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Sample records for nano neodymium oxide

  1. Preparation and characterization of a sandwiched target of enriched neodymium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, S.; Kabiraj, D.; Avasthi, D.K. [Nucl. Sci. Centre, New Delhi (India)

    1997-09-21

    The preparation of enriched neodymium oxide targets sandwiched between two carbon foils is discussed. The concentration of oxygen in a prepared target was measured using low-angle Rutherford scattering and elastic recoil detection analysis ERDA technique. The analysis indicated that the prepared target had 31 at.% of oxygen as compared to the expected concentration of 60 at.% relative to neodymium. It shows that neodymium oxide loses oxygen during evaporation. (orig.). 4 refs.

  2. Interfacial Reactions and Cubic Neodymium Oxide Formation in Low Dispersed Nd2O3-SiO2 System by Wet Chemical Method

    Institute of Scientific and Technical Information of China (English)

    S. Duhan; P. Aghamkar

    2009-01-01

    Neodymium (binary oxide) powders are synthesized by a solgel technique. Prepared powders are heat treated under different temperature for different time duration and obtained nanostructure of Nd. Metal particle have diameters in the range 7.8-21.6nm. It is found that the heat treatment plays an important role to produce different structure of Nd-doped silica matrix. The peak position shifts to lower angle as the size of the nano metal oxide particles size increases.

  3. Synthesis and characterization of composites of mixed oxides of iron and neodymium in polymer matrix of aniline–formaldehyde

    Indian Academy of Sciences (India)

    Sajdha; H N Sheikh; B L Kalsotra; N Kumar; S Kumar

    2011-07-01

    Nanocomposites of mixed oxides of iron and neodymium in polymer matrix of anilineformaldehyde are reported. The composites have been obtained by treating the aqueous solution of aniline, hydrochloric acid and formaldehyde with halide of iron and neodymium oxide. The infra-red spectra show broad peaks at ∼ 590 cm-1 and at ∼ 610 cm-1 due to the presence of oxides of both iron and neodymium. In heated samples, the absorption peaks due to metal oxides are better resolved. A broad and strong peak in XRD spectra at 2 value of 35.69920 corresponds to spinel -Fe2O3. 57Fe Mössbauer spectrum for unheated sample gives Mössbauer parameters, i.e. isomer shift (), quadrupole splitting ( ) and effective magnetic field (Heff). Transmission electron microscopy (TEM) micrographs reveal well dispersed particles at different magnifications. Vibrating sample magnetometry (VSM) studies indicate that the ferrite nanoparticles exhibit characteristics of ferromagnetism.

  4. Functional Hybrid Nano-Oxides

    Science.gov (United States)

    2015-10-26

    ABSTRACT This project was dedicated to investigate and engineer novel properties of oxide based materials , nanostructures and devices with properties that...mechanism for the metal-insulator transition and it also opens up the possibility for the preparation of unique nanostructured materials . A second major...spare time since the funding ended before. Development of novel synthesis and characterization methods in area of Nano-Oxides paved the way to

  5. Dielectric and piezoelectric properties of neodymium oxide doped lead zirconate titanate ceramics

    Indian Academy of Sciences (India)

    Janardan Singh; N C Soni; S L Srivastava

    2003-06-01

    The dielectric and electromechanical properties of lead zirconate titanate [Pb(Zr, Ti)O3] ceramic added with neodymium oxide have been systematically studied employing the vector impedance spectroscopic (VIS) technique. The specimens were prepared using the mixed oxide route by adding different mol% of Nd2O3 (0.1 to 7 mol%) in [Pb(Zr, Ti)O3] near morphotropic phase boundary. Piezoelectric equivalent circuit parameters , , $C_a$ in series and $C_b$ in parallel have been determined by simulating /Z/ and plots. Electromechanical coupling coefficients and strain constants for the radial modes show a peak at about 3 mol%, the dielectric constant peaks at about 1 mol% and voltage constants peak at about 0.75 mol% of Nd2O3.

  6. Synthesis and characterization of nano-structured perovskite type neodymium orthoferrite NdFeO3

    Directory of Open Access Journals (Sweden)

    Mostafa Yousefi

    2017-01-01

    Full Text Available In this investigation, neodymium orthoferrite (NdFeO3 nanoparticles has been synthesized through ultrasonic method in the presence of octanoic acid as surfactant. This method comparing to the other methods is very fast and it does not need high temperatures during the reaction. The spherical NdFeO3 nanoparticles with an average particles size of about 40 nm can be obtained at a relatively high calcination temperature of 800 °C for 4 h. Also, product obtained by this method are uniform in both morphology and particles size. The phase composition, morphology, lattice parameters and size of particles in these product are characterized by Fourier transform infrared (FT-IR spectroscopy, X-ray diffraction (XRD scanning electron microscopy (SEM and energy dispersive X-ray spectrometer (EDX. The XRD analysis reveals only the pattern corresponding to perovskite type NdFeO3 which crystallizes in the orthorhombic structure. Energy dispersive X-ray analysis confirms the elemental compositions of the synthesized material.

  7. Nano-rods of zinc oxide in nano-graphene

    Science.gov (United States)

    Ortiz, Pedro; Chavira, Elizabeth; Monroy, Marel; Elizalde, José; Santiago, Patricia; Sato, Roberto; Tejeda, Adriana; González, Guillermina; Novelo, Omar; Flores, Carlos

    2014-03-01

    It's of great interest to study the devices based on nano-ZnO and graphene, for their electromagnetic and optical properties to increase the efficiency of solar cells. The graphene multilayers synthesis was done by mechanosynthesis, grinding in a mechanical agate mortar. The zinc oxide nano-rods were synthesized from zinc acetate dihydrate, Ace, (Sigma Aldrich) and ethylene diamine, En, (Sigma Aldrich) with a 1:2 ratio of reagents En/Ace. The ZnO nano-rods in nano-tubes graphene were obtained by mechanosynthesis. The X-ray powder diffraction, shows the shift of C with PDF 12-0212 and ZnO, Zincite PDF 36-1451, both with hexagonal unit cell. The grain size and morphology of graphene (multilayers and nano-tubes), ZnO nano-rods and ZnO-graphene mixture (multilayers, nano-tubes) were observed by scanning electron microscope. Transmission electron microscope, corroborates shown in SEM. Raman spectroscopy, shows the shift of multilayer graphene and the ZnO nano-rods. In photoluminescence measurements, observe the change in intensity in the band defects. Magnetic properties characterization was carried out by Vibrating Sample Magnetometry. We conclude that graphite multilayers dislocated by cutting efforts, forming graphene nano-tubes and encapsulated ZnO nano-rods within graphene.

  8. Nano cobalt oxides for photocatalytic hydrogen production

    KAUST Repository

    Mangrulkar, Priti A.

    2012-07-01

    Nano structured metal oxides including TiO 2, Co 3O 4 and Fe 3O 4 have been synthesized and evaluated for their photocatalytic activity for hydrogen generation. The photocatalytic activity of nano cobalt oxide was then compared with two other nano structured metal oxides namely TiO 2 and Fe 3O 4. The synthesized nano cobalt oxide was characterized thoroughly with respect to EDX and TEM. The yield of hydrogen was observed to be 900, 2000 and 8275 mmol h -1 g -1 of photocatalyst for TiO 2, Co 3O 4 and Fe 3O 4 respectively under visible light. It was observed that the hydrogen yield in case of nano cobalt oxide was more than twice to that of TiO 2 and the hydrogen yield of nano Fe 3O 4 was nearly four times as compared to nano Co 3O 4. The influence of various operating parameters in hydrogen generation by nano cobalt oxide was then studied in detail. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  9. Plasma electrolytic oxidation coating on AZ91 magnesium alloy modified by neodymium and its corrosion resistance

    Science.gov (United States)

    Song, Y. L.; Liu, Y. H.; Yu, S. R.; Zhu, X. Y.; Wang, Q.

    2008-03-01

    Ceramic coatings on the surfaces of Mg-9Al-1Zn (AZ91) magnesium alloy and Mg-9Al-1Zn-1Nd magnesium alloy (AZ91 magnesium alloy modified by neodymium, named as AZ91Nd in this paper) are synthesized in aluminate electrolyte by plasma electrolytic oxidation (PEO) process, respectively. X-ray diffraction and X-ray photoelectron spectroscopy analyses show the PEO coating on the Mg-9Al-1Zn-1Nd alloy comprises not only MgO and Al 2O 3, which are found in the coating on the AZ91 alloy, but also a trace amount of Nd 2O 3. Microstructure observations indicate the addition of Nd can decrease the sizes of β phases and form Al 2Nd intermetallics in the AZ91 alloy. The fine β phases can effectively restrain the formation of unclosed-holes and greatly decrease the sizes of pores in the coating during the PEO process. In addition, the Al 2Nd intermetallics can be completely covered due to the lateral growth of the PEO coatings formed on the α and β phases. As a result, the coating on the AZ91Nd alloy possesses a dense microstructure compared with that on the AZ91 alloy. The following corrosion tests indicate the corrosion resistance of the PEO coating on the AZ91Nd alloy is evidently higher than that of the PEO coating on the AZ91 alloy.

  10. Properties of Copper Doped Neodymium Nickelate Oxide as Cathode Material for Solid Oxide Fuel Cells

    OpenAIRE

    Lee Kyoung-Jin; Choe Yeong-Ju; Hwang Hae-Jin

    2016-01-01

    Mixed ionic and electronic conducting K2NiF4-type oxide, Nd2Ni1-xCuxO4+δ (x=0~1) powders were synthesized by solid state reaction technique and solid oxide fuel cells consisting of a Nd2Ni1-xCuxO4+δ cathode, a Ni-YSZ anode and ScSZ as an electrolyte were fabricated. The effect of copper substitution for nickel on the electrical and electrochemical properties was examined. Small amount of copper doping (x=0.2) resulted in the increased electrical conductivity and decreased polarization resista...

  11. Catalysis on Interface of Nano-oxide and Nano-zeolite

    Institute of Scientific and Technical Information of China (English)

    K.Ito; F.Jan; S.Asaoka

    2007-01-01

    1 Results The catalysts which can efficiently hydro-reform higher n-paraffin to lower isoparaffins for environmentally-friendly gasoline were studied. The catalysts were examined by the conversion of n-hexadecane, n-C16H34 to i-C6H14—i-C10H22.The tri-modally nano-porous catalysts composed of (Ni-Mo)/[γ-Al2O3], nano-oxide, and nano-crystalline zeolite had some active and selective performance because of the interface between nano-oxide and nano-zeolite. The catalyst composed of nano-crystalline MFI or BE...

  12. Development of an empirical kinetic model for sonocatalytic process using neodymium doped zinc oxide nanoparticles.

    Science.gov (United States)

    Khataee, Alireza; Vahid, Behrouz; Saadi, Shabnam; Joo, Sang Woo

    2016-03-01

    The degradation of Acid Blue 92 (AB92) solution was investigated using a sonocatalytic process with pure and neodymium (Nd)-doped ZnO nanoparticles. The nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The 1% Nd-doped ZnO nanoparticles demonstrated the highest sonocatalytic activity for the treatment of AB92 (10 mg/L) with a degradation efficiency (DE%) of 86.20% compared to pure ZnO (62.92%) and sonication (45.73%) after 150 min. The results reveal that the sonocatalytic degradation followed pseudo-first order kinetics. An empirical kinetic model was developed using nonlinear regression analysis to estimate the pseudo-first-order rate constant (kapp) as a function of the operational parameters, including the initial dye concentration (5-25 mg/L), doped-catalyst dosage (0.25-1 g/L), ultrasonic power (150-400 W), and dopant content (1-6% mol). The results from the kinetic model were consistent with the experimental results (R(2)=0.990). Moreover, DE% increases with addition of potassium periodate, peroxydisulfate, and hydrogen peroxide as radical enhancers by generating more free radicals. However, the addition of chloride, carbonate, sulfate, and t-butanol as radical scavengers declines DE%. Suitable reusability of the doped sonocatalyst was proven for several consecutive runs. Some of the produced intermediates were also detected by GC-MS analysis. The phytotoxicity test using Lemna minor (L. minor) plant confirmed the considerable toxicity removal of the AB92 solution after treatment process.

  13. Synthesis of Neodymium-Doped Yttrium Aluminum Garnet (Nd∶YAG) Nano-Sized Powders by Low Temperature Combustion

    Institute of Scientific and Technical Information of China (English)

    Zhang Huashan; Su Chunhui; Han Hui; Hou Zhaoxia

    2005-01-01

    The homogeneously dispersed, less agglomerated (Nd0.01Y0.99)3Al5O12 nano-sized powders were synthesized by the low temperature combustion (LCS), using Nd2O3, Y2O3, Al(NO3)3·9H2O, ammonia water and citric acid as starting materials. This method effectively solves the problems caused by solid-state reaction at high temperature and hard agglomerates brought by the chemical precipitation method. The powders were characterized by TG-DTA, XRD, FT-IR, TEM respectively and the photoluminescence (PL) spectra of (Nd0.01Y0.99)3Al5O12 green and sintered ceramic disks were measured. The results show that the forming temperature of YAG crystal phase is 850 ℃ and YAP crystal phase appearing during the calcinations transforms to pure YAG at 1050 ℃. The particle size of the powders synthesized by the LCS is in a range of 20~50 nm depending on the thermal treatment temperatures. The effectively induced cross section (σin) with the value 4.03×10-19 cm2 of (Nd0.01Y0.99)3Al5O12 ceramics is about 44% higher than that of single crystal.

  14. Spectroscopic Properties of Neodymium and Erbium-Doped Magnesium Oxide Ceramics

    Science.gov (United States)

    2015-09-01

    such as YAG and even fluorides (such as yttrium lithium fluoride [LiYF4]), is known to drastically improve (to about an order of magnitude) upon...thermodynamic processes such as single crystal growth. Low-temperature chemical synthesis methods, such as rapid co- precipitation of the mixed oxide...or RE oxide precipitates has not been found. Rather Fig. 5 illustrates one of some commonly observed amorphous features found in the intergranular

  15. Gaseous detonation synthesis and characterization of nano-oxide

    Science.gov (United States)

    Yan, Honghao; Wu, Linsong; Li, Xiaojie; Wang, Xiaohong

    2015-07-01

    Gaseous detonation is a new method of heating the precursor of nanomaterials into gas, and integrating it with combustible gas as mixture to be detonated for the synthesis of nanomaterials. In this paper, the mixed gas of oxygen and hydrogen is used as the source for detonation, to synthesize nano TiO2, nano SiO2 and nano SnO2 through gaseous detonation method, characterization and analysis of the products, it was found that the products from gaseous detonation method were of high purity, good dispersion, smaller particle size and even distribution. It also shows that for the synthesis of nano-oxides, gaseous detonation is universal.

  16. Calculations of thermodynamic data from spectroscopic data for oxides for cerium and neodymium

    Energy Technology Data Exchange (ETDEWEB)

    Sunder, S.; Lemire, R.J

    2000-01-01

    A code to calculate thermodynamic functions of an ideal gas (at 1 atm pressure) from its spectroscopic data using statistical mechanics methods was commissioned, tested and verified. The code was used to calculate the thermodynamic functions for three fission-product oxides, Ce0{sub 2}, Ce{sub 2}0{sub 2} and NdO{sub 2}, for temperatures between 100 K and 3000 K and 0.1 MPa. High-temperature thermodynamic data of fission products are needed to calculate the source terms under accident conditions using fuel safety codes such as CHMWRK and F*A*C*T. (author)

  17. Preparation and chemical characterization of neodymium-doped molybdenum oxide films grown using spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Alfonso, J. E. [Universidad Nacional de Colombia, Departamento de Fisica, Grupo de Ciencia Materiales y Superficies, AA 5997 Bogota DC (Colombia); Moreno, L. C., E-mail: jealfonsoo@unal.edu.co [Universidad Nacional de Colombia, Departamento de Quimica, AA 5997 Bogota DC (Colombia)

    2014-07-01

    We studied the crystalline, morphology, and surface composition of Nd-doped molybdenum oxide films grown on glass slides through spray pyrolysis. After fabrication, the films were subjected to thermal treatment in oxygen for periods ranging from 2 to 20 hours. The films were structurally characterized though X-ray diffraction (XRD), their bulk chemical composition was determined using Energy-Dispersive X-ray analysis (EDX), and their surface composition was determined using X-ray Photoelectron Spectroscopy (XP S). The XRD results show that the films obtained from different dissolution volumes and at substrate temperature of 300 grades C exhibit the characteristics of the oxygen-deficient molybdenum trioxide Mo{sub 9}O{sub 26} phase. The films subjected to different thermal treatments exhibit a mixture of Mo{sub 9}O{sub 26} and Mo{sub 17}O{sub 47} phases. EDX study shows the energy belonging to the L line of Nd. Finally, films doped with Nd and subjected to a thermal treatment of 20 h were analyzed through XP S, showing the binding energies at the crystalline lattice correspond to Nd{sub 2} (MoO{sub 4}){sub 3} and Nd{sub 2}Mo{sub 2}O{sub 7}. (Author)

  18. Contribution of physicochemical characteristics of nano-oxides to cytotoxicity.

    Science.gov (United States)

    Xu, Mingsheng; Fujita, Daisuke; Kajiwara, Shoko; Minowa, Takashi; Li, Xianglan; Takemura, Taro; Iwai, Hideo; Hanagata, Nobutaka

    2010-11-01

    To identify the key physicochemical properties of nano-oxides governing cytotoxicity, we investigate the contribution of the size, shape, morphology, and electronic properties of ten types of insulator (SiO(2), CeO(2) and Al(2)O(3)) and semiconductor (ZnO and CuO) nano-oxides to cytotoxicity using the NIH3T3 and A549 cell lines as models. We find that the shape of the Al(2)O(3) (nanoparticle versus nanowhisker) and the morphology of the SiO(2) (porous versus non-porous nanoparticles) did not have obvious effect on the observed cytotoxicity, and the size of the nano-oxides cannot be regarded as an indicator of cytotoxicity. By contrast, we find that the cell viability exposed to the semiconductor nano-oxides was much lower than that exposed to the insulator nano-oxides. Moreover, the Al-doped ZnO nanoparticle (NP) was more toxic than the non-doped ZnO NP, whereas the Al-doped CuO NP was less toxic than the non-doped CuO NP but more toxic than the Al(2)O(3) NP. Correspondingly, the valence band X-ray photoelectron spectra of the nano-oxides show the density of states of the Al-doped ZnO NP (the Al-doped CuO NP) is higher (lower) than that of the non-doped ZnO NP (the non-doped CuO NP). These results suggest that the electronic properties of nano-oxides may play an important role in the observed cytotoxicity. The results have implications for selectively tailoring the toxic effect and establishing predictive models for the design of various types of nanomaterials with unique properties and for the understanding of interactions between nanomaterials with biological system.

  19. Nano zinc oxide-sodium alginate antibacterial cellulose fibres.

    Science.gov (United States)

    Varaprasad, Kokkarachedu; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Seo, Jongchul

    2016-01-01

    In the present study, antibacterial cellulose fibres were successfully fabricated by a simple and cost-effective procedure by utilizing nano zinc oxide. The possible nano zinc oxide was successfully synthesized by precipitation technique and then impregnated effectively over cellulose fibres through sodium alginate matrix. XRD analysis revealed the 'rod-like' shape alignment of zinc oxide with an interplanar d-spacing of 0.246nm corresponding to the (101) planes of the hexagonal wurtzite structure. TEM analysis confirmed the nano dimension of the synthesized zinc oxide nanoparticles. The presence of nano zinc oxide over cellulose fibres was evident from the SEM-EDS experiments. FTIR and TGA studies exhibited their effective bonding interaction. The tensile stress-strain curves data indicated the feasibility of the fabricated fibres for longer duration utility without any significant damage or breakage. The antibacterial studies against Escherichia coli revealed the excellent bacterial devastation property. Further, it was observed that when all the parameters remained constant, the variation of sodium alginate concentration showed impact in devastating the E. coli. In overall, the fabricated nano zinc oxide-sodium alginate cellulose fibres can be effectively utilized as antibacterial fibres for biomedical applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Influence of niobium, neodymium and praseodymium oxides percentage on the Si{sub 3} N{sub 4} sintering; Influencia da percentagem de niobia, neodimia e praseodimia, na sinterizacao do Si{sub 3} N{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cosme Roberto Moreira da; Martins, Joao Renato Santos; Piorino Neto, Francisco; Melo, Francisco Cristovao Lourenco de; Folgueras, Luiza de Castro [Centro Tecnico Aeroespacial, Sao Jose dos Campos, SP (Brazil). Inst. de Atividades Espaciais

    1995-12-31

    The objective of this work was to study the influence of mixtures of neodymium, niobium and praseodymium oxides, as sintering aids for silicon nitride. Samples were sintered in temperatures between 1700 deg C and 1750 deg C, during 30 minutes. Microstructure, intergranular phases and additives effects on {alpha}-{beta} transformation were evaluated. (author) 10 refs., 2 figs., 8 tabs.

  1. Hydroformylation of 1-Hexene over Rh/Nano-Oxide Catalysts

    Directory of Open Access Journals (Sweden)

    Sari Suvanto

    2013-03-01

    Full Text Available The effect of nanostructured supports on the activity of Rh catalysts was studied by comparing the catalytic performance of nano- and bulk-oxide supported Rh/ZnO, Rh/SiO2 and Rh/TiO2 systems in 1-hexene hydroformylation. The highest activity with 100% total conversion and 96% yield of aldehydes was obtained with the Rh/nano-ZnO catalyst. The Rh/nano-ZnO catalyst was found to be more stable and active than the corresponding rhodium catalyst supported on bulk ZnO. The favorable morphology of Rh/nano-ZnO particles led to an increased metal content and an increased number of weak acid sites compared to the bulk ZnO supported catalysts. Both these factors favored the improved catalytic performance. Improvements of catalytic properties were obtained also with the nano-SiO2 and nano-TiO2 supports in comparison with the bulk supports. All of the catalysts were characterized by scanning electron microscope (SEM, inductively coupled plasma mass spectrometry (ICP-MS, BET, powder X-ray diffraction (PXRD and NH3- temperature-programmed desorption (TPD.

  2. Progress in Nano-Engineered Anodic Aluminum Oxide Membrane Development

    Directory of Open Access Journals (Sweden)

    Gerrard Eddy Jai Poinern

    2011-02-01

    Full Text Available The anodization of aluminum is an electro-chemical process that changes the surface chemistry of the metal, via oxidation, to produce an anodic oxide layer. During this process a self organized, highly ordered array of cylindrical shaped pores can be produced with controllable pore diameters, periodicity and density distribution. This enables anodic aluminum oxide (AAO membranes to be used as templates in a variety of nanotechnology applications without the need for expensive lithographical techniques. This review article is an overview of the current state of research on AAO membranes and the various applications of nanotechnology that use them in the manufacture of nano-materials and devices or incorporate them into specific applications such as biological/chemical sensors, nano-electronic devices, filter membranes and medical scaffolds for tissue engineering.

  3. Synthesis and characterisation of nanostructured neodymium titanium oxides by sol-gel process: Controlling the phase composition, crystal structure and grain size

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, M.R., E-mail: mrm41@cam.ac.uk [Department of Materials Science and Engineering, Sharif University of Technology, Azadi Street, Tehran (Iran, Islamic Republic of); Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Fray, D.J., E-mail: djf25@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)

    2010-08-01

    Nanocrystalline neodymium titanium oxide thin films and powders with different phase compositions with mesoporous structure were produced by a straightforward particulate sol-gel route. The sols were prepared in various Nd:Ti molar ratios and they showed a narrow particle size distribution in the range 20-26 nm. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders contained mixtures of Nd{sub 4}Ti{sub 9}O{sub 24}, Nd{sub 2}Ti{sub 4}O{sub 11}, Nd{sub 3}Ti{sub 4}O{sub 12} for titanium dominant powders (Nd:Ti {<=} 45:60), mixtures of Nd{sub 2}TiO{sub 5} and Nd{sub 2}O{sub 3} for neodymium dominant powders (Nd:Ti {>=} 75:25) and pure Nd{sub 3}Ti{sub 4}O{sub 12} phase for equal molar ratio of Nd:Ti, depending on the annealing temperature and Nd:Ti molar ratio. Moreover, it was found that Nd:Ti molar ratio influences the preferable orientation growth of the neodymium titanium oxide compounds. Transmission electron microscope (TEM) images confirmed that the average crystallite size of the powders annealed at 400 {sup o}C was in the range 1.0-2.8 nm and a gradual increase was occurred up to 6.7 nm by heat treatment at 1000 {sup o}C. The activation energy of crystal growth reduced with a decrease of Nd:Ti molar ratio, calculated in the range 6.90-18.12 kJ mol{sup -1}. Low activation energies indicating that the grain size will not change much with increase in temperature. Field emission scanning electron microscope (FE-SEM) analysis revealed that the deposited thin films had uniform, mesoporous and nanocrystalline structure. Moreover, atomic force microscope (AFM) images presented that the thin films had a columnar like morphology with average grain size in the range 17-30 nm at 600 {sup o}C and 47-60 nm at 800 {sup o}C, depending upon the Nd:Ti molar ratio. Based on Brunauer-Emmett-Taylor (BET) analysis, the synthesized powders showed mesoporous structure containing pores with sphere like shapes. The surface area of the

  4. Effects of nano-copper(II) oxide and nanomagnesium oxide particles on activated sludge.

    Science.gov (United States)

    Liu, Guoqiang; Wang, Jianmin

    2012-07-01

    Effects of nano-copper(II) oxide (nano-CuO) and nanomagnesium oxide (nano-MgO) particles on activated sludge endogenous respiration (aerobic digestion), biochemical oxygen demand (BOD) biodegradation, and nitrification were investigated through respiration rate measurement. For comparison, the effects of Cu(II) and Mg(II) ions on activated sludge were also studied. Results indicated that soluble Cu(II) has half maximum inhibitory concentration (IC50) values of 19, 5.5, 53, and 117 mg Cu/L for endogenous respiration, BOD biodegradation, ammonium oxidation, and nitrite oxidation, respectively. However, nano-CuO only inhibited BOD biodegradation at 240 mg Cu/L or more, and its associated toxicity was primarily caused by soluble Cu(II). In contrast, soluble Mg(II) was not toxic to activated sludge in the experimental concentration range, but nano-MgO inhibited BOD biodegradation and nitrification with IC50 values of 70 and 143 mg Mg/L, respectively. Further study indicated that the toxicity of nano-MgO resulted primarily from increased pH following MgO hydrolysis.

  5. Reactive oxygen species-related activities of nano-iron metal and nano-iron oxides

    Directory of Open Access Journals (Sweden)

    Haohao Wu

    2014-03-01

    Full Text Available Nano-iron metal and nano-iron oxides are among the most widely used engineered and naturally occurring nanostructures, and the increasing incidence of biological exposure to these nanostructures has raised concerns about their biotoxicity. Reactive oxygen species (ROS-induced oxidative stress is one of the most accepted toxic mechanisms and, in the past decades, considerable efforts have been made to investigate the ROS-related activities of iron nanostructures. In this review, we summarize activities of nano-iron metal and nano-iron oxides in ROS-related redox processes, addressing in detail the known homogeneous and heterogeneous redox mechanisms involved in these processes, intrinsic ROS-related properties of iron nanostructures (chemical composition, particle size, and crystalline phase, and ROS-related bio-microenvironmental factors, including physiological pH and buffers, biogenic reducing agents, and other organic substances.

  6. Physical and electrochemical study of cobalt oxide nano- and microparticles

    Energy Technology Data Exchange (ETDEWEB)

    Alburquenque, D. [Dpto. de Química de los Materiales, USACh, Av. L.B.O.‘Higgins 3363, 9170022 Santiago (Chile); Dpto. de Metalurgia, USACh, Av. Ecuador 3469, 9170124, Santiago (Chile); Vargas, E. [Dpto. de Física, USACh and CEDENNA, Av. Ecuador 3493, 9170124 Santiago (Chile); Dpto. de Metalurgia, USACh, Av. Ecuador 3469, 9170124, Santiago (Chile); Denardin, J.C.; Escrig, J. [Dpto. de Física, USACh and CEDENNA, Av. Ecuador 3493, 9170124 Santiago (Chile); Marco, J.F. [Instituto de Química Física “Rocasolano”, CSIC, c/Serrano 119, 28006 Madrid (Spain); Ortiz, J. [Dpto. de Química de los Materiales, USACh, Av. L.B.O.‘Higgins 3363, 9170022 Santiago (Chile); Gautier, J.L., E-mail: juan.gautier@usach.cl [Dpto. de Química de los Materiales, USACh, Av. L.B.O.‘Higgins 3363, 9170022 Santiago (Chile)

    2014-07-01

    Cobalt oxide nanocrystals of size 17–21 nm were synthesized by a simple reaction between cobalt acetate (II) and dodecylamine. On the other hand, micrometric Co{sub 3}O{sub 4} was prepared using the ceramic method. The structural examination of these materials was performed using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM and HRTEM). XRD studies showed that the oxides were pure, well-crystallized, spinel cubic phases with a-cell parameter of 0.8049 nm and 0.8069 nm for the nano and micro-oxide, respectively. The average particle size was 19 nm (nano-oxide) and 1250 μm (micro-oxide). Morphological studies carried out by SEM and TEM analyses have shown the presence of octahedral particles in both cases. Bulk and surface properties investigated by X-ray photoelectron spectroscopy (XPS), point zero charge (pzc), FTIR and cyclic voltammetry indicated that there were no significant differences in the composition on both materials. The magnetic behavior of the samples was determined using a vibrating sample magnetometer. The compounds showed paramagnetic character and no coercivity and remanence in all cases. Galvanostatic measurements of electrodes formed with nanocrystals showed better performance than those built with micrometric particles. - Highlights: • Spinel Co{sub 3}O{sub 4} nanoparticles and microparticles with same structure but with different cell parameters, particle size and surface area were synthesized. • Oxide nanoparticles showed better electrochemical behavior than micrometric ones due to area effect.

  7. Nano silver and nano zinc-oxide in surface waters - exposure estimation for Europe at high spatial and temporal resolution.

    Science.gov (United States)

    Dumont, Egon; Johnson, Andrew C; Keller, Virginie D J; Williams, Richard J

    2015-01-01

    Nano silver and nano zinc-oxide monthly concentrations in surface waters across Europe were modeled at ~6 x 9 km spatial resolution. Nano-particle loadings from households to rivers were simulated considering household connectivity to sewerage, sewage treatment efficiency, the spatial distribution of sewage treatment plants, and their associated populations. These loadings were used to model temporally varying nano-particle concentrations in rivers, lakes and wetlands by considering dilution, downstream transport, water evaporation, water abstraction, and nano-particle sedimentation. Temporal variability in concentrations caused by weather variation was simulated using monthly weather data for a representative 31-year period. Modeled concentrations represent current levels of nano-particle production.Two scenarios were modeled. In the most likely scenario, half the river stretches had long-term average concentrations exceeding 0.002 ng L(-1) nano silver and 1.5 ng L(-1) nano zinc oxide. In 10% of the river stretches, these concentrations exceeded 0.18 ng L(-1) and 150 ng L(-1), respectively. Predicted concentrations were usually highest in July.

  8. Green chemistry synthesis of nano-cuprous oxide.

    Science.gov (United States)

    Ceja-Romero, L R; Ortega-Arroyo, L; Ortega Rueda de León, J M; López-Andrade, X; Narayanan, J; Aguilar-Méndez, M A; Castaño, V M

    2016-04-01

    Green chemistry and a central composite design, to evaluate the effect of reducing agent, temperature and pH of the reaction, were employed to produce controlled cuprous oxide (Cu2O) nanoparticles. Response surface method of the ultraviolet-visible spectroscopy is allowed to determine the most relevant factors for the size distribution of the nanoCu2O. X-ray diffraction reflections correspond to a cubic structure, with sizes from 31.9 to 104.3 nm. High-resolution transmission electron microscopy reveals that the different shapes depend strongly on the conditions of the green synthesis.

  9. 3D Oxidized Graphene Frameworks for Efficient Nano Sieving

    Science.gov (United States)

    Pawar, Pranav Bhagwan; Saxena, Sumit; Badhe, Dhanashree Kamlesh; Chaudhary, Raghvendra Pratap; Shukla, Shobha

    2016-02-01

    The small size of Na+ and Cl- ions provides a bottleneck in desalination and is a challenge in providing alternatives for continuously depleting fresh water resources. Graphene by virtue of its structural properties has the potential to address this issue. Studies have indicated that use of monolayer graphene can be used to filter micro volumes of saline solution. Unfortunately it is extremely difficult, resource intensive and almost impractical with current technology to fabricate operational devices using mono-layered graphene. Nevertheless, graphene based devices still hold the key to solve this problem due to its nano-sieving ability. Here we report synthesis of oxidized graphene frameworks and demonstrate a functional device to desalinate and purify seawater from contaminants including Na+ and Cl- ions, dyes and other microbial pollutants. Micro-channels in these frameworks help in immobilizing larger suspended solids including bacteria, while nano-sieving through graphene enables the removal of dissolved ions (e.g. Cl-). Nano-sieving incorporated with larger frameworks has been used in filtering Na+ and Cl- ions in functional devices.

  10. 3D Oxidized Graphene Frameworks for Efficient Nano Sieving.

    Science.gov (United States)

    Pawar, Pranav Bhagwan; Saxena, Sumit; Badhe, Dhanashree Kamlesh; Chaudhary, Raghvendra Pratap; Shukla, Shobha

    2016-02-19

    The small size of Na(+) and Cl(-) ions provides a bottleneck in desalination and is a challenge in providing alternatives for continuously depleting fresh water resources. Graphene by virtue of its structural properties has the potential to address this issue. Studies have indicated that use of monolayer graphene can be used to filter micro volumes of saline solution. Unfortunately it is extremely difficult, resource intensive and almost impractical with current technology to fabricate operational devices using mono-layered graphene. Nevertheless, graphene based devices still hold the key to solve this problem due to its nano-sieving ability. Here we report synthesis of oxidized graphene frameworks and demonstrate a functional device to desalinate and purify seawater from contaminants including Na(+) and Cl(-) ions, dyes and other microbial pollutants. Micro-channels in these frameworks help in immobilizing larger suspended solids including bacteria, while nano-sieving through graphene enables the removal of dissolved ions (e.g. Cl(-)). Nano-sieving incorporated with larger frameworks has been used in filtering Na(+) and Cl(-) ions in functional devices.

  11. 3D Oxidized Graphene Frameworks for Efficient Nano Sieving

    Science.gov (United States)

    Pawar, Pranav Bhagwan; Saxena, Sumit; Badhe, Dhanashree Kamlesh; Chaudhary, Raghvendra Pratap; Shukla, Shobha

    2016-01-01

    The small size of Na+ and Cl− ions provides a bottleneck in desalination and is a challenge in providing alternatives for continuously depleting fresh water resources. Graphene by virtue of its structural properties has the potential to address this issue. Studies have indicated that use of monolayer graphene can be used to filter micro volumes of saline solution. Unfortunately it is extremely difficult, resource intensive and almost impractical with current technology to fabricate operational devices using mono-layered graphene. Nevertheless, graphene based devices still hold the key to solve this problem due to its nano-sieving ability. Here we report synthesis of oxidized graphene frameworks and demonstrate a functional device to desalinate and purify seawater from contaminants including Na+ and Cl− ions, dyes and other microbial pollutants. Micro-channels in these frameworks help in immobilizing larger suspended solids including bacteria, while nano-sieving through graphene enables the removal of dissolved ions (e.g. Cl−). Nano-sieving incorporated with larger frameworks has been used in filtering Na+ and Cl− ions in functional devices. PMID:26892277

  12. High Performance Nano-Ceria Electrodes for Solid Oxide Cells

    DEFF Research Database (Denmark)

    Graves, Christopher R.; Martinez Aguilera, Lev; Sudireddy, Bhaskar Reddy

    2016-01-01

    In solid oxide electrochemical cells, the conventional Ni-based fuel-electrodes provide high electrocatalytic activity but they are often a major source of long-term performance degradation due to carbon deposition, poisoning of reaction sites, Ni mobility, etc. Doped-ceria is a promising mixed...... ionic-electronic conducting oxide that could solve these issues if it can be integrated into an appropriate electrode structure. Two new approaches to obtain high-performance nanostructured doped-ceria electrodes are highlighted. The first is an infiltration-based architecture with Ce0.8Pr0.2O2-δ...... an unprecedented electrode polarization resistance of ~0.01 Ω cm2 at 650 °C in H2/H2O. These results demonstrate that nano-ceria has the ability to achieve higher performance than Ni-based electrodes and show that the main challenge is obtaining sufficient electronic current collection without adding too much...

  13. Cerium neodymium oxide solid solution synthesis as a potential analogue for substoichiometric AmO2 for radioisotope power systems

    Science.gov (United States)

    Watkinson, E. J.; Ambrosi, R. M.; Williams, H. R.; Sarsfield, M. J.; Stephenson, K.; Weston, D. P.; Marsh, N.; Haidon, C.

    2017-04-01

    The European Space Agency (ESA) is sponsoring a research programme on the development of americium oxides for radioisotope generators and heater units. Cubic AmO2-(x/2) with an O/Am ratio between 1.65 and 1.75 is a potentially suitable compound for pellet sintering. C-type (Ia-3) Ce1-xNdxO2-(x/2) oxides with 0.5 < x < 0.7 could be used as a surrogate for some Ia-3 AmO2-(x/2). A new Ce1-xNdxO2-(x/2) production process has been investigated where a nominally selected x value of 0.6 was targeted: Ce and Nd nitrates and oxalic acid were added drop-wise into a vessel, where they continuously reacted to create oxalate precipitates. The effect of temperature (25 °C, 60 °C) of the reactants (mixed at 250 revolutions per minute) on oxalate particle shape and size were investigated. Oxalates were calcined at 900 °C to produce oxide particles. Oxalate particle properties were characterised as these are expected to influence oxides particle properties and fuel pellet sintering.

  14. Chemoselective Oxidation of Bio-Glycerol with Nano-Sized Metal Catalysts

    DEFF Research Database (Denmark)

    Li, Hu; Kotni, Ramakrishna; Zhang, Qiuyun

    2015-01-01

    to selectively oxidize glycerol and yield products with good selectivity is the use of nano-sized metal particles as heterogeneous catalysts. In this short review, recent developments in chemoselective oxidation of glycerol to specific products over nano-sized metal catalysts are described. Attention is drawn...

  15. Increasing Thermal Conductivity of a Heat Exchanger Using Copper Oxide Nano Fluids & Ethylene Glycol

    Directory of Open Access Journals (Sweden)

    B. Meganathan M.E

    2016-04-01

    Full Text Available A Nano fluid is the evolving concept which is very rarely used in the many core industries. Nano fluids have found a great application in heat exchangers by increasing the thermal conductivity. We have aimed to increasing the heat transfer co-efficient by using copper oxide Nano fluid. The Nano particles are formed by using precipitation method and their fluids are formed by adding surfactants to the base fluid. The comparative study on the Heat exchanger is made by using the CuO Nano Fluid and Hot water. The analysis and the results shows that the overall heat transfer rate increases when subjected to Nano Fluids. The ethylene glycol fluid used along with copper oxide Nano fluid will offer resistance to fouling.

  16. Controlled Growth of Copper Oxide Nano-Wires through Direct Oxidation

    Science.gov (United States)

    Hilman, Joann; Neupane, Ravi; Yost, Andrew J.; Chien, Teyu

    Copper oxides, both Cu2O and CuO, have many applications in solar cells, sensors, and nano-electronics. The properties of the copper oxides are further influenced by the dimension of the materials, especially when made in nanoscale. In particular, the properties of the copper oxide nanowires could be tuned by their structures, lengths, and widths. While several methods have been reported to grow nanowires, direct oxidation is arguably the most economical one. This research examines the effects of oxidization duration and temperature in dry air environment on the development of copper oxide nanowires in order to achieve cost effective controllable growth. Using the direct oxidation method in dry air we have demonstrated growth of CuO nano-wires at temperatures as low as 300 °C and as short as 1hr. Furthermore we have observed that the lengths and diameters of the CuO NWs can be controlled by the duration and temperature of the oxidation process. WY NASA Space Grant Consortium.

  17. Nano-sized Mn oxide/agglomerated silsesquioxane composite as a good catalyst for water oxidation.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Madadkhani, Sepideh

    2016-12-01

    Water splitting to hydrogen and oxygen is an important reaction to store sustainable energies, and water oxidation is identified as the bottleneck for water splitting because it requires the high activation energy to perform. Herein a nano-sized Mn oxide/agglomerated silsesquioxane composite was used to synthesize an efficient catalyst for water oxidation. The composite was synthesized by a straightforward and simple procedure and characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, dynamic light scattering, X-ray diffraction spectrometry, and electrochemical methods. Silsesquioxane causes good dispersion of Mn in the composite. The water-oxidizing activity of this composite was studied in the presence of cerium(IV) ammonium nitrate. The composite at the best calcination temperature (300 °C) shows a turnover frequency 0.3 (mmol O2/mol Mn.s). Regarding the low-cost, environmentally friendly precursors, simple synthesis, and efficiency for water oxidation, the composite is a promising catalyst that can be used in artificial photosynthetic systems for water splitting. We used Agglomerated silsesquioxane as a support for nano-sized Mn oxide to synthesize a good water-oxidizing catalyst.

  18. Linear rheology of water-soluble reversible neodymium (III) coordination polymers

    NARCIS (Netherlands)

    Vermonden, T.; Steenbergen, van M.J.; Besseling, N.A.M.; Marcelis, A.T.M.; Hennink, W.E.; Sudhölter, E.J.R.; Cohen Stuart, M.A.

    2004-01-01

    The rheology of reversible coordination polymer networks in aqueous solution is studied. The polymers are formed by neodymium(III) ions and bifunctional ligands, consisting of two pyridine-2,6-dicarboxylate groups connected at the 4-positions by an ethylene oxide spacer. Neodymium(III) ions can bind

  19. Characterization of nano-scale protective oxide films: application on metal chemical mechanical planarization

    OpenAIRE

    Karagöz, Ayşe; Craciun, V.; Başım, Gül Bahar

    2015-01-01

    This study focuses on the characterization of nano-scale metal oxide films for chemical mechanical planarization (CMP) applications. The protective nature of the self-grown metal oxide layers in the CMP slurry environment enable topographic selectivity required for metallization of interconnects. Tungsten was selected as the model metal film to study the formation and characteristics of the metal oxide nano-layers since tungsten CMP is very well-established in conventional semiconductor manuf...

  20. Catalytic oxidation of gas-phase elemental mercury by nano-Fe2O3

    Institute of Scientific and Technical Information of China (English)

    Fanhai Kong; Jianrong Qiu; Hao Liu; Ran Zhao; Zhihui Ai

    2011-01-01

    Heterogeneous oxidation of gas-phase Hg0 by nano-Fe2O3 was investigated on a fixed bed reactor, and the effects of oxygen concentration, bed temperature, water vapour concentration and particle size have been discussed. The results showed that Hg0 could be oxidized by active oxygen atom on the surface of nano-Fe2O3 as well as lattice oxygen in nano-Fe2O3. Among the factors that affect Hg0 oxidation by nano-Fe2O3, bed temperature plays an important role. More than 40% of total mercury was oxidized at 300℃,however, the test temperature at 400℃ could cause sintering of nano-catalyst, which led to a lower efficiency of Hg0 oxidation. The increase of oxygen concentration could promote mercury oxidation and led to higher Hg0 oxidation efficiency. No obvious mercury oxidation was detected in the pure N2 atmosphere, which indicates that oxygen is required in the gas stream for mercury oxidation. The presence of water vapour showed different effects on mercury oxidation depending on its concentration. The lower content of water vapour could promote mercury oxidation, while the higher content of water vapour inhibits mercury oxidation.

  1. Two-Dimensional Porous Micro/Nano Metal Oxides Templated by Graphene Oxide.

    Science.gov (United States)

    Cao, Hailiang; Zhou, Xufeng; Zheng, Chao; Liu, Zhaoping

    2015-06-10

    Novel two-dimensional (2D) porous metal oxides with micro-/nanoarchitecture have been successfully fabricated using graphene oxide (GO) as a typical sacrificial template. GO as a 2D template ensures that the growth and fusion of metal oxides nanoparticles is restricted in the 2D plane. A series of metal oxides (NiO, Fe2O3, Co3O4, Mn2O3, and NiFe2O4) with similar nanostructure were investigated using this simple method. Some of these special nanostructured materials, such as NiO, when being used as anode for lithium-ion batteries, can exhibit high specific capacity, good rate performance, and cycling stability. Importantly, this strategy of creating a 2D porous micro/nano architecture can be easily extended to controllably synthesize other binary/polynary metal oxides nanostructures for lithium-ion batteries or other applications.

  2. Preparation and Hemocompatibility of Neodymium Incorporated Zinc Oxide Thin Films%钕掺杂ZnO薄膜的制备及抗凝血性能研究

    Institute of Scientific and Technical Information of China (English)

    黄展云; 罗平; 陈弟虎

    2011-01-01

    采用射频磁控溅射方法在硅(100)衬底上制备了不同含量元素钕(Nd)掺杂的氧化锌薄膜.XRD分析表明,所有ZnO薄膜都具有c轴择优取向.随着Nd掺杂量的增加,(002)衍射峰的强度减弱,颗粒的尺寸变小.紫外-可见光谱分析表明,所有薄膜在可见光区的透过率超过85%,随着Nd掺杂量的增加,光学带隙从3.30 eV增加到3.40 eV.用XPS对薄膜的表面化学态进行表征,Nd元素在ZnO薄膜表面以Nd3+离子态存在.用接触角测试薄膜表面的浸润性,并计算其表面能.用血小板粘附实验研究不同含量Nd掺杂ZnO薄膜的血液相容性,其结果表明稀土钕掺杂后血小板的粘附数量和形变都较少,稀土掺杂和疏水性的提高是改善氧化锌薄膜抗凝血性能的主要原因.%Zinc oxide thin films doped with different neodymium (Nd) contents (1at%, 2at% and 3at%) were grown on Si (100) substrates by radio frequency magnetron sputtering. X-ray diffraction (XRD) patterns show that all of the ZnO thin films have highly preferred growth along c-axis direction. The intensity of (002) diffraction peaks weakens and the gain size decreases with the increasing of Nd dopants. The optical transmittance of all the films exceeds 85% in the visible light region, and the optical band gap increases from 3.30 eV to 3.40 eV with the increasing of the Nd dopants. The surface chemical state of ZnO thin films is examined by X-ray photoelectron spectroscope (XPS), confirming that Nd element exists as Nd3+ in the films. Contact angle test is also employed to analyze the effect of Nd dopant on the wettability and surface energy. The platelets adhesion experiment shows that fewer platelets adhere and deform on ZnO and Nd doped ZnO thin films. Nd element and hydrophobility surface are the main factors leading to the better blood compatibility of ZnO thin films.

  3. In Vitro Comparative Skin Irritation Induced by Nano and Non-Nano Zinc Oxide.

    Science.gov (United States)

    Vinardell, Maria Pilar; Llanas, Hector; Marics, Laura; Mitjans, Montserrat

    2017-03-04

    This study was designed to determine whether nano-sized ZnO has the potential to cause acute cutaneous irritation using cultured HaCaT keratinocytes and a human skin equivalent as in vitro models, compared to non-nanomaterials. Commercial nano ZnO with different sizes (50 nm and 100 nm) was characterized by dynamic light scattering (DLS) and microscopy (SEM) in different media. Nano ZnO reduced the cell viability of HaCaT in a dose-dependent and time-dependent manner, in a similar way to macro ZnO. However, the 3D-epidermis model revealed no irritation at 1 mg/mL after 24 h of exposure. In conclusion, nano-sized ZnO does not irritate skin, in a similar manner to non-nano ZnO.

  4. In Vitro Comparative Skin Irritation Induced by Nano and Non-Nano Zinc Oxide

    Directory of Open Access Journals (Sweden)

    Maria Pilar Vinardell

    2017-03-01

    Full Text Available This study was designed to determine whether nano-sized ZnO has the potential to cause acute cutaneous irritation using cultured HaCaT keratinocytes and a human skin equivalent as in vitro models, compared to non-nanomaterials. Commercial nano ZnO with different sizes (50 nm and 100 nm was characterized by dynamic light scattering (DLS and microscopy (SEM in different media. Nano ZnO reduced the cell viability of HaCaT in a dose-dependent and time-dependent manner, in a similar way to macro ZnO. However, the 3D-epidermis model revealed no irritation at 1 mg/mL after 24 h of exposure. In conclusion, nano-sized ZnO does not irritate skin, in a similar manner to non-nano ZnO.

  5. Decorating multiwalled carbon nanotubes with zinc oxide nano-crystallines through hydrothermal growth process

    Institute of Scientific and Technical Information of China (English)

    LI ChenSha; QIAO YingJie; LI YuMing

    2012-01-01

    Multiwalled-carbon nanotubes coated with nano-crystalline zinc oxide (ZnO) was prepared by in situ growth of nano zinc oxide on the surfaces of carbon nanotubes through hydrothermal method.X-ray diffraction,transmission electron microscopy and scanning electron microscopy analysis techniques were used to characterize the samples.It was observed that a layer of nano-crystalline ZnO with the wurtzite hexagonal crystal structure was uniformly coated on the nanotube surfaces with good adhesion,which resulted in the formation of a novel ZnO-nanotube nano composite.In this work,the carbon nanotubes decorated by metal oxide nanoparticles were synthesized by a simple chemical-solution route which is suitable for the large-scale production with low cost.

  6. Metal Ions Removal Using Nano Oxide Pyrolox™ Material

    Science.gov (United States)

    Gładysz-Płaska, A.; Skwarek, E.; Budnyak, T. M.; Kołodyńska, D.

    2017-02-01

    The paper presents the use of Pyrolox™ containing manganese nano oxides used for the removal of Cu(II), Zn(II), Cd(II), and Pb(II) as well as U(VI) ions. Their concentrations were analyzed using the atomic absorption spectrometer SpectrAA 240 FS (Varian) as well as UV-vis method. For this purpose the static kinetic and equilibrium studies were carried out using the batch technique. The effect of solution pH, shaking time, initial metal ion concentrations, sorbent dosage, and temperature was investigated. The equilibrium data were analyzed using the sorption isotherm models proposed by Freundlich, Langmuir-Freundlich, Temkin, and Dubinin-Radushkevich. The kinetic results showed that the pseudo second order kinetic model was found to correlate the experimental data well. The results indicate that adsorption of Cu(II), Zn(II), Cd(II), and Pb(II) as well as U(VI) ions is strongly dependent on pH. The value of pH 4-7 was optimal adsorption. The time to reach the equilibrium was found to be 24 h, and after this time, the sorption percentage reached about 70%. Kinetics of Cu(II), Zn(II), Cd(II), Pb(II), and U(VI) adsorption on the adsorbent can be described by the pseudo second order rate equation. Nitrogen adsorption/desorption, infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) measurements for adsorbent characterization were performed. Characteristic points of the double layer determined for the studied Pyrolox™ sample in 0.001 mol/dm3 NaCl solution are pHPZC = 4 and pHIEP < 2.

  7. Orthogonal adsorption onto nano-graphene oxide using different intermolecular forces for multiplexed delivery.

    Science.gov (United States)

    Wang, Feng; Liu, Biwu; Ip, Alexander C-F; Liu, Juewen

    2013-08-14

    Nano-graphene oxide can adsorb both doxorubicin and zwitterionic dioleoyl-sn-glycero-3-phosphocholine (DOPC) liposomes in an orthogonal and non-competing manner with high capacities based on different surface and intermolecular forces taking place on the heterogeneous surface of the graphene oxide. The system forms stable colloids, allowing co-delivery of both cargos to cancer cells.

  8. Fabrication of polymeric nano-batteries array using anodic aluminum oxide templates.

    Science.gov (United States)

    Zhao, Qiang; Cui, Xiaoli; Chen, Ling; Liu, Ling; Sun, Zhenkun; Jiang, Zhiyu

    2009-02-01

    Rechargeable nano-batteries were fabricated in the array pores of anodic aluminum oxide (AAO) template, combining template method and electrochemical method. The battery consisted of electropolymerized PPy electrode, porous TiO2 separator, and chemically polymerized PAn electrode was fabricated in the array pores of two-step anodizing aluminum oxide (AAO) membrane, based on three-step assembling method. It performs typical electrochemical battery behavior with good charge-discharge ability, and presents a capacity of 25 nAs. AFM results show the hexagonal array of nano-batteries' top side. The nano-battery may be a promising device for the development of Micro-Electro-Mechanical Systems (MEMS), and Nano-Electro-Mechanical Systems (NEMS).

  9. Water soluble nano-scale transient material germanium oxide for zero toxic waste based environmentally benign nano-manufacturing

    Science.gov (United States)

    Almuslem, A. S.; Hanna, A. N.; Yapici, T.; Wehbe, N.; Diallo, E. M.; Kutbee, A. T.; Bahabry, R. R.; Hussain, M. M.

    2017-02-01

    In the recent past, with the advent of transient electronics for mostly implantable and secured electronic applications, the whole field effect transistor structure has been dissolved in a variety of chemicals. Here, we show simple water soluble nano-scale (sub-10 nm) germanium oxide (GeO2) as the dissolvable component to remove the functional structures of metal oxide semiconductor devices and then reuse the expensive germanium substrate again for functional device fabrication. This way, in addition to transiency, we also show an environmentally friendly manufacturing process for a complementary metal oxide semiconductor (CMOS) technology. Every year, trillions of complementary metal oxide semiconductor (CMOS) electronics are manufactured and billions are disposed, which extend the harmful impact to our environment. Therefore, this is a key study to show a pragmatic approach for water soluble high performance electronics for environmentally friendly manufacturing and bioresorbable electronic applications.

  10. Water soluble nano-scale transient material germanium oxide for zero toxic waste based environmentally benign nano-manufacturing

    KAUST Repository

    Almuslem, A. S.

    2017-02-14

    In the recent past, with the advent of transient electronics for mostly implantable and secured electronic applications, the whole field effect transistor structure has been dissolved in a variety of chemicals. Here, we show simple water soluble nano-scale (sub-10 nm) germanium oxide (GeO) as the dissolvable component to remove the functional structures of metal oxide semiconductor devices and then reuse the expensive germanium substrate again for functional device fabrication. This way, in addition to transiency, we also show an environmentally friendly manufacturing process for a complementary metal oxide semiconductor (CMOS) technology. Every year, trillions of complementary metal oxide semiconductor (CMOS) electronics are manufactured and billions are disposed, which extend the harmful impact to our environment. Therefore, this is a key study to show a pragmatic approach for water soluble high performance electronics for environmentally friendly manufacturing and bioresorbable electronic applications.

  11. Direct conversion of corn cob to formic and acetic acids over nano oxide catalysts

    Institute of Scientific and Technical Information of China (English)

    Liyuan; Cheng; Hong; Liu; Yuming; Cui; Nianhua; Xue; Weiping; Ding

    2014-01-01

    Considering energy shortage, large molecules in corn cob and easy separation of solid catalysts, nano oxides are used to transform corn cob into useful chemicals. Because of the microcrystals, nano oxides offer enough accessible sites for cellulose, hemicellulose and monosaccharide from corn cob hydrolysis and oxidant. Chemical conversion of corn cob to organic acids is investigated over nano ceria, alumina, titania and zirconia under various atmospheres. Liquid products are mainly formic and acetic acids. A small amount of other compounds, such as D-xylose,D-glucose, arabinose and xylitol are also detected simultaneously. The yield of organic acids reaches 25%–29% over the nano oxide of ceria,zirconia and alumina with 3 h reaction time under 453 K and 1.2 MPa O2. The unique and fast conversion of corn cob is directly approached over the nano oxides. The results are comparative to those of biofermentation and offer an alternative method in chemically catalytic conversion of corn cob to useful chemicals in a one-pot chemical process.

  12. Aqueous phase deposition of dense tin oxide films with nano-structured surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Yoshitake, E-mail: masuda-y@aist.go.jp; Ohji, Tatsuki; Kato, Kazumi

    2014-06-01

    Dense tin oxide films were successfully fabricated in an aqueous solution. The pH of the solutions was controlled to pH 1.3 by addition of HCl. Precise control of solution condition and crystal growth allowed us to obtain dense tin oxide films. Concave–convex surface of fluorine-doped tin oxide (FTO) substrates was entirely-covered with the continuous films. The films were about 65 nm in thickness and had nano-structured surfaces. Morphology of the films was strikingly different from our previous reported nano-sheet assembled structures. The films were not removed from the substrates by strong water flow or air blow to show strong adhesion strength. The aqueous solution process can be applied to surface coating of various materials such as nano/micro-structured surfaces, particles, fibers, polymers, metals or biomaterials. - Graphical abstract: Dense tin oxide films of 65 nm were successfully fabricated in an aqueous solution. They had nano-structured surfaces. Concave-convex substrates were entirely-covered with the continuous films. - Highlights: • Dense tin oxide films of 65 nm were successfully fabricated in an aqueous solution. • They had nano-structured surfaces. • Concave–convex substrates were entirely-covered with the continuous films.

  13. Weatherability and Leach Resistance of Wood Impregnated with Nano-Zinc Oxide

    Directory of Open Access Journals (Sweden)

    Nami Kartal S

    2010-01-01

    Full Text Available Abstract Southern pine specimens vacuum-treated with nano-zinc oxide (nano-ZnO dispersions were evaluated for leach resistance and UV protection. Virtually, no leaching occurred in any of the nano-ZnO–treated specimens in a laboratory leach test, even at the highest retention of 13 kg/m3. However, specimens treated with high concentrations of nano-ZnO showed 58–65% chemical depletion after 12 months of outdoor exposure. Protection from UV damage after 12 months exposure is visibly obvious on both exposed and unexposed surfaces compared to untreated controls. Graying was markedly diminished, although checking occurred in all specimens. Nano-zinc oxide treatment at a concentration of 2.5% or greater provided substantial resistance to water absorption following 12 months of outdoor exposure compared to untreated and unweathered southern pine. We conclude that nano-zinc oxide can be utilized in new wood preservative formulations to impart resistance to leaching, water absorption and UV damage of wood.

  14. Purification of cerium, neodymium and gadolinium for low background experiments

    Directory of Open Access Journals (Sweden)

    Boiko R.S.

    2014-01-01

    Full Text Available Cerium, neodymium and gadolinium contain double beta active isotopes. The most interesting are 150Nd and 160Gd (promising for 0ν2β search, 136Ce (2β+ candidate with one of the highest Q2β. The main problem of compounds containing lanthanide elements is their high radioactive contamination by uranium, radium, actinium and thorium. The new generation 2β experiments require development of methods for a deep purification of lanthanides from the radioactive elements. A combination of physical and chemical methods was applied to purify cerium, neodymium and gadolinium. Liquid-liquid extraction technique was used to remove traces of Th and U from neodymium, gadolinium and for purification of cerium from Th, U, Ra and K. Co-precipitation and recrystallization methods were utilized for further reduction of the impurities. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe gamma spectrometry. As a result of the purification procedure the radioactive contamination of gadolinium oxide (a similar purification efficiency was reached also with cerium and neodymium oxides was decreased from 0.12 Bq/kg to 0.007 Bq/kg in 228Th, from 0.04 Bq/kg to <0.006 Bq/kg in 226Ra, and from 0.9 Bq/kg to 0.04 Bq/kg in 40K. The purification methods are much less efficient for chemically very similar radioactive elements like actinium, lanthanum and lutetium.

  15. Formulation of nano-zinc oxide into biocomposite beads for dye decolorization

    Science.gov (United States)

    Elkady, M. F.; Hassan, H. Shokry; El-Shazly, A. H.

    2015-03-01

    Zinc oxide nano-powder was prepared using sol-gel technique to be encapsulated onto polymeric blend composed from alginate and polyvinyl alcohol to fabricate novel bio-composite beads of nano-zinc oxide. The XRD patterns of both zinc oxide nano-powder and its polymeric hybrid were crystalline in their nature. The FTIR analysis of the fabricated ZnO polymeric hybrid confirms the binding between zinc oxide and the polymeric matrix. The BET analysis demonstrated that the calculated specific surface area of the formulated ZnO beads that equal to 22.8 m2/g is comparatively less than that of the free ZnO nano-powdered that equivalent to 64.9 m2/g. The thermal stability of ZnO nano-powdered dramatically decreased with its immobilization into the polymeric alginate and PVA matrix. The formulated beads had very strong mechanical strength and they are difficult to be broken up to 1500rpm. Moreover, this hybrid beads are chemically stable at the acidic media. The formulated ZnO hybrid beads verified to be good adsorbent material for C.I basic blue 41 (CB41).

  16. AbstractApplication of Fenton-like process using iron nano oxides for pyrene removal from contaminated soils

    Directory of Open Access Journals (Sweden)

    S. Jorfi

    2014-05-01

    Conclusion: Fenton oxidation using iron nano oxides under defined optimum conditions and neutral pH, can be a suitable alternative to conventional Fenton for remediation of soils contaminated with pyrene.

  17. Large pore volume mesoporous aluminum oxide synthesized via nano-assembly

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A new nano-assembly approach has been proposed for the preparation of macropore volume mesoporous aluminum oxide supports. Secondary nano-assembly and a frame structure mechanism for large pore volume mesoporous supports have been proposed. In a primary nano-assembly supersoluble micelle,aluminum hydroxide nanoparticles were precipitated in situ in surfactants with a volume balance (VB) less than 1,followed by secondary nano-assembly in linear and cylindrical shapes. The secondary nano-assembly of cylindrical aluminum hydroxides was calcined to form nano cylindrical aluminum oxides. For the formation of macropore volume mesoporous supports,we utilized a frame structure mechanism of mesoporous support,in which the exterior surface of the carrier may not be continuous. This macropore volume support has been used for the hydrotreatment of a residual oil catalyst,which possesses the following physical characteristics:pore volume 1.8―2.7 mL·g-1,specific surface area 180―429 m2·g-1,average pore diameter 17―57 nm,average pore diameter more than 10 nm (81%―94%),porosity 87%―93%,and crush strength 7.7―25 N·mm-1.

  18. Phenylboronic acid functionalized reduced graphene oxide based fluorescence nano sensor for glucose sensing

    Energy Technology Data Exchange (ETDEWEB)

    Basiruddin, SK; Swain, Sarat K., E-mail: swainsk2@yahoo.co.in

    2016-01-01

    Reduced graphene has emerged as promising tools for detection based application of biomolecules as it has high surface area with strong fluorescence quenching property. We have used the concept of fluorescent quenching property of reduced graphene oxide to the fluorescent probes which are close vicinity of its surface. In present work, we have synthesized fluorescent based nano-sensor consist of phenylboronic acid functionalized reduced graphene oxide (rGO–PBA) and di-ol modified fluorescent probe for detection of biologically important glucose molecules. This fluorescent graphene based nano-probe has been characterized by high resolution transmission electron microscope (HRTEM), Atomic force microscope (AFM), UV–visible, Photo-luminescence (PL) and Fourier transformed infrared (FT-IR) spectroscopy. Finally, using this PBA functionalized reduced GO based nano-sensor, we were able to detect glucose molecule in the range of 2 mg/mL to 75 mg/mL in aqueous solution of pH 7.4. - Highlights: • Easy and simple synthesis of PBA functionalized reduced GO based nano probe. • PBA functionalized reduced GO graphene based nano-probes are characterized. • PBA functionalized reduced GO nano probe is used to detect glucose molecules. • It is very cost-effective and enzyme-free detection of glucose in solution.

  19. Synthesis of tungsten oxide nano structures by laser pyrolysis

    CSIR Research Space (South Africa)

    Mwakikunga, BW

    2008-01-01

    Full Text Available Since the proposal to synthesise materials by laser assisted pyrolysis in the 1970s, and its practical realisation in 1982, a number of researchers have used this method in obtaining nano-powders from liquid droplets. This study revisits...

  20. Nano

    DEFF Research Database (Denmark)

    Nørgaard, Bent; Engel, Lars Romann

    2007-01-01

    Gennem de sidste par år har et lille ord med et meget stort potentiale gentagende trængt sig på i den offentlige bevidsthed, det er ordet "nano". Nanovidenskab og nanoteknologi er lige nu to af de "hotteste" forskningsområder og betragtes af mange som porten til en helt ny verden af muligheder....... Muligheder, vi endnu ikke kender konsekvenserne af. Center for Kunst og Videnskabs forestilling NANO giver dig chancen for at blive bekendt med verdens mindste byggesten og idégrundlaget for nanoforskningen. Vi har skabt et rum, som på mange måder minder om et laboratorium. Rummet er forsynet med storskærme......, kolber, væsker og nanopartikler. Her vil du f.eks. opleve, hvordan forskere tilfører guld helt nye egenskaber. Forestillingen veksler mellem kemiske arbejdsdemonstrationer, stemningsskabende musik og livlig debat på storskærme mellem eksperter. NANO opfordrer publikum til at tage stilling til forskningen...

  1. Electro-oxidation of methanol at the different carbon materials supported Pt nano-particles

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu.; Zhang, Guojie; Zhou, Yiming; Tang, Yawen; Lu, Tianhong [The Laboratory of Electrochemistry, College of Chemistry and Material Science, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046 (China); Ma, Juan [Institute of Electrochemical Power Sources, Soochow University, Suzhou 215006 (China)

    2010-10-15

    Single-wall carbon nano-tubes (SWNTs), multi-wall carbon nano-tubes (MWNTs) and Vulcan XC-72 carbon (XC-72) are used as supporting carbon materials to prepare Pt/XC-72, Pt/SWNTs and Pt/MWNTs catalysts in tetrahydrofuran/water/ethanol mixture solution. Transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) measurements demonstrate that the type of supporting carbon material affects significantly the morphology and the electronic structure of supported Pt nano-particles (NPs). Electrochemical measurements indicate that the Pt/SWNTs catalyst exhibited the highest current density, the lowest onset oxidation potential and the best stability for methanol electro-oxidation among the three samples, indicating SWNTs are an ideal anode catalyst supporting material for the practical application of direct methanol fuel cells. (author)

  2. Nano-oxide thin films deposited via atomic layer deposition on microchannel plates.

    Science.gov (United States)

    Yan, Baojun; Liu, Shulin; Heng, Yuekun

    2015-01-01

    Microchannel plate (MCP) as a key part is a kind of electron multiplied device applied in many scientific fields. Oxide thin films such as zinc oxide doped with aluminum oxide (ZnO:Al2O3) as conductive layer and pure aluminum oxide (Al2O3) as secondary electron emission (SEE) layer were prepared in the pores of MCP via atomic layer deposition (ALD) which is a method that can precisely control thin film thickness on a substrate with a high aspect ratio structure. In this paper, nano-oxide thin films ZnO:Al2O3 and Al2O3 were prepared onto varied kinds of substrates by ALD technique, and the morphology, element distribution, structure, and surface chemical states of samples were systematically investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoemission spectroscopy (XPS), respectively. Finally, electrical properties of an MCP device as a function of nano-oxide thin film thickness were firstly studied, and the electrical measurement results showed that the average gain of MCP was greater than 2,000 at DC 800 V with nano-oxide thin film thickness approximately 122 nm. During electrical measurement, current jitter was observed, and possible reasons were preliminarily proposed to explain the observed experimental phenomenon.

  3. Effect of morphology and solvent on two-photon absorption of nano zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Kavitha, M.K. [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695547, Kerala (India); Haripadmam, P.C.; Gopinath, Pramod; Krishnan, Bindu [Department of Physics, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695547, Kerala (India); John, Honey, E-mail: honey@iist.ac.in [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695547, Kerala (India)

    2013-05-15

    Highlights: ► ZnO nanospheres and triangular structures synthesis by novel precipitation technique. ► The effect of precursor concentration on the size and shape of nano ZnO. ► Open aperture Z-scan measurements of the ZnO nanoparticle dispersions. ► Nanospheres exhibit higher two photon absorption coefficient than triangular nanostructures. ► Nanospheres dispersed in water exhibit higher two photon absorption coefficient than its dispersion in 2-propanol. - Abstract: In this paper, we report the effect of morphology and solvent on the two-photon absorption of nano zinc oxide. Zinc oxide nanoparticles in two different morphologies like nanospheres and triangular nanostructures are synthesized by novel precipitation technique and their two-photon absorption coefficient is measured using open aperture Z-scan technique. Experimental results show that the zinc oxide nanospheres exhibit higher two-photon absorption coefficient than the zinc oxide triangular nanostructures. The zinc oxide nanospheres dispersed in water exhibit higher two-photon absorption coefficient than that of its dispersion in 2-propanol. The zinc oxide nanospheres dispersed in water shows a decrease in two-photon absorption coefficient with an increase in on-axis irradiance. The result confirms the dependence of shape and solvent on the two-photon absorption of nano zinc oxide.

  4. Sediment and Terrestrial Toxicity and Bioaccumulation of Nano Aluminum Oxide

    Science.gov (United States)

    2011-05-01

    transport • Ecotoxicology •Computational chemistry •Risk and decision analysis Interdisciplinary team of experts in fields of materiel science, geology, soil...as fate, transport in terrestrial and aquatic environments affect organisms? Use in additives/explosives/ propellants Nano Al2O3 particles...dispersed Potential impact on terrestrial/ aquatic organisms Click to edit Master subtitle style BUILDING STRONG® 1. Sources 2. Media and Transport

  5. Mechanical behavior of intragranular, nano-porous electrodeposited zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Raghavan, Rejin, E-mail: r.raghavan@mpie.de [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkstrasse 39, 3602 Thun (Switzerland); Elias, Jamil [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkstrasse 39, 3602 Thun (Switzerland); Erni, Rolf; Parlinska, Magdalena [Empa, Swiss Federal Laboratories for Materials Science and Technology, Electron Microscopy Center, Ueberlandstrasse 129, 8600 Duebendorf (Switzerland); Philippe, Laetitia; Michler, Johann [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkstrasse 39, 3602 Thun (Switzerland)

    2015-03-02

    The mechanical properties and deformation mechanisms of nano-porous ZnO thin films electrodeposited on glass substrates were determined by nanoindentation and in situ scanning electron microscope (SEM) micropillar compression. The intragranular nature of the nanoscale porosity within the individual mono-crystals of the films was probed at nano- and micro-scales for determining their mechanical response. The hardness (3.5 GPa) and reduced elastic modulus (65 GPa) of the compact thin film were found to decrease by increasing the intragranular porosity controlled by the electrochemical deposition potential of ZnO. Focused ion beam (FIB) cross-sections of residual imprints reveal that the decrease in hardness and elastic modulus observed is primarily due to compaction of the nano-porous structure. In situ SEM compression of FIB machined micropillars reveals brittle fracture and near theoretical strengths in the compact film (~ 2 GPa), and a higher flaw tolerant response despite lower failure stress in the most porous film. - Highlights: • Micromechanical behavior of intragranular, nanoporous electrodeposited ZnO thin films • Densification by closure of porosity during indentation • Resistance to fracture by crack deflection and blunting in porous films during microcompression.

  6. Nano-ridge fabrication by local oxidation of silicon edges with silicon nitride as a mask

    NARCIS (Netherlands)

    Haneveld, Jeroen; Berenschot, Erwin; Maury, Pascale; Jansen, Henri

    2006-01-01

    A method to fabricate nano-ridges over a full wafer is presented. The fabrication method uses local oxidation of silicon, with silicon nitride as a mask, and wet anisotropic etching of silicon. The realized structures are 7–20 nm wide, 40–100 nm high and centimeters long. All dimensions are easily a

  7. Nano-ridge fabrication by local oxidation of silicon edges with silicon nitride as a mask

    NARCIS (Netherlands)

    Haneveld, Jeroen; Berenschot, Erwin; Maury, Pascale; Jansen, Henri

    2005-01-01

    A method to fabricate nano-ridges over a full wafer is presented. The fabrication method uses local oxidation of silicon, with silicon nitride as a mask, and wet anisotropic etching of silicon. The realized structures are 7-20 nm wide, 40-100 nm high and centimeters long. All dimensions are easily a

  8. Nano indium oxide as a recyclable catalyst for the synthesis of arylaminotetrazoles

    Indian Academy of Sciences (India)

    Siavash Bahari; Mehdi Ahmadi Sabegh

    2013-01-01

    Nano indium oxide is an effective heterogeneous catalyst for the reaction between aryl cyanamides and sodium azide to synthesize the arylaminotetrazoles in good yields. This method has advantages of high yields, simple methodology, short reaction times and easy work-up. The catalyst can be recovered and reused in good yields.

  9. Self-assembled germanium nano-structures by laser-assisted oxidation

    Institute of Scientific and Technical Information of China (English)

    Huang Wei-Qi; Liu Shi-Rong

    2006-01-01

    The investigation on the oxidation behaviour of Si1-xGex; alloys (x=0.05, 0.15, and 0.25) is carried out. It is found for the first time that on the oxide film a germanium nano-cap with a thickness of 1.8ranging from 5.5 nm to 10 nm are formed by the low-temperature laser-assisted dry oxidation of Si1-xGex substrate. A new scanning method on the decline cross-section of the multiple-layer sample is adopted to measure the layer thickness and the composition. Some new peaks in photoluminescence (PL) spectra are discovered, which could be related to the nano-cap and the nano-particles of germanium. A suitable model and several new calculating formulae with the unrestricted Hartree-Fock-Roothaan (UHFR) method and quantum confinement analysis are proposed to interpret the PL spectra and the nano-structure mechanism in the oxide.

  10. Nano-cluster stability following neutron irradiation in MA957 oxide dispersion strengthened material

    Energy Technology Data Exchange (ETDEWEB)

    Ribis, J., E-mail: joel.ribis@cea.fr [CEA, DEN, DMN, SRMA, F-91191 Gif sur Yvette (France); Lozano-Perez, S. [Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom)

    2014-01-15

    ODS steels are promising materials for Sodium cooled Fast Reactors since their fine distribution of nano-clusters confers excellent mechanical properties. However, the nano-feature stability needs to be assessed under neutron irradiation. Before irradiation, the characterizations show that nano-particles are finely distributed within the ferritic matrix and are identified to have a pyrochlore type structure. After irradiation of the MA957 alloy in the Phenix French reactor at 412 °C up to 50 dpa and 430 °C up to 75 dpa, transmission electron microscopy characterization reveals a very slight density fall but no distinguishable difference in nano-features size before and after irradiation. In addition, after both irradiations, the nano-oxides are still (Y, Ti, O) compounds with orientation relationship with the matrix. A multislice simulation of high resolution images suggests that nano-particles still have a fcc pyrochlore type structure after irradiation. A possible change of lattice parameter seems to be highlighted, possibly due to disordering by cascade effect.

  11. Growth control of carbon nanotubes using by anodic aluminum oxide nano templates.

    Science.gov (United States)

    Park, Yong Seob; Choi, Won Seek; Yi, Junsin; Lee, Jaehyeong

    2014-05-01

    Anodic Aluminum Oxide (AAO) template prepared in acid electrolyte possess regular and highly anisotropic porous structure with pore diameter range from five to several hundred nanometers, and with a density of pores ranging from 10(9) to 10(11) cm(-2). AAO can be used as microfilters and templates for the growth of CNTs and metal or semiconductor nanowires. Varying anodizing conditions such as temperature, electrolyte, applied voltage, anodizing and widening time, one can control the diameter, the length, and the density of pores. In this work, we deposited Al thin film by radio frequency magnetron sputtering method to fabricate AAO nano template and synthesized multi-well carbon nanotubes on a glass substrate by microwave plasma-enhanced chemical vapor deposition (MPECVD). AAO nano-porous templates with various pore sizes and depths were introduced to control the dimension and density of CNT arrays. The AAO nano template was synthesize on glass by two-step anodization technique. The average diameter and interpore distance of AAO nano template are about 65 nm and 82 nm. The pore density and AAO nano template thickness are about 2.1 x 10(10) pores/cm2 and 1 microm, respectively. Aligned CNTs on the AAO nano template were synthesized by MPECVD at 650 degrees C with the Ni catalyst layer. The length and diameter of CNTs were grown 2 microm and 50 nm, respectively.

  12. Nano-cluster stability following neutron irradiation in MA957 oxide dispersion strengthened material

    Science.gov (United States)

    Ribis, J.; Lozano-Perez, S.

    2014-01-01

    ODS steels are promising materials for Sodium cooled Fast Reactors since their fine distribution of nano-clusters confers excellent mechanical properties. However, the nano-feature stability needs to be assessed under neutron irradiation. Before irradiation, the characterizations show that nano-particles are finely distributed within the ferritic matrix and are identified to have a pyrochlore type structure. After irradiation of the MA957 alloy in the Phenix French reactor at 412 °C up to 50 dpa and 430 °C up to 75 dpa, transmission electron microscopy characterization reveals a very slight density fall but no distinguishable difference in nano-features size before and after irradiation. In addition, after both irradiations, the nano-oxides are still (Y, Ti, O) compounds with orientation relationship with the matrix. A multislice simulation of high resolution images suggests that nano-particles still have a fcc pyrochlore type structure after irradiation. A possible change of lattice parameter seems to be highlighted, possibly due to disordering by cascade effect.

  13. Absolute isotopic composition and atomic weight of neodymium using thermal ionization mass spectrometry.

    Science.gov (United States)

    Zhao, Motian; Zhou, Tao; Wang, Jun; Lu, Hai; Fang, Xiang; Guo, Chunhua; Li, Qiuli; Li, Chaofeng

    2005-01-01

    Synthetic mixtures prepared gravimetrically from highly enriched isotopes of neodymium in the form of oxides of well-defined purity were used to calibrate a thermal ionization mass spectrometer. A new error analysis was applied to calculate the final uncertainty of the atomic weight value. Measurements on natural neodymium samples yielded an absolute isotopic composition of 27.153(19) atomic percent (at.%) 142Nd, 12.173(18) at.% 143Nd, 23.798(12) at.% 144Nd, 8.293(7) at.% 145Nd, 17.189(17) at.% 146Nd, 5.756(8) at.% 148Nd, and 5.638(9) at.% 150Nd, and the atomic weight of neodymium as 144.2415(13), with uncertainties given on the basis of 95% confidence limits. No isotopic fractionation was found in terrestrial neodymium materials.

  14. Synthesis of zinc oxide microrods and nano-fibers with dominant exciton emission at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Brito, F., E-mail: fro_brito@yahoo.com.m [Laboratorio de Materiales Optoelectronicos del Centro de Ciencias de Sinaloa, Ave. de las Americas 2771 Col. Villa Universidad 80010, Culiacan, Sinaloa (Mexico); Alejo-Armenta, C. [Laboratorio de Materiales Optoelectronicos del Centro de Ciencias de Sinaloa, Ave. de las Americas 2771 Col. Villa Universidad 80010, Culiacan, Sinaloa (Mexico); Garcia-Hipolito, M. [Departamento de Materiales Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, AP 70-360, Coyoacan 04510, DF (Mexico); Camarillo, E.; Hernandez A, J. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, AP 20-364, Alvaro Obregon 01000, DF (Mexico); Falcony, C. [Departamento de Fisica, CINVESTAV-IPN, AP 14-740, 07000, DF (Mexico); Murrieta S, H. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, AP 20-364, Alvaro Obregon 01000, DF (Mexico)

    2011-05-15

    Employing a simple chemical synthesis method, hexagonal-shaped zinc oxide microrods and zinc oxide nano-fibers were deposited on pyrex-glass and aluminum substrates, respectively. Both kinds of deposits showed zincite crystalline phase with lattice parameters: a=3.2498 A and c=5.2066 A. Microrods showed very uniform wide and large sizes of around 1 and 10 {mu}m, respectively. Both deposits were homogeneous over all substrate surfaces. Microrods and nano-fibers resulted with good optical quality and with preferential crystalline growth in [1 0 1 0]and [0 0 0 1]directions. The principal optical characteristics for both microrods and nano-fibers were: a) room-temperature photo and cathodo-luminescent spectra with strong exciton emission centered around 390 nm and with FWHMs around 125 and 160 meV, respectively, b) poor photo and cathode-luminescent emissions in the visible region of the electromagnetic spectrum, c) energy band gap of 3.32 eV, d) good emission efficiency supported by the not-required high energy densities to obtain strong exciton emission and e) good ZnO stoichiometry endorsed by photoluminescent results. These characteristics make of these microrods and nano-fibers good for potential photonic applications. - Research highlights: {yields} Microrods and nano-fibers resulted with good optical quality and with preferential crystalline growth in [1 0 1 0]and [0 0 0 1]directions. {yields} Microrods and nano-fibers resulted with good emission efficiency supported by the not-required high energy densities to obtain strong exciton emission. {yields} The wet chemical method is appropriated for deposition of microrods and nano-fibers with the desired optical properties for its possible application in photonics.

  15. Selective nano alumina supported vanadium oxide catalysts for oxidative dehydrogenation of ethylbenzene to styrene using CO2 as soft oxidant

    Directory of Open Access Journals (Sweden)

    A.M. Elfadly

    2013-12-01

    Full Text Available Nano alumina-supported V2O5 catalysts with different loadings have been tested for the dehydrogenation of ethylbenzene with CO2 as an oxidant. High surface area nano-alumina was prepared and used as support for V2O5 as the catalyst. The catalysts were synthesized by impregnation techniques followed by calcinations and microwave treatment, denoted as V2O5/γ-Al2O3-C and V2O5/γ-Al2O3-MW, respectively. The V2O5 loading was varied on nano-alumina from 5 to 30 wt%. The support and catalysts were characterized by X-ray diffraction (XRD, Barett–Joyner–Halenda (BJH pore-size distribution, N2-adsorption isotherms, Fourier transform infrared (FT-IR, scanning electron microscopy (SEM, transmission electron microscopy (TEM and temperature programed desorption (TPD-NH3. The characterization results indicated that V2O5 is highly dispersed on alumina up to 30%-V2O5/γ-Al2O3-MW prepared by MW method. The TPD studies indicated that there are significant differences in acid amount and strength for V2O5/γ-Al2O3-C and V2O5/γ-Al2O3-MW-catalysts. The catalytic activity of the prepared catalysts was evaluated in the temperature range 450–600 °C in relation to the physicochemical properties and surface acidity. The results revealed that optimum catalytic activity and selectivity (∼100% toward styrene production were obtained using 10% V2O5/γ-Al2O3-MW catalyst treated with microwave.

  16. Microstructure and Oxidation Behaviors of Nano-particles Strengthened NiCoCrAlY Cladded Coatings on Superalloys

    Institute of Scientific and Technical Information of China (English)

    WANG Hongyu; ZUO Dunwen; CHEN Xinfeng; YU Shouxin; GU Yuanzhi

    2010-01-01

    Nano-particles which can largely improve the microstructure and oxidation resistance of materials are often used as a strengthening component in metal matrix composites. However, few studies were reported on its application in the bond coat of duplex structure thermal barrier coating(TBC). Three kinds of NiCoCrAlY coatings strengthened by different nano-particles with the same addition (1%, mass fraction) were prepared by the laser cladding technique on Ni-based superalloy substrates, aiming to study the effects of the nano-particles on microstructure and oxidation resistance of NiCoCrAlY coatings (the bond coat of the duplex structure thermal barrier coatings). Scanning electron microscope (SEM), X-ray diffractometer(XRD) and thermogravimetry were employed to investigate their morphologies, phases and cyclic oxidation behaviors in atmosphere at 1 050℃, compared with the coating without nano-particles. With the addition of nano-particles, the growth pattern of the grains at the interface changed from epitaxial growth to non-epitaxial growth or part-epitaxial growth; slender dendrites were broken and cellularized; cracks and pores were restrained; and the oxidation weight-gain and the stripping resistance of the oxide scale were improved as well. Among the three kinds of nano-particles, the SiC nano-particles showed the most improvement on microstructure, while the CeO2 nano-particles were insufficient, but its effects on the oxidation resistance are the same as those of the SiC nano-particles. Based on the discussions of the influence mechanism, it is believed that CeO2 nano-particles would show better improvement than SiC nano-particles if the proper amount is added and the proper preparation technique of micro-nanometer composite powders is adopted, with the synergistic action of nanometer effect and reactive element effect.

  17. Catalytic Potential of Nano-Magnesium Oxide on Degradation of Humic Acids From Aquatic Solutions

    OpenAIRE

    Ghorban Asgari; Javad Faradmal; Hassan Zolghadr Nasab; Abdolmotaleb Seidmohammadi

    2014-01-01

    Catalytic ozonation is a new and promising process used to remove the contaminants from drinking water and wastewater. This study aimed to evaluate the catalytic potential of nano-magnesium oxide (nano-MgO) for the removal of humic acids (HA) from water. Mg (NO3)2 solution was used to prepare MgO powder by the calcination method. In a semi-batch reactor, the catalytic ozonation was carried out. The effects of the various operating parameters, including pH, reaction time, T-butyl alcohol (TBA)...

  18. Pyrene Removal from Contaminated Soils by Modified Fenton Oxidation Using Iron Nano Particles

    Directory of Open Access Journals (Sweden)

    Sahand Jorfi

    2013-07-01

    Full Text Available Background:The problems related to conventional Fenton oxidation, including low pH required and production of considerable amounts of sludge have led researchers to investigate chelating agents which might improve the operating range of pH and the use of nano iron particle to reduce the excess sludge. The pyrene removal from contaminated soils by modified Fenton oxidation at neutral pH was defined as the main objective of the current study.Methods:Varying concentrations of H2O2 (0-500 mM and iron nano oxide (0-60 mM, reaction times of 0.5-24 hours and variety of chelating agents including sodium pyrophosphate, sodium citrate, ethylene diamine tetraacetic, fulvic and humic acid were all investigated at pyrene concentration levels of 100 – 500 mg/kg.Results:By applying the following conditions (H2O2 concentration of 300 mM, iron nano oxide of 30 mM, sodium pyrophosphate as chelating agent, pH 3 and reaction time of 6 hours the pyrene removal efficiency at an initial concentration of 100 mg/kg was found to be 99%. As a result, the pyrene concentration was reduced from 100 to 93 mg/kg once the above optimum conditions are met.Conclusions:In this research, the modified Fenton oxidation using iron nano oxide at optimum conditions is introduced as an efficient alternative method in lab scale for chemical remediation or pre-treatment of soils contaminated by pyrene at neutral pH.

  19. Taguchi Optimization for Combustion Synthesis of Aluminum Oxide Nano-particles

    Institute of Scientific and Technical Information of China (English)

    EDRISSI Mohammad; NOROUZBEIGI Reza

    2008-01-01

    Nano-structured aluminum oxide powders were prepared by a combustion synthesis method utilizing serine as a new fuel. The product was sonicated to obtain nano powders. A Taguchi L-4 statistical design of combustion syn- thesis was utilized to optimize the production of γ-alumina powder. The product was characterized by XRD, BET, SEM, EDX and LLS. Nano crystalline γ-alumina with crystal sizes between 4.26 and 5.47 nm and α-Al2O3 powders with crystal sizes 24.51 and 28.62 nm were obtained by the combustion synthesis. The specific surface area was measured by a BET method to be 75.21 m2/g. The average particle size after sonication of product, observed by LLS, was 79.32 nm.

  20. Synthesis and Optical Properties of Neodymium-Doped Lanthanum Fluoride Nano-Laser Materials%氟化镧掺钕纳米激光材料的制备及光学性能

    Institute of Scientific and Technical Information of China (English)

    崔晓霞; 高飞; 候超奇; 郭海涛; 王中跃; 韦玮; 彭波

    2013-01-01

    A new type of neodymium-doped lanthanum fluoride (LaF3 ∶ Nd) nanoparticles are synthesized by hydrothermal method.It exhibits hexagonal structure and a size of about 25 nm.A series of different concentrations of LaF3 ∶ Nd nanoparticles dispersion are prepared by ultrasonic technology.The visible-near-infrared spectra show that the dispersion with the optical path of 5 mm and neodymium ion concentration of 1 × 1020 cm-3 shows high transmittance of 85 % at 1053 nm.The lifetime of the La0.95 Nd0.05 F3 nanoparticles dispersion is 200 μs,compared with that of the powder,it is reduced by 3.8%.These results indicate that the LaF3 ∶Nd nanoparticles dispersion with low fluorescence quenching rate,high ion concentration and high transmittance is a kind of promising material used for high repetition rate,high-power and ultra short pulse liquid laser.%利用水热法制备了新型氟化镧掺钕(LaF3∶Nd)纳米材料,其结构为六方晶型,纳米尺寸在25 nm左右;利用超声波分散技术,制备成了一系列具有不同稀土分散浓度的纳米分散液.其钕离子浓度可达到1×1020 cm-3.可见-近红外透射光谱表明,对于5 mm光程的纳米分散液,其在1053 nm处的透射率大于85%,与掺钕透明陶瓷的透射率相当.荧光寿命测试结果显示,该稀土纳米材料(La0.9sNd0.05F3)在分散液中的寿命值为200 μs,与粉末相比,降低了3.8%,表明这种低荧光猝灭率、高离子浓度、高透射率的纳米分散液将是一种可用于高重复率、高功率、超短脉冲的流体激光工作物质.

  1. Oxidative Stability of Nano-Microstructures containing fish oil

    DEFF Research Database (Denmark)

    García Moreno, Pedro Jesús; Özdemir, N.; Boutrup Stephansen, Karen

    of thermolabile active compounds such as fish oil. Moreover, encapsulates produced present a decreased size, which allows their incorporation into food systems without affecting product sensory qualities. In this work, electrohydrodynamic processing and oxidative stability of NMS containing fish oil were...... solutions and on the morphology of NMS was assayed. Secondly, the oxidative stability of the biopolymer solutions containing emulsified fish oil during storage (14 days at 40 °C) and of NMS loaded with fish oil (e.g. pullulan fibers and dextran and WPC capsules) was determined. Finally, to improve...... the oxidative status of the NMS, pullulan fibers, dextran capsules and WPC capsules were produced by adding neat fish oil instead of emulsified fish oil to the biopolymer solutions. These latter NMS presented a higher oxidative stability, which may be due to a better entrapment of the fish oil into biopolymer...

  2. Nytrox Oxidizers for NanoSat Launch Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Space Propulsion Group, Inc. proposes to conduct systems studies to quantify the performance and cost advantages of Nytrox oxidizers for small launch vehicles. This...

  3. Photoluminescence emission at room temperature in zinc oxide nano-columns

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, L.S.R.; Deus, R.C. [Universidade Estadual Paulista – Unesp, Faculdade de Engenharia de Guaratinguetá, Av. Dr. Ariberto Pereira da Cunha, 333, Bairro Portal das Colinas, CEP 12516-410 Guaratinguetá, SP (Brazil); Foschini, C.R. [Universidade Estadual Paulista – Unesp, Instituto de Química, Laboratório Interdisciplinar em Cerâmica (LIEC), Rua Professor Francisco Degni s/n, CEP 14800-90 Araraquara, SP (Brazil); Moura, F.; Garcia, F. Gonzalez [Universidade Federal de Itajubá – Unifei, Campus Itabira, Rua São Paulo, 377, Bairro Amazonas, CEP 35900-37 Itabira, MG (Brazil); Simões, A.Z., E-mail: alezipo@yahoo.com [Universidade Estadual Paulista – Unesp, Faculdade de Engenharia de Guaratinguetá, Av. Dr. Ariberto Pereira da Cunha, 333, Bairro Portal das Colinas, CEP 12516-410 Guaratinguetá, SP (Brazil)

    2014-02-01

    Highlights: • ZnO nanoparticles were obtained by microwave-hydrothermal method. • X-ray diffraction reveals a hexagonal structure. • Photoluminescence emission evidenced two absorption peaks, at around 480 nm and 590 nm wavelengths. - Abstract: Hydrothermal microwave method (HTMW) was used to synthesize crystalline zinc oxide (ZnO) nano-columns at the temperature of 120 °C with a soaking time of 8 min. ZnO nano-columns were characterized by using X-ray analyses (XRD), infrared spectroscopy (FT-IR), thermogravimetric analyses (TG-DTA), field emission gun and transmission electron microscopy (FEG-SEM and TEM) and photoluminescence properties (PL). XRD results indicated that the ZnO nano-columns are free of any impurity phase and crystallize in the hexagonal structure. Typical FT-IR spectra for ZnO nano-columns presented well defined bands, indicating a substantial short-range order in the system. PL spectra consist of a broad band at 590 nm and narrow band at 480 nm corresponding to a near-band edge emission related to the recombination of excitons and level emission related to structural defects. These results show that the HTMW synthesis route is rapid, cost effective, and could be used as an alternative to obtain ZnO nano-columns in the temperature of 120 °C for 8 min.

  4. Fabrication and mechanical evaluation of hydroxyapatite/oxide nano-composite materials.

    Science.gov (United States)

    Mohamed, Khaled R; Beherei, Hanan H; El Bassyouni, Gehan T; El Mahallawy, Nahed

    2013-10-01

    In the current study, the semiconducting metal oxides such as nano-ZnO and SiO2 powders were prepared via sol-gel technique and conducted on nano-hydroxyapatite (nHA) which was synthesized by chemical precipitation. The properties of fabricated nano-structured composites containing different ratios of HA, ZnO and SiO2 were examined using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. The effect of the variation of ratios between the three components on mechanical, microstructure and in-vitro properties was assessed to explore the possibility of enhancing these properties. The results proved that the mechanical properties exhibited an increment with increasing the ZnO content at the extent of HA. In-vitro study proved the formation and nucleation of apatite onto the surface of the fabricated composites after one week of immersion. It is concluded that HA composites containing SiO2 or SiO2/ZnO content had a suitable mechanical properties and ability to form apatite particles onto the composite surface. Based on bioactivity behavior, Si-HA is more bioactive than pure hydroxyapatite and nano-arrangements will provide an interface for better bone formation. Therefore, these nano-composites will be promising as bone substitutes especially in load bearing sites.

  5. Q-Switching in a Neodymium Laser

    Science.gov (United States)

    Holgado, Warein; Sola, Inigo J.; Jarque, Enrique Conejero; Jarabo, Sebastian; Roso, Luis

    2012-01-01

    We present a laboratory experiment for advanced undergraduate or graduate laser-related classes to study the performance of a neodymium laser. In the experiment, the student has to build the neodymium laser using an open cavity. After that, the cavity losses are modulated with an optical chopper located inside, so the Q-switching regime is…

  6. Nano-structured Platinum-based Catalysts for the Complete Oxidation of Ethylene Glycol and Glycerol

    Science.gov (United States)

    Falase, Akinbayowa

    Direct alcohol fuel cells are a viable alternative to the traditional hydrogen PEM fuel cell. Fuel versatility, integration with existing distribution networks, and increased safety when handling these fuels increases their appeal for portable power applications. In order to maximize their utility, the liquid fuel must be fully oxidized to CO2 so as to harvest the full amount of energy. Methanol and ethanol are widely researched as potential fuels to power these devices, but methanol is a toxic substance, and ethanol has a much lower energy density than other liquids such as gasoline or glucose. Oxidation of complex fuels is difficult to realize, due to difficulty in breaking carbon-carbon bonding and poisoning of the catalysts by oxidative byproducts. In order to achieve the highest efficiency, an anode needs to be engineered in such a way as to maximize activity while minimizing poisoning effects of reaction byproducts. We have engineered an anode that uses platinum-based catalysts that is capable of completely oxidizing ethylene glycol and glycerol in neutral and alkaline media with little evidence of CO poisoning. We have constructed a hybrid anode consisting of a nano-structured PtRu electrocatayst with an NAD-dependent alcohol dehydrogenase for improved oxidation of complex molecules. A nano-structured PtRu catalyst was used to oxidize ethylene glycol and glycerol in neutral media. In situ infrared spectroscopy was used to verify complete oxidation via CO2 generation. There was no evidence of poisoning by CO species. A pH study was performed to determine the effect of pH on oxidative current. The peak currents did not trend at 60 mV/pH unit as would be expected from the Nernst equation, suggesting that adsorption of fuel to the surface of the electrode is not an electron-transfer step. We synthesized nano-structured PtRu, PtSn, and PtRuSn catalysts for oxidation of ethylene glycol and glycerol in alkaline media. The PtRu electrocatalyst the highest oxidative

  7. Comparison the Effect of Zinc Oxide and Magnesium Oxide Nano Particles on Long Term Memory in Adult Male Mice

    Directory of Open Access Journals (Sweden)

    Mahnaz Kesmati

    2016-08-01

    Full Text Available Background Magnesium (Mg and zinc (Zn are two essential elemnts for normal performance of central nervous system. So that the learning and memory are influenced by these ions that antagonized NMDA (N methyl-D-aspartate receptor. Objectives This study was conducted to evaluate the effect of nanoparticles of zinc oxide (ZnO and magnesium oxide (MgO on passive avoidance memory in mice. Methods In this experimental study adult male NMRI mice weighing 25 ± 3g were used. ZnO and MgO nano particles (1, 2.5 and 5 mg/kg, intrapretoneally (i.p. were injected pre-training in model of passive avoidance learning. Memory was evaluated at 1, 3 and 7 days after training. Delay time in coming down from the safe platform in step down apparatus was evaluated as an index of memory. Open field test was used for evaluation the locomotor activity. Results Nano MgO 2.5 and 5 mg/kg increased delay time in coming down from plateform at one day after training (P < 0.05 in dose dependent manner. Nano ZnO 2.5 and 5 mg/kg reduced delay time in coming down from the platform 1, 3 and 7 day after training (P < 0.05 and just 3 days after training (P < 0.05 respectivley. Locomotor activity did not change in presence of MgO and/or ZnO nano particles. Conclusions It seems that various effects of nano ZnO and MgO on long term memeory is related to the different effects of Zn and Mg ions on receptors (such as NMDA involved in memory process. Toxicity and/ or preservation of nanoparticle in body are another possible reasons.

  8. Fabricating nanostructures through a combination of nano-oxidation and wet etching on silicon wafers with different surface conditions.

    Science.gov (United States)

    Huang, Jen-Ching

    2012-01-01

    This study investigates the surface conditions of silicon wafers with native oxide layers (NOL) or hydrogen passivated layers (HPL) and how they influence the processes of nano-oxidation and wet etching. We also explore the combination of nano-oxidation and wet etching processes to produce nanostructures. Experimental results reveal that the surface conditions of silicon wafers have a considerable impact on the results of nano-oxidation when combined with wet etching. The height and width of oxides on NOL samples exceeded the dimensions of oxides on HPL samples, and this difference became increasingly evident with an increase in applied bias voltage. The height of oxidized nanolines on the HPL sample increased after wet etching; however, the width of the lines increased only marginally. After wet etching, the height and width of oxides on the NOL were more than two times greater than those on the HPL. Increasing the applied bias voltage during nano-oxidation on NOL samples increased both the height and width of the oxides. After wet etching however, the increase in bias voltage appeared to have little effect on the height of oxidized nanolines, but the width of oxidized lines increased. This study also discovered that the use of higher applied bias voltages on NOL samples followed by wet etching results in nanostructures with a section profile closely resembling a curved surface. The use of this technique enabled researchers to create molds in the shape of a silicon nanolens array and an elegantly shaped nanoscale complex structures mold.

  9. Effect of Nano-Al₂O₃ on the Toxicity and Oxidative Stress of Copper towards Scenedesmus obliquus.

    Science.gov (United States)

    Li, Xiaomin; Zhou, Suyang; Fan, Wenhong

    2016-06-09

    Nano-Al₂O₃ has been widely used in various industries; unfortunately, it can be released into the aquatic environment. Although nano-Al₂O₃ is believed to be of low toxicity, it can interact with other pollutants in water, such as heavy metals. However, the interactions between nano-Al₂O₃ and heavy metals as well as the effect of nano-Al₂O₃ on the toxicity of the metals have been rarely investigated. The current study investigated copper toxicity in the presence of nano-Al₂O₃ towards Scenedesmus obliquus. Superoxide dismutase activity and concentration of glutathione and malondialdehyde in cells were determined in order to quantify oxidative stress in this study. Results showed that the presence of nano-Al₂O₃ reduced the toxicity of Cu towards S. obliquus. The existence of nano-Al₂O₃ decreased the growth inhibition of S. obliquus. The accumulation of copper and the level of oxidative stress in algae were reduced in the presence of nano-Al₂O₃. Furthermore, lower copper accumulation was the main factor that mitigated copper toxicity with the addition of nano-Al₂O₃. The decreased copper uptake could be attributed to the adsorption of copper onto nanoparticles and the subsequent decrease of available copper in water.

  10. High Performance Nano-Crystalline Oxide Fuel Cell Materials. Defects, Structures, Interfaces, Transport, and Electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, Scott [Northwestern Univ., Evanston, IL (United States); Poeppelmeier, Ken [Northwestern Univ., Evanston, IL (United States); Mason, Tom [Northwestern Univ., Evanston, IL (United States); Marks, Lawrence [Northwestern Univ., Evanston, IL (United States); Voorhees, Peter [Northwestern Univ., Evanston, IL (United States)

    2016-09-07

    This project addresses fundamental materials challenges in solid oxide electrochemical cells, devices that have a broad range of important energy applications. Although nano-scale mixed ionically and electronically conducting (MIEC) materials provide an important opportunity to improve performance and reduce device operating temperature, durability issues threaten to limit their utility and have remained largely unexplored. Our work has focused on both (1) understanding the fundamental processes related to oxygen transport and surface-vapor reactions in nano-scale MIEC materials, and (2) determining and understanding the key factors that control their long-term stability. Furthermore, materials stability has been explored under the “extreme” conditions encountered in many solid oxide cell applications, i.e, very high or very low effective oxygen pressures, and high current density.

  11. Enzymatic biomarkers can portray nanoCuO-induced oxidative and neuronal stress in freshwater shredders.

    Science.gov (United States)

    Pradhan, Arunava; Silva, Carla O; Silva, Carlos; Pascoal, Cláudia; Cássio, Fernanda

    2016-11-01

    Commercial applications of nanometal oxides have increased concern about their release into natural waters and consequent risks to aquatic biota and the processes they drive. In forest streams, the invertebrate shredder Allogamus ligonifer plays a key role in detritus food webs by transferring carbon and energy from plant litter to higher trophic levels. We assessed the response profiles of oxidative and neuronal stress enzymatic biomarkers in A. ligonifer after 96h exposure to nanoCuO at concentration ranges nanoCuO-induced stress, Cu(2+) released from nanoCuO was quantified and the enzymatic responses to Cu(2+) exposure at similar effective concentrations were compared. The highest activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) were observed at concentrations oxidative stress at low concentrations (nanoCuO, thereby contributing to the survival of A. ligonifer. At concentrations between LC10 and LC30, effects of nanoparticulate or released ionic copper on enzyme activities were concentration-dependent, and led to oxidative stress and even to animal death. The activity of acetylcholinesterase (AChE) was strongly inhibited even at concentrations

  12. Evaluating the Microshear Bond Strength and Microleakage of Flowable Composites Containing Zinc Oxide Nano-particles

    OpenAIRE

    Teymoornezhad, Koorosh; Alaghehmand, Homayoun; Daryakenari, Ghazaleh; Khafri, Soraya; Tabari, Mitra

    2016-01-01

    Introduction Preventive resin restorations (PRR) are the conservative choice for the most common carious lesions in children. Thus, new age flowable resin composites with higher filler content are readily used. The aim of this study was to evaluate the microshear bond strength and microleakage of two flowable resin composites containing different percentages of nano zinc oxide (NZnO) particles, which have proven to have antimicrobial properties. Methods This experimental in-vitro study was ca...

  13. Role of TBATB in nano indium oxide catalyzed C-S bond formation

    Science.gov (United States)

    Gogoi, Prasanta; Hazarika, Sukanya; Barman, Pranjit

    2015-09-01

    Nano sized indium oxide is found to be an efficient catalyst for the conversion of thiols to sulfides using Na2CO3 as base and TBATB as reagent in DMSO at 110 °C. Here in situ generation of bromo intermediate by TBATB takes place through indium surface. A variety of aryl sulfides can be synthesized in excellent yields from less reactive chlorides, boronic acids and thiols.

  14. Enhanced Oxidative Stress and Physiological Damage in Daphnia magna by Copper in the Presence of Nano-TiO2

    Directory of Open Access Journals (Sweden)

    W. H. Fan

    2012-01-01

    Full Text Available This study examines the potential hazard of an individual nanomaterial on the Cu biotoxicity to aquatic organisms. Daphnia magna in the absence or presence of nano-TiO2 was exposed to Cu. Maintaining nano-TiO2 at a safe concentration cannot eliminate its potential hazard. The biomarkers superoxide dismutase, catalase, and Na+/K+-ATPase in D. magna were measured. Cu in the presence of nano-TiO2 induced higher levels of oxidative stress and physiological damage because of the sorption of Cu. Nano-TiO2 also caused Na+/K+-ATPase inhibition possibly by impeding the Na+/K+ transfer channel. The correlations among the biomarkers, mortality, and accumulation further showed that the overloading reactive oxygen species generation caused by nano-TiO2 contributed to deeper oxidative stress and physiological regulation, thereby causing greater toxic injury.

  15. Amoxicillin Oxidative Degradation Synthesized by Nano Zero Valent Iron

    Directory of Open Access Journals (Sweden)

    AR Yazdanbakhsh

    2016-03-01

    Full Text Available Introduction: Amoxicillin is one of the most important groups of pharmaceuticals that benefits humans and animals. However, antibiotics excertion in wastewaters and environment have emerged as a serious risk to the biotic environment, and their toxic effects can harm the organisms. Iron-based metallic nanoparticles have received special attention in regard with remediation of groundwater contaminants. In the typical nZVI-based bimetallic particle system, Fe acts as the reducing agent. Thus, the present study aimed to evaluate the synthesis and characteristics of nZVI in regard with degrading AMX. Methods: In this study, nZVI nanoparticles were synthesized using the liquid-phase reduction method by EDTA as a stabilizer material. Structure and properties of nanoparticles were characterized by BET, SEM, XRD and EDX analysis. A multi-variate analysis was applied using a response surface methodology (RSM in order to develop a quadratic model as a functional relationship between AMX removal efficiency and independent variables ( initial pH values, dosage of nZVI, contact time and amoxicillin concentration. The four independent variables of solution pH (2–10, AMX concentration (5-45mg/l, contact time (5-85 min and nanoparticles dose (0.25 – 1.25 g were transformed to the coded values. Results: The study results demonstrated that more than 69 % of AMX was removed by nZVI. The optimal AMX removal conditions using nZVI were found as 1.25 g of nZVI, pH 4, contact time of 80 min and concentration of 30 mg/l. Conclusions: The ability of nZVI in degradation of AMX revealed that these materials can serve as a potential nano material with respect to the environmental remediation.

  16. Fabrication of nano-structures on glass substrate by modified nano-imprint patterning with a plasma-induced surface-oxidized Cr mask

    Science.gov (United States)

    Lee, So Hee; Lee, Su Yeon; Lee, Seong Eui; Lee, Heon; Lee, Hee Chul

    2014-03-01

    In this study, we introduce a process for fabrication of nano-sized structural arrays on glass using modified nano-imprint patterning. A PVC (polyvinyl chloride) stamp was prepared by hot embossing, and a Cr-oxide-pattern etch-mask was used. The etch-mask was formed by oxidizing the surface of exposed Cr region by oxygen plasma treatment at room temperature. The fabrication of the etch-mask was conducted by immersing the locally oxidized Cr pattern in resin remover and Cr-etchant. The residual UV resin and un-oxidized Cr pattern were selectively removed, resulting in the obvious array of Cr-oxide etch-mask-pattern. The array of glass nano-structures was formed by reactive ion etching (RIE) using CF4 and Ar gas discharge. After removing the Cr-oxide mask, the final nano-structure had a height of 40 nm and a diameter of 170 nm, which was slightly less than the diameter of the original master-mold. The plasma treatment gave rise to a rough glass surface with root-mean-square (RMS) roughness of 29.25 nm, while that of bare glass was 0.66 nm. A high optical transmittance due to reduction in reflectance was observed at the plasma-treated rough surface, as well as for the array of nano-structures. The highest measured optical transmittance was 97.2% at a wavelength of 550 nm; an increase of about 7.2% compared to bare glass.

  17. Digital laser printing of metal/metal-oxide nano-composites with tunable electrical properties

    Science.gov (United States)

    Zenou, M.; Sa'ar, A.; Kotler, Z.

    2016-01-01

    We study the electrical properties of aluminum structures printed by the laser forward transfer of molten, femtoliter droplets in air. The resulting printed material is an aluminum/aluminum-oxide nano-composite. By controlling the printing conditions, and thereby the droplet volume, its jetting velocity and duration, it is possible to tune the electrical resistivity to a large extent. The material resistivity depends on the degree of oxidation which takes place during jetting and on the formation of electrical contact points as molten droplets impact the substrate. Evidence for these processes is provided by FIB cross sections of printed structures.

  18. Nano-hardness and elastic modulus of anodic aluminium oxide based Poly (2-hydroxyethylmethacrylate composite membranes

    Directory of Open Access Journals (Sweden)

    Gérrard Eddy Jai Poinern

    2014-07-01

    Full Text Available In this study we determine the elastic and hardness properties of electrochemically engineered porous anodic aluminium oxide (AAO membranes and AAO membranes infiltrated with Poly (2-hydroxyethylmethacrylate to form a unique biologically compatible AAO/polymer composite. The electrochemically-synthesised membranes have a nanometre scale porous oxide structure with a mean pore diameter of 100 nm. The membranes were characterized using field emission scanning electron microscopy before and after polymer infiltration. The polymer treated and untreated membranes were then examined using the nano-indentation technique to measure the hardness and subsequently determine the membrane elasticity.

  19. Synthesis, characterization and properties of nano-sized transition metal oxides

    Science.gov (United States)

    Yin, Ming

    2005-12-01

    Chapter 1. A General introduction to the emerging field of nanomaterials is presented highlighting the category of transition metal oxides. The wide variety of structures, properties, and phenomena of transition metal oxides are stressed. Nano-sized transition metal oxides are presented as systems for fundamental and application research. Examples of individual transition metal oxides are provided. Important developments in the synthesis and characterization of nano-sized transition metal oxides that have contributed to this work are reviewed. A novel synthesis (TDMA) is developed and successfully applied to the synthesis of transition metal oxide nanocrystals. Chapter 2. The synthesis of monodisperse cubic wuestite FexO nanocrystals is presented. The influence of reaction temperature and the molar ratio of surfactant to iron precursor was investigated, in order to further understand the ability to control particle size and monodispersity. In contrast to bulk material, it is also found that the nano-sized ligand-capped wuestite FexO particles were stable at room temperature. The procedure enable the collection of highly monodisperse nanocrystals of variable and uniform diameters as a function of time. Sharp Hancock analysis indicates that the reaction proceeds by a diffusion limited mechanism. Routes to control the size of gamma-Fe2O3 nanocrystals are also presented. gamma-Fe2O3 nanocrystals from 6 nm to 12 nm in diameter with uniform size, shape, consistent crystal structure were prepared. Chapter 3. A simple reaction to prepare monodisperse MnO nanocrystals is presented. MnO nanocrystals was prepared by thermal decomposition of manganese acetate in the presence of oleic acid at high temperature and by following annealing. Particles with different sizes and shapes were obtained by controlling annealing time. The morphology of MnO nanocrystals was studied based on their crystal structure and surface energy. SQUID measurement shows ferromagnetic magnetism at low

  20. Synthesis and characterization of polyethylene oxide based nano composite electrolyte

    Indian Academy of Sciences (India)

    M Malathi; K Tamilarasan

    2014-08-01

    Polyethylene oxide (PEO) – montmorillonite (MMT) composite electrolytes were synthesised by solution casting technique. The salt used for the study is Lithium perchlorate (LiClO4). The morphology and percentage of crystallinity data were obtained through X-ray Diffraction and Differential Scanning Caloriemetry. The ionic conductivity of the polymer electrolytes was studied by impedance spectroscopy. The addition of MMT resulted in an increase in conductivity over the temperature range of 25–60°C. The ionic conductivity of a composite polymer electrolyte containing 1.2 wt% MMT was 1 × 10-5 S cm−1 at 25°C, which is at least one order of magnitude higher than that of the polymer electrolyte (4 × 10-7S cm−1). The increase in ionic conductivity is explained on the basis of crystallinity of the polymer electrolyte.

  1. Phenylboronic acid functionalized reduced graphene oxide based fluorescence nano sensor for glucose sensing.

    Science.gov (United States)

    Basiruddin, S K; Swain, Sarat K

    2016-01-01

    Reduced graphene has emerged as promising tools for detection based application of biomolecules as it has high surface area with strong fluorescence quenching property. We have used the concept of fluorescent quenching property of reduced graphene oxide to the fluorescent probes which are close vicinity of its surface. In present work, we have synthesized fluorescent based nano-sensor consist of phenylboronic acid functionalized reduced graphene oxide (rGO-PBA) and di-ol modified fluorescent probe for detection of biologically important glucose molecules. This fluorescent graphene based nano-probe has been characterized by high resolution transmission electron microscope (HRTEM), Atomic force microscope (AFM), UV-visible, Photo-luminescence (PL) and Fourier transformed infrared (FT-IR) spectroscopy. Finally, using this PBA functionalized reduced GO based nano-sensor, we were able to detect glucose molecule in the range of 2 mg/mL to 75 mg/mL in aqueous solution of pH7.4.

  2. Investigation of the Effect of Yttrium Oxide Nanoparticles Doped with Cerium and Neodymium on Electro-Optics of Liquid Crystal Polymer Composites

    Science.gov (United States)

    Zharkova, G. M.; Osipov, V. V.; Platonov, V. V.; Podkin, A. V.; Strel'tsov, S. A.

    2016-12-01

    Morphology and properties of liquid crystal polymer composites doped with inorganic nanoparticles are described. These composites comprised nematic liquid crystal 5CB, polyvinyl acetate, and nanoparticles of oxides (Y2O3, CeO2:Y2O3, and Nd2O3:Y2O3). Nanopowders were synthesized by the laser method of vaporization of a solid target under CO2-laser or fiber ytterbium laser irradiation. The effect of oxides on the electro-optical properties of the composites and times of response to an electrical pulse is investigated. It is shown that incorporation of CeO2:Y2O3 nanopowder in liquid crystal polymer composites affects the decrease of the control field and the increase of light transmission in an electric field stronger than incorporation of Nd2O3:Y2O3 nanoparticles.

  3. Barium carbonate as an agent to improve the electrical properties of neodymium-barium-copper system at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, J.P. [Post-Graduate Program in Chemical Engineering, Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC, 88040-900 (Brazil); Duarte, G.W. [Post-Graduate Program in Chemical Engineering, Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC, 88040-900 (Brazil); Research Group in Technology and Information, Centro Universitário Barriga Verde (UNIBAVE), Santa Catarina, SC (Brazil); Caldart, C. [Post-Graduate Program in Science and Materials Engineering, Universidade do Extremo Sul Catarinense (UNESC), Criciúma, SC, 88806-000 (Brazil); Kniess, C.T. [Post-Graduate Program in Professional Master in Management, Universidade Nove de Julho, São Paulo, SP (Brazil); Montedo, O.R.K.; Rocha, M.R. [Post-Graduate Program in Science and Materials Engineering, Universidade do Extremo Sul Catarinense (UNESC), Criciúma, SC, 88806-000 (Brazil); Riella, H.G. [Post-Graduate Program in Chemical Engineering, Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC, 88040-900 (Brazil); Fiori, M.A., E-mail: fiori@unochapeco.edu.br [Post-Graduate Program in Environmental Science, Universidade Comunitária da Região de Chapecó (UNOCHAPECÓ), Chapecó, SC, 89809-000 (Brazil); Post-Graduate Program in Technology and Management of the Innovation, Universidade Comunitária da Região de Chapecó (UNOCHAPECÓ), Chapecó, SC, 89809-000 (Brazil)

    2015-11-15

    Specialized ceramics are manufactured under special conditions and contain specific elements. They possess unique electrical and thermal properties and are frequently used by the electronics industry. Ceramics containing neodymium-barium-copper (NBC) exhibit high conductivities at low temperatures. NBC-based ceramics are typically combined with oxides, i.e., NBCo produced from neodymium oxide, barium oxide and copper oxide. This study presents NBC ceramics that were produced with barium carbonate, copper oxide and neodymium oxide (NBCa) as starting materials. These ceramics have good electrical conductivities at room temperature. Their conductivities are temperature dependent and related to the starting amount of barium carbonate (w%). - Highlights: • The new crystalline structure were obtained due presence of the barium carbonate. • The NBCa compound has excellent electrical conductivity at room temperature. • The grain crystalline morphology was modified by presence of the barium carbonate. • New Phases α and β were introduced by carbonate barium in the NBC compound.

  4. Effects of bond coat and top coat (including nano zones) structures on morphology and type of formed transient stage oxides at pre-heat treated nano NiCrAlY/nano ZrO2-8%Y2O3 interface during oxidation

    Institute of Scientific and Technical Information of China (English)

    Mohammadreza Daroonparvar

    2015-01-01

    Bond coat geometry is able to significantly influence thermally grown oxide (TGO) layer formation and growth in thermal barrier coating systems at the onset of oxidation. Moreover, nanostructured yttria stabilized zirconia coating with three model struc-ture (including nano zones) could reduce oxygen partial pressure to the formation pressure of continues alumina oxide scale which was able to protect the substrate from extra oxidation and corrosion. Thus, nano NiCrAlY/nano YSZ and normal NiCrAlY/nano YSZ coatings were prepared by air plasma spray method and then evaluated by high temperature oxidation test at 1000 °C for 160 h. As-sprayed samples were also pre-oxidized at 1000 °C for 48 h and then examined by electrochemical polarization test. The corrosion rate of the pre-oxidized nano NiCrAlY/nano YSZ coating was estimated to be the lowest compared to that of the other samples. It might be related to the formation of continues alumina layer on the nano NiCrAlY at the onset of oxidation. This continuous layer could reduce the penetration of the aggressive solution into the NiCrAlY coating and acted as a protective layer (with the lowest an-odic current density). This layer also lessened TGO growth rate at the stages II and III of the growth.

  5. [Catalytic degradation of PCB77 by microwave-induced nano-particle metal oxides in diatomite].

    Science.gov (United States)

    Huang, Guan-yi; Zhao, Ling; Dong, Yuan-hua

    2009-08-15

    The degradation of PCB77 in diatomite by microwave-induced catalytic oxidation was studied in a sealed vial, including four effects such as microwave (MV) radiating time, addition of different nano-particle metal oxides, concentration and type of acids and dosage of MnO2. The results indicated that PCB77 could be removed significantly by microwave-induced catalytic oxidation. Compared to control reactor (without MV radiation), the removal rate of PCB77 increased by twice after 1 min. In addition, the removal rate of PCB77 under MV radiation was gradually increased with time of radiation and then reached equilibrium after 10 min. The removal rates are about 50% and 20% by addition of H2SO4 and ultrapure water respectively. No significant removal was observed by addition of NaOH and without aqueous media. Moreover, catalytic degradation of PCB77 by microwave-induced nano-particle MnO2 had best removal rate was up to 90% after 1 min, in contrast with addition of nano-particle Fe2O3, CuO and Al2O3. The removal rate raised from 37.0% to 98.5% rapidly with the concentration of H2SO4 ranged from 1 mol/L to 8 mol/L, and H2SO4 mainly played a role of acidification but not oxidation. The addition of 0.01, 0.03 and 0.05 g MnO2 showed the similar result.

  6. Zinc oxide piezoelectric nano-generators for low frequency applications

    Science.gov (United States)

    Nour, E. S.; Nur, O.; Willander, M.

    2017-06-01

    Piezoelectric Zinc Oxide (ZnO) nanogenerators (NGs) have been fabricated for low frequency (work as a triggered sensor for a wireless system using footstep pressure. These studies demonstrate the feasibility of using a ZnO NWs piezoelectric NG as a low-frequency self- powered sensor, with potential applications in wireless sensor networks. After that, we investigated and fabricated a sensor on a PEDOT: PSS plastic substrate using a one-sided growth and double-sided growth technique. For the first growth technique, the fabricated NG has been used as a sensor for an acceleration system; while the fabricated NG by the second technique works as an anisotropic direction sensor. This fabricated configuration showed stability for sensing and can be used in surveillance, security, and auto-Mobil applications. In addition to that, we investigated the fabrication of a sandwiched NG on plastic substrates. Finally, we demonstrated that doping ZnO NWs with extrinsic elements (such as Ag) will lead to the reduction of the piezoelectric effect due to the loss of crystal symmetry. A brief summary into future opportunities and challenges is also presented.

  7. Nano-graphene oxide carboxylation for efficient bioconjugation applications: a quantitative optimization approach

    Energy Technology Data Exchange (ETDEWEB)

    Imani, Rana; Emami, Shahriar Hojjati, E-mail: semami@aut.ac.ir [Amirkabir University of Technology, Department of Biomedical Engineering (Iran, Islamic Republic of); Faghihi, Shahab, E-mail: shahabeddin.faghihi@mail.mcgill.ca, E-mail: sfaghihi@nigeb.ac.ir [National Institute of Genetic Engineering and Biotechnology, Tissue Engineering and Biomaterials Division (Iran, Islamic Republic of)

    2015-02-15

    A method for carboxylation of graphene oxide (GO) with chloroacetic acid that precisely optimizes and controls the efficacy of the process for bioconjugation applications is proposed. Quantification of COOH groups on nano-graphene oxide sheets (NGOS) is performed by novel colorimetric methylene blue (MB) assay. The GO is synthesized and carboxylated by chloroacetic acid treatment under strong basic condition. The size and morphology of the as-prepared NGOS are characterized by scanning electron microscopy, transmission electron microscopy (TEM), and atomic force microscopy (AFM). The effect of acid to base molar ratio on the physical, chemical, and morphological properties of NGOS is analyzed by Fourier-transformed infrared spectrometry (FTIR), UV–Vis spectroscopy, X-ray diffraction (XRD), AFM, and zeta potential. For evaluation of bioconjugation efficacy, the synthesized nano-carriers with different carboxylation ratios are functionalized by octaarginine peptide sequence (R8) as a biomolecule model containing amine groups. The quantification of attached R8 peptides to graphene nano-sheets’ surface is performed with a colorimetric-based assay which includes the application of 2,4,6-Trinitrobenzene sulfonic acid (TNBS). The results show that the thickness and lateral size of nano-sheets are dramatically decreased to 0.8 nm and 50–100 nm after carboxylation process, respectively. X-ray analysis shows the nano-sheets interlaying space is affected by the alteration of chloroacetic acid to base ratio. The MB assay reveals that the COOH groups on the surface of NGOS are maximized at the acid to base ratio of 2 which is confirmed by FTIR, XRD, and zeta potential. The TNBS assay also shows that bioconjugation of the optimized carboxylated NGOS sample with octaarginine peptide is 2.5 times more efficient compared to bare NGOS. The present work provides evidence that treatment of GO by chloroacetic acid under an optimized condition would create a functionalized high

  8. Synthesis of novel cobalt doped zinc oxide/carbon nano composite for the photocatalytic degradation of acid blue 113

    Directory of Open Access Journals (Sweden)

    S. Sunitha

    2015-03-01

    Full Text Available Cobalt doped Zinc Oxide/Carbon nano composite was synthesized by solution combustion method and characterized by X-ray diffractometer, field emission scanning electron microscope and energy dispersive X-ray spectroscopy analysis. This composite shows X-ray diffraction pattern that matched with nano particle of ZnO with wurtzite structure and average grain size was found to be 10.53 nm. . Further the presence of the elements like C, Co, Zn and O was confirmed by energy dispersive X-ray spectroscopy analysis. The effect of Co doping on the photocatalytic activity was investigated by photo degradation of the dye, acid blue 113. This nano composite exhibited better photocatalytic activity when compared to nano ZnO and nano ZnO/C composites.

  9. Stabilization of Pb and Cu in contaminated soils using (nano)oxides - a preliminary study

    Science.gov (United States)

    Komárek, Michael; Michálková, Zuzana; Vaněk, Aleš

    2013-04-01

    Chemical stabilization techniques (the application of various stabilizing amendments, which by chemical means reduces contaminant mobility, bioavailability and bioaccessibility) have shown to be possible less destructive alternatives to conventional remediation options. Most stabilization techniques aim at rendering less available the metal(loid) fractions that can pose significant environmental and/or toxicological risks and protecting the functionality of the soil environment. Nano-particulate oxides (particle size of 1-100 nm) are important scavengers of contaminants in soils and due to their reactive and relatively large specific surface area, engineered oxide nanoparticles are promising materials for the remediation of soils contaminated with inorganic pollutants. However, studies assessing the efficiency of these amendments in contaminated soils are still rather scarce. Therefore, the aim of this work is to evaluate the stabilization efficiency of four (nano)oxides (maghemite, magnetite, gibbsite and amorphous Mn oxide (AMO)) in two soils contaminated with Cu (400 mg/kg; pH 3.6) and Pb (1500 mg/kg; pH 5.5), respectively, using chemical extraction methods (CaCl2, EDTA and the BCR sequential extraction) and direct sampling of soil solution using rhizons. The results suggest that the application of the oxides did not influence the pH of the soils, with the only exception of the AMO, which increased the pH and resulted into the formation of MnCO3 on the oxide surface (data from SEM and XRD). Additionally, the high reactivity of the oxides led to increased DOC concentrations originating from the dissolved soil organic matter, especially in the case of the AMO. The AMO was also the most efficient stabilizing amendment for Cu (most significant decrease in Cu in soil solution, in the exchangeable fraction and CaCl2/EDTA extracts), promoted by the pH increase. Despite their lower particle size, maghemite, magnetite and gibbsite were less efficient; although partial

  10. Thermal treatment of solution-processed nano-sized thin films of molybdenum oxide

    Science.gov (United States)

    Ganchev, M.; Sendova-Vassileva, M.; Popkirov, G.; Vitanov, P.

    2016-10-01

    A solution based deposition method to form nano-sized thin films of molybdenum oxide suitable for photovoltaic device applications is presented. The samples were deposited by spin-coating from molybdenum metal organic precursor solution on soda lime glass substrates. The influence of the process parameters such as spinning regime and concentration of the precursor solutions on the thickness and morphology of the films were investigated. The thermal decomposition of the molybdenum precursor and oxide formation were investigated by differential scanning calorimetry and characteristic patterns showed transitions up to 300oC followed by a zone of stability. Optical spectroscopy measurements in the wavelength range from 300 to 1800 nm presented an increase in transparency when temperature of annealing was raised up to 400oC. Raman scattering analysis revealed the presence of mixed molybdenum oxides. Measurements of the electrical conductivity were performed by the 4-point method.

  11. Supported nano gold as a recyclable catalyst for green, selective and efficient oxidation of alcohol using molecular oxygen

    Directory of Open Access Journals (Sweden)

    Bashir Dar

    2011-09-01

    Full Text Available The myth that gold cannot act as a catalyst has been discarded in view of recent studies, which have demonstrated the high catalytic efficiency of pure nano-gold and supported nano-gold catalysts. In recent years, numerous papers have described the use of supported nano-gold particles for catalysis in view of their action on CO and O2 to form CO2, as well as a variety of other reactions. Special emphasis is placed on the oxidation studies undertaken on model nano-Au systems. In this work a solvent free oxidation of 1-phenyl ethanol was carried out using gold supported on ceria-silica, ceria-titania, ceria- zirconia and ceria-alumina at 160 0C. Almost 88-97% conversion was obtained with >99% selectivity. Temperature screening was done from 70 to 160 0C.Catalysts were prepared by deposition co-precipitation method and deposition was determined by EDEX analysis.

  12. Effect of nano-size nickel particles on wear resistance and high temperature oxidation resistance of ultrafine ceramic coating

    Institute of Scientific and Technical Information of China (English)

    古一; 夏长清; 李佳; 吴安如

    2004-01-01

    In order to improve the wear resistance and high temperature oxidation resistance of titanium and titanium alloy, the high temperature ultra fine ceramic coating containing nano-size nickel particles was prepared by flow coat method on the surface of industrially pure titanium TB1-0. The effects of nano-size nickel particles on the wear resistance and high temperature oxidation resistance of coating substrate system were investigated through oxidation kinetics experiment and wear resistance test. The morphologies of the specimens were examined by means of optical microscopy, scanning electron microscopy and X-ray diffraction. The results show that the high temperature ultra fine ceramic coating has notable protection effect on industrially pure titanium TB1-0 from oxidation. The oxidation and wear resistance properties of the coating can be effectively improved by adding nano-size nickel particles. The decreases from 1. 1 to 0. 6 by adding nano-size nickel particles, and the coating containing 10% (mass fraction) nano-size nickel shows the optimum properties.

  13. Improved Thermally Grown Oxide Scale in Air Plasma Sprayed NiCrAlY/Nano-YSZ Coatings

    Directory of Open Access Journals (Sweden)

    Mohammadreza Daroonparvar

    2013-01-01

    Full Text Available Oxidation has been considered as one of the principal disruptive factors in thermal barrier coating systems during service. So, oxidation behavior of thermal barrier coating (TBC systems with nanostructured and microstructured YSZ coatings was investigated at 1000∘C for 24 h, 48 h, and 120 h. Air plasma sprayed nano-YSZ coating exhibited a trimodal structure. Microstructural characterization also demonstrated an improved thermally grown oxide scale containing lower spinels in nano-TBC system after 120 h of oxidation. This phenomenon is mainly related to the unique structure of the nano-YSZ coating, which acted as a strong barrier for oxygen diffusion into the TBC system at elevated temperatures. Nearly continues but thinner Al2O3 layer formation at the NiCrAlY/nano-YSZ interface was seen, due to lower oxygen infiltration into the system. Under this condition, spinels formation and growth on the Al2O3 oxide scale were diminished in nano-TBC system compared to normal TBC system.

  14. Fabrication of nano-engineered transparent conducting oxides by pulsed laser deposition.

    Science.gov (United States)

    Gondoni, Paolo; Ghidelli, Matteo; Di Fonzo, Fabio; Li Bassi, Andrea; Casari, Carlo S

    2013-02-27

    Nanosecond Pulsed Laser Deposition (PLD) in the presence of a background gas allows the deposition of metal oxides with tunable morphology, structure, density and stoichiometry by a proper control of the plasma plume expansion dynamics. Such versatility can be exploited to produce nanostructured films from compact and dense to nanoporous characterized by a hierarchical assembly of nano-sized clusters. In particular we describe the detailed methodology to fabricate two types of Al-doped ZnO (AZO) films as transparent electrodes in photovoltaic devices: 1) at low O₂ pressure, compact films with electrical conductivity and optical transparency close to the state of the art transparent conducting oxides (TCO) can be deposited at room temperature, to be compatible with thermally sensitive materials such as polymers used in organic photovoltaics (OPVs); 2) highly light scattering hierarchical structures resembling a forest of nano-trees are produced at higher pressures. Such structures show high Haze factor (>80%) and may be exploited to enhance the light trapping capability. The method here described for AZO films can be applied to other metal oxides relevant for technological applications such as TiO₂, Al₂O₃, WO₃ and Ag₄O₄.

  15. Effect of nano-zinc oxide on nitrogenase activity in legumes: an interplay of concentration and exposure time

    Science.gov (United States)

    Kumar, Praveen; Burman, Uday; Santra, P.

    2015-07-01

    Experiments were carried out to study the effect of zinc oxide nanoparticles (nano-ZnO) on nitrogenase activity in legumes. In the first experiment, nodulated roots of cluster bean, moth bean, green gram and cowpea were dipped in Hoagland solution containing 1.5 and 10 μg mL-1 of nano-ZnO for 24 h. Nitrogenase activity in cluster bean, green gram and cowpea roots increased after dipping in solution containing 1.5 μg mL-1 nano-ZnO, but decreased in roots dipped in solution containing 10 μg mL-1 nano-ZnO. However, in moth bean roots, nitrogenase activity decreased after dipping in solution containing either concentration of nano-ZnO. In the second experiment, nodulated roots of green gram were dipped in Hoagland solution containing 1, 4, 6, 8 and 10 μg mL-1 nano-ZnO for 6-30 h before estimating nitrogenase activity. Results showed that an interactive effect of nano-ZnO concentration and exposure time influenced nitrogenase activity. The possible reasons behind this effect have been discussed. A model [ A = 3.44 + 0.46 t - 0.01 t 2 - 0.002 tc 2 ( R 2 = 0.81)] involving linear and power components was developed to simulate the response of nitrogenase activity in green gram roots to the concentration and exposure time of nano-ZnO.

  16. Separating nano graphene oxide from the residual strong-acid filtrate of the modified Hummers method with alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xuebing, E-mail: xuebinghu2010@gmail.com [Key Laboratory of Inorganic Membrane, Jingdezhen Ceramic Institute, Jingdezhen 333001 (China); Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 201800 (China); Yu, Yun, E-mail: yunyush@mail.sic.ac.cn [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 201800 (China); Wang, Yongqing; Zhou, Jianer [Key Laboratory of Inorganic Membrane, Jingdezhen Ceramic Institute, Jingdezhen 333001 (China); Song, Lixin [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 201800 (China)

    2015-02-28

    Graphical abstract: By adding an alkaline (NaOH or KOH) solution, the unprecipitated nano graphene oxide undergoes fast aggregation from the residual strong-acid filtrate of the modified Hummers method and forms the stable floccules when the pH value of the filtrate is about 1.7. The acid–base interaction with the surface functional groups of the carbon layers plays a role in the aggregation of the unprecipitated nano graphene oxide. - Highlights: • The novel and high-efficient method for separating graphene oxide was showed. • Graphene oxide undergoes aggregation and forms the floccules when pH value is ∼1.7. • The acid–base interaction plays a role in the aggregation of graphene oxide. - Abstract: In the modified Hummers method for preparing graphene oxide, the yellow slurry can be obtained. After filtering through a quantitative filter paper, the strong-acid filtrate containing the unprecipitated nano graphene oxide was gained. The corresponding filtrate was added gradually with an alkaline (NaOH or KOH) solution at room temperature. The unprecipitated nano graphene oxide could undergo fast aggregation when the pH value of the filtrate was about 1.7 and formed the stable floccules. X-ray diffraction analysis shows the dominant peak of the floccules is about 11°, which accords to the peak of graphene oxide. Spectra of X-ray photoelectron spectroscopy confirm the presence in the floccules of an abundance of oxygen functional groups and the purified graphene oxide floccules can be obtained. Atomic force microscopy measurement shows the graphene oxide floccules consists of sheet-like objects, mostly containing only a few layers (about 5 layers). Zeta potential analysis demonstrates the surface charge of the graphene oxide is pH-sensitive and its isoelectric point is ∼1.7. The flocculation mechanism of graphene oxide ascribes to the acid–base interaction with the surface functional groups of the carbon layers.

  17. Synthesis, Characterization of Nano Tin Oxide via Co-precipitation Method

    Directory of Open Access Journals (Sweden)

    K. Sujatha

    2016-09-01

    Full Text Available Pure SnO2 nano powders were synthesized by co-precipitation method. The structure, surface, optical, and functional groups were analyzed by X-ray diffraction, FESEM, UV-Vis spectroscopy, FTIR and fluorescence spectra, respectively. The results were compared with pure tin oxide nanoparticle. X-ray analysis shows that the obtained power has tetragonal rutile structure with average crystallite size of 34 nm. Band gap is observed from UV-Vis spectroscopy. Fluorescence spectrum of pure sample detected a strong emission peaks at 634nm due to surface defect and oxygen vacancies in SnO2 nanoparticles.

  18. Effect of Nano-Particle of Magnesium Oxide on Ketamine-Induced Anesthesia in Rabbit

    OpenAIRE

    N. Kavosi; Najafzadeh, H.; M. Bavari; A. Esmailirad

    2012-01-01

    Some studies show magnesium has analgesic effect in some pain models but this evaluation was not carried on nano-Magnesium Oxide (MgO). Thus, present study was designed to evaluation effect of Mgo nanoparticles and conventional MgO on ketamine-induced anesthesia in rabbits. At this study, 20 adult rabbits were used in 4 groups. Ketamine was intrapritonealy injected in all groups and xylazine, MgO nanoparticle and MgO suspension was administrated 15 min before ketamine injection in 3 last grou...

  19. Mechanosynthesis, crystal structure and magnetic characterization of neodymium orthoferrite

    Energy Technology Data Exchange (ETDEWEB)

    Serna, Pedro Vera; Campos, Cecilio Garcia [Division de Ingenierias, Universidad Politecnica de Tecamac (UPTECAMAC), Tecamac de Felipe Villanueva, Estado de Mexico (Mexico); De Jesus, Felix Sanchez; Miro, Ana Maria Bolarin [Area Academica de Ciencias de la Tierra y Materiales, Universidad Autonoma del Estado de Hidalgo (UAEH), Mineral de la Reforma, Hidalgo (Mexico); Loran, Jose Antonio Juanico [Division de Ingenieria Industrial Nanotecnologia, Universidad Politecnica del Valle de Mexico (UPVM), Tultitlan, Estado de Mexico (Mexico); Longwell, Jeffrey, E-mail: pedrovera.upt@gmail.com [Department of Languages and Linguistics, New Mexico State University (NMSU), Las Cruces, NM (United States)

    2016-03-15

    Neodymium orthoferrite NdFeO{sub 3} was obtained at room temperature by mechanosynthesis with a stoichiometric ratio of Nd2O{sub 3} and Fe{sub 2}O{sub 3} powders, whereas the traditional synthesis requires a temperature of approximately 1000 °C. The crystal structure was analyzed by X-ray diffraction analysis using Cu radiation and a LynxEye XE detector, whose strong fluorescence filtering enabled a high signal intensity. The analysis indicated that the obtained crystallites were nano-sized. The particle morphology was observed by scanning electron microscopy, and the magnetic saturation was tested by vibrating sample magnetometry. The synthesis of NdFeO{sub 3} was detected after a few hours of milling, indicating that the milling imparted mechanical energy to the system. (author)

  20. Uniting Superhydrophobic, Superoleophobic and Lubricant Infused Slippery Behavior on Copper Oxide Nano-structured Substrates

    Science.gov (United States)

    Ujjain, Sanjeev Kumar; Roy, Pritam Kumar; Kumar, Sumana; Singha, Subhash; Khare, Krishnacharya

    2016-01-01

    Alloys, specifically steel, are considered as the workhorse of our society and are inimitable engineering materials in the field of infrastructure, industry and possesses significant applications in our daily life. However, creating a robust synthetic metallic surface that repels various liquids has remained extremely challenging. The wettability of a solid surface is known to be governed by its geometric nano-/micro structure and the chemical composition. Here, we are demonstrating a facile and economical way to generate copper oxide micro-nano structures with spherical (0D), needle (1D) and hierarchical cauliflower (3D) morphologies on galvanized steel substrates using a simple chemical bath deposition method. These nano/micro textured steel surfaces, on subsequent coating of a low surface energy material display excellent superhydrophobic, superoleophobic and slippery behavior. Polydimethylsiloxane coated textured surfaces illustrate superhydrophobicity with water contact angle about 160°(2) and critical sliding angle ~2°. When functionalized with low-surface energy perfluoroalkylsilane, these surfaces display high repellency for low surface tension oils as well as hydrocarbons. Among them, the hierarchical cauliflower morphology exhibits re-entrant structure thereby showing the best superoleophobicity with contact angle 149° for dodecane. Once infused with a lubricant like silicone oil, they show excellent slippery behavior with low contact angle hysteresis (~ 2°) for water drops. PMID:27752098

  1. Catalytic Potential of Nano-Magnesium Oxide on Degradation of Humic Acids From Aquatic Solutions

    Directory of Open Access Journals (Sweden)

    Ghorban Asgari

    2014-12-01

    Full Text Available Catalytic ozonation is a new and promising process used to remove the contaminants from drinking water and wastewater. This study aimed to evaluate the catalytic potential of nano-magnesium oxide (nano-MgO for the removal of humic acids (HA from water. Mg (NO32 solution was used to prepare MgO powder by the calcination method. In a semi-batch reactor, the catalytic ozonation was carried out. The effects of the various operating parameters, including pH, reaction time, T-butyl alcohol (TBA and phosphate on HA degradation were evaluated. Experimental results indicated that degradation of HA was increased as the pH solution and reaction time were increased. Maximum HA degradation was obtained at pH = 10 and the reaction time of 10 minutes in the catalytic process. The calculated catalytic potential of nano-MgO on ozonation of HA was 60%. Moreover, catalytic ozonation process was not affected by TBA and the main reaction on HA degradation HA have effect take place on MgO surface. According to the results of this study, the developed MgO catalyst is the active and proficient catalyst in HA degradation using the catalytic ozonation process.

  2. Uniting Superhydrophobic, Superoleophobic and Lubricant Infused Slippery Behavior on Copper Oxide Nano-structured Substrates

    Science.gov (United States)

    Ujjain, Sanjeev Kumar; Roy, Pritam Kumar; Kumar, Sumana; Singha, Subhash; Khare, Krishnacharya

    2016-10-01

    Alloys, specifically steel, are considered as the workhorse of our society and are inimitable engineering materials in the field of infrastructure, industry and possesses significant applications in our daily life. However, creating a robust synthetic metallic surface that repels various liquids has remained extremely challenging. The wettability of a solid surface is known to be governed by its geometric nano-/micro structure and the chemical composition. Here, we are demonstrating a facile and economical way to generate copper oxide micro-nano structures with spherical (0D), needle (1D) and hierarchical cauliflower (3D) morphologies on galvanized steel substrates using a simple chemical bath deposition method. These nano/micro textured steel surfaces, on subsequent coating of a low surface energy material display excellent superhydrophobic, superoleophobic and slippery behavior. Polydimethylsiloxane coated textured surfaces illustrate superhydrophobicity with water contact angle about 160°(2) and critical sliding angle ~2°. When functionalized with low-surface energy perfluoroalkylsilane, these surfaces display high repellency for low surface tension oils as well as hydrocarbons. Among them, the hierarchical cauliflower morphology exhibits re-entrant structure thereby showing the best superoleophobicity with contact angle 149° for dodecane. Once infused with a lubricant like silicone oil, they show excellent slippery behavior with low contact angle hysteresis (~ 2°) for water drops.

  3. High temperature oxidation of WC-CrN Nano-multilayered film at 700 and 800 degrees C.

    Science.gov (United States)

    Lee, Dong-Bok

    2009-12-01

    Nano-multilayered WC-CrN films were deposited onto steel substrates by an arc ion plating method. The oxidation characteristics of the films were studied at 700 and 800 degrees C for up to 60 h in air. In each case, during oxidation, carbon and nitrogen escaped from the film into the air, while oxygen from the air diffused into the film. Substrate elements diffused outwards towards the oxide surface. The high-temperature oxidation resistance was not satisfactory, mainly due to the formation of a non-protective, volatile W-oxide scale, and the escape of carbon and nitrogen from the film. The scale formed was prone to cracking and spallation. The oxidation resulted in the destruction of the original nano-multilayers.

  4. Study on F-F Transitions of Powdered Neodymium Compounds by Photoacoustic Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    杨跃涛; 苏庆德; 赵贵文; 张淑仪

    2002-01-01

    Photoacoustic (PA) spectra of powdered neodymium oxide (Nd2O3 (A type)), neodymium hydrated chloride (NdCl3*6H2O) and neodymium fluoride (NdF3) were reported. PA band shifts as compared to their positions in aqueous Nd3+ are used to calculate the nephelauxetic parameters of the compounds. The variation of these parameters and correlation with the nature of metal-ligand bonding were discussed. A novel method is introduced to determine the relative values of oscillator strengths and Judd-Ofelt parameters of powdered samples using PA spectroscopy. It is found that a linear correlation exists between relative values of τ2 and oscillator strengths of hypersensitive transitions of the title compounds. It is hopetul that the new method of PA technique may serve for the Judd-Ofelt quantitative analysis of powdered rare earth compounds.

  5. Kinetics of solid-gas reactions characterized by scanning AC nano-calorimetry with application to Zr oxidation

    Science.gov (United States)

    Xiao, Kechao; Lee, Dongwoo; Vlassak, Joost J.

    2014-10-01

    Scanning AC nano-calorimetry is a recently developed experimental technique capable of measuring the heat capacity of thin-film samples of a material over a wide range of temperatures and heating rates. Here, we describe how this technique can be used to study solid-gas phase reactions by measuring the change in heat capacity of a sample during reaction. We apply this approach to evaluate the oxidation kinetics of thin-film samples of zirconium in air. The results confirm parabolic oxidation kinetics with an activation energy of 0.59 ± 0.03 eV. The nano-calorimetry measurements were performed using a device that contains an array of micromachined nano-calorimeter sensors in an architecture designed for combinatorial studies. We demonstrate that the oxidation kinetics can be quantified using a single sample, thus enabling high-throughput mapping of the composition-dependence of the reaction rate.

  6. Effect of magnetic and nonmagnetic nano metal oxides doping on the critical temperature of a YBCO superconductor

    Science.gov (United States)

    Salama, A. H.; El-Hofy, M.; Rammah, Y. S.; Elkhatib, M.

    2015-12-01

    Bulk superconductor samples of YBa2Cu3O7-δ (YBCO) doped with nano metal oxides of Mn3O4, Co3O4, Cr2O3, CuO and SnO2 respectively with 0.2 wt% are synthesized by a solid-state reaction route. The structural characterization of all samples has been carried out by x-ray diffraction (XRD) and scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The XRD patterns indicate that the magnetic doping of nano metal oxides ≤ft({{{Mn}}}{{3}}{{{O}}}{{4}}, {{{Co}}}{{3}}{{{O}}}{{4}}, {{{Cr}}}{{2}}{{{O}}}{{3}}\\right) gives a high value of orthorhombicity of the YBCO samples which is the result of high oxygen content, and consequently could give better superconducting properties contrary to the non magnetic nano oxides (CuO, SnO2). The critical temperature (Tc) of the studied samples was found to improve by nano magnetic doping and lower with nano nonmagnetic doping. The superconducting transition temperature Tc determined from electrical resistivity measurements was found to increase for Mn3O4 (5.27 μB) doping and decrease for other metal oxides doping.

  7. Graphene supported nano particles of Pt-Ni for CO oxidation

    Science.gov (United States)

    Zhang, Cheng; Lv, Wei; Yang, Quanhong; Liu, Yuan

    2012-08-01

    In this study, a series of graphene supported Pt, Ni and Pt-Ni nano particles were successfully synthesized by a simple impregnation method. The resultant composites were characterized using SEM, XRD, HRTEM, XPS and TPR techniques and their catalytic performance for the oxidation of carbon monoxide was tested. It was shown that in the prepared metal/graphene composite, metal particles were highly dispersed on the graphene sheets (GS) with an average particle size of 1-3 nm. The results of catalytic performance tests indicate that the activity decreases in the order of Pt-Ni/GS, Pt/GS and Ni/GS. In the sample of Pt-Ni/GS, Pt-Ni alloy was formed, which contributed to the high activity of Pt-Ni/GS for CO oxidation.

  8. Photocatalytic self-cleaning properties of cellulosic fibers modified by nano-sized zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Moafi, Hadi Fallah; Shojaie, Abdollah Fallah, E-mail: a.f.shojaie@guilan.ac.ir; Zanjanchi, Mohammad Ali

    2011-03-31

    Nano-sized zinc oxide was synthesized and deposited onto cellulosic fibers using the sol-gel process at ambient temperature. The prepared materials were characterized using several techniques including scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogravimetric analysis. X-ray diffraction studies of the ZnO-coated fiber indicate formation of the hexagonal crystal phase which was satisfactory crystallized on the fiber surface. The electron micrographs show formation of zinc oxide nanoparticles within 10-15 nm in size which have been homogeneously dispersed on the fiber surface. The prepared materials show significant photocatalytic self-cleaning activity, which was monitored by diffuse reflectance spectroscopy. The photoactivity was studied upon measuring the photodegradation of methylene blue and eosin yellowish under UV-Vis irradiation. The photocatalytic activity of the treated fabrics was fully maintained performing several cycles of photodegradation.

  9. Investigation of ionic conductivity of lanthanum cerium oxide nano crystalline powder synthesized by co precipitation method

    Science.gov (United States)

    Tinwala, Hozefa; Shah, Patij; Siddhapara, Kirit; Shah, Dimple; Menghani, Jyoti

    2016-10-01

    Lanthanum (La) doped Ceria (CeO2) electrolyte has attracted considerable interest, as a candidate material for solid oxide fuel cells (SOFCs). The ionic conductivity of La doped CeO2 system (La2Ce2O7) nano-particles synthesized by the co-precipitation method has been investigated. The cubic fluorite structure was observed from the structural analysis of the material. Morphology of the sintered pellets are observed by scanning electron microscope (SEM), respectively. From the results of impedance spectroscopy from temperature range of room temperature to 400 °C, the oxide ion conductivity due to proton charge carrier was observed. Thermogravimetric analysis (TGA) was performed on the material to check stability of phase at high temperature.

  10. Facile cathodic electrosynthesis and characterization of iron oxide nano-particles

    Institute of Scientific and Technical Information of China (English)

    Taher Yousefi; Reza Davarkhah; Ahmad Nozad Golikand; Mohammad Hossein Mashhadizadeh; Ahmad Abhari

    2013-01-01

    Fe2O3 nano-particles have been synthesized by simple cathodic electrodeposition from the low-temperature nitrate bath. The morphology and crystal structure of the obtained oxide powder were analyzed by means of scanning and transmission microscopy (SEM and TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Thermal behavior and phase transformation during the heat treatment of as-deposited sample were investigated by differential scanning calorimetry (DSC) and thermogramimetric analysis (TGA). The results showed that the deposited Fe2O3 was composed of the nanoparticles with grain size of approximately 10-60 nm. A serious problem during cathodic electrodeposition of iron oxide was splashing of deposit into electrolyte due to its low adhesion. This problem was tackled by reducing the bath temperature and dielectric constant of solvent.

  11. Honeycomb nano cerium oxide fabricated by vacuum drying process with sodium alginate

    Science.gov (United States)

    Zhao, Guozheng; Li, Changbo; Zhang, Honglin

    2017-06-01

    Nano cerium oxide (CeO2) with honeycomb structure were synthesized simply and rapidly by vacuum drying method with sodium alginate as the biological template agent, Ce(NO3)3·6H2O as cerium source. The composition, aperture size, specific surface area and morphology of the prepared samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), N2 adsorption-desorption and scanning electron microscopy (SEM). Simultaneously, the effects on the morphology of the samples, which were caused by the drying method and the concentration of sodium alginate, were investigated. The results indicate that the prepared samples were nano CeO2 with high crystallinity and uniform dispersion, most of which had mesoporous, macroporous and honeycomb structure. The specific surface area of CeO2 is 210.0 m2/g, and the average aperture is 12.77 nm. The prepared samples can act as catalyst in the catalytic wet oxidation process for the treatment of high concentration organic wastewater, and the COD removal rate could exceed 90%.

  12. Oxidation-Based Continuous Laser Writing in Vertical Nano-Crystalline Graphite Thin Films

    Science.gov (United States)

    Loisel, Loïc; Florea, Ileana; Cojocaru, Costel-Sorin; Tay, Beng Kang; Lebental, Bérengère

    2016-05-01

    Nano and femtosecond laser writing are becoming very popular techniques for patterning carbon-based materials, as they are single-step processes enabling the drawing of complex shapes without photoresist. However, pulsed laser writing requires costly laser sources and is known to cause damages to the surrounding material. By comparison, continuous-wave lasers are cheap, stable and provide energy at a more moderate rate. Here, we show that a continuous-wave laser may be used to pattern vertical nano-crystalline graphite thin films with very few macroscale defects. Moreover, a spatially resolved study of the impact of the annealing to the crystalline structure and to the oxygen ingress in the film is provided: amorphization, matter removal and high oxygen content at the center of the beam; sp2 clustering and low oxygen content at its periphery. These data strongly suggest that amorphization and matter removal are controlled by carbon oxidation. The simultaneous occurrence of oxidation and amorphization results in a unique evolution of the Raman spectra as a function of annealing time, with a decrease of the I(D)/I(G) values but an upshift of the G peak frequency.

  13. Prospects of zinc nano oxide application in the treatment of purulent wounds

    Directory of Open Access Journals (Sweden)

    Popadyuk O.Ya.

    2015-03-01

    Full Text Available Surgical infection is a difficult problem in modern medical practice. Prevalence of surgical infection, new strains of microorganisms and their resistance to antibiotics, poor outcomes of wound treatment, lack of sensitivity of microorganisms to commonly used antiseptics necessitate the search for the new methods and means of treatment in wound surgery. This article provides an overview of domestic and foreign literature on the possibility of solving the problem of effective local treatment of purulent wounds through the study and implementation of nanotechnology in modern medicine. Researchers around the world are beginning to use nanoparticles and developments of nanotechnology in various fields of science and medicine to synthesize new drugs and vaccines, including zinc nano oxide usage as a highly effective local antiseptic that is non-toxic to the cells of the human body at very low, concentrations but with sufficient antibacterial action. Small sizes and large surface area relatively to volume increases efficiency of interaction of nanoparticles with germs and makes it probable a wide range of antimicrobial activity. Nanoparticles on metals base due to their biological and physical-chemical properties are perspective antibacterial agents and may be used to solve many problems in nanomedicine and surgery in particular. Study and application of zinc nano oxide in preparations of multidirectional local action will ensure high effective defense against pathogenic microorganisms in the wound.

  14. Subcutaneous Connective Tissue Reaction to a New Nano Zinc-Oxide Eugenol Sealer in Rat Model

    Science.gov (United States)

    Omidi, Salma; Javidi, Maryam; Zarei, Mina; Mushakhian, Siavash; Jafarian, Amirhossein

    2017-01-01

    Introduction: The aim of this animal study was to evaluate the histological response of the new nano zinc-oxide eugenol (NZOE) sealer in comparison with Pulp Canal Sealer (ZOE based) and AH-26 (epoxy resin sealer). Methods and Materials: A total of 27 Wistar rats were used. Four polyethylene tubes were implanted in the back of each rat (three tubes containing the test materials and an empty tube as a control). Then, 9 animals were sacrificed at each interval of 15, 30 and 60 days, and the implants were removed with the surrounding tissues.Samples were evaluated for the presence of inflammatory cell (mononuclear cell), vascular changes, fibrous tissue formation and present of giant cell. Comparisons between groups and time-periods were performed using the Kruskal-Wallis and Mann-Whitney U non-parametric tests. The level of significance was set at 0.05. Results: No significant difference was observed in tissue reactions and biocompatibility pattern of three sealers during 3 experimental periods (P<0.05). In all groups the tissue behavior showed tendency to decrease the irritation effect over time. Conclusion: The new nano zinc-oxide eugenol sealer has histocompatibility properties comparable to conventional commercial sealers. PMID:28179927

  15. Role of quercetin and arginine in ameliorating nano zinc oxide-induced nephrotoxicity in rats

    Directory of Open Access Journals (Sweden)

    Faddah Laila M

    2012-05-01

    Full Text Available Abstract Background Nanoparticles are small-scale substances ( Method ZnO nanoparticles were administered orally in two doses (either 600 mg or 1 g/Kg body weight/day for 5 conscutive days to Wister albino rats. In order to detect the protective effects of the studied antioxidants against n-ZnO induced nepherotoxicity, different biochemical parameters were investigated. Moreover, histopathological examination of kidney tissue was performed. Results Nano zinc oxide-induced nephrotoxicity was confirmed by the elevation in serum inflammatory markers including: tumor necrosis factor alpha (TNF-α, interleukin-6 (IL-6; and C-reactive protein (CRP. Moreover, immunoglobulin (IGg, vascular endothelium growth factor (VEGF, and nitric oxide (NO were significantly increased in rat serum. Serum urea and creatinine levels were also significantly increased in rats intoxicated with n-ZnO particles compared with the control group. Additionally, a significant decrease in the non-enzymatic antioxidant reduced glutathione (GSH was shown in kidney tissues and serum glucose levels were increased. These biochemical findings were supported by a histopathological examination of kidney tissues, which showed that in the animals that received a high dose of n-ZnO, numerous kidney glomeruli underwent atrophy and fragmentation. Moreover, the renal tubules showed epithelial desquamation, degeneration and necrosis. Some renal tubules showed casts in their lumina. Severe congestion was also observed in renal interstitium. These effects were dose dependent. Cotreatment of rats with Qur and/or Arg along with n-ZnO significantly improved most of the deviated tested parameters. Conclusions The data show that Qur has a beneficial effect against n-ZnO oxidative stress and related vascular complications. Also, its combination with Arg proved to be even more effective in ameliorating nano zinc oxide nephrotoxicity.

  16. Catalytic reduction of nitric oxide with carbon monoxide on copper-cobalt oxides supported on nano-titanium dioxide.

    Science.gov (United States)

    Chen, Xia; Zhang, Junfeng; Huang, Yan; Tong, Zhiquan; Huang, Ming

    2009-01-01

    A series of copper-cobalt oxides supported on nano-titanium dioxide were prepared for the reduction of nitric oxide with carbon monoxide and characterized using techniques such as XRD, BET and TPR. Catalyst CuCoOx/TiO2 with Cu/Co molar ratio of 1/2, Cu-Co total loading of 30% at the calcination temperature of 350 degrees C formed CuCo2O4 spinel and had the highest activity. NO conversion reached 98.9% at 200 degrees C. Mechanism of the reduction was also investigated, N2O was mainly yielded below 100 degrees C, while N2 was produced instead at higher temperature. O2 was supposed to accelerate the reaction between NOx and CO for its oxidation of NO to give more easily reduced NO2, but the oxidation of CO by O2 to CO2 decreased the speed of the reaction greatly. Either SO2 or H2O had no adverse impact on the activity of NO reduction; however, in the presence of both SO2 and H2O, the catalyst deactivated quickly.

  17. Are engineered nano iron oxide particles safe? an environmental risk assessment by probabilistic exposure, effects and risk modeling.

    Science.gov (United States)

    Wang, Yan; Deng, Lei; Caballero-Guzman, Alejandro; Nowack, Bernd

    2016-12-01

    Nano iron oxide particles are beneficial to our daily lives through their use in paints, construction materials, biomedical imaging and other industrial fields. However, little is known about the possible risks associated with the current exposure level of engineered nano iron oxides (nano-FeOX) to organisms in the environment. The goal of this study was to predict the release of nano-FeOX to the environment and assess their risks for surface waters in the EU and Switzerland. The material flows of nano-FeOX to technical compartments (waste incineration and waste water treatment plants) and to the environment were calculated with a probabilistic modeling approach. The mean value of the predicted environmental concentrations (PECs) of nano-FeOX in surface waters in the EU for a worst-case scenario (no particle sedimentation) was estimated to be 28 ng/l. Using a probabilistic species sensitivity distribution, the predicted no-effect concentration (PNEC) was determined from ecotoxicological data. The risk characterization ratio, calculated by dividing the PEC by PNEC values, was used to characterize the risks. The mean risk characterization ratio was predicted to be several orders of magnitude smaller than 1 (1.4 × 10(-)(4)). Therefore, this modeling effort indicates that only a very limited risk is posed by the current release level of nano-FeOX to organisms in surface waters. However, a better understanding of the hazards of nano-FeOX to the organisms in other ecosystems (such as sediment) needs to be assessed to determine the overall risk of these particles to the environment.

  18. Bacterial toxicity comparison between nano- and micro-scaled oxide particles

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Wei; Mashayekhi, Hamid [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Stockbridge Hall, Amherst, MA 01003 (United States); Xing Baoshan, E-mail: bx@pssci.umass.ed [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Stockbridge Hall, Amherst, MA 01003 (United States)

    2009-05-15

    Toxicity of nano-scaled aluminum, silicon, titanium and zinc oxides to bacteria (Bacillus subtilis, Escherichia coli and Pseudomonas fluorescens) was examined and compared to that of their respective bulk (micro-scaled) counterparts. All nanoparticles but titanium oxide showed higher toxicity (at 20 mg/L) than their bulk counterparts. Toxicity of released metal ions was differentiated from that of the oxide particles. ZnO was the most toxic among the three nanoparticles, causing 100% mortality to the three tested bacteria. Al{sub 2}O{sub 3} nanoparticles had a mortality rate of 57% to B. subtilis, 36% to E. coli, and 70% to P. fuorescens. SiO{sub 2} nanoparticles killed 40% of B. subtilis, 58% of E. coli, and 70% of P. fluorescens. TEM images showed attachment of nanoparticles to the bacteria, suggesting that the toxicity was affected by bacterial attachment. Bacterial responses to nanoparticles were different from their bulk counterparts; hence nanoparticle toxicity mechanisms need to be studied thoroughly. - Oxide nanoparticles show higher toxicity than their bulk counterparts

  19. Nano-thick calcium oxide armed titanium: boosts bone cells against methicillin-resistant Staphylococcus aureus

    Science.gov (United States)

    Cao, Huiliang; Qin, Hui; Zhao, Yaochao; Jin, Guodong; Lu, Tao; Meng, Fanhao; Zhang, Xianlong; Liu, Xuanyong

    2016-02-01

    Since the use of systemic antibiotics for preventing acute biomaterial-associated infections (BAIs) may build up bacterial resistance and result in huge medical costs and unpredictable mortality, new precaution strategies are required. Here, it demonstrated that titanium armed with a nano-thick calcium oxide layer was effective on averting methicillin-resistant Staphylococcus aureus (MRSA) infections in rabbits. The calcium oxide layer was constructed by, firstly, injecting of metallic calcium into titanium via a plasma immersion ion implantation process, and then transforming the outer most surface into oxide by exposing to the atmosphere. Although the calcium oxide armed titanium had a relative low reduction rate (~74%) in growth of MRSA in vitro, it could markedly promote the osteogenic differentiation of bone marrow stem cells (BMSCs), restore local bone integration against the challenge of MRSA, and decrease the incidence of MRSA infection with a rate of 100% (compared to the titanium control). This study demonstrated for the first time that calcium, as one of the major elements in a human body, could be engineered to avert MRSA infections, which is promising as a safe precaution of disinfection for implantable biomedical devices.

  20. Hyperspectral REE (Rare Earth Element Mapping of Outcrops—Applications for Neodymium Detection

    Directory of Open Access Journals (Sweden)

    Nina Kristine Boesche

    2015-04-01

    Full Text Available In this study, an in situ application for identifying neodymium (Nd enriched surface materials that uses multitemporal hyperspectral images is presented (HySpex sensor. Because of the narrow shape and shallow absorption depth of the neodymium absorption feature, a method was developed for enhancing and extracting the necessary information for neodymium from image spectra, even under illumination conditions that are not optimal. For this purpose, the two following approaches were developed: (1 reducing noise and analyzing changing illumination conditions by averaging multitemporal image scenes and (2 enhancing the depth of the desired absorption band by deconvolving every image spectrum with a Gaussian curve while the rest of the spectrum remains unchanged (Richardson-Lucy deconvolution. To evaluate these findings, nine field samples from the Fen complex in Norway were analyzed using handheld X-ray fluorescence devices and by conducting detailed laboratory-based geochemical rare earth element determinations. The result is a qualitative outcrop map that highlights zones that are enriched in neodymium. To reduce the influences of non-optimal illumination, particularly at the studied site, a minimum of seven single acquisitions is required. Sharpening the neodymium absorption band allows for robust mapping, even at the outer zones of enrichment. From the geochemical investigations, we found that iron oxides decrease the applicability of the method. However, iron-related absorption bands can be used as secondary indicators for sulfidic ore zones that are mainly enriched with rare earth elements. In summary, we found that hyperspectral spectroscopy is a noninvasive, fast and cost-saving method for determining neodymium at outcrop surfaces.

  1. Imaging of room-temperature ferromagnetic nano-domains at the surface of a non-magnetic oxide

    Science.gov (United States)

    Taniuchi, T.; Motoyui, Y.; Morozumi, K.; Rödel, T. C.; Fortuna, F.; Santander-Syro, A. F.; Shin, S.

    2016-06-01

    Two-dimensional electron gases at oxide surfaces or interfaces show exotic ordered states of matter, like superconductivity, magnetism or spin-polarized states, and are a promising platform for alternative oxide-based electronics. Here we directly image a dense population of randomly distributed ferromagnetic domains of ~40 nm typical sizes at room temperature at the oxygen-deficient surface of SrTiO3, a non-magnetic transparent insulator in the bulk. We use laser-based photoemission electron microscopy, an experimental technique that gives selective spin detection of the surface carriers, even in bulk insulators, with a high spatial resolution of 2.6 nm. We furthermore find that the Curie temperature in this system is as high as 900 K. These findings open perspectives for applications in nano-domain magnetism and spintronics using oxide-based devices, for instance through the nano-engineering of oxygen vacancies at surfaces or interfaces of transition-metal oxides.

  2. Facile template-free synthesis of pine needle-like Pd micro/nano-leaves and their associated electro-catalytic activities toward oxidation of formic acid

    Directory of Open Access Journals (Sweden)

    Wang Chuanyi

    2011-01-01

    Full Text Available Abstract Pine needle-like Pd micro/nano-leaves have been synthesized by a facile, template-free electrochemical method. As-synthesized Pd micro/nano-leaves were directly electrodeposited on an indium tin oxide substrate in the presence of 1.0 mM H2PdCl4 + 0.33 M H3PO4. The formation processes of Pd micro/nano-leaves were revealed by scanning electron microscope, and further characterized by X-ray diffraction and electrochemical analysis. Compared to conventional Pd nanoparticles, as-prepared Pd micro/nano-leaves exhibit superior electrocatalytic activities for the formic acid oxidation.

  3. Facile template-free synthesis of pine needle-like Pd micro/nano-leaves and their associated electro-catalytic activities toward oxidation of formic acid

    Science.gov (United States)

    Zhou, Rong; Zhou, Weiqiang; Zhang, Hongmei; Du, Yukou; Yang, Ping; Wang, Chuanyi; Xu, Jingkun

    2011-05-01

    Pine needle-like Pd micro/nano-leaves have been synthesized by a facile, template-free electrochemical method. As-synthesized Pd micro/nano-leaves were directly electrodeposited on an indium tin oxide substrate in the presence of 1.0 mM H2PdCl4 + 0.33 M H3PO4. The formation processes of Pd micro/nano-leaves were revealed by scanning electron microscope, and further characterized by X-ray diffraction and electrochemical analysis. Compared to conventional Pd nanoparticles, as-prepared Pd micro/nano-leaves exhibit superior electrocatalytic activities for the formic acid oxidation.

  4. Research of lignite oxidation kinetic parameters modified by CuSO4 and NaNO3 initiation additives

    Directory of Open Access Journals (Sweden)

    Larionov Kirill

    2017-01-01

    Full Text Available An experimental study and subsequent analytical assessment of activation energy change in lignite oxidation process with addition of NaNO3 and CuSO4 mineral salts were conducted. The results showed that injection of catalytic additives leads to reduction of coal activation energy and reaction initial temperature.

  5. Nickel oxide crystalline nano flakes: synthesis, characterization and their use as anode in lithium-ion batteries

    DEFF Research Database (Denmark)

    Ahmadi, Majid; Younesi, Reza; Vegge, Tejs

    2014-01-01

    Nickel oxide crystalline nano flakes (NONFs)—only about 10 nm wide—were produced using a simple and inexpensive chemistry method followed by a short annealing in ambient air. In a first step, Ni(OH)2 sheets were synthesized by adding sodium hydroxide (NaOH) drop-wise in a Ni(NO3)2 aqueous solutio...

  6. Nano sand filter with functionalized nanoparticles embedded in anodic aluminum oxide templates

    Science.gov (United States)

    Phuong, Nguyenthi; Andisetiawan, Anugrah; van Lam, Do; Kim, Jeong Hwan; Choi, Doo-Sun; Whang, Kyung-Hyun; Nham, Jeasun; Lee, Yun Jung; Yoo, Yeong-Eun; Yoon, Jae Sung

    2016-11-01

    Since the ancient Egyptians had used sand as filter media for water purification, its principle has been inherited through generations and it is still being used now in industries. The sand filter consists of sand literally, and the voids within the sand bed are the pores for filtration. Here we present a filtration principle using nanoparticles, so that the voids between the nanoparticles can be considered as effective pores in nanoscale dimension. Anodic aluminum oxide (AAO) membrane has been used as the working template, and the nanoparticles have been injected and embedded within the pores of the AAO template. Nanoparticles with multiple sizes have been used in order to obtain smaller voids. Moreover, the nanoparticles have been functionalized, or electrically charged, with arginine/phenylalanine (RF) peptide group. In this way, filtration performance for charged particles or molecules, such as methylene blue, has been enhanced. Consequently, this study is expected to provide a new principle for fabrication of nano voids, or nano pores, and for filtration in nanoscale dimension.

  7. Influence of HNO3/H3PO4-NANO2 mediated oxidation on the structure and properties of cellulose fibers.

    Science.gov (United States)

    Xu, Yunhui; Liu, Xin; Liu, Xuelan; Tan, Jiulong; Zhu, Hongling

    2014-10-13

    The bamboo pulp cellulose fiber was oxidized with HNO3/H3PO4-NaNO2 mixture to obtain oxidized cellulose containing different levels of carboxyl content and with high yields. The effects of HNO3/H3PO4-NaNO2 mediated oxidation on structure and properties of the fiber were investigated. The results showed that an increase in carboxyl content and weight loss of oxidized fibers appeared with increasing oxidation time. Compared with the original cellulose, the oxidized fibers had lower crystallinity (29-40%) and thermal stability. The patterns of (13)C NMR, X-ray diffraction and other testing methods revealed that the oxidation mostly occurred at C6 primary hydroxyl groups of cellulose. Moreover, an oxidized fiber with 94.14-98.59% of high yields and 1.13-3.56% of carboxyl content was obtained in the range of oxidation time from 15 to 60 min, while its mechanical properties did not change significantly. This work presented some detailed information about structure-property correlations of oxidized bamboo pulp cellulose fibers and was useful in planning applications of these products.

  8. Photocatalytic Oxidation of Trichloroethylene in Water Using a Porous Ball of Nano-ZnO and Nanoclay Composite

    Directory of Open Access Journals (Sweden)

    Sol-A Bak

    2015-01-01

    Full Text Available The presence of nondegradable organic compounds and xenobiotic chemicals in water is a great concern for the general public because of their polar properties and toxicity. For instance, trichloroethylene (TCE is a widely used solvent in the chemical industry, and it is also a contaminant of soil, surface water, and groundwater. Recent studies on new treatment technologies have shown that photocatalyst-based advanced oxidation processes are appropriate for removing these polar and toxic compounds from water. The objective of this study was to remove TCE from water using novel nano-ZnO-laponite porous balls prepared from photocatalyst ZnO with nanoscale laponite. These nano-ZnO-laponite porous balls have a porosity of approximately 20%. A lower initial concentration of TCE resulted in high removal efficiency. Moreover, the removal efficiency increased with increasing pH in the photocatalytic degradation experiments employing UVC light with nano-ZnO-laponite. The optimal dosage of nano-ZnO-laponite was 30 g and the use of UVC light resulted in a higher removal efficiency than that achieved with UVA light. In addition, the removal efficiency of TCE significantly increased with increasing light intensity. We think that TCE’s removal in water by using porous ball of nano-ZnO and nanoclay composite is a result of degradation from hydroxide by photons of nano-ZnO and physical absorption in nanoclay.

  9. High performance air electrode for solid oxide regenerative fuel cells fabricated by infiltration of nano-catalysts

    Science.gov (United States)

    Lee, Sung-il; Kim, Jeonghee; Son, Ji-Won; Lee, Jong-Ho; Kim, Byung-Kook; Je, Hae-June; Lee, Hae-Weon; Song, Huesup; Yoon, Kyung Joong

    2014-03-01

    A high performance air electrode fabricated by infiltration of highly active nano-catalysts into a porous scaffold is demonstrated for high-temperature solid oxide regenerative fuel cells (SORFCs). The nitrate precursor solution for Sm0.5Sr0.5CoO3 (SSC) catalyst is impregnated into a porous La0.6Sr0.4Co0.2Fe0.8O3 (LSCF)-gadolinia-doped ceria (GDC) composite backbone, and extremely fine SSC nano-particles are uniformly synthesized by in-situ crystallization at the initial stage of SORFC operation via homogeneous nucleation induced by urea decomposition. The SSC nano-catalysts are in the size range of 40-80 nm and stable against coarsening upon the SORFC operation at 750 °C. The electrochemical performance is significantly improved by incorporation of SSC nano-catalysts in both power generation and hydrogen production modes. Systematic analysis on the impedance spectra reveals that the surface modification of the air electrode with nano-catalysts remarkably accelerates the chemical surface exchange reactions for both O2 reduction and O2- oxidation, which are the major limiting processes for SORFC performance.

  10. Production of nano zinc, zinc sulphide and nanocomplex of magnetite zinc oxide by Brevundimonas diminuta and Pseudomonas stutzeri.

    Science.gov (United States)

    Mirhendi, Mansoureh; Emtiazi, Giti; Roghanian, Rasoul

    2013-12-01

    ZnO (Zincite) nanoparticle has many industrial applications and is mostly produced by chemical reactions, usually prepared by decomposition of zinc acetate or hot-injection and heating-up method. Synthesis of semi-conductor nanoparticles such as ZnS (Sphalerite) by ultrasonic was previously reported. In this work, high-zinc tolerant bacteria were isolated and used for nano zinc production. Among all isolated microorganisms, a gram negative bacterium which was identified as Brevundimonas diminuta could construct nano magnetite zinc oxide on bacterial surface with 22 nm in size and nano zinc with 48.29 nm in size. A piece of zinc metal was immersed in medium containing of pure culture of B. diminuta. Subsequently, a yellow-white biofilm was formed which was collected from the surface of zinc. It was dried at room temperature. The isolated biofilm was analysed by X-ray diffractometer. Interestingly, the yield of these particles was higher in the light, with pH 7 at 23°C. To the best of the authors knowledge, this is the first report about the production of nano zinc metal and nano zinc oxide that are stable and have anti-bacterial activities with magnetite property. Also ZnS (sized 12 nm) produced by Pseudomonas stutzeri, was studied by photoluminescence and fluorescent microscope.

  11. A targeted drug delivery system based on dopamine functionalized nano graphene oxide

    Science.gov (United States)

    Masoudipour, Elham; Kashanian, Soheila; Maleki, Nasim

    2017-01-01

    The cellular targeting property of a biocompatible drug delivery system can widely increase the therapeutic effect against various diseases. Here, we report a dopamine conjugated nano graphene oxide (DA-nGO) carrier for cellular delivery of the anticancer drug, Methotrexate (MTX) into DA receptor positive human breast adenocarcinoma cell line. The material was characterized using scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy and UV-vis spectroscopy. Furthermore, the antineoplastic action of MTX loaded DA-nGO against DA receptor positive and negative cell lines were explored. The results presented in this article demonstrated that the application of DA functionalized GO as a targeting drug carrier can improve the drug delivery efficacy for DA receptor positive cancer cell lines and promise future designing of carrier conjugates based on it.

  12. Synthesis and photocatalytic applications of nano-sized zinc-doped mesoporous titanium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Muñoz, Sergio; Pérez-Quintanilla, Damián [Departamento de Química Inorgánica y Analítica, E.S.C.E.T., Universidad Rey Juan Carlos, C/Tulipán s/n, 28933, Móstoles (Madrid) (Spain); Gómez-Ruiz, Santiago, E-mail: santiago.gomez@urjc.es [Departamento de Química Inorgánica y Analítica, E.S.C.E.T., Universidad Rey Juan Carlos, C/Tulipán s/n, 28933, Móstoles (Madrid) (Spain)

    2013-02-15

    Graphical abstract: Nano-sized mesoporous titanium oxide (T0) and zinc-doped nano-sized mesoporous titanium oxides (TA–TD) were synthesized by a simple method and characterized by different techniques. All materials have been studied in the photocatalytic degradation of methylene blue under UV light, observing that the decrease in the band gap of the materials seems to have a positive influence in the photocatalytic activity. Display Omitted Highlights: ► Nano-sized mesoporous TiO{sub 2} and Zn-doped TiO{sub 2} have been synthesized and characterized. ► Band gap of the Zn-doped TiO{sub 2} decreases when the Zn amount increases. ► Materials consist of porous particles (10–20 nm). ► The photocatalytic degradation of MB has been studied for these materials. ► A decrease in the band gap of the materials enhances the photocatalytic activity. -- Abstract: The synthesis of nano-sized mesoporous titanium oxide (T0) is described by an easy synthetic method which consists of the reaction of titanium tetraisopropoxide and a solution of HNO{sub 3} in water (pH 2.0) and the subsequent elimination of the volatiles by simple distillation. On the other hand, zinc-doped mesoporous titanium oxides (TA–TD) were synthesized using the same method but adding increasing amounts of Zn(NO{sub 3}){sub 2} to give materials which contain between 0.12 and 6.17 wt.% Zn. Upon the calcinations of all the obtained materials, characterization has been carried out by using N{sub 2} adsorption–desorption isotherms, powder X-ray diffraction, X-ray fluorescence, UV–vis spectrometry, solid state {sup 47,49}Ti NMR spectroscopy and transmission electronic microscopy (TEM). The results show that all these materials are mesoporous, with BET surfaces between 54 and 121 m{sup 2}/g and similar pore diameters between 6.4 and 9.1 nm. XRD studies show that these materials mainly consist of anatase and very small amounts of brookite. TEM technique shows the small particle sizes of the

  13. Removal of nano and microparticles by granular filter media coated with nanoporous aluminium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Lau, B.L.T.; Harrington, G.W.; Anderson, M.A.; Tejedor, I. [University of Wisconsin, Madison, WI (US). Dept. of Civil & Environmental Engineering

    2004-07-01

    Conventional filtration was designed to achieve high levels of particle and pathogen removal. Previous studies have examined the possibility of modifying filtration media to improve their ability to remove microorganisms and viruses. Although these studies have evaluated filter media coatings for this purpose, none have evaluated nanoscale particle suspensions as coating materials. The overall goal of this paper is to describe the preliminary test results of nanoporous aluminium oxide coated media that can be used to enhance filtration of nano and microparticles. Filtration tests were carried out using columns packed with uncoated and coated forms of granular anthracite or granular activated carbon. A positive correlation between isoelectric pH of filter media and particle removal was observed. The modified filter media with a higher isoelectric pH facilitated better removal of bacteriophage MS2 and 3 {mu}m latex microspheres, possibly due to increased favorable electrostatic interactions.

  14. Removal of nano and microparticles by granular filter media coated with nanoporous aluminium oxide.

    Science.gov (United States)

    Lau, B L T; Harrington, G W; Anderson, M A; Tejedor, I

    2004-01-01

    Conventional filtration was designed to achieve high levels of particle and pathogen removal. Previous studies have examined the possibility of modifying filtration media to improve their ability to remove microorganisms and viruses. Although these studies have evaluated filter media coatings for this purpose, none have evaluated nanoscale particle suspensions as coating materials. The overall goal of this paper is to describe the preliminary test results of nanoporous aluminium oxide coated media that can be used to enhance filtration of nano and microparticles. Filtration tests were carried out using columns packed with uncoated and coated forms of granular anthracite or granular activated carbon. A positive correlation between isoelectric pH of filter media and particle removal was observed. The modified filter media with a higher isoelectric pH facilitated better removal of bacteriophage MS2 and 3 microm latex microspheres, possibly due to increased favorable electrostatic interactions.

  15. Effect of nano-oxide layers on the magnetoresistance of ultrathin permalloy films

    Institute of Scientific and Technical Information of China (English)

    WANG Le; ZHANG Jinzhong; WANG Lijin

    2009-01-01

    Ta/NiFe/Ta ultrathin films with and without nano-oxide layers (NOLs) were prepared by magnetron sputtering followed by a vacuum an-nealing process. The influence of NOLs on the magnetoresistance (MR) ratio of ultrathin permalloy films was studied. The results show that the influence of grain size and textures on the MR ratio becomes weak when the thickness of the NiFe layer is below 15 nm. A higher MR ratio was observed for the thinner (<15 nm) NiFe film with NOLs. The MR ratio of a 10 nm NiFe film can be remarkably enhanced by NOLs. The enhanced MR ratio for these ultrathin films can be attributed to the enhanced specular reflection of conduction electrons.

  16. Nano-scale islands of ruthenium oxide as an electrochemical sensor for iodate and periodate determination.

    Science.gov (United States)

    Chatraei, Fatemeh; Zare, Hamid R

    2013-03-01

    In this study, a promising electrochemical sensor was fabricated by the electrodeposition of nano-scale islands of ruthenium oxide (ruthenium oxide nanoparticles, RuON) on a glassy carbon electrode (RuON-GCE). Then, the electrocatalytic oxidation of iodate and periodate was investigated on it, using cyclic voltammetry, chronoamperometry and amperometry as diagnostic techniques. The charge transfer coefficient, α, and the charge transfer rate constant, ks, for electron transfer between RuON and GCE were calculated as 0.5 ± 0.03 and 9.0 ± 0.7 s(-1) respectively. A comparison of the data obtained from the electrocatalytic reduction of iodate and periodate at a bare GCE (BGCE) and RuON-GCE clearly shows that the unique electronic properties of nanoparticles definitely improve the characteristics of iodate and periodate electrocatalytic reduction. The kinetic parameters such as the electron transfer coefficient, α, and the heterogeneous electron transfer rate constant, k', for the reduction of iodate and periodate at RuON-GCE surface were determined using cyclic voltammetry. Amperometry revealed a good linear relationship between the peak current and the concentration of iodate and periodate. The detection limits of 0.9 and 0.2 μM were calculated for iodate and periodate respectively.

  17. Probing the Nature of Charge Transfer at Nano-Bio Interfaces: Peptides on Metal Oxide Nanoparticles.

    Science.gov (United States)

    Tarakeshwar, Pilarisetty; Palma, Julio L; Holland, Gregory P; Fromme, Petra; Yarger, Jeffery L; Mujica, Vladimiro

    2014-10-16

    Characterizing the nano-bio interface has been a long-standing endeavor in the quest for novel biosensors, biophotovoltaics, and biocompatible electronic devices. In this context, the present computational work on the interaction of two peptides, A6K (Ac-AAAAAAK-NH2) and A7 (Ac-AAAAAAA-NH2) with semiconducting TiO2 nanoparticles is an effort to understand the peptide-metal oxide nanointerface. These investigations were spurred by recent experimental observations that nanostructured semiconducting metal oxides templated with A6K peptides not only stabilize large proteins like photosystem-I (PS-I) but also exhibit enhanced charge-transfer characteristics. Our results indicate that α-helical structures of A6K are not only energetically more stabilized on TiO2 nanoparticles, but the resulting hybrids also exhibit enhanced electron transfer characteristics. This enhancement can be attributed to substantial changes in the electronic characteristics at the peptide-TiO2 interface. Apart from understanding the mechanism of electron transfer (ET) in peptide-stabilized PS-I on metal oxide nanoparticles, the current work also has implications in the development of novel solar cells and photocatalysts.

  18. Microstructural Effects on the Reactivity of Nano-Aluminum/Iodine (V) Oxide Films

    Science.gov (United States)

    Little, Brian; Langhals, Jarred; Emery, Sam; Martinez, Lucas; Welle, Eric; Lindsay, Michael

    2015-06-01

    Recent efforts investigating the self-ignition mechanism of nanoaluminum blended with iodine (V) oxide in the form of powders with and without additives suggests that ignition begins below the decomposition point of either reactant and takes place at the alumina shell surrounding the aluminum nanoparticle. As observed in previous studies of powder composites, microstructural features such as particle morphology are expected to strongly influence properties that govern the combustion behavior of this energetic material (EM). In this study, highly reactive composites containing amorphous and/or crystalline iodine oxide and nano-sized Al was blended with an additive and deposited as films. Physiochemical techniques such as thermal gravimetric analysis, scanning calorimetry, X-ray diffraction, electron microscopy, high-speed imaging, time of arrival data via photodiodes and planar doppler velocimetry were employed to characterize these EMs with emphasis on correlating the reaction rate (burn rate) with inherent microstructural features (porosity, thickness, TMD, etc). This work was a continuation of efforts to probe the self-ignition mechanism of Al-iodine (V) oxide composites.

  19. Aerosol synthesis of nano and micro-scale zero valent metal particles from oxide precursors

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Jonathan [Los Alamos National Laboratory; Luhrs, Claudia [UNM; Lesman, Zayd [UNM; Soliman, Haytham [UNM; Zea, Hugo [UNM

    2010-01-01

    In this work a novel aerosol method, derived form the batch Reduction/Expansion Synthesis (RES) method, for production of nano / micro-scale metal particles from oxides and hydroxides is presented. In the Aerosol-RES (A-RES) method, an aerosol, consisting of a physical mixture of urea and metal oxide or hydroxides, is passed through a heated oven (1000 C) with a residence time of the order of 1 second, producing pure (zero valent) metal particles. It appears that the process is flexible regarding metal or alloy identity, allows control of particle size and can be readily scaled to very large throughput. Current work is focused on creating nanoparticles of metal and metal alloy using this method. Although this is primarily a report on observations, some key elements of the chemistry are clear. In particular, the reducing species produced by urea decomposition are the primary agents responsible for reduction of oxides and hydroxides to metal. It is also likely that the rapid expansion that takes place when solid/liquid urea decomposes to form gas species influences the final morphology of the particles.

  20. Adsorption Kinetic Properties of As(III) on Synthetic Nano Fe-Mn Binary Oxides

    Institute of Scientific and Technical Information of China (English)

    Mei Yu; Yanxin Wang; Shuqiong Kong; Evalde Mulindankaka; Yuan Fang; Ya Wu

    2016-01-01

    The adsorptive removal of arsenic by synthetically-prepared nano Fe-Mn binary oxides (FM) was investigated. A novel method using potassium permanganate and ferric chloride as raw materials was used to synthesise FM. The molar ratio of Fe and Mn in the synthetic Fe-Mn binary oxides was 4 : 3. The FM-1 and FM-2 (prepared at different activation temperatures) having high specific surface areas (358.87 and 128.58 m2/g, respectively) were amorphous and of nano particle types. The amount of arsenic adsorbed on FM-1 was higher than that adsorbed on FM-2 particles. After adsorption by FM-1, residual arsenic concentration decreased to less than 10μg/L. The adsorption kinetics data were analyzed using different kinetic models including pseudofirst-order model, pseudo second-order model, Elovich model and in-traparticle diffusion model. Pseudo second-order kinetic model was the most appropriate model to describe the adsorption kinetics. The adsorption percentage of As(III) increased in the pH range of 2–3 while it de-creased with the increase of pH ( 3

  1. Ductility Enhancement of Molybdenum Phase by Nano-sized Oxide Dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Bruce

    2008-07-18

    The objective of this research is to understand and to remedy the impurity effects for room-temperature ductility enhancement of molybdenum (Mo) based alloys by the inclusion of nano-sized metal oxide dispersions. This research combines theoretical, computational, and experimental efforts. The results will help to formulate systematic strategies in searching for better composed Mo-based alloys with optimal mechanical properties. For this project, majority of the research effort was directed to atomistic modeling to identify the mechanisms responsible for the oxygen embrittling and ductility enhancement based on fundamental electronic structure analysis. Through first principles molecular dynamics simulations, it was found that the embrittling impurity species were attracted to the metal oxide interface, consistent with previous experiments. Further investigation on the electronic structures reveals that the presence of embrittling species degrades the quality of the metallic chemical bonds in the hosting matrix in a number of ways, the latter providing the source of ductility. For example, the spatial flexibility of the bonds is reduced, and localization of the impurity states occurs to pin the dislocation flow. Rice’s criterion has been invoked to explain the connections of electronic structure and mechanical properties. It was also found that when impurity species become attracted to the metal oxide interface, some of the detrimental effects are alleviated, thus explaining the observed ductility enhancement effects. These understandings help to develop predictive capabilities to facilitate the design and optimization of Mo and other high temperature alloys (e.g. ODS alloys) for fossil energy materials applications. Based on the theoretical and computational studies, the experimental work includes the preparation of Mo powders mixed with candidate nano-sized metal oxides, which were then vacuum hot-pressed to make the Mo alloys. Several powder mixing methods

  2. Evaluation of the sonosensitizing properties of nano-graphene oxide in comparison with iron oxide and gold nanoparticles

    Science.gov (United States)

    Beik, Jaber; Abed, Ziaeddin; Shakeri-Zadeh, Ali; Nourbakhsh, Mitra; Shiran, Mohammad Bagher

    2016-07-01

    In cancer hyperthermia, ultrasound is considered as an appropriate source of energy to achieve desired therapeutic levels of heating. It is assumed that such a heating is targeted to cancer cells by using nanoparticles as sonosensitization agents. Here, we report the sonosensitizing effects of Nano-Graphene Oxide (NGO) and compare them with gold nanoparticles (AuNPs), Iron Oxide nanoparticles (IONPs). Experiments were conducted to explore the effects of nanoparticle type and concentration, as well as ultrasound power, on transient heating up of the solutions exposed by 1 MHz ultrasound. Nanoparticles concentration was selected from 0.25 to 2.5 mg/ml and the solutions were exposed by ultrasound powers from 1 to 8 W. Real time temperature monitoring was done by a thermocouple and obtained data was analyzed. Temperature profiles of various nanoparticle solutions showed the higher heating rates, in comparison to water. Heating rise was strongly depended on nanoparticles concentration and ultrasound power. AuNPs showed a superior efficiency in heat generation enhancement in comparison to IONPs and NGO. Our result supports the idea of sonosensitizing capabilities of AuNPs, IONPs, and NGO. Targeted hyperthermia may be achievable by preferential loading of tumor with nanoparticles and subsequent ultrasound irradiation.

  3. Separating nano graphene oxide from the residual strong-acid filtrate of the modified Hummers method with alkaline solution

    Science.gov (United States)

    Hu, Xuebing; Yu, Yun; Wang, Yongqing; Zhou, Jianer; Song, Lixin

    2015-02-01

    In the modified Hummers method for preparing graphene oxide, the yellow slurry can be obtained. After filtering through a quantitative filter paper, the strong-acid filtrate containing the unprecipitated nano graphene oxide was gained. The corresponding filtrate was added gradually with an alkaline (NaOH or KOH) solution at room temperature. The unprecipitated nano graphene oxide could undergo fast aggregation when the pH value of the filtrate was about 1.7 and formed the stable floccules. X-ray diffraction analysis shows the dominant peak of the floccules is about 11°, which accords to the peak of graphene oxide. Spectra of X-ray photoelectron spectroscopy confirm the presence in the floccules of an abundance of oxygen functional groups and the purified graphene oxide floccules can be obtained. Atomic force microscopy measurement shows the graphene oxide floccules consists of sheet-like objects, mostly containing only a few layers (about 5 layers). Zeta potential analysis demonstrates the surface charge of the graphene oxide is pH-sensitive and its isoelectric point is ∼1.7. The flocculation mechanism of graphene oxide ascribes to the acid-base interaction with the surface functional groups of the carbon layers.

  4. Nano-scale islands of ruthenium oxide as an electrochemical sensor for iodate and periodate determination

    Energy Technology Data Exchange (ETDEWEB)

    Chatraei, Fatemeh; Zare, Hamid R., E-mail: hrzare@yazd.ac.ir

    2013-03-01

    In this study, a promising electrochemical sensor was fabricated by the electrodeposition of nano-scale islands of ruthenium oxide (ruthenium oxide nanoparticles, RuON) on a glassy carbon electrode (RuON-GCE). Then, the electrocatalytic oxidation of iodate and periodate was investigated on it, using cyclic voltammetry, chronoamperometry and amperometry as diagnostic techniques. The charge transfer coefficient, {alpha}, and the charge transfer rate constant, k{sub s}, for electron transfer between RuON and GCE were calculated as 0.5 {+-} 0.03 and 9.0 {+-} 0.7 s{sup -1} respectively. A comparison of the data obtained from the electrocatalytic reduction of iodate and periodate at a bare GCE (BGCE) and RuON-GCE clearly shows that the unique electronic properties of nanoparticles definitely improve the characteristics of iodate and periodate electrocatalytic reduction. The kinetic parameters such as the electron transfer coefficient, {alpha}, and the heterogeneous electron transfer rate constant, k Prime , for the reduction of iodate and periodate at RuON-GCE surface were determined using cyclic voltammetry. Amperometry revealed a good linear relationship between the peak current and the concentration of iodate and periodate. The detection limits of 0.9 and 0.2 {mu}M were calculated for iodate and periodate respectively. Highlights: Black-Right-Pointing-Pointer Ruthenium oxide nanoparticles, RuON, were used for electrocatalytic reduction iodate and periodate. Black-Right-Pointing-Pointer Formal potential, E{sup 0} Prime , of the surface redox couple of RuON is pH-dependent. Black-Right-Pointing-Pointer The heterogeneous electron transfer rate constant values between both analytes and RuON were calculated.

  5. Nano/micro tribological behaviors of a self-assembled graphene oxide nanolayer on Ti/titanium alloy substrates

    Science.gov (United States)

    Li, Peng Fei; Zhou, Hua; Cheng, Xian-Hua

    2013-11-01

    In this study, reduced graphene oxide (RGO) layer is prepared on a self-assembled monolayer (SAM) of 3-aminopropyltriethoxysilane (APTES) modified surface of deposited Ti substrates or Ti-29Nb-13Ta-4.6Zr (TNTZ) alloy substrate. The surface morphology was measured by SEM and AFM. Tribological behaviors in nano scale by AFM and in micro scale by UMT-2 were investigated and compared with titanium substrate, APTES SAM and GO-APTES nanolayer. XPS, water contact angle (WCA) and ellipsometry tests were carried out as assistant methods to discuss the tribological mechanisms. In both nano and micro scale tribological tests, the prepared film holds remarkable tribological properties. It also shows good anti-wear performance in our designed bio-tribological test. Nano and micro tribological mechanisms of the film are discussed.

  6. Cryogenic optical nano-imaging of phase coexistence in correlated oxides

    Science.gov (United States)

    McLeod, A. S.; van Heumen, E.; Zhang, J.; Ramirez, J. G.; Huang, Z.; Wang, S.; Saerbeck, T.; Guenon, S.; Goldflam, M.; Anderegg, L.; Kelly, P.; Mueller, A.; Liu, M. K.; Wu, W. B.; Avert, R. D.; Schuller, I. K.; Basov, D. N.

    Correlated transition metal oxides exhibit a bevy of textbook electronic phases characterized by richly interacting lattice, spin, and orbital degrees of freedom. A broad array of accessible thermodynamic phases, ranging from Mott insulator to superconductor, enables abrupt transitions in physical and electronic properties under modest external stimuli, accompanied by spontaneous phase coexistence at the nano-scale. We present a novel near-field optical scanning probe capable of resolving the electronic character of such ``switched'' phases in the coexistent regime, even insulators, at 10 nm resolution and down to liquid helium temperatures. We demonstrate variable-temperature optical, structural, and magnetic imaging functionalities through studies of the insulator-metal transition in two prototypic correlated oxides under epitaxial strain. Structural and electronic attributes of the Mott transition are distinguished in a V2O3 thin film, whereas metastable electronic and magnetic phase coexistence is revealed across a 200K range in the strained manganite La0.67Ca0.33MnO3

  7. Poly(ethylene glycol) conjugated nano-graphene oxide for photodynamic therapy

    Institute of Scientific and Technical Information of China (English)

    Pilger; FRANK

    2010-01-01

    A novel methoxy-poly(ethylene glycol) modified nano-graphene oxide(NGO-mPEG) was designed and synthesized as a photosensitizer(PS) carrier for photodynamic therapy of cancer.NGO with a size below 200 nm was prepared using a modified Hummers’ method.NGO was observed by AFM to exhibit a structure with single-layer graphene oxide sheets down to a few nanometers in height.Hydrophilic mPEG conjugation of NGO(NGO-mPEG) was found to enhance solubility in cell culture media.No apparent cytotoxicity of the NGO-mPEG was observed towards MCF-7 carcinoma cell line.Zinc phthalocyanine(ZnPc),a photosensitizer for photodynamic therapy,was loaded in the NGO-PEG through π-π stacking and hydrophobic interactions,with the drug loading efficiency up to 14 wt%.Hydrophobic ZnPc was internalized in MCF-7 cells,exhibiting a pronounced phototoxicity in the cells under Xe light irradiation.The results indicate a great potential of NGO-mPEG for photodynamic therapy of cancer.

  8. Synthesis and characterization of mesoporous and nano-crystalline phosphate zirconium oxides

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Enriquez, J.M., E-mail: jmanuelher@hotmail.co [Instituto Tecnologico de Cd. Madero, Division de Estudios de Posgrado e Investigacion, Juventino Rosas y Jesus Urueta S/N, Col. Los Mangos, 89440 Cd. Madero, Tam. (Mexico); Cortez Lajas, L.A.; Garcia Alamilla, R.; Castillo Mares, A.; Sandoval Robles, G. [Instituto Tecnologico de Cd. Madero, Division de Estudios de Posgrado e Investigacion, Juventino Rosas y Jesus Urueta S/N, Col. Los Mangos, 89440 Cd. Madero, Tam. (Mexico); Garcia Serrano, L.A. [Instituto Politecnico Nacional, Escuela Superior de Ingenieria Textil, Av. Instituto Politecnico Nacional s/n, Edificio 8, Col. Linda Vista, Delegacion Gustavo A. Madero, 07738 Mexico, D.F. (Mexico)

    2009-08-26

    In this work the preparation and characterization of the materials such as zirconia (ZrO{sub 2}) and zirconia promoted with phosphate ion (ZrO{sub 2}-PO{sub 4}{sup 3-}) is presented. Pure zirconium hydroxide [Zr(OH){sub 4}] was synthesized by the sol-gel method using precursors such as zirconium n-butoxide and 1-butanol maintaining a pH 8 during the synthesis. Zr(OH){sub 4} was impregnated with 15 wt.% of the acid agent. Both were calcined in a dynamic air atmosphere for 3 h at 400, 500 and 600 deg. C. The supports were characterized by thermal analysis, X-ray diffraction, nitrogen physisorption as well as infrared spectroscopy. The results showed a positive effect on the physicochemical properties of the catalytic supports after Zr(OH){sub 4} impregnation with the dopping agent (H{sub 3}PO{sub 4}). Phosphate zirconium oxides remained thermically stable after calcination. It was observed that the dopping agent remained firmly attached to the zirconium oxide surface, inhibiting the particle growth and delaying the syntherization of the material and the apparition of the monoclinic phase, obtaining mesoporous and nano-crystalline materials (crystallite size 1.0-6.5 nm) with high surface areas (210-329 m{sup 2}/g) and tetragonal structure defined for the calcination temperature of 600 deg. C.

  9. The need for nano-scale modeling in solid oxide fuel cells.

    Science.gov (United States)

    Ryan, E M; Recknagle, K P; Liu, W; Khaleel, M A

    2012-08-01

    Solid oxide fuel cells (SOFCs) are high temperature fuel cells, which are being developed for large scale and distributed power systems. SOFCs promise to provide cleaner, more efficient electricity than traditional fossil fuel burning power plants. Research over the last decade has improved the design and materials used in SOFCs to increase their performance and stability for long-term operation; however, there are still challenges for SOFC researchers to overcome before SOFCs can be considered competitive with traditional fossil fuel burning and renewable power systems. In particular degradation due to contaminants in the fuel and oxidant stream is a major challenge facing SOFCs. In this paper we discuss ongoing computational and experimental research into different degradation and design issues in SOFC electrodes. We focus on contaminants in gasified coal which cause electrochemical and structural degradation in the anode, and chromium poisoning which affects the electrochemistry of the cathode. Due to the complex microstructures and multi-physics of SOFCs, multi-scale computational modeling and experimental research is needed to understand the detailed physics behind different degradation mechanisms, the local conditions within the cell which facilitate degradation, and its effects on the overall SOFC performance. We will discuss computational modeling research of SOFCs at the macro-, meso- and nano-scales which is being used to investigate the performance and degradation of SOFCs. We will also discuss the need for a multi-scale modeling framework of SOFCs, and the application of computational and multi-scale modeling to several degradation issues in SOFCs.

  10. Manufacturing and characterisation of PMMA-graphene oxide (GO nanocomposite sandwich films with electrospun nano-fibre core

    Directory of Open Access Journals (Sweden)

    D. Bhattacharyya

    2012-12-01

    Full Text Available Purpose: Nanocomposite materials, comprising of polymer matrices and nano-sized reinforcements, exhibit significantly enhanced mechanical and functional properties at extremely low filler loading. In recent years, graphene oxide (GO has emerged as a new class of low cost nano-filler with high mechanical strength and stiffness, and alterable electrical properties. For nano-fillers with layered structure like GO, complete exfoliation and uniform dispersion of filler in the polymer matrices is essential to enhance the matrix-filler interaction and in turn the mechanical and/or functional property improvement. Conventional nanocomposite manufacturing methods including in-situ polymerisation and solvent processing encounter the problem of agglomeration of GO films. Additionally, its low bulk density presents difficulties in handling, and the energy requirement for mechanical mixing and extrusion processes is very high. In this work, we report manufacturing of poly(methyl methacrylate–graphene oxide (PMMA-GO nano-fibre mat using relatively novel approach of employing electrospinning technique. The manufactured electrospun core was inserted between plain polymer layers to prepare a robust and easy to handle sandwich film. Morphology and structure of the PMMA-GO nano-fibre cores was evaluated with scanning and transmission electron microscopy and X-ray diffractometry. The manufactured nano-fibre mat samples exhibited uniform diameter and dispersion. The functional parameters including thermal stability and gas barrier were evaluated with differential scanning calorimetry and oxygen permeation testing, and these functional properties were observed to be superior to that of monolithic polymer counterparts.

  11. The role of particle size of particulate nano-zinc oxide wood preservatives on termite mortality and leach resistance

    Directory of Open Access Journals (Sweden)

    Kartal S Nami

    2011-01-01

    Full Text Available Abstract Historically most residential wood preservatives were aqueous soluble metal formulations, but recently metals ground to submicron size and dispersed in water to give particulate formulations have gained importance. In this study, the specific role nano-zinc oxide (ZnO particle size and leach resistance plays in termite mortality resulting from exposure to particulate ZnO-treated wood was investigated. Southern yellow pine (SYP sapwood impregnated with three concentrations of two particle sizes (30 and 70 nm of ZnO were compared to wood treated with soluble zinc sulphate (ZnSO4 preservative for leach resistance and termite resistance. Less than four percent leached from the particulate nano-ZnO-treated specimens, while 13 to 25% of the zinc sulphate leached from the soluble treated wood. Nano-ZnO was essentially non-leachable from wood treated with 5% formulation for the 30-nm particle size. In a no-choice laboratory test, eastern subterranean termites (Reticulitermes flavipes consumed less than 10% of the leached nano-ZnO-treated wood with 93 to 100% mortality in all treatment concentrations. In contrast, termites consumed 10 to 12% of the leached ZnSO4-treated wood, but with lower mortality: 29% in the 1% treatment group and less than 10% (5 and 8%, respectively in the group of wood blocks treated with 2.5 and 5.0% ZnSO4. We conclude that termites were repelled from consuming wood treated with nano-ZnO, but when consumed it was more toxic to eastern subterranean termites than wood treated with the soluble metal oxide formulation. There were no differences in leaching or termite mortality between the two particle sizes of nano-ZnO.

  12. Films, Needles, and Particles: A Comparative Study on the Ferroic Properties of Complex Oxides Nano-Structured in One, Two, and Three Dimensions

    Science.gov (United States)

    2014-03-01

    complex oxides have been observed to possess the properties of insulators , semiconductors, semimetals, metals, and superconductors (3). Ferroic and...are varied independently. To study the film-to- nano-needle and film-to-nano-particle transitions , we have designed Metal- Insulator -Metal (MIM...9 4. Conclusions 11 5. References 12 6. Transitions 14 6.1 Patent Disclosure

  13. Modeling Optical and Electronic Properties of Silica Nano-Clusters in Silicon Rich Oxide Films

    Directory of Open Access Journals (Sweden)

    N.D. Espinosa-Torres

    2013-07-01

    Full Text Available Quantum effects are very important in nano scale systems such as molecules and clusters constituted of particles from a few to hundreds or a few thousands of atoms. Their optical and electronic properties are often dependent on the size of the systems and the way in which the atoms in these molecules or clusters are bonded. Generally, these nano-structures display optical and electronic properties significantly different of the bulk materials. Silica agglomerates expected in Silicon Rich Oxide (SRO films have optical properties, which depend directly on size, and their rationalization can lead to new applications with a potential impact on many fields of science and technology. On the other hand, the room temperature photoluminescence (PL of Si : SiO2 or Si : SiOx structures usually found in SRO has recently generated an enormous interest due to their possible applications in optoelectronic devices. However, the understanding of the emission mechanism is still under debate. In this research, we employed the Density Functional Theory with a functional B3LYP and a basis set 6-31 G* to calculate the electronic and optical properties of molecules and clusters of silicon dioxide. With the theoretical calculation of the structural and optical properties of silicon dioxide clusters is possible to evaluate the contribution of silica in the luminescent emission mechanism experimentally found in thin SRO films. It was found that silica contribution to the luminescent phenomenon in SRO thin films is less important than that of the silicon monoxide agglomerates because the number of silica structures, which may show emission in the visible spectrum, is much lower [1], compared to the number of silicon monoxide structures which emit in this region.

  14. Determination of the Potential Barrier at the Metal/Oxide Interface in a Specular Spin Valve Structure with Nano-oxide Layers Using Electron Holography

    Institute of Scientific and Technical Information of China (English)

    王岩国; 沈峰; 张泽; 蔡建旺; 赖武彦

    2002-01-01

    The local potential distribution in a specular spin valve structure with nano-oxide layers has been mapped byusing off-axis electron holography in a field emission gun transmission electron microscope. A potential jumpof 3-4 V across the metal/oxide interface was detected for the first time. The presence of the potential barrierconfirms the formation of the metal/insulator/metal structure, which contributes to the increasing mean free pathof spin-polarized electrons via the specular reflection of spin-polarized electrons at the metal/oxide interface. Itleads to nearly double enhancement of the magnetoresistance ratio from 8% to 15%.

  15. Preparation, spectral and thermal studies of neodymium zirconyl oxalate hexahydrate

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, V.B.; Mehrotra, P.N. (Roorkee Univ. (India). Dept. of Chemistry)

    Neodymium zirconyl oxalate (NdZrOX) is prepared and characterized by chemical analysis and IR spectral studies. Its thermal decomposition was investigated using DTA, TG, DTG, x-ray diffraction and IR spectroscopy. Based on thermogravimetry and isothermal studies a probable mechanism for the decomposition is proposed. The decomposition proceeds mainly through three stages: dehydration between RT-413 K; decomposition of oxalate between 413-943 K; and decomposition of the carbonate between 1028-1235 K to give a mixed oxide. The IR spectra and x-ray diffraction studies are made for identification of the intermediates. X-ray diffraction studies of the end product indicates that it belongs to cubic crystal system.

  16. Transport properties of Gum mediated synthesis of Indium Oxide (In2O3 Nano fluids

    Directory of Open Access Journals (Sweden)

    Ch. Kanchana Latha

    2016-01-01

    Full Text Available Two- Step method has been applied to prepare stable In2O3 nano fluids in Ethylene Glycol with PVP (Polyvinyl pyrrolidone used as stabilizing agent having In2O3 concentrations of 1% by volume, where the In2O3 nano particles are obtained by biosynthesis of Indium (III Acetyl Acetonate and Gum Acacia. Since the two-step method is more versatile as it provides the opportunity to disperse a wide variety of nano particles in different types of base fluids. The nano fluids were characterised by UV-vis spectroscopy, FTIR, SEM, EDAX, and TEM, and systematically investigated for Thermal conductivity (TC, density, viscosity, specific gravity and electrical conductivity for different polymer concentrations. The size of nano particles was found to be in the range of 5-30nm for two different nano particle to PVP ratios. For higher concentration of polymer in nano fluid, nano particles were 20nm in size showing increase in Thermal conductivity but a decrease in density and viscosity which is due to the polymer structure around nano particles. It is observed that the viscosity, density & specific gravity increases with the increase in PVP concentration and decreases with temperature. The thermal conductivity measurements of nano fluids show substantial increment relative to the base fluid (Ethylene glycol. Effect of PVP Polymer on viscosity, density, specific gravity can have a significant effect on magnitude and behaviour of the Thermal conductivity enhancement confirming the Newtonian behaviour of nano fluid. This offers tremendous scope for developing compact and effective heat transfer equipment. An enhancement of 20-25% for 1:5 volume concentration are observed at an average voltage of 60V when compared with EG (Ethylene glycol at the same voltage. This method is simple, fast and reliable for the synthesis of Newtonian nano fluids containing In2O3 nano particles.

  17. New approach on the catalytic oxidation of methanol to formaldehyde over MoO3 supported on nano hydroxyapatite catalysts

    Science.gov (United States)

    Said, A. A.; Abd El-Wahab, M. M.; Alian, A. M.

    2014-08-01

    Molybdenum oxide (20 wt. %) supported on nano hydroxyapatite mixed was prepared by impregnation method and calcinated at 400° 500° 600° and 700°C in static air atmosphere. The catalysts were characterized by thermogravimetry (TG), differential thermal analysis (DTA), X-ray diffraction (XRD), Transmission Electron Microscope (TEM) and nitrogen sorption measurements. The gas-phase oxidation of methanol to formaldehyde was carried out in a conventional fixed flow bed reactor. The obtained results clearly revealed that the formation of CaMoO4 spinel nano particles was active and selective catalyst towards the formation of formaldehyde. The maximum yield of formaldehyde was 97% on the catalyst calcined at 400 ° C. Moreover, the yield of formaldehyde was found unaffected by increasing the calcination temperature up to 700° C.

  18. Laterally configured resistive switching device based on transition-metal nano-gap electrode on Gd oxide

    Energy Technology Data Exchange (ETDEWEB)

    Kawakita, Masatoshi; Okabe, Kyota [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan); Kimura, Takashi [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan); Research Center for Quantum Nano-Spin Sciences, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan)

    2016-01-11

    We have developed a fabrication process for a laterally configured resistive switching device based on a Gd oxide. A nano-gap electrode connected by a Gd oxide with the ideal interfaces has been created by adapting the electro-migration method in a metal/GdO{sub x} bilayer system. Bipolar set and reset operations have been clearly observed in the Pt/GdO{sub x} system similarly in the vertical device based on GdO{sub x}. Interestingly, we were able to observe a clear bipolar switching also in a ferromagnetic CoFeB nano-gap electrode with better stability compared to the Pt/GdO{sub x} device. The superior performance of the CoFeB/GdO{sub x} device implies the importance of the spin on the resistive switching.

  19. Morphology, thermal, electrical and electrochemical stability of nano aluminium-oxide-filled polyvinyl alcohol composite gel electrolyte

    Indian Academy of Sciences (India)

    Navin Chand; Neelesh Rai; S L Agrawal; S K Patel

    2011-12-01

    In the present work, an attempt has been made to develop nano aluminium oxide (Al2O3)-filled polyvinyl alcohol (PVA) composite gel electrolytes. Surface morphological studies, thermal behaviour, electrochemical stability and electrical characterization of these composite gel electrolytes have been performed. An increase in the concentration of Al2O3 in composite gel electrolytes increases the amorphous characteristics of pure PVA. Bulk conductivity of composite gel electrolytes increases by an order of magnitude on addition of a nano filler. Maximum conductivity of 5.81 × 10-2 S/cm is observed for 6 wt% Al2O3-filled polymer gel composite electrolytes. Temperature dependence of electrical conductivity shows a combination of Arrhenius and Vogel–Tamman–Fulcher (VTF) nature. Maximum current stability during oxidation and reduction cycle is noticed for 6 wt% Al2O3-filled PVA composite electrolyte, viz. ±1.65 V.

  20. Comparative toxicity of copper oxide bulk and nano particles in Nile Tilapia; Oreochromis niloticus: Biochemical and oxidative stress

    Directory of Open Access Journals (Sweden)

    Amr A. Abdel-Khalek

    2015-10-01

    Full Text Available Nile Tilapia; Oreochromis niloticus are commonly used in the assessment of aquatic environment quality and also considered as useful bio-indicators during environmental pollution monitoring. The LC50/96 h of copper oxide (bulk & nano particles [CuO (BPs & NPs] were 2205 & 150 mg/l, respectively. Two tested concentrations of CuO (BPs & NPs were selected: the first concentration was equivalent to (1/10 (220.5 & 15 mg/l, and the second was equivalent to (1/20 (110.25 & 7.5 mg/l LC50/96 h·CuO (BPs & NPs, respectively. While serum glucose, liver function tests (AST, ALT and ALP and kidney function tests (creatinine and uric acid showed a significant increase, serum total proteins, albumin, globulin and total lipids showed a significant decrease. Both liver and gill tissues of the studied fish showed a reduction in GSH content and an elevation in MDA and GPx activities. The present study also showed an elevation in liver CAT & SOD activities when exposed to both concentrations of CuO BPs and in the case of gills when exposed to both concentrations of CuO (BPs & NPs, although activity of these enzymes showed an inhibition in the liver when exposed to both concentrations of CuO NPs. The present study investigated whether CuO NPs are more toxic than CuO BPs.

  1. Effects of acetic acid on microstructure and electrochemical properties of nano cerium oxide films coated on AA7020-T6 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    H. Hasannejad; T. Shahrabi; M. Aliofkhazraei

    2009-01-01

    Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), crack-flee films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.

  2. The influence of the capping agent on the oxidation of silver nanoparticles: nano-impacts versus stripping voltammetry.

    Science.gov (United States)

    Toh, Her Shuang; Jurkschat, Kerstin; Compton, Richard G

    2015-02-09

    The influence of capping agents on the oxidation of silver nanoparticles was studied by using the electrochemical techniques of anodic stripping voltammetry and anodic particle coulometry ("nano-impacts"). Five spherical silver nanoparticles each with a different capping agent (branched polyethylenimine (BPEI), citrate, lipoic acid, polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP)) were used to perform comparative experiments. In all cases, regardless of the capping agent, complete oxidation of the single nanoparticles was seen in anodic particle coulometry. The successful quantitative detection of the silver nanoparticle size displays the potential application of anodic particle coulometry for nanoparticle characterisation. In contrast, for anodic stripping voltammetry using nanoparticles drop casting, it was observed that the capping agent has a very significant effect on the extent of silver oxidation. All five samples gave a low oxidative charge corresponding to partial oxidation. It is concluded that the use of anodic stripping voltammetry to quantify nanoparticles is unreliable, and this is attributed to nanoparticle aggregation.

  3. Hydrogen production by ethanol partial oxidation over nano-iron oxide catalysts produced by chemical vapour synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Wael Ahmed Abou Taleb Sayed

    2011-01-13

    This work presents the experimental results of the synthesis of unsupported and supported SiC iron oxide nanoparticles and their catalytic activity towards ethanol partial oxidation. For comparison, further unsupported iron oxide phases were investigated towards the ethanol partial oxidation. These {gamma}-Fe{sub 2}O{sub 3} and {alpha}/{gamma}-Fe{sub 2}O{sub 3} phase catalysts were prepared by the CVS method using Fe(CO){sub 5} as precursor, supplied by another author. The {alpha}-Fe{sub 2}O{sub 3} and SiC nanoparticles were prepared by the CVS method using a home made hot wall reactor technique at atmospheric pressure. Ferrocene and tetramethylsilane were used as precursor for the production process. Process parameters of precursor evaporation temperature, precursor concentration, gas mixture velocity and gas mixture dilution were investigated and optimised to produce particle sizes in a range of 10 nm. For Fe{sub 2}O{sub 3}/SiC catalyst series production, a new hot wall reactor setup was used. The particles were produced by simultaneous thermal decomposition of ferrocene and tetramethylsilane in one reactor from both sides. The production parameters of inlet tube distance inside the reactor, precursor evaporation temperature and carrier gas flow were investigated to produce a series of samples with different iron oxide content. The prepared catalysts composition, physical and chemical properties were characterized by XRD, EDX, SEM, BET surface area, FTIR, XPS and dynamic light scattering (DLS) techniques. The catalytic activity for the ethanol gas-phase oxidation was investigated in a temperature range from 260 C to 290 C. The product distributions obtained over all catalysts were analysed with mass spectrometry analysis tool. The activity of bulk Fe{sub 2}O{sub 3} and SiC nanoparticles was compared with prepared nano-iron oxide phase catalysts. The reaction parameters, such as reaction temperature and O{sub 2}/ethanol ratio were investigated. The catalysts

  4. Adsorption of heavy metal ion from aqueous solution by nickel oxide nano catalyst prepared by different methods

    Directory of Open Access Journals (Sweden)

    Amira M. Mahmoud

    2015-03-01

    Full Text Available Environmental pollution by heavy metal is arising as the most endangering tasks to both water sources and atmosphere quality today. The treatment of heavy metals is of special concern due to their recalcitrance and persistence in the environment. To limit the spread of the heavy metals within water sources, nickel oxide nanoparticles adsorbents were synthesized and characterized with the aim of removal of one of the aggressive heavy elements, namely; lead ions. Nano nickel oxide adsorbents were prepared using NaOH and oxalic acid dissolved in ethanol as precursors. The results indicated that adsorption capacity of Pb(II ion by NiO-org catalyst is favored than that prepared using NaOH as a precipitant. Nickel oxide nanoparticles prepared by the two methods were characterized structurally and chemically through XRD, DTA, TGA, BET and FT-IR. Affinity and efficiency sorption parameters of the solid nano NiO particles, such as; contact time, initial concentration of lead ions and the dosage of NiO nano catalyst and competitive adsorption behaviors were studied. The results showed that the first-order reaction law fit the reduction of lead ion, also showed good linear relationship with a correlation coefficient (R2 larger than 0.9.

  5. Synthesis and Characterization of Si Oxide Coated Nano Ceria by Hydrolysis, and Hydrothermal Treatment at Low Temperature

    Directory of Open Access Journals (Sweden)

    Kong M.

    2017-06-01

    Full Text Available The purpose of this work was to the application of Si oxide coatings. This study deals with the preparation of ceria (CeO2 nanoparticles coating with SiO2 by water glass and hydrolysis reaction. First, the low temperature hydro-reactions were carried out at 30~100°C. Second, Silicon oxide-coated Nano compounds were obtained by the catalyzing synthesis. CeO2 Nano-powders have been successfully synthesized by means of the hydrothermal method, in a low temperature range of 100~200°C. In order to investigate the structure and morphology of the Nano-powders, scanning electron microscopy (SEM and X-ray diffraction (XRD were employed. The XRD results revealed the amorphous nature of silica nanoparticles. To analyze the quantity and properties of the compounds coated with Si oxide, transmission electron microscopy (TEM in conjunction with electron dispersive spectroscopy was used. Finally, it is suggested that the simple growth process is more favorable mechanism than the solution/aggregation process.

  6. Nano integrated lithium polymer electrolytes based on anodic aluminum oxide (AAO) templates

    Science.gov (United States)

    Bokalawela, Roshan S. P.

    Since their discovery in the 1970s, polymer electrolytes have been actively studied because they have properties important for many device applications. However, even after 40 years, the detailed mechanisms of conductivity in these electrolytes are still not completely understood. Moreover, the conductivity in polymer electrolytes is one of the limiting factors of these devices so that different methods to enhance conductivity are actively being explored. One proposed method of enhancing the conductivity is to confine the polymer electrolyte in the nanoscale, but the study of material properties at the nanoscale is challenging in this area. In this work, we confine poly(ethylene oxide) lithium triflate (PEO:LiTf)(X:1)X=10,30 polymer electrolytes in carefully fabricated nanometer-diameter anodized aluminum oxide (AAO) pore structures. We demonstrate two orders of magnitude higher conductivity in the confined structures versus that of bulk films. Using x-ray characterization we show that this increased conductivity is associated with ordered PEO polymer chains aligned in the template pore direction. The activation energy of the AAO-confined polymer electrolyte is found to be smaller than that of the unconfined melt and about half that of the unconfined solid. This result indicates that not only is the room-temperature confined polymer ordered, but that this order persists at temperatures where the nano-confined polymer electrolyte is expected to be a liquid. The geometric bulk resistances of the electrolytes were obtained by AC-impedance spectra, from which the ionic conductivities were calculated. The Arrhenius plots of temperature dependent ionic conductivities showed that the usual melting temperature of the PEO phase in confined PEO:LiTf(X:1) X=10,30 is suppressed and a single activation energy was evident throughout the temperature range 25--90 °C. Wide-angle x-ray scattering (WAXS) patterns show that the polymer chains in both the pure PEO and PEO:LiTf(10

  7. RE/ZrO{sub 2} (RE = Sm, Eu) composite oxide nano-materials: Synthesis and applications in photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Du, Weimin, E-mail: duweimin75@gmail.com [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); Zhu, Zhaoqiang [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, Henan 450001 (China); Zhang, Xiaofen; Wang, Dacheng; Liu, Donghe [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); Qian, Xuefeng [School of Chemistry and Chemical Technology, Shanghai Jiao Tong University, Shanghai 200240 (China); Du, Jimin, E-mail: djm@aynu.edu.cn [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China)

    2013-10-15

    Graphical abstract: - Highlights: • RE/ZrO{sub 2} (RE = Sm, Eu) nano-materials have been successfully synthesized. • Defect and electron structures determine the absorption properties on visible light. • Nano-sized Zr{sub 0.8}Sm{sub 0.2}O{sub 2−δ} has good visible-light-responsive photocatalytic activities. • In the future, it can be used in wastewater treatment and environmental protection. - Abstract: Zirconia modified by Samarium/Europium, RE/ZrO{sub 2} (RE = Sm, Eu), composite oxide nano-materials have been successfully synthesized by improved sol–gel method. Characterization results show that X-ray diffraction (XRD) peaks of products gradually shift to the lower angle with the increase of rare earth which implies that the lattice distances of RE/ZrO{sub 2} nano-materials are gradually enlarged. Moreover, the molar ratios between zirconium and rare earth are consistent with the chemical formula and both of them are uniformly distributed in samples. Optical properties indicate that defect structures and electron configurations of RE/ZrO{sub 2} (RE = Sm, Eu) with single phase determine their absorption properties on visible light. Photocatalytic experiments indicate Zr{sub 0.8}Sm{sub 0.2}O{sub 2−δ} nano-crystals have excellent visible-light-responsive photocatalytic activities on Methylene blue and Rhodamine B which results from the special defect structure, suitable electronic configuration, and larger specific surface area. It follows that Zr{sub 0.8}Sm{sub 0.2}O{sub 2−δ} nano-crystals are new visible-light-responsive photocatalysts which can be applied in dye wastewater treatment and environmental protection in the future.

  8. Applying graphene oxide nano-film over a polycarbonate nanoporous membrane to monitor E. coli by infrared spectroscopy

    Science.gov (United States)

    Singh, Krishna Pal; Dhek, Neeraj Singh; Nehra, Anuj; Ahlawat, Sweeti; Puri, Anu

    2017-01-01

    Nano-biosensors are excellent monitoring tools for rapid, specific, sensitive, inexpensive, in-field, on-line, and/or real-time detection of pathogens in foods, soil, air, and water samples. A variety of nano-materials (metallic, polymeric, and/or carbon-based) were employed to enhance the efficacy, efficiency, and sensitivity of these nano-biosensors, including graphene-based materials, especially graphene oxide (GO)-based materials. GO bears many oxygen-bearing groups, enabling ligand conjugation at the high density critical for sensitive detection. We have fabricated GO-modified nano-porous polycarbonate track-etched (PCTE) membranes that were conjugated to an Escherichia coli-specific antibody (Ab) and used to detect E. coli. The random distribution of nanopores on the PCTE membrane surface and the bright coating of the GO onto the membrane were confirmed by scanning electron microscope. Anti-E. coli β-gal Abs were conjugated to the GO surface via 1-ethyl-3,3-dimethylaminopropyl carbodiimide hydrochloride-N-hydroxysuccinimide chemistry; antibody coating was confirmed by the presence of a characteristic IR peak near 1600 cm- 1. A non-corresponding Ab (anti-Pseudomonas) was used as a negative control under identical conditions. When E. coli interacted anti-E.coli β-gal with Ab-coated GO-nano-biosensor units, we observed a clear shift in the IR peak from 3373.14 to 3315 cm- 1; in contrast, we did not observe any shift in IR peaks when the GO unit was coated with the non-corresponding Ab (anti-Pseudomonas). Therefore, the detection of E. coli using the described GO-nano-sensor unit is highly specific, is highly selective and can be applied for real-time monitoring of E. coli with a detection limit between 100 μg/mL and 10 μg/mL, similar to existing detection systems.

  9. Application of nano-TiO2/LDPE composite film on photocatalytic oxidation degradation of dichloromethane.

    Science.gov (United States)

    Suwannahong, Kowit; Liengcharernsit, Winai; Sanongraj, Wipada; Kruenate, Jittiporn

    2012-09-01

    This study focused on the photocatalytic destruction of dichloromethane (DCM) in indoor air using the nano-TiO2/LDPE composite film as an economical photocatalyst. The nano-TiO2 was dispersed in a polyethylene matrix to form composite film. The photocatalytic activity of the nano-TiO2/LDPE composite films was evaluated through the degradation of dichloromethane(DCM) under UV-C irradiance at specific wavelength of 254 nm. The percentage of nano-TiO2 contents varied from 0, 5, and 10% (wt cat./wt LDPE composite film). The results derived from the kinetic model revealed that the photocatalytic rates of 5 and 10 wt.% nano-TiO2/ LDPE composite films follow the first order reaction while the rate of the film without TiO2 followed the zero order reaction. At low concentration of DCM, the rate of photocatalytic degradation of the DCM was slower than that at high DCM concentration. The 10 wt.% of TiO2 content of the nano-TiO2/LDPE composite film yielded the highest degradation efficiency of 78%, followed by the removal efficiency of 55% for the 5 wt.% of TiO2 content of the nano-TiO2/LDPE composite film. In contrast with the composite film containing nano-TiO2, the LDPE film without adding nano-TiO2 expressed the degradation efficiency of 28%.

  10. Magnetic separation of encapsulated islet cells labeled with superparamagnetic iron oxide nano particles.

    Science.gov (United States)

    Mettler, Esther; Trenkler, Anja; Feilen, Peter J; Wiegand, Frederik; Fottner, Christian; Ehrhart, Friederike; Zimmermann, Heiko; Hwang, Yong Hwa; Lee, Dong Yun; Fischer, Stefan; Schreiber, Laura M; Weber, Matthias M

    2013-01-01

    Islet cell transplantation is a promising option for the restoration of normal glucose homeostasis in patients with type 1 diabetes. Because graft volume is a crucial issue in islet transplantations for patients with diabetes, we evaluated a new method for increasing functional tissue yield in xenogeneic grafts of encapsulated islets. Islets were labeled with three different superparamagnetic iron oxide nano particles (SPIONs; dextran-coated SPION, siloxane-coated SPION, and heparin-coated SPION). Magnetic separation was performed to separate encapsulated islets from the empty capsules, and cell viability and function were tested. Islets labeled with 1000 μg Fe/ml dextran-coated SPIONs experienced a 69.9% reduction in graft volume, with a 33.2% loss of islet-containing capsules. Islets labeled with 100 μg Fe/ml heparin-coated SPIONs showed a 46.4% reduction in graft volume, with a 4.5% loss of capsules containing islets. No purification could be achieved using siloxane-coated SPIONs due to its toxicity to the primary islets. SPION labeling of islets is useful for transplant purification during islet separation as well as in vivo imaging after transplantation. Furthermore, purification of encapsulated islets can also reduce the volume of the encapsulated islets without impairing their function by removing empty capsules.

  11. Magnetite/graphene oxide nano-composite for enhancement of hydrogen production from gelatinaceous wastewater.

    Science.gov (United States)

    Mostafa, Alsayed; El-Dissouky, Ali; Fawzy, Amal; Farghaly, Ahmed; Peu, Pascal; Dabert, Patrick; Le Roux, Sophie; Tawfik, Ahmed

    2016-09-01

    The effect of substrate to inoculum (So/Xo) ratio and supplementation of magnetite/graphene oxide (MGO) nano-composite material on hydrogen production from gelatinaceous wastewater via dark fermentation process was investigated. Results demonstrated that optimum So/Xo ratio of 1.0gCOD/gVSS achieved maximal hydrogen yield (HY) of 79.2±11.9mL H2/gCOD removed. Supplementation of anaerobes with 100mg/L MGO promoted HY up to 112.4±10.5mL H2/gCOD removed. Moreover, the degradation efficiency of carbohydrates, proteins and lipids was improved to 80.8±7.6, 34.4±2.3 and 31.4±2.2%, respectively. Acetate (HAc) and butyrate (HBu) concentrations increased from 102±6.8 to 125.3±6.3 and from 31.1±1.5 to 48.8±3.5mg/gVSS, respectively. However, propionate (HPr) concentration dropped from 35.9±2.7 to 15±1.3mg/gVSS. Hydrogenase enzyme activity increased 9-folds and the anaerobes elongated from ca. 1.8-2.9 to ca. 2.5-5.1μm with MGO addition. Moreover, Proteobacteria, Firmicutes, Clostridia and Bacilli were detected with the batches supplemented with MGO.

  12. Evaluation of zinc oxide nano-microtetrapods for biomolecule sensing applications

    Science.gov (United States)

    Zhao, Wei; Zhao, Yichen; Karlsson, Mikael; Wang, Qin; Toprak, Muhammet S.

    2015-12-01

    Zinc oxide tetrapods (ZnO-Ts) were synthesized by flame transport synthesis using Zn microparticles. This work herein reports a systematical study on the structural, optical and electrochemical properties of the ZnO-Ts. The morphology of the ZnO-Ts was confirmed by scanning electron microscopy (SEM) as joint structures of four nano-microstructured legs, of which the diameter of each leg is 0.7-2.2 μm in average from the tip to the stem. The ZnO-Ts were dispersed in glucose solution to study the luminescence as well as photocatalytic activity in a mimicked biological environment. The photoluminescence (PL) intensity in the ultraviolet (UV) region quenches with linear dependence to increased glucose concentration up to 4 mM. The ZnO-Ts were also attached with glucose oxidase (GOx) and over coated with a thin film of Nafion to form active layers for electrochemical glucose sensing. The attachment of GOx and coating of Nafion were confirmed by infrared spectroscopy (FT-IR). Furthermore, the current response of the active layers based on ZnO-Ts was investigated by cyclic voltammetry (CV) in various glucose concentrations. Stable current response of glucose was detected with linear dependence to glucose concentration up to 12 mM, which confirms the potential of ZnO-Ts for biomolecule sensing applications.

  13. Thermoluminescence of novel zinc oxide nano phosphors obtained by glycine-based solution combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Orante B, V. R.; Escobar O, F. M.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R., E-mail: victor.orante@polimeros.uson.mx [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico)

    2015-10-15

    Full text: High-dose thermoluminescence dosimetry properties of novel zinc oxide nano phosphors synthesized by a solution combustion method in a glycine-nitrate process are presented for the very first time in this work. Sintered particles with sizes ranging between ∼500 nm and ∼2 μm were obtained by annealing the synthesized Zn O at 900 degrees C during 2 h in air. X-ray diffraction patterns indicate the presence of the Zn O hexagonal phase, without any remaining nitrate peaks observed. Thermoluminescence glow curves of Zn O obtained after being exposed to beta radiation consists of two maxima: one located at ∼ 149 degrees C and another at ∼ 308 degrees C, the latter being the dosimetric component of the curve. The integrated Tl fading displays an asymptotic behaviour for times longer than 16 h between irradiation and the corresponding Tl readout, as well as a linear behaviour of the dose response without saturation in the studied dose interval (from 12.5 up to 400 Gy). Such features place synthesized Zn O as a promising material for high-dose radiation dosimetry applications. (Author)

  14. Synthesis of supported silver nano-spheres on zinc oxide nanorods for visible light photocatalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Saoud, Khaled [Virginia Commonwealth University-Qatar, Doha (Qatar); Alsoubaihi, Rola [Virginia Commonwealth University, Richmond, VA (United States); Bensalah, Nasr [Qatar University, Doha (Qatar); Bora, Tanujjal [Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, P.O. Box 33, Al-Khoudh-123 (Oman); Bertino, Massimo [Virginia Commonwealth University, Richmond, VA (United States); Dutta, Joydeep, E-mail: dutta@squ.edu.om [Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, P.O. Box 33, Al-Khoudh-123 (Oman)

    2015-03-15

    Highlights: • Synthesis of supported Ag NPs on ZnO nanorods using open vessel microwave reactor. • Use of the Ag/ZnO NPs as an efficient visible light photocatalyst. • Complete degradation of methylene blue in 1 h with 0.5 g/L Ag/ZnO NPs. - Abstract: We report the synthesis of silver (Ag) nano-spheres (NS) supported on zinc oxide (ZnO) nanorods through two step mechanism, using open vessel microwave reactor. Direct reduction of ZnO from zinc nitrates was followed by deposition precipitation of the silver on the ZnO nanorods. The supported Ag/ZnO nanoparticles were then characterized by electron microscopy, X-ray diffraction, FTIR, photoluminescence and UV–vis spectroscopy. The visible light photocatalytic activity of Ag/ZnO system was investigated using a test contaminant, methylene blue (MB). Almost complete removal of MB in about 60 min for doses higher than 0.5 g/L of the Ag/ZnO photocatalyst was achieved. This significant improvement in the photocatalytic efficiency of Ag/ZnO photocatalyst under visible light irradiation can be attributed to the presence of Ag nanoparticles on the ZnO nanoparticles which greatly enhances absorption in the visible range of solar spectrum enabled by surface plasmon resonance effect from Ag nanoparticles.

  15. Preparation and characterization of silica coated iron oxide magnetic nano-particles

    Science.gov (United States)

    Li, Ying-Sing; Church, Jeffrey S.; Woodhead, Andrea L.; Moussa, Filsun

    2010-09-01

    Iron oxide magnetic nano-particles have been prepared by precipitation in an aqueous solution of iron(II) and iron(III) chlorides under basic condition. Surface modifications have been carried out by using tetraethoxysilane (TEOS) and mercaptopropyltrimethoxysilane (MPTMS). The uncoated and coated particles have been characterized with transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy, thermal gravimetric analysis (TGA), and infrared (IR) and Raman spectroscopy. The particle sizes as measured from TEM images were found to have mean diameters of 13 nm for the uncoated and about 19 nm for the coated particles. The measured IR spectra of the uncoated and MPTMS coated particles showed the conversion of magnetite to hematite at high temperature. The results obtained from both IR spectroscopy and TGA revealed that the mercaptopropylsilyl group in the MPTMS coated magnetite decomposed at 600 °C and the silica layer of the TEOS coated magnetite was rather stable. Raman spectroscopy has shown the laser heating effect through the conversion of magnetite to maghemite and hematite.

  16. Tooth Discoloration Resulting from a Nano Zinc Oxide-Eugenol Sealer

    Science.gov (United States)

    Zarei, Mina; Javidi, Maryam; Jafari, Marzieh; Gharechahi, Maryam; Javidi, Pedram; Shayani Rad, Maryam

    2017-01-01

    Introduction: A desirable quality of any endodontic sealer is its ability to be tooth color friendly. Therefore the aim of the present study was to evaluate the tooth discoloration potential of a nano zinc oxide-eugenol (NZOE) sealer. Methods and Materials: In order to evaluate tooth discoloration, the pulp chamber of 60 human maxillary central and lateral incisors were filled with one of the sealers, naming AH-26 (resin-based sealer), Pulpdent sealer (ZOE-based) and a NZOE experimental sealer. Color measurements was assessed at the baseline (before placement of sealers) (T0), 24 h (T1) and 72 h (T2) h, 1-week (T3), and 1-month (T4) after the placement of sealers using the Easy Shade spectrophotometer. Data were analyzed in SPSS software using one-way ANOVA, and repeated measured ANOVA. Results: No significant differences were observed when the paired comparison test was performed (P>0.05). Conclusion: The tested NZOE sealer had similar tooth discoloration potential in comparison with AH-26 and ZOE sealer. PMID:28179929

  17. Investigation on Tc tuned nano particles of magnetic oxides for hyperthermia applications.

    Science.gov (United States)

    Giri, Jyotsnendu; Ray, Amlan; Dasgupta, S; Datta, D; Bahadur, D

    2003-01-01

    Superparamagnetic as well as fine ferrimagnetic particles such as Fe3O4, have been extensively used in magnetic field induced localized hyperthermia for the treatment of cancer. The magnetic materials with Curie temperature (Tc) between 42 and 50 degrees C, with sufficient biocompatibility are the best candidates for effective treatment such that during therapy it acts as in vivo temperature control switch and thus over heating could be avoided. Ultrafine particles of substituted ferrite Co(1-a)Zn(a)Fe2O4 and substituted yttrium-iron garnet Y3Fe(5-x)Al(x)O12 have been prepared through microwave refluxing and citrate-gel route respectively. Single-phase compounds were obtained with particle size below 100 nm. In order to make these magnetic nano particles biocompatible, we have attempted to coat these above said composition by alumina. The coating of alumina was done by hydrolysis method. The coating of hydrous aluminium oxide has been done over the magnetic particles by aging the preformed solid particles in the solution of aluminium sulfate and formamide at elevated temperatures. In vitro study is carried out to verify the innocuousness of coated materials towards cells. In vitro biocompatibility study has been carried out by cell culture method for a period of three days using human WBC cell lines. Study of cell counts and SEM images indicates the cells viability/growth. The in vitro experiments show that the coated materials are biocompatible.

  18. Ductility Enhancement of Molybdenum Phase by Nano-sizedd Oxide Dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Bruce Kang

    2008-07-31

    The present research is focused on ductility enhancement of molybdenum (Mo) alloys by adding nano-sized oxide particles to the alloy system. The research approach includes: (1) determination of microscopic mechanisms responsible for the macroscopic ductility enhancement effects through atomistic modeling of the metal-ceramic interface; (2) subsequent computer simulation-aided optimization of composition and nanoparticle size of the dispersion for improved performance; (3) synthesis and characterization of nanoparticle dispersion following the guidance from atomistic computational modeling analyses (e.g., by processing a small sample of Mo alloy for evaluation); and (4) experimental testing of the mechanical properties to determine optimal ductility enhancement.Through atomistic modeling and electronic structure analysis using full-potential linearized muffin-tin orbital (FP-LMTO) techniques, research to date has been performed on a number of selected chromium (Cr) systems containing nitrogen (N) and/or magnesium oxide (MgO) impurities. The emphasis has been on determining the properties of the valence electrons and the characteristics of the chemical bonds they formed. It was found that the brittle/ductile behavior of this transitional metal system is controlled by the relative population of valence charges: bonds formed by s valence electrons yield metallic, ductile behavior, whereas bonds formed by d valence electrons lead to covalent, brittle behavior. The presence of valence bands from impurities also affects the metal bonding, thereby explaining the detrimental and beneficial effects induced by the inclusion of N impurities and MgO dispersions. These understandings are useful for optimizing ductility enhancement effects on the dispersion materials.

  19. Comparative study of pulmonary responses to nano- and submicron-sized ferric oxide in rats.

    Science.gov (United States)

    Zhu, Mo-Tao; Feng, Wei-Yue; Wang, Bing; Wang, Tian-Cheng; Gu, Yi-Qun; Wang, Meng; Wang, Yun; Ouyang, Hong; Zhao, Yu-Liang; Chai, Zhi-Fang

    2008-05-21

    Ferric oxide (Fe(2)O(3)) nanoparticles are of considerable interest for application in nanotechnology related fields. However, as iron being a highly redox-active transition metal, the safety of iron nanomaterials need to be further studied. In this study, the size, dose and time dependent of Fe(2)O(3) nanoparticle on pulmonary and coagulation system have been studied after intratracheal instillation. The Fe(2)O(3) nanoparticles with mean diameters of 22 and 280 nm, respectively, were intratracheally instilled to male Sprague Dawley rats at low (0.8 mg/kgbw) and high (20 mg/kgbw) doses. The toxic effects were monitored in the post-instilled 1, 7 and 30 days. Our results showed that the Fe(2)O(3) nanoparticle exposure could induce oxidative stress in lung. Alveolar macrophage (AM) over-loading of phagocytosed nanoparticle by high dose treatment had occurred, while the non-phagocytosed particles were found entering into alveolar epithelial in day 1 after exposure. Several inflammatory reactions including inflammatory and immune cells increase, clinical pathological changes: follicular hyperplasia, protein effusion, pulmonary capillary vessel hyperaemia and alveolar lipoproteinosis in lung were observed. The sustain burden of particles in AM and epithelium cells has caused lung emphysema and pro-sign of lung fibrosis. At the post-instilled day 30, the typical coagulation parameters, prothrombin time (PT) and activated partial thromboplastin time (APTT) in blood of low dose 22 nm-Fe(2)O(3) treated rats were significantly longer than the controls. We concluded that both of the two-sized Fe(2)O(3) particle intratracheal exposure could induce lung injury. Comparing with the submicron-sized Fe(2)O(3) particle, the nano-sized Fe(2)O(3) particle may increase microvascular permeability and cell lysis in lung epitheliums and disturb blood coagulation parameters significantly.

  20. Some recent results on the correlation of nano-structural and redox properties in ceria-zirconia mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Bernal, S. [Departamento de Ciencia de los Materiales, Ingenieria Metalurgica y Quimica Inorganica, Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, E-11510 Puerto Real (Cadiz) (Spain)], E-mail: serafin.bernal@uca.es; Blanco, G.; Calvino, J.J.; Hernandez, J.C.; Perez-Omil, J.A.; Pintado, J.M.; Yeste, M.P. [Departamento de Ciencia de los Materiales, Ingenieria Metalurgica y Quimica Inorganica, Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, E-11510 Puerto Real (Cadiz) (Spain)

    2008-02-28

    Some recent results on the redox behaviour of thermally aged ceria-zirconia mixed oxides with Ce/Zr molar ratios typically ranging from 50/50 to 70/30 are briefly reviewed. In accordance with them, a tentative model allowing us to correlate ageing conditions, surface and bulk nano-structural properties of the oxides, and changes occurred in their redox behaviour is proposed. As revealed by the analysis of appropriate chemical studies and the nano-structural information provided with High Resolution Transmission (HREM) and High Angle Annular Dark Field-Scanning Transmission (HAADF-STEM) electron microscopies, the presence/absence of a pyrochlore-related {kappa}-phase in the aged oxides plays a key role in determining their redox response. In the low-temperature region (T{sub red} {<=} 773 K), the enhanced reducibility exhibited by the oxide resulting from a high-temperature reduction/mild re-oxidation ageing cycle (SR-MO sample) is interpreted as due to kinetic reasons, the occurrence of the {kappa}-like phase in its surface being responsible for a faster H{sub 2} chemisorption, the rate controlling step of the overall reduction process. By contrast, in the high-temperature range (T{sub red} {>=} 973 K), the observed differences of reducibility would have a thermodynamic origin, which may be correlated with the total amount of {kappa}-like phase present in the aged sample.

  1. Surface enrichment of Pt in stable Pt-Ir nano-alloy particles on MgAl 2 O 4 spinel in oxidizing atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wei-Zhen; Nie, Lei; Cheng, Yingwen; Kovarik, Libor; Liu, Jun; Wang, Yong

    2017-04-01

    With the capability of MgAl2O4 spinel {111} nano-facets in stabilizing small Rh, Ir and Pt particles, bimetallic Ir-Pt catalysts on the same support were investigated, aiming at further lowering the catalyst cost by substituting expensive Pt with cheaper Ir in the bulk. Small Pt-Ir nano-alloy particles (< 2nm) were successfully stabilized on the spinel {111} nano-facets as expected. Interestingly, methanol oxidative dehydrogenation (ODH) rate on the surface Pt atoms increases with oxidizing aging but decreases upon reducing treatment, where Ir is almost inactive under the same reaction conditions. Up to three times enhancement in Pt exposure was achieved when the sample was oxidized at 800 °C in air for 1 week and subsequently reduced by H2 for 2 h, demonstrating successful surface enrichment of Pt on Pt-Ir nano-alloy particles. A dynamic stabilization mechanism involving wetting\

  2. Fabrication of a Ni nano-imprint stamp for an anti-reflective layer using an anodic aluminum oxide template.

    Science.gov (United States)

    Park, Eun-Mi; Lim, Seung-Kyu; Ra, Senug-Hyun; Suh, Su-Jung

    2013-11-01

    Aluminum anodizing can alter pore diameter, density distribution, periodicity and layer thickness in a controlled way. Because of this property, porous type anodic aluminum oxide (AAO) was used as a template for nano-structure fabrication. The alumina layer generated at a constant voltage increased the pore size from 120 nm to 205 nm according to an increasing process time from 60 min to 150 min. The resulting fabricated AAO templates had pore diameters at or less than 200 nm. Ni was sputtered as a conductive layer onto this AAO template and electroplated using DC and pulse power. Comparing these Ni stamps, those generated from electroplating using on/reverse/off pulsing had an ordered pillar array and maintained the AAO template morphology. This stamp was used for nano-imprinting on UV curable resin coated glass wafer. Surface observations via electron microscopy showed that the nano-imprinted patterned had the same shape as the AAO template. A soft mold was subsequently fabricated and nano-imprinted to form a moth-eye structure on the glass wafer. An analysis of the substrate transmittance using UV-VIS/NIR spectroscopy showed that the transmittance of the substrate with the moth-eye structure was 5% greater that the non-patterned substrate.

  3. Treatment and Kinetic of Synthetic Wastewater Containing β-Naphthol by Nano Titanium Oxide Coated on Activated Carbon

    Directory of Open Access Journals (Sweden)

    H Ijad panah

    2012-03-01

    Full Text Available Background and Objectives: Many industrial effluent plants contain amounts of hard biodegradable compounds such as β-naphthol which can be removed by conventional treatment systems. The objective of this research is to treat wastewater containing naphthalene by nano titanium oxide coated on activated carbon. Materials and Methods: Photocatalytic experiments were carried out for different concentrations of β-naphthol using time and pH as dependent factors. Nano TiO2 coated on activated carbone in one liter batch reactor and the resultants compounds concentration were measured in a photocatalytic reactor  with UV-C of 12 Watt. Results: The experimental results indicated that UV/ nano TiO2 coated on activated carbone removed 92% of β-naphthol with concentrations of 100 mg/L within an overall elapsed time of three hours. β-naphthol total removal with concenteration of 25 mg/L was observed in two hours.Conclusions: UV/ nano TiO2 process is very fast and effective method for removal of β-naphthol and  pH 11 was indicated as the optimum pH.

  4. The way to cover prediction for cytotoxicity for all existing nano-sized metal oxides by using neural network method.

    Science.gov (United States)

    Fjodorova, Natalja; Novic, Marjana; Gajewicz, Agnieszka; Rasulev, Bakhtiyor

    2017-05-01

    The regulatory agencies should fulfil the data gap in toxicity for new chemicals including nano-sized compounds, like metal oxides nanoparticles (MeOx NPs) according to the registration, evaluation, authorisation and restriction of chemicals (REACH) legislation policy. This study demonstrates the perspective capability of neural network models for prediction of cytotoxicity of MeOx NPs to bacteria Escherichia coli (E. coli) for the widest range of metal oxides extracted from Periodic table. The counter propagation artificial neural network (CP ANN) models for prediction of cytotoxicity of MeOx NPs for data sets of 17, 36 and 72 metal oxides were employed in the study. The cytotoxicity of studied metal oxide NPs was correlated with (i) χ-metal electronegativity (EN) by Pauling scale and composition of metal oxides characterised by (ii) number of metal atoms in oxide, (iii) number of oxygen atoms in oxide and (iv) charge of metal cation in oxide. The paper describes the models in context of five OECD principles of validation models accepted for regulatory use. The recommendations were done for the minimal number of cytotoxicity tests needs for evaluation of the large set of MeOx with different oxidation states. The methodology is expected to be useful for potential hazard assessment of MeOx NPs and prioritisation for further testing and risk assessment.

  5. Evaluation of nano-specific toxicity of zinc oxide, copper oxide, and silver nanoparticles through toxic ratio

    Science.gov (United States)

    Zhang, Weicheng; Liu, Xiawei; Bao, Shaopan; Xiao, Bangding; Fang, Tao

    2016-12-01

    For safety and environmental risk assessments of nanomaterials (NMs) and to provide essential toxicity data, nano-specific toxicities, or excess toxicities, of ZnO, CuO, and Ag nanoparticles (NPs) (20, 20, and 30 nm, respectively) to Escherichia coli and Saccharomyces cerevisiae in short-term (6 h) and long-term (48 h) bioassays were quantified based on a toxic ratio. ZnO NPs exhibited no nano-specific toxicities, reflecting similar toxicities as ZnO bulk particles (BPs) (as well as zinc salt). However, CuO and Ag NPs yielded distinctly nano-specific toxicities when compared with their BPs. According to their nano-specific toxicities, the capability of these NPs in eliciting hazardous effects on humans and the environment was as follows: CuO > Ag > ZnO NPs. Moreover, long-term bioassays were more sensitive to nano-specific toxicity than short-term bioassays. Overall, nano-specific toxicity is a meaningful measurement to evaluate the environmental risk of NPs. The log T e particle value is a useful parameter for quantifying NP nano-specific toxicity and enabling comparisons of international toxicological data. Furthermore, this value could be used to determine the environmental risk of NPs.

  6. Optimal nano-descriptors as translators of eclectic data into prediction of the cell membrane damage by means of nano metal-oxides.

    Science.gov (United States)

    Toropova, Alla P; Toropov, Andrey A; Benfenati, Emilio; Korenstein, Rafi; Leszczynska, Danuta; Leszczynski, Jerzy

    2015-01-01

    Systematization of knowledge on nanomaterials has become a necessity with the fast growth of applications of these species. Building up predictive models that describe properties (both beneficial and hazardous) of nanomaterials is vital for computational sciences. Classic quantitative structure-property/activity relationships (QSPR/QSAR) are not suitable for investigating nanomaterials because of the complexity of their molecular architecture. However, some characteristics such as size, concentration, and exposure time can influence endpoints (beneficial or hazardous) related to nanoparticles and they can therefore be involved in building a model. Application of the optimal descriptors calculated with the so-called correlation weights of various concentrations and different exposure times are suggested in order to build up a predictive model for cell membrane damage caused by a series of nano metal-oxides. The numerical data on correlation weights are calculated by the Monte Carlo method. The obtained results are in good agreement with the experimental data.

  7. Direct electrochemistry and electrocatalytic activity of catalase immobilized onto electrodeposited nano-scale islands of nickel oxide.

    Science.gov (United States)

    Salimi, Abdollah; Sharifi, Ensiyeh; Noorbakhsh, Abdollah; Soltanian, Saied

    2007-02-01

    Cyclic voltammetry was used for simultaneous formation and immobilization of nickel oxide nano-scale islands and catalase on glassy carbon electrode. Electrodeposited nickel oxide may be a promising material for enzyme immobilization owing to its high biocompatibility and large surface. The catalase films assembled on nickel oxide exhibited a pair of well defined, stable and nearly reversible CV peaks at about -0.05 V vs. SCE at pH 7, characteristic of the heme Fe (III)/Fe (II) redox couple. The formal potential of catalase in nickel oxide film were linearly varied in the range 1-12 with slope of 58.426 mV/pH, indicating that the electron transfer is accompanied by single proton transportation. The electron transfer between catalase and electrode surface, (k(s)) of 3.7(+/-0.1) s(-1) was greatly facilitated in the microenvironment of nickel oxide film. The electrocatalytic reduction of hydrogen peroxide at glassy carbon electrode modified with nickel oxide nano-scale islands and catalase enzyme has been studied. The embedded catalase in NiO nanoparticles showed excellent electrocatalytic activity toward hydrogen peroxide reduction. Also the modified rotating disk electrode shows good analytical performance for amperometric determination of hydrogen peroxide. The resultant catalase/nickel oxide modified glassy carbon electrodes exhibited fast amperometric response (within 2 s) to hydrogen peroxide reduction (with a linear range from 1 microM to 1 mM), excellent stability, long term life and good reproducibility. The apparent Michaelis-Menten constant is calculated to be 0.96(+/-0.05)mM, which shows a large catalytic activity of catalase in the nickel oxide film toward hydrogen peroxide. The excellent electrochemical reversibility of redox couple, high stability, technical simplicity, lake of need for mediators and short preparations times are advantages of this electrode. Finally the activity of biosensor for nitrite reduction was also investigated.

  8. Ceria-Based Mixed Oxide Supported Nano-Gold as an Efficient and Durable Heterogeneous Catalyst for Oxidative Dehydrogenation of Amines to Imines Using Molecular Oxygen

    Directory of Open Access Journals (Sweden)

    Bashir Ahmad Dar

    2012-06-01

    Full Text Available The present work is intended to determine the catalytic activity of Mixed Oxide supported gold for aerobic oxidative dehydrogenation of amines to imines using Ceria as a main constituent of the each support. The model catalysts Au/CeO2:TiO2 Au/CeO2:SiO2, Au/CeO2:ZrO2 and Au/CeO2:Al2Os were prepared by deposition co-precipitation method and deposition of gold was determined by EDEX analysis. The supported nano-gold catalyzes the dehydrogenation of secondary amines to imines without loss of activity. On recycling good amount of product yield is obtained. Oxidation of secondary amines to imines is carried at 100˚C and almost 90 % conversion was obtained with >99% selectivity. © 2012 BCREC UNDIP. All rights reservedReceived: 26th December 2011; Revised: 7th June 2012; Accepted: 13rd June 2012[How to Cite: B.A. Dar, M. Sharma, B. Singh. (2012. Ceria-Based Mixed Oxide Supported Nano-Gold as an Efficient and Durable Heterogeneous Catalyst for Oxidative Dehydrogenation of Amines to Imines Using Molecular Oxygen. Bulletin of Chemical Reaction Engineering & Catalysis, 7(1: 79-84.  doi:10.9767/bcrec.7.1.1257.79-84][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.1.1257.79-84 ] | View in 

  9. Markers of lipid oxidative damage among office workers exposed intermittently to air pollutants including nanoTiO2 particles.

    Science.gov (United States)

    Pelclova, Daniela; Zdimal, Vladimir; Kacer, Petr; Komarc, Martin; Fenclova, Zdenka; Vlckova, Stepanka; Zikova, Nadezda; Schwarz, Jaroslav; Makes, Otakar; Navratil, Tomas; Zakharov, Sergey; Bello, Dhimiter

    2017-03-01

    Nanoscale titanium dioxide (nanoTiO2) is a commercially important nanomaterial used in numerous applications. Experimental studies with nanotitania have documented lung injury and inflammation, oxidative stress, and genotoxicity. Production workers in TiO2 manufacturing with a high proportion of nanoparticles and a mixture of other air pollutants, such as gases and organic aerosols, had increased markers of oxidative stress, including DNA and protein damage, as well as lipid peroxidation in their exhaled breath condensate (EBC) compared to unexposed controls. Office workers were observed to get intermittent exposures to nanoTiO2 during their process monitoring. The aim of this study was to investigate the impact of such short-term exposures on the markers of health effects in office workers relative to production workers from the same factory. Twenty-two office employees were examined. They were occupationally exposed to (nano)TiO2 aerosol during their daily visits of the production area for an average of 14±9 min/day. Median particle number concentration in office workers while in the production area was 2.32×104/cm3. About 80% of the particles were meaning of their physiological values in the context of chronic disease development and damage-repair kinetics.

  10. Neurotoxicity of low-dose repeatedly intranasal instillation of nano- and submicron-sized ferric oxide particles in mice

    Science.gov (United States)

    Wang, Bing; Feng, Weiyue; Zhu, Motao; Wang, Yun; Wang, Meng; Gu, Yiqun; Ouyang, Hong; Wang, Huajian; Li, Ming; Zhao, Yuliang; Chai, Zhifang; Wang, Haifang

    2009-01-01

    Olfactory tract has been demonstrated to be an important portal for inhaled solid nanoparticle transportation into the central nervous system (CNS). We have previously demonstrated that intranasally instilled Fe2O3 nanoparticles could transport into the CNS via olfactory pathway. In this study, we investigated the neurotoxicity and size effect of repeatedly low-dose (130 μg) intranasal exposure of nano- and submicron-sized Fe2O3 particles (21 nm and 280 nm) to mice. The biomarkers of oxidative stress, activity of nitric oxide synthases and release of monoamine neurotransmitter in the brain were studied. Our results showed that significant oxidative stress was induced by the two sizes of Fe2O3 particles. The activities of GSH-Px, Cu,Zn-SOD, and cNOS significantly elevated and the total GSH and GSH/GSSG ratio significantly decreased in the olfactory bulb and hippocampus after the nano- and submicron-sized Fe2O3 particle treatment ( p < 0.05). The nano-sized Fe2O3 generally induced greater alteration and more significant dose-effect response than the submicron-sized particle did. Some slight perturbation of monoamine neurotransmitters were found in the hippocampus after exposure to the two sizes of Fe2O3 particle. The TEM image showed that some ultrastructural alterations in nerve cells, including neurodendron degeneration, membranous structure disruption and lysosome increase in the olfactory bulb, slight dilation in the rough endoplasmic reticulum and lysosome increase in the hippocampus were induced by the nano-sized Fe2O3 treatment. In contrast, in the submicron-sized Fe2O3 treated mice, slightly swollen mitochondria and some vacuoles were observed in the olfactory bulb and hippocampus, respectively. These results indicate that intranasal exposure of Fe2O3 nanoparticles could induce more severe oxidative stress and nerve cell damage in the brain than the larger particle did. This is the first study to compare the neurotoxicity of nano- and submicron-sized Fe2O3

  11. Neurotoxicity of low-dose repeatedly intranasal instillation of nano- and submicron-sized ferric oxide particles in mice

    Energy Technology Data Exchange (ETDEWEB)

    Wang Bing; Feng Weiyue, E-mail: fengwy@mail.ihep.ac.cn; Zhu Motao; Wang Yun; Wang Meng [Chinese Academy of Sciences, Laboratory for Bio-Environmental Effects of Nanomaterials and Nanosafety and Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics (China); Gu Yiqun [Maternity Hospital of Haidian District (China); Ouyang Hong; Wang Huajian; Li Ming; Zhao Yuliang, E-mail: zhaoyuliang@mail.ihep.ac.cn; Chai Zhifang [Chinese Academy of Sciences, Laboratory for Bio-Environmental Effects of Nanomaterials and Nanosafety and Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics (China); Wang Haifang [Peking University, College of Chemistry and Molecular Engineering (China)

    2009-01-15

    Olfactory tract has been demonstrated to be an important portal for inhaled solid nanoparticle transportation into the central nervous system (CNS). We have previously demonstrated that intranasally instilled Fe{sub 2}O{sub 3} nanoparticles could transport into the CNS via olfactory pathway. In this study, we investigated the neurotoxicity and size effect of repeatedly low-dose (130 {mu}g) intranasal exposure of nano- and submicron-sized Fe{sub 2}O{sub 3} particles (21 nm and 280 nm) to mice. The biomarkers of oxidative stress, activity of nitric oxide synthases and release of monoamine neurotransmitter in the brain were studied. Our results showed that significant oxidative stress was induced by the two sizes of Fe{sub 2}O{sub 3} particles. The activities of GSH-Px, Cu,Zn-SOD, and cNOS significantly elevated and the total GSH and GSH/GSSG ratio significantly decreased in the olfactory bulb and hippocampus after the nano- and submicron-sized Fe{sub 2}O{sub 3} particle treatment (p < 0.05). The nano-sized Fe{sub 2}O{sub 3} generally induced greater alteration and more significant dose-effect response than the submicron-sized particle did. Some slight perturbation of monoamine neurotransmitters were found in the hippocampus after exposure to the two sizes of Fe{sub 2}O{sub 3} particle. The TEM image showed that some ultrastructural alterations in nerve cells, including neurodendron degeneration, membranous structure disruption and lysosome increase in the olfactory bulb, slight dilation in the rough endoplasmic reticulum and lysosome increase in the hippocampus were induced by the nano-sized Fe{sub 2}O{sub 3} treatment. In contrast, in the submicron-sized Fe{sub 2}O{sub 3} treated mice, slightly swollen mitochondria and some vacuoles were observed in the olfactory bulb and hippocampus, respectively. These results indicate that intranasal exposure of Fe{sub 2}O{sub 3} nanoparticles could induce more severe oxidative stress and nerve cell damage in the brain than the

  12. Effect of Iron Oxides (Ordinary and Nano and Municipal Solid Waste Compost (MSWC Coated Sulfur on Wheat (Triticum aestivum L. Plant Iron Concentration and Growth

    Directory of Open Access Journals (Sweden)

    S Mazaherinia

    2011-02-01

    Full Text Available Abstract A greenhouse study was conducted to compare the effects of ordinary iron oxide (0.02-0.06 mm and nano iron oxide (25-250 nm and five levels of both iron oxides (0, 0.05, 0.1, 0.5, and 1.0 %w/w and two levels of sulfurous granular compost (MSW (0 and 2% w/w on plant height, spike length, grain weight per spike, total plant dry matter weight and thousands grain weight of wheat. The experimental factors were combined in factorial arrangement in a completely randomized design with 3 replications. Results showed that nano iron oxide was superior over ordinary iron oxide in all parameters studied. Fe concentration, spike length, plant height, grain weight per spike, total plant dry weight and thousands grain weight showed increasing trend per increase in both of iron oxides levels. Also, all parameters studied in sulfurous granular compost (MSW treatment were superior over granular compost without sulfurous (MSW. This increase in all parameters were significantly higher when urban solid waste compost coated with sulfur coupled with nano iron oxide compared to urban sulfurous granular compost (MSW along with ordinary iron oxide. Keywords: Sulfurous granular compost (MSW, Nano and ordinary iron oxides, Wheat

  13. Effects of Treated Nano-Lanthanum Oxide on the Mechanical and Tribological Properties of PTFE Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    Wang Huaiyuan; Feng Xin; Shi Yijun; Lu Xiaohua

    2007-01-01

    The surface of nano-La2O3 was modified. Effects of various amount of treated nano-La2O3 on the mechanical and tribological properties of PTFE were investigated. Mechanisms that contribute to the properties of PTFE composites are also studied. Results indicate that treated nano-La2O3 can increase the mechanical and tribological properties of PTFE simultaneously. With 1wt.% of treated nano-La2O33, the rigidity, tensile strength, notched impact and wear resistance of PTFE nanocomposites were increased by 25.1%,14.1%,20.3% and 36.7% respectively over pure PTFE. The degradation temperature of PTFE was improved by 14℃ by adding only 5% nano-La2O3. The wear resistance reached the highest value when the composite contained 10% treated nano-La2O3, which is about 110 times higher than pure PTFE. Furthermore, treated nano-La2O3 strengthened the bonding between the transfer film and the counterpart surface. A coherent and smooth transfer film on the counterpart surface of PTFE composites can be observed, while pure PTFE can not do.

  14. Characterization of Nano-scale Aluminum Oxide Transport Through Porous Media

    Science.gov (United States)

    Norwood, Sasha Norien

    Land application of biosolids has become common practice in the United States as an alternative to industrial fertilizers. Although nutrient rich, biosolids have been found to contain high concentrations of unregulated and/or unrecognized emerging contaminants (e.g., pharmaceuticals, personal care products) while containing a significant fraction of inorganic nano-scale colloidal materials such as oxides of iron, titanium, and aluminum. Given their reactivity and small size, there are many questions concerning the potential migration of these nano-sized colloidal materials through the soil column and into our surface and groundwater bodies. Transport of emerging pollutants of concern through the soil column, at minimum, is impacted by colloidal properties (e.g., chemical composition, shape, aggregation kinetics), solution chemistry (e.g., pH, ionic strength, natural organic matter), and water flow velocity. The purpose of this current research was to characterize the long-term transport behavior of aluminum oxide nanoparticles (Al 2O3) through a natural porous media with changes in pH, aqueous-phase concentration, pore-water velocity and electrolyte valence. Additionally, deposition rates during the initial stages of deposition were compared to several models developed based on colloid filtration theory and DLVO stability theory. Benchtop column laboratory experiments showed that, under environmentally relevant groundwater conditions, Al2O3 nanoparticles are mobile through saturated porous media. Mobility increased under conditions in which the nanoparticles and porous media were of like charge (pH 9). Changes in linear pore water velocity, under these same high pH conditions, showed similar transport behavior with little mass retained in the system. Deposition is believed to be kinetically controlled at pH 9, as evidenced by the slightly earlier breakthrough as flow rate increased and was further supported by observed concentration effects on the arrival wave

  15. Synthesis, characterization, antimicrobial activity and mechanism of a novel hydroxyapatite whisker/nano zinc oxide biomaterial.

    Science.gov (United States)

    Yu, Jian; Zhang, Wenyun; Li, Yang; Wang, Gang; Yang, Lidou; Jin, Jianfeng; Chen, Qinghua; Huang, Minghua

    2014-12-23

    Postoperative infections remain a risk factor that leads to failures in oral and maxillofacial artificial bone transplantation. This study aimed to synthesize and evaluate a novel hydroxyapatite whisker (HAPw) / nano zinc oxide (n-ZnO) antimicrobial bone restorative biomaterial. A scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD) were employed to characterize and analyze the material. Antibacterial capabilities against Staphylococcus aureus, Escherichia coli, Candida albicans and Streptococcus mutans were determined by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), and kinetic growth inhibition assays were performed under darkness and simulated solar irradiation. The mode of antibiotic action was observed by transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). The MIC and MBC were 0.078-1.250 mg ml(-1) and 0.156-2.500 mg ml(-1), respectively. The inhibitory function on the growth of the microorganisms was achieved even under darkness, with gram-positive bacteria found to be more sensitive than gram-negative, and enhanced antimicrobial activity was exhibited under simulated solar excitation compared to darkness. TEM and CLSM images revealed a certain level of bacterial cell membrane destruction after treatment with 1 mg ml(-1) of the material for 12 h, causing the leakage of intracellular contents and bacteria death. These results suggest favorable antibiotic properties and a probable mechanism of the biomaterial for the first time, and further studies are needed to determine its potential application as a postoperative anti-inflammation method in bone transplantation.

  16. Evaluating the Microshear Bond Strength and Microleakage of Flowable Composites Containing Zinc Oxide Nano-particles

    Science.gov (United States)

    Teymoornezhad, Koorosh; Alaghehmand, Homayoun; Daryakenari, Ghazaleh; Khafri, Soraya; Tabari, Mitra

    2016-01-01

    Introduction Preventive resin restorations (PRR) are the conservative choice for the most common carious lesions in children. Thus, new age flowable resin composites with higher filler content are readily used. The aim of this study was to evaluate the microshear bond strength and microleakage of two flowable resin composites containing different percentages of nano zinc oxide (NZnO) particles, which have proven to have antimicrobial properties. Methods This experimental in-vitro study was carried out in the Dental Material Research Center of Babol University of Medical Sciences in 2015. One nanohybrid and one nanofill flowable resin composite were chosen and modified with the incorporation of 1% and 3% Wt NZnO particles. Six groups (n=10, 0%, 1%, and 3%) of resin composite sticks on dental enamel (2×2mm) were prepared to be placed in the microtensile tester. The microshear bond strength magnitude (MPa) was recorded at the point of failure. A class I box (3×0.8×1 mm) was prepared on 60 premolars and filled using the resin composites (6 groups, n=10). The specimens were immersed in a 5% basic fuschin solution and sectioned bucco-lingually to view the microleakage using a stereomicroscope. One-way ANOVA and Tukey tests for microshear and Wilcoxon and Kruskal–Wallis tests for microleakage were used to analyze the data in the IBM SPSS Statistics version 22 software. Results The bond strength of the 3% clearfill group significantly decreased while no significant change occurred in the bond strength in other groups. The Z-350 group had significantly lower microleakage as nanoparticles increased. No significant difference was observed in the clearfill group. Conclusion Up to 3% Wt incorporation of NZnO particles will not diversely alter the bond strength, but it will be beneficial in providing antimicrobial effects with lower microleakage rates. PMID:28070263

  17. Synthesis and characterization of barium titanate, doped with europium and neodymium; Sintese e caracterizacao de titanato de bario, dopados com europio e neodimio

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Fernanda L.C.; Cabral, Alciney M.; Silva, Ademir O.; Oliveiro, Joao B.L., E-mail: nanda_louise@yahoo.com.br [Universidade Federal do Rio Grande do Norte (UFRN), Natal (Brazil). Instituto de Quimica

    2013-07-01

    This work aims at synthesize and characterize mixed oxides in Barium Titanium matrix in doping with Neodymium and Europium analyzing thermogravimetric curves, characteristic bands at infrared region of the polymer complex, which are intermediates to mixed oxides, and identify the formation thereof, and the crystallinity using XRD analysis.

  18. Application of nano-encapsulated olive leaf extract in controlling the oxidative stability of soybean oil.

    Science.gov (United States)

    Mohammadi, Adeleh; Jafari, Seid Mahdi; Esfanjani, Afshin Faridi; Akhavan, Sahar

    2016-01-01

    Our objective was to evaluate the antioxidant activity of olive leave extract (OLE) encapsulated by nano-emulsions in soybean oil. The average droplet size one day after production was 6.16 nm for primary W/O nano-emulsion and, 675 nm and 1443 nm for multiple emulsions stabilized by WPC alone and complex of WPC-pectin, respectively. The antioxidant activity of these emulsions containing three concentrations of 100, 200 and 300 mg OLE during storage was evaluated in soybean oil by peroxide value, TBA value and rancimat thermal stability test and was compared with blank (non-encapsulated) OLE and synthetic TBHQ antioxidant. Nano-encapsulated OLE was capable of controlling peroxide value better than unencapsulated OLE. But because of blocking phenolic compounds within dispersed emulsions droplets, thermal stability of encapsulated OLE was lower. To summarize, with increased solubility and controlled release of olive leaf phenolic compounds through their nano-encapsulation, a higher antioxidant activity was achieved.

  19. Development of nano indium tin oxide (ITO) grains by alkaline hydrolysis of In(III) and Sn(IV) salts

    Indian Academy of Sciences (India)

    Nimai Chand Pramanik; Prasanta Kumar Biswas

    2002-11-01

    Indium tin oxide (ITO) nano powders of different compositions (In : Sn = 90 : 10, 70 : 30 and 50 : 50) were prepared by heat treatment (300–450°C) of mixed hydroxides of In(III) and Sn(IV). The hydroxides were obtained by the reaction of aq. NH3 with mixed aq. solutions of In(NO3)3 and SnCl4. FTIR and TG/DTA studies revealed that powders existed as In(OH)3 H2O−SnO3H2 H2O in the solid state and then they transformed to In2O3–SnO2 via some metastable intermediates after 300°C. Cubic phase of In2O3 was identified by XRD for the oxides up to 30% of Sn. Particle size measurements of the solid dispersed in acetone and SEM study for microstructure showed that the oxides were in the nano range (55–75 nm) whereas the size range determined from Debye–Scherrer equation were 11–24 nm.

  20. Twenty-eight-day repeated inhalation toxicity study of nano-sized lanthanum oxide in male sprague-dawley rats.

    Science.gov (United States)

    Shin, Seo-Ho; Lim, Cheol-Hong; Kim, Yong-Soon; Lee, Yong-Hoon; Kim, Sung-Hwan; Kim, Jong-Choon

    2017-04-01

    Although the use of lanthanum has increased in field of high-tech industry worldwide, potential adverse effects to human health and to the environment are largely unknown. The present study aimed to investigate the potential toxicity of nano-sized lanthanum oxide (La2 O3 ) following repeated inhalation exposure in male Sprague-Dawley rats. Male rats were exposed nose-only to nano-sized La2 O3 for 28 days (5 days/week) at doses of 0, 0.5, 2.5, and 10 mg/m(3) . In the experimental period, we evaluated treatment-related changes including clinical signs, body weight, hematology, serum biochemistry, necropsy findings, organ weight, and histopathology findings. We also analyzed lanthanum distribution in the major organs and in the blood, bronchoalveolar lavage fluids (BALF), and oxidative stress in lung tissues. Lanthanum level was highest in lung tissues and showed a dose-dependent relation. Alveolar proteinosis was observed in all treatment groups and was accompanied by an increase in lung weight; moreover, lung inflammation was observed in the 2.5 mg/m(3) and higher dose groups and was accompanied by an increase in white blood cells. In the BALF, total cell counts including macrophages and neutrophils, lactate dehydrogenase, albumin, nitric oxide, and tumor necrosis factor-alpha increased significantly in all treatment groups. Furthermore, these changes tended to deteriorate in the 10 mg/m(3) group at the end of the recovery period. In the present experimental conditions, we found that the lowest-observed-adverse-effect level of nano-sized La2 O3 was 0.5 mg/m(3) in male rats, and the target organ was the lung. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1226-1240, 2017. © 2016 Wiley Periodicals, Inc.

  1. Novel processing of bioglass ceramics from silicone resins containing micro- and nano-sized oxide particle fillers.

    Science.gov (United States)

    Fiocco, L; Bernardo, E; Colombo, P; Cacciotti, I; Bianco, A; Bellucci, D; Sola, A; Cannillo, V

    2014-08-01

    Highly porous scaffolds with composition similar to those of 45S5 and 58S bioglasses were successfully produced by an innovative processing method based on preceramic polymers containing micro- and nano-sized fillers. Silica from the decomposition of the silicone resins reacted with the oxides deriving from the fillers, yielding glass ceramic components after heating at 1000°C. Despite the limited mechanical strength, the obtained samples possessed suitable porous architecture and promising biocompatibility and bioactivity characteristics, as testified by preliminary in vitro tests.

  2. Investigation of superhydrophilic mechanism of titania nano layer thin film—Silica and indium oxide dopant effect

    Indian Academy of Sciences (India)

    Akbar Eshaghi; Ameneh Eshaghi

    2012-04-01

    In this paper, TiO2–SiO2–In2O3 nano layer thin films were deposited on glass substrate using sol–gel dip coating method. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and water contact angle measurements were used to evaluate chemical structure, surface composition, hydroxyl group contents and superhydrophilicity of titania films. FTIR result indicated that Si–O–Si, Si–O–Ti and Ti–O–Ti bands formed in TiO2–SiO2–In2O3 sample. According to XPS, the hydroxyl content for TiO2, TiO2–SiO2 and TiO2–SiO2–In2O3 films was calculated as 11.6, 17.1 and 20.7%, respectively. The water contact angle measurements indicated that silica and indium oxide dopant improved the superhydrophilicity of titania nano film surface especially in a dark place. The enhanced superhydrophilicity can be related to the generation of surface acidity on the titania nano film surfaces. In the present state, superhydrophilicity is induced by the simultaneous presence of both Lewis and Bronsted sites.

  3. Applying graphene oxide nano-film over a polycarbonate nanoporous membrane to monitor E. coli by infrared spectroscopy.

    Science.gov (United States)

    Singh, Krishna Pal; Dhek, Neeraj Singh; Nehra, Anuj; Ahlawat, Sweeti; Puri, Anu

    2017-01-05

    Nano-biosensors are excellent monitoring tools for rapid, specific, sensitive, inexpensive, in-field, on-line, and/or real-time detection of pathogens in foods, soil, air, and water samples. A variety of nano-materials (metallic, polymeric, and/or carbon-based) were employed to enhance the efficacy, efficiency, and sensitivity of these nano-biosensors, including graphene-based materials, especially graphene oxide (GO)-based materials. GO bears many oxygen-bearing groups, enabling ligand conjugation at the high density critical for sensitive detection. We have fabricated GO-modified nano-porous polycarbonate track-etched (PCTE) membranes that were conjugated to an Escherichia coli-specific antibody (Ab) and used to detect E. coli. The random distribution of nanopores on the PCTE membrane surface and the bright coating of the GO onto the membrane were confirmed by scanning electron microscope. Anti-E. coli β-gal Abs were conjugated to the GO surface via 1-ethyl-3,3-dimethylaminopropyl carbodiimide hydrochloride-N-hydroxysuccinimide chemistry; antibody coating was confirmed by the presence of a characteristic IR peak near 1600cm(-1). A non-corresponding Ab (anti-Pseudomonas) was used as a negative control under identical conditions. When E. coli interacted anti-E.coli β-gal with Ab-coated GO-nano-biosensor units, we observed a clear shift in the IR peak from 3373.14 to 3315cm(-1); in contrast, we did not observe any shift in IR peaks when the GO unit was coated with the non-corresponding Ab (anti-Pseudomonas). Therefore, the detection of E. coli using the described GO-nano-sensor unit is highly specific, is highly selective and can be applied for real-time monitoring of E. coli with a detection limit between 100μg/mL and 10μg/mL, similar to existing detection systems. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Electric field effect on the Néel temperature of cobalt oxide formed at an alumina nano-oxide layer

    Science.gov (United States)

    Al-Mahdawi, Muftah; Sahashi, Masashi

    2017-02-01

    The electric control of surface magnetism is important for spintronic applications. Due to the screening of electric field by conduction electrons in metals, an electric field can be applied only at a surface layer. However, the electric field can be applied on metallic contacts smaller than the electron’s mean free path. We report on the electric modulation of the phase-transition temperature of CoO that is present at Co/Pt nano-contacts through a thin AlO x barrier. We found a 50-K/V change that can be attributed to the injection of electrons through nano-contacts.

  5. Nano Copper Oxide-Modified Carbon Cloth as Cathode for a Two-Chamber Microbial Fuel Cell

    Science.gov (United States)

    Dong, Feng; Zhang, Peng; Li, Kexun; Liu, Xianhua; Zhang, Pingping

    2016-01-01

    In this work, Cu2O nanoparticles were deposited on a carbon cloth cathode using a facile electrochemical method. The morphology of the modified cathode, which was characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) tests, showed that the porosity and specific surface area of the cathode improved with longer deposition times. X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) results showed that cupric oxide and cuprous oxide coexisted on the carbon cloth, which improved the electrochemical activity of cathode. The cathode with a deposition time of 100 s showed the best performance, with a power density twice that of bare carbon cloth. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) results revealed that moderate deposition of nano copper oxide on carbon cloth could dramatically reduce the charge transfer resistance, which contributed to the enhanced electrochemical performance. The mediation mechanism of copper oxide nanocatalyst was illustrated by the fact that the recycled conversion between cupric oxide and cuprous oxide accelerated the electron transfer efficiency on the cathode.

  6. Nano Copper Oxide-Modified Carbon Cloth as Cathode for a Two-Chamber Microbial Fuel Cell

    Directory of Open Access Journals (Sweden)

    Feng Dong

    2016-12-01

    Full Text Available In this work, Cu2O nanoparticles were deposited on a carbon cloth cathode using a facile electrochemical method. The morphology of the modified cathode, which was characterized by scanning electron microscopy (SEM and Brunauer-Emmett-Teller (BET tests, showed that the porosity and specific surface area of the cathode improved with longer deposition times. X-ray photoelectron spectroscopy (XPS and cyclic voltammetry (CV results showed that cupric oxide and cuprous oxide coexisted on the carbon cloth, which improved the electrochemical activity of cathode. The cathode with a deposition time of 100 s showed the best performance, with a power density twice that of bare carbon cloth. Linear sweep voltammetry (LSV and electrochemical impedance spectroscopy (EIS results revealed that moderate deposition of nano copper oxide on carbon cloth could dramatically reduce the charge transfer resistance, which contributed to the enhanced electrochemical performance. The mediation mechanism of copper oxide nanocatalyst was illustrated by the fact that the recycled conversion between cupric oxide and cuprous oxide accelerated the electron transfer efficiency on the cathode.

  7. Preparation and properties of blended graphene oxide-nano SiO2/TPU composites%共混型石墨烯-nano SiO2/TPU复合材料的制备与性能

    Institute of Scientific and Technical Information of China (English)

    蔺海兰; 朱庆兰; 卞军; 周醒; 王正君; 鲁云

    2016-01-01

    采用熔融共混技术制备了氧化石墨烯(GO)-nano SiO2杂化材料填充改性的形状记忆热塑性聚氨酯(GO-nano SiO2/TPU)复合材料,探讨了 GO-nano SiO2杂化材料对复合材料力学性能、熔融指数及形状记忆性能的影响。结果表明:GO-nano SiO2含量对 GO-nano SiO2/TPU 复合材料的力学性能有明显的影响,其含量为0.5 wt%~1 wt%时,GO-nano SiO2/TPU复合材料的综合力学性能较好。熔融指数分析表明,填料的加入会降低材料的加工流动性能。形状记忆性能研究表明,加入 GO-nano SiO2杂化材料使得 GO-nano SiO2/TPU 复合材料的形状固定率先降低后上升,在含量为1 wt%后上升趋势更加明显;而形状回复率随填料含量的增加而呈降低趋势,并且在100℃高温这种变化趋势更加明显和稳定,回复温度越高,形状回复率越好。%Graphene oxide(GO)-nano SiO2 hybrid materials filled modified shape memory thermoplastic polyure-thane (GO-nano SiO2/TPU)composites were prepared through melt blending technology.The effects of GO-nano SiO2 hybrid materials on the mechanical properties,melt index and shape memory properties of composites were in-vestigated.The results show that the content of GO-nano SiO2 has an obvious influence on the mechanical properties of GO-nano SiO2/TPU composites.When the content of GO-nano SiO2 is in the range of 0.5wt%-1wt%,the GO-nano SiO2/TPU composites show the best comprehensive mechanical properties.Melting index analysis indicates that the incorporation of filler decreases the flowability of materials.Shape memory property tests indicate that the shape fixed rate of GO-nano SiO2/TPU composites decreases firstly,and then increases with addition of GO-nano SiO2 hybrid material.Especially the rising trend is more obvious when the filler content is higher than 1 wt%.The shape recovery rate decreases with the increasing of filler content.And this trend is more obvious and stable at 100 ℃ high temperature

  8. Anormalous Optical Absorption in Porous Al_2O3 Host Matrix---Nano-Oxide Particle Nanocomposites

    Science.gov (United States)

    Zhang, Lide; Zhang, Biao; Mo, Chimei

    1996-03-01

    Porous Al_2O3 host matrix---nano-γ-Fe_2O3 particle composites (porous nanocomposite) were prepared by pyrolysis of Fe(NO_3)_39H_2O in porous nano- Al_2O3 matrix at 250^0C. Comparing with simple nanocomposites formed by mixing nano-γ-Fe_2O3 and compacting at room temperature, followed by annealing at 250^0C, the following anomalous optical behaviors were observed: for porous nanocomposite containing 5% Fe_2O_3, the aborption edge shifts obviously from 827nm to 543nm, and with increasing dopping amount of Fe_2O3 from 5% to 70%, blue shift phenomina decreases. Namely, the absorption edge moves from 543nm to 710nm. The mechanism of shift of the absorption edge is discussed.

  9. The role of allophane nano-structure and Fe oxide speciation for hosting soil organic matter in an allophanic Andosol

    Science.gov (United States)

    Filimonova, Svetlana; Kaufhold, Stephan; Wagner, Friedrich E.; Häusler, Werner; Kögel-Knabner, Ingrid

    2016-05-01

    We evaluated the impact of nano-structural characteristics of allophanic compounds and Fe oxide speciation on the efficiency of organo-mineral interactions in an allophanic Andosol derived from volcanic ash (Eifel mountains, Germany). The samples selected for our work represented a gradient from: (i) a pure synthetic allophane and (ii) model organo-mineral mixtures to (iii) particle size fractions of the natural Andosol. We thus aimed to link the processes operating at the individual molecular scale to the phenomena active at the aggregate scale. For a non-destructive characterization of the samples, we applied 129Xe NMR spectroscopy of adsorbed Xe atoms (to identify the mineral nano-structure and surface acid centres), ESEM (verifying the nano-spherical structure of allophane), 13C CPMAS NMR (for the nature of the soil organic matter (SOM)), 57Fe Mössbauer spectroscopy (Fe oxide speciation), and N2 adsorption (contribution of micro- and mesoporosity). By using the atomic probe Xe, we obtained evidence for a coupled mechanism of adsorption onto allophane requiring both the narrow pores (voids formed by the primary nano-spherules) and the acid centres located at the defect surfaces of the primary spherules. The validity of this coupled mechanism for the sorption of organic matter was confirmed by the concomitant blocking of acid centres (129Xe NMR data) and the decrease of the N2-available pore volumes (Vmicro and Vmeso) in the model samples DOM/- and NOM/allophane (DOM = dissolved OM, NOM = natural OM). In the Andosol, the high resistance of SOM against oxidation (OCresist = 15-50%) was combined with preferential accumulation of certain organic compounds, e.g. potentially labile substrates such as carbohydrates, and the low molecular weight species such as amino acids. This feature was attributed to the peculiar microporous tortuous structure of allophane aggregates that likely impose certain criteria for the chemical nature and size of mineral-bound SOM. On the

  10. Nano-zinc oxide incorporated graphene oxide/nanocellulose composite for the adsorption and photo catalytic degradation of ciprofloxacin hydrochloride from aqueous solutions.

    Science.gov (United States)

    Anirudhan, T S; Deepa, J R

    2017-03-15

    Purpose of this study is to report the synthetic procedure of a novel photo catalyst, nano zinc oxide incorporated graphene oxide/nanocellulose (ZnO-GO/NC) for the effective adsorption and subsequent photo degradation of ciprofloxacin (CF), an antibiotic widely used in the poultry. Self cleaning property in cellulose was achieved by introducing a nano zinc oxide incorporated graphene oxide into nanocellulose (NC) matrix. By incorporating nano zinc oxide (ZnO) in graphene oxide (GO), band gap could be tuned to 2.4eV and after the composite formation with NC, the band gap was enhanced to 2.8eV which is in the visible region. Thus the degradation of the CF was achieved under the visible light. Photo degradation was due to electron hole interaction. The step wise modification in the synthesis ZnO-GO/NC was characterized using FT-IR, XRD, SEM, EDS, AFM, DRS-UV and BET N2 adsorption isotherm techniques. The values of surface area, pore volume and pore radius were found to be 12.68m(2)/g, 0.026mL/g and 12.5nm, respectively. Efficiency in the adsorption process of CF onto ZnO-GO/NC was verified by batch adsorption technique. The optimum pH was found to be 5.5 and dose of the ZnO-GO/NC was optimized as 2.0g/L. Equilibrium was attained at 120min and the adsorption of drug followed second-order kinetics. Sips isotherm was the best fitted model and could explain the nature of interaction of CF with ZnO-GO/NC. The studies revealed that the degradation followed first-order kinetics and the optimum pH for the degradation process was found to be 6.0 and achieved a maximum degradation efficiency of 98.0%. The reusability of ZnO-GO/NC after five consecutive cycles indicated it to be a potential candidate for the removal and degradation of CF from aquatic environment. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Antimicrobial Effect of Nano-Zinc Oxide and Nano-Chitosan Particles in Dental Composite Used in Orthodontics

    Directory of Open Access Journals (Sweden)

    AmirHossein Mirhashemi

    2015-10-01

    Full Text Available Background: Incidence of  white  spots due  to  demineralization of  enamel  and  gingival problems  is  an  unacceptable  result  of  orthodontic  treatment.  Plaque  accumulation  and bacterial biofilm growth are responsible for these phenomena. The resin-based dental composites used as bonding agents in orthodontics play a major role in mentioned problems. As recent researches assert the antimicrobial effects of chitosan (CS and zinc oxide (ZnO nanoparticles  (NPs,  it  seems  that  adding  these  nanoparticles  to  the  composite  can  be beneficial in reducing the number and function of microorganisms. The aim of this study was to  evaluate  the  antimicrobial  effects  of  ZnO-NP  and  CS-NP-containing  orthodontic composite.Methods: Antibacterial effectiveness of ZnO-NPs and CS-NPs was assessed in four groups against Streptococcus mutans, Streptococcus sanguis and Lactobacillus acidophilus grown both planktonic and as a biofilm on composites. One group as the unmodified control group and  three  groups  consisting  of  three  different  concentrations of  ZnO-NPs  and  CS-NPs mixture: 1%, 5% and 10% (1:1 w/w. 108 CFU/ml microorganism suspensions were provided with spectrophotometer. Biofilm formation was quantified by viable counts. Disc agar diffusion (DAD test was carried out to determine antimicrobial effects of nanoparticles by measuring the inhibition diameter on brain heart infusion agar plates. Finally,viable counts of microorganisms on days 3, 15 and 30 were collected for the antimicrobial effects of eluted components from composite discs.Results: In biofilm formation test, a reduction in bacterial counts was observed with 10% nanoparticle-containing composites compared with their unmodified counterpart. In the DAD test only 10% nanoparticle-containing specimens showed statistically significant inhibition. The only noticeable datain eluted component test was on day 30 for 10

  12. Submicron and nano formulations of titanium dioxide and zinc oxide stimulate unique cellular toxicological responses in the green microalga Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Gunawan, Cindy, E-mail: c.gunawan@unsw.edu.au [ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering, The University of New South Wales, Sydney, NSW (Australia); Sirimanoonphan, Aunchisa [ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering, The University of New South Wales, Sydney, NSW (Australia); Teoh, Wey Yang [Clean Energy and Nanotechnology (CLEAN) Laboratory, School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region (Hong Kong); Marquis, Christopher P., E-mail: c.marquis@unsw.edu.au [School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW (Australia); Amal, Rose [ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering, The University of New South Wales, Sydney, NSW (Australia)

    2013-09-15

    Highlights: • Uptake of TiO{sub 2} solids by C. reinhardtii generates ROS as an early stress response. • Submicron and nanoTiO{sub 2} exhibit benign effect on cell proliferation. • Uptake of ZnO solids and leached zinc by C. reinhardtii inhibit the alga growth. • No cellular oxidative stress is detected with submicron and nano ZnO exposure. • The toxicity of particles is not necessarily mediated by cellular oxidative stress. -- Abstract: The work investigates the eco-cytoxicity of submicron and nano TiO{sub 2} and ZnO, arising from the unique interactions of freshwater microalga Chlamydomonas reinhardtii to soluble and undissolved components of the metal oxides. In a freshwater medium, submicron and nano TiO{sub 2} exist as suspended aggregates with no-observable leaching. Submicron and nano ZnO undergo comparable concentration-dependent fractional leaching, and exist as dissolved zinc and aggregates of undissolved ZnO. Cellular internalisation of solid TiO{sub 2} stimulates cellular ROS generation as an early stress response. The cellular redox imbalance was observed for both submicron and nano TiO{sub 2} exposure, despite exhibiting benign effects on the alga proliferation (8-day EC50 > 100 mg TiO{sub 2}/L). Parallel exposure of C. reinhardtii to submicron and nano ZnO saw cellular uptake of both the leached zinc and solid ZnO and resulting in inhibition of the alga growth (8-day EC50 ≥ 0.01 mg ZnO/L). Despite the sensitivity, no zinc-induced cellular ROS generation was detected, even at 100 mg ZnO/L exposure. Taken together, the observations confront the generally accepted paradigm of cellular oxidative stress-mediated cytotoxicity of particles. The knowledge of speciation of particles and the corresponding stimulation of unique cellular responses and cytotoxicity is vital for assessment of the environmental implications of these materials.

  13. Development of a novel in silico model of zeta potential for metal oxide nanoparticles: a nano-QSPR approach

    Science.gov (United States)

    Wyrzykowska, Ewelina; Mikolajczyk, Alicja; Sikorska, Celina; Puzyn, Tomasz

    2016-11-01

    Once released into the aquatic environment, nanoparticles (NPs) are expected to interact (e.g. dissolve, agglomerate/aggregate, settle), with important consequences for NP fate and toxicity. A clear understanding of how internal and environmental factors influence the NP toxicity and fate in the environment is still in its infancy. In this study, a quantitative structure-property relationship (QSPR) approach was employed to systematically explore factors that affect surface charge (zeta potential) under environmentally realistic conditions. The nano-QSPR model developed with multiple linear regression (MLR) was characterized by high robustness ({{{Q}}{{2}}}{{CV}}=0.90) and external predictivity ({{{Q}}{{2}}}{{EXT}}=0.93). The results clearly showed that zeta potential values varied markedly as functions of the ionic radius of the metal atom in the metal oxides, confirming that agglomeration and the extent of release of free MexOy largely depend on their intrinsic properties. A developed nano-QSPR model was successfully applied to predict zeta potential in an ionized solution of NPs for which experimentally determined values of response have been unavailable. Hence, the application of our model is possible when the values of zeta potential in the ionized solution for metal oxide nanoparticles are undetermined, without the necessity of performing more time consuming and expensive experiments. We believe that our studies will be helpful in predicting the conditions under which MexOy is likely to become problematic for the environment and human health.

  14. Crossover from disordered to core-shell structures of nano-oxide Y{sub 2}O{sub 3} dispersed particles in Fe

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, M. P.; Wang, L. M.; Gao, F., E-mail: gaofeium@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Lu, C. Y. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, Liaoning 110819 (China); Lu, Z. [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, Liaoning 110819 (China); Shao, L. [Department of Nuclear Engineering, Texas A& M University, College Station, Texas 77843 (United States)

    2016-07-18

    Molecular dynamic simulations of Y{sub 2}O{sub 3} in bcc Fe and transmission electron microscopy (TEM) observations were used to understand the structure of Y{sub 2}O{sub 3} nano-clusters in an oxide dispersion strengthened steel matrix. The study showed that Y{sub 2}O{sub 3} nano-clusters below 2 nm were completely disordered. Y{sub 2}O{sub 3} nano-clusters above 2 nm, however, form a core-shell structure, with a shell thickness of 0.5–0.7 nm that is independent of nano-cluster size. Y{sub 2}O{sub 3} nano-clusters were surrounded by off-lattice Fe atoms, further increasing the stability of these nano-clusters. TEM was used to corroborate our simulation results and showed a crossover from a disordered nano-cluster to a core-shell structure.

  15. STUDY OF ANODIC OVERVOLTAGE IN NEODYMIUM ELECTROLYSIS

    Institute of Scientific and Technical Information of China (English)

    K.R. Liu; J.S. Chen; Q. Han; X.J. Wei

    2003-01-01

    The anodic overvoltage of neodymium electrolysis was determined by slow scanning oscillogram. The effects of some factors, i.e. the temperature, the anodic current density, the concentration of Nd2O3 and the components of the electrolyte were investigated and the approaches to decrease the anodic overvoltage were also discussed. The results show that the anodic overvoltage increases with the anodic current density and decreases with the increasing temperature. The linear relation between the anodic overvoltage and the current density corresponding to Tafel equation is determined to some extent. The anodic overvoltage decreases with the increasing concentrations of LiF and NdF3. It also decreases by controlling the anodic current density properly, increasing the temperature or the concentrations of LiF and NdF3 and the reducing polar distance.

  16. Room-temperature solution-processed and metal oxide-free nano-composite for the flexible transparent bottom electrode of perovskite solar cells.

    Science.gov (United States)

    Lu, Haifei; Sun, Jingsong; Zhang, Hong; Lu, Shunmian; Choy, Wallace C H

    2016-03-21

    The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self-assembly approach under ambient atmosphere, which can effectively prevent the penetration of liquid or gaseous halides and their corrosion against the silver nano-network underneath. Importantly, we simultaneously achieve good work function alignment and surface wetting properties for a practical bottom electrode by controlling the degree of reduction of GO flakes. Finally, flexible PVSC adopting the room-temperature and solution-processed nano-composite as the flexible transparent bottom electrode has been demonstrated on a polyethylene terephthalate (PET) substrate. As a consequence, the demonstration of our room-temperature solution-processed and metal oxide-free flexible transparent bottom electrode will contribute to the emerging large-area flexible PVSC technologies.

  17. Neodymium YAG Lasers. Citations from the NTIS data base

    Science.gov (United States)

    Carrigan, B.

    1980-07-01

    Federally funded research reports on lasing of neodymium doped yttrium aluminum garnet are cited. Studies on design, fabrication, quantum efficiency, light pulses, stabilization, and testing are covered. Optical pumping, mode locking, frequency conversion, and modulation of these lasers are discussed. Laser applications such as optical communication, range finding, and tracking are included. Safety hazards and radiation damage related to neodymium YAG lasers are also covered. This updated bibliography contains 181 citations, 15 of which are new entries to the previous edition.

  18. The Effects of Zinc and Iron Oxide Nano-Particles on The Growth and Ion Content of Two Corn Cultivars in Different Soil Salinity

    Directory of Open Access Journals (Sweden)

    2014-07-01

    Full Text Available This study was conducted in order to evaluate the effects of foliar application of nano-particles and ordinary bulk materials of zinc and iron oxide was studied in two corn genotypes (S.C 704 and seed mass in different soil salinity (0,75,150 mM NaCl. The experiment was arranged as factorial in a randomized complete block design with four replications. The results showed that in saline condition Leaf area, shoot and root dry matter, photochemical efficiency, the concentration of K, Fe and Zn in shoot decreased and that of Na and the Na/K ratio increased under saline condition. The interactions of salinity and genotype were significant on leaf area, shoot and root dry matter, Na/K ratio and photochemical efficiency. The application of nano-particles of iron and zinc oxide increased shoot dry matter to a greater degree as compared with ordinary bulk materials. Under saline condition, the application of iron oxide in the form of nano-particles had higher effect on iron uptake by corn plants. However, with an increase in salinity level the superiority of nano form decreased. The application of Nano-particles of iron and zinc as compared to ordinary bulk materials was more effective in alleviating the negative effects of salt stress on the accumulation of zinc in tested plants. This was not evidence in terms of iron accumulation. The results from this experiment showed that the application of nano-particles of iron and zinc promoted plant growth to a greater degree in comparison to ordinary materials of these nutrients. However, the application of nano particles had no advantage in alleviating the effects of salinity on plant growth.

  19. Nano-biointeractions of PEGylated and bare reduced graphene oxide on lung alveolar epithelial cells: A comparative in vitro study.

    Science.gov (United States)

    Reshma, S C; Syama, S; Mohanan, P V

    2016-04-01

    Graphene and its derivatives have garnered significant scientific interest and have potential use in nano-electronics as well as biomedicine. However the undesirable biological consequence, especially upon inhalation of the particle, requires further investigations. This study aimed to elucidate the nano-biointeractions of PEGylated reduced graphene oxide (PrGO) and reduced graphene oxide (rGO) with that of lung alveolar epithelial cells (A549). Both nanomaterials showed dose dependent decrease in cell viability and alteration of cell morphology after 24h. Upon intracellular uptake of PrGO, it elicited oxidative stress mediated apoptosis in the cells by inducing ROS, loss of mitochondrial membrane potential (MMP) and inflammatory response by NF-κB activation. Conversely, rGO was found to scavenge ROS efficiently except at high dose after 24h. It was found that ROS at high dose of rGO prompted loss of MMP. rGO was found to adhere to the cell membrane, where it is assumed to bind to cell surface Toll like receptors (TLRs) thereby activating NF-κB mediated inflammatory response. All these events culminated in an increase in apoptosis of A549 cells after 24h of rGO exposure. It was also noticed that both the nanomaterials did not initiate lysosomal pathway but instead activated mitochondria mediated apoptosis. This study highlights the possible adverse toxic effect of PrGO and rGO upon inhalation and persistence of these particles in the lungs. Further research is required to comprehend the biological response of PrGO and rGO so as to advance its biomedical application and safety.

  20. Organic-inorganic hybrid polyionic liquid based polyoxometalate as nano porous material for selective oxidation of sulfides

    Science.gov (United States)

    Rafiee, Ezzat; Shahebrahimi, Shabnam

    2017-07-01

    Organic-inorganic hybrid nano porous materials based on poly(ionic liquid)-polyoxometalate (PIL-POM) were reported. These hybrid materials were synthesized by the reaction of 4-vinyl pyridine with 1,3-propanesultone, followed by the polymerization and also sulfonate-functionalized cross-linked poly(4-vinylpyridine) and combining these polymers with H5PMo10V2O40 (PMo10V2). Activity of prepared PIL-PMo10V2 hybrids were investigated as catalysts for oxidation of sulfides with H2O2 as oxidant. For understanding catalytic activities of the PIL-PMo10V2 hybrids in oxidation of sulfides, effect of catalyst composition, substrate, and reaction conditions were studied. The results show that the PIL-PMo10V2 hybrids are active as selective heterogeneous catalysts for oxidation of sulfides and can be recovered and reused. The catalyst was characterized by FT-IR, TGA-DSC, XRD, SEM/EDX, BET, CV and zeta potential measurement. Also, average molecular weight of prepared catalysts were measured.

  1. Evaluating the potential of three Fe- and Mn-(nano)oxides for the stabilization of Cd, Cu and Pb in contaminated soils.

    Science.gov (United States)

    Michálková, Zuzana; Komárek, Michael; Šillerová, Hana; Della Puppa, Loïc; Joussein, Emmanuel; Bordas, François; Vaněk, Aleš; Vaněk, Ondřej; Ettler, Vojtěch

    2014-12-15

    The potential of three Fe- and Mn-(nano)oxides for stabilizing Cd, Cu and Pb in contaminated soils was investigated using batch and column experiments, adsorption tests and tests of soil microbial activity. A novel synthetic amorphous Mn oxide (AMO), which was recently proposed as a stabilizing amendment, proved to be the most efficient in decreasing the mobility of the studied metals compared to nano-maghemite and nano-magnetite. Its application resulted in significant decreases of exchangeable metal fractions (92%, 92% and 93% decreases of Cd, Cu and Pb concentrations, respectively). The adsorption capacity of the AMO was an order of magnitude higher than those recorded for the other amendments. It was also the most efficient treatment for reducing Cu concentrations in the soil solution. No negative effects on soil microorganisms were recorded. On the other hand, the AMO was able to dissolve soil organic matter to some extent. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Synthesis of zinc oxide nano-particles by mechano-thermal route

    Science.gov (United States)

    Karimi, S.; Ataie, A.; Nozari, A.

    2012-09-01

    ZnO nano-particles were synthesized via mechano-thermal route using ZnSO4.H2O and Na2CO3 as starting materials. The mixture of powders was milled for 5, 10 and 15 in a high energy planetary ball mill, then heat treated at 300 °C for 1 hour. XRD results of the heat treated sample at 300 °C revealed a single phase nano-crystalline ZnO phase with a mean crystallite size of 18 nm. FESEM micrographs of the heat treated sample showed that mean particle size of the ZnO decreased from 150 nm for 5-hour milled sample to 25 nm for 15-hour milled sample. It was also found that the optical properties of the samples varied as a function of milling time.

  3. Synthesis, characterization and application of a nano-manganese-catalyst as an efficient solid catalyst for solvent free selective oxidation of ethylbenzene, cyclohexene, and benzylalcohol

    Science.gov (United States)

    Habibi, Davood; Faraji, Ali Reza

    2013-07-01

    The object of this study is to synthesize the heterogeneous Mn-nano-catalyst (MNC) which has been covalently anchored on a modified nanoscaleSiO2/Al2O3, and characterized by FT-IR, UV-Vis, CHN elemental analysis, EDS, TEM, and EDX. The method is efficient for the highly selective oxidation of ethylbenzene, cyclohexene, and benzylalcohol without the need to any solvents, using tert-butyl hydroperoxide (TBHP) as an oxidant. Oxidation of ethylbenzene, cyclohexene, and benzylalcohol gave acetophenone, 2-cyclohexene-1-one and benzaldehyde, respectively, as major products. Reaction conditions have been optimized by considering the effect of various factors such as reaction time, amounts of substrates and oxidant, Mn-nano-catalyst and application of various solvents.

  4. Self-organized titanium oxide nano-channels for resistive memory application

    Energy Technology Data Exchange (ETDEWEB)

    Barman, A.; Saini, C. P.; Dhar, S.; Kanjilal, A., E-mail: aloke.kanjilal@snu.edu.in [Department of Physics, School of Natural Sciences, Shiv Nadar University, NH-91, Tehsil Dadri, Gautam Buddha Nagar, Uttar Pradesh 201 314 (India); Sarkar, P. [Department of Physics, National Institute of Technology, Silchar, Assam 788 010 (India); Satpati, B.; Bhattacharyya, S. R. [Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India); Kabiraj, D.; Kanjilal, D. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India)

    2015-12-14

    Towards developing next generation scalable TiO{sub 2}-based resistive switching (RS) memory devices, the efficacy of 50 keV Ar{sup +}-ion irradiation to achieve self-organized nano-channel based structures at a threshold fluence of 5 × 10{sup 16} ions/cm{sup 2} at ambient temperature is presented. Although x-ray diffraction results suggest the amorphization of as-grown TiO{sub 2} layers, detailed transmission electron microscopy study reveals fluence-dependent evolution of voids and eventual formation of self-organized nano-channels between them. Moreover, gradual increase of TiO/Ti{sub 2}O{sub 3} in the near surface region, as monitored by x-ray photoelectron spectroscopy, establishes the upsurge in oxygen deficient centers. The impact of structural and chemical modification on local RS behavior has also been investigated by current-voltage measurements in conductive atomic force microscopy, while memory application is manifested by fabricating Pt/TiO{sub 2}/Pt/Ti/SiO{sub 2}/Si devices. Finally, the underlying mechanism of our experimental results has been analyzed and discussed in the light of oxygen vacancy migration through nano-channels.

  5. Synthesis and applications of nano-structured iron oxides/hydroxides

    African Journals Online (AJOL)

    ... for their applications as catalytic materials, wastewater treatment adsorbents, ... This review outlines the work being carried out on synthesis of iron oxides in ... iron oxides, synthesis, catalysts, magnetic properties, biomedical application

  6. Investigation on different oxides as candidates for nano-sized ODS particles in reduced-activation ferritic (RAF) steels

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Jan, E-mail: j.hoffmann@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM-AWP), Karlsruhe (Germany); Rieth, Michael; Lindau, Rainer; Klimenkov, Michael; Möslang, Anton [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM-AWP), Karlsruhe (Germany); Sandim, Hugo Ricardo Zschommler [Department of Materials Engineering, EEL, University of São Paulo, 12600-970 Lorena (Brazil)

    2013-11-15

    Future generation reactor concepts are based on materials that can stand higher temperatures and higher neutron doses in corrosive environments. Oxide dispersion strengthened steels with chromium contents ranging from 9 to 14 wt.% – produced by mechanical alloying – are typical candidate materials for future structural materials in fission and fusion power plants. Y{sub 2}O{sub 3} has proven to be a good candidate for addition to ferritic steels during mechanical alloying to form nano-sized dispersion oxide particles during compacting of the material. These oxide particles have many positive effects on the material such as improved high-temperature properties and higher corrosion resistance. However, there is potential for improvements by choosing different oxides. In this present work, four different oxides (MgO, La{sub 2}O{sub 3}, Ce{sub 2}O{sub 3} and ZrO{sub 2}) are selected by looking at their thermal stabilities and Gibbs free enthalpies of various chemical compositions. These oxides are mixed and mechanically alloyed with ferritic steel powder (Fe13Cr1W0.3Ti) and compared to a reference material produced with Y{sub 2}O{sub 3} (Fe13Cr1W0.3Ti + Y{sub 2}O{sub 3}). The materials were characterized in terms of their mechanical properties and detailed microstructural investigations by transmission electron microscopy and electron backscatter diffraction. All further results of the mechanical testing and microstructural characterizations are analyzed, compared, and discussed in this paper.

  7. Near infrared light-driven water oxidation in a molecule-based artificial photosynthetic device using an upconversion nano-photosensitizer

    NARCIS (Netherlands)

    Liu, X.; Chen, H.C.; Kong, X.; Zhang, Y.; Tu, L.; Chang, Y.; Wu, F.; Wang, T.; Reek, J.N.H.; Brouwer, A.M.; Zhang, H.

    2015-01-01

    We provide the first demonstration of a near infrared light driven water oxidation reaction in a molecule-based artificial photosynthetic device using an upconversion nano-photosensitizer. One very attractive advantage of this system is that using NIR light irradiation does not cause significant pho

  8. WO3 nano-ribbons: their phase transformation from tungstite (WO3·H2O) to tungsten oxide (WO3)

    DEFF Research Database (Denmark)

    Ahmadi, Majid; Sahoo, Satyaprakash; Younesi, Reza

    2014-01-01

    Tungsten oxide (WO3) nano-ribbons (NRs) were obtained by annealing tungstite (WO3·H2O) NRs. The latter was synthesized below room temperature using a simple, environmentally benign, and low cost aging treatment of precursors made by adding hydrochloric acid to diluted sodium tungstate solutions (Na...

  9. Nanocomposites of recycled polycarbonate and nano-zinc oxide (rPC/nZnO): effect of gamma radiation and nano oxide content on the thermal properties; Nanocompositos de policarbonato reciclado e nanooxido de zinco (rPC/nZnO): efeito da radiacao-gama e do teor de nanooxido nas propriedades termicas

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, A.L.F.; Mendes, L.C.; Cestari, S.P., E-mail: anafcarvalho@ima.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Macromoleculas Eloisa Mano; Souza, M.C.L. [Universidade Estadual da Zona Oeste (UEZO), RJ (Brazil)

    2014-07-01

    In order to promote the barrier action to the ultraviolet radiation and increase of mechanical characteristics, nanocomposites of recycled polycarbonate (rPC) and nano-zinc oxide (nZnO) containing 1, 2 and 3 % (wt/wt) of nano oxide were prepared. Since for obtaining nanocomposites and irradiating polymers are promising tools and attractive for improving the material performance, the effects of nano-zinc oxide and gamma radiation, at doses ranged from 10 to 50 kGy, were evaluated in terms of thermal characteristics of the rPC. The rPC/nZnO nanocomposites were characterized by thermogravimetric analysis (TGA) and differential explanatory calorimetry (DSC). There was a progressive decrease of the T{sub g} as function of gamma dosage and nano-zinc oxide content. Initially, the Tonset and Tmax decayed as function of gamma dosage but a recovery was observed. The amount of nano-zinc oxide induced a decreasing of T{sub onset} and T{sub max}. (author)

  10. Silicene Nano-Ribbons: Strong Resistance Towards Oxidation due to sp2 Hybridization of the Si Valence Orbitals

    Science.gov (United States)

    Le Lay, Guy; de Padova, Paola; Quaresima, Claudio; Olivieri, Bruno; Perfetti, Paolo

    2011-03-01

    We have synthesized for the first time silicene, that is, a new silicon allotrope analogous to graphene recently theoretically predicted, in the form of a massively parallel array of quantized zigzag nano-ribbons with a common ``magic'' width of 1.6 nm. They display characteristic linear band dispersions similar to the Dirac cones of graphene, in correspondence with their hexagonal arrangement seen in STM imaging. Here we show, through the angle-dependence of REEL spectra taken at the Si L2 , 3 edge, the typical signatures of 2p --> π * and 2p --> σ * transitions associated with sp 2 hybridization of the Si valence orbitals. We further show through high-resolution synchrotron radiation Si 2p core-level spectroscopy measurements that the afore mentioned silicene grating is very resistant toward oxidation. Typically, the oxygen uptake starts at about 104 higher doses than on the clean Si(111)7x7 surface. Indeed, this striking behavior is directly related to the sp 2 bonding, an additional confirmation of the silicene (i.e., graphene-like) nature of the nano-ribbons.

  11. Toward a robust analytical method for separating trace levels of nano-materials in natural waters: cloud point extraction of nano-copper(II) oxide.

    Science.gov (United States)

    Majedi, Seyed Mohammad; Kelly, Barry C; Lee, Hian Kee

    2014-10-01

    Cloud point extraction (CPE) factors, namely Triton X-114 (TX-114) concentration, pH, ionic strength, incubation time, and temperature, were optimized for the separation of nano-sized copper(II) oxide (nCuO) in aqueous matrices. The kinetics of phase transfer was studied using UV-visible spectroscopy. From the highest separation rate, the most favorable conditions were observed with 0.2 % w/v of TX-114, pH = 9.0, ionic strength of 10 mM NaCl, and incubation at 40 °C for 60 min, yielding an extraction efficiency of 89.2 ± 3.9 % and a preconcentration factor of 86. The aggregate size distribution confirmed the formation of very large nCuO-micelle assemblies (11.9 μm) under these conditions. The surface charge of nCuO was also diminished effectively. An extraction efficiency of 91 % was achieved with a mixture of TX-100 and TX-114 containing 30 wt.% of TX-100. Natural organic and particulate matters, represented by humic acid (30 mg/L) and micron-sized silica particles (50 mg/L), respectively, did not significantly reduce the CPE efficiency (<10 %). The recovery of copper(II) ions (20 mg/L) in the presence of humic acid was low (3-10 %). The spiked natural water samples were analyzed either directly or after CPE by inductively coupled plasma mass spectrometry following acid digestion/microwave irradiation. The results indicated the influence of matrix effects and their reduction by CPE. A delay between spiking nCuO and CPE may also influence the recovery of nCuO due to aggregation and dissolution. A detection limit of 0.04 μg Cu/L was achieved for nCuO.

  12. Comparison on the molecular response profiles between nano zinc oxide (ZnO) particles and free zinc ion using a genome-wide toxicogenomics approach.

    Science.gov (United States)

    Su, Guanyong; Zhang, Xiaowei; Giesy, John P; Musarrat, Javed; Saquib, Quaiser; Alkhedhairy, Abdulaziz A; Yu, Hongxia

    2015-11-01

    Increasing production and applications of nano zinc oxide particles (nano-ZnO) enhances the probability of its exposure in occupational and environmental settings, but toxicity studies are still limited. Taking the free Zn ion (Zn(2+)) as a control, cytotoxicity of a commercially available nano-ZnO was assessed with a 6-h exposure in Escherichia coli (E. coli). The fitted dose-cytotoxicity curve for ZnCl2 was significantly sharper than that from nano-ZnO. Then, a genome-wide gene expression profile following exposure to nano-ZnO was conducted by use of a live cell reporter assay system with library of 1820 modified green fluorescent protein (GFP)-expressing promoter reporter vectors constructed from E. coli K12 strains, which resulted in 387 significantly altered genes in bacterial (p 2) was different from the profile following exposure to 6 mg/L of free zinc ion. The result indicates that these two Zn forms might cause toxicity to bacterial in different modes of action. Our results underscore the importance of understanding the adverse effects elicited by nano-ZnO after entering aquatic environment.

  13. Temperature-Driven Structural and Morphological Evolution of Zinc Oxide Nano-Coalesced Microstructures and Its Defect-Related Photoluminescence Properties.

    Science.gov (United States)

    Lim, Karkeng; Abdul Hamid, Muhammad Azmi; Shamsudin, Roslinda; Al-Hardan, N H; Mansor, Ishak; Chiu, Weesiong

    2016-04-20

    In this paper, we address the synthesis of nano-coalesced microstructured zinc oxide thin films via a simple thermal evaporation process. The role of synthesis temperature on the structural, morphological, and optical properties of the prepared zinc oxide samples was deeply investigated. The obtained photoluminescence and X-ray photoelectron spectroscopy outcomes will be used to discuss the surface structure defects of the prepared samples. The results indicated that the prepared samples are polycrystalline in nature, and the sample prepared at 700 °C revealed a tremendously c-axis oriented zinc oxide. The temperature-driven morphological evolution of the zinc oxide nano-coalesced microstructures was perceived, resulting in transformation of quasi-mountain chain-like to pyramidal textured zinc oxide with increasing the synthesis temperature. The results also impart that the sample prepared at 500 °C shows a higher percentage of the zinc interstitial and oxygen vacancies. Furthermore, the intensity of the photoluminescence emission in the ultraviolet region was enhanced as the heating temperature increased from 500 °C to 700 °C. Lastly, the growth mechanism of the zinc oxide nano-coalesced microstructures is discussed according to the reaction conditions.

  14. Photoinduced electron transfer pathways in hydrogen-evolving reduced graphene oxide-boosted hybrid nano-bio catalyst.

    Science.gov (United States)

    Wang, Peng; Dimitrijevic, Nada M; Chang, Angela Y; Schaller, Richard D; Liu, Yuzi; Rajh, Tijana; Rozhkova, Elena A

    2014-08-26

    Photocatalytic production of clean hydrogen fuels using water and sunlight has attracted remarkable attention due to the increasing global energy demand. Natural and synthetic dyes can be utilized to sensitize semiconductors for solar energy transformation using visible light. In this study, reduced graphene oxide (rGO) and a membrane protein bacteriorhodopsin (bR) were employed as building modules to harness visible light by a Pt/TiO2 nanocatalyst. Introduction of the rGO boosts the nano-bio catalyst performance that results in hydrogen production rates of approximately 11.24 mmol of H2 (μmol protein)(-1) h(-1). Photoelectrochemical measurements show a 9-fold increase in photocurrent density when TiO2 electrodes were modified with rGO and bR. Electron paramagnetic resonance and transient absorption spectroscopy demonstrate an interfacial charge transfer from the photoexcited rGO to the semiconductor under visible light.

  15. Fabrication of Pd Micro-Membrane Supported on Nano-Porous Anodized Aluminum Oxide for Hydrogen Separation.

    Science.gov (United States)

    Kim, Taegyu

    2015-08-01

    In the present study, nano-porous anodized aluminum oxide (AAO) was used as a support of the Pd membrane. The AAO fabrication process consists of an electrochemical polishing, first/second anodizing, barrier layer dissolving and pores widening. The Pd membrane was deposited on the AAO support using an electroless plating with ethylenediaminetetraacetic acid (EDTA) as a plating agent. The AAO had the regular pore structure with the maximum pore diameter of ~100 nm so it had a large opening area but a small free standing area. The 2 µm-thick Pd layer was obtained by the electroless plating for 3 hours. The Pd layer thickness increased with increasing the plating time. However, the thickness was limited to ~5 µm in maximum. The H2 permeation flux was 0.454 mol/m2-s when the pressure difference of 66.36 kPa0.5 was applied at the Pd membrane under 400 °C.

  16. Electrochemical sensing of DNA immobilization and hybridization based on carbon nanotubes/nano zinc oxide/chitosan composite film

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Tao Yang; Da Ming Huang; Kui Jiao

    2008-01-01

    A novel electrochemical DNA biosensor based on zinc oxide (ZnO) nanoparticles and multi-walled carbon nanotubes (MWNTs)for DNA immobilization and enhanced hybridization detection is presented. The MWNTs/nano ZnO/chitosan composite filmmodified glassy carbon electrode (MWNTs/ZnO/CHIT/GCE) was fabricated and DNA probes were immobilized on the electrodesurface. The hybridization events were monitored by differential pulse voltammetry (DPV) using methylene blue (MB) as anindicator. The sensor can effectively discriminate different DNA sequences related to PAT gene in the.transgenic corn, with adetection limit of 2.8×10-12 mol/L of target sequence.2008 Kui Jiao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  17. Surveying and Comparing Thermal Conductivity and Physical Properties of Oil Base NanoFluids Containing Carbon and Metal Oxide Nanotubes

    Directory of Open Access Journals (Sweden)

    H. Ahmadi

    2012-12-01

    Full Text Available In this research, nano materials with tubular structures are added to SAE 20W50 engine oil to study the rate of their effects on the properties of engine oil. Multi-walled carbon nanotubes (MWCNTs and vanadium oxide nanotubes (VONTs has been used as two different additive materials, one of them is carbonic and the other is metallic oxides and their effect on  different parameters containing viscosity, thermal conductivity coefficient, flash point and pour point of engine oil as the quality properties of engine oil has been studied and compared. The samples of two concentrations 0.1 and 0.2 wt% with using planetary ball mill were made. The obtained results show that MWCNTs in all cases, which  have been evaluated, had better functionality with respect to vanadium oxide nanotubes. In the 0.1 wt% concentration, flash point of MWCNTs/oil and VONTs/oil increased about 9.3% and 5.8% respectively. In addition, thermal conductivity of them increased 13.2% and 10.2% respectively.

  18. Fluoride adsorption studies on mixed-phase nano iron oxides prepared by surfactant mediation-precipitation technique

    Energy Technology Data Exchange (ETDEWEB)

    Mohapatra, M., E-mail: mamatamohapatra@yahoo.com [Institute of Minerals and Materials Technology, Acharyavihar, Bhubaneswar 751 013, Orissa (India); Rout, K. [Institute of Minerals and Materials Technology, Acharyavihar, Bhubaneswar 751 013, Orissa (India); Singh, P. [Murdoch University, Perth, Western Australia (Australia); Anand, S. [Institute of Minerals and Materials Technology, Acharyavihar, Bhubaneswar 751 013, Orissa (India); Layek, S.; Verma, H.C. [Indian Institute of Technology, Kanpur (India); Mishra, B.K. [Institute of Minerals and Materials Technology, Acharyavihar, Bhubaneswar 751 013, Orissa (India)

    2011-02-28

    Mixed nano iron oxides powder containing goethite ({alpha}-FeOOH), hematite ({alpha}-Fe{sub 2}O{sub 3}) and ferrihydrite (Fe{sub 5}HO{sub 8}.4H{sub 2}O) was synthesized through surfactant mediation-precipitation route using cetyltrimethyl ammonium bromide (CTAB). The X-ray diffraction, FTIR, TEM, Moessbauer spectroscopy were employed to characterize the sample. These studies confirmed the nano powder contained 77% goethite, 9% hematite and 14% ferrihydrite. Fluoride adsorption onto the synthesized sample was investigated using batch adsorption method. The experimental parameters chosen for adsorption studies were: pH (3.0-10.0), temperature (35-55 deg. C), concentrations of adsorbent (0.5-3.0 g/L), adsorbate (10-100 mg/L) and some anions. Adsorption of fluoride onto mixed iron oxide was initially very fast followed by a slow adsorption phase. By varying the initial pH in the range of 3.0-10.0, maximum adsorption was observed at a pH of 5.75. Presence of either SO{sub 4}{sup 2-} or Cl{sup -} adversely affected the adsorption of fluoride in the order of SO{sub 4}{sup 2-} > Cl{sup -}. The FTIR studies of fluoride loaded adsorbent showed that partly the adsorption on the surface took place at surface hydroxyl sites. Moessbauer studies indicated that the overall absorption had gone down after fluoride adsorption that implies it has reduced the crystalline bond strength. The relative absorption area of ferrihydrite was marginally increased from 14 to 17%.

  19. Fluoride adsorption studies on mixed-phase nano iron oxides prepared by surfactant mediation-precipitation technique.

    Science.gov (United States)

    Mohapatra, M; Rout, K; Singh, P; Anand, S; Layek, S; Verma, H C; Mishra, B K

    2011-02-28

    Mixed nano iron oxides powder containing goethite (α-FeOOH), hematite (α-Fe(2)O(3)) and ferrihydrite (Fe(5)HO(8)·4H(2)O) was synthesized through surfactant mediation-precipitation route using cetyltrimethyl ammonium bromide (CTAB). The X-ray diffraction, FTIR, TEM, Mössbauer spectroscopy were employed to characterize the sample. These studies confirmed the nano powder contained 77% goethite, 9% hematite and 14% ferrihydrite. Fluoride adsorption onto the synthesized sample was investigated using batch adsorption method. The experimental parameters chosen for adsorption studies were: pH (3.0-10.0), temperature (35-55°C), concentrations of adsorbent (0.5-3.0 g/L), adsorbate (10-100 mg/L) and some anions. Adsorption of fluoride onto mixed iron oxide was initially very fast followed by a slow adsorption phase. By varying the initial pH in the range of 3.0-10.0, maximum adsorption was observed at a pH of 5.75. Presence of either SO(4)(2-) or Cl(-) adversely affected the adsorption of fluoride in the order of SO(4)(2-)>Cl(-). The FTIR studies of fluoride loaded adsorbent showed that partly the adsorption on the surface took place at surface hydroxyl sites. Mössbauer studies indicated that the overall absorption had gone down after fluoride adsorption that implies it has reduced the crystalline bond strength. The relative absorption area of ferrihydrite was marginally increased from 14 to 17%. Copyright © 2010 Elsevier B.V. All rights reserved.

  20. Nano-architecture based photoelectrochemical water oxidation efficiency enhancement by CdS photoanodes

    Science.gov (United States)

    Pareek, Alka; Kim, Hyun Gyu; Paik, Pradip; Joardar, Joydip; Borse, Pramod H.

    2017-02-01

    In the present work, 2D nanostructuring has been utilized to impart an efficiency improvement to the hexagonal phase CdS films for the photoelectrochemical (PEC) cells those were deposited by spray pyrolysis technique. By controlling the aerosol droplet- size, population and impingement time during the spray pyrolysis deposition, various nano-features viz. randomly aligned nanorods, nanotubes and nanowires of CdS has been demonstrated for the first time. A growth mechanism has been proposed to predict the temporal evolution of the nanostructures. The prominent nanoscale structures show improved optical properties in the visible range of solar spectrum. The structural studies validate the morphological differences of nanostructures in terms of the texture coefficient analysis as well as 2D micro x-ray diffraction imaging. Electrochemical characterization is carried out to understand the effect of nanostructuring on the PEC performance of the CdS photoanodes in the sulphide (0.1 M Na2S  +  0.02 M Na2SO3) electrolyte at applied bias of 0.2 V (versus SCE). The evolution of morphology from randomly aligned rods to nanowire is responsible for improved photocurrent (3.5 times). CdS film morphology can be tuned to nanotubes, nano- rose buds and nanorod bunches even by doping Zn2+ ions in CdS lattice. Nano-structuring of doped CdS has shown enhanced performance of the photoanodes. The nanotubes structures yielded highest photocurrent density of 1.6 mA cm-2. Whereas modifying the 2D-nanostructured CdS film by simple MoO3 spray coating yields the photocurrent enhancement to 2.1 mA cm-2.

  1. The effect of ultrasonication on the size and morphology of iron oxide - chitosan nano and microparticles

    Energy Technology Data Exchange (ETDEWEB)

    Akın, Deniz; Yakar, Arzu [Department of Chemical Engineering, Afyon Kocatepe University, Afyonkarahisar 03200 (Turkey); Gündüz, Ufuk [Department of Biological Sciences, Middle East Technical University, Ankara 06531 (Turkey)

    2013-12-16

    The aim of this study is to synthesize magnetic Fe{sub 3}O{sub 4}-chitosan nano and microparticles (Fe{sub 3}O{sub 4}-CPs) by suspension cross-linking and ionic gelation methods and investigate the effect of ultrasonication on the size, morphology and magnetic properties. The synthesized particles were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and vibrating sample magnetometry (VSM). The results showed that the ultrasonication decreased the mean particle diameter and enhanced magnetic properties of Fe{sub 3}O{sub 4}-CPs due to the Fe{sub 3}O{sub 4} content.

  2. Phy-chemical Attributes of Nano-scale V2O5/TiO2 Catalyst and Its’ Effect on Soot Oxidation

    OpenAIRE

    Deqing Mei; Lichang Li; Chen Zhu; Xiang Zhao; Yinnan Yuan

    2016-01-01

    The V2O5 catalysts which supported on nano-scale TiO2 with variation of vanadium contents (5%, 10%, 20% and 40%) were prepared by an incipient-wetness impregnation method. The phase structures of nano-scale V2O5/TiO2 catalysts with different loading rates were characterized by Scanning electron microscope (SEM), X-Ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectra. The oxidation activities of catalysts over diesel soot were performed in a themogravimetric analysis (TGA) syst...

  3. Effects of Al2O3 Nano-Particles on Corrosion Performance of Plasma Electrolytic Oxidation Coatings Formed on 6061 Aluminum Alloy

    Science.gov (United States)

    Vakili-Azghandi, Mojtaba; Fattah-alhosseini, Arash; Keshavarz, Mohsen K.

    2016-12-01

    Corrosion resistance improvement of plasma electrolyte oxidation coatings on 6061 aluminum alloy in silicate electrolyte containing Al2O3 nano-particles was studied, with particular emphasis on the microstructure, coating growth, and corrosion behavior in 3.5 wt.% NaCl solution. The microstructure of coatings, their thickness, and phase composition were characterized using scanning electron microscopy and x-ray diffraction. All characterization data showed that the maximum coating thickness and lowest amount of porosity were obtained in a low concentration of KOH, a high concentration of Na2SiO3, and moderate concentration of Al2O3 nano-particles in the electrolyte. This combination describes the optimum plasma electrolytic oxidation electrolyte, which has the best conductivity and oxidizing state, as well as the highest incorporation of electrolyte components in the coating growth process. On the other hand, incorporation and co-deposition of Al2O3 nano-particles were more pronounced than SiO3 2- ions in some level of molar concentration, which is due to the higher impact of electron discharge force on the adsorption of Al2O3 nano-particles. The electrochemical results showed that the best protective behavior was obtained in the sample having a coat with the lowest porosity and highest thickness.

  4. Boundary processes traced by neodymium isotopes

    Science.gov (United States)

    Jeandel, C.; Lacan, F.

    2003-04-01

    Continental margins have been identified as preferential sites for removing of reactive elements from the ocean, on the base of U-series measurements (more specifically 231Pa/230Th). This process is called boundary scavenging (Bacon, 1988). Five years of neodymium isotopes data in water masses along the ocean margins (Indonesia, Papua New Guinea, Greenland-Scotland ridge and Labrador Sea) suggests that Nd is transferred from the sediments to the ocean but the reverse also occurs via the so-called boundary scavenging. These processes are only detectable by isotopic ratio measurements because they affect the isotopic signature of the water mass coming in contact with the margin, without changing its concentration. They can involve much higher fluxes than net input processes: for example, the modification of the AAIW signature along the Papua New Guinea slope involves exchange processes only (Lacan and Jeandel, 2001). Since we suspect that such processes not only affect the Nd oceanic chemistry but also the chemical fate of other reactive elements in the ocean, we suggest that the concept of boundary scavenging should be extended to "boundary exchange".

  5. Human skin penetration and local effects of topical nano zinc oxide after occlusion and barrier impairment.

    Science.gov (United States)

    Leite-Silva, V R; Sanchez, W Y; Studier, H; Liu, D C; Mohammed, Y H; Holmes, A M; Ryan, E M; Haridass, I N; Chandrasekaran, N C; Becker, W; Grice, J E; Benson, H A E; Roberts, M S

    2016-07-01

    Public health concerns continue to exist over the safety of zinc oxide nanoparticles that are commonly used in sunscreen formulations. In this work, we assessed the effects of two conditions which may be encountered in everyday sunscreen use, occlusion and a compromised skin barrier, on the penetration and local toxicity of two topically applied zinc oxide nanoparticle products. Caprylic/capric triglyceride (CCT) suspensions of commercially used zinc oxide nanoparticles, either uncoated or with a silane coating, were applied to intact and barrier impaired skin of volunteers, without and with occlusion for a period of six hours. The exposure time was chosen to simulate normal in-use conditions. Multiphoton tomography with fluorescence lifetime imaging was used to noninvasively assess zinc oxide penetration and cellular metabolic changes that could be indicative of toxicity. We found that zinc oxide nanoparticles did not penetrate into the viable epidermis of intact or barrier impaired skin of volunteers, without or with occlusion. We also observed no apparent toxicity in the viable epidermis below the application sites. These findings were validated by ex vivo human skin studies in which zinc penetration was assessed by multiphoton tomography with fluorescence lifetime imaging as well as Zinpyr-1 staining and toxicity was assessed by MTS assays in zinc oxide treated skin cryosections. In conclusion, applications of zinc oxide nanoparticles under occlusive in-use conditions to volunteers are not associated with any measurable zinc oxide penetration into, or local toxicity in the viable epidermis below the application site.

  6. Cerium and neodymium co-precipitation in molten chloride by wet argon sparging

    Energy Technology Data Exchange (ETDEWEB)

    Vigier, J.F. [CEA, Nuclear Energy Division, RadioChemistry and Processes Department, SMCS/LEPS, F-30207 Bagnols sur Ceze (France); Unite de Catalyse et de Chimie du Solide, UCCS UMR CNRS 8181, Univ. Lille Nord de France, ENSCL-USTL, B.P. 90108, 59652 Villeneuve d' Ascq Cedex (France); Renard, C., E-mail: catherine.renard@ensc-lille.fr [Unite de Catalyse et de Chimie du Solide, UCCS UMR CNRS 8181, Univ. Lille Nord de France, ENSCL-USTL, B.P. 90108, 59652 Villeneuve d' Ascq Cedex (France); Laplace, A. [CEA, Nuclear Energy Division, RadioChemistry and Processes Department, SMCS/LEPS, F-30207 Bagnols sur Ceze (France); Lacquement, J. [CEA, Nuclear Energy Division, DTEC/DIR, F-30207 Bagnols sur Ceze (France); Abraham, F. [Unite de Catalyse et de Chimie du Solide, UCCS UMR CNRS 8181, Univ. Lille Nord de France, ENSCL-USTL, B.P. 90108, 59652 Villeneuve d' Ascq Cedex (France)

    2013-01-15

    Co-precipitations of cerium (III) and neodymium (III) at 10 wt.% in LiCl-CaCl{sub 2} (30-70 mol%) molten salt at 705 Degree-Sign C have been achieved using an original way of precipitation, wet argon sparging. Several CeCl{sub 3}/NdCl{sub 3} ratios have been studied, and the isolated powders were analyzed using different characterization methods including XRD investigations. The lanthanides precipitation yields have been determined around 99.9% using ICP-AES analysis. XRD demonstrated that the precipitates mainly contained mixed oxychloride (Ce{sub 1-x}Nd{sub x})OCl and a small amount of the mixed oxide Ce{sub 1-y}Nd{sub y}O{sub 2-0.5y}. Calcination of these precipitates has resulted in the cerium and neodymium mixed oxides. For the precipitation with a Ce/Nd = 50/50 ratio, an hydroxychloride Ln(OH){sub 2}Cl and the oxychloride Ce{sup IV}(Nd{sub 0.7}Ce{sub 0.3}){sup III}O{sub 3}Cl have been identified as unexpected intermediate compounds.

  7. Radiation Stability of Nanoclusters in Nano-structured Oxide Dispersion Strengthened (ODS) Steels

    Energy Technology Data Exchange (ETDEWEB)

    Certain, Alicia G.; Kuchibhatla, Satyanarayana V N T; Shutthanandan, V.; Hoelzer, D. T.; Allen, T. R.

    2013-03-01

    Nanostructured oxide dispersion strengthened (ODS) steels are considered candidates for nuclear fission and fusion applications at high temperature and dose. The complex oxide nanoclusters in these alloys provide high-temperature strength and are expected to afford better radiation resistance. Proton, heavy ion, and neutron irradiations have been performed to evaluate cluster stability in 14YWT and 9CrODS steel under a range of irradiation conditions. Energy-filtered transmission electron microscopy and atom probe tomography were used in this work to analyze the evolution of the oxide population.

  8. Novel attributes and design considerations of effective oxide thickness in nano DG MOSFETs

    Institute of Scientific and Technical Information of China (English)

    Morteza Charmi

    2015-01-01

    Impacts of effective oxide thickness on a symmetric double-gate MOSFET with 9-nm gate length are studied, using full quantum simulation. The simulations are based on a self-consistent solution of the two-dimensional (2D) Poisson equation and the Schr ¨odinger equation within the non-equilibrium Green’s function formalism. Oxide thickness and gate dielectric are investigated in terms of drain current, on-off current ratio, off current, sub-threshold swing, drain induced barrier lowering, transconductance, drain conductance, and voltage. Simulation results illustrate that we can improve the device performance by proper selection of the effective oxide thickness.

  9. Complementary techniques for solid oxide electrolysis cell characterisation at the micro- and nano-scale

    DEFF Research Database (Denmark)

    Wiedenmann, D.; Hauch, Anne; Grobety, B.

    2010-01-01

    High-temperature steam electrolysis by solid oxide electrolysis cells (SOEC) is a method with great potential for transforming clean and renewable energy from non-fossil sources to synthetic fuels such as hydrogen, methane or dimethyl ether, which have been identified as promising alternative...... energy carriers. With the same technology, fuel gas can be used in a very efficient way to reconvert chemically stored energy into electrical energy, since SOECs also work in the reverse mode, operating as solid oxide fuel cells (SOFC). As solid oxide cells (SOC) perform at high-temperatures (700–900 °C...

  10. Enhanced detection of nitrogen dioxide via combined heating and pulsed UV operation of indium oxide nano-octahedra.

    Science.gov (United States)

    Gonzalez, Oriol; Roso, Sergio; Vilanova, Xavier; Llobet, Eduard

    2016-01-01

    We report on the use of combined heating and pulsed UV light activation of indium oxide gas sensors for enhancing their performance in the detection of nitrogen dioxide in air. Indium oxide nano-octahedra were synthesized at high temperature (900 °C) via vapour-phase transport and screen-printed onto alumina transducers that comprised interdigitated electrodes and a heating resistor. Compared to the standard, constant temperature operation of the sensor, mild heating (e.g., 100 °C) together with pulsed UV light irradiation employing a commercially available, 325 nm UV diode (square, 1 min period, 15 mA drive current signal), results in an up to 80-fold enhancement in sensitivity to nitrogen dioxide. Furthermore, this combined operation method allows for making savings in power consumption that range from 35% to over 80%. These results are achieved by exploiting the dynamics of sensor response under pulsed UV light, which convey important information for the quantitative analysis of nitrogen dioxide.

  11. Enhanced detection of nitrogen dioxide via combined heating and pulsed UV operation of indium oxide nano-octahedra

    Directory of Open Access Journals (Sweden)

    Oriol Gonzalez

    2016-10-01

    Full Text Available We report on the use of combined heating and pulsed UV light activation of indium oxide gas sensors for enhancing their performance in the detection of nitrogen dioxide in air. Indium oxide nano-octahedra were synthesized at high temperature (900 °C via vapour-phase transport and screen-printed onto alumina transducers that comprised interdigitated electrodes and a heating resistor. Compared to the standard, constant temperature operation of the sensor, mild heating (e.g., 100 °C together with pulsed UV light irradiation employing a commercially available, 325 nm UV diode (square, 1 min period, 15 mA drive current signal, results in an up to 80-fold enhancement in sensitivity to nitrogen dioxide. Furthermore, this combined operation method allows for making savings in power consumption that range from 35% to over 80%. These results are achieved by exploiting the dynamics of sensor response under pulsed UV light, which convey important information for the quantitative analysis of nitrogen dioxide.

  12. A Risk Assessment Tool for the Virtual Screening of Metal Oxide Nanoparticles through Enalos InSilicoNano Platform.

    Science.gov (United States)

    Melagraki, Georgia; Afantitis, Antreas

    2015-01-01

    The increasing use of Nanoparticles (NPs) in a wide range of applications has led to a rising concern on the possible toxicological effects that this use may have on human health and the environment. Since experimental toxicity evaluation for the different types of NPs already available, is often expensive and time consuming, several computational approaches are proposed for the risk assessment of NPs. In this work, we have developed a predictive classification model for the toxicological assessment of iron oxide NPs with different core, coating and surface modification based on a number of different properties including size, relaxivities, zeta potential and type of coating. The model was fully validated based on several validation measurements and was released online via Enalos InSilicoNano Platform (http://enalos.insilicotox.com/QNAR_IronOxide_Toxicity/). The developed web service gives the interested user the opportunity to insert the indicated properties and get a toxicity prediction accompanied by an indication of its reliability based on the domain of applicability. This newly introduced web service complements our previously reported efforts to extract important information from available datasets and develop user friendly applications for the toxicity assessment of NPs.

  13. [Synthesis, characterization and photo degradation application for dye-rhodamine B of nano-iron oxide/bentonite].

    Science.gov (United States)

    Liu, Ying; Li, Yi-min; Wen, Li-hua; Hou, Ke-yong; Li, Hai-yang

    2006-10-01

    The iron oxide/bentonite was prepared through a reaction of a solution of OH-Fe salt with bentonite clay dispersion. BET, XRD an d HRTEM were used t o study i ts surface area, microstructure, and average particle size. The iron oxide/bentonite nano composite was developed as the heterogeneous catalyst for successful discoloration and mineralization of dye rhodamine B And the effects of solution pH, H2O2 molar concentration, catalyst loading and initial rhodamine B concentration were studied in detail by photometric method. The process of degradation was traced by UV-Visible spectrum. Besides, the comparison between the heterogeneous photo-Fenton process and homogeneous photo-Fenton process was performed. The result shows that, it has large surface area and mainly consists of high catalytic activity alpha-Fe2O3. The discoloration ratio is up to 97% and the COD(Cr), removal ratio is 71% after 4 h in the presence of pH 3.0, 2.5 x 10(-5) mol x L(-1) rhodamine B 100 mL, 0.3 g x L(-1) catalyst, 10 mmol x L(-1) H2O2 and UV. The rhodamine B degradating speed of heterogeneous photo-Fenton process is much faster than that of homogeneous photo-Fenton process. The catalyst can be reused after being treated.

  14. Mg3(VO4)2-MgO-ZrO2 nano-catalysts for oxidative dehydrogenation of n-butane.

    Science.gov (United States)

    Lee, Jong Kwon; Seo, Hyun; Hong, Ung Gi; Yoo, Yeonshick; Cho, Young-Jin; Lee, Jinsuk; Park, Gle; Chang, Hosik; Song, In Kyu

    2014-11-01

    A series of X-Mg3(VO4)2-MgO-ZrO2 nano-catalysts with different vanadium content (X = 3.3, 5.3, 7.0, 10.2, and 13.4) were prepared by a single-step citric acid-derived sol-gel method for use in the oxidative dehydrogenation of n-butane to n-butene and 1,3-butadiene. The effect of vanadium content of X-Mg3(VO4)2-MgO-ZrO2 nano-catalysts on their physicochemical properties and catalytic activities in the oxidative dehydrogenation of n-butane was investigated. Successful formation of X-Mg3(VO4)2-MgO-ZrO2 nano-catalysts was confirmed by XRD, Raman spectroscopy, and ICP-AES analyses. The catalytic performance of X-Mg3(VO4)2-MgO-ZrO2 nano-catalysts strongly depended on vanadium content. All the X-Mg3(VO4)2-MgO-ZrO2 nano-catalysts showed a stable catalytic performance without catalyst deactivation during the reaction. Among the catalysts tested, 7.0-Mg3(VO4)2-MgO-ZrO2 nano-catalyst showed the best catalytic performance in terms of yield for total dehydrogenation products (TDP, n-butene and 1,3-butadiene). TPRO (temperature-programmed reoxidation) experiments were carried out to measure the oxygen capacity of the catalyst. Experimental results revealed that oxygen capacity of the catalyst was closely related to the catalytic performance. Yield for TDP increased with increasing oxygen capacity of the catalyst.

  15. Characterization of the Tribological Behavior of Oxide-Based NanoMaterials: Final CRADA Report

    Energy Technology Data Exchange (ETDEWEB)

    Fenske, George [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-01-04

    Under the Argonne/Pixelligent cooperative research and development agreement (CRADA – C1200801), Argonne performed labscale tribological tests on proprietary nano-sized ZrO2 material developed by Pixelligent. Pixelligent utilized their proprietary process to prepare variants with different surfactants at different loadings in different carrier fluids for testing and evaluation at Argonne. Argonne applied a range of benchtop tribological test rigs to evaluate friction and wear under a range of conditions (contact geometry, loads, speeds, and temperature) that simulated a broad range of conditions experienced in engines and driveline components. Post-test analysis of worn surfaces provided information on the structure and chemistry of the tribofilms produced during the tests.

  16. Functionalized graphene oxide serves as a novel vaccine nano-adjuvant for robust stimulation of cellular immunity

    Science.gov (United States)

    Xu, Ligeng; Xiang, Jian; Liu, Ye; Xu, Jun; Luo, Yinchan; Feng, Liangzhu; Liu, Zhuang; Peng, Rui

    2016-02-01

    Benefiting from their unique physicochemical properties, graphene derivatives have attracted great attention in biomedicine. In this study, we carefully engineered graphene oxide (GO) as a vaccine adjuvant for immunotherapy using urease B (Ure B) as the model antigen. Ure B is a specific antigen for Helicobacter pylori, which is a class I carcinogen for gastric cancer. Polyethylene glycol (PEG) and various types of polyethylenimine (PEI) were used as coating polymers. Compared with single-polymer modified GOs (GO-PEG and GO-PEI), certain dual-polymer modified GOs (GO-PEG-PEI) can act as a positive modulator to promote the maturation of dendritic cells (DCs) and enhance their cytokine secretion through the activation of multiple toll-like receptor (TLR) pathways while showing low toxicity. Moreover, this GO-PEG-PEI can serve as an antigen carrier to effectively shuttle antigens into DCs. These two advantages enable GO-PEG-PEI to serve as a novel vaccine adjuvant. In the subsequent in vivo experiments, compared with free Ure B and clinically used aluminum-adjuvant-based vaccine (Alum-Ure B), GO-PEG-PEI-Ure B induces stronger cellular immunity via intradermal administration, suggesting promising applications in cancer immunotherapy. Our work not only presents a novel, highly effective GO-based vaccine nano-adjuvant, but also highlights the critical roles of surface chemistry for the rational design of nano-adjuvants.Benefiting from their unique physicochemical properties, graphene derivatives have attracted great attention in biomedicine. In this study, we carefully engineered graphene oxide (GO) as a vaccine adjuvant for immunotherapy using urease B (Ure B) as the model antigen. Ure B is a specific antigen for Helicobacter pylori, which is a class I carcinogen for gastric cancer. Polyethylene glycol (PEG) and various types of polyethylenimine (PEI) were used as coating polymers. Compared with single-polymer modified GOs (GO-PEG and GO-PEI), certain dual

  17. 纳米氧化物太阳能电池研究进展%Research Progress on Nano-Materials of Oxides for Solar Cells

    Institute of Scientific and Technical Information of China (English)

    林红; 焦星剑; 赵晓冲; 郝锋; 李建保

    2011-01-01

    The superiority and the principle of a novel, low-cost solar cells based on dye-sensitized nano-oxides (DSCs) are represented. Nano-oxides have some special applications in the photoanodes and electrolytes of DSCs. Based on our recent work on DSCs, the developments on nano-oxides for photoanodes and electrolytes are reviewed. The preparation methods of nano-oxides used in photoanodes are introduced, and the performance, such as electron transfer and recombination in photoanodes are discussed. Low-temperature methods and performances of nano-oxides used in flexible solar cells are reviewed in detail. The quasi-solid state solar cells based on nano-oxides are also presented.%介绍了新型低成本纳米氧化物染料敏化太阳能电池的优势特点及基本原理.纳米氧化物材料在染料敏化太阳能电池的光阳极和电解质中有着特殊的应用,在电池中起到了非常关键的作用.围绕电池中光阳极和电解质所用的纳米氧化物材料,结合清华大学科研实例,综述了光阳极用纳米氧化物的制备方法及性能,分析了电子传递和复合对电池性能的影响,以及纳米材料的包覆对减少电子复合的作用,指出一维纳米氧化物材料可以形成光阳极中的电荷通道.对于低温纳米氧化物薄膜成膜方法及其在柔性太阳能电池中的应用也做了详细评述.另外,还介绍了纳米氧化物在准固态太阳能电池中的应用.

  18. In vivo biodistribution and toxicology of functionalized nano-graphene oxide in mice after oral and intraperitoneal administration.

    Science.gov (United States)

    Yang, Kai; Gong, Hua; Shi, Xiaoze; Wan, Jianmei; Zhang, Youjiu; Liu, Zhuang

    2013-04-01

    Graphene oxide (GO) and its functionalized derivatives have attracted great attention in biomedicine in recent years. A number of groups including ours have studied the in vivo behaviors of functionalized nano-graphene after intravenous injection or inhalation, and uncovered the surface coating & size dependent biodistribution and toxicology profiles for this type of nanomaterials. However, the fate of GO derivatives in animals after oral feeding and intraperitoneal (i.p.) injection, which are two other major drug administration routes, remain unclear. Therefore, in this work, we sought to systematically investigate in vivo biodistribution and potential toxicity of as-made GO and a number of polyethylene glycol (PEG) functionalized GO derivatives with different sizes and surface coatings, after oral and intraperitoneal administration at high doses. It is found that (125)I labeled PEGylated GO derivatives show no obvious tissue uptake via oral administration, indicating the rather limited intestinal adsorption of those nanomaterials. In contrast, high accumulation of PEGyalted GO derivatives, but not as-made GO, in the reticuloendothelial (RES) system including liver and spleen is observed after i.p. injection. Further investigations based on histological examination of organ slices and hematological analysis discover that although GO and PEGylated GO derivatives would retain in the mouse body over a long period of time after i.p. injection, their toxicity to the treated animals is insignificant. Our work is an important fundamental study that offers a deeper understanding of in vivo behaviors and toxicology of functionalized nano-graphene in animals, depending on their different administration routes.

  19. Field Emission From Ordered Nano-array Structures Based on Porous Aluminum Oxide Templates

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ This thesis reports my research work of fabricating nanostructures by using nanoporous anodic aluminum oxide (AAO) templates and their field emission properties in the past few years. Some important results obtained are as follows: 1. We first proposed a new concept of fabricating field emitters with ordered nanostructures based on porous aluminum oxide templates such as AAO/Al, metal/AAO, PANI/AAO, CNTs/AAO, Si/AAO and did a lot of research in this field.

  20. Research progress in preparation of nano - oxides by hydrothermal method%水热法制备纳米氧化物的研究进展

    Institute of Scientific and Technical Information of China (English)

    郑兴芳

    2009-01-01

    简述了水热法的原理和特点.介绍了水热晶化法、水热氧化法、水热还原法、水热沉淀法、水热分解法、水热合成法制备纳米氧化物的特点和现状,并介绍了水热法与其他方法的联合应用,如:微波-水热法、微乳液-水热法、溶胶(凝胶)-水热法等制备纳米氧化物的研究进展.最后对水热法制备纳米氧化物进行了展望.%Principle and characteristics of hydrothermal method were briefly introduced.Characteristics and present situ - ation of hydrothermal methods,including hydrothermal - crystallization,oxidation,reduction,precipitation,decomposition,and synthesis - methods,of nano - oxides were reviewed.Research progress in combination of hydrothermal method with other synthetic methods,such as microwave-hydrothermal,microemulsion-hydrothermal,and sol(gel)-hydrothermal,which were applied in preparation of nano - oxides were also discussed.At last,preparation of nano - oxides by hydrothermal method was also prospected.

  1. An in situ powder neutron diffraction study of nano-precipitate formation during processing of oxide-dispersion-strengthened ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hongtao, E-mail: hongtao.zhang@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Gorley, Michael J. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Chong, Kok Boon; Fitzpatrick, Michael E. [Materials Engineering, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Roberts, Steve G.; Grant, Patrick S. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

    2014-01-05

    Highlights: • In situ powder neutron diffraction to study precipitate formation in ODS steel. • First real time observation of nano-precipitate formation during processing. • Y{sub 2}O{sub 3} particles were fully dissolved into steel matrix during mechanical alloy. • The precipitation occurred during annealing of as-milled powder above 900 °C. -- Abstract: The evolution of phases in a Fe–14Cr–10Y{sub 2}O{sub 3} (wt%) oxide-dispersion-strengthened ferritic steel during mechanical alloying (MA) and subsequent annealing was studied by high resolution powder neutron diffraction, with emphasis on the kinetics of oxide-based nano-precipitate formation. Y{sub 2}O{sub 3} particles were completely dissolved into the ferritic matrix during MA. The formation of nano-precipitates was then observed by in situ thermo-diffraction experiments during annealing of as-milled powder above 900 °C, supported by scanning electron microscopy. This revealed nano-precipitate coarsening with increasing annealing temperature. Powder microhardness was measured at various processing stages, and hardness changes are discussed in terms of the measured phase fractions, crystallite size and lattice strain at different temperatures and times.

  2. Nano-SiO2 induces apoptosis via activation of p53 and Bax mediated by oxidative stress in human hepatic cell line.

    Science.gov (United States)

    Ye, Yiyi; Liu, Jianwen; Xu, Jianhe; Sun, Lijuan; Chen, Mingcang; Lan, Minbo

    2010-04-01

    Nanoparticles such as nano-SiO(2) are increasingly used in food, cosmetics, diagnosis, imaging and drug delivery. However, toxicological data of nano-SiO(2) on hepatic cells in vitro and their detailed molecular mechanisms still remain unclear. In order to assess toxicity of nano-SiO(2), L-02 cells were exposed to 0.2, 0.4 and 0.6 mg/ml of SiO(2) colloids (21, 48 and 86 nm) for 12, 24, 36 and 48h. Lactate dehydrogenase released from damaged cells were quantified, cellular ultrastructural organization was observed, and the levels of reactive oxygen species (ROS), lipid peroxidation and glutathione were measured. Apoptosis induced by 21 nm SiO(2) was characterized by annexin V-FITC/PI staining and DNA ladder assay. Furthermore, apoptosis related proteins such as p53, Bax and Bcl-2 were analyzed by using western blot analysis. Our data indicated that nano-SiO(2) caused cytotoxicity in size, dose and time dependent manners. Oxidative stress and apoptosis were induced by exposure to 21 nm SiO(2). Moreover, the expression of p53 and Bax was increased in time and dose dependent patterns, whereas the expression of Bcl-2 was not significantly changed. In conclusion, ROS-mediated oxidative stress, the activation of p53 and up-regulation of Bax/Bcl-2 ratio are involved in mechanistic pathways of 21 nm SiO(2) induced apoptosis in L-02 cells.

  3. Optical properties of neodymium doped lanthanum scandium borate

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Won Kweon [Hanseo University, Seosan (Korea, Republic of); Kim, Tae Hoon; Yu, Young Moon [Korea Photonics Technology Institute, Kwangju (Korea, Republic of)

    2001-11-15

    Optical characteristics of neodymium doped lanthanium scandium borate, newly developed crystal, was investigated. Technical description of crystal growth and its dependence on optical property were investigated with comparison to other laser crystals. Its potential as commercial laser crystal for microchip laser fabrication was observed with fundamental lasing experiments. It was possible for lanthanium scandium borate to be highly doped with neodymium ion without crystal defect, and it is an advantage for microchip laser host material. The laser operation was investigated in the fundamental with microchip system.

  4. Tuning size and catalytic activity of nano-clusters of cobalt oxide

    Indian Academy of Sciences (India)

    R Venkat Narayan; Vinod Kanniah; Aruna Dhathathreyan

    2006-03-01

    Cobalt oxides were prepared by three different methods: (1) by reacting cobalt nitrate with oxalic acid, (2) co-precipitating cobalt nitrate with sodium carbonate, and (3) using sodium dodecyl sulphate as organic surfactant. All three samples were characterized before and after calcination by solvent extraction and the resulting products examined by IR spectroscopy. In the case of method 3, the removal of surfactant was followed by TGA studies. Products from all three methods were identified by XRD. Peaks in low angle XRD indicate the porous nature of the oxides. The morphology of the pores was studied by transmission electron microscopy. Some irregular pore structures were obtained for samples from methods 1 and 2, with an average size of 4-6 nm. Only the product from method 3 using SDS as template showed ordered structure and optimum size, and Brunauer-Emmet-Teller surface areas of the as-prepared, as well as the treated samples, exhibited H3 type hysteresis. The samples from the three methods were used as catalysts in the oxidation reaction of cyclohexane under mild conditions and the catalytic efficiency of the cobalt oxide was comparable with mesoporous cobalt oxides.

  5. Size-dependent study of pulmonary responses to nano-sized iron and copper oxide nanoparticles.

    Science.gov (United States)

    Kumar, Rajiv; Nagesha, Dattatri K

    2013-01-01

    The application of nanotechnology in various fields has resulted in a tremendous increase in the synthesis of variety of engineered nanoparticles (NPs). These applications are possible only due to the small size and large surface area of the NPs which imparts them unique properties. Inorganic oxide NPs as iron and copper oxide NPs are widely used in several biomedical and synthetic applications. The beneficial aspects of these NPs are concurrently associated with several drastic and deleterious effects as well. Size of the NPs plays a critical role in systemic clearance from the body. Initial studies have confirmed inflammatory responses in mice associated with non-biodegradable oxide NPs. The associated oxidative stress varied from mild effects to reactive oxygen species generation which can potentiate DNA damage or even induced carcinogenesis. Copper oxide NPs, in particular, induced acute toxicity and inflict neutrophil infiltration. This chapter focuses on the applicability of various in vivo techniques for studying the effect of these NPs, especially on the pulmonary system. These in vivo techniques would certainly provide a better understanding and insight into the mechanistic pathways by which these NPs interact with various organ systems in human body.

  6. Oxidation performance of nano-scale multilayer coatings on {gamma}-TiAl

    Energy Technology Data Exchange (ETDEWEB)

    Ross, I M; Rainforth, W M; Zhou, Z; Walker, J C [Department of Engineering Materials, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Reinhard, C; Ehiasarian, A P; Hovsepian, P E [Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield, S1 1WB (United Kingdom); Braun, R [German Aerospace Centre, Institute of Materials Research, 51170 Koeln (Germany)], E-mail: i.ross@shef.ac.uk

    2008-08-15

    There is a major drive to introduce {gamma}-TiAl into gas turbine engines in order to reduce weight. However, this will require the development of coatings that protect against oxidation at high temperature, but do not adversely affect the mechanical properties. This work reports the high temperature degradation mechanisms of a nanoscale CrAlYN/CrN multilayer coating deposited on {gamma}-TiAl(8Nb) by a combined high power impulse magnetron sputtering / unbalanced magnetron sputtering. Detailed TEM/STEM of FIB prepared specimens from isothermal static oxidation tests at 850 deg. C for up to 1030 hours is presented. The evolution of the complex oxide structure and the implications for future coating development is discussed.

  7. Structural characterization and photoluminescence properties of zinc oxide nano particles synthesized by chemical route method

    OpenAIRE

    P.B. Taunk; Das, R.; D.P. Bisen; Raunak kumar Tamrakar

    2015-01-01

    Nanostructures, crystalline Zinc oxide powder were synthesized by mixing Zinc chloride (0.04M) and sodium hydroxide (0.08M) using chemical route method. 0.001M molar concentrations of TEA (Tri ethanolamine) in aqueous solution used to the growing reaction solution. The powder samples are annealed at 190 °C. The experimental results indicate a successful growth of Zinc oxide in solid form which is not observed ever before. XRD, SEM, TEM and PL were performed to characterize the morphology, gro...

  8. Field Emission From Ordered Nano-array Structures Based on Porous Aluminum Oxide Templates

    Institute of Scientific and Technical Information of China (English)

    WANG; ChengWei

    2001-01-01

    This thesis reports my research work of fabricating nanostructures by using nanoporous anodic aluminum oxide (AAO) templates and their field emission properties in the past few years. Some important results obtained are as follows:  1. We first proposed a new concept of fabricating field emitters with ordered nanostructures based on porous aluminum oxide templates such as AAO/Al, metal/AAO, PANI/AAO, CNTs/AAO, Si/AAO and did a lot of research in this field.  ……

  9. Fabrication of aptamer decorated dextran coated nano-graphene oxide for targeted drug delivery.

    Science.gov (United States)

    Alibolandi, Mona; Mohammadi, Marzieh; Taghdisi, Seyed Mohammad; Ramezani, Mohammad; Abnous, Khalil

    2017-01-02

    In the current study, dextran (DEX) was covalently conjugated to the surface of nano-GO sheets, making stable biocompatible dextran coated GO (GO-DEX). The prepared GO-DEX was nontoxic to 4T1 mammary carcinoma cell line at concentrations up to 300μg/mL. AS1411 aptamer, a ssDNA aptamer which can improve the intracellular uptake by nucleolin recognition, also has been introduced to hydroxyl groups of DEX in GO-DEX to produce GO-DEX-Apt. Moreover, curcumin (CUR), a natural polyphenol, found in the rhizomes of Curcuma longa (turmeric) which shows antineoplastic effects, was loaded onto the GO-DEX and GO-DEX-Apt via π-π stacking interactions with a high loading capacity (∼29wt%). The GO-DEX-Apt-CUR could efficiently enter into 4T1 and MCF-7 nucleolin over-expressed cancer cells confirmed by fluorescence microscope and flowcytometry, and it also showed significantly higher cytotoxicity. These types of targeted nanoscale drug delivery vehicles on the basis of DEX coated GO may find potential application in cancer chemotherapy.

  10. Polyol mediated nano size zinc oxide and nanocomposites with poly(methyl methacrylate

    Directory of Open Access Journals (Sweden)

    2011-07-01

    Full Text Available Organophilic nano ZnO particles have been synthesized in various diols (ethylene glycol – EG, 1,2 propane diol – PD, 1,4 butane diol – BD and tetra(ethylene glycol – TEG in the presence of p-toluenesulfonic acid, p-TsOH, as an end capping agent. The addition of p-TsOH reduces the ZnO particle size and increases its crystallite size. With increasing diol main chain length the ZnO particle size increases (EG (32 nm < PD (33 nm < BD (72 nm < TEG (86 nm. Using the assynthesized and unmodified ZnO nanocomposites with poly(methyl methacrylate, PMMA, matrix have been prepared by the in-situ bulk polymerization of methyl methacrylate, MMA. The addition of surface modifiers is avoided which is an advantage for the application since they can influence other properties of the material. ZnO particles, especially those with smaller particle sizes (EG – 32 nm, PD – 33 nm showed enhanced effect on the thermal stability of PMMA, ultraviolet, UV, absorption and transparency for visible light. Transparent materials with high UV absorption and with enhanced resistance to sunlight were obtained by optimizing the nanocomposite preparation procedure using ZnO particles of about 30 nm size in concentrations between 0.05 and 0.1 wt%. The reported nanocomposite preparation procedure is compatible with the industrial process of PMMA sheet production.

  11. Recycling potential of neodymium: the case of computer hard disk drives.

    Science.gov (United States)

    Sprecher, Benjamin; Kleijn, Rene; Kramer, Gert Jan

    2014-08-19

    Neodymium, one of the more critically scarce rare earth metals, is often used in sustainable technologies. In this study, we investigate the potential contribution of neodymium recycling to reducing scarcity in supply, with a case study on computer hard disk drives (HDDs). We first review the literature on neodymium production and recycling potential. From this review, we find that recycling of computer HDDs is currently the most feasible pathway toward large-scale recycling of neodymium, even though HDDs do not represent the largest application of neodymium. We then use a combination of dynamic modeling and empirical experiments to conclude that within the application of NdFeB magnets for HDDs, the potential for loop-closing is significant: up to 57% in 2017. However, compared to the total NdFeB production capacity, the recovery potential from HDDs is relatively small (in the 1-3% range). The distributed nature of neodymium poses a significant challenge for recycling of neodymium.

  12. 2011 Final Report - Nano-Oxide Photocatalysis for Solar Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Eckstein, James N.; Suslick, Kenneth S.

    2011-10-19

    We have very recently discovered a new hydrogen-producing photocatalyst is BiNbO4. BiNbO4 powders prepared by solid state reaction were tested for photocatalytic activity in methanol solutions under UV irradiation. When the material is tested without the presence of a Pt co-catalyst, photocatalytic activity for H2 evolution is superior to that of TiO2. It was also found that BiNbO4 photodegrades into metallic Bi and reduced Nb oxides after use; materials were characterized by SEM, XRD, and XPS. Adding Pt to the surface of the photocatalyst increases photocatalytic activity and importantly, helps to prevent photodegradation of the oxide material. With 1 wt. % Pt loading, photodegradation is essentially absent. BiNbO4 photodegrades into metallic Bi and reduced Nb oxides after use; materials were characterized by SEM, XRD, and XPS. Adding Pt to the surface of the photocatalyst increases photocatalytic activity and importantly, helps to prevent photodegradation of the oxide material. With 1 wt. % Pt loading, photodegradation is essentially absent.

  13. Where bio meets nano: The many uses for nanoporous aluminium oxide in biotechnology

    NARCIS (Netherlands)

    Ingham, C.J.; Maat, ter J.; Vos, de W.M.

    2012-01-01

    Porous aluminum oxide (PAO) is a ceramic formed by an anodization process of pure aluminum that enables the controllable assembly of exceptionally dense and regular nanopores in a planar membrane. As a consequence, PAO has a high porosity, nanopores with high aspect ratio, biocompatibility and the p

  14. The Effects of Natural Clinoptilolite and Nano-Sized Clinoptilolite Supplementation on Glucose Levels and Oxidative Stress in Rats with Streptozotocin-Induced Diabetes.

    Science.gov (United States)

    Hossein Nia, Behnoosh; Khorram, Sirous; Rezazadeh, Hassan; Safaiyan, Abdolrasol; Tarighat-Esfanjani, Ali

    2017-05-12

    Oxidative stress has a major role in development of diabetic complications. In this study we investigated whether clinoptilolite and nano-sized clinoptilolite could reduce hyperglycemia and oxidative stress in streptozotocin-induced diabetic rats and attempted to determine which intervention was more effective. Thirty-six rats were randomly allocated to 2 groups; 1 group was randomly chosen as a diabetic group and injected with streptozotocin (60 mg/kg body weight in 0.1 mol/L sodium citrate buffer, pH 4.5) to induce diabetes. Three days after diabetes induction, each group (diabetic group and nondiabetic group) was randomly divided into 3 subgroups of 6 animals each ([1] control, [2] 1% clinoptilolite/food, [3] 1% nano-sized clinoptilolite/food). Supplementation was continued for 28 days. Blood glucose was measured 3 times, at the beginning of the study and on the 14th and 28th days. Activity of antioxidant enzymes, including glutathione peroxidase and superoxide dismutase, and levels of total antioxidant capacity, as well as malondialdehyde, were evaluated. Blood glucose and malondialdehyde were significantly elevated, but there were no statistically significant changes in superoxide dismutase, glutathione peroxidase or total antioxidant capacity in diabetic rats. In diabetic rats treated with nano-sized clinoptilolite, blood glucose decreased to near normal levels (12.4 vs. 27.5 mmol/L). No significant changes were found in the other groups. None of the oxidative stress indices showed significant changes in either the treated or untreated rats. Nano-sized clinoptilolite exerted a hypoglycemic effect in streptozotocin-induced diabetic rats but had no significant influence on oxidative stress markers. Copyright © 2017. Published by Elsevier Inc.

  15. The Obtaining of Nano Oxide Systems SiO2-REE with Alkoxide Technology

    Science.gov (United States)

    Amelina, Anna; Grinberg, Evgenii

    A lot of oxides systems with REE as dopants are used in catalytic processes in organic synthesis. They are very perspectives as thermostable coating in aerospace technics. These systems are usually based on silicon or aluminium oxides and doped with rare-earth elements. This systems can be produced by different methods. One of the most perspective of them is “sol-gel”-method with silicium, aluminium and rare-earth alkoxides as a precursor of doped silica and alumina, or their derivatives. Thus the obtaining of composite SiO _{2} - REE oxide materials by the hydrolysis doped with rare-earth elements was suggested. Some of alcoholate derivatives such as El(OR)n were used in this processes. The SiO _{2}- REE oxides were precipitated during the sol-gel process, where tetraethoxysilane (TEOS) as used as SiO _{2} sources. Also it is known that alkoxides of alkali metals, including lithium alkoxides, are widely used in industry and synthetic chemistry, as well as a source of lithium in various mixed oxide compositions, such as lithium niobate, lithium tantalate or lithium silicate. Therefore, we attempted to obtain the lithium silicate, which is also doped with rare-earth elements. Lithium silicate was obtained by alkaline hydrolysis of tetraethoxysilane with lithium alkoxide. Lithium alkoxide were synthesized by dissolving at metal in the corresponding alcohol are examined. The dependence of the rate of dissolving of the metal on the method of mixing of the reaction mixture and the degree of metal dispersion was investigated. The mathematical model of the process was composed and also optimization of process was carried out. Some oxide SiO _{2}, Al _{2}O _{3} and rare-earth nanostructured systems were obtained by sol-gel-method. The size of particle was determined by electron and X-ray spectroscopy and was in the range of 5 - 15 nm. Purity of this oxide examples for contaminating of heavy metals consists n.(1E-4...1E-5) wt%. Sols obtained by this method may be used

  16. Preparation of neodymium-doped yttrium aluminum garnet powders and fibers

    Institute of Scientific and Technical Information of China (English)

    R.López; J.Zárate; E.A.Aguilar; J.Mu(n)oz-Salda(n)a

    2008-01-01

    Using nitrate precursors, a novel spray-drying assisted citrate gel process for the preparation of neodymium-doped yttrium alumi-num garnet (YAG) phase was developed. Synthesis of single-phase polycrystalline YAG was achieved at temperatures as low as 800 ℃ us-ing the spray-drying methodology whilst conventional approaches currently available require 1000 ℃. Initially, a solution was prepared by mixing aluminum and yttrium nitrates, citric acid, etilenglycol and neodymium oxide. This solution was dried by pulverization (spray dryer) to obtain aggregated precursor powders of the compound. These aggregates were calcined at 800, 850 and 900 ℃ to determine the phase evolution from amorphous to crystalline by X-ray diffraction (XRD). The morphology of aggregates was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, through XRD it was determined that the crystallization of YAG phase started at about 800 ℃ without any intermediate phases. The powders were composed of spherical aggregates with an average diame-ter of 1 μm. From these powders, ceramic fibers with additions of 2at.% and 5at.% Nd, were extracted from the melt with diameters ranging from 30 μm to 50 μm.

  17. Condensation reaction in the bandpass reaction cell improves sensitivity for uranium, thorium, neodymium and praseodymium measurements.

    Science.gov (United States)

    Vais, Vladimir; Li, Chunsheng; Cornett, Jack

    2003-09-01

    Condensation reactions in the bandpass reaction cell or dynamic reaction cell (DRC) were used for the determination of actinides and lanthanides such as uranium, thorium, neodymium and praseodymium. These elements react with oxygen reagent gas in the dynamic reaction cell of the ELAN DRC II instrument to give mono- and/or dioxo cationic species (UO(2)+, ThO+, NdO+ and PrO+, respectively). Increasing the oxygen flow rate in the dynamic reaction cell leads to the rapid decrease of the singly charged metal ions accompanied by the fast increase in the intensity of the oxide ion. This phenomenon is used to improve considerably the sensitivity of ICP-MS instruments equipped with a dynamic reaction cell for actinides and lanthanides. Estimated detection limits (EDL) obtained in this work for uranium, thorium, neodymium-144 and praseodymium are 0.022, 1.0, 0.045, and 0.10 ng L(-1), respectively. The detection limit for uranium measured in the standard (vented) mode of an ELAN DRC II was found to be 0.22 ng L(-1), which is an order of magnitude higher compared to the pressurized mode.

  18. Effects of Nano-Zinc oxide and Seed Inoculation by Plant Growth Promoting Rhizobacteria (PGPR on Yield, Yield Components and Grain Filling Period of Soybean (Glycine max L.

    Directory of Open Access Journals (Sweden)

    R. Seyed Sharifi

    2016-02-01

    Full Text Available Introduction Utilizing biological fertilizer is a proper and cheap method for crop production. Potentially, soybean can be used as biological fertilizers and seed inoculation. Zinc is an essential element that have positive effects on plant growth and its development. Canola, sunflower, soybean and safflower are the main cultivated oilseeds in Iran. Soybean production in Iran is very low as compared to other countries. One of the most effective factor in increasing the soybean yield is seed inoculation with plant growth promoting rhizobacteria (PGPR and application of Zinc fertilizer. Some of the benefits provided by PGPR are the ability to produce gibberellic acid, cytokinins and ethylene, N2 fixation, solubilization of mineral phosphates and other nutrients (56. Numerous studies have shown a substantial increase in dry matter accumulation and seed yield following inoculation with PGPR. Seyed Sharifi (45 reported that seed inoculation with Azotobacter chroococcum strain 5 increased all of the growth indices such as total dry matter, crop growth rate and relative growth rate. Increasing and extending the role of biofertilizers such as Rhizobium can reduce the need for chemical fertilizers and decrease adverse environmental effects. Therefore, in the development and implementation of sustainable agricultural techniques, biofertilization has great importance in alleviating environmental pollution and deterioration of the nature. As a legume, soybean can obtain a significant portion (4-85% of its nitrogen requirement through symbiotic N2 fixation when grown in association with effective and compatible Rhizobium strains. Since there is little available information on nano-zinc oxide and seed inoculation by plant growth promoting rhizobacteria (PGPR on yield in the agro-ecological growing zones of Ardabil province of Iran. Therefore, this research was conducted to investigate the effects of nano-zinc oxide and seed inoculation with plant growth

  19. Evaluation of the bactericidal characteristics of nano-copper oxide or functionalized zeolite coating for bio-corrosion control in concrete sewer pipes

    Energy Technology Data Exchange (ETDEWEB)

    Haile, T. [Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, Ont., N6A 5B8 (Canada); Materials Technology Laboratory Branch, Natural Resources Canada, 562 Booth Street, Ottawa, Ont., K1A 0G1 (Canada)], E-mail: thaile@uwo.ca; Nakhla, G. [Department of Chemical and Biochemical Engineering, University of Western Ontario, 1151 Richmond Street, London, Ont., N6A 5B8 (Canada)], E-mail: gnakhla@eng.uwo.ca; Allouche, E. [Trenchless Technology Centre, Louisiana Tech University, 600 W. Arizona, Engr. Annex, P.O. Box 10348, Ruston, LA 71272 (United States)], E-mail: allouche@LaTech.edu; Vaidya, S. [Trenchless Technology Centre, Louisiana Tech University, 600 W. Arizona, Engr. Annex, P.O. Box 10348, Ruston, LA 71272 (United States)], E-mail: sva008@LaTech.edu

    2010-01-15

    The bactericidal characteristics of nano-copper oxide or functionalized zeolite coated concrete pipes against Acidithiobacillus thiooxidans were studied by measuring the temporal variation of bacterial dry cell weight measurement, cellular Adenosine Triphosphate production, as well as oxygen uptake rate of the aforementioned bacterium. Uncorroded (UC), severely corroded (SC), and moderately corroded (MC) concrete pipes were electrochemically coated with a nano-copper oxide, while another uncorroded concrete pipe was used to apply functionalized zeolite coating (Z2). Specimens were characterized by field emission-scanning electron microscopy, and optical microscopy. Oxygen uptake rate of the bacterium was the highest in UC followed by the MC. Oxygen uptake rate and cellular Adenosine Triphosphate decreased progressively in Z2 and SC throughout the duration of the experiment due to decline in live bacterial cell. The maximum bacterial specific growth rate was 1.1 x 10{sup -2} day{sup -1} for both UC and MC, with a decay rates varying from 1.4 x 10{sup -2} to 2.6 x 10{sup -2} day{sup -1}. The minimum concentration limits for the inhibition of the bacterium in the nano-copper oxide coated concrete pipes ranged from 2.3 mg to 2.6 mg Cu per mg dry cell weight.

  20. Synthesis of α-MoO3 nano-flakes by dry oxidation of RF sputtered Mo thin films and their application in gas sensing

    Science.gov (United States)

    Dwivedi, Priyanka; Dhanekar, Saakshi; Das, Samaresh

    2016-11-01

    Synthesis of orthorhombic (α) MoO3 nano-flakes by dry oxidation of RF sputtered Mo thin film is presented. The influence of Mo thickness variation, oxidation temperature and time on the crystallographic structure, surface morphology and roughness of MoO3 thin films was studied using SEM, AFM, XRD and Raman spectroscopy. A structural study shows that MoO3 is polycrystalline in nature with an α phase. It was noticed that oxidation temperature plays an important role in the formation of nano-flakes. The synthesis technique proposed is simple and suitable for large scale productions. The synthesis parameters were optimized for the fabrication of sensors. Chrome gold-based IDE (interdigitated electrodes) structures were patterned for the electrical detection of organic vapors. Sensors were exposed to wide range 5-100 ppm of organic vapors like ethanol, acetone, IPA (isopropanol alcohol) and water vapors. α-MoO3 nano-flakes have demonstrated selective sensing to acetone in the range of 10-100 ppm at 150 °C. The morphology of such nanostructures has potential in applications such as sensor devices due to their high surface area and thermal stability.

  1. Oxidative stress-mediated selective antimicrobial ability of nano-VO2 against Gram-positive bacteria for environmental and biomedical applications

    Science.gov (United States)

    Li, Jinhua; Zhou, Huaijuan; Wang, Jiaxing; Wang, Donghui; Shen, Ruxiang; Zhang, Xianlong; Jin, Ping; Liu, Xuanyong

    2016-06-01

    Vanadium dioxide (VO2) is a unique thermochromic material as a result of its semiconductor-metal transition, holding great promise for energy-saving intelligent windows. Herein, pure nano-VO2 from discrete nanoparticles to continuous films were successfully deposited on quartz glass by controlling the sputtering parameters. It was demonstrated that, for Gram-positive S. aureus and S. epidermidis, the nano-VO2 could effectively disrupt bacteria morphology and membrane integrity, and eventually cause death. By contrast, the nano-VO2 did not exhibit significant toxicity towards Gram-negative E. coli and P. aeruginosa. To our knowledge, this is the first report on a selective antimicrobial effect of nano-VO2 materials on Gram-positive bacteria. Based on the experimental results, a plausible mechanism was proposed for the antimicrobial selectivity, which might originate from the different sensitivity of Gram-positive and Gram-negative bacteria to intracellular reactive oxygen species (ROS) level. Elevated intracellular ROS levels exceed the threshold that bacteria can self-regulate to maintain cellular redox homeostasis and thus cause oxidative stress, which can be alleviated by the intervention of glutathione (GSH) antioxidant. In addition, nano-VO2 did not produce significant cytotoxicity (hemolysis) against human erythrocytes within 12 h. Meanwhile, potential cytotoxicity against HIBEpiC revealed a time- and dose-dependent behavior that might be controlled and balanced by careful design. The findings in the present work may contribute to understanding the antimicrobial behavior of nano-VO2, and to expanding the new applications of VO2-based nanomaterials in environmental and biomedical fields.

  2. Antibacterial properties and mechanism of nano-zinc oxide%纳米氧化锌抗菌性能及机制

    Institute of Scientific and Technical Information of China (English)

    胡占江; 赵忠; 王雪梅

    2012-01-01

    BACKGROUND: The zinc oxide has a good biocompatibility, security and long effectiveness, and can be used as a type of antibacterial material of active oxide category. OBJECTIVE: To summarize the antibacterial properties and mechanism of nano-zinc oxide (nano-ZnO). METHODS: A computer-based online search of related papers from December 1995 to February 2011 was performed in Elsevier (Science Direct) and Web of Science databases using the key words of " antibacterial properties of nano-ZnO" in English, and in CNKI and Wanfang databases using the key words of " antibacterial properti es of nano-ZnO" in Chinese. Totally 75 literatures were selected. RESULTS AND CONCLUSION: The nano-ZnO has a strong bactericidal property in many fields. It can replace other materials of active oxide category based on its good biocompatibility, security and long effectiveness. The antibacterial properties and mechanism of nano-ZnO were summarized in this study from the sides of modified antibacterial properties and the effects of morphology and structure of nano-ZnO on antibacterial properties. However, more studies are in need to solve how to improve the utilization and antibacterial properties, and to expand the applications of nano-ZnO in antibacterial and other fields.%背景:氧化锌作为一种活性氧化物类抗菌材料,拥有良好的生物相容性、安全性以及长效性.目的:总结纳米氧化锌的抗菌性能及其抗菌机制.方法:应用计算机检索1995-12/2011-02 Elsevier (ScienceDirect)及Web of Science期刊引文索引数据库相关文章,检索词为"antibacterial properties of nano-zinc oxide",并限定文章语言种类为English.同时计算机检索1995-12/2011-02 CNKI学术总库及万方数据库相关文章,检索词为"纳米氧化锌抗菌性能",并限定文章语言种类为中文.共检索到文献75 篇.结果与结论:纳米氧化锌在很多方面的杀菌性能都很强,并且由于其良好的生物相容性、安全性以及长效性,

  3. Synthesis and Characterization of Nano-Sized Hexagonal and Spherical Nanoparticles of Zinc Oxide

    Directory of Open Access Journals (Sweden)

    M. A. Moghri Moazzen

    2012-09-01

    Full Text Available ZnO plays an important role in many semiconductors technological aspects.  Here,  direct  precipitation  method  was  employed  for  the synthesis of nano-sized hexagonal ZnO particles, which is based on chemical  reactions between  raw materials used  in  the  experiment. ZnO  nanoparticles  were  synthesized  by  calcinations  of  the  ZnO precursor precipitates  at 250  ˚C  for 3hours. The particle  size  and structure of the products have been confirmed by XRD. The FT-IR study  confirms  the  presence  of  functional  groups.  Also,  the morphology  and  size  distribution  of  ZnO  nanoparticles  was analyzed by TEM images. The optical properties were investigated by UV–Visible  spectroscopy. The XRD  results  show  that  the  size of  the prepared nanoparticles  is  in  the  range  of 20–40 nm, which this value  is  in good agreement with  the TEM  results. The FT-IR spectrum clearly indicates the formation of an interfacial chemical bond between Zn and O. Also  the UV absorption depends on  the particles  size  and morphology,  so  the  optical properties  enhances with  decreasing  nanoparticles  size.  Moreover  the  direct precipitation technique is a feasible method for production of ZnO nanopowders.

  4. HEXADECAPOLE INTERACTING BOSON APPROXIMATION STRUCTURE FUNCTIONS IN NEODYMIUM ISOTOPES

    NARCIS (Netherlands)

    PERRINO, R; BLASI, N; BORDEWIJK, JA; DELEO, R; HARAKEH, MN; DEJAGER, CW; MICHELETTI, S; PIGNANELLI, M; SANDOR, RKJ; DEVRIES, H; VANDERWERF, SY; WESSELING, J

    1993-01-01

    Low-lying hexadecapole states in stable even-even neodymium isotopes have been investigated by means of inelastic electron scattering. Transition charge densities were extracted in a Fourier-Bessel analysis of the form factors. The analysis of the experimental results within the interacting sdg-boso

  5. Novel 3D nano-antennas of self-assembled zinc oxide on silver nanowires

    Science.gov (United States)

    Sanchez, John Eder

    The manipulation of geometrical and structural arrangement of nano-devices, especially nanoantennas (nantennnas), is highly desirable for a precise controlling and monitoring of the multidirectional radiation pattern generated from the active elements on nanoantenna (nantenna) applications. Here we report the epitaxial growing of ZnO nanorods preferentially oriented along the [0001] direction on pentagonal faces (010) of Ag nanowires (Ag/ZnO ). The Ag/ZnO nanosystem, resembling an hierarchal aerial antenna, was obtained using an innovative microwave irradiation process. There, the combination of chemical synthesis along accelerated micro wave irradiation digestion process, allows us to control precisely the morphology and distribution of the Ag/ZnO nanostructure. Because of the high order arrangement exhibited for the nanosystem as well as high rate of reproducibility in the production process, we opted to tested the nanostructures in a set of experiments ranging from the bulk properties down to in-situ nanoscale; in order to gain valuable information from the experiments and with the aim to give a real application to the nanomaterial. In this order, first, we described the far and near electric field generated for the nantenna obtained from electrical radiation patterns resulting from phase map reconstruction using off-axis electron holography. It is important to notice that knowing the properties at nanoscale level, it will give key insight of mechanism through which the metal-semiconductor (Ag-ZnO) behaves in opto-electronic applications. In fact, using electric numerical approximations methods for a finite number of ZnO nanorods on Ag nanowires it was shown that the electric radiation intensities maps match closely the experimental results obtained with electron holography. Additionally, to reinforce the understanding of how the metal-semiconductor (Ag-ZnO) nanostructures could be used as an active element on photo-signal reception/transmitter generation it was

  6. High critical current density Bi2Sr2CaCu2O x /Ag wire containing oxide precursor synthesized from nano-oxides

    Science.gov (United States)

    Zhang, Yun; Johnson, Stephen; Naderi, Golsa; Chaubal, Manasi; Hunt, Andrew; Schwartz, Justin

    2016-09-01

    Bi2Sr2CaCu2O x (Bi2212)/Ag-alloy wires are manufactured via the oxide-powder-in-tube route by filling Ag/Ag-alloy tubes with Bi2212 oxide precursor, deforming into wire, restacking and heat treating using partial-melt processing (PMP). Recent studies propose several requirements on precursor properties, including stoichiometry, chemical homogeneity, carbon content and phase purity. Here, nanosize oxides produced by nGimat’s proprietary NanoSpray CombustionTM process are used as starting materials to synthesize Bi2212 oxide precursors via solid-state calcination. Oxide powders for wire fill (precursor powder) with precisely controlled stoichiometry and chemical homogeneity containing over 99 vol% of single Bi2212-phase are synthesized. Alkaline-earth cuprate are found to be the only impurity phase in the precursor powders. Phase transformation, carbon release and grain growth during calcination are studied through a series of quench studies. Effects of particle size, surface area, stoichiometry, chemical homogeneity and microstructures of the starting materials on Bi2212 formation and wire transport properties are discussed. Small particle size, high surface area and short diffusion length of the starting materials result in a rapid and homogeneous phase transformation to Bi2212, along with an early and rapid carbon release. The residual carbon in the precursor powder is between 50 and 90 ppm. The strong dependence of transport J c on precursor stoichiometry indicates that compositional variations within precursor powders should be less than 1.5 mol%. Two Bi-rich and Ca-deficient stoichiometries give higher wire transport critical current density, with the highest being 2520 A mm-2 (4.2 K, 5 T) after 1 bar PMP and 4560 A mm-2 (4.2 K, 5 T) after 100 bar overpressure (OP) processing. The low residual carbon content results in smaller and fewer voids within an OP-processed wire filament. Bi-rich and Ca-deficient stoichiometries and small compositional variations

  7. Nano Ru Impregnated Ni-YSZ Anode as Carbon Resistance Layer for Direct Ethanol Solid Oxide Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    SUN; Liangliang; ZHENG; Tao; HU; Zhimin; LUO; Linghong; WU; Yefan; XU; Xu; CHENG; Liang; SHI; Jijun

    2015-01-01

    Carbon formation on conventional Ni and Y2O3 stabilized zirconia(Ni/YSZ) anodes is a major problem for direct ethanol solid oxide fuel cells(DE-SOFC). A nanostructure Ru layer was grown in Ni/YSZ anodes through wet impregnation method with RuC l3 solvent at pH =4. Anode-supported Ni-YSZ/YSZ/(La0.8Sr0.2)0.98 MnO 3±δ(LSM) and Ru-Ni-YSZ/YSZ/LSM fuel cells were compared in terms of the performance and carbon formation with ethanol fuel. X-ray diffraction, scanning electron microscopy, energy disperse spectroscopy and electrochemical workstation were used to study the morphology and fuel cell performance. The results indicate that a nano structured and pearl like Ru layer was well dispersed on the surface of Ni-YSZ materials. The single cell with Ru-impregnated Ni/YSZ showed a maximum power density of 369 m W/cm at 750°C, which was higher than Ni-YSZ/YSZ/LSM. Specifically, no carbon was formed in the anode after 1000 min operation. Fuel cell performance and carbon resistance were enhanced with the addition of the Ru layer.

  8. Conductive polymer/reduced graphene oxide/Au nano particles as efficient composite materials in electrochemical supercapacitors

    Science.gov (United States)

    Shabani Shayeh, J.; Ehsani, A.; Ganjali, M. R.; Norouzi, P.; Jaleh, B.

    2015-10-01

    Polyaniline/reduced graphene oxide/Au nano particles (PANI/rGO/AuNPs) as a hybrid supercapacitor were deposited on a glassy carbon electrode (GCE) by cyclic voltammetry (CV) method as ternary composites and their electrochemical performance was evaluated in acidic medium. Scanning electron micrographs clearly revealed the formation of nanocomposites on the surface of the working electrode. Scanning electron micrographs (SEM) clearly revealed the formation of nanocomposites on the surface of working electrode. Different electrochemical methods including galvanostatic charge-discharge (CD) experiments, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were carried out in order to investigate the applicability of the system as a supercapacitor. Based on the cyclic voltammogram results obtained, PANI/rGO/AuNPs gave higher specific capacitance, power and energy values than PANI at a current density of 1 mA cm-2. Specific capacitance (SC) of PANI and PANI/rGO/AuNPs electrodes calculated using CV method are 190 and 303 F g-1, respectively. The present study introduces new nanocomposite materials for electrochemical redox capacitors with advantages including long life cycle and stability due to synergistic effects of each component.

  9. Conductive polymer/reduced graphene oxide/Au nano particles as efficient composite materials in electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Shabani Shayeh, J. [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Ehsani, A., E-mail: a.ehsani@qom.ac.ir [Department of Chemistry, Faculty of Science, University of Qom, P.O. Box 37185-359, Qom (Iran, Islamic Republic of); Ganjali, M.R.; Norouzi, P. [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Endocrinology & Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Jaleh, B. [Physics Department, Bu-Ali Sina University, Hamedan 65174 (Iran, Islamic Republic of)

    2015-10-30

    Graphical abstract: - Highlights: • PANI/rGO/AuNPs as a ternary composite synthesized by electrodeposition. • Presence of rGO/AuNPs caused increasing the stability of electrodes. • Composite represented high specific capacitance, specific power and specific energy values than PANI. - Abstract: Polyaniline/reduced graphene oxide/Au nano particles (PANI/rGO/AuNPs) as a hybrid supercapacitor were deposited on a glassy carbon electrode (GCE) by cyclic voltammetry (CV) method as ternary composites and their electrochemical performance was evaluated in acidic medium. Scanning electron micrographs clearly revealed the formation of nanocomposites on the surface of the working electrode. Scanning electron micrographs (SEM) clearly revealed the formation of nanocomposites on the surface of working electrode. Different electrochemical methods including galvanostatic charge–discharge (CD) experiments, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were carried out in order to investigate the applicability of the system as a supercapacitor. Based on the cyclic voltammogram results obtained, PANI/rGO/AuNPs gave higher specific capacitance, power and energy values than PANI at a current density of 1 mA cm{sup −2}. Specific capacitance (SC) of PANI and PANI/rGO/AuNPs electrodes calculated using CV method are 190 and 303 F g{sup −1}, respectively. The present study introduces new nanocomposite materials for electrochemical redox capacitors with advantages including long life cycle and stability due to synergistic effects of each component.

  10. Evaluation of Radiation Dose Reduction during CT Scans Using Oxide Bismuth and Nano-Barium Sulfate Shields

    CERN Document Server

    Seoung, Youl-Hun

    2015-01-01

    The purpose of the present study was to evaluate radiation dose reduction and image quality during CT scanning by using a new dose reduction fiber sheet (DRFS) with commercially available bismuth shields. These DRFS were composed of nano-barium sulfate (BaSO4), filling the gaps left by the large oxide bismuth (Bi2O3) particle sizes. The radiation dose was measured five times at directionss of 12 o'clock from the center of the polymethyl methacrylate (PMMA) head phantom to calculate an average value using a CT ionization chamber. The image quality measured CT transverse images of the PMMA head phantom depending on X-ray tube voltages and the type of shielding. Two regions of interest in CT transverse images were chosen from the right and left areas under the surface of the PMMA head phantom and from ion chamber holes located at directions of 12 o'clock from the center of the PMMA head phantom. The results of this study showed that the new DRFS shields could reduce dosages to 15.61%, 23.05%, and 22.71% more in ...

  11. A nanobiosensor composed of Exfoliated Graphene Oxide and Gold Nano-Urchins, for detection of GMO products.

    Science.gov (United States)

    Aghili, Zahra; Nasirizadeh, Navid; Divsalar, Adeleh; Shoeibi, Shahram; Yaghmaei, Parichehreh

    2017-09-15

    Genetically Modified Organisms, have been entered our food chain and detection of these organisms in market products are still the main challenge for scientists. Among several developed detection/quantification methods for detection of these organisms, the electrochemical nanobiosensors are the most attended which are combining the advantages of using nanomaterials, electrochemical methods and biosensors. In this research, a novel and sensitive electrochemical nanobiosensor for detection/quantification of these organisms have been developed using nanomaterials; Exfoliated Graphene Oxide and Gold Nano-Urchins for modification of the screen-printed carbon electrode, and also applying a specific DNA probe as well as hematoxylin for electrochemical indicator. Application time period and concentration of the components have been optimized and also several reliable methods have been used to assess the correct assembling of the nanobiosensor e.g. field emission scanning electron microscope, cyclic voltammetry and electrochemical impedance spectroscopy. The results shown the linear range of the sensor was 40.0-1100.0 femtomolar and the limit of detection calculated as 13.0 femtomolar. Besides, the biosensor had good selectivity towards the target DNA over the non-specific sequences and also it was cost and time-effective and possess ability to be used in real sample environment of extracted DNA of Genetically Modified Organism products. Therefore, the superiority of the aforementioned specification to the other previously published methods was proved adequate. Copyright © 2017. Published by Elsevier B.V.

  12. Contribution of coated humic acids calculated through their surface coverage on nano iron oxides for ofloxacin and norfloxacin sorption.

    Science.gov (United States)

    Peng, Hongbo; Liang, Ni; Li, Hao; Chen, Fangyuan; Zhang, Di; Pan, Bo; Xing, Baoshan

    2015-09-01

    Sorption of organic contaminants on organo-mineral complexes has been investigated extensively, but the sorption contribution of mineral particles was not properly addressed before calculating KOC, especially for ionic organic contaminants. We measured the surface coverage of a humic acid (HA) on nano iron oxides (n-Fe2O3) in a series of synthesized organo-mineral complexes. The contribution of the coated HA to ofloxacin (OFL) and norfloxacin (NOR) sorption in HA-n-Fe2O3 complexes was over 80% of the total sorption with the surface coverage of 36% and fOC of 1.6%. All the coated HA showed higher sorption to NOR and OFL in comparison to the original HA, suggesting HA fractionation and/or physical re-conformation during organo-mineral complex formation. The decreased KOC with multilayer coating may suggest the importance of site-specific interactions for OFL sorption, while the increased KOC with multilayer coating may suggest the importance of partitioning in hydrophobic region for NOR sorption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Nano Ru Impregnated Ni-YSZ Anode as Carbon Resistance Layer for Direct Ethanol Solid Oxide Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    SUN Liangliang; ZHENG Tao; HU Zhimin; LUO Linghong; WU Yefan; XU Xu; CHENG Liang; SHI Jijun

    2015-01-01

    Carbon formation on conventional Ni and Y2O3stabilized zirconia (Ni/YSZ) anodes is a major problem for direct ethanol solid oxide fuel cells (DE-SOFC). A nanostructure Ru layer was grown in Ni/YSZ anodes through wet impregnation method with RuCl3solvent at pH=4. Anode-supported Ni-YSZ/YSZ/(La0.8Sr0.2)0.98MnO3±δ(LSM) and Ru-Ni-YSZ/YSZ/LSM fuel cells were compared in terms of the performance and carbon formation with ethanol fuel. X-ray diffraction, scanning electron microscopy,energy disperse spectroscopy and electrochemical workstation were used to study the morphology and fuel cell performance. The results indicate that a nano structured and pearl like Ru layer was well dispersed on the surface of Ni-YSZ materials. The single cell with Ru-impregnated Ni/YSZ showed a maximum power density of 369 mW/cmat 750°C, which was higher than Ni-YSZ/YSZ/LSM. Specifically, no carbon was formed in the anode after 1000 min operation. Fuel cell performance and carbon resistance were enhanced with the addition of the Ru layer.

  14. The use of visible light and metal oxide nano particles for pathogen inactivation

    Science.gov (United States)

    Lubart, R.; Lipovski, A.; Gedanken, A.

    2012-09-01

    Since the effectiveness of antibiotic treatment is decreasing due to the development of resistant strains, alternative approaches for destroying microorganisms are needed. In this review we summarize new technologies that might be effective for pathogen inactivation. In the past we found that intense blue light could be used for bacterial eradication. The phototoxic effect correlated with the amount of reactive oxygen species (ROS) generated by the bacteria due to illumination. Recently it has been shown that the effect of light can be enhanced by introducing metal oxide nanoparticles (nps) to the bacteria prior to irradiation. This led us to suggest combining nanoparticles with visible light irradiation for pathogen eradication. We have shown that combination of illumination with the nanoparticles (ZnO or TiO2) resulted in a marked increase in the reduction of bacterial viability to a mean reduction of 80-90% for both nanoaprticles. As a matter of fact metal oxide nps alone can be used for bacteria destruction. The advantage of our approach is the use of lower concentrations of nps, combined with reduced light intensity that is less toxic to the host tissue. To further avoid the toxicity of metal oxides nps on healthy tissue it is possible to coat their surfaces with various substrates including ceramics and polymers. Recently Zinc oxide nanoparticles have been synthesized and deposited on the surface of cotton fabrics using ultrasound irradiation. Thus in the future we will try to treat infected wounds with transparent bandages coated with ZnO that will be applied to the wounds prior to irradiation.

  15. Picosecond nonlinear optical properties of cuprous oxide with different nano-morphologies

    Indian Academy of Sciences (India)

    P Harshavardhan Reddy; H Sekhar; D Narayana Rao

    2014-02-01

    Cuprous oxide nanoclusters, microcubes and microparticles were successfully synthesized by a simple co-precipitation method. Phase purity and crystallinity of the samples were studied by using X-ray powder diffraction. Transmission electron microscopy (TEM) images show different morphologies like nanoclusters, microcubes and microparticles. For linear and nonlinear optical measurements, the as-synthesized Cu2O with different morphologies were dispersed in isopropanol solution. The absorption spectrum recorded in the visible regions shows peaks that depend on the morphology of the particles and the peak shifts towards red region as one goes from nanoclusters to microparticles. Simple open-aperture Z-scan technique is used to measure nonlinear optical properties of cuprous oxide at 532 nm, 30 ps excitation at 10 Hz repetition rate. Cuprous oxide nanoclusters show reverse saturable absorption (RSA) behaviour, the microcubes and microparticles at a similar concentration exhibit saturable absorption (SA) type of behaviour at lower peak intensities and exhibit RSA within SA at higher peak intensities. The results show that the transition from SA to RSA can be ascribed to the two-photon absorption (TPA) process.

  16. Size Resolved High Temperature Oxidation Kinetics of Nano-Sized Titanium and Zirconium Particles.

    Science.gov (United States)

    Zong, Yichen; Jacob, Rohit J; Li, Shuiqing; Zachariah, Michael R

    2015-06-18

    While ultrafine metal particles offer the possibility of very high energy density fuels, there is considerable uncertainty in the mechanism by which metal nanoparticles burn, and few studies that have examined the size dependence to their kinetics at the nanoscale. In this work we quantify the size dependence to the burning rate of titanium and zirconium nanoparticles. Nanoparticles in the range of 20-150 nm were produced via pulsed laser ablation, and then in-flight size-selected using differential electrical mobility. The size-selected oxide free metal particles were directly injected into the post flame region of a laminar flame to create a high temperature (1700-2500 K) oxidizing environment. The reaction was monitored using high-speed videography by tracking the emission from individual nanoparticles. We find that sintering occurs prior to significant reaction, and that once sintering is accounted for, the rate of combustion follows a near nearly (diameter)(1) power-law dependence. Additionally, Arrhenius parameters for the combustion of these nanoparticles were evaluated by measuring the burn times at different ambient temperatures. The optical emission from combustion was also used to model the oxidation process, which we find can be reasonably described with a kinetically controlled shrinking core model.

  17. Size dependent microbial oxidation and reduction of magnetite nano- and micro-particles

    Science.gov (United States)

    Byrne, James M.; van der Laan, Gerrit; Figueroa, Adriana I.; Qafoku, Odeta; Wang, Chongmin; Pearce, Carolyn I.; Jackson, Michael; Feinberg, Joshua; Rosso, Kevin M.; Kappler, Andreas

    2016-08-01

    The ability for magnetite to act as a recyclable electron donor and acceptor for Fe-metabolizing bacteria has recently been shown. However, it remains poorly understood whether microbe-mineral interfacial electron transfer processes are limited by the redox capacity of the magnetite surface or that of whole particles. Here we examine this issue for the phototrophic Fe(II)-oxidizing bacteria Rhodopseudomonas palustris TIE-1 and the Fe(III)-reducing bacteria Geobacter sulfurreducens, comparing magnetite nanoparticles (d ≈ 12 nm) against microparticles (d ≈ 100-200 nm). By integrating surface-sensitive and bulk-sensitive measurement techniques we observed a particle surface that was enriched in Fe(II) with respect to a more oxidized core. This enables microbial Fe(II) oxidation to occur relatively easily at the surface of the mineral suggesting that the electron transfer is dependent upon particle size. However, microbial Fe(III) reduction proceeds via conduction of electrons into the particle interior, i.e. it can be considered as more of a bulk electron transfer process that is independent of particle size. The finding has potential implications on the ability of magnetite to be used for long range electron transport in soils and sediments.

  18. Nano-Structured Magnesium Oxide Coated Iron Ore: Its Application to the Remediation of Wastewater Containing Lead.

    Science.gov (United States)

    Nagarajah, Ranjini; Jang, Min; Pichiah, Saravanan; Cho, Jongman; Snyder, Shane A

    2015-12-01

    Magnetically separable nano-structured magnesium oxide coated iron ore (IO(MgO)) was prepared using environmentally benign chemicals, such as iron ore (IO), magnesium(II) nitrate hexahydrate [Mg(NO3)2 x 6H2O] and urea; via an easy and fast preparation method. The lO(MgO) was characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) and alternating gradient magnetometer (AGM) analyses. The isotherm and kinetic studies indicated that lO(MgO) has a comparably higher Langmuir constant (K(L), 1.69 L mg(-1)) and maximum sorption capacity (33.9 mg g(-1)) for lead (Pb) than other inorganic media. Based on MgO amount, the removal capacity of Pb by IO(MgO) was 2,724 mg Pb (g MgO)(-1), which was higher than that (1,980 mg g(-1)) for flowerlike magnesium oxide nanostructures reported by Cao et al. The kinetics, FE-SEM, elemental mapping and XRD results revealed that the substitution followed by precipitation was identified as the mechanism of Pb removal and plumbophyllite (Pb2Si4O10 x H2O) was the precipitated phase of Pb. A leaching test revealed that IOMgO) had negligible concentrations of leached Fe at pH 4-9. Since the base material, IO, is cheap and easily available, lO(MgO) could be produced in massive amounts and used for remediation of wastewater containing heavy metals, applying simple and fast magnetic separation.

  19. Selected Fe and Mn (nano)oxides as perspective amendments for the stabilization of As in contaminated soils.

    Science.gov (United States)

    Michálková, Zuzana; Komárek, Michael; Veselská, Veronika; Číhalová, Sylva

    2016-06-01

    An amorphous Mn oxide (AMO), nanomaghemite, and nanomagnetite were used as potential amendments reducing the mobility of As in three contrasting contaminated soils differing in origin of As contamination. Adsorption experiments and XPS analyses combined with incubation batch experiments and pH-static leaching tests were used. The AMO showed excellent adsorption capacity for As(V) reaching a maximum of 1.79 mmol g(-1) at pH 7 and 8. Interestingly, the adsorption capacity in this case decreases with decreasing pH, probably as a result of AMO dissolution at lower pH values. Chemical sorption of As(V) onto AMO was further confirmed with XPS. Both Fe nano-oxides proved the highest adsorption capacity at pH 4 reaching 11 mg g(-1) of adsorbed As(V). The AMO was also the most efficient amendment for decreasing As concentrations in soil solutions during 8 weeks of incubation. Additionally, pH-static leaching tests were performed at pH 4, 5, 6, 7, and natural pH (not adjusted) and AMO again proved the highest ability to decrease As content in leachate. On the other hand, strong dissolution of this amendment at lower pH values (especially pH 4) was observed. For that reason, AMO appears as a promising stabilizing agent for As, especially in neutral, alkaline, or slightly acidic soils, where As(V) species are expected to be more mobile.

  20. Oxide-Free Bonding of III-V-Based Material on Silicon and Nano-Structuration of the Hybrid Waveguide for Advanced Optical Functions

    Directory of Open Access Journals (Sweden)

    Konstantinos Pantzas

    2015-10-01

    Full Text Available Oxide-free bonding of III-V-based materials for integrated optics is demonstrated on both planar Silicon (Si surfaces and nanostructured ones, using Silicon on Isolator (SOI or Si substrates. The hybrid interface is characterized electrically and mechanically. A hybrid InP-on-SOI waveguide, including a bi-periodic nano structuration of the silicon guiding layer is demonstrated to provide wavelength selective transmission. Such an oxide-free interface associated with the nanostructured design of the guiding geometry has great potential for both electrical and optical operation of improved hybrid devices.

  1. Nano CMOS

    Directory of Open Access Journals (Sweden)

    Malay Ranjan Tripathy

    2009-05-01

    Full Text Available Complementary metal-oxide-semiconductor (CMOS has become major challenge to scaling and integration. However, innovation in transistor structures and integration of novel materials are needed to sustain this performance trend. CMOS variability in the scaling technology becoming very important concern because of limitation of process control over statistical variability related to the fundamental discreteness of charge and matter. Different aspects responsible for device variability are discussed in this article. The challenges and opportunities of nano CMOS technology are outlined here.

  2. The flame retardant properties of nano magnesium oxide on wood%纳米氧化镁对木材的阻燃特性

    Institute of Scientific and Technical Information of China (English)

    云维采; 纪全; 谭利文; 宗鲁; 夏延致

    2015-01-01

    将纳米氧化镁作为阻燃剂利用物理机械混合的方法加入到木粉中,经极限氧指数( LOI )、锥形量热仪( CONE)测试结果表明,纳米氧化镁能显著提高木制品的氧指数,燃烧过程中的热释放速率、热释放量、烟产生速率、总生烟量和CO产率明显降低,具有很好的阻燃效果。经计算纳米氧化镁的加入能够提高样品的残炭率,残炭率提高10%左右。其阻燃机理一方面是由于纳米氧化镁可以作为物理屏障层,起到耐高温绝热和隔绝氧气的作用;另一方面,纳米氧化镁会参与木材的燃烧,改变木材的裂解途径,残留有更多的不可燃物质。%Nano magnesium oxide as flame retardant was added into wood powder by mechanical mixing, and the samples were tested by the limiting oxygen index(LOI),cone calorimeter(CONE). The test re-sults showed that nano magnesium oxide could improve the oxygen index of wood products. Meanwhile, heat release rate,total heat release,smoke production rate,total smoke rate and the yield of CO decreased obviously,and the samples had good flame retardant effect. The calculation of carbon residue ratio showed that adding nano magnesium oxide could improve the residual carbon sample ratio, which increased by 10%. The flame retardant mechanism, on the one hand, the nano magnesium oxide serve as a physical barrier layer,have a high temperature resistant and insulating effect and isolate the wood from oxygen;On the other hand,nano magnesium oxide can participate in the combustion of wood,change the wood pyroly-sis pathway and leave more flammable materials.

  3. Reduction of interpore distance of anodized aluminum oxide nano pattern by mixed H3PO4:H2SO4 electrolyte.

    Science.gov (United States)

    Song, Kwang Min; Park, Joonmo; Ryu, Sang-Wan

    2007-11-01

    A self-formed and ordered anodized aluminum oxide (AAO) nano pattern has generated considerable interest in both scientific research and commercial application. However, the interpore distance obtainable by AAO is limited by 40-500 nm depending on electrolyte and anodizing voltage. It's believed that below-30 nm AAO pattern is a key technology in the fabrication semiconductor nano structures with enhanced quantum confinement effect, so we worked on the reduction of interpore distance of AAO with a novel electrolyte. AAO nano patterns were fabricated with mixed H2SO4 and H3PO4 as an electrolyte for various voltages and temperatures. The interpore distance and pore diameter of AAO were decreased with reduced anodizing voltage. As a result, an AAO nano pattern with the interpore distance of 27 nm and the pore diameter of 7 nm was obtained. This is the smallest pattern, as long as we know, reported till now with AAO technique. The fabricated AAO pattern could be utilized for uniform and high density quantum dots with increased quantum effect.

  4. Chemical Synthesis of Nano-Sized particles of Lead Oxide and their Characterization Studies

    CERN Document Server

    Alagar, M; Raja, A Kubera; 10.3923/jas.2012.398.401

    2012-01-01

    The quantum dots of semiconductor display novel and interesting phenomena that have not been in the bulk material. The color tunability is one of the most attractive characteristics in II-VI semiconductor nanoparticles such as CdS, ZnS, CdSe, ZnSe and PbO. In this work, the semiconductor lead oxide nanoparticles are prepared by chemical method. The average particle size, specific surface area, crystallinity index are estimated from XRD analysis. The structural, functional groups and optical characters are analyzed with using of SEM, FTIR and UV- Visible techniques. The optical band gap value has also been determined.

  5. The Development of Nano-Composite Electrodes for Solid Oxide Electrolyzers

    Energy Technology Data Exchange (ETDEWEB)

    Gorte, Raymond J.; Vohs, John M.

    2014-03-26

    Solid oxide fuel cells (SOFC) and electrolyzers (SOE) offer an attractive means for converting between electrical and chemical energy. Because they operate at high temperatures and are usually based on electrolytes that are oxygen-ion conducting ceramics, such as yttria-stabilized zirconia (YSZ), they are equally capable of converting between CO and CO2 as between H2 and H2O. When operated in the SOFC mode, they are able to operate on hydrocarbon fuels so long as there are no materials within the anode that can catalyze carbon formation. Compared to other types of electrolyzers, SOE can exhibit the highest efficiencies because the theoretical Nernst potential is lower at high temperatures and because the electrode overpotentials in SOE tend to be much lower. Finally, pure H2 can be produced without an external electrical source by electrolysis of steam at one electrode and oxidation of any fuel at the other electrode through a process known as Natural-Gas Assisted Steam Electrolysis. This final report describes results from studies of novel electrodes for SOE and SOFC prepared by infiltration methods.

  6. Nano-vanadium oxide thin films in mixed phase for microbolometer applications

    Energy Technology Data Exchange (ETDEWEB)

    Subrahmanyam, A; Bharat Kumar Reddy, Y [Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Nagendra, C L [LEOS, ISRO, Peenya Industrial Estate, Bangalore 560060 (India)], E-mail: manu@iitm.ac.in

    2008-10-07

    Among the several phases of vanadium oxide, mixed phases of VO{sub 2} and V{sub 2}O{sub 5} are preferred for uncooled micro-bolometers with low noise. The aim of this investigation is to achieve mixed phase VO{sub 2} and V{sub 2}O{sub 5} thin films with nanometre grain sizes and high temperature coefficient of resistance (TCR). Since the phase depends upon the oxygen reactivity, these vanadium oxide thin films are prepared by reactive electron beam evaporation at different oxygen flow rates and substrate temperatures. The mixed phases have been evaluated through x-ray diffraction and x-ray photo emission studies. The temperature dependence of resistance has shown that the films grown at 473 K with 2.8 x 10{sup -5} mbar chamber pressure of oxygen (VO{sub 2} : V{sub 2}O{sub 5} ratio of 36 : 64) have the highest TCR of -3.2 K{sup -1} with a reasonable low resistance (120 {omega}/square)

  7. A simple granulation technique for preparing high-porosity nano copper oxide(Ⅱ) catalyst beads

    Institute of Scientific and Technical Information of China (English)

    Seyed Javad Ahmadia; Mohammad Outokesh; Morteza Hosseinpour; Tahereh Mousavand

    2011-01-01

    A simple and efficient method was developed for fabricating spherical granules of CuO catalyst via a three-step procedure.In the first step,copper oxide nanoparticles were synthesized by hydrothermal decomposition of copper nitrate solution under supercritical condition.Then,they were immobilized in the polymeric matrix of calcium alginate,and followed by high-temperature calcination in an air stream as the third step,in which carbonaceous materials were oxidized,to result in a pebble-type catalyst of high porosity.The produced CuO nanoparticles were characterized by transmission electron microscopy (TEM) that revealed an average size of 5 nm,X-ray diffractometry (XRD),and thermo gravimetric (TG)analysis.The catalysts were further investigated by BET test for measurement of their surface area,and by temperature-programmed reduction analysis (H2-TPR) for determination of catalytic activity.The results demonstrated that immobilization of the CuO nanoparticle in the polymeric matrix of calcium alginate,followed by calcination at elevated temperatures,could result in notable mechanical strength and enhanced catalytic activity due to preservation of the high surface area,both valuable for practical applications.

  8. Synthesis of nano-sized perovskite-type oxide with the use of polyvinyl pyrrolidone

    Directory of Open Access Journals (Sweden)

    Tsukasa Nagai

    2014-12-01

    Full Text Available A new easy-to-use process for obtaining fine powders of lanthanum-based perovskite-type oxides (La1−xAexMO3: Ae = Ca, Sr, M = Mn, Co, Fe with a high specific surface area was successfully developed by the use of polyvinyl pyrrolidone (PVP as a dispersant. This approach made it possible to prepare a single phase of perovskite by calcining at a lower temperature (600 °C compared to conventional synthetic processes such as a solid state reaction and citrate process. SEM observations revealed that the oxide prepared with PVP was ca. 20–30 nm in size, while those prepared by the citrate process and solid state reaction were ca. 50 nm and 1 μm, respectively. Furthermore, the results of a thermal analysis in which we heated the precursors for the different reactions support the idea that PVP plays an important role in the formation of the perovskite phase at low temperature.

  9. Temperature characterization of dielectric permittivity and AC conductivity of nano copper oxide-doped polyaniline composite

    Science.gov (United States)

    Shubha, L. N.; Madhusudana Rao, P.

    2016-06-01

    The polyaniline/copper oxide (PANI/CuO) nanocomposite was prepared by mixing solutions of polyaniline and copper oxide nanoparticles in dimethyl sulfoxide (DMSO). The synthesized polymer nanocomposites were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and UV-visible spectroscopy. The characteristic peaks in XRD and UV-visible spectra confirmed the presence of CuO in the polymer structure. SEM images indicated morphological changes in the composite matrix as compared to the pristine PANI. The DC conductivity measurements were performed using two-probe method for various temperatures. AC conductivity and dielectric response of the composites were investigated in the frequency range of 102-106Hz using LCR meter. Dielectric permittivity ɛ‧(w) and dielectric loss factor ɛ‧‧(w) were investigated. It was observed that ɛ‧(w) and ɛ‧‧(w) decrease with increase in frequency at all temperatures. At a particular frequency it is observed that both ɛ‧(w) and ɛ‧‧(w) increase with increase in temperature. It was also observed that AC conductivity increased with increase in frequency and temperature.

  10. Oxidative stress and genotoxicity of an organic and an inorganic nanomaterial to Eisenia andrei: SDS/DDAB nano-vesicles and titanium silicon oxide.

    Science.gov (United States)

    Correia, Bruno; Lourenço, Joana; Marques, Sérgio; Nogueira, Verónica; Gavina, Ana; da Graça Rasteiro, Maria; Antunes, Filipe; Mendo, Sónia; Pereira, Ruth

    2017-06-01

    In the past few years the number of studies on the toxic effects of nanomaterials (NMs) in the environment increased significantly. Nonetheless, the data is still scarce, since there is a large number of NMs and new ones are being developed each day. Soils are extremely important for life, and are easily exposed to the released NMs, thus enhanced efforts are needed to study the impacts on soil biota. The objective of the present work was to determine if different concentrations of two NMs, one inorganic (TiSiO4) and other organic (nano-vesicles of sodium sodecyl sulfate/ didodecyl dimethylammonium bromide - SDS/DDAB), are genotoxic to soil invertebrates. Additionally, it was intended to understand whether, in the event of occurring, genotoxicity was caused by the incapability of the cells to deal with the oxidative stress caused by these NMs. With that purpose, Eisenia andrei were exposed for 30 days to the artificial OECD soil contaminated with different concentrations of the NMs being tested. After the exposure, coelomocytes were extracted from earthworms and DNA damage was measured by the comet assay. The activity of antioxidant enzymes (e.g. glutathione peroxidase, glutathione reductase and glutathione-S-Transferase) and lipid peroxidation were also assessed. The results showed that both NMs were genotoxic, particularly TiSiO4 for which significant DNA damages were recorded for concentrations above 444mg of TiSiO4-NM/kg of soildw. Since no statistically significant differences were found in the tested antioxidant enzymes and in lipid peroxidation, the mechanism of genotoxicity of these NMs seemed to be unrelated with oxidative stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Dimensionality aspects of nano micro integrated metal oxide based early stage leak detection room temperature hydrogen sensor

    Science.gov (United States)

    Deshpande, Sameer Arun

    .). Highly porous SnO2 nanoparticles thin film (synthesized using template assisted) showed response time of about 25 seconds and sensitivity 4. The one dimensional tin oxide nanostructures (nanowires) based sensor showed a sensitivity of 4 and response time of 20 sec. Effect of aspect ratio of the nanowires on diffusion of hydrogen molecules in the tin oxide nanowires, effect of catalyst adsorption on nanowire surface and corresponding effect on sensor properties has been studied in detail. Nanotubes of TiO2 prepared using hydrothermal synthesis showed a sensitivity 30 with response time as low as 20 seconds where as, TiO 2 nanotubes synthesized using anodization showed poor sensitivity. The difference is mainly attributed to the issues related to integration of the anodized nanotubes with the MEMS devices. The effect of MEMS device architecture modulation, such as, finger spacing, number and length of fingers and electrode materials were studied. It has been found that faster sensor response (˜ 10 sec) was observed for smaller finger spacing. A diffusion model is proposed for elucidating the effect of inter-electrode distance variation on conductance change of a nano-micro integrated hydrogen sensor for room temperature operation. Both theoretical and experimental results showed a faster response upon exposure to hydrogen when sensor electrode gap was smaller. Also, a linear increase in the sensor sensitivity from 500 to 80000 was observed on increasing the electrode spacing from 2 to 20 mum. The improvement in sensitivity is attributed to the higher reactive sites available for the gaseous species to react on the sensor surface. This phenomenon also correlated to surface adsorbed oxygen vacancies (O-) and the rate of change of surface adsorbed oxygen vacancies. This dissertation studied in detail dimensionality aspects of materials as well as device in detecting hydrogen at room temperature.

  12. The piezoelectric effect on zinc oxide nano on polyimide substrate by spray pyrolysis

    Science.gov (United States)

    Idris, A. A. M.; Arsat, R.; Ahmad, M. K.

    2017-03-01

    This paper reports the effect of the deposition conditions crystal quality and film thickness of the Zinc Oxide (ZnO) film on the polyimide substrate. The ZnO film has been deposited by using the spray pyrolysis technique. This technique needs Zinc Nitrate Hexahydrate with the mixture of deionized water. At 350 °C, a higher c-axis preferred orientation at peak 0002 crystal orientation, which is critical for piezoelectric applications in ZnO thin films are obtained with the thickness of thin film is 300ηm. It also produces the 204.8 Hz of frequency which is higher than other frequency obtained by lower growth temperature.

  13. Toughened and machinable glass matrix composites reinforced with graphene and graphene-oxide nano platelets

    Directory of Open Access Journals (Sweden)

    Harshit Porwal, Peter Tatarko, Salvatore Grasso, Chunfeng Hu, Aldo R Boccaccini, Ivo Dlouhý and Mike J Reece

    2013-01-01

    Full Text Available The processing conditions for preparing well dispersed silica–graphene nanoplatelets and silica–graphene oxide nanoplatelets (GONP composites were optimized using powder and colloidal processing routes. Fully dense silica–GONP composites with up to 2.5 vol% loading were consolidated using spark plasma sintering. The GONP aligned perpendicularly to the applied pressure during sintering. The fracture toughness of the composites increased linearly with increasing concentration of GONP and reached a value of ~0.9 MPa m1/2 for 2.5 vol% loading. Various toughening mechanisms including GONP necking, GONP pull-out, crack bridging, crack deflection and crack branching were observed. GONP decreased the hardness and brittleness index (BI of the composites by ~30 and ~50% respectively. The decrease in BI makes silica–GONP composites machinable compared to pure silica. When compared to silica–Carbon nanotube composites, silica–GONP composites show better process-ability and enhanced mechanical properties.

  14. Improving fiber/matrix interfacial strength through graphene and graphene-oxide nano platelets

    Science.gov (United States)

    Pegoretti, A.; Mahmood, H.; Pedrazzoli, D.; Kalaitzidou, K.

    2016-07-01

    Fiber/matrix interfacial shear strength (ISS) is a key factor determining the mechanical properties of structural composites. In this manuscript the positive effects of both graphene and graphene oxide in improving the ISS value of glass-fiber reinforced composites are experimentally demostrated. Two strategies will be presented: i) uniform dispersion of the nanofillers in the polymer matrix or ii) selective deposition of the nanofillers at the fiber/matrix interface. Both thermoplastic (polypropylene) and thermosetting (epoxy) matrices are investigated and the effects of nanoparticles on the fiber/matrix interface are determined through micromechanical tests on single-fiber composites. Finally, the beneficial effects of the investigated nanofillers on both mechanical and functional (strain monitoring) properties of multiscale macrocomposites are experimentally proved for the cases of polypropylene-based composites reinforced with short glass fibers and on epoxy-based composites reinforced with continuous unidirectional glass fibers.

  15. Particle Surface Softening as Universal Behaviour during Flash Sintering of Oxide Nano-Powders

    Directory of Open Access Journals (Sweden)

    Rachman Chaim

    2017-02-01

    Full Text Available The dissipated electric power in oxide powder compacts, subjected to flash sintering, is several hundreds of W·cm−3. This power is analyzed considering local softening/melting and transient plasma/liquid formation at the particle contacts due to thermal runaway. The sudden increase in compact electric conductivity and dissipated power referred to current percolation through the softening/liquid formed at the particle contacts, at the percolation threshold. The energy-balance and heat transfer considerations during the transient flash event are consistent with the local heating of the nanoparticle contacts to the ceramic melting temperature, or above it. The formation of the plasma by field emission of electrons is also considered.

  16. Light extraction efficiency enhancement in light-emitting diodes with indium tin oxide nano-craters

    Institute of Scientific and Technical Information of China (English)

    Zheng Huaiwen; Zhang Yiyun; Yang Hua; Xue Bin; Wu Kui; Li Jing; Wang Guohong

    2012-01-01

    A simple and low cost method is described which improves extraction efficiency.The indium tin oxide (ITO) textured film was fabricated by using the self-assembly method and dry-etching.The surface morphologies and surface roughness were observed by using an atomic force microscope.The Ⅰ-Ⅴ characteristics,output power and polar radiation pattern of the LEDs with and without textured ITO were measured for comparison.Cylinders and craters were formed on the ITO surface after the etching,the height of which increased with etching time.The output power of the devices is proportional to the etching time.Total internal reflection of light on the ITO-GaN interface is reduced due to the appearance of cylinders and craters,and their increasing height.Thus,the output power is improved.

  17. Copper oxide nano-fluid stabilized by ionic liquid for enhancing thermal conductivity of reservoir formation: Applicable for thermal Enhanced Oil Recovery processes

    Directory of Open Access Journals (Sweden)

    Barahoei M.

    2016-01-01

    Full Text Available Since the oil reservoirs are limited and energy demand is increasing, seeking for high efficient EOR processes or enhancing the efficiency of current proposed EOR methods for producing trapped oil from reservoirs are highly investigated. As a way out, it is possible to couple the EOR and nanotechnology to utilize the efficiency of both methods together. Regarding this possibility, in the current study, in the first stage of investigation stable and uniform water-based solution of nano size particles of copper oxide with different concentrations (0.01-0.05 M were prepared and then injected into the core samples. In the first stage, the effects of different surfactants respect to their concentrations was investigated. Then, different scenarios of using nano-fluid as a thermal conductivity modifier were examined. The obtained results clearly demonstrate that changing concentration of nano particles of copper oxide from 0.01 M to 0.05 M is able to enhance the thermal conductivity of rocks from 27 % to 48 % compared with the thermal conductivity of dry core.

  18. The Effect of Precursor Ligands and Oxidation State in the Synthesis of Bimetallic Nano-Alloys

    KAUST Repository

    LaGrow, Alec P.

    2015-05-12

    The characteristics of bimetallic nanomaterials are dictated by their size, shape and elemental distribution. Solution synthesis is widely utilized to form nanomaterials, such as nanoparticles, with controlled size and shape. However, the effects of variables on the characteristics of bimetallic nanomaterials are not completely understood. In this study, we used a continuous-flow synthetic strategy to explore the effects of the ligands and the oxidation state of a metal precursor in a shape-controlled synthesis on the final shape of the nanomaterials and the elemental distribution within the alloy. We demonstrate that this strategy can tune the size of monodisperse PtM (M=Ni or Cu) alloy nanocrystals ranging from 3 to 16 nm with an octahedral shape using acetylacetonate or halide precursors of Pt(II), Pt(IV) and Ni or Cu (II). The nanoparticles formed from halide precursors showed an enrichment of platinum on their surfaces, and the bromides could oxidatively etch the nanoparticles during synthesis with the O2/Br- pair. The two nanocrystal precursors can be uti-lized independently and can control the size with a trend of Pt(acac)2

  19. Microwave-Assisted Combustion Synthesis of Nano Iron Oxide/Iron-Coated Activated Carbon, Anthracite, Cellulose Fiber, and Silica, with Arsenic Adsorption Studies

    Directory of Open Access Journals (Sweden)

    Mallikarjuna N. Nadagouda

    2011-01-01

    Full Text Available Combustion synthesis of iron oxide/iron coated carbons such as activated carbon, anthracite, cellulose fiber, and silica is described. The reactions were carried out in alumina crucibles using a Panasonic kitchen microwave with inverter technology, and the reaction process was completed within a few minutes. The method used no additional fuel and nitrate, which is present in the precursor itself, to drive the reaction. The obtained samples were then characterized with X-ray mapping, scanning electron microscopy (SEM, energy dispersive X-ray analysis (EDS, selected area diffraction pattern (SAED, transmission electron microscopy (TEM, X-ray diffraction (XRD, and inductively coupled plasma (ICP spectroscopy. The size of the iron oxide/iron nanoparticle-coated activated carbon, anthracite, cellulose fiber, and silica samples were found to be in the nano range (50–400 nm. The iron oxide/iron nanoparticles mostly crystallized into cubic symmetry which was confirmed by SAED. The XRD pattern indicated that iron oxide/iron nano particles existed in four major phases. That is, γ-Fe2O3, α-Fe2O3, Fe3O4, and Fe. These iron-coated activated carbon, anthracite, cellulose fiber, and silica samples were tested for arsenic adsorption through batch experiments, revealing that few samples had significant arsenic adsorption.

  20. A facile approach to prepare silicon-based Pt-Ag tubular dendritic nano-forests (tDNFs) for solar-light-enhanced methanol oxidation reaction

    Science.gov (United States)

    Lin, Chun-Ting; Shiao, Ming-Hua; Chang, Mao-Nan; Chu, Nancy; Chen, Yu-Wei; Peng, Yu-Hsuan; Liao, Bo-Huei; Huang, Hung Ji; Hsiao, Chien-Nan; Tseng, Fan-Gang

    2015-02-01

    In this paper, a facile two-step Galvanic replacement reaction (GRR) is proposed to prepare Pt-Ag tubular dendritic nano-forests (tDNFs) in ambient condition for enhancing methanol oxidation reaction (MOR) under solar illumination. In the first GRR, a homogeneous layer of silver dendritic nano-forests (DNFs) with 10 μm in thickness was grown on Si wafer in 5 min in silver nitride (AgNO3) and buffer oxide etchant (BOE) solution. In the second GRR, we utilized chloroplatinic acid (H2PtCl6) as the precursor for platinum (Pt) deposition to further transform the prepared Ag DNFs into Pt-Ag tDNFs. The catalytic performance and solar response of the Pt-Ag tDNFs toward methanol electro-oxidation are also studied by cyclic voltammetry (CV) and chronoamperometry (CA). The methanol oxidation current was boosted by 6.4% under solar illumination on the Pt-Ag tDNFs due to the induced localized surface plasmon resonance (LSPR) on the dendritic structure. Current results provide a cost-effective and facile approach to prepare solar-driven metallic electrodes potentially applicable to photo-electro-chemical fuel cells.

  1. Nano-crystals of cerium–hafnium binary oxide: Their size-dependent structure

    Energy Technology Data Exchange (ETDEWEB)

    Raitano, Joan M. [Department of Applied Physics and Applied Mathematics, Materials Science and Engineering Program, Columbia University, New York, NY 10027 (United States); Khalid, Syed [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973 (United States); Marinkovic, Nebojsa [Chemical Engineering Department, Columbia University, 500 W 120th St, Mudd 801, New York, NY 10027 (United States); Chan, Siu-Wai, E-mail: sc174@columbia.edu [Department of Applied Physics and Applied Mathematics, Materials Science and Engineering Program, Columbia University, New York, NY 10027 (United States)

    2015-09-25

    Highlights: • (1 − x)CeO{sub 2}–xHfO{sub 2} was precipitated (0 < x < 1) and calcined in air. • For x ⩽ 0.14, crystallites ⩽140 nm in size exhibit only the fluorite structure. • This low hafnia solubility is attributable to no auto-reduction (Ce{sup 3+} = 0). • The low solubility is also due to the high temperature required for homogenization. • Coarsening is lessened as Hf{sup 4+} ions slow cation diffusion in these crystallites. - Abstract: Cerium oxide (CeO{sub 2}, “ceria”) and hafnium oxide (HfO{sub 2}, “hafnia”) were aqueously co-precipitated and subsequently calcined to allow for homogenization. The size of the (1−x)CeO{sub 2}–xHfO{sub 2} crystallites, determined by the Scherrer equation, varied from 140 nm for x = 0 to 15 nm for x = 0.73. For x ⩽ 0.14, only cubic structures are visible in X-ray diffractograms, and the lattice parameters are consistent with the values expected for structurally cubic solid solutions of hafnia in ceria. At x = 0.26, tetragonal and monoclinic phases nucleated with the former not being observed in the bulk phase diagram for ceria–hafnia. Therefore, the solubility limit of the cubic structure is between x = 0.14 and x = 0.26 for 40–61 nm crystallites, the sizes of these respective compositions. More specifically, for the 40 nm crystallites of x = 0.26 (1 − x)CeO{sub 2}–xHfO{sub 2}, 15% of the hafnia remains in a structurally cubic solid solution with ceria based on the observed cubic lattice parameter. The compositional domain for the cubic fluorite structure in this study is narrower than other nanostructured (1 − x)CeO{sub 2}–xHfO{sub 2} studies, especially studies with crystallite sizes less than 10 nm, but wider than observed in the bulk and helps to expand the size regime over which the relationship between crystallite size and phase stability is known. The extent of this cubic-structure domain is mainly attributable to the intermediate crystallite size and the roughly zero Ce{sup 3

  2. Co-precipitation synthesis of nano-composites consists of zinc and tin oxides coatings on glass with enhanced photocatalytic activity on degradation of Reactive Blue 160 KE2B.

    Science.gov (United States)

    Habibi, Mohammad Hossein; Mardani, Maryam

    2015-02-25

    Nano-composite containing zinc oxide-tin oxide was obtained by a facile co-precipitation route using tin chloride tetrahydrate and zinc chloride as precursors and coated on glass by Doctor Blade deposition. The crystalline structure and morphology of composites were evaluated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The XRD results showed peaks relative to zinc oxide with hexagonal wurtzite structure and tin oxide with tetragonal structure. FESEM observations showed that the nano-composite consisted of aggregates of particles with an average particle size of 18 nm. The photocatalytic activity of the pure SnO2, pure ZnO, ZnSnO3-Zn2SnO4 and ZnO-SnO2 nano-structure thin films was examined using the degradation of a textile dye Reactive Blue 160 (KE2B). ZnO-SnO2 nano-composite showed enhanced photo-catalytic activity than the pure zinc oxide and tin oxide. The enhanced photo-catalytic activity of the nano-composite was ascribed to an improved charge separation of the photo-generated electron-hole pairs.

  3. Surface Coating of Oxide Powders: A New Synthesis Method to Process Biomedical Grade Nano-Composites

    Directory of Open Access Journals (Sweden)

    Paola Palmero

    2014-07-01

    Full Text Available Composite and nanocomposite ceramics have achieved special interest in recent years when used for biomedical applications. They have demonstrated, in some cases, increased performance, reliability, and stability in vivo, with respect to pure monolithic ceramics. Current research aims at developing new compositions and architectures to further increase their properties. However, the ability to tailor the microstructure requires the careful control of all steps of manufacturing, from the synthesis of composite nanopowders, to their processing and sintering. This review aims at deepening understanding of the critical issues associated with the manufacturing of nanocomposite ceramics, focusing on the key role of the synthesis methods to develop homogeneous and tailored microstructures. In this frame, the authors have developed an innovative method, named “surface-coating process”, in which matrix oxide powders are coated with inorganic precursors of the second phase. The method is illustrated into two case studies; the former, on Zirconia Toughened Alumina (ZTA materials for orthopedic applications, and the latter, on Zirconia-based composites for dental implants, discussing the advances and the potential of the method, which can become a valuable alternative to the current synthesis process already used at a clinical and industrial scale.

  4. Nano-bio compatibility of PEGylated reduced graphene oxide on mesenchymal stem cells

    Science.gov (United States)

    Syama, S.; Aby, C. P.; Maekawa, Toru; Sakthikumar, D.; Mohanan, P. V.

    2017-06-01

    Graphene, with its unique physico-chemical properties, has found widespread biomedical application. It is used as a carrier for drug or gene delivery, photothermal therapy, bioimaging, in antibacterial agents and for the development of biosensors. Besides this, graphene has the scope to be used for wound healing, tissue engineering and regenerative medicine. In the present study, polyethylene-glycol-(PEG)ylated reduced graphene oxide (PrGO) was synthesized, characterized, and its interaction with mouse bone marrow mesenchymal stem cells (MSCs) was studied. in vitro cytotoxicity and differentiation study showed PrGO neither induced toxicity nor impaired the differentiation potential of the stem cells. PrGO was effectively internalized by MSCs and distributed throughout the cytoplasm. None of the PrGO was seen in the nucleus. Although it seems to induce increased reactive oxygen species (ROS) production inside the cell, no change in cell proliferation or cellular function was observed. Hence it is recommended that the synthesized PrGO is applicable for tissue engineering, and can also be used as a substrate platform for stem cell culture and differentiation.

  5. Exploration of alginate hydrogel/nano zinc oxide composite bandages for infected wounds

    Directory of Open Access Journals (Sweden)

    Mohandas A

    2015-10-01

    Full Text Available Annapoorna Mohandas,* Sudheesh Kumar PT,* Biswas Raja, Vinoth-Kumar Lakshmanan, Rangasamy Jayakumar Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, India *These authors contributed equally to this work Abstract: Alginate hydrogel/zinc oxide nanoparticles (nZnO composite bandage was developed by freeze-dry method from the mixture of nZnO and alginate hydrogel. The developed composite bandage was porous with porosity at a range of 60%–70%. The swelling ratios of the bandages decreased with increasing concentrations of nZnO. The composite bandages with nZnO incorporation showed controlled degradation profile and faster blood clotting ability when compared to the KALTOSTAT® and control bandages without nZnO. The prepared composite bandages exhibited excellent antimicrobial activity against Escherichia coli, Staphylococcus aureus, Candida albicans, and methicillin resistant S. aureus (MRSA. Cytocompatibility evaluation of the prepared composite bandages done on human dermal fibroblast cells by Alamar assay and infiltration studies proved that the bandages have a non-toxic nature at lower concentrations of nZnO whereas slight reduction in viability was seen with increasing nZnO concentrations. The qualitative analysis of ex-vivo re-epithelialization on porcine skin revealed keratinocyte infiltration toward wound area for nZnO alginate bandages. Keywords: alginate, hydrogel, ZnO nanoparticle, hemostatic, antimicrobial activity, wound healing

  6. Non-Enzymatic Glucose Sensor Composed of Carbon-Coated Nano-Zinc Oxide

    Science.gov (United States)

    Chung, Ren-Jei; Wang, An-Ni; Liao, Qing-Liang; Chuang, Kai-Yu

    2017-01-01

    Nowadays glucose detection is of great importance in the fields of biological, environmental, and clinical analyzes. In this research, we report a zinc oxide (ZnO) nanorod powder surface-coated with carbon material for non-enzymatic glucose sensor applications through a hydrothermal process and chemical vapor deposition method. A series of tests, including crystallinity analysis, microstructure observation, and electrochemical property investigations were carried out. For the cyclic voltammetric (CV) glucose detection, the low detection limit of 1 mM with a linear range from 0.1 mM to 10 mM was attained. The sensitivity was 2.97 μA/cm2mM, which is the most optimized ever reported. With such good analytical performance from a simple process, it is believed that the nanocomposites composed of ZnO nanorod powder surface-coated with carbon material are promising for the development of cost-effective non-enzymatic electrochemical glucose biosensors with high sensitivity.

  7. Removal of Chromium(VI from aqueous solution using guar gum–nano zinc oxide biocomposite adsorbent

    Directory of Open Access Journals (Sweden)

    Tabrez A. Khan

    2017-05-01

    Full Text Available Guar gum–nano zinc oxide (GG/nZnO biocomposite was used as an adsorbent for enhanced removal of Cr(VI from aqueous solution. The maximum adsorption was achieved at 50 min contact time, 25 mg/L Cr(VI conc., 1.0 g/L adsorbent dose and 7.0 pH. Langmuir, Freundlich, Dubinin–Kaganer–Radushkevich and Temkin isotherm models were used to interpret the experimental data. The data obeyed both Langmuir and Freundlich models (R2 = 0.99 indicating a multilayer adsorption of Cr(VI onto the heterogeneous surface. The linear plots of Temkin isotherm showed adsorbent-adsorbate interactions. Moreover, the energy obtained from DKR isotherm (1.58–2.24 kJ/mol indicated a physical adsorption of the metal ions onto the adsorbent surface, which implies more feasibility of the regeneration of the adsorbent. GG/nZnO biocomposite adsorbent showed an improved adsorption capacity for Cr(VI (qm = 55.56 mg/g as compared to other adsorbents reported in the literature. Adsorption process followed pseudo-second order kinetics; controlled by both liquid-film and intra-particle diffusion mechanisms. Thermodynamic parameters (ΔGo, ΔHo and ΔSo reflected the feasibility, spontaneity and exothermic nature of adsorption. The results suggested that GG/nZnO biocomposite is economical, eco-friendly and capable to remove Cr(VI from natural water resources.

  8. Laser material purification of neodymium. Hikari reiki seiseiho ni yoru neodymium no kojundoka

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Y.; Ozaki, T.; Yoshimatsu, S. (National Research Institute for Metals, Tokyo (Japan)); Chiba, K.; Umeda, H.; Saeki, M. (Nippon Steel Corp., Tokyo (Japan))

    1991-05-20

    Selective photoexcitation and photoionization of neodymium atoms were studied basically by using laser. Also, using their properties, feasibility of laser material purification (LPM) technology in gaseous phase was presented. In the selective 3-step ionization, laser beam with two kinds of proper wave length causes resonance exitation of the target element, which goes up to the excitation level of the first step, and the element is ionized by the second laser beam and the third laser beam. The 3-step ionization scheme by a single wave length laser beam of 577.612nm was used for the ionization of Nd. Nd ionized selectively by laser beam was recovered as thin layer at the negative potential side of plane electrodes placed at both sides of the laser irradiation area. In the layer formed by the TPD technology with this scheme, it is possible to decrease impuritis such as Pr by 1/16 and to form highly purified thin layer. 13 refs., 12 figs., 1 tab.

  9. INFLUENCES OF NEODYMIUM ON MAGNETIC CHARACTERISTICS OF ELECTROPLATING CoNdNiMnP FILMS

    Institute of Scientific and Technical Information of China (English)

    H.C. Jiang; W.L. Zhang; J.P. Zhang; W.X. Zhang; B. Peng; S. Q. Yang

    2005-01-01

    In order to improve the performances of electroplating permanent magnetic films, neodymium is introduced into the electroplating CoNiMnP permanent magnetic films. The influences of the neodymium content are also investigated by varying NdCl3 plating bath concentration. The neodymium-doped films are analyzed by energy dispersive spectrum (EDS), vibrating sample magnetometer (VSM) and magnetic force microscope (MFM). The experimental results show that high magnetic performances of CoNdNiMnP permanent magnetic films with verticalanisotropy could be fabricated with current density 5mA/cm2 at room temperature. With the in creasing of neodymium contents, the magnetic properties of films were improved. However when neodymium contents exceeded 3.5wt%, the magnetic properties of films are not improved any more. The increase of film magnetic properties results from the ferromagnetic-coupling between light rare earth element-neodymium and transition metal element-cobalt.

  10. Efficiency increase in flexible bulk heterojunction solar cells with a nano-patterned indium zinc oxide anode

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dong Hwan; Seifter, Jason; Heeger, Alan J. [Center for Polymers and Organic Solids, University of California at Santa Barbara, Santa Barbara, California 93106-5090 (United States); Park, Jong Hyeok [School of Chemical Engineering and SAINT, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Choi, Dae-Geun [Nano-Mechanical Systems Research Division, Korea Institute of Machinery and Materials (KIMM), 171 Jang-dong, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of)

    2012-11-15

    Efficient flexible bulk-heterojunction polymer solar cells based on PCDTBT/PC{sub 70}BM were successfully fabricated by a simple nano-imprint technique. The flexible nano-patterned IZO anode with ordered periodic dot structures led to improved light absorption and increased interfacial contact area between the anode and polymer as well as between the polymer and cathode. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Thermal degradation of epoxidized natural rubber in presence of neodymium stearate

    Institute of Scientific and Technical Information of China (English)

    LUO Yongyue; YANG Changjin; CHEN Bangqian; XU Kui; ZHONG Jieping; PENG Zheng; L(U) Zhen

    2013-01-01

    The effect of neodymium stearate (NdSt) synthesized by saponification method on thermal degradation and thermo-oxida-tive degradation of expoxidized natural rubber with 25 mol.% epoxidation (ENR25) was investigated by thermogravimetric analysis (TGA),and the structure of ENR25 vulcanized with NdSt after thermo-oxidative decomposition was characterized using Fourier transform infared spectroscopy-attenuated total-reflectance (FTIR-ATR).The thermal degradation kinetic parameters of ENR25 with different loadings of NdSt were determined by Coats-Redfern method.The results showed that the thermal degradation of ENR25 in nitrogen was a one-step reaction regardless of NdSt content,whereas the thermo-oxidative degradation was a multiple-step reaction.The thermal and thermo-oxidative stability of the ENR25 vulcanizates with the addition of NdSt was higher than that of pure ENR25 vulcanizates.The ENR25 vulcanizates with the incorporation of 1 phr (per hundred parts of rubber) NdSt imparted the highest activation energy (E) of thermal and thermo-oxidative degradation.This could be attributed to the many unoccupied orbits in rare earth Nd,which could capture the free radicals and make the epoxide groups stable in the process of thermal and thermo-oxidative degradation for ENR25.

  12. The measurement of stress and phase fraction distributions in pre and post-transition Zircaloy oxides using nano-beam synchrotron X-ray diffraction

    Science.gov (United States)

    Swan, H.; Blackmur, M. S.; Hyde, J. M.; Laferrere, A.; Ortner, S. R.; Styman, P. D.; Staines, C.; Gass, M.; Hulme, H.; Cole-Baker, A.; Frankel, P.

    2016-10-01

    Zircaloy-4 oxide stress profiles and tetragonal:monoclinic oxide phase fraction distributions were studied using nano-beam transmission X-ray diffraction. Continuous stress relief and phase transformation during the first cycle of oxide growth was observed. The in-plane monoclinic stress was shown to relax strongly up to each transition, whereas in-plane tetragonal stress-relief (near the metal-oxide interface) was only observed post transition. The research demonstrates that plasticity in the metal and the development of a band of in-plane cracking both relax the monoclinic in-plane stress. The observations are consistent with a model of transition in which in-plane cracking becomes interlinked prior to transition. These cracks, combined with the development of cracks with a through-thickness component (driven primarily by plasticity in the metal) and/or a porous network of fine cracks (associated with phase transformation), form a percolation path through the oxide layer. The oxidising species can then percolate from the oxide surface to the metal/oxide interface, at which stage transition then ensues.

  13. Polymerization of isoprene catalyzed by neodymium heterocyclic Schiff base complex

    Institute of Scientific and Technical Information of China (English)

    Lei Zhang; Xu Feng Ni; Wei Lin Sun; Zhi Quan Shen

    2008-01-01

    Neodymium-based heterocyclic Schiff base complex was prepared and applied for the coordination polymerization of isoprene. This complex polymerized isoprene to afford products featuring high cis-1,4 stereospecificity (ca. 95%) and high molecular weight (ca. 105) in the presence of the triisobutyl aluminium (AliBu3) as cocatalyst. The microstructure of obtained polyisoprene was investigated by FTIR, 1H NMR. Two different kinds of active centers in the catalyst system were examined by GPC method.

  14. Effect of gamma radiation and nano-zinc oxide content on the properties of recycled polycarbonate; Efeito de radiacao gama e do teor de oxido de zinco nanometrico nas propriedades do policarbonato reciclado

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Ana Luiza F.; Mendes, Luis C.; Cestari, Sibele P., E-mail: lcmendes@ima.ufrj.br [Universidade Federal do Rio de Janeiro (IFRJ), Rio de Janeiro-RJ (Brazil). Instituto de Macromoleculas Eloisa Mano; Souza, Mauro C.L. [Universidade Estadual da Zona Oeste (UEZO), Campo Grande, RJ (Brazil)

    2013-07-01

    In order to promote the barrier action to the ultraviolet radiation and increase of mechanical characteristics, nanocomposites of recycled polycarbonate (rPC) and nano-zinc oxide (nZnO) containing 1, 2 and 3 % (wt/wt) of nano oxide were prepared. Since for obtaining nanocomposites and irradiating polymers are promising tools and attractive for improving the material performance, the effects of nano-zinc oxide and gamma radiation, at doses ranged from 10 to 50 kGy, were evaluated in terms of thermal characteristics of the rPC. The rPC/nZnO nanocomposites were characterized by thermogravimetric analysis (TGA), differential exploratory calorimetry (DSC), infrared spectrometry (FT-IR) and wide angle X-ray diffraction (WAXD). There was a progressive decrease of the T{sub g} as function of gamma dosage and nano-zinc oxide content. Initially, the T{sub onset} and T{sub max} decayed as function of gamma dosage but a recovery was observed. The amount of nano-zinc oxide induced a decreasing of T{sub onset} and T{sub max}. (author)

  15. Deposition of nano Fe3O4@mZrO2 onto exfoliated graphite oxide sheets and its application for removal of amaranth

    Science.gov (United States)

    Jiang, Hualin; Chen, Pinghua; Zhang, Weibo; Luo, Shenglian; Luo, Xubiao; Au, Chaktong (Peter); Li, Menglin

    2014-10-01

    Herein we report a novel method to exfoliate graphite to thin structure by depositing nanoparticles. Graphite was oxidated to graphite oxide (GO), and then nano Fe3O4@mZrO2 was loaded and inserted between GO sheets as GO being reduced to reduced graphite oxide (rGO) in one step by hydro-thermal co-precipitation. As-obtained nanocomposite Fe3O4@mZrO2/rGO was characterized by SEM, TEM, AFM, FT-IR, BET, XRD, VSM and EDX techniques. The microscopic studies show the thickness of Fe3O4@mZrO2/rGO sheet is significant thinner than that of rGO sheet. Evidences indicate the presence of nano Fe3O4@mZrO2 effectively preserves rGO sheets from stacking and forming thick structure. Amaranth was used as a model contamination to investigate the adsorption ability of the nanocomposite due to its hazardness. It shows effective adsorption ability. Based on all the evidence shown in studies, a possible mechanism for the adsorbent composing and its amaranth adsorption was postulated.

  16. Water exchange in manganese-based water-oxidizing catalysts in photosynthetic systems: from the water-oxidizing complex in photosystem II to nano-sized manganese oxides.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Isaloo, Mohsen Abbasi; Eaton-Rye, Julian J; Tomo, Tatsuya; Nishihara, Hiroshi; Satoh, Kimiyuki; Carpentier, Robert; Shen, Jian-Ren; Allakhverdiev, Suleyman I

    2014-09-01

    The water-oxidizing complex (WOC), also known as the oxygen-evolving complex (OEC), of photosystem II in oxygenic photosynthetic organisms efficiently catalyzes water oxidation. It is, therefore, responsible for the presence of oxygen in the Earth's atmosphere. The WOC is a manganese-calcium (Mn₄CaO₅(H₂O)₄) cluster housed in a protein complex. In this review, we focus on water exchange chemistry of metal hydrates and discuss the mechanisms and factors affecting this chemical process. Further, water exchange rates for both the biological cofactor and synthetic manganese water splitting are discussed. The importance of fully unveiling the water exchange mechanism to understand the chemistry of water oxidation is also emphasized here. This article is part of a special issue entitled: photosynthesis research for sustainability: keys to produce clean energy.

  17. 氨法制取纳米氧化锌的粒径控制研究%Particle size control of nano - sized zinc oxide by ammonia process

    Institute of Scientific and Technical Information of China (English)

    蔡建国; 蔡睿敏

    2009-01-01

    为有效控制氨法制取纳米氧化锌的粒径,在蒸氨前将浸出原液用一定量的纯净水稀释,可增加初期沉淀生成的晶核数,使沉淀粒径更加均匀和细化,同时发现蒸氨残液不可以作为浸出原液的稀释剂回用.蒸氨的加热方式对纳米氧化锌的粒径也有影响,选择蒸汽直接加热,当溶液含锌质量浓度小于0.3 g/L时,所制取的纳米氧化锌粒径满足GB/T 19589-2004纳米氧化锌的要求 .%In order to effectively control the particle size of nano - sized zinc oxide prepared by ammonia process,leaching stock solution was diluted with a certain amount of purified water before ammonia distillation process,which could increase the quantity of crystal nucleus generated by initial precipitation and make particle size of precipitate more uniform and refined.Meanwhile,it was found that distilled ammonia residual liquid could not be served as diluent of leaching stock solution for recycling.Also,heating method of ammonia distillation will affect the particle size of nano - sized zinc oxide.Particle size of prepared nano - sized zinc oxide can satisfy the requirements of GB/T 19589-2004,when direct steam heating was selected and mass concentration of zinc in the solution was less than 0.3 g/L.

  18. Oil/water nano-emulsion loaded with cobalt ferrite oxide nanocubes for photo-acoustic and magnetic resonance dual imaging in cancer: in vitro and preclinical studies.

    Science.gov (United States)

    Vecchione, Raffaele; Quagliariello, Vincenzo; Giustetto, Pierangela; Calabria, Dominic; Sathya, Ayyappan; Marotta, Roberto; Profeta, Martina; Nitti, Simone; Silvestri, Niccolò; Pellegrino, Teresa; Iaffaioli, Rosario V; Netti, Paolo Antonio

    2017-01-01

    Dual imaging dramatically improves detection and early diagnosis of cancer. In this work we present an oil in water (O/W) nano-emulsion stabilized with lecithin and loaded with cobalt ferrite oxide (Co0.5Fe2.5O4) nanocubes for photo-acoustic and magnetic resonance dual imaging. The nanocarrier is responsive in in vitro photo-acoustic and magnetic resonance imaging (MRI) tests. A clear and significant time-dependent accumulation in tumor tissue is shown in in vivo photo-acoustic studies on a murine melanoma xenograft model. The proposed O/W nano-emulsion exhibits also high values of r2/r1 (ranging from 45 to 85, depending on the magnetic field) suggesting a possible use as T2 weighted image contrast agents. In addition, viability and cellular uptake studies show no significant cytotoxicity on the fibroblast cell line. We also tested the O/W nano-emulsion loaded with curcumin against melanoma cancer cells demonstrating a significant cytotoxicity and thus showing possible therapeutic effects in addition to the in vivo imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. 纳米改性矿物绝缘油的老化特性研究%Oxidation Resistance Study of Nano-Particles Modiifed Mineral Transformer Oil

    Institute of Scientific and Technical Information of China (English)

    马军; 周月梅; 朱正国; 舒俊; 黄超

    2016-01-01

    The preparative nano-modiifcation mineral oil was taken as the specimen to respectively test oil sample micro-water content, break-down voltage, dielectric loss and acid value for the mineral transformer oil with the temperature of 100℃ and 35 days aging at the intervals of 7 days before and after nano-particles added, to examine the property of the mineral transformer oil before and after aging. The test results show that the physicochemical and electrical properties of different types of mineral transformer oil after aging have different degrees of degradation and deterioration, and the oxidation resistance of nano-particles mineral oil is better.%以制备的纳米改性矿物油为研究样品,对添加纳米颗粒前后矿物绝缘油在100℃、老化35天、每隔7天分别测试油样微水含量、击穿电压、介质损耗及酸值,考核老化前后矿物绝缘油性能。测试结果显示,老化前后不同矿物绝缘油理化电气性能均会出现不同程度劣化,添加有纳米颗粒的矿物油表现出更好的抗氧化性能。

  20. Comparison of acute oxidative stress on rat lung induced by nano and fine-scale, soluble and insoluble metal oxide particles: NiO and TiO2.

    Science.gov (United States)

    Horie, Masanori; Fukui, Hiroko; Endoh, Shigehisa; Maru, Junko; Miyauchi, Arisa; Shichiri, Mototada; Fujita, Katsuhide; Niki, Etsuo; Hagihara, Yoshihisa; Yoshida, Yasukazu; Morimoto, Yasuo; Iwahashi, Hitoshi

    2012-06-01

    The aim of the present study is to understand the association between metal ion release from nickel oxide (NiO) nanoparticles and induction of oxidative stress in the lung. NiO nanoparticles have cytotoxic activity through nickel ion release and subsequent oxidative stress. However, the interaction of oxidative stress and nickel ion release in vivo is still unclear. In the present study, we examined the effect of metal ion release on oxidative stress induced by NiO nanoparticles. Additionally, nano and fine TiO(2) particles as insoluble particles were also examined. Rat lung was exposed to NiO and TiO(2) nanoparticles by intratracheal instillation. The NiO nanoparticles released Ni(2+) in dispersion. Bronchoalveolar lavage fluid (BALF) was collected at 1, 24, 72 h and 1 week after instillation. The lactate dehydrogenase (LDH) and HO-1 levels were elevated at 24 and 72 h after instillation in the animals exposed to the NiO nanoparticles. On the other hand, total hydroxyoctadecadienoic acid (tHODE), which is an oxidative product of linoleic acid, as well as SP-D and α-tochopherol levels were increased at 72 h and 1 week after instillation. Fine NiO particles, and nano and fine TiO(2) particles did not show lung injury or oxidative stress from 1 h to 1 week after instillation. These results suggest that Ni(2+) release is involved in the induction of oxidative stress by NiO nanoparticles in the lung. Ni(2+) release from NiO nanoparticles is an important factor inoxidative stress-related toxicity, not only in vitro but also in vivo.

  1. Comparative studies of neodymium (III)-selective PVC membrane sensors

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Vinod K., E-mail: vinodfcy@iitr.ernet.in [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India); Goyal, Rajendra N.; Sharma, Ram A. [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India)

    2009-08-04

    Sensors based on two neutral ionophores, N,N'-bis((1H-pyrrol-2-yl)methylene)cyclohexane-1,2-diamine (L{sub 1}) and 3,3'-(cyclohexane-1,2-diylbis(azan-1-yl-1-ylidene) bis(methan-1-yl-1-ylidene)bis(5-hydroxymethyl)pyridine-2-ol) (L{sub 2}) are described for quantification of neodymium (III). Effect of various plasticizers; 2-nitrophenyloctylether (o-NPOE), dibutyl butylphosphonate (DBBP), tri-n-butyl phosphates (TBP), dioctylpthalate (DOP) and chloronapthalen (CN) and anion excluder, sodiumtetraphenylborate (NaTPB) has been studied. The membrane composition of PVC:o-NPOE:ionophore (L{sub 1}):NaTPB (w/w; mg) of 150:300:5:5 exhibited best performance. The sensor with ionophore (L{sub 1}) exhibits significantly enhanced selectivity towards neodymium (III) in the concentration range 5.0 x 10{sup -7} to 1.0 x 10{sup -2} M with a detection limit of 1.0 x 10{sup -7} M and a Nernstian compliance (19.8 {+-} 0.3 mV decade{sup -1} of activity) within pH range 4.0-8.0. The response time of sensor was found as 10 s. The influence of the membrane composition and possible interfering ions has also been investigated on the response properties of the electrode. The fast and stable response, good reproducibility and long-term stability of the sensor are observed. The sensor has been found to work satisfactorily in partially non-aqueous media up to 20% (v/v) content of methanol, ethanol or acetonitrile and could be used for a period of 3 months. The selectivity coefficients determined by using fixed interference method (FIM) indicate high selectivity for neodymium. The proposed electrode shows fairly good discrimination of neodymium (III) from other cations. The application of prepared sensor has been demonstrated in the determination of neodymium (III) in spiked water samples.

  2. Graphene oxide selectively targets cancer stem cells, across multiple tumor types: implications for non-toxic cancer treatment, via "differentiation-based nano-therapy".

    Science.gov (United States)

    Fiorillo, Marco; Verre, Andrea F; Iliut, Maria; Peiris-Pagés, Maria; Ozsvari, Bela; Gandara, Ricardo; Cappello, Anna Rita; Sotgia, Federica; Vijayaraghavan, Aravind; Lisanti, Michael P

    2015-02-28

    Tumor-initiating cells (TICs), a.k.a. cancer stem cells (CSCs), are difficult to eradicate with conventional approaches to cancer treatment, such as chemo-therapy and radiation. As a consequence, the survival of residual CSCs is thought to drive the onset of tumor recurrence, distant metastasis, and drug-resistance, which is a significant clinical problem for the effective treatment of cancer. Thus, novel approaches to cancer therapy are needed urgently, to address this clinical need. Towards this end, here we have investigated the therapeutic potential of graphene oxide to target cancer stem cells. Graphene and its derivatives are well-known, relatively inert and potentially non-toxic nano-materials that form stable dispersions in a variety of solvents. Here, we show that graphene oxide (of both big and small flake sizes) can be used to selectively inhibit the proliferative expansion of cancer stem cells, across multiple tumor types. For this purpose, we employed the tumor-sphere assay, which functionally measures the clonal expansion of single cancer stem cells under anchorage-independent conditions. More specifically, we show that graphene oxide effectively inhibits tumor-sphere formation in multiple cell lines, across 6 different cancer types, including breast, ovarian, prostate, lung and pancreatic cancers, as well as glioblastoma (brain). In striking contrast, graphene oxide is non-toxic for "bulk" cancer cells (non-stem) and normal fibroblasts. Mechanistically, we present evidence that GO exerts its striking effects on CSCs by inhibiting several key signal transduction pathways (WNT, Notch and STAT-signaling) and thereby inducing CSC differentiation. Thus, graphene oxide may be an effective non-toxic therapeutic strategy for the eradication of cancer stem cells, via differentiation-based nano-therapy.

  3. Enhancement of the photocatalytic activity of Ferrous Oxide by doping onto the nano-clinoptilolite particles towards photodegradation of tetracycline.

    Science.gov (United States)

    Nezamzadeh-Ejhieh, Alireza; Shirzadi, Arezoo

    2014-07-01

    Photodegradation of tetracycline (TC) aqueous solution by FeO doped onto nano-clinoptilolite particles was investigated using a high pressure Hg lamp as radiation source. Nano-particles of clinoptilolite were prepared using ball-milling of micro crystals of zeolite. The pretreated nano-particles ion exchanged in a ferrous solution and the Fe(II)-exchanged form was calcined at 450°C. All samples were characterized by FT-IR, DRS, SEM and XRD. The degradation extent was determined via UV-Vis absorption spectroscopy and COD. Based on the study of the effect of key operating parameters, the optimal conditions were determined to reach the higher efficiency of the process. The best photocatalytic activity was obtained in presence of the catalyst containing 5.4% FeO.

  4. Effect of Au Precursor and Support on the Catalytic Activity of the Nano-Au-Catalysts for Propane Complete Oxidation

    National Research Council Canada - National Science Library

    Ali, Arshid M; Daous, Muhammad A; Arafat, Ahmed; AlZahrani, Abdulraheem A; Alhamed, Yahia; Tuerdimaimaiti, Abudula; Petrov, Lachezar A

    2015-01-01

    ...(s) for the propane oxidation. Oxidation state, size, and dispersion of Au nanoparticles in the Au-catalysts, surface area, crystallinity, phase structure, and redox property of the support are the key aspects for the complete propane oxidation...

  5. Dry reforming of methane on Ni-Mg-Al nano-spheroid oxide catalysts prepared by the sol-gel method from hydrotalcite-like precursors

    Science.gov (United States)

    González, Albert R.; Asencios, Yvan J. O.; Assaf, Elisabete M.; Assaf, José M.

    2013-09-01

    Nanocapsular hydrotalcites (layered double hydroxides - LDHs) were synthesized by the sol-gel method and used as precursors of nano-structured mixed oxides containing various nickel loads (4, 15 and 19 wt%). The best conditions for the preparation of LDHs were analyzed and the structures of the resulting mixed oxides were studied. The optimal nickel load and calcining conditions were optimized. Finally, the resulting catalysts were tested in the dry reforming of methane for 8 h at 800 °C under atmospheric pressure. These materials showed high activity and stability, and the coke deposits were minimal on the catalyst prepared under optimal conditions (19 wt% nickel load and thermal treatment at 650 °C). The best catalyst formed amorphous carbon, which seems not to be prejudicial to the reaction.

  6. Application and security of nano zinc oxide in food field%纳米氧化锌在食品领域中的应用及安全性研究进展

    Institute of Scientific and Technical Information of China (English)

    何星平; 杨鹏飞; 况慧娟; 许恒毅

    2016-01-01

    ABSTRACT:Nano zinc oxide (ZnO) has become the research hotspots in the field of antibacterial materials due to its extraordinary antibacterial ability. However, with the widely application in the field of food packaging and food additives, nano zinc oxide may enter the organism inevitably, which can cause harm to human health. Therefore, the biological safety of nano zinc oxide has aroused widespread concern. This paper summarized the latest research findings about nano zinc oxide, described the application of nano zinc oxide in the field of food, and introduced the potential effects of genetic, immune, reproductive and nervous toxicity caused by nano zinc oxide. In addition, the influence factors associated with the toxicity of nano zinc oxide were discussed in detail, which could provide references for future research and application of nano zinc oxide in the field of food.%纳米氧化锌因其具有良好的抗菌性能已成为目前抗菌材料的研究热点。然而,随着纳米氧化锌在食品包装材料和食品添加剂等领域的广泛应用,其将不可避免地进入到生物体内,从而对人体健康造成一定危害,因此其生物安全性也引起了广泛关注。本文通过总结和归纳相关的研究报道,阐述了纳米氧化锌在食品领域的应用,并介绍了其可能引起的遗传、免疫、生殖、神经等毒性效应,深入探讨了纳米氧化锌相关毒性的影响因素,以期为今后纳米氧化锌在食品领域的研究和应用提供参考。

  7. Do foraminifera accurately record seawater neodymium isotope composition?

    Science.gov (United States)

    Scrivner, Adam; Skinner, Luke; Vance, Derek

    2010-05-01

    Palaeoclimate studies involving the reconstruction of past Atlantic meridional overturning circulation increasingly employ isotopes of neodymium (Nd), measured on a variety of sample media (Frank, 2002). In the open ocean, Nd isotopes are a conservative tracer of water mass mixing and are unaffected by biological and low-temperature fractionation processes (Piepgras and Wasserburg, 1987; Lacan and Jeandel, 2005). For decades, benthic foraminifera have been widely utilised in stable isotope and geochemical studies, but have only recently begun to be exploited as a widely distributed, high-resolution Nd isotope archive (Klevenz et al., 2008), potentially circumventing the difficulties associated with other methods used to recover past deep-water Nd isotopes (Klevenz et al., 2008; Rutberg et al., 2000; Tachikawa et al., 2004). Thus far, a single pilot study (Klevenz et al., 2008) has indicated that core-top sedimentary benthic foraminifera record a Nd isotope composition in agreement with the nearest available bottom seawater data, and has suggested that this archive is potentially useful on both millennial and million-year timescales. Here we present seawater and proximal core-top foraminifer Nd isotope data for samples recovered during the 2008 "RETRO" cruise of the Marion Dufresne. The foraminifer samples comprise a depth-transect spanning 3000m of the water column in the Angola Basin and permit a direct comparison between high-resolution water column and core-top foraminiferal Nd isotope data. We use these data to assess the reliability of both planktonic and benthic foraminifera as recorders of water column neodymium isotope composition. Frank, M., 2002. Radiogenic isotopes: Tracers of past ocean circulation and erosional input, Rev. Geophys., 40 (1), 1001, doi:10.1029/2000RG000094. Klevenz, V., Vance, D., Schmidt, D.N., and Mezger, K., 2008. Neodymium isotopes in benthic foraminifera: Core-top systematics and a down-core record from the Neogene south Atlantic

  8. Effect of transscleral neodymium: YAG cyclophotocoagulation on intraocular lenses

    Energy Technology Data Exchange (ETDEWEB)

    Blomquist, P.H.; Gross, R.L.; Koch, D.D. (Baylor College of Medicine, Houston, TX (USA))

    1990-03-01

    A neodymium: YAG laser operating in the thermal mode was used to irradiate isolated intraocular lenses (IOLs) and to perform transscleral cyclophotocoagulation on pseudophakic autopsy eyes to investigate the potential damage to IOL haptics such irradiation may cause. In the isolated IOLs, 70 mJ of energy deformed and partially melted both polymethylmethacrylate (PMMA) and polypropylene haptics. One of the capsular-fixated PC-IOL haptics in an autopsy eye partially melted when irradiated with the maximum energy level (8.8 J), with the aiming beam focused 1 mm posterior to the limbus and maximal posterior focus offset.

  9. Comparative study of genotoxicity and tissue distribution of nano and micron sized iron oxide in rats after acute oral treatment

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Shailendra Pratap; Rahman, M.F.; Murty, U.S.N.; Mahboob, M.; Grover, Paramjit, E-mail: paramgrover@gmail.com

    2013-01-01

    Though nanomaterials (NMs) are being utilized worldwide, increasing use of NMs have raised concerns over their safety to human health and environment. Iron oxide (Fe{sub 2}O{sub 3}) NMs have important applications. The aim of this study was to assess the genotoxicity of Fe{sub 2}O{sub 3}-30 nm and Fe{sub 2}O{sub 3}-bulk in female Wistar rats. Fe{sub 2}O{sub 3}-30 nm was characterized by using transmission electron microscopy, dynamic light scattering, laser Doppler velocimetry and surface area analysis. The rats were treated orally with the single doses of 500, 1000, 2000 mg/kg bw of Fe{sub 2}O{sub 3}-30 nm and Fe{sub 2}O{sub 3} –bulk. The genotoxicity was evaluated at 6, 24, 48 and 72 h by the comet assay in leucocytes, 48 and 72 h by micronucleus test (MNT) in peripheral blood cells, 18 and 24 h by chromosomal aberration (CA) assay and 24 and 48 h by MNT in bone marrow cells. The biodistribution of iron (Fe) was carried out at 6, 24, 48 and 72 h after treatment in liver, spleen, kidney, heart, brain, bone marrow, urine and feces by using atomic absorption spectrophotometry. The % tail DNA, frequencies of micronuclei and CAs were statistically insignificant (p > 0.05) at all doses. These results suggest that Fe{sub 2}O{sub 3}-30 nm and Fe{sub 2}O{sub 3}-bulk was not genotoxic at the doses tested. Bioavailability of Fe was size and dose dependent in all the tissues from the groups exposed to Fe{sub 2}O{sub 3}-30 nm. Fe{sub 2}O{sub 3} NMs were able to enter in the organs and the rats are biocompatible with much higher concentration of Fe. However, the accumulated Fe did not cause significant genotoxicity. This study provides additional knowledge about the toxicology of Fe{sub 2}O{sub 3} NMs. -- Highlights: ► Fe{sub 2}O{sub 3}-30 nm and Fe{sub 2}O{sub 3}-bulk were orally administered to rats with single doses. ► The nano and bulk Fe{sub 2}O{sub 3} showed insignificant results with MNT, comet and CA assays. ► The bulk was excreted via feces whereas the NMs

  10. Solar absorptance of copper–cobalt oxide thin film coatings with nano-size, grain-like morphology: Optimization and synchrotron radiation XPS studies

    Energy Technology Data Exchange (ETDEWEB)

    Amri, Amun [School of Engineering and Energy, Murdoch University, Murdoch, 6150 WA (Australia); Department of Chemical Engineering, Riau University, Pekanbaru (Indonesia); Duan, XiaoFei [School of Chemistry, The University of Melbourne, VIC 3010 (Australia); Yin, Chun-Yang, E-mail: c.yin@murdoch.edu.au [School of Chemical and Mathematical Sciences, Murdoch University, Murdoch, 6150 WA (Australia); Jiang, Zhong-Tao, E-mail: z.jiang@murdoch.edu.au [School of Engineering and Energy, Murdoch University, Murdoch, 6150 WA (Australia); Rahman, M. Mahbubur; Pryor, Trevor [School of Engineering and Energy, Murdoch University, Murdoch, 6150 WA (Australia)

    2013-06-15

    Copper–cobalt oxides thin films had been successfully coated on reflective aluminium substrates via a facile sol–gel dip-coating method for solar absorptance study. The optimum absorptance in the range of solar radiation is needed for further optimum design of this material for selective solar absorber application. Field emission scanning electron microscopy was used to characterize the surface morphology of the coating whereby nano-size, grain-like morphology was observed. Synchrotron radiation X-ray photoelectron spectroscopy was employed to analyze the electronic structure of the coated surface showing that the (i) oxygen consisted of lattice, surface and subsurface oxygen, (ii) copper consisted of octahedral and tetrahedral Cu{sup +}, as well as octahedral and paramagnetic Cu{sup 2+} oxidation states, and (iii) cobalt consisted of tetrahedral and paramagnetic Co(II), octahedral Co(III) as well as mixed Co(II,III) oxidation states. In order to optimize the solar absorptance of the coatings, relevant parameters such as concentrations of cobalt and copper, copper/cobalt concentration ratios and dip-speed were investigated. The optimal coating with α = 83.4% was produced using 0.25 M copper acetate and 0.25 M cobalt chloride (Cu/Co ratio = 1) with dip-speed 120 mm/min (four cycles). The operational simplicity of the dip-coating system indicated that it could be extended for coating of other mixed metal oxides as well.

  11. Epitaxial Fe Thin Films on {100} Y2Ti2O7: Model Interfaces for Nano-Oxide Dispersion Strengthened Steels

    Science.gov (United States)

    Stan, T.; Wu, Y.; Wells, P. B.; Zhou, H. D.; Odette, G. R.

    2017-08-01

    Nanostructured Ferritic Alloys, a variant of oxide dispersion strengthened steels, contain a high density of ≈2.5 nm Y-Ti-O nano-oxides (NOs) that provide remarkable irradiation tolerance, enhance recombination of vacancies and self-interstitial irradiation defects, and trap He in fine-scale bubbles at their interfaces. To complement studies of embedded NOs, mesoscopic-scale metal-oxide interfaces were fabricated by electron beam deposition of Fe films on {100} Y2Ti2O7 (YTO) bulk single-crystal substrates. We report, for the first time, the dominant epitaxial orientation relationship (OR) for the polycrystalline Fe film: {110}Fe{100}YTO and 〈111〉Fe〈110〉YTO. Further, one large grain region had an OR that is also found in embedded NOs: {100}Fe{100}YTO and 〈100〉Fe〈110〉YTO. HRTEM studies show clean, semicoherent interfaces with misfit dislocation spacings of 0.7 and 1.4 nm, respectively. These observations are important for the development of first principles models of metal-oxide interfaces, and the bilayers themselves will be used to observe the He partitioning between the Fe, YTO, and the corresponding interface.

  12. Magnetic solid phase extraction of gemfibrozil from human serum and pharmaceutical wastewater samples utilizing a β-cyclodextrin grafted graphene oxide-magnetite nano-hybrid.

    Science.gov (United States)

    Abdolmohammad-Zadeh, Hossein; Talleb, Zeynab

    2015-03-01

    A magnetic solid phase extraction method based on β-cyclodextrin (β-CD) grafted graphene oxide (GO)/magnetite (Fe3O4) nano-hybrid as an innovative adsorbent was developed for the separation and pre-concentration of gemfibrozil prior to its determination by spectrofluorometry. The as-prepared β-CD/GO/Fe3O4 nano-hybrid possesses the magnetism property of Fe3O4 nano-particles that makes it easily manipulated by an external magnetic field. On the other hand, the surface modification of GO by β-CD leads to selective separation of the target analyte from sample matrices. The structure and morphology of the synthesized adsorbent were characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The experimental factors affecting the extraction/pre-concentration and determination of the analyte were investigated and optimized. Under the optimized experimental conditions, the calibration graph was linear in the range between 10 and 5000 pg mL(-1) with a correlation coefficient of 0.9989. The limit of detection and enrichment factor for gemfibrozil were 3 pg mL(-1) and 100, respectively. The maximum sorption capacity of the adsorbent for gemfibrozil was 49.8 mg g(-1). The method was successfully applied to monitoring gemfibrozil in human serum and pharmaceutical wastewaters samples with recoveries in the range of 96.0-104.0% for the spiked samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. A Method to Site-Specifically Identify and Quantitate Carbonyl End Products of Protein Oxidation Using Oxidation-Dependent Element Coded Affinity Tags (O-ECAT) and NanoLiquid Chromatography Fourier Transform Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S; Young, N L; Whetstone, P A; Cheal, S M; Benner, W H; Lebrilla, C B; Meares, C F

    2005-08-25

    Protein oxidation is linked to cellular stress, aging, and disease. Protein oxidations that result in reactive species are of particular interest, since these reactive oxidation products may react with other proteins or biomolecules in an unmediated and irreversible fashion, providing a potential marker for a variety of disease mechanisms. We have developed a novel system to identify and quantitate, relative to other states, the sites of oxidation on a given protein. A specially designed Oxidation-dependent carbonyl-specific Element-Coded Affinity Mass Tag (O-ECAT), AOD, ((S)-2-(4-(2-aminooxy)-acetamido)-benzyl)-1, 4, 7, 10-tetraazacyclododecane-N, N', N'', N'''-tetraacetic acid, is used to covalently tag the residues of a protein oxidized to aldehyde or keto end products. After proteolysis, the resulting AOD-tagged peptides are affinity purified, and analyzed by nanoLC-FTICR-MS, which provides high specificity in extracting co-eluting AOD mass pairs with a unique mass difference and affords relative quantitation based on isotopic ratios. Using this methodology, we have mapped the surface oxidation sites on a model protein, recombinant human serum albumin (rHSA) in its native form (as purchased) and after FeEDTA oxidation. A variety of modified amino acid residues including lysine, arginine, proline, histidine, threonine, aspartic and glutamic acids, were found to be oxidized to aldehyde and keto end products. The sensitivity of this methodology is shown by the number of peptides identified, twenty peptides on the native protein and twenty-nine after surface oxidation using FeEDTA and ascorbate. All identified peptides map to the surface of the HSA crystal structure validating this method for identifying oxidized amino acids on protein surfaces. In relative quantitation experiments between FeEDTA oxidation and native protein oxidation, identified sites showed different relative propensities towards oxidation independent of amino acid

  14. Nano-sized magnetic iron oxides as catalysts for heterogeneous Fenton-like reactions-Influence of Fe(II)/Fe(III) ratio on catalytic performance.

    Science.gov (United States)

    Rusevova, Klara; Kopinke, Frank-Dieter; Georgi, Anett

    2012-11-30

    Nano-sized Fe(II, III) oxides with various Fe(II)/Fe(III) ratios were characterized and tested as catalysts for the oxidative degradation of phenol via Fenton-like reactions at neutral pH. Under conditions typically applied for wet peroxide oxidation, Fe(II) in magnetite is oxidized to Fe(III), successively converting the mineral into maghemite. The residual Fe(II) content in the catalyst core is of only minor benefit for the catalytic activity in phenol oxidation, i.e. magnetite is not superior to maghemite. Achievable reaction rates for phenol degradation appeared to be rather low, e.g. phenol half-life of about 12 h when 3 g L(-1) magnetite and 5 g L(-1) H(2)O(2) were applied. Preceding surface-reduction of maghemite by NaBH(4), leading to an over-stoichiometric Fe(II) content compared to magnetite, only enhanced the non-productive decomposition of H(2)O(2) rather than the rate of phenol degradation. Reaction rates were shown to be relatively insensitive to catalyst concentration in the range of 1-10 g L(-1), probably resulting from a scavenging of reactive species by the catalyst surface, whereby particle agglomeration seems to play a key role. Degradation experiments with various structurally distinct compounds were carried out, indicating a similar selectivity of the heterogeneous Fenton-like system to that known for oxidation with ·OH. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. A comparative study of neodymium sorption by yeast cells

    Energy Technology Data Exchange (ETDEWEB)

    Vlachou, A.; Symeopoulos, B.D. [Univ. of Patras, Dept. of Chemistry (Greece); Koutinas, A.A. [Univ. of Patras, Dept. of Chemistry, Food Biotechnology Group (Greece)

    2009-07-01

    An approximate comparison of neodymium sorption at pH = 1.5, between the well studied Saccharomyces cerevisiae and three other related microorganisms (Kluyveromyces marxianus, Candida colliculosa and Debaromyces hansenii) was made. Although big differences were not observed, a slightly higher neodymium uptake was attained by the latter three kinds of yeasts. Their adsorption isotherms, varying the initial metal concentration from 10 to 200 mg/L, at constant ionic strength (I = 0.1 mol/L), could be fitted equally well, either to Langmuir or Freundlich adsorption model. Their estimated values of q{sub max} and K{sub f}, which are related to adsorption capacity, ranged from 10-12 mg/g and 0.90-1.2 respectively. The corresponding Scatchard plots suggest two types of bonding sites for all yeast studied and common receptor sites between C. colliculosa and D. hansenii. It is also discussed, the feasibility of using all these microorganisms, as potential detoxification tools, wherever contamination of foodstuffs by radionuclides, seems to be probable. (orig.)

  16. Extreme 54Cr-rich nano-oxides in the CI chondrite Orgueil -Implication for a late supernova injection into the Solar System

    CERN Document Server

    Qin, Liping; Alexander, Conel M O'D; Wang, Jianhua; Stadermann, Frank J; Carlson, Richard W; 10.1016/j.gca.2010.10.017

    2011-01-01

    Systematic variations in 54Cr/52Cr ratios between meteorite classes (Qin et al., 2010a; Trinquier et al., 2007) point to large scale spatial and/or temporal isotopic heterogeneity in the solar protoplanetary disk. Two explanations for these variations have been proposed, with important implications for the formation of the Solar System: heterogeneous seeding of the disk with dust from a supernova, or energetic-particle irradiation of dust in the disk. The key to differentiating between them is identification of the carrier(s) of the 54Cr anomalies. Here we report the results of our recent NanoSIMS imaging search for the 54Cr-rich carrier in the acid-resistant residue of the CI chondrite Orgueil. A total of 10 regions with extreme 54Cr-excesses ({\\delta}54Cr values up to 1500 %) were found. Comparison between SEM, Auger and NanoSIMS analyses showed that these 54Cr-rich regions are associated with one or more sub-micron (typically less than 200 nm) Cr oxide grains, most likely spinels. Because the size of the N...

  17. Effect of Y2O3 stabilized ZrO2 coating with tri-model structure on bi-layered thermally grown oxide evolution in nano thermal barrier coating systems at elevated temperatures

    Institute of Scientific and Technical Information of China (English)

    Mohammadreza Daroonparvar; Muhamad Azizi Mat Yajid; Noordin Mohd Yusof; Hamid Reza Bakhsheshi-Rad; Z Valefi; Esah Hamzah

    2014-01-01

    Bi-layered thermally grown oxide (TGO) layer plays a major role in the spallation of Y2O3 stabilized ZrO2 (YSZ) layer form the bond coat in the thermal barrier coating (TBC) systems during oxidation. On the other hand, bi-layered TGO formation and growth in the TBC systems with nanostructured YSZ have not been deeply investigated during cyclic oxidation. Hence, Inconel 738/NiCrAlY/normal YSZ and Inconel 738/NiCrAlY/nano YSZ systems were pre-oxidized at 1000 °C and then subjected to cyclic oxidation at 1150 °C. According to microstructural observations, nanostructured YSZ layer over the bond coat should have less mi-cro-cracks and pinholes, due to the compactness of the nanostructure and the presence of nano zones that resulted in lower O infiltration into the nanothermal barrier coating system, formation of thinner and nearly continuous mono-layered thermally grown oxide on the bond coat during pre-oxidation, lower spinels formation at the Al2O3/YSZ interface and finally, reduction of bi-layered thermally grown oxide thickness during cyclic oxidation. It was found that pre-heat treatment and particularly coating microstructure could influence microstructural evolution (bi-layered TGO thickness) and durability of thermal barrier coating systems during cyclic oxidation.

  18. Structural aspects and porosity features of nano-size high surface area alumina-silica mixed oxide catalyst generated through hybrid sol-gel route

    Energy Technology Data Exchange (ETDEWEB)

    Padmaja, P. [Ceramic Technology Division, Regional Research Laboratory (CSIR), Trivandrum 695019, Kerala (India)]. E-mail: padmavasudev@yahoo.com; Warrier, K.G.K. [Ceramic Technology Division, Regional Research Laboratory (CSIR), Trivandrum 695019, Kerala (India)]. E-mail: kgk_warrier@yahoo.com; Padmanabhan, M. [School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686560, Kerala (India); Wunderlich, W. [Graduate School of Engineering, Nagoya Institute of Technology, 466-8555 Nagoya (Japan); Berry, F.J. [Department of Chemistry, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Mortimer, M. [Department of Chemistry, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Creamer, N.J. [Department of Chemistry, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2006-01-10

    Alumina-silica mixed oxide nano-catalyst materials with compositions 83.6 wt.% Al{sub 2}O{sub 3}-16.4 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.1SiO{sub 2}), 71.82 wt.% Al{sub 2}O{sub 3}-28.18 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.2SiO{sub 2}), 62.84 wt.% Al{sub 2}O{sub 3}-37.16 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.3SiO{sub 2}) and 56.03 wt.% Al{sub 2}O{sub 3}-43.97 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.4SiO{sub 2}) have been prepared by a hybrid sol-gel technique using boehmite as the precursor for alumina and tetraethoxysilane as that for silica. The bonding characteristics and coordination features around Al and Si in the mixed oxide catalysts have been studied using FTIR and {sup 27}Al MAS NMR after calcination at 400 deg. C which is the temperature region where cross-condensation is seen to take place. A high BET specific surface area of 287 m{sup 2} g{sup -1} is obtained for 3Al{sub 2}O{sub 3}.1SiO{sub 2} mixed oxide composition. The porosity features are further established by BET adsorption isotherms and pore size distribution analysis. The temperature-programmed desorption studies showed more surface active sites for the silica-rich composition, suggesting enhanced catalytic potential. The TEM features of the mixed oxides showed a homogeneous distribution of alumina and silica phases with particle sizes in the nano-range. The low silica-containing mixed oxide showed a needle-like morphology with a high aspect ratio of 1:50 and {approx}10 nm particle size while the silica-rich composition had particle size in a wide range ({approx}20-75 nm)

  19. Catalytic Decomposition of Nitric Oxide over Nano-sized PbTiO3 Supported Cupric Oxide%纳米晶PbTiO3负载CuO催化NO分解

    Institute of Scientific and Technical Information of China (English)

    邢丽; 薛念华; 陈向科; 郭学锋; 丁维平; 陈懿

    2005-01-01

    A large specific surface area perovskite-type mixed oxide PbTiO3 supported cupric oxide was synthesized as a catalyst for NO decomposition and characterized by techniques such as XPS, XRD,H2-TPR before and after NO deconlposition reactions. The catalytic properties were tested with a fix-bed micro-reactor. The results showed that the PbTiO3 was inactive for the reactions, but 1wt % Cu/PbTiO3 catalyst gave fairly good activities for NO decomposition at temperature as low as 473K. Copper species were found well-dispersed but weakly interacted with the support before NO decomposition, and the NO decomposition caused significant change in the environment of the copper species, which became Cu(Ⅰ) and most probably incorporated into surface crystal lattice of the nano-sized PbTiO3. In NO reaction, a large amount of oxygen atoms from the decomposition of NO penetrated into the nano-sized PbTiO3 support and caused small expansion of crystal lattice. The transport of oxygen between the copper species and the catalyst support may be helpful to speed up the kinetic regeneration of active metal sites from oxygen occupancy and resulted in good catalytic performance.

  20. On adsorption of aluminium and methyl groups on silica for TMA/H2O process in atomic layer deposition of aluminium oxide nano layers

    Indian Academy of Sciences (India)

    Anu Philip; K Rajeev Kumar

    2010-04-01

    A detailed chemisorption mechanism is proposed for the atomic layer deposition (ALD) of aluminium oxide nano layers using trimethyl aluminum (TMA) and water as precursors. Six possible chemisorption mechanisms, complete ligand exchange, partial ligand exchange, simple dissociation, complete dissociation via ligand exchange, complete dissociation and association, are proposed and related parameters like ligand to metal ratio (L/M), concentrations of metal atoms and methyl groups adsorbed are calculated and compared against reported values. The maximum number of methyl groups that can get attached on the surface is calculated in a different way which yields a more realistic value of 6.25 per nm2 substrate area. The dependence of the number of metal atoms adsorbed on OH concentration is explained clearly. It is proposed that a combination of complete ligand exchange and complete dissociation is the most probable chemisorption mechanism taking place at various OH concentrations.

  1. 路面材料负载纳米二氧化钛光催化降解氮氧化物%PHOTOCATALYTIC OXIDATION OF NITROGEN OXIDES BY NANO-TiO2 IMMOBILIZED ON ROAD SURFACE MATERIALS

    Institute of Scientific and Technical Information of China (English)

    钱春香; 赵联芳; 付大放; 李丽; 王瑞兴

    2005-01-01

    随着汽车工业的发展,汽车尾气排放的氮氧化物对环境造成了巨大污染.以路面材料为载体,研究了负载型纳米二氧化钛对氮氧化物的降解作用.研究表明:水泥混凝土负载的光催化剂具有优越的光催化功能,而沥青混合料的较差.从载体对气体的吸附能力、吸光性和透光性等方面进-步研究了这两类载体的差异,提出了负载型纳米二氧化钛光催化降解氮氧化物的机理模型.%With the development of automobile industry, the tail gas of motor vehicles is one of major air pollution sources.Effects of nano-TiO2 photocatalytic oxidation immobilized on road surface materials on nitrogen oxides were investigated. Results show that the photocatalyst immobilized on concrete exhibits excellent photocatalysis, while the photocatalysis of bituminous mixture is poor. Differences between concrete and bituminous admixture as carriers in the adsorb-ability of molecule to air on surface, the light absorption and the light transmissibility are discussed. Moreover the mechanism model for photocatalytic oxidation of nitrogen oxides by supportive nano-TiO2 photocatalyst is put forward.

  2. Preparation and characteristics of nano-crystalline Cu-Ce-Zr-O composite oxides via a green route: supercritical anti-solvent process

    Institute of Scientific and Technical Information of China (English)

    KUANG Li; HUANG Pan; SUN Huanhua; JIANG Haoxi; ZHANG Minhua

    2013-01-01

    The nano-crystalline Cu-Ce-Zr-O composite oxides were successfully prepared by the supercritical anti-solvent (SAS) process.The physicochemical properties and catalytic performances were investigated by X-ray diffraction (XRD),Raman spectroscopy,H2 temperature-programmed reduction (H2-TPR),oxygen storage capacity (OSC) measurement and catalytic activity evaluation.It was found that Cu2+ ions incorporated into CeO2-ZrO2 lattice to forn Cu-Ce-Zr-O solid solution associated with the formation of oxygen vacancies.The Cu-Ce-Zr-O catalysts prepared via the SAS process with the Cu content 2.63 mol.% showed the highest OSC index of 636.9 μmol/g.Compared with the samples prepared by impregnation method,Cu doping using SAS process could improve the dispersion of Cu2+ in the composite oxide,enhance the interaction between Cu2+ and CeO2-ZrO2,improve the reducibility of catalyst,and thus improve the OSC performance and increase the catalytic activity for CO oxidation at low temperature.

  3. An oral absorbent, surface-deacetylated chitin nano-fiber ameliorates renal injury and oxidative stress in 5/6 nephrectomized rats.

    Science.gov (United States)

    Anraku, Makoto; Tabuchi, Ryo; Ifuku, Shinsuke; Nagae, Tomone; Iohara, Daisuke; Tomida, Hisao; Uekama, Kaneto; Maruyama, Toru; Miyamura, Shigeyuki; Hirayama, Fumitoshi; Otagiri, Masaki

    2017-04-01

    In this study, we report that surface-deacetylated chitin nano-fibers (SDACNFs) are more effective in decreasing renal injury and oxidative stress than deacetylated chitin powder (DAC) in 5/6 nephrectomized rats. An oral administration of low doses of SDACNFs (40mg/kg/day) over a 4 week period resulted in a significant decrease in serum indoxyl sulfate, creatinine and urea nitrogen levels, compared with a similar treatment with DAC or AST-120. The SDACNFs treatment also resulted in an increase in antioxidant potential, compared with that for DAC or AST-120. Immunohistochemical analyses also demonstrated that SDACNFs treated CRF rats showed a decrease in the amount of accumulated 8-OHdG compared with the CRF group. These results suggest that the ingestion of SDCH-NF results in a significant reduction in the levels of pro-oxidants, such as uremic toxins, in the gastrointestinal tract, thereby inhibiting the subsequent development of oxidative stress in the systemic circulation.

  4. Investigation of nano-structured Zirconium oxide film on Ti6Al4V substrate to improve tribological properties prepared by PIII&D

    Science.gov (United States)

    Saleem, Sehrish; Ahmad, R.; Ayub, R.; Ikhlaq, Uzma; Jin, Weihong; Chu, Paul K.

    2017-02-01

    Plasma immersion ion implantation and deposition (PIII&D) is the most attractive and efficient technique used in the medical field to tailor materials for biomedical applications. In the present study zirconium oxide nano-structured thin films were deposited on surface of Ti6Al4V alloy for bias voltages of 15, 20 and 25 kV. The chemical composition, surface roughness and thickness of deposited films were characterized by the x-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and ellipsometry respectively. The XPS results confirm the formation of a dense zirconium oxide film of the treated specimens. AFM results exhibit a smooth film with maximum roughness of about 8.4 nm is formed. The thickness of the film is increased with the increase in bias voltages and is maximum at 25 kV. The effect of bias voltages on wear characteristics was further investigated by pin-on-disk test. It is observed that the friction coefficient is reduced, whereas wear resistance is enhanced and it is found to be maximum at 25 kV compared to the other bias voltages. Nanohardness is improved up to twice compared to untreated specimen at the maximum bias voltage. Therefore, it is concluded that deposition of zirconium oxide using the PIII&D is produced a dense layer on the substrate surface, which can be used as a promising candidate for the improved tribological properties of Ti6Al4V.

  5. A novel non-enzymatic H{sub 2}O{sub 2} sensor based on polypyrrole nanofibers–silver nanoparticles decorated reduced graphene oxide nano composites

    Energy Technology Data Exchange (ETDEWEB)

    Moozarm Nia, Pooria, E-mail: pooriamn@yahoo.com; Lorestani, Farnaz, E-mail: farnaz.lorestani@siswa.um.edu.my; Meng, Woi Pei, E-mail: pmwoi@um.edu.my; Alias, Y., E-mail: yatimah70@um.edu.my

    2015-03-30

    Graphical abstract: - Highlights: • Decorating silver nanoparticles on the surface of graphene oxide nanocomposites. • Using and comparing two different electrochemical methods for reducing graphene oxide. • Investigating the effect of cyclic voltammetry and amperometry on electropolymerization of polypyrrole nanofibers. • The senor shows superior performances (LOD, LOQ, selectivity, repeatability, reproducibility and stability) towards H{sub 2}O{sub 2}. - Abstract: Graphene oxide (GO) decorated with silver nanoparticles (AgNPs), was electrochemically reduced on glassy carbon electrode (GCE) by an amperometry method (AMP-AgNPs-rGO/GCE). Then, Pyrrole was electropolymerized on the surface of the modified electrode through amperometry process in order to obtain nanofibers of polypyrrole (AMP-PpyNFs-AgNPs-rGO). Fourier-transform infrared transmission spectroscopy and X-ray diffraction approved that during the amperometry process, the GO and Ppy nanofibers were reduced and polymerized respectively and the silver nanoparticles were formed. Field emission scanning electron microscope images indicated that the silver nanoparticles were homogeneously distributed on the rGO surface with a narrow nano size distribution and polypyrrole synthesized in the form of nanofibers with diameter around 100 nm. The first linear section was in the range of 0.1–5 mM with a limit of detection of 1.099 and the second linear section raised to 90 mM with a correlation factor of 0.085 (S/N of 3)

  6. Origin of the Sudbury Complex by meteoritic impact: Neodymium isotopic evidence

    Science.gov (United States)

    Faggart, B.E.; Basu, A.R.; Tatsumoto, M.

    1985-01-01

    Samarium-neodymium isotopic data on whole rocks and minerals of the Sudbury Complex in Canada gave an igneous crystallization age of 1840 ?? 21 ?? 106 years. The initial epsilon neodymium values for 15 whole rocks are similar to those for average upper continental crust, falling on the crustal trend of neodymium isotopic evolution as defined by shales. The rare earth element concentration patterns of Sudbury rocks are also similar to upper crustal averages. These data suggest that the Sudbury Complex formed from melts generated in the upper crust and are consistent with a meteoritic impact.

  7. Nanostructured p-type semiconducting transparent oxides: promising materials for nano-active devices and the emerging field of "transparent nanoelectronics".

    Science.gov (United States)

    Banerjee, Arghya; Chattopadhyay, Kalyan K

    2008-01-01

    Transparent conducting oxides (TCO) with p-type semiconductivity have recently gained renewed interest for the fabrication of all-oxide transparent junctions, having potential applications in the emerging field of 'Transparent' or 'Invisible Electronics'. This kind of transparent junctions can be used as a "functional" window, which will transmit visible portion of solar radiation, but generates electricity by the absorption of the UV part. Therefore, these devices can be used as UV shield as well as UV cells. In this report, a brief review on the research activities on various p-TCO materials is furnished along-with the fabrication of different transparent p-n homojunction, heterojunction and field-effect transistors. Also the reason behind the difficulties in obtaining p-TCO materials and possible solutions are discussed in details. Considerable attention is given in describing the various patent generations on the field of p-TCO materials as well as transparent p-n junction diodes and light emitting devices. Also, most importantly, a detailed review and patenting activities on the nanocrystalline p-TCO materials and transparent nano-active device fabrication are furnished with considerable attention. And finally, a systematic description on the fabrication and characterization of nanocrystalline, p-type transparent conducting CuAlO(2) thin film, deposited by cost-effective low-temperature DC sputtering technique, by our group, is furnished in details. These p-TCO micro/nano-materials have wide range of applications in the field of optoelectronics, nanoelectronics, space sciences, field-emission displays, thermoelectric converters and sensing devices.

  8. Monitoring of the tumor response to nano-graphene oxide-mediated photothermal/photodynamic therapy by diffusion-weighted and BOLD MRI

    Science.gov (United States)

    Cao, Jianbo; An, Hengqing; Huang, Xinglu; Fu, Guifeng; Zhuang, Rongqiang; Zhu, Lei; Xie, Jin; Zhang, Fan

    2016-05-01

    Photothermal therapy (PTT) and photodynamic therapy (PDT) are promising cancer treatment modalities. Because each modality has its own set of advantages and limitations, there has been interest in developing methods that can co-deliver the two regimens for enhanced tumor treatment. Among the efforts, nano-graphene oxide-mediated phototherapies have recently attracted much attention. Nano-graphene oxide has a broad absorbance spectrum and can be loaded with photosensitizers, such as chlorin e6, with high efficiency. Chlorin e6-loaded and PEGylated nano-graphene (GO-PEG-Ce6) can be excited at 660 nm, 808 nm, or both, to induce PDT, PTT, or PDT/PTT combination. Despite the potential of the treatments, there is a lack of a diagnostic tool which can monitor their therapeutic response in a non-invasive and prognostic manner; such an ability is urgently needed for the transformation and translation of the technologies. In this study, we performed diffusion-weighted and blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) after GO-PEG-Ce6-mediated PTT, PDT, or PTT/PDT. We found that after efficient PTT, there is a significant increase of the tumor apparent diffusion coefficient (ADC) value in diffusion-weighted imaging (DWI) maps; meanwhile, an efficient PDT led to an increase of in BOLD images. In both the cases, the amplitude of the increase was correlated with the treatment outcomes. More interestingly, a synergistic treatment efficacy was observed when the PTT/PDT combination was applied, and the combination was associated with a greater ADC and increase than when either modality was used alone. In particular, the PTT/PDT condition that induced the most dramatic short-term increase of the ADC value (>70%) caused the most effective tumor control in the long-run, with 60% of the treated animals being tumor-free after 60 days. These results suggest the great promise of the combination of DWI and BOLD MRI as a tool for accurate monitoring and prognosis

  9. Analysis of the structure and Mössbauer study of the neodymium substitution in the Sr-hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Pérez-Juache, T.J. [Departamento de Ingeniería de Procesos e Hidráulica, Universidad Autónoma Metropolitana-Iztapalapa, A.P. 55-534, 09340 México D.F., México (Mexico); Guerrero, A.L., E-mail: azdlobo@gmail.com [Facultad de Ciencias, UASLP, Salvador Nava Martínez, s/n. Zona Universitaria, 78290 San Luis Potosí S.L.P., México (Mexico); Cabal-Velarde, J.G. [Instituto Tecnológico Superior de Irapuato, Carretera Irapuato-Silao Km. 12.5. Irapuato, Guanajuato, México (Mexico); Mirabal-García, M. [Instituto de Física, UASLP, Dr. Manuel Nava No. 6. Zona Universitaria, 78290 San Luis Potosí S.L.P., México (Mexico); Palomares-Sánchez, S.A. [Facultad de Ciencias, UASLP, Salvador Nava Martínez, s/n. Zona Universitaria, 78290 San Luis Potosí S.L.P., México (Mexico); Matutes-Aquino, J.A. [Centro de Investigación en Materiales Avanzados, Ave. Miguel de Cervantes 120, Complejo Industrial Chihuahua, 31109 Chihuahua, Ch. México, México (Mexico)

    2016-12-15

    This work reads on the obtainment of the strontium hexaferrite substituted with neodymium in its pure phase using the solid state reaction method. The solubility of neodymium on the strontium hexaferrite was investigated according with the formula Sr{sub 1−x}Nd{sub x}Fe{sub 12}O{sub 19}, for x=0.00, 0.05, 0.10, 0.15, 0.20 and 0.25. Results indicate that neodymium is soluble in the hexaferrite until x=0.15. In samples with higher neodymium content there are traces of secondary phases. Analysis of magnetic and structural properties was performed in function of the neodymium content, always in its solubility range. From the structural properties, it was observed that the addition of a little neodymium quantity in the Sr-hexaferrite causes an important reduction of the unit cell volume. Also, magnetic properties are strongly linked to the structural behavior, in this case a trend to reduce the magnetization of the samples was detected when neodymium content increased, which can be explained in terms of fluctuations of the superexchange coupling conducted by the neodymium interactions with the structure. Mössbauer analysis was carried out in order to analyze the effects of the neodymium substitution on the hyperfine parameters, as well as to confirm the preferential site of the neodymium substitution in the Sr-hexaferrite.

  10. Analysis of the structure and Mössbauer study of the neodymium substitution in the Sr-hexaferrite

    Science.gov (United States)

    Pérez-Juache, T. J.; Guerrero, A. L.; Cabal-Velarde, J. G.; Mirabal-García, M.; Palomares-Sánchez, S. A.; Matutes-Aquino, J. A.

    2016-12-01

    This work reads on the obtainment of the strontium hexaferrite substituted with neodymium in its pure phase using the solid state reaction method. The solubility of neodymium on the strontium hexaferrite was investigated according with the formula Sr1-xNdxFe12O19, for x=0.00, 0.05, 0.10, 0.15, 0.20 and 0.25. Results indicate that neodymium is soluble in the hexaferrite until x=0.15. In samples with higher neodymium content there are traces of secondary phases. Analysis of magnetic and structural properties was performed in function of the neodymium content, always in its solubility range. From the structural properties, it was observed that the addition of a little neodymium quantity in the Sr-hexaferrite causes an important reduction of the unit cell volume. Also, magnetic properties are strongly linked to the structural behavior, in this case a trend to reduce the magnetization of the samples was detected when neodymium content increased, which can be explained in terms of fluctuations of the superexchange coupling conducted by the neodymium interactions with the structure. Mössbauer analysis was carried out in order to analyze the effects of the neodymium substitution on the hyperfine parameters, as well as to confirm the preferential site of the neodymium substitution in the Sr-hexaferrite.

  11. Studies on characterization and removal of methylene blue with Delonix regia plant litters activated carbon encapsulated nano metal oxide.

    Science.gov (United States)

    Daniel, S; Syed Shabudeen, P S; Basker, A

    2015-07-01

    An advanced adsorbent material prepared by encapsulating nano-metaloxide on an activated carbon of Delonix regia plant litters was tested for its efficiency and superiority as an improved, advanced activated carbon material. It was subjected to modern instrumental techniques to evolve its morphology and its structure by FTIR, SEM, TEM, XRD, EDAX and BET studies. The size of MgO particles was in the range of 20 nm-25 nm. The surface area of nano composite was 632 m2 g(-1). Experimental results, based on batch mode of experiments, indicated that the adsorbent could remove 90% dye for the adsorbent dosage of 100 mg, at pH 7.0 and contact time of 120 min. The adsorption equilibrium data were well correlated for both, Langmuir and Freundlich isotherms. The monolayer adsorption capacity Qo was found to be 14.425 mg g(-1) for the composite. The kinetic adsorption data fitted the pseudo first order modeled by Lagergren and also intra particle diffusion. Removal efficiency of the composite adsorbent was higher than the uncoated adsorbents. Regeneration of exhausted adsorbent showed considerable improved variation in comparison to normal activated carbon materials.

  12. Iron oxide functionalized graphene nano-composite for dispersive solid phase extraction of chemical warfare agents from aqueous samples.

    Science.gov (United States)

    Chinthakindi, Sridhar; Purohit, Ajay; Singh, Varoon; Tak, Vijay; Goud, D Raghavender; Dubey, D K; Pardasani, Deepak

    2015-05-15

    Present study deals with the preparation and evaluation of graphene based magnetic nano-composite for dispersive solid phase extraction of Chemical Weapons Convention (CWC) relevant chemicals from aqueous samples. Nano-composite, Fe3O4@SiO2-G was synthesized by covalently bonding silica coated Fe3O4 onto the graphene sheets. Nerve agents (NA), Sulfur mustard (SM) and their non-toxic environmental markers were the target analytes. Extraction parameters like amount of sorbent, extraction time and desorption conditions were optimized. Dispersion of 20 milligram of sorbent in 200mL of water sample for 20min. followed by methanol/chloroform extraction produced average to good recoveries (27-94%) of targeted analytes. Recoveries of real agents exhibited great dependency upon sample pH and ionic strength. Sarin produced maximum recovery under mild acidic conditions (56% at pH 5) while VX demanded alkaline media (83% at pH 9). Salts presence in the aqueous samples was found to be advantageous, raising the recoveries to as high as 94% for SM. Excellent limits of detection (LOD) for sulphur mustard and VX (0.11ngmL(-1) and 0.19ngmL(-1) respectively) proved the utility of the developed method for the off-site analysis of CWC relevant chemicals.

  13. 纳米氧化锌致细胞凋亡的机制研究%Mechanism of nano-zinc oxide-induced apoptosis

    Institute of Scientific and Technical Information of China (English)

    杨通旺; 张博闻; 吴涛; 吴刚

    2016-01-01

    Objective To explore the rule of oxidative stress which introduced by nano-zinc oxide between autophagy and apoptosis in non-small cell lung cancer(H1299)cells line.Methods The study were divided into experimental and control groups.The control group was given normal medium, and the experimental groups were given different dose of nano-zinc oxide(2.5,10 and 25μg/ml).The GFP-LC3 plasmid were translated into the cells, green fluorescent spots were considered autophagosome.LC3-Ⅱwhich is the biomarker of the autohagosome was detected by Western blotting.The living and late apoptosis cells were detected by Calcein AM and PI stain, respectively.The accumulation of intracellular reactive oxygen species(ROS)was detected by DHE.The dispersed state of the nano-zinc oxide was detected by dynamic light scattering in the medium.Results There were little cells stained to red by the DHE and accumulated with green fluorescent spots,but the cells were not stained to red by PI.The cells which stained to red by the DHE increased,green fluorescent spots were accumulated in the low-dose group,and there were some cells stained to red by PI.The majority of the cells were stained to red by the DHE,green fluorescent spots were accumulated in both the medium and high dose groups,and the cells were stained to red by the PI at the same time.The nano-zinc oxide was dispersed well in the medium.Conclusions The disorder of the autophagy that caused by the oxidative stress which induced by the nano-zinc oxide lead apoptosis in the H1299 cells line.%目的 研究氧化应激在纳米氧化锌引起的人非小细胞肺癌细胞(H1299)细胞自噬和凋亡之间的作用.方法 实验分为实验组和对照组,对照组给予正常的培养基而实验组在培养基中分别给予2.5、10和25μg/ml(低,中,高剂量组)浓度的纳米氧化锌.向细胞中转染绿色荧光蛋白-微管相关蛋白1轻链3(GFP-LC3)质粒,通过观察绿色荧光斑点确定自噬的发生.Western blotting

  14. Accurate measurement of neodymium isotopic composition using Neptune MC-ICP-MS

    Institute of Scientific and Technical Information of China (English)

    Yueheng YANG; Hongfu ZHANG; Liewen XIE; Fuyuan WU

    2008-01-01

    This paper reports the measurement of the Neodymium isotopic composition by Neptune Multiple Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS) over the last two years. Although there is concomitant Cerium in the chemical separation process, this has no significant influence on the Neodymium analysis. As for the sample containing small amounts of Samarium (Sm/Nd<0.04), direct calibration for isobaric interference and mass discrimina-tion by the exponential law can be obtained by assuming that Samarium mass discrimination is the same as that of Neodymium. Geological samples after traditional chemi-cal separation were measured by Neptune MC-ICP-MS and Thermal Ionization Mass Spectrometry (TIMS) respectively. The results show that Neptune MC-ICP-MS can measure Neodymium isotopic composition as precisely the TIMS does and is even more effective and less time-consuming than the TIMS Method.

  15. Description of the traction characteristics of the neodymium compensators of the automatic vibration isolations

    Science.gov (United States)

    Gurova, E. G.; Panchenko, Y. V.; Gurov, M. G.

    2016-04-01

    In this paper the method of calculation of neodymium magnets was presented. The calculation of the neodymium magnets characteristics and stiffness correctors of the vibration isolator according to the requirements for vibration isolation devices with stiffness compensators was performed. This research has been performed with the support of the President scholarship for young scientists, order No. 184 of Ministry of education and science of the Russian Federation of the 10th of March 2015.

  16. Neodymium and strontium isotope evidence for crustal contamination of continental volcanics.

    Science.gov (United States)

    Carter, S R; Evensen, N M; Hamilton, P J; O'nions, R K

    1978-11-17

    Combined neodymium and strontium isotope studies on Tertiary volcanics from northwest Scotland indicate that their parental mantle isotopic compositions have been substantially modified in many instances by contamination with the Precambrian continental crust through which they were erupted. The occurrence of samarium-neodymium and rubidium-strontium "pseudoisochrons" of different ages in these contaminated continental volcanics indicates that they are artifacts of the contamination processes and have no temporal significance with respect to mantle fractionation events.

  17. Nano-sized glass as an economically viable and eco-benign support to anchor heteropolyacids for green and sustainable chemoselective oxidation of sulfides to sulfoxides

    Indian Academy of Sciences (India)

    SOMAYEH ZOLFAGHARINIA; ESKANDAR KOLVARI; NADIYA KOUKABI; MALIHEH M HOSSEINI

    2017-09-01

    In this work, glass wastes were employed as cost-effective supports for the immobilization of phosphomolybdic acid (5–25 wt.% PMA) through an impregnation method. The highly efficient and retrievable nanocatalyst named nano-glass waste-supported phosphomolybdic acid (n-GW/PMA) was fully characterized by several techniques such as: XRD, FE-SEM, EDX, FT-IR and TGA. The catalytic performance of the assynthesized heterogeneous nanocatalystwas effectively investigated for the chemoselective oxidation of sulfides to sulfoxides in the presence of 30% H₂O₂ as an oxidant at room temperature under solvent-free condition. Optimization of the reaction conditions was performed by means of central composite design (CCD), which isone of the powerful response surface methodologies. Based on the results obtained under the optimum condition, the sample of 16 wt.% of PMA loading offered high conversion rates and yields (97%). Besides, the beneficialpoints of the prepared catalyst were its recoverability and reusability for several reaction cycles, low-cost and toxicity, easy availability and facile production.

  18. In situ derivation of sulfur activated TiO{sub 2} nano porous layers through pulse-micro arc oxidation technology

    Energy Technology Data Exchange (ETDEWEB)

    Bayati, M.R., E-mail: mbayati@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States); School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Golestani-Fard, F. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Center of Excellence for Advanced Materials, Iran University of Science and Technology, P.O. Box 16845-195, Tehran (Iran, Islamic Republic of); Moshfegh, A.Z. [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-89694, Tehran (Iran, Islamic Republic of); Molaei, Roya [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of)

    2011-10-15

    Highlights: {yields} S-TiO{sub 2} layers were grown by MAO technique under pulse current for the first time. {yields} Effect of growth parameters on chemical composition, topography, and morphology of the layers was studied. {yields} A correlation between photocatalytic performance and growth conditions was proposed. -- Abstract: Micro arc oxidation technique, as a facile and efficient process, was employed to grow sulfur doped titania porous layers. This research sheds light on the photocatalytic performance of the micro arc oxidized S-TiO{sub 2} nano-porous layers fabricated under pulse current. Morphological and topographical studies, performed by SEM and AFM techniques, revealed that increasing the frequency and/or decreasing the duty cycle resulted in formation of finer pores and smoother surfaces. XRD and XPS results showed that the layers consisted of anatase and rutile phases whose fraction was observed to change depending on the synthesis conditions. The highest anatase relative content was obtained at the frequency of 500 Hz and the duty cycle of 5%. Furthermore, photocatalytic activity of the layers was examined by measuring the decomposition rate of methylene blue under both ultraviolet and visible photo irradiations. Maximum photodegradation reaction rate constants over the pulse-grown S-TiO{sub 2} layers were respectively measured as 0.0202 and 0.0110 min{sup -1} for ultraviolet and visible irradiations.

  19. Influence of nano-Al2O3-reinforced oxide-dispersion-strengthened Cu on the mechanical and tribological properties of Cu-based composites

    Science.gov (United States)

    Zhao, Xiang; Guo, Lei-chen; Zhang, Long; Jia, Ting-ting; Chen, Cun-guang; Hao, Jun-jie; Shao, Hui-ping; Guo, Zhi-meng; Luo, Ji; Sun, Jun-bin

    2016-12-01

    The mechanical and tribological properties of Cu-based powder metallurgy (P/M) friction composites containing 10wt%-50wt% oxide-dispersion-strengthened (ODS) Cu reinforced with nano-Al2O3 were investigated. Additionally, the friction and wear behaviors as well as the wear mechanism of the Cu-based composites were characterized by scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDS) elemental mapping. The results indicated that the Cu-based friction composite containing 30wt% ODS Cu exhibited the highest hardness and shear strength. The average and instantaneous friction coefficient curves of this sample, when operated in a high-speed train at a speed of 300 km/h, were similar to those of a commercial disc brake pad produced by Knorr-Bremse AG (Germany). Additionally, the lowest linear wear loss of the obtained samples was (0.008 ± 0.001) mm per time per face, which is much lower than that of the Knorr-Bremse pad ((0.01 ± 0.001) mm). The excellent performance of the developed pad is a consequence of the formation of a dense oxide composite layer and its close combination with the pad body.

  20. Perovskite catalysts for oxidative coupling

    Science.gov (United States)

    Campbell, Kenneth D.

    1991-01-01

    Perovskites of the structure A.sub.2 B.sub.2 C.sub.3 O.sub.10 are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  1. Research and development of neodymium phosphate laser glass for high power laser application

    Science.gov (United States)

    Hu, Lili; He, Dongbing; Chen, Huiyu; Wang, Xin; Meng, Tao; Wen, Lei; Hu, Junjiang; Xu, Yongchun; Li, Shunguang; Chen, Youkuo; Chen, Wei; Chen, Shubin; Tang, Jingping; Wang, Biao

    2016-12-01

    Neodymium phosphate laser glass is a key optical element for high-power laser facility. In this work, the latest research and development of neodymium phosphate laser glass at the Shanghai Institute of Optics and Fine Mechanics (SIOM), China, is addressed. Neodymium phosphate laser glasses, N31, N41, NAP2, and NAP4, for high peak power and high average power applications have been developed. The properties of these glasses are presented and compared to those of other commercial neodymium phosphate laser glass from the Schott and Hoya companies and the Vavilov State Optical Institute (GOI), Russia. Continuous melting and edge cladding are the two key fabrication techniques that are used for the mass production of neodymium phosphate laser glass slabs. These techniques for the fabrication of large-aperture N31 neodymium phosphate laser glass slabs with low stress birefringence and residual reflectivity have been developed by us The effect of acid etching on the microstructure, optical transmission, and mechanical properties of NAP2 glass is also discussed.

  2. Determination of neodymium, holmium and erbium in mixed rare earths by norfloxacin

    Energy Technology Data Exchange (ETDEWEB)

    Wang Nai-Xing; Jiang Wei; Ren Yuezhen; Si Zhikun; Qiu Xunxing [Department of Chemistry, Shandong University, Jinan (China); Wang Lei [Department of Pharmacy, Shandong Medical University, Jinan (China); Du Gaoying; Qi Ping [Shandong Analysis and Test Center, Jinan (China)

    1998-08-01

    Norfloxacin (NFX) is proposed as reagent for the derivative spectrophotometric determination of neodymium, holmium and erbium in mixed rare earths. The absorption spectra of 4f electron transitions of the systems of neodymium, holmium and erbium complexes with norfloxacin in presence of cetylpyridinium chloride were studied by normal and derivative spectra. The absorption bands found normally at 575 nm for neodymium, 450 nm for holmium and 523 nm for erbium were enhanced markedly. Using the second derivative spectrum, Beer`s Law is obeyed from 5.0 x 10{sup -5} {proportional_to} 2.5 x 10{sup -4} mol dm{sup -3} for neodymium, holmium and erbium. The relative standard deviations are 1.0, 1.4 and 1.1% for 6.9 x 10{sup -5} mol dm{sup -3} of neodymium, 6.1 x 10{sup -5} mol dm{sup -3} of holmium and 6.0 x 10{sup -5} mol dm{sup -3} of erbium, respectively. A method for the direct determination of neodymium, holmium and erbium in mixtures of rare earth elements with good accuracy and selectivity, is described. (orig.) With 4 figs., 2 tabs., 11 refs.

  3. Research and development of neodymium phosphate laser glass for high power laser application

    Science.gov (United States)

    Hu, Lili; He, Dongbing; Chen, Huiyu; Wang, Xin; Meng, Tao; Wen, Lei; Hu, Junjiang; Xu, Yongchun; Li, Shunguang; Chen, Youkuo; Chen, Wei; Chen, Shubin; Tang, Jingping; Wang, Biao

    2017-01-01

    Neodymium phosphate laser glass is a key optical element for high-power laser facility. In this work, the latest research and development of neodymium phosphate laser glass at the Shanghai Institute of Optics and Fine Mechanics (SIOM), China, is addressed. Neodymium phosphate laser glasses, N31, N41, NAP2, and NAP4, for high peak power and high average power applications have been developed. The properties of these glasses are presented and compared to those of other commercial neodymium phosphate laser glass from the Schott and Hoya companies and the Vavilov State Optical Institute (GOI), Russia. Continuous melting and edge cladding are the two key fabrication techniques that are used for the mass production of neodymium phosphate laser glass slabs. These techniques for the fabrication of large-aperture N31 neodymium phosphate laser glass slabs with low stress birefringence and residual reflectivity have been developed by us The effect of acid etching on the microstructure, optical transmission, and mechanical properties of NAP2 glass is also discussed.

  4. Evaluating United States and world consumption of neodymium, dysprosium, terbium, and praseodymium in final products

    Science.gov (United States)

    Hart, Matthew

    This paper develops scenarios of future rare-earth-magnet metal (neodymium, dysprosium, terbium, and praseodymium) consumption in the permanent magnets used in wind turbines and hybrid electric vehicles. The scenarios start with naive base-case scenarios for growth in wind-turbine and hybrid-electric-vehicle sales over the period 2011 to 2020, using historical data for each good. These naive scenarios assume that future growth follows time trends in historical data and does not depend on any exogenous variable. Specifically, growth of each technological market follows historical time trends, and the amount of rare earths used per unit of technology remains fixed. The chosen reference year is 2010. Implied consumptions of the rare earth magnet metals are calculated from these scenarios. Assumptions are made for the material composition of permanent magnets, the market share of permanent-magnet wind turbines and vehicles, and magnet weight per unit of technology. Different scenarios estimate how changes in factors like the material composition of magnets, growth of the economy, and the price of a substitute could affect future consumption. Each scenario presents a different method for reducing rare earth consumption and could be interpreted as potential policy choices. In 2010, the consumption (metric tons, rare-earth-oxide equivalent) of each rare-earth-magnet metal was as follows. Total neodymium consumption in the world for both technologies was 995 tons; dysprosium consumption was 133 tons; terbium consumption was 50 tons; praseodymium consumption was zero tons. The base scenario for wind turbines shows there could be strong, exponential growth in the global wind turbine market. New U.S. sales of hybrid vehicles would decline (in line with the current economic recession) while non-U.S. sales increase through 2020. There would be an overall increase in the total amount of magnetic rare earths consumed in the world. Total consumption of each rare earth in the short

  5. TEM and AES investigations of the natural surface nano-oxide layer of an AISI 316L stainless steel microfibre.

    Science.gov (United States)

    Ramachandran, Dhanya; Egoavil, Ricardo; Crabbe, Amandine; Hauffman, Tom; Abakumov, Artem; Verbeeck, Johan; Vandendael, Isabelle; Terryn, Herman; Schryvers, Dominique

    2016-11-01

    The chemical composition, nanostructure and electronic structure of nanosized oxide scales naturally formed on the surface of AISI 316L stainless steel microfibres used for strengthening of composite materials have been characterised using a combination of scanning and transmission electron microscopy with energy-dispersive X-ray, electron energy loss and Auger spectroscopy. The analysis reveals the presence of three sublayers within the total surface oxide scale of 5.0-6.7 nm thick: an outer oxide layer rich in a mixture of FeO.Fe2 O3 , an intermediate layer rich in Cr2 O3 with a mixture of FeO.Fe2 O3 and an inner oxide layer rich in nickel.

  6. Effective improvement of interface modified strontium titanate based solid oxide fuel cell anodes by infiltration with nano-sized palladium and gadolinium-doped cerium oxide

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain; Høgh, Jens Valdemar Thorvald; Zhang, Wei

    2013-01-01

    The development of low temperature solid oxide fuel cell (SOFC) anodes by infiltration of Pd/Gd-doped cerium oxide (CGO) electrocatalysts in Nb-doped SrTiO3 (STN) backbones has been investigated. Modification of the electrode/electrolyte interface by thin layer of spin-coated CGO (400-500 nm) con...

  7. Biological Activity and Antibacterial Property of Nano-structured TiO2 Coating Incorporated with Cu Prepared by Micro-arc Oxidation

    Institute of Scientific and Technical Information of China (English)

    Wei Zhu; Zhenxiang Zhang; Beibei Gu; Junying Sun; Lixian Zhu

    2013-01-01

    Micro-arc oxidized Cu-incorporated TiO2 coatings (Cu-TiO2) were prepared in the Ca,P,Cu-containing electrolyte to obtain an implant material with superior biological activity and antibacterial property.The surface topography,phase,and element composition of the TiO2 and Cu-TiO2 coatings were characterized by scanning electron microscopy (SEM),X-ray diffraction (XRD),and energy-dispersive X-ray spectrometry (EDS),respectively.Staphylococcus aureus (S.aureus) was selected to evaluate the antibacterial property of the Cu-TiO2 coatings,whereas osteoblastic MG63 cells were cultured on the coatings to investigate the biological activity.The obtained results demonstrated that Cu element was successfully incorporated into the porous nano-structured TiO2 coatings,which did not alter apparently the surface topography and phase composition of the coatings as compared to the Cu-free TiO2 coatings.Moreover,the antibacterial studies suggested that the Cu-incorporated TiO2 coatings could significantly inhibit the adhesion of S.aureus.In addition,the in vitro biological evaluation displayed that the adhesion,proliferation and differentiation of MG63 cells on the Cu-incorporated coatings were enhanced as compared to those on the Cu-free coatings and Ti plates.In conclusion,the innovative Cu-incorporated nano-structured TiO2 coatings on Ti substrate with excellent antibacterial property and biological activity are promising candidates for orthopedic implant.

  8. FeMnMg氧化物Fenton催化降解有机废水%Research of FeMnMg Oxide Nano Particles Fenton-Degraded Methylene Blue

    Institute of Scientific and Technical Information of China (English)

    贾若琨; 李佳

    2014-01-01

    采用高温煅烧硝化法制备FeMnMg氧化物纳米晶,并采用扫描电镜( SEM)对FeMnMg氧化物进行表征。结果表明,高温煅烧硝化法制备的FeMnMg氧化物粒径为纳米范围,具有均匀的粒子尺寸和晶体尺寸。采用不同配比的FeMnMg氧化物纳米晶催化剂对亚甲基蓝模拟的有机废水进行Fenton催化降解实验,对实验结果进行分析讨论。 FeMnMg的摩尔比为2∶3∶1的氧化物对亚甲基蓝的降解效果最好。当pH值为7左右,反应温度为25℃时,降解速率最快。 FeMnMg 氧化物催化剂的投加量为0.012 g,保证了亚甲基蓝较好的降解率。在反应体系中采用选取30% H2O20.5 mL(即2 mmol/L),能达到较好的氧化降解效果。%FeMnMg oxide nanocrystals were prepared by a high temperature calcination method,and they were characterized by scanning electron microscope ( SEM ) . The results showed that FeMnMg oxide nanocrystals prepared with temperature calcination method were nano particle size range, and the FeMnMg oxide nanocrystals had uniform particle size and crystallite size. The strong H2 O2-activating ability of FeMnMg oxide nanocrystals showed promising applications in the oxidative degradation of organic pollutants methylene blue. Using the best catalyst of degradation effect of methylene blue in the experiments,carried on the optimal Fenton catalytic conditions on the exploring experiment. We studied the dosing quantity of catalyst FeMnMg oxide nanocrystals,the addition content of H2 O2 ,pH value and reaction temperature effect influence on catalytic deg-radation of methylene blue solution.

  9. Extremely fine structured cathode for solid oxide fuel cells using Sr-doped LaMnO3 and Y2O3-stabilized ZrO2 nano-composite powder synthesized by spray pyrolysis

    Science.gov (United States)

    Shimada, Hiroyuki; Yamaguchi, Toshiaki; Sumi, Hirofumi; Nomura, Katsuhiro; Yamaguchi, Yuki; Fujishiro, Yoshinobu

    2017-02-01

    A solid oxide fuel cell (SOFC) for high power density operation was developed with a microstructure-controlled cathode using a nano-composite powder of Sr-doped LaMnO3 (LSM) and Y2O3-stabilized ZrO2 (YSZ) synthesized by spray pyrolysis. The individual LSM-YSZ nano-composite particles, formed by crystalline and amorphous nano-size LSM and YSZ particles, showed spherical morphology with uniform particle size. The use of this powder for cathode material led to an extremely fine microstructure, in which all the LSM and YSZ grains (approximately 100-200 nm) were highly dispersed and formed their own network structures. This microstructure was due to the two phase electrode structure control using the powder, namely, nano-order level in each particle and micro-order level between particles. An anode-supported SOFC with the LSM-YSZ cathode using humidified H2 as fuel and ambient air as oxidant exhibited high power densities, such as 1.29 W cm-2 under a voltage of 0.75 V and a maximum power density of 2.65 W cm-2 at 800 °C. Also, the SOFC could be stably operated for 250 h with no degradation, even at a high temperature of 800 °C.

  10. Antimicrobial, free radical scavenging activities and catalytic oxidation of benzyl alcohol by nano-silver synthesized from the leaf extract of Aristolochia indica L.: a promenade towards sustainability

    Science.gov (United States)

    Shanmugam, C.; Sivasubramanian, G.; Parthasarathi, Bera; Baskaran, K.; Balachander, R.; Parameswaran, V. R.

    2016-06-01

    Silver nanoparticles (Ag-NPs) were synthesized from aqueous silver nitrate through a simple route using the leaf extract of Aristolochia indica L. (LAIL) which acted as a reducing as well as capping agent. X-ray diffraction confirmed that the synthesized silver particles have a face centred cubic structure. EDS predicted the presence of elemental silver. The SEM images showed the synthesis of spherically mono-dispersed particles, with nano dimensions accounted by the TEM images. Infra-red spectrum adopted to the different organic functionalities present at the surface of the particles. TGA indicated an overall 11 % weight loss up to 1000 °C, suggesting desorption of biomolecules from the surface. X-ray photoelectron spectroscopy (XPS) analysis revealed the presence of metallic silver nanoparticles. The prepared material was utilized as catalyst in the oxidation of benzyl alcohol with molecular oxygen as the oxidant in methanol, under ambient conditions of temperature and pressure. Also Ag-NPs showed good to moderate anti-microbial activity employing the Agar disc diffusion method against various strains using Ciprofloxacin and Fluconazole as standard. Free radical scavenging activity of the nanoparticles were observed by modified 1,1-diphynyl-2-picrylhydrazyl, DPPH and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), ABTS in vitro assays. The work presented here demonstrates the adaptability of the synthesized Ag-NPs in participating as a disinfectant agent, free radical scavenger and an effective oxidation catalyst. The basic premise of attaining sustainability through the green synthesis of smart multifaceted materials has been consciously addressed.

  11. Thermoluminescent sensitivity of single clad neodymium doped SiO2 optical fibres measured with 6 MeV photons

    Science.gov (United States)

    Saeed, M. A.; Hossain, I.; Hida, N.; Wagiran, H.

    2013-10-01

    This study investigates the thermoluminescent sensitivity of neodymium doped SiO2 optical fibre with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MeV photon irradiations. The TL responses of the neodymium doped silica fibres are compared with available TLD-100 dosimeter in order to determine the suitability as a TL material. We found that the TLD-100 and neodymium doped silica fibre have a significant linear signal to dose relationship. Neodymium doped fibres sensitivity is approximately 11% of TLD-100.

  12. Template-assisted synthesis of III-nitride and metal-oxide nano-heterostructures using low-temperature atomic layer deposition for energy, sensing, and catalysis applications (Presentation Recording)

    Science.gov (United States)

    Biyikli, Necmi; Ozgit-Akgun, Cagla; Eren, Hamit; Haider, Ali; Uyar, Tamer; Kayaci, Fatma; Guler, Mustafa Ozgur; Garifullin, Ruslan; Okyay, Ali K.; Ulusoy, Gamze M.; Goldenberg, Eda

    2015-08-01

    Recent experimental research efforts on developing functional nanostructured III-nitride and metal-oxide materials via low-temperature atomic layer deposition (ALD) will be reviewed. Ultimate conformality, a unique propoerty of ALD process, is utilized to fabricate core-shell and hollow tubular nanostructures on various nano-templates including electrospun nanofibrous polymers, self-assembled peptide nanofibers, metallic nanowires, and multi-wall carbon nanotubes (MWCNTs). III-nitride and metal-oxide coatings were deposited on these nano-templates via thermal and plasma-enhanced ALD processes with thickness values ranging from a few mono-layers to 40 nm. Metal-oxide materials studied include ZnO, TiO2, HfO2, ZrO2, and Al2O3. Standard ALD growth recipes were modified so that precursor molecules have enough time to diffuse and penetrate within the layers/pores of the nano-template material. As a result, uniform and conformal coatings on high-surface area nano-templates were demonstrated. Substrate temperatures were kept below 200C and within the self-limiting ALD window, so that temperature-sensitive template materials preserved their integrity III-nitride coatings were applied to similar nano-templates via plasma-enhanced ALD (PEALD) technique. AlN, GaN, and InN thin-film coating recipes were optimized to achieve self-limiting growth with deposition temperatures as low as 100C. BN growth took place only for >350C, in which precursor decomposition occured and therefore growth proceeded in CVD regime. III-nitride core-shell and hollow tubular single and multi-layered nanostructures were fabricated. The resulting metal-oxide and III-nitride core-shell and hollow nano-tubular structures were used for photocatalysis, dye sensitized solar cell (DSSC), energy storage and chemical sensing applications. Significantly enhanced catalysis, solar efficiency, charge capacity and sensitivity performance are reported. Moreover, core-shell metal-oxide and III-nitride materials

  13. EMISSION REDUCTION FROM A DIESEL ENGINE FUELED BY CERIUM OXIDE NANO-ADDITIVES USING SCR WITH DIFFERENT METAL OXIDES COATED CATALYTIC CONVERTER

    Directory of Open Access Journals (Sweden)

    B. JOTHI THIRUMAL

    2015-11-01

    Full Text Available This paper reports the results of experimental investigations on the influence of the addition of cerium oxide in nanoparticle form on the major physiochemical properties and the performance of diesel. The fuel is modified by dispersing the catalytic nanoparticle by ultrasonic agitation. The physiochemical properties of sole diesel fuel and modified fuel are tested with ASTM standard procedures. The effects of the additive nanoparticles on the individual fuel properties, the engine performance, and emissions are studied, and the dosing level of the additive is optimized. Cerium oxide acts as an oxygen-donating catalyst and provides oxygen for the oxidation of CO during combustion. The active energy of cerium oxide acts to burn off carbon deposits within the engine cylinder at the wall temperature and prevents the deposition of non-polar compounds on the cylinder wall which results in reduction in HC emission by 56.5%. Furthermore, a low-cost metal oxide coated SCR (selective catalyst reduction, using urea as a reducing agent, along with different types of CC (catalytic converter, has been implemented in the exhaust pipe to reduce NOx. It was observed that a reduction in NOx emission is 50–60%. The tests revealed that cerium oxide nanoparticles can be used as an additive in diesel to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

  14. PREPARATION AND CHARACTERIZATION OF STRONTIUM FLUORIDE POWDERS ACTIVATED BY NEODYMIUM FLUORIDE

    Directory of Open Access Journals (Sweden)

    S. V. Kuznetsov

    2015-07-01

    Full Text Available Subject of Study. The paper deals with preparation processes of ultradisperse, homogeneous powder Sr1-хNdхF2+х (х= 0.003-0.2, with use of ammonium fluoride as the fluorinating agent taken over 114-120 % from stoichiometry. Method. Nitrate of strontium, neodymium nitrate hexahydrate, with the content equal to 99. 99 % of the basic substance and ammonium fluoride were used as the source of substances. Activated powders of strontium fluoride were obtained by the method of deposition from aqueous solutions by washing the precipitate with a solution of ammonium fluoride, taken over 114 - 120% from stoichiometry. The washed precipitate was centrifuged for 5-7 min, dried in the air at 30-350 C. Heat treatment of the dried precipitate was carried out in two stages: the first stage at the temperature of 200- 2500 C for 0.5-1 hour, the second one at 550- 6000 C for 2-3 hours. X-ray analysis of the synthesized samples was carried out on a Bruker D8 Advance diffractometer, radiation Cu K. The size and shape measuring of the particles of activated strontium fluoride was carried out by means of electron microscope Carl Zeiss NVision 40. The content of neodymium in activated powders of strontium fluoride was determined by the method of spectral emission analysis on the device LEA - S500. Chemical analysis for determination of ammonium ion (NH4+ content in the obtained samples was performed by the method of Kjeldahl. Calculations of lattice parameters, size of coherent scattering regions and the values of micro-deformations were carried out by TOPAS program. Main Results. Preparation processes of ultradisperse, homogeneous powder Sr1-хNdхF2+х (х= 0.003-0.2, with use of ammonium fluoride as the fluorinating agent taken over 114-120 % from stoichiometry, provides obtaining the firm solution Sr1-x-yNdx(NH4yF2+x-y of the cubic fluorite structure. It has been found out that the morphology and size of the resulting product depend on the quantity of

  15. A Novel Route to Synthesize Nano-crystalline Ba0.5Sr0.5Co0.8Fe0.2O3-δ Perovskite Oxide at High Temperature

    Institute of Scientific and Technical Information of China (English)

    Wei ZHOU; Zong Ping SHAO; Wan Qin JIN

    2006-01-01

    It is normally difficult to prepare nano-sized Ba0.5Sr0.5Co0.8Fe0.2O3-δ(BSCF) oxide at high temperature due to its high surface activity. The complexing process, which has successfully applied in the synthesis of nano Sm0.15Ce0.85O1.925 with crystallite size down to 5 nm1, just resulted in a coarse BSCF with crystallite size of 41.9 nm at 900℃. We applied a novel process by simply modifying the solid precursor from the complexing process with concentrated nitric acid treatment.The obtained BSCF powder had a crystallite size of ~25 nm even calcined at 1000C. The small crystallite size is extremely promising to enhance the electrochemical performance of cathode for solid oxide fuel cell dramatically.

  16. Synthesis and Characterisation of Nano Lanthana

    Science.gov (United States)

    Moothedan, Marymol; Sherly, K. B.

    2011-10-01

    Nano sized oxide materials have gained an immense importance due to their unque electrical and magnetic properties. Nano Lanthana has various applications in solide oxide fuel cells, catalytic exhaust gas converters, magnetic data storage, water treatment and also as a nano catalyst. The performance of the nano Lanthana depends on the particle size, morphology, crystalline nature etc which in tern depends on the method of preparation and pre-treatment conditions. In this study nano Lanthana was prepared by using the natural polymer Starch as the template. The effect of reaction condition and concentration of starch on the formation, particle size, crystalline nature, and morphology of nano lanthana was also investigated. The phase composition, crystallinine character and particle size were obtained from XRD. The surface morphology of the prepared sample was investigated by SEM. Elemental analysis using SEM-EDAX confirmed the stochiometry of the sample..

  17. High performance nano-Ni/Graphite electrode for electro-oxidation in direct alkaline ethanol fuel cells

    Science.gov (United States)

    Soliman, Ahmed B.; Abdel-Samad, Hesham S.; Abdel Rehim, Sayed S.; Ahmed, Mohamed A.; Hassan, Hamdy H.

    2016-09-01

    Ni/Graphite electrocatalysts (Ni/G) are successfully prepared through electrodeposition of Ni from acidic (pH = 0.8) and feebly acidic (pH = 5.5) aqueous Ni (II) baths. The efficiencies of such electrodes are investigated as anodes for direct alkaline ethanol fuel cells through their ethanol electrooxidation cyclic voltammetric (CV) response in alkaline medium. A direct proportionality between the amount of the electrodeposited Ni and its CV response is found. The amounts of the deposited Ni from the two baths are recorded using the Electrochemical Quartz Crystal Microbalance (eQCM). The Ni/G electrodes prepared from the feebly acidic bath show a higher electrocatalytic response than those prepared from the acidic bath. Surface morphology of the Ni particles electrodeposited from feebly acidic bath appears in a nano-scale dimension. Various electrochemical experiments are conducted to confirm that the Ni/G ethanol electrooxidation CV response greatly depends on the pH rather than nickel ion concentration of the deposition bath. The eQCM technique is used to detect the crystalline phases of nickel as α-Ni(OH)2/γ-NiOOH and β-Ni(OH)2/β-NiOOH and their in-situ inter-transformations during the potentiodynamic polarization.

  18. Catalytic Upgrading of Biomass Fast Pyrolysis Vapors with Nano Metal Oxides: An Analytical Py-GC/MS Study

    Directory of Open Access Journals (Sweden)

    Qiang Lu

    2010-11-01

    Full Text Available Fast pyrolysis of poplar wood followed with catalytic cracking of the pyrolysis vapors was performed using analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS. The catalysts applied in this study were nano MgO, CaO, TiO2, Fe2O3, NiO and ZnO. These catalysts displayed different catalytic capabilities towards the pyrolytic products. The catalysis by CaO significantly reduced the levels of phenols and anhydrosugars, and eliminated the acids, while it increased the formation of cyclopentanones, hydrocarbons and several light compounds. ZnO was a mild catalyst, as it only slightly altered the pyrolytic products. The other four catalysts all decreased the linear aldehydes dramatically, while the increased the ketones and cyclopentanones. They also reduced the anhydrosugars, except for NiO. Moreover, the catalysis by Fe2O3 resulted in the formation of various hydrocarbons. However, none of these catalysts except CaO were able to greatly reduce the acids.

  19. Organ burden and pulmonary toxicity of nano-sized copper (II) oxide particles after short-term inhalation exposure

    NARCIS (Netherlands)

    Gosens, Ilse; Cassee, Flemming R|info:eu-repo/dai/nl/143038990; Zanella, Michela; Manodori, Laura; Brunelli, Andrea; Costa, Anna Luisa; Bokkers, Bas G H|info:eu-repo/dai/nl/304847062; de Jong, Wim H; Brown, David; Hristozov, Danail; Stone, Vicki

    2016-01-01

    INTRODUCTION: Increased use of nanomaterials has raised concerns about the potential for undesirable human health and environmental effects. Releases into the air may occur and, therefore, the inhalation route is of specific interest. Here we tested copper oxide nanoparticles (CuO NPs) after

  20. Comparative hazard identification of nano- and micro-sized cerium oxide particles based on 28-day inhalation studies in rats

    NARCIS (Netherlands)

    Gosens, Ilse; Mathijssen, Liesbeth E A M; Bokkers, Bas G H|info:eu-repo/dai/nl/304847062; Muijser, Hans; Cassee, Flemming R.|info:eu-repo/dai/nl/143038990

    2014-01-01

    There are many uncertainties regarding the hazard of nanosized particles compared to the bulk material of the parent chemical. Here, the authors assess the comparative hazard of two nanoscale (NM-211 and NM-212) and one microscale (NM-213) cerium oxide materials in 28-day inhalation toxicity studies

  1. Towards an electronic nose based on nano-structured transition metal oxides activated by a tuneable UV light source

    CSIR Research Space (South Africa)

    Mwakikunga, B

    2011-10-01

    Full Text Available Sensors Micromach 2006;126:537?47. [6] F. Hernandez-Ramirez, S. Barth, A. Tarancon, O. Casals, E. Pellicer, J. Rodriguez, ?Water vapor detection with individual tin oxide nanowires,? Nanotechnology 2007;18:424016. [7] D. C. Meier, S. Semancik, B...

  2. Mechanism of mechanochemical synthesis of complex oxides and the peculiarities of their nano-structurization determining sintering

    Directory of Open Access Journals (Sweden)

    Zyryanov V.V.

    2005-01-01

    Full Text Available A mechanism of superfast mechanosynthesis reaction for oxide systems is proposed on the base of a dynamics study. The threshold effect and linear dependence of the chemical response on the effective temperature of the reaction zone are established. Major factors are determined: molecular mass of reagents, enthalpy and difference of reagents in Mohs’s hardness, which also influence the composition of the primary product. Primary acts are characterized by a superfast roller mechanism of mass transfer with the formation of a transient dynamic state (D*. Secondary acts slowly approximate the composition of the product to the composition of the starting mixture by diffusion mass transfer in a deformation mixing regime with a contribution of a rotation (roller mechanism. The list of structure types for complex oxides derived by mechanosynthesis includes perovskites, fluorites, pyrochlors, sheelites, and some other ones. Powders of crystal products display multilevel structurization. In all studied complex oxides strong disordering of the “anti-glass” type was observed. The mechanism of sintering was studied in BaTiO3 powders of different origin and in metastable complex oxides derived by mechanosynthesis. The major contribution in shrinkage belongs to rearrangements of crystalline particles as a whole. Structure transformations accompany, as a rule, sintering of inhomogeneous powders derived by mechanosynthesis.

  3. The potential of nano-structured silicon oxide type coatings deposited by PACVD for control of aquatic biofouling

    NARCIS (Netherlands)

    Akesso, L.; Pettitt, M.E.; Callow, J.A.; Callow, M.E.; Stallard, J.; Teer, D.; Liu, C.; Wang, S.; Zhao, Q.; D'Souza, F.; Willemsen, P.R.; Donnelly, G.T.; Donik, C.; Kocijan, A.; Jenko, M.; Jones, L.A.; Guinaldo, P.C.

    2009-01-01

    SiOx-like coatings were deposited on glass slides from a hexamethylsiloxane precursor by plasma-assisted CVD (PACVD). Surface energies (23.1-45.7 mJ m-1) were correlated with the degree of surface oxidation and hydrocarbon contents. Tapping mode AFM revealed a range of surface topologies with Ra val

  4. Organ burden and pulmonary toxicity of nano-sized copper (II) oxide particles after short-term inhalation exposure

    NARCIS (Netherlands)

    Gosens, Ilse; Cassee, Flemming R; Zanella, Michela; Manodori, Laura; Brunelli, Andrea; Costa, Anna Luisa; Bokkers, Bas G H; de Jong, Wim H; Brown, David; Hristozov, Danail; Stone, Vicki

    2016-01-01

    INTRODUCTION: Increased use of nanomaterials has raised concerns about the potential for undesirable human health and environmental effects. Releases into the air may occur and, therefore, the inhalation route is of specific interest. Here we tested copper oxide nanoparticles (CuO NPs) after repeate

  5. Adhesion of Escherichia coli to nano-Fe/Al oxides and its effect on the surface chemical properties of Fe/Al oxides.

    Science.gov (United States)

    Liu, Zhao-Dong; Li, Jiu-Yu; Jiang, Jun; Hong, Zhi-Neng; Xu, Ren-Kou

    2013-10-01

    We investigated the adhesion of Escherichia coli to α-Fe2O3 and γ-Al2O3 and the effects of adhesion on the surface properties of the oxides in batch experiments, where we conducted potentiometric titration, zeta potential measurements, and FTIR spectroscopy. The adhesion isotherms fitted a Langmuir equation well. γ-Al2O3 had a higher adhesion capacity than α-Fe2O3 because of the higher positive charge on γ-Al2O3. The adhesion of E. coli to Fe/Al oxides decreased with increasing pH. Adhesion increased with increasing NaCl concentration, reaching its maximum at 0.05M for α-Fe2O3 and at 0.1M for γ-Al2O3, after which it decreased with further increases in NaCl concentration. Therefore, the electrostatic force plays an important role in the adhesion of E. coli to Fe/Al oxides. The zeta potential-pH curves of the binary-system fell between that for bacteria and those for Fe/Al oxides. Thus, overlapping of the diffuse layers of the electric double layers on the negatively-charged E. coli and positively-charged Fe/Al oxides reduced the effective surface charge density of the minerals and bacteria. E. coli adhesion decreased the point of zero salt effect and the isoelectric point of the Fe/Al oxides. The FTIR spectra indicated that non-electrostatic force also contributed to the interaction between E. coli and Fe/Al oxides, in addition to the electrostatic force between them. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Synthesis and Characterization of Iodine laden Graphene Nano Platelets via reduction of Graphene Oxide Using Hydrogen Iodide

    Science.gov (United States)

    Sundararaj, Joe Livingston

    This research thesis proposes a novel method for the synthesis, analysis and characterization of Iodinated X-Ray contrast agents using Graphene Nanoplatelets (GNPs) for Computed Tomographic Imaging. Graphene Oxide was synthesized using the Hummers Method of Oxidation [1] through oxidative treatment of Graphite with Potassium Permanganate (KMnO4). The resulting Graphene Oxide was chemically reduced using varying concentrations of Hydrogen Iodide or Hydroiodic acid (HI), rather than the conventionally used highly toxic Hydrazine Hydrate (N2H4) to strip off the oxygen functionalities. In the process of chemical reduction using Hydrogen Iodide, we hypothesized that this would result in the incorporation of Iodine into the Graphitic structure. Raman Spectroscopy, EDS along with XRD analysis provided evidence for the reduction of GO. Raman spectra for reduced GNPs showed an increase in ID/IG ratio from that of graphene oxide and also a peak at 154cm-1 attributed to I5 -. EDS/EDX spectra for HI reduced GO showed a peak at X-ray energy level 3.94KeV characteristic of Iodine. Further analysis using Ion-Selective Electrode measurements confirmed the presence of about 10% Iodine in the Hydroiodic acid reduced samples. SEM and TEM images showed a brief morphology of the Graphene Nanoplatelets. Finally, to elucidate the possibility of Iodinated GNPs to be developed into potential CT contrast agents in the near or far future, CT Phantoms of Iodine loaded GNPs at a concentration of 40mg/ml in water showed excellent contrast density with water and dilute Hydroiodic acid as controls.

  7. Applications of nano-structured metal oxides for treatment of arsenic in water and for antimicrobial coatings

    Science.gov (United States)

    Sadu, Rakesh Babu

    Dependency of technology has been increasing radically through cellular phones for communication, data storage devices for education, drinking water purifiers for healthiness, antimicrobial-coated textiles for cleanliness, nanomedicines for deadliest diseases, solar cells for natural power, nanorobots for engineering and many more. Nanotechnology develops many unprecedented products and methodologies with its adroitness in this modern scientific world. Syntheses of nanomaterials play a significant role in the development of technology. Solution combustion and hydrothermal syntheses produce many nanomaterials with different structures and pioneering applications. Nanometal oxides, like titania, silver oxide, manganese oxide and iron oxide have their unique applications in engineering, chemistry and biochemistry. Likewise, this study talks about the syntheses and applications of nanomaterials such as magnetic graphene nanoplatelets (M-Gras) decorated with uniformly dispersed NPs, manganese doped titania nanotubes (Mn-TNTs), and silver doped titania nanopartcles (nAg-TNPs) and their polyurethane based polymer nanocomposite coating (nAg-TiO2 /PU). Basically, M-Gras, and Mn-TNTs were applied for the treatment of arsenic contaminated water, and nAg- TiO2/PU applied for antimicrobial coatings on textiles. Adsorption of arsenic over Mn- TNTs, and M-Gras was discussed while considering all the regulations of arsenic contamination in drinking water and oxidation of arsenic over Mn-TNTs also discussed with the possible surface reactions. Silver doped titania and its polyurethane nanocomposite was coated on polyester fabric and examined the coated fabric for bactericidal activity for gram-negative (E. coli) and gram-positive ( S. epidermidis) bacteria. This study elucidates the development of suitable nanomaterials and their applications to treat or rectify the environmental hazards while following the scientific standards and regulations.

  8. Poly (lactide-co-glycolide) nano-encapsulation of chelidonine, an active bioingredient of greater celandine (Chelidonium majus), enhances its ameliorative potential against cadmium induced oxidative stress and hepatic injury in mice.

    Science.gov (United States)

    Paul, Avijit; Das, Jayeeta; Das, Sreemanti; Samadder, Asmita; Khuda-Bukhsh, Anisur Rahman

    2013-11-01

    This study evaluates the possible protective potentials of chelidonine and its poly lactide-co-glycolide (PLGA) encapsulated nano-form against cadmium chloride (CdCl₂) induced oxidative stress and hepatotoxicity in mice, ex vivo and in vivo. Acute exposure to CdCl₂ (1.0 mg/kg b.w; i.p., twice a week for 30 days) generated oxidative stress in mice through accumulation of reactive oxygen species and increased lipid peroxidation, and levels of certain liver marker enzymes (ALT, AST, ALP) with decrease in levels of GSH and certain other antioxidant enzymes (SOD, CAT, GR) in liver. Treatment with nano-chelidonine for 30 days after CdCl₂ intoxication significantly reduced oxidative stress and lipid peroxidation and restored levels of GSH, cholesterol, triglyceride and antioxidant enzymes, showing ameliorative changes in histopathology of liver. Expression pattern of certain inflammatory and apoptotic signal proteins also indicated better hepato-protective abilities of nano-chelidonine, making it a more suitable protective drug than chelidonine against cadmium toxicity in mice. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Size-Dependent Neurotoxicity of Aluminum Oxide Particles: a Comparison Between Nano- and Micrometer Size on the Basis of Mitochondrial Oxidative Damage.

    Science.gov (United States)

    Mirshafa, Atefeh; Nazari, Mehdi; Jahani, Daniel; Shaki, Fatemeh

    2017-08-30

    Aluminum nanoparticles (AlNPs) are among the most abundantly produced nanosized particles in the market. There is limited information about the potential harmful effects of aluminum oxide due to its particle size on human health. Considering the toxic effects of Al on brain as its target tissue, in this study, the toxicity of nanoparticles, microparticles, and ionic forms of Al on rat brain and isolated mitochondria was evaluated. Sixty male Wistar rats were divided into ten groups (six rats each), in which group I was the control, and the other groups were administered different doses of Al nanoparticles, Al microparticles (AlMP), and Al ionic forms (2, 4, and 8 mg/kg, i.p.) for 28 days. After 24 h, the animals were killed, brain tissue was separated, the mitochondrial fraction was isolated, and oxidative stress markers were measured. Also, mitochondrial function was assayed by MTT test. The results showed that all forms of Al particles induced ROS formation, lipid peroxidation, protein oxidation, glutathione depletion, mitochondrial dysfunction, and gait abnormalities in a dose-dependent manner. In addition, Al particles decreased mitochondrial membrane potential. These data indicated that oxidative stress might contribute to the toxicity effects of Al. Comparison of oxidative stress markers between all forms of Al revealed that the toxic effect of AlNP on brain tissue was substantially more than that caused by AlMP and bulk form. This study showed more neurotoxicity of AlNPs compared to other forms on brain oxidative damage that probably is due to more penetration into the brain.

  10. Graphene Oxide-terpyridine Conjugate: A Highly Selective Colorimetric and Sensitive Fluorescence Nano-chemosensor for Fe2+ in Aqueous Media

    Directory of Open Access Journals (Sweden)

    Bagher Eftekhari-Sis

    2016-07-01

    Full Text Available A graphene oxide-terpyridine conjugate (GOTC based colorimetric and fluorescent nano-chemosensor was synthesized. It showed high selectivity and sensitivity for Fe2+ and Fe3+ ions in neutral aqueous solution over other metal ions such as Li+, Na+, Ba2+, Ca2+, Al3+, Cd2+, Co2+, Cu2+, Hg2+, Mn2+, Ni2+, Pb2+, Zn2+, Cr3+ and Ag+. In absorption spectra, upon addition of Fe2+ or Fe3+, the sensor displayed a peak at 568 nm, by changing the color of the solution from light pink for GOTC to light magenta and deep magenta for Fe3+ and Fe2+, respectively. Also, the fluorescence studies revealed that, Fe2+, Fe3+ and Co2+ quench the emission of GOTC at 473 nm, while other metal ions do not quench the fluorescence of GOTC in solution. Colorimetric and fluorescence techniques could be used for detection of Fe2+ ion concentration at least about 6-10 μM in water solution. The sensing on test paper was also investigated for the naked-eye detection of Fe2+.

  11. Coherent Fe-rich nano-scale perovskite oxide phase in epitaxial Sr2FeMoO6 films grown on cubic and scandate substrates

    Science.gov (United States)

    Deniz, Hakan; Preziosi, Daniele; Alexe, Marin; Hesse, Dietrich

    2017-01-01

    We report the growth of high-quality epitaxial Sr2FeMoO6 (SFMO) thin films on various unconventional oxide substrates, such as TbScO3, DyScO3, and Sr2Al0.3Ga0.7TaO6 (SAGT) as well as on the most commonly used one, SrTiO3 (STO), by pulsed laser deposition. The films were found to contain a foreign nano-scale phase coherently embedded inside the SFMO film matrix. Through energy dispersive X-ray spectroscopy and scanning transmission electron microscopy, we identified the foreign phase to be Sr2-xFe1+yMo1-yO6, an off-stoichiometric derivative of the SFMO compound with Fe rich content (y ≈ 0.6) and a fairly identical crystal structure to SFMO. The films on STO and SAGT exhibited very good magnetic properties with high Curie temperature values. All the samples have fairly good conducting behavior albeit the presence of a foreign phase. Despite the relatively large number of items of the foreign phase, there is no significant deterioration in the properties of the SFMO films. We discuss in detail how magneto-transport properties are affected by the foreign phase.

  12. 2D/2D nano-hybrids of γ-MnO₂ on reduced graphene oxide for catalytic ozonation and coupling peroxymonosulfate activation.

    Science.gov (United States)

    Wang, Yuxian; Xie, Yongbing; Sun, Hongqi; Xiao, Jiadong; Cao, Hongbin; Wang, Shaobin

    2016-01-15

    Two-dimensional reduced graphene oxide (2D rGO) was employed as both a shape-directing medium and support to fabricate 2D γ-MnO2/2D rGO nano-hybrids (MnO2/rGO) via a facile hydrothermal route. For the first time, the 2D/2D hybrid materials were used for catalytic ozonation of 4-nitrophenol. The catalytic efficiency of MnO2/rGO was much higher than either MnO2 or rGO only, and rGO was suggested to play the role for promoting electron transfers. Quenching tests using tert-butanol, p-benzoquinone, and sodium azide suggested that the major radicals responsible for 4-nitrophenol degradation and mineralization are O2(-) and (1)O2, but not ·OH. Reusability tests demonstrated a high stability of the materials in catalytic ozonation with minor Mn leaching below 0.5 ppm. Degradation mechanism, reaction kinetics, reusability and a synergistic effect between catalytic ozonation and coupling peroxymonosulfate (PMS) activation were also discussed.

  13. PEGylated lipid bilayer-wrapped nano-graphene oxides for synergistic co-delivery of doxorubicin and rapamycin to prevent drug resistance in cancers

    Science.gov (United States)

    Thapa, Raj Kumar; Byeon, Jeong Hoon; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2017-07-01

    Nano-graphene oxide (nGO) is a carbon allotrope studied for its potential as carrier for chemotherapeutic delivery and its photoablation effects. However, interaction of nGO with blood components and the subsequent toxicities warrant a hybrid system for effective cancer drug delivery. Combination chemotherapy aids in effective cancer treatment and prevention of drug resistance. Therefore, in this study, we attempted to prepare polyethylene glycosylated (PEGylated) lipid bilayer-wrapped nGO co-loaded with doxorubicin (DOX) and rapamycin (RAPA), GOLDR, for the prevention and treatment of resistant cancers. Our results revealed a stable GOLDR formulation with appropriate particle size (∼170 nm), polydispersity (∼0.19) and drug loading. Free drug combination (DOX and RAPA) presented synergistic anticancer effects in MDA-MB-231, MCF-7, and BT474 cells. Treatment with GOLDR formulation maintained this synergism in treated cancer cells, which was further enhanced by the near infrared (NIR) laser irradiation-induced photothermal effects of nGO. Higher chromatin condensation and apoptotic body formation, and enhanced protein expression of apoptosis-related markers (Bax, p53, p21, and c-caspase 3) following GOLDR treatment in the presence of NIR laser treatment clearly suggests its superiority in effective chemo-photothermal therapy of resistant cancers. The hybrid nanosystem that we developed provides a basis for the effective use of GOLDR treatment in the prevention and treatment of resistant cancer types.

  14. Study on ion conductivity and crystallinity of composite polymer electrolytes based on poly(ethylene oxide)/poly(acrylonitrile) containing nano-sized Al2O3 fillers.

    Science.gov (United States)

    Kim, Mingyeong; Lee, Lyungyu; Jung, Yongju; Kim, Seok

    2013-12-01

    In this paper, composite polymer electrolytes were prepared by a blend of poly(ethylene oxide) (PEO) and poly(acrylonitrile) (PAN) as a polymer matrix, ethylene carbonate as a plasticizer, LiClO4 as a salt, and by containing a different content of nano-sized Al2O3. The composite films were prepared by using the solution casting method. The crystallinity and ionic conductivity of the polymer electrolytes was investigated using X-ray diffraction (XRD) and AC impedance method, respectively. The morphology of composite polymer electrolyte film was analyzed by SEM method. From the experimental results, by increasing the Al2O3 content, the crystallinity of PEO was reduced, and the ionic conductivity was increased. In particular, by a doping of 15 wt.% Al2O3 in PEO/PAN polymer blend, the CPEs showed the superior ionic conductivity. However, when Al2O3 content exceeds 15 wt.%, the ionic conductivity was decreased. From the surface morphology, it was concluded that the ionic conductivity was decreased because the CPEs showed a heterogenous morphology due to immiscibility or aggregation of the ceramic filler within the polymer matrix.

  15. Exploring the main function of reduced graphene oxide nano-flakes in a nickel cobalt sulfide counter electrode for dye-sensitized solar cell

    Science.gov (United States)

    Lu, Man-Ning; Lin, Jeng-Yu; Wei, Tzu-Chien

    2016-11-01

    Addition of carbonaceous materials into transition metal sulfide counter electrode (CE) of a dye-sensitized solar cell (DSSC) is a common method to improve the performance of the CE and consequent photovoltaic performance. This improvement is almost without exception attributed to the improvement of overall conductivity after the carbonaceous material addition; however, the root function of these carbonaceous materials in promoting the solar cell efficiency is seldom discussed. In this study, highly crystallized nickel cobalt sulfide (NCS) micro-particles were mixed with a small portion of home-made reduced graphene oxide (rGO) nano-flakes. This NCS/rGO hybrid is subjected to extensive characterizations including X-ray diffraction, Raman spectroscopy, field emission scanning microscopy and electrochemical impedance spectroscopy. It is found that the rGO acts bi-functionally including a co-catalyst in accelerating the tri-iodide reduction for the main NCS catalysts, conductivity promotor to decrease the series resistance of the CE. Proved by electrochemical impedance spectroscopy, it is confirmed that the decrease in series resistance is less insignificant than that in charge transfer resistance, indicating rGO functions more profoundly as a co-catalyst than as a conductivity promotor. Moreover, an argument to highlight the requirement of a CE in a dim-light optimized DSSC is also proposed.

  16. High-Performance Wireless Ammonia Gas Sensors Based on Reduced Graphene Oxide and Nano-Silver Ink Hybrid Material Loaded on a Patch Antenna.

    Science.gov (United States)

    Wu, Bian; Zhang, Xingfei; Huang, Beiju; Zhao, Yutong; Cheng, Chuantong; Chen, Hongda

    2017-09-09

    Reduced graphene oxide (rGO) has been studied as a resistive ammonia gas sensor at room temperature. The sensitive hybrid material composed of rGO and nano-silver ink (Ag-ink) was loaded on a microstrip patch antenna to realize high-performance wireless ammonia sensors. The material was investigated using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Firstly, interdigital electrodes (IDEs) printed on the polyethylene terephthalate (PET) by direct printing were employed to measure the variation of resistance of the sensitive material with the ammonia concentration. The results indicated the response of sensor varied from 4.25% to 14.7% under 15-200 ppm ammonia concentrations. Furthermore, the hybrid material was loaded on a microstrip patch antenna fabricated by a conventional printed circuit board (PCB) process, and a 10 MHz frequency shift of the sensor antenna could be observed for 200 ppm ammonia gas. Finally, the wireless sensing property of the sensor antenna was successfully tested using the same emitted antenna outside the gas chamber with a high gain of 5.48 dBi, and an increased reflection magnitude of the emitted antenna due to the frequency mismatch of the sensor antenna was observed. Therefore, wireless ammonia gas sensors loaded on a patch antenna have significant application prospects in the field of Internet of Things (IoTs).

  17. Chitosan mediated synthesis of core/double shell ternary polyaniline/Chitosan/cobalt oxide nano composite-as high energy storage electrode material in supercapacitors

    Science.gov (United States)

    Vellakkat, Mini; Hundekkal, Devendrappa

    2016-01-01

    Nanostructured ternary composite of polyaniline (PANI), Co3O4 nanoparticles, and Chitosan (CS) has been prepared by an in situ chemical oxidation method, and the nanocomposites (CPAESCO) were used as supercapacitor electrodes. The Co3O4 nanoparticles are uniformly coated with CS and PANI layers in it. Different techniques (Fourier transform infrared spectrophotometry, x-ray diffraction, thermal gravimetric analysis, UV-visible spectroscopy, scanning electron microscopy, transmission electron microscopy and electro chemical analysis-cyclic voltammetry, galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy) were used to analyse the optical, structural, thermal, chemical and supercapacitive aspects of the nanocomposites. Core/double shell ternary composite electrode exhibits significantly increased specific capacitance than PANI/Co3O4 or PANI/CS binary composites in supercapacitors. The ternary nanocomposite with 40% nanoparticle exhibits a highest specific capacitance reaching 687 F g-1, Energy density of (95.42 Wh kg-1 at 1 A g-1) and power density of (1549 W kg-1 at 3 A g-1) and outstanding cycling performance, with, 91% capacitance retained over 5000 cycles. It is found that this unique bio compatible nano composite with synergy is a new multifunctional material which will be useful in the design of supercapacitor electrodes and other energy conversion devices too.

  18. Phase equilibria in the neodymium-cadmium binary system.

    Science.gov (United States)

    Skołyszewska-Kühberger, Barbara; Reichmann, Thomas L; Ipser, Herbert

    2014-09-05

    The equilibrium phase diagram of the neodymium-cadmium system has been established by thermal, metallographic and X-ray analysis based on a study of 70 alloys. The system contains three congruently melting intermetallic compounds, i.e. NdCd (1040 °C), NdCd2 (995 °C), Nd11Cd45 (855 °C), and four incongruently melting compounds NdCd3 (860 °C), Nd13Cd58 (740 °C), NdCd6 (655 °C) and NdCd11 (520 °C). Four eutectic reactions are found in this binary system, i.e. at ∼25 at.% Cd and 770 °C, at 58 at.% Cd and 955 °C, at 79 at.% Cd and 850 °C, and very close to pure Cd at 318 °C, as well as one eutectoid reaction at ∼15 at.% Cd and 500 °C. The solid solubility of Nd in Cd is negligible. Dilatometric curves were recorded for three Nd-Cd compositions up to 4 at.% Cd, to accurately determine phase transitions between the solid solutions of Cd in the low- and high-temperature modification of Nd.

  19. Dielectric and impedance behavior of neodymium substituted strontium hexaferrite

    Science.gov (United States)

    Bhat, Bilal Hamid; Samad, Rubiya; Want, Basharat

    2016-09-01

    In this study, dielectric behavior and complex impedance of neodymium (Nd) substituted strontium hexaferrite system: Sr1- x Nd x Fe12O19 ( x = 0.0, 0.05, 0.1, 0.15, 0. 20), synthesized by citrate precursor technique, have been evaluated as a function of applied frequency and temperature. Variation of dielectric constant and dielectric loss with frequency shows the identical behavior for all the compositions. The value of dielectric constant increases with Nd doping. Relaxation process is observed in the composition x = 0.20, and the peaks in this composition shift toward the higher-frequency region as the temperature increases. The dielectric constants show temperature-independent behavior at low temperature, whereas at higher temperatures it increases for all the frequencies. The AC conductivity follows Jonscher's power law, showing that conduction mechanism is due to polaron hopping. Complex impedance as a function of composition and temperature is used to examine the role of grain and grain boundary in the prepared material. Cole-cole plot shows only one semicircle up to x = 0.15, while as for x = 0.20 two semicircles are observed. The conduction mechanism is explained on the basis of both grain and grain boundary.

  20. Dielectric and impedance behavior of neodymium substituted strontium hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, Bilal Hamid; Samad, Rubiya; Want, Basharat [University of Kashmir, Solid State Research Lab., Department of Physics, Srinagar (India)

    2016-09-15

    In this study, dielectric behavior and complex impedance of neodymium (Nd) substituted strontium hexaferrite system: Sr{sub 1-x}Nd{sub x}Fe{sub 12}O{sub 19} (x = 0.0, 0.05, 0.1, 0.15, 0.20), synthesized by citrate precursor technique, have been evaluated as a function of applied frequency and temperature. Variation of dielectric constant and dielectric loss with frequency shows the identical behavior for all the compositions. The value of dielectric constant increases with Nd doping. Relaxation process is observed in the composition x = 0.20, and the peaks in this composition shift toward the higher-frequency region as the temperature increases. The dielectric constants show temperature-independent behavior at low temperature, whereas at higher temperatures it increases for all the frequencies. The AC conductivity follows Jonscher's power law, showing that conduction mechanism is due to polaron hopping. Complex impedance as a function of composition and temperature is used to examine the role of grain and grain boundary in the prepared material. Cole-cole plot shows only one semicircle up to x = 0.15, while as for x = 0.20 two semicircles are observed. The conduction mechanism is explained on the basis of both grain and grain boundary. (orig.)

  1. Interaction of neodymium nitrate with rubidium and cesium nitrates

    Energy Technology Data Exchange (ETDEWEB)

    Molodkin, A.K.; Odinets, Z.K.; S' ' edina, T.V.; Ivanova, T.N. (Universitet Druzhby Narodov, Moscow (USSR))

    1982-12-01

    The Rb/sub 2/Nd(NO/sub 3/)/sub 5/xH/sub 2/O (1) and Cs/sub 2/Nd(NO/sub 3/)/sub 5/xH/sub 2/O (2) new complexes are prepared. The crystals 1 are isotropic, of cubic crystal system, Ng=1.570+-0.002; 2 - Ng=1.582+-0.002; Csub(Np)=0-9 degrees, of low crystal system (syngony). The bands of coordinated nitrate group, the ..delta nu..=..nu../sub 4/(B/sub 2/)-..nu../sub 1/(A/sub 1/) splitting value is respectively equal to 225 and 230 cm/sup -1/ are present in the infrared absorption spectra of the compounds. The interplane distances and corresponding intensities for the 1, 2 and hexahydrate of neodymium nitrate are determined. Derivatograms of the compounds are recorded, the final products of the thermolysis are correspondingly RbNdO/sub 2/ and Nd/sub 2/O/sub 3/.

  2. Dielectric and impedance spectroscopic studies of neodymium gallate

    Energy Technology Data Exchange (ETDEWEB)

    Sakhya, Anup Pradhan, E-mail: npshakya31@gmail.com [Department of Physics, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009 (India); Dutta, Alo [Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India); Sinha, T.P. [Department of Physics, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009 (India)

    2016-05-01

    The AC electrical properties of a polycrystalline neodymium gallate, NdGaO{sub 3} (NGO), synthesized by the sol–gel method have been investigated by employing impedance spectroscopy in the frequency range from 42 Hz to 5 MHz and in the temperature range from 323 K to 593 K. The X-ray diffraction analysis shows that the compound crystallizes in the orthorhombic phase with Pbnm space group at room temperature. Two relaxation processes with different relaxation times are observed from the impedance as well as modulus spectroscopic measurements, which have been attributed to the grain and the grain boundary effects at different temperatures in NGO. The complex impedance data are analyzed by an electrical equivalent circuit consisting of a resistance and a constant phase element in parallel. It has been observed that the value of the capacitance and the resistance associated with the grain boundary is higher than those associated with the grain. The temperature dependent electrical conductivity shows the negative temperature coefficient of resistance. The frequency dependent conductivity spectra are found to follow the power law.

  3. Dielectric and impedance spectroscopic studies of neodymium gallate

    Science.gov (United States)

    Sakhya, Anup Pradhan; Dutta, Alo; Sinha, T. P.

    2016-05-01

    The AC electrical properties of a polycrystalline neodymium gallate, NdGaO3 (NGO), synthesized by the sol-gel method have been investigated by employing impedance spectroscopy in the frequency range from 42 Hz to 5 MHz and in the temperature range from 323 K to 593 K. The X-ray diffraction analysis shows that the compound crystallizes in the orthorhombic phase with Pbnm space group at room temperature. Two relaxation processes with different relaxation times are observed from the impedance as well as modulus spectroscopic measurements, which have been attributed to the grain and the grain boundary effects at different temperatures in NGO. The complex impedance data are analyzed by an electrical equivalent circuit consisting of a resistance and a constant phase element in parallel. It has been observed that the value of the capacitance and the resistance associated with the grain boundary is higher than those associated with the grain. The temperature dependent electrical conductivity shows the negative temperature coefficient of resistance. The frequency dependent conductivity spectra are found to follow the power law.

  4. Power neodymium-glass amplifier of a repetitively pulsed laser

    Energy Technology Data Exchange (ETDEWEB)

    Vinogradov, Aleksandr V; Gaganov, V E; Garanin, Sergey G; Zhidkov, N V; Krotov, V A; Martynenko, S P; Pozdnyakov, E V; Solomatin, I I [Russian Federal Nuclear Center ' All-Russian Research Institute of Experimental Physics' , Sarov, Nizhnii Novgorod region (Russian Federation)

    2011-11-30

    A neodymium-glass diode-pumped amplifier with a zigzag laser beam propagation through the active medium was elaborated; the amplifier is intended for operation in a repetitively pulsed laser. An amplifier unit with an aperture of 20 Multiplication-Sign 25 mm and a {approx}40-cm long active medium was put to a test. The energy of pump radiation amounts to 140 J at a wavelength of 806 nm for a pump duration of 550 {mu}s. The energy parameters of the amplifier were experimentally determined: the small-signal gain per pass {approx}3.2, the linear gain {approx}0.031 cm{sup -1} with a nonuniformity of its distribution over the aperture within 15%, the stored energy of 0.16 - 0.21 J cm{sup -3}. The wavefront distortions in the zigzag laser-beam propagation through the active element of the amplifier did not exceed 0.4{lambda} ({lambda} = 0.63 {mu}m is the probing radiation wavelength).

  5. Dielectric properties of neodymium-modified PLZT ceramics

    Science.gov (United States)

    Płońska, M.; Adamczyk, M.

    2015-08-01

    Relaxor ferroelectrics or relaxors are a class of disordered single crystals and ceramic materials, of peculiar structure as well as properties. The commonly known examples of such materials are Pb(Mg,Nb)O3 (PMN) ceramics as well as single crystals. The second most extensively studied relaxor ceramics is lanthanum-doped lead zirconate-titanate, described as x/65/35 PLZT when lanthanum content is x = 6-10 at%. Throughout the last few decades, there has been an increasing interest in rare-earth-doped PLZT ceramics, because PLZT can be easily substituted with lanthanide elements for La3+ ions. For this reason, the present studies concern the changes in microstructure and crystal structure as well as in dielectric properties, caused by modification of 8/65/35 PLZT with neodymium dopant. Modification of this material with Nd3+ influences the microstructure, electrooptical and dielectric properties, whereas the changes in crystal structure are slight. It was also observed that the maximum value of dielectric properties decreases and moves to a low temperature. Described changes in physical properties are associated with the significant improvement of relaxor properties, characteristic for pure 8/65/35 PLZT ceramics.

  6. Accidental macular hole following Neodymium:YAG posterior capsulotomy

    Directory of Open Access Journals (Sweden)

    Munteanu Mihnea

    2014-01-01

    Full Text Available Introduction. Posterior capsular opacification (PCO is the commonest complication of cataract surgery, occurring in up to one-third of patients in a period of five years. The treatment of choice is the Neodymium:YAG laser posterior capsulotomy. This treatment can be associated with several complications, some of them severe. A rare complication of this procedure is the accidental induced macular hole. Case Outline. A 54-year-old female patient was referred to our Department because of a severe loss of vision and a central scotoma at the right eye. The patient underwent a Nd:YAG posterior capsulotomy 2 days ago, for a PCO. The fundus examination at presentation revealed a round retinal defect in the macular region, a massive inferior preretinal hemorrhage and a mild vitreous hamorrhage. A 6-months follow-up of the case, including retinography and fluorescein angiography, is presented. Conclusion. Although the Nd:YAG laser capsulotomy is a safe, noninvasive, and effective outpatient procedure to improve vision hindered by PCO, it must be recognized that it carries a low but definite risk of serious complications. Physicians and patients should be aware of these rare but severe complications regarding this otherwise safe procedure. Fortunately, most of the complications related to this procedure are transient and can be managed by proper medication.

  7. Effect of annealing temperature on optical properties of binary zinc tin oxide nano-composite prepared by sol-gel route using simple precursors: structural and optical studies by DRS, FT-IR, XRD, FESEM investigations.

    Science.gov (United States)

    Habibi, Mohammad Hossein; Mardani, Maryam

    2015-02-25

    Binary zinc tin oxide nano-composite was synthesized by a facile sol-gel method using simple precursors from the solutions consisting of zinc acetate, tin(IV) chloride and ethanol. Effect of annealing temperature on optical and structural properties was investigated using X-ray diffraction (XRD), diffuse reflectance spectra (DRS), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). XRD results revealed the existence of the ZnO and SnO2 phases. FESEM results showed that binary zinc tin oxide nano-composites ranges from 56 to 60 nm in diameter at 400°C and 500°C annealing temperatures respectively. The optical band gap was increased from 2.72 eV to 3.11 eV with the increasing of the annealing temperature. FTIR results confirmed the presence of zinc oxide and tin oxide and the broad absorption peaks at 3426 and 1602 cm(-1) can be ascribed to the vibration of absorptive water, and the absorption peaks at 546, 1038 and 1410 cm(-1) are due to the vibration of Zn-O or Sn-O groups in binary zinc tin oxide.

  8. Post annealing effects on the properties of sputtered nano-crystallite indium tin oxide thin films on flexible polyimide substrate

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi Gheidari, A.; Iraj, M.; Kazemzad, M.; Behafarid, F. [Materials and Energy Research Center (MERC), Tehran (Iran); Hadad Dabaghi, H. [Departmet of Chemistry, Islamic Azad University of Karaj, Karaj (Iran); Kalhor, D. [Department of Physics, Damghan University of Basic Sciences (Iran)

    2008-07-01

    Indium tin oxide (ITO) thin films were deposited onto flexible polyimide substrates using RF sputtering system at room temperature. The deposited films were then heat treated at different temperatures in air and vacuum atmospheres. The structural variations and as consequence the electro-optical characteristic variations of the films were systematically investigated as a function of post annealing temperature and atmosphere. The structure of the films was studied by means of XRD and SEM techniques and the electro-optical characteristics were measured by four point probe and spectrophotometer, respectively. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Titania Supported Pt and Pt/Pd Nano-particle Catalysts for the Oxidation of Sulfur Dioxide

    DEFF Research Database (Denmark)

    Koutsopoulos, Sotiris; Johannessen, Tue; Eriksen, Kim Michael

    2006-01-01

    Several types of titania (anatase) were used as supports for pure platinum and Pt–Pd bimetallic alloy catalysts. The preparation methods, normal wet impregnation technique and flame aerosol synthesis, obtained metal loadings of 2% by weight. The prepared catalysts were tested for SO2 oxidation...... activity at atmospheric pressure in the temperature range 250–600 °C. The SO2 to SO3 conversion efficiency of the Pt–Pd alloy was significantly higher than that of the individual metals. The effects of the preparation method and the titania type used on the properties and activity of the resulting catalyst...

  10. Effect of interface atomic structure on the electronic properties of nano-sized metal-oxide interfaces.

    Science.gov (United States)

    Qin, Wei; Hou, Jiechang; Bonnell, Dawn A

    2015-01-14

    We report that the size dependence of electronic properties at nanosized metal-semiconducting oxide interfaces is significantly affected by the interface atomic structure. The properties of interfaces with two orientations are compared over size range of 20-200 nm. The difference in interface atomic structure leads to electronic structure differences that alter electron transfer paths. Specifically, interfaces with a higher concentration of undercoordinated Ti result in enhanced tunneling due to the presence of defect states or locally reduced tunnel barrier widths. This effect is superimposed on the mechanisms of size dependent properties at such small scales.

  11. Quasi-SMILES and nano-QFPR: The predictive model for zeta potentials of metal oxide nanoparticles

    Science.gov (United States)

    Toropov, Andrey A.; Achary, P. Ganga Raju; Toropova, Alla P.

    2016-09-01

    Building up of the predictive quantitative structure-property/activity relationships (QSPRs/QSARs) for nanomaterials usually are impossible owing to the complexity of the molecular architecture of the nanomaterials. Simplified molecular input-line entry system (SMILES) is a tool to represent the molecular architecture of ;traditional; molecules for "traditional" QSPR/QSAR. The quasi-SMILES is a tool to represent features (conditions and circumstances), which accompany the behavior of nanomaterials. Having, the training set and validation set, so-called quantitative feature-property relationships (QFPRs), based on the quasi-SMILES, one can build up model for zeta potentials of metal oxide nanoparticles for situations characterized by different features.

  12. The Fundamental Role of Nano-Scale Oxide Films in the Oxidation of Hydrogen and the Reduction of Oxygen on Noble Metal Electrocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Digby Macdonald

    2005-04-15

    The derivation of successful fuel cell technologies requires the development of more effective, cheaper, and poison-resistant electrocatalysts for both the anode (H{sub 2} oxidation in the presence of small amounts of CO from the reforming of carbonaceous fuels) and the cathode (reduction of oxygen in the presence of carried-over fuel). The proposed work is tightly focused on one specific aspect of electrocatalysis; the fundamental role(s) played by nanoscale (1-2 nm thick) oxide (''passive'') films that form on the electrocatalyst surfaces above substrate-dependent, critical potentials, on charge transfer reactions, particularly at elevated temperatures (25 C < T < 200 C). Once the role(s) of these films is (are) adequately understood, we will then use this information to specify, at the molecular level, optimal properties of the passive layer for the efficient electrocatalysis of the oxygen reduction reaction.

  13. Protective effect of quercetin and/or l-arginine against nano-zinc oxide-induced cardiotoxicity in rats

    Science.gov (United States)

    Faddah, L. M.; Baky, Nayira A. Abdel; Mohamed, Azza M.; Al-Rasheed, Nouf M.; Al-Rasheed, Nawal M.

    2013-04-01

    The aim of this study was to investigate the protective role of quercetin and/or l-arginine against the cardiotoxic potency of zinc oxide nanoparticle (ZnO-NP)-induced cardiac infarction. ZnO-NPs (50 nm) were administered orally at either 600 mg or 1 g/kg body weight for 5 consecutive days. The results revealed that co-administration of quercetin and/or l-arginine (each 200 mg/kg body weight) daily for 3 weeks to rats intoxicated by either of the two doses markedly ameliorated increases in serum markers of cardiac infarction, including troponin T, creatine kinase-MB, and myoglobin, as well as increases in proinflammatory biomarkers, including tumor necrosis factor-α, interleukin-6, and C-reactive protein, compared with intoxicated, untreated rats. Each agent alone or in combination also successfully modulated the alterations in serum vascular endothelial growth factor, cardiac calcium concentration, and oxidative DNA damage as well as the increase in the apoptosis marker caspase 3 of cardiac tissue in response to ZnO-NP toxicity. In conclusion, early treatment with quercetin and l-arginine may protect cardiac tissue from infarction induced by the toxic effects of ZnO-NPs.

  14. Biophysical characterization and activity analysis of nano-magnesium supplemented cellulase obtained from a psychrobacterium following graphene oxide immobilization.

    Science.gov (United States)

    Dutta, N; Biswas, S; Saha, M K

    2016-12-01

    Cellulase enzyme was purified from a psychrophilic strain of Bacillus subtilis obtained from east Himalayan mountains. The native enzyme showed optimum activity at 15°C and pH 8.0.The Magnesium oxide nanoparticle (MgN) supplemented enzyme when immobilized on graphene oxide nanosupport (GO), via glutaraldehyde as cross linker, showed 2.98 folds increase in enzymatic activity at 8°C and more than 3.5 folds activity increment at 90°C. The MgN-cel on graphene (GO-MgN-cel) showed a decrease in Km by 6.7 folds at 8°C and 34 folds at 90°C. GO-MgN-cel showed 5 fold and 4.7 fold increase in Vmax at 8°C and 90°C respectively than the untreated enzyme.When compared to native enzyme, GO-MgN-cel had t1/2 (half life) and Ed increased by 72.5 fold and 2.48 fold respectively at 90°C; and 41.6 fold and 2.19 fold respectively at 8°C. Enzymatic activity of GO-MgN-cel was retained even after 12 repeated uses and showed storage stability at 4°C for more than 120days. This nanoparticle assisted immobilization technique can be utilized in bioprocessing industries which require functioning at these extreme ranges of temperature.

  15. Protective effect of quercetin and/or l-arginine against nano-zinc oxide-induced cardiotoxicity in rats

    Energy Technology Data Exchange (ETDEWEB)

    Faddah, L. M.; Baky, Nayira A. Abdel [King Saud University, Pharmacology Department, Faculty of Pharmacy (Saudi Arabia); Mohamed, Azza M., E-mail: azzamohamed99@yahoo.com [King Abdulaziz University, Biochemistry Department, Faculty of Science for Girls (Saudi Arabia); Al-Rasheed, Nouf M.; Al-Rasheed, Nawal M. [King Saud University, Pharmacology Department, Faculty of Pharmacy (Saudi Arabia)

    2013-04-15

    The aim of this study was to investigate the protective role of quercetin and/or l-arginine against the cardiotoxic potency of zinc oxide nanoparticle (ZnO-NP)-induced cardiac infarction. ZnO-NPs (50 nm) were administered orally at either 600 mg or 1 g/kg body weight for 5 consecutive days. The results revealed that co-administration of quercetin and/or l-arginine (each 200 mg/kg body weight) daily for 3 weeks to rats intoxicated by either of the two doses markedly ameliorated increases in serum markers of cardiac infarction, including troponin T, creatine kinase-MB, and myoglobin, as well as increases in proinflammatory biomarkers, including tumor necrosis factor-{alpha}, interleukin-6, and C-reactive protein, compared with intoxicated, untreated rats. Each agent alone or in combination also successfully modulated the alterations in serum vascular endothelial growth factor, cardiac calcium concentration, and oxidative DNA damage as well as the increase in the apoptosis marker caspase 3 of cardiac tissue in response to ZnO-NP toxicity. In conclusion, early treatment with quercetin and l-arginine may protect cardiac tissue from infarction induced by the toxic effects of ZnO-NPs.

  16. Treatment of refractory nano-filtration reject from a tannery using Pd-catalyzed wet air oxidation.

    Science.gov (United States)

    Tripathi, Pranav K; Rao, Nageswara N; Chauhan, Chetan; Pophali, Girish R; Kashyap, Sanjay M; Lokhande, Satish K; Gan, Lihua

    2013-10-15

    We attempted catalytic wet air oxidation (CWAO) of nanofiltration (NF)-reject using Pd based catalyst viz., Pd/activated charcoal (AC) and PdCl2 with the objective of degradation of refractory organic pollutants. Refractory organic pollutants in NF-reject before and after WAO and CWAO were confirmed by GC-MS analysis. Experiments were conducted to investigate the effects of temperature, catalyst dosage and air partial pressure on the rate of removal of total organic carbon (TOC). The reaction kinetics can be conveniently described by considering two-stage first order kinetics. The use of Pd/AC afforded 85% TOC removal, the corresponding rate constant (k) was 2.90 ± 0.075 × 10(-3)min(-1) (Pd/AC, 100mg/L; T, 473.15K; Pair, 0.69 MPa). On the other hand, 75% TOC was removed with k=2.31 ± 0.075 × 10(-3)min(-1) using Pd(2+) catalyst (Pd(2+), 16.66 mg/L; T, 473.15K; Pair, 0.69 MPa). The observed rate of mineralization under Pd-catalyzed conditions was significantly higher than that of the uncatalyzed oxidation (41%) under the similar experimental conditions. Catalyst stability experiments were performed and TEM, SEM, XRD, Raman and XPS characterization data collected. Despite some morphological transformation of support, Pd catalyst was stable under CWAO conditions.

  17. Sonochemical Synthesis of a New Nano Lead(II Coordination Polymer with 2,5-bis(2-pyridyl-3,4-diaza-2,4- hexadiene ligand: A Precursor to Produce Pure Phase Nano- sized Lead(II Oxide

    Directory of Open Access Journals (Sweden)

    A. Morsali

    2011-04-01

    Full Text Available A new nano-sized lead(II coordination polymer, [Pb(2-bpdh(NO32]n (1; (2-bpdh = 2,5-bis(2-pyridyl-3,4-diaza-2,4-hexadiene}, was synthesized by a sonochemical method. The structure of 1 may be considered coordination polymer of lead(II consist of metallocyclicchains formed by bridging NO3- and 2-bpdh ligands. The thermal stability of compound was studied by thermal gravimetric and differential thermal analyses. The new nano-structure coordination polymer was characterized by scanning electron microscopy, powder X-ray diffraction, elemental analyses and IR spectroscopy. The size of the samples was about 50 nm. Nano-particles of PbO were obtained by thermolysis of compound 1in oleic acid as a surfactant at 180 °C under air atmosphere and the size of this PbO particles were about 50 nm.

  18. A photocatalytic approach in micro arc oxidation of WO{sub 3}-TiO{sub 2} nano porous semiconductors under pulse current

    Energy Technology Data Exchange (ETDEWEB)

    Bayati, M.R., E-mail: mbayati@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907 (United States); School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Golestani-Fard, F. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Center of Excellence for Advanced Materials, Iran University of Science and Technology, P.O. Box 16845-195, Tehran (Iran, Islamic Republic of); Moshfegh, A.Z. [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-89694, Tehran (Iran, Islamic Republic of); Molaei, R. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of)

    2011-08-15

    Graphical abstract: WO3-TiO2 layers were fabricated via microarc oxidation process and effect of the electrical current type on their photocatalytic performance under UV and visible illuminations was investigated. Highlights: {yields} WO3-TiO2 layers were grown by MAO under pulse current for the first time. {yields} Effect of the frequency and duty cycle on properties of the layers was studied. {yields} A correlation between catalytic performance and growth conditions was proposed. - Abstract: Since ultraviolet (UV) irradiation cannot be applied for a long time in practical applications, it is necessary to develop a narrow band gap photocatalyst to decompose environmental pollutants under visible irradiation. In this research, (WO{sub 3}){sub x}-(TiO{sub 2}){sub 1-x} nano-porous layers were fabricated by micro arc oxidation (MAO) and influence of the electrical current type on their physical and chemical properties was investigated. Morphological studies, performed by SEM technique, revealed that pore size and roughness decreased with the frequency and increased with the duty cycle. The pulse-grown layers had a finer structure when compared to those fabricated under direct current. XRD and XPS results showed that the layers consisted of anatase, rutile, and tungsten oxide phases. Applying pulse current resulted in higher anatase relative contents. Band gap energies of the MAO-grown TiO{sub 2} and WO{sub 3}-TiO{sub 2} layers were respectively measured as 3.14 and 2.96 eV. The layers fabricated under pulse current exhibited higher photoactivity under ultraviolet and visible illuminations as compared to the layers grown under direct current. Methylene blue (MB) was used as a model material to examine photocatalytic performance of the layers. Maximum MB-photodegradation reaction rate constants over the pulse-synthesized WO{sub 3}-TiO{sub 2} layers were measured as 0.0269 and 0.0129 min{sup -1} for ultraviolet and visible irradiations. For layers grown under direct

  19. Synthesis, characterization and structural control of nano crystalline molybdenum oxide MoO{sub 3} single phase by low cost technique

    Energy Technology Data Exchange (ETDEWEB)

    Afify, H.H.; Hassan, S.A. [Solid State Department, Physics Division, National Research Centre, 33 El Bohouthst. (fromer El Tahrirst.), Dokki, P.O. 12622, Giza (Egypt); Abouelsayed, A., E-mail: as.abouelsayed@gmail.com [Spectroscopy Department, Physics Division, National Research Centre, 33 El Bohouthst. (fromer El Tahrirst.), Dokki, P.O. 12622, Giza (Egypt); Demian, S.E. [Solid State Department, Physics Division, National Research Centre, 33 El Bohouthst. (fromer El Tahrirst.), Dokki, P.O. 12622, Giza (Egypt); Zayed, H.A. [Physics Department, Faculty of Girls for Art, Sciences and Education, Ain Shams University (Egypt)

    2016-06-15

    Thermodynamically stable α- MoO{sub 3} thin film is prepared without any other phases of the molybdenum oxides. Simple and low coast spray pyrolysis technique is used. Growth conditions are optimized to produce pure α- MoO{sub 3} with controlled crystallite size and surface morphology. Small angle (GAXRD) diffractometer is used to elucidate the structure. Profile shape function (PSF) model is made for the experimental data. WinFit software is going first to fit (PSF) to use the refined profile parameters for determination of crystallite size and internal residual strain. The (GAXRD) patterns prove the existence of α- MoO{sub 3} only with layered structure, indicated by the appearance of only (0k0). The calculated crystallite sizes and the strain are found to range from 10 to 28 nm and 0.28%–0.05% respectively. Ultraviolet and Visible transmission measurements were performed over a wavelength range 190–2500 nm on the MoO{sub 3} thin films synthesized by spray pyrolysis technique at different substrate temperature. The two sub-bands corresponds to the electronic transition between the molybdenum oxidation states Mo{sup 4+}, Mo{sup 5+} and Mo{sup 6+} are observed. Quantitative information on the temperature-induced blue shift of the sub-bands was obtained by fitting the spectra with Lorentz functions. The transition from Mo{sup 5+} to Mo{sup 6+} oxidation states show a blue shift up to Tc = 325 °C. Above Tc, the transition Mo{sup 5+} to Mo{sup 6+} increases more drastically, resulting in an anomaly in the temperature-induced shift at Tc. The anomaly can be attributed to the amorphous-to-crystalline phase transition at 325 °C. In addition, both refractive index and extinction coefficient are calculated as a function of substrate temperature. - Highlights: • Single phase α-MoO{sub 3} nano crystalline MoO{sub 3} thin films have been synthesized. • Amorphous-to-crystalline phase transition occurs at 325 °C for MoO{sub 3} thin films. • A clear

  20. Determination of neodymium in rare earth mixtures by fourth-derivative spectrophotometry

    Energy Technology Data Exchange (ETDEWEB)

    Naixing Wang; Weian Liang (Shandong Univ., Jinan, SD (China)); Ping Qi (Shandong Analysis and Test Center, Jinan (China))

    1991-11-20

    The absorption spectra corresponding to 4f electron transitions of the neodymium complex with xylenol orange and cetylpyridinium chloride in the presence of Triton X-100 are reported. The absorption by neo-dymium is increased by factor 666, compared with that of its chloride. Fourth-derivative spectra are used to increase the sensitivity and to eliminate interferences from other rare elements. Beer's law is obeyed for 1.4-7.2 {mu}g Nd in 25 ml of solution. Relative standard deviation is 0.8% for 5.0 {mu}g/25 ml (n=7). Detection limits are 5.0 ng ml{sup -1} for Nd alone and 11.0 ng ml{sup -1} in the presence of 45 ng of lanthanum. Satisfactory results were obtained for the determination of neodymium in rare earth mixtures. (author). 11 refs.; 4 figs.

  1. Uranium and neodymium partitioning in alkali chloride melts using low-melting gallium-based alloys

    Directory of Open Access Journals (Sweden)

    Melchakov Stanislav Yu.

    2015-12-01

    Full Text Available Partitioning of uranium and neodymium was studied in a ‘molten chloride salt - liquid Ga-X (X = In or Sn alloy’ system. Chloride melts were based on the low-melting ternary LiCl-KCl-CsCl eutectic. Nd/U separation factors were calculated from the thermodynamic data as well as determined experimentally. Separation of uranium and neodymium was studied using reductive extraction with neodymium acting as a reducing agent. Efficient partitioning of lanthanides (Nd and actinides (U, simulating fission products and fissile materials in irradiated nuclear fuels, was achieved in a single stage process. The experimentally observed Nd/U separation factor valued up to 106, depending on the conditions.

  2. Investigation of Metal Oxide/Carbon Nano Material as Anode for High Capacity Lithium-ion Cells

    Science.gov (United States)

    Wu, James Jianjun; Hong, Haiping

    2014-01-01

    NASA is developing high specific energy and high specific capacity lithium-ion battery (LIB) technology for future NASA missions. Current state-of-art LIBs have issues in terms of safety and thermal stability, and are reaching limits in specific energy capability based on the electrochemical materials selected. For example, the graphite anode has a limited capability to store Li since the theoretical capacity of graphite is 372 mAh/g. To achieve higher specific capacity and energy density, and to improve safety for current LIBs, alternative advanced anode, cathode, and electrolyte materials are pursued under the NASA Advanced Space Power System Project. In this study, the nanostructed metal oxide, such as Fe2O3 on carbon nanotubes (CNT) composite as an LIB anode has been investigated.

  3. Oxidative Stress and Nano-Toxicity Induced by TiO2 and ZnO on WAG Cell Line.

    Directory of Open Access Journals (Sweden)

    Akhilesh Dubey

    Full Text Available Metallic nanoparticles are widely used in cosmetics, food products and textile industry. These particles are known to cause respiratory toxicity and epithelial inflammation. They are eventually released to aquatic environment necessitating toxicity studies in cells from respiratory organs of aquatic organisms. Hence, we have developed and characterized a new cell line, WAG, from gill tissue of Wallago attu for toxicity assessment of TiO2 and ZnO nanoparticles. The efficacy of the cell line as an in vitro system for nanoparticles toxicity studies was established using electron microscopy, cytotoxicity assays, genotoxicity assays and oxidative stress biomarkers. Results obtained with MTT assay, neutral red uptake assay and lactate dehydrogenase assay showed acute toxicity to WAG cells with IC50 values of 25.29 ± 0.12, 34.99 ± 0.09 and 35.06 ± 0.09 mg/l for TiO2 and 5.716 ± 0.1, 3.160 ± 0.1 and 5.57 ± 0.12 mg/l for ZnO treatment respectively. The physicochemical properties and size distribution of nanoparticles were characterized using electron microscopy with integrated energy dispersive X-ray spectroscopy and Zetasizer. Dose dependent increase in DNA damage, lipid peroxidation and protein carbonylation along with a significant decrease in activity of Superoxide Dismutase, Catalase, total Glutathione levels and total antioxidant capacity with increasing concentration of exposed nanoparticles indicated that the cells were under oxidative stress. The study established WAG cell line as an in vitro system to study toxicity mechanisms of nanoparticles on aquatic organisms.

  4. CO oxidation activity of Cu-CeO2 nano-composite catalysts prepared by laser vaporization and controlled condensation

    Science.gov (United States)

    Sundar, Rangaraj S.; Deevi, Sarojini

    2006-08-01

    Ceria supported copper catalysts were synthesized by laser vaporization and controlled condensation method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX) and temperature programmed reduction (TPR). The catalytic activity of the nanopowders for CO oxidation reaction was tested in a fixed bed flow tube reactor in Ar-20%O2-4%CO mixture. Irrespective of the copper content, the catalytic activity of the nanopowders is similar in the initial CO test, and the catalytic activity improves (i.e. the light-off temperature decreases) during a subsequent run. The lowest light-off temperature during the second run is recorded in the material with 20% copper. TEM studies on 20%Cu-CeO2 sample in the as-prepared condition and after CO test exhibit two types of ceria particles namely, polygonal particles 3-5 nm in size and spherical particles of 15-20 nm in size. Rapid cooling of the nanoparticles formed during the laser ablation results in incorporation of a large amount of copper within the ceria as solid solution. Presence of solid solution of copper is confirmed by EDAX and electron diffraction analyses. In addition, copper-rich surface layer of Cu2O is found over the spherical particles. The cerium oxide components are essentially identical before and after CO test, except that the polygonal CeO2 particles contain newly formed fine crystals of CuO. TPR results reveal two reduction peaks, which further supports, the presence of two different copper species in the material. The shift in light-off temperature during the second run is attributed to the synergistic interaction between newly formed CuO crystals with the CeO2 matrix.

  5. 晶粒度对纳米铜粉抗氧能力的影响%Effect of the Grain Size on the Anti-Oxidizing Ability of Copper Nano-Powders

    Institute of Scientific and Technical Information of China (English)

    李在元; 翟玉春

    2008-01-01

    Taken KBH4 and vitamin C (VC) as reducers, CuSO4· 5H2O as a raw material, EDTA as a complex agent and polyvinyl-pyrolidone (PVP) as a protector, the copper nano-powders were prepared by the liquid reduction method. Placed the powders with different grain sizes in air for an hour, the powders were then examined by XRD, DTA-TG and TEM. The results reveal that the anti-oxidizing ability of the copper nano-powders depends on their grain sizes. When the grain size of the copper nano-powder is bigger, the anti-oxidizing ability is better. If the granularity of the powder is bigger than 75 nm, the powder will not be easily oxidized in air.The 75 nm copper nano-powder samples begin to be oxidized at 120 ℃. The melting point of the copper nano-powder is very low, so the grain will melt and grow up quickly under the TEM elec-tron beam.%以KBH4和维生素C(VC)为还原荆,以CuSO4·5H2O为原料,以EDTA为络合荆,PVP为分散剂,用液相还原法制备不同晶粒度的纳米铜粉.不同晶粒度的纳米铜粉同时在空气中放置1 h后,进行XRD、DTA-TG以及TEM检测.结果表明:不同粒度的纳米铜粉在空气中抗氧化能力不同,晶粒度越大抗氧化能力越强.晶粒度大于75 nm时在空气中放置1 h不被氧化,平均晶粒度为75 nm的纳米铜粉在120℃时开始氧化.纳米铜粉的熔点很低,进行TEM检测时,在电子束照射下颗粒熔融长大.

  6. Hybrid Neodymium-doped passively Q-switched waveguide laser

    Energy Technology Data Exchange (ETDEWEB)

    Salas-Montiel, Rafael [IMEP-LAHC, 3 Parvis Louis Neel BP 257, 38016 Grenoble Cedex 1 (France); Bastard, Lionel [IMEP-LAHC, 3 Parvis Louis Neel BP 257, 38016 Grenoble Cedex 1 (France)], E-mail: lionel.bastard@minatec.inpg.fr; Grosa, Gregory; Broquin, Jean-Emmanuel [IMEP-LAHC, 3 Parvis Louis Neel BP 257, 38016 Grenoble Cedex 1 (France)

    2008-03-25

    In the mid 80s, the doping of optical fibers' core with rare earth atoms has been a major breakthrough in the field of optical telecommunications since it allowed the realization of in line optical amplifiers. However, erbium-doped fiber amplifiers are a few meters long and a huge effort has been made in order to realize compact and efficient active devices based on rare-earth-doped waveguides. For this purpose the use of phosphate glasses instead of silicate ones has been investigated because they allow a better solubility of the inserted rare earths. In this paper we present the realization of a hybrid Neodymium-doped passively Q-switched waveguide laser made by an ion-exchange on a Schott IOG-1 phosphate laser glass combined with the deposition of a bis(4-dimethylaminodithiobenzil)nickel (BDN) saturable absorber diluted in a cellulose acetate polymer cladding. In a first step, we present the continuous wave (CW) operation of the laser with an undoped cladding. We show that for a 3.5 {mu}m wide, 1.5 cm long waveguide realized by a silver-sodium ion-exchange, a 6 mW output has been achieved by creating a Fabry-Perot cavity with dielectric multilayers mirrors sticked to the chip facets. Then, the characterizations performed on the BDN-doped layers are presented. It is shown that a proper selection of the hybrid guiding condition and saturable absorber concentration entail a non-saturated excess absorption of 3.4 dB/cm. Finally, we present the results we obtained on the Q-switched behaviour of the laser. Indeed a repetition rate of 330 kHz is achieved for a pulse energy of 10 nJ and a peak power of 1 W.

  7. Recent Progress in the Development of Neodymium Doped Ceramic Yttria

    Science.gov (United States)

    Prasad, Narasimha S.; Edwards, Chris; Trivedi, Sudhir B.; Kutcher, Susan; Wang, Chen-Chia; Kim, Joo-Soo; Hommerich, Uwe; Shukla, Vijay; Sadangi, Rajendra; Kear, Bernard

    2007-01-01

    Solid-state lasers play a significant role in providing the technology necessary for active remote sensing of the atmosphere. Neodymium doped yttria (Nd:Y2O3) is considered to be an attractive material due to its possible lasing wavelengths of aprrox.914 nm and approx.946 nm for ozone profiling. These wavelengths when frequency tripled can generate UV light at approx.305 nm and approx.315 nm, which is particularly useful for ozone sensing using differential absorption lidar technique. For practical realization of space based UV transmitter technology, ceramic Nd:Y2O3 material is considered to possess great potential. A plasma melting and quenching method has been developed to produce Nd3+ doped powders for consolidation into Nd:Y2O3 ceramic laser materials. This far-from-equilibrium processing methodology allows higher levels of rare earth doping than can be achieved by equilibrium methods. The method comprises of two main steps: (a) plasma melting and quenching to generate dense, and homogeneous doped metastable powders, (b) pressure assisted consolidation of these powders by hot isostatic pressing to make dense nanocomposite ceramics. Using this process, several 1" x 1" ceramic cylinders have been produced. The infrared transmission of undoped Y2O3 ceramics was as high as approx.75% without anti-reflection coating. In the case of Nd:Y2O3 ceramics infrared transmission values of approx.50% were achieved. Furthermore, Nd:Y2O3 samples with dopant concentrations of up to approx.2 at. % were prepared without significant emission quenching.

  8. Samarium-neodymium systematics in kimberlites and in the minerals of garnet lherzolite inclusions

    Science.gov (United States)

    Basu, A.R.; Tatsumoto, M.

    1979-01-01

    The initial ratios of neodymium-143 to neodymium-144 in kimberlites ranging in age between 90 ?? 106 to 1300 ?? 106 years from South Africa, India, and the United States are different from the corresponding ratios in the minerals of peridotite inclusions in the kimberlites but are identical to the ratios in the basaltic achondrite Juvinas at the times of emplacement of the respective kimberlite pipes. This correlation between the kimberlites and Juvinas, which represents the bulk chondritic earth in rare-earth elements, strongly indicates that the kimberlite's source in the mantle is chondritic in rare-earth elements and relatively primeval in composition. Copyright ?? 1979 AAAS.

  9. MICROSTRUCTURE AND WEAR PROPERTIES OF ZIRCONIUM NANO METAL MATRIX COMPOSITES

    OpenAIRE

    Rishav Kumar*, RamachandraNaik AL, Sameer Ahamed, Nitish Kumar Chaubey, Prof.Girish K.B

    2016-01-01

    A356.1 Aluminium alloy reinforced with Nano-sized ZrO2 particle are widely used for high performance applications such as automotive, military, aerospace, and electric  industries because of their improved physical and mechanical properties. In this research, Zirconium Oxide (ZrO2) Nano particle were synthesized by Solution Combustion Synthesis process. Prepared Nano particles were characterized by Powder X-ray diffraction (PXRD). Nano sized Zirconium Particle were reinforced with A356.1...

  10. In Vitro and in Vivo Oxidative Stress and Cytotoxicity Induced by Nano-silica%纳米二氧化硅体内与体外氧化应激及细胞毒性实验研究

    Institute of Scientific and Technical Information of China (English)

    史宏博; 王尊; 于宏升; 刘魁; 岳霞; 郑茹茹; 邹宝波; 赵进顺

    2013-01-01

    To elucidate the mechanisms of nano-silica induced cytotoxicity and oxidative stress in vivo and in vitro. ICR mice were contaminated using nano-silica three times by oral gavage. The level of MDA (malondialdehyde) and SOD (superoxide dismutase) in the lung tissue were detected as in vivo toxicity endpoints for nano-silica induced oxidative stress. In vitro, mouse epithelial cells (JB6 cells) were cultured, and observed for morphologic changes after treatment with different concentrations of nano-silica. Induction of apoptosis by nano-silica via the FAS signaling pathway was examined by western-blot assay. The result shows that nano-silica induced oxidative stress in mice after oral exposure which is indicated by a significant increase of MDA in lung tissue in a dose-response manner. The SOD levels in lung tissue were decreased. Nano-silica caused oxidative damage in JB6 cells exposed to certain dose ranges. Cell apoptosis were also observed in cells stained with YO-PRO-1 dye. Western blot shows a significant increase in the expression of FAS signaling protein induced by nano-silica. However the level of FADD expression was decreased.%  研究了纳米二氧化硅(SiO2)体内及体外氧化应激损伤及细胞毒性作用及机制。体内实验采用ICR小鼠,纳米SiO2经口灌胃染毒3次,检测肺组织中MDA(丙二醛)和SOD(超氧化物歧化酶)含量,观察纳米 SiO2对小鼠肺的氧化应激毒性。采用体外培养的小鼠上皮细胞(JB6细胞),观察不同质量浓度纳米SiO2染毒后的细胞形态改变,通过蛋白免疫印迹实验检测纳米SiO2是否通过FAS 信号途径引起细胞凋亡。研究结果表明:纳米 SiO2经口染毒后对小鼠肺具有氧化应激损伤作用,表现为随染毒剂量的升高,肺组织中 MDA 产生量增加,呈一定的剂量-反应关系。同时,肺组织内 SOD 水平总体趋势降低,但是差别未见统计学意义。体外培养细胞实验中,纳米 SiO2染毒后

  11. A comparison between HfO2/Al2O3 nano-laminates and ternary HfxAlyO compound as the dielectric material in InGaAs based metal-oxide-semiconductor (MOS) capacitors

    Science.gov (United States)

    Krylov, Igor; Pokroy, Boaz; Eizenberg, Moshe; Ritter, Dan

    2016-09-01

    We compare the electrical properties of HfO2/Al2O3 nano-laminates with those of the ternary HfxAlyO compound in metal oxide semiconductor (MOS) capacitors. The dielectrics were deposited by atomic layer deposition on InGaAs. Water, ozone, and oxygen plasma were tested as oxygen precursors, and best results were obtained using water. The total dielectric thickness was kept constant in our experiments. It was found that the effective dielectric constant increased and the leakage current decreased with the number of periods. Best results were obtained for the ternary compound. The effect of the sublayer thicknesses on the electrical properties of the interface was carefully investigated, as well as the role of post-metallization annealing. Possible explanations for the observed trends are provided. We conclude that the ternary HfxAlyO compound is more favorable than the nano-laminates approach for InGaAs based MOS transistor applications.

  12. Organization of research team for nano-associated safety assessment in effort to study nanotoxicology of zinc oxide and silica nanoparticles

    Directory of Open Access Journals (Sweden)

    Kim YR

    2014-12-01

    Full Text Available Yu-Ri Kim,1,* Sung Ha Park,2,* Jong-Kwon Lee,3 Jayoung Jeong,3 Ja Hei Kim,4 Eun-Ho Meang,5 Tae Hyun Yoon,6 Seok Tae Lim,7 Jae-Min Oh,8 Seong Soo A An,9 Meyoung-Kon Kim1 1Department of Biochemistry and Molecular Biology, Korea University Medical School and College, Seoul, South Korea; 2Department of Biochemistry, University of Bath, Bath, UK; 3Toxicological Research Division, National Institute of Food and Drug Safety Evaluation, Chungchungbuk-do, 4Consumers Korea, Chongro-ku, 5General toxicology team, Korea Testing and Research Institute, 6Laboratory of Nanoscale Characterization and Environmental Chemistry, Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul, 7Department of Nuclear Medicine, Chonbuk National University Medical School, Jeonju, Jellabuk-Do, 8Department of Chemistry and Medical Chemistry, College of Science and Technology, Yonsei University, Gangwon-do, 9Department of Bionanotechnology, Gachon Medical Research Institute, Gachon University, Seongnam, South Korea *Authors contributed equally to this work Abstract: Currently, products made with nanomaterials are used widely, especially in biology, biotechnologies, and medical areas. However, limited investigations on potential toxicities of nanomaterials are available. Hence, diverse and systemic toxicological data with new methods for nanomaterials are needed. In order to investigate the nanotoxicology of nanoparticles (NPs, the Research Team for Nano-Associated Safety Assessment (RT-NASA was organized in three parts and launched. Each part focused on different contents of research directions: investigators in part I were responsible for the efficient management and international cooperation on nano-safety studies; investigators in part II performed the toxicity evaluations on target organs such as assessment of genotoxicity, immunotoxicity, or skin penetration; and investigators in part III evaluated the toxicokinetics of NPs with newly developed

  13. Some new nano-sized Fe(II), Cd(II) and Zn(II) Schiff base complexes as precursor for metal oxides: Sonochemical synthesis, characterization, DNA interaction, in vitro antimicrobial and anticancer activities.

    Science.gov (United States)

    Abdel-Rahman, Laila H; Abu-Dief, Ahmed M; El-Khatib, Rafat M; Abdel-Fatah, Shimaa Mahdy

    2016-12-01

    The complexes of Fe(II), Cd(II) and Zn(II) with Schiff base derived from 2-amino-3-hydroxypyridine and 3-methoxysalicylaldehyde have been prepared. Melting points, decomposition temperatures, Elemental analyses, TGA, conductance measurements, infrared (IR) and UV-Visible spectrophotometric studies were utilized in characterizing the compounds. The UV-Visible spectrophotometric analysis revealed 1:1 (metal-ligand) stoichiometry for the three complexes. In addition to, the prepared complexes have been used as precursors for preparing their corresponding metal oxides nanoparticles via thermal decomposition. The structures of the nano-sized complexes and their metal oxides were characterized by X-ray powder diffraction and transmittance electron microscopy. Moreover, the prepared Schiff base ligand, its complexes and their corresponding nano-sized metal oxides have been screened in vitro for their antibacterial activity against three bacteria, gram-positive (Microccus luteus) and gram-negative (Escherichia coli, Serratia marcescence) and three strains of fungus. The metal chelates were shown to possess more antimicrobial activity than the free Schiff-base chelate and their nano-sized metal oxides have the highest activity. The binding behaviors of the complexes to calf thymus DNA have been investigated by absorption spectra, viscosity mensuration and gel electrophoresis. The DNA binding constants reveal that all these complexes interact with DNA through intercalative binding mode. Furthermore, the cytotoxic activity of the prepared Schiff base complexes on human colon carcinoma cells, (HCT-116 cell line) and hepatic cellular carcinoma cells, (HepG-2) showed potent cytotoxicity effect against growth of carcinoma cells compared to the clinically used Vinblastine standard. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Preparation of Modified Magnetic Nano-Fe3O4 Chitosan/ Graphene Oxide for the Preconcentration and Determination of Copper (П Ions in Biological and Environmental Water Samples Prior to Flame Atomic Absorption Spectrometry.

    Directory of Open Access Journals (Sweden)

    Mohammd Yari

    2016-06-01

    Full Text Available A simple, highly sensitive, accurate and selective method for determination of trace amounts of Cu2+in water samples .In this paper, chitosan grafted with graphene oxide sheets showed an increased surface area was used to encapsulate nano-Fe3O4 and produce a nano-Fe3O4-encapsulated-chitosan/graphene oxide sorbent based new sorbent was prepared. Flame atomic absorption spectrometer was utilized for determination of Cu2+.Some of the important parameters on the preconcentration and complex formation were selected and optimized. Under the optimized conditions the limit of detection (LOD and limit of quantification (LOQwere 0.30,0.750 and the proposed method has a good reproducibility 0.90% (RSD %.The enrichment factor was 200 and the percentage of recovery was in the range of 95-100% .The method was successfully applied to the recovery of Cu2+in different type of water samples. Graphene oxide and its derivates such as magnetic nano-Fe3O4-encapsulated-chitosan/graphene oxide in this study is full of potential to use as an excellent adsorbent in the extraction method like solid phase extraction(SPE and solid phase micro extraction(SPME. In the present study, we report the application of pre concentration techniques still continues increasingly for trace metal determinations by flame atomic absorption spectrometry (FAAS for quantification of Cu2+ in Formalin-fixed paraffin-embedded (FFPE tissues from Liver loggerhead turtles. This method exhibits the superiority in compared to the other adsorption reagents because of the fact that there is no necessity of any complexing reagent and optimum pH of solution presents in acidic media.

  15. Lack of nano size effect on electrochemistry of dopamine at a gold nanoparticle modified indium tin oxide electrode

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Nanometer sized materials have been shown to possess excellent chemical and electrochemical catalytic properties.In this work,a gold nanoparticle (AuNP) modified indium tin oxide (ITO) electrode was employed for investigating its electro-catalytic property.AuNP was deposited on the 3-aminopropyltriethoxysilane (APTES) modified ITO electrode by self-assembly,and was characterized by scanning electron microscopy and cyclic voltammetry.Although the electrochemical reaction of dopamine was very sluggish on the ITO/APTES electrode,it was significantly enhanced after AuNP deposition.The cyclic voltammogram exhibited apparent dependence on the surface coverage of 11 nm AuNPs,which could be rationalized by different modes of mass diffusion.Among the different sizes of AuNP investigated,the lowest anodic peak potential was observed on 11 nm AuNP.However,the potential was still about 50 mV more positive than that obtained on a bulk gold electrode of similar geometry.It is therefore concluded that there is no nanometer size effect of AuNP modified ITO on the electrochemistry of dopamine.

  16. Impedance spectroscopy of highly ordered nano-porous electrodes based on Au-AAO (anodic aluminum oxide) structure.

    Science.gov (United States)

    Ahn, Jaehwan; Cho, Sungbo; Min, Junhong

    2013-11-01

    Electrochemical measurements using the microelectrodes are increasingly utilized for the label-free detection of the small amount of biological materials such as DNA, protein, and cells. However, the interfacial electrode impedance increases and may hinder the detection of weak signals as the size of electrode decreases. To enhance the measurement sensitivity while reducing the electrode size, in this study, microelectrodes employing a nanoporous structure were fabricated and characterized by using electrical impedance spectroscopy. We made the highly ordered honeycomb nanoporous structure of Anodic Aluminum Oxide (AAO) by electrochemical anodizing and formed Au layer on the surface of AAO (Au/AAO) by electroless Au plating method. The electrical characteristics of the fabricated Au/AAO electrodes were evaluated by using de Levie's model derived for the pore electrodes. As a result, the interfacial electrode impedance of the fabricated Au/AAO electrodes was 2-3 order lower than the value of the planar electrodes at frequencies below 1 kHz. It implies this nanoporous electrode could be directly applied to label free detection of biomaterials.

  17. Porous nano-cerium oxide wood chip biochar composites for aqueous levofloxacin removal and sorption mechanism insights.

    Science.gov (United States)

    Yi, Shengze; Sun, Yuanyuan; Hu, Xin; Xu, Hongxia; Gao, Bin; Wu, Jichun

    2017-01-14

    The adsorption removal of levofloxacin (LEV), a widely used fluoroquinolone antibiotic, by using the biochars derived from the pyrolysis of pine wood chip pretreated with cerium trichloride was investigated through batch sorption experiments and multiple characterization techniques. The differences in the basic physicochemical properties between Ce-impregnated biochars and the pristine biochars were confirmed by the analysis of elemental compositions, specific surface areas, energy dispersive spectrometry, X-ray diffraction, and thermo-gravimetry. FT-IR spectra of the pre- and post-sorption biochars confirmed the chemical adsorption for LEV sorption onto the biochars. Large shifts in the binding energy of Ce3d, O1s, C1s, and N1s regions on the pre- and post-sorption biochars indicated the surface complexation of LEV molecule onto the biochars. The binding species of Ce(4+) and Ce(3+) identified by X-ray photoelectron spectroscopy reflect the role of Ce oxides during sorption. Batch adsorption showed the significant enhancement of adsorption capacity for LEV after the Ce modification. Batch adsorption kinetic data fitted well with the pseudo-second-order model. Both the Langmuir and the Freundlich models reproduced the isotherm data well. Findings from this work indicated that Ce-impregnated biochars can be effective for the removal of aqueous LEV.

  18. Magnetic nano graphene oxide as solid phase extraction adsorbent coupled with liquid chromatography to determine pseudoephedrine in urine samples.

    Science.gov (United States)

    Taghvimi, Arezou; Hamishehkar, Hamed; Ebrahimi, Mahmoud

    2016-01-15

    This paper reports on a method based on magnetic solid phase extraction (MSPE) for the determination of pseudoephedrine. Magnetic nanographene oxide (MNGO) was applied as a new adsorbent for the extraction of pseudoephedrine from urine samples. Synthesis of MNGO was characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The main factors influencing extraction efficiency, including the amounts of sample volume, amount of adsorbent, type and amount of extraction organic solvent, time of extraction and desorption, pH, ionic strength of extraction medium, and agitation rate, were investigated and optimized. Under optimized extraction conditions, a good linearity was observed in the range of 100-2000ng/mL with a correlation coefficient of 0.9908 (r(2)). Limit of detection (LOD) and limit of quantification (LOQ) were 25 and 82.7ng/mL, respectively. Inter-day and intra-day precision and accuracy were 6.01 and 0.34 (%), and 8.70 and 0.29 (%), respectively. The method was applied for the determination of pseudoephedrine in urine samples of volunteers receiving pseudoephedrine with the recovery of 96.42. It was concluded that the proposed method can be applied in diagnostic clinics.

  19. Technical Note: A Simulation Study on the Feasibility of Radiotherapy Dose Enhancement with Calcium Tungstate and Hafnium Oxide Nano- and Microparticles.

    Science.gov (United States)

    Sherck, Nicholas J; Won, You-Yeon

    2017-09-18

    To assess the radiotherapy dose enhancement (RDE) potential of calcium tungstate (CaWO4 ) and hafnium oxide (HfO2 ) nano- and microparticles (NPs). A Monte Carlo simulation study was conducted to gauge their respective RDE potentials relative to that of the broadly studied gold (Au) NP. The study was warranted due to the promising clinical and preclinical studies involving both CaWO4 and HfO2 NPs as RDE agents in the treatment of various types of cancers. The study provides a baseline RDE to which future experimental RDE trends can be compared to. All three materials were investigated in silico with the software Penetration and Energy Loss of Positrons and Electrons (PENELOPE 2014) developed by Francesc Salvat and distributed in the United States by the Radiation Safety Information Computational Center (RSICC) at Oak Ridge National Laboratory. The work utilizes the extensively studied Au NP as the "gold standard" for a baseline. The key metric used in the evaluation of the materials was the local dose enhancement factor (DEFloc ). An additional metric used, termed the relative enhancement ratio (RER), evaluates material performance at the same mass concentrations. The results of the study indicate that Au has the strongest RDE potential using the DEFloc metric. HfO2 and CaWO4 both underperformed relative to Au with lower DEFloc of 2-3× and 4-100×, respectively. The computational investigation predicts the RDE performance ranking to be: Au > HfO2 > CaWO4 . This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. Thermoelectric properties of nano-granular indium-tin-oxide within modified electron filtering model with chemisorption-type potential barriers

    Science.gov (United States)

    Brinzari, V.; Nika, D. L.; Damaskin, I.; Cho, B. K.; Korotcenkov, G.

    2016-07-01

    In this work, an approach to the numerical study of the thermoelectric parameters of nanoscale indium tin oxide (ITO, Sn content<10 at%) based on an electron filtering model (EFM) was developed. Potential barriers at grain boundaries were assumed to be responsible for a filtering effect. In the case of the dominant inelastic scattering of electrons, the maximal distance between potential barriers was limited in this modified model. The algorithm for such characteristic length calculation was proposed, and its value was evaluated for ITO. In addition, the contributions of different scattering mechanisms (SMs) in electron transport were examined. It was confirmed that in bulk ITO, the scattering on polar optical phonons (POPs) and ionized impurities dominates, limiting electron transport. In the framework of the filtering model, the basic thermoelectric parameters (i.e., electrical conductivity, mobility, Seebeck coefficient, and power factor (PF)) were calculated for ITO in the temperature range of 100-500 °C as a function of potential barrier height. The results demonstrated a sufficient rise of the Seebeck coefficient with an increase in barrier height and specific behavior of PF. It was found that PF is very sensitive to barrier height, and at its optimal value for granular ITO, it may exceed the PF for bulk ITO by 3-5 times. The PF maximum was achieved by band bending, slightly exceeding Fermi energy. The nature of surface potential barriers in nano-granular ITO with specific grains is due to the oxygen chemisorption effect, and this can be observed despite of the degeneracy of the conduction band (CB). This hypothesis and the corresponding calculations are in good agreement with recent experimental studies [Brinzari et al. Thin Solid Films 552 (2014) 225].

  1. Nano-assemblies consisting of Pd/Pt nanodendrites and poly (diallyldimethylammonium chloride)-coated reduced graphene oxide on glassy carbon electrode for hydrogen peroxide sensors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanyan; Zhang, Cong; Zhang, Di; Ma, Min; Wang, Weizhen; Chen, Qiang, E-mail: qiangchen@nankai.edu.cn

    2016-01-01

    Non-enzymatic hydrogen peroxide (H{sub 2}O{sub 2}) sensors were fabricated on the basis of glassy carbon (GC) electrode modified with palladium (Pd) core-platinum (Pt) nanodendrites (Pt-NDs) and poly (diallyldimethylammonium chloride) (PDDA)-coated reduced graphene oxide (rGO). A facile wet-chemical method was developed for preparing Pd core-Pt nanodendrites. In this approach, the growth of Pt NDs was directed by Pd nanocrystal which could be regarded as seed. The PDDA-coated rGO could form uniform film on the surface of GC electrode, which provided a support for Pd core- Pt NDs adsorption by self-assembly. The morphologies of the nanocomposites were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction (spectrum). Electrocatalytic ability of the nanocomposites was evaluated by cyclic voltammetry and chronoamperometric methods. The sensor fabricated by Pd core-Pt NDs/PDDA-rGO/GCE exhibited high sensitivity (672.753 μA mM{sup −1} cm{sup −2}), low detection limit (0.027 μM), wider linear range (0.005–0.5 mM) and rapid response time (within 5 s). Besides, it also exhibited superior reproducibility, excellent anti-interference performance and long-term stability. The present work could afford a viable method and efficient platform for fabricating all kinds of amperometric sensors and biosensors. - Highlights: • A facial wet-chemical method was developed for preparing Pd core-Pt nanodendrites. • The morphologies of graphene and Pd core-Pt nanodendrites were characterized. • A novel H{sub 2}O{sub 2} sensor was fabricated by nano-assembly. • The performance of H{sub 2}O{sub 2} sensor was evaluated by cyclic voltammetry and chronoamperometric methods.

  2. Enhanced efficiency of polymer solar cells by structure-differentiated silver nano-dopants in solution-processed tungsten oxide layer

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Wenfei [Institute of Hybrid Materials, The Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Tang, Jianguo, E-mail: jianguotangde@hotmail.com [Institute of Hybrid Materials, The Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Wang, Die [Institute of Hybrid Materials, The Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Yang, Renqiang, E-mail: yangrq@qibebt.ac.cn [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China); Chen, Weichao; Bao, Xichang [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China); Wang, Yao; Jiao, Jiqing; Wang, Yanxin; Huang, Zhen; Huang, Linjun; Liu, Jixian; Wang, Wei [Institute of Hybrid Materials, The Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Wu, Pinghui [State Key Laboratory of Modern Optical Instrumentation, Department of Optical Engineering, Zhejiang University, Hangzhou 310027 (China); Belfiore, Laurence A., E-mail: belfiore@engr.colostate.edu [Institute of Hybrid Materials, The Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO 80523 (United States)

    2016-04-15

    Graphical abstract: - Highlights: • Incorporating different structures of Ag NPs in solution-processed WO{sub 3} layer. • The LSPR effect of metallic nanoparticles is represented by FDTD method. • Enhanced PCE are greatly increased by the LSPR effect of SiAgP and nAgPl. • Naked Ag nanoparticles decreased the PCE of PSCs due to the interface excitons quenching. • Avoiding interface excitons quenching is greatly needed for utilizing metallic NPS in PSCs. - Abstract: In this article, we creatively incorporate naked Ag nanoparticles (nAgp), SiO{sub 2}-covered Ag nanoparticles (SiAgp), and naked Ag nanoplates (nAgPl) into solution-processed tungsten oxide (WO{sub 3}) hole transport layer in polymer solar cells (PSCs) to increase the light absorption through localized surface plasmon resonance (LSPR) effect. With optimized doping concentrations, nAgp decreases power conversion efficiency (PCE), however, SiAgp increases PCE by 13.2% and nAgPl increases PCE by 19.7%. In detail, the great PCEs discrepancies are mainly caused by the discrepancies of short circuit currents (J{sub sc}). The experiments results indicate that the naked surface of nAgp causes the exciton-quenching to decrease the J{sub sc} of PSCs. Whereas the capsulation of SiO{sub 2} at the surface of nAgp and the embedment of nAgPl in WO{sub 3} layer can prevent the exciton-quenching and help to use LSPR effect of Ag nano-dopants to enhance the J{sub sc} of PSCs.

  3. Pure magnesium micro-arc oxidation coating containing nano-SiO2 or nano-TiO2 promotes proliferation and viability of osteoblasts%含纳米SiO 2或纳米TiO 2微弧氧化纯镁生物涂层可促进成骨细胞增殖及活性

    Institute of Scientific and Technical Information of China (English)

    刘继光; 王立峰; 李慕勤; 高燕; 王晓伟

    2015-01-01

    BACKGROUND:The micro-arc oxidation technology can enhance the corrosion resistance of magnesium and its aloys to improve the biological properties of the surface. OBJECTIVE: In order to regulate the biological activity of medical pure magnesium, to modify the micro-arc oxidation coating by adding nano-SiO2 and nano-TiO2 into the plating solution, and to study the biological coating effects on osteoblast proliferation and differentiation. METHODS: Round magnesium sheets were divided into three groups, respectively treated with silicate electrolyte containing 7.5 g/L nano-SiO2 (nano-SiO2 group), 4.8 g/L nano-TiO2 (nano-TiO2 group), and nothing (control group). Passage 3 osteoblasts were seeded onto the specimen surface in the three groups to observe the early morphology, proliferation and alkaline phosphatase activity of osteoblasts. RESULTS AND CONCLUSION:Osteoblasts grew wel in the nano-SiO2 group and nano-TiO2 group, presenting with clear outline, and the cels were long spindle- and polygon-shaped. But in the control group, the cels grew poor in the specimen surface. Cel counting kit-8 test showed that the absorbance values and alkaline phosphatase activities were increased with time in the three groups. Compared with the control group, the proliferative activity was higher in the nano-SiO2 group and nano-TiO2 group at days 1, 3, 5 after seeding, while the activity of alkaline phosphatase was also higher in the nano-SiO2 group and nano-TiO2 group at days 3, 5 after seeding. These findings indicate the micro-arc oxidation coatings containing nano-SiO2and nano-TiO2 can promote osteoblast proliferation and osteogenetic activity, which have good biocompatibility.%背景:微弧氧化技术可增强镁及其合金的耐腐蚀性,提高其表面生物性能。  目的:为了调控医用纯镁的生物活性,在镀液中添加纳米 SiO2或纳米 TiO2对纯镁微弧氧化涂层改良,研究其对成骨细胞增殖及分化的影响。  方

  4. Green synthesis of nano zinc oxide and evaluation of its impact on germination and metabolic activity of Solanum lycopersicum.

    Science.gov (United States)

    Singh, Ajey; Singh, N B; Hussain, Imtiyaz; Singh, Himani; Yadav, Vijaya; Singh, S C

    2016-09-10

    In the present study, zinc oxide nanoparticles (ZnO NPs) were rapidly synthesized at room temperature by treating zinc acetate dihydrate with the flower extract of Elaeagnus angustifolia (Russian olive). The formation of ZnO NPs was primarily confirmed by UV-visible absorption spectrum in the range of 250-700nm. XRD analysis and DLS particle size analyzer revealed the size of ZnO NPs. The FTIR spectrum revealed the presence of phytochemicals in the flower extract mediated ZnO NPs. Moreover, the morphology of the ZnO NPs was determined using SEM. Seeds of Solanum lycopersicum (tomato) were separately treated with different concentrations of synthesized ZnO NPs and zinc sulphate (ZnSO4) salt suspensions (common zinc supplement). The effect of these treatments on seed germination, seedling vigor, chlorophyll, protein and sugar contents as well as on the activities of lipid peroxidation and antioxidant enzyme were studied. Leaves of plants treated with 6.1mM concentration of ZnO NPs recorded maximum reflectance while it was minimum in plants treated with 1.2mM concentration of NPs. The effect of synthesized ZnO NPs on seedling vigor, pigment, protein and sugar content was found affirmative at lower concentrations contrary to control and ZnSO4 salt. The inhibitory effect at higher concentration of NPs indicated importance in the precise application of NPs, in Zn deficient system, where plant response varies with concentration. To the best of our knowledge this is the first report on Elaeagnus angustifolia mediated synthesis of ZnO NPs and their effects on germination and physiological activity of tomato.

  5. Enhanced dielectric properties of poly(vinylidene fluoride) composites filled with nano iron oxide-deposited barium titanate hybrid particles

    Science.gov (United States)

    Zhang, Changhai; Chi, Qingguo; Dong, Jiufeng; Cui, Yang; Wang, Xuan; Liu, Lizhu; Lei, Qingquan

    2016-09-01