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The Application of Electrospun Photocatalytic BiFeO3 Nanofibers in Water TreatmentMojir Shaibani, Parmiss Unknown Date
No description available.
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Nanoparticles and nanofibers production using supercritical carbon dioxideThakur, Ranjit, January 2005 (has links) (PDF)
Thesis (Ph.D.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.
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Processing, characterization and modeling of carbon nanofiber modified carbon/carbon compositesSamalot Rivera, Francis J. January 2007 (has links) (PDF)
Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Additional advisors: Krishan K. Chawla, Derrick Dean, Yogesh Vohra, Mark Weaver. Description based on contents viewed Feb. 13, 2009; title from PDF t.p. Includes bibliographical references (p. 174-186).
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Functionalized electrospun nanofibers impregnated with nanoparticles for degradation of chlorinated compoundsMapazi, Odwa 01 July 2014 (has links)
M.Sc. (Nanoscience) / Supported bimetallic Fe/Ni nanoparticles have been used for years as catalysts for the dechlorination of organochlorine compounds in ground water remediation. However, their fate and potential harm to the environment is of concern, hence, ways of reducing these negative aspects are being explored. As a way to solve this problem, catalytic nanoparticles are immobilised on a variety of substrates ranging from membranes, clays, silica, etc. In the current effort, the immobilisation of Fe/Ni bimetallic nanoparticles on electospun cellulose-based nanofibers was examined with the ultimate view to apply the materials for dechlorination studies. Fe/Ni bimetallic nanoparticles were anchored on ligand-functionalised cellulose nanofibers by the successive reduction of Fe(II) and Ni(II) ions from their respective solutions using NaBH₄...
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Multiscale modeling and simulation of nanocrystalline zirconium oxideWang, Chaojun. January 2009 (has links)
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed February 25, 2010). PDF text: 164 p. : ill. (some col.) ; 4 Mb. UMI publication number: AAT 3386603. Includes bibliographical references. Also available in microfilm and microfiche formats.
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Fly ash catalysed synthesis of CNFs for use in a photocatalytic CNF-TiO2 hybridMoya, Arthur Ndumiso January 2016 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2016. / This study has explored the CVD synthesis of carbon nanofibres (CNFs) using Eskom’s
waste coal fly ash as a catalyst with acetylene and hydrogen as the carbon source and
carrier gas, respectively. In the process, a possible growth mechanism for these carbon
nanofibres was sought. CNFs were successfully synthesised from fly ash and were found to
have an average diameter of 22±7 nm.
The growth mechanism of these CNFs was studied using EDS, TEM and laser Raman
spectroscopy. It was observed that CNFs grew via root growth on spherical particles of fly
ash and by tip growth on irregular-shaped metal oxide agglomerates. Both of these were
found, through EDS analysis, to be Fe-rich.
CNFs were functionalised between 2-12 h under reflux at 110 °C using a 3:1 (v/v)
combination of HNO3 and H2SO4 in order to introduce functional groups onto their surfaces
to act as anchors for hydrophilic reactants. The functionalisation of these CNFs was studied
using TEM, laser Raman spectroscopy, ATR-FTIR spectroscopy, PXRD, BET, XRF and TGA.
ATR-FTIR spectroscopy showed that some carbonyl functional groups were present on the
surfaces of these CNFs after functionalisation.
The functionalised CNFs (fCNFs) were then treated using a simple hydrothermal method to
deposit 10% (m/m) of TiO2 nanoparticles onto their surface. This hydrothermal method
employed the drop-wise addition of TiCl4 to a cold water-fCNFs mixture, which was then
refluxed at 115 °C for 2-12 h. Laser Raman spectroscopy confirmed the presence of both
TiO2 (phase pure anatase) and CNFs. ATR-FTIR spectroscopy provisionally revealed the
presence of covalent Ti-O-C bonds.
Studies where the duration of exposure to TiCl4 and the functionalisation time of CNFs
were examined showed that the particle size and agglomeration of the TiO2 nanoparticles
did not affect the surface area of the CNF-TiO2 hybrids significantly. However, CNF-TiO2
hybrids which were shown by TGA to have high fly ash content were observed to have low
surface areas. fCNFs functionalised at 2 h had the highest surface area, at all fixed durations
of exposure to TiCl4 by comparison with fCNFs which had been functionalised for longer
periods. / GR2016
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Synthesis of copper nanoparticles contained in mesoporous hollow carbon spheres as potential catalysts for growing helical carbon nanofibersMagubane, Alice January 2017 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment for the degree of Master of Science in Chemistry, 2017 / The aim of this study was to synthesize helical carbon nanofibers with controlled diameter by
using copper nanoparticles contained inside hollow carbon sphere. In this work, different
methods have been explored to synthesize copper nanoparticles contained inside mesoporous
hollow carbon spheres in order to minimize the sintering effect of the copper nanoparticles.
Mesoporous hollow carbon spheres were used not only as a support for the copper nanoparticles
but to stabilize and disperse these nanoparticles to prevent the formation of aggregates.
Mesoporous hollow carbon spheres were synthesized using a hard templating method, in which
mesoporous silica spheres or polystyrene spheres were used as a sacrificial template. Carbon
nanofibers with different morphologies, including straight and helical fibers were obtained by a
chemical vapor deposition method where acetylene was decomposed over copper nanoparticles
contained inside mesoporous hollow carbon spheres catalyst at 350 °C. The synthesized carbon
nanofibers were grown on the surface of the mesoporous hollow carbon spheres as the methods
used to synthesize the catalyst failed to incorporate copper nanoparticles inside the spheres.
Differences in the diameter of the straight and helical carbon nanofibers were observed from
both catalysts. This supports the important effect of particle size on influencing the shape of the
synthesized carbon nanofibers. / XL2018
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Nanotechology in concrete: review and statistical analysisUnknown Date (has links)
This thesis investigates the use of nanotechnology in an extensive literature search in the field of cement and concrete. A summary is presented. The research was divided into two categories: (1) nanoparticles and (2) nanofibers and nanotubes. The successes and challenges of each category is documented in this thesis. The data from the literature search is taken and analyzed using statistical prediction by the use of the Monte Carlo and Bayesian methods. It shows how statistical prediction can be used to analyze patterns and trends and also discover optimal additive dosages for concrete mixes. / by Jonathan Glenn. / Thesis (M.S.C.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.
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Structure-property-relationships of carbon nanotubes/nanofibres and their polymer compositesSandler, Jan K. W. January 2005 (has links)
No description available.
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Production, Characterization, and Mechanical Behavior of Cementitious Materials Incorporating Carbon NanofibersYazdanbakhsh, Ardavan 2012 August 1900 (has links)
Carbon nanotubes (CNTs) and carbon nanofirbers (CNFs) have excellent properties (mechanical, electrical, magnetic, etc.), which can make them effective nanoreinforcements for improving the properties of materials. The incorporation of CNT/Fs in a wide variety of materials has been researched extensively in the past decade. However, the past study on the reinforcement of cementitious materials with these nanofilaments has been limited. The findings from those studies indicate that CNT/Fs did not significantly improve the mechanical properties of cementitious materials. Two major parameters influence the effectiveness of any discrete inclusion in composite material: The dispersion quality of the inclusions and the interfacial bond between the inclusions and matrix. The main focus of this dissertation is on the dispersion factor, and consists of three main tasks: First a novel thermodynamic-based method for dispersion quantification was developed. Second, a new method, incorporating the utilization of silica fume, was devised to improve and stabilize the dispersion of CNFs in cement paste. And third, the dispersion quantification method and mechanical testing were employed to measure, compare, and correlate the dispersion and mechanical properties of CNF-incorporated cement paste produced with the conventional and new methods. Finally, the main benefits, including the increase in strength and resistance to shrinkage cracking, obtained from the utilization of CNFs in cement paste will be presented.
The investigations and the corresponding results show that the novel dispersion quantification method can be implemented easily to perform a wide variety of tasks ranging from measuring dispersion of nanofilaments in composites using their optical/SEM micrographs as input, to measuring the effect of cement particle/clump size on the dispersion of nano inclusions in cement paste. It was found that cement particles do not affect the dispersion of nano inclusions in cement paste significantly while the dispersion of nano inclusions can notably degenerates if the cement particles are agglomerated. The novel dispersion quantification method shows that, the dispersion of CNFs in cement paste significantly improves by utilizing silica fume. However, it was found that the dispersion of silica fume particles is an important parameter and poorly dispersed silica fume cannot enhance the overall dispersion of nano inclusions in cementitious materials. Finally, the mechanical testing and experimentations showed that CNFs, in absence of moist curing, even if poorly dispersed, can provide important benefits in terms of strength and crack resistance.
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