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Sample records for aluminum oxide nanoparticles

  1. Specific features of aluminum nanoparticle water and wet air oxidation

    International Nuclear Information System (INIS)

    The oxidation processes of the electrically exploded aluminum nanopowders in water and in wet air are examined in the paper. The morphology of the intermediate reaction products of aluminum oxidation has been studied using the transmission electron microscopy. It was shown that the aluminum nanopowder water oxidation causes the formation of the hollow spheres with mesoporous boehmite nanosheets coating. The wedge-like bayerite particles are formed during aluminum nanopowder wet air oxidation

  2. Enhanced photocatalytic activity of electrochemically synthesized aluminum oxide nanoparticles

    Science.gov (United States)

    Pathania, Deepak; Katwal, Rishu; Kaur, Harpreet

    2016-03-01

    In this study, aluminum oxide (Al2O3) nanoparticles (NPs) were synthesized via an electrochemical method. The effects of reaction parameters such as supporting electrolytes, solvent, current and electrolysis time on the shape and size of the resulting NPs were investigated. The Al2O3 NPs were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, thermogravimetric analysis/differential thermal analysis, energy-dispersive X-ray analysis, and ultraviolet-visible spectroscopy. Moreover, the Al2O3 NPs were explored for photocatalytic degradation of malachite green (MG) dye under sunlight irradiation via two processes: adsorption followed by photocatalysis; coupled adsorption and photocatalysis. The coupled process exhibited a higher photodegradation efficiency (45%) compared to adsorption followed by photocatalysis (32%). The obtained kinetic data was well fitted using a pseudo-first-order model for MG degradation.

  3. Comparative effects of macro-sized aluminum oxide and aluminum oxide nanoparticles on erythrocyte hemolysis: influence of cell source, temperature, and size

    International Nuclear Information System (INIS)

    Al2O3 is the most abundantly produced nanomaterial and has been used in diverse fields, including the medical, military, and industrial sectors. As there are concerns about the health effects of nanoparticles, it is important to understand how they interact with cells, and specifically with red blood cells. The hemolysis induced by three commercial nano-sized aluminum oxide particles (nanopowder 13 nm, nanopowder <50 nm, and nanowire 2–6 × 200–400 nm) was compared to aluminum oxide and has been studied on erythrocytes from humans, rats, and rabbits, in order to elucidate the mechanism of action and the influence of size and shape on hemolytic behavior. The concentrations inducing 50 % hemolysis (HC50) were calculated for each compound studied. The most hemolytic aluminum oxide particles were of nanopowder 13, followed by nanowire and nanopowder 50. The addition of albumin to PBS induced a protective effect on hemolysis in all the nano-forms of Al2O3, but not on Al2O3. The drop in HC50 correlated to a decrease in nanomaterial size, which was induced by a reduction of aggregation. Aluminum oxide nanoparticles are less hemolytic than other oxide nanoparticles and behave differently depending on the size and shape of the nanoparticles. The hemolytic behavior of aluminum oxide nanoparticles differs from that of aluminum oxide

  4. Comparative effects of macro-sized aluminum oxide and aluminum oxide nanoparticles on erythrocyte hemolysis: influence of cell source, temperature, and size

    Energy Technology Data Exchange (ETDEWEB)

    Vinardell, M. P., E-mail: mpvinardellmh@ub.edu; Sordé, A. [Universitat de Barcelona, Departament de Fisiologia, Facultat de Farmàcia (Spain); Díaz, J. [Universitat de Barcelona CCiT, Scientific and Technological Centers (Spain); Baccarin, T.; Mitjans, M. [Universitat de Barcelona, Departament de Fisiologia, Facultat de Farmàcia (Spain)

    2015-02-15

    Al{sub 2}O{sub 3} is the most abundantly produced nanomaterial and has been used in diverse fields, including the medical, military, and industrial sectors. As there are concerns about the health effects of nanoparticles, it is important to understand how they interact with cells, and specifically with red blood cells. The hemolysis induced by three commercial nano-sized aluminum oxide particles (nanopowder 13 nm, nanopowder <50 nm, and nanowire 2–6 × 200–400 nm) was compared to aluminum oxide and has been studied on erythrocytes from humans, rats, and rabbits, in order to elucidate the mechanism of action and the influence of size and shape on hemolytic behavior. The concentrations inducing 50 % hemolysis (HC{sub 50}) were calculated for each compound studied. The most hemolytic aluminum oxide particles were of nanopowder 13, followed by nanowire and nanopowder 50. The addition of albumin to PBS induced a protective effect on hemolysis in all the nano-forms of Al{sub 2}O{sub 3}, but not on Al{sub 2}O{sub 3}. The drop in HC{sub 50} correlated to a decrease in nanomaterial size, which was induced by a reduction of aggregation. Aluminum oxide nanoparticles are less hemolytic than other oxide nanoparticles and behave differently depending on the size and shape of the nanoparticles. The hemolytic behavior of aluminum oxide nanoparticles differs from that of aluminum oxide.

  5. Stabilization of aluminum doped zinc oxide nanoparticle suspensions and their application in organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, N., E-mail: nadine.wolf@zae-bayern.de [Bavarian Center for Applied Energy Research (ZAE Bayern), Division: Energy Efficiency, Am Galgenberg 87, 97074 Wuerzburg (Germany); Stubhan, T. [Institute of Materials for Electronics and Energy Technology (I-MEET), Friedrich-Alexander-University of Erlangen-Nuremberg, Martensstraße 7, 91058 Erlangen (Germany); Manara, J.; Dyakonov, V. [Bavarian Center for Applied Energy Research (ZAE Bayern), Division: Energy Efficiency, Am Galgenberg 87, 97074 Wuerzburg (Germany); Brabec, C.J. [Institute of Materials for Electronics and Energy Technology (I-MEET), Friedrich-Alexander-University of Erlangen-Nuremberg, Martensstraße 7, 91058 Erlangen (Germany); Bavarian Center for Applied Energy Research (ZAE Bayern), Division: Renewable Energies, Haberstraße 2a, 91058 Erlangen (Germany)

    2014-08-01

    Aluminum doped zinc oxide (AZO) nanoparticles were redispersed in isopropyl alcohol and stabilized with different stabilizers and mixtures of stabilizers that allow for electronically functional particles. The size of the redispersed nanoparticles was small enough to use these suspensions to build interfacial layers in inverted polymer-fullerene solar cells. The performance of these devices was found to depend on the stabilizer used in the nanoparticle suspension. The best performance was obtained with an AZO interfacial layer built with a 3,6,9-trioxadecanoic acid and polyvinylpyrrolidone stabilized nanoparticle suspension. - Highlights: • Preparation of stable aluminum doped zinc oxide nanoparticle suspensions • Different stabilizers were used to stabilize these nanoparticle suspensions. • The material was used as interfacial layers in inverted polymer solar cells. • The performance of these devices depends on the stabilizer used in the suspension.

  6. Laser sintering of magnesia with nanoparticles of iron oxide and aluminum oxide

    International Nuclear Information System (INIS)

    Highlights: • Laser sintered MgO pellets with nanoparticles of Al2O3 and Fe2O3. • Characterized these pellets by XRD, SEM and XPS. • Spinel formations were observed in both cases. • Changes in morphology and structure were analyzed. - Abstract: Nanoparticles of iron oxide (Fe2O3, 20–40 nm) and aluminum oxide (Al2O3, 50 nm) were mixed in different concentrations (3, 5 and 7 wt%) in a magnesium oxide (MgO) matrix. The mixture pellet was irradiated with 532 nm output from a Q-switched Nd:YAG laser using different laser fluence and translation speed for sintering. The refractory samples obtained were analyzed using X-ray diffraction technique, scanning electron microscopy and X-ray photoelectron spectroscopy. The results showed that the samples irradiated at translation speed of 110 μm/s and energy fluence of 1.7 J/cm2 with a concentration of 5 and 7 wt% of Fe2O3 presented the MgFe2O4 spinel-type phase. With the addition of Al2O3 nanoparticles, at a translation speed of 110 μm/s and energy fluence of 1.7 J/cm2, there were the formations of MgAl2O4 spinel phase. The changes in morphologies and microstructure due to laser irradiation were analyzed

  7. Optical Properties of Au Nanoparticles Coated on Surface of Glass or Anodic Aluminum Oxide Template

    Institute of Scientific and Technical Information of China (English)

    FENG Jinyang; WU Can; MA Xiao; ZHANG Hongquan; ZHAO Xiujian

    2012-01-01

    Au nanoparticles coated on the surface of glass (Sample A) or on anodic aluminum oxide template surface (Sample B) were prepared using titanium dioxide sol-gel doped with chloroauric acid and with a reduction process.FE-SEM,UV-Vis spectrum and Fluorescence spectrum tests show that Au nanoparticles have been distributed randomly on the surface of glass,while deposition occurs on the surface of regular hollows for anodic aluminum oxide template.A sharp absorption peak appears at the wavelength of 536 nm for sample B,while there is a red shift,with a broader peak for sample A.A distinct fluorescence emission at the wavelength of 633 nm is detected for sample A,but no noticeable fluorescence emission has been found for Sample B.The results indicate that the microstructure and optical properties of Au nanoparticles can be modulated by different substrate.

  8. Laser sintering of magnesia with nanoparticles of iron oxide and aluminum oxide

    Energy Technology Data Exchange (ETDEWEB)

    García, L.V.; Mendivil, M.I.; Roy, T.K. Das; Castillo, G.A. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Cd. Universitaria, San Nicolas de los Garza, Nuevo Leon 66451 (Mexico); Shaji, S., E-mail: sshajis@yahoo.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Cd. Universitaria, San Nicolas de los Garza, Nuevo Leon 66451 (Mexico); CIIDIT, Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)

    2015-05-01

    Highlights: • Laser sintered MgO pellets with nanoparticles of Al{sub 2}O{sub 3} and Fe{sub 2}O{sub 3}. • Characterized these pellets by XRD, SEM and XPS. • Spinel formations were observed in both cases. • Changes in morphology and structure were analyzed. - Abstract: Nanoparticles of iron oxide (Fe{sub 2}O{sub 3}, 20–40 nm) and aluminum oxide (Al{sub 2}O{sub 3}, 50 nm) were mixed in different concentrations (3, 5 and 7 wt%) in a magnesium oxide (MgO) matrix. The mixture pellet was irradiated with 532 nm output from a Q-switched Nd:YAG laser using different laser fluence and translation speed for sintering. The refractory samples obtained were analyzed using X-ray diffraction technique, scanning electron microscopy and X-ray photoelectron spectroscopy. The results showed that the samples irradiated at translation speed of 110 μm/s and energy fluence of 1.7 J/cm{sup 2} with a concentration of 5 and 7 wt% of Fe{sub 2}O{sub 3} presented the MgFe{sub 2}O{sub 4} spinel-type phase. With the addition of Al{sub 2}O{sub 3} nanoparticles, at a translation speed of 110 μm/s and energy fluence of 1.7 J/cm{sup 2}, there were the formations of MgAl{sub 2}O{sub 4} spinel phase. The changes in morphologies and microstructure due to laser irradiation were analyzed.

  9. Sorption of phenanthrene by dissolved organic matter and its complex with aluminum oxide nanoparticles

    International Nuclear Information System (INIS)

    Intent of this study was to explore the potential application of polymerin, the polymeric, dissolved organic matter fraction from olive oil wastewaters, in technologies aimed at remediating hydrophobic organic compounds (HOCs) point-source pollution. Phenanthrene binding with polymerin was investigated. Moreover, the effect of addition of micro and nanoscale aluminum oxides (Al2O3) was studied, as well as sorption of polymerin on the oxides. Phenanthrene binding capacity by polymerin was notably higher than the sorption capacities for both types of Al2O3 particles. Polymerin sorption on nanoparticles was nearly 100 times higher than microparticles. In a three-phase system, using microparticles, higher phenanthrene sorption was found by adding into water polymerin, oxides and phenanthrene simultaneously. In contrast, using nanoparticles, a considerable enhancement of phenanthrene sorption was shown by adding phenanthrene to a pre-formed and dried polymerin-oxide complex. These findings support the application of polymerin, especially associated with Al2O3 nanoparticles, in remediation of water contaminated with HOCs. This work highlights the significant role of nanoparticles. - Size of aluminum oxides significantly affects sorption of polymerin and phenanthrene

  10. Plasmon-induced optical switching of electrical conductivity in porous anodic aluminum oxide films encapsulated with silver nanoparticle arrays.

    Science.gov (United States)

    Huang, Chen-Han; Lin, Hsing-Ying; Lau, Ben-Chao; Liu, Chih-Yi; Chui, Hsiang-Chen; Tzeng, Yonhua

    2010-12-20

    We report on plasmon induced optical switching of electrical conductivity in two-dimensional (2D) arrays of silver (Ag) nanoparticles encapsulated inside nanochannels of porous anodic aluminum oxide (AAO) films. The reversible switching of photoconductivity greatly enhanced by an array of closely spaced Ag nanoparticles which are isolated from each other and from the ambient by thin aluminum oxide barrier layers are attributed to the improved electron transport due to the localized surface plasmon resonance and coupling among Ag nanoparticles. The photoconductivity is proportional to the power, and strongly dependent on the wavelength of light illumination. With Ag nanoparticles being isolated from the ambient environments by a thin layer of aluminum oxide barrier layer of controlled thickness in nanometers to tens of nanometers, deterioration of silver nanoparticles caused by environments is minimized. The electrochemically fabricated nanostructured Ag/AAO is inexpensive and promising for applications to integrated plasmonic circuits and sensors. PMID:21197062

  11. Electrical properties of aluminum-doped zinc oxide (AZO) nanoparticles synthesized by chemical vapor synthesis

    International Nuclear Information System (INIS)

    Aluminum-doped zinc oxide nanoparticles have been prepared by chemical vapor synthesis, which facilitates the incorporation of a higher percentage of dopant atoms, far above the thermodynamic solubility limit of aluminum. The electrical properties of aluminum-doped and undoped zinc oxide nanoparticles were investigated by impedance spectroscopy. The impedance is measured under hydrogen and synthetic air between 323 and 673 K. The measurements under hydrogen as well as under synthetic air show transport properties depending on temperature and doping level. Under hydrogen atmosphere, a decreasing conductivity with increasing dopant content is observed, which can be explained by enhanced scattering processes due to an increasing disorder in the nanocrystalline material. The temperature coefficient for the doped samples switches from positive temperature coefficient behavior to negative temperature coefficient behavior with increasing dopant concentration. In the presence of synthetic air, the conductivity firstly increases with increasing dopant content by six orders of magnitude. The origin of the increasing conductivity is the generation of free charge carriers upon dopant incorporation. It reaches its maximum at a concentration of 7.7% of aluminum, and drops for higher doping levels. In all cases, the conductivity under hydrogen is higher than under synthetic air and can be changed reversibly by changing the atmosphere.

  12. Modeling of oxidation of aluminum nanoparticles by using Cabrera Mott Model

    Science.gov (United States)

    Ramazanova, Zamart; Zyskin, Maxim; Martirosyan, Karen

    2012-10-01

    Our research focuses on modeling new Nanoenergetic Gas-Generator (NGG) formulations that rapidly release a large amount of gaseous products and generates shock and pressure waves. Nanoenergetic thermite reagents include mixtures of Al and metal oxides such as bismuth trioxide and iodine pentoxide. The research problem is considered a spherically symmetric case and used the Cabrera Mott oxidation model to describe the kinetics of oxide growth on spherical Al nanoparticles for evaluating reaction time which a process of the reaction with oxidizer happens on the outer part of oxide layer of aluminum ions are getting in contact with an oxidizing agent and react. We assumed that a ball of Al of radius 20 to 50 nm is covered by a thin oxide layer 2-4 nm and is surrounded by abundant amount of oxygen stored by oxidizers. The ball is rapidly heated up to ignition temperature to initiate self-sustaining oxidation reaction. As a result highly exothermic reaction is generated. In the oxide layer of excess concentrations of electrons and ions are dependent on the electric field potential with the corresponding of the Gibbs factors and that it conducts to the solution of a nonlinear Poisson equation for the electric field potential in a moving boundary domain. Motion of the boundary is determined by the gradient of a solution on the boundary. We investigated oxidation model numerically, using the COMSOL software utilizing finite element analysis. The computing results demonstrate that oxidation rate increases with the decreasing particle radius.

  13. Effects of reducing solvent on copper, nickel, and aluminum joining using silver nanoparticles derived from a silver oxide paste

    International Nuclear Information System (INIS)

    The effects of reducing solvent on copper, nickel, and aluminum joining using silver nanoparticles derived from a silver oxide paste was investigated by thermal analysis, transmission electron microscopy (TEM) observation, and tensile shear testing. A complete weight loss of diethylene glycol (DEG) in a paste occurred during the redox reaction, whereas a polyethylene glycol 400 (PEG) paste retained the PEG solvent until about 300°C due to its longer carbon chains. Residual PEG in the paste reduced the natural oxide film on copper and nickel substrates during bonding, facilitating a direct sinter of silver nanoparticles to these substrates. On the other hand, silver nanoparticles were sintered to the natural oxide film on an aluminum substrate by the DEG paste. The suitability of the reducing solvent for oxide film reduction of the metal substrate during bonding was explained by an Ellingham diagram. (author)

  14. Determining the Effect of Aluminum Oxide Nanoparticles on the Aggregation of Amyloid-Beta in Transgenic Caenorhabditis elegans

    Science.gov (United States)

    Patel, Suhag; Matticks, John; Howell, Carina

    2014-03-01

    The cause of Alzheimer's disease has been linked partially to genetic factors but the predicted environmental components have yet to be determined. In Alzheimer's, accumulation of amyloid-beta protein in the brain forms plaques resulting in neurodegeneration and loss of mental functions. It has been postulated that aluminum influences the aggregation of amyloid-beta. To test this hypothesis, transgenic Caenorhabditis elegans, CL2120, was used as a model organism to observe neurodegeneration in nematodes exposed to aluminum oxide nanoparticles. Behavioral testing, fluorescent staining, and fluorescence microscopy were used to test the effects of aggregation of amyloid-beta in the nervous systems of effected nematodes exposed to aluminum oxide nanoparticles. Energy-dispersive x-ray spectroscopy was used to quantify the total concentration of aluminum oxide that the worms were exposed to during the experiment. Exposure of transgenic and wild type worms to a concentration of 4 mg mL-1 aluminum oxide showed a decrease in the sinusoidal motion, as well as an infirmity of transgenic worms when compared to control worms. These results support the hypothesis that aluminum may play a role in neurodegeneration in C. elegans, and may influence and increase the progression of Alzheimer's disease. This work was supported by National Science Foundation grants DUE-1058829, DMR-0923047 DUE-0806660 and Lock Haven FPDC grants.

  15. Monolayer-directed Assembly and Magnetic Properties of FePt Nanoparticles on Patterned Aluminum Oxide

    Directory of Open Access Journals (Sweden)

    Guus Rijnders

    2010-03-01

    Full Text Available FePt nanoparticles (NPs were assembled on aluminum oxide substrates, and their ferromagnetic properties were studied before and after thermal annealing. For the first time, phosph(onates were used as an adsorbate to form self-assembled monolayers (SAMs on alumina to direct the assembly of NPs onto the surface. The Al2O3 substrates were functionalized with aminobutylphosphonic acid (ABP or phosphonoundecanoic acid (PNDA SAMs or with poly(ethyleneimine (PEI as a reference. FePt NPs assembled on all of these monolayers, but much less on unmodified Al2O3, which shows that ligand exchange at the NPs is the most likely mechanism of attachment. Proper modification of the Al2O3 surface and controlling the immersion time of the modified Al2O3 substrates into the FePt NP solution resulted in FePt NPs assembly with controlled NP density. Alumina substrates were patterned by microcontact printing using aminobutylphosphonic acid as the ink, allowing local NP assembly. Thermal annealing under reducing conditions (96%N2/4%H2 led to a phase change of the FePt NPs from the disordered FCC phase to the ordered FCT phase. This resulted in ferromagnetic behavior at room temperature. Such a process can potentially be applied in the fabrication of spintronic devices.

  16. Sex-Dependent Depression-Like Behavior Induced by Respiratory Administration of Aluminum Oxide Nanoparticles.

    Science.gov (United States)

    Zhang, Xin; Xu, Yan; Zhou, Lian; Zhang, Chengcheng; Meng, Qingtao; Wu, Shenshen; Wang, Shizhi; Ding, Zhen; Chen, Xiaodong; Li, Xiaobo; Chen, Rui

    2015-12-01

    Ultrafine aluminum oxide, which are abundant in ambient and involved occupational environments, are associated with neurobehavioral alterations. However, few studies have focused on the effect of sex differences following exposure to environmental Al₂O₃ ultrafine particles. In the present study, male and female mice were exposed to Al₂O₃ nanoparticles (NPs) through a respiratory route. Only the female mice showed depression-like behavior. Although no obvious pathological changes were observed in mice brain tissues, the neurotransmitter and voltage-gated ion channel related gene expression, as well as the small molecule metabolites in the cerebral cortex, were differentially modulated between male and female mice. Both mental disorder-involved gene expression levels and metabolomics analysis results strongly suggested that glutamate pathways were implicated in sex differentiation induced by Al₂O₃ NPs. Results demonstrated the potential mechanism of environmental ultrafine particle-induced depression-like behavior and the importance of sex dimorphism in the toxic research of environmental chemicals. PMID:26690197

  17. Sex-Dependent Depression-Like Behavior Induced by Respiratory Administration of Aluminum Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Xin Zhang

    2015-12-01

    Full Text Available Ultrafine aluminum oxide, which are abundant in ambient and involved occupational environments, are associated with neurobehavioral alterations. However, few studies have focused on the effect of sex differences following exposure to environmental Al2O3 ultrafine particles. In the present study, male and female mice were exposed to Al2O3 nanoparticles (NPs through a respiratory route. Only the female mice showed depression-like behavior. Although no obvious pathological changes were observed in mice brain tissues, the neurotransmitter and voltage-gated ion channel related gene expression, as well as the small molecule metabolites in the cerebral cortex, were differentially modulated between male and female mice. Both mental disorder-involved gene expression levels and metabolomics analysis results strongly suggested that glutamate pathways were implicated in sex differentiation induced by Al2O3 NPs. Results demonstrated the potential mechanism of environmental ultrafine particle-induced depression-like behavior and the importance of sex dimorphism in the toxic research of environmental chemicals.

  18. Multimillion atom simulations of dynamics of oxidation of an aluminum nanoparticle and nanoindentation on ceramics.

    Science.gov (United States)

    Vashishta, Priya; Kalia, Rajiv K; Nakano, Aiichiro

    2006-03-01

    We have developed a first-principles-based hierarchical simulation framework, which seamlessly integrates (1) a quantum mechanical description based on the density functional theory (DFT), (2) multilevel molecular dynamics (MD) simulations based on a reactive force field (ReaxFF) that describes chemical reactions and polarization, a nonreactive force field that employs dynamic atomic charges, and an effective force field (EFF), and (3) an atomistically informed continuum model to reach macroscopic length scales. For scalable hierarchical simulations, we have developed parallel linear-scaling algorithms for (1) DFT calculation based on a divide-and-conquer algorithm on adaptive multigrids, (2) chemically reactive MD based on a fast ReaxFF (F-ReaxFF) algorithm, and (3) EFF-MD based on a space-time multiresolution MD (MRMD) algorithm. On 1920 Intel Itanium2 processors, we have demonstrated 1.4 million atom (0.12 trillion grid points) DFT, 0.56 billion atom F-ReaxFF, and 18.9 billion atom MRMD calculations, with parallel efficiency as high as 0.953. Through the use of these algorithms, multimillion atom MD simulations have been performed to study the oxidation of an aluminum nanoparticle. Structural and dynamic correlations in the oxide region are calculated as well as the evolution of charges, surface oxide thickness, diffusivities of atoms, and local stresses. In the microcanonical ensemble, the oxidizing reaction becomes explosive in both molecular and atomic oxygen environments, due to the enormous energy release associated with Al-O bonding. In the canonical ensemble, an amorphous oxide layer of a thickness of approximately 40 angstroms is formed after 466 ps, in good agreement with experiments. Simulations have been performed to study nanoindentation on crystalline, amorphous, and nanocrystalline silicon nitride and silicon carbide. Simulation on nanocrystalline silicon carbide reveals unusual deformation mechanisms in brittle nanophase materials, due to

  19. Metallic nanoparticle shape and size effects on aluminum oxide-induced enhancement of exciton-plasmon coupling and quantum dot emission

    Science.gov (United States)

    Wing, Waylin J.; Sadeghi, Seyed M.; Gutha, Rithvik R.; Campbell, Quinn; Mao, Chuanbin

    2015-09-01

    We investigate the shape and size effects of gold metallic nanoparticles on the enhancement of exciton-plasmon coupling and emission of semiconductor quantum dots induced via the simultaneous impact of metal-oxide and plasmonic effects. This enhancement occurs when metallic nanoparticle arrays are separated from the quantum dots by a layered thin film consisting of a high index dielectric material (silicon) and aluminum oxide. Our results show that adding the aluminum oxide layer can increase the degree of polarization of quantum dot emission induced by metallic nanorods by nearly two times, when these nanorods have large aspect ratios. We show when the aspect ratio of these nanorods is reduced to half, the aluminum oxide loses its impact, leading to no improvement in the degree of polarization. These results suggest that a silicon/aluminum oxide layer can significantly enhance exciton-plasmon coupling when quantum dots are in the vicinity of metallic nanoantennas with high aspect ratios.

  20. Metallic nanoparticle shape and size effects on aluminum oxide-induced enhancement of exciton-plasmon coupling and quantum dot emission

    International Nuclear Information System (INIS)

    We investigate the shape and size effects of gold metallic nanoparticles on the enhancement of exciton-plasmon coupling and emission of semiconductor quantum dots induced via the simultaneous impact of metal-oxide and plasmonic effects. This enhancement occurs when metallic nanoparticle arrays are separated from the quantum dots by a layered thin film consisting of a high index dielectric material (silicon) and aluminum oxide. Our results show that adding the aluminum oxide layer can increase the degree of polarization of quantum dot emission induced by metallic nanorods by nearly two times, when these nanorods have large aspect ratios. We show when the aspect ratio of these nanorods is reduced to half, the aluminum oxide loses its impact, leading to no improvement in the degree of polarization. These results suggest that a silicon/aluminum oxide layer can significantly enhance exciton-plasmon coupling when quantum dots are in the vicinity of metallic nanoantennas with high aspect ratios

  1. Metallic nanoparticle shape and size effects on aluminum oxide-induced enhancement of exciton-plasmon coupling and quantum dot emission

    Energy Technology Data Exchange (ETDEWEB)

    Wing, Waylin J.; Sadeghi, Seyed M., E-mail: seyed.sadeghi@uah.edu; Gutha, Rithvik R.; Campbell, Quinn [Department of Physics, University of Alabama in Huntsville, Huntsville, Alabama 35899 (United States); Mao, Chuanbin [Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma 73019 (United States)

    2015-09-28

    We investigate the shape and size effects of gold metallic nanoparticles on the enhancement of exciton-plasmon coupling and emission of semiconductor quantum dots induced via the simultaneous impact of metal-oxide and plasmonic effects. This enhancement occurs when metallic nanoparticle arrays are separated from the quantum dots by a layered thin film consisting of a high index dielectric material (silicon) and aluminum oxide. Our results show that adding the aluminum oxide layer can increase the degree of polarization of quantum dot emission induced by metallic nanorods by nearly two times, when these nanorods have large aspect ratios. We show when the aspect ratio of these nanorods is reduced to half, the aluminum oxide loses its impact, leading to no improvement in the degree of polarization. These results suggest that a silicon/aluminum oxide layer can significantly enhance exciton-plasmon coupling when quantum dots are in the vicinity of metallic nanoantennas with high aspect ratios.

  2. Characterization of ultrafine aluminum nanoparticles

    International Nuclear Information System (INIS)

    Aluminum nanopowders with particle sizes ranging from ∼25 nm to 80 nm were characterized by a variety of methods. We present and compare the results from common powder characterization techniques including transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), BET gas adsorption surface area analysis, thermogravimetric analysis (TGA), photon correlation spectroscopy (PCS), and low angle laser light scattering (LALLS). Aluminum nanoparticles consist of an aluminum core with an aluminum oxide coating. HRTEM measurements of both the particle diameter and oxide layer thickness tend to be larger than those obtained from BET and TGA. LALLS measurements show a large degree of particle agglomeration in solution; therefore, primary particle sizes could not be determined. Furthermore, results from small-angle scattering techniques (SAS), including small-angle neutron (SANS) and x-ray (SAXS) scattering are presented and show excellent agreement with the BET, TGA, and HRTEM. The suite of analytical techniques presented in this paper can be used as a powerful tool in the characterization of many types of nanosized powders.

  3. Fabrication of silver nanoparticles decorated anodic aluminum oxide as the SERS substrate for the detection of pesticide thiram

    Science.gov (United States)

    Tan, En-zhong

    2015-07-01

    An efficient surface-enhanced Raman scattering (SERS) substrate is developed based on silver nanoparticles decorated anodic aluminum oxide (Ag/AAO). The AAO templates were fabricated using a two-step anodization approach, and silver nanoparticles (AgNPs) were obtained by thermal decomposition of Ag nitrate in AAO. The structure of Ag/AAO hybrid substrate is characterized by scanning electron microscopy (SEM). The results show that the as-prepared SERS substrates consist of high-density AgNPs with sizes of tens of nanometers. The AgNPs are adsorbed on the surface of AAO template in the form of network structure which is called "hot spot". The SERS enhancement ability of the nanostructure is verified using thiram as probing molecules. The limit of detection is as low as 1×10-9 mol/L. The results indicate that the as-prepared substrate possesses excellent SERS sensitivity, high stability and uniformity enhancement.

  4. Silver nanoparticles deposited on anodic aluminum oxide template using magnetron sputtering for surface-enhanced Raman scattering substrate

    Energy Technology Data Exchange (ETDEWEB)

    Wong-ek, Krongkamol [Nanoscience and Technology Program, Chulalongkorn University, Bangkok 10330 (Thailand); Eiamchai, Pitak; Horprathum, Mati; Patthanasettakul, Viyapol [National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Rd., Klong Luang, Pathumthani 12120 (Thailand); Limnonthakul, Puenisara [Department of Physics, Faculty of Science, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand); Chindaudom, Pongpan [National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Rd., Klong Luang, Pathumthani 12120 (Thailand); Nuntawong, Noppadon, E-mail: noppadon.nuntawong@nectec.or.t [National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Rd., Klong Luang, Pathumthani 12120 (Thailand)

    2010-09-30

    Low-cost and highly sensitive surface-enhanced Raman scattering (SERS) substrates have been fabricated by a simple anodizing process and a magnetron sputtering deposition. The substrates, which consist of silver nanoparticles embedded on anodic aluminum oxide (AAO) templates, are investigated by a scanning electron microscope and a confocal Raman spectroscopy. The SERS activities are demonstrated by Raman scattering from adsorbed solutions of methylene blue and pyridine on the SERS substrate surface. The most optimized SERS substrate contains the silver nanoparticles, with a size distribution of 10-30 nm, deposited on the AAO template. From a calculation, the SERS enhancement factor is as high as 8.5 x 10{sup 7}, which suggests strong potentials for direct applications in the chemical detection and analyses.

  5. Reactive self-heating model of aluminum spherical nanoparticles

    OpenAIRE

    Martirosyan, Karen S; Zyskin, Maxim

    2012-01-01

    Aluminum-oxygen reaction is important in many highly energetic, high pressure generating systems. Recent experiments with nanostructured thermites suggest that oxidation of aluminum nanoparticles occurs in a few microseconds. Such rapid reaction cannot be explained by a conventional diffusion-based mechanism. We present a rapid oxidation model of a spherical aluminum nanoparticle, using Cabrera-Mott moving boundary mechanism, and taking self-heating into account. In our model, electric potent...

  6. Aluminum-doped zinc oxide nanoparticles attenuate the TSLP levels via suppressing caspase-1 in activated mast cells.

    Science.gov (United States)

    Kim, Min-Ho; Seo, Jun-Ho; Kim, Hyung-Min; Jeong, Hyun-Ja

    2016-04-01

    Zinc oxide nanoparticles (ZO-NPs) are used as antimicrobials, anti-inflammatories, and to treat cancer. However, although ZO-NPs have excellent efficiency and specificity, their cytotoxicity is higher than that of micron-sized zinc oxide. Doping ZO-NPs with aluminum can improve therapeutic efficacy, but the biological effects and mechanisms involved have not been elucidated. Here, we reported the efficacy of aluminum-doped ZO-NP (AZO) on thymic stromal lymphopoietin (TSLP) production and caspase-1 activation in human mast cell line, HMC-1 cells. AZO significantly reduced TSLP levels as well as interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α without inducing cytotoxicity. Furthermore, AZO more effectively reduced TSLP, IL-6, IL-8, and TNF-α levels than ZO-NP. The levels of inflammatory cytokine mRNA were also reduced by AZO treatment. AZO blocked production of IL-1β and activations of caspase-1 and nuclear factor-κB by inhibiting IκB kinase β and receptor interacting protein 2. In addition, AZO attenuated phosphorylation of mitogen-activated protein kinases, such as extracellular signal-regulated kinase, c-Jun N-terminal kinases, and p38. These findings provide evidence that AZO improves anti-inflammatory properties and offer a safe and effective potential treatment option. PMID:26825457

  7. Integrative functional transcriptomic analyses implicate specific molecular pathways in pulmonary toxicity from exposure to aluminum oxide nanoparticles.

    Science.gov (United States)

    Li, Xiaobo; Zhang, Chengcheng; Bian, Qian; Gao, Na; Zhang, Xin; Meng, Qingtao; Wu, Shenshen; Wang, Shizhi; Xia, Yankai; Chen, Rui

    2016-09-01

    Gene expression profiling has developed rapidly in recent years and it can predict and define mechanisms underlying chemical toxicity. Here, RNA microarray and computational technology were used to show that aluminum oxide nanoparticles (Al2O3 NPs) were capable of triggering up-regulation of genes related to the cell cycle and cell death in a human A549 lung adenocarcinoma cell line. Gene expression levels were validated in Al2O3 NPs exposed A549 cells and mice lung tissues, most of which showed consistent trends in regulation. Gene-transcription factor network analysis coupled with cell- and animal-based assays demonstrated that the genes encoding PTPN6, RTN4, BAX and IER play a role in the biological responses induced by the nanoparticle exposure, which caused cell death and cell cycle arrest in the G2/S phase. Further, down-regulated PTPN6 expression demonstrated a core role in the network, thus expression level of PTPN6 was rescued by plasmid transfection, which showed ameliorative effects of A549 cells against cell death and cell cycle arrest. These results demonstrate the feasibility of using gene expression profiling to predict cellular responses induced by nanomaterials, which could be used to develop a comprehensive knowledge of nanotoxicity. PMID:26830206

  8. Carboxylation and Decarboxylation of Aluminum Oxide Nanoparticles Using Bifunctional Carboxylic Acids and Octylamine

    Directory of Open Access Journals (Sweden)

    Shirin Alexander

    2016-01-01

    Full Text Available The carboxylation of alumina nanoparticles (NPs, with bifunctional carboxylic acids, provides molecular anchors that are used for building more complexed structures via either physisorption or chemisorption. Colloidal suspensions of the NPs may be prepared by covalently bonding a series of carboxylic acids with secondary functional groups (HO2C-R-X to the surface of the NPs: lysine (X = NH2, p-hydroxybenzoic acid (X = OH, fumaric acid (X = CO2H, and 4-formylbenzoic acid (X = C(OH. Subsequent reaction with octylamine at either 25°C or 70°C was investigated. Fourier transform IR-attenuated reflectance spectroscopy (FTIR-ATR, thermogravimetric analysis (TGA, and scanning electron microscopy (SEM along with energy dispersive X-ray (EDX analysis were used to characterize the bifunctionalized monolayers and/or multilayer corona surrounding the alumina NPs and investigate the reaction mechanism of octylamine with the functional groups (X of the NPs. Except for the fumaric functionalized NPs, addition of octylamine to the functionalized NPs leads to removal of excess carboxylic acid corona from the surface via an amide formation. The extent of the multilayer is dependent on the strength of the acid⋯acid interaction.

  9. Aluminum doping tunes band gap energy level as well as oxidative stress-mediated cytotoxicity of ZnO nanoparticles in MCF-7 cells

    Science.gov (United States)

    Akhtar, Mohd Javed; Alhadlaq, Hisham A.; Alshamsan, Aws; Majeed Khan, M. A.; Ahamed, Maqusood

    2015-09-01

    We investigated whether Aluminum (Al) doping tunes band gap energy level as well as selective cytotoxicity of ZnO nanoparticles in human breast cancer cells (MCF-7). Pure and Al-doped ZnO nanoparticles were prepared by a simple sol-gel method. Characterization study confirmed the formation of single phase of AlxZn1-xO nanocrystals with the size range of 33-55 nm. Al-doping increased the band gap energy of ZnO nanoparticles (from 3.51 eV for pure to 3.87 eV for Al-doped ZnO). Al-doping also enhanced the cytotoxicity and oxidative stress response of ZnO nanoparticles in MCF-7 cells. The IC50 for undoped ZnO nanoparticles was 44 μg/ml while for the Al-doped ZnO counterparts was 31 μg/ml. Up-regulation of apoptotic genes (e.g. p53, bax/bcl2 ratio, caspase-3 & caspase-9) along with loss of mitochondrial membrane potential suggested that Al-doped ZnO nanoparticles induced apoptosis in MCF-7 cells through mitochondrial pathway. Importantly, Al-doping did not change the benign nature of ZnO nanoparticles towards normal cells suggesting that Al-doping improves the selective cytotoxicity of ZnO nanoparticles toward MCF-7 cells without affecting the normal cells. Our results indicated a novel approach through which the inherent selective cytotoxicity of ZnO nanoparticles against cancer cells can be further improved.

  10. Burning characteristics of individual aluminum/aluminum oxide particles

    OpenAIRE

    Ruttenberg, Eric C.

    1996-01-01

    Approved for public release; distribution is unlimited An experimental investigation was conducted in which the burning characteristics of individual aluminum/aluminum oxide particles were measured using a windowed combustion bomb at atmospheric pressure and under gravity-fall conditions. A scanning electron microscope (SEM) was used to measure the size distribution of the initial aluminum particles and the aluminum oxide residue. Analysis of the residue indicated that the mass of aluminum...

  11. Ultra-trace determination of arsenic species in environmental waters, food and biological samples using a modified aluminum oxide nanoparticle sorbent and AAS detection after multivariate optimization

    International Nuclear Information System (INIS)

    We describe a simple and efficient method for solid phase extraction and speciation of trace quantities of arsenic. It is based on the use of functionalized aluminum oxide nanoparticles and does not require any oxidation or reduction steps. The experimental parameters affecting extraction and quantitation were optimized using fractional factorial design methods. Adsorbed arsenic was eluted from the sorbent with 1 M hydrochloric acid and determined by graphite furnace atomic absorption spectrometry. Preconcentration factors up to 750 were achieved depending on the sample volume. Studies on potential interferences by various anions and cations showed the method to be highly selective. Under optimum conditions, the calibration plots are linear in the 5.0 to 280 ng L−1 and 8.0 to 260 ng L−1 concentration ranges for As(III) and total arsenic, respectively. The detection limits (calculated for S/N ratios of 3) are 1.81 and 1.97 ng L−1 for As(III) and total arsenic, respectively. The method was successfully applied to the determination and speciation of arsenic in (spiked) environmental, food and biological samples and gave good recoveries. The method was validated using a certified geological reference material. (author)

  12. Oxidation kinetics of aluminum diboride

    Science.gov (United States)

    Whittaker, Michael L.; Sohn, H. Y.; Cutler, Raymond A.

    2013-11-01

    The oxidation characteristics of aluminum diboride (AlB2) and a physical mixture of its constituent elements (Al+2B) were studied in dry air and pure oxygen using thermal gravimetric analysis to obtain non-mechanistic kinetic parameters. Heating in air at a constant linear heating rate of 10 °C/min showed a marked difference between Al+2B and AlB2 in the onset of oxidation and final conversion fraction, with AlB2 beginning to oxidize at higher temperatures but reaching nearly complete conversion by 1500 °C. Kinetic parameters were obtained in both air and oxygen using a model-free isothermal method at temperatures between 500 and 1000 °C. Activation energies were found to decrease, in general, with increasing conversion for AlB2 and Al+2B in both air and oxygen. AlB2 exhibited O2-pressure-independent oxidation behavior at low conversions, while the activation energies of Al+2B were higher in O2 than in air. Differences in the composition and morphology between oxidized Al+2B and AlB2 suggested that Al2O3-B2O3 interactions slowed Al+2B oxidation by converting Al2O3 on aluminum particles into a Al4B2O9 shell, while the same Al4B2O9 developed a needle-like morphology in AlB2 that reduced oxygen diffusion distances and increased conversion. The model-free kinetic analysis was critical for interpreting the complex, multistep oxidation behavior for which a single mechanism could not be assigned. At low temperatures, moisture increased the oxidation rate of Al+2B and AlB2, but both appear to be resistant to oxidation in cool, dry environments.

  13. Oxidation dynamics of aluminum nanorods

    International Nuclear Information System (INIS)

    Aluminum nanorods (Al-NRs) are promising fuels for pyrotechnics due to the high contact areas with oxidizers, but their oxidation mechanisms are largely unknown. Here, reactive molecular dynamics simulations are performed to study thermally initiated burning of oxide-coated Al-NRs with different diameters (D = 26, 36, and 46 nm) in oxygen environment. We found that thinner Al-NRs burn faster due to the larger surface-to-volume ratio. The reaction initiates with the dissolution of the alumina shell into the molten Al core to generate heat. This is followed by the incorporation of environmental oxygen atoms into the resulting Al-rich shell, thereby accelerating the heat release. These results reveal an unexpectedly active role of the alumina shell as a “nanoreactor” for oxidation

  14. Aluminum matrix composites reinforced with alumina nanoparticles

    CERN Document Server

    Casati, Riccardo

    2016-01-01

    This book describes the latest efforts to develop aluminum nanocomposites with enhanced damping and mechanical properties and good workability. The nanocomposites exhibited high strength, improved damping behavior and good ductility, making them suitable for use as wires. Since the production of metal matrix nanocomposites by conventional melting processes is considered extremely problematic (because of the poor wettability of the nanoparticles), different powder metallurgy routes were investigated, including high-energy ball milling and unconventional compaction methods. Special attention was paid to the structural characterization at the micro- and nanoscale, as uniform nanoparticle dispersion in metal matrix is of prime importance. The aluminum nanocomposites displayed an ultrafine microstructure reinforced with alumina nanoparticles produced in situ or added ex situ. The physical, mechanical and functional characteristics of the materials produced were evaluated using different mechanical tests and micros...

  15. Oxidation kinetics of aluminum diboride

    International Nuclear Information System (INIS)

    The oxidation characteristics of aluminum diboride (AlB2) and a physical mixture of its constituent elements (Al+2B) were studied in dry air and pure oxygen using thermal gravimetric analysis to obtain non-mechanistic kinetic parameters. Heating in air at a constant linear heating rate of 10 °C/min showed a marked difference between Al+2B and AlB2 in the onset of oxidation and final conversion fraction, with AlB2 beginning to oxidize at higher temperatures but reaching nearly complete conversion by 1500 °C. Kinetic parameters were obtained in both air and oxygen using a model-free isothermal method at temperatures between 500 and 1000 °C. Activation energies were found to decrease, in general, with increasing conversion for AlB2 and Al+2B in both air and oxygen. AlB2 exhibited O2-pressure-independent oxidation behavior at low conversions, while the activation energies of Al+2B were higher in O2 than in air. Differences in the composition and morphology between oxidized Al+2B and AlB2 suggested that Al2O3–B2O3 interactions slowed Al+2B oxidation by converting Al2O3 on aluminum particles into a Al4B2O9 shell, while the same Al4B2O9 developed a needle-like morphology in AlB2 that reduced oxygen diffusion distances and increased conversion. The model-free kinetic analysis was critical for interpreting the complex, multistep oxidation behavior for which a single mechanism could not be assigned. At low temperatures, moisture increased the oxidation rate of Al+2B and AlB2, but both appear to be resistant to oxidation in cool, dry environments. - Graphical abstract: Isothermal kinetic data for AlB2 in air, showing a constantly decreasing activation energy with increasing conversion. Model-free analysis allowed for the calculation of global kinetic parameters despite many simultaneous mechanisms occurring concurrently. (a) Time–temperature plots, (b) conversion as a function of time, (c) Arrhenius plots used to calculate activation energies, and (d) activation energy

  16. Effects of aluminum oxide nanoparticles on the growth, development, and microRNA expression of tobacco (Nicotiana tabacum.

    Directory of Open Access Journals (Sweden)

    Caitlin E Burklew

    Full Text Available Nanoparticles are a class of newly emerging environmental pollutions. To date, few experiments have been conducted to investigate the effect nanoparticles may have on plant growth and development. It is important to study the effects nanoparticles have on plants because they are stationary organisms that cannot move away from environmental stresses like animals can, therefore they must overcome these stresses by molecular routes such as altering gene expression. microRNAs (miRNA are a newly discovered, endogenous class of post-transcriptional gene regulators that function to alter gene expression by either targeting mRNAs for degradation or inhibiting mRNAs translating into proteins. miRNAs have been shown to mediate abiotic stress responses such as drought and salinity in plants by altering gene expression, however no study has been performed on the effect of nanoparticles on the miRNA expression profile; therefore our aim in this study was to classify if certain miRNAs play a role in plant response to Al(2O(3 nanoparticle stress. In this study, we exposed tobacco (Nicotiana tabacum plants (an important cash crop as well as a model organism to 0%, 0.1%, 0.5%, and 1% Al(2O(3 nanoparticles and found that as exposure to the nanoparticles increased, the average root length, the average biomass, and the leaf count of the seedlings significantly decreased. We also found that miR395, miR397, miR398, and miR399 showed an extreme increase in expression during exposure to 1% Al(2O(3 nanoparticles as compared to the other treatments and the control, therefore these miRNAs may play a key role in mediating plant stress responses to nanoparticle stress in the environment. The results of this study show that Al(2O(3 nanoparticles have a negative effect on the growth and development of tobacco seedlings and that miRNAs may play a role in the ability of plants to withstand stress to Al(2O(3 nanoparticles in the environment.

  17. Photothermally activated motion and ignition using aluminum nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Abboud, Jacques E.; Chong Xinyuan; Zhang Mingjun; Zhang Zhili [Mechanical, Aerospace and Biomedical Engineering Department, University of Tennessee, Knoxville, Tennessee 37996 (United States); Jiang Naibo; Roy, Sukesh [Spectral Energies, LLC, 5100 Springfield Street, Suite 301, Dayton, Ohio 45431 (United States); Gord, James R. [Air Force Research Laboratory, Propulsion Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States)

    2013-01-14

    The aluminum nanoparticles (Al NPs) are demonstrated to serve as active photothermal media, to enhance and control local photothermal energy deposition via the photothermal effect activated by localized surface plasmon resonance (LSPR) and amplified by Al NPs oxidation. The activation source is a 2-AA-battery-powered xenon flash lamp. The extent of the photothermally activated movement of Al NPs can be {approx}6 mm. Ignition delay can be {approx}0.1 ms. Both scanning electron microscopy and energy-dispersive X-ray spectroscopy measurements of motion-only and after-ignition products confirm significant Al oxidation occurs through sintering and bursting after the flash exposure. Simulations suggest local heat generation is enhanced by LSPR. The positive-feedback effects from the local heat generation amplified by Al oxidation produce a large increase in local temperature and pressure, which enhances movement and accelerates ignition.

  18. Photoemission study of tris(8-hydroxyquinoline) aluminum/aluminum oxide/tris(8-hydroxyquinoline) aluminum interface

    International Nuclear Information System (INIS)

    The evolution of the interface electronic structure of a sandwich structure involving aluminum oxide and tris(8-hydroxyquinoline) aluminum (Alq), i.e. (Alq/AlOx/Alq), has been investigated with photoemission spectroscopy. Strong chemical reactions have been observed due to aluminum deposition onto the Alq substrate. The subsequent oxygen exposure releases some of the Alq molecules from the interaction with aluminum. Finally, the deposition of the top Alq layer leads to an asymmetry in the electronic energy level alignment with respect to the AlOx interlayer

  19. Formulation and method for preparing gels comprising hydrous aluminum oxide

    Science.gov (United States)

    Collins, Jack L.

    2014-06-17

    Formulations useful for preparing hydrous aluminum oxide gels contain a metal salt including aluminum, an organic base, and a complexing agent. Methods for preparing gels containing hydrous aluminum oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including aluminum, an organic base, and a complexing agent.

  20. Nanotoxicology of Metal Oxide Nanoparticles

    OpenAIRE

    Amedea B. Seabra; Nelson Durán

    2015-01-01

    This review discusses recent advances in the synthesis, characterization and toxicity of metal oxide nanoparticles obtained mainly through biogenic (green) processes. The in vitro and in vivo toxicities of these oxides are discussed including a consideration of the factors important for safe use of these nanomaterials. The toxicities of different metal oxide nanoparticles are compared. The importance of biogenic synthesized metal oxide nanoparticles has been increasing in recent years; howeve...

  1. Aluminum hydroxide nanoparticles show a stronger vaccine adjuvant activity than traditional aluminum hydroxide microparticles

    OpenAIRE

    Li, Xinran; Aldayel, Abdulaziz M.; Cui, Zhengrong

    2013-01-01

    Aluminum hydroxide is used as a vaccine adjuvant in various human vaccines. Unfortunately, despite its favorable safety profile, aluminum hydroxide can only weakly or moderately potentiate antigen-specific antibody responses. When dispersed in an aqueous solution, aluminum hydroxide forms particulates of 1–20 µm. There is increasing evidence that nanoparticles around or less than 200 nm as vaccine or antigen carriers have a more potent adjuvant activity than large microparticles. In the prese...

  2. 21 CFR 73.1015 - Chromium-cobalt-aluminum oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium-cobalt-aluminum oxide. 73.1015 Section 73... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1015 Chromium-cobalt-aluminum oxide. (a) Identity. The color additive chromium-cobalt-aluminum oxide is a blue-green pigment obtained by calcining...

  3. Size- and shape-controlled synthesis and catalytic performance of iron–aluminum mixed oxide nanoparticles for NO{sub X} and SO{sub 2} removal with hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Jie [School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094 (China); Nanjing AIREP Environmental Protection Technology Co., Ltd., Nanjing, Jiangsu 210091 (China); Zhong, Qin, E-mail: zq304@mail.njust.edu.cn [School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094 (China); Nanjing AIREP Environmental Protection Technology Co., Ltd., Nanjing, Jiangsu 210091 (China); Zhang, Shule; Cai, Wei [School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094 (China); Nanjing AIREP Environmental Protection Technology Co., Ltd., Nanjing, Jiangsu 210091 (China)

    2015-02-11

    Graphical abstract: - Highlights: • The size- and shape-controllable synthesis of NIAO(x/y) is introduced. • The catalytic decomposition of H{sub 2}O{sub 2} on NIAO(x/y) is utilized for NO{sub X} and SO{sub 2} removal. • NIAO(7/3) shows highest NO{sub X} (80%) and SO{sub 2} (100%) removal. • The aluminum dramatically improves the structure and surface properties of catalysts. • The catalytic mechanism and well stability is investigated. - Abstract: A novel, simple, reproducible and low-cost strategy is introduced for the size- and shape-controlled synthesis of iron–aluminum mixed oxide nanoparticles (NIAO(x/y)). The as-synthesized NIAO(x/y) catalyze decomposition of H{sub 2}O{sub 2} yielding highly reactive hydroxyl radicals (·OH) for NO{sub X} and SO{sub 2} removal. 100% SO{sub 2} removal is achieved. NIAO(x/y) with Fe/Al molar ratio of 7/3 (NIAO(7/3)) shows the highest NO{sub X} removal of nearly 80% at >170 °C, whereas much lower NO{sub X} removal (<63%) is obtained for NIAO(3/7). The melting of aluminum oxides in NIAO(7/3) promotes the formation of lamellar products, thus improving the specific surface areas and mesoporous distribution, benefiting the production of ·OH radicals. Furthermore, the NIAO(7/3) leads to the minor increase of points of zero charges (PZC), apparent enhancement of FeOH content and high oxidizing ability of Fe(III), further improving the production of ·OH radicals. However, the NIAO(3/7) results in the formation of aluminum surface-enriched spherical particles, thus decreasing the surface atomic ratio of iron oxides, decreasing ·OH radical production. More importantly, the generation of FeOAl causes the decline of active sites. Finally, the catalytic decomposition of H{sub 2}O{sub 2} on NIAO(x/y) is proposed. And the well catalytic stability of NIAO(7/3) is obtained for evaluation of 30 h.

  4. Aluminum nanoparticle/acrylate copolymer nanocomposites for dielectric elastomers with high dielectric constants

    Science.gov (United States)

    Hu, Wei; Zhang, Suki N.; Niu, Xiaofan; Liu, Chao; Pei, Qibing

    2014-03-01

    Dielectric elastomers are useful for large-strain actuation and energy harvesting. Their application has been limited by their low dielectric constants and consequently high driving voltage. Various fillers with high dielectric constants have been incorporated into different elastomer systems to improve the actuation strain, force output and energy density of the compliant actuators and generators. However, agglomeration may happen in these nanocomposites, resulting in a decrease of dielectric strength, an increase of leakage current, and in many instances the degree of enhancement of the dielectric constant. In this work, we investigated aluminum nanoparticles as nanofillers for acrylate copolymers. This metallic nanoparticle was chosen because the availability of free electrons could potentially provide an infinite value of dielectric constant as opposed to dielectric materials including ferroelectric nanocrystals. Moreover, aluminum nanoparticles have a self-passivated oxide shell effectively preventing the formation of conductive path. The surfaces of the aluminum nanoparticles were functionalized with methacrylate groups to assist the uniform dispersion in organic solutions and additionally enable copolymerization with acrylate copolymer matrix during bulk polymerization, and thus to suppress large range drifting of the nanoparticles. The resulting Al nanoparticle-acrylate copolymer nanocomposites were found to exhibit higher dielectric constant and increased stiffness. The leakage current under high electric fields were significantly lower than nanocomposites synthesized without proper nanoparticle surface modification. The dielectric strengths of the composites were comparable with the pristine polymers. In dielectric actuation evaluation, the actuation force output and energy specific work density were enhanced in the nanocomposites compared to the pristine copolymer.

  5. Nanotoxicology of Metal Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Amedea B. Seabra

    2015-06-01

    Full Text Available This review discusses recent advances in the synthesis, characterization and toxicity of metal oxide nanoparticles obtained mainly through biogenic (green processes. The in vitro and in vivo toxicities of these oxides are discussed including a consideration of the factors important for safe use of these nanomaterials. The toxicities of different metal oxide nanoparticles are compared. The importance of biogenic synthesized metal oxide nanoparticles has been increasing in recent years; however, more studies aimed at better characterizing the potent toxicity of these nanoparticles are still necessary for nanosafely considerations and environmental perspectives. In this context, this review aims to inspire new research in the design of green approaches to obtain metal oxide nanoparticles for biomedical and technological applications and to highlight the critical need to fully investigate the nanotoxicity of these particles.

  6. Monolithic Approach to Oxide Dispersion Strengthened Aluminum Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nassau Stern Company is investigating an approach for manufacturing oxide dispersion strengthened (ODS) aluminum in bulk rather than powder form. The approach...

  7. Synthesis of aluminum nanoparticles capped with copolymerizable epoxides

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Brandon J. [Saint Louis University, Department of Chemistry (United States); Bunker, Christopher E. [Air Force Research Laboratory, Wright-Patterson Air Force Base, Propulsion Directorate (United States); Guliants, Elena A. [University of Dayton Research Institute, Department of Electrical and Computer Engineering (United States); Hayes, Sophia E. [Washington University, Department of Chemistry (United States); Kheyfets, Arthur [Saint Louis University, Department of Chemistry (United States); Wentz, Katherine M. [Washington University, Department of Chemistry (United States); Buckner, Steven W., E-mail: buckners@slu.edu; Jelliss, Paul A., E-mail: jellissp@slu.edu [Saint Louis University, Department of Chemistry (United States)

    2013-06-15

    We report on the synthesis of air-stable aluminum nanoparticles (Al NPs) capped with 1,2-epoxy-9-decene. Long-chain epoxides have proven to be effective capping agents for Al NPs as the epoxide ring is highly susceptible to ring-opening polymerization, leading to the formation of putative polyether loops on the nascent Al NP surface. However, these materials are observed to degrade within several hours to days following exposure to ambient air. By inducing polymerization of the additional terminal alkene functionality on the epoxide, we have produced Al NPs that exhibit both a shelf life of {approx}6 weeks and a high active Al content. Transmission electron microscopy confirms that these spherical nanostructures, {approx}25 nm in diameter, are embedded in a covalently bound polymer matrix that serves as a prophylactic barrier against water/air (H{sub 2}O/O{sub 2}) degradation, and {sup 27}Al solid-state NMR is used to nondestructively confirm the presence of both metallic Al{sup 0} and oxidized Al{sup 3+}. In addition, we have induced polymerization of the epoxide terminal alkene functionality with a long-chain diene monomer, 1,13-tetradecadiene, leading to the formation of Al NPs protected by an extremely hydrophobic polymer matrix. These core-shell nanomaterials also have high active Al contents along with extremely long shelf lives (up to 6 months upon air exposure).

  8. Air-Impregnated Nanoporous Anodic Aluminum Oxide Layers for Enhancing the Corrosion Resistance of Aluminum.

    Science.gov (United States)

    Jeong, Chanyoung; Lee, Junghoon; Sheppard, Keith; Choi, Chang-Hwan

    2015-10-13

    Nanoporous anodic aluminum oxide layers were fabricated on aluminum substrates with systematically varied pore diameters (20-80 nm) and oxide thicknesses (150-500 nm) by controlling the anodizing voltage and time and subsequent pore-widening process conditions. The porous nanostructures were then coated with a thin (only a couple of nanometers thick) Teflon film to make the surface hydrophobic and trap air in the pores. The corrosion resistance of the aluminum substrate was evaluated by a potentiodynamic polarization measurement in 3.5 wt % NaCl solution (saltwater). Results showed that the hydrophobic nanoporous anodic aluminum oxide layer significantly enhanced the corrosion resistance of the aluminum substrate compared to a hydrophilic oxide layer of the same nanostructures, to bare (nonanodized) aluminum with only a natural oxide layer on top, and to the latter coated with a thin Teflon film. The hydrophobic nanoporous anodic aluminum oxide layer with the largest pore diameter and the thickest oxide layer (i.e., the maximized air fraction) resulted in the best corrosion resistance with a corrosion inhibition efficiency of up to 99% for up to 7 days. The results demonstrate that the air impregnating the hydrophobic nanopores can effectively inhibit the penetration of corrosive media into the pores, leading to a significant improvement in corrosion resistance. PMID:26393523

  9. Comparative Assessment of Antimicrobial Efficiency of Ionic Silver, Silver Monoxide, and Metallic Silver Incorporated onto an Aluminum Oxide Nanopowder Carrier

    OpenAIRE

    Agnieszka Maria Jastrzębska; Ewa Karwowska; Andrzej R. Olszyna; Antoni R. Kunicki

    2013-01-01

    The present paper provides comparative assessment of antimicrobial efficiency of ionic silver (Ag+), silver monoxide (Ag2O), and metallic silver (Ag) incorporated onto an aluminum oxide nanopowder carrier (Al2O3). The deposition of Ag+ ions, Ag2O nanoparticles, and Ag nanoparticles on an different phases of aluminum oxide nanopowder carrier was realized using consecutive stages of dry sol-gel method. The Al2O3-Ag+, Al2O3-Ag2O, and Al2O3-Ag nanopowders were widely characterized qualitatively a...

  10. Passivation of aluminum nanoparticles by plasma-enhanced chemical vapor deposition for energetic nanomaterials.

    Science.gov (United States)

    Shahravan, Anaram; Desai, Tapan; Matsoukas, Themis

    2014-05-28

    We have produced passivating coatings on 80-nm aluminum particles by plasma-enhanced chemical vapor deposition (PECVD). Three organic precursors--isopropyl alcohol, toluene, and perfluorodecalin--were used to fabricate thin films with thicknesses ranging from 5 nm to 30 nm. The coated samples and one untreated sample were exposed to 85% humidity at 25 °C for two months, and the active Al content was determined by thermogravimetric analysis (TGA) in the presence of oxygen. The results were compared with an uncoated sample stored in a glovebox under argon for the same period. We find that all three coatings provide protection against humidity, compared to the control, and their efficacy ranks in the following order: isopropyl alcohol plasma polymer coatings of this study are suitable passivating thin film for aluminum nanoparticles by providing protection against oxidation while facilitating the complete oxidation of the metallic core at elevated temperature. PMID:24787245

  11. Fabrication of anodic aluminum oxide with incorporated chromate ions

    Science.gov (United States)

    Stępniowski, Wojciech J.; Norek, Małgorzata; Michalska-Domańska, Marta; Bombalska, Aneta; Nowak-Stępniowska, Agata; Kwaśny, Mirosław; Bojar, Zbigniew

    2012-10-01

    The anodization of aluminum in 0.3 M chromic acid is studied. The influence of operating conditions (like anodizing voltage and electrolyte's temperature) on the nanoporous anodic aluminum oxide geometry (including pore diameter, interpore distance, the oxide layer thickness and pores density) is thoroughly investigated. The results revealed typical correlations of the anodic alumina nanopore geometry with operating conditions, such as linear increase of pore diameter and interpore distance with anodizing voltage. The anodic aluminum oxide is characterized by a low pores arrangement, as determined by Fast Fourier transforms analyses of the FE-SEM images, which translates into a high concentration of oxygen vacancies. Moreover, an optimal experimental condition where chromate ions are being successfully incorporated into the anodic alumina walls, have been determined: the higher oxide growth rate the more chromate ions are being trapped. The trapped chromate ions and a high concentration of oxygen vacancies make the anodic aluminum oxide a promising luminescent material.

  12. Corrosion Prevention of Aluminum Nanoparticles by a Polyurethane Coating

    Directory of Open Access Journals (Sweden)

    Toshiyasu Nishimura

    2014-06-01

    Full Text Available In order to prevent corrosion, aluminum nanoparticles were coated with a polyurethane polymer. The coverage of the polyurethane polymer was controlled from 0 to 100%, which changed the corrosion rate of the nanoparticles quantitatively. The surface of the polymer coating was investigated by Transmission Electron Microscopy (TEM and Atomic Force Microscopy (AFM, and the corrosion resistance of the nanoparticles was estimated by a wet/dry corrosion test on a Pt plate with a NaCl solution. From a TEM with EDAX analysis, the 10 mass% polymer coated Al particles in the synthesis were almost 100% covered on the surface by a polymer film of 10 nm thick. On the other hand, the 3 mass% polymer coated Al was almost 40% covered by a film. In the AFM, the potential around the Al particles had a relatively low value with the polymer coating, which indicated that the conductivity of the Al was isolated from the Pt plate by the polymer. Both the corrosion and H2 evolution reaction rates were quantitatively reduced by the mass% of polymer coating. In the case of the 10 mass% coated sample, there was no corrosion of Al nanoparticles. This fact suggested that the electrochemical reaction was suppressed by the polymer coating. Moreover, the reaction rate of Al nanoparticles was suppressed in proportion to the coverage percentage of the coating. Thus, to conclude, it was found that the corrosion rate of Al nanoparticles could be quantitatively suppressed by the coverage percentage of the polymer coating.

  13. Electrodeposition of Vanadium Oxide/Manganese Oxide Hybrid Thin Films on Nanostructured Aluminum Substrates

    OpenAIRE

    Rehnlund, David; Valvo, Mario; Edström, Kristina; Nyholm, Leif

    2014-01-01

    Electrodeposition of functional coatings on aluminum electrodes in aqueous solutions often is impeded by the corrosion of aluminum. In the present work it is demonstrated that electrodeposition of vanadium, oxide films on nanostructured aluminum substrates can be achieved in acidic electrolytes employing a novel strategy in which a thin interspacing layer of manganese oxide is first electrodeposited on aluminum microrod substrates. Such deposited films, which were studied using SEM, XPS, XRD,...

  14. Computer simulation of the photoluminescence of nanostructured aluminum oxide excited with pulsed synchrotron radiation

    OpenAIRE

    Kortov, V. S.; Spiridonova, T. V.; Zvonarev, S. V.

    2013-01-01

    An algorithm and a program are developed to calculate the photoluminescence (PL) parameters for bulk single-crystal and nanoscale dielectrics excited with pulsed synchrotron radiation. The luminescence spectra of F and F+centers and the PL decay kinetics in single-crystal and nanoscale aluminum-oxide samples containing oxygen anion vacancies are calculated for various nanoparticle sizes. It is shown that a noticeable broadening of the bands and a decrease in the afterglow time is observed for...

  15. Generation of Mn oxides nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Mikuška, Pavel; Večeřa, Zbyněk; Dočekal, Bohumil; Moravec, Pavel

    Prague : Czech Aerosol Society, 2013. B143. ISBN N. [European Aerosol Conference (EAC 2013). 01.09.2013-06.09.2013, Prague] R&D Projects: GA ČR(CZ) GAP503/11/2315 Institutional support: RVO:68081715 ; RVO:67985858 Keywords : inhalation * manganese oxides nanoparticles * chemical composition * synthesis Subject RIV: CB - Analytical Chemistry, Separation; CF - Physical ; Theoretical Chemistry (UCHP-M)

  16. Generation of Mn oxides nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Mikuška, Pavel; Večeřa, Zbyněk; Dočekal, Bohumil; Moravec, Pavel

    Prague : Czech Aerosol Society, 2013. B143. ISBN N. [European Aerosol Conference (EAC 2013). 01.09.2013-06.09.2013, Prague] Institutional support: RVO:68081715 ; RVO:67985858 Keywords : manganese oxides nanoparticles * inhalation * synthesis Subject RIV: CB - Analytical Chemistry, Separation; CF - Physical ; Theoretical Chemistry (UCHP-M) http://eac2013.cz/index.php

  17. Generation of Mn oxides nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Večeřa, Zbyněk; Mikuška, Pavel; Dočekal, Bohumil; Moravec, Pavel

    Praha, 2013. s. 106. ISBN N. [QNano Integrating Conference /2./. 27.02.2013-01.03.2013, Praha] R&D Projects: GA ČR(CZ) GAP503/11/2315; GA ČR(CZ) GBP503/12/G147 Institutional support: RVO:68081715 ; RVO:67985858 Keywords : nanoparticles * manganese oxides Subject RIV: CB - Analytical Chemistry, Separation

  18. Influencing solvent miscibility and aqueous stability of aluminum nanoparticles through surface functionalization with acrylic monomers.

    Science.gov (United States)

    Crouse, Christopher A; Pierce, Christian J; Spowart, Jonathan E

    2010-09-01

    With growing interest in the development of new composite systems for a variety of applications that require easily processable materials and adequate structural properties with high energy densities, we have pursued the chemical functionalization of oxide-passivated aluminum nanoparticles (nAl) using three acrylic monomers, 3-methacryloxypropyltrimethoxysilane (MPS), 2-carboxyethyl acrylate (CEA), and phosphonic acid 2-hydroxyethyl methacrylate ester (PAM), to provide chemical compatibility within various solvent and polymeric systems. Fourier transform infrared and X-ray photoelectron spectroscopy suggest that attachment of MPS and PAM monomers occurs through the formation of bonds directly to the passivated oxide surface upon reaction with surface hydroxyls, whereas CEA monomers interact through the formation of ionic carboxylate binding to aluminum atoms within the oxide. The coated particles demonstrate enhanced miscibility in common organic solvents and monomers; MPS and PAM coatings are additionally shown to inhibit oxidation of the aluminum particles when exposed to aqueous environments at room temperature, and PAM coatings are stable at even elevated temperatures. PMID:20795650

  19. METAL OXIDE NANOPARTICLES

    Energy Technology Data Exchange (ETDEWEB)

    FERNANDEZ-GARCIA,M.; RODGRIGUEZ, J.A.

    2007-10-01

    This chapter covers the fundamental science, synthesis, characterization, physicochemical properties and applications of oxide nanomaterials. Explains fundamental aspects that determine the growth and behavior of these systems, briefly examines synthetic procedures using bottom-up and top-down fabrication technologies, discusses the sophisticated experimental techniques and state of the art theory results used to characterize the physico-chemical properties of oxide solids and describe the current knowledge concerning key oxide materials with important technological applications.

  20. Research on Interpore Distance of Anodic Aluminum Oxide Template

    OpenAIRE

    Liu, Xue-jie; Li, Liang-fang

    2013-01-01

    The relationship between the interpore of anodic aluminum oxide (AAO) template and the influencing factors of electrolyte, temperature and oxidation voltage etc. was researched and summarized in this paper. It was pointed out that the interpore was influenced mostly by electrolyte type and oxidation voltage, and least by the electrolyte concentration and oxidation temperature. The interpore of AAO template increases with the oxidation voltage increases. By adjusting the electrolyte and oxidat...

  1. Modeling the Shock Ignition of a Copper Oxide Aluminum Thermite

    Science.gov (United States)

    Lee, Kibaek; Stewart, D. Scott; Clemenson, Michael; Glumac, Nick; Murzyn, Christopher

    2015-06-01

    An experimental ``striker confinement'' shock compression test was developed in the Glumac-group at the University of Illinois to study ignition and reaction in composite reactive materials. These include thermitic and intermetallic reactive powders. The test places a sample of materials such as a thermite mixture of copper oxide and aluminum powders that are initially compressed to about 80 percent full density. Two RP-80 detonators simultaneously push steel bars into reactive material and the resulting compression causes shock compaction of the material and rapid heating. At that point one observes significant reaction and propagation of fronts. But the fronts are peculiar in that they are comprised of reactive events that can be traced to the reaction/diffusion of the initially separated reactants of copper oxide and aluminum that react at their mutual interfaces that nominally make copper liquid and aluminum oxide products. We discuss our model of the shock ignition of the copper oxide aluminum thermite in the context of the striker experiment and how a Gibbs formulation model, that includes multi-components for liquid and solid phases of aluminum, copper oxide, copper and aluminum oxide can predict the events observed at the particle scale in the experiments. Supported by HDTRA1-10-1-0020 (DTRA), N000014-12-1-0555 (ONR).

  2. Research on the methods to determine metallic aluminum content in aluminum nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chen Liang [State Key Lab of Materials Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Material Structure Department, Changjiang River Scientific Research Institute, Wuhan 430010 (China); Song Wulin, E-mail: wulins@126.com [State Key Lab of Materials Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China) and Analytical and Testing Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Lv Jie [State Key Lab of Materials Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen Xia [Analytical and Testing Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Xie Changsheng [State Key Lab of Materials Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2010-04-15

    The high reactivity of aluminum nanoparticles (ANPs) made the determination of their metallic aluminum (Al) content difficult. Volumetric, thermogravimetry and permanganatometric methods were utilized to determine Al content. The reacted solution after volumetric measurement was further studied by transmission electron microscopy (TEM) and select area electron diffraction (SAED), which revealed that there were unreacted Al particles. Peaks indexed to metallic Al were found in the X-ray diffraction (XRD) pattern of the powders after thermogravimetry analysis (TGA). The side reactions between ANPs and water made the result of permanganatometric measurement underestimated as by the former methods. A modified titration method, using anhydrous alcohol as solvent, was performed to reduce the influence of water. The Al content of the ANPs produced by electro-exploded wire using this method was consistent with the quantitative phase analysis by Rietveld refinement.

  3. Hangzhou Jinjiang Group Shanxi Fusheng Aluminum Phase I 800,000 t/a Aluminum Oxide Project Started Operation

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>On October 19,the Shanxi Province Pinglu County Phase I 800,000t/a Aluminum Oxide Project of Shanxi Fusheng Aluminum Co.,Ltd,a subordinate of Hangzhou Jinjiang Group,started operation.This is the fourth Aluminum oxide project constructed and operated by Jinjiang Group.

  4. Tannin biosynthesis of iron oxide nanoparticles

    Science.gov (United States)

    Herrera-Becerra, R.; Rius, J. L.; Zorrilla, C.

    2010-08-01

    In this work, iron oxide nanoparticles synthesized with gallic acid and tannic acid are characterized using High-Resolution Transmission Electron Microscopy (HRTEM). Its size, form, and structure are compared with nanoparticles obtained previously using alfalfa biomass in order to find a simpler, consistent, and environmentally friendly method in the production of iron oxide nanoparticles.

  5. Preparation of Aluminum Nanomesh Thin Films from an Anodic Aluminum Oxide Template as Transparent Conductive Electrodes

    Science.gov (United States)

    Li, Yiwen; Chen, Yulong; Qiu, Mingxia; Yu, Hongyu; Zhang, Xinhai; Sun, Xiao Wei; Chen, Rui

    2016-02-01

    We have employed anodic aluminum oxide as a template to prepare ultrathin, transparent, and conducting Al films with a unique nanomesh structure for transparent conductive electrodes. The anodic aluminum oxide template is obtained through direct anodization of a sputtered Al layer on a glass substrate, and subsequent wet etching creates the nanomesh metallic film. The optical and conductive properties are greatly influenced by experimental conditions. By tuning the anodizing time, transparent electrodes with appropriate optical transmittance and sheet resistance have been obtained. The results demonstrate that our proposed strategy can serve as a potential method to fabricate low-cost TCEs to replace conventional indium tin oxide materials.

  6. Oxidative stress by inorganic nanoparticles.

    Science.gov (United States)

    Tee, Jie Kai; Ong, Choon Nam; Bay, Boon Huat; Ho, Han Kiat; Leong, David Tai

    2016-05-01

    Metallic and metallic oxide nanoparticles (NPs) have been increasingly used for various bio-applications owing to their unique physiochemical properties in terms of conductivity, optical sensitivity, and reactivity. With the extensive usage of NPs, increased human exposure may cause oxidative stress and lead to undesirable health consequences. To date, various endogenous and exogenous sources of oxidants contributing to oxidative stress have been widely reported. Oxidative stress is generally defined as an imbalance between the production of oxidants and the activity of antioxidants, but it is often misrepresented as a single type of cellular stress. At the biological level, NPs can initiate oxidative stress directly or indirectly through various mechanisms, leading to profound effects ranging from the molecular to the disease level. Such effects of oxidative stress have been implicated owing to their small size and high biopersistence. On the other hand, cellular antioxidants help to counteract oxidative stress and protect the cells from further damage. While oxidative stress is commonly known to exert negative biological effects, measured and intentional use of NPs to induce oxidative stress may provide desirable effects to either stimulate cell growth or promote cell death. Hence, NP-induced oxidative stress can be viewed from a wide paradigm. Because oxidative stress is comprised of a wide array of factors, it is also important to use appropriate assays and methods to detect different pro-oxidant and antioxidant species at molecular and disease levels. WIREs Nanomed Nanobiotechnol 2016, 8:414-438. doi: 10.1002/wnan.1374 For further resources related to this article, please visit the WIREs website. PMID:26359790

  7. Synthesis of high purity metal oxide nanoparticles for optical applications

    Science.gov (United States)

    Baker, C.; Kim, W.; Friebele, E. J.; Villalobos, G.; Frantz, J.; Shaw, L. B.; Sadowski, B.; Fontana, J.; Dubinskii, M.; Zhang, J.; Sanghera, J.

    2014-09-01

    In this paper we present our recent research results in synthesizing various metal oxide nanoparticles for use as laser gain media (solid state as well as fiber lasers) and transparent ceramic windows via two separate techniques, co-precipitation and flame spray pyrolysis. The nanoparticles were pressed into ceramic discs that exhibited optical transmission approaching the theoretical limit and showed very high optical-to-optical lasing slope efficiency. We have also synthesized sesquioxide nanoparticles using a Flame Spray Pyrolysis (FSP) technique that leads to the synthesis of a metastable phase of sesquioxide which allows fabricating excellent optical quality transparent windows with very fine grain sizes. Finally, we present our research in the synthesis of rare earth doped boehmite nanoparticles where the rareearth ion is encased in a cage of aluminum and oxygen to prevent ion-ion proximity and energy transfer. The preforms have been drawn into fibers exhibiting long lifetimes and high laser efficiencies.

  8. Comprehensive Investigation of Silver Nanoparticle/Aluminum Electrodes for Copper Indium Sulfide/Polymer Hybrid Solar Cells

    DEFF Research Database (Denmark)

    Arar, Mario; Pein, Andreas; Haas, Wernfried;

    2012-01-01

    Electrode materials are primarily chosen based on their work function to suit the energy levels of the absorber materials. In this paper, we focus on the modification of aluminum cathodes with a thin silver interlayer (2 nm) in copper indium sulfide/poly[(2,7-silafluorene)-alt-(4,7-di-2-thienyl-2......,1,3-benzothiadiazole)] (PSiF-DBT) nanocomposite solar cells, which improves the fill factor compared to pure aluminum electrodes. A comprehensive structural investigation was performed by means of transmission electron microscopy and time-of-flight secondary ion mass spectrometry revealing the presence of silver...... nanoparticles in an aluminum oxide matrix between the absorber layer and the aluminum cathode. In combination with complementary optical investigations, the origin of the improvement is ascribed to a facilitated charge extraction....

  9. Antitumor Activities of Metal Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Maria Pilar Vinardell

    2015-06-01

    Full Text Available Nanoparticles have received much attention recently due to their use in cancer therapy. Studies have shown that different metal oxide nanoparticles induce cytotoxicity in cancer cells, but not in normal cells. In some cases, such anticancer activity has been demonstrated to hold for the nanoparticle alone or in combination with different therapies, such as photocatalytic therapy or some anticancer drugs. Zinc oxide nanoparticles have been shown to have this activity alone or when loaded with an anticancer drug, such as doxorubicin. Other nanoparticles that show cytotoxic effects on cancer cells include cobalt oxide, iron oxide and copper oxide. The antitumor mechanism could work through the generation of reactive oxygen species or apoptosis and necrosis, among other possibilities. Here, we review the most significant antitumor results obtained with different metal oxide nanoparticles.

  10. Chemical Liquid Phase Deposition of Thin Aluminum Oxide Films

    OpenAIRE

    Sun, Jie; Sun, Yingchun

    2007-01-01

    Thin aluminum oxide films were deposited by a new and simple physicochemical method called chemical liquid phase deposition (CLD) on semiconductor materials. Aluminum sulfate with crystallized water and sodium bicarbonate were used as precursors for film growth, and the control of the system pH value played an important role in this experiment. The growth rate is 12 nm/h at room temperature. Post-growth annealing not only densifies and purifies the films, but results in film crystallization a...

  11. Effect of sealing on the morphology of anodized aluminum oxide

    International Nuclear Information System (INIS)

    Highlights: • We explored structural change of anodizing aluminum oxide induced by sealing. • All sealing methods decrease pore size as shown by X-ray/neutron scattering. • Cold sealing and hot water sealing do not alter the aluminum oxide framework. • Hot nickel acetate sealing both fills the pores and deposits on air oxide interface. • Samples with hot nickel acetate sealing outperform other sealing methods. - Abstract: Ultra-small angle X-ray scattering (USAXS), small-angle neutron scattering (SANS), X-ray reflectometry (XRR) and neutron reflectometry (NR) were used to probe structure evolution induced by sealing of anodized aluminum. While cold nickel acetate sealing and hot-water sealing decrease pore size, these methods do not alter the cylindrical porous framework of the anodic aluminum oxide layer. Hot nickel acetate both fills the pores and deposits on the air surface (air–oxide interface), leading to low porosity and small mean pore radius (39 Å). Electrochemical impedance spectroscopy and direct current polarization show that samples sealed by hot nickel acetate outperform samples sealed by other sealing methods

  12. 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.

  13. Sorption of 90Sr by an aluminum oxide

    International Nuclear Information System (INIS)

    The sorption mechanism of an alkaline-earth bivalent cation on activated aluminum oxide is compared to the sorption mechanism of a monovalent ion. The selective retention of the alkaline-earth cation is made use of to remove trace amounts of Sr90 from radioactive waste waters. A kinetic study is reported, leading to the calculation of an industrial column. (author)

  14. OXYANION SORPTION TO HIGH SURFACE AREA IRON AND ALUMINUM OXIDES

    Science.gov (United States)

    Sorption of selected oxyanions (Mo, As, and P) to high surface area iron and aluminum oxides was investigated using in situ Raman and ATR-FTIR spectroscopy, batch sorption methods, electrophoretic mobility measurements, and surface complexation modeling. In situ ATR-FTIR and Raman spectra were coup...

  15. 21 CFR 73.3110a - Chromium-cobalt-aluminum oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium-cobalt-aluminum oxide. 73.3110a Section... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3110a Chromium-cobalt-aluminum oxide. (a) Identity. The color additive chromium-cobalt-aluminum oxide (Pigment Blue 36) (CAS Reg....

  16. Reduction of Oxidative Melt Loss of Aluminum and Its Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Subodh K. Das; Shridas Ningileri

    2006-03-17

    This project led to an improved understanding of the mechanisms of dross formation. The microstructural evolution in industrial dross samples was determined. Results suggested that dross that forms in layers with structure and composition determined by the local magnesium concentration alone. This finding is supported by fundamental studies of molten metal surfaces. X-ray photoelectron spectroscopy data revealed that only magnesium segregates to the molten aluminum alloy surface and reacts to form a growing oxide layer. X-ray diffraction techniques that were using to investigate an oxidizing molten aluminum alloy surface confirmed for the first time that magnesium oxide is the initial crystalline phase that forms during metal oxidation. The analytical techniques developed in this project are now available to investigate other molten metal surfaces. Based on the improved understanding of dross initiation, formation and growth, technology was developed to minimize melt loss. The concept is based on covering the molten metal surface with a reusable physical barrier. Tests in a laboratory-scale reverberatory furnace confirmed the results of bench-scale tests. The main highlights of the work done include: A clear understanding of the kinetics of dross formation and the effect of different alloying elements on dross formation was obtained. It was determined that the dross evolves in similar ways regardless of the aluminum alloy being melted and the results showed that amorphous aluminum nitride forms first, followed by amorphous magnesium oxide and crystalline magnesium oxide in all alloys that contain magnesium. Evaluation of the molten aluminum alloy surface during melting and holding indicated that magnesium oxide is the first crystalline phase to form during oxidation of a clean aluminum alloy surface. Based on dross evaluation and melt tests it became clear that the major contributing factor to aluminum alloy dross was in the alloys with Mg content. Mg was

  17. Optimization of anodized aluminum oxide pore morphology for GaAs nanowire growth

    Directory of Open Access Journals (Sweden)

    Regine A. Loberternos

    2010-06-01

    Full Text Available Anodic Aluminum oxide films were produced by anodization of sputtered Aluminum thin films on Silicon substrates. The effects of anodization voltage and aqueous oxalic acid solution on the pore diameter and interpore distance were studied. Parameters were sequentially varied to optimize the pore uniformity. Pore morphology was most uniform at 40V anodization voltage and 0.3M solution concentration. Average pore diameter and interpore distance for these parameters are 26.14nm ± 13% and 74.62 ± 8%, respectively. Pore diameter uniformity was further improved by etching with phosphoric acid solution. The AAO films were also successfully used to pattern gold nanoparticle catalysts for the synthesis of semiconductor nanowires.

  18. Effect of processing on structural features of anodic aluminum oxides

    Science.gov (United States)

    Erdogan, Pembe; Birol, Yucel

    2012-09-01

    Morphological features of the anodic aluminum oxide (AAO) templates fabricated by electrochemical oxidation under different processing conditions were investigated. The selection of the polishing parameters does not appear to be critical as long as the aluminum substrate is polished adequately prior to the anodization process. AAO layers with a highly ordered pore distribution are obtained after anodizing in 0.6 M oxalic acid at 20 °C under 40 V for 5 minutes suggesting that the desired pore features are attained once an oxide layer develops on the surface. While the pore features are not affected much, the thickness of the AAO template increases with increasing anodization treatment time. Pore features are better and the AAO growth rate is higher at 20 °C than at 5 °C; higher under 45 V than under 40 V; higher with 0.6 M than with 0.3 M oxalic acid.

  19. 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.

  20. Mechanical and microstructural characterization of aluminum reinforced with carbon-coated silver nanoparticles

    International Nuclear Information System (INIS)

    Composites of pure aluminum with carbon-coated silver nanoparticles (Ag-C NP) of 10 nm in size were prepared by the mechanical milling process. Transmission electron microscopy showed that the Ag-C NP are homogeneously dispersed into the Al matrix, silver nanoparticles do not coalesce, grow or dissolve in the aluminum matrix due the carbon shell. The values of yield strength (σ y), maximum strength (σ max) and micro-hardness Vickers (HVN) of the composites were evaluated and reported as a function of Ag-C NP content. It has been found that the introduction of this type of particles in aluminum strengthen it, increasing all the previous parameters

  1. Development of nanoparticles of alumina by sol-gel method using inorganic aluminum salts as precursors

    International Nuclear Information System (INIS)

    Alumina nanoparticles were synthesized by homogeneous precipitation method from inorganic aluminum salt solutions using urea followed by calcination. The nanoparticles so produced were spherical and acicular with uniform particle size distribution. The process describes synthesis of aluminum hydroxide Al(OH)/sub 3 /and boehmite AIOOH, and their thermal decomposition into alumina (Al/sub 2/O/sub 3)/. The structural and morphological properties of the prepared aluminum hydroxide and Nan crystalline powders were characterized by scanning electron microscopy, differential thermal analysis and thermo gravimetric analysis. (author)

  2. CO oxidation on gold nanoparticles: Theoretical studies

    DEFF Research Database (Denmark)

    Remediakis, Ioannis; Lopez, Nuria; Nørskov, Jens Kehlet

    2005-01-01

    We present a summary of our theoretical results regarding CO oxidation on both oxide-supported and isolated gold nanoparticles. Using Density Functional Theory we have studied the adsorption of molecules and the oxidation reaction of CO on gold clusters. Low-coordinated sites on the gold...

  3. H₂O Dissociation-Induced Aluminum Oxide Growth on Oxidized Al(111) Surfaces.

    Science.gov (United States)

    Liu, Qianqian; Tong, Xiao; Zhou, Guangwen

    2015-12-01

    The interaction of water vapor with amorphous aluminum oxide films on Al(111) is studied using X-ray photoelectron spectroscopy to elucidate the passivation mechanism of the oxidized Al(111) surfaces. Exposure of the aluminum oxide film to water vapor results in self-limiting Al2O3/Al(OH)3 bilayer film growth via counter-diffusion of both ions, Al outward and OH inward, where a thinner starting aluminum oxide film is more reactive toward H2O dissociation-induced oxide growth because of the thickness-dependent ionic transport in the aluminum oxide film. The aluminum oxide film exhibits reactivity toward H2O dissociation in both low-vapor pressure [p(H2O) = 1 × 10(-6) Torr] and intermediate-vapor pressure [p(H2O) = 5 Torr] regimes. Compared to the oxide film growth by exposure to a p(H2O) of 1 × 10(-6) Torr, the exposure to a p(H2O) of 5 Torr results in the formation of a more open structure of the inner Al(OH)3 layer and a more compact outer Al2O3 layer, demonstrating the vapor-pressure-dependent atomic structure in the passivating layer. PMID:26550986

  4. Controllable synthesis of Ag nanorods using a porous anodic aluminum oxide template

    International Nuclear Information System (INIS)

    This paper describes a new approach to the synthesis of Ag nanorods. A solvothermal method was used to make Ag nanoparticles inside anodic aluminum oxide (AAO) templates. The nanoparticles were then annealed at 300 deg. C to produce Ag nanorods. The size of AAO templates, which is focused on in this study, would determine the diameter of Ag nanorods. The product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In this study, a nanorod growth mechanism is deduced, and understanding of the growth of nanorods inside AAO templates is furthered. This work demonstrates that it is possible to make crystalline nanorods that the size can be varied.

  5. Thermocurrent dosimetry with high purity aluminum oxide

    Energy Technology Data Exchange (ETDEWEB)

    Fullerton, G.D.; Cameron, J.R.; Moran, P.R.

    1976-01-01

    The application of thermocurrent (TC) to ionizing radiation dosimetry was studied. It was shown that TC in alumina (Al/sub 2/O/sub 3/) has properties that are suited to personnel dosimetry and environmental monitoring. TC dosimeters were made from thin disks of alumina. Aluminum electrodes were evaporated on each side: on one face a high voltage electrode and on the opposite face a measuring electrode encircled by a guard ring. Exposure to ionizing radiation resulted in stored electrons and holes in metastable trapping sites. The signal was read-out by heating the dosimeter with a voltage source and picnometer connected in series between the opposite electrodes. The thermally remobilized charge caused a transient TC. The thermogram, TC versus time or temperature, is similar to a TL glow curve. Either the peak current or the integrated current is a measure of absorbed dose. Six grades of alumina were studied from a total of four commercial suppliers. All six materials displayed radiation induced TC signals. Sapphire of uv-grade quality from the Adolf Meller Co. (AM) had the best dosimetry properties of those investigated. Sources of interference were studied. Thermal fading, residual signal and radiation damage do not limit TC dosimetry. Ultraviolet light can induce a TC response but it is readily excluded with uv-opaque cladding. Improper surface preparation prior to electrode evaporation was shown to cause interference. A spurious TC signal resulted from polarization of surface contaminants. Spurious TC was reduced by improved cleaning prior to electrode application. Polished surfaces resulted in blocking electrodes and caused a sensitivity shift due to radiation induced thermally activated polarization. This was not observed with rough cut surfaces.

  6. Thermally stimulated luminescence studies in combustion synthesized polycrystalline aluminum oxide

    Indian Academy of Sciences (India)

    K R Nagabhushana; B N Lakshminarasappa; D Revannasiddaiah; Fouran Singh

    2008-08-01

    Synthesis of materials by combustion technique results in homogeneous and fine crystalline product. Further, the technique became more popular since it not only saved time and energy but also was easy to process. Aluminum oxide phosphor was synthesized by using urea as fuel in combustion reaction. Photoluminescence (PL) and thermally stimulated luminescence (TSL) characteristics of -irradiated aluminum oxide samples were studied. A broad PL emission with a peak at ∼ 465 nm and a pair of strong and sharp emissions with peaks at 679 and 695 nm were observed in -rayed samples. The PL intensity was observed to increase with increase in -ray dose. Two prominent and well resolved TSL glows with peaks at 210°C and 365°C were observed in all -irradiated Al2O3 samples. The TSL intensity was also found to increase with increase in -ray dose. The TSL glow curves indicated second order kinetics.

  7. Catalytic Behaviour of Mesoporous Cobalt-Aluminum Oxides for CO Oxidation

    Directory of Open Access Journals (Sweden)

    Ankur Bordoloi

    2014-01-01

    Full Text Available Ordered mesoporous materials are promising catalyst supports due to their uniform pore size distribution, high specific surface area and pore volume, tunable pore sizes, and long-range ordering of the pore packing. The evaporation-induced self-assembly (EISA process was applied to synthesize mesoporous mixed oxides, which consist of cobalt ions highly dispersed in an alumina matrix. The characterization of the mesoporous mixed cobalt-aluminum oxides with cobalt loadings in the range from 5 to 15 wt% and calcination temperatures of 673, 973, and 1073 K indicates that Co2+ is homogeneously distributed in the mesoporous alumina matrix. As a function of the Co loading, different phases are present comprising poorly crystalline alumina and mixed cobalt aluminum oxides of the spinel type. The mixed cobalt-aluminum oxides were applied as catalysts in CO oxidation and turned out to be highly active.

  8. Rheology of suspensions with aluminum nano-particles

    OpenAIRE

    Ulrich Teipel; Ulrich Förter-Barth

    2009-01-01

    Nano-scale aluminum particles are innovative materials increasingly used in energetic formulations. In this contribution, the rheological behavior of suspensions with either paraffin oil or HTPB as the matrix fluid and nano-scale aluminum (ALEX) as the dispersed phase is described and discussed. The paraffin oil/aluminum suspensions exhibit non-Newtonian flow behavior over a wide range of concentrations, whereas the HTPB/aluminum suspensions exhibitNewtonian behavior (i.e. the viscosity is in...

  9. Atomic layer deposited aluminum oxide barrier coatings for packaging materials

    Energy Technology Data Exchange (ETDEWEB)

    Hirvikorpi, Terhi, E-mail: terhi.hirvikorpi@vtt.f [Oy Keskuslaboratorio - Centrallaboratorium Ab (KCL), P.O. Box 70, FI-02151 Espoo (Finland); Vaehae-Nissi, Mika, E-mail: mika.vaha-nissi@vtt.f [Oy Keskuslaboratorio - Centrallaboratorium Ab (KCL), P.O. Box 70, FI-02151 Espoo (Finland); Mustonen, Tuomas, E-mail: tuomas.mustonen@vtt.f [Oy Keskuslaboratorio - Centrallaboratorium Ab (KCL), P.O. Box 70, FI-02151 Espoo (Finland); Iiskola, Eero, E-mail: eero.iiskola@kcl.f [Oy Keskuslaboratorio - Centrallaboratorium Ab (KCL), P.O. Box 70, FI-02151 Espoo (Finland); Karppinen, Maarit, E-mail: maarit.karppinen@tkk.f [Laboratory of Inorganic Chemistry, Department of Chemistry, Helsinki University of Technology, P.O. Box 6100, FI-02015 TKK (Finland)

    2010-03-01

    Thin aluminum oxide coatings have been deposited at a low temperature of 80 {sup o}C on various uncoated papers, polymer-coated papers and boards and plain polymer films using the atomic layer deposition (ALD) technique. The work demonstrates that such ALD-grown Al{sub 2}O{sub 3} coatings efficiently enhance the gas-diffusion barrier performance of the studied porous and non-porous materials towards oxygen, water vapor and aromas.

  10. Effect of aluminum metal surface on oxidation of iodide under gamma irradiation conditions

    International Nuclear Information System (INIS)

    The effects of aluminum surface on I- oxidation under gamma irradiation were investigated. Without irradiation, only O2 oxidized I- at pH < 2, and aluminum expedited the oxidation reaction. With irradiation, the radiolysis products from water and air oxidized I- into I3-. At pH < 2, O2 generated by water radiolysis additionally oxidized I-. However, at pH > 6, the H2O2 radiolysis product reduced I3- into I-. A smaller amount of I3- was observed in pH 1.9 and 3.3 solutions in contact with aluminum under irradiation because oxidants preferentially oxidize aluminum rather than I-. Moreover, for pH < 6.0, even less I3- was formed by aluminum exposed to air because air radiolysis products also preferentially oxidized aluminum. (author)

  11. Rheology of suspensions with aluminum nano-particles

    Directory of Open Access Journals (Sweden)

    Ulrich Teipel

    2009-01-01

    Full Text Available Nano-scale aluminum particles are innovative materials increasingly used in energetic formulations. In this contribution, the rheological behavior of suspensions with either paraffin oil or HTPB as the matrix fluid and nano-scale aluminum (ALEX as the dispersed phase is described and discussed. The paraffin oil/aluminum suspensions exhibit non-Newtonian flow behavior over a wide range of concentrations, whereas the HTPB/aluminum suspensions exhibitNewtonian behavior (i.e. the viscosity is independent of shear stress up to a concentration of 50 vol.% aluminum. Both systems have unusual viscoelastic properties in that their elastic moduli are independent of the solids concentration.

  12. Dextran-modified iron oxide nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Ji(r)í Hradil; Alexander Pisarev; Michal Babi(c); Daniel Horák

    2007-01-01

    Dextran-modified iron oxide nanoparticles were prepared by precipitation of Fe(Ⅱ) and Fe(Ⅲ) salts with ammonium hydroxide by two methods.Iron oxide was precipitated either in the presence of dextran solution, or the dextran solution was added after precipitation. In the second method,the iron oxide particle size and size distribution could be controlled depending on the concentration of dextran in the solution. The nanoparticles were characterized by size-exclusion chromatography, transmission electron microscopy and dynamic light scattering. Optimal conditions for preparation of stable iron oxide colloid particles were determined. The dextran/iron oxide ratio 0-0.16 used in precipitation of iron salts can be recommended for synthesis of nanoparticles suitable for biomedical applications, as the colloid does not contain excess dextran and does not coagulate.

  13. A nine-atom rhodium–aluminum oxide cluster oxidizes five carbon monoxide molecules

    Science.gov (United States)

    Li, Xiao-Na; Zhang, Hua-Min; Yuan, Zhen; He, Sheng-Gui

    2016-01-01

    Noble metals can promote the direct participation of lattice oxygen of very stable oxide materials such as aluminum oxide, to oxidize reactant molecules, while the fundamental mechanism of noble metal catalysis is elusive. Here we report that a single atom of rhodium, a powerful noble metal catalyst, can promote the transfer of five oxygen atoms to oxidize carbon monoxide from a nine-atom rhodium–aluminum oxide cluster. This is a sharp improvement in the field of cluster science where the transfer of at most two oxygen atoms from a doped cluster is more commonly observed. Rhodium functions not only as the preferred trapping site to anchor and oxidize carbon monoxide by the oxygen atoms in direct connection with rhodium but also the primarily oxidative centre to accumulate the large amounts of electrons and the polarity of rhodium is ultimately transformed from positive to negative. PMID:27094921

  14. A nine-atom rhodium-aluminum oxide cluster oxidizes five carbon monoxide molecules.

    Science.gov (United States)

    Li, Xiao-Na; Zhang, Hua-Min; Yuan, Zhen; He, Sheng-Gui

    2016-01-01

    Noble metals can promote the direct participation of lattice oxygen of very stable oxide materials such as aluminum oxide, to oxidize reactant molecules, while the fundamental mechanism of noble metal catalysis is elusive. Here we report that a single atom of rhodium, a powerful noble metal catalyst, can promote the transfer of five oxygen atoms to oxidize carbon monoxide from a nine-atom rhodium-aluminum oxide cluster. This is a sharp improvement in the field of cluster science where the transfer of at most two oxygen atoms from a doped cluster is more commonly observed. Rhodium functions not only as the preferred trapping site to anchor and oxidize carbon monoxide by the oxygen atoms in direct connection with rhodium but also the primarily oxidative centre to accumulate the large amounts of electrons and the polarity of rhodium is ultimately transformed from positive to negative. PMID:27094921

  15. Prediction of new thermodynamically stable aluminum oxides

    CERN Document Server

    Liu, Yue; Wang, Shengnan; Zhu, Qiang; Dong, Xiao; Kresse, Georg

    2015-01-01

    Recently, it has been shown that under pressure, unexpected and counterintuitive chemical compounds become stable. Laser shock experiments (A. Rode, unpublished) on alumina (Al2O3) have shown non-equilibrium decomposition of alumina with the formation of free Al and a mysterious transparent phase. Inspired by these observations, with have explored the possibility of the formation of new chemical compounds in the system Al-O. Using the variable-composition structure prediction algorithm USPEX, in addition to the well-known Al2O3, we have found two extraordinary compounds Al4O7 and AlO2 to be thermodynamically stable in the pressure range 330-443 GPa and above 332 GPa, respectively. Both of these compounds at the same time contain oxide O2- and peroxide O22- ions, and both are insulating. Peroxo-groups are responsible for gap states, which significantly reduce the electronic band gap of both Al4O7 and AlO2.

  16. Anodic Oxidation in Aluminum Electrode by Using Hydrated Amorphous Aluminum Oxide Film as Solid Electrolyte under High Electric Field.

    Science.gov (United States)

    Yao, Manwen; Chen, Jianwen; Su, Zhen; Peng, Yong; Zou, Pei; Yao, Xi

    2016-05-01

    Dense and nonporous amorphous aluminum oxide (AmAO) film was deposited onto platinized silicon substrate by sol-gel and spin coating technology. The evaporated aluminum film was deposited onto the AmAO film as top electrode. The hydrated AmAO film was utilized as a solid electrolyte for anodic oxidation of the aluminum electrode (Al) film under high electric field. The hydrated AmAO film was a high efficiency electrolyte, where a 45 nm thick Al film was anodized completely on a 210 nm thick hydrated AmAO film. The current-voltage (I-V) characteristics and breakdown phenomena of a dry and hydrated 210 nm thick AmAO film with a 150 nm thick Al electrode pad were studied in this work. Breakdown voltage of the dry and hydrated 210 nm thick AmAO film were 85 ± 3 V (405 ± 14 MV m(-1)) and 160 ± 5 V (762 ± 24 MV m(-1)), respectively. The breakdown voltage of the hydrated AmAO film increased about twice, owing to the self-healing behavior (anodic oxidation reaction). As an intuitive phenomenon of the self-healing behavior, priority anodic oxidation phenomena was observed in a 210 nm thick hydrated AmAO film with a 65 nm thick Al electrode pad. The results suggested that self-healing behavior (anodic oxidation reaction) was occurring nearby the defect regions of the films during I-V test. It was an effective electrical self-healing method, which would be able to extend to many other simple and complex oxide dielectrics and various composite structures. PMID:27070754

  17. Method for producing metal oxide nanoparticles

    Science.gov (United States)

    Phillips, Jonathan; Mendoza, Daniel; Chen, Chun-Ku

    2008-04-15

    Method for producing metal oxide nanoparticles. The method includes generating an aerosol of solid metallic microparticles, generating plasma with a plasma hot zone at a temperature sufficiently high to vaporize the microparticles into metal vapor, and directing the aerosol into the hot zone of the plasma. The microparticles vaporize in the hot zone into metal vapor. The metal vapor is directed away from the hot zone and into the cooler plasma afterglow where it oxidizes, cools and condenses to form solid metal oxide nanoparticles.

  18. Radioluminescence of rare-earth doped aluminum oxide

    Energy Technology Data Exchange (ETDEWEB)

    Santiago, M.; Molina, P. [Universidad Nacional del Centro de la Provincia de Buenos Aires, Instituto de Fisica Arroyo Seco, Pinto 399, 7000 Tandil (Argentina); Barros, V. S.; Khoury, H. J.; Elihimas, D. R., E-mail: msantiag@exa.unicen.edu.ar [Universidade Federal de Pernambuco, Departamento de Energia Nuclear, Av. Prof. Luiz Freire 1000, Recife, PE 50740-540 (Brazil)

    2011-10-15

    Carbon-doped aluminum oxide (Al{sub 2}O{sub 3}:C) is one of the most used radioluminescence (Rl) materials for fiberoptic dosimetry due to its high efficiency and commercial availability. However, this compound presents the drawback of emitting in the spectral region, where the spurious radioluminescence of fibers is also important. In this work, the radioluminescence response of rare-earth doped Al{sub 2}O{sub 3} samples has been evaluated. The samples were prepared by mixing stoichiometric amounts of aluminum nitrate, urea and dopants with different amounts of terbium, samarium, cerium and thulium nitrates varying from 0 to 0.15 mo 1%. The influence of the different activators on the Rl spectra has been investigated in order to determine the feasibility of using these compounds for Rl fiberoptic dosimetry. (Author)

  19. CoPt patterned media in anodized aluminum oxide templates

    International Nuclear Information System (INIS)

    Patterned recording media consisting of a vertically aligned array of L10 phase CoPt nanowires embedded in a thin anodized aluminum oxide (AAO) template on silicon has been prepared. A sputter deposited thin film of aluminum on silicon was anodized and a CoPt magnetic alloy was electrodeposited into the pores of the AAO. The vertically aligned arrays of CoPt nanowires were about ∼100 nm tall with ∼20 nm average diameter. Since the CoPt nanowire array is laterally constrained by the surrounding AAO, the nanowire diameter is maintained without coarsening during the L10 phase conversion heat treatment at 700 deg. C. After annealing and conversion to the L10 phase, the ∼20 nm CoPt nanowires exhibit a large coercivity of ∼8 kOe measured in the in-plane and perpendicular directions

  20. Irradiation behavior of uranium oxide - Aluminum dispersion fuel

    International Nuclear Information System (INIS)

    An oxide version of the DART code has been generated in order to assess the irradiation behavior of UO2-Al dispersion fuel. The aluminum-fuel interaction models were developed based on U3O8-Al irradiation data. Deformation of the fuel element occurs due to fuel particle swelling driven by both solid and gaseous fission products and as a consequence of the interaction between the fuel particles and the aluminum matrix. The calculations show that, with the assumption that the correlations derived from U3O8 are valid for UO2, the LEU UO2-Al with a 42% fuel volume loading (4 g U/cm3 ) irradiated at fuel temperatures greater than 413 K should undergo breakaway swelling at core burnups greater than about 1.12 x 1027 fissions m-3 (∼63% 235U burnup). (author)

  1. Chemical Liquid Phase Deposition of Thin Aluminum Oxide Films

    Institute of Scientific and Technical Information of China (English)

    SUN,Jie(孙捷); SUN,Ying-Chun(孙迎春)

    2004-01-01

    Thin aluminum oxide films were deposited by a new and simple physicochemical method called chemical liquid phase deposition (CLD) on semiconductor materials. Aluminum sulfate with crystallized water and sodium bicarbonate were used as precursors for film growth, and the control of the system's pH value played an important role in this experiment. The growth rate is 12 nm/h with the deposition at [Al2(SO4)3]=0.0837 mol·L-1, [NaHCO3]=0.214 mol·L-1, 15 ℃. Post-growth annealing not only densifies and purifies the films, but results in film crystallization as well, Excellent quality of A12O3 films in this work is supported by electron dispersion spectroscopy,Fourier transform infrared spectrum, X-ray diffraction spectrum and scanning electron microscopy photograph.

  2. Inhomogeneous depletion of oxygen ions in metal oxide nanoparticles

    Science.gov (United States)

    Vykhodets, Vladimir B.; Jarvis, Emily A. A.; Kurennykh, Tatiana E.; Beketov, Igor V.; Obukhov, Sviatoslav I.; Samatov, Oleg M.; Medvedev, Anatoly I.; Davletshin, Andrey E.; Whyte, Travis H.

    2016-02-01

    Zirconia and yttria stabilized zirconia (YSZ) have multiple uses, including catalysis, fuel cells, dental applications, and thermal coatings. We employ nuclear reaction analysis to determine elemental composition of YSZ nanoparticles synthesized by laser evaporation including 18O studies to distinguish between oxide and adsorbed oxygen content as a function of surface area. We see dramatic deviation from stoichiometry that can be traced to loss of oxygen from the oxide near the surface of these nanopowders. Density functional calculations are coupled with these experimental studies to explore the electronic structure of nonstoichiometric surfaces achieved through depletion of oxygen. Our results show oxygen-depleted surfaces present under oxygen potentials where stoichiometric, oxygen-terminated surfaces would be favored thermodynamically for crystalline systems. Oxygen depletion at nanopowder surfaces can create effective two-dimensional surface metallic states while maintaining stoichiometry in the underlying nanoparticle core. This insight into nanopowder surfaces applies to dissimilar oxides of aluminum and zirconium indicating synthesis conditions may be more influential than the inherent oxide properties and displaying need for distinct models for nanopowders of these important engineering materials where surface chemistry dominates performance.

  3. Zinc oxide nanoparticles inside microgel

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, M.; Zafeiropoulos, N.; Stamm, M. [Leibniz-Inst. fuer Polymerforschung Dresden e.V., Dresden (Germany); Pich, A. [Inst. fuer Makromolekulare Chemie und Textilchemie, Technische Univ. Dresden (Germany)

    2007-07-01

    We investigate on the synthesis of temperature and pH-sensitive hybrid microgels containing ZnO nanoparticles. The synthesis of ZnO nanoparticles was carried out in the presence of poly(N-vinylcaprolactum-co-acetoacetoxyethylmethacrylate-co-N-[3-(dimethylamino)propyl] methacryl amide)(VCL/AAEM/PDMAPMAm) and it was observed that these microgels act as the container for deposition of ZnO nanoparticles, under the specific reaction conditions, leading to the formation of hybrid microgels. A close relationship between changes in properties of microgels and the loaded ZnO content was reported. Microscopic studies confirmed the inclusion of nanoparticles into microgels. It has been found that prepared microgels have tendency to form composite films on solid substrates after water evaporation, with homogenous distribution of ZnO nanoparticles in polymer matrix. (orig.)

  4. Comparative study of the growth of sputtered aluminum oxide films on organic and inorganic substrates

    OpenAIRE

    Sellner, Stefan; Gerlach, Alexander; Kowarik, Stefan; Schreiber, Frank; Dosch, Helmut; Meyer, Stephan; Pflaum, Jens; Ulbricht, Gerhard

    2007-01-01

    We present a comparative study of the growth of the technologically highly relevant gate dielectric and encapsulation material aluminum oxide in inorganic and also organic heterostructures. Atomic force microscopy studies indicate strong similarities in the surface morphology of aluminum oxide films grown on these chemically different substrates. In addition, from X-ray reflectivity measurements we extract the roughness exponent \\beta of aluminum oxide growth on both substrates. By renormalis...

  5. Effect of aluminum and yttrium doping on zinc sulphide nanoparticles

    Science.gov (United States)

    Sharma, Swati; Kashyap, Jyoti; Gupta, Shubhra; Natasha, Kapoor, A.

    2016-05-01

    In this work, pristine and doped Zinc Sulphide (ZnS) nanoparticles have been synthesized via chemical co-precipitation method. ZnS nanoparticles have been doped with Aluminium (Al) and Yttrium (Y) with doping concentration of 5wt% each. The structural and optical properties of the as prepared nanoparticles have been studied using X-Ray diffraction (XRD) technique and Photoluminescence spectroscopy. Average grain size of 2-3nm is observed through the XRD analysis. Effect of doping on stress, strain and lattice constant of the nanoparticles has also been analyzed. Photoluminescence spectra of the as prepared nanoparticles is enhanced due to Al doping and quenched due to Y doping. EDAX studies confirm the relative doping percentage to be 3.47 % and 3.94% by wt. for Al and Y doped nanoparticles respectively. Morphology of the nanoparticles studied using TEM and SEM indicates uniform distribution of spherical nanoparticles.

  6. Standard specification for nuclear-grade aluminum oxide pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This specification applies to pellets of aluminum oxide that may be ultimately used in a reactor core, for example, as filler or spacers within fuel, burnable poison, or control rods. In order to distinguish between the subject pellets and “burnable poison” pellets, it is established that the subject pellets are not intended to be used as neutron-absorbing material. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

  7. Functionalised silicon oxide nanoparticles for fingermark detection.

    Science.gov (United States)

    Moret, Sébastien; Bécue, Andy; Champod, Christophe

    2016-02-01

    Over the past decade, the use of nanotechnology for fingermark detection has been attracting a lot of attention. A substantial number of nanoparticle types has thus been studied and applied with varying success. However, despite all efforts, few publications present clear supporting evidence of their superiority over standard and commonly used techniques. This paper focuses on a rarely studied type of nanoparticles that regroups all desired properties for effective fingermark detection: silicon oxide. These nanoparticles offer optical and surface properties that can be tuned to provide optimal detection. This study explores their potential as a new method for fingermark detection. Detection conditions, outer functionalisations and optical properties were optimised and a first evaluation of the technique is presented. Dye-doped silicon oxide nanoparticles were assessed against a one-step luminescent cyanoacrylate. Both techniques were compared on natural fingermarks from three donors collected on four different non-porous substrates. On average, the two techniques performed similarly but silicon oxide detected marks with a better homogeneity and was less affected by donor inter-variability. The technique remains to be further optimised and yet silicon oxide nanoparticles already show great promises for effective fingermark detection. PMID:26717406

  8. Chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    Aluminum oxide pellets are used in a reactor core as filler or spacers within fuel, burnable poison, or control rods. In order to be suitable for this purpose, the material must meet certain criteria for impurity content. The test methods in the standard are designed to show whether or not a given material meets these specifications. The following analytical procedures are described in detail: boron by titrimetry; separation of boron by mass spectrometry; isotopic composition by mass spectrometry; separation of halides by pyrohydrolysis; fluoride by ion-selective electrode; chloride, bromide, and iodide by amperometric microtitrimetry; trace elements by emission spectroscopy. (JMT)

  9. Nanosized Cobalt Oxides over Aluminum Monoliths for VOC Oxidation.

    Czech Academy of Sciences Publication Activity Database

    Jirátová, Květa; Kovanda, F.; Klempa, Jan; Balabánová, Jana

    Poznań: Poznan Science and Technology Park, 2016, P61. ISBN N. [Designing New Heterogeneous Catalysts: Faraday Discussion. London (GB), 04.04.2016-06.04.2016] R&D Projects: GA ČR GA14-13750S Institutional support: RVO:67985858 Keywords : cobalt oxides * Al monoliths * catalyst layer Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  10. Formation of anodic aluminum oxide with serrated nanochannels.

    Science.gov (United States)

    Li, Dongdong; Zhao, Liang; Jiang, Chuanhai; Lu, Jia G

    2010-08-11

    We report a simple and robust method to self-assemble porous anodic aluminum oxide membranes with serrated nanochannels by anodizing in phosphoric acid solution. Due to high field conduction and anionic incorporation, an increase of anodizing voltage leads to an increase of the impurity levels and also the field strength across barrier layer. On the basis of both experiment and simulation results, the initiation and formation of serrated channels are attributed to the evolution of oxygen gas bubbles followed by plastic deformation in the oxide film. Alternating anodization in oxalic and phosphoric acids is applied to construct multilayered membranes with smooth and serrated channels, demonstrating a unique way to design and construct a three-dimensional hierarchical system with controllable morphology and composition. PMID:20617804

  11. Interfacial charging phenomena of aluminum (hydr)oxides

    Energy Technology Data Exchange (ETDEWEB)

    Hiemstra, T.; Yong, H.; Van Riemsdijk, W.H.

    1999-08-31

    The interfacial charging of Al(OH){sub 3} (gibbsite and bayerite) and Al{sub 2}O{sub 3} has been studied. For Al(OH){sub 3} it can be shown that the very strong variation in charging behavior for different preparations is related to the relative presence of differently reacting crystal planes. The edge faces of the hexagonal gibbsite crystals are proton reactive over the whole pH range, in contrast to the 001 plane, which is mainly uncharged below pH = 10. On this 001 face only doubly coordinated surface groups are found, in contrast to the edges which also have singly coordinated surface groups. The results are fully in agreement with the predictions of the Multi site complexation (MUSIC) model. The proton adsorption, electrolyte ion adsorption, and shift of the IEP of gibbsite and aluminum oxide have been modeled simultaneously. For gibbsite, the ion pair formation of Na is larger than that of Cl, as is evidenced by modeling the experimentally observed upward shift on the IEP and charge reversal at high electrolyte concentrations. All these experimental results can be satisfactorily modeled with the MUSIC model, including the experimental surface potential of aluminum oxide (ISFET).

  12. Acid monolayer functionalized iron oxide nanoparticle catalysts

    Science.gov (United States)

    Ikenberry, Myles

    Superparamagnetic iron oxide nanoparticle functionalization is an area of intensely active research, with applications across disciplines such as biomedical science and heterogeneous catalysis. This work demonstrates the functionalization of iron oxide nanoparticles with a quasi-monolayer of 11-sulfoundecanoic acid, 10-phosphono-1-decanesulfonic acid, and 11-aminoundecanoic acid. The carboxylic and phosphonic moieties form bonds to the iron oxide particle core, while the sulfonic acid groups face outward where they are available for catalysis. The particles were characterized by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), potentiometric titration, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectrometry (XPS), and dynamic light scattering (DLS). The sulfonic acid functionalized particles were used to catalyze the hydrolysis of sucrose at 80° and starch at 130°, showing a higher activity per acid site than the traditional solid acid catalyst Amberlyst-15, and comparing well against results reported in the literature for sulfonic acid functionalized mesoporous silicas. In sucrose catalysis reactions, the phosphonic-sulfonic nanoparticles (PSNPs) were seen to be incompletely recovered by an external magnetic field, while the carboxylic-sulfonic nanoparticles (CSNPs) showed a trend of increasing activity over the first four recycle runs. Between the two sulfonic ligands, the phosphonates produced a more tightly packed monolayer, which corresponded to a higher sulfonic acid loading, lower agglomeration, lower recoverability through application of an external magnetic field, and higher activity per acid site for the hydrolysis of starch. Functionalizations with 11-aminoundecanoic acid resulted in some amine groups binding to the surfaces of iron oxide nanoparticles. This amine binding is commonly ignored in iron oxide

  13. Corrosion evaluation of zirconium doped oxide coatings on aluminum formed by plasma electrolytic oxidation.

    Science.gov (United States)

    Bajat, Jelena; Mišković-Stanković, Vesna; Vasilić, Rastko; Stojadinović, Stevan

    2014-01-01

    The plasma electrolytic oxidation (PEO) of aluminum in sodium tungstate (Na(2)WO(4) · (2)H(2)O) and Na(2)WO(4) · (2)H(2)O doped with Zr was analyzed in order to obtain oxide coatings with improved corrosion resistance. The influence of current density in PEO process and anodization time was investigated, as well as the influence of Zr, with the aim to find out how they affect the chemical content, morphology, surface roughness, and corrosion stability of oxide coatings. It was shown that the presence of Zr increases the corrosion stability of oxide coatings for all investigated PEO times. Evolution of EIS spectra during the exposure to 3% NaCl, as a strong corrosive agent, indicated the highest corrosion stability for PEO coating formed on aluminum at 70 mA/cm(2) for 2 min in a zirconium containing electrolyte. PMID:25125114

  14. Toxicity of iron oxide nanoparticles against osteoblasts

    International Nuclear Information System (INIS)

    Magnetic nanoparticles have been widely used for tissue repair, magnetic resonance imaging, immunoassays and drug delivery. They are very promising in orthopaedic applications and several magnetic nanoparticles have been exploited for the treatment of orthopaedic disease. Here, we conducted an in vitro study to examine the interaction of magnetic iron oxide nanoparticles with human osteoblasts to evaluate the dose-related toxicity of the nanoparticles on osteoblasts. A transmission electron microscope was used to visualise the internalised magnetic nanoparticles in osteoblasts. The CCK-8 results revealed increased cell viability (107.5 % vitality compared with the control group) when co-cultured at a low concentration (20 μg/mL) and decreased cell viability (59.5 % vitality in a concentration of 300 μg/mL and 25.9 % in 500 μg/mL) when co-cultured in high concentrations. The flow cytometric detection revealed similar results with 5.48 % of apoptosis in a concentration of 20 μg/mL, 23.40 % of apoptosis in a concentration of 300 μg/mL and 28.49 % in a concentration of 500 μg/mL. The disrupted cytoskeleton of osteoblasts was also revealed using a laser scanning confocal microscope. We concluded that use of a low concentration of magnetic iron oxide nanoparticles is important to avoid damage to osteoblasts.

  15. Toxicity of iron oxide nanoparticles against osteoblasts

    Energy Technology Data Exchange (ETDEWEB)

    Shi Sifeng [Shanghai Jiao Tong University, Department of Orthopaedic Surgery, Shanghai Sixth People' s Hospital (China); Jia Jingfu [Shanghai Jiao Tong University, School of Chemistry and Chemical Technology (China); Guo Xiaokui [Shanghai Jiao Tong University School of Medicine, Department of Medical Microbiology and Parasitology, Institutes of Medical Sciences (China); Zhao Yaping [Shanghai Jiao Tong University, School of Chemistry and Chemical Technology (China); Liu Boyu [Shanghai Jiao Tong University School of Medicine, Department of Medical Microbiology and Parasitology, Institutes of Medical Sciences (China); Chen Desheng; Guo Yongyuan; Zhang Xianlong, E-mail: zhangxianlong20101@163.com [Shanghai Jiao Tong University, Department of Orthopaedic Surgery, Shanghai Sixth People' s Hospital (China)

    2012-09-15

    Magnetic nanoparticles have been widely used for tissue repair, magnetic resonance imaging, immunoassays and drug delivery. They are very promising in orthopaedic applications and several magnetic nanoparticles have been exploited for the treatment of orthopaedic disease. Here, we conducted an in vitro study to examine the interaction of magnetic iron oxide nanoparticles with human osteoblasts to evaluate the dose-related toxicity of the nanoparticles on osteoblasts. A transmission electron microscope was used to visualise the internalised magnetic nanoparticles in osteoblasts. The CCK-8 results revealed increased cell viability (107.5 % vitality compared with the control group) when co-cultured at a low concentration (20 {mu}g/mL) and decreased cell viability (59.5 % vitality in a concentration of 300 {mu}g/mL and 25.9 % in 500 {mu}g/mL) when co-cultured in high concentrations. The flow cytometric detection revealed similar results with 5.48 % of apoptosis in a concentration of 20 {mu}g/mL, 23.40 % of apoptosis in a concentration of 300 {mu}g/mL and 28.49 % in a concentration of 500 {mu}g/mL. The disrupted cytoskeleton of osteoblasts was also revealed using a laser scanning confocal microscope. We concluded that use of a low concentration of magnetic iron oxide nanoparticles is important to avoid damage to osteoblasts.

  16. Synthesis of silicon nanotubes with cobalt silicide ends using anodized aluminum oxide template

    International Nuclear Information System (INIS)

    Silicon nanotubes (SiNTs) are compatible with Si-based semiconductor technology. In particular, the small diameters and controllable structure of such nanotubes are remaining challenges. Here we describe a method to fabricate SiNTs intrinsically connected with cobalt silicide ends based on highly ordered anodic aluminum oxide (AAO) templates. Size and growth direction of the SiNTs can be well controlled via the templates. The growth of SiNTs is catalyzed by the Co nanoparticles reduced on the pore walls of the AAO after annealing, with a controllable thickness at a given growth temperature and time. Simultaneously, cobalt silicide forms on the bottom side of the SiNTs.

  17. A study into light scattering and absorption by aluminum nanoparticles in PETN

    International Nuclear Information System (INIS)

    The paper is devoted to experimental and theoretical research into nanopartides' optic properties in pentaerythritol tetranitrate (petn) matrix. A photometric sphere was applied for the transmittance and sum of transmittance and reflectance measurement of petn pressed pellets containing aluminum nanoparticles at the light wavelength 643 nm. The theory of light propagation in terms of spherical harmonics solution of radiative transfer equation in the slab geometry with Fresnel boundary conditions was developed. The properties of aluminum nanoparticles were evaluated in terms of Mie theory. The absorbed energy distribution inside the sample was calculated. It was shown that the Beer's type law is applicable approximately. The apparent light absorption cross section determined, which takes into account both scattering and absorption, is bigger than the geometrical one. The aluminum refractive index value, estimated during comparison of theory with the experimental data, agrees well with the handbook's data

  18. Mechanical and microstructural characterization of aluminum reinforced with carbon-coated silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Sanchez, R. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico)]. E-mail: roberto.martinez@cimav.edu.mx; Reyes-Gasga, J. [Instituto de Fisica, UNAM, Apartado Postal 20-364, 01000 Mexico, D.F. (Mexico); Caudillo, R. [Texas Materials Institute and Chemical Engineering Department, University of Texas at Austin, Austin, TX 78712-1063 (United States); Garcia-Gutierrez, D.I. [Texas Materials Institute and Chemical Engineering Department, University of Texas at Austin, Austin, TX 78712-1063 (United States); Marquez-Lucero, A. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico); Estrada-Guel, I. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico); Mendoza-Ruiz, D.C. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico); Jose Yacaman, M. [Texas Materials Institute and Chemical Engineering Department, University of Texas at Austin, Austin, TX 78712-1063 (United States)

    2007-07-12

    Composites of pure aluminum with carbon-coated silver nanoparticles (Ag-C NP) of 10 nm in size were prepared by the mechanical milling process. Transmission electron microscopy showed that the Ag-C NP are homogeneously dispersed into the Al matrix, silver nanoparticles do not coalesce, grow or dissolve in the aluminum matrix due the carbon shell. The values of yield strength ({sigma} {sub y}), maximum strength ({sigma} {sub max}) and micro-hardness Vickers (HVN) of the composites were evaluated and reported as a function of Ag-C NP content. It has been found that the introduction of this type of particles in aluminum strengthen it, increasing all the previous parameters.

  19. Electrochemical fabrication of CdS/Co nanowire arrays in porous aluminum oxide templates

    CERN Document Server

    Yoon, C H

    2002-01-01

    A procedure for preparing semiconductor/metal nanowire arrays is described, based on a template method which entails electrochemical deposition into nanometer-wide parallel pores of anodic aluminum oxide films on aluminum. Aligned CdS/Co heterostructured nanowires have been prepared by ac electrodeposition in the anodic aluminum oxide templates. By varying the preparation conditions, a variety of CdS/Co nanowire arrays were fabricated, whose dimensional properties could be adjusted.

  20. The Electrical and Mechanical Properties of Porous Anodic 6061-T6 Aluminum Alloy Oxide Film

    OpenAIRE

    Tsung-Chieh Cheng; Chu-Chiang Chou

    2015-01-01

    The properties of the growth of the 6061-T6 aluminum alloy oxide were studied using sulfuric acid anodization. The parameters for the manufacturing process include electrolyte categories, electrolyte concentration, and operating voltages. The results showed that the aluminum oxides obtained by anodization process are mainly amorphous structure and the anodic current density is an important factor affecting the rate of response for oxygen and aluminum ions in barrier. In this experiment, polis...

  1. Development of Pinhole-Free Amorphous Aluminum Oxide Protective Layers for Biomedical Device Applications

    OpenAIRE

    Litvinov, Julia; Wang, Yi-Ju; George, Jinnie; Chinwangso, Pawilai; Brankovic, Stanko; Willson, Richard C.; Litvinov, Dmitri

    2013-01-01

    This paper describes synthesis of ultrathin pinhole-free insulating aluminum oxide layers for electronic device protection in corrosive liquid environments, such as phosphate buffered saline (PBS) or clinical fluids, to enable emerging biomedical applications such as biomolecular sensors. A pinhole-free 25-nm thick amorphous aluminum oxide layer has been achieved using ultra-high vacuum DC magnetron reactive sputtering of aluminum in oxygen/argon plasma followed by oxygen plasma post-processi...

  2. Aluminum Oxide Formation On Fecral Catalyst Support By Electro-Chemical Coating

    Directory of Open Access Journals (Sweden)

    Yang H.S.

    2015-06-01

    Full Text Available FeCrAl is comprised essentially of Fe, Cr, Al and generally considered as metallic substrates for catalyst support because of its advantage in the high-temperature corrosion resistance, high mechanical strength, and ductility. Oxidation film and its adhesion on FeCrAl surface with aluminum are important for catalyst life. Therefore various appropriate surface treatments such as thermal oxidation, Sol, PVD, CVD has studied. In this research, PEO (plasma electrolytic oxidation process was applied to form the aluminum oxide on FeCrAl surface, and the formed oxide particle according to process conditions such as electric energy and oxidation time were investigated. Microstructure and aluminum oxide particle on FeCrAl surface after PEO process was observed by FE-SEM and EDS with element mapping analysis. The study presents possibility of aluminum oxide formation by electro-chemical coating process without any pretreatment of FeCrAl.

  3. Astaxanthin ameliorates aluminum chloride-induced spatial memory impairment and neuronal oxidative stress in mice.

    Science.gov (United States)

    Al-Amin, Md Mamun; Reza, Hasan Mahmud; Saadi, Hasan Mahmud; Mahmud, Waich; Ibrahim, Abdirahman Adam; Alam, Musrura Mefta; Kabir, Nadia; Saifullah, A R M; Tropa, Sarjana Tarannum; Quddus, A H M Ruhul

    2016-04-15

    Aluminum chloride induces neurodegenerative disease in animal model. Evidence suggests that aluminum intake results in the activation of glial cells and generation of reactive oxygen species. By contrast, astaxanthin is an antioxidant having potential neuroprotective activity. In this study, we investigate the effect of astaxanthin on aluminum chloride-exposed behavioral brain function and neuronal oxidative stress (OS). Male Swiss albino mice (4 months old) were divided into 4 groups: (i) control (distilled water), (ii) aluminum chloride, (iii) astaxanthin+aluminum chloride, and (iv) astaxanthin. Two behavioral tests; radial arm maze and open field test were conducted, and OS markers were assayed from the brain and liver tissues following 42 days of treatment. Aluminum exposed group showed a significant reduction in spatial memory performance and anxiety-like behavior. Moreover, aluminum group exhibited a marked deterioration of oxidative markers; lipid peroxidation (MDA), nitric oxide (NO), glutathione (GSH) and advanced oxidation of protein products (AOPP) in the brain. To the contrary, co-administration of astaxanthin and aluminum has shown improved spatial memory, locomotor activity, and OS. These results indicate that astaxanthin improves aluminum-induced impaired memory performances presumably by the reduction of OS in the distinct brain regions. We suggest a future study to determine the underlying mechanism of astaxanthin in improving aluminum-exposed behavioral deficits. PMID:26927754

  4. An investigation of the electrochemical action of the epoxy zinc-rich coatings containing surface modified aluminum nanoparticle

    International Nuclear Information System (INIS)

    Highlights: • Aluminum nanoparticle was modified with amino trimethylene phosphonic acid. • 2 wt% of zinc dust in zinc-rich paint was substituted by aluminum nanoparticles. • Surface modified aluminum nanoparticle improved the cathodic period of protection. • Aluminum nanoparticles enhanced the corrosion protection of the zinc-rich coating. - Abstract: Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2 wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties

  5. A study of hydrogen permeation in aluminum alloy treated by various oxidation processes

    International Nuclear Information System (INIS)

    A set of oxide coatings was formed on the surface of an Al alloy (wt%: Fe, 0.24; Si, 1.16; Cu, 0.05-0.2; Zn, 0.1; Al, residual) by means of various oxidation processes. The hydrogen permeability through the aluminum alloy and its coating materials was determined by a vapor phase permeation technique at temperatures ranging from 400 to 500 C using high-purity H2 (99.9999%) gas with an upstream hydrogen pressure of 104-105 Pa. The experimental results show that the hydrogen permeability through aluminum oxide coating is 100-2000 times lower than that through the aluminum alloy substrate. This means that the aluminum oxide is a significant hydrogen permeation barrier. A high hydrogen permeation resistance was observed in an oxide layer prefilmed in 200 C water, while an anodized aluminum oxide film had a less obstructive effect, possibly caused by the porous structure of the anodic oxide. The hydrogen permeability through films of aluminum oxide was not a simple function of the aluminum-oxide phase configuration. (orig.)

  6. Amorphous coatings deposited on aluminum alloy by plasma electrolytic oxidation

    Institute of Scientific and Technical Information of China (English)

    GUAN Yong-jun; XIA Yuan

    2005-01-01

    Amorphous [Al-Si-O] coatings were deposited on aluminum alloy by plasma electrolytic oxidation (PEO). The process parameters, composition, micrograph, and mechanical property of PEO amorphous coatings were investigated. It is found that the growth rate of PEO coatings reaches 4.44 μm/min if the current density is 0.9 mA/mm2. XRD results show that the PEO coatings are amorphous in the current density range of 0.3 - 0.9mA/mm2. EDS results show that the coatings are composed of O, Si and Al elements. SEM results show that the coatings are porous. Nano indentation results show that the hardness of the coatings is about 3 - 4 times of that of the substrate, while the elastic modulus is about the same with the substrate. Furthermore, a formation mechanism of amorphous PEO coatings was proposed.

  7. Fabrication of YBCO nanowires with anodic aluminum oxide (AAO) template

    Energy Technology Data Exchange (ETDEWEB)

    Dadras, Sedigheh, E-mail: dadras@alzahra.ac.ir; Aawani, Elaheh

    2015-10-15

    We have fabricated YBCO nanowires by using anodic aluminum oxide (AAO) template and sol–gel method, to investigate the fundamental properties of the one-dimensional nanostructure YBCO high-temperature superconductor and enhance its applications. The field-emission scanning electron microscopy and X-ray diffraction pattern results have shown forming of Y-123 nanowires in the template. As an outcome, the YBCO nanowires, prepared by dipping AAO template into YBCO sol method, have average diameter of about 38 nm and length of 1 μm; this is an optimum nanowire sample with larger diameter and length. The resistance–temperature measurement indicates that the onset critical temperature of these samples occurs at 91 K, and the resistance of the optimum sample at onset transition is 10 times lower than the other sample.

  8. Fabrication of Nanostructured PLGA Scaffolds Using Anodic Aluminum Oxide Templates

    CERN Document Server

    Hsueh, Cheng-Chih; Hsu, Shan-Hui; Hung, Huey-Shan

    2008-01-01

    PLGA (poly(lactic-co-glycolic acid)) is one of the most used biodegradable and biocompatible materials. Nanostructured PLGA even has great application potentials in tissue engineering. In this research, a fabrication technique for nanostructured PLGA membrane was investigated and developed. In this novel fabrication approach, an anodic aluminum oxide (AAO) film was use as the template ; the PLGA solution was then cast on it ; the vacuum air-extraction process was applied to transfer the nano porous pattern from the AAO membrane to the PLGA membrane and form nanostures on it. The cell culture experiments of the bovine endothelial cells demonstrated that the nanostructured PLGA membrane can double the cell growing rate. Compared to the conventional chemical-etching process, the physical fabrication method proposed in this research not only is simpler but also does not alter the characteristics of the PLGA. The nanostructure of the PLGA membrane can be well controlled by the AAO temperate.

  9. Chemical Bath Deposition of Aluminum Oxide Buffer on Curved Surfaces for Growing Aligned Carbon Nanotube Arrays.

    Science.gov (United States)

    Wang, Haitao; Na, Chongzheng

    2015-07-01

    Direct growth of vertically aligned carbon nanotube (CNT) arrays on substrates requires the deposition of an aluminum oxide buffer (AOB) layer to prevent the diffusion and coalescence of catalyst nanoparticles. Although AOB layers can be readily created on flat substrates using a variety of physical and chemical methods, the preparation of AOB layers on substrates with highly curved surfaces remains challenging. Here, we report a new solution-based method for preparing uniform layers of AOB on highly curved surfaces by the chemical bath deposition of basic aluminum sulfate and annealing. We show that the thickness of AOB layer can be increased by extending the immersion time of a substrate in the chemical bath, following the classical Johnson-Mehl-Avrami-Kolmogorov crystallization kinetics. The increase of AOB thickness in turn leads to the increase of CNT length and the reduction of CNT curviness. Using this method, we have successfully synthesized dense aligned CNT arrays of micrometers in length on substrates with highly curved surfaces including glass fibers, stainless steel mesh, and porous ceramic foam. PMID:26053766

  10. High-aluminum-affinity silica is a nanoparticle that seeds secondary aluminosilicate formation.

    Directory of Open Access Journals (Sweden)

    Ravin Jugdaohsingh

    Full Text Available Despite the importance and abundance of aluminosilicates throughout our natural surroundings, their formation at neutral pH is, surprisingly, a matter of considerable debate. From our experiments in dilute aluminum and silica containing solutions (pH ~ 7 we previously identified a silica polymer with an extraordinarily high affinity for aluminium ions (high-aluminum-affinity silica polymer, HSP. Here, further characterization shows that HSP is a colloid of approximately 2.4 nm in diameter with a mean specific surface area of about 1,000 m(2 g(-1 and it competes effectively with transferrin for Al(III binding. Aluminum binding to HSP strongly inhibited its decomposition whilst the reaction rate constant for the formation of the β-silicomolybdic acid complex indicated a diameter between 3.6 and 4.1 nm for these aluminum-containing nanoparticles. Similarly, high resolution microscopic analysis of the air dried aluminum-containing silica colloid solution revealed 3.9 ± 1.3 nm sized crystalline Al-rich silica nanoparticles (ASP with an estimated Al:Si ratio of between 2 and 3 which is close to the range of secondary aluminosilicates such as imogolite. Thus the high-aluminum-affinity silica polymer is a nanoparticle that seeds early aluminosilicate formation through highly competitive binding of Al(III ions. In niche environments, especially in vivo, this may serve as an alternative mechanism to polyhydroxy Al(III species binding monomeric silica to form early phase, non-toxic aluminosilicates.

  11. Development of Pinhole-Free Amorphous Aluminum Oxide Protective Layers for Biomedical Device Applications.

    Science.gov (United States)

    Litvinov, Julia; Wang, Yi-Ju; George, Jinnie; Chinwangso, Pawilai; Brankovic, Stanko; Willson, Richard C; Litvinov, Dmitri

    2013-06-15

    This paper describes synthesis of ultrathin pinhole-free insulating aluminum oxide layers for electronic device protection in corrosive liquid environments, such as phosphate buffered saline (PBS) or clinical fluids, to enable emerging biomedical applications such as biomolecular sensors. A pinhole-free 25-nm thick amorphous aluminum oxide layer has been achieved using ultra-high vacuum DC magnetron reactive sputtering of aluminum in oxygen/argon plasma followed by oxygen plasma post-processing. Deposition parameters were optimized to achieve the best corrosion protection of lithographically defined device structures. Electrochemical deposition of copper through the aluminum oxide layers was used to detect the presence (or absence) of pinholes. FTIR, XPS, and spectroscopic ellipsometry were used to characterize the material properties of the protective layers. Electrical resistance of the copper device structures protected by the aluminum oxide layers and exposed to a PBS solution was used as a metric to evaluate the long-term stability of these device structures. PMID:23682201

  12. Catalysis of water oxidation in acetonitrile by iridium oxide nanoparticles

    OpenAIRE

    Hidalgo-Acosta, Jonnathan C.; Méndez, Manuel A.; Scanlon, Micheál D.; Vrubel, Heron; Amstutz, Véronique; Adamiak, Wojciech; Opallo, Marcin; Girault, Hubert H.

    2015-01-01

    Water oxidation catalysed by iridium oxide nanoparticles (IrO2 NPs) in water–acetonitrile mixtures using [RuIII(bpy)3]3+ as oxidant was studied as a function of the water content, the acidity of the reaction media and the catalyst concentration. It was observed that under acidic conditions (HClO4) and at high water contents (80% (v/v)) the reaction is slow, but its rate increases as the water content decreases, reaching a maximum at approximately equimolar proportions (≈25% H2O (v/v)). The re...

  13. In-flight oxidation of aluminum in the twin-wire electric arc process

    Science.gov (United States)

    Guillen, Donna Post; Williams, Brian G.

    2006-03-01

    This paper examines the in-flight oxidation of aluminum sprayed in air using the twin-wire electric arc (TWEA) thermal spray process. Aerodynamic shear at the droplet surface increases the amount of in-flight oxidation by promoting entrainment of the surface oxides within the molten droplet and continually exposing fresh fluid available for oxidation. Mathematical predictions herein confirm experimental measurements that reveal an elevated, nearly constant surface temperature (˜2273 K) of the droplets during flight. The calculated oxide volume fraction of a “typical” droplet with internal circulation compares favorably to the experimentally determined oxide content (3.3 12.7%) for a typical TWEA-sprayed aluminum coating sprayed onto a room temperature substrate. It is concluded that internal circulation within the molten aluminum droplet is a significant source of oxidation. This effect produces an oxide content nearly two orders of magnitude larger than that of a droplet without continual oxidation.

  14. Metal Oxide Nanoparticle Photoresists for EUV Patterning

    KAUST Repository

    Jiang, Jing

    2014-01-01

    © 2014SPST. Previous studies of methacrylate based nanoparticle have demonstrated the excellent pattern forming capability of these hybrid materials when used as photoresists under 13.5 nm EUV exposure. HfO2 and ZrO2 methacrylate resists have achieved high resolution (∼22 nm) at a very high EUV sensitivity (4.2 mJ/cm2). Further investigations into the patterning process suggests a ligand displacement mechanism, wherein, any combination of a metal oxide with the correct ligand could generate patterns in the presence of the suitable photoactive compound. The current investigation extends this study by developing new nanoparticle compositions with transdimethylacrylic acid and o-toluic acid ligands. This study describes their synthesis and patterning performance under 248 nm KrF laser (DUV) and also under 13.5 nm EUV exposures (dimethylacrylate nanoparticles) for the new resist compositions.

  15. 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.

  16. Copper Oxide Nanoparticles Induce Oxidative Stress and Cytotoxicity in Airway Epithelial Cells

    OpenAIRE

    Fahmy, Baher; Cormier, Stephania A

    2009-01-01

    Metal oxide nanoparticles are often used as industrial catalysts and elevated levels of these particles have been clearly demonstrated at sites surrounding factories. To date, limited toxicity data on metal oxide nanoparticles are available. To understand the impact of these airborne pollutants on the respiratory system, airway epithelial (HEp-2) cells were exposed to increasing doses of silicon oxide (SiO2), ferric oxide (Fe2O3) and copper oxide (CuO) nanoparticles, the leading metal oxides ...

  17. Temperature dependence of the aggregation behavior of aluminum nanoparticles on liquid substrate

    International Nuclear Information System (INIS)

    Aluminum (Al) nanoparticle aggregates have been fabricated by thermal evaporation method on silicone oil surfaces at different substrate temperatures. The average diameter and height of the Al nanoparticles, namely Φavg and Havg, are of the order of 101 and 100 nm, respectively. As the substrate temperature Ts increases from 293 to 393 K, to the first order of approximation, Φavg increases exponentially and Havg increases quickly between 333 and 373 K. By transmission electron microscopy measurement, we find that the Al nanoparticles and their aggregates exhibit amorphous structure over the whole temperature range. A simple theoretical model is established to explain the coalescence process of the nanoparticles with Ts

  18. Friction stir spot welding of 2024-T3 aluminum alloy with SiC nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Paidar, Moslem; Sarab, Mahsa Laali [Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2016-01-15

    In this study, the Friction stir spot welding (FSSW) of 2024-T3 aluminum alloy with 1.6 mm thickness was investigated. The effects of the silicon carbide (SiC) nanoparticles on the metallurgical and mechanical properties were discussed. The effects of particles on tension shear and wear tests were also investigated. The process was conducted at a constant rotational speed of 1000 rpm. Results showed that adding SiC nanoparticles to the weld during FSSW had a major effect on the mechanical properties. In fact, the addition of nanoparticles as barriers prevented grain growth in the Stir zone (SZ). The data obtained in the tensile-shear and wear tests showed that tensile-shear load and wear resistance increased with the addition of SiC nanoparticles, which was attributed to the fine grain size produced in the SZ.

  19. Friction stir spot welding of 2024-T3 aluminum alloy with SiC nanoparticles

    International Nuclear Information System (INIS)

    In this study, the Friction stir spot welding (FSSW) of 2024-T3 aluminum alloy with 1.6 mm thickness was investigated. The effects of the silicon carbide (SiC) nanoparticles on the metallurgical and mechanical properties were discussed. The effects of particles on tension shear and wear tests were also investigated. The process was conducted at a constant rotational speed of 1000 rpm. Results showed that adding SiC nanoparticles to the weld during FSSW had a major effect on the mechanical properties. In fact, the addition of nanoparticles as barriers prevented grain growth in the Stir zone (SZ). The data obtained in the tensile-shear and wear tests showed that tensile-shear load and wear resistance increased with the addition of SiC nanoparticles, which was attributed to the fine grain size produced in the SZ

  20. Evaluation of iron oxide nanoparticle biocompatibility.

    Science.gov (United States)

    Hanini, Amel; Schmitt, Alain; Kacem, Kamel; Chau, François; Ammar, Souad; Gavard, Julie

    2011-01-01

    Nanotechnology is an exciting field of investigation for the development of new treatments for many human diseases. However, it is necessary to assess the biocompatibility of nanoparticles in vitro and in vivo before considering clinical applications. Our characterization of polyol-produced maghemite γ-Fe(2)O(3) nanoparticles showed high structural quality. The particles showed a homogeneous spherical size around 10 nm and could form aggregates depending on the dispersion conditions. Such nanoparticles were efficiently taken up in vitro by human endothelial cells, which represent the first biological barrier to nanoparticles in vivo. However, γ-Fe(2)O(3) can cause cell death within 24 hours of exposure, most likely through oxidative stress. Further in vivo exploration suggests that although γ-Fe(2)O(3) nanoparticles are rapidly cleared through the urine, they can lead to toxicity in the liver, kidneys and lungs, while the brain and heart remain unaffected. In conclusion, γ-Fe(2)O(3) could exhibit harmful properties and therefore surface coating, cellular targeting, and local exposure should be considered before developing clinical applications. PMID:21589646

  1. Photochemistry of adsorbed nitrate on aluminum oxide particle surfaces.

    Science.gov (United States)

    Rubasinghege, Gayan; Grassian, Vicki H

    2009-07-01

    Nitrogen oxides, including nitrogen dioxide and nitric acid, react with mineral dust particles in the atmosphere to yield adsorbed nitrate. Although nitrate ion is a well-known chromophore in natural waters, little is known about the surface photochemistry of nitrate adsorbed on mineral particles. In this study, nitrate adsorbed on aluminum oxide, a model system for mineral dust aerosol, is irradiated with broadband light (lambda > 300 nm) as a function of relative humidity (RH) in the presence of molecular oxygen. Upon irradiation, the nitrate ion readily undergoes photolysis to yield nitrogen-containing gas-phase products including NO(2), NO, and N(2)O, with NO being the major product. The relative ratio and product yields of these gas-phase products change with RH, with N(2)O production being highest at the higher relative humidities. Furthermore, an efficient dark reaction readily converts the major NO product into NO(2) during post-irradiation. Photochemical processes on mineral dust aerosol surfaces have the potential to impact the chemical balance of the atmosphere, yet little is known about these processes. In this study, the impact that adsorbed nitrate photochemistry may have on the renoxification of the atmosphere is discussed. PMID:19534452

  2. Lactobacillus Mediated Synthesis of Silver Oxide Nanoparticles

    OpenAIRE

    Dhoondia, Zuzer H.; Hemlatta Chakraborty

    2012-01-01

    The ability of prokaryotic microorganisms to reduce the inorganic metals has opened up an exciting eco‐friendly approach towards the development of natural ‘nano‐factories’. However, a number of issues have to be addressed from the nanotechnological and microbiological point of view before such a biosynthesis approach can compete with the existing physical and chemical methods. This report investigates the synthesis of silver oxide nanoparticles using Lactobacillus mindensis, isolated using f...

  3. Aluminum ions accelerated the oxidative stress of copper-mediated melanin formation

    Science.gov (United States)

    Di, Junwei; Bi, Shuping

    2003-11-01

    A comparison between the effects of aluminum and cupric ions on the dopachrome (DC) conversion and the cooperation effect of the both ions in the DOPA oxidation to melanin pathway has been studied by UV-Vis spectrophotometric method. Both aluminum and cupric ions catalyze the DC conversion reaction, which is an important step in the melanin synthesis pathway. However, cupric ions catalyze the conversion of DC to yield 5,6-dihydroxyindole-2-carboxylic acid (DHICA) but the product of DC conversion catalyzed by aluminum is 5,6-dihydroxyindole (DHI). DOPA oxidation catalyzed by aluminum and cupric ions is studied in the presence of hydrogen peroxide. The results from our experiments provide evidence that aluminum can markedly increase the oxidative stress of copper-mediated the melanin formation and influence the properties of the melanin by means of changing the ratio of DHICA/DHI in the acidic environment (pH 5.5).

  4. Analytic Force Field for Clusters and Nanoparticles of Aluminum and Its Hydride

    Science.gov (United States)

    Zhang, Qingfan; Tang, Enoch; Xi, Yongjie; Han, Bo; Legenski, Nicole; Chalas, Guadalupe; Chan, Frankie; Cheng, Hansong; Forrey, Robert C.

    2014-06-01

    An analytic potential energy function is developed for simulating clusters and nanoparticles of aluminum and its hydride. An embedded-atom method is used which modulates the background electron density as a function of the number of nearest-neighbor atoms. The method is parametrized and tested using an extensive training set computed from first-principle density-functional theory. The potential energy function is found to be reliable for clusters of arbitrary size, shape, and composition ratio. The force field obtained from the analytic potential energy function is computationally efficient and well suited for simulating large systems of aluminum and aluminum hydride particles. A proposed molecular dynamics simulation related to hydrogen-storage technologies for onboard automotive applications is briefly discussed.

  5. Numerical modeling of the dispersion of ceramic nanoparticles during ultrasonic processing of aluminum-based nanocomposites

    OpenAIRE

    Daojie Zhang; Laurentiu Nastac

    2014-01-01

    The metal–matrix-nano-composites (MMNCs) in this study consist of a 6061 alloy matrix reinforced with 1.0 wt.% SiC nanoparticles that are dispersed within the matrix using an ultrasonic cavitation dispersion technique available in the Solidification Laboratory at the University of Alabama. The required ultrasonic parameters to achieve (i) the required stirring and cavitation for suitable degassing and refining of the aluminum alloy and (ii) the adequate fluid flow characteristics for unifo...

  6. Preparation of uniform nanoparticles of ultra-high purity metal oxides, mixed metal oxides, metals, and metal alloys

    Science.gov (United States)

    Woodfield, Brian F.; Liu, Shengfeng; Boerio-Goates, Juliana; Liu, Qingyuan; Smith, Stacey Janel

    2012-07-03

    In preferred embodiments, metal nanoparticles, mixed-metal (alloy) nanoparticles, metal oxide nanoparticles and mixed-metal oxide nanoparticles are provided. According to embodiments, the nanoparticles may possess narrow size distributions and high purities. In certain preferred embodiments, methods of preparing metal nanoparticles, mixed-metal nanoparticles, metal oxide nanoparticles and mixed-metal nanoparticles are provided. These methods may provide tight control of particle size, size distribution, and oxidation state. Other preferred embodiments relate to a precursor material that may be used to form nanoparticles. In addition, products prepared from such nanoparticles are disclosed.

  7. Effect of anneal pre-treatment of polycrystalline aluminum sheets on synthesis of highly-ordered anodic aluminum oxide membranes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Anodic aluminum oxide (AAO) membranes with large ordered pore domains were successfully prepared by adopting the anneal pre-treatment of polycrystalline alu- minum sheets. A statistical method with Gaussian distribution was introduced to quantitatively study the size of the domain with ordered pores. The largest average area of ordered pore domains was 2.6 μm2±0.11 μm2. The corresponding AAO membrane was synthesized by aluminum sheets annealed at 893 K for 24 h.

  8. A Theoretical Framework for Predicting the Oxidative Stress Potential of Oxide Nanoparticles

    OpenAIRE

    BURELLO ENRICO; Worth, Andrew

    2010-01-01

    In this paper we propose a theoretical model that predicts the oxidative stress potential of oxide nanoparticles by looking at the ability of these materials to perturb the intracellular redox state. The model uses reactivity descriptors to build the energy band structure of oxide nanoparticles and predicts their ability to induce an oxidative stress by comparing the redox potentials of relevant intracellular reactions with the oxides' energy structure. We find that nanoparticles displaying b...

  9. Ultrasmall lanthanide oxide nanoparticles for biomedical imaging and therapy

    CERN Document Server

    Lee, Gang Ho

    2014-01-01

    Most books discuss general and broad topics regarding molecular imagings. However, Ultrasmall Lanthanide Oxide Nanoparticles for Biomedical Imaging and Therapy, will mainly focus on lanthanide oxide nanoparticles for molecular imaging and therapeutics. Multi-modal imaging capabilities will discussed, along with up-converting FI by using lanthanide oxide nanoparticles. The synthesis will cover polyol synthesis of lanthanide oxide nanoparticles, Surface coatings with biocompatible and hydrophilic ligands will be discussed and TEM images and dynamic light scattering (DLS) patterns will be

  10. Surface enhanced Raman scattering of biospecies on anodized aluminum oxide films

    Science.gov (United States)

    Zhang, C.; Smirnov, A. I.; Hahn, D.; Grebel, H.

    2007-06-01

    Traditionally, aluminum and anodized aluminum oxide films (AAO) are not the platforms of choice for surface-enhanced raman scattering (SERS) experiments despite of the aluminum's large negative permittivity value. Here we examine the usefulness of aluminum and nanoporous alumina platforms for detecting soft biospecies ranging from bacterial spores to protein markers. We used these flat platforms to examine SERS of a model protein (cytochrome c from bovine heart tissue) and bacterial cells (spores of Bacillus subtilis ATCC13933 used as Anthrax simulant) and demonstrated clear Raman amplification.

  11. Discharge behaviors during plasma electrolytic oxidation on aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Run [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Zhenjiang Watercraft College, Zhenjiang 212000, Jiangsu (China); Wu, Jie [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Xue, Wenbin, E-mail: xuewb@bnu.edu.cn [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Qu, Yao; Yang, Chaolin; Wang, Bin; Wu, Xianying [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2014-11-14

    A plasma electrolytic oxidation (PEO) process was performed on the 2024 aluminum alloy in silicate electrolyte to fabricate ceramic coatings under a constant voltage. Optical emission spectroscopy (OES) was employed to evaluate the characteristics of plasma discharge during PEO process. The plasma electron temperature and density were obtained by analyzing the spectral lines of OES, and the atomic ionization degree in discharge zone was calculated in terms of Saha thermal ionization equation. The illumination intensity of plasma discharge and the temperature in the interior of alloy were measured. Combining the surface morphology and cross-sectional microstructure with the optical emission spectra and illumination at different discharge stage, a discharge model in the growth of PEO ceramic coatings was proposed. It is found that there are two discharge modes of type A with small spark size and type B with large spark size, and the latter only appears in the intermediate stage of PEO process. The illumination intensity has a maximum value in the initial stage of oxidation with many sparks of discharge type A. The electron temperature in plasma discharge zone is about 3000 K–7000 K and atomic ionization degree of Al is about 2.0 × 10{sup −5}–7.2 × 10{sup −3}, which depend on discharge stage. The discharge type B plays a key role on the electron temperature and atomic ionization degree. The electron density keeps stable in the range of about 8.5 × 10{sup 21} m{sup −3}–2.6 × 10{sup 22} m{sup −3}. - Highlights: • The characteristics of PEO plasma discharge was evaluated by OES. • Electron temperature, concentration, atomic ionization degree were calculated. • Discharge model for the growth of PEO coatings was proposed. • Temperature in the interior of alloy during PEO process was measured.

  12. Cast Aluminum Alloys for High Temperature Applications Using Nanoparticles Al2O3 and Al3-X Compounds (X = Ti, V, Zr)

    Science.gov (United States)

    Lee, Jonathan A.

    2009-01-01

    In this paper, the effect of nanoparticles Al2O3 and Al3-X compounds (X = Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their low cost, chemical stability and low diffusions rates in aluminum at high temperatures. The strengthening mechanism at high temperature for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. For Al2O3 nanoparticles, the test samples were prepared from special Al2O3 preforms, which were produced using ceramic injection molding process and then pressure infiltrated by molten aluminum. In another method, Al2O3 nanoparticles can also be homogeneously mixed with fine aluminum powder and consolidated into test samples through hot pressing and sintering. With the Al3-X nanoparticles, the test samples are produced as precipitates from in-situ reactions with molten aluminum using conventional permanent mold or die casting techniques. It is found that cast aluminum alloy using nanoparticles Al3-X is the most cost effective method to produce high strength aluminum alloys for high temperature applications in comparison to nanoparticles Al2O3. Furthermore, significant mechanical properties retention in high temperature environment could be achieved with Al3-X nanoparticles, resulting in tensile strength of nearly 3 times higher than most 300- series conventional cast aluminum alloys tested at 600 F.

  13. Structural, optical, morphological and dielectric properties of cerium oxide nanoparticles

    International Nuclear Information System (INIS)

    Cerium oxide (CeO2) nanoparticles were prepared by the precipitation method. The average crystallite size of cerium oxide nanoparticles was calculated from the X-ray diffraction (XRD) pattern and found to be 11 nm. The FT-IR spectrum clearly indicated the strong presence of cerium oxide nanoparticles. Raman spectrum confirmed the cubic nature of the cerium oxide nanoparticles. The Scanning Electron Microscopy (SEM) analysis showed that the nanoparticles agglomerated forming spherical-shaped particles. The Transmission Electron Microscopic (TEM) analysis confirmed the prepared cerium oxide nanoparticles with the particle size being found to be 16 nm. The optical absorption spectrum showed a blue shift by the cerium oxide nanoparticles due to the quantum confinement effect. The dielectric properties of cerium oxide nanoparticles were studied for different frequencies at different temperatures. The dielectric constant and the dielectric loss of the cerium oxide nanoparticles decreased with increase in frequency. The AC electrical conductivity study revealed that the conduction depended on both the frequency and the temperature. (author)

  14. Structural, optical, morphological and dielectric properties of cerium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Prabaharan, Devadoss Mangalam Durai Manoharadoss [Department of Physics, NPR College of Engineering and Technology, Natham, Dindigul, Tamil Nadu (India); Sadaiyandi, Karuppasamy [Department of Physics, Alagappa Government Arts College, Karaikudi, Sivaganga, Tamil Nadu (India); Mahendran, Manickam [Department of Physics, Thiagarajar College of Engineering, Madurai, Tamil Nadu (India); Sagadevan, Suresh, E-mail: duraiphysics2011@gmail.com [Department of Physics, AMET University (India)

    2016-03-15

    Cerium oxide (CeO{sub 2}) nanoparticles were prepared by the precipitation method. The average crystallite size of cerium oxide nanoparticles was calculated from the X-ray diffraction (XRD) pattern and found to be 11 nm. The FT-IR spectrum clearly indicated the strong presence of cerium oxide nanoparticles. Raman spectrum confirmed the cubic nature of the cerium oxide nanoparticles. The Scanning Electron Microscopy (SEM) analysis showed that the nanoparticles agglomerated forming spherical-shaped particles. The Transmission Electron Microscopic (TEM) analysis confirmed the prepared cerium oxide nanoparticles with the particle size being found to be 16 nm. The optical absorption spectrum showed a blue shift by the cerium oxide nanoparticles due to the quantum confinement effect. The dielectric properties of cerium oxide nanoparticles were studied for different frequencies at different temperatures. The dielectric constant and the dielectric loss of the cerium oxide nanoparticles decreased with increase in frequency. The AC electrical conductivity study revealed that the conduction depended on both the frequency and the temperature. (author)

  15. Investigation of different liquid media and ablation times on pulsed laser ablation synthesis of aluminum nanoparticles

    International Nuclear Information System (INIS)

    Aluminum nanoparticles were synthesized by pulsed laser ablation of Al targets in ethanol, acetone, and ethylene glycol. Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) images, Particle size distribution diagram from Laser Particle Size Analyzer (LPSA), UV-visible absorption spectra, and weight changes of targets were used for the characterization and comparison of products. The experiments demonstrated that ablation efficiency in ethylene glycol is too low, in ethanol is higher, and in acetone is highest. Comparison between ethanol and acetone clarified that acetone medium leads to finer nanoparticles (mean diameter of 30 nm) with narrower size distribution (from 10 to 100 nm). However, thin carbon layer coats some of them, which was not observed in ethanol medium. It was also revealed that higher ablation time resulted in higher ablated mass, but lower ablation rate. Finer nanoparticles, moreover, were synthesized in higher ablation times.

  16. Investigation of different liquid media and ablation times on pulsed laser ablation synthesis of aluminum nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Baladi, Arash [Materials Engineering Department, Tarbiat Modares University, Jalal Al Ahmad, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Sarraf Mamoory, Rasoul, E-mail: rsarrafm@modares.ac.ir [Materials Engineering Department, Tarbiat Modares University, Jalal Al Ahmad, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of)

    2010-10-01

    Aluminum nanoparticles were synthesized by pulsed laser ablation of Al targets in ethanol, acetone, and ethylene glycol. Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) images, Particle size distribution diagram from Laser Particle Size Analyzer (LPSA), UV-visible absorption spectra, and weight changes of targets were used for the characterization and comparison of products. The experiments demonstrated that ablation efficiency in ethylene glycol is too low, in ethanol is higher, and in acetone is highest. Comparison between ethanol and acetone clarified that acetone medium leads to finer nanoparticles (mean diameter of 30 nm) with narrower size distribution (from 10 to 100 nm). However, thin carbon layer coats some of them, which was not observed in ethanol medium. It was also revealed that higher ablation time resulted in higher ablated mass, but lower ablation rate. Finer nanoparticles, moreover, were synthesized in higher ablation times.

  17. Development and use of iron oxide nanoparticles (Part 1): Synthesis of iron oxide nanoparticles for MRI

    OpenAIRE

    2010-01-01

    Contrast agents, such as iron oxide, enhance MR images by altering the relaxation times of tissues in which the agent is present. They can also be used to label targeted molecular imaging probes. Unfortunately, no molecular imaging probe is currently available on the clinical MRI market. A promising platform for MRI contrast agent development is nanotechnology, where superparamagnetic iron oxide nanoparticles (SPIONS) are tailored for MR contrast enhancement, and/or for molecular imaging. SPI...

  18. Synthesis and oxidation of silver nanoparticles

    Science.gov (United States)

    Qi, Hua; Alexson, D. A.; Glembocki, O. J.; Prokes, S. M.

    2011-02-01

    We demonstrated a fast and easy way to synthesize Ag nanoparticles (NPs) on ZnO nanowires (NWs) and silicon substrates by an electroless (EL) plating approach. ZnO NWs used here were grown via vapor-solid (VS) mechanism at 560 °C for 30 min. The stability to oxidation of these EL-produced homogeneous Ag NPs on ZnO nanowires was investigated by surface enhanced Raman spectroscopy (SERS), showing that the attachment of thiol to the Ag surface can slow down the oxidation process, and the SERS signal remains strong for more than ten days. Furthermore, we examined the surface oxidation kinetics of the Ag NPs as a function of NPs size and size distribution by monitoring the oxygen amount in the composites using energy dispersive x-ray (EDX). Results indicate that the EL plated Ag NPs show faster oxidation rates than those produced by e-beam (EB) evaporation in air. We attribute this to the fact that the EL produced silver particles are very small, in the 20 nm range, and thus have high surface energy, thus enhancing the oxidation. These studies provide extensive information related to the Ag NP oxidation rates, which can help in extending the Ag lifetime for various applications.

  19. Toxicokinetics of zinc oxide nanoparticles in rats

    Science.gov (United States)

    Chung, H. E.; Yu, J.; Baek, M.; Lee, J. A.; Kim, M. S.; Kim, S. H.; Maeng, E. H.; Lee, J. K.; Jeong, J.; Choi, S. J.

    2013-04-01

    Zinc oxide (ZnO) nanoparticle have been extensively applied to diverse industrial fields because they possess UV light absorption, catalytic, semi-conducting, and magnetic characteristics as well as antimicrobial property. However, up to date, toxicological effects of ZnO nanoparticles in animal models have not been completely determined. Moreover, little information is available about kinetic behaviors of ZnO nanoparticles in vivo, which will be crucial to predict their potential chronic toxicity after long-term exposure. The aim of this study was, therefore, to evaluate the pharmacokinetics and toxicokinetics of ZnO nanoparticles after single-dose and repeated dose 90-day oral administration in male and female rats, respectively. The blood samples were collected following administration of three different doses (125, 250, and 500 mg/kg) and ZnO concentration was assessed by measuring zinc level with inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The result showed that the plasma ZnO concentration significantly increased in a dose-dependent manner, but decreased within 24 h after single-dose oral administration up to 500 mg/kg, without any significant difference between gender. However, when repeated dose 90-day oral toxicity study was performed, the elevated plasma concentrations did not return to normal control levels in all the cases, indicating their toxicity potential. These findings suggest that repeated oral exposure to ZnO nanoparticles up to the dose of 125 mg/kg could accumulate in the systemic circulation, thereby implying that the NOAEL values could be less than 125 mg/kg via oral intake.

  20. Toxicokinetics of zinc oxide nanoparticles in rats

    International Nuclear Information System (INIS)

    Zinc oxide (ZnO) nanoparticle have been extensively applied to diverse industrial fields because they possess UV light absorption, catalytic, semi-conducting, and magnetic characteristics as well as antimicrobial property. However, up to date, toxicological effects of ZnO nanoparticles in animal models have not been completely determined. Moreover, little information is available about kinetic behaviors of ZnO nanoparticles in vivo, which will be crucial to predict their potential chronic toxicity after long-term exposure. The aim of this study was, therefore, to evaluate the pharmacokinetics and toxicokinetics of ZnO nanoparticles after single-dose and repeated dose 90-day oral administration in male and female rats, respectively. The blood samples were collected following administration of three different doses (125, 250, and 500 mg/kg) and ZnO concentration was assessed by measuring zinc level with inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The result showed that the plasma ZnO concentration significantly increased in a dose-dependent manner, but decreased within 24 h after single-dose oral administration up to 500 mg/kg, without any significant difference between gender. However, when repeated dose 90-day oral toxicity study was performed, the elevated plasma concentrations did not return to normal control levels in all the cases, indicating their toxicity potential. These findings suggest that repeated oral exposure to ZnO nanoparticles up to the dose of 125 mg/kg could accumulate in the systemic circulation, thereby implying that the NOAEL values could be less than 125 mg/kg via oral intake.

  1. Metal oxide nanoparticles with low toxicity.

    Science.gov (United States)

    Ng, Alan Man Ching; Guo, Mu Yao; Leung, Yu Hang; Chan, Charis M N; Wong, Stella W Y; Yung, Mana M N; Ma, Angel P Y; Djurišić, Aleksandra B; Leung, Frederick C C; Leung, Kenneth M Y; Chan, Wai Kin; Lee, Hung Kay

    2015-10-01

    A number of different nanomaterials produced and incorporated into various products are rising. However, their environmental hazards are frequently unknown. Here we consider three different metal oxide compounds (SnO2, In2O3, and Al2O3), which have not been extensively studied and are expected to have low toxicity. This study aimed to comprehensively characterize the physicochemical properties of these nanomaterials and investigate their toxicity on bacteria (Escherichia coli) under UV illumination and in the dark, as well as on a marine diatom (Skeletonema costatum) under ambient illumination/dark (16-8h) cycles. The material properties responsible for their low toxicity have been identified based on comprehensive experimental characterizations and comparison to a metal oxide exhibiting significant toxicity under illumination (anatase TiO2). The metal oxide materials investigated exhibited significant difference in surface properties and interaction with the living organisms. In order for a material to exhibit significant toxicity, it needs to be able to both form a stable suspension in the culture medium and to interact with the cell walls of the test organism. Our results indicated that the observed low toxicities of the three nanomaterials could be attributed to the limited interaction between the nanoparticles and cell walls of the test organisms. This could occur either due to the lack of significant attachment between nanoparticles and cell walls, or due to their tendency to aggregate in solution. PMID:26143160

  2. A method to study the history of a double oxide film defect in liquid aluminum alloys

    Science.gov (United States)

    Raiszadeh, R.; Griffiths, W. D.

    2006-12-01

    Entrained double oxide films have been held responsible for reductions in mechanical properties in aluminum casting alloys. However, their behavior in the liquid metal, once formed, has not been studied directly. It has been proposed that the atmosphere entrapped in the double oxide film defect will continue to react with the liquid metal surrounding it, perhaps leading to its elimination as a significant defect. A silicon-nitride rod with a hole in one end was plunged into liquid aluminum to hold a known volume of air in contact with the liquid metal at a constant temperature. The change in the air volume with time was recorded by real-time X-ray radiography to determine the reaction rates of the trapped atmosphere with the liquid aluminum, creating a model for the behavior of an entrained double oxide film defect. The results from this experiment showed that first oxygen, and then nitrogen, was consumed by the aluminum alloy, to form aluminum oxide and aluminum nitride, respectively. The effect of adding different elements to the liquid aluminum and the effect of different hydrogen contents were also studied.

  3. Heteroaggregation of Cerium Oxide Nanoparticles and Nanoparticles of Pyrolyzed Biomass.

    Science.gov (United States)

    Yi, Peng; Pignatello, Joseph J; Uchimiya, Minori; White, Jason C

    2015-11-17

    Heteroaggregation with indigenous particles is critical to the environmental mobility of engineered nanomaterials (ENM). We studied heteroaggregation of ceria nanoparticles (n-CeO2), as a model for metal oxide ENM, with nanoparticles of pyrogenic carbonaceous material (n-PCM) derived from pecan shell biochar, a model for natural chars and human-made chars used in soil remediation and agriculture. The TEM and STEM images of n-PCM identify both hard and soft particles, both C-rich and C,O,Ca-containing particles (with CaCO3 crystals), both amorphous and "onion-skin" C-rich particles, and traces of nanotubes. Heteroaggregation was evaluated at constant n-CeO2, variable n-PCM concentration by monitoring hydrodynamic diameter by dynamic light scattering and ζ-potential under conditions where n-PCM is "invisible". At pH 5.3, where n-CeO2 and n-PCM are positively and negatively charged, respectively, and each stable to homoaggregation, heteroaggregation is favorable and occurs by a charge neutralization-charge reversal mechanism (CNCR): in this mechanism, primary heteroaggregates that form in the initial stage are stable at low or high n-PCM concentration due to electrostatic repulsion, but unstable at intermediate n-PCM concentration, leading to secondary heteroaggregation. The greatest instability coincides with full charge neutralization. At pH 7.1, where n-CeO2 is neutral and unstable alone, and n-PCM is negative and stable alone, heteroaggregation occurs by a charge-accumulation, core-shell stabilization (CACS) mechanism: n-PCM binds to and forms a negatively charged shell on the neutral surface of the nascent n-CeO2 core, stabilizing the core-shell heteraggregate at a size that decreases with n-PCM concentration. The CNCR and CACS mechanisms give fundamental insight into heteroaggregation between oppositely charged, and between neutral and charged nanoparticles. PMID:26461459

  4. The Effect of Metal Oxide on Nanoparticles from Thermite Reactions

    Science.gov (United States)

    Moore, Lewis Ryan

    2006-01-01

    The purpose of this research was to determine how metal oxide used in a thermite reaction can impact the production of nanoparticles. The results showed the presence of nanoparticles (less than 1 micron in diameter) of at least one type produced by each metal oxide. The typical particles were metallic spheres, which ranged from 300 nanometers in…

  5. Nanothermometry using optically trapped erbium oxide nanoparticle

    Science.gov (United States)

    Baral, Susil; Johnson, Samuel C.; Alaulamie, Arwa A.; Richardson, Hugh H.

    2016-04-01

    A new optical probe technique using a laser-trapped erbium oxide nanoparticle (size ~150 nm) is introduced that can measure absolute temperature with a spatial resolution on the size of the trapped nanoparticle. This technique (scanning optical probe thermometry) is used to collect a thermal image of a gold nanodot prepared with hole-mask colloidal lithography. A convolution analysis of the thermal profile shows that the point spread function of our measurement is a Gaussian with a FWHM of 165 nm. We attribute the width of this function to clustering of Er2O3 nanoparticles in solution. The scanning optical probe thermometer is used to measure the temperature where vapor nucleation occurs in degassed water (555 K), confirming that a nanoscale object heated in water will superheat the surrounding water to the spinodal decomposition temperature. Subsequently, the temperature inside the vapor bubble rises to the melting point of the gold nanostructure (~1300) where a temperature plateau is observed. The rise in temperature is attributed to inhibition of thermal transfer to the surrounding liquid by the thermal insulating vapor cocoon.

  6. Passivation effects of atomic-layer-deposited aluminum oxide

    Directory of Open Access Journals (Sweden)

    Kotipalli R.

    2013-09-01

    Full Text Available Atomic-layer-deposited (ALD aluminum oxide (Al2O3 has recently demonstrated an excellent surface passivation for both n- and p-type c-Si solar cells thanks to the presence of high negative fixed charges (Qf ~ 1012−1013 cm-2 in combination with a low density of interface states (Dit. This paper investigates the passivation quality of thin (15 nm Al2O3 films deposited by two different techniques: plasma-enhanced atomic layer deposition (PE-ALD and Thermal atomic layer deposition (T-ALD. Other dielectric materials taken into account for comparison include: thermally-grown silicon dioxide (SiO2 (20 nm, SiO2 (20 nm deposited by plasma-enhanced chemical vapour deposition (PECVD and hydrogenated amorphous silicon nitride (a-SiNx:H (20 nm also deposited by PECVD. With the above-mentioned dielectric layers, Metal Insulator Semiconductor (MIS capacitors were fabricated for Qf and Dit extraction through Capacitance-Voltage-Conductance (C-V-G measurements. In addition, lifetime measurements were carried out to evaluate the effective surface recombination velocity (SRV. The influence of extracted C-V-G parameters (Qf,Dit on the injection dependent lifetime measurements τ(Δn, and the dominant passivation mechanism involved have been discussed. Furthermore we have also studied the influence of the SiO2 interfacial layer thickness between the Al2O3 and silicon surface on the field-effect passivation mechanism. It is shown that the field effect passivation in accumulation mode is more predominant when compared to surface defect passivation.

  7. Antibacterial Activity of Polymer Coated Cerium Oxide Nanoparticles

    OpenAIRE

    Shah, Vishal; Shah, Shreya; Shah, Hirsh; Rispoli, Fred J.; McDonnell, Kevin T.; Workeneh, Selam; Karakoti, Ajay; Kumar, Amit; Seal, Sudipta

    2012-01-01

    Cerium oxide nanoparticles have found numerous applications in the biomedical industry due to their strong antioxidant properties. In the current study, we report the influence of nine different physical and chemical parameters: pH, aeration and, concentrations of MgSO4, CaCl2, KCl, natural organic matter, fructose, nanoparticles and Escherichia coli, on the antibacterial activity of dextran coated cerium oxide nanoparticles. A least-squares quadratic regression model was developed to underst...

  8. Controlled Variable Oxidative Doping of Individual Organometallic Nanoparticles.

    Science.gov (United States)

    Feng, Ann; Cheng, Wei; Holter, Jennifer; Young, Neil; Compton, Richard G

    2016-05-10

    The charging and controlled oxidative doping of single organometallic ferrocene nanoparticles is reported in aqueous sodium tetrafluoroborate using the nano-impacts method. It is shown that ferrocene nanoparticles of approximately 105 nm diameter are essentially quantitatively oxidatively doped with the uptake of one tetrafluoroborate anion per ferrocene molecule at suitably high overpotentials. By using lower potentials, it is possible to achieve low doping levels of single nanoparticles in a controlled manner. PMID:27038252

  9. Enzymatic biosensors based on the use of metal oxide nanoparticles

    International Nuclear Information System (INIS)

    Over the past decades, various techniques have been developed to obtain materials at a nanoscale level to design biosensors with high sensitivity, selectivity and efficiency. Metal oxide nanoparticles (MONPs) are of particular interests and have received much attention because of their unique physical, chemical and catalytic properties. This review summarizes the progress made in enzymatic biosensors based on the use of MONPs. Synthetic methods, strategies for immobilization, and the functions of MONPs in enzymatic biosensing systems are reviewed and discussed. The article is subdivided into sections on enzymatic biosensors based on (a) zinc oxide nanoparticles, (b) titanium oxide nanoparticles, (c) iron oxide nanoparticles, and (d) other metal oxide nanoparticles. While substantial advances have been made in MONPs-based enzymatic biosensors, their applications to real samples still lie ahead because issues such as reproducibility and sensor stability have to be solved. (author)

  10. Interaction of ester functional groups with aluminum oxide surfaces studied using infrared reflection absorption spectroscopy.

    Science.gov (United States)

    van den Brand, J; Blajiev, O; Beentjes, P C J; Terryn, H; de Wit, J H W

    2004-07-20

    The bonding of two types of ester group-containing molecules with a set of different oxide layers on aluminum has been investigated using infrared reflection absorption spectroscopy. The different oxide layers were made by giving typical surface treatments to the aluminum substrate. The purpose of the investigation was to find out what type of ester-oxide bond is formed and whether this is influenced by changes in the composition and chemistry of the oxide. The extent by which these bonded ester molecules resisted disbondment in water or substitution by molecules capable of chemisorption was also investigated. The ester groups were found to show hydrogen bonding with hydroxyls on the oxide surfaces through their carbonyl oxygens. For all oxides, the ester groups showed the same nu(C = O) carbonyl stretching vibration after adsorption, indicating very similar bonding occurs. However, the oxides showed differences in the amount of molecules bonded to the oxide surface, and a clear relation was observed with the hydroxyl concentration present on the oxide surface, which was determined from XPS measurements. The two compounds showed differences in the free to bonded nu(C = O) infrared peak shift, indicating differences in bonding strength with the oxide surface between the two types of molecules. The bonding of the ester groups with the oxide surfaces was found to be not stable in the presence of water and also not in the presence of a compound capable of chemisorption with the aluminum oxide surface. PMID:15248718

  11. Remarkable enhancement of upconversion luminescence on 2-D anodic aluminum oxide photonic crystals.

    Science.gov (United States)

    Wang, He; Yin, Ze; Xu, Wen; Zhou, Donglei; Cui, Shaobo; Chen, Xu; Cui, Haining; Song, Hongwei

    2016-05-21

    Lanthanide-doped upconversion nanoparticles (UCNPs) are attracting extensive attention due to their unique physical properties and great application potential. However, the lower luminescence quantum yield/strength is still an obstacle for real application. Local field modulation is a promising method to highly enhance the upconversion luminescence (UCL) of the UCNPs. In this work, a novel kind of two-dimensional photonic crystal (2D-PC), anodic aluminum oxides (AAOs), was explored to improve the UCL of NaYF4:Yb(3+),Er(3+) nanoplates (NPs). An optimum enhancement factor (EF) of 65-fold was obtained for the overall intensity of Er(3+) under 980 nm excitation, and 130-fold for the red emission. Systematic studies indicate that UCL enhancement mainly originates from the enlargement of the excitation field by scattering and reflection of AAO PCs. It should also be highlighted that the modulation of 2D-PC on the UCL of NaYF4:Yb(3+),Er(3+) NPs demonstrates weak size-dependent and thickness-dependent behavior, which is well consistent with the stimulated electromagnetic field distribution by the finite difference time domain (FDTD) method. PMID:27139324

  12. Improvement of plasmonic enhancement of quantum dot emission via an intermediate silicon-aluminum oxide interface

    International Nuclear Information System (INIS)

    We studied the emission of quantum dots in the presence of plasmon-metal oxide substrates, which consist of arrays of metallic nanorods embedded in amorphous silicon coated with a nanometer-thin layer of aluminum oxide on the top. We showed that the combined effects of plasmons and the silicon-aluminum oxide interface can lead to significant enhancement of the quantum efficiency of quantum dots. Our results show that such an interface can significantly enhance plasmonic effects of the nanorods via quantum dot-induced exciton-plasmon coupling, leading to partial polarization of the quantum dots' emission

  13. Niobium-aluminum base alloys having improved, high temperature oxidation resistance

    Science.gov (United States)

    Hebsur, Mohan G. (Inventor); Stephens, Joseph R. (Inventor)

    1991-01-01

    A niobium-aluminum base alloy having improved oxidation resistance at high temperatures and consisting essentially of 48%-52% niobium, 36%-42% aluminum, 4%-10% chromium, 0%-2%, more preferably 1%-2%, silicon and/or tungsten with tungsten being preferred, and 0.1%-2.0% of a rare earth selected from the group consisting of yttrium, ytterbium and erbium. Parabolic oxidation rates, k.sub.p, at 1200.degree. C. range from about 0.006 to 0.032 (mg/cm.sup.2).sup.2 /hr. The new alloys also exhibit excellent cyclic oxidation resistance.

  14. Optical Anisotropy and Porosity of Anodic Aluminum Oxide Characterized by Spectroscopic Ellipsometry

    NARCIS (Netherlands)

    Kooij, E. Stefan; Wormeester, Herbert; Galca, Aurelian C.; Poelsema, Bene

    2003-01-01

    Anodic oxidation of aluminum results in a mesoporous oxide film. The thin-film geometry of our samples enables straightforward optical modeling of ellipsometry spectra of fully anodized films, using only three physically relevant parameters. The system of randomly distributed, but aligned cylindrica

  15. Microbial-mediated method for metal oxide nanoparticle formation

    Energy Technology Data Exchange (ETDEWEB)

    Rondinone, Adam J.; Moon, Ji Won; Love, Lonnie J.; Yeary, Lucas W.; Phelps, Tommy J.

    2015-09-08

    The invention is directed to a method for producing metal oxide nanoparticles, the method comprising: (i) subjecting a combination of reaction components to conditions conducive to microbial-mediated formation of metal oxide nanoparticles, wherein said combination of reaction components comprise: metal-reducing microbes, a culture medium suitable for sustaining said metal-reducing microbes, an effective concentration of one or more surfactants, a reducible metal oxide component containing one or more reducible metal species, and one or more electron donors that provide donatable electrons to said metal-reducing microbes during consumption of the electron donor by said metal-reducing microbes; and (ii) isolating said metal oxide nanoparticles, which contain a reduced form of said reducible metal oxide component. The invention is also directed to metal oxide nanoparticle compositions produced by the inventive method.

  16. In situ oxidation study of supported Rh and Pd nanoparticles

    OpenAIRE

    Nolte, Philipp

    2009-01-01

    The targeted development of catalysts requires a detailed understanding of the atomic structure of nanoparticles during chemical reactions. Within this thesis project the oxidation properties of rhodium and palladium nanoparticles with diameters ranging from 4 nm to 24 nm on magnesium oxide and aluminium oxide were investigated. Much of the cognition about catalysts on an atomic scale acquired hitherto stems from studies of single crystal surfaces at pressures near high vacuum. In applica...

  17. Titanium oxide nanoparticle production using high power pulsed plasmas

    OpenAIRE

    Gunnarsson, Rickard

    2016-01-01

    This thesis covers fundamental aspects of process control when growing titanium oxide nanoparticles in a reactive sputtering process. It covers the influence of oxygen containing gas on the oxidation state of the cathode from which the growth material is ejected, as well as its influence on the particles oxidation state and their nucleation. It was found that a low degree of reactive gases was necessary for nanoparticles of titanium to nucleate. When the oxygen gas was slightly increased, the...

  18. Anticancer activity of Ficus religiosa engineered copper oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sankar, Renu; Maheswari, Ramasamy; Karthik, Selvaraju [Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu (India); Shivashangari, Kanchi Subramanian, E-mail: shivashangari@gmail.com [Regional Forensic Science Laboratory, Tiruchirapalli, Tamilnadu (India); Ravikumar, Vilwanathan, E-mail: ravikumarbdu@gmail.com [Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu (India)

    2014-11-01

    The design, synthesis, characterization and application of biologically synthesized nanomaterials have become a vital branch of nanotechnology. There is a budding need to develop a method for environmentally benign metal nanoparticle synthesis, that do not use toxic chemicals in the synthesis protocols to avoid adverse effects in medical applications. Here, it is a report on an eco-friendly process for rapid synthesis of copper oxide nanoparticles using Ficus religiosa leaf extract as reducing and protecting agent. The synthesized copper oxide nanoparticles were confirmed by UV–vis spectrophotometer, absorbance peaks at 285 nm. The copper oxide nanoparticles were analyzed with field emission-scanning electron microscope (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS) and X-ray diffraction (XRD) spectrum. The FE-SEM and DLS analyses exposed that copper oxide nanoparticles are spherical in shape with an average particle size of 577 nm. FT-IR spectral analysis elucidates the occurrence of biomolecules required for the reduction of copper oxide ions. Zeta potential studies showed that the surface charge of the formed nanoparticles was highly negative. The XRD pattern revealed that synthesized nanoparticles are crystalline in nature. Further, biological activities of the synthesized nanoparticles were confirmed based on its stable anti-cancer effects. The apoptotic effect of copper oxide nanoparticles is mediated by the generation of reactive oxygen species (ROS) involving the disruption of mitochondrial membrane potential (Δψm) in A549 cells. The observed characteristics and results obtained in our in vitro assays suggest that the copper nanoparticles might be a potential anticancer agent. - Highlights: • Biogenic synthesis of copper oxide nanoparticles by leaf extract of Ficus religiosa • Characterized via UV–vis, FT-IR, DLS, FE-SEM with EDAX and XRD • Protein may act as an encapsulating, reducing and stabilizing

  19. Anticancer activity of Ficus religiosa engineered copper oxide nanoparticles

    International Nuclear Information System (INIS)

    The design, synthesis, characterization and application of biologically synthesized nanomaterials have become a vital branch of nanotechnology. There is a budding need to develop a method for environmentally benign metal nanoparticle synthesis, that do not use toxic chemicals in the synthesis protocols to avoid adverse effects in medical applications. Here, it is a report on an eco-friendly process for rapid synthesis of copper oxide nanoparticles using Ficus religiosa leaf extract as reducing and protecting agent. The synthesized copper oxide nanoparticles were confirmed by UV–vis spectrophotometer, absorbance peaks at 285 nm. The copper oxide nanoparticles were analyzed with field emission-scanning electron microscope (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS) and X-ray diffraction (XRD) spectrum. The FE-SEM and DLS analyses exposed that copper oxide nanoparticles are spherical in shape with an average particle size of 577 nm. FT-IR spectral analysis elucidates the occurrence of biomolecules required for the reduction of copper oxide ions. Zeta potential studies showed that the surface charge of the formed nanoparticles was highly negative. The XRD pattern revealed that synthesized nanoparticles are crystalline in nature. Further, biological activities of the synthesized nanoparticles were confirmed based on its stable anti-cancer effects. The apoptotic effect of copper oxide nanoparticles is mediated by the generation of reactive oxygen species (ROS) involving the disruption of mitochondrial membrane potential (Δψm) in A549 cells. The observed characteristics and results obtained in our in vitro assays suggest that the copper nanoparticles might be a potential anticancer agent. - Highlights: • Biogenic synthesis of copper oxide nanoparticles by leaf extract of Ficus religiosa • Characterized via UV–vis, FT-IR, DLS, FE-SEM with EDAX and XRD • Protein may act as an encapsulating, reducing and stabilizing

  20. Fungus mediated synthesis of biomedically important cerium oxide nanoparticles

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • First time biological synthesis of cerium oxide oxide nanoparticles using fungus Humicola sp. • Complete characterization of cerium oxide nanoparticles. • Biosynthesis of naturally protein capped, luminescent and water dispersible CeO2 nanoparticles. • Biosynthesized CeO2 nanoparticles can be used for many biomedical applications. - Abstract: Nanomaterials can be synthesized by chemical, physical and the more recently discovered biological routes. The biological routes are advantageous over the chemical and physical ones as unlike these, the biological synthesis protocols occur at ambient conditions, are cheap, non-toxic and eco-friendly. Although purely biological and bioinspired methods for the synthesis of nanomaterials are environmentally benign and energy conserving processes, their true potential has not been explored yet and attempts are being made to extend the formation of technologically important nanoparticles using microorganisms like fungi. Though there have been reports on the biosynthesis of oxide nanoparticles by our group in the past, no attempts have been made to employ fungi for the synthesis of nanoparticles of rare earth metals or lanthanides. Here we report for the first time, the bio-inspired synthesis of biomedically important cerium oxide (CeO2) nanoparticles using the thermophilic fungus Humicola sp. The fungus Humicola sp. when exposed to aqueous solutions of oxide precursor cerium (III) nitrate hexahydrate (CeN3O9·6H2O) results in the extracellular formation of CeO2 nanoparticles containing Ce (III) and Ce (IV) mixed oxidation states, confirmed by X-ray Photoemission Spectroscopy (XPS). The formed nanoparticles are naturally capped by proteins secreted by the fungus and thus do not agglomerate, are highly stable, water dispersible and are highly fluorescent as well. The biosynthesized nanoparticles were characterized by UV–vis spectroscopy, Photoluminescence spectroscopy (PL), Transmission

  1. Murine pulmonary responses after sub-chronic exposure to aluminum oxide-based nanowhiskers

    OpenAIRE

    Adamcakova-Dodd Andrea; Stebounova Larissa V; O’Shaughnessy Patrick T; Kim Jong; Grassian Vicki H; Thorne Peter S

    2012-01-01

    Abstract Background Aluminum oxide-based nanowhiskers (AO nanowhiskers) have been used in manufacturing processes as catalyst supports, flame retardants, adsorbents, or in ceramic, metal and plastic composite materials. They are classified as high aspect ratio nanomaterials. Our aim was to assess in vivo toxicity of inhaled AO nanowhisker aerosols. Methods Primary dimensions of AO nanowhiskers specified by manufacturer were 2–4 nm x 2800 nm. The aluminum content found in this nanomaterial was...

  2. Electrophoretic deposition of PTFE particles on porous anodic aluminum oxide film and its tribological properties

    International Nuclear Information System (INIS)

    Polytetrafluoroethylene (PTFE) composite film was successfully fabricated by depositing PTFE particles into porous anodic aluminum oxide film using electrophoretic deposition (EPD) process. Firstly, porous anodic aluminum oxide film was synthesized by anodic oxidation process in sulphuric acid electrolyte. Then, PTFE particles in suspension were directionally deposited into the porous substrate. Finally, a heat treatment at 300 °C for 1 h was utilized to enhance PTFE particles adhesion to the substrate. The influence of anodic oxidation parameters on the morphology and micro-hardness of the porous anodic aluminum oxide film was studied and the PTFE particles deposited into the pores were authenticated using energy-dispersive spectrometer (EDS) and scanning electron microscopy (SEM). Tribological properties of the PTFE composite film were investigated under dry sliding. The experimental results showed that the composite film exhibit remarkable low friction. The composite film had friction coefficient of 0.20 which deposited in 15% PTFE emulsion at temperature of 15 °C and current density of 3 A/dm2 for 35 min. In addition, a control specimen of porous anodic aluminum oxide film and the PTFE composite film were carried out under the same test condition, friction coefficient of the PTFE composite film was reduced by 60% comparing with the control specimen at 380 MPa and 100 mm/s. The lubricating mechanism was that PTFE particles embedded in porous anodic aluminum oxide film smeared a transfer film on the sliding path and the micro-pores could support the supplement of solid lubricant during the sliding, which prolonged the lubrication life of the aluminum alloys.

  3. Electrophoretic deposition of PTFE particles on porous anodic aluminum oxide film and its tribological properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dongya; Dong, Guangneng, E-mail: donggn@mail.xjtu.edu.cn; Chen, Yinjuan; Zeng, Qunfeng

    2014-01-30

    Polytetrafluoroethylene (PTFE) composite film was successfully fabricated by depositing PTFE particles into porous anodic aluminum oxide film using electrophoretic deposition (EPD) process. Firstly, porous anodic aluminum oxide film was synthesized by anodic oxidation process in sulphuric acid electrolyte. Then, PTFE particles in suspension were directionally deposited into the porous substrate. Finally, a heat treatment at 300 °C for 1 h was utilized to enhance PTFE particles adhesion to the substrate. The influence of anodic oxidation parameters on the morphology and micro-hardness of the porous anodic aluminum oxide film was studied and the PTFE particles deposited into the pores were authenticated using energy-dispersive spectrometer (EDS) and scanning electron microscopy (SEM). Tribological properties of the PTFE composite film were investigated under dry sliding. The experimental results showed that the composite film exhibit remarkable low friction. The composite film had friction coefficient of 0.20 which deposited in 15% PTFE emulsion at temperature of 15 °C and current density of 3 A/dm{sup 2} for 35 min. In addition, a control specimen of porous anodic aluminum oxide film and the PTFE composite film were carried out under the same test condition, friction coefficient of the PTFE composite film was reduced by 60% comparing with the control specimen at 380 MPa and 100 mm/s. The lubricating mechanism was that PTFE particles embedded in porous anodic aluminum oxide film smeared a transfer film on the sliding path and the micro-pores could support the supplement of solid lubricant during the sliding, which prolonged the lubrication life of the aluminum alloys.

  4. Electrophoretic deposition of PTFE particles on porous anodic aluminum oxide film and its tribological properties

    Science.gov (United States)

    Zhang, Dongya; Dong, Guangneng; Chen, Yinjuan; Zeng, Qunfeng

    2014-01-01

    Polytetrafluoroethylene (PTFE) composite film was successfully fabricated by depositing PTFE particles into porous anodic aluminum oxide film using electrophoretic deposition (EPD) process. Firstly, porous anodic aluminum oxide film was synthesized by anodic oxidation process in sulphuric acid electrolyte. Then, PTFE particles in suspension were directionally deposited into the porous substrate. Finally, a heat treatment at 300 °C for 1 h was utilized to enhance PTFE particles adhesion to the substrate. The influence of anodic oxidation parameters on the morphology and micro-hardness of the porous anodic aluminum oxide film was studied and the PTFE particles deposited into the pores were authenticated using energy-dispersive spectrometer (EDS) and scanning electron microscopy (SEM). Tribological properties of the PTFE composite film were investigated under dry sliding. The experimental results showed that the composite film exhibit remarkable low friction. The composite film had friction coefficient of 0.20 which deposited in 15% PTFE emulsion at temperature of 15 °C and current density of 3 A/dm2 for 35 min. In addition, a control specimen of porous anodic aluminum oxide film and the PTFE composite film were carried out under the same test condition, friction coefficient of the PTFE composite film was reduced by 60% comparing with the control specimen at 380 MPa and 100 mm/s. The lubricating mechanism was that PTFE particles embedded in porous anodic aluminum oxide film smeared a transfer film on the sliding path and the micro-pores could support the supplement of solid lubricant during the sliding, which prolonged the lubrication life of the aluminum alloys.

  5. Iron oxide nanoparticle enhancement of radiation cytotoxicity

    Science.gov (United States)

    Mazur, Courtney M.; Tate, Jennifer A.; Strawbridge, Rendall R.; Gladstone, David J.; Hoopes, P. Jack

    2013-02-01

    Iron oxide nanoparticles (IONPs) have been investigated as a promising means for inducing tumor cell-specific hyperthermia. Although the ability to generate and use nanoparticles that are biocompatible, tumor specific, and have the ability to produce adequate cytotoxic heat is very promising, significant preclinical and clinical development will be required for clinical efficacy. At this time it appears using IONP-induced hyperthermia as an adjunct to conventional cancer therapeutics, rather than as an independent treatment, will provide the initial IONP clinical treatment. Due to their high-Z characteristics, another option is to use intracellular IONPs to enhance radiation therapy without excitation with AMF (production of heat). To test this concept IONPs were added to cell culture media at a concentration of 0.2 mg Fe/mL and incubated with murine breast adenocarcinoma (MTG-B) cells for either 48 or 72 hours. Extracellular iron was then removed and all cells were irradiated at 4 Gy. Although samples incubated with IONPs for 48 hrs did not demonstrate enhanced post-irradiation cytotoxicity as compared to the non-IONP-containing cells, cells incubated with IONPs for 72 hours, which contained 40% more Fe than 48 hr incubated cells, showed a 25% decrease in clonogenic survival compared to their non-IONP-containing counterparts. These results suggest that a critical concentration of intracellular IONPs is necessary for enhancing radiation cytotoxicity.

  6. Nanoparticles, lung injury, and the role of oxidant stress.

    Science.gov (United States)

    Madl, Amy K; Plummer, Laurel E; Carosino, Christopher; Pinkerton, Kent E

    2014-01-01

    The emergence of engineered nanoscale materials has provided significant advancements in electronic, biomedical, and material science applications. Both engineered nanoparticles and nanoparticles derived from combustion or incidental processes exhibit a range of physical and chemical properties that induce inflammation and oxidative stress in biological systems. Oxidative stress reflects the imbalance between the generation of reactive oxygen species and the biochemical mechanisms to detoxify and repair the damage resulting from reactive intermediates. This review examines current research on incidental and engineered nanoparticles in terms of their health effects on lungs and the mechanisms by which oxidative stress via physicochemical characteristics influences toxicity or biocompatibility. Although oxidative stress has generally been thought of as an adverse biological outcome, this review also briefly discusses some of the potential emerging technologies to use nanoparticle-induced oxidative stress to treat disease in a site-specific fashion. PMID:24215442

  7. NEXAFS Study of Air Oxidation for Mg Nanoparticle Thin Film

    Science.gov (United States)

    Ogawa, S.; Murakami, S.; Shirai, K.; Nakanishi, K.; Ohta, T.; Yagi, S.

    2013-03-01

    The air oxidation reaction of Mg nanoparticle thin film has been investigated by Mg K-edge NEXAFS technique. It is revealed that MgO is formed on the Mg nanoparticle surfaces at the early stage of the air oxidation for Mg nanoparticle thin film. The simulation of NEXAFS spectrum using standard spectra indicates the existence of complex magnesium carbonates (x(MgCO3).yMg(OH2).z(H2O)) in addition to MgO at the early stage of the air oxidation.

  8. Structural features of anodic oxide films formed on aluminum substrate coated with self-assembled microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Asoh, Hidetaka [Department of Applied Chemistry, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 (Japan)], E-mail: asoh@cc.kogakuin.ac.jp; Uchibori, Kota; Ono, Sachiko [Department of Applied Chemistry, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 (Japan)

    2009-07-15

    The structural features of anodic oxide films formed on an aluminum substrate coated with self-assembled microspheres were investigated by scanning electron microscopy and atomic force microscopy. In the first anodization in neutral solution, the growth of a barrier-type film was partially suppressed in the contact area between the spheres and the underlying aluminum substrate, resulting in the formation of ordered dimple arrays in an anodic oxide film. After the subsequent second anodization in acid solution at a voltage lower than that of the first anodization, nanopores were generated only within each dimple. The nanoporous region could be removed selectively by post-chemical etching using the difference in structural dimensions between the porous region and the surrounding barrier region. The mechanism of anodic oxide growth on the aluminum substrate coated with microspheres through multistep anodization is discussed.

  9. Dextran-modified iron oxide nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Jií; Hradil

    2007-01-01

    [1]Anger,S.,Caldwell,K.,Mehnert,W.,& Muller,R.(1999).Coating of nanoparticles:Analysis of adsorption using sedimentation field-flow fractionation(SdFFF).Proceedings of International Symposium of Controlled Release of Bioactivated Materials,26,599-600.[2]Bonnemain,B.(1998).Superparamagnetic agents in magnetic resonance imaging:Physicochemical characteristics and clinical applications-A review.Journal of Drug Targeting,6(3),167-174.[3]Bootz,A.,Vogel,V.,Schubert,D.,& Kreuter,J.(2004).Comparison of scanning electron microscopy,dynamic light scattering and analytical ultracentrifugation for the sizing of poly(butyl cyanoacrylate) nanoparticles.European Journal of Pharmaceutics and Biopharmaceutics,57(2),369-375.[4]Browarzik,D.(1997).Continuous kinetics of dextran degradation.Journal of Macromolecular Science Pure and Applied Chemistry,34(3),397-404.[5]Cabasso,I.,& Yuan,Y.(1996).Nanoparticles in polymer and polymer dendrimers.In J.Fendler & I.Dekany (Eds.),NATO ASI Series.Part 18Nanoparticles in Solids and Solutions (pp.131-153).[6]Chastellain,M.,Petri,A.,& Hofmann,H.(2004).Particle size investigation of a multistep synthesis of PVA coated superparamagnetic nanoparticles.Journal of Colloid Interface Science,278(2),353-360.[7]Chmela,E.,Tijssen,R.,Blom,M.T.,Gardeniers,H.J.G.E.,& van den Berg,A.(2002).A chip system for size separation of macromolecules and particles by hydrodynamic chromatography.Analytical Chemistry,74(14),3470-3475.[8]Confer,D.R.,& Logan,B.E.(1997).Molecular weight distribution of hydrolysis product during the biodegradation of model macromolecules in suspended and biofilm cultures.Ⅱ:Dextran and dextrin.Water Research,31(9),2137-2145.[9]Griffiths,C.H.,O'Horo,M.P.,& Smith,T.W.(1979).The structure,magnetic characterization and oxidation of colloidal iron dispersions.Journal of Applied Physics,50(11),7108-7115.[10]Gupta,A.K.,& Gupta,M.(2005).Synthesis and surface engineering of iron oxide nanoparticles for biomedical applications.Biomaterials,26

  10. Radiation-induced synthesis of gold, iron-oxide composite nanoparticles

    International Nuclear Information System (INIS)

    Composite nanoparticles consisting of magnetic iron oxide nanoparticles and gold nanoparticles were synthesized using gamma-rays or electron beam. Ionizing irradiation induces the generation of reducing species inside the aqueous solution, and gold ions are reduced to form metallic Au nanoparticles. The size of Au nanoparticles depended on the dose rate and the concentration of support iron oxide. The gold nanoparticles on iron oxide nanoparticles selectively adsorb biomolecules via Au-S bonding. By using magnetic property of the support iron oxide nanoparticles, the composite nanoparticles are expected as a new type of magnetic nanocarrier for biomedical applications. (author)

  11. Zinc Oxide Nanoparticles for Revolutionizing Agriculture: Synthesis and Applications

    Directory of Open Access Journals (Sweden)

    Sidra Sabir

    2014-01-01

    Full Text Available Nanotechnology is the most innovative field of 21st century. Extensive research is going on for commercializing nanoproducts throughout the world. Due to their unique properties, nanoparticles have gained considerable importance compared to bulk counterparts. Among other metal nanoparticles, zinc oxide nanoparticles are very much important due to their utilization in gas sensors, biosensors, cosmetics, drug-delivery systems, and so forth. Zinc oxide nanoparticles (ZnO NPs also have remarkable optical, physical, and antimicrobial properties and therefore have great potential to enhance agriculture. As far as method of formation is concerned, ZnO NPs can be synthesized by several chemical methods such as precipitation method, vapor transport method, and hydrothermal process. The biogenic synthesis of ZnO NPs by using different plant extracts is also common nowadays. This green synthesis is quite safe and ecofriendly compared to chemical synthesis. This paper elaborates the synthesis, properties, and applications of zinc oxide nanoparticles.

  12. Effect of Silver Coating on Barium Titanium Oxide Nanoparticle Toxicity

    OpenAIRE

    Obregon, Isidro D.; Betts-Obregon, Brandi S.; Yust, Brian; Pedraza, Francisco; Ortiz, Alexandra; Sardar, Dhiraj; Tsin, Andrew T.

    2013-01-01

    Nanoparticles are presently being studied for optical and biomedical applications such as medical imaging and drug delivery. Nanoparticles impact the cellular environment due to many variables such as size, shape, and composition. How these factors affect cell viability is not fully understood. The purpose of this study is to test the toxicity effects of silver coating (Ag@) Barium Titanium Oxide (BaTiO3) nanoparticles on Rhesus Monkey Retinal Endothelial cells (RhREC’s) in culture. The addit...

  13. A Conductometric Indium Oxide Semiconducting Nanoparticle Enzymatic Biosensor Array

    OpenAIRE

    Tianhong Cui; Janet Ondrake; Dongjin Lee

    2011-01-01

    We report a conductometric nanoparticle biosensor array to address the significant variation of electrical property in nanomaterial biosensors due to the random network nature of nanoparticle thin-film. Indium oxide and silica nanoparticles (SNP) are assembled selectively on the multi-site channel area of the resistors using layer-by-layer self-assembly. To demonstrate enzymatic biosensing capability, glucose oxidase is immobilized on the SNP layer for glucose detection. The packaged sensor c...

  14. Atmospheric pressure plasma enhanced chemical vapor deposition of zinc oxide and aluminum zinc oxide

    International Nuclear Information System (INIS)

    Zinc oxide (ZnO) and aluminum-doped zinc oxide (AZO) thin films were deposited via atmospheric pressure plasma enhanced chemical vapor deposition. A second-generation precursor, bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(N,N′-diethylethylenediamine) zinc, exhibited significant vapor pressure and good stability at one atmosphere where a vaporization temperature of 110 °C gave flux ∼ 7 μmol/min. Auger electron spectroscopy confirmed that addition of H2O to the carrier gas stream mitigated F contamination giving nearly 1:1 metal:oxide stoichiometries for both ZnO and AZO with little precursor-derived C contamination. ZnO and AZO thin film resistivities ranged from 14 to 28 Ω·cm for the former and 1.1 to 2.7 Ω·cm for the latter. - Highlights: • A second generation precursor was utilized for atmospheric pressure film growth. • Addition of water vapor to the carrier gas stream led to a marked reduction of ZnF2. • Carbonaceous contamination from the precursor was minimal

  15. Atmospheric pressure plasma enhanced chemical vapor deposition of zinc oxide and aluminum zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Kyle W. [Center for Nanoscale Science and Engineering, North Dakota State University, Fargo, ND (United States); Department of Mechanical Engineering, North Dakota State University, Fargo, ND (United States); Guruvenket, Srinivasan; Sailer, Robert A. [Center for Nanoscale Science and Engineering, North Dakota State University, Fargo, ND (United States); Ahrenkiel, S. Phillip [Department of Nanoscience and Nanoengineering, South Dakota School of Mines and Technology, Rapid City, SD (United States); Schulz, Douglas L., E-mail: SBRconsulting@hotmail.com [Center for Nanoscale Science and Engineering, North Dakota State University, Fargo, ND (United States); Department of Mechanical Engineering, North Dakota State University, Fargo, ND (United States)

    2013-12-02

    Zinc oxide (ZnO) and aluminum-doped zinc oxide (AZO) thin films were deposited via atmospheric pressure plasma enhanced chemical vapor deposition. A second-generation precursor, bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(N,N′-diethylethylenediamine) zinc, exhibited significant vapor pressure and good stability at one atmosphere where a vaporization temperature of 110 °C gave flux ∼ 7 μmol/min. Auger electron spectroscopy confirmed that addition of H{sub 2}O to the carrier gas stream mitigated F contamination giving nearly 1:1 metal:oxide stoichiometries for both ZnO and AZO with little precursor-derived C contamination. ZnO and AZO thin film resistivities ranged from 14 to 28 Ω·cm for the former and 1.1 to 2.7 Ω·cm for the latter. - Highlights: • A second generation precursor was utilized for atmospheric pressure film growth. • Addition of water vapor to the carrier gas stream led to a marked reduction of ZnF{sub 2}. • Carbonaceous contamination from the precursor was minimal.

  16. Gold nanoparticles supported on magnesium oxide for CO oxidation

    Directory of Open Access Journals (Sweden)

    Bogdanchikova Nina

    2011-01-01

    Full Text Available Abstract Au was loaded (1 wt% on a commercial MgO support by three different methods: double impregnation, liquid-phase reductive deposition and ultrasonication. Samples were characterised by adsorption of N2 at -96°C, temperature-programmed reduction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Upon loading with Au, MgO changed into Mg(OH2 (the hydroxide was most likely formed by reaction with water, in which the gold precursor was dissolved. The size range for gold nanoparticles was 2-12 nm for the DIM method and 3-15 nm for LPRD and US. The average size of gold particles was 5.4 nm for DIM and larger than 6.5 for the other methods. CO oxidation was used as a test reaction to compare the catalytic activity. The best results were obtained with the DIM method, followed by LPRD and US. This can be explained in terms of the nanoparticle size, well known to determine the catalytic activity of gold catalysts.

  17. Anticancer activity of Ficus religiosa engineered copper oxide nanoparticles.

    Science.gov (United States)

    Sankar, Renu; Maheswari, Ramasamy; Karthik, Selvaraju; Shivashangari, Kanchi Subramanian; Ravikumar, Vilwanathan

    2014-11-01

    The design, synthesis, characterization and application of biologically synthesized nanomaterials have become a vital branch of nanotechnology. There is a budding need to develop a method for environmentally benign metal nanoparticle synthesis, that do not use toxic chemicals in the synthesis protocols to avoid adverse effects in medical applications. Here, it is a report on an eco-friendly process for rapid synthesis of copper oxide nanoparticles using Ficus religiosa leaf extract as reducing and protecting agent. The synthesized copper oxide nanoparticles were confirmed by UV-vis spectrophotometer, absorbance peaks at 285 nm. The copper oxide nanoparticles were analyzed with field emission-scanning electron microscope (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS) and X-ray diffraction (XRD) spectrum. The FE-SEM and DLS analyses exposed that copper oxide nanoparticles are spherical in shape with an average particle size of 577 nm. FT-IR spectral analysis elucidates the occurrence of biomolecules required for the reduction of copper oxide ions. Zeta potential studies showed that the surface charge of the formed nanoparticles was highly negative. The XRD pattern revealed that synthesized nanoparticles are crystalline in nature. Further, biological activities of the synthesized nanoparticles were confirmed based on its stable anti-cancer effects. The apoptotic effect of copper oxide nanoparticles is mediated by the generation of reactive oxygen species (ROS) involving the disruption of mitochondrial membrane potential (Δψm) in A549 cells. The observed characteristics and results obtained in our in vitro assays suggest that the copper nanoparticles might be a potential anticancer agent. PMID:25280701

  18. Characterization and Tribological Properties of Hard Anodized and Micro Arc Oxidized 5754 Quality Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    M. Ovundur

    2015-03-01

    Full Text Available This study was initiated to compare the tribological performances of a 5754 quality aluminum alloy after hard anodic oxidation and micro arc oxidation processes. The structural analyses of the coatings were performed using XRD and SEM techniques. The hardness of the coatings was determined using a Vickers micro-indentation tester. Tribological performances of the hard anodized and micro arc oxidized samples were compared on a reciprocating wear tester under dry sliding conditions. The dry sliding wear tests showed that the wear resistance of the oxide coating generated by micro arc oxidation is remarkably higher than that of the hard anodized alloy.

  19. Porous Spherical Cellulose Composites Coated by Aluminum (Ⅲ) Oxide and Silicone: Preparation,Characterization and Adsorption Behavior

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Porous spherical cellulose composite (PSCA) coated by aluminum (Ⅲ) oxide was prepared andmodified by organosilicone. SEM images of the surface morphology of the bead cellulose shows that it hasspherical shape and abundant porous structure on its surface. The mapping images of aluminum and silicon ofthe composite (PSCAS) present aluminum( Ⅲ ) oxide and silicone are uniformly dispersed on the surface. Theadsorption behavior of PSCAS toward metal ions was determined.

  20. Comparative Assessment of Antimicrobial Efficiency of Ionic Silver, Silver Monoxide, and Metallic Silver Incorporated onto an Aluminum Oxide Nanopowder Carrier

    International Nuclear Information System (INIS)

    The present paper provides comparative assessment of antimicrobial efficiency of ionic silver (Ag+), silver monoxide (Ag2O), and metallic silver (Ag) incorporated onto an aluminum oxide nanopowder carrier (Al2O3). The deposition of Ag+ ions, Ag2O nanoparticles, and Ag nanoparticles on an different phases of aluminum oxide nanopowder carrier was realized using consecutive stages of dry sol-gel method. The Al2O3-Ag+, Al2O3-Ag2O, and Al2O3-Ag nanopowders were widely characterized qualitatively and quantitatively by SEM, physical nitrogen sorption and XRD analyses. Results indicate that the Al2O3 nanopowders added with Ag+, Ag2O, and Ag, apart from phase composition, were not differing considerably from one another in terms of their morphology and physical properties. However, nanopowders of Al2O3-Ag were more agglomerated than Al2O3-Ag2O and Al2O3-Ag+ nanopowders. The antibacterial activity of the nanopowders was examined by the spread plate method using bacterial strains such as Escherichia coli, Sarcina lutea, and Bacillus subtilis. The best antibacterial properties against Sarcina lutea strain were achieved in the amorphous-Al2O3-Ag+ and Al2O3-Ag2O nanopowders, whereas the worst antimicrobial activity against Bacillus subtilis and Escherichia coli was shown by the Al2O3-Ag+ and Al2O3-Ag nanopowders. The observed increase of the antibacterial activity as the silver content was not however significant for Al2O3-Ag nanopowders. The results obtained in the present experiments show that the Al2O3-Ag+, Al2O3-Ag2O, and Al2O3-Ag nanopowders, possessing good bactericidal properties, can be produced by using consecutive stages of dry sol-gel method, and Al2O3 nanopowder added with Ag2O is considered as the best raw material in the production of antiseptic materials.

  1. Trends in the Catalytic CO Oxidation Activity of Nanoparticles

    DEFF Research Database (Denmark)

    Nørskov, Jens Kehlet; Falsig, Hanne; Larsen, Britt Hvolbæk;

    2008-01-01

    Going for gold: Density functional calculations show how gold nanoparticles are more active catalysts for CO oxidation than other metal nanoparticles. The high catalytic activity of nanosized gold clusters at low temperature is found to be related to the ability of low-coordinate metal atoms to a...

  2. Cerium oxide as conversion coating for the corrosion protection of aluminum

    Directory of Open Access Journals (Sweden)

    JELENA GULICOVSKI

    2013-11-01

    Full Text Available CeO2 coatings were formed on the aluminum after Al surface preparation, by dripping the ceria sol, previously prepared by forced hydrolysis of Ce(NO34. The anticorrosive properties of ceria coatings were investigated by the electrochemical impedance spectroscopy (EIS during the exposure to 0.03 % NaCl. The morphology of the coatings was examined by the scanning electron microscopy (SEM. EIS data indicated considerably larger corrosion resistance of CeO2-coated aluminum than for bare Al. The corrosion processes on Al below CeO2 coating are subjected to more pronounced diffusion limitations in comparison to the processes below passive aluminum oxide film, as the consequence of the formation of highly compact protective coating. The results show that the deposition of ceria coatings is an effective way to improve corrosion resistance for aluminum.

  3. Iron oxide and gold nanoparticles in cancer therapy

    Science.gov (United States)

    Gotman, Irena; Psakhie, Sergey G.; Lozhkomoev, Aleksandr S.; Gutmanas, Elazar Y.

    2016-08-01

    Continuous research activities in the field of nanomedicine in the past decade have, to a great extent, been focused on nanoparticle technologies for cancer therapy. Gold and iron oxide nanoparticles (NP) are two of the most studied inorganic nanomaterials due to their unique optical and magnetic properties. Both types of NPs are emerging as promising systems for anti-tumor drug delivery and for nanoparticle-mediated thermal therapy of cancer. In thermal therapy, localized heating inside tumors or in proximity of tumor cells can be induced, for example, with Au NPs by radiofrequency ablation heating or conversion of photon energy (photothermal therapy) and in iron oxide magnetic NPs by heat generation through relaxation in an alternating magnetic field (magnetic hyperthermia). Furthermore, the superparamagnetic properties of iron oxide nanoparticles have led to their use as potent MRI (magnetic resonance imaging) contrast agents. Surface modification/coating can produce NPs with tailored and desired properties, such as enhanced blood circulation time, stability, biocompatibility and water solubility. To target nanoparticles to specific tumor cells, NPs should be conjugated with targeting moieties on the surface which bind to receptors or other molecular structures on the cell surface. The article presents several approaches to enhancing the specificity of Au and iron oxide nanoparticles for tumor tissue by appropriate surface modification/functionalization, as well as the effect of these treatments on the saturation magnetization value of iron oxide NPs. The use of other nanoparticles and nanostructures in cancer treatment is also briefly reviewed.

  4. Popping of graphite oxide: application in preparing metal nanoparticle catalysts.

    Science.gov (United States)

    Gao, Yongjun; Chen, Xi; Zhang, Jiaguang; Asakura, Hiroyuki; Tanaka, Tsunehiro; Teramura, Kentaro; Ma, Ding; Yan, Ning

    2015-08-26

    A popcorn-like transformation of graphite oxide (GO) is reported and used to synthesize metal nanoparticle catalysts. The popping step is unique and essential, not only generating a high-surface-area support but also partially decomposing the metal precursors to form well-separated metal oxide nuclei, which would further evolve into highly dispersed and uniform-sized nanoparticles in the subsequent reduction. PMID:26179983

  5. Stem cell tracking using iron oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Bull E

    2014-03-01

    Full Text Available Elizabeth Bull,1 Seyed Yazdan Madani,1 Roosey Sheth,1 Amelia Seifalian,1 Mark Green,2 Alexander M Seifalian1,31UCL Centre for Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, University College London, London, 2Department of Physics, King’s College London, Strand Campus, London, UK; 3Royal Free London National Health Service Foundation Trust Hospital, London, UKAbstract: Superparamagnetic iron oxide nanoparticles (SPIONs are an exciting advancement in the field of nanotechnology. They expand the possibilities of noninvasive analysis and have many useful properties, making them potential candidates for numerous novel applications. Notably, they have been shown that they can be tracked by magnetic resonance imaging (MRI and are capable of conjugation with various cell types, including stem cells. In-depth research has been undertaken to establish these benefits, so that a deeper level of understanding of stem cell migratory pathways and differentiation, tumor migration, and improved drug delivery can be achieved. Stem cells have the ability to treat and cure many debilitating diseases with limited side effects, but a main problem that arises is in the noninvasive tracking and analysis of these stem cells. Recently, researchers have acknowledged the use of SPIONs for this purpose and have set out to establish suitable protocols for coating and attachment, so as to bring MRI tracking of SPION-labeled stem cells into common practice. This review paper explains the manner in which SPIONs are produced, conjugated, and tracked using MRI, as well as a discussion on their limitations. A concise summary of recently researched magnetic particle coatings is provided, and the effects of SPIONs on stem cells are evaluated, while animal and human studies investigating the role of SPIONs in stem cell tracking will be explored.Keywords: stem cells, nanoparticle, magnetic

  6. Melting and Solidification Behaviour of Bi-Pb Multiphase Alloy Nanoparticles Embedded in Aluminum Matrix.

    Science.gov (United States)

    Khan, Patan Yousaf; Biswas, Krishanu

    2015-01-01

    The present investigation reports the result of the investigation on the phase transformation of biphasic Bi-Pb alloy nanoparticles embedded in the aluminum matrix. The samples are prepared by rapid solidification route involving melt spinning of Al-6 wt% (Bi55.9Pb44.1) alloy on a rotating copper wheel in an argon-filled evacuated chamber. The detailed transmission electron microscope (TEM) investigation shows presence of near cuboctahedral shaped biphasic nano-inclusions consisting of the (Bi) solid solution and β, the intermediate phase. β constitutes bulk of the nanoparticle with (Bi) forming the cap. Both the phases bear distinct orientation relationship with the matrix. The compositional analysis indicates substantial increase in solid solubilities of Pb in the (Bi) and Bi in the β-phases as compared to the as-cast sample. Differential scanning calorimetric (DSC) studies indicate substantial superheating (16.4 K) of the embedded nanoparticles with appearance of sharp melting peak. The solidification is observed to be diffused, taking place over a large temperature range (344.5 K to 332 K). The in situ heating stage experiments carried out in TEM indicate formation of core shell morphology during heating with β forming the shell around (Bi). The melting starts from Al/β/(Bi) triple point and then the liquid spreads along matrix-particle interface. The solidification occurs in eutectic manner. PMID:26328350

  7. Supercritical Fluid Facilitated Growth of Copper and Aluminum Oxide Nanoparticles

    Science.gov (United States)

    Williams, Geoffrey L.; Vohs, Jason K.; Brege, Jonathan J.; Fahlman, Bradley D.

    2005-01-01

    Supercritical fluids (SCFs) possess properties that are intermediate between liquids and gases. The combination of supercritical fluid technology with advanced characterization techniques such as electron microscopy provided a practical and rewarding undergraduate laboratory experiment.

  8. Mueller Matrix of Specular Reflection Using an Aluminum Grating Surface with Oxide Nanofilm.

    Science.gov (United States)

    Qiu, Jun; Ran, Dongfang; Liu, Linhua; Hsu, Pei-Feng

    2016-06-01

    The accurate nondestructive and real-time determination of the critical dimensions of oxide nanofilms on periodic nanostructures has potential applications in nanofabrication techniques. Mueller ellipsometry is fast, accurate, nondestructive, and can be used in the ambient air. This study used the elements of a Mueller matrix of specular reflection, which is based on a Mueller ellipsometry method, to evaluate the thickness of an oxide nanofilm on an aluminum grating surface. By using non-traditional rigorous coupled-wave analysis (RCWA), we decomposed the Mueller matrix to obtain the relationship between the evaluated polarization properties of reflected light and the dimensions of oxide nanofilms on aluminum grating surfaces. We also quantitatively analyzed the Mueller matrix elements' variation due to the thicknesses of top, sidewall, and bottom oxides. We consider these oxide films are naturally formed and of nonuniform thickness on grating structures. The results show that the elements of Mueller matrix shift with the increasing of the uniform thickness of oxide at a fixed wavelength. Moreover, as oxide nanofilms on grating structures are nonuniform, the impact of the thickness of side wall oxide on the Mueller matrix elements is more obvious than that of top and bottom oxides at the relative larger incidence wavelength range. The finding of this work may facilitate the nondestructive and real-time measurement of the thickness of oxide nanofilms on metal gratings where the metal is easily oxidized. PMID:27129364

  9. Nanopatterning of Crystalline Silicon Using Anodized Aluminum Oxide Templates for Photovoltaics

    Science.gov (United States)

    Chao, Tsu-An

    A novel thin film anodized aluminum oxide templating process was developed and applied to make nanopatterns on crystalline silicon to enhance the optical properties of silicon. The thin film anodized aluminum oxide was created to improve the conventional thick aluminum templating method with the aim for potential large scale fabrication. A unique two-step anodizing method was introduced to create high quality nanopatterns and it was demonstrated that this process is superior over the original one-step approach. Optical characterization of the nanopatterned silicon showed up to 10% reduction in reflection in the short wavelength range. Scanning electron microscopy was also used to analyze the nanopatterned surface structure and it was found that interpore spacing and pore density can be tuned by changing the anodizing potential.

  10. Multiwalled Carbon Nanotubes Decorated with Cobalt Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    D. G. Larrude

    2012-01-01

    Full Text Available Multiwalled carbon nanotubes (MWCNTs synthesized by spray pyrolysis were decorated with cobalt oxide nanoparticles using a simple synthesis route. This wet chemistry method yielded nanoparticles randomly anchored to the surface of the nanotubes by decomposition of cobalt nitrate hexahydrate diluted in acetone. Electron microscopy analysis indicated that dispersed particles were formed on the MWCNTs walls. The average size increased with the increasing concentration of cobalt nitrate in acetone in the precursor mixture. TEM images indicated that nanoparticles were strongly attached to the tube walls. The Raman spectroscopy results suggested that the MWCNT structure was slightly damaged after the nanoparticle growth.

  11. Experimental Viscosity Measurements for Copper Oxide Nanoparticle Suspensions

    Institute of Scientific and Technical Information of China (English)

    李俊明; 李泽梁; 王补宣

    2002-01-01

    The viscosity of water with copper oxide nanoparticle suspensions was measured using capillary viscometers. The mass fractions of copper oxide nanoparticles in the experiment, w, varied between 0.02 and 0.10, and the temperature range was 30℃ to 80℃. The experimental results show that the temperature was the major factor affecting the viscosity of the nanoparticle suspensions, while the effect of the mass fraction on the viscosity was not so obvious as that of the temperature for the mass fractions chosen in the experiment. The effect of the capillary tube size on the viscosity was also found to be relatively important at higher mass fractions.

  12. Enhancement of oxidation resistance of NBD 200 silicon nitride ceramics by aluminum implantation

    Science.gov (United States)

    Mukundhan, Priya

    Silicon nitride (Si3N4) ceramics are leading candidates for high temperature structural applications. They have already demonstrated functional capabilities well beyond the limits of conventional metals and alloys in advanced diesel and turbine engines. However, the practical exploitation of these benefits is limited by their oxidation and associated degradation processes in chemically aggressive environments. Additives and impurities in Si3N4 segregate to the surface of Si3N 4 and accelerate its high temperature oxidation process. This study aims to investigate the oxidation behavior of Norton NBD 200 silicon nitride (hot isostatically pressed with ˜1 wt.% MgO) and its modification by aluminum surface alloying. NBD 200 samples tribochemically polished to a mirror finish (10 nm) were implanted with 5, 10, 20 and 30 at.% aluminum at multienergies and multi-doses to achieve a uniform implant depth distribution to 200 nm. Unimplanted and aluminum-implanted samples were oxidized at 800°--1100°C in 1 atm O2 for 0.5--10 hours. Oxidation kinetics was determined using profilometry in conjunction with etch patterning. The morphological, structural and chemical characteristics of the oxide were characterized by various analytical techniques such as scanning electron microscope and energy dispersive x-ray analysis, secondary ion mass spectrometry and x-ray photoelectron spectroscopy. Oxidation of NBD 200 follows parabolic kinetics in the temperature range investigated and the process is diffusion-controlled. The oxide layers are enriched with sodium and magnesium from the bulk of the Si3N 4. The much higher oxidation rate for NBD 200 silicon nitride than for other silicon nitride ceramics with a similar amount of MgO is attributed to the presence of sodium. The rate-controlling mechanism is the outward diffusion of Mg2+ from the grain boundaries to the oxide scale. Aluminum implantation alleviates the detrimental effects of Na+ and Mg2+; not only is the rate of oxidation

  13. Aerosol Fe Nanoparticles with the Passivating Oxide Shell

    International Nuclear Information System (INIS)

    Structure, state, transformations and interactions of iron oxide shell with the iron metallic core in aerosol Fe nano-particles has been studied by X-ray and electron diffraction, TEM, Moessbauer spectroscopy and magnetization measurements. A strong influence of the state of nanoparticles oxide shell has been revealed on their magnetization, coercive force and hysteresis loop shift. A long-term passivation of the particles has been shown to be caused by the primary amorphous oxide. The passivation ability of the oxide shell becomes essentially worse after heat treatment of powder, resulting in its crystallization. Basing on the obtained results, a qualitative mechanism of passivation for nanoparticles covered with amorphous oxide shell has been suggested

  14. Plasma-enhanced Chemical Vapor Deposition of Aluminum Oxide Using Ultrashort Precursor Injection Pulses

    NARCIS (Netherlands)

    Dingemans, G.; M. C. M. van de Sanden,; Kessels, W. M. M.

    2012-01-01

    An alternative plasma-enhanced chemical vapor deposition (PECVD) method is developed and applied for the deposition of high-quality aluminum oxide (AlOx) films. The PECVD method combines a continuous plasma with ultrashort precursor injection pulses. We demonstrate that the modulation of the precurs

  15. Propagation of nonequilibrium phonons in aluminum-oxide ceramics fabricated by cold isostatic pressing

    International Nuclear Information System (INIS)

    Propagation of slightly nonequilibrium phonons in aluminum-oxide ceramics fabricated by cold isostatic pressing has been studied. Assuming that phonon propagation in ceramic grains is ballistic, we have analyzed characteristics of the phonon scattering and drawn some conclusions about the nature of grain boundaries

  16. Fabrication, structural characterization and sensing properties of polydiacetylene nanofibers templated from anodized aluminum oxide

    Science.gov (United States)

    Polydiacetylene (PDA), a unique conjugated polymer, has shown its potential in the application of chem/bio-sensors and optoelectronics. In this work, we first infiltrated PDA monomer (10, 12-pentacosadiynoic acid, PCDA) melted into the anodized aluminum oxide template, and then illuminated the infil...

  17. Standard specification for nuclear-grade aluminum oxide-boron carbide composite pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This specification applies to pellets composed of mixtures of aluminum oxide and boron carbide that may be ultimately used in a reactor core, for example, in neutron absorber rods. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

  18. In-situ measurement of the electrical conductivity of aluminum oxide in HFIR

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J.; White, D.P.; Snead, L.L. [Oak Ridge National Lab., TN (United States)] [and others

    1996-10-01

    A collaborative DOE/Monbusho irradiation experiment has been completed which measured the in-situ electrical resistivity of 12 different grades of aluminum oxide during HFIR neutron irradiation at 450{degrees}C. No evidence for bulk RIED was observed following irradiation to a maximum dose of 3 dpa with an applied dc electric field of 200 V/mm.

  19. Oxidation of silicon implanted with high-dose aluminum

    International Nuclear Information System (INIS)

    Si (100) wafers were implanted with Al at 500 C to high doses at multi-energies and were oxidized in 1 atm flowing oxygen at 1,000--1,200 C. The morphology, structure, and oxidation behavior of the implanted and oxidized Si were studied using optical microscopy, atomic force microscopy, and cross-sectional transmission electron microscopy in conjunction with selected area electron diffraction and energy dispersive x-ray analysis. Large Al precipitates were formed and embedded near the surface region of the implanted Si. The oxidation rate of the Al-implanted Si wafers was lower than that of virgin Si. The unique morphology of the implanted Si results from rapid Al diffusion and segregation promoted by hot implantation. The reduction of the oxidation rate of Si by Al implantation is attributed to the preferential oxidation of Al and formation of a continuous diffusion barrier of Al2O3

  20. Dissolution of Oxide Films on Aluminum in Near Neutral Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, Hugh S.; Xu, Feng; Jeffcoate, Carrol S.

    1999-10-17

    Simple linear potentiodynamic cycling measurements have been made on abraded pure Al in borate, chromate, phosphate, sulfate and nitrate solutions. In borate and chromate solutions the currents continued to decrease with each subsequent cycle. In phosphate dissolution of the oxide takes place producing repetitive repeat curves. The current variations in borate and chromate were simulated using a high field conduction oxide growth model. Including oxide dissolution in the model simulated the phosphate behavior. Results in sulfate and nitrate solutions were more complex. The behavior in the sulfate solution was attributed to effects of sulfate the oxide/solution interface.

  1. Interaction effects in magnetic oxide nanoparticle systems

    Indian Academy of Sciences (India)

    Raksha Sharma; C Pratima; Subhalakshmi Lamba; S Annapoorni

    2005-10-01

    The interaction effects in magnetic nanoparticle system were studied through a Monte Carlo simulation. The results of simulations were compared with two different magnetic systems, namely, iron oxide polymer nanocomposites prepared by polymerization over core and nanocrystalline cobalt ferrite thin films prepared by sol–gel process. The size of the particles in the nanocomposites were estimated to be ∼ 15 nm with very little agglomeration. The low values of the coercivity obtained from the hysteresis measurements performed confirm that the system is superparamagnetic. SEM studies showed the cobalt ferrite films to have a nanocrystalline character, with particle sizes in the nanometer range. Hysteresis measurements performed on the thin films coated on silicon do not give evidence of the superparamagnetic transition up to room temperature and the coercivity is found to increase with decreasing film thickness. Comparison with simulations indicate that the nanocomposites behave like a strongly interacting array where exchange interactions lead to high blocking temperatures, whereas the films are representative of a semi-infinite array of magnetic clusters with weak interactions and thickness-dependent magnetic properties.

  2. Linear Sensing Response to Ethanol by Indium Oxide Nanoparticle Layers

    International Nuclear Information System (INIS)

    Indium oxide nanoparticles having well-defined particle sizes were synthesized using a chemical capping method. These nanoparticles were used for making the nanoparticle layers without altering the size and morphology of these particles. These nanoparticles and nanoparticle layers were characterized using XRD, TEM, HRTEM and AFM. The ethanol sensing behavior of the nanoparticle layers were studied at different ethanol concentrations. It was observed that the sensor response was linear to the ethanol concentration in the range of 10-1000 ppm. The ethanol sensing behavior has been explained on the basis of the creation of a depletion region due to the adsorbed oxygen and release of the electron in the conduction band in the presence of ethanol (as it takes away the adsorbed oxygen). The explanation has been supported by EDAX results.

  3. Omnidirectional excitation of sidewall gap-plasmons in a hybrid gold-nanoparticle/aluminum-nanopore structure

    Science.gov (United States)

    Lumdee, Chatdanai; Kik, Pieter G.

    2016-06-01

    The gap-plasmon resonance of a gold nanoparticle inside a nanopore in an aluminum film is investigated in polarization dependent single particle microscopy and spectroscopy. Scattering and transmission measurements reveal that gap-plasmons of this structure can be excited and observed under normal incidence excitation and collection, in contrast to the more common particle-on-a-mirror structure. Correlation of numerical simulations with optical spectroscopy suggests that a local electric field enhancement factor in excess of 50 is achieved under normal incidence excitation, with a hot-spot located near the top surface of the structure. It is shown that the strong field enhancement from this sidewall gap-plasmon mode can be efficiently excited over a broad angular range. The presented plasmonic structure lends itself to implementation in low-cost, chemically stable, easily addressable biochemical sensor arrays providing large optical field enhancement factors.

  4. In vitro toxicity of zinc oxide nanoparticles: a review

    International Nuclear Information System (INIS)

    The toxic effect of ZnO nanoparticles is due to their solubility. ZnO nanoparticles dissolve in the extracellular region, which in turn increases the intracellular [Zn2+] level. The mechanism for increased intracellular [Zn2+] level and ZnO nanoparticles dissolution in the medium is still unclear. Cytotoxicity, increased oxidative stress, increased intracellular [Ca2+] level, decreased mitochondrial membrane potential, and interleukin-8 productions occur in the BEAS-2B bronchial epithelial cells and A549 alveolar adenocarcinoma cells following the exposure of ZnO nanoparticles. Confluent C2C12 cells are more resistant to ZnO nanoparticles compared to the sparse monolayer. Loss of 3T3-L1 cell viability, membrane leakage, and morphological changes occurs due to exposure of ZnO nanoparticles. ZnO nanoparticle induces cytotoxicity and mitochondrial dysfunction in RKO colon carcinoma cells. The occurrence of apoptosis, increased ROS level, reduced mitochondrial activity and formation of tubular intracellular structures are reported following exposure of ZnO nanoparticles in skin cells. Macrophages, monocytes, and dendritic cells are affected by ZnO nanoparticles. In addition, genotoxicity is also induced. The present review summarizes the literature on in vitro toxicity of ZnO nanoparticles (10–100 nm) on various cell lines

  5. In vitro toxicity of zinc oxide nanoparticles: a review

    Energy Technology Data Exchange (ETDEWEB)

    Pandurangan, Muthuraman; Kim, Doo Hwan, E-mail: frenzram1980@gmail.com [Konkuk University, Department of Bioresources and Food Sciences (Korea, Republic of)

    2015-03-15

    The toxic effect of ZnO nanoparticles is due to their solubility. ZnO nanoparticles dissolve in the extracellular region, which in turn increases the intracellular [Zn{sup 2+}] level. The mechanism for increased intracellular [Zn{sup 2+}] level and ZnO nanoparticles dissolution in the medium is still unclear. Cytotoxicity, increased oxidative stress, increased intracellular [Ca{sup 2+}] level, decreased mitochondrial membrane potential, and interleukin-8 productions occur in the BEAS-2B bronchial epithelial cells and A549 alveolar adenocarcinoma cells following the exposure of ZnO nanoparticles. Confluent C2C12 cells are more resistant to ZnO nanoparticles compared to the sparse monolayer. Loss of 3T3-L1 cell viability, membrane leakage, and morphological changes occurs due to exposure of ZnO nanoparticles. ZnO nanoparticle induces cytotoxicity and mitochondrial dysfunction in RKO colon carcinoma cells. The occurrence of apoptosis, increased ROS level, reduced mitochondrial activity and formation of tubular intracellular structures are reported following exposure of ZnO nanoparticles in skin cells. Macrophages, monocytes, and dendritic cells are affected by ZnO nanoparticles. In addition, genotoxicity is also induced. The present review summarizes the literature on in vitro toxicity of ZnO nanoparticles (10–100 nm) on various cell lines.

  6. Characterization, sorption, and exhaustion of metal oxide nanoparticles as metal adsorbents

    Science.gov (United States)

    Engates, Karen Elizabeth

    Safe drinking water is paramount to human survival. Current treatments do not adequately remove all metals from solution, are expensive, and use many resources. Metal oxide nanoparticles are ideal sorbents for metals due to their smaller size and increased surface area in comparison to bulk media. With increasing demand for fresh drinking water and recent environmental catastrophes to show how fragile water supplies are, new approaches to water conservation incorporating new technologies like metal oxide nanoparticles should be considered as an alternative method for metal contaminant adsorbents from typical treatment methods. This research evaluated the potential of manufactured iron, anatase, and aluminum nanoparticles (Al2O3, TiO2, Fe2O3) to remove metal contaminants (Pb, Cd, Cu, Ni, Zn) in lab-controlled and natural waters in comparison to their bulk counterparts by focusing on pH, contaminant and adsorbent concentrations, particle size, and exhaustive capabilities. Microscopy techniques (SEM, BET, EDX) were used to characterize the adsorbents. Adsorption experiments were performed using 0.01, 0.1, or 0.5 g/L nanoparticles in pH 8 solution. When results were normalized by mass, nanoparticles adsorbed more than bulk particles but when surface area normalized the opposite was observed. Adsorption was pH-dependent and increased with time and solid concentration. Aluminum oxide was found to be the least acceptable adsorbent for the metals tested, while titanium dioxide anatase (TiO2) and hematite (alpha-Fe2O3) showed great ability to remove individual and multiple metals from pH 8 and natural waters. Intraparticle diffusion was likely part of the complex kinetic process for all metals using Fe2O3 but not TiO 2 nanoparticles within the first hour of adsorption. Adsorption kinetics for all metals tested were described by a modified first order rate equation used to consider the diminishing equilibrium metal concentrations with increasing metal oxides, showing faster

  7. Modelling the growth process of porous aluminum oxide film during anodization

    Science.gov (United States)

    Aryslanova, E. M.; Alfimov, A. V.; Chivilikhin, S. A.

    2015-11-01

    Currently it has become important for the development of metamaterials and nanotechnology to obtain regular self-assembled structures. One such structure is porous anodic alumina film that consists of hexagonally packed cylindrical pores. In this work we consider the anodization process, our model takes into account the influence of layers of aluminum and electrolyte on the rate of growth of aluminum oxide, as well as the effect of surface diffusion. In present work we consider those effects. And as a result of our model we obtain the minimum distance between centers of alumina pores in the beginning of anodizing process.

  8. Strengthening Aluminum Alloys for High Temperature Applications Using Nanoparticles of Al203 and Al3-X Compounds (X= Ti, V, Zr)

    Science.gov (United States)

    Lee, Jonathan A.

    2007-01-01

    In this paper the effect of nanoparticles A12O3 and A13-X compounds (X= Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their chemical stability and low diffusions rates in aluminum matrix at high temperatures. The strengthening mechanism for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. Samples were prepared from A12O3 nanoparticle preforms, which were produced using ceramic injection molding process and pressure infiltrated by molten aluminum. A12O3 nanoparticles can also be homogeneously mixed with aluminum powder and consolidated into samples through hot pressing and sintering. On the other hand, the Al3-X nanoparticles are produced as precipitates via in situ reactions with molten aluminum alloys using conventional casting techniques. The degree of alloy strengthening using nanoparticles will depend on the materials, particle size, shape, volume fraction, and mean inter-particle spacing.

  9. Lipidic nanovesicles stabilize suspensions of metal oxide nanoparticles.

    Science.gov (United States)

    Jiménez-Rojo, Noemi; Lete, Marta G; Rojas, Elena; Gil, David; Valle, Mikel; Alonso, Alicia; Moya, Sergio E; Goñi, Félix M

    2015-10-01

    We have studied the effect of adding lipid nanovesicles (liposomes) on the aggregation of commercial titanium oxide (TiO2), zinc oxide (ZnO), or cerium oxide (CeO2) nanoparticles (NPs) suspensions in Hepes buffer. Liposomes were prepared with pure phospholipids or mixtures of phospholipids and/or cholesterol. Changes in turbidity were recorded as a function of time, either of metal nanoparticles alone, or for a mixture of nanoparticles and lipidic nanovesicles. Lipid nanovesicles markedly decrease the NPs tendency to sediment irrespective of size or lipid compositions, thus keeping the metal oxide NPs in suspension. Cryo-electron microscopy, fluorescence anisotropy of TMA-DPH and general polarization of laurdan failed to reveal any major effect of the NPs on the lipid bilayer structure or phase state of the lipids. The above data may help in developing studies of the interaction of inhaled particles with lung surfactant lipids and alveolar macrophages. PMID:26301898

  10. Combined flame and electrodeposition synthesis of energetic coaxial tungsten-oxide/aluminum nanowire arrays.

    Science.gov (United States)

    Dong, Zhizhong; Al-Sharab, Jafar F; Kear, Bernard H; Tse, Stephen D

    2013-09-11

    A nanostructured thermite composite comprising an array of tungsten-oxide (WO2.9) nanowires (diameters of 20-50 nm and lengths of >10 μm) coated with single-crystal aluminum (thickness of ~16 nm) has been fabricated. The method involves combined flame synthesis of tungsten-oxide nanowires and ionic-liquid electrodeposition of aluminum. The geometry not only presents an avenue to tailor heat-release characteristics due to anisotropic arrangement of fuel and oxidizer but also eliminates or minimizes the presence of an interfacial Al2O3 passivation layer. Upon ignition, the energetic nanocomposite exhibits strong exothermicity, thereby being useful for fundamental study of aluminothermic reactions as well as enhancing combustion characteristics. PMID:23899165

  11. Luminescence properties of oxide films formed by anodization of aluminum in 12-tungstophosphoric acid

    International Nuclear Information System (INIS)

    In this paper, we have investigated luminescence properties of oxide films formed by anodization of aluminum in 12-tungstophosphoric acid. For the first time we have measured weak luminescence during anodization of aluminum in this electrolyte (so-called galvanoluminescence GL) and showed that there are wide GL bands in the visible region of the spectrum and observed two dominant spectral peaks. The first one is at about 425 nm, and the second one shifts with anodization voltage. As the anodization voltage approaches the breakdown voltage, a large number of sparks appear superimposed on the anodic GL. Several intensive band peaks were observed under breakdown caused by electron transitions in W, P, Al, O, H atoms. Furthermore, photoluminescence (PL) of anodic oxide films and anodic-spark formed oxide coatings were performed. In both cases wide PL bands in the range from 320 nm to 600 nm were observed.

  12. Investigation of sub-nm ALD aluminum oxide films by plasma assisted etch-through

    International Nuclear Information System (INIS)

    A new technique, called 'plasma defect etching' (PDE), is proposed for studying the continuity of ultra-thin layers. The PDE technique utilizes the extremely high selectivity in the deep reactive ion etching (DRIE) process, thus achieving visualization of the defects in the layer, because etching of substrate happens only through voids and microholes of the layer. The etch profile generally reproduces the non-continuous structure of the layer. This PDE technique was applied for the investigation of thin, sub-nm aluminum oxide films grown on silicon wafers by atomic layer deposition (ALD) technique. Silicon substrate was etched by SF6 at cryogenic temperatures in an inductively coupled plasma (ICP) reactor, exploiting the extremely high ratio of silicon/aluminum oxide etch rates in fluorine plasmas. The surface morphology was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The PDE method shows that in the case of water as an oxidation precursor, separate islands of aluminum oxide form during the five first ALD cycles. On the other hand, the use of ozone precursor helps to oxidize silicon surface and facilitates growth of a uniform layer

  13. Ultrafast laser induced periodic sub-wavelength aluminum surface structures and nanoparticles in air and liquids

    Energy Technology Data Exchange (ETDEWEB)

    Kuladeep, Rajamudili; Dar, Mudasir H.; Rao, D. Narayana, E-mail: dnrsp@uohyd.ac.in, E-mail: dnr-laserlab@yahoo.com [School of Physics, University of Hyderabad, Hyderabad 500046 (India); Deepak, K. L. N. [Department of Physics and Center for Research in Photonics, University of Ottawa, 150 Louis Pasteur, Ottawa K1N6N5, Ontario (Canada)

    2014-09-21

    In this communication, we demonstrate the generation of laser-induced periodic sub-wavelength surface structures (LIPSS) or ripples on a bulk aluminum (Al) and Al nanoparticles (NPs) by femtosecond (fs) laser direct writing technique. Laser irradiation was performed on Al surface at normal incidence in air and by immersing in ethanol (C₂H₅OH) and water (H₂O) using linearly polarized Ti:sapphire fs laser pulses of ~110 fs pulse duration and ~800 nm wavelength. Field emission scanning electron microscope is utilized for imaging surface morphology of laser written structures and it reveals that the spatial periodicity as well as the surface morphology of the LIPSS depends on the surrounding dielectric medium and also on the various laser irradiation parameters. The observed LIPSS have been classified as low spatial frequency LIPSS which are perpendicularly oriented to the laser polarization with a periodicity from 460 to 620 nm and high spatial frequency LIPSS which spectacles a periodicity less than 100 nm with the orientation parallel to the polarization of the incident laser beam. Fabricated colloidal solutions, which contain the Al NPs, were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). TEM results reveal the formation of internal cavities in Al NPs both in ethanol and water. Formation mechanism of LIPSS and cavities inside the nanoparticles are discussed in detail.

  14. Aluminum cladding oxidation of prefilmed in-pile fueled experiments

    Science.gov (United States)

    Marcum, W. R.; Wachs, D. M.; Robinson, A. B.; Lillo, M. A.

    2016-04-01

    A series of fueled irradiation experiments were recently completed within the Advanced Test Reactor Full size plate In center flux trap Position (AFIP) and Gas Test Loop (GTL) campaigns. The conduct of the AFIP experiments supports ongoing efforts within the global threat reduction initiative (GTRI) to qualify a new ultra-high loading density low enriched uranium-molybdenum fuel. This study details the characterization of oxide growth on the fueled AFIP experiments and cross-correlates the empirically measured oxide thickness values to existing oxide growth correlations and convective heat transfer correlations that have traditionally been utilized for such an application. This study adds new and valuable empirical data to the scientific community with respect to oxide growth measurements of highly irradiated experiments, of which there is presently very limited data. Additionally, the predicted oxide thickness values are reconstructed to produce an oxide thickness distribution across the length of each fueled experiment (a new application and presentation of information that has not previously been obtainable in open literature); the predicted distributions are compared against experimental data and in general agree well with the exception of select outliers.

  15. Biomimetic metal oxides for the extraction of nanoparticles from water

    Science.gov (United States)

    Mallampati, Ramakrishna; Valiyaveettil, Suresh

    2013-03-01

    Contamination of nanomaterials in the environment will pose significant health risks in the future. A viable purification method is necessary to address this problem. Here we report the synthesis and application of a series of metal oxides prepared using a biological template for the removal of nanoparticles from the aqueous environment. A simple synthesis of metal oxides such as ZnO, NiO, CuO, Co3O4 and CeO2 employing eggshell membrane (ESM) as a biotemplate is reported. The morphology of the metal oxide powders was characterized using electron microscopes and the lattice structure was established using X-ray diffraction methods. Extraction of nanoparticles from water was carried out to compare the efficiency of metal oxides. NiO showed good extraction efficiency in removing gold and silver nanoparticles from spiked water samples within an hour. Easy access and enhanced stability of metal oxides makes them interesting candidates for applications in industrial effluent treatments and water purifications.Contamination of nanomaterials in the environment will pose significant health risks in the future. A viable purification method is necessary to address this problem. Here we report the synthesis and application of a series of metal oxides prepared using a biological template for the removal of nanoparticles from the aqueous environment. A simple synthesis of metal oxides such as ZnO, NiO, CuO, Co3O4 and CeO2 employing eggshell membrane (ESM) as a biotemplate is reported. The morphology of the metal oxide powders was characterized using electron microscopes and the lattice structure was established using X-ray diffraction methods. Extraction of nanoparticles from water was carried out to compare the efficiency of metal oxides. NiO showed good extraction efficiency in removing gold and silver nanoparticles from spiked water samples within an hour. Easy access and enhanced stability of metal oxides makes them interesting candidates for applications in industrial

  16. The thickness of native oxides on aluminum alloys and single crystals

    International Nuclear Information System (INIS)

    Highlights: • We have determined the native oxide film thickness on several Al samples. • The results obtained from XRR and XPS show excellent agreement. • The results obtained from EIS show consistently thinner oxide films. • The oxides on the alloys are thicker than the oxides on the single crystals. - Abstract: We present results from measurements of the native oxide film thickness on four different industrial aluminum alloys and three different aluminum single crystals. The thicknesses were determined using X-ray reflectivity, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. In addition, atomic force microscopy was used for micro-structural studies of the oxide surfaces. The reflectivity measurements were performed in ultra-high vacuum, vacuum, ambient, nitrogen and liquid water conditions. The results obtained using X-ray reflectivity and X-ray photoelectron spectroscopy demonstrate good agreement. However, the oxide thicknesses determined from the electrochemical impedance spectroscopy show a larger discrepancy from the above two methods. In the present contribution the reasons for this discrepancy are discussed. We also address the effect of the substrate type and the presence of water on the resultant oxide thickness

  17. The thickness of native oxides on aluminum alloys and single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Evertsson, J., E-mail: jonas.evertsson@sljus.lu.se [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden); Bertram, F. [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden); Zhang, F. [KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas Vg 51, 100 44 Stockholm (Sweden); Rullik, L.; Merte, L.R.; Shipilin, M. [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden); Soldemo, M.; Ahmadi, S. [KTH Royal Institute of Technology, ICT, Material Physics, 16440 Kista (Sweden); Vinogradov, N.; Carlà, F. [ESRF, B.P. 220, 38043 Grenoble (France); Weissenrieder, J.; Göthelid, M. [KTH Royal Institute of Technology, ICT, Material Physics, 16440 Kista (Sweden); Pan, J. [KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas Vg 51, 100 44 Stockholm (Sweden); Mikkelsen, A. [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden); Nilsson, J.-O. [Sapa Technology, Kanalgatan 1, 612 31 Finspång (Sweden); Lundgren, E. [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden)

    2015-09-15

    Highlights: • We have determined the native oxide film thickness on several Al samples. • The results obtained from XRR and XPS show excellent agreement. • The results obtained from EIS show consistently thinner oxide films. • The oxides on the alloys are thicker than the oxides on the single crystals. - Abstract: We present results from measurements of the native oxide film thickness on four different industrial aluminum alloys and three different aluminum single crystals. The thicknesses were determined using X-ray reflectivity, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. In addition, atomic force microscopy was used for micro-structural studies of the oxide surfaces. The reflectivity measurements were performed in ultra-high vacuum, vacuum, ambient, nitrogen and liquid water conditions. The results obtained using X-ray reflectivity and X-ray photoelectron spectroscopy demonstrate good agreement. However, the oxide thicknesses determined from the electrochemical impedance spectroscopy show a larger discrepancy from the above two methods. In the present contribution the reasons for this discrepancy are discussed. We also address the effect of the substrate type and the presence of water on the resultant oxide thickness.

  18. Synthesis of zirconium oxide nanoparticle by sol-gel technique

    Energy Technology Data Exchange (ETDEWEB)

    Lim, H. S.; Ahmad, A.; Hamzah, H. [School of Chemical Science and Food Technology, Faculty of Science and Technology, National University of Malaysia, 43600 Bangi (Malaysia)

    2013-11-27

    Zirconium oxide nanoparticle is synthesized using sol-gel technique. Various mole ratio of ammonia solution and nitric acid relative to zirconium propoxide is added in the reaction to study the effect on the crystallinity and particle size on zirconium oxide particle. Zirconium oxide synthesized with nitric acid have the smallest particle size under FESEM image and show the increasing formation of crystalline tetragonal phase under XRD diffractogram.

  19. Hafnium oxide nanoparticles: toward an in vitro predictive biological effect?

    International Nuclear Information System (INIS)

    Hafnium oxide, NBTXR3 nanoparticles were designed for high dose energy deposition within cancer cells when exposed to ionizing radiation. The purpose of this study was to assess the possibility of predicting in vitro the biological effect of NBTXR3 nanoparticles when exposed to ionizing radiation. Cellular uptake of NBTXR3 nanoparticles was assessed in a panel of human cancer cell lines (radioresistant and radiosensitive) by transmission electron microscopy. The radioenhancement of NBTXR3 nanoparticles was measured by the clonogenic survival assay. NBTXR3 nanoparticles were taken up by cells in a concentration dependent manner, forming clusters in the cytoplasm. Differential nanoparticle uptake was observed between epithelial and mesenchymal or glioblastoma cell lines. The dose enhancement factor increased with increase NBTXR3 nanoparticle concentration and radiation dose. Beyond a minimum number of clusters per cell, the radioenhancement of NBTXR3 nanoparticles could be estimated from the radiation dose delivered and the radiosensitivity of the cancer cell lines. Our preliminary results suggest a predictable in vitro biological effect of NBTXR3 nanoparticles exposed to ionizing radiation

  20. Trapping Iron Oxide into Hollow Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Sun Xiankai

    2011-01-01

    Full Text Available Abstract Synthesis of the core/shell-structured Fe3O4/Au nanoparticles by trapping Fe3O4 inside hollow Au nanoparticles is described. The produced composite nanoparticles are strongly magnetic with their surface plasmon resonance peaks in the near infrared region (wavelength from 700 to 800 nm, combining desirable magnetic and plasmonic properties into one nanoparticle. They are particularly suitable for in vivo diagnostic and therapeutic applications. The intact Au surface provides convenient anchorage sites for attachment of targeting molecules, and the particles can be activated by both near infrared lights and magnetic fields. As more and more hollow nanoparticles become available, this synthetic method would find general applications in the fabrication of core–shell multifunctional nanostructures.

  1. Antioxidant activity of levan coated cerium oxide nanoparticles.

    Science.gov (United States)

    Kim, Sun-Jung; Chung, Bong Hyun

    2016-10-01

    Levan coated cerium oxide nanoparticles (LCNPs) with the enhanced antioxidant activity were successfully synthesized and characterized. Levan and their derivatives are attractive for biomedical applications attributable to their antioxidant, anti-inflammation and anti-tumor properties. LCNPs were synthesized using the one-pot and green synthesis system with levan. For production of nanoparticles, levan plays a role as a stabilizing and reducing agent. Fourier transform infrared spectroscopy (FT-IR) analysis showed that LCNPs successfully synthesized. The morphology and size of nanoparticles were confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). LCNPs have good water solubility and stability. The conjugation of levan with cerium oxide nanoparticles improved antioxidant activity. Moreover the level of ROS was reduced after treatment of LCNPs to H2O2 stimulated NIH3T3 cells. These results demonstrate that the LCNPs are useful for applying of treatment of ROS induced diseases. PMID:27312651

  2. Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng;

    2014-01-01

    With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite-1 is reported and their high...... activity and selectivity for the catalytic gas-phase oxidation of ethanol are demonstrated. The zeolites are modified by a recrystallization process, which creates intraparticle voids and mesopores that facilitate the formation of small and disperse nanoparticles upon simple impregnation. The individual...... zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2-3nm that are distributed inside the zeolites rather than on the outer surface. The encapsulated nanoparticles have good stability and result in 50% conversion of ethanol with 98...

  3. Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng;

    2014-01-01

    With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite‐1 is reported and their high...... activity and selectivity for the catalytic gas‐phase oxidation of ethanol are demonstrated. The zeolites are modified by a recrystallization process, which creates intraparticle voids and mesopores that facilitate the formation of small and disperse nanoparticles upon simple impregnation. The individual...... zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2–3 nm that are distributed inside the zeolites rather than on the outer surface. The encapsulated nanoparticles have good stability and result in 50 % conversion of ethanol with 98...

  4. Biosynthesis of Yttrium oxide nanoparticles using Acalypha indica leaf extract

    Indian Academy of Sciences (India)

    S K Kannan; M Sundrarajan

    2015-08-01

    In this study, the synthesis of Yttrium oxide (Y2O3) nanoparticles was carried out from Acalypha indica leaf extract. The synthesized nanoparticles were characterized by using X-ray diffraction, scanning electron microscope, energy-dispersive X-ray spectrometer and transmission electron microscope for structural confirmation. The studies clearly indicate that the synthesized Y2O3 nanoparticle is a crystalline material with a particle size from 23 to 66 nm. Further analysis was carried out by Fourier transform infrared spectroscopy, to provide the evidence for the presence of Y–O–Y and O–Y–O stretchings in the synthesized Y2O3 nanoparticles. Thermogravimetric and differential scanning calorimetry analyses gave the thermal stability of Y2O3 nanoparticles. The results of the antibacterial studies conducted by using the synthesized Y2O3 revealed an increasing rate of antibacterial behaviour with pathogens.

  5. Synthesis of Monodisperse Iron Oxide Nanoparticles without Surfactants

    Directory of Open Access Journals (Sweden)

    Xiao-Chen Yang

    2014-01-01

    Full Text Available Monodisperse iron oxide nanoparticles could be successfully synthesized with two kinds of precipitants through a precipitation method. As-prepared nanoparticles in the size around 10 nm with regular spherical-like shape were achieved by adjusting pH values. NaOH and NH3·H2O were used as two precipitants for comparison. The average size of nanoparticles with NH3·H2O precipitant got smaller and represented better dispersibility, while nanoparticles with NaOH precipitant represented better magnetic property. This work provided a simple method without using any organic solvents, organic metal salts, or surfactants which could easily obtain monodisperse nanoparticles with tunable morphology.

  6. Differential plasma protein binding to metal oxide nanoparticles

    International Nuclear Information System (INIS)

    Nanoparticles rapidly interact with the proteins present in biological fluids, such as blood. The proteins that are adsorbed onto the surface potentially dictate the biokinetics of the nanomaterials and their fate in vivo. Using nanoparticles with different sizes and surface characteristics, studies have reported the effects of physicochemical properties on the composition of adsorbed plasma proteins. However, to date, few studies have been conducted focusing on the nanoparticles that are commonly exposed to the general public, such as the metal oxides. Using previously established ultracentrifugation approaches, two-dimensional gel electrophoresis and mass spectrometry, the current study investigated the binding of human plasma proteins to commercially available titanium dioxide, silicon dioxide and zinc oxide nanoparticles. We found that, despite these particles having similar surface charges in buffer, they bound different plasma proteins. For TiO2, the shape of the nanoparticles was also an important determinant of protein binding. Agglomeration in water was observed for all of the nanoparticles and both TiO2 and ZnO further agglomerated in biological media. This led to an increase in the amount and number of different proteins bound to these nanoparticles. Proteins with important biological functions were identified, including immunoglobulins, lipoproteins, acute-phase proteins and proteins involved in complement pathways and coagulation. These results provide important insights into which human plasma proteins bind to particular metal oxide nanoparticles. Because protein absorption to nanoparticles may determine their interaction with cells and tissues in vivo, understanding how and why plasma proteins are adsorbed to these particles may be important for understanding their biological responses.

  7. Temperature evolution of copper oxide nanoparticles in porous glasses

    International Nuclear Information System (INIS)

    The temperature evolution of copper oxide nanoparticles in the temperature range of 1.5–250 K has been investigated by thermal-neutron diffraction. CuO particles were obtained by Cu(NO3)2 · 3H2O decomposition directly in the pores of porous glass with an average pore diameter of 7 nm. The characteristic nanoparticle size and linear thermal expansion coefficients have been determined.

  8. Potential toxicity of superparamagnetic iron oxide nanoparticles (SPION)

    OpenAIRE

    Neenu Singh; Jenkins, Gareth J. S.; Romisa Asadi; Doak, Shareen H.

    2010-01-01

    Superparamagnetic iron oxide nanoparticles (SPION) are being widely used for various biomedical applications, for example, magnetic resonance imaging, targeted delivery of drugs or genes, and in hyperthermia. Although, the potential benefits of SPION are considerable, there is a distinct need to identify any potential cellular damage associated with these nanoparticles. Besides focussing on cytotoxicity, the most commonly used determinant of toxicity as a result of exposure to SPION, this rev...

  9. Hydrothermal Synthesis of Indium Tin Oxide Nanoparticles without Chlorine Contamination

    International Nuclear Information System (INIS)

    Indium tin oxide (In2Sn1-xO5-y) nanoparticles were synthesized by hydrothermal method from stable indium tin acetylacetone complexes and post annealing at 600 .deg. C. The absence of chlorine ions shortened the synthesis process, decreased the particle agglomeration and improved the particle purity. The introduced complexing ligand acetylacetone decreased the obtained nanoparticle size. The improved powder properties accelerated the sintering of the In2Sn1-xO5-y nanoparticles and reached a relative density of 96.4% when pressureless sintered at 1400 .deg. C

  10. Enhanced formic acid oxidation on Cu-Pd nanoparticles

    Science.gov (United States)

    Dai, Lin; Zou, Shouzhong

    Developing catalysts with high activity and high resistance to surface poisoning remains a challenge in direct formic acid fuel cell research. In this work, copper-palladium nanoparticles were formed through a galvanic replacement process. After electrochemically selective dissolution of surface Cu, Pd-enriched Cu-Pd nanoparticles were formed. These particles exhibit much higher formic acid oxidation activities than that on pure Pd nanoparticles, and they are much more resistant to the surface poisoning. Possible mechanisms of catalytic activity enhancement are briefly discussed.

  11. Study of structural and optical properties of cupric oxide nanoparticles

    Science.gov (United States)

    Dhineshbabu, N. R.; Rajendran, V.; Nithyavathy, N.; Vetumperumal, R.

    2015-09-01

    In this study, cupric oxide (CuO) nanoparticles were synthesized via sonochemical method. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope, and transmission electron microscopy. The spherical CuO nanoparticles were dispersed in sodium hexametaphosphate under sonication (25 kHz) to analyze the particle size distribution and UV absorption spectra. Using these absorption spectra, we further examined the CuO nanoparticle to explore the possibility of using them as a material for applications such as solar cell and textile production.

  12. Magnetic irone oxide nanoparticles in photosynthetic systems

    International Nuclear Information System (INIS)

    Full text : It was found and studied the effect of biogenic formation of magnetic inclusions in photosynthetic systems - in various higher plants under the influence of some external stress factors (radiation impact, moisture deficit) and in a model system - a suspension of chloroplasts. For registration and characterization of magnetic nanoparticles in the samples used EPR spectrometer because superparamagnetic and ferromagnetic nanoparticles have a chcracteristic signals of electron magnetic resonance. For direct visualization of magnetic nanoparticles it was used the method of transmission electron microscopy

  13. Size-selected copper oxide nanoparticles synthesized by laser ablation

    International Nuclear Information System (INIS)

    Size-tuned copper oxide nanoparticles with sizes of 9, 12, and 15 nm were fabricated by laser ablation and on-line size selection using a differential mobility analyzer at a gas pressure of 666 Pa. The dependence of the particle properties on the in situ annealing temperatures and selection sizes was investigated. The crystalline phases of the nanoparticles fabricated at temperatures below 973 K were assigned to monoclinic cupric oxide (CuO) which converted into cubic cuprous oxide (Cu2O) when the annealing temperature was above 1,173 K. This indicates that the crystalline phases can be easily controlled by changing the annealing temperature. TEM images confirmed that well-crystallized and well-dispersed CuO and Cu2O nanoparticles with narrow size distributions were obtained using this method. This fabrication process is useful and promising for the future investigation of the intrinsic size-dependent properties of CuO and Cu2O.

  14. Facile synthesis of cuprous oxide nanoparticles by plasma electrochemistry

    Science.gov (United States)

    Liu, Jiandi; Chen, Qiang; Li, Junshuai; Xiong, Qing; Yue, Guanghui; Zhang, Xianhui; Yang, Size; Huo Liu, Qing

    2016-07-01

    We report on a simple plasma electrochemistry method for synthesizing cuprous oxide (Cu2O) nanoparticles in the presence of glucose. In this system, Ar plasma in contact with a NaCl solution was used as one electrode, and a Cu plate was immersed in the solution as the counter electrode. The plasma-solution interaction produced many reducing and oxidizing species which can react with the Cu ions released from the Cu electrode. Cu2O nanoparticles, with an average diameter of 22 +/- 6 nm, were formed under the competition of reducing and oxidizing reactions in the solution. The results show that the glucose added in the electrolyte strongly influences the properties of the products. Corresponding to high, medium, and low concentrations of glucose, the products were nanoparticles from amorphous Cu2O, polycrystalline Cu2O, and a mixture of polycrystalline Cu2O and Cu2Cl(OH)3, respectively.

  15. Markers of oxidative stress in exhaled breath of workers exposed to iron oxide nanoparticles are elevated

    Czech Academy of Sciences Publication Activity Database

    Pelclová, D.; Fenclová, Z.; Navrátil, Tomáš; Vlčková, Š.; Syslová, K.; Kuzma, Marek; Ždímal, Vladimír; Schwarz, Jaroslav; Pušman, Jan; Zíková, Naděžda; Zakharov, S.; Machajová, M.; Kačer, P.

    2014-01-01

    Roč. 7, Suppl. 1 (2014), s. 69-70. ISSN 1337-6853 Institutional support: RVO:61388971 ; RVO:61388955 ; RVO:67985858 Keywords : oxidative stress * exhaled breath * nanoparticles Subject RIV: CF - Physical ; Theoretical Chemistry

  16. Iron oxide nanoparticles for magnetically assisted patterned coatings

    International Nuclear Information System (INIS)

    Iron oxide nanoparticles able to magnetically assemble during the curing stage of a polymeric support to create micro-scale surface protuberances in a controlled manner were prepared and characterized. The bare Fe3O4 particles were obtained by two methods: co-precipitation from an aqueous solution containing Fe3+/Fe2+ ions with a molar ratio of 2:1 and partial oxidation of ferrous ions in alkaline conditions. The products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and magnetization measurement. They were subsequently functionalized using oleic acid, sodium oleate, or non-ionic surfactant mixtures with various hydrophilic to lipophilic balance (HLB) values. Composite nanoparticle-polymer films prepared by spraying were deposited and cured by drying on glass slides under a static magnetic field in the range of 1.5–5.5 mT. Magnetic field generated surface roughness was evidenced by optical and scanning electron microscopy. The optimum hierarchical patterning was obtained with the nanoparticles produced by partial oxidation and functionalized with hydrophobic surfactants. Possible applications may include ice-phobic composite coatings. - Highlights: • Magnetite nanoparticles bearing variable hydrophobic functionality were synthesized. • Partial oxidation in alkaline solution is proved to be the optimum synthesis method. • Nanoparticle assembly in magnetic field produced films with hierarchical roughness. • Coating patterning is controlled by surfactant nature and magnetic field strength. • Possible applications in composite films with ice-phobic properties are suggested

  17. Iron oxide nanoparticles for magnetically assisted patterned coatings

    Energy Technology Data Exchange (ETDEWEB)

    Dodi, Gianina; Hritcu, Doina, E-mail: dhritcu@ch.tuiasi.ro; Draganescu, Dan; Popa, Marcel I.

    2015-08-15

    Iron oxide nanoparticles able to magnetically assemble during the curing stage of a polymeric support to create micro-scale surface protuberances in a controlled manner were prepared and characterized. The bare Fe{sub 3}O{sub 4} particles were obtained by two methods: co-precipitation from an aqueous solution containing Fe{sup 3+}/Fe{sup 2+} ions with a molar ratio of 2:1 and partial oxidation of ferrous ions in alkaline conditions. The products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and magnetization measurement. They were subsequently functionalized using oleic acid, sodium oleate, or non-ionic surfactant mixtures with various hydrophilic to lipophilic balance (HLB) values. Composite nanoparticle-polymer films prepared by spraying were deposited and cured by drying on glass slides under a static magnetic field in the range of 1.5–5.5 mT. Magnetic field generated surface roughness was evidenced by optical and scanning electron microscopy. The optimum hierarchical patterning was obtained with the nanoparticles produced by partial oxidation and functionalized with hydrophobic surfactants. Possible applications may include ice-phobic composite coatings. - Highlights: • Magnetite nanoparticles bearing variable hydrophobic functionality were synthesized. • Partial oxidation in alkaline solution is proved to be the optimum synthesis method. • Nanoparticle assembly in magnetic field produced films with hierarchical roughness. • Coating patterning is controlled by surfactant nature and magnetic field strength. • Possible applications in composite films with ice-phobic properties are suggested.

  18. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1994-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Boron by Titrimetry 7 to 13 Separation of Boron for Mass Spectrometry 14 to 19 Isotopic Composition by Mass Spectrometry 20 to 23 Separation of Halides by Pyrohydrolysis 24 to 27 Fluoride by Ion-Selective Electrode 28 to 30 Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 31 to 33 Trace Elements by Emission Spectroscopy 34 to 46 1.3 The values stated in SI units are to be regarded as the standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. (F...

  19. Interactions between nitric oxide and plant hormones in aluminum tolerance

    OpenAIRE

    He, Huyi; He, Longfei; Gu, Minghua

    2012-01-01

    Nitric oxide (NO) is involved, together with plant hormones, in the adaptation to Al stress in plants. However, the mechanism by which NO and plant hormones interplay to improve Al tolerance are still unclear. We have recently shown that patterns of plant hormones alteration differ between rye and wheat under Al stress. NO may enhance Al tolerance by regulating hormonal equilibrium in plants, as a regulator of plant hormones signaling. In this paper, some unsolved issues are discussed based o...

  20. The electrochemisty of surface modified <10 nm metal oxide nanoparticles

    Science.gov (United States)

    Roberts, Joseph J. P.

    Chapter One provides a general introduction of the research on metal oxide nanoparticles (MOx), highlighting their synthesis, surface modification, and functionalization. Emphasis is given to the different synthetic route for producing small (electrode (microE) experiments. Chapter Four investigates spectroscopic tagging of ITO and ZrO2 nanoparticles as well as electrochemical tagging of ZrO 2 and IrO2 nanoparticles. An unbound azo-dye was synthesized and attempts were made to attach the dye to the surface of ITO nanoparticles. Imine couple between a spectroscopic tag and ZrO2 nanoparticles was also explored, but resulted in very low surface coverages. ZrO2 nanoparticles were also ferrocene tagged using previously discussed siloxane chemistry as well as a new route using click chemistry with an azo-phosphate ligand. A similar approach was taken with hydrolytically synthesized IrO 2 and is included for comparison. Chapter Five studies the multivalent electrochemistry of 4 nm magnetite nanoparticles. These nanoparticles are synthesized via thermal degradation and capped with citric acid to make them water soluble. pH dependent electrochemistry was discovered and characterized using cyclic voltammetry, chronoamperometry, and rotating disk electrode experiments. Two separate electrochemical species are present and undergo two irreversible, but separate electrochemical reactions; Fe(II) → Fe (III) and Fe(III) → Fe(II).

  1. 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). PMID:19441424

  2. Aluminum oxide sputtering: a new approach to understanding the sputtering process for binary targets

    International Nuclear Information System (INIS)

    The relative abundances of the products Al, Al2O, and AlO sputtered in 15- and 40-kV Ar+ and 15-kV H+ bombardments of aluminum oxide targets (anodized film, polycrystalline disk, sapphire) are functions of the target material and of the nature, flux, and fluence of the ion beam. This finding suggests that, in collisional sputtering, the material's sensitive parameters are the surface binding energies of the sputtered species. These energies are functions of the surface composition present at the moment of a particular sputtering event and should be identified with the partial molar enthalpy of vaporization of a particular species. The aluminum oxide species--Al, Al2O, AlO, Al2O2, AlO2, Al(O2)2, and AlO3--are characterized by matrix isolation spectroscopy aided by O18 isotopic substitution experiments. 12 figures, 4 tables

  3. Preparation of Graphene Oxide Stabilized Nickel Nanoparticles with Thermal Effusivity Properties by Laser Ablation Method

    OpenAIRE

    Amir Reza Sadrolhosseini; Noor, A. S. M.; Kamyar Shameli; Alireza Kharazmi; N. M. Huang; Mahdi, M. A.

    2013-01-01

    Nickel nanoparticles were dispersed uniformly in a graphene oxide solution, using a laser ablation technique with different ablation times that ranged from 5 to 20 minutes. The results indicate that the nickel nanoparticle sizes inside the graphene oxide decreased, and the volume fraction for the nickel nanoparticles in the graphene oxide increased with an increasing ablation time. Further, using Fourier Transform Infrared Spectroscopy, the nickel nanoparticles in the graphene oxide demonstra...

  4. Structure of graphene oxide dispersed with ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Rishikesh, E-mail: rishikesh.yadav62@gmail.com; Pandey, Devendra K., E-mail: devendrakphy@gmail.com [School of Nanotechnology, Rajiv Gandhi Proudyogiki Vishwavidalaya, Bhopal, M.P. (India); Khare, P. S., E-mail: purnimaswarup@hotmail.com [Department of Physics, Rajiv Gandhi Proudyogiki Vishwavidalaya, Bhopal M.P. (India)

    2014-10-15

    Graphene has been proposed as a promising two-dimensional nanomaterial with outstanding electronic, optical, thermal and mechanical properties for many applications. In present work a process of dispersion of graphene oxide with ZnO nanoparticles in ethanol solution with different pH values, have been studied. Samples have been characterized by XRD, SEM, PL, UV-visible spectroscopy and particles size measurement. The results analysis indicates overall improved emission spectrum. It has been observed that the average diameter of RGO (Reduced Graphene Oxide) decreases in presence of ZnO nanoparticles from 3.8μm to 0.41μm.

  5. Effect of conditions of thermal treatment on the porous structure of an aluminum oxide-containing nanofibrous aerogel

    Science.gov (United States)

    Markova, E. B.; Krasil'nikova, O. K.; Grankina, T. Yu.; Serov, Yu. M.

    2016-08-01

    The effect the conditions of thermal treatment have on a specific surface and the number of primary adsorption centers is studied. The relationship between changing adsorption characteristics and changes in the structure of nanofibrous aluminum oxide is considered.

  6. Radial Combustion Propagation in Iron(III) Oxide/Aluminum Thermite Mixtures

    OpenAIRE

    Durães, Luísa; Campos, José; Portugal, António

    2006-01-01

    The self-sustained thermite reaction between iron oxide (Fe2O3) and aluminum is a classical source of energy. In this work the radial combustion propagation on thin circular samples of stoichiometric and over aluminized Fe2O3/Al thermite mixtures is studied. The radial geometry allows an easy detection of sample heterogeneities and the observation of the combustion behavior in their vicinity. The influence of factors like reactant mixtures stoichiometry, samples green density and system geome...

  7. Commensurate vortex pinning in Nb films patterned onto anodized aluminum oxide

    International Nuclear Information System (INIS)

    Anodic aluminum oxide templates containing extended arrays of holes with ∼30-nm diameter and approximately 128-nm spacing were sputter-coated with Nb. We find pronounced matching effects in the transport and magnetization measurements beyond 4 kOe. In addition, we observe Little-Parks oscillations of the superconducting critical temperature. We compare the flux pinning in the patterned samples to unpatterned reference samples and find a significant enhancement of the critical current

  8. Characterization of Lipid Bilayer Formation in Aligned Nanoporous Aluminum Oxide Nanotube Arrays

    OpenAIRE

    Karp, Ethan S.; Newstadt, Justin P.; Chu, Shidong; Lorigan, Gary A.

    2007-01-01

    Aligning lipid bilayers in nanoporous anodized aluminum oxide (AAO) is a new method to help study membrane proteins by electron paramagnetic resonance (EPR) and solid-state nuclear magnetic resonance (NMR) spectroscopic methods. The ability to maintain hydration, sample stability, and compartmentalization over long periods of time, and to easily change solvent composition are major advantages of this new method. To date, 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) has been the onl...

  9. Mussel-Inspired Polydopamine Coated Iron Oxide Nanoparticles for Biomedical Application

    Directory of Open Access Journals (Sweden)

    Xiangling Gu

    2015-01-01

    Full Text Available Mussel-inspired polydopamine (PDA coated iron oxide nanoparticles have served as a feasible, robust, and functional platform for various biomedical applications. However, there is scarcely a systemic paper reviewed about such functionalising nanomaterials to date. In this review, the synthesis of iron oxide nanoparticles, the mechanism of dopamine self-oxidation, the interaction between iron oxide and dopamine, and the functionality and the safety assessment of dopamine modified iron oxide nanoparticles as well as the biomedical application of such nanoparticles are discussed. To enlighten the future research, the opportunities and the limitations of functionalising iron oxide nanoparticles coated with PDA are also analyzed.

  10. Growth behavior of anodic oxide formed by aluminum anodizing in glutaric and its derivative acid electrolytes

    Science.gov (United States)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2014-12-01

    The growth behavior of anodic oxide films formed via anodizing in glutaric and its derivative acid solutions was investigated based on the acid dissociation constants of electrolytes. High-purity aluminum foils were anodized in glutaric, ketoglutaric, and acetonedicarboxylic acid solutions under various electrochemical conditions. A thin barrier anodic oxide film grew uniformly on the aluminum substrate by glutaric acid anodizing, and further anodizing caused the film to breakdown due to a high electric field. In contrast, an anodic porous alumina film with a submicrometer-scale cell diameter was successfully formed by ketoglutaric acid anodizing at 293 K. However, the increase and decrease in the temperature of the ketoglutaric acid resulted in non-uniform oxide growth and localized pitting corrosion of the aluminum substrate. An anodic porous alumina film could also be fabricated by acetonedicarboxylic acid anodizing due to the relatively low dissociation constants associated with the acid. Acid dissociation constants are an important factor for the fabrication of anodic porous alumina films.

  11. Preparation and analysis of anodic aluminum oxide films with continuously tunable interpore distances

    Science.gov (United States)

    Qin, Xiufang; Zhang, Jinqiong; Meng, Xiaojuan; Deng, Chenhua; Zhang, Lifang; Ding, Guqiao; Zeng, Hao; Xu, Xiaohong

    2015-02-01

    Nanoporous anodic aluminum oxides are often used as templates for preparation of nanostructures such as nanodot, nanowire and nanotube arrays. The interpore distance of anodic aluminum oxide is the most important parameter in controlling the periodicity of these nanostructures. Herein we demonstrate a simple and yet powerful method to fabricate ordered anodic aluminum oxides with continuously tunable interpore distances. By using mixed solution of citric and oxalic acids with different molar ratio, the range of anodizing voltages within which self-ordered films can be formed were extended to between 40 and 300 V, resulting in the interpore distances change from 100 to 750 nm. Our work realized very broad range of interpore distances in a continuously tunable fashion and the experiment processes are easily controllable and reproducible. The dependence of the interpore distances on acid ratios in mixed solutions was discussed through analysis of anodizing current and it was found that the effective dissociation constant of the mixed acids is of great importance. The interpore distances achieved are comparable to wavelengths ranging from UV to near IR, and may have potential applications in optical meta-materials for photovoltaics and optical sensing.

  12. Anodic Aluminum Oxide Templates for Nano wires Array Fabrication

    International Nuclear Information System (INIS)

    This paper reports on the process developed to fabricate anodic aluminium oxide (AAO) templates suitable for the fabrication of nano wire arrays. Anodization process has been used to fabricate the AAO templates with pore diameters ranging from 15 nm to 30 nm. Electrodeposition of parallel arrays of high aspect ratio nickel nano wires were demonstrated using these fabricated AAO templates. The nano wires produced were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the orientations of the electrodeposited nickel nano wires were governed by the deposition current and electrolyte conditions. (author)

  13. Elaboration of aluminum oxide-based graphite containing castables

    Science.gov (United States)

    Zhou, Ningsheng

    The aim of this work was set to develop effective and practicable new methods to incorporate natural flake graphite (FG) into the Al2O 3 based castables for iron and steel making applications. Three approaches, viz. micro-pelletized graphite (PG), crushed briquette of Al2O3-graphite (BAG) and TiO2 coated graphite (CFG), have been developed to insert flake graphite into Al2O 3 rich Al2O3-SiC based and Al2O 3-MgO based castables. These approaches were put into effect as countermeasures against the problems caused by FG in order: (1) to agglomerate the FG powders so as to decrease the specific surface area; (2) to diminish the density difference by using crushed carbon bonded compact of oxide-FG mixture; (3) to modify the surface of the flake graphite by forming hydrophilic coating; (4) to control the dispersion state of the graphite in the castable to maintain enough bonding strength; and (5) to use appropriate antioxidants to inhibit the oxidation of FG. The whole work was divided into two stages. In stage one, Al2O 3-SiC-C castables were dealt with to compare 4 modes of inserting graphite, i.e., by PG, BAG, CFG and FG. Overall properties were measured, all in correlation with graphite amount and incorporating mode. In stage two, efforts were made to reduce water demand in the Al2O3-MgO castables system. For this purpose, the matrix portion of the castable mixes was extracted and a coaxial double cylinder viscometer was adopted to investigate rheological characteristics of the matrix slurries vs. 4 kinds of deflocculants, through which the best deflocculant and its appropriate amount were found. Efforts were then made to add up to 30% MgO into the castables, using a limited amount of powders (<0.3 mm), the rest being increased in size gradually up to the top size of 4.76 mm. Into the optimized Al2O3-MgO castables graphite was incorporated by PG and BAG, and 4 kinds of antioxidants, Si, SiC, B4C and ZrB2, were added respectively or in combination. Overall properties

  14. Peculiarities of luminescence of nanostructured aluminum oxide with chromium impurity

    International Nuclear Information System (INIS)

    Comparative study of Cr3+ ions photo-, X-ray- and cathodoluminescence in R-lines region in monocrystal and nanostructural aluminium oxide samples with different phase composition is conducted. Peculiarities of chromium impurity inclusion into Al2O3 nanocrystal lattices at high-temperature thermal treatment of Al2O3 and Cr2O3 nanopowders mixture are revealed. It is shown that aluminium oxides nanostructuring can result in formation of complicated aggregate complexes which include anion vacancies and impurity cations. It is marked that the most likely cause of quenching of R-lines luminescence and their broadening at Al2O3 crystal symmetry decrease in α → θ → δ → γ series is anion sublattice disordering while action of crystal field is responsible for levels displacement. It is established that thermal treatment at 1200 deg C doesn't result in complete transformation of nanostructural Al2O3 into α-form as it takes place in macro state

  15. Effect of aluminum oxide on the compressive strength of pellets

    Institute of Scientific and Technical Information of China (English)

    Jian-liang Zhang; Zhen-yang Wang; Xiang-dong Xing; Zheng-jian Liu

    2014-01-01

    Analytical-reagent-grade Al2O3 was added to magnetite ore during the process of pelletizing, and the methods of mercury intru-sion, scanning electron microscopy, and image processing were used to investigate the effect of Al2O3 on the compressive strength of the pellets. The results showed that, as the Al2O3 content increased, the compressive strength of the pellets increased slightly and then decreased gradually. When a small amount of Al2O3 was added to the pellets, the Al2O3 combined with fayalite (2FeO·SiO2) and the aluminosilicate (2FeO·2Al2O3·5SiO2) was generated, which releases some iron oxide and reduces the inhibition of fayalite to the solid phase of consolidation. When Al2O3 increased sequentially, high melting point of Al2O3 particles hinder the oxidation of Fe3O4 and the recrystallization of Fe2O3, making the internal porosity of the pellets increase, which leads to the decrease in compressive strength of the pellets.

  16. Zinc oxide nanoparticles as novel alpha-amylase inhibitors

    Science.gov (United States)

    Dhobale, Sandip; Thite, Trupti; Laware, S. L.; Rode, C. V.; Koppikar, Soumya J.; Ghanekar, Ruchika-Kaul; Kale, S. N.

    2008-11-01

    Amylase inhibitors, also known as starch blockers, contain substances that prevent dietary starches from being absorbed by the body via inhibiting breakdown of complex sugars to simpler ones. In this sense, these materials are projected as having potential applications in diabetes control. In this context, we report on zinc oxide nanoparticles as possible alpha-amylase inhibitors. Zinc oxide nanoparticles have been synthesized using soft-chemistry approach and 1-thioglycerol was used as a surfactant to yield polycrystalline nanoparticles of size ˜18 nm, stabilized in wurtzite structure. Conjugation study and structural characterization have been done using x-ray diffraction technique, Fourier transform infrared spectroscopy, UV-visible spectroscopy, and transmission electron microscopy. Cytotoxicity studies on human fibrosarcoma (HT-1080) and skin carcinoma (A-431) cell lines as well as mouse primary fibroblast cells demonstrate that up to a dose of 20 μg/ml, ZnO nanoparticles are nontoxic to the cells. We report for the first time the alpha-amylase inhibitory activity of ZnO nanoparticles wherein an optimum dose of 20 μg/ml was sufficient to exhibit 49% glucose inhibition at neutral pH and 35 °C temperature. This inhibitory activity was similar to that obtained with acarbose (a standard alpha-amylase inhibitor), thereby projecting ZnO nanoparticles as novel alpha-amylase inhibitors.

  17. Atomic Layer Deposition of Zirconium Oxide on Carbon Nanoparticles

    International Nuclear Information System (INIS)

    In this report we describe preparation of structures containing carbon nanoparticles for potential applications in nonvolatile memories. The carbon nanoparticles were synthesized from 5-methylresorcinol and formaldehyde via base catalysed polycondensation reaction, and were distributed over substrates by dip-coating the substrates into an organic solution. Before deposition of nanoparticles the substrates were covered with 2 nm thick Al2O3 layer grown by atomic layer deposition (ALD) from Al(CH3)3 and O3. After deposition of nanoparticles the samples were coated with ZrO2 films grown from C5H5Zr[N(CH3)2]3 and H2O. Both dielectrics were grown in two-temperature ALD processes starting deposition of Al2O3 at 25 °C and ZrO2 at 200 °C, thereafter completing both processes at a substrate temperature of 300 °C. Deposition of ZrO2 changed the structure of C-nanoparticles, which still remained in a Si/Al2O3/C/ZrO2 structure as a separate layer. Electrical characterization of nanostructures containing Al2O3 as tunnel oxide, C-nanoparticles as charge traps and ZrO2 as control oxide showed hysteretic flat-band voltage shift of about 1V

  18. Preparation of size-controlled tungsten oxide nanoparticles and evaluation of their adsorption performance

    International Nuclear Information System (INIS)

    The present study investigated the effects of particle size on the adsorption performance of tungsten oxide nanoparticles. Nanoparticles 18-73 nm in diameter were prepared by evaporation of bulk tungsten oxide particles using a flame spray process. Annealing plasma-made tungsten oxide nanoparticles produced particles with diameters of 7-19 nm. The mechanism of nanoparticle formation for each synthetic route was examined. The low-cost, solid-fed flame process readily produced highly crystalline tungsten oxide nanoparticles with controllable size and a remarkably high adsorption capability. These nanoparticles are comparable to those prepared using the more expensive plasma process.

  19. Systematic review of potential health risks posed by pharmaceutical, occupational and consumer exposures to metallic and nanoscale aluminum, aluminum oxides, aluminum hydroxide and its soluble salts

    Science.gov (United States)

    Willhite, Calvin C.; Karyakina, Nataliya A.; Yokel, Robert A.; Yenugadhati, Nagarajkumar; Wisniewski, Thomas M.; Arnold, Ian M. F.; Momoli, Franco; Krewski, Daniel

    2016-01-01

    Aluminum (Al) is a ubiquitous substance encountered both naturally (as the third most abundant element) and intentionally (used in water, foods, pharmaceuticals, and vaccines); it is also present in ambient and occupational airborne particulates. Existing data underscore the importance of Al physical and chemical forms in relation to its uptake, accumulation, and systemic bioavailability. The present review represents a systematic examination of the peer-reviewed literature on the adverse health effects of Al materials published since a previous critical evaluation compiled by Krewski et al. (2007). Challenges encountered in carrying out the present review reflected the experimental use of different physical and chemical Al forms, different routes of administration, and different target organs in relation to the magnitude, frequency, and duration of exposure. Wide variations in diet can result in Al intakes that are often higher than the World Health Organization provisional tolerable weekly intake (PTWI), which is based on studies with Al citrate. Comparing daily dietary Al exposures on the basis of “total Al” assumes that gastrointestinal bioavailability for all dietary Al forms is equivalent to that for Al citrate, an approach that requires validation. Current occupational exposure limits (OELs) for identical Al substances vary as much as 15-fold. The toxicity of different Al forms depends in large measure on their physical behavior and relative solubility in water. The toxicity of soluble Al forms depends upon the delivered dose of Al+3 to target tissues. Trivalent Al reacts with water to produce bidentate superoxide coordination spheres [Al(O2)(H2O4)+2 and Al(H2O)6+3] that after complexation with O2•−, generate Al superoxides [Al(O2•)](H2O5)]+2. Semireduced AlO2• radicals deplete mitochondrial Fe and promote generation of H2O2, O2•− and OH•. Thus, it is the Al+3-induced formation of oxygen radicals that accounts for the oxidative damage that

  20. Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles

    Science.gov (United States)

    Bao, Xue-Mei; Cui, Jin-Feng; Sun, Han-Xue; Liang, Wei-Dong; Zhu, Zhao-Qi; An, Jin; Yang, Bao-Ping; La, Pei-Qing; Li, An

    2014-06-01

    A novel method for fabrication of superhydrophobic surfaces was developed by facile coating various metal oxide nanoparticles, including ZnO, Al2O3 and Fe3O4, on various substrates followed by treatment with polydimethylsiloxane (PDMS) via chemical vapor deposition (CVD) method. Using ZnO nanoparticles as a model, the changes in the surface chemical composition and crystalline structures of the metal oxide nanoparticles by PDMS treatment were investigated by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The results show that the combination of the improved surface roughness generated from of the nanoparticles aggregation with the low surface-energy of silicon-coating originated from the thermal pyrolysis of PDMS would be responsible for the surface superhydrophobicity. By a simple dip-coating method, we show that the metal oxide nanoparticles can be easily coated onto the surfaces of various textural and dimensional substrates, including glass slide, paper, fabric or sponge, for preparation of superhydrophobic surfaces for different purpose. The present strategy may provide an inexpensive and new route to surperhydrophobic surfaces, which would be of technological significance for various practical applications especially for separation of oils or organic contaminates from water.

  1. Oxidative stress and toxicity of gold nanoparticles in Mytilus edulis

    International Nuclear Information System (INIS)

    Gold nanoparticles (AuNP) have potential applications in drug delivery, cancer diagnosis and therapy, food industry and environment remediation. However, little is known about their potential toxicity or fate in the environment. Mytilus edulis was exposed in tanks to750 ppb AuNP (average diameter 5.3 ± 1 nm) for 24 h to study in vivo biological effects of nanoparticles. Traditional biomarkers and an affinity procedure selective for thiol-containing proteins followed by two-dimensional electrophoresis (2DE) separations were used to study toxicity and oxidative stress responses. Results were compared to those obtained for treatment with cadmium chloride, a well known pro-oxidant. M. edulis mainly accumulated AuNP in digestive gland which also showed higher lipid peroxidation. One-dimensional SDS/PAGE (1DE) and 2DE analysis of digestive gland samples revealed decreased thiol-containing proteins for AuNP. Lysosomal membrane stability measured in haemolymph gave lower values for neutral red retention time (NRRT) in both treatments but was greater in AuNP. Oxidative stress occurred within 24 h of AuNP exposure in M. edulis. Previously we showed that larger diameter AuNP caused modest effects, indicating that nanoparticle size is a key factor in biological responses to nanoparticles. This study suggests that M. edulis is a suitable model animal for environmental toxicology studies of nanoparticles.

  2. Oxidative stress and toxicity of gold nanoparticles in Mytilus edulis

    Energy Technology Data Exchange (ETDEWEB)

    Tedesco, Sara [Environmental Research Institute of University College Cork, Cork (Ireland); Doyle, Hugh [Tyndall National Institute, Cork (Ireland); Blasco, Julian [Consejo Superior de Investigaciones Cientificas (CSIC), Marine Science Institute of Andalusia, Cadiz (Spain); Redmond, Gareth [Tyndall National Institute, Cork (Ireland); Sheehan, David, E-mail: d.sheehan@ucc.ie [Environmental Research Institute of University College Cork, Cork (Ireland)

    2010-10-15

    Gold nanoparticles (AuNP) have potential applications in drug delivery, cancer diagnosis and therapy, food industry and environment remediation. However, little is known about their potential toxicity or fate in the environment. Mytilus edulis was exposed in tanks to750 ppb AuNP (average diameter 5.3 {+-} 1 nm) for 24 h to study in vivo biological effects of nanoparticles. Traditional biomarkers and an affinity procedure selective for thiol-containing proteins followed by two-dimensional electrophoresis (2DE) separations were used to study toxicity and oxidative stress responses. Results were compared to those obtained for treatment with cadmium chloride, a well known pro-oxidant. M. edulis mainly accumulated AuNP in digestive gland which also showed higher lipid peroxidation. One-dimensional SDS/PAGE (1DE) and 2DE analysis of digestive gland samples revealed decreased thiol-containing proteins for AuNP. Lysosomal membrane stability measured in haemolymph gave lower values for neutral red retention time (NRRT) in both treatments but was greater in AuNP. Oxidative stress occurred within 24 h of AuNP exposure in M. edulis. Previously we showed that larger diameter AuNP caused modest effects, indicating that nanoparticle size is a key factor in biological responses to nanoparticles. This study suggests that M. edulis is a suitable model animal for environmental toxicology studies of nanoparticles.

  3. Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Xue-Mei; Cui, Jin-Feng; Sun, Han-Xue; Liang, Wei-Dong; Zhu, Zhao-Qi; An, Jin; Yang, Bao-Ping; La, Pei-Qing; Li, An, E-mail: lian2010@lut.cn

    2014-06-01

    A novel method for fabrication of superhydrophobic surfaces was developed by facile coating various metal oxide nanoparticles, including ZnO, Al{sub 2}O{sub 3} and Fe{sub 3}O{sub 4}, on various substrates followed by treatment with polydimethylsiloxane (PDMS) via chemical vapor deposition (CVD) method. Using ZnO nanoparticles as a model, the changes in the surface chemical composition and crystalline structures of the metal oxide nanoparticles by PDMS treatment were investigated by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The results show that the combination of the improved surface roughness generated from of the nanoparticles aggregation with the low surface-energy of silicon-coating originated from the thermal pyrolysis of PDMS would be responsible for the surface superhydrophobicity. By a simple dip-coating method, we show that the metal oxide nanoparticles can be easily coated onto the surfaces of various textural and dimensional substrates, including glass slide, paper, fabric or sponge, for preparation of superhydrophobic surfaces for different purpose. The present strategy may provide an inexpensive and new route to surperhydrophobic surfaces, which would be of technological significance for various practical applications especially for separation of oils or organic contaminates from water.

  4. Reaction behavior between the oxide film of LY12 aluminum alloy and the flux

    Institute of Scientific and Technical Information of China (English)

    薛松柏; 董健; 吕晓春; 顾文华

    2004-01-01

    In this paper, the brazing mechanism of LY12 aluminum alloy at middle range temperature was presented. The CsF-AlF3 non-corrosive flux was utilized to remove the complex oxide film on the surface of LY12 aluminum alloy. The results revealed that the oxide film was removed by the improved CsF-AlF3 flux accompanied with the occurrence of reaction as well as dissolution and the compounds CsF played an important role to remove the oxide film. Actually, the high activity of flux, say, the ability to remove the oxide film, was due to the presence of the compounds, such as NH4F,NH4AlF4 and composite molten salt. The production of HF was the key issue to accelerate the reaction and enhance to eliminate the oxide film by dissolution. It was found that the rare earth element La at small percentage was not enriched at the interface. Moreover, the rare earth fluoride enhanced the dissolution behavior.

  5. Multifunctional Iron Oxide Nanoparticles for Diagnostics, Therapy and Macromolecule Delivery

    OpenAIRE

    Yen, Swee Kuan; Padmanabhan, Parasuraman; Selvan, Subramanian Tamil

    2013-01-01

    In recent years, multifunctional nanoparticles (NPs) consisting of either metal (e.g. Au), or magnetic NP (e.g. iron oxide) with other fluorescent components such as quantum dots (QDs) or organic dyes have been emerging as versatile candidate systems for cancer diagnosis, therapy, and macromolecule delivery such as micro ribonucleic acid (microRNA). This review intends to highlight the recent advances in the synthesis and application of multifunctional NPs (mainly iron oxide) in theranostics,...

  6. Antioxidant Cerium Oxide Nanoparticles in Biology and Medicine

    OpenAIRE

    Nelson, Bryant C.; Monique E. Johnson; Walker, Marlon L.; Riley, Kathryn R.; Christopher M. Sims

    2016-01-01

    Previously, catalytic cerium oxide nanoparticles (CNPs, nanoceria, CeO2-x NPs) have been widely utilized for chemical mechanical planarization in the semiconductor industry and for reducing harmful emissions and improving fuel combustion efficiency in the automobile industry. Researchers are now harnessing the catalytic repertoire of CNPs to develop potential new treatment modalities for both oxidative- and nitrosative-stress induced disorders and diseases. In order to reach the point where o...

  7. Iron oxide nanoparticles in different modifications for antimicrobial phototherapy

    Science.gov (United States)

    Tuchina, Elena S.; Kozina, Kristina V.; Shelest, Nikita A.; Kochubey, Vyacheslav I.; Tuchin, Valery V.

    2014-03-01

    The main goal of this study was to investigate the sensitivity of microorganisms to combined action of blue light and iron oxide nanoparticles. Two strains of Staphylococcus aureus - methicillin-sensitive and meticillin-resistant were used. As a blue light source LED with spectral maximum at 405 nm was taken. The light exposure was ranged from 5 to 30 min. The Fe2O3 (diameter ˜27 nm), Fe3O4 nanoparticles (diameter ˜19 nm), and composite Fe2O3/TiO2 nanoparticles (diameter ˜100 nm) were synthesized. It was shown that irradiation by blue light caused from 20% to 88% decrease in the number of microorganisms treated with nanoparticles. Morphological changes in bacterial cells after phototreatment were analyzed using scanning electron microscope.

  8. Antibacterial effect of zinc oxide nanoparticles combined with ultrasound

    International Nuclear Information System (INIS)

    Using Staphylococcus aureus (S. aureus), the present study investigated the antibacterial effect of ZnO nanoparticles both in the absence and presence of ultrasound stimulation. While the antibacterial effect of control nanoparticle chemistries (Al2O3) alone was either weak or unobservable under the conditions tested, the antibacterial effect of ZnO alone was significant, providing over a four log reduction (equivalent to antibiotics) compared to no treatment after just 8 h. The antibacterial effect was enhanced as ZnO particle diameter decreased. Specifically, when testing the antibacterial effect against bacteria populations relevant to infection, a 500 μg ml−1 dose of zinc oxide nanoparticles with a diameter of 20 nm reduced S. aureus populations by four orders of magnitude after 8 and 24 h, compared to control groups with no nanoparticles. This was accomplished without the use of antibiotics, to which bacteria are developing a resistance anyway. The addition of ultrasound stimulation further reduced the number of viable colony-forming units present in a planktonic cell suspension by 76% compared to nanoparticles alone. Lastly, this study provided a mechanism for how ZnO nanoparticles in the presence of ultrasound decrease bacteria functions by demonstrating greater hydrogen peroxide generation by S. aureus compared to controls. These results indicated that small-diameter ZnO nanoparticles exhibited strong antibacterial properties that can be additionally enhanced in the presence of ultrasound and, thus, should be further studied for a wide range of medical device anti-infection applications. (paper)

  9. Evaluation of cytotoxicity of polypyrrole nanoparticles synthesized by oxidative polymerization

    International Nuclear Information System (INIS)

    Highlights: ► Polypyrrole nanoparticles synthesized by environmentally friendly polymerization at high concentrations are cytotoxic. ► Primary mouse embryonic fibroblast, mouse hepatoma and human T lymphocyte Jurkat cell lines were treated by Ppy nanoparticles. ► Polypyrrole nanoparticles at high concentrations inhibit cell proliferation. -- Abstract: Polypyrrole (Ppy) is known as biocompatible material, which is used in some diverse biomedical applications and seeming to be a very promising for advanced biotechnological applications. In order to increase our understanding about biocompatibility of Ppy, in this study pure Ppy nanoparticles (Ppy-NPs) of fixed size and morphology were prepared by one-step oxidative polymerization and their cyto-compatibility was evaluated. The impact of different concentration of Ppy nanoparticles on primary mouse embryonic fibroblasts (MEF), mouse hepatoma cell line (MH-22A), and human T lymphocyte Jurkat cell line was investigated. Cell morphology, viability/proliferation after the treatment by Ppy nanoparticles was evaluated. Obtained results showed that Ppy nanoparticles at low concentrations are biocompatible, while at high concentrations they became cytotoxic for Jurkat, MEF and MH-22A cells, and it was found that cytotoxic effect is dose-dependent

  10. Evaluation of cytotoxicity of polypyrrole nanoparticles synthesized by oxidative polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Vaitkuviene, Aida [Department of Physical Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Department of Stem Cell Biology, State Research Institute Center for Innovative Medicine, Zygimantu 9, LT-01102 Vilnius (Lithuania); Kaseta, Vytautas [Department of Stem Cell Biology, State Research Institute Center for Innovative Medicine, Zygimantu 9, LT-01102 Vilnius (Lithuania); Voronovic, Jaroslav [Department of Physical Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Ramanauskaite, Giedre; Biziuleviciene, Gene [Department of Stem Cell Biology, State Research Institute Center for Innovative Medicine, Zygimantu 9, LT-01102 Vilnius (Lithuania); Ramanaviciene, Almira [NanoTechnas–Center of Nanotechnology and Material Science at Department of Analytical and Environmental Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, 03225 Vilnius (Lithuania); Ramanavicius, Arunas, E-mail: Arunas.Ramanavicius@chf.vu.lt [Department of Physical Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Laboratory of BioNanoTechnology, Department of Materials Science and Electronics, Institute of Semiconductor Physics, State Scientific Research Institute Centre for Physical Sciences and Technology, A. Gostauto 11, LT-01108 Vilnius (Lithuania)

    2013-04-15

    Highlights: ► Polypyrrole nanoparticles synthesized by environmentally friendly polymerization at high concentrations are cytotoxic. ► Primary mouse embryonic fibroblast, mouse hepatoma and human T lymphocyte Jurkat cell lines were treated by Ppy nanoparticles. ► Polypyrrole nanoparticles at high concentrations inhibit cell proliferation. -- Abstract: Polypyrrole (Ppy) is known as biocompatible material, which is used in some diverse biomedical applications and seeming to be a very promising for advanced biotechnological applications. In order to increase our understanding about biocompatibility of Ppy, in this study pure Ppy nanoparticles (Ppy-NPs) of fixed size and morphology were prepared by one-step oxidative polymerization and their cyto-compatibility was evaluated. The impact of different concentration of Ppy nanoparticles on primary mouse embryonic fibroblasts (MEF), mouse hepatoma cell line (MH-22A), and human T lymphocyte Jurkat cell line was investigated. Cell morphology, viability/proliferation after the treatment by Ppy nanoparticles was evaluated. Obtained results showed that Ppy nanoparticles at low concentrations are biocompatible, while at high concentrations they became cytotoxic for Jurkat, MEF and MH-22A cells, and it was found that cytotoxic effect is dose-dependent.

  11. External quantum efficiency and photovoltaic performance of silicon cells deposited with aluminum, indium, and silver nanoparticles

    Science.gov (United States)

    Ho, Wen-Jeng; Hu, Chia-Hua; Yeh, Chien-Wu; Lee, Yi-Yu

    2016-08-01

    In this study, the plasmonic light scattering of aluminum (Al), indium (In), and sliver (Ag) nanoparticles (NPs) deposited on silicon solar cells was demonstrated. For comparison, the dimensions of all NPs were maintained at 17–25 nm with a coverage of approximately 30–40% through the control of film deposition and thermal annealing conditions. Absorbance and surface plasmon Raman scattering were used to examine the different localized surface plasmon resonances (LSPRs) of the proposed NPs. Optical reflectance, external quantum efficiency (EQE) response, and photovoltaic current density–voltage characteristics under AM 1.5G illumination were used to confirm the contribution of the plasmonic light scattering of the NPs. The conversion efficiencies of the solar cells with Al, In, and Ag NPs increased 1.21-, 1.23-, and 1.17-fold, respectively, compared with that of the reference bare Si solar cell. The EQE response and photovoltaic performance revealed that Al and In NPs produced broadband plasmonic light scattering and increased efficiency, far exceeding the results obtained using Ag NPs.

  12. Magnetic properties of ultrasmall iron-oxide nanoparticles

    International Nuclear Information System (INIS)

    Highlights: • The ultrasmall iron oxide nanoparticles in organic fluid were synthesized with diameter d ∼ 3 nm. • Very low blocking temperature, TB = 10 K, is determined in accordance with size. • Nanoparticles in fluid are noninteracting, drying brings interaction between nanoparticles. • High influence of surface on the magnetic properties. • High magnetic anisotropy due to surface anisotropy, ∼ 106 erg/cm3, 100 times higher than in bulk. - Abstract: The work presents structural and magnetic properties of ultrasmall magnetic nanoparticles consisting of inorganic iron oxide core and organic ester shell, dispersed in an organic fluid, synthesized via polyol route. The structure analysis shows that nanoparticles are crystalline, less than 3 nm in size, mutually clearly separated. The magnetic properties are in accordance with the size of the nanoparticles and do not indicate interparticle interactions. The particles show pure superparamagnetic behavior with very low blocking temperature. ZFCFC bifurcation and ac susceptibility peaks are at temperatures TB < 12 K. The properties of fluid were compared with dried powder sample. Drying of fluid brings about interactions between the magnetic nanoparticles that considerably affect spin dynamics of the particles. The surface of nanoparticles has a significant influence on their behavior. The Mössbauer parameters indicate existence of γ-Fe2O3 core and non-stoichiometric surface layer. Magnetic field dependent magnetization analysis suggests smaller apparent size of the particles d0 = 0.56 nm. High magnetic anisotropy due to surface layer anisotropy was measured to be of the order 106 erg/cm3 that is two orders of magnitude higher than that in bulk material

  13. Application of diffusion barriers to the refractory fibers of tungsten, columbium, carbon and aluminum oxide

    Science.gov (United States)

    Douglas, F. C.; Paradis, E. L.; Veltri, R. D.

    1973-01-01

    A radio frequency powered ion-plating system was used to plate protective layers of refractory oxides and carbide onto high strength fiber substrates. Subsequent overplating of these combinations with nickel and titanium was made to determine the effectiveness of such barrier layers in preventing diffusion of the overcoat metal into the fibers with consequent loss of fiber strength. Four substrates, five coatings, and two metal matrix materials were employed for a total of forty material combinations. The substrates were tungsten, niobium, NASA-Hough carbon, and Tyco sapphire. The diffusion-barrier coatings were aluminum oxide, yttrium oxide, titanium carbide, tungsten carbide with 14% cobalt addition, and zirconium carbide. The metal matrix materials were IN 600 nickel and Ti 6/4 titanium. Adhesion of the coatings to all substrates was good except for the NASA-Hough carbon, where flaking off of the oxide coatings in particular was observed.

  14. High performance In2O3 thin film transistors using chemically derived aluminum oxide dielectric

    KAUST Repository

    Nayak, Pradipta K.

    2013-07-18

    We report high performance solution-deposited indium oxide thin film transistors with field-effect mobility of 127 cm2/Vs and an Ion/Ioff ratio of 106. This excellent performance is achieved by controlling the hydroxyl group content in chemically derived aluminum oxide (AlOx) thin-film dielectrics. The AlOx films annealed in the temperature range of 250–350 °C showed higher amount of Al-OH groups compared to the films annealed at 500 °C, and correspondingly higher mobility. It is proposed that the presence of Al-OH groups at the AlOx surface facilitates unintentional Al-doping and efficient oxidation of the indium oxide channel layer, leading to improved device performance.

  15. Coverage and disruption of phospholipid membranes by oxide nanoparticles

    NARCIS (Netherlands)

    Pera, H.; Nolte, T.M.; Leermakers, F.A.M.; Kleijn, J.M.

    2014-01-01

    We studied the interactions of silica and titanium dioxide nanoparticles with phospholipid membranes and show how electrostatics plays an important role. For this, we systematically varied the charge density of both the membranes by changing their lipid composition and the oxide particles by changin

  16. Core-shell iron-iron oxide nanoparticles

    DEFF Research Database (Denmark)

    Kuhn, Luise Theil; Bojesen, A.; Timmermann, L.; Fauth, K.; Goering, E.; Johnson, Erik; Nielsen, Martin Meedom; Mørup, Steen

    We present studies of the magnetic properties of core-shell iron-iron oxide nanoparticles. By combining Mossbauer and X-ray absorption spectroscopy we have been able to measure the change from a Fe3O4-like to a gamma-Fe2O3-like composition from the interface to the surface. Furthermore, we have...

  17. Core-shell iron-iron oxide nanoparticles

    DEFF Research Database (Denmark)

    Kuhn, Luise Theil; Bojesen, A.; Timmermann, L.;

    2004-01-01

    We present studies of the magnetic properties of core-shell iron-iron oxide nanoparticles. By combining Mossbauer and X-ray absorption spectroscopy we have been able to measure the change from a Fe3O4-like to a gamma-Fe2O3-like composition from the interface to the surface. Furthermore, we have...

  18. Identification of Spinel Iron Oxide Nanoparticles by 57Fe NMR

    Directory of Open Access Journals (Sweden)

    SangGap Lee

    2011-12-01

    Full Text Available We have synthesized and studied monodisperse iron oxide nanoparticles of smaller than 10 nm to identify between the two spinel phases, magnetite and maghemite. It is shown that 57Fe NMR spectroscopy is a promising tool for distinguishing between the two phases.

  19. The influence of titanium and iron oxides on the coloring and friability of the blue fired aluminum oxide as an abrasive material

    OpenAIRE

    E. R. Passos; J. A. Rodrigues

    2016-01-01

    Abstract The quality of abrasive grains is crucial to increase the lifespan of roughing, polishing and cutting tools. The purpose of the work herein was to evaluate the variables of the blue fired aluminum oxide heat treatment process. This heat treatment process improves the physical properties of the brown fused aluminum oxide and results in a blue coloring, which uniquely identifies it within the abrasives industry. The work herein includes information beginning with the electro-fusion pro...

  20. A theoretical framework for predicting the oxidative stress potential of oxide nanoparticles.

    Science.gov (United States)

    Burello, Enrico; Worth, Andrew P

    2011-06-01

    In this paper we propose a theoretical model that predicts the oxidative stress potential of oxide nanoparticles by looking at the ability of these materials to perturb the intracellular redox state. The model uses reactivity descriptors to build the energy band structure of oxide nanoparticles, assuming a particle diameter larger than 20-30 nm and no surface states in the band gap, and predicts their ability to induce an oxidative stress by comparing the redox potentials of relevant intracellular reactions with the oxides' energy structure. Nanoparticles displaying band energy values comparable with redox potentials of antioxidants or radical formation reactions have the ability to cause an oxidative stress and a cytotoxic response in vitro. We discuss the model's predictions for six relevant oxide nanoparticles (TiO(2), CuO, ZnO, FeO, Fe(2)O(3), Fe(3)O(4)) with literature in vitro studies and calculate the energy structure for 64 additional oxide nanomaterials. Such a framework would guide the development of more rational and efficient screening strategies avoiding random or exhaustive testing of new nanomaterials. PMID:21609138

  1. Synthesis and structure analysis of aluminum doped zinc oxide powders

    Institute of Scientific and Technical Information of China (English)

    NIE DengPan; XUE Tao; ZHANG Yu; LI XiangJun

    2008-01-01

    Hexagonal Al-doped zinc oxide (ZnO) powders with a nominal composition of Zn1-xAlxO (0≤x≤0.028) were synthesized by the co-precipitation method. The contents of the Al element in the samples were measured by the inductively coupled plasma-optical emission spectroscopy (ICP-OES) technique. The structures of the Zn1-xAlxO (0≤x≤0.028) compounds calcined at 1000 and 1200℃ have been deter-mined using the Rietveld full-profile analysis method. Rietveld refinements of the diffraction data indi-cated that the addition of Al initially has a considerably positive effect on the decreasing of the lattice parameters a and c of Zn1-xAlxO, but the effect becomes very slight and even negative with the further increase of the Al content. The solid solubility limit of Al in ZnO (mole fraction y) is 2.21%, resulting in Zn0.978Al0.22O. It seems that when the Al content is excessive, Al prefers to form a ZnAl2O4 compound with ZnO, but not to incorporate into the ZnO lattice to occupy the Zn2+ cites. Two phases, [ZnO] (or Al-doped ZnO) and [ZnAl2O4], are obviously segregated in Zn1-xAlxO while the value of x is larger than 0.024. The UV-Vis absorption spectra show that the Al-doped ZnO exhibits a red-shift in the absorption edge without reduced transmission compared with pure ZnO, which also confirms that Al ions enter the ZnO lattice and form a Zn1-xAlxO solid solution.

  2. Synthesis and structure analysis of aluminum doped zinc oxide powders

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Hexagonal Al-doped zinc oxide (ZnO) powders with a nominal composition of Zn1-xAlxO (0≤x≤0.028) were synthesized by the co-precipitation method. The contents of the Al element in the samples were measured by the inductively coupled plasma-optical emission spectroscopy (ICP-OES) technique. The structures of the Zn1-xAlxO (0≤x≤0.028) compounds calcined at 1000 and 1200℃ have been deter- mined using the Rietveld full-profile analysis method. Rietveld refinements of the diffraction data indi- cated that the addition of Al initially has a considerably positive effect on the decreasing of the lattice parameters a and c of Zn1-xAlxO, but the effect becomes very slight and even negative with the further increase of the Al content. The solid solubility limit of Al in ZnO (mole fraction y) is 2.2l%, resulting in Zn0.978Al0.22O. It seems that when the Al content is excessive, Al prefers to form a ZnAl2O4 compound with ZnO, but not to incorporate into the ZnO lattice to occupy the Zn2+ cites. Two phases, [ZnO] (or Al-doped ZnO) and [ZnAl2O4], are obviously segregated in Zn1-xAlxO while the value of x is larger than 0.024. The UV-Vis absorption spectra show that the Al-doped ZnO exhibits a red-shift in the absorption edge without reduced transmission compared with pure ZnO, which also confirms that Al ions enter the ZnO lattice and form a Zn1-xAlxO solid solution.

  3. A Prediction Study of Aluminum Alloy Oxidation of the Fuel Cladding in Jordan Research and Training Reactor

    International Nuclear Information System (INIS)

    U3Si2-Al dispersion fuel with Al cladding will be used for Jordan Research and Training Reactor (JRTR). Aluminum alloy cladding experiences the oxidation layer growth on the surface during the reactor operation. The formation of oxides on the cladding affects fuel performance by increasing fuel temperature. According to the current JRTR fuel management scheme and operation strategy for 5 MW power, a fresh fuel is discharged after 900 effective full power days (EFPD) with 18 cycles of 50 days loading. For the proper prediction of the aluminum oxide thickness of fuel cladding during the long residence time, a reliable model is needed. In this work, several oxide thickness prediction models are compared with the measured data from in-pile test by RERTR program. Moreover, specific parametric studies and a preliminary prediction of the aluminum alloy oxidation using the latest model are performed for JRTR fuel

  4. Method of making highly porous, stable aluminum oxides doped with silicon

    Energy Technology Data Exchange (ETDEWEB)

    Khosravi-Mardkhe, Maryam; Woodfield, Brian F.; Bartholomew, Calvin H.; Huang, Baiyu

    2016-03-22

    The present invention relates to a method for making high surface area and large pore volume thermally stable silica-doped alumina (aluminum oxide) catalyst support and ceramic materials. The ability of the silica-alumina to withstand high temperatures in presence or absence of water and prevent sintering allows it to maintain good activity over a long period of time in catalytic reactions. The method of preparing such materials includes adding organic silicon reagents to an organic aluminum salt such as an alkoxide in a controlled quantity as a doping agent in a solid state, solvent deficient reaction followed by calcination. Alternatively, the organic silicon compound may be added after calcination of the alumina, followed by another calcination step. This method is inexpensive and simple. The alumina catalyst support material prepared by the subject method maintains high pore volumes, pore diameters and surface areas at very high temperatures and in the presence of steam.

  5. Sound Absorption Characteristics of Aluminum Foams Treated by Plasma Electrolytic Oxidation

    Directory of Open Access Journals (Sweden)

    Wei Jin

    2015-11-01

    Full Text Available Open-celled aluminum foams with different pore sizes were fabricated. A plasma electrolytic oxidation (PEO treatment was applied on the aluminum foams to create a layer of ceramic coating. The sound absorption coefficients of the foams were measured by an impedance tube and they were calculated by a transfer function method. The experimental results show that the sound absorption coefficient of the foam increases gradually with the decrease of pore size. Additionally, when the porosity of the foam increases, the sound absorption coefficient also increases. The PEO coating surface is rough and porous, which is beneficial for improvement in sound absorption. After PEO treatment, the maximum sound absorption of the foam is improved to some extent.

  6. Electromechanical Breakdown of Barrier-Type Anodized Aluminum Oxide Thin Films Under High Electric Field Conditions

    Science.gov (United States)

    Chen, Jianwen; Yao, Manwen; Yao, Xi

    2016-02-01

    Barrier-type anodized aluminum oxide (AAO) thin films were formed on a polished aluminum substrate via electrochemical anodization in 0.1 mol/L aqueous solution of ammonium pentaborate. Electromechanical breakdown occurred under high electric field conditions as a result of the accumulation of mechanical stress in the film-substrate system by subjecting it to rapid thermal treatment. Before the breakdown event, the electricity of the films was transported in a highly nonlinear way. Immediately after the breakdown event, dramatic cracking of the films occurred, and the cracks expanded quickly to form a mesh-like dendrite network. The breakdown strength was significantly reduced because of the electromechanical coupling effect, and was only 34% of the self-healing breakdown strength of the AAO film.

  7. Study on wear behavior of plasma electrolytic oxidation coatings on aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    CUI Shihai; HAN Jianmin; LI Weijing; KANG Suk-Bong; LEE Jung-Moo

    2006-01-01

    Thick and hard ceramic coatings were fabricated on A356 aluminum alloy by using plasma electrolytic oxidation(PEO) technique.The microstructure and phase composition of the PEO coatings were examined by using SEM and XRD method.It is found that the PEO coatings are mainly composed of crystalline α-Al2O3 and mullite.The dry sliding wear test of PEO coatings were carried out on a ring-on-ring wear machine.Results shows that there is hardly no wear loss of polished PEO coatings while the wear rate of uncoated aluminum alloy is 4.3×10-5 mm3·(N·m)-1 at a speed of 0.52 m·s-1 and a load of 40 N.

  8. Ablation characteristics of aluminum oxide and nitride ceramics during femtosecond laser micromachining

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Hoon [School of Information and Mechatronics, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong Buk-gu, Gwangju 500-712 (Korea, Republic of); Sohn, Ik-Bu [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong Buk-gu, Gwangju 500-712 (Korea, Republic of); Jeong, Sungho, E-mail: shjeong@gist.ac.kr [School of Information and Mechatronics, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2009-09-30

    Femtosecond laser ablation of aluminum oxide (Al{sub 2}O{sub 3}) and aluminum nitride (AlN) ceramics was performed under normal atmospheric conditions ({lambda} = 785 nm, {tau}{sub p} = 185 fs, repetition rate = 1 kHz), and threshold laser fluencies for single- and multi-pulse ablation were determined. The ablation characteristics of the two ceramics showed similar trends except for surface morphologies, which revealed virtually no melting in Al{sub 2}O{sub 3} but clear evidence of melting for AlN. Based on subsequent X-ray photoelectron spectroscopy (XPS) analyses, the chemistry of these ceramics appeared to remain the same before and after femtosecond laser ablation.

  9. Colloidal infrared reflective and transparent conductive aluminum-doped zinc oxide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Buonsanti, Raffaella; Milliron, Delia J

    2015-02-24

    The present invention provides a method of preparing aluminum-doped zinc oxide (AZO) nanocrystals. In an exemplary embodiment, the method includes (1) injecting a precursor mixture of a zinc precursor, an aluminum precursor, an amine, and a fatty acid in a solution of a vicinal diol in a non-coordinating solvent, thereby resulting in a reaction mixture, (2) precipitating the nanocrystals from the reaction mixture, thereby resulting in a final precipitate, and (3) dissolving the final precipitate in an apolar solvent. The present invention also provides a dispersion. In an exemplary embodiment, the dispersion includes (1) nanocrystals that are well separated from each other, where the nanocrystals are coated with surfactants and (2) an apolar solvent where the nanocrystals are suspended in the apolar solvent. The present invention also provides a film. In an exemplary embodiment, the film includes (1) a substrate and (2) nanocrystals that are evenly distributed on the substrate.

  10. CHEMISTRY OF SO2 AND DESOX PROCESSES ON OXIDE NANOPARTICLES.

    Energy Technology Data Exchange (ETDEWEB)

    RODRIGUEZ, J.A.

    2006-06-30

    On bulk stoichiometric oxides, SO{sub 2} mainly reacts with the O centers to form SO{sub 3} or SO{sub 4} species that decompose at elevated temperatures. Adsorption on the metal cations occurs below 300 K and does not lead to cleavage of the S-O bonds. In bulk oxides, the occupied cation bands are too stable for effective bonding interactions with the LUMO of SO{sub 2}. The effects of quantum confinement on the electronic properties of oxide nanoparticles and the structural defects that usually accompany these systems in general favor the bonding and dissociation of SO{sub 2}. Thus, nanoparticles of MgO, CaO, SrO, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3} and CeO{sub 2} are all more efficient for sequestering SO{sub 2} than the corresponding bulk oxides. Structural imperfections in pure or metal-doped ceria nanoparticles accelerate the reduction of SO{sub 2} by CO by facilitating the formation and migration of O vacancies in the oxide surface.

  11. Progress in electrochemical synthesis of magnetic iron oxide nanoparticles

    International Nuclear Information System (INIS)

    Recently, magnetic iron oxide particles have been emerged as significant nanomaterials due to its extensive range of application in various fields. In this regard, synthesis of iron oxide nanoparticles with desirable properties and high potential applications are greatly demanded. Therefore, investigation on different iron oxide phases and their magnetic properties along with various commonly used synthetic techniques are remarked and thoroughly described in this review. Electrochemical synthesis as a newfound method with unique advantages is elaborated, followed by design approaches and key parameters to control the properties of the iron oxide nanoparticles. Additionally, since the dispersion of iron oxide nanoparticles is as important as its preparation, surface modification issue has been a serious challenge which is comprehensively discussed using different surfactants. Despite the advantages of the electrochemical synthesis method, this technique has been poorly studied and requires deep investigations on effectual parameters such as current density, pH, electrolyte concentration etc. - Highlights: • IONPs are applied in chemical industries, medicine, magnetic storage etc. • Electrochemical synthesis (EC) is convenient, eco-friendly, selective and low-cost. • EC key factors are current density, pH, electrolyte concentration, electrode type. • Organic, inorganic and biological materials can be used to modify IONPs’ surface. • The physicochemical properties of IONPs can be controlled by adding surfactants

  12. Progress in electrochemical synthesis of magnetic iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ramimoghadam, Donya; Bagheri, Samira, E-mail: samira_bagheri@um.edu.my; Hamid, Sharifah Bee Abd

    2014-11-15

    Recently, magnetic iron oxide particles have been emerged as significant nanomaterials due to its extensive range of application in various fields. In this regard, synthesis of iron oxide nanoparticles with desirable properties and high potential applications are greatly demanded. Therefore, investigation on different iron oxide phases and their magnetic properties along with various commonly used synthetic techniques are remarked and thoroughly described in this review. Electrochemical synthesis as a newfound method with unique advantages is elaborated, followed by design approaches and key parameters to control the properties of the iron oxide nanoparticles. Additionally, since the dispersion of iron oxide nanoparticles is as important as its preparation, surface modification issue has been a serious challenge which is comprehensively discussed using different surfactants. Despite the advantages of the electrochemical synthesis method, this technique has been poorly studied and requires deep investigations on effectual parameters such as current density, pH, electrolyte concentration etc. - Highlights: • IONPs are applied in chemical industries, medicine, magnetic storage etc. • Electrochemical synthesis (EC) is convenient, eco-friendly, selective and low-cost. • EC key factors are current density, pH, electrolyte concentration, electrode type. • Organic, inorganic and biological materials can be used to modify IONPs’ surface. • The physicochemical properties of IONPs can be controlled by adding surfactants.

  13. Targeted magnetic iron oxide nanoparticles for tumor imaging and therapy

    Directory of Open Access Journals (Sweden)

    Xiang-Hong Peng

    2008-10-01

    Full Text Available Xiang-Hong Peng1,4, Ximei Qian2,4, Hui Mao3,4, Andrew Y Wang5, Zhuo (Georgia Chen1,4, Shuming Nie2,4, Dong M Shin1,4*1Department of Medical Oncology/Hematology; 2Department of Biomedical Engineering; 3Department of Radiology; 4Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA; 5Ocean Nanotech, LLC, Fayetteville, AR, USAAbstract: Magnetic iron oxide (IO nanoparticles with a long blood retention time, biodegradability and low toxicity have emerged as one of the primary nanomaterials for biomedical applications in vitro and in vivo. IO nanoparticles have a large surface area and can be engineered to provide a large number of functional groups for cross-linking to tumor-targeting ligands such as monoclonal antibodies, peptides, or small molecules for diagnostic imaging or delivery of therapeutic agents. IO nanoparticles possess unique paramagnetic properties, which generate significant susceptibility effects resulting in strong T2 and T*2 contrast, as well as T1 effects at very low concentrations for magnetic resonance imaging (MRI, which is widely used for clinical oncology imaging. We review recent advances in the development of targeted IO nanoparticles for tumor imaging and therapy.Keywords: iron oxide nanoparticles, tumor imaging, MRI, therapy

  14. Copper Nanoparticles for Printed Electronics: Routes Towards Achieving Oxidation Stability

    Directory of Open Access Journals (Sweden)

    Shlomo Magdassi

    2010-09-01

    Full Text Available In the past few years, the synthesis of Cu nanoparticles has attracted much attention because of its huge potential for replacing expensive nano silver inks utilized in conductive printing. A major problem in utilizing these copper nanoparticles is their inherent tendency to oxidize in ambient conditions. Recently, there have been several reports presenting various approaches which demonstrate that copper nanoparticles can resist oxidation under ambient conditions, if they are coated by a proper protective layer. This layer may consist of an organic polymer, alkene chains, amorphous carbon or graphenes, or inorganic materials such as silica, or an inert metal. Such coated copper nanoparticles enable achieving high conductivities by direct printing of conductive patterns. These approaches open new possibilities in printed electronics, for example by using copper based inkjet inks to form various devices such as solar cells, Radio Frequency Identification (RFID tags, and electroluminescence devices. This paper provides a review on the synthesis of copper nanoparticles, mainly by wet chemistry routes, and their utilization in printed electronics.

  15. Mercury removal in wastewater by iron oxide nanoparticles

    Science.gov (United States)

    Vélez, E.; Campillo, G. E.; Morales, G.; Hincapié, C.; Osorio, J.; Arnache, O.; Uribe, J. I.; Jaramillo, F.

    2016-02-01

    Mercury is one of the persistent pollutants in wastewater; it is becoming a severe environmental and public health problem, this is why nowadays its removal is an obligation. Iron oxide nanoparticles are receiving much attention due to their properties, such as: great biocompatibility, ease of separation, high relation of surface-area to volume, surface modifiability, reusability, excellent magnetic properties and relative low cost. In this experiment, Fe3O4 and γ-Fe2O3 nanoparticles were synthesized using iron salts and NaOH as precipitation agents, and Aloe Vera as stabilizing agent; then these nanoparticles were characterized by three different measurements: first, using a Zetasizer Nano ZS for their size estimation, secondly UV-visible spectroscopy which showed the existence of resonance of plasmon at λmax∼360 nm, and lastly by Scanning Electron Microscopy (SEM) to determine nanoparticles form. The results of this characterization showed that the obtained Iron oxides nanoparticles have a narrow size distribution (∼100nm). Mercury removal of 70% approximately was confirmed by atomic absorption spectroscopy measurements.

  16. Nanoparticle Toxicity Mechanisms: Oxidative Stress and Inflammation

    Science.gov (United States)

    L'Azou, Béatrice; Marano, Francelyne

    Toxicology plays a key role in understanding the potentially harmful biological effects of nanoparticles, since epidemiological studies are still difficult to implement given the lack of data concerning exposure. For this reason, in 2005, Günter Oberdörster coined the term `nanotoxicology' to specify the emerging discipline that dealt with ultrafine particles (UFP). It involves in vivo or in vitro studies under controlled conditions to establish the dose-response relationship, so difficult to expose by epidemiological studies. It also aims to determine the thresholds below which biological effects are no longer observed. It is concerned with the role played by properties specific to nanoparticles in the biological response: size, surface reactivity, chemical composition, solubility, etc.

  17. Synthesis of magnetite nanoparticles using electrochemical oxidation

    OpenAIRE

    Levitin, Ye. Ya.; Roy, I. D.; Kryskiv, O. S.; Chan, T.M.

    2014-01-01

    The monodisperse magnetite nanoparticles are promising for use in the biomedical industry for targeted drug delivery, cell separation and biochemical products, Magnetic Resonance Imaging, immunological studies, etc.Classic method for the synthesis of magnetite is the chemical condensation Elmore’s, it is simple and cheap, but it is complicated by the formation of side compounds which impair the magnetic properties of the final product. Biological and medical purposes require high purity magne...

  18. Rapid degradation of zinc oxide nanoparticles by phosphate ions

    Directory of Open Access Journals (Sweden)

    Rudolf Herrmann

    2014-11-01

    Full Text Available Zinc oxide nanoparticles are highly sensitive towards phosphate ions even at pH 7. Buffer solutions and cell culture media containing phosphate ions are able to destroy ZnO nanoparticles within a time span from less than one hour to one day. The driving force of the reaction is the formation of zinc phosphate of very low solubility. The morphology of the zinc oxide particles has only a minor influence on the kinetics of this reaction. Surface properties related to different production methods and the presence and absence of labelling with a perylene fluorescent dye are more important. Particles prepared under acidic conditions are more resistant than those obtained in basic or neutral reaction medium. Surprisingly, the presence of a SiO2 coating does not impede the degradation of the ZnO core. In contrast to phosphate ions, β-glycerophosphate does not damage the ZnO nanoparticles. These findings should be taken into account when assessing the biological effects or the toxicology of zinc oxide nanoparticles.

  19. Cerium fluoride nanoparticles protect cells against oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Shcherbakov, Alexander B.; Zholobak, Nadezhda M. [Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kyiv D0368 (Ukraine); Baranchikov, Alexander E. [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); Ryabova, Anastasia V. [Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow 115409 (Russian Federation); Ivanov, Vladimir K., E-mail: van@igic.ras.ru [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Tomsk State University, Tomsk 634050 (Russian Federation)

    2015-05-01

    A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF{sub 3}:Tb nanoparticles can be used to visualize these nanoparticles' accumulation in cells using confocal laser scanning microscopy. Cerium fluoride nanoparticles are shown for the first time to protect both organic molecules and living cells from the oxidative action of hydrogen peroxide. Both non-doped and terbium-doped CeF{sub 3} nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. - Highlights: • Facile method of CeF{sub 3} and CeF{sub 3}:Tb stable aqueous sols synthesis is proposed. • Naked CeF{sub 3} nanoparticles are shown to be non-toxic and to protect cells from the action of H{sub 2}O{sub 2}. • CeF{sub 3} and CeF{sub 3}:Tb nanoparticles are shown to protect living cells against the vesicular stomatitis virus.

  20. Cerium fluoride nanoparticles protect cells against oxidative stress

    International Nuclear Information System (INIS)

    A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF3:Tb nanoparticles can be used to visualize these nanoparticles' accumulation in cells using confocal laser scanning microscopy. Cerium fluoride nanoparticles are shown for the first time to protect both organic molecules and living cells from the oxidative action of hydrogen peroxide. Both non-doped and terbium-doped CeF3 nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. - Highlights: • Facile method of CeF3 and CeF3:Tb stable aqueous sols synthesis is proposed. • Naked CeF3 nanoparticles are shown to be non-toxic and to protect cells from the action of H2O2. • CeF3 and CeF3:Tb nanoparticles are shown to protect living cells against the vesicular stomatitis virus

  1. Noble Metal Nanoparticle-loaded Mesoporous Oxide Microspheres for Catalysis

    Science.gov (United States)

    Jin, Zhao

    Noble metal nanoparticles/nanocrystals have attracted much attention as catalysts due to their unique characteristics, including high surface areas and well-controlled facets, which are not often possessed by their bulk counterparts. To avoid the loss of their catalytic activities brought about by their size and shape changes during catalytic reactions, noble metal nanoparticles/nanocrystals are usually dispersed and supported finely on solid oxide supports to prevent agglomeration, nanoparticle growth, and therefore the decrease in the total surface area. Moreover, metal oxide supports can also play important roles in catalytic reactions through the synergistic interactions with loaded metal nanoparticles/nanocrystals. In this thesis, I use ultrasonic aerosol spray to produce hybrid microspheres that are composed of noble metal nanoparticles/nanocrystals embedded in mesoporous metal oxide matrices. The mesoporous metal oxide structure allows for the fast diffusion of reactants and products as well as confining and supporting noble metal nanoparticles. I will first describe my studies on noble metal-loaded mesoporous oxide microspheres as catalysts. Three types of noble metals (Au, Pt, Pd) and three types of metal oxide substrates (TiO2, ZrO2, Al 2O3) were selected, because they are widely used for practical catalytic applications involved in environmental cleaning, pollution control, petrochemical, and pharmaceutical syntheses. By considering every possible combination of the noble metals and oxide substrates, nine types of catalyst samples were produced. I characterized the structures of these catalysts, including their sizes, morphologies, crystallinity, and porosities, and their catalytic performances by using a representative reduction reaction from nitrobenzene to aminobenzene. Comparison of the catalytic results reveals the effects of the different noble metals, their incorporation amounts, and oxide substrates on the catalytic abilities. For this particular

  2. Electrophoretic deposition of multi-walled carbon nanotubes on porous anodic aluminum oxide using ionic liquid as a dispersing agent

    Science.gov (United States)

    Hekmat, F.; Sohrabi, B.; Rahmanifar, M. S.; Jalali, A.

    2015-06-01

    Multi-wall carbon nanotubes (MW-CNTs) have been arranged in nanochannels of anodic aluminum oxide template (AAO) by electrophoretic deposition (EPD) to make a vertically-aligned carbon nanotube (VA-CNT) based electrode. Well ordered AAO templates were prepared by a two-step anodizing process by applying a constant voltage of 45 V in oxalic acid solution. The stabilized CNTs in a water-soluble room temperature ionic liquid (1-methyl-3-octadecylimidazolium bromide), were deposited in the pores of AAO templates which were conductive by deposition of Ni nanoparticles in the bottom of pores. In order to obtain ideal results, different EPD parameters, such as concentration of MWCNTs and ionic liquid on stability of MWCNT suspensions, deposition time and voltage which are applied in EPD process and also optimal conditions for anodizing of template were investigated. The capacitive performance of prepared electrodes was analyzed by measuring the specific capacitance from cyclic voltammograms and the charge-discharge curves. A maximum value of 50 Fg-1 at the scan rate of 20 mV s-1was achieved for the specific capacitance.

  3. In vivo efficacy and toxicity evaluation of polycaprolactone nanoparticles and aluminum based admixture formulation as vaccine delivery system.

    Science.gov (United States)

    Bansal, Vivek; Kumar, Manoj; Bhardwaj, Arun; Brahmne, H G; Singh, Harpal

    2015-10-13

    Delivery of antigen through admixture formulation containing poly caprolactone (PCL) and aluminum phosphate was studied as a promising strategy to generate antigen specific immune response. The present study demonstrates the synergistic effect of admixture formulation of PCL with reduced aluminum (PCL-Al 0.2 mg-TT and PCL-PEG-Al 0.2 mg-TT) as a potential adjuvant system using tetanus toxoid (TT) as a model antigen. On evaluation of the magnitude of efficacy for the proposed formulation by ELISA as well as challenge method, persistent and strong antibody response was obtained throughout the 180 day study period on storage at 5 ± 3 °C. In comparison to the aluminum phosphate based conventional tetanus vaccine, higher levels of IFN-γ and IL-4 were obtained with PCL-Al 0.2 mg-TT and PCL-PEG-Al 0.2 mg-TT, indicating the presence of cell mediated as well as humoral immune responses. Histopathology and serum biochemistry profile in mice further indicated the suitability of the proposed formulation. Percent adsorption/encapsulation of the antigen also increased to nearly 95% in the admixture formulation compared to 55% adsorption in the conventional tetanus vaccine. The present study established a useful baseline for designing biocompatible and effective delivery system for toxoid vaccines through judicious use of PCL based biodegradable nanoparticles in combination with aluminum phosphate. PMID:26343498

  4. Surface characterization and reactivity of vanadium-tin oxide nanoparticles

    Science.gov (United States)

    Wang, Chien-Tsung; Chen, Miao-Ting; Lai, De-Lun

    2011-03-01

    Surface state and reactivity of vanadium-tin mixed oxide nanoparticles (V/Sn ratios 0.05-0.2) were characterized by spectroscopic techniques and catalytic measurements. Analyses by X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS) revealed that the oxidation state and surface structure of vanadium oxide species and the electronic interaction between Sn and V atoms are dependent upon the vanadium content. These oxides were evaluated as catalysts for methanol oxidation in a fixed-bed reactor. Both reaction rate and formaldehyde selectivity increased with increasing the vanadium amount in catalyst. Results demonstrate that the V 5+ site in the bridging V-O-Sn structure exhibits a high redox activity to facilitate the transformation of adsorbed methoxy to formaldehyde and that the vanadium dispersion plays a crucial role in the surface reactivity. A mechanism that elucidates the catalytic redox process is proposed.

  5. Facile and green synthesis of silver nanoparticles using oxidized pectin

    Energy Technology Data Exchange (ETDEWEB)

    Tummalapalli, Mythili; Deopura, B.L. [Bioengineering Lab, Department of Textile Technology, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Alam, M.S. [Department of Chemistry, Jamia Hamdard, New Delhi 110062 (India); Gupta, Bhuvanesh, E-mail: bgupta@textile.iitd.ernet.in [Bioengineering Lab, Department of Textile Technology, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India)

    2015-05-01

    In the current work, an alternative route for facile synthesis of nanosilver is reported. Oxidized pectin has been used as the reducing agent as well as the stabilizing agent, resulting in the formation of oxidized pectin-nanosilver (OP-NS) core sheath nanohydrogels. The effect of reaction parameters on the synthesized nanoparticles is investigated. The structural and morphological features have been analyzed using X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) respectively. The crystal size of the synthesized nanosilver was calculated to be 28.76 nm. While the average size of the core sheath structure varied from 289 nm to 540 nm, the size of the silver nanoparticle entities at the core varied from 100 nm to 180 nm, with variation in reaction time. From the morphological examination, it could be seen that flower like nanostructures are formed with nanosilver in the core surrounded by a polymeric halo. - Highlights: • In-situ reduction of silver nitrate to nanosilver was carried out using oxidized pectin. • Oxidized pectin-nanosilver nanohydrogels were synthesized. • Nanoparticles with flower like morphology and face centered cubic crystal structure were fabricated.

  6. Facile and green synthesis of silver nanoparticles using oxidized pectin

    International Nuclear Information System (INIS)

    In the current work, an alternative route for facile synthesis of nanosilver is reported. Oxidized pectin has been used as the reducing agent as well as the stabilizing agent, resulting in the formation of oxidized pectin-nanosilver (OP-NS) core sheath nanohydrogels. The effect of reaction parameters on the synthesized nanoparticles is investigated. The structural and morphological features have been analyzed using X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) respectively. The crystal size of the synthesized nanosilver was calculated to be 28.76 nm. While the average size of the core sheath structure varied from 289 nm to 540 nm, the size of the silver nanoparticle entities at the core varied from 100 nm to 180 nm, with variation in reaction time. From the morphological examination, it could be seen that flower like nanostructures are formed with nanosilver in the core surrounded by a polymeric halo. - Highlights: • In-situ reduction of silver nitrate to nanosilver was carried out using oxidized pectin. • Oxidized pectin-nanosilver nanohydrogels were synthesized. • Nanoparticles with flower like morphology and face centered cubic crystal structure were fabricated

  7. Selective Electrocatalytic Activity of Ligand Stabilized Copper Oxide Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kauffman, Douglas R; Ohodnicki, Paul R; Kail, Brian W; Matranga, Christopher

    2011-01-01

    Ligand stabilization can influence the surface chemistry of Cu oxide nanoparticles (NPs) and provide unique product distributions for electrocatalytic methanol (MeOH) oxidation and CO{sub 2} reduction reactions. Oleic acid (OA) stabilized Cu{sub 2}O and CuO NPs promote the MeOH oxidation reaction with 88% and 99.97% selective HCOH formation, respectively. Alternatively, CO{sub 2} is the only reaction product detected for bulk Cu oxides and Cu oxide NPs with no ligands or weakly interacting ligands. We also demonstrate that OA stabilized Cu oxide NPs can reduce CO{sub 2} into CO with a {approx}1.7-fold increase in CO/H{sub 2} production ratios compared to bulk Cu oxides. The OA stabilized Cu oxide NPs also show 7.6 and 9.1-fold increases in CO/H{sub 2} production ratios compared to weakly stabilized and non-stabilized Cu oxide NPs, respectively. Our data illustrates that the presence and type of surface ligand can substantially influence the catalytic product selectivity of Cu oxide NPs.

  8. Kinetics and thermodynamics of aluminum oxide nanopowder as adsorbent for Fe (III from aqueous solution

    Directory of Open Access Journals (Sweden)

    Mohamed A. Mahmoud

    2015-06-01

    Full Text Available Batch adsorption of Fe (III from aqueous solution by aluminum oxide nanopowder was studied in batch system. The removal efficiency (99.9% was obtained at pH 4 and 50 min contact time. The results indicate that the process follows Langmuir isotherm and pseudo-second-order kinetics model. As well as the thermodynamic data indicated that the exothermic nature process. The values of enthalpy (ΔH°, mean free energy (E and activation energy (Ea indicate that the adsorption process is physical sorption.

  9. Investigation of the radiation defect in aluminum oxide by the spectrum of diffuse reflection

    International Nuclear Information System (INIS)

    Full text : The results of investigation of radiation defects in the γ irradiated disperse aluminum oxide by the spectrum of diffuse reflection were given in this work. It was shown that, γ irradiation Al2O3 guides absorption in and around tied assistance generation of electron (F+) and hole (V) centers. Multicomponent structure was observed in V centers under hv=2,5-3,2 with maximum under γ=375,390 and 410 nm, appropriated hole centers of V, V= and VOH types. The study of kinetic regularity of capital of the V centers depending on absorbed dose. General concentration of the hole centers was calculated

  10. Defects and characteristics of the structure and properties of aluminum oxides

    Science.gov (United States)

    Kopylov, V. B.; Aleksandrov, K. A.; Sergeev, E. V.

    2008-07-01

    Based on IR spectroscopy data, it was established that nonstoichiometry defects in the structure of aluminum oxides were components of the Wannier-Mott exciton states and included the Al-O, Al-Al, O2, O{2/+}, O{2/-}, O{2/2-}, O3, and O2 n isolated oscillators in the ground and electronically excited states. It was shown that their presence manifested itself by thermoemission of molecular oxygen singlet forms, excess heat capacity, and anomalous diamagnetism at elevated temperatures.

  11. Rayleigh instability in polymer thin films coated in the nanopores of anodic aluminum oxide templates.

    Science.gov (United States)

    Tsai, Chia-Chan; Chen, Jiun-Tai

    2014-01-14

    We study the Rayleigh instability of polystyrene (PS) thin films coated in the nanopores of anodic aluminum oxide (AAO) templates. After thermal annealing, the surface of the PS thin films undulates and the nanostructures transform from nanotubes to Rayleigh-instability-induced nanostructures (short nanorods with encapsulated air bubbles). With longer annealing times, the nanostructures further transform to nanorods with longer lengths. PS samples with two different molecular weights (24 and 100 kg/mol) are used, and their instability transformation processes are compared. The morphology diagrams of the nanostructures at different stages are also constructed to elucidate the mechanism of the morphology transformation. PMID:24380368

  12. A Single-Tube Nucleic Acid Extraction, Amplification, and Detection Method Using Aluminum Oxide

    OpenAIRE

    Dames, Shale; Bromley, L. Kathryn; Herrmann, Mark; Elgort, Marc; Erali, Maria; Smith, Roger; Voelkerding, Karl V.

    2006-01-01

    A disposable 0.2-ml polymerase chain reaction (PCR) tube modified with an aluminum oxide membrane (AOM) has been developed for the extraction, amplification, and detection of nucleic acids. To assess the dynamic range of AOM tubes for real-time PCR, quantified herpes simplex virus (HSV) DNA was used to compare AOM tubes to standard PCR tubes. AOM PCR tubes used for amplification and detection of quantified HSV-1 displayed a crossing threshold (CT) shift 0.1 cycles greater than PCR tube contro...

  13. Photoluminescence emission of nanoporous anodic aluminum oxide films prepared in phosphoric acid

    Science.gov (United States)

    Nourmohammadi, Abolghasem; Asadabadi, Saeid Jalali; Yousefi, Mohammad Hasan; Ghasemzadeh, Majid

    2012-12-01

    The photoluminescence emission of nanoporous anodic aluminum oxide films formed in phosphoric acid is studied in order to explore their defect-based subband electronic structure. Different excitation wavelengths are used to identify most of the details of the subband states. The films are produced under different anodizing conditions to optimize their emission in the visible range. Scanning electron microscopy investigations confirm pore formation in the produced layers. Gaussian analysis of the emission data indicates that subband states change with anodizing parameters, and various point defects can be formed both in the bulk and on the surface of these nanoporous layers during anodizing.

  14. Field emission properties of low-density carbon nanotubes prepared on anodic aluminum-oxide template

    International Nuclear Information System (INIS)

    Anodic aluminum-oxide (AAO) templates were fabricated by two-step anodizing an Al film. After the Co catalyst had been electrochemically deposited onto the bottom of the AAO template, carbon nanotubes (CNTs) were grown by using catalytic pyrolysis of C2H2 and H2 at 650 .deg. C. Overgrowth of CNTs with low density on the AAO templates was observed. The field-emission measurements on the samples showed a turn-on field of 2.17 V/μm and a field enhancement factor of 5700. The emission pattern on a phosphor screen was quite homogeneous over the area at a relatively low electric field.

  15. Preparation and Characterization of Fe Nanowire Arrays Embedded in Porous Anodic Aluminum Oxide Templates

    Institute of Scientific and Technical Information of China (English)

    迟广俊; 姚素薇

    2004-01-01

    Fe nanowire arrays are prepared by electrodeposition in porous anodic aluminum oxide template from a composite electrolyte solution. These nanowires have an uniform diameter of approximate 25 nm and a length in excess of 2.5μm.The micrographs and crystal structures of Fe nanowlres are studied by transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction(XRD). It is found that each nanowire is essentially a single crystal and has a different orientation in each array. Hysteresis loops of Fe nanowire array show that its easy magnetization direction is perpendicular to the sample plane.

  16. Hydrogenation of Levulinic Acid over Nickel Catalysts Supported on Aluminum Oxide to Prepare γ-Valerolactone

    OpenAIRE

    Jie Fu; Dong Sheng; Xiuyang Lu

    2015-01-01

    Four types of nickel catalysts supported on aluminum oxide (Ni/Al2O3) with different nickel loadings were synthesized using the co-precipitation method and were used for the hydrogenation of levulinic acid (LA) to prepare γ-valerolactone (GVL). The synthesized Ni/Al2O3 catalysts exhibited excellent catalytic activity in dioxane, and the activity of the catalysts was excellent even after being used four times in dioxane. The catalytic activity in dioxane as a solvent was found to be superior t...

  17. Mesoscopic phenomena in oxide nanoparticles systems: processes of growth

    Energy Technology Data Exchange (ETDEWEB)

    Konstantinova, Tetyana, E-mail: matscidep@aim.com; Danilenko, Igor; Glazunova, Valentina; Volkova, Galina; Gorban, Oksana [Donetsk Institute for Physics and Engineering of the NAS of Ukraine (Ukraine)

    2011-09-15

    The process of nanoparticles growth has been investigated and discussed in terms of mesoscopic approach on example of ZrO{sub 2}-3 mol%Y{sub 2}O{sub 3} system. Growth process of nanoparticles synthesized by co-precipitation has three stages: cooperative-oriented crystallization of ordered areas in xerogel polymer matrix and disintegration of crystallized areas (350-400 Degree-Sign C); oriented attachment of particles into single crystal caused by electrostatic interaction (400-600 Degree-Sign C); attachment of particles to single and poly-crystals by oxygen diffusion through vacancies in surface layers of joining crystals (600-1,000 Degree-Sign C). Proposed conception on mesoscopic processes of nanoparticles formation make the understanding and theoretical description of significant amount of experimental data possible and open the way for purposeful governing by oxide powder system on the stages of obtaining, compaction, and sintering.

  18. Mesoscopic phenomena in oxide nanoparticles systems: processes of growth

    International Nuclear Information System (INIS)

    The process of nanoparticles growth has been investigated and discussed in terms of mesoscopic approach on example of ZrO2–3 mol%Y2O3 system. Growth process of nanoparticles synthesized by co-precipitation has three stages: cooperative-oriented crystallization of ordered areas in xerogel polymer matrix and disintegration of crystallized areas (350–400 °C); oriented attachment of particles into single crystal caused by electrostatic interaction (400–600 °C); attachment of particles to single and poly-crystals by oxygen diffusion through vacancies in surface layers of joining crystals (600–1,000 °C). Proposed conception on mesoscopic processes of nanoparticles formation make the understanding and theoretical description of significant amount of experimental data possible and open the way for purposeful governing by oxide powder system on the stages of obtaining, compaction, and sintering.

  19. Ca alginate as scaffold for iron oxide nanoparticles synthesis

    Directory of Open Access Journals (Sweden)

    P. V. Finotelli

    2008-12-01

    Full Text Available Recently, nanotechnology has developed to a stage that makes it possible to process magnetic nanoparticles for the site-specific delivery of drugs. To this end, it has been proposed as biomaterial for drug delivery system in which the drug release rates would be activated by a magnetic external stimuli. Alginate has been used extensively in the food, pharmaceutical and biomedical industries for their gel forming properties in the presence of multivalent cations. In this study, we produced iron oxide nanoparticles by coprecipitation of Fe(III and Fe(II. The nanoparticles were entrapped in Ca alginate beads before and after alginate gelation. XRD analysis showed that particles should be associated to magnetite or maghemite with crystal size of 9.5 and 4.3 nm, respectively. Studies using Mössbauer spectroscopy corroborate the superparamagnetic behavior. The combination of magnetic properties and the biocompatibility of alginate suggest that this biomaterial may be used as biomimetic system.

  20. The uniformity of Al distribution in aluminum-doped zinc oxide films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Luka, G., E-mail: gluka@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Wachnicki, L.; Witkowski, B.S.; Krajewski, T.A.; Jakiela, R.; Guziewicz, E. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Godlewski, M. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Department of Mathematics and Natural Sciences, College of Science, Cardinal Stefan Wyszynski University, Warsaw (Poland)

    2011-02-25

    We investigated the aluminum distribution in aluminum-doped zinc oxide films grown by atomic layer deposition. Surface morphology, structure, composition and electrical properties of obtained films were studied. For the aluminum content less than 2 at.%, a periodicity of Al distribution along the layer depth was observed. This periodicity diminished significantly after annealing the samples in nitrogen atmosphere at 300 deg. C. For the Al content higher than 2 at.%, its distribution in ZnO:Al films was uniform within the depth measurement accuracy of {approx}5-10 nm.

  1. Effect of environment on iodine oxidation state and reactivity with aluminum.

    Science.gov (United States)

    Smith, Dylan K; McCollum, Jena; Pantoya, Michelle L

    2016-04-20

    Iodine oxide is a highly reactive solid oxidizer and with its abundant generation of iodine gas during reaction, this oxidizer also shows great potential as a biocidal agent. A problem with using I2O5 in an energetic mixture is its highly variable reactive behavior. This study isolates the variable reactivity associated with I2O5 as a function of its chemical reaction in various environments. Specifically, aluminum fuel and iodine oxide powder are combined using a carrier fluid to aid intermixing. The carrier fluid is shown to significantly affect the oxidation state of iodine oxide, thereby affecting the reactivity of the mixture. Four carrier fluids were investigated ranging in polarity and water miscibility in increasing order from hexane water as well as untreated, dry-mixed reactants. Oxidation state and reactivity were examined with experimental techniques including X-ray photoelectric spectroscopy (XPS) and differential scanning calorimetry (DSC). Results are compared with thermal equilibrium simulations. Flame speeds increased with polarity of the fluid used to intermix the powder and ranged from 180 to 1202 m s(-1). The I2O5 processed in the polar fluids formed hydrated states of iodine oxide: HIO3 and HI3O8; and, the nonpolar and dry-mixed samples formed: I2O4 and I4O9. During combustion, the hydrated iodine oxides rapidly dehydrated from HIO3 to HI3O8 and from HI3O8 to I2O5. Both steps release 25% of their mass as vapor during combustion. Increased gas generation enhances convective energy transport and accounts for the increase in reactivity seen in the mixtures processed in polar fluids. These results explain the chemical mechanisms underlying the variable reactivity of I2O5 that are a function of the oxide's highly reactive nature with its surrounding environment. These results will significantly impact the selection of carrier fluid in the synthesis approach for iodine containing reactive mixtures. PMID:27052472

  2. Study on phosphating treatment of aluminum alloy: role of yttrium oxide

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shenglin

    2009-01-01

    Zinc phosphate coatings formed on 6061-Al alloy, after dipping in phosphating solutions containing different amounts of Y2O3(yttrium oxide), were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical measurements. Significant variations in the morphology and corrosion resistance afforded by zinc phosphate coating were especially observed as Y2O3 in phosphating solution varied from 0 to 40 mg/L. The addition of Y2O3 changed the initial potential of the interface between aluminum alloy substrate and phosphating solution and increased the number of nucleation sites. The phosphate coating thereby was less porous structure and covered the surface of aluminum alloy completely within short phosphating time. Phosphate coating was mainly composed of Zn3(PO4)2-4H2O (hopeite) and AIPO4(aluminum phosphate). Y2O3, as an additive of phosphatization, accelerated precipitation and refined the gain size of phosphate coating. The corrosion resistance of zinc phosphate coating in 3% NaCl solution was improved as shown by po-larization measurement. In the present research, the optimal amount of Y2O3 was 10-20 mg/L, and the optimal phosphating time was 600 s.

  3. Coverage and disruption of phospholipid membranes by oxide nanoparticles.

    Science.gov (United States)

    Pera, Harke; Nolte, Tom M; Leermakers, Frans A M; Kleijn, J Mieke

    2014-12-01

    We studied the interactions of silica and titanium dioxide nanoparticles with phospholipid membranes and show how electrostatics plays an important role. For this, we systematically varied the charge density of both the membranes by changing their lipid composition and the oxide particles by changing the pH. For the silica nanoparticles, results from our recently presented fluorescence vesicle leakage assay are combined with data on particle adsorption onto supported lipid bilayers obtained by optical reflectometry. Because of the strong tendency of the TiO2 nanoparticles to aggregate, the interaction of these particles with the bilayer was studied only in the leakage assay. Self-consistent field (SCF) modeling was applied to interpret the results on a molecular level. At low charge densities of either the silica nanoparticles or the lipid bilayers, no electrostatic barrier to adsorption exists. However, the adsorption rate and adsorbed amounts drop with increasing (negative) charge densities on particles and membranes because of electric double-layer repulsion, which is confirmed by the effect of the ionic strength. SCF calculations show that charged particles change the structure of lipid bilayers by a reorientation of a fraction of the zwitterionic phosphatidylcholine (PC) headgroups. This explains the affinity of the silica particles for pure PC lipid layers, even at relatively high particle charge densities. Particle adsorption does not always lead to the disruption of the membrane integrity, as is clear from a comparison of the leakage and adsorption data for the silica particles. The attraction should be strong enough, and in line with this, we found that for positively charged TiO2 particles vesicle disruption increases with increasing negative charge density on the membranes. Our results may be extrapolated to a broader range of oxide nanoparticles and ultimately may be used for establishing more accurate nanoparticle toxicity assessments and drug

  4. Copper nanoparticles grown under hydrogen: Study of the surface oxide

    International Nuclear Information System (INIS)

    Copper nanoparticles with sizes between 10 nm and 50 nm were grown by condensation in hydrogen at pressures from 10 Pa to 1200 Pa. The crystallite size ranged from 10 nm to 25 nm using the Scherrer method. X-ray diffraction showed the reflections of metallic copper occasionally mixed with an oxidized phase (CuO or Cu2O). As shown by TEM examination, the smaller particles that did not exceed 25 nm exhibited faceted morphologies whereas the bigger ones had ovaled-spherical forms sometimes containing twins. X-ray photoelectron spectroscopy revealed that the nanoparticles consist of a copper core, completely surrounded by a Cu2O shell, which is oxidized to CuO at the surface layer.

  5. Potential toxicity of superparamagnetic iron oxide nanoparticles (SPION

    Directory of Open Access Journals (Sweden)

    Neenu Singh

    2010-09-01

    Full Text Available Superparamagnetic iron oxide nanoparticles (SPION are being widely used for various biomedical applications, for example, magnetic resonance imaging, targeted delivery of drugs or genes, and in hyperthermia. Although, the potential benefits of SPION are considerable, there is a distinct need to identify any potential cellular damage associated with these nanoparticles. Besides focussing on cytotoxicity, the most commonly used determinant of toxicity as a result of exposure to SPION, this review also mentions the importance of studying the subtle cellular alterations in the form of DNA damage and oxidative stress. We review current studies and discuss how SPION, with or without different surface coating, may cause cellular perturbations including modulation of actin cytoskeleton, alteration in gene expression profiles, disturbance in iron homeostasis and altered cellular responses such as activation of signalling pathways and impairment of cell cycle regulation. The importance of protein–SPION interaction and various safety considerations relating to SPION exposure are also addressed.

  6. Synthesis of zinc oxide nanoparticles elaborated by microemulsion method

    Energy Technology Data Exchange (ETDEWEB)

    Yildirim, Ozlem Altintas [Department of Metallurgical and Materials Engineering, Middle East Technical University, 06531 Ankara (Turkey); Durucan, Caner, E-mail: cdurucan@metu.edu.t [Department of Metallurgical and Materials Engineering, Middle East Technical University, 06531 Ankara (Turkey)

    2010-09-17

    Graphical abstract: . Display Omitted Research highlights: {yields} Spherical and rod-like ZnO nanostructures obtained in reverse microemulsion. {yields} Morphological variations for microemulsion products with surfactant amount. {yields} Formation mechanism for ZnO nanosructres in a reverse emulsion system. {yields} Optical properties of the ZnO nanoparticles. - Abstract: Zinc oxide (ZnO) nanoparticles were synthesized by a reverse microemulsion system formed from sodium bis(2-ethylhexyl)sulfosuccinate (Aerosol OT, or AOT):glycerol:n-heptane. The zinc precursor was zinc acetate dihydrate. The formation of ZnO nanoparticles was achieved by calcination of premature zinc glycerolate microemulsion product in air at 300, 400 and 500 {sup o}C. The crystal structure and the morphology of the ZnO nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Thermal analysis was employed to reveal structural and chemical changes during calcination. Both surfactant concentrations - AOT - in the initial microemulsion formulation and the calcination temperature influenced the morphology and size of the ZnO nanoparticles. Low surfactant concentrations (5:5:90, AOT:glycerol:n-heptane, wt.%) resulted in formation of spherical ZnO nanoparticles. The average particle size increased from 15 {+-} 1 to 24 {+-} 1 nm with calcination temperature, but spherical morphology remained unchanged after all calcination treatments. The microemulsion system containing higher surfactant amount (30:5:65, AOT:glycerol:n-heptane, wt.%) resulted in rod-like ZnO nanostructures after calcination at 300 and 400 {sup o}C, with a diameter of 22 {+-} 3 and 28 {+-} 1 nm; and with a length of 66 {+-} 3 and 72 {+-} 1 nm, respectively. Further increase in the calcination temperature to 500 {sup o}C initiated rod-to-sphere shape transformation for the ZnO nanoparticles produced using this particular microemulsion formulation. For all ZnO microemulsion products, the

  7. Enzymatic oxidative biodegradation of nanoparticles: Mechanisms, significance and applications.

    Science.gov (United States)

    Vlasova, Irina I; Kapralov, Alexandr A; Michael, Zachary P; Burkert, Seth C; Shurin, Michael R; Star, Alexander; Shvedova, Anna A; Kagan, Valerian E

    2016-05-15

    Biopersistence of carbon nanotubes, graphene oxide (GO) and several other types of carbonaceous nanomaterials is an essential determinant of their health effects. Successful biodegradation is one of the major factors defining the life span and biological responses to nanoparticles. Here, we review the role and contribution of different oxidative enzymes of inflammatory cells - myeloperoxidase, eosinophil peroxidase, lactoperoxidase, hemoglobin, and xanthine oxidase - to the reactions of nanoparticle biodegradation. We further focus on interactions of nanomaterials with hemoproteins dependent on the specific features of their physico-chemical and structural characteristics. Mechanistically, we highlight the significance of immobilized peroxidase reactive intermediates vs diffusible small molecule oxidants (hypochlorous and hypobromous acids) for the overall oxidative biodegradation process in neutrophils and eosinophils. We also accentuate the importance of peroxynitrite-driven pathways realized in macrophages via the engagement of NADPH oxidase- and NO synthase-triggered oxidative mechanisms. We consider possible involvement of oxidative machinery of other professional phagocytes such as microglial cells, myeloid-derived suppressor cells, in the context of biodegradation relevant to targeted drug delivery. We evaluate the importance of genetic factors and their manipulations for the enzymatic biodegradation in vivo. Finally, we emphasize a novel type of biodegradation realized via the activation of the "dormant" peroxidase activity of hemoproteins by the nano-surface. This is exemplified by the binding of GO to cyt c causing the unfolding and 'unmasking' of the peroxidase activity of the latter. We conclude with the strategies leading to safe by design carbonaceous nanoparticles with optimized characteristics for mechanism-based targeted delivery and regulatable life-span of drugs in circulation. PMID:26768553

  8. Nitric oxide-releasing polymeric nanoparticles against Trypanosoma cruzi

    Science.gov (United States)

    Seabra, A. B.; Kitice, N. A.; Pelegrino, M. T.; Lancheros, C. A. C.; Yamauchi, L. M.; Pinge-Filho, P.; Yamada-Ogatta, S. F.

    2015-05-01

    Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite, Trypanosoma cruzi (T. cruzi), and the disease remains a major health problem in many Latin American countries. Several papers report that the killing of the parasite is dependent on the production of nitric oxide (NO). The endogenous free radical NO is an important cellular signalling molecule that plays a key role in the defense against pathogens, including T. cruzi. As T. cruzi is able to compromise host macrophages decreasing endogenous NO production, the administration of exogenous NO donors represents an interesting strategy to combat Chagas disease. Thus, the aims of this study were to prepare and evaluate the antimicrobial activity of NO-releasing polymeric nanoparticles against T. cruzi. Biocompatible polymeric nanoparticles composed of chitosan/sodium tripolyphosphate(TPP) were prepared and used to encapsulate mercaptosuccinic acid (MSA), which is a thiol-containing molecule. Nitrosation of free thiols (SH) groups of MSA were performed by the addition of equimolar amount of sodium nitrite (NaNO2), leading to the formation of S-nitroso-MSA-containing nanoparticles. These polymeric nanoparticles act as spontaneous NO donors, with free NO release. The results show the formation of nanoparticles with average hydrodynamic diameter ranging from 270 to 500 nm, average of polydispersity index of 0.35, and encapsulation efficiency in the range of 99%. The NO release kinetics from the S-nitroso-MSA-containing nanoparticles showed sustained and controlled NO release over several hours. The microbicidal activity of S-nitroso-MSA-containing nanoparticles was evaluated by incubating NO-releasing nanoparticles (200 - 600 μg/mL) with replicative and non-infective epimastigote, and non-replicative and infective trypomastigote forms of T. cruzi. In addition, a significant decrease in the percentage of macrophage-infected (with amastigotes) and

  9. Water-soluble iron oxide nanoparticles for nanomedicine

    OpenAIRE

    Cooper, Christy L.; Reece, Lisa M; Key, J.; Bergstrom, Donald E.; Leary, James F

    2008-01-01

    Monodisperse iron oxide nanoparticles (MION) are easily synthesized in organic solvents for industrial applications. However, biological applications require that the particles by readily dispersed in aqueous solutions. To improve their dispersion in aqueous solution, MION particles can be conjugated to water soluble polymers. These water soluble particles can then be used for nanomedicine, which utilizes nanometer scale constructs to treat diseases at the cellular level. Here we report the s...

  10. Synthesis, Characterization, and Antimicrobial Activity of Copper Oxide Nanoparticles

    OpenAIRE

    Ahamed, Maqusood; Alhadlaq, Hisham A; Khan, M. A. Majeed; Karuppiah, Ponmurugan; Naif A. Al-Dhabi

    2014-01-01

    We studied the structural and antimicrobial properties of copper oxide nanoparticles (CuO NPs) synthesized by a very simple precipitation technique. Copper (II) acetate was used as a precursor and sodium hydroxide as a reducing agent. X-ray diffraction patter (XRD) pattern showed the crystalline nature of CuO NPs. Field emission scanning electron microscope (FESEM) and field emission transmission electron microscope (FETEM) demonstrated the morphology of CuO NPs. The average diameter of CuO N...

  11. Size dependent magnetic properties of iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Jhunu; Haik, Yousef. E-mail: haik@eng.fsu.edu; Chen, C.-J.Ching-Jen

    2003-02-01

    {gamma}Fe{sub 2}O{sub 3} nanoparticles has been synthesized by a combination of chemical and ultrasonication procedure and further stabilized with surfactant. Their magnetic properties are compared with the different fractions (10-12, 20-30, 100-150 nm) of commercially available iron oxide. The sizes obtained from the scanning transmission electron micrographs are correlated with the magnetic properties of the particles.

  12. Precipitation of Zinc Oxide Nanoparticles in Bicontinuous Microemulsions

    OpenAIRE

    Liliana E. Romo; Hened Saade; Bertha Puente; Ma. Luisa López; Rebeca Betancourt; Raúl G. López

    2011-01-01

    Zinc oxide nanoparticles were obtained directly, avoiding the calcination step, by precipitation at 70°C in bicontinuous microemulsions stabilized with a mixture of surfactants sodium bis (2-ethylhexyl) sulfosuccinate/sodium dodecyl sulfate (2/1, wt./wt.) containing 0.7 M zinc nitrate aqueous solution. Two concentrations of aqueous solution of precipitating agent sodium hydroxide were used under different dosing times on microemulsion. Characterization by X-ray diffraction and electron micros...

  13. Comparative proteomic analysis of the molecular responses of mouse macrophages to titanium dioxide and copper oxide nanoparticles unravels some toxic mechanisms for copper oxide nanoparticles in macrophages.

    Directory of Open Access Journals (Sweden)

    Sarah Triboulet

    Full Text Available Titanium dioxide and copper oxide nanoparticles are more and more widely used because of their catalytic properties, of their light absorbing properties (titanium dioxide or of their biocidal properties (copper oxide, increasing the risk of adverse health effects. In this frame, the responses of mouse macrophages were studied. Both proteomic and targeted analyses were performed to investigate several parameters, such as phagocytic capacity, cytokine release, copper release, and response at sub toxic doses. Besides titanium dioxide and copper oxide nanoparticles, copper ions were used as controls. We also showed that the overall copper release in the cell does not explain per se the toxicity observed with copper oxide nanoparticles. In addition, both copper ion and copper oxide nanoparticles, but not titanium oxide, induced DNA strands breaks in macrophages. As to functional responses, the phagocytic capacity was not hampered by any of the treatments at non-toxic doses, while copper ion decreased the lipopolysaccharide-induced cytokine and nitric oxide productions. The proteomic analyses highlighted very few changes induced by titanium dioxide nanoparticles, but an induction of heme oxygenase, an increase of glutathione synthesis and a decrease of tetrahydrobiopterin in response to copper oxide nanoparticles. Subsequent targeted analyses demonstrated that the increase in glutathione biosynthesis and the induction of heme oxygenase (e.g. by lovastatin/monacolin K are critical for macrophages to survive a copper challenge, and that the intermediates of the catecholamine pathway induce a strong cross toxicity with copper oxide nanoparticles and copper ions.

  14. Recent Advances in the Synthesis and Stabilization of Nickel and Nickel Oxide Nanoparticles: A Green Adeptness

    Science.gov (United States)

    Rani, Aneela

    2016-01-01

    Green protocols for the synthesis of nanoparticles have been attracting a lot of attention because they are eco-friendly, rapid, and cost-effective. Nickel and nickel oxide nanoparticles have been synthesized by green routes and characterized for impact of green chemistry on the properties and biological effects of nanoparticles in the last five years. Green synthesis, properties, and applications of nickel and nickel oxide nanoparticles have been reported in the literature. This review summarizes the synthesis of nickel and nickel oxide nanoparticles using different biological systems. This review also provides comparative overview of influence of chemical synthesis and green synthesis on structural properties of nickel and nickel oxide nanoparticles and their biological behavior. It concludes that green methods for synthesis of nickel and nickel oxide nanoparticles are better than chemical synthetic methods.

  15. Recent Advances in the Synthesis and Stabilization of Nickel and Nickel Oxide Nanoparticles: A Green Adeptness

    OpenAIRE

    Imran Din, Muhammad; Rani, Aneela

    2016-01-01

    Green protocols for the synthesis of nanoparticles have been attracting a lot of attention because they are eco-friendly, rapid, and cost-effective. Nickel and nickel oxide nanoparticles have been synthesized by green routes and characterized for impact of green chemistry on the properties and biological effects of nanoparticles in the last five years. Green synthesis, properties, and applications of nickel and nickel oxide nanoparticles have been reported in the literature. This review summa...

  16. Electrochemical Sensor for Oxidation of NO Based on Au-Pt Nanoparticles Self-assembly Film

    Institute of Scientific and Technical Information of China (English)

    XIE,Jia; YU,Zhihui; XIA,Dingguo

    2009-01-01

    Au-Pt bimetallic nanoparticles film used as an efficient electrochemical sensor was prepared by self-assembled Au-Pt bimetallic nanoparticles on a glassy carbon (GC) substrate using thioglycolic acid as a linker. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) showed that the Au-Pt nanoparticles self-assembly film was dense and uniform. Electrochemical experiments revealed that Au-Pt bimetallic nanoparticles film/GC electrode showed high electrocatalytic activity to the oxidation of nitric oxide.

  17. Comparison of Calcium Phosphate and Zinc Oxide Nanoparticles as Dermal Penetration Enhancers for Albumin

    OpenAIRE

    Shokri, Narges; Javar, H. A.

    2015-01-01

    Dermal drug delivery is highly preferred by patients due to its several advantages. Protein therapeutics have attracted huge attention recently. Since dermal delivery of proteins encounter problems, in this investigation, zinc oxide nanoparticles and calcium phosphate nanoparticles were compared as enhancers for dermal permeation of albumin. Albumin was applied simultaneously with zinc oxide nanoparticles or calcium phosphate nanoparticles on pieces of mouse skin. Skin permeation of albumin o...

  18. Iron oxide nanoparticle modified monolithic pipette tips for selective enrichment of phosphopeptides

    OpenAIRE

    Křenková, Jana

    2012-01-01

    We have developed iron oxide nanoparticle modified monolithic pipette tips for selective and efficient enrichment of phosphopeptides. Iron oxide nanoparticles were synthesized using a co-precipitation method and stabilized by citrate ions. A stable coating of nanoparticles was obtained via multivalent interactions of citrate ions on the nanoparticle surface with a quaternary amine functionalized surface of the methacrylate based monolithic tips. The performance of the developed and comme...

  19. Multifunctional iron oxide nanoparticles for diagnostics, therapy and macromolecule delivery.

    Science.gov (United States)

    Yen, Swee Kuan; Padmanabhan, Parasuraman; Selvan, Subramanian Tamil

    2013-01-01

    In recent years, multifunctional nanoparticles (NPs) consisting of either metal (e.g. Au), or magnetic NP (e.g. iron oxide) with other fluorescent components such as quantum dots (QDs) or organic dyes have been emerging as versatile candidate systems for cancer diagnosis, therapy, and macromolecule delivery such as micro ribonucleic acid (microRNA). This review intends to highlight the recent advances in the synthesis and application of multifunctional NPs (mainly iron oxide) in theranostics, an area used to combine therapeutics and diagnostics. The recent applications of NPs in miRNA delivery are also reviewed. PMID:24396508

  20. Structural, morphological and optical properties of chromium oxide nanoparticles

    Science.gov (United States)

    Babukutty, Blessy; Parakkal, Fasalurahman; Bhalero, G. M.; Aravind, P. B.; Nair, Swapna S.

    2015-06-01

    Chromium oxide nanoparticles are synthesized by reduction route from chloride precursors with surfactant, trioctylphosphine oxide (TOPO). Structural and morphological characterization are analyzed using X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Transmission Electron micrographs show that the average grain size lies in the range 5nm to 10nm. Optical characterization has been done by UV-VIS spectrophotometer. Distinct optical absorptions of Cr3+ ions show hinting towards the presence of Cr2O3. Presence of oxygen is also confirmed from Electron Energy Loss Spectroscopy (EELS) studies.

  1. Structural, morphological and optical properties of chromium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Babukutty, Blessy; Parakkal, Fasalurahman; Nair, Swapna S., E-mail: swapna.s.nair@gmail.com [School of Mathematical and Physical Sciences, Department of Physics, Central University of Kerala, Kasaragod 671314 (India); Bhalero, G. M. [UGC-DAE, IGCAR, Kalpakkam, TamilNadu (India); Aravind, P. B. [Cochin University of Science and Technology(CUSAT), Cochin (India)

    2015-06-24

    Chromium oxide nanoparticles are synthesized by reduction route from chloride precursors with surfactant, trioctylphosphine oxide (TOPO). Structural and morphological characterization are analyzed using X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Transmission Electron micrographs show that the average grain size lies in the range 5nm to 10nm. Optical characterization has been done by UV-VIS spectrophotometer. Distinct optical absorptions of Cr{sup 3+} ions show hinting towards the presence of Cr{sub 2}O{sub 3}. Presence of oxygen is also confirmed from Electron Energy Loss Spectroscopy (EELS) studies.

  2. Structural, morphological and optical properties of chromium oxide nanoparticles

    International Nuclear Information System (INIS)

    Chromium oxide nanoparticles are synthesized by reduction route from chloride precursors with surfactant, trioctylphosphine oxide (TOPO). Structural and morphological characterization are analyzed using X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Transmission Electron micrographs show that the average grain size lies in the range 5nm to 10nm. Optical characterization has been done by UV-VIS spectrophotometer. Distinct optical absorptions of Cr3+ ions show hinting towards the presence of Cr2O3. Presence of oxygen is also confirmed from Electron Energy Loss Spectroscopy (EELS) studies

  3. Iron oxide nanoparticles for magnetically assisted patterned coatings

    Science.gov (United States)

    Dodi, Gianina; Hritcu, Doina; Draganescu, Dan; Popa, Marcel I.

    2015-08-01

    Iron oxide nanoparticles able to magnetically assemble during the curing stage of a polymeric support to create micro-scale surface protuberances in a controlled manner were prepared and characterized. The bare Fe3O4 particles were obtained by two methods: co-precipitation from an aqueous solution containing Fe3+/Fe2+ ions with a molar ratio of 2:1 and partial oxidation of ferrous ions in alkaline conditions. The products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and magnetization measurement. They were subsequently functionalized using oleic acid, sodium oleate, or non-ionic surfactant mixtures with various hydrophilic to lipophilic balance (HLB) values. Composite nanoparticle-polymer films prepared by spraying were deposited and cured by drying on glass slides under a static magnetic field in the range of 1.5-5.5 mT. Magnetic field generated surface roughness was evidenced by optical and scanning electron microscopy. The optimum hierarchical patterning was obtained with the nanoparticles produced by partial oxidation and functionalized with hydrophobic surfactants. Possible applications may include ice-phobic composite coatings.

  4. Single step radiolytic synthesis of iridium nanoparticles onto graphene oxide

    Science.gov (United States)

    Rojas, J. V.; Molina Higgins, M. C.; Toro Gonzalez, M.; Castano, C. E.

    2015-12-01

    In this work a new approach to synthesize iridium nanoparticles on reduced graphene oxide is presented. The nanoparticles were directly deposited and grown on the surface of the carbon-based support using a single step reduction method through gamma irradiation. In this process, an aqueous isopropanol solution containing the iridium precursor, graphene oxide, and sodium dodecyl sulfate was initially prepared and sonicated thoroughly to obtain a homogeneous dispersion. The samples were irradiated with gamma rays with energies of 1.17 and 1.33 MeV emitted from the spontaneous decay of the 60Co irradiator. The interaction of gamma rays with water in the presence of isopropanol generates highly reducing species homogeneously distributed in the solution that can reduce the Ir precursor down to a zero valence state. An absorbed dose of 60 kGy was used, which according to the yield of reducing species is sufficient to reduce the total amount of precursor present in the solution. This novel approach leads to the formation of 2.3 ± 0.5 nm Ir nanoparticles distributed along the surface of the support. The oxygenated functionalities of graphene oxide served as nucleation sites for the formation of Ir nuclei and their subsequent growth. XPS results revealed that the interaction of Ir with the support occurs through Irsbnd O bonds.

  5. Versatile ferrofluids based on polyethylene glycol coated iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Brullot, W., E-mail: ward.brullot@fys.kuleuven.be [Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Heverlee, Leuven (Belgium); Reddy, N.K. [Department of Chemical Engineering, Katholieke Universiteit Leuven, Willem de Croylaan 46, 3001 Heverlee, Leuven (Belgium); Wouters, J.; Valev, V.K.; Goderis, B. [Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Heverlee, Leuven (Belgium); Vermant, J. [Department of Chemical Engineering, Katholieke Universiteit Leuven, Willem de Croylaan 46, 3001 Heverlee, Leuven (Belgium); Verbiest, T. [Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Heverlee, Leuven (Belgium)

    2012-06-15

    Versatile ferrofluids based on polyethylene glycol coated iron oxide nanoparticles were obtained by a facile protocol and thoroughly characterized. Superparamagnetic iron oxide nanoparticles synthesized using a modified forced hydrolysis method were functionalized with polyethylene glycol silane (PEG silane), precipitated and dried. These functionalized particles are dispersable in a range of solvents and concentrations depending on the desired properties. Examples of tunable properties are magnetic behavior, optical and magneto-optical response, thermal features and rheological behavior. As such, PEG silane functionalized particles represent a platform for the development of new materials that have broad applicability in e.g. biomedical, industrial or photonic environments. Magnetic, optical, magneto-optical, thermal and rheological properties of several ferrofluids based on PEG coated particles with different concentrations of particles dispersed in low molecular mass polyethylene glycol were investigated, establishing the applicability of such materials. - Highlights: Black-Right-Pointing-Pointer Ferrofluids based on polyethylene glycol coated iron oxide nanoparticles. Black-Right-Pointing-Pointer Magnetic, optical, magneto-optical, thermal and rheological characterization of ferrofluids. Black-Right-Pointing-Pointer Tunable properties of versatile polyethylene glycol stabilized ferrofluids.

  6. Impurity-defect structure of anodic aluminum oxide produced by two-sided anodizing in tartaric acid

    Science.gov (United States)

    Chernyakova, K. V.; Vrublevsky, I. A.; Ivanovskaya, M. I.; Kotsikau, D. A.

    2012-03-01

    Porous aluminum oxide is prepared in a 0.4 M aqueous solution of tartaric acid by two-sided anodizing. Fourier Transform IR spectroscopy (FTIR) data reveal the presence, in the alumina, of unoxidized tartarate ions, as well as products of their partial (radical organic products and CO) and complete (CO2) oxidation. Carboxylate ions and elemental carbon contained in the anodic oxide impart a gray color to the films.

  7. Characterization and bacterial toxicity of lanthanum oxide bulk and nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Brabu Balusamy; Yamuna Gowri Kandhasamy; Anitha Senthamizhan; Gopalakrishnan Chandrasekaran; Murugan Siva Subramanian; Kumaravel Tirukalikundram S

    2012-01-01

    This study evaluated the bacterial toxicity of lanthanum oxide micron and nano sized particles using shake flask method against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli,Pseudomonas aeruginosa) bacteria.Particle size,morphology and chemical composition were determined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS).Resuits indicated that lanthanum oxide nanoparticles showed antimicrobial activity against Staphylococcus aureus,but not against Escherichia coli and Pseudomonas aeruginosa.It was speculated that lanthanum oxide produced this effect by interacting with the gram-positive bacterial cell wall.Furthermore,lanthanum oxide bulk particles were found to enhance the pyocyanin pigment production in Pseudomonas aeruginosa.

  8. Nanocarbon synthesis by high-temperature oxidation of nanoparticles

    Science.gov (United States)

    Nomura, Ken-Ichi; Kalia, Rajiv K.; Li, Ying; Nakano, Aiichiro; Rajak, Pankaj; Sheng, Chunyang; Shimamura, Kohei; Shimojo, Fuyuki; Vashishta, Priya

    2016-04-01

    High-temperature oxidation of silicon-carbide nanoparticles (nSiC) underlies a wide range of technologies from high-power electronic switches for efficient electrical grid and thermal protection of space vehicles to self-healing ceramic nanocomposites. Here, multimillion-atom reactive molecular dynamics simulations validated by ab initio quantum molecular dynamics simulations predict unexpected condensation of large graphene flakes during high-temperature oxidation of nSiC. Initial oxidation produces a molten silica shell that acts as an autocatalytic ‘nanoreactor’ by actively transporting oxygen reactants while protecting the nanocarbon product from harsh oxidizing environment. Percolation transition produces porous nanocarbon with fractal geometry, which consists of mostly sp2 carbons with pentagonal and heptagonal defects. This work suggests a simple synthetic pathway to high surface-area, low-density nanocarbon with numerous energy, biomedical and mechanical-metamaterial applications, including the reinforcement of self-healing composites.

  9. Effects of rare earth oxide additives on the thermal behaviors of aluminum nitride ceramics

    Institute of Scientific and Technical Information of China (English)

    YAO Yijun; WANG Ling; LI Chuncheng; JIANG Xiaolong; QIU Tai

    2009-01-01

    The effects of Y_2O_3 and Er_2O_3 on the sintering behaviors, thermal properties and microstructure of AIN ceramics were investigated. The ex-perimental results show that the sintering temperature can be decreased; the relative density and thermal behavior can be improved by adding rare earth oxide in AIN ceramics. For AIN ceramics with 3 wt.% Er_2O_3 additive, the relative density is 98.8%, and the thermal conductivity reaches 106 W·m~(-1)·K~(-1). The microstructure research found that no obvious aluminum erbium oxide was found in AIN ceramics doped with 3 wt.% Er_2O_3, which favored the improvement of the thermal conductivity of AIN ceramics.

  10. Radon test measurements with Ce-doped yttrium aluminum oxide perovskite scintillator

    Directory of Open Access Journals (Sweden)

    F. de Notaristefani

    2002-04-01

    Full Text Available Scintillation properties of a Ce-doped yttrium aluminium oxide perovskite monocrystal optically coupled to a Hamamatsu H5784 photomultiplier are analyzed with a standard bialkali photocathode for radon and radon daughters gamma-ray spectrometry. Tests in water up to 100°C and in acidic solutions of HCl (37%, H2SO4 (48% and HNO3 (65% were performed to simulate environments of geophysical interest, such as geothermal and volcanic areas. Comparative measurements with standard radon sources provided by the National Institute for Metrology of Ionizing Radiations (ENEA confirm the non-hygroscopic properties of the scintillator and small dependence of the light yield on temperature and HNO3.The Ce-doped yttrium aluminum oxide perovskite monocrystal shows high response stability for radon gamma-ray spectrometry in environments with large temperature gradients and high acid concentrations.

  11. The application of the barrier-type anodic oxidation method to thickness testing of aluminum films

    Science.gov (United States)

    Chen, Jianwen; Yao, Manwen; Xiao, Ruihua; Yang, Pengfei; Hu, Baofu; Yao, Xi

    2014-09-01

    The thickness of the active metal oxide film formed from a barrier-type anodizing process is directly proportional to its formation voltage. The thickness of the consumed portion of the metal film is also corresponding to the formation voltage. This principle can be applied to the thickness test of the metal films. If the metal film is growing on a dielectric substrate, when the metal film is exhausted in an anodizing process, because of the high electrical resistance of the formed oxide film, a sudden increase of the recorded voltage during the anodizing process would occur. Then, the thickness of the metal film can be determined from this voltage. As an example, aluminum films are tested and discussed in this work. This method is quite simple and is easy to perform with high precision.

  12. Hydrogen plasma treatment for improved conductivity in amorphous aluminum doped zinc tin oxide thin films

    Directory of Open Access Journals (Sweden)

    M. Morales-Masis

    2014-09-01

    Full Text Available Improving the conductivity of earth-abundant transparent conductive oxides (TCOs remains an important challenge that will facilitate the replacement of indium-based TCOs. Here, we show that a hydrogen (H2-plasma post-deposition treatment improves the conductivity of amorphous aluminum-doped zinc tin oxide while retaining its low optical absorption. We found that the H2-plasma treatment performed at a substrate temperature of 50 °C reduces the resistivity of the films by 57% and increases the absorptance by only 2%. Additionally, the low substrate temperature delays the known formation of tin particles with the plasma and it allows the application of the process to temperature-sensitive substrates.

  13. Anodic aluminum oxide with fine pore size control for selective and effective particulate matter filtering

    Science.gov (United States)

    Zhang, Su; Wang, Yang; Tan, Yingling; Zhu, Jianfeng; Liu, Kai; Zhu, Jia

    2016-07-01

    Air pollution is widely considered as one of the most pressing environmental health issues. Particularly, atmospheric particulate matters (PM), a complex mixture of solid or liquid matter suspended in the atmosphere, are a harmful form of air pollution due to its ability to penetrate deep into the lungs and blood streams, causing permanent damages such as DNA mutations and premature death. Therefore, porous materials which can effectively filter out particulate matters are highly desirable. Here, for the first time, we demonstrate that anodic aluminum oxide with fine pore size control fabricated through a scalable process can serve as effective and selective filtering materials for different types of particulate matters (such as PM2.5, PM10). Combining selective and dramatic filtering effect, fine pore size control and a scalable process, this type of anodic aluminum oxide templates can potentially serve as a novel selective filter for different kinds of particulate matters, and a promising and complementary solution to tackle this serious environmental issue.

  14. Barrier layer non-uniformity effects in anodized aluminum oxide nanopores on ITO substrates

    International Nuclear Information System (INIS)

    Nanoporous anodic aluminum oxide (AAO) has been used widely as a template for device fabrication. In many nanostructured electro-optical device designs, AAO grown on an ITO substrate is the desired configuration. However, a residual thin aluminum oxide barrier layer between ITO and the AAO pores remains and process non-uniformities during the template fabrication can cause serious problems in the quality of nanowires deposited later in these pores. It was observed that in many templates, even the pores closest to each other could have their barrier layer thicknesses differ by as much as 10-20 nm. In this paper, causes and remedies for this non-uniformity are investigated, including the effects of a thin Ti interlayer inserted between the ITO and AAO. Templates with different Ti layer thickness and annealing conditions were compared. Mechanisms for the formation of voids beneath the barrier layer were analyzed and studied experimentally. Reactive ion etch (RIE) was found to be the preferred method to mitigate process non-uniformities. Using the above methods, barrier-free AAO templates on ITO substrates were obtained; their thicknesses ranged from 200 to 1000 nm. The characteristics of CdS nanowires electrodeposited into the initial templates with non-uniform barrier layer thicknesses and into the processed, barrier-free templates were compared.

  15. Analysis of anti-condensation mechanism on superhydrophobic anodic aluminum oxide surface

    International Nuclear Information System (INIS)

    Wetting theory about superhydrophobic surfaces reveals that hydrophobicity of surfaces has great relationship with surface roughness and surface free energy. Adopt electrochemical plus fluorine silane modified method to prepare superhydrophobic surface on anodic aluminum oxide surface, which not only enhances surface roughness, but also reduces surface free energy, even the static contact angle can reach 159.2° and anti-condensation is authenticated. Based on the experimental findings, analyze the reason of anti-condensation on superhydrophobic surfaces: one is that the density of droplets formed on superhydrophobic surfaces is low and the number of droplets is little; the other is bigger static contact angle and smaller rolling angle on superhydrophobic surfaces make droplets easy to detach on smaller tilt angle. This research can solve some condensation problems of equipment using in HVAC systems, such as heat exchangers in air conditioning system, cold radiation boards, air supply outlets, and so on. Highlights: • Prepare superhydrophobic surface on anodic aluminum oxide surface. • Analyze the reason of anti-condensation on superhydrophobic surfaces. • The density of droplets formed on superhydrophobic surfaces is low. • Droplets on superhydrophobic surfaces are easy to detach. • This research can solve some problems of equipment using in HVAC systems

  16. Characterization of lipid bilayer formation in aligned nanoporous aluminum oxide nanotube arrays.

    Science.gov (United States)

    Karp, Ethan S; Newstadt, Justin P; Chu, Shidong; Lorigan, Gary A

    2007-07-01

    Aligning lipid bilayers in nanoporous anodized aluminum oxide (AAO) is a new method to help study membrane proteins by electron paramagnetic resonance (EPR) and solid-state nuclear magnetic resonance (NMR) spectroscopic methods. The ability to maintain hydration, sample stability, and compartmentalization over long periods of time, and to easily change solvent composition are major advantages of this new method. To date, 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) has been the only phospholipid used for membrane protein studies with AAO substrates. The different properties of lipids with varying chain lengths require modified sample preparation procedures to achieve well formed bilayers within the lining of the AAO substrates. For the first time, the current study presents a simple methodology to incorporate large quantities of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC), DMPC, and 1,2-dipalmitoyl-3-sn-phosphatidylcholine (DPPC) phospholipids inside AAO substrate nanopores of varying sizes. (2)H and (31)P solid-state NMR were used to confirm the alignment of each lipid and compare the efficiency of alignment. This study is the first step in standardizing the use of AAO substrates as a tool in NMR and EPR and will be useful for future structural studies of membrane proteins. Additionally, the solid-state NMR data suggest possible applications of nanoporous aluminum oxide in future vesicle fusion studies. PMID:17482492

  17. Polymer/Iron Oxide Nanoparticle Composites—A Straight Forward and Scalable Synthesis Approach

    OpenAIRE

    Jens Sommertune; Abhilash Sugunan; Anwar Ahniyaz; Rebecca Stjernberg Bejhed; Anna Sarwe; Christer Johansson; Christoph Balceris; Frank Ludwig; Oliver Posth; Andrea Fornara

    2015-01-01

    Magnetic nanoparticle systems can be divided into single-core nanoparticles (with only one magnetic core per particle) and magnetic multi-core nanoparticles (with several magnetic cores per particle). Here, we report multi-core nanoparticle synthesis based on a controlled precipitation process within a well-defined oil in water emulsion to trap the superparamagnetic iron oxide nanoparticles (SPION) in a range of polymer matrices of choice, such as poly(styrene), poly(lactid acid), poly(methyl...

  18. New roots to formation of nanostructures on glass surface through anodic oxidation of sputtered aluminum

    Directory of Open Access Journals (Sweden)

    Satoru Inoue, Song-Zhu Chu, Kenji Wada, Di Li and Hajime Haneda

    2003-01-01

    Full Text Available New processes for the preparation of nanostructure on glass surfaces have been developed through anodic oxidation of sputtered aluminum. Aluminum thin film sputtered on a tin doped indium oxide (ITO thin film on a glass surface was converted into alumina by anodic oxidation. The anodic alumina gave nanometer size pore array standing vertically on the glass surface. Kinds of acids used in the anodic oxidation changed the pore size drastically. The employment of phosphoric acid solution gave several tens nanometer size pores. Oxalic acid cases produced a few tens nanometer size pores and sulfuric acid solution provided a few nanometer size pores. The number of pores in a unit area could be changed with varying the applied voltage in the anodization and the pore sizes could be increased by phosphoric acid etching. The specimen consisting of a glass substrate with the alumina nanostructures on the surface could transmit UV and visible light. An etched specimen was dipped in a TiO2 sol solution, resulting in the impregnation of TiO2 sol into the pores of alumina layer. The TiO2 sol was heated at ~400 °C for 2 h, converting into anatase phase TiO2. The specimens possessing TiO2 film on the pore wall were transparent to the light in UV–Visible region. The electro deposition technique was applied to the introduction of Ni metal into pores, giving Ni nanorod array on the glass surface. The removal of the barrier layer alumina at the bottom of the pores was necessary to attain smooth electro deposition of Ni. The photo catalytic function of the specimens possessing TiO2 nanotube array was investigated in the decomposition of acetaldehyde gas under the irradiation of UV light, showing that the rate of the decomposition was quite large.

  19. Photoluminescence blue shift of indium phosphide nanowire networks with aluminum oxide coating

    Energy Technology Data Exchange (ETDEWEB)

    Fryauf, David M.; Zhang, Junce; Norris, Kate J.; Diaz Leon, Juan J.; Oye, Michael M.; Kobayashi, Nobuhiko P. [Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, University of California, Santa Cruz, CA (United States); Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA (United States); NASA Ames Research Center, Moffett Field, CA (United States); Wei, Min [Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA (United States); School of Micro-Electronics and Solid-Electronics, University of Electronic Science and Technology of China, Chengdu (China)

    2014-07-15

    This paper describes our finding that optical properties of semiconductor nanowires were modified by depositing a thin layer of metal oxide. Indium phosphide nanowires were grown by metal organic chemical vapor deposition on silicon substrates with gold catalyst resulting in three-dimensional nanowire networks, and optical properties were obtained from the collective nanowire networks. The networks were coated with an aluminum oxide thin film deposited by plasma-enhanced atomic layer deposition. We studied the dependence of the peak wavelength of photoluminescence spectra on the thickness of the oxide coatings. A continuous blue shift in photoluminescence spectra was observed when the thickness of the oxide coating was increased. The observed blue shift is attributed to the Burstein-Moss effect due to increased carrier concentration in the nanowire cores caused by repulsion from intrinsic negative fixed charges located at the inner oxide surface. Samples were further characterized by scanning electron microscopy, Raman spectroscopy, transmission electron microscopy, and selective area diffractometry to better understand the physical mechanisms for the blue shift. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Photoelectrode Characteristics of Partially Hydrolyzed Aluminum Phthalocyanine Chloride/Fullerene C60 Composite Nanoparticles Working in a Water Phase

    Directory of Open Access Journals (Sweden)

    Shuai Zhang

    2012-09-01

    Full Text Available Photoelectrochemical measurements were used to study the photoelectrode characteristics of composite nanoparticles composed of fullerene C60 and partially hydrolyzed aluminum phthalocyanine chloride (AlPc. In cyclic voltammetry measurements, the electrodes coated with the composite nanoparticles were found to have photoanodic [electron donor: 2-mercaptoethanol (ME] and photocathodic (electron acceptor: O2 characteristics similar to those of the vapor-deposited p/n junction electrode. Their photoanodic features were further investigated with respect to the transient photocurrent response to light irradiation and the dependence on ME concentration (under potentiostatic conditions, from which it was noted that there was a decrease in the initial spiky photocathodic current and saturation of the steady-state photoanodic current at a higher ME concentration. Thus, the reaction kinetics was probably dominated by charge transport process. Moreover, external and internal quantum efficiency spectrum measurements indicated that the composite nanoparticles responded to the full spectrum of visible light ( < 880 nm for both the photoanodic and photocathodic current. The present research will assist comprehension of photocatalytic behavior of the composite nanoparticles.

  1. Structural and magnetic properties of core-shell iron-iron oxide nanoparticles

    DEFF Research Database (Denmark)

    Kuhn, Luise Theil; Bojesen, A.; Timmermann, L.;

    2002-01-01

    We present studies of the structural and magnetic properties of core-shell iron-iron oxide nanoparticles. alpha-Fe nanoparticles were fabricated by sputtering and subsequently covered with a protective nanocrystalline oxide shell consisting of either maghaemite (gamma-Fe2O3) or partially oxidized...

  2. Numerical modeling of the dispersion of ceramic nanoparticles during ultrasonic processing of aluminum-based nanocomposites

    Directory of Open Access Journals (Sweden)

    Daojie Zhang

    2014-10-01

    The modeling parametric study includes the effects of the fluid flow, the ultrasonic probe location, nanoparticle size distribution, and initial location where the nanoparticles are released into the molten alloy. It was determined that the nanoparticles can be distributed quickly and uniformly into the molten 6061 alloy.

  3. Pharmacokinetics, tissue distribution, and excretion of zinc oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Baek M

    2012-06-01

    Full Text Available Miri Baek,1,* Hae-Eun Chung,1,* Jin Yu,1,* Jung-A Lee,1 Tae-Hyun Kim,2 Jae-Min Oh,2 Won-Jae Lee,3 Seung-Min Paek,3 Jong Kwon Lee,4 Jayoung Jeong, 4 Jin-Ho Choy,5 Soo-Jin Choi1 1Department of Food Science and Technology, Seoul Women's University, Seoul, 2Department of Chemistry and Medical Chemistry, College of Science and Technology, Yonsei University, Wonju, Gangwondo; 3Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, Taegu, 4Toxicological Research Division, National Institute of Food and Drug Safety Evaluation, Chungchungbuk-do, 5Center for Intelligent Nano-Bio Materials, Department of Bioinspired Science and Department of Chemistry and Nano Science, Ewha Womans University, Seoul, Republic of Korea*These authors contributed equally to this workBackground: This study explored the pharmacokinetics, tissue distribution, and excretion profile of zinc oxide (ZnO nanoparticles with respect to their particle size in rats.Methods: Two ZnO nanoparticles of different size (20 nm and 70 nm were orally administered to male and female rats, respectively. The area under the plasma concentration-time curve, tissue distribution, excretion, and the fate of the nanoparticles in organs were analyzed.Results: The plasma zinc concentration of both sizes of ZnO nanoparticles increased during the 24 hours after administration in a dose-dependent manner. They were mainly distributed to organs such as the liver, lung, and kidney within 72 hours without any significant difference being found according to particle size or rat gender. Elimination kinetics showed that a small amount of ZnO nanoparticles was excreted via the urine, while most of nanoparticles were excreted via the feces. Transmission electron microscopy and x-ray absorption spectroscopy studies in the tissues showed no noticeable ZnO nanoparticles, while new Zn-S bonds were observed in tissues.Conclusion: ZnO nanoparticles of different size were not easily

  4. Synthesis, purification and assembly of gold and iron oxide nanoparticles

    Science.gov (United States)

    Qiu, Penghe

    , 6 & 7), nanoparticles were assembled into three different hierachical structures through both template-assisted and template-free approaches. In the template-assisted assembly, gold nanorods were aligned into ordered 1D linear pattern by using soft biological filamentous, namely bacteria flagella, as templates. Two different ways of assembling nanorods onto flagella were investigated. In another study, a highly commercialized polymer, polyvinylpyrrolidone (PVP), was discovered for the first time to be able to self-assemble into branched hollow fibers. Based on this discovery, two approaches (one through direct deposition of silica onto the PVP aggregate and the other through co-assembly of PVP covered gold nanoparticles with free PVP molecules) by which the self-assembly behavior of PVP could be exploited to template the formation of branched hollow inorganic fibers were demonstrated. In the template-free assembly, a general method for assembling nanoparticle into clusters (NPCs) in an oil-in-water emulsion system was investigated. Detailed studies on the mechanism of formation of NPCs structure, optimized conditions, scalable production and surface chemistry manipulation were carried out. Besides, comparison of the properties of individual and clustered iron oxide nanoparticles was conducted. It was discovered that due to their collective properties, NPCs are more responsive to an external magnetic field and can potentially serve as better contrast enhancement agents than individually dispersed magnetic NPs in Magnetic Resonance Imaging (MRI).

  5. Nanostructured Metal Oxides And Mixed Metal Oxides, Methods Of Making These Nanoparticles, And Methods Of Their Use

    KAUST Repository

    Polshettiwar, Vivek

    2013-04-11

    Embodiments of the present disclosure provide for nanoparticles, methods of making nanoparticles, methods of using the nanoparticles, and the like. Nanoparticles of the present disclosure can have a variety of morphologies, which may lead to their use in a variety of technologies and processes. Nanoparticles of the present may be used in sensors, optics, mechanics, circuits, and the like. In addition, nanoparticles of the present disclosure may be used in catalytic reactions, for CO oxidation, as super-capacitors, in hydrogen storage, and the like.

  6. Fabrication of high quality anodic aluminum oxide (AAO) on low purity aluminum—A comparative study with the AAO produced on high purity aluminum

    International Nuclear Information System (INIS)

    Highlights: • Nanoporous alumina was fabricated by anodization in sulfuric acid solution with glycol. • The AAO manufacturing on low- and high-purity Al was compared. • The pores size was ranging between 30 and 50 nm. • No difference in the quality of the AAO fabricated on both Al types was observed. • The current vs. anodization time curves were recorded. -- Abstract: In this work the quality, arrangement, composition, and regularity of nanoporous AAO formed on the low-purity (AA1050) and high-purity aluminum during two-step anodization in a mixture of sulfuric acid solution (0.3 M), water and glycol (3:2, v/v), at various voltages (15, 20, 25, 30, 35 V) and at temperature of −1 °C, are investigated. The electrochemical conditions have allowed to obtain pores with the size ranging from 30 to 50 nm, which are much larger than those usually obtained by anodization in a pure sulfuric acid solution (<20 nm). The mechanism of the AAO growth is discussed. It was found that with the increase of applied anodizing voltage a number of incorporated sulfate ions in the aluminum oxide matrix increases, which was connected with the appearance of an unusual area in the current vs. time curves. On the surface of anodizing low- and high-purity aluminum, the formation of hillocks was observed, which was associated with the sulfate ions incorporation. The sulfate ions are replacing the oxygen atom/atoms in the AAO amorphous crystal structure and, consequently, the AAO template swells, the oxide cracks and uplifts causing the formation of hillocks. The same mechanism occurs for both low- and high-purity aluminum. Nanoporous AAO characterized by a very high regularity, not registered previously for low purity aluminum, was obtained. Furthermore, no significant difference in the regularity ratio between the AAO obtained on low- and high-purity aluminum, was observed. The electrochemical conditions applied in this study can be, thus, used for the fabrication of high quality

  7. A Prediction Study on Oxidation of Aluminum Alloy Cladding of U3Si2-Al Fuel Plate

    International Nuclear Information System (INIS)

    U3Si2-Al dispersion fuel with aluminum alloy cladding will be used for the Jordan Research and Training Reactor (JRTR). Aluminum alloy cladding undergoes corrosion at slow rates under operational status. This causes thinning of the cladding walls and impairs heat transfer to the coolant. Predictions of the aluminum oxide thickness of the fuel cladding and the maximum temperature difference across the oxide film are needed for reliability evaluation based on the design criteria and limits which prohibit spallation of oxide film. In this work, several oxide thickness prediction models were compared with the measured data of in-pile test results from RERTR program. Moreover, specific parametric studies and a preliminary prediction of the aluminum alloy oxidation using the latest model were performed for JRTR fuel. According to the current JRTR fuel management scheme and operation strategy for 5 MW power, fresh fuel is discharged after 900 effective full power days (EFPD), which is too long a span to predict oxidation properly without an elaborate model. The latest model developed by Kim et al. is in good agreement with the recent in-pile test data as well as with the out-of-pile test data available in the literature, and is one of the best predictors for the oxidation of aluminum alloy cladding in various operating condition. Accordingly, this model was chosen for estimating the oxide film thickness. Through the preliminarily evaluation, water pH level is to be controlled lower than 6.2 for the conservativeness in the case of including the effect of anticipated operational occurrences and the spent fuel residence time in the storage rack after discharging. (author)

  8. Concentration-dependent toxicity of iron oxide nanoparticles mediated by increased oxidative stress

    Directory of Open Access Journals (Sweden)

    Saba Naqvi

    2010-11-01

    Full Text Available Saba Naqvi1, Mohammad Samim2, MZ Abdin3, Farhan Jalees Ahmed4, AN Maitra5, CK Prashant6, Amit K Dinda61Faculty of Engineering and Interdisciplinary Sciences, 2Department of Chemistry, 3Department of Biotechnology, Faculty of Science, 4Department of Pharmaceutics, Faculty of Pharmacy, Jamia Hamdard, Hamdard University, 5Department of Chemistry, University of Delhi, 6Department of Pathology, All India Institute of Medical Sciences, New Delhi, IndiaAbstract: Iron oxide nanoparticles with unique magnetic properties have a high potential for use in several biomedical, bioengineering and in vivo applications, including tissue repair, magnetic resonance imaging, immunoassay, drug delivery, detoxification of biologic fluids, cell sorting, and hyperthermia. Although various surface modifications are being done for making these nonbiodegradable nanoparticles more biocompatible, their toxic potential is still a major concern. The current in vitro study of the interaction of superparamagnetic iron oxide nanoparticles of mean diameter 30 nm coated with Tween 80 and murine macrophage (J774 cells was undertaken to evaluate the dose- and time-dependent toxic potential, as well as investigate the role of oxidative stress in the toxicity. A 15–30 nm size range of spherical nanoparticles were characterized by transmission electron microscopy and zeta sizer. MTT assay showed >95% viability of cells in lower concentrations (25–200 µg/mL and up to three hours of exposure, whereas at higher concentrations (300–500 µg/mL and prolonged (six hours exposure viability reduced to 55%–65%. Necrosis-apoptosis assay by propidium iodide and Hoechst-33342 staining revealed loss of the majority of the cells by apoptosis. H2DCFDDA assay to quantify generation of intracellular reactive oxygen species (ROS indicated that exposure to a higher concentration of nanoparticles resulted in enhanced ROS generation, leading to cell injury and death. The cell membrane injury

  9. Synthesis of Functionalized Iron Oxide Nanoparticle with Amino Pyridine Moiety and Studies on Their Catalytic Behavior

    OpenAIRE

    Girija, D.; Naik, Halehatty S. Bhojya; Kumar, B. Vinay; Sudhamani, C. N.

    2011-01-01

    Aim: The main objective of this paper is to study the synthesis of functionalized iron oxide nanoparticle and its reactivity towards chromene synthesis Study design: Functionalized iron oxide nanoparticle study. Place and duration of study: Department of Studies and Research in Industrial Chemistry, School of Chemical Sciences, Kuvempu University, Shankaraghatta, between December 2009 and July 2010. Methodology: This paper describes synthesis of stable functionalized iron oxide nanoparticles ...

  10. Molecular Responses of Mouse Macrophages to Copper and Copper Oxide Nanoparticles Inferred from Proteomic Analyses*

    OpenAIRE

    Triboulet, Sarah; Aude-Garcia, Catherine; Carrière, Marie; Diemer, Hélène; Proamer, Fabienne; Habert, Aurélie; Chevallet, Mireille; Collin-Faure, Véronique; Strub, Jean-Marc; Hanau, Daniel; Van Dorsselaer, Alain; Herlin-Boime, Nathalie; Rabilloud, Thierry

    2013-01-01

    The molecular responses of macrophages to copper-based nanoparticles have been investigated via a combination of proteomic and biochemical approaches, using the RAW264.7 cell line as a model. Both metallic copper and copper oxide nanoparticles have been tested, with copper ion and zirconium oxide nanoparticles used as controls. Proteomic analysis highlighted changes in proteins implicated in oxidative stress responses (superoxide dismutases and peroxiredoxins), glutathione biosynthesis, the a...

  11. Mussel-Inspired Polydopamine Coated Iron Oxide Nanoparticles for Biomedical Application

    OpenAIRE

    Xiangling Gu; Yancong Zhang; Hanwen Sun; Xinfeng Song; Chunhua Fu; Pingxuan Dong

    2015-01-01

    Mussel-inspired polydopamine (PDA) coated iron oxide nanoparticles have served as a feasible, robust, and functional platform for various biomedical applications. However, there is scarcely a systemic paper reviewed about such functionalising nanomaterials to date. In this review, the synthesis of iron oxide nanoparticles, the mechanism of dopamine self-oxidation, the interaction between iron oxide and dopamine, and the functionality and the safety assessment of dopamine modified iron oxide n...

  12. Murine pulmonary responses after sub-chronic exposure to aluminum oxide-based nanowhiskers

    Directory of Open Access Journals (Sweden)

    Adamcakova-Dodd Andrea

    2012-06-01

    Full Text Available Abstract Background Aluminum oxide-based nanowhiskers (AO nanowhiskers have been used in manufacturing processes as catalyst supports, flame retardants, adsorbents, or in ceramic, metal and plastic composite materials. They are classified as high aspect ratio nanomaterials. Our aim was to assess in vivo toxicity of inhaled AO nanowhisker aerosols. Methods Primary dimensions of AO nanowhiskers specified by manufacturer were 2–4 nm x 2800 nm. The aluminum content found in this nanomaterial was 30% [mixed phase material containing Al(OH3 and AlOOH]. Male mice (C57Bl/6 J were exposed to AO nanowhiskers for 4 hrs/day, 5 days/wk for 2 or 4 wks in a dynamic whole body exposure chamber. The whiskers were aerosolized with an acoustical dry aerosol generator that included a grounded metal elutriator and a venturi aspirator to enhance deagglomeration. Average concentration of aerosol in the chamber was 3.3 ± 0.6 mg/m3 and the mobility diameter was 150 ± 1.6 nm. Both groups of mice (2 or 4 wks exposure were necropsied immediately after the last exposure. Aluminum content in the lung, heart, liver, and spleen was determined. Pulmonary toxicity assessment was performed by evaluation of bronchoalveolar lavage (BAL fluid (enumeration of total and differential cells, total protein, activity of lactate dehydrogenase [LDH] and cytokines, blood (total and differential cell counts, lung histopathology and pulmonary mechanics. Results Following exposure, mean Al content of lungs was 0.25, 8.10 and 15.37 μg/g lung (dry wt respectively for sham, 2 wk and 4 wk exposure groups. The number of total cells and macrophages in BAL fluid was 2-times higher in animals exposed for 2 wks and 6-times higher in mice exposed for 4 wks, compared to shams (p p  Conclusions Sub-chronic inhalation exposures to aluminum-oxide based nanowhiskers induced increased lung macrophages, but no inflammatory or toxic responses were observed.

  13. High stability mechanisms of quinary indium gallium zinc aluminum oxide multicomponent oxide films and thin film transistors

    International Nuclear Information System (INIS)

    Quinary indium gallium zinc aluminum oxide (IGZAO) multicomponent oxide films were deposited using indium gallium zinc oxide (IGZO) target and Al target by radio frequency magnetron cosputtering system. An extra carrier transport pathway could be provided by the 3 s orbitals of Al cations to improve the electrical properties of the IGZO films, and the oxygen instability could be stabilized by the strong Al-O bonds in the IGZAO films. The electron concentration change and the electron mobility change of the IGZAO films for aging time of 10 days under an air environment at 40 °C and 75% humidity were 20.1% and 2.4%, respectively. The experimental results verified the performance stability of the IGZAO films. Compared with the thin film transistors (TFTs) using conventional IGZO channel layer, in conducting the stability of TFTs with IGZAO channel layer, the transconductance gm change, threshold voltage VT change, and the subthreshold swing S value change under the same aging condition were improved to 7.9%, 10.5%, and 14.8%, respectively. Furthermore, the stable performances of the IGZAO TFTs were also verified by the positive gate bias stress. In this research, the quinary IGZAO multicomponent oxide films and that applied in TFTs were the first studied in the literature

  14. Synthesis of tungsten oxide, silver, and gold nanoparticles by radio frequency plasma in water

    International Nuclear Information System (INIS)

    Highlights: •RF plasma in water was used for nanoparticle synthesis. •Nanoparticles were produced from erosion of metallic electrode. •Rectangular and spherical tungsten oxide nanoparticles were produced. •No oxidations of the silver and gold spherical nanoparticles were produced. -- Abstract: A process for synthesis of nanoparticles using plasma in water generated by a radio frequency of 27.12 MHz is proposed. Tungsten oxide, silver, and gold nanoparticles were produced at 20 kPa through erosion of a metallic electrode exposed to plasma. Characterization of the produced nanoparticles was carried out by XRD, absorption spectrum, and TEM. The nanoparticle sizes were compared with those produced by a similar technique using plasma in liquid

  15. Oxidative Dissolution of Silver Nanoparticles by Chlorine: Implications to Silver Nanoparticle Fate and Toxicity.

    Science.gov (United States)

    Garg, Shikha; Rong, Hongyan; Miller, Christopher J; Waite, T David

    2016-04-01

    The kinetics of oxidative dissolution of silver nanoparticles (AgNPs) by chlorine is investigated in this work, with results showing that AgNPs are oxidized in the presence of chlorine at a much faster rate than observed in the presence of dioxygen and/or hydrogen peroxide. The oxidation of AgNPs by chlorine occurs in air-saturated solution in stoichiometric amounts with 2 mol of AgNPs oxidized for each mole of chlorine added. Dioxygen plays an important role in OCl(-)-mediated AgNP oxidation, especially at lower OCl(-) concentrations, with the mechanism shifting from stoichiometric oxidation of AgNPs by OCl(-) in the presence of dioxygen to catalytic removal of OCl(-) by AgNPs in the absence of dioxygen. These results suggest that the presence of chlorine will mitigate AgNP toxicity by forming less-reactive AgCl(s) following AgNP oxidation, although the disinfection efficiency of OCl(-) may not be significantly impacted by the presence of AgNPs because a chlorine-containing species is formed on OCl(-) decay that has significant oxidizing capacity. Our results further suggest that the antibacterial efficacy of nanosilver particles embedded on fabrics may be negated when treated with detergents containing strong oxidants, such as chlorine. PMID:26986484

  16. Oxidation Behavior of In-Flight Molten Aluminum Droplets in the Twin-Wire Electric Arc Thermal Spray Process

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Brian G. Williams

    2005-05-01

    This paper examines the in-flight oxidation of molten aluminum sprayed in air using the twin-wire electric arc (TWEA) thermal spray process. The oxidation reaction of aluminum in air is highly exothermic and is represented by a heat generation term in the energy balance. Aerodynamic shear at the droplet surface enhances the amount of in-flight oxidation by: (1) promoting entrainment and mixing of the surface oxides within the droplet, and (2) causing a continuous heat generation effect that increases droplet temperature over that of a droplet without internal circulation. This continual source of heat input keeps the droplets in a liquid state during flight. A linear rate law based on the Mott-Cabrera theory was used to estimate the growth of the surface oxide layer formed during droplet flight. The calculated oxide volume fraction of an average droplet at impact agrees well with the experimentally determined oxide content for a typical TWEA-sprayed aluminum coating, which ranges from 3.3 to 12.7%. An explanation is provided for the elevated, nearly constant surface temperature (~ 2000 oC) of the droplets during flight to the substrate and shows that the majority of oxide content in the coating is produced during flight, rather than after deposition.

  17. Effect of interfacial oxide thickness on the photocatalytic activity of magnetron-sputtered TiO2coatings on aluminum substrate

    DEFF Research Database (Denmark)

    Daviðsdóttir, Svava; Petit, Jean-Pierre; Shabadi, Rajashekhara;

    2015-01-01

    measurements showed a maximum UV-light absorption by titanium dioxide occurring slightly prior to the energy of the maximum photocurrent. The photocurrent of titanium dioxide decreases with increasing thickness of the aluminum oxide interface layer. Aluminum oxide acts as an insulator; disfavoring the electron...

  18. Effect of interfacial oxide thickness on the photocatalytic activity of magnetron-sputtered TiO2 coatings on aluminum substrate

    DEFF Research Database (Denmark)

    Daviðsdóttir, Svava; Petit, Jean-Pierre; Shabadi, Rajashekhara;

    2015-01-01

    measurements showed a maximum UV-light absorption by titanium dioxide occurring slightly prior to the energy of the maximum photocurrent. The photocurrent of titanium dioxide decreases with increasing thickness of the aluminum oxide interface layer. Aluminum oxide acts as an insulator; disfavoring the electron...

  19. Geant4 simulation of zinc oxide nanowires in anodized aluminum oxide template as a low energy X-ray scintillator detector

    International Nuclear Information System (INIS)

    In this work, ZnO nanowires in anodized aluminum oxide nanoporous template are proposed as an architecture for development of new generation of scintillator based X-ray imagers. The optical response of crystalline ordered ZnO nanowire arrays in porous anodized aluminum oxide template under 20 keV X-ray illumination is simulated using the Geant4 Monte Carlo code. The results show that anodized aluminum oxide template has a special impact as a light guide to conduct the optical photons induced by X-ray toward the detector thickness and to decrease the light scattering in detector volume. This inexpensive and effective method can significantly improve the spatial resolution in scintillator based X-ray imagers, especially in medical applications.

  20. X-ray photoelectron spectroscopy study of the stability of Fomblin Z25 on the native oxide of aluminum

    Science.gov (United States)

    Herrera-Fierro, Pilar; Pepper, Stephen V.; Jones, William R.

    1992-01-01

    Thin films of Fomblin Z25, a perfluoropolyalkylether lubricant, were vapor deposited onto clean, oxidized aluminum, and onto sapphire surfaces, and their behavior at different temperatures was studied using X-ray photoelectron spectroscopy and temperature desorption spectroscopy (TDS). The interfacial fluid molecules decompose on the native oxide at room temperature, and continue to decompose at elevated temperatures, as previous studies had shown to occur on the clean metal. TDS indicated that different degradation mechanisms were operative for clean and oxidized aluminum. On sapphire substrates, no reaction was observed at room temperature. The native oxide of aluminum is neither passive nor protective towards Fomblin Z25. At higher temperatures (150 C), degradation of the polymer on sapphire produced a debris layer at the interface with a chemical composition similar to the one formed on aluminum oxide. Rubbing a Fomblin film on a single crystal sapphire also induced the decomposition of the lubricant in contact with the interface and the formation of a debris layer.

  1. A Conductometric Indium Oxide Semiconducting Nanoparticle Enzymatic Biosensor Array

    Directory of Open Access Journals (Sweden)

    Tianhong Cui

    2011-09-01

    Full Text Available We report a conductometric nanoparticle biosensor array to address the significant variation of electrical property in nanomaterial biosensors due to the random network nature of nanoparticle thin-film. Indium oxide and silica nanoparticles (SNP are assembled selectively on the multi-site channel area of the resistors using layer-by-layer self-assembly. To demonstrate enzymatic biosensing capability, glucose oxidase is immobilized on the SNP layer for glucose detection. The packaged sensor chip onto a ceramic pin grid array is tested using syringe pump driven feed and multi-channel I–V measurement system. It is successfully demonstrated that glucose is detected in many different sensing sites within a chip, leading to concentration dependent currents. The sensitivity has been found to be dependent on the channel length of the resistor, 4–12 nA/mM for channel lengths of 5–20 µm, while the apparent Michaelis-Menten constant is 20 mM. By using sensor array, analytical data could be obtained with a single step of sample solution feeding. This work sheds light on the applicability of the developed nanoparticle microsensor array to multi-analyte sensors, novel bioassay platforms, and sensing components in a lab-on-a-chip.

  2. A conductometric indium oxide semiconducting nanoparticle enzymatic biosensor array.

    Science.gov (United States)

    Lee, Dongjin; Ondrake, Janet; Cui, Tianhong

    2011-01-01

    We report a conductometric nanoparticle biosensor array to address the significant variation of electrical property in nanomaterial biosensors due to the random network nature of nanoparticle thin-film. Indium oxide and silica nanoparticles (SNP) are assembled selectively on the multi-site channel area of the resistors using layer-by-layer self-assembly. To demonstrate enzymatic biosensing capability, glucose oxidase is immobilized on the SNP layer for glucose detection. The packaged sensor chip onto a ceramic pin grid array is tested using syringe pump driven feed and multi-channel I-V measurement system. It is successfully demonstrated that glucose is detected in many different sensing sites within a chip, leading to concentration dependent currents. The sensitivity has been found to be dependent on the channel length of the resistor, 4-12 nA/mM for channel lengths of 5-20 μm, while the apparent Michaelis-Menten constant is 20 mM. By using sensor array, analytical data could be obtained with a single step of sample solution feeding. This work sheds light on the applicability of the developed nanoparticle microsensor array to multi-analyte sensors, novel bioassay platforms, and sensing components in a lab-on-a-chip. PMID:22163696

  3. Performance enhancement of polymer solar cells using copper oxide nanoparticles

    Science.gov (United States)

    Wanninayake, Aruna P.; Gunashekar, Subhashini; Li, Shengyi; Church, Benjamin C.; Abu-Zahra, Nidal

    2015-06-01

    Copper oxide (CuO) is a p-type semiconductor with a band gap energy of 1.5 eV, this is close to the ideal energy gap of 1.4 eV required for solar cells to allow good solar spectral absorption. The inherent electrical characteristics of CuO nanoparticles make them attractive candidates for improving the performance of polymer solar cells when incorporated into the active polymer layer. The UV-visible absorption spectra and external quantum efficiency of P3HT/PC70BM solar cells containing different weight percentages of CuO nanoparticles showed a clear enhancement in the photo absorption of the active layer, this increased the power conversion efficiency of the solar cells by 24% in comparison to the reference cell. The short circuit current of the reference cell was found to be 5.234 mA cm-2 and it seemed to increase to 6.484 mA cm-2 in cells containing 0.6 mg of CuO NPs; in addition, the fill factor increased from 61.15% to 68.0%, showing an enhancement of 11.2%. These observations suggest that the optimum concentration of CuO nanoparticles was 0.6 mg in the active layer. These significant findings can be applied to design high-efficiency polymer solar cells containing inorganic nanoparticles.

  4. Performance enhancement of polymer solar cells using copper oxide nanoparticles

    International Nuclear Information System (INIS)

    Copper oxide (CuO) is a p-type semiconductor with a band gap energy of 1.5 eV, this is close to the ideal energy gap of 1.4 eV required for solar cells to allow good solar spectral absorption. The inherent electrical characteristics of CuO nanoparticles make them attractive candidates for improving the performance of polymer solar cells when incorporated into the active polymer layer. The UV-visible absorption spectra and external quantum efficiency of P3HT/PC70BM solar cells containing different weight percentages of CuO nanoparticles showed a clear enhancement in the photo absorption of the active layer, this increased the power conversion efficiency of the solar cells by 24% in comparison to the reference cell. The short circuit current of the reference cell was found to be 5.234 mA cm−2 and it seemed to increase to 6.484 mA cm−2 in cells containing 0.6 mg of CuO NPs; in addition, the fill factor increased from 61.15% to 68.0%, showing an enhancement of 11.2%. These observations suggest that the optimum concentration of CuO nanoparticles was 0.6 mg in the active layer. These significant findings can be applied to design high-efficiency polymer solar cells containing inorganic nanoparticles. (paper)

  5. Role of aluminum doping on phase transformations in nanoporous titania anodic oxides

    International Nuclear Information System (INIS)

    The role of aluminium doping on anatase to rutile phase transformation of nanoporous titanium oxide films were investigated. For this purpose pure and aluminum doped metal films were deposited on alumina substrates by cathodic arc physical deposition. The nanoporous anodic oxides were prepared by porous anodizing of pure and aluminum doped titanium metallic films in an ethylene glycol + NH4F based electrolyte. Nanoporous amorphous structures with 60–80 nm diameter and 2–4 μm length were formed on the surfaces of alumina substrates. The amorphous undoped and Al-doped TiO2 anodic oxides were heat-treated at different temperatures in the range of 280–720 °C for the investigation of their crystallization behavior. The combined effects of nanoporous structure and Al doping on crystallization behavior of titania were investigated using X-ray diffraction (XRD) and micro Raman analysis. The results indicated that both Al ions incorporated into the TiO2 structure and the nanoporous structure retarded the rutile formation. It was also revealed that presence or absence of metallic film underneath the nanopores has a major contribution to anatase-rutile transformation. - Highlights: • Al-doped TiO2 nanopores were grown on alumina substrates using anodization method. • The crystallization behavior of nanoporous Al-doped TiO2 were investigated. • Al doping into nanoporous TiO2 retarded the anatase-rutile transformation. • Nanostructuring has significant role in controlling rutile formation temperature. • The absence of the metallic film under the nanopores delayed the rutile formation

  6. Role of aluminum doping on phase transformations in nanoporous titania anodic oxides

    Energy Technology Data Exchange (ETDEWEB)

    Bayata, Fatma [Istanbul Bilgi University, Department of Mechanical Engineering, 34060, Eyup, Istanbul (Turkey); Ürgen, Mustafa, E-mail: urgen@itu.edu.tr [Istanbul Technical University, Department of Metallurgical and Materials Engineering, 34469, Maslak, Istanbul (Turkey)

    2015-10-15

    The role of aluminium doping on anatase to rutile phase transformation of nanoporous titanium oxide films were investigated. For this purpose pure and aluminum doped metal films were deposited on alumina substrates by cathodic arc physical deposition. The nanoporous anodic oxides were prepared by porous anodizing of pure and aluminum doped titanium metallic films in an ethylene glycol + NH{sub 4}F based electrolyte. Nanoporous amorphous structures with 60–80 nm diameter and 2–4 μm length were formed on the surfaces of alumina substrates. The amorphous undoped and Al-doped TiO{sub 2} anodic oxides were heat-treated at different temperatures in the range of 280–720 °C for the investigation of their crystallization behavior. The combined effects of nanoporous structure and Al doping on crystallization behavior of titania were investigated using X-ray diffraction (XRD) and micro Raman analysis. The results indicated that both Al ions incorporated into the TiO{sub 2} structure and the nanoporous structure retarded the rutile formation. It was also revealed that presence or absence of metallic film underneath the nanopores has a major contribution to anatase-rutile transformation. - Highlights: • Al-doped TiO{sub 2} nanopores were grown on alumina substrates using anodization method. • The crystallization behavior of nanoporous Al-doped TiO{sub 2} were investigated. • Al doping into nanoporous TiO{sub 2} retarded the anatase-rutile transformation. • Nanostructuring has significant role in controlling rutile formation temperature. • The absence of the metallic film under the nanopores delayed the rutile formation.

  7. Interactions of aluminum with biochars and oxidized biochars: implications for the biochar aging process.

    Science.gov (United States)

    Qian, Linbo; Chen, Baoliang

    2014-01-15

    Interactions of aluminum with primary and oxidized biochars were compared to understand the changes in the adsorption properties of aged biochars. The structural characteristics of rice straw-derived biochars, before and after oxidation by HNO3/H2SO4, were analyzed by element composition, FTIR, and XPS. The adsorption of Al to primary biochars was dominated by binding to inorganic components (such as silicon particles) and surface complexation of oxygen-containing functional groups via esterification reactions. Oxidization (aging) introduced carboxylic functional groups on biochar surfaces, which served as additional binding sites for Al(3+). At pH 2.5-3.5, the Al(3+) binding was significantly greater on oxidized biochars than primary biochars. After loading with Al, the -COOH groups anchored to biochar surfaces were transformed into COO(-) groups, and the negative surface charge diminished, which indicated that Al(3+) coordinated with COO(-). Biochar is suggested as a potential adsorbent for removing Al from acidic soils. PMID:24364719

  8. Thermal and magnetic properties of chitosan-iron oxide nanoparticles.

    Science.gov (United States)

    Soares, Paula I P; Machado, Diana; Laia, César; Pereira, Laura C J; Coutinho, Joana T; Ferreira, Isabel M M; Novo, Carlos M M; Borges, João Paulo

    2016-09-20

    Chitosan is a biopolymer widely used for biomedical applications such as drug delivery systems, wound healing, and tissue engineering. Chitosan can be used as coating for other types of materials such as iron oxide nanoparticles, improving its biocompatibility while extending its range of applications. In this work iron oxide nanoparticles (Fe3O4 NPs) produced by chemical precipitation and thermal decomposition and coated with chitosan with different molecular weights were studied. Basic characterization on bare and chitosan-Fe3O4 NPs was performed demonstrating that chitosan does not affect the crystallinity, chemical composition, and superparamagnetic properties of the Fe3O4 NPs, and also the incorporation of Fe3O4 NPs into chitosan nanoparticles increases the later hydrodynamic diameter without compromising its physical and chemical properties. The nano-composite was tested for magnetic hyperthermia by applying an alternating current magnetic field to the samples demonstrating that the heating ability of the Fe3O4 NPs was not significantly affected by chitosan. PMID:27261762

  9. Biocompatible capped iron oxide nanoparticles for Vibrio cholerae detection

    Science.gov (United States)

    Sharma, Anshu; Baral, Dinesh; Rawat, Kamla; Solanki, Pratima R.; Bohidar, H. B.

    2015-05-01

    We report the studies relating to fabrication of an efficient immunosensor for Vibrio cholerae detection. Magnetite (iron oxide (Fe3O4)) nanoparticles (NPs) have been synthesized by the co-precipitation method and capped by citric acid (CA). These NPs were electrophoretically deposited onto indium-tin-oxide (ITO)-coated glass substrate and used for immobilization of monoclonal antibodies against Vibrio cholerae (Ab) and bovine serum albumin (BSA) for Vibrio cholerae detection using an electrochemical technique. The structural and morphological studies of Fe3O4 and CA-Fe3O4/ITO were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and dynamic light scattering (DLS) techniques. The average crystalline size of Fe3O4, CA-Fe3O4 nanoparticles obtained were about 29 ± 1 nm and 37 ± 1 nm, respectively. The hydrodynamic radius of the nanoparticles was found to be 77.35 nm (Fe3O4) and 189.51 nm (CA-Fe3O4) by DLS measurement. The results of electrochemical response studies of the fabricated BSA/Ab/CA-Fe2O3/ITO immunosensor exhibits a good detection range of 12.5-500 ng mL-1 with a low detection limit of 0.32 ng mL-1, sensitivity 0.03 Ω/ng ml-1 cm-2, and reproducibility more than 11 times.

  10. A chemical strategy to control the shape of oxide nanoparticles

    International Nuclear Information System (INIS)

    A new strategy, epoxide-assisted precipitation route presented in this work, allows the shape control synthesis of Co3O4 nanoparticles. The shape of the nanoparticles is determined by the nature of the precursor cobalt salts (Co(NO3)2 . 6H2O, CoCl2 . 6H2O) used for the preparation of the particles. The different reaction dynamics of the two salts in ethanolic and aqueous solutions with propylene oxide result in precursor particles with different structures, which lead to the formation of oxide nanoparticles with different shapes during the heat treatment. Spherical particles of about 20 nm are obtained from the ethanolic solution of Co(NO3)2 . 6H2O; cubic-shaped particles of about 30 nm can be prepared from the ethanolic solution of CoCl2 . 6H2O; whereas platelet-like particles of more than 100 nm are synthesized from the aqueous solution of the mixture of Co(NO3)2 . 6H2O and CoCl2 . 6H2O.

  11. Catalytic oxidation of carbon monoxide over supported palladium nanoparticles

    Science.gov (United States)

    Soni, Keshav Chand; Krishna, R.; Chandra Shekar, S.; Singh, Beer

    2016-01-01

    Catalytic oxidation of CO with ozone had been studied over Al2O3 and SiO2 supported Pd nanoparticles which was synthesized by two different methods. The polyol method mainly resulted in highly dispersed Pd particles on the support, while the impregnation method resulted in agglomeration Pd particles on the support. Supported Pd nanoparticles synthesized from PdCl2 in the presence of poly ( N-vinylpyrrolidone) (PVP) by chemical reduction. The catalysts were characterized by X-ray diffraction, N2 BET surface area, pore size distributions, CO chemisorption, TEM and H2-temperature programmed reduction. The physico-chemical properties were well correlated with activity data. Characterizations of XRD and TEM show that the surface Pd nanoparticles are highly dispersed over Al2O3 and SiO2. The catalytic activity was dependent upon ozone/CO ratio, contact times, and the reaction temperature. The extent of carbon monoxide oxidation was proportional to the catalytically ozone decomposition. The PVP synthesized Pd/A2O3 catalyst had been found to be highly active for complete CO removal at room temperature. The higher activity of the nanocatalyst was attributed to small particle size and higher dispersion of Pd over support.

  12. Laser ablation synthesis of indium oxide nanoparticles in water

    Energy Technology Data Exchange (ETDEWEB)

    Acacia, N. [Dipartimento di Fisica della Materia e Ingegneria Elettronica, Universita di Messina, Salita Sperone 31, I-98166 Messina (Italy); Barreca, F., E-mail: process@anmresearch.it [Advanced and Nano Materials Research s.r.l., Salita Sperone 31, I-98166 Messina (Italy); Barletta, E.; Spadaro, D.; Curro, G. [Advanced and Nano Materials Research s.r.l., Salita Sperone 31, I-98166 Messina (Italy); Neri, F. [Dipartimento di Fisica della Materia e Ingegneria Elettronica, Universita di Messina, Salita Sperone 31, I-98166 Messina (Italy)

    2010-09-01

    Colloidal solutions of Indium oxide nanoparticles have been produced by means of laser ablation in liquids (LALs) technique by simply irradiating with a second harmonic (532 nm) Nd:YAG laser beam a metallic indium target immersed in distilled water and varying the laser fluence up to 10 J cm{sup -2} and the ablation time up to 120 min. At all the investigated fluences the vaporization process of the indium target is the dominant one. It produces a majority (>80%) of small size (<6 nm) nanoparticles, with a very limited content of larger ones (size between 10 and 20 nm). The amount of particles increases regularly with the ablation time, supporting the scalability of the production technique. The deposited nanoparticles stoichiometry has been verified by both X-ray photoelectron spectroscopy (XPS) and Energy Dispersive X-ray (EDX) analysis. Optical bandgap values of 3.70 eV were determined by UV-vis absorption measurements. All these results confirm the complete oxidation of the ablated material.

  13. Laser ablation synthesis of indium oxide nanoparticles in water

    International Nuclear Information System (INIS)

    Colloidal solutions of Indium oxide nanoparticles have been produced by means of laser ablation in liquids (LALs) technique by simply irradiating with a second harmonic (532 nm) Nd:YAG laser beam a metallic indium target immersed in distilled water and varying the laser fluence up to 10 J cm-2 and the ablation time up to 120 min. At all the investigated fluences the vaporization process of the indium target is the dominant one. It produces a majority (>80%) of small size (<6 nm) nanoparticles, with a very limited content of larger ones (size between 10 and 20 nm). The amount of particles increases regularly with the ablation time, supporting the scalability of the production technique. The deposited nanoparticles stoichiometry has been verified by both X-ray photoelectron spectroscopy (XPS) and Energy Dispersive X-ray (EDX) analysis. Optical bandgap values of 3.70 eV were determined by UV-vis absorption measurements. All these results confirm the complete oxidation of the ablated material.

  14. Impacts of metal and metal oxide nanoparticles on marine organisms

    International Nuclear Information System (INIS)

    Increasing use of metal and metal oxide nanoparticles [Me(O)NPs] in products means many will inevitably find their way into marine systems. Their likely fate here is sedimentation following hetero-aggregation with natural organic matter and/or free anions, putting benthic, sediment-dwelling and filter feeding organisms most at risk. In marine systems, Me(O)NPs can absorb to micro-organisms with potential for trophic transfer following consumption. Filter feeders, especially bivalves, accumulate Me(O)NPs through trapping them in mucus prior to ingestion. Benthic in-fauna may directly ingest sedimented Me(O)NPs. In fish, uptake is principally via the gut following drinking, whilst Me(O)NPs caught in gill mucus may affect respiratory processes and ion transport. Currently, environmentally-realistic Me(O)NP concentrations are unlikely to cause significant adverse acute health problems, however sub-lethal effects e.g. oxidative stresses have been noted in many organisms, often deriving from dissolution of Ag, Cu or Zn ions, and this could result in chronic health impacts. -- Highlights: • Nanoparticle (NP) use increasing, and NPs ultimately discharged to marine systems. • Metal ion dissolution from NPs causes oxidative stress at relevant concentrations. • Bioaccumulation and trophic transfer of NPs likely at all levels of marine food webs. • Biofilms and filter feeders are major NP accumulators, but many Classes lack study. • Current release levels unlikely to cause chronic damage, but may be a future issue. -- Exposure to metal (oxide) nanoparticles causes sub-lethal effects in marine organisms, the extent of which is related principally to the organisms' feeding regime, habitat and lifestyle

  15. Superparamagnetic iron oxide nanoparticles: magnetic nanoplatforms as drug carriers

    Directory of Open Access Journals (Sweden)

    Wahajuddin

    2012-07-01

    Full Text Available Wahajuddin,1,2 Sumit Arora21Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, 2Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, Rae Bareli, IndiaAbstract: A targeted drug delivery system is the need of the hour. Guiding magnetic iron oxide nanoparticles with the help of an external magnetic field to its target is the principle behind the development of superparamagnetic iron oxide nanoparticles (SPIONs as novel drug delivery vehicles. SPIONs are small synthetic γ-Fe2O3 (maghemite or Fe3O4 (magnetite particles with a core ranging between 10 nm and 100 nm in diameter. These magnetic particles are coated with certain biocompatible polymers, such as dextran or polyethylene glycol, which provide chemical handles for the conjugation of therapeutic agents and also improve their blood distribution profile. The current research on SPIONs is opening up wide horizons for their use as diagnostic agents in magnetic resonance imaging as well as for drug delivery vehicles. Delivery of anticancer drugs by coupling with functionalized SPIONs to their targeted site is one of the most pursued areas of research in the development of cancer treatment strategies. SPIONs have also demonstrated their efficiency as nonviral gene vectors that facilitate the introduction of plasmids into the nucleus at rates multifold those of routinely available standard technologies. SPION-induced hyperthermia has also been utilized for localized killing of cancerous cells. Despite their potential biomedical application, alteration in gene expression profiles, disturbance in iron homeostasis, oxidative stress, and altered cellular responses are some SPION-related toxicological aspects which require due consideration. This review provides a comprehensive understanding of SPIONs with regard to their method of preparation, their utility as drug delivery vehicles, and some concerns which need to

  16. Biogenic terbium oxide nanoparticles as the vanguard against osteosarcoma.

    Science.gov (United States)

    Iram, Sana; Khan, Salman; Ansary, Abu Ayoobul; Arshad, Mohd; Siddiqui, Sahabjada; Ahmad, Ejaz; Khan, Rizwan H; Khan, Mohd Sajid

    2016-11-01

    The synthesis of inner transition metal nanoparticles via an ecofriendly route is quite difficult. This study, for the first time, reports synthesis of terbium oxide nanoparticles using fungus, Fusarium oxysporum. The biocompatible terbium oxide nanoparticles (Tb2O3 NPs) were synthesized by incubating Tb4O7 with the biomass of fungus F. oxysporum. Multiple physical characterization techniques, such as UV-visible and photoluminescence spectroscopy, TEM, SAED, and zeta-potential were used to confirm the synthesis, purity, optical and surface characteristics, crystallinity, size, shape, distribution, and stability of the nanoemulsion of Tb2O3 NPs. The Tb2O3 NPs were found to inhibit the propagation of MG-63 and Saos-2 cell-lines (IC50 value of 0.102μg/mL) and remained non-toxic up to a concentration of 0.373μg/mL toward primary osteoblasts. Cell viability decreased in a concentration-dependent manner upon exposure to 10nm Tb2O3 NPs in the concentration range 0.023-0.373μg/mL. Cell toxicity was evaluated by observing changes in cell morphology, cell viability, oxidative stress parameters, and FACS analysis. Morphological examinations of cells revealed cell shrinkage, nuclear condensation, and formation of apoptotic bodies. The level of ROS within the cells-an indicator of oxidative stress was significantly increased. The induction of apoptosis at concentrations ≤IC50 was corroborated by 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) staining (DNA damage and nuclear fragmentation). Flow-cytometric studies indicated that the response was dose dependent with a threshold effect. PMID:27288964

  17. Supported lipid bilayers as templates to design manganese oxide nanoparticles

    Indian Academy of Sciences (India)

    J Maheshkumar; B Sreedhar; B U Nair; A Dhathathreyan

    2012-09-01

    This work reports on the preparation of nanoclusters of manganese oxide using biotemplating techniques. Supported lipid bilayers (SLBs) on quartz using cationic lipid [Dioctadecyldimethylammonium bromide (DOMA)] and mixed systems with neutral phospholipids dipalmitoyl phosphatidylcholine (DPPC) and dioleoyl phosphatidylcholine (DOPC) have been used as templates to synthesize these nanoparticles in a waterbased medium at room temperature. The Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM) show manganese oxide nanostructures that are composed of crystals or small clusters in the size range of 20-50 nm in diameter. Small angle XRD showed that template removal through calcining process results in nanostructures of the manganese oxide in sizes from 30 to 50 nm. Using these organized assemblies it is possible to control the nano and mesoscopic morphologies of particles and both rod-like and spherical particles can be synthesized.

  18. Shape-dependent bactericidal activity of copper oxide nanoparticle mediated by DNA and membrane damage

    International Nuclear Information System (INIS)

    Highlights: • Spherical and sheet shaped copper oxide nanoparticles were synthesized. • Physical characterizations of these nanoparticles were done by TEM, DLS, XRD, FTIR. • They showed shape dependent antibacterial activity on different bacterial strain. • They induced both membrane damage and ROS mediated DNA damage in bacteria. - Abstract: In this work, we synthesized spherical and sheet shaped copper oxide nanoparticles and their physical characterizations were done by the X-ray diffraction, fourier transform infrared spectroscopy, transmission electron microscopy and dynamic light scattering. The antibacterial activity of these nanoparticles was determined on both gram positive and gram negative bacterial. Spherical shaped copper oxide nanoparticles showed more antibacterial property on gram positive bacteria where as sheet shaped copper oxide nanoparticles are more active on gram negative bacteria. We also demonstrated that copper oxide nanoparticles produced reactive oxygen species in both gram negative and gram positive bacteria. Furthermore, they induced membrane damage as determined by atomic force microscopy and scanning electron microscopy. Thus production of and membrane damage are major mechanisms of the bactericidal activity of these copper oxide nanoparticles. Finally it was concluded that antibacterial activity of nanoparticles depend on physicochemical properties of copper oxide nanoparticles and bacterial strain

  19. The role of stress in self-ordered porous anodic oxide formation and corrosion of aluminum

    Science.gov (United States)

    Capraz, Omer Ozgur

    The phenomenon of plastic flow induced by electrochemical reactions near room temperature is significant in porous anodic oxide (PAO) films, charging of lithium batteries and stress-corrosion cracking (SCC). As this phenomenon is poorly understood, fundamental insight into flow from our work may provide useful information for these problems. In-situ monitoring of the stress state allows direct correlation between stress and the current or potential, thus providing fundamental insight into technologically important deformation and failure mechanisms induced by electrochemical reactions. A phase-shifting curvature interferometry was designed to investigate the stress generation mechanisms on different systems. Resolution of our curvature interferometry was found to be ten times more powerful than that obtained by state-of-art multiple deflectometry technique and the curvature interferometry helps to resolve the conflicting reports in the literature. During this work, formation of surface patterns during both aqueous corrosion of aluminum and formation of PAO films were investigated. Interestingly, for both cases, stress induced plastic flow controls the formation of surface patterns. Pore formation mechanisms during anodizing of the porous aluminum oxide films was investigated . PAO films are formed by the electrochemical oxidation of metals such as aluminum and titanium in a solution where oxide is moderately soluble. They have been used extensively to design numerous devices for optical, catalytic, and biological and energy related applications, due to their vertically aligned-geometry, high-specific surface area and tunable geometry by adjusting process variables. These structures have developed empirically, in the absence of understanding the process mechanism. Previous experimental studies of anodizing-induced stress have extensively focused on the measurement of average stress, however the measurement of stress evolution during anodizing does not provide

  20. Nickel oxide nanoparticles film produced by dead biomass of filamentous fungus

    Science.gov (United States)

    Salvadori, Marcia Regina; Nascimento, Cláudio Augusto Oller; Corrêa, Benedito

    2014-09-01

    The synthesis of nickel oxide nanoparticles in film form using dead biomass of the filamentous fungus Aspergillus aculeatus as reducing agent represents an environmentally friendly nanotechnological innovation. The optimal conditions and the capacity of dead biomass to uptake and produce nanoparticles were evaluated by analyzing the biosorption of nickel by the fungus. The structural characteristics of the film-forming nickel oxide nanoparticles were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). These techniques showed that the nickel oxide nanoparticles had a size of about 5.89 nm and were involved in a protein matrix which probably permitted their organization in film form. The production and uptake of nickel oxide nanoparticles organized in film form by dead fungal biomass bring us closer to sustainable strategies for the biosynthesis of metal oxide nanoparticles.

  1. Structure of Oxide Nanoparticles in Fe-16Cr MA/ODS Ferritic Steel

    Energy Technology Data Exchange (ETDEWEB)

    Hsiung, L; Fluss, M; Kimura, A

    2010-04-06

    Oxide nanoparticles in Fe-16Cr ODS ferritic steel fabricated by mechanical alloying (MA) method have been examined using high-resolution transmission electron microscopy (HRTEM) techniques. A partial crystallization of oxide nanoparticles was frequently observed in as-fabricated ODS steel. The crystal structure of crystalline oxide particles is identified to be mainly Y{sub 4}Al{sub 2}O{sub 9} (YAM) with a monoclinic structure. Large nanoparticles with a diameter larger than 20 nm tend to be incoherent and have a nearly spherical shape, whereas small nanoparticles with a diameter smaller than 10 nm tend to be coherent or semi-coherent and have faceted boundaries. The oxide nanoparticles become fully crystallized after prolonged annealing at 900 C. These results lead us to propose a three-stage formation mechanism of oxide nanoparticles in MA/ODS steels.

  2. Highly Ordered Zinc Oxide Nanotubules Synthesized within the Anodic Aluminum Oxide Template

    Institute of Scientific and Technical Information of China (English)

    WANG Zhen; LI HuLin

    2001-01-01

    @@ Zinc oxide (ZnO) is a wide-band-gap semiconductor, which has a broad range of applications, e.g., in pigment, rubber additives, gas sensors, varistors and transducers1. It has recently been demonstrated that nanophase zinc oxide can be used in photocells of the Gatzel type2, which results in improved current generation efficiency. The properties of high aspect ratios and small sizes of zinc oxide nanotubules or nanowires are expected to improve the luminescence efficiency of the electro-optical devices and the sensitivity of the chemical sensors3.

  3. Highly Ordered Zinc Oxide Nanotubules Synthesized within the Anodic Aluminum Oxide Template

    Institute of Scientific and Technical Information of China (English)

    WANG; Zhen

    2001-01-01

    Zinc oxide (ZnO) is a wide-band-gap semiconductor, which has a broad range of applications, e.g., in pigment, rubber additives, gas sensors, varistors and transducers1. It has recently been demonstrated that nanophase zinc oxide can be used in photocells of the Gatzel type2, which results in improved current generation efficiency. The properties of high aspect ratios and small sizes of zinc oxide nanotubules or nanowires are expected to improve the luminescence efficiency of the electro-optical devices and the sensitivity of the chemical sensors3.  ……

  4. Fundamental aspects of regenerative cerium oxide nanoparticles and their applications in nanobiotechnology

    Science.gov (United States)

    Patil, Swanand D.

    Cerium oxide has been used extensively for various applications over the past two decades. The use of cerium oxide nanoparticles is beneficial in present applications and can open avenues for future applications. The present study utilizes the microemulsion technique to synthesize uniformly distributed cerium oxide nanoparticles. The same technique was also used to synthesize cerium oxide nanoparticles doped with trivalent elements (La and Nd). The fundamental study of cerium oxide nanoparticles identified variations in properties as a function of particle size and also due to doping with trivalent elements (La and Nd). It was found that the lattice parameter of cerium oxide nanoparticles increases with decrease in particle size. Also Raman allowed mode shift to lower energies and the peak at 464 cm-1 becomes broader and asymmetric. The size dependent changes in cerium oxide were correlated to increase in oxygen vacancy concentration in the cerium oxide lattice. The doping of cerium oxide nanoparticles with trivalent elements introduces more oxygen vacancies and expands the cerium oxide lattice further (in addition to the lattice expansion due to the size effect). The lattice expansion is greater for La-doped cerium oxide nanoparticles compared to Nd-doping due to the larger ionic radius of La compared to Nd, the lattice expansion is directly proportional to the dopant concentration. The synthesized cerium oxide nanoparticles were used to develop an electrochemical biosensor of hydrogen peroxide (H2O2). The sensor was useful to detect H2O2 concentrations as low as 1muM in water. Also the preliminary testing of the sensor on tomato stem and leaf extracts indicated that the sensor can be used in practical applications such as plant physiological studies etc. The nanomolar concentrations of cerium oxide nanoparticles were also found to be useful in decreasing ROS (reactive oxygen species) mediated cellular damages in various in vitro cell cultures. Cerium oxide

  5. Adhesion-enhanced thick copper film deposition on aluminum oxide by an ion-beam-mixed Al seed layer

    International Nuclear Information System (INIS)

    We report a highly-adherent 30-μm Cu conductive-path coating on an aluminum-oxide layer anodized on an aluminum-alloy substrate for a metal-printed circuit-board application. A 50-nm Al layer was first coated with an e-beam evaporative deposition method on the anodized oxide, followed by ion bombardment to mix the interfacial region. Subsequently, a Cu coating was deposited onto the mixed seed layer to the designed thickness. Adhesions of the interface were tested by using tape adhesion test, and pull-off tests and showed commercially acceptable adhesions for such thick coating layers. The ion beam mixing (IBM) plays the role of fastening the thin seed coating layer to the substrate and enhancing the adhesion of the Cu conductive path on the anodized aluminum surface.

  6. Green Approach for Fabrication and Applications of Zinc Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Brajesh Kumar

    2014-01-01

    Full Text Available Zinc oxide nanoparticles (ZnO-NPs are known to be one of the multifunctional inorganic compounds which are widely used in everyday applications. This study aims to fabricate ZnO-NPs using grapefruit (Citrus paradisi peel extract with particle size ranging from 12 to 72 nm. Structural, morphological, and optical properties of the synthesized nanoparticles have been characterized by using UV-Vis spectrophotometer, TEM, DLS, and FTIR analysis. They show the significant photocatalytic degradation efficiency (>56%, 10 mg/L, 6 h against methylene blue and antioxidant efficacy (≥80% for 1.2 mM against 1,1-diphenyl-2-picrylhydrazyl. From the results obtained it is suggested that green ZnO-NPs could be used effectively in environmental safety applications and also can address future medical concerns.

  7. A green synthesis of copper oxide nanoparticles by mechanochemical method

    Directory of Open Access Journals (Sweden)

    Azadeh Tadjarodi

    2014-10-01

    Full Text Available Copper oxide nanoparticles were successfully synthesized by mechanochemical reaction, which is a green, low cost, solvent free, rapid method and followed by calcining treatment. Copper acetate monohydrate and urea were used as reagents and the resulted precursor was calcined at 500 C for 2h in air. The scanning electron microscopy (SEM revealed the formation of nanoparticles with an average size of about 86 nm. The Fourier transform infrared (FT–IR spectrum and X-ray powder diffraction (XRD pattern of the product confirmed all of reflections can be indexed to pure phase of CuO with a monoclinic crystal system. The diffuse reflectance spectrum (DRS showed a band gap of 1.7 eV.

  8. Green Approach for Fabrication and Applications of Zinc Oxide Nanoparticles

    Science.gov (United States)

    Smita, Kumari; Cumbal, Luis

    2014-01-01

    Zinc oxide nanoparticles (ZnO-NPs) are known to be one of the multifunctional inorganic compounds which are widely used in everyday applications. This study aims to fabricate ZnO-NPs using grapefruit (Citrus paradisi) peel extract with particle size ranging from 12 to 72 nm. Structural, morphological, and optical properties of the synthesized nanoparticles have been characterized by using UV-Vis spectrophotometer, TEM, DLS, and FTIR analysis. They show the significant photocatalytic degradation efficiency (>56%, 10 mg/L, 6 h) against methylene blue and antioxidant efficacy (≥80% for 1.2 mM) against 1,1-diphenyl-2-picrylhydrazyl. From the results obtained it is suggested that green ZnO-NPs could be used effectively in environmental safety applications and also can address future medical concerns. PMID:25374484

  9. Safety assessment of silica and zinc oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    An SSA

    2014-12-01

    Full Text Available Seong Soo A An,1 Meyoung-Kon Kim2 1Department of Bionanotechnology, Gachon Medical Research Institute, Gachon University, Seongnam, Gyeonggi, Korea; 2Department of Biochemistry and Molecular Biology, Korea University Medical School and College, Seoul, KoreaThe current volume is a special issue focusing on a safety assessment of nanoparticles, from their physicochemical properties to government regulations. It features twenty-five papers, discussing general issues with the possible harmfulness of two different types of nanoparticles (NPs; silica (SiO2 and zinc oxide (ZnO. Six papers describe detailed analyses from 90-day repeated administrations of NPs, and finally there is a series of technical reports, formatted by the National Toxicology Program (NTP, dealing with safety issues regarding international cooperation with the OECD (Organisation for Economic Co-operation and Development Working Party on Manufactured Nanomaterials (WPMN.

  10. Vacancy-Mediated Magnetism in Pure Copper Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Gao Daqiang

    2010-01-01

    Full Text Available Abstract Room temperature ferromagnetism (RTF is observed in pure copper oxide (CuO nanoparticles which were prepared by precipitation method with the post-annealing in air without any ferromagnetic dopant. X-ray photoelectron spectroscopy (XPS result indicates that the mixture valence states of Cu1+ and Cu2+ ions exist at the surface of the particles. Vacuum annealing enhances the ferromagnetism (FM of CuO nanoparticles, while oxygen atmosphere annealing reduces it. The origin of FM is suggested to the oxygen vacancies at the surface/or interface of the particles. Such a ferromagnet without the presence of any transition metal could be a very good option for a class of spintronics.

  11. Doping optimization and surface modification of aluminum doped zinc oxide films as transparent conductive coating

    International Nuclear Information System (INIS)

    Aluminum doped zinc oxide (ZnO:Al) films were grown using spray pyrolysis technique. Effect of doping on structural, electrical, optical and morphological properties was studied. Aluminum doping improved the prominence of [002] growth while maintaining the grain size ∼ 48 nm. Using an intermediate Al/Zn atomic ratio in precursor (1.5:100), we could achieve a low resistivity ρ ∼ 7 × 10−4 Ωcm. These films possessed an average visible transmittance ∼ 88%, an optical gap ∼ 3.7 eV and plasma wavelength at 1.87 μm. A simultaneous use of methanol and iso-propanol in the precursor lead to a moderate surface roughness ∼ 12 nm. The films were surface modified using wet chemical etching in diluted hydrochloric acid, for varied time intervals (5 s–15 s) and etchant concentrations (0.125%–1%). The etching experiments could be used to know the building of the film as also to modify the surface for desired optical and morphological properties. - Highlights: ► High conductivity ZnO:Al films prepared by spray pyrolysis. ► Physical properties very competitive as transparent conductor. ► Co-use of methanol and iso-propanol made smoother but compact films. ► Wet chemical etching helped to modify the surface and understand the growth.

  12. Aluminum work function: Effect of oxidation, mechanical scraping and ion bombardment

    Science.gov (United States)

    Vinet, P.; Lemogne, T.; Montes, H.

    1985-01-01

    Surface studies have been performed on aluminum polycrystalline surfaces which have been mechanically scraped. Such studies were initiated in order to understand surface effects occurring in tribological processes which involve rubbing surfaces and the effects of adsorption of oxygen. To characterize the surfaces, the following three different experimental approaches have been used: (1) X.P.S. (X-ray photoelectron spectroscopy), in order to check the cleanliness of the surfaces and follow the adsorption and oxidation kinetics; (2) Analysis of the work function changes by following the energy spectra of secondary electrons emitted under low energy electron bombardment; and (3) Analysis of photoemission intensities under U.V. excitation. The reference state being chosen to be the surface cleaned by ion bombardment and exposures to oxygen atmospheres have been shown to lower the work function of clean polycrystalline aluminum by 1.2 eV. The oxygen pressure is found to affect only the kinetics of these experiments. Mechanical scraping has been shown to induce a decrease ( 0.3 eV) in the work function, which could sharply modify the kinetics of adsorption on the surface.

  13. Formation of unidirectional nanoporous structures in thickly anodized aluminum oxide layer

    Institute of Scientific and Technical Information of China (English)

    Hyun-Chae NA; Taek-Jin SUNG; Seok-Heon YOON; Seung-Kyoun HYUN; Mok-Soon KIM; Young-Gi LEE; Sang-Hyun SHIN; Seok-Moon CHOI; Sung YI

    2009-01-01

    A series of anodic aluminum oxide(AAO) was grown on the commercially pure 1050 aluminum sheet by controlling electrolyte temperature (2-15 ℃) and anodizing time (0.5-6 h), using a fixed applied current density of 3 A/dm2 in diluted sulfuric acid electrolyte. A crack-free thick AAO with the thickness of 105-120 ìm and containing unidirectional nano sized pores (average pore diameter of 5-7 nm) is successfully achieved in the specimens anodized for 2 h, irrespective of electrolyte temperature. When anodizing time reaches 6 h, very thick AAO with the thickness of 230-284 ìm is grown, and average diameter of unidirectional pores is in the range of 6-24 nm. The higher values in both the AAO thickness and pore diameter are attained for the specimens anodized at higher temperatures of 10-15 ℃. A crack is observed to exist in the AAO after anodizing up to 4 h and more. A higher fraction (more than 9%) of the crack is shown in the specimens anodized at higher temperatures of 10-15 ℃ for 6 h and a considerable amount of giant cracks are contained.

  14. Effects of Complex Structured Anodic Oxide Dielectric Layer Grown in Pore Matrix for Aluminum Capacitor.

    Science.gov (United States)

    Shin, Jin-Ha; Yun, Sook Young; Lee, Chang Hyoung; Park, Hwa-Sun; Suh, Su-Jeong

    2015-11-01

    Anodization of aluminum is generally divided up into two types of anodic aluminum oxide structures depending on electrolyte type. In this study, an anodization process was carried out in two steps to obtain high dielectric strength and break down voltage. In the first step, evaporated high purity Al on Si wafer was anodized in oxalic acidic aqueous solution at various times at a constant temperature of 5 degrees C. In the second step, citric acidic aqueous solution was used to obtain a thickly grown sub-barrier layer. During the second anodization process, the anodizing potential of various ranges was applied at room temperature. An increased thickness of the sub-barrier layer in the porous matrix was obtained according to the increment of the applied anodizing potential. The microstructures and the growth of the sub-barrier layer were then observed with an increasing anodizing potential of 40 to 300 V by using a scanning electron microscope (SEM). An impedance analyzer was used to observe the change of electrical properties, including the capacitance, dissipation factor, impedance, and equivalent series resistance (ESR) depending on the thickness increase of the sub-barrier layer. In addition, the breakdown voltage was measured. The results revealed that dielectric strength was improved with the increase of sub-barrier layer thickness. PMID:26726615

  15. In-Line Sputtered Gallium and Aluminum Codoped Zinc Oxide Films for Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Shang-Chou Chang

    2014-01-01

    Full Text Available Gallium and aluminum codoped zinc oxide (GAZO films were deposited at different temperatures by in-line sputtering. Aluminum is thermally unstable compared to other elements in GAZO films. The grains of GAZO films increase with deposition temperature. Coalescence between grains was observed for GAZO films deposited at 250°C. The deposition temperature exhibits positive influence on crystallinity, and electrical and optical properties of GAZO films. The carrier concentration and mobility of GAZO films increase, while the electrical resistivity of GAZO films decreases with deposition temperature. The average optical transmittance of GAZO films rises with deposition temperature. In-line sputtering demonstrates a potential method with simplicity, mass production, and large-area deposition to produce GAZO films with good electrical and optical quality. The electrical resistivity of 4.3 × 10−4 Ω cm and the average optical transmittance in the visible range from 400 to 800 nm of 92% can be obtained for GAZO films deposited at 250°C. The hybrid organic solar cells (OSC were fabricated on GAZO-coated glass substrates. Blended poly(3-hexylthiophene (P3HT and [6,6]-phenyl C61 butyric acid methyl ester (PCBM were the photoactive materials in OSC. The power conversion efficiency of OSC is 0.65% for the OSC with the 250°C deposited GAZO electrode.

  16. Effects of Cerium Oxide Nanoparticles on Sorghum Plant Traits

    Science.gov (United States)

    Mu, L.; Chen, Y.; Darnault, C. J. G.; Rauh, B.; Kresovich, S.; Korte, C.

    2015-12-01

    Nanotechnology and nanomaterials are considered as the development of the modern science. However, besides with that wide application, nanoparticles arouse to the side effects on the environment and human health. As the catalyst of ceramics and fuel industry, Cerium (IV) oxide nanoparticles (CeO2 NPs) can be found in the environment following their use and life-cycle. Therefore, it is critical to assess the potential effects that CeO2 NPs found in soils may have on plants. In this study, CeO2 NPs were analyzed for the potential influence on the sorghum [Sorghum bicolor (L.) Moench] (Reg. no. 126) (PI 154844) growth and traits. The objectives of this research were to determine whether CeO2 NPs impact the sorghum germination and growth characteristics. The sorghum was grown in the greenhouse located at Biosystems Research Complex, Clemson University under different CeO2 NPs treatments (0mg; 100mg; 500mg; 1000mg CeO2 NPs/Kg soil) and harvested around each month. At the end of the each growing period, above ground vegetative tissue was air-dried, ground to 2mm particle size and compositional traits estimated using near-infrared spectroscopy. Also, the NPK value of the sorghum tissue was tested by Clemson Agriculture Center. After the first harvest, the result showed that the height of above ground biomass under the nanoparticles stress was higher than that of control group. This difference between the control and the nanoparticles treatments was significant (F>F0.05; LSD). Our results also indicated that some of the compositional traits were impacted by the different treatments, including the presence and/or concentrations of the nanoparticles.

  17. Radiopacity and cytotoxicity of Portland cement associated with niobium oxide micro and nanoparticles

    Directory of Open Access Journals (Sweden)

    Leticia Boldrin MESTIERI

    2014-12-01

    Full Text Available Objective Mineral Trioxide Aggregate (MTA is composed of Portland Cement (PC and bismuth oxide (BO. Replacing BO for niobium oxide (NbO microparticles (Nbµ or nanoparticles (Nbη may improve radiopacity and bioactivity. The aim of this study was to evaluate the radiopacity and cytotoxicity of the materials: 1 PC; 2 White MTA; 3 PC+30% Nbµ; 4 PC+30% Nbη. Material and Methods For the radiopacity test, specimens of the different materials were radiographed along an aluminum step-wedge. For cell culture assays, Saos-2 osteoblastic-cells (ATCC HTB-85 were used. Cell viability was evaluated through MTT assay, and bioactivity was assessed by alkaline phosphatase activity assay. Results The results demonstrated higher radiopacity for MTA, followed by Nbµ and Nbη, which had similar values. Cell culture analysis showed that PC and PC+NbO associations promoted greater cell viability than MTA. Conclusions It was concluded that the combination of PC+NbO is a potential alternative for composition of MTA.

  18. Dispersion of silicon carbide nanoparticles in a AA2024 aluminum alloy by a high-energy ball mill

    Energy Technology Data Exchange (ETDEWEB)

    Carreño-Gallardo, C.; Estrada-Guel, I. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología-Chihuahua, Miguel de Cervantes No. 120, CP 31109, Chihuahua, México (Mexico); López-Meléndez, C. [Universidad La Salle Chihuahua, Prol. Lomas de Majalca No. 11201, CP 31020, Chihuahua, México (Mexico); Martínez-Sánchez, R., E-mail: roberto.martinez@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología-Chihuahua, Miguel de Cervantes No. 120, CP 31109, Chihuahua, México (Mexico)

    2014-02-15

    Highlights: • Synthesis of 2024-SiC{sub NP} nanocomposite by mechanical milling process. • SiC nanoparticles improved mechanical properties of aluminum alloy 2024 matrix. • A homogeneous distribution of SiC nanoparticles were observed in the matrix • Compressive and hardness properties of the composite are improved significantly. -- Abstract: Al{sub 2024} alloy was reinforced with silicon carbide nanoparticles (SiC{sub NP}), whose concentration was varied in the range from 0 to 5 wt.%; some composites were synthesized with the mechanical milling (MM) process. Structure and microstructure of the consolidated samples were studied by X-ray diffraction and transmission electron microscopy, while mechanical properties were investigated by compressive tests and hardness measurements. The microstructural evidence shows that SiC{sub NP} were homogeneously dispersed into the Al{sub 2024} alloy using high-energy MM after 2 h of processing. On the other hand, an increase of the mechanical properties (yield stress, maximum strength and hardness) was observed in the synthesized composites as a direct function of the SiC{sub NP} content. In this research several strengthening mechanisms were observed, but the main was the obstruction of dislocations movement by the addition of SiC{sub NP}.

  19. Dispersion of silicon carbide nanoparticles in a AA2024 aluminum alloy by a high-energy ball mill

    International Nuclear Information System (INIS)

    Highlights: • Synthesis of 2024-SiCNP nanocomposite by mechanical milling process. • SiC nanoparticles improved mechanical properties of aluminum alloy 2024 matrix. • A homogeneous distribution of SiC nanoparticles were observed in the matrix • Compressive and hardness properties of the composite are improved significantly. -- Abstract: Al2024 alloy was reinforced with silicon carbide nanoparticles (SiCNP), whose concentration was varied in the range from 0 to 5 wt.%; some composites were synthesized with the mechanical milling (MM) process. Structure and microstructure of the consolidated samples were studied by X-ray diffraction and transmission electron microscopy, while mechanical properties were investigated by compressive tests and hardness measurements. The microstructural evidence shows that SiCNP were homogeneously dispersed into the Al2024 alloy using high-energy MM after 2 h of processing. On the other hand, an increase of the mechanical properties (yield stress, maximum strength and hardness) was observed in the synthesized composites as a direct function of the SiCNP content. In this research several strengthening mechanisms were observed, but the main was the obstruction of dislocations movement by the addition of SiCNP

  20. Comparison of antibacterial activities of cadmium oxide nanoparticles against Pseudomonas Aeruginosa and Staphylococcus Aureus bacteria

    Directory of Open Access Journals (Sweden)

    Bahareh Salehi

    2015-01-01

    Conclusion: This study showed that antibacterial effects of cadmium oxide nanoparticles on positive gram bacteria are stronger than negative gram bacteria and antibacterial effects of cdo nanoparticles against both bacteria, but Staphylococcus aureus bacteria were more sensitive to nanoparticles as compared to Pseudomonas aeruginosa.

  1. Study on the mechanism of antibacterial action of magnesium oxide nanoparticles against foodborne pathogens

    Science.gov (United States)

    Magnesium oxide nanoparticles (MgO nanoparticles, with average size of 20 nm) have strong antibacterial activities against several important foodborne pathogens. Resazurin (a redox sensitive dye) microplate assay was used for measuring growth inhibition of bacteria treated with MgO nanoparticles. Th...

  2. Copper-aluminum oxide catalysts for total oxidation of toluene synthesized by thermal decomposition of co-precipitated precursors

    International Nuclear Information System (INIS)

    Highlights: • Cu–Al oxides obtained by coprecipitation are active catalysts in toluene combustion. • Advantage of the catalyst is low copper content and alkali-free precipitating agent. • The stable oxide form built of CuO and CuAl2O4 is attained at 900 °C. • The optimum atomic Cu:Al ratio, ensuring maximum toluene conversion, is about 0.6. • The most active sample contains small CuO crystallites dispersed on the surface. - Abstract: Copper–aluminum containing precursors with various Cu/Al molar ratios (from 0.32–1.28) were prepared by co-precipitation in the presence of ammonium carbonate. The thermal stability of the obtained materials was investigated by thermal analysis, which revealed three crucial decomposition steps, finally resulting in the formation of mixed Cu–Al oxides. The changes in structure and texture of the samples at each decomposition step were examined by X-ray diffraction (XRD), diffuse reflectance UV–vis spectroscopy (UV–vis-DRS) and low temperature sorption of nitrogen. It was found that the entire removal of structural carbonates requires a calcination temperature as high as 900 °C. The samples after thermal treatment at this temperature varied in the phase composition of the bulk (determined by XRD) as well as of the surface (determined by X-ray photoelectron spectroscopy). All samples contained the CuAl2O4 phase. Furthermore, an increase in Cu content led to the appearance of an increasing amount of CuO. Copper oxide in the form of relatively small crystallites turned out to be the catalytically active phase in the total oxidation of toluene

  3. Copper-aluminum oxide catalysts for total oxidation of toluene synthesized by thermal decomposition of co-precipitated precursors

    Energy Technology Data Exchange (ETDEWEB)

    Białas, Anna [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków (Poland); Kuśtrowski, Piotr, E-mail: kustrows@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków (Poland); Dudek, Barbara; Piwowarska, Zofia; Wach, Anna [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków (Poland); Michalik, Marek [Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków (Poland); Kozak, Marek [Division of Petroleum Processing, Oil and Gas Institute, Łukasiewicza 1, 31-429 Kraków (Poland)

    2014-08-20

    Highlights: • Cu–Al oxides obtained by coprecipitation are active catalysts in toluene combustion. • Advantage of the catalyst is low copper content and alkali-free precipitating agent. • The stable oxide form built of CuO and CuAl{sub 2}O{sub 4} is attained at 900 °C. • The optimum atomic Cu:Al ratio, ensuring maximum toluene conversion, is about 0.6. • The most active sample contains small CuO crystallites dispersed on the surface. - Abstract: Copper–aluminum containing precursors with various Cu/Al molar ratios (from 0.32–1.28) were prepared by co-precipitation in the presence of ammonium carbonate. The thermal stability of the obtained materials was investigated by thermal analysis, which revealed three crucial decomposition steps, finally resulting in the formation of mixed Cu–Al oxides. The changes in structure and texture of the samples at each decomposition step were examined by X-ray diffraction (XRD), diffuse reflectance UV–vis spectroscopy (UV–vis-DRS) and low temperature sorption of nitrogen. It was found that the entire removal of structural carbonates requires a calcination temperature as high as 900 °C. The samples after thermal treatment at this temperature varied in the phase composition of the bulk (determined by XRD) as well as of the surface (determined by X-ray photoelectron spectroscopy). All samples contained the CuAl{sub 2}O{sub 4} phase. Furthermore, an increase in Cu content led to the appearance of an increasing amount of CuO. Copper oxide in the form of relatively small crystallites turned out to be the catalytically active phase in the total oxidation of toluene.

  4. Synthesis and properties of iridescent Zn-containing anodic aluminum oxide films

    International Nuclear Information System (INIS)

    A simple method of fabricating Zn-containing anodic aluminum oxide films for multifunctional anticounterfeit technology is reported. The resulting membranes were characterized with UV–vis illumination studies, natural light illumination color experiments, and electron microscopy analysis. Deposition of Zn in the nanopore region can enhance the color saturation of the thin alumina film with different colors dramatically. Both the anodization time and etching time have great influence on the structural color. The mechanisms for the emergence of this phenomenon are discussed and theoretical analysis further demonstrates the experimental results. - Highlights: • Iridescent PAA@Zn nanocomposite films were successfully fabricated. • A simple organics-assisted method is applied to making a series of fancy and multicolor patterns. • The color varies with the angle of incidence of the light used to view the film as is expected with Bragg–Snell formula. • Such colored films could be used in multifunctional anti-counterfeiting applications

  5. Photoluminescence and Raman studies in swift heavy ion irradiated polycrystalline aluminum oxide

    Indian Academy of Sciences (India)

    K R Nagabhushana; B N Lakshminarasappa; Fouran Singh

    2009-10-01

    Polycrystalline aluminum oxide is synthesized by combustion technique and XRD studies of the sample revealed the -phase. The synthesized sample is irradiated with 120 MeV swift Au9+ ions for the fluence in the range from 1 × 1011 to 1 × 1013 ions cm-2. A broad photoluminescence (PL) emission with peak at ∼447 nm and two sharp emissions with peak at ∼ 679 and ∼ 695 nm are observed in pristine when sample was excited with 326 nm. However, in the irradiated samples the PL intensity at ∼ 447, 679 and 695 nm decreases with increase in ion fluence. The -Al2O3 gives rise to seven Raman modes with Raman intensity with peaks at ∼ 253, 396, 417, 546, 630, 842, 867 cm-1 observed in pristine. The intensity of these modes decreases with increase in ion fluence. However, the Raman modes observed at lower fluences are found to disappear at higher fluence.

  6. Effect of intermetallic phases on the anodic oxidation and corrosion of 5A06 aluminum alloy

    Science.gov (United States)

    Li, Song-mei; Li, Ying-dong; Zhang, You; Liu, Jian-hua; Yu, Mei

    2015-02-01

    Intermetallic phases were found to influence the anodic oxidation and corrosion behavior of 5A06 aluminum alloy. Scattered intermetallic particles were examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) after pretreatment. The anodic film was investigated by transmission electron microscopy (TEM), and its corrosion resistance was analyzed by electrochemical impedance spectroscopy (EIS) and Tafel polarization in NaCl solution. The results show that the size of Al-Fe-Mg-Mn particles gradually decreases with the iron content. During anodizing, these intermetallic particles are gradually dissolved, leading to the complex porosity in the anodic film beneath the particles. After anodizing, the residual particles are mainly silicon-containing phases, which are embedded in the anodic film. Electrochemical measurements indicate that the porous anodic film layer is easily penetrated, and the barrier plays a dominant role in the overall protection. Meanwhile, self-healing behavior is observed during the long immersion time.

  7. Tribological Influence of Kinematic Oil Viscosity Impregnated in Nano pores of Anodic Aluminum Oxide Film

    International Nuclear Information System (INIS)

    The friction behavior of a 60-μm-thick anodic aluminum oxide (AEU) film having cylindrical nano pores of 45-nm diameter was investigated as a function of impregnated oil viscosity ranging from 3.4 to 392.6 CT. Reciprocating ball-on-flat sliding friction tests using a 1-mm-diameter steel ball as the counterpart were carried out with normal load ranging from 0.1 to 1 N in an ambient environment. The friction coefficient significantly decreased with an increase in the oil viscosity. The boundary lubrication film remained effectively under all test conditions when high-viscosity oil was impregnated, whereas it was easily destroyed when low-viscosity oil was impregnated. Thin plastic deformed layer patches were formed on the worn surface with high-viscosity oil without evidence of thromboembolic reaction and transfer of counterpart material

  8. Nanoporous anodized aluminum oxide-coated polycarbonate surface: Tailoring of transmittance and reflection properties

    International Nuclear Information System (INIS)

    Nanostructured coatings increase the transmittance and decrease the reflection of polycarbonate (PC). In this work, nanoporous anodized aluminum oxide (AAO) coating was formed electrochemically on a PC surface. The reflection properties of the AAO-coated PC were modified by varying the thickness of the AAO layer, the anodization parameters, and the pore size of AAO. Transmittance and reflection were measured by ellipsometry. The optical transmittance of the AAO film on PC was 86-94% in the wavelength range 420-780 nm, which was about four percentage units higher than the transmittance of uncoated PC. The minimum reflection of 0.2% was observed for PC with an AAO coating of 177 nm. The reflection was about five percentage units less than the corresponding value for uncoated polycarbonate. Nanoporous surfaces and profiles of AAO were characterized by Scanning Electron Microscope

  9. Screen Cage Ion Plating (SCIP) and scratch testing of polycrystalline aluminum oxide

    Science.gov (United States)

    Spalvins, Talivaldis; Sliney, Harold E.; Deadmore, Daniel L.

    1992-01-01

    A screen cage ion plating (SCIP) technique was developed to apply silver films on electrically nonconducting aluminum oxide. It is shown that SCIP has remarkable throwing power; surfaces to be coated need not be in direct line of sight with the evaporation source. Scratch tests, employing a diamond stylus with a 200 micro m radius tip, were performed on uncoated and on silver coated alumina. Subsequent surface analysis show that a significant amount of silver remains on the scratched surfaces, even in areas where high stylus load produced severe crack patterns in the ceramic. Friction coefficients were lowered during the scratch tests on the coated alumina indicating that this modification of the ion planting process should be useful for applying lubricating films of soft metals to electrical insulating materials. The very good throwing power of SCIP also strongly suggests general applicability of this process in other areas of technology, e.g., electronics, in addition to tribology.

  10. Studies of aluminum oxide thin films deposited by laser ablation technique

    Science.gov (United States)

    Płóciennik, P.; Guichaoua, D.; Korcala, A.; Zawadzka, A.

    2016-06-01

    This paper presents the structural and optical investigations of the aluminum oxide nanocrystalline thin films. Investigated films were fabricated by laser ablation technique in high vacuum onto quartz substrates. The films were deposited at two different temperatures of the substrates equal to room temperature and 900 K. X-ray Diffraction spectra proved nanocrystalline character and the corundum phase of the film regardless on the substrate temperature during the deposition process. Values of the refractive indices, extinction and absorption coefficients were calculated by using Transmission and Reflection Spectroscopy in the UV-VIS-NIR range of the wavelength. Coupling Prism Method was used for films thickness estimations. Experimental measurements and theoretical calculations of the Third Harmonic Generation were also reported. Obtained results show that the lattice strain may affect obtained values of the third order nonlinear optical susceptibility.

  11. Nanoporous anodized aluminum oxide-coated polycarbonate surface: Tailoring of transmittance and reflection properties

    Energy Technology Data Exchange (ETDEWEB)

    Saarikoski, Inka; Suvanto, Mika [Department of Chemistry, University of Joensuu, P.O. Box 111, FI-80101 Joensuu (Finland); Pakkanen, Tapani A. [Department of Chemistry, University of Joensuu, P.O. Box 111, FI-80101 Joensuu (Finland)], E-mail: Tapani.Pakkanen@joensuu.fi

    2008-10-01

    Nanostructured coatings increase the transmittance and decrease the reflection of polycarbonate (PC). In this work, nanoporous anodized aluminum oxide (AAO) coating was formed electrochemically on a PC surface. The reflection properties of the AAO-coated PC were modified by varying the thickness of the AAO layer, the anodization parameters, and the pore size of AAO. Transmittance and reflection were measured by ellipsometry. The optical transmittance of the AAO film on PC was 86-94% in the wavelength range 420-780 nm, which was about four percentage units higher than the transmittance of uncoated PC. The minimum reflection of 0.2% was observed for PC with an AAO coating of 177 nm. The reflection was about five percentage units less than the corresponding value for uncoated polycarbonate. Nanoporous surfaces and profiles of AAO were characterized by Scanning Electron Microscope.

  12. Graphene-Assisted Chemical Etching of Silicon Using Anodic Aluminum Oxides as Patterning Templates.

    Science.gov (United States)

    Kim, Jungkil; Lee, Dae Hun; Kim, Ju Hwan; Choi, Suk-Ho

    2015-11-01

    We first report graphene-assisted chemical etching (GaCE) of silicon by using patterned graphene as an etching catalyst. Chemical-vapor-deposition-grown graphene transferred on a silicon substrate is patterned to a mesh with nanohole arrays by oxygen plasma etching using an anodic- aluminum-oxide etching mask. The prepared graphene mesh/silicon is immersed in a mixture solution of hydrofluoric acid and hydro peroxide with various molecular fractions at optimized temperatures. The silicon underneath graphene mesh is then selectively etched to form aligned nanopillar arrays. The morphology of the nanostructured silicon can be controlled to be smooth or porous depending on the etching conditions. The experimental results are systematically discussed based on possible mechanisms for GaCE of Si. PMID:26473800

  13. Microstructures and Composition of Ceramic Coatings on Aluminum Produced by Micro-Arc Oxidation

    Institute of Scientific and Technical Information of China (English)

    SHEN De-jiu; WANG Yu-lin; GU Wei-chao; XING Guang-zhong

    2004-01-01

    Microstructures and phase composition of the ceramic coatings formed on pure aluminum by heteropolar pulsed current ceramic synthesizing system for different periods were investigated by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). Results show that the amount of the discharge channels in the ceramic coating sminish while the aperture largen in the micro-arc oxidation process, and the surface of the ceramic coatingmelted and solidified in the process.XRD studies of ceramic coatings deposited for different time show that these coatings consist mainly of α-Al2 O3, γ-Al2 O3 , θ-Al2 O3 and a little amorphous phase, and phase composition of compact and porous ceramic coatings don' t have much difference but have a little change of the content of α-Al2 O3 and amorphous phase.

  14. Synthesis of ordered Sinanowire arrays in porous anodic aluminum oxide templates

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Highly ordered polycrystalline Si nanowire arrays were synthesized in porous anodic aluminum oxide (AAO) templates by the chemical vapor deposition (CVD)method. The morphological structure, the crystal character of Si nanowire arrays and the individual nanowire were analyzed by the transmission electron microscopy (TEM),scanning electron microscopy (SEM), atom force microscopy (AFM) and the X-ray diffraction spectrum (XRD), respectively. It is shown that most fabricated silicon nanowires (SiNWs) tend to be assembled parallelly in bundles and constructed with highly orientated arrays. This method provides a simple and low cost fabricating craftwork and the diameters and lengths of SiNWs can be controlled, the large area Si nanowire arrays can be achieved easily under such a way.The curling and twisting SiNWs are fewer than those by other synthesis methods.

  15. Quench of molten aluminum oxide associated with in-vessel debris retention by RPV internal water

    International Nuclear Information System (INIS)

    In-vessel debris coolability experiments were performed in ALPHA program at JAERI. Molten aluminum oxide (Al2O3) was poured into a pool of water in a lower head experimental vessel. Post-test observation and measurement using an ultrasonic technique indicated the formation of the interfacial gap between the solidified Al2O3 and the vessel wall. Thermal responses of the vessel wall implied that the interfacial gap acted initially as a thermal resistance and water subsequently penetrated into the interfacial gap. The maximum heat flux at the inner surface of the vessel facing to the solidified Al2O3 was roughly evaluated to be ranged from 320 kW/m2 to 600 kW/m2. A post-test analysis was conducted with CAMP code. The influence of the interfacial gap on thermal behavior of Al2O3 and the vessel wall was examined. (authors)

  16. Hydrogenation of Levulinic Acid over Nickel Catalysts Supported on Aluminum Oxide to Prepare γ-Valerolactone

    Directory of Open Access Journals (Sweden)

    Jie Fu

    2015-12-01

    Full Text Available Four types of nickel catalysts supported on aluminum oxide (Ni/Al2O3 with different nickel loadings were synthesized using the co-precipitation method and were used for the hydrogenation of levulinic acid (LA to prepare γ-valerolactone (GVL. The synthesized Ni/Al2O3 catalysts exhibited excellent catalytic activity in dioxane, and the activity of the catalysts was excellent even after being used four times in dioxane. The catalytic activity in dioxane as a solvent was found to be superior to the activity in water. Nitrogen physisorption, X-ray diffraction, and transmission electron microscopy were employed to characterize the fresh and used catalysts. The effects of the nickel loading, temperature, hydrogen pressure, and substrate/catalyst ratio on the catalytic activity were investigated.

  17. Characterization of Anodic Aluminum Oxide Membrane with Variation of Crystallizing Temperature for pH Sensor.

    Science.gov (United States)

    Yeo, Jin-Ho; Lee, Sung-Gap; Jo, Ye-Won; Jung, Hye-Rin

    2015-11-01

    We fabricated electrolyte-dielectric-metal (EDM) device incorporating a high-k Al2O3 sensing membrane from a porous anodic aluminum oxide (AAO) using a two step anodizing process for pH sensors. In order to change the properties of the AAO template, the crystallizing temperature was varied from 400 degrees C to 700 degrees C over 2 hours. The structural properties were observed by field emission scanning electron microscopy (FE-SEM). The pH sensitivity increased with an increase in the crystallizing temperature from 400 degrees C to 600 degrees C. However at 700 degrees C, deformation occurred. The porous AAO sensor with a crystallizing temperature of 600 degrees C displayed the good sensitivity and long-term stability and the values were 55.7 mV/pH and 0.16 mV/h, respectively. PMID:26726567

  18. Preparation of Graphene Oxide Stabilized Nickel Nanoparticles with Thermal Effusivity Properties by Laser Ablation Method

    Directory of Open Access Journals (Sweden)

    Amir Reza Sadrolhosseini

    2013-01-01

    Full Text Available Nickel nanoparticles were dispersed uniformly in a graphene oxide solution, using a laser ablation technique with different ablation times that ranged from 5 to 20 minutes. The results indicate that the nickel nanoparticle sizes inside the graphene oxide decreased, and the volume fraction for the nickel nanoparticles in the graphene oxide increased with an increasing ablation time. Further, using Fourier Transform Infrared Spectroscopy, the nickel nanoparticles in the graphene oxide demonstrate greater stability from possible agglomeration when the nanoparticle was capped with oxygen from the carboxyl group of the graphene oxide. The thermal effusivity of the graphene oxide and nickel nanoparticle graphene oxide composite was measured using a photoacoustic technique. The concentration of graphene oxide shifted from 0.05 mg/L to 2 mg/L, and the thermal effusivity increased from 0.153 W·s1/2·cm−2·K−1 to 0.326 W·s1/2·cm−2·K−1. In addition, the thermal effusivity of the nickel nanoparticles graphene oxide composite increased with an increase in the volume fraction of nickel nanoparticles from 0.1612 W·s1/2·cm−2·K−1 to 0.228 W·s1/2·cm−2·K−1.

  19. The interfacial orientation relationship of oxide nanoparticles in a hafnium-containing oxide dispersion-strengthened austenitic stainless steel

    International Nuclear Information System (INIS)

    This work reports comprehensive investigations on the orientation relationship of the oxide nanoparticles in a hafnium-containing austenitic oxide dispersion-strengthened 316 stainless steel. The phases of the oxide nanoparticles were determined by a combination of scanning transmission electron microscopy–electron dispersive X-ray spectroscopy, atom probe tomography and synchrotron X-ray diffraction to be complex Y–Ti–Hf–O compounds with similar crystal structures, including bixbyite Y2O3, fluorite Y2O3–HfO2 solid solution and pyrochlore (or fluorite) Y2(Ti,Hf)2−xO7−x. High resolution transmission electron microscopy was used to characterize the particle–matrix interfaces. Two different coherency relationships along with one axis-parallel relation between the oxide nanoparticles and the steel matrix were found. The size of the nanoparticles significantly influences the orientation relationship. The results provide insight into the relationship of these nanoparticles with the matrix, which has implications for interpreting material properties as well as responses to radiation. - Highlights: • The oxide nanoparticles in a hafnium-containing austenitic ODS were characterized. • The nanoparticles are Y–Hf–Ti–O enriched phases according to APT and STEM–EDS. • Two coherency and an axis-parallel orientation relationships were found by HR-TEM. • Particle size has a prominent effect on the orientation relationship (OR). • Formation mechanism of the oxide nanoparticles was discussed based on the ORs

  20. An anode with aluminum doped on zinc oxide thin films for organic light emitting devices

    International Nuclear Information System (INIS)

    Doped zinc oxides are attractive alternative materials as transparent conducting electrode because they are nontoxic and inexpensive compared with indium tin oxide (ITO). Transparent conducting aluminum-doped zinc oxide (AZO) thin films have been deposited on glass substrates by DC reactive magnetron sputtering method. Films were deposited at a substrate temperature of 150-bar oC in 0.03 Pa of oxygen pressure. The electrical and optical properties of the film with the Al-doping amount of 2 wt% in the target were investigated. For the 300-nm thick AZO film deposited using a ZnO target with an Al content of 2 wt%, the lowest electrical resistivity was 4x10-4Ωcm and the average transmission in the visible range 400-700 nm was more than 90%. The AZO film was used as an anode contact to fabricate organic light-emitting diodes. The device performance was measured and the current efficiency of 2.9 cd/A was measured at a current density of 100 mA/cm2

  1. Oxidation Phase Diagram of Small Aluminum Clusters Based on First-Principles Calculations

    Science.gov (United States)

    Wang, Ligen; Kuklja, Maija

    2009-06-01

    It is important to understand the properties of individual nanometals before we can exploit their efficiency as energetic materials or as enhancement additives to other energetic formulations. In this paper, we construct the (p, T) phase diagram for the O/Al13 system based on first-principles atomistic thermodynamics. The temperature and pressure is taken into account via the oxygen chemical potential. The optimized Al13 cluster has an icosahedral shape. We find that O adsorption on the Al13 surface is site-specific; in particular, O adsorption at the bridge sites is most stable, whereas adsorption at the hollow sites is slightly unfavorable. For various oxygen adsorption layers, we determine the adsorption configurations/patterns by performing Monte Carlo calculations. We assume that the metal cluster becomes completely oxidized and calculate formation enthalpies of various oxidized metal clusters. The obtained phase diagram shows that an intact Al13 cluster is stable at the low O chemical potential range and the fully oxidized metal cluster is stable at the high O chemical potential range. However, the O adsorption phases are never thermodynamically stable. This study provides important insights into basic behavior of small aluminum clusters in the presence of oxygen, and may affect reliable predictions of behavior of Al-high explosive composites.

  2. Sediment toxicity and bioaccumulation of nano and micron-sized aluminum oxide.

    Science.gov (United States)

    Stanley, Jacob K; Coleman, Jessica G; Weiss, Charles A; Steevens, Jeffery A

    2010-02-01

    Nano-aluminum oxide (Al(2)O(3)) is used commercially in coatings and abrasives. Nano-Al(2)O(3) can also be generated through the oxidation of nano-aluminum in military propellants and energetics. The purpose of the present study was to assess toxicity and bioaccumulation of nano-Al(2)O(3) to a variety of sediment organisms (Tubifex tubifex, Hyalella azteca, Lumbriculus variegatus, and Corbicula fluminea). The bioaccumulation and toxicity of nano-Al(2)O(3) was compared with that of micron-sized Al(2)O(3) to investigate potential size-related effects. Results of the present study show species-specific differences in relative bioaccumulation of nano and micron-sized Al(2)O(3). Significant toxic effects (survival and growth) were observed in H. azteca testing, but only at high concentrations unlikely to be found in the environment. Nano-Al(2)O(3) was found to be more toxic than micron-sized Al(2)O(3) to H. azteca survival in a 14-d study in which organisms were in direct contact with a thin layer of 625 or 2,500 mg of Al(2)O(3) dispersed on the surface of either sediment or sand. A significant growth effect was also observed for nano but not micron-sized Al(2)O(3) at the highest treatment level tested (100 g/kg Al(2)O(3)) in a 10-d H. azteca bioassay in which Al(2)O(3) was homogenized with sediment. However, differences in measured sediment Al concentrations (micron-sized = 55.1 [+/-0.6] g/kg Al; nano-sized = 66.2 [+/-0.6] g/kg Al) in the nano and micron-sized Al(2)O(3) preclude direct comparison of the toxicity of these two treatments based on particle size. PMID:20821462

  3. Oxide and proton conductivity in aluminum-doped tricalcium oxy-silicate

    Energy Technology Data Exchange (ETDEWEB)

    Porras-Vazquez, J.M.; De la Torre, A.G.; Losilla, E.R.; Aranda, M.A.G. [Dept. Quimica Inorganica, Cristalografia y Mineralogia, Universidad de Malaga, Campus Teatinos, 29071-Malaga (Spain)

    2007-06-15

    Aluminum doping in tricalcium silicate, Ca{sub 3}(SiO{sub 4})O, has been studied by high-resolution laboratory X-ray powder diffraction and the Rietveld method. Two nominal series have been designed and studied. Oxygen-fixed Ca{sub 3-x/2}Al{sub x/2}(Si{sub 1-x/2}Al{sub x/2}O{sub 4})O series has been prepared as single-phase up to x = 0.03. However, oxygen-variable Ca{sub 3}(Si{sub 1-x}Al{sub x}O{sub 4})O{sub 1-x/2}{open_square}{sub x/2} series has not been stabilized for any composition. The samples show oxide anion conductivity with a small p-type electronic contribution under oxidizing conditions. Typical total conductivities for these solids are 10{sup -} {sup 5}-10{sup -} {sup 4}S cm{sup -} {sup 1} at 1100 K. The oxide ion transference numbers are very high, {proportional_to} 0.98, under reducing conditions, i.e. dry 5%H{sub 2}-N{sub 2}/air gradient. The oxide ion transference numbers are slightly lower, {proportional_to} 0.91 under oxidizing conditions, i.e. dry O{sub 2}/air gradient. These compounds display a very important proton contribution to the overall conductivities under humidified atmospheres. The proton transference number ranges between 0.72 and 0.55 at 873 and 1023 K, respectively. (author)

  4. Synthesis of tin oxide nanoparticle film by cathodic electrodeposition.

    Science.gov (United States)

    Kim, Seok; Lee, Hochun; Park, Chang Min; Jung, Yongju

    2012-02-01

    Three-dimensional SnO2 nanoparticle films were deposited onto a copper substrate by cathodic electrodeposition in a nitric acid solution. A new formation mechanism for SnO2 films is proposed based on the oxidation of Sn2+ ion to Sn4+ ion by NO+ ion and the hydrolysis of Sn4+. The particle size of SnO2 was controlled by deposition potential. The SnO2 showed excellent charge capacity (729 mAh/g) at a 0.2 C rate and high rate capability (460 mAh/g) at a 5 C rate. PMID:22630013

  5. Synthesis and Characterization of Holmium-Doped Iron Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Maarten Bloemen

    2014-02-01

    Full Text Available Rare earth atoms exhibit several interesting properties, for example, large magnetic moments and luminescence. Introducing these atoms into a different matrix can lead to a material that shows multiple interesting effects. Holmium atoms were incorporated into an iron oxide nanoparticle and the concentration of the dopant atom was changed in order to determine its influence on the host crystal. Its magnetic and magneto-optical properties were investigated by vibrating sample magnetometry and Faraday rotation measurements. The luminescent characteristics of the material, in solution and incorporated in a polymer thin film, were probed by fluorescence experiments.

  6. Synthesis and heating effect of iron/iron oxide composite and iron oxide nanoparticles

    Science.gov (United States)

    Zeng, Q.; Baker, I.; Loudis, J. A.; Liao, Y. F.; Hoopes, P. J.

    2007-02-01

    Fe/Fe oxide nanoparticles, in which the core consists of metallic Fe and the shell is composed of Fe oxides, were obtained by reduction of an aqueous solution of FeCl 3 within a NaBH 4 solution, or, using a water-in-oil micro-emulsion with CTAB as the surfactant. The reduction was performed either in an inert atmosphere or in air, and passivation with air was performed to produce the Fe/Fe 3O 4 core/shell composite. Phase identification and particle size were determined by X-ray diffraction and TEM. Thermal analysis was performed using a differential scanning calorimeter. The quasistatic magnetic properties were measured using a VSM, and the specific absorption rates (SARs) of both Fe oxide and Fe/Fe 3O 4 composite nanoparticles either dispersed in methanol or in an epoxy resin were measured by Luxtron fiber temperature sensors in an alternating magnetic field of 150 Oe at 250 kHz. It was found that the preparation conditions, including the concentrations of solutions, the mixing procedure and the heat treatment, influence the particle size, the crystal structure and consequently the magnetic properties of the particles. Compared with Fe oxides, the saturation magnetization (MS) of Fe/Fe 3O 4 particles (100-190 emu/g) can be twice as high, and the coercivity (H C) can be tunable from several Oe to several hundred Oe. Hence, the SAR of Fe/Fe 3O 4 composite nanoparticles can be much higher than that of Fe oxides, with a maximum SAR of 345 W/g. The heating behavior is related to the magnetic behavior of the nanoparticles.

  7. Functionalizing Aluminum Oxide by Ag Dendrite Deposition at the Anode during Simultaneous Electrochemical Oxidation of Al.

    Science.gov (United States)

    Rafailović, Lidija D; Gammer, Christoph; Rentenberger, Christian; Trišović, Tomislav; Kleber, Christoph; Karnthaler, Hans Peter

    2015-11-01

    A novel synthesis strategy is presented for depositing metallic Ag at the anode during simultaneous electrochemical oxidation of Al. This unexpected result is achieved based on galvanic coupling. Metallic dendritic nanostructures well-anchored in a high surface area supporting matrix are envisioned to open up a new avenue of applications. PMID:26398487

  8. Shifts in oxidation states of cerium oxide nanoparticles detected inside intact hydrated cells and organelles

    Energy Technology Data Exchange (ETDEWEB)

    Szymanski, Craig J.; Munusamy, Prabhakaran; Mihai, Cosmin; Xie, Yumei; Hu, Dehong; Gilles, Marry K.; Tyliszczak, T.; Thevuthasan, Suntharampillai; Baer, Donald R.; Orr, Galya

    2015-09-01

    Cerium oxide nanoparticles (CNPs) have been shown to induce diverse biological effects, ranging from toxic to beneficial. The beneficial effects have been attributed to the potential antioxidant activity of CNPs via certain redox reactions, depending on their oxidation state or Ce3+/Ce4+ ratio. However, this ratio is strongly dependent on the environment and age of the nanoparticles and it is unclear whether and how the complex intracellular environment impacts this ratio and the possible redox reactions of CNPs. To identify any changes in the oxidation state of CNPs in the intracellular environment and better understand their intracellular reactions, we directly quantified the oxidation states of CNPs outside and inside intact hydrated cells and organelles using correlated scanning transmission x-ray and super resolution fluorescence microscopies. By analyzing hundreds of small CNP aggregates, we detected a shift to a higher Ce3+/Ce4+ ratio in CNPs inside versus outside the cells, indicating a net reduction of CNPs in the intracellular environment. We further found a similar ratio in the cytoplasm and in the lysosomes, indicating that the net reduction occurs earlier in the internalization pathway. Together with oxidative stress and toxicity measurements, our observations identify a net reduction of CNPs in the intracellular environment, which is consistent with their involvement in potentially beneficial oxidation reactions, but also point to interactions that can negatively impact the health of cells.

  9. Comparative absorption, distribution, and excretion of titanium dioxide and zinc oxide nanoparticles after repeated oral administration

    OpenAIRE

    Cho, Wan-Seob; Kang, Byeong-Cheol; Lee, Jong Kwon; Jeong, Jayoung; Che, Jeong-Hwan; Seok, Seung H

    2013-01-01

    BACKGROUND:The in vivo kinetics of nanoparticles is an essential to understand the hazard of nanoparticles. Here, the absorption, distribution, and excretion patterns of titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles following oral administration were evaluated.METHODS:Nanoparticles were orally administered to rats for 13 weeks (7 days/week). Samples of blood, tissues (liver, kidneys, spleen, and brain), urine, and feces were obtained at necropsy. The level of Ti or Zn in each sam...

  10. Effect of Aluminum concentration on structural and optical properties of DC reactive magnetron sputtered Zinc Aluminum Oxide thin films for transparent electrode applications

    International Nuclear Information System (INIS)

    Zinc Aluminum Oxide(ZAO) thin films were deposited on glass substrates by DC reactive magnetron sputtering in an Ar+O2 gas mixture using commercial available Zn metal (99.99% purity) and Al (99.99% purity) targets of 2 inch diameter and 4 mm thickness. The films were characterized and the effect of aluminum (Al) concentration (2 at %-6 at %) on the structural and optical properties was studied. The average crystallite size obtained from Scherer formula is in the range of 32-44nm. Microstructural analysis using Scanning Electron Microscope (SEM) supplemented with EDS is carried out to find the grain size as well as to find the composition elemental data of prepared thin films. Optical study is performed to calculate the extinction coefficient (k), absorption coefficient (a), optical band gap (Eg) using transmission spectra obtained using UV-VIS-NIR spectrophotometer. There was widening of optical band gap with increasing aluminum concentration. ZAO film with low resistivity 3.2 × 10−4 cm and high transmittance of 80% is obtained for 3at% doped Al which is crucial for optoelectronic applications.

  11. Toxicity of metallic oxides nanoparticle suspensions to a freshwater sludge worm Tubifex tubifex Müller.

    Science.gov (United States)

    Verma, Surabhi; Das, Sangita; Khangarot, B S

    2011-02-01

    Toxic effects of selected metallic oxides nanoparticles were studied using the short-term static bioassays. Nanoparticles were more toxic than comparable bulk metallic oxides. Freshwater sludge worm Tubifex tubifex can be used as suitable test model for nanoecotoxicological studies in future studies. PMID:21485877

  12. Functional finishing in cotton fabrics using zinc oxide nanoparticles

    Indian Academy of Sciences (India)

    A Yadav; Virendra Prasad; A A Kathe; Sheela Raj; Deepti Yadav; C Sundaramoorthy; N Vigneshwaran

    2006-11-01

    Nanotechnology, according to the National Nanotechnology Initiative (NNI), is defined as utilization of structure with at least one dimension of nanometer size for the construction of materials, devices or systems with novel or significantly improved properties due to their nano-size. The nanostructures are capable of enhancing the physical properties of conventional textiles, in areas such as anti-microbial properties, water repellence, soil-resistance, anti-static, anti-infrared and flame-retardant properties, dyeability, colour fastness and strength of textile materials. In the present work, zinc oxide nanoparticles were prepared by wet chemical method using zinc nitrate and sodium hydroxide as precursors and soluble starch as stabilizing agent. These nanoparticles, which have an average size of 40 nm, were coated on the bleached cotton fabrics (plain weave, 30 s count) using acrylic binder and functional properties of coated fabrics were studied. On an average of 75%, UV blocking was recorded for the cotton fabrics treated with 2% ZnO nanoparticles. Air permeability of the nano-ZnO coated fabrics was significantly higher than the control, hence the increased breathability. In case of nano-ZnO coated fabric, due to its nano-size and uniform distribution, friction was significantly lower than the bulk-ZnO coated fabric as studied by Instron® Automated Materials Testing System. Further studies are under way to evaluate wash fastness, antimicrobial properties, abrasion properties and fabric handle properties.

  13. Synthesis of vanadium oxide nanoparticles and characterization by TEM

    International Nuclear Information System (INIS)

    We have synthesized vanadium oxide nanoparticles by thermal decomposition of vanadylacetylacetonate (VO(acac)2) on a highly oriented pyrolytic graphite substrate under Ar/H2 atmosphere. Particles were analyzed by high resolution transmission electron microscopy (HR-TEM) and atomic force microscopy (AFM). Chemical composition of the particles was confirmed by TEM energy dispersive x-ray analy sis (EDX). Our analysis shows that the degree of crystallinity as well as the morphology depends on the reaction parameters, e.g. temperature and concentration. For low concentrations of VO(acac)2 the particle size varies between 9 and 17 nm. With increasing concentration of VO(acac)2 the particle size increases and particle size distribution broadens. Particles with cubic section exhibit lattice spacing in agreement with V2O3. In addition, for high concentration samples, rod-like particles are found, which show a different crystalline vanadium oxide phase.

  14. Protein adsorption and cellular uptake of cerium oxide nanoparticles as a function of zeta potential

    OpenAIRE

    Patil, Swanand; Sandberg, Amanda; Heckert, Eric; Self, William; Seal, Sudipta

    2007-01-01

    The surface chemistry of biomaterials can have a significant impact on their performance in biological applications. Our recent work suggests that cerium oxide nanoparticles are potent antioxidants in cell culture models and we have evaluated several therapeutic applications of these nanoparticles in different biological systems. Knowledge of protein adsorption and cellular uptake will be very useful in improving the beneficial effects of cerium oxide nanoparticles in biology. In the present ...

  15. Biosynthesis of silver and zinc oxide nanoparticles using Pichia fermentans JA2 and their antimicrobial property

    Science.gov (United States)

    Chauhan, Ritika; Reddy, Arpita; Abraham, Jayanthi

    2015-01-01

    The development of eco-friendly alternative to chemical synthesis of metal nanoparticles is of great challenge among researchers. The present study aimed to investigate the biological synthesis, characterization, antimicrobial study and synergistic effect of silver and zinc oxide nanoparticles against clinical pathogens using Pichia fermentans JA2. The extracellular biosynthesis of silver and zinc oxide nanoparticles was investigated using Pichia fermentans JA2 isolated from spoiled fruit pulp bought in Vellore local market. The crystalline and stable metallic nanoparticles were characterized evolving several analytical techniques including UV-visible spectrophotometer, X-ray diffraction pattern analysis and FE-scanning electron microscope with EDX-analysis. The biosynthesized metallic nanoparticles were tested for their antimicrobial property against medically important Gram positive, Gram negative and fungal pathogenic microorganisms. Furthermore, the biosynthesized nanoparticles were also evaluated for their increased antimicrobial activities with various commercially available antibiotics against clinical pathogens. The biosynthesized silver nanoparticles inhibited most of the Gram negative clinical pathogens, whereas zinc oxide nanoparticles were able to inhibit only Pseudomonas aeruginosa. The combined effect of standard antibiotic disc and biosynthesized metallic nanoparticles enhanced the inhibitory effect against clinical pathogens. The biological synthesis of silver and zinc oxide nanoparticles is a novel and cost-effective approach over harmful chemical synthesis techniques. The metallic nanoparticles synthesized using Pichia fermentans JA2 possess potent inhibitory effect that offers valuable contribution to pharmaceutical associations.

  16. Microstructure and mechanical properties of aluminum alloy matrix composite reinforced with nano-particle MgO

    Energy Technology Data Exchange (ETDEWEB)

    Yar, A. Ansary, E-mail: arash_ansaryyar@yahoo.co [Department of Materials, Islamic Azad University, South Tehran Branch, P.O. Box 11365-4435, Tehran (Iran, Islamic Republic of); Montazerian, M.; Abdizadeh, H. [School of Metallurgy and Materials Engineering, University of Tehran, P.O. Box 11365-4563, Tehran (Iran, Islamic Republic of); Baharvandi, H.R. [Malek Ashtar University of Technology, P.O. Box 16765-3454, Tehran (Iran, Islamic Republic of)

    2009-09-18

    In this research, aluminum alloy (A356.1) matrix composites reinforced with 1.5, 2.5 and 5 vol% nano-particle MgO were fabricated via stir casting method. Fabrication was performed at various casting temperatures, viz. 800, 850 and 950 deg. C. Optimum amount of reinforcement and casting temperature were determined by evaluating the density, microstructure and mechanical properties of composites. The composites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Hardness and compression tests were carried out in order to identify mechanical properties. The results reveal that the composites containing 1.5 vol% reinforcement particle fabricated at 850 deg. C have homogenous microstructure as well as improved mechanical properties.

  17. Synthesis of aluminum nitride nanoparticles by a facile urea glass route and influence of urea/metal molar ratio

    International Nuclear Information System (INIS)

    Attention toward nanosized aluminum nitride (AlN) was rapidly increasing due to its physical and chemical characteristics. In this work, nanocrystalline AlN particles were prepared via a simple urea glass route. The effect of the urea/metal molar ratio on the crystal structure and morphology of nanocrystalline AlN particles was studied using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results revealed that the morphology and the crystal structure of AlN nanoparticles could be controlled by adjusting the urea/metal ratio. Furthermore, a mixture of Al2O3 and h-AlN was detected at the urea/metal molar ratio of 4 due to the inadequate urea content. With increasing the molar ratio, the pure h-AlN was obtained. In addition, the nucleation and growth mechanisms of AlN nanocrystalline were proposed.

  18. The synthesis and arrested oxidation of amorphous cobalt nanoparticles using DMSO as a functional solvent

    International Nuclear Information System (INIS)

    Magnetic nanoparticles exhibit a strong tendency to become overly oxidized and unstable during synthesis, ultimately leading to nanoparticle agglomeration and degradation. Capping agents can be used during nanoparticle synthesis to provide particle surface coverage and to improve nanoparticle dispersibility in solution, while preventing excessive oxidation and agglomeration. This paper presents a technique to synthesize amorphous 3.7 ± 1.5 nm cobalt (Co) nanoparticles using dimethyl sulfoxide (DMSO) to function as both the stabilizing agent and the solvent for Co nanoparticles via a quick, solvent-based reduction of Co2+ with NaBH4 in a DMSO solvent. UV–visible spectroscopy analysis was used to determine the minimum amount of reducing agent needed to produce Co nanoparticles so as to limit the waste of reagents. TEM and SEM imaging were used to study the morphology of the Co nanoparticles from the DMSO dispersion and of the Co nanoparticle powder. FT-IR was used to elucidate the nature of the interaction between the Co nanoparticle surface and DMSO. Furthermore, SEM–EDS elemental mapping was used to determine the composition and surface properties of the Co nanoparticles. This synthesis method demonstrates that Co nanoparticles can be successfully synthesized by simply using DMSO as a functional solvent, thereby avoiding excessive oxidation and agglomeration in solution

  19. Analysis of multilayered, nitrogen-doped aluminum oxide and hafnium oxide dielectric films for wide-temperature capacitor applications

    International Nuclear Information System (INIS)

    Capacitors with stable dielectric properties across a wide temperature range are a vital component in many power conditioning applications. High breakdown strength and low loss are also important for many applications. In this study, the dielectric properties of multilayer nitrogen-doped aluminum oxide and hafnium oxide films were characterized, comparing their properties to single layer films. The films were found to be stable from − 50 to 200 °C and from 20 Hz to 1 MHz. An order of magnitude decrease in leakage current was observed for the bilayer films. Breakdown strength for the multilayer films increased up to 75%. This concurs with the hypothesis that the addition of dielectric interfaces provides area to trap and dissipate runaway charge moving through the dielectric, thus lowering leakage current and increasing the breakdown strength. - Highlights: • Multilayer dielectric had stable dielectric properties for a wide temperature range. • Leakage current decreased an order of magnitude with layered dielectrics. • Breakdown strength increase of up to 75% was observed with layered dielectrics

  20. Long circulating reduced graphene oxide-iron oxide nanoparticles for efficient tumor targeting and multimodality imaging.

    Science.gov (United States)

    Xu, Cheng; Shi, Sixiang; Feng, Liangzhu; Chen, Feng; Graves, Stephen A; Ehlerding, Emily B; Goel, Shreya; Sun, Haiyan; England, Christopher G; Nickles, Robert J; Liu, Zhuang; Wang, Taihong; Cai, Weibo

    2016-07-01

    Polyethylene glycol (PEG) surface modification is one of the most widely used approaches to improve the solubility of inorganic nanoparticles, prevent their aggregation and prolong their in vivo blood circulation half-life. Herein, we developed double-PEGylated biocompatible reduced graphene oxide nanosheets anchored with iron oxide nanoparticles (RGO-IONP-(1st)PEG-(2nd)PEG). The nanoconjugates exhibited a prolonged blood circulation half-life (∼27.7 h) and remarkable tumor accumulation (>11 %ID g(-1)) via an enhanced permeability and retention (EPR) effect. Due to the strong near-infrared absorbance and superparamagnetism of RGO-IONP-(1st)PEG-(2nd)PEG, multimodality imaging combining positron emission tomography (PET) imaging with magnetic resonance imaging (MRI) and photoacoustic (PA) imaging was successfully achieved. The promising results suggest the great potential of these nanoconjugates for multi-dimensional and more accurate tumor diagnosis and therapy in the future. PMID:27109431

  1. Effect of Holding Time Before Solidification on Double-Oxide Film Defects and Mechanical Properties of Aluminum Alloys

    Science.gov (United States)

    El-Sayed, Mahmoud Ahmed; Salem, Hanadi A. G.; Kandeil, Abdelrazek Youssef; Griffiths, W. D.

    2011-12-01

    Double-oxide films (bifilms) have been held responsible for the variability in mechanical properties of aluminum castings. It has been suggested that the air entrapped inside a bifilm can react with the surrounding melt, leading to its consumption, which might improve the mechanical properties of the castings. In this work the effect of holding the melt before solidification on the distribution of mechanical properties, and by implication on entrained double oxide films, was investigated for several different aluminum alloys. The Weibull moduli of plate castings were determined under tensile conditions, and their fracture surfaces were examined for evidence of oxide films. The results suggested the occurrence of two competing mechanisms during the holding treatment: (1) the consumption of air inside the bifilms by reaction with the surrounding molten metal that may lead to improvements in mechanical properties and (2) the accompanying diffusion of hydrogen into the bifilms, which would be expected to have a deleterious effect on properties.

  2. Precipitation of Zinc Oxide Nanoparticles in Bicontinuous Microemulsions

    Directory of Open Access Journals (Sweden)

    Liliana E. Romo

    2011-01-01

    Full Text Available Zinc oxide nanoparticles were obtained directly, avoiding the calcination step, by precipitation at 70°C in bicontinuous microemulsions stabilized with a mixture of surfactants sodium bis (2-ethylhexyl sulfosuccinate/sodium dodecyl sulfate (2/1, wt./wt. containing 0.7 M zinc nitrate aqueous solution. Two concentrations of aqueous solution of precipitating agent sodium hydroxide were used under different dosing times on microemulsion. Characterization by X-ray diffraction and electron microscopy allowed us to identify particles with an acicular rod-like morphology and a hexagonal wurtzite crystal structure as small as 8.5 and 30 nm in average diameter and length, respectively. Productivities much higher than those typical in the preparation of zinc oxide nanoparticles via reverse microemulsions were obtained. Particle size was the same at the two studied sodium hydroxide concentrations, while it increases as dosing time of the precipitant agent increases. It is believed that the surfactant film on the microemulsion channels restricts the particle diameter growth.

  3. Electrochemical synthesis and photocatalytic property of cuprous oxide nanoparticles

    International Nuclear Information System (INIS)

    Cuprous oxide (Cu2O) nanoparticles of 35 nm in crystal size have been successfully synthesized via electrochemical method in alkali NaCl solutions with copper as electrodes and K2Cr2O7 as additive. Photocatalytic degradation of methyl orange (MeO) in aqueous Cu2O solution was investigated under either ultraviolet (UV) light or sunlight. X-ray diffraction (XRD), transmission electron microscopy (SEM), Fourier transformation infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-vis) and X-ray photoelectron spectroscopy (XPS) were introduced to characterize the samples. The results indicate that electric current shows no obvious effect on the growth of Cu2O nanocrystals and that 97% of MeO can be decolorized under UV irradiation for 2 h or under sunlight for 3 h when amount of Cu2O is 2 g/L. Recycling use of the catalyst revealed that Cu2O still has a high photocatalytic efficiency when repeatedly used for four times. Cu2O nanoparticles still kept its cubic crystal phase, but fractionally oxidized to be CuO after the photocatalysis. Compared with the original Cu2O nanoparticles, there has 1 eV shift of Cu 2p electron and 1.6 eV shift of Cu Auger signals for the Cu2O powders after four times photocatalysis. Some new peaks can also be observed at 401.1, 237.4 and 170.2 eV in the Cu2O powders after photocatalysis

  4. Solvothermal synthesis and characterization of monodisperse superparamagnetic iron oxide nanoparticles

    International Nuclear Information System (INIS)

    A series of magnetic iron oxide nanoparticle clusters with different structure guide agents were synthesized by a modified solvothermal method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analyses (TG), a vibrating sample magnetometer (VSM) and Fourier transform infrared spectroscopy (FTIR). It is found that the superparamagnetic nanoparticles guided by NaCit (sodium citrate) have high saturation magnetization (Ms) of 69.641 emu/g and low retentivity (Mr) of 0.8 emu/g. Guiding to form superparamagnetic clusters with size range of 80–110 nm, the adherent small-molecule citrate groups on the surface prevent the prefabricated ferrite crystals growing further. In contrast, the primary small crystal guided and stabilized by the PVP long-chain molecules assemble freely to larger ones and stop growing in size range of 100–150 nm, which has saturation magnetization (Ms) of 97.979 emu/g and retentivity (Mr) of 46.323 emu/g. The relevant formation mechanisms of the two types of samples are proposed at the end. The superparamagnetic ferrite clusters guided by sodium citrate are expected to be used for movement controlling of passive interference particles to avoid aggregation and the sample guided by PVP will be a candidate of nanometer wave absorbing material. - Highlights: • A facile synthesis of two kinds of monodisperse iron oxide nano-particle clusters was performed via a modified one-step solvothermal method in this work. • The NaCit and PVP as different guiding agents are used to control the formation and aggregation of nano-crystals during reacting and the ripening processes. • The superparamagnetic NaCit–Fe3O4 samples have high saturation magnetization (Ms) of 69.641 emu/g and low retentivity (Mr) of 0.8 emu/g. • The relevant formation mechanisms of the two types of samples are proposed

  5. Nanoplasmonic sensing and QCM-D as ultrasensitive complementary techniques for kinetic corrosion studies of aluminum nanoparticles

    Science.gov (United States)

    Schwind, Markus; Langhammer, Christoph; Kasemo, Bengt; Zorić, Igor

    2011-04-01

    Corrosion (oxidation) kinetics of Al nanodisks, 262 nm in diameter and 20 nm in height, was measured in degassed Milli-Q water at 23 °C and neutral pH by quartz crystal microbalance with dissipation monitoring (QCM-D) and nanoplasmonic sensing. The former detects the changes of the resonance frequency and the damping of the oscillation of a piezoelectric quartz crystal resonator. The latter detects the changes of the localized surface plasmon resonance (LSPR) in the metallic part of the Al nanoparticle, caused both by the shrinking metallic core and the changes in the dielectric environment as the oxide grows. Highly resolved kinetic data were obtained which show different corrosion stages. The two techniques yield complementary information not obtainable with one technique alone. Two main corrosion mechanisms, namely homogeneous oxide growth and nanoparticle fragmentation and roughening, are distinguished. The time dependence of the corrosion kinetics, determined using QCM-D, is in agreement with weight gain studies of bulk Al found in literature. The nanoplasmonic sensing measurements are compared to analytical model calculations of LSPR shifts which yield an estimate for the increase of oxide thickness during homogeneous oxide growth.

  6. Behavior of aluminum oxide, intermetallics and voids in Cu-Al wire bonds

    International Nuclear Information System (INIS)

    Nanoscale interfacial evolution in Cu-Al wire bonds during isothermal annealing from 175 deg. C to 250 deg. C was investigated by high resolution transmission electron microscopy (HRTEM). The native aluminum oxide film (∼5 nm thick) of the Al pad migrates towards the Cu ball during annealing. The formation of intermetallic compounds (IMC) is controlled by Cu diffusion, where the kinetics obey a parabolic growth law until complete consumption of the Al pad. The activation energies to initiate crystallization of CuAl2 and Cu9Al4 are 60.66 kJ mol-1 and 75.61 kJ mol-1, respectively. During IMC development, Cu9Al4 emerges as a second layer and grows together with the initial CuAl2. When Al is completely consumed, CuAl2 transforms to Cu9Al4, which is the terminal product. Unlike the excessive void growth in Au-Al bonds, only a few voids nucleate in Cu-Al bonds after long-term annealing at high temperatures (e.g., 250 oC for 25 h), and their diameters are usually in the range of tens of nanometers. This is due to the lower oxidation rate and volumetric shrinkage of Cu-Al IMC compared with Au-Al IMC.

  7. Tailoring defect structure and optical absorption of porous anodic aluminum oxide membranes

    International Nuclear Information System (INIS)

    Defects influence the optical and electronic properties of nanostructured materials that may be relevant for applications. In self-organized anodic aluminum oxide (AAO) templates we have investigated the effect of annealing, doping and nanoscale metal deposition. Optical absorption spectroscopy has been used as a sensitive probe for the defect density in AAO templates. The electronic spectra are found to be dominated by bands which originate from oxygen-deficient color centers (F+, F and F2). In annealing studies, the integrated absorption of the bands changes non-monotonically with annealing temperature and annealing time. This demonstrates that the concentration of defects can be optimized to tailor the optical properties of the AAO. Metallic Au wires are deposited in the template to establish a plasmonic template or array. The investigations provide an interesting insight into the interplay of reactivity and diffusivity on nanoscales. - Highlights: ► Preparation of metal wire arrays in oxide templates with tailored plasmonic properties. ► Oxygen defects are characterized using optical absorption and fluorescence. ► Optical absorption spectra are assigned to energy levels of oxygen vacancies (color centers). ► Annealing and electrodeposition of Au wires minimize defects maintaining the morphology.

  8. Aluminum-induced oxidative stress and neurotoxicity in grass carp (Cyprinidae--Ctenopharingodon idella).

    Science.gov (United States)

    Fernández-Dávila, María Lourdes; Razo-Estrada, Amparo Celene; García-Medina, Sandra; Gómez-Oliván, Leobardo Manuel; Piñón-López, Manuel Jesús; Ibarra, Rocio Guzmán; Galar-Martínez, Marcela

    2012-02-01

    Aluminum is used in a large number of anthropogenic processes, leading to aquatic ecosystems pollution. Diverse studies show that in mammals this metal may produce oxidative stress, is neurotoxic, and is involved in the development of neurodegenerative disorders, such as Alzhaimer's and Parkinson's diseases. Nevertheless, there are only few studies with respect to Al-induced neurotoxicity on aquatic fauna, particularly on fishes of economical interest, such as the grass carp (Ctenopharingodon idella). This study evaluates Al-induced toxicity on the grass carp C. idella. Specimens were exposed to the maximum concentration allowed in order to protect aquatic life (0.1 mg L⁻¹), for 12, 24, 48, 72 and 96 h. After the exposure time, lipid peroxidation degree, superoxide dismutase and catalase activity, as well as dopamine, adrenaline and noradrenaline levels were evaluated. Al concentration in organisms and water was also measured, in order to determine the bioconcentration factor. Results show that Al bioconcentrates in grass carp inducing oxidative stress (increment of 300 and 455 percent on lipid peroxidation degree and SOD activity, and decrement of 49 percent on CAT activity) and neurotoxicity (increment of 55 and 155 percent on dopamine and adrenaline levels and decrement of 93 percent on noradrenaline level). PMID:21993346

  9. Impact of water corrosion on nanoscale conductance on aluminum doped zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Hun; Lee, Hyunsoo; Choi, Sunghyun [Graduate School of EEWS (WCU) and Nanocentury KI, KAIST, Daejeon, 305-701 (Korea, Republic of); Center for Nanomaterials and Chemical Reactions, Institute for Basic Science, Daejeon, 305-701 (Korea, Republic of); Bae, Kyoung Hwan [The Thin Film Coating Team, KCC Corporation, Marbook Dong 83, Ki-Heung Gu, Yong-In City, 459-708 (Korea, Republic of); Park, Jeong Young, E-mail: jeongypark@kaist.ac.kr [Graduate School of EEWS (WCU) and Nanocentury KI, KAIST, Daejeon, 305-701 (Korea, Republic of)

    2013-11-29

    One major cause of failure in solar cell modules is associated with the degradation of conductive layers by the ingress of water. In this study, the corrosive interactions between water and transparent conducting oxides, including aluminum-doped ZnO (AZO) and indium tin oxide (ITO), were studied. The AZO layer exhibited ∼ 90% increase in sheet resistance from 17.5 to 33 ohm/square after an accelerated moisture test where the samples were stored at 80 °C and 100% humidity, while the conductivity of the ITO layer remained essentially unchanged. In order to elucidate the water-induced degradation mechanism of AZO, the structure and composition were characterized with conductive atomic force microscopy, energy dispersive spectrometry (EDS), and X-ray photoelectron spectroscopy (XPS) before and after the moisture test. It was found that the grain boundary of AZO exhibits a higher local conductance compared to that in the middle of the grain. A decrease in local conductance at the grain boundary after the moisture test was observed, which is attributed to depletion of the Zn, based on XPS and EDS analyses. - Highlights: • The moisture treatment lowers the local conductance of Al-doped ZnO (AZO). • Conductive atomic force microscopy shows the nanoelectronic properties of AZO. • Locally conductive areas are distributed along the grain boundaries. • The ratio of Zn to O along the grain boundaries was higher than that inside the grain.

  10. Evaluation of cerium oxide coated Cu cermets as inert anodes for aluminum electrowinning

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

    Cu/NiFe{sub 2}O{sub 4} cermets were evaluated, with and without an in-situ deposited CEROX (TM; cerium oxide) coating, in 100 h laboratory A1 electrowinning tests. Bath ratio and current density were varied between tests and corrosion was determined by contamination of the aluminum and cryolite by cermet components (Cu, Fe, and Ni). Higher bath ratios of 1.5 to 1.6 led to less corrosion and thicker CEROX coatings. Lower current densities led to slightly less corrosion but much less oxidation of the Cu cermet substrate. At identical test conditions, the corrosion of the CEROX coated cermets was 1/7 that of an uncoated cermet. Corrosion was increased in CEROX coated cermets tested under unsaturated alumina conditions. The electrical conductivity of the CEROX coating was measured to be {approximately}0.2 ohm{sup {minus}1}cm{sup {minus}1}, resulting in a slight voltage penalty, depending on the thickness of the coating.

  11. Application of a palladium hexacyanoferrate film-modified aluminum electrode to electrocatalytic oxidation of hydrazine.

    Science.gov (United States)

    Razmi, Habib; Azadbakht, Azadeh; Sadr, Moayad Hossaini

    2005-11-01

    A palladium hexacyanoferrate (PdHCF) film as an electrocatalytic material was obtained at an aluminum (Al) electrode by a simple electroless dipping method. The modified Al electrode demonstrated a well-behaved redox couple due to the redox reaction of the PdHCF film. The PdHCF film showed an excellent electrocatalytic activity toward the oxidation of hydrazine. The electrocatalytic oxidation of hydrazine was studied by cyclic voltammetry and rotating disk electrode voltammetry techniques. A calibration graph obtained for the hydrazine consisted of two segments (localized at concentration ranges 0.39-10 and 20-75 mM). The rate constant k and transfer coefficient alpha for the catalytic reaction and the diffusion coefficient of hydrazine in the solution D, were found to be 3.11 x 10(3) M(-1) s(-1), 0.52 and 8.03 x 10(-6) cm2 s(-1) respectively. The modified electrode was used to amperometric determination of hydrazine in photographic developer. The interference of ascorbic acid and thiosulfate were investigated and greatly reduced using a thin film of Nafion on the modified electrode. The modified electrode indicated reproducible behavior and a high level of stability during electrochemical experiments, making it particularly suitable for analytical purposes. PMID:16317900

  12. Behavior of aluminum oxide, intermetallics and voids in Cu-Al wire bonds

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H., E-mail: HXu14@bama.ua.edu [Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); Liu, C.; Silberschmidt, V.V. [Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU (United Kingdom); Pramana, S.S. [School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); White, T.J. [School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); Centre for Advanced Microscopy, Australian National University, Canberra, ACT 2601 (Australia); Chen, Z. [School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); Acoff, V.L. [Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States)

    2011-08-15

    Nanoscale interfacial evolution in Cu-Al wire bonds during isothermal annealing from 175 deg. C to 250 deg. C was investigated by high resolution transmission electron microscopy (HRTEM). The native aluminum oxide film ({approx}5 nm thick) of the Al pad migrates towards the Cu ball during annealing. The formation of intermetallic compounds (IMC) is controlled by Cu diffusion, where the kinetics obey a parabolic growth law until complete consumption of the Al pad. The activation energies to initiate crystallization of CuAl{sub 2} and Cu{sub 9}Al{sub 4} are 60.66 kJ mol{sup -1} and 75.61 kJ mol{sup -1}, respectively. During IMC development, Cu{sub 9}Al{sub 4} emerges as a second layer and grows together with the initial CuAl{sub 2}. When Al is completely consumed, CuAl{sub 2} transforms to Cu{sub 9}Al{sub 4}, which is the terminal product. Unlike the excessive void growth in Au-Al bonds, only a few voids nucleate in Cu-Al bonds after long-term annealing at high temperatures (e.g., 250 {sup o}C for 25 h), and their diameters are usually in the range of tens of nanometers. This is due to the lower oxidation rate and volumetric shrinkage of Cu-Al IMC compared with Au-Al IMC.

  13. Silicon effects on formation of EPO oxide coatings on aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang, L. [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Windsor, ON, N9B 3P4 (Canada); Nie, X. [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Windsor, ON, N9B 3P4 (Canada)]. E-mail: xnie@uwindsor.ca

    2006-01-03

    Electrolytic plasma processes (EPP) can be used for cleaning, metal-coating, carburizing, nitriding, and oxidizing. Electrolytic plasma oxidizing (EPO) is an advanced technique to deposit thick and hard ceramic coatings on a number of aluminum alloys. However, the EPO treatment on Al-Si alloys with a high Si content has rarely been reported. In this research, an investigation was conducted to clarify the effects of silicon contents on the EPO coating formation, morphology, and composition. Cast hypereutectic 390 alloys ({approx} 17% Si) and hypoeutectic 319 alloys ({approx} 7% Si) were chosen as substrates. The coating morphology, composition, and microstructure of the EPO coatings on those substrates were investigated using scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD). A stylus roughness tester was used for surface roughness measurement. It was found that the EPO process had four stages where each stage was corresponding to various coating surface morphology, composition, and phase structures, characterised by different coating growth mechanisms.

  14. Microwave-assisted and liquid oxidation combination techniques for the preparation of nickel oxide nanoparticles

    International Nuclear Information System (INIS)

    A nickel hydroxide, Ni(OH)2, was prepared by microwave-assisted heating technique from nickel nitrate aqueous solution and sodium hydroxide (assigned as PM). Then, the as-prepared PM was oxidized by liquid oxidation with sodium hypochlorite (assigned as PMO). Further, pure nanocrystalline nickel oxide (NiO) particles were obtained from the as-prepared PMO by calcination at 300, 400, 500, 600, 650 and 700 deg. C (labeled as C300, C400, C500, C600, C650 and C700, respectively). The as-prepared powders (PM and PMO) and the NiO nanoparticles were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), temperature-programmed reduction (TPR) and scanning electron microscope (SEM). The results indicated that the particle size of nickel oxide was controlled by the calcined temperature. The average crystal size of the NiO nanoparticles ranges from about 5 to 35 nm at 300-700 deg. C. Mechanism of nickel oxide nanocrystallite growth during thermal treatment was investigated

  15. Interactive effect of cerium and aluminum on the ignition point and the oxidation resistance of magnesium alloy

    International Nuclear Information System (INIS)

    This paper focused on the interactive effect of cerium (Ce) addition and aluminum (Al) content in magnesium alloy on ignition point and oxidation resistance. Ce content played an important role in improving the oxidation resistance of Mg alloy. Ignition point ascended with increasing Ce content. 0.25 wt% Ce content in Mg alloys could greatly improve tightness of the oxide film of Mg alloys. However, when Ce content in the alloy exceeded its solid solubility, ignition point descended. Furthermore, Al content in the alloy also influenced the ignition point. The higher the Al content was, the lower the ignition point

  16. Nitric oxide releasing iron oxide magnetic nanoparticles for biomedical applications: cell viability, apoptosis and cell death evaluations

    International Nuclear Information System (INIS)

    Nitric oxide (NO) is involved in several physiological and pathophysiological processes, such as control of vascular tone and immune responses against microbes. Thus, there is great interest in the development of NO-releasing materials to carry and deliver NO for biomedical applications. Magnetic iron oxide nanoparticles have been used in important pharmacological applications, including drug-delivery. In this work, magnetic iron oxide nanoparticles were coated with thiol-containing hydrophilic ligands: mercaptosuccinic acid (MSA) and dimercaptosuccinic acid (DMSA). Free thiol groups on the surface of MSA- or DMSA- coated nanoparticles were nitrosated, leading to the formation of NO-releasing iron oxide nanoparticles. The cytotoxicity of MSA- or DMSA-coated magnetic nanoparticles (MNP) (thiolated nanoparticles) and nitrosated MSA- or nitrosated DMSA- coated MNPs (NO-releasing nanoparticles) were evaluated towards human lymphocytes. The results showed that MNP-MSA and MNP-DMSA have low cytotoxicity effects. On the other hand, NO-releasing MNPs were found to increase apoptosis and cell death compared to free NO-nanoparticles. Therefore, the cytotoxicity effects observed for NO-releasing MNPs may result in important biomedical applications, such as the treatment of tumors cells.

  17. Magnetic iron oxide nanoparticles as drug delivery system in breast cancer

    International Nuclear Information System (INIS)

    Present work was focused on producing improved iron oxide nanoparticles for targeted drug delivery in breast cancer. Nanometric-sized iron oxide particles were synthesized by laser pyrolysis and were morphologically/structurally characterized. These new nanoparticles were compared with some commercial, chemically prepared iron oxide ones. Cytotoxicity and the anti-proliferation effects of nanoparticles were tested in vitro on the breast adenocarcinoma cell line MCF-7. Nanoparticles were further coated with the antracyclinic antibiotic Violamycine B1 and tested for the anti-tumor effect on MCF-7 cells. The nanoparticles produced by us seem more effective in vitro than the commercial ones, with respect to cellular uptake and VB1 delivery. Violamycine B1 bound on nanoparticles is as efficient as the free form, but is better delivered into tumor cells.

  18. Photosensitizer decorated iron oxide nanoparticles: bimodal agent for combined hyperthermia and photodynamic therapy

    Science.gov (United States)

    Yang, Zhimou; Xu, Keming; Zhang, Bei; Xu, Bing; Zhang, Xixiang; Chang, Chi K.

    2006-02-01

    As the PDT effect may be enhanced by localized hyperthermia (HT), it would be logical to find a single agent that could bring about these two modalities at precisely the target site for synergism. Since highly localized HT can be induced by magnetic field excitation of superparamagnetic nanoparticles, we report here the design and synthesis of photosensitizer-decorated iron oxide nanoparticles and their tumoricidal effect. Thus, a porphyrin is covalently anchored on the iron oxide nanoparticle via dihydroxybenzene which binds tightly on the surface of the nanoparticle by M-O bond. The morphology of the resultant nanoparticle was studied to show that the crystallinality is not changed and the nanoparticle remains superparamagnetic at room temperature. The conjugate is also strongly fluorescent indicating that the iron oxide hardly affects the optical properties of the surface bound porphyrin moieties. The conjugate is readily taken by cancer cell (Hela cell line) and is able to trigger apoptosis after excitation by light.

  19. Shape control of the magnetic iron oxide nanoparticles under different chain length of reducing agents

    Energy Technology Data Exchange (ETDEWEB)

    Ngoi, Kuan Hoon; Chia, Chin-Hua, E-mail: chia@ukm.edu.my; Zakaria, Sarani [School of Applied Physics, Faculty Science and Technology, University Kebangsaan Malaysia 43600 UKM Bangi, Selangor (Malaysia); Chiu, Wee Siong [Low Dimensional Materials Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Lembah Pantai, Kuala Lumpur (Malaysia)

    2015-09-25

    We report on the effect of using reducing agents with different chain-length on the synthesis of iron oxide nanoparticles by thermal decomposition of iron (III) acetylacetonate in 1-octadecene. This modification allows us to control the shape of nanoparticles into spherical and cubic iron oxide nanoparticles. The highly monodisperse 14 nm spherical nanoparticles are obtained under 1,2-dodecanediol and average 14 nm edge-length cubic iron oxide nanoparticles are obtained under 1,2-tetradecanediol. The structural characterization such as transmission electron microscope (TEM) and X-ray diffraction (XRD) shows similar properties between two particles with different shapes. The vibrating sample magnetometer (VSM) shows no significant difference between spherical and cubic nanoparticles, which are 36 emu/g and 37 emu/g respectively and superparamagnetic in nature.

  20. Biocidal effects of silver and zinc oxide nanoparticles on the bioluminescent bacteria

    Science.gov (United States)

    Taran, M. V.; Starodub, N. F.; Katsev, A. M.; Guidotti, M.; Khranovskyy, V. D.; Babanin, A. A.; Melnychuk, M. D.

    2013-11-01

    The effect of silver and zinc oxide nanoparticles in combination with alginate on bioluminescent Photobacterium leiognathi Sh1 bacteria was investigated. Silver nanoparticles were found to be more toxic than zinc oxide nanoparticles on bioluminescent bacteria. The nanoparticles and their ions released results in the same effect, however, it was absent in combination with alginate. The effective inhibiting concentration (EC50) for silver nanoparticles was found about 0.3 - 0.4 μg mL-1, which was up to two times larger then for zinc oxide nanoparticles. The absence of sodium chloride in the tested media prevented the formation of colloidal particles of larger size and the effective inhibition concentrations of metal derivatives were lower than in the presence of sodium chloride.