung

    2000-09-01

    TiB{sub 2} appears to be a promising material for the wear protection in various tribological systems, e.g. the diecasting of Al. This study focuses on the development of titanium boride coatings deposited by PACVD, a deposition method which is most suitable for the coating of substrates with complex shapes. All layers analysed are very smooth and exhibit a quasi-amorphous fracture surface. XRD and TEM analysis indicate a nanocrystalline structure with grain sizes in the order of 2 nm. The diffraction patterns can well be correlated to titanium diboride. WDS reveals an over stoichiometric B/Ti ratio. The layer hardness reaches the value of 33 GPa and the critical load in scratch tests rises to 35 N. Neither 100Cr6 nor Al as a counterpart in pin-on-disk tests leads to wear of the coating. (orig.)