WorldWideScience

Sample records for sub-2 microm particle

  1. Study on the genotoxicity of HA/ZrO{sub 2} composite particles in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Quan, Renfu, E-mail: quanrenfu8@yahoo.com [Xiaoshan Traditional Chinese Medical Hospital, ZhengJiang Province 311200 (China); Tang, Yanghua; Huang, Zhongming; Xu, Jinwei [Xiaoshan Traditional Chinese Medical Hospital, ZhengJiang Province 311200 (China); Wu, Xiaochen [School of Materials Science and Engineering, Shanghai University, Shanghai (China); Yang, Disheng [Department of Orthopedics, the second Affiliated Hospital, Medical College of Zhejiang University, Hangzhou 310009 (China)

    2013-04-01

    To evaluate the genotoxicity of the HA/ZrO{sub 2} composite particles by using the micronucleus test (MNT) in vitro. HA/ZrO{sub 2} composite particles prepared by sintering at high temperature and pressure, that used powder of HA and ZrO{sub 2} of different proportions, were compared with pure HA particles and pure ZrO{sub 2} particles. The effect of the composite particles on cell proliferation of rabbit mesenchymal stem cells, and its the genotoxicity to rabbit mesenchymal stem cells were detected by MNT method. The MTT test showed that both pure HA particles and composite particles which contained HA promoted cell proliferation of rabbit mesenchymal stem cells, while pure ZrO{sub 2} particles did not, and there was a significant difference (P < 0.05). The MNT test showed no significant difference between the HA group and the negative control group (P > 0.05), but a significant difference between the HA group and the positive control group (P < 0.05). The difference between the ZrO{sub 2} group and the negative control group was significant (P < 0.01), while the difference between the ZrO{sub 2} group and the positive control group was insignificant (P > 0.05). The genotoxicity of the HA/ZrO{sub 2} composite particle increased with a higher proportion of ZrO{sub 2} and an increase in the concentration of the composite, and the 30 wt.% HA/70% ZrO{sub 2} composite with 200 μg/mL concentration showed significant genotoxicity (P < 0.01). - Highlights: ► HA/ZrO{sub 2} composite particles were prepared by sintering used powder of HA and ZrO{sub 2} of different proportions. ► Evaluate the genotoxicity of the HA/ZrO{sub 2} composite particle in vitro micronucleus test (MNT). ► The genotoxicity of the HA/ZrO{sub 2} composite particle increased with an increase in the proportion of ZrO{sub 2}. ► The 30%wtHA/70% ZrO{sub 2} composite with 200 μg/mL concentration showed significant genotoxicity.

  2. Adsorption of NO{sub 2} on carbon aerosols particles at the low ppb-level

    Energy Technology Data Exchange (ETDEWEB)

    Kalberer, M.; Ammann, M.; Baltensperger, U.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    The adsorption of NO{sub 2} at the low ppb-level (3-40 ppb) on carbon aerosol particles was investigated. A sticking coefficient of about 2.10{sup -4} was found, similar to that in previous studies using radioactively labeled {sup 13}NO{sub 2}. (author) 2 figs., 2 refs.

  3. Effect of particle size on the photochromic response of PWA/SiO{sub 2} nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Feng-Hsi [Tamkang University, Department of Chemical and Materials Engineering (China); Chen, Ching-Chung [Tamkang University, Energy and Opto-Electronic Materials Research Center (China); Lin, Dar-Jong; Don, Trong-Ming; Cheng, Liao-Ping, E-mail: lpcheng@mail.tku.edu.t [Tamkang University, Department of Chemical and Materials Engineering (China)

    2010-10-15

    A series of photochromic phosphotungstic acid (PWA)/SiO{sub 2} composites were synthesized using the sol-gel method. Depending on the feeding schedule of PWA during synthesis, the size of the formed PWA/SiO{sub 2} particles varied considerably from as small as 1.2 nm to ca. 10 nm. With decreasing silica particle size, the total contact area/interaction between SiO{sub 2} and PWA increases, as revealed by FT-IR and solid-state {sup 29}Si-NMR analyses. Particularly, when the size of PWA/SiO{sub 2} is {approx}1 nm, crystallization of PWA is inhibited, and PWA presents as amorphous molecular entities distributing uniformly in the SiO{sub 2} host, which is in evidence in the XRD spectroscopy and HR-TEM imaging. In contrast, substantial crystallization of PWA takes place when PWA/SiO{sub 2} particles are as large as 10 nm, in which case less amount of surface free Si-OH is available for PWA to make bonds with. Photochromism occurs activated by ultraviolet light irradiation. The rate of coloration/bleaching is found to depend strongly on the particle size of PWA/SiO{sub 2}; specifically, the rate increases twice when the particle size is reduced from 10 nm to 1.2 nm.

  4. Extraction of negative pionlike particles from a H{sub 2} or D{sub 2} gas discharge plasma in magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Uramoto, Joshin

    1995-09-01

    Electron density in outside region of H{sub 2} or D{sub 2} gas discharge plasma along magnetic field, is abruptly reduced as H{sup -} or D{sup -} ions are produced. From the region, negative pionlike particles are extracted together with H{sup -} or D{sup -} ions. Then, a positive bias voltage is necessary for the beam collector of magnetic mass analyzer. (author).

  5. Sub 2 nm Particle Characterization in Systems with Aerosol Formation and Growth

    Science.gov (United States)

    Wang, Yang

    Aerosol science and technology enable continual advances in material synthesis and atmospheric pollutant control. Among these advances, one important frontier is characterizing the initial stages of particle formation by real time measurement of particles below 2 nm in size. Sub 2 nm particles play important roles by acting as seeds for particle growth, ultimately determining the final properties of the generated particles. Tailoring nanoparticle properties requires a thorough understanding and precise control of the particle formation processes, which in turn requires characterizing nanoparticle formation from the initial stages. The knowledge on particle formation in early stages can also be applied in quantum dot synthesis and material doping. This dissertation pursued two approaches in investigating incipient particle characterization in systems with aerosol formation and growth: (1) using a high-resolution differential mobility analyzer (DMA) to measure the size distributions of sub 2 nm particles generated from high-temperature aerosol reactors, and (2) analyzing the physical and chemical pathways of aerosol formation during combustion. Part. 1. Particle size distributions reveal important information about particle formation dynamics. DMAs are widely utilized to measure particle size distributions. However, our knowledge of the initial stages of particle formation is incomplete, due to the Brownian broadening effects in conventional DMAs. The first part of this dissertation studied the applicability of high-resolution DMAs in characterizing sub 2 nm particles generated from high-temperature aerosol reactors, including a flame aerosol reactor (FLAR) and a furnace aerosol reactor (FUAR). Comparison against a conventional DMA (Nano DMA, Model 3085, TSI Inc.) demonstrated that the increased sheath flow rates and shortened residence time indeed greatly suppressed the diffusion broadening effect in a high-resolution DMA (half mini type). The incipient particle

  6. A NO/N{sub 2}O-classification system of single fuel particles

    Energy Technology Data Exchange (ETDEWEB)

    Winter, F.; Wartha, C.; Hofbauer, H. [Institute of Chemical Engineering, Fuel Technology and Environmental Technology, Vienna (Austria)

    1997-12-31

    The formation rates of the nitrogen containing species of NO, N{sub 2}O, HCN and the emissions of hydrocarbons, CO, CO{sub 2} of various fuels have been measured during devolatilization and char combustion. FT-IR, ND-IR, mass spectroscopy, GC-ECD, chemi-luminescence, a paramagnetic technique, and flame ionization have been used for gas analysis. The fuels range from different wooden fuels (spruce-wood chips, beech-wood spheres, wooden pressboard and wooden hardboard chips), straw pellets to sewage sludge pellets, spherical sub-bituminous and bituminous coal particles. A classification system is developed based on the nitrogen content of the fuel and its conversion to NO, N{sub 2}O, and HCN. In a detailed analysis it is distinguished between the conversions of volatile-nitrogen and char-nitrogen. (author)

  7. Generation of MoS{sub 2} quantum dots by laser ablation of MoS{sub 2} particles in suspension and their photocatalytic activity for H{sub 2} generation

    Energy Technology Data Exchange (ETDEWEB)

    Baldoví, Herme G.; Latorre-Sánchez, Marcos; Esteve-Adell, Iván [Universitat Politècnica de València, Instituto Universitario de Tecnología Química CSIC-UPV and Departamento de Química (Spain); Khan, Anish; Asiri, Abdullah M. [King Abdulaziz University, Center of Excellence for Advanced Materials Research (Saudi Arabia); Kosa, Samia A. [King Abdulaziz University, Chemistry Department, Faculty of Science (Saudi Arabia); Garcia, Hermenegildo, E-mail: hgarcia@qim.upv.es [Universitat Politècnica de València, Instituto Universitario de Tecnología Química CSIC-UPV and Departamento de Química (Spain)

    2016-08-15

    MoS{sub 2} quantum dots (QDs) have been obtained in colloidal suspensions by 532 nm laser ablation (7 ns fwhp/pulse, 50 mJ/pulse) of commercial MoS{sub 2} particles in acetonitrile. High-resolution transmission electron microscopy images show a lateral size distribution from 5 to 20 nm, but a more homogeneous particle size of 20 nm can be obtained by silica gel chromatography purification in acetonitrile. MoS{sub 2} QDs obtained by laser ablation are constituted by 3–6 MoS{sub 2} layers (1.8–4 nm thickness) and exhibit photoluminescence whose λ{sub PL} varies from 430 to 530 nm depending on the excitation wavelength. As predicted by theory, the confinement effect and the larger periphery in MoS{sub 2} QDs increasing the bandgap and having catalytically active edges are reflected in an enhancement of the photocatalytic activity for H{sub 2} generation upon UV–Vis irradiation using CH{sub 3}OH as sacrificial electron donor due to the increase in the reduction potential of conduction band electrons and the electron transfer kinetics.

  8. Nanocrystalline oxide (Y{sub 2}O{sub 3}, Dy{sub 2}O{sub 3}, ZrO{sub 2}, NiO) coatings on BaTiO{sub 3} submicron particles by precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Bassano, Alessio [University of Genoa, Department of Chemical and Process Engineering (Italy); Buscaglia, Vincenzo, E-mail: v.buscaglia@ge.ieni.cnr.i [National Research Council, Institute for Energetics and Interphases (Italy); Sennour, Mohamed [Ecole des Mines de Paris, Centre des Materiaux (France); Buscaglia, Maria Teresa; Viviani, Massimo [National Research Council, Institute for Energetics and Interphases (Italy); Nanni, Paolo [University of Genoa, Department of Chemical and Process Engineering (Italy)

    2010-02-15

    Nanocoatings (5-20 nm) of different compounds on fine BaTiO{sub 3} particles were obtained by means of precipitation processes. Homogeneous and smooth shells of Y(OH)CO{sub 3} and Dy(OH)CO{sub 3} were grown from nitrate solutions in the presence of urea. An irregular coating consisting of zirconia nanoparticles was produced from zirconyl nitrate solution using ammonia as a precipitating agent after adsorption of a polymeric polyelectrolyte on the BaTiO{sub 3} surface. Composite particles with a peculiar morphology were obtained by inducing heterogeneous nucleation and growth of Ni(OH){sub 2} lamellae on the BaTiO{sub 3} surface. The different shells can be transformed in a nanocrystalline coating of the corresponding oxide (Y{sub 2}O{sub 3}, Dy{sub 2}O{sub 3}, ZrO{sub 2}, NiO) by calcination at moderate temperatures (400-700 {sup o}C). The overall results indicate that precipitation from solution represents a versatile process to grow a second-phase layer on the surface of BaTiO{sub 3} particles. This approach can be used as an alternative to mechanical wet mixing for controlled doping of ferroelectric materials and for the fabrication of composite materials with specific geometry of the two-phase assembly.

  9. Spent UO{sub 2} TRISO coated particles. Instant release fraction and microstructure evolution

    Energy Technology Data Exchange (ETDEWEB)

    Curtius, Hildegard; Kaiser, Gabriele; Lieck, Norman; Guengoer, Murat; Klinkenberg, Martina; Bosbach, Dirk [Research Center Juelich (Germany). Inst. of Energy and Climate Research IEK-6: Nuclear Waste Management and Reactor Safety

    2015-09-01

    The impact of burn-up on the instant release fraction (IRF) from spent fuel was studied using very high burn-up UO{sub 2} fuel (∝ 100 GWd/t) from a prototype high temperature reactor (HTR). TRISO (TRi-structural-ISO-tropic) particles from the spherical fuel elements contain UO{sub 2} fuel kernels (500 μm diameter) which are coated by three tight layers ensuring the encapsulation of fission products during reactor operation. After cracking of the tight coatings {sup 85}Kr and {sup 14}C as {sup 14}CO{sub 2} were detected in the gas fraction. Xe was not detected in the gas fraction, although ESEM (Environmental Scanning Electron Microscope) investigations revealed an accumulation in the buffer. UO{sub 2} fuel kernels were exposed to synthetic groundwater under oxic and anoxic/reducing conditions. U concentration in the leachate was below the detection limit, indicating an extremely low matrix dissolution. Within the leach period of 276 d {sup 90}Sr and {sup 134/137}Cs fractions located at grain boundaries were released and contribution to IRF up to max. 0.2% respectively 8%. Depending on the environmental conditions, different release functions were observed. Second relevant release steps occurred in air after ∝ 120 d, indicating the formation of new accessible leaching sites. ESEM investigations were performed to study the impact of leaching on the microstructure. In oxic environment, numerous intragranular open pores acting as new accessible leaching sites were formed and white spherical spots containing Mo and Zr were identified. Under anoxic/reducing conditions numerous metallic precipitates (Mo, Tc and Ru) filling the intragranular pores and white spherical spots containing Mo and Zr, were detected. In conclusion, leaching in different geochemical environments influenced the speciation of radionuclides and in consequence the stability of neoformed phases, which has an impact on IRF.

  10. Particle-specific toxicity and bioavailability of cerium oxide (CeO{sub 2}) nanoparticles to Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xinping; Pan, Haopeng [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Wang, Peng, E-mail: p.wang3@uq.edu.au [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); The University of Queensland, School of Agriculture and Food Sciences, St. Lucia, Queensland 4072 (Australia); Zhao, Fang-Jie [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom)

    2017-01-15

    Highlights: • The phytotoxicity and uptake of CeO{sub 2} NPs were examined in Arabidopsis. • CeO{sub 2} NPs stimulated plant growth at low doses but were toxic at high doses. • The toxicity was due to the NPs per se, rather than from the dissolved Ce ions. • A similar up-translocation factor was found for CeO{sub 2} NPs, bulk CeO{sub 2} and Ce ions. - Abstract: The use of manufactured cerium oxide nanoparticles (CeO{sub 2}-NPs) in consumer products has increased markedly over the past decade, and their release into natural ecosystems is unavoidable. This study investigated the phytotoxicity and uptake of CeO{sub 2}-NPs in Arabidopsis thaliana grown in an agar medium. Although low concentrations of CeO{sub 2}-NPs had stimulatory effects on plant growth, at higher concentrations, CeO{sub 2}-NPs reduced growth and had adverse effects on the antioxidant systems and photosystem. Importantly, the toxicity resulted from the nanoparticles per se, rather than from the dissolved Ce ions. CeO{sub 2}-NPs were taken up and subsequently translocated to shoot tissues, and transmission electron microscopy (TEM) showed the presence of a large number of needle-like particle aggregations in the intercellular regions and the cytoplasm of leaf cells. The up-translocation factor to shoots was independent of the concentrations of Ce in the roots and the supplied forms of Ce (i.e. CeO{sub 2}-NPs, CeO{sub 2}-bulk, and ionic Ce), suggesting that endocytosis is likely to be a general mechanism responsible for the translocation of these Ce compounds. These findings provide important information regarding the toxicity and uptake of CeO{sub 2}-NPs in plants, which needs to be considered in environmental risk assessment for the safe use and disposal of CeO{sub 2}-NPs.

  11. Teicoplanin bonded sub-2 μm superficially porous particles for enantioseparation of native amino acids.

    Science.gov (United States)

    Min, Yi; Sui, Zhigang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2015-10-10

    Superficially porous particles (SPPs) demonstrate superior efficiency than totally porous particles in chiral separations. In order to obtain high efficiency and fast separation, sub-2 μm SPPs with high surface area are synthesized, and with teicoplanin bonded, such materials are successfully applied into the rapid enantioseparation of native amino acids. In brief, 1.27 ± 0.06 μm nonporous silica particles are prepared by a modified seeded growth method, followed by mesoporous shell fabrication via one-pot templated dissolution and redeposition strategy, and pore size expansion via acid-refluxing. The diameter of the formed SPPs is 1.49 ± 0.04 μm, with the shell thickness as 206 nm. Nitrogen physisorption experiments show that the Brunauer-Emmett-Teller (BET) specific surface area is 213.6 m(2)/g and pore size is 9 nm. After teicoplanin derivatization with bonding capacity as 83.3 μmol/g, the prepared chiral stationary phase is packed into a stainless steel tube with the geometry of 50 mm × 2.1 mm i.d.. In less than 6.4 min, six native amino acids (norleucine, alanine, valine, methionine, leucine, norvaline) are enantioseparated with resolution factors ranging from 1.9 to 5.0. Besides, the resolution for chiral separation is improved with ethanol-water instead of methanol-water as the mobile phase. Moreover, the low temperature gives higher resolution, but longer retention time and higher backpressure. Finally, the effect of flow rate on enantiomeric separation is studied and fast chiral separation within 1 min is obtained with flow rate of 0.4 mL/min. All these results show that the synthesized teicoplanin bonded sub-2 μm SPPs have great potential to achieve the enantioseparation of native amino acids with high resolution and rapid speed. Copyright © 2015. Published by Elsevier B.V.

  12. UO<sub>2 Particle Standards: Synthesis, Purification & Planchet Preparation

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Christopher A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Anheier, Norman C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-31

    The IAEA has previously indicated its desire for reliable provision of suitable reference materials in support of environmental sample analysis and sustained advancement at the Department of Safeguards, as laid out in the Long Term R&D plan (LTRD 10.1 & 10.2). In a recent meeting between NPAC, the IAEA and PNNL, this pressing need was directly outlined by the IAEA as having two main objectives. The first pertains to current operations, such as instrument calibrations and evaluation of bias across the Network of Analytical Laboratories and requires particles on the order of 300-500 nm in diameter. The second need for particle reference material would directly support the IAEA’s ongoing R&D efforts and calls for smaller particles ranging from 50 -100 nm in size. As such, the IAEA has expressed a great deal of interest in the newly established synthesis capabilities at PNNL, initially cultivated through a PNNL LDRD project to address the particle-standards shortcomings for uranium oxide material. The joint meeting concluded with a request by the IAEA for 1-2 planchet samples containing PNNL’s UO<sub>2 particulate material, to be delivered in the near-term. This report outlines the steps taken to meet that request and includes some basic characteristics of the samples sent to the IAEA.

  13. Analysis of the solidification and microstructure of two aluminium alloys reinforced with TiB{sub 2} particles

    Energy Technology Data Exchange (ETDEWEB)

    Egizabal, Pedro; Garcia de Cortazar, Maider [Fundacion Inasmet E-20009 Donostia-San Sebastian (Spain); Torregaray, Amaia [University of Basque Country UPV/EHU E-48012, Bilbo-Bilbao (Spain); Veillere, Amelie; Silvain, Jean-Francois [CNRS, Universite de Bordeaux, ICMCB 87 Avenue du Docteur Albert Schweitzer, 33608 Pessac (France); Douin, Joel [CEMES-CNRS 29 Rue Jeanne Marvig, BP 94347, 31055 Toulouse Cedex 4 (France)

    2011-09-15

    Two aluminium alloys with 6 wt% TiB{sub 2} particles are studied for applications where increased wear resistance and mechanical strength at high temperature are required. The incorporation of hard ceramic particles has a strong influence on the microstructure and properties of the alloys. TiB{sub 2} particles play an important role in the nucleation of the different phases of the alloys during solidification, and in the reduction of grain size and porosity. The solidification patterns of Al-Si{sub 7}Mg{sub 0.3} + TiB{sub 2} (6 wt%) and Al-Cu{sub 5}MgTi+TiB{sub 2} (6 wt%) materials are compared to their corresponding non-reinforced alloys, and the microstructures are analyzed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. One-pot synthesis of Cu{sub 2}O octahedron particles and their catalytic application

    Energy Technology Data Exchange (ETDEWEB)

    Li, Biao; Li, Dan; Mu, Lei; Yang, Sung Ik [Dept. of Applied Chemistry, Kyung Hee University, Yongin (Korea, Republic of)

    2017-04-15

    We report a facile one-step synthesis method of cuprous oxide (Cu{sub 2}O) hollow octahedrons with controllable size Cu{sub 2}O exhibited a great catalytic activity for the reduction of methylene blue by N{sub 2}H{sub 4} as well as NABH{sub 4}.

  15. Optimizing conditions of preparation of thermoresponsive SiO{sub 2}-POEGMA particles via AGET-ATRP

    Energy Technology Data Exchange (ETDEWEB)

    Du, Zhiping, E-mail: duzhiping@sxu.edu.cn [Institute of Resources and Environment Engineering, Shanxi University, No. 92 Wucheng Road, Taiyuan 030006 (China); China Research Institute of Daily Chemical Industry, No.34 Wenyuan Road, Taiyuan 030001 (China); Sun, Xiaofeng; Tai, Xiumei; Wang, Guoyong; Liu, Xiaoying [China Research Institute of Daily Chemical Industry, No.34 Wenyuan Road, Taiyuan 030001 (China)

    2015-02-28

    Graphical abstract: - Highlights: • Thermosensitive SiO{sub 2} nanoparticles were prepared with POEGMA via AGET-ATRP. • Reaction conditions were optimized. • Thermosensitive properties of SiO{sub 2}-POEGMA particles were pronounced. - Abstract: Thermosensitive poly(ethylene glycol) methyl ether methacrylate (POEGMA) was grafted on SiO{sub 2} nanoparticles using activators generated by electron transfer atom transfer radical polymerization (AGET-ATRP) technique. The effects of the amount of ligand, catalyst, ascorbic acid and monomer, as well as the reaction temperature and time were systematically investigated and optimized to get a high grafting density. The structure of the hybrid materials was characterized by Fourier transform infrared (FTIR) spectroscopy, and the morphology was characterized by transmission electron microscopy (TEM) observations. Thermosensitive properties of SiO{sub 2}-POEGMA particles were investigated at different grafting densities by turbidity measurements.

  16. Microplastic deformation of TiB/sub 2/ particles during vibrocrushing and pressing in high pressure chambers

    Energy Technology Data Exchange (ETDEWEB)

    Ordan' yan, S.S.; Kravchik, A.E.; Ponomarenko, V.A.; Chunov, V.D. (Leningradskij Tekhnologicheskij Inst. (USSR))

    1984-04-01

    The character of plastic strain in titanium diboride particles is described. It is shown that during titanium diboride vibrocrushing unlike that of carbide there is practically no microplastic deformation that is observed only when TiB/sub 2/ particles are squeezed in high-pressure chambers at pressures not less than 3GPa.

  17. Assembly and luminescence properties of lanthanide-polyoxometalates/polyethyleneimine/SiO{sub 2} particles with core–shell structure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jun, E-mail: junwang924@yahoo.com.cn; Fan, Shaohua; Zhao, Weiqian; Zhang, Hongyan

    2013-01-01

    In this paper, two lanthanide-polyoxometalate (LnW{sub 10}) complexes were bonded on the surface of the polyethyleneimine (PEI)-modified silica nanoparticles with different sizes, resulting in the formation of LnW{sub 10}/PEI/SiO{sub 2} particles. The hybrid core–shell particles were characterized by infrared, luminescent spectra, scanning electronic microscope, and transmission electronic microscope. The particles obtained exhibit the fine spherical core–shell structure and the excellent luminescence properties. The luminescence spectra studies revealed that the formation of LnW{sub 10}/PEI/SiO{sub 2} particles and the size of particle have an influence on the luminescence properties of lanthanide ions. - Highlights: ► SiO{sub 2}/polyethyleneimine (PEI) shows the chemisorption for Ln-polyoxometalates (LnW{sub 10}). ► The core-shell LnW{sub 10}/PEI/SiO{sub 2} nanoparticles with different sizes were fabricated. ► The hybrid particles exhibit the excellent luminescence properties. ► The sizes of particles affect the luminescence properties of lanthanide ions.

  18. Highly dispersive α″-Fe{sub 16}N{sub 2} particle synthesis using hydroxyapatite coating

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, Daisuke; Kinemuchi, Yoshiaki, E-mail: y.kinemuchi@aist.go.jp; Suzuki, Kazuyuki; Towata, Atsuya; Yasuoka, Masaki

    2015-05-15

    Alpha″-Fe{sub 16}N{sub 2} nanoparticles (NPs) with high magnetic crystalline anisotropy are useful for practical applications such as recording media. However, due to their strongly aggregated and/or sintered form, which occurs during synthesis, the utilization of the NPs has been limited thus far. Here, we report a method for synthesizing highly dispersive α″-Fe{sub 16}N{sub 2} NPs using hydroxyapatite (HAp). The chemically and thermally stable structure of the HAp coating results in the isolation of individual NPs, such that sintering is prevented during synthesis. Additionally, the acicular shape of the HAp crystal did not hinder gas diffusion during the gas reaction. Finally, HAp can be removed by a chelating agent without deteriorating the magnetic properties, resulting in highly dispersive α″-Fe{sub 16}N{sub 2} NPs. - Graphical abstract: Synthesis process of highly dispersive α″-Fe{sub 16}N{sub 2} particles using hydroxyapatite coating and SEM images of nanoparticles. - Highlights: • Highly dispersed α″-Fe{sub 16}N{sub 2} NPs were synthesized using hydroxyapatite (HAp). • HAp coating was stable chemically and thermally during gas reaction of α″-Fe{sub 16}N{sub 2} synthesis. • The magnetic property of the resultant Fe{sub 16}N{sub 2} NPs are M{sub s} of 170 emu/g and H{sub C} of 2450 Oe.

  19. Partitioning characteristics and particle size distributions of heavy metals in the O{sub 2}/RFG waste incineration system

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jyh-Cherng, E-mail: jcchen@sunrise.hk.edu.tw [Department of Safety, Health and Environmental Engineering, HungKuang University, No. 34, Chung-Chie Rd., Shalu, Taichung County 43302, Taiwan (China); Huang, Jian-Sheng [Department of Safety, Health and Environmental Engineering, HungKuang University, No. 34, Chung-Chie Rd., Shalu, Taichung County 43302, Taiwan (China)

    2009-12-30

    This study applies the oxygen/recycled flue gas (O{sub 2}/RFG) combustion technology for waste incineration and investigates the effects of different RFG rates on the concentrations of gas pollutants as well as the partitioning characteristics and particle size distributions of five heavy metals (Cr, Cu, Pb, Zn, and Cd). Experimental results show that the combustion efficiency can be improved and the concentration of CO{sub 2} is increased by appropriately controlling the RFG rate in the O{sub 2}/RFG incineration system. The partitioning characteristics and size distributions of heavy metals in O{sub 2}/RFG combustion system are different from those in general air combustion system. Under O{sub 2}/RFG combustion system, the partitioning percentages of heavy metals in sand bed, bottom ash, and collected ash are increased. The particle size distributions of heavy metals display the triple-peak curves. As the RFG rate rises, the concentrations of volatile heavy metals are increased in small-size (<1 {mu}m) fly ash, decreased in medium-size (1-10 {mu}m) fly ash and increased in large-size (>10 {mu}m) fly ash. These phenomena will benefit to increase the overall control efficiency of heavy metals in the incineration system.

  20. Lattice strain estimation for CoAl{sub 2}O{sub 4} nano particles using Williamson-Hall analysis

    Energy Technology Data Exchange (ETDEWEB)

    Aly, Kamal A., E-mail: kamalaly2001@gmail.com [Physics Department, Faculty of Science & Arts, Khulais, University of Jeddah, Jiddah (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut (Egypt); Khalil, N.M. [Chemistry Department, Faculty of Science & Arts, Khulais, University of Jeddah, Jiddah (Saudi Arabia); Refractories, Ceramics and Building Materials Department, National Research Centre, 12311 Cairo (Egypt); Algamal, Yousif [Chemistry Department, Faculty of Science & Arts, Khulais, University of Jeddah, Jiddah (Saudi Arabia); Saleem, Qaid M.A. [Chemistry Department, Faculty of Science & Arts, Khulais, University of Jeddah, Jiddah (Saudi Arabia); Chemistry Department, Faculty of Education, Aden University, Sabwa (Yemen)

    2016-08-15

    CoAl{sub 2}O{sub 4} nanoparticles were prepared via coprecipitation technique through mixing 1:1 M ratio of cobalt nitrate and aluminium nitrate solutions at pH 10. CoAl{sub 2}O{sub 4} crystalline phase was confirmed by X-ray diffraction. Scanning electron microscopy (SEM) result reveals that the particles of CoAl{sub 2}O{sub 4} fired at 900 °C were relatively small (21 nm) and uniform. Increased temperature to 1200 °C gives rise to blocky particles and changes in the powders shape, that because of agglomeration came from the calcination of CoAl{sub 2}O{sub 4}. Furthermore, the particle size increase with increasing the calcinated temperature. The crystalline sizes were evaluated by using X-ray peak broadening analysis suggested by Williamson-Hall (W-H) analysis. It was successfully applied for lattice strain and to calculate mechanical stress and energy density values using different three models namely uniform deformation model (UDM), uniform deformation stress model (UDSM) and uniform deformation energy density model (UDEDM). Also, the root mean square strain was determined. These models gave a different strain values which suggested an isotropic nature of the nanoparticles. Besides, the obtained results W-H analysis are in good agreement with that deduced from SEM analysis and Scherrer's formula. - Highlights: • CoAl{sub 2}O{sub 4} nanoparticles were prepared via coprecipitation technique. • CoAl{sub 2}O{sub 4} nanoparticles were characterized by SEM and XRD. • the lattice size and strain were investigated according to W-H analysis. • The latic size were investigated by W-H analysis, SEM and Sherrar's method. • The root mean square strain was determined.

  1. Nanoscale mechanochemical wear of phosphate laser glass against a CeO{sub 2} particle in humid air

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jiaxin, E-mail: yujiaxin@swust.edu.cn [Key Laboratory of Testing Technology for Manufacturing Process, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010 (China); He, Hongtu; Zhang, Yafeng [Key Laboratory of Testing Technology for Manufacturing Process, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010 (China); Hu, Hailong [Analysis and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China)

    2017-01-15

    Highlights: • Friction components of phosphate glass/CeO{sub 2} pair in humid air were quantified to understand the friction mechanism. • Severe nanoscale wear was directly observed by AFM topography on both phosphate glass and CeO{sub 2} particle in humid air. • The wearless behaviors of phosphate glass in vacuum were confirmed by the AFM phase image. • Capillary water bridge induced corrosion plays an important role in the mechanochemical wear of phosphate glass in air. - Abstract: Using an atomic force microscope, the friction and wear of phosphate laser glass against a CeO{sub 2} particle were quantitatively studied both in humid air and in vacuum, to reveal the water molecules induced mechanochemical wear mechanism of phosphate laser glass. The friction coefficient of the glass/CeO{sub 2} pair in air was found to be 5–7 times higher than that in vacuum due to the formation of a capillary water bridge at the friction interface, with a contribution of the capillary-related friction to the total friction coefficient as high as 65–79%. The capillary water bridge further induced a serious material removal of glass and CeO{sub 2} particle surfaces, while supplying both a local liquid water environment to corrode the glass surface and a high shearing force to assist the stretching of the Ce−O−P bond, accelerating the reaction between water and the glass/CeO{sub 2} pair. In vacuum, however, no discernable wear phenomena were observed, but the phase images captured by AFM tapping mode suggested the occurrence of potential strain hardening in the friction area of the glass surface.

  2. A new strategy on utilizing nitrogen doped TiO{sub 2} in nanostructured solar cells: Embedded multifunctional N-TiO{sub 2} scattering particles in mesoporous photoanode

    Energy Technology Data Exchange (ETDEWEB)

    Shogh, Shiva [Department of Physics, Sharif University of Technology, Tehran 11365-9161 (Iran, Islamic Republic of); Mohammadpour, Raheleh [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran 14588-89694 (Iran, Islamic Republic of); Iraji zad, Azam, E-mail: Iraji@sharif.edu [Department of Physics, Sharif University of Technology, Tehran 11365-9161 (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran 14588-89694 (Iran, Islamic Republic of); Taghavinia, Nima [Department of Physics, Sharif University of Technology, Tehran 11365-9161 (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran 14588-89694 (Iran, Islamic Republic of)

    2015-12-15

    Highlights: • N-doped TiO{sub 2} scattering particles were synthesized for embedding into commercial photoanode of dye sensitized solar cells. • Embedded scatterers improved optical and electrical features of the cells. • These multifunctional scatterers increased cell performance up to 17%. - Abstract: Aggregated sub-micron size nitrogen doped TiO{sub 2} (N-TiO{sub 2}) particles with superior optical and electrical features were successfully synthesized for embedding into commercial mesoporous TiO{sub 2} photoelectrode of dye sensitized solar cells (DSSCs) as the light scattering particles compared to undoped one. X-ray photoelectron spectroscopy and absorption spectra confirmed that the titanium dioxide is sufficiently doped by nitrogen in N-TiO{sub 2} sample. Employing these high-surface N-TiO{sub 2} in mesoporous photoelectrode of solar cells, the power conversion efficiency of 8% has been achieved which shows 17% improvement for the optimum embedded level of doping (30 wt%) compared to commercial photoelectrode without additive; while enhanced efficiency is only 3% embedding undoped sub-micron size TiO{sub 2} particles. These results can introduce the novel multifunctional photoelectrode for nanostructured solar cells with enhanced values of scattering efficiency and improved electrical features including trap states density reduction in comparison to commercial mesoporous photoelectrodes.

  3. Nano ZrO{sub 2} particles in nanocrystalline Fe–14Cr–1.5Zr alloy powders

    Energy Technology Data Exchange (ETDEWEB)

    Xu, W.Z.; Li, L.L.; Saber, M.; Koch, C.C.; Zhu, Y.T., E-mail: ytzhu@ncsu.edu; Scattergood, R.O.

    2014-09-15

    Here we report on the formation of nano ZrO{sub 2} particles in Fe–14Cr–1.5Zr alloy powders synthesized by mechanical alloying. The nano ZrO{sub 2} particles were found uniformly dispersed in the ferritic matrix powders with an average size of about 3.7 nm, which rendered the alloy powders so stable that it retained nanocrystalline structure after annealing at 900 °C for 1 h. The ZrO{sub 2} nanoparticles have a tetragonal crystal structure and the following orientation relationship with the matrix: (0 0 2){sub ZrO2}//(0 0 2){sub Matrix} and [0 1 0]{sub ZrO2}//[1 2 0]{sub Matrix}. The size and dispersion of the ZrO{sub 2} particles are comparable to those of Y–Ti–O enriched oxides reported in irradiation-resistant ODS alloys. This suggests a potential application of the new alloy powders for nuclear energy applications.

  4. Structural, morphological and magnetic properties of NiFe{sub 2}O{sub 4} nano-particles

    Energy Technology Data Exchange (ETDEWEB)

    Alarifi, A. [Chemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Deraz, N.M., E-mail: nmderaz@yahoo.co [Chemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Physical Chemistry Department, Laboratory of Surface Chemistry and Catalysis, National Research Center, Dokki, Cairo (Egypt); Shaban, S. [Refining Division, Egyptian Petroleum Research Institute (EPRI), Nasr City, Cairo (Egypt)

    2009-11-03

    NiFe{sub 2}O{sub 4} nano-particles were synthesized by a simple and cost-effective method using Ni and Fe nitrates and glycine. Significant effect of the ratio between glycine and nitrates on the physical parameters like crystalline phase, crystallite size, and particle size, lattice constant and magnetic properties of the nano-particles has been investigated. The X-ray diffraction, IR and selected-area electron diffraction results indicated that the synthesized nickel ferrite particles have the nanometer size and inverse spinel structure. Room temperature magnetization results showed a ferromagnetic behavior of the NiFe{sub 2}O{sub 4} nano-particles, with saturation specific magnetization values in the range of 2.387-57 emu/g at 15 kOe. The corecivity of the NiFe{sub 2}O{sub 4} nano-powders changed from 65.58 to 148.8 Oe according to the change in the ratio between glycine and nitrates.

  5. Visible active nanocrystalline N-doped anatase TiO{sub 2} particles for photocatalytic mineralization studies

    Energy Technology Data Exchange (ETDEWEB)

    Barkul, R.P. [Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, Sub–campus Osmanabad, 413 501, MS (India); Koli, V.B.; Shewale, V.B. [Department of Chemistry, Shivaji University, Kolhapur, 416 004, MS (India); Patil, M.K. [Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, Sub–campus Osmanabad, 413 501, MS (India); Delekar, S.D., E-mail: sddelekar7@rediffmail.com [Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, Sub–campus Osmanabad, 413 501, MS (India); Department of Chemistry, Shivaji University, Kolhapur, 416 004, MS (India); Department of Chemistry and Biochemistry, Florida State University, Tallahassee, 30306-4390, FL (United States)

    2016-04-15

    Nitrogen-doped TiO{sub 2} nanoparticles (N–TiO{sub 2} NPs) with anatase phase were synthesized by sol–gel method using a single precursor containing titanium (IV) terbutoxide, glacial acetic acid, sodium dodecyl sulphate, ammonia, and urea. X-ray diffraction (XRD) reveals the nanocrystalline nature with anatase phase of all the samples. The particle size of all samples was found in the range of 5–12 nm using transmission electron microscopy (TEM). UV–visible absorption measurements examined that the optical band gap of the doped samples decrease with increase in dopant concentration from 0.0 to 7.0 mol%. Field-emission scanning electron microscopy (FESEM) with energy dispersive atomic X-ray (EDAX) spectroscopy was employed to analyse the morphology and chemical composition of these N–TiO{sub 2} NPs. The photocatalytic activity of bare/doped TiO{sub 2} samples was demonstrated for the degradation of Rhodamine B (RhB) dye under direct sunlight irradiation. The photocatalytic degradation was monitored by measuring the kinetic parameters based on UV–visible spectroscopy as well as the chemical oxygen demand (COD) during the course of the reaction. The effect of dye concentration and pH of the solution on the photocatalytic degradation reaction in the presence of colloidal bare/doped TiO{sub 2} were also studied. The N–TiO{sub 2} catalyst, with a nitrogen concentration of 7.0 mol%, showed the highest activity for photocatalytic mineralization of dye at acidic or alkaline medium than neutral condition under solar light irradiation directly. - Highlights: • Nitrogen doped TiO{sub 2} nanoparticles where synthesized by using simple sol–gel method at room temperature. • N–TiO{sub 2} nanoparticles shows red shift. • Hydroxylation on the surface of TiO{sub 2} increase with increasing nitrogen concentration. • In presence of sunlight N–TiO{sub 2} shows enhancement in degradation of RhB dye.

  6. Fabrication and Characterization of Surrogate TRISO Particles Using 800μm ZrO<sub>2 Kernels

    Energy Technology Data Exchange (ETDEWEB)

    Jolly, Brian C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Helmreich, Grant [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cooley, Kevin M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dyer, John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-07-01

    In support of fully ceramic microencapsulated (FCM) fuel development, coating development work is ongoing at Oak Ridge National Laboratory (ORNL) to produce tri-structural isotropic (TRISO) coated fuel particles with both UN kernels and surrogate (uranium-free) kernels. The nitride kernels are used to increase fissile density in these SiC-matrix fuel pellets with details described elsewhere. The surrogate TRISO particles are necessary for separate effects testing and for utilization in the consolidation process development. This report focuses on the fabrication and characterization of surrogate TRISO particles which use 800μm in diameter ZrO<sub>2 microspheres as the kernel.

  7. Solid-particle erosion of an Al{sub 2}O{sub 3}-SiC-TiC composite

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, M.; Goretta, K.C.; Singh, D.; Routbort, J.L. [Argonne National Lab., IL (United States); Schuldies, J.J. [Industrial Ceramic Technology, Inc., Ann Arbor, MI (United States)

    1996-11-01

    An electrodischarge-machinable Al{sub 2}O{sub 3}-SiC-TiC composite developed by Industrial Ceramic Technology, Inc., has a high fracture toughness, 9.6{+-}0.6 MPm{sup 1/2}, as measured by indentation, and a Vickers hardness of 20.3{+-}0.6 GPa. The composite`s resistance to solid-particle erosion was measured for 143-{mu}m dia SiC particles impacting at 20-90{degree} angles and 50-100 m/s velocities. Erosion rate exhibited a maximum for normal incidence, and the erosion resistance was better than that of commercial Al{sub 2}O{sub 3}. SEM indicated that material wastage was by a combination of brittle fracture and microplasticity.

  8. Heterogeneous photocatalytic degradation of phenanthrene in surfactant solution containing TiO{sub 2} particles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yanlin, E-mail: zhangyl@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou (China); Sino-Forest Applied Research Centre for Pearl River Delta Environment and Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong); Wong, J.W.C. [Sino-Forest Applied Research Centre for Pearl River Delta Environment and Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong); Liu Peihong [School of Chemistry and Environment, South China Normal University, Guangzhou (China); Yuan Min [Research Resources Center, South China Normal University, Guangzhou (China)

    2011-07-15

    Highlights: {yields} Degradation of phenanthrene in surfactant solution and the role of surfactant have been elucidated. {yields} Possible pathway of phenanthrene degradation in surfactant solution is proposed. {yields} The degradation of phenanthrene follows pseudo-second-order kinetics. {yields} It is proved that applying the surfactants as solubilizing agents to remove contaminants from soils followed by photocatalytic degradation is a promising strategy for soil remediation. - Abstract: Photocatalytic degradation of phenanthrene (PHE) over TiO{sub 2} in aqueous solution containing nonionic surfactant micelles was investigated. All photocatalytic experiments were conducted using a 253.7 nm mercury monochromatic ultraviolet lamp in a photocatalytic reactor. The surfactant micelles could provide a nonaqueous 'cage' to result in a higher degradation rate of PHE than in an aqueous solution, but the higher Triton X-100 concentration (more than 2 g/L) lowered the degradation ratio of PHE because the additional surfactant micelles hindered the movement of micelles containing PHE so as to reduce their adsorption onto titania. Pseudo-second-order kinetics was observed for the photocatalytic degradation of PHE. Alkaline solution environment was beneficial to the photocatalytic degradation of PHE. PHE degradation could mainly be attributed to the formation of hydroxyl radicals as evident from the comparison of degradation efficiencies when O{sub 2}, H{sub 2}O{sub 2} and tert-butyl alcohol (TBA) were applied as oxidants or hydroxyl radical scavenger. Based on the GC/MS analysis of the intermediates, the possible pathways of the photocatalytic degradation of PHE were proposed.

  9. Effect of particle size distribution on the magnetic properties {gamma}-Fe{sub 2}O{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hassnain Jaffari, G. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan); Ekiert, Thomas; Unruh, K.M. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Ismat Shah, S., E-mail: ismat@udel.edu [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716 (United States)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Effects of particle size distribution on magnetic properties of {gamma}-Fe{sub 2}O{sub 3} nanoparticles are studied. Black-Right-Pointing-Pointer A new measurement is carried out in which spins were thermally activated below blocking temperature under constant field. Black-Right-Pointing-Pointer Simulations on non-interacting nanoparticle system are compared with experiment. Black-Right-Pointing-Pointer The magnetization differences at the temperature below and around blocking temperature are discussed. Black-Right-Pointing-Pointer Experimental results show reversible magnetization on subsequent cooling-heating cycles. - Abstract: The magnetic response of nanocomposites formed by non-interacting well dispersed {gamma}-Fe{sub 2}O{sub 3} nanoparticles in a polymer matrix is presented. Various low loading fraction of particles in polymer leads to an observation of similar values of blocking temperatures and coercive fields. ac response confirms that particles are non-interacting and follow Neel-Brown model. Effect of particle size distribution on hysteresis behavior and saturation magnetization as a function of temperature is discussed. Since particles have a size distribution, the experimental results of magnetic response are compared with simulations based on Stoner-Wohlfarth model of single size particles. We have devised a measurement method in which a constant magnetic field was applied while the thermal energy is varied by sequentially heating and cooling the sample below the blocking temperature. Nanoparticle-polymer composites show reversible magnetization behavior for sequential heating/cooling cycles. However, simulation based on single size particle system shows irreversible magnetization behavior during the heating and cooling cycles. These observations are qualitatively explained in terms of different behavior of magnetization as a function of temperature for smaller superparamagnetic particles and larger blocked

  10. Particle size effect on Moessbauer parameters in {gamma}-Fe{sub 2}O{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Siddique, M., E-mail: siddique56@hotmail.co [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Ahmed, E. [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Butt, N.M. [Preston Institute of Science and Technology (PINSAT), Preston University, H-8/1, Islamabad (Pakistan)

    2010-09-15

    Nanoparticles of maghemite ({gamma}-Fe{sub 2}O{sub 3}) were synthesized by chemical co-precipitation method for different particle size ranges and Moessbauer spectroscopy was employed to see the particle size effect on the Moessbauer parameters, especially on the average internal magnetic field of the system. It was observed that the internal magnetic field increased with increase in particle size. The contribution of superparamagnetic component for all size ranges is almost equal, i.e. 10%, while the relaxed subspectrum contributes around 50% at all stages. The superparamagnetic component was a quadrupole doublet up to 40 nm and then it transformed into a singlet at larger particle sizes. This indicates that the electric field gradient vanishes for this particular Fe environment and has an ideal cubic symmetry.

  11. Synthesis and effect of copper incorporation on the thermoluminescence and structural properties of SiO{sub 2} particles

    Energy Technology Data Exchange (ETDEWEB)

    Burruel I, S. E.; Cruz V, C.; Salas J, Ch. J. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R. [Universidad de Sonora, Centro de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico); Garcia H, A. R. [Universidad de Sonora, Departamento de Ciencias Quimico Biologicas, 83000 Hermosillo, Sonora (Mexico); Castano, V. M., E-mail: silvia@gimmunison.com [UNAM, Instituto de Fisica, Departamento de Fisica Aplicada y Tecnologia Avanzada, Apdo. Postal 1-1010, 76000 Queretaro, Qro. (Mexico)

    2015-10-15

    Full text: In this work, we evaluated the effect of Cu-dopant concentration in SiO{sub 2} particles on structural and thermoluminescence (Tl) properties, prepared by the sol-gel technique. Tl studies in silica samples containing Cu show an important enhancement of their Tl response when compared with pure silica samples. In the copper doped silica a prominent Tl peak is observed, the glow curve was observed between 70 and 450 degrees C after exposure to beta irradiation. The maximum temperature of the glow peak centered at around 140 degrees C shifts to higher values and the intensity enhancement with increasing Cu content, this glow curve is surely composed of several overlapped individual Tl peaks. Also, the particle size is affected by the concentration of Cu dopant. In the case SiO{sub 2}, only is observed a glow peak centered to 95 degrees C, which is interesting for non-Tl dosimetry of ionizing radiation, which is based in detecting the afterglow response following exposure to radiation. The dose response of SiO{sub 2}:Cu showed a linear behaviour in the interval studied with no saturation evidence until 6.4 kGy, which makes this material suitable and promising for medical, industrial and also space dosimetry applications. (Author)

  12. Investigation of vulcanization of non-crystalline Cu{sub 2}ZnSnS{sub 4} nano-particles

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shih Hsiung [Industrial Technology Research Institute, Hsinchu 31040, Taiwan (China); Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Shih, Chuan Feng, E-mail: cfshih@mail.ncku.edu.tw [Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Pan, Hung Chun; Wang, Yu Yun; Chen, Ho Min; Wu, Chung Shin [Industrial Technology Research Institute, Hsinchu 31040, Taiwan (China)

    2013-10-01

    Non-crystalline Cu{sub 2}ZnSnS{sub 4}(CZTS) nano-particles were fabricated by hydrothermal method. CZTS nano-particles that have different Cu/(Zn + Sn) ratio (0.77, 0.89, 1.02) were separately prepared. The morphology, composition and crystal structure of the as-prepared nano-particles and the vulcanized films were investigated by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffractometry, and Raman spectroscopy. When the temperature and time of vulcanization exceeded 400 °C and 60 min, respectively, the Cu-rich phase (Cu{sub 3}SnS{sub 4}) emerged. Sn lost during vulcanization. CZTS sample with 0.77 Cu content (Cu/(Zn + Sn) = 0.77) showed pure kesterite CZTS without secondary phases when they were vulcanized at 400 °C for 60 min. - Highlights: • Non-crystalline Cu{sub 2}ZnSnS{sub 4} (CZTS) nano-particles were synthesized. • After vulcanizing, the CZTS films showed some voids and grain size of 500 nm. • Cu{sub 3}SnS{sub 4} was obtained when the vulcanization temperature exceeded 500 °C. • Pure Kesterite CZTS was obtained at a vulcanization temperature as low as 400 °C.

  13. Analysis of PM{sub 2.5} particles in atmospheric dust of the MZVM; Analisis de particulas PM{sub 2.5} en polvo atmosferico de la ZMVM

    Energy Technology Data Exchange (ETDEWEB)

    Aldape U, F. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-01-15

    The objectives and scopes of this report are: to determine the places more representative for the installation of four stations of monitoring of small particles to 2.5 micrometers (PM{sub 2.5} ) guided to protect the population's health in the regions indicated by the General Address of Environmental Administration of the Air (DGGM) of the Government of the Federal District (GDF). To select the places to collect PM{sub 2.5} in each one of the regions under study placing each place inside a contiguous cell of 2 x 2 km. To determine the concentration of PM{sub 2.5} in the selected places. To determine the temporary and space behavior of the fine particles in each one of the regions designated in this study. To determine the elementary concentration of some samples of PM{sub 2.5} in the four regions. The execution of this project will contribute to that the installation of the net of monitoring of particles of PM{sub 2.5} is carried out with scientific foundation. (Author)

  14. Spontaneous growth of whiskers from an interlayer of Mo sub 2 C beneath a diamond particle deposited in a combustion-flame

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Katsuyuki; Komatsu, Shojiro; Ishigaki, Takamasa; Matsumoto, Seiichiro; Moriyoshi, Yusuke (National Inst. for Research in Inorganic Materials, Tsukuba, Ibaraki (Japan))

    1992-02-01

    When diamond particles deposited on a molybdenum substrate in a C{sub 2}H{sub -}O{sub 2} combustion-flame were kept for one year in the ambient atmosphere at room temperature, spontaneous whisker growth from an interlayer of Mo{sub 2}C beneath the diamond particles took place. The whiskers were clarified by electron probe micro-analysis (EPMA) and transmission electron microscopy (TEM) in a polycrystal composed of MoO{sub 2}, MoOC, and Mo{sub 2}C. The growth mechanism of them is discussed from two different points of view as follows: One is that the oxidation of an interlayer of Mo{sub 2}C beneath a diamond particle effectively reduces the surface free energy between the interlayer and diamond particle; consequently, the whisker can grow by using a screw dislocation. The other is that the internal stress existing between a diamond particle and an Mo{sub 2}C interlayer provides a very reactive zone where the growth of whisker takes place through the oxidation of Mo{sub 2}C. (orig.).

  15. Magnetic relaxation phenomena and inter-particle interactions in nanosized gamma-Fe sub 2 O sub 3 systems

    CERN Document Server

    Predoi, D; Tronc, E; Nogues, M; Russo, U; Principi, G; Filoti, G

    2003-01-01

    Samples of gamma-Fe sub 2 O sub 3 nano-particles with a mean size of 4.0(3) nm and with different hydration and surfactant degrees were prepared by sol-gel methods. Morphology and structural data were obtained by transmission electron microscopy and x-ray diffraction, whereas the surface effects and hyperfine interactions were analysed mainly by Moessbauer spectroscopy. The relative number of surface iron positions was found to be proportional to the amount of OH sup - and SO sub 4 sup 2 sup - groups on the particle surface, which in turn is strictly dependent on the preparation conditions. Strong relaxation processes versus temperature were evidenced in the analysed systems. New criteria for the evaluation of the blocking temperature via Moessbauer measurements are proposed. The results are in good agreement with blocking temperatures obtained by magnetic measurements. Moreover, it was shown that the inter-particle magnetic interactions decrease with the number of iron surface states.

  16. Applications of Cu{sub 2}O octahedral particles on ITO glass in photocatalytic degradation of dye pollutants under a halogen tungsten lamp

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Wei [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Sun, Fengqiang, E-mail: fqsun@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, South China Normal University (China); Exhibition Base of Production, Study and Research on New Polymer Materials and Postgraduate Students’ Innovation Training of Guangdong Higher Education Institutes (China); Chen, Wei; Zhang, Lihe; Min, Zhilin; Li, Weishan [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China)

    2013-11-15

    Graphical abstract: - Highlights: • Photocatalytic activity of Cu{sub 2}O octahedral microcrystals on ITO glass was studied. • They showed high abilities in degradation of methylene blue in the presence of H{sub 2}O{sub 2}. • H{sub 2}O{sub 2} amount could affect the degradation efficiency. • Such particles could be easily recycled and still kept high activity. • Many dye pollutants and their mixtures could be efficiently degraded. - Abstract: Cu{sub 2}O octahedral microcrystals were prepared on the ITO glass by galvanostatic electrodeposition in CuSO{sub 4} solution with poly(vinylpryrrolidone) as the surfactant. By controlling the electrodeposition time, the microcrystals could be randomly distributed on the ITO glass and separated from each other, resulting in as many as possible (1 1 1) crystalline planes were exposed. Such microcrystals immobilized on ITO glass were employed in photodegradation of dye pollutants in the presence of H{sub 2}O{sub 2} under a 150 W halogen tungsten lamp. The photodegradation of methylene blue was taken as an example to evaluate the photocatalytic activities of the octahedral Cu{sub 2}O microcrystals. Effects of electrodeposition time and H{sub 2}O{sub 2} amount on the degradation efficiency was discussed, giving the optimum conditions and the corresponding degradation mechanism. The catalyst showed high ability in degradation of methylene blue, methyl orange, rhodamine B, eosin B and their mixtures under identical conditions.

  17. Polystyrene bound stationary phase of excellent separation efficiency based on partially sub-2μm silica monolith particles.

    Science.gov (United States)

    Ali, Faiz; Cheong, Won Jo; A L Othman, Zeid A; A L Majid, Abdullah M

    2013-08-16

    Partially sub-2μm porous silica monolith particles have been synthesized by a renovated procedure and modified to polystyrene coated silica particles with excellent separation efficiency when used as chromatographic media. In the procedure of preparing silica monolith particles in this study, subtle control of formulation of the reaction mixture and multi-step heating followed by calcination, without any washing and sieving process, enabled formation of silica particles characterized by proper particle and pore size distribution for high separation efficiency. 3-Chloropropyl trimethoxysilane was used as the halogen terminal spacer to combine the initiator to silica particles. Uniform and thin coating of polystyrene layer on initiator attached silica particles was formed via reversible addition-fragmentation chain transfer (RAFT) polymerization. Micro-columns (1.0mm ID and 300mm length) were packed with the resultant phase and their chromatographic performance was elucidated by HPLC. A mobile phase of 60/40 (v/v) acetonitrile/water containing 0.1% TFA and a flow rate of 15μL/min were found to be the optimized conditions leading to number of theoretical plates close to 50,000 (165,000m(-1)). This is the very first study to get such highly efficient HPLC columns using a silica monolith particulate stationary phase. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Quantitative study of particle size distribution in an in-situ grown Al–TiB{sub 2} composite by synchrotron X-ray diffraction and electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Y. [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Chen, Z., E-mail: zhe.chen@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Borbély, A. [SMS Materials Center, LGF-CNRS UMR 5307, Ecole des Mines de Saint Etienne, 158, Cours Fauriel, 42023 Saint Etienne (France); Ji, G. [Unité Matériaux et Transformations, CNRS UMR 8207, Université Lille 1, Villeneuve d' Ascq 59655 (France); Zhong, S.Y. [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Schryvers, D. [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Ji, V. [ICMMO/LEMHE, UMR CNRS 8182, Université Paris-Sud 11, Orsay Cedex 91405, France. (France); Wang, H.W. [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-04-15

    Synchrotron X-ray diffraction and transmission electron microscopy (TEM) were applied to quantitatively characterize the average particle size and size distribution of free-standing TiB{sub 2} particles and TiB{sub 2} particles in an in-situ grown Al–TiB{sub 2} composite. The detailed evaluations were carried out by X-ray line profile analysis using the restricted moment method and multiple whole profile fitting procedure (MWP). Both numerical methods indicate that the formed TiB{sub 2} particles are well crystallized and free of crystal defects. The average particle size determined from different Bragg reflections by the restricted moment method ranges between 25 and 55 nm, where the smallest particle size is determined using the 110 reflection suggesting the highest lateral-growth velocity of (110) facets. The MWP method has shown that the in-situ grown TiB{sub 2} particles have a very low dislocation density (~ 10{sup 11} m{sup −} {sup 2}) and their size distribution can be described by a log-normal distribution. Good agreement was found between the results obtained from the restricted moment and MWP methods, which was further confirmed by TEM. - Highlights: • Accurate quantitative characterization of in-situ grown T{sub i}B{sub 2} particles has been achieved. • Particle size anisotropy was revealed indicating 110 facets being largest during T{sub i}B{sub 2} growth. • A wide size distribution was observed for T{sub i}B{sub 2} particles with a dominant size smaller than 100 nm.

  19. Sub 2-μm macroporous silica particles derivatized for enhanced lectin affinity enrichment of glycoproteins.

    Science.gov (United States)

    Mann, Benjamin F; Mann, Amanda K P; Skrabalak, Sara E; Novotny, Milos V

    2013-02-05

    A new, mechanically stable silica microparticle with macrosized internal pores (1.6 μm particles with 100 nm pores) has been developed for chromatography. The particles are characterized by an extensive network of interconnected macropores with a high intraparticle void volume, as observed by transmission electron microscopy (TEM). They are synthesized by an aerosol assembly technique called ultrasonic spray pyrolysis (USP). The particles have a high surface area for a macroporous material, ∼200 m(2)/g, making them suitable for large biomolecular separations. To demonstrate their potential for bioseparations, they have been functionalized with lectins for affinity enrichment of glycoproteins. The material was derivatized with two lectins, Concanavalin A (Con A) and Aleuria aurantia lectin (AAL), and binding properties were tested with standard glycoproteins. The columns exhibited excellent binding capacities for microaffinity enrichment: Con A was able to bind 75 μg of a standard glycoprotein in a 50 × 1 mm column. Following initial tests, the lectin microcolumns were utilized for enrichment of glycoproteins from 1 μL volumes of blood serum samples, performed in triplicate for each lectin. The enriched serum fractions were subjected to side-by-side glycomic and glycoproteomic profiling analyses with mass spectrometry to show that the new particles offer excellent sensitivity for microscale analyses of precious biological sample materials. The unique combination of the macroporous architecture and small particle diameter suggests the material may have advantages for conventional modes of chromatographic separation of macromolecules in an ultra-high-pressure liquid chromatography (UHPLC) format.

  20. Antibacterial performance of nano polypropylene filter media containing nano-TiO{sub 2} and clay particles

    Energy Technology Data Exchange (ETDEWEB)

    Shafiee, Sara; Zarrebini, Mohammad; Naghashzargar, Elham, E-mail: e.naghashzargar@tx.iut.ac.ir; Semnani, Dariush, E-mail: d-semnani@cc.iut.ac.ir [Isfahan University of Technology, Department of Textile Engineering (Iran, Islamic Republic of)

    2015-10-15

    Disinfection and elimination of pathogenic microorganisms from liquid can be achieved by filtration process using antibacterial filter media. The advent of nanotechnology has facilitated the introduction of membranes consisting of nano-fiber in filtration operations. The melt electro-spun fibers due to their extremely small diameters are used in the production of this particular filtration medium. In this work, antibacterial polypropylene filter medium containing clay particles and nano-TiO{sub 2} were made using melt electro-spun technology. Antibacterial performance of polypropylene nano-filters was evaluated using E. coli bacteria. Additionally, filtration efficiency of the samples in terms fiber diameter, filter porosity, and fiber distribution using image processing technique was determined. Air permeability and dust aerosol tests were conducted to establish the suitability of the samples as a filter medium. It was concluded that as far as antibacterial property is concerned, nano-fibers filter media containing clay particles are preferential to similar media containing TiO{sub 2} nanoparticles.

  1. Influence of Pt particles on the porosity of Al{sub 2}O{sub 3} coating prepared by cathode plasma electrolytic deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng [Beijing Key Laboratory for Corrosion, Erosion and Surface Technology, University of Science and Technology Beijing, 100083, Beijing (China); Research Institute of Aerospace Special Materials and Processing Technology, 100074, Beijing (China); He, Yedong, E-mail: htgroup@mater.ustb.edu.cn [Beijing Key Laboratory for Corrosion, Erosion and Surface Technology, University of Science and Technology Beijing, 100083, Beijing (China); Zhang, Jin [Beijing Key Laboratory for Corrosion, Erosion and Surface Technology, University of Science and Technology Beijing, 100083, Beijing (China)

    2016-12-01

    Porous Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-Pt coatings were successfully prepared on the Ni-based alloy by cathode plasma electrolytic deposition. It is found that the porosity of coatings can be reduced obviously by Pt particles co-deposited with Al{sub 2}O{sub 3}. This phenomenon can be attributed to that the mechanism of plasma discharge is changed in such CPED. As the Pt particles are dispersed in the Al{sub 2}O{sub 3} coating, the electron avalanche is difficult to occur. So, the breakdown takes place in the Al{sub 2}O{sub 3}-Pt coating difficultly, the destructive effect of the breakdown will therefore be decreased, and the porosity of Al{sub 2}O{sub 3} coating can be reduced which has been verified by the results of surface morphologies of the coatings. - Highlights: • The Al{sub 2}O{sub 3}-Pt coatings were prepared on Ni-based alloys by CPED. • The porosity of coating is reduced obviously by Pt particles dispersed with Al{sub 2}O{sub 3}. • The related mechanisms of plasma discharge in CPED were discussed.

  2. CO{sub 2} capture with calcined dolomite: the effect of sorbent particle size

    Energy Technology Data Exchange (ETDEWEB)

    Stendardo, Stefano [Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Rome (Italy); Di Felice, Luca; Gallucci, Katia; Foscolo, Pier Ugo [University of L' Aquila, L' Aquila (Italy)

    2011-09-15

    This investigation is set in the more comprehensive study of an innovative fluidized bed reformer configuration for producing hydrogen from either biomass/coal syngas or natural gas, in which capture of carbon dioxide by-product occurs in parallel with steam reforming and water-gas shift reactions. Reported here are experimental data of carbon dioxide absorption by particles of calcined dolomite included in a bed of otherwise inert material; the bed, initially fluidized by nitrogen, was subjected to a step concentration input of carbon dioxide and the sorption kinetics was obtained from the outlet response of the entire system. The influence of dolomite particle size was investigated - from 98 to 1,550 {mu}m - and a previously developed grain model was used to relate the observed effect of particle diameter to the complex mechanism of carbon dioxide capture in a solid sorbent. The results show that pore shrinking effects during the carbon dioxide capture process become increasingly more significant as the particle size is increased. (orig.)

  3. Investigations of mussel-inspired polydopamine deposition on WC and Al{sub 2}O{sub 3} particles: The influence of particle size and material

    Energy Technology Data Exchange (ETDEWEB)

    Mondin, Giovanni, E-mail: giovanni.mondin@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Haft, Marcel, E-mail: m.haft@ifw-dresden.de [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Institute for Solid State Research, Helmholtzstr. 20, 01069 Dresden (Germany); Wisser, Florian M., E-mail: florian.wisser@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Leifert, Annika, E-mail: annika.leifert@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Mohamed-Noriega, Nasser, E-mail: nasser.mohamed-noriega@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Dörfler, Susanne, E-mail: susanne.doerfler@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Hampel, Silke, E-mail: s.hampel@ifw-dresden.de [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Institute for Solid State Research, Helmholtzstr. 20, 01069 Dresden (Germany); Grothe, Julia, E-mail: stefan.kaskel@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Kaskel, Stefan, E-mail: julia.grothe@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany)

    2014-12-15

    Polydopamine, formed by oxidation of dopamine, is a bioinspired polymer developed for multifunctional coatings by Lee et al. in 2007 by drawing inspiration from the adhesive proteins found in mussels. Due to their high versatility and substrate-independence, polydopamine coatings are gaining considerable attention in a plethora of research fields, particularly in the coating of particles, but systematic investigations of the polydopamine coating process are lacking in the literature. In this study, we explore by TEM and thermogravimetric analysis the polydopamine coating process on alumina microparticles, tungsten carbide microparticles and tungsten carbide nanoparticles. By choosing two substrates with similar size but different material (Al{sub 2}O{sub 3} and WC), as well as two substrates of the same material but different size (WC micro- and nanoparticles) we investigate the effects of both substrate material and substrate size, in order to gain some insights into the polydopamine particle coating process. As opposed to what is generally assumed in the literature, we found that the polydopamine coating thicknesses on particles, as well as the thickness growing trend, depend on the particles size and material. In particular, after 24 h of polymerization time the polydopamine coatings reached a thickness of 65 ± 10 nm in the case of Al{sub 2}O{sub 3} microparticles, 18 ± 4 nm in the case of WC microparticles and 33 ± 6 nm in the case of WC nanoparticles. - Highlights: • The coating of different particles with polydopamine was systematically investigated. • Al{sub 2}O{sub 3} microparticles and WC microparticles and nanoparticles were investigated. • The thickness of the polydopamine coating depends on the particle size. • The thickness of the polydopamine coating depends on the particle material.

  4. Effect of oxidizer to fuel molar ratio on particle size and DC conductivity of CeO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Harish, B. M.; Rajeeva, M. P.; Naveen, C. S.; Chaturmukha, V. S.; Avinash, B. S.; Jayanna, H. S.; Lamani, Ashok R., E-mail: ashok1571972@gmail.com [Department of P.G. studies and Research in Physics, Kuvempu University, Jnanasahyadri, Shankarghatta, Shimoga, Karnataka, India-577451. (India)

    2016-05-06

    Cerium oxide nanoparticles were synthesized by solution combustion method with varying the oxidizer (cerium nitrate hexa hydrate) to fuel (Glycine) molar ratio. The prepared samples were characterized by UV-visible spectrometer, X-ray diffractometer (XRD), Scanning electron microscope (SEM) and Energy dispersive X-Ray analysis (EDAX). XRD pattern reveals the formation of cubic fluorite structure of CeO{sub 2}. It was observed that finest crystallites were found at extreme fuel-deficient condition and it is good enough to produce favorable powder characteristics. The average crystallite size was found to be 14.46 nm to 21.57 nm. The temperature dependent dc conductivity was carried out using Keithley source meter between the temperature range from 300 K to 573 K. From this study it was found that the conductivity increases with increase of temperature due to semiconducting behavior of CeO{sub 2} and it decreases with particle size due to increase in the energy band gap.

  5. In-line monitoring of effluents from high-temperature gas-cooled reactor fuel particle preparation processes by mass spectrometry. [UO/sub 2/; UC/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.A.; Constanzo, D.A.; Stinton, D.P.; Carpenter, J.A. Jr.; Rainey, W.T.; Canada, D.C.; Carter, J.A.

    1977-06-01

    The carbonization, conversion, and coating processes in the manufacture of high-temperature gas-cooled reactor fuel particles have been studied with the use of a time-of-flight mass spectrometer. Noncondensable effluents from these fluidized-bed processes have been monitored continuously from the beginning to the end of the process. The processes monitored are these: uranium-loaded ion exchange resin carbonization, the carbothermic reduction of UO/sub 2/ to UC/sub 2/, buffer and low-temperature isotropic pyrocarbon coatings of fuel kernels, SiC coating of the kernels, and high-temperature particle annealing. Changes in concentrations of significant molecules with time and temperature have been useful in the interpretation of reaction mechanisms and optimization of process procedures.

  6. Electrochemical insertion and extraction of lithium-ion at nano-sized LiMn{sub 2}O{sub 4} particles prepared by a spray pyrolysis method

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Takayuki; Okada, Shigeto; Yamaki, Jun-ichi [Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen, Kasuga 816-8580 (Japan); Yahiro, Tsutomu [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga 816-8580 (Japan)

    2008-11-15

    Nano-sized LiMn{sub 2}O{sub 4} particles were prepared at 1023 K by electrospray pyrolysis in which they were directly deposited on a Pt substrate in gas phase. Cyclic voltammetry gave very sharp and symmetrical redox peaks at ca. 4.0 and 4.1 V vs. Li/Li{sup +} owing to the insertion and extraction of lithium-ion at LiMn{sub 2}O{sub 4}. However, the redox peaks broadened and their peak separation in an electrode potential increased when aggregated nano-sized LiMn{sub 2}O{sub 4} particles were used. In Nyquist plots, a semi-circle due to lithium-ion transfer resistance appeared at potentials above 3.90 V. The values of the lithium-ion transfer resistances were small for dispersed nano-sized LiMn{sub 2}O{sub 4} particles. On the other hand, the lithium-ion transfer resistances increased and the Warburg impedance became obvious as the nano-sized LiMn{sub 2}O{sub 4} particles aggregated. These results clearly indicate that the apparent rapid diffusion of lithium-ion can be attained using well-dispersed nano-sized particles of electroactive materials. (author)

  7. Modifying magnetic properties and dispersity of few-layer MoS{sub 2} particles by 3d metal carboxylate complexes

    Energy Technology Data Exchange (ETDEWEB)

    Golub, Alexandre S., E-mail: golub@ineos.ac.ru [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991 Moscow (Russian Federation); Lenenko, Natalia D. [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991 Moscow (Russian Federation); Zaikovskii, Vladimir I. [Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Lavrentieva Ave. 5, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova St. 2, 630090 Novosibirsk (Russian Federation); Efimov, Nikolay N.; Dobrokhotova, Zhanna V.; Baranchikov, Alexander E.; Kiskin, Mikhail A. [N.S. Kurnakov Institute of General and Inorganic Chemistry, Leninskii Prosp. 31, 119991 Moscow (Russian Federation); Eremenko, Igor L. [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991 Moscow (Russian Federation); N.S. Kurnakov Institute of General and Inorganic Chemistry, Leninskii Prosp. 31, 119991 Moscow (Russian Federation)

    2016-11-01

    The interaction of MoS{sub 2} sheets produced by chemical exfoliation of LiMoS{sub 2} in liquid media with trinuclear metal carboxylate complexes of the general formula [M{sub 3}(O{sub 2}CR){sub 6}L{sub 3}]{sup n+} (M = Fe, Co; R = CH{sub 3}, C(CH{sub 3}){sub 3}, CH{sub 2}N{sup +}(CH{sub 3}){sub 3}; L = H{sub 2}O or pyridine) was studied. The composition, structure and dispersity of the obtained materials as well as the distribution of magnetically active metal cations within their particles were analyzed on the basis of PXRD, SEM, TEM, HAADF-STEM, TGA-MS and magnetic measurements data. The interaction process was found to result in the displacement of the important part of carboxylate ligands from coordination environment of metal ions and formation of metal oxide-like nanoclusters. These nanoclusters are distributed within the surface of MoS{sub 2} sheet packets of the thickness of 4–6 nm, which are formed due to restacking of exfoliated MoS{sub 2}. The metal complexes strongly influence sheet restacking, leading to a significantly lower (up to ∼ 1.5 times) thickness of the sulfide packets than in their absence. The metal atoms constituting oxide nanoclusters exhibit strong antiferromagnetic interactions. - Highlights: • MoS{sub 2} sheets interaction with Fe(Co) carboxylate complexes leads to deposition of metal oxide-like clusters on these sheets. • MoS{sub 2} sheet stacking in the presence of metal complexes yields 4–6 nm thick particles. • The metal atoms constituting deposited nanoclusters exhibit strong antiferromagnetic interactions.

  8. Interface-specific reorientation of embedded tetragonal ZrO{sub 2} particles in Ni{sub 1-x}O polycrystals

    Energy Technology Data Exchange (ETDEWEB)

    Li, M.-Y. [Institute of Materials Science and Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Shen Pouyan [Institute of Materials Science and Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan (China)]. E-mail: pshen@mail.nsysu.edu.tw

    2005-05-25

    ZrO{sub 2}/Ni{sub 1-x}O (1:9 in molar ratio) composites were sintered and then annealed at 1650deg. C for 24 and 100h in air to study Ni{sub 1-x}O surface-controlled reorientation of the tetragonal (t-) ZrO{sub 2} particles, which transformed into monoclinic (m-) twin variants upon cooling. Transmission electron microscopy indicated that the ZrO{sub 2} particles fell into three topotaxial relationships with respect to the host Ni{sub 1-x}O grains: (1) parallel topotaxy (2) ''eutectic'' topotaxy, i.e. [100]{sub Z}//[111]{sub N}, [010]{sub Z}//[01-bar 1]{sub N} and (3) ''occasional'' topotaxy [100]{sub Z}//[111]{sub N}, [011-bar ]{sub Z}//[01-bar 1]{sub N}. The parallel topotaxy has a beneficial low energy for the family of {l_brace}100{r_brace}{sub Z,N} and {l_brace}111{r_brace}{sub Z,N} interfaces. The change from the occasional topotaxy to an energetically more favorable eutectic topotaxy was likely achieved by a rotation of the ZrO{sub 2} particles over a specific (100){sub Z}/(111){sub N} interface. Brownian-type rotation is probable for the embedded t-ZrO{sub 2} particles in terms of anchorage release at the interphase interface with the Ni{sub 1-x}O host. Detachment or bypassing of grain boundaries could also cause reorientation and shape change of intergranular ZrO{sub 2} particles.

  9. Influence of clay particles on Al{sub 2}O{sub 3} and TiO{sub 2} nanoparticles transport and retention through limestone porous media: measurements and mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Bayat, Ali Esfandyari, E-mail: ali.esfandiari.bayat@gmail.com; Junin, Radzuan [Universiti Teknologi Malaysia, Department of Petroleum Engineering, Faculty of Petroleum and Renewable Energy Engineering (Malaysia); Mohsin, Rahmat [Universiti Teknologi Malaysia, UTM-MPRC Institute for Oil and Gas, N29A, Lengkuk Suria (Malaysia); Hokmabadi, Mehrdad [Universiti Teknologi Malaysia, Department of Petroleum Engineering, Faculty of Petroleum and Renewable Energy Engineering (Malaysia); Shamshirband, Shahaboddin [University of Malaya, Department of Computer System and Information Technology, Faculty of Computer System and Information Technology (Malaysia)

    2015-05-15

    Utilization of nanoparticles (NPs) for a broad range of applications has caused considerable quantities of these materials to be released into the environment. Issues of how and where the NPs are distributed into the subsurface aquatic environments are questions for those in environmental engineering. This study investigated the influence of three abundant clay minerals namely kaolinite, montmorillonite, and illite in the subsurface natural aquatic systems on the transport and retention of aluminum oxide (Al{sub 2}O{sub 3}, 40 nm) and titanium dioxide (TiO{sub 2}, 10–30 nm) NPs through saturated limestone porous media. The clay concentrations in porous media were set at 2 and 4 vol% of the holder capacity. Breakthrough curves in the columns outlets were measured using a UV–Vis spectrophotometer. It was found that the maximum NPs recoveries were obtained when there was no clay particle in the porous medium. On the other hand, increase in concentration of clay particles has resulted in the NPs recoveries being significantly declined. Due to fibrous structure of illite, it was found to be more effective for NPs retention in comparison to montmorillonite and kaolinite. Overall, the position of clay particles in the porous media pores and their morphologies were found to be two main reasons for increase of NPs retention in porous media.

  10. The NO and N{sub 2}O formation mechanism under circulating fluidized bed combustor conditions: from the single particle to the pilot-scale

    Energy Technology Data Exchange (ETDEWEB)

    Winter, F.; Loeffler, G.; Wartha, C.; Hofbauer, H. [Vienna University of Technology, Institute of Chemical Engineering, (Austria); Preto, F.; Anthony, E. J. [Natural Resources Canada, CANMET, Ottawa, ON (Canada)

    1999-04-01

    The mechanism of NO and N{sub 2}O formation is studied, starting with a single fuel particle burning under well-defined conditions up to a pilot-scale circulating fluidized bed combustor (CFBC). The single particle test was focused on the formation chemistry, and a single particle NO/N{sub 2}O formation model was developed and tested and incorporated into a CFBC NO/N{sub 2}O emission model. The fuel, petroleum coke, was the same in all tests and care has been taken to obtain chemical similarity between the different units, i.e. a formation rate unit, a laboratory-scale and a pilot-scale CFBC. To thoroughly test the modeled NO/N{sub 2}O mechanism and to confirm that chemical similarity exists between the different units, the iodine addition method has been used in the single particle tests, in the batch tests, in the laboratory-scale and the pilot-scale CFBC tests. 52 refs., 2 tabs., 5 figs.

  11. Shape and catalytic mechanism of RuO{sub 2} particles at CO oxidation reaction conditions. First-principles based multi-scale modeling

    Energy Technology Data Exchange (ETDEWEB)

    Reuter, Karsten [TU Muenchen (Germany). Lehrstuhl fuer Theoretische Chemie

    2016-11-01

    For model catalyst studies on low-index single-crystal surfaces close agreement between detailed measurements and quantitative microkinetic modeling can increasingly be achieved. However, for 'real' catalyst particles, such structure-morphology-activity relationships are only scarcely established. This is prototypically reflected by the situation for RuO{sub 2}, as a most active catalyst for CO oxidation. Here, existing first-principles kinetic modeling is restricted to just one facet, namely the RuO{sub 2}(110) surface, which is not able to fully account for activity data obtained from polycrystalline RuO{sub 2} powder catalysts. The overarching objective of this project was correspondingly to close this gap and demonstrate that similarly close agreement as for individual single-crystal model catalysts can also be achieved for catalyst particles. Specifically, we addressed experiments where an intact RuO{sub 2} bulk structure is conserved, and establish the atomic-scale structure and reactivity of other RuO{sub 2} low-index facets under the gas-phase conditions characteristic for catalytic CO oxidation.

  12. Electrochemically deposited Cu{sub 2}O cubic particles on boron doped diamond substrate as efficient photocathode for solar hydrogen generation

    Energy Technology Data Exchange (ETDEWEB)

    Mavrokefalos, Christos K. [Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, England (United Kingdom); Hasan, Maksudul, E-mail: maksudul.hasan@chem.ox.ac.uk [Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, England (United Kingdom); Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland); Rohan, James F. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland); Compton, Richard G. [Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, England (United Kingdom); Foord, John S., E-mail: john.foord@chem.ox.ac.uk [Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, England (United Kingdom)

    2017-06-30

    Highlights: • Fabrication of low-cost photocathode by electrochemical method is described. • Boron-doped diamond is presented as catalyst support. • NiO nanoparticles on Cu{sub 2}O surface enhances photocurrent and electrode stability. • Synergy of metallic interaction between Cu and Ni leads to high efficiency. - Abstract: Herein, we report a novel photocathode for the water splitting reaction. The electrochemical deposition of Cu{sub 2}O particles on boron doped diamond (BDD) electrodes and the subsequent decoration with NiO nanoparticles by a dip coating method to act as co-catalyst for hydrogen evolution reaction is described. The morphology analysis by scanning electron microscope (SEM) revealed that Cu{sub 2}O particles are cubic and decorated sporadically with NiO nanoparticles. X-ray photoelectron spectroscopy (XPS) confirmed the electronic interaction at the interface between Cu{sub 2}O and NiO through a binding energy shift of the main Cu 2p peak. The photoelectrochemical (PEC) performance of NiO-Cu{sub 2}O/BDD showed a much higher current density (−0.33 mA/cm{sup 2}) and photoconversion efficiency (0.28%) compared to the unmodified Cu{sub 2}O/BDD electrode, which are only −0.12 mA/cm{sup 2} and 0.06%, respectively. The enhancement in PEC performance is attributable to the synergy of NiO as an electron conduction mediator leading to the enhanced charge separation and transfer to the reaction interface for hydrogen evolution as evidenced by electrochemical impedance spectroscopy (EIS) and charge carrier density calculation. Stability tests showed that the NiO nanoparticles loading content on Cu{sub 2}O surface is a crucial parameter in this regard.

  13. Effect of ultrasonication on particle size and magnetic properties of polyaniline NiCoFe{sub 2}O{sub 4} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Chitra, Palanisamy [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Muthusamy, Athianna, E-mail: muthusrkv@gmail.com [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Jayaprakash, Rajan; Ranjith Kumar, Easwaran [Nanotechnology Laboratory, Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India)

    2014-10-01

    Polyaniline nanocomposites (PANI/NiCoFe{sub 2}O{sub 4}) have been synthesized by in-situ chemical polymerization of aniline in the presence of NiCoFe{sub 2}O{sub 4} nanoparticles (20%, 10% w/w of fine powders) with and without ultrasonic treatment. The average particle size of NiCoFe{sub 2}O{sub 4} synthesized by auto-combustion method is 32 nm. The particle size of the PANI nanocomposites synthesized vary in the range of 24–41 nm. The structure, morphology and magnetic properties of PANI and nanocomposites are characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM) and Vibrating sample magnetometer (VSM). The nanocomposites are further characterized by Fourier transform infrared spectra (FTIR), Thermogravimetric analysis (TGA) and second harmonic generation (SHG) activity. The nature of PANI/NiCoFe{sub 2}O{sub 4} is visualized through the SEM and TEM images and also the presence of NiCoFe{sub 2}O{sub 4} on PANI is confirmed with FTIR spectra. XRD patterns of NiCoFe{sub 2}O{sub 4} have higher intense diffraction peaks than PANI/NiCoFe{sub 2}O{sub 4} nanocomposites. Hysteresis measurements revealed that the saturation magnetization (M{sub s}) increases with increase in ferrite content whereas, coercivity decreases. Ferromagnetic nature of PANI/NiCoFe{sub 2}O{sub 4} nanocomposites are confirmed by VSM. FTIR investigation indicates that the main absorption peaks corresponding to the spinel structure appeared at around 600 cm{sup −1}; it is due to the NiCoFe{sub 2}O{sub 4} tetrahedral and octahedral stretching vibrations. - Highlights: • An auto-combustion method support to prepare less size of particles. • Nature of the samples was influenced by sonication. • The longer time of ultrasonic treatment in increased viscosity of polymer mixture.

  14. Depolarization of the 4{sup 1}D{sub 2} state of a helium atom by charged particles in beam plasma discharge

    Energy Technology Data Exchange (ETDEWEB)

    Kazantsev, S.A.; Luchinkina, V.V.; Mezentsev, A.P.; Mustafaev, A.S.; Rebane, V.N.; Rys, A.G.; Stepanov, Yu.L. [St. Petersburg (Russian Federation)

    1994-06-01

    Depolarization of the 4{sup 1}D{sub 2}-2{sup 1}P{sub 1} spectra line of He atoms caused by collisions with charged particles in beam plasma discharge is investigated both experimentally and theoretically. A comparison is made between the values of the rate constant for the collisional breakdown of alignment of helium atoms in the 4{sup 1}D{sub 2} state calculated from the theory of collisional relaxation of atomic polarization moments and determined from the experimentally observed broadening of the Hanle signal contour with the increase of the beam discharge current. 23 refs., 6 figs.

  15. Surface doping for photocatalytic purposes: relations between particle size, surface modifications, and photoactivity of SnO{sub 2}:Zn{sup 2+} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Li Liping; Liu Junjie; Su Yiguo; Li Guangshe; Chen Xiaobo; Qiu Xiaoqing; Yan Tingjiang [State Key Structural Chemistry Laboratory and Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China)], E-mail: guangshe@fjirsm.ac.cn

    2009-04-15

    Highly crystalline SnO{sub 2} nanocrystals with and without Zn{sup 2+} doping were directly prepared by a solvothermal method. By systematic characterizations using x-ray diffraction, transmission electron microscopy, infrared spectra, and UV-vis spectra, it is demonstrated that all samples crystallized in a single phase of rutile structure, and that upon Zn{sup 2+} doping particle sizes closer to the exciton Bohr radius (2.7 nm) of SnO{sub 2} were achieved, while the particle size of SnO{sub 2} nanoparticles was as large as about 12 nm without Zn{sup 2+} doping. The smaller particle sizes for Zn{sup 2+} doped nanoparticles had led to a lattice expansion, a blue-shift of the surface phonon mode for the anti-symmetric Sn-O stretching vibration, and a significantly narrowed band-gap energy, opposite to what is theoretically predicted by the quantum size effect. The photocatalytic activity of the doped samples is measured by monitoring the degradation of methylene blue dye in an aqueous solution under UV-radiation exposure. It is found that Zn{sup 2+} doped SnO{sub 2} showed excellent activity toward photodegradation of methylene blue solution under UV light irradiation. These observations were interpreted in terms of the Zn{sup 2+} doping at the surface sites of SnO{sub 2} nanoparticles and the relevant defects that have increased the surface active sites and moreover improved the ratio of surface charge carrier transfer rate to the electron-hole recombination rate. These results illustrate the potential of rationally modifying the particle size and surface defect characteristics for novel semiconductor oxide photocatalysts.

  16. NOx and N{sub 2}O formation mechanisms - A detailed chemical kinetic modeling study on a single fuel particle in a laboratory-scale fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Loffler, G.; Andahazy, D.; Wartha, C.; Winter, F.; Hofbauer, H. [Vienna University of Technology, Vienna (Austria). Inst. of Chemical Engineering Fuel Technology & Environmental Technology

    2001-09-01

    NOx (i.e., NO and NO{sub 2}) and N{sub 2}O are known as harmful pollutants. In fluidized bed combustion these are formed from the nitrogen in the fuel. To develop effective primary measures to reduce the emissions, more knowledge on the mechanism of formation and destruction ongoing in fluidized beds has to be obtained. In this work, a detailed chemistry model is combined with a two-phase model for a stationary fluidized bed to calculate the emissions of a single fuel particle in a laboratory-scale stationary fluidized bed. The single particle model consists of a simple model for the H{sub 2}O release during drying, a model for the volatiles composition, and a model for the nitrogen chemistry during char combustion. The detailed reaction mechanism consists of a homogeneous part, heterogeneously catalyzed reactions on the bed material, and radical recombination reactions on the solids' surface. The results confirm that devolatilization and char combustion are of nearly equal importance for NO and N{sub 2}O formation. During devolatilization, NO is formed from HCN and NH{sub 3}, while N{sub 2}O is formed almost exclusively from HCN. During char combustion, NO is mostly formed by heterogeneous oxidation of char nitrogen, while N{sub 2}O is formed from homogeneous oxidation of HCN. On the other hand, there is also a back coupling of NO on the homogeneous burnout of the carbon containing species, by sensitizing the oxidation of CH{sub 4}.

  17. Comparative study of nano-sized particles CoFe{sub 2}O{sub 4} effects on superconducting properties of Y-123 and Y-358

    Energy Technology Data Exchange (ETDEWEB)

    Slimani, Y.; Hannachi, E.; Ben Salem, M.K.; Hamrita, A. [Laboratory of Physics of Materials-Structures and Properties, Department of Physics, Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna (Tunisia); Varilci, A. [Faculty of Arts and Sciences, Department of Physics, Abant Izzet Baysal University, 14280 Bolu (Turkey); Dachraoui, W. [CINaM-CNRS, Luminy Campus, 13288 Marseille (France); Ben Salem, M., E-mail: salemwiem2005@yahoo.fr [Laboratory of Physics of Materials-Structures and Properties, Department of Physics, Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna (Tunisia); Ben Azzouz, F. [Laboratory of Physics of Materials-Structures and Properties, Department of Physics, Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna (Tunisia); College of Sciences-Girls, Department of Physics, University of Dammam (Saudi Arabia)

    2014-10-01

    The effects of nano-sized CoFe{sub 2}O{sub 4} particles (10 nm) addition on the structural and the normal state resistivity of YBa{sub 2}Cu{sub 3}O{sub 7} (noted Y-123) and Y{sub 3}Ba{sub 5}Cu{sub 8}O{sub 18} (noted Y-358) polycrystalline were systematically studied. Samples were synthesized in oxygen atmosphere using a standard solid state reaction technique by adding CoFe{sub 2}O{sub 4} up to 2 wt%. Phases, microstructure and superconductivity have been systematically investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrical measurements ρ(T). XRD results reveal that the lattice parameters change for both Y-123 and Y-358 phases. SEM observations reveal that the grain size is reduced with increasing the content of CoFe{sub 2}O{sub 4}. The measurements for the resistivity dependence of temperature show that the depression in superconducting temperature is more pronounced for CoFe{sub 2}O{sub 4} addition in Y-358 compound than in Y-123 one. These results may be attributed to the existence of much more disorder due to a greater number of Cu sites to be substituted by Fe and Co in Y-358 compared to Y-123.

  18. CO{sub 2} AND SO{sub 2} CAPTURE CAPABILITY OF TWO GREEK LIMESTONES UNDER FLUIDIZED BED COMBUSTION CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    P. Basinas [Chemical Process Engineering Laboratory, Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki (Greece); P. Grammelis [Institute of Solid Fuels Technology and Applications / Centre for Research and Technology Hellas, Ptolemais (Greece); J. R. Grace [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver (Canada); C. J. Lim; G. Skodras; E. Kakaras; G. P. Sakellaropoulos

    2008-09-30

    CO2 removal from flue gas streams is a key-factor to reduce greenhouse gas emissions released from combustion systems. Ca-based sorbents constitute an attractive option for CO{sub 2} capture due to their potential for regeneration and the possibility of simultaneous SO{sub 2} capture. However, the decay in the sorbents capture capability after a number of cycles constitutes a problem to the extensive application of the technology. Hence improving sorbent reversibility is imperative to make the technology economically attractive. In the present study, two Greek limestones, from the Megalopolis and Florina areas, were used to capture CO{sub 2} and SO{sub 2}. The regeneration ability and the decay of both limestone samples were investigated through sorption--calcination cycles in a thermogravimetric analyser operated at ambient pressure. The effects of the sorption time (3, 8 and 30 min), reaction temperature (750 and 850 C) and particle size (38-53, 150-250 and 500-800 {micro}m) on the sorbent performance were examined. The two limestones demonstrated similar CO{sub 2} capture capability. The Florina limestone decayed less after a specific number of cycles. When the particle size of the samples increased and when the carbonation temperature was reduced, less CO{sub 2} capture was observed for both samples. The presence of SO{sub 2} inhibited the sorption ability of both limestones. Florina limestone had a higher sorption ability and lower decay when CO{sub 2} and SO{sub 2} were present simultaneously.

  19. In-situ laser spectroscopy of CO, CH{sub 4}, and H{sub 2}O in a particle laden laboratory-scale fluidized bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    Lackner, M.; Totschnig, G.; Loeffler, G.; Hofbauer, H.; Winter, F. [Vienna University of Technology, Vienna (Austria). Inst. of Chemical Engineering

    2002-07-01

    The pyrolysis, devolatilization and char combustion of bituminous coal and biomass (beechwood, firewood) were investigated in a laboratory-scale fluidized bed combustor by tunable diode laser spectroscopy. Individual fuel particles were suspended in the freeboard of the unit. The bed temperature was 800{degree}C, the oxygen partial pressure 0 to 20 kPa. Two Fabry Perot type tunable near infrared diode lasers were deployed for quantitative in-situ species concentration measurement. CH{sub 4} and CO were measured simultaneously during devolatilization and char combustion in-situ 10 mm above the surface of the fuel particles as well as H{sub 2}O using laser spectroscopy. Sand particles were passing the probing laser beam path. Besides the resonant absorption of the laser light by CO, CH{sub 4} and H{sub 2}O severe and strongly transient non-resonant attenuation by partial blocking of the beam and beam steering effects occurred. By wavelength tuning the two laser sources, special concentrations could be determined. The measured absorbances had to be corrected for the real temperature measured at the position of the probing laser beam. In addition, CO, CO{sub 2} and O{sub 2} were determined ex-situ by conventional methods. A spatial profile inside the FBC of major species was calculated using a chemical kinetics program for a single fuel particle in a plug flow reactor geometry. The results were compared to the experimental findings. Good agreement was found. Tunable diode laser spectroscopy was found to be an apt method of determining quantitative species concentrations of multiple gases in a high temperature multi phase environment. 14 refs., 9 figs., 1 tab.

  20. Nanocrystalline Cs{sub x}WO{sub 3} particles: Effects of N{sub 2} annealing on microstructure and near-infrared shielding characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jing-Xiao, E-mail: drliu-shi@dlpu.edu.cn [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Institute of Multidisciplinary Research for Advanced Material, Tohoku University, Sendai, 980-8577,Japan (Japan); Shi, Fei; Dong, Xiao-Li; Xu, Qiang [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Yin, Shu; Sato, Tsugio [Institute of Multidisciplinary Research for Advanced Material, Tohoku University, Sendai, 980-8577,Japan (Japan)

    2013-10-15

    In order to further improve the near-infrared shielding properties of cesium tungsten bronze (Cs{sub x}WO{sub 3}) for solar filter applications, Cs{sub x}WO{sub 3} particles were prepared by solvothermal reaction method and the effects of nitrogen annealing on the microstructure and near-infrared shielding properties of Cs{sub x}WO{sub 3} were investigated. The obtained Cs{sub x}WO{sub 3} samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and spectrophotometer. The results indicate that nanosheet-like Cs{sub x}WO{sub 3} particles with hexagonal structure began to transform into nanorods after annealed at temperature higher than 600 °C. The near-infrared shielding properties of Cs{sub x}WO{sub 3} particles could be further improved by N{sub 2} annealing at 500–700 °C. Particularly, the 500 °C-annealed Cs{sub x}WO{sub 3} samples in the N{sub 2} atmosphere showed best near-infrared shielding properties. It was suggested that the excellent near-infrared shielding ability of the 500 °C-annealed Cs{sub x}WO{sub 3} samples is correlated with its minimum O/W atomic ratio and most oxygen vacancies. Highlights: • N{sub 2} annealing could further improve the near-infrared (NIR) shielding of Cs{sub x}WO{sub 3}. • Effects of N{sub 2} annealing on microstructure and NIR shielding of Cs{sub x}WO{sub 3} were studied. • The 500 °C-N{sub 2}-annealed Cs{sub x}WO{sub 3} exhibited minimum O/W ratio and most oxygen vacancies. • The 500 °C-N{sub 2}-annealed Cs{sub x}WO{sub 3} particles exhibited best NIR shielding properties.

  1. Electron microscopy characterization of mechanically alloyed and hot consolidates Cu-Cr3C<sub>2 particles

    Directory of Open Access Journals (Sweden)

    López, M.

    2005-08-01

    Full Text Available Mechanically alloyed copper-ceramic composites have been obtained with the purpose of studying their use as copper-based material for electrical equipment. For high-temperature applications, dispersion-strengthened copper alloys are attractive due to their excellent combination of thermal and electrical conductivity, mechanical strength retention and microstructural stability. In this work, powder mixtures of pure copper with 2 vol % Cr3C<sub>2, milled during 4, 6, 10, 12 and 15 h in a high-energy planetary balls mill under argon atmosphere, were consolidated by hot isostatic pressing, applying a pressure of 100 MPa at 1073 K for two hours, to obtain materials with a fine microstructure. The Cu-Cr3C<sub>2 alloys were studied by scanning electron microscopy (SEM, electron microprobe (EPMA and transmission electron microscopy (TEM. Mechanical properties and electrical conductivity were also studied. The average tensile strength and electrical conductivity were found to be 500 MPa and 50 % IACS, respectively. The Cr3C<sub>2 ceramics show good stability during hot consolidation. Contributing to a further strengthening of the alloy during the hot consolidation, uniformly-distributed Fe-carbide particles of nanometric size precipitated in the copper matrix. Fe-Cr oxycarbides formed in the interphase between Cr3C<sub>2 particles and the copper matrix cause the low ductility of Cu-Cr3C<sub>2 alloys. Said particles are attributed to impurities/contamination generated from the milling process.

    Se obtuvieron aleaciones compuestas de Cu-Cr3C<sub>2, aleadas mecánicamente, para estudiar futuras aplicaciones en componentes eléctricos. A altas temperaturas, las aleaciones de base cobre reforzadas por dispersión, son atractivas por su excelente conductividad térmica y eléctrica, propiedades mecánicas y estabilidad microstructural. En este estudio

  2. Exchange and crystal-field interactions in the antiferromagnets GdRh sub 2 Si sub 2 and TbRh sub 2 Si sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Szytula, A. (Inst. of Physics, Jagiellonian Univ., Cracow (Poland)); Radwanski, R.J.; Boer, F.R. de (Van der Waals-Zeeman Lab., Univ. van Amsterdam (Netherlands))

    1992-02-01

    Magnetization curves up to 35 T have been measured at 4.2 K on free powder particles of the antiferromagnets GdRh{sub 2}Si{sub 2} and TbRh{sub 2}Si{sub 2}. The magnetization process is analyzed within a two-sublattice model for antiferromagnets. For GdRh{sub 2}Si{sub 2} the intersublattice molecular-field coefficient amounts to 7.2 T f.u./{mu}{sub B}. For TbRh{sub 2}Si{sub 2} metamagnetic transitions at 8 and 15 T are observed. (orig.).

  3. Particle size, spin wave and surface effects on magnetic properties of MgFe{sub 2}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Aslibeiki, B., E-mail: b.aslibeiki@tabrizu.ac.ir [Department of Physics, University of Tabriz, Tabriz 51666-16471 (Iran, Islamic Republic of); Varvaro, G.; Peddis, D. [Istituto di Struttura della Materia, National Research Council, Monterotondo Scalo, Roma 00015 (Italy); Kameli, P. [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2017-01-15

    Magnesium ferrite, MgFe{sub 2}O{sub 4}, nanoparticles with a mean diameter varying from ∼6 to ∼17 nm were successfully synthesized using a simple thermal decomposition method at different annealing temperatures ranging in between 400 and 600 °C. Pure spinel ferrite nanoparticles were obtained at temperatures lower than 500 °C, while the presence of hematite (α-Fe{sub 2}O{sub 3}) impurities was observed at higher temperatures. Single-phase samples show a superparamagnetic behavior at 300 K, the saturation magnetization (M{sub s}) becoming larger with the increase of particles size. The temperature dependence of M{sub s} was explained in terms of surface spin-canting as well as spin wave excitations in the core. Using a modified Bloch law, [M{sub s}(T)=M{sub s}(0)(1−βT{sup α})], we observed a size dependent behavior of the Bloch constant β and the exponent α, whose values increase and decrease, respectively, as the particle size reduces. - Highlights: • MgFe{sub 2}O{sub 4} nanoparticles were synthesized using a thermal decomposition method. • Pure ferrite nanoparticles were obtained at temperatures lower than 500 °C. • Samples show a superparamagnetic behavior at room temperatures. • Spin wave excitations were studied using a modified Bloch law.

  4. CoPt and FePt magnetic alloys grown on van der Waals WSe{sub 2}(0001) surfaces and on arrays of SiO{sub 2} spherical particles

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, Denys

    2008-06-06

    regard an interesting approach, which combines non-magnetic spherical nanoparticle self-assembly with defined magnetic properties provided by a magnetic film, deposited onto the particles, was recently proposed. This enables an elegant possibility of creating magnetic nanostructure arrays with high perpendicular magnetic anisotropy provided by FePt and CoPt alloys, which is required for high thermal stability. The investigation of the magnetic and structural properties of these alloys grown on arrays of amorphous SiO{sub 2} nanospheres is thereafter discussed. (orig.)

  5. Projection of SO{sub 2}, NO{sub X}, NH{sub 3} and particle emissions - 2010-2030

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, O.-K.; Plejdrup, M.; Winther, M.; Hjorth Mikkelsen, M.; Albrektsen, R.; Nielsen, M.; Fauser, P.; Hoffmann, L.; Hjelgaard, K.; Gyldenkaerne, S.

    2012-01-15

    This report contains a description of models and background data for projection of SO{sub 2}, NO{sub x}, NH{sub 3}, NMVOC, TSP, PM{sub 10} and PM{sub 25} for Denmark. The emissions are projected to 2030 using basic scenarios together with the expected results of a few individual policy measures. Official Danish forecasts of activity rates are used in the models for those sectors for which the forecasts are available, i.e. the latest official forecast from the Danish Energy Agency. The emission factors refer either to international guidelines or are country-specific and refer to Danish legislation, Danish research reports or calculations based on emission data from a considerable number of plants. The projection models are based on the same structure and method as the Danish emission inventories in order to ensure consistency. (Author)

  6. Influence of ZnO and TiO{sub 2} particle sizes in the mechanical and dielectric properties of vulcanized rubber

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Neudys; Custal, Maria del Angels; Rodriguez, Daniel [Sicame Company, Barcelona (Spain); Riba, Jordi-Roger [Departament d' Enginyeria Eletrica, Universitat Politecnica de Catalunya, Terrasssa (Spain); Armelin, Elaine, E-mail: elaine.armelin@upc.edu [Universitat Politecnica de Catalunya, Barcelona (Spain)

    2017-07-15

    The novelty of the present study relies on the straightforward sonication of ZnO and TiO{sub 2} and incorporation to a complex formulation of latex, with other several organic-inorganic additives that influences the cross-linking reactions. The new elastomer with particles carefully sonicated exhibit improved electrical and mechanical properties. Strong interaction among the nanoparticles and the polymer amorphous phase has been proved by means of FTIR, SEM and XRD analyses. The synergistic effect of hybrid fillers with nanometric dimensions can be used to design high-performance natural rubber nanocomposites with enhanced electrical resistance and good cross-linking degree. (author)

  7. Efficiency of Cu{sub 2}O/BiVO{sub 4} particles prepared with a new soft procedure on the degradation of dyes under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera-Ruiz, Eduardo [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Centro de Investigación e Innovación en Ingeniería Aeronáutica, Carretera a Salinas Victoria, Km 2.3, 66600 Apodaca, NL (Mexico); García-Pérez, Ulises M., E-mail: ulisesma.garcia@gmail.com [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Centro de Investigación e Innovación en Ingeniería Aeronáutica, Carretera a Salinas Victoria, Km 2.3, 66600 Apodaca, NL (Mexico); Garza-Galván, María de la; Zambrano-Robledo, Patricia; Bermúdez-Reyes, Bárbara [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Centro de Investigación e Innovación en Ingeniería Aeronáutica, Carretera a Salinas Victoria, Km 2.3, 66600 Apodaca, NL (Mexico); and others

    2015-02-15

    Graphical abstract: - Highlights: • Cu{sub 2}O/BiVO{sub 4} p–n heterojunctions were synthesized by a simple impregnation method. • The photocatalytic performance was evaluated using a LED lamp as visible source. • The composite with 1 wt.% of Cu{sub 2}O exhibits the best visible-light-activity. • A mechanism for the carriers transfer is proposed. • Factors as pH and O{sub 2} were found to influence the degradation rate. - Abstract: Cu{sub 2}O/BiVO{sub 4} composites with different concentrations of Cu{sub 2}O were synthesized by a simple impregnation method at 200 °C under N{sub 2} atmosphere for 4 h. The as-synthesized samples were characterized by X-ray powder diffraction, scanning electron microscopy, UV–vis diffuse reflection absorption and vis photoluminescence. The morphology of the as-synthesized composites with different weight ratios of Cu{sub 2}O is composed by quasi-spherical and dendrite-like particles. The photocatalytic performance of the Cu{sub 2}O/BiVO{sub 4} composites was evaluated by degradation of methyl orange solutions under visible-LED irradiation. The results obtained show that the photocatalytic behavior of the p–n heterojunction Cu{sub 2}O/BiVO{sub 4} composites was better than pure Cu{sub 2}O and BiVO{sub 4}. The variation of the reaction parameters, such as solution pH and presence of O{sub 2}, improved the photocatalytic performance of Cu{sub 2}O/BiVO{sub 4} composite. Meanwhile, a possible mechanism for methyl orange photocatalytic degradation over Cu{sub 2}O/BiVO{sub 4} photocatalysts was proposed. The chemical stability and reusability of Cu{sub 2}O/BiVO{sub 4} powders were also investigated.

  8. A density functional theory study of the hydrates of NH{sub 3}{center_dot}H{sub 2}SO{sub 4} and its implications for the formation of new atmospheric particles

    Energy Technology Data Exchange (ETDEWEB)

    Ianni, J.C.; Bandy, A.R. [Drexel Univ., Philadelphia, PA (United States). Dept. of Chemistry

    1999-04-15

    The interest in tropospheric and stratospheric aerosols has risen in past years. This is primarily due to the fact that aerosols in the troposphere and stratosphere are altering the earth`s climate by scattering radiation directly or indirectly by changing the reflectivity of clouds. They have also been involved in indirectly depleting the Antarctic stratospheric ozone layer by converting relatively inert chlorine species to photochemically reactive species which are well-known ozone-destroying species. Density functional molecular orbital theory was used at the B3LYP/6-311++G(2d,2p)//B3LYP/6-311++G(2d,2p) level of theory to study the hydrates of NH{sub 3}{center_dot}H{sub 2}SO{sub 4}{center_dot}nH{sub 2}O for n = 0--5 and NH{sub 3}{center_dot}(H{sub 2}SO{sub 4}){sub 2}{center_dot}H{sub 2}O. Neutrals of the first four NH{sub 3}{center_dot}H{sub 2}SO{sub 4}{center_dot}nH{sub 2}O clusters (n = 0--4) spontaneously formed and were determined to be hydrogen-bonded molecular complexes of H{sub 2}SO{sub 4}, H{sub 2}O, and NH{sub 3}. Double ions (clusters containing a NH{sub 4}{sup +} cation and a HSO{sub 4}{sup {minus}} anion) spontaneously formed in clusters of NH{sub 3}{center_dot}{approximately}H{sub 2}SO{sub 4}{center_dot}nH{sub 2}O where n = 1--5. The energetics of the hydration and isomerization reactions also were calculated. Double ions are not energetically favorable until NH{sub 3}{center_dot}H{sub 2}SO{sub 4}{center_dot}4H{sub 2}O. The free energy of formation from free NH{sub 3} and H{sub 2}SO{sub 4}{center_dot}nH{sub 2}O had a maximum at n = 3 at room temperature with {Delta}G {approx} {minus}3 kcal/mol. NH{sub 3}{center_dot}(H{sub 2}SO{sub 4}){sub 2}{center_dot}H{sub 2}O was studied to see if NH{sub 3} can initiate new atmospheric particle growth. It has been shown that NH{sub 3} has no role in the initialization of new atmospheric particles.

  9. Electrical conductivity of oxides from molten state to glassy. Effect on the incorporation of RuO{sub 2} particles; Conductivite electrique des verres et fontes d'oxides. Effets de l'incorporation de particules RuO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Simonnet, C

    2004-07-01

    This study concerns the electrical conductivity of oxides from molten state to glassy state and, in particular, the effect of the incorporation of RuO{sub 2} particles in the context of vitrification of radioactive waste. The material of interest in the nuclear field is basically a viscous or vitreous borosilicate containing a dispersion of RuO{sub 2} microcrystals. A very simple model of this heterogeneous material has been studied in particular (SiO{sub 2}, B{sub 2}O{sub 3}, Na{sub 2}O, RuO{sub 2}). An original method of impedance measurement in the liquid at high temperature yields reliable electrical conductivity values over a temperature range covering the liquid and vitreous phases of the borosilicates studied. In the borosilicate matrix, alkaline transport is mainly responsible for the ionic conduction. The temperature dependence of the conductivity may thus be represented by an equation combining a VFT law and an Arrhenius law to represent the electrical conductivity above and below T{sub g}. Beyond a critical volume fraction V{sub c} {approx} 0.01 of RuO{sub 2}, an electronic contribution is added to the ionic contribution of the matrix and the electrical conductivity increases significantly with the RuO{sub 2} content. This effect is described in terms of electrical percolation of the particle network. An electronic mechanism by tunnel transfer between particles is demonstrated. A mathematical model is developed to describe this mechanism in the solid composite. Beyond T{sub g}, conduction by the tunnel effect persists and the partial solubilization of RuO{sub 2} appears to be mainly responsible for the significant increase in electronic conductivity with the temperature. (author)

  10. Electrodeposition and electrochemical characterisation of thick and thin coatings of Sb and Sb/Sb{sub 2}O{sub 3} particles for Li-ion battery anodes

    Energy Technology Data Exchange (ETDEWEB)

    Bryngelsson, Hanna; Eskhult, Jonas; Edstroem, Kristina; Nyholm, Leif [Department of Materials Chemistry, The Aangstroem Laboratory, Uppsala University, P.O. Box 538, SE-751 21 Uppsala (Sweden)

    2007-12-20

    The possibilities to electrodeposit thick coatings composed of nanoparticles of Sb and Sb{sub 2}O{sub 3} for use as high-capacity anode materials in Li-ion batteries have been investigated. It is demonstrated that the stability of the coatings depends on their Sb{sub 2}O{sub 3} concentrations as well as microstructure. The electrodeposition reactions in electrolytes with different pH and buffer capacities were studied using chronopotentiometry and electrochemical quartz crystal microbalance measurements. The obtained deposits, which were characterised with XRD and SEM, were also tested as anode materials in Li-ion batteries. The influence of the pH and buffer capacity of the deposition solution on the composition and particle size of the deposits were studied and it is concluded that depositions from a poorly buffered solution of antimony-tartrate give rise to good anode materials due to the inclusion of precipitated Sb{sub 2}O{sub 3} nanoparticles in the Sb coatings. Depositions under conditions yielding pure Sb coatings give rise to deposits composed of large crystalline particles with poor anode stabilities. The presence of a plateau at about 0.8 V versus Li{sup +}/Li due to SEI forming reactions and the origin of another plateau at about 0.4 V versus Li{sup +}/Li seen during the lithiation of thin Sb coatings are also discussed. It is demonstrated that the 0.4 V plateau is present for Sb coatings for which the (0 1 2) peak is the main peak in the XRD diffractogram. (author)

  11. Effect of Particle Size Upon Pt/SiO<sub>2 Catalytic Cracking of n-Dodecane Under Supercritical Conditions: in situ SAXS and XANES Studies

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sungwon; Lee, Sungsik; Kumbhalkar, Mrunmayi; Wiaderek, Kamila M.; Dumesic, James A; Winans, Randall E.

    2017-01-01

    The endothermic cracking and dehydrogenation of n-dodecane is investigated over well-defined nanometer size platinum catalysts supported on SiO<sub>2 to study the particle size effects in the catalytic cracking reaction, with simultaneous in situ monitoring of the particle size and oxidation state of the working catalysts by in situ SAXS (small angle X-ray scattering) and XAS (X-ray absorption spectroscopy). The selectivity toward olefins products was found dominant in the 1 nm size platinum catalysts, whereas paraffins are dominant in the 2 nm catalysts. This reveals a strong correlation between catalytic performance and catalyst size as well as the stability of the nanoparticles in supercritical condition of n-dodecane. The presented results suggest that controlling the size and geometric structure of platinum nanocatalysts could lead to a fundamentally new level of understanding of nanoscale materials by monitoring the catalysts in realistic reaction conditions.

  12. Influence on nickel particle size on the hydrodeoxygenation of phenol over Ni/SiO<sub>2

    DEFF Research Database (Denmark)

    Mortensen, Peter M.; Grunwaldt, Jan-Dierk; Jensen, Peter A.

    2016-01-01

    Hydrodeoxygenation (HDO) of phenol over nickel nano-particles of different size (5-22 nm) supported on SiO2 has been investigated in a batch reactor at 275 °C and 100 bar. Deoxygenation was only observed as a consecutive step of initial hydrogenation of phenol at the given conditions. Both the hy...

  13. Characterization investigations during mechanical alloying and sintering of Ni-W solid solution alloys dispersed with WC and Y{sub 2}O{sub 3} particles

    Energy Technology Data Exchange (ETDEWEB)

    Genc, Aziz, E-mail: agenc@itu.edu.t [Particulate Materials Laboratories, Department of Metallurgical and Materials Engineering, Istanbul Technical University, Maslak, 34469 Istanbul (Turkey); Luetfi Ovecoglu, M. [Particulate Materials Laboratories, Department of Metallurgical and Materials Engineering, Istanbul Technical University, Maslak, 34469 Istanbul (Turkey)

    2010-10-15

    Research highlights: {yields} Characterization investigations on the Ni-W solid solution alloys fabricated via mechanical alloying and the evolution of the properties of the powders with increasing MA durations. {yields} Reinforcement of the selected Ni-W powders with WC and Y{sub 2}O{sub 3} particles and further MA together for 12 h. {yields} There is no reported literature on the development and characterization of Ni-W solid solution alloys matrix composites fabricated via MA. {yields} Sintering of the developed composites and the characterization investigations of the sintered samples. {yields} Identification of new 'pomegranate-like' structures in the bulk of the samples. - Abstract: Blended elemental Ni-30 wt.% W powders were mechanically alloyed (MA'd) for 1 h, 3 h, 6 h, 12 h, 24 h, 36 h and 48 h in a Spex mixer/mill at room temperature in order to investigate the effects of MA duration on the solubility of W in Ni and the grain size, hardness and particle size. Microstructural and phase characterizations of the MA'd powders were carried out using X-ray diffractometer (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). On the basis of achieved saturation on the solid solubility, hardness and particle size, the Ni-30 wt.% W powders MA'd for 48 h were chosen as the matrix which was reinforced with different amounts of WC and/or with 1 wt.% Y{sub 2}O{sub 3} particles. The reinforced powders were further MA'd for 12 h. The MA'd powders were sintered at 1300 {sup o}C for 1 h under Ar and H{sub 2} gas flowing conditions. Microstructural characterizations of the sintered samples were conducted via XRD and SEM. Sintered densities were measured by using the Archimedes' method. Vickers microhardness tests were performed on both MA'd powders and the sintered samples. Sliding wear experiments were done in order to investigate wear behaviors of the sintered samples.

  14. Synthesis of metals chalcogenides nano-particles from H{sub 2}X (X=S, Se, Te) produced electrochemically; Synthese de nanoparticules de chalcogenures de metaux a partir de H{sub 2}X (X=S, Se, Te) produit electrochimiquement

    Energy Technology Data Exchange (ETDEWEB)

    Bastide, S.; Tena-Zaera, R.; Alleno, E.; Godart, C.; Levy-Clement, C. [Centre National de la Recherche Scientifique (CNRS), Lab. de Chimie Metallurgique des Terres Rares, 94 - Thiais (France); Hodes, G. [Weizmann Institute of Science, Rehovot (Israel)

    2006-07-01

    In this work, an electrochemical method to produce H{sub 2}X (X=S, Se, Te) hydrides in a controlled way (without being able to store them) and to transfer them directly in the synthesis reactor has been perfected. By this method, the use of H{sub 2}Te has been possible. The method uses the reduction of the elementary chalcogenide in acid medium. The Te being conductor, it can be directly used as electrode, on the other hand S and Se are insulators. Nevertheless, graphite-S or Se conducing composite electrodes can also be used. When the electrolyte composition (pH, salts presence) is well adjusted, the essential of the cathodic current is consumed by the chalcogenide reduction (low evolution of H{sub 2}) with faradic yields of about 100% for H{sub 2}S and H{sub 2}Se and 40% for HeTe. The use of H{sub 2}X allows the synthesis of nano-particles of metals chalcogenides directly by reaction with dissolved metallic salts in aqueous or organic medium and precipitation. Thus it has been possible to prepare all the CdX compounds under the form of nano-particles of diameter between 3 and 5 nm by bubbling of the gaseous hydrides in aqueous acetate solutions of Cd. In producing concomitantly H{sub 2}S and H{sub 2}Se, nano-particles of solid solutions CdS{sub x}Se{sub 1-x} have been synthesized too. (O.M.)

  15. Effect of annealing on particle size, microstructure and gas sensing properties of Mn substituted CoFe{sub 2}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, E. Ranjith, E-mail: ranjueaswar@gmail.com [Department of Physics, Dr. NGP Institute of Technology, Coimbatore 641048, Tamil Nadu (India); Kamzin, A.S. [Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); Janani, K. [Department of Physics, Kongunadu Arts and Science College, Coimbatore, Tamil Nadu (India)

    2016-11-01

    Microstructure, morphological and gas sensor studies of Mn substituted cobalt ferrite nanoparticles synthesized by a simple evaporation method and auto- combustion method. The influence of heat treatment on phase and particle size of spinel ferrite nanoparticles were determined by X-ray diffraction and Mossbauer spectroscopy. The XRD study reveals that the lattice constant and crystallite size of the samples increases with the increase of annealing temperature. Last one was confirmed by Mossbauer data. The lowest size of particles of MnCoFe{sub 2}O{sub 4} (~3 nm) is obtained by auto combustion method. The spherical shaped nanoparticles are recorded by TEM. Furthermore, conductance response of Mn–Co ferrite nanomaterial was measured by exposing the material to reducing gas like liquefied petroleum gas (LPG) which showed a sensor response of ~0.19 at an optimum operating temperature of 250 °C. - Highlights: • ~3 nm sized particles were prepared by auto combustion method. • Mossbauer study was analyzed for different annealed samples. • The size of the particles increased with increasing annealing temperature.

  16. Single-particle and spin-density wave charge dynamics in (TMTSF){sub 2}PF{sub 6} and (TMTSF){sub 2}AsF{sub 6}: a comparative overview

    Energy Technology Data Exchange (ETDEWEB)

    Vuletic, T.; Herman, D.; Biskup, N.; Omerzu, A.; Tomic, S. [Zagreb Univ. (Croatia). Inst. za Fiziku; Pinteric, M. [Zagreb Univ. (Croatia). Inst. za Fiziku; Faculty of Civil Engineering, Univ. of Maribor (Slovenia); Nagasawa, M. [Hokkaido Univ., Sapporo (Japan). Dept. of Physics

    1999-12-01

    We present the results of DC and AC (100 mHz-1 MHz) electrical transport measurements in low and high electric fields performed in the spin-density wave (SDW) state of the Bechgaard salts (TMTSF){sub 2}PF{sub 6} and (TMTSF){sub 2}AsF{sub 6}. We argue that a degree of complex structure of the SDW ground state which is unfolded in a particular experiment depends strongly on the chosen experimental probe and the crystal measured. (orig.)

  17. Preparation of CuInS{sub 2} chalcopyrite films by reactive magnetron sputtering: Influence of the particle energy on morphological, electrical and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Stefan; Ellmer, Klaus [Hahn-Meitner-Institut, Dept. Solar Energetics, Berlin (Germany)

    2008-07-01

    Today magnetron sputtering is a common technique for large area depositions and already used to fabricate layers for thin film solar cells: the back contact (molybdenum) and front contact (zinc oxide) or for the deposition of metallic precursors. Nevertheless it is astonishing that this technique is not yet used for preparing the absorber layer in photovoltaic devices. Recently we have demonstrated that reactive magnetron sputtering from an indium and a copper target in an Ar/H{sub 2}S atmosphere is suited to prepare CuInS{sub 2} absorber films and solar cells with an efficiency of more than 10% in a one-step process without additional annealing procedures. In order to make full use of the advantages of a plasma-assisted deposition process: i) deposition at lower temperatures compared to pure thermal processes, ii) high chemical reactivity, iii) compact and well adherent films, we have investigated in this work the influence of the particle energies on the film growth and the electronic properties.

  18. The improvement of corrosion resistance of fluoropolymer coatings by SiO{sub 2}/poly(styrene-co-butyl acrylate) nanocomposite particles

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L. [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China); Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu (China); Song, R.G., E-mail: songrg@hotmail.com [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China); Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu (China); Li, X.W.; Guo, Y.Q.; Wang, C.; Jiang, Y. [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China); Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu (China)

    2015-10-30

    Highlights: • We first proposed the feasibility of organic-inorganic hybrid particles can be used to reduce free space of the fluoropolymer coatings. • By grafting poly(styrene-co-butyl acrylate), nano-silica particles can be better dispersed in the fluoropolymer coatings system. • The coating-substrates bound strength could be obviously seen in the FESEM cross-section images. • The effects of the corrosion resistance of fluoropolymer-coated steel were investigated by potentiodynamic polarization and EIS. • Using models to analysis the anticorrosion mechanism of nanocomposite coatings. - Abstract: The effects of nano-silica particles on the anticorrosion properties of fluoropolymer coatings on mild steel have been investigated in this paper. In order to enhance the dispersibility of nano-silica in fluoropolymer coatings, we treated the surface of nano-silica with poly(styrene-co-butyl acrylate) (P(St-BA)). The surface grafting of P(St-BA) on the nanoparticles were detected using Fourier transform infrared spectroscopy (FT-IR), thermo gravimetric analyzer (TGA), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The surface of nanocomposite coatings and the coating-substrates bond texture were detected by FE-SEM. We also used energy-dispersive X-ray spectroscopy (EDS) to analyze whether the nanocomposite particles were added into the fluoropolymer coatings. In addition, the influences of various nanoparticles on the corrosion resistance of fluoropolymer-coated steel were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results shown that nanocomposite particles can be dispersed better in fluoropolymer coatings, and the electrochemical results clearly shown the improvement of the protective properties of the nanocomposite coatings when 4 wt.% SiO{sub 2}/P(St-BA) was added to the fluoropolymer coatings.

  19. Surfactant modified MgFe{sub 2}O{sub 4} nanopowders by reverse micelle processing: Effect of water to surfactant ratio (R) on the particle size and magnetic property

    Energy Technology Data Exchange (ETDEWEB)

    Chandradass, J.; Jadhav, Arvind H. [Energy and Environment Fusion Technology Center, Department of Environmental Engineering and Biotechnology, Myongji University, Yongin, Kyonggi-do 449-728 (Korea, Republic of); Kim, Hern, E-mail: hernkim@mju.ac.kr [Energy and Environment Fusion Technology Center, Department of Environmental Engineering and Biotechnology, Myongji University, Yongin, Kyonggi-do 449-728 (Korea, Republic of)

    2012-01-15

    Nanoparticles of surfactant modified MgFe{sub 2}O{sub 4} have been synthesized by reverse micelle processing using tertiary system of heptane/Igepal CO 520/H{sub 2}O. The effect of water to surfactant ratio on the particle size and magnetic property has been studied. X-ray diffraction analysis confirms that MgFe{sub 2}O{sub 4} nanoparticles are crystalline in nature with cubic spinel structure. The average particle size increases with increase in water to surfactant ratio. The Fourier transform infrared (FTIR) analysis confirms that the surface of MgFe{sub 2}O{sub 4} nanoparticles was coated with surfactants. The saturation magnetization ranged from 14.4 to 40.05 emu/g was measured by Superconducting Quantum Interference Device Magnetometry (SQUID).

  20. CO{sub 2} laser cleaning of hydrophilic oxidized silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Boughaba, S.; Sacher, E.; Meunier, M. [Ecole Polytechnique, Montreal, Quebec (Canada). Dept. de Genie Physique

    1996-12-31

    Efficient sub-half-micron particle contaminant removal is currently one of the most challenging tasks the microelectronics industry has to meet. The removal of particles as small as 0.1 {micro}m was achieved using a pulsed CO{sub 2} laser to induce the explosive vaporization of condensed water. The surfaces used were hydrophilic oxidized silicon. The contaminant particles were 0.1 {micro}m alumina, 0.1--0.2 {micro}m fumed silica, and 0.1 {micro}m polystyrene latex; their zeta potentials in water vary from positive to negative. The effect of the laser beam energy flux on the cleaning efficiency was thoroughly investigated. The effect of the laser beam energy flux on the cleaning efficiency was thoroughly investigated. It was varied between 0.5 and 3 J/cm{sup 2}. Whatever the nature of the contaminants, the cleaning process was characterized by an upper limit, the surface damage threshold energy density, determined to be 1.5 J/cm{sup 2}. If the removal efficiency drops for the lowest beam energy flux, i.e., 0.5 J/cm{sup 2}, and 0.1 {micro}m Al{sub 2}O{sub 3} particles, no single, sharp removal threshold was observed. Another parameter of importance investigated was the thickness of the condensed water. It was varied by changing the time of exposure of the substrate surface to water vapor before laser irradiation, the vapor flow being fixed to 4,700 ml/min. Exposure times ranging from 1.5 to 2.5 s were evaluated to be the most effective.

  1. Enhanced thermoelectric properties in p-type Bi{sub 0.4}Sb{sub 1.6}Te{sub 3} alloy by combining incorporation and doping using multi-scale CuAlO{sub 2} particles

    Energy Technology Data Exchange (ETDEWEB)

    Song, Zijun; Liu, Yuan; Zhou, Zhenxing; Lu, Xiaofang; Wang, Lianjun [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai (China); Institute of Functional Materials, Donghua University, Shanghai (China); Zhang, Qihao [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai (China); University of Chinese Academy of Sciences, Beijing (China); Jiang, Wan [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai (China); Institute of Functional Materials, Donghua University, Shanghai (China); School of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen (China); Chen, Lidong [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai (China)

    2017-01-15

    Multi-scale CuAlO{sub 2} particles are introduced into the Bi{sub 0.4}Sb{sub 1.6}Te{sub 3} matrix to synergistically optimize the electrical conductivity, Seebeck coefficient, and the lattice thermal conductivity. Cu element originating from fine CuAlO{sub 2} grains diffuses into the Bi{sub 0.4}Sb{sub 1.6}Te{sub 3} matrix and tunes the carrier concentration while the coarse CuAlO{sub 2} particles survive as the second phase within the matrix. The power factor is improved at the whole temperatures range due to the low-energy electron filtering effect on Seebeck coefficient and enhanced electrical transport property by mild Cu doping. Meanwhile, the remaining CuAlO{sub 2} inclusions give rise to more boundaries and newly built interfaces scattering of heat-carrying phonons, resulting in the reduced lattice thermal conductivity. Consequently, the maximum ZT is found to be enhanced by 150% arising from the multi-scale microstructure regulation when the CuAlO{sub 2} content reaches 0.6 vol.%. Not only that, but the ZT curves get flat in the whole temperature range after introducing the multi-scale CuAlO{sub 2} particles, which leads to a remarkable increase in the average ZT. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Comparison of core-shell particles and sub-2μm fully porous particles for use as ultrafast second dimension columns in two-dimensional liquid chtomatography.

    Science.gov (United States)

    Haidar Ahmad, Imad A; Soliven, Arianne; Allen, Robert C; Filgueira, Marcelo; Carr, Peter W

    2015-03-20

    The peak capacity of small columns packed with 2.7μm core-shell particles and 1.8μm fully porous particles were compared at high temperatures using very steep (fast) gradient conditions and quite high linear velocities using the same instrument configuration as used to transfer first dimension effluent to the second dimension column as done in on-line comprehensive two-dimensional liquid chromatography. The experimental peak capacities of small columns (2.1mm×30mm) packed with both types of particles were measured with fast gradients (9s to 2min) at high temperature (95°C) using both the same flow rate (1.75mL/min) and then at different flow rates at the same pressure (400bar). Equal or slightly better peak capacities were achieved with the core-shell particle columns as compared to the fully porous particle columns at the same backpressure or the same flow rate. However, core-shell particles offer a real advantage over the smaller, fully porous particles because they can be operated at higher flow rates thus gradient mixer flush out and column reequilibration can be done in less time thereby allowing a greater fraction of the second dimension cycle time to be dedicated to the gradient time. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Assessment of inorganic content of PM{sub 2.5} particles sampled in a rural area north-east of Hanoi, Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Gatari, Michael J.; Boman, Johan; Wagner, Annemarie; Janhaell, Sara; Isakson, Jan [Chemistry Department, Atmospheric Science, Goeteborg University, SE-412 96 Goeteborg (Sweden)

    2006-09-15

    Atmospheric aerosols from seven rural sites in northern Vietnam, east of Hanoi, were sampled and analyzed. The aim of the study was to evaluate trace elemental and black carbon (BC) concentrations in fine particles (PM{sub 2.5}) and to investigate the influence of the Pha Lai power plant and other pollution sources on regional air quality. Seven measurement stations were set up at selected rural sites and a campaign consisting of 12 two-day measurement periods was conducted from the end of May until the end of October 2000. At each location a pair of samplers was installed consisting of a cyclone loaded with Teflon filters and a modified Millipore air monitoring cartridge loaded with glass fibre filters. The obtained samples were analyzed for trace elements by Energy Dispersive X-ray Fluorescence (EDXRF), while a black smoke detector was used for BC analysis. Seventeen trace elements were analyzed; Br, Ca, Cl, Cr, Cu, Fe, K, Mn, Ni, Pb, Rb, S, Se, Sr, Ti, V and Zn and their concentrations evaluated. The results showed that BC, Ca, Cl, Fe, K and S dominated in the sampled atmospheric aerosols. The measured concentrations of the potentially hazardous trace elements Cr, Mn, Ni and Pb were all below the limits defined by Vietnamese standards of ambient air quality. Statistical evaluations indicated that coal and heavy fuel oil combustion were major sources of atmospheric pollutants in the area and that biomass burning and road transport had a marked influence on regional air quality. It was concluded that the Pha Lai power plant was the major source of coal combustion emissions. Trace element emissions originating from river transportation were suggested as another major source of atmospheric pollutants. The results indicate that the elemental concentrations in PM{sub 2.5} are strongly influenced by seasonal variations. Further measurements are required to identify the impact of long-range transported continental air masses on the air quality of the investigated rural

  4. Influence of the size of MoS{sub 2} particles supported on alumina on the activity and the selectivity of hydro-treating reactions; Influence de la taille des particules de MoS{sub 2} supportees sur alumine sur l`activite et la selectivite des reactions d`hydrotraitement

    Energy Technology Data Exchange (ETDEWEB)

    Da Silva, P.

    1998-01-14

    The influence of the size of molybdenum disulfide particles supported on alumina on hydro-desulfurization and hydrogenation reactions has been studied. Different methods have been used to modify the length and the stacking of MoS{sub 2} slabs. MoS{sub 2} slab length measured from Electron Microscopy is increased from 20 to 40 angstroms by increasing loading from 4 to 22 % pds in Mo. These catalysts have been tested and characterised by different techniques. Increasing the sulfiding temperature also leads to an increase in MoS{sub 2} slab length. Bulk MoS{sub 2} and MoS{sub 2}/Al{sub 2}O{sub 3} showing high MoS{sub 2} slab stacking have been prepared from ammonium tetra-thio-molybdate salt. Sulfide phase characterisation results and an hexagonal MoS{sub 2} slab model have been used to estimate a number of edge and corner Mo ions. Catalysts have been characterised by Temperature Programmed Reduction and by CO adsorption at low temperatures (infra-red). Edge and corner Mo ions site densities determined by these techniques are linearly correlated with the number of sites calculated from the hexagonal MoS{sub 2} slab model and the characterisation results. Catalysts have been tested at 350 deg. C, under a total pressure of 4,5 MPa for dibenzo-thiophene hydro-desulfurization and 1-methyl naphthalene hydrogenation in the presence of nitrogen compounds. Linear correlations have been obtained between the catalytic activity and the number of edge and corner Mo sites estimated from different techniques. These results obtained from independent techniques clearly show the essential part played by edge and corner sites on catalytic activity. MoS{sub 2} slab length has no influence on the selectivity hydrogenation/hydro-desulfurization of tested catalysts. On the other side, the increase o stacking of MoS{sub 2} slab un-favours the hydrogenation reaction when compared to the hydro-desulfurization reaction. (author) 169 refs.

  5. Nanopowders M{sub 2}O{sub 3} (M = Y, La, Yb, Nd) with spherical particles and laser ceramics based on them

    Energy Technology Data Exchange (ETDEWEB)

    Bagayev, Sergei N; Kaminskii, Alexandr A; Kopylov, Yu L; Kravchenko, V B; Tolmachev, A V; Shemet, V V; Yavetskii, R P

    2013-03-31

    We have considered the problems of agglomeration of yttrium aluminium garnet (YAG) nanopowders prepared by chemical co-precipitation of precursors from aqueous solutions and subsequent calcination. To fabricate YAG and Y{sub 2}O{sub 3} laser ceramic samples with high optical transmittance and reproducible characteristics, we have developed a method for producing non-agglomerated nanopowders of pure and doped Y{sub 2}O{sub 3} by homogeneous chemical precipitation. Nanopowders Y{sub 2}O{sub 3} with La and Yb as well as mixtures of Y{sub 2}O{sub 3} : Nd and several commercial nanopowders of aluminium oxide have been compacted; optimised compacting technique have been selected; ceramic samples (Y, La, Yb){sub 2}O{sub 3} and YAG : Nd with high optical transmittance at a wavelength of 1 {mu}m have been produced by solid-phase synthesis. (extreme light fields and their applications)

  6. First results on Fe solid-phase extraction from coastal seawater using anatase TiO{sub 2} nano-particles

    Energy Technology Data Exchange (ETDEWEB)

    Quetel, Christophe R.; Petrov, Ivan [Joint Research Centre - European Commission, Institute for Reference Materials and Measurements, Geel (Belgium); Vassileva, Emilia [Joint Research Centre - European Commission, Institute for Reference Materials and Measurements, Geel (Belgium); IAEA-Marine Environment Laboratories, Principality of Monaco (Monaco); Chakarova, Kristina; Hadjiivanov, Konstantin I. [Bulgarian Academy of Sciences, Institute of General and Inorganic Chemistry, Sofia (Bulgaria)

    2010-03-15

    This paper describes the application of TiO{sub 2} nano-particles (anatase form) for the solid-phase extraction of iron from coastal seawater samples. We investigated the adsorption processes by infra-red spectroscopy. We compared in batch and on-(mini)column extraction approaches (0.1 and 0.05 g TiO{sub 2} per sample, respectively), combined to external calibration and detection by inductively coupled plasma mass spectrometry at medium mass resolution. Globally, this titania phase was slightly more efficient with seawater than with ultra-pure water, although between pH 2 and pH 7, the Fe retention efficiency progressed more in ultra-pure water than in seawater (6.9 versus 4.8 times improvement). Different reaction schemes are proposed between Fe(III) species and the two main categories of titania sites at pH 2 (adsorption of [FeL{sub x}]{sup (3-x)+} via possibly the mediation of chlorides) and at pH 7 (adsorption of [Fe(OH){sub 2}]{sup +} and precipitation of [Fe(OH){sub 3}]{sup 0}). Under optimised conditions, the inlet system was pre-cleaned by pumping 6% HCl for {proportional_to}2 h, and the column was conditioned by aspirating ultra-pure water (1.7 g min {sup -1}) and 0.05% ammonia (0.6 g min {sup -1}) for 1 min. Then 3 g seawater sample was loaded at the same flow rate while being mixed on-line with 0.05% ammonia at 0.6 g min {sup -1} to adjust the pH to 7. The iron retained on the oxide powder was then eluted with 3 g 6% HCl (<0.002% residual salinity in the separated samples). The overall procedural blank was 220 {+-} 46 (2 s, n = 16) ng Fe kg {sup -1} (the titania was renewed in the column every 20 samples, with 2-min rinsing in between samples with 6% HCl at 1.5 g min {sup -1}). The recovery estimated from the Canadian certified reference material CASS-2 was 69.5 {+-} 7.6% (2 s, n = 4). Typically, the relative combined uncertainty (k = 2) estimated for the measurement of {proportional_to}1 {mu}g Fe kg {sup -1} (0.45 {mu}m filtered and acidified to pH 1

  7. Characterization of magnetic nano particles of CoFe{sub 2}O{sub 4} and CoZnFe{sub 2}O{sub 4} prepared by the chemical co-precipitation method; Caracterizacion de nanoparticulas magneticas de CoFe{sub 2}O{sub 4} y CoZnFe{sub 2}O{sub 4} preparadas por el metodo de coprecipitacion quimica

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, J.; Zambrano, G.; Gomez, M. E. [Universidad del Valle, Departamento de Fisica, Laboratorio de Peliculas Delgadas, Ciudad Universitaria Melendez, 25360 Cali (Colombia); Prieto, P. [Universidad del Valle, Centro de Excelencia en Nuevos Materiales, Ciudad Universitaria Melendez, 25360 Cali (Colombia); Espinoza B, F. J., E-mail: javierlo21@gmail.com [IPN, Centro de Investigacion y de Estudios Avanzados, Unidad Queretaro, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, 76230 Queretaro (Mexico)

    2012-07-01

    Magnetic cobalt ferrite nanoparticles of CoFe{sub 2}O{sub 4} and CoZnFe{sub 2}O{sub 4} were prepared by co-precipitation technique from aqueous salt solutions of Co (II), ZnSO{sub 4} and Fe (III), in an alkaline medium. CoFe{sub 2}O{sub 4} powder samples were structurally characterized by X-ray diffraction, showing the presence of the most intense peat at 2{theta} = 413928{sup o} (Co K{alpha}1) corresponding to the (311) crystallographic orientation of the CoFe{sub 2}O{sub 4} spinel phase. The mean size of the crystalline of CoFe{sub 2}O{sub 4} and CoZnFe{sub 2}O{sub 4} nanoparticles determined from the full width at half maximum of the strongest reflection of the (311) peak by using the Scherrer approximation was calculated to be 11.4 and 7.0 ({+-} o.2) nm, respectively. Transmission electron microscopy studies permitted determining nanoparticle size of CoZnFe{sub 2}O{sub 4}. Fourier transform infrared spectroscopy was used to confirm the formation of Fe-O bonds, allowing identifying the presence of ferrite spinel structure. Magnetic properties were investigated with the aid of a vibrating sample magnetometer at room temperature Herein, the sample showed superparamagnetic behavior, determined by the hysteresis loop finally, due to the hysteresis loop of the CoZnFe{sub 2}O{sub 4} is very small, our magnetic nanoparticles can be considered as a soft magnetic material. These magnetic nanoparticles have interesting technological applications in biomedicine given their biocompatibility, in nano technology, and in ferro fluid preparation. (Author)

  8. Effect of particle size and adsorbates on the L{sub 3}, L{sub 2} and L{sub 1} x-ray absorption near edge structure of supported Pt nanoparaticles.

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Y.; Jelic, J.; Nitsche, L. C.; Meyer, R.; Miller, J. (Chemical Sciences and Engineering Division); (Univ. of Illinois at Chicago)

    2011-04-01

    Pt nano-particles from about 1 to 10 nm have been prepared on silica, alkali-silica, alumina, silica-alumina, carbon and SBA-15 supports. EXAFS spectra of the reduced catalysts in He show a contraction of the Pt-Pt bond distance as particle size is decreased below 3 nm. The bond length decreased as much as 0.13 {angstrom} for 1 nm Pt particles. Adsorption of CO and H{sub 2} lead to a increase in Pt-Pt bond distance to that near Pt foil, e.g., 2.77 {angstrom}. In addition to changes in the Pt bond distance with size, as the particle size decreases below about 5 nm there is a shift in the XANES to higher energy at the L{sub 3} edge, a decrease in intensity near the edge and an increase in intensity beyond the edge. We suggest these features correspond to effects of coordination (the decrease at the edge) and lattice contraction (the increase beyond the edge). At the L{sub 2} edge, there are only small shifts to higher energy at the edge. However, beyond the edge, there are large increases in intensity with decreasing particle size. At the L{sub 1} edge there are no changes in position or shape of the XANES spectra. Adsorption of CO and H{sub 2} also lead to changes in the L{sub 3} and L{sub 2} edges, however, no changes are observed at the L1 edge. Density Functional Theory and XANES calculations show that the trends in the experimental XANES can be explained in terms of the states available near the edge. Both CO and H{sub 2} adsorption result in a depletion of states at the Fermi level but the creation of anti-bonding states above the Fermi level which give rise to intensity increases beyond the edge.

  9. Statistical evaluation of potential damage to the Al(OH){sub 3} layer on nTiO{sub 2} particles in the presence of swimming pool and seawater

    Energy Technology Data Exchange (ETDEWEB)

    Virkutyte, Jurate [Pegasus Technical Services, Inc (United States); Al-Abed, Souhail R., E-mail: al-abed.souhail@epa.gov [U.S. Environmental Protection Agency, National Risk Management Research Laboratory (United States)

    2012-03-15

    Nanosized TiO{sub 2} particles (nTiO{sub 2}) are usually coated with an Al(OH){sub 3} layer when used in sunscreen to shield against the harmful effects of free radicals that are generated when these particles are exposed to UV radiation. Therefore, it is vital to insure the structural stability of these particles in the environment where the protective layer may be damaged and adverse health and environmental effects can occur. This study utilized X-ray analysis (SEM-EDS) to provide a qualitative and semi-quantitative assessment of the chemical and physical characteristics of Al(OH){sub 3}-coated original and damaged nTiO{sub 2} particles (used in sunscreen lotion formulations) in the presence of both swimming pool and seawater. Also, by utilizing statistical tools, a distribution of Al/Ti (%) on the particle surface was determined and evaluated. It was found that 45 min of treatment with swimming pool and seawater significantly induced the redistribution of Al/Ti (%), which changed the surface characteristics of particles and, therefore, may have induced undesired photo-activity and the consequent formation of free radicals.

  10. Understanding RuO{sub 2}.xH{sub 2}O/carbon nanofibre composites as supercapacitor electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Pico, F.; Rojas, R.M.; Amarilla, J.M.; Rojo, J.M. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), Cantoblanco, Sor Juana Ines de la Cruz 3, E-28049 Madrid (Spain); Ibanez, J. [Centro Nacional de Investigaciones Metalurgicas, CSIC, Avda Gregorio del Amo 8, E-28040 Madrid (Spain); Lillo-Rodenas, M.A.; Linares-Solano, A. [MCMA, Departamento de Quimica Inorganica, Universidad de Alicante, P.O. Box 99, E-03080 Alicante (Spain)

    2008-01-21

    Composites made from RuO{sub 2}.xH{sub 2}O particles supported on carbon nanofibres (CNF) have been prepared for supercapacitor electrodes. CNF, produced by Grupo Antolin Ing. SA. using a floating catalyst procedure was treated either in HCl or in HNO{sub 3}. Then the composites were obtained by impregnation of CNF with an aqueous RuCl{sub 3}.0.5H{sub 2}O solution followed by filtering and alkali solution treatment. Heat treatment at 150 C for 2 h was done. Specific capacitance of the composites has been measured and discussed on the basis of their RuO{sub 2}.xH{sub 2}O content and RuO{sub 2}.xH{sub 2}O particle size. The composites having RuO{sub 2}.xH{sub 2}O contents below 11 wt% show RuO{sub 2}.xH{sub 2}O particles, which grow from 2 to 4 nm as the RuO{sub 2}.xH{sub 2}O content increases. The specific capacitance of supported RuO{sub 2}.xH{sub 2}O, which can be very high (up to 840 F g{sup -1}), decreases as the RuO{sub 2}.xH{sub 2}O content increases and RuO{sub 2}.xH{sub 2}O particles grow. The composites having RuO{sub 2}.xH{sub 2}O contents above 11 wt% show RuO{sub 2}.xH{sub 2}O particles of nearly constant size (4 nm); the effect of increasing the RuO{sub 2}.xH{sub 2}O content is to increase the amount of particles but not the size of the particles. In these composites the specific capacitance of supported RuO{sub 2}.xH{sub 2}O is nearly constant (440 F g{sup -1}) and close to bare RuO{sub 2}.xH{sub 2}O (460 F g{sup -1}). (author)

  11. Effect of pH on particles size and gas sensing properties of In{sub 2}O{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Anand, Kanica, E-mail: kanica.anand@yahoo.com; Thangaraj, Rengasamy; Singh, Ravi Chand [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India)

    2016-05-23

    In this work, indium oxide (In{sub 2}O{sub 3}) nanoparticles have been synthesized by co-precipitation method and the effect of pH on the structural and sensor response values of In{sub 2}O{sub 3} nanoparticles has been reported. X-ray diffraction pattern (XRD) revealed the formation of cubic phase In{sub 2}O{sub 3} nanoparticles. FESEM results indicate the formation of nearly spherical shape In{sub 2}O{sub 3} nanoparticles. The band gap energy value changed with change in pH value and found to have highest value at pH 9. Indium oxide nanoparticles thus prepared were deposited as thick films on alumina substrates to act as gas sensors and their sensing response to ethanol vapors and LPG at 50 ppm was investigated at different operating temperatures. It has been observed that all sensors exhibited optimum response at 300°C towards ethanol and at 400°C towards LPG. In{sub 2}O{sub 3} nanoparticles prepared at pH 9, being smallest in size as compared to other, exhibit highest sensor response (SR).

  12. Modeling char conversion under suspension fired conditions in O{sub 2}/N{sub 2} and O{sub 2}/CO{sub 2} atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Jacob Brix; Peter Arendt Jensen; Anker Degn Jensen [Department of Chemical and Biochemical Engineering, Lyngby (Denmark)

    2011-06-15

    The aim of this investigation has been to model combustion under suspension fired conditions in O{sub 2}/N{sub 2} and O{sub 2}/CO{sub 2} mixtures. Experiments used for model validation have been carried out in an electrically heated Entrained Flow Reactor (EFR) at temperatures between 1173 K and 1673 K with inlet O{sub 2} concentrations between 5 and 28 vol.%. The Coal Combustion Model, COCOMO, includes the three char morphologies: cenospheric char, network char and dense char each divided between six discrete particle sizes. Both combustion and gasification with CO{sub 2} are accounted for and reaction rates include thermal char deactivation, which was found to be important for combustion at high reactor temperatures and high O{sub 2} concentrations. COCOMO show in general good agreement with experimental char conversion profiles at conditions covering zone I-III. From the experimental profiles no effect of CO{sub 2} gasification on char conversion has been found. COCOMO does however suggest that CO{sub 2} gasification in oxy-fuel combustion at low O{sub 2} concentrations can account for as much as 70% of the overall char consumption rate during combustion in zone III. 54 refs., 20 figs., 4 tabs., 2 apps.

  13. Synthesis of PtSn nanostructured catalysts supported over TiO{sub 2} and Ce-doped TiO{sub 2} particles for the electro-oxidation of ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, A.E. [Instituto de Ingeniería Electroquímica y Corrosión (INIEC), CONICET, Universidad Nacional del Sur. Av. Alem 1253, Bahía Blanca B8000CPB (Argentina); Gravina, A.N. [Departamento de Química, INQUISUR, CONICET, Universidad Nacional del Sur, Av. Alem 1253, Bahía Blanca B8000CPB (Argentina); Sieben, J.M., E-mail: jmsieben@uns.edu.ar [Instituto de Ingeniería Electroquímica y Corrosión (INIEC), CONICET, Universidad Nacional del Sur. Av. Alem 1253, Bahía Blanca B8000CPB (Argentina); Messina, P.V. [Departamento de Química, INQUISUR, CONICET, Universidad Nacional del Sur, Av. Alem 1253, Bahía Blanca B8000CPB (Argentina); Duarte, M.M.E. [Instituto de Ingeniería Electroquímica y Corrosión (INIEC), CONICET, Universidad Nacional del Sur. Av. Alem 1253, Bahía Blanca B8000CPB (Argentina)

    2016-09-15

    Highlights: • PtSn particles supported on TiO2 and Ce-doped TiO2 were evaluated as catalysts for EOR. • PtSn/TiO2 showed better mass current and higher TON than PtSn/Ce–TiO2 materials. • The activity for EOR decreased markedly with increasing Ce content in the TiO2. - Abstract: PtSn/TiO2 and PtSn/Ce-doped TiO2 catalysts were synthesized and evaluated for ethanol electro-oxidation in acid media. Titanium dioxide and Ce-doped TiO2 nanoparticles were prepared by hydrothermal method followed by calcination at 923 K. Bimetallic PtSn catalysts supported on the oxide materials were synthesized by microwave assisted reduction in ethylene glycol (EG). The structural properties of the resulting materials were evaluated via TEM and XRD, and the compositions were assessed by EDX and ICP-AES analysis. PtSn nanoparticles of about 3–4 nm were deposited on TiO2 and Ce–TiO2 particles. It was found that the catalyst composition is scarcely influenced by the cerium content in the mixed oxides while the electrochemical surface area per unit mass decreases upon the incorporation of Ce in the anatase lattice. The electrochemical tests pointed out that the electrocatalytic activity for ethanol oxidation decreases markedly as the Ce content increases. The results indicate that the presence of cerium in the titanium dioxide crystalline network induces local structural and electronic modifications, thereby leading to a reduction of the crystallinity, surface conductivity and the amount of OH species adsorbed on the surface of the oxide support.

  14. The photocatalytic application and regeneration of anatase thin films with embedded commercial TiO{sub 2} particles deposited on glass microrods

    Energy Technology Data Exchange (ETDEWEB)

    Medina-Valtierra, Jorge [Departamento de Ingenieria Quimica y Bioquimica, Tecnologico de Aguascalientes, Av. Adolfo Lopez Mateos No. 182 Ote., Fracc. Bona Gens, Aguascalientes, Ags., 20256 (Mexico)]. E-mail: jormeval@yahoo.com; Garcia-Servin, Josafat [Departamento de Ingenieria Quimica y Bioquimica, Tecnologico de Aguascalientes, Av. Adolfo Lopez Mateos No. 182 Ote., Fracc. Bona Gens, Aguascalientes, Ags., 20256 (Mexico)]. E-mail: josgaser@yahoo.com.mx; Frausto-Reyes, Claudio [Centro de Investigaciones en Optica, A.C., Unidad Aguascalientes, Prol. Constitucion No. 607, Reserva de Loma Bonita, Aguascalientes, Ags., 20200 (Mexico)]. E-mail: cfraus@cio.mx; Calixto, Sergio [Centro de Investigaciones en Optica, A.C., Loma del Bosque No. 115, Col. Lomas del Campestre, Leon, Gto., 37150 (Mexico)]. E-mail: scalixto@cio.mx

    2006-03-15

    Anatase thin films (<200 nm in thickness) embedding Degussa P25 TiO{sub 2} were prepared by sol-gel method. TiO{sub 2}-anatase thin films were deposited on a fiberglass substrate and then ground to obtain glass microrods containing the composite films. The film structure was characterized using Raman spectroscopy, atomic absorption and UV-vis spectrophotometry, and atomic force microscopy. The photocatalytic activity of the composite films, calcined at 450 deg. C, and the regeneration of the activity under the same experimental conditions, were assessed using gas chromatography to study the photodegradation of phenol, an industrial pollutant, in water under 365 nm irradiation. The film with 15.0 wt.% of P25 TiO{sub 2} was found to be more photoactive (54 ppm of degraded phenol at 6 h of illumination) than the other ones.

  15. Spin-phonon coupling in rod-shaped half-metallic CrO sub 2 ultrafine particles: a magnetic Raman scattering study

    CERN Document Server

    Yu, T; Sun, W X; Lin, J Y; Ding, J

    2003-01-01

    Half-metallic CrO sub 2 powder compact with rod-shaped nanoparticles was studied by micro-Raman scattering in the presence of an external magnetic field at room temperature (300 K). In the low-field region (H <= 250 mT), the frequency and intensity of the E sub g mode, an internal phonon mode of CrO sub 2 , increase dramatically with increase in the magnetic field, while the corresponding linewidth decreases. The above parameters become constant when the CrO sub 2 powder enters the saturation state at higher magnetic field. The pronounced anomalies of the Raman phonon parameters under a low magnetic field are attributed to the spin-phonon coupling enhanced by the magnetic ordering, which is induced by the external magnetic field. (letter to the editor)

  16. Rapid determination of parabens in seafood sauces by high-performance liquid chromatography: A practical comparison of core-shell particles and sub-2 μm fully porous particles.

    Science.gov (United States)

    Ye, Jing; Cao, Xiaoji; Cheng, Zhuo; Qin, Ye; Lu, Yanbin

    2015-12-01

    In this work, the chromatographic performance of superficially porous particles (Halo core-shell C18 column, 50 mm × 2.1 mm, 2.7 μm) was compared with that of sub-2 μm fully porous particles (Acquity BEH C18 , 50 mm × 2.1 mm, 1.7 μm). Four parabens, methylparaben, ethylparaben, propylparaben, and butylparaben, were used as representative compounds for calculating the plate heights in a wide flow rate range and analyzed on the basis of the Van Deemter and Knox equations. Theoretical Poppe plots were constructed for each column to compare their kinetic performance. Both phases gave similar minimum plate heights when using nonreduced coordinates. Meanwhile, the flat C-term of the core-shell column provided the possibilities for applying high flow rates without significant loss in efficiency. The low backpressure of core-shell particles allowed this kind of column, especially compatible with conventional high-performance liquid chromatography systems. Based on these factors, a simple high-performance liquid chromatography method was established and validated for the determination of parabens in various seafood sauces using the Halo core-shell C18 column for separation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Effect of sintering temperature and the particle size on the structural and magnetic properties of nanocrystalline Li{sub 0.5}Fe{sub 2.5}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Shirsath, Sagar E., E-mail: shirsathsagar@hotmail.com [Department of Physics, Vivekanand College, Aurangabad 431004 (MS) (India); Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004 (MS) (India); Kadam, R.H. [Materials Science Research Laboratory, Shrikrishna Mahavidyalaya Gunjoti, Osmanabad (MS) (India); Gaikwad, Anil S. [Department of Physics, Vivekanand College, Aurangabad 431004 (MS) (India); Ghasemi, Ali [Materials Engineering Department, Malek Ashtar University of Technology, Shahin Shahr (Iran, Islamic Republic of); Morisako, Akimitsu [Spin Device Technology Center, Faculty of Engineering, Shinshu University, Nagano (Japan)

    2011-12-15

    Sintering temperature and particle size dependent structural and magnetic properties of lithium ferrite (Li{sub 0.5}Fe{sub 2.5}O{sub 4}) were synthesized and sintered at four different temperatures ranging from 875 to 1475 K in the step of 200 K. The sample sintered at 875 K was also treated for four different sintering times ranging from 4 to 16 h. Samples sintered at 1475 K have the cubic spinel structure with a small amount of {alpha}-Fe{sub 2}O{sub 3} (hematite) and {gamma}-Fe{sub 2}O{sub 3} (maghemite). The samples sintered at{<=}1275 K do not show hematite and maghemite phases and the crystals form the single phase spinel structure with the cation ordering on octahedral sites. Particle size of lithium ferrite is in the range of 13-45 nm, and is depend on the sintering temperature and sintering time. The saturation magnetization increased from 45 to 76 emu/g and coercivity decreases from 151 to 139 Oe with an increase in particle size. Magnetization temperature curve recorded in ZFC and FC modes in an external magnetic field of 100 Oe. Typical blocking effects are observed below about 244 K. The dielectric constant increases with an increase in sintering temperature and particle size. - Highlights: > Lithium ferrite with heat treatment. > Structure changes from disordered system to ordered system. > Magnetization increases with sintering temperature. > Blocking temperature increases with sintering temperature. > Coercivity decreases with sintering temperature.

  18. Simulation of coal particle burnup in a stationary laboratory-scale fluidized bed - formation mechanisms of NO{sub x} and N{sub 2}O; Simulation des Abbrands eines Kohlepartikels in einer stationaeren Laborwirbelschicht - Untersuchung der Mechanismen zur Bildung von NO{sub x} und N{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Loeffler, G.; Andahazy, A.; Wartha, C.; Winter, F.; Hofbauer, H.

    2001-07-01

    A model was developed that describes the combustion of single fuel particles in a laboratory-scale fluidized bed on the basis of detailed reaction mechanisms. The model was tested successfully; the results are described in detail. [German] Es wurde erfolgreich ein Modell fuer die Verbrennung von einzelnen Brennstoffpartikeln in einer Laborwirbelschicht unter Verwendung von detaillierten Reaktionsmechanismen entwickelt. Die Ergebnisse zeigen, dass heterogen katalysierte Reaktionen unter den untersuchten Bedingungen zumindest von gleicher Bedeutung wie die homogenen Gasphasenreaktionen sind; die heterogen katalysierten aber oft auch dominieren. Die Bildung von NO ist auch fuer den Umsatz der fluechtigen Kohlenwasserstoffe von grosser Bedeutung, da NO als homogener Katalysator die Kohlenwasserstoffoxidation bei Temperaturen, wie sie fuer Wirbelschichtfeuerungen typisch sind, beschleunigt. Waehrend NO waehrend der Entgasung sowohl aus HCN als auch aus NH{sub 3} gebildet wird, entstammt das Lachgas N{sub 2}O fast ausschliesslich der Oxidation von HCN. Abbaureaktionen dieser beiden Emissionen zu N{sub 2} sind unter den untersuchten Bedingungen von untergeordneter Bedeutung. Waehrend des Koksabbrands wird NO heterogen gebildet, waehrend das aus dem Koks freigesetzte HCN zum Teil zu N{sub 2}O umgewandelt wird. (orig.)

  19. Projection of SO{sub 2}, NO{sub X}, NMVOC, NH{sub 3} and particle emissions - 2005 to 2030

    Energy Technology Data Exchange (ETDEWEB)

    Boll Illerup, J.; Nielsen, Ole-Kenneth; Winther, M.; Hjorth Mikkelsen, M.; Nielsen, Malene; Fauser, P.; Gyldenkaerne, S.

    2008-05-15

    This report contains a description of models and background data for projection of SO{sub 2}, NO{sub X}, NH{sub 3}, NMVOC, TSP, PM{sub 10} and PM{sub 2.5} for Denmark. The emissions are projected to 2030 using basic scenarios together with the expected results of a few individual policy measures. Official Danish forecasts of activity rates are used in the models for those sectors for which the forecasts are available, i.e. the latest official forecast from the Danish Energy Authority. The emission factors refer to international guidelines and some are country-specific and refer to Danish legislation, Danish research reports or calculations based on emission data from a considerable number of plants. The projection models are based on the same structure and method as the Danish emission inventories in order to ensure consistency. (au)

  20. Structure and optical property changes of Nb{sub 2}O{sub 5} particles by Q-switched laser pulses in water

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Jing-Yi; Wu, Chao-Hsien; Zheng, Yuyuan; Shen, Pouyan [National Sun Yat-sen University, Department of Materials and Optoelectronic Science, Kaohsiung (China); Chen, Shuei-Yuan [I-Shou University, Department of Mechanical and Automation Engineering, Kaohsiung (China)

    2014-06-15

    Monoclinic H-type Nb{sub 2}O{sub 5} powders subjected to Q-switched laser pulses in water were characterized by X-ray/electron diffraction and optical spectroscopy to have a significant optical property change with accompanied transformation into orthorhombic T-, pseudohexagonal TT-type and an amorphous phase. The T-Nb{sub 2}O{sub 5} nanoparticles were (100), (010), (001) and (anti 201) faceted and commonly in oriented intergrowth with TT-type or amorphized domains retaining the polymerized block units of the relic H-type. Such multiple-phase nanoparticles were hydrogenated and densified to modify Raman and FTIR bands and to show visible absorptions corresponding to a broad minimum band gap of 2.3-2.8 eV for potential opto-catalytic and electrochromic applications. (orig.)

  1. Comparison of particle sizes between 238PuO<sub>2 before aqueous processing, after aqueous processing, and after ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Mulford, Roberta Nancy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-06

    Particle sizes determined for a single lot of incoming Russian fuel and for a lot of fuel after aqueous processing are compared with particle sizes measured on fuel after ball-milling. The single samples of each type are believed to have particle size distributions typical of oxide from similar lots, as the processing of fuel lots is fairly uniform. Variation between lots is, as yet, uncharacterized. Sampling and particle size measurement methods are discussed elsewhere.

  2. Photocatalytic activity of the binary composite CeO{sub 2}/SiO{sub 2} for degradation of dye

    Energy Technology Data Exchange (ETDEWEB)

    Phanichphant, Sukon [Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Nakaruk, Auppatham [Department of Industrial Engineering, Faculty of Engineering, Naresuan University, Phitsanulok 65000 (Thailand); Centre of Excellence for Innovation and Technology for Water Treatment, Naresuan University, Phitsanulok 65000 (Thailand); Channei, Duangdao, E-mail: duangdaoc@nu.ac.th [Department of Chemistry, Faculty of Science, Naresuan University, Phitsanulok 65000 (Thailand); Research Center for Academic Excellence in Petroleum, Petrochemicals and Advanced Materials, Naresuan University, Phitsanulok 65000 (Thailand)

    2016-11-30

    Highlights: • The enhanced photocatalytic activity of the CeO{sub 2}/SiO{sub 2} composite can be explained by the presence of the SiO{sub 2} adsorbent, which effectively increased the surface area of the CeO{sub 2}. • The increased surface area of CeO{sub 2} should be helpful to facilitate more effective adsorption sites, which enhances the photocatalytic degradation of organic pollutant significantly. • SiO{sub 2} modification is effective in separating the photogenerated electrons and holes, which is of great importance for photocatalytic activity. • SiO{sub 2} acted as a carrier for CeO{sub 2} attachment and avoided the agglomeration of CeO{sub 2} particles. - Abstract: In this study, CeO{sub 2} photocatalyst was modified by composite with SiO{sub 2} to increase efficiency and improve photocatalytic activity. The as-prepared SiO{sub 2} particles have been incorporated into the precursor mixture of CeO{sub 2} by homogeneous precipitation and subsequent calcination process. The phase compositions of CeO{sub 2} before and after compositing with SiO{sub 2} were identified by X-ray diffraction (XRD). The morphology and particle size of CeO{sub 2}/SiO{sub 2} composite was analyzed by high resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM). The results showed SiO{sub 2} spheres with the particle size approximately 100–120 nm, and a uniform layer of CeO{sub 2} nanoparticles with a diameter of about 5–7 nm that were fully composite to the surfaces of SiO{sub 2}. The X-ray photoelectron spectroscopy (XPS) technique was carried out in order to characterize the change in valence state and composite characteristic by shifted peaks of binding energies. The photocatalytic activity was studied through the degradation of Rhodamine B in aqueous solution under visible light exposure. The highest photocatalytic efficiency of CeO{sub 2}/SiO{sub 2} composite was also obtained. To explain the high photocatalytic

  3. Phase Transformation Behavior of Oxide Particles Formed in Mechanically Alloyed Fe-5Y{sub 2}O{sub 3} Powder

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ga Eon; Choi, Jung-Sun; Noh, Sanghoon; Kang, Suk Hoon; Choi, Byoung Kwon; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Deajeon (Korea, Republic of); Kim, Young Do [Hanyang University, Seoul (Korea, Republic of)

    2017-05-15

    The phase transformation behavior of the oxides formed in mechanically alloyed Fe-5Y{sub 2}O{sub 3} powder is investigated. Non-stoichiometric Y-rich and Fe-rich oxides with sizes of less than 300 nm are observed in the mechanically alloyed powder. The diffusion and redistribution reactions of the elements in these oxides during heating of the powder above 800 ℃ were observed, and these reactions result in the formation of a Y{sub 3}Fe{sub 5}O{sub 12} phase after heating at 1050 ℃. Thus, it is considered that the Y{sub 2}O{sub 3} powder and some Fe powder are formed from the non-stoichiometric Y-rich and Fe-rich oxides after the mechanical alloying process, and a considerable energy accumulated during the mechanical alloying process leads to a phase transformation of the Y-rich and Fe-rich oxides to Y{sub α}Fe{sub β}O{sub γ}-type phase during heating.

  4. Identification of metals into fine particles (PM{sub 2.5}) during the dry cold season in the Toluca City; Identificacion de metales en particulas finas (PM{sub 2.5}) durante la epoca seca-fria en la ciudad de Toluca

    Energy Technology Data Exchange (ETDEWEB)

    Martinez P, A. A. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Tollocan esquina Paseo Colon s/n, Toluca 50180, Estado de Mexico (Mexico); Aldape U, F. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)

    2008-07-01

    To know the elemental content of fine particles PM{sub 2.5} that can affect people in the Toluca City, such as metals and another, it was made a campaign collection of fine particles during dry-cold ( November 2006-March 2007). The aerosol samples were collected on Teflon filters with an equipment BGI model PQ200 mark authorized by the Environment Protection Agency (EPA), every other day with a time resolution of 24 h. The determination of the elemental composition of the samples was performed by means of the technique Particle Induced X-Ray Emission (PIXE). The results of the analysis showed consistently 13 elements S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, as, throughout the collection period. We calculated the enrich factor that separates the elements of the natural component of the anthropogenic component. The correlation matrix shows the pairs of elements that are contained in the same air mass as Vanadium and Nickel. From the results it is concluded that the sources that gave rise to these particles are the burning of fossil fuels in motor vehicles, lubricants, additives and burning tires wear of automotive vehicles, besides the products used in agricultural activities. (Author)

  5. The application of imperialist competitive algorithm for optimization of deposition rate in submerged arc welding process using TiO{sub 2} nano particle

    Energy Technology Data Exchange (ETDEWEB)

    Ghaderi, Mohammad Reza; Eslampanah, Amirhossein; Ghaderi, Kianoosh [Islamic Azad University, Sanandaj (Iran, Islamic Republic of); Aghakhani, Masood [Razi University, Kermanshah (Iran, Islamic Republic of)

    2015-01-15

    We used a novel optimization algorithm based on the imperialist competitive algorithm (ICA) to optimize the deposition rate in the submerged arc welding (SAW) process. This algorithm offers some advantages such as simplicity, accuracy and time saving. Experiments were conducted based on a five factor, five level rotatable central composite design (RCCD) to collect welding data for deposition rate as a function of welding current, arc voltage, contact tip to plate distance, welding speed and thickness of TiO{sub 2} nanoparticles coated on the plates of mild steel. Furthermore, regression equation for deposition rate was obtained using least squares method. The regression equation as the cost function was optimized using ICA. Ultimately, the levels of input variables to achieve maximum deposition rate were obtained using ICA. Computational results indicate that the proposed algorithm is quite effective and powerful in optimizing the cost function.

  6. Effect of particle size distribution on the structure, hyperfine, and magnetic properties of Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} nanopowders

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Kaustav; Das, G. C. [Department of Metallurgical and Material Engineering, Jadavpur University, Kolkata 700032 (India); Pati, Satya P.; Das, D. [UGC-DAE Consortium for Scientific Research, Kolkata Centre, III/LB-8, Bidhannagar, Kolkata 700 098 (India); Chattopadhyay, K. K., E-mail: kalyan-chattopadhyay@yahoo.com [Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University, Kolkata 700032 (India)

    2014-12-21

    Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} nano powders were synthesized by an auto combustion method and then heat treated at different temperatures in air for a fixed time. As a consequence, a distribution in particle size and strain was incorporated within the specimens, as estimated from the Rietveld refinement analysis of the powder x-ray diffraction data. The changes in the microstructure and crystal structure parameters were carefully extracted through the refinement analysis. Thermal annealing causes increment in the dispersion and mean of the size distribution. Reallocation of cations in the lattice sites occur as a consequence of the heat treatment which was manifested in their altered unit cell length (a), r.m.s. strain (〈ε{sup 2}〉{sup 1/2}), oxygen positional parameter (u), metal-oxygen bond lengths (R{sub OA} and R{sub OB}), and the band positions (ν{sub 1}and ν{sub 2}) in the vibrational spectroscopy. We also investigate the hyperfine and magnetic properties of the samples using different instrumental techniques (with different operating time scales) like Mössbauer spectroscopy, electron paramagnetic resonance spectroscopy, and superconducting quantum interference device magnetometry. Results show that the effect of particle size distribution was manifested in their hyperfine field distribution profile, paramagnetic resonance spectra, and magnetic anisotropy energy distribution profile. Co-existence of superparamagnetic and ferrimagnetic phase was recorded at room temperature in the samples when annealed at lower temperature. However, with increase in annealing temperature, the nature of the size distribution changes and ferrimagnetic ordering predominates for the larger size nanoparticles. Thus, the effect of particle size distribution on the structural, hyperfine, and magnetic properties of various Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} nanoparticles was investigated herein which hitherto has not been discussed in the literature.

  7. Spectroscopy of peaks at microwave range for nanostructure SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4} ferrite particles

    Energy Technology Data Exchange (ETDEWEB)

    Ariaee, Sina, E-mail: sina.ariaee@tabrizu.ac.ir; Mehdipour, Mostafa, E-mail: Mostafa_mehdipour67@yahoo.com; Moradnia, Mina, E-mail: mina.moradnia86@gmail.com

    2017-05-01

    In this paper, (SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4}) nanostructure ferrite particles were synthesized via the co-precipitation of chloride salts utilizing the sodium hydroxide solution. The resulting precursors were heat-treated at 1100 °C for 4 h. After cooling in the furnace, the ferrite powders were pressed at 0.1 MPa and then sintered at 1200 °C for 4 h. The spectroscopy and characterization of peaks at the microwave range (X-band) for the nanostructure ferrite particles were investigated by the ferromagnetic resonance/transmit-line theories and Reflection Loss (RL) plots. The extracted data from these theoretical and experimental results showed that the natural ferromagnetic resonance can be lead to the narrow peaks and the width of the peaks can be related to the periodic effects. Two kinds of peaks were seen for NiFe{sub 2}O{sub 4} at X-band (8–12 GHz); the narrow peak at (9.8 GHz) was remaining unchanged and consistent while the wide one was shifted from 11 GHz to 8.5 GHz by decreasing the thickness of the samples. These phenomena were also happened for SrFe{sub 12}O{sub 19} samples. The natural resonance was not happened due to the hard magnetic properties of these nano structure particles. - Highlights: • SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4} nanostructure ferrite particles were synthesized via the co-precipitation of chloride salts. • Two kinds of peaks were seen for NiFe{sub 2}O{sub 4} at X-band (8–12 GHz); these phenomena were also happened for SrFe{sub 12}O{sub 19} samples. • The narrow peaks were remained unchanged and consistent while the wide ones were shifted by decreasing the thickness of the samples. • Characterization procedure was conducted utilizing the ferromagnetic resonance/transmit-line theories and Reflection Loss (RL) plots. • It was concluded that the natural ferromagnetic resonance can be lead to the narrow peaks while the wide ones can be related to the periodic effects.

  8. Thermal morphological evolution of platinum nano-particles in Pt-Al{sub 2}O{sub 3} nano-composites

    Energy Technology Data Exchange (ETDEWEB)

    Maaza, M. [Nanosciences Laboratories, Solid State Materials Group, iTHEMBA LABS, PO Box 722, Somerset West 7129, Faure (South Africa)]. E-mail: maaza@tlabs.ac.za; Nemraoui, O. [Physics Department, Rand Afrikaans University, Auckland Park, PO Box 392, Johannesburg (South Africa); Sella, C. [Laboratoire d' Optique des Solides, Universite Pierre-Marie Curie, Paris VI (France); Lafait, J. [Laboratoire d' Optique des Solides, Universite Pierre-Marie Curie, Paris VI (France); Gibaud, A. [Laboratoire Surface and Interface, Universite du Maine, Le Mans (France); Pischedda, V. [High Pressure-High Temperature Group, University of the Witwatersrand-Johannesburg, Wits 2050, Johannesburg (South Africa)

    2005-08-29

    Temperature morphological evolution of nonpercolated granular nano-structures of platinum nano-particles embedded in an insulating alumina matrix was investigated by X-rays scattering in grazing angle reflection mode. In the investigated temperature range of 298-823 K, it was found that the annealing treatment tends to increase the Pt nano-particles' size and to produce a quasi-mono-disperse Pt nano-particles followed by a reduction of the barrier thickness between them. The percolation temperature is estimated to be of the order of 890 K. Using the rate constant governing the growth of the Pt nano-particles, the corresponding activation energy was determined to be about 90 kJ/mol.

  9. Nanoscopic platinum particles on TiO{sub 2}(110). STM and point-contact studies on the chemical and photosensitivity; Nanoskopische Platin-Teilchen auf TiO{sub 2}(110). STM- und Punktkontaktuntersuchungen zur chemischen und Photosensitivitaet

    Energy Technology Data Exchange (ETDEWEB)

    Koelbach, Johannes Micha

    2009-06-23

    In the ultra high vacuum produced nanoscopical platinum particles on TiO{sub 2}(110)- single crystal surfaces are contacted with the tunneltip of a raster tunnel microscope, and the chemical as well as photo sensitivity of an individual hetero contact are determined. For the experiments a UHV equipment was developed, equipped with methods to the controlled preparation and surface-analytic techniques (LEED, AES and STM). Platinum is resistively evaporated and thus small platinum particles with a size of about 8nm are generated on the pure titanium dioxide surface and characterized by STM and STS. A new developed oxygen source based on zirconoxide ceramics enables in-situ experiments for undisturbed determination of current-voltage characteristics in the tunneling and contact mode. A special preamplifier with controllable range of amplification is applied. Applying a voltage to the ceramic oxygen can be let into the UHV chamber by the oxygen source and the partial pressure can be adjusted within the range of 1.10{sup -10} mbar to 1.10{sup -5} mbar. The effect of the oxygen on the electrical characteristics of the Pt/TiO{sub 2}-contacts was proven. The clear dependence of the current-voltage characteristics on the oxygen partial pressure can be explained as a result of interface states due to the dissociation and adsorption of the oxygen, which determine the electrical characteristic of the contact. Schottky barriere heights and quality parameters were determined and compared with values of macroscopic surface contacts. For the investigations of the photo sensitivity a special STM head was developed, which enables the coupling of laser light with a wavelength of 413.1 nm. Irradiation of the nanoscopical Pt/TiO{sub 2}-contacts changes the current-voltage characteristics as well. The results of the power-dependent measurements refer to a temperature effect, that dominates the photoelectric effect. The combined power-and oxygen partial pressure dependent measurements are

  10. Macromodel for assessing residential concentrations of combustion-generated pollutants: Model development and preliminary predictions for CO, NO/sub 2/, and respirable suspended particles

    Energy Technology Data Exchange (ETDEWEB)

    Traynor, G.W.; Aceti, J.C.; Apte, M.G.; Smith, B.V.; Green, L.L.; Smith-Reiser, A.; Novak, K.M.; Moses, D.O.

    1989-01-01

    A simulation model (also called a ''macromodel'') has been developed to predict residential air pollutant concentration distributions for specified populations. The model inputs include the market penetration of pollution sources, pollution source characteristics (e.g., emission rates, source usage rates), building characteristics (e.g., house volume, air exchange rates), and meteorological parameters (e.g., outside temperature). Four geographically distinct regions of the US have been modeled using Monte Carlo and deterministic simulation techniques. Single-source simulations were also conducted. The highest predicted CO and NO/sub 2/ residential concentrations were associated with the winter-time use of unvented gas and kerosene space heaters. The highest predicted respirable suspended particulate concentrations were associated with indoor cigarette smoking and the winter-time use of non-airtight wood stoves, radiant kerosene heaters, convective unvented gas space heaters, and oil forced-air furnaces. Future field studies in this area should (1) fill information gaps identified in this report, and (2) collect information on the macromodel input parameters to properly interpret the results. It is almost more important to measure the parameters that affect indoor concentration than it is to measure the concentrations themselves.

  11. Predicting the combined effect of TiO{sub 2} nano-particles and welding input parameters on the hardness of melted zone in submerged arc welding by fuzzy logic

    Energy Technology Data Exchange (ETDEWEB)

    Aghakhani, Masood; Ghaderi, Mohammad Reza; Jalilian, Maziar Mahdipour; Derakhshan, Ali Ashraf [Razi University, Kermanshah (Iran, Islamic Republic of)

    2013-07-15

    Submerged arc welding (SAW) is a high-quality arc welding process used in heavy industries for welding thick plates. In this process, selecting appropriate values for the input parameters is required for high productivity and cost effectiveness. A very important weld quality characteristic affected by welding input parameters is the hardness of melted zone (HMZ). This paper reports the applicability of fuzzy logic (FL) to predict HMZ in the SAW process which is affected by the combined effect of TiO{sub 2} nano-particles and welding input parameters. The arc voltage, welding current, welding speed, contact tip-to-plate distance, and TiO{sub 2} nano-particles were used as input parameters and HMZ as the response to develop FL model. A five-level five-factor central composite rotatable design (CCRD) was used in the experiments to generate experimental data. Experiments were performed, and HMZs were measured. The predicted results from FL were compared with the experimental data. The correlation factor value obtained was 99.99% between the measured and predicted values of HMZ. The results showed that FL is an accurate and reliable technique for predicting HMZ because of its low error rate.

  12. Structural and Mössbauer studies of nanocrystalline Mn{sup 4+}-doped Li{sub 0.5}Fe{sub 2.5}O{sub 4} particles prepared by mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Widatallah, H. M., E-mail: hishammw@squ.edu.om; Al-Mabsali, F. N.; Al-Hajri, F. S. [Sultan Qaboos University, Physics Department, College of Science (Oman); Khalifa, N. O. [University of Khartoum, Physics Department, Faculty of Science (Sudan); Gismelseed, A. M.; Al-Rawas, A. D.; Elzain, M.; Yousif, A. [Sultan Qaboos University, Physics Department, College of Science (Oman)

    2016-12-15

    The structure and magnetic properties of spinel-related Mn{sup 4+}-doped Li{sub 0.5}Fe{sub 2.5}O{sub 4} nanocrystalline particles of the composition Li{sub 0.5}Fe{sub 2.25}Mn{sub 0.1875}O{sub 4}, prepared by milling a pristine sample for different times, were investigated. The average crystallite and particle size, respectively, decreased form ∼40 nm to ∼10 nm and ∼2.5 μm to ∼10 nm with increasing milling time from 0 h to 70 h. Rietveld refinement of the XRD data of the non-milled sample show the Mn{sup 4+} dopant ions to substitute for Fe{sup 3+} at the octahedral B-sites of the spinel-related structure. The Mössbauer spectra of the milled ferrites indicate that more particles turn superparamagnetic with increasing milling time. The Mössbauer data collected at 78 K suggest that while in the non-milled sample the Mn{sup 4+} ions substitute for Fe{sup 3+} at the octahedral B-sites, this is reversed as milling proceeds with doped Mn{sup 4+} ions, balancing Fe{sup 3+} vacancies and possibly Li{sup +} ions progressively migrate to the tetrahedral A-sites. This is supported by the slight increase observed in the magnetization of the milled samples relative to that of the non-milled one. The magnetic data suggest that in addition to the increasing superparamagentic component of the milled particles, thermal spin reversal and/or spin canting effects are possible at the surface layers of the nanoparticles.

  13. Relationship between Particle Hardness of LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} and its Electrochemical Stability at High Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jun Ho; Oh, Seung Mo [Seoul National University, Seoul (Korea, Republic of); Kim, Young Jun [Korea Electronic Technology Institute, Seongnam (Korea, Republic of); Kim, Jaekwang; Yoon, Songhun [Chung-Ang University, Seoul (Korea, Republic of)

    2016-08-15

    LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} was synthesized as a cathode material for lithium-ion batteries by coprecipitation and solid-state synthesis. The precursor prepared by coprecipitation was sintered at 950-1000 .deg. C for 10-15 h under air. A cathode material annealed at 950 .deg. C for 10 h (NMC950-10) has 81% capacity retention, whereas another cathode material at 1000 .deg. C for 15 h (NMC1000-15) has 85% capacity retention at the 80th cycle at a 60 .deg. C cycle test temperature. Cross-sectional images of pressed electrodes reveal that this difference results from different degrees of particle rupture. Image analysis shows that the percentages of particle rupture in NMC950-10 and NMC1000-15 were 44% and 20%, respectively. The measured particle hardness of the cathode material is quantitatively related to the number of ruptured particles in highly pressed electrodes. Therefore, the cathode material with higher particle hardness exhibits better cycle life performance in 60 .deg. C cell tests.

  14. High efficiency, narrow particle size distribution, sub-2 μm based macrocyclic glycopeptide chiral stationary phases in HPLC and SFC.

    Science.gov (United States)

    Barhate, Chandan L; Wahab, M Farooq; Breitbach, Zachary S; Bell, David S; Armstrong, Daniel W

    2015-10-22

    State of the art chiral chromatography still employs 3-5 μm bonded or immobilized chiral selectors in 10-25 cm columns. With the availability of 1.9 μm narrow particle size distribution (NPSD) silica, it is now possible to make ever shorter, high efficiency columns practical for sub-minute chiral separations. Three macrocyclic glycopeptides (teicoplanin, teicoplanin aglycone, and vancomycin) were bonded onto 1.9 μm NPSD particles. Such packed columns had ∼80% lower backpressure as compared to polydisperse (PD) 1.7 μm silica materials when using the same mobile phase. The decreased backpressure allowed for diminution of frictional heating and allowed for the use of the 1.9 μm NPSD particle based columns at high flow rates. The 1.9 μm NPSD particle based columns showed up to 190,000 plates m(-1) for chiral molecules and 210,000 plates m(-1) for achiral probes. Representative enantiomeric separations are shown for wide classes of compounds, including different types of amino acids, β-blockers, and pharmaceutically important heterocyclic compounds such as oxazolidinones. Applications in three liquid chromatography modes, namely, reversed phase, polar organic mode and normal phase chiral separations were shown with resolution values ranging from 1.5 to 5.7. Additionally, the same columns were used with supercritical fluid chromatography (SFC) for ultrafast separations. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Synthesis of Ni nanoparticles decorated SiO{sub 2}/TiO{sub 2} magnetic spheres for enhanced photocatalytic activity towards the degradation of azo dye

    Energy Technology Data Exchange (ETDEWEB)

    Mahesh, K.P.O., E-mail: kpomahesh@yahoo.com; Kuo, Dong-Hau, E-mail: dhkuo@mail.ntust.edu.tw

    2015-12-01

    Highlights: • Synthesis of SiO{sub 2} core and TiO{sub 2} sphere with uniform in shape and size. • Synthesis of Ni-SiO{sub 2}/TiO{sub 2} magnetic particles without the assistance of template and surfactant. • Characterization of Ni-SiO{sub 2}/TiO{sub 2} magnetic particles by PXRD, EDX, FE-SEM, TEM, UV–vis DRS and electrochemical impedance spectra (EIS). • Ni-SiO{sub 2}/TiO{sub 2} magnetic photocatalyst successfully degraded the AB 1 dye. • Prepared Ni-SiO{sub 2}/TiO{sub 2} photocatalyst is stable and reusable. - Abstract: Highly photocatalytic active Ni magnetic nanoparticles-decorated SiO{sub 2} core/TiO{sub 2} shell (Ni-SiO{sub 2}/TiO{sub 2}) particles have been prepared by the simultaneous hydrolysis and condensation of titanium tetra-isopropoxide on SiO{sub 2} sphere of ∼300 nm in size followed by the reduction of nickel chloride using hydrazine hydrate as a reducing agent. The crystalline nature, surface morphology, electrochemical impedance spectra and UV–vis diffuse reflectance spectra of the Ni-SiO{sub 2}/TiO{sub 2} magnetic spheres were characterized by PXRD, FE-SEM, TEM, EIS and UV–vis DRS. The Ni-SiO{sub 2}/TiO{sub 2} magnetic photocatalyst was used for the degradation of Acid Black 1 (AB 1) dye under UV irradiation. The effects of different concentrations of the Ni nanoparticles deposited on the SiO{sub 2}/TiO{sub 2} composite spheres for the photo-mineralization of AB 1 dye were analyzed. The results showed the Ni-SiO{sub 2}/TiO{sub 2} magnetic photocatalyst to be efficient and reusable.

  16. Structural, magnetic and optical characterization of Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} nano particles prepared by co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, Y.B., E-mail: ybkans@gmail.com [Department of Physics, Arumugam Pillai Seethai Ammal College, Tiruppattur 630211 (India); Saravanan, R. [Research Centre & PG Department of Physics, The Madura College, Madurai 625011 (India); Srinivasan, N. [Research Centre & PG Department of Physics, Thiagarajar College, Madurai 625009 (India); Praveena, K. [School of Physics, Univeristy of Hyderabad, Hyderabad 500046 (India); Sadhana, K. [Material Research Center, Indian Institute of Science, Bangalore 560012 (India)

    2016-12-01

    Bond strength values, between tetrahedral sites and octahedral sites atoms in the unit cell, are evaluated using maximum entropy method (MEM) for the Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} nano ferrite particles, prepared by co-precipitation method and sintered at 900 °C. The spinel structure is confirmed from the XRD analysis done using the Rietveld method. Substitution of zinc ion causes increase in lattice parameter value. Thermal behavior, morphology, magnetic properties and optical band gap energy values of the sample are determined by using thermogravimetric analysis and differential thermal analysis, scanning electron microscope, vibrating sample magnetometer and UV–VIS–NIR techniques respectively. Low value of saturation magnetization is attributed to the disorder in cation distribution.

  17. CO{sub 2} separation

    Energy Technology Data Exchange (ETDEWEB)

    Hakuta, Toshikatu [National Inst. of Materials and Chemical Research, Ibaraki (Japan)

    1993-12-31

    The climate change induced by CO{sub 2} and other greenhouse gases is probably the most serious environmental threat that mankind has ever experienced. Nowadays fossil fuels occupy the majority of the world commercial energy supply. Most nations will be dependent on fossil fuels even in the first half of the next century. Around 30 % of CO{sub 2} in the world is emitted from thermal power plants. Recovering CO{sub 2} from energy conversion processes and storing it outside the atmosphere is a promising option for the mitigation of global warming. CO{sub 2} fixation and storage include CO{sub 2} disposal into oceans and underground, and utilization of CO{sub 2}. CO{sub 2} separation process will be used in any CO{sub 2} storage system, and is estimated to consume almost half the energy of the total system. Research and development of highly efficient CO{sub 2} separation process is most important from the viewpoint of practical application of CO{sub 2} fixation system.

  18. Study of fine particles (PM{sub 2.5}) during the dry-hot time in the Toluca city; Estudio de las particulas finas (PM{sub 2.5}) durante la epoca seca-caliente en la ciudad de Toluca

    Energy Technology Data Exchange (ETDEWEB)

    Rosendo G, V. [ITT, 50000 Toluca (Mexico); Aldape U, F. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: vero_rosen2108@yahoo.com.mx

    2007-07-01

    The first obtained results of the analysis of the fine fraction particulate material (PM{sub 2.5}) samples collected in the Toluca City are presented. The samples analyzed are part of a more extensive campaign that contemplates the low project the one which one carries out this work and that it integrates three climatic times (dry-hot, of rains and dry-cold time) with the purpose of investigating the events of contamination in one complete year. The obtained results correspond to the dry-hot time and its include mainly the database starting from which the temporal variation graphs were obtained, the correlations among elements and the enrichment factor, as well as a multiple correlation analysis. Additionally the gravimetry was measured. Its are not observed significant episodes, however, it was found an element of the traces order, little common in other atmospheric studies as it is arsenic. From the gravimetry it was deduced that the air quality standard of fine particle, it does not violate. (Author)

  19. Fabrication of heterostructured Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} photocatalyst and efficient photodegradation of organic contaminants under visible-light

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Meng; Li, Shuangli; Yan, Tao; Ji, Pengge; Zhao, Xia; Yuan, Kun; Wei, Dong [School of Resources and Environment, University of Jinan, Jinan 250022 (China); Du, Bin, E-mail: dubin61@gmail.com [School of Resources and Environment, University of Jinan, Jinan 250022 (China); Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China)

    2017-07-05

    Highlights: • The product shows efficient activity in photodegradation of RhB, BPA, and phenol. • The BBOC-10 heterojunction exhibits the best activity under visible light. • Suppressed recombination of photo-generated carriers lead to the activity enhancement. - Abstract: Heterostructured Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} photocatalysts were fabricated by a facile one-pot hydrothermal method, in which melem served as the sacrificial reagent to supply carbonate anions. The as-synthesized Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} heterojunction catalysts were characterized by X-ray diffraction, UV–vis diffuse reflectance spectra, X-ray photoelectron spectroscopy, scanning electron microscope, and transmission electron microscope. The XRD patterns of Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} catalysts showed the distinctive peaks of Bi{sub 2}O{sub 2}CO{sub 3} and Bi{sub 2}O{sub 4}. The SEM and TEM results showed that the pure Bi{sub 2}O{sub 2}CO{sub 3} possessed large plate morphology, while Bi{sub 2}O{sub 4} were composed of various nanorods and particles. As for Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} heterojunction, it was obviously observed that Bi{sub 2}O{sub 4} nanorods and particles were grown on the surfaces of Bi{sub 2}O{sub 2}CO{sub 3} plates. The visible light driven photocatalytic activity of Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} heterojunction photocatalyst was evaluated by decomposing dyes, phenol, and bisphenol A in water. Compared with Bi{sub 2}O{sub 2}CO{sub 3} and Bi{sub 2}O{sub 4}, the Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 2}O{sub 4} photocatalysts have exhibited remarkable enhanced activity under visible light. The excellent activity can be mainly attributed to the enhanced separation efficiency of photo-generated carriers. Controlled experiments using different radical scavengers proved that ·O{sub 2}{sup −} and h{sup +} played the main role in decomposing organic pollutants. The results of this work would

  20. Nanostructured aluminium titanate (Al{sub 2}TiO{sub 5}) particles and nanofibers: Synthesis and mechanism of microstructural evolution

    Energy Technology Data Exchange (ETDEWEB)

    Azarniya, Abolfazl, E-mail: abolfazl_azarniya@mehr.sharif.ir [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11155-9466, Azadi Avenue, Tehran (Iran, Islamic Republic of); Azarniya, Amir, E-mail: a.azarnia91@gmail.com [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11155-9466, Azadi Avenue, Tehran (Iran, Islamic Republic of); Hosseini, Hamid Reza Madaah, E-mail: madaah@sharif.ir [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11155-9466, Azadi Avenue, Tehran (Iran, Islamic Republic of); Simchi, Abdolreza [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, Tehran (Iran, Islamic Republic of)

    2015-05-15

    In this study, aluminium titanate (AT) particles and nanofibers were synthesized through citrate sol gel and sol gel-assisted electrospinning methods in both nanostructured powder and nanofiber forms. The results of X-ray diffraction analysis, field-emission scanning electron microscopy and differential thermal analysis showed that the synthetic products benefit a nanostructured nature with a grain size less than 70 nm. The optimal values for time and temperature at which a roughly pure AT is attained were determined as 2 h and 900 °C, respectively. It was found that the sol gel precursor bears an amorphous structure till 700 °C and begins to be crystallized to alumina, anatase and AT at higher temperatures. Moreover, AT tends to decompose into rutile and alumina at temperatures higher than 900 °C and its degradation rate reaches a maximum at temperatures near to 1100 °C. In this synthesis, citric acid was used as a chelating agent for Al{sup 3} {sup +} and Ti{sup 4} {sup +} ions and it was shown that a low citric acid-to-metal cation ratio leads to larger numbers of nuclei during crystallization and smaller grain size. Finally, a model was suggested to describe the microstructural evolution of AT compound based on a nucleation and growth regime. - Graphical abstract: Display Omitted - Highlights: • We synthesized aluminium titanate ceramic in both powder and nanofiber forms. • The methods in use were citrate sol gel and sol gel-assisted electrospinning. • Powders and nanofibers bear a nanostructured nature with a grain size less than 70 nm. • A model is suggested to describe microstructural evolution of synthetic products.

  1. Attapulgite-CeO{sub 2}/MoS{sub 2} ternary nanocomposite for photocatalytic oxidative desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiazhang, E-mail: lixiazhang509@163.com [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory for Environment Functional Materials, Suzhou University of Science and Technology, Suzhou 215009 (China); W.M.Keck Center for Advanced Microscopy and Microanalysis, University of Delaware, Newark, DE 19716 (United States); Zhang, Zuosong [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Yao, Chao [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Lu, Xiaowang [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Zhao, Xiaobing [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory for Environment Functional Materials, Suzhou University of Science and Technology, Suzhou 215009 (China); Ni, Chaoying [W.M.Keck Center for Advanced Microscopy and Microanalysis, University of Delaware, Newark, DE 19716 (United States)

    2016-02-28

    Graphical abstract: - Highlights: • Novel attapulgite(ATP)-CeO{sub 2}/MoS{sub 2} ternary nanocomposites were fabricated. • ATP possessed outstanding adsorption property and enhanced the stability of the network structure. • CeO{sub 2}/MoS{sub 2} couples facilitated the separation of photo-induced electrons and holes. • Mass ratio of CeO{sub 2}/MoS{sub 2} influenced the photocatalytic oxidation desulfurization. - Abstract: Novel attapulgite(ATP)-CeO{sub 2}/MoS{sub 2} ternary nanocomposites were synthesized by microwave assisted assembly method. The structures of the nanocomposites were characterized by XRD, FT-IR, UV–vis, XPS and in situ TEM. The photocatalytic activities of ATP-CeO{sub 2}/MoS{sub 2} composites were investigated by degradating dibenzothiophene (DBT) in gasoline under visible light irradiation. The effect of the mass ratio of CeO{sub 2} to MoS{sub 2} on photocatalytic activity was investigated. The results indicate that the three-dimensional network structure is firmly constructed by ATP skeleton, CeO{sub 2} particles and MoS{sub 2} nanosheet which effectively increase the surface area of the composites and promote the separation of electrons and holes by resulting electronic transmission channels of multi-channel in space. The degradation rate of DBT can reach 95% under 3 h irradiation when the mass ratio of CeO{sub 2}/MoS{sub 2} is 4/10. A plausible mechanism for the photocatalytic oxidative desulfurization of this nanocomposite is put forward.

  2. Sol–gel hybrid membranes loaded with meso/macroporous SiO{sub 2}, TiO{sub 2}–P{sub 2}O{sub 5} and SiO{sub 2}–TiO{sub 2}–P{sub 2}O{sub 5} materials with high proton conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Yolanda, E-mail: castro@icv.csic.es [Instituto de Cerámica y Vidrio, Consejo Superior de Investigaciones Científicas (ICV-CSIC), Campus de Cantoblanco, 28049 Madrid (Spain); Mosa, Jadra, E-mail: jmosa@icv.csic.es [Instituto de Cerámica y Vidrio, Consejo Superior de Investigaciones Científicas (ICV-CSIC), Campus de Cantoblanco, 28049 Madrid (Spain); Aparicio, Mario [Instituto de Cerámica y Vidrio, Consejo Superior de Investigaciones Científicas (ICV-CSIC), Campus de Cantoblanco, 28049 Madrid (Spain); Pérez-Carrillo, Lourdes A.; Vílchez, Susana; Esquena, Jordi [Instituto de Química Avanzada de Cataluña, Consejo Superior de Investigaciones Científicas (IQAC-CSIC), CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona 18-26, 08034 Barcelona (Spain); Durán, Alicia [Instituto de Cerámica y Vidrio, Consejo Superior de Investigaciones Científicas (ICV-CSIC), Campus de Cantoblanco, 28049 Madrid (Spain)

    2015-01-15

    In this work, highly conductive hybrid organic–inorganic membranes loaded with SiO{sub 2}, TiO{sub 2}–P{sub 2}O{sub 5} and SiO{sub 2}–TiO{sub 2}–P{sub 2}O{sub 5} meso/macroporous particles were prepared via a sol–gel process. Meso/macroporous particles were incorporated to hybrid membranes, for improving water retention and enhancing electrochemical performance. These particles with a polymodal pore size distribution were prepared by templating in highly concentrated emulsions, the particles showed a specific surface area between 50 m{sup 2}/g (TiO{sub 2}–P{sub 2}O{sub 5}) and 300 m{sup 2}/g (SiO{sub 2}–TiO{sub 2}–P{sub 2}O{sub 5}). The particles were dispersed in a hybrid silica sol and further sprayed onto glass paper. The films were polymerized and sintered; those loaded with meso/macroporous particles had a homogenous distribution. High temperature proton conductivity measurements confirmed a high water retention. Conductivity of these materials is higher than that of Nafion{sup ®} at higher temperatures (120 °C) (2·10{sup −2} S/cm). This study provides processing guideline to achieve hybrid electrolytes for efficient conduction of protons due to their high surface area and porous structure. - Highlights: • Hybrid electrolyte with meso/macroporous particles were synthesized by sol–gel. • Depositions of hybrid solutions by spraying onto glass substrates were performed. • Proton conductivity was evaluated as a function of composition and porous structure.

  3. Improved photovoltaic efficiency on TiO{sub 2}/In{sub 2}S{sub 3} double layered electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, A-Young; Senthil, T.S.; Kwak, Byeong Sub; Kang, Misook, E-mail: mskang@ynu.ac.kr

    2015-01-15

    To enhance the photovoltaic efficiency of TiO{sub 2} multilayer, a scattering layer of In{sub 2}S{sub 3} particle is designed in dye-sensitized solar cell system. The SEM image of In{sub 2}S{sub 3} powder shows micro-sized 3D chrysanthemum-like shapes are formed by aggregation of wedge like nanosheets. The efficiency of the dye-sensitized solar cells assembled with In{sub 2}S{sub 3} scattering layer is higher than the DSSC assembled with double layered TiO{sub 2} electrode. The short-circuit current density increases approximately 21.65% over TiO{sub 2}/1.0 wt.% In{sub 2}S{sub 3}-DSSC and the incident photon-to-current conversion efficiency in the maximum peak also enhances about 17% compared to the DSSC assembled with double layered TiO{sub 2} electrode. Eventually, the maximum conversion efficiency obtained for TiO{sub 2}/1.0 wt.% In{sub 2}S{sub 3}-DSSC is 5.80%. This result indicates that the double layered TiO{sub 2}/In{sub 2}S{sub 3} electrode acts as a scattering layer of incident light path and that an increasing array of current density is obtained with more photons, which thus improves the quantum efficiency. - Highlights: • In{sub 2}S{sub 3} powder showed micro-sized 3D chrysanthemum-like shape. • In{sub 2}S{sub 3}-DSSCs exhibited the higher efficiencies than on the double layered TiO{sub 2}-DSSC. • The efficiency of TiO{sub 2}/1.0 wt.% In{sub 2}S{sub 3}-DSSC was approximately 5.80%. • TiO{sub 2}/1.0 wt.% In{sub 2}S{sub 3}-DSSC showed the slower recombination time than TiO{sub 2}/TiO{sub 2}-DSSC. • Electrons donated from dye-LUMO easily transferred to the conduction band of In{sub 2}S{sub 3}.

  4. Synthesis of monodisperse spherical core-shell SiO{sub 2}-SrAl{sub 2}Si{sub 2} O{sub 8}:Eu{sup 2+} phosphors by hydrothermal homogeneous precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Li Yidong; Xiao Liyuan; Liu Yingliang; Ai Pengfei; Chen Xiaobo, E-mail: tliuyl@jnu.edu.c [Department of Chemistry, Jinan University, Guangzhou 510632 (China)

    2010-08-15

    Nanocrystalline SrAl{sub 2}Si{sub 2} O{sub 8} :Eu{sup 2+} phosphor layers were coated on nonaggregated, monodisperse and spherical SiO{sub 2} particles using a hydrothermal homogeneous precipitation. After annealing at 1100 {sup 0}C, core-shell SiO{sub 2}-SrAl{sub 2} Si{sub 2} O{sub 8} :Eu{sup 2+} particles were obtained. They were characterized with x-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy and photoluminescence techniques. XRD analysis confirmed the formation of SiO{sub 2}-SrAl{sub 2} Si{sub 2} O{sub 8} :Eu{sup 2+} particles; it indicated that the SrAl{sub 2} Si{sub 2} O{sub 8} :Eu{sup 2+} shells on SiO{sub 2} particles consisted of hexagonal crystallites. The core-shell phosphors obtained are well-dispersed submicron spherical particles with a narrow size distribution. The thickness of the coated layer is approximately 20-40 nm. Under ultraviolet excitation (361 nm), the particles emit blue light at about 440 nm due to the Eu{sup 2+} ions in their shells.

  5. Radiolytic corrosion of uranium dioxide induced by He{sup 2+} localized irradiation of water: Role of the produced H{sub 2}O{sub 2} distance

    Energy Technology Data Exchange (ETDEWEB)

    Traboulsi, Ali [SUBATECH, UMR 6457, Ecole des Mines de Nantes, CNRS/IN2P3, Université de Nantes, 4, Rue Alfred Kastler, La Chantrerie BP 20722, 44307 Nantes Cedex 3 (France); Vandenborre, Johan, E-mail: johan.vandenborre@subatech.in2p3.fr [SUBATECH, UMR 6457, Ecole des Mines de Nantes, CNRS/IN2P3, Université de Nantes, 4, Rue Alfred Kastler, La Chantrerie BP 20722, 44307 Nantes Cedex 3 (France); Blain, Guillaume [SUBATECH, UMR 6457, Ecole des Mines de Nantes, CNRS/IN2P3, Université de Nantes, 4, Rue Alfred Kastler, La Chantrerie BP 20722, 44307 Nantes Cedex 3 (France); Humbert, Bernard [Institut de Matériaux Jean Rouxel, UMR 6502, Université de Nantes – CNRS, 2 rue de la Houssinnière, BP 32229, 44340 Nantes (France); Haddad, Ferid [SUBATECH, UMR 6457, Ecole des Mines de Nantes, CNRS/IN2P3, Université de Nantes, 4, Rue Alfred Kastler, La Chantrerie BP 20722, 44307 Nantes Cedex 3 (France); Cyclotron Arronax, 1 rue Arronax, CS 10112, 44817 Saint Herblain Cedex (France); Fattahi, Massoud [SUBATECH, UMR 6457, Ecole des Mines de Nantes, CNRS/IN2P3, Université de Nantes, 4, Rue Alfred Kastler, La Chantrerie BP 20722, 44307 Nantes Cedex 3 (France)

    2015-12-15

    The short-range (few μm in water) of the α-emitting from the spent fuel involves that the radiolytic corrosion of this kind of sample occurs at the solid/solution interface. In order to establish the role of localization of H{sub 2}O{sub 2} species produced by the He{sup 2+} particle beam in water from the surface, we perform UO{sub 2} radiolytic corrosion experiment with different distance between H{sub 2}O{sub 2} production area and UO{sub 2} surface. Then, in this work, the radiolytic corrosion of UO{sub 2} particles by oxidative species produced by {sup 4}He{sup 2+} radiolysis of water was investigated in open to air atmosphere. The dose rate, the localization of H{sub 2}O{sub 2} produced by water radiolysis and the grain boundaries present on the surface of the particles were investigated. UO{sub 2} corrosion was investigated by in situ (during irradiation) characterization of the solid surface, analysis of H{sub 2}O{sub 2} produced by water radiolysis and quantification of the uranium species released into the solution during irradiation. Characterization of the UO{sub 2} particles, surface and volume, was realized by Raman spectroscopy. UV–vis spectrophotometry was used to monitor H{sub 2}O{sub 2} produced by water radiolysis and in parallel the soluble uranium species released into the solution were quantified by inductively coupled plasma mass spectrometry. During the He{sup 2+} irradiation of ultra-pure water in contact with the UO{sub 2} particles, metastudtite phase was formed on the solid surface indicating an oxidation process of the particles by the oxidative species produced by water radiolysis. This oxidation occurred essentially on the grain boundaries and was accompanied by migration of soluble uranium species (U(VI)) into the irradiated solution. Closer to the surface the localization of H{sub 2}O{sub 2} formation, higher the UO{sub 2} oxidation process occurs, whereas the dose rate had no effect on it. Simultaneously, closer to the surface

  6. Impact of ignition temperature on particle size and magnetic properties of CoFe{sub 2}O{sub 4} nanoparticles prepared by self-propagated MILD combustion technique

    Energy Technology Data Exchange (ETDEWEB)

    Kaliyamoorthy, Venkatesan; Rajan Babu, D., E-mail: drajanbabu@vit.ac.in; Saminathan, Madeswaran

    2016-11-15

    We prepared nanocrystalline CoFe{sub 2}O{sub 4} by changing its ignition temperatures, using moderate and intense low-oxygen dilution (MILD) combustion technique. The effect of ignition temperature on the particle size and its magnetic behavior was investigated by HR-TEM and VSM respectively. We observed a vast change in the structural behavior and the magnetic properties of the prepared samples. X-ray diffraction studies revealed that the resultant samples had single phase with different grain sizes from 23±5 nm to 16±5 nm, which was understood by observing the growth of the grains through heat released from the combustion reaction. FE-SEM analysis showed high porosity with heterogeneous distribution of the pore size based on the adiabatic temperature and EPMA analysis, which confirmed the elemental compositions of the prepared samples. The saturation magnetization values measured at room temperature, employing vibrating sample magnetometer (VSM) decreased gradually from 50 to 34 emu/g when the ignition temperature was increased from 243 °C to 400 °C. Some of Fe ions on the B sites moved periodically to the A sites because of quenching treatment. The presence of Fe{sup 2+} ions in the existing ferrite structure ruled the magnetic behavior of the sample, as confirmed by the Mössbauer analysis. - Highlights: • CoFe{sub 2}O{sub 4} magnetic nanoparticles were prepared by MILD combustion technique. • Structural behavior and magnetic properties were changed by ignition temperature. • Formation of ferrite complex was confirmed by using FT-IR spectroscopy. • FE-SEM image confirmed the combustion nature by exhibiting the pores and voids. • The cationic distributions were investigated by the Mössbauer analysis.

  7. Synthesis of CeO{sub 2}-coated SiO{sub 2} nanoparticle and dispersion stability of its suspension

    Energy Technology Data Exchange (ETDEWEB)

    Song Xiaolan [Department of Inorganic Materials, School of Resources Processing and Bioengineering, Central South University, 410083 Changsha (China)], E-mail: xlsong@hnu.cn; Jiang Nan; Li Yukun; Xu Dayu; Qiu Guanzhou [Department of Inorganic Materials, School of Resources Processing and Bioengineering, Central South University, 410083 Changsha (China)

    2008-07-15

    SiO{sub 2} nanoparticle prepared through sol-gel method was directly coated with CeO{sub 2} by means of chemical precipitation technique. X-ray diffraction (XRD), differential scanning calorimetry/thermogravimetry (DSC/TG), infrared (IR) spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive analysis of X-ray (EDAX) were used to characterize the CeO{sub 2}-coated SiO{sub 2} nanoparticle. XRD patterns showed that the core region of the composite particles was amorphous SiO{sub 2}, and the shell region was fluorite-structured CeO{sub 2}. IR results indicated that the coating of the SiO{sub 2} nanoparticle with CeO{sub 2} evidently induced the presence of new bands at 960 cm{sup -1}, due to the vibration of Ce-O-Si. Isoelectric point of the CeO{sub 2}-coated SiO{sub 2} nanoparticle was about 5.6, which displayed a significant shift toward pure CeO{sub 2}. SEM and TEM micrographs revealed that CeO{sub 2}-coated SiO{sub 2} nanoparticle showed a spherical morphology with the diameter about 300 nm and a uniform particle size. Dispersion behaviors of CeO{sub 2}-coated SiO{sub 2} nanoparticle under different conditions were studied in water suspension by investigating its zeta potential and absorbance. The results indicated that zeta potential was higher when pH value was about 10, corresponding to better dispersion stability. The dispersion effect of ultrasonic wave on CeO{sub 2}-coated SiO{sub 2} nanoparticle was markedly superior compared with mechanical stirring. The zeta potential grew up evidently with the increasing of sodium dodecyl benzene sulfonate (SDBS) and poly ethylene glycol (PEG) 4000 concentration. A suspension with CeO{sub 2}-coated SiO{sub 2} at 0.02 wt.% was added in 0.05 g l{sup -1} anionic surfactant SDBS, and its pH value was adjusted within the range of 10-10.5. In this condition, the stable suspension without sedimentation time was successfully obtained.

  8. Effects of SO sub 2 , SO sub 2 +NO sub 2 and SO sub 2 +NO sub 2 +O sub 3 on the CO sub 2 /H sub 2 O gas exchange of forest soil vegetation. Die Wirkungen von SO sub 2 , SO sub 2 +NO sub 2 und SO sub 2 +NO sub 2 +O sub 3 auf den CO sub 2 /H sub 2 O-Gaswechsel der Waldbodenvegetation

    Energy Technology Data Exchange (ETDEWEB)

    Both, R.; Steubing, L.; Fangmeier, A. (Giessen Univ. (Germany, F.R.). Inst. fuer Pflanzenoekologie)

    1989-01-01

    The ground vegetation of a beech forest was fumigated with sulphur dioxide (300 {mu}g SO{sub 2}/m{sup 3}), nitrogen dioxide (100 {mu}g NO{sub 2}/m{sup 3}) and ozone (200 {mu}g O{sub 3}/m{sup 3}) in transportable open-top chambers for four hours weekly. The pollutants were applied in three different treatments: SO{sub 2} alone, SO{sub 2} + NO{sub 2} and SO{sub 2} + NO{sub 2} + O{sub 3}. Ambient air plots served as controls. The CO{sub 2}/H{sub 2}O gas exchange was measured in four species, Allium ursinum L., Melica uniflora Retz., Oxalis acetosella L.; Viola reichenbachiana Jord., during the fumigations. The response to the fumigations was dependent on species, on treatment, and on PAR. SO{sub 2} alone reduced transpiration and photosynthesis of Allium ursinum. SO{sub 2} + NO{sub 2} caused depressions of these parameters in Oxalis acetosella and Viola reichenbachiana, but not in Allium ursinum and Melica uniflora. Treatments with SO{sub 2} + NO{sub 2} + O{sub 3} decreased the gas exchange of all investigated species. The variability of the response was higher at low (ambient) PAR-values (1-30{mu}E/m{sup 2*}s). Thus, significant differences between fumigated and control plants were only detected by comparing light saturation curves. (orig.).

  9. Fabrication of Ag{sub 2}O/TiO{sub 2} with enhanced photocatalytic performances for dye pollutants degradation by a pH-induced method

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Hai-Tao, E-mail: renhaitaomail@163.com; Yang, Qing

    2017-02-28

    Highlights: • Ag{sub 2}O/TiO{sub 2} was synthesized by a pH-induced chemical precipitation method. • Ag{sub 2}O/TiO{sub 2} showed good activities in the photocatalytic degradation of methyl orange. • Hydroxyl radicals played the predominant role in methyl orange photodegradation. - Abstract: Ag{sub 2}O/TiO{sub 2} composites synthesized in this study were applied into the photocatalytic degradation of methyl orange (MO) under UV and visible light irradiation. X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscope analysis demonstrated that Ag{sub 2}O nanoparticles were well distributed on the surface of TiO{sub 2} and the heterostructure of Ag{sub 2}O/TiO{sub 2} was formed. Compared with the pure TiO{sub 2} and Ag{sub 2}O, the 3% and 50% Ag{sub 2}O/TiO{sub 2} composite displayed much higher photocatalytic activities in MO degradation under UV and visible light irradiation, respectively. The degradation rate constant of 50% composite was 0.01508 min{sup −1} under visible light, which was almost 20.1 and 1.2 times more than that of the pure TiO{sub 2} and Ag{sub 2}O, respectively. Moreover, the formation of Ag(0) on the surface of Ag{sub 2}O under illumination contributed to the high stability of Ag{sub 2}O/TiO{sub 2} photocatalysts. It was also found that hydroxyl radicals during the photocatalytic process played the predominant role in MO degradation. The enhanced photochemical activities were attributed to the formation of the heterostructure between Ag{sub 2}O and TiO{sub 2}, the strong visible light absorption and the high separation efficiency of photogenerated electron–hole pairs resulted from the highly dispersed Ag{sub 2}O particles.

  10. Green ultra-fast high-performance liquid chromatographic method using a short narrow-bore column packed with fully porous sub-2 μm particles for the simultaneous determination of selected pharmaceuticals as surface water and wastewater pollutants.

    Science.gov (United States)

    Shaaban, Heba; Górecki, Tadeusz

    2013-01-01

    Fast separations are very desirable in laboratories that analyze large numbers of samples per day or those needing short turn-around times. Traditional HPLC methods using conventional stationary phases and standard column dimensions require significant amounts of organic solvents and generate large volumes of waste. With growing awareness about the environment, the development of green technologies has been receiving increasing attention. In this work, a very fast green analytical method based on LC-UV using a short narrow bore column packed with fully porous sub-2 μm particles has been developed for simultaneous determination of nine pharmaceuticals in wastewater and surface water. The chromatographic separation was optimized in order to achieve short analysis time and good resolution for all analytes in a single run. All analytes could be separated in 1 min with good resolution. Sample preparation was executed by solid phase extraction using Oasis HLB cartridges. The method developed was validated based on parameters such as linearity, precision, accuracy, detection, and quantification limits. The recovery ranged from 70.9 to 92.5% with SDs not higher than 5.4%, except for acetaminophen and sulphanilamide. LODs ranged from 0.6-2.5 μg/L, while the LOQs were in the range 2-8 μg/L. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Enhanced photocatalytic hydrogen evolution activity of CuInS{sub 2} loaded TiO{sub 2} under solar light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Changjiang [Department of Chemistry, Huangshan University, Huangshan 245041 (China); Xi, Zhenhao; Fang, Wenzhang; Xing, Mingyang [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Zhang, Jinlong, E-mail: jlzhang@ecust.edu.cn [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Department of Chemistry, Tsinghua University, Beijing 100084 (China)

    2015-03-15

    In this paper, p–n type CuInS{sub 2}/TiO{sub 2} particles were prepared in ethylenediamine by the solvothermal method. The microstructural properties of the synthesized p–n type catalysts were characterized by X-ray diffraction (XRD) in order to confirm the existence of crystalline CuInS{sub 2} on the surface of TiO{sub 2}, which was also confirmed by X-ray photoelectron spectroscopy (XPS). Transmission electron microscopy (TEM) images provided the detailed morphological properties about the CuInS{sub 2}/TiO{sub 2} heterostructure. UV–vis diffuse reflectance spectroscopy (UV–vis DRS) was used to investigate the optical properties of the CuInS{sub 2}/TiO{sub 2} particles. The DRS results indicated that both the p–n type structure and CuInS{sub 2} acting as a sensitizer can enhance significantly the absorption of UV and visible light. The photocatalytic activities of the CuInS{sub 2}/TiO{sub 2} particles were evaluated by hydrogen evolution reactions using Xe-lamp irradiation as a simulated solar light source. The greatly enhanced photocatalytic activity of hydrogen evolution under simulated solar light is about ~7 fold higher than that of pure commercial TiO{sub 2} (Degussa P25). - Graphical abstract: The heterojunction structure of CuInS{sub 2}/TiO{sub 2} promoted the efficiency of photoinduced charge carrier transfer and highly inherited the recombination of activated electrons and holes. - Highlight: • CuInS{sub 2}/TiO{sub 2} was prepared by a one-step solvothermal method. • 2.5% CuInS{sub 2}/TiO{sub 2} has the highest activity and keeps the activity stable. • Heterojunction structure of sample promoted the separation of electrons and holes.

  12. Sol–gel combustion synthesis, particle shape analysis and magnetic properties of hematite (α-Fe{sub 2}O{sub 3}) nanoparticles embedded in an amorphous silica matrix

    Energy Technology Data Exchange (ETDEWEB)

    Kopanja, Lazar [Faculty of Technology and Metallurgy, University of Belgrade, Belgrade (Serbia); Milosevic, Irena [Laboratoire CSPBAT, UMR 7244 CNRS Université Paris 13, 93017 Bobigny Cedex (France); Panjan, Matjaz [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Damnjanovic, Vesna [Department of Physics, University of Belgrade, Faculty of Mining and Geology, Belgrade (Serbia); Tadic, Marin, E-mail: marint@vinca.rs [Condensed Matter Physics Laboratory, Vinca Institute, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia)

    2016-01-30

    Graphical abstract: - Highlights: • Hematite nanoparticles are synthesized by using sol–gel combustion synthesis method. • The SQUID measurements show blocking temperature T{sub B} = 27 K and superparamagnetism. • TEM measurements show spherical particles and narrow size distribution. • The sample did not exhibit the Morin transition. • The magnetic moment μ{sub p} = 195 μ{sub B} and diameter d = 5 nm were determined. - Abstract: We report the synthesis and magnetic properties of hematite/amorphous silica nanostructures. Raman spectroscopy showed the formation of a hematite phase. A transmission electron microscopy (TEM) revealed spherically shaped hematite nanoparticles, well-dispersed in an amorphous silica matrix. In order to quantitatively describe morphological properties of nanoparticles, we use the circularity of shapes as a measure of how circular a shape is. Diameters of about 5 nm and a narrow size distribution of nanoparticles are observed. The obtained hematite nanoparticles exhibit superparamagnetic properties at room temperature (SPION). The sample does not display the Morin transition. The FC hysteresis loop at 5 K has shown an exchange bias effect. These results have been compared to those previously reported for α-Fe{sub 2}O{sub 3}/SiO{sub 2} nanosystems in the literature. These comparisons reveal that the sol–gel combustion method yields hematite nanoparticles with a higher magnetization and magnetic moment. These data indicate the existence of an additional factor that contributes to magnetization. We suggest that the increased magnetization is due to an increased number of the surface spins caused by the breaking of large numbers of exchange bonds between surface atoms (disordered structure). This leads to an increase in the magnetic moment per a hematite nanoparticle and an exchange bias effect. We have concluded that the combustion-related part of this synthesis method enhances surface effects, i.e. it promotes the breaking of

  13. Room-temperature structure of La sub 2 O sub 2 S sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Ostorero, J. (Centre National de la Recherche Scientifique, 92 - Meudon-Bellevue (France). Lab. de Magnetisme et d' Optique des Solides); Leblanc, M. (Le Mans Univ., 72 (France). Lab. des Fluorures)

    1990-08-15

    Lanthanum oxide sulfide La{sub 2}O{sub 2}S{sub 2}, M{sub r}=373.947, orthorhombic, Cmca, a=13.215 (2), b=5.943 (1), c=5.938 (1) A, V=466.3 (2) A{sup 3}, Z=4, D{sub x}=5.32 Mg m{sup -3}, Mo K{alpha}, {lambda}=0.71069 A, {mu}=18.87 mm{sup -1}, F(000)=648, R=0.017, 582 unique observed reflections, flux growth, data corrected for twinning of the crystal. The structure is built from infinitive layers of LaO{sub 4}S{sub 4} square antiprisms connected by edges; these layers share either oxygen or disulfide common planes. Short S-S distances (d=2.103 (2) A) correspond to S{sub 2}{sup 2-} entities. (orig.).

  14. Na{sub 2}O-B{sub 2}O{sub 3}-SiO{sub 2} glass modified by Al{sub 2}O{sub 3}, TiO{sub 2}, ZrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Procyk, B.; Stoch, L.; Dabrowska, A.; Haniuk, I. [Akademia Gorniczo-Hutnicza, Cracow (Poland)

    1993-12-31

    The Na{sub 2}O-B{sub 2}O{sub 3}-SiO{sub 2} system with additions Al{sub 2}O{sub 3}, TiO{sub 2}, ZrO{sub 2} was examined. The conditions of thermal and chemical treatment necessary to obtain porous glasses were optimized. Their structure and basic physicochemical properties were investigated. (author). 4 refs, 5 figs, 1 tab.

  15. Environmental application of millimetre-scale sponge iron (s-Fe{sup 0}) particles (IV): New insights into visible light photo-Fenton-like process with optimum dosage of H{sub 2}O{sub 2} and RhB photosensitizers

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Yongming, E-mail: juyongming@scies.org [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Innovative Laboratory for Environmental Functional Materials and Environmental Applications of Microwave Irradiation, South China Subcenter of State Environmental Dioxin Monitoring Center, Guangzhou 510655 (China); Guangdong Key Laboratory of Agro-Environment Integrated Control, South China Institute of Environmental Sciences, Guangzhou 510655 (China); Yu, Yunjiang, E-mail: yuyunjiang@scies.org [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Wang, Xiaoyan; Xiang, Mingdeng; Li, Liangzhong [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Deng, Dongyang [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Innovative Laboratory for Environmental Functional Materials and Environmental Applications of Microwave Irradiation, South China Subcenter of State Environmental Dioxin Monitoring Center, Guangzhou 510655 (China); Guangdong Key Laboratory of Agro-Environment Integrated Control, South China Institute of Environmental Sciences, Guangzhou 510655 (China); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering (DBCEE), University of Cincinnati, Cincinnati, Ohio, 45221-0012 (United States)

    2017-02-05

    Highlights: • Synergistic action of Rhodamine B (RhB), visible light, H{sub 2}O{sub 2} and s-Fe{sup 0} is essential. • The complexes of RhB and Fe{sup 3+} eject one electron via ligand-to-metal charge-transfer. • RhB assists the photo-Fenton-like removal of tetrabromobisphenol A (TBBPA). - Abstract: In this study, we firstly develop the photo-Fenton-like system with millimetric sponge iron (s-Fe{sup 0}), H{sub 2}O{sub 2}, visible light (vis, λ ≥ 420 nm) and rhodamine B (RhB), and present a comprehensive study concerning the mechanism. Thus, we investigate (1) the adsorption of RhB onto s-Fe{sup 0}, (2) the photo-Fenton-like removal of RhB over iron oxides generated from the corrosion of s-Fe{sup 0}, (3) the homogeneous photo-Fenton removal of RhB over Fe{sup 2+} or Fe{sup 3+}, (4) the Fe{sup 3+}-RhB complexes, and (5) the photo-Fenton-like removal of tetrabromobisphenol A (TBBPA). The results show that neither the adsorption process over s-Fe{sup 0} nor the photo-Fenton-like process over FeOOH, Fe{sub 3}O{sub 4} and Fe{sub 2}O{sub 3}, achieved efficient removal of RhB. For comparison, in homogeneous photo-Fenton process, the presence of Fe{sup 3+} ions, rather than Fe{sup 2+} ions, effectively eliminated RhB. Furthermore, the UV–vis spectra showing new absorbance at ∼ 285 nm indicate the complexes of RhB and Fe{sup 3+} ions, adopting vis photons to form excited state and further eject one electron via ligand-to-metal charge-transfer to activate H{sub 2}O{sub 2}. Additionally, efficient TBBPA removal was obtained only in the presence of RhB. Accordingly, the s-Fe{sup 0}– based photo-Fenton-like process assisted with dyestuff wastewater is promising for removing a series of persistent organic pollutants.

  16. Thermodynamic study of BaCuO[sub 2] and BaCu[sub 2]O[sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Shimpo, Ryokichi; Nakamura, Yasushi (Univ. of Tokyo (Japan). Faculty of Engineering)

    1994-06-01

    The Gibbs energy changes for the syntheses of the interceramic compounds of BaCuO[sub 2] and BaCu[sub 2]O[sub 2] were investigated as a basic study in the Y-Ba-Cu-O system that includes a superconductor, YBa[sub 2]Cu[sub 3]O[sub 6.5+x]. For the compound BaCuO[sub 2], thermogravimetry with CO[sub 2[minus

  17. Enhancement of the luminescent intensity of the green emitting Gd{sub 2}O{sub 2}CO{sub 3}:Tb phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Mayama, Yuhei; Masui, Toshiyuki; Koyabu, Kazuhiko [Department of Applied Chemistry, Faculty of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Imanaka, Nobuhito [Department of Applied Chemistry, Faculty of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)], E-mail: imanaka@chem.eng.osaka-u.ac.jp

    2008-02-28

    A new synthesis route to prepare well-crystallized hexagonal rare earth oxycarbonates, II-RE{sub 2}O{sub 2}CO{sub 3} (RE = La, Gd, and Y) in a single phase, has been established by a simple flux method. The precursor obtained by calcination of corresponding acetates was mixed with a 0.476Li{sub 2}CO{sub 3}-0.270Na{sub 2}CO{sub 3}-0.254K{sub 2}CO{sub 3} eutectic mixture and heated in a pure CO{sub 2} (100%) atmosphere to obtain Eu{sup 3+}- or Tb{sup 3+}-doped II-RE{sub 2}O{sub 2}CO{sub 3} (RE = La, Gd, and Y) phosphors. Although the particle size of the oxycarbonate phosphors was in a submicron scale, they showed high emission intensities. The highest emission intensity was obtained successfully by changing the gas composition from 10%CO{sub 2}-90%N{sub 2} to pure CO{sub 2} and by optimizing the flux treatment temperature, holding the particle size in a submicron scale. The maximum emission intensity was obtained at the composition of Gd{sub 2}O{sub 2}CO{sub 3}:15 at.%Tb{sup 3+}, where it was 111% of that of a commercial LaPO{sub 4}:Ce{sup 3+},Tb{sup 3+} phosphor.

  18. Synthesis, characterization and optimization of photocatalytic activity of TiO{sub 2}/ZrO{sub 2} nanocomposite heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Pirzada, Bilal Masood; Mir, Niyaz A.; Qutub, Nida; Mehraj, Owais; Sabir, Suhail, E-mail: drsuhailsabir@gmail.com; Muneer, M.

    2015-03-15

    Graphical abstract: - Highlights: • TiO{sub 2}/ZrO{sub 2} nanocomposite was synthesized via hybrid sol–gel method. • Photocatalytic efficiency was found to be higher than Degussa P25. • The optimum loading amount of ZrO{sub 2} on TiO{sub 2} was found to be 6.0 molar%. • The synthesized nanocomposite showed enhanced stability. - Abstract: Titanium dioxide/zirconium dioxide nanocomposites were synthesized using a simple and modified sol–gel method. The synthesized particles were characterized through SEM, TEM, XRD, and DTA/TGA. SEM analysis shows micrographs with irregular and sharp edged particles. TEM analysis shows spherical particles of average diameter 10.5 nm. Tetragonal structure of TiO{sub 2}/ZrO{sub 2} nanocomposite particles with stabilized anatase phase was confirmed by XRD studies. The average crystallite size was calculated from XRD, using Scherrer's formula. Band gap was calculated from the DRS spectra using Kubelka-Munk function and Photoluminescence (PL) was done to study the recombination rate of charge carriers. Results showed a considerable increase in band gap on ZrO{sub 2} addition and subsequent decrease in recombination rate. Impedance study showed a significant decrease in dielectric characteristics on ZrO{sub 2} addition. Photocatalytic activity of the synthesized catalysts was studied by degradation of an azo-dye, Ponceau BS, using ultra-violet source of light. Optimum activity was observed on 6.0% ZrO{sub 2} loading.

  19. Investigation of superior electro-optical properties of SnO{sub 2}/SiO{sub 2} nanocomposite over its individual counterpart SnO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Naveen Kumar, P.; Sahaya Selva Mary, J.; Chandrakala, V.; Jothi Jeyarani, W.; Merline Shyla, J., E-mail: jmshyla@gmail.com

    2017-06-01

    A comparative investigation of SnO{sub 2}/SiO{sub 2} nanocomposite with SnO{sub 2} nanoparticles has been conducted in the present study with the intent of learning the probable enhancement of the properties of the nanocomposite over those of the bare nanoparticles which has not been widely reported before. SnO{sub 2} nanoparticles and SnO{sub 2}/SiO{sub 2} nanocomposite have been synthesized via the facile and versatile sol-gel method. The samples were characterized with X-Ray Diffraction (XRD), High Resolution Scanning Electron Microscopy (HRSEM), Brunauer Emmett Teller (BET) studies, Fourier Transform Infra-Red spectroscopy (FT-IR), UV–Visible (UV–Vis) spectroscopy and Field-dependent photo conductivity technique for the evaluation of their crystallite size, structure & morphology, surface, chemical, optical and electrical properties respectively. Scherrer’s equation was used to determine the crystallite size of the as-synthesized samples from the XRD data. The particle size of SnO{sub 2}/SiO{sub 2} nanocomposite as observed through HRSEM was found to be reduced when compared with the bare SnO{sub 2} nanoparticles suggesting a possible increase in the optical band gap of the former which has been further confirmed in the optical studies. The surface area of SnO{sub 2}/SiO{sub 2} nanocomposite revealed a remarkable enrichment by approximately 5 folds in comparison with that of SnO{sub 2} nanoparticles which suggests an enhancement in its corresponding optical and electrical properties. The SnO{sub 2}/SiO{sub 2} nanocomposite recorded appreciated values of field-dependent photo and dark currents with several folds of augmentation thereby qualifying as an efficient photoconducting material. Attributed with an improved surface area and increased photoconducting nature, the SnO{sub 2}/SiO{sub 2} nanocomposite could be presented as an excellent photoanode material for nanomaterials based Dye Sensitized Solar Cells (DSSCs). - Highlights: • SnO{sub 2}/SiO{sub 2

  20. Band structure of superconducting MgB sub 2 and isostructural CaGa sub 2 , AgB sub 2 , AuB sub 2 , ZrBe sub 2 and HfBe sub 2

    CERN Document Server

    Shein, I R; Ivanovskij, A L

    2001-01-01

    The analysis of the zonal structure of the MgB sub 2 mean-temperature superconductor is carried out. The MgB sub 2 quasi-two-dimensional structure is one of its important features. The comparison of the MgB sub 2 zonal structure and the ZrBe sub 2 , HfBe sub 2 and CaGa sub 2 isostructural hexagonal phases is carried out. The zonal structure calculations are accomplished through the Muffin-Tin self-coordinated full-potential linear method. The factors, responsible for the MgB sub 2 superconducting properties, are analyzed. The Ag and Au hypothetical diborides are considered

  1. Comparison of wound healing using the CO2 laser at 10.6 microm and 9.55 microm.

    Science.gov (United States)

    Converse, G M; Ries, W R; Reinisch, L

    2001-07-01

    The wound healing characteristics of incisions made with the short pulsed CO2 laser tuned to 9.55 microm versus the traditional 10.6 microm were investigated. Previous studies have shown that at 9.55 microm, collagen is targeted more selectively than at 10.6 microm, which results in decreased acute thermal injury patterns. This study investigates the difference in wound healing over time between lasers and compares laser incisions with cold knife techniques. Randomized controlled trial using a porcine model. Tissue from 10.6-microm and 9.55-microm incisions of 10 piglets was evaluated with histological analysis and tensiometry at 3, 7, 14, and 21 days postoperatively. A Bonferroni-Dunn corrected analysis of variance analysis at a 95% significance level was used to compare the effect of wavelength. The results demonstrate that although knife incisions are consistently stronger than laser incisions, the 9.55-microm CO2 laser incisions are no stronger than incisions made with the conventional 10.6-microm laser. Furthermore, histological analysis shows no difference in lateral thermal damage between lasers at 3, 7, 14, and 21 days postoperatively. The progression of collagen formation and inflammation does not differ over time. This study of wound healing using a porcine model demonstrates that the 9.55-microm CO2 laser does not demonstrate an improvement in wound healing over the traditional 10.6-microm CO2 laser. These results may be secondary to the common explosive vaporization mechanism produced by both lasers in the infrared spectrum.

  2. Preparation of transparent fluorocarbon/TiO{sub 2}-SiO{sub 2} composite coating with improved self-cleaning performance and anti-aging property

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jianping, E-mail: zf161162@163.com; Tan, Zhongyuan; Liu, Zhilei; Jing, Mengmeng; Liu, Wenjie; Fu, Wanli

    2017-02-28

    Graphical abstract: Semicrystalline colloidal particles of TiO{sub 2}-SiO{sub 2} composite oxide were prepared via a sol-gel approach and annealed by a microwave heating treatment. The fabricated fluorocarbon/TiO{sub 2}-SiO{sub 2} composite coatings are transparent, exhibit a highly stable and excellent hydrophilicity, an improved photocatalytic activity and outstanding self-cleaning performance. What’s more, the composite coatings display an excellent anti-aging performance toward UV irradiation. These findings indicate that the fluorocarbon/TiO{sub 2}-SiO{sub 2} composite coatings could be potentially used for outdoor applications. - Highlights: • Semicrystalline colloidal particles of TiO{sub 2}-SiO{sub 2} composite oxide presenting a particle size of 6–10 nm were prepared via a sol-gel approach and annealed by microwave heating method. • The fabricated transparent fluorocarbon/TiO{sub 2}-SiO{sub 2} composite coatings exhibited a superior hydrophilicity, an improved photocatalytic activity and excellent self-cleaning performance. • The fluorocarbon/TiO{sub 2}-SiO{sub 2} composite coatings exhibited an excellent anti-aging performance toward UV irradiation, rendering it quite suitable for outdoor applications. - Abstract: This work reports a facile method to fabricate transparent self-cleaning fluorocarbon coatings filled by semicrystalline colloidal particles of TiO{sub 2}-SiO{sub 2} composite oxide presenting a particle size ranging from 6 to 10 nm. Anatase-TiO{sub 2} crystallites were successfully obtained after microwave heating treatment of the TiO{sub 2}-SiO{sub 2} colloidal particles as confirmed by XRD, TEM and FTIR measurements. The fluorocarbon/TiO{sub 2}-SiO{sub 2} composite coatings exhibited a superior hydrophilicity and an improved photocatalytic activity in contrast to the TiO{sub 2}-filled coatings. In particular, a water contact angle (WCA) value of 4.5° and a decolorization ratio relative to methyl orange as high as 96.0% were

  3. SiO{sub 2}@SnO{sub 2}/graphene composite with a coating and hierarchical structure as high performance anode material for lithium ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xingfa; Zhang, Haiyan, E-mail: hyzhang@gdut.edu.cn; Chen, Yiming; Li, Na; Li, Yunyong; Liu, Liying

    2016-08-25

    In order to ease the agglomeration and huge volume change of SnO{sub 2} particles, SnO{sub 2} nanoparticles were usually anchored on reduced graphene oxide (rGO) and used as anode materials for lithium ion batteries. Unfortunately, graphene sheets tended to overlap with adjacent ones and SnO{sub 2} nanoparticles still suffered from agglomeration and huge volume changes to some extent. In this paper, a composite SiO{sub 2}@SnO{sub 2}/rGO with coating and hierarchical structure was synthesized by a facile hydrothermal method. SnO{sub 2} nanoparticles mono-dispersed on the surface of rGO sheets and SiO{sub 2} spheres, while the SiO{sub 2}@SnO{sub 2} spheres were imbedded in the layers of rGO, which was in favor of alleviating the overlapping of graphene sheets and could make large spacious room to accommodate the huge volume changes of SnO{sub 2} nanoparticles. SiO{sub 2}@SnO{sub 2}/rGO composite also displayed good electrochemical performance. In the first charge/discharge cycle, the SiO{sub 2}@SnO{sub 2}/rGO electrode exhibited a large discharge capacity of 1548 mA h g{sup −1} at a current density of 100 mA g{sup −1} and it still retained a discharge capacity of about 600 mA h g{sup −1} after 100 cycles. - Highlights: • Anodes fabricated by using activated carbon have the highest fracture strength. • SnO{sub 2} nanoparticles are mono-dispersed on the surface of rGO sheets and SiO{sub 2} spheres. • The hierarchical structure SiO{sub 2}@SnO{sub 2}/rGO shows a good electrochemical performance.

  4. Ignition and combustion characteristics of different rank coals in O{sub 2}/CO{sub 2} environments

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yuegui; Chu, Wei; Gu, Guangjin; Xu, Yangyang [Shanghai Jiao Tong Univ. (China). Inst. of Thermal Energy Engineering; Wendt, Jost O.L. [Utah Univ., Salt Lake City, UT (United States). Dept. of Chemical Engineering

    2013-07-01

    Previous works on flame stability and stand-off distance under oxy-coal combustion conditions has been conducted with a co-axial turbulent diffusion burner for different rank coals in a 100 kW pulverized coal test rig at the University of Utah. The pilot-scale results indicate that oxygen partial pressure and coal compositions have a significant effect on the ignition and flame stability of coal particles in the oxy-coal combustion. The aim of the present paper is to investigate the ignition and combustion characteristics of three different rank coals at variable oxygen partial pressures in O{sub 2}/N{sub 2} and O{sub 2}/CO{sub 2} environments by Thermo-gravimetric Analyzer (TGA). The experimental results reveal the significant difference of the devolatilization, ignition and combustion properties between three rank coals in O{sub 2}/CO{sub 2} environments. It could provide fundamental understanding on pulverized coal combustion in O{sub 2}/CO{sub 2} environments and elucidate the effect of coal compositions on the ignition and flame stability in pilot-scale oxy-coal combustion.

  5. Thermal stability of hexagonal OsB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Zhilin [Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816 (United States); Blair, Richard G. [Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816 (United States); Department of Physics, University of Central Florida, Orlando, FL 32816 (United States); Orlovskaya, Nina, E-mail: Nina.Orlovskaya@ucf.edu [Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816 (United States); Cullen, David A. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Andrew Payzant, E. [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2014-11-15

    The synthesis of novel hexagonal ReB{sub 2}-type OsB{sub 2} ceramic powder was performed by high energy ball milling of elemental Os and B powders. Two different sources of B powder have been used for this mechanochemical synthesis. One B powder consisted of a mixture of amorphous and crystalline phases and a mixture of {sup 10}B and {sup 11}B isotopes with a fine particle size, while another B powder was a purely crystalline (rhombohedral) material consisting of enriched {sup 11}B isotope with coarse particle size. The same Os powder was used for the synthesis in both cases. It was established that, in the first case, the hexagonal OsB{sub 2} phase was the main product of synthesis with a small quantity of Os{sub 2}B{sub 3} phase present after synthesis as an intermediate product. In the second case, where coarse crystalline {sup 11}B powder was used as a raw material, only Os{sub 2}B{sub 3} boride was synthesized mechanochemically. The thermal stability of hexagonal OsB{sub 2} powder was studied by heating under argon up to 876 °C and cooling in vacuo down to −225 °C. During the heating, the sacrificial reaction 2OsB{sub 2}+3O{sub 2}→2Os+2B{sub 2}O{sub 3} took place due to presence of O{sub 2}/water vapor molecules in the heating chamber, resulting in the oxidation of B atoms and formation of B{sub 2}O{sub 3} and precipitation of Os metal out of the OsB{sub 2} lattice. As a result of such phase changes during heating, the lattice parameters of hexagonal OsB{sub 2} changed significantly. The shrinkage of the a lattice parameter was recorded in 276–426 °C temperature range upon heating, which was attributed to the removal of B atoms from the OsB{sub 2} lattice due to oxidation followed by the precipitation of Os atoms and formation of Os metal. While significant structural changes occurred upon heating due to presence of O{sub 2}, the hexagonal OsB{sub 2} ceramic demonstrated good phase stability upon cooling in vacuo with linear shrinkage of the lattice

  6. Neutron production from (. cap alpha. ,n) reactions and spontaneous fission in ThO/sub 2/, UO/sub 2/, and (U,Pu)O/sub 2/ fuels

    Energy Technology Data Exchange (ETDEWEB)

    Perry, R.T.; Wilson, W.B.

    1981-06-01

    Available alpha-particle stopping cross-section and /sup 17/ /sup 18/O(..cap alpha..,n) cross-section data were adjusted, fitted, and used in calculating the thick-target neutron production function for alpha particles below 10 MeV in oxide fuels. The spent UO/sub 2/ function produced was folded with actinide decay spectra to determine (..cap alpha..,n) neutron production by each of 89 actinides. Spontaneous-fission (SF) neutron production for 40 actinides was calculated as the product of anti ..nu..(SF) and SF branching-fraction values accumulated or estimated from available data. These contributions and total neutron production in spent UO/sub 2/ fuel are tabulated and, when combined with any calculated inventory, describe the spent UO/sub 2/ neutron source. All data are tabulated and methodology is described to permit easy extension to specialized problems.

  7. /sup 15/N/sub 2/ diffusion in soil during biological dinitrogen fixation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, M.P. (Lyon-1 Univ., 69 - Villeurbanne (France). Dept. de Biologie Vegetale); Warembourg, F.R. (Centre National de la Recherche Scientifique, 34 - Montpellier (France). Centre d' Etudes Phytosociologiques et Ecologiques Louis-Emberger)

    1983-01-01

    The kinetic of /sup 15/N/sub 2/ diffusion has been measured in a system similar to that for the estimation of N/sub 2/ fixation in plant microorganism associations cultivated in soil. The /sup 15/N/sub 2/ enrichment of the soil atmosphere reached an homogenous value one hour after injection of /sup 15/N/sub 2/ and is identical to that obtained by calculation, indicating that no adsorption occurs in the soil particles.

  8. Confined release of CO{sub 2} into the ocean

    Energy Technology Data Exchange (ETDEWEB)

    Adams, E.E.; Zhang, X.Y.; Herzog, H.J. [Massachusetts Inst. of Technology, Cambridge, MA (United States)] [and others

    1993-12-31

    To help reduce global warming, it has been proposed to sequester some CO{sub 2} in the deep ocean. However, current pipe technology is limited to about 600-650 m{sup 4}, so deeper transport requires other means. Recently, it was suggested that CO{sub 2} could be released at depths of 200 - 400 m as a concentrated seawater solution. The dense solution would form a negatively buoyant gravity current and sink to greater depth. In the following we expand our previous calculations showing that an unconfined release of CO{sub 2} will not create sufficient concentration or negative buoyancy. However, release of either compressed gaseous or liquid CO{sub 2} into an appropriately designed confinement vessel could produce sufficient concentration to transport the current to deeper water. Furthermore, such a scheme may facilitate formation of CO{sub 2} hydrate particles that are heavier than seawater, causing further sinking. A recently completed Research Needs assessment study which we conducted for DOE concludes that shallow water disposal of CO{sub 2} may be the most promising CO{sub 2} disposal option.

  9. Fabrication, magnetic and microwave absorbing properties of Ba{sub 2}Co{sub 2}Cr{sub 2}Fe{sub 12}O{sub 22} hexagonal ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Bayrakdar, Harun, E-mail: h.bayrakdar@comu.edu.tr

    2016-07-25

    We have investigated the magnetic and microwave absorbing behavior of Ba{sub 2}Co{sub 2}Cr{sub 2}Fe{sub 12}O{sub 22} Nano Particles (NPs)/polyaniline (PANI) and polyacrylonitrile (PAN) nanocomposite materials. Particles showed phase purity and crystallinity in powder X ray diffraction (XRD) analysis. Temperature dependence of magnetic parameters was observed. Microwave absorbing showed very broad and high reflection loss. - Highlights: • Ba{sub 2}Co{sub 2}Cr{sub 2}Fe{sub 12}O{sub 22} NPs were investigated magnetic and absorbing behavior. • VSM measurements of NPs were showed the existence of superparamagnetism with very small coercivity and soft ferrite materials. • Nanocomposites showed higher EM absorption frequency and wider absorption bandwidth.

  10. Rotational multiphoton endoscopy with a 1 microm fiber laser system.

    Science.gov (United States)

    Liu, Gangjun; Xie, Tuqiang; Tomov, Ivan V; Su, Jianping; Yu, Lingfeng; Zhang, Jun; Tromberg, Bruce J; Chen, Zhongping

    2009-08-01

    We present multiphoton microendoscopy with a rotational probe and a 1 microm fiber-based femtosecond laser. The rotational probe is based on a double-clad photonic crystal fiber, a gradient index lens, a microprism, and a rotational microelectronicmechanical system (MEMS) motor. The MEMS motor has a diameter of 2.2 mm and can provide 360 degrees full-view rotation. The fiber laser provides ultrashort pulses with a central wavelength at 1.034 microm and a repetition rate of 50 MHz. Second-harmonic-generation images of rat-tail tendon and fish scale are demonstrated with the rotational probe-based multiphoton system.

  11. Methanol reformer with water vapor and oxygen in catalysts of Cu/CeO{sub 2}-ZrO{sub 2} to generate H{sub 2}; Reformado de metanol con vapor de agua y oxigeno en catalizadores de Cu/CeO{sub 2}-ZrO{sub 2} para generar H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Aguila M, M.M. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2007-07-01

    activity and selectivity. The surface area of the mixed oxides was modified with the cerium addition to the zirconia having as area in ZrO{sub 2} 7m{sup 2}/g and for CeO{sub 2} of 60 m{sup 2}/g and it was modified respectively with a slight decrease of 5 and 56 m{sup 2}/g. The crystalline phases present in the catalysts are the tetragonal and the monoclinic in the catalyst Cu/ZrO{sub 2}; tetragonal in the catalyst rich in zirconia (Cu/ZC10). For the catalysts Cu/CeO{sub 2} and Cu/ZC90 the cerianite phase is identified (characteristic of the cubic structure of the cerium). In the catalyst Cu/ZC50 a mixture of oxides made up of zirconia-cerium is observed (tetragonal and cubic). The morphology shows semi spheric particles for the materials rich in ZrO{sub 2} and planar added in the materials rich in CeO{sub 2} that in turn form attaches of greater dimensions. All the TPR profiles was characterized to present consumption peaks of H{sub 2} associated with the CuO reduction. The addition of CeO{sub 2} to ZrO{sub 2} promotes the reduction from the CuO at low temperatures regarding to the catalyst Cu/ZrO{sub 2}. It is clearly observed that the biggest activity in the transformation of the methanol was in the catalysts rich in cerium in the whole temperature interval studied. As long as for the catalysts rich in zirconia and in the catalyst Cu/ZC50 the increment in the catalytic activity was smaller in function of the temperature. To the maximum reaction temperature (300 C) it was observed the following behavior: Cu/CeO{sub 2} {approx_equal} Cu/ZC90 > Cu/ZC50 > Cu/ZC10 > Cu/ZrO{sub 2}. It is important to mention that the catalysts more active are those that present peaks of copper reduction to smaller 300 C. As for the selectivity toward the H{sub 2}, in the region of high methanol conversion the rich catalysts in cerium presented bigger selectivity regarding the catalysts rich in zirconia. Due to the methanol conversion increases conforms to it increased the reaction temperature

  12. Electrochemical behaviour of TiO{sub 2} reinforced Al 7075 composite

    Energy Technology Data Exchange (ETDEWEB)

    Karunanithi, R., E-mail: karunaponni@gmail.com; Bera, Supriya; Ghosh, K.S., E-mail: ksghosh2001@yahoo.co.uk

    2014-12-15

    Graphical abstract: - Highlights: • Clustering of TiO{sub 2} particle and porosity increased with increasing TiO{sub 2}. • Coarse and numerous very fine η′ and η precipitates in T6 temper composite. • Shifting corrosion potential to noble direction with increasing TiO{sub 2}. • Corrosion is maximum for 30 vol.% TiO{sub 2} composite and least for 7075 alloy. • Pitting damage greater with the increasing TiO{sub 2}. - Abstract: Microstructures of sintered Al 7075 alloy and Al 7075 alloy reinforced with varying TiO{sub 2} composites exhibited uniform distribution of TiO{sub 2} particles, but clustering and porosity have increased with TiO{sub 2} content. TEM micrographs of the Al 7075 alloy and Al 7075 + TiO{sub 2} composite of peak aged T6 (PA) temper showed some coarse and numerous very fine η′ (MgZn{sub 2}) precipitates, and equilibrium η (MgZn{sub 2}) precipitates along the grain boundaries. Potentiodynamic electrochemical polarisation studies on the Al 7075 alloy of different tempers and Al 7075 + TiO{sub 2} composites in 3.5 wt.% NaCl solution showed that the corrosion potentials (E{sub corr}) have shifted towards noble direction with the addition of TiO{sub 2}, and there is an increase of corrosion current density (i{sub corr}) beyond 10 vol.% TiO{sub 2} in the composites. This is attributed to the increase in particle-matrix interface areas enhancing pitting corrosion. Optical micrographs of the corroded surface of 30% TiO{sub 2} composites exhibited maximum pitting damage.

  13. Fabrication of TiO{sub 2}/Ag{sub 2}O heterostructure with enhanced photocatalytic and antibacterial activities under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bingkun, E-mail: liubk2015@zzuli.edu.cn [School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Mu, Lilong; Han, Bing [School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Zhang, Jingtao [School of Food and Bioengineering, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Shi, Hengzhen, E-mail: shihz@zzuli.edu.cn [School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002 (China)

    2017-02-28

    Highlights: • TiO{sub 2}/Ag{sub 2}O composite photocatalyst was synthesized successfully. • The composites show better photocatalytic activity for MB under visible light. • The composites also possess good antibacterial properties. • The mechanism of enhanced photocatalytic activities was investigated. - Abstract: TiO{sub 2}/Ag{sub 2}O heterostructure prepared by a facile in situ precipitation route was used as an effective visible light-driven photocatalyst for degradation of methylene blue (MB) and inactivation of E. coli. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed that Ag{sub 2}O nanoparticles were well distributed on the surface of TiO{sub 2} microspheres. The TiO{sub 2}/Ag{sub 2}O composite with optimal mass ratio of TiO{sub 2} and Ag{sub 2}O displayed extremely good photodegradation ability and antibacterial capability under visible light irradiation, which was mainly ascribed to the synergistic effect between Ag{sub 2}O and TiO{sub 2,} including highly dispersed smaller Ag{sub 2}O particles, increased visible light absorption and efficient separation of photo-induced charge carriers. Meanwhile, the roles of the radical species in the photocatalysis process were investigated. Our results showed that the TiO{sub 2}/Ag{sub 2}O could be used as a dual functional material in water treatment of removing the organic pollutant and killing the bacterium at the same time.

  14. Synthesis of TiO{sub 2} sol in a neutral solution using TiCl{sub 4} as a precursor and H{sub 2}O{sub 2} as an oxidizing agent

    Energy Technology Data Exchange (ETDEWEB)

    Sasirekha, Natarajan; Rajesh, Baskaran [Department of Chemical Engineering, National Central University, Chung-Li 320, Taiwan (China); Chen, Yu-Wen, E-mail: ywchen@cc.ncu.edu.t [Department of Chemical Engineering, National Central University, Chung-Li 320, Taiwan (China)

    2009-11-02

    Nanosize TiO{sub 2} thin film on glass substrate was obtained through dip-coating method using TiO{sub 2} sol. Suspended nanosize TiO{sub 2} sols with anatase structure in aqueous solution were synthesized by sol-gel method using TiCl{sub 4} as a precursor. TiCl{sub 4} was reacted with an aqueous solution of NH{sub 4}OH to form Ti(OH){sub 4}, and H{sub 2}O{sub 2} was then added to form peroxo titanic acid. It was further heated in water and converted to TiO{sub 2}. The effects of the preparation parameters, viz., pH value of the Ti(OH){sub 4} gel, concentration of H{sub 2}O{sub 2}, and heating temperature and time, on the properties of the TiO{sub 2} sol were investigated. The materials were characterized by X-ray diffraction, Fourier transform-infrared spectroscopy, and transmission electron microscopy. The results showed that the primary TiO{sub 2} particles were rhombus with the major axis ca. 10 nm and minor axis ca. 4 nm, and were in anatase structure. The sol was excellent in dispersibility and was stable in neutral and even slight basic conditions for at least 2 years without causing agglomeration. The best preparation condition was optimized with the pH value of Ti(OH){sub 4} gel at 8, H{sub 2}O{sub 2}/TiO{sub 2} mole ratio of 2, and heating at 97 {sup o}C for 8 h. The transparent adherent TiO{sub 2} film on glass substrates exhibits strong hydrophilicity after illuminating with ultraviolet light and it can be used as an efficient photocatalyst.

  15. Electrodeposition of flake-like Cu{sub 2}O on vertically aligned two-dimensional TiO{sub 2} nanosheet array films for enhanced photoelectrochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lei [School of Physics & Material Science, Anhui University, Hefei 230601 (China); Co-operative Innovation Research Center for Weak Signal-Detecting Materials and Devices Integration, Anhui University, Hefei 230601 (China); Institute of Applied Physics AOA, Hefei 230031 (China); Zhang, Miao; Zhu, Kerong [School of Physics & Material Science, Anhui University, Hefei 230601 (China); Lv, Jianguo [School of Electronic & Information Engineering, Hefei Normal University, Hefei 230601 (China); He, Gang [School of Physics & Material Science, Anhui University, Hefei 230601 (China); Sun, Zhaoqi, E-mail: szq@ahu.edu.cn [School of Physics & Material Science, Anhui University, Hefei 230601 (China)

    2017-01-01

    Highlights: • Flake-like Cu{sub 2}O/TNS with exposed {001} facets constructed p-n heterostructure. • The TNS arrays were used as starting substrates for Cu{sub 2}O growth. • The Cu{sub 2}O/TNS prepared at −0.4 V exhibits the best photoelectrochemical property. - Abstract: A novel Cu{sub 2}O/TNS composite structure of single crystal TiO{sub 2} nanosheet (TNS) arrays decorated with flake-like Cu{sub 2}O were synthesized by a facile hydrothermal reaction followed by the electrodeposition process. The effects of deposition potential on the microstructure, morphology, and optical property of the thin films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis spectrophotometer. When the deposition potential is higher than −0.4 V, peaks corresponding to Cu appear, meanwhile, flake-like Cu{sub 2}O become agglomerating, and transform into dense Cu{sub 2}O particles. Additionally, photoelectrochemical experiments indicate that the films deposited at −0.4 V show the lowest resistivity and highest exciton separation efficiency. This enhanced photoelectrochemical properties can be explained by synergistic effect of p-type flake-like Cu{sub 2}O and n-type TiO{sub 2} heterojunctions combined with two-dimensional TiO{sub 2} nanosheet with exposed highly reactive {001} facets.

  16. CO{sub 2} sequestration technologies

    Energy Technology Data Exchange (ETDEWEB)

    Ketzer, Marcelo [Brazilian Carbon Storage Research Center (Brazil)

    2008-07-15

    In this presentation the importance of the capture and sequestration of CO{sub 2} is outlined for the reduction of gas discharges of greenhouse effect; then the principles of CO{sub 2} storage in geologic formations are reviewed; afterwards, the analogs for the CO{sub 2} storage are commented, such as the storage of the acid gas, the natural gas storage and the natural CO{sub 2} deposits. Also it is spoken on the CO{sub 2} storage in coal, in water-bearing saline deposits and in oil fields, and finally the subject of the safety and monitoring of the CO{sub 2} storage is reviewed. [Spanish] En esta presentacion se expone la importancia de la captura y secuestro de CO{sub 2} para la reduccion de emisiones de gases de efecto invernadero; luego se tratan los principios de almacenamiento de CO{sub 2} en formaciones geologicas; despues se comentan los analogos para el almacenamiento de CO{sub 2} como el almacenamiento del gas acido, el almacenamiento de gas natural y los yacimientos naturales de CO{sub 2}. Tambien se habla sobre el almacenamiento de CO{sub 2} en carbon, acuiferos salinos y yacimientos petroliferos y por ultimo se toca el tema de la seguridad y monitoreo del almacenamiento de CO{sub 2}.

  17. Solar reduction of CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Reed J.; Lyman, John L.; King, Joe D.; Guettler, Robert D.

    1998-12-01

    The red shift of the absorption spectrum of CO{sub 2} with increasing temperature, along with CO stabilization are the foundation of a process for direct solar reduction of CO{sub 2} to liquid fuels. The result is a process capable of using renewable solar energy to directly reduce CO{sub 2} from the atmosphere or stationary sources for recycle as a liquid fuel resulting in a net decrease in CO{sub 2} in the atmosphere and decreased demand on fossil fuel. The process includes in sequence: preparation of adequately pure CO{sub 2} feed; preheating CO{sub 2} to near 1,800 K; breaking the CO{sub 2} bonds to produce CO, O{sub 2} and O; quenching the hot product mix by rapid admixture with room temperature CO{sub 2}; removing excess thermal energy to produce electricity, heat new CO{sub 2} and enable subsequent process steps; removing the remaining CO{sub 2} from the gas; removing oxygen from the gas; converting part of the product CO to H{sub 2} by the shift reaction; and, finally, catalytically synthesizing methanol from the synthetic gas.

  18. YPd{sub 2}Al and YPd{sub 2}Zn with LiCu{sub 2}Sn type structure

    Energy Technology Data Exchange (ETDEWEB)

    Gerke, Birgit; Rodewald, Ute C.; Poettgen, Rainer [Institut fuer Anorganische und Analytische Chemie, Universitaet Muenster, Corrensstrasse 30, 48149 Muenster (Germany)

    2016-05-15

    The palladium-rich phases YPd{sub 2}Al and YPd{sub 2}Zn were synthesized from the elements; YPd{sub 2}Al by arc-melting and YPd{sub 2}Zn by induction melting in a sealed niobium ampoule. The structure of YPd{sub 2}Al was refined from single-crystal X-ray diffractometer data: LiCu{sub 2}Sn type, P6{sub 3}/mmc, a = 433.9(2), c = 910.5(2) pm, wR{sub 2} = 0.0497, 150 F{sup 2} values, and 9 variables. The lattice parameters of YPd{sub 2}Zn are a = 437.3(1) and c = 891.4(2) pm. The aluminum atoms in YPd{sub 2}Al show strongly flattened octahedral palladium coordination. These AlPd{sub 6} octahedra are condensed via edges, forming layers around z = 0 and z = 1/2, which are condensed in c direction by weak Pd-Pd bonds. The yttrium atoms fill the cavities between these layers. YPd{sub 2}Al and YPd{sub 2}Zn belong to a larger family of 341 compounds with the Wyckoff sequence 194,fca. The distinctly different crystal chemical branches are briefly discussed. (Copyright copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Measurement of the centrality dependence of the charged particle pseudorapidity distribution in lead-lead collisions at √ s.sub.NN./sub. = 2.76 TeV with the ATLAS detector

    Czech Academy of Sciences Publication Activity Database

    Aad, G.; Abbott, B.; Abdallah, J.; Chudoba, Jiří; Gallus, Petr; Gunther, Jaroslav; Hruška, I.; Juránek, Vojtěch; Kepka, Oldřich; Kupčo, Alexander; Kůs, Vlastimil; Kvasnička, O.; Lipinský, L.; Lokajíček, Miloš; Marčišovský, Michal; Mikeštíková, Marcela; Myška, Miroslav; Němeček, Stanislav; Panušková, M.; Růžička, Pavel; Schovancová, Jaroslava; Šícho, Petr; Staroba, Pavel; Svatoš, Michal; Taševský, Marek; Tic, Tomáš; Valenta, J.; Vrba, Václav

    2012-01-01

    Roč. 710, č. 3 (2012), s. 363-382 ISSN 0370-2693 R&D Projects: GA MŠk LA08032 Institutional research plan: CEZ:AV0Z10100502 Keywords : charged particle multiplicity * charged particle density * charged particle yield * semiconductor detector * pixel * CERN LHC Coll * ATLAS Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.569, year: 2012 http://www.sciencedirect.com/science/article/pii/S0370269312001864

  20. Electron microscopy of Mg/TiO{sub 2} photocatalyst morphology for deep desulfurization of diesel

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Yee Cia, E-mail: gabrielle.ciayin@gmail.com [Department of Chemical Engineering, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia); Kait, Chong Fai, E-mail: chongfaikait@petronas.com.my; Fatimah, Hayyiratul, E-mail: hayyiratulfatimah@yahoo.com; Wilfred, Cecilia, E-mail: cecili@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    A series of Mg/TiO{sub 2} photocatalysts were prepared and characterized using Field Emission Scanning Electron Microscopy (FESEM) and High-Resolution Transmission Electron Microscopy (HRTEM). The average particle sizes of the photocatalysts were ranging from 25.7 to 35.8 nm. Incorporation of Mg on TiO{sub 2} did not lead to any surface lattice distortion to TiO{sub 2}. HRTEM data indicated the presence of MgO and Mg(OH){sub 2} mixture at low Mg loading while at higher Mg loading, the presence of lamellar Mg-oxyhydroxide intermediates and Mg(OH){sub 2}.

  1. Stability of cubic ZrO[sub 2] (10 mol. % Y[sub 2]O[sub 3]) when alloyed with NiO, Al[sub 2]O[sub 3] or TiO[sub 2]: implications to solid electrolytes and cermets

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shueiyuan (Inst. of Materials Science and Engineering, National Sun Yat-Sen Univ., Kaohsiung (Taiwan, Province of China)); Deng Wenhow (Inst. of Materials Science and Engineering, National Sun Yat-Sen Univ., Kaohsiung (Taiwan, Province of China)); Shen Pouyan (Inst. of Materials Science and Engineering, National Sun Yat-Sen Univ., Kaohsiung (Taiwan, Province of China))

    1994-01-01

    This work uses room temperature X-ray diffraction and electron microscopy to investigate the solution of NiO, Al[sub 2]O[sub 3] or TiO[sub 2] in cubic (c-) ZrO[sub 2] (with 10 mol.% Y[sub 2]O[sub 3], designated as yttria fully stabilized zirconia (Y-FSZ)) powders and the consequent destabilization, if any, of Y-FSZ. After sintering at 1600 C for 4 h, the dissolution of the additives (the solubilities are > 15 mol.% for TiO[sub 2], ca. 5-10 mol.% for NiO and rather limited for Al[sub 2]O[sub 3]) caused a smaller cell volume of c-ZrO[sub 2]. Among the additives, only TiO[sub 2] causes the precipitation of tetragonal (t-) ZrO[sub 2] in c-ZrO[sub 2] matrix. The increased solution of TiO[sub 2] in Y-FSZ results in a larger tetragonality of t-ZrO[sub 2], but the t-ZrO[sub 2] precipitates remain as twin-related colony structure with [l brace]101[r brace] habit plane, the same as for the ZrO[sub 2]-Y[sub 2]O[sub 3] system. Due to oversaturation, the added NiO or Al[sub 2]O[sub 3] appears as second phase particles which hindered the grain growth of c-ZrO[sub 2]. The implication of these results to zirconia electrolyte cell and metal/ceramic joints such as thermal barrier coating (TBC) are discussed. (orig.)

  2. CO sub 2 abatement policy

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, L.; Locher, K. (DGM, VROM, Leidschendam (Netherlands). Air Dept.)

    1991-01-01

    'One of the prerequisites for sustainable development - the aim of Dutch environmental policy - is an effective climate policy. That means drastic cuts in CO{sub 2} emissions', according to Leon Janssen, leader of the climate change project at the Ministry of Housing, Physical Planning and Environment. The government recently presented a memorandum on Climate Change to Parliament, setting out the government's position, and confirming the policy already embodied in the 1990 National Environmental Policy Plan Plus. That plan called for carbon dioxide emissions to be stabilised at the 1989/90 level by 1994/5, a reduction of between 3 and 5 percent by the year 2000, and further reductions thereafter. The memorandum on Climate Change also sets targets for stabilising emissions of nitrous oxide and reducing methane and carbon monoxide emissions by 10% and 50% of their 1990 levels respectively. The Netherlands is a staunch supporter of a world convention on climate which may be signed at UNCED in Brazil in June 1992. Comment is made on current effort in the Netherlands aimed at improving the environmental and conserving energy. Campaigns being organized by Dutch environment pressure groups are mentioned.

  3. The trade-off between N{sub 2}, NO and N{sub 2}O under fluidized bed combustor conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wartha, C.; Winter, F.; Hofbauer, H. [Vienna University of Technology, Vienna (Austria). Inst. of Chemical Engineering

    2000-06-01

    To obtain a better understanding of the formation and destruction paths of NO and N{sub 2}O, comprehensive studies have been performed in a laboratory-scale fluidized bed reactor optimized to obtain formation rates. The influence of the temperature and radicals on the NO and N{sub 2}O formation from HCN and NH{sub 3} and destruction reactions were studied. The results show that N{sub 2}O is formed only from HCN. Oxidation of NH{sub 3} forms NO and N{sub 2}, HCN forms NO, N{sub 2}O and N{sub 2}. Typically, 30 to 70% of NH{sub 3} are converted to N{sub 2}, depending on bed temperature. In the case of HCN, only 5 to 25% are converted to N{sub 2}. At temperatures below 800{degree}C, NO reacts with CH{sub 4} oxidation products to NO{sub 2}. Tests with HCN show that HCN conversion starts already at 700{degree}C in the fluidized bed, N{sub 2}O is formed in significant amounts only in the presence of CH{sub 4}. The results of the NO and N{sub 2} destruction tests show that the thermal mechanism is of minor importance. At 900{degree}C, N{sub 2} destruction with H radicals can be seen. N{sub 2} formation shows a maximum at 850{degree}C. The gas reaction studies were used to understand the NH{sub 3}, HCN, NO and N{sub 2}O single-particle formation characteristics of coke, bituminous coal, peat, and spruce wood under fluidized bed combustor conditions.

  4. Copper(I) Complexes of N-thiophosphorylated Bis-thiourea [CH^sub 2^NHC(S)NHP(S)(OiPr)^sub 2^]^sub 2^ and Phosphines (PPh^sub 3^, Ph^sub 2^P(CH^sub 2^)^sub 1-3^PPh^sub 2^, Ph^sub 2^P(C^sub 5^H^sub 4^FeC^sub 5^H^sub 4^)PPh^sub 2^): Versatile Structures and Luminescence

    National Research Council Canada - National Science Library

    Damir A Safin; Maria G Babashkina; Axel Klein

    2010-01-01

    ...^{Ph^sub 2^P(CH^sub 2^)^sub 3^PPh^sub 2^}^sub 2^L] (4) or [Cu^sub 2^{Ph^sub 2^P(C^sub 5^H^sub 4^FeC^sub 5^H^sub 4^)PPh^sub 2^}^sub 2^L] (5) complexes. The structures of these compounds were investigated by IR...

  5. Simultaneous treatment of NO and SO{sub 2} with aqueous NaClO{sub 2} solution in a wet scrubber combined with a plasma electrostatic precipitator

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyun-Woo [Department of Chemistry and Chemical Engineering and Regional Innovation Center for Environmental Technology of Thermal Plasma (RIC-ETTP), INHA University, 100 Inha-ro, Nam-gu, Incheon 402-751 (Korea, Republic of); Choi, Sooseok, E-mail: sooseok@jejunu.ac.kr [Department of Nuclear and Energy Engineering, Jeju National University, 102 Jejudaehak-ro, Jeju-si, Jeju Special Self-Governing Province, 690-756 (Korea, Republic of); Park, Dong-Wha, E-mail: dwpark@inha.ac.kr [Department of Chemistry and Chemical Engineering and Regional Innovation Center for Environmental Technology of Thermal Plasma (RIC-ETTP), INHA University, 100 Inha-ro, Nam-gu, Incheon 402-751 (Korea, Republic of)

    2015-03-21

    Highlights: • This study was conducted to investigate simultaneous removal of NO and SO{sub 2}. • Proposed process consists of wet chemical reactor and non-thermal plasma reactor. • In the wet chemical reactor, NO and SO{sub 2} were absorbed and oxidized by NaClO{sub 2}. • In the non-thermal plasma reactor, aerosol particles were collected on anode surface. • NO and SO{sub 2} were removed more efficiently by proposed process than other methods. - Abstract: NO and SO{sub 2} gases that are generally produced in thermal power plants and incinerators were simultaneously removed by using a wet scrubber combined with a plasma electrostatic precipitator. The wet scrubber was used for the absorption and oxidation of NO and SO{sub 2}, and non-thermal plasma was employed for the electrostatic precipitation of aerosol particles. NO and SO{sub 2} gases were absorbed and oxidized by aerosol particles of NaClO{sub 2} solution in the wet scrubber. NO and SO{sub 2} reacted with the generated NaClO{sub 2} aerosol particles, NO{sub 2} gas, and aqueous ions such as NO{sub 2}{sup −}, NO{sub 3}{sup −}, HSO{sub 3}{sup −}, and SO{sub 4}{sup 2−}. The aerosol particles were negatively charged and collected on the surface of grounded anode in the plasma electrostatic precipitator. The NO and SO{sub 2} removal efficiencies of the proposed system were 94.4% and 100% for gas concentrations of 500 mg/m{sup 3} and a total gas flow rate of 60 Nm{sup 3}/h, when the molar flow rate of NaClO{sub 2} and the gas–liquid contact time were 50 mmol/min and 1.25 s, respectively. The total amount and number of aerosol particles in the exhaust gas were reduced to 7.553 μg/m{sup 3} and 210 /cm{sup 3} at the maximum plasma input power of 68.8 W, which are similar to the values for clean air.

  6. Structural, dielectric and magnetic properties of SnO{sub 2}-CuFe{sub 2}O{sub 4} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Kashif [Department of Physics, International Islamic University, Islamabad (Pakistan); Iqbal, Javed, E-mail: javed.saggu@qau.edu.pk [Laboratory of Nanoscience and Technology (LNT), Department of Physics, Qaid-i-Azam University, Islamabad (Pakistan); Jan, Tariq [Department of Physics, University of Lahore, Sargodha Campus, Sargodha (Pakistan); Wan, Dongyun [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Ahmad, Naeem [Department of Physics, International Islamic University, Islamabad (Pakistan); Ahamd, Ishaq [Experimental Physics Labs, National Center for Physics, Islamabad (Pakistan); Ilyas, Syed Zafar [Department of Physics, Allama Iqbal Open University, Islamabad (Pakistan)

    2017-04-15

    The nanocomposites of (SnO{sub 2}){sub x}(CuFe{sub 2}O{sub 4}){sub (1−x)} (where x=0–100 wt%) have been successfully synthesized via two steps chemical method. XRD pattern has revealed the formation of inverse spinal phases with tetragonal crystal structure without any impurity phases for CuFe{sub 2}O{sub 4} sample. The thermodynamic solubility limit of SnO{sub 2} in CuFe{sub 2}O{sub 4} matrix has been found to be 30 wt% and above this percentage crystal phases related to SnO{sub 2} started to appear. The average particle size and shape of CuFe{sub 2}O{sub 4} nanoparticles have been strongly influenced by addition of SnO{sub 2} as depicted by TEM results. FTIR results have confirmed the existence of cation vibration bands at tetrahedral and octahedral sites along with Sn-O vibration band at higher concentrations, which also validates the formation of nanocomposites. Furthermore, the dielectric constant, tangent loss and conductivity of CuFe{sub 2}O{sub 4} nanoparticles have been found to increase up to 30 wt% addition of SnO{sub 2} and then decreases with further increase which is attributed to variations in resistivity and space charge carriers. Magnetic measurements have shown that saturation magnetization decreases from 35.68 emu/gm to 10.26 emu/gm with the addition of SnO{sub 2} content. - Highlights: • SnO{sub 2}-CuFe{sub 2}O{sub 4} nanocomposites with varying SnO{sub 2} concentrations were synthesized. • The thermodynamic solubility limit for SnO{sub 2} into CuFe{sub 2}O{sub 4} matrix by employing current method was found to be ≤30 wt%. • At higher concentrations, structural phases related to SnO{sub 2} started to appear. • FTIR results corroborated well with the XRD results. • It has been observed that the addition of SnO{sub 2} significantly influence the morphology, dielectric and magnetic properties of CuFe{sub 2}O{sub 4} nanoparticles.

  7. CO{sub 2} sequestration; La sequestration du CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Favre, E. [Nancy-1 Univ., Lab. des Sciences du Genie Chimique - ENSIC, 54 (France); Jammes, L. [Schlumberger Carbon Services, 75 - Paris (France); Guyot, F. [Paris-Diderot Univ., Institut de Mineralogie et de Physique des Milieux Condenses (IMPMC), Institut de Physique du Globe de Paris (IPGP), 75 - Paris (France); Prinzhofer, A. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France); Institut de Physique du Globe de Paris, 75 (France); Le Thiez, P. [GEOGREEN, 92 - Rueil-Malmaison (France)

    2009-07-01

    This document presents the summary of a conference-debate held at the Academie des Sciences (Paris, France) on the topic of CO{sub 2} sequestration. Five papers are reviewed: problems and solutions for the CO{sub 2} sequestration; observation and surveillance of reservoirs; genesis of carbonates and geological storage of CO{sub 2}; CO{sub 2} sequestration in volcanic and ultra-basic rocks; CO{sub 2} sequestration, transport and geological storage: scientific and economical perspectives

  8. Photocatalytic performance of nano-photocatalyst from TiO{sub 2} and Fe{sub 2}O{sub 3} by mechanochemical synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ghorai, Tanmay K., E-mail: tanmay_ghorai@yahoo.co.in [Department of Chemistry, West Bengal State University, Barasat, North 24 Pgs, Kolkata 700126 (India); Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Chakraborty, Mukut [Department of Chemistry, West Bengal State University, Barasat, North 24 Pgs, Kolkata 700126 (India); Pramanik, Panchanan [Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2011-08-11

    Graphical abstract: Nano-particles of homogeneous solution between TiO{sub 2} and Fe{sub 2}O{sub 3} (up to 5 mol%) have been prepared by mechanochemical milling. The results show that the alloy of TiO{sub 2} with 5 mol% of Fe{sub 2}O{sub 3} (YFT1) exhibit photocatalytic activity 3-5 times higher than that of P25 TiO{sub 2} for oxidation of various dyes (RB, MO, TB and BG) under visible light irradiation. The average particle size and crystallite size of YFT1 were found to be 30 {+-} 5 nm and 12 nm measured from TEM and XRD. Optical adsorption edge is found to be 2.26 eV. Tentative schematic diagram of reaction mechanism of YFT/RFT photocatalysts under visible light irradiation. Highlights: > Synthesis of nano-sized homogeneous solid solution between Fe{sub 2}O{sub 3} and TiO{sub 2} with high photocatalytic activity for oxidative degradation of different dyes was successfully obtained through mechanochemical synthesis. XRD data shows the formation of solid solution having anatase structure with no free Fe{sub 2}O{sub 3} up to 5 mol% of Fe{sub 2}O{sub 3}. Fe{sub 2}O{sub 3}/TiO{sub 2} catalyst have crystallite size about 12-13 nm measured from XRD and particle size about 30 {+-} 5 nm measured from TEM. FT-IR of all Fe{sub 2}O{sub 3}/TiO{sub 2} prepared catalysts is similar to pure TiO{sub 2}. The maximum solubility of Fe{sub 2}O{sub 3} in TiO{sub 2} is 5 mol% of Fe{sub 2}O{sub 3} irrespective of source and this composition has highest photocatalytic activity that is 3-5 times higher than P25 TiO{sub 2} for the oxidation of different dyes. We also observed that the rate of degradation of Rhodamine B is faster among all the four dyes under prepared catalyst and visible light. - Abstract: Nano-particles of homogeneous solid solution between TiO{sub 2} and Fe{sub 2}O{sub 3} (up to 10 mol%) have been prepared by mechanochemical milling of TiO{sub 2} and yellow Fe{sub 2}O{sub 3}/red Fe{sub 2}O{sub 3}/precipitated Fe (OH){sub 3} using a planetary ball mill. Such novel solid

  9. Influence of electrode microstructure on the reactivity of Cu{sub 2}Sb with lithium

    Energy Technology Data Exchange (ETDEWEB)

    Morcrette, M.; Larcher, D.; Tarascon, J.M. [Laboratoire de Reactivite et Chimie des Solides, Universite de Picardie Jules Verne, CNRS-UMR 6007, 33 rue Saint Leu, 80039 Amiens Cedex (France); Edstroem, K. [Department of Materials Chemistry, Aangstroem Laboratory, Uppsala University, SE-751 21 Uppsala (Sweden); Vaughey, J.T.; Thackeray, M.M. [Electrochemical Technology Program, Chemical Technology Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2007-05-05

    The reactivity of lithium with Cu{sub 2}Sb was recently described to be governed by displacement reactions of Cu similar to those occurring in Cu{sub 2.33}V{sub 4}O{sub 11}. In order to complement the earlier work of Fransson et al., we have revisited the electrochemical reactivity of Cu{sub 2}Sb with Li. Through a different arsenal of characterization techniques, we have emphasized the role of the particle size, electrode preparation and temperature on the reversibility of the electrochemical reaction. We have demonstrated that the structural reversibility of the Cu{sub 2}Sb electrode can be obtained in two special cases: (1) when the particle size of Cu{sub 2}Sb is small and when the powders are ball milled with carbon and (2) when Li{sub 2}CuSb is used as the starting material and some Sb is lost from the electrode during charge. (author)

  10. Thermal conductivities of irradiated UO{sub 2} and (U, Gd)O{sub 2} pellets

    Energy Technology Data Exchange (ETDEWEB)

    Amaya, Masaki E-mail: amaya@nfd.co.jp; Hirai, Mutsumi; Sakurai, Hiroshi; Ito, Kenichi; Sasaki, Masana; Nomata, Terumitsu; Kamimura, Katsuichiro; Iwasaki, Ryo

    2002-01-01

    Thermal diffusivities of UO{sub 2} and (U, Gd)O{sub 2} pellets irradiated in a commercial reactor (maximum burnups: 60 GWd/t for UO{sub 2} and 50 GWd/t for (U, Gd)O{sub 2}) were measured up to about 2000 K by using a laser flash method. The thermal diffusivities of irradiated UO{sub 2} and (U, Gd)O{sub 2} pellets showed hysteresis phenomena: the thermal diffusivities of irradiated pellets began to recover above 750 K and almost completely recovered after annealing above 1400 K. The thermal diffusivities after recovery were close to those of simulated soluble fission products (FPs)-doped UO{sub 2} and (U, Gd)O{sub 2} pellets, which corresponded with the recovery behaviors of irradiation defects for UO{sub 2} and (U, Gd)O{sub 2} pellets. The thermal conductivities for irradiated UO{sub 2} and (U, Gd)O{sub 2} pellets were evaluated from measured thermal diffusivities, specific heat capacities of unirradiated UO{sub 2} pellets and measured sample densities. The difference in relative thermal conductivities between irradiated UO{sub 2} and (U, Gd)O{sub 2} pellets tended to become insignificant with increasing burnups of samples.

  11. Ocean CO{sub 2} disposal

    Energy Technology Data Exchange (ETDEWEB)

    Shindo, Yuji; Hakuta, Toshikatsu [National Inst. of Materials and Chemical Research, AIST, MITI, Higashi, Tsukuba, Ibaraki (Japan)

    1993-12-31

    Most countries in the world will continue to depend on fossil fuels for their main energy at least for half a country, even in the confrontation with the threat of global warming. This indicates that the development of CO{sub 2} removal technologies such as recovering CO{sub 2} from flue gases and sequestering it of in the deep oceans or subterranean sites is necessary, at least until non-fossil fuel dependent society is developed. Ocean CO{sub 2} disposal is one of the promising options for the sequestration of CO{sub 2} recovered from flue gases. Oceans have sufficient capacity to absorb all the CO{sub 2} emitted in the world. It is very significant to research and develop the technologies for ocean CO{sub 2} disposal.

  12. CO{sub 2} storage technology pathways

    Energy Technology Data Exchange (ETDEWEB)

    Gunter, B. [Alberta Research Council, Edmonton, AB (Canada)

    2005-07-01

    The feasibility of carbon dioxide (CO{sub 2}) storage was discussed with particular reference to how to accelerate commercial development of CO{sub 2} capture and geological storage; the relative positioning of Canadian CO{sub 2} storage research and development; technology horizons for CO{sub 2} storage; policy and performance areas; as well as value added and non-value added storage. It also discussed various needs for CO{sub 2} storage such as the capacity of sedimentary basins; the establishment of environmental integrity; assessing risks and opportunities systematically; tagging onto commercial projects; testing new technology; establishing infrastructure and process to address barriers to development; informing policy; sharing knowledge and learning from others; and coordination of all activities. Several CO{sub 2} storage pilot projects were highlighted. tabs., figs.

  13. Fabrication of Li{sub 2}O-B{sub 2}O{sub 3}-P{sub 2}O{sub 5} solid electrolyte by flame-assisted ultrasonic spray hydrolysis for thin film battery

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Ki-Hyun [Division of Material Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); You, Hyun-Jin [Division of Material Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Youn, Yong-Seb [Division of Material Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Ji-Suk [Division of Material Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Shin, Dong-Wook [Division of Material Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)]. E-mail: dwshin@hanyang.ac.kr

    2006-12-01

    Li{sub 2}O-B{sub 2}O{sub 3}-P{sub 2}O{sub 5} glass soot was fabricated from aqueous precursor solution of a CH{sub 3}CO{sub 2}Li.2H{sub 2}O and BCl{sub 3}, POCl{sub 3} by the flame-assisted ultrasonic spray hydrolysis. The aqueous precursor solution of the lithium acetates was first atomized with an ultrasonic vibrator (1.7 MHz). B{sub 2}O{sub 3} and P{sub 2}O{sub 5} were formed from BCl{sub 3} and POCl{sub 3} by oxy-hydrogen flame. Their properties were investigated by SEM, XRD, TGA-DSC and impedance analyzer. The formed particles in glass soot had spherical shape and the size of approximately 50-100 nm. XRD analysis revealed that the amorphous phase and crystalline phases were mixed in glass soot and the crystalline phases were B(OH){sub 3} and B{sub 2}O{sub 3}. The crystalline B(OH){sub 3} and B{sub 2}O{sub 3} found in glass soot completely disappeared by heat treatment. Conductivity was measured by complex impedance method using impedance analyzer and the conductivity was 10{sup -8} S/cm.

  14. Composite hydroxyapatite/TiO{sub 2} materials for photocatalytic oxidation of NO{sub x}

    Energy Technology Data Exchange (ETDEWEB)

    Giannakopoulou, T., E-mail: tgia@ims.demokritos.gr [NCSR Demokritos, Institute of Materials Science, 153 10 Attikis (Greece); Todorova, N. [NCSR Demokritos, Institute of Materials Science, 153 10 Attikis (Greece); Romanos, G. [NCSR Demokritos, Institute of Physical Chemistry, 153 10 Attikis (Greece); Vaimakis, T. [University of Ioannina, Department of Chemistry, 451 10 Ioannina (Greece); Dillert, R.; Bahnemann, D. [Institut fur Technische Chemie, Leibniz Universitaet Hannover, Callinstrasse 3, D-30167 Hannover (Germany); Trapalis, C., E-mail: trapalis@ims.demokritos.gr [NCSR Demokritos, Institute of Materials Science, 153 10 Attikis (Greece)

    2012-08-01

    Highlights: Black-Right-Pointing-Pointer Higher photocatalytic activity of hydroxyapatite/TiO{sub 2} composites than pure TiO{sub 2}. Black-Right-Pointing-Pointer Increase of the HA/TiO{sub 2} ratio leads to increase of both NO oxidation and NO{sub x} removal. Black-Right-Pointing-Pointer Hydroxyapatite diminishes TiO{sub 2} particles aggregation leading to higher dispersion. - Abstract: Hydroxyapatite/TiO{sub 2} composite photocatalysts were obtained from sol-gel prepared TiO{sub 2} and commercial hydroxyapatite (HA) powders. Composites with different HA/TiO{sub 2} ratio were studied to assess the influence of HA on the morphology and the photocatalytic behavior of the materials. Morphological SEM analysis revealed that the presence of HA diminishes the aggregation of TiO{sub 2} particles and leads to their higher dispersion in the composites that was confirmed by the N{sub 2} adsorption-desorption isotherms and Barret-Joyner-Halenda analysis. The photocatalytic activity of the prepared catalysts was examined by monitoring photocatalytic oxidation of NO{sub x} model gases over catalysts under UV illumination. The NO{sub x} oxidation over the composite catalysts was improved in comparison with pure TiO{sub 2} powder. Moreover, the decrease of the TiO{sub 2} content, which is the photocatalytically active component in the composites, resulted in enhanced NO{sub x} removal. Maximum activity was recorded for composites with HA/TiO{sub 2} ratios 1 and 2 that was related to improved TiO{sub 2} dispersion and NO{sub 2} trapping by the composite materials.

  15. Mechanism of CO <sub>2 Hydrogenation on Pd/Al <sub>2 O 3 Catalysts: Kinetics and Transient DRIFTS-MS Studies

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiang; Shi, Hui; Kwak, Ja Hun; Szanyi, János

    2015-09-17

    The hydrogenation of CO<sub>2 was investigated over a wide range of reaction conditions, using two Pd/γ-Al<sub>2O3 catalysts with different Pd loadings (5% and 0.5%) and dispersions (~11% and ~100%, respectively). Turnover rates for CO and CH4 formation were both higher over 5% Pd/Al<sub>2O3 with a larger average Pd particle size than those over 0.5% Pd/Al<sub>2O3 with a smaller average particle size. The selectivity to methane (22-40%) on 5% Pd/Al<sub>2O3 was higher by a factor of 2-3 than that on 0.5% Pd/Al<sub>2O3. The drastically different rate expressions and apparent energies of activation for CO and CH4 formation lead us to conclude that reverse water gas shift and CO<sub>2 methanation do not share the same rate-limiting step on Pd, and that the two pathways are probably catalyzed at different surface sites. Measured reaction orders in CO<sub>2 and H<sub>2 pressures were similar over the two catalysts, suggesting that the reaction mechanism for each pathway does not change with particle size. In accordance, the DRIFTS results reveal that the prevalent surface species and their evolution patterns are comparable on the two catalysts during transient and steady-state experiments, switching feed gases among CO<sub>2, H<sub>2 and CO<sub>2+H<sub>2. The DRIFTS and MS results also demonstrate that no direct dissociation of CO<sub>2 takes place over the two catalysts, and that CO<sub>2 has to first react with surface hydroxyls on the oxide support. The thus-formed bicarbonates react with dissociatively adsorbed hydrogen on Pd particles to produce adsorbed formate species (bifunctional catalyst: CO<sub>2 activation on the oxide support, and H<sub>2 dissociation on the metal particles). Formates near the Pd particles (most likely at the metal/oxide interface) can react rapidly with adsorbed H

  16. Atmospheric SO{sub 2}. Global measurements using aircraft-based CIMS

    Energy Technology Data Exchange (ETDEWEB)

    Fiedler, V.

    2008-06-27

    Aircraft based measurements of tropospheric sulfur dioxide, SO{sub 2}, have been carried out during four campaigns in South America (TROCCINOX), Australia (SCOUT-O3), Europe (INTEX/MEGAPLUME) and Africa (AMMA). SO{sub 2} has been measured by chemical ionization mass spectrometry (CIMS), permanently online calibrated with isotopically labelled SO{sub 2}. The measurement method is described thoroughly in this work and the measured data are presented. Moreover, the data of the different regions are compared in general and typical air mass situations with SO{sub 2} enhancement are shown. A detailed analysis of four SO{sub 2} pollution plume cases emphasizes the main features: long-range transport, SO{sub 2} from metal smelters/volcanoes or from biomass burning. The SO{sub 2} measurements are analyzed in the light of simultaneously measured trace gas, particle and meteorological data. Air mass trajectory models (FLEXPART or HYSPLIT) are employed for a determination of the pollution origin. Further going evaluations with the aerosol model AEROFOR complete the analyses and point out, that the measured SO{sub 2} mole fractions are sufficient to explain new particle formation and growth. Finally, a first comparison of the measured SO{sub 2} to results from a global circulation model (ECHAM) with implemented sulfur chemistry showed a significant underestimation of the measured SO{sub 2} mole fraction by the model in the free troposphere. (orig.)

  17. Gold-tin ordering in SrAu{sub 2}Sn{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Schwickert, Christian; Gerke, Birgit; Poettgen, Rainer [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie

    2014-07-15

    Samples of the solid solutions SrAu{sub x}Sn{sub 4-x} (1.7 ≤ x ≤ 2.2) were obtained by high-frequency melting of the elements in sealed niobium ampoules. Powder and single-crystal X-ray data confirmed the CaBe{sub 2}Ge{sub 2}-type structure, space group P4/nmm. The structures of SrAu{sub 1.76}Sn{sub 2.24}, SrAu{sub 2}Sn{sub 2}, SrAu{sub 2.16}Sn{sub 1.84} (crystal A), SrAu{sub 2.16}Sn{sub 1.84} (crystal B), and SrAu{sub 2.22}Sn{sub 1.78} were refined from single-crystal diffractometer data. Only the SrAu{sub 2}Sn{sub 2} crystal shows complete Au-Sn ordering while all other crystals show substantial mixed occupancies on the four crystallographically independent sites of the polyanionic networks in which the strontium atoms fill cages of coordination number 16. Temperature-dependent susceptibility measurements have revealed diamagnetism for SrAu{sub 2}Sn{sub 2}. {sup 119}Sn Moessbauer spectroscopic data of a bulk SrAu{sub 2}Sn{sub 2} sample have resolved the tetrahedral and square-pyramidal tin sites but point to substantial Au-Sn disorder.

  18. Elevated temperature cycling stability and electrochemical impedance of LiMn{sub 2}O{sub 4} cathodes with nanoporous ZrO{sub 2} and TiO{sub 2} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Walz, Kenneth A.; Genthe, Jamie; Stoiber, Lucas C.; Zeltner, Walter A.; Anderson, Marc A. [Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N Park Street, Madison, WI 53706 (United States); Johnson, Christopher S.; Thackeray, Michael M. [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9500 Cass Ave., Argonne, IL 60439 (United States)

    2010-08-01

    In this study, nanoporous zirconia (ZrO{sub 2}) and titania (TiO{sub 2}) coatings are shown to stabilize the cycling performance of lithium-ion batteries with LiMn{sub 2}O{sub 4} spinel cathodes. The effect of firing temperature on the coating pore size is discussed and the resulting performance of the coated cathodes is evaluated. Stabilization mechanisms, such as neutralization of acidic electrolytes by ZrO{sub 2} and TiO{sub 2} coatings, are examined. It is proposed that the establishment of a complex nanoporous network for lithium-ion transport results in a more uniform current distribution at the particle surface, thereby suppressing capacity fade that may be associated with surface instabilities of the spinel electrode. (author)

  19. Influence of Al{sub 2}O{sub 3} addition on microstructure and mechanical properties of 3YSZ-Al{sub 2}O{sub 3} composites

    Energy Technology Data Exchange (ETDEWEB)

    Abden, Md. Jaynul [International Islamic Univ., Chittagong (Bangladesh). Dept. of Electrical and Electronic Engineering; Afroze, Jannatul Dil [Noakhali Science and Technology Univ. (Bangladesh). Faculty of Science and Engineering; Gafur, Md. Abdul [Bangladesh Council of Scientific and Industrial Research, Dhaka (Bangladesh). Pilot Plant and Process Development Centre; Chowdhury, Faruque-Uz-Zaman [Chittagong University of Engineering and Technology (Bangladesh). Dept. of Physics

    2015-07-01

    The effect of the amount of Al{sub 2}O{sub 3} content on microstructure, tetragonal phase stability and mechanical properties of 3YSZ-Al{sub 2}O{sub 3} composites are investigated in this study. The ceramic composites are obtained by means of uniaxial compacting at 210 MPa and green compacts are sintered at 1550 C for 3 h in air. The monoclinic zirconia (m-ZrO{sub 2}) phase has completely been transformed into tetragonal zirconia (t-ZrO{sub 2}) phase with corresponding higher Al{sub 2}O{sub 3} content. The t-ZrO{sub 2} grains induce transgranular fracture mode that has contribution in improvement of fracture toughness. The maximum flexural strength of 340 MPa, Vickers hardness value of 14.31 GPa and fracture toughness of 5.1 MPa x m{sup 1/2} in the composition containing 40 wt.-% Al{sub 2}O{sub 3} is attributed to the microstructure with t-ZrO{sub 2} grains as inter- and intragranular particles in the Al{sub 2}O{sub 3} grains, which makes it suitable for dental applications.

  20. Photocatalytic activity of Al{sub 2}O{sub 3}-doped TiO{sub 2} thin films activated with visible light on the bacteria Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Barajas-Ledesma, E., E-mail: edgar_acuario112@hotmail.com [Instituto de Investigaciones Metalurgicas, edificio ' U' , Ciudad Universitaria, UMSNH, Morelia, Michoacan, Mexico, C.P. 58000 (Mexico); Garcia-Benjume, M.L. [Instituto de Investigaciones Metalurgicas, edificio ' U' , Ciudad Universitaria, UMSNH, Morelia, Michoacan, Mexico, C.P. 58000 (Mexico); Espitia-Cabrera, I. [Facultad de Ingenieria Quimica, edificio ' M' , Ciudad Universitaria, UMSNH, Morelia, Michoacan, Mexico, C.P. 58000 (Mexico); Bravo-Patino, A. [Centro Multidisciplinario de Estudios en Biotecnologia, Km 9.5 Carretera Morelia-Zinapecuaro, Posta Veterinaria, Morelia, Michoacan, Mexico, C.P. 58262 (Mexico); Espinoza-Beltran, F.J. [CINVESTAV-Queretaro Libramiento Norponiente 2000, Fracc. Real de Juriquilla, Santiago de Queretaro, Queretaro, Mexico, C.P. 76230 (Mexico); Mostaghimi, J. [Faculty of Applied Science and Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario, M5S 3G8 (Canada); Contreras-Garcia, M.E. [Instituto de Investigaciones Metalurgicas, edificio ' U' , Ciudad Universitaria, UMSNH, Morelia, Michoacan, Mexico, C.P. 58000 (Mexico)

    2010-10-25

    Al{sub 2}O{sub 3}-doped TiO{sub 2} thin films were prepared by combining electrophoretic deposition (EPD) with sputtering. A Corning* glass was used as a substrate, in which a titanium film was deposited by sputtering. Then, a precursor sol was prepared with Ti(n-OBu){sub 4} and Al(s-OBu){sub 3} and used as the medium for EPD. Next, the thin films were sintered and, finally, characterised by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). Several cultures of Escherichia coli, strain XL1-Blue, were prepared. Nine experiments were carried out. In three of them, an inoculum (a low amount of a product that contains bacteria) was prepared without a film; in the other six Al{sub 2}O{sub 3}-doped TiO{sub 2} film-coated glass substrates were irradiated with visible light before they were introduced in the inoculum. The SEM and EDS results showed that TiO{sub 2}-Al{sub 2}O{sub 3} films were obtained, covering all the glass substrate and with uniform size of particles forming them, and that the aluminium was distributed uniformly on the film. XRD results showed that rutile phase was obtained. By TEM, the structure of TiO{sub 2} was demonstrated. Al{sub 2}O{sub 3}-doped TiO{sub 2} thin films were successful at eliminating E. coli.

  1. Sol-gel synthesis of TiO{sub 2}-SiO{sub 2} photocatalyst for {beta}-naphthol photodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Qourzal, S., E-mail: samir_qourzal@yahoo.fr [Equipe de Materiaux Photocatalyse et Environnement, Departement de Chimie, Faculte des Sciences, Universite Ibn Zohr, B. P. 8106 Cite Dakhla, Agadir (Morocco); Barka, N.; Tamimi, M.; Assabbane, A. [Equipe de Materiaux Photocatalyse et Environnement, Departement de Chimie, Faculte des Sciences, Universite Ibn Zohr, B. P. 8106 Cite Dakhla, Agadir (Morocco); Nounah, A. [Ecole Superieure de Technologie, Avenue Prince Heritier Sidi Mohamed, B. P. 227, Sale-Medina (Morocco); Ihlal, A. [Laboratoire de Physique des Semi-conducteurs et Energie Solaire, Departement de Physique, Faculte, des Sciences, Universite Ibn Zohr, B. P. 8106 Cite Dakhla, Agadir (Morocco); Ait-Ichou, Y. [Equipe de Materiaux Photocatalyse et Environnement, Departement de Chimie, Faculte des Sciences, Universite Ibn Zohr, B. P. 8106 Cite Dakhla, Agadir (Morocco)

    2009-06-01

    Silica gel supported titanium dioxide particles (TiO{sub 2}-SiO{sub 2}) prepared by sol-gel method was as photocatalyst in the degradation of {beta}-naphthol in water under UV-illumination. The prepared sample has been characterized by powder X-ray diffraction (XRD), infrared spectroscopy (IR) and scanning electron microscopy (SEM). The supported catalyst had large surface area and good sedimentation ability. The photodegradation rate of {beta}-naphthol under UV-irradiation depended strongly on adsorption capacity of the catalyst, and the photoactivity of the supported catalyst was much higher than that of the pure titanium dioxides. The experiments were measured by high performance liquid chromatography (HPLC). The photodegradation rate of {beta}-naphthol using 60% TiO{sub 2}-SiO{sub 2} particles was faster than that using TiO{sub 2} 'Degussa P-25', TiO{sub 2} 'PC-50' and TiO{sub 2} 'Aldrich' as photocatalyst by 2.7, 4 and 7.8 times, respectively. The kinetics of photocatalytic {beta}-naphthol degradation was found to follow a pseudo-first-order rate law. The effect of the TiO{sub 2} loading on the photoactivity of TiO{sub 2}-SiO{sub 2} particles was also discussed. With good photocatalytic activity under UV-irradiation and the ability to be readily separated from the reaction system, this novel kind of catalyst exhibited the potential effective in the treatment of organic pollutants in aqueous systems.

  2. Growth kinetics of sintered NiO/ZrO[sub 2](5mol. %Y[sub 2]O[sub 3]) composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shueiyuan; Shen Pouyan; Gan Dershin (Inst. of Materials Science and Engineering, National Sun Yat-Sen Univ., Kaohsiung (Taiwan))

    1992-11-01

    This work uses X-ray diffraction and scanning electron microscopy to investigate the solution of NiO and ZrO[sub 2] (with 5 mol% Y[sub 2]O[sub 3], mainly in a metastable t' phase as plasma sprayed powders) and the resultant growth kinetics of the NiO/ZrO[sub 2] composite at 1600degC. The t'-ZrO[sub 2] transforms into cubic (c-)ZrO[sub 2] within 1 h upon firing, and room temperature X-ray lattice parameter results indicate that the solubility of NiO in c-ZrO[sub 2] is about 3 mol%. Within the solubility limit, both sintering and growth of c-ZrO[sub 2] grains were enhanced by NiO addition. A further increase in the NiO content results in the formation of NiO particles which hinder the grain growth of c-ZrO[sub 2]. For specimens with 10 mol% NiO the c-ZrO[sub 2] grains were found to follow the t[sup 1/3] growth kinetics, i.e. bulk diffusion controlled, while the intergranular and intragranular NiO particles coarsen according to t[sup 1/4] and t[sup 1/5] laws respectively. The interfacial energy of NiO/c-ZrO[sub 2] is about 0.48[+-]0.1 J m[sup 2], inferred from the geometry of the NiO particles at the grain boundary. (orig.).

  3. The first ternary intermetallic Heusler nanoparticles: Co{sub 2}FeGa

    Energy Technology Data Exchange (ETDEWEB)

    Basit, Lubna; Yella, Aswani; Ksenofontov, Vadim; Fecher, Gerhard H.; Felser, Claudia [Institute of Inorganic and Analytical Chemistry, Johannes-Gutenberg-University, Mainz (Germany); Nepijko, Sergej A. [Institute of Physics, Johannes-Gutenberg-University, Mainz (Germany)

    2008-07-01

    Synthesis of materials with controlled particle size on the nanometer scale is an active area in the field of materials research. With the control over particle size, the electronic and magnetic properties of materials can be easily tuned. To study the effect of nanometer dimensions on the properties of Heusler alloys, a first example of Heusler nanoparticles is presented. Co{sub 2}FeGa Heusler nanoparticles were produced by reducing a methanol impregnated mixture of CoCl{sub 2}.6H{sub 2}O, Fe(NO{sub 3}){sub 3}.9H{sub 2}O, and Ga(NO{sub 3}){sub 3}.xH{sub 2}O after loading on fumed silica. The dried samples were heated under pure H{sub 2} gas at 900 C. The synthesized Co{sub 2}FeGa Heusler nanoparticles were characterized by HRTEM, XRD and Moessbauer spectroscopy. All peaks of the XRD pattern can be attributed to a L2{sub 1} Heusler structure with a lattice constant of a=4.37 A. The size of the particles, as determined by transmission electron microscopy, is between 16 nm and 20 nm. The ferromagnetic behaviour of the particles as determined by the SQUID measurements is presented and compared with the bulk Co{sub 2}FeGa Heusler alloy.

  4. Particle reduction strategies - PAREST. Evaluation of emission reduction scenarios using chemical transport calculations. PM10- and NO{sub 2}-immission contributions in Germany. Wood combustion in small combustion systems; installations of the 13th and 17th BImSchV (Federal Immission Control Act). Sub-report.; Strategien zur Verminderung der Feinstaubbelastung - PAREST. Bewertung von Emissionsminderungsszenarien mit Hilfe chemischer Transportberechnungen. PM10- und NO{sub 2}-Immissionsbeitraege in Deutschland. Holzverbrennung in Kleinfeuerungsanlagen, Anlagen der 13. und 17. BImSchV. Teilbericht

    Energy Technology Data Exchange (ETDEWEB)

    Stern, Rainer [Freie Univ. Berlin (Germany). Inst. fuer Meteorologie, Troposphaerische Umweltforschung

    2013-06-15

    This report was prepared within the research project ''Particle reduction strategies - PAREST.'' In this paper with the chemical transport model REM CALGRID following questions were investigated: 1 What is the contribution of the wood-fired small combustion plants in Germany to the PM10- and NO {sub 2}-concentrations? 2 What is the contribution of the 13th and 17th BlmSchV covered installations to the PM10 and NO{sub 2} concentrations in Germany? [German] Der vorliegende Bericht wurde im Rahmen des Forschungs- und Entwicklungsvorhabens ''Strategien zur Verminderung der Feinstaubbelastung'' erstellt. In dem Beitrag werden mit dem chemischen Transportmodell REM-CALGRID folgende Fragestellungen untersucht: 1. Wie hoch ist der Beitrag der mit Holz beheizten Kleinfeuerungsanlagen in Deutschland zu den PM10- und den NO{sub 2}-Konzentrationen? 2. Wie hoch ist der Beitrag der von der 13. und 17. BImSchV erfassten Anlagen zu den PM10-und NO-2-Konzentrationen in Deutschland?.

  5. Solubilities of CO sub 2 and redox equilibria of Sb and As in Na sub 2 O-Sb sub 2 O sub m and Na sub 2 O-As sub 2 O sub m melts. Na sub 2 O Sb sub 2 O sub m , Na sub 2 O-As sub 2 O sub m kei yoyu slag no CO sub 2 yokairyo to Sb to As no fuzon jotai

    Energy Technology Data Exchange (ETDEWEB)

    Fukuyama, H. (Nagoya Univ., Nagoya (Japan). Graduate School); Katao, T. (Sumitomo Metal Industries Ltd., Osaka (Japan)); Ikitsu, Y. (Daido Steel Co. Ltd., Nagoya (Japan)); Fujisawa, T.; Yamauchi, C. (Nagoya Univ., Nagoya (Japan). Faculty of Engineering)

    1991-12-20

    Solubilities of CO{sub 2} in Na{sub 2}O-Sb{sub 2}O{sub m} and Na{sub 2}O-As{sub 2}O{sub m} melts and redox ratio of Sb and As melts are measured over the composition range of 1>N>0.7 under the partial pressures of CO{sub 2} and 0{sub 2} from 0.01 to 0.1MPa and from 0.005 to 1000Pa, respectively, at the temperature of 1423 and 1523K. Based on the result of the measurement, reaction equation is studied which governs the redox equilibria of Sb and As and the solubilities of CO{sub 2} in those melts. Sb in Na{sub 2}O-CO{sub 2}-Sb{sub 2}O{sub m} melts exists in pentavalent and trivalent states. In Na{sub 2}O- CO{sub 2}-As{sub 2}O{sub m} melts, pentavalent As is very stable in comparison to Sb, and most of As exists in the state of complex ion. However, with the increase in the content of As{sub 2}O{sub 5} in the melts, the evaporation reaction of trivalent As becomes significant. 6 refs., 11 figs., tab.

  6. Comparison study on photocatalytic oxidation of pharmaceuticals by TiO{sub 2}-Fe and TiO{sub 2}-reduced graphene oxide nanocomposites immobilized on optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Lu; Wang, Huiyao, E-mail: huiyao@nmsu.edu; Jiang, Wenbin; Mkaouar, Ahmed Radhi; Xu, Pei, E-mail: pxu@nmsu.edu

    2017-07-05

    Highlights: • Incorporating rGO or Fe{sup 3+} ions in TiO{sub 2} photocatalyst could enhance photocatalysis. • TiO{sub 2}-rGO exhibited higher photocatalytic activity under UV irradiation. • TiO{sub 2}-Fe demonstrated more suitable for visible light irradiation. • Reduced recombination rate contributed to enhanced photocatalysis of TiO{sub 2}-rGO. • Narrower band gap accounted for increased photocatalytic activity of TiO{sub 2}-Fe. - Abstract: Incorporating reduced graphene oxide (rGO) or Fe{sup 3+} ions in TiO{sub 2} photocatalyst could enhance photocatalytic degradation of organic contaminants in aqueous solutions. This study characterized the photocatalytic activities of TiO{sub 2}-Fe and TiO{sub 2}-rGO nanocomposites immobilized on optical fibers synthesized by polymer assisted hydrothermal deposition method. The photocatalysts presented a mixture phase of anatase and rutile in the TiO{sub 2}-rGO and TiO{sub 2}-Fe nanocomposites. Doping Fe into TiO{sub 2} particles (2.40 eV) could reduce more band gap energy than incorporating rGO (2.85 eV), thereby enhancing utilization efficiency of visible light. Incorporating Fe and rGO in TiO{sub 2} decreased significantly the intensity of TiO{sub 2} photoluminescence signals and enhanced the separation rate of photo-induced charge carriers. Photocatalytic performance of the synthesized nanocomposites was measured by the degradation of three pharmaceuticals under UV and visible light irradiation, including carbamazepine, ibuprofen, and sulfamethoxazole. TiO{sub 2}-rGO exhibited higher photocatalytic activity for the degradation of pharmaceuticals under UV irradiation, while TiO{sub 2}-Fe demonstrated more suitable for visible light oxidation. The results suggested that the enhanced photocatalytic performance of TiO{sub 2}-rGO could be attributed to reduced recombination rate of photoexcited electrons-hole pairs, but for TiO{sub 2}-Fe nanocomposite, narrower band gap would contribute to increased photocatalytic

  7. Synthesis and characterization of TiO{sub 2}/Fe{sub 2}O{sub 3} core-shell nanocomposition film and their photoelectrochemical property

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Hui [State Key Laboratory of Superhard Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Fu Wuyou, E-mail: fuwy56@163.com [State Key Laboratory of Superhard Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Yang Haibin; Xu Yang; Zhao Wenyan; Zhang Yanyan; Chen Hui; Jing Qiang; Qi Xuefeng; Cao Jing; Zhou Xiaoming; Li Yixing [State Key Laboratory of Superhard Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)

    2011-08-15

    TiO{sub 2}/Fe{sub 2}O{sub 3} core-shell nanocomposition film has been fabricated via two-step method. TiO{sub 2} nanorod arrays are synthesized by a facile hydrothermal method, and followed by Fe{sub 2}O{sub 3} nanoparticles deposited on TiO{sub 2} nanorod arrays through an ordinary chemical bath deposition. The phase structures, morphologies, particle size, chemical compositions of the composites have been characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and ultraviolet-visible (UV-vis) spectrophotometer. The results confirm that Fe{sub 2}O{sub 3} nanoparticles of mean size ca. 10 nm coated on the surface of TiO2 NRs. After depositing Fe{sub 2}O{sub 3}, UV-vis absorption property is induces the shift to the visible-light range, the annealing temperature of 600 {sup o}C is the best condition for UV-vis absorption property of TiO{sub 2}/Fe{sub 2}O{sub 3} nanocomposite film, and increasing Fe content, optical activity are enhanced one by one. The photoelectrochemical (PEC) performances of the as-prepared composite nanorods are determined by measuring the photo-generated currents under illumination of UV-vis light. The TiO{sub 2} NRs modified by Fe{sub 2}O{sub 3} show the photocurrent value of 1.36 mA/cm{sup 2} at 0 V vs Ag/AgCl, which is higher than those of unmodified TiO{sub 2} NRs.

  8. Refinement of Mg{sub 2}Si reinforcement in a commercial Al–20%Mg{sub 2}Si in-situ composite with bismuth, antimony and strontium

    Energy Technology Data Exchange (ETDEWEB)

    Nordin, Nur Azmah; Farahany, Saeed, E-mail: saeedfarahany@gmail.com; Ourdjini, Ali; Abu Bakar, Tuty Asma; Hamzah, Esah

    2013-12-15

    Refinement by addition elements of Al–Mg{sub 2}Si alloys is known to result in a change of primary Mg{sub 2}Si morphology. In this paper, the effects of Bi, Sb and Sr on the characteristic parameters of Al–20%Mg{sub 2}Si in-situ composite have been investigated by computer aided cooling curve thermal analysis and microstructural inspection. Size, density and aspect ratio measurements showed that additions of 0.4 wt.% Bi, 0.8 wt.% Sb and 0.01 wt.% Sr refined the Mg{sub 2}Si reinforcement. Exceeding these concentrations, however, resulted in coarsening of Mg{sub 2}Si particles with no change in the morphology. The results also showed that addition elements caused a decrease in the nucleation and growth temperatures of Mg{sub 2}Si particles. The refining effect of Bi, Sb and Sr is likely to be related to the effect of oxide bifilms suspended in the composite melt as favored nucleation substrates for Mg{sub 2}Si particles. - Highlight: • 0.4 wt.%, 0.8 wt.% and 0.01 wt.% is the optimum content for Bi, Sb and Sr addition. • Exceeding optimum concentration resulted in the coarsening of reinforcements. • Nucleation and growth temperatures decrease with addition of Bi, Sb and Sr. • The refining effect of Bi, Sb and Sr is likely to be related to the oxide bifilms.

  9. Fragmentation of the CH{sub 2}Cl{sub 2} molecule by atto second proton beams and synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Alcantara, K.F.; Gomes, A.H.A.; Soriano, S.; Oliveira, V.; Sigaud, L.; Wolf, W.; Rocha, A.B.; Santos, A.C.F. [Universidade Federal do Rio de Janeiro (IF/UFRJ), RJ (Brazil)

    2011-07-01

    Full text. The absorption of a V UV photon by a molecule or its interaction with a charged particle, gives rise to an efficient molecular fragmentation which presents many open theoretical questions. Measurements of the ion yield and energy distributions of the fragmentation products in an ion-molecule collision have provided useful information about the molecular structure, the amount of energy transferred from the incoming particle to the molecule, and how this energy is spread among the molecular states. In this work, we have carried out fragmentation studies of the CH{sub 2}Cl{sub 2} molecule by 12-90 eV photons and 0.2-2.0 MeV p{sup +} impact. The mass spectrum obtained between 12-20 eV photons closely resembles the mass spectrum for the same molecule measured at 70 eV electron impact energy . Two sets of cations are clearly observed: namely CH{sub n}Cl{sub 2}{sup +} (n= 0,1,2), which corresponds to the parent molecule and the corresponding fragments related to a loss of one or two hydrogen atoms, and CH{sub n}Cl{sup +}. On the other hand, the abundances in the proton induced fragmentation mass spectra do not drastically depend on the proton collision energy. The main changes in the relative contributions of the fragments are observed in the 200-400 keV energy impact. The parent ion, CH{sup 2}Cl{sub 2}{sup +} (CHCl{sub 2}{sup +}; CCl{sub 2}{sup +}) is the second dominant structure (21% to 32%) in the mass spectra, also increasing as the proton energy increases. As opposed to the heavier fragments, the contribution from lighter fragments (C{sup l}+ and CH{sub n}{sup +}) of the CH{sub 2}Cl{sub 2} molecule to the mass spectra tend to decrease in their relative intensity as the proton energy increases

  10. Atmospheric fate of CF sub 3 Br, CF sub 2 Br sub 2 , CF sub 2 ClBr, and CF sub 2 BrCF sub 2 Br

    Energy Technology Data Exchange (ETDEWEB)

    Burkholder, J.B.; Wilson, R.R.; Gierczak, T.; Talukdar, R.; McKeen, S.A.; Orlando, J.J.; Vaghjiani, G.L.; Ravishankara, A.R. (National Oceanic and Atmospheric Administration, Boulder, CO (USA) Univ. of Colorado, Boulder (USA))

    1991-03-20

    The temperature dependent UV absorption cross sections of the haloalkanes CF{sub 3}Br, CF{sub 2}ClBr, CF{sub 2}Br{sub 2}, and CF{sub 2}BrCF{sub 2} are reported. The UV absorption cross sections were measured over the temperature range 210 to 296 K and the wavelength range 190 to 320 nm. Upper limits of the rate coefficients for the reactions of OH with CF{sub 3}Br, CF{sub 2}Br{sub 2}, CF{sub 2}ClBr, and CF{sub 2}BrCF{sub 2}Br were also determined using both pulsed photolysis and flow tube techniques. The rate coefficients at 296 K were found to be <1.2 {times} 10{sup {minus}16}, <1.5 {times} 10{sup {minus}16}, <5.0 {times} 10{sup {minus}16}, and <1.5 {times} 10{sup {minus}16} cm{sup 3} molec{sup {minus}1} s{sup {minus}1} for CF{sub 3}Br, CF{sub 2}ClBr, CF{sub 2}BrCF{sub 2}Br, respectively. The UV absorption cross-section data and OH reaction rate coefficients of these species were combined with a one-dimensional model to yield atmospheric lifetimes of 65, 16, 3.2, and <20 years for CF{sub 3}Br, CF{sub 2}ClBr, CF{sub 2}Br{sub 2}, and CF{sub 2}BrCF{sub 2}Br, respectively.

  11. Synthesis and photoluminescent properties of Sr{sub (1−x)}Si{sub 2}O{sub 2}N{sub 2}: xEu{sup 2+} phosphor prepared by polymer metal complex method for WLEDs applications

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Dhia A., E-mail: dhia_hassan@yahoo.com [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Department of Chemistry, College of Education for Pure Science, University of Basrah, Basrah 61004 (Iraq); Xu, Jian; Chen, Yibin; Li, Langkai [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Zeng, Renjie, E-mail: rjzeng@xmu.edu.cn [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Fujian Key Lab of Advanced Special Materials, Xiamen University, Xiamen 361005 (China)

    2016-07-15

    Highlights: • SrSi{sub 2}O{sub 2}N{sub 2}: Eu{sup 2+} phosphor was prepared by polymer metal complex (pechini method). • The annealing time was decreased from 6 h in solid state method to 3 h. • The particles are crystalline and dispersed well with average size 6.5 μm. - Abstract: Green emitting Sr{sub (1−x)}Si{sub 2}O{sub 2}N{sub 2}: xEu{sup 2+} (x = 0, 0.02, 0.04, 0.06, 0.08 and 0.1) phosphors were synthesized by polymer metal complex or pechini method. The XRD results confirm the formation of a pure phase at 1400 °C for 3 h. The SEM and particles size results indicate that the prepared phosphor consists of a polyhedral crystalline shape with well dispersed and the average particle size around 6.5 μm. The maximum PL intensity was found at 0.04% Eu{sup 2+} with a wide emission band between 460 and 640 nm and a green emission peak at 531.4 nm. The external quantum efficiency of 0.04% Eu{sup 2+} sample was 43.13%. The results indicate that pechini method is an alternative way and close in efficiency to the solid state method to prepare SrSi{sub 2}O{sub 2}N{sub 2} phosphor with higher homogeneity and more uniform size distribution for near UV and blue region applications for white light emitting diodes WLEDs.

  12. Friction stir processed Al–TiO{sub 2} surface composites: Anodising behaviour and optical appearance

    Energy Technology Data Exchange (ETDEWEB)

    Gudla, Visweswara Chakravarthy, E-mail: chakri_gvc@yahoo.co.in [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Jensen, Flemming [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Simar, Aude [iMMC, Université Catholique de Louvain, Place Sainte Barbe 2, 1348 Louvain-la-Neuve (Belgium); Shabadi, Rajashekhara [Unité Matériaux et Transformations, Université Lille1, 59655 Villeneuve-d’Ascq (France); Ambat, Rajan [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

    2015-01-01

    Highlights: • Microstructure of friction stir processed Al–TiO{sub 2} surface composites after anodising. • Effect of sulphuric acid anodising parameters on optical appearance of anodised layer. • Partial to complete amorphization of TiO{sub 2} particles with increasing anodising voltage. • Unoxidized metallic Al “shadow region” below TiO{sub 2} particles at low anodising voltage. • Presence of coloured Ti{sub n}O{sub 2n−1} and light absorbing unoxidized metallic Al cause darkening of anodised layer. - Abstract: Multiple-pass friction stir processing (FSP) was employed to impregnate TiO{sub 2} (rutile) particles into the surface of an aluminium alloy. The surface composites of Al–TiO{sub 2} were then anodised in a sulphuric acid electrolyte. The effect of anodising parameters on the resulting optical appearance was investigated. Microstructural and morphological characterization was performed using scanning (SEM) and transmission electron microscopy (TEM), and X-ray diffraction (XRD). The surface appearance was analysed using an integrating sphere-spectrophotometer setup which measures the diffuse and total reflectance of light from the surface. Compared to samples without TiO{sub 2}, surface appearance after anodising of samples with TiO{sub 2} changed from dark to greyish white upon increasing the anodising voltage. This is attributed to the localized microstructural and morphological differences around the TiO{sub 2} powder particles incorporated into the anodic alumina matrix. The TiO{sub 2} powder particles in the FSP zone were partially or completely amorphized during the anodising process, and also electrochemically shadowed the anodising of underlying Al matrix.

  13. A facile approach to fabrication of novel CeO{sub 2}-TiO{sub 2} core-shell nanocomposite leads to excellent UV-shielding ability and lower catalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Bahadur, Newaz Mohammed, E-mail: nmbahadur@yahoo.com [Utsunomiya University, Laboratory of Powder Technology, Graduate School of Engineering, Venture Business Laboratry (Japan); Kurayama, Fumio [Utsunomiya University, Center for Optical Research and Education (Japan); Furusawa, Takeshi; Sato, Masahide [Utsunomiya University, Department of Advanced Interdisciplinary Sciences (Japan); Siddiquey, Iqbal Ahmed [Utsunomiya University, Laboratory of Powder Technology, Graduate School of Engineering, Venture Business Laboratry (Japan); Hossain, Md. Mufazzal [University of Dhaka, Department of Chemistry (Bangladesh); Suzuki, Noboru [Utsunomiya University, Laboratory of Powder Technology, Graduate School of Engineering, Venture Business Laboratry (Japan)

    2013-01-15

    This study reports the development of a fast and facile route for the synthesis of novel CeO{sub 2}-TiO{sub 2} core-shell nanocomposite particles using microwave (MW) irradiation of the mixture of commercial CeO{sub 2}, titanium-tetra-n-butoxide (TBOT) and aqueous ammonia. Solutions of TBOT in ethanol and ammonia were mixed with dispersed CeO{sub 2} nanoparticles in ethanol, and the mixture was rapidly MW irradiated at 70 Degree-Sign C for 2 min. The resulting nanocomposite particles were characterized in terms of phase, shell thickness, composition, surface charge, morphology, and chemical state of the elements by XRD, TEM, XPS, SEM, Zeta potential analyzer, XRF, and FT-IR. Conventional methods of the synthesis of CeO{sub 2}-TiO{sub 2} nanocomposite require a long time, and TiO{sub 2} is rarely found as a coated material. In contrast, the MW method was able to synthesize CeO{sub 2}-TiO{sub 2} core-shell nanocompsite particles within a very short time. CeO{sub 2}-TiO{sub 2} nanocomposite particles were fairly unaggregated with an average titania layer thickness of 2-5 nm. The obtained nanocomposites retained the crystalline cubic phase of CeO{sub 2}, and the phase of coated TiO{sub 2} was amorphous. The catalytic activities of uncoated and TiO{sub 2}-coated CeO{sub 2} nanoparticles for the oxidation of organic compounds were evaluated by the degradation study of methylene blue in air atmosphere at 403 K. The enhanced UV-shielding ability and visible transparency of the nanocomposite obtained by UV visible spectroscopic measurements suggested that the core-shell material has novel characteristics for using as a sunscreen material.

  14. Solar Powered CO.Sub.2 Conversion

    Science.gov (United States)

    Chen, Bin (Inventor)

    2016-01-01

    Methods and devices for reducing CO.sub.2 to produce hydrocarbons are disclosed. A device comprises a photoanode capable of splitting H.sub.2O into electrons, protons, and oxygen; an electrochemical cell cathode comprising an electro-catalyst capable of reducing CO.sub.2; H.sub.2O in contact with the surface of the photoanode; CO.sub.2 in contact with the surface of the cathode; and a proton-conducting medium positioned between the photoanode and the cathode. Electrical charges associated with the protons and the electrons move from the photoanode to the cathode, driven in part by a chemical potential difference sufficient to drive the electrochemical reduction of CO.sub.2 at the cathode. A light beam is the sole source of energy used to drive chemical reactions. The photoanode can comprise TiO.sub.2 nanowires or nanotubes, and can also include WO.sub.3 nanowires or nanotubes, quantum dots of CdS or PbS, and Ag or Au nanostructures. The cathode can comprise a conductive gas diffusion layer with nanostructures of an electro-catalyst such as Cu or Co.

  15. Biocompatibility and bioactivity of PDLLA/TiO{sub 2} and PDLLA/TiO{sub 2}/Bioglass (registered) nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Wei, J.; Chen, Q.Z. [Department of Materials, Imperial College London, South Kensington Campus, London SW7 2BP (United Kingdom); Stevens, M.M. [Department of Materials, Imperial College London, South Kensington Campus, London SW7 2BP (United Kingdom); Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Roether, J.A. [Department of Materials, Imperial College London, South Kensington Campus, London SW7 2BP (United Kingdom); Boccaccini, A.R. [Department of Materials, Imperial College London, South Kensington Campus, London SW7 2BP (United Kingdom); Composites Centre, Imperial College London, London SW7 2BP (United Kingdom)], E-mail: a.boccaccini@imperial.ac.uk

    2008-01-10

    Biocompatibility and bioactivity of polymer matrix composites containing titanium dioxide (TiO{sub 2}) nanoparticles were investigated. The solvent casting method was used to prepare poly (D,L-lactic acid) (PDLLA) films with 0 and 20 wt.% TiO{sub 2} nanoparticles and with 20 wt.% TiO{sub 2} mixed with 5 wt.% micrometre-sized (< 5 {mu}m) Bioglass (registered) particles. The samples were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy Dispersive X-ray (EDX) analyses. A Zygo (registered) light interferometer was used to examine the surface roughness of the samples. The bioactivity and the surface reactivity of the materials were determined by investigating the formation of hydroxyapatite (HA) on the surface of samples upon immersion in simulated body fluid (SBF) for up to 28 days. Heterogeneous distributed HA crystals were found on composite films containing TiO{sub 2} after 21 days exposure to SBF. Cell cytotoxicity and viability were determined by using live/dead and MTS assay on osteoblast-like MG-63 cells. The PDLLA films containing different concentrations of TiO{sub 2} and Bioglass (registered) particulate inclusions showed no effect on cell viability in live/dead assay after incubation period of 7 days. All three groups of samples demonstrated significant increase in relative metabolic activity in MTS assay after 7 days incubation (while a slower proliferation rate was obtained for cells on the PDLLA film containing both TiO{sub 2} and Bioglass (registered) compared to the Thermanox (registered) control). The bioactive behaviour of the nanocomposites may make them attractive materials for fabrication of tissue engineering scaffolds.

  16. Lead nitroprusside: A new precursor for the synthesis of the multiferroic Pb{sub 2}Fe{sub 2}O{sub 5,} an anion-deficient perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Diego M. [Instituto de Química Inorgánica, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, 4000 San Miguel de Tucumán (Argentina); Nieva, Gladys [Centro Atómico Bariloche, Instituto Balseiro, Comisión Nacional de Energía Atómica, Universidad Nacional de Cuyo, 8400 San Carlos de Bariloche (Argentina); Franco, Diego G. [Centro Atómico Bariloche, Instituto Balseiro, Comisión Nacional de Energía Atómica, Universidad Nacional de Cuyo, 8400 San Carlos de Bariloche (Argentina); Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC – CONICET), Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba (Argentina); Gómez, María Inés [Instituto de Química Inorgánica, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, 4000 San Miguel de Tucumán (Argentina); and others

    2013-08-15

    In order to investigate the formation of multiferroic oxide Pb{sub 2}Fe{sub 2}O{sub 5}, the thermal decomposition of Pb[Fe(CN){sub 5}NO] has been studied. The complex precursor and the thermal decomposition products were characterized by IR and Raman spectroscopy, thermal analysis, powder X-ray diffraction (PXRD), scanning electron microscopy and magnetic measurements. The crystal structure of Pb[Fe(CN){sub 5}NO] was refined by Rietveld analysis. It crystallizes in the orthorhombic system, space group Pnma. The thermal decomposition in air produces highly pure Pb{sub 2}Fe{sub 2}O{sub 5} as final product. This oxide is an anion deficient perovskite with an incommensurate superstructure. The magnetic measurements confirm that Pb{sub 2}Fe{sub 2}O{sub 5} shows a weak ferromagnetic signal probably due to disorder in the perfect antiferromagnetic structure or spin canting. The estimated ordering temperature from the fit of a phenomenological model was 520 K. The SEM images reveal that the thermal decomposition of Pb[Fe(CN){sub 5}NO] produces Pb{sub 2}Fe{sub 2}O{sub 5} with small particle size. - Highlights: • Pb[Fe(CN){sub 5}NO] was synthesized and characterized. • Pb[Fe(CN){sub 5}NO] belongs to orthorhombic crystal system, space group Pnma. • Pb{sub 2}Fe{sub 2}O{sub 5} was obtained by thermal decomposition of Pb[Fe(CN){sub 5}NO]. • Pb{sub 2}Fe{sub 2}O{sub 5} is a weak ferromagnet due to spin canting. • Ordering temperature of Pb{sub 2}Fe{sub 2}O{sub 5} from the fit of a phenomenological model was 520 K. - Graphical abstract: Field cooling (FC) and zero field cooling (ZFC) magnetization curves at H = 10 and 1000 Oe for Pb{sub 2}Fe{sub 2}O{sub 5} obtained at 750 °C. Remnant magnetization after applying H = 1 T, FC procedure at 0.8 Oe. The fitted expression (see text) yield an ordering temperature T{sub o} = 520 K. Display Omitted.

  17. The trade-off between N{sub 2}, NO, and N{sub 2}O under fluidized bed combustor conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wartha, C.; Winter, F.; Hofbauer, H.

    1999-07-01

    NO and N{sub 2}O are harmful pollutants. Under fluidized bed combustor conditions the nitrogen of the solid fuel is partly converted to these species. The trade-off between N{sub 2}O depends on the fuel and fuel characteristics, the complex homogeneous and heterogeneous formation and destruction paths, temperature and residence times, and so forth. Because of these complex interrelations, it is necessary to study these processes separately and to analyze their relative importance. To obtain a better understanding of the formation and destruction paths of NO and N{sub 2}O, comprehensive studies have been performed in a laboratory-scale fluidized bed reactor optimized to obtain formation rates. The influence of the temperature and radicals on the NO and N{sub 2}O formation from HCN and NH{sub 3} and destruction reactions were studied. The results show that N{sub 2}O is formed only from HCN. Oxidation of NH{sub 3} forms NO and N{sub 2}O, HCN forms NO, N{sub 2}O, and N{sub 2}. 30 to 70% of NH{sub 3} are converted to N{sub 2} depending on bed temperature. In the case of HCN only 5 to 25% are converted to N{sub 2}. At temperatures below 800 C NO reacts with CH{sub 4} oxidation products to NO{sub 2}. Tests with HCN show that HCN conversion starts already at 700 C in the fluidized bed catalyzed by sand, N{sub 2}O is formed in significant amounts only in the presence of CH{sub 4}. The results of the NO and N{sub 2}O destruction tests show that the thermal mechanism is of minor importance. At 900 C N{sub 2}O destruction with H radicals can be seen. N{sub 2}O formation shows a maximum at 850 C. The NH{sub 3}, HCN, NO, and N{sub 2}O single particle formation characteristics of coke, bituminous coal, peat and spruce wood can be explained well with the results obtained from the gas reaction tests.

  18. A [Mo{sub 2}O{sub 2}S{sub 2}]-based ring system incorporating tartrate as the bridging ligand. Synthesis, structure and catalytic activity of Cs{sub 4}[Mo{sub 2}O{sub 2}(μ-S){sub 2}]{sub 2}(μ{sub 4}-tart){sub 2} (tart=[C{sub 4}H{sub 2}O{sub 6}]{sup 4-})

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Ting-Ting; Cui, Yu-Jie; Xin, Zhifeng; Jia, Ai-Quan; Zhang, Qian-Feng [Anhui Univ. of Technology, Anhui (China). Inst. of Molecular Engineering and Applied Chemistry and Anhui Province Key Lab. of Metallurgy Engineering and Resources Recycling

    2017-08-01

    Treatment of [Mo{sub 2}S{sub 2}O{sub 2}(H{sub 2}O){sub 6}]{sup 2+} with racemic tartaric acid (tartH{sub 4}) in the presence of sodium hydroxide and cesium chloride in aqueous solution led to the isolation of a new tetra-molybdenum ring cluster Cs{sub 4}[Mo{sub 2}O{sub 2}(μ-S){sub 2}]{sub 2}(μ{sub 4}-tart){sub 2}. The cyclic cluster polyanion consists of two dinuclear [Mo{sub 2}O{sub 2}(μ-S){sub 2}]{sup 2+} moieties and two bridging tart{sup 4-} ligands. The cyclic polyoxothiomolybdate cluster, supported on the mesoporous silica SBA-15, was tested for heterogenerous catalysis in thiophene hydrodesulfurization.

  19. SERS of semiconducting nanoparticles (TIO{sub 2} hybrid composites).

    Energy Technology Data Exchange (ETDEWEB)

    Rajh, T.; Musumeci, A.; Gosztola, D.; Schiller, T.; Dimitrijevic, N. M.; Mujica, V.; Martin, D.; Center for Nanoscale Materials

    2009-05-06

    Raman scattering of molecules adsorbed on the surface of TiO{sub 2} nanoparticles was investigated. We find strong enhancement of Raman scattering in hybrid composites that exhibit charge transfer absorption with TiO{sub 2} nanoparticles. An enhancement factor up to {approx}10{sup 3} was observed in the solutions containing TiO{sub 2} nanoparticles and biomolecules, including the important class of neurotransmitters such as dopamine and dopac (3,4-dihydroxy-phenylacetic acid). Only selected vibrations are enhanced, indicating molecular specificity due to distinct binding and orientation of the biomolecules coupled to the TiO{sub 2} surface. All enhanced modes are associated with the asymmetric vibrations of attached molecules that lower the symmetry of the charge transfer complex. The intensity and the energy of selected vibrations are dependent on the size and shape of nanoparticle support. Moreover, we show that localization of the charge in quantized nanoparticles (2 nm), demonstrated as the blue shift of particle absorption, diminishes SERS enhancement. Importantly, the smallest concentration of adsorbed molecules shows the largest Raman enhancements suggesting the possibility for high sensitivity of this system in the detection of biomolecules that form a charge transfer complex with metal oxide nanoparticles. The wavelength-dependent properties of a hybrid composite suggest a Raman resonant state. Adsorbed molecules that do not show a charge transfer complex show weak enhancements probably due to the dielectric cavity effect.

  20. Oxovanadium alkoxides: Structure, reactivity, and sup 51 V NMR characteristics. Crystal and molecular structures of VO(OCH sub 2 CH sub 2 Cl) sub 3 and VOCl sub 2 (THF) sub 2 H sub 2 O

    Energy Technology Data Exchange (ETDEWEB)

    Priebsch, W.; Rehder, D. (Universitaet Hamburg (West Germany))

    1990-08-08

    The vanadyl esters VO(OR){sub 3} (R = Me, Et, Pr, iPr, sBu, tBu, CH{sub 2}CH{sub 2}F, CH{sub 2}CH{sub 2}Cl, CH{sub 2}CCl{sub 3}) have been prepared and their association properties in pentane investigated by {sup 51}V NMR. Limiting (low concentration) {delta}({sup 51}V) values depend on the bulk of R (highest {sup 51}V shielding for tBu). Shielding decreases with increasing concentration (more pronounced for small R groups), owing to the formation of oligomers, probably connected by {mu}-OR groups. The X-ray diffraction study of VO(OCH{sub 2}CH{sub 2}Cl){sub 3} reveals dimer association of molecules belonging to adjacent unit cells via long V-OR bonds (226.1 (2) pm), and a trigonal-bipyramidal geometry for each monomeric unit. From the reaction between VOCl{sub 3} and diols (glycol, 1,3-propanediol, 1,2-, 2,3-, 1,3-, and 1,4-butanediol), complexes are obtained that contain the {l brace}VOCl(OR){sub 2}{r brace} and {l brace}VOCl{sub 2}OR{r brace} moieties and the alcohol coordinated in the monofunctional or bifunctional (chelating and bridging) mode. The {sup 51}V NMR spectrum of VOCl{sub 2}OCH(Me)CH(Me)OH exhibits resolved {sup 51}V-{sup 35,37}Cl coupling: J({sup 51}V-{sup 35}Cl) = 100 Hz; J({sup 51}V-{sup 37}Cl) = 83 Hz. V{sup V}OCl{sub 2}(OCH{sub 2}CH{sub 2}CH{sub 2}OH) reacts with 1,4-butanediol to form V{sup IV}OCl{sub 2}(THF){sub 2}(OH{sub 2}). In the presence of COCL{sub 3}, THF undergoes ether splitting, chlorination, and coordination to vanadium to yield VOCl{sub 2}(OCH{sub 2}CH{sub 2}CH{sub 2}CH{sub 2}Cl). 35 refs., 7 figs., 7 tabs.

  1. Effect of symbiotic compound Fe{sub 2}P{sub 2}O{sub 7} on electrochemical performance of LiFePO{sub 4}/C cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shuxin, E-mail: liushuxin88@126.com [School of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang, Sichuan 621000 (China); Gu, Chunlei [School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei 050018 (China); Wang, Haibin [School of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang, Sichuan 621000 (China); Liu, Ruijiang [School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Wang, Hong; He, Jichuan [School of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang, Sichuan 621000 (China)

    2015-10-15

    In order to study the effect of symbiotic compound Fe{sub 2}P{sub 2}O{sub 7} on electrochemical performance of LiFePO{sub 4}/C cathode materials, the LiFePO{sub 4}/Fe{sub 2}P{sub 2}O{sub 7}/C cathode materials were synthesized by in-situ synthesis method. The phase compositions and microstructures of the products were characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscope (FESEM). Results indicate that the existence of Fe{sub 2}P{sub 2}O{sub 7} does not alter LiFePO{sub 4} crystal structure and the existence of Fe{sub 2}P{sub 2}O{sub 7} decreases the particles size of LiFePO{sub 4}. The electrochemical behavior of cathode materials was analyzed using galvanostatic measurement and cyclic voltammetry (CV). The results show that the existence of Fe{sub 2}P{sub 2}O{sub 7} improves electrochemical performance of LiFePO{sub 4} cathode materials in specific capability and lithium ion diffusion rate. The charge–discharge specific capacity and apparent lithium ion diffusion coefficient increase with Fe{sub 2}P{sub 2}O{sub 7} content and maximizes around the Fe{sub 2}P{sub 2}O{sub 7} content is 5 wt%. It has been had further proved that the Fe{sub 2}P{sub 2}O{sub 7} adding enhances the lithium ion transport to improve the electrochemical performance of LiFePO{sub 4} cathode materials. However, excessive Fe{sub 2}P{sub 2}O{sub 7} will block the electron transfer pathway and affect the electrochemical performances of LiFePO{sub 4} directly. - Graphical abstract: The LiFePO{sub 4}/Fe{sub 2}P{sub 2}O{sub 7}/C cathode materials were synthesized by in-situ synthesis method. The existence of Fe{sub 2}P{sub 2}O{sub 7} does not alter LiFePO{sub 4} crystal structure and the existence of Fe{sub 2}P{sub 2}O{sub 7} decreases the particles size of LiFePO{sub 4}. The charge–discharge specific capacity and apparent lithium ion diffusion coefficient increase with Fe{sub 2}P{sub 2}O{sub 7} content. However, excessive Fe{sub 2}P{sub 2}O{sub 7} will

  2. Effects of TiO{sub 2} nanoparticles on the NO{sub 2}{sup -} levels in cell culture media analysed by Griess colorimetric methods

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, Traian, E-mail: tr.popescu@gmail.com [National Institute of Materials Physics (Romania); Lupu, Andreea R. [University of Bucharest, Faculty of Biology (Romania); Diamandescu, Lucian; Tarabasanu-Mihaila, Doina; Teodorescu, Valentin S. [National Institute of Materials Physics (Romania); Raditoiu, Valentin; Purcar, Violeta [National Research and Development Institute for Chemistry and Petrochemistry (ICECHIM) (Romania); Vlaicu, Aurel M. [National Institute of Materials Physics (Romania)

    2013-02-15

    The Griess assay has been used to determine the possible changes in the measured NO{sub 2}{sup -} concentrations induced by TiO{sub 2} nanoparticles in three types of nitrite-containing samples: aqueous NaNO{sub 2} solutions with known concentrations, and two types of cell culture media-Roswell Park Memorial Institute medium (RPMI-1640) and Dulbecco's Modified Eagle Medium (DMEM-F12) used either as delivered or enriched in NO{sub 2}{sup -} by NaNO{sub 2} addition. We have used three types of titania with average particle sizes between 10 and 30 nm: Degussa P25 and two other samples (undoped and Fe{sup 3+}-doped anatase TiO{sub 2}) synthesised by a hydrothermal route in our laboratory. The structural, morphological, optical and physicochemical characteristics of the used materials have been studied by X-ray diffraction, transmission electron microscopy (EDX), Moessbauer spectroscopy, Brunauer-Emmett-Teller nitrogen adsorption, UV-Vis reflectance spectroscopy, dynamic light scattering and diffuse reflectance infrared Fourier transform spectroscopy. The opacity and sedimentation behaviour of the studied TiO{sub 2} suspensions have been investigated by photometric attenuance measurements at 540 nm. To account for the photocatalytic properties of titania in a biologically relevant context, multiple Griess tests have been performed under controlled exposure to laboratory natural daylight illumination. The results show significant variations of light attenuance (associated with NO{sub 2}{sup -} concentrations in the Griess test) depending on the opacity, sedimentation behaviour, NO{sub 2}{sup -} adsorption and photocatalytic properties of the tested TiO{sub 2} nanomaterials. These findings identify material characteristics recommended to be considered when analysing the results of Griess tests performed in biological studies involving TiO{sub 2} nanoparticles.

  3. Electron microscopy investigations of metal-support interaction effects in M/Y{sub 2}O{sub 3} and M/ZrO{sub 2} thin films (M=Cu, Ni)

    Energy Technology Data Exchange (ETDEWEB)

    Thalinger, Ramona [Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck (Austria); Stöger-Pollach, Michael; Hetaba, Walid [University Service Center for Transmission Electron Microscopy (USTEM), Vienna University of Technology, A-1040 Vienna (Austria); Feuerbacher, Michael [Ernst Ruska Zentrum und Peter Grünberg Institut, Forschungszentrum Jülich, 52425 Jülich (Germany); Klötzer, Bernhard [Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck (Austria); Penner, Simon, E-mail: simon.penner@uibk.ac.at [Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck (Austria)

    2013-12-16

    Model systems of the clean and pure oxides Y{sub 2}O{sub 3} and ZrO{sub 2}, as well as Cu/Cu{sub 2}O and Ni/NiO particles embedded in the respective oxides have been used to study the reduction behavior of the oxides and the eventually associated metal-support interaction effects in oxide-supported systems. Particular emphasis has also been given to the influence of the phase transformation in ZrO{sub 2}-containing systems on metal-support interaction. Whereas Y{sub 2}O{sub 3} has been found to be an outstandingly structurally and thermally stable oxide even upon reduction in hydrogen up to 1073 K, ZrO{sub 2} was found to undergo a series of phase transformations from amorphous ZrO{sub 2} to polycrystalline tetragonal ZrO{sub 2} (∼673 K) and subsequently to monoclinic ZrO{sub 2} (above 873 K). Both phase transformations were found to be basically dependent on gas partial pressure and annealing rate. However, substantial reduction of the oxides did not take place during the phase transformations. In turn, both Cu- and Ni-containing systems were not observed to be substantially affected by any (strong) metal-support interaction effects such as encapsulation by sub-stoichiometric oxides or reductive formation of intermetallic phases, at least up to temperatures of 1073 K. Equally, for the ZrO{sub 2}-containing systems, also the phase transformations occurring at elevated temperatures did not cause structural or thermo-chemical alterations of the Cu or Ni-particles. Differences in the metal-support interaction between Cu- and Ni-particles have only been obtained in the structural “reference” systems, that is, if supported on SiO{sub 2}. Whereas Cu/Cu{sub 2}O particles on SiO{sub 2} are basically unaffected by the reductive treatment at elevated temperatures, a Ni{sub 3}Si{sub 2} intermetallic phase is formed if SiO{sub 2}-supported Ni/NiO particles are treated in hydrogen at 673 K and above. - Highlights: • Gas partial-pressure and annealing rate

  4. The comparison of photocatalytic activity of synthesized TiO{sub 2} and ZrO{sub 2} nanosize onto wool fibers

    Energy Technology Data Exchange (ETDEWEB)

    Moafi, Hadi Fallah [Department of Chemistry, Faculty of Science, University of Guilan, Namjoo Street, P.O. Box 1914, Rasht (Iran, Islamic Republic of); Shojaie, Abdollah Fallah, E-mail: a.f.shojaie@guilan.ac.ir [Department of Chemistry, Faculty of Science, University of Guilan, Namjoo Street, P.O. Box 1914, Rasht (Iran, Islamic Republic of); Zanjanchi, Mohammad Ali [Department of Chemistry, Faculty of Science, University of Guilan, Namjoo Street, P.O. Box 1914, Rasht (Iran, Islamic Republic of)

    2010-04-15

    TiO{sub 2} and ZrO{sub 2} nanocrystals were successfully synthesized and deposited onto wool fibers using the sol-gel technique at low temperature. The photocatalytic activities of TiO{sub 2}-coated and ZrO{sub 2}-coated wool fibers were measured by studying photodegradation of methylene blue and eosin yellowish dyes. The initial and the treated samples were characterized by several techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and X-ray diffraction. The TEM study shows dispersed particles with 10-30 nm in size for TiO{sub 2}-coated and 20-40 nm in size for ZrO{sub 2}-coated samples on the fiber surface. Comparison of the photocatalytic activity of the coated samples reveals superiority of TiO{sub 2} modified sample with respect to that of ZrO{sub 2} for degradation of both dyes. Our observations indicate that by applying this technique to the fabrics, self-cleaning materials could be designed for practical application.

  5. Study the effect of mechanical alloying parameters on synthesis of Cr{sub 2}Nb–Al{sub 2}O{sub 3} nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Shayesteh, Payam, E-mail: shayesteh.payam@gmail.com; Mirdamadi, Shamseddin; Razavi, Hossein

    2014-01-01

    Graphical abstract: - Highlights: • Cr{sub 2}Nb–Al{sub 2}O{sub 3} nanocomposite synthesized through MA. • Effect of BPR, rotating speed, milling time and PCA concentration investigated. • After annealing at 1100 °C crystalline phase were appeared. • Williamson–Hall analysis was used in order to study the grain size of nano composite. - Abstract: In this study, Cr{sub 2}Nb–20 vol.% Al{sub 2}O{sub 3} nanocomposite was prepared successfully by mechanochemical reaction between Al, Nb and Cr{sub 2}O{sub 3} powders. Amorphization of powder occurred during mechanical alloying because of high energy collisions between powders and steel balls in milling container which transfer high degree of energy to powders. Therefore, annealing was needed to form crystalline phases. The influence of different mechanical alloying parameters such as BPR, rotating speed, milling time and PCA concentration on synthesis of composite material were investigated. After mechanical alloying, the powder was encapsulated in quartz and then annealed at 1100 °C for 3 h. After annealing, 3 different phases were appeared (Cr{sub 2}Nb (cubic), Cr{sub 2}Nb (hexagonal) and α-Al{sub 2}O{sub 3}). The structural changes of powder particles during mechanical alloying were studied by X-ray diffractometry (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM)

  6. Synthesis, structural and electrical properties of [C{sub 2}H{sub 10}N{sub 2}][(SnCl(NCS){sub 2}]{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Karoui, Sahel [Laboratoire genie de materiaux et environnement, ENIS, BP.1173,3038- Sfax, Universite de Sfax (Tunisia); Kamoun, Slaheddine, E-mail: slah.kamoun@gmail.com [Laboratoire genie de materiaux et environnement, ENIS, BP.1173,3038- Sfax, Universite de Sfax (Tunisia); Jouini, Amor [Laboratoire de Chimie du Solide, Departement de Chimie, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia)

    2013-01-15

    Synthesis, structural and electrical properties are given for a new organic stannous pseudo halide material. The structure of the [C{sub 2}H{sub 10}N{sub 2}][(SnCl(NCS){sub 2}]{sub 2} reveals that the adjacent Sn(II) centres are bridged by a pair of SCN{sup -} anions to form a 1-D array giving rise to the anionic chains (SnCl(NCS){sub 2}){sub n}{sup n-}. These chains are themselves interconnected by means of N-H Horizontal-Ellipsis Cl(S) hydrogen bonds originating from the organic cation [(NH{sub 3}){sub 2}(CH{sub 2}){sub 2}]{sup 2+}. The AC impedance measurements were performed as a function of both frequency and temperature. The electrical conduction and dielectric relaxation have been studied. The activation energy associated with the electrical relaxation determined from the electric modulus spectra was found close to that of the activation energy obtained for DC conductivity. The conduction mechanisms are attributed to the quantum mechanical tunneling model in phase I and to the proton hopping among hydrogen vacancies in phase II. - Graphical abstract: Atomic coordination in [C2H10N2][SnCl(NCS)2)2]. Highlights: Black-Right-Pointing-Pointer X-ray diffraction analysis shows the 1D network character of the structure. Black-Right-Pointing-Pointer DSC experiments show a phase transition at 336 K. Black-Right-Pointing-Pointer The AC conductivity is interpreted in terms of Jonsher's law. Black-Right-Pointing-Pointer Two conduction mechanisms are proposed for phase I and II.

  7. Thermal transport properties of MoS <sub>2 and MoSe <sub>2 monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Kandemir, Ali; Yapicioglu, Haluk; Kinaci, Alper; Çağın, Tahir; Sevik, Cem

    2016-01-11

    Isolation of single to few layer transition metal dichalgogenides open alternate venues in application of 2 dimensional materials to nanoelectronics. Either for general overheating issues or specific application in thermoelectric devices, the characterization of the thermal transport in these new low dimensional materials is needed for their efficient implementation. In this study, lattice thermal conductivities of single layer MoS<sub>2 and MoSe<sub>2 are evaluated using classical molecular dynamics method. The interactions between atoms are defined by Stillinger-Weber type empirical potentials that are developed to represent structural, mechanical, and vibrational properties of the given materials. In parameterization of the potentials, a stochastic optimization algorithm, namely particle swarm optimization is utilized. The final parameter sets produce quite consistent results with DFT in terms of lattice parameters, bond distances, elastic constants and vibrational properties of both single layer MoS<sub>2 and MoSe<sub>2. The predicted thermal properties of both materials are in very good agreement with earlier first principles calculations. The discrepancies between calculations and experimental measurements are most likely to be caused by pristine nature of the structures in our simulations.

  8. Improvement of CO sub 2 flood performance

    Energy Technology Data Exchange (ETDEWEB)

    Martin, D.F.; Heller, J.P.

    1991-06-01

    This is the final report of a six-year research project devoted to the study of processes of oil displacement using dense carbon dioxide. The topics studied have included phase behavior and physical properties of mixtures of crude oil with CO{sub 2}, the phenomena involved in the displacement of oil through reservoir rock under oilfield conditions, the influence of stabilized lamella or CO{sub 2}-foam on this displacement and the development of computer programs to simulate the displacement. In addition, the occurrence of nonuniformities in the displacement pattern has also been considered. The effect on displacement of permeability heterogeneities in the reservoir have been studied geostatistically and by direct numerical modelling. Displacement nonuniformities that are induced by viscosity and density differences between displaced and displacing fluids have also been considered, and efforts are described for the development of two different types of additive for purposes of mobility control of CO{sub 2} floods. One of these is the so-called CO{sub 2}-foam, formed by simultaneous flow through the formation of dense CO{sub 2} with a water solution of a special surfactant. The second type under development in the project is known as direct thickener, and consists of a polymer that is soluble in dense CO{sub 2} and able to viscosify it. Significant progress is reported on all of the topics mentioned above. 174 refs., 186 figs., 41 tabs.

  9. Field verification of CO sub 2 -foam

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F.D.; Heller, J.P.; Weiss, W.W.

    1992-05-01

    In September 1989, the Petroleum Recovery Research Center (PRRC), a division of New Mexico Institute of Mining and Technology, received a grant from the US Department of Energy (DOE) for a project entitled Field Verification of CO{sub 2} Foam.'' The grant provided for an extension of the PRRC laboratory work to a field testing stage to be performed in collaboration with an oil producer actively conducting a CO{sub 2} flood. The objectives of this project are to: (1) conduct reservoir studies, laboratory tests, simulation runs, and field tests to evaluate the use of foam for mobility control or fluid diversion in a New Mexico CO{sub 2} flood, and (2) evaluate the concept of CO{sub 2}-foam in the field by using a reservoir where CO{sub 2} flooding is ongoing, characterizing the reservoir, modeling the process, and monitoring performance of the field test. Seven tasks were identified for the successful completion of the project: (1) evaluate and select a field site, (2) develop an initial site- specific plan, (3) conduct laboratory CO{sub 2}-foam mobility tests, (4) perform reservoir simulations, (5) design the foam slug, (6) implement a field test, and (7) evaluate results.

  10. Reactivity to CO{sub 2} of chars prepared in O{sub 2}/N{sub 2} and O{sub 2}/CO{sub 2} mixtures for pulverized coal injection (PCI) in blast furnace in relation to char petrographic characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Pohlmann, Juliana G.; Osorio, Eduardo; Vilela, Antonio C.F. [Iron and Steelmaking Laboratory, UFRGS, Porto Alegre (Brazil); Borrego, Angeles G. [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2010-12-01

    Pulverized coal injection (PCI) is employed in blast furnace tuyeres in order to increase the injection rate without increasing the amount of unburned char inside the stack. When coal is injected with air in the region of tuyeres, the resolidified char will burn in an atmosphere with progressively lower oxygen content and higher CO{sub 2} concentration. In this study, an experimental approach comprising refiring has been followed to separate the combustion process into two distinct devolatilization and combustion steps. A drop tube furnace (DTF) operating at 1300 C in an atmosphere with low oxygen concentration was used to simulate devolatilization and then the char was refired into DTF at the same temperature under two different atmospheres O{sub 2}/N{sub 2} (typical combustion) and O{sub 2}/CO{sub 2} (oxy-combustion) with the same oxygen concentration. Coal injection was also performed under a higher oxygen concentration in both typical combustion and oxy-combustion atmospheres. The fuels tested comprised a petroleum coke and coals ranging in rank from high to low volatile bituminous, currently used for PCI injection. Specific surface areas, reactivity to CO{sub 2} and char petrography have been used to chars characterization. The morphology and appearance of the chars generated under oxy-fuel (O{sub 2}/CO{sub 2}) and conventional combustion (O{sub 2}/N{sub 2}) conditions with similar amount of oxygen were similar for each parent coal. Vitrinite-rich particles generated cenospheres with anisotropic optical texture increasing in size with increasing coal rank, whereas inertinite yielded a variety of morphologies and optical textures. The apparent reactivity to CO{sub 2} measured at high temperature (1000 C) tended to increase with burnout reflecting the operation under a regime controlled by internal diffusion in which surface area also increased. This may have a significant effect in the reactivity to CO{sub 2} of the chars inside the stack of the blast furnace

  11. Synthesis and characterization of the NiAl{sub 2}O{sub 4}, CoAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} spinels by the polymeric precursors method

    Energy Technology Data Exchange (ETDEWEB)

    Gama, L., E-mail: lucianna@dema.ufcg.edu.b [Federal University of Campina Grande, Department of Engineering of Materials, Av. Aprigio Veloso 882, 58.109-970 Campina Grande, PB (Brazil); Ribeiro, M.A. [Federal University of Campina Grande, Department of Engineering of Materials, Av. Aprigio Veloso 882, 58.109-970 Campina Grande, PB (Brazil); Barros, B.S. [Federal University of Rio Grande do Norte, Department of Chemistry, 59078-970 Natal, RN (Brazil); Kiminami, R.H.A. [Federal University of Sao Carlos, Department of Materials Engineering, 13565-905 Sao Carlos, SP (Brazil); Weber, I.T. [Federal University of Pernambuco, Department of Fundamental Chemistry, 50670-901 Recife, PE (Brazil); Costa, A.C.F.M. [Federal University of Campina Grande, Department of Engineering of Materials, Av. Aprigio Veloso 882, 58.109-970 Campina Grande, PB (Brazil)

    2009-08-26

    The spinels constitute an important group of materials with great technological appeal, being able to be applied as pigments, refractory, catalysts and electronic ceramics. In this paper, we reported the preparation of nanocrystalline NiAl{sub 2}O{sub 4}, CoAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} phases by Pechini method. This method employs the dissolution of cations precursors in a citric acid aqueous solution. Due to the high chemical homogeneity, cation segregation during thermal decomposition is minimal. The resulting powders were characterized by XRD, N{sub 2} adsorption/desorption curves (BET curves) and SEM. The X-ray diffraction patterns show that the synthesis is efficient to produce single-phased NiAl{sub 2}O{sub 4}, CoAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} powders and the crystallite sizes were 12, 34 and 20 nm, respectively. The micrographs show the formation of soft agglomerates with irregular morphology constituted by the superposition of the quite fine particles.

  12. Dissociative relaxation of I/sub 2//sup +/, Br/sub 2//sup +/, and Cl/sub 2//sup +/

    Energy Technology Data Exchange (ETDEWEB)

    Leach, S.

    1988-09-22

    Laser photodissociation results on dihalogen cations by McLoughlin et al. (McLoughlin, R.G.; Morrison, J.F.; Smith D.L. Int J. Mass Spectrom. Ion Processes 1984, 58, 201) are examined in the light of coincidence studies on fluorescence and dissociative process in I/sub 2//sup +/, Br/sub 2//sup +/, and Cl/sub 2//sup +/ Tuckett, R.P.; Castellucci, E.; Bonneau, E.; Dujardin, G.; Leach, S. Chem. Phys. 1985, 92, 43; Castellucci, E.; Dujardin, G.; Leach, S.; Tuckett, R.P. Chem. Phys. Lett. 1985, 116, 125 and of information from recent MO calculations on halogen dications. Assignments of the initial and final states in the two sets of experiments are discussed. Further experimental and theoretical investigations are proposed.

  13. On the LiCo{sub 2/3}Ni{sub 1/6}Mn{sub 1/6}O{sub 2} positive electrode material

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, Abdelfattah [ECME, FST Marrakech, University Cadi Ayyad, BP549, Av. A. Khattabi, Marrakech (Morocco); Saadoune, Ismael, E-mail: saadoune1@yahoo.f [ECME, FST Marrakech, University Cadi Ayyad, BP549, Av. A. Khattabi, Marrakech (Morocco); Amarilla, Jose Manuel [Instituto de Ciencias de Materiales de Madrid, CSIC, c/Sor Juana Ines de la Cruz, 3, Cantoblanco, 28049 Madrid (Spain); Hakkou, Rachid [ECME, FST Marrakech, University Cadi Ayyad, BP549, Av. A. Khattabi, Marrakech (Morocco)

    2011-04-15

    Research highlights: LiCo{sub 2/3}Ni{sub 1/6}Mn{sub 1/6}O{sub 2} layered oxide, prepared by the combustion method, consists of particles with homogenous distribution. Rietveld refinement shows that the crystal structure of this cathode material presents no Li/Ni mixing. The best cycling performances were recorded when the upper cut off is fixed at 4.5 V corresponding to a solid solution domain. - Abstract: LiCo{sub 2/3}Ni{sub 1/6}Mn{sub 1/6}O{sub 2} layered oxide was synthesized by the combustion method that led to a crystalline phase with good homogeneity and low particles size. The structural properties of the prepared positive electrode material were investigated by performing XRD Rietveld refinement. Practically no Li/Ni mixing was detected evidencing that the studied compound adopts almost an ideal {alpha}-NaFeO{sub 2} type structure. The Li||LiCo{sub 2/3}Ni{sub 1/6}Mn{sub 1/6}O{sub 2} cell showed a discharge capacity of 199 mAh g{sup -1} when cycled in the 2.7-4.6 V potential range while the best cycling performances were recorded when the upper cut off is fixed at 4.5 V. Structural changes in Li{sub x}Co{sub 2/3}Ni{sub 1/6}Mn{sub 1/6}O{sub 2} with lithium electrochemical de-intercalation were studied using X-ray diffraction. This study clearly shows the existence of a solid solution domain in the 0.1 < x < 1.0 composition range while for x = 0.1, a new phase appears explaining the decrease of the electrochemical performance when the cell is cycled at high upper cut off voltage.

  14. Silver film on nanocrystalline TiO{sub 2} support: Photocatalytic and antimicrobial ability

    Energy Technology Data Exchange (ETDEWEB)

    Vukoje, Ivana D., E-mail: ivanav@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Tomašević-Ilić, Tijana D., E-mail: tommashev@gmail.com [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Zarubica, Aleksandra R., E-mail: zarubica2000@yahoo.com [Department of Chemistry, Faculty of Science and Mathematics, University of Niš, Višegradska 33, 18000 Niš (Serbia); Dimitrijević, Suzana, E-mail: suzana@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade (Serbia); Budimir, Milica D., E-mail: mickbudimir@gmail.com [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Vranješ, Mila R., E-mail: mila@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Šaponjić, Zoran V., E-mail: saponjic@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Nedeljković, Jovan M., E-mail: jovned@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia)

    2014-12-15

    Highlights: • Simple photocatalytic rout for deposition of Ag on nanocrystalline TiO{sub 2} films. • High antibactericidal efficiency of deposited Ag on TiO{sub 2} support. • Improved photocatalytic performance of TiO{sub 2} films in the presence of deposited Ag. - Abstract: Nanocrystalline TiO{sub 2} films were prepared on glass slides by the dip coating technique using colloidal solutions consisting of 4.5 nm particles as a precursor. Photoirradiation of nanocrystalline TiO{sub 2} film modified with alanine that covalently binds to the surface of TiO{sub 2} and at the same time chelate silver ions induced formation of metallic silver film. Optical and morphological properties of thin silver films on nanocrystalline TiO{sub 2} support were studied by absorption spectroscopy and atomic force microscopy. Improvement of photocatalytic performance of nanocrystalline TiO{sub 2} films after deposition of silver was observed in degradation reaction of crystal violet. Antimicrobial ability of deposited silver films on nanocrystalline TiO{sub 2} support was tested in dark as a function of time against Escherichia coli, Staphylococcus aureus, and Candida albicans. The silver films ensured maximum cells reduction of both bacteria, while the fungi reduction reached satisfactory 98.45% after 24 h of contact.

  15. Synthesis and characterization of Gd{sub 2}O{sub 3} doped UO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Soldati, A.L., E-mail: asoldati@cab.cnea.gov.ar [Centro Atómico Bariloche (CAB) – Comisión Nacional de Energía Atómica (CNEA), Av. Bustillo 9500, CP: 8400 Bariloche (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. De los Pioneros 2300, CP: 8400 Bariloche (Argentina); Gana Watkins, I. [Centro Atómico Bariloche (CAB) – Comisión Nacional de Energía Atómica (CNEA), Av. Bustillo 9500, CP: 8400 Bariloche (Argentina); Fernández Zuvich, A. [Centro Atómico Bariloche (CAB) – Comisión Nacional de Energía Atómica (CNEA), Av. Bustillo 9500, CP: 8400 Bariloche (Argentina); Instituto Balseiro, Universidad Nacional de Cuyo, Av. Bustillo 9500, CP: 8400 Bariloche (Argentina); Napolitano, F.; Troiani, H. [Centro Atómico Bariloche (CAB) – Comisión Nacional de Energía Atómica (CNEA), Av. Bustillo 9500, CP: 8400 Bariloche (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. De los Pioneros 2300, CP: 8400 Bariloche (Argentina); and others

    2016-10-15

    UO{sub 2} nanoparticles doped with 4, 8, 10 and 15 wt% Gd{sub 2}O{sub 3}were synthesized by a reverse strike method. Crystal structure and chemical homogeneity were evaluated using a combination of X-ray diffraction and microscopy tools. An exhaustive study of the composition and its homogeneity at the micro and at the nanometer level was carried out in this nuclear fuel material. Field Emission Gun Scanning and Transmission Electron Microscopy images revealed the presence of micrometer scale agglomerates of nanoparticles, with rounded morphology and an average crystallite size of 100 nm. Rietveld refinements of high-statistic X-ray Diffraction data determined the crystal structure and composition. Furthermore, Energy Dispersive Spectroscopy using a 2 nm{sup 2} spot on the sample surface determined a Gd concentration variation around the average of ±5% in different spots of a single crystallite and of ±10% between different crystallites. However, when measuring large amounts of nanoparticles the concentration averages, producing a homogeneous composition distribution at the micrometer scale. - Highlights: • Synthesis of 4, 8, 10 and 15wt% Gd{sub 2}O{sub 3} doped UO{sub 2} nanoparticles. • Crystallite sizes around 100 nm and rounded morphology. • 90% Gd distribution homogeneity between particles for the less concentrated sample. • High Statistic X-ray Rietveld analysis determined an U{sub 1−x}Gd{sub x}O{sub 2−δ} fcc structure. • Phases with similar crystal structure and symmetry, but different lattice parameter.

  16. Pressure and field dependence of superconductivity in RbFe{sub 2}As{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Reiss, Pascal; Semeniuk, Konstantin; Brown, Philip; Grosche, F. Malte [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); Grube, Kai; Wolf, Thomas; Adelmann, Peter; Loehneysen, Hilbert von [Institut fuer Festkoerperphysik, Karlsruher Institut fuer Technologie, Karlsruhe (Germany)

    2015-07-01

    RbFe{sub 2}As{sub 2} is a member of the extensively investigated family of 122 iron based superconductors AFe{sub 2}As{sub 2}. It acts as the link between A=K and Cs, and as extremal hole-doping for A=Sr and Ba. The nature of the superconducting state in these compounds is still open, but likely to feature different nodal gap structures. We report resistivity measurements of very pure (RRR > 1000) crystals of RbFe{sub 2}As{sub 2}. Superconductivity at ambient pressure and zero field is observed below 2.8 K. We follow this transition and the upper critical field as a function of hydrostatic pressure up to 30 kbar. Furthermore we observe a non-Fermi liquid form for the temperature dependence of the resistivity in the normal state, which we track as a function of pressure and applied magnetic field.

  17. Particle Reduction Strategies - PAREST. Evaluation of emission reduction scenarios using chemical transport calculations. NO{sub 2}- and O{sub 3} reduction potentials of package of measures for further reduction of immissions in Germany; Strategien zur Verminderung der Feinstaubbelastung - PAREST. Bewertung von Emissionsminderungsszenarien mit Hilfe chemischer Transportberechnungen. NO{sub 2}- und O{sub 3}-Minderungspotenziale von Massnahmenpaketen zur weiteren Reduzierung der Immissionen in Deutschland. Teilbericht

    Energy Technology Data Exchange (ETDEWEB)

    Stern, Rainer [Freie Univ. Berlin (Germany). Inst. fuer Meteorologie, Troposphaerische Umweltforschung

    2013-06-15

    This report documents the effects of additional emission control measures the NO{sub 2}- and ozone-air quality in Germany (PM = particulate matter). The immission effects of the planned measures were calculated with the Chemistry-Aerosol-Transport Model REM CALGRID (RCG). [German] Dieser Bericht dokumentiert die Auswirkungen zusaetzlicher emissionsmindernder Massnahmen auf die NO{sub 2}- und die Ozon-Luftqualitaet in Deutschland. Die immissionsseitigen Auswirkungen der geplanten Massnahmen wurden auf der Basis von Berechnungen mit dem Chemie- Aerosol-Transportmodell REM-CALGRID (RCG) bestimmt. Grundlage der Szenarienrechnungen sind die im Rahmen des F and E-Vorhabens entwickelten Emissionsabschaetzungen, die die Aenderung der Emissionen aufgrund von technischen oder nicht-technischen Massnahmen beschreiben. Die den Berechnungen zugrunde liegende horizontale Aufloesung betraegt 0.125 Laenge und 0.0625 Breite oder circa 7 km x 8 km. Das meteorologische Referenzjahr ist 2005.

  18. Adsorption of CO{sub 2} from dry gases on MCM-41 silica at ambient temperature and high pressure. 2: Adsorption of CO{sub 2}/N{sub 2}, CO{sub 2}/CH{sub 4} and CO{sub 2}/H{sub 2} binary mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Youssef Belmabkhout; Abdelhamid Sayari [University of Ottawa, Ottawa, ON (Canada). Department of Chemistry

    2009-09-01

    Adsorption equilibrium capacity of CO{sub 2}, CH{sub 4}, N{sub 2}, H{sub 2} and O{sub 2} on periodic mesoporous MCM-41 silica was measured gravimetrically at room temperature and pressure up to 25 bar. The ideal adsorption solution theory (IAST) was validated and used for the prediction of CO{sub 2}/N{sub 2}, CO{sub 2}/CH{sub 4}, CO{sub 2}/H{sub 2} binary mixture adsorption equilibria on MCM-41 using single components adsorption data. In all cases, MCM-41 showed preferential CO{sub 2} adsorption in comparison to the other gases, in agreement with CO{sub 2}/N{sub 2}, CO{sub 2}/CH{sub 4}, CO{sub 2}/H{sub 2} selectivity determined using IAST. In comparison to well known benchmark CO{sub 2} adsorbents like activated carbons, zeolites and metal-organic frameworks (MOFs), MCM-41 showed good CO{sub 2} separation performances from CO{sub 2}/N{sub 2}, CO{sub 2}/CH{sub 4} and CO{sub 2}/H{sub 2} binary mixtures at high pressure, via pressure swing adsorption by utilizing a medium pressure desorption process (PSA-H/M). The working CO{sub 2} capacity of MCM-41 in the aforementioned binary mixtures using PSA-H/M is generally higher than 13X zeolite and comparable to different activated carbons.

  19. Thermoluminescent characteristics (TL) of K{sub 2}F{sub 5}: Y{sub 0.99} Tb{sub 0.01} irradiated with beta particles of {sup 90}Sr/{sup 90} Y; Caracteristicas termoluminiscentes (TL) de K{sub 2}F{sub 5}: Y{sub 0.99} Tb{sub 0.01} irradiado con particulas beta de {sup 90}Sr/{sup 90} Y

    Energy Technology Data Exchange (ETDEWEB)

    Baillet, C.; Azorin, J.; Rivera, T. [Dep. de Fisica, UAM-I, 09340 Mexico D.F. (Mexico)

    2005-07-01

    In this work the results of studying the thermoluminescent characteristics of the K{sub 2}F{sub 5}: Y{sub 0.99} Tb{sub 0.01} are presented. The material was characterized irradiating samples of K{sub 2}F{sub 5}: Y{sub 0.99}Tb{sub 0.01} in powder with beta radiation of {sup 90}Sr/{sup 90}Y. The studied characteristics were TL curve, response reproducibility, TL response in function of the dose and fading of the information. The samples exhibited a thermoluminescent curve (TL) with two very defined peaks centered respectively in 167 and 307 C. The TL response of the samples under the action of the beta radiation after 10 cycles (thermal erased, irradiation and reading of the samples) presented a standard deviation of 3.09%. The TL response of K{sub 2}F{sub 5}: Y{sub 0.99} Tb{sub 0.01} in function of the absorbed dose of beta radiation resulted lineal in the interval of 3 mGy to 1.29 Gy. The fading of the information contained in the samples of K{sub 2}F{sub 5}: Y{sub 0.99} Tb{sub 0.01} was of 40% in the first 10 minutes, which is due to the first peak. The obtained results suggest that the TL material resulted as promissory for its possible use as thermoluminescent dosemeter of beta radiation using the second peak of its TL curve like dosimetric peak. (Author)

  20. Synthesis and characterization of bimetallic Pd-Ni catalysts in a CeO{sub 2} matrix for the generation of H{sub 2} by the reforming reaction of methanol; Sintesis y caracterizacion de catalizadores bimetalicos Pd-Ni en una matriz de CeO{sub 2} para la generacion de H{sub 2} mediante la reaccion de reformado de metanol

    Energy Technology Data Exchange (ETDEWEB)

    Contreras C, R.

    2016-07-01

    The hydrothermal method was used for the synthesis of CeO{sub 2} nano rods using Ce(NO{sub 3}){sub 3}·6H{sub 2}O and NH{sub 4}OH. The catalytic support was calcined at 700 degrees Celsius. The synthesis of CeO{sub 2} nano rods were impregnated with an aqueous solution of Ni(NO{sub 3}){sub 2}·6H{sub 2}O by an incipient wetness impregnation method at an appropriate concentration to yield 5 and 15% of Ni in the catalysts. Then 0.5% of Pd was impregnated using PdCl{sub 2}. The samples obtained were calcined at 400 and reduced at 450 degrees Celsius. The catalytic materials were characterized by: temperature programmed reduction (TPR), Scanning Electron Microscopy (Sem) , surface area and X-ray diffraction (XRD) . Sem results showed that the CeO{sub 2} is formed by nano rods and in lesser proportion semi spherical particles. Bet surface area of the catalysts decreases with Ni loading onto the CeO{sub 2} nano rods. Pd O and Ni O were reduced at low and high temperature as was observed by TPR. The CeO{sub 2} one-dimensional nano rods showed a highly crystalline structure with sharp diffraction peaks, with a typical fluorite structure (cubic structure of the CeO{sub 2}) and characteristic peaks corresponding to metallic Ni. No diffraction peaks of Pd were found. This is due to the low concentration of this metal in the catalyst. These catalysts showed high activity and selectivity to H{sub 2} at maximum reaction temperature. According to the results of activity and selectivity, the catalysts with Pd-Ni are an alternative for the H{sub 2} production in auto thermal reforming reaction of methanol. (Author)

  1. Preparation of CdS@CeO{sub 2} core/shell composite for photocatalytic reduction of CO{sub 2} under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ijaz, Sana [CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190 (China); Institute of Chemical Sciences, Bahauddin Zakaryia University, Multan 60800 (Pakistan); Ehsan, Muhammad Fahad [CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190 (China); Ashiq, Muhammad Naeem, E-mail: naeemashiqqau@yahoo.com [Institute of Chemical Sciences, Bahauddin Zakaryia University, Multan 60800 (Pakistan); Karamat, Nazia [Institute of Chemical Sciences, Bahauddin Zakaryia University, Multan 60800 (Pakistan); He, Tao, E-mail: het@nanoctr.cn [CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2016-12-30

    Highlights: • CdS@CeO{sub 2}core(*)/shell composite is fabricated using a two-step method. • CdS@CeO{sub 2} can photoreduce CO{sub 2} into CH{sub 4} and CH{sub 3}OH under visible-light irradiation. • CdS@CeO{sub 2} can enhance photocatalytic activity due to increased charge separation. • Core shell strategy for photocatalyst preparation can improve photostability. - Abstract: Present work demonstrates fabrication of CdS@CeO{sub 2} core/shell composite and its application in the photocatalytic reduction of CO{sub 2} under visible-light irradiation (λ ≥ 420 nm). CdS@CeO{sub 2} composite has been successfully prepared by two-step chemical method, while CeO{sub 2} and CdS have been synthesized by one-step hydrothermal method. X-ray diffraction analysis confirms the formation of fluorite cubic structure of CeO{sub 2} and cubic phase of CdS. High resolution transmission electron microscopy and scanning electron microscopy reveal the microsphere morphology of CdS, while CeO{sub 2} (shell) is in the form of spherical particles that surround the CdS (core) in case of the composite. X-ray photoelectron spectroscopy has been used to confirm the composition, oxidation state of the elements and valance band of the obtained materials. The CdS@CeO{sub 2} core/shell composite and CdS can convert CO{sub 2} into methane and methanol under visible-light irradiation. The CdS@CeO{sub 2} composite shows higher yield for both methane and methanol than CdS due to low recombination rate of photogenerated electron/hole pairs, as well as a larger BET specific surface area. Moreover, the CdS@CeO{sub 2} core/shell composite also shows improved stability upon photocatalysis.

  2. Stability of Zn-Ni-TiO{sub 2} and Zn-TiO{sub 2} nanocomposite coatings in near-neutral sulphate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, A., E-mail: aboavida@fc.ul.pt; Almeida, I.; Frade, T. [CCMM, Departamento Quimica e Bioquimica da Faculdade de Ciencias da Universidade de Lisboa (Portugal); Tavares, A. C. [Institut National de la Recherche Scientifique-Energie Materiaux et Telecommunications (INRS-EMT) (Canada)

    2012-02-15

    Zn-Ni-TiO{sub 2} and Zn-TiO{sub 2} nanocomposites were prepared by galvanostatic cathodic square wave deposition. X-ray diffraction analysis and scanning electron microscopy revealed that the occlusion of TiO{sub 2} nanoparticles (spherical shaped with diameter between 19.5 and 24.2 nm) promotes the formation of the {gamma}-Ni{sub 5}Zn{sub 21} phase, changes the preferred crystallographic orientation of Zn from (101) and (102) planes to (002), and decreases the particle size of the metallic matrices. The stability of the nanocomposites immersed in near-neutral 0.05 mold m{sup -3} Na{sub 2}SO{sub 4} solution (pH 6.2) was investigated over 24 h. The initial open circuit potential for the Zn-Ni-TiO{sub 2} and Zn-TiO{sub 2} coatings were -1.32 and -1.51 V (vs. Hg/Hg{sub 2}SO{sub 4}), respectively, and changed to -1.10 and -1.49 V (vs. Hg/Hg{sub 2}SO{sub 4}) after 24 h of immersion. Data extracted from the steady state polarization curves demonstrated that the metal-TiO{sub 2} nanocomposites have, with respect to the metal coatings, a higher corrosion potential in the case of the Zn-Ni alloy composite; a lower corrosion potential in the case of Zn-based nanocomposite albeit the predominant (002) crystallographic orientation; and a lower initial corrosion resistance due to the smaller grain size and higher porosity in the Zn-Ni-TiO{sub 2} and Zn-TiO{sub 2} nanocomposites. Morphological and chemical analyses showed that a thicker passive layer is formed on the surface of the Zn-Ni-TiO{sub 2} and Zn-TiO{sub 2} deposits. After 24 h of immersion in the sulphate solution, the Zn-Ni-TiO{sub 2} coating has the highest corrosion stability due to the double-protective action created by the deposit's surface enrichment in Ni plus the higher amount of corrosion products.

  3. Propane combustion over Pt/Al{sub 2}O{sub 3} catalysts with different crystalline structures of alumina

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jung Eun; Kim, Bo Bae; Park, Eun Duck [Ajou University, Suwon (Korea, Republic of)

    2015-11-15

    The effects of the crystalline phases (α-Al{sub 2}O{sub 3}, κ-Al{sub 2}O{sub 3}, δ-Al{sub 2}O{sub 3}, θ-Al{sub 2}O{sub 3}, η-Al{sub 2}O{sub 3}, and γ-Al{sub 2}O{sub 3}) of the alumina support of Pt/Al{sub 2}O{sub 3} catalysts on the catalyst activity toward propane combustion were examined. The catalysts were characterized by N{sub 2} physisorption, CO chemisorption, temperature-programmed reduction (TPR), temperature programmed oxidation (TPO), transmission electron microscopy (TEM), and infrared spectroscopy (IR) after CO chemisorption. The Pt dispersion of the catalysts (surface Pt atoms/total Pt atoms), measured via CO chemisorption, was more dependent on the crystalline structure of alumina than on the surface area of alumina. The highest catalytic activity for propane combustion was achieved with Pt/α-Al{sub 2}O{sub 3}, which has the lowest Brunauer, Emmett, and Teller (BET) surface area and Pt dispersion. The lowest catalytic activity for propane combustion was exhibited by Pt/γ-Al{sub 2}O{sub 3}, which has the highest BET surface area and Pt dispersion. The catalytic activity was confirmed to increase with increasing Pt particle size in Pt/δ-Al{sub 2}O{sub 3}. The apparent activation energies for propane combustion over Pt/α-Al{sub 2}O{sub 3}, Pt/κ- Al{sub 2}O{sub 3}, Pt/δ-Al{sub 2}O{sub 3}, Pt/θ-Al{sub 2}O{sub 3}, Pt/η-Al{sub 2}O{sub 3}, and Pt/γ-Al{sub 2}O{sub 3} were determined to be 24.7, 21.4, 24.3, 22.1, 24.0, and 19.1 kcal/mol, respectively.

  4. Co-doping TiO{sub 2} with boron and/or yttrium elements: Effects on antimicrobial activity

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuzheng [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870 (China); Wu, Yusheng, E-mail: henanwys@sina.com [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870 (China); Yang, He; Xue, Xiangxin; Liu, Zhihua [Institute of Metallurgical Resources and Environmental Engineering, Northeastern University, Shenyang 110819 (China)

    2016-09-15

    Highlights: • B-Y/TiO{sub 2} nano materials firstly applied to the fields of antibacterial materials. • Systems analysis the existence state of boron and yttrium ion in TiO{sub 2}. • Doping B and Y greatly strengthened the antibacterial activity of TiO{sub 2}. - Abstract: Pure TiO{sub 2}, boron and/or yttrium doped TiO{sub 2} nano-materials were synthesized by a sol–gel method and characterized by XRD, SEM, XPS and PL. XRD analysis indicates that, in the pure TiO{sub 2} and B single doped TiO{sub 2} (B-TiO{sub 2}) nano-materials calcinated at 700 °C, the presence of TiO{sub 2} is a mixture of anatase and rutile; in the Y single doped (Y-TiO{sub 2}), B and Y co-doped TiO{sub 2} nano-materials (B/Y-TiO{sub 2}), the presence of TiO{sub 2} is anatase. SEM image shows the prepared materials have a common round morphology and hexagonal plate morphology caused by the agglomeration of particles. Boron atoms are partially embedded into the TiO{sub 2} interstitial structure or incorporated into the TiO{sub 2} lattice through occupying the position of the oxygen atoms. The results of antimicrobial experiment show that B/Y-TiO{sub 2} material has a remarkable antimicrobial activity. Compared with the visible light irradiation, antimicrobial activity of B/Y-TiO{sub 2} in dark is significant poor.

  5. Ni/TiO<sub>2 composite electrocoatings

    Directory of Open Access Journals (Sweden)

    Kollia, C.

    2005-12-01

    Full Text Available Nickel composite coatings have been studied in order to provide increased properties on engineering materials surfaces, such as higher electrical conductivity, wear and corrosion resistance and to decrease the end product manufacturing cost by plating on cheap materials. Adding TiO<sub>2 particles in the bath during the deposition process produced composite coatings. This was tried on electrodeposition from a Watts bath by conventional DC conditions and by pulse plating. The surfaces were studied by SEM, by profilometry and by Vickers microhardness, and its structure by X-ray diffraction. The incorporation percentage of TiO<sub>2 particles in the metallic matrix was estimated by EDS analysis. Corrosion measurements of the deposits were taken by Tafel curves. The results obtained show that particle incorporation percentage is higher for the Ni/TiO<sub>2 electrodeposits produced by pulse current and the microhardness is significantly increased compared to the electrodeposits produced by DC.

    Los electrodepósitos compuestos de níquel confieren mejores propiedades a la superficies de los materiales utilizados en ingeniería, tales como conductividad eléctrica, desgaste y resistencia a la corrosión, y disminuyen el costo del producto manufacturado al utilizarse como recubrimiento de acabado sobre materiales base más económicos. La adición de partículas de TiO<sub>2 al baño durante la electrodeposicion da lugar a la formación de recubrimientos compuestos. La electrodeposicion se llevó cabo en un baño Watts en condiciones convencionales de corriente continua y por electrodepósito pulsante. Las superficies fueron estudiadas por SEM y microanálisis EDS; se midió su microrrugosidad y microdureza Vickers; y su estructura se analizó mediante Difracción de Rayos X. Las medidas de corrosión de los depósitos se realizaron a partir del trazado de curvas de Tafel. Los resultados muestran que el porcentaje de

  6. Viscosity and diffusion of barium and fluoride in Na{sub 2}O/K{sub 2}O/Al{sub 2}O{sub 3}/SiO{sub 2}/BaF{sub 2} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Bocker, Christian, E-mail: christian.bocker@uni-jena.de [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany); Avramov, Isak [Institute of Physical Chemistry, Bulgarian Academy of Science, A.G. Bonchev Street, Building 11, 1113 Sofia (Bulgaria); Ruessel, Christian [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany)

    2010-04-21

    Graphical abstract: The interdiffusion coefficients of barium and fluoride and the viscosity of glasses as a function of temperature and BaF{sub 2}-concentration in the system Na{sub 2}O/K{sub 2}O/Al{sub 2}O{sub 3}/SiO{sub 2}/BaF{sub 2} were studied. - Abstract: The interdiffusion coefficients of barium and fluoride in glasses, in the system Na{sub 2}O/K{sub 2}O/Al{sub 2}O{sub 3}/SiO{sub 2} with BaF{sub 2} additions, were determined from the diffusion profiles using energy dispersive X-ray analysis in a scanning electron microscope. The diffusivities were in agreement with Arrhenius-equation. Diffusion coefficients of fluoride were in the range from 4.5 x 10{sup -15} m{sup 2} s{sup -1} to 30 x 10{sup -15} m{sup 2} s{sup -1} at 580 and 640 deg. C, respectively, while those of barium were 0.035 x 10{sup -15} m{sup 2} s{sup -1} at 600 and 1.3 x 10{sup -15} m{sup 2} s{sup -1} at 680 deg. C and hence are around two orders of magnitude smaller than the values for of fluoride. During the diffusion of F{sup -}, the charge compensation is assumed to be predominantly achieved by the simultaneous diffusion of highly mobile alkali ions. The viscosity of the melts decreased with increasing BaF{sub 2}-concentration. The diffusion coefficients did not obey Stokes-Einstein Law. In the case of the crystallization of BaF{sub 2} from silicate glasses, the rate determining step should be the diffusion of barium.

  7. Physical chemistry of the H[sub 2]SO[sub 4]/HNO[sub 3]/H[sub 2]O system: Implications for polar stratospheric clouds

    Energy Technology Data Exchange (ETDEWEB)

    Molina, M.J.; Zhang, R.; Wooldridge, P.J.; McMahon, J.R.; Kim, J.E.; Chang, H.Y.; Beyer, K.D. (Massachusetts of Technology, Cambridge, MA (United States))

    1993-09-10

    Polar stratospheric clouds (PSCs) play a key role in stratospheric ozone depletion. Surface-catalyzed reactions on PSC particles generate chlorine compounds that photolyze readily to yield chlorine radicals, which in turn destroy ozone very efficiently. The most prevalent PSCs form at temperatures several degrees above the ice frost point and are believed to consist of HNO[sub 3] hydrates; however, their formation mechanism is unclear. Results of laboratory experiments are presented which indicate that the background stratospheric H[sub 2]SO[sub 4]/H[sub 2]O aerosols provide an essential link in this mechanism: These liquid aerosols absorb significant amounts of HNO[sub 3] vapor, leading most likely to the crystallization of nitric acid trihydrate (NAT). The frozen particles then grow to form PSCs by condensation of additional amounts of HNO[sub 3] and H[sub 2]O vapor. Furthermore, reaction probability measurements reveal that the chlorine radical precursors are formed readily at polar stratospheric temperatures not just on NAT and ice crystals, but also on liquid H[sub 2]SO[sub 4] solutions and on solid H[sub 2]SO[sub 4] hydrates. These results imply that the chlorine activation efficiency of the aerosol particles increases rapidly as the temperature approaches the ice frost point regardless of the phase or composition of the particles.

  8. Aspects on sintering and grain growth in pure and Al{sub 2}O{sub 3}-SiO{sub 2} doped UO{sub 2} pellets

    Energy Technology Data Exchange (ETDEWEB)

    Assis, Gino de; Ferraz, Wilmar Barbosa [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Nucleo de Tecnologia do Combustivel], e-mail: assisg@cdtn.br, e-mail: ferrazw@cdtn.br; Tambourgi, Elias Basile [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Quimica], e-mail: eliastam@feq.unicamp.br

    2009-07-01

    The sintering behavior of UO{sub 2} pellets was investigated at 1700 deg C/2h/H{sub 2} and 1750 deg C/4h/H{sub 2}, using fresh and storage UO{sub 2} powders. Moreover, the sintering behavior of Al{sub 2}O{sub 3}-SiO{sub 2} doped UO{sub 2} pellets obtained from storage powder, in the same sintering conditions was also investigated. Pellets obtained from fresh UO{sub 2} powder have presented heterogeneous grain microstructures as they were sintered at 1700 deg C/2h/H{sub 2} and homogeneous grain microstructures when they were sintered at 1750 deg C/4h/H{sub 2}. On the contrary, pellets obtained from storage powder have presented homogeneous grain microstructures when they were sintered at 1700 deg C/2h/H{sub 2} and heterogeneous grain microstructures when they were sintered at 1750 deg C/4h/H{sub 2}.On the other hand, the pellets with additions of Al{sub 2}O{sub 3}-SiO{sub 2} presented homogeneous grain microstructures, regardless the sintering conditions were. The mechanisms by which the homogeneous and the heterogeneous grain microstructures were developed will be discussed in this paper concerning the fresh powder, the storage powder, the sintering conditions and the Al{sub 2}O{sub 3}-SiO{sub 2} additions. (author)

  9. Electronic structures of ReS sub 2 , ReSe sub 2 and TcS sub 2 in the real and the hypothetical undistorted structures

    CERN Document Server

    Fang, C M; Haas, C; Groot, R A D

    1997-01-01

    The transition-metal dichalcogenides ReX sub 2 (X = S or Se) and TcS sub 2 with a d sup 3 electron configuration have distorted CdCl sub 2 and Cd(OH) sub 2 structures, respectively, with the Re(Tc) atoms in each layer forming parallelogram-shaped connected clusters (diamond chain). Ab-initio band-structure calculations were performed for ReX sub 2 and TcS sub 2 , and the hypothetical undistorted 1T-TcS sub 2 and 3R-ReX sub 2 structures. The calculations show that ReS sub 2 , ReSe sub 2 and TcS sub 2 are semiconductors with energy gaps of about 1.0 eV, 0.5 eV and 0.7 eV, respectively, while for the undistorted structures the Fermi level is in the partly filled band of d sub x sub sup 2 sub - sub y sub sup 2 and d sub x sub y orbitals of the t sub 2 sub g manifold. X-ray photoemission spectra for the core levels and valence band of ReSe sub 2 and ReS sub 2 are presented. The valence x-ray photoemission spectra showed that ReS sub 2 is a p-type semiconductor with an energy gap of about 1.5 eV, while ReSe sub 2 i...

  10. Effect of interfacial interactions on the initial growth of Cu on clean SiO sub 2 and 3-mercaptopropyltrimethoxysilane-modified SiO sub 2 substrates

    CERN Document Server

    Hu Ming Hui; Tsuji, Y; Okubo, T; Yamaguchi, Y; Komiyama, H

    2002-01-01

    The effect of interfacial interactions on the initial growth of Cu on clean SiO sub 2 and 3-mercaptopropyltrimethoxysilane (MPTMS)-modified SiO sub 2 substrates by sputter deposition was studied using transmission electron microscopy, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. Plasma damage during sputter deposition makes surfaces of MPTMS-modified SiO sub 2 substrates consist of small MPTMS islands several tens of nanometers in diameter and bare SiO sub 2 areas. These MPTMS islands are composed of disordered multilayer MPTMS aggregates. The initial growth behavior of Cu on MPTMS-modified SiO sub 2 substrates differs from that on clean SiO sub 2 substrates, although Cu grows in three-dimensional-island mode on both of them. After a 2.5-monolayer Cu deposition on clean SiO sub 2 substrates, spherical Cu particles were formed at a low number density of 1.3x10 sup 1 sup 6 /m sup 2 and at a long interparticle distance of 5 nm. In contrast, after the same amount of deposition on MP...

  11. The reduction of I{sub 2} by H{sub 2}O{sub 2} in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Ball, J.M.; Hnatiw, J.B. [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.; Sims, H.E. [AEA Technology, Harwell Laboratory, Didcot (United Kingdom)

    1996-12-01

    The reduction of iodine by hydrogen peroxide is an important process which leads to a lower amount of molecular iodine in irradiated solutions of iodide as the pH is increased. There is quite a large amount of information on the reaction now but no consensus in the literature on the mechanisms for reaction and the generally accepted mechanism does not appear to be correct. A number of studies of the kinetics of the reaction in the pH range 2-7 have been carried out where the iodine reduction process exhibited a 1/[H{sup +}]{sup 2} dependence consistent with the proposed mechanism which were attributed primarily to the reaction of H{sub 2}O{sub 2} with IO{sup -}. Deviations were observed in the pH range 6-7 and were explained by incorporating the reaction of I{sub 2}OH{sup -} with H{sub 2}O{sub 2}. In some other experiments it was suggested that the failure to maintain a 1/[H{sup +}]{sup 2} dependence at high pH was due to the iodine hydrolysis being rate determining. Data from an experimental program performed at AECL described in this paper confirms that the 1/[H{sup +}]{sup 2} dependence does not hold at high pH. These studies were carried out as a function of acid, iodide, peroxide and buffer concentration for three buffers, barbital, citrate and phosphate. This paper discuss two mechanisms which involve the formation of an HOOI intermediate in the rate determining step and which adequately describe the experimental data. (author) 4 figs., 2 tabs., 23 refs.

  12. Mechanism of enhanced photocatalysis of TiO{sub 2} by Fe{sup 3+} in suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Junwei [Department of Municipal Engineering, School of Civil Engineering, Southeast University, Southeast University, Nanjing 210096 (China); School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China); Fu Dafang, E-mail: fdf@seu.edu.cn [Department of Municipal Engineering, School of Civil Engineering, Southeast University, Southeast University, Nanjing 210096 (China); Gao Haiying; Deng Lin [Department of Municipal Engineering, School of Civil Engineering, Southeast University, Southeast University, Nanjing 210096 (China)

    2011-12-01

    In this work, the mechanism of enhanced photocatalysis of TiO{sub 2} with Fe{sup 3+} was studied using Sulfadiazine (SD) as the model compound. Results indicated that degradation rate of SD was enhanced by the addition of Fe{sup 3+} in TiO{sub 2} suspension. The crystalline structure of TiO{sub 2} particles was stable in suspensions. The hydroxyl radical generated by TiO{sub 2}/Fe{sup 3+} (both TiO{sub 2} and Fe{sup 3+}) photocatalysis was in a higher yield. Moreover, Fe{sup 2+} was found not to give an obvious impact on the SD degradation in TiO{sub 2} suspension, whereas Fe{sup 3+} had a notable effect. The adsorption amount of TiO{sub 2} was greatly enhanced by the addition of Fe{sup 3+} in suspensions. Finally, an interaction model of SD degradation in TiO{sub 2} suspension containing Fe{sup 3+} was also proposed by investigating of surface behaviors of TiO{sub 2} particles. It will be beneficial to use Fe{sup 3+} as the electron acceptors on the surface of TiO{sub 2} particles, which helps to improve the yield of hydroxyl radical.

  13. Growth of single phase Bi sub 2 Sr sub 2 CaCu sub 2 O sub x whiskers using optimized starting compositions for glassy precursors

    CERN Document Server

    Sugimata, E; Kume, E; Sakai, S

    2003-01-01

    Single phase Bi sub 2 Sr sub 2 CaCu sub 2 O sub x whiskers were grown by optimized starting compositions for glassy precursors. The most optimal starting composition ratio and the composition after the whisker growth were found to be Bi : Sr : Ca : Al = 0.96 : 1.10 : 0.37 : 1.21 : 0.61 and Bi sub 2 sub . sub 2 sub 5 Sr sub 2 sub . sub 0 sub 9 Ca sub 0 sub . sub 8 sub 7 Cu sub 2 sub . sub 0 sub 0 O sub x , respectively. From the results of R-T characteristics, it was determined that there was no intergrowth of the Bi sub 2 Sr sub 2 Ca sub 2 Cu sub 3 O sub x phase. (author)

  14. Structural and morphological characterization of TiO{sub 2}-ZrO{sub 2} powders obtained by the polymeric precursors method; Caracterizacao estrutural e morfologica de pos de TiO{sub 2}-ZrO{sub 2} obtidos pelo metodo dos precursores polimericos

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, M.A.; Gama, L.; Bispo, A.; Neiva, L.S., E-mail: m_aparecidaribeiro@yahoo.com.b [Universidade Federal de Campina Grande (DEMa/UFCG), PB (Brazil). Dept. de Engenharia de Materiais; Bernardi, M.I.B. [Universidade de Sao Paulo (IFSC/USP), Sao Carlos, SP (Brazil). Inst. de Fisica; Kiminami, R.H.G.A. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    This work aims to characterize the structure and morphology of TiO{sub 2}-ZrO{sub 2} powders obtained by polymeric precursor method. For this we studied the following compositions: 0.25, 0.5 and 0.75 moles of Zr and calcined at 800 deg C for one hour. The powders obtained were characterized by XRD, SEM and nitrogen adsorption (BET). The analysis of X-ray diffraction showed that the powders had a phase of TiO{sub 2} in the anatase form and a tetragonal phase of ZrO{sub 2}. The crystallite size was between 8, 13 and 11 nm respectively. The analysis of scanning electron microscopy showed the growth of ZrO{sub 2} nanoparticles and that these comprise spherical agglomerates of less than 100 nm. Particle size determined by the BET ranging 28.1-29.5 nm, showing thereby the character of nanosized powders. (author)

  15. Synthesis, characterization and catalytic properties of nanocrystaline Y{sub 2}O{sub 3}-coated TiO{sub 2} in the ethanol dehydration reaction

    Energy Technology Data Exchange (ETDEWEB)

    Fajardo, Humberto Vieira [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Departamento de Quimica; Longo, Elson [Universidade Estadual Paulista (UNESP), Araraquara, SP (Brazil). Departamento de Fisico-Quimica; Leite, Edson Roberto; Libanori, Rafael [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica; Probst, Luiz Fernando Dias [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Departamento de Quimica; Carreno, Neftali Lenin Villarreal [Universidade Federal de Pelotas (UFPel), RS (Brazil). Departamento de Quimica Analitica e Inorganica

    2012-03-15

    In the present study, TiO{sub 2} nano powder was partially coated with Y{sub 2}O{sub 3} precursors generated by a sol-gel modified route. The system of nanocoated particles formed an ultra thin structure on the TiO{sub 2} surfaces. The modified nanoparticles were characterized by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) analysis, Zeta potential and surface area through N{sub 2} physisorption measurements. Bioethanol dehydration was used as a probe reaction to investigate the modifications on the nanoparticles surface. The process led to the obtainment of nanoparticles with important surface characteristics and catalytic behavior in the bioethanol dehydration reaction, with improved activity and particular selectivity in comparison to their non-coated analogs. The ethylene production was disfavored and selectivity toward acetaldehyde, hydrogen and ethane increased over modified nanoparticles. (author)

  16. Study on collisional deactivation of O{sub 2}({sup 1}{Delta}{sub g}) by H{sub 2} and D{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Du Shuyan [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Leng Jing, E-mail: ljjx@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Wang Junhui; Yang Heping; Sha Guohe; Zhang Cunhao [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2011-05-26

    Highlights: {yields} The deactivation rate constants of O{sub 2}({sup 1}{Delta}{sub g}) by H{sub 2} and D{sub 2} are measured. {yields} The figures agree well with the quantum mechanical calculation by Kustrev. {yields} The O{sub 2}({sup 1}{Delta}{sub g}) deactivation by H{sub 2}/D{sub 2} is analyzed by Schmidt's E-V energy transfer model. {yields} The main deactivation channels of O{sub 2}({sup 1}{Delta}{sub g}) for H{sub 2} and D{sub 2} are given respectively. - Abstract: The deactivation rate constants of O{sub 2}({sup 1}{Delta}{sub g}) by H{sub 2} and D{sub 2} are respectively measured to be 3.91 {+-} 0.12 x 10{sup -18} cm{sup 3} s{sup -1} and 1.1 {+-} 0.3 x 10{sup -19} cm{sup 3} s{sup -1}, which agree well with the quantum mechanical calculation by Kustrev. Their deactivation mechanisms by H{sub 2} and D{sub 2} are analyzed according to the E-V energy transfer model developed by Schmidt, indicating that the main deactivation channel for H{sub 2} is O{sub 2}({sup 1}{Delta}{sub g},v=0{yields}{sup 3}{Sigma}{sub g}{sup -},v{sup ''}=0) and H{sub 2} ({Delta}v = 2), while that for D{sub 2} is O{sub 2}({sup 1}{Delta}{sub g},v{sup '}=0{yields}{sup 3}{Sigma}{sub g}{sup -},v{sup ''}=1) and D{sub 2} ({Delta}v = 2), which entirely matches the calculation by Kustrev.

  17. The CO{sub 2} gasification kinetics of olive residue

    Energy Technology Data Exchange (ETDEWEB)

    Ollero, P.; Serrera, A.; Arjona, R.; Alcantarilla, S. [University of Seville (Spain). Chemical and Environmental Engineering Dept.

    2003-02-01

    Orujillo, sometimes called wood matter from pressed oil-stone (WPOS) is a residue from the olive oil mill industry. The generation of this biomass residue is concentrated in small areas allowing its use as fuel for medium size gasification and combustion plants. Rates of gasification of WPOS char were measured in a TGA at various temperatures (800-850-875-900-950{sup o}C), CO{sub 2} partial pressures (0.20-0.35-0.50 bar) and CO partial pressures (0.0-0.20 bar). The experiments were carried out with a monolayer bed of very fine particles well exposed to the gas so as to minimise mass and heat transfer resistances. Two kinetic models, the nth order model and Langmuir-Hinshelwood model, have been used to fit with the reactivity data. For pure CO{sub 2} experiments the kinetic parameters of nth order model were E=133 kJ/mol and n=0.43. The Langmuir-Hinshelwood kinetic model clearly describes the observed CO inhibition effect on the CO{sub 2} gasification.(author)

  18. Pressure induced magnetic ordering in SrCo{sub 2}P{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Rosner, Helge; Ackerbauer, Sarah; Bergmann, Christoph; Besser, Moritz; Nicklas, Michael; Geibel, Christoph [MPI CPfS, Dresden (Germany)

    2015-07-01

    Since the discovery of superconductivity in doped iron pnictides, in particular the AFe{sub 2}As{sub 2} systems of the ThCr{sub 2}Si{sub 2} structure type, the intricate interplay of crystal structure, magnetism and superconductivity in these compounds has attracted broad attention. It is widely believed that the superconductivity of this compound family is closely related tho spin fluctuations. SrCo{sub 2}P{sub 2} is a structural homologue of the AFe{sub 2}As{sub 2} compound series, exhibiting a paramagnetic ground state, but in close vicinity to a quantum critical point. In our joined experimental and theoretical study we demonstrate that under hydrostatic pressure the system undergoes an isostructural transition to the so-called tetragonal collapsed state with a strongly reduced c/a ratio by about 15%. Surprisingly, this transition is accompanied by magnetic ordering, indicated by a magnetic-field-dependent kink in the resistivity. Our results are supported by density functional electronic structure calculations.

  19. Specific heat of Ho sub 2 Co sub 17 and Er sub 2 Co sub 17

    Energy Technology Data Exchange (ETDEWEB)

    Franse, J.J.M.; Klaasse, J.C.P.; Sinnema, S. (Amsterdam Univ. (NL). Natuurkunding Lab.); Radwanski, R.J. (University of Mining and Metallurgy, Krakow (PL). Solid State Physics Dept.)

    1988-12-01

    The specific heat of polycrystalline samples of Ho{sub 2}Co{sub 17} and Er{sub 2}Co{sub 17} has been measured between 1.25 K and 38 K in zero field and in an applied field of 5 T. The electronic, lattice, nuclear and crystal field contributions to the specific heat have been separated.

  20. Superconductivity induced by oxygen doping in Y{sub 2}O{sub 2}Bi

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Xiyue; Deng, Shuiquan [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS), Fuzhou (China); Gordon, Elijah E. [Department of Chemistry, North Carolina State University, Raleigh, NC (United States); Whangbo, Myung-Hwan [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS), Fuzhou (China); Department of Chemistry, North Carolina State University, Raleigh, NC (United States)

    2017-08-14

    When doped with oxygen, the layered Y{sub 2}O{sub 2}Bi phase becomes a superconductor. This finding raises questions about the sites for doped oxygen, the mechanism of superconductivity, and practical guidelines for discovering new superconductors. We probed these questions in terms of first-principles calculations for undoped and O-doped Y{sub 2}O{sub 2}Bi. The preferred sites for doped O atoms are the centers of Bi{sub 4} squares in the Bi square net. Several Bi 6p x/y bands of Y{sub 2}O{sub 2}Bi are raised in energy by oxygen doping because the 2p x/y orbitals of the doped oxygen make antibonding possible with the 6p x/y orbitals of surrounding Bi atoms. Consequently, the condition necessary for the ''flat/steep'' band model for superconductivity is satisfied in O-doped Y{sub 2}O{sub 2}Bi. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Electrical transport properties of the unconventional superconductor YFe{sub 2}Ge{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Semeniuk, Konstantin; Chen, Jiasheng; Brown, Philip; Zou, Yang; Grosche, Malte [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); Feng, Zhuo [London Centre of Nanotechnology, University College London, London (United Kingdom); Lampronti, Giulio [Dept. of Earth Sciences, University of Cambridge, Cambridge (United Kingdom)

    2016-07-01

    YFe{sub 2}Ge{sub 2} is a paramagnetic d-electron system which stands out due to its high Sommerfeld ratio of its specific heat capacity of 100 mJ/(mol K{sup 2}) and non Fermi-liquid T{sup 3/2} power law temperature dependence of the electrical resistivity. The material was found to be superconducting below about 1.8 K. Advances in YFe{sub 2}Ge{sub 2} crystal growth allowed us to obtain high quality samples with residual resistivity ratios of the order of 200. Recent measurements of magnetisation and heat capacity provide further evidence for superconductivity, and the correlation between the transition temperature and the sample quality, the enhanced Sommerfeld coefficient and the anomalous T-dependence of the resistivity indicate that superconductivity in YFe{sub 2}Ge{sub 2} is unconventional. We report the results of detailed electrical resistivity measurements on YFe{sub 2}Ge{sub 2} as a function of temperature, magnetic field and hydrostatic pressure, which provide further insight into the nature of superconducting and normal states of the material.

  2. Rapid preparation of ultrafine BaSO{sub 3} by SO{sub 2} storage material

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fei; Sha, Feng; Qiao, Xian Shu; Zhao, Tian Xiang; Guo, Bo; Zhang, Jian Bin [College of Chemical Engineering, Inner Mongolia University of Technology, Huhhot (Korea, Republic of)

    2017-01-15

    In this work, a green and efficient process was developed for the preparation of ultrafine BaSO{sub 3} with layered nanostructure surface via the reaction of BaCl{sub 2} with a SO{sub 2} storage material (SO{sub 2}SM) at room temperature. The absorption of SO{sub 2} with equimolar ethylenediamine (EDA) and ethylene glycol (EG) afforded SO{sub 2}SM, which not only offered alkyl sulfite but also released EDA and EG that served as efficient surfactants to promote the formation of BaSO{sub 3} with spherical morphology and porous structure in the process of synthesis of ultrafine BaSO{sub 3}. The factors affecting the morphology and size of BaSO{sub 3} particle were assessed by investigating the effects of SO{sub 2}SM concentration, BaCl{sub 2} concentration, stirring time and speed. It was found that a higher SO{sub 2}SM concentration led to a higher degree of supersaturation, and the particle size of BaSO{sub 3} could be reduced by increasing SO{sub 2}SM concentration. Moreover, under the identified optimal reaction conditions, ultrafine BaSO{sub 3} was obtained with an average diameter of 450 nm. In addition, a plausible formation process of BaSO{sub 3} was proposed to explain the observed reaction results. Overall, the developed process in this work provides an efficient method for the capture, utilization, and conversion of SO{sub 2} into a valuable chemical.

  3. Modifications of structural and physical properties induced by swift heavy ions in Gd{sub 2}Ti{sub 2}O{sub 7} and Y{sub 2}Ti{sub 2}O{sub 7} pyrochlores

    Energy Technology Data Exchange (ETDEWEB)

    Sellami, N., E-mail: neila.sellami@u-psud.fr [Univ. Paris Sud, ICMMO-LEMHE, Bât. 410, F-91405 Orsay (France); Sattonnay, G. [Univ. Paris Sud, ICMMO-LEMHE, Bât. 410, F-91405 Orsay (France); Grygiel, C.; Monnet, I. [CIMAP, CEA, CNRS, Université de Caen, BP 5133, F-14070 Caen Cedex 5 (France); Debelle, A. [CSNSM, CNRS, IN2P3, Université Paris-Sud, Bât. 108, F- 91405 Orsay (France); Legros, C. [Univ. Paris Sud, ICMMO-LEMHE, Bât. 410, F-91405 Orsay (France); Menut, D. [CEA, DEN, Service de Recherches Métallurgiques Appliquées, 91191 Gif-Sur-Yvette (France); Miro, S. [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Simon, P. [CNRS UPR 3079 CEMHTI, 1D avenue de la Recherche Scientifique, F-45071 Orléans Cedex 2 (France); Bechade, J.L [CEA, DEN, Service de Recherches Métallurgiques Appliquées, 91191 Gif-Sur-Yvette (France); Thomé, L. [CSNSM, CNRS, IN2P3, Université Paris-Sud, Bât. 108, F- 91405 Orsay (France)

    2015-12-15

    The structural transformations induced by ionization processes in Gd{sub 2}Ti{sub 2}O{sub 7} and Y{sub 2}Ti{sub 2}O{sub 7} pyrochlores irradiated with swift heavy ions have been studied using XRD and Raman experiments. Results show that irradiation induces amorphization and that the phase transformation build-up can be accounted for in the framework of a model involving a single-impact mechanism. The radiation induced amorphization build-up is faster in Gd{sub 2}Ti{sub 2}O{sub 7} than in Y{sub 2}Ti{sub 2}O{sub 7}. Moreover, a decrease of the thermal conductivity (measured by the laser flash method) is induced by irradiation both in Gd{sub 2}Ti{sub 2}O{sub 7} and Y{sub 2}Ti{sub 2}O{sub 7}.

  4. PCLI{sub 2}/Ca(OH){sub 2} bioactive composite for endodontic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Kleberde Arruda [Departamento de Fisica e Quimica, Instituto de Ciencias Exatas, Universidade Federal de Itajuba-UNIFEI, Av. BPS 1303, 37500-903, Itajuba/MG (Brazil); Caniello, Thylander Magno [Departamento de Fisica e Quimica, Instituto de Ciencias Exatas, Universidade Federal de Itajuba-UNIFEI, Av. BPS 1303, 37500-903, Itajuba/MG (Brazil); Alencar de Queiroz, Alvaro Antonio [Departamento de Fisica e Quimica, Instituto de Ciencias Exatas, Universidade Federal de Itajuba-UNIFEI, Av. BPS 1303, 37500-903, Itajuba/MG (Brazil)

    2004-11-01

    The use of biodegradable macroporous polymer-ceramic composites in treating bone defects has become widely used in clinical practice. In this work, the synthesis and characterization of the composite poly({epsilon}-caprolactone)-iodine/calcium hydroxide (PCLI{sub 2}/Ca(OH){sub 2}), developed for endodontic therapy are presented. The composite was obtained by the ring opening of the {epsilon}-caprolactone monomer using iodine (I{sub 2}) as catalyst. The microstructural analysis by scanning electron microscopy (SEM) indicates that the composite PCLI{sub 2}/Ca(OH){sub 2} has a macroporous sponge-like structure. The biodegradable composite showed excellent antimicrobial activities against Escherichia coli and Staphylococcus aureus. The X-ray radiography of the implanted composite revealed a good adhesion in the root canal and excellent radiopacity.

  5. Chamber wall interactions with HBr/Cl{sub 2}/O{sub 2} plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Ashutosh K.; Ohashi, Tomohiro; Donnelly, Vincent M., E-mail: vmdonnelly@uh.edu [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004 (United States)

    2015-07-15

    The authors have studied the interaction of HBr/Cl{sub 2}/O{sub 2} inductively coupled plasmas with reactor chamber wall deposits, with and without Si etching, using the “spinning wall” technique. The spinning wall is part of the reactor chamber walls, allowing near-real-time analysis of the composition of surface layers via Auger electron spectrometry and determination of species desorbing off the walls by mass spectrometry. In HBr plasmas with no bias voltage on the Si substrate, and hence no Si etching, HBr is ∼30% dissociated, and H{sub 2} and Br{sub 2} form in the plasma. Layers deposited on the reactor chamber contained little if any Br under these conditions. Adding O{sub 2} to an HBr plasma leads to formation of H{sub 2}O and increased Br{sub 2} (compared to a pure HBr plasma) products that desorb from the spinning wall. H{sub 2}O has a very long residence time on the surface. With bias voltage applied to the Si substrate in an HBr plasma, mass spectrometer signals are prominent for SiBr and SiBr{sub 3}, and weaker for SiBr{sub 2}, SiBr{sub 4}, Si{sub 2}Br{sub 4}, Si{sub 2}Br{sub 5}, and Si{sub 2}OBr{sub 5}. Under these conditions, a SiO{sub x}Br{sub y} layer deposits on the spinning wall. Adding 20% O{sub 2} to HBr stops etching and eliminates Br from the surface layer, indicating that Br on the reactor walls is a result of SiBr{sub x} impingement and not from bromination by impinging Br. With HBr/Cl{sub 2} plasmas and no bias on the stage, a SiO{sub x}Cl{sub y} layer deposits, and no Br is detected. HCl, BrCl, and Br{sub 2} were detected in the line-of-sight leak, around the spinning wall, of a HBr/Cl{sub 2} (1:1) gas mixture in the absence of a plasma. Residence time analysis of species in the chamber and a change in the product distribution with a change in the composition of the layer deposited on the chamber wall suggest that reactions forming these products in the absence of a plasma occur on the reactor walls. With a plasma and bias on the Si

  6. CO{sub 2} HYDROGENATION TO METHANOL ON Cu-ZrO{sub 2} CATALYSTS

    Energy Technology Data Exchange (ETDEWEB)

    F. Bali [Laboratoire de Chimie du Gaz Naturel, Faculte de Chimie. Universite H. Boumediene, Algiers (Algeria); L.Jalowiecki- Duhamel [Unite de Catalyse et Chimie du Solide, Lille (France)

    2008-09-30

    The effective utilization of CO{sub 2} has been catching great attention due to its environmental relevance. In addition, synthesis of methanol from CO{sub 2}+H{sub 2} is one of most economic processes. Therefore, it is important to develop new catalysts with a high activity and selectivity to methanol. In the present study, we report on CO{sub 2} hydrogenation activity and selectivity of zirconium-copper oxides. The characterization of the catalysts in the oxidized and partially reduced state (after treatment in H{sub 2}) using in-situ techniques such as XRD and chemical catalytic hydrogen storage titration, allows proposing a mechanistic model for the formation of methanol and methane related to specific catalytic active sites.

  7. Electro-synthesis, characterization and photoconducting performance of ITO/polybithiophene–MnO{sub 2} composite

    Energy Technology Data Exchange (ETDEWEB)

    Zouaoui, H.; Abdi, D. [Laboratoire d’Energétique et d’Electrochimie du Solide, Université Ferhat Abbas Sétif-1, Sétif 19000 (Algeria); Bahloul, A.; Nessark, B. [Laboratoire d’Electrochimie et Matériaux, Université Ferhat Abbas Sétif-1, Sétif 19000 (Algeria); Briot, E.; Groult, H. [Sorbonne Universités, Université Paris 6 (UPMC), Physicochimie des Electrolytes et Nanosystèmes Interfaciaux (PHENIX), 4 place Jussieu, 75252 Paris Cedex 05 (France); Mauger, A. [Sorbonne Universités, Université Paris 6 (UPMC), Institut de Minéralogie et de Physique des Milieux Condensés (IMPMC), 4 place Jussieu, 75252 Paris Cedex 05 (France); Julien, C.M., E-mail: christian.julien@upmc.fr [Sorbonne Universités, Université Paris 6 (UPMC), Physicochimie des Electrolytes et Nanosystèmes Interfaciaux (PHENIX), 4 place Jussieu, 75252 Paris Cedex 05 (France)

    2016-06-15

    Highlights: • PBTh–MnO{sub 2} composites are prepared by electro-polymerization of bithiophene on ITO. • Photocurrent of ITO/PBTh–MnO{sub 2} films is three times higher than that of ITO/PBTh substrate. • Electrochemical gap, HOMO and LUMO potentials are determined. • ITO/PBTh–MnO{sub 2} films can be used as a new active material in solar cells. - Abstract: Manganese dioxide is synthesized by reduction reaction of potassium permanganate with hydrogen peroxide. The as-synthesized α-MnO{sub 2} is characterized by powder X-ray diffraction and infrared spectroscopy. The MnO{sub 2} particles are used to prepare composite films containing polybithophene (PBTh) on indium tin oxide (ITO) glass substrates. The composite films ITO/PBTh–MnO{sub 2} are obtained by electro-polymerization of bithiophene in the presence the α-MnO{sub 2} particles dispersed in the electrolytic solution. The XRD and SEM analyses show that the α-MnO{sub 2} particles of size in the range 100–300 nm are incorporated in the polymer. The films are characterized by cyclic voltammetry impedance spectroscopy, UV–vis spectroscopy and scanning electron microscopy. As a result, the electrochemical gap and the optical gap are shifted by the incorporation of MnO{sub 2} from 2.15 eV for ITO/PBTh to 1.88 eV for ITO/PBTh–MnO{sub 2}, while the electrical conductivity decreases from 195.35 S/cm for ITO/PBTh down to 0.047 S/cm for ITO/PBTh–MnO{sub 2} at the highest MnO{sub 2} investigated. The photo-electrochemical measurements also indicate that the ITO/PBTh–MnO{sub 2} films show a photocurrent that is three times higher than that of ITO/PBTh substrate to reach 20.6 μA cm{sup −2}, so that such a composite can be used as a new active material in solar cells.

  8. On the mechanism of nanoparticulate CeO{sub 2} toxicity to freshwater algae

    Energy Technology Data Exchange (ETDEWEB)

    Angel, Brad M., E-mail: Brad.Angel@csiro.au [Centre for Environmental Contaminants Research, CSIRO Land and Water Flagship, Locked Bag 2007, Kirrawee, NSW 2232 (Australia); Vallotton, Pascal [Digital Productivity Flagship, CSIRO, North Ryde, NSW 1670 (Australia); Apte, Simon C. [Centre for Environmental Contaminants Research, CSIRO Land and Water Flagship, Locked Bag 2007, Kirrawee, NSW 2232 (Australia)

    2015-11-15

    Highlights: • Nanoparticulate CeO{sub 2} less toxic than micron-sized CeO{sub 2}. • UV light filters prevented ROS generation by CeO{sub 2}. • ROS not toxic mechanism: CeO{sub 2} toxicity was similar in presence and absence of ROS. • Strong sorption of nanoparticulate CeO{sub 2} to Pseudokirchneriella subcapitata in synthetic fresh water. • CeO{sub 2} sorption to cells was prevented and toxicity mitigated in the presence of DOC. - Abstract: The factors affecting the chronic (72-h) toxicity of three nanoparticulate (10–34 nm) and one micron-sized form of CeO{sub 2} to the green alga, Pseudokirchneriella subcapitata were investigated. To characterise transformations in solution, hydrodynamic diameters (HDD) were measured by dynamic light scatter, zeta potential values by electrophoretic mobility, and dissolution by equilibrium dialysis. The protective effects of humic and fulvic dissolved organic carbon (DOC) on toxicity were also assessed. To investigate the mechanisms of algal toxicity, the CytoViva hyperspectral imaging system was used to visualise algal–CeO{sub 2} interactions in the presence and absence of DOC, and the role of reactive oxygen species (ROS) was investigated by ‘switching off’ ROS production using UV-filtered lighting conditions. The nanoparticulate CeO{sub 2} immediately aggregated in solution to HDDs measured in the range 113–193 nm, whereas the HDD and zeta potential values were significantly lower in the presence of DOC. Negligible CeO{sub 2} dissolution over the time course of the bioassay ruled out potential toxicity from dissolved cerium. The nanoparticulate CeO{sub 2} concentration that caused 50% inhibition of algal growth rate (IC50) was in the range 7.6–28 mg/L compared with 59 mg/L for micron-sized ceria, indicating that smaller particles were more toxic. The presence of DOC mitigated toxicity, with IC50s increasing to greater than 100 mg/L. Significant ROS were generated in the nanoparticulate CeO{sub 2

  9. Production properties of the orbitally excited mesons f sub 0 (980), f sub 2 (1270), K sup * sup 0 sub 2 (1430) and f' sub 2 (1525) in Z sup 0 hadronic decays

    CERN Document Server

    Uvarov, V

    2000-01-01

    DELPHI results are presented on the inclusive production of the neutral mesons rho sup 0 , f sub 0 (980), f sub 2 (1270), K sup * sup 0 sub 2 (1525) in hadronic Z sup 0 decays. They are based on about 2 million multihadronic events collected in 1994 and 1995, using the particle identification capabilities of the DELPHI Ring Imaging Cherenkov detectors and measured ionization losses in the Time Projection Chamber. The total production rates per hadronic Z sup 0 decay have been determined to be: 1.19+-0.10 for rho sup 0; 0.164+-0.021 for f sub 0 (980); 0.214+-0.038 for f sub 2 (1270); 0.073 +- 0.023 for K sup * sup 0 sub 2 (1430); and 0.012 +- 0.006 for f' sub 2 (1525). The total production rates for all mesons and differential cross-sections for the rho sup 0 , f sub 0 (980) and f sub 2 (1270) are compared with the results of other LEP experiments and with models.

  10. WS{sub 2} nanotube formation by sulphurization: Effect of precursor tungsten film thickness and stress

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Sheung Mei; Wong, Hon Fai; Wong, Wang Cheung; Tan, Choon Kiat; Choi, Sin Yuk; Mak, Chee Leung; Li, Gui Jun [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Dong, Qing Chen [MOE Key Laboratory for Interface Science and Engineering in Advanced Materials and Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, 79 Yingze West Street, Taiyuan 030024 (China); Leung, Chi Wah, E-mail: dennis.leung@polyu.edu.hk [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2016-09-15

    Transition metal dichalcogenides can exhibit as 2-dimensional layers, 1-dimensional nanotubes or 0-dimensional quantum dot structures. In general, dichalcogenide nanotubes are grown under stringent conditions, using high growth temperatures with tedious processes. Here, we report the controlled formation of tungsten disulphide (WS{sub 2}) nanostructures by manipulating the precursor film thickness, followed by a direct sulphurization process. WS{sub 2} nanotubes were formed by ultra-thin tungsten precursor films, while particle-like WS{sub 2} were obtained from thicker tungsten films under identical sulphurization conditions. To elucidate the origin of WS{sub 2} nanostructure formation, micron-sized tungsten film tracks were prepared, and such patterned films were found to suppress the growth of WS{sub 2} nanotubes. We attribute the suppression of nanotube formation to the relieving of film stress in patterned precursor films. - Highlights: • WS{sub 2} were obtained by sulphurization of sputtered tungsten films on Si substrates. • Resultant WS{sub 2} nanostructure morphology was dependent on precursor film thickness. • Patterning into micro-size W tracks suppressed the formation of nanotubes. • Stress relaxation was attributed as controlling factor for WS{sub 2} structure formation.

  11. Investigation on structural, surface morphological and dielectric properties of Zn-doped SnO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sagadevan, Suresh [Department of Physics, AMET University, Chennai (India); Podder, Jiban, E-mail: sureshsagadevan@gmail.com [Department of Chemical and Biological Engineering, University of Saskatchewan (Canada)

    2016-03-15

    Zinc doped Tin oxide (SnO{sub 2}) nanoparticles were prepared by co-precipitation method. The average crystallite size of pure and Zn-doped SnO{sub 2} nanoparticles was calculated from the X-ray diffraction (XRD) pattern. The FT-IR spectrum indicated the strong presence of SnO{sub 2} nanoparticles. The morphology and the particle size were studied using the scanning electron microscope (SEM) and transmission electron microscope (TEM). The particle size of the Zn-doped SnO{sub 2} nanoparticles was also analyzed, using the Dynamic Light Scattering (DLS) experiment. The optical properties were studied by the UV-Visible absorption spectrum. The dielectric properties of Zn-doped SnO{sub 2} nanoparticles were studied at different frequencies and temperatures. The ac conductivity of Zn-doped SnO{sub 2} nanoparticles was also studied. (author)

  12. Can reduced size of metals induce hydrogen absorption: ZrAl{sub 2} case

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, I., E-mail: izi@bgu.ac.il [Department of Nuclear Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105 (Israel); Deledda, S. [Physics Department, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway); Bereznitsky, M. [Department of Nuclear Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105 (Israel); Yeheskel, O. [Nuclear Research Center - Negev, P.O. Box 9001, Beer Sheva 84190 (Israel); Filipek, S.M. [Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw (Poland); Mogilyanski, D.; Kimmel, G. [Institute for Applied Research, P.O. Box 653, Ben-Gurion University of the Negev, Beer Sheva 84105 (Israel); Hauback, B.C. [Physics Department, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway)

    2011-09-15

    Research highlights: > 15 nm particles of ZrAl{sub 2} and Zr(Al{sub 0.5}Co{sub 0.5}){sub 2} are obtained by attrition and cryomilling. > ZrAl{sub 2} nanoparticles remain inert to hydrogen absorption up to pressure of {approx}2 GPa. > Zr(Al{sub 0.5}Co{sub 0.5}){sub 2} nanoparticles exhibit reduced hydrogen absorption as compared to the corresponding bulk compounds. - Abstract: The hydrogen absorption ability of the non-absorbing Al-rich ZrAl{sub 2} compound was examined after reducing its particles-size to the nanometer regime. The hydrogen abstinence of bulk ZrAl{sub 2} has been previously related to its excessive elastic shear stiffening. The particle size of ZrAl{sub 2} was reduced by attrition milling and cryomilling. The minimal average particle size was estimated from powder X-ray diffraction analysis to be in the range of 10-20 nm. The hydrogen absorption of the milled compounds was measured in different hydrogenation systems at hydrogen pressures between {approx}6 MPa and {approx}2 GPa. In all the cases the hydrogen absorption was negligible. In addition, there was a reduction of the hydrogen absorption capacity of nanosized Zr(Al{sub 0.5}Co{sub 0.5}){sub 2} as compared to the corresponding bulk compound at the same conditions. We suggest, in view of our and other results, that no significant improvement of the thermodynamics (unlike the kinetics) of the hydrogen absorption can be achieved via the nanoparticle avenue.

  13. In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7} heterostructured nanoparticles with enhanced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Yonglei [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic and Information Engineering, State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Que, Wenxiu, E-mail: wxque@mail.xjtu.edu.cn [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic and Information Engineering, State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Yin, Xingtian; He, Zuoli; Liu, Xiaobin; Yang, Yawei; Shao, Jinyou [Electronic Materials Research Laboratory, International Center for Dielectric Research, Key Laboratory of the Ministry of Education, School of Electronic and Information Engineering, State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Kong, Ling Bing, E-mail: ELBKong@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore)

    2016-11-30

    Highlights: • Visible-light photocatalytic activities of the nanostructured In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7} heterostructures were studied. • Effect of In{sub 2}O{sub 3} content on the photocatalytic activity of the In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7} heterostructure was evaluated. • 0.1In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7} heterostructure photocatalyst shows a superior photocatalytic activity. • Based on Mott-Schottky analysis and active species detection, a mechanism for the separation of photogenerated carriers is proposed. • The effective separation process of the photogenerated electron-hole pairs was testified by photocurrent test. - Abstract: In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7} composite photocatalysts with various contents of cubic In{sub 2}O{sub 3} nanoparticles were fabricated by using impregnation method. A thriving modification of Bi{sub 2}Sn{sub 2}O{sub 7} by an introduction of In{sub 2}O{sub 3} was confirmed by using X-ray diffraction, UV–vis diffuse reflectance spectrometry, transmission electron microscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The samples composed of hybrids of In{sub 2}O{sub 3} and Bi{sub 2}Sn{sub 2}O{sub 7} exhibited a much higher photocatalytic activity for the degradation of Rhodamine B under visible light, as compared with pure In{sub 2}O{sub 3} and Bi{sub 2}Sn{sub 2}O{sub 7} nanoparticles. Optimized composition of the composite photocatalysts was 0.1In{sub 2}O{sub 3}/Bi{sub 2}Sn{sub 2}O{sub 7}, which shows a rate constant higher than those of pure In{sub 2}O{sub 3} and Bi{sub 2}Sn{sub 2}O{sub 7} by 4.06 and 3.21 times, respectively. Based on Mott-Schottky analysis and active species detection, the photoexcited electrons in the conduction band of In{sub 2}O{sub 3} and the holes in the valence band of Bi{sub 2}Sn{sub 2}O{sub 7} participated in reduction and oxidation reactions, respectively. Hence, ·OH, ·O{sub 2}{sup −} and h

  14. Band structure and photocatalytic activities for H{sub 2} production of ABi{sub 2}Nb{sub 2}O{sub 9} (A = Ca, Sr, Ba)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yingxuan; Chen, Gang; Zhang, Hongjie; Lv, Zushun [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

    2010-04-15

    A new series of layered perovskite photocatalysts, ABi{sub 2}Nb{sub 2}O{sub 9} (A = Ca, Sr, Ba), were synthesized by the conventional solid-state reaction method and characterized by X-ray diffraction (XRD) and UV-visible spectrometer. The results showed that the structure of ABi{sub 2}Nb{sub 2}O{sub 9} (A = Ca, Sr) is orthorhombic, while that of BaBi{sub 2}Nb{sub 2}O{sub 9} is tetragonal. The band gaps of CaBi{sub 2}Nb{sub 2}O{sub 9}, SrBi{sub 2}Nb{sub 2}O{sub 9}, and BaBi{sub 2}Nb{sub 2}O{sub 9} were estimated to be 3.46, 3.43, and 3.30 eV, respectively. It was found from the electronic band structure study, using the density functional theory (DFT) with planewave basis, that the conduction bands of these photocatalysts mainly consist of Nb 4d + Bi 6p + O 2p orbitals and the valence bands are composed of hybridization with O 2p + Nb 4d + Bi 6s orbitals. The photocatalytic activities for water splitting were investigated under UV-light irradiation and indicated that these photocatalysts showed photocatalytic activity for H{sub 2} and O{sub 2} evolution from aqueous solutions containing sacrificial reagents (methanol and Ag{sup +}). (author)

  15. Kinetic improvement on the CaH{sub 2}-catalyzed Mg(NH{sub 2}){sub 2} + 2LiH system

    Energy Technology Data Exchange (ETDEWEB)

    Torre, Francesco; Valentoni, Antonio [Department of Chemistry and Pharmacy, University di Sassari and INSTM, Via Vienna 2, I-07100 Sassari (Italy); Milanese, Chiara [Pavia Hydrogen Lab, Dipartimento di Chimica, Sezione di Chimica Fisica, Università di Pavia, V.le Taramelli 16, 27100 Pavia (Italy); Pistidda, Claudio [Institute of Materials Research, Materials Technology, Helmholtz-Zentrum Geesthacht, Max-Planck, Str. 1, D-21502 Geesthacht (Germany); Marini, Amedeo [Pavia Hydrogen Lab, Dipartimento di Chimica, Sezione di Chimica Fisica, Università di Pavia, V.le Taramelli 16, 27100 Pavia (Italy); Dornheim, Martin [Institute of Materials Research, Materials Technology, Helmholtz-Zentrum Geesthacht, Max-Planck, Str. 1, D-21502 Geesthacht (Germany); Enzo, Stefano; Mulas, Gabriele [Department of Chemistry and Pharmacy, University di Sassari and INSTM, Via Vienna 2, I-07100 Sassari (Italy); Garroni, Sebastiano, E-mail: sgarroni@uniss.it [Department of Chemistry and Pharmacy, University di Sassari and INSTM, Via Vienna 2, I-07100 Sassari (Italy)

    2015-10-05

    Highlights: • We studied the effect of CaH{sub 2} on the dehydrogenation of the Mg(NH{sub 2}){sub 2}–2LiH system. • Mg(NH{sub 2}){sub 2} was obtained by gas–solid reaction with a significant conversion degree. • Kissinger analysis revealed that addition of CaH{sub 2} decreased the activation energy. - Abstract: In the present work we focused on the catalytic effect of CaH{sub 2} on the dehydrogenation process of the Mg(NH{sub 2}){sub 2}–2LiH system. The synthesis, hydrogen storage properties and energy barriers were investigated by X-ray diffraction (XRD), temperature-programmed desorption (TPD) and differential scanning calorimetry (DSC). The TPD measurements proved that desorption of the Mg(NH{sub 2}){sub 2}–2LiH system milled with 0.08 mol of CaH{sub 2} started at temperature of 78 °C, lower if compared with the 125 °C observed in the pristine material. Furthermore, Kissinger analysis revealed that CaH{sub 2} acted as a catalyst to decrease the activation energy of the first dehydrogenation step from a value of 133.8 ± 4.1 kJ/mol for the pristine material to 105.1 ± 3.2 kJ/mol when CaH{sub 2} was dispersed into the mixture.

  16. Capacitive properties of PANI/MnO{sub 2} synthesized via simultaneous-oxidation route

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jie [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Shu Dong, E-mail: dshu@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Tianneng Group, Changxing 313100, Zhejiang Province (China); Base of Production, Education and Research on Energy Storage and Power Battery of Guangdong Higher Education Institutes, Guangzhou 510006 (China); Key Laboratory of Electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes, South China Normal University, Guangzhou 510006 (China); Zhang Tianren [Tianneng Group, Changxing 313100, Zhejiang Province (China); Chen Hongyu [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Base of Production, Education and Research on Energy Storage and Power Battery of Guangdong Higher Education Institutes, Guangzhou 510006 (China); Key Laboratory of Electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes, South China Normal University, Guangzhou 510006 (China); Zhao Haimin; Wang Yongsheng [Tianneng Group, Changxing 313100, Zhejiang Province (China); Sun Zhenjie; Tang Shaoqing [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Fang Xueming [Tianneng Group, Changxing 313100, Zhejiang Province (China); Cao Xiufang [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer PANI/MnO{sub 2} composite was synthesized by the simultaneous-oxidation route. Black-Right-Pointing-Pointer Good contact in inter-molecule level between PANI and MnO{sub 2} improves the conductivity. Black-Right-Pointing-Pointer The separation between PANI and MnO{sub 2} prevents the aggregation of nano-composite. Black-Right-Pointing-Pointer The maximum specific capacitance of the PANI/MnO{sub 2} electrode is 320 F/g. Black-Right-Pointing-Pointer The as-prepared PANI/MnO{sub 2} exhibits excellent cycle stability of 84% capacitance retention after 10,000 cycles. - Abstract: Polyaniline (PANI) and manganese dioxide (MnO{sub 2}) composite (PANI/MnO{sub 2}) was synthesized via a simultaneous-oxidation route. In this route, all reactants were dispersed homogenously in precursor solution and existed as ions and molecules, and involved reactions of ions and molecules generating PANI and MnO{sub 2} simultaneously. In this way, PANI molecule and MnO{sub 2} molecule contact each other and arrange alternately in the composite. The inter-molecule contact improves the conductivity of the composite. The alternative arrangement of PANI molecules and MnO{sub 2} molecules separating each other, and prevents the aggregation of PANI and cluster of MnO{sub 2} so as to decrease the particle size of the composite. The morphology, structure, porous and capacitive properties are characterized by scanning electron microscopy, X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, Branauer-Emmett-Teller test, thermogravimetric analysis, Fourier transform infrared spectroscopy, cyclic voltammetry, charge-discharge test and the electrochemical impedance measurements. The results show that MnO{sub 2} is predominant in the PANI/MnO{sub 2} composite and the composite exhibits larger specific surface area than pure MnO{sub 2}. The maximum specific capacitance of the composite electrode reaches up to 320 F/g by charge-discharge test, 1.56 times

  17. Methane decomposition over high-loaded Ni-Cu-SiO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jiamao; Zhao, Linjie; He, Jianchao; Dong, Liang; Xiong, Liangping; Du, Yang; Yang, Yong; Wang, Heyi, E-mail: hywang@caep.cn; Peng, Shuming, E-mail: pengshuming@caep.cn

    2016-12-15

    Graphical abstract: Methane decomposition-regeneration with air cycles over 65%Ni-20%Cu-10%SiO{sub 2} catalysts. - Highlights: • Methane decomposition over Ni-Cu-SiO{sub 2} was studied. • The deactivated catalysts were regenerated by air. • Introduction of Cu could enhance the catalytic performance of Ni-SiO{sub 2}. • The increase of the Ni-Cu particle influences the performance of the catalysts. - Abstract: The performance of Ni-SiO{sub 2} and Ni-Cu-SiO{sub 2} during repeated catalytic decomposition of methane (CDM) reactions and subsequent regeneration of the deactivated catalysts with air has been studied. The catalytic activity of the 75%Ni-25%SiO{sub 2} catalyst in the second and third CDM was lower than that during the first, while the lifetime of the catalyst did not change significantly. Both the lifetime and the catalytic activity of 65%Ni-10%Cu-25%SiO{sub 2} in the second and third CDM reactions decreased significantly. 55%Ni-20%Cu-25%SiO{sub 2} showed better performance than the other two catalysts, and its activity and lifetime did not change significantly until the third CDM reaction. The hydrogen yields of 55%Ni-20%Cu-25%SiO{sub 2} were 56.8 gH{sub 2}/gcat., 42.8 gH{sub 2}/gcat., and 2.4 gH{sub 2}/gcat. for the first, second, and third CDM reactions, respectively. Spherical carbon structures were observed on the catalysts following all three CDM reactions over 75%Ni-25%SiO{sub 2}. However, similar carbon structures were only observed following the second and third CDM over 65%Ni-10%Cu-25%SiO{sub 2}, and only following the third cycle with 55%Ni-20%Cu-25%SiO{sub 2}. The formation of spherical carbon during the repeated CDM reactions strongly influenced the performance of the catalysts.

  18. Colloidal processing and CO{sub 2}-capture performance Al{sub 2}O{sub 3}-zeolite 13X composites

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, L.; Akhtar, F.; Ojuva, A.; Bergstroem, L. [Stockholm Univ. (Sweden). Dept. of Materials and Environmental Chemistry

    2012-07-01

    Hierarchically porous composites for CO{sub 2}-capture have been produced by coating the inner walls of foam-like macroporous alumina monoliths, produced by templated synthesis, with microporous zeolite 13X particles. Homogeneous and dense coatings of the particulate adsorbent were obtained when the impregnation process was performed at a pH above 9. At this pH-level the colloidally stable suspensions of the negatively charged zeolite 13X particles could fill all the voids of the highly connected pore space of the alumina supports and attach to the monolith walls, which had been pre-coated with poly(ethylene imine). A CO{sub 2}-uptake as high as 5 mmol CO{sub 2}/g zeolite 13X was achieved for alumina-zeolite 13X composites through minimisation of the added inorganic binder, kaolin, to only 3.0 wt% with respect to zeolite content, and through optimisation of the thermal treatment.

  19. Thermal conductivity of powders with UO/sub 2/ or ThO/sub 2/ microspheres in various gases from 300 to 1300 K

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.P.; Dippenaar, R.J.; Hall, R.O.A.; McElroy, D.L.

    1982-01-01

    The thermal conductivities of powders consisting of ThO/sub 2/ or UO/sub 2/ microspheres in He, Ar, N/sub 2/, and Kr were measured by two techniques over a pressure range of 0.03 to 0.6 MPa and a temperature range of 300 to 1300 K. The powders had solid volume packing fractions from 58.5 to 86.6% and were prepared by vibratory compaction and by mixing. The highest thermal conductivity measured was for powder containing three particle sizes at a packing fraction of 86.6% in helium gas. The applicability of the data to practical reactor fuels is limited to the early stages of fuel burnup because of restructing. A theoretical model is derived for heat transfer in powders with spherical particles.

  20. Bad-metal-layered sulfide oxide CsV{sub 2}S{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Valldor, Martin; Merz, Patrick; Prots, Yurii; Schnelle, Walter [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany)

    2016-01-15

    Through a solid-state reaction between stoichiometric amounts of a mixed cesium oxide Cs{sub 2}O{sub 1.3}, VS, S, and V{sub 2}O{sub 5}, a polycrystalline powder of CsV{sub 2}S{sub 2}O was obtained. Small single crystals could be grown in a CsCl melt by allowing Cs{sub 2}SO{sub 4}, V metal and S powders to react. The crystals have a plate-like morphology, consistent with the tetragonal crystal-structure symmetry [P4/mmm, a = 3.9455(1), c = 7.4785(1) Aa]. Magnetic measurements suggest that CsV{sub 2}S{sub 2}O is a temperature-independent paramagnet, and resistivity data concur with a bad metal. The mixed oxidation state of V on one crystallographic site offers a tentative explanation of the electronic properties of the title compound. (Abstract Copyright, Wiley Periodicals, Inc.)

  1. Transport measurements of lateral MgB{sub 2}/Fe/MgB{sub 2} junctions

    Energy Technology Data Exchange (ETDEWEB)

    Fabretti, Savio; Thomas, Patrick; Schaefers, Markus; Schebaum, Oliver; Thomas, Andy [Bielefeld University (Germany)

    2012-07-01

    We fabricated MgB{sub 2}/Fe/MgB{sub 2} lateral junctions by rf-dc co-sputtering. The MgB{sub 2} films have a thickness of about 30nm and a critical temperature of up to 33 K. The samples were annealed in-situ between 450 C and 750 C. Our MgB{sub 2} films were sputtered on different substrates such as (100)MgO and r-cut sapphire. Their crystalline structure and magnetic anisotropy were investigated. For transport measurement a thin iron cross strip of about 30 nm was placed between the MgB{sub 2} strip. The MgB{sub 2} strip was relieved by a groove of about 5 {mu}m. The superconductivity of MgB{sub 2} is suppressed due to the proximity effect near the junction area and builds a natural metallic barrier. With this configuration, we get a magnetoresistance due to the domain wall scattering in iron where the magnetoresistance was measured perpendicular and in plane of this array. Further, we investigated their I-V and dI/dV characteristics in dependence of an applied magnetic field up to 4T. The {sigma} gap as well as the {pi} gap was observed.

  2. Surface crystallization in a Li{sub 2}O-ZrO{sub 2}-SiO{sub 2}-Al{sub 2}O{sub 3} glass; Cristalizacao de superficie em vidro do sistema Li{sub 2}O-ZrO{sub 2}-SiO{sub 2}-Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Antonio Pedro Novaes de; Teixeira, Alexandre Henrique Bortolotto; Venturelli, Hugo Henrique, E-mail: bortolotto_teixeira@yahoo.com.br, E-mail: venturellihugo@gmail.com, E-mail: antonio.pedro@ufsc.br [Universidade Federal de Santa Catarina (VITROCER/PGMAT/UFSC), Florianopolis, SC (Brazil). Laboratorio de Materiais Vitroceramicos; Montedo, Oscar Rubem Klegues, E-mail: oscar.rkm@gmail.com [Universidade do Extremo Sul Catarinense (CERTEC/PPGCEM/UNESC), Criciuma, SC (Brazil). Grupo de Pesquisa em Ceramica Tecnica

    2017-04-15

    Growth kinetics of crystallized surface layer in a LZSA glass composition, 11.7Li{sub 2}O·12.6ZrO{sub 2}·68.6SiO{sub 2}·7.1Al{sub 2}O{sub 3} (wt%), was studied. For the production of the LZSA glass, it was used commercial raw materials (Li{sub 2}CO{sub 3}, ZrSiO{sub 4}, SiO{sub 2}, Al{sub 2}O{sub 3}) which were mixed and melted at 1550 °C for 120 min and then poured into a metallic mold. Samples of the obtained glass were cut and subjected to heat treatments at different temperatures (825 - 925 °C) and times (30 - 150 min) for formation and growth of crystalline layer. Cross-sections of the heat-treated samples were ground and polished such that images of the formed crystallized layers could be visualized and measured by microscopy. Results showed that it is possible to obtain LZSA glasses with crystallized layers formed by β-spodumene, zircon and lithium silicate, which present thicknesses between 13 and 665 μ and grow at rates varying from 0.4 to 4.8 μm/min in the studied temperature range. (author)

  3. Unusual antiferromagnetic structure of YbCo{sub 2}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mufti, N. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Department of Physics, State University of Malang, Malang (Indonesia); Kaneko, K. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai (Japan); Hoser, A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Berlin (Germany); Gutmann, M. [ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot (United Kingdom); Geibel, C.; Stockert, O. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Krellner, C. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Physikalisches Institut, Goethe-Universitaet Frankfurt, Frankfurt (Germany)

    2016-07-01

    We report on extensive powder and single crystal neutron diffraction experiments to study the magnetic structure in YbCo{sub 2}Si{sub 2} below the Neel temperature T{sub N} = 1.7 K in detail. Representation analysis has been used to find the possible magnetic structure models compatible with the experiments. Two different magnetically ordered phases can clearly be distinguished. At lowest temperatures a commensurate magnetic structure with a propagation vector k{sub 1} = (0.25 0.25 1) and equal moments or about 1.4 μ{sub B}/Yb is found, while the intermediate phase (T > 0.9 K) is characterized by an incommensurate amplitude-modulated magnetic structure with k{sub 2} = (0.25 0.086 1). The magnetic structure in YbCo{sub 2}Si{sub 2} is in stark contrast to all other compounds of the RCo{sub 2}Si{sub 2} family (R = rare earth element) likely due to some itineracy of the Yb 4f states being responsible for the magnetism.

  4. Study of the optical conductivity of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} material

    Energy Technology Data Exchange (ETDEWEB)

    Bhuiyan, E.H., E-mail: hoque.phy@gmail.com [Department of Physics, Jagannath University, 9-10, Chittaranjan Avenue, Dhaka 1100 (Bangladesh); Presenza-Pitman, G. [Department of Physics, University of Toronto, St. George St., Toronto, Ontario, M5S 1A7 (Canada); Azzouz, M. [Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, Ontario, P3E 2C6 (Canada)

    2012-02-15

    We studied the optical conductivity of the Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} materials in the normal state as well as in the superconducting state as a function of temperature and doping within the rotating antiferromagnetism theory (RAFT) using the Marginal Fermi Liquid (MFL) ansatz for self-energy. The optical conductivity is calculated using Nambu formalism and Kubo's formula. Experimental data for Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} are discussed.

  5. Synthesis and characterization of Cu{sub 2}O/TiO{sub 2} photocatalysts for H{sub 2} evolution from aqueous solution with different scavengers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yanping; Wang, Baowei, E-mail: wangbw@tju.edu.cn; Liu, Sihan; Duan, Xiaofei; Hu, Zongyuan

    2015-01-01

    Graphical abstract: - Highlights: • Cu{sub 2}O/TiO{sub 2} photocatalyst are prepared by a facile ethanol reduction method. • The heterojunction between p-type Cu{sub 2}O and n-type TiO{sub 2} improves activity of TiO{sub 2}. • An optimal molar fraction of Cu{sub 2}O is reported in Cu{sub 2}O/TiO{sub 2} photocatalysts. • The effect of different alcohols scavengers on activity of Cu{sub 2}O/TiO{sub 2} is discussed. - Abstract: A series of Cu{sub 2}O/TiO{sub 2} photocatalysts with different molar fraction of Cu{sub 2}O were prepared by a facile modified ethanol-induced approach followed by a calcination process. The chemical state of copper compound was proved to be cuprous oxide by the characterization of X-ray photoelectron spectra (XPS). Furthermore, these composite oxides were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N{sub 2} adsorption desorption and UV–vis techniques to study the morphologies, structures, and optical properties of the as-prepared samples. The results indicated that the photocatalytic activity of n-type TiO{sub 2} was significantly enhanced by combined with p-type Cu{sub 2}O, due to the efficient p–n heterojunction. The p–n heterojunction between Cu{sub 2}O and TiO{sub 2} can enhance visible-light adsorption, efficiently suppress charge recombination, improve interfacial charge transfer, and especially provide plentiful reaction active sites on the surface of photocatalyst. As a consequence, the prepared 2.5-Cu{sub 2}O/TiO{sub 2} photocatalyst exhibited the highest photocatalytic activity for H{sub 2} evolution rate and reached 2048.25 μmol/(g h), which is 14.48 times larger than that of pure P25. The apparent quantum yield (AQY) of the 2.5-Cu{sub 2}O/TiO{sub 2} sample at 365 nm was estimated to be 4.32%. In addition, the influence of different scavengers, namely methanol, anhydrous ethanol, ethylene glycol and glycerol, on the photocatalytic activity for H{sub 2} evolution rate was

  6. MoS{sub 2} on an amorphous HfO{sub 2} surface: An ab initio investigation

    Energy Technology Data Exchange (ETDEWEB)

    Scopel, W. L., E-mail: wlscopel@if.uff.br [Departamento de Física, Universidade Federal do Espírito Santo, Vitória, Brazil and Departamento de Ciências Exatas, Universidade Federal Fluminense, Volta Redonda, Rio de Janerio (Brazil); Miwa, R. H., E-mail: hiroki@infis.ufu.br; Schmidt, T. M., E-mail: tome@infis.ufu.br [Instituto de Física, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais (Brazil); Venezuela, P., E-mail: vene@if.uff.br [Instituto de Física, Universidade Federal Fluminense, Niterói, Rio de Janerio (Brazil)

    2015-05-21

    The energetic stability, electronic and structural properties of MoS{sub 2} adsorbed on an amorphous a-HfO{sub 2} surface (MoS{sub 2}/HfO{sub 2}) are examined through ab initio theoretical investigations. Our total energy results indicate that the formation of MoS{sub 2}/HfO{sub 2} is an exothermic process with an adsorption energy of 34 meV/Å{sup 2}, which means that it is more stable than similar systems like graphene/HfO{sub 2} and MoS{sub 2}/SiO{sub 2}. There are no chemical bonds at the MoS{sub 2}-HfO{sub 2} interface. Upon formation of MoS{sub 2}/HfO{sub 2}, the electronic charge distribution is mostly localized at the interface region with no net charge transfer between the adsorbed MoS{sub 2} sheet and –HfO{sub 2} surface. However, the MoS{sub 2} sheet becomes n-type doped when there are oxygen vacancies in the HfO{sub 2} surface. Further investigation of the electronic distribution reveals that there are no electron- and hole-rich regions (electron-hole puddles) on the MoS{sub 2} sheet, which makes this system promising for use in high-speed nanoelectronic devices.

  7. Antiferromagnetic transition in EuCu sub 2 Ge sub 2 single crystals

    CERN Document Server

    Hossain, Z; Yuan, H Q; Sparn, G

    2003-01-01

    Single crystals of EuCu sub 2 Ge sub 2 were grown and characterized using electrical resistivity, magnetization, specific heat and magnetoresistance measurements. The crystals exhibit antiferromagnetic transitions at T sub N sub 1 = 9 K and T sub N sub 2 = 5 K. The T sub N of the flux-grown single crystals reported here are lower than that reported for the polycrystalline sample (T sub N = 13 K) in the literature (Felner and Nowik 1978 J. Phys. Chem. Solids 39 763). The magnetoresistance is positive in the ordered state and negative in the paramagnetic state. The magnetic order could not be suppressed up to a pressure of 25 kbar.

  8. Preparation of Ag/TiO{sub 2}/SiO{sub 2} films via photo-assisted deposition and adsorptive self-assembly for catalytic bactericidal application

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Baojuan, E-mail: baojuanxi@gmail.com [Department of Electrical and Computer Engineering, 10 Kent Ridge Crescent, Singapore 119260 (Singapore); Chu, Xiaona; Hu, Jiangyong [Department of Civil and Environmental Engineering, 10 Kent Ridge Crescent, Singapore 119260 (Singapore); Bhatia, Charanjit Singh; Danner, Aaron James; Yang, Hyunsoo [Department of Electrical and Computer Engineering, 10 Kent Ridge Crescent, Singapore 119260 (Singapore)

    2014-08-30

    Highlights: • We prepared controlledly the silver nanoparticles on TiO{sub 2}/SiO{sub 2} film by the facile photoreduction under the aid of structure-directing agents. • We studied the effect of silver loading on the antibactierial behavior of TiO{sub 2} film and optimized the content of silver. • We extended the route to fabricate other metals on substrates. - Abstract: The deterioration of water supply quality due to the waterborne bacteria is an environmental problem requiring the urgent attention. Due to the excellent and synergic antimicrobial capability, Ag-loaded TiO{sub 2} photocatalyst emerges as a feasible measure to guard the water. In our work, Ag nanoparticles have been prepared by the photoassisted reduction of AgNO{sub 3} on the TiO{sub 2} film fabricated by solution-based adsorptive self-assembly approach. The role of surfactant on the growth rate and size controlling of particles is also studied. In this connection, different kinds of surfactants, such as PVP, Tween-20, Tween-40 and so on, are applied in the system to investigate the formation of Ag nanoparticles. The surface profile and elemental analysis of Ag/TiO{sub 2}/SiO{sub 2} films are examined by scanning electron microscopy and attached energy-dispersive X-ray spectroscopy, respectively. In the anti-bacteria detection, Ag nanoparticles are found to enhance the bactericidal efficiency strongly comparing with the pure TiO{sub 2} film under the same condition. In addition, by comparison with Ag/TiO{sub 2}/SiO{sub 2} film in the dark environment as the reference experiment, UV–visible light plays a vital role in the improved bactericidal behavior, demonstrating the more efficient charge separation induced by metal silver. Because of the versatility of the method, the present photoreductive route is also exploited for the synthesis of Au nanoparticles on TiO{sub 2}/SiO{sub 2} films. The corresponding photocatalytical detection results demonstrate the loading of Au nanoparticles can

  9. Magnetic nanoparticles in MgB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sandu, Viorel, E-mail: viorelsandu51@yahoo.com [National Institute of Materials Physics, Str. Atomistilor 105 bis, Magurele 077125 (Romania); Chee, Ching Yern [Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Lembah Pantai, Kuala Lumpur (Malaysia)

    2014-03-15

    Highlights: • Critical current density in MgB{sub 2} composites with magnetic nanoparticles is analyzed. • A maximum in critical current occurs if the magnetization at T{sub c} is 0.015 emu/cm{sup 3}. • A tentative description in the framework of collective pinning is proposed. - Abstract: Additional pinning generated by magnetic nanoparticles which were created or inserted within polycrystalline MgB{sub 2} superconductor is analyzed. The composites were built in two ways: (i) ceramization of polysiloxane-co-ferrocene based copolymers and (ii) insertion of coated nanoparticles. The composites present two types of pinning: core pinning based on the variation of the superconducting parameter when a non-superconducting particle is present and a magnetic pinning resulting from the interaction of the screening currents around the particle and the flux line. All samples show a consistent improvement of the critical current density when the magnetic moment of the sample in normal state is finite but small, showing a maximum for a magnetic moment of 0.015 emu/cm{sup 3}. A tentative description of the effect of magnetic pinning is presented in the framework of the collective pinning.

  10. Efficient degradation of carbamazepine by easily recyclable microscaled CuFeO{sub 2} mediated heterogeneous activation of peroxymonosulfate

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yaobin, E-mail: yaobinding@mail.scuec.edu.cn [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China); Tang, Hebin [College of Pharmacy, South-Central University for Nationalities, Wuhan 430074 (China); Zhang, Shenghua; Wang, Songbo [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China); Tang, Heqing, E-mail: tangheqing@mail.scuec.edu.cn [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China)

    2016-11-05

    Highlights: • CuFeO{sub 2} microparticles were prepared by a microwave-assisted hydrothermal method. • CuFeO{sub 2} microparticles efficiently catalyzed the activation of peroxymonosulfate. • Quenching experiments confirmed sulfate radicals as the major reactive radicals. • Carbamazepine was rapidly degraded by micro-CuFeO{sub 2}/peroxymonosulfate. • Feasibility of CuFeO{sub 2}/peroxymonosulfate was tested for treatment of actual water. - Abstract: Microscaled CuFeO{sub 2} particles (micro-CuFeO{sub 2}) were rapidly prepared via a microwave-assisted hydrothermal method and characterized by scanning electron microscopy, X-ray powder diffraction and X-ray photoelectron spectroscopy. It was found that the micro-CuFeO{sub 2} was of pure phase and a rhombohedral structure with size in the range of 2.8 ± 0.6 μm. The micro-CuFeO{sub 2} efficiently catalyzed the activation of peroxymonosulfate (PMS) to generate sulfate radicals (SO{sub 4}·−), causing the fast degradation of carbamazepine (CBZ). The catalytic activity of micro-CuFeO{sub 2} was observed to be 6.9 and 25.3 times that of micro-Cu{sub 2}O and micro-Fe{sub 2}O{sub 3}, respectively. The enhanced activity of micro-CuFeO{sub 2} for the activation of PMS was confirmed to be attributed to synergistic effect of surface bonded Cu(I) and Fe(III). Sulfate radical was the primary radical species responsible for the CBZ degradation. As a microscaled catalyst, micro-CuFeO{sub 2} can be easily recovered by gravity settlement and exhibited improved catalytic stability compared with micro-Cu{sub 2}O during five successive degradation cycles. Oxidative degradation of CBZ by the couple of PMS/CuFeO{sub 2} was effective in the studied actual aqueous environmental systems.

  11. Selection of nanoparticles using CO.sub.2-expanded liquids

    Science.gov (United States)

    Roberts, Christopher B; McLeod, Marshall Chandler; Anand, Madhu

    2013-02-19

    A method for size selection of nanostructures comprising utilizing a gas-expanded liquids (GEL) and controlled pressure to precipitate desired size populations of nanostructures, e.g., monodisperse. The GEL can comprise CO.sub.2 antisolvent and an organic solvent. The method can be carried out in an apparatus comprising a first open vessel configured to allow movement of a liquid/particle solution to specific desired locations within the vessel, a second pressure vessel, a location controller for controlling location of the particles and solution within the first vessel, a inlet for addition of antisolvent to the first vessel, and a device for measuring the amount of antisolvent added. Also disclosed is a method for forming nanoparticle thin films comprising utilizing a GEL containing a substrate, pressurizing the solution to precipitate and deposit nanoparticles onto the substrate, removing the solvent thereby leaving a thin nanoparticle film, removing the solvent and antisolvent, and drying the film.

  12. Improvement of charge separation in TiO{sub 2} by its modification with different tungsten compounds

    Energy Technology Data Exchange (ETDEWEB)

    Tryba, B., E-mail: beata.tryba@zut.edu.pl; Tygielska, M.; Grzeskowiak, M.; Przepiorski, J.

    2016-04-15

    Highlights: • Ammonium m-tungstate doped to TiO{sub 2} highly improved charge separation in TiO{sub 2}. • Negative electrokinetic potential of TiO{sub 2} facilitates holes migration to its surface. • Fast migration of holes to TiO{sub 2} surfaces increased yield of OH radicals formation. • Adsorption of dyes on photocatalyst increased its decomposition under visible light. - Abstract: Three different tungsten precursors were used for TiO{sub 2} modification: H{sub 2}WO{sub 4}, WO{sub 2}, and ammonium m-tungstate. It was proved that modification of TiO{sub 2} with tungsten compounds enhanced its photocatalytic activity through the improvement of charge separation. This effect was obtained by coating of TiO{sub 2} particles with tungsten compound, which changed their surficial electrokinetical potential from positive onto negative. The most efficient tungsten compound, which caused enhanced separation of free carriers was ammonium m-tungstate (AMT). Two dyes with different ionic potential were used for the photocatalytic decomposition. It appeared that cationic dye—Methylene Blue was highly adsorbed on the negatively charged surface of TiO{sub 2} modified by AMT and decomposed, however this photocatalyst was quickly deactivated whereas anionic dye—acid red was better adsorbed on the less acidic surface of TiO{sub 2} and was rapidly decomposed with almost the same rate in the five following cycles.

  13. Theoretical reconsideration of antiferromagnetic Fermi surfaces in URu{sub 2}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Yamagami, Hiroshi, E-mail: yamagami@cc.kyoto-su.ac.jp [Department of Physics, Faculty of Science, Kyoto Sangyo University, Kyoto 603-8555 (Japan)

    2011-01-01

    In an itinerant 5f-band model, the antiferromagnetic (AFM) Fermi surfaces of URu{sub 2}Si{sub 2} are reconsidered using a relativistic LAPW method within a local spin-density approximation, especially taking into account the lattice parameters dependent on pressures. The reduction of the z-coordinate of the Si sites results in the effect of flattening the Ru-Si layers of URu{sub 2}Si{sub 2} crystal structure, thus weakening a hybridization/mixing between the U-5f and Ru-4d states in the band structure. Consequently the 5f bands around the Fermi level are more flat in the dispersion with decreasing the z-coordinate, thus producing three closed Fermi surfaces like 'curing-stone', 'rugby-ball' and 'ball'. The origins of de Haas-van Alphen branches can be qualitatively interpreted from the obtained AFM Fermi surfaces.

  14. Magnetization process in the antiferromagnet URu sub 2 Si sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Radwanski, R.J. (Van der Waals-Zeeman Lab., Univ. Amsterdam (Netherlands))

    1992-01-01

    The Crystalline-Electric-Field (CEF) based approach with a non-magnetic singlet vertical stroke-2> -vertical stroke+2>, resulting from higher-order CEF interactions, as the ground state for the {sup 3}H{sub 4} multiplet of the U{sup 4+} ion provides a very consistent explanation for many experimental features of URu{sub 2}Si{sub 2}. The magnetization process in URu{sub 2}Si{sub 2} is discussed in terms of the formation of the U{sup 4+}-ion moment by external fields taking into consideration the antiferromagnetic interactions. The metamagnetic transition at 36 T originates from crossing of the CEF levels. A scheme for the antiferromagnetic interactions of the U ions, in which the interaction between the 5f spins is mediated by 6d-electron spins, is proposed for U systems. (orig.).

  15. Spin transition in [Fe(phen){sub 2}(NCS){sub 2}] - {mu}SR study

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Y.; Boland, Y. [Unite de Chimie des Materiaux Inorganiques et Organiques, Departement de Chimie, Faculte des Sciences, Universite catholique de Louvain, Place Louis Pasteur 1, 1348 Louvain-la-Neuve (Belgium); Ksenofontov, V.; Guetlich, P. [Institut fuer Anorganische Chemie und Analytische Chemie, Universitaet Mainz, 55099 Mainz (Germany); Campbell, S.J. [School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2600 (Australia); Lord, J.S. [ISIS, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 OQX (United Kingdom)

    2004-12-01

    The reversible thermal spin transition which occurs in [Fe(phen){sub 2}(NCS){sub 2}] around T{sub 1/2} {proportional_to} 177 K has been investigated by muon spin relaxation ({mu}SR) ({proportional_to}10-280 K). The depolarisation curves are well described by two Lorentzian lines represent fast and slow components in the decay curves, with the initial asymmetry parameter of the fast component found to track the spin transition in [Fe(phen){sub 2}(NCS){sub 2}]. Comparison of zero-field and transverse field (20 Oe) {mu}SR measurements shows that diamagnetic muonic species occur over the entire temperature range. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Biological H{sub 2} from fuel gases and from H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, P.; Maness, P.C.; Rhodes, C.; Scahill, J.; Dundorf, S.; Martin, S. [National Renewable Energy Lab., Golden, CO (United States)

    1998-08-01

    The two stand-alone objectives of the research are to economically produce H{sub 2} in the near term from biomass (thermally gasified to syngas) and in the mid term from H{sub 2}O using cyanobacteria or algae with an oxygen-tolerant bacterial hydrogenase. Photosynthetic bacteria have four different terminal enzymes that mediate their H{sub 2} metabolisms--nitrogenase, uptake hydrogenase, fermentative hydrogenase, and carbon monoxide-linked hydrogenase. Each has been microbiologically and biochemically examined for their potential to specifically generate H{sub 2} in large-scale processes. Based on measurements of maximal activities, stabilities, energy requirements, equilibria, and partial pressures of the H{sub 2} producing reactions, the Co-linked hydrogenase is easily the most suited for practical applications. The enzyme mediates H{sub 2} production from CO at rates up to 3 mmol/min {center_dot} g cell dry weight at near ambient temperature and pressure. At biological temperatures, equilibrium for the CO shift into H{sub 2} lies far towards H{sub 2} production. Less than 0.1 ppm of CO remains after a 20% CO gas phase is acted upon by bacteria. The necessary contact time between CO and bacteria is approximately ten seconds. Similar biological activities are observed with thermally generated fuel gases. The product gas can be directly used in fuel cells. New bacterial isolates from nature and mutant strains are being selected to further improve the novel technology. Oxygen-resistant enzymes identified in some bacterial strains could lead to a more general, second generation technology mediating the solar production of H{sub 2} from H{sub 2}O. Presently, mass transfer of gaseous CO limits the bacterial production of H{sub 2} from fuel gases. New bioreactor designs have significantly enhanced shift rates. Vapor-phase and bubble-train bioreactors employing immobilized or suspended bacteria are being scaled up. A User Facility has been established for the safe

  17. Autogenic synthesis of SnO{sub 2} materials and their structural, electrochemical, and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Pol, V.G., E-mail: pol@anl.gov [Electrochemical Energy Storage Department, Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Calderon-Moreno, J.M. [Institute of Physical Chemistry Ilie Murgulescu, Romanian Academy, 202 Splaiul Independentei St., Bucharest 060021 (Romania); Thackeray, M.M. [Electrochemical Energy Storage Department, Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States)

    2012-12-15

    During autogenic reactions, organometallic precursors are decomposed above their critical temperature within an enclosed chamber at high temperatures and pressures. It has recently been established that such reactions can be used to synthesize carbon-coated metal oxide and metal phosphate nanoparticles. These materials are of interest as electrodes for lithium-ion batteries. In this paper, we report the autogenic fabrication of a carbon-coated SnO{sub 2} product and a carbon-free SnO{sub 2} product after removal of the carbon coating by combustion. The major objectives of the study were to monitor any beneficial effects that carbon-coated electrodes containing a lithium alloying element such as Sn might have in improving the electrical connectivity between electrode particles, which expand and contract significantly on lithiation and delithiation, and their utility in lithium cells. Specifically, we report the compositional, structural and morphological properties, and electrochemical behavior of carbon-coated SnO{sub 2} electrodes. Given the importance of the optical properties of SnO{sub 2}, we also describe the effects of the carbon coating on the optical absorbance and photoluminescence of autogenically-prepared SnO{sub 2} materials. - Graphical abstract: One-step, solvent-free autogenic reactions yield nanosized SnO{sub 2} nanoparticles, uniformly coated and interconnected by 2-4 nm carbon layers, with improved electrochemical performance. Highlights: Black-Right-Pointing-Pointer Distinctive autogenic process synthesized SnO{sub 2} nanoparticles coated with 2-4 nm carbon layers. Black-Right-Pointing-Pointer Carbon coating improved capacity retention and cycling stability of SnO{sub 2} nanoparticles. Black-Right-Pointing-Pointer Carbon coating quenched photoluminescence of SnO{sub 2} component in SnO{sub 2}-C composite. Black-Right-Pointing-Pointer Autogenic approach is extremely versatile, holds promise for designing new nanoarchitectures.

  18. Liquid CO<sub>2/Coal Slurry for Feeding Low Rank Coal to Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Marasigan, Jose [Electric Power Research Institute, Inc., Palo Alto, CA (United States); Goldstein, Harvey [Electric Power Research Institute, Inc., Palo Alto, CA (United States); Dooher, John [Electric Power Research Institute, Inc., Palo Alto, CA (United States)

    2013-09-30

    This study investigates the practicality of using a liquid CO<sub>2/coal slurry preparation and feed system for the E-Gas™ gasifier in an integrated gasification combined cycle (IGCC) electric power generation plant configuration. Liquid CO<sub>2 has several property differences from water that make it attractive for the coal slurries used in coal gasification-based power plants. First, the viscosity of liquid CO<sub>2 is much lower than water. This means it should take less energy to pump liquid CO<sub>2 through a pipe compared to water. This also means that a higher solids concentration can be fed to the gasifier, which should decrease the heat requirement needed to vaporize the slurry. Second, the heat of vaporization of liquid CO<sub>2 is about 80% lower than water. This means that less heat from the gasification reactions is needed to vaporize the slurry. This should result in less oxygen needed to achieve a given gasifier temperature. And third, the surface tension of liquid CO<sub>2 is about 2 orders of magnitude lower than water, which should result in finer atomization of the liquid CO<sub>2 slurry, faster reaction times between the oxygen and coal particles, and better carbon conversion at the same gasifier temperature. EPRI and others have recognized the potential that liquid CO<sub>2 has in improving the performance of an IGCC plant and have previously conducted systemslevel analyses to evaluate this concept. These past studies have shown that a significant increase in IGCC performance can be achieved with liquid CO<sub>2 over water with certain gasifiers. Although these previous analyses had produced some positive results, they were still based on various assumptions for liquid CO<sub>2/coal slurry properties.

  19. Poly(lactic acid)/TiO{sub 2} nanocomposites as alternative biocidal and antifungal materials

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Carmen; Ochoa, Almudena [POLCA, Departamento de Ingeniería Mecánica, Química y Diseño Industrial, Escuela Técnica Superior de Ingeniería y Diseño Industrial, Universidad Politécnica de Madrid, Ronda de Valencia 3, Madrid (Spain); Ulloa, Maria Teresa; Alvarez, Eduardo [Programa de Microbiología y Micología. ICBM-Facultad de Medicina Universidad de Chile, Dirección, Avenida Independencia 1027, Comuna Independencia, Santiago (Chile); Canales, Daniel [Grupo Polímeros, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Casilla 40, Correo 33, Santiago (Chile); Zapata, Paula A., E-mail: paula.zapata@usach.cl [Grupo Polímeros, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Casilla 40, Correo 33, Santiago (Chile)

    2015-12-01

    Poly(lactic acid) (PLA) composites with titanium oxide (TiO{sub 2}) ~ 10-nm nanoparticles were produced by the melting process and their main properties were evaluated. The nanoparticles are homogeneously dispersed in the matrix with a low degree of agglomeration, as seen by transmission electron microscopy (TEM). The crystallinity temperature increased ~ 12% when 5 wt.% of TiO{sub 2} was added, showing that the nanoparticles acted as nucleating agents this trend was confirmed by optical images. The elastic modulus increased ~ 54% compared to neat PLA at 5 wt.% of nanoparticles. Despite these improvements, PLA/TiO{sub 2} nanocomposites showed lower shear viscosity than neat PLA, possibly reflecting degradation of the polymer due to the particles. Regarding biocidal properties, after 2 h of contact the PLA/TiO{sub 2} composites with 8 wt.% TiO{sub 2} showed a reduction of Escherichia coli colonies of ~ 82% under no UVA irradiation compared to pure PLA. This biocidal characteristic can be increased under UVA irradiation, with nanocomposites containing 8 wt.% TiO{sub 2} killing 94% of the bacteria. The PLA/TiO{sub 2} nanocomposites with 8 wt.% were also 99.99% effective against Aspergillus fumigatus under the UVA irradiation. - Highlights: • PLA composites with titanium oxide (10 nm) were produced by the melting process. • The crystallinity temperature increased ~ 12% when 5 wt.% of TiO{sub 2} was added. • The elastic modulus increased ~ 54% compared to neat PLA. • The PLA/TiO{sub 2} composites showed a reduction of Escherichia coli colonies of 94%. • The PLA/TiO{sub 2} nanocomposites with 8 wt.% were also 99.99% effective against fungi.

  20. Biological H{sub 2} from syngas and from H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, P.; Maness, P.C.; Markov, S.; Martin, S. [National Renewable Energy Lab., Golden, CO (United States)

    1996-10-01

    The two stand-alone objectives of the research are to economically produce neat H{sub 2} in the near term from biomass (thermally gasified to syngas) and in the mid term from H{sub 2}O using cyanobacteria or algae with an oxygen-tolerant bacterial hydrogenase. Photosynthetic bacteria have four different terminal enzymes that mediate their H{sub 2} metabolisms-nitrogenase, uptake hydrogenase, fermentative hydrogenase, and carbon monoxide-linked hydrogenase. Each has been microbiologically and biochemically examined for their potential to specifically generate H{sub 2} in large-scale processes. Based on measurements of maximal activities, stabilities, energy requirements, equilibria, and partial pressures of the H{sub 2} producing reactions, the CO-linked hydrogenase is easily the most suited for practical applications. The enzyme mediates H{sub 2} production from CO at rates up to 1.5 mmol/min/g cell dry weight at near ambient temperature and pressure. Hydrogen can be produced and evolved at linear rates up to at least 2 atmospheres of partial pressure (100% CO). The rate-limiting step with high cell density suspensions is the mass transfer of CO into the aqueous phase. Bioreactor designs have been examined which enhance the mass transfer. Hollow-fiber bioreactors with bacterial cells immobilized on the fiber surfaces evolve H{sub 2} at ambient pressure at rates of about 0.3-0.7 mmol/min/g cdw. One such reactor has been producing H{sub 2} from CO continuously for 9 months with only occasional changes of liquid medium. A trickle-filter reactor with bacteria immobilized on beads removed from a bulk water phase and a pumped-bubble coil reactor with bacteria in suspension are also being examined.

  1. CO{sub 2} applications in Denmark; CO{sub 2}-Anwendungen in Daenemark

    Energy Technology Data Exchange (ETDEWEB)

    Kauffeld, M.; Bertelsen, P.; Hansen, T.M.; Christensen, K.G. [Daenisches Technologisches Inst., Kaelte- und Waermepumpentechnik, Aarhus (Denmark)

    2002-01-01

    Denmark is one of the few countries with special taxes on potent greenhouse gases, e. g. HFC. This incentive makes the application of CO{sub 2} refrigeration systems economically feasible and attractive. Supermarkets, plate freezers, reefer containers and tap water heat pumps are described. First experiences and test results are presented. (orig.) [German] Im vorliegenden Artikel werden CO{sub 2}-Kaelteanlagen, die fuer den Einsatz in Supermaerkten, Gefrieranlagen, Containern und Waermepumpen entwickelt wurden, beschrieben. Betriebserfahrungen und Messergebnisse werden mitgeteilt. (orig.)

  2. TiO{sub 2} doped UO{sub 2} fuels sintered by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Tiankai; Scott, Spencer M.; Xin, Guoqing; Lian, Jie, E-mail: lianj@rpi.edu

    2016-02-15

    UO{sub 2} fuels doped with oxide additives Cr{sub 2}O{sub 3} and TiO{sub 2} display larger grain size, improving fission product retention capability and thus accident tolerance. Spark plasma sintering (SPS) was applied to consolidate TiO{sub 2}-doped UO{sub 2} fuel pellets with 0.5 wt % dopant concentration, above its solubility, in order to induce eutectic phase formation and promote sintering kinetics. The grain size can reach 80 μm by sintering at 1700 °C for 20 min, and liquid U–Ti–O eutectic phase occurs at the triple junction of grain boundaries and significantly improves grain growth during sintering. The oxide additive also impedes the reduction of the initial hyperstoichiometric fuel powders to more stoichiometric fuel pellets upon SPS process. Thermal–mechanical properties of the sintered doped fuel pellets including thermal conductivity and hardness are measured and compared with undoped fuel pellets. The enlarged grain size (80 μm) and densification within short sintering duration highlight the immense possibility of SPS in fabricating large grained UO{sub 2} fuel pellets to improve fuel performance.

  3. Magnetic structure of the magnetocaloric compound AlFe{sub 2}B{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Cedervall, Johan, E-mail: johan.cedervall@kemi.uu.se [Department of Chemistry – Ångström Laboratory, Uppsala University, Box 538, 751 21 Uppsala (Sweden); Andersson, Mikael Svante; Sarkar, Tapati [Department of Engineering Sciences, Uppsala University, Box 534, 751 21 Uppsala (Sweden); Delczeg-Czirjak, Erna K. [Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala (Sweden); Bergqvist, Lars [Department of Materials and Nano Physics and Swedish e-Science Research Centre (SeRC), Royal Institute of Technology (KTH), Electrum 229, SE-164 40 Kista (Sweden); Hansen, Thomas C. [Institut Laue-Langevin, B.P. 156, Grenoble Cedex 9, 38042 France (France); Beran, Premysl [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rez, 25068 Czech Republic (Czech Republic); Nordblad, Per [Department of Engineering Sciences, Uppsala University, Box 534, 751 21 Uppsala (Sweden); Sahlberg, Martin [Department of Chemistry – Ångström Laboratory, Uppsala University, Box 538, 751 21 Uppsala (Sweden)

    2016-04-15

    The crystal and magnetic structures of AlFe{sub 2}B{sub 2} have been studied with a combination of X-ray and neutron diffraction and electronic structure calculations. The magnetic and magnetocaloric properties have been investigated by magnetisation measurements. The samples have been produced using high temperature synthesis and subsequent heat treatments. The compound crystallises in the orthorhombic crystal system Cmmm and it orders ferromagnetically at 285 K through a second order phase transition. At temperatures below the magnetic transition the magnetic moments align along the crystallographic a-axis. The magnetic entropy change from 0 to 800 kA/m was found to be −1.3 J/K kg at the magnetic transition temperature. - Graphical abstract: The magnetic structure of AlFe{sub 2}B{sub 2} has been investigated using neutron diffraction and the magnetic spins have been found to align ferromagnetically along the crystallographic a-axis. - Highlights: • The crystal and magnetic structures of AlFe{sub 2}B{sub 2} have been studied. • Orders ferromagnetically at 285 K via a second order phase transition. • The magnetic moments are found to be aligned along the crystallographic a-axis. • The magnetic entropy change from 0 to 800 kA/m was found to be −1.3 J/K kg.

  4. Potential energy surface of triplet N{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Varga, Zoltan; Meana-Pañeda, Rubén; Song, Guoliang; Paukku, Yuliya; Truhlar, Donald G., E-mail: truhlar@umn.edu [Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431 (United States)

    2016-01-14

    We present a global ground-state triplet potential energy surface for the N{sub 2}O{sub 2} system that is suitable for treating high-energy vibrational-rotational energy transfer and collision-induced dissociation. The surface is based on multi-state complete-active-space second-order perturbation theory/minimally augmented correlation-consistent polarized valence triple-zeta electronic structure calculations plus dynamically scaled external correlation. In the multireference calculations, the active space has 14 electrons in 12 orbitals. The calculations cover nine arrangements corresponding to dissociative diatom-diatom collisions of N{sub 2}, O{sub 2}, and nitric oxide (NO), the interaction of a triatomic molecule (N{sub 2}O and NO{sub 2}) with the fourth atom, and the interaction of a diatomic molecule with a single atom (i.e., the triatomic subsystems). The global ground-state potential energy surface was obtained by fitting the many-body interaction to 54 889 electronic structure data points with a fitting function that is a permutationally invariant polynomial in terms of bond-order functions of the six interatomic distances.

  5. International trade and CO{sub 2} emissions; International handel og CO{sub 2}-udledning

    Energy Technology Data Exchange (ETDEWEB)

    Munksgaard, J.; Pade, L.L. [AKF, Copenhagen (Denmark); Lenzen, M. [Univ. of Sydney (Australia)

    2005-04-01

    International trade has an impact on national CO{sub 2} emissions and consequently on the ability to fulfil national CO{sub 2} reduction targets. Through goods and services traded in a globally interdependent world, the consumption in each country is linked to greenhouse gas emissions in other countries. It has been argued that in order to achieve equitable reduction targets, international trade has to be taken into account when assessing nations' responsibility for abating climate change. Especially for open economies such as Denmark, greenhouse gases embodied in international traded commodities can have a considerable influence on the national greenhouse gas responsibility. Founded in the concepts of 'producer CO{sub 2} responsibility', 'consumer CO{sub 2} responsibility' and 'CO{sub 2} trade balance' the aim of the present study has been to develop the single-region input-output model as used in a previous study into a multi-region input-output model in order to get a more realistic description of the production technologies actually used in the countries of imports. The study concludes that trade is the key to define CO{sub 2} responsibility on macroeconomics level and that imports should be founded in a multi-region model approach. The study also points at the need to consider the impact from foreign trade when negotiating national reduction targets and base line scenarios within the context of international climate agreements. (BA)

  6. Dynamic magnetic order in CeCu{sub 2}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Stockert, O.; Arndt, J.; Jeevan, H.S.; Geibel, C.; Steglich, F. [Max-Planck-Institut CPfS, Dresden (Germany); Faulhaber, E. [Institut fuer Festkoerperphysik, TU Dresden, Dresden (Germany); Fouquet, P. [Institut Laue-Langevin, Grenoble (France)

    2008-07-01

    The heavy-fermion compound CeCu{sub 2}Si{sub 2} attracts still considerable interest due to the competition between antiferromagnetic order and superconductivity. The nature of the magnetic order is an incommensurate spin-density wave below T{sub N}{approx}800 mK determined by the nesting properties of the Fermi surface. Recently we observed that the magnetic Bragg peaks in only magnetically ordered CeCu{sub 2}Si{sub 2} are broadened in q space. Starting from long-range order the magnetic Bragg peaks broaden below T{approx}550 mK. At T=100 mK a correlation length {xi}{approx}130A has been estimated. From this finite correlation length/domain size at lowest temperature a finite lifetime of the magnetic peaks was expected. However, in neutron scattering experiments using a triple-axis spectrometer no broadening in energy was observed. Hence, the neutron spin-echo technique was chosen for this investigation due to the higher energy resolution. Data were recorded at different temperatures below T{sub N}. From the spin-echo spectra some dynamic nature of the magnetic order in only magnetically ordered CeCu{sub 2}Si{sub 2} can be inferred. The fluctuation rate of the antiferromagnetic order is estimated to be in the order of 50 MHz at lowest temperatures. Our results are discussed in comparison to other measurements.

  7. Control of murine macrophage H/sub 2/O/sub 2/ metabolism by amphotericin B

    Energy Technology Data Exchange (ETDEWEB)

    Stein, S.H.; Wolf, J.E.; Little, J.R.

    1986-03-05

    The authors investigated the ability of amphotericin B (AmB) to modulate H/sub 2/O/sub 2/ metabolism in murine macrophages (M theta). Following a single 0.5 mg intraperitoneal dose of AmB, AKR peritoneal M theta showed greater chemiluminescence (CL) after triggering with phorbol myristate acetate (PMA) than C57BL/6 M theta. The capacity for enhanced M theta CL was sustained for at least 2 weeks after AmB injection in AKR mice but less in C57BL/6 M theta. In other experiments, intracellular H/sub 2/O/sub 2/ metabolism was evaluated by a fluorescence activated cell sorting (FACS) assay described by Bass et al. A comparison of FACS histograms of peritoneal M theta from AmB treated and control AKR mice revealed 25-28% stimulation in the experimental group; M theta from AmB treated C57BL/6 mice showed a significant reduction of the H/sub 2/O/sub 2/ metabolism compared with resident M theta. These results are in accord with the effects of AmB on survival from experimental infection with Listeria monocytogenes. AmB enhanced survival in AKR mice while it reduced the survival of C57BL/6 mice infected with this facultative intracellular bacterium. Thus, AmB-induced resistance to infection correlates with stimulation of the M theta respiratory burst.

  8. Absorption cross sections for water, ammonia, methane, neopentane, the chloromethanes, and CF<sub>2<sub>2Cl<sub>2

    Energy Technology Data Exchange (ETDEWEB)

    Person, James C. [Argonne National Lab., IL (United States); Fowler, David E. [Macalester College, St. Paul, MN (United States); Nicole, Paul P. [Argonne National Lab., IL (United States)

    1975-12-01

    Experimental data on the absorption cross section (or differential oscillator strength) are presented for water, ammonia, methane, neopentane, CH3Cl, CH<sub>2Cl<sub>2, CHCl3, CCl4, and CF<sub>2Cl<sub>2. In all cases the upper energy limit is 21.2 eV, and the lower energy limit is between 11 and 13 eV.

  9. Crystallization and magnetic properties of a 10Li{sub 2}O–9MnO{sub 2}–16Fe{sub 2}O{sub 3}–25CaO–5P{sub 2}O{sub 5}–35SiO{sub 2} glass

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Moo-Chin, E-mail: mcwang@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan (China); Cheng, Huy-Zu [Department of Materials Science and Engineering, I-Shou University, 1 123456789Hsueh-Cheng Road, Section 1, Ta-Hsu, Kaohsiung 84001, Taiwan (China); Lin, Huey-Jiuan [Department of Materials Science and Engineering, National United University, 1 Lien-Da Road, Kung-Ching Li, Miao-Li 36003, Taiwan (China); Wang, Chien-Fu [Department of Materials Science and Engineering, I-Shou University, 1 123456789Hsueh-Cheng Road, Section 1, Ta-Hsu, Kaohsiung 84001, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.tw [Department of Materials Science and Engineering, National United University, 1 Lien-Da Road, Kung-Ching Li, Miao-Li 36003, Taiwan (China)

    2013-06-15

    The crystallization behavior and magnetic properties of 10Li{sub 2}O–9MnO{sub 2}–16Fe{sub 2}O{sub 3}–25CaO–5P{sub 2}O{sub 5}–35SiO{sub 2} (10LFS) glass have been studied using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) to observe the crystallization behavior and a superconducting quantum interference device (SQUID) for measurements of the magnetic properties. The DTA shows that the 10LFS glass has one broad exothermic peak at approximately 674 °C and one sharp (the highest) exothermic peak at 764 °C. When the 10LFS glass crystallized at 850 °C for 4 h, the crystalline phases identified by XRD were lithium silicate (Li{sub 2}SiO{sub 3}), β-wollastonite (β-CaSiO{sub 3}), lithium orthophosphate (Li{sub 3}PO{sub 4}), magnetite (FeFe{sub 2}O{sub 4}) and triphylite (Li(Mn{sub 0.5}Fe{sub 0.5})PO{sub 4}). The SEM surface analysis revealed that the β-wollastonite and lithium silicate have a lath morphology. The TEM microstructure examination showed that the largest FeFe{sub 2}O{sub 3} particles have a size of approximately 0.3 μm. When the 10LFS glass was heat treated at 850 °C for 16 h and a magnetic field of 1000 Oe was applied, a very small remnant magnetic induction of 0.01 emu g{sup −1} and a coercive force of 50 Oe were obtained, which revealed an inverse spinel structure. - Highlights: ► The phases formed at 850 °C in the 10LFS glass-ceramics are LiSiO{sub 3}, β-CaSiO{sub 3}, Li{sub 3}PO{sub 4}, FeFe{sub 2}O{sub 4} and Li(Mn{sub 0.5}Fe{sub 0.5})PO{sub 4}. ► The β-wollastonite and lithium silicate have a lath morphology. ► When 10LFS glass-ceramics applied magnetic field showing the ferromagnetic behavior of an inverse spinel structure.

  10. Topologically identical, but geometrically isomeric layers in hydrous α-, β-Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O and anhydrous Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Na; Klepov, Vladislav V. [Forschungszentrum Jülich GmbH, Institute for Energy and Climate Research (IEK-6), 52428 Jülich (Germany); Villa, Eric M. [Department of Chemistry, Creighton University, 2500 California Plaza, Omaha NE 68178 (United States); Bosbach, Dirk [Forschungszentrum Jülich GmbH, Institute for Energy and Climate Research (IEK-6), 52428 Jülich (Germany); Suleimanov, Evgeny V. [Department of Chemistry, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod (Russian Federation); Depmeier, Wulf [Institut für Geowissenschaften, Universität zu Kiel, 24118 Kiel (Germany); Albrecht-Schmitt, Thomas E., E-mail: albrecht-schmitt@chem.fsu.edu [Department of Chemistry and Biochemistry, Florida State University, 102 Varsity Way, Tallahassee, FL 32306-4390 (United States); Alekseev, Evgeny V., E-mail: e.alekseev@fz-juelich.de [Forschungszentrum Jülich GmbH, Institute for Energy and Climate Research (IEK-6), 52428 Jülich (Germany); Institut für Kristallographie, RWTH Aachen University, 52066 Aachen (Germany)

    2014-07-01

    The hydrothermal reaction of uranyl nitrate with rubidium nitrate and arsenic (III) oxide results in the formation of polymorphic α- and β-Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O (α-, β-RbUAs) and the anhydrous phase Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})] (RbUAs). These phases were structurally, chemically and spectroscopically characterized. The structures of all three compounds are based upon topologically identical, but geometrically isomeric layers. The layers are linked with each other by means of the Rb cations and hydrogen bonding. Dehydration experiments demonstrate that water deintercalation from hydrous α- and β-RbUAs yields anhydrous RbUAs via topotactic reactions. - Graphical abstract: Three different layer geometries observed in the structures of Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})] and α- and β- Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O. Two different coordination environments of uranium polyhedra (types I and II) are shown schematically on the top of the figure. - Highlights: • Three new uranyl arsenates were synthesized from the hydrothermal reactions. • The phases consist of the topologically identical but geometrically different layers. • Topotactic transitions were observed in the processes of mono-hyrates dehydration.

  11. Preparation of Ag@mSiO{sub 2} and Pt@mSiO{sub 2}nano composites using trioctylmethyl ammonium hydrogen phthalate (TOMAHP) ionic liquid as reaction medium

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Sujoy, E-mail: sujoyb@barc.gov.in [Chemical Engineering Group, Bhabha Atomic Research Centre, Mumbai 400085 (India); Dasgupta, Kinshuk [Materials Group, Bhabha Atomic Research Centre, Mumbai 400085 (India); Bahadur, Jitendra [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tewari, Raghavendra [Materials Group, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mazumder, Subhasish [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2016-09-15

    A novel one step green chemistry approach utilizing trioctylmethyl ammonium hydrogen phthalate (TOMAHP), task specific ionic liquid has been attempted for synthesis of Ag and Pt nanoparticles supported on silica (Ag@mSiO{sub 2} and Pt@mSiO{sub 2}). Structure, size distribution and morphology of these nano-composite particles were evaluated using X-ray diffraction (XRD), transmission electron microscopy (TEM), small angle neutron scattering (SANS) as well as small angle X-ray scattering (SAXS) techniques. The XRD results show that Ag/Pt metal nanoparticles deposited on to SiO{sub 2} surface are face center cubic (fcc) in nature. The TEM and SAXS/SANS results show the morphology and size distributions of Ag and Pt nanoparticles loaded on to the surface of SiO{sub 2}. It has been found that Ag nanoparticles are well dispersed on to the SiO{sub 2} surface and are quite monodisperse in size, whereas Pt nanoparticles are quite polydisperse in size and forms aggregate or chain like structure on SiO{sub 2} surface containing primary nanoparticles of typical size range 3–7 nm. The stability of nanoparticles, which controls its dispersion on SiO{sub 2} substrate, has been discussed. - Graphical abstract: Mechanism for Ag@mSiO{sub 2} and Pt@mSiO{sub 2} nano composites in TOMAHP ionic liquid medium. - Highlights: • Novel methods for preparation of Pt@SiO{sub 2} and Ag@SiO{sub 2} nano composite in functionalized ionic liquid. • Pt@SiO{sub 2} and Ag@SiO{sub 2} nano composite are characterized using XRD, TEM as well as small angle x-ray scattering techniques. • The sizes of nano composite is <10 nm in size. • The method is simple one step, green chemical reduction method to prepare SiO{sub 2} support nano catalyst.

  12. Surfactant-assisted preparation of core-shell-type TiO{sub 2}–Fe{sub 2}O{sub 3} composites and their photocatalytic activities under room light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Inseok; You, Kyoung-Eun; Kim, Young Chai; Oh, Seong-Geun, E-mail: seongoh@hanyang.ac.kr

    2014-10-15

    Graphical abstract: - Highlights: • TiO{sub 2}–Fe{sub 2}O{sub 3} composites having core-shell structure were synthesized in cationic surfactant solution. • Thickness of Fe{sub 2}O{sub 3} shell was controlled by varying the concentration Fe salt. • Composites exhibited high performance of MB photodegradation under room light irradiation. • Higher catalytic activities were attributed to band edge shift and decrease of recombination. - Abstract: TiO{sub 2}–Fe{sub 2}O{sub 3} composites of core-shell structure were synthesized by using surfactant-assisted preparation method. The shell on TiO{sub 2} surface was composed of small Fe{sub 2}O{sub 3} nanoparticles with an average diameter of 12 nm. The thickness of Fe{sub 2}O{sub 3} shell was controlled by varying the concentration of Fe salt and using CTAB as the surfactant and binder. After annealing at 450 °C, the crystal structures of composites were found to be anatase and hematite mixed phase. Composites showed the ferromagnetic property which is favorable in water treatment. The characteristics of composites were analyzed by using TEM, EDS, XRD, XPS, VSM and PL. As an application of TiO{sub 2}–Fe{sub 2}O{sub 3} composites in water treatment, their catalytic performances for the degradation of methylene blue (MB) were examined by using UV–Vis spectrophotometer under room light irradiation. TiO{sub 2}–Fe{sub 2}O{sub 3} composites prepared with CTAB exhibited high performance of MB photodegradation because of the effects of band edge shift and decrease of recombination attributed to the formation of Fe{sub 2}O{sub 3} particles on TiO{sub 2} surface.

  13. 4,6-Dimethyl-dibenzothiophene conversion over Al{sub 2}O{sub 3}-TiO{sub 2}-supported noble metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, Sara [Departamento de Ingenieria de Procesos e Hidraulica, Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Vicentina, Iztapalapa, 09340, Mexico, D.F. (Mexico); Escobar, Jose, E-mail: jeaguila@imp.mx [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, San Bartolo Atepehuacan, Gustavo A. Madero, 07730, Mexico, D.F. (Mexico); Vazquez, Armando; Reyes, Jose Antonio de los [Departamento de Ingenieria de Procesos e Hidraulica, Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Vicentina, Iztapalapa, 09340, Mexico, D.F. (Mexico); Hernandez-Barrera, Melissa [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, San Bartolo Atepehuacan, Gustavo A. Madero, 07730, Mexico, D.F. (Mexico)

    2011-03-15

    Research highlights: {yields} Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-TiO{sub 2} (molar ratio Al/Ti = 2, AT2) mixed oxides were pore-filling impregnated to obtain Pd, Pt and Pd-Pt catalysts with {approx}1 wt% nominal metal loading. {yields} Reduced catalysts were tested in the 4,6-dimethyl-dibenzothiophene hydrodesulfurization (HDS). {yields} In Pd-containing materials, TiO{sub 2} incorporation into the alumina support was favorable to the catalytic activity of noble metal catalysts. {yields} Enhanced intrinsic activity (per exposed metallic site) was obtained in Pt-containing catalysts supported on the AT2 mixed oxide. {yields} Yield to different products over various catalysts seemed to be strongly influenced by metallic particles dispersion. - Abstract: Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-TiO{sub 2} (molar ratio Al/Ti = 2, AT2) mixed oxides were synthesized using a low-temperature sol-gel method and were further pore-filling impregnated to obtain Pd and Pt catalysts with {approx}1 wt% nominal metal loading. Simultaneous impregnation was used to prepare bimetallic materials at Pd:Pt = 80:20. Solids characterization was carried out by N{sub 2}-physisorption, high-resolution transmission electron microscopy (HR-TEM and E-FTEM), X-ray diffraction, temperature-programmed reduction and CO-chemisorption. Reduced (350 deg. C, H{sub 2} flow) catalysts were tested in the 4,6-dimethyl-dibenzothiophene hydrodesulfurization (HDS) (in n-dodecane, at 300 deg. C and 5.5 MPa, batch reactor). In Pd-containing materials, TiO{sub 2} incorporation into the alumina support was favorable to the catalytic activity of noble metal catalysts, where bimetallic Pd-Pt with AT2 carrier had the highest organo-S compound conversion. Enhanced intrinsic activity (per exposed metallic site) was obtained in Pt-containing catalysts supported on the AT2 mixed oxide (as compared to alumina-supported ones). Yield to different products over various catalysts seemed to be strongly influenced by

  14. SnO{sub 2} foam grain-shaped nanoparticles: Synthesis, characterization and UVA light induced photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Abdelkader, Elaziouti, E-mail: elaziouti_a@yahoo.com [Laboratory of Electronic Microscope and Materials Science, University of Science and Technology of Oran (USTO M. B), BP 1505 El M' naouar, 31000 Oran (Algeria); Nadjia, Laouedj, E-mail: nlaouedj@yahoo.fr [Laboratory of Inorganic Materials Chemistry and Application, University of Science and Technology of Oran (USTO M. B), BP 1505 El M' naouar, 31000 Oran (Algeria); Naceur, Benhadria, E-mail: nacer1974@yahoo.fr [Laboratory of Inorganic Materials Chemistry and Application, University of Science and Technology of Oran (USTO M. B), BP 1505 El M' naouar, 31000 Oran (Algeria); Noureddine, Bettahar, E-mail: nbettahar2001@yahoo.fr [Laboratory of Inorganic Materials Chemistry and Application, University of Science and Technology of Oran (USTO M. B), BP 1505 El M' naouar, 31000 Oran (Algeria)

    2016-09-15

    Cassiterite (tin oxide; SnO{sub 2}) nanoparticles (NPs), has been successfully synthesized via a sol-gel method. The obtained compounds are subsequently calcined at 80, 450 and 650 °C for 4 h and are assigned as SnO{sub 2}-80, SnO{sub 2}-450 NPs and SnO{sub 2}-650 NPs, respectively. All prepared samples were characterized using thermogravimetric analysis coupled with mass spectroscopy (TG-SM), X-ray diffraction (XRD), scanning electron microscope (SEM) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). The XRD results confirmed the aggregated cassiterite SnO{sub 2} nanoparticles (NPs) with a size ranging from 13 to 23 nm. The absorption edge of the SnO{sub 2} NPs samples calcined at higher temperatures showed 25 nm (SnO{sub 2}-450 NPs) and 10 nm (SnO{sub 2}-650 NPs) red shifted compared with that of commercial SnO{sub 2}-com NPs sample. The photodegradation efficiency of SnO{sub 2} NPs was investigated using Congo red (CR) dye, as model organic pollutant. The effect of environmental factors (e.g., reaction time and calcination temperature) on the photocatalysis process of CR on SnO{sub 2} NPs was investigated in photocatalysis process under UVA light irradiation. We found that the SnO{sub 2}-650 NPs with 23 nm particle size and about 3.49 eV band gap was higher than that of the SnO{sub 2}-450 as well as the commercial SnO{sub 2}-com NPs. Pseudo-first-order kinetic model gave the best fit, with highest correlation coefficients (R{sup 2} ≥ 0.95). On the basis of the energy band diagram positions, the enhanced photodegradation efficiency SnO{sub 2} NPs catalyst could be proceeded via direct reactions with (O{sub 2}·{sup -} and ·OH), as active oxidative species involved in the photocatalysis process of CR dye under UVA-light irradiation. - Highlights: • SnO{sub 2} NPs photocatalysts were synthesized using a facile sol–gel route. • As-prepared SnO{sub 2} NPs were characterized by XRD, SEM and UV–vis-DRS techniques. • Noticeably UVA

  15. Phase relations in the ZrO{sub 2}-Sm{sub 2}O{sub 3}-Y{sub 2}O{sub 3}-Al{sub 2}O{sub 3} system. Experimental investigation and thermodynamic modelling

    Energy Technology Data Exchange (ETDEWEB)

    Fabrichnaya, Olga; Savinykh, Galina; Zienert, Tilo; Schreiber, Gerhard [Technical Univ. of Freiberg (Germany). Inst. of Materials Science; Seifert, Hans J. [Technical Univ. of Freiberg (Germany). Inst. of Materials Science; Karlsruhe Institute of Technology (Germany). Inst. of Applied Physics

    2012-12-15

    Sub-solidus phase relations in the ZrO{sub 2}-Sm{sub 2}O{sub 3}-Y{sub 2}O{sub 3} and Sm{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-Y{sub 2}O{sub 3} systems were experimentally studied at 1523-1873K and thermodynamic databases for these systems were developed. Analysis of phase equilibria in the Sm{sub 2}O{sub 3}-Y{sub 2}O{sub 3}-Al{sub 2}O{sub 3} system indicated that REAM phase (Sm,Y){sub 4}Al{sub 2}O{sub 9} is not stable in the Sm{sub 2}O{sub 3} rich-composition. Therefore, the stability limit of the Sm{sub 4}Al{sub 2}O{sub 9} phase was established experimentally and thermodynamic parameters of the Sm{sub 2}O{sub 3}-Al{sub 2}O{sub 3} system were re-optimised. The eutectic melting in the Sm{sub 2}O{sub 3}-Y{sub 2}O{sub 3}-Al{sub 2}O{sub 3} system was investigated using differential thermal analysis and scanning electron microscopy. The results obtained were used to assess the mixing parameter of the liquid phase. A new description of binary system was introduced into the database of the ZrO{sub 2}-Sm{sub 2}O{sub 3}-Al{sub 2}O{sub 3} system and phase diagrams were re-calculated. The obtained thermodynamic databases were combined with literature data for the ZrO{sub 2}-Y{sub 2}O{sub 3}-Al{sub 2}O{sub 3} system and a thermodynamic database for the ZrO{sub 2}-Sm{sub 2}O{sub 3}-Y{sub 2}O{sub 3}-Al{sub 2}O{sub 3} system was developed. (orig.)

  16. Synthesis and characterization of magnetic diphase ZnFe{sub 2}O{sub 4}/{gamma}-Fe{sub 2}O{sub 3} electrospun fibers

    Energy Technology Data Exchange (ETDEWEB)

    Arias, M. [Department of Physics-Mathematics, University of Puerto Rico at Cayey, 205 Avenue Antonio R. Barcelo, Cayey 00736 (Puerto Rico); Instituto Tecnologico de Santo Domingo (INTEC), Avenida de Los Proceres, Gala, P.O. Box 342-9 and 249-2, Santo Domingo (Dominican Republic); Pantojas, V.M., E-mail: victor.pantojas@upr.edu [Department of Physics-Mathematics, University of Puerto Rico at Cayey, 205 Avenue Antonio R. Barcelo, Cayey 00736 (Puerto Rico); Perales, O. [Department of Engineering Science and Materials, University of Puerto Rico at Mayagueez, Mayagueez 00680-9044 (Puerto Rico); Institute for Functional Nanomaterials, University of Puerto Rico, San Juan 00936 (Puerto Rico); Otano, W. [Department of Physics-Mathematics, University of Puerto Rico at Cayey, 205 Avenue Antonio R. Barcelo, Cayey 00736 (Puerto Rico); Institute for Functional Nanomaterials, University of Puerto Rico, San Juan 00936 (Puerto Rico)

    2011-08-15

    Magnetic nanofibers of ZnFe{sub 2}O{sub 4}/{gamma}-Fe{sub 2}O{sub 3} composite were synthesized by electrospinning from a sol-gel solution containing a molar ratio (Fe/Zn) of 3. The effects of the calcination temperature on phase composition, particle size and magnetic properties have been investigated. Zinc ferrite fibers were obtained by calcinating the electrospun fibers in air from 300 to 800 deg. C and characterized by thermogravimetric analyses, Fourier transformed infrared spectroscopy, X-ray photoemission spectroscopy, X-ray diffraction, vibration sample magnetometry and magnetic force microscopy. The resulting fibers, with diameters ranging from 90 to 150 nm, were ferrimagnetic with high saturation magnetization as compared to bulk. An increase in the calcination temperature resulted in an increase in particle size and saturation magnetization. The observed increase in saturation magnetization was most likely due to the formation and growth of ZnFe{sub 2}O{sub 4}/{gamma}-Fe{sub 2}O{sub 3} diphase crystals. The highest saturation magnetization (45 emu/g) was obtained for fibers calcined at 800 deg. C. - Research Highlights: > Nanofibers were produced by electrospinning from a sol-gel. > ZnFe{sub 2}O{sub 4}/{gamma}-Fe{sub 2}O{sub 3} formed after cacination in air from 300 to 800 deg. C. > Fibers were ferrimagnetic with high saturation magnetization. > Crystallite particle size and saturation magnetization increase with temperature. > Magnetic domains with sizes similar to topographical grains were observed.

  17. Surface modification and enhanced photocatalytic CO{sub 2} reduction performance of TiO{sub 2}: a review

    Energy Technology Data Exchange (ETDEWEB)

    Low, Jingxiang; Cheng, Bei [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070 (China); Yu, Jiaguo, E-mail: jiaguoyu@yahoo.com [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070 (China); Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2017-01-15

    Highlights: • Application of modified TiO{sub 2} for photocatalytic CO{sub 2} reduction is summarized. • Different surface modification strategies of TiO{sub 2} are highlighted. • Summary and future perspectives in photocatalytic CO{sub 2} reduction are presented. - Abstract: Recently, the excessive consumption of fossil fuels has caused high emissions of the greenhouse gases, CO{sub 2} into atmosphere and global energy crisis. Mimicking the natural photosynthesis by using semiconductor materials to achieve photocatalytic CO{sub 2} reduction into valuable solar fuels such as CH{sub 4}, HCO{sub 2}H, CH{sub 2}O, and CH{sub 3}OH is known as one of the best solutions for addressing the aforementioned issue. Among various proposed photocatalysts, TiO{sub 2} has been extensively studied over the past several decades for photocatalytic CO{sub 2} reduction because of its cheapness and environmental friendliness. Particularly, surface modification of TiO{sub 2} has attracted numerous interests due to its capability of enhancing the light absorption ability, facilitating the electron-hole separation, tuning the CO{sub 2} reduction selectivity and increasing the CO{sub 2} adsorption and activation ability of TiO{sub 2} for photocatalytic CO{sub 2} reduction. In this review, recent approaches of the surface modification of TiO{sub 2} for photocatalytic CO{sub 2} reduction, including impurity doping, metal deposition, alkali modification, heterojunction construction and carbon-based material loading, are presented. The photocatalytic CO{sub 2} reduction mechanism and pathways of TiO{sub 2} are discussed. The future research direction and perspective of photocatalytic CO{sub 2} reduction over surface-modified TiO{sub 2} are also presented.

  18. Morphology transformation of Cu{sub 2}O by adding TEOA and their antibacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Weijia; Zheng, Min, E-mail: zhengmin@suda.edu.cn; Li, Rong; Wang, Yuyuan [Soochow University, National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering (China)

    2016-11-15

    Cu{sub 2}O polyhedral particles and hollow spheres were successfully synthesized by adjusting the concentration of triethanolamine (TEOA). The as-prepared samples were structurally characterized by the scanning electron microscope (SEM), X-ray powder diffraction (XRD), and transmission electron microscopy (TEM). The results revealed that the solid polyhedral Cu{sub 2}O with sizes ranging from 70 to 150 nm was in good crystallization. The diameter of the hollow Cu{sub 2}O spheres increased to 350–450 nm. It was found that the sizes and morphologies of the products could be significantly affected by the concentration of TEOA. And the morphology of Cu{sub 2}O transformed from solid polyhedrons to hollow spheres with the further enrichment of TEOA concentration. A possible mechanism was proposed to explain the formation of the hollow Cu{sub 2}O spheres. In addition, we investigated the antibacterial activities of the samples. It was demonstrated that the hollow Cu{sub 2}O sphere exhibited better antibacterial activities for Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) compared with the solid polyhedral Cu{sub 2}O.

  19. A rechargeable Li-CO{sub 2} battery with a gel polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chao; Guo, Ziyang; Yang, Bingchang; Liu, Yao; Wang, Yonggang; Xia, Yongyao [Dept. of Chemistry and Shanghai Key Lab. of Molecular Catalysis and Innovative Materials, Inst. of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan Univ. (China)

    2017-07-24

    The utilization of CO{sub 2} in Li-CO{sub 2} batteries is attracting extensive attention. However, the poor rechargeability and low applied current density have remained the Achilles' heel of this energy device. The gel polymer electrolyte (GPE), which is composed of a polymer matrix filled with tetraglyme-based liquid electrolyte, was used to fabricate a rechargeable Li-CO{sub 2} battery with a carbon nanotube-based gas electrode. The discharge product of Li{sub 2}CO{sub 3} formed in the GPE-based Li-CO{sub 2} battery exhibits a particle-shaped morphology with poor crystallinity, which is different from the contiguous polymer-like and crystalline discharge product in conventional Li-CO{sub 2} battery using a liquid electrolyte. Accordingly, the GPE-based battery shows much improved electrochemical performance. The achieved cycle life (60 cycles) and rate capability (maximum applied current density of 500 mA g{sup -1}) are much higher than most of previous reports, which points a new way to develop high-performance Li-CO{sub 2} batteries. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Bifunctional bridging linker-assisted synthesis and characterization of TiO{sub 2}/Au nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Žunič, Vojka, E-mail: vojka.zunic@ijs.si, E-mail: vojka13@gmail.com; Kurtjak, Mario; Suvorov, Danilo [Jožef Stefan Institute, Advanced Materials Department (Slovenia)

    2016-11-15

    Using a simple organic bifunctional bridging linker, titanium dioxide (TiO{sub 2}) nanoparticles were coupled with the Au nanoparticles to form TiO{sub 2}/Au nanocomposites with a variety of Au loadings. This organic bifunctional linker, meso-2,3-dimercaptosuccinic acid, contains two types of functional groups: (i) the carboxyl group, which enables binding to the TiO{sub 2}, and (ii) the thiol group, which enables binding to the Au. In addition, the organic bifunctional linker acts as a stabilizing agent to prevent the agglomeration and growth of the Au particles, resulting in the formation of highly dispersed Au nanoparticles. To form the TiO{sub 2}/Au nanocomposites in a simple way, we deliberately applied a synthetic method that simultaneously ensures: (i) the capping of the Au nanoparticles and (ii) the binding of different amounts of Au to the TiO{sub 2}. The TiO{sub 2}/Au nanocomposites formed with this method show enhanced UV and Vis photocatalytic activities when compared to the pure TiO{sub 2} nanopowders.Graphical Abstract.

  1. ALD Produced B{sub 2}O{sub 3}, Al{sub 2}O{sub 3} and TiO{sub 2} Coatings on Gd{sub 2}O{sub 3} Burnable Poison Nanoparticles and Carbonaceous TRISO Coating Layers

    Energy Technology Data Exchange (ETDEWEB)

    Weimer, Alan

    2012-11-26

    This project will demonstrate the feasibility of using atomic layer deposition (ALD) to apply ultrathin neutron-absorbing, corrosion-resistant layers consisting of ceramics, metals, or combinations thereof, on particles for enhanced nuclear fuel pellets. Current pellet coating technology utilizes chemical vapor deposition (CVD) in a fluidized bed reactor to deposit thick, porous layers of C (or PyC) and SiC. These graphitic/carbide materials degrade over time owing to fission product bombardment, active oxidation, thermal management issues, and long-term irradiation effects. ALD can be used to deposit potential ceramic barrier materials of interest, including ZrO{sub 2}, Y{sub 2}O{sub 3}:ZrO{sub 2} (YSZ), Al{sub 2}O{sub 3}, and TiO{sub 2}, or neutron-absorbing materials, namely B (in BN or B{sub 2}O{sub 3}) and Gd (in Gd{sub 2}O{sub 3}). This project consists of a two-pronged approach to integrate ALD into the next-generation nuclear plant (NGNP) fuel pellet manufacturing process:

  2. Properties of lithium disilicate reinforced with ZrO{sub 2} (3mol%Y{sub 2}O{sub 3}; Propriedades de dissilicato de litio reforcado com ZrO{sub 2} (3mol%Y{sub 2}O{sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    Alves, M.F.R.P.; Cossu, C.M.F.A.; Santos, C., E-mail: manuelfellipealves@gmail.com [Universidade do Estado do Rio de Janeiro (UERJ), Resende, RJ (Brazil). Faculdade de Tecnologia; Silva, C.L.M. [Centro Universitario de Volta Redonda (UniFOA), Volta Redonda, RJ (Brazil); Simba, B.G. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Guaratingueta, SP (Brazil). Faculdade de Engenharia; Fernandes, M.H.F. [Universidade de Aveiro (Portugal)

    2016-07-01

    The new generation of dental ceramics based on lithium disilicate, Li{sub 2}Si{sub 2}O{sub 5}, allows the production of restorative prosthetic with reduced times compared to alumina and / or zirconia (Y-TZP). A great limitation of their use is related low fracture strength of such glass-ceramics, which reduces their use in unit fixed prosthesis. In this work, lithium disilicate reinforced with 10% ZrO{sub 2} (3-mol% Y{sub 2}O{sub 3}) is characterized by relative density, crystalline phase, hardness, fracture toughness and microstructural aspects. Lithium metasilicate and tetragonal zirconia, prior to heat treatment. After thermal treatment under vacuum at 840 deg C-8min the lithium metasilicate is converted to lithium disilicate as the ZrO{sub 2} phase remains in the tetragonal structure. This maintenance of the tetragonal phase ensures the material a good fracture toughness, reaching average values near 2MPam{sup 1/2}, while the average hardness of 600HV. Morphological analysis of the samples indicates that ZrO{sub 2} particles are uniformly dispersed in the matrix composed of high aspect ratio lithium disilicate grains, which contributes to the results presented.. A critical analysis of the performance of toughening mechanisms such as cracks deflection, phase transformation of ZrO{sub 2} (T-M), residual stress between the matrix and the reinforcement are presented, discussed and compared with other ceramic materials used in dentistry restorer. (author)

  3. Thermoresponsive behaviour of AM sub 2 O sub 8 materials

    CERN Document Server

    Allen, S

    2003-01-01

    This thesis investigates the synthesis and structural characterisation of AM sub 2 O sub 8 phases, many of which show negative thermal expansion (NTE); relevant literature is reviewed in Chapter One. Chapter Two describes the synthesis, structure solution, and mechanistic role of a new family of low-temperature (LT) orthorhombic AM sub 2 O sub 8 polymorphs (A sup I sup V = Zr, Hf; M sup V sup I = Mo, W). These materials are key intermediates in the preparation of cubic AM sub 2 O sub 8 phases from AM sub 2 O sub 7 (OH) sub 2 (H sub 2 O) sub 2. The structure of LT-AM sub 2 O sub 8 has been elucidated by combined laboratory X-ray and neutron powder diffraction. Variable temperature X-ray diffraction (VTXRD) studies have shown LT-AMo sub 2 O sub 8 phases exhibit anisotropic NTE. LT-ZrMo sub 2 O sub 8 has been shown to undergo spontaneous rehydration, allowing preparation of ZrMo sub 2 O sub 7 (OD) sub 2 (D sub 2 O) sub 2 and assignment of D sub 2 O/OD positions within the structure by neutron diffraction. Using ...

  4. Microwave-induced crystallization of AC/TiO{sub 2} for improving the performance of rhodamine B dye degradation

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Fei [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Wu, Zhansheng, E-mail: wuzhans@126.com [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Chen, Qiuyu; Yan, Yujun [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Cravotto, Giancarlo; Wu, Zhilin [Dipartimento di Scienza e Tecnologia del Farmaco, University of Turin, Torino 10125 (Italy)

    2015-10-01

    Graphical abstract: - Highlights: • Mixed phase titania coated with AC was obtained by microwave irradiation method. • The TiO{sub 2} nanoparticles were spherical and well distributed on the surface of AC. • The light absorption edges of AC/TiO{sub 2} showed red-shift compared to the pure TiO{sub 2}. • Higher surface and TiO{sub 2} content of AC/TiO{sub 2} could improve photocatalytic efficiency. - Abstract: Titanium dioxide (TiO{sub 2}) deposition on activated carbon (AC) is widely used for pollutant photodegradation. In this study, a simple and efficient method for preparing AC/TiO{sub 2} composites under microwave irradiation was developed for photocatalytic degradation of rhodamine B (RhB) under UV light. Results of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy revealed that TiO{sub 2} nanoparticles are anatase and rutile, with a spherical shape and a particle size of 20–50 nm and are well distributed on the AC surface. The UV–vis spectrum of TiO{sub 2} coated on AC showed an evident red-shift and exhibited stronger optical absorption capacity than pure TiO{sub 2}. The AC/TiO{sub 2} nanoparticles prepared at a microwave power of 700 W for 15 min exhibited 98% efficiency in removing RhB dye under UV irradiation for 30 min. The high photocatalytic activity of AC/TiO{sub 2}-700 W could be mainly attributed to the high sorption capacity of the mesoporous carbon material and high TiO{sub 2} content, which could produce higher quantity of ·OH. This study provides a rapid synthesis technique to prepare AC/TiO{sub 2} and a novel method to improve photocatalytic efficiency via synergistic effect for other catalytic systems.

  5. A new method of preparation of AgBr/TiO{sub 2} composites and investigation of their photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Xing Yangyang; Li Rui; Li Qiuye, E-mail: lqybys@yahoo.com.cn; Yang Jianjun [Henan University, Key Laboratory for Special Functional Materials (China)

    2012-12-15

    Silver bromide/titanium dioxide composites were first prepared using titanic acid nanobelts (TAN) as the TiO{sub 2} source. First, TAN reacted with AgNO{sub 3} to prepare Ag-incorporated TAN by the ion-exchange method, and then AgBr/TAN was obtained after adding NaBr. Finally, AgBr/TAN was transformed to AgBr/TiO{sub 2} composites by calcination. The post-treated calcination would not only convert TAN to TiO{sub 2} (H{sub 2}Ti{sub 2}O{sub 4}(OH){sub 2} {yields} 2H{sub 2}O + 2TiO{sub 2}), but also increase the effective contact between AgBr and TiO{sub 2}, further to improve the separation of photo-generated electron-holes. The advantage of this preparation method is the small particle size (ca. 10-20 nm) and well dispersion of AgBr on the surface of TiO{sub 2}, and close contact between AgBr and TiO{sub 2}. The effect of the different calcination temperature on the morphology, structure, and properties of AgBr/TiO{sub 2} composites was investigated in detail. The AgBr/TiO{sub 2} composites were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), and ultraviolet-visible diffuse reflectance spectra (UV-Vis DRS). Comparing with pure TAN, AgBr, and AgBr/P25 mixture, the AgBr/TiO{sub 2} composites exhibited enhanced photocatalytic activity in decomposition of methyl orange (MO) under visible light irradiation.

  6. Heusler compounds as ternary intermetallic nanoparticles: Co{sub 2}FeGa

    Energy Technology Data Exchange (ETDEWEB)

    Basit, Lubna; Wang Changhai; Jenkins, Catherine A; Balke, Benjamin; Ksenofontov, Vadim; Fecher, Gerhard H; Felser, Claudia [Johannes Gutenberg - Universitaet, Institut fuer analytische und anorganische Chemie, 55099 Mainz (Germany); Mugnaioli, Enrico; Kolb, Ute [Johannes Gutenberg - Universitaet, Institut fuer Physikalische Chemie, Elektronenmikroskopie-Zentrum Mainz (EMZM), 55099 Mainz (Germany); Nepijko, Sergej A; Schoenhense, Gerd [Johannes Gutenberg - Universitaet, Institut fuer Physik, 55099 Mainz (Germany); Klimenkov, Michael, E-mail: felser@uni-mainz.d [Institut fuer Materialforschung I, Forschungszentrum Karlsruhe GmbH, 76021 Karlsruhe (Germany)

    2009-04-21

    This work describes the preparation of ternary nanoparticles based on the Heusler compound Co{sub 2}FeGa. Nanoparticles with sizes of about 20 nm were synthesized by reducing a methanol impregnated mixture of CoCl{sub 2} {center_dot} 6H{sub 2}O, Fe(NO{sub 3}){sub 3} {center_dot} 9H{sub 2}O and Ga(NO{sub 3}){sub 3} {center_dot} xH{sub 2}O after loading on fumed silica. The dried samples were heated under pure H{sub 2} gas at 900 {sup 0}C. The obtained nanoparticles-embedded in silica-were investigated by means of x-ray diffraction (XRD), transmission electron microscopy, temperature dependent magnetometry and Moessbauer spectroscopy. All methods clearly revealed the Heusler-type L2{sub 1} structure of the nanoparticles. In particular, anomalous XRD data demonstrate the correct composition in addition to the occurrence of the L2{sub 1} structure. The magnetic moment of the particles is about 5{mu}{sub B} at low temperature in good agreement with the value of bulk material. This suggests that the half-metallic properties are conserved even in particles on the 10 nm scale.

  7. Room temperature ferromagnetism and phonon properties of pure and doped TiO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Apostolova, I.N. [University of Forestry, Faculty of Forest Industry, 10, Kl. Ohridsky Blvd., 1756 Sofia (Bulgaria); Apostolov, A.T. [University of Architecture, Civil Engineering and Geodesy, Faculty of Hydrotechnics, Department of Physics, 1, Hristo Smirnenski Blvd., 1046 Sofia (Bulgaria); Bahoosh, S.G. [Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Germany); Wesselinowa, J.M., E-mail: julia@phys.uni-sofia.bg [University of Sofia, Department of Physics, 5, J. Bouchier Blvd., 1164 Sofia (Bulgaria)

    2014-03-15

    We have considered the origin of RTFM in TiO{sub 2} nanoparticles (NPs). Further we have studied the properties of the E{sub g1} phonon mode. The phonon frequency of anatase TiO{sub 2} NPs increases whereas in the case of rutile TiO{sub 2} NPs it decreases as the particle size decreases. The phonon damping is always enhanced in the nanosized materials. The hardening of the E{sub g1} mode and the softening of the E{sub g3} mode in anatase TiO{sub 2} NPs could be explained with the different anharmonic spin–phonon interaction constants of these modes. The doping effects with different transition metal ions on the E{sub g1} phonon mode are also discussed. - Highlights: • The origin of RTFM in TiO{sub 2} nanoparticles is investigated. • With decreasing of particle size the phonon frequency of anatase and rutile TiO{sub 2} NPs increases and decreases, respectively. • This could be explained with the different anharmonic spin–phonon interaction constants of these modes. • The phonon damping is always enhanced in the nanosized materials. • The doping effects with different transition metal ions on the E{sub g1} phonon mode are also discussed.

  8. Preparation and performance evaluation of a Nafion-TiO{sub 2} composite membrane for PEMFCs

    Energy Technology Data Exchange (ETDEWEB)

    Jian-hua, Tian; Peng-fei, Gao; Zhi-yuan, Zhang; Wen-hui, Luo; Zhong-qiang, Shan [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2008-10-15

    Nafion/TiO{sub 2} composite membranes were studied for the application in proton exchange membrane fuel cell (PEMFC) to be used with the humidified or dry reactant gases of H{sub 2} and O{sub 2}. Composite membranes were prepared by carrying out in-situ sol-gel reaction of Ti (OC{sub 4}H{sub 9}){sub 4} in Nafion perfluorosulfonic acid films, such as Nafion112, 1135 and 115. The influence of the concentration of Ti (OC{sub 4}H{sub 9}){sub 4} isopropyl alcohol solution on the Ti content in the membranes of different thicknesses was investigated. The X-ray diffraction (XRD) analysis demonstrated that TiO{sub 2} in the composite membranes had a structure of anatase with an average particle size of 4.0 nm. The energy dispersive spectra (EDS) analysis indicated a symmetrical distribution of the TiO{sub 2} particles in the modified membranes. The water retention ability and electrochemical performance of Nafion/TiO{sub 2} composite membranes were evaluated using a single PEMFC operated with humidified or dry gas reactants during a long period. (author)

  9. The hidden order transition in URu{sub 2}Si{sub 2} investigated by high-resolution angle-resolved photoemission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Trinckauf, Jan; Haenke, Torben; Geck, Jochen [IFW Dresden (Germany); Shai, Daniel; Harter, John; Shen, Kyle [Cornell University, Ithaca (United States); Luke, Graeme [McMaster Univerity, Hamilton (Canada)

    2012-07-01

    We present a study of the hidden order transition in URu{sub 2}Si{sub 2} by means of high-resolution angle-resolved photoemission spectroscopy (ARPES). In particular, we find a strong excitation energy dependence of a flat quasi particle band that is associated with and strongly affected by the hidden order transition. We compare our ARPES data to density functional theory (DFT) calculations in the local density approximation (LDA)+U to simulate various degrees of 5f localization.

  10. Magnetic flux structures in RNi{sub 2}B{sub 2}C single crystals in normal and superconducting states

    Energy Technology Data Exchange (ETDEWEB)

    Vinnikov, L Ya; Veshchunov, I S [Institute of Solid State Physics, RAS, Chernogolovka, Moscow region 142432 (Russian Federation); Bud' ko, S L; Canfield, P C; Kogan, V G, E-mail: vinnik@issp.ac.r [Ames Laboratory U.S. DOE, Iowa State University, Ames, Iowa 50011 (United States)

    2009-03-01

    RNi{sub 2}B{sub 2}C single crystals, where R = Lu, Y, Er, Ho and Tb have been studied by high-resolution Bitter decoration technique, over the wide range temperatures and magnetic fields up to 2 T. Diverse vortex lattice structures were investigated: transition from triangular to square lattice for LuNi{sub 2}B{sub 2}C single crystals; peculiar vortex structures associated with antiferromagnetic (AFM) and weak-ferromagnetic (WFM) states below T{sub c} for ErNi{sub 2}B{sub 2}C single crystals . In addition, Bitter decoration revealed structures associated with a long range magnetic order in the non-superconducting TbNi{sub 2}B{sub 2}C as well as ErNi{sub 2}B{sub 2}C in the normal but magnetically ordered state.

  11. Carbon and TiO{sub 2} synergistic effect on methylene blue adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Simonetti, Evelyn Alves Nunes, E-mail: evelynalvesnunes@yahoo.com.br; Simone Cividanes, Luciana de; Campos, Tiago Moreira Bastos; Rossi Canuto de Menezes, Beatriz; Brito, Felipe Sales; Thim, Gilmar Patrocínio

    2016-07-01

    Due to its high efficiency, low cost and a simple operation, the adsorption process is an important and widely used technique for industrial wastewater treatment. Recent studies on the removal of artificial dyes by adsorption include a large number of adsorbents, such as: activated carbon, silicates, carbon nanotube, graphene, fibers, titanates and doped titanates. The carbon insertion in the TiO{sub 2} structure promotes a synergistic effect on the adsorbent composite, improving the adsorption and the charge-transfer efficiency rates. However, there are few studies regarding the adsorption capacity of TiO{sub 2}/Carbon composites with the carbon concentration. This study evaluates the effect of carbon (resorcinol/formaldehyde) insertion on TiO{sub 2} structure through the adsorption process. Adsorbents were prepared by varying the carbon weight percentages using the sol-gel method. The physicochemical properties of the catalysts prepared, such as crystallinity, particle size, surface morphology, specific surface area and pore volume were investigated. The kinetic study, adsorption isotherm, pH effect and thermodynamic study were examined in batch experiments using methylene blue as organic molecule. In addition, the effect of carbon phase on the adsorption capacity of TiO{sub 2}-carbon composite was deeply investigated. SEM micrographs showed that TiO{sub 2} phase grows along the carbon phase and FT-IR results showed the presence of Ti−O−C chemical bonding. The experiments indicate that the carbon phase acted as a nucleation agent for the growth of TiO{sub 2} during the sol-gel step, with a TiO{sub 2} structure suitable for blue methylene adsorption, resulting in a material with large surface area and slit-like or wedge-shaped pores. Further experiments will show the best carbon concentration for methylene blue adsorption using a TiO{sub 2} based material. - Highlights: • This article deals with the adsorption of methylene blue onto TiO{sub 2}-Carbon

  12. Catalytic behavior of Ni/Zr{sub x}Ti{sub 1-x}O{sub 2} and the effect of SiO{sub 2} doping in oxidative steam reforming of n-butane

    Energy Technology Data Exchange (ETDEWEB)

    Sago, Fumiaki [Department of Applied Chemistry, Faculty of Engineering, Oita University, 700 Dannoharu, Oita City, Oita 870-1192 (Japan); KYOCERA Corporation (Japan); Fukuda, Sho; Nagaoka, Katsutoshi; Nishiguchi, Hiroyasu; Takita, Yusaku [Department of Applied Chemistry, Faculty of Engineering, Oita University, 700 Dannoharu, Oita City, Oita 870-1192 (Japan); Sato, Katsutoshi [Department of Applied Chemistry, Faculty of Engineering, Oita University, 700 Dannoharu, Oita City, Oita 870-1192 (Japan); Research Fellow of the Japan Society for the Promotion of Science, Washington, DC (United States)

    2009-10-15

    Catalytic behaviors of TiO{sub 2}-, Zr{sub 0.5}Ti{sub 0.5}O{sub 2}-, and ZrO{sub 2}-supported Ni catalysts were investigated for oxidative steam reforming of n-C{sub 4}H{sub 10} at 723 K. The composite oxide support, Zr{sub 0.5}Ti{sub 0.5}O{sub 2}, shows high specific surface area (136 m{sup 2}/g), leading to fine Ni particles. Thus, the Ni/Zr{sub 0.5}Ti{sub 0.5}O{sub 2} catalyst exhibits higher and more stable activity than that exhibited by other catalysts. However, relatively large amounts of coke are deposited on the catalyst during reaction. Thus, to retard carbon deposition, the influence of SiO{sub 2} additive was studied. Large amounts of SiO{sub 2} additive (5 or 10 mol%) decrease initial activity; at 10 mol%, degradation is also induced by oxidation of Ni{sup 0}. However, small amounts of SiO{sub 2} additive (1.5 mol%) effectively retard coking without lowering initial activity. The resultant Ni/Zr{sub 0.5}Ti{sub 0.5}O{sub 2}-SiO{sub 2} (1.5 mol%) catalyst exhibits high and stable activity without coking. (author)

  13. Synthesis, characterization and thermal analysis of polyaniline/ZrO{sub 2} composites

    Energy Technology Data Exchange (ETDEWEB)

    Wang Shaoxu [Thermochemisty Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023 (China); College of Environmental Scinece and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Tan Zhicheng [Thermochemisty Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023 (China) and College of Environmental Scinece and Engineering, Dalian Jiaotong University, Dalian 116028 (China)]. E-mail: tzc@dicp.ac.cn; Li Yansheng [College of Environmental Scinece and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Sun Lixian [Thermochemisty Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023 (China); Zhang Tao [Thermochemisty Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023 (China)

    2006-02-15

    Conducting polyaniline-zirconium dioxide (PANI/ZrO{sub 2}) composites were synthesized by 'in situ' deposition technique in the presence of hydrochloric acid (HCl) as dopant by adding the fine grade powder (average particle size of approximately 20 nm) of ZrO{sub 2} into the polymerization reaction mixture of aniline. The composites obtained were characterized by infrared spectra (IR) and X-ray diffraction (XRD) and thermogravimetric analysis (TGA). TG curves and DTG curves of the composites suggest that the thermal degradation process of PANI/ZrO{sub 2} composites proceeds in two-steps and the composites are more thermally stable than that of the pure PANI. The improvement in the thermal stability for the composites is attributed to the interaction between PANI and ZrO{sub 2}, which restricts the thermal motion of PANI chains and shields the degradation of PANI in the composites.

  14. Synthesis, characterisation and stability of Cu{sub 2}O nanoparticles produced via reverse micelles microemulsion

    Energy Technology Data Exchange (ETDEWEB)

    Dodoo-Arhin, D. [University of Trento, Department of Materials Engineering and Industrial Technologies, via Mesiano 77, 38100 Trento (Italy); Leoni, M., E-mail: Matteo.Leoni@unitn.it [University of Trento, Department of Materials Engineering and Industrial Technologies, via Mesiano 77, 38100 Trento (Italy); Scardi, P. [University of Trento, Department of Materials Engineering and Industrial Technologies, via Mesiano 77, 38100 Trento (Italy); Garnier, E. [Laboratoire de Catalyse en Chimie Organique, UMR CNRS 6503, Universite de Poitiers, 40 Av. du Recteur Pineau, 86022 Poitiers (France); Mittiga, A. [ENEA C.R. Casaccia, via Anguillarese 301, 00123 Roma (Italy)

    2010-08-01

    Cuprite (Cu{sub 2}O) nanoparticles were synthesized at room temperature via reduction of CuCl{sub 2}.2H{sub 2}O by NaBH{sub 4} in water/n-heptane microemulsion stabilised by the non-ionic Brij30 surfactant. Whole Powder Pattern Modelling of the X-ray diffraction patterns shows the presence of a bimodal size distribution in the nanopowders, with a fraction of domains in the 10-40 nm range and a smaller one below 10 nm. Linear and planar defects are absent. A relationship between the average size of the larger particles and the quantity of water in the system was obtained. The stability of cuprite under visible light irradiation both during the synthesis and after the preparation was investigated, showing that a self-catalytic conversion of Cu{sub 2}O into CuO takes place in water.

  15. Effects of O{sub 2} and SO{sub 2} on the Capture Capacity of a Primary-Amine Based Polymeric CO{sub 2} Sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Hallenbeck, Alexander P; Kitchin, John R

    2013-08-01

    Post combustion CO{sub 2} capture is most commonly carried out using an amine solution that results in a high parasitic energy cost in the stripper unit due to the need to heat the water which comprises a majority of the amine solution. It is also well known that amine solvents suffer from stability issues due to amine leaching and poisoning by flue gas impurities. Solid sorbents provide an alternative to solvent systems that would potentially reduce the energy penalty of carbon capture. However, the cost of using a particular sorbent is greatly affected by the usable lifetime of the sorbent. This work investigated the stability of a primary amine-functionalized ion exchange resin in the presence of O{sub 2} and SO{sub 2}, both of which are constituents of flue gas that have been shown to cause degradation of various amines in solvent processes. The CO{sub 2} capture capacity was measured over multiple capture cycles under continuous exposure to two simulated flue gas streams, one containing 12 vol% CO{sub 2}, 4% O{sub 2}, 84% N{sub 2}, and the other containing 12.5 vol% CO{sub 2}, 4% O{sub 2}, 431 ppm SO{sub 2}, balance N{sub 2} using a custom-built packed bed reactor. The resin maintained its CO{sub 2} capture capacity of 1.31 mol/kg over 17 capture cycles in the presence of O{sub 2} without SO{sub 2}. However, the CO{sub 2} capture capacity of the resin decreased rapidly under exposure to SO{sub 2} by an amount of 1.3 mol/kg over 9 capture cycles. Elemental analysis revealed the resin adsorbed 1.0 mol/kg of SO{sub 2}. Thermal regeneration was determined to not be possible. The poisoned resin was, however, partially regenerated with exposure to 1.5M NaOH for 3 days resulting in a 43% removal of sulfur, determined through elemental analysis, and a 35% recovery of CO{sub 2} capture capacity. Evidence was also found for amine loss upon prolonged (7 days) continuous exposure to high temperatures (120 C) in air. It is concluded that desulfurization of the flue gas

  16. Surface passivation and conversion of SnO{sub 2} to SnS{sub 2} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Zervos, M., E-mail: zervos@ucy.ac.cy [Nanostructured Materials and Devices Laboratory and Department of Mechanical and Manufacturing Engineering, University of Cyprus, P.O. Box 20537, Nicosia 1678 (Cyprus); Mihailescu, C.N. [Nanotechnology Research Center and Department of Mechanical and Manufacturing Engineering, University of Cyprus, P.O. Box 20537, Nicosia 1678 (Cyprus); National Institute for Laser, Plasma and Radiation Physics, Str. Atomistilor, P.O. Box MG-36, 077125 Magurele (Romania); Giapintzakis, J. [Nanotechnology Research Center and Department of Mechanical and Manufacturing Engineering, University of Cyprus, P.O. Box 20537, Nicosia 1678 (Cyprus); Othonos, A. [Center of Ultrafast Science, Nanotechnology Research Center and Department of Physics, University of Cyprus, P.O. Box 20537, Nicosia 1678 (Cyprus); Luculescu, C.R. [National Institute for Laser, Plasma and Radiation Physics, Str. Atomistilor, P.O. Box MG-36, 077125 Magurele (Romania)

    2015-08-15

    Highlights: • SnO{sub 2} nanowires contain SnS{sub 2} after exposure to H{sub 2}S up to 300 °C. • The resistance of SnO{sub 2} nanowires is reduced significantly after exposure to H{sub 2}S at 300 °C. • SnO{sub 2} nanowires are fully converted to SnS{sub 2} at 400 °C under H{sub 2}S. • The photoluminescence of SnO{sub 2}/SnS{sub 2} nanowires does not change upon exposure to H{sub 2}S. • SnO{sub 2} nanowires are converted into SnS{sub 2} crystals upon exposure to H{sub 2}S above 400 °C. - Abstract: SnO{sub 2} nanowires have been grown on Si(0 0 1) via the vapour–liquid–solid mechanism at 800 °C and then exposed to H{sub 2}S between 300 and 600 °C. The SnS{sub 2}/SnO{sub 2} nanowires obtained at 300 °C consist of tetragonal rutile SnO{sub 2} and hexagonal SnS{sub 2}, exhibited defect related photoluminescence at 2.4 eV and have smaller resistances than the SnO{sub 2} nanowires. We show how the Fermi level pinning at the surface of a SnS{sub 2}/SnO{sub 2} nanowire would lead to an increase of the one dimensional electron gas density, smaller barrier height and resistance. The SnO{sub 2} nanowires are fully converted into hexagonal SnS{sub 2} at 400 °C resulting into photoluminescence at 2.4 and 2.8 eV but have considerably larger resistances than the SnO{sub 2} nanowires which are eliminated and converted into SnS{sub 2} crystals above 400 °C.

  17. Enrichment of Sc{sub 2}O{sub 3} and TiO{sub 2} from bauxite ore residues

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Bona; Li, Guanghui, E-mail: liguangh@csu.edu.cn; Luo, Jun; Ye, Qing; Liu, Mingxia; Peng, Zhiwei; Jiang, Tao

    2017-06-05

    Highlights: • Sc{sub 2}O{sub 3} and TiO{sub 2} from bauxite ore residue were successfully enriched. • H{sub 3}PO{sub 4} and NaOH were efficient for enriching Sc{sub 2}O{sub 3} and TiO{sub 2} by removing SiO{sub 2}, Al{sub 2}O{sub 3}, and partial Fe{sub 2}O{sub 3} and CaO. • Enriching mechanism of Sc{sub 2}O{sub 3} and TiO{sub 2} was explicitly explained. - Abstract: As a major byproduct generated in the alumina industry, bauxite ore residue is an important reserve of scandium and titanium. In this study, the feasibility and mechanism of enriching Sc{sub 2}O{sub 3} and TiO{sub 2} from a non-magnetic material, which was obtained from carbothermal reductive roasting and magnetic separation of bauxite ore residue, were investigated based on a two-step (acidic and alkali) leaching process. It was revealed that approximately 78% SiO{sub 2} and 30–40% of CaO, FeO and Al{sub 2}O{sub 3} were removed from a non-magnetic material with 0.0134 wt.% Sc{sub 2}O{sub 3} and 7.64 wt.% TiO{sub 2} by phosphoric acidic leaching, while about 95% Al{sub 2}O{sub 3} and P{sub 2}O{sub 5} were further leached by subsequent sodium hydroxide leaching of the upper-stream leach residue. A Sc{sub 2}O{sub 3}-, TiO{sub 2}- rich material containing 0.044 wt.% Sc{sub 2}O{sub 3} and 25.5 wt.% TiO{sub 2} was obtained, the recovery and the enrichment factor of Sc{sub 2}O{sub 3} and TiO{sub 2} were about 85% and 5, respectively. The enrichment of Sc{sub 2}O{sub 3} was attributed to higher pH (>3.3) of phosphoric acid solution than its dissolution pH{sup 0}, and the enrichment of TiO{sub 2} was mainly associated with the insoluble perovskite (CaTiO{sub 3}) in the acidic solution at ambient temperature. As Sc{sub 2}O{sub 3} and TiO{sub 2} cannot be dissolved in the alkali solution, they were further enriched in the leach residue.

  18. Scintillation response of BaF sub 2 and YAlO sub 3 Ce) to energetic ions

    CERN Document Server

    Slunga, E; Ideguchi, E; Kérek, A; Klamra, W; Marel, J V D; Novák, D; Norlin, L O

    2001-01-01

    The scintillation response of BaF sub 2 and YAP:Ce to protons, alpha particles, sup 1 sup 6 O and sup 2 sup 8 Si ions in the 5-30 MeV range has been investigated. The ratio between the fast and slow parts of the scintillator signal for BaF sub 2 has been used to separate protons, alpha particles and heavier ions, and the dependence of this ratio on the particle energy has been studied. The time constants and intensities of the two components of the YAP:Ce signal were measured, as were the time constant and intensity of the weak component of the slow part of the BaF sub 2 signal. Furthermore, the dependence of the light yield on the particle energy has been investigated for both BaF sub 2 and YAP:Ce.

  19. Synthesis of UO{sub 2} and ThO{sub 2} doped with Gd{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Baena, Angela [KU Leuven, Department of Chemistry, Celestijnenlaan 200F, P.O. Box 2404, B-3001 Heverlee (Belgium); Belgian Nuclear Research Centre (SCK-CEN), Institute for Nuclear Materials Science, Boeretang 200, B-2400 Mol (Belgium); Cardinaels, Thomas, E-mail: thomas.cardinaels@sckcen.be [Belgian Nuclear Research Centre (SCK-CEN), Institute for Nuclear Materials Science, Boeretang 200, B-2400 Mol (Belgium); Vos, Benedict [Belgian Nuclear Research Centre (SCK-CEN), Institute for Nuclear Materials Science, Boeretang 200, B-2400 Mol (Belgium); Binnemans, Koen [KU Leuven, Department of Chemistry, Celestijnenlaan 200F, P.O. Box 2404, B-3001 Heverlee (Belgium); Verwerft, Marc [Belgian Nuclear Research Centre (SCK-CEN), Institute for Nuclear Materials Science, Boeretang 200, B-2400 Mol (Belgium)

    2015-06-15

    Uranium dioxide (urania, UO{sub 2}) and thorium dioxide (thoria, ThO{sub 2}) doped with gadolinium oxide (gadolinia, Gd{sub 2}O{sub 3}) were prepared via solid-state synthesis. For Gd{sub 2}O{sub 3}-doped ThO{sub 2}, also an alternative, semi-dry process (“suspension coating”) was applied in which Gd{sub 2}O{sub 3}-coated ThO{sub 2} powder was produced via suspension drying followed by calcination. The microstructure and homogeneity of the materials were investigated by ceramography, EPMA and XRD. Solid-state synthesis is a convenient method to produce Gd{sub 2}O{sub 3}-doped UO{sub 2}. However, this route was found to be inappropriate to obtain Gd{sub 2}O{sub 3}-doped ThO{sub 2} with an acceptable microstructure and homogeneity. The suspension coating process reported in this work is a simple and practical method to overcome these issues.

  20. Ion-molecule interactions in crossed-beams. [N/sup +/-H/sub 2/; F/sup +/-H; CO/sub 2//sup +/-D/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, S.G.

    1980-09-01

    Interactions of the ions N/sup +/, F/sup +/, and CO/sub 2//sup +/ with H/sub 2/ and/or its isotopes were examined using the crossed-beam technique in the low (< 4 eV) initial relative energy. For the reaction N/sup +/(/sup 3/P) + H/sub 2/ ..-->.. NH/sup +/ + H, complex formation dominates up to 1.9 eV and a substantial interaction occurs between all collision partners up to 3.6 eV. The distribution of N/sup +/ scattered nonreactively from H/sub 2/ also showed a long-lived complex channel below 1.9 eV. The reaction F/sup +/(/sup 3/P) + H/sub 2/ ..-->..FH/sup +/ + H proceeded by a direct reaction mechanism at 0.20 to 1.07 eV. The reaction CO/sub 2//sup +/ + D/sub 2/ ..-->.. DCO/sub 2//sup +/ + D gives asymmetric product distributions at 0.27 eV and above, indicating a direct reaction mechanism. Results indicated that there are probably barriers in the exit channels for DCO/sub 2//sup +/, DCO/sup +/, and D/sub 2/O/sup +/ products. The electronic state distributions of the N/sup +/, F/sup +/, and CO/sub 2//sup +/ beams was investigated using beam attenuation and total luminescence techniques.

  1. CO{sub 2} geothermal heat probe - Phase 2; CO{sub 2}-Erdwaermesonde - Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Grueniger, A.; Wellig, B.

    2009-12-15

    In this project the fluid dynamics and thermodynamics inside a CO{sub 2} geothermal heat probe have been investigated. The functionality of such a probe, which works like a thermosyphon, was analyzed by means of a simulation model in MATLAB. The model couples the behaviour inside the heat probe with the heat conduction in the earth. A parameter study revealed that the self-circulation character of such a probe leads to flattening of the vertical earth temperature profile near the probe and, hence, leads to more uniform heat removal along the probe. The circulation of CO{sub 2} even goes on when the heat pump is off. This might be advantageous for the regeneration phase. The heat transfer resistance of the evaporating CO{sub 2} film flowing down the probe wall is very small compared to the conduction resistance of the earth. Therefore, no difference has been found between the performances of a conventional heat pipe and a configuration where the liquid phase injection is distributed on different height stages along the probe. It is estimated that the seasonal performance factor of heat pumps can be improved by 15-25% with a CO{sub 2} geothermal heat probe. The main advantage is that the heat transfer to the evaporator of the heat pump (condensation of CO{sub 2} / evaporation of refrigerant) is much more efficient than in a conventional brine probe without phase change. Furthermore, no circulation pump is needed. (authors)

  2. Crystal structure change of Li{sub 2+x}TiO{sub 3+y} tritium breeder under moist air

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Masanori, E-mail: masahara@ctg.u-toyama.ac.j [Hydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555 (Japan); Togashi, Yuka; Matsuyama, Masao [Hydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555 (Japan); Oya, Yasuhisa; Okuno, Kenji [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Ohya 836, Suruga-ku Shizuoka 422-8529 (Japan)

    2010-09-30

    To investigate the aging behavior of Li{sub 2+x}TiO{sub 3+y}, the materials Li{sub 2.0}TiO{sub 3+y}, Li{sub 2.2}TiO{sub 3+y} and Li{sub 2.4}TiO{sub 3+y} were stored under moist air at ambient temperature. Under these conditions the weight of Li{sub 2.0}TiO{sub 3+y} increased by only 1% in 100 days, which provides evidence for the high chemical stability of Li{sub 2}TiO{sub 3}. In comparison, under the same storage conditions the weights of Li{sub 2.2}TiO{sub 3+y} and Li{sub 2.4}TiO{sub 3+y} increased by 14% and 18%, respectively. The observed weight gain is attributed to the uptake of water, and to the reaction of a by-product of Li{sub 2+x}TiO{sub 3+y} with water and carbon dioxide. The weight gain curves were evaluated by the Jander equation. From the analysis, it was possible to obtain the diffusion coefficient of water through Li{sub 2}TiO{sub 3} particles at ambient temperature. The determined value was 2 x 10{sup -17} m{sup 2}/s.

  3. Oxygen sensitivity of algal H{sub 2}-production

    Energy Technology Data Exchange (ETDEWEB)

    Ghirardi, M.L.; Seibert, M. [National Renewable Energy Lab., Golden, CO (United States); Togasaki, R.K. [Indiana Univ., Bloomington, IN (United States)

    1997-12-31

    Photoproduction of H{sub 2} by green algae utilizes electrons originating from the photosynthetic oxidation of water and does not require metabolic intermediates. However, algal hydrogenases are extremely sensitive to O{sub 2}, which limits their usefulness in future commercial H{sub 2}-production systems. We designed an experimental technique for the selection of O{sub 2}tolerant, H{sub 2}-producing variants of Chlamydomonas reinhardtii based on the ability of wild-type cells to survive a short (20 min) exposure to metronidazole in the presence of controlled concentrations of O{sub 2}. The number of survivors depends on the metronidazole concentration, light intensity, preinduction of the hydrogenase, and the presence or absence of O{sub 2}. Finally, we demonstrate that some of the selected survivors in fact exhibit H{sub 2}-production capacity that is less sensitive to O{sub 2} than the original wild-type population. 17 refs., 1 tab.

  4. Synthesis, crystal structure, and properties of Na{sub 2}RbAuO{sub 2}; Synthese, Kristallstruktur und Eigenschaften von Na{sub 2}RbAuO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mudring, A.V.; Jansen, M. [Max-Planck-Inst. fuer Festkoerperforschung, Stuttgart (Germany)

    2001-02-01

    Single phase samples of Na{sub 2}RbAuO{sub 2} were prepared by reacting RbAu with Na{sub 2}O{sub 2} in an equimolar ratio in sealed silver cylinders (placed under argon in glas tubes) at 400 C for two weeks. The colourless single crystals of needle shaped habitus decompose immediately when exposed to air. Na{sub 2}RbAuO{sub 2} (Pearsoncode oP12, Pnnm, a = 992.76(6), b = 559.03(3), c = 408.64(3) pm, Z = 2, 414 reflections with I{sub o} > 2{sigma}(I), R{sub 1} = 0.0363, wR{sub 2} = 0.1057) crystallizes isotypic with Na{sub 2}KAuO{sub 2}. Besides linear [O-Au-O] units, which are characteristic for oxoaurate(I), the structure reveals uncommon low coordination numbers for the alkali metal cations. (orig.)

  5. Effect of PdO on TiO(sub2) Loading on Chemochromic Detection of Hydrogen

    Science.gov (United States)

    Mohajeri, Nahid; T-Rassisi, Ali; Bokerman, Gary; Captain, Janine E.; Peterson, Barbara V.; Whitten, Mary; Berger, Cristina

    2007-01-01

    Safety is always a concern in all applications that utilize hydrogen (H(sub2)) in one form or the other. Hydrogen leaks are invisible and odorless. In addition, blending odorants or additives into hydrogen in a manner similar to natural gas is generally undesirable for certain applications including proton exchange membrane fuel cells. To facilitate detection of the location of hydrogen leaks, a special chemochromic H(sub2) sensing material that employs titania (Ti0(sub2)) supported palladium oxide (PdO) pigments encapsulated within a special silicone matrix has been developed at the Florida Solar Energy Center (FSEC). Several batches of PdO H(sub2) sensing pigments were synthesized using various Ti0(sub2) supports and their hydrogen detection activity determined. TEM and Particle size distribution analysis showed that smaller particles with hemispherical crystalline structure produced faster coloration kinetics when exposed to H(sub2) gas. However, uniformly distributed PdO particles on the Ti0(sub2) surface displayed greater color contrast, quantified by delta epsilon measurements. XRD analysis indicated that the crystalline phase of Ti0(sub2) had no effect on the chemochromic performance of the pigments in laboratory environment.

  6. The contribution of valence unstable ytterbium states into kinetic properties of YbNi{sub 2-x}Ge{sub 2+x} and YbCu{sub 2-x}Si{sub 2+x}

    Energy Technology Data Exchange (ETDEWEB)

    Kuzhel, B.C. [Department of Physics, Ivan Franko National University of Lviv, 50 Dragomanow Str., 79005, Lviv (Ukraine)]. E-mail: kuzhelb@org.lviv.net; Shcherba, I.D. [Department of Physics, Ivan Franko National University of Lviv, 50 Dragomanow Str., 79005, Lviv (Ukraine); Institute of Techniques, Academy of Pedagogy, Podchorozych 2, 30-084, Krakow (Poland); Kravchenko, I.I. [Department of Physics, University of Florida, P.O. Box 118440, Gainesville, FL 32611 (United States)]. E-mail: kravch@phys.ufl.edu

    2006-11-30

    The intermetalic YbNi{sub 2-x}Ge{sub 2+x} (-0.25>=x>=0.25) and YbCu{sub 2-x}Si{sub 2+x} (-0.20>=x>=0.20) alloy systems (CeGa{sub 2}Al{sub 2} -type crystal structure) were studied by measuring X-ray absorption and diffraction at room temperatures as well as electrical resistivity and thermopower in the 4.2-300K temperature range. The temperature dependence of the contribution of valence unstable Yb ions to the total electrical resistance has been analyzed. The qualitative estimation of this contribution has been performed by utilizing the following equation:{delta}{rho}{sub Yb}(T)={rho}{sub exp}(T)-{rho}{sub YbCu{sub 2}Ge{sub 2}}(T)-{delta}{rho}{sub 4.2K},where {delta}{rho}{sub YbCu{sub 2}Ge{sub 2}}(T) is the temperature dependence of YbCu{sub 2}Ge{sub 2} electrical resistance, {delta}{rho}{sub 4.2}={rho}{sub 4.2}(exp)-{rho}{sub 4.2}(YbCu{sub 2}Ge{sub 2})

  7. Crystallization behavior of (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Moo-Chin [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Cheng, Chih-Wei; Chang, Kuo-Ming [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.t [Department of Materials Science and Engineering, National United University, 1 Lien-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)

    2010-07-02

    The crystallization behavior of the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and energy dispersive spectroscopy (EDS). The crystalline phase was composed of {beta}-spodumene. The isothermal crystallization kinetics of {beta}-spodumene from the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses has also been studied by a quantitative X-ray diffraction method. The activation energy of {beta}-spodumene formation decreases from 359.2 to 317.8 kJ/mol when the Na{sub 2}O content increases from 0 to 0.4 mol and it increases from 317.8 to 376.9 kJ/mol when the Na{sub 2}O content increases from 0.4 to 0.6 mol. The surface nucleation and plate-like growth were dominant in the crystallization of the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses.

  8. Microstructures of laser-treated Al{sub 2}O{sub 3}-ZrO{sub 2}-CeO{sub 2} composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zanhwey [Institute of Materials Science and Engineering, National Sun Yat-Sen University, Kaohsiung (Taiwan, Province of China); Ho Newjin [Institute of Materials Science and Engineering, National Sun Yat-Sen University, Kaohsiung (Taiwan, Province of China); Shen Pouyan [Institute of Materials Science and Engineering, National Sun Yat-Sen University, Kaohsiung (Taiwan, Province of China)

    1995-06-15

    This work uses room temperature X-ray diffraction and electron microscopy to investigate the effect of CO{sub 2} laser treatments (800-2000W, 10-15s) on phase transformations and microstructural modification of sintered (1600 C, 4h) disks A{sub x}Z{sub y}C{sub z}(where A, Z and C denote Al{sub 2}O{sub 3}, ZrO{sub 2} and CeO{sub 2} respectively, and the subscripts represent molar ratios). Laser treatments under these conditions caused melting and more or less sublimation of all the samples; subsequent solidification and condension (predominant for CeO{sub 2}-rich composition) resulted in different microstructures between the samples. Dendritic and cellular domain structures due both to eutectic growth of {alpha}-Al{sub 2}O{sub 3} and ZrO{sub 2}-CeO{sub 2} solid solution were found in specimens A{sub 30}Z{sub 63}C{sub 7} and A{sub 70}Z{sub 27}C{sub 3} respectively. In the CeO{sub 2}-rich specimen A{sub 40}Z{sub 12}C{sub 48} a drastic effect of condensation caused dendritic clusters of CeO{sub 2} cubes (fluorite structure with minor amount of ZrO{sub 2} and Al{sub 2}O{sub 3} in solid solution) which overlaid on an Al{sub 2}O{sub 3}-rich matrix, predominantly CeAlO{sub 3}. Condensation through a rapidly solidifying liquid caused incorporation of Al{sub 2}O{sub 3} in the fluorite structure and hence deviation from the octahedral shape predicted by the periodic bond chain model. Solute (Al{sub 2}O{sub 3}) trapping also suppressed the martensitic transformation of tetragonal (t-) to monoclinic (m-) ZrO{sub 2} as manifested by the dendritic t-ZrO{sub 2} cooled from the Al{sub 2}O{sub 3}-ZrO{sub 2} eutectic. Laser treatment increased the Ce{sup 2+}/Ce{sup 4+} ratio and hence darkened the samples. (orig.)

  9. Behaviour of high purity UO{sub 2}/H{sub 2}O interfaces under helium beam irradiation in deaerated conditions; Comportement des interfaces UO{sub 2}/H{sub 2}O de haute purete sous faisceau d'ions He{sup 2+} en milieu desaere

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, E

    2005-11-15

    A question put within the framework of the nuclear fuel storage worn in geological site is what become to them in the presence of water. The aim of a fundamental program, of PRECCI project (ECA), is to highlight the behaviour of interfaces which can be used as models for the interfaces nuclear spent fuel/water if the fuel is uranium UO{sub 2} dioxide. This doctorate is interested in the effect of the alpha activity which is the only one that exist in the spent fuel after long periods. The aim is to identify the mechanisms of alteration and of leaching of surfaces under alpha irradiation. A method is developed to irradiate UO{sub 2}/H{sub 2}O interfaces in deaerated conditions with the beam of He{sup 2+} produced by a cyclotron. The He{sup 2+} ions cross an UO{sub 2} disc and emerge in water with an energy of 5 MeV. Leachings under irradiation are carried with a large range of particles flux. The post-irradiation characterization of the surface of the discs realised by micro-Raman spectroscopy allowed to identify the alteration layer. It is made up of studtite UO{sub 2}(O{sub 2}),4H{sub 2}O, and of schoepite UO{sub 3},xH{sub 2}O. The analysis of the solutions shows that the uranium release strongly increases. The electrochemical properties of the interfaces under irradiation strongly differ from those before irradiation. This work allows to propose that the radiolytic species seen by the interface are it during the heterogeneous phase of evolution of the traces and are species of short lives. Modeling show that the radiolytic radicals species can migrate toward the interface and react with the UO{sub 2} surface. (author)

  10. High efficiency nanocomposite sorbents for CO{sub 2} capture based on amine-functionalized mesoporous capsules

    Energy Technology Data Exchange (ETDEWEB)

    Qi, G.G.; Wang, Y.B.; Estevez, L.; Duan, X.N.; Anako, N.; Park, A.H.A.; Li, W.; Jones, C.W.; Giannelis, E.P. [Cornell University, Ithaca, NY (United States). Dept. of Material Science & Engineering

    2011-02-15

    A novel high efficiency nanocomposite sorbent for CO{sub 2} capture has been developed based on oligomeric amine (polyethylenimine, PEI, and tetraethylenepentamine, TEPA) functionalized mesoporous silica capsules. The newly synthesized sorbents exhibit extraordinary capture capacity up to 7.9 mmol g{sup -1} under simulated flue gas conditions (pre-humidified 10% CO{sub 2}). The CO{sub 2} capture kinetics were found to be fast and reached 90% of the total capacities within the first few minutes. The effects of the mesoporous capsule features such as particle size and shell thickness on CO{sub 2} capture capacity were investigated. Larger particle size, higher interior void volume and thinner mesoporous shell thickness all improved the CO{sub 2} capacity of the sorbents. PEI impregnated sorbents showed good reversibility and stability during cyclic adsorption-regeneration tests (50 cycles).

  11. Electrochemical study of a novel high performance supercapacitor based on MnO{sub 2}/nitrogen-doped graphene nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Naderi, Hamid Reza, E-mail: hrnaderi@ut.ac.ir [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Norouzi, Parviz, E-mail: norouzi@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); 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)

    2016-03-15

    Graphical abstract: - Highlights: • MnO{sub 2} nanoparticles was prepared by sonochemical method. • MnO{sub 2} are anchored on the surface of nitrogen-doped reduced graphene oxide (NRGO). • MnO{sub 2}/NRGO nanocomposite show high capacitance, good rate and cycling performance. • The nanocomposite electrode exhibits specific capacitance of 522 F g{sup −1} in 2 mV s{sup −1}. • The electrode reveals 97% retention of initial capacitance after 4000 cycles. - Abstract: A new nanocomposite was synthesized via deposition of MnO{sub 2} on Nitrogen-doped reduced graphene (MnO{sub 2}/NRGO) by sonochemical method, in which, the particles of manganese oxide were uniformly distributed on NRGO sheets. The structure and morphology of MnO{sub 2}/NRGO nanocomposites are characterized by X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical supercapacitive performance of the nanocomposite was investigated by cyclic voltammetry (CV), continuous cyclic voltammetry (CCV), galvanostatic charge/discharge, and electrochemical impedance spectroscopy (EIS) methods. The MnO{sub 2}/NRGO nanocomposite shows enhanced specific capacitance of 522 F g{sup −1} at 2 mV s{sup −1} and its high synergistic effect was compared with MnO{sub 2}/RGO. The high specific capacitance and exceptionally high cyclic stability of MnO{sub 2}/NRGO attributes to the doping of nitrogen and uniform dispersion of MnO{sub 2} particles on NRGO. The CCV showed that the capacity retention for MnO{sub 2}/NRGO and MnO{sub 2}/RGO still maintained at 96.3% and 93% after 4000 CVs. The improved supercapacitive performance enables this nanocomposite as efficient electrode material for supercapacitor electrodes.

  12. Obtention of TiO{sub 2} thin films by laser ablation; Obtencion de peliculas delgadas de TiO{sub 2} por ablacion laser

    Energy Technology Data Exchange (ETDEWEB)

    Escobar A, L. [Departmaneto de Fisica, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, C.P. 11801, Mexico, D.F. (Mexico); Haro P, E.; Camacho L, M.A.; Fernandez G, M.; Jimenez J, J.; Sanchez P, A. [Departamento de Fisica, Universidad Autonoma Metropolitana Iztapalapa, Apdo. Postal 55-532, C.P. 09340 Mexico D.F. (Mexico)

    1998-12-31

    The thin films of TiO{sub 2} have been investigated extensively in the last years, since they have a broad variety of applications, which owing to their less usual chemical, electrical and optical properties. In this work are presented the obtained results to deposit TiO{sub 2} thin films over glass substrates utilizing the Laser ablation technique. It has been deposited thin films at different substrate temperatures and different oxygen pressures, with the purpose to study the influence of these deposit parameters in the structural characteristics of the obtained films. The structural characterization was realized through Raman spectroscopy and X-ray diffraction (XRD), the superficial morphology was verified by Scanning Electron Microscopy (SEM). The results show that the obtained films were TiO{sub 2} in rutile phase, getting this with the substrates at low temperature, its morphology shows a soft surface with some sprinkling particles and a good adherence. (Author)

  13. Pre-eutectic densification in MgF/sub 2/-CaF/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Hu, S C; De Jonghe, L C

    1982-04-01

    Increased densification rates were found as much as 200/sup 0/C below the eutectic temperature (980/sup 0/C) for MgF/sub 2/ containing small amounts of CaF/sub 2/. Constant heating rate and constant temperature sintering data, as well as microstructural developments indicated that solid state grain-boundary transport rates had been enhanced by the eutectic forming additive. The effect saturated at about 1 wt % CaF/sub 2/. The results suggest that densification of ceramic powders could be favorably affected without a substantial increase in the grain growth rate, by the addition of small amounts of eutectic forming additives, and sintering below the eutectic temperature. 6 figures.

  14. Superconducting tunnel junctions on MgB{sub 2} using MgO and CaF{sub 2} as a barrier

    Energy Technology Data Exchange (ETDEWEB)

    Sakoda, Masahito, E-mail: sakoda@cc.tuat.ac.jp [Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16, Koganei, Tokyo 184-8588 (Japan); Aibara, Masato; Mede, Kazuya; Kikuchi, Motoyuki; Naito, Michio [Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16, Koganei, Tokyo 184-8588 (Japan)

    2016-11-15

    Highlights: • We have revised the manuscript according to reviewer's comments. The details are in “Response to Reviewers”. • Superconducting junctions with MgO and CaF{sub 2} barrier were fabricated in order to improve the quality of junctions. • In SIN junctions with MgO barrier, clear superconducting gap was observed. (). • In SIS junctions with CaF2 barrier, Josephson current was observed over 30 K. (). • The compatibility of each barrier material at the upper and lower interfaces was clarified. (). - Abstract: We report the fabrication of superconducting tunnel junctions, both of superconductor–insulator-normal metal (SIN) and superconductor–insulator-superconductor (SIS), on MgB{sub 2} using MgO and CaF{sub 2} as a barrier. The SIN junctions fabricated using an MgO barrier showed excellent quasi-particle characteristics, including a large superconducting gap (Δ) of 2.5–3 meV and a low zero-bias conductance. We have also fabricated SIS junctions with an MgO barrier, but the quasi-particle characteristics of the SIS junctions are not as good as those of the SIN junctions, namely a reduced superconducting gap and a high zero-bias conductance. It appears that top MgB{sub 2} electrodes do not grow well on an MgO barrier, which is also suggested from in-situ RHEED observation. The SIN junctions fabricated using a CaF{sub 2} barrier showed less sharp quasi-particle characteristics than using an MgO barrier. However, the SIS junctions using a CaF{sub 2} barrier showed a fairly large I{sub c}R{sub N} value at 4.2 K over 1 mV and also exhibited finite Josephson current up to almost the film's T{sub c} (∼30 K). The RHEED observation revealed that top MgB{sub 2} electrodes grow well on a CaF{sub 2} barrier.

  15. Anomalous vortex dynamics in YNi{sub 2}B{sub 2}C

    Energy Technology Data Exchange (ETDEWEB)

    Okuma, S., E-mail: sokuma@o.cc.titech.ac.j [Research Center for Low Temperature Physics, Tokyo Institute of Technology, 2-12-1, Ohokayama, Meguro-ku, Tokyo 152-8551 (Japan); Ichimura, T. [Research Center for Low Temperature Physics, Tokyo Institute of Technology, 2-12-1, Ohokayama, Meguro-ku, Tokyo 152-8551 (Japan); Takeya, H.; Hirata, K. [National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2009-10-15

    We report on measurements of current-voltage (I-V) characteristics for YNi{sub 2}B{sub 2}C single crystals with weak pinning in various fields at 7.6 K. We find nonmonotonic, N-shaped I-V curves in a certain field region deep in the vortex solid phase. This behavior is anomalous, since there exists an intermediate I region where flow voltage V shows a decrease with increasing I (a driving force). While the exact nature remains unknown, this phenomenon suggests vortex motion (driving I) induced pinning.

  16. Unusual pinning induced by vortex motion in YNi{sub 2}B{sub 2}C

    Energy Technology Data Exchange (ETDEWEB)

    Okuma, S., E-mail: sokuma@o.cc.titech.ac.j [Research Center for Low Temperature Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan); Ichimura, T. [Research Center for Low Temperature Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan); Takeya, H.; Hirata, K. [National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2010-12-15

    We present measurements of current-voltage (I-V) characteristics and voltage noise S{sub V} generated by current-driven vortices for a YNi{sub 2}B{sub 2}C single crystal with weak-pinning. Nonmonotonic, N-shaped I-V curves are observed deep in the vortex-solid phase. In the intermediate I region where the unusual negative dV/dI is observed, S{sub V} exhibits a sharp peak. The result suggests vortex-motion-induced dynamic pinning.

  17. Thermal expansion and magnetostriction of superconducting URu{sub 2}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    van Dijk, N.H.; de Visser, A.; Franse, J.J.M.; Menovsky, A.A. [Van der Waals-Zeeman Laboratory, University of Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam (Netherlands)

    1995-05-01

    Dilatation measurements have been performed on a single-crystalline sample of the heavy-fermion superconductor URu{sub 2}Si{sub 2} ({ital T}{sub {ital c}}=1.2 K). Thermal-expansion measurements in combination with specific-heat data reveal a thermal electronic Grueneisen parameter of {Gamma}{sub {ital T}}=27. A comparison with the magnetic electronic Grueneisen parameter derived from the magnetostriction, {Gamma}{sub {ital B}}=26, points to a single energy scale. The measured magnetostriction is strongly anisotropic with a peculiar hysteresis. Close to the upper critical field, a change of sign in the magnetostrictive hysteresis is observed.

  18. Anisotropy of the critical field in CeCu/sub 2/Si/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Aliev, F.G.; Brandt, N.B.; Moshchalkov, V.V.; Zalyalyutdinov, M.K.; Lutsiv, R.V.; Yasnitskii, R.I.; Chudinov, S.M.

    1985-05-25

    An anisotropy (approx.170%) of the derivative of the upper critical field at T = T/sub c/ has been observed in the compound CeCu/sub 2/Si/sub 2/ during rotation of H in a plane near the basis plane. This anisotropy indicates that the superconducting gap may vanish along a line on the Fermi surface in this compound, in which a superconductivity arises in a heavy-fermion system at pressures p> or approx. =1 kbar. The anisotropy disappears at p>9 kbar.

  19. Superconductivity of CeCu/sub 2/Si/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Aliev, F.G.; Brandt, N.B.; Lutsiv, R.V.; Moshchalkov, V.V.; Chudinov, S.M.

    1982-05-20

    Single crystals of CeCu/sub 2/Si/sub 2/ are not superconductors at T> or =0.05 K and at standard pressure, in contrast with polycrystalline samples, but they go superconducting when compressed. Their superconductivity has an anomalously large ratio H/sub C//sup 2/(0)/T/sub C/(0)approx. = 38 kOe/K and a derivative H/sub c/2/dT(T = T/sub c/(0) approx. =140 kOe/K.

  20. CO{sub 2} storage in Sweden; CO{sub 2}-lagring i Sverige

    Energy Technology Data Exchange (ETDEWEB)

    Ekstroem, Clas; Andersson, Annika; Kling, Aasa; Bernstone, Christian [Vattenfall Utveckling AB, Stockholm (Sweden); Carlsson, Anders; Liljemark, Stefan; Wall, Caroline [SwedPower AB, Stockholm (Sweden); Erstedt, Thomas; Lindroth, Maria [Carl Bro Energikonsult AB, Malmoe (Sweden); Tengborg, Per [FB Engineering AB, Goeteborg (Sweden); Edstroem, Mikael [SGU, Uppsala (Sweden)

    2004-07-01

    This study considers options, that could be feasible for Sweden, to transport and geologically store CO{sub 2}, providing that technology for electricity production with CO{sub 2} capture will be available in the future and also acceptable from cost- and reliability point of view. As a starting point, it is assumed that a new 600-1000 MW power plant, fired with coal or natural gas, will be constructed with CO{sub 2} capture and localised to the Stockholm, Malmoe or Goeteborg areas. Of vital importance for storage of carbon dioxide in a reservoir is the possibility to monitor its distribution, i.e. its migration within the reservoir. It has been shown in the SACS-project that the distribution of carbon dioxide within the reservoir can be monitored successfully, mainly by seismic methods. Suitable geologic conditions and a large storage potential seems to exist mainly in South West Scania, where additional knowledge on geology/hydrogeology has been obtained since the year 2000 in connection to geothermal energy projects, and in the Eastern part of Denmark, bordering on South West Scania. Storage of carbon dioxide from the Stockholm area should not be excluded, but more studies are needed to clarify the storage options within this area. The possibilities to use CO{sub 2} for enhanced oil recovery, EOR, in i.a. the North Sea should be investigated, in order to receive incomes from the CO{sub 2} and shared costs for infrastructure, and by this also make the CO{sub 2} regarded as a trading commodity, and thereby achieving a more favourable position concerning acceptance, legal issues and regulations. The dimensions of CO{sub 2}-pipelines should be similar to those for natural natural gas, although regarding some aspects they have different design and construction prerequisites. To obtain cost efficiency, the transport distances should be kept short, and possibilities for co-ordinated networks with short distribution pipelines connected to common main pipelines, should be

  1. Fundamental and clinical studies on the measurement of. beta. /sub 2/-microglobulin using Dainabot. beta. /sub 2/-micro RIA kit

    Energy Technology Data Exchange (ETDEWEB)

    Sugimura, Hidekazu; Iino, Yuko; Sakata, Hiroyuki; Kihara, Kazuhiro; Satoh, Kunio; Demura, Hiroshi; Kawaguchi, Hiroshi; Odagiri, Reiko

    1987-06-01

    A commercial simple one-step assay system for ..beta../sub 2/-microglobulin (..beta../sub 2/-MG), Dainabot ..beta../sub 2/-MG radioimmunoassay (RIA) kit, was fundamentally examined for incubation, recovery, dilution, reproducibility, and correlation with the other assay system. The RIA kit was satisfactory enough to use it routinely. Normal upper limits for ..beta../sub 2/-MG in serum (S-..beta../sub 2/-MG) and urine (U-..beta../sub 2/-MG) were 1.92 mg/l and 460 ..mu..g/l, respectively. Decreased values of two-hr creatinine clearance were inversely correlated with increased values of serum creatinine, blood urea nitrogen, and S-..beta../sub 2/-MG. U-..beta../sub 2/-MG tended to increase with decreasing values of 15-min phenolsulfonphthalein. In the case of renal tubular acidosis, Fanconi's syndrome, Wilson's disease, hydronephrosis, and pyelonephritis, S-..beta../sub 2/-MG was normal and U-..beta../sub 2/-MG was abnormal. Since S-..beta../sub 2/-MG and U-..beta../sub 2/-MG are recognized as reflecting glomerular function and renal tubular disturbances, respectively, concurrent measurements of S-..beta../sub 2/-MG and U-..beta../sub 2/-MG may be of clinical value. (Namekawa, K.).

  2. Characterization of NO[sub 2] and SO[sub 2] removals in a spray dryer/baghouse system

    Energy Technology Data Exchange (ETDEWEB)

    O' Dowd, W.J.; Markussen, J.M.; Pennline, H.W. (Dept. of Energy, Pittsburgh, PA (United States)); Resnik, K.P. (Gilbert/Commonwealth, Inc., Library, PA (United States))

    1994-11-01

    Oxidation of NO to NO[sub 2] has been proposed as a method for enhancing NO[sub x] removals in conventional flue gas desulfurization (FGD) processes. This experimental investigation characterizes the removals of NO[sub 2] and SO[sub 2] in a 1.1 m[sup 3](standard)/min spray dryer/baghouse system. Flue gas was generated by burning a No. 2 fuel oil, which was subsequently spiked upstream of the spray dryer with NO[sub 2] or SO[sub 2] or both. Lime slurry was injected via a rotary atomizer into the spray dryer. Variables studied include the approach to the adiabatic saturation temperature, stoichiometric ratio, SO[sub 2] concentration, and NO[sub 2] concentration. Significant quantities of NO[sub 2] are scrubbed in this system, and over half of the total removal (at inlet NO[sub 2] > 400 ppm) occurs in the baghouse. Increasing NO[sub 2] concentrations enhance the amount of NO[sub x] removed in the system. Also, the presence of significant quantities of NO[sub 2] enhances the baghouse SO[sub 2] removal. Although up to 72% NO[sub 2] removals were obtained, concentrations of NO[sub 2] that exited the system were greater than 50 ppm for all conditions investigated.

  3. Thermoelectric sintered glass-ceramics with a Bi{sub 2}Sr{sub 2}Co{sub 2}O{sub x} phase

    Energy Technology Data Exchange (ETDEWEB)

    Lingner, Julian [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik, Mainz (Germany); SCHOTT AG, Material Development, Mainz (Germany); Funahashi, Ryoji; Combe, Emmanuel [National Institute of Advanced Industrial Science and Technology, Osaka (Japan); Letz, Martin [SCHOTT AG, Material Development, Mainz (Germany); Jakob, Gerhard [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik, Mainz (Germany)

    2015-07-15

    Glass-ceramic materials containing Bi{sub 2}Sr{sub 2}Co{sub 2}O{sub x} crystals with plate-like structures are prepared by a melting process and a subsequent sintering step after manual quenching. The chemical starting compositions of the samples are Bi{sub 2}Sr{sub 2}Co{sub 2}O{sub x} (BSC222), Bi{sub 1.8}Sr{sub 2}Co{sub 2}O{sub x} (Bi1.8) and Bi{sub 2}Sr{sub 2}Co{sub 1.7}O{sub x} (Co1.7). All three samples are p-type conductors. The electric properties of Seebeck coefficient S and electrical resistivity ρ show only a slight dependence on chemical composition. The Seebeck values increase with increasing temperature, and at T = 873 K, they reach S = 180, 176 and 167 μV/K, respectively. The electrical resistivity slightly decreases with temperature for two samples and increases for the Co1.7 sample. The thermal conductivity for all measured samples at this temperature is around κ = 0.8 W/(m K). The figure of merit ZT increases with temperature for all samples. The materials reach a ZT value of 0.03 at T = 873 K. (orig.)

  4. Preparation and thermoluminescent properties of TiO{sub 2}; Preparacion y propiedades termoluminiscentes del TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Azorin V, J.C.; Calderon A, J.A.; Rivera M, T. [CICATA-Legaria, IPN, Av. Legaria 694, 11500 Mexico D.F. (Mexico); Azorin N, J. [UAM-I, 09340 Mexico D.F. (Mexico)

    2005-07-01

    At the present, studies trending to the development of new TL materials as well as for their characterization, their use in the dosimetry of the ionizing radiation have been carried out in the entire world. Among these new materials, the doped metal oxides with rare earths is those more popular. The main objective of this work is to study the thermoluminescent properties of the titanium oxide (TiO{sub 2}) doped with Europium (Eu{sup 3+}) and its possible application in the dosimetry of the ionizing radiation, taking in consideration some external agents such as: preparation method, doped concentration, thermal treatments of re cooked, thermal treatments of erased, etc. The results indicate that the TL material of TiO{sub 2} presents TL response when being exposed to radiations with energy from 600 keV (gammas of the {sup 137} Cs until 2.28 MeV corresponding to the beta particles of the {sup 90}Sr/{sup 90}Y and that the material without doping presents TL properties more adequate for dosimetry than the doped material with Europium. (Author)

  5. Preparation of UO{sub 2}, ThO{sub 2} and (Th,U)O{sub 2} pellets from photochemically-prepared nano-powders

    Energy Technology Data Exchange (ETDEWEB)

    Pavelková, Tereza [Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Břehová 7, 115 19 Praha 1 (Czech Republic); Čuba, Václav, E-mail: vaclav.cuba@fjfi.cvut.cz [Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Břehová 7, 115 19 Praha 1 (Czech Republic); Visser-Týnová, Eva de [Nuclear Research and Consultancy Group (NRG), Research & Innovation, Westerduinweg 3, 1755 LE Petten (Netherlands); Ekberg, Christian [Nuclear Chemistry/Industrial Materials Recycling, Chalmers University of Technology, SE-412 96 Göteborg (Sweden); Persson, Ingmar [Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala (Sweden)

    2016-02-15

    Photochemically-induced preparation of nano-powders of crystalline uranium and/or thorium oxides and their subsequent pelletizing has been investigated. The preparative method was based on the photochemically induced formation of amorphous solid precursors in aqueous solution containing uranyl and/or thorium nitrate and ammonium formate. The EXAFS analyses of the precursors shown that photon irradiation of thorium containing solutions yields a compound with little long-range order but likely “ThO{sub 2} like” and the irradiation of uranium containing solutions yields the mixture of U(IV) and U(VI) compounds. The U-containing precursors were carbon free, thus allowing direct heat treatment in reducing atmosphere without pre-treatment in the air. Subsequent heat treatment of amorphous solid precursors at 300–550 °C yielded nano-crystalline UO{sub 2}, ThO{sub 2} or solid (Th,U)O{sub 2} solutions with high purity, well-developed crystals with linear crystallite size <15 nm. The prepared nano-powders of crystalline oxides were pelletized without any binder (pressure 500 MPa), the green pellets were subsequently sintered at 1300 °C under an Ar:H{sub 2} (20:1) mixture (UO{sub 2} and (Th,U)O{sub 2} pellets) or at 1600 °C in ambient air (ThO{sub 2} pellets). The theoretical density of the sintered pellets varied from 91 to 97%. - Highlights: • Photochemically prepared UO{sub 2}/ThO{sub 2} nano-powders were pelletized. • The nano-powders of crystalline oxides were pelletized without any binder. • Pellets were sintered at 1300 °C (UO{sub 2} and (Th,U)O{sub 2}) or 1600 °C (ThO{sub 2} pellets). • The theoretical density of the sintered pellets varies from 91 to 97%.

  6. Pulsed cathodoluminescence and Raman spectra of MoS{sub 2} and WS{sub 2} nanocrystals and their combination MoS{sub 2}/WS{sub 2} produced by self-propagating high-temperature synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Bozheyev, Farabi, E-mail: farabi.bozheyev@gmail.com [Institute of High Technology Physics, National Research Tomsk Polytechnic University, 30 Lenin Ave., 634050 Tomsk (Russian Federation); National Nanolaboratory, al-Farabi Kazakh National University, 71 al-Farabi Ave., 050000 Almaty (Kazakhstan); Nazarbayev University Research and Innovation System, 53 Kabanbay Batyr St., 010000 Astana (Kazakhstan); Valiev, Damir [Institute of High Technology Physics, National Research Tomsk Polytechnic University, 30 Lenin Ave., 634050 Tomsk (Russian Federation); Nemkayeva, Renata [National Nanolaboratory, al-Farabi Kazakh National University, 71 al-Farabi Ave., 050000 Almaty (Kazakhstan)

    2016-02-29

    Molybdenum and tungsten disulfide nanoplates were produced by self-propagating high-temperature synthesis in argon atmosphere. This method provides an easy way to produce MoS{sub 2} and WS{sub 2} from nanoplates up to single- and several layers. The Raman peak intensities corresponding to in-plane E{sup 1}{sub 2g} and out-of-plane A{sub 1g} vibration modes and their shifts strongly depend on the thicknesses of the MoS{sub 2} and WS{sub 2} platelets indicating size-dependent scaling laws and properties. An electron beam irradiation of MoS{sub 2} and WS{sub 2} powders leads to an occurrence of pulsed cathodoluminescence (PCL) spectra at 575 nm (2.15 eV) and 550 nm (2.25 eV) characteristic to their intrinsic band gaps. For the combination of MoS{sub 2} and WS{sub 2} nanopowders, a PCL shoulder at 430 nm (2.88 eV) was observed, which is explained by the radiative electron-hole recombination at the MoS{sub 2}/WS{sub 2} grain boundaries. The luminescence decay kinetics of the MoS{sub 2}/WS{sub 2} nanoplates appears to be slower than for individual MoS{sub 2} and WS{sub 2} platelets due to a spatial separation of electrons and holes at MoS{sub 2}/WS{sub 2} junction resulting in extension of recombination time.

  7. Solar degradation of 5-amino-6-methyl-2-benzimidazolone by TiO{sub 2} and iron (III) catalyst with H{sub 2}O{sub 2} and O{sub 2} as electron acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Sarria, V.; Peringer, P.; Pulgarin, C. [Swiss Federal Institute of Technology, Lausanne (Switzerland). Institute of Environmental Science and Technology, Laboratory for Environmental Biotechnology; Caceres, J.; Blanco, J.; Malato, S. [Plataforma Solar de Almeria, Tabernas (Spain)

    2004-05-01

    Wastewater containing mainly 5-amino-6-methyl-2-benzimidazolone (AMBI), used in the manufacture of dyes, was characterized as bio-recalcitrant by means of different biodegradability tests. In order to enhance the biodegradability of this important pollutant, solar photocatalytic degradation methods were explored. The systems light/TiO{sub 2}/O{sub 2}, light/TiO{sub 2}/H{sub 2}O{sub 2}, light/Fe{sup 3+}/O{sub 2} and lightFe{sup 3+}/H{sub 2}O{sub 2} were compared under direct sunlight at the Plataforma Solar de Almeria (Spain), using a Compound Parabolic Collector (CPC). The iron photo-assisted systems exhibited the most interesting behaviour, from the kinetic and engineering points of view, especially if their combination (as pre-treatment) with a biological process is considered. To compare the efficiency of these systems, the evolution of the following parameters were studied: (a) the dissolved organic carbon and initial compound concentration, (b) the toxicity, and (c) the biodegradability of treated solution. At lab scale, using a solar lamp, the degradation rate of the system light/Fe{sup 3+}/H{sub 2}O{sub 2} was two times higher than the system light/Fe{sup 3+}/O{sub 2} but this last system does not need H{sub 2}O{sub 2} addition, improving the economical requirements of the system. (author)

  8. Solar degradation of 5-amino-6-methyl-2-benzimidazolone by TiO{sub 2} and iron(III) catalyst with H{sub 2}O{sub 2} and O{sub 2} as electron acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Sarria, Victor; Peringer, Paul; Caceres, Julia; Blanco, Julian; Malato, Sixto; Pulgarin, Cesar

    2004-05-01

    Wastewater containing mainly 5-amino-6-methyl-2-benzimidazolone (AMBI), used in the manufacture of dyes, was characterized as bio-recalcitrant by means of different biodegradability tests. In order to enhance the biodegradability of this important pollutant, solar photocatalytic degradation methods were explored. The systems light/TiO{sub 2}/O{sub 2}, light/TiO{sub 2}/H{sub 2}O{sub 2}, light/Fe{sup 3+}/O{sub 2} and light/Fe{sup 3+}/H{sub 2}O{sub 2} were compared under direct sunlight at the Plataforma Solar de Almeria (Spain), using a Compound Parabolic Collector (CPC). The iron photo-assisted systems exhibited the most interesting behaviour, from the kinetic and engineering points of view, especially if their combination (as pre-treatment) with a biological process is considered. To compare the efficiency of these systems, the evolution of the following parameters were studied: (a) the dissolved organic carbon and initial compound concentration, (b) the toxicity, and (c) the biodegradability of treated solution. At lab scale, using a solar lamp, the degradation rate of the system light/Fe{sup 3+}/H{sub 2}O{sub 2} was two times higher than the system light/Fe{sup 3+}/O{sub 2} but this last system does not need H{sub 2}O{sub 2} addition, improving the economical requirements of the system.

  9. Synthesis of cerium oxide (CeO{sub 2}) nanoparticles using simple CO-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Farahmandjou, M.; Zarinkamar, M.; Firoozabadi, T. P., E-mail: farahamndjou@iauvaramin.ac.ir [Islamis Azad University, Varamin-Phisva Branch, Department of Physics, Varamin (Iran, Islamic Republic of)

    2016-11-01

    Synthesis of cerium oxide (CeO{sub 2}) nanoparticles was studied by new and simple co-precipitation method. The cerium oxide nanoparticles were synthesized using cerium nitrate and potassium carbonate precursors. Their physicochemical properties were characterized by high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (Sem), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (Ftir) and UV-Vis spectrophotometer. XRD pattern showed the cubic structure of the cerium oxide nanoparticles. The average particle size of CeO{sub 2} was around 20 nm as estimated by XRD technique and direct HRTEM observations. The surface morphological studies from Sem and Tem depicted spherical particles with formation of clusters. The sharp peaks in Ftir spectrum determined the existence of CeO{sub 2} stretching mode and the absorbance peak of UV-Vis spectrum showed the bandgap energy of 3.26 eV. (Author)

  10. Direct gas-phase synthesis of single-phase {beta}-FeSi{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bywalez, Robert, E-mail: robert.bywalez@uni-due.de; Orthner, Hans; Mehmedovic, Ervin [University of Duisburg-Essen, IVG, Institute for Combustion and Gas Dynamics - Reactive Fluids (Germany); Imlau, Robert; Kovacs, Andras; Luysberg, Martina [Forschungszentrum Juelich, Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute 5 (Germany); Wiggers, Hartmut [University of Duisburg-Essen, IVG, Institute for Combustion and Gas Dynamics - Reactive Fluids (Germany)

    2013-09-15

    For the first time, phase-pure {beta}-FeSi{sub 2} nanoparticles were successfully produced by gas-phase synthesis. We present a method to fabricate larger quantities of semiconducting {beta}-FeSi{sub 2} nanoparticles, with crystallite sizes between 10 and 30 nm, for solar and thermoelectric applications utilizing a hot-wall reactor. A general outline for the production of those particles by thermal decomposition of silane and iron pentacarbonyl is provided based on kinetic data. The synthesized particles are investigated by X-ray diffraction and transmission electron microscopy, providing evidence that the as-prepared materials are indeed {beta}-FeSi{sub 2}, while revealing morphological characteristics inherent to the nanoparticles created.

  11. Optical absorption properties of Ag/SiO sub 2 composite films induced by gamma irradiation

    CERN Document Server

    Pan, A L; Yang, Z P; Liu, F X; Ding, Z J; Qian, Y T

    2003-01-01

    Mesoporous SiO sub 2 composite films with small Ag particles or clusters dispersed in them were prepared by a new method: first the matrix SiO sub 2 films were prepared by the sol-gel process combined with the dip-coating technique; then they were soaked in AgNO sub 3 solutions; this was followed by irradiation with gamma-rays at room temperature and ambient pressure. The structure of these films was examined by high-resolution transmission electron microscopy, and their optical absorption spectra were examined. It has been shown that the Ag particles grown within the porous SiO sub 2 films are very small and are highly dispersed. On increasing the soaking concentration and subjecting the samples to an additional annealing, a different peak-shift effect for the surface plasmon resonance was observed in the optical absorption measurement. Possible mechanisms of this behaviour are discussed in this paper.

  12. Cyclic CO{sub 2} capture performance of carbide slag. Parametric study

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Deng-Feng [Chinese Academy of Sciences, Beijing (China). State Key Lab. of Multi-Phase Complex Systems; Chinese Academy of Sciences, Beijing (China). Graduate Univ.; Zhao, Peng-Fei; Li, Song-Geng; Song, Wen-Li [Chinese Academy of Sciences, Beijing (China). State Key Lab. of Multi-Phase Complex Systems

    2013-07-01

    In this work, CO{sub 2} capture performance of carbide slag has been investigated in a thermogravimetric analyzer (TGA). Effects of operation parameters including particle size, reaction temperature and reaction duration on CO{sub 2} capture capacity were studied. The experimental results indicate that the increase of particle size ranging from 80 to 180 {mu}m has a positive effect on the CO{sub 2} capture capacity of carbide slag. The sorbent reactivity decreases with an increase of calcination temperature. The prolonged exposure to carbonation conditions has a beneficial effect on sorbent behavior as a function of the number of calcination/carbonation cycles; however, the duration in the calcination step has little effect. Based on the experimental results, the reaction rate constant of carbonation reaction is obtained from Jander equation. It is found that it decreases with the increasing cycles.

  13. Preparation of SiO{sub 2}/TiO{sub 2} and TiO{sub 2}/TiO{sub 2} micropattern and their effects on platelet adhesion and endothelial cell regulation

    Energy Technology Data Ex