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Sample records for active coated nano-particle

  1. Electromagnetics of active coated nano-particles

    Arslanagic, Samel

    2013-01-01

    This work reviews the fundamental properties of several spherical and cylindrical active coated nano-particles excited by their respective single and/or multiple sources of radiation at optical frequencies. Particular attention is devoted to the influence of the source location and orientation, t...

  2. Electromagnetics of active coated nano-particles

    Arslanagic, Samel

    This work reviews the fundamental properties of several spherical and cylindrical active coated nano-particles excited by their respective single and/or multiple sources of radiation at optical frequencies. Particular attention is devoted to the influence of the source location and orientation, the...... optical gain constant and the nano-particle material composition on the electric and magnetic near fields, the power flow density, the radiated power as well as the directivities. Resonant as well as quasi-transparent states will be emphasized in the discussion....

  3. Directive properties of active coated nano-particles

    Arslanagic, Samel; Ziolkowski, W.

    2012-01-01

    The directivities of the fields radiated by a variety of cylindrical and spherical active coated nano-particles, which are excited by their respective sources of illumination at optical frequencies, are investigated. Particular attention is devoted to the influence of the source location and...

  4. Active coated nano-particle excited by an arbitrarily located electric Hertzian dipole — resonance and transparency effects

    Arslanagic, Samel; Ziolkowski, Richard W.

    2010-01-01

    The present work investigates the optical properties of active coated spherical nano-particles excited by an arbitrarily located electric Hertzian dipole. The nano-particles are made of specific dielectric and plasmonic materials. The spatial near-field distribution as well as the normalized radi......-radiating/transparent states of the active coated nano-particle are identified. Implications of both the resonant and non-radiating states on the previously proposed localized sensors based on the active coated nano-particle will also be considered here....

  5. Nano-sensing of the orientation of fluorescing molecules with active coated nano-particles

    Arslanagic, Samel; Ziolkowski, Richard W.

    2015-01-01

    The potential of using active coated nano-particles to determine the orientation of fluorescing molecules is reported. By treating each fluorescing molecule as an electric Hertzian dipole, single and multiple fluorescing molecules emitting coherently and incoherently in various orientations are...

  6. Cylindrical active coated nano-particles excited by electric and magnetic line sources

    Arslanagic, Samel; Liu, Y.; Malureanu, Radu;

    2011-01-01

    Cylindrical active coated nano-particles comprised of a silica nano-cylinder core covered with a plasmonic nano-shell are investigated with regard to their near- and far-field properties. The source of excitation is taken to be an electric or a magnetic line current, while three different plasmonic...

  7. Impact of the Excitation Source and Plasmonic Material on Cylindrical Active Coated Nano-Particles

    Richard W. Ziolkowski

    2011-09-01

    Full Text Available Electromagnetic properties of cylindrical active coated nano-particles comprised of a silica nano-cylinder core layered with a plasmonic concentric nano-shell are investigated for potential nano-sensor applications. Particular attention is devoted to the near-field properties of these particles, as well as to their far-field radiation characteristics, in the presence of an electric or a magnetic line source. A constant frequency canonical gain model is used to account for the gain introduced in the dielectric part of the nano-particle, whereas three different plasmonic materials (silver, gold, and copper are employed and compared for the nano-shell layers.

  8. Spherical active coated nano-particles – impact of the electric Hertzian dipole orientation

    Arslanagic, Samel; Mostafavi, M.; Malureanu, Radu; Ziolkowski, R. W.

    2011-01-01

    Spherical active coated nano-particles comprised of a silica nano-cylinder core covered with a plasmonic nano-shell are investigated with regard to their near- and far-field properties. The source of excitation is taken to be that of a tangential or a radial electric Hertizan dipole while three...... different plasmonic materials are employed for the nano-shells, namely silver, gold and copper....

  9. Impact of the Excitation Source and Plasmonic Material on Cylindrical Active Coated Nano-Particles

    Ziolkowski, Richard W.; Radu Malureanu; Samel Arslanagic; Yan Liu

    2011-01-01

    Electromagnetic properties of cylindrical active coated nano-particles comprised of a silica nano-cylinder core layered with a plasmonic concentric nano-shell are investigated for potential nano-sensor applications. Particular attention is devoted to the near-field properties of these particles, as well as to their far-field radiation characteristics, in the presence of an electric or a magnetic line source. A constant frequency canonical gain model is used to account for the gain introduced ...

  10. Coated nano-particle jamming of quantum emitters

    Arslanagic, Samel; Ziolkowski, Richard W.

    2012-01-01

    Spherical active coated nano-particles are examined analytically and numerically in the presence of one, two or four quantum emitters (electric Hertzian dipoles). The ability of the coated nano-particle to effectively cloak the emitters to a far-field observer is reported. This offers an...

  11. Stacked dipole line source excitation of active nano-particles

    Arslanagic, Samel

    This work investigates electromagnetic properties of cylindrical active coated nano-particles excited by a stac- ked electric dipole line source. The nano-particles consist of a silica nano-core, layered by silver, gold, or copper nano-shell. Attention is devoted to the influence of the source...... location and dipole orientation, the gain constant, and the nano-particle material composition on the electromagnetic field distributions and radiated powers. The results are contrasted to those for the magnetic line source illumination of the nano-particles....

  12. Impact of the Excitation Source and Plasmonic Material on Cylindrical Active Coated Nano-Particles

    Arslanagic, Samel; Liu, Yan; Malureanu, Radu; Ziolkowski, Richard W.

    2011-01-01

    well as to their far-field radiation characteristics, in the presence of an electric or a magnetic line source. A constant frequency canonical gain model is used to account for the gain introduced in the dielectric part of the nano-particle, whereas three different plasmonic materials (silver, gold......, and copper) are employed and compared for the nano-shell layers....

  13. A comparative study of resonant effects in two-dimensional active coated nano-particles of circular, polygonal, and elliptical shapes

    B.-Jørgensen, Mikkel; Kaminski, Piotr Marek; Ziolkowski, Richard W.;

    and plasmonic structures. In regards to the latter, extensive analytical and numerical investigations were conducted on the theoretical designs of nano-antennas by use of passive and active coated nano-particles (CNPs) of various shapes and excitations. It was demonstrated that specifically designed active CNPs...

  14. Oleic acid coated magnetic nano-particles: Synthesis and characterizations

    Panda, Biswajit, E-mail: bpanda@mes.ac.in; Goyal, P. S. [Pillai’s Institute of Information Technology, Engineering, Media Studies and Research, Dr. K. M. Vasudevan Pillai’s Campus, New Panvel, 410 206 (India)

    2015-06-24

    Magnetic nano particles of Fe{sub 3}O{sub 4} coated with oleic acid were synthesized using wet chemical route, which involved co-precipitation of Fe{sup 2+} and Fe{sup 3+} ions. The nano particles were characterized using XRD, TEM, FTIR, TGA and VSM. X-ray diffraction studies showed that nano particles consist of single phase Fe{sub 3}O{sub 4} having inverse spinel structure. The particle size obtained from width of Bragg peak is about 12.6 nm. TEM analysis showed that sizes of nano particles are in range of 6 to 17 nm with a dominant population at 12 - 14 nm. FTIR and TGA analysis showed that -COOH group of oleic acid is bound to the surface of Fe{sub 3}O{sub 4} particles and one has to heat the sample to 278° C to remove the attached molecule from the surface. Further it was seen that Fe{sub 3}O{sub 4} particles exhibit super paramagnetism with a magnetization of about 53 emu/ gm.

  15. Oleic acid coated magnetic nano-particles: Synthesis and characterizations

    Magnetic nano particles of Fe3O4 coated with oleic acid were synthesized using wet chemical route, which involved co-precipitation of Fe2+ and Fe3+ ions. The nano particles were characterized using XRD, TEM, FTIR, TGA and VSM. X-ray diffraction studies showed that nano particles consist of single phase Fe3O4 having inverse spinel structure. The particle size obtained from width of Bragg peak is about 12.6 nm. TEM analysis showed that sizes of nano particles are in range of 6 to 17 nm with a dominant population at 12 - 14 nm. FTIR and TGA analysis showed that -COOH group of oleic acid is bound to the surface of Fe3O4 particles and one has to heat the sample to 278° C to remove the attached molecule from the surface. Further it was seen that Fe3O4 particles exhibit super paramagnetism with a magnetization of about 53 emu/ gm

  16. Fabricating bio-inspired micro/nano-particles by polydopamine coating and surface interactions with blood platelets

    Ye, Wei [Jiangsu Provincial Key Lab for Interventional Medical Devices, Huaiyin Institute of Technology, Huaian 223003 (China); State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Shi, Qiang, E-mail: shiqiang@ciac.ac.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Hou, Jianwen; Gao, Jian; Li, Chunming; Jin, Jing; Shi, Hengchong [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Yin, Jinghua, E-mail: yinjh@ciac.ac.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2015-10-01

    Graphical abstract: The particles or particle aggregations activate the blood platelets and provide the physical adhesive sites for platelets adhesion. - Highlights: • Particles with varied sizes and surface properties were fabricated by facile polydopamine (PDA) coating on polystyrene microsphere. • The direct interaction between PDA particles and blood platelets was qualitatively investigated. • The knowledge on platelet–particle interactions provided the basic principle to select biocompatible micro/nano-particles in biomedical field. - Abstract: Although bio-inspired polydopamine (PDA) micro/nano-particles show great promise for biomedical applications, the knowledge on the interactions between micro/nano-particles and platelets is still lacking. Here, we fabricate PDA-coated micro/nano-particles and investigate the platelet–particle surface interactions. Our strategy takes the advantage of facile PDA coating on polystyrene (PS) microsphere to fabricate particles with varied sizes and surface properties, and the chemical reactivity of PDA layers to immobilize fibrinogen and bovine serum albumin to manipulate platelet activation and adhesion. We demonstrate that PS particles activate the platelets in the size-dependent manner, but PDA nanoparticles have slight effect on platelet activation; PS particles promote platelet adhesion while PDA particles reduce platelet adhesion on the patterned surface; Particles interact with platelets through activating the glycoprotein integrin receptor of platelets and providing physical sites for initial platelet adhesion. Our work sheds new light on the interaction between platelets and particles, which provides the basic principle to select biocompatible micro/nano-particles in biomedical field.

  17. Fabricating bio-inspired micro/nano-particles by polydopamine coating and surface interactions with blood platelets

    Graphical abstract: The particles or particle aggregations activate the blood platelets and provide the physical adhesive sites for platelets adhesion. - Highlights: • Particles with varied sizes and surface properties were fabricated by facile polydopamine (PDA) coating on polystyrene microsphere. • The direct interaction between PDA particles and blood platelets was qualitatively investigated. • The knowledge on platelet–particle interactions provided the basic principle to select biocompatible micro/nano-particles in biomedical field. - Abstract: Although bio-inspired polydopamine (PDA) micro/nano-particles show great promise for biomedical applications, the knowledge on the interactions between micro/nano-particles and platelets is still lacking. Here, we fabricate PDA-coated micro/nano-particles and investigate the platelet–particle surface interactions. Our strategy takes the advantage of facile PDA coating on polystyrene (PS) microsphere to fabricate particles with varied sizes and surface properties, and the chemical reactivity of PDA layers to immobilize fibrinogen and bovine serum albumin to manipulate platelet activation and adhesion. We demonstrate that PS particles activate the platelets in the size-dependent manner, but PDA nanoparticles have slight effect on platelet activation; PS particles promote platelet adhesion while PDA particles reduce platelet adhesion on the patterned surface; Particles interact with platelets through activating the glycoprotein integrin receptor of platelets and providing physical sites for initial platelet adhesion. Our work sheds new light on the interaction between platelets and particles, which provides the basic principle to select biocompatible micro/nano-particles in biomedical field

  18. Jointing of Coated Conductors by Using Nano-particle Metal Pastes

    Nakanishi, Tsuyoshi; Machi, Takato; Izumi, Teruo; Teranishi, Ryo; Kato, Tomohiro; Kato, Takeharu; Hirayama, Tsukasa

    Development of a jointing technique of coated conductors is important for all applications, such as superconducting magnets, cables, etc. Low resistance jointing techniques by means of silver diffusion [1] and for superconducting joints[2] have been reported so far. Since these processes were carried out at higher temperatures than the O2 annealing temperature for appropriate carrier doping to the REBa2Cu3O7-d (REBCO) crystals and resulted in oxygen deficiency in the REBCO crystals, long time O2 annealing was required for compensation of this oxygen deficiency. Because the long time and high temperature post annealing is an inappropriate process as on-site technology, solder jointing technology has been widely accepted, in general, for practical applications. However, the resistance of the solder joint is 50 - 100 nΩ, and then the Joule heat generation in the joint region is a serious problem and must be solved. Consequently, we have studied a new jointing technique by using the pastes containing of silver or gold nano-particles. Because the Ic value of GdBCO was deteriorated with higher temperature heat treatment, we have tried to develop a jointing technology with the low temperature (below 200°C). We used the nano-particle metal pastes (∼5 nm) which contained dispersants around the chemically active surface of nano-particles and dissociates at low temperatures and achieved the low resistance joint (∼ 3nΩ, 10 x 160 mm2, 77 K) as well as no Ic degradation without O2 post annealing.

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

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

    2010-01-01

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

  20. In vitro biological performance of nano-particles on the surface of hydroxyapatite coatings

    The biocompatibility of a kind of heat-treated bilayer hydroxyapatite (HA) coatings with nano-particles was investigated, mainly in terms of the immersion in simulated body fluid (SBF) and osteoblast adhesion. Scanning electron microscopy (SEM) was used to observe the morphology of coatings and cellular adhesion. The phases present in the coatings were determined by X-ray diffraction (XRD). Calcium ion (Ca2+) concentration in SBF was measured by Atomic absorption spectrophotometer. The results show nano-HA heat-treated at 650 deg. C for 0.5 h (BBCs) is comparatively stable during immersion in SBF and favor of the adhesion of osteoblasts. Cellular filopodia adhere firmly to the nano-particles and stretch in various direction

  1. In vitro biological performance of nano-particles on the surface of hydroxyapatite coatings

    Chen, Y. M.; Xi, T. F.; Lv, Y. P.; Zheng, Y. D.

    2008-11-01

    The biocompatibility of a kind of heat-treated bilayer hydroxyapatite (HA) coatings with nano-particles was investigated, mainly in terms of the immersion in simulated body fluid (SBF) and osteoblast adhesion. Scanning electron microscopy (SEM) was used to observe the morphology of coatings and cellular adhesion. The phases present in the coatings were determined by X-ray diffraction (XRD). Calcium ion (Ca 2+) concentration in SBF was measured by Atomic absorption spectrophotometer. The results show nano-HA heat-treated at 650 °C for 0.5 h (BBCs) is comparatively stable during immersion in SBF and favor of the adhesion of osteoblasts. Cellular filopodia adhere firmly to the nano-particles and stretch in various direction.

  2. Acoustic Emission Monitoring of Compression-after-Impact Test of Nano-Particles-Coated CFRP Damaged by Simulated Lightning Strikes

    Nanoparticles-coated and impact-damaged carbon-fiber reinforced plastics(CFRP) laminates were tested under compression-after-impact(CAI) mode and the propagation of damage due to compressive loading has been monitored by acoustic emission(AE). The impact damage was induced not by mechanical loading but by a simulated lightning strike. CFRP laminates were made of carbon prepregs prepared by coating of conductive nano-particles directly on the fibers and the coupons were subjected to simulated lightning strikes with a high voltage/current impulse of 10∼40 kA within a few microseconds. The effects of nano-particles coating and the degree of damage induced by the simulated lightning strikes on the AE activities were examined, and the relationship between the compressive residual strength and AE behavior has been evaluated in terms of AE event counts and the onset of AE activity with the compressive loading. The degree of impact damage was also measured in terns of damage area by using ultrasonic C-scan images. From the results assessed during the CAI tests of damaged CFRP showed that AE monitoring appeared to be very useful to differentiate the degree of damage hence the mechanical integrity of composite structures damaged by lightning strikes

  3. Influence of active nano particle size and material composition on multiple quantum emitter enhancements: Their Enhancement and Jamming Effects

    Arslanagic, Samel; Ziolkowski, Richard W.

    2014-01-01

    active coated nano-particles are examined here theoretically with regard to their ability to effectively enhance or jam the responses of quantum emitters, e.g., fluorescing molecules, and nano- antennas to an observer located in their far-field regions. The investigated spherical particles consist of a...... gain-impregnated silica nano-core covered with a nano-shell of a specific plasmonic material. Attention is devoted to the influence of the over-all size of these particles and their material composition on the obtained levels of active enhancement or jamming. Silver, gold and copper are employed as...... their nano- shells. The over-all diameters of the investigated coated nano-particles are taken to be 20 nm, 40 nm, and 60 nm, while maintaining the same ratio of the core radius and shell thickness. It is shown that the jamming levels, particularly when several emitters are present, are significantly...

  4. Synthesis and characterization of Gold and Silver nano-particles using different leaf extracts namely Catharanthus roseus, Datura metel and Azadirachta indica and Estimation of antimicrobial activity of silver nano-particles using disc diffusion method

    Sarbjeet Singh Gujral

    2014-12-01

    Full Text Available Objective: synthesis of gold and silver nano-particles using leaf extracts of Catharanthus roseus, Datura metel and Azadirachta indica and Estimation of antimicrobial activity of silver nano-particles using disc diffusion method. Method: Green approach has been utilized for the synthesis of gold and silver nano-particles. Different aqueous plant extracts has been prepared which was then utilized for the biosynthesis of gold and silver nano-particles. Estimation for the synthesis of nano-particles were done using UV-Visible spectroscopy and Fourier- Transform infrared spectroscopy. Antimicrobial activity of silver nano-particles prepared using aqueous neem extract was investigated using disc diffusion method. Result: UV- Vis spectroscopy of prepared nano-particles was done which gave a peak at about 550 nm for gold nano-particles and around 430 nm for silver nano-particles. FTIR of collected nano-particles gave an idea about the type of bio-molecules which helped in the reduction of auric and silver salts into corresponding nano-particles. Anti-microbial activity of silver nano-particles showed that the nano-particles have better anti-microbial activity than 2% silver nitrate solution (kept as standard when experiments were performed under similar conditions. Conclusion: Gold and silver nano-particles were successfully synthesized using greener approach and anti-microbial activity of silver nano-particles prepared using aqueous neem extract was estimated against 2% AgNO3 solution. Nano-particles gave better anti-microbial activity than Silver nitrate solution.

  5. Synthesis and characterization of Gold and Silver nano-particles using different leaf extracts namely Catharanthus roseus, Datura metel and Azadirachta indica and Estimation of antimicrobial activity of silver nano-particles using disc diffusion method

    Sarbjeet Singh Gujral

    2014-01-01

    Objective: synthesis of gold and silver nano-particles using leaf extracts of Catharanthus roseus, Datura metel and Azadirachta indica and Estimation of antimicrobial activity of silver nano-particles using disc diffusion method. Method: Green approach has been utilized for the synthesis of gold and silver nano-particles. Different aqueous plant extracts has been prepared which was then utilized for the biosynthesis of gold and silver nano-particles. Estimation for the synthesis of nano-parti...

  6. Experimental Investigation of Bubble Dynamics in Nucleate Pool Boiling for TiO2 nano particle coated surface

    Enhancement of CHF of heater in the nano-fluid or nano-particle coated surface in the fresh water has been intensively studied. It was known that the wettability change and formation of the micro-porous structure on the nano-particle coated heater surface cause CHF enhancement. These changes on the heater surface will affect bubble departure dynamics but studies on the bubble dynamics on the nano-particle coated surface are rare. Therefore, the present study is performed to measure the bubble departure characteristics experimentally and to find one of reasons of CHF enhancement. Zuber correlated the multiplication of the bubble diameter and departure frequency as the drift velocity which appear again in his CHF correlation: fD = 0.092m/ s for the boiling water on the copper heater at atmospheric pressure. However, Ivey categorized three distinguished region based on the dominant physics: fD3/4 = 0.44 for the small bubbles from 0.2 to 0.5cm, fD1/2 = 0.90g1/2 for the mushroom like large bubble (D > 0.5cm) but for the thermal region fD2 = consant . All of these correlations are applicable to the bare heater on the fresh water not for the bare heater in the nano fluid or nano-particle coated heater in the fresh water. Therefore, in the present study, we measured bubble departure diameter and frequency for both bare surface heater and TiO2 nano-particle coated heater to explain partly why CHF of nano-particle coated surface is enhanced in term of macrolayer under the mushroom bubble

  7. Synthesis, in-situ dispersion and characterization of ZrO2 nano-particles coated with pentacene

    Full text: Stable suspensions of pentacene functionalized ZrO2 nano-particles were synthesized using a microwave plasma process. The particles were dispersed in-situ in ethylene glycol. The formation of coated particles with small cores and a well defined size in the range of 3-5 nm was shown by x-ray diffraction. In difference to resublimed pure pentacene, suspensions of the coated nano-particles remained stable for weeks, as confirmed by the observation of a small aggregate size in dynamic light scattering. (author)

  8. To see or not to see: Imaging surfactant coated nano-particles using HIM and SEM

    Nano-particles are of great interest in fundamental and applied research. However, their accurate visualization is often difficult and the interpretation of the obtained images can be complicated. We present a comparative scanning electron microscopy and helium ion microscopy study of cetyltrimethylammonium-bromide (CTAB) coated gold nano-rods. Using both methods we show how the gold core as well as the surrounding thin CTAB shell can selectively be visualized. This allows for a quantitative determination of the dimensions of the gold core or the CTAB shell. The obtained CTAB shell thickness of 1.0 nm–1.5 nm is in excellent agreement with earlier results using more demanding and reciprocal space techniques. - Author-Highlights: • CTAB coated gold nano-rods were imaged using high resolution imaging tools. • Selective imaging of either the gold core or CTAB shell is possible with HIM and SEM. • CTAB shell thickness measured using HIM and SEM agrees well with literature values

  9. Green synthesis, Characterization and anti microbial activity of silver nano particles –Review Paper

    Seeram. Hariprasad

    2015-10-01

    Full Text Available The exploitation of various plant materials for the biosynthesis of silver nano particles is considered a green technology. Because it does not involve any harmful chemicals. Nanotechnology field is one of the most attractive researches. The field of nanotechnology is applied to bio materials. This review focuses on the green synthesis of silver nanoparticles using various plant sources. A detailed study on the reduction of silver ions to silver nanoparticles from medical plant leaves extract were demonstrated with a brief experimental procedure. Characterization of the synthesized nanoparticles performed through UV spectroscopy, Fourier Transform Infra Red spectroscopy analysis, X-Ray Diffraction analysis, Scanning Electron Microscopy and Transmission Electron Microscopy. This review mainly focus on anti microbial activities of synthesized silver nano particles.

  10. Effects of nano-particles strengthening activating flux on the microstructures and mechanical properties of TIG welded AZ31 magnesium alloy joints

    Highlights: • Increased nano-particles strengthening activating flux degraded TIGed seams. • The reaction between SiC particles and Mg alloy produced Al4C3 and Mg2Si phases. • Al4C3 and SiC particles promoted the nucleation and suppressed the growth of α-Mg. • Refined α-Mg grains, precipitated phase and SiC particles enhanced TIGed joints. - Abstract: In this paper, AZ31 magnesium alloy joints were processed by nano-particles strengthening activating flux tungsten inert gas (NSA-TIG) welding, which was achieved by the mixed TiO2 and nano-SiC particles coated on the samples before welding tests. The macro/micro structural observation and mechanical properties evaluation of the welding joints were conducted by using optical microscope, scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction and tension and microhardness tests. The results showed that nano-particles strengthening activating flux effective improved the microstructure, microhardness in fusion zone, ultimate tensile strength of the TIG welding joints. In addition, the chemical reaction between part of SiC particles and AZ31 magnesium alloy produced Al4C3 and Mg2Si in the joints. The Al4C3 performed as nucleating agents for α-Mg and the dispersed Mg2Si and SiC particles enhanced the mechanical properties of the NSA-TIG welding joints. However, large heat input induced by the increase of the surface coating density of the nano-particles strengthening activating flux, increased the α-Mg grain sizes and weakened the mechanical properties of the welded joints. Therefore, the grain size of α-Mg, distribution of β-Mg17Al12, Mg2Si and SiC particles together influenced the evolution of the mechanical properties of the NSA-TIG welded AZ31 magnesium alloy joints

  11. Preparation of ZrC nano-particles reinforced amorphous carbon composite coating by atmospheric pressure chemical vapor deposition

    To eliminate cracks caused by thermal expansion mismatch between ZrC coating and carbon-carbon composites, a kind of ZrC/C composite coating was designed as an interlayer. The atmospheric pressure chemical vapor deposition was used as a method to achieve co-deposition of ZrC and C from ZrCl4-C3H6-H2-Ar source. Zirconium tetrachloride (ZrCl4) powder carrier was especially made to control accurately the flow rate. The microstructure of ZrC/C composite coating was studied using analytical techniques. ZrC/C coating shows same morphology as pyrolytic carbon. Transmission electron microscopy (TEM) shows ZrC grains with size of 10-50 nm embed in turbostratic carbon. The formation mechanism is that the growth of ZrC crystals was inhibited by surrounding pyrolytic carbon and kept as nano-particles. Fracture morphologies imply good combination between coating and substrate. The ZrC crystals have stoichiometric proportion near 1, with good crystalline but no clear preferred orientation while pyrolytic carbon is amorphous. The heating-up oxidation of ZrC/C coating shows 11.58 wt.% loss. It can be calculated that the coating consists of 74.04 wt.% ZrC and 25.96 wt.% pyrolytic carbon. The average density of the composite coating is 5.892 g/cm3 by Archimedes' principle.

  12. The Design and Simulated Performance of a Coated Nano-Particle Laser

    Gordon, J A; Gordon, Joshua A.; Ziolkowski, Richard W.

    2006-01-01

    The optical properties of a concentric nanometer-sized spherical shell comprised of an (active) 3-level gain medium core and a surrounding plasmonic metal shell are investigated. Current research in optical metamaterials has demonstrated that including lossless plasmonic materials to achieve a negative permittivity in a coated nano-sized spherical shell particle can lead to novel optical properties such as resonant scattering as well as transparency or invisibility. However, in practice, plasmonic materials have high losses at optical frequencies. It is observed that with the introduction of active materials, the intrinsic absorption in the plasmonic shell can be overcome and new optical properties can be observed in the scattering and absorption cross-sections of these coated nano-sized spherical shell particles. In addition, a "super" resonance is observed with a magnitude that is 10^3 greater than that for a tuned, resonant passive nano-sized coated spherical shell. This observation suggests the possibilit...

  13. Green synthesis, Characterization and anti microbial activity of silver nano particles –Review Paper

    Seeram. Hariprasad; Santhosh Kumar. J

    2015-01-01

    The exploitation of various plant materials for the biosynthesis of silver nano particles is considered a green technology. Because it does not involve any harmful chemicals. Nanotechnology field is one of the most attractive researches. The field of nanotechnology is applied to bio materials. This review focuses on the green synthesis of silver nanoparticles using various plant sources. A detailed study on the reduction of silver ions to silver nanoparticles from medical plant le...

  14. Gold nano-particles fixed on glass

    Highlights: ► We produced wear resistant gold–ruby coatings on amorphous substrates. ► Thin sputtered gold layers were covered by or embedded in silica coatings. ► Annealing above Tg of the substrate glass led to the formation of gold nano particles. ► A 1 1 1-texture of the gold particles is observed via XRD and EBSD. ► EBSD-patterns can be acquired from crystals covered by a thin layer of glass. - Abstract: A simple process for producing wear resistant gold nano-particle coatings on transparent substrates is proposed. Soda-lime-silica glasses were sputtered with gold and subsequently coated with SiO2 using a combustion chemical vapor deposition technique. Some samples were first coated with silica, sputtered with gold and then coated with a second layer of silica. The samples were annealed for 20 min at either 550 or 600 °C. This resulted in the formation of round, well separated gold nano-particles with sizes from 15 to 200 nm. The color of the coated glass was equivalent to that of gold–ruby glasses. Silica/gold/silica coatings annealed at 600 °C for 20 min were strongly adherent and scratch resistant. X-ray diffraction and electron backscatter diffraction (EBSD) were used to describe the crystal orientations of the embedded particles. The gold particles are preferably oriented with their (1 1 1) planes perpendicular to the surface.

  15. Nano-particles

    Nano-particles (N.P.) are structures comprising from some hundred to some thousand atoms. Owing to their size (1 to 100 nanometers), the physical and chemical properties of these nano-objects differ from those of classical materials. They cover a wide development area, which includes medical research: they can be classified into two major groups, organic N.P. (liposomes, polymers N.P., carbon nano tubes, fullerenes) and inorganic N.P. (quantum dots, magnetic N.P., Raman probes). N.P. can be conceived to act as a drug delivery system (therapeutic), imaging probe (diagnostic) or both (theranostic). We report recent data from scientific literature and describe main N.P. within medical area, their state of development, and the limited knowledge of their toxicity in human being. (author)

  16. First principles study of CO reactivity on metallic nano particles

    Lindberg, Vanja

    2007-01-01

    The activity of a surface is determined by the local electronic structure. When nano particles are adsorbed, the catalytic properties will change. Surfaces with adsorbed nano particles often show a significantly higher chemical reactivity than the clean counterpart. Gold, for instance, shows an extra high activity towards many reactions, such as low-temperature catalytic combustion, partial oxidation of hydrocarbons and CO oxidation when dispersed as ultra-fine particles on metal oxide surfac...

  17. Properties of Al2O3 nano-particle reinforced copper matrix composite coatings prepared by pulse and direct current electroplating

    Highlights: → The influence of Al2O3 is studied on morphologies of the DC and PC applied coatings. → The influence of Al2O3 is studied on the DC and PC coating thicknesses. → The influence of Al2O3 is studied on wear resistance. → The effect of Al2O3 is studied on the porosity and corrosion resistance. -- Abstract: Cu-Al2O3 nano-composite coatings have high potential for use in applications in which high mechanical properties together with high corrosion resistance are required. In the present study it is intended to produce copper nano-alumina composite coatings with various nano-alumina contents in order to investigate the effect of alumina reinforcement particles on corrosion resistance and mechanical properties such as hardness and wear resistance. The composite coatings were deposited using direct current (DC) and pulse current (PC) plating. The microstructures of the coatings produced from both methods were examined via scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The wear behaviors, micro hardness, coating thickness, corrosion rate and coating porosity were examined using appropriate methods. Compared to DC deposition, PC plating facilitated higher amounts of particle incorporation with more uniform distribution. The results indicated that the mechanical properties of the applied coatings with incorporated nano-alumina reinforcement were far more superior as compared to its own matrix as well as non-composite copper coatings. It was also found out that increasing the amount of nano-alumina content in the coating, led to enhanced general properties of the coatings.

  18. Study on the Mechanical Properties of Heat-Treated Electroless NiP Coatings Reinforced with Al2O3 Nano Particles

    Karthikeyan, S.; Vijayaraghavan, L.; Madhavan, S.; Almeida, A.

    2016-05-01

    This work reports the effects of electroless co-deposition of Al2O3 nanoparticles and NiP to obtain a NiP-Al2O3 coating on the structure and mechanical properties of the composite coatings. The effects of annealing heat treatments at 373 K, 473 K, 573 K, and 673 K (100 °C, 200 °C, 300 °C, and 400 °C) on the structure and properties of the coatings were evaluated. The as-deposited coatings are a mixture of crystalline and amorphous phases that tend to crystallize during heat treatment. Heat treatment at higher temperatures causes the precipitation of the Ni3P phase. The mechanical properties of as-deposited and heat-treated NiP-Al2O3 coatings were evaluated using depth-sensing indentation tests performed at loads of 200 mN. The incorporation of Al2O3 nanoparticles induces strengthening of the NiP coating by dispersion. Heat treatment of the NiP-Al2O3 coatings induced crystallization of the amorphous phase with the formation of nanosized grains and the precipitation of Ni3P. Consequently, there is an increase in the hardness and Young's modulus of the coatings to 15.4 ± 0.5 and 227 ± 2.8 GPa, respectively, in a combined hardening effect induced by dispersion of the Al2O3 nanoparticles and crystallization and precipitation during heat treatment.

  19. ADSORPTION OF NANO-PARTICLES ON BUBBLE SURFACE IN NANO-PARTICLE SUSPENSION

    Buxuan Wang; Chunhui Li; Xiaofeng Peng

    2005-01-01

    The adsorption of nano-particles on bubble surface is discussed for saturated boiling on thin wire of nano-particle suspensions. Owing to the decrease of surface tension for suspensions, the nano-particles tend to adsorb on the bubble surface to decrease the Gibbs free energy for stability, and meanwhile the velocity of nano-particles would be smaller than that of bubble growth. The long-range van der Waals force existing between "water particles" and nano-particles is considered the attractive force between the nano-particles and the bubble surface. Thus, the nano-particles would attach on the bubble surface if the particle-surface distance is smaller than its critical value. The distribution of nano-particles on the bubble surface and in the adjacent region is also investigated.

  20. Nano-particles;Les nanoparticules

    Chuto, G. [Institut Paoli-Calmettes, Service de medecine nucleaire, 13 - Marseille (France); Chaumet-Riffaud, P. [CHU de Bicetre, Service de medecine nucleaire, 94 - Le Kremlin Bicetre (France)

    2010-06-15

    Nano-particles (N.P.) are structures comprising from some hundred to some thousand atoms. Owing to their size (1 to 100 nanometers), the physical and chemical properties of these nano-objects differ from those of classical materials. They cover a wide development area, which includes medical research: they can be classified into two major groups, organic N.P. (liposomes, polymers N.P., carbon nano tubes, fullerenes) and inorganic N.P. (quantum dots, magnetic N.P., Raman probes). N.P. can be conceived to act as a drug delivery system (therapeutic), imaging probe (diagnostic) or both (theranostic). We report recent data from scientific literature and describe main N.P. within medical area, their state of development, and the limited knowledge of their toxicity in human being. (author)

  1. Optimizing critical heat flux enhancement through nano-particle-based surface modifications

    Colloidal dispersions of nano-particles, also known as nano-fluids, have shown to yield significant Critical Heat Flux (CHF) enhancement. The CHF enhancement mechanism in nano-fluids is due to the buildup of a porous layer of nano-particles upon boiling. Unlike microporous coatings that had been studied extensively, nano-particles have the advantages of forming a thin layer on the substrate with surface roughness ranges from the sub-micron to several microns. By tuning the chemical properties it is possible to coat the nano-particles in colloidal dispersions onto the desired surface, as has been demonstrated in engineering thin film industry. Building on recent work conducted at MIT, this paper illustrates the maximum CHF enhancement that can be achieved based on existing correlations. Optimization of the CHF enhancement by incorporation of key factors, such as the surface wettability and roughness, will also be discussed. (authors)

  2. Silicon nano-particles: on Route to a Sustainable Mobility

    Munao, D.

    2012-01-01

    The area of nanotechnology is one of the most active fields in science today. It is often seen as the area that could lead to substantial progress in terms of finding new materials with new properties. In this respect, silicon nano-particles are found to be greatly attractive because of their signif

  3. Silicon nano-particles: on Route to a Sustainable Mobility

    Munao, D.

    2012-01-01

    The area of nanotechnology is one of the most active fields in science today. It is often seen as the area that could lead to substantial progress in terms of finding new materials with new properties. In this respect, silicon nano-particles are found to be greatly attractive because of their significant technological implications. Considering different areas of research, the energy production, conversion and storage processes are definitely among the most important topics to be studied by sc...

  4. Stable Poly(methacrylic acid Brush Decorated Silica Nano-Particles by ARGET ATRP for Bioconjugation

    Marcello Iacono

    2015-08-01

    Full Text Available The synthesis of polymer brush decorated silica nano-particles is demonstrated by activator regeneration by electron transfer atom transfer radical polymerization (ARGET ATRP grafting of poly(tert-butyl methacrylate. ATRP initiator decorated silica nano-particles were obtained using a novel trimethylsiloxane derivatised ATRP initiator obtained by click chemistry. Comparison of de-grafted polymers with polymer obtained from a sacrificial initiator demonstrated good agreement up to 55% monomer conversion. Subsequent mild deprotection of the tert-butyl ester groups using phosphoric acid yielded highly colloidal and pH stable hydrophilic nano-particles comprising approximately 50% methacrylic acid groups. The successful bio-conjugation was achieved by immobilization of Horseradish Peroxidase to the polymer brush decorated nano-particles and the enzyme activity demonstrated in a conversion of o-phenylene diamine dihydrochloride assay.

  5. Synthesis and characterization of struvite nano particles

    Rathod, K. R.; Jogiya, B. V.; Chauhan, C. K.; Joshi, M. J.

    2015-06-01

    Struvite, Ammonium Magnesium Phosphate Hexahydrate [(AMPH) - (NH4)MgPO4.6(H2O)], is one of the fascinating inorganic phosphate minerals. Struvite is one of the components of the urinary stones. Struvite occurs as crystallites in urine and grows as a type of kidney stone. In this study, struvite nano particles were synthesized by wet chemical technique. The aqueous solutions containing dissolved Mg(CH3COO)2.4H2O and (NH4)H2PO4 mixed at the Mg/P molar ratio of 1.00. The synthesized struvite nano particles were characterized by XRD, FT-IR, Thermal Analysis and TEM. From XRD, crystal structure of the nano particle was found to be orthorhombic and crystalline size was found to be within 11 to 26 nm. The FT-IR spectrum for the struvite nano particles confirmed the presence of a water molecule and metal-oxygen stretching vibration, O-H stretching and bending, N-H bending and stretching, P-O bending and stretching vibrations. The Thermal Analysis was carried out from room temperature to 900°C. From TEM analysis, particle size was 23 to 30 nm. All the results were compared with bulk struvite.

  6. Optimization of surface coating condition using vapor form of alkanethiol on Cu nano powders for the application of oxidation prevention

    There has been a growing interest in metal nano powders recently, and researches on Copper (Cu) nano particles are actively pursued due to its good electrical conductivity and its low prices. However, its easiness to oxidation and corrosion has delayed its research progress in Cu nano particles to be applied in inkjet printed electronics and other related research area. To overcome these problems, new surface coating method on Cu nano particles has been developed using dry process instead of conventional wet coating method. Octanethiol was used as a dry coating material because it has sulfur at the end of monolayer to chemically bond to the surface of fresh non-oxidized Cu nano particles to prevent oxidation. Octanethiol does not bond to oxidized surface of Cu nano particles. Previously, bonding between octanethiol and Cu nano particles, more specifically bonding between Cu surface and Sulfur (S) was analyzed using X-ray Photoelectron Spectroscopy (XPS). As a result, S peak was detected on the coated Cu nano particles, indicating that octanethiol chain has been successfully coated on the surface of Cu nano particles. In this study, optimization of dry coating condition was studied by varying coating time and cycles. XPS was used to analyze the composition of coated material to monitor the change in amount of S and O peaks for each condition. It was found that as the amount of Sulfur increased, the amount of Oxygen decreased and vice versa. This finding indicates that dry coating has suppressed the formation of oxygen on the surface of Cu nano powders by surrounding Cu surface with Sulfur end of octanethiol chain. Based on these experiments, the optimum coating condition for suppressing Cu oxidation was found to be 5 min and 6 cycles. For future work, the lifetime of octanethiol layer on the surface of Cu surface needs to be studied.

  7. Infrared and Raman spectroscopic studies on iron oxide magnetic nano-particles and their surface modifications

    Iron oxide magnetic nano-particles (MNPs) have been prepared in aqueous solution by a modified co-precipitation method. Surface modifications have been carried out using tetraethoxysilane (TEOS), triethoxysilane (TES) and 3-aminopropyltrimethoxysilane (APTMS). The uncoated and coated particle products have been characterized with transmission electron microscope (TEM), energy dispersive X-ray (EDX) spectroscopy, infrared (IR) and Raman spectroscopy, and thermal gravimetric analysis (TGA). The particle sizes were determined from TEM images and found to have mean diameters of 13, 16 and 14 nm for Fe3O4, TES/Fe3O4 and APTMS/Fe3O4, respectively. IR and Raman spectroscopy has been applied to study the effect of thermal annealing on the uncoated and coated particles. The results have shown that magnetite nano-particles are converted to maghemite at 109 °C and then to hematite by 500 °C. In contrast, the study of the effect of thermal annealing of micro-crystalline magnetite by IR spectroscopy revealed that the conversion to hematite began by 300 °C and that no maghemite could be identified as an intermediate phase. IR spectra and TGA measurements revealed that the Si–H and 3-aminopropyl functional groups in TES and APTMS coated magnetite nano-particles decomposed below 500 °C while the silica layer around the iron oxide core remained unchanged. The molecular ratio of APTMS coating to iron oxide core was determined to be 1:7 from the TGA data. Raman scattering signals have indicated that MNPs could be converted to maghemite and then to hematite using increasing power of laser irradiation in a manner similar to that observed for thermal annealing. - Highlights: ► A modified co-precipitation method to prepare dispersive iron oxide magnetic nano-particles. ► Coating the nano-particle with different silicas. ► Estimating the numbers of iron oxide and 3-aminopropylsilica in the coated particles. ► Silica coating may help to protect iron oxide nano-particles from

  8. Subcooled boiling of nano-particle suspensions on Pt wires

    LI Chunhui; WANG Buxuan; PENG Xiaofeng

    2004-01-01

    An experimental investigation is conducted to explore the subcooled boiling characteristics of nano-particle suspensions on Pt wires. Some phenomena are observed for the boiling of water-SiO2 nano-particle suspensions on Pt wires. The experiments show that there exist not any evident differences for boiling of pure water and of nano-particle suspensions at high heat fluxes. However, bubble overlap phenomenon can be easily found for nano-particle suspensions at low heat fluxes, which probably results from the increase of the attracter force between bubbles and of the bubble mass.

  9. Effect of gold nano-particle layers on ablative acceleration of plastic foil targets

    Dhareshwar, L.J.; Gupta, N.K.; Chaurasia, S.; Ayyub, P.; Kulkarni, N.; Badziak, J.; Pisarczyk, T.; Kasperczuk, A.; Parys, P.; Rosinski, M.; Wolowski, J.; Krouský, Eduard; Krása, Josef; Mašek, Karel; Pfeifer, Miroslav; Skála, Jiří; Ullschmied, Jiří; Velyhan, Andriy; Margarone, Daniele; Mezzasalma, A.; Pisarczyk, P.

    2010-01-01

    Roč. 244, č. 2 (2010), 022018/1-022018/8. ISSN 1742-6588 R&D Projects: GA MŠk(CZ) LC528; GA MŠk(CZ) 7E08094 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z20430508 Keywords : laser pulse absorption * nano-particle coating * lateral thermal conduction Subject RIV: BL - Plasma and Gas Discharge Physics

  10. Spectroscopic characterization of the effect of gamma radiation on the physical parameters of biosynthesized silver/chitosan nano-particles and their antimicrobial activity

    Osman, Mohamed E.; Eid, May M.; Khattab, Om kolthoum H.; El-Hallouty, Salwa M.; El-Marakby, Seham M.; Mahmoud, Doaa A.

    2015-09-01

    Studying the effect of pH on the biosynthesis of silver/chitosan nanoparticles (Ag/CS NPs) using Aspergillus deflectus and Penicillium pinophilum as reducing agents, showed very weak surface plasmon resonance (SPR) of Ag/CS NPs at certain pH. In this paper, the effect of irradiation on the synthesis of Ag/CS at non-optimum pH was evaluated and thereby, the antimicrobial effect of the biosynthesized Ag/CS NPs. The SPR of the AgNPs was analyzed by UV-visible spectroscopy. The active groups responsible for the reduction and capping of the AgNPs were analyzed by Fourier transform infrared (FTIR), and their shape and size were determined via high resolution transmission electron microscopy (HRTEM) and the dynamic light scattering (DLS) technique. UV/Visible spectroscopy confirmed the appearance of AgNPs’ SPR. Additionally, the FTIR spectroscopy confirmed the Ag/CS NP formation. Data also revealed that increasing both the pH and irradiation dose resulted in a decrease of the Ag/CS NPs’ size. DLS and HRTEM results showed that the best pH for biosynthesis of Ag/Cs is 7.5 at 50 kGy considering the particle size and crystallinity. Also, pH 8.5 gave the best antimicrobial activity of the Ag/CS NPs from Penicillium against both S. aureus and E. coli, while 8.5 and 7.5 were the best in the same order, for Ag/CS from Aspergillus.

  11. 纳米SiO_2改性输电铁塔防腐蚀涂料%Transmission Tower Anti-corrosion Coatings Modified by SiO2 Nano-particles

    刘江; 谢凤龙; 陈颖敏; 俞立

    2012-01-01

    The agglomeration of nano-SiO2 particles was improved by ultrasonic dispersion and adding dispersing agents to protect the newborn nano-particles.The dispersed nano-SiO2 particles can improve the fluorocarbon finish property.The experimental results indicate that the best time of ultrasonic dispersion was about 30 minutes,and KH570,CH hyper-dispersant and BYK-163 were selected as dispering agents,the performance of KH570 was the best.Both the mechanical properties and the ability to resist chemical reagent of modified fluorocarbon finish were improved and could meet the national standard.%采用超声分散纳米SiO2,同时添加分散剂保护新生纳米SiO2粒子,在一定程度上改善了纳米SiO2团聚的现象,并将分散好的纳米SiO2加入氟碳面漆,用以改性氟碳面漆的性能。选用硅烷偶联剂KH570、CH超分散剂、BYK-163三种分散剂。结果表明,超声分散时间为30min左右,硅烷偶联剂KH570分散纳米SiO2的效果最好;纳米SiO2改性后的氟碳面漆,机械性能与耐化学试剂性能均有了较大改善,各项性能均达到国家标准。

  12. Synthesis of nano-composite surfaces via the co-deposition of metallic salts and nano particles

    Highlights: • Nanofaceted surfaces are prepared by a low current density (2) electrodeposition method. • Surfaces are formed of nanoparticles anchored to a conductive (carbon) substrate. • Formed surfaces show a high nano-reactivity and surface area. • Demonstration of INP/FeCl3 nanocomposite for water filtration effectively removing BTEX contamination. -- Abstract: A novel, low energy method for coating different nano-particles via electro-deposition to a recyclable carbon glass supporting structure is demonstrated. In the resulting composite, the nano-material is bound to the substrate surface, thereby removing the potential for causing harmful interactions with the environment. Nano-particles were suspended in a salt solution and deposited at low current densities (−2) producing thin (<100 nm), uniform nano-faceted surfaces. A co-deposition mechanism of nano-particles and cations from the salt solution is proposed and explored. This has been successfully demonstrated for iron, sliver, titanium in the current work. Furthermore, the removal of the surface coatings can be achieved via a reversed current applied over the system, allowing for the recovery of surface bound metal contaminants. The demonstrated applicability of this coating method to different nano-particle types, is useful in many areas within the catalysis and water treatment industries. One such example, is demonstrated, for the treatment of BTEX contamination and show a greatly improved efficiency to current leading remediation agents

  13. Adsorption of nuclease p1 on chitosan nano-particles

    Lu-E Shi

    2009-06-01

    Full Text Available The sorption of nuclease P1 onto chitosan nano-particles is studied in this paper. The effect of some adsorption kinetics factors such as nuclease P1 concentration, chitosan nano-particles solution concentration, adsorption temperature, chitosan nano-particles size, solution pH, etc. is investigated. Adsorption of nuclease P1 onto chitosan nano-particles is fitted into Lagergren first-order equation at initial nuclease P1 concentration of 3.0 mg/mL. The first-order constant for nuclease P1 is 22.98 h-1. When nuclease P1 concentration is controlled into certain region, the adsorption fits into Freundlich isothermal linear equation. A mechanism of adsorption for nuclease P1 is proposed by analyzing IR spectra. The IR spectra shows that the hydrogen bond might be the main force between the hydroxyl group, the NH2 group and the nuclease P1.

  14. Role of plant growth promoting rhizobacteria and Ag-nano particle in the bioremediation of heavy metals and maize growth under municipal wastewater irrigation.

    Khan, Naeem; Bano, Asghari

    2016-01-01

    The investigation evaluated the role of plant growth promoting rhizobacteria (PGPR) and Ag-nano particle on the growth and metabolism of maize irrigated with municipal wastewater (MW). Three PGPR isolated from MW were identified on the basis of 16S-rRNA gene sequence analyses as Pseudomonas sp., Pseudomonas fluorescence, and Bacillus cereus. The municipal waste water was used to irrigate the maize seeds inoculated with 3 isolated PGPR. The isolated PGPR had catalase and oxidase enzymes, solubilize insoluble bound phosphate and exhibit antifungal and antibacterial activities. The colony forming unit (cfu) of the PGPR was inhibited by Ag-nano particle, but was stimulated by the municipal wastewater. The Ag-nano particles augmented the PGPR induced increase in root area and root length. The root-shoot ratio was also changed with the Ag-nano particles. The plants irrigated with municipal wastewater had higher activities of peroxidase and catalase which were further augmented by Ag-nano particle. The Ag- nano particle application modulated level of ABA (34%), IAA (55%), and GA (82%), increased proline production (70%) and encountered oxidative stress and augmented the bioremediation potential of PGPR for Pb, Cd, and Ni. Municipal wastewater needs to be treated with PGPR and Ag nano particle prior to be used for irrigation. This aims for the better growth of the plant and enhanced bioremediation of toxic heavy metals. PMID:26507686

  15. The anomalous physical and chemical properties of gold nano-particles

    Full text: Although gold is the most inert of all metallic elements, it has been discovered during the last two decades that it has interesting properties as a nano-particle. Some of the properties of interest include its activity as a heterogeneous catalyst, particularly at low temperatures, its optical properties, and the tendency of its nano-particles to adopt non-crystallographic structures. There are a number of curious aspects to catalysis by gold that are attracting academic and industrial investigation and much is still not understood about the mechanism by which they work. For example, apparently similar preparation techniques result in activities of hugely varying magnitude. In the present talk I assess the what is known about gold nano-particles, with particular reference to their physical, electronic, crystallographic and catalytic properties. It is shown that there is much evidence in favour of the belief that it is the unique electronic structure of these particles that imbues them with catalytic activity. If this is true then tighter control of the electronic structure would allow for the design of more specific and more active catalysts

  16. Nano particles@Calix arenas via aqueous solution

    Sahar Dehghani

    2016-05-01

    Full Text Available The electronic structure and magnetic properties of Al2O3, GaN and Fe3O4@ Calix (8 COOH have been studied using ONIOM and DFT methods. The studies focus on how to improve the adsorption of some nano particles solution aqueous for achieving good magnetic and functionalized potential performances. The results revealed that the Fe3O4@ Calix (8 COOH and some of its derivations exhibited better thermodynamic stability. Furthermore, the particle size and magnetic property of the GaN@ Calix (8 COOH nano particles can be controlled by the aqueous. The electrical properties such as NMR Shielding, electron densities, energy densities, potential energy densities, ELF, LOL, ellipticity of electron density, eta index and ECP for nano particles@ Calix (8COOH have been calculated.

  17. Thermal performance of heat pipe with suspended nano-particles

    Shukla, K.N. [Gurgaon College of Engineering, Gurgaon (India); Solomon, A.B.; Pillai, B.C.; Ruba Singh, B.J.; Saravana Kumar, S. [Karunya University, Centre for Research in Thermal Management, Coimbatore (India)

    2012-11-15

    Nanofluids are employed as the working medium for a conventional cylindrical heat pipe. A cylindrical copper heat pipe of 19.5 mm outer diameter and 400 mm length was fabricated and tested with two different working fluids. The working fluids used in this study are DI-water and Nano-particles suspension (mixture of copper nano particle and DI-water). The overall heat transfer coefficient of the heat pipe was calculated based on the lumped thermal resistance network and compared with the heat transfer coefficient of base fluid filled heat pipe. There is a quantitative improvement in the heat transfer coefficient using nano-particles suspension as the working medium. A heat transfer correlation was also developed based on multiple regression least square method and the results were compared with that obtained by the experiment. (orig.)

  18. Thermal performance of heat pipe with suspended nano-particles

    Shukla, K. N.; Solomon, A. Brusly; Pillai, B. C.; Ruba Singh, B. Jacob; Saravana Kumar, S.

    2012-11-01

    Nanofluids are employed as the working medium for a conventional cylindrical heat pipe. A cylindrical copper heat pipe of 19.5 mm outer diameter and 400 mm length was fabricated and tested with two different working fluids. The working fluids used in this study are DI-water and Nano-particles suspension (mixture of copper nano particle and DI-water). The overall heat transfer coefficient of the heat pipe was calculated based on the lumped thermal resistance network and compared with the heat transfer coefficient of base fluid filled heat pipe. There is a quantitative improvement in the heat transfer coefficient using nano-particles suspension as the working medium. A heat transfer correlation was also developed based on multiple regression least square method and the results were compared with that obtained by the experiment.

  19. Neuroprotective effect of curcumin-loaded lactoferrin nano particles against rotenone induced neurotoxicity.

    Bollimpelli, V Satish; Kumar, Prashant; Kumari, Sonali; Kondapi, Anand K

    2016-05-01

    Curcumin is known to have neuroprotective role and possess antioxidant, anti-inflammatory activities. Rotenone, a flavonoid induced neurotoxicity in dopaminergic cells is being widely studied in Parkinson's Disease (PD) research. In the present study, curcumin loaded lactoferrin nano particles prepared by sol-oil chemistry were used to protect dopaminergic cell line SK-N-SH against rotenone induced neurotoxicity. These curcumin loaded nano particles were of 43-60 nm diameter size and around 100 nm hydrodynamic size as assessed by transmission electron microscopy, atomic force microscopy and dynamic light scattering analysis respectively. The encapsulation efficiency was 61.3% ± 2.4%. Cellular uptake of curcumin through these nano particles was confirmed by confocal imaging and spectrofluorimetric analysis. The curcumin loaded lactoferrin nanoparticles showed greater intracellular drug uptake, sustained retention and greater neuroprotection than soluble counterpart. Neuroprotective activity was characterized through viability assays and by estimating ROS levels. Furthermore rotenone induced PD like features were characterized by decrease in tyrosine hydroxylase expression and increase in α-synuclein expression. Taken together curcumin loaded lactoferrin nanoparticles could be a promising drug delivery strategy against neurotoxicity in dopaminergic neurons. PMID:26826319

  20. Level Statistics and Specific Heat of Metallic Nano-Particles

    程南璞; 陈志谦; 陈洪

    2003-01-01

    The thermodynamic properties of an ensemble of metallic nano-particles are affected by the level distribution and the level correlation between the discrete electronic energy levels. We numerically calculate the specific heat of metallic nano-particles in the canonical ensemble with an odd or even number of electrons by considering the effects of the level distribution and the level correlation. The behaviour of the specific heat at low and high temperatures, compared with the average nearest-neighbour level spacing, is also investigated.

  1. Femtosecond dynamics of electronic populations in silver nano-particles

    This work deals with the dynamic of relaxation of hot electrons in silver nano-particles in a transparency matrix. Using laser impulses of a few hundred femtosecond, out equilibrium electronic populations are created and their relaxation is studied by the energy transfer to the crystalline network. The size and the geometry of these nano-particles lead to great optical non-linearities and electric confinement effects. This confinement leads then to a collective mode, named surface plasmon. Thanks to its structure, the silver owns a surface plasmon resonance far from the interband transitions, which allows the study of this collective mode. Differential measures, in degenerated pump-probe configuration and on silver nano-particles, show a slowing of the dynamic at the surface plasmon resonance. In a non degenerated pump-probe configuration, the differential transmission spectra show an asymmetrical first derivative behavior of the absorption ray. The author shows also that the relaxation dynamics depends of the nano-particles size and of the host matrix. (A.L.B.)

  2. Ni-Pd纳米涂层整体式催化剂加氢性能研究%Study of Hydrogenation Performance for Ni-Pd Monolithic Catalyst with Nano-particle Washcoat

    侯宁; 付瑶; 朱秋锋; 文利雄; 陈建峰

    2011-01-01

    A novel cordierite monolithic catalyst with porous hollow silica nano-particles as washcoat was prepared by a dip-coating method and the Pd active component and Ni promoter were loaded by a microwave method. The performance of the prepared catalysts for selective hydrogenation of acetylene was investigated at varying space velocity, the porous hollow silica nano-particles coating amount and Ni loading amount It was found that the coating of porous hollow silica nano-particles on the cordierite substrate could significantly promote the catalytic performance. When the space velocity was 3 800 h1, the mass fraction of coating on porous hollow silica nano-particles was 6%, the molar ratio of Ni and Pd was 4 I 1, the reaction pressure was 0.1 Mpa and reaction temperature was 54 t, theethylene selectivity of the novel catalyst still remained 40.9% when theacetylene was nearly completely converted.%采用浸涂法将自制的介孔空心Si02纳米粉体涂覆到堇青石基体上,然后采用微波法负载活性组分Pd和助剂 Ni制备了纳米涂层整体式加氢催化剂,并考察空速、涂层增重、Ni助剂添加量等因素对其乙炔选择性加氢催化性能的影响.结果表明:经过涂覆后的堇青石整体式催化剂加氢性能与未涂覆时相比有了显著提高,且添加适量的助剂Ni有助于催化性能的进一步改进.在反应温度为54℃、压力为0.1 MPa、空速为3 800h-1的条件下,使用涂层增量质量分数为6%、Ni与Pd物质的量比为4:1的催化剂,当乙炔接近完全转化时,乙烯选择性能够到达40.9%.

  3. Synthesis and spectroscopic investigations of iron oxide nano-particles for biomedical applications in the treatment of cancer cells

    Atta, Aly H.; El-ghamry, Mosad A.; Hamzaoui, Adel; Refat, Moamen S.

    2015-04-01

    Recently, upon the great importance of synthesized nano-particles especially ferric oxides on medicinal applications, these nano-particles have been prepared here using friendly and low cost biological precursors moieties via a thermal decomposition method. The Fe2O3 nano-particles preparation method is based on thermal degradation of ferric complexes of hippuric acid, itaconic acid, or tyrosine amino acid at 600 °C. The used precursors were characterized by several characterization techniques such as microanalysis, conductance, infrared spectra, electronic spectra, and thermogravimetric (TG/DTG). The calcinations stages were identified from the thermogravimetric analyses of ferric complexes. The narrow size distribution in nano-scale range for the Fe2O3 crystals have been studied using X-ray powder diffraction (XRD), scanning electron microscope (SEM), X-ray energy dispersive spectrometer (EDX) and transmission electron microscopy (TEM) analyzer. XRD data indicate that a single phase Fe2O3 nano-particles are obtained with particle size ranging from 20 to 60 nm. The cytotoxic activity of the Fe2O3 nanoparticles was tested against the breast carcinoma cells (MCF-7 cell line). The results of inhibitory concentration fifty (IC50) were existed within the 3.10-3.81 μg limit.

  4. Ion induced transformation of polymer films into diamond-like carbon incorporating silver nano particles

    Silver containing diamond-like carbon (DLC) is an interesting material for medical engineering from several points of view. On the one hand DLC provides high mechanical robustness. It can be used as biocompatible and wear resistant coating for joint replacing implants. On the other hand silver has antimicrobial properties, which could reduce post-operative inflammations. However conventional production of Ag-DLC by co-deposition of silver and carbon in a plasma process is problematic since it does not allow for a separate control of nano particle morphology and matrix properties. In this work an alternative production method has been developed to circumvent this problem. In metall-DLC-production by ion implantation into a nano composite, silver nano particles are initially formed in solution and then incorporated within a polymer matrix. Finally the polymer is transformed into DLC by ion implantation. The aspects and single steps of this method were investigated with regard to the resulting material's properties. The goal was to design an economically relevant deposition method. Based on experimental results a model of the transformation process has been established, which has also been implemented in a computer simulation. Finally the antibacterial properties of the material have been checked in a biomedical test. Here a bacterial killing rate of 90% could be achieved. (orig.)

  5. First Synthesis of Uranyl Aluminate nano-particles

    This paper describes, for the first time, a simple method for the synthesis of uranyl aluminate (URAL) nano-particles. URAL was prepared by U(VI) hydrolytic precipitation with ammonia at pH = 11 in the presence of meso-porous alumina MSU-X under 20 kHz of sonication followed by annealing of the obtained solids at 800 C. TEM, XAFS, powder XRD, and 27Al MAS NMR studies revealed that the speciation of uranium in this system strongly depends on uranium concentration. The sample with 5 wt % of uranium yields air-stable nano-particles (similar to 5 nm) of URAL. Presumably, UO22+ cations in this compound are coordinated with bidentate AlO2- groups. The increase of uranium concentration to 30 wt % causes mostly formation of U3O8 fine particles (similar to 50 nm) and small amounts of URAL. (authors)

  6. First Synthesis of Uranyl Aluminate nano-particles

    Chave, T.; Nikitenko, S. I. [UMII, ICSM, CEA, CNRS, ENSCM, Ctr Marcoule, UMR 5257, F-30207 Bagnols Sur Ceze (France); Scheinost, A. C. [European Synchrotron Radiat Facil, Rossendorf Beamline CRG BM20, F-38043 Grenoble (France); Scheinost, A. C. [FZD, Inst Radiochem, D-01314 Dresden (Germany); Berthon, C.; Arab-Chapelet, B.; Moisy, Ph. [CEA Marcoule, DEN, DRCP, Ctr Marcoule, F-30207 Bagnols Sur Ceze (France)

    2010-07-01

    This paper describes, for the first time, a simple method for the synthesis of uranyl aluminate (URAL) nano-particles. URAL was prepared by U(VI) hydrolytic precipitation with ammonia at pH = 11 in the presence of meso-porous alumina MSU-X under 20 kHz of sonication followed by annealing of the obtained solids at 800 C. TEM, XAFS, powder XRD, and {sup 27}Al MAS NMR studies revealed that the speciation of uranium in this system strongly depends on uranium concentration. The sample with 5 wt % of uranium yields air-stable nano-particles (similar to 5 nm) of URAL. Presumably, UO{sub 2}{sup 2+} cations in this compound are coordinated with bidentate AlO{sub 2}{sup -} groups. The increase of uranium concentration to 30 wt % causes mostly formation of U{sub 3}O{sub 8} fine particles (similar to 50 nm) and small amounts of URAL. (authors)

  7. Making PMMA, PMA, PVAc and PSt nano particles using radiation

    Full text: During the last decade considerable research effort has been directed to making very small (10-50 nm diam.) nano size polymer particles. Most of the techniques described used more than one surfactant at high concentrations and resulted in relatively low polymer concentration. We have developed methods to make nano size polymer particles from methyl methacrylate (MMA), methyl acrylate (MA), vinyl acetat (Vac) and styrene (St) with a single anionic surfactant and gamma radiation. We succeeded in making nano particles in up to 15% concentration and with much higher polymer/ surfactant ratio than the earlier methods. With the radiation technique we can obtain high yield of polymer and can control the particle size of the polymer in the 2S208) instead of gamma irradiation. At present we prefer gamma initiation, because we have much better control and reproducibility of the exothermic polymerisation reaction, hence the critical parameters can be evaluated more accurately. We have started to use the different nano particles prepared for adsorption studies, as seeds for polymerisation and for making transparent gels with nano structure. We are also looking for other applications of the nano particles. It should be noted that the surface area of 1 gram of 20 nm diameter spheres is 300m2

  8. Deposition of Flame-generated Al2O3 Nano-particles on a Porous Surface

    Andersen, Sune Klint; Johannessen, Jens Tue; Wedel, Stig;

    1998-01-01

    When particles of catalytic materials become less than 50 nm they start toexhibit a stronger catalytic activity compared to their bulk counterparts. Nano-particles are thus good candidates for manufacture of highly activecatalysts. Nanometer sized particles of catalytic materials may be generated...... athigh temperatures in flames. The direct deposition from gas phase on a ceramicsubstrate tube of flame-generated particles leads to a uniform, porous layer ofsmall particles, masking the coarser structure of the substrate tube. The methodlooks promising for manufacture of catalytic filters and membranes....

  9. Active coatings technologies for tailorable military coating systems

    Zunino, J. L., III

    2007-04-01

    The main objective of the U.S. Army's Active Coatings Technologies Program is to develop technologies that can be used in combination to tailor coatings for utilization on Army Materiel. The Active Coatings Technologies Program, ACT, is divided into several thrusts, including the Smart Coatings Materiel Program, Munitions Coatings Technologies, Active Sensor packages, Systems Health Monitoring, Novel Technology Development, as well as other advanced technologies. The goal of the ACT Program is to conduct research leading to the development of multiple coatings systems for use on various military platforms, incorporating unique properties such as self repair, selective removal, corrosion resistance, sensing, ability to modify coatings' physical properties, colorizing, and alerting logistics staff when tanks or weaponry require more extensive repair. A partnership between the U.S. Army Corrosion Office at Picatinny Arsenal, NJ along with researchers at the New Jersey Institute of Technology, NJ, Clemson University, SC, University of New Hampshire, NH, and University of Massachusetts (Lowell), MA, are developing the next generation of Smart Coatings Materiel via novel technologies such as nanotechnology, Micro-electromechanical Systems (MEMS), meta-materials, flexible electronics, electrochromics, electroluminescence, etc. This paper will provide the reader with an overview of the Active Coatings Technologies Program, including an update of the on-going Smart Coatings Materiel Program, its progress thus far, description of the prototype Smart Coatings Systems and research tasks as well as future nanotechnology concepts, and applications for the Department of Defense.

  10. Nano particles@Calix arenas via aqueous solution

    Sahar Dehghani

    2016-01-01

    The electronic structure and magnetic properties of Al2O3, GaN and Fe3O4@ Calix (8) COOH have been studied using ONIOM and DFT methods. The studies focus on how to improve the adsorption of some nano particles solution aqueous for achieving good magnetic and functionalized potential performances. The results revealed that the Fe3O4@ Calix (8) COOH and some of its derivations exhibited better thermodynamic stability. Furthermore, the particle size and magnetic property of the GaN@ Calix (8) C...

  11. Rapid laser sintering of metal nano-particles inks

    Ermak, Oleg; Zenou, Michael; Bernstein Toker, Gil; Ankri, Jonathan; Shacham-Diamand, Yosi; Kotler, Zvi

    2016-09-01

    Fast sintering is of importance in additive metallization processes and especially on sensitive substrates. This work explores the mechanisms which set limits to the laser sintering rate of metal nano-particle inks. A comparison of sintering behavior of three different ink compositions with laser exposure times from micro-seconds to seconds reveals the dominant factor to be the organic content (OC) in the ink. With a low OC silver ink, of 2% only, sintering time falls below 100 μs with resistivity <×4 bulk silver. Still shorter exposure times result in line delamination and deformation with a similar outcome when the OC is increased.

  12. Bio-hydrogen: immobilization of enzymes on electrodes modified by clayey nano-particles

    In this work, has been studied the immobilization of enzymes inside micro-films constituted of clayey nano-particles and layer by layer nano-assembling of clayey nano-particles and enzyme. Natural clays have very great specific surface areas, very strong ions exchange capacities and a swelling lamellar structure particularly well adapted to the non denaturing adsorption of proteins and charged enzymes. In this study, the enzymes have been extracted of sulfate-reducing bacteria. The immobilization of this system in clayey films has been studied by micro-gravimetry/electrochemistry coupling and the catalytic activity towards the production and the consumption of hydrogen quantified. At first, the clay is deposited in layer of thickness of the micron on the gold or graphite electrode. When the hydrogenase is immobilized in the clayey film, the electro-enzymatic oxidation of hydrogen occurs inside the clayey structure. An electrode able to measure either the hydrogen consumption or its production on a wide pH range as thus been prepared, by co-immobilization of hydrogenase and of MV2+ in montmorillonite films. The catalytic efficiencies obtained by immobilization in the clayey matrix of the two physiological partners, cytochrome c3 and hydrogenase, are strongly improved. Then, this process has been still improved, and three cytochrome c3/clay bilayers have been superposed without loss of the enzymatic activity. (O.M.)

  13. A NOVEL SEPARATION TECHNOLOGY FOR NANO PARTICLES AT DISCHARGE OF COMBUSTION AND INCINERATION EQUIPMENT

    Daniele Accornero

    2012-07-01

    Full Text Available Still today, the issue of safely and efficiently avoiding the atmospheric release of the nano-particles produced by combustion and incineration processes is a critical and open challenge. This study addresses the conception, the technological realization and the first experimental testing of a new device suitable for in-duct filtration and separation of nano particles dispersed into flue-gas streams. The active filtering material is a membrane made from ptfe foil, in origin impermeable but suitable to allow creation, once properly stretched, of an inner texture of permeable micro- and nano-tubes, thus inducing activation of van der Waals effects to the advantage of improved particles’ sticking. The experimental tests confirm attainment of a remarkable filtration capacity, way better than the so-called ‘absolute filters’. Moreover, the filtration material allows to undergo a simple and safe “regeneration cleaning”  process by which the particles can be re-collected off-duct without any filter dismantling.

  14. Size dependent fluorescence tuning of naturally occurring betacyanin with silver nano particles

    Sarkar, Arindam; Thankappan, Aparna; Nampoori, V. P. N.

    2014-10-01

    Light absorption and scattering of metal nano partilces occur in very narrow range of wavelengths. This is also dependent on the geometry and shape of metal nano particles. It is also known that scattering is related to (volume)2 and absorption is related to the volume of the spherical metal nano particles. In our work we show that using this principle metal nano particles enable fluorescence tuning of dyes. In our experiment we show such tuning in naturally occurring betacyanin extracted from red beetroot. We also show that such tuning is dependent on the size variation of the silver nano particles.

  15. Cobalt doped antimony oxide nano-particles based chemical sensor and photo-catalyst for environmental pollutants

    Graphical abstract: A dichloromethane chemical sensor using cobalt antimony oxides has been fabricated. This sensor showed high sensitivity and will be a useful candidate for environmental and health monitoring. Also it showed high photo-catalytic activity and can be a good candidate as a photo-catalyst for organic hazardous materials. Highlights: ► Reusable chemical sensor. ► Green environmental and eco-friendly chemi-sensor. ► High sensitivity. ► Good candidate for environmental and health monitoring. - Abstract: Cobalt doped antimony oxide nano-particles (NPs) have been synthesized by hydrothermal process and structurally characterized by utilizing X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and Fourier transforms infrared spectrophotometer (FT-IR) which revealed that the synthesized cobalt antimony oxides (CoSb2O6) are well crystalline nano-particles with an average particles size of 26 ± 10 nm. UV–visible absorption spectra (∼286 nm) were used to investigate the optical properties of CoSb2O6. The chemical sensing of CoSb2O6 NPs have been primarily investigated by I–V technique, where dichloromethane is used as a model compound. The analytical performance of dichloromethane chemical sensor exhibits high sensitivity (1.2432 μA cm−2 mM−1) and a large linear dynamic range (1.0 μM–0.01 M) in short response time (10 s). The photo catalytic activity of the synthesized CoSb2O6 nano-particles was evaluated by degradation of acridine orange (AO), which degraded 58.37% in 200 min. These results indicate that CoSb2O6 nano-particles can play an excellent research impact in the environmental field.

  16. Cobalt doped antimony oxide nano-particles based chemical sensor and photo-catalyst for environmental pollutants

    Jamal, Aslam [Centre for Advanced Materials and Nano-Engineering (CAMNE) and Department of Chemistry, Faculty of Sciences and Arts, Najran University, P. O. Box 1988, Najran 11001 (Saudi Arabia); Rahman, Mohammed M. [Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Khan, Sher Bahadar, E-mail: drkhanmarwat@gmail.com [Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Faisal, Mohd. [Centre for Advanced Materials and Nano-Engineering (CAMNE) and Department of Chemistry, Faculty of Sciences and Arts, Najran University, P. O. Box 1988, Najran 11001 (Saudi Arabia); Akhtar, Kalsoom [Division of Nano Sciences and Department of Chemistry, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Rub, Malik Abdul; Asiri, Abdullah M.; Al-Youbi, Abdulrahman O. [Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia)

    2012-11-15

    Graphical abstract: A dichloromethane chemical sensor using cobalt antimony oxides has been fabricated. This sensor showed high sensitivity and will be a useful candidate for environmental and health monitoring. Also it showed high photo-catalytic activity and can be a good candidate as a photo-catalyst for organic hazardous materials. Highlights: Black-Right-Pointing-Pointer Reusable chemical sensor. Black-Right-Pointing-Pointer Green environmental and eco-friendly chemi-sensor. Black-Right-Pointing-Pointer High sensitivity. Black-Right-Pointing-Pointer Good candidate for environmental and health monitoring. - Abstract: Cobalt doped antimony oxide nano-particles (NPs) have been synthesized by hydrothermal process and structurally characterized by utilizing X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and Fourier transforms infrared spectrophotometer (FT-IR) which revealed that the synthesized cobalt antimony oxides (CoSb{sub 2}O{sub 6}) are well crystalline nano-particles with an average particles size of 26 {+-} 10 nm. UV-visible absorption spectra ({approx}286 nm) were used to investigate the optical properties of CoSb{sub 2}O{sub 6}. The chemical sensing of CoSb{sub 2}O{sub 6} NPs have been primarily investigated by I-V technique, where dichloromethane is used as a model compound. The analytical performance of dichloromethane chemical sensor exhibits high sensitivity (1.2432 {mu}A cm{sup -2} mM{sup -1}) and a large linear dynamic range (1.0 {mu}M-0.01 M) in short response time (10 s). The photo catalytic activity of the synthesized CoSb{sub 2}O{sub 6} nano-particles was evaluated by degradation of acridine orange (AO), which degraded 58.37% in 200 min. These results indicate that CoSb{sub 2}O{sub 6} nano-particles can play an excellent research impact in the environmental field.

  17. Microstructure and Behaviors of Nano Composite Coating

    ZHOU Xi-ying; QIAN Shi-qiang; LI Wei-hong; LI Pei-yao; LI Man-ping

    2004-01-01

    Nano composite coatings are fabricated by electro brush plating containing various nano particles (Al2O3, SiO2and ZrO2). Its surface morphology and microstructure are observed by means of S-2700 scanning electron microscopy (SEM). And the mechanical behaviors of nano composite coating are analyzed. The results show that microstructure of nano composite coating is obviously fine because of nano particles. Micro hardness at room temperature increases with the increase of nano particles content. The wear resistance and hardness at high temperature are also improved. The strengthening effect is differentiated by the type and content of nano particles. This is due to the combination of dispersion strengthening and grain size strengthening.Key Words: Nano particles, composite coating, electro brush plating, behaviors

  18. ON THE EFFECT OF NANO-PARTICLE CLUSTERING ON TOUGHENING OF NANO-COMPOSITE CERAMICS

    董照旭; 方岱宁; 苏爱嘉

    2002-01-01

    In this paper, two and three-dimensional clustering models are developed to characterize the effect of nano-particle clustering on toughening of nanocomposite ceramics. It is found that crack pinning toughens the nano-composite ceramics because a higher stress intensity factor is needed for crack to propagate around or to pull-out the nano-particle. The nano-particle along the grain boundary steers the crack into the matrix grain due to the strong cohesion between the nanoparticle and the matrix. Since the fracture resistance of the grain boundary is lower than that of the grain lattice, the higher the probability of transgranular fracture induced by nano-particles, the tougher is the nano-composite. However, both crack pinning and transgranular fracture are affected by nano-particle clustering. Nanoparticle clustering, which increases with increasing volume fraction of nano-particles,leads to reduction of both the strength and toughness of the nano-composite ceramics. The larger the size of the clustered particle, and the more defects it contains, the easier it is for the crack to pass through the clustered particle, which means that the nano-particle clustering can reduce toughening induced by crack pinning and transgranular fracture. The theoretical prediction, based on the combination of the three mechanisms of nano-particles, is in agreement with the experimental data.

  19. Biosynthesis of Silver Nano Particles from Fusarium oxysporum Culture

    Rita Singh Majumdara

    2015-12-01

    Full Text Available From a very long time inhibitory effect of silver has been recognized and used towards many bacterial strains and microorganisms commonly present in medical and industrial processes. The most useful and important characteristic of silver is its antimicrobial property. In the current study silver nano particles with uniform size distribution of 10-20nm with stability and promising increase in yield were obtained and effect of cultural and physical conditions on biological synthesis of SNPs was studied. SNPs (Silver Nanoparticles synthesis was first analysed out by visual observation of colour change of the fungal filtrate after treatment with silver nitrate (AgNO3 solution within 24hrs. Formation of dark brown colour of fungal cell filtrate indicated the presence of SNPs (Silver Nanoparticles.

  20. Enhancement of iron content in spinach plants stimulated by magnetic nano particles

    Yulianto, Agus; Astuti, Budi; Amalia, Saptaria Rosa

    2016-04-01

    In our previous study, the iron content in spinach plants could be detected by magnetic susceptibility values. In the present work, magnetic nano particles were found from the iron sand. The magnetic nano particles are synthesis by using co-precipitation process and sol-gel technique. The stimulation of magnetic nano particles in the plant has been done by the provision of magnetic nano particles in growing media. After certain time, plant samples was characterized using susceptibility-meter MS2B and atomic absorption spectroscopy to measure the magnetic susceptibility and the amount of iron content that absorbed of the plant, respectively. The iron content in the spinach plants was increased when the magnetic nano particles was injected in the growing media.

  1. Development of a method to lower recontamination after chemical decontamination by depositing Pt nano particles

    The Pt coating (Pt-C) process has been developed to lower recontamination by radioactive elements after chemical decontamination of piping surfaces. In this process, a layer of fine Pt nano particles is formed in aqueous solution on the base metal of the piping following the chemical decontamination. In this study, we confirmed the suppression effect by the Pt-C toward 60Co deposition on type 316 stainless steel using a 60Co deposition test under hydrogen water chemistry. The deposition amounts of 60Co which were incorporated in oxides after 1000 h with and without the Pt-C process were about 90 and 10.2 Bq/cm2, respectively. The amount of 60Co deposition with Pt-C is about 10% that of non-coated specimens. The 60Co incorporation for the Pt-C specimen was suppressed by decreasing the formation of oxides. We considered this phenomenon from experimental results and concluded that oxides were chemically reduced by the effect of Pt and hydrogen radicals which were produced in the reaction between H2 and Pt, and then oxides were dissolved into the water. (author)

  2. Agglomeration Evolution of Nano-Particles Aluminium in Normal Incident Shock Wave

    YAN Zheng-Xin; WU Jing-He; HU Dong; YANG Xiang-Dong

    2006-01-01

    Agglomeration behaviour of nano-particle aluminium (nano-Al) in normal incident shock waves is investigated by our devised shock tube technology. The morphology, particle size, agglomeration process of nano-Al studied in normal incident shock waves are comprehensible evaluated by x-ray diffraction, transmission electron microscopy and scanning electron microscopy. The above-mentioned techniques show that the high strength and temperature of incident shock wave give a chance for activity of nano-Al in the reactions and decrease the agglomeration, and the morphology of agglomeration is affected by the temperature of nano-Al reaction region. The dynamic temperature of reaction region determined by the intensity ratio of two AlO bands is 2602K, which is closer to nano-Al actual reacted temperature than the determined temperature of ordinary methods (i.e. six channel instantaneous optical pyrometer; plank black body radiation law, etc.)

  3. Protective effects of orally applied fullerenol nano particles in rats after a single dose of doxorubicin

    Ičević Ivana Đ.

    2011-01-01

    Full Text Available Polyhydroxylated, water soluble, fullerenol C60(OH24 nano particles (FNP in vitro and in vivo models, showed an expressive biological activity. The goal of this work was to investigate the potential protective effects of orally applied FNP on rats after a single dose of doxorubicin (DOX (8 mg/kg (i.p. 6 h after the last application of FNP. After the last drug administration, the rats were sacrificed, and the blood and tissues were taken for the analysis. Biochemical and pathological results obtained in this study indicate that fullerenol (FNP, in H2O:DMSO (80:20, w/w solution given orally in final doses of 10, 14.4, and 21.2 mg/kg three days successively, has the protective (hepatoprotective and nephroprotective effect against doxorubicin-induced cytotoxicity via its antioxidant properties.

  4. High saturation magnetization of γ-Fe2O3 nano-particles by a facile one-step synthesis approach.

    Cao, Derang; Li, Hao; Pan, Lining; Li, Jianan; Wang, Xicheng; Jing, Panpan; Cheng, Xiaohong; Wang, Wenjie; Wang, Jianbo; Liu, Qingfang

    2016-01-01

    We have demonstrated the synthesis of γ-Fe2O3 nano-particles through a facile and novel calcination process in the air. There is no pH regulation, gas atmosphere, additive, centrifugation or other complicated procedures during the preparing process. A detailed formation process of the nano-particles is proposed, and DMF as a polar solvent may slower the reaction process of calcination. The structures, morphologies, and magnetic properties of γ-Fe2O3 nano-particles were investigated systematically, and the pure γ-Fe2O3 nano-particles obtained at 200 °C display uniform morphology good magnetic property. The saturation magnetization of obtained pure γ-Fe2O3 is about 74 emu/g, which is comparable with bulk material (76 emu/g) and larger than other results. In addition, the photocatalytic activity for degradation of methylene blue is also studied, which shows proper photocatalytic activity. PMID:27581732

  5. 18F-radiolabeled RGD-A7R-conjugated nano-particles for integrin and VEGF-targeted tumor imaging

    Radiolabeled RGD-A7R has been extensively investigated for tumor integrin avb3 and VEGF imaging. In this paper, we designed and synthesized a radiolabeled nano-particle that coated with RGD-A7R. The aim of this study was to evaluate if nano-particles has an advantage in vivo kinetics comparing with RGD-A7R monomers. The targeting properties of 18F-n-BSA-RGD-A7R were tested in U87MG tumor models. The tumor uptake of 18F-n-BSARGD-A7R was high compared with background. The improved pharmacokinetics of 18F-n-BSA-RGD-A7R confirmed that the application of nano-technology is effective to develop promising imaging agents for the no-invasive detection. (author)

  6. Antitumor Effect of Selenium and Modified Pectin Nano Particles and Gamma Radiation on Ehrilch Solid Tumor in Female Mice

    Selenium nano particle (Nano- Se) is a novel Se species with novel biological activities with low toxicity. The aim of the present work was to evaluate the antitumor activity of a novel Nano- Se compound with or without gamma irradiation of female mice. Selenium size- controlled Nano-Se was prepared by a simple method by adding modified pectin to the selenious acid and ascorbic acid. The antitumor activity of Selenium and Modified Pectin Nano Particles (Se-Mp- NPs) were evaluated against Ehrilch ascites carcinoma (In vitro) and Ehrilch solid tumor model (In vivo). The antioxidant states of the novel compound were assessed measuring parameters in blood and tumor tissue of female mice. Malonaldehydoyl (MDA) end product of lipid peroxidation was evaluated in plasma and tumor tissue. Glutathione -S- transferase (GST) and cytochrome P450 (Cyto P450) were determined in tumor tissue homogenate. Tumor necrosis factor alpha (TNF- a) concentration and interleukin 10 (IL- 10) concentrations was evaluated in plasma of female mice. The effect of tumor inoculation and different treatments on liver enzymes (ALT and AST) and kidney Function (urea and creatinine) were detected in the plasma of animals. Apoptosis was shown and estimated in tumor tissue of animals histopathological of tumor in different groups of mice were examined. Ehrilch solid tumor induced a significant increase in MDA content, GSH-Px and GST activities level and in the amount of metabolites of CYP 450. Moreover, a significant decrease was observed in GSH content, SOD activity level in the tumor tissue, INF- a concentration, IL- 10 concentration in the plasma. Also, a significant alteration in kidney and liver functions was occurred as compared to control group. The results showed a significant antitumor activity of selenium and Modified Pectin Nano Particles (Se-Mp- NPs) at the concentration 2.25 μg / ml was 70%

  7. Nucleation and dissociation of nano-particles in gas phase

    This work deals with the study of nano-particles formation in gas phase and their dissociation pathways after an optical excitation. The clusters formation decomposes in two steps: a seed is formed (nucleation phase) and sticks atoms during its propagation in a sodium atomic vapor (growth phase). Those two steps have been observed separately for homogeneous Nan and heterogeneous NanX particles (X = (NaOH)2 or (Na2O)2). The growth mechanism is well interpreted by a Monte Carlo simulation taking into account an accretion mechanism with hard-sphere cross section. The homogeneous nucleation mechanism has been highlighted by a direct comparison with the Classical Nucleation Theory predictions. The clusters fragmentation of ionic Na+(NaOH)p et Na+(NaF)p particles is studied in the second part. The way clusters fragment with size when they are excited optically is compared with theoretical previsions: this highlights the existence of an energetic barrier for special size of clusters. Finally, the fragmentation of doubly charged Na+ Na+ (NaOH)p clusters shows a competition between the fission into two single charged fragments and the unimolecular evaporation of a neutral fragment. (author)

  8. Fabrication of composite nano-particles by radiations

    Realization of composite nano-materials using radiation technology is reported to demonstrate one of the author's experimental results on noble-metallic nano-particles having the diameter less than 10 nm which are dispersed homogeneously with high density on a catalyst-supporting particle. Keeping away as such from coagulation of noble metals, thus keeping its high specific surface, functional materials, for example, magnetic materials can be used as a supporting particle. The method is to irradiate the solutions containing starting materials. Since water containing 2-propanol is decomposed by radiolysis to produce the reducing and oxidizing species, metallic ions will be reduced to metals and sometimes in the presence of polyvinyl alcohol to noble-metal colloidal solutions which has been further applied to synthesis of Au/γ-Fe2O3 composite particle. Moreover, other metals as Ag, Pt, Pd, Rh, with other supporting materials as Al2O3, TiO2, Fe3O4, ZnO, ZrO2, and CeO2 were found to be realized. Au/iron oxides magnetic composite particles were also synthesized by γ- or electron irradiation to be used magnetically separate the mixture of amino acids and DNA. (S. Ohno)

  9. Nano-lens diffraction around a single heated nano particle

    Markus, Selmke; Frank, Cichos

    2011-01-01

    The action of a nanoscopic spherically symmetric refractive index profile on a focused Gaussian beam may easily be envisaged as the action of a phase-modifying element, i.e. a lens: Rays traversing the inhomogeneous refractive index field n(r) collect an additional phase along their trajectory which advances or retards their phase with respect to the unperturbed ray. This lens-like action has long been understood as being the mechanism behind the signal of thin sample photothermal absorption measurements [1, 2], where a cylindrical symmetry and a different lengthscale is present. In photothermal single (nano-)particle microscopy, however, a complicated, though prediction-wise limited, electrodynamic (EM) scattering treatment was established [3] during the emergence of this new technique. Our recent study extended [4] this EM-approach into a full ab-initio model describing the reality of the situation encountered and showed for the first time that the mechanism behind the signal, despite its nanoscopic origin,...

  10. Synthesis of supported metallic nano-particles and their use in air depollution

    The main objectives of the 'NACACOMO' Consortium ('Nano-materials: Catalysts for the Conversion of organic Molecules. Uses in fine chemicals and environment protection ') consisted in generating novel catalysts composed of nanoparticles of metals (Pt, Pd, Ag...) and/or oxides (TiO2...) stabilized and well distributed over the surface of a support (foams, ceramics), by monitoring both the particle size and the 'coating' process itself, using new technologies: CVD, plasma-spray, laser pyrolysis, supercritical preparation, which were compared to conventional soft chemistry recipes. The most accurate characterization of particle morphology, local structure, texture, spatial arrangement but also of their reactivity, were achieved by privileging the utilization of various in situ methods. Details on formation mechanisms of a solid nano-particle at the atomic level (nucleation, growth and particle (re)distribution over the support...) could be obtained in selected cases, with opportunities for scaling up and shaping. The (chemical) nature of the so-obtained nano-materials was monitored for selected catalytic applications involving the development of environmental friendly processes, such as oxidation of VOC, with a priority for aromatics and chlorinated compounds. (authors)

  11. Enhanced dielectric breakdown performances of propylene carbonate modified by nano-particles under microsecond pulses

    Hou, Yanpan; Zhang, Jiande; Zhang, Zicheng

    2016-06-01

    Propylene carbonate shows appealing prospects as an energy storage medium in the compact pulsed power sources because of its large permittivity, high dielectric strength, and broad operating temperature range. In this paper, TiO2 nano-particles coated with γ-aminopropyltriethoxylsilane coupling agent are homogeneously dispersed into propylene carbonate and these nano-fluids (NFs) exhibit substantially larger breakdown voltages than those of pure propylene carbonate. It is proposed that interfaces between nano-fillers and propylene carbonate matrix may provide myriad trap sites for charge carriers. The charge carriers can be easily captured at the interfaces between NFs and the electrode, resulting in an increased barrier height and suppressed charge carriers injection, and in the bulk of NFs, the charge carriers' mean free path can be greatly shortened by the scattering effect. As a result, in order for charge carriers acquiring enough energy to generate a region of low density (the bubble) and initiate breakdown in NFs, much higher applied field is needed.

  12. MR Relaxivity Measurement of Iron Oxide Nano-Particles for MR Lymphography Applications

    K. Firouznia

    2008-01-01

    Full Text Available The aim of this study was to assess the T1, T2 and T2* relaxivity of Ultrasmall Super Paramagnetic Iron Oxide (USPIO nano-particles in vitro and in vivo in rat models with magnetic resonance imaging at 1.5T. First, relaxation properties of USPIO nano-particles at different doses were measured using related SE and GRE MR imaging protocols. The relation between dose and relaxation were observed which is linear; Higher dose of the nano-particles means higher relaxivity. Based on this relation, an optimum protocol can be proposed for obtaining the best image contrast at each situation. Then detection ability of MRI protocols was studied for USPIO nano-particles with injection of the particles in the rat. The optimum MR protocols were used to observe the signal change of lymph nodes in rat.

  13. Nonaqueous preparation of stable silver nano particles dispersions from organic sulfonic acids.

    Valentina Glushko

    2016-05-01

    Full Text Available The conditions for stable silver nano particles dispersions synthesis from organic sulfonic acids in an anhydrous medium of ethylene glycol and its methyl ester were studied. Ascorbic acid and potassium citrate were used as reducing agents.

  14. Determination of Size Distribution of Nano-particles by Capillary Zone Electrophoresis

    Yan XUE; Hai Ying YANG; Yong Tan YANG

    2005-01-01

    A new method was developed for the determination of the size distribution of nano-particles by capillary zone electrophoresis (CZE). Scattering effect of nanoparticles was studied. This method for the determination of size distribution was statistical.

  15. Effects of Gamma Irradiation and Silver Nano Particles on Microbiological Characteristics of Saffron, Using Hurdle Technology

    Hamid Sales, E.; Motamedi Sedeh, F.; Rajabifar, S.

    2011-01-01

    Saffron, a plant from the Iridaceae family, is the world’s most expensive spice. Gamma irradiation and silver nano particles whose uses are gradually increasing worldwide, have positive effects on preventing decay by sterilizing the microorganisms and by improving the safety without compromising the nutritional properties and sensory quality of the foods. In the present study combination effects of gamma irradiation and silver nano particles packaging on the microbial contamination of saffron...

  16. Ultraviolet spectra of CeO2 nano-particles

    Full text: Quantum size effect is generally expected in nanometer size materials. The effect has been observed in many metal clusters and semiconducting nano-particles, but seldom in oxides, because the size control of crystalline oxides is generally difficult due to the ionic bond character. CeO2 (ceria) is one of the rare-earth oxides and the size effect is worth studying from the viewpoint of an ultraviolet (u.v.) spectroscopy and applications. This report describes the first observation of a blue shift of u.v. spectra in ceria nano-particles of 2-5 nm in diameter with its deviation within 20%. A ceria aqueous sol (pH ≅ 2.5) having particle sizes under 6 nm in diameter was produced by ultrafiltration with a polyether sulfone membrane (SIP-1013, Asahi Chemical Industry Co.) from an original ceria aqueous sol (pH ≅ 1.5) having particle sizes extending over a wide range. Obtained sol contains a high concentration of Ce3+ ions because of the high acidity. In order to separate ceria particles from Ce3+ ions and fractionate the particle size, two kinds of anion-type surfactants were used in microemulsification process with toluene and water. One is sodium dodecylbenzene sulfonate (SD-BS) which is 2 nm in length and another is sodium octyl sulfonate (SOS) which is 1.2 nm in length. U.v. spectroscopic measurements and high resolution transmission electron microscopic (HRTEM) observations were performed for (SOS)t , (SOS+SOS)t , and (SDBS+SOS+SDBS)t , where (SOS)t is a ceria suspension in toluene obtained by an emulsification with SOS surfactant, (SOS+SOS)t indicates the same product obtained by the further emulsification with SOS for an aqueous phase of the emulsion with SOS, and (SDBS+SOS+SDBS)t means that obtained by an additional emulsification with SDBS for an aqueous phase obtained by two successive emulsifications with SDBS and SOS. Optical density data for (SOS)t , (SOS+SOS)t , and (SDBS+SOS+SDBS)t show absorption edges at 4076 Angstroms, 3997 Angstroms, and

  17. Flame spray synthesis of ZrO2 nano-particles using liquid precursors

    This paper studies the feasibility of using flame spray to produce ZrO2 nano-particles using a liquid precursor. The effects of varying precursor concentrations and ratio of diluting medium on the phase composition, size and morphology of ZrO2 nano-particles are discussed. The morphology and size of the ZrO2 nano-particles was very much dependent on the precursor concentration. The solvent ratio of H2O:ethanol also played a part in determining the characteristics of the ZrO2 nano-particles. The nano-particles had the best characteristics when the precursor concentration was low and ethanol (added as solvent) content was high. In particular, the best characteristics were obtained using precursor concentration of 0.25 M, H2O:ethanol ratio of 0:1. The nano-particles had very small particle size (∼50 nm), relatively high specific surface area (28.6 m2/g) and high degree of crystallinity. However, particles synthesized tend to be agglomerated

  18. Preclinical spectral computed tomography of gold nano-particles

    Today's state-of the art clinical computed tomography (CT) scanners exclusively use energy-integrating, scintillation detector technology, despite the fact that a part of the information carried by the transmitted X-ray photons is lost during the detection process. Room-temperature semiconductors, like CdTe or CZT, operated in energy-sensitive photon-counting mode provide information about the energy of every single X-ray detection event. This capability allows novel, promising approaches to selectively image abnormal tissue types like cancerous tissue or atherosclerotic plaque with the CT modality. In this article we report on recent dual K-edge imaging results obtained in the domain of pre-clinical, energy-sensitive photon-counting CT. In this approach, the tuning of threshold levels in the detector electronics to the K-edge energy in the attenuation of contrast agents (CA) offers highly specific, quantitative imaging of the distribution of the CA on top of the conventional, morphological image information. The combination of the high specificity of the K-edge imaging technique together with the powerful tool of targeting specific diseases in the human body by dedicated contrast materials might enrich the CT modality with capabilities of functional imaging known from the nuclear medicine imaging modalities, e.g., positron-emission-tomography but with the additional advantage of high spatial and temporal resolution. We also discuss briefly the technological difficulties to be overcome when translating the technique to human CT imaging and present the results of simulations indicating the feasibility of the K-edge imaging of vulnerable plaque using targeted gold nano-particles as contrast materials. Our experiments in the pre-clinical domain show that dual-K edge imaging of iodine and gold-based CAs is feasible while our simulations for the imaging of gold CAs in the clinical case support the future possibility of translating the technique to human imaging.

  19. Preclinical spectral computed tomography of gold nano-particles

    Roessl, Ewald; Cormode, David; Brendel, Bernhard; Jürgen Engel, Klaus; Martens, Gerhard; Thran, Axel; Fayad, Zahi; Proksa, Roland

    2011-08-01

    Today's state-of the art clinical computed tomography (CT) scanners exclusively use energy-integrating, scintillation detector technology, despite the fact that a part of the information carried by the transmitted X-ray photons is lost during the detection process. Room-temperature semiconductors, like CdTe or CZT, operated in energy-sensitive photon-counting mode provide information about the energy of every single X-ray detection event. This capability allows novel, promising approaches to selectively image abnormal tissue types like cancerous tissue or atherosclerotic plaque with the CT modality.In this article we report on recent dual K-edge imaging results obtained in the domain of pre-clinical, energy-sensitive photon-counting CT. In this approach, the tuning of threshold levels in the detector electronics to the K-edge energy in the attenuation of contrast agents (CA) offers highly specific, quantitative imaging of the distribution of the CA on top of the conventional, morphological image information. The combination of the high specificity of the K-edge imaging technique together with the powerful tool of targeting specific diseases in the human body by dedicated contrast materials might enrich the CT modality with capabilities of functional imaging known from the nuclear medicine imaging modalities, e.g., positron-emission-tomography but with the additional advantage of high spatial and temporal resolution. We also discuss briefly the technological difficulties to be overcome when translating the technique to human CT imaging and present the results of simulations indicating the feasibility of the K-edge imaging of vulnerable plaque using targeted gold nano-particles as contrast materials. Our experiments in the pre-clinical domain show that dual-K edge imaging of iodine and gold-based CAs is feasible while our simulations for the imaging of gold CAs in the clinical case support the future possibility of translating the technique to human imaging.

  20. Flux pinning properties of YBCO films with nano-particles by TFA-MOD method

    Masuda, Y.; Teranishi, R.; Matsuyama, M.; Yamada, K.; Kiss, T.; Munetoh, S.; Yoshizumi, M.; Izumi, T.

    Nano-particles were doped into YBCO films as pinning centers by a metal organic deposition (MOD) method using trifluoroacetates. Two types of initial solution with a cation ratio of Y: Ba: Cu = 1: 1.5: 3 were prepared; one with the dispersion of SnO2 particles with the size of 15-25 nm and the other one with the dispersion of smaller ZrO2 particles with the size of under 8 nm, then the solution was spin-coated on CeO2/Gd2Zr2O7/Hastelloy substrates. The coated films were calcined at 430 °C in oxygen atmosphere and crystallized at 780 °C in low oxygen atmosphere. From the results of X-ray diffraction analysis (XRD), peaks of BaSnO3 were observed clearly in the YBCO film by the starting solution with SnO2. On the other hands, little peaks corresponding to BaZrO3 were observed in the film by the solution with ZrO2. Many CuO segregations were recognized at the surface of SnO2 doped YBCO film in comparison to the YBCO film with ZrO2 doping. From these results, it is indicated that most of SnO2 particles in precursors are react with Ba during heating. Critical current density (JC) of the YBCO films by both solutions showed higher performance than that of pure YBCO film in magnetic fields.

  1. Modeling of an Active Tablet Coating Process.

    Toschkoff, Gregor; Just, Sarah; Knop, Klaus; Kleinebudde, Peter; Funke, Adrian; Djuric, Dejan; Scharrer, Georg; Khinast, Johannes G

    2015-12-01

    Tablet coating is a common unit operation in the pharmaceutical industry, during which a coating layer is applied to tablet cores. The coating uniformity of tablets in a batch is especially critical for active coating, that is, coating that contains an active pharmaceutical ingredient. In recent years, discrete element method (DEM) simulations became increasingly common for investigating tablet coating. In this work, DEM was applied to model an active coating process as closely as possible, using measured model parameters and non-spherical particles. We studied how operational conditions (rotation speed, fill level, number of nozzles, and spray rate) influence the coating uniformity. To this end, simulation runs were planned and interpreted according to a statistical design of (simulation) experiments. Our general goal was to achieve a deeper understanding of the process in terms of residence times and dimensionless scaling laws. With that regard, the results were interpreted in light of analytical models. The results were presented at various detail levels, ranging from an overview of all variations to in-depth considerations. It was determined that the biggest uniformity improvement in a realistic setting was achieved by increasing the number of spray nozzles, followed by increasing the rotation speed and decreasing the fill level. PMID:26344941

  2. Effect of Au nano-particle aggregation on the deactivation of the AuCl3/AC catalyst for acetylene hydrochlorination.

    Dai, Bin; Wang, Qinqin; Yu, Feng; Zhu, Mingyuan

    2015-01-01

    A detailed study of the valence state and distribution of the AuCl3/AC catalyst during the acetylene hydrochlorination deactivation process is described and discussed. Temperature-programmed reduction and X-ray photoelectron spectral analysis indicate that the active Au(3+) reduction to metallic Au(0) is one reason for the deactivation of AuCl3/AC catalyst. Transmission electron microscopy characterization demonstrated that the particle size of Au nano-particles increases with increasing reaction time. The results indicated that metallic Au(0) exhibits considerable catalytic activity and that Au nano-particle aggregation may be another reason for the AuCl3/AC catalytic activity in acetylene hydrochlorination. PMID:25994222

  3. Diagnostics of Nano-Particle Formation in Process Plasmas

    Kersten, Holger

    2015-09-01

    in the plasma during the growth cycles has been monitored by microwave interfereomtery and the nano-particle formation and deposition was observed in-situ by XPS and NEXAFS at a synchrotron beamline. In collaboration with E. von Wahl, A. Hinz, T. Strunskus, V. Schneider, and T. Trottenberg, Institute of Experimental and Applied Physics, University of Kiel, Kiel, Germany.

  4. Fractures as Carriers for Colloid and Nano-Particles

    Weisbrod, N.; Cohen, M.; Tang, X.; Zvikelsky, O.; Meron, H.

    2013-12-01

    One of the major questions in studies in which transport of colloids and nano particles (NPs) is being explored is whether or not they will be mobile on large scales and in large conduits such as fractures and cracks. While many studies explore the migration on a small scale and mostly in ideal porous media, less is known about this topic on larger scales and in fractured rocks or cracked soils. Fractures are likely to be favorable carriers for colloids and NPs due to their large aperture, enabling relatively high flow velocity and smaller tortuosity of the flow path. Transport of various colloids including microspheres, clay particles and viruses, as well as colloid-facilitated transport of lead and cesium was explored in a naturally discrete fractured chalk cores. Preliminary work exploring the transport of NZVIs and TiO2 NPs is being carried out through these cores as well. Our results indicate very high recovery of large microspheres (0.2 and 1 micron) and lower recovery of the small spheres (0.02 micron). It was observed that clay particles, with similar surface properties and sizes to that of the microspheres, show significantly lower recoveries (50 vs over 90%), probably due to the high density of clay particles in respect to the microspheres (2.65 vs. 1.05 g/cm3). High recovery of bacteriophages was also observed, but they exhibit some differences in respect to microspheres with similar properties. In all cases, including the 0.02 micron colloids exhibiting lower recovery rates, arrival times were earlier than that of the bromide that was used as a reference. It was found that colloid-facilitated transport played a major role in the migration of lead and cesium through the fracture. In practice, lead was found to be mobile only in a colloidal form. The on-going work on NP transport through fractures is still in a preliminary phase. Nevertheless, TiO2 recovery was found to be very low. In conclusion, it was observed that in many cases fractures are favorable

  5. Enzymatic transesterification of soybean oil by using immobilized lipase on magnetic nano-particles

    Lipase was covalently immobilized onto magnetic Fe3O4 nano-particles by using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as an activating agent, and the bound lipase was used to catalyze the transesterification of vegetable oils with methanol to produce fatty acid methyl esters. The binding of lipase to magnetic particles was confirmed by enzyme assays, transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectra. It was determined that the immobilized lipase exhibited better resistance to temperature and pH inactivation in comparison to free lipase. Using the immobilized lipase, the major parameters affecting the transesterification reaction, such as the alcohol/oil molar ratio, enzyme loading and free fatty acid present in reactants were investigated to obtain the optimum reaction condition. The conversion of soybean oil to methyl esters reached over 90% in the three-step transesterification when 40% immobilized lipase was used. Moreover, the lipase catalyst could be used for 3 times without significant decrease of the activity.

  6. Effect of Au nano-particle aggregation on the deactivation of the AuCl3/AC catalyst for acetylene hydrochlorination

    Bin Dai; Qinqin Wang; Feng Yu; Mingyuan Zhu

    2015-01-01

    A detailed study of the valence state and distribution of the AuCl3/AC catalyst during the acetylene hydrochlorination deactivation process is described and discussed. Temperature-programmed reduction and X-ray photoelectron spectral analysis indicate that the active Au3+ reduction to metallic Au0 is one reason for the deactivation of AuCl3/AC catalyst. Transmission electron microscopy characterization demonstrated that the particle size of Au nano-particles increases with increasing reaction...

  7. Photopyroelectric Techniques for thermo-optical characterization of gold nano-particles

    Since the first methodology, proposed by Turkevich, to produce gold nanoparticles (AuNPs), improvements have been made as to allow better controllability in their size and shape. These two parameters play important role for application of gold nanoparticles since they determine their optical and thermal properties. Two photopyroelectric techniques for the measurement of the thermal diffusivity and the optical absorption coefficient for nano-particles are introduced. These thermo-physical properties were measured for the colloidal systems at different nano-particle's sizes and, for optical properties, at three different wavelengths (405 nm, 488 nm and 532 nm). No significant difference, on thermal properties, was found in the range of nano-particles' sizes studied in this work; in opposition optical properties shown more sensitive to this parameter

  8. Microstructure and Behaviors of Nano Composite Coating

    ZHOUXi-ying; QIANShi-qiang; LiWei-hong; LIPei-yao; LIMan-ping

    2004-01-01

    Nano composite coatings are fabricated by electro brash plating containing various nano particles (Al2O3, SiO2 and ZrO2). Its surface morphology and microstructure are observed by means of S-2700 scanning elect-on microscopy (SEMI, And the mechanical behaviors of nano composite coating are analyzed. The results show that microstructure of nano composite coating is obviously fine because of nano particles. Micro hardness at room temperature increases with the increase of nano particles content. The wear resistance and hardness at high temperature are also improved. The strengthening effect is differentiated by the type and content of nano particle.s, This is due to the combination of dispersion strengthening and grain size strengthening.

  9. Synthesis and characterization of La2O3 nano particles for future CMOS applications

    This research paper deals with the preliminary studies on synthesis and characterization of lanthanum oxide or lanthana (La2O3) nano particles by chemical combustion using urea as fuel. The fuel urea is varied for different fuel to oxidizer ratios (O/F) or Ψ. The starting material (oxidizer) is the lanthanum nitrate (La(NO3)3.6H2O) and fuel as urea. The synthesized lanthana nano particles were characterized by X-ray diffraction (XRD) for crystal structure analysis, scanning electron microscopy (SEM) for morphological and particle size determination. (author)

  10. Size measurement of nano-particles using self-mixing effect

    Huarui Wang; Jianqi Shen

    2008-01-01

    In this letter, the technique of laser self-mixing effect is employed for nano-particle size analysis. In contrast to the photon correlation spectroscopy (PCS) and photon cross correlation spectroscopy (PCCS),the main advantages of this technique are sensitive, compact, low-cost, and simple experimental setup etc.An improved Kaczmarz projection method is developed in the inversion problem to extract the particle size distribution. The experimental results prove that nano-particle size can be measured reasonably by using the self-mixing effect technique combined with the improved projection algorithm.

  11. Biological Experiments in Microgravity Conditions Using Magnetic Micro- and Nano-Particles

    Nechitailo, Galina S.; Kuznetsov, Anatoli; Kuznetsov, Oleg

    2016-07-01

    even for weak magnetic objects, and can have significant effects on multiple processes in living cells/organisms. It was reported, that such high gradient magnetic fields can affect cell differentiation and cell proliferation processes in ground-based experiments. To prevent oxidation of ultradisperse ferromagnetic particles in aqueous media, it is beneficial to coat their surface with carbon. Suitable protected metallic micro- and nano-particles can be produced by a variety of techniques (CVD, plasmachemistry, joint grinding, etc.). Ferro-carbon particles produced by plasmachemical technique have high sorption capacities for various organic and inorganic compounds (as well as for various cell metabolites), can be formed in rather stable aqueous suspensions, and be controlled (e.g., sedimented) by a magnetic field. This makes these particles a very interesting research tool. In our opinion, biological experiments with ferro-carbon nano-structured particles in microgravity will generate important scientific data and will allow creating new methods of negating the adverse effects of microgravity on living systems.

  12. In situ, high-pressure differential thermal analysis and ionic conductance of PMMA-based gels with and without TiO2 nano-particle filler

    The transition behaviours of PMMA-based gels with and without nano-particle filler have been investigated at elevated pressures up to 0.9 GPa and in the temperature range 220-310 K. Both gels had molar ratios of 53.9:22:5.2:18.9 of ethylene carbonate (EC), propylene carbonate (PC), lithium perchlorate, PMMA, and one gel contained 8 wt.% TiO2 nano-particles. The results show a sluggish transition between a low-pressure (high temperature) state and a high-pressure (low temperature) state. The nano-particle filler facilitates the kinetics of the transition, yielding a significantly lower transition pressure as well as a better homogeneity in the sample after a transition back to the low-pressure state. These results can be explained by a filler-induced increase of the nucleation rate, which yields smaller crystallites. The transition is observed also by differential scanning calorimetry and Raman spectroscopy at ambient pressure and is likely associated with crystallization of the EC-PC solvent. The logarithmic pressure derivative of the conductance and, consequently, the activation volume changes a factor of 3 as a result of the transition

  13. Effect of Partial Orientation in [100] Direction on the Magnetic Properties of Co-Ferrite Prepared from Nano Particles

    H. M. El-Sayed

    2009-01-01

    Chemical co-precipitation method was used for the preparation of Co-ferrite nano particles. The particle size was about 14 nm. A magnetic anisotropy of Co-ferrite could be increased obtained by applying an external magnetic field during the pressing of the nano particles before the final sintering. This anisotropy enhanced the squareness and the coercivity of investigated samples.

  14. The role of biological processes in the synthesis of plant origin of magnetic nano particles

    Full text:In recent years, in various spheres, particular in the use of medicine and the use of iron oxide (magnetit-Fe3O4, magemit Fe2O3) needed in the diagnostics the problems of synthesis of magnetic nano particles are in the centre of the focus of many scholars.The implementation of biological methods of synthesis of magnetic nano particles, it is very urgent clarification of the role of biological processes synthesis of nano particles. What is the role of biological processes in the synthesis of magnetic nano particles plant in order to clarify the model of the wheat (Triticum vulgare) and pea (Cicer arietinum L.) plants and seeds have been used. The study of the effects of radiation on organisms of different types of cell and chromosome levels of various radiation effects and radiation to understand the nature of the influence of the nature of the forecast allows you to substantiate. Chromosome aberation was has been taken in the cells of pea sprout exposures radiation rays as a criterion of cytogenetic effects. EPR studies of the pea and wheat seeds (control and radiations) were used. In accordance with the results of EPR experiments were carried out with pea seeds.

  15. Growth of Sulfuric Acid Nano-Particles at Dry and Wet Conditions

    Škrabalová, Lenka; Brus, D.; Ždímal, Vladimír; Lihavainen, H.

    - : -, 2012, P270. [European Aerosol Confrernce EAC 2012. Granada (ES), 02.09.2012-07.09.2012] R&D Projects: GA AV ČR IAA200760905 Institutional support: RVO:67985858 Keywords : sulfuric acid * nano-particles * particle growth Subject RIV: BJ - Thermodynamics http://www.eac2012.com/EAC2012Book/3.html

  16. The combined effect of deuterium depleted water and magnetic nano particles on Vitis vinifera (L) organogenesis

    Full text: The combined effect of Deuterium Depleted Water (DDW) associated with Magnetic Nano Particles (MNPs) on organogenesis evolution of the Vitis vinifera (L) was investigated. A total of 10 cuttings of first year shoots belonging to three varieties were put into liquid medium (500 cm3 / jar) in three experimental groups and one control (C) each in four replications. The experiment was one year long being divided in two parts, laboratory and greenhouse conditions respectively. During the laboratory experiment, no nutrients were added in experimental solutions. The number of roots, sprouts and leafs were determined periodically. The capacity to perform organogenesis depended on genotype. Each of them pointed out a particular behaviour. In lab conditions the shoot number significantly differs in each variety/liquid composition (P≤0.001). In greenhouse condition on Burgund variety the shoot growth was very fast. In 90 pottings the shoots length varied from 7.36±1.88 to 14.39±4.53 cm in DDW and Negative Control (NC). The number of leafs after 3 months varied from 3.75±0.41 to 7.59±0.45 on Silvania NC and Socodor TW and MNPs respectively. The largest leaves area was 20.32±0.04 cm2 on Burgund variety in DDW conditions. The DDW and MNPs repressed the organogenesis on Silvania and Burgund varieties. The association DDW and MNPs enhanced the leaves area. Generally, the single action of DDW enhanced the plantlet traits and improved the chlorophyll content. The single action of DDW or in association with MNPs had a favourable influence in organogenesis, growth and synthesis of chlorophyll involved in metabolic activity. The deuterium amount decreased in leave juice if the plantlets grew in DDW presence. (authors)

  17. Dependence of Quantum Yields on Size of Ag Nano-particle Embedded in BaO Thin Film

    2002-01-01

    Theoretical dependence of the quantum yields on the size of Ag nano-particle distribution from 0.8nm to 37nm embedded in BaO semiconductor is discussed. The calculation results show that the increase in Ag nano-particle diameter leads to the increase of the quantum yield threshold and the emergence of the rough Gaussian form, the results also show that the greater increase in Ag nano-particle diameter causes the emergence of the exact Gaussian form and makes the peaks rise up.

  18. Ion induced transformation of polymer films into diamond-like carbon incorporating silver nano particles; Ioneninduzierte Umwandlung von Polymerschichten zu diamantaehnlichem Kohlenstoff mit darin enthaltenen Silber-Nanopartikeln

    Schwarz, Florian P.

    2010-03-26

    Silver containing diamond-like carbon (DLC) is an interesting material for medical engineering from several points of view. On the one hand DLC provides high mechanical robustness. It can be used as biocompatible and wear resistant coating for joint replacing implants. On the other hand silver has antimicrobial properties, which could reduce post-operative inflammations. However conventional production of Ag-DLC by co-deposition of silver and carbon in a plasma process is problematic since it does not allow for a separate control of nano particle morphology and matrix properties. In this work an alternative production method has been developed to circumvent this problem. In metall-DLC-production by ion implantation into a nano composite, silver nano particles are initially formed in solution and then incorporated within a polymer matrix. Finally the polymer is transformed into DLC by ion implantation. The aspects and single steps of this method were investigated with regard to the resulting material's properties. The goal was to design an economically relevant deposition method. Based on experimental results a model of the transformation process has been established, which has also been implemented in a computer simulation. Finally the antibacterial properties of the material have been checked in a biomedical test. Here a bacterial killing rate of 90% could be achieved. (orig.)

  19. Synthesis of boron carbide nano particles using polyvinyl alcohol and boric acid

    Amir Fathi

    2012-03-01

    Full Text Available In this study boron carbide nano particles were synthesized using polyvinyl alcohol and boric acid. First, initial samples with molar ratio of PVA : H3BO3 = 2.7:2.2 were prepared. Next, samples were pyrolyzed at 600, 700 and 800°C followed by heat treatment at 1400, 1500 and 1600°C. FTIR analysis was implemented before and after pyrolysis in order to study the reaction pathway. XRD technique was used to study the composition of produced specimens of boron carbide. Moreover, SEM and PSA analysis were also carried out to study the particle size and morphology of synthesized boron carbide. Finally, according to implemented tests and analyses, carbon-free boron carbide nano particles with an average size of 81 nm and mainly spherical morphology were successfully produced via this method.

  20. Control of cancer growth using single input autonomous fuzzy Nano-particles

    Fahimeh Razmi

    2015-04-01

    Full Text Available In this paper a single input fuzzy controller is applied on autonomous drug-encapsulated nanoparticles (ADENPs to restrict the cancer growth. The proposed ADENPs, swarmly release the drug in local cancerous tissue and effectively decreases the destruction of normal tissue. The amount of released drug is defined considering to feed backed values of tumor growth rate and the used drug. Some significant characteristics of Nano particles compared to Nano-robots is their ability to recognize the cancerous tissue from the normal one and their simple structure. Nano particles became an attractive topic in Nano science and many efforts have been done to manufacture these particles. Simulation results show that the proposed controlling method not only decreases the cancerous tissue effectively but also reduces the side effects of drug impressively.

  1. Development of functional nano-particle layer for highly efficient OLED

    Lee, Jae-Hyun; Kim, Min-Hoi; Choi, Haechul; Choi, Yoonseuk

    2015-12-01

    Organic light emitting diodes (OLEDs) are now widely commercialized in market due to many advantages such as possibility of making thin or flexible devices. Nevertheless there are still several things to obtain the high quality flexible OLEDs, one of the most important issues is the light extraction of the device. It is known that OLEDs have the typical light loss such as the waveguide loss, plasmon absorption loss and internal total reflection. In this paper, we demonstrate the one-step processed light scattering films with aluminum oxide nano-particles and polystyrene matrix composite to achieve highly efficient OLEDs. Optical characteristics and surface roughness of light scattering film was optimized by changing the mixing concentration of Al2O3 nano-particles and investigated with the atomic force microscopy and hazemeter, respectively.

  2. Implementation of background scattering variance reduction on the RapidNano particle scanner

    van der Walle, P.; Hannemann, S.; Eijk, D.(Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands); Mulckhuyse, W.F.W.; Donck, J.C.J. van der

    2014-01-01

    The background in simple dark field particle inspection shows a high scatter variance which cannot be distinguished from signals by small particles. According to our models, illumination from different azimuths can reduce the background variance. A multi-azimuth illumination has been successfully integrated on the Rapid Nano particle scanner. This illumination method reduces the variance of the background scattering on substrate roughness. It allows for a lower setting of the detection thresh...

  3. Effect of BaTiO3 nano-particles on breakdown performance of propylene carbonate

    Hou, Yanpan; Zhang, Zicheng; Zhang, Jiande; Liu, Zhuofeng; Song, Zuyin

    2015-05-01

    As an alternative to water, propylene carbonate (PC) has a good application prospect in the compact pulsed power sources for its breakdown strength higher than that of water, resistivity bigger than 109 Ω m, and low freezing temperature (-49 °C). In this paper, the investigation into dielectric breakdown of PC and PC-based nano-fluids (NFs) subjected to high amplitude electric field is presented with microsecond pulses applied to a 1 mm gap full of PC or NFs between spherical electrodes. One kind of NF is composed of PC mixed with 0.5-1.4 vol. % BaTiO3 (BT) nano-particles of mean diameter ≈100 nm and another is mixed with 0.3-0.8 vol. % BT nano-particles of mean diameter ≈30 nm. The experimental results demonstrate the rise of permittivity and improvement of the breakdown strength of NFs compared with PC. Moreover, it is found that there exists an optimum fraction for these NFs corresponding to tremendous surface area in nano-composites with finite mesoscopic thickness. In concrete, the dielectric breakdown voltage of NFs is 33% higher than that of PC as the volume concentration of nano-particles with a 100 nm diameter is 0.9% and the breakdown voltage of NFs is 40% higher as the volume concentration of nano-particles with a 30 nm diameter is 0.6%. These phenomena are considered as the dielectric breakdown voltage of PC-based NFs is increased because the interfaces between nano-fillers and PC matrices provide myriad trap sites for charge carriers, which play a dominant role in the breakdown performance of NFs.

  4. Controlled structural and optical properties of ZnO nano-particles

    Kazemi, Asieh Sadat; Ketabi, Seyed Ahmad [School of Physics and Center for Solid State Research, Damghan University, Damghan (Iran, Islamic Republic of); Abadyan, Mohamadreza, E-mail: abadyan@yahoo.co [Mechanical Engineering Group, Islamic Azad University, Tonekabon Branch, Ramsar Center (Iran, Islamic Republic of)

    2010-09-15

    In this work, we have analyzed two synthesis procedures through experimental characterizations, where one provides a main temperature region for the control of the shape and size of ZnO nano-particles in comparison to the other. We have found that the complexing agent has a significant role in showing such a control region. This effect might also improve the fabrication and properties of other interesting and applicable nano-structures.

  5. Experimental study of combustion of decane, dodecane and hexadecane with polymeric and nano-particle additives

    Ghamari, Mohsen; Ratner, Albert

    2015-11-01

    Recent studies have shown that adding combustible nano-particles could have promising effects on increasing burning rate of liquid fuels. Combustible nano-particles could enhance the heat conduction and mixing within the droplet. Polymers have also higher burning rate than regular hydrocarbon fuels because of having the flame closer to the droplet surface. Therefore adding polymeric additive could have the potential to increase the burning rate. In this study, combustion of stationary fuel droplets of n-Decane, n-Dodecane and n-Hexadecane doped with different percentages of a long chain polymer and also a very fine nano carbon was examined and compared with the pure hydrocarbon behavior. In contrast with hydrocarbon droplets with no polymer addition, several zones of combustion including a slow and steady burning zone, a strong swelling zone and a final fast and fairly steady combustion zone were also detected. In addition, increasing polymer percentage resulted in a more extended swelling zone and shorter slow burning zone in addition to a shorter total burning time. Addition of nano-particles also resulted in an overall increased burning rate and shortened burning time which is due to enhanced heat conduction within the droplet.

  6. Agglomerated polymer monoliths with bimetallic nano-particles as flow-through micro-reactors

    Polymer monoliths in capillary format have been prepared as solid supports for the immobilisation of platinum/palladium bimetallic nano-flowers. Optimum surface coverage of nano-flowers was realised by photografting the monoliths with vinyl azlactone followed by amination with ethylenediamine prior to nano-particle immobilisation. Field emission SEM imaging was used as a characterisation tool for evaluating nano-particle coverage, together with BET surface area analysis to probe the effect of nano-particle immobilisation upon monolith morphology. Ion exchange chromatography was also used to confirm the nature of the covalent attachment of nano-flowers on the monolithic surface. In addition, EDX and ICP analyses were used to quantify platinum and palladium on modified polymer monoliths. Finally the catalytic properties of immobilised bimetallic Pd/Pt nano-flowers were evaluated in flow-through mode, exploiting the porous interconnected flow-paths present in the prepared monoliths (pore diameter ∼ 1-2 μm). Specifically, the reduction of Fe (III) to Fe (II) and the oxidation of NADH to NAD+ were selected as model redox reactions. The use of a porous polymer monolith as an immobilisation substrate (rather than aminated micro-spheres) eliminated the need for a centrifugation step after the reaction. (author)

  7. Effects of Natural Organic Matter on Stability, Transport and Deposition of Engineered Nano-particles in Porous Media

    The interaction of nano-particles and organic substances, like natural organic matter, could have significant influence on the fate, transport and bioavailability of toxic substances. Natural organic matter (NOM) is a mixture of chemically complex polyelectrolytes with varying m...

  8. The effect of acid–base clustering and ions on the growth of atmospheric nano-particles

    Lehtipalo, Katrianne; Rondo, Linda; Kontkanen, Jenni; Schobesberger, Siegfried; Jokinen, Tuija; Sarnela, Nina; Kürten, Andreas; Ehrhart, Sebastian; Franchin, Alessandro; Nieminen, Tuomo; Riccobono, Francesco; Sipilä, Mikko; Yli-Juuti, Taina; Duplissy, Jonathan; Adamov, Alexey

    2016-01-01

    The growth of freshly formed aerosol particles can be the bottleneck in their survival to cloud condensation nuclei. It is therefore crucial to understand how particles grow in the atmosphere. Insufficient experimental data has impeded a profound understanding of nano-particle growth under atmospheric conditions. Here we study nano-particle growth in the CLOUD (Cosmics Leaving OUtdoors Droplets) chamber, starting from the formation of molecular clusters. We present measured growth rates at su...

  9. Airflow structures and nano-particle deposition in a human upper airway model

    Considering a human upper airway model, or equivalently complex internal flow conduits, the transport and deposition of nano-particles in the 1-150 nm diameter range are simulated and analyzed for cyclic and steady flow conditions. Specifically, using a commercial finite-volume software with user-supplied programs as a solver, the Euler-Euler approach for the fluid-particle dynamics is employed with a low-Reynolds-number k-ω model for laminar-to-turbulent airflow and the mass transfer equation for dispersion of nano-particles or vapors. Presently, the upper respiratory system consists of two connected segments of a simplified human cast replica, i.e., the oral airways from the mouth to the trachea (Generation G0) and an upper tracheobronchial tree model of G0-G3. Experimentally validated computational fluid-particle dynamics results show the following: (i) transient effects in the oral airways appear most prominently during the decelerating phase of the inspiratory cycle; (ii) selecting matching flow rates, total deposition fractions of nano-size particles for cyclic inspiratory flow are not significantly different from those for steady flow; (iii) turbulent fluctuations which occur after the throat can persist downstream to at least Generation G3 at medium and high inspiratory flow rates (i.e., Qin≥30 l/min) due to the enhancement of flow instabilities just upstream of the flow dividers; however, the effects of turbulent fluctuations on nano-particle deposition are quite minor in the human upper airways; (iv) deposition of nano-particles occurs to a relatively greater extent around the carinal ridges when compared to the straight tubular segments in the bronchial airways; (v) deposition distributions of nano-particles vary with airway segment, particle size, and inhalation flow rate, where the local deposition is more uniformly distributed for large-size particles (say, dp=100 nm) than for small-size particles (say, dp=1 nm); (vi) dilute 1 nm particle

  10. Boundary lubrication by nano-particles; Lubrification limite par les nanoparticules

    Cizaire, L.

    2003-09-15

    The replacement of aggressive organic molecules by mineral particles which could reduce friction and wear has been the main idea of this research work. The aim is thus to reduce product concentration in lubricant and pollutant gas emission. Boundary lubrication regime is well suited for this type of study in particular for being discriminative in tested nano-particles efficacy. We are firstly being interested in an anti-wear additive. A physical and chemical study of dialysed over based calcium sulfonates by EFTEM, XPS and ToF-SIMS lead to describe nano-particles as calcium carbonate core, still amorphous by the residual presence of calcium hydroxide and surrounded by di-dodecyl-benzene sulfonate surfactant chains. Their anti-wear action has been investigated by coupling many tribo-meters with different contact geometry. Rubbing surfaces were protected by a thick tribo-film being on surfaces without any scratches. When additive is in contact area under high pressure and shearing, micellar structure is broken. Hydro-carbonated chains initially control friction by being broken up and then with increasing of contact severity, sulfonate chains are expulsed out of the tribo-film. Tribo-film growth corresponds then to agglomeration and crystallization of calcium carbonate core striped of detergent chains. We have shown then friction reduction capabilities of inorganic-fullerene (IF) MoS{sub 2} nano-particles. Lubricating power of MoS{sub 2} layers is as good whatever the layers number leading thinking that friction value is intrinsic character of compound nature. Fullerene nano-particles were described by HR-TEM as a concentric and closed multi-layered structure. Coupling of Raman, XRD and EXAFS have shown that MoS{sub 2} layers were well organised in hexagonal form with distortion in Mo-Mo bonds reaching 1% of initial length. Chemical stability of such structure, in particular in regard of oxidation, is very impressive. XPS, XANES and ToF-SIMS analyses have lead to

  11. Nano-particle precipitation in mechanically alloyed and annealed precursor powders of legacy PM2000 ODS alloy

    Highlights: • Nano-particle formation identified in Plansee PM2000 ODS alloy powders. • Y–Al–O nano-particles observed after annealing at 923 K for 5 h. • Particle diameter ≈2 nm and NV > 1023 m−3 over annealing range 1123–1223 K. • Particles dissolved at, and reprecipitated behind, recrystallisation fronts. - Abstract: The early stages of nano-particulate formation in mechanically alloyed and annealed, precursor powders used to manufacture the legacy commercial oxide dispersion strengthened alloy PM2000, formerly produced by Plansee GmbH, have been investigated. Powders were analysed in both the as-mechanically-alloyed condition and after annealing over the temperature range 923–1423 K. The nucleation and growth of coherent nano-particles in the partially recovered, fine grained, ferritic matrix of powders annealed at temperatures as low as 923 K has been confirmed. Powders annealed for 1 h at temperatures of 1123 K and 1223 K were partially recrystallised and contained high number densities (NV > 1023 m−3) of coherent 2 nm yttrium–aluminium–oxygen rich nano-particles. The identification of particle free zones in recrystallised grains, adjacent to recrystallising interfaces, plus the identical orientation relationships between nano-particles and the matrices in both unrecrystallised and recrystallised grains, indicates that the Y–Al–O nano-particles, first formed in fine grained regions, are dissolved during recrystallisation and re-precipitated subsequently in recrystallised grains

  12. Doping of TiO2 nano-particles in Y 123 superconductor

    Full text: In order to improve transport properties of superconductors, there have been lots of efforts like doping, irradiation, and heat treatment. There are a few reports about doping of nano-particles in high temperature superconductors. In this work we have doped TiO2 nano-particles in YBa2Cu3O7-d (Y 123) which was made by solid state method. We have prepared samples with two synthesis processes; Four samples which will be referred as 'standard' were prepared with doping of TiO2 nano-particles with 0, 3, 6, and 9 %wt to calcined (Oxygen uncompleted) Y 123 sample. The other samples named 'reference' were prepared with doping of TiO2 nano-particles with 0, 3, 6, and 9 % wt to sintered (Oxygen completed) Y 123 sample. These samples were annealed at 450 oC for one hour. In the standard samples, due to high temperature process, there is a probability of chemical reaction of TiO2 nano-particles with Y 123. So, the annealing temperature of the reference samples was chosen low such that TiO2 and Y 123 do not react with each other. Some measurements like XRD, SEM, R(T), Meissner effect, magnetic susceptibility, and I-V were performed. The XRD patterns showed the existence of YBa3Ti2O8.5 impurity phase and the intense increase of it with doping in the standard samples, consisted with susceptibility experiments. The XRD experiment in the reference samples confirmed the existence of TiO2 phase without any reaction with Y 123. In the SEM images of the standard samples some areas with different contrasts were observed, which seems to be the impurity secondary phase. In addition, in the SEM images of the reference samples, nano-metric particles (TiO2) beside micro-metric particles (Y 123) were observed. This means that TiO2 nano-particles have no any reaction with Y 123 phase, which is in agreement with XRD analysis. The Meissner effect for pure standard sample and all the reference samples was observed. The results of R(T) showed that just pure standard sample (Std 0 %) has

  13. Heat transfer augmentation of a circular pipe flow using nano-particle layers

    Yamagishi, Akira; Yuki, Kazuhisa; Sato, Tomoaki; Hashizume, Hidetoshi [Tohoku Univ. (Japan). Dept. of Quantum Science and Energy Engineering; Kunugi, Tomoaki [Kyoto Univ. (Japan). Faculty of Engineering; Sagara, Akio [National Inst. for Fusion Science (Japan)

    2007-07-01

    For the advanced fusion reactor FFHR2 (Force Free Helical Reactor) that has been proposed by NIFS, molten salt Flibe (LiF:BeF2=64:36) breeder blanket system is selected because of Flibe's features such as chemical stability, low-pressure operation and low electric conductivity. The Flibe is however high Prandtl number fluid since it has high viscosity and low thermal conductivity. Therefore its heat transfer performance is low compared with liquid Li or Pb-Li. In addition to heat removal of 1MW/m2 on the first wall, electrolysis of molten salt due to MHD effect will take place under high flow rate condition. This indicates that heat transfer enhancement under low flow rate is essential for the Flibe blanket system. In our laboratory, heat transfer characteristics of molten salt HTS (KNO3:NaNO2:NaNO3=53:40:7), have been evaluated, which is used as a simulant fluid of Flibe from the points of view of Be's toxicity and similar Prandtl number. In this paper, we adopt nano-particle layer method to form nano{proportional_to}micro scale structure on a heating surface using an acid or an alkali includes nano particles. There exist two methods to form nano particle layer. One is NPLS (Nano Particle Layer Structure) method which uses a chemical etching with an acid or an alkali including copper-oxide nano-particles. The other is FP (Fine Particle) method which employs electroless plating with inorganic metal salt solution. At first, immersion experiments of NPLS or FP layers into melted HTS shows that erosion of the FP sample is much less than that of the NPLS sample. Furthermore, a forced-convention heat transfer experiments with a circular tube whose inner surface has the nano-particle layer by the FP method is carried out in a large molten salt circulating loop named as TNT loop. Results show that average Nusselt numbers of the circular tube flow are about 1.3 times higher than that of a bared tube in the range of 3000

  14. Synthesis and characterization of β-phase iron silicide nano-particles by chemical reduction

    Graphical abstract: - Highlights: • β-FeSi2 nano-particle was synthesized by reducing with Mg and by diluting with MgO. • XRD profile shows the iron di-silicide phase to be semiconducting β-FeSi2. • HRTEM and FESEM images indicate the β-FeSi2average particle size to be 60–70 nm. • Absorption, reflectance and PL spectroscopy show band gap to be direct 0.87 eV. • Nano-β-FeSi2is p-type with hole density of 4.38 × 1018 cm−3 and mobility 8.9 cm2/V s. - Abstract: Nano-particles of β-FeSi2 have been synthesized by chemical reduction of a glassy phase of [Fe2O3, 4SiO2] by Mg-metal where MgO is used as diluent to prevent the agglomeration of nano crystallites into micro-particles and also act as a negative catalyst for the formation of other phases. The sample is characterized by XRD, FESEM, HRTEM, EDX, ultra-violet-visible-infrared and PL spectroscopy and electronic properties have been investigated by Hall measurement. XRD profile shows that the synthesized powder consists of purely β-FeSi2 semiconducting phase. The average crystallite size of β-FeSi2 is determined to be around 65.4 nm from XRD peaks as well as from FESEM also. The optical absorption and PL spectroscopy shows that synthesized β-FeSi2 phase is a direct band gap semiconductor with a value of 0.87 eV. Hall measurements show that β-FeSi2 nano-particles is p-type with hole concentration of 4.38 × 1018 cm−3 and average hole mobility of 8.9 cm2/V s at 300 K

  15. Detection of biocolloids in aquatic media by Nano-Particle Analyzer

    Bundschuh, T.; T. Wagner; Eberhagen, I.; Hambsch, B.; KÖster, R.

    2005-01-01

    The Nano-Particle Analyzer (NPA) based on Laser-Induced Breakdown Detection (LIBD) selectively generates and detects plasma events on colloids in aquatic media. Here, it is made use of the fact that the power density required for plasma generation decreases from the gaseous to the solid medium. At an adequate laser pulse energy, plasmas can thus be generated selectively on colloids. The detections of biocolloids by LIBD-based NPA as described in this paper for the first time clearly reveal th...

  16. Size dependence of vacancy migration energy in ionic nano particles: A potential energy landscape perspective

    Niiyama, Tomoaki; Okushima, Teruaki; Ikeda, Kensuke S.; Shimizu, Yasushi

    2016-06-01

    Size dependence of vacancy migration energy in ionic nano particles is investigated by analysis of potential energy surfaces in potassium chloride clusters. Numerical methods are used to find almost all local minima and transition states for vacancy migration in clusters of different sizes, and reveal characteristic features of energy surface structure. It is shown that migration energy is significantly lower near a cluster surface than near a cluster core, and the mean first-passage time for migration of a vacancy decreases with cluster size. These results are consistent with observations of high diffusion rates in small clusters.

  17. Nano-particles produced by a simple formula; Nanoteilchen nach einfacher Rezeptur

    Wengenmayr, R.

    2001-07-01

    Nano-particles for fuel cell catalysts with a dimater of a few billionth parts of a meter can be produced by a simple, low-cost and environment-friendly method developed by a working group headed by Manfred T. Reetz, Director of the Max-Planck Institute of Coal Research at Muelheim on the Ruhr. [German] 'Nanopartikel' fuer Brennstoffzellen-Katalysatoren mit einem Durchmesser von wenigen Milliardstel Metern koennen neuerdings erstaunlich einfach, preiswert und umweltfreundlich hergestellt werden. Entwickelt wurde das Verfahren von der Arbeitsgruppe um Manfred T. Reetz, Direktor am Max-Planck-Institut fuer Kohlenforschung in Muelheim an der Ruhr. (orig.)

  18. Direct large-scale synthesis of perovskite barium strontium titanate nano-particles from solutions

    This paper reports a wet chemical synthesis technique for large-scale fabrication of perovskite barium strontium titanate nano-particles near room temperature and under ambient pressure. The process employs titanium alkoxide and alkali earth hydroxides as starting materials and involves very simple operation steps. Particle size and crystallinity of the particles are controllable by changing the processing parameters. Observations by X-ray diffraction, scanning electron microscopy and transmission electron microscopy TEM indicate that the particles are well-crystallized, chemically stoichiometric and ∼50nm in diameter. The nanoparticles can be sintered into ceramics at 1150 deg. C and show typical ferroelectric hysteresis loops

  19. Mobilization and biodegradation of 2-methylnaphthalene by amphiphilic polyurethane nano-particle.

    Kim, Young-Bum; Kim, Ju-Young; Kim, Eun-ki

    2009-10-01

    Amphiphilic polyurethane (APU) nano-particle enhanced the mobilization of 2-methylnaphthalene (2-MNPT) in soil. Significant increase in the solubility of 2-MNPT was achieved. The molar solubilization ratio was 0.4 (mole 2-MNPT/mole APU). Simple precipitation of APU particle by 2 N CaCl(2) recovered 95% of APU particle and 92% of 2-MNPT simultaneously. Also, 2-MNPT, which was entrapped inside the APU particle, was directly degraded by Acinetobacter sp. as same efficiency as without APU particle. These results showed the potentials of APU particle in the mobilization and biodegradation of hydrophobic compounds from soil. PMID:19214790

  20. Fabrication and characterisation of gold nano-particle modified polymer monoliths for flow-through catalytic reactions and their application in the reduction of hexacyanoferrate

    Polymer monoliths in capillary (100 μm i.d.) and polypropylene pipette tip formats (vol: 20 μL) were modified with gold nano-particles (AuNP) and subsequently used for flow-through catalytic reactions. Specifically, methacrylate monoliths were modified with amine-reactive monomers using a two-step photografting method and then reacted with ethylenediamine to provide amine attachment sites for the subsequent immobilisation of 4 nm, 7 nm or 16 nm AuNP. This was achieved by flushing colloidal suspensions of gold nano-particles through each aminated polymer monolith which resulted in a multi-point covalent attachment of gold via the lone pair of electrons on the nitrogen of the free amine groups. Field emission scanning electron microscopy and scanning capacitively coupled conductivity detection was used to characterise the surface coverage of AuNP on the monoliths. The catalytic activity of AuNP immobilised on the polymer monoliths in both formats was then demonstrated using the reduction of Fe(III) to Fe(II) by sodium borohydride as a model reaction by monitoring the reduction in absorbance of the hexacyanoferrate (III) complex at 420 nm. Catalytic activity was significantly enhanced on monoliths modified with smaller AuNP with almost complete reduction (95 %) observed when using monoliths agglomerated with 7 nm AuNPs. (author)

  1. Synthesis and characterization of nano ZnO, nano Ag/ZnO composite & nano-particles embedded polymers

    Are, Thilak Reddy

    Zinc oxide and silver/zinc oxide nano particles were synthesized by a simple precipitation method in the presence of polyvinylpyrrolidone (PVP). The presence of polyvinylpyrrolidone prevents agglomeration and allows the formation of nano sized particles. Characterization of synthesized nano particles were carried out using X-ray powder diffraction, differential scanning calorimetry, scanning electron microscopy, and the average sizes were determined by zeta seizer. The X-ray diffraction shows that the prepared particles were poorly crystalline. The DSC results show that the prepared particles are highly stable and no phase changes were observed when heated from room temperature to 500°C. Scanning electron microscopic observation shows that the particles are uniformly distributed with similar shape. Zeta seizer results show that the prepared particles are nano-particles with average size of about 100 nm. The prepared Zinc oxide nano particles were embedded into the polycaprolactone (PCL) polymer to study the effect of embedding zinc oxide nanoparticle on PCL crystallinity and mechanical properties. ZnO nano particles were successfully embedded into the polymer using in-situ and non-in-situ embedding processes. Characterization of PCL embedded with ZnO nanoparticles was performed by X-ray diffraction technique and scanning electron microscope. Crystallinity studies were done by using differential scanning calorimetry and the results show that the polymer embedded using an in situ process showed a decrease in crystallinity compared to the polymer embedded using a non-insitu process.

  2. Electrical conductivity modification using silver nano particles of Jatropha Multifida L. and Pterocarpus Indicus w. extracts films

    Diantoro, Markus; Hidayati, Nisfi Nahari Sani; Latifah, Rodatul; Fuad, Abdulloh; Nasikhudin, Sujito, Hidayat, Arif

    2016-03-01

    Natural polymers can be extracted from leaf or stem of plants. Pterocarpus Indicus W. (PIW) and Jatropha Multifida L. (JIL) plants are good candidate as natural polymer sources. PIW and JIW polymers contain chemical compound so-called flavonoids which has C6-C3-C6 carbons conjugated configuration. The renewable type of polymer as well as their abundancy of flavonoid provide us to explore their physical properties. A number of research have been reported related to broad synthesis method and mechanical properties. So far there is no specific report of electrical conductivity associated to PIW and JIL natural polymers. In order to obtain electrical conductivity and its crystallinity of the extracted polymer films, it was induced on them a various fraction of silver nano particles. The film has been prepared by means of spin coating method on nickel substrate. It was revealed that FTIR spectra confirm the existing of rutine flavonoid. The crystallinity of the samples increase from 0.66%, to 4.11% associated to the respective various of silver fractions of 0.1 M to 0.5 M. SEM images show that there are some grains of silver in the film. The nature of electric conductivity increases a long with the addition of silver. The electrical conductivity increase significantly from 3.22 S/cm, to 542.85 S/cm. On the other hand, PIW films also shows similar trends that increase of Ag induce the increase its crystallinity as well as its electrical conductivity at semiconducting level. This result opens a prospective research and application of the green renewable polymer as optoelectronic materials.

  3. Development of Single-side Magnet Array for Super Paramagnetic Nano-particle Targeting

    Wei He

    2014-04-01

    Full Text Available Permanent magnets are interesting for the use in magnetic drug targeting devices. The magnetic fields and forces with distances from magnets have limited the depth of targeting. Producing greater forces at deep depth by optimally designed magnet arrays would allow treatment of a wider class of patients. In this study, we present a design of a permanent magnet array for deep magnetic capture of super paramagnetic iron oxide nano-particles, which consists of an array of 3 individual bar permanent magnet positioned to achieve a reasonably magnitude magnetic field and its gradient within a deeply region. These configurations were simulated with two-dimensional finite-element methods. The super paramagnetic iron oxide nano-particles were adopted Fe3O4 particles with diameter 40 nm by chemical co-precipitation method. Performance factors were defined to relate magnetic field force with mass. The field strength and gradient were measured by a Hall probe and agreed well with the simulations.

  4. Combined DFT/FTIR structural studies of monodispersed PVP/Gold and silver nano particles

    Abdelghany, A.M., E-mail: a.m_abdelghany@yahoo.com [Spectroscopy Department, Physics Division, National Research Center, Dokki, 12311, Cairo (Egypt); Mekhail, M.Sh.; Abdelrazek, E.M.; Aboud, M.M. [Physics Department, Faculty of Science, Mansoura University, 35516, Mansoura (Egypt)

    2015-10-15

    Nano-particles of two Nobel metals, namely, (silver and gold) were prepared and used as a dopant in polyvinyl pyrrolidone (PVP) polymeric matrix by the simple casting technique. Prepared samples examined theoretically using density functional theory (DFT) and experimentally with Fourier transform infrared (FTIR) and (UV/Vis) spectroscopy. DFT calculations and FTIR experimental results shows the persistence of the characteristic bands of polymeric network in their positions while pyrrolidinone adsorbed both silver and gold colloid surfaces preferably via the non-bonding electrons of the carbonyl group. UV/Vis experimental data was employed to calculate the optical energy gap of pristine and doped samples. Optical band gap and particle size were calculated and is in agreement with the results obtained from TEM data. Transmission electron microscopy shows that the prepared silver and gold nanoparticles were mono dispersed within the polymeric matrix. - Highlights: • Nano-particles of two Nobel metals, namely, (silver and gold) were prepared. • Polyvinyl pyrrolidone polymeric matrix doped with nobel metal were prepared via casting technique. • Prepared samples investigated via combined (DFT) and (FTIR). • Transmission electron microscopy shows monodispersed nanoparticles.

  5. Analytical Investigation of Jeffery-Hamel Flow with High Magnetic Field and Nano Particle by RVIM

    Many researchers have been interested in application of mathematical methods to find analytical solutions of nonlinear equations and for this purpose, new methods have been developed. One of the newest analytical methods to solve nonlinear equations is Reconstruction of variational Iteration Method which is an accurate and a rapid convergence method in finding the approximate solution for nonlinear equations. By applying Laplace Transform, Reconstruction of variational Iteration Method overcomes the difficulty of the perturbation techniques and other variational methods in case of using small parameters and Lagrange multipliers, respectively. In this study Reconstruction of variational Iteration Method is applied for the effects of magnetic field and nano particle on the Jeffery-Hamel flow. The traditional Navier-Stokes equation of fluid mechanics and Maxwell's electromagnetism governing equations are reduced to nonlinear ordinary differential equations to model the problem. The flow field inside the divergent channel is studied for various values of Hartmann number and angle of channel. Finally the effect of nano particle volume fraction in the absence of magnetic field is investigated, too. The validity of Reconstruction of variational Iteration Method method is ascertained by comparing our results with numerical (Runge Kutta method) results.

  6. Combined DFT/FTIR structural studies of monodispersed PVP/Gold and silver nano particles

    Nano-particles of two Nobel metals, namely, (silver and gold) were prepared and used as a dopant in polyvinyl pyrrolidone (PVP) polymeric matrix by the simple casting technique. Prepared samples examined theoretically using density functional theory (DFT) and experimentally with Fourier transform infrared (FTIR) and (UV/Vis) spectroscopy. DFT calculations and FTIR experimental results shows the persistence of the characteristic bands of polymeric network in their positions while pyrrolidinone adsorbed both silver and gold colloid surfaces preferably via the non-bonding electrons of the carbonyl group. UV/Vis experimental data was employed to calculate the optical energy gap of pristine and doped samples. Optical band gap and particle size were calculated and is in agreement with the results obtained from TEM data. Transmission electron microscopy shows that the prepared silver and gold nanoparticles were mono dispersed within the polymeric matrix. - Highlights: • Nano-particles of two Nobel metals, namely, (silver and gold) were prepared. • Polyvinyl pyrrolidone polymeric matrix doped with nobel metal were prepared via casting technique. • Prepared samples investigated via combined (DFT) and (FTIR). • Transmission electron microscopy shows monodispersed nanoparticles

  7. Preparation and Characterization of Fe3O4 Magnetic Nano-particles by 60Co γ-ray Irradiation

    Mingcheng YANG; Hongyan SONG; Chengshen ZHU; Suqin HE; Ya GAO

    2007-01-01

    By using a new method, 60C0 γ-ray irradiation, Fe3O4 magnetic nano-particles were successfully synthesized at room temperature under ambient pressure. The structure, morphology and magnetic properties of these nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM), respectively. The radiation formation mechanism was also discussed. The results show that the absorbed dose can greatly influence the structure, morphology and magnetic properties of the products. XRD and TEM studies show that the product prepared by γ-ray irradiation (10 kGy) is pure FesO4 phase and the mean diameter of these nano-particles is about 21 nm. The Fe3O4 nano-particles synthesized by γ-ray irradiation (10 kGy) are mainly in small cubic shape and the size uniformity of these particles is good.

  8. Synthesis of SmOHCO3 micro/nano particles from the coupling route of homogeneous precipitation with microemulsion

    朱文庆; 瞿芳; 陈浩军; 李卓; 刘斌

    2014-01-01

    SmOHCO3micro/nano particles were prepared in water/oil (W/O) reverse microemulsion composed of cetyltrimethyl ammonium bromide (CTAB), n-octane, n-butanol, Sm(NO3)3·6H2O and urea aqueous solution by the coupling route of homogeneous precipitation with microemulsion. The nanoparticles were characterized and analyzed by X-ray powder diffraction (XRD), thermal gravimetric and differential thermal gravimetric analysis (TG-DTG), Fourier transform infrared absorption spectra (FT-IR) and scan-ning electron microscope (SEM). The results showed that the phase SmOHCO3 micro/nano particles was in agreement with pure or-thorhombic phase. The different morphologies of SmOHCO3 micro/nano particles with good monodispersity and size were obtained by regulating the reaction temperature and reaction time. Possible formation mechanisms of the morphological structure of SmO-HCO3 were proposed and discussed.

  9. Nano-particle precipitation in mechanically alloyed and annealed precursor powders of legacy PM2000 ODS alloy

    Dawson, Karl, E-mail: k.dawson@liverpool.ac.uk [Centre for Materials and Structures, School of Engineering, University of Liverpool, L69 3GH (United Kingdom); Haigh, Sarah J. [School of Materials, Materials Science Centre, University of Manchester, M13 9PL (United Kingdom); Tatlock, Gordon J.; Jones, Andy R. [Centre for Materials and Structures, School of Engineering, University of Liverpool, L69 3GH (United Kingdom)

    2015-09-15

    Highlights: • Nano-particle formation identified in Plansee PM2000 ODS alloy powders. • Y–Al–O nano-particles observed after annealing at 923 K for 5 h. • Particle diameter ≈2 nm and N{sub V} > 10{sup 23} m{sup −3} over annealing range 1123–1223 K. • Particles dissolved at, and reprecipitated behind, recrystallisation fronts. - Abstract: The early stages of nano-particulate formation in mechanically alloyed and annealed, precursor powders used to manufacture the legacy commercial oxide dispersion strengthened alloy PM2000, formerly produced by Plansee GmbH, have been investigated. Powders were analysed in both the as-mechanically-alloyed condition and after annealing over the temperature range 923–1423 K. The nucleation and growth of coherent nano-particles in the partially recovered, fine grained, ferritic matrix of powders annealed at temperatures as low as 923 K has been confirmed. Powders annealed for 1 h at temperatures of 1123 K and 1223 K were partially recrystallised and contained high number densities (N{sub V} > 10{sup 23} m{sup −3}) of coherent 2 nm yttrium–aluminium–oxygen rich nano-particles. The identification of particle free zones in recrystallised grains, adjacent to recrystallising interfaces, plus the identical orientation relationships between nano-particles and the matrices in both unrecrystallised and recrystallised grains, indicates that the Y–Al–O nano-particles, first formed in fine grained regions, are dissolved during recrystallisation and re-precipitated subsequently in recrystallised grains.

  10. Support vector machine to predict diesel engine performance and emission parameters fueled with nano-particles additive to diesel fuel

    Ghanbari, M.; Najafi, G.; Ghobadian, B.; Mamat, R.; Noor, M. M.; Moosavian, A.

    2015-12-01

    This paper studies the use of adaptive Support Vector Machine (SVM) to predict the performance parameters and exhaust emissions of a diesel engine operating on nanodiesel blended fuels. In order to predict the engine parameters, the whole experimental data were randomly divided into training and testing data. For SVM modelling, different values for radial basis function (RBF) kernel width and penalty parameters (C) were considered and the optimum values were then found. The results demonstrate that SVM is capable of predicting the diesel engine performance and emissions. In the experimental step, Carbon nano tubes (CNT) (40, 80 and 120 ppm) and nano silver particles (40, 80 and 120 ppm) with nanostructure were prepared and added as additive to the diesel fuel. Six cylinders, four-stroke diesel engine was fuelled with these new blended fuels and operated at different engine speeds. Experimental test results indicated the fact that adding nano particles to diesel fuel, increased diesel engine power and torque output. For nano-diesel it was found that the brake specific fuel consumption (bsfc) was decreased compared to the net diesel fuel. The results proved that with increase of nano particles concentrations (from 40 ppm to 120 ppm) in diesel fuel, CO2 emission increased. CO emission in diesel fuel with nano-particles was lower significantly compared to pure diesel fuel. UHC emission with silver nano-diesel blended fuel decreased while with fuels that contains CNT nano particles increased. The trend of NOx emission was inverse compared to the UHC emission. With adding nano particles to the blended fuels, NOx increased compared to the net diesel fuel. The tests revealed that silver & CNT nano particles can be used as additive in diesel fuel to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

  11. Synthesis and characterization of β-phase iron silicide nano-particles by chemical reduction

    Sen, Sabyasachi [Department of Electronics & Electrical Communication Engineering, Indian Institute of Technology, Kharagpur 721302 (India); Gogurla, Narendar [Department of Physics, Indian Institute of Technology, Kharagpur 721302 (India); Banerji, Pallab [Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India); Guha, Prasanta K. [Department of Electronics & Electrical Communication Engineering, Indian Institute of Technology, Kharagpur 721302 (India); Pramanik, Panchanan, E-mail: pramanik1946@gmail.com [Department of Basic Science, MCKV Institute of Engineering, Howrah, Liluah 711204 (India)

    2015-10-15

    Graphical abstract: - Highlights: • β-FeSi{sub 2} nano-particle was synthesized by reducing with Mg and by diluting with MgO. • XRD profile shows the iron di-silicide phase to be semiconducting β-FeSi{sub 2}. • HRTEM and FESEM images indicate the β-FeSi{sub 2}average particle size to be 60–70 nm. • Absorption, reflectance and PL spectroscopy show band gap to be direct 0.87 eV. • Nano-β-FeSi{sub 2}is p-type with hole density of 4.38 × 10{sup 18} cm{sup −3} and mobility 8.9 cm{sup 2}/V s. - Abstract: Nano-particles of β-FeSi{sub 2} have been synthesized by chemical reduction of a glassy phase of [Fe{sub 2}O{sub 3}, 4SiO{sub 2}] by Mg-metal where MgO is used as diluent to prevent the agglomeration of nano crystallites into micro-particles and also act as a negative catalyst for the formation of other phases. The sample is characterized by XRD, FESEM, HRTEM, EDX, ultra-violet-visible-infrared and PL spectroscopy and electronic properties have been investigated by Hall measurement. XRD profile shows that the synthesized powder consists of purely β-FeSi{sub 2} semiconducting phase. The average crystallite size of β-FeSi{sub 2} is determined to be around 65.4 nm from XRD peaks as well as from FESEM also. The optical absorption and PL spectroscopy shows that synthesized β-FeSi{sub 2} phase is a direct band gap semiconductor with a value of 0.87 eV. Hall measurements show that β-FeSi{sub 2} nano-particles is p-type with hole concentration of 4.38 × 10{sup 18} cm{sup −3} and average hole mobility of 8.9 cm{sup 2}/V s at 300 K.

  12. Enhancing Asphalt Binder's Rheological Behavior and Aging Susceptibility Using Nano-Particles

    Walters, Renaldo C.

    The life expectancy of Asphalt Binder (AB) has been negatively impacted by the harsh bombardment of UV rays. UV rays cause asphalt to oxidize faster which results in deterioration of asphalt rheological characteristics that can lead to pavement distresses. This study investigates the impact that nano-particles and bio modification have on the aging susceptibility of asphalt binder. As such, the following hypothesis was investigated: Introduction of nano particles to asphalt binder will reduce asphalt oxidation aging by increasing the inter layer spacing of the nano particles. Two nano scale materials were used for this study, nano-clay and bio-char as well as one micro scale material, silica fume. Nano-clay (Cloisite 30B) is a naturally occurring inorganic mineral. Bio-char is the waste product from bio-binder production. Bio-binder is produced from swine manure using a thermochemical conversion process. This process is then followed by a filtration procedure where the bio-char is produced. Chemical and physical properties of bio-char showed a significant presence of carbon which could in turn reduce the rate of asphalt oxidation. Silica Fume is an ultra-fine powder collected as a by-product of silicon and ferrosilicon alloy production and consists of spherical particles. In this study several mixtures are designed and evaluated using RV testing (Rotational Viscometer), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Nano-clay is blended at 2% and 4% by weight of dry mass, with and without bio-binder (5% by weight of dry mass). Bio-char is grinded to nano scale and added to the virgin asphalt binder (PG 64-22) at 2%, 5% and 10% by weight of dry mass. Silica Fume is added to virgin asphalt binder (PG 64-22) at 2%, 4% and 8% by weight of dry mass. The optimum percent of nano scale material that is added to virgin asphalt binder is expected to reduce aging susceptibility of asphalt binder, extending its service life.

  13. Seed Coat Permeability of Active Ingredients

    Niemann, Sylvia

    2013-01-01

    The seed coat is the barrier controlling exchange of solutes between the plant embryo and its environment. This exchange is of importance for example in the uptake of germination inhibitors or in the uptake of agrochemicals applied as seed treatment. A thorough understanding of the basic mechanisms underlying solute permeation across the seed coat would help to improve the effectiveness of seed treatment formulations. In seed treatment formulations, additives can be used to enhance or decreas...

  14. Influence of fuel ratios on auto combustion synthesis of barium ferrite nano particles

    D Bahadur; S Rajakumar; Ankit Kumar

    2006-01-01

    Single-domain barium ferrite nano particles have been synthesized with narrow particle-size distribution using an auto combustion technique. In this process, citric acid was used as a fuel. Ratios of cation to fuel were maintained variously at 1 : 1, 1 : 2 and 1 : 3. The pH was 7 in all cases. Of all three cases, a cation to citric acid ratio of 1 : 2 gives better yield in the formation of crystalline and single domain particles with a narrow range of size distribution. Most particles are in the range of 80 to 100 nm. Maximum magnetization and coercivity values are also greater for 1 : 2 ratios. These values measured at room temperature are found to be 55 emu/gram and 5000 Oe respectively. XPS and ESR studies support the results.

  15. Eulerian flow modeling of suspensions containing interacting nano-particles: application to colloidal film drying.

    Gergianakis, I.; Meireles, M.; Bacchin, P.; Hallez, Y.

    2015-11-01

    Nano-particles in suspension often experience strong non-hydrodynamic interactions (NHIs) such as electrostatic repulsions. In this work, we present and justify a flow modeling strategy adapted to such systems. Earlier works on colloidal transport in simple flows, were based on the solution of a transport equation for the colloidal volume fraction with a known fluid velocity field and a volume-fraction-dependent diffusion coefficient accounting for mass fluxes due to NHIs. Extension of this modelling to complex flows requires the coupled resolution of a momentum transport equation for the suspension velocity field. We use the framework of the Suspension Balance Model to show that in the Pe Matter]. The influence of the effective Peclet number on the 1D/2D character of the flow is evaluated and the possible colloidal film patterning due to defaults of substrate topography is commented.

  16. BRITTLE-DUCTILE TRANSITION OF PP/EPDM/ELASTOMERIC NANO-PARTICLE TERNARY BLENDS

    Yan Xiao; Wen Cao; Ke Wang; Hong Tan; Qin Zhang; Rong-ni Du; Qiang Fu

    2006-01-01

    The brittle-ductile transition is a very important phenomenon for polymer toughening. Polypropylene (PP) is often toughened by using rubbers, e.g., ethylene-propylene diene monomer (EPDM) has often been used as a modifier. In this article, the toughening of PP by using a new kind of rubber, known as elastomeric nano-particle (ENP), and the brittleductile transition of PP/EPDM/ENP was studied. Compared to PP/EPDM binary blends, the brittle-ductile transition of PP/EPDM/ENP ternary blends occurred at lower EPDM contents. SEM experiment was carried out to investigate the etched and impact-fractured surfaces. ENP alone had no effect on the impact strength of PP, however, with the same EPDM content,PP/EPDM/ENP ternary blends had smaller particle size, better dispersion and smaller interparticle distance in contrary to PP/EPDM binary blends, which promoted the brittle-ductile transition to occur earlier.

  17. Simple Model for Gold Nano Particles Concentration Dependence of Resonance Energy Transfer Intensity

    Hoa, N. M.; Ha, C. V.; Nga, D. T.; Lan, N. T.; Nhung, T. H.; Viet, N. A.

    2016-06-01

    Gold nano particles (GNPs) concentration dependence of the energy transfer occurs between the fluorophores and GNPs is investigated. In the case of theses pairs, GNPs can enhance or quench the fluorescence of fluorophores depending upon the relative magnitudes of two energy transfer mechanisms: i) the plasmonic field enhancement at the fluorophores emission frequencies (plasmon coupled fluorescence enhancement) and ii) the localized plasmon coupled Forster energy transfer from fluorescent particles to gold particles, which quenches the fluorescence. The competition of these mechanisms is depending on the spectral overlap of fluorophores and GNPs, their relative concentration, excitation wavelength. Simple two branches surface plasmon polariton model for GNPs concentration dependence of the energy transfer is proposed. The experimental data and theoretical results confirm our findings.

  18. Tribological Characteristics of Chromium-active Carbon Electroplated Composite Coatings

    GUKa-fi; HUAMeng; Yi-min

    2004-01-01

    A process of chromium electroplating using a standard bath with additives and active carbon particles was reported, and the tribological behaviors of the composite coatings using the pin-on-disk tester and the table wear tester were i nvestig(aed. Experimental results indicate that the electroplated chromium-active carbon composite coatings exhibited the low friction coefficient anti excellent anti-wear properties whets coffered with the normal chromium electroplated ones. The formation of active carbon particles within the chromium matrices can be explained by SEM analysis and the mechanis of wear resistance of the composite coatings were studied.

  19. Zinc oxide nano-particles as sealer in endodontics and its sealing ability

    Maryam Javidi

    2014-01-01

    Full Text Available Aims: The aim of this study was to evaluate the sealing ability of new experimental nano-ZOE-based sealer. Settings and Design: Three types of nano-ZOE-based sealer (calcined at different temperatures of 500, 600 and 700°C with two other commercially available sealers (AH26 and micro-sized zinc oxide eugenol sealer were used. Materials and Methods: Zinc oxide nano-particles were synthesized by a modified sol-gel method. The structure and morphology of the prepared powders were characterized using x-ray diffraction (XRD and transmission electron microscopy (TEM techniques. The instrumented canals of 60 single-rooted teeth were divided into five groups (n = 10, with the remaining ten used as controls. The canals were filled with gutta-percha using one of the materials mentioned above as sealer. After 3, 45 and 90 days, the samples were connected to a fluid filtration system. Statistical Analysis Used: The data were analyzed using Student′s t-test. Results: The XRD patterns and TEM images revealed that all the synthesized powders had hexagonal wurtzite structures with an average particle size of about 30-60 nm at different calcination temperatures. Microleakage in AH26 groups was significantly more than that in three groups of ZnO nano-particles at all the three evaluation intervals. Apical microleakage of ZnO micro-powders was significantly more than that of all the materials, but the sealing ability of ZnO nano-powder sealers did not differ significantly. Conclusion: The results of this study showed that the synthesized ZnO nano-powder sealers are suitable for use as a nano-sealer in root canal therapy to prevent leakage; however, further studies should be carried out to verify their safety.

  20. Modifying Si-based consolidants through the addition of colloidal nano-particles

    Ksinopoulou, E.; Bakolas, A.; Moropoulou, A.

    2016-04-01

    The modification of silicon-based stone consolidants has been the subject of many scientific studies aiming to overcome the commonly reported drawbacks of these materials, such as the tendency to shrink and crack during drying. The addition of nano-particle dispersions into silica matrix has been found to enhance their effectiveness in several ways. Objective of the current research was to study the preparation of particle-modified consolidants (PMC), consisting of an ethyl silicate matrix (TEOS) loaded with colloidal silica (SiO2) nano-particles and oxide titania (TiO2) particles. The effect of the polyacrylic acid on the dispersion stability was also investigated, by varying its concentration into PMC samples. The prepared materials were allowed to dry in two different relative humidity environments and then evaluated based on their stability in the sol phase, the aggregation sizes, determined through dynamic light scattering, the % solids content and their morphological characteristics, observed via scanning electron microscopy (SEM-EDAX). Mercury intrusion porosimetry was also applied to investigate the microstructural characteristics and differences between the prepared consolidants. Significant role in the final form of the material is played by both the initial molar ratios in the mixtures, as well as the conditions where the drying and aging takes place. Based on the results, the three-component PMCs appear to be promising in stone consolidation, as they show a reduction in cracking and shrinkage during drying and a more porous network, compared with the siliceous material, or the two-component TEOS-SiO2 formulation.

  1. Effect of hydroxyapatite nano-particles on morphology, rheology and thermal behavior of poly(caprolactone)/chitosan blends.

    Ghorbani, Fereshte Mohammad; Kaffashi, Babak; Shokrollahi, Parvin; Akhlaghi, Shahin; Hedenqvist, Mikael S

    2016-02-01

    The effect of hydroxyapatite nano-particles (nHA) on morphology, and rheological and thermal properties of PCL/chitosan blends was investigated. The tendency of nHA to reside in the submicron-dispersed chitosan phase is determined using SEM and AFM images. The presence of electrostatic interaction between amide sites of chitosan and ionic groups on the nHA surface was proved by FTIR. It is shown that the chitosan phase is thermodynamically more favorable for the nano-particles to reside than the PCL phase. Lack of implementation of Cox-Merz theory for this system shows that the polymer-nano-particle network is destructed by the flow. Results from dynamic rheological measurements and Zener fractional model show that the presence of nHA increases the shear moduli and relaxation time of the PCL/chitosan blends. DSC measurements showed that nHA nano-particles are responsible for the increase in melting and crystallization characteristics of the PCL/chitosan blends. Based on thermogravimetric analysis, the PCL/chitosan/nHA nano-composites exhibited a greater thermal stability compared to the nHA-free blends. PMID:26652456

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

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

    2013-10-01

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

  3. Study on the effect of surface modifier on self-aggregation behavior of Ag nano-particle

    Graphical abstract: The typical TEM images of the silver NPs were close to mono-disperse spherical with diameters about 10 nm. The Ag/PVP NPs are highly crystalline, and the interplanar spacing of 0.235 nm is close to the separation between the (1 1 1) crystallographic planes of cubic Ag/PVP. Highlights: ► Four kinds of the mono-dispersed silver NPs with different capping agent were synthesized with diameters about 7, 3, 10, and 5 nm, respectively. ► HRTEM characterization also revealed the Ag/PVP, Ag/PAN, Ag/OA NPs are highly crystalline and the interplanar spacing was calculated. ► FTIR and TG-DSC were used to characterize the binding group of four molecules on Ag nano-particle's surface. ► The Effect of Surface Modifier on Self-Aggregation of Ag Nano-particle was discussed. - Abstract: In this study, four kinds of Ag nano-particles were synthesized with poly (vinylpyrrolidone) (PVP), polyaniline (PAN), L-cysteine (L-cys), and oleic acid (OA) as modified groups. The properties of these Ag nano-particles were characterized by several techniques. Transmission electron microscopy (TEM) observation show four samples were close to monodisperse spherical with diameters about 7, 3, 10, and 5 nm, respectively. The interplanar spacing was calculated and the crystal was discussed with X-ray diffraction (XRD) results. Both Fourier transform infrared spectra (FTIR) and thermogravimetry (TG)-differential scanning calorimetry (DSC) has revealed the binding group of four molecules on Ag nano-particle's surface. After the Ag nanoparticles (NPs) deposited onto the substrate, surface modifier would collapse on the particle surface. Ag nanoparticles are easier to self-aggregate for the weaker binding of surface modifier. As a result, the conductive film is formed. The effect of modified group and temperature were discussed on the conductivity of the silver films.

  4. Core-Shell Soy Protein-Soy Polysaccharide Complex (Nano)particles as Carriers for Improved Stability and Sustained Release of Curcumin.

    Chen, Fei-Ping; Ou, Shi-Yi; Tang, Chuan-He

    2016-06-22

    Using soy protein isolate (SPI) and soy-soluble polysaccharides (SSPS) as polymer matrixes, this study reported a novel process to fabricate unique core-shell complex (nano)particles to perform as carriers for curcumin (a typical poorly soluble bioactive). In the process, curcumin-SPI nanocomplexes were first formed at pH 7.0 and then coated by SSPS. At this pH, the core-shell complex was formed in a way the SPI nanoparticles might be incorporated into the interior of SSPS molecules without distinctly affecting the size and morphology of particles. The core-shell structure was distinctly changed by adjusting pH from 7.0 to 4.0. At pH 4.0, SSPS was strongly bound to the surface of highly aggregated SPI nanoparticles, and as a consequence, much larger complexes were formed. The bioaccessibility of curcumin in the SPI-curcumin complexes was unaffected by the SSPS coating. However, the core-shell complex formation greatly improved the thermal stability and controlled release properties of encapsulated curcumin. The improvement was much better at pH 4.0 than that at pH 7.0. All of the freeze-dried core-shell complex preparations exhibited good redispersion behavior. The findings provide a simple approach to fabricate food-grade delivery systems for improved water dispersion, heat stability, and even controlled release of poorly soluble bioactives. PMID:27243766

  5. Active coated nanoparticles: impact of plasmonic material choice

    Arslanagic, Samel; Ziolkowski, R.W.

    2011-01-01

    The near- and far-field properties of a number of active coated spherical nanoparticles excited by an electric Hertzian dipole at optical frequencies are investigated. Their enhanced, as well as reduced, radiation effects are demonstrated and compared.......The near- and far-field properties of a number of active coated spherical nanoparticles excited by an electric Hertzian dipole at optical frequencies are investigated. Their enhanced, as well as reduced, radiation effects are demonstrated and compared....

  6. Application of Nano-Structured Coatings for Mitigation of Flow-Accelerated Corrosion in Secondary Pipe Systems of Nuclear Power Plants

    Kim, Seung Hyun; Kim, Jong Jin; Yoo, Seung Chang; Huh, Jae Hoon; Kim, Ji Hyun [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2014-05-15

    Flow-accelerated corrosion (FAC) is a complex corrosion process combined with mechanical reaction with fluid. There were lots of research to mitigate FAC such as controlling temperature or water chemistry but in this research, we adopt active coating techniques especially nano-particle reinforced coatings. One of the general characteristics of FAC and its mitigation is that surface friction due to surface morphology makes a significant effect on FAC. Therefore to form a uniform coating layers, nano-particles including TiO2, SiC, Fe-Cr-W and Graphene were utilized. Those materials are known as greatly improve the corrosion resistance of substrates such as carbon steels but their effects on mitigation of FAC are not revealed clearly. Therefore in this research, the FAC resistive performance of nano-structured coatings were tested by electrochemical impedance spectroscopy (EIS) in room temperature 15 wt% sulfuric acid. As the flow-accelerated corrosion inhibitors in secondary piping system of nuclear power plants, various kinds of nano-structured coatings were prepared and tested in room-temperature electrochemical cells. SHS7740 with two types of Densifiers, electroless nickel plating with TiO2 are prepared. Electropolarization curves shows the outstanding corrosion mitigation performance of SHS7740 but EIS results shows the promising potential of Ni-P and Ni-P-TiO2 electroless nickel plating. For future work, high-temperature electrochemical analysis system will be constructed and in secondary water chemistry will be simulated.

  7. Microstructural evolution of plasma sprayed submicron-/nano-zirconia-based thermal barrier coatings

    Wang, Y.; Bai, Y.; Liu, K.; Wang, J. W.; Kang, Y. X.; Li, J. R.; Chen, H. Y.; Li, B. Q.

    2016-02-01

    Two types of agglomerates powder with grain sizes in the submicron- /nano-range were used as the feedstock to deposit yttria partially stabilized zirconia (YPSZ) thermal barrier coatings (TBCs). The dual-modal submicron-coating and multi-modal nano-coating were fabricated. The results from thermal shock test indicated that, due to the weak bond and higher densification rate of unmelted nano-particles in the nano-coating, the interface between recrystallization zone and unmelted nano-particles linked up, which resulted in the decrease of content of unmelted nano-particles from 13% to 7%. The weak bond and higher shrinking rate of nano-particles led to the formation of coarse cracks that ran along the recrystallization zone/unmelted nano-particles interfaces. These cracks caused the premature failure of nano-coating. The submicron-coating can overcome the inherent deficiencies of nano-coating at high temperatures and show a higher thermal shock resistance, it is expected to become a candidate for high-performance TBCs.

  8. Acute toxicity of virgin and used engine oil enriched with copper nano particles in the earthworm

    In spite of development of nanotechnology and creation of new opportunities for industry, new applications and products initiated by this technology may cause harmful effects on human health and environment. Unfortunately, there is no sufficient information on the harmful effects caused by application of some nano materials; the current knowledge in this field is limited solely to the nano particles but not the final products. Nano cupper particles, as one of the common materials produced in industrial scale is widely used as additives into engine oil to reduce friction and improve lubrication. However, the difference between the effects of virgin and used conventional engine oil (CEO) and the engine oil containing cupper nano particles (NEO) on the environment is not known. Earthworm, as a one of the species which could live and survive in different sorts of earth and has a certain role in protecting the soil structure and fertility, was used in this experiment. In accordance with the recommended method of OECD.1984, Filter Paper test in 24 and 48 h based on 8 concentrations in the range of 3x10-3 - 24x10-3 ml/cm2 and Artificial Soil test in 7 and 14 days based on 7 concentrations in the range of 0.1 mg/kg - 100 g/kg were carried out to study earthworms in terms of lifetime (LC50), morphology and pathology. It was shown that the 48 h LC50 for virgin CEO, virgin NEO, used CEO(8000 km) and used NEO (8000 km) were 6x10-3, 23x10-3, 24x10-3 and 16x10-3 ml/cm2 respectively. Furthermore, 14-day LC50 in artificial soil for all cases were above 100 g/kg. It is concluded that virgin CEO is more toxic than virgin NEO. Meanwhile, the CEO shows significant reduction in toxicity after consumption and the used NEO shows more toxicity in comparison to virgin product. It seems that more investigations on the effects of final products specifically after consumption is necessary because the products after consumption have the most contact with environment and subsequently human

  9. Acute toxicity of virgin and used engine oil enriched with copper nano particles in the earthworm

    Khodabandeh, M.; Koohi, M. K.; Roshani, A.; Shahroziyan, E.; Badri, B.; Pourfallah, A.; Shams, Gh; Hobbenaghi, R.; Sadeghi-Hashjin, G.

    2011-07-01

    In spite of development of nanotechnology and creation of new opportunities for industry, new applications and products initiated by this technology may cause harmful effects on human health and environment. Unfortunately, there is no sufficient information on the harmful effects caused by application of some nano materials; the current knowledge in this field is limited solely to the nano particles but not the final products. Nano cupper particles, as one of the common materials produced in industrial scale is widely used as additives into engine oil to reduce friction and improve lubrication. However, the difference between the effects of virgin and used conventional engine oil (CEO) and the engine oil containing cupper nano particles (NEO) on the environment is not known. Earthworm, as a one of the species which could live and survive in different sorts of earth and has a certain role in protecting the soil structure and fertility, was used in this experiment. In accordance with the recommended method of OECD.1984, Filter Paper test in 24 and 48 h based on 8 concentrations in the range of 3×10-3 - 24×10-3 ml/cm2 and Artificial Soil test in 7 and 14 days based on 7 concentrations in the range of 0.1 mg/kg - 100 g/kg were carried out to study earthworms in terms of lifetime (LC50), morphology and pathology. It was shown that the 48 h LC50 for virgin CEO, virgin NEO, used CEO(8000 km) and used NEO (8000 km) were 6×10-3, 23×10-3, 24×10-3 and 16×10-3 ml/cm2 respectively. Furthermore, 14-day LC50 in artificial soil for all cases were above 100 g/kg. It is concluded that virgin CEO is more toxic than virgin NEO. Meanwhile, the CEO shows significant reduction in toxicity after consumption and the used NEO shows more toxicity in comparison to virgin product. It seems that more investigations on the effects of final products specifically after consumption is necessary because the products after consumption have the most contact with environment and subsequently

  10. Acute toxicity of virgin and used engine oil enriched with copper nano particles in the earthworm

    Khodabandeh, M; Koohi, M K; Shahroziyan, E; Badri, B; Pourfallah, A; Shams, Gh; Sadeghi-Hashjin, G [Faculty of Veterinary Medicine, University of Tehran, Tehran (Iran, Islamic Republic of); Roshani, A [Industrial and Environmental Protection Division, Research Institute of Petroleum Industry (RRIPI), Tehran (Iran, Islamic Republic of); Hobbenaghi, R, E-mail: gsadeghi@ut.ac.ir [Faculty of Veterinary Medicine, Urmia University, Urmia (Iran, Islamic Republic of)

    2011-07-06

    In spite of development of nanotechnology and creation of new opportunities for industry, new applications and products initiated by this technology may cause harmful effects on human health and environment. Unfortunately, there is no sufficient information on the harmful effects caused by application of some nano materials; the current knowledge in this field is limited solely to the nano particles but not the final products. Nano cupper particles, as one of the common materials produced in industrial scale is widely used as additives into engine oil to reduce friction and improve lubrication. However, the difference between the effects of virgin and used conventional engine oil (CEO) and the engine oil containing cupper nano particles (NEO) on the environment is not known. Earthworm, as a one of the species which could live and survive in different sorts of earth and has a certain role in protecting the soil structure and fertility, was used in this experiment. In accordance with the recommended method of OECD.1984, Filter Paper test in 24 and 48 h based on 8 concentrations in the range of 3x10{sup -3} - 24x10{sup -3} ml/cm{sup 2} and Artificial Soil test in 7 and 14 days based on 7 concentrations in the range of 0.1 mg/kg - 100 g/kg were carried out to study earthworms in terms of lifetime (LC50), morphology and pathology. It was shown that the 48 h LC50 for virgin CEO, virgin NEO, used CEO(8000 km) and used NEO (8000 km) were 6x10{sup -3}, 23x10{sup -3}, 24x10{sup -3} and 16x10{sup -3} ml/cm{sup 2} respectively. Furthermore, 14-day LC50 in artificial soil for all cases were above 100 g/kg. It is concluded that virgin CEO is more toxic than virgin NEO. Meanwhile, the CEO shows significant reduction in toxicity after consumption and the used NEO shows more toxicity in comparison to virgin product. It seems that more investigations on the effects of final products specifically after consumption is necessary because the products after consumption have the most

  11. Chemical characterization, nano-particle mineralogy and particle size distribution of basalt dust wastes.

    Dalmora, Adilson C; Ramos, Claudete G; Oliveira, Marcos L S; Teixeira, Elba C; Kautzmann, Rubens M; Taffarel, Silvio R; de Brum, Irineu A S; Silva, Luis F O

    2016-01-01

    Understanding the geochemistry of basalt alteration is central to the study of agriculture systems. Various nano-minerals play an important role in the mobilization of contaminants and their subsequent uptake by plants. We present a new analytical experimental approach in combination with an integrated analytical protocol designed to study basalt alteration processes. Recently, throughout the world, ultra-fine and nano-particles derived from basalt dust wastes (BDW) during "stonemeal" soil fertilizer application have been of great concern for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the Nova Prata mining district in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/Energy Dispersive Spectroscopy (EDS)/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM/EDS), and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO2, Al2O3, and Fe2O3, with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition, we have identified a number of trace metals such as Cd, Cu, Cr, and Zn, that are preferentially concentrated into the finer, inhalable, dust fraction and, thus, could present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle mineralogy and chemical composition in

  12. Positron Annihilation Study on Nickel and Iron Nano-Particles in Natural Rubber Composites

    Emad H. Aly

    2011-01-01

    Full Text Available Problem statement: The effect of Ni and Fe nano-particles as a filler on the free volume properties Of Natural Rubber (NR was studied using Positron Annihilation Lifetime Spectroscopy (PALS. Approach: The PAL measurements revealed that the free volume properties are strongly affected by the amount and type of filler. Results: Particularly speaking, the free volume fraction dramatically decreased by increasing the filler content. Besides, the addition of nano-prticles created new positron trapping sites at filler-rubber interfaces. Furthermore, correlations were made between the free volume hole sizes (Vh and each of the mechanical and electrical properties successively. A negative correlation was observed between Vh and hardness in the Ni-rubber composites while a positive counterpart was found in the case of Fe-rubber composites. Finally, the polarity of the fillers, being higher than that of the rubber itself, leads to an increase in electrical parameters and an inhibition of o-Ps formation. Conclusion: These results indicate that the investigated composites are considered to be insulating materials as their conductivity values are in the order of an insulator range.

  13. Study on an electrochemical biosensor for thrombin recognition based on aptamers and nano particles

    ZHENG Jing; LIN Li; CHENG GuiFang; WANG AnBao; TAN XueLian; HE PinGang; FANG YuZhi

    2007-01-01

    This paper presents a high specific, sensitive electrochemical biosensor for recognition of protein such as thrombin based on aptamers and nano particles. Two different aptamers were chosen to construct a sandwich manner for detecting thrombin. Aptamer Ⅰ was immobilized on nano magnetic particle for capturing thrombin, and aptamer Ⅱ labled with nano gold was used for detection. The electrical current generated from gold after the formation of the complex of magnetic particle, thrombin and nano gold,and then an electrochemical cell designed by ourselves was used for separating, gathering, and electrochemical detecting. Through magnetic separation, high specific and sensitive detection of the target protein, thrombin, was achieved. Linear response was observed over the range 5.6×10-12-1.12×10-9mol/L, with a detection limit of 1.42×10-12 mol/L. The presence of other protein as BSA did not affect the detection, which indicates that high selective recognition of thrombin can be achieved in complex biological samples such as human plasma.

  14. Study on an electrochemical biosensor for thrombin recognition based on aptamers and nano particles

    2007-01-01

    This paper presents a high specific, sensitive electrochemical biosensor for recognition of protein such as thrombin based on aptamers and nano particles. Two different aptamers were chosen to construct a sandwich manner for detecting thrombin. Aptamer I was immobilized on nano magnetic particle for capturing thrombin, and aptamer II labled with nano gold was used for detection. The electrical current generated from gold after the formation of the complex of magnetic particle, thrombin and nano gold, and then an electrochemical cell designed by ourselves was used for separating, gathering, and electrochemical detecting. Through magnetic separation, high specific and sensitive detection of the target protein, thrombin, was achieved. Linear response was observed over the range 5.6×10-12―1.12×10-9 mol/L, with a detection limit of 1.42×10-12 mol/L. The presence of other protein as BSA did not affect the detection, which indicates that high selective recognition of thrombin can be achieved in complex biological samples such as human plasma.

  15. Fate and effect of tire rubber ash nano-particles (RANPs) in cucumber.

    Moghaddasi, Sahar; Hossein Khoshgoftarmanesh, Amir; Karimzadeh, Fatholah; Chaney, Rufus

    2015-05-01

    There are growing interests on effects of nano-materials on living organisms including higher plants. No report is available on positive and negative effects of rubber ash nano-particles (RANPs) on edible plants. Recently, we reported the possibility of using waste tire rubber and rubber ash as zinc (Zn) fertilizer for plants. In this nutrient solution culture study, for the first time, root uptake and the effects of RANPs on growth and Zn, cadmium (Cd), and lead (Pb) concentration in cucumber was investigated. Various Zn levels (0, 1, 5, 25, 125mgL(-1)) were applied in the form of RANPs or ZnSO4. The root RANPs uptake was visualized by light (LA), scanning electron (SEM), and transmission electron microcopies (TEM). At all Zn levels, cucumber plants supplied with RANPs produced higher shoot and root biomass compared with those supplied with ZnSO4. In addition, the RANPs resulted in higher accumulation of Zn in cucumber tissues in comparison with ZnSO4; although phytotoxicity of Zn from ZnSO4 was greater than that from RANPs. Clear evidence of the RANPs penetration into the root cells was obtained by using SEM and TEM. Filaments of RANPs were also observed at the end of roots by LM and TEM. Further research is needed to clarify the fate of the RANPs in plant cells and their possible risks for food chain. PMID:25700091

  16. Biopolymer nano-particles and natural nano-carriers for nano-encapsulation of phenolic compounds.

    Faridi Esfanjani, Afshin; Jafari, Seid Mahdi

    2016-10-01

    Phenolic compounds are major micronutrients in our diet,(1) and evidence for their role in the prevention of degenerative diseases such as cancer, inflammation and neurodegenerative diseases is emerging. The easily destruction against environment stresses and low bioavailability of phenolics are main limitations of their application. Therefore, nano-encapsulated phenolics as a fine delivery system can solve their restrictions. Polymeric nanoparticles and natural nano-carriers are one of the most effective and industrial techniques which can be used for protection and delivery of phenolics. In this review, preparation, application and characterization of polymeric based nano-capsules and natural nano-carriers for phenolics have been considered and discussed including polymeric nanoparticles, polymeric complex nanoparticles, cyclodextrins, nano-caseins, nanocrystals, electrospun nano-fibers, electro-sprayed nano-particles, and nano-spray dried particles. Our main goal was to cover the relevant recent studies in the past few years. Although a number of different types of polymeric and natural based nano-scale delivery systems have been developed, there are relatively poor quantitative understanding of their in vivo absorption, permeation and release. Also, performing toxicity experiments, residual solvent analysis and studying their biological fate during digestion, absorption, and excretion of polymeric nanoparticle and natural nano-carriers containing phenolics should be considered in future researches. In addition, future investigations could focus on application of phenolic nano-scale delivery systems in pharmaceuticals and functional foods. PMID:27419648

  17. Improved electrical properties of cadmium substituted cobalt ferrites nano-particles for microwave application

    Ahmad, Rabia; Hussain Gul, Iftikhar; Zarrar, Muhammad; Anwar, Humaira; khan Niazi, Muhammad Bilal; Khan, Azim

    2016-05-01

    Cadmium substituted cobalt ferrites with formula CdxCo1-xFe2O4 (x=0.0, 0.2, 0.35, 0.5), have been synthesized by wet chemical co-precipitation technique. Electrical, morphological and Structural properties of the samples have been studied using DC electrical resistivity and Impedance analyzer, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD), respectively. XRD, SEM and AFM have been used to study the structural parameters such as measured density, lattice constant, X-ray density, crystallite size and morphology of the synthesized nano-particles. Debye-Scherrer formula has been used for the estimation of crystallite sizes. The estimated crystallite sizes were to be 15-19±2 nm. Hopping length of octahedral and tetrahedral sites have been calculated using indexed XRD data. The porosity and lattice constant increased as Cd2+concentration increases. DC electrical resistivity was performed using two probe technique. The decrease of resistivity with temperature confirms the semiconducting nature of the samples. The dielectric properties variation has been studied at room temperature as a function of frequency. Variation of dielectric properties from 100 Hz to 5 MHz has been explained on the basis of Maxwell and Wagner's model and hoping of electrons on octahedral sites. To separates the grains boundary and grains of the system CdxCo1-xFe2O4 the impedance analysis were performed.

  18. The effect of acid-base clustering and ions on the growth of atmospheric nano-particles

    Lehtipalo, Katrianne; Rondo, Linda; Kontkanen, Jenni; Schobesberger, Siegfried; Jokinen, Tuija; Sarnela, Nina; Kürten, Andreas; Ehrhart, Sebastian; Franchin, Alessandro; Nieminen, Tuomo; Riccobono, Francesco; Sipilä, Mikko; Yli-Juuti, Taina; Duplissy, Jonathan; Adamov, Alexey; Ahlm, Lars; Almeida, João; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; Dommen, Josef; Downard, Andrew J.; Dunne, Eimear M.; Flagan, Richard C.; Guida, Roberto; Hakala, Jani; Hansel, Armin; Jud, Werner; Kangasluoma, Juha; Kerminen, Veli-Matti; Keskinen, Helmi; Kim, Jaeseok; Kirkby, Jasper; Kupc, Agnieszka; Kupiainen-Määttä, Oona; Laaksonen, Ari; Lawler, Michael J.; Leiminger, Markus; Mathot, Serge; Olenius, Tinja; Ortega, Ismael K.; Onnela, Antti; Petäjä, Tuukka; Praplan, Arnaud; Rissanen, Matti P.; Ruuskanen, Taina; Santos, Filipe D.; Schallhart, Simon; Schnitzhofer, Ralf; Simon, Mario; Smith, James N.; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Tomé, António; Vaattovaara, Petri; Vehkamäki, Hanna; Vrtala, Aron E.; Wagner, Paul E.; Williamson, Christina; Wimmer, Daniela; Winkler, Paul M.; Virtanen, Annele; Donahue, Neil M.; Carslaw, Kenneth S.; Baltensperger, Urs; Riipinen, Ilona; Curtius, Joachim; Worsnop, Douglas R.; Kulmala, Markku

    2016-05-01

    The growth of freshly formed aerosol particles can be the bottleneck in their survival to cloud condensation nuclei. It is therefore crucial to understand how particles grow in the atmosphere. Insufficient experimental data has impeded a profound understanding of nano-particle growth under atmospheric conditions. Here we study nano-particle growth in the CLOUD (Cosmics Leaving OUtdoors Droplets) chamber, starting from the formation of molecular clusters. We present measured growth rates at sub-3 nm sizes with different atmospherically relevant concentrations of sulphuric acid, water, ammonia and dimethylamine. We find that atmospheric ions and small acid-base clusters, which are not generally accounted for in the measurement of sulphuric acid vapour, can participate in the growth process, leading to enhanced growth rates. The availability of compounds capable of stabilizing sulphuric acid clusters governs the magnitude of these effects and thus the exact growth mechanism. We bring these observations into a coherent framework and discuss their significance in the atmosphere.

  19. Magnetic behaviour of nano-particles of Fe2.8Zn0.2O4

    Subhash Chander; Seema Lakhanpal; Anjali Krishnamurthy; Bipin K Srivastava; V K Aswal

    2004-08-01

    Magnetization measurements are reported on a nano-particle sample of Zn- substituted spinel ferrite Fe2.8Zn0.2O4 in the temperature range 20-300 K. Analysis of small-angle neutron scattering data shows the sample to have a log-normal particle size distribution of median diameter 64.4 Å and standard deviation 0.38. Magnetization evolves over a long period of time going nearly linearly with log . Magnetic anisotropy, estimated by fitting -log curve, shows many fold increase over that of bulk particle sample. Major enhancement owes to disordered moments in surface layer. In the nano-particle state as well increasing amount of Zn causes anisotropy to decrease.

  20. Comparison of the influence of Cu micro- and nano-particles on the thermal properties of polyethylene/Cu composites

    2009-10-01

    Full Text Available Polyethylene (LDPE, LLDPE and HDPE composites with different copper (micro- and nano-sized particles contents were prepared by melt mixing and compression moulding. The melting and crystallization behaviour of the different composites was analysed using a differential scanning calorimeter (DSC, and the thermal stability in a thermogravimetric analyser (TGA. The thermal conductivities of the samples were also determined. The DSC results show that the Cu micro- and nano-particles influence the crystallization behaviour of the polyethylenes in different ways. The extent to which the copper particles influence the crystallization behaviour of the polyethylenes also depends on the respective morphologies of the different polyethylenes. The TGA results show an observable influence of both the presence of copper and the sizes of the copper particles on the thermal stabilities of the polymers. Thermal conductivities increased with increasing Cu content, but there was little difference between the thermal conductivities of the samples containing Cu micro- and nano-particles.

  1. Measurement of nano-particle diffusion in the simulated dynamic light scattering by contrast of dynamic images

    Wu, Xiaobin; Qiu, Jian; Luo, Kaiqing; Han, Peng

    2015-08-01

    Dynamic Light Scattering is used for measuring particle size distribution of nano-particle under Brownian motion. Signal is detected through a photomultiplier and processed by correlation analysis, and results are inverted at last. Method by using CCD camera can record the procedure of motion. However, there are several weaknesses such as low refresh speed and noise from CCD camera, and this method depends on particle size and detecting angle. A simulation of nano-particle under Brownian motion is proposed to record dynamic images, studies contrast of dynamic images which can represent speed of diffusion, and its characteristic under different conditions. The results show that through contrast of dynamic images diffusion coefficient can be obtained, which is independent on density of scattering volume.

  2. Aqueous Phase Glycerol Reforming by PtMo Bimetallic Nano-Particle Catalyst: Product Selectivity and Structural Characterization

    Stach E. A.; Dietrich, P.J.; Lobo-Lapidus, R.J.; Wu, T.; Sumer, A.; Akatay, M.C.; Fingland, B.R.; Guo, N.; Dumesic, J.A.; Marshall, C.L.; Jellinek, J.; Delgass, W.N.; Ribeiro, F.H.; Miller, J.T.

    2012-03-01

    A carbon supported PtMo aqueous phase reforming catalyst for producing hydrogen from glycerol was characterized by analysis of the reaction products and pathway, TEM, XPS and XAS spectroscopy. Operando X-ray absorption spectroscopy (XAS) indicates the catalyst consists of bimetallic nano-particles with a Pt rich core and a Mo rich surface. XAS of adsorbed CO indicates that approximately 25% of the surface atoms are Pt. X-ray photoelectron spectroscopy indicates that there is unreduced and partially reduced Mo oxide (MoO{sub 3} and MoO{sub 2}), and Pt-rich PtMo bimetallic nano-particles. The average size measured by transmission electron microscopy of the fresh PtMo nano-particles is about 2 nm, which increases in size to 5 nm after 30 days of glycerol reforming at 31 bar and 503 K. The catalyst structure differs from the most energetically stable structure predicted by density functional theory (DFT) calculations for metallic Pt and Mo atoms. However, DFT indicates that for nano-particles composed of metallic Pt and Mo oxide, the Mo oxide is at the particle surface. Subsequent reduction would lead to the experimentally observed structure. The aqueous phase reforming reaction products and intermediates are consistent with both C-C and C-OH bond cleavage to generate H{sub 2}/CO{sub 2} or the side product CH{sub 4}. While the H{sub 2} selectivity at low conversion is about 75%, cleavage of C-OH bonds leads to liquid products with saturated carbon atoms. At high conversions (to gas), these will produced additional CH{sub 4} reducing the H{sub 2} yield and selectivity.

  3. Study of Nano Particles for Enhanced Heat Transfer Characteristics of Base Fluids for Cool Thermal Energy System

    Promit Choudhury; Priya Garg

    2014-01-01

    Reliable heat transfer is very crucial for heat demand and supply related applications where the optimum demand is not met. Cool thermal energy systems are the units which find application in conditioning and preserving items. A colloidal mixture of nano particles in a base fluid tremendously enhances the heat transfer characteristics of the original base fluid and is ideally suited for practical application due to its marvelous characteristics.

  4. Study of Nano Particles for Enhanced Heat Transfer Characteristics of Base Fluids for Cool Thermal Energy System

    Promit Choudhury

    2014-04-01

    Full Text Available Reliable heat transfer is very crucial for heat demand and supply related applications where the optimum demand is not met. Cool thermal energy systems are the units which find application in conditioning and preserving items. A colloidal mixture of nano particles in a base fluid tremendously enhances the heat transfer characteristics of the original base fluid and is ideally suited for practical application due to its marvelous characteristics.

  5. Selective imaging of nano-particle contrast agents by a single-shot x-ray diffraction technique

    Stein, Ashley F.; Ilavsky, Jan; Kopace, Rael; Bennett, Eric E.; Wen, Han

    2010-01-01

    Iron oxide nano-particles have very different x-ray diffraction properties from tissue. They can be clearly visualized against suppressed tissue background in a single-shot x-ray diffraction imaging technique. This technique is able to acquire both diffraction and absorption images from a single grating-modulated projection image through analysis in the spatial frequency domain. We describe the use of two orthogonal transmission gratings to selectively retain diffraction signal from iron oxid...

  6. Dispensing of high concentration Ag nano-particles ink for ultra-low resistivity paper-based writing electronics

    Fuliang Wang; Peng Mao; Hu He

    2016-01-01

    Paper-based writing electronics has received a lot of interest recently due to its potential applications in flexible electronics. To obtain ultra-low resistivity paper-based writing electronics, we developed a kind of ink with high concentration of Ag Nano-particles (up to 80 wt%), as well as a related dispensing writing system consisting an air compressor machine and a dispenser. Additionally, we also demonstrated the writability and practical application of our proposed ink and writing sys...

  7. Growth of a brittle crack (001) in 3D bcc iron crystal with a Cu nano-particle

    Uhnáková, Alena; Machová, Anna; Hora, Petr; Červená, Olga

    2014-01-01

    Roč. 83, February (2014), s. 229-234. ISSN 0927-0256 R&D Projects: GA ČR GA101/09/1630 Institutional support: RVO:61388998 Keywords : brittle crack extension * 3D * mode I * bcc iron * Cu nano-particle * molecular dynamics * acoustic emission Subject RIV: JG - Metallurgy Impact factor: 2.131, year: 2014 http://www.sciencedirect.com/science/article/pii/S0927025613006575

  8. Effect of impregnation of La0.85Sr0.15MnO3/Yttria Stabilized Zirconia Solid Oxide Fuel Cell cathodes with La0.85Sr0.15MnO3 or Al2O3 nano-particles

    Kammer Hansen, Kent; Wandel, Marie; Liu, Yi-Lin; Mogensen, Mogens Bjerg

    2010-01-01

    electrodes if the temperature was kept low after the impregnation with strontium substituted lanthanum manganite. On good performing electrodes the effect disappeared on heating. Alumina nano-particles had a detrimental effect on the activity of the strontium substituted lanthanum manganite based electrodes.......Strontium substituted lanthanum manganite and yttria stabilized zirconia solid oxide fuel cell composite electrodes were impregnated with nano-particles of strontium substituted lanthanum manganite or alumina. A clear positive effect was observed on low performing electrodes and on good performing...

  9. Antibacterial activity of zinc oxide-coated nanoporous alumina

    Highlights: ► Atomic layer deposition was used to deposit ZnO on nanoporous alumina membranes. ► Scanning electron microscopy showed continuous coatings of zinc oxide nanocrystals. ► Activity against B. subtilis, E. coli, S. aureus, and S. epidermidis was shown. - Abstract: Nanoporous alumina membranes, also known as anodized aluminum oxide membranes, are being investigated for use in treatment of burn injuries and other skin wounds. In this study, atomic layer deposition was used for coating the surfaces of nanoporous alumina membranes with zinc oxide. Agar diffusion assays were used to show activity of zinc oxide-coated nanoporous alumina membranes against several bacteria found on the skin surface, including Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis. On the other hand, zinc oxide-coated nanoporous alumina membranes did not show activity against Pseudomonas aeruginosa, Enterococcus faecalis, and Candida albicans. These results suggest that zinc oxide-coated nanoporous alumina membranes have activity against some Gram-positive and Gram-negative bacteria that are associated with skin colonization and skin infection.

  10. Antibacterial activity of zinc oxide-coated nanoporous alumina

    Skoog, S.A. [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Bayati, M.R. [Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, NC 27695-7907 (United States); Petrochenko, P.E. [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Division of Biology, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993 (United States); Stafslien, S.; Daniels, J.; Cilz, N. [Center for Nanoscale Science and Engineering, North Dakota State University, 1805 Research Park Drive, Fargo, ND 58102 (United States); Comstock, D.J.; Elam, J.W. [Energy Systems Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Narayan, R.J., E-mail: roger_narayan@msn.com [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, NC 27695-7907 (United States)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Atomic layer deposition was used to deposit ZnO on nanoporous alumina membranes. Black-Right-Pointing-Pointer Scanning electron microscopy showed continuous coatings of zinc oxide nanocrystals. Black-Right-Pointing-Pointer Activity against B. subtilis, E. coli, S. aureus, and S. epidermidis was shown. - Abstract: Nanoporous alumina membranes, also known as anodized aluminum oxide membranes, are being investigated for use in treatment of burn injuries and other skin wounds. In this study, atomic layer deposition was used for coating the surfaces of nanoporous alumina membranes with zinc oxide. Agar diffusion assays were used to show activity of zinc oxide-coated nanoporous alumina membranes against several bacteria found on the skin surface, including Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis. On the other hand, zinc oxide-coated nanoporous alumina membranes did not show activity against Pseudomonas aeruginosa, Enterococcus faecalis, and Candida albicans. These results suggest that zinc oxide-coated nanoporous alumina membranes have activity against some Gram-positive and Gram-negative bacteria that are associated with skin colonization and skin infection.

  11. Synthesis of supported metallic nano-particles and their use in air depollution; Des nanoparticules metalliques supportees pour la depollution de l'air

    Barrault, J. [Centre National de la Recherche Scientifique (CNRS), 86 - Poitiers (France); Valange, S. [Poitiers Univ., 86 (France); Tatibouet, J.M. [Centre National de la Recherche Scientifique (CNRS), Lab. de Catalyse en Chimie Organique, UMR CNRS 6503, 86 - Poitiers (France); Thollon, St. [CEA Grenoble (DRT/DTNM/LTS), 38 (France); Herlin-Boime, N. [CEA Saclay, IRAMIS, Service des Photons, Atomes et Molecules, Lab. Francis Perrin, CEA-CNRS URA 2453, 91 - Gif-sur-Yvette (France); Giraud, S. [CEA Saclay (DEN/SRMA), 91 - Gif-sur-Yvette (France); Ruiz, J.Ch. [CEA Marcoule (DTCD/SPDE/LFSM), 30 (France); Bergaya, B. [CRT Plasma lASER, 45 - Orleans (France); Joulin, J.P.; Delbianco, N. [Ceramiques Techniques Industrielles (CTI-SA), 30 - Salindres (France); Gabelica, Z. [Universite de Haute-Alsace (LPI-GSEC), ENSCMu, 68 - Mulhouse (France); Daturi, M. [Ecole Nationale Superieure d' Ingenieurs de Caen (ENSICAEN), CNRS-LCS, UMR 6506, 14 - Caen (France)

    2009-06-15

    The main objectives of the 'NACACOMO' Consortium ('Nano-materials: Catalysts for the Conversion of organic Molecules. Uses in fine chemicals and environment protection ') consisted in generating novel catalysts composed of nanoparticles of metals (Pt, Pd, Ag...) and/or oxides (TiO{sub 2}...) stabilized and well distributed over the surface of a support (foams, ceramics), by monitoring both the particle size and the 'coating' process itself, using new technologies: CVD, plasma-spray, laser pyrolysis, supercritical preparation, which were compared to conventional soft chemistry recipes. The most accurate characterization of particle morphology, local structure, texture, spatial arrangement but also of their reactivity, were achieved by privileging the utilization of various in situ methods. Details on formation mechanisms of a solid nano-particle at the atomic level (nucleation, growth and particle (re)distribution over the support...) could be obtained in selected cases, with opportunities for scaling up and shaping. The (chemical) nature of the so-obtained nano-materials was monitored for selected catalytic applications involving the development of environmental friendly processes, such as oxidation of VOC, with a priority for aromatics and chlorinated compounds. (authors)

  12. Bimodal porous silica microspheres decorated with polydopamine nano-particles for the adsorption of methylene blue in fixed-bed columns.

    Ataei-Germi, Taher; Nematollahzadeh, Ali

    2016-05-15

    Bimodal meso/macro-porous silica microspheres (MSM) were synthesized by a modified sol-emulsion-gel method and then the surface was coated with polydopamine (PDA) nano-particles of 39nm in size. Focusing on the encouraging properties of the synthesized adsorbent, such as high specific surface area (612.3m(2)g(-1), because of mesopores), fast mass transfer (0.9-2.67×10(-3)mLmin(-1)mg, because of macropores), and abundant "adhesive" functional groups of PDA, it was used for the removal of methylene blue (MB) from aqueous solution in a fixed-bed column. The effect of different parameters such as pH, initial concentration, and flow rate was studied. The results revealed that an appropriate sorption condition is an alkaline solution of MB (e.g., pH 10) at low flow rate (less than 5mLmin(-1)). Furthermore, the compatibility of the experimental data with mathematical models such as Thomas and Adams-Bohart was investigated. Both of the models showed a good agreement with the experimental data (R(2)=0.9954-0.9994), and could be applied for the prediction of the column properties and breakthrough curves. Regeneration of the column was performed by using HCl solution with a concentration of 0.1M as an eluent. PMID:26943002

  13. Study of the effect of Titanium dioxide nano particle size on efficiency of the dye-sensitized Solar cell using natural Pomegranate juice

    A Behjat

    2015-01-01

    Full Text Available Dye-sensitized solar cell (DSSC using natural Pomegranate juice as dye-sensitizeris fabricated and characterized. DSSCS consist of a working electrode, a redox electrolyte containing iodide and tri-iodide ions and a counter electrode. A nanocrystalline TiO2 semiconductor with a wide band-gap coated with a monolayer dye-sensitizer is used as working electrode. The effect of titanium dioxide (TiO2 nanoparticle size on efficiency of the DSSC based Pomegranate juice as a sensitizer is studied. For monolayer structure, we used two sizes of TiO2 nanoparticle (25 nm and 100 nm and a mixture of these two sizes. The highest efficiency of 0.61% was obtained with mixture of 25 and 100 nm TiO2 nano-particles in working electrode. For double-layer structure, we used 100 and 400 nm size TiO2 particles as light-scattering. The best efficiency was obtained using 400 nm TiO2 as light-scattering particles.

  14. Synthesis of metals chalcogenides nano-particles from H2X (X=S, Se, Te) produced electrochemically

    In this work, an electrochemical method to produce H2X (X=S, Se, Te) hydrides in a controlled way (without being able to store them) and to transfer them directly in the synthesis reactor has been perfected. By this method, the use of H2Te has been possible. The method uses the reduction of the elementary chalcogenide in acid medium. The Te being conductor, it can be directly used as electrode, on the other hand S and Se are insulators. Nevertheless, graphite-S or Se conducing composite electrodes can also be used. When the electrolyte composition (pH, salts presence) is well adjusted, the essential of the cathodic current is consumed by the chalcogenide reduction (low evolution of H2) with faradic yields of about 100% for H2S and H2Se and 40% for HeTe. The use of H2X allows the synthesis of nano-particles of metals chalcogenides directly by reaction with dissolved metallic salts in aqueous or organic medium and precipitation. Thus it has been possible to prepare all the CdX compounds under the form of nano-particles of diameter between 3 and 5 nm by bubbling of the gaseous hydrides in aqueous acetate solutions of Cd. In producing concomitantly H2S and H2Se, nano-particles of solid solutions CdSxSe1-x have been synthesized too. (O.M.)

  15. Dose limited reliability of quantitative annular dark field scanning transmission electron microscopy for nano-particle atom-counting

    De Backer, A.; Martinez, G.T. [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); MacArthur, K.E.; Jones, L. [Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH (United Kingdom); Béché, A. [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Nellist, P.D. [Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH (United Kingdom); Van Aert, S., E-mail: sandra.vanaert@uantwerpen.be [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2015-04-15

    Quantitative annular dark field scanning transmission electron microscopy (ADF STEM) has become a powerful technique to characterise nano-particles on an atomic scale. Because of their limited size and beam sensitivity, the atomic structure of such particles may become extremely challenging to determine. Therefore keeping the incoming electron dose to a minimum is important. However, this may reduce the reliability of quantitative ADF STEM which will here be demonstrated for nano-particle atom-counting. Based on experimental ADF STEM images of a real industrial catalyst, we discuss the limits for counting the number of atoms in a projected atomic column with single atom sensitivity. We diagnose these limits by combining a thorough statistical method and detailed image simulations. - Highlights: • Limited size and beam sensitivity of nano-particles challenge their quantification. • Keeping the electron dose to a minimum is therefore important. • Reliability of quantitative ADF STEM for atom-counting is demonstrated. • Limits for single atom sensitivity are discussed. • Limits are diagnosed by combining simulations and a statistical method.

  16. Directly exfoliated and imprinted graphite nano-particle saturable absorber for passive mode-locking erbium-doped fiber laser

    By directly brushing and scribing an ultra-thin (< 5-μm thick) polymer polyvinyl alcohol (PVA) film on one end-face of a FC/APC connector in erbium-doped fiber laser (EDFL), and then imprinting it with the graphite nano-particles exfoliated from a graphite foil, the intra-cavity graphite nano-particle based saturable absorber can be formed to induce passive mode-locking effect in the EDFL. Such a novel approach greatly suppresses the film-thickness induced laser-beam divergent loss to 3.4%, thus enhancing the intra-cavity circulating power to promote the shortening on mode-locking pulsewidth. The saturable absorber with area coverage ratio of graphite nano-particles is detuned from 70 to 25% to provide the modulation depth enhancing from 11 to 20% and the saturated transmittance from 27 to 60%. Optimizing the coverage ratio reduces the non-saturable loss to 40% and enhances the modulation depth to 21%, such that the sub-ps soliton mode-locking can be initiated to provide a chirped pulsewidth of 482 fs and a linewidth of 2.87 nm

  17. Dose limited reliability of quantitative annular dark field scanning transmission electron microscopy for nano-particle atom-counting

    Quantitative annular dark field scanning transmission electron microscopy (ADF STEM) has become a powerful technique to characterise nano-particles on an atomic scale. Because of their limited size and beam sensitivity, the atomic structure of such particles may become extremely challenging to determine. Therefore keeping the incoming electron dose to a minimum is important. However, this may reduce the reliability of quantitative ADF STEM which will here be demonstrated for nano-particle atom-counting. Based on experimental ADF STEM images of a real industrial catalyst, we discuss the limits for counting the number of atoms in a projected atomic column with single atom sensitivity. We diagnose these limits by combining a thorough statistical method and detailed image simulations. - Highlights: • Limited size and beam sensitivity of nano-particles challenge their quantification. • Keeping the electron dose to a minimum is therefore important. • Reliability of quantitative ADF STEM for atom-counting is demonstrated. • Limits for single atom sensitivity are discussed. • Limits are diagnosed by combining simulations and a statistical method

  18. Spin-dependent-magnetoresistance control by regulation of heat treatment temperature for magnetite nano-particle sinter

    Asahi, T.; Yamasaki, Y.; Sugimura, A. [Department of Physics, Faculty of Science and Engineering, Konan University Okamoto 8-9-1, Higashi Nada-ku, Kobe, Hyogo 658-8501 (Japan); Taniguchi, T. [Department of Physics, Faculty of Science, Osaka University Machikaneyama 1-1, Toyonaka, Osaka 560-0043 (Japan); Ando, A.; Kawanaka, H.; Naitoh, Y.; Shimizu, T. [Nanotechnology Research Institute, Advanced Industrial Science and Technology AIST Tsukuba Central, Tsukuba, Ibaraki 305-8568 (Japan); Kobori, H.

    2009-12-15

    The control of spin-dependent-magnetoresistance by regulation of the heat treatment (HT) temperature for magnetite (Fe{sub 3}O{sub 3}) nano-particle sinter (MNPS) has been studied. The average nano-particle size in the MNPS is 30nm and the HT was carried out from 400 C to 800 C. The HT of the MNPS varies the coupling form between adjacent magnetite nano-particles and the crystallinity of that. The measurements on electrical resistance (ER), magnetoresistance (MR) and magnetization were performed between 4K and 300K. The behavior of the ER and MR considerably changes at the HT temperature of {proportional_to}600 C. Below {proportional_to}600 C the ER indicates the variable-range-hopping conduction behavior and the MR shows the large intensity in a wide temperature region. Above {proportional_to}600 C the ER shows the indication of the Verwey transition near 110K like a bulk single crystal and the MR designates the smaller intensity. We consider that below {proportional_to}600 C the ER and MR are dominated by the grain-boundary conduction and above {proportional_to}600 C those are determined by the inter-grain conduction. The magnetic field application to the grain-boundary region is inferred to cause the large enhancement of the MR. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  19. Microfibrillated cellulose coatings as new release systems for active packaging.

    Lavoine, Nathalie; Desloges, Isabelle; Bras, Julien

    2014-03-15

    In this work, a new use of microfibrillated cellulose (MFC) is highlighted for high-added-value applications. For the first time, a nanoporous network formed by MFC coated on paper is used for a controlled release of molecules. The release study was carried out in water with caffeine as a model molecule. The release process was studied by means of (i) continuous, and (ii) intermittent diffusion experiments (with renewal of the medium every 10 min). The effect of the MFC was first observed for the samples impregnated in the caffeine solution. These samples, coated with MFC (coat weight of about 7 g/m(2)), released the caffeine over a longer period (29 washings compared with 16), even if the continuous diffusions were similar for both samples (without and with MFC coating). The slowest release of caffeine was observed for samples coated with the mixture (MFC+caffeine). Moreover, the caffeine was only fully released 9h after the release from the other samples was completed. This study compared two techniques for the introduction of model molecules in MFC-coated papers. The latter offers a more controlled and gradual release. This new approach creates many opportunities especially in the food-packaging field. A similar study could be carried out with an active species. PMID:24528763

  20. Experiment on heat transfer and absorption performance enhancement for binary nanofluids (NH{sub 3}/H{sub 2}O + Nano-Particles)

    Lee, Jin Ki; Jung, Chung Woo; Kang, Yong Tae [Kyunghee Univ., Yongin (Korea, Republic of)

    2008-09-15

    The objectives of this paper are to examine the effect of nano-particles on the pool type absorption heat transfer enhancement and to find the optimal conditions to design a highly effective compact absorber for ammonia/water absorption system. The effect of AL{sub 2}O{sub 3} nano-particles and Carbon NanoTube(CNT) on the absorption performance is studied experimentally. The experimental ranges of the key parameters are 20% of ammonia concentration, 0{approx}0.08 vol% (volume fraction) of CNT particles, and 0{approx}0.06 vol% of Al{sub 2}O{sub 3} nano-particles. For the ammonia/water nanofluids, the heat transfer rate and absorption rate with 0.02 vol% Al{sub 2}O{sub 3} nano-particles were found to be 29% and 18% higher than those without nano-particles respectively. It is recommended that the concentration of 0.02 vol% of Al{sub 2}O{sub 3} nano-particles be the best candidate for ammonia/water absorption performance enhancement.

  1. Beam energy considerations for gold nano-particle enhanced radiation treatment

    Van den Heuvel, F; Nuyts, S [Department of Experimental Radiotherapy, University of Leuven, Leuven (Belgium); Locquet, Jean-Pierre, E-mail: frank.vandenheuvel@med.kuleuven.b [Solid State Physics and Magnetism Section, University of Leuven, Leuven (Belgium)

    2010-08-21

    A novel approach using nano-technology enhanced radiation modalities is investigated. The proposed methodology uses antibodies labeled with organically inert metals with a high atomic number. Irradiation using photons with energies in the kilo-electron volt (keV) range shows an increase in dose due to a combination of an increase in photo-electric interactions and a pronounced generation of Auger and/or Coster-Kroenig (A-CK) electrons. The dependence of the dose deposition on various factors is investigated using Monte Carlo simulation models. The factors investigated include agent concentration, spectral dependence looking at mono-energetic sources as well as classical bremsstrahlung sources. The optimization of the energy spectrum is performed in terms of physical dose enhancement as well as the dose deposited by Auger and/or Coster-Kroenig electrons and their biological effectiveness. A quasi-linear dependence on concentration and an exponential decrease within the target medium is observed. The maximal dose enhancement is dependent on the position of the target in the beam. Apart from irradiation with low-photon energies (10-20 keV) there is no added benefit from the increase in generation of Auger electrons. Interestingly, a regular 110 kVp bremsstrahlung spectrum shows a comparable enhancement in comparison with the optimized mono-energetic sources. In conclusion we find that the use of enhanced nano-particles shows promise to be implemented quite easily in regular clinics on a physical level due to the advantageous properties in classical beams.

  2. Beam energy considerations for gold nano-particle enhanced radiation treatment

    Van den Heuvel, F.; Locquet, Jean-Pierre; Nuyts, S.

    2010-08-01

    A novel approach using nano-technology enhanced radiation modalities is investigated. The proposed methodology uses antibodies labeled with organically inert metals with a high atomic number. Irradiation using photons with energies in the kilo-electron volt (keV) range shows an increase in dose due to a combination of an increase in photo-electric interactions and a pronounced generation of Auger and/or Coster-Krönig (A-CK) electrons. The dependence of the dose deposition on various factors is investigated using Monte Carlo simulation models. The factors investigated include agent concentration, spectral dependence looking at mono-energetic sources as well as classical bremsstrahlung sources. The optimization of the energy spectrum is performed in terms of physical dose enhancement as well as the dose deposited by Auger and/or Coster-Krönig electrons and their biological effectiveness. A quasi-linear dependence on concentration and an exponential decrease within the target medium is observed. The maximal dose enhancement is dependent on the position of the target in the beam. Apart from irradiation with low-photon energies (10-20 keV) there is no added benefit from the increase in generation of Auger electrons. Interestingly, a regular 110 kVp bremsstrahlung spectrum shows a comparable enhancement in comparison with the optimized mono-energetic sources. In conclusion we find that the use of enhanced nano-particles shows promise to be implemented quite easily in regular clinics on a physical level due to the advantageous properties in classical beams.

  3. Chemical modification of titanium isopropoxide for producing stable dispersion of titania nano-particles

    Stable colloidal TiO2 nano-particles are synthesized through the controlled hydrolysis of chemically modified titanium (Ti) isopropoxide with acetylacetone and acetic acid whereas ammonium salts of poly(acrylic acid) is used as a dispersing agent. Acetylacetone and acetic acid used as chelating ligand to retard the hydrolysis and condensation rates. The process is found promising for producing homogeneous aqueous phase colloidal dispersion of TiO2 particles. Fourier transformed infrared and nuclear magnetic resonance spectra reveal the formation of monodentate bridging of ligands with Ti-isopropoxide. UV–Vis spectroscopy confirms the effective adsorption of poly(acrylic acid) within the modified Ti precursor. Zeta potential of modified titanium isopropoxide precursor is measured to understand its stability in different pH. The thermal stability of the precursors modified with different chelating ligands and dispersing agent has been studied using thermo-gravimetric in conjunction to differential thermal analysis (TG-DTA). Phase formation behavior and the morphological features of the synthesized particles are studied using X-ray diffraction and electron microscopy techniques. The sizes of the anatase phase particles are found in the range of 12–20 nm. - Highlights: • Nanosized colloidal TiO2 is prepared by controlled hydrolysis of Ti-isopropoxide. • Effect of chelating and dispersing agent on stability of colloidal TiO2 is studied. • Phase, morphology and stability of colloidal TiO2 are investigated. • The sizes of synthesized TiO2 particles are found in the range of 12–20 nm. • Suitable chelating and dispersing agent can improve particle loading in sol

  4. Synthesis and characterisation of Samarium (III) oxide (Sm2O3) nano particles by hydrothermal method

    Today there is an increasing need for high purity rare earth compounds in various fields, the optical, the electronics, the ceramic, the nuclear and geochemistry. Wide band-gap semiconducting rare earth oxides (REO) have widely used in thin film microcircuit elements, photoelectric devices, electrical switches, re-programmable memory elements and optical devices. Recent advances in creating and characterizing size selected rare earth atomic clusters in the range 1-100 nm have enabled the first tentative steps in the synthesis of a wide range of new materials from nanoscale particles. Nanometer-sized materials are of greatest interest because they have novel physical and chemical properties that are not characteristic of the atoms or of the bulk counterparts. The large ratio of surface area to volume can contribute to some of the unique properties of nanoparticles. The oxides of rare earths such as samarium, erbium, yttrium, europium and cerium have many important applications. Samarium oxide Sm2O3 has special uses in neutron absorber in control rods for nuclear power reactors, solid oxide fuel cell applications, phosphors, lasers and thermoelectric devices. It can also be used in optical glass manufacturing and in the electronic industry. In this paper, a promising rare earth oxide Sm2O3 nano particles have been synthesized by hydrothermal technique using an aqueous Sm(NO3)3.6H2O and Sm2(C2O4)3.10H2O solutions gel precursors. The as prepared solution was placed in a Teflon lined autoclave (volume-55 ml, degree of filling-80%). Time of isothermal hydrothermal treatment was made at temperatures 573 K at 24 h. The products were isolated subsequent washing by distilled water, and dried afterward at 80 deg C. The present study is a report Sm2O3 as nanoparticles, synthesis and characterizing the powder concerning the composition, structural, optical and surface morphology. (author)

  5. Protection of cisplatin-induced spermatotoxicity, DNA damage and chromatin abnormality by selenium nano-particles

    Rezvanfar, Mohammad Amin; Rezvanfar, Mohammad Ali [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of); Shahverdi, Ahmad Reza [Department of Pharmaceutical Biotechnology and Biotechnology Research Centre, Faculty of Pharmacy, TUMS, Tehran (Iran, Islamic Republic of); Ahmadi, Abbas [Department of Histology and Embryology, Faculty of Veterinary Medicine, Urmia University, Urmia (Iran, Islamic Republic of); Baeeri, Maryam; Mohammadirad, Azadeh [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of); Abdollahi, Mohammad, E-mail: mohammad.abdollahi@utoronto.ca [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of)

    2013-02-01

    Cisplatin (CIS), an anticancer alkylating agent, induces DNA adducts and effectively cross links the DNA strands and so affects spermatozoa as a male reproductive toxicant. The present study investigated the cellular/biochemical mechanisms underlying possible protective effect of selenium nano-particles (Nano-Se) as an established strong antioxidant with more bioavailability and less toxicity, on reproductive toxicity of CIS by assessment of sperm characteristics, sperm DNA integrity, chromatin quality and spermatogenic disorders. To determine the role of oxidative stress (OS) in the pathogenesis of CIS gonadotoxicity, the level of lipid peroxidation (LPO), antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) and peroxynitrite (ONOO) as a marker of nitrosative stress (NS) and testosterone (T) concentration as a biomarker of testicular function were measured in the blood and testes. Thirty-two male Wistar rats were equally divided into four groups. A single IP dose of CIS (7 mg/kg) and protective dose of Nano-Se (2 mg/kg/day) were administered alone or in combination. The CIS-exposed rats showed a significant increase in testicular and serum LPO and ONOO level, along with a significant decrease in enzymatic antioxidants levels, diminished serum T concentration and abnormal histologic findings with impaired sperm quality associated with increased DNA damage and decreased chromatin quality. Coadministration of Nano-Se significantly improved the serum T, sperm quality, and spermatogenesis and reduced CIS-induced free radical toxic stress and spermatic DNA damage. In conclusion, the current study demonstrated that Nano-Se may be useful to prevent CIS-induced gonadotoxicity through its antioxidant potential. Highlights: ► Cisplatin (CIS) affects spermatozoa as a male reproductive toxicant. ► Effect of Nano-Se on CIS-induced spermatotoxicity was investigated. ► CIS-exposure induces oxidative sperm DNA damage

  6. Mechanistic aspects of electrodeposition of Ni–Co–SiC composite nano-coating on carbon steel

    The nucleation and early-stage growth mechanism and kinetics of electrodeposited Ni–Co–SiC composite coating on carbon steel was investigated by cyclic voltammetry, current–time transient measurements and atomic force microscopy characterization. The conventional Guglielmi's model for metal-inert particle co-deposition was modified to consider the effect of the bath electrolyte hydrodynamics on amount of nano-particles deposited in the coating. It is determined that the nucleation and early-stage growth of the coating depends on depositing overpotential. At low cathodic overpotentials, it is between an instantaneous and progressive mechanism; while at high overpotentials, it follows the instantaneous mechanism. Addition of SiC nano-particles in the bath electrolyte reduces the electrodepositing efficiency by inhibiting nucleation and growth of metallic coating. An empirical model is developed to estimate the amount of nano-particles contained in Ni–Co–SiC composite coating during pulse electrodeposition

  7. Electroless Ag coating of fly ash cenospheres using polyaniline activator

    The electroless Ag coating of fly ash cenospheres employing polyaniline activator was investigated after polyaniline activator was coated on the surfaces of the cenosphere particles by in situ chemical polymerization. The composites were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, UV-visible absorption spectroscopy, x-ray diffraction and thermogravimetric analysis (TGA). The results indicate that a small amount of polyaniline activator was deposited in a discontinuous way on the surfaces of the cenosphere particles. Due to the activation of polyaniline, relatively compact and continuous Ag layer with a thickness of about 4 μm was obtained under the given electroless plating condition. The possible interaction between polyaniline and silver ions and the mechanism of Ag deposition were also investigated by the x-ray photoelectron spectroscopy technique.

  8. Electroless Ag coating of fly ash cenospheres using polyaniline activator

    Wang Wei; Li Qin; Li Ying; Xu Hui; Zhai Jianping, E-mail: jpzhai@nju.edu.c [State Key Laboratory of Pollution Control and Resource Reuse, and School of the Environment, Nanjing University, Nanjing 210093 (China)

    2009-11-07

    The electroless Ag coating of fly ash cenospheres employing polyaniline activator was investigated after polyaniline activator was coated on the surfaces of the cenosphere particles by in situ chemical polymerization. The composites were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, UV-visible absorption spectroscopy, x-ray diffraction and thermogravimetric analysis (TGA). The results indicate that a small amount of polyaniline activator was deposited in a discontinuous way on the surfaces of the cenosphere particles. Due to the activation of polyaniline, relatively compact and continuous Ag layer with a thickness of about 4 {mu}m was obtained under the given electroless plating condition. The possible interaction between polyaniline and silver ions and the mechanism of Ag deposition were also investigated by the x-ray photoelectron spectroscopy technique.

  9. Electroless Ag coating of fly ash cenospheres using polyaniline activator

    Wang, Wei; Li, Qin; Li, Ying; Xu, Hui; Zhai, Jianping

    2009-11-01

    The electroless Ag coating of fly ash cenospheres employing polyaniline activator was investigated after polyaniline activator was coated on the surfaces of the cenosphere particles by in situ chemical polymerization. The composites were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, UV-visible absorption spectroscopy, x-ray diffraction and thermogravimetric analysis (TGA). The results indicate that a small amount of polyaniline activator was deposited in a discontinuous way on the surfaces of the cenosphere particles. Due to the activation of polyaniline, relatively compact and continuous Ag layer with a thickness of about 4 µm was obtained under the given electroless plating condition. The possible interaction between polyaniline and silver ions and the mechanism of Ag deposition were also investigated by the x-ray photoelectron spectroscopy technique.

  10. Environmentally benign heterogeneous nano-particle catalysts: synthesis, characterization and catalytic activity of 4-nitrophenol.

    Murugan, Eagambaram; Jebaranjitham, J Nimita

    2011-02-01

    Pollution free catalyst is an attractive area of current interest. The p-Aminophenol is one of the most significant catalyst, because it involves the manufacture of various pharmaceuticals. Crosslinked poly(styrene)-co-poly(4-vinylimidazole) (PSPVIM) was prepared by varying the crosslinked monomer ratio as 2% and 10% respectively. The 2 (w%) of DVB, 25 (w%) of N-VIm as functional monomer and 73 (w%) of styrene as support monomer as organic phase and gelatin, boric acid and polyvinyl alcohol as aqueous phase was used to prepare cross-linked poly(styrene)-co-poly(N-vinyl imidazole) (PVIM) beads (Type-I). Similarly, Type II beads were also prepared by fixing the 10% as a cross linking ratio (DVB). The immobilization of Ag NPs onto the PS-VIm polymer matrix was performed using AgNO3 as a metal precursor solution. The k(obs) determined from UV-Vis results, reveals that the degree of reduction of 4-nitrophenol using Type-I catalysts is more effective than Type-II catalyst due to lower immobilization of AgNPs at higher cross-linked bead matrix. It was found that on increasing the amount of catalyst i.e., type-I PS-PVIm-AgNPs, the rate constant also increases. Therefore, PS-PVIm-AgNPs (Type-I) heterogeneous catalyst is superior for the reduction of 4-NP. PMID:21485850

  11. Bactericidal activity of green tea extracts: the importance of catechin containing nano particles

    Judy Gopal; Manikandan Muthu; Diby Paul; Doo-Hwan Kim; Sechul Chun

    2016-01-01

    When we drink green tea infusion, we believe we are drinking the extract of the green tea leaves. While practically each tea bag infused in 300 mL water contains about 50 mg of suspended green tea leaf particles. What is the role of these particles in the green tea effect is the objective of this study. These particles (three different size ranges) were isolated via varying speed centrifugation and their respective inputs evaluated. Live oral bacterial samples from human volunteers have been ...

  12. Coatings.

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  13. Deformation Behavior of Nanostructured Ceramic Coatings Deposited by Thermal Plasma Spray

    Xianliang JIANG; Eric Jordan; Leon Shaw; Maurice Gell

    2004-01-01

    Al2O3-13 wt pct TiO2 coating deposited by direct current plasma spray consists of nanostructured region and microlamellae. Bend test shows that the ceramic coating can sustain some deformation without sudden failure. The deformation is achieved through the movement of nano-particles in the nanostructured region under tensile stress.

  14. Control of the Nano-Particle Weight Ratio in Stainless Steel Micro and Nano Powders by Radio Frequency Plasma Treatment

    Dong-Yeol Yang; Youngja Kim; Min Young Hur; Hae June Lee; Yong-Jin Kim; Tae-Soo Lim; Ki-Bong Kim; Sangsun Yang

    2015-01-01

    This study describes how to make stainless steel hybrid micro-nano-powders (a mixture of micro-powder and nano-powder) using an in situ one-step process via radio frequency (RF) thermal plasma treatment. Nano-particles attached to micro-powders were successfully prepared by RF thermal plasma treatment of stainless steel powder with an average size of 35 μm. The ratio of nano-powders is estimated with a two-dimensional fluid simulation that calculates the temperature profile influencing the r...

  15. Preparation of Nano-Particles (Pb,La)TiO3 Thin Films by Liquid Source Misted Chemical Deposition

    张之圣; 曾建平; 李小图

    2004-01-01

    Nano-particles lanthanum-modified lead titanate (PLT) thin films are grown on Pt/Ti/SiO2/Si substrate by liquid source misted chemical deposition (LSMCD). PLT films are deposited for 4-8 times, and then annealed at various temperature. XRD and SEM show that the prepared films have good crystallization behavior and perovskite structure. The crystallite is about 60 nm. The deposition speed is 3 nm/min. This deposition method can exactly control stoichiometry ratios, doping concentration ratio and thickness of PLT thin films. The best annealing process is to bake at 300 ℃ for 10 min and anneal at 600 ℃ for 1 h.

  16. Selective imaging of nano-particle contrast agents by a single-shot x-ray diffraction technique.

    Stein, Ashley F; Ilavsky, Jan; Kopace, Rael; Bennett, Eric E; Wen, Han

    2010-06-01

    Iron oxide nano-particles have very different x-ray diffraction properties from tissue. They can be clearly visualized against suppressed tissue background in a single-shot x-ray diffraction imaging technique. This technique is able to acquire both diffraction and absorption images from a single grating-modulated projection image through analysis in the spatial frequency domain. We describe the use of two orthogonal transmission gratings to selectively retain diffraction signal from iron oxide particles that are larger than a threshold size, while eliminating the background signal from soft tissue and bone. This approach should help the tracking of functionalized particles in cell labeling and targeted therapy. PMID:20588456

  17. Development of a High-performance Fluorpolymer Electret Mixed with Nano-particles and Its Application to Vibration Energy Harvesting

    We have been developing small power generation device of capacitance-type to be converted to electrical energy vibration energy using an electret. In this Study, dielectric nanoparticles were mixed with an electret made of fluorocarbon polymer. As a result, implanted charge density of the electret was successfully enhanced thanks to the mixing of particles. A small sized vibration energy harvester (VEH) was fabricated using the fluorocarbon mixed with dielectric nano-particles. As a result of applying vibration (20 Hz, 0.65 G) to the fabricated VEH, The maximum generated power of approximately 50 μW was obtained

  18. Influence of embedding Cu nano-particles into a Cu/SiO2/Pt structure on its resistive switching

    LIU, CHIH-YI; Huang, Jyun-Jie; Lai, Chun-Hung; Lin, Chao-Han

    2013-01-01

    Cu nano-particles (Cu-NPs) were embedded into the SiO2 layer of a Cu/SiO2/Pt structure to examine their influence on resistive switching characteristics. The device showed a reversible resistive switching behavior, which was due to the formation and rupture of a Cu-conducting filament with an electrochemical reaction. The Cu-NPs enhanced the local electric field within the SiO2 layer, which caused a decrease in the forming voltage. During successive switching processes, the Cu-NP was partiall...

  19. An investigation of the dependence of the average value of anisotropy constant of nano-particle systems on packing friction.

    Fannin, Paul C.; Coffey, William T.

    2000-03-01

    Measurements are presented of the complex magnetic susceptibility,\\chi (ω) = \\chi' (ω )- i\\chi'' (ω ), of a number of colloidal suspensions of nano-particles with different packing fractions, over the frequency range 10kHz to 18kHz. The magnetic field dependence of the average particle anisotropy constant, K, for magnetic fluids samples of magnetite in isopar M for seventeen values of polarising field, H, in the approximate range 0 to 100,000 A/m are presented and examined.

  20. Precursor-Less Coating of Nanoparticles in the Gas Phase

    Pfeiffer, T.V.; Kedia, P.; Messing, M.E.; Valvo, M.; Schmidt-Ott, A.

    2015-01-01

    This article introduces a continuous, gas-phase method for depositing thin metallic coatings onto (nano)particles using a type of physical vapor deposition (PVD) at ambient pressure and temperature. An aerosol of core particles is mixed with a metal vapor cloud formed by spark ablation by passing th

  1. CEMS and XRD studies on changing shape of iron nano-particles by irradiation of Au ions of Fe-implanted Al2O3 granular layer

    In order to observe an inverse Ostwald ripening of Fe nano-particles in Fe-implanted Al2O3 granular layers, 3 MeV Au ions were irradiated to Fe nano-particles in these layers with doses of 0.5x and 1.5x1016 ions/cm2. It was found by Conversion Electron Mossbauer Spectroscopy (CEMS) that the inverse Ostwald ripening occurred by fractions of percentages and the magnetic anisotropy of Fe nano-particles was induced to the direction of Au ion beam, i.e. perpendicular to the granular plane. The average crystallite diameters of Fe nano-particles for Au ions unirradiated and irradiated samples were measured using Scherrer's formula from FWHM of Fe (110) X-ray Diffraction (XRD) patterns obtained by 2θ and 2θ/θ methods. It was confirmed that the average crystallite diameters of Fe nano-particles in Fe-implanted Al2O3 granular layers were extended by Au ions irradiation. (author)

  2. Microstructure and superconducting properties in air-properties GdBa2Cu3O7-δ superconductor with the additives of nano particles

    It is regarded as an effective method to improve the flux pinning performance by the additives of the secondary phase inclusions in nano sizes into high temperature superconductor bulks. We prepared the single domain superconductor GdBa2Gi3O7-δ bulks with variable additions of (ZrO2+SnO2+ZnO) nano-particles in air by using top seed melt-textured growth process. The effect of nano-particle additions on superconductivity properties has been investigated. An enhancement of the critical current JC in low and intermediate field at 77K and trapped field was discovered by the additions of the nano-particles. At the same time, the superconductor transition temperature, TC, slightly decreases from 93.5K to 91.5K The microstructure measurements show that the nano-particle inclusions enhance with the increase of the content of nano-particles, which may illuminate the JC enhancement of the specimens.

  3. Antibacterial Activity of Polymer Coated Cerium Oxide Nanoparticles

    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...

  4. Microstructure and mechanical property of in-situ nano-particle strengthened ferritic steel by novel internal oxidation

    A novel route of fabricating nano-particles strengthened ferrite steel was investigated in this study. Rather than by externally adding nano-oxide powders, we adopted the endogenous method of controlling oxide reaction and solute concentration distribution in the process of deoxidization to obtain a high density of in-situ nano-oxide particles homogeneously dispersed in the ferrite matrix in melt. The microstructure and tensile properties of these materials had been investigated to clarify the interrelation between the composition, microstructure and mechanical properties. Transmission electron microscopy (TEM) analysis indicated that these nano-particles were titanium oxides, which have a positive effect on optimizing inclusions and refining grains. Tensile tests revealed that these titanium oxide particles play an important role in increasing the yield strength. The steel has yield strength of 711 MPa, approximately three times higher than that of conventional plain carbon structural steels, and its ultimate tensile strength reaches 810 MPa with an elongation-to-failure value of 22%. Precipitation hardening and grain refinement hardening are the dominant factors responsible for yield strength increasing in this steel

  5. Synthesis of Uranium-di-Oxide nano-particles by pulsed laser ablation in ethanol and their characterisation

    The importance of actinide based nano-structures is well known in the area of biology, nuclear medicine, and nuclear industry. Pulsed laser ablation in liquid is recognised as an attractive technique for production of nano-structures of different metals and metal oxides with high purity. In this paper, we report synthesis of uranium-di-oxide nano particles by pulsed laser ablation in ethanol. The second harmonic emission of an electro- optically Q-switched nano-second Nd-YAG laser was used as the coherent source here. The structural and optical properties of the fabricated Uranium-di-oxide nano- particles were investigated by XRD, SEM, TEM, EDX and UV- Vis-NIR spectrophotometry. The mean size of the particles was found to be dependent on the laser ablation parameters. XRD and TEM analysis confirmed the phase of the synthesised material as pure crystalline Uranium-di- oxide with Face Centred Cubic structure. UV- Vis- NIR absorption spectra of the colloidal solution show high absorption in the UV regime. (author)

  6. Optical Properties of Zinc Oxide Nano-particles Embedded in Dielectric Medium for UV region: Numerical Simulation

    Zinc oxide nano-particles have been used by cosmetic industry for many years because they are extensively used as agents to attenuate (absorb and/or scatter) the ultraviolet radiation. In the most UV-attenuating agent is formulated in which the metal oxide nano-particles are incorporated into liquid media or polymer media are manufactured, such as sunscreens and skin care cosmetics. In this paper we study the wavelength dependence on the particle size (reff = 10-100 nm) by solving the scattering problem of hexagonal ZnO particle for different shapes (plate, equal ratio, column) using the discrete dipole approximation method to find the absorption, scattering, and extinction efficiencies for the UV region (30-400 nm). A new modified hexagonal shape is introduced to determine the scattering problem and it is assumed in this study that the wavelength is comparable to the particle size. From these results, we conclude that the optimum particle radius to block the UV radiation is between reff = 40-80 nm

  7. Enhancement of photo-response via surface plasmon resonance induced by Ag nano-particles embedded in ZnO

    Li, Gaoming; Zhang, Jingwen; Chen, Guangde; Ye, Honggang; Duan, Xiangyang; Hou, Xun

    2016-09-01

    Surface plasmon resonance can be exploited to improve the performance of the photodetectors. However, it may cause the increase of dark current as a side effect. The enhancement of responsivity is highly dependent on the device structure involving SPR and the situations of the metal nano-particles. In this paper, we reported the responsivity enhancement of the ZnO UV detectors with SPR based on a structure in which Ag nano-particles are embedded in ZnO film, without the apparent increase of dark current. We found that the characteristic wavelength for SPR absorption is 380 nm, well predicted by Mie theory. And the spectral responsivity peak value increases from 472 mA/W to 10.522 A/W, by 22.3 times. The good matching between enhancement spectra and SPR absorption spectra confirms that the responsivity enhancement is resulted from SPR. Our results are of great importance in improving the photodetectors based on SPR effects, which may be widely used in light detection.

  8. The effect of acid-base clustering and ions on the growth of atmospheric nano-particles.

    Lehtipalo, Katrianne; Rondo, Linda; Kontkanen, Jenni; Schobesberger, Siegfried; Jokinen, Tuija; Sarnela, Nina; Kürten, Andreas; Ehrhart, Sebastian; Franchin, Alessandro; Nieminen, Tuomo; Riccobono, Francesco; Sipilä, Mikko; Yli-Juuti, Taina; Duplissy, Jonathan; Adamov, Alexey; Ahlm, Lars; Almeida, João; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; Dommen, Josef; Downard, Andrew J; Dunne, Eimear M; Flagan, Richard C; Guida, Roberto; Hakala, Jani; Hansel, Armin; Jud, Werner; Kangasluoma, Juha; Kerminen, Veli-Matti; Keskinen, Helmi; Kim, Jaeseok; Kirkby, Jasper; Kupc, Agnieszka; Kupiainen-Määttä, Oona; Laaksonen, Ari; Lawler, Michael J; Leiminger, Markus; Mathot, Serge; Olenius, Tinja; Ortega, Ismael K; Onnela, Antti; Petäjä, Tuukka; Praplan, Arnaud; Rissanen, Matti P; Ruuskanen, Taina; Santos, Filipe D; Schallhart, Simon; Schnitzhofer, Ralf; Simon, Mario; Smith, James N; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Tomé, António; Vaattovaara, Petri; Vehkamäki, Hanna; Vrtala, Aron E; Wagner, Paul E; Williamson, Christina; Wimmer, Daniela; Winkler, Paul M; Virtanen, Annele; Donahue, Neil M; Carslaw, Kenneth S; Baltensperger, Urs; Riipinen, Ilona; Curtius, Joachim; Worsnop, Douglas R; Kulmala, Markku

    2016-01-01

    The growth of freshly formed aerosol particles can be the bottleneck in their survival to cloud condensation nuclei. It is therefore crucial to understand how particles grow in the atmosphere. Insufficient experimental data has impeded a profound understanding of nano-particle growth under atmospheric conditions. Here we study nano-particle growth in the CLOUD (Cosmics Leaving OUtdoors Droplets) chamber, starting from the formation of molecular clusters. We present measured growth rates at sub-3 nm sizes with different atmospherically relevant concentrations of sulphuric acid, water, ammonia and dimethylamine. We find that atmospheric ions and small acid-base clusters, which are not generally accounted for in the measurement of sulphuric acid vapour, can participate in the growth process, leading to enhanced growth rates. The availability of compounds capable of stabilizing sulphuric acid clusters governs the magnitude of these effects and thus the exact growth mechanism. We bring these observations into a coherent framework and discuss their significance in the atmosphere. PMID:27197574

  9. The effect of acid–base clustering and ions on the growth of atmospheric nano-particles

    Lehtipalo, Katrianne; Rondo, Linda; Kontkanen, Jenni; Schobesberger, Siegfried; Jokinen, Tuija; Sarnela, Nina; Kürten, Andreas; Ehrhart, Sebastian; Franchin, Alessandro; Nieminen, Tuomo; Riccobono, Francesco; Sipilä, Mikko; Yli-Juuti, Taina; Duplissy, Jonathan; Adamov, Alexey; Ahlm, Lars; Almeida, João; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; Dommen, Josef; Downard, Andrew J.; Dunne, Eimear M.; Flagan, Richard C.; Guida, Roberto; Hakala, Jani; Hansel, Armin; Jud, Werner; Kangasluoma, Juha; Kerminen, Veli-Matti; Keskinen, Helmi; Kim, Jaeseok; Kirkby, Jasper; Kupc, Agnieszka; Kupiainen-Määttä, Oona; Laaksonen, Ari; Lawler, Michael J.; Leiminger, Markus; Mathot, Serge; Olenius, Tinja; Ortega, Ismael K.; Onnela, Antti; Petäjä, Tuukka; Praplan, Arnaud; Rissanen, Matti P.; Ruuskanen, Taina; Santos, Filipe D.; Schallhart, Simon; Schnitzhofer, Ralf; Simon, Mario; Smith, James N.; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Tomé, António; Vaattovaara, Petri; Vehkamäki, Hanna; Vrtala, Aron E.; Wagner, Paul E.; Williamson, Christina; Wimmer, Daniela; Winkler, Paul M.; Virtanen, Annele; Donahue, Neil M.; Carslaw, Kenneth S.; Baltensperger, Urs; Riipinen, Ilona; Curtius, Joachim; Worsnop, Douglas R.; Kulmala, Markku

    2016-01-01

    The growth of freshly formed aerosol particles can be the bottleneck in their survival to cloud condensation nuclei. It is therefore crucial to understand how particles grow in the atmosphere. Insufficient experimental data has impeded a profound understanding of nano-particle growth under atmospheric conditions. Here we study nano-particle growth in the CLOUD (Cosmics Leaving OUtdoors Droplets) chamber, starting from the formation of molecular clusters. We present measured growth rates at sub-3 nm sizes with different atmospherically relevant concentrations of sulphuric acid, water, ammonia and dimethylamine. We find that atmospheric ions and small acid-base clusters, which are not generally accounted for in the measurement of sulphuric acid vapour, can participate in the growth process, leading to enhanced growth rates. The availability of compounds capable of stabilizing sulphuric acid clusters governs the magnitude of these effects and thus the exact growth mechanism. We bring these observations into a coherent framework and discuss their significance in the atmosphere. PMID:27197574

  10. Dual layer hollow fiber PVDF ultra-filtration membranes containing Ag nano-particle loaded zeolite with longer term anti-bacterial capacity in salt water.

    Shi, Huyan; Xue, Lixin; Gao, Ailin; Zhou, Qingbo

    2016-01-01

    Dual layer polyvinylidene fluoride (PVDF), antibacterial, hollow fiber, ultra-filtration composite membranes with antibacterial particles (silver (Ag) nano-particles loaded zeolite (Z-Ag)) in the outer layer were prepared with high water flux and desired pore sizes. The amounts of Ag(+) released from the composite membranes, freshly made and stored in water and salt solution, were measured. The result indicated that dual layer PVDF antibacterial hollow fiber containing Z-Ag (M-1-Ag) still possessed the ability of continuous release of Ag(+) even after exposure to water with high ionic content, showing a longer term resistance to bacterial adhesion and antibacterial activity than membrane doped with Z-Ag(+) (M-1). Results from an anti-adhesion and bacteria killing test with Escherichia coli supported that the antibacterial efficiency of dual hollow fiber PVDF membranes with Z-Ag was much higher than those with Z-Ag(+) after long time storage in water or exposure to phosphate buffered saline (PBS) solution. This novel hollow fiber membrane may find applications in constructing sea water pretreatment devices with long term antifouling capability for the desalination processes. PMID:27148717

  11. Elaboration of titanium nitride coatings by activated reactive evaporation

    As titanium nitride is a very interesting and promising material for the protection against wear and corrosion of metals and alloys with a low fusion point, and notably steels, this research thesis reports the study of the elaboration of a TiN coating by activated reactive evaporation. In a first part, the author describes deposition processes based on evaporation and their characteristics. He explains the choice of the studied process. He discusses published data and results related to the titanium-nitrogen system. He describes the apparatus and reports the operation mode adjustment, and reports the study of the influence of operating conditions (substrate temperature, nitrogen pressure, evaporation rate, possible use of a discharge) on growth kinetics and on coating properties. A reaction mechanism is then proposed to describe and explain the obtained results

  12. Adaptive neuro-fuzzy inference system (ANFIS) to predict CI engine parameters fueled with nano-particles additive to diesel fuel

    Ghanbari, M.; Najafi, G.; Ghobadian, B.; Mamat, R.; Noor, M. M.; Moosavian, A.

    2015-12-01

    This paper studies the use of adaptive neuro-fuzzy inference system (ANFIS) to predict the performance parameters and exhaust emissions of a diesel engine operating on nanodiesel blended fuels. In order to predict the engine parameters, the whole experimental data were randomly divided into training and testing data. For ANFIS modelling, Gaussian curve membership function (gaussmf) and 200 training epochs (iteration) were found to be optimum choices for training process. The results demonstrate that ANFIS is capable of predicting the diesel engine performance and emissions. In the experimental step, Carbon nano tubes (CNT) (40, 80 and 120 ppm) and nano silver particles (40, 80 and 120 ppm) with nanostructure were prepared and added as additive to the diesel fuel. Six cylinders, four-stroke diesel engine was fuelled with these new blended fuels and operated at different engine speeds. Experimental test results indicated the fact that adding nano particles to diesel fuel, increased diesel engine power and torque output. For nano-diesel it was found that the brake specific fuel consumption (bsfc) was decreased compared to the net diesel fuel. The results proved that with increase of nano particles concentrations (from 40 ppm to 120 ppm) in diesel fuel, CO2 emission increased. CO emission in diesel fuel with nano-particles was lower significantly compared to pure diesel fuel. UHC emission with silver nano-diesel blended fuel decreased while with fuels that contains CNT nano particles increased. The trend of NOx emission was inverse compared to the UHC emission. With adding nano particles to the blended fuels, NOx increased compared to the net diesel fuel. The tests revealed that silver & CNT nano particles can be used as additive in diesel fuel to improve combustion of the fuel and reduce the exhaust emissions significantly.

  13. Preparation of ZrO2 nano-particles by the hydrolysis of ZrOCl2 solution in the reverse micelles

    Chensha Li; Tongxiang Liang; Tianyong Luo

    2006-01-01

    Zirconia nano-particles have been produced by the hydrolysis of ZrOGl2 solution in the reverse micelles of a liquid-liquid two-phase system, in which sodium bis(2-ethylhexyl) sulfosuccinite (AOT) and toluene were chosen as the surfactant and organic phase, respectively. The reverse micelles prevented the aggregation of primary particles and reduced the diameters of zirconia nanoparticles. Superfine zirconia powders soft-aggregated by the zirconia nano-particles were obtained. The diameters of zirconia nanoparticles were influenced by the quantity of the surfactant.

  14. Endocytosis of activated receptors and clathrin-coated pit formation: deciphering the chicken or egg relationship

    1996-01-01

    The fundamental mechanisms by which receptors once targeted for endocytosis are found in coated pits is an important yet unresolved question. Specifically, are activated receptors simply trapped on encountering preexisting coated pits, subsequently being rapidly internalized? Or do the receptors themselves, by active recruitment, gather soluble coat and cytosolic components and initiate the rapid assembly of new coated pits that then mediate their internalization? To explore this question, we...

  15. Chiroptical activity in colloidal quantum dots coated with achiral ligands.

    Melnikau, Dzmitry; Savateeva, Diana; Gaponik, Nikolai; Govorov, Alexander O; Rakovich, Yury P

    2016-01-25

    We studied the chiroptical properties of colloidal solution of CdSe and CdSe/ZnS quantum dots (QDs) with a cubic lattice structure which were initially prepared without use of any chiral molecules and coated with achiral ligands. We demonstrate circular dichroism (CD) activity around first and second excitonic transition of these CdSe based nanocrystals. We consider that this chiroptical activity is caused by imbalance in racemic mixtures of QDs between the left and right handed nanoparticles, which appears as a result of the formation of various defects or incorporation of impurities into crystallographic structure during their synthesis. We demonstrate that optical activity of colloidal solution of CdSe QDs with achiral ligands weakly depends on the QDs size and number of ZnS monolayers, but does not depend on the nature of achiral ligands or polarity of the solution. PMID:26832599

  16. Effect of the Addition MgO Nano Particle to Mechanical Properties and Microstructure of ZTA Ceramic Composite

    The mechanical properties and microstructure of zirconia-toughened alumina ceramic composite doped with nano particle of MgO is investigated. The nano-MgO weight percent was varied from 0 wt% to 1.3 wt%. Each batch of composition was mixed using ultrasonic cleaning and mechanical stirrer, uniaxially pressed and sintered at 1600 degree Celsius for 4 h in pressureless conditions. Analysis of bulk density, Vickers hardness, fracture toughness and microstructural observation has been carried out. Results of Vickers hardness increased linearly with addition of more nano-MgO until a certain composition. Maximum Vickers hardness obtained was 1740HV with 1.1 wt % MgO. (author)

  17. Microstructure and mechanical properties of aluminum alloy matrix composite reinforced with nano-particle MgO

    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.

  18. Study of chemically synthesized ZnO nano particles under a bio template using radioactive ion beam

    This is a project proposal to study nano sized semiconductor ZnO system, useful in biology and medicinal purposes, using radioactive ion beam from ISOLDE. Doping of the nano particles with Cu, Cd and Ga ions (in their variable valancy states) are expected to impart changes in the electrical structure and properties in the said system under study. The morphological changes, chemical environment, micro structure, electrical and optical properties of the nano size particles of ZnO system (developed under a bio template of folic acid) after the interaction with radioactive ion beam will be studied. The provision of perturbed angular correlation (PAC) study with respect to the changes in chemical environment, where ever possible will be attempted.

  19. Electrical memory features of ferromagnetic CoFeAlSi nano-particles embedded in metal-oxide-semiconductor matrix

    Lee, Ja Bin [Novel Functional Materials and Devices Laboratory, Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Ki Woong [Semiconductor R and D Center, Samsung Electronics Co. Ltd, Gyeonggi-Do 445-701 (Korea, Republic of); Lee, Jun Seok; An, Gwang Guk [Novel Functional Materials and Devices Laboratory, Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of); Hong, Jin Pyo, E-mail: jphong@hanyang.ac.kr [Novel Functional Materials and Devices Laboratory, Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2011-07-01

    Half-metallic Heusler material Co{sub 2}FeAl{sub 0.5}Si{sub 0.5} (CFAS) nano-particles (NPs) embedded in metal-oxide-semiconductor (MOS) structures with thin HfO{sub 2} tunneling and MgO control oxides were investigated. The CFAS NPs were prepared by rapid thermal annealing. The formation of well-controlled CFAS NPs on thin HfO{sub 2} tunneling oxide was confirmed by atomic force microscopy (AFM). Memory characteristics of CFAS NPs in MOS devices exhibited a large memory window of 4.65 V, as well as good retention and endurance times of 10{sup 5} cycles and 10{sup 9} s, respectively, demonstrating the potential of CFAS NPs as promising candidates for use in charge storage.

  20. Optically sensitive devices based on Pt nano particles fabricated by atomic layer deposition and embedded in a dielectric stack

    Mikhelashvili, V.; Padmanabhan, R.; Meyler, B.; Yofis, S.; Atiya, G.; Cohen-Hyams, Z.; Weindling, S.; Ankonina, G.; Salzman, J.; Kaplan, W. D.; Eisenstein, G.

    2015-10-01

    We report a series of metal insulator semiconductor devices with embedded Pt nano particles (NPs) fabricated using a low temperature atomic layer deposition process. Optically sensitive nonvolatile memory cells as well as optical sensors: (i) varactors, whose capacitance-voltage characteristics, nonlinearity, and peak capacitance are strongly dependent on illumination intensity; (ii) highly linear photo detectors whose responsivity is enhanced due to the Pt NPs. Both single devices and back to back pairs of diodes were used. The different configurations enable a variety of functionalities with many potential applications in biomedical sensing, environmental surveying, simple imagers for consumer electronics and military uses. The simplicity and planar configuration of the proposed devices makes them suitable for standard CMOS fabrication technology.

  1. Using Silver Nano-Particle Ink in Electrode Fabrication of High Frequency Copolymer Ultrasonic Transducers: Modeling and Experimental Investigation

    Adit Decharat

    2015-04-01

    Full Text Available High frequency polymer-based ultrasonic transducers are produced with electrodes thicknesses typical for printed electrodes obtained from silver (Ag nano-particle inks. An analytical three-port network is used to study the acoustic effects imposed by a thick electrode in a typical layered transducer configuration. Results from the network model are compared to experimental findings for the implemented transducer configuration, to obtain a better understanding of acoustical effects caused by the additional printed mass loading. The proposed investigation might be supportive of identification of suitable electrode-depositing methods. It is also believed to be useful as a feasibility study for printed Ag-based electrodes in high frequency transducers, which may reduce both the cost and production complexity of these devices.

  2. Optically sensitive devices based on Pt nano particles fabricated by atomic layer deposition and embedded in a dielectric stack

    We report a series of metal insulator semiconductor devices with embedded Pt nano particles (NPs) fabricated using a low temperature atomic layer deposition process. Optically sensitive nonvolatile memory cells as well as optical sensors: (i) varactors, whose capacitance-voltage characteristics, nonlinearity, and peak capacitance are strongly dependent on illumination intensity; (ii) highly linear photo detectors whose responsivity is enhanced due to the Pt NPs. Both single devices and back to back pairs of diodes were used. The different configurations enable a variety of functionalities with many potential applications in biomedical sensing, environmental surveying, simple imagers for consumer electronics and military uses. The simplicity and planar configuration of the proposed devices makes them suitable for standard CMOS fabrication technology

  3. Magnetic behaviour of nano-particles of Fe2.9Zn0.1O4

    Subhash Chander; Sudhish Kumar; Anjali Krishnamurthy; Bipin K Srivastava; V K Aswal

    2003-09-01

    DC magnetization measurements are reported in the temperature range 20–300 K on a poly-disperse nano-particle sample of the spinel ferrite Fe2.9Zn0.1O4 with a log-normal size distribution of median diameter 43.6 Å and standard deviation 0.58. Outside a core of ordered spins, moments in surface layer are disordered. Results also show some similarities with conventional spin glasses. Blocking temperature exhibits a near linear variation with two-third power of the applied magnetic field and magnetization evolves nearly linearly with logarithm of time . Magnetic anisotropy has been estimated by analysing the $M-\\log t$ curve. Anisotropy values show a large increase over that of bulk particle samples. Major contribution to this enhancement comes from the disordered surface spins.

  4. The effect of metal nano particle on optical absorption coefficient of multi-layer spherical quantum dot

    Zamani, N.; Keshavarz, A.; Nadgaran, H.

    2016-06-01

    In this paper, we investigate the optical absorption coefficient of hybrid structure consisting of metal nano particle (MNP) coupled to multi-layer spherical quantum dot (MSQD). Energy eigenvalues and eigenfunctions of Schrödinger equation in this structure are obtained by using numerical solution (by the fourth-order Runge-Kutta method). The effect of MNP in the vicinity of MSQD is calculated by considering local field theory. Then the variation of optical absorption coefficient hybrid structure is calculated. The results show that the presence of MNP near MSQD enhances the optical absorption coefficient. Also, by changing the distance between MNP and MSQD and radius of MNP, variation of optical absorption coefficient and refractive index changes are introduced.

  5. Role of the Initial Formation of the Iron Nano-Particles in the Multi-Walled Carbon Nanotubes Growth Process

    Leszek Stobinski; Hong-Ming Lin

    2004-01-01

    Careful preparation of the iron nano-particle catalyst for carbon nanotubes (CNTs) fabrication has crucial importance for initial growth of multi-wall carbon-nanotubes (MWCNTs). Thin iron layer was thermally deposited in a high vacuum onto the surface of the SiO2/Si wafer at about 300 K. The sample was heated up to 700℃ in a hydrogen atmosphere, and then the sample was heated once again at750℃ in ethylene atmosphere. After hydrogen treatment continuous Fe layer was changed into many well separated Fe nano-peaks. AFM, SEM and HR-TEM studies of deposited MWCNTs allow us to propose a growth mechanism for long, straight MWCNTs.

  6. Degradation behavior of n-MAO/EPD bio-ceramic composite coatings on magnesium alloy in simulated body fluid

    Highlights: • A bio-ceramic n-MAO/EPD coating was prepared by combined MAO and EPD technique. • The precipitates of Ca/P compound are formed on the surface samples during immersion. • The n-MAO/EPD coating with HA dense structure has a favorable anti-corrosion effect. • Two degradation mechanism models for the n-MAO and n-MAO/EPD coating were proposed. - Abstract: The bio-ceramic composite coatings have been fabricated on ZK60 magnesium (Mg) alloy to improve its bio-corrosion resistance in a simulated body fluid (SBF). Firstly, micro-arc oxidation coatings (n-MAO coating) with the addition of zirconium oxide (ZrO2) and cerium oxide (CeO2) nano-particles were prepared by MAO technique on ZK60Mg alloy in alkaline electrolyte. Secondly, nano-hydroxyapatite (HA) was deposited on the surface of n-MAO coatings by using electrophoretic deposition (EPD) technique. The degradation behavior of the coated samples was investigated by means of immersion tests and electrochemical impedance spectroscopy (EIS) in the SBF at 36.5 ± 0.5 °C. The variation of phase composition, surface and cross-section morphology of coatings at different immersion stages were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results showed that the precipitation layer with biological activity formed on the surface of coated samples during the SBF immersion, which can inhibit Mg alloys from degrading effectively. The n-MAO/EPD composite coating with HA dense structure has a favorable anti-corrosion effect compared to the n-MAO coating. Degradation mechanism model of the corrosion process at different corrosion stages for two kinds of coatings were proposed. The long-term corrosion protection of the n-MAO/EPD composite coating was governed significantly by the synergistic effect of phase composition stability and micro structural integrity

  7. Degradation behavior of n-MAO/EPD bio-ceramic composite coatings on magnesium alloy in simulated body fluid

    Xiong, Ying, E-mail: yxiong@zjut.edu.cn [College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Lu, Chao [College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Wang, Chao; Song, Renguo [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China)

    2015-03-15

    Highlights: • A bio-ceramic n-MAO/EPD coating was prepared by combined MAO and EPD technique. • The precipitates of Ca/P compound are formed on the surface samples during immersion. • The n-MAO/EPD coating with HA dense structure has a favorable anti-corrosion effect. • Two degradation mechanism models for the n-MAO and n-MAO/EPD coating were proposed. - Abstract: The bio-ceramic composite coatings have been fabricated on ZK60 magnesium (Mg) alloy to improve its bio-corrosion resistance in a simulated body fluid (SBF). Firstly, micro-arc oxidation coatings (n-MAO coating) with the addition of zirconium oxide (ZrO{sub 2}) and cerium oxide (CeO{sub 2}) nano-particles were prepared by MAO technique on ZK60Mg alloy in alkaline electrolyte. Secondly, nano-hydroxyapatite (HA) was deposited on the surface of n-MAO coatings by using electrophoretic deposition (EPD) technique. The degradation behavior of the coated samples was investigated by means of immersion tests and electrochemical impedance spectroscopy (EIS) in the SBF at 36.5 ± 0.5 °C. The variation of phase composition, surface and cross-section morphology of coatings at different immersion stages were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results showed that the precipitation layer with biological activity formed on the surface of coated samples during the SBF immersion, which can inhibit Mg alloys from degrading effectively. The n-MAO/EPD composite coating with HA dense structure has a favorable anti-corrosion effect compared to the n-MAO coating. Degradation mechanism model of the corrosion process at different corrosion stages for two kinds of coatings were proposed. The long-term corrosion protection of the n-MAO/EPD composite coating was governed significantly by the synergistic effect of phase composition stability and micro structural integrity.

  8. Optical micro resonance based sensor schemes for detection and identification of nano particles and biological agents in situ

    Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Schweiger, Gustav; Ostendorf, Andreas

    2010-05-01

    A novel emerging technique for the label-free analysis of nano particles including biomolecules using optical micro cavity resonance is being developed. Various schemes based on a mechanically fixed microspheres as well as microspheres melted by laser on the tip of a standard single mode fiber have been investigated to make further development for microbial application. Water solutions of ethanol, HCl, glucose, vitamin C and biotin have been used to test refractive index changes by monitoring the magnitude of the whispering gallery modes spectral shift. Particular efforts were made for effective fixing of the micro spheres in the water flow, an optimal geometry for micro resonance observation and material of microsphere the most appropriate for microbial application. Optical resonance in free micro spheres from PMMA fixed in micro channels produced by photolithography has been observed under the laser power of less then 1 microwatt. Resonance shifts of C reactive protein water solutions as well as albumin solutions in pure water and with HCl modelling blood have been investigated. Introducing controlled amount of glass gel nano particles into sensor microsphere surrounding were accompanied by both correlative resonance shift (400 nm in diameter) and total reconstruct of resonance spectra (57 nm in diameter). Developed schemes have been demonstrated to be a promising technology platform for sensitive, lab-on-chip type sensor of diagnostic tools for different biological molecules, e.g. proteins, oligonucleotides, oligosaccharides, lipids, small molecules, viral particles, cells as well as in different experimental contexts e.g. proteomics, genomics, drug discovery, and membrane studies.

  9. Study of Gel Growth Cobalt (II Oxalate Crystals as Precursor of Co3O4 Nano Particles

    Yuniar Ponco Prananto

    2013-03-01

    Full Text Available Crystal growth of cobalt (II oxalate in silica gel at room temperature as precursor of Co3O4 nano particles has been studied. Specifically, this project is focusing on the use of two different reaction tube types toward crystallization of cobalt (II oxalate in gel. The gel was prepared at pH 5 by reacting sodium metasilicate solution with dilute nitric acid (for U-tube and oxalic acid (for straight tube, with gelling time of 4 days and crystal growth time of 8 (for straight tube and 12 (for U-tube weeks. Result shows that pink crystalline powder was directly formed using straight tube method. The use of different solvents in straight tube method affects crystallization and could delay direct precipitation of the product. In contrast, bigger and better shape of red block crystal was yielded from U-tube method; however, longer growth time was needed. FTIR studies suggest that both growth method produces identical compound of hydrated cobalt (II oxalate. © 2013 BCREC UNDIP. All rights reservedReceived: 25th October 2012; Revised: 30th November 2012; Accepted: 5th December 2012[How to Cite: Y.P. Prananto, M.M. Khunur, D.T. Wahyuni, R.A. Shobirin, Y.R. Nata, E. Riskah, (2013. Study of Gel Growth Cobalt (II Oxalate Crystals as Precursor of Co3O4 Nano Particles. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (3: 198-204. (doi:10.9767/bcrec.7.3.4066.198-204][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.7.3.4066.198-204 ] View in  |

  10. Electroless Ni-Co-P Coating of Cenospheres Using Ag(NH3)2+ Activator

    ZENG Ai-xiang; XIONG Wei-hao

    2004-01-01

    Electroless Ni-Co-P-coating of fly-ash cenosphere particles is demonstrated in the present investigation. The Electroless Ni-Co-P-coating process is modified by replacing the conventional sensitization and activation steps with only using activation step with Ag(NH3)2+ activator. The cenospheres are characterized by scanning electron microscope (SEM),energy dispersive spectroscopy (EDX), X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS)during and after the coating process. Relatively uniform coating is obtained under the given coating conditions. The possible mechanism of electroless Ni-Co-P-coating of cenospheres utilizing Ag(NH3)2+ activator is suggested. The low density Ni-Co-P coated cenospheres may be utilized for manufacturing conducting polymers for EMI-shielding application and microwave absorbing materials.

  11. Preparation of Silver Nano-Particles and Use as a Material for Water Sterilization

    Tran Hong Con

    2011-01-01

    Full Text Available High dispersed nanodimensional silver metal (nanosilver solution of concentration ranging from 40 to 400 mg/L was prepared from silver nitrate in water media with and without dispersing reagent. The reduction process was initiated by ammonium hydroxide and glucose was used as a reductive reagent. The nanosilver solution was characterized by color changing from light-yellow to yellow, brown, red-brown, brown-green, dark-green, blue, dark-blue and those were depending on silver concentration and dimension of silver metal particles. The nanosilver solution was possibly used as a direct sterilizing reagent or coating on calcinated laterite grains to create sterilizing material in bacterial removing filter. Direct sterilization ability of nanosilver solution and nanosilver coated material was investigated. The results showed that with 10 ppb nanosilver in supplied water, all bacteria will be removed within 25–30 min. 10 mm thick layer of silica gel or 20 mm of calcinated laterite coated nanosilver could remove all bacteria in water flowed though with maximum flow rate of 100 L.m2/min. Moreover, sterilizing material was nontoxic and applicable for drinking water production.

  12. A two-dimensional nodal model with turbulent effects for the synthesis of Si nano-particles by inductively coupled thermal plasmas

    Nano-particle synthesis by means of inductively coupled plasma torches is a material process of large technological interest. Numerous parameters are involved in the optimization of this process; hence the development of numerical models for the prediction of thermal and magneto-fluid dynamics fields, precursor powder trajectories and thermal history, as well as nano-particle formation and growth, is necessary for the up-scaling of these devices from laboratory batch production to an industrial continuous process. In this work, a two-dimensional (2D) discrete-type model (nodal model) for the analysis of nano-powder nucleation and growth is presented, taking into account convection, diffusion and turbulent effects on particle formation. Discrete-type models feature high precision and reveal a great deal of information useful for clarifying the nano-particle formation process. Using Si as the precursor material, 2D simulations of a nano-particle synthesis RF plasma apparatus with a reaction chamber are carried out. Good agreement is found when comparing results obtained with this model with those coming from a well-established nucleation-coupled moment method. Moreover, the extended amount of obtainable information that characterizes the nodal model is underlined. (paper)

  13. Control of Partial Coalescence of Self-Assembled Metal Nano-Particles across Lyotropic Liquid Crystals Templates towards Long Range Meso-Porous Metal Frameworks Design

    Ludovic F. Dumée

    2015-10-01

    Full Text Available The formation of purely metallic meso-porous metal thin films by partial interface coalescence of self-assembled metal nano-particles across aqueous solutions of Pluronics triblock lyotropic liquid crystals is demonstrated for the first time. Small angle X-ray scattering was used to study the influence of the thin film composition and processing conditions on the ordered structures. The structural characteristics of the meso-structures formed demonstrated to primarily rely on the lyotropic liquid crystal properties while the nature of the metal nano-particles used as well as the their diameters were found to affect the ordered structure formation. The impact of the annealing temperature on the nano-particle coalescence and efficiency at removing the templating lyotropic liquid crystals was also analysed. It is demonstrated that the lyotropic liquid crystal is rendered slightly less thermally stable, upon mixing with metal nano-particles and that low annealing temperatures are sufficient to form purely metallic frameworks with average pore size distributions smaller than 500 nm and porosity around 45% with potential application in sensing, catalysis, nanoscale heat exchange, and molecular separation.

  14. Antibacterial activity of carbon-coated zinc oxide particles.

    Sawai, Jun; Yamamoto, Osamu; Ozkal, Burak; Nakagawa, Zenbe-E

    2007-03-01

    Particles of ZnO coated with carbon (ZnOCC) were prepared and evaluated for their antibacterial activity. ZnO powder and poly(vinyl alcohol) (PVA) (polymerization degree: 2,000-95,000) were mixed at a mass ratio (ZnO/PVA) of 1, and then heated at 500-650 degree C for 3 h under argon gas with a flow rate of 50ml/min. Carbon deposited on the ZnOCC surface was amorphous as revealed by X-ray diffraction studies. The ZnOCC particles maintained their shape in water, even under agitation. The antibacterial activity of ZnOCC powder against Staphylococcus aureus was evaluated quantitatively by measuring the change in the electrical conductivity of the growth medium caused by bacterial metabolism (conductimetric assay). The conductivity curves obtained were analyzed using the growth inhibition kinetic model proposed by Takahashi for calorimetric evaluation, allowing the estimation of the antibacterial efficacy and kinetic parameters of ZnOCC. In a previous study, when ZnO was immobilized on materials, such as activated carbon, the amount of ZnO immobilized was approximately 10-50%, and the antibacterial activity markedly decreased compared to that of the original ZnO. On the other hand, the ZnOCC particles prepared in this study contained approximately 95% ZnO and possessed antibacterial activity similar to that of pure ZnO. The carbon-coating treatment could maintain the antibacterial efficacy of the ZnO and may be useful in the develop-ment of multifunctional antimicrobial materials. PMID:17408004

  15. Antioxidant activity of levan coated cerium oxide nanoparticles.

    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

  16. Effect of Porosity on Photocatalytic Activity of Plasma-Sprayed TiO2 Coating

    Zhang, Cheng; Chaudhary, Ujwal; Das, Santanu; Godavarty, Anuradha; Agarwal, Arvind

    2013-10-01

    The effect of porosity on photocatalytic activity of plasma-sprayed TiO2 coating on steel substrate is studied by varying processing parameters viz. plasma power and powder feed rate. The relationship between porosity content and methylene blue (MB) dye decomposition rate was established to correlate coating microstructure and its photocatalytic activity. The coating with the highest porosity content exhibited best photocatalytic efficiency. The same processing parameters were used to deposit TiO2 coating on FTO glass. The photocatalytic activity of TiO2 coating on FTO was 2.5 times better than TiO2 coating on the steel substrate. TiO2 coating on FTO glass contains bimodal porosity distribution (micropores and submicron pores) which accelerated MB decomposition by accelerated diffusion of ionic species.

  17. 纳米CdS:Cu双酶膜葡萄糖生物传感器%Study on CdS: Cu Nano-particles Dual-enzyme Membrane Glucose Biosensors

    李于善; 郭玲芝; 李菲菲; 徐丽

    2009-01-01

    将纳米CdS:Cu颗粒加入到葡萄糖酶(GOD)和辣根过氧化物酶(HRP)双酶膜中,与导电聚合物聚邻苯二胺(PoPD)经电化学聚合反应而固定此两酶,制备了电流型纳米CdS:Cu颗粒双酶膜葡萄糖生物传感器,分析了CdS:Cu纳米颗粒对传感器电流响应的影响,进行了传感器的性能测定.实验表明,引入CdS:Cu纳米粒子和PoPD后可显著改进传感器响应性能,线性范围为0.55~9.2 mmol/L,检测下限为0.55 mmol/L,响应时间为20 s.稳定工作215天,传感器活性指标无显著变化,且抗干扰性强.%CdS : Cu nano-particles were added to the glucose enzyme (GOD) and horseradish peroxidase (HRP) dual-enzyme membrane, and then reacted with conducting polymer poly o-phenylenediamine (PoPD) via electrochemical polymerization to fix these two enzymes and to prepare the current nano-CdS : Cu particle dual-enzyme membrane glucose biosensors. The response to electric current of CdS : Cu nano-particles in the biosensors was analyzed, and the performance of the biosensors was tested. The experimental results showed that the introduction of nano-particles and PoPD significantly enhanced the sensor response sensitivity. The linear range expanded to 0. 55 ~ 9. 2 mmol/L, and the detection limit reduced to 0. 55 mmol/L. The response time was 20 s. During 215 days, the biosensor worked steadily with no significant changes in activity and exhibited strong anti-interference property.

  18. Understanding the Adsorption Interface of Polyelectrolyte Coating on Redox Active Nanoparticles Using Soft Particle Electrokinetics and Its Biological Activity

    2015-01-01

    The application of cerium oxide nanoparticles (CNPs) for therapeutic purposes requires a stable dispersion of nanoparticles in a biological environment. The objective of this study is to tailor the properties of polyelectrolyte coated CNPs as a function of molecular weight to achieve a stable and catalytic active dispersion. The coating of CNPs with polyacrylic acid (PAA) has increased the dispersion stability of CNPs and enhanced the catalytic ability. The stability of PAA coating was analyzed using the change in the Gibbs free energy computed by the Langmuir adsorption model. The adsorption isotherms were determined using soft particle electrokinetics which overcomes the challenges presented by other techniques. The change in Gibbs free energy was highest for CNPs coated with PAA of 250 kg/mol indicating the most stable coating. The change in free energy for PAA of 100 kg/mol coated CNPs was 85% lower than the PAA of 250 kg/mol coated CNPs. This significant difference is caused by the strong adsorption of PAA of 100 kg/mol on CNPs. Catalytic activity of PAA-CNPs is assessed by the catalase enzymatic mimetic activity of nanoparticles. The catalase activity was higher for PAA coated CNPs as compared to bare CNPs which indicated preferential adsorption of hydrogen peroxide induced by coating. This indicates that the catalase activity is also affected by the structure of the coating layer. PMID:24673655

  19. Adsorption of doxorubicin on poly (methyl methacrylate) -chitosan-heparin coated activated carbon beads

    Miao, Jianjun; Zhang, Fuming; Takieddin, Majde; Mousa, Shaker; Linhardt, Robert J.

    2012-01-01

    Extracorporeal filter cartridges, filled with activated carbon bead (ACB) adsorbent, have been used for removal of overdosed cancer drugs from the blood. Coatings on adsorbent matrices, poly (methyl methacrylate) (PMMA)/activated carbon bead and PMMA/chitosan/heparin/ACB composites, were tested to improve their biocompatibility and blood compatibility. PMMA coating on ACBs was accomplished in a straightforward manner using a PMMA solution in ethyl acetate. One-step hybrid coating of ACBs with...

  20. Coat protein activation of alfalfa mosaic virus replication is concentration dependent.

    Guogas, Laura M; Laforest, Siana M; Gehrke, Lee

    2005-05-01

    Alfalfa mosaic virus (AMV) and ilarvirus RNAs are infectious only in the presence of the viral coat protein; therefore, an understanding of coat protein's function is important for defining viral replication mechanisms. Based on in vitro replication experiments, the conformational switch model states that AMV coat protein blocks minus-strand RNA synthesis (R. C. Olsthoorn, S. Mertens, F. T. Brederode, and J. F. Bol, EMBO J. 18:4856-4864, 1999), while another report states that coat protein present in an inoculum is required to permit minus-strand synthesis (L. Neeleman and J. F. Bol, Virology 254:324-333, 1999). Here, we report on experiments that address these contrasting results with a goal of defining coat protein's function in the earliest stages of AMV replication. To detect coat-protein-activated AMV RNA replication, we designed and characterized a subgenomic luciferase reporter construct. We demonstrate that activation of viral RNA replication by coat protein is concentration dependent; that is, replication was strongly stimulated at low coat protein concentrations but decreased progressively at higher concentrations. Genomic RNA3 mutations preventing coat protein mRNA translation or disrupting coat protein's RNA binding domain diminished replication. The data indicate that RNA binding and an ongoing supply of coat protein are required to initiate replication on progeny genomic RNA transcripts. The data do not support the conformational switch model's claim that coat protein inhibits the initial stages of viral RNA replication. Replication activation may correlate with low local coat protein concentrations and low coat protein occupancy on the multiple binding sites present in the 3' untranslated regions of the viral RNAs. PMID:15827190

  1. Genome activation by raspberry bushy dwarf virus coat protein.

    Macfarlane, Stuart A; McGavin, Wendy J

    2009-03-01

    Two sets of infectious cDNA clones of raspberry bushy dwarf virus (RBDV) have been constructed, enabling either the synthesis of infectious RNA transcripts or the delivery of infectious binary plasmid DNA by infiltration of Agrobacterium tumefaciens. In whole plants and in protoplasts, inoculation of RBDV RNA1 and RNA2 transcripts led to a low level of infection, which was greatly increased by the addition of RNA3, a subgenomic RNA coding for the RBDV coat protein (CP). Agroinfiltration of RNA1 and RNA2 constructs did not produce a detectable infection but, again, inclusion of a construct encoding the CP led to high levels of infection. Thus, RBDV replication is greatly stimulated by the presence of the CP, a mechanism that also operates with ilarviruses and alfalfa mosaic virus, where it is referred to as genome activation. Mutation to remove amino acids from the N terminus of the CP showed that the first 15 RBDV CP residues are not required for genome activation. Other experiments, in which overlapping regions at the CP N terminus were fused to the monomeric red fluorescent protein, showed that sequences downstream of the first 48 aa are not absolutely required for genome activation. PMID:19218221

  2. Bendable Electro-chemical Lactate Sensor Printed with Silver Nano-particles

    Abrar, Md Abu; Dong, Yue; Lee, Paul Kyuheon; Kim, Woo Soo

    2016-07-01

    Here we report a flexible amperometric lactate biosensor using silver nanoparticle based conductive electrode. Mechanically bendable cross-serpentine-shaped silver electrode is generated on flexible substrate for the mechanical durability such as bending. The biosensor is designed and fabricated by modifying silver electrode with lactate oxidase immobilized by bovine serum albumin. The in-sensor pseudo Ag/AgCl reference electrode is fabricated by chloridization of silver electrode, which evinced its long-term potential stability against a standard commercial Ag/AgCl reference electrode. The amperometric response of the sensor shows linear dependence with lactate concentration of 1~25 mM/L. Anionic selectivity is achieved by using drop-casted Nafion coated on silver electrode against anionic interferences such as ascorbate. This non-invasive electrochemical lactate sensor also demonstrates excellent resiliency against mechanical deformation and temperature fluctuation which leads the possibility of using it on human epidermis for continuous measurement of lactate from sweat. Near field communication based wireless data transmission is demonstrated to reflect a practical approach of the sensor to measure lactate concentration portably using human perspiration.

  3. Bendable Electro-chemical Lactate Sensor Printed with Silver Nano-particles

    Abrar, Md Abu; Dong, Yue; Lee, Paul Kyuheon; Kim, Woo Soo

    2016-01-01

    Here we report a flexible amperometric lactate biosensor using silver nanoparticle based conductive electrode. Mechanically bendable cross-serpentine-shaped silver electrode is generated on flexible substrate for the mechanical durability such as bending. The biosensor is designed and fabricated by modifying silver electrode with lactate oxidase immobilized by bovine serum albumin. The in-sensor pseudo Ag/AgCl reference electrode is fabricated by chloridization of silver electrode, which evinced its long-term potential stability against a standard commercial Ag/AgCl reference electrode. The amperometric response of the sensor shows linear dependence with lactate concentration of 1~25 mM/L. Anionic selectivity is achieved by using drop-casted Nafion coated on silver electrode against anionic interferences such as ascorbate. This non-invasive electrochemical lactate sensor also demonstrates excellent resiliency against mechanical deformation and temperature fluctuation which leads the possibility of using it on human epidermis for continuous measurement of lactate from sweat. Near field communication based wireless data transmission is demonstrated to reflect a practical approach of the sensor to measure lactate concentration portably using human perspiration. PMID:27465437

  4. Evolution of structural properties of iron oxide nano particles during temperature treatment from 250{\\deg}C - 900{\\deg}C: X-ray diffraction and Fe K-shell pre-edge X-ray absorption study

    Bora, Debajeet K.; Braun, Artur; Erat, Selma; Safonova, Olga; Graule, Thomas; Constable, Edwin C.

    2011-01-01

    Iron oxide nano particles with nominal Fe2O3 stoichiometry were synthesized by a wet, soft chemical method with the heat treatment temperatures from 250{\\deg}C to 900{\\deg}C in air. The variation in the structural properties of the nano particles with the heat treatment temperature was studied by X-ray diffraction and Fe K shell X-ray absorption study. X-ray diffractograms show that at lower annealing temperatures nano particle comprises both maghemite and hematite phases. With increasing tem...

  5. Dispensing of high concentration Ag nano-particles ink for ultra-low resistivity paper-based writing electronics

    Wang, Fuliang; Mao, Peng; He, Hu

    2016-02-01

    Paper-based writing electronics has received a lot of interest recently due to its potential applications in flexible electronics. To obtain ultra-low resistivity paper-based writing electronics, we developed a kind of ink with high concentration of Ag Nano-particles (up to 80 wt%), as well as a related dispensing writing system consisting an air compressor machine and a dispenser. Additionally, we also demonstrated the writability and practical application of our proposed ink and writing system. Based on the study on the effect of sintering time and pressure, we found the optimal sintering time and pressure to obtain high quality Ag NPs wires. The electrical conductivity of nano-silver paper-based electronics has been tested using the calculated resistivity. After hot-pressure sintering at 120 °C, 25 MPa pressure for 20 minutes, the resistivity of silver NPs conductive tracks was 3.92 × 10-8 (Ωm), only 2.45 times of bulk silver. The mechanical flexibility of nano-silver paper-based electronics also has been tested. After 1000 bending cycles, the resistivity slightly increased from the initial 4.01 × 10-8 to 5.08 × 10-8 (Ωm). With this proposed ink preparation and writing system, a kind of paper-based writing electronics with ultra-low resistivity and good mechanical flexibility was achieved.

  6. White top-emitting organic light-emitting diodes with solution-processed nano-particle scattering layers

    Schaefer, Tim [Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden (Germany); Institut für Physikalische Chemie, Universität zu Köln, 50939 Köln (Germany); Schwab, Tobias; Lenk, Simone [Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden (Germany); Gather, Malte C., E-mail: mcg6@st-andrews.ac.uk [Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden (Germany); Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, Scotland (United Kingdom)

    2015-12-07

    A random scattering approach to enhance light extraction in white top-emitting organic light-emitting diodes (OLEDs) is reported. Through solution processing from fluorinated solvents, a nano-particle scattering layer (NPSL) can be deposited directly on top of small molecule OLEDs without affecting their electrical performance. The scattering length for light inside the NPSL is determined from transmission measurements and found to be in agreement with Mie scattering theory. Furthermore, the dependence of the light outcoupling enhancement on electron transport layer thickness is studied. Depending on the electron transport layer thickness, the NPSL enhances the external quantum efficiency of the investigated white OLEDs by between 1.5 and 2.3-fold. For a device structure that has been optimized prior to application of the NPSL, the maximum external quantum efficiency is improved from 4.7% to 7.4% (1.6-fold improvement). In addition, the scattering layer strongly reduces the undesired shift in emission color with viewing angle.

  7. Nucleation and dissociation of nano-particles in gas phase; Nucleation et evaporation de nanoparticules en phase gazeuse

    Feiden, P

    2007-09-15

    This work deals with the study of nano-particles formation in gas phase and their dissociation pathways after an optical excitation. The clusters formation decomposes in two steps: a seed is formed (nucleation phase) and sticks atoms during its propagation in a sodium atomic vapor (growth phase). Those two steps have been observed separately for homogeneous Na{sub n} and heterogeneous Na{sub n}X particles (X = (NaOH){sub 2} or (Na{sub 2}O){sub 2}). The growth mechanism is well interpreted by a Monte Carlo simulation taking into account an accretion mechanism with hard-sphere cross section. The homogeneous nucleation mechanism has been highlighted by a direct comparison with the Classical Nucleation Theory predictions. The clusters fragmentation of ionic Na{sup +}(NaOH){sub p} et Na{sup +}(NaF){sub p} particles is studied in the second part. The way clusters fragment with size when they are excited optically is compared with theoretical previsions: this highlights the existence of an energetic barrier for special size of clusters. Finally, the fragmentation of doubly charged Na{sup +} Na{sup +} (NaOH){sub p} clusters shows a competition between the fission into two single charged fragments and the unimolecular evaporation of a neutral fragment. (author)

  8. 3-dimensional free standing micro-structures by proton beam writing of Su 8-silver nanoParticle polymeric composite

    Proton beam lithography a maskless direct-write lithographic technique (well suited for producing 3-Dimensional microstructures in a range of resist and semiconductor materials) is demonstrated as an effective tool in the creation of electrically conductive freestanding micro-structures in an Su 8 + Nano Silver polymer composite. The structures produced show non-ohmic conductivity and fit the percolation theory conduction model of tunneling of separated nanoparticles. Measurements show threshold switching and a change in conductivity of at least 4 orders of magnitude. The predictable range of protons in materials at a given energy is exploited in the creation of high aspect ratio, free standing micro-structures, made from a commercially available SU8 Silver nano-composite (GMC3060 form Gersteltec Inc. a negative tone photo-epoxy with added metallic nano-particles(Silver)) to create films with enhanced electrical properties when exposed and cured. Nano-composite films are directly written on with a finely focused MeV accelerated Proton particle beam. The energy loss of the incident proton beams in the target polymer nano- composite film is concentrated at the end of its range, where damage occurs; changing the chemistry of the nano-composite film via an acid initiated polymerization - creating conduction paths. Changing the energy of the incident beams provide exposed regions with different penetration and damage depth - exploited in the demonstrated cantilever microstructure.

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

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

    2015-10-01

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

  10. Intracranial stents past, present and the future trend: stents made with nano-particle or nanocomposite biomaterials.

    Zhao, Junjie; Kalaskar, Deepak; Farhatnia, Yasmin; Bai, Xiaoxin; Bulter, Peter E; Seifalian, Alexander M

    2014-01-01

    Stroke or cerebral vascular accidents are among the leading causes of death in the world. With the availability of Digital Subtraction Angiography, transluminal angioplasty has become feasible in many situations and the role of intracranial stents is becoming ever more important in the management of cerebral vascular diseases. In current review, we outline the chronological development of various stents namely; balloon expandable stent, self-expandable open cell stent, self-expandable close cell stent and the flow diverting stent. Further we discuss their advantages and limitations in terms of stent migration, thromboemboli, damage to vessels during procedure, in-stent stenosis and hyper-perfusion damage. We also discuss the importance of in-situ endothelialization, controlled expandability and hemodynamic manipulation in stent design. Further, we summarized the role and need for further development in the areas of bio-compatible materials, endothelial progenitor cell capture technique, bio-functionalized-magnetic-nano-particles and nanotechnology which are significant in intracranial stent development. PMID:25039772

  11. Growth of copper nano particles in erio nite matrix;Crecimiento de nanoparticulas de cobre en matriz de erionita

    Chavez R, F.; Zamorano U, R. [Instituto Politecnico Nacional, Escuela Superior de Fisica y Matematicas, Departamento de Fisica, Unidad Profesional Adolfo Lopez Mateos, Zacatenco, 07738 Mexico D. F. (Mexico); Petranovskii, V., E-mail: fchavez@esfm.ipn.m [UNAM, Centro de Nanociencias y Nanotecnologia, Apdo. Postal 14, 22800 Ensenada, Baja California (Mexico)

    2010-07-01

    Unreduced and reduced in hydrogen flow copper exchanged synthetic erio nite, with a SiO{sub 2}/Al{sub 2}O{sub 3} molar ratio of 7.7, have been characterized by X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, and electron spin resonance spectroscopy. The X-ray diffraction patterns show that the reduction process does not change the zeolite structure, besides the reduced form at 450 grades C present diffraction lines assigned to copper metallic particles. The diffuse reflectance spectroscopy measurements have detected isolated Cu{sup 2+} ions as well as plasma resonance peak of copper metallic nanoparticles. The spin resonance spectroscopy simulation analysis of the spectra measured at 20 grades C indicates the presence of two different Cu{sup 2+} ions sites localized in the erio nite matrix. Up to 450 grades C only one type of sites take place in the reduction process, participating in Cu metal clusters and Cu metal nano particles formation, keeping the Cu{sup 2+} ions of the second site intact. (Author)

  12. Influence of Ingredients of Carbon Black Nano-Particle Suspension of Ammonia Solution on Viscosity of Nanofluid

    CHENG Bo; DU Kai; ZHANG Xiao-song; YANG Liu

    2009-01-01

    A series of experiments were performed on the viscosity of a nanofluid,produced by mixing car-bon black and mulsifier OP-10 using ammonia-water with the ultrasonic dispersion.The results show that,when adding surfactant separately in low mass concentrations,at first the viscosity of solution decreases sharply compared with that of ammonia-water.then increases with increasing the concentration of OP-IO.In a certain concentration of surfactant,the viscosity of nanofluids increases with increasing the concentration of nanoparti·des.Based on Einstein model and Langrnuir absorption theory,a new model啪s summed up for nanoflukls.Compared with test values,the calcuhted values on the new model have verified that the model is suitable to predict the viscosity of rmnofluids.beoll.k.the maximum relative error is less than 5%.Nano-particles absorp-tion in the nanofluids is not only single-molecule layer adsorption,but aLso multi-layer molecular adsorption and other complicated adsorption.So the new model,ordy based on single-molecule layer adsorption theory of Lang-muir.is not fully in line with the real circumstances.

  13. Calcium phosphate coating containing silver shows high antibacterial activity and low cytotoxicity and inhibits bacterial adhesion

    Ando, Yoshiki, E-mail: andoy@jmmc.jp [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Research Department, Japan Medical Materials Corporation, Uemura Nissei Bldg.9F 3-3-31 Miyahara, Yodogawa-ku, Osaka 532-0003 (Japan); Miyamoto, Hiroshi [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Noda, Iwao; Sakurai, Nobuko [Research Department, Japan Medical Materials Corporation, Uemura Nissei Bldg.9F 3-3-31 Miyahara, Yodogawa-ku, Osaka 532-0003 (Japan); Akiyama, Tomonori [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Yonekura, Yutaka; Shimazaki, Takafumi; Miyazaki, Masaki; Mawatari, Masaaki; Hotokebuchi, Takao [Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan)

    2010-01-01

    Surgical site infection is one of the serious complications of orthopedic implants. In order to reduce the incidence of implant-associated infections, we developed a novel coating technology of calcium phosphate (CP) containing silver (Ag), designated Ag-CP coating, using a thermal spraying technique. In this study, we evaluated the antibacterial efficacy and biological safety of this coating. In vitro antibacterial activity tests showed that the growths of Escherichia coli, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) are completely suppressed on Ag-CP coating. In vitro bacterial adherence tests revealed that the number of adherent bacteria on the surface of this coating is significantly less (p < 0.02) than that on the surface of the CP coating. Moreover, the Ag-CP coating completely inhibits MRSA adhesion [<10 colony-forming units (CFU)] when 10{sup 2} CFU MRSA is inoculated. On the other hand, V79 Chinese hamster lung cells were found to grow on the Ag-CP coating as well as on the CP coating in a cytotoxicity test. These results indicate that the Ag-CP coating on the surface of orthopedic implants exhibits antibacterial activity and inhibits bacterial adhesion without cytotoxicity.

  14. Growth of Carbon Nanotubes over Ni Nano-particles Prepared in Situ by Reduction of La2NiO4 Oxides

    2000-01-01

    A novel catalyst precursor, La2NiO4, was investigated to synthesize carbon nanotubes, obtained from catalytic disproportionation of CO. The morphology of carbon nanotubes has been examined by TEM (transmission electron micrograph) and SEM (scaning electron micrograph). It was observed that the Ni nano-particle size formed at different reducing temperatures was a key factor to the yield and diameter of carbon nanotubes.

  15. Corrosion Characteristics of Nano-structured Coatings for the Application in Secondary Piping System of Nuclear Power Plants

    Coating surface using less corrosive metal is one of methods that reduce electrochemical corrosion. And metal oxide like a TiO2 is studied because it is stable, insoluble when coating is exposed severe environment. Several coating technics are used for better corrosion resistance. Pysical vapor deposition(PVD), chemical vapor deposition(CVD), thermal spray, electroplating, electroless etc. But thermal spray coating makes thermal stress to substrates because its temperature are more than 3000K. And powder's deformation can occur. And CVD makes decarburization near interface between surface and coating layer. In addition, CVD and PVD needs vacuum chamber. Electroplating is chemical reaction at surface, but it needs electric power. On the other hands, electroless plating dosen't needs electric power and it's temperature is low than thermal spray. Also the pipe dipping into the chemically solution can proceed coating easily. To reduce FAC, we have experiment about corrosion resistance of electroless Ni-P coated carbon steel in room temperature. And it has possibility of reducing corrosion and addition of TiO2 nano particles in Ni-P coating layer makes having better corrosion resistance. And results give us a possibility that electroless Ni-P coating added TiO2 nano particle can have better corrosion resistance compared carbon steel. So it needs study about high temperature corrosion experiment of electroless Ni-P coating added TiO2 nano particle

  16. Corrosion Characteristics of Nano-structured Coatings for the Application in Secondary Piping System of Nuclear Power Plants

    Kim, Jeong Won; Kim, Seung Hyun; Kim, Ji Hyun [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2015-05-15

    Coating surface using less corrosive metal is one of methods that reduce electrochemical corrosion. And metal oxide like a TiO{sub 2} is studied because it is stable, insoluble when coating is exposed severe environment. Several coating technics are used for better corrosion resistance. Pysical vapor deposition(PVD), chemical vapor deposition(CVD), thermal spray, electroplating, electroless etc. But thermal spray coating makes thermal stress to substrates because its temperature are more than 3000K. And powder's deformation can occur. And CVD makes decarburization near interface between surface and coating layer. In addition, CVD and PVD needs vacuum chamber. Electroplating is chemical reaction at surface, but it needs electric power. On the other hands, electroless plating dosen't needs electric power and it's temperature is low than thermal spray. Also the pipe dipping into the chemically solution can proceed coating easily. To reduce FAC, we have experiment about corrosion resistance of electroless Ni-P coated carbon steel in room temperature. And it has possibility of reducing corrosion and addition of TiO{sub 2} nano particles in Ni-P coating layer makes having better corrosion resistance. And results give us a possibility that electroless Ni-P coating added TiO{sub 2} nano particle can have better corrosion resistance compared carbon steel. So it needs study about high temperature corrosion experiment of electroless Ni-P coating added TiO{sub 2} nano particle.

  17. Effect of zinc-containing β-tricalcium phosphate nano particles injection on jawbone mineral density and mechanical strength of osteoporosis model rats

    Zinc-containing β-tricalcium phosphate (ZnTCP) nano particles were injected into zinc-deficient rats to promote osteogenesis. Sprague-Dawley (SD) rats (4 weeks old, average weight of 70 g) were divided into four groups: Normal rats (not ovariectomized (OVX)), Control rats (OVX), and OVX rats injected with a suspension of ZnTCP nano particles or ZnSO4. The ZnTCP contained 6.17% zinc. The suspensions (0.6 mg as a zinc volume/0.2 ml) were injected around the jaw bone once a week for 12 weeks. Local effects on the bone mineral content (BMC) of jawbone, and systemic effects on body weight, the BMC of both femurs determined by X-ray computed tomography, and bone mechanical strength (BMS) measured by the three-point bending method, were examined. The BMC of jaw bone was significantly higher in the ZnTCP-treated group than un-treated or ZnSO4-treated group. Body weight, the BMC of femurs, and BMS were also significantly higher in the ZnTCP treated-group. The zinc-containing β-tricalcium phosphate nano particles were effective at preventing bone loss induced by ovariectomy in rats and have potential uses for treating periodontitis. (author)

  18. A survey of strippable and tie-down coatings for use in the decommissioning of alpha-active facilities

    The paper concerns temporary coatings for use in decommissioning operations of alpha-active facilities. The various temporary coating options are described with respect to: decontamination by removal of a previously applied protective coating, and the in-situ application of a coating for tie-down or decontamination duties. The specifications for coating systems to be used in active areas are defined in general terms. A survey of currently available temporary coating material is given, as well as the suitability of commercially available coating systems. (U.K.)

  19. Photocatalytic Degradation of Methylene Blue using ZnO Nano-Particles

    A. Rezaee; H Masombaigi; A Nasiri

    2009-01-01

    "nBackgrounds and Objectives: Textile industrial wastewaters are one of the important sources of environmental contaminants. In the recent years, use of advanced oxidation processes, by producing highly active and reactive components such as hydroxyl radicals has been proposed. The aim of this research is photocatalytic degradation of methylene blue dye using the ZnO-nanoparticle with UVA irradiation. "nMaterials and Methods: photocatalytic degradation of methylene blue color using the ZnO- n...

  20. Internal Porosity of Mineral Coating Supports Microbial Activity in Rapid Sand Filters for Groundwater Treatment

    Gülay, Arda; Tatari, Karolina; Musovic, Sanin;

    2014-01-01

    A mineral coating develops on the filter grain surface when groundwater is treated via rapid sand filtration in drinking water production. The coating changes the physical and chemical properties of the filter material, but little is known about its effect on the activity, colonization, diversity...

  1. Electrodeposition, characterization, and antibacterial activity of zinc/silver particle composite coatings

    Highlights: • Zn/AgPs composites coatings were formed for electrodeposition. • CTAB promotes occlusion of silver particles in the coating. • Zn/AgPs coatings present very good antibacterial activity. - Abstract: Composite coatings consisting of zinc and silver particles (Zn/AgPs) with antibacterial activity were prepared using an electrodeposition technique. The morphology, composition, and structure of the Zn/AgPs composite coatings were analyzed using scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), inductively coupled plasma (ICP) spectrometry, and X-ray diffraction (XRD). The antibacterial properties of the coatings against the microorganisms Escherichia coli as a model Gram-negative bacterium and Staphylococcus aureus as a model Gram-positive bacterium were studied quantitatively and qualitatively. The results revealed that the dispersant cetyltrimethylammonium bromide (CTAB) assisted in the formation of a stable suspension of Ag particles in the electrolytic bath for 24 h. Likewise, a high concentration of CTAB in the electrolytic bath promoted an increase in the number of Ag particles occluded in the Zn/AgPs coatings. The Zn/AgPs coatings that were obtained were compact, smooth, and shiny materials. Antimicrobial tests performed on the Zn/AgPs coatings revealed that the inhibition of bacterial growth after 30 min of contact time was between 91% and 98% when the AgPs content ranged from 4.3 to 14.0 mg cm−3

  2. Electrodeposition, characterization, and antibacterial activity of zinc/silver particle composite coatings

    Reyes-Vidal, Y.; Suarez-Rojas, R.; Ruiz, C.; Torres, J. [Center of Research and Technological Development in Electrochemistry (CIDETEQ), Parque Tecnológico Sanfandila, Pedro Escobedo, Querétaro, A.P.064, C.P.76703, Querétaro (Mexico); Ţălu, Ştefan [Technical University of Cluj-Napoca, Faculty of Mechanical Engineering, Department of AET, Discipline of Descriptive Geometry and Engineering Graphics, 103-105 B-dul Muncii St., Cluj-Napoca 400641 Cluj (Romania); Méndez, Alia [Centro de Química-ICUAP Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria Puebla, 72530 Puebla (Mexico); Trejo, G., E-mail: gtrejo@cideteq.mx [Center of Research and Technological Development in Electrochemistry (CIDETEQ), Parque Tecnológico Sanfandila, Pedro Escobedo, Querétaro, A.P.064, C.P.76703, Querétaro (Mexico)

    2015-07-01

    Highlights: • Zn/AgPs composites coatings were formed for electrodeposition. • CTAB promotes occlusion of silver particles in the coating. • Zn/AgPs coatings present very good antibacterial activity. - Abstract: Composite coatings consisting of zinc and silver particles (Zn/AgPs) with antibacterial activity were prepared using an electrodeposition technique. The morphology, composition, and structure of the Zn/AgPs composite coatings were analyzed using scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), inductively coupled plasma (ICP) spectrometry, and X-ray diffraction (XRD). The antibacterial properties of the coatings against the microorganisms Escherichia coli as a model Gram-negative bacterium and Staphylococcus aureus as a model Gram-positive bacterium were studied quantitatively and qualitatively. The results revealed that the dispersant cetyltrimethylammonium bromide (CTAB) assisted in the formation of a stable suspension of Ag particles in the electrolytic bath for 24 h. Likewise, a high concentration of CTAB in the electrolytic bath promoted an increase in the number of Ag particles occluded in the Zn/AgPs coatings. The Zn/AgPs coatings that were obtained were compact, smooth, and shiny materials. Antimicrobial tests performed on the Zn/AgPs coatings revealed that the inhibition of bacterial growth after 30 min of contact time was between 91% and 98% when the AgPs content ranged from 4.3 to 14.0 mg cm{sup −3}.

  3. Adsorption of doxorubicin on poly(methyl methacrylate)-chitosan-heparin-coated activated carbon beads.

    Miao, Jianjun; Zhang, Fuming; Takieddin, Majde; Mousa, Shaker; Linhardt, Robert J

    2012-03-01

    Extracorporeal filter cartridges, filled with an activated carbon bead (ACB) adsorbent, have been used for removal of overdosed cancer drugs from the blood. Coatings on adsorbent matrices, poly(methyl methacrylate) (PMMA)/activated carbon bead and PMMA/chitosan/heparin/ACB composites, were tested to improve their biocompatibility and blood compatibility. PMMA coating on ACBs was accomplished in a straightforward manner using a PMMA solution in ethyl acetate. A one-step hybrid coating of ACBs with PMMA-anticoagulant heparin required the use of acetone and water co-solvents. Multilayer coatings with three components, PMMA, chitosan, and heparin, involved three steps: PMMA was first coated on ACBs; chitosan was then coated on the PMMA-coated surface; and finally, heparin was covalently attached to the chitosan coating. Surface morphologies were studied by scanning electron microscopy. X-ray photoelectron spectroscopy confirmed the -SO(3)(-) group. Adsorption, of a chemotherapy drug (doxorubicin) from both water and phosphate-buffered saline, by the coated ACBs was examined. The adsorption isotherm curves were fitted using the Freundlich model. The current adsorption system might find potential applications in the removal of high-dose regional chemotherapy drugs while maintaining high efficiency, biocompatibility, and blood compatibility. PMID:22313019

  4. Hexa- and Dodeca-nuclear Poly-oxo-molybdate Cyclic Compounds: Application toward the Facile Synthesis of Nano-particles and Film Electrodeposition

    Two new compounds based on O3PCH2PO34- ligands and (Mo(V)2O4) dimeric units have been synthesized and structurally characterized. The dodeca-nuclear Mo(V) poly-oxo-molybdate species in (NH4)18[(Mo(V)2O4)6(OH)6(O3PCH2PO3)6)].33 H2O (1) is a cyclohexane-like ring in a chair conformation with pseudo S, symmetry. In the solid state, the wheels align side by side, thus delimiting large rectangular voids. The hexa-nuclear anion in Na8[(Mo(V)2O4)3(O3PCH2PO3)3(CH3AsO3)].19H2O (2) has a triangular framework and encapsulates a methylarsenato ligand. 31P NMR spectroscopic analysis revealed the stability of 2 in various aqueous media, whereas the stability of 1 depends on the nature of the cations present in solution. It has been evidenced that the transformation of 1 into 2 occurs in the presence of CH3AsO32- ions. This behavior shows that 1 call be used as a new precursor for the synthesis of Mo(V)/diphosphonate systems. The two complexes were very efficient both as reductants of Pt and Pd metallic salts and as capping agents for the resulting Pt0 and Pd0 nano-particles. The size of the obtained nano-particles depends both on the nature of the poly-oxo-metalate (POM i.e., 1 or 2) and on the [metallic salt]/[POM] ratio. In all cases, X-ray photoelectron spectroscopy (XPS) measurements have revealed the presence of Mo(VI) species that stabilize the nano-particles and the absence of Mo(V) moieties. Diffuse-reflectance FTIR spectra of the Pt nano-particles show that the capping Mo(VI) POMs are identical for both systems and contain the di-phosphonato ligand. The colloidal solutions do not show any precipitate and the nano-particles remain well-dispersed for several months. The electrochemical reduction of Mo(V) species was studied for 2. Cyclic voltammetry alone and electrochemical quartz crystal microbalance coupled with cyclic voltammetry show the deposition of a film on the electrode surface during this reduction. (authors)

  5. 硬脂酸改性纳米ZnO的研究%Modification of ZnO Nano-particles with Stearic Acid

    周莉; 魏珂瑶; 张建中; 吴海艳

    2012-01-01

    采用酯化反应法,以水为溶剂,采用硬脂酸对纳米ZnO的表面进行改性,对改性效果进行测试表征.其最佳工艺条件为:硬脂酸质量分数为6%,反应温度为90℃,反应时间为90 min.结果表明,改性后的ZnO粒子呈纳米级的分散,亲油化度值达到72.31%,吸水率达到3.04%;经表面改性的纳米ZnO表现了很好的亲油疏水性;改性后的纳米ZnO表面引入了硬脂酸的官能团,使其表面羟基的数目明显减少,其改性机理为纳米ZnO表面羟基与硬脂酸分子中的羧基发生了类似醇和酸的酯化反应.%Using the distilled water as solvent, stearic acid was used to modify the surface of ZnO nano-particles by esterification method. The effect of modification was measured and characterized. The optimum conditions were that the mass fraction of stearic acid, reaction temperature and reaction time were 6%, 90 °C, 90 min, respectively. The results show that the modified ZnO nano-particles are dispersed in nano-level and the lipophilic value and water absorption are 72.31% and 3.04% respectively. The modified ZnO nano-particles have well lipophilic. IR spectra shows that the functional groups of stearic acid are introduced to the surfaces of modified ZnO nano-particles, and the number of hydroxyl groups on the surfaces is significantly reduced. The modification mechanism is that the hydroxyl groups on the surfaces of ZnO nano-particles react with the carboxyl groups of stearic acid by esterification.

  6. Particle size dependent magnetic properties and phase transitions in multiferroic BiFeO{sub 3} nano-particles

    Annapu Reddy, V., E-mail: reddydph@iitr.ernet.in [Ferroelectric Materials and Devices Research Laboratory, Department of Physics, Indian Institute of Technology Roorkee, Uttarakhand 247667 (India); Radio Frequency Integrated Circuits Research Laboratory, Department of Electronics and Computer Engineering, Indian Institute of Technology Roorkee, Uttarakhand 247667 (India); Pathak, N.P. [Radio Frequency Integrated Circuits Research Laboratory, Department of Electronics and Computer Engineering, Indian Institute of Technology Roorkee, Uttarakhand 247667 (India); Nath, R., E-mail: rnathfph@iitr.ernet.in [Ferroelectric Materials and Devices Research Laboratory, Department of Physics, Indian Institute of Technology Roorkee, Uttarakhand 247667 (India)

    2012-12-05

    Highlights: Black-Right-Pointing-Pointer Nano-particles of Bismuth ferrite was synthesized by spray pyrolysis technique at low temperature. Black-Right-Pointing-Pointer Bismuth ferrite exhibits room temperature weak ferromagnetism. Black-Right-Pointing-Pointer The adsorbate induced spin polarization screening in Bismuth ferrite nanoparticles. Black-Right-Pointing-Pointer The superparaelectric size of Bismuth ferrite was determined. Black-Right-Pointing-Pointer The phase transitions shift with particle size are discussed base on the modified Ising model. - Abstract: The particle size effect in the range 10-150 nm on the magnetic properties and phase transitions in BiFeO{sub 3} samples prepared by spray pyrolysis method has been studied. The phase purity and structure have been investigated by XRD and FTIR spectroscopy analysis. The FTIR peaks of the nanoparticles shift to lower wave number due to increase surface area and grain boundaries. The Fe-SEM and TEM images show that the particles are uniform, dense and of nearly spherical shape nanoparticles. The significant enhancement in magnetization with finite coercive field has been observed in 12 nm particle size samples. The increase in magnetization is about four times larger than that of the bulk samples. It has been attributed to the suppression of the cycloidal spin structure due to large uncompensated spins of Fe{sup +3} ions at the surface of the particle and the adsorbate induced spin polarization screening in BFO nanoparticles. The phase transitions above room temperature have been investigated by DTA measurements and show that Neel temperature (T{sub N}) and Curie temperature (T{sub c}) increase with particle size. The shift in T{sub N} and T{sub c} values with particle size are fitted well to the finite scaling models. The microscopic parameters like correction length, characteristic microscopic dimension of the system and critical particle size have been evaluated which provide more physical insight in

  7. Particle size dependent magnetic properties and phase transitions in multiferroic BiFeO3 nano-particles

    Highlights: ► Nano-particles of Bismuth ferrite was synthesized by spray pyrolysis technique at low temperature. ► Bismuth ferrite exhibits room temperature weak ferromagnetism. ► The adsorbate induced spin polarization screening in Bismuth ferrite nanoparticles. ► The superparaelectric size of Bismuth ferrite was determined. ► The phase transitions shift with particle size are discussed base on the modified Ising model. - Abstract: The particle size effect in the range 10–150 nm on the magnetic properties and phase transitions in BiFeO3 samples prepared by spray pyrolysis method has been studied. The phase purity and structure have been investigated by XRD and FTIR spectroscopy analysis. The FTIR peaks of the nanoparticles shift to lower wave number due to increase surface area and grain boundaries. The Fe-SEM and TEM images show that the particles are uniform, dense and of nearly spherical shape nanoparticles. The significant enhancement in magnetization with finite coercive field has been observed in 12 nm particle size samples. The increase in magnetization is about four times larger than that of the bulk samples. It has been attributed to the suppression of the cycloidal spin structure due to large uncompensated spins of Fe+3 ions at the surface of the particle and the adsorbate induced spin polarization screening in BFO nanoparticles. The phase transitions above room temperature have been investigated by DTA measurements and show that Néel temperature (TN) and Curie temperature (Tc) increase with particle size. The shift in TN and Tc values with particle size are fitted well to the finite scaling models. The microscopic parameters like correction length, characteristic microscopic dimension of the system and critical particle size have been evaluated which provide more physical insight in the finite scaling effect in the nanoparticle samples.

  8. Micro/nano-particle decorated metal wire for cutting soft matter

    Zhang, Wei; Feng, Liang-liang; Wu, Fan; Zhang, Run-run; Wu, Cheng-wei

    2016-09-01

    To cut soft materials such as biological tissues with minimal damage and reduced positional error is highly desired in medical surgery and biomechanics. After years of natural selection and evolution, mosquitoes have acquired the ability to insert their proboscises into human skin with astonishingly tiny forces. This can be associated with the unique structure of their proboscises, with micro/nano sawteeth, and the distinctive insertion manner: high frequency reciprocating saw cutting. Inspired by these, this communication describes the successful implantation of metal oxide particles onto molybdenum wire surfaces through a sol-calcination process, to form a biomimetic sawblade with a high density of micro/nano saw teeth, where the acidification is essential in terms of generating active anchoring sites on the wire. When used as a sawblade in conjunction with reciprocating action to cut the viscoelastic gel, both the cut-in force and cut-in displacement could be decreased substantially. The cutting speed and frequency of reciprocating action are important operating parameters influencing cut-in force.

  9. Micro/nano-particle decorated metal wire for cutting soft matter.

    Zhang, Wei; Feng, Liang-Liang; Wu, Fan; Zhang, Run-Run; Wu, Cheng-Wei

    2016-09-01

    To cut soft materials such as biological tissues with minimal damage and reduced positional error is highly desired in medical surgery and biomechanics. After years of natural selection and evolution, mosquitoes have acquired the ability to insert their proboscises into human skin with astonishingly tiny forces. This can be associated with the unique structure of their proboscises, with micro/nano sawteeth, and the distinctive insertion manner: high frequency reciprocating saw cutting. Inspired by these, this communication describes the successful implantation of metal oxide particles onto molybdenum wire surfaces through a sol-calcination process, to form a biomimetic sawblade with a high density of micro/nano saw teeth, where the acidification is essential in terms of generating active anchoring sites on the wire. When used as a sawblade in conjunction with reciprocating action to cut the viscoelastic gel, both the cut-in force and cut-in displacement could be decreased substantially. The cutting speed and frequency of reciprocating action are important operating parameters influencing cut-in force. PMID:27456430

  10. NOVEL PREPARATION AND MAGNETO CHEMICAL CHARACTERIZATION OF NANO-PARTICLE MIXED ALCOHOL CATALYSTS

    Seetala V. Naidu; Upali Siriwardane

    2005-01-14

    We have developed effective nanoparticle incorporated heterogeneous F-T catalysts starting with the synthesis of Fe, Co, Cu nanoparticles using Fe(acac){sub 3}, Co(acac){sub 2}, and Cu(acac){sub 2} precursors and incorporating the nanoparticles into alumina sol-gel to yield higher alkanes production. SEM/EDX, XRD, BET, VSM and SQUID experimental techniques were used to characterize the catalysts, and GC/MS were used for catalytic product analysis. The nanoparticle oxide method gave the highest metal loading. In case of mixed metals it seems that Co or Cu interferes and reduces Fe metal loading. The XRD pattern for nanoparticle mixed metal oxides show alloy formation between cobalt and iron, and between copper and iron in sol-gel prepared alumina granules. The alloy formation is also supported by DTA and VMS data. The magnetization studies were used to estimate the catalyst activity in pre- and post-catalysts. A lower limit of {approx}40% for the reduction efficiency was obtained due to hydrogenation at 450 C for 4 hrs. About 85% of the catalyst has become inactive after 25 hrs of catalytic reaction, probably by forming carbides of Fe and Co. The low temperature (300 K to 4.2 K) SQUID magnetometer results indicate a superparamagnetic character of metal nanoparticles with a wide size distribution of < 20 nm nanoparticles. We have developed an efficient and economical procedure for analyzing the F-T products using low cost GC-TCD system with hydrogen as a carrier gas. Two GC columns DC 200/500 and Supelco Carboxen-1000 column were tested for the separation of higher alkanes and the non-condensable gases. The Co/Fe on alumina sol-gel catalyst showed the highest yield for methane among Fe, Co, Cu, Co/Fe, Cu/Co, Fe/Cu. The optimization of CO/H{sub 2} ratio indicated that 1:1 ratio gave more alkanes distribution in F-T process with Co/Fe (6% each) impregnated on alumina mesoporous catalyst.

  11. Enhanced Photoelectrochemical Activity of ZnO-Coated TiO2 Nanotubes and Its Dependence on ZnO Coating Thickness.

    Cai, Hua; Liang, Peipei; Hu, Zhigao; Shi, Liqun; Yang, Xu; Sun, Jian; Xu, Ning; Wu, Jiada

    2016-12-01

    One-dimensional heterogeneous nanostructures in the form of ZnO-coated TiO2 nanotubes (ZnO/TiO2 NTs) were fabricated by atomic layer deposition of an ultrathin ZnO coating on electrochemical anodization-formed TiO2 nanotubes (NTs) with the thickness of ZnO coating being precisely controlled at atomic scale, and the photoelectrochemical activity of the fabricated ZnO/TiO2 NTs and the influence of ZnO coating and its thickness were studied. The structures of TiO2 NTs and ZnO coatings were characterized by X-ray diffraction, Raman backscattering spectroscopy, and transmission electron microscopy. The photoelectrochemical activity was studied through the measurements of electrochemical impendence, flat-band potential, and transient photocurrent density. The TiO2 NTs exhibit anatase structure, and the ZnO coatings are structured with hexagonal wurtzite. The photoelectrochemical activity of the ZnO/TiO2 NTs is strongly dependent on the thickness of ZnO coating. ZnO/TiO2 NTs with a thinner rather than a thicker ZnO coating exhibit better photoelectrochemical activity with reduced charge transfer resistance, increased negative flat-band potentials, and enhanced photocurrent densities. Under visible illumination, an increase of about 60 % in the photoelectrochemical activity is obtained for ZnO/TiO2 NTs with an about 2-nm-thick ZnO coating. PMID:26911568

  12. Calcium phosphate coating containing silver shows high antibacterial activity and low cytotoxicity and inhibits bacterial adhesion

    Surgical site infection is one of the serious complications of orthopedic implants. In order to reduce the incidence of implant-associated infections, we developed a novel coating technology of calcium phosphate (CP) containing silver (Ag), designated Ag-CP coating, using a thermal spraying technique. In this study, we evaluated the antibacterial efficacy and biological safety of this coating. In vitro antibacterial activity tests showed that the growths of Escherichia coli, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) are completely suppressed on Ag-CP coating. In vitro bacterial adherence tests revealed that the number of adherent bacteria on the surface of this coating is significantly less (p 2 CFU MRSA is inoculated. On the other hand, V79 Chinese hamster lung cells were found to grow on the Ag-CP coating as well as on the CP coating in a cytotoxicity test. These results indicate that the Ag-CP coating on the surface of orthopedic implants exhibits antibacterial activity and inhibits bacterial adhesion without cytotoxicity.

  13. Surface modification of TiO2 coatings by Zn ion implantation for improving antibacterial activities

    Xiaobing Zhao; Jiashen Yang; Jing You

    2016-02-01

    TiO$_2$ coating has been widely applied in orthopaedic and dental implants owing to its excellent mechanical and biological properties. However, one of the biggest complications of TiO$_2$ coating is implant-associated infections. The aim of this work is to improve the antibacterial activity of plasma-sprayed TiO$_2$ coatings by plasma immersion ion implantation (PIII) using zinc (Zn) ions. Results indicate that the as-sprayed TiO$_2$ coating is mainly composed of rutile phase. Zn-PIII modification does not change the phase compositions and the surface morphologies of TiO$_2$ coatings, while change their hydrophilicity. Zn-implanted TiO$_2$ coatings can inhibit the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), and the ability to inhibit S. aureus is greater than that to E. coli. Zn ion release and reactive oxygen species may be attributed to improving the antibacterial activity of TiO$_2$ coating. Therefore, Zn-PIII TiO$_2$ coatings on titanium suggest promising candidates for orthopaedic and dental implants.

  14. Preparation and photocatalytic activity of carbon coating TiO2 nanotubes

    Kong, Junhan; Wang, Yongqian; Wang, Zhengshu; Jia, Hanxiang

    2016-01-01

    Carbon coating TiO2 nanotubes (TNTs) were successfully prepared via anodic oxidation method as well as hydrothermal method, and their photocatalytic activity was evaluated by photodegrading methylene blue. The crystal shape of carbon coating TNTs was affected by the heating treatment temperature and they had a great enhancement on visible light absorption while contrasting with the primitive TNTs. As for photocatalytic activity of carbon coating TNTs in this study, we found that the photo-degradation rate of them can reach to 92.5% after 4 h when the concentration of glucose was 0.025 M. At last, a tentative mechanism for the enhancement of sunlight absorption was proposed.

  15. Cathodic electrophoretic deposition of bismuth oxide (Bi2O3) coatings and their photocatalytic activities

    Graphical abstract: Bismuth oxide (Bi2O3) coating has been prepared by cathodic electrophoretic deposition method and exhibits high photocatalytic activities for the degradation of Rhodamine B. - Highlights: • The nano-Bi2O3 coatings have been firstly successfully fabricated by EPD method. • The EPD deposition mechanism of Bi2O3 coatings is firstly given. • Deposition dynamics are investigated by regulating different deposition times and applied field strengths in detail. • Obtained coating show great photocatalytic activities for the degradation of Rhodamine B. - Abstract: In this study, cathodic electrophoretic deposition (EPD), a low cost, one-step and flexible method, has been successfully developed to prepare bismuth oxide (Bi2O3) coatings. Stable suspensions consisted of isopropyl alcohol and trace additive-polyethyleneimine. Deposition was achieved on the cathode at applied field strengths of 5–25 V mm−1 using a total solids loading of 0.5–2 g L−1 at ambient temperature and pressure. The deposition mechanism of Bi2O3 coatings was firstly given, and deposition kinetics were investigated in detail. The deposits were characterized qualitatively by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) observation, atomic force microscope (AFM), X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) analysis, respectively. Moreover, the photocatalytic activities of obtained coatings were evaluated through degradation of Rhodamine B under ultraviolet and visible light irradiation

  16. Electrochemically reduced graphene–gold nano particle composite on indium tin oxide for label free immuno sensing of estradiol

    Highlights: •Label free immunosensing of estradiol is demonstrated using graphene–AuNP composite fabricated on ITO transducer. •Continuous potential cycling reduction method selectively reduces the acid groups of the graphene oxide at pH 6.5. •The AuNP deposition induces change in the graphene orientation on the ITO surface and enhances the charge transport. -- Abstract: Electro reduced graphene and gold nano particle (ErG/AuNP) composite is prepared on indium tin oxide (ITO) surface. Characterization by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Raman spectroscopy (RS), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) techniques reveals the formation of vertical and flat oriented ErG films on the ITO. The AuNP deposition changes the flat oriented ErGs into vertical orientation indicated by the FESEM. Coherent interactions between the ITO, ErG and AuNPs are responsible for the discrete formation of vertical oriented hetero structures of ErG–AuNP composite on the ITO. Electrochemical properties are investigated using [Fe(CN)6]3−/4− and [Ru(NH3)]2+/3+ redox probes using cyclic voltammetry (CV). While the [Fe(CN)6]3−/4− shows fast reversible behavior, the [Ru(NH3)]2+/3+ reveals very slow charge transport on both ErG and ErG/AuNP films indicating the multi and compact graphene layer posses positive charge at pH 6.5 used for preparing these composites. Immuno sensing of breast cancer inducing hormone 17β-estradiol (E2) is demonstrated in presence of [Fe(CN)6]3−/4−. Estrone (E1) and estriol (E3) antigens are used as the controls. The near vertical immobilization of anti-estradiol-antibody enhances the lowest detection limit of 0.1 fmol and dynamic range of 1 × 10−3–0.1 × 10−12 M without any signal amplifiers. These results prove that the acid group of the GO is reduced selectively in controlled way by simple potential cycling method which

  17. Preparation, characterization and photocatalytic activity of a novel composite photocatalyst: Ceria-coated activated carbon

    In the present work, a novel composite photocatalyst ceria-coated activated carbon (CCAC) was prepared by a facile method. The composite photocatalyst was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and photocatalytic degradation of 4-chlorophenol (4-CP). A synergy effect for 4-CP degradation was observed because the activated carbon (AC) with strong adsorbent activity provided sites for the adsorption of 4-CP. Then, the adsorbed 4-CP can migrate continuously onto the surface of ceria particles and then degraded at there. Hydroquinone (HQ) and benzoquinone (BQ) were found to be the main intermediates of the photocatalytic 4-CP degradation with ceria or CCAC by HPLC measurement. The results suggested that the same reaction mechanism occurred in the presence of ceria or titania.

  18. Effect of Edible and Active Coating (with Rosemary and Oregano Essential Oils) on Beef Characteristics and Consumer Acceptability.

    Vital, Ana Carolina Pelaes; Guerrero, Ana; Monteschio, Jessica de Oliveira; Valero, Maribel Velandia; Carvalho, Camila Barbosa; de Abreu Filho, Benício Alves; Madrona, Grasiele Scaramal; do Prado, Ivanor Nunes

    2016-01-01

    The effects of an alginate-based edible coating containing natural antioxidants (rosemary and oregano essential oils) on lipid oxidation, color preservation, water losses, texture and pH of beef steaks during 14 days of display were studied. The essential oil, edible coating and beef antioxidant activities, and beef consumer acceptability were also investigated. The edible coatings decreased lipid oxidation of the meat compared to the control. The coating with oregano was most effective (46.81% decrease in lipid oxidation) and also showed the highest antioxidant activity. The coatings significantly decreased color losses, water losses and shear force compared to the control. The coatings had a significant effect on consumer perception of odor, flavor and overall acceptance of the beef. In particular, the oregano coating showed significantly high values (approximately 7 in a 9-point scale). Active edible coatings containing natural antioxidants could improve meat product stability and therefore have potential use in the food industry. PMID:27504957

  19. Surface modification of the core-shell type 198Au SiO2 Nano particles for an organic process media tracing study in refinery/petrochemical industries

    In this study, the surface of the Au SiO2 nano particle was modified from a hydrophilic type to hydrophobic by introducing 3,5-diphenylisocyanate in order to make use of the particle as a radiotracer in the flow dynamics study for petrochemical process units. The partitioning ratio of the hydrophobic particles between water and toluene was measured and compared as a function of time. It was observed that the partitioning ratio into an organic phase has been dramatically increased after the surface modification reaction. Consequently, the potential of its applicability to petrochemical: process diagnosis was enhanced

  20. Multiple scattering characteristic by a cluster of nano particles%纳米级颗粒系对激光的多次散射特性

    王海华; 孙贤明; 申晋; 刘伟

    2011-01-01

    激光在具有一定浓度的离散随机介质中传输时,将会经历多次散射.为了研究纳米级颗粒系对激光的多次散射特性,建立了一种考虑颗粒多次散射的累加模型.利用此模型研究了纳米级颗粒系对激光的多次散射特性,得到了反射和透射光强随着散射角以及光学厚度的变化关系.粒子的单次散射相函数采用瑞利相函数,并与根据Mie计算的相函数进行了比较.结果表明,反射光强随着光学厚度的增大而增大,漫透射光随着光学厚度的增大先增大后减少,且反射函数和透射函数对于同一光学厚度的颗粒层,具有相似的特性.该方法可用于纳米颗粒的多次散射计算.%The laser will undergo multiple scattering when it propagates in the discrete random media of certain concentration. In order to study the mulitiple scattering characterisitcs of laser scattered by a cluster of nano particles, an adding model which considered the laser multiple scattering by particles was built. The light multiple scattering characteristics of nano particles was studied based on this model. The reflection and transmission functions were obtained, and the relations between reflection and transmission function with the scattering angles and optical thickness were studied. The single scattering phase function of nano particles was replaced by Rayleigh phase function and compared with the function calculated by Mie. From the result, it can be concluded that the reflected light intensity increases with the increasing of the optical thickness, and diffused transmitted light intensity increases and then decreases with the increasing of the optical thickness. The reflection and transmission functions have similar characteristics for the particle layers with same optical thickness. The method can be used to calculate the multiple scattering characteristics of nano particles.

  1. Synthesis and Photocatalytic Activity of Anatase TiO2 Nanoparticles-coated Carbon Nanotubes

    Xie Yi

    2009-01-01

    Full Text Available Abstract A simple and straightforward approach to prepare TiO2-coated carbon nanotubes (CNTs is presented. Anatase TiO2 nanoparticles (NPs with the average size ~8 nm were coated on CNTs from peroxo titanic acid (PTA precursor even at low temperature of 100 °C. We demonstrate the effects of CNTs/TiO2 molar ratio on the adsorption capability and photocatalytic efficiency under UV–visible irradiation. The samples showed not only good optical absorption in visible range, but also great adsorption capacity for methyl orange (MO dye molecules. These properties facilitated the great enhancement of photocatalytic activity of TiO2 NPs-coated CNTs photocatalysts. The TiO2 NPs-coated CNTs exhibited 2.45 times higher photocatalytic activity for MO degradation than that of pure TiO2.

  2. Enhanced photoelectrochemical activity of vertically aligned ZnO-coated TiO2 nanotubes

    Vertically aligned ZnO-TiO2 hetero-nanostructures constructed of anatase TiO2 nanotubes (NTs) and wurtzite ZnO coatings are fabricated by atomic layer deposition of ZnO coatings on electrochemical anodization formed TiO2 NTs, and their photoelectrochemical activities are studied through photoelectrochemical and electrochemical characterization. Compared with bare TiO2 NTs, the transient photocurrent increases to over 1.5-fold for the annealed ZnO-coated TiO2 NTs under visible illumination. The ZnO-coated TiO2 NTs also show a longer electron lifetime, a lower charge-transfer resistance and a more negative flat-band potential than the bare TiO2 NTs, confirming the improved photoelectrochemical activity due to the enhanced charge separation

  3. Silicide Induced Surface Defects in FePt nanoParticle fcc-to-fct Thermally Activated Phase Transition

    Chen, S.; Lee, S. L.; André, P.

    2016-01-01

    Magnetic nanoparticles (MnPs) are relevant to a wide range of applications including high density information storage and magnetic resonance imaging to name but a few. Among the materials available to prepare MnPs, FePt is attracting growing attention. However, to harvest the strongest magnetic properties of FePt MnPs, a thermal annealing is often required to convert face-centered cubic as synthesized nPs into its tetragonal phase. Rarely addressed are the potential side effects of such treat...

  4. Structural Formation and Photocatalytic Activity of Magnetron Sputtered Titania and Doped-Titania Coatings

    Peter J. Kelly

    2014-10-01

    Full Text Available Titania and doped-titania coatings can be deposited by a wide range of techniques; this paper will concentrate on magnetron sputtering techniques, including “conventional” reactive co-sputtering from multiple metal targets and the recently introduced high power impulse magnetron sputtering (HiPIMS. The latter has been shown to deliver a relatively low thermal flux to the substrate, whilst still allowing the direct deposition of crystalline titania coatings and, therefore, offers the potential to deposit photocatalytically active titania coatings directly onto thermally sensitive substrates. The deposition of coatings via these techniques will be discussed, as will the characterisation of the coatings by XRD, SEM, EDX, optical spectroscopy, etc. The assessment of photocatalytic activity and photoactivity through the decomposition of an organic dye (methylene blue, the inactivation of E. coli microorganisms and the measurement of water contact angles will be described. The impact of different deposition technologies, doping and co-doping strategies on coating structure and activity will be also considered.

  5. Installation of a bitumen coating plant for high-activity concentrates

    Following the excellent results obtained on the industrial coating of radioactive sludges, the possibility of solidifying also the evaporation concentrates with bitumen has been considered. For high activity concentrates, the use of bitumen is however limited by two main parameters: temperature resistance, irradiation resistance. By making use of the characteristics of a blown bitumen, it has been possible to design a high activity coating pilot plant treating concentrations of several tens of curies per litre. This plant will make use of a screw-type extrusion machine capable of coating treated concentrates at a rate of 20 l/hr. Before being coated, the concentrates will be subjected to a coprecipitation treatment designed to make the radioelements insoluble. This installation will make possible, apart from technological studies, laboratory experiments on the coated material (measurements on self-heating, on electrical charges, on radiolytic gases, and also lixiviation tests. It is at present believed, on the basis of available data, that it is possible to coat concentrates having an activity of 20 Ci/l at a price of 1840 F per cubic metre. (authors)

  6. Electroless Ni-Co-P Coating of Cenospheres Using Ag(NH3)2+ Activator

    ZENGAi-xiang; XIONGWei-hao

    2004-01-01

    Electroless Ni-Co-P-coating of fly-ash cenosphere particles is demonstrated in the present investigation. The Electroless Ni-Co-P-coating process is modified by replacing the conventional sensitization and activation steps with only using activation step with Ag(NH3)2+ activator. The cenospheres are characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDX), X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS) during and after the coating process. Relatively uniform coating is obtained under the given coating conditions. The possible mechanism of electroless Ni-Co-P-coating of cenospheres utilizing Ag(NH3)2+ activator is suggested. The low density Ni-Co-P coated cenospheres may be utilized for manufacturing conducting polymers for EMI-shielding application and microwave absorbing materials.

  7. Hygroscopic growth and droplet activation of soot particles: uncoated, succinic or sulfuric acid coated

    S. Henning

    2012-05-01

    Full Text Available The hygroscopic growth and droplet activation of uncoated soot particles and such coated with succinic acid and sulfuric acid were investigated during the IN-11 campaign at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA facility. A GFG-1000 soot generator applying either nitrogen or argon as carrier gas and a miniCAST soot generator were utilized to generate soot particles. Different organic carbon (OC to black carbon (BC ratios were adjusted for the CAST-soot by varying the fuel to air ratio. The hygroscopic growth was investigated by means of the mobile Leipzig Aerosol Cloud Interaction Simulator (LACIS-mobile and two different Hygroscopicity Tandem Differential Mobility Analyzers (HTDMA, VHTDMA. Two Cloud Condensation Nucleus Counter (CCNC were applied to measure the activation of the particles. For the untreated soot particles neither hygroscopic growth nor activation was observed at a supersaturation of 1%, with exception of a partial activation of GFG-soot generated with argon as carrier gas. Coatings of succinic acid lead to a detectable hygroscopic growth of GFG-soot and enhanced the activated fraction of GFG- (carrier gas: argon and CAST-soot, whereas no hygroscopic growth of the coated CAST-soot was found. Sulfuric acid coatings led to an OC-content dependent hygroscopic growth of CAST-soot. Such a dependence was not observed for activation measurements. Coating with sulfuric acid decreased the amount of Polycyclic Aromatic Hydrocarbons (PAH, which were detected by AMS-measurements in the CAST-soot, and increased the amount of substances with lower molecular weight than the initial PAHs. We assume that these reaction products increased the hygroscopicity of the coated particles in addition to the coating substance itself.

  8. Hygroscopic growth and droplet activation of soot particles: uncoated, succinic or sulfuric acid coated

    S. Henning

    2011-10-01

    Full Text Available The hygroscopic growth and droplet activation of uncoated soot particles and such coated with succinic acid and sulfuric acid were investigated during the IN-11 campaign at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA facility. A GFG-1000 soot generator applying nitrogen, respectively argon as carrier gas and a miniCAST soot generator were utilized to generate soot particles. Different organic carbon (OC to black carbon (BC ratios were adjusted for the CAST-soot by varying the fuel to air ratio. The hygroscopic growth was investigated by means of the mobile Leipzig Aerosol Cloud Interaction Simulator (LACIS-mobile and two different Hygroscopicity Tandem Differential Mobility Analyzers (HTDMA, VHTDMA. Two Cloud Condensation Nucleus Counter (CCNC were applied to measure the activation of the particles. For the untreated soot particles neither hygroscopic growth nor activation was observed, with exception of a partial activation of GFG-soot generated with argon as carrier gas. Coatings of succinic acid lead to a detectable hygroscopic growth of GFG-soot and enhanced the activated fraction of GFG- (carrier gas: argon and CAST-soot, whereas no hygroscopic growth of the coated CAST-soot was found. Sulfuric acid coatings lead to an OC-content dependent hygroscopic growth of CAST-soot. Such a dependence was not observed for activation measurements. Coating with sulfuric acid decreased the amount of Polycyclic Aromatic Hydrocarbons (PAH, which were detected by AMS-measurements in the CAST-soot, and increased the amount of substances with lower molecular weight than the initial PAHs. We assume, that these reaction products increased the hygroscopicity of the coated particles in addition to the coating substance itself.

  9. Electrodeposition of metallic tungsten coating from binary oxide molten salt on low activation steel substrate

    Tungsten is considered a promising plasma facing armor material for future fusion devices. An electrodeposited metallic tungsten coating from Na2WO4–WO3 binary oxide molten salt on low activation steel (LAS) substrate was investigated in this paper. Tungsten coatings were deposited under various pulsed currents conditions at 1173 K in atmosphere. Cathodic current density and pulsed duty cycle were investigated for pulsed current electrolysis. The crystal structure and microstructure of tungsten coatings were characterized by X-ray diffractometry, scanning electron microscopy, and energy X-ray dispersive analysis techniques. The results indicated that pulsed current density and duty cycle significantly influence tungsten nucleation and electro-crystallization phenomena. The average grain size of the coating becomes much larger with increasing cathodic current density, which demonstrates that appropriate high cathodic current density can accelerate the growth of grains on the surface of the substrate. The micro-hardness of tungsten coatings increases with the increasing thickness of coatings; the maximum micro-hardness is 482 HV. The prepared tungsten coatings have a smooth surface, a porosity of less than 1%, and an oxygen content of 0.024 wt%

  10. Nano-particle size-dependent charging and electro-deposition in dielectric barrier discharges at atmospheric pressure for thin SiO{sub x} film deposition

    Jidenko, N [Equipe Decharges Electriques et Environnement du Laboratoire de Physique des Gaz et des Plasmas, UMR 8578 CNRS - Universite Paris-Sud Orsay, F-91405 Supelec, Plateau Moulon, F-91192 Gif Sur Yvette (France); Jimenez, C [Laboratoire de Genie Electrique de Toulouse, CNRS - Universite Paul Sabatier, Universite Paul Sabatier, 118 route de Narbonne, 31060 Toulouse (France); Massines, F [Laboratoire de Genie Electrique de Toulouse, CNRS - Universite Paul Sabatier, 118 route de Narbonne, 31060 Toulouse (France); Borra, J-P [Equipe Decharges Electriques et Environnement du Laboratoire de Physique des Gaz et des Plasmas, UMR 8578 CNRS - Universite Paris-Sud Orsay, F-91405 Supelec, Plateau Moulon, F-91192 Gif Sur Yvette (France)

    2007-07-21

    This paper focuses on charging and electro-deposition of nano-particles produced in a mixture of silane and nitrous oxide diluted in N{sub 2}, by dielectric barrier discharge (DBD) at atmospheric pressure for SiO{sub x} film deposition. Townsend discharge (TD) and filamentary discharge (FD) are compared with and without SiH{sub 4}. Without SiH{sub 4}, particles are produced by filament-surface interaction. Both filament-surface and plasma-silane interactions lead to bimodal particle size distributions from nucleation and agglomeration. With SiH{sub 4}, particle formation and growth imply the same mechanisms in TD and FD. Faster dynamics in FD are related to higher local volume energy density than in TD. From scanning electron microscope images of the film and measurements downstream of the DBD reactor, the diameter of the particle produced is below 50 nm. An analytical model of electro-collection in an ac electric field is used to investigate nano-particle charging. To account for selective electro-deposition leading to particles smaller than 50 nm being included in the layer and to particle size distribution measured downstream of the DBD, the same size-dependent charging and electro-deposition of particle are involved, with different charging dynamics in TD and FD.

  11. Study on characteristics of Ni-W-B composites containing CeO2 nano-particles prepared by pulse electrodeposition

    WANG Junli; XU Ruidong; ZHANG Yuzhi

    2012-01-01

    Ni-W-B composites containing CeO2 nano-particles on the surface of 45 steel were prepared by pulse electrodeposition,and the influence of pulse frequency,pulse duty circle and heat treatment temperature on the structures and properties were investigated.The results indicated that the pulse co-deposition of Ni,W,B and CeO2 nano-particles led to Ni-W-B/CeO2 composites possessing higher microhardness and better wear resistance when heat-treated at 400 ℃ for 1 h.The microhardness of 636 HV and the deposition rate of 0.0281 mm/h of the as-deposited alloy were the highest at pulse frequency of 1000 Hz,pulse duty circle of 10% and pulse average current density of 10 A/dm2.The composites were mainly in the amorphous state and were partially crystallized as-deposited,and the crystallization trend was strengthened when heat-treated at 400 ℃.Decreasing pulse duty cycle from 75% to 10% was favorable to the refinement in grain strctures and improvement ofmicrostructures.The crystal sizes of the composites were smaller by means of pulse electrodeposition.

  12. Activity and stability of RuO2-coated titanium anodes prepared via the alkoxide route

    VLADIMIR PANIC

    2006-11-01

    Full Text Available Titanium anodes with an active RuO2 coating of two different thicknesses were prepared from the oxide suspended in ethanol ("ink" method, while the oxide itself was synthesized by the hydrolysis of ruthenium ethoxide in an ethanolic solution (alkoxide route. The morphology of prepared oxide was examined by scanning electron microscopy. The electrochemical properties of the prepared Ti/RuO2 anodes, involving their cyclic voltammetric behavior in H2SO4 and NaCl solutions, activity in the chlorine and oxygen evolution reaction, impedance behavior in H2SO4, and stability during electrolysis in dilute chloride solutions, were investigated. The performances of the anodes are compared to those of a Ti/RuO2 anode prepared by the sol–gel procedure from an oxide sol obtained by the forced hydrolysis of ruthenium chloride in acid solution. The anodes prepared via the alkoxide route showed a higher capacitance and activity for the chlorine evolution reaction than the anode prepared by the inorganic sol–gel procedure. The results of the stability test showed that the utilization of the coating active material is better when the anodes were prepared via the alkoxide route than via the inorganic sol–gel procedure, particularly for anodes with a smallermass of coating. The different rates of loss of activity indicate a degradation mechanism for the anodes prepared via the alkoxide route in which electrochemical dissolution of RuO2 from the coating surface prevails over the growth of an insulating TiO2 layer in the coating/Ti substrate interphase. The effect of RuO2 dissolution from the coating surface increases with increasing coating mass.

  13. Improved cell activity on biodegradable photopolymer scaffolds using titanate nanotube coatings

    The development of bioactive materials is in the premise of tissue engineering. For several years, surface functionalization of scaffolds has been one of the most promising approaches to stimulate cellular activity and finally improve implant success. Herein, we describe the development of a bioactive composite scaffold composed of a biodegradable photopolymer scaffold and titanate nanotubes (TNTs). The biodegradable photopolymer scaffolds were fabricated by applying mask-projection excimer laser photocuring at 308 nm. TNTs were synthesized and then spin-coated on the porous scaffolds. Upon culturing fibroblast cells on scaffolds, we found that nanotubes coating affects cell viability and proliferation demonstrating that TNT coatings enhance cell growth on the scaffolds by further improving their surface topography. - Highlights: • Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. • Titanate nanotube deposition was carried out without binding compounds or additives. • Titanate nanotube coatings enhanced cell viability and proliferation

  14. Improved cell activity on biodegradable photopolymer scaffolds using titanate nanotube coatings

    Beke, S., E-mail: szabolcs.beke@iit.it [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Barenghi, R. [IEIIT, National Research Council (CNR), Via De Marini 6, 16149 Genova (Italy); Farkas, B.; Romano, I. [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632 Pécs (Hungary); Scaglione, S. [IEIIT, National Research Council (CNR), Via De Marini 6, 16149 Genova (Italy); Brandi, F. [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, 56124-Pisa (Italy)

    2014-11-01

    The development of bioactive materials is in the premise of tissue engineering. For several years, surface functionalization of scaffolds has been one of the most promising approaches to stimulate cellular activity and finally improve implant success. Herein, we describe the development of a bioactive composite scaffold composed of a biodegradable photopolymer scaffold and titanate nanotubes (TNTs). The biodegradable photopolymer scaffolds were fabricated by applying mask-projection excimer laser photocuring at 308 nm. TNTs were synthesized and then spin-coated on the porous scaffolds. Upon culturing fibroblast cells on scaffolds, we found that nanotubes coating affects cell viability and proliferation demonstrating that TNT coatings enhance cell growth on the scaffolds by further improving their surface topography. - Highlights: • Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. • Titanate nanotube deposition was carried out without binding compounds or additives. • Titanate nanotube coatings enhanced cell viability and proliferation.

  15. Capacitance enhancement of polyaniline coated curved-graphene supercapacitors in a redox-active electrolyte

    Chen, Wei

    2013-01-01

    We show, for the first time, a redox-active electrolyte in combination with a polyaniline-coated curved graphene active material to achieve significant enhancement in the capacitance (36-92% increase) compared to supercapacitors that lack the redox-active contribution from the electrolyte. The supercapacitors based on the redox-active electrolyte also exhibit excellent rate capability and very long cycling performance (>50 000 cycles). This journal is © The Royal Society of Chemistry.

  16. Corrosion-Activated Micro-Containers for Environmentally Friendly Corrosion Protective Coatings

    Li, Wenyan; Buhrow, J. W.; Zhang, X.; Johnsey, M. N.; Pearman, B. P.; Jolley, S. T.; Calle, L. M.

    2016-01-01

    This work concerns the development of environmentally friendly encapsulation technology, specifically designed to incorporate corrosion indicators, inhibitors, and self-healing agents into a coating, in such a way that the delivery of the indicators and inhibitors is triggered by the corrosion process, and the delivery of self-healing agents is triggered by mechanical damage to the coating. Encapsulation of the active corrosion control ingredients allows the incorporation of desired autonomous corrosion control functions such as: early corrosion detection, hidden corrosion detection, corrosion inhibition, and self-healing of mechanical damage into a coating. The technology offers the versatility needed to include one or several corrosion control functions into the same coating.The development of the encapsulation technology has progressed from the initial proof-of-concept work, in which a corrosion indicator was encapsulated into an oil-core (hydrophobic) microcapsule and shown to be delivered autonomously, under simulated corrosion conditions, to a sophisticated portfolio of micro carriers (organic, inorganic, and hybrid) that can be used to deliver a wide range of active corrosion ingredients at a rate that can be adjusted to offer immediate as well as long-term corrosion control. The micro carriers have been incorporated into different coating formulas to test and optimize the autonomous corrosion detection, inhibition, and self-healing functions of the coatings. This paper provides an overview of progress made to date and highlights recent technical developments, such as improved corrosion detection sensitivity, inhibitor test results in various types of coatings, and highly effective self-healing coatings based on green chemistry. The NASA Kennedy Space Centers Corrosion Technology Lab at the Kennedy Space Center in Florida, U.S.A. has been developing multifunctional smart coatings based on the microencapsulation of environmentally friendly corrosion

  17. Recruitment of epidermal growth factor receptors into coated pits requires their activated tyrosine kinase

    1995-01-01

    EGF-receptor (EGF-R) tyrosine kinase is required for the down- regulation of activated EGF-R. However, controversy exists as to whether ligand-induced activation of the EGF-R tyrosine kinase is required for internalization or for lysosomal targeting. We have addressed this issue using a cell-free assay that selectively measures the recruitment of EGF-R into coated pits. Here we show that EGF bound to wild-type receptors is efficiently sequestered in coated pits. In contrast, sequestration of ...

  18. Electrohydrodynamic coating of metal with nano-sized hydroxyapatite.

    Li, Xiang; Huang, Jie; Ahmad, Zeeshan; Edirisinghe, Mohan

    2007-01-01

    Electrohydrodynamic spray deposition of a hydroxyapatite (HA) suspension consisting of nano-particles has been used to create a hydroxyapatite coating comprising of nanostructured surface topography. Preliminary coating experiments were carried out on an Al substrate and 30 s was found to be the most appropriate coating time. HA coating on titanium for this duration was found to be well-bonded to the substrate after heat-treatment. A thickness of 2 mum was achieved in 30 s and formation of a bone-like apatite on the surface was detected after incubation of the heat-treated coated Ti in simulated body fluid. Therefore, we have uncovered a new procedure by which nano-biomaterials can be deposited on real orthopedic substrates to prepare bioactive thin coatings in a simple and easy manner. PMID:18032815

  19. Active cloaking of resonant coated inclusions for waves in membranes and Kirchhoff plates

    O'Neill, J; McPhedran, R C; Movchan, A B; Movchan, N V; Moggach, C Henderson

    2015-01-01

    The dynamic response of a coated inclusion is considered in the context of active cloaking. The active cloak is achieved for a coated inclusion in the presence of membrane and flexural waves. In this paper, we investigate the design of an active cloak for a coated inclusion in three frequency regimes: the very low frequency (monopole dominated) range, the intermediate range, and the higher frequency range in which scattering resonances occur. In the first of these ranges, we validate previous work, which resulted in a simple mass-compensation design for the monopole scatterer, while in the second and third ranges, a combination of the use of an appropriate coating and the appropriate choice of the amplitudes of the active cloaking sources is necessary. We show that such cloaking can indeed be effective in the region of strong scattering resonances. We give closed form analytic expressions for the required amplitudes of the active cloaking sources in the three frequency regions and provide asymptotic estimates...

  20. Effects of Zn Content on Crystal Structure, Cytocompatibility, Antibacterial Activity, and Chemical Stability in Zn-Modified Calcium Silicate Coatings

    Li, Kai; Yu, Jiangming; Xie, Youtao; Huang, Liping; Ye, Xiaojian; Zheng, Xuebin

    2013-08-01

    In our previous study, Zn-modified calcium silicate coatings possess not only excellent chemical stability but also well antibacterial activity. Still, effects of zinc content on these properties and cytocompatibility remain unclear. In this paper, two kinds of Zn-modified calcium silicate coatings (ZC0.3, ZC0.5) were fabricated on Ti-6Al-4V substrates via plasma spraying technology. X-ray diffraction results and transmission electron microscopy observations showed that the ZC0.5 coating was composed of pure hardystonite (Ca2ZnSi2O7) phase, while, besides Ca2ZnSi2O7 phase, the amorphous CaSiO3 phase was also detected in the ZC0.3 coating. Chemical stability in Tris-HCl buffer solution and antibacterial activity of the Zn-modified calcium silicate coatings increased with an increase in zinc content. In vitro cytocompatibility evaluation demonstrated that the proliferation and alkaline phosphatase activity and collagen type I (COLI) secretion of osteoblast-like MC3T3-E1 cells on Zn-modified coatings were significantly enhanced compared to the Zn-free coating and Ti-6Al-4V control, and no cytotoxicity appeared on Zn-modified coatings. The better antibacterial activity and the enhanced capability to promote MC3T3-E1 cells differentiation of Zn-modified coatings should be attributed to the slow and constant Zn2+ releasing from the coatings.

  1. Experimental analysis of tablet properties for discrete element modeling of an active coating process.

    Just, Sarah; Toschkoff, Gregor; Funke, Adrian; Djuric, Dejan; Scharrer, Georg; Khinast, Johannes; Knop, Klaus; Kleinebudde, Peter

    2013-03-01

    Coating of solid dosage forms is an important unit operation in the pharmaceutical industry. In recent years, numerical simulations of drug manufacturing processes have been gaining interest as process analytical technology tools. The discrete element method (DEM) in particular is suitable to model tablet-coating processes. For the development of accurate simulations, information on the material properties of the tablets is required. In this study, the mechanical parameters Young's modulus, coefficient of restitution (CoR), and coefficients of friction (CoF) of gastrointestinal therapeutic systems (GITS) and of active-coated GITS were measured experimentally. The dynamic angle of repose of these tablets in a drum coater was investigated to revise the CoF. The resulting values were used as input data in DEM simulations to compare simulation and experiment. A mean value of Young's modulus of 31.9 MPa was determined by the uniaxial compression test. The CoR was found to be 0.78. For both tablet-steel and tablet-tablet friction, active-coated GITS showed a higher CoF compared with GITS. According to the values of the dynamic angle of repose, the CoF was adjusted to obtain consistent tablet motion in the simulation and in the experiment. On the basis of this experimental characterization, mechanical parameters are integrated into DEM simulation programs to perform numerical analysis of coating processes. PMID:23354469

  2. Retaining Oxidative Stability of Emulsified Foods by Novel Nonmigratory Polyphenol Coated Active Packaging.

    Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2016-07-13

    Oxidation causes lipid rancidity, discoloration, and nutrient degradation that decrease shelf life of packaged foods. Synthetic additives are effective oxidation inhibitors, but are undesirable to consumers who prefer "clean" label products. The aim of this study was to improve oxidative stability of emulsified foods by a novel nonmigratory polyphenol coated active packaging. Polyphenol coatings were applied to chitosan functionalized polypropylene (PP) by laccase assisted polymerization of catechol and catechin. Polyphenol coated PP exhibited both metal chelating (39.3 ± 2.5 nmol Fe(3+) cm(-2), pH 4.0) and radical scavenging (up to 52.9 ± 1.8 nmol Trolox eq cm(-2)) capacity, resulting in dual antioxidant functionality to inhibit lipid oxidation and lycopene degradation in emulsions. Nonmigratory polyphenol coated PP inhibited ferric iron promoted degradation better than soluble chelators, potentially by partitioning iron from the emulsion droplet interface. This work demonstrates that polyphenol coatings can be designed for advanced material chemistry solutions in active food packaging. PMID:27310107

  3. Tuning the surface enhanced Raman scattering activity of gold nanocubes by silver coating

    Ding, Shu-Jun; Zhu, Jian

    2015-12-01

    Colloidal gold nanocubes coated with a silver nanoshell have been synthesized via the seed mediated growth method. By changing the volume of gold seed and silver nitrate, both the edge length of gold nanocube and the thickness of silver shell could be fine-tuned. The surface-enhanced Raman scattering (SERS) activity of these core-shell structural Au-Ag bimetallic nanocubes has also been investigated by using the rhodamine 6G (R6G) as Raman active probe. It has been found the SERS activity of the silver-coated gold nanocubes greatly depends on their geometry factors. By decreasing the edge length of gold nanocubes or increasing the silver coating thickness, the SERS activity has been greatly enhanced. By comparing with other Raman bands of R6G, the enhancement of the Raman peak corresponding to the Csbnd Csbnd C ring in-plane vibration mode is more sensitive to the geometries of the nanostructure. These improved SERS properties of silver-coated gold nanocubes provide potential application for biologic and chemical sensing based on Raman spectroanalysis.

  4. A Hemoperfusion Column Based on Activated Carbon Granules Coated with an Ultrathin Membrane of Cellulose Acetate

    Tijssen, Johan; Bantjes, Adriaan; Doorn , van Albert W.J.; Feijen, Jan; Dijk, van Boudewijn; Vonk, Carel R.; Dijkhuis, Ido C.

    1979-01-01

    A hemoperfusion system has been developed which makes use of activated carbon encapsulated with cellulose acetate. Studies have revealed that there are no stagnant flow regions in the column, there i? minimal particle release and the coating is 30 Å thick. The relationships between pore size, pore v

  5. Livestock air treatment using PVA-coated powdered activated carbon biofilter

    The efficacy of polyvinyl alcohol (PVA) biofilters was studied using bench-scale biofilters and air from aerobically-treated swine manure. The PVA-coated powdered activated carbon particles showed excellent properties as a biofiltration medium: water holding capacity of 1.39 g H2O/g-dry PVA; wet por...

  6. Coatings of active and heat-resistant cobalt-aluminium xerogel catalysts.

    Schubert, Miriam; Schubert, Lennart; Thomé, Andreas; Kiewidt, Lars; Rosebrock, Christopher; Thöming, Jorg; Roessner, Frank; Bäumer, Marcus

    2016-09-01

    The application of catalytically coated metallic foams in catalytic processes has a high potential for exothermic catalytic reactions such as CO2 methanation or Fischer-Tropsch synthesis due to good heat conductivity, improved turbulent flow properties and high catalyst efficiencies. But the preparation of homogenous catalyst coats without pore blocking is challenging with conventional wash coating techniques. Here, we report on a stable and additive free colloidal CoAlOOH suspension (sol) for the preparation of catalytically active Co/Al2O3 xerogel catalysts and coatings. Powders with 18wt% Co3O4 prepared from this additive free synthesis route show a catalytic activity in Fischer-Tropsch synthesis and CO2 methanation which is similar to a catalyst prepared by incipient wetness impregnation (IWI) after activating the material under flowing hydrogen at 430°C. Yet, the xerogel catalyst exhibits a much higher thermal stability as compared to the IWI catalyst, as demonstrated in catalytic tests after different heat agings between 430°C and 580°C. It was also found that the addition of polyethylene glycol (PEG) to the sol influences the catalytic properties of the formed xerogels negatively. Only non-reducible cobalt spinels were formed from a CoAlOOH sol with 20wt% PEG. Metallic foams with pores sizes between 450 and 1200μm were coated with the additive free CoAlOOH sol, which resulted in homogenous xerogel layers. First catalytic tests of the coated metal foams (1200μm) showed good performance in CO2 methanation. PMID:27240245

  7. Preparation of biocatalytic nanofibers with high activity and stability via enzyme aggregate coating on polymer nanofibers

    Kim, Byoung Chan; Nair, Sujith; Kim, Jungbae; Kwak, Ja Hun; Grate, Jay W.; Kim, Seong H.; Gu, Man Bock

    2005-04-01

    We have developed a unique approach for the fabrication of enzyme coating on the surface of electrospun polymer nanofibers. This approach employs covalent attachment of seed enzymes onto nanofibers, followed by the glutaraldehyde treatment that crosslinks additional enzymes onto the seed enzyme molecules. These crosslinked enzyme aggregates, covalently attached to the nanofibers via seed enzyme linker, would improve not only the enzyme activity due to increased enzyme loading, but also the enzyme stability. To demonstrate the principle of concept, we fabricated the coating of alpha-chymotrypsin (CT) on the nanofibers electrospun from a mixture of polystyrene and poly(styrene-co-maleic anhydride). The addition of poly(styrene-co-maleic anhydride) makes it much easier to attach the seed enzyme molecules onto electrospun nanofibers without any rigorous functionalization of nanofibers for the attachment of enzymes. The initial activity of final CT coating was 17 and 9 times higher than those of simply-adsorbed CT and covalently-attached CT, respectively. While adsorbed and covalently-attached CT resulted in a serious enzyme leaching during initial incubation in a shaking condition, the CT coating did not show any leaching from the beginning of incubation in the same condition. As a result, the enzyme stability of CT coating was impressively improved with a half-life of 686 days under rigorous shaking while the half-life of covalently-attached CT was only 21 hours. This new approach of enzyme coating with high stability and activity will make a great impact in various applications of enzymes such as bioconversion, bioremediation, and biosensors.

  8. Sintering by hot isostatic pressing (HIP) and spark plasma sintering (SPS) of silicon carbide (SiC) nano-particles synthesized by laser pyrolysis pilot scale

    Pure or with sintering additives (Al2O3 + Y2O3) SiC nano-particles (20 nm) synthesised by laser pyrolysis at pilot scale were first cold pressed under 1 GPa and then sintered by Hot Isostatic Pressing (HIP) and Spark Plasma Sintering (SPS). Pure SiC samples densified by HIP have a higher density (95%) than SPS ones (80%). With help of sintering additives, both HIP and SPS samples are near theoretical density. Smaller grain size were observed for HIP pellets (pure ∼35 nm and with additives ∼100 to 200 nm). Whereas SPS samples grain size were between 100 nm and 1 m. A primary mechanical properties study demonstrates a hardness (28 GPa) and a toughness (6.5 MPa m1/2) optimum when crystallite size is around 200 nm. (authors)

  9. Influence of nano-particle coherency degree on the coarsening resistivity of the nano-oxide particles of Fe–14Cr–1W ODS alloys

    Zhong, S.Y., E-mail: shengyi.zhong@sjtu.edu.cn [DSM/IRAMIS/LLB CEA Saclay, 91191 Gif-sur-Yvette (France); Ribis, J.; Lochet, N.; Carlan, Y. de [DMN/SRMA/LTMEx CEA Saclay, 91191 Gif-sur-Yvette (France); Klosek, V.; Mathon, M.H. [DSM/IRAMIS/LLB CEA Saclay, 91191 Gif-sur-Yvette (France)

    2014-12-15

    High chrome oxide dispersion strengthened (ODS) ferritic alloys exhibit a high mechanical resistance at high temperature as well as high resistance to radiation damage due to its high density of Y–Ti–O nano clusters. In order to correlate the coarsening resistance of Fe–14Cr–1W ODS alloys with nano-particle coherency degree and nominal content of Y and Ti, SANS analysis and TEM investigations are used to characterize the size distributions of nano oxides and the interface configuration before and after heat treatment at 1300 °C. The result indicates that the ratio of Ti/Y plays an important role on the coarsening kinetics. The nano oxides of the sample with a high ratio of Ti/Y superior to 1 are more stable owing to the minimizing of the interfacial energy particle/matrix.

  10. Preparation and Characterization of SnO2 Nano-particles%SnO2纳米粒子的制备与表征

    孙明; 余林; 郝志峰; 孙建

    2005-01-01

    The SnO2 nano-particles with rutile structure were prepared by a Water/Oil (W/O) microemulsion system, composed of Triton X-100+1-hexanol/Cyclohexane/Water. The particles were also compared with that synthesized by citric acid method. The powders were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and infrared spectroscopy (IR). The result showed that the SnO2 particles prepared by microemulsion had fine shape and narrow range of particle size distribution. The crystallite size calcined at 600℃ was 11.49 nm,while the crystallite size prepared by citric acid method was about 17.4 nm.

  11. Haematological and Histological Alterations Induced in Rats by Gamma Rays and the Therapeutic Action of Phenolic compounds in Nano Particles Form

    Phenolic compounds as para-coumaric acids and caffeic acids are natural compounds in nano form as Zinc Coumarate Nano Particles (ZnCoum. NPs) and Zinc Caffeiate Nano Particles (ZnCaf. NPs) have been shown to confer various biological effects, anticancer, enhance immune system and antioxidant properties. The present study was undertaken to evaluate the radio protective and possess ability of ZnCoum.NPs and ZnCaf.NPs against whole body γ-irradiation with a dose of 3 Gy, 4 times, every week up to 12 Gy. ZnCoum. NPs and ZnCaf. NPs were given to rats by intraperitoneal injection at a concentration of 5 mg/kg and 15 mg/kg body weight respectively, for 7 successive days, post irradiation for (ZnCoum. NPs + ZnCaf. NPs) and [(ZnCoum. NPs + ZnCaf. NPs) + Irradiated] groups and for 30 successive days for (ZnCoum. NPs + ZnCaf. NPs), [(ZnCoum. NPs + ZnCaf. NPs) + Irradiated] and [Irradiated + (ZnCoum. NPs + ZnCaf. NPs)] groups. The results indicated that γ- irradiated group caused a significant decrease of body weight and hematological level disorders. Histological study also revealed that γ- irradiation induced vacuoles degeneration and necrosis of a great number of hepatocytes together with several hemorrhage and interstitial oedema. Whilst, the treatment with ZnCoum. NPs + ZnCaf. NPs pre or post-exposure to γ- ray protected blood cells and hepatocytes from harmful effects of γ- radiation.

  12. Haematological and Histological Alterations Induced in Rats by Gamma Rays and the Therapeutic Action of Phenolic compounds in Nano Particles Form

    Phenolic compounds as para-coumaric acids and caffeic acids are natural compounds in nano form as Zinc Coumarate Nano Particles (ZnCoum. NPs) and Zinc Caffeiate Nano Particles (ZnCaf. NPs) have been shown to confer various biological effects, anticancer, enhance immune system and antioxidant properties. The present study was undertaken to evaluate the radio protective and possess ability of ZnCoum.NPs and ZnCaf.NPs against whole body γirradiation with a dose of 3 Gy, 4 times, every week up to 12 Gy. ZnCoum.NPs and ZnCaf. NPs were given to rats by intraperitoneal injection at a concentration of 5 mg/kg and 15 mg/kg body weight respectively, for 7 successive days, post irradiation for (ZnCoum. NPs + ZnCaf. NPs) and [(ZnCoum. NPs + ZnCaf. NPs) + Irradiated] groups and for 30 successive days for (ZnCoum. NPs + ZnCaf. NPs), [(ZnCoum. NPs + ZnCaf. NPs) + Irradiated] and [Irradiated + (ZnCoum. NPs + ZnCaf. NPs)] groups. The results indicated that γ- irradiated group caused a significant decrease of body weight and hematological level disorders. Histological study also revealed that γ-irradiation induced vacuoles degeneration and necrosis of a great number of hepatocytes together with several hemorrhage and interstitial oedema. Whilst, the treatment with ZnCoum. NPs + ZnCaf. NPs pre or post-exposure to γ-ray protected blood cells and hepatocytes from harmful effects of γ-radiation.

  13. Formation of Li3O4 nano particles in the discharge products of non-aqueous lithium-oxygen batteries leads to lower charge overvoltage.

    Shi, L; Xu, A; Zhao, T S

    2015-11-28

    Density functional theory calculations are made for bulk thermodynamic properties and surface energies of Li2O2, a primary discharge product, and Li3O4, a possible byproduct in the discharge products, of the non-aqueous lithium-oxygen batteries. Results show that the standard formation Gibbs free energy of bulk Li3O4 is marginally higher than that of Li2O2, but the surface energy of Li3O4 is much lower. Low surface energy results in both lowered nucleation energy and formation Gibbs free energy in the nanometer regime, allowing the Li3O4 nano particles to nucleate ahead of Li2O2 during the discharge process and to exist stably when particle sizes are smaller than about 40 nm. The scanning transmission electron microscopy (STEM) image of Li3O4 crystals is simulated and compared with the measured STEM image of the discharge product particles. The consistency between the simulated and measured STEM images suggests that the Li3O4 phase can exist stably as a discharge product. The energy profile of the oxygen evolution reaction (OER) occurring on the most abundant surfaces of Li3O4 is also calculated. The predicted overpotential for the OER on the {0001} surface (0.30 V) shows a good agreement with experimental data. The presence of more electronically conductive Li3O4 nano particles in the primary discharge product Li2O2 tends to decrease the charge overvoltage of the batteries, explaining why the lower voltage area (oxygen pressure or a decrease in temperature enhances the stability of the Li3O4 phase and increase the proportion of the Li3O4 phase in the discharge products, consequently leading to a lower overall charge overvoltage. PMID:26486991

  14. Extensive FE-SEM/EDS, HR-TEM/EDS and ToF-SIMS studies of micron- to nano-particles in anthracite fly ash

    The generation of anthropogenic carbonaceous matter and mixed crystalline/amorphous mineral ultrafine/nano-particles in the 1 to 100 nm size range by worldwide coal power plants represents serious environmental problems due to their potential hazards. Coal fly ash (CFA) that resulted from anthracite combustion in a Portuguese thermal power plant was studied in this work. The physico-chemical characterization of ultrafine/nano-particles present in the CFA samples and their interaction with environment are the aim of this study. The methodologies applied for this work were field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy with energy dispersive X-ray spectroscopy (HR-TEM/EDS) and time of flight secondary ion mass spectrometry (ToF-SIMS). Some hazardous volatile elements, C, N, S and Hg contents were also determined in the studied samples. Generally, the CFA samples comprise carbonaceous, glassy and metallic solid spheres with some containing mixed amorphous/crystalline phases. The EDS analysis coupled with the FE-SEM and HR-TEM observations of the fly ash particles with 100 to 0.1 nm demonstrates that these materials contain a small but significant proportion of encapsulated HVEs. In addition, the presence of abundant multi-walled carbon nanotubes (MWCNTs) and amorphous carbon particles, both containing hazardous volatile elements (HVEs), was also evidenced by the FE-SEM/EDS and HR-TEM/EDS analysis. A wide range of organic and inorganic compounds was determined by chemical maps obtained in ToF-SIMS analysis. - Highlights: ► We examine changes in the level of ultrafine and nanoparticles of coal mining. ► Increasing geochemical information will increase human health information in this area. ► Electron bean and Tof-SIMS increase area information

  15. Extensive FE-SEM/EDS, HR-TEM/EDS and ToF-SIMS studies of micron- to nano-particles in anthracite fly ash

    Ribeiro, Joana [Centro de Geologia, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); DaBoit, Kátia [Institute of Environmental Research and Human Development, IPADHC, Capivari de Baixo, Santa Catarina (Brazil); Flores, Deolinda [Centro de Geologia, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Departamento de Geociências, Ambiente e Ordenamento do Território, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Kronbauer, Marcio A. [Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Silva, Luis F.O., E-mail: felipeqma@hotmail.com [Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Environmental Science and Nanotechnology Department, Catarinense Institute of Environmental Research and Human Development, IPADHC, Capivari de Baixo, Santa Catarina (Brazil)

    2013-05-01

    The generation of anthropogenic carbonaceous matter and mixed crystalline/amorphous mineral ultrafine/nano-particles in the 1 to 100 nm size range by worldwide coal power plants represents serious environmental problems due to their potential hazards. Coal fly ash (CFA) that resulted from anthracite combustion in a Portuguese thermal power plant was studied in this work. The physico-chemical characterization of ultrafine/nano-particles present in the CFA samples and their interaction with environment are the aim of this study. The methodologies applied for this work were field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy with energy dispersive X-ray spectroscopy (HR-TEM/EDS) and time of flight secondary ion mass spectrometry (ToF-SIMS). Some hazardous volatile elements, C, N, S and Hg contents were also determined in the studied samples. Generally, the CFA samples comprise carbonaceous, glassy and metallic solid spheres with some containing mixed amorphous/crystalline phases. The EDS analysis coupled with the FE-SEM and HR-TEM observations of the fly ash particles with 100 to 0.1 nm demonstrates that these materials contain a small but significant proportion of encapsulated HVEs. In addition, the presence of abundant multi-walled carbon nanotubes (MWCNTs) and amorphous carbon particles, both containing hazardous volatile elements (HVEs), was also evidenced by the FE-SEM/EDS and HR-TEM/EDS analysis. A wide range of organic and inorganic compounds was determined by chemical maps obtained in ToF-SIMS analysis. - Highlights: ► We examine changes in the level of ultrafine and nanoparticles of coal mining. ► Increasing geochemical information will increase human health information in this area. ► Electron bean and Tof-SIMS increase area information.

  16. Fabrication of nano-structured TiO2 coatings using a microblast deposition technique

    McDonnell, Kevin; English, Niall J.; Stallard, Charlie P.; et al.

    2013-01-01

    Micron thick titanium dioxide (TiO2) coatings exhibiting a nano-structured, anatase, meso-porous structure were successfully deposited across a range of polymer, conductive glass and metallic substrates at low velocities using a microblasting technique. This process was conducted at atmospheric pressure using compressed air as the carrier gas and commercially available agglomerated nano particles of TiO2 as the feedstock. An examination of the effect of impact kinetics on the agglomerated pow...

  17. Electrodeposition and Corrosion Resistance Properties of Zn-Ni/TiO2 Nano composite Coatings

    B. M. Praveen; T. V. Venkatesha

    2011-01-01

    Nano sized TiO2 particles were prepared by sol-gel method. TiO2 nano particles were dispersed in zinc-nickel sulphate electrolyte and thin film of Zn-Ni-TiO2 composite was generated by electrodeposition on mild steel plates. The effect of TiO2 on the corrosion behavior and hardness of the composite coatings was investigated. The film was tested for its corrosion resistance ...

  18. Double-diffusive natural convective boundary layer flow in a porous medium saturated with a nano-fluid over a vertical plate: Prescribed surface heat, solute and nano-particle fluxes

    Khan, W.A. [Department of Engineering Sciences, National University of Sciences and Technology, Karachi 75350 (Pakistan); Aziz, A. [Department of Mechanical Engineering, School of Engineering and Applied Science, Gonzaga University, Spokane, WA 99258 (United States)

    2011-11-15

    The Buongiorno model [16] has been used to study the double-diffusive natural convection from a vertical plate to a porous medium saturated with a binary base fluid containing nano-particles. The model identifies the Brownian motion and thermophoresis as the primary mechanisms for enhanced convection characteristics of the nano-fluid. The behavior of the porous medium is described by the Darcy model. The vertical surface has the heat, mass and nano-particle fluxes each prescribed as a power law function of the distance along the wall. The transport equations are transformed into four nonlinear, coupled similarity equations containing eight dimensionless parameters. These equations are solved numerically to obtain the velocity, temperature, solute concentration and nano-particle concentration in the respective boundary layers. Results are presented to illustrate the effects of various parameters including the exponent of the power law describing the imposed surface fluxes on the heat and mass transfer characteristics of the flow. These results are supplemented with the data for the reduced Nusselt number and the two reduced Sherwood numbers, one for the solute and the other for the nano-particles. (authors)

  19. Development of anti-corrosion coating on low activation materials against fluoridation and oxidation in Flibe blanket environment

    W coating by vacuum plasma spray process and Cr coating by chromizing process were performed on fusion low activation materials, JLF-1 ferritic steel and NIFS-HEAT-2 vanadium alloy. The present study discusses feasibility of the coatings as anti-corrosion coating against fluoridation in Flibe for fusion low activation materials. Coatings were characterized by microstructural analysis and examination on chemical stability by corrosion tests. The corrosion tests were conducted with H2O-47% HF solution at RT and He-1% HF-0.06 H2O gas mixture at 823 K to simulate fluoridation and oxidation in Flibe. The coatings presented suppression of fluoride formation compared with JLF-1 or NIFS-HEAT-2, however weight loss due to WF6 formation was induced, and much Cr2O3 was formed.

  20. In vitro antiplasmodial activity of PDDS-coated metal oxide nanoparticles against Plasmodium falciparum

    Jacob Inbaneson, Samuel; Ravikumar, Sundaram

    2013-06-01

    Malaria is the most important parasitic disease, leading to annual death of about one million people and the Plasmodium falciparum develops resistant to well-established antimalarial drugs. The newest antiplasmodial drug from metal oxide nanoparticles helps in addressing this problem. Commercial nanoparticles such as Fe3O4, MgO, ZrO2, Al2O3 and CeO2 coated with PDDS and all the coated and non-coated nanoparticles were screened for antiplasmodial activity against P. falciparum. The Al2O3 nanoparticles (71.42 ± 0.49 μg ml-1) showed minimum level of IC50 value and followed by MgO (72.33 ± 0.37 μg ml-1) and Fe3O4 nanoparticles (77.23 ± 0.42 μg ml-1). The PDDS-Fe3O4 showed minimum level of IC50 value (48.66 ± 0.45 μg ml-1), followed by PDDS-MgO (60.28 ± 0.42 μg ml-1) and PDDS-CeO2 (67.06 ± 0.61 μg ml-1). The PDDS-coated metal oxide nanoparticles showed superior antiplasmodial activity than the non-PDDS-coated metal oxide nanoparticles. Statistical analysis reveals that, significant in vitro antiplasmodial activity ( P < 0.05) was observed between the concentrations and time of exposure. The chemical injury to erythrocytes showed no morphological changes in erythrocytes by the nanoparticles after 48 h of incubation. It is concluded from the present study that, the PDDS-Fe3O4 showed good antiplasmodial activity and it might be used for the development of antiplasmodial drugs.

  1. Ultrasound influence on the activation step before electroless coating.

    Touyeras, F; Hihn, J Y; Delalande, S; Viennet, R; Doche, M L

    2003-10-01

    This paper is devoted to the electroless plating of non-conductive substrates under ultrasound at 530 kHz. The ultrasonic irradiation is applied to the activation and to the plating steps. Effects are measured by following the final copper thickness obtained in 1 h of plating time, easily correlated to the average plating rate. It appears that ultrasound has a strong influence on the plating rates enhancement, and assumptions can be made that this increase could be linked to the catalyst cleaning. This is confirmed by XPS measurements. PMID:12927613

  2. A Comparative Study of the Anti-Fungal Activity of Zinc Oxide and Titanium Dioxide Nano and Bulk Particles with Anti-Fungals against Fungi Isolated from Infected Skin and Dandruff Flakes

    Sara A George; M Shailaja Raj; Diana Solomon; Roselin P

    2014-01-01

    The anti-fungal activity of Zinc oxide and Titanium dioxide nano-particles was assessed by treating eight fungal cultures - Aspergillus niger, Trichophyton, Fonsecaea, Aspergillus flavus, Rhizopus oryzae, Fusarium, Ramichloridium schulzeri and Cladosporium, isolated from infected skin and dandruff flakes with the nanoparticles and analysing the extent of growth inhibition on agar and in broth media. The anti-fungal activity of these nano-particles was also compared to that of their respective...

  3. The behavior of active bactericidal and antifungal coating under visible light irradiation

    Xiao, Gang; Zhang, Xiaodong; Zhao, Yan; Su, Haijia, E-mail: suhj@mail.buct.edu.cn; Tan, Tianwei

    2014-02-15

    In the present paper, the novel active bactericidal and antifungal coatings (ABAC) have been prepared through the immobilization of Fe-doped TiO{sub 2} (anatase) with chitosan. The characterization of ABAC using optical microscope imaging, SEM, AFM and FTIR shows that the Fe doped TiO{sub 2} is embedded into the chitosan coating with favorable dispersion through the hydrogen bonds interaction between chitosan molecules and TiO{sub 2}. The contact angle measurement demonstrated the hydrophilicity of ABAC (θ = 34.5 ± 4.1°). The bactericidal activity of ABAC has been evaluated by inactivating three different test strains: Escherichia coli, Candida albicans and Aspergillus niger which illustrates the apparently higher bactericidal ability than chitosan, Fe-TiO{sub 2} and chitosan/TiO{sub 2} (pure) under visible light irradiation and its bactericidal activity is lasting for at least 24 h. ABAC showed rapid and efficient antibacterial ability for the three tested strains and its antibacterial ratio in 2 h for E. coli, C. albicans and A. niger was 99.9%, 97.0% and 95.0%, respectively. The prepared chitosan/TiO{sub 2} composite emulsion shows favorable storage stability and can be stored up to 1 year without losing its bactericidal activity. ABAC is a low-cost and eco-friendly antibacterial coating products and promising for domestic, medical and industrial applications.

  4. The behavior of active bactericidal and antifungal coating under visible light irradiation

    In the present paper, the novel active bactericidal and antifungal coatings (ABAC) have been prepared through the immobilization of Fe-doped TiO2 (anatase) with chitosan. The characterization of ABAC using optical microscope imaging, SEM, AFM and FTIR shows that the Fe doped TiO2 is embedded into the chitosan coating with favorable dispersion through the hydrogen bonds interaction between chitosan molecules and TiO2. The contact angle measurement demonstrated the hydrophilicity of ABAC (θ = 34.5 ± 4.1°). The bactericidal activity of ABAC has been evaluated by inactivating three different test strains: Escherichia coli, Candida albicans and Aspergillus niger which illustrates the apparently higher bactericidal ability than chitosan, Fe-TiO2 and chitosan/TiO2 (pure) under visible light irradiation and its bactericidal activity is lasting for at least 24 h. ABAC showed rapid and efficient antibacterial ability for the three tested strains and its antibacterial ratio in 2 h for E. coli, C. albicans and A. niger was 99.9%, 97.0% and 95.0%, respectively. The prepared chitosan/TiO2 composite emulsion shows favorable storage stability and can be stored up to 1 year without losing its bactericidal activity. ABAC is a low-cost and eco-friendly antibacterial coating products and promising for domestic, medical and industrial applications.

  5. Solvent-free synthesis, coating and morphogenesis of conductive polymer materials through spontaneous generation of activated monomers.

    Muramatsu, Ryo; Oaki, Yuya; Kuwabara, Kento; Hayashi, Kosei; Imai, Hiroaki

    2014-10-14

    Synthesis, coating, and morphogenesis of conductive polymers were achieved on a variety of substrates through spontaneous generation of activated monomer vapors under ambient pressure and low temperature conditions. The present approach facilitates the generation of complex hierarchical morphologies and the conductive coating for improvement of electrochemical properties. PMID:25145680

  6. Edible Active Coatings Based on Pectin, Pullulan, and Chitosan Increase Quality and Shelf Life of Strawberries (Fragaria ananassa).

    Treviño-Garza, Mayra Z; García, Santos; del Socorro Flores-González, Ma; Arévalo-Niño, Katiushka

    2015-08-01

    Edible active coatings (EACs) based on pectin, pullulan, and chitosan incorporated with sodium benzoate and potassium sorbate were employed to improve the quality and shelf life of strawberries. Fruits were washed, disinfected, coated by dipping, packed, and stored at 4 °C for 15 d. Application of EACs reduced (P 0.05) throughout storage, and ascorbic acid content was maintained in pectin-EAC coated strawberries. Microbiological analyses showed that application of EACs reduced (P coated strawberries presented the best results in microbial growth assays. Sensory quality (color, flavor, texture, and acceptance) improved and decay rate decreased (P coated strawberries. In conclusion, EACs based on polysaccharides improved the physicochemical, microbiological, and sensory characteristics, increasing the shelf life of strawberries from 6 (control) to 15 d (coated fruits). PMID:26189365

  7. Echicetin coated polystyrene beads: a novel tool to investigate GPIb-specific platelet activation and aggregation.

    Alexey Navdaev

    Full Text Available von Willebrand factor/ristocetin (vWF/R induces GPIb-dependent platelet agglutination and activation of αIIbβ3 integrin, which also binds vWF. These conditions make it difficult to investigate GPIb-specific signaling pathways in washed platelets. Here, we investigated the specific mechanisms of GPIb signaling using echicetin-coated polystyrene beads, which specifically activate GPIb. We compared platelet activation induced by echicetin beads to vWF/R. Human platelets were stimulated with polystyrene beads coated with increasing amounts of echicetin and platelet activation by echicetin beads was then investigated to reveal GPIb specific signaling. Echicetin beads induced αIIbβ3-dependent aggregation of washed platelets, while under the same conditions vWF/R treatment led only to αIIbβ3-independent platelet agglutination. The average distance between the echicetin molecules on the polystyrene beads must be less than 7 nm for full platelet activation, while the total amount of echicetin used for activation is not critical. Echicetin beads induced strong phosphorylation of several proteins including p38, ERK and PKB. Synergistic signaling via P2Y12 and thromboxane receptor through secreted ADP and TxA2, respectively, were important for echicetin bead triggered platelet activation. Activation of PKG by the NO/sGC/cGMP pathway inhibited echicetin bead-induced platelet aggregation. Echicetin-coated beads are powerful and reliable tools to study signaling in human platelets activated solely via GPIb and GPIb-triggered pathways.

  8. Removal of inclusions from molten aluminum with actively coated ceramic filters

    周鸣; 倪红军; 疏达; 张为玉; 李克; 孙宝德; 王俊

    2003-01-01

    Molten aluminum (A001) was filtered by using ceramic foam filters coated with active enamel. Tensile test shows that the elongation of filtered sample is increased by 15.5%, but the tensile strength of the sample is almost the same as that of unfiltered one. The fracture cracks and dimples of filtered sample are fine and homogeneous according to SEM examination. In addition, metallographic observation shows that the filtered sample has very few inclusions of approximately 8 μm in diameter, but the unfiltered sample has some inclusions of approximately 60 μm in length and 20 μm in width. However, it is suggested that the active enamel coat can effectively capture the inclusions and dissolve them during filtering molten aluminum.

  9. Chemical, biochemical, and microbiological aspects of chitosan quaternary salt as active coating on sliced apples

    Douglas de Britto

    2012-09-01

    Full Text Available The biocompatibility of chitosan and chitosan quaternary salt coatings was evaluated for use as edible coatings for sliced apple. Measurement of water loss, color change, and fungal growth appearance were monitored as a function of time. A significant brownish effect was observed on chitosan coated slices, varying greatly from L* = 76.5 and Hue angle = 95.9° (t = 0 to L* = 45.3 and Hue angle = 69.8° (t = 3 days, whilst for TMC coated samples the variation was considerable lower (L* = 74.1; Hue angle = 95.0° to (L* = 67.0; Hue angle = 83.8° within the same period. The hydrosoluble derivative N,N,N-trimethylchitosan demonstrated good antifungal activity against P. expansum although highly dependent on the polymer properties such as degree of quaternization. The most efficient formulation was that prepared from derivative having a degree of quaternization of 45%, high solubility, and high viscosity. This formulation restrained fungus spreading up to 30%, while for the control it reached almost 80% of the total assessed surfaces during 7 days of storage.

  10. Polydopamine-Coated Manganese Complex/Graphene Nanocomposite for Enhanced Electrocatalytic Activity Towards Oxygen Reduction.

    Parnell, Charlette M; Chhetri, Bijay; Brandt, Andrew; Watanabe, Fumiya; Nima, Zeid A; Mudalige, Thilak K; Biris, Alexandru S; Ghosh, Anindya

    2016-01-01

    Platinum electrodes are commonly used electrocatalysts for oxygen reduction reactions (ORR) in fuel cells. However, this material is not economical due to its high cost and scarcity. We prepared an Mn(III) catalyst supported on graphene and further coated with polydopamine, resulting in superior ORR activity compared to the uncoated PDA structures. During ORR, a peak potential at 0.433 V was recorded, which is a significant shift compared to the uncoated material's -0.303 V (both versus SHE). All the materials reduced oxygen in a wide pH range via a four-electron pathway. Rotating disk electrode and rotating ring disk electrode studies of the polydopamine-coated material revealed ORR occurring via 4.14 and 4.00 electrons, respectively. A rate constant of 6.33 × 10(6) mol(-1)s(-1) was observed for the polydopamine-coated material-over 4.5 times greater than the uncoated nanocomposite and superior to those reported for similar carbon-supported metal catalysts. Simply integrating an inexpensive bioinspired polymer coating onto the Mn-graphene nanocomposite increased ORR performance significantly, with a peak potential shift of over +730 mV. This indicates that the material can reduce oxygen at a higher rate but with lower energy usage, revealing its excellent potential as an ORR electrocatalyst in fuel cells. PMID:27528439

  11. In vivo biocompatibility of a plasma-activated, coronary stent coating.

    Waterhouse, Anna; Wise, Steven G; Yin, Yongbai; Wu, Buchu; James, Barbara; Zreiqat, Hala; McKenzie, David R; Bao, Shisan; Weiss, Anthony S; Ng, Martin K C; Bilek, Marcela M M

    2012-11-01

    Bare metal and drug-eluting coronary stents suffer an inherent lack of vascular cell and blood compatibility resulting in adverse patient responses. We have developed a plasma-activated coating (PAC) for metallic coronary stents that is durable, withstands crimping and expansion, has low thrombogenicity and can covalently bind proteins, linker-free. This has been shown to enhance endothelial cell interactions in vitro and has the potential to promote biointegration of stents. Using the rabbit denuded iliac artery model, we show for the first time that PAC is a feasible coating for coronary stents in vivo. The coating integrity of PAC was maintained following implantation and expansion. The rate of endothelialization, strut coverage, neointimal response and the initial immune response were equivalent to bare metal stents. Furthermore, the initial thrombogenicity caused by the PAC stents showed a reduced trend compared to bare metal stents. This work demonstrates a robust, durable, non-cytotoxic plasma-based coating technology that has the ability to covalently immobilize bioactive molecules for surface modification of coronary stents. Improvements in the clinical performance of implantable cardiovascular devices could be achieved by the immobilization of proteins or peptides that trigger desirable cellular responses. PMID:22889486

  12. Comparing graphene, carbon nanotubes, and superfine powdered activated carbon as adsorptive coating materials for microfiltration membranes.

    Ellerie, Jaclyn R; Apul, Onur G; Karanfil, Tanju; Ladner, David A

    2013-10-15

    Multi-walled carbon nanotubes (MWCNTs), nano-graphene platelets (NGPs), and superfine powdered activated carbon (S-PAC) were comparatively evaluated for their applicability as adsorptive coatings on microfiltration membranes. The objective was to determine which materials were capable of contaminant removal while causing minimal flux reduction. Methylene blue and atrazine were the model contaminants. When applied as membrane coatings, MWCNTs had minimal retention capabilities for the model contaminants, and S-PAC had the fastest removal. The membrane coating approach was also compared with a stirred vessel configuration, in which the adsorbent was added to a stirred flask preceding the membrane cell. Direct application of the adsorbent to the membrane constituted a greater initial reduction in permeate concentrations of the model contaminants than with the stirred flask setup. All adsorbents except S-PAC showed flux reductions less than 5% after application as thin-layer membrane coatings, and flux recovery after membrane backwashing was greater than 90% for all materials and masses tested. PMID:23911830

  13. Theoretical and experimental study of the photocatalytic activity of ZnO coated tubular reactor

    Highlights: • High quality ZnO thin films were deposited on the internal surface of fused silica tubing. • Surface carrier concentration was calculated theoretically under external irradiation. • Influence of film thickness on photocatalytic activity was explained by this model. • An optimum thickness around 60–70 nm was determined to get highest activity. -- Abstract: ZnO thin films were deposited inside of fused silica tubing by aerosol assisted chemical vapor deposition technique. The films were transparent, uniform, highly adherent and non-light scattering. Photocatalytic activity of internally ZnO coated tubing was evaluated by discoloration of a methyl orange aqueous solution in a batch reactor. Tubing was externally irradiated with UV-A at room temperature. A one dimensional model was proposed to calculate the spatial distribution of the carrier density and the films’ surface charge carrier concentration. This model can explain the influence of the films thickness on the photocatalytic activity. Results showed that the photocatalytic activity largely depends on the film thickness. For external irradiation of the films the optimum thickness was around 60–70 nm, for which the photocatalytic activity was maximum. The photonic efficiency of internally ZnO coated tubular reactors was evaluated as a function of initial colorant concentration, irradiation time and intensity. Furthermore, due to the high activity of the ZnO films, the films were repeatedly exposed to UV-A irradiation cycles, followed by activity measurement

  14. Antimicrobial Activity of TiO2 Nanoparticle-Coated Film for Potential Food Packaging Applications

    Siti Hajar Othman

    2014-01-01

    Full Text Available Recent uses of titanium dioxide (TiO2 have involved various applications which include the food industry. This study aims to develop TiO2 nanoparticle-coated film for potential food packaging applications due to the photocatalytic antimicrobial property of TiO2. The TiO2 nanoparticles with varying concentrations (0–0.11 g/ 100 mL organic solvent were coated on food packaging film, particularly low density polyethylene (LDPE film. The antimicrobial activity of the films was investigated by their capability to inactivate Escherichia coli (E. coli in an actual food packaging application test under various conditions, including types of light (fluorescent and ultraviolet (UV and the length of time the film was exposed to light (one–three days. The antimicrobial activity of the TiO2 nanoparticle-coated films exposed under both types of lighting was found to increase with an increase in the TiO2 nanoparticle concentration and the light exposure time. It was also found that the antimicrobial activity of the films exposed under UV light was higher than that under fluorescent light. The developed film has the potential to be used as a food packaging film that can extend the shelf life, maintain the quality, and assure the safety of food.

  15. Outdoor corrosion of zinc coated carbon steel, determined by thin layer activation

    Thin Layer Activation was applied in the frame of a European programme addressed to the evaluation of the corrosion the behaviour of different steels. This included outdoor exposure of zinc coated carbon steel in a rural-marine climatic environment, for a period of several months. The zinc layer of specimens was 10 micrometers thick. For the TLA studies 65Zn radio nuclides were produced along the full depth of the coating, by a cyclotron accelerated deuteron beam. For quantification of the material release, activity versus depth was determined using different thickness of Zn coatings on top the carbon steel. After exposure corrosion product were removed from the surface using a pickling solution and the residual activity was determined by gamma spectrometry. The high sensitivity of the method allowed the evaluation of relatively small thickness losses (i.e. 1.2 micrometer). Thickness loss results, obtained by the TLA method, were compared with those arising from the Atomic Absorption analysis of zinc detected in the pickling solutions. A good agreement was observed between the different methods

  16. Evaluation of Effect of a New Natural Radioprotectors in Nano Particles Form From Zinc Coumarate and Zinc Caffeiate on Rats Exposed to Gamma Rays

    Natural Radioprotectors as para -coumaric acids and caffeic acids are natural compounds in nano form zinc coumarate nano particles (Zn Coum.NPs) and zinc caffeiate nano particles (Zn Caf.NPs) have been shown to confer various biological effects, anticancer, enhance immune system and antioxidant properties. The present study was undertaken to evaluate the radio protective and possess ability of Zn Coum.NPs and Zn Caf.NPs against whole body -irradiation with a dose of 3 Gy, 4 times, every week up to 12 Gy. Zn Coum.NPs and Zn Caf.NPs were given to rats by intraperitoneal injection at a concentration of 5 mg/kg and 15 mg/kg body weight respectively, for 7 successive days, post irradiation for (Zn Coum.NPs + Zn Caf.NPs) and [(Zn Coum.NPs + Zn Caf.NPs) + Irradiated] groups and for 30 successive days for (Zn Coum.NPs + Zn Caf.NPs), [(Zn Coum.NPs + Zn Caf.NPs) + Irradiated] and [Irradiated + (Zn Coum.NPs + Zn Caf.NPs)] groups. The results indicated that gamma- irradiated group caused a significant decrease of body weight, antioxidants levels and (ThCD4 and TcCD8), and disorder in morphological, hematological, lipid profile and cell cycle as well as liver and kidney dysfunction, and increased in lipid peroxidation, nitric oxide, free radicals and DNA fragment, and histological changes in the hepatic tissues as vacuoles degeneration and necrosis of a great number of hepatocytes together with several hemorrhage and interstitial oedema. Whilst, the treatment with Zn Coum.NPs + Zn Caf.NPs pre or post-exposure to gamma-ray protected cellular system from harmful effects of gamma-radiation. The results clearly indicated that Zn Coum.NPs and Zn Caf.NPs possess protective effect to protect bimolecules from radiation induced damage and ability to scavenge free radicals might be playing an important role in its radio protective manifestation especially in cancer treatment with radiotherapy

  17. Bovine Serum Albumin and Chitosan Coated Silver Nanoparticles and Its Antimicrobial Activity against Oral and Nonoral Bacteria

    León Francisco Espinosa-Cristóbal

    2015-01-01

    Full Text Available Antimicrobial agents have been developed for drug-resistance infections, which have been rapidly increasing; however, the control of involved microorganisms is still a challenge. In this work, SNP with bovine serum albumin (BSA and chitosan (CS coatings were prepared with an aqueous reduction method, characterized using dispersion light scattering, transmission electron microscopy, and thermal analysis. Antibacterial activity was tested on seven oral and nonoral bacteria by microdilution test and scanning electron microscopy. Six different sizes and shapes of coated SNP were prepared and used. Characterization revealed narrow size and good distribution of particles, spherical and pseudospherical shapes, and the presence of coatings on the SNP surfaces. All samples showed antimicrobial activity, although smaller sizes and CS samples had the best inhibition effects. The highest microbial resistance was shown by Gram-positive bacteria. Although coated SNP action depends on particular bacterium, BSA and CS coated SNP could be used for drug-resistance infections.

  18. THE SIZE AND SURFACE COATING OF NANOSILVER DIFFERENTIALLY AFFECTS BIOLOGICAL ACTIVITY IN BLOOD BRAIN BARRIER (RBEC4) CELLS.

    Linking the physical properties of nanoparticles with differences in their biological activity is critical for understanding their potential toxicity and mode of action. The influence of aggregate size, surface coating, and surface charge on nanosilver's (nanoAg) movement through...

  19. Evaluation of Photocatalytic Active Coatings on Sintered Glass Tubes by Methylene Blue

    Colin Awungacha Lekelefac

    2013-01-01

    Full Text Available A comparative study between ten different photocatalytic active coatings was done. The effectiveness and photocatalytic activity of the coatings were studied by degradation experiments of methylene blue (MB dye under UV light illumination. The reactor design consisting of sintered glass packed in a borosilicate tube placed between two planar dielectric barrier discharge lamps (Osram Planon is reported for the first time. The coatings consisted of either titania, silica, or zinc on sintered borosilicate glass. The advantage of sol-gel in catalyst preparation was exploited to combine catalyst to act as cocatalyst. TiO2-P25 widely applied in suspension systems was effectively immobilized on sintered glass support with the aid of tetraethylorthosilicate (TEOS solution which acted as support material. Results indicated that TiO2-P25+SiO2, TiO2-P25+SiO2+Pt, and TiOSO4_30,6wt% films showed highest degradation rates close to 100% after 90 min illumination with degradation rates exceeding 50% after 30 minutes. TTIP+Pt showed lowest degradation rate.

  20. Zwitterionic Cellulose Carbamate with Regioselective Substitution Pattern: A Coating Material Possessing Antimicrobial Activity.

    Elschner, Thomas; Lüdecke, Claudia; Kalden, Diana; Roth, Martin; Löffler, Bettina; Jandt, Klaus D; Heinze, Thomas

    2016-04-01

    A polyzwitterion is synthesized by regioselective functionalization of cellulose possessing a uniform charge distribution. The positively charged ammonium group is present at position 6, while the negative charge of carboxylate is located at positions 2 and 3 of the repeating unit. The molecular structure of the biopolymer derivative is proved by NMR spectroscopy. This cellulose-based zwitterion is applied to several support materials by spin-coating and characterized by means of atomic force microscope, contact angle measurements, ellipsometry, and X-ray photoelectron spectroscopy. The coatings possess antimicrobial activity depending on the support materials (glass, titanium, tissue culture poly(styrene)) as revealed by confocal laser scanning microscopy and live/dead staining. PMID:26632022

  1. A Disposable Organophosphorus Pesticides Enzyme Biosensor Based on Magnetic Composite Nano-Particles Modified Screen Printed Carbon Electrode

    Weigang Wen

    2010-01-01

    Full Text Available A disposable organophosphorus pesticides (OPs enzyme biosensor based on magnetic composite nanoparticle-modified screen printed carbon electrodes (SPCE has been developed. Firstly, an acetylcholinesterase (AChE-coated Fe3O4/Au (GMP magnetic nanoparticulate (GMP-AChE was synthesized. Then, GMP-AChE was absorbed on the surface of a SPCE modified by carbon nanotubes (CNTs/nano-ZrO2/prussian blue (PB/Nafion (Nf composite membrane by an external magnetic field. Thus, the biosensor (SPCE|CNTs/ZrO2/PB/Nf|GMP-AChE for OPs was fabricated. The surface of the biosensor was characterized by scanning electron micrography (SEM and X-ray fluorescence spectrometery (XRFS and its electrochemical properties were studied by cyclic voltammetry (CV and differential pulse voltammetry (DPV. The degree of inhibition (A% of the AChE by OPs was determined by measuring the reduction current of the PB generated by the AChE-catalyzed hydrolysis of acetylthiocholine (ATCh. In pH = 7.5 KNO3 solution, the A was related linearly to the concentration of dimethoate in the range from 1.0 × 10-3–10 ng•mL-1 with a detection limit of 5.6 × 10-4 ng•mL-1. The recovery rates in Chinese cabbage exhibited a range of 88%–105%. The results were consistent with the standard gas chromatography (GC method. Compared with other enzyme biosensors the proposed biosensor exhibited high sensitivity, good selectivity with disposable, low consumption of sample. In particular its surface can be easily renewed by removal of the magnet. The convenient, fast and sensitive voltammetric measurement opens new opportunities for OPs analysis.

  2. Ultrasound-mediated method for rapid delivery of nano-particles into cells for intracellular surface-enhanced Raman spectroscopy and cancer cell screening

    Surface-enhanced Raman spectroscopy (SERS) is a powerful technology for providing finger-printing information of cells. A big challenge has been the long time duration and inefficient uptake of metal nano-particles into living cells as substrate for SERS analysis. Herein, a simple method (based on ultrasound) for the rapid transfer of silver nanoparticles (NPs) into living cells for intracellular SERS spectroscopy was presented. In this study, the ultrasound-mediated method for NP delivery overcame the shortcoming of ‘passive uptake’, and achieved quick acquisition of reproducible SERS spectra from living human nasopharyngeal carcinoma cell lines (C666 and CNE1) and normal nasopharyngeal cell line (NP69). Tentative assignment of the Raman bands in the measured SERS spectra showed cancer cell specific biomolecular differences, including significantly lower DNA concentrations and higher protein concentrations in cancerous nasopharyngeal cells as compared to those of normal cells. Combined with PCA–LDA multivariate analysis, ultrasound-mediated cell SERS spectroscopy differentiated the cancerous cells from the normal nasopharyngeal cells with high diagnostic accuracy (98.7%), demonstrating great potential for high-throughput cancer cell screening applications. (paper)

  3. Elaboration by ion implantation of cobalt nano-particles in silica layers and modifications of their properties by electron and swift heavy ion irradiations

    This work aims to investigate the capability of ion irradiations to elaborate magnetic nano-particles in silica layers, and to modify their properties. Co+ ions have been implanted at 160 keV at fluences of 2.1016, 5.1016 and 1017 at/cm2, and at temperatures of 77, 295 and 873 K. The dependence of the particle size on the implantation fluence, and more significantly on the implantation temperature has been shown. TEM (transmission electronic microscopy) observations have shown a mean diameter varying from 1 nm for implantations at 2.1016 Co+/cm2 at 77 K, to 9.7 nm at 1017 Co+/cm2 at 873 K. For high temperature implantations, two regions of particles appear. Simulations based on a kinetic 3-dimensional lattice Monte Carlo method reproduce quantitatively the features observed for implantations. Thermal treatments induce the ripening of the particles. Electron irradiations at 873 K induce an important increase in mean particle sizes. Swift heavy ion irradiations also induce the ripening of the particles for low fluences, and an elongation of the particles in the incident beam direction for high fluences, resulting in a magnetic anisotropy. Mechanisms invoked in thermal spike model could also explain this anisotropic growth. (author)

  4. CT-guided aspiration cytology of advanced silicosis and confirmation of the deposited zeolite nano particles through X ray diffraction: A novel approach.

    Bandyopadhyay, Arghya; Majumdar, Kaushik; Chakraborty, Abhijit; Mitra, Partha; Nag, Subhomoy

    2016-03-01

    Silicosis is a common occupational lung disease, resulting in fibrotic nodular lesions in the upper lobes of the lung parenchyma. Most of the pneumoconioses are diagnosed on the basis of relevant history and clinico-radiological correlation. Image-guided aspiration cytology appears to be poorly yielding and is not usually considered as a diagnostic modality. However, silicosis may sometimes offer a diagnostic challenge because of its radiological resemblance and clinical overlap with pulmonary tuberculosis and neoplastic lesions. We present a unique situation where image-guided fine needle aspiration cytology (FNAC) has been advised on the basis of nodular upper lobe opacities. The cytology smears revealed hypocellular granular material, while phase contrast and polarized light microscopy highlighted crystalline particles. History of silica dust exposure long back was available after the cytological evaluation, suggesting the diagnosis of pulmonary silicosis. X ray diffraction (XRD) crystallography was also possible on cytology smears, confirming zeolite nano particles of size as small as 40 - 50 nm as the concerned agent for the first time. Cytological evaluation by phase contrast and polarized light microscopy may be useful for the confirmation of silicosis, supplemented by clinical history and radiological evaluation. XRD on smears may help in determination of chemical nature and particle size. Diagn. Cytopathol. 2016;44:246-249. © 2015 Wiley Periodicals, Inc. PMID:26748653

  5. Trends in anomalous small-angle X-ray scattering in grazing incidence for supported nano-alloyed and core-shell metallic nano-particles

    As atomic structure and morphology of particles are directly correlated to their functional properties, experimental methods probing local and average features of particles at the nano-scale elicit a growing interest. Anomalous small-angle X-ray scattering (ASAXS) is a very attractive technique to investigate the size, shape and spatial distribution of nano-objects embedded in a homogeneous matrix or in porous media. The anomalous variation of the scattering factor close to an absorption edge enables element specific investigations. In the case of supported nano-objects, the use of grazing incidence is necessary to limit the probed depth. The combination of grazing incidence with the anomalous technique provides a powerful new method, anomalous grazing incidence small-angle X-ray scattering (AGISAXS), to disentangle complex chemical patterns in supported multi-component nano-structures. Nevertheless, a proper data analysis requires accurate quantitative measurements associated to an adapted theoretical framework. This paper presents anomalous methods applied to nano-alloys phase separation in the 1-10 nm size range, and focuses on the application of AGISAXS in bimetallic systems: nano-composite films and core-shell supported nano-particles

  6. Magnetic and structural properties of RE doped Co-ferrite (REåNd, Eu, and Gd) nano-particles synthesized by co-precipitation

    Cobalt ferrite nano-particles, Co0.9RE0.1Fe2O4, with three different rare earth ions (Nd, Eu, and Gd) were prepared by the chemical co-precipitation method. X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), Fourier Transform Infrared (FTIR), and Vibrating Sample Magnetometry were carried out to study the structural and magnetic properties, respectively. The XRD results revealed that the crystal size is about 22 nm for Gd–Co ferrite, which is close to the particle sizes observed from TEM images (20 nm). The FTIR measurements between 350 and 4000 cm−1 confirmed the intrinsic cation vibrations of the spinel structure. The results showed that the RE ions increase both vibrational frequencies and bond strength. The magnetic results showed that the highest magnetic coercivity and the loop area correspond to the Gd–Co ferrite, making it suitable for hyperthermia treatment. Also, the Curie point was decreased by the RE ions and had its lowest value for Nd–Co ferrite (336 °C). - Highlights: • Magnetic and structural studies of RE3+–Co-ferrite (RE=Nd, Gd, and Eu) are investigated. • Simple co-precipitation method involving less energy and low-cost is used. • Nanoparticles with high coercivity, magnetization and loop area are obtained. • The obtained particles are used in nanomedicine applications like hyperthermia

  7. Removal of methyl orange from aqueous solution by Azolla filicoloides: Synthesis of Fe3O4 nano-particles and its surface modification by the extracted pectin of Azolla

    Roohan Rakhshaee; Masoud Giahi; Afshin Pourahmad

    2011-01-01

    The modified Fe3O4 nano-particles with the extracted pectin from the cell wall of Azolla filicoloides (FN-EP) can remove methyl orange as a water-soluble azo dye from waste water better than Azolla and the extracted pectin from Azolla (EPA), alone. It could be due to more crowding the main functional groups of uptake after binding pectin with nano-particles. Thermodynamic studies showed that adsorption equilibrium constant (KL) and maximum adsorption capacities (Qmax) were increased with decreasing temperature (exothermic). The maximum uptake capacity (Qmax) of dye by FN-EP in a batch reactor was 0.533, 0.498 and 0.446 mmol/g at 5, 25 and 50 ℃, respectively. The enthalpy change (AH) and entropy change (△S) were -15.31 kJ/mol and -0.02434 kJ/mol K, respectively.

  8. Solution plasma synthesis of Au nanoparticles for coating titanium dioxide to enhance its photocatalytic activity

    Nakasugi, Yuki; Saito, Genki [Center for Advanced Research of Energy and Materials, Hokkaido University, Sapporo 060-8628 (Japan); Yamashita, Toru [Faculty of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Sakaguchi, Norihito [Center for Advanced Research of Energy and Materials, Hokkaido University, Sapporo 060-8628 (Japan); Akiyama, Tomohiro, E-mail: takiyama@eng.hokudai.ac.jp [Center for Advanced Research of Energy and Materials, Hokkaido University, Sapporo 060-8628 (Japan)

    2015-05-29

    A convenient method for coating titanium dioxide (TiO{sub 2}) by Au nanoparticles (AuNPs) is demonstrated in solution plasma to improve the photocatalytic activity of TiO{sub 2}. AuNPs from a metallic Au electrode were bonded to the surface of a commercial TiO{sub 2} powder, which acted as a catalyst support, with the reaction taking place in an electrolyte solution. The effect of diverse plasma conditions on the size and productivity of the AuNPs was investigated initially to provide a reference in the absence of TiO{sub 2}. At 290 V, “partial plasma” was attained, with only a weak light emission surrounding the Au electrode. Conditions then evolved to “full plasma”, with a strong orange emission at 330 V. Partial or full status was maintained for 1 h at 300 and 400 V, respectively. At the transition to full, the AuNP particle size increased from 3.72 to 6.09 nm and the productivity increased dramatically from 0.025 to 0.87 mg h{sup −1} mm{sup −2}. Stronger plasma very efficiently synthesized AuNPs, and therefore, it was adopted for further study. AuNP-TiO{sub 2} combinations were formed by applying 400 V to a TiO{sub 2}-dispersed solution. In these experiments, TiO{sub 2} coated with AuNPs was synthesized; these combinations of AuNP-TiO{sub 2} had 0.44 mol% of Au. The photocatalytic activity of AuNP-TiO{sub 2} was investigated by measuring the degradation of Rhodamine B (RhB). Under UV irradiation, the AuNP-TiO{sub 2} particles removed up to 95% of the dye in 70 min. Commercial TiO{sub 2} achieves values closer to 85%. The results thus raise the possibility that solution plasma methods can be generalized as a means for achieving catalysis-enhancing coatings. - Highlights: • Au nanoparticles with a diameter of several nm were synthesized by solution plasma. • The effect of plasma conditions on the Au nanoparticles formation was investigated. • High resolution TEM was conducted to investigate the crystal structure. • Au nanoparticles were coated

  9. Silver release and antimicrobial properties of PMMA films doped with silver ions, nano-particles and complexes

    Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver–imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with L-cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli. It was found that PMMA films doped with Ag+ had greater activity than those doped with nanoparticles and silver–imidazole polymeric complexes. However, the antimicrobial efficiency of Ag+ doped films was only short-term. Contrary, the antimicrobial activity of silver–imidazole/PMMA films increased in time of sample soaking. - Highlights: • PMMA thin films doped with silver ions, nanoparticles (AgNPs) and silver–imidazole helical complexes (AgIm) were studied. • Silver release from doped polymer films and its biological activity were estimated. • Antimicrobial properties of doped polymer films were also studied. • Ag ions doped films showed the strongest antimicrobial activity, which quickly disappeared. • AgIm and AgNPs doped films showed more stable antimicrobial properties. • AgIm complexes conserve their structure after addition into polymer and after leaching

  10. Silver release and antimicrobial properties of PMMA films doped with silver ions, nano-particles and complexes

    Lyutakov, O., E-mail: lyutakoo@vscht.cz [Department of Solid State Engineering, Institute of Chemical Technology, Prague (Czech Republic); Goncharova, I. [Department of Analytical Chemistry, Institute of Chemical Technology, Prague (Czech Republic); Rimpelova, S. [Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague (Czech Republic); Kolarova, K.; Svanda, J.; Svorcik, V. [Department of Solid State Engineering, Institute of Chemical Technology, Prague (Czech Republic)

    2015-04-01

    Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver–imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with L-cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli. It was found that PMMA films doped with Ag{sup +} had greater activity than those doped with nanoparticles and silver–imidazole polymeric complexes. However, the antimicrobial efficiency of Ag{sup +} doped films was only short-term. Contrary, the antimicrobial activity of silver–imidazole/PMMA films increased in time of sample soaking. - Highlights: • PMMA thin films doped with silver ions, nanoparticles (AgNPs) and silver–imidazole helical complexes (AgIm) were studied. • Silver release from doped polymer films and its biological activity were estimated. • Antimicrobial properties of doped polymer films were also studied. • Ag ions doped films showed the strongest antimicrobial activity, which quickly disappeared. • AgIm and AgNPs doped films showed more stable antimicrobial properties. • AgIm complexes conserve their structure after addition into polymer and after leaching.

  11. Active and Secretory IgA-Coated Bacterial Fractions Elucidate Dysbiosis in Clostridium difficile Infection

    Moya, Andrés; Vázquez-Castellanos, Jorge F.; Artacho, Alejandro; Chen, Xinhua; Kelly, Ciaran

    2016-01-01

    ABSTRACT The onset of Clostridium difficile infection (CDI) has been associated with treatment with wide-spectrum antibiotics. Antibiotic treatment alters the activity of gut commensals and may result in modified patterns of immune responses to pathogens. To study these mechanisms during CDI, we separated bacteria with high cellular RNA content (the active bacteria) and their inactive counterparts by fluorescence-activated cell sorting (FACS) of the fecal bacterial suspension. The gut dysbiosis due to the antibiotic treatment may result in modification of immune recognition of intestinal bacteria. The immune recognition patterns were assessed by FACS of bacterial fractions either coated or not with intestinal secretory immunoglobulin A (SIgA). We described the taxonomic distributions of these four bacterial fractions (active versus inactive and SIgA coated versus non-SIgA coated) by massive 16S rRNA gene amplicon sequencing and quantified the proportion of C. difficile toxin genes in the samples. The overall gut microbiome composition was more robustly influenced by antibiotics than by the C. difficile toxins. Bayesian networks revealed that the C. difficile cluster was preferentially SIgA coated during CDI. In contrast, in the CDI-negative group Fusobacterium was the characteristic genus of the SIgA-opsonized fraction. Lactobacillales and Clostridium cluster IV were mostly inactive in CDI-positive patients. In conclusion, although the proportion of C. difficile in the gut is very low, it is able to initiate infection during the gut dysbiosis caused by environmental stress (antibiotic treatment) as a consequence of decreased activity of the protective bacteria. IMPORTANCE C. difficile is a major enteric pathogen with worldwide distribution. Its expansion is associated with broad-spectrum antibiotics which disturb the normal gut microbiome. In this study, the DNA sequencing of highly active bacteria and bacteria opsonized by intestinal secretory immunoglobulin

  12. Calcium phosphate/porous silicon biocomposites prepared by cyclic deposition methods: Spin coating vs electrochemical activation

    Hernandez-Montelongo, J., E-mail: jacobo.hernandez@uam.es [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Gallach, D.; Naveas, N.; Torres-Costa, V. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Climent-Font, A. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Centro de Microanálisis de Materiales (CMAM), Universidad Autónoma de Madrid, Madrid 28049 (Spain); García-Ruiz, J.P. [Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, Madrid 28049 (Spain); Manso-Silvan, M. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain)

    2014-01-01

    Porous silicon (PSi) provides an excellent platform for bioengineering applications due to its biocompatibility, biodegradability, and bioresorbability. However, to promote its application as bone engineering scaffold, deposition of calcium phosphate (CaP) ceramics in its hydroxyapatite (HAP) phase is in progress. In that sense, this work focuses on the synthesis of CaP/PSi composites by means of two different techniques for CaP deposition on PSi: Cyclic Spin Coating (CSC) and Cyclic Electrochemical Activation (CEA). Both techniques CSC and CEA consisted on alternate Ca and P deposition steps on PSi. Each technique produced specific morphologies and CaP phases using the same independent Ca and P stem-solutions at neutral pH and at room temperature. The brushite (BRU) phase was favored with the CSC technique and the hydroxyapatite (HAP) phase was better synthesized using the CEA technique. Analyses by elastic backscattering spectroscopy (EBS) on CaP/PSi structures synthesized by CEA supported that, by controlling the CEA parameters, an HAP coating with the required Ca/P atomic ratio of 1.67 can be promoted. Biocompatibility was evaluated by bone-derived progenitor cells, which grew onto CaP/PSi prepared by CSC technique with a long-shaped actin cytoskeleton. The density of adhered cells was higher on CaP/PSi prepared by CEA, where cells presented a normal morphological appearance and active mitosis. These results can be used for the design and optimization of CaP/PSi composites with enhanced biocompatibility for bone-tissue engineering. - Highlights: • Proposed cyclic methods produce specific morphologies and CaP phases in biocomposites. • The brushite phase is favored in the biocomposite produced by Cyclic Spin Coating. • The hydroxyapatite phase is favored in the biocomposite produced by Cyclic Electrochemical Activation. • The Ca/P atomic ratio of hydroxyapatite was validated by elastic backscattering spectroscopy. • Cells grown showed morphological and

  13. Calcium phosphate/porous silicon biocomposites prepared by cyclic deposition methods: Spin coating vs electrochemical activation

    Porous silicon (PSi) provides an excellent platform for bioengineering applications due to its biocompatibility, biodegradability, and bioresorbability. However, to promote its application as bone engineering scaffold, deposition of calcium phosphate (CaP) ceramics in its hydroxyapatite (HAP) phase is in progress. In that sense, this work focuses on the synthesis of CaP/PSi composites by means of two different techniques for CaP deposition on PSi: Cyclic Spin Coating (CSC) and Cyclic Electrochemical Activation (CEA). Both techniques CSC and CEA consisted on alternate Ca and P deposition steps on PSi. Each technique produced specific morphologies and CaP phases using the same independent Ca and P stem-solutions at neutral pH and at room temperature. The brushite (BRU) phase was favored with the CSC technique and the hydroxyapatite (HAP) phase was better synthesized using the CEA technique. Analyses by elastic backscattering spectroscopy (EBS) on CaP/PSi structures synthesized by CEA supported that, by controlling the CEA parameters, an HAP coating with the required Ca/P atomic ratio of 1.67 can be promoted. Biocompatibility was evaluated by bone-derived progenitor cells, which grew onto CaP/PSi prepared by CSC technique with a long-shaped actin cytoskeleton. The density of adhered cells was higher on CaP/PSi prepared by CEA, where cells presented a normal morphological appearance and active mitosis. These results can be used for the design and optimization of CaP/PSi composites with enhanced biocompatibility for bone-tissue engineering. - Highlights: • Proposed cyclic methods produce specific morphologies and CaP phases in biocomposites. • The brushite phase is favored in the biocomposite produced by Cyclic Spin Coating. • The hydroxyapatite phase is favored in the biocomposite produced by Cyclic Electrochemical Activation. • The Ca/P atomic ratio of hydroxyapatite was validated by elastic backscattering spectroscopy. • Cells grown showed morphological and

  14. Titania Supported Pt and Pt/Pd Nano-particle Catalysts for the Oxidation of Sulfur Dioxide

    Koutsopoulos, Sotiris; Johannessen, Tue; Eriksen, Kim Michael;

    2006-01-01

    Several types of titania (anatase) were used as supports for pure platinum and Pt–Pd bimetallic alloy catalysts. The preparation methods, normal wet impregnation technique and flame aerosol synthesis, obtained metal loadings of 2% by weight. The prepared catalysts were tested for SO2 oxidation...... activity at atmospheric pressure in the temperature range 250–600 °C. The SO2 to SO3 conversion efficiency of the Pt–Pd alloy was significantly higher than that of the individual metals. The effects of the preparation method and the titania type used on the properties and activity of the resulting catalyst...

  15. The n-MAO/EPD bio-ceramic composite coating fabricated on ZK60 magnesium alloy using combined micro-arc oxidation with electrophoretic deposition

    Highlights: • Adding CeO2/ZrO2 nano-particles to modify the properties of n-MAO coating. • A bio-ceramic n-MAO/EPD composite coating was prepared by two-step methods. • The n-MAO/EPD composite coating with HA has a favorable anti-corrosion effect. - Abstract: A bio-ceramic composite coating was fabricated on ZK60 magnesium (Mg) alloy using combined micro-arc oxidation (MAO) with electrophoretic deposition (EPD) technique. The MAO coating as the basal layer was produced in alkaline electrolyte with (n-MAO coating) and without (MAO coating) the addition of CeO2 and ZrO2 nano-particles, respectively. A hydroxyapatite (HA) coating as the covering layer was deposited on the n-MAO coating to improve the biological properties of the coating (n-MAO/EPD composite coating). The morphology and phase composition of three treated coatings were investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD). The corrosion resistance of these coatings was evaluated with potentiodynamic polarization tests and immersion tests in simulated body fluid (SBF) at 36.5 ± 0.5 °C. The XRD spectra showed that the CeO2 and ZrO2 peaks can be collected in the n-MAO coating, and HA particles exists in the n-MAO/EPD composite coating. The results of corrosion tests indicated that the n-MAO/EPD composite coating owned increased bioactivity and long-term protective ability compared with the MAO coating and the n-MAO coating. Thus Mg alloy coated with the n-MAO/EPD composite coating should be more suited as biodegradable bone implants

  16. The n-MAO/EPD bio-ceramic composite coating fabricated on ZK60 magnesium alloy using combined micro-arc oxidation with electrophoretic deposition

    Xiong, Ying, E-mail: yxiong@zjut.edu.cn [College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Lu, Chao [College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Wang, Chao; Song, Renguo [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China)

    2014-12-15

    Highlights: • Adding CeO{sub 2}/ZrO{sub 2} nano-particles to modify the properties of n-MAO coating. • A bio-ceramic n-MAO/EPD composite coating was prepared by two-step methods. • The n-MAO/EPD composite coating with HA has a favorable anti-corrosion effect. - Abstract: A bio-ceramic composite coating was fabricated on ZK60 magnesium (Mg) alloy using combined micro-arc oxidation (MAO) with electrophoretic deposition (EPD) technique. The MAO coating as the basal layer was produced in alkaline electrolyte with (n-MAO coating) and without (MAO coating) the addition of CeO{sub 2} and ZrO{sub 2} nano-particles, respectively. A hydroxyapatite (HA) coating as the covering layer was deposited on the n-MAO coating to improve the biological properties of the coating (n-MAO/EPD composite coating). The morphology and phase composition of three treated coatings were investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD). The corrosion resistance of these coatings was evaluated with potentiodynamic polarization tests and immersion tests in simulated body fluid (SBF) at 36.5 ± 0.5 °C. The XRD spectra showed that the CeO{sub 2} and ZrO{sub 2} peaks can be collected in the n-MAO coating, and HA particles exists in the n-MAO/EPD composite coating. The results of corrosion tests indicated that the n-MAO/EPD composite coating owned increased bioactivity and long-term protective ability compared with the MAO coating and the n-MAO coating. Thus Mg alloy coated with the n-MAO/EPD composite coating should be more suited as biodegradable bone implants.

  17. Multiwalled-carbon nanotubes and polyaniline coating on electro-active paper for bending actuator

    Yun, Sungryul; Kim, Jaehwan

    2006-06-01

    Multi-walled carbon nanotubes (MWNT) and polyaniline are coated on an electro-active paper (EAPap) to improve the performance of the bending actuator, and its performance is tested. EAPap actuators made with cellulose paper have merits in terms of large bending displacement, ultra-lightweight, dryness, low actuation voltage and power consumption, low cost and biodegradability. However, the force output of actuators is small and the actuation frequency is low. Thus, MWNT and emeraldine salt polyaniline (PANI) are coated on the EAPap material to improve the force and the actuation frequency. The MWNT and PANI solution is made by sonication, and the sonication time and the weight per cents of the MWNT and PANI are optimized to improve the hybrid actuator performance. The optimum condition is associated with conversion of the partial conductive state PANI into the emeraldine formed PANI by the chemical bonding between the MWNT and PANI. The performance improvement of the EAPap actuator coated with MWNT/PANI is investigated in terms of displacement, blocking force and efficiency. In the presence of an electric field (0.35 V µm-1) on the hybrid EAPap actuator, 250% of the output force, 160% of the resonance frequency and 50% of efficiency are improved.

  18. 复合膜中纳米银粒子的光吸收特性研究%The research on optical absorption properties of silver nano-particles in composite film

    李贵安

    2001-01-01

    本文通过溶胶凝胶法,制备出金属纳米银粒子复合膜.电镜(TEM)测量结果表明,复合膜中所掺入的银粒子尺寸属纳米量级.实验测出了复合膜中银粒子的吸收光谱,与其在银胶中吸收谱相比,发现其吸收峰红移52.5nm.并对测试结果进行了细致分析.%In the paper ,we reported composite film of silver nano-particles prepared via the Sol-Gel technique and its measurements of the optical absorption. The TEM photograph of composite film showed that silver particles size was nanoscale. The absorption peak of silver nano-particles in composite film yield red-shift as compared with silver nano-particles in colloidal solution. The results were analyzed and discussed in detail.

  19. The effect of the post-annealing temperature on the nano-structure and energy band gap of SnO2 semiconducting oxide nano-particles synthesized by polymerizing-complexing sol-gel method

    Nano-crystalline SnO2 particles have been synthesized by sol-gel process using a simple starting hydro-alcoholic solution consisting of SnCl4, 5H2O and citric acid as complexing and ethylene glycol as polymerization agents. The structural properties of the prepared tin oxide nano-powders annealed at different temperatures (300-700 deg. C) have been characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses. The XRD patterns show SnO2-cassiterite phase in the nano-powders, and size of crystals increases by increasing the annealing temperatures. The TEM images show nano-particles as clusters with size in the range of 5-25 nm. Electron diffraction pattern of nano-powders annealed at different temperatures shows a homogeneous distribution of spherical particles due to the effect of ethylene glycol as polymerizing agent in sol-gel process. The optical direct band gap values of SnO2 nano-particles were calculated to be about 4.05-4.11 eV in the temperature range 300-700 deg. C by optical absorption measurements. These values exibit nearly a 0.5 eV blue shift from that of bulk SnO2 (3.6 eV), which is related to size decrease of the particles and reaching to the quantum confinement limit of nano-particles

  20. Recycled ABS Resin Toughened and Reinforced by Elastomer/Inorganic Nano-Particle Composite System%弹性体/无机纳米粒子复合体系增强增韧回收ABS树脂

    孔雪松

    2013-01-01

    The toughening of elastomer and inorganic nano-particle to recycled ABS was studied respectively.The results show that elastomer restores the toughness of recycles ABS,but leads to decrease of rigidity,meanwhile inorganic nano-particle can increase the toughness partly,also leads to increases of rigidity.Finally recycled ABS is modified by elastomer/inorganic nano-particle composite system.When 5%~8% ABS rubber powder and 2% ~3% inorganic particle are added,the recycled ABS resin is toughened and reinforced.%分别研究了弹性体和无机纳米粒子对回收丙烯腈-丁二烯-苯乙烯共聚物(ABS)的增韧.结果表明:弹性体能使回收ABS树脂的韧性得到恢复,但导致刚性下降;无机纳米粒子对ABS树脂的增韧能力有限,但能增加ABS的刚性.最后采用弹性体/无机纳米粒子复合体系改性回收ABS树脂,添加质量分数5%~8%的高胶粉和质量分数2%~3%无机纳米粒子时,实现了对回收ABS树脂的增强增韧.

  1. Microstructures and properties of plasma sprayed FeAl/CeO2/ZrO2 nano-composite coating

    Commercial FeAl powders and ZrO2 nano-particles as well as CeO2 additive were reconstituted into a novel multi-compositional feedstock powders via spray drying. The resulting feedstock powders were used to deposit FeAl/CeO2/ZrO2 nano-composite coating by plasma spraying on 1Cr18Ni9Ti stainless steel. An X-ray diffractometer (XRD), a scanning electron microscope equipped with an energy dispersive spectrometer (SEM/EDS), and a field emission scanning electron microscope equipped with an energy dispersive spectrometer (FESEM/EDS) were employed to characterize the microstructure of the as-prepared feedstock powders and nano-composite coating. At the same time, the mechanical properties and friction and wear behavior of the nano-composite coating and pure FeAl coating were comparatively evaluated by using a Vickers microindentation tester and ball-on-disk sliding wear tribotester, respectively. And the wear mechanisms for the two types of coatings are discussed in terms of their microstructure and mechanical properties. Results indicate that the nano-composite coating has a much higher hardness and fracture toughness as well as drastically increased wear resistance than pure FeAl coating, which could be mainly attributed to the reinforcing effect of ZrO2 nano-particles and partially attributed to the refining effect of CeO2 in the nano-composite coating.

  2. Thick Graded Nanostructured Zirconia-NiCoCrAlY Composite Coatings by Plasma Spraying

    YANG Hui; WANG Han-gong

    2004-01-01

    Thick Nanostructured PSZ-NiCoCrAlY graded TBCs were got byair plasma spraying. The results reveal the morphology and phase transformation of TBCs by means of SEM and XRD. The plasma spray process results in a characteristic layered structure consisting of lamellae, unmelted nano-particles and an inter-lamellar porosity. The test results of thermal shock show that the graded coatings have different failure behavior. The failure mode was the spallation of top coat due to thermal stress. It has been found that the lamella consists of nanoscale columnar grains parallel to the spraying direction.

  3. SiO2-coatings on glass containing copper colloids using the sol-gel-technique

    Mennig, Martin; Schmitt, Mike; Kutsch, Bernd; Schmidt, Helmut K.

    1994-01-01

    A sol-gel method for the preparation of transparent copper nano particle-containing SiO2 coatings on glass has been developed. The sol is synthesised from alkoxysilanes and tetra ethyl orthosilicate with copper ammine complexes, prepared from Cu²+ salts and amino alkoxy silames. Glass substrates are coated by dipping and layers up to 1 µm in thickness are obtained after thermal densification at temperatures between 200°-500°C. The Cu colloid formation can be achieved using a reducing atmosphe...

  4. Structural characterization of electric-field assisted dip-coating of gold nanoparticles on silicon

    Ghada H. Dushaq; Amro Alkhatib; Mahmoud S. Rasras; Nayfeh, Ammar M.

    2015-01-01

    We report the effect of applying an electric field on the surface coverage of 40nm gold colloidal nanoparticles on silicon wafer using dip-coating and electrochemical cell set up. By applying electric field during the dip-coating of silicon wafer in a solution of gold nano particles (GNP) the surface coverage increased by 10% when the electric field varied from 5V/cm to 25V/cm at fixed deposition time of 90s. Ultra High Resolution Scanning Electron Microscopy (HRSEM) images shows that the par...

  5. Antimicrobial activity and cytocompatibility of silver nanoparticles coated catheters via a biomimetic surface functionalization strategy

    Wu K

    2015-12-01

    Full Text Available Ke Wu,1 Yun Yang,2,3 Yanmei Zhang,2,3 Jiexi Deng,1 Changjian Lin2,31Department of Cardiology, The Affiliated Dongnan Hospital of Xiamen University, Zhangzhou, 2Department of Medical Materials, Beijing Medical Implant Engineering Research Center, Beijing Naton Technology Group, Beijing, 3State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, People’s Republic of ChinaAbstract: Catheter-related bloodstream infections are a significant problem in the clinic and may result in a serious infection. Here, we developed a facile and green procedure for buildup of silver nanoparticles (AgNPs on the central venous catheters (CVCs surface. Inspired by mussel adhesive proteins, dopamine was used to form a thin polydopamine layer and induce AgNPs formation without additional reductants or stabilizers. The chemical and physicochemical properties of AgNPs coated CVCs were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and water contact angle. The Staphylococcus aureus culture experiment was used to study the antibacterial properties. The cytocompatibility was assessed by water soluble tetrazolium salts (WST-1 assay, fluorescence staining, and scanning electron microscopy analysis. The results indicated that the CVCs surface was successfully coated with compact AgNPs. AgNPs were significantly well separated and spherical with a size of 30–50 nm. The density of AgNPs could be modulated by the concentration of silver nitrate solution. The antibacterial activity was dependent on the AgNPs dose. The high dose of AgNPs showed excellent antibacterial activity while associated with increased cytotoxicity. The appropriate density of AgNPs coated CVCs could exhibit improved biocompatibility and maintained evident sterilization effect. It is promising to design mussel-inspired silver releasing CVCs with both

  6. Ammonia Synthesis using Ti and Nb Nitride Nano-particles Prepared by Mesoporous Graphitic C3N4

    Kumagai, Hiromu

    2015-01-22

    TiN and NbN nanoparticles were synthesized from mesoporous graphitic C3N4 (mpg-C3N4) as a reactive template and used as the catalyst for ammonia synthesis. The obtained TiN and NbN nanoparticles possess high surface areas of 299 and 275 m2 g-1, respectively, making them attractive in the use of catalysis and support. Although most of the TiN and NbN particles show no measurable activity for ammonia formation, the nanoparticles enabled an ammonia synthesis rate of 31 μmol h-1 g-cat-1 at 673 K and 0.1 MPa of synthesis gas (N2 + 3H2) for both TiN and NbN catalysts. It is evident that the formation of nanoparticles with high nitride surface area is essential for the materials to function as catalysts in ammonia synthesis. The addition of Fe to TiN enhanced the ammonia synthesis activity, whereas it had detrimental effects on the catalytic activity of NbN. The properties of these catalysts in ammonia synthesis are discussed.

  7. Electrodeposition and Corrosion Resistance Properties of Zn-Ni/TiO2 Nano composite Coatings

    B. M. Praveen

    2011-01-01

    Full Text Available Nano sized TiO2 particles were prepared by sol-gel method. TiO2 nano particles were dispersed in zinc-nickel sulphate electrolyte and thin film of Zn-Ni-TiO2 composite was generated by electrodeposition on mild steel plates. The effect of TiO2 on the corrosion behavior and hardness of the composite coatings was investigated. The film was tested for its corrosion resistance property using electrochemical, weight loss, and salt spray methods. The paper revealed higher resistance of composite coating to corrosion. Microhardness of the composite coating was determined. Scanning electron microscope images and X-ray diffraction patterns of coating revealed its fine-grain nature. Average crystalline size of the composite coating was calculated. The anticorrosion mechanism of the composite coating was also discussed.

  8. The structure and the photocatalytic activity of titania based nanotube and nanofiber coatings

    Radtke, A.; Piszczek, P.; Topolski, A.; Lewandowska, Ż.; Talik, E.; Andersen, I. Hald; Nielsen, L. Pleth; Heikkilä, M.; Leskelä, M.

    2016-04-01

    The photocatalytic activity of TiO2 based nanotube (TNT) and nanofiber (TNF) coatings has been investigated, in correlation to their structure, morphology, specific surface area, acidity and the amount of surface H2O molecules and sbnd OH groups. Characterization of these materials was carried out using grazing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). The photocatalytic activity has been quantified by two different methods, based on the photodegradation of methylene blue (the pattern of water-soluble organic pollutant) and acetone (the pattern of volatile organic pollutant), respectively. Results of our investigations revealed that TNF coatings were significantly more active in case of both photodegradation processes in air and water, as compared to TNT, even if the specific surface area of TNF films was smaller than the adequate surface area of TNT. The microstructure of produced materials, the amount of adsorbed sbnd OH groups and H2O molecules located on the surface of materials, and the acidity of the surface, were the main factors which affect their photoactivity. Photocatalytic properties of tubular and porous TiO2-based materials are the resultant of the compilation of individual factors impact and any of them cannot be neglected.

  9. Electrochemistry, a technique to prepare redox nano-structured composite materials (polymer/nano-particles) - Characterizations - Applications

    In this work is presented at first the preparation by an electrochemical way of bi functional nano-structured composite materials. It is shown that with the pulsed electrolysis techniques, it is possible to obtain metallic particles whose size and organization are controlled at the nano-scopic scale in redox matrices. Then, are presented the physico-chemical characterizations of these nano-objects (coupled in situ or ex situ at the electrochemistry). The first results relative to the catalytic activation of CO2 with these materials used as composite cathodes are indicated. (O.M.)

  10. Microalgae associated Brevundimonas sp. MSK 4 as the nano particle synthesizing unit to produce antimicrobial silver nanoparticles

    Rajamanickam, Karthic; Sudha, S. S.; Francis, Mebin; Sowmya, T.; Rengaramanujam, J.; Sivalingam, Periyasamy; Prabakar, Kandasamy

    2013-09-01

    The biosynthesis of silver nanoparticles and its antimicrobial property was studied using bacteria isolated from Spirulina products. Isolated bacteria were identified as Bacillus sp. MSK 1 (JX495945), Staphylococcus sp. MSK 2 (JX495946), Bacillus sp. MSK 3 (JX495947) and Brevundimonas sp. MSK 4 (JX495948). Silver nanoparticles (AgNPs) were synthesized using bacterial culture filtrate with AgNO3. The initial syntheses of Ag nanoparticles were characterized by UV-vis spectrophotometer (by measuring the color change to intense brown). Fourier Transform Infrared Spectroscopy (FTIR) study showed evidence that proteins are possible reducing agents and Energy-dispersive X-ray (EDX) study showing the metal silver as major signal. The structure of AgNPs was determined by Scanning electron microscopy (SEM) and X-ray diffraction (XRD). Synthesized Ag nanoparticles with an average size of 40-65 nm have antimicrobial property against human pathogens like Proteus vulgaris, Salmonella typhi, Vibrio cholera, Streptococcus sp., Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. Among the isolates Brevundimonas sp. MSK 4 alone showed good activity in both synthesis of AgNPs and antimicrobial activity. This work demonstrates the possible use of biological synthesized silver nanoparticles to combat the drug resistant problem.

  11. Analysis of the toxicity of gold nano particles on the immune system: effect on dendritic cell functions

    Villiers, Christian L., E-mail: christian.villiers@ujf-grenoble.fr; Freitas, Heidi; Couderc, Rachel; Villiers, Marie-Bernadette; Marche, Patrice N. [Inserm, U823, Centre de Recherche Albert Bonniot (France)

    2010-01-15

    The effect of manufactured gold nanoparticles (NPs) on the immune system was analysed through their ability to perturb the functions of dendritic cells (DCs), a major actor of both innate and acquired immune responses. For this purpose, DCs were produced in culture from mouse bone marrow progenitors. The analysis of the viability of the cells after their incubation in the presence of gold NPs shows that these NPs are not cytotoxics even at high concentration. Furthermore, the phenotype of the DC is unchanged after the addition of NPs, indicating that there is no activation of the DC. However, the analysis of the cells at the intracellular level reveals important amounts of gold NPs amassing in endocytic compartments. Furthermore, the secretion of cytokines is significantly modified after such internalisation indicating a potential perturbation of the immune response.

  12. Analysis of the toxicity of gold nano particles on the immune system: effect on dendritic cell functions

    The effect of manufactured gold nanoparticles (NPs) on the immune system was analysed through their ability to perturb the functions of dendritic cells (DCs), a major actor of both innate and acquired immune responses. For this purpose, DCs were produced in culture from mouse bone marrow progenitors. The analysis of the viability of the cells after their incubation in the presence of gold NPs shows that these NPs are not cytotoxics even at high concentration. Furthermore, the phenotype of the DC is unchanged after the addition of NPs, indicating that there is no activation of the DC. However, the analysis of the cells at the intracellular level reveals important amounts of gold NPs amassing in endocytic compartments. Furthermore, the secretion of cytokines is significantly modified after such internalisation indicating a potential perturbation of the immune response.

  13. Contact angle anomalies indicate that surface-active eluates from silicone coatings inhibit the adhesive mechanisms of fouling organisms.

    Meyer, Anne; Baier, Robert; Wood, Christina Darkangelo; Stein, Judith; Truby, Kathryn; Holm, Eric; Montemarano, Jean; Kavanagh, Christopher; Nedved, Brian; Smith, Celia; Swain, Geoff; Wiebe, Deborah

    2006-01-01

    Silicone coatings with critical surface tensions (CST) between 20 and 30 mN m-1 more easily release diverse types of biofouling than do materials of higher and lower CST. Oils added to these coatings selectively further diminish the attachment strengths of different marine fouling organisms, without significantly modifying the initial CST. In a search for the mechanisms of this improved biofouling resistance, the interfacial instabilities of four silicone coatings were characterised by comprehensive contact angle analyses, using up to 12 different diagnostic fluids selected to mimic the side chain chemistries of the common amino acids of bioadhesive proteins. The surfaces of painted steel test panels were characterised both before and after exposure to freshwater, brackish water, and seawater over periods ranging from 9 months to nearly 4 years. Contact angle measurements demonstrated significant surface activity of the oil-amended coatings both before and after long-term underwater exposure. The surface activity of the control (coating without oil) increased as a result of underwater exposure, consistent with mild surface chain scission and hydrolysis imparting a self-surfactancy to the coating and providing a weak boundary layer promoting continuing easy release of attaching foulants. Coatings with additives that most effectively reduced biofouling showed both initial and persistent contact angle anomalies for the test liquid, thiodiglycol, suggesting lower-shear biofouling release mechanisms based upon diminished bioadhesive crosslinking by interfering with hydrogen- and sulfhydryl bonds. Swelling of the silicone elastomeric coatings by hydrocarbon fluids was observed for all four coatings, before and after immersion. PMID:17178574

  14. Enhanced photoelectrocatalytic performance for degradation of diclofenac and mechanism with TiO2 nano-particles decorated TiO2 nano-tubes arrays photoelectrode

    In this study, TiO2 nano-particles decorated TiO2 nano-tubes arrays (TiO2 NPs/TiO2 NTAs) photoelectrodes have been successfully prepared through anodization, combined with ultrasonic strategy, followed by annealing post-treatment. The morphology and structure of the as-prepared TiO2 NPs/TiO2 NTAs photoelectrodes were characterized by scanning electrons microscopy (SEM), N2 adsorption/desorption isotherms, X-ray diffraction (XRD) and UV–visible light diffuse reflection spectroscopy (DRS). In addition, the generation of hydroxyl radicals (·OH) was detected by a photoluminescence (PL) spectra using terephthalic acid (TA) as a probe molecule. Furthermore, the photoelectrochemical (PECH) properties of TiO2 NPs/TiO2 NTAs photoanode were investigated through transient open circuit potential (OCP), photocurrent response (PCR) and electrochemical impedance spectroscopy (EIS). It was found that TiO2 NPs/TiO2 NTAs photoelectrode exhibited a distinct decrease of OCP of −0.219 mV cm−2 and PCR of 0.049 mA cm−2, while a significantly enhanced photoelectrocatalytic (PEC) efficiency of 63.6% (0.4 V vs. SCE) for the degradation of diclofenac. Moreover, the enhanced PEC mechanism of TiO2 NPs/TiO2 NTAs photoanode was proposed. The high PEC performance could be attributed to the decoration of TiO2 NPs, which could improve the mobility and separation efficiency of photoinduced charge carriers under external potential

  15. Photoelectric characterisation of aerosols and the interaction of nano-particles with ozone; Photoelektrische Aerosolcharakterisierung und die Wechselwirkung von Nanoteilchen mit Ozon

    Matter, D.

    1995-07-01

    The work presented here concerns the characterisation of particles of a diameter of less than ca. 1 {mu}m which are suspended in a carrier gas, i.e. aerosol. The importance of nano particles in the environment and for technical applications is described. Aerosol photoemission will be explained and its suitability for aerosol characterisation demonstrated. Excimer sources, which have recently been used for the photoelectric charging of particles, are described in detail with their advantages and disadvantages, when compared to conventional UV-sources. Of particular interest, is the fact that their practical design and the wavelengths available enable very high particle charges to be achieved. Since the photoactivity of a particle is highly dependent on its surface properties, it can vary considerably. Therefore, an aerosol photoemission measuring device has the properties of an extremely sensitive sensor. Combustion aerosols are detected in both immission and emission applications by using photoelectric charging. These signals can be viewed as a measure of air quality in that the measured values are proportional to the amount of PAH on the particle and correlate to other primary pollutors from combustion processes (e.g. NO, CO). In order to achieve an even more comprehensive characterisation, aerosol particles are charged in parallel by two or more UV sources of different wavelengths. The resulting photocurrent values fed into simple equations. Not only does the integral photoactivity vary strongly with the smallest changes in surface properties, but also does the charge distribution for a specific aerosol size fraction. This system, which is already in use for monitoring and control of combustion processes, may also be used for the `on-line` control of manufacturing processes which are concerned with nm-material yields. (author) figs., tabs., refs.

  16. UV-activated 7-dehydrocholesterol-coated titanium implants promote differentiation of human umbilical cord mesenchymal stem cells into osteoblasts.

    Satué, María; Ramis, Joana M; Monjo, Marta

    2016-01-01

    Vitamin D metabolites are essential for bone regeneration and mineral homeostasis. The vitamin D precursor 7-dehydrocholesterol can be used after UV irradiation to locally produce active vitamin D by osteoblastic cells. Furthermore, UV-irradiated 7-dehydrocholesterol is a biocompatible coating for titanium implants with positive effects on osteoblast differentiation. In this study, we examined the impact of titanium implants surfaces coated with UV-irradiated 7-dehydrocholesterol on the osteogenic differentiation of human umbilical cord mesenchymal stem cells. First, the synthesis of cholecalciferol (D3) was achieved through the incubation of the UV-activated 7-dehydrocholesterol coating for 48 h at 23℃. Further, we investigated in vitro the biocompatibility of this coating in human umbilical cord mesenchymal stem cells and its potential to enhance their differentiation towards the osteogenic lineage. Human umbilical cord mesenchymal stem cells cultured onto UV-irradiated 7-dehydrocholesterol-coated titanium implants surfaces, combined with osteogenic supplements, upregulated the gene expression of several osteogenic markers and showed higher alkaline phosphatase activity and calcein blue staining, suggesting increased mineralization. Thus, our results show that the use of UV irradiation on 7-dehydrocholesterol -treated titanium implants surfaces generates a bioactive coating that promotes the osteogenic differentiation of human umbilical cord mesenchymal stem cells, with regenerative potential for improving osseointegration in titanium-based bone anchored implants. PMID:25899927

  17. Physico-Chemical Condition Optimization during Biosynthesis lead to development of Improved and Catalytically Efficient Gold Nano Particles.

    Kumari, Madhuree; Mishra, Aradhana; Pandey, Shipra; Singh, Satyendra Pratap; Chaudhry, Vasvi; Mudiam, Mohana Krishna Reddy; Shukla, Shatrunajay; Kakkar, Poonam; Nautiyal, Chandra Shekhar

    2016-01-01

    Biosynthesis of nanoparticles has gained great attention in making the process cost-effective and eco-friendly, but there are limited reports which describe the interdependency of physical parameters for tailoring the dimension and geometry of nanoparticles during biological synthesis. In the present study, gold nanoparticles (GNPs) of various shapes and sizes were obtained by modulating different physical parameters using Trichoderma viride filtrate. The particles were characterized on the basis of visual observation, dynamic light scattering, UV-visible spectroscopy, transmission electron microscopy, fourier transform infrared spectroscopy, and X ray diffraction. While the size varied from 2-500 nm, the shapes obtained were nanospheres, nanotriangles, nanopentagons, nanohexagons, and nanosheets. Changing the parameters such as pH, temperature, time, substrate, and culture filtrate concentration influenced the size and geometry of nanoparticles. Catalytic activity of the biosynthesized GNP was evaluated by UV-visible spectroscopy and confirmed by gas chromatography-mass spectrometric analysis for the conversion of 4-nitrophenol into 4-aminophenol which was strongly influenced by their structure and dimension. Common practices for biodegradation are traditional, expensive, require large amount of raw material, and time taking. Controlling shapes and sizes of nanoparticles could revolutionize the process of biodegradation that can remove all the hurdles in current scenario. PMID:27273371

  18. Physico-Chemical Condition Optimization during Biosynthesis lead to development of Improved and Catalytically Efficient Gold Nano Particles

    Kumari, Madhuree; Mishra, Aradhana; Pandey, Shipra; Singh, Satyendra Pratap; Chaudhry, Vasvi; Mudiam, Mohana Krishna Reddy; Shukla, Shatrunajay; Kakkar, Poonam; Nautiyal, Chandra Shekhar

    2016-01-01

    Biosynthesis of nanoparticles has gained great attention in making the process cost-effective and eco-friendly, but there are limited reports which describe the interdependency of physical parameters for tailoring the dimension and geometry of nanoparticles during biological synthesis. In the present study, gold nanoparticles (GNPs) of various shapes and sizes were obtained by modulating different physical parameters using Trichoderma viride filtrate. The particles were characterized on the basis of visual observation, dynamic light scattering, UV-visible spectroscopy, transmission electron microscopy, fourier transform infrared spectroscopy, and X ray diffraction. While the size varied from 2–500 nm, the shapes obtained were nanospheres, nanotriangles, nanopentagons, nanohexagons, and nanosheets. Changing the parameters such as pH, temperature, time, substrate, and culture filtrate concentration influenced the size and geometry of nanoparticles. Catalytic activity of the biosynthesized GNP was evaluated by UV-visible spectroscopy and confirmed by gas chromatography-mass spectrometric analysis for the conversion of 4-nitrophenol into 4-aminophenol which was strongly influenced by their structure and dimension. Common practices for biodegradation are traditional, expensive, require large amount of raw material, and time taking. Controlling shapes and sizes of nanoparticles could revolutionize the process of biodegradation that can remove all the hurdles in current scenario. PMID:27273371

  19. Porous Silica-Coated Gold Nanorods: A Highly Active Catalyst for the Reduction of 4-Nitrophenol.

    Mohanta, Jagdeep; Satapathy, Smithsagar; Si, Satyabrata

    2016-02-01

    The successful coating of thin porous silica layers of various thicknesses [(10±1), (12±1), and (14±1) nm] on cetyl trimethylammonium bromide (CTAB) capped gold nanorods was achieved through a modified Stöber procedure. The resulting material was applied as a novel catalyst for the reduction of 4-nitrophenol. The catalytic activities of the gold nanorods increased up to eight times after coating with a layer of porous silica and the reaction followed a zero-order kinetics, having a rate constant as high as 2.92×10(-1) mol L(-1) min(-1). The spectral changes during the reduction reaction of 4-nitrophenol were observed within a very short span of time and a complete conversion to 4-aminophenol occured within 5-6 mins, including the induction period of ≈2 mins. The reusability of the catalyst was studied by running the catalytic reaction during five consecutive cycles with good efficiency without destroying the nanostructure. The methodology can be effectively applied to the development of composite catalysts with highly enhanced catalytic activity. PMID:26663755

  20. Mesoporous silica coatings for cephalosporin active release at the bone-implant interface

    Rădulescu, Dragoş; Voicu, Georgeta; Oprea, Alexandra Elena; Andronescu, Ecaterina; Grumezescu, Valentina; Holban, Alina Maria; Vasile, Bogdan Stefan; Surdu, Adrian Vasile; Grumezescu, Alexandru Mihai; Socol, Gabriel; Mogoantă, Laurenţiu; Mogoşanu, George Dan; Balaure, Paul Cătălin; Rădulescu, Radu; Chifiriuc, Mariana Carmen

    2016-06-01

    In this study, we investigated the potential of MAPLE-deposited coatings mesoporous silica nanoparticles (MSNs) to release Zinforo (ceftarolinum fosmil) in biologically active form. The MSNs were prepared by using a classic procedure with cetyltrimethylammonium bromide as sacrificial template and tetraethylorthosilicate as the monomer. The Brunauer-Emmett-Teller (BET) and transmission electron microscopy (TEM) analyses revealed network-forming granules with diameters under 100 nm and an average pore diameter of 2.33 nm. The deposited films were characterized by SEM, TEM, XRD and IR. Microbiological analyses performed on ceftaroline-loaded films demonstrated that the antibiotic was released in an active form, decreasing the microbial adherence rate and colonization of the surface. Moreover, the in vitro and in vivo assays proved the excellent biodistribution and biocompatibility of the prepared systems. Our results suggest that the obtained bioactive coatings possess a significant potential for the design of drug delivery systems and antibacterial medical-use surfaces, with great applications in bone implantology.

  1. Development of Nano-Particles Within Polymeric Materials Prepared by Gamma Radiation and their Possible Practical Applications

    Nanoparticles can be used in biomedical applications, where they facilitate laboratory diagnostics, or in medical drug targeting nanoparticles based on a core consisting of iron oxides that can be targeted through external magnets. Polyvinyl alcohol/Polyacrylic acid nanoparticles were prepared using gamma rays. The prepared PVA/AAc nano copolymers were treated with Fe2+/ Fe3+ solution followed by ammonia solution to obtain PVA/AAc-Fe3O4 nanoparticle ferrogel. Characterization of the PVA/AAc-Fe3O4 nanoparticle ferrogel was carried out using XRD, TGA, DSc , TEM and AFM. The use of magnetic field sensitive nano-ferrogels as a drug carrier was investigated. It was found that the release of drug in absence of the effect of magnetic field is mostly slow than that under the influence of magnetic field. On the other hand, development of nanoparticles within radiation grafted polymeric surfaces using electroless plating technique was investigated. Surface modification of polypropylene films (PP) was carried out via radiation induced graft copolymerization of 4-vinyl pyridine (4VP) and acrylamide (AAm) to enhance the adhesion ability of the PP surface for electroless deposition of copper. The produced grafted films were characterized by studying their FTIR and thermal stability. The prepared grafted films were copper-plated by electroless deposition using the Pd as a catalyst to initiate the redox reaction. The influences of catalytic activation method parameters on the plating rate have been studied. The electrical characteristics of the copper plated films in comparison with grafted films were studied. The results showed the high adhesion of the deposited copper film to the grafted PP film as well as high electrical conductivity. (author)

  2. Surface quality improvement of B4C particles for electroless copper coating by Cu activation and oxidation roughening methods

    Highlights: • Cu activation increases surface activity by depositing Cu nano-crystals on B4C. • The best result of Cu activation comes out at pH 12. • Oxidation roughening improves wettability of B4C by aqueous solution. • Oxidation roughening promotes Cu nucleation on B4C surface. - Abstract: Surface quality improvement by Cu activation and oxidation roughening process was studied during electroless coating Cu on boron carbide (B4C) particles. The surface morphology was characterized by scanning electron microscope (SEM) and the phase identification was determined by X-ray diffraction (XRD) analysis. Two aspects concluding surface activation and surface roughening were investigated to understand the effect of each on Cu coating. Cu activation process increased surface activity of B4C by pre-deposition Cu nano-crystals, which was effective and cost-saving when compared with conventional Pd activation method. The influence of activation pH on electroless Cu coating was discussed and a moderate pH 12 is suitable for Cu deposition. Surface roughening process availably promoted wettability of B4C particles with aqueous solution. Etched pits were formed on B4C surface and resulted in fresh surface exposed after oxidization roughening process, which was beneficial for Cu bonding and coating on B4C surface

  3. Effects of acido-basic support properties on the catalytic hydrogenation of acetylene on gold nano-particles

    Manda, Abdullah Ahmed

    Metallic gold nanoparticles supported on gamma-Al2O 3 and magnesia-alumina mixed oxide, with different magnesia content have been prepared by sol-gel method and characterized by different techniques (inductive coupled plasma-mass spectroscopy (ICP-MS), XRD, BET surface area analysis, transmission electron microscopy (TEM), CO2 and NH 3 temperature programmed desorption (TPD), H2 temperature programmed reduction (TPR) and FTIR of adsorbed CO2). Such systems were found to produce catalysts with controllable acidity, varying from catalyst possessing large density of acidic and low density of basic sites, others with acidic and basic sites of equal strength and density, and others with large basic and low acid sites densities, respectively. The catalytic assessment of the generated acidity was carried out using 2-propanol decomposition as a test reaction. The results obtained indicate that the presence of magnesia and reduced gold nanopartilces has imparted the catalysts, 1%Au/4%Mg-Al 2O3 and 1%Au/8%Mg-Al2O3, with significant base-catalytic properties. Acetylene hydrogenation and formation of coke deposits were investigated on a gold catalyst supported on gamma-Al2O3 and gold supported on alumina-magnisia mixed oxide with different gold content; 1%Au/gamma-Al 2O3, 1%Au/15%Mg-Al2O3, 2%Au/15%Mg-Al 2O3 and 4%Au/15%Mg-Al2O3. The effect of the H2/C2H2 ratio was studied over a range of values. The catalytic activity and selectivity towards ethylene and other products were investigated at different reaction temperatures. Acetylene hydrogenation was investigated in the presence and absence of ethylene in stream. It is investigated that the adsorption of the triple bond is preferred over the double bond and during selective catalytic (SCR) of C2H2 the two hydrocarbons do not compete for the same adsorption sites. The deactivation of catalysts was studied by temperature programmed oxidation (TPO). Higher content of coke over 1%Au/Al2O3 catalyst was investigated in contrast to

  4. Pulsed laser deposited praseodymium zinc molybdate coating for anticorrosion applications

    The praseodymium zinc molybdate nanopigment prepared by sol-gel was coated over SS steel 301 at 200℃ by Pulsed laser deposition for anticorrosion application. The prepared compound is a better alternative to lead, cadmium and chromium pigments, in which Cr6+ is carcinogenic, responsible for human diseases. The combination of a four-beam PLD evaporator with a suitable movement of the substrates results in a high-rate film growth on large surfaces. The nano pigment coated surface was investigated using X-ray diffraction analysis shows the combined phases of praseodymium zinc molybdate nano particles along with molybdate and praseodymium oxide, confirmed. Scanning electron microscopy shows the uniform coating without cracks and porosity on the surface. (author)

  5. Processing and characterization of activated carbon coated magnetic particles for biomedical applications

    Ramanujan, R.V. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)]. E-mail: ramanujan@ntu.edu.sg; Purushotham, S. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Chia, M.H. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2007-05-16

    Synthesis and characterization of Magnetically Targeted Carrier (MTC) powders consisting of activated carbon coated iron particles were carried out. Powders with activated carbon content of 5% by weight (Fe5C) and 35% by weight (Fe35C) were studied. Powders were synthesized via the high energy ball milling route, and the influence of milling time on the morphology, magnetic properties and drug adsorption and desorption characteristics was investigated. Physical and structural characterization included electron microscopy, size analysis, and X-ray diffraction. The magnetic properties, and theophylline adsorption and desorption characteristics were studied. Fe35C milled for 10 h was found to be a suitable candidate for MTC applications with fine size, stable magnetic properties, and superior drug adsorption and desorption behavior.

  6. Platinum-coated copper nanowires with high activity for hydrogen oxidation reaction in base.

    Alia, Shaun M; Pivovar, Bryan S; Yan, Yushan

    2013-09-11

    Platinum (Pt)-coated copper (Cu) nanowires (Pt/CuNWs) are synthesized by the partial galvanic displacement of CuNWs and have a 100 nm diameter and are 25-40 μm length. Pt/CuNWs are studied as a hydrogen oxidation reaction (HOR) catalyst in base along with Cu templated Pt nanotubes (PtNT (Cu)), a 5% Cu monolayer on a bulk polycrystalline Pt electrode (5% ML Cu/BPPt), BPPt, and carbon supported Pt (Pt/C). Comparison of these catalysts demonstrates that the inclusion of Cu benefited the HOR activity of Pt/CuNWs likely by providing compressive strain on Pt; surface Cu further aids in hydroxyl adsorption, thereby improving the HOR activity of Pt/CuNWs. Pt/CuNWs exceed the area and mass exchange current densities of carbon supported Pt by 3.5 times and 1.9 times. PMID:23952885

  7. Nanostructured titanium-silver coatings with good antibacterial activity and cytocompatibility fabricated by one-step magnetron sputtering

    Bai, Long; Hang, Ruiqiang; Gao, Ang; Zhang, Xiangyu; Huang, Xiaobo; Wang, Yueyue; Tang, Bin; Zhao, Lingzhou; Chu, Paul K.

    2015-11-01

    Bacterial infection and loosing are serious complications for biomedical implants in the orthopedic, dental, and other biomedical fields and the ideal implants should combine good antibacterial ability and bioactivity. In this study, nanostructured titanium-silver (Ti-Ag) coatings with different Ag contents (1.2 to 21.6 at%) are prepared on Ti substrates by magnetron sputtering. As the Ag concentration is increased, the coatings change from having dense columnar crystals to sparse ones and eventually no columnar structure. The Ti-Ag coatings can effectively kill Staphylococcus aureus during the first few days and remain moderately antibacterial after immersion for 75 days. Compared to pure Ti, the Ti-Ag coatings show good cytocompatibility as indicated by good osteoblast adhesion, proliferation, intracellular total protein synthesis, and alkaline phosphatase (ALP) activity. In addition, cell spreading, collagen secretion, and extracellular matrix mineralization are promoted on the coatings with the proper Ag contents due to the nanostructured morphological features. Our results indicate that favorable antibacterial activity and osseointegration ability can be simultaneously achieved by regulating the Ag contents in Ti-Ag coatings.

  8. Temperature dependence of oxygen reduction activity at Nafion-coated bulk Pt and Pt/carbon black catalysts.

    Yano, Hiroshi; Higuchi, Eiji; Uchida, Hiroyuki; Watanabe, Masahiro

    2006-08-24

    Oxygen reduction reaction (ORR) activity and H(2)O(2) formation at Nafion-coated film electrodes of bulk-Pt and Pt nanoparticles dispersed on carbon black (Pt/CB) were investigated in 0.1 M HClO(4) solution at 30 to 110 degrees C by using a channel flow double electrode method. We have found that the apparent rate constants k(app) (per real Pt active surface area) for the ORR at bulk-Pt (with and without Nafion-coating) and Nafion-coated Pt/CB (19.3 and 46.7 wt % Pt, d(Pt) = 2.6 to 2.7 nm) thin-film electrodes were in beautiful agreement with each other in the operation conditions of polymer electrolyte fuel cells (PEFCs), i.e., 30-110 degrees C and ca. 0.7 to 0.8 V vs RHE. The H(2)O(2) yield was 0.6-1.0% at 0.7-0.8 V on all Nafion-coated Pt/CB and bulk-Pt and irrespective of Pt-loading level and temperature. Nafion coating was pointed out to be a major factor for the H(2)O(2) formation on Pt catalysts modifying the surface property, because H(2)O(2) production was not detected at the bulk-Pt electrode without Nafion coating. PMID:16913788

  9. Decreased material-activation of the complement system using low-energy plasma polymerized poly(vinyl pyrrolidone) coatings

    Andersen, Thomas E; Palarasah, Yaseelan; Skjødt, Mikkel-Ole;

    2011-01-01

    In the current study we investigate the activation of blood complement on medical device silicone rubber and present a plasma polymerized vinyl pyrrolidone (ppVP) coating which strongly decreases surface-activation of the blood complement system. We show that uncoated silicone and polystyrene are...

  10. Activated Carbon Prepared From Orange Peels Coated With Titanium Oxide Nanoparticles: Characterization and Applications in the Decomposition of Nox

    Liliana Giraldo

    2014-06-01

    Full Text Available In this work, we report the degradation of NOx using two catalysts prepared by coating activated carbon from orange peels with TiO2. This study compared the performance of TiO2-coated catalysts prepared by CVD (AC1/TiO2 and the sol-gel method (AC2/TiO2. The catalysts were characterized by X-ray diffraction, BET surface area and TEM. The photocatalytic activity was measured by studying the degradation of NOx in the vapor phase. The results show that the catalyst synthesized by the CVD method was more efficient in the decomposition of NOx. TEM and XRD revealed the presence of a mixture of the anatase and rutile phases, which favors the NOx decomposition process. Nitrogen isotherms showed that coating the nanoparticles with titanium oxide did not significantly change the surface area of the original activated carbon.

  11. Control of substrate oxidation in MOD ceramic coating on low-activation ferritic steel with reduced-pressure atmosphere

    Tanaka, Teruya, E-mail: teru@nifs.ac.jp; Muroga, Takeo

    2014-12-15

    Highlights: • A Cr{sub 2}O{sub 3} layer was produced on a ferritic steel substrate with a reduced-pressure. • The Cr{sub 2}O{sub 3} layer prevents further substrate oxidation in following coating process. • The Cr{sub 2}O{sub 3} layer has a function as a hydrogen permeation barrier. • A smooth MOD Er{sub 2}O{sub 3} coating was successfully made on the Cr{sub 2}O{sub 3} layer by dip coating. • The Cr{sub 2}O{sub 3} layer would enhance flexibility in MOD coating process and performances. - Abstract: An Er{sub 2}O{sub 3} ceramic coating fabricated using the metal–organic decomposition (MOD) method on a Cr{sub 2}O{sub 3}-covered low-activation ferritic steel JLF-1 substrate was examined to improve hydrogen permeation barrier performance of the coating. The Cr{sub 2}O{sub 3} layer was obtained before coating by heat treating the substrate at 700 °C under reduced pressures of <5 × 10{sup −3} Pa and 5 Pa. The Cr{sub 2}O{sub 3} layer was significantly stable even with heat treatment at 700 °C in air. This layer prevented further production of Fe{sub 2}O{sub 3}, which has been considered to degrade coating performance. An MOD Er{sub 2}O{sub 3} coating with a smooth surface was successfully obtained on a Cr{sub 2}O{sub 3}-covered JLF-1 substrate by dip coating followed by drying and baking. Preprocessing to obtain a Cr{sub 2}O{sub 3} layer would provide flexibility in the coating process for blanket components and ducts. Moreover, the Cr{sub 2}O{sub 3} layer suppressed hydrogen permeation through the JLF-1 substrate. While further optimization of the coating fabrication process is required, it would be possible to suppress hydrogen permeation significantly by multilayers of Cr{sub 2}O{sub 3} and MOD oxide ceramic.

  12. In Vitro Antifungal Activity against Oral Candida Species Using a Denture Base Coated with Silver Nanoparticles

    Yoshiaki Kamikawa

    2014-01-01

    Full Text Available Although oral Candida easily adheres to denture base materials, many denture detergents are effective only against bacteria but not against Candida. Silver nanoparticles (AgNPs, which are known to have potent antibacterial and antifungal activity, have been used in the prevention of oral candidiasis (OC. We evaluated the adherence of Candida albicans and Candida glabrata on a heat-cured Acron resin piece supported by AgNPs by low-vacuum scanning electron microscopy (SEM and measuring colony-forming units. C. albicans and C. glabrata increasingly adhered to the resin surface of the control piece over time, but the adhesion AgNP of both Candida species to the AgNP-coated surface was significantly inhibited (P<0.001. Low-vacuum SEM revealed that C. albicans and C. glabrata on the resin surface of control pieces appeared as oval colonies, with a major axis of 3-4 μm and a smooth cell wall, but those on the AgNP-coated resin surface were less abundant than the control and showed swollen yeast features, with a major axis of more than 5 μm and a corrugated cell wall. Our results suggest a way to prevent denture-associated OC by using denture base materials processed by AgNPs.

  13. Comparative Evaluation of Antifungal Effect of Titanium, Zirconium and Aluminium Nanoparticles Coated Titanium Plates Against C. albicans

    Mohandoss, Karthikeyan; Balasubramaniam, Muthu Kumar

    2016-01-01

    Introduction The topographical modifications may vary from millimeter wide grooves to nano size structures. Recently growing nano technology is rapidly advancing surface engineering in implant dentistry. This advancement has resulted in difference in surface properties including the morphology, chemistry, crystal structure and mechanical properties of the implant. Aim To evaluate the anticandidal effect of titanium, zirconium and aluminium nanoparticles against C. albicans at 24 hours, 72 hours and one week time interval. Materials and Methods According to ISO/TR 11175:1993, the samples were prepared with the dimension of 20mm diameter and 1mm thickness in grade IV titanium. A total of 40 samples were made and the samples were divided into four groups. The samples without coating were Group-A (control), samples coated with titanium nano particles were Group-B, samples coated with zirconium nano particles were Group-C and samples coated with aluminium nano particles were Group-D. The samples were cleaned by sonicating in acetone and subsequently in water three times for 15 min. Then they were treated with TiO2, ZrO2 and Al2O3 nanoparticles. The discs were sterilized under uv radiation and placed in SDA for C.albicans. The colonies were counted in 24, 72 hours and one week intervals. Results The values were statistically analyzed using one-way ANOVA and Tukey HSD Test. Significance p-value was < .001, which showed that significant difference in C.F.U among the groups in titanium coated samples at 24 hours, 72 hours and one week time intervals. Conclusion TiO2 nanoparticles coated titanium plates showed significant anticandidal effect compared to ZrO2 and Al2O3 nanoparticles at 24, 72 hours and one week time interval. PMID:26894177

  14. Study of physical properties of nano-silica coated cotton textiles

    This research was aimed to investigate the effect of silica sol-gel coating on air permeability, stiffness and tensile properties of dyed cotton fabric. Various concentrations of silica nanoparticles were applied on dyed cotton substrate using two different cross-linkers through sol-gel method. The homogenous sol-gel coating dispersions were prepared by using an ultrasonicator. Coated samples were tested for mechanical and comfort properties such as tensile strength, stiffness, crease recovery and air permeability. It was found that tensile strength and crease recovery of coated substrate were slightly improved. On other hand, it was observed that fabric stiffness and air permeability were affected slightly by increasing concentration of silica nano particle. It was also observed that type of cross-linker has strong influence on coated fabrics strength and flexural rigidity. (author)

  15. Electrochemical Corrosion Characteristics of Arc-Ion-Plated AlTiN Coating for Marine Application.

    Lee, Jung-Hyung; Kim, MyoungJun; Kim, Seong-Jong

    2016-02-01

    In this study, aluminum titanium nitride (AlTiN) coating was deposited by arc ion plating onto mirror finish STS 304 plate. The surface and cross-section of the coating was characterized by SEM and EDX analysis. Several electrochemical corrosion experiments were performed including rest potential measurement, potentiodynamic polarization experiment and Tafel analysis. The result of the experiments indicated that the AlTiN coating presented lower corrosion current density than the substrate material (STS 304) under uniform corrosion environment. It was also observed that AlTiN coating may have a risk of being attacked by localized corrosion attack such as pitting when pores or micro/nano particles in the coating are exposed to chloride ion containing corrosion environment, especially marine environment. PMID:27433658

  16. Antioxidant activity and bioaccessibility of phenols-enriched edible casein/caseinate coatings during in vitro digestion.

    Helal, Ahmed; Desobry, Stephane; Banon, Sylvie; Shamsia, Sherif M

    2015-02-01

    Active films were developed for food coating applications. Entrapped phenol susceptibility to digestion was studied. Sodium caseinate (Na-CN) coatings were formulated with 0, 10, 20% Casein (CN) incorporating selected phenols as model antioxidants. This study investigated phenol/CN/Na-CN interactions, in vitro bioaccessibility of phenols and CN role in phenols retention during in vitro gastric and pancreatic digestion. The antioxidant activity of catechin (CAT), rutin (RUT), chlorogenic acid (CHL), gallic acid (GAL), and tannic acid (TA) in coatings varied with the phenolic compound type and CN concentration and was related to phenol hydrophobic binding to CN. ABTS method gave activities ranged from 412 down to 213, and DPPH method gave values from 291·7 to 190·9. An inverse relationship was found with CN content due to CN/phenol interaction. During digestion, a part of phenols was degraded by alkaline pH of pancreatic fluid. Simultaneously, CN proteolysis led to release of phenols and the bioaccessibility index remained above 80% for all phenols. The results suggested the possibility of protecting phenols against oxidation and digestive alteration by entrapment in CN and Na-CN coating films. These positive results showed the ability to produce antioxidant-enriched edible coatings to increase food protection and phenol nutritional intake. PMID:25327452

  17. Active bio-based food-packaging: Diffusion and release of active substances through and from cellulose nanofiber coating toward food-packaging design.

    Lavoine, Nathalie; Guillard, Valérie; Desloges, Isabelle; Gontard, Nathalie; Bras, Julien

    2016-09-20

    Cellulose nanofibers (CNFs) were recently investigated for the elaboration of new functional food-packaging materials. Their nanoporous network was especially of interest for controlling the release of active species. Qualitative release studies were conducted, but quantification of the diffusion phenomenon observed when the active species are released from and through CNF coating has not yet been studied. Therefore, this work aims to model CNF-coated paper substrates as controlled release system for food-packaging using release data obtained for two model molecules, namely caffeine and chlorhexidine digluconate. The applied mathematical model - derived from Fickian diffusion - was validated for caffeine only. When the active species chemically interacts with the release device, another model is required as a non-predominantly diffusion-controlled release was observed. From caffeine modeling data, a theoretical active food-packaging material was designed. The use of CNFs as barrier coating was proved to be the ideal material configuration that best meets specifications. PMID:27261728

  18. Functional photocatalytically active and scratch resistant antireflective coating based on TiO2 and SiO2

    Mazur, M.; Wojcieszak, D.; Kaczmarek, D.; Domaradzki, J.; Song, S.; Gibson, D.; Placido, F.; Mazur, P.; Kalisz, M.; Poniedzialek, A.

    2016-09-01

    Antireflection (AR) multilayer coating, based on combination of five TiO2 and SiO2 thin films, was deposited by microwave assisted reactive magnetron sputtering process on microscope glass substrates. In this work X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy and wettability measurements were used to characterize the structural and surface properties of the deposited coating. These studies revealed that prepared coating was amorphous with low surface roughness. Photocatalytic properties were determined based on phenol decomposition reaction. Measurements of optical properties showed that transmittance in the visible wavelength range was increased after the deposition of AR coating as-compared to bare glass substrate. The mechanical properties were determined on the basis of nano-indentation and scratch resistance tests. Performed research has shown that deposition of an additional thin 10 nm thick TiO2 thin film top layer, the prepared AR coating was photocatalytically active, hydrophobic, scratch resistant and had increased hardness as-compared to bare glass substrate. These results indicate that prepared AR multilayer could be used also as a self-cleaning and protective coating.

  19. PRESERVATION OF H2 PRODUCTION ACTIVITY IN NANOPOROUS LATEX COATINGS OF RHODOPSEUDOMONAS PALUSTRIS CGA009 DURING DRY STORAGE AT AMBIENT TEMPERATURES

    Milliken, C.; Piskorska, M.; Soule, T.; Gosse, J.; Flickinger, M.; Smith, G.; Yeager, C.

    2012-08-27

    To assess the applicability of latex cell coatings as an "off-the-shelf' biocatalyst, the effect of osmoprotectants, temperature, humidity and O{sub 2} on preservation of H{sub 2} production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H{sub 2} production. Beyond 2 weeks of storage, sorbitol- treated coatings lost all H{sub 2} production activity, whereas considerable H{sub 2} production was still detected in sucrose- and trehalose-stabilized coatings. The relative humidity level at which the coatings were stored had a significant impact on the recovery and subsequent rates of H{sub 2} production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H{sub 2} (0-0.1% headspace accumulation), whereas those stored at <5% humidity retained 27-53% of their H{sub 2} production activity after 8 weeks of storage. When stored in argon at <5% humidity and room temperature, R. palustris coatings retained full H{sub 2} production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Overall, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of bioactivity in the dry state.

  20. Permittivity and Electromagnetic Interference Shielding Investigations of Activated Charcoal Loaded Acrylic Coating Compositions

    Sharief ud Din Khan

    2014-01-01

    Full Text Available Acrylic resin (AR based electromagnetic interference (EMI shielding composites have been prepared by incorporation of up to 30 wt% activated charcoal (AC in AR matrix. These composites have been characterized by XRD, Raman spectroscopy, scanning electron microscopy, dielectric, and EMI shielding measurement techniques. XRD patterns and Raman studies confirm the incorporation of AC particles inside AR matrix and suggest possible interactions between phases. The SEM images show that incorporation of AC particles leads to systematic change in the morphology of composites especially the formation of porous structure. The dielectric measurements show that 30 wt% AC loading composite display higher relative permittivity value (~79 compared to pristine AR (~5. Further, the porous structure, electrical conductivity, and permittivity value contribute towards EMI shielding effectiveness value of −36 dB (attenuation of >99.9% of incident radiation for these composites, thereby demonstrating their suitability for making efficient EMI shielding coatings.

  1. Corrosion resistance enhancement of Ni-P electroless coatings by incorporation of nano-SiO2 particles

    Composite coatings were prepared using hypophosphite reduced electroless nickel bath containing 7 g/L SiO2 nano-particles at pH 4.6 ± 0.2 and temperature 90 ± 2 oC. Deposition rate for SiO2 nano-composite coatings was 10-12 μm/h. The amount of SiO2 nano-particles co-deposited in the Ni-P matrix was around 2 wt.%. The analyzes of coating compositions, carried out by Energy Dispersive Analysis of X-ray (EDAX), showed that plain Ni-P and Ni-P/nano-SiO2 deposits contained around 8 wt.% phosphorus. The X-ray diffraction (XRD) pattern of Ni-P/nano-SiO2 coating was very similar to that of plain electroless Ni-P coating, whose structure was also amorphous. Scanning electron microscopy (SEM) morphology of the surface deposits revealed that some agglomeration occurred because of the absence of surfactant. Electrochemical impedance spectroscopy and polarization tests showed that addition of nano-SiO2 particles demonstrated significant improvement of corrosion resistance of Ni-P coatings in salty atmosphere.

  2. Chitosan acetate as an active coating material and its effects on the storing of Prunus avium L.

    Dang, Qi Feng; Yan, Jing Quan; Li, Yan; Cheng, Xiao Jie; Liu, Cheng Sheng; Chen, Xi Guang

    2010-03-01

    In this article, chitosan acetate (CA) was prepared by the method of solid-liquid reaction. CA was a stable faint yellow powder with water solubility. CA kept the same backbone in the chemical structure as the raw material of chitosan, and it also had the similar antibacterial properties with chitosan. CA could form a coating film on the outside surface of the sweet cherries, could effectively retard the loss of the water, titratable acidity, and ascorbic acid of sweet cherries, and could induce a significant increase in the peroxidase and catalase activities in the fruit. The CA coating could also increase the ratio of the total soluble solids and titratable acidity in the fruit. The application of CA effectively maintained quality attributes and extended postharvest life of the sweet cherries. The results revealed that the CA salts had potential application in active edible coating materials in the storage of fresh fruit. PMID:20492258

  3. TiO2/PVP纳米微粒改性聚氨酯皮革涂饰剂的研究%Polyurethane Leather Finishing Agent Modified by TiO2/PVP Nano - particles

    潘卉; 肖莎莎; 赵甜; 吴志申

    2012-01-01

    采用TiCl4为原料,低温下通过液相水解的方法制备了金红石型纳米TiO2,利用聚乙烯吡咯烷酮(PVP)对纳米TiO2进行了原位表面改性。分别利用傅立叶红外光谱仪(FT-IR)、X-射线衍射仪(XRD)、透射电子显微镜(TEM)和热分析仪(TG-DTA)对改性前后的纳米TiO2进行了分析表征。试验发现:PVP改性后的纳米TiO2(TiO2/PVP)在聚氨酯皮革涂饰材料中具有很好的分散性,将TiO2/PVP添加到此涂饰剂中,制备了系列TiO2/PVP/聚氨酯复合薄膜,结果表明,TiO2/PVP纳来微粒显著提高了薄膜涂层的抗紫外线能力、耐溶剂性和耐磨性能。%The rutile TiO2 nano - particles were prepared by the liquidoid hydrolyzation of Titanium tetrachloride ( TiCl4 ) at low temperature. The TiO2 nano- particles were modified via in situ with polyvinylpyrrolidone(PVP). The nano- particles were characterized by Fourier transform infrared spectroscopy ( FT - IR ), X - ray diffraction pattern ( XRD ), transmission electron microscopy (TEM) and thermogravimetric - differential thermal analyses (TG - DTA). It shows that the TiO2/PVP nano - parti- eles are well dispersed in the polyurethane leather finishing agent. A series of TiO2/PVP/ polyurethane rained. The results indicate that the TiO2/PVP nano - particles improves efficiently the UV - resistant, abrasion resistance. composite film are ob- solvent resistance and

  4. Elaboration of silicon carbides nano particles (SiC): from the powder synthesis to the sintered ceramic; Elaboration de ceramiques nanostructurees en carbure de silicium (SiC): de la synthese de poudre a la ceramique frittee

    Reau, A. [CEA Saclay, Dept. des Materiaux pour le Nucleaire (DEN/DANS/DMN/SRMA), 91 - Gif-sur-Yvette (France)

    2008-07-01

    Materials for the reactor cores of the fourth generation will need materials supporting high temperatures with fast neutrons flux. SiC{sub f}/SiC ceramics are proposed. One of the possible elaboration process is to fill SiC fiber piece with nano particles SiC powder and to strengthen by sintering. The aim of this thesis is to obtain a nano structured SiC ceramic as a reference for the SiC{sub f}/SiC composite development and to study the influence of the fabrication parameters. (A.L.B.)

  5. Preparation and application of magnetic Fe3O4 nano-particles%磁性纳米Fe3O4粒子的制备与应用

    张杰; 胡登华

    2011-01-01

    In order to summarize and review the preparation and application of magnetic Fe3O4 nano-particles, the preparation methods of magnetic Fe3O4 nano-particles was overviewed in this paper, including mechanical milling method, precipitation method, microemulsion method, solvothermal method, sol-gel method and pyrolysis method of organics. The advantages and disadvantages of each method were briefly analyzed. Applications of magnetic Fe3O4 nano-particles in ferrofluid, magnetic recording material, biomedicine, catalyst carrier and so on, were introduced. Finally, the focus and application prospect for magnetic Fe3O4 nano-particles in the future were predicted.%为了对磁性纳米Fe3O4颗粒的制备和应用进行总结和回顾,综述了磁性纳米Fe3O4颗粒的机械研磨法、沉淀法、微乳液法、溶剂热法、溶胶-凝胶法、热分解有机物法等几种主要制备方法,分析了各制备方法的特点;介绍了磁性纳米Fe3O4颗粒在磁流体、磁记录材料、生物医学以及催化剂载体等领域的应用,并对磁性纳米Fe3O4颗粒未来的研究重点和应用前景进行了展望:如何更经济更环保地制备粒径可控且分布均匀的磁性纳米Fe3O4微粒是今后研究的热点与重点;纳米Fe3O4颗粒同时具备磁性颗粒和纳米颗粒的双重优势的应用性研究也极为重要.

  6. Preparations of nano-particles, nano-composites and fibers of ZnO from an amide precursor: Photocatalytic decomposition of (CH3)2S2 in a continuous flow reactor

    High surface area hexagonal ZnO nano-particles were obtained at room temperature from hydrolysis of the amide derivative Zn[N(SiMe3)2]2. The same procedure applied on silica or cellulose substrates led to homogeneous crack-free hybrid materials for which micro- down to nano-meter replication into ZnO cloth was achieved by calcination at 700 deg. C. These materials were characterized by FT-IR, UV-vis, photoluminescence, X-ray diffraction (XRD) and transmission electron microscopy (TEM). They demonstrated enhanced photocatalytic degradation of a tough pollutant such as CH3SSCH3 compared with commercial ZnO powder

  7. Bactericidal activity under UV and visible light of cotton fabrics coated with anthraquinone-sensitized TiO2

    Rahal, Raed

    2013-06-01

    This study describes a method derived from ISO/TC 206/SC specifications to assess the bactericidal activity against a bacterial strain, Pseudomonas fluorescens, of various photocatalytic fabrics, under UVA and filtered visible light. The experimental method allowed the accurate quantification of bacteria survival on photoactive surfaces and films under UVA and UV-free visible irradiation. Cotton fabrics coated with TiO2, anthraquinone or anthraquinone-sensitized TiO2 display a significant bactericidal efficiency. TiO2-coated fabrics are very efficient against P. fluorescens after 4 h UVA irradiation (bacteria survival below the detection limit). Under UVA-free visible light, anthraquinone-sensitized TiO2 coated fabrics induced a significant bactericidal activity after 2 h irradiation, while anthraquinone alone-coated fabrics were not as efficient and TiO2 coated fabrics were almost inefficient. These results show that although exhibiting a weak n-π* band in the 350-420 nm range, anthraquinone is a good candidate as an efficient visible light photosensitizer. A synergy effect between anthraquinone and TiO2 was demonstrated. A possible reaction mechanism, involving a synergy effect for singlet oxygen formation with anthraquinone-sensitized TiO2 is proposed to account for these results. © 2012 Elsevier B.V. All rights reserved.

  8. Mechanisms of antibacterial activity and stability of silver nanoparticles grown on magnetron sputtered TiO2 coatings

    K Zawadzka; A Kisielewska; I Piwoński; K Kądzioła; A Felczak; S Różalska; N Wrońska; K Lisowska

    2016-02-01

    Nanomaterials with high stability and efficient antibacterial activity are of considerable interest. The preparation of silver nanoparticles (AgNPs) on titania coatings and their effective antibacterial activity against Staphylococcus aureus ATCC 6538 were reported. Titanium dioxide (TiO2) coatings with AgNPs were prepared on Si wafers using the reactive magnetron sputtering method. The surface topography of AgNPs/TiO2 coatings imaged using scanning electron microscopy revealed that the size and surface density of AgNPs grown by the photoreduction of silver ions were dependent on the concentration of AgNO3 in the primary solution and the time of TiO2 exposure to UV illumination. Evaluation of the antimicrobial properties and surface analysis before and after the biological test of AgNPs/TiO2 coatings indicates their high antimicrobial stability and durability. Furthermore, the interdependence between the concentration of released silver and bacterial growth inhibition was demonstrated. In addition, direct contact killing and released silver-mediated killing have been proposed as a bactericidal mechanism of action of tested coatings with AgNPs.

  9. Functionalization of PDMS modified and plasma activated two-component polyurethane coatings by surface attachment of enzymes

    This article describes a new strategy for coupling the enzyme horseradish peroxidase to a two-component polyurethane (2C-PUR) coating. A stable polymer conjugate was achieved by combining the enzyme and the 2C-PUR coating which was modified with poly(dimethylsiloxane) (PDMS), located at the surface. An atmospheric pressure plasma jet system was used to convert alkyl groups from the PDMS into polar silanol functionalities. This conversion was proven by X-ray photoelectron spectroscopy and dynamic contact angle measurements. In addition, the stability of the activated 2C-PUR surface containing silanol groups was determined by measuring the contact angle as a function of time. Compared to the non-modified 2C-PUR systems the one with PDMS displayed a higher stability over a time period over 28 h. In a silanization process the coating was treated with (3-aminopropyl) trimethoxysilane and the enzyme was subsequently immobilized to the coating via the cross linker glutaraldehyde to receive new biomimetic catalytic/enzymatic functions. The chemical immobilization (chemisorption) of the enzyme to the surface showed statistically significant higher biological activity as compared to references samples without using a cross linker (physisorption). The presented technique offers the opportunity to design new and smart multifunctional surface coatings which employ biomimetic capabilities.

  10. Biofunctional composite coating architectures based on polycaprolactone and nanohydroxyapatite for controlled corrosion activity and enhanced biocompatibility of magnesium AZ31 alloy

    Zomorodian, A., E-mail: amir.zomorodian@ist.utl.pt [ICEMS-DEQ, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Garcia, M.P. [Laboratory for Bone Metabolism and Regeneration, Faculty of Dental Medicine, University of Porto, Porto (Portugal); Moura e Silva, T. [ICEMS-DEQ, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); ISEL, Department of Mechanical Engineering, 1959-007 Lisboa (Portugal); Fernandes, J.C.S. [ICEMS-DEQ, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Fernandes, M.H. [Laboratory for Bone Metabolism and Regeneration, Faculty of Dental Medicine, University of Porto, Porto (Portugal); Montemor, M.F. [ICEMS-DEQ, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2015-03-01

    In this work a biofunctional composite coating architecture for controlled corrosion activity and enhanced cellular adhesion of AZ31 Mg alloys is proposed. The composite coating consists of a polycaprolactone (PCL) matrix modified with nanohydroxyapatite (HA) applied over a nanometric layer of polyetherimide (PEI). The protective properties of the coating were studied by electrochemical impedance spectroscopy (EIS), a non-disturbing technique, and the coating morphology was investigated by field emission scanning electron microscopy (FE-SEM). The results show that the composite coating protects the AZ31 substrate. The barrier properties of the coating can be optimized by changing the PCL concentration. The presence of nanohydroxyapatite particles influences the coating morphology and decreases the corrosion resistance. The biocompatibility was assessed by studying the response of osteoblastic cells on coated samples through resazurin assay, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The results show that the polycaprolactone to hydroxyapatite ratio affects the cell behavior and that the presence of hydroxyapatite induces high osteoblastic differentiation. - Highlights: • A biofunctional coating architecture for bioresorbable AZ31 Mg alloys is proposed. • The composite coating provides corrosion protection of the bare material. • The coating enhances alkaline phosphatase activity of osteoblastic cells. • The presence of hydroxyapatite results in higher osteoblastic differentiation.

  11. Biofunctional composite coating architectures based on polycaprolactone and nanohydroxyapatite for controlled corrosion activity and enhanced biocompatibility of magnesium AZ31 alloy

    In this work a biofunctional composite coating architecture for controlled corrosion activity and enhanced cellular adhesion of AZ31 Mg alloys is proposed. The composite coating consists of a polycaprolactone (PCL) matrix modified with nanohydroxyapatite (HA) applied over a nanometric layer of polyetherimide (PEI). The protective properties of the coating were studied by electrochemical impedance spectroscopy (EIS), a non-disturbing technique, and the coating morphology was investigated by field emission scanning electron microscopy (FE-SEM). The results show that the composite coating protects the AZ31 substrate. The barrier properties of the coating can be optimized by changing the PCL concentration. The presence of nanohydroxyapatite particles influences the coating morphology and decreases the corrosion resistance. The biocompatibility was assessed by studying the response of osteoblastic cells on coated samples through resazurin assay, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The results show that the polycaprolactone to hydroxyapatite ratio affects the cell behavior and that the presence of hydroxyapatite induces high osteoblastic differentiation. - Highlights: • A biofunctional coating architecture for bioresorbable AZ31 Mg alloys is proposed. • The composite coating provides corrosion protection of the bare material. • The coating enhances alkaline phosphatase activity of osteoblastic cells. • The presence of hydroxyapatite results in higher osteoblastic differentiation

  12. Activated platelets form protected zones of adhesion on fibrinogen and fibronectin-coated surfaces

    1993-01-01

    Leukocytes form zones of close apposition when they adhere to ligand- coated surfaces. Because plasma proteins are excluded from these contact zones, we have termed them protected zones of adhesion. To determine whether platelets form similar protected zones of adhesion, gel-filtered platelets stimulated with thrombin or ADP were allowed to adhere to fibrinogen- or fibronectin-coated surfaces. The protein- coated surfaces with platelets attached were stained with either fluorochrome-conjugate...

  13. 10 Years-Activities at ONERA on Advanced Thermal Barrier Coatings

    Bacos, M. P; Dorvaux, J.M.; Landais, S.; Lavigne, O.; Mévrel, R.; M. Poulain; Rio, C; Vidal-Sétif, M.H.

    2011-01-01

    Developing thermal barrier coatings operating at higher temperature and/or for very long durations (commercial aircraft applications) is one of the technological and economical challenges for engine manufacturers. This includes the search for (i) low thermal conductivity, high thermal stability and CMAS resistant ceramic top coat, and (ii) alternative low cost bond coat with improved oxidation resistance and chemical compatibility with the substrate. This paper reviews the rationale sustainin...

  14. Synthesis of bio-active titanium oxide coatings stimulated by electron-beam plasma

    Vasilieva Tatiana

    2014-11-01

    Full Text Available Advantages of the electron-beam plasma (EBP for production of bioactive titanium oxide coatings were experimentally studied. The coatings were synthesized in EBP of oxygen on the surface of plane titanium substrates. A number of analytical techniques were used to characterize morphology, chemical composition, and structure of the synthesized titanium oxide. The analysis showed the titanium oxide (IV in the rutile form to predominate in the coatings composition.

  15. Synthesis of bio-active titanium oxide coatings stimulated by electron-beam plasma

    Vasilieva Tatiana; Sokolov Igor; Sigarev Andrey; Tun Win Aung

    2014-01-01

    Advantages of the electron-beam plasma (EBP) for production of bioactive titanium oxide coatings were experimentally studied. The coatings were synthesized in EBP of oxygen on the surface of plane titanium substrates. A number of analytical techniques were used to characterize morphology, chemical composition, and structure of the synthesized titanium oxide. The analysis showed the titanium oxide (IV) in the rutile form to predominate in the coatings composition.

  16. Modulation of hepatocarcinoma cell morphology and activity by parylene-C coating on PDMS.

    Nazaré Pereira-Rodrigues

    Full Text Available BACKGROUND: The ability to understand and locally control the morphogenesis of mammalian cells is a fundamental objective of cell and developmental biology as well as tissue engineering research. We present parylene-C (ParC deposited on polydimethylsiloxane (PDMS as a new substratum for in vitro advanced cell culture in the case of Human Hepatocarcinoma (HepG2 cells. PRINCIPAL FINDINGS: Our findings establish that the intrinsic properties of ParC-coated PDMS (ParC/PDMS influence and modulate initial extracellular matrix (ECM; here, type-I collagen surface architecture, as compared to non-coated PDMS substratum. Morphological changes induced by the presence of ParC on PDMS were shown to directly affect liver cell metabolic activity and the expression of transmembrane receptors implicated in cell adhesion and cell-cell interaction. These changes were characterized by atomic force microscopy (AFM, which elucidated differences in HepG2 cell adhesion, spreading, and reorganization into two- or three-dimensional structures by neosynthesis of ECM components. Local modulation of cell aggregation was successfully performed using ParC/PDMS micropatterns constructed by simple microfabrication. CONCLUSION/SIGNIFICANCE: We demonstrated for the first time the modulation of HepG2 cells' behavior in relation to the intrinsic physical properties of PDMS and ParC, enabling the local modulation of cell spreading in a 2D or 3D manner by simple microfabrication techniques. This work will provide promising insights into the development of cell-based platforms that have many applications in the field of in vitro liver tissue engineering, pharmacology and therapeutics.

  17. High-performance organic solar cells with spray-coated hole-transport and active layers

    Girotto, Claudio; Heremans, Paul [IMEC vzw-Organic Photovoltaics, Kapeldreef 75, B-3001 Leuven (Belgium); ESAT, Katholieke Universiteit Leuven, Kasteelpark Arenberg 10, B-3001 Leuven (Belgium); Moia, Davide [IMEC vzw-Organic Photovoltaics, Kapeldreef 75, B-3001 Leuven (Belgium); Politecnico di Milano, via Golgi 40, 20133 Milano (Italy); Rand, Barry P. [IMEC vzw-Organic Photovoltaics, Kapeldreef 75, B-3001 Leuven (Belgium)

    2011-01-07

    In this study, we report high performance organic solar cells with spray coated hole-transport and active layers. With optimized ink formulations we are able to deposit films with controlled thickness and very low surface roughness (<10 nm). Specifically we deposit smooth and uniform 40 nm thick films of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as well as films composed of a mixture of poly(3-hexyl thiophene) (P3HT) and the C{sub 60}-derivative (6,6)-phenyl C61-butyric acid methyl ester (PCBM) with thicknesses in the range 200-250 nm. To control film morphology, formation and thickness, the optimized inks incorporate two solvent systems in order to take advantage of surface tension gradients to create Marangoni flows that enhance the coverage of the substrate and reduce the roughness of the film. Notably, we achieve fill factors above 70% and attribute the improvement to an enhanced P3HT crystallization, which upon optimized post-drying thermal annealing results in a favorable morphology. As a result, we could extend the thickness of the layer to several hundreds of nanometers without noticing a substantial decrease of the transport properties of the layer. By proper understanding of the spreading and drying dynamics of the inks we achieve spray coated devices with power conversion efficiency of 3.75%, with fill factor, short circuit current and open circuit voltage of 70%, 9.8 mA cm{sup -2} and 550 mV, respectively. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. The structure and molecular orientation of polytetrafluoroethylene coatings deposited from active gas phase

    The molecular structure of polytetrafluoroethylene (PTFE) coatings deposited on aluminium substrates was investigated by the method of attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). It has been shown experimentally that PTFE coatings deposited by the electron-beam dispersion method have molecular orientation and are ordered nonmonotonously during the process of coating growth. Maximum order and orientation of molecules along the normal to the substrate are observed in an interfacial layer located within up to 100 nm to the substrate. The observed morphological and orientation features of the formed layers were explained using the proposed adsorption-diffusion mechanism of polymer coating formation.

  19. Preparation and Anti-infrared Property of CR-39 Modified With Nuclear Tracks and Silver Nano-particles%核径迹-银纳米颗粒改性的CR-39材料制备及其抗红外反射性能

    刘存兄; 黄东辉; 胡炼; 倪邦发; 田伟之; 樊启文; 肖才锦; 聂鹏; 王平生; 张贵英

    2011-01-01

    CR-39 samples were irradiated with sulphur ions from HI-13 tandem accelerator to produce latent tracks at China Institute of Atomic Energy. Ultraviolet light with wavelength 360 nm was used to sensitize the bombarded CR-39 samples before chemical etching by NaOH solution. The latent tracks were then developed into pores or holes with certain diameter. Silver black was coated on the surface of etched CR-39 using evaporation in inert gas argon ambience. The SEM images indicate that the silver nano-particles are 60-100 nm in diameter at the pressure of 50-100 Pa, and the diameter of spherical clusters formed by nano-particles is 3 μm. The reflectivity indices were measured for all CR-39 samples, untreated and treated with above-mentioned procedures, within the wavelength of 2. 5-25 μm. The results indicate that CR-39 modified with a combination of solid state nuclear tracks and silver black coating can decrease the reflec-tivity index to 0. 9% for the wavelength range of 8. 0-25 μm, and that is 82% reduction compared to CR-39 without modification. The blank reflectivity indices of CR-39 at wavelength of 5.8 μm and 7.8 μm are reduced from 9.0% and 13.0% to 5.0% and 6.8%, respectively.%本工作用中国原子能科学研究院HI-13串列加速器提供的32S离子辐照CR-39样品,产生潜径迹,用紫外灯敏化后在氢氧化钠溶液中蚀刻,使潜径迹成为具有一定孔径的孔(洞).用真空充氩气的方法在核径迹孔样品表面镀银纳米颗粒.电子扫描电镜图片显示,氩气压强在50~100 Pa之间时,银纳米颗粒直径约为60~100 nm,纳米颗粒形成球状团簇的大小为3 μm.在红外光区(2.5~25μm)测量镀膜样品的反射率,测量结果表明,CR-39表面的核径迹与银纳米颗粒能将红外光区(8.0~25 μm)的反射率降低到0.9%,与未经改性的CR-39比较,减低了82%.在5.8和7.8 μm处,CR-39的本底反射率分别从9.0%和13.0%降低到了5.0%和6.8%.

  20. CCN activation experiments with adipic acid: effect of particle phase and adipic acid coatings on soluble and insoluble particles

    S. S. Hings

    2008-07-01

    Full Text Available Slightly soluble atmospherically relevant organic compounds may influence particle CCN activity and therefore cloud formation. Adipic acid is a frequently employed surrogate for such slightly soluble organic materials. The 11 published experimental studies on the CCN activity of adipic acid particles are not consistent with each other nor do they, in most cases, agree with the Köhler theory. The CCN activity of adipic acid aerosol particles was studied over a significantly wider range of conditions than in any previous single study. The work spans the conditions of the previous studies and also provides alternate methods for producing "wet" (deliquesced solution droplets and dry adipic acid particles without the need to produce them by atomization of aqueous solutions. The experiments suggest that the scatter in the previously published CCN measurements is most likely due to the difficulty of producing uncontaminated adipic acid particles by atomization of solutions and possibly also due to uncertainties in the calibration of the instruments. The CCN activation of the small (dm<150 nm initially dry particles is subject to a deliquescence barrier, while for the larger particles the activation follows the Köhler curve. Wet adipic acid particles follow the Köhler curve over the full range of particle diameters studied. In addition, the effect of adipic acid coatings on the CCN activity of both soluble and insoluble particles has also been studied. When a water-soluble core is coated by adipic acid, the CCN-hindering effect of particle phase is eliminated. An adipic acid coating on hydrophobic soot yields a CCN active particle. If the soot particle is relatively small (dcore≤102 nm, the CCN activity of the coated particles approaches the deliquescence line of adipic acid, suggesting that the total size of the particle determines CCN activation and the soot core acts as a scaffold.

  1. Photocatalytic activity of Ho-doped anatase titanium dioxide coated magnetite.

    Shi, Zhongliang; Xiang, Yongfang; Zhang, Xiaoyan; Yao, Shuhua

    2011-01-01

    A composite photocatalyst (Ho/TiO(2)/Fe(3)O(4)) with Ho-doped anatase titanium dioxide (Ho/TiO(2)) shell and a magnetite core was prepared by coating photoactive Ho/TiO(2) onto a magnetic Fe(3)O(4) core through the hydrolysis of tetrabutyltitanate (Ti(OBu)(4), TBT) in water/oil (w/o) microemulsion with precursors of Ho(NO(3))(3) and TBT in the presence of Fe(3)O(4) nanoparticles. The morphological, structural and optical properties of the prepared samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-Vis diffusive reflectance spectroscopy (UV-Vis DRS). The effect of Ho ion content on the photocatalytic activity was studied. The photodegradation behavior of the prepared photocatalyst under UV and visible light was investigated in aqueous solution using methyl orange (MO) as target pollutant. The results showed that the prepared photocatalyst was activated by visible light and used as effective catalyst in photo-oxidation reactions. In addition, the possibility of cyclic usage of the prepared photocatalyst was also confirmed. Moreover, Ho/TiO(2) was tightly bound to Fe(3)O(4) and could be easily recovered from the medium by a simple magnetic process. It can therefore be potentially applied for the treatment of water contaminated by organic pollutants. PMID:21208216

  2. Identification of seed coat phenolic compounds from differently colored pea varieties and characterization of their antioxidant activity

    Stanisavljević Nemanja S.

    2015-01-01

    Full Text Available The phenolic composition of seed coats in four differently colored pea varieties (Pisum sativum L. was investigated using UHPLC-LTQ OrbiTrap MS. The obtained findings revealed that the seed coats of the examined pea genotypes possess a unique phenolic composition compared to previously studied European cultivars. In total, 41 phenolic compounds have been identified. The seed coats of the studied cultivars contained certain amounts of rosmarinic acid, rutin, galangin, morin, naringin, hesperetin and pinocembrin as well as ten flavonol glycosides that had not been reported previously. Additionally, the total phenolic content, antioxidant activity and metal chelating capacity of extracts was determined using Folin-Ciocalteu’s method, 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, ferric ion-reducing capacity and ferrous ion-chelating capacity assay, respectively. Dark colored genotypes MBK 168 and MBK 173 possessed the highest total phenolic contents as well the strongest antioxidant activities. On the other hand, bright colored genotypes MBK 88 and MBK 90 exhibited the strongest metal-chelating capacities. The examined pea seed coats may be considered as important potential contributors to human health due to the presence of bioactive phenolic constituents. In addition, our results could be used as a guideline for breeding new pea cultivars with high antioxidant activities applicable in the formulation of functional food products. [Projekat Ministarstva nauke Republike Srbije, br. 173005 i br. 172017

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

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

    2010-03-15

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

  4. Synthesis of La-doped Li2MnSiO4 nano-particle with high-capacity via polyol-assisted hydrothermal method

    Highlights: • La-doped Li2MnSiO4/C materials are prepared by polyol-assisted hydrothermal method. • High capacity for Li2MnSiO4/C is obtained by doping 1 at.% La3+. • The utilization ratio of active mass of La-doped Li2MnSiO4/C is obviously improved. • La3+ doping enhances Li+ diffusion and decreases charge transfer resistance. - Abstract: Li2Mn1LaxSiO4/C (x = 0, 0.01 and 0.04) composites are prepared via a polyol-assisted hydrothermal method followed by carbon coating. X-ray diffraction patterns confirm that the unit cell volume of Li2MnSiO4 has been enlarged by doping a small amount of La3+. The scanning electron micrographs and elemental maps indicate that the sizes of the Li2MnSiO4 particles can be reduced by homogeneously doping La3+. The transmission electron microscopy shows the well crystallized Li2MnSiO4 nanoparticles. The electrochemical performances of all samples are evaluated by galvanostatic charge/discharge tests and electrochemical impedance spectroscopy. 1 at.% La3+ doped Li2MnSiO4 (AL1) delivers the highest initial discharge capacity of about 257 mAh g−1, corresponding to the intercalation of about 1.55 lithium ions per formula unit. AL1 also exhibits improved capacity retentions of about 51.1%. The above improvements of electrochemical properties are related to the decreased charge transfer resistance and enhanced lithium ion diffusion for La-doped samples, whose crystal structure is maintained and lattice has been slightly enlarged

  5. The n-MAO/EPD bio-ceramic composite coating fabricated on ZK60 magnesium alloy using combined micro-arc oxidation with electrophoretic deposition

    Xiong, Ying; Lu, Chao; Wang, Chao; Song, Renguo

    2014-12-01

    A bio-ceramic composite coating was fabricated on ZK60 magnesium (Mg) alloy using combined micro-arc oxidation (MAO) with electrophoretic deposition (EPD) technique. The MAO coating as the basal layer was produced in alkaline electrolyte with (n-MAO coating) and without (MAO coating) the addition of CeO2 and ZrO2 nano-particles, respectively. A hydroxyapatite (HA) coating as the covering layer was deposited on the n-MAO coating to improve the biological properties of the coating (n-MAO/EPD composite coating). The morphology and phase composition of three treated coatings were investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD). The corrosion resistance of these coatings was evaluated with potentiodynamic polarization tests and immersion tests in simulated body fluid (SBF) at 36.5 ± 0.5 °C. The XRD spectra showed that the CeO2 and ZrO2 peaks can be collected in the n-MAO coating, and HA particles exists in the n-MAO/EPD composite coating. The results of corrosion tests indicated that the n-MAO/EPD composite coating owned increased bioactivity and long-term protective ability compared with the MAO coating and the n-MAO coating. Thus Mg alloy coated with the n-MAO/EPD composite coating should be more suited as biodegradable bone implants.

  6. First experience of activation of NEG coated racetrack Aluminium alloy vacuum chambers of undulators in Indus-2

    NEG (Non evaporable Getter) coated long racetrack Aluminium alloy undulator vacuum chambers were installed in two vacuum segments areas LS2 (Long Straight section 2) and LS3 (Long Straight section 3) of Indus-2. The baking and activation methodology adopted was different as compared to being used for uncoated chambers. The bakeout cycle adopted was to decrease the outgassing rate of the uncoated vacuum chambers of Aluminium and stainless steel components and to activate the NEG thin film. Bake-out control was done using in house developed distributed temperature controller and graphical interface on PC. The control system supports up to 40 channel temperature control and 8 channel vacuum monitoring over RS-485 network. Graphical interface provides user friendly features for auto set point control, data logging and troubleshooting. The main challenges involved in the bake- out and the activation of the NEG coated chambers is presented and discussed. (author)

  7. Microcrystalline coatings deposited by series double-pole electro-pulse discharge and its high-temperature oxidation behavior

    XU; Qiang; (徐强); HE; Yedong; (何业东); WANG; Deren; (王德仁); QI; Huibin; (齐慧滨); LI; Zhengwei; (李正伟); GAO; Wei; (高唯)

    2002-01-01

    A new technique--series electro-pulse discharge (SEPD)--was developed as a surface coating process. In this process, both positive and negative poles of a pulse power were used as the depositing electrodes and the substrate alloy was used as an induction electrode. The physical process for such SEPD was tested by measuring the relationship between the discharge voltages and gaps in a pin-plate-pin system. Microcrystalline Ni20Cr alloy coatings and oxide- dispersed Ni20Cr alloy coatings were prepared on Ni20Cr alloy surface by using a vibrating SEPD device. Oxidation at 950℃ in ambient air showed that the microcrystalline Ni20Cr alloy coatings greatly improved the oxidation resistance of the substrate alloy. The addition of dispersed Y2O3 nano-particles into the microcrystalline coatings was found to further reduce the oxidation rate and enhance the oxide spallation resistance.

  8. Fusion peptide P15-CSP shows antibiofilm activity and pro-osteogenic activity when deposited as a coating on hydrophilic but not hydrophobic surfaces.

    Li, Xian; Contreras-Garcia, Angel; LoVetri, Karen; Yakandawala, Nandadeva; Wertheimer, Michael R; De Crescenzo, Gregory; Hoemann, Caroline D

    2015-12-01

    In the context of porous bone void filler for oral bone reconstruction, peptides that suppress microbial growth and promote osteoblast function could be used to enhance the performance of a porous bone void filler. We tested the hypothesis that P15-CSP, a novel fusion peptide containing collagen-mimetic osteogenic peptide P15, and competence-stimulating peptide (CSP), a cationic antimicrobial peptide, has emerging properties not shared by P15 or CSP alone. Peptide-coated surfaces were tested for antimicrobial activity toward Streptoccocus mutans, and their ability to promote human mesenchymal stem cell (MSC) attachment, spreading, metabolism, and osteogenesis. In the osteogenesis assay, peptides were coated on tissue culture plastic and on thin films generated by plasma-enhanced chemical vapor deposition to have hydrophilic or hydrophobic character (water contact angles 63°, 42°, and 92°, respectively). S. mutans planktonic growth was specifically inhibited by CSP, whereas biofilm formation was inhibited by P15-CSP. MSC adhesion and actin stress fiber formation was strongly enhanced by CSP, P15-CSP, and fibronectin coatings and modestly enhanced by P15 versus uncoated surfaces. Metabolic assays revealed that CSP was slightly cytotoxic to MSCs. MSCs developed alkaline phosphatase activity on all surfaces, with or without peptide coatings, and consistently deposited the most biomineralized matrix on hydrophilic surfaces coated with P15-CSP. Hydrophobic thin films completely suppressed MSC biomineralization, consistent with previous findings of suppressed osteogenesis on hydrophobic bioplastics. Collective data in this study provide new evidence that P15-CSP has unique dual capacity to suppress biofilm formation, and to enhance osteogenic activity as a coating on hydrophilic surfaces. PMID:26097095

  9. A Comparative Study of the Anti-Fungal Activity of Zinc Oxide and Titanium Dioxide Nano and Bulk Particles with Anti-Fungals against Fungi Isolated from Infected Skin and Dandruff Flakes

    Sara A George

    2014-06-01

    Full Text Available The anti-fungal activity of Zinc oxide and Titanium dioxide nano-particles was assessed by treating eight fungal cultures - Aspergillus niger, Trichophyton, Fonsecaea, Aspergillus flavus, Rhizopus oryzae, Fusarium, Ramichloridium schulzeri and Cladosporium, isolated from infected skin and dandruff flakes with the nanoparticles and analysing the extent of growth inhibition on agar and in broth media. The anti-fungal activity of these nano-particles was also compared to that of their respective bulk-particular forms, as well as to two commonly used anti-fungals, namely Amphotericin-B and Miconazole. The nano-particles were found to be more effective than the bulk-particles and almost equally efficient as Amphotericin-B, however Miconazole was found to be a better anti-fungal at an equal concentration. Zinc oxide nano-particles were better anti-fungals than Titanium dioxide, thus its anti-fungal activity at different concentrations was assessed to identify the concentration that shows similar anti-fungal activity as 3μg/ml of Miconazole. The reason for performing this study was to investigate the possibility of replacing presently used anti-fungal drugs with nano-particles in topical applications to treat mycosis.

  10. Integrating high electrical conductivity and photocatalytic activity in cotton fabric by cationizing for enriched coating of negatively charged graphene oxide.

    Sahito, Iftikhar Ali; Sun, Kyung Chul; Arbab, Alvira Ayoub; Qadir, Muhammad Bilal; Jeong, Sung Hoon

    2015-10-01

    Electroconductive textiles have attended tremendous focus recently and researchers are making efforts to increase conductivity of e-textiles, in order to increase the use of such flexible and low cost textile materials. In this study, surface conductivity and photo catalytic activity of standard cotton fabric (SCF) was enhanced by modifying its surface charge, from negative to positive, using Bovine Serum Albumin (BSA) as a cationic agent, to convert it into cationised cotton fabric (CCF). Then, both types of fabrics were dip coated with a simple dip and dry technique for the adsorption of negatively charged graphene oxide (GO) sheets onto its surface. This resulted in 67.74% higher loading amount of GO on the CCF making self-assembly. Finally, this coating was chemically converted by vapor reduction using hydrazine hydrate to reduced graphene oxide (rGO) for restoration of a high electrical conductivity at the fabric surface. Our results revealed that with such high loading of GO, the surface resistance of CCF was only 40Ω/sq as compared to 510Ω/sq of the SCF and a 66% higher photo catalytic activity was also achieved through cationization for improved GO coating. Graphene coated SCF and CCF were characterized using FE-SEM, FTIR, Raman, UV-vis, WAXD, EDX and XPS spectroscopy to ascertain successful reduction of GO to rGO. The effect of BSA treatment on adsorption of cotton fabric was studied using drop shape analyzer to measure contact angle and for thermal and mechanical resistance, the fabric was tested for TGA and tensile strength, respectively. rGO coated fabric also showed slightly improved thermal stability yet a minor loss of strength was observed. The high flexibility, photocatalytic activity and excellent conductivity of this fabric suggests that it can be used as an electrode material for various applications. PMID:26076630

  11. Tritium permeation experiments using reduced activation ferritic/martensitic steel tube and erbium oxide coating

    Highlights: • Tritium permeation has been measured on uncoated and Er2O3-coated F82H tubes. • Surface effects were observed in permeation tests with 1.2–40 ppm tritium. • HTO was formed by isotope exchange reactions at Er2O3-coated surfaces. • High-performance Er2O3 coatings could be fabricated on tubular F82H substrates. - Abstract: Low concentration tritium permeation experiments have been performed on uncoated F82H and Er2O3-coated tubular samples in the framework of the Japan-US TITAN collaborative program. Tritium permeability of the uncoated sample with 1.2 ppm tritium showed one order of magnitude lower than that with 100% deuterium. The permeability of the sample with 40 ppm tritium was more than twice higher than that of 1.2 ppm, indicating a surface contribution at the lower tritium concentration. The Er2O3-coated sample showed two orders of magnitude lower permeability than the uncoated sample, and lower permeability than that of the coated plate sample with 100% deuterium. It was also indicated that the memory effect of ion chambers in the primary and secondary circuits was caused by absorption of tritiated water vapor that was generated by isotope exchange reactions between tritium and surface water on the coating

  12. Engineered Theranostic Magnetic Nanostructures: Role of Composition and Surface Coating on Magnetic Resonance Imaging Contrast and Thermal Activation.

    Nandwana, Vikas; Ryoo, Soo-Ryoon; Kanthala, Shanthi; De, Mrinmoy; Chou, Stanley S; Prasad, Pottumarthi V; Dravid, Vinayak P

    2016-03-23

    Magnetic nanostructures (MNS) have emerged as promising functional probes for simultaneous diagnostics and therapeutics (theranostic) applications due to their ability to enhance localized contrast in magnetic resonance imaging (MRI) and heat under external radio frequency (RF) field, respectively. We show that the "theranostic" potential of the MNS can be significantly enhanced by tuning their core composition and architecture of surface coating. Metal ferrite (e.g., MFe2O4) nanoparticles of ∼8 nm size and nitrodopamine conjugated polyethylene glycol (NDOPA-PEG) were used as the core and surface coating of the MNS, respectively. The composition was controlled by tuning the stoichiometry of MFe2O4 nanoparticles (M = Fe, Mn, Zn, ZnxMn1-x) while the architecture of surface coating was tuned by changing the molecular weight of PEG, such that larger weight is expected to result in longer length extended away from the MNS surface. Our results suggest that both core as well as surface coating are important factors to take into consideration during the design of MNS as theranostic agents which is illustrated by relaxivity and thermal activation plots of MNS with different core composition and surface coating thickness. After optimization of these parameters, the r2 relaxivity and specific absorption rate (SAR) up to 552 mM(-1) s(-1) and 385 W/g were obtained, respectively, which are among the highest values reported for MNS with core magnetic nanoparticles of size below 10 nm. In addition, NDOPA-PEG coated MFe2O4 nanostructures showed enhanced biocompatibility (up to [Fe] = 200 μg/mL) and reduced nonspecific uptake in macrophage cells in comparison to other well established FDA approved Fe based MR contrast agents. PMID:26936392

  13. Low activation steels welding with PWHT and coating for ITER test blanket modules and DEMO

    Aubert, P.; Tavassoli, F.; Rieth, M.; Diegele, E.; Poitevin, Y.

    2011-02-01

    EUROFER weldability is investigated in support of the European material properties database and TBM manufacturing. Electron Beam, Hybrid, laser and narrow gap TIG processes have been carried out on the EUROFER-97 steel (thickness up to 40 mm), a reduced activation ferritic-martensitic steel developed in Europe. These welding processes produce similar welding results with high joint coefficients and are well adapted for minimizing residual distortions. The fusion zones are typically composed of martensite laths, with small grain sizes. In the heat-affected zones, martensite grains contain carbide precipitates. High hardness values are measured in all these zones that if not tempered would degrade toughness and creep resistance. PWHT developments have driven to a one-step PWHT (750 °C/3 h), successfully applied to joints restoring good material performances. It will produce less distortion levels than a full austenitization PWHT process, not really applicable to a complex welded structure such as the TBM. Different tungsten coatings have been successfully processed on EUROFER material. It has shown no really effect on the EUROFER base material microstructure.

  14. Apatite formation on active nanostructured coating based on functionalized gold nanoparticles

    Vasile, Eugeniu [METAV Research and Development (Romania); Serafim, Andrada; Dragusin, Diana-Maria; Petrea, Celina; Iovu, Horia; Stancu, Izabela-Cristina, E-mail: stancu.c.i@gmail.com [University Politehnica of Bucharest, Advanced Polymer Materials Group (Romania)

    2012-06-15

    In this work, we developed a simple method of surface functionalization of polymer substrates to provide them with the ability to form biomimetic hydroxyapatite (HA) when incubated in synthetic body fluids (SBF). In a first step, gold nanoparticles (AuNPs) were used as surface nanostructuring units for a biocompatible polymer, poly(2-hydroxyethyl methacrylate), known to not promote biomineralization in SBF, and under physiological conditions. The treatment of AuNPs-modified substrate with mercaptosuccinic acid leads to brushes of carboxyl-ended chains self-assembled onto the gold-polymer hybrid nanosurface. The main aim of this work was to demonstrate that these multianionic nanosurfaces would induce HA formation when incubated in solutions mimicking physiologic conditions. The formation of apatite and its morphology and composition were successfully investigated by means of high resolution scanning and transmission electron microscopy with energy dispersive X-ray microanalysis, infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Emphasis was put on the nucleation of HA in areas with agglomerated carboxyl-ended functionalized nanoparticles. The results obtained in this study may unlock new applications for smart active coatings based on functionalized AuNPs, such as the induction of biomineralization.

  15. Silver coated anionic cellulose nanofiber composites for an efficient antimicrobial activity.

    Gopiraman, Mayakrishnan; Jatoi, Abdul Wahab; Hiromichi, Seki; Yamaguchi, Kyohei; Jeon, Han-Yong; Chung, Ill-Min; Ick Soo, Kim

    2016-09-20

    Herein, we report a comparative study of silver coated anionic cellulose nanocomposite before (CMC-Ag) and after (AgNPs/CMC) chemical reduction for antibacterial activity. Cellulose nanofibers were prepared by deacetylation of electrospun cellulose acetate nanofibers, which were then treated with sodium chloroacetate to prepare anionic cellulose nanofibers (CMC). Aqueous AgNO3 solution with different concentrations was employed to produce nanofiber composites. To obtain AgNPs/CMC, the resultant Ag/CMC nanofibers were chemically reduced with NaBH4. The nanocomposites were characterized by FE-SEM, FTIR, XPS and SEM-EDS. Antimicrobiality tests were conducted using S. aureus and Escherichia coli bacteria following standard test method JIS L1902, 2008. The EDS results confirmed higher silver content in CMC-Ag nanofibers than AgNPs/CMC nanofibers. The antimicrobial test and EDS results demonstrated higher silver release (larger halo width) by the former in comparison to later which confers better antimicrobiality by CMC-Ag nanofibers. PMID:27261729

  16. Development of chitosan-coated gold nanoflowers as SERS-active probes

    Surface-enhanced Raman scattering (SERS) has been intensely researched for many years as a potential technique for highly sensitive detection. This work, through the reduction of HAuCl4 with pyrrole in aqueous solutions, investigated a facile one-pot synthesis of flower-like Au nanoparticles with rough surfaces. The formation process of the Au nanoflowers (AuNFs) was carefully studied, and a spontaneous assembly mechanism was proposed based on the time-course experimental results. The key synthesis strategy was to use pyrrole as a weak particle stabilizing and reducing agent to confine crystal growth in the limited ligand protection region. The nanometer-scale surface roughness of AuNFs provided several hot spots on a single particle, which significantly increased SERS enhancement. Good biocompatible stable Raman-active probes were synthesized by coating AuNFs with chitosan. The conservation of the SERS effects in living cells suggested that the chitosan-capped AuNFs could be suitable for highly sensitive detection and have potential for targeting of tumors in vivo.

  17. Apatite formation on active nanostructured coating based on functionalized gold nanoparticles

    In this work, we developed a simple method of surface functionalization of polymer substrates to provide them with the ability to form biomimetic hydroxyapatite (HA) when incubated in synthetic body fluids (SBF). In a first step, gold nanoparticles (AuNPs) were used as surface nanostructuring units for a biocompatible polymer, poly(2-hydroxyethyl methacrylate), known to not promote biomineralization in SBF, and under physiological conditions. The treatment of AuNPs-modified substrate with mercaptosuccinic acid leads to brushes of carboxyl-ended chains self-assembled onto the gold-polymer hybrid nanosurface. The main aim of this work was to demonstrate that these multianionic nanosurfaces would induce HA formation when incubated in solutions mimicking physiologic conditions. The formation of apatite and its morphology and composition were successfully investigated by means of high resolution scanning and transmission electron microscopy with energy dispersive X-ray microanalysis, infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Emphasis was put on the nucleation of HA in areas with agglomerated carboxyl-ended functionalized nanoparticles. The results obtained in this study may unlock new applications for smart active coatings based on functionalized AuNPs, such as the induction of biomineralization.

  18. The Photocatalytic Activity of Nano-TiO2 (anatase) Gradient Coating on Tourmaline Beads

    Gradient nano-TiO2(anatase) /tourmaline beads were prepared by sol impregnated method, and the phase composition and microstructure of gradient coating were characterized by XRD and SEM, and the photocatalytic activity were evaluated by degradation of methyl orange (MO), compared with that of pure nano-TiO2 (anatase), tourmaline beads. The result indicated that the MO degradation ratio by tourmaline beads is 5.8%; that by pure nano-TiO2 (anatase) is 38.2%; while the MO degradation ratio approached 70.4% by gradient nano-TiO2 (anatase) /tourmaline beads, much better than the other two types of catalysts. When the gradient nano-TiO2 (anatase) /tourmaline beads are illuminated by UV irradiation, the electron-hole pairs are generated and the photogenerated carrier will be adsorbed tightly on the anode of tourmaline, owing to its strong electrostatic field, which suppresses the recombination of the electron-hole pairs, and enhances photocatalytic efficiency.

  19. Photocatalytic and biocidal activities of novel coating systems of mesoporous and dense TiO2-anatase containing silver nanoparticles

    Here we describe the development of novel nanostructured coating systems with improved photocatalytic and antibacterial activities. These systems comprise a layer of SiO2 followed by a layer of mesoporous or dense TiO2-anatase, and doping with silver nanoparticles (Ag NPs). The coatings were synthesized via a sol–gel technique by combining colloidal Ag NPs with TiO2 and SiO2 sols. The photocatalytic activity was studied through methyl orange decomposition under UV light. Results showed a great increase of photocatalytic activity by Ag NPs doping. The most active photocatalyst corresponded to the Ag–SiO2/TiO2 mesoporous system, associated with the porosity of the coatings and with the decrease of e–h recombination for the presence of Ag NPs. All the TiO2 coatings showed a strong bactericidal activity against planktonic forms of Gram-negative (enterohemorrhagic Escherichia coli) and Gram-positive (Listeria monocytogenes) pathogens, as well as a strong germicidal effect against deadly spores of human gas gangrene- and anthrax-producing bacteria (Clostridium perfringens and Bacillus anthracis, respectively). The bactericidal and sporocidal activity was improved by doping the coatings with Ag NPs, even more when nanoparticles were in the outer layer of TiO2, because they are more accessible to the environment. The mechanisms responsible for the increase of photocatalytic and bactericidal behaviors related to Ag NP doping were studied by spectroscopic ellipsometry, UV–vis spectroscopy, photoluminescence and anodic stripping voltammetry. It was found that the separation of the electron–hole pair contributed to the enhancement of photocatalysis, whereas the effect of the local electric field reinforcement was probably present. A possible involvement of a decrease of band-gap energy and dispersion by silver nanoparticles is ruled out. bactericidal efficacy was increased by Ag+ ion release. Overall, the results included in this article show that the architecture of

  20. Determination of the photocatalytic activity of TiO2 coatings on clay roofing tile substrates methylene blue as model pollutant

    Skapin Andrea S.

    2009-01-01

    Full Text Available The photocatalytically active mesoporous coatings, based on titanium dioxide sols (Degussa, of the fired clay roofing tiles substrate were prepared by using poly(ethylene glycol (PEG M-600 and M-4000, as the structure directing agents. The coatings were deposited using spray technique followed by thermal treatment. Photocatalytic activity of the TiO2 coatings was evaluated by aqueous solution of methylene blue as model dye, deposited on the top of the coatings, after irradiation with UV light. The results were compared with the photocatalytic efficiency of some commercial self-cleaning products (clay roofing tiles, glass. The newly design coatings showed an interesting decolourisation performance (over 30 % after 24 h. It appeared that the procedure of photocatalytic activity determination, in the case of porous substrates, should be renewed by a preadsorption process.

  1. Formulation, selection and application of coatings for radio-active facilities

    The use of appropriate coatings on materials involved in the handling radioactivity substantially reduces the effort required for decontamination. Development and performance are demonstrated for materials of choice. Future directions and requirements are indicated

  2. Antibacterial activity of reactive quaternary ammonium compounds in solution and in nonleachable coatings

    Gozzelino, G.; Romero Tobar, D.E.; Chaitiemwong, N.; Hazeleger, W.C.; Beumer, R.R.

    2011-01-01

    Antibacterial polymers suitable for coating applications without leaching of the biocidal component have been obtained by UV copolymerization of acrylic resins with acrylic monomers containing quaternary ammonium moieties. Suitable reactive biocides, based on quaternary ammonium monomers (QAMs), end

  3. Effect of Additives on UV-Activated Urethane Acrylate Polymerization Composite Coatings

    Zane GRIGALE-SOROCINA; Martins KALNINS; Jana SIMANOVSKA; Elīna VINDEDZE; Ingmars BIRKS; Evita BRAZDAUSKA

    2016-01-01

    An increased demand for new and improved coating systems, for environmental & health & safety and performance reasons, have appeared during the recent decades. Currently, there is new interest in preparation of thin UV curable urethane acrylate (UA) composite coatings with short-term properties. Cellulose based additives: nitrocellulose, cellulose acetate butyrate, sucrose benzoate and silica were evaluated to determine their influence on unreacted composite characteristics (viscosity, pigmen...

  4. Experimental Analysis of Tablet Properties for Discrete Element Modeling of an Active Coating Process

    Just, Sarah; Toschkoff, Gregor; Funke, Adrian; Djuric, Dejan; Scharrer, Georg; Khinast, Johannes; Knop, Klaus; Kleinebudde, Peter

    2013-01-01

    Coating of solid dosage forms is an important unit operation in the pharmaceutical industry. In recent years, numerical simulations of drug manufacturing processes have been gaining interest as process analytical technology tools. The discrete element method (DEM) in particular is suitable to model tablet-coating processes. For the development of accurate simulations, information on the material properties of the tablets is required. In this study, the mechanical parameters Young’s modulus, c...

  5. Investigation of antimicrobial activity and morphological properties of metal coated textile surfaces

    The results of investigation antimicrobial and surface properties of the textiles metal coated by means of magnetron or the cleaning-deposition system, which is based on sequentially arranged DC anode layer accelerator and hollow cathode, are presented. The antimicrobial properties against bacteria E. coli and S. aureus of cotton and polyester/cotton textiles coated by Cu, Ti and Ag with the use of two different systems were examined and compared.

  6. Unprecedented photocatalytic activity of carbon coated/MoO3 core-shell nanoheterostructurs under visible light irradiation

    Ghaffar, Iqra; Warsi, Muhammad Farooq; Shahid, Muhammad; Shakir, Imran

    2016-05-01

    We reveal that nano-scale carbon layer deposited by hydrothermal process on molybdenum oxide (MoO3) nanowires surface significantly improve the light absorption range. Furthermore, the graphene-carbon coated MoO3 nanocopmosite (rGO/C-MoO3 nanocomposite) exhibits excellent chemical stability and enhanced photocatalytic activity for methylene blue in aqueous solution under visible light irradiation compared to the bare MoO3 nanowires and carbon coated MoO3 nanowires (C-MoO3 nanowires). The enhanced photocatalytic activity of rGO/C-MoO3 nanocomposite could be attributed to the extended light absorption range, better adsorptivity of dye molecules and efficient separation of photogenerated electrons and holes. Overall, this work provides new insights that the as synthesized rGO/C-MoO3 nanocomposite can be efficiently used as high performance photocatalysts to improve the environmental protection issues under visible light irradiation.

  7. Bovine Serum Albumin and Chitosan Coated Silver Nanoparticles and Its Antimicrobial Activity against Oral and Nonoral Bacteria

    León Francisco Espinosa-Cristóbal; Gabriel Alejandro Martínez-Castañón; Juan Pablo Loyola-Rodríguez; Nereyda Niño-Martínez; Facundo Ruiz; Norma Verónica Zavala-Alonso; Lara, René H.; Simón Yobanny Reyes-López

    2015-01-01

    Antimicrobial agents have been developed for drug-resistance infections, which have been rapidly increasing; however, the control of involved microorganisms is still a challenge. In this work, SNP with bovine serum albumin (BSA) and chitosan (CS) coatings were prepared with an aqueous reduction method, characterized using dispersion light scattering, transmission electron microscopy, and thermal analysis. Antibacterial activity was tested on seven oral and nonoral bacteria by microdilution te...

  8. Antimicrobial activity of novel nanostructured Cu-SiO2 coatings prepared by chemical vapour deposition against hospital related pathogens

    Varghese, Sajnu; ElFakhri, Souad O; Sheel, David W.; Sheel, Paul; Bolton, Frederick J Eric; Foster, Howard A

    2013-01-01

    There is increasing recognition that the healthcare environment acts as an important reservoir for transmission of healthcare acquired infections (HCAI). One method of reducing environmental contamination would be use of antimicrobial materials. The antimicrobial activity of thin silica-copper films prepared by chemical vapour deposition was evaluated against standard strains of bacteria used for disinfectant testing and bacteria of current interest in HCAI. The structure of the coatings was ...

  9. Non-UV based germicidal activity of metal-doped TiO2 coating on solid surfaces

    LIU Li-fen; John Barford; YEUNG King Lun; SI Grace

    2007-01-01

    A stain-based screening method was developed to screen different catalyst coatings for their germicidal activity. A Baclight dead/live bacteria viability kit (invitrogen, molecular probes) was used for staining the cell. The screening was carried out following a standard procedure. This included loading cell suspension to solid surface and maintaining contact for 30 min, then staining with a mixture containing dyes. The stained cells were observed using an epifluorescent microscope and photographed using a CCD camera under UV. Metal-doped TiO2 coatings on Al plates were prepared and tested for non-UV germicidal activity without using UV. It was tested using model microorganisms such as Bakers Yeast (Saccharomyces cerevisiae), Bacillus subtilis, Pseudomonas putida, and Escherichia coli. On the basis of the germicidal activity of catalyst and the degree of damage caused to the cells, the stained cells may appear green (viable), green with red or yellow nuclei and yellow (compromised) or red (nonviable). According to their stained color, cells were counted to calculate the percentage of dead, live, and compromised cells. Compromised cells are cells that grow very slowly after reculturing indicating a degree of reversible cell damage. Screening the germicidal activity using this staining method is accurate and efficient, and requires less time than the culture-based method. A modification to the procedure for measuring germicidal activity of rough surfaces or fibrous coatings was developed. Both TiO2 and metal-doped TiO2 (Ag, Pt, Au, Cu) possess non-UV based germicidal activity. The germicidal activity of TiO2 was found to be related with its wetting property and can be improved by UV irradiation before testing. It is not greatly affected by contact time, indicating a fast acting germicidal activity.

  10. Carbonic anhydrase activators: gold nanoparticles coated with derivatized histamine, histidine, and carnosine show enhanced activatory effects on several mammalian isoforms.

    Saada, Mohamed-Chiheb; Montero, Jean-Louis; Vullo, Daniela; Scozzafava, Andrea; Winum, Jean-Yves; Supuran, Claudiu T

    2011-03-10

    Lipoic acid moieties were attached to amine or amino acids showing activating properties against the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1). The obtained lipoic acid conjugates of histamine, L-histidine methyl ester, and L-carnosine methyl ester were attached to gold nanoparticles (NPs) by reaction with Au(III) salts in reducing conditions. The CA activators (CAAs)-coated NPs showed low nanomolar activation (K(A)s of 1-9 nM) of relevant cytosolic, membrane-bound, mitochondrial, and transmembrane CA isoforms, such as CA I, II, IV, VA, VII, and XIV. These NPs also effectively activated CAs ex vivo, in whole blood experiments, with an increase of 200-280% of the CA activity. This is the first example of enzyme activation with nanoparticles and may lead to biomedical applications for conditions in which the CA activity is diminished, such as aging, Alzheimer's disease, or CA deficiency syndrome. PMID:21291238

  11. Imaging hydrogen oxidation activity of catalyst-coated perfluoro sulfonic acid-polymer electrolyte membranes using Scanning Electrochemical Microscopy

    Meera Parthasarathy; Vijayamohanan K Pillai

    2009-09-01

    Scanning Electrochemical Microscopy (SECM) is a unique technique for studying fast heterogeneous kinetics and to map reactivity gradients along the surface of an electrocatalyst, especially when it involves multiple surface sites of varying reactivity. It combines the dual advantages offered by ultramicroelectrode (UME) voltammetry in terms of reduced ohmic drop and insignificant double layer charging contribution with the advantages of imaging by rastering the UME across an electro-active surface. In this work, we demonstrate these distinctive features of SECM in evaluating reactivity gradients on catalyst (Pt/C) coated Nafion® films towards hydrogen oxidation activity, a reaction of immense technological relevance. Imaging has been performed in the feedback mode by allowing H2 evolution at the tip (25 m Pt UME), which is reoxidized at the substrate electrode containing Pt/C-Nafion film. Interesting distribution in H2 oxidation activity has been observed as a function of potential applied to the Pt/CNafion film. In addition, a plot of normalized tip current versus the substrate electrode potential indicates the effect of potential-induced reactivity change in the catalyst-coated membranes. The results of the present investigation are believed to be useful to H2/O2 PEM fuel cells with respect to evaluating reactivity gradients of catalyst-coated polymer electrolyte membranes, which is important to rectify problems related to catalyst utilization.

  12. Synthesis, characteristics and antimicrobial activity of ZnO nanoparticles

    Janaki, A. Chinnammal; Sailatha, E.; Gunasekaran, S.

    2015-06-01

    The utilization of various plant resources for the bio synthesis of metallic nano particles is called green technology and it does not utilize any harmful protocols. Present study focuses on the green synthesis of ZnO nano particles by Zinc Carbonate and utilizing the bio-components of powder extract of dry ginger rhizome (Zingiber officinale). The ZnO nano crystallites of average size range of 23-26 nm have been synthesized by rapid, simple and eco friendly method. Zinc oxide nano particles were characterized by using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX). FTIR spectra confirmed the adsorption of surfactant molecules at the surface of ZnO nanoparticles and the presence of ZnO bonding. Antimicrobial activity of ZnO nano particles was done by well diffusion method against pathogenic organisms like Klebsiella pneumonia, Staphylococcus aureus and Candida albicans and Penicillium notatum. It is observed that the ZnO synthesized in the process has the efficient antimicrobial activity.

  13. Low activation steels welding with PWHT and coating for tritium blanket module (ITER and DEMO reactors)

    Full text: Eurofer weldability is established for data base assessment and TBM manufacturing support. Electron Beam, Hybrid (Laser combined with MIG/MAG), Laser and Narrow Gap TIG processes have been carried out on Eurofer Low activation steel. Electron Beam produces very narrow fusion zone width, in the range of 3 to 4 mm, and too strong enhanced weld shape with brittle joints with δ-ferrite and pores. This process is considered only for low penetration depth (cooling plates). The other processes produce 2 families of similar results: one for Hybrid (MIG + Laser) and Laser processes, and a second one for TIG and Narrow Gap TIG processes. The first one procures less distortion and coarsened fusion zone, due to higher cooling rate. For all the welding processes, high hardness values, increasing brittleness and softening effects in the Heat Affected Zone are observed for each welding configuration that could signal creep problems. The Fusion Zones are typically composed of martensite laths, with small grain sizes. In the Heat Affected Zones, martensite grains are observed with carbide precipitation. Eurofer filler wire with optimized chemical composition is developed for producing welds with good properties and high joint coefficient value. To restore mechanical properties after welding, PWHT have been developed: single step for the first family and 2 steps for the second one. Distortions of different mock-ups with and without PWHT have been managed to assess manufacturing rules and clamping devices. Welding data base has thus been established. W coating on the TBM structure has shown no strong effect on the TBM structure. (author)

  14. Low activation steels welding with PWHT and coating for ITER Test Blanket Modules and DEMO

    Eurofer weldability is established for data base assessment and TBM manufacturing support. Electron Beam, Hybrid (Laser combined with MIG/MAG), Laser and Narrow Gap TIG processes have been carried out on Eurofer Low activation steel. Electron Beam produces very narrow fusion zone width, in the range of 3 to 4 mm, and too strong enhanced weld shape with brittle joints with δ-ferrite and pores. This process is considered only for low penetration depth (cooling plates). The other processes produce 2 families of similar results: one for Hybrid (MIG + Laser) and Laser processes, and a second one for TIG and Narrow Gap TIG processes. The first one procures less distortion and coarsened fusion zone, due to higher cooling rate. For all the welding processes, high hardness values, increasing brittleness and softening effects in the Heat Affected Zone are observed for each welding configuration that could signal creep problems. The Fusion Zones are typically composed of martensite laths, with small grain sizes. In the Heat Affected Zones, martensite grains are observed with carbide precipitation. Eurofer filler wire with optimized chemical composition is developed for producing welds with good properties and high joint coefficient value. To restore mechanical properties after welding, PWHT have been developed: single step for the first family and 2 steps for the second one. Distortions of different mock-ups with and without PWHT have been managed to assess manufacturing rules and clamping devices. Welding data base has thus been established. W coating on the TBM structure has shown no strong effect on the TBM structure. (author)

  15. Arsenic Adsorption Equilibrium Concentration and Adsorption Rate of Activated Carbon Coated with Ferric-Aluminum Hydroxides

    Zhang, M.; Sugita, H.; Oguma, T.; Hara, J.; Takahashi, S.

    2015-12-01

    In some areas of developing countries, ground or well water contaminated with arsenic has been reluctantly used as drinking water. It is highly desirable that effective and inexpensive arsenic removal agents should be developed and provided to reduce the potential health risk. Previous studies demonstrated that activated carbon coated with ferric-aluminum hydroxides (Fe-Al-C) has high adsorptive potential for removal of arsenic. In this study, a series of experiments using Fe-Al-C were carried to discuss adsorption equilibrium time, adsorption equilibrium concentration and adsorption rate of arsenic for Fe-Al-C. Fe-Al-C used in this study was provided by Astec Co., Ltd. Powder reagent of disodium hydrogen arsenate heptahydrate was dissolved into ion-exchanged water. The solution was then further diluted with ion-exchanged water to be 1 and 10 mg/L as arsenic concentration. The pH of the solution was adjusted to be around 7 by adding HCl and/or NaOH. The solution was used as artificial arsenic contaminated water in two types of experiments (arsenic adsorption equilibrium and arsenic adsorption rate tests). The results of the arsenic equilibrium tests were showed that a time period of about 3 days to reach apparent adsorption equilibrium for arsenic. The apparent adsorption equilibrium concentration and adsorbed amount of arsenic on Fe-Al-C adsorbent could be estimated by application of various adsorption isotherms, but the distribution coefficient of arsenic between solid and liquid varies with experimental conditions such as initial concentration of arsenic and addition concentration of adsorbent. An adsorption rate equation that takes into account the reduction in the number of effective adsorption sites on the adsorbent caused by the arsenic adsorption reaction was derived based on the data obtained from the arsenic adsorption rate tests.

  16. Combined effect of starch/montmorillonite coating and passive MAP in antioxidant activity, total phenolics, organic acids and volatile of fresh-cut carrots.

    Guimarães, Isabela Costa; Dos Reis, Kelen Cristina; Menezes, Evandro Galvão Tavares; Borges, Paulo Rogério Siriano; Rodrigues, Ariel Costa; Leal, Renato; Hernandes, Thais; de Carvalho, Elisângela Helena Nunes; Vilas Boas, Eduardo Valério de Barros

    2016-03-01

    This work evaluates fresh-cut carrots (FCC) coated with montmorillonite (MMT) subjected to passive modified atmosphere packaging. Carrots were sanitized, cooled, peeled and sliced. Half of the FCC were coated with MMT nanoparticle film and the other half were not. All FCCs were packed in a polypropylene rigid tray, covered with a polypropylene rigid lid or sealed with polyethylene + propylene film, in four treatments (RL, rigid lid; RLC, rigid lid + coating; ST, sealed tray; STC, sealed tray + coating). FCCs were stored at 4 °C and were analyzed weekly for 4 weeks (total antioxidant activity by 2,2-diphenyl-1-picryl hydrazyl method and the β-carotene/linoleic acid, phenolic compounds, organic acids and volatile compounds). The use of coating film with starch nanoparticles and a modified atmosphere leads to the preservation of the total antioxidant activity, the volatile and organic acids of FCC. PMID:26857136

  17. The study of steel protection effect by application of molten active microalloyed aluminum and by covering that composition by organic coating

    Purenović Milovan M.

    2002-01-01

    Full Text Available In this paper, the steel active-passive anticorrosive protection was done. Steel plates samples with dimensions 40 ×100 ×2 millimeters were used. Samples surfaces preparation was done by degreasing, then by sandblasting by pneumatic pistol. The metallising by molten metal was done by hand pistol which worked with metal vein "Protector" (ø 3,18 millimeters of electrochemical active anode material on the basis of microalloyed aluminum. The mentioned application was done twice and obtained layer thickness was 150-200 micrometers. After this operation, organic coating "Vinilpom", the product of Coatings Industry "Pomoravlje", was applied. Coating quality was followed by measuring of coating thickness, of dried film hardness, level of connecting with a base and of gloss. Whole composition steel - "Protector", organic coating electrochemical study was done by measuring of galvanic team electrochemical potential change in 20% NaCl solution, during the time.

  18. A Simple Surface Modification of NiO Cathode with TiO2 Nano-Particles for Molten Carbonate Fuel Cells (MCFCs)

    The TiO2-modified Ni powders, prepared by the simple method (ball-milling and subsequent annealing) without resorting to any complex coating process, eventually form nickel titanate passive layer at high temperature. It as good corrosion resistance in molten carbonates media and higher electrical conductivity at high temperature. In addition, the modified cathode increases the degree of lithiation during the operation of MCFC. These positive effects provide a decrease in the internal resistance and improve the cell performance. Results obtained from this study can be applied to develop the surface modification of cathode materials and the performance of molten carbonate fuel cells. Molten carbonate fuel cells (MCFCs) are efficient energy conversion devices to convert chemical energy into electrical energy through the electrochemical reaction. Because of a lot of advantages of MCFC operated at high temperature, many researchers have been trying to apply it to large-scaled power generations, marine boats, and so on. Among various cathode materials, nickel oxide, NiO, is the most widely used cathode for MCFCs due to its stability and high electrical conductivity, but the degradation of cathode material, so-called NiO dissolution, prevents a long-term operation of MCFC. In order to overcome the drawback, numerous studies have been performed. One of the most useful ways to enhance the surface property and maintain the bulk property of the host materials is the surface modification. The most common modification method is coating and these coating procedures which need some complicated steps with the use of organic materials, but it restricts the large-scale fabrication. In this study, to improve the electrochemical performance, we have prepared an alternative MCFC cathode material, TiO2-modified NiO, by simple method without resorting to any complex coating process. Results obtained in this study can provide an effective way to mass-produce the cathode materials applied

  19. CoFe2O4 nano-particles functionalized with 8-hydroxyquinoline for dispersive solid-phase micro-extraction and direct fluorometric monitoring of aluminum in human serum and water samples.

    Abdolmohammad-Zadeh, Hossein; Rahimpour, Elaheh

    2015-06-30

    A simple dispersive solid-phase micro-extraction method based on CoFe2O4 nano-particles (NPs) functionalized with 8-hydroxyquinoline (8-HQ) with the aid of sodium dodecyl sulfate (SDS) was developed for separation of Al(III) ions from aqueous solutions. Al(III) ions are separated at pH 7 via complex formation with 8-HQ using the functionalized CoFe2O4 nano-particles sol solution as a dispersed solid-phase extractor. The separated analyte is directly quantified by a spectrofluorometric method at 370nm excitation and 506nm emission wavelengths. A comparison of the fluorescence of Al(III)-8-HQ complex in bulk solution and that of Al(III) ion interacted with 8-HQ/SDS/CoFe2O4 NPs revealed a nearly 5-fold improvement in intensity. The experimental factors influencing the separation and in situ monitoring of the analyte were optimized. Under these conditions, the calibration graph was linear in the range of 0.1-300ngmL(-1) with a correlation coefficient of 0.9986. The limit of detection and limit of quantification were 0.03ngmL(-1) and 0.10ngmL(-1), respectively. The inter-day and intra-day relative standard deviations for six replicate determinations of 150ngmL(-1) Al(III) ion were 2.8% and 1.7%, respectively. The method was successfully applied to direct determine Al(III) ion in various human serum and water samples. PMID:26041520

  20. Effect of thermal treatments on sputtered silver nanocluster/silica composite coatings on soda-lime glasses: ionic exchange and antibacterial activity

    Silver nanocluster/silica composite coatings were deposited on both soda-lime and silica glasses by radio frequency (RF) co-sputtering. The effect of thermal treatments on the microstructure in the range of 150–450 °C were examined by UV–visible spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Time of Flight-Elastic Recoil Detection Analysis. Sodium/silver ionic exchange was evidenced for coatings sputtered on soda-lime substrates after heating at 450 °C; presence of silver ions and/or silver nanoclusters, nanocluster size and their position inside the sputtered layers will be discussed for as-deposited and heated coatings on both substrates. The antibacterial activity of all coatings was determined against Staphylococcus aureus and Candida albicans by disk diffusion method and colonies forming units count; in agreement with microstructural results, the antibacterial activity present on all coatings was slightly reduced after heating at 450 °C. All coatings have been submitted to humidity plus UV ageing and sterilization by autoclave, gamma ray and ethylene oxide gas. Tape resistance (ASTM D3359-97) tests have been done on each coating before and after ageing and sterilizations, revealing a good adhesion on soda-lime substrates, except for those aged in humidity plus UV and sterilized by autoclave. Scratch tests and nanoindentation tests have been done on each coating, as-deposited and after heating at 450 °C. The coating hardness was improved by heating only when coatings were deposited on silica. The heating of coatings deposited on soda-lime substrates gave opposite effect on their hardness.

  1. Effect of thermal treatments on sputtered silver nanocluster/silica composite coatings on soda-lime glasses: ionic exchange and antibacterial activity

    Ferraris, M.; Ferraris, S., E-mail: sara.ferraris@polito.it; Miola, M.; Perero, S.; Balagna, C.; Verne, E. [Politecnico di Torino, Department of Applied Science and Technology, Institute of Materials Physics and Engineering (Italy); Gautier, G. [IMAMOTER Institute for Agricultural and Earthmoving Machines (Italy); Manfredotti, Ch.; Battiato, A.; Vittone, E. [University of Torino, Physics Department, NIS Excellence Centre and CNISM (Italy); Speranza, G. [Fondazione Bruno Kessler FBK (Italy); Bogdanovic, I. [Ruder Boskovic Institute, Experimental Physics Department (Croatia)

    2012-12-15

    Silver nanocluster/silica composite coatings were deposited on both soda-lime and silica glasses by radio frequency (RF) co-sputtering. The effect of thermal treatments on the microstructure in the range of 150-450 Degree-Sign C were examined by UV-visible spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Time of Flight-Elastic Recoil Detection Analysis. Sodium/silver ionic exchange was evidenced for coatings sputtered on soda-lime substrates after heating at 450 Degree-Sign C; presence of silver ions and/or silver nanoclusters, nanocluster size and their position inside the sputtered layers will be discussed for as-deposited and heated coatings on both substrates. The antibacterial activity of all coatings was determined against Staphylococcus aureus and Candida albicans by disk diffusion method and colonies forming units count; in agreement with microstructural results, the antibacterial activity present on all coatings was slightly reduced after heating at 450 Degree-Sign C. All coatings have been submitted to humidity plus UV ageing and sterilization by autoclave, gamma ray and ethylene oxide gas. Tape resistance (ASTM D3359-97) tests have been done on each coating before and after ageing and sterilizations, revealing a good adhesion on soda-lime substrates, except for those aged in humidity plus UV and sterilized by autoclave. Scratch tests and nanoindentation tests have been done on each coating, as-deposited and after heating at 450 Degree-Sign C. The coating hardness was improved by heating only when coatings were deposited on silica. The heating of coatings deposited on soda-lime substrates gave opposite effect on their hardness.

  2. Synthesis of TBP-coated magnetic Pst-DVB particles for uranium separation

    Magnetically assisted chemical separation process is an efficient method used widely in separating radionuclides and heavy metals in environmental samples. It is simple, compact and cost-effective, with less secondary waste streams. Tributyl phosphate (TBP)-coated magnetic poly (styrene-divinylbenzene) (Pst-DVB) nano-particles were synthesized and characterized by transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer, thermogravimetry and Fourier transform infrared spectrometry. The application of TBP-coated magnetic Pst-DVB particles in separating low concentration of uranium from aqueous media was evaluated, and the equilibrium adsorption isotherm was investigated. Our results indicate that the TBP-coated magnetic Pst-DVB particles may be of potential application for uranium separation. (authors)

  3. The 42-kDa coat protein of Andean potato mottle virus acts as a transcriptional activator in yeast

    Vidal M.S.

    2002-01-01

    Full Text Available Interactions of viral proteins play an important role in the virus life cycle, especially in capsid assembly. Andean potato mottle comovirus (APMoV is a plant RNA virus with a virion formed by two coat proteins (CP42 and CP22. Both APMoV coat protein open reading frames were cloned into pGBT9 and pGAD10, two-hybrid system vectors. HF7c yeast cells transformed with the p9CP42 construct grew on yeast dropout selection media lacking tryptophan and histidine. Clones also exhibited ß-galactosidase activity in both qualitative and quantitative assays. These results suggest that CP42 protein contains an amino acid motif able to activate transcription of His3 and lacZ reporter genes in Saccharomyces cerevisiae. Several deletions of the CP42 gene were cloned into the pGBT9 vector to locate the region involved in this activation. CP42 constructions lacking 12 residues from the C-terminal region and another one with 267 residues deleted from the N-terminus are still able to activate transcription of reporter genes. However, transcription activation was not observed with construction p9CP42deltaC57, which does not contain the last 57 amino acid residues. These results demonstrate that a transcription activation domain is present at the C-terminus of CP42 between residues 267 and 374.

  4. Development of a CrN/Cu nanocomposite coating on titanium-modified stainless steel for antibacterial activity against Pseudomonas aeruginosa.

    Elangovan, T; George, Rani P; Kuppusami, P; Mangalaraj, D; Bera, Santanu; Mohandas, E; Kim, Dae-Eun

    2012-01-01

    A relatively simple method was developed to fabricate CrN/Cu nanocomposite coatings using pulsed DC magnetron sputtering for application in antibacterial activity. These nanocomposite coatings were applied on titanium (Ti)-modified stainless steel substrata (D-9 alloy) and the antibacterial activity of these coating with respect to the Gram-negative bacterium Pseudomonas aeruginosa was investigated qualitatively and quantitatively. Scanning electron microscopy, epifluorescence microscope analyses, and total viable counts confirmed that inclusion of copper in the CrN/Cu nanocomposite coatings provided antibacterial activity against P. aeruginosa. The quantitative examination of the bacterial activity of P. aeruginosa was estimated by the survival ratio as calculated from the number of viable cells which formed colonies on nutrient agar plates. PMID:22827159

  5. Polyphenol Oxidase Activity and Colour Changes of ‘Starking’ Apple Cubes Coated with Alginate and Dehydrated with Air

    Susana Daniela Sousa Fernandes; Catarina Araújo da Silva Ribeiro; Maria Filomena de Jesus Raposo; Rui Manuel Santos Costa de Morais; Alcina Maria Miranda Bernardo de Morais

    2011-01-01

    The objective was to study the effect of alginate coating on polyphenol oxidase (PPO) activity and colour of ‘Starking’ apple cubes during dehydration with hot air. Apple cubes were dehydrated at 20oC, 35oC, or 40oC, with a parallel airflow. Analysis of PPO activity, colour (L*, a*, b*) and dry matter were performed along the dehydration process at each tem...

  6. Investigation of photocatalytic activity of titanium dioxide coating deposited on aluminium alloy substrate by plasma technique

    Daviðsdóttir, Svava; Soyama, Juliano; Dirscherl, Kai;

    2011-01-01

    Nowadays, there is an increased need for functionalized surfaces with self-cleaning and antibacterial properties. Titanium dioxide (TiO2) in the anatase crystalline structure is one of the most powerful photocatalytic materials available today, which can provide above functionalities. The....... Literature consists of large number of publications on titanium dioxide coating for self-cleaning applications, with glass as the main substrate. Only little work is available on TiO2 coating of metallic alloys used for engineering applications. Engineering materials, such as light-weight aluminium and steel...

  7. Mechanisms of complement activation by dextran-coated superparamagnetic iron oxide (SPIO) nanoworms in mouse versus human serum

    Banda, Nirmal K; Mehta, Gaurav; Chao, Ying;

    2014-01-01

    mice and humans need to be fully understood. METHODS: 20 kDa dextran coated SPIO nanoworms (SPIO NW) were synthesized using Molday precipitation procedure. In vitro measurements of C3 deposition on SPIO NW using sera genetically deficient for various components of the classical pathway (CP), lectin...... the CP, but that did not affect the total level of C3 deposition on the particles. CONCLUSIONS: There were important differences and similarities in the complement activation by SPIO NW in mouse versus human sera. Understanding the mechanisms of immune recognition of nanoparticles in mouse and human......BACKGROUND: The complement system is a key component of innate immunity implicated in the neutralization and clearance of invading pathogens. Dextran coated superparamagnetic iron oxide (SPIO) nanoparticle is a promising magnetic resonance imaging (MRI) contrast agent. However, dextran SPIO has...

  8. Fe-Cr-Y2O3 MICRO-CRYSTALLINE COATINGS DEPOSITED BY SERIES ELECTRO-PULSE DISCHARGE

    Q. Xu; Y.D. He; D.R. Wang; H.B. Qi; Z.W. Li; W. Gao

    2002-01-01

    A new technique - series electro-pulse discharge (SEPD) - was developed as a sur-face coating process. In this technique, both positive and negative poles of a pulsepower were used as the depositing electrodes with the substrate alloy as an induction electrode. Fe-Cr and Fe-Cr-Y2 O3 micro-crystalline coatings were deposited on stain-less steel (Fe-18Cr-8Ni) surfaces. Oxidation at 950℃ in ambient air showed that the coatings greatly improved the oxidation resistance of the steel. The addition of dis- persed Y2O3 nano-particles into the alloy coatings was found to further reduce the scaling rate and enhance the adhesion of oxide scales.

  9. Investigation of DC magnetron-sputtered TiO2 coatings: Effect of coating thickness, structure, and morphology on photocatalytic activity

    Daviðsdóttir, Svava; Shabadi, Rajashekhara; Galca, Aurelian Catalin;

    2014-01-01

    showed that the TiO2 grains grow in dipyramidal columns having a linear increase in surface area with increased coating thickness. The refractive index values indicate also an evolutionary growth. The refractive index values obtained for the thin coatings on aluminium substrate were well below the values...

  10. CHEMICALLY DEPOSITED SILVER FILM USED AS A SERS-ACTIVE OVER COATING LAYER FOR POLYMER FILM

    Xiao-ning Liu; Gi Xue; Yun Lu; Jun Zhang; Fen-ting Li; Chen-chen Xue; Stephen Z.D. Cheng

    2001-01-01

    When colloidal silver particles were chemically deposited onto polymer film as an over-coating layer, surfaceenhanced Raman scattering (SERS) spectra could be collected for the surface analysis. SERS measurements of liquid crystal film were successfully performed without disturbing the surface morphology.

  11. Effect of Coating and Packaging Materials on Photocatalytic and Antimicrobial Activities of Titanium Dioxide Nanoparticles

    Food safety or foodborne pathogen contamination is a major concern in food industry. Titanium dioxide (TiO2) is a photocatalyst and can inactivate a wide spectrum of microorganisms under UV illumination. There is significant interest in the development of TiO2-coated or –incorporated food packaging ...

  12. Structural characterization of electric-field assisted dip-coating of gold nanoparticles on silicon

    Dushaq, Ghada H.; Alkhatib, Amro; Rasras, Mahmoud S.; Nayfeh, Ammar M. [Institute Center for microsystem engineering (iMicro), Department of Electrical Engineering and Computer Science (EECS), Masdar Institute of Science and Technology, PO Box. 54224, Abu Dhabi (United Arab Emirates)

    2015-09-15

    We report the effect of applying an electric field on the surface coverage of 40nm gold colloidal nanoparticles on silicon wafer using dip-coating and electrochemical cell set up. By applying electric field during the dip-coating of silicon wafer in a solution of gold nano particles (GNP) the surface coverage increased by 10% when the electric field varied from 5V/cm to 25V/cm at fixed deposition time of 90s. Ultra High Resolution Scanning Electron Microscopy (HRSEM) images shows that the particle agglomeration becomes more noticeable at higher electric field and as the deposition time increases from 90 s to 20 min a thin film of gold is achieved. Moreover, the results are discussed in terms of chemical bonding, electrostatic force and electrophoretic mobility of Au nano particles during the electric field enhanced deposition on the Si surface. Applied voltage, time of dipping, concentration of the aqueous solution, and particles zeta potential are all can be controlled to enhance the uniformity and particles profile on the silicon surface.

  13. Structural characterization of electric-field assisted dip-coating of gold nanoparticles on silicon

    Ghada H. Dushaq

    2015-09-01

    Full Text Available We report the effect of applying an electric field on the surface coverage of 40nm gold colloidal nanoparticles on silicon wafer using dip-coating and electrochemical cell set up. By applying electric field during the dip-coating of silicon wafer in a solution of gold nano particles (GNP the surface coverage increased by 10% when the electric field varied from 5V/cm to 25V/cm at fixed deposition time of 90s. Ultra High Resolution Scanning Electron Microscopy (HRSEM images shows that the particle agglomeration becomes more noticeable at higher electric field and as the deposition time increases from 90 s to 20 min a thin film of gold is achieved. Moreover, the results are discussed in terms of chemical bonding, electrostatic force and electrophoretic mobility of Au nano particles during the electric field enhanced deposition on the Si surface. Applied voltage, time of dipping, concentration of the aqueous solution, and particles zeta potential are all can be controlled to enhance the uniformity and particles profile on the silicon surface.

  14. Structural characterization of electric-field assisted dip-coating of gold nanoparticles on silicon

    We report the effect of applying an electric field on the surface coverage of 40nm gold colloidal nanoparticles on silicon wafer using dip-coating and electrochemical cell set up. By applying electric field during the dip-coating of silicon wafer in a solution of gold nano particles (GNP) the surface coverage increased by 10% when the electric field varied from 5V/cm to 25V/cm at fixed deposition time of 90s. Ultra High Resolution Scanning Electron Microscopy (HRSEM) images shows that the particle agglomeration becomes more noticeable at higher electric field and as the deposition time increases from 90 s to 20 min a thin film of gold is achieved. Moreover, the results are discussed in terms of chemical bonding, electrostatic force and electrophoretic mobility of Au nano particles during the electric field enhanced deposition on the Si surface. Applied voltage, time of dipping, concentration of the aqueous solution, and particles zeta potential are all can be controlled to enhance the uniformity and particles profile on the silicon surface

  15. Structural characterization of electric-field assisted dip-coating of gold nanoparticles on silicon

    Dushaq, Ghada H.; Alkhatib, Amro; Rasras, Mahmoud S.; Nayfeh, Ammar M.

    2015-09-01

    We report the effect of applying an electric field on the surface coverage of 40nm gold colloidal nanoparticles on silicon wafer using dip-coating and electrochemical cell set up. By applying electric field during the dip-coating of silicon wafer in a solution of gold nano particles (GNP) the surface coverage increased by 10% when the electric field varied from 5V/cm to 25V/cm at fixed deposition time of 90s. Ultra High Resolution Scanning Electron Microscopy (HRSEM) images shows that the particle agglomeration becomes more noticeable at higher electric field and as the deposition time increases from 90 s to 20 min a thin film of gold is achieved. Moreover, the results are discussed in terms of chemical bonding, electrostatic force and electrophoretic mobility of Au nano particles during the electric field enhanced deposition on the Si surface. Applied voltage, time of dipping, concentration of the aqueous solution, and particles zeta potential are all can be controlled to enhance the uniformity and particles profile on the silicon surface.

  16. Effect of active screen plasma nitriding pretreatment on wear behavior of TiN coating deposited by PACVD technique

    Raoufi, M., E-mail: raoufi@iust.ac.ir [School of Metallurgical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Mirdamadi, Sh. [School of Metallurgical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Mahboubi, F. [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Ahangarani, Sh. [Advanced Materials and Renewable Energies Dep., Iranian Research Organization for Science and Technology (Iran, Islamic Republic of); Mahdipoor, M.S. [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Elmkhah, H. [Department of Metallurgical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2012-08-01

    Titanium based alloys are used extensively for improving wear properties of different parts due to their high hardness contents. Titanium nitride (TiN) is among these coatings which can be deposited on surface using various techniques such as CVD, PVD and PACVD. Their weak interface with substrate is one major drawback which can increase the total wear in spite of favorite wear behavior of TiN. Disc shaped samples from AISI H13 (DIN 1.2344) steel were prepared in this study. Single TiN coating was deposited on some of them while others have experienced a TiN deposition by active screen plasma nitriding (ASPN). Hardness at the surface and depth of samples was measured through Vickers micro hardness test which revealed 1810 Hv hardness as the maximum values for a dual-layered ASPN-TiN. Pin-on-disc wear test was done in order to study the wear mechanism. In this regard, the wear behavior of samples was investigated against pins from 100Cr6 (Din 1.3505) bearing steel and tungsten carbide-cobalt (WC-Co) steel. It was evidenced that the dual-layer ASPN-TiN coating has shown the least weight loss with the best wearing behavior because of its high hardness values, stable interface and acceptable resistance against peeling during wearing period.

  17. Effect of active screen plasma nitriding pretreatment on wear behavior of TiN coating deposited by PACVD technique

    Titanium based alloys are used extensively for improving wear properties of different parts due to their high hardness contents. Titanium nitride (TiN) is among these coatings which can be deposited on surface using various techniques such as CVD, PVD and PACVD. Their weak interface with substrate is one major drawback which can increase the total wear in spite of favorite wear behavior of TiN. Disc shaped samples from AISI H13 (DIN 1.2344) steel were prepared in this study. Single TiN coating was deposited on some of them while others have experienced a TiN deposition by active screen plasma nitriding (ASPN). Hardness at the surface and depth of samples was measured through Vickers micro hardness test which revealed 1810 Hv hardness as the maximum values for a dual-layered ASPN-TiN. Pin-on-disc wear test was done in order to study the wear mechanism. In this regard, the wear behavior of samples was investigated against pins from 100Cr6 (Din 1.3505) bearing steel and tungsten carbide-cobalt (WC-Co) steel. It was evidenced that the dual-layer ASPN-TiN coating has shown the least weight loss with the best wearing behavior because of its high hardness values, stable interface and acceptable resistance against peeling during wearing period.

  18. Influence of nickel ion release on leukocyte activation: a study with coated and non-coated NiTi shape memory alloys

    Esenwein, S.A.; Bogdanski, D.; Habijan, T. [Department of Surgery, BG Kliniken Bergmannsheil, Ruhr-University of Bochum, Buerkle-de-la-Camp-Platz 1, D-44789 Bochum (Germany); Pohl, M. [Faculty of Mechanical Engineering, Materials Testing, Ruhr-University of Bochum (Germany); Epple, M. [Institute for Inorganic Chemistry, University of Duisburg-Essen, Essen (Germany); Muhr, G.; Koeller, M. [Department of Surgery, BG Kliniken Bergmannsheil, Ruhr-University of Bochum, Buerkle-de-la-Camp-Platz 1, D-44789 Bochum (Germany)

    2008-05-25

    Owing to their mechanical and thermal memory properties, nickel-titanium shape memory alloys (NiTi-SMA) are very interesting for biomedical applications. In most cases, medical implants are initially exposed to a blood-containing environment. The potential release of Ni ions needs to be considered because it counteracts a good biocompatibility and may well influence the release of mediators from adherent and surrounding leukocytes. Two different leukocyte fractions (PMN, PBMC) were isolated from peripheral blood and were added to calcium phosphate-coated or non-coated NiTi. The supernatants were analyzed for cytokine content. Ni-ion release of coated, non-coated and etched NiTi samples was analyzed by graphite furnace atomic absorption spectrometry. Additionally, cytokine release studies were performed with exogenously added Ni ions. In the presence of NiTi a significant, but low increase in the release of IL-1ra, IL-6 and IL-8 was observed. In contrast, coated NiTi led to an elevated release of all analyzed cytokines. Ni-ion release ranged from 60 {mu}g/l (non-coated NiTi) to 8 mg/l (coated or etched NiTi). Incubations of leukocytes and exogenously added Ni chloride ({<=}2.4 mg/l) did not lead to a significant modulation in cytokine generation. An increased cytokine release was only observed at 24 mg/l Ni chloride.

  19. Development of new active packaging films coated with natural phenolic compounds to improve the oxidative stability of beef.

    Barbosa-Pereira, Letricia; Aurrekoetxea, Goizane P; Angulo, Inmaculada; Paseiro-Losada, Perfecto; Cruz, José M

    2014-06-01

    The aim is to develop active packaging films containing natural antioxidants and to evaluate their capacity to enhance the oxidative stability of beef during refrigeration. The antioxidant activity of a natural extract obtained from a brewery residual waste was evaluated and compared with that of a commercial rosemary extract and two synthetic antioxidants (BHT and propyl gallate). Different concentrations of each antioxidant were also added directly to beef samples, resulting in a reduction in lipid oxidation of up to 70-80% relative to the control. Active antioxidant films coated with PVPP-WS extract reduced lipid oxidation by up to 80%, relative to the control, during cold storage. The use of active packaging films containing natural extracts could improve the oxidative stability of meat products and should therefore be of great interest in the food industry. PMID:24598072

  20. Antimicrobial activity of novel nanostructured Cu-SiO2 coatings prepared by chemical vapour deposition against hospital related pathogens.

    Varghese, Sajnu; Elfakhri, Souad O; Sheel, David W; Sheel, Paul; Bolton, Frederick J Eric; Foster, Howard A

    2013-01-01

    There is increasing recognition that the healthcare environment acts as an important reservoir for transmission of healthcare acquired infections (HCAI). One method of reducing environmental contamination would be use of antimicrobial materials. The antimicrobial activity of thin silica-copper films prepared by chemical vapour deposition was evaluated against standard strains of bacteria used for disinfectant testing and bacteria of current interest in HCAI. The structure of the coatings was determined using Scanning Electron Microscopy and their hardness and adhesion to the substrate determined. Antimicrobial activity was tested using a method based on BS ISO 22196:2007. The coatings had a pale green-brown colour and had a similar hardness to steel. SEM showed nano-structured aggregates of Cu within a silica matrix. A log10 reduction in viability of >5 could be obtained within 4 h for the disinfectant test strains and within 6 h for producing Acinetobacter baumannii, Klebsiella pneumoniae and Stenotrophomonas maltophilia. Activity against the other hospital isolates was slower but still gave log10 reduction factors of >5 for extended spectrum β-lactamase producing Escherichia coli and >3 for vancomycin resistant Enterococcus faecium, methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa within 24 h. The results demonstrate the importance of testing antimicrobial materials destined for healthcare use against isolates of current interest in hospitals as well as standard test strains. The coatings used here can also be applied to substrates such as metals and ceramics and have potential applications where reduction of microbial environmental contamination is desirable. PMID:24007899